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- qasper-0033/instruction.md +673 -0
- qasper-0034/instruction.md +673 -0
- qasper-0050/instruction.md +56 -0
- qasper-0056/instruction.md +3 -0
- qasper-0057/instruction.md +3 -0
- qasper-0058/instruction.md +3 -0
- qasper-0059/instruction.md +3 -0
- qasper-0060/instruction.md +70 -0
- qasper-0061/instruction.md +3 -0
- qasper-0066/instruction.md +154 -0
- qasper-0067/instruction.md +3 -0
- qasper-0068/instruction.md +154 -0
- qasper-0069/instruction.md +121 -0
- qasper-0092/instruction.md +77 -0
- qasper-0093/instruction.md +3 -0
- qasper-0094/instruction.md +52 -0
- qasper-0095/instruction.md +3 -0
- qasper-0104/instruction.md +3 -0
- qasper-0112/instruction.md +3 -0
- qasper-0113/instruction.md +47 -0
- qasper-0114/instruction.md +98 -0
- qasper-0115/instruction.md +98 -0
- qasper-0122/instruction.md +86 -0
- qasper-0123/instruction.md +3 -0
- qasper-0124/instruction.md +93 -0
- qasper-0125/instruction.md +3 -0
- qasper-0140/instruction.md +110 -0
- qasper-0141/instruction.md +116 -0
- qasper-0146/instruction.md +134 -0
- qasper-0147/instruction.md +131 -0
- qasper-0148/instruction.md +131 -0
- qasper-0149/instruction.md +3 -0
- qasper-0156/instruction.md +3 -0
- qasper-0158/instruction.md +123 -0
- qasper-0160/instruction.md +3 -0
- qasper-0167/instruction.md +3 -0
- qasper-0169/instruction.md +3 -0
- qasper-0170/instruction.md +3 -0
- qasper-0171/instruction.md +3 -0
- qasper-0176/instruction.md +89 -0
- qasper-0177/instruction.md +3 -0
- qasper-0178/instruction.md +3 -0
- qasper-0179/instruction.md +89 -0
- qasper-0182/instruction.md +3 -0
- qasper-0183/instruction.md +120 -0
- qasper-0184/instruction.md +107 -0
- qasper-0185/instruction.md +3 -0
- qasper-0193/instruction.md +112 -0
- qasper-0194/instruction.md +3 -0
- qasper-0201/instruction.md +124 -0
qasper-0033/instruction.md
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| 1 |
+
Name of Paper: Stay On-Topic: Generating Context-specific Fake Restaurant Reviews
|
| 2 |
+
|
| 3 |
+
Question: Which dataset do they use a starting point in generating fake reviews?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Background",
|
| 12 |
+
"System Model",
|
| 13 |
+
"Attack Model",
|
| 14 |
+
"Generative Model"
|
| 15 |
+
],
|
| 16 |
+
"paragraphs": [
|
| 17 |
+
[
|
| 18 |
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"Automatically generated fake reviews have only recently become natural enough to fool human readers. Yao et al. BIBREF0 use a deep neural network (a so-called 2-layer LSTM BIBREF1 ) to generate fake reviews, and concluded that these fake reviews look sufficiently genuine to fool native English speakers. They train their model using real restaurant reviews from yelp.com BIBREF2 . Once trained, the model is used to generate reviews character-by-character. Due to the generation methodology, it cannot be easily targeted for a specific context (meaningful side information). Consequently, the review generation process may stray off-topic. For instance, when generating a review for a Japanese restaurant in Las Vegas, the review generation process may include references to an Italian restaurant in Baltimore. The authors of BIBREF0 apply a post-processing step (customization), which replaces food-related words with more suitable ones (sampled from the targeted restaurant). The word replacement strategy has drawbacks: it can miss certain words and replace others independent of their surrounding words, which may alert savvy readers. As an example: when we applied the customization technique described in BIBREF0 to a review for a Japanese restaurant it changed the snippet garlic knots for breakfast with garlic knots for sushi).",
|
| 19 |
+
"We propose a methodology based on neural machine translation (NMT) that improves the generation process by defining a context for the each generated fake review. Our context is a clear-text sequence of: the review rating, restaurant name, city, state and food tags (e.g. Japanese, Italian). We show that our technique generates review that stay on topic. We can instantiate our basic technique into several variants. We vet them on Amazon Mechanical Turk and find that native English speakers are very poor at recognizing our fake generated reviews. For one variant, the participants' performance is close to random: the class-averaged F-score of detection is INLINEFORM0 (whereas random would be INLINEFORM1 given the 1:6 imbalance in the test). Via a user study with experienced, highly educated participants, we compare this variant (which we will henceforth refer to as NMT-Fake* reviews) with fake reviews generated using the char-LSTM-based technique from BIBREF0 .",
|
| 20 |
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"We demonstrate that NMT-Fake* reviews constitute a new category of fake reviews that cannot be detected by classifiers trained only using previously known categories of fake reviews BIBREF0 , BIBREF3 , BIBREF4 . Therefore, NMT-Fake* reviews may go undetected in existing online review sites. To meet this challenge, we develop an effective classifier that detects NMT-Fake* reviews effectively (97% F-score). Our main contributions are:"
|
| 21 |
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],
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| 22 |
+
[
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| 23 |
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"Fake reviews User-generated content BIBREF5 is an integral part of the contemporary user experience on the web. Sites like tripadvisor.com, yelp.com and Google Play use user-written reviews to provide rich information that helps other users choose where to spend money and time. User reviews are used for rating services or products, and for providing qualitative opinions. User reviews and ratings may be used to rank services in recommendations. Ratings have an affect on the outwards appearance. Already 8 years ago, researchers estimated that a one-star rating increase affects the business revenue by 5 \u2013 9% on yelp.com BIBREF6 .",
|
| 24 |
+
"Due to monetary impact of user-generated content, some businesses have relied on so-called crowd-turfing agents BIBREF7 that promise to deliver positive ratings written by workers to a customer in exchange for a monetary compensation. Crowd-turfing ethics are complicated. For example, Amazon community guidelines prohibit buying content relating to promotions, but the act of writing fabricated content is not considered illegal, nor is matching workers to customers BIBREF8 . Year 2015, approximately 20% of online reviews on yelp.com were suspected of being fake BIBREF9 .",
|
| 25 |
+
"Nowadays, user-generated review sites like yelp.com use filters and fraudulent review detection techniques. These factors have resulted in an increase in the requirements of crowd-turfed reviews provided to review sites, which in turn has led to an increase in the cost of high-quality review. Due to the cost increase, researchers hypothesize the existence of neural network-generated fake reviews. These neural-network-based fake reviews are statistically different from human-written fake reviews, and are not caught by classifiers trained on these BIBREF0 .",
|
| 26 |
+
"Detecting fake reviews can either be done on an individual level or as a system-wide detection tool (i.e. regulation). Detecting fake online content on a personal level requires knowledge and skills in critical reading. In 2017, the National Literacy Trust assessed that young people in the UK do not have the skillset to differentiate fake news from real news BIBREF10 . For example, 20% of children that use online news sites in age group 12-15 believe that all information on news sites are true.",
|
| 27 |
+
"Neural Networks Neural networks are function compositions that map input data through INLINEFORM0 subsequent layers: DISPLAYFORM0 ",
|
| 28 |
+
"where the functions INLINEFORM0 are typically non-linear and chosen by experts partly for known good performance on datasets and partly for simplicity of computational evaluation. Language models (LMs) BIBREF11 are generative probability distributions that assign probabilities to sequences of tokens ( INLINEFORM1 ): DISPLAYFORM0 ",
|
| 29 |
+
"such that the language model can be used to predict how likely a specific token at time step INLINEFORM0 is, based on the INLINEFORM1 previous tokens. Tokens are typically either words or characters.",
|
| 30 |
+
"For decades, deep neural networks were thought to be computationally too difficult to train. However, advances in optimization, hardware and the availability of frameworks have shown otherwise BIBREF1 , BIBREF12 . Neural language models (NLMs) have been one of the promising application areas. NLMs are typically various forms of recurrent neural networks (RNNs), which pass through the data sequentially and maintain a memory representation of the past tokens with a hidden context vector. There are many RNN architectures that focus on different ways of updating and maintaining context vectors: Long Short-Term Memory units (LSTM) and Gated Recurrent Units (GRUs) are perhaps most popular. Neural LMs have been used for free-form text generation. In certain application areas, the quality has been high enough to sometimes fool human readers BIBREF0 . Encoder-decoder (seq2seq) models BIBREF13 are architectures of stacked RNNs, which have the ability to generate output sequences based on input sequences. The encoder network reads in a sequence of tokens, and passes it to a decoder network (a LM). In contrast to simpler NLMs, encoder-decoder networks have the ability to use additional context for generating text, which enables more accurate generation of text. Encoder-decoder models are integral in Neural Machine Translation (NMT) BIBREF14 , where the task is to translate a source text from one language to another language. NMT models additionally use beam search strategies to heuristically search the set of possible translations. Training datasets are parallel corpora; large sets of paired sentences in the source and target languages. The application of NMT techniques for online machine translation has significantly improved the quality of translations, bringing it closer to human performance BIBREF15 .",
|
| 31 |
+
"Neural machine translation models are efficient at mapping one expression to another (one-to-one mapping). Researchers have evaluated these models for conversation generation BIBREF16 , with mixed results. Some researchers attribute poor performance to the use of the negative log likelihood cost function during training, which emphasizes generation of high-confidence phrases rather than diverse phrases BIBREF17 . The results are often generic text, which lacks variation. Li et al. have suggested various augmentations to this, among others suppressing typical responses in the decoder language model to promote response diversity BIBREF17 ."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"We discuss the attack model, our generative machine learning method and controlling the generative process in this section."
|
| 35 |
+
],
|
| 36 |
+
[
|
| 37 |
+
"Wang et al. BIBREF7 described a model of crowd-turfing attacks consisting of three entities: customers who desire to have fake reviews for a particular target (e.g. their restaurant) on a particular platform (e.g. Yelp), agents who offer fake review services to customers, and workers who are orchestrated by the agent to compose and post fake reviews.",
|
| 38 |
+
"Automated crowd-turfing attacks (ACA) replace workers by a generative model. This has several benefits including better economy and scalability (human workers are more expensive and slower) and reduced detectability (agent can better control the rate at which fake reviews are generated and posted).",
|
| 39 |
+
"We assume that the agent has access to public reviews on the review platform, by which it can train its generative model. We also assume that it is easy for the agent to create a large number of accounts on the review platform so that account-based detection or rate-limiting techniques are ineffective against fake reviews.",
|
| 40 |
+
"The quality of the generative model plays a crucial role in the attack. Yao et al. BIBREF0 propose the use of a character-based LSTM as base for generative model. LSTMs are not conditioned to generate reviews for a specific target BIBREF1 , and may mix-up concepts from different contexts during free-form generation. Mixing contextually separate words is one of the key criteria that humans use to identify fake reviews. These may result in violations of known indicators for fake content BIBREF18 . For example, the review content may not match prior expectations nor the information need that the reader has. We improve the attack model by considering a more capable generative model that produces more appropriate reviews: a neural machine translation (NMT) model."
|
| 41 |
+
],
|
| 42 |
+
[
|
| 43 |
+
"We propose the use of NMT models for fake review generation. The method has several benefits: 1) the ability to learn how to associate context (keywords) to reviews, 2) fast training time, and 3) a high-degree of customization during production time, e.g. introduction of specific waiter or food items names into reviews.",
|
| 44 |
+
"NMT models are constructions of stacked recurrent neural networks (RNNs). They include an encoder network and a decoder network, which are jointly optimized to produce a translation of one sequence to another. The encoder rolls over the input data in sequence and produces one INLINEFORM0 -dimensional context vector representation for the sentence. The decoder then generates output sequences based on the embedding vector and an attention module, which is taught to associate output words with certain input words. The generation typically continues until a specific EOS (end of sentence) token is encountered. The review length can be controlled in many ways, e.g. by setting the probability of generating the EOS token to zero until the required length is reached.",
|
| 45 |
+
"NMT models often also include a beam search BIBREF14 , which generates several hypotheses and chooses the best ones amongst them. In our work, we use the greedy beam search technique. We forgo the use of additional beam searches as we found that the quality of the output was already adequate and the translation phase time consumption increases linearly for each beam used.",
|
| 46 |
+
"We use the Yelp Challenge dataset BIBREF2 for our fake review generation. The dataset (Aug 2017) contains 2.9 million 1 \u20135 star restaurant reviews. We treat all reviews as genuine human-written reviews for the purpose of this work, since wide-scale deployment of machine-generated review attacks are not yet reported (Sep 2017) BIBREF19 . As preprocessing, we remove non-printable (non-ASCII) characters and excessive white-space. We separate punctuation from words. We reserve 15,000 reviews for validation and 3,000 for testing, and the rest we use for training. NMT models require a parallel corpus of source and target sentences, i.e. a large set of (source, target)-pairs. We set up a parallel corpus by constructing (context, review)-pairs from the dataset. Next, we describe how we created our input context.",
|
| 47 |
+
"The Yelp Challenge dataset includes metadata about restaurants, including their names, food tags, cities and states these restaurants are located in. For each restaurant review, we fetch this metadata and use it as our input context in the NMT model. The corresponding restaurant review is similarly set as the target sentence. This method produced 2.9 million pairs of sentences in our parallel corpus. We show one example of the parallel training corpus in Example 1 below:",
|
| 48 |
+
"5 Public House Las Vegas NV Gastropubs Restaurants > Excellent",
|
| 49 |
+
"food and service . Pricey , but well worth it . I would recommend",
|
| 50 |
+
"the bone marrow and sampler platter for appetizers . \\end{verbatim}",
|
| 51 |
+
" ",
|
| 52 |
+
" ",
|
| 53 |
+
"\\noindent The order {\\textbf{[rating name city state tags]}} is kept constant.",
|
| 54 |
+
"Training the model conditions it to associate certain sequences of words in the input sentence with others in the output.",
|
| 55 |
+
" ",
|
| 56 |
+
"\\subsubsection{Training Settings}",
|
| 57 |
+
" ",
|
| 58 |
+
"We train our NMT model on a commodity PC with a i7-4790k CPU (4.00GHz), with 32GB RAM and one NVidia GeForce GTX 980 GPU. Our system can process approximately 1,300 \\textendash 1,500 source tokens/s and approximately 5,730 \\textendash 5,830 output tokens/s. Training one epoch takes in average 72 minutes. The model is trained for 8 epochs, i.e. over night. We call fake review generated by this model \\emph{NMT-Fake reviews}. We only need to train one model to produce reviews of different ratings.",
|
| 59 |
+
"We use the training settings: adam optimizer \\cite{kingma2014adam} with the suggested learning rate 0.001 \\cite{klein2017opennmt}. For most parts, parameters are at their default values. Notably, the maximum sentence length of input and output is 50 tokens by default.",
|
| 60 |
+
"We leverage the framework openNMT-py \\cite{klein2017opennmt} to teach the our NMT model.",
|
| 61 |
+
"We list used openNMT-py commands in Appendix Table~\\ref{table:openNMT-py_commands}.",
|
| 62 |
+
" ",
|
| 63 |
+
"\\begin{figure}[t]",
|
| 64 |
+
"\\begin{center}",
|
| 65 |
+
" \\begin{tabular}{ | l | }",
|
| 66 |
+
" \\hline",
|
| 67 |
+
"Example 2. Greedy NMT \\\\",
|
| 68 |
+
"Great food, \\underline{great} service, \\underline{great} \\textit{\\textit{beer selection}}. I had the \\textit{Gastropubs burger} and it",
|
| 69 |
+
"\\\\",
|
| 70 |
+
"was delicious. The \\underline{\\textit{beer selection}} was also \\underline{great}. \\\\",
|
| 71 |
+
"\\\\",
|
| 72 |
+
"Example 3. NMT-Fake* \\\\",
|
| 73 |
+
"I love this restaurant. Great food, great service. It's \\textit{a little pricy} but worth\\\\",
|
| 74 |
+
"it for the \\textit{quality} of the \\textit{beer} and atmosphere you can see in \\textit{Vegas}",
|
| 75 |
+
"\\\\",
|
| 76 |
+
" \\hline",
|
| 77 |
+
" \\end{tabular}",
|
| 78 |
+
" \\label{table:output_comparison}",
|
| 79 |
+
"\\end{center}",
|
| 80 |
+
"\\caption{Na\\\"{i}ve text generation with NMT vs. generation using our NTM model. Repetitive patterns are \\underline{underlined}. Contextual words are \\emph{italicized}. Both examples here are generated based on the context given in Example~1.}",
|
| 81 |
+
"\\label{fig:comparison}",
|
| 82 |
+
"\\end{figure}",
|
| 83 |
+
" ",
|
| 84 |
+
"\\subsection{Controlling generation of fake reviews}",
|
| 85 |
+
"\\label{sec:generating}",
|
| 86 |
+
" ",
|
| 87 |
+
"Greedy NMT beam searches are practical in many NMT cases. However, the results are simply repetitive, when naively applied to fake review generation (See Example~2 in Figure~\\ref{fig:comparison}).",
|
| 88 |
+
"The NMT model produces many \\emph{high-confidence} word predictions, which are repetitive and obviously fake. We calculated that in fact, 43\\% of the generated sentences started with the phrase ``Great food''. The lack of diversity in greedy use of NMTs for text generation is clear.",
|
| 89 |
+
" ",
|
| 90 |
+
" ",
|
| 91 |
+
"\\begin{algorithm}[!b]",
|
| 92 |
+
" \\KwData{Desired review context $C_\\mathrm{input}$ (given as cleartext), NMT model}",
|
| 93 |
+
" \\KwResult{Generated review $out$ for input context $C_\\mathrm{input}$}",
|
| 94 |
+
"set $b=0.3$, $\\lambda=-5$, $\\alpha=\\frac{2}{3}$, $p_\\mathrm{typo}$, $p_\\mathrm{spell}$ \\\\",
|
| 95 |
+
"$\\log p \\leftarrow \\text{NMT.decode(NMT.encode(}C_\\mathrm{input}\\text{))}$ \\\\",
|
| 96 |
+
"out $\\leftarrow$ [~] \\\\",
|
| 97 |
+
"$i \\leftarrow 0$ \\\\",
|
| 98 |
+
"$\\log p \\leftarrow \\text{Augment}(\\log p$, $b$, $\\lambda$, $1$, $[~]$, 0)~~~~~~~~~~~~~~~ |~random penalty~\\\\",
|
| 99 |
+
"\\While{$i=0$ or $o_i$ not EOS}{",
|
| 100 |
+
"$\\log \\Tilde{p} \\leftarrow \\text{Augment}(\\log p$, $b$, $\\lambda$, $\\alpha$, $o_i$, $i$)~~~~~~~~~~~ |~start \\& memory penalty~\\\\",
|
| 101 |
+
"$o_i \\leftarrow$ \\text{NMT.beam}($\\log \\Tilde{p}$, out) \\\\",
|
| 102 |
+
"out.append($o_i$) \\\\",
|
| 103 |
+
"$i \\leftarrow i+1$",
|
| 104 |
+
"}\\text{return}~$\\text{Obfuscate}$(out,~$p_\\mathrm{typo}$,~$p_\\mathrm{spell}$)",
|
| 105 |
+
"\\caption{Generation of NMT-Fake* reviews.}",
|
| 106 |
+
"\\label{alg:base}",
|
| 107 |
+
"\\end{algorithm}",
|
| 108 |
+
" ",
|
| 109 |
+
"In this work, we describe how we succeeded in creating more diverse and less repetitive generated reviews, such as Example 3 in Figure~\\ref{fig:comparison}.",
|
| 110 |
+
"We outline pseudocode for our methodology of generating fake reviews in Algorithm~\\ref{alg:base}. There are several parameters in our algorithm.",
|
| 111 |
+
"The details of the algorithm will be shown later.",
|
| 112 |
+
"We modify the openNMT-py translation phase by changing log-probabilities before passing them to the beam search.",
|
| 113 |
+
"We notice that reviews generated with openNMT-py contain almost no language errors. As an optional post-processing step, we obfuscate reviews by introducing natural typos/misspellings randomly. In the next sections, we describe how we succeeded in generating more natural sentences from our NMT model, i.e. generating reviews like Example~3 instead of reviews like Example~2.",
|
| 114 |
+
" ",
|
| 115 |
+
"\\subsubsection{Variation in word content}",
|
| 116 |
+
" ",
|
| 117 |
+
"Example 2 in Figure~\\ref{fig:comparison} repeats commonly occurring words given for a specific context (e.g. \\textit{great, food, service, beer, selection, burger} for Example~1). Generic review generation can be avoided by decreasing probabilities (log-likelihoods \\cite{murphy2012machine}) of the generators LM, the decoder.",
|
| 118 |
+
"We constrain the generation of sentences by randomly \\emph{imposing penalties to words}.",
|
| 119 |
+
"We tried several forms of added randomness, and found that adding constant penalties to a \\emph{random subset} of the target words resulted in the most natural sentence flow. We call these penalties \\emph{Bernoulli penalties}, since the random variables are chosen as either 1 or 0 (on or off).",
|
| 120 |
+
" ",
|
| 121 |
+
" ",
|
| 122 |
+
"\\paragraph{Bernoulli penalties to language model}",
|
| 123 |
+
"To avoid generic sentences components, we augment the default language model $p(\\cdot)$ of the decoder by",
|
| 124 |
+
" ",
|
| 125 |
+
"\\begin{equation}",
|
| 126 |
+
"\\log \\Tilde{p}(t_k) = \\log p(t_k | t_i, \\dots, t_1) + \\lambda q,",
|
| 127 |
+
"\\end{equation}",
|
| 128 |
+
" ",
|
| 129 |
+
"where $q \\in R^{V}$ is a vector of Bernoulli-distributed random values that obtain values $1$ with probability $b$ and value $0$ with probability $1-b_i$, and $\\lambda < 0$. Parameter $b$ controls how much of the vocabulary is forgotten and $\\lambda$ is a soft penalty of including ``forgotten'' words in a review.",
|
| 130 |
+
"$\\lambda q_k$ emphasizes sentence forming with non-penalized words. The randomness is reset at the start of generating a new review.",
|
| 131 |
+
"Using Bernoulli penalties in the language model, we can ``forget'' a certain proportion of words and essentially ``force'' the creation of less typical sentences. We will test the effect of these two parameters, the Bernoulli probability $b$ and log-likelihood penalty of including ``forgotten'' words $\\lambda$, with a user study in Section~\\ref{sec:varying}.",
|
| 132 |
+
" ",
|
| 133 |
+
"\\paragraph{Start penalty}",
|
| 134 |
+
"We introduce start penalties to avoid generic sentence starts (e.g. ``Great food, great service''). Inspired by \\cite{li2016diversity}, we add a random start penalty $\\lambda s^\\mathrm{i}$, to our language model, which decreases monotonically for each generated token. We set $\\alpha \\leftarrow 0.66$ as it's effect decreases by 90\\% every 5 words generated.",
|
| 135 |
+
" ",
|
| 136 |
+
"\\paragraph{Penalty for reusing words}",
|
| 137 |
+
"Bernoulli penalties do not prevent excessive use of certain words in a sentence (such as \\textit{great} in Example~2).",
|
| 138 |
+
"To avoid excessive reuse of words, we included a memory penalty for previously used words in each translation.",
|
| 139 |
+
"Concretely, we add the penalty $\\lambda$ to each word that has been generated by the greedy search.",
|
| 140 |
+
" ",
|
| 141 |
+
"\\subsubsection{Improving sentence coherence}",
|
| 142 |
+
"\\label{sec:grammar}",
|
| 143 |
+
"We visually analyzed reviews after applying these penalties to our NMT model. While the models were clearly diverse, they were \\emph{incoherent}: the introduction of random penalties had degraded the grammaticality of the sentences. Amongst others, the use of punctuation was erratic, and pronouns were used semantically wrongly (e.g. \\emph{he}, \\emph{she} might be replaced, as could ``and''/``but''). To improve the authenticity of our reviews, we added several \\emph{grammar-based rules}.",
|
| 144 |
+
" ",
|
| 145 |
+
"English language has several classes of words which are important for the natural flow of sentences.",
|
| 146 |
+
"We built a list of common pronouns (e.g. I, them, our), conjunctions (e.g. and, thus, if), punctuation (e.g. ,/.,..), and apply only half memory penalties for these words. We found that this change made the reviews more coherent. The pseudocode for this and the previous step is shown in Algorithm~\\ref{alg:aug}.",
|
| 147 |
+
"The combined effect of grammar-based rules and LM augmentation is visible in Example~3, Figure~\\ref{fig:comparison}.",
|
| 148 |
+
" ",
|
| 149 |
+
"\\begin{algorithm}[!t]",
|
| 150 |
+
" \\KwData{Initial log LM $\\log p$, Bernoulli probability $b$, soft-penalty $\\lambda$, monotonic factor $\\alpha$, last generated token $o_i$, grammar rules set $G$}",
|
| 151 |
+
" \\KwResult{Augmented log LM $\\log \\Tilde{p}$}",
|
| 152 |
+
"\\begin{algorithmic}[1]",
|
| 153 |
+
"\\Procedure {Augment}{$\\log p$, $b$, $\\lambda$, $\\alpha$, $o_i$, $i$}{ \\\\",
|
| 154 |
+
"generate $P_{\\mathrm{1:N}} \\leftarrow Bernoulli(b)$~~~~~~~~~~~~~~~|~$\\text{One value} \\in \\{0,1\\}~\\text{per token}$~ \\\\",
|
| 155 |
+
"$I \\leftarrow P>0$ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|~Select positive indices~\\\\",
|
| 156 |
+
"$\\log \\Tilde{p} \\leftarrow$ $\\text{Discount}$($\\log p$, $I$, $\\lambda \\cdot \\alpha^i$,$G$) ~~~~~~ |~start penalty~\\\\",
|
| 157 |
+
"$\\log \\Tilde{p} \\leftarrow$ $\\text{Discount}$($\\log \\Tilde{p}$, $[o_i]$, $\\lambda$,$G$) ~~~~~~~~~ |~memory penalty~\\\\",
|
| 158 |
+
"\\textbf{return}~$\\log \\Tilde{p}$",
|
| 159 |
+
"}",
|
| 160 |
+
"\\EndProcedure",
|
| 161 |
+
"\\\\",
|
| 162 |
+
"\\Procedure {Discount}{$\\log p$, $I$, $\\lambda$, $G$}{",
|
| 163 |
+
"\\State{\\For{$i \\in I$}{",
|
| 164 |
+
"\\eIf{$o_i \\in G$}{",
|
| 165 |
+
"$\\log p_{i} \\leftarrow \\log p_{i} + \\lambda/2$",
|
| 166 |
+
"}{",
|
| 167 |
+
"$\\log p_{i} \\leftarrow \\log p_{i} + \\lambda$}",
|
| 168 |
+
"}\\textbf{return}~$\\log p$",
|
| 169 |
+
"\\EndProcedure",
|
| 170 |
+
"}}",
|
| 171 |
+
"\\end{algorithmic}",
|
| 172 |
+
"\\caption{Pseudocode for augmenting language model. }",
|
| 173 |
+
"\\label{alg:aug}",
|
| 174 |
+
"\\end{algorithm}",
|
| 175 |
+
" ",
|
| 176 |
+
"\\subsubsection{Human-like errors}",
|
| 177 |
+
"\\label{sec:obfuscation}",
|
| 178 |
+
"We notice that our NMT model produces reviews without grammar mistakes.",
|
| 179 |
+
"This is unlike real human writers, whose sentences contain two types of language mistakes 1) \\emph{typos} that are caused by mistakes in the human motoric input, and 2) \\emph{common spelling mistakes}.",
|
| 180 |
+
"We scraped a list of common English language spelling mistakes from Oxford dictionary\\footnote{\\url{https://en.oxforddictionaries.com/spelling/common-misspellings}} and created 80 rules for randomly \\emph{re-introducing spelling mistakes}.",
|
| 181 |
+
"Similarly, typos are randomly reintroduced based on the weighted edit distance\\footnote{\\url{https://pypi.python.org/pypi/weighted-levenshtein/0.1}}, such that typos resulting in real English words with small perturbations are emphasized.",
|
| 182 |
+
"We use autocorrection tools\\footnote{\\url{https://pypi.python.org/pypi/autocorrect/0.1.0}} for finding these words.",
|
| 183 |
+
"We call these augmentations \\emph{obfuscations}, since they aim to confound the reader to think a human has written them. We omit the pseudocode description for brevity.",
|
| 184 |
+
" ",
|
| 185 |
+
"\\subsection{Experiment: Varying generation parameters in our NMT model}",
|
| 186 |
+
"\\label{sec:varying}",
|
| 187 |
+
" ",
|
| 188 |
+
"Parameters $b$ and $\\lambda$ control different aspects in fake reviews.",
|
| 189 |
+
"We show six different examples of generated fake reviews in Table~\\ref{table:categories}.",
|
| 190 |
+
"Here, the largest differences occur with increasing values of $b$: visibly, the restaurant reviews become more extreme.",
|
| 191 |
+
"This occurs because a large portion of vocabulary is ``forgotten''. Reviews with $b \\geq 0.7$ contain more rare word combinations, e.g. ``!!!!!'' as punctuation, and they occasionally break grammaticality (''experience was awesome'').",
|
| 192 |
+
"Reviews with lower $b$ are more generic: they contain safe word combinations like ``Great place, good service'' that occur in many reviews. Parameter $\\lambda$'s is more subtle: it affects how random review starts are and to a degree, the discontinuation between statements within the review.",
|
| 193 |
+
"We conducted an Amazon Mechanical Turk (MTurk) survey in order to determine what kind of NMT-Fake reviews are convincing to native English speakers. We describe the survey and results in the next section.",
|
| 194 |
+
" ",
|
| 195 |
+
" ",
|
| 196 |
+
"\\begin{table}[!b]",
|
| 197 |
+
"\\caption{Six different parametrizations of our NMT reviews and one example for each. The context is ``5 P~.~F~.~Chang ' s Scottsdale AZ'' in all examples.}",
|
| 198 |
+
"\\begin{center}",
|
| 199 |
+
" \\begin{tabular}{ | l | l | }",
|
| 200 |
+
" \\hline",
|
| 201 |
+
" $(b, \\lambda)$ & Example review for context \\\\ \\hline",
|
| 202 |
+
" \\hline",
|
| 203 |
+
" $(0.3, -3)$ & I love this location! Great service, great food and the best drinks in Scottsdale. \\\\",
|
| 204 |
+
" & The staff is very friendly and always remembers u when we come in\\\\\\hline",
|
| 205 |
+
" $(0.3, -5)$ & Love love the food here! I always go for lunch. They have a great menu and \\\\",
|
| 206 |
+
" & they make it fresh to order. Great place, good service and nice staff\\\\\\hline",
|
| 207 |
+
" $(0.5, -4)$ & I love their chicken lettuce wraps and fried rice!! The service is good, they are\\\\",
|
| 208 |
+
" & always so polite. They have great happy hour specials and they have a lot\\\\",
|
| 209 |
+
" & of options.\\\\\\hline",
|
| 210 |
+
" $(0.7, -3)$ & Great place to go with friends! They always make sure your dining \\\\",
|
| 211 |
+
" & experience was awesome.\\\\ \\hline",
|
| 212 |
+
" $(0.7, -5)$ & Still haven't ordered an entree before but today we tried them once..\\\\",
|
| 213 |
+
" & both of us love this restaurant....\\\\\\hline",
|
| 214 |
+
" $(0.9, -4)$ & AMAZING!!!!! Food was awesome with excellent service. Loved the lettuce \\\\",
|
| 215 |
+
" & wraps. Great drinks and wine! Can't wait to go back so soon!!\\\\ \\hline",
|
| 216 |
+
" \\end{tabular}",
|
| 217 |
+
" \\label{table:categories}",
|
| 218 |
+
"\\end{center}",
|
| 219 |
+
"\\end{table}",
|
| 220 |
+
" ",
|
| 221 |
+
"\\subsubsection{MTurk study}",
|
| 222 |
+
"\\label{sec:amt}",
|
| 223 |
+
"We created 20 jobs, each with 100 questions, and requested master workers in MTurk to complete the jobs.",
|
| 224 |
+
"We randomly generated each survey for the participants. Each review had a 50\\% chance to be real or fake. The fake ones further were chosen among six (6) categories of fake reviews (Table~\\ref{table:categories}).",
|
| 225 |
+
"The restaurant and the city was given as contextual information to the participants. Our aim was to use this survey to understand how well English-speakers react to different parametrizations of NMT-Fake reviews.",
|
| 226 |
+
"Table~\\ref{table:amt_pop} in Appendix summarizes the statistics for respondents in the survey. All participants were native English speakers from America. The base rate (50\\%) was revealed to the participants prior to the study.",
|
| 227 |
+
" ",
|
| 228 |
+
"We first investigated overall detection of any NMT-Fake reviews (1,006 fake reviews and 994 real reviews). We found that the participants had big difficulties in detecting our fake reviews. In average, the reviews were detected with class-averaged \\emph{F-score of only 56\\%}, with 53\\% F-score for fake review detection and 59\\% F-score for real review detection. The results are very close to \\emph{random detection}, where precision, recall and F-score would each be 50\\%. Results are recorded in Table~\\ref{table:MTurk_super}. Overall, the fake review generation is very successful, since human detection rate across categories is close to random.",
|
| 229 |
+
" ",
|
| 230 |
+
"\\begin{table}[t]",
|
| 231 |
+
"\\caption{Effectiveness of Mechanical Turkers in distinguishing human-written reviews from fake reviews generated by our NMT model (all variants).}",
|
| 232 |
+
"\\begin{center}",
|
| 233 |
+
" \\begin{tabular}{ | c | c |c |c | c | }",
|
| 234 |
+
" \\hline",
|
| 235 |
+
" \\multicolumn{5}{|c|}{Classification report}",
|
| 236 |
+
" \\\\ \\hline",
|
| 237 |
+
" Review Type & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 238 |
+
" \\hline",
|
| 239 |
+
" Human & 55\\% & 63\\% & 59\\% & 994\\\\",
|
| 240 |
+
" NMT-Fake & 57\\% & 50\\% & 53\\% & 1006 \\\\",
|
| 241 |
+
" \\hline",
|
| 242 |
+
" \\end{tabular}",
|
| 243 |
+
" \\label{table:MTurk_super}",
|
| 244 |
+
"\\end{center}",
|
| 245 |
+
"\\end{table}",
|
| 246 |
+
" ",
|
| 247 |
+
"We noticed some variation in the detection of different fake review categories. The respondents in our MTurk survey had most difficulties recognizing reviews of category $(b=0.3, \\lambda=-5)$, where true positive rate was $40.4\\%$, while the true negative rate of the real class was $62.7\\%$. The precision were $16\\%$ and $86\\%$, respectively. The class-averaged F-score is $47.6\\%$, which is close to random. Detailed classification reports are shown in Table~\\ref{table:MTurk_sub} in Appendix. Our MTurk-study shows that \\emph{our NMT-Fake reviews pose a significant threat to review systems}, since \\emph{ordinary native English-speakers have very big difficulties in separating real reviews from fake reviews}. We use the review category $(b=0.3, \\lambda=-5)$ for future user tests in this paper, since MTurk participants had most difficulties detecting these reviews. We refer to this category as NMT-Fake* in this paper.",
|
| 248 |
+
" ",
|
| 249 |
+
"\\section{Evaluation}",
|
| 250 |
+
"\\graphicspath{ {figures/}}",
|
| 251 |
+
" ",
|
| 252 |
+
"We evaluate our fake reviews by first comparing them statistically to previously proposed types of fake reviews, and proceed with a user study with experienced participants. We demonstrate the statistical difference to existing fake review types \\cite{yao2017automated,mukherjee2013yelp,rayana2015collective} by training classifiers to detect previous types and investigate classification performance.",
|
| 253 |
+
" ",
|
| 254 |
+
"\\subsection{Replication of state-of-the-art model: LSTM}",
|
| 255 |
+
"\\label{sec:repl}",
|
| 256 |
+
" ",
|
| 257 |
+
"Yao et al. \\cite{yao2017automated} presented the current state-of-the-art generative model for fake reviews. The model is trained over the Yelp Challenge dataset using a two-layer character-based LSTM model.",
|
| 258 |
+
"We requested the authors of \\cite{yao2017automated} for access to their LSTM model or a fake review dataset generated by their model. Unfortunately they were not able to share either of these with us. We therefore replicated their model as closely as we could, based on their paper and e-mail correspondence\\footnote{We are committed to sharing our code with bonafide researchers for the sake of reproducibility.}.",
|
| 259 |
+
" ",
|
| 260 |
+
"We used the same graphics card (GeForce GTX) and trained using the same framework (torch-RNN in lua). We downloaded the reviews from Yelp Challenge and preprocessed the data to only contain printable ASCII characters, and filtered out non-restaurant reviews. We trained the model for approximately 72 hours. We post-processed the reviews using the customization methodology described in \\cite{yao2017automated} and email correspondence. We call fake reviews generated by this model LSTM-Fake reviews.",
|
| 261 |
+
" ",
|
| 262 |
+
"\\subsection{Similarity to existing fake reviews}",
|
| 263 |
+
"\\label{sec:automated}",
|
| 264 |
+
" ",
|
| 265 |
+
"We now want to understand how NMT-Fake* reviews compare to a) LSTM fake reviews and b) human-generated fake reviews. We do this by comparing the statistical similarity between these classes.",
|
| 266 |
+
" ",
|
| 267 |
+
"For `a' (Figure~\\ref{fig:lstm}), we use the Yelp Challenge dataset. We trained a classifier using 5,000 random reviews from the Yelp Challenge dataset (``human'') and 5,000 fake reviews generated by LSTM-Fake. Yao et al. \\cite{yao2017automated} found that character features are essential in identifying LSTM-Fake reviews. Consequently, we use character features (n-grams up to 3).",
|
| 268 |
+
" ",
|
| 269 |
+
"For `b' (Figure~\\ref{fig:shill}),we the ``Yelp Shills'' dataset (combination of YelpZip \\cite{mukherjee2013yelp}, YelpNYC \\cite{mukherjee2013yelp}, YelpChi \\cite{rayana2015collective}). This dataset labels entries that are identified as fraudulent by Yelp's filtering mechanism (''shill reviews'')\\footnote{Note that shill reviews are probably generated by human shills \\cite{zhao2017news}.}. The rest are treated as genuine reviews from human users (''genuine''). We use 100,000 reviews from each category to train a classifier. We use features from the commercial psychometric tool LIWC2015 \\cite{pennebaker2015development} to generated features.",
|
| 270 |
+
" ",
|
| 271 |
+
"In both cases, we use AdaBoost (with 200 shallow decision trees) for training. For testing each classifier, we use a held out test set of 1,000 reviews from both classes in each case. In addition, we test 1,000 NMT-Fake* reviews. Figures~\\ref{fig:lstm} and~\\ref{fig:shill} show the results. The classification threshold of 50\\% is marked with a dashed line.",
|
| 272 |
+
" ",
|
| 273 |
+
"\\begin{figure}",
|
| 274 |
+
" \\begin{subfigure}[b]{0.5\\columnwidth}",
|
| 275 |
+
" \\includegraphics[width=\\columnwidth]{figures/lstm.png}",
|
| 276 |
+
" \\caption{Human--LSTM reviews.}",
|
| 277 |
+
" \\label{fig:lstm}",
|
| 278 |
+
" \\end{subfigure}",
|
| 279 |
+
" \\begin{subfigure}[b]{0.5\\columnwidth}",
|
| 280 |
+
" \\includegraphics[width=\\columnwidth]{figures/distribution_shill.png}",
|
| 281 |
+
" \\caption{Genuine--Shill reviews.}",
|
| 282 |
+
" \\label{fig:shill}",
|
| 283 |
+
" \\end{subfigure}",
|
| 284 |
+
" \\caption{",
|
| 285 |
+
" Histogram comparison of NMT-Fake* reviews with LSTM-Fake reviews and human-generated (\\emph{genuine} and \\emph{shill}) reviews. Figure~\\ref{fig:lstm} shows that a classifier trained to distinguish ``human'' vs. LSTM-Fake cannot distinguish ``human'' vs NMT-Fake* reviews. Figure~\\ref{fig:shill} shows NMT-Fake* reviews are more similar to \\emph{genuine} reviews than \\emph{shill} reviews.",
|
| 286 |
+
" }",
|
| 287 |
+
" \\label{fig:statistical_similarity}",
|
| 288 |
+
"\\end{figure}",
|
| 289 |
+
" ",
|
| 290 |
+
"We can see that our new generated reviews do not share strong attributes with previous known categories of fake reviews. If anything, our fake reviews are more similar to genuine reviews than previous fake reviews. We thus conjecture that our NMT-Fake* fake reviews present a category of fake reviews that may go undetected on online review sites.",
|
| 291 |
+
" ",
|
| 292 |
+
" ",
|
| 293 |
+
"\\subsection{Comparative user study}",
|
| 294 |
+
"\\label{sec:comparison}",
|
| 295 |
+
"We wanted to evaluate the effectiveness of fake reviews againsttech-savvy users who understand and know to expect machine-generated fake reviews. We conducted a user study with 20 participants, all with computer science education and at least one university degree. Participant demographics are shown in Table~\\ref{table:amt_pop} in the Appendix. Each participant first attended a training session where they were asked to label reviews (fake and genuine) and could later compare them to the correct answers -- we call these participants \\emph{experienced participants}.",
|
| 296 |
+
"No personal data was collected during the user study.",
|
| 297 |
+
" ",
|
| 298 |
+
"Each person was given two randomly selected sets of 30 of reviews (a total of 60 reviews per person) with reviews containing 10 \\textendash 50 words each.",
|
| 299 |
+
"Each set contained 26 (87\\%) real reviews from Yelp and 4 (13\\%) machine-generated reviews,",
|
| 300 |
+
"numbers chosen based on suspicious review prevalence on Yelp~\\cite{mukherjee2013yelp,rayana2015collective}.",
|
| 301 |
+
"One set contained machine-generated reviews from one of the two models (NMT ($b=0.3, \\lambda=-5$) or LSTM),",
|
| 302 |
+
"and the other set reviews from the other in randomized order. The number of fake reviews was revealed to each participant in the study description. Each participant was requested to mark four (4) reviews as fake.",
|
| 303 |
+
" ",
|
| 304 |
+
"Each review targeted a real restaurant. A screenshot of that restaurant's Yelp page was shown to each participant prior to the study. Each participant evaluated reviews for one specific, randomly selected, restaurant. An example of the first page of the user study is shown in Figure~\\ref{fig:screenshot} in Appendix.",
|
| 305 |
+
" ",
|
| 306 |
+
"\\begin{figure}[!ht]",
|
| 307 |
+
"\\centering",
|
| 308 |
+
"\\includegraphics[width=.7\\columnwidth]{detection2.png}",
|
| 309 |
+
"\\caption{Violin plots of detection rate in comparative study. Mean and standard deviations for number of detected fakes are $0.8\\pm0.7$ for NMT-Fake* and $2.5\\pm1.0$ for LSTM-Fake. $n=20$. A sample of random detection is shown as comparison.}",
|
| 310 |
+
"\\label{fig:aalto}",
|
| 311 |
+
"\\end{figure}",
|
| 312 |
+
" ",
|
| 313 |
+
" ",
|
| 314 |
+
"Figure~\\ref{fig:aalto} shows the distribution of detected reviews of both types. A hypothetical random detector is shown for comparison.",
|
| 315 |
+
"NMT-Fake* reviews are significantly more difficult to detect for our experienced participants. In average, detection rate (recall) is $20\\%$ for NMT-Fake* reviews, compared to $61\\%$ for LSTM-based reviews.",
|
| 316 |
+
"The precision (and F-score) is the same as the recall in our study, since participants labeled 4 fakes in each set of 30 reviews \\cite{murphy2012machine}.",
|
| 317 |
+
"The distribution of the detection across participants is shown in Figure~\\ref{fig:aalto}. \\emph{The difference is statistically significant with confidence level $99\\%$} (Welch's t-test).",
|
| 318 |
+
"We compared the detection rate of NMT-Fake* reviews to a random detector, and find that \\emph{our participants detection rate of NMT-Fake* reviews is not statistically different from random predictions with 95\\% confidence level} (Welch's t-test).",
|
| 319 |
+
" ",
|
| 320 |
+
" ",
|
| 321 |
+
"\\section{Defenses}",
|
| 322 |
+
" ",
|
| 323 |
+
"\\label{sec:detection}",
|
| 324 |
+
" ",
|
| 325 |
+
"We developed an AdaBoost-based classifier to detect our new fake reviews, consisting of 200 shallow decision trees (depth 2). The features we used are recorded in Table~\\ref{table:features_adaboost} (Appendix).",
|
| 326 |
+
"We used word-level features based on spaCy-tokenization \\cite{honnibal-johnson:2015:EMNLP} and constructed n-gram representation of POS-tags and dependency tree tags. We added readability features from NLTK~\\cite{bird2004nltk}.",
|
| 327 |
+
" ",
|
| 328 |
+
"\\begin{figure}[ht]",
|
| 329 |
+
"\\centering",
|
| 330 |
+
"\\includegraphics[width=.7\\columnwidth]{obf_score_fair_2.png}",
|
| 331 |
+
"\\caption{",
|
| 332 |
+
"Adaboost-based classification of NMT-Fake and human-written reviews.",
|
| 333 |
+
"Effect of varying $b$ and $\\lambda$ in fake review generation.",
|
| 334 |
+
"The variant native speakers had most difficulties detecting is well detectable by AdaBoost (97\\%).}",
|
| 335 |
+
"\\label{fig:adaboost_matrix_b_lambda}",
|
| 336 |
+
"\\end{figure}",
|
| 337 |
+
" ",
|
| 338 |
+
" ",
|
| 339 |
+
"Figure~\\ref{fig:adaboost_matrix_b_lambda} shows our AdaBoost classifier's class-averaged F-score at detecting different kind of fake reviews. The classifier is very effective in detecting reviews that humans have difficulties detecting. For example, the fake reviews MTurk users had most difficulty detecting ($b=0.3, \\lambda=-5$) are detected with an excellent 97\\% F-score.",
|
| 340 |
+
"The most important features for the classification were counts for frequently occurring words in fake reviews (such as punctuation, pronouns, articles) as well as the readability feature ``Automated Readability Index''. We thus conclude that while NMT-Fake reviews are difficult to detect for humans, they can be well detected with the right tools.",
|
| 341 |
+
" ",
|
| 342 |
+
"\\section{Related Work}",
|
| 343 |
+
" ",
|
| 344 |
+
"Kumar and Shah~\\cite{kumar2018false} survey and categorize false information research. Automatically generated fake reviews are a form of \\emph{opinion-based false information}, where the creator of the review may influence reader's opinions or decisions.",
|
| 345 |
+
"Yao et al. \\cite{yao2017automated} presented their study on machine-generated fake reviews. Contrary to us, they investigated character-level language models, without specifying a specific context before generation. We leverage existing NMT tools to encode a specific context to the restaurant before generating reviews.",
|
| 346 |
+
"Supporting our study, Everett et al~\\cite{Everett2016Automated} found that security researchers were less likely to be fooled by Markov chain-generated Reddit comments compared to ordinary Internet users.",
|
| 347 |
+
" ",
|
| 348 |
+
"Diversification of NMT model outputs has been studied in \\cite{li2016diversity}. The authors proposed the use of a penalty to commonly occurring sentences (\\emph{n-grams}) in order to emphasize maximum mutual information-based generation.",
|
| 349 |
+
"The authors investigated the use of NMT models in chatbot systems.",
|
| 350 |
+
"We found that unigram penalties to random tokens (Algorithm~\\ref{alg:aug}) was easy to implement and produced sufficiently diverse responses.",
|
| 351 |
+
" ",
|
| 352 |
+
"\\section {Discussion and Future Work}",
|
| 353 |
+
" ",
|
| 354 |
+
"\\paragraph{What makes NMT-Fake* reviews difficult to detect?} First, NMT models allow the encoding of a relevant context for each review, which narrows down the possible choices of words that the model has to choose from. Our NMT model had a perplexity of approximately $25$, while the model of \\cite{yao2017automated} had a perplexity of approximately $90$ \\footnote{Personal communication with the authors}. Second, the beam search in NMT models narrows down choices to natural-looking sentences. Third, we observed that the NMT model produced \\emph{better structure} in the generated sentences (i.e. a more coherent story).",
|
| 355 |
+
" ",
|
| 356 |
+
"\\paragraph{Cost of generating reviews} With our setup, generating one review took less than one second. The cost of generation stems mainly from the overnight training. Assuming an electricity cost of 16 cents / kWh (California) and 8 hours of training, training the NMT model requires approximately 1.30 USD. This is a 90\\% reduction in time compared to the state-of-the-art \\cite{yao2017automated}. Furthermore, it is possible to generate both positive and negative reviews with the same model.",
|
| 357 |
+
" ",
|
| 358 |
+
"\\paragraph{Ease of customization} We experimented with inserting specific words into the text by increasing their log likelihoods in the beam search. We noticed that the success depended on the prevalence of the word in the training set. For example, adding a +5 to \\emph{Mike} in the log-likelihood resulted in approximately 10\\% prevalence of this word in the reviews. An attacker can therefore easily insert specific keywords to reviews, which can increase evasion probability.",
|
| 359 |
+
" ",
|
| 360 |
+
"\\paragraph{Ease of testing} Our diversification scheme is applicable during \\emph{generation phase}, and does not affect the training setup of the network in any way. Once the NMT model is obtained, it is easy to obtain several different variants of NMT-Fake reviews by varying parameters $b$ and $\\lambda$.",
|
| 361 |
+
" ",
|
| 362 |
+
" ",
|
| 363 |
+
" ",
|
| 364 |
+
"\\paragraph{Languages} The generation methodology is not per-se language-dependent. The requirement for successful generation is that sufficiently much data exists in the targeted language. However, our language model modifications require some knowledge of that target language's grammar to produce high-quality reviews.",
|
| 365 |
+
" ",
|
| 366 |
+
"\\paragraph{Generalizability of detection techniques} Currently, fake reviews are not universally detectable. Our results highlight that it is difficult to claim detection performance on unseen types of fake reviews (Section~\\ref{sec:automated}). We see this an open problem that deserves more attention in fake reviews research.",
|
| 367 |
+
" ",
|
| 368 |
+
"\\paragraph{Generalizability to other types of datasets} Our technique can be applied to any dataset, as long as there is sufficient training data for the NMT model. We used approximately 2.9 million reviews for this work.",
|
| 369 |
+
" ",
|
| 370 |
+
"\\section{Conclusion}",
|
| 371 |
+
" ",
|
| 372 |
+
"In this paper, we showed that neural machine translation models can be used to generate fake reviews that are very effective in deceiving even experienced, tech-savvy users.",
|
| 373 |
+
"This supports anecdotal evidence \\cite{national2017commission}.",
|
| 374 |
+
"Our technique is more effective than state-of-the-art \\cite{yao2017automated}.",
|
| 375 |
+
"We conclude that machine-aided fake review detection is necessary since human users are ineffective in identifying fake reviews.",
|
| 376 |
+
"We also showed that detectors trained using one type of fake reviews are not effective in identifying other types of fake reviews.",
|
| 377 |
+
"Robust detection of fake reviews is thus still an open problem.",
|
| 378 |
+
" ",
|
| 379 |
+
" ",
|
| 380 |
+
"\\section*{Acknowledgments}",
|
| 381 |
+
"We thank Tommi Gr\\\"{o}ndahl for assistance in planning user studies and the",
|
| 382 |
+
"participants of the user study for their time and feedback. We also thank",
|
| 383 |
+
"Luiza Sayfullina for comments that improved the manuscript.",
|
| 384 |
+
"We thank the authors of \\cite{yao2017automated} for answering questions about",
|
| 385 |
+
"their work.",
|
| 386 |
+
" ",
|
| 387 |
+
" ",
|
| 388 |
+
"\\bibliographystyle{splncs}",
|
| 389 |
+
"\\begin{thebibliography}{10}",
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| 390 |
+
" ",
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| 391 |
+
"\\bibitem{yao2017automated}",
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+
"Yao, Y., Viswanath, B., Cryan, J., Zheng, H., Zhao, B.Y.:",
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+
"\\newblock Automated crowdturfing attacks and defenses in online review systems.",
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+
"\\newblock In: Proceedings of the 2017 ACM SIGSAC Conference on Computer and",
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+
" Communications Security, ACM (2017)",
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+
" ",
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+
"\\bibitem{murphy2012machine}",
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+
"Murphy, K.:",
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| 399 |
+
"\\newblock Machine learning: a probabilistic approach.",
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| 400 |
+
"\\newblock Massachusetts Institute of Technology (2012)",
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+
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+
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+
"Yelp:",
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+
"\\newblock {Yelp Challenge Dataset} (2013)",
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+
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+
"\\bibitem{mukherjee2013yelp}",
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"\\newblock Speech and language processing. Volume~3.",
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"\\newblock arXiv preprint arXiv:1412.6980 (2014)",
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| 463 |
+
" ",
|
| 464 |
+
"\\bibitem{cho2014learning}",
|
| 465 |
+
"Cho, K., van Merrienboer, B., Gulcehre, C., Bahdanau, D., Bougares, F.,",
|
| 466 |
+
" Schwenk, H., Bengio, Y.:",
|
| 467 |
+
"\\newblock Learning phrase representations using rnn encoder--decoder for",
|
| 468 |
+
" statistical machine translation.",
|
| 469 |
+
"\\newblock In: Proceedings of the 2014 Conference on Empirical Methods in",
|
| 470 |
+
" Natural Language Processing (EMNLP). (2014)",
|
| 471 |
+
" ",
|
| 472 |
+
"\\bibitem{klein2017opennmt}",
|
| 473 |
+
"Klein, G., Kim, Y., Deng, Y., Senellart, J., Rush, A.:",
|
| 474 |
+
"\\newblock Opennmt: Open-source toolkit for neural machine translation.",
|
| 475 |
+
"\\newblock Proceedings of ACL, System Demonstrations (2017)",
|
| 476 |
+
" ",
|
| 477 |
+
"\\bibitem{wu2016google}",
|
| 478 |
+
"Wu, Y., Schuster, M., Chen, Z., Le, Q.V., Norouzi, M., Macherey, W., Krikun,",
|
| 479 |
+
" M., Cao, Y., Gao, Q., Macherey, K., et~al.:",
|
| 480 |
+
"\\newblock Google's neural machine translation system: Bridging the gap between",
|
| 481 |
+
" human and machine translation.",
|
| 482 |
+
"\\newblock arXiv preprint arXiv:1609.08144 (2016)",
|
| 483 |
+
" ",
|
| 484 |
+
"\\bibitem{mei2017coherent}",
|
| 485 |
+
"Mei, H., Bansal, M., Walter, M.R.:",
|
| 486 |
+
"\\newblock Coherent dialogue with attention-based language models.",
|
| 487 |
+
"\\newblock In: AAAI. (2017) 3252--3258",
|
| 488 |
+
" ",
|
| 489 |
+
"\\bibitem{li2016diversity}",
|
| 490 |
+
"Li, J., Galley, M., Brockett, C., Gao, J., Dolan, B.:",
|
| 491 |
+
"\\newblock A diversity-promoting objective function for neural conversation",
|
| 492 |
+
" models.",
|
| 493 |
+
"\\newblock In: Proceedings of NAACL-HLT. (2016)",
|
| 494 |
+
" ",
|
| 495 |
+
"\\bibitem{rubin2006assessing}",
|
| 496 |
+
"Rubin, V.L., Liddy, E.D.:",
|
| 497 |
+
"\\newblock Assessing credibility of weblogs.",
|
| 498 |
+
"\\newblock In: AAAI Spring Symposium: Computational Approaches to Analyzing",
|
| 499 |
+
" Weblogs. (2006)",
|
| 500 |
+
" ",
|
| 501 |
+
"\\bibitem{zhao2017news}",
|
| 502 |
+
"news.com.au:",
|
| 503 |
+
"\\newblock {The potential of AI generated 'crowdturfing' could undermine online",
|
| 504 |
+
" reviews and dramatically erode public trust} URL:",
|
| 505 |
+
" \\url{http://www.news.com.au/technology/online/security/the-potential-of-ai-generated-crowdturfing-could-undermine-online-reviews-and-dramatically-erode-public-trust/news-story/e1c84ad909b586f8a08238d5f80b6982}.",
|
| 506 |
+
" ",
|
| 507 |
+
"\\bibitem{pennebaker2015development}",
|
| 508 |
+
"Pennebaker, J.W., Boyd, R.L., Jordan, K., Blackburn, K.:",
|
| 509 |
+
"\\newblock {The development and psychometric properties of LIWC2015}.",
|
| 510 |
+
"\\newblock Technical report (2015)",
|
| 511 |
+
" ",
|
| 512 |
+
"\\bibitem{honnibal-johnson:2015:EMNLP}",
|
| 513 |
+
"Honnibal, M., Johnson, M.:",
|
| 514 |
+
"\\newblock An improved non-monotonic transition system for dependency parsing.",
|
| 515 |
+
"\\newblock In: Proceedings of the 2015 Conference on Empirical Methods in",
|
| 516 |
+
" Natural Language Processing (EMNLP), ACM (2015)",
|
| 517 |
+
" ",
|
| 518 |
+
"\\bibitem{bird2004nltk}",
|
| 519 |
+
"Bird, S., Loper, E.:",
|
| 520 |
+
"\\newblock {NLTK: the natural language toolkit}.",
|
| 521 |
+
"\\newblock In: Proceedings of the ACL 2004 on Interactive poster and",
|
| 522 |
+
" demonstration sessions, Association for Computational Linguistics (2004)",
|
| 523 |
+
" ",
|
| 524 |
+
"\\bibitem{kumar2018false}",
|
| 525 |
+
"Kumar, S., Shah, N.:",
|
| 526 |
+
"\\newblock False information on web and social media: A survey.",
|
| 527 |
+
"\\newblock arXiv preprint arXiv:1804.08559 (2018)",
|
| 528 |
+
" ",
|
| 529 |
+
"\\bibitem{Everett2016Automated}",
|
| 530 |
+
"Everett, R.M., Nurse, J.R.C., Erola, A.:",
|
| 531 |
+
"\\newblock The anatomy of online deception: What makes automated text",
|
| 532 |
+
" convincing?",
|
| 533 |
+
"\\newblock In: Proceedings of the 31st Annual ACM Symposium on Applied",
|
| 534 |
+
" Computing. SAC '16, ACM (2016)",
|
| 535 |
+
" ",
|
| 536 |
+
"\\end{thebibliography}",
|
| 537 |
+
" ",
|
| 538 |
+
" ",
|
| 539 |
+
" ",
|
| 540 |
+
"\\section*{Appendix}",
|
| 541 |
+
" ",
|
| 542 |
+
"We present basic demographics of our MTurk study and the comparative study with experienced users in Table~\\ref{table:amt_pop}.",
|
| 543 |
+
" ",
|
| 544 |
+
"\\begin{table}",
|
| 545 |
+
"\\caption{User study statistics.}",
|
| 546 |
+
"\\begin{center}",
|
| 547 |
+
" \\begin{tabular}{ | l | c | c | }",
|
| 548 |
+
" \\hline",
|
| 549 |
+
" Quality & Mechanical Turk users & Experienced users\\\\",
|
| 550 |
+
" \\hline",
|
| 551 |
+
" Native English Speaker & Yes (20) & Yes (1) No (19) \\\\",
|
| 552 |
+
" Fluent in English & Yes (20) & Yes (20) \\\\",
|
| 553 |
+
" Age & 21-40 (17) 41-60 (3) & 21-25 (8) 26-30 (7) 31-35 (4) 41-45 (1)\\\\",
|
| 554 |
+
" Gender & Male (14) Female (6) & Male (17) Female (3)\\\\",
|
| 555 |
+
" Highest Education & High School (10) Bachelor (10) & Bachelor (9) Master (6) Ph.D. (5) \\\\",
|
| 556 |
+
" \\hline",
|
| 557 |
+
" \\end{tabular}",
|
| 558 |
+
" \\label{table:amt_pop}",
|
| 559 |
+
"\\end{center}",
|
| 560 |
+
"\\end{table}",
|
| 561 |
+
" ",
|
| 562 |
+
" ",
|
| 563 |
+
"Table~\\ref{table:openNMT-py_commands} shows a listing of the openNMT-py commands we used to create our NMT model and to generate fake reviews.",
|
| 564 |
+
" ",
|
| 565 |
+
"\\begin{table}[t]",
|
| 566 |
+
"\\caption{Listing of used openNMT-py commands.}",
|
| 567 |
+
"\\begin{center}",
|
| 568 |
+
" \\begin{tabular}{ | l | l | }",
|
| 569 |
+
" \\hline",
|
| 570 |
+
" Phase & Bash command \\\\",
|
| 571 |
+
" \\hline",
|
| 572 |
+
" Preprocessing & \\begin{lstlisting}[language=bash]",
|
| 573 |
+
"python preprocess.py -train_src context-train.txt",
|
| 574 |
+
"-train_tgt reviews-train.txt -valid_src context-val.txt",
|
| 575 |
+
"-valid_tgt reviews-val.txt -save_data model",
|
| 576 |
+
"-lower -tgt_words_min_frequency 10",
|
| 577 |
+
"\\end{lstlisting}",
|
| 578 |
+
" \\\\ & \\\\",
|
| 579 |
+
" Training & \\begin{lstlisting}[language=bash]",
|
| 580 |
+
"python train.py -data model -save_model model -epochs 8",
|
| 581 |
+
"-gpuid 0 -learning_rate_decay 0.5 -optim adam",
|
| 582 |
+
"-learning_rate 0.001 -start_decay_at 3\\end{lstlisting}",
|
| 583 |
+
" \\\\ & \\\\",
|
| 584 |
+
" Generation & \\begin{lstlisting}[language=bash]",
|
| 585 |
+
"python translate.py -model model_acc_35.54_ppl_25.68_e8.pt",
|
| 586 |
+
"-src context-tst.txt -output pred-e8.txt -replace_unk",
|
| 587 |
+
"-verbose -max_length 50 -gpu 0",
|
| 588 |
+
" \\end{lstlisting} \\\\",
|
| 589 |
+
" \\hline",
|
| 590 |
+
" \\end{tabular}",
|
| 591 |
+
" \\label{table:openNMT-py_commands}",
|
| 592 |
+
"\\end{center}",
|
| 593 |
+
"\\end{table}",
|
| 594 |
+
" ",
|
| 595 |
+
" ",
|
| 596 |
+
"Table~\\ref{table:MTurk_sub} shows the classification performance of Amazon Mechanical Turkers, separated across different categories of NMT-Fake reviews. The category with best performance ($b=0.3, \\lambda=-5$) is denoted as NMT-Fake*.",
|
| 597 |
+
" ",
|
| 598 |
+
"\\begin{table}[b]",
|
| 599 |
+
"\\caption{MTurk study subclass classification reports. Classes are imbalanced in ratio 1:6. Random predictions are $p_\\mathrm{human} = 86\\%$ and $p_\\mathrm{machine} = 14\\%$, with $r_\\mathrm{human} = r_\\mathrm{machine} = 50\\%$. Class-averaged F-scores for random predictions are $42\\%$.}",
|
| 600 |
+
"\\begin{center}",
|
| 601 |
+
" \\begin{tabular}{ | c || c |c |c | c | }",
|
| 602 |
+
" \\hline",
|
| 603 |
+
" $(b=0.3, \\lambda = -3)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 604 |
+
" Human & 89\\% & 63\\% & 73\\% & 994\\\\",
|
| 605 |
+
" NMT-Fake & 15\\% & 45\\% & 22\\% & 146 \\\\",
|
| 606 |
+
" \\hline",
|
| 607 |
+
" \\hline",
|
| 608 |
+
" $(b=0.3, \\lambda = -5)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 609 |
+
" Human & 86\\% & 63\\% & 73\\% & 994\\\\",
|
| 610 |
+
" NMT-Fake* & 16\\% & 40\\% & 23\\% & 171 \\\\",
|
| 611 |
+
" \\hline",
|
| 612 |
+
" \\hline",
|
| 613 |
+
" $(b=0.5, \\lambda = -4)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 614 |
+
" Human & 88\\% & 63\\% & 73\\% & 994\\\\",
|
| 615 |
+
" NMT-Fake & 21\\% & 55\\% & 30\\% & 181 \\\\",
|
| 616 |
+
" \\hline",
|
| 617 |
+
" \\hline",
|
| 618 |
+
" $(b=0.7, \\lambda = -3)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 619 |
+
" Human & 88\\% & 63\\% & 73\\% & 994\\\\",
|
| 620 |
+
" NMT-Fake & 19\\% & 50\\% & 27\\% & 170 \\\\",
|
| 621 |
+
" \\hline",
|
| 622 |
+
" \\hline",
|
| 623 |
+
" $(b=0.7, \\lambda = -5)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 624 |
+
" Human & 89\\% & 63\\% & 74\\% & 994\\\\",
|
| 625 |
+
" NMT-Fake & 21\\% & 57\\% & 31\\% & 174 \\\\",
|
| 626 |
+
" \\hline",
|
| 627 |
+
" \\hline",
|
| 628 |
+
" $(b=0.9, \\lambda = -4)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 629 |
+
" Human & 88\\% & 63\\% & 73\\% & 994\\\\",
|
| 630 |
+
" NMT-Fake & 18\\% & 50\\% & 27\\% & 164 \\\\",
|
| 631 |
+
" \\hline",
|
| 632 |
+
" \\end{tabular}",
|
| 633 |
+
" \\label{table:MTurk_sub}",
|
| 634 |
+
"\\end{center}",
|
| 635 |
+
"\\end{table}",
|
| 636 |
+
" ",
|
| 637 |
+
"Figure~\\ref{fig:screenshot} shows screenshots of the first two pages of our user study with experienced participants.",
|
| 638 |
+
" ",
|
| 639 |
+
"\\begin{figure}[ht]",
|
| 640 |
+
"\\centering",
|
| 641 |
+
"\\includegraphics[width=1.\\columnwidth]{figures/screenshot_7-3.png}",
|
| 642 |
+
"\\caption{",
|
| 643 |
+
"Screenshots of the first two pages in the user study. Example 1 is a NMT-Fake* review, the rest are human-written.",
|
| 644 |
+
"}",
|
| 645 |
+
"\\label{fig:screenshot}",
|
| 646 |
+
"\\end{figure}",
|
| 647 |
+
" ",
|
| 648 |
+
"Table~\\ref{table:features_adaboost} shows the features used to detect NMT-Fake reviews using the AdaBoost classifier.",
|
| 649 |
+
" ",
|
| 650 |
+
"\\begin{table}",
|
| 651 |
+
"\\caption{Features used in NMT-Fake review detector.}",
|
| 652 |
+
"\\begin{center}",
|
| 653 |
+
" \\begin{tabular}{ | l | c | }",
|
| 654 |
+
" \\hline",
|
| 655 |
+
" Feature type & Number of features \\\\ \\hline",
|
| 656 |
+
" \\hline",
|
| 657 |
+
" Readability features & 13 \\\\ \\hline",
|
| 658 |
+
" Unique POS tags & $~20$ \\\\ \\hline",
|
| 659 |
+
" Word unigrams & 22,831 \\\\ \\hline",
|
| 660 |
+
" 1/2/3/4-grams of simple part-of-speech tags & 54,240 \\\\ \\hline",
|
| 661 |
+
" 1/2/3-grams of detailed part-of-speech tags & 112,944 \\\\ \\hline",
|
| 662 |
+
" 1/2/3-grams of syntactic dependency tags & 93,195 \\\\ \\hline",
|
| 663 |
+
" \\end{tabular}",
|
| 664 |
+
" \\label{table:features_adaboost}",
|
| 665 |
+
"\\end{center}",
|
| 666 |
+
"\\end{table}",
|
| 667 |
+
" ",
|
| 668 |
+
"\\end{document}",
|
| 669 |
+
""
|
| 670 |
+
]
|
| 671 |
+
]
|
| 672 |
+
}
|
| 673 |
+
```
|
qasper-0034/instruction.md
ADDED
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|
| 1 |
+
Name of Paper: Stay On-Topic: Generating Context-specific Fake Restaurant Reviews
|
| 2 |
+
|
| 3 |
+
Question: Do they use a pretrained NMT model to help generating reviews?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Background",
|
| 12 |
+
"System Model",
|
| 13 |
+
"Attack Model",
|
| 14 |
+
"Generative Model"
|
| 15 |
+
],
|
| 16 |
+
"paragraphs": [
|
| 17 |
+
[
|
| 18 |
+
"Automatically generated fake reviews have only recently become natural enough to fool human readers. Yao et al. BIBREF0 use a deep neural network (a so-called 2-layer LSTM BIBREF1 ) to generate fake reviews, and concluded that these fake reviews look sufficiently genuine to fool native English speakers. They train their model using real restaurant reviews from yelp.com BIBREF2 . Once trained, the model is used to generate reviews character-by-character. Due to the generation methodology, it cannot be easily targeted for a specific context (meaningful side information). Consequently, the review generation process may stray off-topic. For instance, when generating a review for a Japanese restaurant in Las Vegas, the review generation process may include references to an Italian restaurant in Baltimore. The authors of BIBREF0 apply a post-processing step (customization), which replaces food-related words with more suitable ones (sampled from the targeted restaurant). The word replacement strategy has drawbacks: it can miss certain words and replace others independent of their surrounding words, which may alert savvy readers. As an example: when we applied the customization technique described in BIBREF0 to a review for a Japanese restaurant it changed the snippet garlic knots for breakfast with garlic knots for sushi).",
|
| 19 |
+
"We propose a methodology based on neural machine translation (NMT) that improves the generation process by defining a context for the each generated fake review. Our context is a clear-text sequence of: the review rating, restaurant name, city, state and food tags (e.g. Japanese, Italian). We show that our technique generates review that stay on topic. We can instantiate our basic technique into several variants. We vet them on Amazon Mechanical Turk and find that native English speakers are very poor at recognizing our fake generated reviews. For one variant, the participants' performance is close to random: the class-averaged F-score of detection is INLINEFORM0 (whereas random would be INLINEFORM1 given the 1:6 imbalance in the test). Via a user study with experienced, highly educated participants, we compare this variant (which we will henceforth refer to as NMT-Fake* reviews) with fake reviews generated using the char-LSTM-based technique from BIBREF0 .",
|
| 20 |
+
"We demonstrate that NMT-Fake* reviews constitute a new category of fake reviews that cannot be detected by classifiers trained only using previously known categories of fake reviews BIBREF0 , BIBREF3 , BIBREF4 . Therefore, NMT-Fake* reviews may go undetected in existing online review sites. To meet this challenge, we develop an effective classifier that detects NMT-Fake* reviews effectively (97% F-score). Our main contributions are:"
|
| 21 |
+
],
|
| 22 |
+
[
|
| 23 |
+
"Fake reviews User-generated content BIBREF5 is an integral part of the contemporary user experience on the web. Sites like tripadvisor.com, yelp.com and Google Play use user-written reviews to provide rich information that helps other users choose where to spend money and time. User reviews are used for rating services or products, and for providing qualitative opinions. User reviews and ratings may be used to rank services in recommendations. Ratings have an affect on the outwards appearance. Already 8 years ago, researchers estimated that a one-star rating increase affects the business revenue by 5 \u2013 9% on yelp.com BIBREF6 .",
|
| 24 |
+
"Due to monetary impact of user-generated content, some businesses have relied on so-called crowd-turfing agents BIBREF7 that promise to deliver positive ratings written by workers to a customer in exchange for a monetary compensation. Crowd-turfing ethics are complicated. For example, Amazon community guidelines prohibit buying content relating to promotions, but the act of writing fabricated content is not considered illegal, nor is matching workers to customers BIBREF8 . Year 2015, approximately 20% of online reviews on yelp.com were suspected of being fake BIBREF9 .",
|
| 25 |
+
"Nowadays, user-generated review sites like yelp.com use filters and fraudulent review detection techniques. These factors have resulted in an increase in the requirements of crowd-turfed reviews provided to review sites, which in turn has led to an increase in the cost of high-quality review. Due to the cost increase, researchers hypothesize the existence of neural network-generated fake reviews. These neural-network-based fake reviews are statistically different from human-written fake reviews, and are not caught by classifiers trained on these BIBREF0 .",
|
| 26 |
+
"Detecting fake reviews can either be done on an individual level or as a system-wide detection tool (i.e. regulation). Detecting fake online content on a personal level requires knowledge and skills in critical reading. In 2017, the National Literacy Trust assessed that young people in the UK do not have the skillset to differentiate fake news from real news BIBREF10 . For example, 20% of children that use online news sites in age group 12-15 believe that all information on news sites are true.",
|
| 27 |
+
"Neural Networks Neural networks are function compositions that map input data through INLINEFORM0 subsequent layers: DISPLAYFORM0 ",
|
| 28 |
+
"where the functions INLINEFORM0 are typically non-linear and chosen by experts partly for known good performance on datasets and partly for simplicity of computational evaluation. Language models (LMs) BIBREF11 are generative probability distributions that assign probabilities to sequences of tokens ( INLINEFORM1 ): DISPLAYFORM0 ",
|
| 29 |
+
"such that the language model can be used to predict how likely a specific token at time step INLINEFORM0 is, based on the INLINEFORM1 previous tokens. Tokens are typically either words or characters.",
|
| 30 |
+
"For decades, deep neural networks were thought to be computationally too difficult to train. However, advances in optimization, hardware and the availability of frameworks have shown otherwise BIBREF1 , BIBREF12 . Neural language models (NLMs) have been one of the promising application areas. NLMs are typically various forms of recurrent neural networks (RNNs), which pass through the data sequentially and maintain a memory representation of the past tokens with a hidden context vector. There are many RNN architectures that focus on different ways of updating and maintaining context vectors: Long Short-Term Memory units (LSTM) and Gated Recurrent Units (GRUs) are perhaps most popular. Neural LMs have been used for free-form text generation. In certain application areas, the quality has been high enough to sometimes fool human readers BIBREF0 . Encoder-decoder (seq2seq) models BIBREF13 are architectures of stacked RNNs, which have the ability to generate output sequences based on input sequences. The encoder network reads in a sequence of tokens, and passes it to a decoder network (a LM). In contrast to simpler NLMs, encoder-decoder networks have the ability to use additional context for generating text, which enables more accurate generation of text. Encoder-decoder models are integral in Neural Machine Translation (NMT) BIBREF14 , where the task is to translate a source text from one language to another language. NMT models additionally use beam search strategies to heuristically search the set of possible translations. Training datasets are parallel corpora; large sets of paired sentences in the source and target languages. The application of NMT techniques for online machine translation has significantly improved the quality of translations, bringing it closer to human performance BIBREF15 .",
|
| 31 |
+
"Neural machine translation models are efficient at mapping one expression to another (one-to-one mapping). Researchers have evaluated these models for conversation generation BIBREF16 , with mixed results. Some researchers attribute poor performance to the use of the negative log likelihood cost function during training, which emphasizes generation of high-confidence phrases rather than diverse phrases BIBREF17 . The results are often generic text, which lacks variation. Li et al. have suggested various augmentations to this, among others suppressing typical responses in the decoder language model to promote response diversity BIBREF17 ."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"We discuss the attack model, our generative machine learning method and controlling the generative process in this section."
|
| 35 |
+
],
|
| 36 |
+
[
|
| 37 |
+
"Wang et al. BIBREF7 described a model of crowd-turfing attacks consisting of three entities: customers who desire to have fake reviews for a particular target (e.g. their restaurant) on a particular platform (e.g. Yelp), agents who offer fake review services to customers, and workers who are orchestrated by the agent to compose and post fake reviews.",
|
| 38 |
+
"Automated crowd-turfing attacks (ACA) replace workers by a generative model. This has several benefits including better economy and scalability (human workers are more expensive and slower) and reduced detectability (agent can better control the rate at which fake reviews are generated and posted).",
|
| 39 |
+
"We assume that the agent has access to public reviews on the review platform, by which it can train its generative model. We also assume that it is easy for the agent to create a large number of accounts on the review platform so that account-based detection or rate-limiting techniques are ineffective against fake reviews.",
|
| 40 |
+
"The quality of the generative model plays a crucial role in the attack. Yao et al. BIBREF0 propose the use of a character-based LSTM as base for generative model. LSTMs are not conditioned to generate reviews for a specific target BIBREF1 , and may mix-up concepts from different contexts during free-form generation. Mixing contextually separate words is one of the key criteria that humans use to identify fake reviews. These may result in violations of known indicators for fake content BIBREF18 . For example, the review content may not match prior expectations nor the information need that the reader has. We improve the attack model by considering a more capable generative model that produces more appropriate reviews: a neural machine translation (NMT) model."
|
| 41 |
+
],
|
| 42 |
+
[
|
| 43 |
+
"We propose the use of NMT models for fake review generation. The method has several benefits: 1) the ability to learn how to associate context (keywords) to reviews, 2) fast training time, and 3) a high-degree of customization during production time, e.g. introduction of specific waiter or food items names into reviews.",
|
| 44 |
+
"NMT models are constructions of stacked recurrent neural networks (RNNs). They include an encoder network and a decoder network, which are jointly optimized to produce a translation of one sequence to another. The encoder rolls over the input data in sequence and produces one INLINEFORM0 -dimensional context vector representation for the sentence. The decoder then generates output sequences based on the embedding vector and an attention module, which is taught to associate output words with certain input words. The generation typically continues until a specific EOS (end of sentence) token is encountered. The review length can be controlled in many ways, e.g. by setting the probability of generating the EOS token to zero until the required length is reached.",
|
| 45 |
+
"NMT models often also include a beam search BIBREF14 , which generates several hypotheses and chooses the best ones amongst them. In our work, we use the greedy beam search technique. We forgo the use of additional beam searches as we found that the quality of the output was already adequate and the translation phase time consumption increases linearly for each beam used.",
|
| 46 |
+
"We use the Yelp Challenge dataset BIBREF2 for our fake review generation. The dataset (Aug 2017) contains 2.9 million 1 \u20135 star restaurant reviews. We treat all reviews as genuine human-written reviews for the purpose of this work, since wide-scale deployment of machine-generated review attacks are not yet reported (Sep 2017) BIBREF19 . As preprocessing, we remove non-printable (non-ASCII) characters and excessive white-space. We separate punctuation from words. We reserve 15,000 reviews for validation and 3,000 for testing, and the rest we use for training. NMT models require a parallel corpus of source and target sentences, i.e. a large set of (source, target)-pairs. We set up a parallel corpus by constructing (context, review)-pairs from the dataset. Next, we describe how we created our input context.",
|
| 47 |
+
"The Yelp Challenge dataset includes metadata about restaurants, including their names, food tags, cities and states these restaurants are located in. For each restaurant review, we fetch this metadata and use it as our input context in the NMT model. The corresponding restaurant review is similarly set as the target sentence. This method produced 2.9 million pairs of sentences in our parallel corpus. We show one example of the parallel training corpus in Example 1 below:",
|
| 48 |
+
"5 Public House Las Vegas NV Gastropubs Restaurants > Excellent",
|
| 49 |
+
"food and service . Pricey , but well worth it . I would recommend",
|
| 50 |
+
"the bone marrow and sampler platter for appetizers . \\end{verbatim}",
|
| 51 |
+
" ",
|
| 52 |
+
" ",
|
| 53 |
+
"\\noindent The order {\\textbf{[rating name city state tags]}} is kept constant.",
|
| 54 |
+
"Training the model conditions it to associate certain sequences of words in the input sentence with others in the output.",
|
| 55 |
+
" ",
|
| 56 |
+
"\\subsubsection{Training Settings}",
|
| 57 |
+
" ",
|
| 58 |
+
"We train our NMT model on a commodity PC with a i7-4790k CPU (4.00GHz), with 32GB RAM and one NVidia GeForce GTX 980 GPU. Our system can process approximately 1,300 \\textendash 1,500 source tokens/s and approximately 5,730 \\textendash 5,830 output tokens/s. Training one epoch takes in average 72 minutes. The model is trained for 8 epochs, i.e. over night. We call fake review generated by this model \\emph{NMT-Fake reviews}. We only need to train one model to produce reviews of different ratings.",
|
| 59 |
+
"We use the training settings: adam optimizer \\cite{kingma2014adam} with the suggested learning rate 0.001 \\cite{klein2017opennmt}. For most parts, parameters are at their default values. Notably, the maximum sentence length of input and output is 50 tokens by default.",
|
| 60 |
+
"We leverage the framework openNMT-py \\cite{klein2017opennmt} to teach the our NMT model.",
|
| 61 |
+
"We list used openNMT-py commands in Appendix Table~\\ref{table:openNMT-py_commands}.",
|
| 62 |
+
" ",
|
| 63 |
+
"\\begin{figure}[t]",
|
| 64 |
+
"\\begin{center}",
|
| 65 |
+
" \\begin{tabular}{ | l | }",
|
| 66 |
+
" \\hline",
|
| 67 |
+
"Example 2. Greedy NMT \\\\",
|
| 68 |
+
"Great food, \\underline{great} service, \\underline{great} \\textit{\\textit{beer selection}}. I had the \\textit{Gastropubs burger} and it",
|
| 69 |
+
"\\\\",
|
| 70 |
+
"was delicious. The \\underline{\\textit{beer selection}} was also \\underline{great}. \\\\",
|
| 71 |
+
"\\\\",
|
| 72 |
+
"Example 3. NMT-Fake* \\\\",
|
| 73 |
+
"I love this restaurant. Great food, great service. It's \\textit{a little pricy} but worth\\\\",
|
| 74 |
+
"it for the \\textit{quality} of the \\textit{beer} and atmosphere you can see in \\textit{Vegas}",
|
| 75 |
+
"\\\\",
|
| 76 |
+
" \\hline",
|
| 77 |
+
" \\end{tabular}",
|
| 78 |
+
" \\label{table:output_comparison}",
|
| 79 |
+
"\\end{center}",
|
| 80 |
+
"\\caption{Na\\\"{i}ve text generation with NMT vs. generation using our NTM model. Repetitive patterns are \\underline{underlined}. Contextual words are \\emph{italicized}. Both examples here are generated based on the context given in Example~1.}",
|
| 81 |
+
"\\label{fig:comparison}",
|
| 82 |
+
"\\end{figure}",
|
| 83 |
+
" ",
|
| 84 |
+
"\\subsection{Controlling generation of fake reviews}",
|
| 85 |
+
"\\label{sec:generating}",
|
| 86 |
+
" ",
|
| 87 |
+
"Greedy NMT beam searches are practical in many NMT cases. However, the results are simply repetitive, when naively applied to fake review generation (See Example~2 in Figure~\\ref{fig:comparison}).",
|
| 88 |
+
"The NMT model produces many \\emph{high-confidence} word predictions, which are repetitive and obviously fake. We calculated that in fact, 43\\% of the generated sentences started with the phrase ``Great food''. The lack of diversity in greedy use of NMTs for text generation is clear.",
|
| 89 |
+
" ",
|
| 90 |
+
" ",
|
| 91 |
+
"\\begin{algorithm}[!b]",
|
| 92 |
+
" \\KwData{Desired review context $C_\\mathrm{input}$ (given as cleartext), NMT model}",
|
| 93 |
+
" \\KwResult{Generated review $out$ for input context $C_\\mathrm{input}$}",
|
| 94 |
+
"set $b=0.3$, $\\lambda=-5$, $\\alpha=\\frac{2}{3}$, $p_\\mathrm{typo}$, $p_\\mathrm{spell}$ \\\\",
|
| 95 |
+
"$\\log p \\leftarrow \\text{NMT.decode(NMT.encode(}C_\\mathrm{input}\\text{))}$ \\\\",
|
| 96 |
+
"out $\\leftarrow$ [~] \\\\",
|
| 97 |
+
"$i \\leftarrow 0$ \\\\",
|
| 98 |
+
"$\\log p \\leftarrow \\text{Augment}(\\log p$, $b$, $\\lambda$, $1$, $[~]$, 0)~~~~~~~~~~~~~~~ |~random penalty~\\\\",
|
| 99 |
+
"\\While{$i=0$ or $o_i$ not EOS}{",
|
| 100 |
+
"$\\log \\Tilde{p} \\leftarrow \\text{Augment}(\\log p$, $b$, $\\lambda$, $\\alpha$, $o_i$, $i$)~~~~~~~~~~~ |~start \\& memory penalty~\\\\",
|
| 101 |
+
"$o_i \\leftarrow$ \\text{NMT.beam}($\\log \\Tilde{p}$, out) \\\\",
|
| 102 |
+
"out.append($o_i$) \\\\",
|
| 103 |
+
"$i \\leftarrow i+1$",
|
| 104 |
+
"}\\text{return}~$\\text{Obfuscate}$(out,~$p_\\mathrm{typo}$,~$p_\\mathrm{spell}$)",
|
| 105 |
+
"\\caption{Generation of NMT-Fake* reviews.}",
|
| 106 |
+
"\\label{alg:base}",
|
| 107 |
+
"\\end{algorithm}",
|
| 108 |
+
" ",
|
| 109 |
+
"In this work, we describe how we succeeded in creating more diverse and less repetitive generated reviews, such as Example 3 in Figure~\\ref{fig:comparison}.",
|
| 110 |
+
"We outline pseudocode for our methodology of generating fake reviews in Algorithm~\\ref{alg:base}. There are several parameters in our algorithm.",
|
| 111 |
+
"The details of the algorithm will be shown later.",
|
| 112 |
+
"We modify the openNMT-py translation phase by changing log-probabilities before passing them to the beam search.",
|
| 113 |
+
"We notice that reviews generated with openNMT-py contain almost no language errors. As an optional post-processing step, we obfuscate reviews by introducing natural typos/misspellings randomly. In the next sections, we describe how we succeeded in generating more natural sentences from our NMT model, i.e. generating reviews like Example~3 instead of reviews like Example~2.",
|
| 114 |
+
" ",
|
| 115 |
+
"\\subsubsection{Variation in word content}",
|
| 116 |
+
" ",
|
| 117 |
+
"Example 2 in Figure~\\ref{fig:comparison} repeats commonly occurring words given for a specific context (e.g. \\textit{great, food, service, beer, selection, burger} for Example~1). Generic review generation can be avoided by decreasing probabilities (log-likelihoods \\cite{murphy2012machine}) of the generators LM, the decoder.",
|
| 118 |
+
"We constrain the generation of sentences by randomly \\emph{imposing penalties to words}.",
|
| 119 |
+
"We tried several forms of added randomness, and found that adding constant penalties to a \\emph{random subset} of the target words resulted in the most natural sentence flow. We call these penalties \\emph{Bernoulli penalties}, since the random variables are chosen as either 1 or 0 (on or off).",
|
| 120 |
+
" ",
|
| 121 |
+
" ",
|
| 122 |
+
"\\paragraph{Bernoulli penalties to language model}",
|
| 123 |
+
"To avoid generic sentences components, we augment the default language model $p(\\cdot)$ of the decoder by",
|
| 124 |
+
" ",
|
| 125 |
+
"\\begin{equation}",
|
| 126 |
+
"\\log \\Tilde{p}(t_k) = \\log p(t_k | t_i, \\dots, t_1) + \\lambda q,",
|
| 127 |
+
"\\end{equation}",
|
| 128 |
+
" ",
|
| 129 |
+
"where $q \\in R^{V}$ is a vector of Bernoulli-distributed random values that obtain values $1$ with probability $b$ and value $0$ with probability $1-b_i$, and $\\lambda < 0$. Parameter $b$ controls how much of the vocabulary is forgotten and $\\lambda$ is a soft penalty of including ``forgotten'' words in a review.",
|
| 130 |
+
"$\\lambda q_k$ emphasizes sentence forming with non-penalized words. The randomness is reset at the start of generating a new review.",
|
| 131 |
+
"Using Bernoulli penalties in the language model, we can ``forget'' a certain proportion of words and essentially ``force'' the creation of less typical sentences. We will test the effect of these two parameters, the Bernoulli probability $b$ and log-likelihood penalty of including ``forgotten'' words $\\lambda$, with a user study in Section~\\ref{sec:varying}.",
|
| 132 |
+
" ",
|
| 133 |
+
"\\paragraph{Start penalty}",
|
| 134 |
+
"We introduce start penalties to avoid generic sentence starts (e.g. ``Great food, great service''). Inspired by \\cite{li2016diversity}, we add a random start penalty $\\lambda s^\\mathrm{i}$, to our language model, which decreases monotonically for each generated token. We set $\\alpha \\leftarrow 0.66$ as it's effect decreases by 90\\% every 5 words generated.",
|
| 135 |
+
" ",
|
| 136 |
+
"\\paragraph{Penalty for reusing words}",
|
| 137 |
+
"Bernoulli penalties do not prevent excessive use of certain words in a sentence (such as \\textit{great} in Example~2).",
|
| 138 |
+
"To avoid excessive reuse of words, we included a memory penalty for previously used words in each translation.",
|
| 139 |
+
"Concretely, we add the penalty $\\lambda$ to each word that has been generated by the greedy search.",
|
| 140 |
+
" ",
|
| 141 |
+
"\\subsubsection{Improving sentence coherence}",
|
| 142 |
+
"\\label{sec:grammar}",
|
| 143 |
+
"We visually analyzed reviews after applying these penalties to our NMT model. While the models were clearly diverse, they were \\emph{incoherent}: the introduction of random penalties had degraded the grammaticality of the sentences. Amongst others, the use of punctuation was erratic, and pronouns were used semantically wrongly (e.g. \\emph{he}, \\emph{she} might be replaced, as could ``and''/``but''). To improve the authenticity of our reviews, we added several \\emph{grammar-based rules}.",
|
| 144 |
+
" ",
|
| 145 |
+
"English language has several classes of words which are important for the natural flow of sentences.",
|
| 146 |
+
"We built a list of common pronouns (e.g. I, them, our), conjunctions (e.g. and, thus, if), punctuation (e.g. ,/.,..), and apply only half memory penalties for these words. We found that this change made the reviews more coherent. The pseudocode for this and the previous step is shown in Algorithm~\\ref{alg:aug}.",
|
| 147 |
+
"The combined effect of grammar-based rules and LM augmentation is visible in Example~3, Figure~\\ref{fig:comparison}.",
|
| 148 |
+
" ",
|
| 149 |
+
"\\begin{algorithm}[!t]",
|
| 150 |
+
" \\KwData{Initial log LM $\\log p$, Bernoulli probability $b$, soft-penalty $\\lambda$, monotonic factor $\\alpha$, last generated token $o_i$, grammar rules set $G$}",
|
| 151 |
+
" \\KwResult{Augmented log LM $\\log \\Tilde{p}$}",
|
| 152 |
+
"\\begin{algorithmic}[1]",
|
| 153 |
+
"\\Procedure {Augment}{$\\log p$, $b$, $\\lambda$, $\\alpha$, $o_i$, $i$}{ \\\\",
|
| 154 |
+
"generate $P_{\\mathrm{1:N}} \\leftarrow Bernoulli(b)$~~~~~~~~~~~~~~~|~$\\text{One value} \\in \\{0,1\\}~\\text{per token}$~ \\\\",
|
| 155 |
+
"$I \\leftarrow P>0$ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|~Select positive indices~\\\\",
|
| 156 |
+
"$\\log \\Tilde{p} \\leftarrow$ $\\text{Discount}$($\\log p$, $I$, $\\lambda \\cdot \\alpha^i$,$G$) ~~~~~~ |~start penalty~\\\\",
|
| 157 |
+
"$\\log \\Tilde{p} \\leftarrow$ $\\text{Discount}$($\\log \\Tilde{p}$, $[o_i]$, $\\lambda$,$G$) ~~~~~~~~~ |~memory penalty~\\\\",
|
| 158 |
+
"\\textbf{return}~$\\log \\Tilde{p}$",
|
| 159 |
+
"}",
|
| 160 |
+
"\\EndProcedure",
|
| 161 |
+
"\\\\",
|
| 162 |
+
"\\Procedure {Discount}{$\\log p$, $I$, $\\lambda$, $G$}{",
|
| 163 |
+
"\\State{\\For{$i \\in I$}{",
|
| 164 |
+
"\\eIf{$o_i \\in G$}{",
|
| 165 |
+
"$\\log p_{i} \\leftarrow \\log p_{i} + \\lambda/2$",
|
| 166 |
+
"}{",
|
| 167 |
+
"$\\log p_{i} \\leftarrow \\log p_{i} + \\lambda$}",
|
| 168 |
+
"}\\textbf{return}~$\\log p$",
|
| 169 |
+
"\\EndProcedure",
|
| 170 |
+
"}}",
|
| 171 |
+
"\\end{algorithmic}",
|
| 172 |
+
"\\caption{Pseudocode for augmenting language model. }",
|
| 173 |
+
"\\label{alg:aug}",
|
| 174 |
+
"\\end{algorithm}",
|
| 175 |
+
" ",
|
| 176 |
+
"\\subsubsection{Human-like errors}",
|
| 177 |
+
"\\label{sec:obfuscation}",
|
| 178 |
+
"We notice that our NMT model produces reviews without grammar mistakes.",
|
| 179 |
+
"This is unlike real human writers, whose sentences contain two types of language mistakes 1) \\emph{typos} that are caused by mistakes in the human motoric input, and 2) \\emph{common spelling mistakes}.",
|
| 180 |
+
"We scraped a list of common English language spelling mistakes from Oxford dictionary\\footnote{\\url{https://en.oxforddictionaries.com/spelling/common-misspellings}} and created 80 rules for randomly \\emph{re-introducing spelling mistakes}.",
|
| 181 |
+
"Similarly, typos are randomly reintroduced based on the weighted edit distance\\footnote{\\url{https://pypi.python.org/pypi/weighted-levenshtein/0.1}}, such that typos resulting in real English words with small perturbations are emphasized.",
|
| 182 |
+
"We use autocorrection tools\\footnote{\\url{https://pypi.python.org/pypi/autocorrect/0.1.0}} for finding these words.",
|
| 183 |
+
"We call these augmentations \\emph{obfuscations}, since they aim to confound the reader to think a human has written them. We omit the pseudocode description for brevity.",
|
| 184 |
+
" ",
|
| 185 |
+
"\\subsection{Experiment: Varying generation parameters in our NMT model}",
|
| 186 |
+
"\\label{sec:varying}",
|
| 187 |
+
" ",
|
| 188 |
+
"Parameters $b$ and $\\lambda$ control different aspects in fake reviews.",
|
| 189 |
+
"We show six different examples of generated fake reviews in Table~\\ref{table:categories}.",
|
| 190 |
+
"Here, the largest differences occur with increasing values of $b$: visibly, the restaurant reviews become more extreme.",
|
| 191 |
+
"This occurs because a large portion of vocabulary is ``forgotten''. Reviews with $b \\geq 0.7$ contain more rare word combinations, e.g. ``!!!!!'' as punctuation, and they occasionally break grammaticality (''experience was awesome'').",
|
| 192 |
+
"Reviews with lower $b$ are more generic: they contain safe word combinations like ``Great place, good service'' that occur in many reviews. Parameter $\\lambda$'s is more subtle: it affects how random review starts are and to a degree, the discontinuation between statements within the review.",
|
| 193 |
+
"We conducted an Amazon Mechanical Turk (MTurk) survey in order to determine what kind of NMT-Fake reviews are convincing to native English speakers. We describe the survey and results in the next section.",
|
| 194 |
+
" ",
|
| 195 |
+
" ",
|
| 196 |
+
"\\begin{table}[!b]",
|
| 197 |
+
"\\caption{Six different parametrizations of our NMT reviews and one example for each. The context is ``5 P~.~F~.~Chang ' s Scottsdale AZ'' in all examples.}",
|
| 198 |
+
"\\begin{center}",
|
| 199 |
+
" \\begin{tabular}{ | l | l | }",
|
| 200 |
+
" \\hline",
|
| 201 |
+
" $(b, \\lambda)$ & Example review for context \\\\ \\hline",
|
| 202 |
+
" \\hline",
|
| 203 |
+
" $(0.3, -3)$ & I love this location! Great service, great food and the best drinks in Scottsdale. \\\\",
|
| 204 |
+
" & The staff is very friendly and always remembers u when we come in\\\\\\hline",
|
| 205 |
+
" $(0.3, -5)$ & Love love the food here! I always go for lunch. They have a great menu and \\\\",
|
| 206 |
+
" & they make it fresh to order. Great place, good service and nice staff\\\\\\hline",
|
| 207 |
+
" $(0.5, -4)$ & I love their chicken lettuce wraps and fried rice!! The service is good, they are\\\\",
|
| 208 |
+
" & always so polite. They have great happy hour specials and they have a lot\\\\",
|
| 209 |
+
" & of options.\\\\\\hline",
|
| 210 |
+
" $(0.7, -3)$ & Great place to go with friends! They always make sure your dining \\\\",
|
| 211 |
+
" & experience was awesome.\\\\ \\hline",
|
| 212 |
+
" $(0.7, -5)$ & Still haven't ordered an entree before but today we tried them once..\\\\",
|
| 213 |
+
" & both of us love this restaurant....\\\\\\hline",
|
| 214 |
+
" $(0.9, -4)$ & AMAZING!!!!! Food was awesome with excellent service. Loved the lettuce \\\\",
|
| 215 |
+
" & wraps. Great drinks and wine! Can't wait to go back so soon!!\\\\ \\hline",
|
| 216 |
+
" \\end{tabular}",
|
| 217 |
+
" \\label{table:categories}",
|
| 218 |
+
"\\end{center}",
|
| 219 |
+
"\\end{table}",
|
| 220 |
+
" ",
|
| 221 |
+
"\\subsubsection{MTurk study}",
|
| 222 |
+
"\\label{sec:amt}",
|
| 223 |
+
"We created 20 jobs, each with 100 questions, and requested master workers in MTurk to complete the jobs.",
|
| 224 |
+
"We randomly generated each survey for the participants. Each review had a 50\\% chance to be real or fake. The fake ones further were chosen among six (6) categories of fake reviews (Table~\\ref{table:categories}).",
|
| 225 |
+
"The restaurant and the city was given as contextual information to the participants. Our aim was to use this survey to understand how well English-speakers react to different parametrizations of NMT-Fake reviews.",
|
| 226 |
+
"Table~\\ref{table:amt_pop} in Appendix summarizes the statistics for respondents in the survey. All participants were native English speakers from America. The base rate (50\\%) was revealed to the participants prior to the study.",
|
| 227 |
+
" ",
|
| 228 |
+
"We first investigated overall detection of any NMT-Fake reviews (1,006 fake reviews and 994 real reviews). We found that the participants had big difficulties in detecting our fake reviews. In average, the reviews were detected with class-averaged \\emph{F-score of only 56\\%}, with 53\\% F-score for fake review detection and 59\\% F-score for real review detection. The results are very close to \\emph{random detection}, where precision, recall and F-score would each be 50\\%. Results are recorded in Table~\\ref{table:MTurk_super}. Overall, the fake review generation is very successful, since human detection rate across categories is close to random.",
|
| 229 |
+
" ",
|
| 230 |
+
"\\begin{table}[t]",
|
| 231 |
+
"\\caption{Effectiveness of Mechanical Turkers in distinguishing human-written reviews from fake reviews generated by our NMT model (all variants).}",
|
| 232 |
+
"\\begin{center}",
|
| 233 |
+
" \\begin{tabular}{ | c | c |c |c | c | }",
|
| 234 |
+
" \\hline",
|
| 235 |
+
" \\multicolumn{5}{|c|}{Classification report}",
|
| 236 |
+
" \\\\ \\hline",
|
| 237 |
+
" Review Type & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 238 |
+
" \\hline",
|
| 239 |
+
" Human & 55\\% & 63\\% & 59\\% & 994\\\\",
|
| 240 |
+
" NMT-Fake & 57\\% & 50\\% & 53\\% & 1006 \\\\",
|
| 241 |
+
" \\hline",
|
| 242 |
+
" \\end{tabular}",
|
| 243 |
+
" \\label{table:MTurk_super}",
|
| 244 |
+
"\\end{center}",
|
| 245 |
+
"\\end{table}",
|
| 246 |
+
" ",
|
| 247 |
+
"We noticed some variation in the detection of different fake review categories. The respondents in our MTurk survey had most difficulties recognizing reviews of category $(b=0.3, \\lambda=-5)$, where true positive rate was $40.4\\%$, while the true negative rate of the real class was $62.7\\%$. The precision were $16\\%$ and $86\\%$, respectively. The class-averaged F-score is $47.6\\%$, which is close to random. Detailed classification reports are shown in Table~\\ref{table:MTurk_sub} in Appendix. Our MTurk-study shows that \\emph{our NMT-Fake reviews pose a significant threat to review systems}, since \\emph{ordinary native English-speakers have very big difficulties in separating real reviews from fake reviews}. We use the review category $(b=0.3, \\lambda=-5)$ for future user tests in this paper, since MTurk participants had most difficulties detecting these reviews. We refer to this category as NMT-Fake* in this paper.",
|
| 248 |
+
" ",
|
| 249 |
+
"\\section{Evaluation}",
|
| 250 |
+
"\\graphicspath{ {figures/}}",
|
| 251 |
+
" ",
|
| 252 |
+
"We evaluate our fake reviews by first comparing them statistically to previously proposed types of fake reviews, and proceed with a user study with experienced participants. We demonstrate the statistical difference to existing fake review types \\cite{yao2017automated,mukherjee2013yelp,rayana2015collective} by training classifiers to detect previous types and investigate classification performance.",
|
| 253 |
+
" ",
|
| 254 |
+
"\\subsection{Replication of state-of-the-art model: LSTM}",
|
| 255 |
+
"\\label{sec:repl}",
|
| 256 |
+
" ",
|
| 257 |
+
"Yao et al. \\cite{yao2017automated} presented the current state-of-the-art generative model for fake reviews. The model is trained over the Yelp Challenge dataset using a two-layer character-based LSTM model.",
|
| 258 |
+
"We requested the authors of \\cite{yao2017automated} for access to their LSTM model or a fake review dataset generated by their model. Unfortunately they were not able to share either of these with us. We therefore replicated their model as closely as we could, based on their paper and e-mail correspondence\\footnote{We are committed to sharing our code with bonafide researchers for the sake of reproducibility.}.",
|
| 259 |
+
" ",
|
| 260 |
+
"We used the same graphics card (GeForce GTX) and trained using the same framework (torch-RNN in lua). We downloaded the reviews from Yelp Challenge and preprocessed the data to only contain printable ASCII characters, and filtered out non-restaurant reviews. We trained the model for approximately 72 hours. We post-processed the reviews using the customization methodology described in \\cite{yao2017automated} and email correspondence. We call fake reviews generated by this model LSTM-Fake reviews.",
|
| 261 |
+
" ",
|
| 262 |
+
"\\subsection{Similarity to existing fake reviews}",
|
| 263 |
+
"\\label{sec:automated}",
|
| 264 |
+
" ",
|
| 265 |
+
"We now want to understand how NMT-Fake* reviews compare to a) LSTM fake reviews and b) human-generated fake reviews. We do this by comparing the statistical similarity between these classes.",
|
| 266 |
+
" ",
|
| 267 |
+
"For `a' (Figure~\\ref{fig:lstm}), we use the Yelp Challenge dataset. We trained a classifier using 5,000 random reviews from the Yelp Challenge dataset (``human'') and 5,000 fake reviews generated by LSTM-Fake. Yao et al. \\cite{yao2017automated} found that character features are essential in identifying LSTM-Fake reviews. Consequently, we use character features (n-grams up to 3).",
|
| 268 |
+
" ",
|
| 269 |
+
"For `b' (Figure~\\ref{fig:shill}),we the ``Yelp Shills'' dataset (combination of YelpZip \\cite{mukherjee2013yelp}, YelpNYC \\cite{mukherjee2013yelp}, YelpChi \\cite{rayana2015collective}). This dataset labels entries that are identified as fraudulent by Yelp's filtering mechanism (''shill reviews'')\\footnote{Note that shill reviews are probably generated by human shills \\cite{zhao2017news}.}. The rest are treated as genuine reviews from human users (''genuine''). We use 100,000 reviews from each category to train a classifier. We use features from the commercial psychometric tool LIWC2015 \\cite{pennebaker2015development} to generated features.",
|
| 270 |
+
" ",
|
| 271 |
+
"In both cases, we use AdaBoost (with 200 shallow decision trees) for training. For testing each classifier, we use a held out test set of 1,000 reviews from both classes in each case. In addition, we test 1,000 NMT-Fake* reviews. Figures~\\ref{fig:lstm} and~\\ref{fig:shill} show the results. The classification threshold of 50\\% is marked with a dashed line.",
|
| 272 |
+
" ",
|
| 273 |
+
"\\begin{figure}",
|
| 274 |
+
" \\begin{subfigure}[b]{0.5\\columnwidth}",
|
| 275 |
+
" \\includegraphics[width=\\columnwidth]{figures/lstm.png}",
|
| 276 |
+
" \\caption{Human--LSTM reviews.}",
|
| 277 |
+
" \\label{fig:lstm}",
|
| 278 |
+
" \\end{subfigure}",
|
| 279 |
+
" \\begin{subfigure}[b]{0.5\\columnwidth}",
|
| 280 |
+
" \\includegraphics[width=\\columnwidth]{figures/distribution_shill.png}",
|
| 281 |
+
" \\caption{Genuine--Shill reviews.}",
|
| 282 |
+
" \\label{fig:shill}",
|
| 283 |
+
" \\end{subfigure}",
|
| 284 |
+
" \\caption{",
|
| 285 |
+
" Histogram comparison of NMT-Fake* reviews with LSTM-Fake reviews and human-generated (\\emph{genuine} and \\emph{shill}) reviews. Figure~\\ref{fig:lstm} shows that a classifier trained to distinguish ``human'' vs. LSTM-Fake cannot distinguish ``human'' vs NMT-Fake* reviews. Figure~\\ref{fig:shill} shows NMT-Fake* reviews are more similar to \\emph{genuine} reviews than \\emph{shill} reviews.",
|
| 286 |
+
" }",
|
| 287 |
+
" \\label{fig:statistical_similarity}",
|
| 288 |
+
"\\end{figure}",
|
| 289 |
+
" ",
|
| 290 |
+
"We can see that our new generated reviews do not share strong attributes with previous known categories of fake reviews. If anything, our fake reviews are more similar to genuine reviews than previous fake reviews. We thus conjecture that our NMT-Fake* fake reviews present a category of fake reviews that may go undetected on online review sites.",
|
| 291 |
+
" ",
|
| 292 |
+
" ",
|
| 293 |
+
"\\subsection{Comparative user study}",
|
| 294 |
+
"\\label{sec:comparison}",
|
| 295 |
+
"We wanted to evaluate the effectiveness of fake reviews againsttech-savvy users who understand and know to expect machine-generated fake reviews. We conducted a user study with 20 participants, all with computer science education and at least one university degree. Participant demographics are shown in Table~\\ref{table:amt_pop} in the Appendix. Each participant first attended a training session where they were asked to label reviews (fake and genuine) and could later compare them to the correct answers -- we call these participants \\emph{experienced participants}.",
|
| 296 |
+
"No personal data was collected during the user study.",
|
| 297 |
+
" ",
|
| 298 |
+
"Each person was given two randomly selected sets of 30 of reviews (a total of 60 reviews per person) with reviews containing 10 \\textendash 50 words each.",
|
| 299 |
+
"Each set contained 26 (87\\%) real reviews from Yelp and 4 (13\\%) machine-generated reviews,",
|
| 300 |
+
"numbers chosen based on suspicious review prevalence on Yelp~\\cite{mukherjee2013yelp,rayana2015collective}.",
|
| 301 |
+
"One set contained machine-generated reviews from one of the two models (NMT ($b=0.3, \\lambda=-5$) or LSTM),",
|
| 302 |
+
"and the other set reviews from the other in randomized order. The number of fake reviews was revealed to each participant in the study description. Each participant was requested to mark four (4) reviews as fake.",
|
| 303 |
+
" ",
|
| 304 |
+
"Each review targeted a real restaurant. A screenshot of that restaurant's Yelp page was shown to each participant prior to the study. Each participant evaluated reviews for one specific, randomly selected, restaurant. An example of the first page of the user study is shown in Figure~\\ref{fig:screenshot} in Appendix.",
|
| 305 |
+
" ",
|
| 306 |
+
"\\begin{figure}[!ht]",
|
| 307 |
+
"\\centering",
|
| 308 |
+
"\\includegraphics[width=.7\\columnwidth]{detection2.png}",
|
| 309 |
+
"\\caption{Violin plots of detection rate in comparative study. Mean and standard deviations for number of detected fakes are $0.8\\pm0.7$ for NMT-Fake* and $2.5\\pm1.0$ for LSTM-Fake. $n=20$. A sample of random detection is shown as comparison.}",
|
| 310 |
+
"\\label{fig:aalto}",
|
| 311 |
+
"\\end{figure}",
|
| 312 |
+
" ",
|
| 313 |
+
" ",
|
| 314 |
+
"Figure~\\ref{fig:aalto} shows the distribution of detected reviews of both types. A hypothetical random detector is shown for comparison.",
|
| 315 |
+
"NMT-Fake* reviews are significantly more difficult to detect for our experienced participants. In average, detection rate (recall) is $20\\%$ for NMT-Fake* reviews, compared to $61\\%$ for LSTM-based reviews.",
|
| 316 |
+
"The precision (and F-score) is the same as the recall in our study, since participants labeled 4 fakes in each set of 30 reviews \\cite{murphy2012machine}.",
|
| 317 |
+
"The distribution of the detection across participants is shown in Figure~\\ref{fig:aalto}. \\emph{The difference is statistically significant with confidence level $99\\%$} (Welch's t-test).",
|
| 318 |
+
"We compared the detection rate of NMT-Fake* reviews to a random detector, and find that \\emph{our participants detection rate of NMT-Fake* reviews is not statistically different from random predictions with 95\\% confidence level} (Welch's t-test).",
|
| 319 |
+
" ",
|
| 320 |
+
" ",
|
| 321 |
+
"\\section{Defenses}",
|
| 322 |
+
" ",
|
| 323 |
+
"\\label{sec:detection}",
|
| 324 |
+
" ",
|
| 325 |
+
"We developed an AdaBoost-based classifier to detect our new fake reviews, consisting of 200 shallow decision trees (depth 2). The features we used are recorded in Table~\\ref{table:features_adaboost} (Appendix).",
|
| 326 |
+
"We used word-level features based on spaCy-tokenization \\cite{honnibal-johnson:2015:EMNLP} and constructed n-gram representation of POS-tags and dependency tree tags. We added readability features from NLTK~\\cite{bird2004nltk}.",
|
| 327 |
+
" ",
|
| 328 |
+
"\\begin{figure}[ht]",
|
| 329 |
+
"\\centering",
|
| 330 |
+
"\\includegraphics[width=.7\\columnwidth]{obf_score_fair_2.png}",
|
| 331 |
+
"\\caption{",
|
| 332 |
+
"Adaboost-based classification of NMT-Fake and human-written reviews.",
|
| 333 |
+
"Effect of varying $b$ and $\\lambda$ in fake review generation.",
|
| 334 |
+
"The variant native speakers had most difficulties detecting is well detectable by AdaBoost (97\\%).}",
|
| 335 |
+
"\\label{fig:adaboost_matrix_b_lambda}",
|
| 336 |
+
"\\end{figure}",
|
| 337 |
+
" ",
|
| 338 |
+
" ",
|
| 339 |
+
"Figure~\\ref{fig:adaboost_matrix_b_lambda} shows our AdaBoost classifier's class-averaged F-score at detecting different kind of fake reviews. The classifier is very effective in detecting reviews that humans have difficulties detecting. For example, the fake reviews MTurk users had most difficulty detecting ($b=0.3, \\lambda=-5$) are detected with an excellent 97\\% F-score.",
|
| 340 |
+
"The most important features for the classification were counts for frequently occurring words in fake reviews (such as punctuation, pronouns, articles) as well as the readability feature ``Automated Readability Index''. We thus conclude that while NMT-Fake reviews are difficult to detect for humans, they can be well detected with the right tools.",
|
| 341 |
+
" ",
|
| 342 |
+
"\\section{Related Work}",
|
| 343 |
+
" ",
|
| 344 |
+
"Kumar and Shah~\\cite{kumar2018false} survey and categorize false information research. Automatically generated fake reviews are a form of \\emph{opinion-based false information}, where the creator of the review may influence reader's opinions or decisions.",
|
| 345 |
+
"Yao et al. \\cite{yao2017automated} presented their study on machine-generated fake reviews. Contrary to us, they investigated character-level language models, without specifying a specific context before generation. We leverage existing NMT tools to encode a specific context to the restaurant before generating reviews.",
|
| 346 |
+
"Supporting our study, Everett et al~\\cite{Everett2016Automated} found that security researchers were less likely to be fooled by Markov chain-generated Reddit comments compared to ordinary Internet users.",
|
| 347 |
+
" ",
|
| 348 |
+
"Diversification of NMT model outputs has been studied in \\cite{li2016diversity}. The authors proposed the use of a penalty to commonly occurring sentences (\\emph{n-grams}) in order to emphasize maximum mutual information-based generation.",
|
| 349 |
+
"The authors investigated the use of NMT models in chatbot systems.",
|
| 350 |
+
"We found that unigram penalties to random tokens (Algorithm~\\ref{alg:aug}) was easy to implement and produced sufficiently diverse responses.",
|
| 351 |
+
" ",
|
| 352 |
+
"\\section {Discussion and Future Work}",
|
| 353 |
+
" ",
|
| 354 |
+
"\\paragraph{What makes NMT-Fake* reviews difficult to detect?} First, NMT models allow the encoding of a relevant context for each review, which narrows down the possible choices of words that the model has to choose from. Our NMT model had a perplexity of approximately $25$, while the model of \\cite{yao2017automated} had a perplexity of approximately $90$ \\footnote{Personal communication with the authors}. Second, the beam search in NMT models narrows down choices to natural-looking sentences. Third, we observed that the NMT model produced \\emph{better structure} in the generated sentences (i.e. a more coherent story).",
|
| 355 |
+
" ",
|
| 356 |
+
"\\paragraph{Cost of generating reviews} With our setup, generating one review took less than one second. The cost of generation stems mainly from the overnight training. Assuming an electricity cost of 16 cents / kWh (California) and 8 hours of training, training the NMT model requires approximately 1.30 USD. This is a 90\\% reduction in time compared to the state-of-the-art \\cite{yao2017automated}. Furthermore, it is possible to generate both positive and negative reviews with the same model.",
|
| 357 |
+
" ",
|
| 358 |
+
"\\paragraph{Ease of customization} We experimented with inserting specific words into the text by increasing their log likelihoods in the beam search. We noticed that the success depended on the prevalence of the word in the training set. For example, adding a +5 to \\emph{Mike} in the log-likelihood resulted in approximately 10\\% prevalence of this word in the reviews. An attacker can therefore easily insert specific keywords to reviews, which can increase evasion probability.",
|
| 359 |
+
" ",
|
| 360 |
+
"\\paragraph{Ease of testing} Our diversification scheme is applicable during \\emph{generation phase}, and does not affect the training setup of the network in any way. Once the NMT model is obtained, it is easy to obtain several different variants of NMT-Fake reviews by varying parameters $b$ and $\\lambda$.",
|
| 361 |
+
" ",
|
| 362 |
+
" ",
|
| 363 |
+
" ",
|
| 364 |
+
"\\paragraph{Languages} The generation methodology is not per-se language-dependent. The requirement for successful generation is that sufficiently much data exists in the targeted language. However, our language model modifications require some knowledge of that target language's grammar to produce high-quality reviews.",
|
| 365 |
+
" ",
|
| 366 |
+
"\\paragraph{Generalizability of detection techniques} Currently, fake reviews are not universally detectable. Our results highlight that it is difficult to claim detection performance on unseen types of fake reviews (Section~\\ref{sec:automated}). We see this an open problem that deserves more attention in fake reviews research.",
|
| 367 |
+
" ",
|
| 368 |
+
"\\paragraph{Generalizability to other types of datasets} Our technique can be applied to any dataset, as long as there is sufficient training data for the NMT model. We used approximately 2.9 million reviews for this work.",
|
| 369 |
+
" ",
|
| 370 |
+
"\\section{Conclusion}",
|
| 371 |
+
" ",
|
| 372 |
+
"In this paper, we showed that neural machine translation models can be used to generate fake reviews that are very effective in deceiving even experienced, tech-savvy users.",
|
| 373 |
+
"This supports anecdotal evidence \\cite{national2017commission}.",
|
| 374 |
+
"Our technique is more effective than state-of-the-art \\cite{yao2017automated}.",
|
| 375 |
+
"We conclude that machine-aided fake review detection is necessary since human users are ineffective in identifying fake reviews.",
|
| 376 |
+
"We also showed that detectors trained using one type of fake reviews are not effective in identifying other types of fake reviews.",
|
| 377 |
+
"Robust detection of fake reviews is thus still an open problem.",
|
| 378 |
+
" ",
|
| 379 |
+
" ",
|
| 380 |
+
"\\section*{Acknowledgments}",
|
| 381 |
+
"We thank Tommi Gr\\\"{o}ndahl for assistance in planning user studies and the",
|
| 382 |
+
"participants of the user study for their time and feedback. We also thank",
|
| 383 |
+
"Luiza Sayfullina for comments that improved the manuscript.",
|
| 384 |
+
"We thank the authors of \\cite{yao2017automated} for answering questions about",
|
| 385 |
+
"their work.",
|
| 386 |
+
" ",
|
| 387 |
+
" ",
|
| 388 |
+
"\\bibliographystyle{splncs}",
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+
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| 537 |
+
" ",
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| 538 |
+
" ",
|
| 539 |
+
" ",
|
| 540 |
+
"\\section*{Appendix}",
|
| 541 |
+
" ",
|
| 542 |
+
"We present basic demographics of our MTurk study and the comparative study with experienced users in Table~\\ref{table:amt_pop}.",
|
| 543 |
+
" ",
|
| 544 |
+
"\\begin{table}",
|
| 545 |
+
"\\caption{User study statistics.}",
|
| 546 |
+
"\\begin{center}",
|
| 547 |
+
" \\begin{tabular}{ | l | c | c | }",
|
| 548 |
+
" \\hline",
|
| 549 |
+
" Quality & Mechanical Turk users & Experienced users\\\\",
|
| 550 |
+
" \\hline",
|
| 551 |
+
" Native English Speaker & Yes (20) & Yes (1) No (19) \\\\",
|
| 552 |
+
" Fluent in English & Yes (20) & Yes (20) \\\\",
|
| 553 |
+
" Age & 21-40 (17) 41-60 (3) & 21-25 (8) 26-30 (7) 31-35 (4) 41-45 (1)\\\\",
|
| 554 |
+
" Gender & Male (14) Female (6) & Male (17) Female (3)\\\\",
|
| 555 |
+
" Highest Education & High School (10) Bachelor (10) & Bachelor (9) Master (6) Ph.D. (5) \\\\",
|
| 556 |
+
" \\hline",
|
| 557 |
+
" \\end{tabular}",
|
| 558 |
+
" \\label{table:amt_pop}",
|
| 559 |
+
"\\end{center}",
|
| 560 |
+
"\\end{table}",
|
| 561 |
+
" ",
|
| 562 |
+
" ",
|
| 563 |
+
"Table~\\ref{table:openNMT-py_commands} shows a listing of the openNMT-py commands we used to create our NMT model and to generate fake reviews.",
|
| 564 |
+
" ",
|
| 565 |
+
"\\begin{table}[t]",
|
| 566 |
+
"\\caption{Listing of used openNMT-py commands.}",
|
| 567 |
+
"\\begin{center}",
|
| 568 |
+
" \\begin{tabular}{ | l | l | }",
|
| 569 |
+
" \\hline",
|
| 570 |
+
" Phase & Bash command \\\\",
|
| 571 |
+
" \\hline",
|
| 572 |
+
" Preprocessing & \\begin{lstlisting}[language=bash]",
|
| 573 |
+
"python preprocess.py -train_src context-train.txt",
|
| 574 |
+
"-train_tgt reviews-train.txt -valid_src context-val.txt",
|
| 575 |
+
"-valid_tgt reviews-val.txt -save_data model",
|
| 576 |
+
"-lower -tgt_words_min_frequency 10",
|
| 577 |
+
"\\end{lstlisting}",
|
| 578 |
+
" \\\\ & \\\\",
|
| 579 |
+
" Training & \\begin{lstlisting}[language=bash]",
|
| 580 |
+
"python train.py -data model -save_model model -epochs 8",
|
| 581 |
+
"-gpuid 0 -learning_rate_decay 0.5 -optim adam",
|
| 582 |
+
"-learning_rate 0.001 -start_decay_at 3\\end{lstlisting}",
|
| 583 |
+
" \\\\ & \\\\",
|
| 584 |
+
" Generation & \\begin{lstlisting}[language=bash]",
|
| 585 |
+
"python translate.py -model model_acc_35.54_ppl_25.68_e8.pt",
|
| 586 |
+
"-src context-tst.txt -output pred-e8.txt -replace_unk",
|
| 587 |
+
"-verbose -max_length 50 -gpu 0",
|
| 588 |
+
" \\end{lstlisting} \\\\",
|
| 589 |
+
" \\hline",
|
| 590 |
+
" \\end{tabular}",
|
| 591 |
+
" \\label{table:openNMT-py_commands}",
|
| 592 |
+
"\\end{center}",
|
| 593 |
+
"\\end{table}",
|
| 594 |
+
" ",
|
| 595 |
+
" ",
|
| 596 |
+
"Table~\\ref{table:MTurk_sub} shows the classification performance of Amazon Mechanical Turkers, separated across different categories of NMT-Fake reviews. The category with best performance ($b=0.3, \\lambda=-5$) is denoted as NMT-Fake*.",
|
| 597 |
+
" ",
|
| 598 |
+
"\\begin{table}[b]",
|
| 599 |
+
"\\caption{MTurk study subclass classification reports. Classes are imbalanced in ratio 1:6. Random predictions are $p_\\mathrm{human} = 86\\%$ and $p_\\mathrm{machine} = 14\\%$, with $r_\\mathrm{human} = r_\\mathrm{machine} = 50\\%$. Class-averaged F-scores for random predictions are $42\\%$.}",
|
| 600 |
+
"\\begin{center}",
|
| 601 |
+
" \\begin{tabular}{ | c || c |c |c | c | }",
|
| 602 |
+
" \\hline",
|
| 603 |
+
" $(b=0.3, \\lambda = -3)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 604 |
+
" Human & 89\\% & 63\\% & 73\\% & 994\\\\",
|
| 605 |
+
" NMT-Fake & 15\\% & 45\\% & 22\\% & 146 \\\\",
|
| 606 |
+
" \\hline",
|
| 607 |
+
" \\hline",
|
| 608 |
+
" $(b=0.3, \\lambda = -5)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 609 |
+
" Human & 86\\% & 63\\% & 73\\% & 994\\\\",
|
| 610 |
+
" NMT-Fake* & 16\\% & 40\\% & 23\\% & 171 \\\\",
|
| 611 |
+
" \\hline",
|
| 612 |
+
" \\hline",
|
| 613 |
+
" $(b=0.5, \\lambda = -4)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 614 |
+
" Human & 88\\% & 63\\% & 73\\% & 994\\\\",
|
| 615 |
+
" NMT-Fake & 21\\% & 55\\% & 30\\% & 181 \\\\",
|
| 616 |
+
" \\hline",
|
| 617 |
+
" \\hline",
|
| 618 |
+
" $(b=0.7, \\lambda = -3)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 619 |
+
" Human & 88\\% & 63\\% & 73\\% & 994\\\\",
|
| 620 |
+
" NMT-Fake & 19\\% & 50\\% & 27\\% & 170 \\\\",
|
| 621 |
+
" \\hline",
|
| 622 |
+
" \\hline",
|
| 623 |
+
" $(b=0.7, \\lambda = -5)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 624 |
+
" Human & 89\\% & 63\\% & 74\\% & 994\\\\",
|
| 625 |
+
" NMT-Fake & 21\\% & 57\\% & 31\\% & 174 \\\\",
|
| 626 |
+
" \\hline",
|
| 627 |
+
" \\hline",
|
| 628 |
+
" $(b=0.9, \\lambda = -4)$ & Precision & Recall & F-score & Support \\\\ \\hline",
|
| 629 |
+
" Human & 88\\% & 63\\% & 73\\% & 994\\\\",
|
| 630 |
+
" NMT-Fake & 18\\% & 50\\% & 27\\% & 164 \\\\",
|
| 631 |
+
" \\hline",
|
| 632 |
+
" \\end{tabular}",
|
| 633 |
+
" \\label{table:MTurk_sub}",
|
| 634 |
+
"\\end{center}",
|
| 635 |
+
"\\end{table}",
|
| 636 |
+
" ",
|
| 637 |
+
"Figure~\\ref{fig:screenshot} shows screenshots of the first two pages of our user study with experienced participants.",
|
| 638 |
+
" ",
|
| 639 |
+
"\\begin{figure}[ht]",
|
| 640 |
+
"\\centering",
|
| 641 |
+
"\\includegraphics[width=1.\\columnwidth]{figures/screenshot_7-3.png}",
|
| 642 |
+
"\\caption{",
|
| 643 |
+
"Screenshots of the first two pages in the user study. Example 1 is a NMT-Fake* review, the rest are human-written.",
|
| 644 |
+
"}",
|
| 645 |
+
"\\label{fig:screenshot}",
|
| 646 |
+
"\\end{figure}",
|
| 647 |
+
" ",
|
| 648 |
+
"Table~\\ref{table:features_adaboost} shows the features used to detect NMT-Fake reviews using the AdaBoost classifier.",
|
| 649 |
+
" ",
|
| 650 |
+
"\\begin{table}",
|
| 651 |
+
"\\caption{Features used in NMT-Fake review detector.}",
|
| 652 |
+
"\\begin{center}",
|
| 653 |
+
" \\begin{tabular}{ | l | c | }",
|
| 654 |
+
" \\hline",
|
| 655 |
+
" Feature type & Number of features \\\\ \\hline",
|
| 656 |
+
" \\hline",
|
| 657 |
+
" Readability features & 13 \\\\ \\hline",
|
| 658 |
+
" Unique POS tags & $~20$ \\\\ \\hline",
|
| 659 |
+
" Word unigrams & 22,831 \\\\ \\hline",
|
| 660 |
+
" 1/2/3/4-grams of simple part-of-speech tags & 54,240 \\\\ \\hline",
|
| 661 |
+
" 1/2/3-grams of detailed part-of-speech tags & 112,944 \\\\ \\hline",
|
| 662 |
+
" 1/2/3-grams of syntactic dependency tags & 93,195 \\\\ \\hline",
|
| 663 |
+
" \\end{tabular}",
|
| 664 |
+
" \\label{table:features_adaboost}",
|
| 665 |
+
"\\end{center}",
|
| 666 |
+
"\\end{table}",
|
| 667 |
+
" ",
|
| 668 |
+
"\\end{document}",
|
| 669 |
+
""
|
| 670 |
+
]
|
| 671 |
+
]
|
| 672 |
+
}
|
| 673 |
+
```
|
qasper-0050/instruction.md
ADDED
|
@@ -0,0 +1,56 @@
|
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|
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|
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|
|
|
| 1 |
+
Name of Paper: Is there Gender bias and stereotype in Portuguese Word Embeddings?
|
| 2 |
+
|
| 3 |
+
Question: Which word embeddings are analysed?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Related Work",
|
| 12 |
+
"Portuguese Embedding",
|
| 13 |
+
"Proposed Approach",
|
| 14 |
+
"Experiments",
|
| 15 |
+
"Final Remarks"
|
| 16 |
+
],
|
| 17 |
+
"paragraphs": [
|
| 18 |
+
[
|
| 19 |
+
"Recently, the transformative potential of machine learning (ML) has propelled ML into the forefront of mainstream media. In Brazil, the use of such technique has been widely diffused gaining more space. Thus, it is used to search for patterns, regularities or even concepts expressed in data sets BIBREF0 , and can be applied as a form of aid in several areas of everyday life.",
|
| 20 |
+
"Among the different definitions, ML can be seen as the ability to improve performance in accomplishing a task through the experience BIBREF1 . Thus, BIBREF2 presents this as a method of inferences of functions or hypotheses capable of solving a problem algorithmically from data representing instances of the problem. This is an important way to solve different types of problems that permeate computer science and other areas.",
|
| 21 |
+
"One of the main uses of ML is in text processing, where the analysis of the content the entry point for various learning algorithms. However, the use of this content can represent the insertion of different types of bias in training and may vary with the context worked. This work aims to analyze and remove gender stereotypes from word embedding in Portuguese, analogous to what was done in BIBREF3 for the English language. Hence, we propose to employ a public word2vec model pre-trained to analyze gender bias in the Portuguese language, quantifying biases present in the model so that it is possible to reduce the spreading of sexism of such models. There is also a stage of bias reducing over the results obtained in the model, where it is sought to analyze the effects of the application of gender distinction reduction techniques.",
|
| 22 |
+
"This paper is organized as follows: Section SECREF2 discusses related works. Section SECREF3 presents the Portuguese word2vec embeddings model used in this paper and Section SECREF4 proposes our method. Section SECREF5 presents experimental results, whose purpose is to verify results of a de-bias algorithm application in Portuguese embeddings word2vec model and a short discussion about it. Section SECREF6 brings our concluding remarks."
|
| 23 |
+
],
|
| 24 |
+
[
|
| 25 |
+
"There is a wide range of techniques that provide interesting results in the context of ML algorithms geared to the classification of data without discrimination; these techniques range from the pre-processing of data BIBREF4 to the use of bias removal techniques BIBREF5 in fact. Approaches linked to the data pre-processing step usually consist of methods based on improving the quality of the dataset after which the usual classification tools can be used to train a classifier. So, it starts from a baseline already stipulated by the execution of itself. On the other side of the spectrum, there are Unsupervised and semi-supervised learning techniques, that are attractive because they do not imply the cost of corpus annotation BIBREF6 , BIBREF7 , BIBREF8 , BIBREF9 .",
|
| 26 |
+
"The bias reduction is studied as a way to reduce discrimination through classification through different approaches BIBREF10 BIBREF11 . In BIBREF12 the authors propose to specify, implement, and evaluate the \u201cfairness-aware\" ML interface called themis-ml. In this interface, the main idea is to pick up a data set from a modified dataset. Themis-ml implements two methods for training fairness-aware models. The tool relies on two methods to make agnostic model type predictions: Reject Option Classification and Discrimination-Aware Ensemble Classification, these procedures being used to post-process predictions in a way that reduces potentially discriminatory predictions. According to the authors, it is possible to perceive the potential use of the method as a means of reducing bias in the use of ML algorithms.",
|
| 27 |
+
"In BIBREF3 , the authors propose a method to hardly reduce bias in English word embeddings collected from Google News. Using word2vec, they performed a geometric analysis of gender direction of the bias contained in the data. Using this property with the generation of gender-neutral analogies, a methodology was provided for modifying an embedding to remove gender stereotypes. Some metrics were defined to quantify both direct and indirect gender biases in embeddings and to develop algorithms to reduce bias in some embedding. Hence, the authors show that embeddings can be used in applications without amplifying gender bias."
|
| 28 |
+
],
|
| 29 |
+
[
|
| 30 |
+
"In BIBREF13 , the quality of the representation of words through vectors in several models is discussed. According to the authors, the ability to train high-quality models using simplified architectures is useful in models composed of predictive methods that try to predict neighboring words with one or more context words, such as Word2Vec. Word embeddings have been used to provide meaningful representations for words in an efficient way.",
|
| 31 |
+
"In BIBREF14 , several word embedding models trained in a large Portuguese corpus are evaluated. Within the Word2Vec model, two training strategies were used. In the first, namely Skip-Gram, the model is given the word and attempts to predict its neighboring words. The second, Continuous Bag-of-Words (CBOW), the model is given the sequence of words without the middle one and attempts to predict this omitted word. The latter was chosen for application in the present proposal.",
|
| 32 |
+
"The authors of BIBREF14 claim to have collected a large corpus from several sources to obtain a multi-genre corpus representative of the Portuguese language. Hence, it comprehensively covers different expressions of the language, making it possible to analyze gender bias and stereotype in Portuguese word embeddings. The dataset used was tokenized and normalized by the authors to reduce the corpus vocabulary size, under the premise that vocabulary reduction provides more representative vectors."
|
| 33 |
+
],
|
| 34 |
+
[
|
| 35 |
+
"Some linguists point out that the female gender is, in Portuguese, a particularization of the masculine. In this way the only gender mark is the feminine, the others being considered without gender (including names considered masculine). In BIBREF15 the gender representation in Portuguese is associated with a set of phenomena, not only from a linguistic perspective but also from a socio-cultural perspective. Since most of the termination of words (e.g., advogada and advogado) are used to indicate to whom the expression refers, stereotypes can be explained through communication. This implies the presence of biases when dealing with terms such as those referring to professions.",
|
| 36 |
+
"Figure FIGREF1 illustrates the approach proposed in this work. First, using a list of professions relating the identification of female and male who perform it as a parameter, we evaluate the accuracy of similarity generated by the embeddings. Then, getting the biased results, we apply the De-bias algorithm BIBREF3 aiming to reduce sexist analogies previous generated. Thus, all the results are analyzed by comparing the accuracies.",
|
| 37 |
+
"Using the word2vec model available in a public repository BIBREF14 , the proposal involves the analysis of the most similar analogies generated before and after the application of the BIBREF3 . The work is focused on the analysis of gender bias associated with professions in word embeddings. So therefore into the evaluation of the accuracy of the associations generated, aiming at achieving results as good as possible without prejudicing the evaluation metrics.",
|
| 38 |
+
"Algorithm SECREF4 describes the method performed during the evaluation of the gender bias presence. In this method we try to evaluate the accuracy of the analogies generated through the model, that is, to verify the cases of association matching generated between the words.",
|
| 39 |
+
"[!htb] Model Evaluation [1]",
|
| 40 |
+
"w2v_evaluate INLINEFORM0 open_model( INLINEFORM1 ) count = 0 INLINEFORM2 in INLINEFORM3 read list of tuples x = model.most_similar(positive=[`ela', male], negative=[`ele'])",
|
| 41 |
+
"x = female count += 1 accuracy = count/size(profession_pairs) return accuracy"
|
| 42 |
+
],
|
| 43 |
+
[
|
| 44 |
+
"The purpose of this section is to perform different analysis concerning bias in word2vec models with Portuguese embeddings. The Continuous Bag-of-Words model used was provided by BIBREF14 (described in Section SECREF3 ). For these experiments, we use a model containing 934966 words of dimension 300 per vector representation. To realize the experiments, a list containing fifty professions labels for female and male was used as the parameter of similarity comparison.",
|
| 45 |
+
"Using the python library gensim, we evaluate the extreme analogies generated when comparing vectors like: INLINEFORM0 , where INLINEFORM1 represents the item from professions list and INLINEFORM2 the expected association. The most similarity function finds the top-N most similar entities, computing cosine similarity between a simple mean of the projection weight vectors of the given docs. Figure FIGREF4 presents the most extreme analogies results obtained from the model using these comparisons.",
|
| 46 |
+
"Applying the Algorithm SECREF4 , we check the accuracy obtained with the similarity function before and after the application of the de-bias method. Table TABREF3 presents the corresponding results. In cases like the analogy of `gar\u00e7onete' to `stripper' (Figure FIGREF4 , line 8), it is possible to observe that the relationship stipulated between terms with sexual connotation and females is closer than between females and professions. While in the male model, even in cases of non-compliance, the closest analogy remains in the professional environment.",
|
| 47 |
+
"Using a confidence factor of 99%, when comparing the correctness levels of the model with and without the reduction of bias, the prediction of the model with bias is significantly better. Different authors BIBREF16 BIBREF17 show that the removal of bias in models produces a negative impact on the quality of the model. On the other hand, it is observed that even with a better hit rate the correctness rate in the prediction of related terms is still low."
|
| 48 |
+
],
|
| 49 |
+
[
|
| 50 |
+
"This paper presents an analysis of the presence of gender bias in Portuguese word embeddings. Even though it is a work in progress, the proposal showed promising results in analyzing predicting models.",
|
| 51 |
+
"A possible extension of the work involves deepening the analysis of the results obtained, seeking to achieve higher accuracy rates and fairer models to be used in machine learning techniques. Thus, these studies can involve tests with different methods of pre-processing the data to the use of different models, as well as other factors that may influence the results generated. This deepening is necessary since the model's accuracy is not high.",
|
| 52 |
+
"To conclude, we believe that the presence of gender bias and stereotypes in the Portuguese language is found in different spheres of language, and it is important to study ways of mitigating different types of discrimination. As such, it can be easily applied to analyze racists bias into the language, such as different types of preconceptions."
|
| 53 |
+
]
|
| 54 |
+
]
|
| 55 |
+
}
|
| 56 |
+
```
|
qasper-0056/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: LAXARY: A Trustworthy Explainable Twitter Analysis Model for Post-Traumatic Stress Disorder Assessment
|
| 2 |
+
|
| 3 |
+
Question: How is the intensity of the PTSD established?
|
qasper-0057/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: LAXARY: A Trustworthy Explainable Twitter Analysis Model for Post-Traumatic Stress Disorder Assessment
|
| 2 |
+
|
| 3 |
+
Question: How is LIWC incorporated into this system?
|
qasper-0058/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: LAXARY: A Trustworthy Explainable Twitter Analysis Model for Post-Traumatic Stress Disorder Assessment
|
| 2 |
+
|
| 3 |
+
Question: How many twitter users are surveyed using the clinically validated survey?
|
qasper-0059/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: LAXARY: A Trustworthy Explainable Twitter Analysis Model for Post-Traumatic Stress Disorder Assessment
|
| 2 |
+
|
| 3 |
+
Question: Which clinically validated survey tools are used?
|
qasper-0060/instruction.md
ADDED
|
@@ -0,0 +1,70 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: Comprehensive Named Entity Recognition on CORD-19 with Distant or Weak Supervision
|
| 2 |
+
|
| 3 |
+
Question: Did they experiment with the dataset?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"CORD-19-NER Dataset ::: Corpus",
|
| 12 |
+
"CORD-19-NER Dataset ::: NER Methods",
|
| 13 |
+
"Results ::: NER Annotation Results",
|
| 14 |
+
"Results ::: Top-Frequent Entity Summarization",
|
| 15 |
+
"Conclusion",
|
| 16 |
+
"Acknowledgment"
|
| 17 |
+
],
|
| 18 |
+
"paragraphs": [
|
| 19 |
+
[
|
| 20 |
+
"Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease was first identified in 2019 in Wuhan, Central China, and has since spread globally, resulting in the 2019\u20132020 coronavirus pandemic. On March 16th, 2020, researchers and leaders from the Allen Institute for AI, Chan Zuckerberg Initiative (CZI), Georgetown University\u2019s Center for Security and Emerging Technology (CSET), Microsoft, and the National Library of Medicine (NLM) at the National Institutes of Health released the COVID-19 Open Research Dataset (CORD-19) of scholarly literature about COVID-19, SARS-CoV-2, and the coronavirus group.",
|
| 21 |
+
"Named entity recognition (NER) is a fundamental step in text mining system development to facilitate the COVID-19 studies. There is critical need for NER methods that can quickly adapt to all the COVID-19 related new types without much human effort for training data annotation. We created this CORD-19-NER dataset with comprehensive named entity annotation on the CORD-19 corpus (2020-03-13). This dataset covers 75 fine-grained named entity types. CORD-19-NER is automatically generated by combining the annotation results from four sources. In the following sections, we introduce the details of CORD-19-NER dataset construction. We also show some NER annotation results in this dataset."
|
| 22 |
+
],
|
| 23 |
+
[
|
| 24 |
+
"The corpus is generated from the 29,500 documents in the CORD-19 corpus (2020-03-13). We first merge all the meta-data (all_sources_metadata_2020-03-13.csv) with their corresponding full-text papers. Then we create a tokenized corpus (CORD-19-corpus.json) for further NER annotations.",
|
| 25 |
+
"Corpus Tokenization. The raw corpus is a combination of the \u201ctitle\", \u201cabstract\" and \u201cfull-text\" from the CORD-19 corpus. We first conduct automatic phrase mining on the raw corpus using AutoPhrase BIBREF0. Then we do the second round of tokenization with Spacy on the phrase-replaced corpus. We have observed that keeping the AutoPhrase results will significantly improve the distantly- and weakly-supervised NER performance.",
|
| 26 |
+
"Key Items. The tokenized corpus includes the following items:",
|
| 27 |
+
"doc_id: the line number (0-29499) in \u201call_sources_metadata_2020-03-13.csv\" in the CORD-19 corpus (2020-03-13).",
|
| 28 |
+
"sents: [sent_id, sent_tokens], tokenized sentences and words as described above.",
|
| 29 |
+
"source: CZI (1236 records), PMC (27337), bioRxiv (566) and medRxiv (361).",
|
| 30 |
+
"doi: populated for all BioRxiv/MedRxiv paper records and most of the other records (26357 non null).",
|
| 31 |
+
"pmcid: populated for all PMC paper records (27337 non null).",
|
| 32 |
+
"pubmed_id: populated for some of the records.",
|
| 33 |
+
"Other keys: publish_time, authors and journal.",
|
| 34 |
+
"The tokenized corpus (CORD-19-corpus.json) with the file schema and detailed descriptions can be found in our CORD-19-NER dataset."
|
| 35 |
+
],
|
| 36 |
+
[
|
| 37 |
+
"CORD-19-NER annotation is a combination from four sources with different NER methods:",
|
| 38 |
+
"Pre-trained NER on 18 general entity types from Spacy using the model \u201cen_core_web_sm\".",
|
| 39 |
+
"Pre-trained NER on 18 biomedical entity types from SciSpacy using the model \u201cen_ner_bionlp13cg_md\".",
|
| 40 |
+
"Knowledge base (KB)-guided NER on 127 biomedical entity types with our distantly-supervised NER methods BIBREF1, BIBREF2. We do not require any human annotated training data for the NER model training. Instead, We rely on UMLS as the input KB for distant supervision.",
|
| 41 |
+
"Seed-guided NER on 9 new entity types (specifically related to the COVID-19 studies) with our weakly-supervised NER method. We only require several (10-20) human-input seed entities for each new type. Then we expand the seed entity sets with CatE BIBREF3 and apply our distant NER method for the new entity type recognition.",
|
| 42 |
+
"The 9 new entity types with examples of their input seed are as follows:",
|
| 43 |
+
"Coronavirus: COVID-19, SARS, MERS, etc.",
|
| 44 |
+
"Viral Protein: Hemagglutinin, GP120, etc.",
|
| 45 |
+
"Livestock: cattle, sheep, pig, etc.",
|
| 46 |
+
"Wildlife: bats, wild animals, wild birds, etc",
|
| 47 |
+
"Evolution: genetic drift, natural selection, mutation rate, etc",
|
| 48 |
+
"Physical Science: atomic charge, Amber force fields, Van der Waals interactions, etc.",
|
| 49 |
+
"Substrate: blood, sputum, urine, etc.",
|
| 50 |
+
"Material: copper, stainless steel, plastic, etc.",
|
| 51 |
+
"Immune Response: adaptive immune response, cell mediated immunity, innate immunity, etc.",
|
| 52 |
+
"We merged all the entity types from the four sources and reorganized them into one entity type hierarchy. Specifically, we align all the types from SciSpacy to UMLS. We also merge some fine-grained UMLS entity types to their more coarse-grained types based on the corpus count. Then we get a final entity type hierarchy with 75 fine-grained entity types used in our annotations. The entity type hierarchy (CORD-19-types.xlsx) can be found in our CORD-19-NER dataset.",
|
| 53 |
+
"Then we conduct named entity annotation with the four NER methods on the 75 fine-grained entity types. After we get the NER annotation results with the four different methods, we merge the results into one file. The conflicts are resolved by giving priority to different entity types annotated by different methods according to their annotation quality. The final entity annotation results (CORD-19-ner.json) with the file schema and detailed descriptions can be found in our CORD-19-NER dataset."
|
| 54 |
+
],
|
| 55 |
+
[
|
| 56 |
+
"In Figure FIGREF28, we show some examples of the annotation results in CORD-19-NER. We can see that our distantly- or weakly supervised methods achieve high quality recognizing the new entity types, requiring only several seed examples as the input. For example, we recognized \u201cSARS-CoV-2\" as the \u201cCORONAVIRUS\" type, \u201cbat\" and \u201cpangolins\" as the \u201cWILDLIFE\" type and \u201cVan der Waals forces\" as the \u201cPHYSICAL_SCIENCE\" type. This NER annotation results help downstream text mining tasks in discovering the origin and the physical nature of the virus. Our NER methods are domain-independent that can be applied to corpus in different domains. In addition, we show another example of NER annotation on New York Times with our system in Figure FIGREF29.",
|
| 57 |
+
"In Figure FIGREF30, we show the comparison of our annotation results with existing NER/BioNER systems. In Figure FIGREF30, we can see that only our method can identify \u201cSARS-CoV-2\" as a coronavirus. In Figure FIGREF30, we can see that our method can identify many more entities such as \u201cpylogenetic\" as a evolution term and \u201cbat\" as a wildlife. In Figure FIGREF30, we can also see that our method can identify many more entities such as \u201cracism\" as a social behavior. In summary, our distantly- and weakly-supervised NER methods are reliable for high-quality entity recognition without requiring human effort for training data annotation."
|
| 58 |
+
],
|
| 59 |
+
[
|
| 60 |
+
"In Table TABREF34, we show some examples of the most frequent entities in the annotated corpus. Specifically, we show the entity types including both our new types and some UMLS types that have not been manually annotated before. We find our annotated entities very informative for the COVID-19 studies. For example, the most frequent entities for the type \u201cSIGN_OR_SYMPTOM behavior\" includes \u201ccough\" and \u201crespiratory symptoms\" that are the most common symptoms for COVID-19 . The most frequent entities for the type \u201cINDIVIDUAL_BEHAVIOR\" includes \u201chand hygiene\", \u201cdisclosures\" and \u201cabsenteeism\", which indicates that people focus more on hand cleaning for the COVID-19 issue. Also, the most frequent entities for the type \u201cMACHINE_ACTIVITY\" includes \u201cmachine learning\", \u201cdata processing\" and \u201cautomation\", which indicates that people focus more on the automated methods that can process massive data for the COVID-19 studies. This type also includes \u201ctelecommunication\" as the top results, which is quite reasonable under the current COVID-19 situation. More examples can be found in our dataset."
|
| 61 |
+
],
|
| 62 |
+
[
|
| 63 |
+
"In the future, we will further improve the CORD-19-NER dataset quality. We will also build text mining systems based on the CORD-19-NER dataset with richer functionalities. We hope this dataset can help the text mining community build downstream applications. We also hope this dataset can bring insights for the COVID-19 studies, both on the biomedical side and on the social side."
|
| 64 |
+
],
|
| 65 |
+
[
|
| 66 |
+
"Research was sponsored in part by US DARPA KAIROS Program No. FA8750-19-2-1004 and SocialSim Program No. W911NF-17-C-0099, National Science Foundation IIS 16-18481, IIS 17-04532, and IIS-17-41317, and DTRA HDTRA11810026. Any opinions, findings, and conclusions or recommendations expressed herein are those of the authors and should not be interpreted as necessarily representing the views, either expressed or implied, of DARPA or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for government purposes notwithstanding any copyright annotation hereon. The views and conclusions contained in this paper are those of the authors and should not be interpreted as representing any funding agencies."
|
| 67 |
+
]
|
| 68 |
+
]
|
| 69 |
+
}
|
| 70 |
+
```
|
qasper-0061/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
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|
|
|
| 1 |
+
Name of Paper: Comprehensive Named Entity Recognition on CORD-19 with Distant or Weak Supervision
|
| 2 |
+
|
| 3 |
+
Question: What is the size of this dataset?
|
qasper-0066/instruction.md
ADDED
|
@@ -0,0 +1,154 @@
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|
|
| 1 |
+
Name of Paper: Word Sense Disambiguation for 158 Languages using Word Embeddings Only
|
| 2 |
+
|
| 3 |
+
Question: Is the method described in this work a clustering-based method?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"",
|
| 11 |
+
" ::: ",
|
| 12 |
+
" ::: ::: ",
|
| 13 |
+
"Introduction",
|
| 14 |
+
"Related Work",
|
| 15 |
+
"Algorithm for Word Sense Induction",
|
| 16 |
+
"Algorithm for Word Sense Induction ::: SenseGram: A Baseline Graph-based Word Sense Induction Algorithm",
|
| 17 |
+
"Algorithm for Word Sense Induction ::: egvi (Ego-Graph Vector Induction): A Novel Word Sense Induction Algorithm ::: Induction of Sense Inventories",
|
| 18 |
+
"Algorithm for Word Sense Induction ::: egvi (Ego-Graph Vector Induction): A Novel Word Sense Induction Algorithm ::: Labelling of Induced Senses",
|
| 19 |
+
"Algorithm for Word Sense Induction ::: egvi (Ego-Graph Vector Induction): A Novel Word Sense Induction Algorithm ::: Word Sense Disambiguation",
|
| 20 |
+
"System Design",
|
| 21 |
+
"System Design ::: Construction of Sense Inventories",
|
| 22 |
+
"System Design ::: Word Sense Disambiguation System",
|
| 23 |
+
"Evaluation",
|
| 24 |
+
"Evaluation ::: Lexical Similarity and Relatedness ::: Experimental Setup",
|
| 25 |
+
"Evaluation ::: Lexical Similarity and Relatedness ::: Discussion of Results",
|
| 26 |
+
"Evaluation ::: Word Sense Disambiguation",
|
| 27 |
+
"Evaluation ::: Word Sense Disambiguation ::: Experimental Setup",
|
| 28 |
+
"Evaluation ::: Word Sense Disambiguation ::: Discussion of Results",
|
| 29 |
+
"Evaluation ::: Analysis",
|
| 30 |
+
"Conclusions and Future Work",
|
| 31 |
+
"Acknowledgements"
|
| 32 |
+
],
|
| 33 |
+
"paragraphs": [
|
| 34 |
+
[
|
| 35 |
+
"1.1em"
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"1.1.1em"
|
| 39 |
+
],
|
| 40 |
+
[
|
| 41 |
+
"1.1.1.1em",
|
| 42 |
+
"ru=russian",
|
| 43 |
+
"",
|
| 44 |
+
"$^1$Skolkovo Institute of Science and Technology, Moscow, Russia",
|
| 45 |
+
"v.logacheva@skoltech.ru",
|
| 46 |
+
"$^2$Ural Federal University, Yekaterinburg, Russia",
|
| 47 |
+
"$^3$Universit\u00e4t Hamburg, Hamburg, Germany",
|
| 48 |
+
"$^4$Universit\u00e4t Mannheim, Mannheim, Germany",
|
| 49 |
+
"$^5$University of Oslo, Oslo, Norway",
|
| 50 |
+
"$^6$Higher School of Economics, Moscow, Russia",
|
| 51 |
+
"Disambiguation of word senses in context is easy for humans, but is a major challenge for automatic approaches. Sophisticated supervised and knowledge-based models were developed to solve this task. However, (i) the inherent Zipfian distribution of supervised training instances for a given word and/or (ii) the quality of linguistic knowledge representations motivate the development of completely unsupervised and knowledge-free approaches to word sense disambiguation (WSD). They are particularly useful for under-resourced languages which do not have any resources for building either supervised and/or knowledge-based models. In this paper, we present a method that takes as input a standard pre-trained word embedding model and induces a fully-fledged word sense inventory, which can be used for disambiguation in context. We use this method to induce a collection of sense inventories for 158 languages on the basis of the original pre-trained fastText word embeddings by Grave:18, enabling WSD in these languages. Models and system are available online.",
|
| 52 |
+
"word sense induction, word sense disambiguation, word embeddings, sense embeddings, graph clustering"
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"There are many polysemous words in virtually any language. If not treated as such, they can hamper the performance of all semantic NLP tasks BIBREF0. Therefore, the task of resolving the polysemy and choosing the most appropriate meaning of a word in context has been an important NLP task for a long time. It is usually referred to as Word Sense Disambiguation (WSD) and aims at assigning meaning to a word in context.",
|
| 56 |
+
"The majority of approaches to WSD are based on the use of knowledge bases, taxonomies, and other external manually built resources BIBREF1, BIBREF2. However, different senses of a polysemous word occur in very diverse contexts and can potentially be discriminated with their help. The fact that semantically related words occur in similar contexts, and diverse words do not share common contexts, is known as distributional hypothesis and underlies the technique of constructing word embeddings from unlabelled texts. The same intuition can be used to discriminate between different senses of individual words. There exist methods of training word embeddings that can detect polysemous words and assign them different vectors depending on their contexts BIBREF3, BIBREF4. Unfortunately, many wide-spread word embedding models, such as GloVe BIBREF5, word2vec BIBREF6, fastText BIBREF7, do not handle polysemous words. Words in these models are represented with single vectors, which were constructed from diverse sets of contexts corresponding to different senses. In such cases, their disambiguation needs knowledge-rich approaches.",
|
| 57 |
+
"We tackle this problem by suggesting a method of post-hoc unsupervised WSD. It does not require any external knowledge and can separate different senses of a polysemous word using only the information encoded in pre-trained word embeddings. We construct a semantic similarity graph for words and partition it into densely connected subgraphs. This partition allows for separating different senses of polysemous words. Thus, the only language resource we need is a large unlabelled text corpus used to train embeddings. This makes our method applicable to under-resourced languages. Moreover, while other methods of unsupervised WSD need to train embeddings from scratch, we perform retrofitting of sense vectors based on existing word embeddings.",
|
| 58 |
+
"We create a massively multilingual application for on-the-fly word sense disambiguation. When receiving a text, the system identifies its language and performs disambiguation of all the polysemous words in it based on pre-extracted word sense inventories. The system works for 158 languages, for which pre-trained fastText embeddings available BIBREF8. The created inventories are based on these embeddings. To the best of our knowledge, our system is the only WSD system for the majority of the presented languages. Although it does not match the state of the art for resource-rich languages, it is fully unsupervised and can be used for virtually any language.",
|
| 59 |
+
"The contributions of our work are the following:",
|
| 60 |
+
"[noitemsep]",
|
| 61 |
+
"We release word sense inventories associated with fastText embeddings for 158 languages.",
|
| 62 |
+
"We release a system that allows on-the-fly word sense disambiguation for 158 languages.",
|
| 63 |
+
"We present egvi (Ego-Graph Vector Induction), a new algorithm of unsupervised word sense induction, which creates sense inventories based on pre-trained word vectors."
|
| 64 |
+
],
|
| 65 |
+
[
|
| 66 |
+
"There are two main scenarios for WSD: the supervised approach that leverages training corpora explicitly labelled for word sense, and the knowledge-based approach that derives sense representation from lexical resources, such as WordNet BIBREF9. In the supervised case WSD can be treated as a classification problem. Knowledge-based approaches construct sense embeddings, i.e. embeddings that separate various word senses.",
|
| 67 |
+
"SupWSD BIBREF10 is a state-of-the-art system for supervised WSD. It makes use of linear classifiers and a number of features such as POS tags, surrounding words, local collocations, word embeddings, and syntactic relations. GlossBERT model BIBREF11, which is another implementation of supervised WSD, achieves a significant improvement by leveraging gloss information. This model benefits from sentence-pair classification approach, introduced by Devlin:19 in their BERT contextualized embedding model. The input to the model consists of a context (a sentence which contains an ambiguous word) and a gloss (sense definition) from WordNet. The context-gloss pair is concatenated through a special token ([SEP]) and classified as positive or negative.",
|
| 68 |
+
"On the other hand, sense embeddings are an alternative to traditional word vector models such as word2vec, fastText or GloVe, which represent monosemous words well but fail for ambiguous words. Sense embeddings represent individual senses of polysemous words as separate vectors. They can be linked to an explicit inventory BIBREF12 or induce a sense inventory from unlabelled data BIBREF13. LSTMEmbed BIBREF13 aims at learning sense embeddings linked to BabelNet BIBREF14, at the same time handling word ordering, and using pre-trained embeddings as an objective. Although it was tested only on English, the approach can be easily adapted to other languages present in BabelNet. However, manually labelled datasets as well as knowledge bases exist only for a small number of well-resourced languages. Thus, to disambiguate polysemous words in other languages one has to resort to fully unsupervised techniques.",
|
| 69 |
+
"The task of Word Sense Induction (WSI) can be seen as an unsupervised version of WSD. WSI aims at clustering word senses and does not require to map each cluster to a predefined sense. Instead of that, word sense inventories are induced automatically from the clusters, treating each cluster as a single sense of a word. WSI approaches fall into three main groups: context clustering, word ego-network clustering and synonyms (or substitute) clustering.",
|
| 70 |
+
"Context clustering approaches consist in creating vectors which characterise words' contexts and clustering these vectors. Here, the definition of context may vary from window-based context to latent topic-alike context. Afterwards, the resulting clusters are either used as senses directly BIBREF15, or employed further to learn sense embeddings via Chinese Restaurant Process algorithm BIBREF16, AdaGram, a Bayesian extension of the Skip-Gram model BIBREF17, AutoSense, an extension of the LDA topic model BIBREF18, and other techniques.",
|
| 71 |
+
"Word ego-network clustering is applied to semantic graphs. The nodes of a semantic graph are words, and edges between them denote semantic relatedness which is usually evaluated with cosine similarity of the corresponding embeddings BIBREF19 or by PMI-like measures BIBREF20. Word senses are induced via graph clustering algorithms, such as Chinese Whispers BIBREF21 or MaxMax BIBREF22. The technique suggested in our work belongs to this class of methods and is an extension of the method presented by Pelevina:16.",
|
| 72 |
+
"Synonyms and substitute clustering approaches create vectors which represent synonyms or substitutes of polysemous words. Such vectors are created using synonymy dictionaries BIBREF23 or context-dependent substitutes obtained from a language model BIBREF24. Analogously to previously described techniques, word senses are induced by clustering these vectors."
|
| 73 |
+
],
|
| 74 |
+
[
|
| 75 |
+
"The majority of word vector models do not discriminate between multiple senses of individual words. However, a polysemous word can be identified via manual analysis of its nearest neighbours\u2014they reflect different senses of the word. Table TABREF7 shows manually sense-labelled most similar terms to the word Ruby according to the pre-trained fastText model BIBREF8. As it was suggested early by Widdows:02, the distributional properties of a word can be used to construct a graph of words that are semantically related to it, and if a word is polysemous, such graph can easily be partitioned into a number of densely connected subgraphs corresponding to different senses of this word. Our algorithm is based on the same principle."
|
| 76 |
+
],
|
| 77 |
+
[
|
| 78 |
+
"SenseGram is the method proposed by Pelevina:16 that separates nearest neighbours to induce word senses and constructs sense embeddings for each sense. It starts by constructing an ego-graph (semantic graph centred at a particular word) of the word and its nearest neighbours. The edges between the words denote their semantic relatedness, e.g. the two nodes are joined with an edge if cosine similarity of the corresponding embeddings is higher than a pre-defined threshold. The resulting graph can be clustered into subgraphs which correspond to senses of the word.",
|
| 79 |
+
"The sense vectors are then constructed by averaging embeddings of words in each resulting cluster. In order to use these sense vectors for word sense disambiguation in text, the authors compute the probabilities of sense vectors of a word given its context or the similarity of the sense vectors to the context."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"One of the downsides of the described above algorithm is noise in the generated graph, namely, unrelated words and wrong connections. They hamper the separation of the graph. Another weak point is the imbalance in the nearest neighbour list, when a large part of it is attributed to the most frequent sense, not sufficiently representing the other senses. This can lead to construction of incorrect sense vectors.",
|
| 83 |
+
"We suggest a more advanced procedure of graph construction that uses the interpretability of vector addition and subtraction operations in word embedding space BIBREF6 while the previous algorithm only relies on the list of nearest neighbours in word embedding space. The key innovation of our algorithm is the use of vector subtraction to find pairs of most dissimilar graph nodes and construct the graph only from the nodes included in such \u201canti-edges\u201d. Thus, our algorithm is based on graph-based word sense induction, but it also relies on vector-based operations between word embeddings to perform filtering of graph nodes. Analogously to the work of Pelevina:16, we construct a semantic relatedness graph from a list of nearest neighbours, but we filter this list using the following procedure:",
|
| 84 |
+
"Extract a list $\\mathcal {N}$ = {$w_{1}$, $w_{2}$, ..., $w_{N}$} of $N$ nearest neighbours for the target (ego) word vector $w$.",
|
| 85 |
+
"Compute a list $\\Delta $ = {$\\delta _{1}$, $\\delta _{2}$, ..., $\\delta _{N}$} for each $w_{i}$ in $\\mathcal {N}$, where $\\delta _{i}~=~w-w_{i}$. The vectors in $\\delta $ contain the components of sense of $w$ which are not related to the corresponding nearest neighbours from $\\mathcal {N}$.",
|
| 86 |
+
"Compute a list $\\overline{\\mathcal {N}}$ = {$\\overline{w_{1}}$, $\\overline{w_{2}}$, ..., $\\overline{w_{N}}$}, such that $\\overline{w_{i}}$ is in the top nearest neighbours of $\\delta _{i}$ in the embedding space. In other words, $\\overline{w_{i}}$ is a word which is the most similar to the target (ego) word $w$ and least similar to its neighbour $w_{i}$. We refer to $\\overline{w_{i}}$ as an anti-pair of $w_{i}$. The set of $N$ nearest neighbours and their anti-pairs form a set of anti-edges i.e. pairs of most dissimilar nodes \u2013 those which should not be connected: $\\overline{E} = \\lbrace (w_{1},\\overline{w_{1}}), (w_{2},\\overline{w_{2}}), ..., (w_{N},\\overline{w_{N}})\\rbrace $.",
|
| 87 |
+
"To clarify this, consider the target (ego) word $w = \\textit {python}$, its top similar term $w_1 = \\textit {Java}$ and the resulting anti-pair $\\overline{w_i} = \\textit {snake}$ which is the top related term of $\\delta _1 = w - w_1$. Together they form an anti-edge $(w_i,\\overline{w_i})=(\\textit {Java}, \\textit {snake})$ composed of a pair of semantically dissimilar terms.",
|
| 88 |
+
"Construct $V$, the set of vertices of our semantic graph $G=(V,E)$ from the list of anti-edges $\\overline{E}$, with the following recurrent procedure: $V = V \\cup \\lbrace w_{i}, \\overline{w_{i}}: w_{i} \\in \\mathcal {N}, \\overline{w_{i}} \\in \\mathcal {N}\\rbrace $, i.e. we add a word from the list of nearest neighbours and its anti-pair only if both of them are nearest neighbours of the original word $w$. We do not add $w$'s nearest neighbours if their anti-pairs do not belong to $\\mathcal {N}$. Thus, we add only words which can help discriminating between different senses of $w$.",
|
| 89 |
+
"Construct the set of edges $E$ as follows. For each $w_{i}~\\in ~\\mathcal {N}$ we extract a set of its $K$ nearest neighbours $\\mathcal {N}^{\\prime }_{i} = \\lbrace u_{1}, u_{2}, ..., u_{K}\\rbrace $ and define $E = \\lbrace (w_{i}, u_{j}): w_{i}~\\in ~V, u_j~\\in ~V, u_{j}~\\in ~\\mathcal {N}^{\\prime }_{i}, u_{j}~\\ne ~\\overline{w_{i}}\\rbrace $. In other words, we remove edges between a word $w_{i}$ and its nearest neighbour $u_j$ if $u_j$ is also its anti-pair. According to our hypothesis, $w_{i}$ and $\\overline{w_{i}}$ belong to different senses of $w$, so they should not be connected (i.e. we never add anti-edges into $E$). Therefore, we consider any connection between them as noise and remove it.",
|
| 90 |
+
"Note that $N$ (the number of nearest neighbours for the target word $w$) and $K$ (the number of nearest neighbours of $w_{ci}$) do not have to match. The difference between these parameters is the following. $N$ defines how many words will be considered for the construction of ego-graph. On the other hand, $K$ defines the degree of relatedness between words in the ego-graph \u2014 if $K = 50$, then we will connect vertices $w$ and $u$ with an edge only if $u$ is in the list of 50 nearest neighbours of $w$. Increasing $K$ increases the graph connectivity and leads to lower granularity of senses.",
|
| 91 |
+
"According to our hypothesis, nearest neighbours of $w$ are grouped into clusters in the vector space, and each of the clusters corresponds to a sense of $w$. The described vertices selection procedure allows picking the most representative members of these clusters which are better at discriminating between the clusters. In addition to that, it helps dealing with the cases when one of the clusters is over-represented in the nearest neighbour list. In this case, many elements of such a cluster are not added to $V$ because their anti-pairs fall outside the nearest neighbour list. This also improves the quality of clustering.",
|
| 92 |
+
"After the graph construction, the clustering is performed using the Chinese Whispers algorithm BIBREF21. This is a bottom-up clustering procedure that does not require to pre-define the number of clusters, so it can correctly process polysemous words with varying numbers of senses as well as unambiguous words.",
|
| 93 |
+
"Figure FIGREF17 shows an example of the resulting pruned graph of for the word Ruby for $N = 50$ nearest neighbours in terms of the fastText cosine similarity. In contrast to the baseline method by BIBREF19 where all 50 terms are clustered, in the method presented in this section we sparsify the graph by removing 13 nodes which were not in the set of the \u201canti-edges\u201d i.e. pairs of most dissimilar terms out of these 50 neighbours. Examples of anti-edges i.e. pairs of most dissimilar terms for this graph include: (Haskell, Sapphire), (Garnet, Rails), (Opal, Rubyist), (Hazel, RubyOnRails), and (Coffeescript, Opal)."
|
| 94 |
+
],
|
| 95 |
+
[
|
| 96 |
+
"We label each word cluster representing a sense to make them and the WSD results interpretable by humans. Prior systems used hypernyms to label the clusters BIBREF25, BIBREF26, e.g. \u201canimal\u201d in the \u201cpython (animal)\u201d. However, neither hypernyms nor rules for their automatic extraction are available for all 158 languages. Therefore, we use a simpler method to select a keyword which would help to interpret each cluster. For each graph node $v \\in V$ we count the number of anti-edges it belongs to: $count(v) = | \\lbrace (w_i,\\overline{w_i}) : (w_i,\\overline{w_i}) \\in \\overline{E} \\wedge (v = w_i \\vee v = \\overline{w_i}) \\rbrace |$. A graph clustering yields a partition of $V$ into $n$ clusters: $V~=~\\lbrace V_1, V_2, ..., V_n\\rbrace $. For each cluster $V_i$ we define a keyword $w^{key}_i$ as the word with the largest number of anti-edges $count(\\cdot )$ among words in this cluster."
|
| 97 |
+
],
|
| 98 |
+
[
|
| 99 |
+
"We use keywords defined above to obtain vector representations of senses. In particular, we simply use word embedding of the keyword $w^{key}_i$ as a sense representation $\\mathbf {s}_i$ of the target word $w$ to avoid explicit computation of sense embeddings like in BIBREF19. Given a sentence $\\lbrace w_1, w_2, ..., w_{j}, w, w_{j+1}, ..., w_n\\rbrace $ represented as a matrix of word vectors, we define the context of the target word $w$ as $\\textbf {c}_w = \\dfrac{\\sum _{j=1}^{n} w_j}{n}$. Then, we define the most appropriate sense $\\hat{s}$ as the sense with the highest cosine similarity to the embedding of the word's context:"
|
| 100 |
+
],
|
| 101 |
+
[
|
| 102 |
+
"We release a system for on-the-fly WSD for 158 languages. Given textual input, it identifies polysemous words and retrieves senses that are the most appropriate in the context."
|
| 103 |
+
],
|
| 104 |
+
[
|
| 105 |
+
"To build word sense inventories (sense vectors) for 158 languages, we utilised GPU-accelerated routines for search of similar vectors implemented in Faiss library BIBREF27. The search of nearest neighbours takes substantial time, therefore, acceleration with GPUs helps to significantly reduce the word sense construction time. To further speed up the process, we keep all intermediate results in memory, which results in substantial RAM consumption of up to 200 Gb.",
|
| 106 |
+
"The construction of word senses for all of the 158 languages takes a lot of computational resources and imposes high requirements to the hardware. For calculations, we use in parallel 10\u201320 nodes of the Zhores cluster BIBREF28 empowered with Nvidia Tesla V100 graphic cards. For each of the languages, we construct inventories based on 50, 100, and 200 neighbours for 100,000 most frequent words. The vocabulary was limited in order to make the computation time feasible. The construction of inventories for one language takes up to 10 hours, with $6.5$ hours on average. Building the inventories for all languages took more than 1,000 hours of GPU-accelerated computations. We release the constructed sense inventories for all the available languages. They contain all the necessary information for using them in the proposed WSD system or in other downstream tasks."
|
| 107 |
+
],
|
| 108 |
+
[
|
| 109 |
+
"The first text pre-processing step is language identification, for which we use the fastText language identification models by Bojanowski:17. Then the input is tokenised. For languages which use Latin, Cyrillic, Hebrew, or Greek scripts, we employ the Europarl tokeniser. For Chinese, we use the Stanford Word Segmenter BIBREF29. For Japanese, we use Mecab BIBREF30. We tokenise Vietnamese with UETsegmenter BIBREF31. All other languages are processed with the ICU tokeniser, as implemented in the PyICU project. After the tokenisation, the system analyses all the input words with pre-extracted sense inventories and defines the most appropriate sense for polysemous words.",
|
| 110 |
+
"Figure FIGREF19 shows the interface of the system. It has a textual input form. The automatically identified language of text is shown above. A click on any of the words displays a prompt (shown in black) with the most appropriate sense of a word in the specified context and the confidence score. In the given example, the word Jaguar is correctly identified as a car brand. This system is based on the system by Ustalov:18, extending it with a back-end for multiple languages, language detection, and sense browsing capabilities."
|
| 111 |
+
],
|
| 112 |
+
[
|
| 113 |
+
"We first evaluate our converted embedding models on multi-language lexical similarity and relatedness tasks, as a sanity check, to make sure the word sense induction process did not hurt the general performance of the embeddings. Then, we test the sense embeddings on WSD task."
|
| 114 |
+
],
|
| 115 |
+
[
|
| 116 |
+
"We use the SemR-11 datasets BIBREF32, which contain word pairs with manually assigned similarity scores from 0 (words are not related) to 10 (words are fully interchangeable) for 12 languages: English (en), Arabic (ar), German (de), Spanish (es), Farsi (fa), French (fr), Italian (it), Dutch (nl), Portuguese (pt), Russian (ru), Swedish (sv), Chinese (zh). The task is to assign relatedness scores to these pairs so that the ranking of the pairs by this score is close to the ranking defined by the oracle score. The performance is measured with Pearson correlation of the rankings. Since one word can have several different senses in our setup, we follow Remus:18 and define the relatedness score for a pair of words as the maximum cosine similarity between any of their sense vectors.",
|
| 117 |
+
"We extract the sense inventories from fastText embedding vectors. We set $N=K$ for all our experiments, i.e. the number of vertices in the graph and the maximum number of vertices' nearest neighbours match. We conduct experiments with $N=K$ set to 50, 100, and 200. For each cluster $V_i$ we create a sense vector $s_i$ by averaging vectors that belong to this cluster. We rely on the methodology of BIBREF33 shifting the generated sense vector to the direction of the original word vector: $s_i~=~\\lambda ~w + (1-\\lambda )~\\dfrac{1}{n}~\\sum _{u~\\in ~V_i} cos(w, u)\\cdot u, $ where, $\\lambda \\in [0, 1]$, $w$ is the embedding of the original word, $cos(w, u)$ is the cosine similarity between $w$ and $u$, and $n=|V_i|$. By introducing the linear combination of $w$ and $u~\\in ~V_i$ we enforce the similarity of sense vectors to the original word important for this task. In addition to that, we weight $u$ by their similarity to the original word, so that more similar neighbours contribute more to the sense vector. The shifting parameter $\\lambda $ is set to $0.5$, following Remus:18.",
|
| 118 |
+
"A fastText model is able to generate a vector for each word even if it is not represented in the vocabulary, due to the use of subword information. However, our system cannot assemble sense vectors for out-of-vocabulary words, for such words it returns their original fastText vector. Still, the coverage of the benchmark datasets by our vocabulary is at least 85% and approaches 100% for some languages, so we do not have to resort to this back-off strategy very often.",
|
| 119 |
+
"We use the original fastText vectors as a baseline. In this case, we compute the relatedness scores of the two words as a cosine similarity of their vectors."
|
| 120 |
+
],
|
| 121 |
+
[
|
| 122 |
+
"We compute the relatedness scores for all benchmark datasets using our sense vectors and compare them to cosine similarity scores of original fastText vectors. The results vary for different languages. Figure FIGREF28 shows the change in Pearson correlation score when switching from the baseline fastText embeddings to our sense vectors. The new vectors significantly improve the relatedness detection for German, Farsi, Russian, and Chinese, whereas for Italian, Dutch, and Swedish the score slightly falls behind the baseline. For other languages, the performance of sense vectors is on par with regular fastText."
|
| 123 |
+
],
|
| 124 |
+
[
|
| 125 |
+
"The purpose of our sense vectors is disambiguation of polysemous words. Therefore, we test the inventories constructed with egvi on the Task 13 of SemEval-2013 \u2014 Word Sense Induction BIBREF34. The task is to identify the different senses of a target word in context in a fully unsupervised manner."
|
| 126 |
+
],
|
| 127 |
+
[
|
| 128 |
+
"The dataset consists of a set of polysemous words: 20 nouns, 20 verbs, and 10 adjectives and specifies 20 to 100 contexts per word, with the total of 4,664 contexts, drawn from the Open American National Corpus. Given a set of contexts of a polysemous word, the participants of the competition had to divide them into clusters by sense of the word. The contexts are manually labelled with WordNet senses of the target words, the gold standard clustering is generated from this labelling.",
|
| 129 |
+
"The task allows two setups: graded WSI where participants can submit multiple senses per word and provide the probability of each sense in a particular context, and non-graded WSI where a model determines a single sense for a word in context. In our experiments we performed non-graded WSI. We considered the most suitable sense as the one with the highest cosine similarity with embeddings of the context, as described in Section SECREF9.",
|
| 130 |
+
"The performance of WSI models is measured with three metrics that require mapping of sense inventories (Jaccard Index, Kendall's $\\tau $, and WNDCG) and two cluster comparison metrics (Fuzzy NMI and Fuzzy B-Cubed)."
|
| 131 |
+
],
|
| 132 |
+
[
|
| 133 |
+
"We compare our model with the models that participated in the task, the baseline ego-graph clustering model by Pelevina:16, and AdaGram BIBREF17, a method that learns sense embeddings based on a Bayesian extension of the Skip-gram model. Besides that, we provide the scores of the simple baselines originally used in the task: assigning one sense to all words, assigning the most frequent sense to all words, and considering each context as expressing a different sense. The evaluation of our model was performed using the open source context-eval tool.",
|
| 134 |
+
"Table TABREF31 shows the performance of these models on the SemEval dataset. Due to space constraints, we only report the scores of the best-performing SemEval participants, please refer to jurgens-klapaftis-2013-semeval for the full results. The performance of AdaGram and SenseGram models is reported according to Pelevina:16.",
|
| 135 |
+
"The table shows that the performance of egvi is similar to state-of-the-art word sense disambiguation and word sense induction models. In particular, we can see that it outperforms SenseGram on the majority of metrics. We should note that this comparison is not fully rigorous, because SenseGram induces sense inventories from word2vec as opposed to fastText vectors used in our work."
|
| 136 |
+
],
|
| 137 |
+
[
|
| 138 |
+
"In order to see how the separation of word contexts that we perform corresponds to actual senses of polysemous words, we visualise ego-graphs produced by our method. Figure FIGREF17 shows the nearest neighbours clustering for the word Ruby, which divides the graph into five senses: Ruby-related programming tools, e.g. RubyOnRails (orange cluster), female names, e.g. Josie (magenta cluster), gems, e.g. Sapphire (yellow cluster), programming languages in general, e.g. Haskell (red cluster). Besides, this is typical for fastText embeddings featuring sub-string similarity, one can observe a cluster of different spelling of the word Ruby in green.",
|
| 139 |
+
"Analogously, the word python (see Figure FIGREF35) is divided into the senses of animals, e.g. crocodile (yellow cluster), programming languages, e.g. perl5 (magenta cluster), and conference, e.g. pycon (red cluster).",
|
| 140 |
+
"In addition, we show a qualitative analysis of senses of mouse and apple. Table TABREF38 shows nearest neighbours of the original words separated into clusters (labels for clusters were assigned manually). These inventories demonstrate clear separation of different senses, although it can be too fine-grained. For example, the first and the second cluster for mouse both refer to computer mouse, but the first one addresses the different types of computer mice, and the second one is used in the context of mouse actions. Similarly, we see that iphone and macbook are separated into two clusters. Interestingly, fastText handles typos, code-switching, and emojis by correctly associating all non-standard variants to the word they refer, and our method is able to cluster them appropriately. Both inventories were produced with $K=200$, which ensures stronger connectivity of graph. However, we see that this setting still produces too many clusters. We computed the average numbers of clusters produced by our model with $K=200$ for words from the word relatedness datasets and compared these numbers with the number of senses in WordNet for English and RuWordNet BIBREF35 for Russian (see Table TABREF37). We can see that the number of senses extracted by our method is consistently higher than the real number of senses.",
|
| 141 |
+
"We also compute the average number of senses per word for all the languages and different values of $K$ (see Figure FIGREF36). The average across languages does not change much as we increase $K$. However, for larger $K$ the average exceed the median value, indicating that more languages have lower number of senses per word. At the same time, while at smaller $K$ the maximum average number of senses per word does not exceed 6, larger values of $K$ produce outliers, e.g. English with $12.5$ senses.",
|
| 142 |
+
"Notably, there are no languages with an average number of senses less than 2, while numbers on English and Russian WordNets are considerably lower. This confirms that our method systematically over-generates senses. The presence of outliers shows that this effect cannot be eliminated by further increasing $K$, because the $i$-th nearest neighbour of a word for $i>200$ can be only remotely related to this word, even if the word is rare. Thus, our sense clustering algorithm needs a method of merging spurious senses."
|
| 143 |
+
],
|
| 144 |
+
[
|
| 145 |
+
"We present egvi, a new algorithm for word sense induction based on graph clustering that is fully unsupervised and relies on graph operations between word vectors. We apply this algorithm to a large collection of pre-trained fastText word embeddings, releasing sense inventories for 158 languages. These inventories contain all the necessary information for constructing sense vectors and using them in downstream tasks. The sense vectors for polysemous words can be directly retrofitted with the pre-trained word embeddings and do not need any external resources. As one application of these multilingual sense inventories, we present a multilingual word sense disambiguation system that performs unsupervised and knowledge-free WSD for 158 languages without the use of any dictionary or sense-labelled corpus.",
|
| 146 |
+
"The evaluation of quality of the produced sense inventories is performed on multilingual word similarity benchmarks, showing that our sense vectors improve the scores compared to non-disambiguated word embeddings. Therefore, our system in its present state can improve WSD and downstream tasks for languages where knowledge bases, taxonomies, and annotated corpora are not available and supervised WSD models cannot be trained.",
|
| 147 |
+
"A promising direction for future work is combining distributional information from the induced sense inventories with lexical knowledge bases to improve WSD performance. Besides, we encourage the use of the produced word sense inventories in other downstream tasks."
|
| 148 |
+
],
|
| 149 |
+
[
|
| 150 |
+
"We acknowledge the support of the Deutsche Forschungsgemeinschaft (DFG) foundation under the \u201cJOIN-T 2\u201d and \u201cACQuA\u201d projects. Ekaterina Artemova was supported by the framework of the HSE University Basic Research Program and Russian Academic Excellence Project \u201c5-100\u201d."
|
| 151 |
+
]
|
| 152 |
+
]
|
| 153 |
+
}
|
| 154 |
+
```
|
qasper-0067/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
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|
| 1 |
+
Name of Paper: Word Sense Disambiguation for 158 Languages using Word Embeddings Only
|
| 2 |
+
|
| 3 |
+
Question: How are the different senses annotated/labeled?
|
qasper-0068/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: Word Sense Disambiguation for 158 Languages using Word Embeddings Only
|
| 2 |
+
|
| 3 |
+
Question: Was any extrinsic evaluation carried out?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"",
|
| 11 |
+
" ::: ",
|
| 12 |
+
" ::: ::: ",
|
| 13 |
+
"Introduction",
|
| 14 |
+
"Related Work",
|
| 15 |
+
"Algorithm for Word Sense Induction",
|
| 16 |
+
"Algorithm for Word Sense Induction ::: SenseGram: A Baseline Graph-based Word Sense Induction Algorithm",
|
| 17 |
+
"Algorithm for Word Sense Induction ::: egvi (Ego-Graph Vector Induction): A Novel Word Sense Induction Algorithm ::: Induction of Sense Inventories",
|
| 18 |
+
"Algorithm for Word Sense Induction ::: egvi (Ego-Graph Vector Induction): A Novel Word Sense Induction Algorithm ::: Labelling of Induced Senses",
|
| 19 |
+
"Algorithm for Word Sense Induction ::: egvi (Ego-Graph Vector Induction): A Novel Word Sense Induction Algorithm ::: Word Sense Disambiguation",
|
| 20 |
+
"System Design",
|
| 21 |
+
"System Design ::: Construction of Sense Inventories",
|
| 22 |
+
"System Design ::: Word Sense Disambiguation System",
|
| 23 |
+
"Evaluation",
|
| 24 |
+
"Evaluation ::: Lexical Similarity and Relatedness ::: Experimental Setup",
|
| 25 |
+
"Evaluation ::: Lexical Similarity and Relatedness ::: Discussion of Results",
|
| 26 |
+
"Evaluation ::: Word Sense Disambiguation",
|
| 27 |
+
"Evaluation ::: Word Sense Disambiguation ::: Experimental Setup",
|
| 28 |
+
"Evaluation ::: Word Sense Disambiguation ::: Discussion of Results",
|
| 29 |
+
"Evaluation ::: Analysis",
|
| 30 |
+
"Conclusions and Future Work",
|
| 31 |
+
"Acknowledgements"
|
| 32 |
+
],
|
| 33 |
+
"paragraphs": [
|
| 34 |
+
[
|
| 35 |
+
"1.1em"
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"1.1.1em"
|
| 39 |
+
],
|
| 40 |
+
[
|
| 41 |
+
"1.1.1.1em",
|
| 42 |
+
"ru=russian",
|
| 43 |
+
"",
|
| 44 |
+
"$^1$Skolkovo Institute of Science and Technology, Moscow, Russia",
|
| 45 |
+
"v.logacheva@skoltech.ru",
|
| 46 |
+
"$^2$Ural Federal University, Yekaterinburg, Russia",
|
| 47 |
+
"$^3$Universit\u00e4t Hamburg, Hamburg, Germany",
|
| 48 |
+
"$^4$Universit\u00e4t Mannheim, Mannheim, Germany",
|
| 49 |
+
"$^5$University of Oslo, Oslo, Norway",
|
| 50 |
+
"$^6$Higher School of Economics, Moscow, Russia",
|
| 51 |
+
"Disambiguation of word senses in context is easy for humans, but is a major challenge for automatic approaches. Sophisticated supervised and knowledge-based models were developed to solve this task. However, (i) the inherent Zipfian distribution of supervised training instances for a given word and/or (ii) the quality of linguistic knowledge representations motivate the development of completely unsupervised and knowledge-free approaches to word sense disambiguation (WSD). They are particularly useful for under-resourced languages which do not have any resources for building either supervised and/or knowledge-based models. In this paper, we present a method that takes as input a standard pre-trained word embedding model and induces a fully-fledged word sense inventory, which can be used for disambiguation in context. We use this method to induce a collection of sense inventories for 158 languages on the basis of the original pre-trained fastText word embeddings by Grave:18, enabling WSD in these languages. Models and system are available online.",
|
| 52 |
+
"word sense induction, word sense disambiguation, word embeddings, sense embeddings, graph clustering"
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"There are many polysemous words in virtually any language. If not treated as such, they can hamper the performance of all semantic NLP tasks BIBREF0. Therefore, the task of resolving the polysemy and choosing the most appropriate meaning of a word in context has been an important NLP task for a long time. It is usually referred to as Word Sense Disambiguation (WSD) and aims at assigning meaning to a word in context.",
|
| 56 |
+
"The majority of approaches to WSD are based on the use of knowledge bases, taxonomies, and other external manually built resources BIBREF1, BIBREF2. However, different senses of a polysemous word occur in very diverse contexts and can potentially be discriminated with their help. The fact that semantically related words occur in similar contexts, and diverse words do not share common contexts, is known as distributional hypothesis and underlies the technique of constructing word embeddings from unlabelled texts. The same intuition can be used to discriminate between different senses of individual words. There exist methods of training word embeddings that can detect polysemous words and assign them different vectors depending on their contexts BIBREF3, BIBREF4. Unfortunately, many wide-spread word embedding models, such as GloVe BIBREF5, word2vec BIBREF6, fastText BIBREF7, do not handle polysemous words. Words in these models are represented with single vectors, which were constructed from diverse sets of contexts corresponding to different senses. In such cases, their disambiguation needs knowledge-rich approaches.",
|
| 57 |
+
"We tackle this problem by suggesting a method of post-hoc unsupervised WSD. It does not require any external knowledge and can separate different senses of a polysemous word using only the information encoded in pre-trained word embeddings. We construct a semantic similarity graph for words and partition it into densely connected subgraphs. This partition allows for separating different senses of polysemous words. Thus, the only language resource we need is a large unlabelled text corpus used to train embeddings. This makes our method applicable to under-resourced languages. Moreover, while other methods of unsupervised WSD need to train embeddings from scratch, we perform retrofitting of sense vectors based on existing word embeddings.",
|
| 58 |
+
"We create a massively multilingual application for on-the-fly word sense disambiguation. When receiving a text, the system identifies its language and performs disambiguation of all the polysemous words in it based on pre-extracted word sense inventories. The system works for 158 languages, for which pre-trained fastText embeddings available BIBREF8. The created inventories are based on these embeddings. To the best of our knowledge, our system is the only WSD system for the majority of the presented languages. Although it does not match the state of the art for resource-rich languages, it is fully unsupervised and can be used for virtually any language.",
|
| 59 |
+
"The contributions of our work are the following:",
|
| 60 |
+
"[noitemsep]",
|
| 61 |
+
"We release word sense inventories associated with fastText embeddings for 158 languages.",
|
| 62 |
+
"We release a system that allows on-the-fly word sense disambiguation for 158 languages.",
|
| 63 |
+
"We present egvi (Ego-Graph Vector Induction), a new algorithm of unsupervised word sense induction, which creates sense inventories based on pre-trained word vectors."
|
| 64 |
+
],
|
| 65 |
+
[
|
| 66 |
+
"There are two main scenarios for WSD: the supervised approach that leverages training corpora explicitly labelled for word sense, and the knowledge-based approach that derives sense representation from lexical resources, such as WordNet BIBREF9. In the supervised case WSD can be treated as a classification problem. Knowledge-based approaches construct sense embeddings, i.e. embeddings that separate various word senses.",
|
| 67 |
+
"SupWSD BIBREF10 is a state-of-the-art system for supervised WSD. It makes use of linear classifiers and a number of features such as POS tags, surrounding words, local collocations, word embeddings, and syntactic relations. GlossBERT model BIBREF11, which is another implementation of supervised WSD, achieves a significant improvement by leveraging gloss information. This model benefits from sentence-pair classification approach, introduced by Devlin:19 in their BERT contextualized embedding model. The input to the model consists of a context (a sentence which contains an ambiguous word) and a gloss (sense definition) from WordNet. The context-gloss pair is concatenated through a special token ([SEP]) and classified as positive or negative.",
|
| 68 |
+
"On the other hand, sense embeddings are an alternative to traditional word vector models such as word2vec, fastText or GloVe, which represent monosemous words well but fail for ambiguous words. Sense embeddings represent individual senses of polysemous words as separate vectors. They can be linked to an explicit inventory BIBREF12 or induce a sense inventory from unlabelled data BIBREF13. LSTMEmbed BIBREF13 aims at learning sense embeddings linked to BabelNet BIBREF14, at the same time handling word ordering, and using pre-trained embeddings as an objective. Although it was tested only on English, the approach can be easily adapted to other languages present in BabelNet. However, manually labelled datasets as well as knowledge bases exist only for a small number of well-resourced languages. Thus, to disambiguate polysemous words in other languages one has to resort to fully unsupervised techniques.",
|
| 69 |
+
"The task of Word Sense Induction (WSI) can be seen as an unsupervised version of WSD. WSI aims at clustering word senses and does not require to map each cluster to a predefined sense. Instead of that, word sense inventories are induced automatically from the clusters, treating each cluster as a single sense of a word. WSI approaches fall into three main groups: context clustering, word ego-network clustering and synonyms (or substitute) clustering.",
|
| 70 |
+
"Context clustering approaches consist in creating vectors which characterise words' contexts and clustering these vectors. Here, the definition of context may vary from window-based context to latent topic-alike context. Afterwards, the resulting clusters are either used as senses directly BIBREF15, or employed further to learn sense embeddings via Chinese Restaurant Process algorithm BIBREF16, AdaGram, a Bayesian extension of the Skip-Gram model BIBREF17, AutoSense, an extension of the LDA topic model BIBREF18, and other techniques.",
|
| 71 |
+
"Word ego-network clustering is applied to semantic graphs. The nodes of a semantic graph are words, and edges between them denote semantic relatedness which is usually evaluated with cosine similarity of the corresponding embeddings BIBREF19 or by PMI-like measures BIBREF20. Word senses are induced via graph clustering algorithms, such as Chinese Whispers BIBREF21 or MaxMax BIBREF22. The technique suggested in our work belongs to this class of methods and is an extension of the method presented by Pelevina:16.",
|
| 72 |
+
"Synonyms and substitute clustering approaches create vectors which represent synonyms or substitutes of polysemous words. Such vectors are created using synonymy dictionaries BIBREF23 or context-dependent substitutes obtained from a language model BIBREF24. Analogously to previously described techniques, word senses are induced by clustering these vectors."
|
| 73 |
+
],
|
| 74 |
+
[
|
| 75 |
+
"The majority of word vector models do not discriminate between multiple senses of individual words. However, a polysemous word can be identified via manual analysis of its nearest neighbours\u2014they reflect different senses of the word. Table TABREF7 shows manually sense-labelled most similar terms to the word Ruby according to the pre-trained fastText model BIBREF8. As it was suggested early by Widdows:02, the distributional properties of a word can be used to construct a graph of words that are semantically related to it, and if a word is polysemous, such graph can easily be partitioned into a number of densely connected subgraphs corresponding to different senses of this word. Our algorithm is based on the same principle."
|
| 76 |
+
],
|
| 77 |
+
[
|
| 78 |
+
"SenseGram is the method proposed by Pelevina:16 that separates nearest neighbours to induce word senses and constructs sense embeddings for each sense. It starts by constructing an ego-graph (semantic graph centred at a particular word) of the word and its nearest neighbours. The edges between the words denote their semantic relatedness, e.g. the two nodes are joined with an edge if cosine similarity of the corresponding embeddings is higher than a pre-defined threshold. The resulting graph can be clustered into subgraphs which correspond to senses of the word.",
|
| 79 |
+
"The sense vectors are then constructed by averaging embeddings of words in each resulting cluster. In order to use these sense vectors for word sense disambiguation in text, the authors compute the probabilities of sense vectors of a word given its context or the similarity of the sense vectors to the context."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"One of the downsides of the described above algorithm is noise in the generated graph, namely, unrelated words and wrong connections. They hamper the separation of the graph. Another weak point is the imbalance in the nearest neighbour list, when a large part of it is attributed to the most frequent sense, not sufficiently representing the other senses. This can lead to construction of incorrect sense vectors.",
|
| 83 |
+
"We suggest a more advanced procedure of graph construction that uses the interpretability of vector addition and subtraction operations in word embedding space BIBREF6 while the previous algorithm only relies on the list of nearest neighbours in word embedding space. The key innovation of our algorithm is the use of vector subtraction to find pairs of most dissimilar graph nodes and construct the graph only from the nodes included in such \u201canti-edges\u201d. Thus, our algorithm is based on graph-based word sense induction, but it also relies on vector-based operations between word embeddings to perform filtering of graph nodes. Analogously to the work of Pelevina:16, we construct a semantic relatedness graph from a list of nearest neighbours, but we filter this list using the following procedure:",
|
| 84 |
+
"Extract a list $\\mathcal {N}$ = {$w_{1}$, $w_{2}$, ..., $w_{N}$} of $N$ nearest neighbours for the target (ego) word vector $w$.",
|
| 85 |
+
"Compute a list $\\Delta $ = {$\\delta _{1}$, $\\delta _{2}$, ..., $\\delta _{N}$} for each $w_{i}$ in $\\mathcal {N}$, where $\\delta _{i}~=~w-w_{i}$. The vectors in $\\delta $ contain the components of sense of $w$ which are not related to the corresponding nearest neighbours from $\\mathcal {N}$.",
|
| 86 |
+
"Compute a list $\\overline{\\mathcal {N}}$ = {$\\overline{w_{1}}$, $\\overline{w_{2}}$, ..., $\\overline{w_{N}}$}, such that $\\overline{w_{i}}$ is in the top nearest neighbours of $\\delta _{i}$ in the embedding space. In other words, $\\overline{w_{i}}$ is a word which is the most similar to the target (ego) word $w$ and least similar to its neighbour $w_{i}$. We refer to $\\overline{w_{i}}$ as an anti-pair of $w_{i}$. The set of $N$ nearest neighbours and their anti-pairs form a set of anti-edges i.e. pairs of most dissimilar nodes \u2013 those which should not be connected: $\\overline{E} = \\lbrace (w_{1},\\overline{w_{1}}), (w_{2},\\overline{w_{2}}), ..., (w_{N},\\overline{w_{N}})\\rbrace $.",
|
| 87 |
+
"To clarify this, consider the target (ego) word $w = \\textit {python}$, its top similar term $w_1 = \\textit {Java}$ and the resulting anti-pair $\\overline{w_i} = \\textit {snake}$ which is the top related term of $\\delta _1 = w - w_1$. Together they form an anti-edge $(w_i,\\overline{w_i})=(\\textit {Java}, \\textit {snake})$ composed of a pair of semantically dissimilar terms.",
|
| 88 |
+
"Construct $V$, the set of vertices of our semantic graph $G=(V,E)$ from the list of anti-edges $\\overline{E}$, with the following recurrent procedure: $V = V \\cup \\lbrace w_{i}, \\overline{w_{i}}: w_{i} \\in \\mathcal {N}, \\overline{w_{i}} \\in \\mathcal {N}\\rbrace $, i.e. we add a word from the list of nearest neighbours and its anti-pair only if both of them are nearest neighbours of the original word $w$. We do not add $w$'s nearest neighbours if their anti-pairs do not belong to $\\mathcal {N}$. Thus, we add only words which can help discriminating between different senses of $w$.",
|
| 89 |
+
"Construct the set of edges $E$ as follows. For each $w_{i}~\\in ~\\mathcal {N}$ we extract a set of its $K$ nearest neighbours $\\mathcal {N}^{\\prime }_{i} = \\lbrace u_{1}, u_{2}, ..., u_{K}\\rbrace $ and define $E = \\lbrace (w_{i}, u_{j}): w_{i}~\\in ~V, u_j~\\in ~V, u_{j}~\\in ~\\mathcal {N}^{\\prime }_{i}, u_{j}~\\ne ~\\overline{w_{i}}\\rbrace $. In other words, we remove edges between a word $w_{i}$ and its nearest neighbour $u_j$ if $u_j$ is also its anti-pair. According to our hypothesis, $w_{i}$ and $\\overline{w_{i}}$ belong to different senses of $w$, so they should not be connected (i.e. we never add anti-edges into $E$). Therefore, we consider any connection between them as noise and remove it.",
|
| 90 |
+
"Note that $N$ (the number of nearest neighbours for the target word $w$) and $K$ (the number of nearest neighbours of $w_{ci}$) do not have to match. The difference between these parameters is the following. $N$ defines how many words will be considered for the construction of ego-graph. On the other hand, $K$ defines the degree of relatedness between words in the ego-graph \u2014 if $K = 50$, then we will connect vertices $w$ and $u$ with an edge only if $u$ is in the list of 50 nearest neighbours of $w$. Increasing $K$ increases the graph connectivity and leads to lower granularity of senses.",
|
| 91 |
+
"According to our hypothesis, nearest neighbours of $w$ are grouped into clusters in the vector space, and each of the clusters corresponds to a sense of $w$. The described vertices selection procedure allows picking the most representative members of these clusters which are better at discriminating between the clusters. In addition to that, it helps dealing with the cases when one of the clusters is over-represented in the nearest neighbour list. In this case, many elements of such a cluster are not added to $V$ because their anti-pairs fall outside the nearest neighbour list. This also improves the quality of clustering.",
|
| 92 |
+
"After the graph construction, the clustering is performed using the Chinese Whispers algorithm BIBREF21. This is a bottom-up clustering procedure that does not require to pre-define the number of clusters, so it can correctly process polysemous words with varying numbers of senses as well as unambiguous words.",
|
| 93 |
+
"Figure FIGREF17 shows an example of the resulting pruned graph of for the word Ruby for $N = 50$ nearest neighbours in terms of the fastText cosine similarity. In contrast to the baseline method by BIBREF19 where all 50 terms are clustered, in the method presented in this section we sparsify the graph by removing 13 nodes which were not in the set of the \u201canti-edges\u201d i.e. pairs of most dissimilar terms out of these 50 neighbours. Examples of anti-edges i.e. pairs of most dissimilar terms for this graph include: (Haskell, Sapphire), (Garnet, Rails), (Opal, Rubyist), (Hazel, RubyOnRails), and (Coffeescript, Opal)."
|
| 94 |
+
],
|
| 95 |
+
[
|
| 96 |
+
"We label each word cluster representing a sense to make them and the WSD results interpretable by humans. Prior systems used hypernyms to label the clusters BIBREF25, BIBREF26, e.g. \u201canimal\u201d in the \u201cpython (animal)\u201d. However, neither hypernyms nor rules for their automatic extraction are available for all 158 languages. Therefore, we use a simpler method to select a keyword which would help to interpret each cluster. For each graph node $v \\in V$ we count the number of anti-edges it belongs to: $count(v) = | \\lbrace (w_i,\\overline{w_i}) : (w_i,\\overline{w_i}) \\in \\overline{E} \\wedge (v = w_i \\vee v = \\overline{w_i}) \\rbrace |$. A graph clustering yields a partition of $V$ into $n$ clusters: $V~=~\\lbrace V_1, V_2, ..., V_n\\rbrace $. For each cluster $V_i$ we define a keyword $w^{key}_i$ as the word with the largest number of anti-edges $count(\\cdot )$ among words in this cluster."
|
| 97 |
+
],
|
| 98 |
+
[
|
| 99 |
+
"We use keywords defined above to obtain vector representations of senses. In particular, we simply use word embedding of the keyword $w^{key}_i$ as a sense representation $\\mathbf {s}_i$ of the target word $w$ to avoid explicit computation of sense embeddings like in BIBREF19. Given a sentence $\\lbrace w_1, w_2, ..., w_{j}, w, w_{j+1}, ..., w_n\\rbrace $ represented as a matrix of word vectors, we define the context of the target word $w$ as $\\textbf {c}_w = \\dfrac{\\sum _{j=1}^{n} w_j}{n}$. Then, we define the most appropriate sense $\\hat{s}$ as the sense with the highest cosine similarity to the embedding of the word's context:"
|
| 100 |
+
],
|
| 101 |
+
[
|
| 102 |
+
"We release a system for on-the-fly WSD for 158 languages. Given textual input, it identifies polysemous words and retrieves senses that are the most appropriate in the context."
|
| 103 |
+
],
|
| 104 |
+
[
|
| 105 |
+
"To build word sense inventories (sense vectors) for 158 languages, we utilised GPU-accelerated routines for search of similar vectors implemented in Faiss library BIBREF27. The search of nearest neighbours takes substantial time, therefore, acceleration with GPUs helps to significantly reduce the word sense construction time. To further speed up the process, we keep all intermediate results in memory, which results in substantial RAM consumption of up to 200 Gb.",
|
| 106 |
+
"The construction of word senses for all of the 158 languages takes a lot of computational resources and imposes high requirements to the hardware. For calculations, we use in parallel 10\u201320 nodes of the Zhores cluster BIBREF28 empowered with Nvidia Tesla V100 graphic cards. For each of the languages, we construct inventories based on 50, 100, and 200 neighbours for 100,000 most frequent words. The vocabulary was limited in order to make the computation time feasible. The construction of inventories for one language takes up to 10 hours, with $6.5$ hours on average. Building the inventories for all languages took more than 1,000 hours of GPU-accelerated computations. We release the constructed sense inventories for all the available languages. They contain all the necessary information for using them in the proposed WSD system or in other downstream tasks."
|
| 107 |
+
],
|
| 108 |
+
[
|
| 109 |
+
"The first text pre-processing step is language identification, for which we use the fastText language identification models by Bojanowski:17. Then the input is tokenised. For languages which use Latin, Cyrillic, Hebrew, or Greek scripts, we employ the Europarl tokeniser. For Chinese, we use the Stanford Word Segmenter BIBREF29. For Japanese, we use Mecab BIBREF30. We tokenise Vietnamese with UETsegmenter BIBREF31. All other languages are processed with the ICU tokeniser, as implemented in the PyICU project. After the tokenisation, the system analyses all the input words with pre-extracted sense inventories and defines the most appropriate sense for polysemous words.",
|
| 110 |
+
"Figure FIGREF19 shows the interface of the system. It has a textual input form. The automatically identified language of text is shown above. A click on any of the words displays a prompt (shown in black) with the most appropriate sense of a word in the specified context and the confidence score. In the given example, the word Jaguar is correctly identified as a car brand. This system is based on the system by Ustalov:18, extending it with a back-end for multiple languages, language detection, and sense browsing capabilities."
|
| 111 |
+
],
|
| 112 |
+
[
|
| 113 |
+
"We first evaluate our converted embedding models on multi-language lexical similarity and relatedness tasks, as a sanity check, to make sure the word sense induction process did not hurt the general performance of the embeddings. Then, we test the sense embeddings on WSD task."
|
| 114 |
+
],
|
| 115 |
+
[
|
| 116 |
+
"We use the SemR-11 datasets BIBREF32, which contain word pairs with manually assigned similarity scores from 0 (words are not related) to 10 (words are fully interchangeable) for 12 languages: English (en), Arabic (ar), German (de), Spanish (es), Farsi (fa), French (fr), Italian (it), Dutch (nl), Portuguese (pt), Russian (ru), Swedish (sv), Chinese (zh). The task is to assign relatedness scores to these pairs so that the ranking of the pairs by this score is close to the ranking defined by the oracle score. The performance is measured with Pearson correlation of the rankings. Since one word can have several different senses in our setup, we follow Remus:18 and define the relatedness score for a pair of words as the maximum cosine similarity between any of their sense vectors.",
|
| 117 |
+
"We extract the sense inventories from fastText embedding vectors. We set $N=K$ for all our experiments, i.e. the number of vertices in the graph and the maximum number of vertices' nearest neighbours match. We conduct experiments with $N=K$ set to 50, 100, and 200. For each cluster $V_i$ we create a sense vector $s_i$ by averaging vectors that belong to this cluster. We rely on the methodology of BIBREF33 shifting the generated sense vector to the direction of the original word vector: $s_i~=~\\lambda ~w + (1-\\lambda )~\\dfrac{1}{n}~\\sum _{u~\\in ~V_i} cos(w, u)\\cdot u, $ where, $\\lambda \\in [0, 1]$, $w$ is the embedding of the original word, $cos(w, u)$ is the cosine similarity between $w$ and $u$, and $n=|V_i|$. By introducing the linear combination of $w$ and $u~\\in ~V_i$ we enforce the similarity of sense vectors to the original word important for this task. In addition to that, we weight $u$ by their similarity to the original word, so that more similar neighbours contribute more to the sense vector. The shifting parameter $\\lambda $ is set to $0.5$, following Remus:18.",
|
| 118 |
+
"A fastText model is able to generate a vector for each word even if it is not represented in the vocabulary, due to the use of subword information. However, our system cannot assemble sense vectors for out-of-vocabulary words, for such words it returns their original fastText vector. Still, the coverage of the benchmark datasets by our vocabulary is at least 85% and approaches 100% for some languages, so we do not have to resort to this back-off strategy very often.",
|
| 119 |
+
"We use the original fastText vectors as a baseline. In this case, we compute the relatedness scores of the two words as a cosine similarity of their vectors."
|
| 120 |
+
],
|
| 121 |
+
[
|
| 122 |
+
"We compute the relatedness scores for all benchmark datasets using our sense vectors and compare them to cosine similarity scores of original fastText vectors. The results vary for different languages. Figure FIGREF28 shows the change in Pearson correlation score when switching from the baseline fastText embeddings to our sense vectors. The new vectors significantly improve the relatedness detection for German, Farsi, Russian, and Chinese, whereas for Italian, Dutch, and Swedish the score slightly falls behind the baseline. For other languages, the performance of sense vectors is on par with regular fastText."
|
| 123 |
+
],
|
| 124 |
+
[
|
| 125 |
+
"The purpose of our sense vectors is disambiguation of polysemous words. Therefore, we test the inventories constructed with egvi on the Task 13 of SemEval-2013 \u2014 Word Sense Induction BIBREF34. The task is to identify the different senses of a target word in context in a fully unsupervised manner."
|
| 126 |
+
],
|
| 127 |
+
[
|
| 128 |
+
"The dataset consists of a set of polysemous words: 20 nouns, 20 verbs, and 10 adjectives and specifies 20 to 100 contexts per word, with the total of 4,664 contexts, drawn from the Open American National Corpus. Given a set of contexts of a polysemous word, the participants of the competition had to divide them into clusters by sense of the word. The contexts are manually labelled with WordNet senses of the target words, the gold standard clustering is generated from this labelling.",
|
| 129 |
+
"The task allows two setups: graded WSI where participants can submit multiple senses per word and provide the probability of each sense in a particular context, and non-graded WSI where a model determines a single sense for a word in context. In our experiments we performed non-graded WSI. We considered the most suitable sense as the one with the highest cosine similarity with embeddings of the context, as described in Section SECREF9.",
|
| 130 |
+
"The performance of WSI models is measured with three metrics that require mapping of sense inventories (Jaccard Index, Kendall's $\\tau $, and WNDCG) and two cluster comparison metrics (Fuzzy NMI and Fuzzy B-Cubed)."
|
| 131 |
+
],
|
| 132 |
+
[
|
| 133 |
+
"We compare our model with the models that participated in the task, the baseline ego-graph clustering model by Pelevina:16, and AdaGram BIBREF17, a method that learns sense embeddings based on a Bayesian extension of the Skip-gram model. Besides that, we provide the scores of the simple baselines originally used in the task: assigning one sense to all words, assigning the most frequent sense to all words, and considering each context as expressing a different sense. The evaluation of our model was performed using the open source context-eval tool.",
|
| 134 |
+
"Table TABREF31 shows the performance of these models on the SemEval dataset. Due to space constraints, we only report the scores of the best-performing SemEval participants, please refer to jurgens-klapaftis-2013-semeval for the full results. The performance of AdaGram and SenseGram models is reported according to Pelevina:16.",
|
| 135 |
+
"The table shows that the performance of egvi is similar to state-of-the-art word sense disambiguation and word sense induction models. In particular, we can see that it outperforms SenseGram on the majority of metrics. We should note that this comparison is not fully rigorous, because SenseGram induces sense inventories from word2vec as opposed to fastText vectors used in our work."
|
| 136 |
+
],
|
| 137 |
+
[
|
| 138 |
+
"In order to see how the separation of word contexts that we perform corresponds to actual senses of polysemous words, we visualise ego-graphs produced by our method. Figure FIGREF17 shows the nearest neighbours clustering for the word Ruby, which divides the graph into five senses: Ruby-related programming tools, e.g. RubyOnRails (orange cluster), female names, e.g. Josie (magenta cluster), gems, e.g. Sapphire (yellow cluster), programming languages in general, e.g. Haskell (red cluster). Besides, this is typical for fastText embeddings featuring sub-string similarity, one can observe a cluster of different spelling of the word Ruby in green.",
|
| 139 |
+
"Analogously, the word python (see Figure FIGREF35) is divided into the senses of animals, e.g. crocodile (yellow cluster), programming languages, e.g. perl5 (magenta cluster), and conference, e.g. pycon (red cluster).",
|
| 140 |
+
"In addition, we show a qualitative analysis of senses of mouse and apple. Table TABREF38 shows nearest neighbours of the original words separated into clusters (labels for clusters were assigned manually). These inventories demonstrate clear separation of different senses, although it can be too fine-grained. For example, the first and the second cluster for mouse both refer to computer mouse, but the first one addresses the different types of computer mice, and the second one is used in the context of mouse actions. Similarly, we see that iphone and macbook are separated into two clusters. Interestingly, fastText handles typos, code-switching, and emojis by correctly associating all non-standard variants to the word they refer, and our method is able to cluster them appropriately. Both inventories were produced with $K=200$, which ensures stronger connectivity of graph. However, we see that this setting still produces too many clusters. We computed the average numbers of clusters produced by our model with $K=200$ for words from the word relatedness datasets and compared these numbers with the number of senses in WordNet for English and RuWordNet BIBREF35 for Russian (see Table TABREF37). We can see that the number of senses extracted by our method is consistently higher than the real number of senses.",
|
| 141 |
+
"We also compute the average number of senses per word for all the languages and different values of $K$ (see Figure FIGREF36). The average across languages does not change much as we increase $K$. However, for larger $K$ the average exceed the median value, indicating that more languages have lower number of senses per word. At the same time, while at smaller $K$ the maximum average number of senses per word does not exceed 6, larger values of $K$ produce outliers, e.g. English with $12.5$ senses.",
|
| 142 |
+
"Notably, there are no languages with an average number of senses less than 2, while numbers on English and Russian WordNets are considerably lower. This confirms that our method systematically over-generates senses. The presence of outliers shows that this effect cannot be eliminated by further increasing $K$, because the $i$-th nearest neighbour of a word for $i>200$ can be only remotely related to this word, even if the word is rare. Thus, our sense clustering algorithm needs a method of merging spurious senses."
|
| 143 |
+
],
|
| 144 |
+
[
|
| 145 |
+
"We present egvi, a new algorithm for word sense induction based on graph clustering that is fully unsupervised and relies on graph operations between word vectors. We apply this algorithm to a large collection of pre-trained fastText word embeddings, releasing sense inventories for 158 languages. These inventories contain all the necessary information for constructing sense vectors and using them in downstream tasks. The sense vectors for polysemous words can be directly retrofitted with the pre-trained word embeddings and do not need any external resources. As one application of these multilingual sense inventories, we present a multilingual word sense disambiguation system that performs unsupervised and knowledge-free WSD for 158 languages without the use of any dictionary or sense-labelled corpus.",
|
| 146 |
+
"The evaluation of quality of the produced sense inventories is performed on multilingual word similarity benchmarks, showing that our sense vectors improve the scores compared to non-disambiguated word embeddings. Therefore, our system in its present state can improve WSD and downstream tasks for languages where knowledge bases, taxonomies, and annotated corpora are not available and supervised WSD models cannot be trained.",
|
| 147 |
+
"A promising direction for future work is combining distributional information from the induced sense inventories with lexical knowledge bases to improve WSD performance. Besides, we encourage the use of the produced word sense inventories in other downstream tasks."
|
| 148 |
+
],
|
| 149 |
+
[
|
| 150 |
+
"We acknowledge the support of the Deutsche Forschungsgemeinschaft (DFG) foundation under the \u201cJOIN-T 2\u201d and \u201cACQuA\u201d projects. Ekaterina Artemova was supported by the framework of the HSE University Basic Research Program and Russian Academic Excellence Project \u201c5-100\u201d."
|
| 151 |
+
]
|
| 152 |
+
]
|
| 153 |
+
}
|
| 154 |
+
```
|
qasper-0069/instruction.md
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|
| 1 |
+
Name of Paper: Spoken Language Identification using ConvNets
|
| 2 |
+
|
| 3 |
+
Question: Does the model use both spectrogram images and raw waveforms as features?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Related Work",
|
| 12 |
+
"Proposed Method ::: Motivations",
|
| 13 |
+
"Proposed Method ::: Description of Features",
|
| 14 |
+
"Proposed Method ::: Model Description",
|
| 15 |
+
"Proposed Method ::: Model Details: 1D ConvNet",
|
| 16 |
+
"Proposed Method ::: Model Details: 1D ConvNet ::: Hyperparameter Optimization:",
|
| 17 |
+
"Proposed Method ::: Model Details: 2D ConvNet with Attention and bi-directional GRU",
|
| 18 |
+
"Proposed Method ::: Model Details: 2D ConvNet with Attention and bi-directional GRU ::: ",
|
| 19 |
+
"Proposed Method ::: Model Details: 2D ConvNet with Attention and bi-directional GRU ::: Hyperparameter Optimization:",
|
| 20 |
+
"Proposed Method ::: Model details: 2D-ConvNet",
|
| 21 |
+
"Proposed Method ::: Dataset",
|
| 22 |
+
"Results and Discussion",
|
| 23 |
+
"Results and Discussion ::: Misclassification",
|
| 24 |
+
"Results and Discussion ::: Future Scope",
|
| 25 |
+
"Conclusion"
|
| 26 |
+
],
|
| 27 |
+
"paragraphs": [
|
| 28 |
+
[
|
| 29 |
+
"Language Identification (LI) is a problem which involves classifying the language being spoken by a speaker. LI systems can be used in call centers to route international calls to an operator who is fluent in that identified language BIBREF0. In speech-based assistants, LI acts as the first step which chooses the corresponding grammar from a list of available languages for its further semantic analysis BIBREF1. It can also be used in multi-lingual voice-controlled information retrieval systems, for example, Apple Siri and Amazon Alexa.",
|
| 30 |
+
"Over the years, studies have utilized many prosodic and acoustic features to construct machine learning models for LI systems BIBREF2. Every language is composed of phonemes, which are distinct unit of sounds in that language, such as b of black and g of green. Several prosodic and acoustic features are based on phonemes, which become the underlying features on whom the performance of the statistical model depends BIBREF3, BIBREF4. If two languages have many overlapping phonemes, then identifying them becomes a challenging task for a classifier. For example, the word cat in English, kat in Dutch, katze in German have different consonants but when used in a speech they all would sound quite similar.",
|
| 31 |
+
"Due to such drawbacks several studies have switched over to using Deep Neural Networks (DNNs) to harness their novel auto-extraction techniques BIBREF1, BIBREF5. This work follows an implicit approach for identifying six languages with overlapping phonemes on the VoxForge BIBREF6 dataset and achieves 95.4% overall accuracy.",
|
| 32 |
+
"In previous studies BIBREF1, BIBREF7, BIBREF5, authors use log-Mel spectrum of a raw audio as inputs to their models. One of our contributions is to enhance the performance of this approach by utilising recent techniques like Mixup augmentation of inputs and exploring the effectiveness of Attention mechanism in enhancing performance of neural network. As log-Mel spectrum needs to be computed for each raw audio input and processing time for generating log-Mel spectrum increases linearly with length of audio, this acts as a bottleneck for these models. Hence, we propose the use of raw audio waveforms as inputs to deep neural network which boosts performance by avoiding additional overhead of computing log-Mel spectrum for each audio. Our 1D-ConvNet architecture auto-extracts and classifies features from this raw audio input.",
|
| 33 |
+
"The structure of the work is as follows. In Section 2 we discuss about the previous related studies in this field. The model architecture for both the raw waveforms and log-Mel spectrogram images is discussed in Section 3 along with the a discussion on hyperparameter space exploration. In Section 4 we present the experimental results. Finally, in Section 5 we discuss the conclusions drawn from the experiment and future work."
|
| 34 |
+
],
|
| 35 |
+
[
|
| 36 |
+
"Extraction of language dependent features like prosody and phonemes was a popular approach to classify spoken languages BIBREF8, BIBREF9, BIBREF10. Following their success in speaker verification systems, i-vectors have also been used as features in various classification networks. These approaches required significant domain knowledge BIBREF11, BIBREF9. Nowadays most of the attempts on spoken language identification rely on neural networks for meaningful feature extraction and classification BIBREF12, BIBREF13.",
|
| 37 |
+
"Revay et al. BIBREF5 used the ResNet50 BIBREF14 architecture for classifying languages by generating the log-Mel spectra of each raw audio. The model uses a cyclic learning rate where learning rate increases and then decreases linearly. Maximum learning rate for a cycle is set by finding the optimal learning rate using fastai BIBREF15 library. The model classified six languages \u2013 English, French, Spanish, Russian, Italian and German \u2013 and achieving an accuracy of 89.0%.",
|
| 38 |
+
"Gazeau et al. BIBREF16 in his research showed how Neural Networks, Support Vector Machine and Hidden Markov Model (HMM) can be used to identify French, English, Spanish and German. Dataset was prepared using voice samples from Youtube News BIBREF17and VoxForge BIBREF6 datasets. Hidden Markov models convert speech into a sequence of vectors, was used to capture temporal features in speech. HMMs trained on VoxForge BIBREF6 dataset performed best in comparison to other models proposed by him on same VoxForge dataset. They reported an accuracy of 70.0%.",
|
| 39 |
+
"Bartz et al. BIBREF1 proposed two different hybrid Convolutional Recurrent Neural Networks for language identification. They proposed a new architecture for extracting spatial features from log-Mel spectra of raw audio using CNNs and then using RNNs for capturing temporal features to identify the language. This model achieved an accuracy of 91.0% on Youtube News Dataset BIBREF17. In their second architecture they used the Inception-v3 BIBREF18 architecture to extract spatial features which were then used as input for bi-directional LSTMs to predict the language accurately. This model achieved an accuracy of 96.0% on four languages which were English, German, French and Spanish. They also trained their CNN model (obtained after removing RNN from CRNN model) and the Inception-v3 on their dataset. However they were not able to achieve better results achieving and reported 90% and 95% accuracies, respectively.",
|
| 40 |
+
"Kumar et al. BIBREF0 used Mel-frequency cepstral coefficients (MFCC), Perceptual linear prediction coefficients (PLP), Bark Frequency Cepstral Coefficients (BFCC) and Revised Perceptual Linear Prediction Coefficients (RPLP) as features for language identification. BFCC and RPLP are hybrid features derived using MFCC and PLP. They used two different models based on Vector Quantization (VQ) with Dynamic Time Warping (DTW) and Gaussian Mixture Model (GMM) for classification. These classification models were trained with different features. The authors were able to show that these models worked better with hybrid features (BFCC and RPLP) as compared to conventional features (MFCC and PLP). GMM combined with RPLP features gave the most promising results and achieved an accuracy of 88.8% on ten languages. They designed their own dataset comprising of ten languages being Dutch, English, French, German, Italian, Russian, Spanish, Hindi, Telegu, and Bengali.",
|
| 41 |
+
"Montavon BIBREF7 generated Mel spectrogram as features for a time-delay neural network (TDNN). This network had two-dimensional convolutional layers for feature extraction. An elaborate analysis of how deep architectures outperform their shallow counterparts is presented in this reseacrch. The difficulties in classifying perceptually similar languages like German and English were also put forward in this work. It is mentioned that the proposed approach is less robust to new speakers present in the test dataset. This method was able to achieve an accuracy of 91.2% on dataset comprising of 3 languages \u2013 English, French and German.",
|
| 42 |
+
"In Table TABREF1, we summarize the quantitative results of the above previous studies. It includes the model basis, feature description, languages classified and the used dataset along with accuracy obtained. The table also lists the overall results of our proposed models (at the top). The languages used by various authors along with their acronyms are English (En), Spanish (Es), French (Fr), German (De), Russian (Ru), Italian (It), Bengali (Ben), Hindi (Hi) and Telegu (Tel)."
|
| 43 |
+
],
|
| 44 |
+
[
|
| 45 |
+
"Several state-of-the-art results on various audio classification tasks have been obtained by using log-Mel spectrograms of raw audio, as features BIBREF19. Convolutional Neural Networks have demonstrated an excellent performance gain in classification of these features BIBREF20, BIBREF21 against other machine learning techniques. It has been shown that using attention layers with ConvNets further enhanced their performance BIBREF22. This motivated us to develop a CNN-based architecture with attention since this approach hasn\u2019t been applied to the task of language identification before.",
|
| 46 |
+
"Recently, using raw audio waveform as features to neural networks has become a popular approach in audio classification BIBREF23, BIBREF22. Raw waveforms have several artifacts which are not effectively captured by various conventional feature extraction techniques like Mel Frequency Cepstral Coefficients (MFCC), Constant Q Transform (CQT), Fast Fourier Transform (FFT), etc.",
|
| 47 |
+
"Audio files are a sequence of spoken words, hence they have temporal features too.A CNN is better at capturing spatial features only and RNNs are better at capturing temporal features as demonstrated by Bartz et al. BIBREF1 using audio files. Therefore, we combined both of these to make a CRNN model.",
|
| 48 |
+
"We propose three types of models to tackle the problem with different approaches, discussed as follows."
|
| 49 |
+
],
|
| 50 |
+
[
|
| 51 |
+
"As an average human's voice is around 300 Hz and according to Nyquist-Shannon sampling theorem all the useful frequencies (0-300 Hz) are preserved with sampling at 8 kHz, therefore, we sampled raw audio files from all six languages at 8 kHz",
|
| 52 |
+
"The average length of audio files in this dataset was about 10.4 seconds and standard deviation was 2.3 seconds. For our experiments, the audio length was set to 10 seconds. If the audio files were shorter than 10 second, then the data was repeated and concatenated. If audio files were longer, then the data was truncated."
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"We applied the following design principles to all our models:",
|
| 56 |
+
"Every convolutional layer is always followed by an appropriate max pooling layer. This helps in containing the explosion of parameters and keeps the model small and nimble.",
|
| 57 |
+
"Convolutional blocks are defined as an individual block with multiple pairs of one convolutional layer and one max pooling layer. Each convolutional block is preceded or succeded by a convolutional layer.",
|
| 58 |
+
"Batch Normalization and Rectified linear unit activations were applied after each convolutional layer. Batch Normalization helps speed up convergence during training of a neural network.",
|
| 59 |
+
"Model ends with a dense layer which acts the final output layer."
|
| 60 |
+
],
|
| 61 |
+
[
|
| 62 |
+
"As the sampling rate is 8 kHz and audio length is 10 s, hence the input is raw audio to the models with input size of (batch size, 1, 80000). In Table TABREF10, we present a detailed layer-by-layer illustration of the model along with its hyperparameter.",
|
| 63 |
+
"-10pt"
|
| 64 |
+
],
|
| 65 |
+
[
|
| 66 |
+
"Tuning hyperparameters is a cumbersome process as the hyperparamter space expands exponentially with the number of parameters, therefore efficient exploration is needed for any feasible study. We used the random search algorithm supported by Hyperopt BIBREF24 library to randomly search for an optimal set of hyperparameters from a given parameter space. In Fig. FIGREF12, various hyperparameters we considered are plotted against the validation accuracy as violin plots. Our observations for each hyperparameter are summarized below:",
|
| 67 |
+
"Number of filters in first layer: We observe that having 128 filters gives better results as compared to other filter values of 32 and 64 in the first layer. A higher number of filters in the first layer of network is able to preserve most of the characteristics of input.",
|
| 68 |
+
"Kernel Size: We varied the receptive fields of convolutional layers by choosing the kernel size from among the set of {3, 5, 7, 9}. We observe that a kernel size of 9 gives better accuracy at the cost of increased computation time and larger number of parameters. A large kernel size is able to capture longer patterns in its input due to bigger receptive power which results in an improved accuracy.",
|
| 69 |
+
"Dropout: Dropout randomly turns-off (sets to 0) various individual nodes during training of the network. In a deep CNN it is important that nodes do not develop a co-dependency amongst each other during training in order to prevent overfitting on training data BIBREF25. Dropout rate of $0.1$ works well for our model. When using a higher dropout rate the network is not able to capture the patterns in training dataset.",
|
| 70 |
+
"Batch Size: We chose batch sizes from amongst the set {32, 64, 128}. There is more noise while calculating error in a smaller batch size as compared to a larger one. This tends to have a regularizing effect during training of the network and hence gives better results. Thus, batch size of 32 works best for the model.",
|
| 71 |
+
"Layers in Convolutional block 1 and 2: We varied the number of layers in both the convolutional blocks. If the number of layers is low, then the network does not have enough depth to capture patterns in the data whereas having large number of layers leads to overfitting on the data. In our network, two layers in the first block and one layer in the second block give optimal results."
|
| 72 |
+
],
|
| 73 |
+
[
|
| 74 |
+
"Log-Mel spectrogram is the most commonly used method for converting audio into the image domain. The audio data was again sampled at 8 kHz. The input to this model was the log-Mel spectra. We generated log-Mel spectrogram using the LibROSA BIBREF26 library. In Table TABREF16, we present a detailed layer-by-layer illustration of the model along with its hyperparameter."
|
| 75 |
+
],
|
| 76 |
+
[
|
| 77 |
+
"We took some specific design choices for this model, which are as follows:",
|
| 78 |
+
"We added residual connections with each convolutional layer. Residual connections in a way makes the model selective of the contributing layers, determines the optimal number of layers required for training and solves the problem of vanishing gradients. Residual connections or skip connections skip training of those layers that do not contribute much in the overall outcome of model.",
|
| 79 |
+
"We added spatial attention BIBREF27 networks to help the model in focusing on specific regions or areas in an image. Spatial attention aids learning irrespective of transformations, scaling and rotation done on the input images making the model more robust and helping it to achieve better results.",
|
| 80 |
+
"We added Channel Attention networks so as to help the model to find interdependencies among color channels of log-Mel spectra. It adaptively assigns importance to each color channel in a deep convolutional multi-channel network. In our model we apply channel and spatial attention just before feeding the input into bi-directional GRU. This helps the model to focus on selected regions and at the same time find patterns among channels to better determine the language."
|
| 81 |
+
],
|
| 82 |
+
[
|
| 83 |
+
"We used the random search algorithm supported by Hyperopt BIBREF24 library to randomly search for an optimal set of hyperparameters from a given parameter space. In Fig. FIGREF19 ,various hyperparameters we tuned are plotted against the validation accuracy. Our observations for each hyperparameter are summarized below:",
|
| 84 |
+
"Filter Size: 64 filters in the first layer of network can preserve most of the characteristics of input, but increasing it to 128 is inefficient as overfitting occurs.",
|
| 85 |
+
"Kernel Size: There is a trade-off between kernel size and capturing complex non-linear features. Using a small kernel size will require more layers to capture features whereas using a large kernel size will require less layers. Large kernels capture simple non-linear features whereas using a smaller kernel will help us capture more complex non-linear features. However, with more layers, backpropagation necessitates the need for a large memory. We experimented with large kernel size and gradually increased the layers in order to capture more complex features. The results are not conclusive and thus we chose kernel size of 7 against 3.",
|
| 86 |
+
"Dropout: Dropout rate of 0.1 works well for our data. When using a higher dropout rate the network is not able to capture the patterns in training dataset.",
|
| 87 |
+
"Batch Size: There is always a trade-off between batch size and getting accurate gradients. Using a large batch size helps the model to get more accurate gradients since the model tries to optimize gradients over a large set of images. We found that using a batch size of 128 helped the model to train faster and get better results than using a batch size less than 128.",
|
| 88 |
+
"Number of hidden units in bi-directional GRU: Varying the number of hidden units and layers in GRU helps the model to capture temporal features which can play a significant role in identifying the language correctly. The optimal number of hidden units and layers depends on the complexity of the dataset. Using less number of hidden units may capture less features whereas using large number of hidden units may be computationally expensive. In our case we found that using 1536 hidden units in a single bi-directional GRU layer leads to the best result.",
|
| 89 |
+
"Image Size: We experimented with log-Mel spectra images of sizes $64 \\times 64$ and $128 \\times 128$ pixels and found that our model worked best with images of size of $128 \\times 128$ pixels.",
|
| 90 |
+
"We also evaluated our model on data with mixup augmentation BIBREF28. It is a data augmentation technique that also acts as a regularization technique and prevents overfitting. Instead of directly taking images from the training dataset as input, mixup takes a linear combination of any two random images and feeds it as input. The following equations were used to prepared a mixed-up dataset:",
|
| 91 |
+
"and",
|
| 92 |
+
"where $\\alpha \\in [0, 1]$ is a random variable from a $\\beta $-distribution, $I_1$."
|
| 93 |
+
],
|
| 94 |
+
[
|
| 95 |
+
"This model is a similar model to 2D-ConvNet with Attention and bi-directional GRU described in section SECREF13 except that it lacks skip connections, attention layers, bi-directional GRU and the embedding layer incorporated in the previous model."
|
| 96 |
+
],
|
| 97 |
+
[
|
| 98 |
+
"We classified six languages (English, French, German, Spanish, Russian and Italian) from the VoxForge BIBREF6 dataset. VoxForge is an open-source speech corpus which primarily consists of samples recorded and submitted by users using their own microphone. This results in significant variation of speech quality between samples making it more representative of real world scenarios.",
|
| 99 |
+
"Our dataset consists of 1,500 samples for each of six languages. Out of 1,500 samples for each language, 1,200 were randomly selected as training dataset for that language and rest 300 as validation dataset using k-fold cross-validation. To sum up, we trained our model on 7,200 samples and validated it on 1800 samples comprising six languages. The results are discussed in next section."
|
| 100 |
+
],
|
| 101 |
+
[
|
| 102 |
+
"This paper discusses two end-to-end approaches which achieve state-of-the-art results in both the image as well as audio domain on the VoxForge dataset BIBREF6. In Table TABREF25, we present all the classification accuracies of the two models of the cases with and without mixup for six and four languages.",
|
| 103 |
+
"In the audio domain (using raw audio waveform as input), 1D-ConvNet achieved a mean accuracy of 93.7% with a standard deviation of 0.3% on running k-fold cross validation. In Fig FIGREF27 (a) we present the confusion matrix for the 1D-ConvNet model.",
|
| 104 |
+
"In the image domain (obtained by taking log-Mel spectra of raw audio), 2D-ConvNet with 2D attention (channel and spatial attention) and bi-directional GRU achieved a mean accuracy of 95.0% with a standard deviation of 1.2% for six languages. This model performed better when mixup regularization was applied. 2D-ConvNet achieved a mean accuracy of 95.4% with standard deviation of 0.6% on running k-fold cross validation for six languages when mixup was applied. In Fig FIGREF27 (b) we present the confusion matrix for the 2D-ConvNet model. 2D attention models focused on the important features extracted by convolutional layers and bi-directional GRU captured the temporal features."
|
| 105 |
+
],
|
| 106 |
+
[
|
| 107 |
+
"Several of the spoken languages in Europe belong to the Indo-European family. Within this family, the languages are divided into three phyla which are Romance, Germanic and Slavic. Of the 6 languages that we selected Spanish (Es), French (Fr) and Italian (It) belong to the Romance phyla, English and German belong to Germanic phyla and Russian in Slavic phyla. Our model also confuses between languages belonging to the similar phyla which acts as an insanity check since languages in same phyla have many similar pronounced words such as cat in English becomes Katze in German and Ciao in Italian becomes Chao in Spanish.",
|
| 108 |
+
"Our model confuses between French (Fr) and Russian (Ru) while these languages belong to different phyla, many words from French were adopted into Russian such as automate (oot-oo-mate) in French becomes ABTOMaT (aff-taa-maat) in Russian which have similar pronunciation.",
|
| 109 |
+
""
|
| 110 |
+
],
|
| 111 |
+
[
|
| 112 |
+
"The performance of raw audio waveforms as input features to ConvNet can be further improved by applying silence removal in the audio. Also, there is scope for improvement by augmenting available data through various conventional techniques like pitch shifting, adding random noise and changing speed of audio. These help in making neural networks more robust to variations which might be present in real world scenarios. There can be further exploration of various feature extraction techniques like Constant-Q transform and Fast Fourier Transform and assessment of their impact on Language Identification.",
|
| 113 |
+
"There can be further improvements in neural network architectures like concatenating the high level features obtained from 1D-ConvNet and 2D-ConvNet, before performing classification. There can be experiments using deeper networks with skip connections and Inception modules. These are known to have positively impacted the performance of Convolutional Neural Networks."
|
| 114 |
+
],
|
| 115 |
+
[
|
| 116 |
+
"There are two main contributions of this paper in the domain of spoken language identification. Firstly, we presented an extensive analysis of raw audio waveforms as input features to 1D-ConvNet. We experimented with various hyperparameters in our 1D-ConvNet and evaluated their effect on validation accuracy. This method is able to bypass the computational overhead of conventional approaches which depend on generation of spectrograms as a necessary pre-procesing step. We were able to achieve an accauracy of 93.7% using this technique.",
|
| 117 |
+
"Next, we discussed the enhancement in performance of 2D-ConvNet using mixup augmentation, which is a recently developed technique to prevent over\ufb01tting on test data.This approach achieved an accuracy of 95.4%. We also analysed how attention mechanism and recurrent layers impact the performance of networks. This approach achieved an accuracy of 95.0%."
|
| 118 |
+
]
|
| 119 |
+
]
|
| 120 |
+
}
|
| 121 |
+
```
|
qasper-0092/instruction.md
ADDED
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| 1 |
+
Name of Paper: Gunrock: A Social Bot for Complex and Engaging Long Conversations
|
| 2 |
+
|
| 3 |
+
Question: How do they correlate user backstory queries to user satisfaction?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"System Architecture",
|
| 12 |
+
"System Architecture ::: Automatic Speech Recognition",
|
| 13 |
+
"System Architecture ::: Natural Language Understanding",
|
| 14 |
+
"System Architecture ::: Dialog Manager",
|
| 15 |
+
"System Architecture ::: Knowledge Databases",
|
| 16 |
+
"System Architecture ::: Natural Language Generation",
|
| 17 |
+
"System Architecture ::: Text To Speech",
|
| 18 |
+
"Analysis",
|
| 19 |
+
"Analysis ::: Response Depth: Mean Word Count",
|
| 20 |
+
"Analysis ::: Gunrock's Backstory and Persona",
|
| 21 |
+
"Analysis ::: Interleaving Personal and Factual Information: Animal Module",
|
| 22 |
+
"Conclusion",
|
| 23 |
+
"Acknowledgments"
|
| 24 |
+
],
|
| 25 |
+
"paragraphs": [
|
| 26 |
+
[
|
| 27 |
+
"Amazon Alexa Prize BIBREF0 provides a platform to collect real human-machine conversation data and evaluate performance on speech-based social conversational systems. Our system, Gunrock BIBREF1 addresses several limitations of prior chatbots BIBREF2, BIBREF3, BIBREF4 including inconsistency and difficulty in complex sentence understanding (e.g., long utterances) and provides several contributions: First, Gunrock's multi-step language understanding modules enable the system to provide more useful information to the dialog manager, including a novel dialog act scheme. Additionally, the natural language understanding (NLU) module can handle more complex sentences, including those with coreference. Second, Gunrock interleaves actions to elicit users' opinions and provide responses to create an in-depth, engaging conversation; while a related strategy to interleave task- and non-task functions in chatbots has been proposed BIBREF5, no chatbots to our knowledge have employed a fact/opinion interleaving strategy. Finally, we use an extensive persona database to provide coherent profile information, a critical challenge in building social chatbots BIBREF3. Compared to previous systems BIBREF4, Gunrock generates more balanced conversations between human and machine by encouraging and understanding more human inputs (see Table TABREF2 for an example)."
|
| 28 |
+
],
|
| 29 |
+
[
|
| 30 |
+
"Figure FIGREF3 provides an overview of Gunrock's architecture. We extend the Amazon Conversational Bot Toolkit (CoBot) BIBREF6 which is a flexible event-driven framework. CoBot provides ASR results and natural language processing pipelines through the Alexa Skills Kit (ASK) BIBREF7. Gunrock corrects ASR according to the context (asr) and creates a natural language understanding (NLU) (nlu) module where multiple components analyze the user utterances. A dialog manager (DM) (dm) uses features from NLU to select topic dialog modules and defines an individual dialog flow. Each dialog module leverages several knowledge bases (knowledge). Then a natural language generation (NLG) (nlg) module generates a corresponding response. Finally, we markup the synthesized responses and return to the users through text to speech (TTS) (tts). While we provide an overview of the system in the following sections, for detailed system implementation details, please see the technical report BIBREF1."
|
| 31 |
+
],
|
| 32 |
+
[
|
| 33 |
+
"Gunrock receives ASR results with the raw text and timestep information for each word in the sequence (without case information and punctuation). Keywords, especially named entities such as movie names, are prone to generate ASR errors without contextual information, but are essential for NLU and NLG. Therefore, Gunrock uses domain knowledge to correct these errors by comparing noun phrases to a knowledge base (e.g. a list of the most popular movies names) based on their phonetic information. We extract the primary and secondary code using The Double Metaphone Search Algorithm BIBREF8 for noun phrases (extracted by noun trunks) and the selected knowledge base, and suggest a potential fix by code matching. An example can be seen in User_3 and Gunrock_3 in Table TABREF2."
|
| 34 |
+
],
|
| 35 |
+
[
|
| 36 |
+
"Gunrock is designed to engage users in deeper conversation; accordingly, a user utterance can consist of multiple units with complete semantic meanings. We first split the corrected raw ASR text into sentences by inserting break tokens. An example is shown in User_3 in Table TABREF2. Meanwhile, we mask named entities before segmentation so that a named entity will not be segmented into multiple parts and an utterance with a complete meaning is maintained (e.g.,\u201ci like the movie a star is born\"). We also leverage timestep information to filter out false positive corrections. After segmentation, our coreference implementation leverages entity knowledge (such as person versus event) and replaces nouns with their actual reference by entity ranking. We implement coreference resolution on entities both within segments in a single turn as well as across multiple turns. For instance, \u201chim\" in the last segment in User_5 is replaced with \u201cbradley cooper\" in Table TABREF2. Next, we use a constituency parser to generate noun phrases from each modified segment. Within the sequence pipeline to generate complete segments, Gunrock detects (1) topic, (2) named entities, and (3) sentiment using ASK in parallel. The NLU module uses knowledge graphs including Google Knowledge Graph to call for a detailed description of each noun phrase for understanding.",
|
| 37 |
+
"In order to extract the intent for each segment, we designed MIDAS, a human-machine dialog act scheme with 23 tags and implemented a multi-label dialog act classification model using contextual information BIBREF9. Next, the NLU components analyzed on each segment in a user utterance are sent to the DM and NLG module for state tracking and generation, respectively."
|
| 38 |
+
],
|
| 39 |
+
[
|
| 40 |
+
"We implemented a hierarchical dialog manager, consisting of a high level and low level DMs. The former leverages NLU outputs for each segment and selects the most important segment for the system as the central element using heuristics. For example, \u201ci just finished reading harry potter,\" triggers Sub-DM: Books. Utilizing the central element and features extracted from NLU, input utterances are mapped onto 11 possible topic dialog modules (e.g., movies, books, animals, etc.), including a backup module, retrieval.",
|
| 41 |
+
"Low level dialog management is handled by the separate topic dialog modules, which use modular finite state transducers to execute various dialog segments processed by the NLU. Using topic-specific modules enables deeper conversations that maintain the context. We design dialog flows in each of the finite state machines, as well. Dialog flow is determined by rule-based transitions between a specified fixed set of dialog states. To ensure that our states and transitions are effective, we leverage large scale user data to find high probability responses and high priority responses to handle in different contexts. Meanwhile, dialog flow is customized to each user by tracking user attributes as dialog context. In addition, each dialog flow is adaptive to user responses to show acknowledgement and understanding (e.g., talking about pet ownership in the animal module). Based on the user responses, many dialog flow variations exist to provide a fresh experience each time. This reduces the feeling of dialogs being scripted and repetitive. Our dialog flows additionally interleave facts, opinions, experiences, and questions to make the conversation flexible and interesting.",
|
| 42 |
+
"In the meantime, we consider feedback signals such as \u201ccontinue\" and \u201cstop\" from the current topic dialog module, indicating whether it is able to respond to the following request in the dialog flow, in order to select the best response module. Additionally, in all modules we allow mixed-initiative interactions; users can trigger a new dialog module when they want to switch topics while in any state. For example, users can start a new conversation about movies from any other topic module."
|
| 43 |
+
],
|
| 44 |
+
[
|
| 45 |
+
"All topic dialog modules query knowledge bases to provide information to the user. To respond to general factual questions, Gunrock queries the EVI factual database , as well as other up-to-date scraped information appropriate for the submodule, such as news and current showing movies in a specific location from databases including IMDB. One contribution of Gunrock is the extensive Gunrock Persona Backstory database, consisting of over 1,000 responses to possible questions for Gunrock as well as reasoning for her responses for roughly 250 questions (see Table 2). We designed the system responses to elicit a consistent personality within and across modules, modeled as a female individual who is positive, outgoing, and is interested in science and technology."
|
| 46 |
+
],
|
| 47 |
+
[
|
| 48 |
+
"In order to avoid repetitive and non-specific responses commonly seen in dialog systems BIBREF10, Gunrock uses a template manager to select from a handcrafted response templates based on the dialog state. One dialog state can map to multiple response templates with similar semantic or functional content but differing surface forms. Among these response templates for the same dialog state, one is randomly selected without repetition to provide variety unless all have been exhausted. When a response template is selected, any slots are substituted with actual contents, including queried information for news and specific data for weather. For example, to ground a movie name due to ASR errors or multiple versions, one template is \u201cAre you talking about {movie_title} released in {release_year} starring {actor_name} as {actor_role}?\". Module-specific templates were generated for each topic (e.g., animals), but some of the templates are generalizable across different modules (e.g., \u201cWhat\u2019s your favorite [movie $|$ book $|$ place to visit]?\")",
|
| 49 |
+
"In many cases, response templates corresponding to different dialog acts are dynamically composed to give the final response. For example, an appropriate acknowledgement for the user\u2019s response can be combined with a predetermined follow-up question."
|
| 50 |
+
],
|
| 51 |
+
[
|
| 52 |
+
"After NLG, we adjust the TTS of the system to improve the expressiveness of the voice to convey that the system is an engaged and active participant in the conversation. We use a rule-based system to systematically add interjections, specifically Alexa Speechcons, and fillers to approximate human-like cognitive-emotional expression BIBREF11. For more on the framework and analysis of the TTS modifications, see BIBREF12."
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"From January 5, 2019 to March 5, 2019, we collected conversational data for Gunrock. During this time, no other code updates occurred. We analyzed conversations for Gunrock with at least 3 user turns to avoid conversations triggered by accident. Overall, this resulted in a total of 34,432 user conversations. Together, these users gave Gunrock an average rating of 3.65 (median: 4.0), which was elicited at the end of the conversation (\u201cOn a scale from 1 to 5 stars, how do you feel about talking to this socialbot again?\"). Users engaged with Gunrock for an average of 20.92 overall turns (median 13.0), with an average of 6.98 words per utterance, and had an average conversation time of 7.33 minutes (median: 2.87 min.). We conducted three principal analyses: users' response depth (wordcount), backstory queries (backstorypersona), and interleaving of personal and factual responses (pets)."
|
| 56 |
+
],
|
| 57 |
+
[
|
| 58 |
+
"Two unique features of Gunrock are its ability to dissect longer, complex sentences, and its methods to encourage users to be active conversationalists, elaborating on their responses. In prior work, even if users are able to drive the conversation, often bots use simple yes/no questions to control the conversational flow to improve understanding; as a result, users are more passive interlocutors in the conversation. We aimed to improve user engagement by designing the conversation to have more open-ended opinion/personal questions, and show that the system can understand the users' complex utterances (See nlu for details on NLU). Accordingly, we ask if users' speech behavior will reflect Gunrock's technical capability and conversational strategy, producing longer sentences.",
|
| 59 |
+
"We assessed the degree of conversational depth by measuring users' mean word count. Prior work has found that an increase in word count has been linked to improved user engagement (e.g., in a social dialog system BIBREF13). For each user conversation, we extracted the overall rating, the number of turns of the interaction, and the user's per-utterance word count (averaged across all utterances). We modeled the relationship between word count and the two metrics of user engagement (overall rating, mean number of turns) in separate linear regressions.",
|
| 60 |
+
"Results showed that users who, on average, produced utterances with more words gave significantly higher ratings ($\\beta $=0.01, SE=0.002, t=4.79, p$<$0.001)(see Figure 2) and engaged with Gunrock for significantly greater number of turns ($\\beta $=1.85, SE=0.05, t=35.58, p$<$0.001) (see Figure 2). These results can be interpreted as evidence for Gunrock's ability to handle complex sentences, where users are not constrained to simple responses to be understood and feel engaged in the conversation \u2013 and evidence that individuals are more satisfied with the conversation when they take a more active role, rather than the system dominating the dialog. On the other hand, another interpretation is that users who are more talkative may enjoy talking to the bot in general, and thus give higher ratings in tandem with higher average word counts."
|
| 61 |
+
],
|
| 62 |
+
[
|
| 63 |
+
"We assessed the user's interest in Gunrock by tagging instances where the user triggered Gunrock's backstory (e.g., \u201cWhat's your favorite color?\"). For users with at least one backstory question, we modeled overall (log) Rating with a linear regression by the (log) `Number of Backstory Questions Asked' (log transformed due to the variables' nonlinear relationship). We hypothesized that users who show greater curiosity about Gunrock will display higher overall ratings for the conversation based on her responses. Overall, the number of times users queried Gunrock's backstory was strongly related to the rating they gave at the end of the interaction (log:$\\beta $=0.10, SE=0.002, t=58.4, p$<$0.001)(see Figure 3). This suggests that maintaining a consistent personality \u2014 and having enough responses to questions the users are interested in \u2014 may improve user satisfaction."
|
| 64 |
+
],
|
| 65 |
+
[
|
| 66 |
+
"Gunrock includes a specific topic module on animals, which includes a factual component where the system provides animal facts, as well as a more personalized component about pets. Our system is designed to engage users about animals in a more casual conversational style BIBREF14, eliciting follow-up questions if the user indicates they have a pet; if we are able to extract the pet's name, we refer to it in the conversation (e.g., \u201cOliver is a great name for a cat!\", \u201cHow long have you had Oliver?\"). In cases where the user does not indicate that they have a pet, the system solely provides animal facts. Therefore, the animal module can serve as a test of our interleaving strategy: we hypothesized that combining facts and personal questions \u2014 in this case about the user's pet \u2014 would lead to greater user satisfaction overall.",
|
| 67 |
+
"We extracted conversations where Gunrock asked the user if they had ever had a pet and categorized responses as \u201cYes\", \u201cNo\", or \u201cNA\" (if users did not respond with an affirmative or negative response). We modeled user rating with a linear regression model, with predictor of \u201cHas Pet' (2 levels: Yes, No). We found that users who talked to Gunrock about their pet showed significantly higher overall ratings of the conversation ($\\beta $=0.15, SE=0.06, t=2.53, p$=$0.016) (see Figure 4). One interpretation is that interleaving factual information with more in-depth questions about their pet result in improved user experience. Yet, another interpretation is that pet owners may be more friendly and amenable to a socialbot; for example, prior research has linked differences in personality to pet ownership BIBREF15."
|
| 68 |
+
],
|
| 69 |
+
[
|
| 70 |
+
"Gunrock is a social chatbot that focuses on having long and engaging speech-based conversations with thousands of real users. Accordingly, our architecture employs specific modules to handle longer and complex utterances and encourages users to be more active in a conversation. Analysis shows that users' speech behavior reflects these capabilities. Longer sentences and more questions about Gunrocks's backstory positively correlate with user experience. Additionally, we find evidence for interleaved dialog flow, where combining factual information with personal opinions and stories improve user satisfaction. Overall, this work has practical applications, in applying these design principles to other social chatbots, as well as theoretical implications, in terms of the nature of human-computer interaction (cf. 'Computers are Social Actors' BIBREF16). Our results suggest that users are engaging with Gunrock in similar ways to other humans: in chitchat about general topics (e.g., animals, movies, etc.), taking interest in Gunrock's backstory and persona, and even producing more information about themselves in return."
|
| 71 |
+
],
|
| 72 |
+
[
|
| 73 |
+
"We would like to acknowledge the help from Amazon in terms of financial and technical support."
|
| 74 |
+
]
|
| 75 |
+
]
|
| 76 |
+
}
|
| 77 |
+
```
|
qasper-0093/instruction.md
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|
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|
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|
| 1 |
+
Name of Paper: Towards Detection of Subjective Bias using Contextualized Word Embeddings
|
| 2 |
+
|
| 3 |
+
Question: Do the authors report only on English?
|
qasper-0094/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: Towards Detection of Subjective Bias using Contextualized Word Embeddings
|
| 2 |
+
|
| 3 |
+
Question: What is the baseline for the experiments?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Baselines and Approach",
|
| 12 |
+
"Baselines and Approach ::: Baselines",
|
| 13 |
+
"Baselines and Approach ::: Proposed Approaches",
|
| 14 |
+
"Experiments ::: Dataset and Experimental Settings",
|
| 15 |
+
"Experiments ::: Experimental Results",
|
| 16 |
+
"Conclusion"
|
| 17 |
+
],
|
| 18 |
+
"paragraphs": [
|
| 19 |
+
[
|
| 20 |
+
"In natural language, subjectivity refers to the aspects of communication used to express opinions, evaluations, and speculationsBIBREF0, often influenced by one's emotional state and viewpoints. Writers and editors of texts like news and textbooks try to avoid the use of biased language, yet subjective bias is pervasive in these texts. More than $56\\%$ of Americans believe that news sources do not report the news objectively , thus implying the prevalence of the bias. Therefore, when presenting factual information, it becomes necessary to differentiate subjective language from objective language.",
|
| 21 |
+
"There has been considerable work on capturing subjectivity using text-classification models ranging from linguistic-feature-based modelsBIBREF1 to finetuned pre-trained word embeddings like BERTBIBREF2. The detection of bias-inducing words in a Wikipedia statement was explored in BIBREF1. The authors propose the \"Neutral Point of View\" (NPOV) corpus made using Wikipedia revision history, containing Wikipedia edits that are specifically designed to remove subjective bias. They use logistic regression with linguistic features, including factive verbs, hedges, and subjective intensifiers to detect bias-inducing words. In BIBREF2, the authors extend this work by mitigating subjective bias after detecting bias-inducing words using a BERT-based model. However, they primarily focused on detecting and mitigating subjective bias for single-word edits. We extend their work by incorporating multi-word edits by detecting bias at the sentence level. We further use their version of the NPOV corpus called Wiki Neutrality Corpus(WNC) for this work.",
|
| 22 |
+
"The task of detecting sentences containing subjective bias rather than individual words inducing the bias has been explored in BIBREF3. However, they conduct majority of their experiments in controlled settings, limiting the type of articles from which the revisions were extracted. Their attempt to test their models in a general setting is dwarfed by the fact that they used revisions from a single Wikipedia article resulting in just 100 instances to evaluate their proposed models robustly. Consequently, we perform our experiments in the complete WNC corpus, which consists of $423,823$ revisions in Wikipedia marked by its editors over a period of 15 years, to simulate a more general setting for the bias.",
|
| 23 |
+
"In this work, we investigate the application of BERT-based models for the task of subjective language detection. We explore various BERT-based models, including BERT, RoBERTa, ALBERT, with their base and large specifications along with their native classifiers. We propose an ensemble model exploiting predictions from these models using multiple ensembling techniques. We show that our model outperforms the baselines by a margin of $5.6$ of F1 score and $5.95\\%$ of Accuracy."
|
| 24 |
+
],
|
| 25 |
+
[
|
| 26 |
+
"In this section, we outline baseline models like $BERT_{large}$. We further propose three approaches: optimized BERT-based models, distilled pretrained models, and the use of ensemble methods for the task of subjectivity detection."
|
| 27 |
+
],
|
| 28 |
+
[
|
| 29 |
+
"FastTextBIBREF4: It uses bag of words and bag of n-grams as features for text classification, capturing partial information about the local word order efficiently.",
|
| 30 |
+
"BiLSTM: Unlike feedforward neural networks, recurrent neural networks like BiLSTMs use memory based on history information to learn long-distance features and then predict the output. We use a two-layer BiLSTM architecture with GloVe word embeddings as a strong RNN baseline.",
|
| 31 |
+
"BERT BIBREF5: It is a contextualized word representation model that uses bidirectional transformers, pretrained on a large $3.3B$ word corpus. We use the $BERT_{large}$ model finetuned on the training dataset."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"Optimized BERT-based models: We use BERT-based models optimized as in BIBREF6 and BIBREF7, pretrained on a dataset as large as twelve times as compared to $BERT_{large}$, with bigger batches, and longer sequences. ALBERT, introduced in BIBREF7, uses factorized embedding parameterization and cross-layer parameter sharing for parameter reduction. These optimizations have led both the models to outperform $BERT_{large}$ in various benchmarking tests, like GLUE for text classification and SQuAD for Question Answering.",
|
| 35 |
+
"Distilled BERT-based models: Secondly, we propose to use distilled BERT-based models, as introduced in BIBREF8. They are smaller general-purpose language representation model, pre-trained by leveraging distillation knowledge. This results in significantly smaller and faster models with performance comparable to their undistilled versions. We finetune these pretrained distilled models on the training corpus to efficiently detect subjectivity.",
|
| 36 |
+
"BERT-based ensemble models: Lastly, we use the weighted-average ensembling technique to exploit the predictions made by different variations of the above models. Ensembling methodology entails engendering a predictive model by utilizing predictions from multiple models in order to improve Accuracy and F1, decrease variance, and bias. We experiment with variations of $RoBERTa_{large}$, $ALBERT_{xxlarge.v2}$, $DistilRoBERTa$ and $BERT$ and outline selected combinations in tab:experimental-results."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"We perform our experiments on the WNC dataset open-sourced by the authors of BIBREF2. It consists of aligned pre and post neutralized sentences made by Wikipedia editors under the neutral point of view. It contains $180k$ biased sentences, and their neutral counterparts crawled from $423,823$ Wikipedia revisions between 2004 and 2019. We randomly shuffled these sentences and split this dataset into two parts in a $90:10$ Train-Test split and perform the evaluation on the held-out test dataset.",
|
| 40 |
+
"For all BERT-based models, we use a learning rate of $2*10^{-5}$, a maximum sequence length of 50, and a weight decay of $0.01$ while finetuning the model. We use FastText's recently open-sourced automatic hyperparameter optimization functionality while training the model. For the BiLSTM baseline, we use a dropout of $0.05$ along with a recurrent dropout of $0.2$ in two 64 unit sized stacked BiLSTMs, using softmax activation layer as the final dense layer."
|
| 41 |
+
],
|
| 42 |
+
[
|
| 43 |
+
"tab:experimental-results shows the performance of different models on the WNC corpus evaluated on the following four metrics: Precision, Recall, F1, and Accuracy. Our proposed methodology, the use of finetuned optimized BERT based models, and BERT-based ensemble models outperform the baselines for all the metrics.",
|
| 44 |
+
"Among the optimized BERT based models, $RoBERTa_{large}$ outperforms all other non-ensemble models and the baselines for all metrics. It further achieves a maximum recall of $0.681$ for all the proposed models. We note that DistillRoBERTa, a distilled model, performs competitively, achieving $69.69\\%$ accuracy, and $0.672$ F1 score. This observation shows that distilled pretrained models can replace their undistilled counterparts in a low-computing environment.",
|
| 45 |
+
"We further observe that ensemble models perform better than optimized BERT-based models and distilled pretrained models. Our proposed ensemble comprising of $RoBERTa_{large}$, $ALBERT_{xxlarge.v2}$, $DistilRoBERTa$ and $BERT$ outperforms all the proposed models obtaining $0.704$ F1 score, $0.733$ precision, and $71.61\\%$ Accuracy."
|
| 46 |
+
],
|
| 47 |
+
[
|
| 48 |
+
"In this paper, we investigated BERT-based architectures for sentence level subjective bias detection. We perform our experiments on a general Wikipedia corpus consisting of more than $360k$ pre and post subjective bias neutralized sentences. We found our proposed architectures to outperform the existing baselines significantly. BERT-based ensemble consisting of RoBERTa, ALBERT, DistillRoBERTa, and BERT led to the highest F1 and Accuracy. In the future, we would like to explore document-level detection of subjective bias, multi-word mitigation of the bias, applications of detecting the bias in recommendation systems."
|
| 49 |
+
]
|
| 50 |
+
]
|
| 51 |
+
}
|
| 52 |
+
```
|
qasper-0095/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
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|
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|
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|
|
| 1 |
+
Name of Paper: Towards Detection of Subjective Bias using Contextualized Word Embeddings
|
| 2 |
+
|
| 3 |
+
Question: Which experiments are perfomed?
|
qasper-0104/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
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| 1 |
+
Name of Paper: Unsupervised Machine Commenting with Neural Variational Topic Model
|
| 2 |
+
|
| 3 |
+
Question: Which lexicon-based models did they compare with?
|
qasper-0112/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
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| 1 |
+
Name of Paper: Diachronic Topics in New High German Poetry
|
| 2 |
+
|
| 3 |
+
Question: Is the outcome of the LDA analysis evaluated in any way?
|
qasper-0113/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: Diachronic Topics in New High German Poetry
|
| 2 |
+
|
| 3 |
+
Question: What is the corpus used in the study?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Corpus",
|
| 11 |
+
"Experiments",
|
| 12 |
+
"Experiments ::: Topic Trends",
|
| 13 |
+
"Experiments ::: Classification of Time Periods and Authorship",
|
| 14 |
+
"Experiments ::: Conclusion & Future Work"
|
| 15 |
+
],
|
| 16 |
+
"paragraphs": [
|
| 17 |
+
[
|
| 18 |
+
"The Digital Library in the TextGrid Repository represents an extensive collection of German texts in digital form BIBREF3. It was mined from http://zeno.org and covers a time period from the mid 16th century up to the first decades of the 20th century. It contains many important texts that can be considered as part of the literary canon, even though it is far from complete (e.g. it contains only half of Rilke\u2019s work). We find that around 51k texts are annotated with the label \u2019verse\u2019 (TGRID-V), not distinguishing between \u2019lyric verse\u2019 and \u2019epic verse\u2019. However, the average length of these texts is around 150 token, dismissing most epic verse tales. Also, the poems are distributed over 229 authors, where the average author contributed 240 poems (median 131 poems). A drawback of TGRID-V is the circumstance that it contains a noticeable amount of French, Dutch and Latin (over 400 texts). To constrain our dataset to German, we filter foreign language material with a stopword list, as training a dedicated language identification classifier is far beyond the scope of this work."
|
| 19 |
+
],
|
| 20 |
+
[
|
| 21 |
+
"We approach diachronic variation of poetry from two perspectives. First, as distant reading task to visualize the development of clearly interpretable topics over time. Second, as a downstream task, i.e. supervised machine learning task to determine the year (the time-slot) of publication for a given poem. We infer topic distributions over documents as features and pit them against a simple style baseline.",
|
| 22 |
+
"We use the implementation of LDA as it is provided in genism BIBREF4. LDA assumes that a particular document contains a mixture of few salient topics, where words are semantically related. We transform our documents (of wordforms) to a bag of words representation, filter stopwords (function words), and set the desired number of topics=100 and train for 50 epochs to attain a reasonable distinctness of topics. We choose 100 topics (rather than a lower number that might be more straightforward to interpret) as we want to later use these topics as features for downstream tasks. We find that wordforms (instead of lemma) are more useful for poetry topic models, as these capture style features (rhyme), orthographic variations ('hertz' instead of 'herz'), and generally offer more interpretable results."
|
| 23 |
+
],
|
| 24 |
+
[
|
| 25 |
+
"We retrieve the most important (likely) words for all 100 topics and interpret these (sorted) word lists as aggregated topics, e.g. topic 27 (figure 2) contains: Tugend (virtue), Kunst (art), Ruhm (fame), Geist (spirit), Verstand (mind) and Lob (praise). This topic as a whole describes the concept of \u2019artistic virtue\u2019.",
|
| 26 |
+
"In certain clusters (topics) we find poetic residuals, such that rhyme words often cluster together (as they stand in proximity), e.g. topic 52 with: Mund (mouth), Grund (cause, ground), rund (round).",
|
| 27 |
+
"To discover trends of topics over time, we bin our documents into time slots of 25 years width each. See figure 1 for a plot of the number of documents per bin. The chosen binning slots offer enough documents per slot for our experiments. To visualize trends of singular topics over time, we aggregate all documents d in slot s and add the probabilities of topic t given d and divide by the number of all d in s. This gives us the average probability of a topic per timeslot. We then plot the trajectories for each single topic. See figures 2\u20136 for a selection of interpretable topic trends. Please note that the scaling on the y-axis differ for each topic, as some topics are more pronounced in the whole dataset overall.",
|
| 28 |
+
"Some topic plots are already very revealing. The topic \u2018artistic virtue\u2019 (figure 2, left) shows a sharp peak around 1700\u20141750, outlining the period of Enlightenment. Several topics indicate Romanticism, such as \u2018flowers\u2019 (figure 2, right), \u2018song\u2019 (figure 3, left) or \u2018dust, ghosts, depths\u2019 (not shown). The period of 'Vorm\u00e4rz' or 'Young Germany' is quite clear with the topic \u2018German Nation\u2019 (figure 3, right). It is however hardly distinguishable from romantic topics.",
|
| 29 |
+
"We find that the topics 'Beautiful Girls' (figure 4, left) and 'Life & Death' (figure 4, right) are always quite present over time, while 'Girls' is more prounounced in Romanticism, and 'Death' in Barock.",
|
| 30 |
+
"We find that the topic 'Fire' (figure 5, left) is a fairly modern concept, that steadily rises into modernity, possibly because of the trope 'love is fire'. Next to it, the topic 'Family' (figure 5, right) shows wild fluctuation over time.",
|
| 31 |
+
"Finally, figure 6 shows topics that are most informative for the downstream classification task: Topic 11 'World, Power, Time' (left) is very clearly a Barock topic, ending at 1750, while topic 19 'Heaven, Depth, Silence' is a topic that rises from Romanticism into Modernity."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"To test whether topic models can be used for dating poetry or attributing authorship, we perform supervised classification experiments with Random Forest Ensemble classifiers. We find that we obtain better results by training and testing on stanzas instead of full poems, as we have more data available. Also, we use 50 year slots (instead of 25) to ease the task.",
|
| 35 |
+
"For each document we determine a class label for a time slot. The slot 1575\u20131624 receives the label 0, the slot 1625\u20131674 the label 1, etc.. In total, we have 7 classes (time slots).",
|
| 36 |
+
"As a baseline, we implement rather straightforward style features, such as line length, poem length (in token, syllables, lines), cadence (number of syllables of last word in line), soundscape (ratio of closed to open syllables, see BIBREF5), and a proxy for metre, the number of syllables of the first word in the line.",
|
| 37 |
+
"We split the data randomly 70:30 training:testing, where a 50:50 shows (5 points) worse performance. We then train Random Forest Ensemble classifiers and perform a grid search over their parameters to determine the best classifier. Please note that our class sizes are quite imbalanced.",
|
| 38 |
+
"The Style baseline achieves an Accuracy of 83%, LDA features 89% and a combination of the two gets 90%. However, training on full poems reduces this to 42\u201452%.",
|
| 39 |
+
"The most informative features (by information gain) are: Topic11 (.067), Topic 37 (.055), Syllables Per Line (.046), Length of poem in syllables (.031), Topic19 (.029), Topic98 (.025), Topic27 ('virtue') (.023), and Soundscape (.023).",
|
| 40 |
+
"For authorship attribution, we also use a 70:30 random train:test split and use the author name as class label. We only choose the most frequent 180 authors. We find that training on stanzas gives us 71% Accuracy, but when trained on full poems, we only get 13% Accuracy. It should be further investigated is this is only because of a surplus of data."
|
| 41 |
+
],
|
| 42 |
+
[
|
| 43 |
+
"We have shown the viability of Latent Dirichlet Allocation for a visualization of topic trends (the evolution of what people talk about in poetry). While most topics are easily interpretable and show a clear trend, others are quite noisy. For an exploratory experiment, the classification into time slots and for authors attribution is very promising, however far from perfect. It should be investigated whether using stanzas instead of whole poems only improves results because of more available data. Also, it needs to be determined if better topic models can deliver a better baseline for diachronic change in poetry, and if better style features will outperform semantics. Finally, only selecting clear trending and peaking topics (through co-variance) might further improve the results."
|
| 44 |
+
]
|
| 45 |
+
]
|
| 46 |
+
}
|
| 47 |
+
```
|
qasper-0114/instruction.md
ADDED
|
@@ -0,0 +1,98 @@
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|
| 1 |
+
Name of Paper: Important Attribute Identification in Knowledge Graph
|
| 2 |
+
|
| 3 |
+
Question: What are the traditional methods to identifying important attributes?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"The problem we solve in this paper",
|
| 11 |
+
"Related Research",
|
| 12 |
+
"What we propose and what we have done",
|
| 13 |
+
"Our proposed Method",
|
| 14 |
+
"Application Scenario",
|
| 15 |
+
"FastText Introduction",
|
| 16 |
+
"Matching",
|
| 17 |
+
"Data introduction",
|
| 18 |
+
"Data preprocessing",
|
| 19 |
+
"Proposed method vs previous methods",
|
| 20 |
+
"Result Analysis",
|
| 21 |
+
"Conclusions and Future work "
|
| 22 |
+
],
|
| 23 |
+
"paragraphs": [
|
| 24 |
+
[
|
| 25 |
+
"Knowledge graph(KG) has been proposed for several years and its most prominent application is in web search, for example, Google search triggers a certain entity card when a user's query matches or mentions an entity based on some statistical model. The core potential of a knowledge graph is about its capability of reasoning and inferring, and we have not seen revolutionary breakthrough in such areas yet. One main obstacle is obviously the lack of sufficient knowledge graph data, including entities, entities' descriptions, entities' attributes, and relationship between entities. A full functional knowledge graph supporting general purposed reasoning and inference might still require long years of the community's innovation and hardworking. On the other hand, many less demanding applications have great potential benefiting from the availability of information from the knowledge graph, such as query understanding and document understanding in information retrieval/search engines, simple inference in question answering systems, and easy reasoning in domain-limited decision support tools. Not only academy, but also industry companies have been heavily investing in knowledge graphs, such as Google's knowledge graph, Amazon's product graph, Facebook's Graph API, IBM's Watson, and Microsoft's Satori etc.",
|
| 26 |
+
"In the existing knowledge graph, such as Wikidata and DBpedia, usually attributes do not have order or priorities, and we don't know which attributes are more important and of more interest to users. Such importance score of attributes is a vital piece of information in many applications of knowledge graph. The most important application is the triggered entity card in search engine when a customer's query gets hit for an entity. An entity usually has a large amount of attributes, but an entity card has limited space and can only show the most significant information; attribute importance's presence can make the displaying of an entity card easy to implement. Attribute importance also has great potential of playing a significant role in search engine, how to decide the matching score between the query and attribute values. If the query matches a very important attribute, and the relevance contribution from such a match should be higher than matching an ignorable attribute. Another application is in e-commerce communications, and one buyer initiates a communication cycle with a seller by sending a product enquiry. Writing the enquiry on a mobile phone is inconvenient and automatic composing assistance has great potential of improving customer experience by alleviating the writing burden. In the product enquiry, customers need to specify their requirements and ask questions about products, and their requirements and questions are usually about the most important attributes of the products. If we can identify out important attributes of products, we can help customers to draft the enquiry automatically to reduce their input time."
|
| 27 |
+
],
|
| 28 |
+
[
|
| 29 |
+
"Many proposed approaches formulate the entity attribute ranking problem as a post processing step of automated attribute-value extraction. In BIBREF0 , BIBREF1 , BIBREF2 , Pasca et al. firstly extract potential class-attribute pairs using linguistically motivated patterns from unstructured text including query logs and query sessions, and then score the attributes using the Bayes model. In BIBREF3 , Rahul Rai proposed to identify product attributes from customer online reviews using part-of-speech(POS) tagging patterns, and to evaluate their importance with several different frequency metrics. In BIBREF4 , Lee et al. developed a system to extract concept-attribute pairs from multiple data sources, such as Probase, general web documents, query logs and external knowledge base, and aggregate the weights from different sources into one consistent typicality score using a Ranking SVM model. Those approaches typically suffer from the poor quality of the pattern rules, and the ranking process is used to identify relatively more precise attributes from all attribute candidates.",
|
| 30 |
+
"As for an already existing knowledge graph, there is plenty of work in literature dealing with ranking entities by relevance without or with a query. In BIBREF5 , Li et al. introduced the OntoRank algorithm for ranking the importance of semantic web objects at three levels of granularity: document, terms and RDF graphs. The algorithm is based on the rational surfer model, successfully used in the Swoogle semantic web search engine. In BIBREF6 , Hogan et al. presented an approach that adapted the well-known PageRank/HITS algorithms to semantic web data, which took advantage of property values to rank entities. In BIBREF7 , BIBREF8 , authors also focused on ranking entities, sorting the semantic web resources based on importance, relevance and query length, and aggregating the features together with an overall ranking model.",
|
| 31 |
+
"Just a few works were designated to specifically address the problem of computing attribute rankings in a given Knowledge Graph. Ibminer BIBREF9 introduced a tool for infobox(alias of an entity card) template suggestion, which collected attributes from different sources and then sorted them by popularity based on their co-occurrences in the dataset. In BIBREF10 , using the structured knowledge base, intermediate features were computed, including the importance or popularity of each entity type, IDF computation for each attribute on a global basis, IDF computation for entity types etc., and then the features were aggregated to train a classifier. Also, a similar approach in BIBREF11 was designed with more features extracted from GoogleSuggestChars data. In BIBREF12 , Ali et al. introduced a new set of features that utilizes semantic information about entities as well as information from top-ranked documents from a general search engine. In order to experiment their approach, they collected a dataset by exploiting Wikipedia infoboxes, whose ordering of attributes reflect the collaborative effort of a large community of users, which might not be accurate."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"There have been broad researches on entity detection, relationship extraction, and also missing relationship prediction. For example: BIBREF13 , BIBREF14 and BIBREF15 explained how to construct a knowledge graph and how to perform representation learning on knowledge graphs. Some research has been performed on attribute extraction, such as BIBREF16 and BIBREF4 ; the latter one is quite special that it also simultaneously computes the attribute importance. As for modeling attribute importance for an existing knowledge graph which has completed attribute extractions, we found only a few existing research, all of which used simple co-occurrences to rank entity attributes. In reality, many knowledge graphs do not contain attribute importance information, for example, in the most famous Wikidata, a large amount of entities have many attributes, and it is difficult to know which attributes are significant and deserve more attention. In this research we focus on identifying important attributes in existing knowledge graphs. Specifically, we propose a new method of using extra user generated data source for evaluating the attribute importance, and we use the recently proposed state-of-the-art word/sub-word embedding techniques to match the external data with the attribute definition and values from entities in knowledge graphs. And then we use the statistics obtained from the matching to compare the attribute importance. Our method has general extensibility to any knowledge graph without attribute importance. When there is a possibility of finding external textual data source, our proposed method will work, even if the external data does not exactly match the attribute textual data, since the vector embedding performs semantic matching and does not require exact string matching.",
|
| 35 |
+
"The remaining of the paper is organized as follows: Section SECREF2 explains our proposed method in detail, including what kind of external data is required, and how to process the external data, and also how to perform the semantic matching and how to rank the attributes by statistics. Section SECREF3 introduces our experimentations, including our experimentation setup, data introduction and experimental result compared to other methods we do not employ. Section SECREF3 also briefly introduces our real world application scenario in e-commerce communication. Section SECREF4 draws the conclusion from our experimentations and analysis, and also we point out promising future research directions."
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"In this section, we will introduce our proposed method in detail. We use our application scenario to explain the logic behind the method, but the scope is not limited to our use case, and it is possible to extend to any existing knowledge graph without attribute importance information."
|
| 39 |
+
],
|
| 40 |
+
[
|
| 41 |
+
"Alibaba.com is currently the world's largest cross-border business to business(B2B) E-commerce platform and it supports 17 languages for customers from all over the world. On the website, English is the dorminant language and accounts for around 50% of the traffic. The website has already accumulated a very large knowledge graph of products, and the entity here is the product or the product category; and every entity has lots of information such as the entity name, images and many attributes without ordering information. The entities are also connected by taxonomy structure and similar products usually belong to the same category/sub-category.",
|
| 42 |
+
"Since the B2B procurement usually involves a large amount of money, the business will be a long process beginning with a product enquiry. Generally speaking, when customers are interested in some product, they will start a communication cycle with a seller by sending a product enquiry to the seller. In the product enquiry, customers will specify their requirements and ask questions about the product. Their requirements and questions usually refer to the most important attributes of the product. Fig. FIGREF5 shows an enquery example. Alibaba.com has accumulated tens of millions of product enquires, and we would like to leverage these information, in combination of the product knowledge graph we have, to figure out the most important attributes for each category of products.",
|
| 43 |
+
"In our application scenario, the product knowledge graph is the existing knowledge graph and the enquiry data is the external textual data source. From now on, we will use our application scenario to explain the details of our proposed algorithm.",
|
| 44 |
+
"We propose an unsupervised learning framework for extracting important product attributes from product enquiries. By calculating the semantic similarity between each enquiry sentence and each attribute of the product to which the enquiry corresponds to, we identify the product attributes that the customer cares about most.",
|
| 45 |
+
"The attributes described in the enquiry may contain attribute names or attribute values or other expressions, for example, either the word \u201ccolor\u201d or a color instance word \u201cpurple\u201d is mentioned. Therefore, when calculating the semantic similarity between enquiry sentences and product attributes, we need both attribute names and attribute values. The same as any other knowledge graph, the product attributes in our knowledge graph we use contain noises and mistakes. We need to clean and normalize the attribute data before consuming it. We will introduce the detail of our data cleaning process in Section SECREF14 ."
|
| 46 |
+
],
|
| 47 |
+
[
|
| 48 |
+
"FastText is a library created by the Facebook Research for efficient learning of word representations and sentence classification. Here, we just use the word representation functionality of it.",
|
| 49 |
+
"FastText models morphology by considering subword units, and representing words by a sum of its character n-grams BIBREF17 . In the original model the authors choose to use the binary logistic loss and the loss for a single instance is written as below: INLINEFORM0 ",
|
| 50 |
+
"By denoting the logistic loss function INLINEFORM0 , the loss over a sentence is: INLINEFORM1 ",
|
| 51 |
+
"The scoring function between a word INLINEFORM0 and a context word INLINEFORM1 is: INLINEFORM2 ",
|
| 52 |
+
"In the above functions, INLINEFORM0 is a set of negative examples sampled from the vocabulary, INLINEFORM1 is the set of indices of words surrounding word INLINEFORM2 , INLINEFORM3 is the set of n-grams appearing in word INLINEFORM4 , INLINEFORM5 is the size of the dictionary we have for n-grams, INLINEFORM6 is a vector representation to each n-gram INLINEFORM7 .",
|
| 53 |
+
"Compared with word2vec or glove, FastText has following advantages:",
|
| 54 |
+
"It is able to cover rare words and out-of-vocabulary(OOV) words. Since the basic modeling units in FastText are ngrams, and both rare words and OOV ones can obtain efficient word representations from their composing ngrams. Word2vec and glove both fail to provide accurate vector representations for these words. In our application, the training data is written by end customers, and there are many misspellings which easily become OOV words.",
|
| 55 |
+
"Character n-grams embeddings tend to perform superior to word2vec and glove on smaller datasets.",
|
| 56 |
+
"FastText is more efficient and its training is relatively fast."
|
| 57 |
+
],
|
| 58 |
+
[
|
| 59 |
+
"In this section, how to compute the matching between an enquiry sentence and a product attribute is explained in detail. Our explanation here is for a certain product category, and other categories are the same.",
|
| 60 |
+
"As you can see in Fig. FIGREF12 , each sentence is compared with each attribute of a product category that the product belongs to. We now get a score between a sentence INLINEFORM0 and an attribute INLINEFORM1 , INLINEFORM2 INLINEFORM3 ",
|
| 61 |
+
"where INLINEFORM0 is all the possible values for this INLINEFORM1 , INLINEFORM2 is the word vector for INLINEFORM3 . According to this formula, we can get top two attributes whose scores are above the threshold INLINEFORM4 for each sentence. We choose two attributes instead of one because there may be more than one attribute for each sentence. In addition, some sentences are greetings or self-introduction and do not contain the attribute information of the product, so we require that the score to be higher than a certain threshold."
|
| 62 |
+
],
|
| 63 |
+
[
|
| 64 |
+
"For our knowledge graph data, entity(product) attributes can be roughly divided into clusters of transaction order specific ones and product specific ones, in this paper, we choose the product specific ones for further study. We also need to point out that we only focus on the recommended communication language on the Alibaba.com platform, which is English.",
|
| 65 |
+
"To construct the evaluation dataset, top 14 categories are first chosen based on their business promotion features, and 3 millions typical products under each category were then chosen to form the attribute candidates. After preprocessing and basic filtering, top product specific attributes from the 14 different categories are chosen to be manually labeled by our annotators.",
|
| 66 |
+
"For each category, annotators each are asked to choose at most 10 important attributes from buyers perspective. After all annotators complete their annotations, attributes are then sorted according to the summed votes. In the end, 111 important attributes from the 14 categories are kept for final evaluation.",
|
| 67 |
+
"Outside of the evaluation explained in this paper, we actually have performed the matching on more than 4,000 catetories covering more than 100 million products and more than 20 million enquires. Due to limited annotation resources, we can only sample a small numbered categories(14 here) to evaluate the proposed algorithm here."
|
| 68 |
+
],
|
| 69 |
+
[
|
| 70 |
+
"The product enquiries and attributes data preprocessing is shown in Algorithm 1. algorithmAlgorithm Data Preprocess Algorithm [1] INLINEFORM0 INLINEFORM1 : INLINEFORM2 INLINEFORM3 INLINEFORM4 : INLINEFORM5 Invalid INLINEFORM6 filter INLINEFORM7 Split INLINEFORM8 to sentences sentence INLINEFORM9 in INLINEFORM10 INLINEFORM11 INLINEFORM12 return INLINEFORM13 ",
|
| 71 |
+
"Firstly, for every product enquiry, we convert the original html textual data into the plain text. Secondly we filter out the useless enquires, such as non-English enquires and spams. The regular expressions and spam detection are used to detect non-English enquiries and spams respectively. Thirdly we get sentence list INLINEFORM0 with spliting every enquiry into sentences as described in section 2.2. Then for every sentence INLINEFORM1 in INLINEFORM2 , we need to do extra three processes: a)Spelling Correction. b)Regular Measures and Numbers. c)Stop Words Dropping.",
|
| 72 |
+
"Spelling Correction. Since quite a lot of the product enquires and self-filled attributes were misspelled, we have replaced the exact words by fuzzyfied search using Levenshtein distance. The method uses fuzzyfied search, only if the exact match is not found. Some attributes are actually the same, such as \"type\" and \"product type\", we merge these same attributes by judging whether the attributes are contained.",
|
| 73 |
+
"Regular Measures and Numbers. Attributes of number type have their values composed of numbers and units, such as INLINEFORM0 , INLINEFORM1 , INLINEFORM2 , INLINEFORM3 , etc. We replace all numbers (in any notation, e.g., floating point, scientific, arithmetical expression, etc.) with a unique token ( INLINEFORM4 ). For the same reason, each unit of measure is replaced with a corresponding token, eg., INLINEFORM5 is replaced with centimeter area.",
|
| 74 |
+
"Stop Words Dropping. Stop words appear to be of little value in the proposed matching algorithm. By removing the stop words we can focus on the important words instead. In our business scenario, we built a stop words list for foreign trade e-commerce.",
|
| 75 |
+
"Finally, we get the valid sentences INLINEFORM0 ."
|
| 76 |
+
],
|
| 77 |
+
[
|
| 78 |
+
"The existing co-occurrence methods do not suit our application scenario at all, since exact string matching is too strong a requirement and initial trial has shown its incompetency. In stead we implemented an improved version of their method based on TextRank as our baseline. In addition, we also tested multiple semantic matching algorithms for comparison with our chosen method.",
|
| 79 |
+
"TextRank: TextRank is a graph-based ranking model for text processing. BIBREF18 It is an unsupervised algorithm for keyword extraction. Since product attributes are usually the keywords in enquiries, we can compare these keywords with the category attributes and find the most important attributes. This method consists of three steps. The first step is to merge all enquiries under one category as an article. The second step is to extract the top 50 keywords for each category. The third step is to find the most important attributes by comparing top keywords with category attributes.",
|
| 80 |
+
"Word2vec BIBREF19 : We use the word vector trained by BIBREF19 as the distributed representation of words. Then we get the enquiry sentence representation and category attribute representation. Finally we collect the statistics about the matched attributes of each category, and select the most frequent attributes under the same category.",
|
| 81 |
+
"GloVe BIBREF20 : GloVe is a global log-bilinear regression model for the unsupervised learning of word representations, which utilizes the ratios of word-word co-occurrence probabilities. We use the GloVe method to train the distributed representation of words. And attribute selection procedure is the same as word2vec.",
|
| 82 |
+
"Proposed method: the detail of our proposed algorithm has been carefully explained in Section SECREF2 . There are several thresholds we need to pick in the experimentation setup. Based on trial and error analysis, we choose 0.75 as the sentence and attribute similarity threshold, which balances the precision and recall relatively well. In our application, due to product enquiry length limitation, customers usually don't refer to more than five attributes in their initial approach to the seller, we choose to keep 5 most important attributes for each category.",
|
| 83 |
+
"Evaluation is conducted by comparing the output of the systems with the manual annotated answers, and we calculate the precision and recall rate. INLINEFORM0 INLINEFORM1 ",
|
| 84 |
+
"where INLINEFORM0 is the manually labeled attributes , INLINEFORM1 is the detected important attributes.",
|
| 85 |
+
"Table 1 depicts the algorithm performance of each category and the overall average metrics among all categories for our approach and other methods. It can be observed that our proposed method achieves the best performance. The average F1-measure of our approach is 0.47, while the average F1-measure values of \u201cGloVe\u201d, \u201cword2vect\u201d and \"TextRank\" are 0.46, 0.42 and 0.20 respectively."
|
| 86 |
+
],
|
| 87 |
+
[
|
| 88 |
+
"In all our experiments, we find that FastText method outperforms other methods. By analyzing all results, we observe that semantic similarity based methods are more effective than the previous method which we implemented based on TextRank. This conclusion is understandable because lots of enquiries do not simply mention attribute words exactly, but some semantically related words are also used.",
|
| 89 |
+
"Evaluating FastText, GloVe and word2vec, we show that compared to other word representation learning algorithms, the FastText performs best. We sample and analyze the category attributes and find that many self-filled attributes contain misspellings. The FastText algorithm represents words by a sum of its character n-grams and it is much robust against problems like misspellings. In summary, FastText has greater advantages in dealing with natural language corpus usually with spelling mistakes.",
|
| 90 |
+
"We also applied the detected attributes in the automatic enquiry generation task and we obtained significantly better generated enquiries compared to previous rigid templates. Due to space limitation, we skip the explanation and leave it for future publications."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"In this paper, we proposed a new general method of identifying important attributes for entities from a knowledge graph. This is a relatively new task and our proposed method of using external textual data and performing semantic matching via word/sub-word embeddings obtained better result compared to other work of using naive string matching and counting. In addition, we also successfully applied the detected important attributes in our real world application of smart composing. In summary, the method is extensible to any knowledge graph without attribute importance information and outperforms previous method.",
|
| 94 |
+
"In future work, there are two major areas with potential of improving the detection accuracy. The first one is about sentence splitting. What we are trying to get is semantic cohesive unit, which can be used to match an attribute, and there might be more comprehensive method than the simple splitting by sentence ending punctuations. The second one is about improving the word embedding quality. We have implemented an in-house improved version of Fasttext, which is adapted to our data source. It is highly possible to use the improved word embedding on purpose of obtaining higher semantic matching precision. As for the application, we will try to use more statistical models in the natural language generation part of the smart composing framework of consuming the detected important attributes."
|
| 95 |
+
]
|
| 96 |
+
]
|
| 97 |
+
}
|
| 98 |
+
```
|
qasper-0115/instruction.md
ADDED
|
@@ -0,0 +1,98 @@
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|
|
| 1 |
+
Name of Paper: Important Attribute Identification in Knowledge Graph
|
| 2 |
+
|
| 3 |
+
Question: What do you use to calculate word/sub-word embeddings
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"The problem we solve in this paper",
|
| 11 |
+
"Related Research",
|
| 12 |
+
"What we propose and what we have done",
|
| 13 |
+
"Our proposed Method",
|
| 14 |
+
"Application Scenario",
|
| 15 |
+
"FastText Introduction",
|
| 16 |
+
"Matching",
|
| 17 |
+
"Data introduction",
|
| 18 |
+
"Data preprocessing",
|
| 19 |
+
"Proposed method vs previous methods",
|
| 20 |
+
"Result Analysis",
|
| 21 |
+
"Conclusions and Future work "
|
| 22 |
+
],
|
| 23 |
+
"paragraphs": [
|
| 24 |
+
[
|
| 25 |
+
"Knowledge graph(KG) has been proposed for several years and its most prominent application is in web search, for example, Google search triggers a certain entity card when a user's query matches or mentions an entity based on some statistical model. The core potential of a knowledge graph is about its capability of reasoning and inferring, and we have not seen revolutionary breakthrough in such areas yet. One main obstacle is obviously the lack of sufficient knowledge graph data, including entities, entities' descriptions, entities' attributes, and relationship between entities. A full functional knowledge graph supporting general purposed reasoning and inference might still require long years of the community's innovation and hardworking. On the other hand, many less demanding applications have great potential benefiting from the availability of information from the knowledge graph, such as query understanding and document understanding in information retrieval/search engines, simple inference in question answering systems, and easy reasoning in domain-limited decision support tools. Not only academy, but also industry companies have been heavily investing in knowledge graphs, such as Google's knowledge graph, Amazon's product graph, Facebook's Graph API, IBM's Watson, and Microsoft's Satori etc.",
|
| 26 |
+
"In the existing knowledge graph, such as Wikidata and DBpedia, usually attributes do not have order or priorities, and we don't know which attributes are more important and of more interest to users. Such importance score of attributes is a vital piece of information in many applications of knowledge graph. The most important application is the triggered entity card in search engine when a customer's query gets hit for an entity. An entity usually has a large amount of attributes, but an entity card has limited space and can only show the most significant information; attribute importance's presence can make the displaying of an entity card easy to implement. Attribute importance also has great potential of playing a significant role in search engine, how to decide the matching score between the query and attribute values. If the query matches a very important attribute, and the relevance contribution from such a match should be higher than matching an ignorable attribute. Another application is in e-commerce communications, and one buyer initiates a communication cycle with a seller by sending a product enquiry. Writing the enquiry on a mobile phone is inconvenient and automatic composing assistance has great potential of improving customer experience by alleviating the writing burden. In the product enquiry, customers need to specify their requirements and ask questions about products, and their requirements and questions are usually about the most important attributes of the products. If we can identify out important attributes of products, we can help customers to draft the enquiry automatically to reduce their input time."
|
| 27 |
+
],
|
| 28 |
+
[
|
| 29 |
+
"Many proposed approaches formulate the entity attribute ranking problem as a post processing step of automated attribute-value extraction. In BIBREF0 , BIBREF1 , BIBREF2 , Pasca et al. firstly extract potential class-attribute pairs using linguistically motivated patterns from unstructured text including query logs and query sessions, and then score the attributes using the Bayes model. In BIBREF3 , Rahul Rai proposed to identify product attributes from customer online reviews using part-of-speech(POS) tagging patterns, and to evaluate their importance with several different frequency metrics. In BIBREF4 , Lee et al. developed a system to extract concept-attribute pairs from multiple data sources, such as Probase, general web documents, query logs and external knowledge base, and aggregate the weights from different sources into one consistent typicality score using a Ranking SVM model. Those approaches typically suffer from the poor quality of the pattern rules, and the ranking process is used to identify relatively more precise attributes from all attribute candidates.",
|
| 30 |
+
"As for an already existing knowledge graph, there is plenty of work in literature dealing with ranking entities by relevance without or with a query. In BIBREF5 , Li et al. introduced the OntoRank algorithm for ranking the importance of semantic web objects at three levels of granularity: document, terms and RDF graphs. The algorithm is based on the rational surfer model, successfully used in the Swoogle semantic web search engine. In BIBREF6 , Hogan et al. presented an approach that adapted the well-known PageRank/HITS algorithms to semantic web data, which took advantage of property values to rank entities. In BIBREF7 , BIBREF8 , authors also focused on ranking entities, sorting the semantic web resources based on importance, relevance and query length, and aggregating the features together with an overall ranking model.",
|
| 31 |
+
"Just a few works were designated to specifically address the problem of computing attribute rankings in a given Knowledge Graph. Ibminer BIBREF9 introduced a tool for infobox(alias of an entity card) template suggestion, which collected attributes from different sources and then sorted them by popularity based on their co-occurrences in the dataset. In BIBREF10 , using the structured knowledge base, intermediate features were computed, including the importance or popularity of each entity type, IDF computation for each attribute on a global basis, IDF computation for entity types etc., and then the features were aggregated to train a classifier. Also, a similar approach in BIBREF11 was designed with more features extracted from GoogleSuggestChars data. In BIBREF12 , Ali et al. introduced a new set of features that utilizes semantic information about entities as well as information from top-ranked documents from a general search engine. In order to experiment their approach, they collected a dataset by exploiting Wikipedia infoboxes, whose ordering of attributes reflect the collaborative effort of a large community of users, which might not be accurate."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"There have been broad researches on entity detection, relationship extraction, and also missing relationship prediction. For example: BIBREF13 , BIBREF14 and BIBREF15 explained how to construct a knowledge graph and how to perform representation learning on knowledge graphs. Some research has been performed on attribute extraction, such as BIBREF16 and BIBREF4 ; the latter one is quite special that it also simultaneously computes the attribute importance. As for modeling attribute importance for an existing knowledge graph which has completed attribute extractions, we found only a few existing research, all of which used simple co-occurrences to rank entity attributes. In reality, many knowledge graphs do not contain attribute importance information, for example, in the most famous Wikidata, a large amount of entities have many attributes, and it is difficult to know which attributes are significant and deserve more attention. In this research we focus on identifying important attributes in existing knowledge graphs. Specifically, we propose a new method of using extra user generated data source for evaluating the attribute importance, and we use the recently proposed state-of-the-art word/sub-word embedding techniques to match the external data with the attribute definition and values from entities in knowledge graphs. And then we use the statistics obtained from the matching to compare the attribute importance. Our method has general extensibility to any knowledge graph without attribute importance. When there is a possibility of finding external textual data source, our proposed method will work, even if the external data does not exactly match the attribute textual data, since the vector embedding performs semantic matching and does not require exact string matching.",
|
| 35 |
+
"The remaining of the paper is organized as follows: Section SECREF2 explains our proposed method in detail, including what kind of external data is required, and how to process the external data, and also how to perform the semantic matching and how to rank the attributes by statistics. Section SECREF3 introduces our experimentations, including our experimentation setup, data introduction and experimental result compared to other methods we do not employ. Section SECREF3 also briefly introduces our real world application scenario in e-commerce communication. Section SECREF4 draws the conclusion from our experimentations and analysis, and also we point out promising future research directions."
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"In this section, we will introduce our proposed method in detail. We use our application scenario to explain the logic behind the method, but the scope is not limited to our use case, and it is possible to extend to any existing knowledge graph without attribute importance information."
|
| 39 |
+
],
|
| 40 |
+
[
|
| 41 |
+
"Alibaba.com is currently the world's largest cross-border business to business(B2B) E-commerce platform and it supports 17 languages for customers from all over the world. On the website, English is the dorminant language and accounts for around 50% of the traffic. The website has already accumulated a very large knowledge graph of products, and the entity here is the product or the product category; and every entity has lots of information such as the entity name, images and many attributes without ordering information. The entities are also connected by taxonomy structure and similar products usually belong to the same category/sub-category.",
|
| 42 |
+
"Since the B2B procurement usually involves a large amount of money, the business will be a long process beginning with a product enquiry. Generally speaking, when customers are interested in some product, they will start a communication cycle with a seller by sending a product enquiry to the seller. In the product enquiry, customers will specify their requirements and ask questions about the product. Their requirements and questions usually refer to the most important attributes of the product. Fig. FIGREF5 shows an enquery example. Alibaba.com has accumulated tens of millions of product enquires, and we would like to leverage these information, in combination of the product knowledge graph we have, to figure out the most important attributes for each category of products.",
|
| 43 |
+
"In our application scenario, the product knowledge graph is the existing knowledge graph and the enquiry data is the external textual data source. From now on, we will use our application scenario to explain the details of our proposed algorithm.",
|
| 44 |
+
"We propose an unsupervised learning framework for extracting important product attributes from product enquiries. By calculating the semantic similarity between each enquiry sentence and each attribute of the product to which the enquiry corresponds to, we identify the product attributes that the customer cares about most.",
|
| 45 |
+
"The attributes described in the enquiry may contain attribute names or attribute values or other expressions, for example, either the word \u201ccolor\u201d or a color instance word \u201cpurple\u201d is mentioned. Therefore, when calculating the semantic similarity between enquiry sentences and product attributes, we need both attribute names and attribute values. The same as any other knowledge graph, the product attributes in our knowledge graph we use contain noises and mistakes. We need to clean and normalize the attribute data before consuming it. We will introduce the detail of our data cleaning process in Section SECREF14 ."
|
| 46 |
+
],
|
| 47 |
+
[
|
| 48 |
+
"FastText is a library created by the Facebook Research for efficient learning of word representations and sentence classification. Here, we just use the word representation functionality of it.",
|
| 49 |
+
"FastText models morphology by considering subword units, and representing words by a sum of its character n-grams BIBREF17 . In the original model the authors choose to use the binary logistic loss and the loss for a single instance is written as below: INLINEFORM0 ",
|
| 50 |
+
"By denoting the logistic loss function INLINEFORM0 , the loss over a sentence is: INLINEFORM1 ",
|
| 51 |
+
"The scoring function between a word INLINEFORM0 and a context word INLINEFORM1 is: INLINEFORM2 ",
|
| 52 |
+
"In the above functions, INLINEFORM0 is a set of negative examples sampled from the vocabulary, INLINEFORM1 is the set of indices of words surrounding word INLINEFORM2 , INLINEFORM3 is the set of n-grams appearing in word INLINEFORM4 , INLINEFORM5 is the size of the dictionary we have for n-grams, INLINEFORM6 is a vector representation to each n-gram INLINEFORM7 .",
|
| 53 |
+
"Compared with word2vec or glove, FastText has following advantages:",
|
| 54 |
+
"It is able to cover rare words and out-of-vocabulary(OOV) words. Since the basic modeling units in FastText are ngrams, and both rare words and OOV ones can obtain efficient word representations from their composing ngrams. Word2vec and glove both fail to provide accurate vector representations for these words. In our application, the training data is written by end customers, and there are many misspellings which easily become OOV words.",
|
| 55 |
+
"Character n-grams embeddings tend to perform superior to word2vec and glove on smaller datasets.",
|
| 56 |
+
"FastText is more efficient and its training is relatively fast."
|
| 57 |
+
],
|
| 58 |
+
[
|
| 59 |
+
"In this section, how to compute the matching between an enquiry sentence and a product attribute is explained in detail. Our explanation here is for a certain product category, and other categories are the same.",
|
| 60 |
+
"As you can see in Fig. FIGREF12 , each sentence is compared with each attribute of a product category that the product belongs to. We now get a score between a sentence INLINEFORM0 and an attribute INLINEFORM1 , INLINEFORM2 INLINEFORM3 ",
|
| 61 |
+
"where INLINEFORM0 is all the possible values for this INLINEFORM1 , INLINEFORM2 is the word vector for INLINEFORM3 . According to this formula, we can get top two attributes whose scores are above the threshold INLINEFORM4 for each sentence. We choose two attributes instead of one because there may be more than one attribute for each sentence. In addition, some sentences are greetings or self-introduction and do not contain the attribute information of the product, so we require that the score to be higher than a certain threshold."
|
| 62 |
+
],
|
| 63 |
+
[
|
| 64 |
+
"For our knowledge graph data, entity(product) attributes can be roughly divided into clusters of transaction order specific ones and product specific ones, in this paper, we choose the product specific ones for further study. We also need to point out that we only focus on the recommended communication language on the Alibaba.com platform, which is English.",
|
| 65 |
+
"To construct the evaluation dataset, top 14 categories are first chosen based on their business promotion features, and 3 millions typical products under each category were then chosen to form the attribute candidates. After preprocessing and basic filtering, top product specific attributes from the 14 different categories are chosen to be manually labeled by our annotators.",
|
| 66 |
+
"For each category, annotators each are asked to choose at most 10 important attributes from buyers perspective. After all annotators complete their annotations, attributes are then sorted according to the summed votes. In the end, 111 important attributes from the 14 categories are kept for final evaluation.",
|
| 67 |
+
"Outside of the evaluation explained in this paper, we actually have performed the matching on more than 4,000 catetories covering more than 100 million products and more than 20 million enquires. Due to limited annotation resources, we can only sample a small numbered categories(14 here) to evaluate the proposed algorithm here."
|
| 68 |
+
],
|
| 69 |
+
[
|
| 70 |
+
"The product enquiries and attributes data preprocessing is shown in Algorithm 1. algorithmAlgorithm Data Preprocess Algorithm [1] INLINEFORM0 INLINEFORM1 : INLINEFORM2 INLINEFORM3 INLINEFORM4 : INLINEFORM5 Invalid INLINEFORM6 filter INLINEFORM7 Split INLINEFORM8 to sentences sentence INLINEFORM9 in INLINEFORM10 INLINEFORM11 INLINEFORM12 return INLINEFORM13 ",
|
| 71 |
+
"Firstly, for every product enquiry, we convert the original html textual data into the plain text. Secondly we filter out the useless enquires, such as non-English enquires and spams. The regular expressions and spam detection are used to detect non-English enquiries and spams respectively. Thirdly we get sentence list INLINEFORM0 with spliting every enquiry into sentences as described in section 2.2. Then for every sentence INLINEFORM1 in INLINEFORM2 , we need to do extra three processes: a)Spelling Correction. b)Regular Measures and Numbers. c)Stop Words Dropping.",
|
| 72 |
+
"Spelling Correction. Since quite a lot of the product enquires and self-filled attributes were misspelled, we have replaced the exact words by fuzzyfied search using Levenshtein distance. The method uses fuzzyfied search, only if the exact match is not found. Some attributes are actually the same, such as \"type\" and \"product type\", we merge these same attributes by judging whether the attributes are contained.",
|
| 73 |
+
"Regular Measures and Numbers. Attributes of number type have their values composed of numbers and units, such as INLINEFORM0 , INLINEFORM1 , INLINEFORM2 , INLINEFORM3 , etc. We replace all numbers (in any notation, e.g., floating point, scientific, arithmetical expression, etc.) with a unique token ( INLINEFORM4 ). For the same reason, each unit of measure is replaced with a corresponding token, eg., INLINEFORM5 is replaced with centimeter area.",
|
| 74 |
+
"Stop Words Dropping. Stop words appear to be of little value in the proposed matching algorithm. By removing the stop words we can focus on the important words instead. In our business scenario, we built a stop words list for foreign trade e-commerce.",
|
| 75 |
+
"Finally, we get the valid sentences INLINEFORM0 ."
|
| 76 |
+
],
|
| 77 |
+
[
|
| 78 |
+
"The existing co-occurrence methods do not suit our application scenario at all, since exact string matching is too strong a requirement and initial trial has shown its incompetency. In stead we implemented an improved version of their method based on TextRank as our baseline. In addition, we also tested multiple semantic matching algorithms for comparison with our chosen method.",
|
| 79 |
+
"TextRank: TextRank is a graph-based ranking model for text processing. BIBREF18 It is an unsupervised algorithm for keyword extraction. Since product attributes are usually the keywords in enquiries, we can compare these keywords with the category attributes and find the most important attributes. This method consists of three steps. The first step is to merge all enquiries under one category as an article. The second step is to extract the top 50 keywords for each category. The third step is to find the most important attributes by comparing top keywords with category attributes.",
|
| 80 |
+
"Word2vec BIBREF19 : We use the word vector trained by BIBREF19 as the distributed representation of words. Then we get the enquiry sentence representation and category attribute representation. Finally we collect the statistics about the matched attributes of each category, and select the most frequent attributes under the same category.",
|
| 81 |
+
"GloVe BIBREF20 : GloVe is a global log-bilinear regression model for the unsupervised learning of word representations, which utilizes the ratios of word-word co-occurrence probabilities. We use the GloVe method to train the distributed representation of words. And attribute selection procedure is the same as word2vec.",
|
| 82 |
+
"Proposed method: the detail of our proposed algorithm has been carefully explained in Section SECREF2 . There are several thresholds we need to pick in the experimentation setup. Based on trial and error analysis, we choose 0.75 as the sentence and attribute similarity threshold, which balances the precision and recall relatively well. In our application, due to product enquiry length limitation, customers usually don't refer to more than five attributes in their initial approach to the seller, we choose to keep 5 most important attributes for each category.",
|
| 83 |
+
"Evaluation is conducted by comparing the output of the systems with the manual annotated answers, and we calculate the precision and recall rate. INLINEFORM0 INLINEFORM1 ",
|
| 84 |
+
"where INLINEFORM0 is the manually labeled attributes , INLINEFORM1 is the detected important attributes.",
|
| 85 |
+
"Table 1 depicts the algorithm performance of each category and the overall average metrics among all categories for our approach and other methods. It can be observed that our proposed method achieves the best performance. The average F1-measure of our approach is 0.47, while the average F1-measure values of \u201cGloVe\u201d, \u201cword2vect\u201d and \"TextRank\" are 0.46, 0.42 and 0.20 respectively."
|
| 86 |
+
],
|
| 87 |
+
[
|
| 88 |
+
"In all our experiments, we find that FastText method outperforms other methods. By analyzing all results, we observe that semantic similarity based methods are more effective than the previous method which we implemented based on TextRank. This conclusion is understandable because lots of enquiries do not simply mention attribute words exactly, but some semantically related words are also used.",
|
| 89 |
+
"Evaluating FastText, GloVe and word2vec, we show that compared to other word representation learning algorithms, the FastText performs best. We sample and analyze the category attributes and find that many self-filled attributes contain misspellings. The FastText algorithm represents words by a sum of its character n-grams and it is much robust against problems like misspellings. In summary, FastText has greater advantages in dealing with natural language corpus usually with spelling mistakes.",
|
| 90 |
+
"We also applied the detected attributes in the automatic enquiry generation task and we obtained significantly better generated enquiries compared to previous rigid templates. Due to space limitation, we skip the explanation and leave it for future publications."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"In this paper, we proposed a new general method of identifying important attributes for entities from a knowledge graph. This is a relatively new task and our proposed method of using external textual data and performing semantic matching via word/sub-word embeddings obtained better result compared to other work of using naive string matching and counting. In addition, we also successfully applied the detected important attributes in our real world application of smart composing. In summary, the method is extensible to any knowledge graph without attribute importance information and outperforms previous method.",
|
| 94 |
+
"In future work, there are two major areas with potential of improving the detection accuracy. The first one is about sentence splitting. What we are trying to get is semantic cohesive unit, which can be used to match an attribute, and there might be more comprehensive method than the simple splitting by sentence ending punctuations. The second one is about improving the word embedding quality. We have implemented an in-house improved version of Fasttext, which is adapted to our data source. It is highly possible to use the improved word embedding on purpose of obtaining higher semantic matching precision. As for the application, we will try to use more statistical models in the natural language generation part of the smart composing framework of consuming the detected important attributes."
|
| 95 |
+
]
|
| 96 |
+
]
|
| 97 |
+
}
|
| 98 |
+
```
|
qasper-0122/instruction.md
ADDED
|
@@ -0,0 +1,86 @@
|
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|
| 1 |
+
Name of Paper: What Drives the International Development Agenda? An NLP Analysis of the United Nations General Debate 1970-2016
|
| 2 |
+
|
| 3 |
+
Question: How are the main international development topics that states raise identified?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"The UN General Debate and international development",
|
| 12 |
+
"Estimation of topic models",
|
| 13 |
+
"Topics in the UN General Debate",
|
| 14 |
+
"Explaining the rhetoric",
|
| 15 |
+
"Conclusion"
|
| 16 |
+
],
|
| 17 |
+
"paragraphs": [
|
| 18 |
+
[
|
| 19 |
+
"Decisions made in international organisations are fundamental to international development efforts and initiatives. It is in these global governance arenas that the rules of the global economic system, which have a huge impact on development outcomes are agreed on; decisions are made about large-scale funding for development issues, such as health and infrastructure; and key development goals and targets are agreed on, as can be seen with the Millennium Development Goals (MDGs). More generally, international organisations have a profound influence on the ideas that shape international development efforts BIBREF0 .",
|
| 20 |
+
"Yet surprisingly little is known about the agenda-setting process for international development in global governance institutions. This is perhaps best demonstrated by the lack of information on how the different goals and targets of the MDGs were decided, which led to much criticism and concern about the global governance of development BIBREF1 . More generally, we know little about the types of development issues that different countries prioritise, or whether country-specific factors such as wealth or democracy make countries more likely to push for specific development issues to be put on the global political agenda.",
|
| 21 |
+
"The lack of knowledge about the agenda setting process in the global governance of development is in large part due to the absence of obvious data sources on states' preferences about international development issues. To address this gap we employ a novel approach based on the application of natural language processing (NLP) to countries' speeches in the UN. Every September, the heads of state and other high-level country representatives gather in New York at the start of a new session of the United Nations General Assembly (UNGA) and address the Assembly in the General Debate. The General Debate (GD) provides the governments of the almost two hundred UN member states with an opportunity to present their views on key issues in international politics \u2013 including international development. As such, the statements made during GD are an invaluable and, largely untapped, source of information on governments' policy preferences on international development over time.",
|
| 22 |
+
"An important feature of these annual country statements is that they are not institutionally connected to decision-making in the UN. This means that governments face few external constraints when delivering these speeches, enabling them to raise the issues that they consider the most important. Therefore, the General Debate acts \u201cas a barometer of international opinion on important issues, even those not on the agenda for that particular session\u201d BIBREF2 . In fact, the GD is usually the first item for each new session of the UNGA, and as such it provides a forum for governments to identify like-minded members, and to put on the record the issues they feel the UNGA should address. Therefore, the GD can be viewed as a key forum for governments to put different policy issues on international agenda.",
|
| 23 |
+
"We use a new dataset of GD statements from 1970 to 2016, the UN General Debate Corpus (UNGDC), to examine the international development agenda in the UN BIBREF3 . Our application of NLP to these statements focuses in particular on structural topic models (STMs) BIBREF4 . The paper makes two contributions using this approach: (1) It sheds light on the main international development issues that governments prioritise in the UN; and (2) It identifies the key country-specific factors associated with governments discussing development issues in their GD statements."
|
| 24 |
+
],
|
| 25 |
+
[
|
| 26 |
+
"In the analysis we consider the nature of international development issues raised in the UN General Debates, and the effect of structural covariates on the level of developmental rhetoric in the GD statements. To do this, we first implement a structural topic model BIBREF4 . This enables us to identify the key international development topics discussed in the GD. We model topic prevalence in the context of the structural covariates. In addition, we control for region fixed effects and time trend. The aim is to allow the observed metadata to affect the frequency with which a topic is discussed in General Debate speeches. This allows us to test the degree of association between covariates (and region/time effects) and the average proportion of a document discussing a topic."
|
| 27 |
+
],
|
| 28 |
+
[
|
| 29 |
+
"We assess the optimal number of topics that need to be specified for the STM analysis. We follow the recommendations of the original STM paper and focus on exclusivity and semantic coherence measures. BIBREF5 propose semantic coherence measure, which is closely related to point-wise mutual information measure posited by BIBREF6 to evaluate topic quality. BIBREF5 show that semantic coherence corresponds to expert judgments and more general human judgments in Amazon's Mechanical Turk experiments.",
|
| 30 |
+
"Exclusivity scores for each topic follows BIBREF7 . Highly frequent words in a given topic that do not appear very often in other topics are viewed as making that topic exclusive. Cohesive and exclusive topics are more semantically useful. Following BIBREF8 we generate a set of candidate models ranging between 3 and 50 topics. We then plot the exclusivity and semantic coherence (numbers closer to 0 indicate higher coherence), with a linear regression overlaid (Figure FIGREF3 ). Models above the regression line have a \u201cbetter\u201d exclusivity-semantic coherence trade off. We select the 16-topic model, which has the largest positive residual in the regression fit, and provides higher exclusivity at the same level of semantic coherence. The topic quality is usually evaluated by highest probability words, which is presented in Figure FIGREF4 ."
|
| 31 |
+
],
|
| 32 |
+
[
|
| 33 |
+
"Figure FIGREF4 provides a list of the main topics (and the highest probability words associated these topics) that emerge from the STM of UN General Debate statements. In addition to the highest probability words, we use several other measures of key words (not presented here) to interpret the dimensions. This includes the FREX metric (which combines exclusivity and word frequency), the lift (which gives weight to words that appear less frequently in other topics), and the score (which divides the log frequency of the word in the topic by the log frequency of the word in other topics). We provide a brief description of each of the 16 topics here.",
|
| 34 |
+
"Topic 1 - Security and cooperation in Europe.",
|
| 35 |
+
"The first topic is related to issues of security and cooperation, with a focus on Central and Eastern Europe.",
|
| 36 |
+
"Topic 2 - Economic development and the global system.",
|
| 37 |
+
"This topic is related to economic development, particularly around the global economic system. The focus on `trade', `growth', `econom-', `product', `growth', `financ-', and etc. suggests that Topic 2 represent a more traditional view of international development in that the emphasis is specifically on economic processes and relations.",
|
| 38 |
+
"Topic 3 - Nuclear disarmament.",
|
| 39 |
+
"This topic picks up the issue of nuclear weapons, which has been a major issue in the UN since its founding.",
|
| 40 |
+
"Topic 4 - Post-conflict development.",
|
| 41 |
+
"This topic relates to post-conflict development. The countries that feature in the key words (e.g. Rwanda, Liberia, Bosnia) have experienced devastating civil wars, and the emphasis on words such as `develop', `peace', `hope', and `democrac-' suggest that this topic relates to how these countries recover and move forward.",
|
| 42 |
+
"Topic 5 - African independence / decolonisation.",
|
| 43 |
+
"This topic picks up the issue of African decolonisation and independence. It includes the issue of apartheid in South Africa, as well as racism and imperialism more broadly.",
|
| 44 |
+
"Topic 6 - Africa.",
|
| 45 |
+
"While the previous topic focused explicitly on issues of African independence and decolonisation, this topic more generally picks up issues linked to Africa, including peace, governance, security, and development.",
|
| 46 |
+
"Topic 7 - Sustainable development.",
|
| 47 |
+
"This topic centres on sustainable development, picking up various issues linked to development and climate change. In contrast to Topic 2, this topic includes some of the newer issues that have emerged in the international development agenda, such as sustainability, gender, education, work and the MDGs.",
|
| 48 |
+
"Topic 8 - Functional topic.",
|
| 49 |
+
"This topic appears to be comprised of functional or process-oriented words e.g. `problem', `solution', `effort', `general', etc.",
|
| 50 |
+
"Topic 9 - War.",
|
| 51 |
+
"This topic directly relates to issues of war. The key words appear to be linked to discussions around ongoing wars.",
|
| 52 |
+
"Topic 10 - Conflict in the Middle East.",
|
| 53 |
+
"This topic clearly picks up issues related to the Middle East \u2013 particularly around peace and conflict in the Middle East.",
|
| 54 |
+
"Topic 11 - Latin America.",
|
| 55 |
+
"This is another topic with a regional focus, picking up on issues related to Latin America.",
|
| 56 |
+
"Topic 12 - Commonwealth.",
|
| 57 |
+
"This is another of the less obvious topics to emerge from the STM in that the key words cover a wide range of issues. However, the places listed (e.g. Australia, Sri Lanka, Papua New Guinea) suggest the topic is related to the Commonwealth (or former British colonies).",
|
| 58 |
+
"Topic 13 - International security.",
|
| 59 |
+
"This topic broadly captures international security issues (e.g. terrorism, conflict, peace) and in particularly the international response to security threats, such as the deployment of peacekeepers.",
|
| 60 |
+
"Topic 14 - International law.",
|
| 61 |
+
"This topic picks up issues related to international law, particularly connected to territorial disputes.",
|
| 62 |
+
"Topic 15 - Decolonisation.",
|
| 63 |
+
"This topic relates more broadly to decolonisation. As well as specific mention of decolonisation, the key words include a range of issues and places linked to the decolonisation process.",
|
| 64 |
+
"Topic 16 - Cold War.",
|
| 65 |
+
"This is another of the less tightly defined topics. The topics appears to pick up issues that are broadly related to the Cold War. There is specific mention of the Soviet Union, and detente, as well as issues such as nuclear weapons, and the Helsinki Accords.",
|
| 66 |
+
"Based on these topics, we examine Topic 2 and Topic 7 as the principal \u201cinternational development\u201d topics. While a number of other topics \u2013 for example post-conflict development, Africa, Latin America, etc. \u2013 are related to development issues, Topic 2 and Topic 7 most directly capture aspects of international development. We consider these two topics more closely by contrasting the main words linked to these two topics. In Figure FIGREF6 , the word clouds show the 50 words most likely to mentioned in relation to each of the topics.",
|
| 67 |
+
"The word clouds provide further support for Topic 2 representing a more traditional view of international development focusing on economic processes. In addition to a strong emphasis on 'econom-', other key words, such as `trade', `debt', `market', `growth', `industri-', `financi-', `technolog-', `product', and `argicultur-', demonstrate the narrower economic focus on international development captured by Topic 2. In contrast, Topic 7 provides a much broader focus on development, with key words including `climat-', `sustain', `environ-', `educ-', `health', `women', `work', `mdgs', `peac-', `govern-', and `right'. Therefore, Topic 7 captures many of the issues that feature in the recent Sustainable Development Goals (SDGs) agenda BIBREF9 .",
|
| 68 |
+
"Figure FIGREF7 calculates the difference in probability of a word for the two topics, normalized by the maximum difference in probability of any word between the two topics. The figure demonstrates that while there is a much high probability of words, such as `econom-', `trade', and even `develop-' being used to discuss Topic 2; words such as `climat-', `govern-', `sustain', `goal', and `support' being used in association with Topic 7. This provides further support for the Topic 2 representing a more economistic view of international development, while Topic 7 relating to a broader sustainable development agenda.",
|
| 69 |
+
"We also assess the relationship between topics in the STM framework, which allows correlations between topics to be examined. This is shown in the network of topics in Figure FIGREF8 . The figure shows that Topic 2 and Topic 7 are closely related, which we would expect as they both deal with international development (and share key words on development, such as `develop-', `povert-', etc.). It is also worth noting that while Topic 2 is more closely correlated with the Latin America topic (Topic 11), Topic 7 is more directly correlated with the Africa topic (Topic 6)."
|
| 70 |
+
],
|
| 71 |
+
[
|
| 72 |
+
"We next look at the relationship between topic proportions and structural factors. The data for these structural covariates is taken from the World Bank's World Development Indicators (WDI) unless otherwise stated. Confidence intervals produced by the method of composition in STM allow us to pick up statistical uncertainty in the linear regression model.",
|
| 73 |
+
"Figure FIGREF9 demonstrates the effect of wealth (GDP per capita) on the the extent to which states discuss the two international development topics in their GD statements. The figure shows that the relationship between wealth and the topic proportions linked to international development differs across Topic 2 and Topic 7. Discussion of Topic 2 (economic development) remains far more constant across different levels of wealth than Topic 7. The poorest states tend to discuss both topics more than other developing nations. However, this effect is larger for Topic 7. There is a decline in the proportion of both topics as countries become wealthier until around $30,000 when there is an increase in discussion of Topic 7. There is a further pronounced increase in the extent countries discuss Topic 7 at around $60,000 per capita. However, there is a decline in expected topic proportions for both Topic 2 and Topic 7 for the very wealthiest countries.",
|
| 74 |
+
"Figure FIGREF10 shows the expected topic proportions for Topic 2 and Topic 7 associated with different population sizes. The figure shows a slight surge in the discussion of both development topics for countries with the very smallest populations. This reflects the significant amount of discussion of development issues, particularly sustainable development (Topic 7) by the small island developing states (SIDs). The discussion of Topic 2 remains relatively constant across different population sizes, with a slight increase in the expected topic proportion for the countries with the very largest populations. However, with Topic 7 there is an increase in expected topic proportion until countries have a population of around 300 million, after which there is a decline in discussion of Topic 7. For countries with populations larger than 500 million there is no effect of population on discussion of Topic 7. It is only with the very largest populations that we see a positive effect on discussion of Topic 7.",
|
| 75 |
+
"We would also expect the extent to which states discuss international development in their GD statements to be impacted by the amount of aid or official development assistance (ODA) they receive. Figure FIGREF11 plots the expected topic proportion according to the amount of ODA countries receive. Broadly-speaking the discussion of development topics remains largely constant across different levels of ODA received. There is, however, a slight increase in the expected topic proportions of Topic 7 according to the amount of ODA received. It is also worth noting the spikes in discussion of Topic 2 and Topic 7 for countries that receive negative levels of ODA. These are countries that are effectively repaying more in loans to lenders than they are receiving in ODA. These countries appear to raise development issues far more in their GD statements, which is perhaps not altogether surprising.",
|
| 76 |
+
"We also consider the effects of democracy on the expected topic proportions of both development topics using the Polity IV measure of democracy BIBREF10 . Figure FIGREF12 shows the extent to which states discuss the international development topics according to their level of democracy. Discussion of Topic 2 is fairly constant across different levels of democracy (although there are some slight fluctuations). However, the extent to which states discuss Topic 7 (sustainable development) varies considerably across different levels of democracy. Somewhat surprisingly the most autocratic states tend to discuss Topic 7 more than the slightly less autocratic states. This may be because highly autocratic governments choose to discuss development and environmental issues to avoid a focus on democracy and human rights. There is then an increase in the expected topic proportion for Topic 7 as levels of democracy increase reaching a peak at around 5 on the Polity scale, after this there is a gradual decline in discussion of Topic 7. This would suggest that democratizing or semi-democratic countries (which are more likely to be developing countries with democratic institutions) discuss sustainable development more than established democracies (that are more likely to be developed countries).",
|
| 77 |
+
"We also plot the results of the analysis as the difference in topic proportions for two different values of the effect of conflict. Our measure of whether a country is experiencing a civil conflict comes from the UCDP/PRIO Armed Conflict Dataset BIBREF11 . Point estimates and 95% confidence intervals are plotted in Figure FIGREF13 . The figure shows that conflict affects only Topic 7 and not Topic 2. Countries experiencing conflict are less likely to discuss Topic 7 (sustainable development) than countries not experiencing conflict. The most likely explanation is that these countries are more likely to devote a greater proportion of their annual statements to discussing issues around conflict and security than development. The fact that there is no effect of conflict on Topic 2 is interesting in this regard.",
|
| 78 |
+
"Finally, we consider regional effects in Figure FIGREF14 . We use the World Bank's classifications of regions: Latin America and the Caribbean (LCN), South Asia (SAS), Sub-Saharan Africa (SSA), Europe and Central Asia (ECS), Middle East and North Africa (MEA), East Asia and the Pacific (EAS), North America (NAC). The figure shows that states in South Asia, and Latin America and the Caribbean are likely to discuss Topic 2 the most. States in South Asia and East Asia and the Pacific discuss Topic 7 the most. The figure shows that countries in North America are likely to speak about Topic 7 least.",
|
| 79 |
+
"The analysis of discussion of international development in annual UN General Debate statements therefore uncovers two principle development topics: economic development and sustainable development. We find that discussion of Topic 2 is not significantly impacted by country-specific factors, such as wealth, population, democracy, levels of ODA, and conflict (although there are regional effects). However, we find that the extent to which countries discuss sustainable development (Topic 7) in their annual GD statements varies considerably according to these different structural factors. The results suggest that broadly-speaking we do not observe linear trends in the relationship between these country-specific factors and discussion of Topic 7. Instead, we find that there are significant fluctuations in the relationship between factors such as wealth, democracy, etc., and the extent to which these states discuss sustainable development in their GD statements. These relationships require further analysis and exploration."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"Despite decisions taken in international organisations having a huge impact on development initiatives and outcomes, we know relatively little about the agenda-setting process around the global governance of development. Using a novel approach that applies NLP methods to a new dataset of speeches in the UN General Debate, this paper has uncovered the main development topics discussed by governments in the UN, and the structural factors that influence the degree to which governments discuss international development. In doing so, the paper has shed some light on state preferences regarding the international development agenda in the UN. The paper more broadly demonstrates how text analytic approaches can help us to better understand different aspects of global governance."
|
| 83 |
+
]
|
| 84 |
+
]
|
| 85 |
+
}
|
| 86 |
+
```
|
qasper-0123/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: QnAMaker: Data to Bot in 2 Minutes
|
| 2 |
+
|
| 3 |
+
Question: What experiments do the authors present to validate their system?
|
qasper-0124/instruction.md
ADDED
|
@@ -0,0 +1,93 @@
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|
| 1 |
+
Name of Paper: QnAMaker: Data to Bot in 2 Minutes
|
| 2 |
+
|
| 3 |
+
Question: How does the conversation layer work?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"System description ::: Architecture",
|
| 12 |
+
"System description ::: Bot Development Process",
|
| 13 |
+
"System description ::: Extraction",
|
| 14 |
+
"System description ::: Retrieval And Ranking",
|
| 15 |
+
"System description ::: Retrieval And Ranking ::: Pre-Processing",
|
| 16 |
+
"System description ::: Retrieval And Ranking ::: Features",
|
| 17 |
+
"System description ::: Retrieval And Ranking ::: Contextual Features",
|
| 18 |
+
"System description ::: Retrieval And Ranking ::: Modeling and Training",
|
| 19 |
+
"System description ::: Persona Based Chit-Chat",
|
| 20 |
+
"System description ::: Active Learning",
|
| 21 |
+
"Evaluation and Insights",
|
| 22 |
+
"Demonstration",
|
| 23 |
+
"Future Work"
|
| 24 |
+
],
|
| 25 |
+
"paragraphs": [
|
| 26 |
+
[
|
| 27 |
+
"QnAMaker aims to simplify the process of bot creation by extracting Question-Answer (QA) pairs from data given by users into a Knowledge Base (KB) and providing a conversational layer over it. KB here refers to one instance of azure search index, where the extracted QA are stored. Whenever a developer creates a KB using QnAMaker, they automatically get all NLP capabilities required to answer user's queries. There are other systems such as Google's Dialogflow, IBM's Watson Discovery which tries to solve this problem. QnAMaker provides unique features for the ease of development such as the ability to add a persona-based chit-chat layer on top of the bot. Additionally, bot developers get automatic feedback from the system based on end-user traffic and interaction which helps them in enriching the KB; we call this feature active-learning. Our system also allows user to add Multi-Turn structure to KB using hierarchical extraction and contextual ranking. QnAMaker today supports over 35 languages, and is the only system among its competitors to follow a Server-Client architecture; all the KB data rests only in the client's subscription, giving users total control over their data. QnAMaker is part of Microsoft Cognitive Service and currently runs using the Microsoft Azure Stack."
|
| 28 |
+
],
|
| 29 |
+
[
|
| 30 |
+
"As shown in Figure FIGREF4, humans can have two different kinds of roles in the system: Bot-Developers who want to create a bot using the data they have, and End-Users who will chat with the bot(s) created by bot-developers. The components involved in the process are:",
|
| 31 |
+
"QnAMaker Portal: This is the Graphical User Interface (GUI) for using QnAMaker. This website is designed to ease the use of management APIs. It also provides a test pane.",
|
| 32 |
+
"QnaMaker Management APIs: This is used for the extraction of Question-Answer (QA) pairs from semi-structured content. It then passes these QA pairs to the web app to create the Knowledge Base Index.",
|
| 33 |
+
"Azure Search Index: Stores the KB with questions and answers as indexable columns, thus acting as a retrieval layer.",
|
| 34 |
+
"QnaMaker WebApp: Acts as a layer between the Bot, Management APIs, and Azure Search Index. WebApp does ranking on top of retrieved results. WebApp also handles feedback management for active learning.",
|
| 35 |
+
"Bot: Calls the WebApp with the User's query to get results."
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"Creating a bot is a 3-step process for a bot developer:",
|
| 39 |
+
"Create a QnaMaker Resource in Azure: This creates a WebApp with binaries required to run QnAMaker. It also creates an Azure Search Service for populating the index with any given knowledge base, extracted from user data",
|
| 40 |
+
"Use Management APIs to Create/Update/Delete your KB: The Create API automatically extracts the QA pairs and sends the Content to WebApp, which indexes it in Azure Search Index. Developers can also add persona-based chat content and synonyms while creating and updating their KBs.",
|
| 41 |
+
"Bot Creation: Create a bot using any framework and call the WebApp hosted in Azure to get your queries answered. There are Bot-Framework templates provided for the same."
|
| 42 |
+
],
|
| 43 |
+
[
|
| 44 |
+
"The Extraction component is responsible for understanding a given document and extracting potential QA pairs. These QA pairs are in turn used to create a KB to be consumed later on by the QnAMaker WebApp to answer user queries. First, the basic blocks from given documents such as text, lines are extracted. Then the layout of the document such as columns, tables, lists, paragraphs, etc is extracted. This is done using Recursive X-Y cut BIBREF0. Following Layout Understanding, each element is tagged as headers, footers, table of content, index, watermark, table, image, table caption, image caption, heading, heading level, and answers. Agglomerative clustering BIBREF1 is used to identify heading and hierarchy to form an intent tree. Leaf nodes from the hierarchy are considered as QA pairs. In the end, the intent tree is further augmented with entities using CRF-based sequence labeling. Intents that are repeated in and across documents are further augmented with their parent intent, adding more context to resolve potential ambiguity."
|
| 45 |
+
],
|
| 46 |
+
[
|
| 47 |
+
"QnAMaker uses Azure Search Index as it's retrieval layer, followed by re-ranking on top of retrieved results (Figure FIGREF21). Azure Search is based on inverted indexing and TF-IDF scores. Azure Search provides fuzzy matching based on edit-distance, thus making retrieval robust to spelling mistakes. It also incorporates lemmatization and normalization. These indexes can scale up to millions of documents, lowering the burden on QnAMaker WebApp which gets less than 100 results to re-rank.",
|
| 48 |
+
"Different customers may use QnAMaker for different scenarios such as banking task completion, answering FAQs on company policies, or fun and engagement. The number of QAs, length of questions and answers, number of alternate questions per QA can vary significantly across different types of content. Thus, the ranker model needs to use features that are generic enough to be relevant across all use cases."
|
| 49 |
+
],
|
| 50 |
+
[
|
| 51 |
+
"The pre-processing layer uses components such as Language Detection, Lemmatization, Speller, and Word Breaker to normalize user queries. It also removes junk characters and stop-words from the user's query."
|
| 52 |
+
],
|
| 53 |
+
[
|
| 54 |
+
"Going into granular features and the exact empirical formulas used is out of the scope of this paper. The broad level features used while ranking are:",
|
| 55 |
+
"WordNet: There are various features generated using WordNet BIBREF2 matching with questions and answers. This takes care of word-level semantics. For instance, if there is information about \u201cprice of furniture\" in a KB and the end-user asks about \u201cprice of table\", the user will likely get a relevant answer. The scores of these WordNet features are calculated as a function of:",
|
| 56 |
+
"Distance of 2 words in the WordNet graph",
|
| 57 |
+
"Distance of Lowest Common Hypernym from the root",
|
| 58 |
+
"Knowledge-Base word importance (Local IDFs)",
|
| 59 |
+
"Global word importance (Global IDFs)",
|
| 60 |
+
"This is the most important feature in our model as it has the highest relative feature gain.",
|
| 61 |
+
"CDSSM: Convolutional Deep Structured Semantic Models BIBREF3 are used for sentence-level semantic matching. This is a dual encoder model that converts text strings (sentences, queries, predicates, entity mentions, etc) into their vector representations. These models are trained using millions of Bing Query Title Click-Through data. Using the source-model for vectorizing user query and target-model for vectorizing answer, we compute the cosine similarity between these two vectors, giving the relevance of answer corresponding to the query.",
|
| 62 |
+
"TF-IDF: Though sentence-to-vector models are trained on huge datasets, they fail to effectively disambiguate KB specific data. This is where a standard TF-IDF BIBREF4 featurizer with local and global IDFs helps."
|
| 63 |
+
],
|
| 64 |
+
[
|
| 65 |
+
"We extend the features for contextual ranking by modifying the candidate QAs and user query in these ways:",
|
| 66 |
+
"$Query_{modified}$ = Query + Previous Answer; For instance, if user query is \u201cyes\" and the previous answer is \u201cdo you want to know about XYZ\", the current query becomes \u201cdo you want to know about XYZ yes\".",
|
| 67 |
+
"Candidate QnA pairs are appended with its parent Questions and Answers; no contextual information is used from the user's query. For instance, if a candidate QnA has a question \u201cbenefits\" and its parent question was \u201cknow about XYZ\", the candidate QA's question is changed to \u201cknow about XYZ benefits\".",
|
| 68 |
+
"The features mentioned in Section SECREF20 are calculated for the above combinations also. These features carry contextual information."
|
| 69 |
+
],
|
| 70 |
+
[
|
| 71 |
+
"We use gradient-boosted decision trees as our ranking model to combine all the features. Early stopping BIBREF5 based on Generality-to-Progress ratio is used to decide the number of step trees and Tolerant Pruning BIBREF6 helps prevent overfitting. We follow incremental training if there is small changes in features or training data so that the score distribution is not changed drastically."
|
| 72 |
+
],
|
| 73 |
+
[
|
| 74 |
+
"We add support for bot-developers to directly enable handling chit-chat queries like \u201chi\", \u201cthank you\", \u201cwhat's up\" in their QnAMaker bots. In addition to chit-chat, we also give bot developers the flexibility to ground responses for such queries in a specific personality: professional, witty, friendly, caring, or enthusiastic. For example, the \u201cHumorous\" personality can be used for a casual bot, whereas a \u201cProfessional\" personality is more suited in case of banking FAQs or task-completion bots. There is a list of 100+ predefined intents BIBREF7. There is a curated list of queries for each of these intents, along with a separate query understanding layer for ranking these intents. The arbitration between chit-chat answers and user's knowledge base answers is handled by using a chat-domain classifier BIBREF8."
|
| 75 |
+
],
|
| 76 |
+
[
|
| 77 |
+
"The majority of the KBs are created using existing FAQ pages or manuals but to improve the quality it requires effort from the developers. Active learning generates suggestions based on end-user feedback as well as ranker's implicit signals. For instance, if for a query, CDSSM feature was confident that one QnA should be ranked higher whereas wordnet feature thought other QnA should be ranked higher, active learning system will try to disambiguate it by showing this as a suggestion to the bot developer. To avoid showing similar suggestions to developers, DB-Scan clustering is done which optimizes the number of suggestions shown."
|
| 78 |
+
],
|
| 79 |
+
[
|
| 80 |
+
"QnAMaker is not domain-specific and can be used for any type of data. To support this claim, we measure our system's performance for datasets across various domains. The evaluations are done by managed judges who understands the knowledge base and then judge user queries relevance to the QA pairs (binary labels). Each query-QA pair is judged by two judges. We filter out data for which judges do not agree on the label. Chit-chat in itself can be considered as a domain. Thus, we evaluate performance on given KB both with and without chit-chat data (last two rows in Table TABREF19), as well as performance on just chit-chat data (2nd row in Table TABREF19). Hybrid of deep learning(CDSSM) and machine learning features give our ranking model low computation cost, high explainability and significant F1/AUC score. Based on QnAMaker usage, we observed these trends:",
|
| 81 |
+
"Around 27% of the knowledge bases created use pre-built persona-based chitchat, out of which, $\\sim $4% of the knowledge bases are created for chit-chat alone. The highest used personality is Professional which is used in 9% knowledge bases.",
|
| 82 |
+
"Around $\\sim $25% developers have enabled active learning suggestions. The acceptance to reject ratio for active learning suggestions is 0.31.",
|
| 83 |
+
"25.5% of the knowledge bases use one URL as a source while creation. $\\sim $41% of the knowledge bases created use different sources like multiple URLs. 15.19% of the knowledge bases use both URL and editorial content as sources. Rest use just editorial content."
|
| 84 |
+
],
|
| 85 |
+
[
|
| 86 |
+
"We demonstrate QnAMaker: a service to add a conversational layer over semi-structured user data. In addition to query-answering, we support novel features like personality-grounded chit-chat, active learning based on user-interaction feedback (Figure FIGREF40), and hierarchical extraction for multi-turn conversations (Figure FIGREF41). The goal of the demonstration will be to show how easy it is to create an intelligent bot using QnAMaker. All the demonstrations will be done on the production website Demo Video can be seen here."
|
| 87 |
+
],
|
| 88 |
+
[
|
| 89 |
+
"The system currently doesn't highlight the answer span and does not generate answers taking the KB as grounding. We will be soon supporting Answer Span BIBREF9 and KB-grounded response generation BIBREF10 in QnAMaker. We are also working on user-defined personas for chit-chat (automatically learned from user-documents). We aim to enhance our extraction to be able to work for any unstructured document as well as images. We are also experimenting on improving our ranking system by using semantic vector-based search as our retrieval and transformer-based models for re-ranking."
|
| 90 |
+
]
|
| 91 |
+
]
|
| 92 |
+
}
|
| 93 |
+
```
|
qasper-0125/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: QnAMaker: Data to Bot in 2 Minutes
|
| 2 |
+
|
| 3 |
+
Question: What components is the QnAMaker composed of?
|
qasper-0140/instruction.md
ADDED
|
@@ -0,0 +1,110 @@
|
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|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: Procedural Reasoning Networks for Understanding Multimodal Procedures
|
| 2 |
+
|
| 3 |
+
Question: How better is accuracy of new model compared to previously reported models?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Visual Reasoning in RecipeQA",
|
| 12 |
+
"Procedural Reasoning Networks",
|
| 13 |
+
"Procedural Reasoning Networks ::: Input Module",
|
| 14 |
+
"Procedural Reasoning Networks ::: Reasoning Module",
|
| 15 |
+
"Procedural Reasoning Networks ::: Attention Module",
|
| 16 |
+
"Procedural Reasoning Networks ::: Modeling Module",
|
| 17 |
+
"Procedural Reasoning Networks ::: Output Module",
|
| 18 |
+
"Experiments",
|
| 19 |
+
"Experiments ::: Entity Extraction",
|
| 20 |
+
"Experiments ::: Training Details",
|
| 21 |
+
"Experiments ::: Baselines",
|
| 22 |
+
"Experiments ::: Results",
|
| 23 |
+
"Related Work",
|
| 24 |
+
"Conclusion",
|
| 25 |
+
"Acknowledgements"
|
| 26 |
+
],
|
| 27 |
+
"paragraphs": [
|
| 28 |
+
[
|
| 29 |
+
"A great deal of commonsense knowledge about the world we live is procedural in nature and involves steps that show ways to achieve specific goals. Understanding and reasoning about procedural texts (e.g. cooking recipes, how-to guides, scientific processes) are very hard for machines as it demands modeling the intrinsic dynamics of the procedures BIBREF0, BIBREF1, BIBREF2. That is, one must be aware of the entities present in the text, infer relations among them and even anticipate changes in the states of the entities after each action. For example, consider the cheeseburger recipe presented in Fig. FIGREF2. The instruction \u201csalt and pepper each patty and cook for 2 to 3 minutes on the first side\u201d in Step 5 entails mixing three basic ingredients, the ground beef, salt and pepper, together and then applying heat to the mix, which in turn causes chemical changes that alter both the appearance and the taste. From a natural language understanding perspective, the main difficulty arises when a model sees the word patty again at a later stage of the recipe. It still corresponds to the same entity, but its form is totally different.",
|
| 30 |
+
"Over the past few years, many new datasets and approaches have been proposed that address this inherently hard problem BIBREF0, BIBREF1, BIBREF3, BIBREF4. To mitigate the aforementioned challenges, the existing works rely mostly on heavy supervision and focus on predicting the individual state changes of entities at each step. Although these models can accurately learn to make local predictions, they may lack global consistency BIBREF3, BIBREF4, not to mention that building such annotated corpora is very labor-intensive. In this work, we take a different direction and explore the problem from a multimodal standpoint. Our basic motivation, as illustrated in Fig. FIGREF2, is that accompanying images provide complementary cues about causal effects and state changes. For instance, it is quite easy to distinguish raw meat from cooked one in visual domain.",
|
| 31 |
+
"In particular, we take advantage of recently proposed RecipeQA dataset BIBREF2, a dataset for multimodal comprehension of cooking recipes, and ask whether it is possible to have a model which employs dynamic representations of entities in answering questions that require multimodal understanding of procedures. To this end, inspired from BIBREF5, we propose Procedural Reasoning Networks (PRN) that incorporates entities into the comprehension process and allows to keep track of entities, understand their interactions and accordingly update their states across time. We report that our proposed approach significantly improves upon previously published results on visual reasoning tasks in RecipeQA, which test understanding causal and temporal relations from images and text. We further show that the dynamic entity representations can capture semantics of the state information in the corresponding steps."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"In our study, we particularly focus on the visual reasoning tasks of RecipeQA, namely visual cloze, visual coherence, and visual ordering tasks, each of which examines a different reasoning skill. We briefly describe these tasks below.",
|
| 35 |
+
"Visual Cloze. In the visual cloze task, the question is formed by a sequence of four images from consecutive steps of a recipe where one of them is replaced by a placeholder. A model should select the correct one from a multiple-choice list of four answer candidates to fill in the missing piece. In that regard, the task inherently requires aligning visual and textual information and understanding temporal relationships between the cooking actions and the entities.",
|
| 36 |
+
"Visual Coherence. The visual coherence task tests the ability to identify the image within a sequence of four images that is inconsistent with the text instructions of a cooking recipe. To succeed in this task, a model should have a clear understanding of the procedure described in the recipe and at the same time connect language and vision.",
|
| 37 |
+
"Visual Ordering. The visual ordering task is about grasping the temporal flow of visual events with the help of the given recipe text. The questions show a set of four images from the recipe and the task is to sort jumbled images into the correct order. Here, a model needs to infer the temporal relations between the images and align them with the recipe steps."
|
| 38 |
+
],
|
| 39 |
+
[
|
| 40 |
+
"In the following, we explain our Procedural Reasoning Networks model. Its architecture is based on a bi-directional attention flow (BiDAF) model BIBREF6, but also equipped with an explicit reasoning module that acts on entity-specific relational memory units. Fig. FIGREF4 shows an overview of the network architecture. It consists of five main modules: An input module, an attention module, a reasoning module, a modeling module, and an output module. Note that the question answering tasks we consider here are multimodal in that while the context is a procedural text, the question and the multiple choice answers are composed of images.",
|
| 41 |
+
"Input Module extracts vector representations of inputs at different levels of granularity by using several different encoders.",
|
| 42 |
+
"Reasoning Module scans the procedural text and tracks the states of the entities and their relations through a recurrent relational memory core unit BIBREF5.",
|
| 43 |
+
"Attention Module computes context-aware query vectors and query-aware context vectors as well as query-aware memory vectors.",
|
| 44 |
+
"Modeling Module employs two multi-layered RNNs to encode previous layers outputs.",
|
| 45 |
+
"Output Module scores a candidate answer from the given multiple-choice list.",
|
| 46 |
+
"At a high level, as the model is reading the cooking recipe, it continually updates the internal memory representations of the entities (ingredients) based on the content of each step \u2013 it keeps track of changes in the states of the entities, providing an entity-centric summary of the recipe. The response to a question and a possible answer depends on the representation of the recipe text as well as the last states of the entities. All this happens in a series of implicit relational reasoning steps and there is no need for explicitly encoding the state in terms of a predefined vocabulary."
|
| 47 |
+
],
|
| 48 |
+
[
|
| 49 |
+
"Let the triple $(\\mathbf {R},\\mathbf {Q},\\mathbf {A})$ be a sample input. Here, $\\mathbf {R}$ denotes the input recipe which contains textual instructions composed of $N$ words in total. $\\mathbf {Q}$ represents the question that consists of a sequence of $M$ images. $\\mathbf {A}$ denotes an answer that is either a single image or a series of $L$ images depending on the reasoning task. In particular, for the visual cloze and the visual coherence type questions, the answer contains a single image ($L=1$) and for the visual ordering task, it includes a sequence.",
|
| 50 |
+
"We encode the input recipe $\\mathbf {R}$ at character, word, and step levels. Character-level embedding layer uses a convolutional neural network, namely CharCNN model by BIBREF7, which outputs character level embeddings for each word and alleviates the issue of out-of-vocabulary (OOV) words. In word embedding layer, we use a pretrained GloVe model BIBREF8 and extract word-level embeddings. The concatenation of the character and the word embeddings are then fed to a two-layer highway network BIBREF10 to obtain a contextual embedding for each word in the recipe. This results in the matrix $\\mathbf {R}^{\\prime } \\in \\mathbb {R}^{2d \\times N}$.",
|
| 51 |
+
"On top of these layers, we have another layer that encodes the steps of the recipe in an individual manner. Specifically, we obtain a step-level contextual embedding of the input recipe containing $T$ steps as $\\mathcal {S}=(\\mathbf {s}_1,\\mathbf {s}_2,\\dots ,\\mathbf {s}_T)$ where $\\mathbf {s}_i$ represents the final state of a BiLSTM encoding the $i$-th step of the recipe obtained from the character and word-level embeddings of the tokens exist in the corresponding step.",
|
| 52 |
+
"We represent both the question $\\mathbf {Q}$ and the answer $\\mathbf {A}$ in terms of visual embeddings. Here, we employ a pretrained ResNet-50 model BIBREF11 trained on ImageNet dataset BIBREF12 and represent each image as a real-valued 2048-d vector using features from the penultimate average-pool layer. Then these embeddings are passed first to a multilayer perceptron (MLP) and then its outputs are fed to a BiLSTM. We then form a matrix $\\mathbf {Q}^{\\prime } \\in \\mathbb {R}^{2d \\times M}$ for the question by concatenating the cell states of the BiLSTM. For the visual ordering task, to represent the sequence of images in the answer with a single vector, we additionally use a BiLSTM and define the answering embedding by the summation of the cell states of the BiLSTM. Finally, for all tasks, these computations produce answer embeddings denoted by $\\mathbf {a} \\in \\mathbb {R}^{2d \\times 1}$."
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"As mentioned before, comprehending a cooking recipe is mostly about entities (basic ingredients) and actions (cooking activities) described in the recipe instructions. Each action leads to changes in the states of the entities, which usually affects their visual characteristics. A change rarely occurs in isolation; in most cases, the action affects multiple entities at once. Hence, in our reasoning module, we have an explicit memory component implemented with relational memory units BIBREF5. This helps us to keep track of the entities, their state changes and their relations in relation to each other over the course of the recipe (see Fig. FIGREF14). As we will examine in more detail in Section SECREF4, it also greatly improves the interpretability of model outputs.",
|
| 56 |
+
"Specifically, we set up the memory with a memory matrix $\\mathbf {E} \\in \\mathbb {R}^{d_E \\times K}$ by extracting $K$ entities (ingredients) from the first step of the recipe. We initialize each memory cell $\\mathbf {e}_i$ representing a specific entity by its CharCNN and pre-trained GloVe embeddings. From now on, we will use the terms memory cells and entities interchangeably throughout the paper. Since the input recipe is given in the form of a procedural text decomposed into a number of steps, we update the memory cells after each step, reflecting the state changes happened on the entities. This update procedure is modelled via a relational recurrent neural network (R-RNN), recently proposed by BIBREF5. It is built on a 2-dimensional LSTM model whose matrix of cell states represent our memory matrix $\\mathbf {E}$. Here, each row $i$ of the matrix $\\mathbf {E}$ refers to a specific entity $\\mathbf {e}_i$ and is updated after each recipe step $t$ as follows:",
|
| 57 |
+
"where $\\mathbf {s}_{t}$ denotes the embedding of recipe step $t$ and $\\mathbf {\\phi }_{i,t}=(\\mathbf {h}_{i,t},\\mathbf {e}_{i,t})$ is the cell state of the R-RNN at step $t$ with $\\mathbf {h}_{i,t}$ and $\\mathbf {e}_{i,t}$ being the $i$-th row of the hidden state of the R-RNN and the dynamic representation of entity $\\mathbf {e}_{i}$ at the step $t$, respectively. The R-RNN model exploits a multi-headed self-attention mechanism BIBREF13 that allows memory cells to interact with each other and attend multiple locations simultaneously during the update phase.",
|
| 58 |
+
"In Fig. FIGREF14, we illustrate how this interaction takes place in our relational memory module by considering a sample cooking recipe and by presenting how the attention matrix changes throughout the recipe. In particular, the attention matrix at a specific time shows the attention flow from one entity (memory cell) to another along with the attention weights to the corresponding recipe step (offset column). The color intensity shows the magnitude of the attention weights. As can be seen from the figure, the internal representations of the entities are actively updated at each step. Moreover, as argued in BIBREF5, this can be interpreted as a form of relational reasoning as each update on a specific memory cell is operated in relation to others. Here, we should note that it is often difficult to make sense of these attention weights. However, we observe that the attention matrix changes very gradually near the completion of the recipe."
|
| 59 |
+
],
|
| 60 |
+
[
|
| 61 |
+
"Attention module is in charge of linking the question with the recipe text and the entities present in the recipe. It takes the matrices $\\mathbf {Q^{\\prime }}$ and $\\mathbf {R}^{\\prime }$ from the input module, and $\\mathbf {E}$ from the reasoning module and constructs the question-aware recipe representation $\\mathbf {G}$ and the question-aware entity representation $\\mathbf {Y}$. Following the attention flow mechanism described in BIBREF14, we specifically calculate attentions in four different directions: (1) from question to recipe, (2) from recipe to question, (3) from question to entities, and (4) from entities to question.",
|
| 62 |
+
"The first two of these attentions require computing a shared affinity matrix $\\mathbf {S}^R \\in \\mathbb {R}^{N \\times M}$ with $\\mathbf {S}^R_{i,j}$ indicating the similarity between $i$-th recipe word and $j$-th image in the question estimated by",
|
| 63 |
+
"where $\\mathbf {w}^{\\top }_{R}$ is a trainable weight vector, $\\circ $ and $[;]$ denote elementwise multiplication and concatenation operations, respectively.",
|
| 64 |
+
"Recipe-to-question attention determines the images within the question that is most relevant to each word of the recipe. Let $\\mathbf {\\tilde{Q}} \\in \\mathbb {R}^{2d \\times N}$ represent the recipe-to-question attention matrix with its $i$-th column being given by $ \\mathbf {\\tilde{Q}}_i=\\sum _j \\mathbf {a}_{ij}\\mathbf {Q}^{\\prime }_j$ where the attention weight is computed by $\\mathbf {a}_i=\\operatorname{softmax}(\\mathbf {S}^R_{i}) \\in \\mathbb {R}^M$.",
|
| 65 |
+
"Question-to-recipe attention signifies the words within the recipe that have the closest similarity to each image in the question, and construct an attended recipe vector given by $ \\tilde{\\mathbf {r}}=\\sum _{i}\\mathbf {b}_i\\mathbf {R}^{\\prime }_i$ with the attention weight is calculated by $\\mathbf {b}=\\operatorname{softmax}(\\operatorname{max}_{\\mathit {col}}(\\mathbf {S}^R)) \\in \\mathbb {R}^{N}$ where $\\operatorname{max}_{\\mathit {col}}$ denotes the maximum function across the column. The question-to-recipe matrix is then obtained by replicating $\\tilde{\\mathbf {r}}$ $N$ times across the column, giving $\\tilde{\\mathbf {R}} \\in \\mathbb {R}^{2d \\times N}$.",
|
| 66 |
+
"Then, we construct the question aware representation of the input recipe, $\\mathbf {G}$, with its $i$-th column $\\mathbf {G}_i \\in \\mathbb {R}^{8d \\times N}$ denoting the final embedding of $i$-th word given by",
|
| 67 |
+
"Attentions from question to entities, and from entities to question are computed in a way similar to the ones described above. The only difference is that it uses a different shared affinity matrix to be computed between the memory encoding entities $\\mathbf {E}$ and the question $\\mathbf {Q}^{\\prime }$. These attentions are then used to construct the question aware representation of entities, denoted by $\\mathbf {Y}$, that links and integrates the images in the question and the entities in the input recipe."
|
| 68 |
+
],
|
| 69 |
+
[
|
| 70 |
+
"Modeling module takes the question-aware representations of the recipe $\\mathbf {G}$ and the entities $\\mathbf {Y}$, and forms their combined vector representation. For this purpose, we first use a two-layer BiLSTM to read the question-aware recipe $\\mathbf {G}$ and to encode the interactions among the words conditioned on the question. For each direction of BiLSTM , we use its hidden state after reading the last token as its output. In the end, we obtain a vector embedding $\\mathbf {c} \\in \\mathbb {R}^{2d \\times 1}$. Similarly, we employ a second BiLSTM, this time, over the entities $\\mathbf {Y}$, which results in another vector embedding $\\mathbf {f} \\in \\mathbb {R}^{2d_E \\times 1}$. Finally, these vector representations are concatenated and then projected to a fixed size representation using $\\mathbf {o}=\\varphi _o(\\left[\\mathbf {c}; \\mathbf {f}\\right]) \\in \\mathbb {R}^{2d \\times 1}$ where $\\varphi _o$ is a multilayer perceptron with $\\operatorname{tanh}$ activation function."
|
| 71 |
+
],
|
| 72 |
+
[
|
| 73 |
+
"The output module takes the output of the modeling module, encoding vector embeddings of the question-aware recipe and the entities $\\mathbf {Y}$, and the embedding of the answer $\\mathbf {A}$, and returns a similarity score which is used while determining the correct answer. Among all the candidate answer, the one having the highest similarity score is chosen as the correct answer. To train our proposed procedural reasoning network, we employ a hinge ranking loss BIBREF15, similar to the one used in BIBREF2, given below.",
|
| 74 |
+
"where $\\gamma $ is the margin parameter, $\\mathbf {a}_+$ and $\\mathbf {a}_{-}$ are the correct and the incorrect answers, respectively."
|
| 75 |
+
],
|
| 76 |
+
[
|
| 77 |
+
"In this section, we describe our experimental setup and then analyze the results of the proposed Procedural Reasoning Networks (PRN) model."
|
| 78 |
+
],
|
| 79 |
+
[
|
| 80 |
+
"Given a recipe, we automatically extract the entities from the initial step of a recipe by using a dictionary of ingredients. While determining the ingredients, we exploit Recipe1M BIBREF16 and Kaggle What\u2019s Cooking Recipes BIBREF17 datasets, and form our dictionary using the most commonly used ingredients in the training set of RecipeQA. For the cases when no entity can be extracted from the recipe automatically (20 recipes in total), we manually annotate those recipes with the related entities."
|
| 81 |
+
],
|
| 82 |
+
[
|
| 83 |
+
"In our experiments, we separately trained models on each task, as well as we investigated multi-task learning where a single model is trained to solve all these tasks at once. In total, the PRN architecture consists of $\\sim $12M trainable parameters. We implemented our models in PyTorch BIBREF18 using AllenNLP library BIBREF6. We used Adam optimizer with a learning rate of 1e-4 with an early stopping criteria with the patience set to 10 indicating that the training procedure ends after 10 iterations if the performance would not improve. We considered a batch size of 32 due to our hardware constraints. In the multi-task setting, batches are sampled round-robin from all tasks, where each batch is solely composed of examples from one task. We performed our experiments on a system containing four NVIDIA GTX-1080Ti GPUs, and training a single model took around 2 hours. We employed the same hyperparameters for all the baseline systems. We plan to share our code and model implementation after the review process."
|
| 84 |
+
],
|
| 85 |
+
[
|
| 86 |
+
"We compare our model with several baseline models as described below. We note that the results of the first two are previously reported in BIBREF2.",
|
| 87 |
+
"Hasty Student BIBREF2 is a heuristics-based simple model which ignores the recipe and gives an answer by examining only the question and the answer set using distances in the visual feature space.",
|
| 88 |
+
"Impatient Reader BIBREF19 is a simple neural model that takes its name from the fact that it repeatedly computes attention over the recipe after observing each image in the query.",
|
| 89 |
+
"BiDAF BIBREF14 is a strong reading comprehension model that employs a bi-directional attention flow mechanism to obtain a question-aware representation and bases its predictions on this representation. Originally, it is a span-selection model from the input context. Here, we adapt it to work in a multimodal setting and answer multiple choice questions instead.",
|
| 90 |
+
"BiDAF w/ static memory is an extended version of the BiDAF model which resembles our proposed PRN model in that it includes a memory unit for the entities. However, it does not make any updates on the memory cells. That is, it uses the static entity embeeddings initialized with GloVe word vectors. We propose this baseline to test the significance of the use of relational memory updates."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"Table TABREF29 presents the quantitative results for the visual reasoning tasks in RecipeQA. In single-task training setting, PRN gives state-of-the-art results compared to other neural models. Moreover, it achieves the best performance on average. These results demonstrate the importance of having a dynamic memory and keeping track of entities extracted from the recipe. In multi-task training setting where a single model is trained to solve all the tasks at once, PRN and BIDAF w/ static memory perform comparably and give much better results than BIDAF. Note that the model performances in the multi-task training setting are worse than single-task performances. We believe that this is due to the nature of the tasks that some are more difficult than the others. We think that the performance could be improved by employing a carefully selected curriculum strategy BIBREF20.",
|
| 94 |
+
"In Fig. FIGREF28, we illustrate the entity embeddings space by projecting the learned embeddings from the step-by-step memory snapshots through time with t-SNE to 3-d space from 200-d vector space. Color codes denote the categories of the cooking recipes. As can be seen, these step-aware embeddings show clear clustering of these categories. Moreover, within each cluster, the entities are grouped together in terms of their state characteristics. For instance, in the zoomed parts of the figure, chopped and sliced, or stirred and whisked entities are placed close to each other.",
|
| 95 |
+
"Fig. FIGREF30 demonstrates the entity arithmetics using the learned embeddings from each entity step. Here, we show that the learned embedding from the memory snapshots can effectively capture the contextual information about the entities at each time point in the corresponding step while taking into account of the recipe data. This basic arithmetic operation suggests that the proposed model can successfully capture the semantics of each entity's state in the corresponding step."
|
| 96 |
+
],
|
| 97 |
+
[
|
| 98 |
+
"In recent years, tracking entities and their state changes have been explored in the literature from a variety of perspectives. In an early work, BIBREF21 proposed a dynamic memory based network which updates entity states using a gating mechanism while reading the text. BIBREF22 presented a more structured memory augmented model which employs memory slots for representing both entities and their relations. BIBREF23 suggested a conceptually similar model in which the pairwise relations between attended memories are utilized to encode the world state. The main difference between our approach and these works is that by utilizing relational memory core units we also allow memories to interact with each other during each update.",
|
| 99 |
+
"BIBREF24 showed that similar ideas can be used to compile supporting memories in tracking dialogue state. BIBREF25 has shown the importance of coreference signals for reading comprehension task. More recently, BIBREF26 introduced a specialized recurrent layer which uses coreference annotations for improving reading comprehension tasks. On language modeling task, BIBREF27 proposed a language model which can explicitly incorporate entities while dynamically updating their representations for a variety of tasks such as language modeling, coreference resolution, and entity prediction.",
|
| 100 |
+
"Our work builds upon and contributes to the growing literature on tracking states changes in procedural text. BIBREF0 presented a neural model that can learn to explicitly predict state changes of ingredients at different points in a cooking recipe. BIBREF1 proposed another entity-aware model to track entity states in scientific processes. BIBREF3 demonstrated that the prediction quality can be boosted by including hard and soft constraints to eliminate unlikely or favor probable state changes. In a follow-up work, BIBREF4 exploited the notion of label consistency in training to enforce similar predictions in similar procedural contexts. BIBREF28 proposed a model that dynamically constructs a knowledge graph while reading the procedural text to track the ever-changing entities states. As discussed in the introduction, however, these previous methods use a strong inductive bias and assume that state labels are present during training. In our study, we deliberately focus on unlabeled procedural data and ask the question: Can multimodality help to identify and provide insights to understanding state changes."
|
| 101 |
+
],
|
| 102 |
+
[
|
| 103 |
+
"We have presented a new neural architecture called Procedural Reasoning Networks (PRN) for multimodal understanding of step-by-step instructions. Our proposed model is based on the successful BiDAF framework but also equipped with an explicit memory unit that provides an implicit mechanism to keep track of the changes in the states of the entities over the course of the procedure. Our experimental analysis on visual reasoning tasks in the RecipeQA dataset shows that the model significantly improves the results of the previous models, indicating that it better understands the procedural text and the accompanying images. Additionally, we carefully analyze our results and find that our approach learns meaningful dynamic representations of entities without any entity-level supervision. Although we achieve state-of-the-art results on RecipeQA, clearly there is still room for improvement compared to human performance. We also believe that the PRN architecture will be of value to other visual and textual sequential reasoning tasks."
|
| 104 |
+
],
|
| 105 |
+
[
|
| 106 |
+
"We thank the anonymous reviewers and area chairs for their invaluable feedback. This work was supported by TUBA GEBIP fellowship awarded to E. Erdem; and by the MMVC project via an Institutional Links grant (Project No. 217E054) under the Newton-Katip \u00c7elebi Fund partnership funded by the Scientific and Technological Research Council of Turkey (TUBITAK) and the British Council. We also thank NVIDIA Corporation for the donation of GPUs used in this research."
|
| 107 |
+
]
|
| 108 |
+
]
|
| 109 |
+
}
|
| 110 |
+
```
|
qasper-0141/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: Active Learning for Chinese Word Segmentation in Medical Text
|
| 2 |
+
|
| 3 |
+
Question: How does the scoring model work?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Chinese Word Segmentation",
|
| 12 |
+
"Active Learning",
|
| 13 |
+
"Active Learning for Chinese Word Segmentation",
|
| 14 |
+
"CRF-based Word Segmenter",
|
| 15 |
+
"Information Entropy Based Scoring Model",
|
| 16 |
+
"Datasets",
|
| 17 |
+
"Parameter Settings",
|
| 18 |
+
"Experimental Results",
|
| 19 |
+
"Conclusion and Future Work",
|
| 20 |
+
"Acknowledgment"
|
| 21 |
+
],
|
| 22 |
+
"paragraphs": [
|
| 23 |
+
[
|
| 24 |
+
"Electronic health records (EHRs) systematically collect patients' clinical information, such as health profiles, histories of present illness, past medical histories, examination results and treatment plans BIBREF0 . By analyzing EHRs, many useful information, closely related to patients, can be discovered BIBREF1 . Since Chinese EHRs are recorded without explicit word delimiters (e.g., \u201cUTF8gkai\u7cd6\u5c3f\u75c5\u916e\u75c7\u9178\u4e2d\u6bd2\u201d (diabetic ketoacidosis)), Chinese word segmentation (CWS) is a prerequisite for processing EHRs. Currently, state-of-the-art CWS methods usually require large amounts of manually-labeled data to reach their full potential. However, there are many challenges inherent in labeling EHRs. First, EHRs have many medical terminologies, such as \u201cUTF8gkai\u9ad8\u8840\u538b\u6027\u5fc3\u810f\u75c5\u201d (hypertensive heart disease) and \u201cUTF8gkai\u7f57\u6c0f\u82ac\u201d (Rocephin), so only annotators with medical backgrounds can be qualified to label EHRs. Second, EHRs may involve personal privacies of patients. Therefore, they cannot be openly published on a large scale for labeling. The above two problems lead to the high annotation cost and insufficient training corpus in the research of CWS in medical text.",
|
| 25 |
+
"CWS was usually formulated as a sequence labeling task BIBREF2 , which can be solved by supervised learning approaches, such as hidden markov model (HMM) BIBREF3 and conditional random field (CRF) BIBREF4 . However, these methods rely heavily on handcrafted features. To relieve the efforts of feature engineering, neural network-based methods are beginning to thrive BIBREF5 , BIBREF6 , BIBREF7 . However, due to insufficient annotated training data, conventional models for CWS trained on open corpus often suffer from significant performance degradation when transferred to a domain-specific text. Moreover, the task in medical domain is rarely dabbled, and only one related work on transfer learning is found in recent literatures BIBREF8 . However, researches related to transfer learning mostly remain in general domains, causing a major problem that a considerable amount of manually annotated data is required, when introducing the models into specific domains.",
|
| 26 |
+
"One of the solutions for this obstacle is to use active learning, where only a small scale of samples are selected and labeled in an active manner. Active learning methods are favored by the researchers in many natural language processing (NLP) tasks, such as text classification BIBREF9 and named entity recognition (NER) BIBREF10 . However, only a handful of works are conducted on CWS BIBREF2 , and few focuses on medical domain tasks.",
|
| 27 |
+
"Given the aforementioned challenges and current researches, we propose a word segmentation method based on active learning. To model the segmentation history, we incorporate a sampling strategy consisting of word score, link score and sequence score, which effectively evaluates the segmentation decisions. Specifically, we combine information branch and gated neural network to determine if the segment is a legal word, i.e., word score. Meanwhile, we use the hidden layer output of the long short-term memory (LSTM) BIBREF11 to find out how the word is linked to its surroundings, i.e., link score. The final decision on the selection of labeling samples is made by calculating the average of word and link scores on the whole segmented sentence, i.e., sequence score. Besides, to capture coherence over characters, we additionally add K-means clustering features to the input of CRF-based word segmenter.",
|
| 28 |
+
"To sum up, the main contributions of our work are summarized as follows:",
|
| 29 |
+
"The rest of this paper is organized as follows. Section SECREF2 briefly reviews the related work on CWS and active learning. Section SECREF3 presents an active learning method for CWS. We experimentally evaluate our proposed method in Section SECREF4 . Finally, Section SECREF5 concludes the paper and envisions on future work."
|
| 30 |
+
],
|
| 31 |
+
[
|
| 32 |
+
"In past decades, researches on CWS have a long history and various methods have been proposed BIBREF13 , BIBREF14 , BIBREF15 , which is an important task for Chinese NLP BIBREF7 . These methods are mainly focus on two categories: supervised learning and deep learning BIBREF2 .",
|
| 33 |
+
"Supervised Learning Methods. Initially, supervised learning methods were widely-used in CWS. Xue BIBREF13 employed a maximum entropy tagger to automatically assign Chinese characters. Zhao et al. BIBREF16 used a conditional random field for tag decoding and considered both feature template selection and tag set selection. However, these methods greatly rely on manual feature engineering BIBREF17 , while handcrafted features are difficult to design, and the size of these features is usually very large BIBREF6 .",
|
| 34 |
+
"Deep Learning Methods. Recently, neural networks have been applied in CWS tasks. To name a few, Zheng et al. BIBREF14 used deep layers of neural networks to learn feature representations of characters. Chen et al. BIBREF6 adopted LSTM to capture the previous important information. Chen et al. BIBREF18 proposed a gated recursive neural network (GRNN), which contains reset and update gates to incorporate the complicated combinations of characters. Jiang and Tang BIBREF19 proposed a sequence-to-sequence transformer model to avoid overfitting and capture character information at the distant site of a sentence. Yang et al. BIBREF20 investigated subword information for CWS and integrated subword embeddings into a Lattice LSTM (LaLSTM) network. However, general word segmentation models do not work well in specific field due to lack of annotated training data.",
|
| 35 |
+
"Currently, a handful of domain-specific CWS approaches have been studied, but they focused on decentralized domains. In the metallurgical field, Shao et al. BIBREF15 proposed a domain-specific CWS method based on Bi-LSTM model. In the medical field, Xing et al. BIBREF8 proposed an adaptive multi-task transfer learning framework to fully leverage domain-invariant knowledge from high resource domain to medical domain. Meanwhile, transfer learning still greatly focuses on the corpus in general domain. When it comes to the specific domain, large amounts of manually-annotated data is necessary. Active learning can solve this problem to a certain extent. However, due to the challenges faced by performing active learning on CWS, only a few studies have been conducted. On judgements, Yan et al. BIBREF21 adopted the local annotation strategy, which selects substrings around the informative characters in active learning. However, their method still stays at the statistical level. Unlike the above method, we propose an active learning approach for CWS in medical text, which combines information entropy with neural network to effectively reduce annotation cost."
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"Active learning BIBREF22 mainly aims to ease the data collection process by automatically deciding which instances should be labeled by annotators to train a model as quickly and effectively as possible BIBREF23 . The sampling strategy plays a key role in active learning. In the past decade, the rapid development of active learning has resulted in various sampling strategies, such as uncertainty sampling BIBREF24 , query-by-committee BIBREF25 and information gain BIBREF26 . Currently, the most mainstream sampling strategy is uncertainty sampling. It focuses its selection on samples closest to the decision boundary of the classifier and then chooses these samples for annotators to relabel BIBREF27 .",
|
| 39 |
+
"The formal definition of uncertainty sampling is to select a sample INLINEFORM0 that maximizes the entropy INLINEFORM1 over the probability of predicted classes: DISPLAYFORM0 ",
|
| 40 |
+
"where INLINEFORM0 is a multi-dimensional feature vector, INLINEFORM1 is its binary label, and INLINEFORM2 is the predicted probability, through which a classifier trained on training sets can map features to labels. However, in some complicated tasks, such as CWS and NER, only considering the uncertainty of classifier is obviously not enough."
|
| 41 |
+
],
|
| 42 |
+
[
|
| 43 |
+
"Active learning methods can generally be described into two parts: a learning engine and a selection engine BIBREF28 . The learning engine is essentially a classifier, which is mainly used for training of classification problems. The selection engine is based on the sampling strategy, which chooses samples that need to be relabeled by annotators from unlabeled data. Then, relabeled samples are added to training set for classifier to re-train, thus continuously improving the accuracy of the classifier. In this paper, a CRF-based segmenter and a scoring model are employed as learning engine and selection engine, respectively.",
|
| 44 |
+
"Fig. FIGREF7 and Algorithm SECREF3 demonstrate the procedure of CWS based on active learning. First, we train a CRF-based segmenter by train set. Then, the segmenter is employed to annotate the unlabeled set roughly. Subsequently, information entropy based scoring model picks INLINEFORM0 -lowest ranking samples for annotators to relabel. Meanwhile, the train sets and unlabeled sets are updated. Finally, we re-train the segmenter. The above steps iterate until the desired accuracy is achieved or the number of iterations has reached a predefined threshold. [!ht] Active Learning for Chinese Word Segmentation labeled data INLINEFORM1 , unlabeled data INLINEFORM2 , the number of iterations INLINEFORM3 , the number of samples selected per iteration INLINEFORM4 , partitioning function INLINEFORM5 , size INLINEFORM6 a word segmentation model INLINEFORM7 with the smallest test set loss INLINEFORM8 Initialize: INLINEFORM9 ",
|
| 45 |
+
" train a word segmenter INLINEFORM0 ",
|
| 46 |
+
" estimate the test set loss INLINEFORM0 ",
|
| 47 |
+
" label INLINEFORM0 by INLINEFORM1 ",
|
| 48 |
+
" INLINEFORM0 to INLINEFORM1 INLINEFORM2 compute INLINEFORM3 by branch information entropy based scoring model",
|
| 49 |
+
" select INLINEFORM0 -lowest ranking samples INLINEFORM1 ",
|
| 50 |
+
"relabel INLINEFORM0 by annotators",
|
| 51 |
+
"form a new labeled dataset INLINEFORM0 ",
|
| 52 |
+
"form a new unlabeled dataset INLINEFORM0 ",
|
| 53 |
+
"train a word segmenter INLINEFORM0 ",
|
| 54 |
+
"estimate the new test loss INLINEFORM0 ",
|
| 55 |
+
"compute the loss reduction INLINEFORM0 ",
|
| 56 |
+
" INLINEFORM0 INLINEFORM1 ",
|
| 57 |
+
" INLINEFORM0 ",
|
| 58 |
+
" INLINEFORM0 INLINEFORM1 with the smallest test set loss INLINEFORM2 INLINEFORM3 "
|
| 59 |
+
],
|
| 60 |
+
[
|
| 61 |
+
"CWS can be formalized as a sequence labeling problem with character position tags, which are (`B', `M', `E', `S'). So, we convert the labeled data into the `BMES' format, in which each character in the sequence is assigned into a label as follows one by one: B=beginning of a word, M=middle of a word, E=end of a word and S=single word.",
|
| 62 |
+
"In this paper, we use CRF as a training model for CWS task. Given the observed sequence, CRF has a single exponential model for the joint probability of the entire sequence of labels, while maximum entropy markov model (MEMM) BIBREF29 uses per-state exponential models for the conditional probabilities of next states BIBREF4 . Therefore, it can solve the label bias problem effectively. Compared with neural networks, it has less dependency on the corpus size.",
|
| 63 |
+
"First, we pre-process EHRs at the character-level, separating each character of raw EHRs. For instance, given a sentence INLINEFORM0 , where INLINEFORM1 represents the INLINEFORM2 -th character, the separated form is INLINEFORM3 . Then, we employ Word2Vec BIBREF30 to train pre-processed EHRs to get character embeddings. To capture interactions between adjacent characters, K-means clustering algorithm BIBREF31 is utilized to feature the coherence over characters. In general, K-means divides INLINEFORM4 EHR characters into INLINEFORM5 groups of clusters and the similarity of EHR characters in the same cluster is higher. With each iteration, K-means can classify EHR characters into the nearest cluster based on distance to the mean vector. Then, recalculating and adjusting the mean vectors of these clusters until the mean vector converges. K-means features explicitly show the difference between two adjacent characters and even multiple characters. Finally, we additionally add K-means clustering features to the input of CRF-based segmenter. The segmenter makes positional tagging decisions over individual characters. For example, a Chinese segmented sentence UTF8gkai\u201c\u75c5\u4eba/\u957f\u671f/\u4e8e/\u6211\u9662/\u80be\u75c5\u79d1/\u4f4f\u9662/\u6cbb\u7597/\u3002/\" (The patient was hospitalized for a long time in the nephrology department of our hospital.) is labeled as `BEBESBEBMEBEBES'."
|
| 64 |
+
],
|
| 65 |
+
[
|
| 66 |
+
"To select the most appropriate sentences in a large number of unlabeled corpora, we propose a scoring model based on information entropy and neural network as the sampling strategy of active learning, which is inspired by Cai and Zhao BIBREF32 . The score of a segmented sentence is computed as follows. First, mapping the segmented sentence to a sequence of candidate word embeddings. Then, the scoring model takes the word embedding sequence as input, scoring over each individual candidate word from two perspectives: (1) the possibility that the candidate word itself can be regarded as a legal word; (2) the rationality of the link that the candidate word directly follows previous segmentation history. Fig. FIGREF10 illustrates the entire scoring model. A gated neural network is employed over character embeddings to generate distributed representations of candidate words, which are sent to a LSTM model.",
|
| 67 |
+
"We use gated neural network and information entropy to capture the likelihood of the segment being a legal word. The architecture of word score model is depicted in Fig. FIGREF12 .",
|
| 68 |
+
"Gated Combination Neural Network (GCNN)",
|
| 69 |
+
"To effectively learn word representations through character embeddings, we use GCNN BIBREF32 . The architecture of GCNN is demonstrated in Fig. FIGREF13 , which includes update gate and reset gate. The gated mechanism not only captures the characteristics of the characters themselves, but also utilizes the interaction between the characters. There are two types of gates in this network structure: reset gates and update gates. These two gated vectors determine the final output of the gated recurrent neural network, where the update gate helps the model determine what to be passed, and the reset gate primarily helps the model decide what to be cleared. In particular, the word embedding of a word with INLINEFORM0 characters can be computed as: DISPLAYFORM0 ",
|
| 70 |
+
"where INLINEFORM0 and INLINEFORM1 are update gates for new combination vector INLINEFORM2 and the i-th character INLINEFORM3 respectively, the combination vector INLINEFORM4 is formalized as: DISPLAYFORM0 ",
|
| 71 |
+
"where INLINEFORM0 and INLINEFORM1 are reset gates for characters.",
|
| 72 |
+
"Left and Right Branch Information Entropy In general, each string in a sentence may be a word. However, compared with a string which is not a word, the string of a word is significantly more independent. The branch information entropy is usually used to judge whether each character in a string is tightly linked through the statistical characteristics of the string, which reflects the likelihood of a string being a word. The left and right branch information entropy can be formalized as follows: DISPLAYFORM0 DISPLAYFORM1 ",
|
| 73 |
+
"where INLINEFORM0 denotes the INLINEFORM1 -th candidate word, INLINEFORM2 denotes the character set, INLINEFORM3 denotes the probability that character INLINEFORM4 is on the left of word INLINEFORM5 and INLINEFORM6 denotes the probability that character INLINEFORM7 is on the right of word INLINEFORM8 . INLINEFORM9 and INLINEFORM10 respectively represent the left and right branch information entropy of the candidate word INLINEFORM11 . If the left and right branch information entropy of a candidate word is relatively high, the probability that the candidate word can be combined with the surrounded characters to form a word is low, thus the candidate word is likely to be a legal word.",
|
| 74 |
+
"To judge whether the candidate words in a segmented sentence are legal words, we compute the left and right entropy of each candidate word, then take average as the measurement standard: DISPLAYFORM0 ",
|
| 75 |
+
"We represent a segmented sentence with INLINEFORM0 candidate words as [ INLINEFORM1 , INLINEFORM2 ,..., INLINEFORM3 ], so the INLINEFORM4 ( INLINEFORM5 ) of the INLINEFORM6 -th candidate word is computed by its average entropy: DISPLAYFORM0 ",
|
| 76 |
+
"In this paper, we use LSTM to capture the coherence between words in a segmented sentence. This neural network is mainly an optimization for traditional RNN. RNN is widely used to deal with time-series prediction problems. The result of its current hidden layer is determined by the input of the current layer and the output of the previous hidden layer BIBREF33 . Therefore, RNN can remember historical results. However, traditional RNN has problems of vanishing gradient and exploding gradient when training long sequences BIBREF34 . By adding a gated mechanism to RNN, LSTM effectively solves these problems, which motivates us to get the link score with LSTM. Formally, the LSTM unit performs the following operations at time step INLINEFORM0 : DISPLAYFORM0 DISPLAYFORM1 ",
|
| 77 |
+
"where INLINEFORM0 , INLINEFORM1 , INLINEFORM2 are the inputs of LSTM, all INLINEFORM3 and INLINEFORM4 are a set of parameter matrices to be trained, and INLINEFORM5 is a set of bias parameter matrices to be trained. INLINEFORM6 and INLINEFORM7 operation respectively represent matrix element-wise multiplication and sigmoid function. In the LSTM unit, there are two hidden layers ( INLINEFORM8 , INLINEFORM9 ), where INLINEFORM10 is the internal memory cell for dealing with vanishing gradient, while INLINEFORM11 is the main output of the LSTM unit for complex operations in subsequent layers.",
|
| 78 |
+
"We denotes INLINEFORM0 as the word embedding of time step INLINEFORM1 , a prediction INLINEFORM2 of next word embedding INLINEFORM3 can be computed by hidden layer INLINEFORM4 : DISPLAYFORM0 ",
|
| 79 |
+
"Therefore, link score of next word embedding INLINEFORM0 can be computed as: DISPLAYFORM0 ",
|
| 80 |
+
"Due to the structure of LSTM, vector INLINEFORM0 contains important information of entire segmentation decisions. In this way, the link score gets the result of the sequence-level word segmentation, not just word-level.",
|
| 81 |
+
"Intuitively, we can compute the score of a segmented sequence by summing up word scores and link scores. However, we find that a sequence with more candidate words tends to have higher sequence scores. Therefore, to alleviate the impact of the number of candidate words on sequence scores, we calculate final scores as follows: DISPLAYFORM0 ",
|
| 82 |
+
"where INLINEFORM0 denotes the INLINEFORM1 -th segmented sequence with INLINEFORM2 candidate words, and INLINEFORM3 represents the INLINEFORM4 -th candidate words in the segmented sequence.",
|
| 83 |
+
"When training the model, we seek to minimize the sequence score of the corrected segmented sentence and the predicted segmented sentence. DISPLAYFORM0 ",
|
| 84 |
+
"where INLINEFORM0 is the loss function."
|
| 85 |
+
],
|
| 86 |
+
[
|
| 87 |
+
"We collect 204 EHRs with cardiovascular diseases from the Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine and each contains 27 types of records. We choose 4 different types with a total of 3868 records from them, which are first course reports, medical records, chief ward round records and discharge records. The detailed information of EHRs are listed in Table TABREF32 .",
|
| 88 |
+
"We split our datasets as follows. First, we randomly select 3200 records from 3868 records as unlabeled set. Then, we manually annotate remaining 668 records as labeled set, which contains 1170 sentences. Finally, we divide labeled set into train set and test set with the ratio of 7:3 randomly. Statistics of datasets are listed in Table TABREF33 ."
|
| 89 |
+
],
|
| 90 |
+
[
|
| 91 |
+
"To determine suitable parameters, we divide training set into two sets, the first 80% sentences as training set and the rest 20% sentences as validation set.",
|
| 92 |
+
"Character embedding dimensions and K-means clusters are two main parameters in the CRF-based word segmenter.",
|
| 93 |
+
"In this paper, we choose character-based CRF without any features as baseline. First, we use Word2Vec to train character embeddings with dimensions of [`50', `100', `150', `200', `300', `400'] respectively, thus we obtain 6 different dimensional character embeddings. Second, these six types of character embeddings are used as the input to K-means algorithm with the number of clusters [`50', `100', `200', `300', `400', `500', `600'] respectively to capture the corresponding features of character embeddings. Then, we add K-means clustering features to baseline for training. As can be seen from Fig. FIGREF36 , when the character embedding dimension INLINEFORM0 = 150 and the number of clusters INLINEFORM1 = 400, CRF-based word segmenter performs best, so these two parameters are used in subsequent experiments.",
|
| 94 |
+
"Hyper-parameters of neural network have a great impact on the performance. The hyper-parameters we choose are listed in Table TABREF38 .",
|
| 95 |
+
"The dimension of character embeddings is set as same as the parameter used in CRF-based word segmenter and the number of hidden units is also set to be the same as it. Maximum word length is ralated to the number of parameters in GCNN unit. Since there are many long medical terminologies in EHRs, we set the maximum word length as 6. In addition, dropout is an effective way to prevent neural networks from overfitting BIBREF35 . To avoid overfitting, we drop the input layer of the scoring model with the rate of 20%."
|
| 96 |
+
],
|
| 97 |
+
[
|
| 98 |
+
"Our work experimentally compares two mainstream CWS tools (LTP and Jieba) on training and testing sets. These two tools are widely used and recognized due to their high INLINEFORM0 -score of word segmentation in general fields. However, in specific fields, there are many terminologies and uncommon words, which lead to the unsatisfactory performance of segmentation results. To solve the problem of word segmentation in specific fields, these two tools provide a custom dictionary for users. In the experiments, we also conduct a comparative experiment on whether external domain dictionary has an effect on the experimental results. We manually construct the dictionary when labeling EHRs.",
|
| 99 |
+
"From the results in Table TABREF41 , we find that Jieba benefits a lot from the external dictionary. However, the Recall of LTP decreases when joining the domain dictionary. Generally speaking, since these two tools are trained by general domain corpus, the results are not ideal enough to cater to the needs of subsequent NLP of EHRs when applied to specific fields.",
|
| 100 |
+
"To investigate the effectiveness of K-means features in CRF-based segmenter, we also compare K-means with 3 different clustering features, including MeanShift BIBREF36 , SpectralClustering BIBREF37 and DBSCAN BIBREF38 on training and testing sets. From the results in Table TABREF43 , by adding additional clustering features in CRF-based segmenter, there is a significant improvement of INLINEFORM0 -score, which indicates that clustering features can effectively capture the semantic coherence between characters. Among these clustering features, K-means performs best, so we utlize K-means results as additional features for CRF-based segmenter.",
|
| 101 |
+
"In this experiment, since uncertainty sampling is the most popular strategy in real applications for its simpleness and effectiveness BIBREF27 , we compare our proposed strategy with uncertainty sampling in active learning. We conduct our experiments as follows. First, we employ CRF-based segmenter to annotate the unlabeled set. Then, sampling strategy in active learning selects a part of samples for annotators to relabel. Finally, the relabeled samples are added to train set for segmenter to re-train. Our proposed scoring strategy selects samples according to the sequence scores of the segmented sentences, while uncertainty sampling suggests relabeling samples that are closest to the segmenter\u2019s decision boundary.",
|
| 102 |
+
"Generally, two main parameters in active learning are the numbers of iterations and samples selected per iteration. To fairly investigate the influence of two parameters, we compare our proposed strategy with uncertainty sampling on the same parameter. We find that though the number of iterations is large enough, it has a limited impact on the performance of segmenter. Therefore, we choose 30 as the number of iterations, which is a good trade-off between speed and performance. As for the number of samples selected per iteration, there are 6078 sentences in unlabeled set, considering the high cost of relabeling, we set four sizes of samples selected per iteration, which are 2%, 5%, 8% and 11%.",
|
| 103 |
+
"The experimental results of two sampling strategies with 30 iterations on four different proportions of relabeled data are shown in Fig. FIGREF45 , where x-axis represents the number of iterations and y-axis denotes the INLINEFORM0 -score of the segmenter. Scoring strategy shows consistent improvements over uncertainty sampling in the early iterations, indicating that scoring strategy is more capable of selecting representative samples.",
|
| 104 |
+
"Furthermore, we also investigate the relations between the best INLINEFORM0 -score and corresponding number of iteration on two sampling strategies, which is depicted in Fig. FIGREF46 .",
|
| 105 |
+
"It is observed that in our proposed scoring model, with the proportion of relabeled data increasing, the iteration number of reaching the optimal word segmentation result is decreasing, but the INLINEFORM0 -score of CRF-based word segmenter is also gradually decreasing. When the proportion is 2%, the segmenter reaches the highest INLINEFORM1 -score: 90.62%. Obviously, our proposed strategy outperforms uncertainty sampling by a large margin. Our proposed method needs only 2% relabeled samples to obtain INLINEFORM2 -score of 90.62%, while uncertainty sampling requires 8% samples to reach its best INLINEFORM3 -score of 88.98%, which indicates that with our proposed method, we only need to manually relabel a small number of samples to achieve a desired segmentation result."
|
| 106 |
+
],
|
| 107 |
+
[
|
| 108 |
+
"To relieve the efforts of EHRs annotation, we propose an effective word segmentation method based on active learning, in which the sampling strategy is a scoring model combining information entropy with neural network. Compared with the mainstream uncertainty sampling, our strategy selects samples from statistical perspective and deep learning level. In addition, to capture coherence between characters, we add K-means clustering features to CRF-based word segmenter. Based on EHRs collected from the Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, we evaluate our method on CWS task. Compared with uncertainty sampling, our method requires 6% less relabeled samples to achieve better performance, which proves that our method can save the cost of manual annotation to a certain extent.",
|
| 109 |
+
"In future, we plan to employ other widely-used deep neural networks, such as convolutional neural network and attention mechanism, in the research of EHRs segmentation. Then, we believe that our method can be applied to other tasks as well, so we will fully investigate the application of our method in other tasks, such as NER and relation extraction."
|
| 110 |
+
],
|
| 111 |
+
[
|
| 112 |
+
"The authors would like to appreciate any suggestions or comments from the anonymous reviewers. This work was supported by the National Natural Science Foundation of China (No. 61772201) and the National Key R&D Program of China for \u201cPrecision medical research\" (No. 2018YFC0910550)."
|
| 113 |
+
]
|
| 114 |
+
]
|
| 115 |
+
}
|
| 116 |
+
```
|
qasper-0146/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: InScript: Narrative texts annotated with script information
|
| 2 |
+
|
| 3 |
+
Question: How many subjects have been used to create the annotations?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Motivation",
|
| 11 |
+
"Collection via Amazon M-Turk",
|
| 12 |
+
"Data Statistics",
|
| 13 |
+
"Annotation",
|
| 14 |
+
"Annotation Schema",
|
| 15 |
+
"Development of the Schema",
|
| 16 |
+
"First Annotation Phase",
|
| 17 |
+
"Modification of the Schema",
|
| 18 |
+
"Special Cases",
|
| 19 |
+
"Inter-Annotator Agreement",
|
| 20 |
+
"Annotated Corpus Statistics",
|
| 21 |
+
"Comparison to the DeScript Corpus",
|
| 22 |
+
"Conclusion",
|
| 23 |
+
"Acknowledgements"
|
| 24 |
+
],
|
| 25 |
+
"paragraphs": [
|
| 26 |
+
[
|
| 27 |
+
"A script is \u201ca standardized sequence of events that describes some stereotypical human activity such as going to a restaurant or visiting a doctor\u201d BIBREF0 . Script events describe an action/activity along with the involved participants. For example, in the script describing a visit to a restaurant, typical events are entering the restaurant, ordering food or eating. Participants in this scenario can include animate objects like the waiter and the customer, as well as inanimate objects such as cutlery or food.",
|
| 28 |
+
"Script knowledge has been shown to play an important role in text understanding (cullingford1978script, miikkulainen1995script, mueller2004understanding, Chambers2008, Chambers2009, modi2014inducing, rudinger2015learning). It guides the expectation of the reader, supports coreference resolution as well as common-sense knowledge inference and enables the appropriate embedding of the current sentence into the larger context. Figure 1 shows the first few sentences of a story describing the scenario taking a bath. Once the taking a bath scenario is evoked by the noun phrase (NP) \u201ca bath\u201d, the reader can effortlessly interpret the definite NP \u201cthe faucet\u201d as an implicitly present standard participant of the taking a bath script. Although in this story, \u201centering the bath room\u201d, \u201cturning on the water\u201d and \u201cfilling the tub\u201d are explicitly mentioned, a reader could nevertheless have inferred the \u201cturning on the water\u201d event, even if it was not explicitly mentioned in the text. Table 1 gives an example of typical events and participants for the script describing the scenario taking a bath.",
|
| 29 |
+
"A systematic study of the influence of script knowledge in texts is far from trivial. Typically, text documents (e.g. narrative texts) describing various scenarios evoke many different scripts, making it difficult to study the effect of a single script. Efforts have been made to collect scenario-specific script knowledge via crowdsourcing, for example the OMICS and SMILE corpora (singh2002open, Regneri:2010, Regneri2013), but these corpora describe script events in a pointwise telegram style rather than in full texts.",
|
| 30 |
+
"This paper presents the InScript corpus (Narrative Texts Instantiating Script structure). It is a corpus of simple narrative texts in the form of stories, wherein each story is centered around a specific scenario. The stories have been collected via Amazon Mechanical Turk (M-Turk). In this experiment, turkers were asked to write down a concrete experience about a bus ride, a grocery shopping event etc. We concentrated on 10 scenarios and collected 100 stories per scenario, giving a total of 1,000 stories with about 200,000 words. Relevant verbs and noun phrases in all stories are annotated with event types and participant types respectively. Additionally, the texts have been annotated with coreference information in order to facilitate the study of the interdependence between script structure and coreference.",
|
| 31 |
+
"The InScript corpus is a unique resource that provides a basis for studying various aspects of the role of script knowledge in language processing by humans. The acquisition of this corpus is part of a larger research effort that aims at using script knowledge to model the surprisal and information density in written text. Besides InScript, this project also released a corpus of generic descriptions of script activities called DeScript (for Describing Script Structure, Wanzare2016). DeScript contains a range of short and textually simple phrases that describe script events in the style of OMICS or SMILE (singh2002open, Regneri:2010). These generic telegram-style descriptions are called Event Descriptions (EDs); a sequence of such descriptions that cover a complete script is called an Event Sequence Description (ESD). Figure 2 shows an excerpt of a script in the baking a cake scenario. The figure shows event descriptions for 3 different events in the DeScript corpus (left) and fragments of a story in the InScript corpus (right) that instantiate the same event type."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"We selected 10 scenarios from different available scenario lists (e.g. Regneri:2010 , VanDerMeer2009, and the OMICS corpus BIBREF1 ), including scripts of different complexity (Taking a bath vs. Flying in an airplane) and specificity (Riding a public bus vs. Repairing a flat bicycle tire). For the full scenario list see Table 2 .",
|
| 35 |
+
"Texts were collected via the Amazon Mechanical Turk platform, which provides an opportunity to present an online task to humans (a.k.a. turkers). In order to gauge the effect of different M-Turk instructions on our task, we first conducted pilot experiments with different variants of instructions explaining the task. We finalized the instructions for the full data collection, asking the turkers to describe a scenario in form of a story as if explaining it to a child and to use a minimum of 150 words. The selected instruction variant resulted in comparably simple and explicit scenario-related stories. In the future we plan to collect more complex stories using different instructions. In total 190 turkers participated. All turkers were living in the USA and native speakers of English. We paid USD $0.50 per story to each turker. On average, the turkers took 9.37 minutes per story with a maximum duration of 17.38 minutes."
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"Statistics for the corpus are given in Table 2 . On average, each story has a length of 12 sentences and 217 words with 98 word types on average. Stories are coherent and concentrate mainly on the corresponding scenario. Neglecting auxiliaries, modals and copulas, on average each story has 32 verbs, out of which 58% denote events related to the respective scenario. As can be seen in Table 2 , there is some variation in stories across scenarios: The flying in an airplane scenario, for example, is most complex in terms of the number of sentences, tokens and word types that are used. This is probably due to the inherent complexity of the scenario: Taking a flight, for example, is more complicated and takes more steps than taking a bath. The average count of sentences, tokens and types is also very high for the baking a cake scenario. Stories from the scenario often resemble cake recipes, which usually contain very detailed steps, so people tend to give more detailed descriptions in the stories.",
|
| 39 |
+
"For both flying in an airplane and baking a cake, the standard deviation is higher in comparison to other scenarios. This indicates that different turkers described the scenario with a varying degree of detail and can also be seen as an indicator for the complexity of both scenarios. In general, different people tend to describe situations subjectively, with a varying degree of detail. In contrast, texts from the taking a bath and planting a tree scenarios contain a relatively smaller number of sentences and fewer word types and tokens. Both planting a tree and taking a bath are simpler activities, which results in generally less complex texts.",
|
| 40 |
+
"The average pairwise word type overlap can be seen as a measure of lexical variety among stories: If it is high, the stories resemble each other more. We can see that stories in the flying in an airplane and baking a cake scenarios have the highest values here, indicating that most turkers used a similar vocabulary in their stories.",
|
| 41 |
+
"In general, the response quality was good. We had to discard 9% of the stories as these lacked the quality we were expecting. In total, we selected 910 stories for annotation."
|
| 42 |
+
],
|
| 43 |
+
[
|
| 44 |
+
"This section deals with the annotation of the data. We first describe the final annotation schema. Then, we describe the iterative process of corpus annotation and the refinement of the schema. This refinement was necessary due to the complexity of the annotation."
|
| 45 |
+
],
|
| 46 |
+
[
|
| 47 |
+
"For each of the scenarios, we designed a specific annotation template. A script template consists of scenario-specific event and participant labels. An example of a template is shown in Table 1 . All NP heads in the corpus were annotated with a participant label; all verbs were annotated with an event label. For both participants and events, we also offered the label unclear if the annotator could not assign another label. We additionally annotated coreference chains between NPs. Thus, the process resulted in three layers of annotation: event types, participant types and coreference annotation. These are described in detail below.",
|
| 48 |
+
"As a first layer, we annotated event types. There are two kinds of event type labels, scenario-specific event type labels and general labels. The general labels are used across every scenario and mark general features, for example whether an event belongs to the scenario at all. For the scenario-specific labels, we designed an unique template for every scenario, with a list of script-relevant event types that were used as labels. Such labels include for example ScrEv_close_drain in taking a bath as in Example UID10 (see Figure 1 for a complete list for the taking a bath scenario)",
|
| 49 |
+
"I start by closing $_{\\textsc {\\scriptsize ScrEv\\_close\\_drain}}$ the drain at the bottom of the tub.",
|
| 50 |
+
"The general labels that were used in addition to the script-specific labels in every scenario are listed below:",
|
| 51 |
+
"ScrEv_other. An event that belongs to the scenario, but its event type occurs too infrequently (for details, see below, Section \"Modification of the Schema\" ). We used the label \u201cother\" because event classification would become too finegrained otherwise.",
|
| 52 |
+
"Example: After I am dried I put my new clothes on and clean up $_{\\textsc {\\scriptsize ScrEv\\_other}}$ the bathroom.",
|
| 53 |
+
"RelNScrEv. Related non-script event. An event that can plausibly happen during the execution of the script and is related to it, but that is not part of the script.",
|
| 54 |
+
"Example: After finding on what I wanted to wear, I went into the bathroom and shut $_{\\textsc {\\scriptsize RelNScrEv}}$ the door.",
|
| 55 |
+
"UnrelEv. An event that is unrelated to the script.",
|
| 56 |
+
"Example: I sank into the bubbles and took $_{\\textsc {\\scriptsize UnrelEv}}$ a deep breath.",
|
| 57 |
+
"Additionally, the annotators were asked to annotate verbs and phrases that evoke the script without explicitly referring to a script event with the label Evoking, as shown in Example UID10 . Today I took a bath $_{\\textsc {\\scriptsize Evoking}}$ in my new apartment.",
|
| 58 |
+
"As in the case of the event type labels, there are two kinds of participant labels: general labels and scenario-specific labels. The latter are part of the scenario-specific templates, e.g. ScrPart_drain in the taking a bath scenario, as can be seen in Example UID15 .",
|
| 59 |
+
"I start by closing the drain $_{\\textsc {\\scriptsize ScrPart\\_drain}}$ at the bottom of the tub.",
|
| 60 |
+
"The general labels that are used across all scenarios mark noun phrases with scenario-independent features. There are the following general labels:",
|
| 61 |
+
"ScrPart_other. A participant that belongs to the scenario, but its participant type occurs only infrequently.",
|
| 62 |
+
"Example: I find my bath mat $_{\\textsc {\\scriptsize ScrPart\\_other}}$ and lay it on the floor to keep the floor dry.",
|
| 63 |
+
"NPart. Non-participant. A referential NP that does not belong to the scenario.",
|
| 64 |
+
"Example: I washed myself carefully because I did not want to spill water onto the floor $_{\\textsc {\\scriptsize NPart}}$ .labeled",
|
| 65 |
+
"SuppVComp. A support verb complement. For further discussion of this label, see Section \"Special Cases\" ",
|
| 66 |
+
"Example: I sank into the bubbles and took a deep breath $_{\\textsc {\\scriptsize SuppVComp}}$ .",
|
| 67 |
+
"Head_of_Partitive. The head of a partitive or a partitive-like construction. For a further discussion of this label cf. Section \"Special Cases\" ",
|
| 68 |
+
"Example: I grabbed a bar $_{\\textsc {\\scriptsize Head\\_of\\_Partitive}}$ of soap and lathered my body.",
|
| 69 |
+
"No_label. A non-referential noun phrase that cannot be labeled with another label. Example: I sat for a moment $_{\\textsc {\\scriptsize No\\_label}}$ , relaxing, allowing the warm water to sooth my skin.",
|
| 70 |
+
"All NPs labeled with one of the labels SuppVComp, Head_of_Partitive or No_label are considered to be non-referential. No_label is used mainly in four cases in our data: non-referential time expressions (in a while, a million times better), idioms (no matter what), the non-referential \u201cit\u201d (it felt amazing, it is better) and other abstracta (a lot better, a little bit).",
|
| 71 |
+
"In the first annotation phase, annotators were asked to mark verbs and noun phrases that have an event or participant type, that is not listed in the template, as MissScrEv/ MissScrPart (missing script event or participant, resp.). These annotations were used as a basis for extending the templates (see Section \"Modification of the Schema\" ) and replaced later by newly introduced labels or ScrEv_other and ScrPart_other respectively.",
|
| 72 |
+
"All noun phrases were annotated with coreference information indicating which entities denote the same discourse referent. The annotation was done by linking heads of NPs (see Example UID21 , where the links are indicated by coindexing). As a rule, we assume that each element of a coreference chain is marked with the same participant type label.",
|
| 73 |
+
"I $ _{\\textsc {\\scriptsize Coref1}}$ washed my $ _{\\textsc {\\scriptsize Coref1}}$ entire body $ _{\\textsc {\\scriptsize Coref2}}$ , starting with my $ _{\\textsc {\\scriptsize Coref1}}$ face $ _{\\textsc {\\scriptsize Coref3}} $ and ending with the toes $ _{\\textsc {\\scriptsize Coref4}} $ . I $ _{\\textsc {\\scriptsize Coref1}}$ always wash my $ _{\\textsc {\\scriptsize Coref1}}$ toes $_{\\textsc {\\scriptsize Coref4}}$ very thoroughly ...",
|
| 74 |
+
"The assignment of an entity to a referent is not always trivial, as is shown in Example UID21 . There are some cases in which two discourse referents are grouped in a plural NP. In the example, those things refers to the group made up of shampoo, soap and sponge. In this case, we asked annotators to introduce a new coreference label, the name of which indicates which referents are grouped together (Coref_group_washing_tools). All NPs are then connected to the group phrase, resulting in an additional coreference chain.",
|
| 75 |
+
"I $ _{\\textsc {\\scriptsize Coref1}}$ made sure that I $ _{\\textsc {\\scriptsize Coref1}}$ have my $ _{\\textsc {\\scriptsize Coref1}}$ shampoo $ _{\\textsc {\\scriptsize Coref2 + Coref\\_group\\_washing\\_tools}}$ , soap $_{\\textsc {\\scriptsize Coref3 + Coref\\_group\\_washing\\_tools}}$ and sponge $ _{\\textsc {\\scriptsize Coref4 + Coref\\_group\\_washing\\_tools}}$ ready to get in. Once I $ _{\\textsc {\\scriptsize Coref1}}$ have those things $ _{\\textsc {\\scriptsize Coref\\_group\\_washing\\_tools}}$ I $ _{\\textsc {\\scriptsize Coref1}}$ sink into the bath. ... I $ _{\\textsc {\\scriptsize Coref1}}$ applied some soap $ _{\\textsc {\\scriptsize Coref1}}$0 on my $ _{\\textsc {\\scriptsize Coref1}}$1 body and used the sponge $ _{\\textsc {\\scriptsize Coref1}}$2 to scrub a bit. ... I $ _{\\textsc {\\scriptsize Coref1}}$3 rinsed the shampoo $ _{\\textsc {\\scriptsize Coref1}}$4 . Example UID21 thus contains the following coreference chains: Coref1: I $ _{\\textsc {\\scriptsize Coref1}}$5 I $ _{\\textsc {\\scriptsize Coref1}}$6 my $ _{\\textsc {\\scriptsize Coref1}}$7 I $ _{\\textsc {\\scriptsize Coref1}}$8 I $ _{\\textsc {\\scriptsize Coref1}}$9 I $ _{\\textsc {\\scriptsize Coref1}}$0 my $ _{\\textsc {\\scriptsize Coref1}}$1 I",
|
| 76 |
+
"Coref2: shampoo $\\rightarrow $ shampoo",
|
| 77 |
+
"Coref3: soap $\\rightarrow $ soap",
|
| 78 |
+
"Coref4: sponge $\\rightarrow $ sponge",
|
| 79 |
+
"Coref_group_washing_ tools: shampoo $\\rightarrow $ soap $\\rightarrow $ sponge $\\rightarrow $ things"
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"The templates were carefully designed in an iterated process. For each scenario, one of the authors of this paper provided a preliminary version of the template based on the inspection of some of the stories. For a subset of the scenarios, preliminary templates developed at our department for a psycholinguistic experiment on script knowledge were used as a starting point. Subsequently, the authors manually annotated 5 randomly selected texts for each of the scenarios based on the preliminary template. Necessary extensions and changes in the templates were discussed and agreed upon. Most of the cases of disagreement were related to the granularity of the event and participant types. We agreed on the script-specific functional equivalence as a guiding principle. For example, reading a book, listening to music and having a conversation are subsumed under the same event label in the flight scenario, because they have the common function of in-flight entertainment in the scenario. In contrast, we assumed different labels for the cake tin and other utensils (bowls etc.), since they have different functions in the baking a cake scenario and accordingly occur with different script events.",
|
| 83 |
+
"Note that scripts and templates as such are not meant to describe an activity as exhaustively as possible and to mention all steps that are logically necessary. Instead, scripts describe cognitively prominent events in an activity. An example can be found in the flight scenario. While more than a third of the turkers mentioned the event of fastening the seat belts in the plane (buckle_seat_belt), no person wrote about undoing their seat belts again, although in reality both events appear equally often. Consequently, we added an event type label for buckling up, but no label for undoing the seat belts."
|
| 84 |
+
],
|
| 85 |
+
[
|
| 86 |
+
"We used the WebAnno annotation tool BIBREF2 for our project. The stories from each scenario were distributed among four different annotators. In a calibration phase, annotators were presented with some sample texts for test annotations; the results were discussed with the authors. Throughout the whole annotation phase, annotators could discuss any emerging issues with the authors. All annotations were done by undergraduate students of computational linguistics. The annotation was rather time-consuming due to the complexity of the task, and thus we decided for single annotation mode. To assess annotation quality, a small sample of texts was annotated by all four annotators and their inter-annotator agreement was measured (see Section \"Inter-Annotator Agreement\" ). It was found to be sufficiently high.",
|
| 87 |
+
"Annotation of the corpus together with some pre- and post-processing of the data required about 500 hours of work. All stories were annotated with event and participant types (a total of 12,188 and 43,946 instances, respectively). On average there were 7 coreference chains per story with an average length of 6 tokens."
|
| 88 |
+
],
|
| 89 |
+
[
|
| 90 |
+
"After the first annotation round, we extended and changed the templates based on the results. As mentioned before, we used MissScrEv and MissScrPart labels to mark verbs and noun phrases instantiating events and participants for which no appropriate labels were available in the templates. Based on the instances with these labels (a total of 941 and 1717 instances, respectively), we extended the guidelines to cover the sufficiently frequent cases. In order to include new labels for event and participant types, we tried to estimate the number of instances that would fall under a certain label. We added new labels according to the following conditions:",
|
| 91 |
+
"For the participant annotations, we added new labels for types that we expected to appear at least 10 times in total in at least 5 different stories (i.e. in approximately 5% of the stories).",
|
| 92 |
+
"For the event annotations, we chose those new labels for event types that would appear in at least 5 different stories.",
|
| 93 |
+
"In order to avoid too fine a granularity of the templates, all other instances of MissScrEv and MissScrPart were re-labeled with ScrEv_other and ScrPart_other. We also relabeled participants and events from the first annotation phase with ScrEv_other and ScrPart_other, if they did not meet the frequency requirements. The event label air_bathroom (the event of letting fresh air into the room after the bath), for example, was only used once in the stories, so we relabeled that instance to ScrEv_other.",
|
| 94 |
+
"Additionally, we looked at the DeScript corpus BIBREF3 , which contains manually clustered event paraphrase sets for the 10 scenarios that are also covered by InScript (see Section \"Comparison to the DeScript Corpus\" ). Every such set contains event descriptions that describe a certain event type. We extended our templates with additional labels for these events, if they were not yet part of the template."
|
| 95 |
+
],
|
| 96 |
+
[
|
| 97 |
+
"Noun-noun compounds were annotated twice with the same label (whole span plus the head noun), as indicated by Example UID31 . This redundant double annotation is motivated by potential processing requirements.",
|
| 98 |
+
"I get my (wash (cloth $ _{\\textsc {\\scriptsize ScrPart\\_washing\\_tools}} ))$ , $_{\\textsc {\\scriptsize ScrPart\\_washing\\_tools}} $ and put it under the water.",
|
| 99 |
+
"A special treatment was given to support verb constructions such as take time, get home or take a seat in Example UID32 . The semantics of the verb itself is highly underspecified in such constructions; the event type is largely dependent on the object NP. As shown in Example UID32 , we annotate the head verb with the event type described by the whole construction and label its object with SuppVComp (support verb complement), indicating that it does not have a proper reference.",
|
| 100 |
+
"I step into the tub and take $ _{\\textsc {\\scriptsize ScrEv\\_sink\\_water}} $ a seat $ _{\\textsc {\\scriptsize SuppVComp}} $ .",
|
| 101 |
+
"We used the Head_of_Partitive label for the heads in partitive constructions, assuming that the only referential part of the construction is the complement. This is not completely correct, since different partitive heads vary in their degree of concreteness (cf. Examples UID33 and UID33 ), but we did not see a way to make the distinction sufficiently transparent to the annotators. Our seats were at the back $ _{\\textsc {\\scriptsize Head\\_of\\_Partitive}} $ of the train $ _{\\textsc {\\scriptsize ScrPart\\_train}} $ . In the library you can always find a couple $ _{\\textsc {\\scriptsize Head\\_of\\_Partitive}} $ of interesting books $ _{\\textsc {\\scriptsize ScrPart\\_book}} $ .",
|
| 102 |
+
"Group denoting NPs sometimes refer to groups whose members are instances of different participant types. In Example UID34 , the first-person plural pronoun refers to the group consisting of the passenger (I) and a non-participant (my friend). To avoid a proliferation of event type labels, we labeled these cases with Unclear.",
|
| 103 |
+
"I $ _{\\textsc {\\scriptsize {ScrPart\\_passenger}}}$ wanted to visit my $_{\\textsc {\\scriptsize {ScrPart\\_passenger}}}$ friend $ _{\\textsc {\\scriptsize {NPart}}}$ in New York. ... We $_{\\textsc {\\scriptsize Unclear}}$ met at the train station.",
|
| 104 |
+
"We made an exception for the Getting a Haircut scenario, where the mixed participant group consisting of the hairdresser and the customer occurs very often, as in Example UID34 . Here, we introduced the additional ad-hoc participant label Scr_Part_hairdresser_customer.",
|
| 105 |
+
"While Susan $_{\\textsc {\\scriptsize {ScrPart\\_hairdresser}}}$ is cutting my $_{\\textsc {\\scriptsize {ScrPart\\_customer}}}$ hair we $_{\\textsc {\\scriptsize Scr\\_Part\\_hairdresser\\_customer}}$ usually talk a bit."
|
| 106 |
+
],
|
| 107 |
+
[
|
| 108 |
+
"In order to calculate inter-annotator agreement, a total of 30 stories from 6 scenarios were randomly chosen for parallel annotation by all 4 annotators after the first annotation phase. We checked the agreement on these data using Fleiss' Kappa BIBREF4 . The results are shown in Figure 4 and indicate moderate to substantial agreement BIBREF5 . Interestingly, if we calculated the Kappa only on the subset of cases that were annotated with script-specific event and participant labels by all annotators, results were better than those of the evaluation on all labeled instances (including also unrelated and related non-script events). This indicates one of the challenges of the annotation task: In many cases it is difficult to decide whether a particular event should be considered a central script event, or an event loosely related or unrelated to the script.",
|
| 109 |
+
"For coreference chain annotation, we calculated the percentage of pairs which were annotated by at least 3 annotators (qualified majority vote) compared to the set of those pairs annotated by at least one person (see Figure 4 ). We take the result of 90.5% between annotators to be a good agreement."
|
| 110 |
+
],
|
| 111 |
+
[
|
| 112 |
+
"Figure 5 gives an overview of the number of event and participant types provided in the templates. Taking a flight and getting a haircut stand out with a large number of both event and participant types, which is due to the inherent complexity of the scenarios. In contrast, planting a tree and going on a train contain the fewest labels. There are 19 event and participant types on average.",
|
| 113 |
+
"Figure 6 presents overview statistics about the usage of event labels, participant labels and coreference chain annotations. As can be seen, there are usually many more mentions of participants than events. For coreference chains, there are some chains that are really long (which also results in a large scenario-wise standard deviation). Usually, these chains describe the protagonist.",
|
| 114 |
+
"We also found again that the flying in an airplane scenario stands out in terms of participant mentions, event mentions and average number of coreference chains.",
|
| 115 |
+
"Figure 7 shows for every participant label in the baking a cake scenario the number of stories which they occurred in. This indicates how relevant a participant is for the script. As can be seen, a small number of participants are highly prominent: cook, ingredients and cake are mentioned in every story. The fact that the protagonist appears most often consistently holds for all other scenarios, where the acting person appears in every story, and is mentioned most frequently.",
|
| 116 |
+
"Figure 8 shows the distribution of participant/event type labels over all appearances over all scenarios on average. The groups stand for the most frequently appearing label, the top 2 to 5 labels in terms of frequency and the top 6 to 10. ScrEv_other and ScrPart_other are shown separately. As can be seen, the most frequently used participant label (the protagonist) makes up about 40% of overall participant instances. The four labels that follow the protagonist in terms of frequency together appear in 37% of the cases. More than 2 out of 3 participants in total belong to one of only 5 labels.",
|
| 117 |
+
"In contrast, the distribution for events is more balanced. 14% of all event instances have the most prominent event type. ScrEv_other and ScrPart_other both appear as labels in at most 5% of all event and participant instantiations: The specific event and participant type labels in our templates cover by far most of the instances.",
|
| 118 |
+
"In Figure 9 , we grouped participants similarly into the first, the top 2-5 and top 6-10 most frequently appearing participant types. The figure shows for each of these groups the average frequency per story, and in the rightmost column the overall average. The results correspond to the findings from the last paragraph."
|
| 119 |
+
],
|
| 120 |
+
[
|
| 121 |
+
"As mentioned previously, the InScript corpus is part of a larger research project, in which also a corpus of a different kind, the DeScript corpus, was created. DeScript covers 40 scenarios, and also contains the 10 scenarios from InScript. This corpus contains texts that describe scripts on an abstract and generic level, while InScript contains instantiations of scripts in narrative texts. Script events in DeScript are described in a very simple, telegram-style language (see Figure 2 ). Since one of the long-term goals of the project is to align the InScript texts with the script structure given from DeScript, it is interesting to compare both resources.",
|
| 122 |
+
"The InScript corpus exhibits much more lexical variation than DeScript. Many approaches use the type-token ratio to measure this variance. However, this measure is known to be sensitive to text length (see e.g. Tweedie1998), which would result in very small values for InScript and relatively large ones for DeScript, given the large average difference of text lengths between the corpora. Instead, we decided to use the Measure of Textual Lexical Diversity (MTLD) (McCarthy2010, McCarthy2005), which is familiar in corpus linguistics. This metric measures the average number of tokens in a text that are needed to retain a type-token ratio above a certain threshold. If the MTLD for a text is high, many tokens are needed to lower the type-token ratio under the threshold, so the text is lexically diverse. In contrast, a low MTLD indicates that only a few words are needed to make the type-token ratio drop, so the lexical diversity is smaller. We use the threshold of 0.71, which is proposed by the authors as a well-proven value.",
|
| 123 |
+
"Figure 10 compares the lexical diversity of both resources. As can be seen, the InScript corpus with its narrative texts is generally much more diverse than the DeScript corpus with its short event descriptions, across all scenarios. For both resources, the flying in an airplane scenario is most diverse (as was also indicated above by the mean word type overlap). However, the difference in the variation of lexical variance of scenarios is larger for DeScript than for InScript. Thus, the properties of a scenario apparently influence the lexical variance of the event descriptions more than the variance of the narrative texts. We used entropy BIBREF6 over lemmas to measure the variance of lexical realizations for events. We excluded events for which there were less than 10 occurrences in DeScript or InScript. Since there is only an event annotation for 50 ESDs per scenario in DeScript, we randomly sampled 50 texts from InScript for computing the entropy to make the numbers more comparable.",
|
| 124 |
+
"Figure 11 shows as an example the entropy values for the event types in the going on a train scenario. As can be seen in the graph, the entropy for InScript is in general higher than for DeScript. In the stories, a wider variety of verbs is used to describe events. There are also large differences between events: While wait has a really low entropy, spend_time_train has an extremely high entropy value. This event type covers many different activities such as reading, sleeping etc."
|
| 125 |
+
],
|
| 126 |
+
[
|
| 127 |
+
"In this paper we described the InScript corpus of 1,000 narrative texts annotated with script structure and coreference information. We described the annotation process, various difficulties encountered during annotation and different remedies that were taken to overcome these. One of the future research goals of our project is also concerned with finding automatic methods for text-to-script mapping, i.e. for the alignment of text segments with script states. We consider InScript and DeScript together as a resource for studying this alignment. The corpus shows rich lexical variation and will serve as a unique resource for the study of the role of script knowledge in natural language processing."
|
| 128 |
+
],
|
| 129 |
+
[
|
| 130 |
+
"This research was funded by the German Research Foundation (DFG) as part of SFB 1102 'Information Density and Linguistic Encoding'."
|
| 131 |
+
]
|
| 132 |
+
]
|
| 133 |
+
}
|
| 134 |
+
```
|
qasper-0147/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: Investigating Robustness and Interpretability of Link Prediction via Adversarial Modifications
|
| 2 |
+
|
| 3 |
+
Question: What datasets are used to evaluate this approach?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Background and Notation",
|
| 12 |
+
"Completion Robustness and Interpretability via Adversarial Graph Edits ()",
|
| 13 |
+
"Removing a fact ()",
|
| 14 |
+
"Adding a new fact ()",
|
| 15 |
+
"Challenges",
|
| 16 |
+
"Efficiently Identifying the Modification",
|
| 17 |
+
"First-order Approximation of Influence",
|
| 18 |
+
"Continuous Optimization for Search",
|
| 19 |
+
"Experiments",
|
| 20 |
+
"Influence Function vs ",
|
| 21 |
+
"Robustness of Link Prediction Models",
|
| 22 |
+
"Interpretability of Models",
|
| 23 |
+
"Finding Errors in Knowledge Graphs",
|
| 24 |
+
"Related Work",
|
| 25 |
+
"Conclusions",
|
| 26 |
+
"Acknowledgements",
|
| 27 |
+
"Appendix",
|
| 28 |
+
"Modifications of the Form \u2329s,r ' ,o ' \u232a\\langle s, r^{\\prime }, o^{\\prime } \\rangle ",
|
| 29 |
+
"Modifications of the Form \u2329s,r ' ,o\u232a\\langle s, r^{\\prime }, o \\rangle ",
|
| 30 |
+
"First-order Approximation of the Change For TransE",
|
| 31 |
+
"Sample Adversarial Attacks"
|
| 32 |
+
],
|
| 33 |
+
"paragraphs": [
|
| 34 |
+
[
|
| 35 |
+
"Knowledge graphs (KG) play a critical role in many real-world applications such as search, structured data management, recommendations, and question answering. Since KGs often suffer from incompleteness and noise in their facts (links), a number of recent techniques have proposed models that embed each entity and relation into a vector space, and use these embeddings to predict facts. These dense representation models for link prediction include tensor factorization BIBREF0 , BIBREF1 , BIBREF2 , algebraic operations BIBREF3 , BIBREF4 , BIBREF5 , multiple embeddings BIBREF6 , BIBREF7 , BIBREF8 , BIBREF9 , and complex neural models BIBREF10 , BIBREF11 . However, there are only a few studies BIBREF12 , BIBREF13 that investigate the quality of the different KG models. There is a need to go beyond just the accuracy on link prediction, and instead focus on whether these representations are robust and stable, and what facts they make use of for their predictions. In this paper, our goal is to design approaches that minimally change the graph structure such that the prediction of a target fact changes the most after the embeddings are relearned, which we collectively call Completion Robustness and Interpretability via Adversarial Graph Edits (). First, we consider perturbations that red!50!blackremove a neighboring link for the target fact, thus identifying the most influential related fact, providing an explanation for the model's prediction. As an example, consider the excerpt from a KG in Figure 1 with two observed facts, and a target predicted fact that Princes Henriette is the parent of Violante Bavaria. Our proposed graph perturbation, shown in Figure 1 , identifies the existing fact that Ferdinal Maria is the father of Violante Bavaria as the one when removed and model retrained, will change the prediction of Princes Henriette's child. We also study attacks that green!50!blackadd a new, fake fact into the KG to evaluate the robustness and sensitivity of link prediction models to small additions to the graph. An example attack for the original graph in Figure 1 , is depicted in Figure 1 . Such perturbations to the the training data are from a family of adversarial modifications that have been applied to other machine learning tasks, known as poisoning BIBREF14 , BIBREF15 , BIBREF16 , BIBREF17 .",
|
| 36 |
+
"Since the setting is quite different from traditional adversarial attacks, search for link prediction adversaries brings up unique challenges. To find these minimal changes for a target link, we need to identify the fact that, when added into or removed from the graph, will have the biggest impact on the predicted score of the target fact. Unfortunately, computing this change in the score is expensive since it involves retraining the model to recompute the embeddings. We propose an efficient estimate of this score change by approximating the change in the embeddings using Taylor expansion. The other challenge in identifying adversarial modifications for link prediction, especially when considering addition of fake facts, is the combinatorial search space over possible facts, which is intractable to enumerate. We introduce an inverter of the original embedding model, to decode the embeddings to their corresponding graph components, making the search of facts tractable by performing efficient gradient-based continuous optimization. We evaluate our proposed methods through following experiments. First, on relatively small KGs, we show that our approximations are accurate compared to the true change in the score. Second, we show that our additive attacks can effectively reduce the performance of state of the art models BIBREF2 , BIBREF10 up to $27.3\\%$ and $50.7\\%$ in Hits@1 for two large KGs: WN18 and YAGO3-10. We also explore the utility of adversarial modifications in explaining the model predictions by presenting rule-like descriptions of the most influential neighbors. Finally, we use adversaries to detect errors in the KG, obtaining up to $55\\%$ accuracy in detecting errors."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"In this section, we briefly introduce some notations, and existing relational embedding approaches that model knowledge graph completion using dense vectors. In KGs, facts are represented using triples of subject, relation, and object, $\\langle s, r, o\\rangle $ , where $s,o\\in \\xi $ , the set of entities, and $r\\in $ , the set of relations. To model the KG, a scoring function $\\psi :\\xi \\times \\times \\xi \\rightarrow $ is learned to evaluate whether any given fact is true. In this work, we focus on multiplicative models of link prediction, specifically DistMult BIBREF2 because of its simplicity and popularity, and ConvE BIBREF10 because of its high accuracy. We can represent the scoring function of such methods as $\\psi (s,r,o) = , ) \\cdot $ , where $,,\\in ^d$ are embeddings of the subject, relation, and object respectively. In DistMult, $, ) = \\odot $ , where $\\odot $ is element-wise multiplication operator. Similarly, in ConvE, $, )$ is computed by a convolution on the concatenation of $$ and $s,o\\in \\xi $0 .",
|
| 40 |
+
"We use the same setup as BIBREF10 for training, i.e., incorporate binary cross-entropy loss over the triple scores. In particular, for subject-relation pairs $(s,r)$ in the training data $G$ , we use binary $y^{s,r}_o$ to represent negative and positive facts. Using the model's probability of truth as $\\sigma (\\psi (s,r,o))$ for $\\langle s,r,o\\rangle $ , the loss is defined as: (G) = (s,r)o ys,ro(((s,r,o)))",
|
| 41 |
+
"+ (1-ys,ro)(1 - ((s,r,o))). Gradient descent is used to learn the embeddings $,,$ , and the parameters of $, if any.\n$ "
|
| 42 |
+
],
|
| 43 |
+
[
|
| 44 |
+
"For adversarial modifications on KGs, we first define the space of possible modifications. For a target triple $\\langle s, r, o\\rangle $ , we constrain the possible triples that we can remove (or inject) to be in the form of $\\langle s^{\\prime }, r^{\\prime }, o\\rangle $ i.e $s^{\\prime }$ and $r^{\\prime }$ may be different from the target, but the object is not. We analyze other forms of modifications such as $\\langle s, r^{\\prime }, o^{\\prime }\\rangle $ and $\\langle s, r^{\\prime }, o\\rangle $ in appendices \"Modifications of the Form \u2329s,r ' ,o ' \u232a\\langle s, r^{\\prime }, o^{\\prime } \\rangle \" and \"Modifications of the Form \u2329s,r ' ,o\u232a\\langle s, r^{\\prime }, o \\rangle \" , and leave empirical evaluation of these modifications for future work."
|
| 45 |
+
],
|
| 46 |
+
[
|
| 47 |
+
"For explaining a target prediction, we are interested in identifying the observed fact that has the most influence (according to the model) on the prediction. We define influence of an observed fact on the prediction as the change in the prediction score if the observed fact was not present when the embeddings were learned. Previous work have used this concept of influence similarly for several different tasks BIBREF19 , BIBREF20 . Formally, for the target triple ${s,r,o}$ and observed graph $G$ , we want to identify a neighboring triple ${s^{\\prime },r^{\\prime },o}\\in G$ such that the score $\\psi (s,r,o)$ when trained on $G$ and the score $\\overline{\\psi }(s,r,o)$ when trained on $G-\\lbrace {s^{\\prime },r^{\\prime },o}\\rbrace $ are maximally different, i.e. *argmax(s', r')Nei(o) (s',r')(s,r,o) where $\\Delta _{(s^{\\prime },r^{\\prime })}(s,r,o)=\\psi (s, r, o)-\\overline{\\psi }(s,r,o)$ , and $\\text{Nei}(o)=\\lbrace (s^{\\prime },r^{\\prime })|\\langle s^{\\prime },r^{\\prime },o \\rangle \\in G \\rbrace $ ."
|
| 48 |
+
],
|
| 49 |
+
[
|
| 50 |
+
"We are also interested in investigating the robustness of models, i.e., how sensitive are the predictions to small additions to the knowledge graph. Specifically, for a target prediction ${s,r,o}$ , we are interested in identifying a single fake fact ${s^{\\prime },r^{\\prime },o}$ that, when added to the knowledge graph $G$ , changes the prediction score $\\psi (s,r,o)$ the most. Using $\\overline{\\psi }(s,r,o)$ as the score after training on $G\\cup \\lbrace {s^{\\prime },r^{\\prime },o}\\rbrace $ , we define the adversary as: *argmax(s', r') (s',r')(s,r,o) where $\\Delta _{(s^{\\prime },r^{\\prime })}(s,r,o)=\\psi (s, r, o)-\\overline{\\psi }(s,r,o)$ . The search here is over any possible $s^{\\prime }\\in \\xi $ , which is often in the millions for most real-world KGs, and $r^{\\prime }\\in $ . We also identify adversaries that increase the prediction score for specific false triple, i.e., for a target fake fact ${s,r,o}$ , the adversary is ${s^{\\prime },r^{\\prime },o}$0 , where ${s^{\\prime },r^{\\prime },o}$1 is defined as before."
|
| 51 |
+
],
|
| 52 |
+
[
|
| 53 |
+
"There are a number of crucial challenges when conducting such adversarial attack on KGs. First, evaluating the effect of changing the KG on the score of the target fact ( $\\overline{\\psi }(s,r,o)$ ) is expensive since we need to update the embeddings by retraining the model on the new graph; a very time-consuming process that is at least linear in the size of $G$ . Second, since there are many candidate facts that can be added to the knowledge graph, identifying the most promising adversary through search-based methods is also expensive. Specifically, the search size for unobserved facts is $|\\xi | \\times ||$ , which, for example in YAGO3-10 KG, can be as many as $4.5 M$ possible facts for a single target prediction."
|
| 54 |
+
],
|
| 55 |
+
[
|
| 56 |
+
"In this section, we propose algorithms to address mentioned challenges by (1) approximating the effect of changing the graph on a target prediction, and (2) using continuous optimization for the discrete search over potential modifications."
|
| 57 |
+
],
|
| 58 |
+
[
|
| 59 |
+
"We first study the addition of a fact to the graph, and then extend it to cover removal as well. To capture the effect of an adversarial modification on the score of a target triple, we need to study the effect of the change on the vector representations of the target triple. We use $$ , $$ , and $$ to denote the embeddings of $s,r,o$ at the solution of $\\operatornamewithlimits{argmin} (G)$ , and when considering the adversarial triple $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ , we use $$ , $$ , and $$ for the new embeddings of $s,r,o$ , respectively. Thus $$0 is a solution to $$1 , which can also be written as $$2 . Similarly, $$3 s', r', o $$4 $$5 $$6 $$7 o $$8 $$9 $$0 $$1 $$2 $$3 O(n3) $$4 $$5 $$6 (s,r,o)-(s, r, o) $$7 - $$8 s, r = ,) $$9 - $s,r,o$0 (G)= (G)+(s', r', o ) $s,r,o$1 $s,r,o$2 s', r' = ',') $s,r,o$3 = ((s',r',o)) $s,r,o$4 eo (G)=0 $s,r,o$5 eo (G) $s,r,o$6 Ho $s,r,o$7 dd $s,r,o$8 o $s,r,o$9 $\\operatornamewithlimits{argmin} (G)$0 - $\\operatornamewithlimits{argmin} (G)$1 -= $\\operatornamewithlimits{argmin} (G)$2 Ho $\\operatornamewithlimits{argmin} (G)$3 Ho + (1-) s',r's',r' $\\operatornamewithlimits{argmin} (G)$4 Ho $\\operatornamewithlimits{argmin} (G)$5 dd $\\operatornamewithlimits{argmin} (G)$6 d $\\operatornamewithlimits{argmin} (G)$7 s,r,s',r'd $\\operatornamewithlimits{argmin} (G)$8 s, r, o $\\operatornamewithlimits{argmin} (G)$9 s', r', o $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $0 $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $1 $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $2 "
|
| 60 |
+
],
|
| 61 |
+
[
|
| 62 |
+
"Using the approximations provided in the previous section, Eq. () and (), we can use brute force enumeration to find the adversary $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ . This approach is feasible when removing an observed triple since the search space of such modifications is usually small; it is the number of observed facts that share the object with the target. On the other hand, finding the most influential unobserved fact to add requires search over a much larger space of all possible unobserved facts (that share the object). Instead, we identify the most influential unobserved fact $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ by using a gradient-based algorithm on vector $_{s^{\\prime },r^{\\prime }}$ in the embedding space (reminder, $_{s^{\\prime },r^{\\prime }}=^{\\prime },^{\\prime })$ ), solving the following continuous optimization problem in $^d$ : *argmaxs', r' (s',r')(s,r,o). After identifying the optimal $_{s^{\\prime }, r^{\\prime }}$ , we still need to generate the pair $(s^{\\prime },r^{\\prime })$ . We design a network, shown in Figure 2 , that maps the vector $_{s^{\\prime },r^{\\prime }}$ to the entity-relation space, i.e., translating it into $(s^{\\prime },r^{\\prime })$ . In particular, we train an auto-encoder where the encoder is fixed to receive the $s$ and $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $0 as one-hot inputs, and calculates $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $1 in the same way as the DistMult and ConvE encoders respectively (using trained embeddings). The decoder is trained to take $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $2 as input and produce $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $3 and $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $4 , essentially inverting $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $5 s, r $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $6 s $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $7 r $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $8 s, r $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $9 We evaluate the performance of our inverter networks (one for each model/dataset) on correctly recovering the pairs of subject and relation from the test set of our benchmarks, given the $_{s^{\\prime },r^{\\prime }}$0 . The accuracy of recovered pairs (and of each argument) is given in Table 1 . As shown, our networks achieve a very high accuracy, demonstrating their ability to invert vectors $_{s^{\\prime },r^{\\prime }}$1 to $_{s^{\\prime },r^{\\prime }}$2 pairs."
|
| 63 |
+
],
|
| 64 |
+
[
|
| 65 |
+
"We evaluate by ( \"Influence Function vs \" ) comparing estimate with the actual effect of the attacks, ( \"Robustness of Link Prediction Models\" ) studying the effect of adversarial attacks on evaluation metrics, ( \"Interpretability of Models\" ) exploring its application to the interpretability of KG representations, and ( \"Finding Errors in Knowledge Graphs\" ) detecting incorrect triples."
|
| 66 |
+
],
|
| 67 |
+
[
|
| 68 |
+
"To evaluate the quality of our approximations and compare with influence function (IF), we conduct leave one out experiments. In this setup, we take all the neighbors of a random target triple as candidate modifications, remove them one at a time, retrain the model each time, and compute the exact change in the score of the target triple. We can use the magnitude of this change in score to rank the candidate triples, and compare this exact ranking with ranking as predicted by: , influence function with and without Hessian matrix, and the original model score (with the intuition that facts that the model is most confident of will have the largest impact when removed). Similarly, we evaluate by considering 200 random triples that share the object entity with the target sample as candidates, and rank them as above. The average results of Spearman's $\\rho $ and Kendall's $\\tau $ rank correlation coefficients over 10 random target samples is provided in Table 3 . performs comparably to the influence function, confirming that our approximation is accurate. Influence function is slightly more accurate because they use the complete Hessian matrix over all the parameters, while we only approximate the change by calculating the Hessian over $$ . The effect of this difference on scalability is dramatic, constraining IF to very small graphs and small embedding dimensionality ( $d\\le 10$ ) before we run out of memory. In Figure 3 , we show the time to compute a single adversary by IF compared to , as we steadily grow the number of entities (randomly chosen subgraphs), averaged over 10 random triples. As it shows, is mostly unaffected by the number of entities while IF increases quadratically. Considering that real-world KGs have tens of thousands of times more entities, making IF unfeasible for them."
|
| 69 |
+
],
|
| 70 |
+
[
|
| 71 |
+
"Now we evaluate the effectiveness of to successfully attack link prediction by adding false facts. The goal here is to identify the attacks for triples in the test data, and measuring their effect on MRR and Hits@ metrics (ranking evaluations) after conducting the attack and retraining the model.",
|
| 72 |
+
"Since this is the first work on adversarial attacks for link prediction, we introduce several baselines to compare against our method. For finding the adversarial fact to add for the target triple $\\langle s, r, o \\rangle $ , we consider two baselines: 1) choosing a random fake fact $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ (Random Attack); 2) finding $(s^{\\prime }, r^{\\prime })$ by first calculating $, )$ and then feeding $-, )$ to the decoder of the inverter function (Opposite Attack). In addition to , we introduce two other alternatives of our method: (1) , that uses to increase the score of fake fact over a test triple, i.e., we find the fake fact the model ranks second after the test triple, and identify the adversary for them, and (2) that selects between and attacks based on which has a higher estimated change in score.",
|
| 73 |
+
"All-Test The result of the attack on all test facts as targets is provided in the Table 4 . outperforms the baselines, demonstrating its ability to effectively attack the KG representations. It seems DistMult is more robust against random attacks, while ConvE is more robust against designed attacks. is more effective than since changing the score of a fake fact is easier than of actual facts; there is no existing evidence to support fake facts. We also see that YAGO3-10 models are more robust than those for WN18. Looking at sample attacks (provided in Appendix \"Sample Adversarial Attacks\" ), mostly tries to change the type of the target object by associating it with a subject and a relation for a different entity type.",
|
| 74 |
+
"Uncertain-Test To better understand the effect of attacks, we consider a subset of test triples that 1) the model predicts correctly, 2) difference between their scores and the negative sample with the highest score is minimum. This \u201cUncertain-Test\u201d subset contains 100 triples from each of the original test sets, and we provide results of attacks on this data in Table 4 . The attacks are much more effective in this scenario, causing a considerable drop in the metrics. Further, in addition to significantly outperforming other baselines, they indicate that ConvE's confidence is much more robust.",
|
| 75 |
+
"Relation Breakdown We perform additional analysis on the YAGO3-10 dataset to gain a deeper understanding of the performance of our model. As shown in Figure 4 , both DistMult and ConvE provide a more robust representation for isAffiliatedTo and isConnectedTo relations, demonstrating the confidence of models in identifying them. Moreover, the affects DistMult more in playsFor and isMarriedTo relations while affecting ConvE more in isConnectedTo relations.",
|
| 76 |
+
"Examples Sample adversarial attacks are provided in Table 5 . attacks mostly try to change the type of the target triple's object by associating it with a subject and a relation that require a different entity types."
|
| 77 |
+
],
|
| 78 |
+
[
|
| 79 |
+
"To be able to understand and interpret why a link is predicted using the opaque, dense embeddings, we need to find out which part of the graph was most influential on the prediction. To provide such explanations for each predictions, we identify the most influential fact using . Instead of focusing on individual predictions, we aggregate the explanations over the whole dataset for each relation using a simple rule extraction technique: we find simple patterns on subgraphs that surround the target triple and the removed fact from , and appear more than $90\\%$ of the time. We only focus on extracting length-2 horn rules, i.e., $R_1(a,c)\\wedge R_2(c,b)\\Rightarrow R(a,b)$ , where $R(a,b)$ is the target and $R_2(c,b)$ is the removed fact. Table 6 shows extracted YAGO3-10 rules that are common to both models, and ones that are not. The rules show several interesting inferences, such that hasChild is often inferred via married parents, and isLocatedIn via transitivity. There are several differences in how the models reason as well; DistMult often uses the hasCapital as an intermediate step for isLocatedIn, while ConvE incorrectly uses isNeighbor. We also compare against rules extracted by BIBREF2 for YAGO3-10 that utilizes the structure of DistMult: they require domain knowledge on types and cannot be applied to ConvE. Interestingly, the extracted rules contain all the rules provided by , demonstrating that can be used to accurately interpret models, including ones that are not interpretable, such as ConvE. These are preliminary steps toward interpretability of link prediction models, and we leave more analysis of interpretability to future work."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"Here, we demonstrate another potential use of adversarial modifications: finding erroneous triples in the knowledge graph. Intuitively, if there is an error in the graph, the triple is likely to be inconsistent with its neighborhood, and thus the model should put least trust on this triple. In other words, the error triple should have the least influence on the model's prediction of the training data. Formally, to find the incorrect triple $\\langle s^{\\prime }, r^{\\prime }, o\\rangle $ in the neighborhood of the train triple $\\langle s, r, o\\rangle $ , we need to find the triple $\\langle s^{\\prime },r^{\\prime },o\\rangle $ that results in the least change $\\Delta _{(s^{\\prime },r^{\\prime })}(s,r,o)$ when removed from the graph.",
|
| 83 |
+
"To evaluate this application, we inject random triples into the graph, and measure the ability of to detect the errors using our optimization. We consider two types of incorrect triples: 1) incorrect triples in the form of $\\langle s^{\\prime }, r, o\\rangle $ where $s^{\\prime }$ is chosen randomly from all of the entities, and 2) incorrect triples in the form of $\\langle s^{\\prime }, r^{\\prime }, o\\rangle $ where $s^{\\prime }$ and $r^{\\prime }$ are chosen randomly. We choose 100 random triples from the observed graph, and for each of them, add an incorrect triple (in each of the two scenarios) to its neighborhood. Then, after retraining DistMult on this noisy training data, we identify error triples through a search over the neighbors of the 100 facts. The result of choosing the neighbor with the least influence on the target is provided in the Table 7 . When compared with baselines that randomly choose one of the neighbors, or assume that the fact with the lowest score is incorrect, we see that outperforms both of these with a considerable gap, obtaining an accuracy of $42\\%$ and $55\\%$ in detecting errors."
|
| 84 |
+
],
|
| 85 |
+
[
|
| 86 |
+
"Learning relational knowledge representations has been a focus of active research in the past few years, but to the best of our knowledge, this is the first work on conducting adversarial modifications on the link prediction task. Knowledge graph embedding There is a rich literature on representing knowledge graphs in vector spaces that differ in their scoring functions BIBREF21 , BIBREF22 , BIBREF23 . Although is primarily applicable to multiplicative scoring functions BIBREF0 , BIBREF1 , BIBREF2 , BIBREF24 , these ideas apply to additive scoring functions BIBREF18 , BIBREF6 , BIBREF7 , BIBREF25 as well, as we show in Appendix \"First-order Approximation of the Change For TransE\" .",
|
| 87 |
+
"Furthermore, there is a growing body of literature that incorporates an extra types of evidence for more informed embeddings such as numerical values BIBREF26 , images BIBREF27 , text BIBREF28 , BIBREF29 , BIBREF30 , and their combinations BIBREF31 . Using , we can gain a deeper understanding of these methods, especially those that build their embeddings wit hmultiplicative scoring functions.",
|
| 88 |
+
"Interpretability and Adversarial Modification There has been a significant recent interest in conducting an adversarial attacks on different machine learning models BIBREF16 , BIBREF32 , BIBREF33 , BIBREF34 , BIBREF35 , BIBREF36 to attain the interpretability, and further, evaluate the robustness of those models. BIBREF20 uses influence function to provide an approach to understanding black-box models by studying the changes in the loss occurring as a result of changes in the training data. In addition to incorporating their established method on KGs, we derive a novel approach that differs from their procedure in two ways: (1) instead of changes in the loss, we consider the changes in the scoring function, which is more appropriate for KG representations, and (2) in addition to searching for an attack, we introduce a gradient-based method that is much faster, especially for \u201cadding an attack triple\u201d (the size of search space make the influence function method infeasible). Previous work has also considered adversaries for KGs, but as part of training to improve their representation of the graph BIBREF37 , BIBREF38 . Adversarial Attack on KG Although this is the first work on adversarial attacks for link prediction, there are two approaches BIBREF39 , BIBREF17 that consider the task of adversarial attack on graphs. There are a few fundamental differences from our work: (1) they build their method on top of a path-based representations while we focus on embeddings, (2) they consider node classification as the target of their attacks while we attack link prediction, and (3) they conduct the attack on small graphs due to restricted scalability, while the complexity of our method does not depend on the size of the graph, but only the neighborhood, allowing us to attack real-world graphs."
|
| 89 |
+
],
|
| 90 |
+
[
|
| 91 |
+
"Motivated by the need to analyze the robustness and interpretability of link prediction models, we present a novel approach for conducting adversarial modifications to knowledge graphs. We introduce , completion robustness and interpretability via adversarial graph edits: identifying the fact to add into or remove from the KG that changes the prediction for a target fact. uses (1) an estimate of the score change for any target triple after adding or removing another fact, and (2) a gradient-based algorithm for identifying the most influential modification. We show that can effectively reduce ranking metrics on link prediction models upon applying the attack triples. Further, we incorporate the to study the interpretability of KG representations by summarizing the most influential facts for each relation. Finally, using , we introduce a novel automated error detection method for knowledge graphs. We have release the open-source implementation of our models at: https://pouyapez.github.io/criage."
|
| 92 |
+
],
|
| 93 |
+
[
|
| 94 |
+
"We would like to thank Matt Gardner, Marco Tulio Ribeiro, Zhengli Zhao, Robert L. Logan IV, Dheeru Dua and the anonymous reviewers for their detailed feedback and suggestions. This work is supported in part by Allen Institute for Artificial Intelligence (AI2) and in part by NSF awards #IIS-1817183 and #IIS-1756023. The views expressed are those of the authors and do not reflect the official policy or position of the funding agencies."
|
| 95 |
+
],
|
| 96 |
+
[
|
| 97 |
+
"We approximate the change on the score of the target triple upon applying attacks other than the $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ ones. Since each relation appears many times in the training triples, we can assume that applying a single attack will not considerably affect the relations embeddings. As a result, we just need to study the attacks in the form of $\\langle s, r^{\\prime }, o \\rangle $ and $\\langle s, r^{\\prime }, o^{\\prime } \\rangle $ . Defining the scoring function as $\\psi (s,r,o) = , ) \\cdot = _{s,r} \\cdot $ , we further assume that $\\psi (s,r,o) =\\cdot (, ) =\\cdot _{r,o}$ ."
|
| 98 |
+
],
|
| 99 |
+
[
|
| 100 |
+
"Using similar argument as the attacks in the form of $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ , we can calculate the effect of the attack, $\\overline{\\psi }{(s,r,o)}-\\psi (s, r, o)$ as: (s,r,o)-(s, r, o)=(-) s, r where $_{s, r} = (,)$ .",
|
| 101 |
+
"We now derive an efficient computation for $(-)$ . First, the derivative of the loss $(\\overline{G})= (G)+(\\langle s, r^{\\prime }, o^{\\prime } \\rangle )$ over $$ is: es (G) = es (G) - (1-) r', o' where $_{r^{\\prime }, o^{\\prime }} = (^{\\prime },^{\\prime })$ , and $\\varphi = \\sigma (\\psi (s,r^{\\prime },o^{\\prime }))$ . At convergence, after retraining, we expect $\\nabla _{e_s} (\\overline{G})=0$ . We perform first order Taylor approximation of $\\nabla _{e_s} (\\overline{G})$ to get: 0 - (1-)r',o'+",
|
| 102 |
+
"(Hs+(1-)r',o' r',o')(-) where $H_s$ is the $d\\times d$ Hessian matrix for $s$ , i.e. second order derivative of the loss w.r.t. $$ , computed sparsely. Solving for $-$ gives us: -=",
|
| 103 |
+
"(1-) (Hs + (1-) r',o'r',o')-1 r',o' In practice, $H_s$ is positive definite, making $H_s + \\varphi (1-\\varphi ) _{r^{\\prime },o^{\\prime }}^\\intercal _{r^{\\prime },o^{\\prime }}$ positive definite as well, and invertible. Then, we compute the score change as: (s,r,o)-(s, r, o)= r,o (-) =",
|
| 104 |
+
" ((1-) (Hs + (1-) r',o'r',o')-1 r',o')r,o."
|
| 105 |
+
],
|
| 106 |
+
[
|
| 107 |
+
"In this section we approximate the effect of attack in the form of $\\langle s, r^{\\prime }, o \\rangle $ . In contrast to $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ attacks, for this scenario we need to consider the change in the $$ , upon applying the attack, in approximation of the change in the score as well. Using previous results, we can approximate the $-$ as: -=",
|
| 108 |
+
"(1-) (Ho + (1-) s,r's,r')-1 s,r' and similarly, we can approximate $-$ as: -=",
|
| 109 |
+
" (1-) (Hs + (1-) r',or',o)-1 r',o where $H_s$ is the Hessian matrix over $$ . Then using these approximations: s,r(-) =",
|
| 110 |
+
" s,r ((1-) (Ho + (1-) s,r's,r')-1 s,r') and: (-) r,o=",
|
| 111 |
+
" ((1-) (Hs + (1-) r',or',o)-1 r',o) r,o and then calculate the change in the score as: (s,r,o)-(s, r, o)=",
|
| 112 |
+
" s,r.(-) +(-).r,o =",
|
| 113 |
+
" s,r ((1-) (Ho + (1-) s,r's,r')-1 s,r')+",
|
| 114 |
+
" ((1-) (Hs + (1-) r',or',o)-1 r',o) r, o"
|
| 115 |
+
],
|
| 116 |
+
[
|
| 117 |
+
"In here we derive the approximation of the change in the score upon applying an adversarial modification for TransE BIBREF18 . Using similar assumptions and parameters as before, to calculate the effect of the attack, $\\overline{\\psi }{(s,r,o)}$ (where $\\psi {(s,r,o)}=|+-|$ ), we need to compute $$ . To do so, we need to derive an efficient computation for $$ . First, the derivative of the loss $(\\overline{G})= (G)+(\\langle s^{\\prime }, r^{\\prime }, o \\rangle )$ over $$ is: eo (G) = eo (G) + (1-) s', r'-(s',r',o) where $_{s^{\\prime }, r^{\\prime }} = ^{\\prime }+ ^{\\prime }$ , and $\\varphi = \\sigma (\\psi (s^{\\prime },r^{\\prime },o))$ . At convergence, after retraining, we expect $\\nabla _{e_o} (\\overline{G})=0$ . We perform first order Taylor approximation of $\\nabla _{e_o} (\\overline{G})$ to get: 0",
|
| 118 |
+
" (1-) (s', r'-)(s',r',o)+(Ho - Hs',r',o)(-)",
|
| 119 |
+
" Hs',r',o = (1-)(s', r'-)(s', r'-)(s',r',o)2+",
|
| 120 |
+
" 1-(s',r',o)-(1-) (s', r'-)(s', r'-)(s',r',o)3 where $H_o$ is the $d\\times d$ Hessian matrix for $o$ , i.e., second order derivative of the loss w.r.t. $$ , computed sparsely. Solving for $$ gives us: = -(1-) (Ho - Hs',r',o)-1 (s', r'-)(s',r',o)",
|
| 121 |
+
" + Then, we compute the score change as: (s,r,o)= |+-|",
|
| 122 |
+
"= |++(1-) (Ho - Hs',r',o)-1",
|
| 123 |
+
" (s', r'-)(s',r',o) - |",
|
| 124 |
+
"Calculating this expression is efficient since $H_o$ is a $d\\times d$ matrix."
|
| 125 |
+
],
|
| 126 |
+
[
|
| 127 |
+
"In this section, we provide the output of the for some target triples. Sample adversarial attacks are provided in Table 5 . As it shows, attacks mostly try to change the type of the target triple's object by associating it with a subject and a relation that require a different entity types."
|
| 128 |
+
]
|
| 129 |
+
]
|
| 130 |
+
}
|
| 131 |
+
```
|
qasper-0148/instruction.md
ADDED
|
@@ -0,0 +1,131 @@
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|
| 1 |
+
Name of Paper: Investigating Robustness and Interpretability of Link Prediction via Adversarial Modifications
|
| 2 |
+
|
| 3 |
+
Question: How is this approach used to detect incorrect facts?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Background and Notation",
|
| 12 |
+
"Completion Robustness and Interpretability via Adversarial Graph Edits ()",
|
| 13 |
+
"Removing a fact ()",
|
| 14 |
+
"Adding a new fact ()",
|
| 15 |
+
"Challenges",
|
| 16 |
+
"Efficiently Identifying the Modification",
|
| 17 |
+
"First-order Approximation of Influence",
|
| 18 |
+
"Continuous Optimization for Search",
|
| 19 |
+
"Experiments",
|
| 20 |
+
"Influence Function vs ",
|
| 21 |
+
"Robustness of Link Prediction Models",
|
| 22 |
+
"Interpretability of Models",
|
| 23 |
+
"Finding Errors in Knowledge Graphs",
|
| 24 |
+
"Related Work",
|
| 25 |
+
"Conclusions",
|
| 26 |
+
"Acknowledgements",
|
| 27 |
+
"Appendix",
|
| 28 |
+
"Modifications of the Form \u2329s,r ' ,o ' \u232a\\langle s, r^{\\prime }, o^{\\prime } \\rangle ",
|
| 29 |
+
"Modifications of the Form \u2329s,r ' ,o\u232a\\langle s, r^{\\prime }, o \\rangle ",
|
| 30 |
+
"First-order Approximation of the Change For TransE",
|
| 31 |
+
"Sample Adversarial Attacks"
|
| 32 |
+
],
|
| 33 |
+
"paragraphs": [
|
| 34 |
+
[
|
| 35 |
+
"Knowledge graphs (KG) play a critical role in many real-world applications such as search, structured data management, recommendations, and question answering. Since KGs often suffer from incompleteness and noise in their facts (links), a number of recent techniques have proposed models that embed each entity and relation into a vector space, and use these embeddings to predict facts. These dense representation models for link prediction include tensor factorization BIBREF0 , BIBREF1 , BIBREF2 , algebraic operations BIBREF3 , BIBREF4 , BIBREF5 , multiple embeddings BIBREF6 , BIBREF7 , BIBREF8 , BIBREF9 , and complex neural models BIBREF10 , BIBREF11 . However, there are only a few studies BIBREF12 , BIBREF13 that investigate the quality of the different KG models. There is a need to go beyond just the accuracy on link prediction, and instead focus on whether these representations are robust and stable, and what facts they make use of for their predictions. In this paper, our goal is to design approaches that minimally change the graph structure such that the prediction of a target fact changes the most after the embeddings are relearned, which we collectively call Completion Robustness and Interpretability via Adversarial Graph Edits (). First, we consider perturbations that red!50!blackremove a neighboring link for the target fact, thus identifying the most influential related fact, providing an explanation for the model's prediction. As an example, consider the excerpt from a KG in Figure 1 with two observed facts, and a target predicted fact that Princes Henriette is the parent of Violante Bavaria. Our proposed graph perturbation, shown in Figure 1 , identifies the existing fact that Ferdinal Maria is the father of Violante Bavaria as the one when removed and model retrained, will change the prediction of Princes Henriette's child. We also study attacks that green!50!blackadd a new, fake fact into the KG to evaluate the robustness and sensitivity of link prediction models to small additions to the graph. An example attack for the original graph in Figure 1 , is depicted in Figure 1 . Such perturbations to the the training data are from a family of adversarial modifications that have been applied to other machine learning tasks, known as poisoning BIBREF14 , BIBREF15 , BIBREF16 , BIBREF17 .",
|
| 36 |
+
"Since the setting is quite different from traditional adversarial attacks, search for link prediction adversaries brings up unique challenges. To find these minimal changes for a target link, we need to identify the fact that, when added into or removed from the graph, will have the biggest impact on the predicted score of the target fact. Unfortunately, computing this change in the score is expensive since it involves retraining the model to recompute the embeddings. We propose an efficient estimate of this score change by approximating the change in the embeddings using Taylor expansion. The other challenge in identifying adversarial modifications for link prediction, especially when considering addition of fake facts, is the combinatorial search space over possible facts, which is intractable to enumerate. We introduce an inverter of the original embedding model, to decode the embeddings to their corresponding graph components, making the search of facts tractable by performing efficient gradient-based continuous optimization. We evaluate our proposed methods through following experiments. First, on relatively small KGs, we show that our approximations are accurate compared to the true change in the score. Second, we show that our additive attacks can effectively reduce the performance of state of the art models BIBREF2 , BIBREF10 up to $27.3\\%$ and $50.7\\%$ in Hits@1 for two large KGs: WN18 and YAGO3-10. We also explore the utility of adversarial modifications in explaining the model predictions by presenting rule-like descriptions of the most influential neighbors. Finally, we use adversaries to detect errors in the KG, obtaining up to $55\\%$ accuracy in detecting errors."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"In this section, we briefly introduce some notations, and existing relational embedding approaches that model knowledge graph completion using dense vectors. In KGs, facts are represented using triples of subject, relation, and object, $\\langle s, r, o\\rangle $ , where $s,o\\in \\xi $ , the set of entities, and $r\\in $ , the set of relations. To model the KG, a scoring function $\\psi :\\xi \\times \\times \\xi \\rightarrow $ is learned to evaluate whether any given fact is true. In this work, we focus on multiplicative models of link prediction, specifically DistMult BIBREF2 because of its simplicity and popularity, and ConvE BIBREF10 because of its high accuracy. We can represent the scoring function of such methods as $\\psi (s,r,o) = , ) \\cdot $ , where $,,\\in ^d$ are embeddings of the subject, relation, and object respectively. In DistMult, $, ) = \\odot $ , where $\\odot $ is element-wise multiplication operator. Similarly, in ConvE, $, )$ is computed by a convolution on the concatenation of $$ and $s,o\\in \\xi $0 .",
|
| 40 |
+
"We use the same setup as BIBREF10 for training, i.e., incorporate binary cross-entropy loss over the triple scores. In particular, for subject-relation pairs $(s,r)$ in the training data $G$ , we use binary $y^{s,r}_o$ to represent negative and positive facts. Using the model's probability of truth as $\\sigma (\\psi (s,r,o))$ for $\\langle s,r,o\\rangle $ , the loss is defined as: (G) = (s,r)o ys,ro(((s,r,o)))",
|
| 41 |
+
"+ (1-ys,ro)(1 - ((s,r,o))). Gradient descent is used to learn the embeddings $,,$ , and the parameters of $, if any.\n$ "
|
| 42 |
+
],
|
| 43 |
+
[
|
| 44 |
+
"For adversarial modifications on KGs, we first define the space of possible modifications. For a target triple $\\langle s, r, o\\rangle $ , we constrain the possible triples that we can remove (or inject) to be in the form of $\\langle s^{\\prime }, r^{\\prime }, o\\rangle $ i.e $s^{\\prime }$ and $r^{\\prime }$ may be different from the target, but the object is not. We analyze other forms of modifications such as $\\langle s, r^{\\prime }, o^{\\prime }\\rangle $ and $\\langle s, r^{\\prime }, o\\rangle $ in appendices \"Modifications of the Form \u2329s,r ' ,o ' \u232a\\langle s, r^{\\prime }, o^{\\prime } \\rangle \" and \"Modifications of the Form \u2329s,r ' ,o\u232a\\langle s, r^{\\prime }, o \\rangle \" , and leave empirical evaluation of these modifications for future work."
|
| 45 |
+
],
|
| 46 |
+
[
|
| 47 |
+
"For explaining a target prediction, we are interested in identifying the observed fact that has the most influence (according to the model) on the prediction. We define influence of an observed fact on the prediction as the change in the prediction score if the observed fact was not present when the embeddings were learned. Previous work have used this concept of influence similarly for several different tasks BIBREF19 , BIBREF20 . Formally, for the target triple ${s,r,o}$ and observed graph $G$ , we want to identify a neighboring triple ${s^{\\prime },r^{\\prime },o}\\in G$ such that the score $\\psi (s,r,o)$ when trained on $G$ and the score $\\overline{\\psi }(s,r,o)$ when trained on $G-\\lbrace {s^{\\prime },r^{\\prime },o}\\rbrace $ are maximally different, i.e. *argmax(s', r')Nei(o) (s',r')(s,r,o) where $\\Delta _{(s^{\\prime },r^{\\prime })}(s,r,o)=\\psi (s, r, o)-\\overline{\\psi }(s,r,o)$ , and $\\text{Nei}(o)=\\lbrace (s^{\\prime },r^{\\prime })|\\langle s^{\\prime },r^{\\prime },o \\rangle \\in G \\rbrace $ ."
|
| 48 |
+
],
|
| 49 |
+
[
|
| 50 |
+
"We are also interested in investigating the robustness of models, i.e., how sensitive are the predictions to small additions to the knowledge graph. Specifically, for a target prediction ${s,r,o}$ , we are interested in identifying a single fake fact ${s^{\\prime },r^{\\prime },o}$ that, when added to the knowledge graph $G$ , changes the prediction score $\\psi (s,r,o)$ the most. Using $\\overline{\\psi }(s,r,o)$ as the score after training on $G\\cup \\lbrace {s^{\\prime },r^{\\prime },o}\\rbrace $ , we define the adversary as: *argmax(s', r') (s',r')(s,r,o) where $\\Delta _{(s^{\\prime },r^{\\prime })}(s,r,o)=\\psi (s, r, o)-\\overline{\\psi }(s,r,o)$ . The search here is over any possible $s^{\\prime }\\in \\xi $ , which is often in the millions for most real-world KGs, and $r^{\\prime }\\in $ . We also identify adversaries that increase the prediction score for specific false triple, i.e., for a target fake fact ${s,r,o}$ , the adversary is ${s^{\\prime },r^{\\prime },o}$0 , where ${s^{\\prime },r^{\\prime },o}$1 is defined as before."
|
| 51 |
+
],
|
| 52 |
+
[
|
| 53 |
+
"There are a number of crucial challenges when conducting such adversarial attack on KGs. First, evaluating the effect of changing the KG on the score of the target fact ( $\\overline{\\psi }(s,r,o)$ ) is expensive since we need to update the embeddings by retraining the model on the new graph; a very time-consuming process that is at least linear in the size of $G$ . Second, since there are many candidate facts that can be added to the knowledge graph, identifying the most promising adversary through search-based methods is also expensive. Specifically, the search size for unobserved facts is $|\\xi | \\times ||$ , which, for example in YAGO3-10 KG, can be as many as $4.5 M$ possible facts for a single target prediction."
|
| 54 |
+
],
|
| 55 |
+
[
|
| 56 |
+
"In this section, we propose algorithms to address mentioned challenges by (1) approximating the effect of changing the graph on a target prediction, and (2) using continuous optimization for the discrete search over potential modifications."
|
| 57 |
+
],
|
| 58 |
+
[
|
| 59 |
+
"We first study the addition of a fact to the graph, and then extend it to cover removal as well. To capture the effect of an adversarial modification on the score of a target triple, we need to study the effect of the change on the vector representations of the target triple. We use $$ , $$ , and $$ to denote the embeddings of $s,r,o$ at the solution of $\\operatornamewithlimits{argmin} (G)$ , and when considering the adversarial triple $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ , we use $$ , $$ , and $$ for the new embeddings of $s,r,o$ , respectively. Thus $$0 is a solution to $$1 , which can also be written as $$2 . Similarly, $$3 s', r', o $$4 $$5 $$6 $$7 o $$8 $$9 $$0 $$1 $$2 $$3 O(n3) $$4 $$5 $$6 (s,r,o)-(s, r, o) $$7 - $$8 s, r = ,) $$9 - $s,r,o$0 (G)= (G)+(s', r', o ) $s,r,o$1 $s,r,o$2 s', r' = ',') $s,r,o$3 = ((s',r',o)) $s,r,o$4 eo (G)=0 $s,r,o$5 eo (G) $s,r,o$6 Ho $s,r,o$7 dd $s,r,o$8 o $s,r,o$9 $\\operatornamewithlimits{argmin} (G)$0 - $\\operatornamewithlimits{argmin} (G)$1 -= $\\operatornamewithlimits{argmin} (G)$2 Ho $\\operatornamewithlimits{argmin} (G)$3 Ho + (1-) s',r's',r' $\\operatornamewithlimits{argmin} (G)$4 Ho $\\operatornamewithlimits{argmin} (G)$5 dd $\\operatornamewithlimits{argmin} (G)$6 d $\\operatornamewithlimits{argmin} (G)$7 s,r,s',r'd $\\operatornamewithlimits{argmin} (G)$8 s, r, o $\\operatornamewithlimits{argmin} (G)$9 s', r', o $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $0 $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $1 $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $2 "
|
| 60 |
+
],
|
| 61 |
+
[
|
| 62 |
+
"Using the approximations provided in the previous section, Eq. () and (), we can use brute force enumeration to find the adversary $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ . This approach is feasible when removing an observed triple since the search space of such modifications is usually small; it is the number of observed facts that share the object with the target. On the other hand, finding the most influential unobserved fact to add requires search over a much larger space of all possible unobserved facts (that share the object). Instead, we identify the most influential unobserved fact $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ by using a gradient-based algorithm on vector $_{s^{\\prime },r^{\\prime }}$ in the embedding space (reminder, $_{s^{\\prime },r^{\\prime }}=^{\\prime },^{\\prime })$ ), solving the following continuous optimization problem in $^d$ : *argmaxs', r' (s',r')(s,r,o). After identifying the optimal $_{s^{\\prime }, r^{\\prime }}$ , we still need to generate the pair $(s^{\\prime },r^{\\prime })$ . We design a network, shown in Figure 2 , that maps the vector $_{s^{\\prime },r^{\\prime }}$ to the entity-relation space, i.e., translating it into $(s^{\\prime },r^{\\prime })$ . In particular, we train an auto-encoder where the encoder is fixed to receive the $s$ and $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $0 as one-hot inputs, and calculates $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $1 in the same way as the DistMult and ConvE encoders respectively (using trained embeddings). The decoder is trained to take $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $2 as input and produce $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $3 and $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $4 , essentially inverting $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $5 s, r $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $6 s $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $7 r $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $8 s, r $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $9 We evaluate the performance of our inverter networks (one for each model/dataset) on correctly recovering the pairs of subject and relation from the test set of our benchmarks, given the $_{s^{\\prime },r^{\\prime }}$0 . The accuracy of recovered pairs (and of each argument) is given in Table 1 . As shown, our networks achieve a very high accuracy, demonstrating their ability to invert vectors $_{s^{\\prime },r^{\\prime }}$1 to $_{s^{\\prime },r^{\\prime }}$2 pairs."
|
| 63 |
+
],
|
| 64 |
+
[
|
| 65 |
+
"We evaluate by ( \"Influence Function vs \" ) comparing estimate with the actual effect of the attacks, ( \"Robustness of Link Prediction Models\" ) studying the effect of adversarial attacks on evaluation metrics, ( \"Interpretability of Models\" ) exploring its application to the interpretability of KG representations, and ( \"Finding Errors in Knowledge Graphs\" ) detecting incorrect triples."
|
| 66 |
+
],
|
| 67 |
+
[
|
| 68 |
+
"To evaluate the quality of our approximations and compare with influence function (IF), we conduct leave one out experiments. In this setup, we take all the neighbors of a random target triple as candidate modifications, remove them one at a time, retrain the model each time, and compute the exact change in the score of the target triple. We can use the magnitude of this change in score to rank the candidate triples, and compare this exact ranking with ranking as predicted by: , influence function with and without Hessian matrix, and the original model score (with the intuition that facts that the model is most confident of will have the largest impact when removed). Similarly, we evaluate by considering 200 random triples that share the object entity with the target sample as candidates, and rank them as above. The average results of Spearman's $\\rho $ and Kendall's $\\tau $ rank correlation coefficients over 10 random target samples is provided in Table 3 . performs comparably to the influence function, confirming that our approximation is accurate. Influence function is slightly more accurate because they use the complete Hessian matrix over all the parameters, while we only approximate the change by calculating the Hessian over $$ . The effect of this difference on scalability is dramatic, constraining IF to very small graphs and small embedding dimensionality ( $d\\le 10$ ) before we run out of memory. In Figure 3 , we show the time to compute a single adversary by IF compared to , as we steadily grow the number of entities (randomly chosen subgraphs), averaged over 10 random triples. As it shows, is mostly unaffected by the number of entities while IF increases quadratically. Considering that real-world KGs have tens of thousands of times more entities, making IF unfeasible for them."
|
| 69 |
+
],
|
| 70 |
+
[
|
| 71 |
+
"Now we evaluate the effectiveness of to successfully attack link prediction by adding false facts. The goal here is to identify the attacks for triples in the test data, and measuring their effect on MRR and Hits@ metrics (ranking evaluations) after conducting the attack and retraining the model.",
|
| 72 |
+
"Since this is the first work on adversarial attacks for link prediction, we introduce several baselines to compare against our method. For finding the adversarial fact to add for the target triple $\\langle s, r, o \\rangle $ , we consider two baselines: 1) choosing a random fake fact $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ (Random Attack); 2) finding $(s^{\\prime }, r^{\\prime })$ by first calculating $, )$ and then feeding $-, )$ to the decoder of the inverter function (Opposite Attack). In addition to , we introduce two other alternatives of our method: (1) , that uses to increase the score of fake fact over a test triple, i.e., we find the fake fact the model ranks second after the test triple, and identify the adversary for them, and (2) that selects between and attacks based on which has a higher estimated change in score.",
|
| 73 |
+
"All-Test The result of the attack on all test facts as targets is provided in the Table 4 . outperforms the baselines, demonstrating its ability to effectively attack the KG representations. It seems DistMult is more robust against random attacks, while ConvE is more robust against designed attacks. is more effective than since changing the score of a fake fact is easier than of actual facts; there is no existing evidence to support fake facts. We also see that YAGO3-10 models are more robust than those for WN18. Looking at sample attacks (provided in Appendix \"Sample Adversarial Attacks\" ), mostly tries to change the type of the target object by associating it with a subject and a relation for a different entity type.",
|
| 74 |
+
"Uncertain-Test To better understand the effect of attacks, we consider a subset of test triples that 1) the model predicts correctly, 2) difference between their scores and the negative sample with the highest score is minimum. This \u201cUncertain-Test\u201d subset contains 100 triples from each of the original test sets, and we provide results of attacks on this data in Table 4 . The attacks are much more effective in this scenario, causing a considerable drop in the metrics. Further, in addition to significantly outperforming other baselines, they indicate that ConvE's confidence is much more robust.",
|
| 75 |
+
"Relation Breakdown We perform additional analysis on the YAGO3-10 dataset to gain a deeper understanding of the performance of our model. As shown in Figure 4 , both DistMult and ConvE provide a more robust representation for isAffiliatedTo and isConnectedTo relations, demonstrating the confidence of models in identifying them. Moreover, the affects DistMult more in playsFor and isMarriedTo relations while affecting ConvE more in isConnectedTo relations.",
|
| 76 |
+
"Examples Sample adversarial attacks are provided in Table 5 . attacks mostly try to change the type of the target triple's object by associating it with a subject and a relation that require a different entity types."
|
| 77 |
+
],
|
| 78 |
+
[
|
| 79 |
+
"To be able to understand and interpret why a link is predicted using the opaque, dense embeddings, we need to find out which part of the graph was most influential on the prediction. To provide such explanations for each predictions, we identify the most influential fact using . Instead of focusing on individual predictions, we aggregate the explanations over the whole dataset for each relation using a simple rule extraction technique: we find simple patterns on subgraphs that surround the target triple and the removed fact from , and appear more than $90\\%$ of the time. We only focus on extracting length-2 horn rules, i.e., $R_1(a,c)\\wedge R_2(c,b)\\Rightarrow R(a,b)$ , where $R(a,b)$ is the target and $R_2(c,b)$ is the removed fact. Table 6 shows extracted YAGO3-10 rules that are common to both models, and ones that are not. The rules show several interesting inferences, such that hasChild is often inferred via married parents, and isLocatedIn via transitivity. There are several differences in how the models reason as well; DistMult often uses the hasCapital as an intermediate step for isLocatedIn, while ConvE incorrectly uses isNeighbor. We also compare against rules extracted by BIBREF2 for YAGO3-10 that utilizes the structure of DistMult: they require domain knowledge on types and cannot be applied to ConvE. Interestingly, the extracted rules contain all the rules provided by , demonstrating that can be used to accurately interpret models, including ones that are not interpretable, such as ConvE. These are preliminary steps toward interpretability of link prediction models, and we leave more analysis of interpretability to future work."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"Here, we demonstrate another potential use of adversarial modifications: finding erroneous triples in the knowledge graph. Intuitively, if there is an error in the graph, the triple is likely to be inconsistent with its neighborhood, and thus the model should put least trust on this triple. In other words, the error triple should have the least influence on the model's prediction of the training data. Formally, to find the incorrect triple $\\langle s^{\\prime }, r^{\\prime }, o\\rangle $ in the neighborhood of the train triple $\\langle s, r, o\\rangle $ , we need to find the triple $\\langle s^{\\prime },r^{\\prime },o\\rangle $ that results in the least change $\\Delta _{(s^{\\prime },r^{\\prime })}(s,r,o)$ when removed from the graph.",
|
| 83 |
+
"To evaluate this application, we inject random triples into the graph, and measure the ability of to detect the errors using our optimization. We consider two types of incorrect triples: 1) incorrect triples in the form of $\\langle s^{\\prime }, r, o\\rangle $ where $s^{\\prime }$ is chosen randomly from all of the entities, and 2) incorrect triples in the form of $\\langle s^{\\prime }, r^{\\prime }, o\\rangle $ where $s^{\\prime }$ and $r^{\\prime }$ are chosen randomly. We choose 100 random triples from the observed graph, and for each of them, add an incorrect triple (in each of the two scenarios) to its neighborhood. Then, after retraining DistMult on this noisy training data, we identify error triples through a search over the neighbors of the 100 facts. The result of choosing the neighbor with the least influence on the target is provided in the Table 7 . When compared with baselines that randomly choose one of the neighbors, or assume that the fact with the lowest score is incorrect, we see that outperforms both of these with a considerable gap, obtaining an accuracy of $42\\%$ and $55\\%$ in detecting errors."
|
| 84 |
+
],
|
| 85 |
+
[
|
| 86 |
+
"Learning relational knowledge representations has been a focus of active research in the past few years, but to the best of our knowledge, this is the first work on conducting adversarial modifications on the link prediction task. Knowledge graph embedding There is a rich literature on representing knowledge graphs in vector spaces that differ in their scoring functions BIBREF21 , BIBREF22 , BIBREF23 . Although is primarily applicable to multiplicative scoring functions BIBREF0 , BIBREF1 , BIBREF2 , BIBREF24 , these ideas apply to additive scoring functions BIBREF18 , BIBREF6 , BIBREF7 , BIBREF25 as well, as we show in Appendix \"First-order Approximation of the Change For TransE\" .",
|
| 87 |
+
"Furthermore, there is a growing body of literature that incorporates an extra types of evidence for more informed embeddings such as numerical values BIBREF26 , images BIBREF27 , text BIBREF28 , BIBREF29 , BIBREF30 , and their combinations BIBREF31 . Using , we can gain a deeper understanding of these methods, especially those that build their embeddings wit hmultiplicative scoring functions.",
|
| 88 |
+
"Interpretability and Adversarial Modification There has been a significant recent interest in conducting an adversarial attacks on different machine learning models BIBREF16 , BIBREF32 , BIBREF33 , BIBREF34 , BIBREF35 , BIBREF36 to attain the interpretability, and further, evaluate the robustness of those models. BIBREF20 uses influence function to provide an approach to understanding black-box models by studying the changes in the loss occurring as a result of changes in the training data. In addition to incorporating their established method on KGs, we derive a novel approach that differs from their procedure in two ways: (1) instead of changes in the loss, we consider the changes in the scoring function, which is more appropriate for KG representations, and (2) in addition to searching for an attack, we introduce a gradient-based method that is much faster, especially for \u201cadding an attack triple\u201d (the size of search space make the influence function method infeasible). Previous work has also considered adversaries for KGs, but as part of training to improve their representation of the graph BIBREF37 , BIBREF38 . Adversarial Attack on KG Although this is the first work on adversarial attacks for link prediction, there are two approaches BIBREF39 , BIBREF17 that consider the task of adversarial attack on graphs. There are a few fundamental differences from our work: (1) they build their method on top of a path-based representations while we focus on embeddings, (2) they consider node classification as the target of their attacks while we attack link prediction, and (3) they conduct the attack on small graphs due to restricted scalability, while the complexity of our method does not depend on the size of the graph, but only the neighborhood, allowing us to attack real-world graphs."
|
| 89 |
+
],
|
| 90 |
+
[
|
| 91 |
+
"Motivated by the need to analyze the robustness and interpretability of link prediction models, we present a novel approach for conducting adversarial modifications to knowledge graphs. We introduce , completion robustness and interpretability via adversarial graph edits: identifying the fact to add into or remove from the KG that changes the prediction for a target fact. uses (1) an estimate of the score change for any target triple after adding or removing another fact, and (2) a gradient-based algorithm for identifying the most influential modification. We show that can effectively reduce ranking metrics on link prediction models upon applying the attack triples. Further, we incorporate the to study the interpretability of KG representations by summarizing the most influential facts for each relation. Finally, using , we introduce a novel automated error detection method for knowledge graphs. We have release the open-source implementation of our models at: https://pouyapez.github.io/criage."
|
| 92 |
+
],
|
| 93 |
+
[
|
| 94 |
+
"We would like to thank Matt Gardner, Marco Tulio Ribeiro, Zhengli Zhao, Robert L. Logan IV, Dheeru Dua and the anonymous reviewers for their detailed feedback and suggestions. This work is supported in part by Allen Institute for Artificial Intelligence (AI2) and in part by NSF awards #IIS-1817183 and #IIS-1756023. The views expressed are those of the authors and do not reflect the official policy or position of the funding agencies."
|
| 95 |
+
],
|
| 96 |
+
[
|
| 97 |
+
"We approximate the change on the score of the target triple upon applying attacks other than the $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ ones. Since each relation appears many times in the training triples, we can assume that applying a single attack will not considerably affect the relations embeddings. As a result, we just need to study the attacks in the form of $\\langle s, r^{\\prime }, o \\rangle $ and $\\langle s, r^{\\prime }, o^{\\prime } \\rangle $ . Defining the scoring function as $\\psi (s,r,o) = , ) \\cdot = _{s,r} \\cdot $ , we further assume that $\\psi (s,r,o) =\\cdot (, ) =\\cdot _{r,o}$ ."
|
| 98 |
+
],
|
| 99 |
+
[
|
| 100 |
+
"Using similar argument as the attacks in the form of $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ , we can calculate the effect of the attack, $\\overline{\\psi }{(s,r,o)}-\\psi (s, r, o)$ as: (s,r,o)-(s, r, o)=(-) s, r where $_{s, r} = (,)$ .",
|
| 101 |
+
"We now derive an efficient computation for $(-)$ . First, the derivative of the loss $(\\overline{G})= (G)+(\\langle s, r^{\\prime }, o^{\\prime } \\rangle )$ over $$ is: es (G) = es (G) - (1-) r', o' where $_{r^{\\prime }, o^{\\prime }} = (^{\\prime },^{\\prime })$ , and $\\varphi = \\sigma (\\psi (s,r^{\\prime },o^{\\prime }))$ . At convergence, after retraining, we expect $\\nabla _{e_s} (\\overline{G})=0$ . We perform first order Taylor approximation of $\\nabla _{e_s} (\\overline{G})$ to get: 0 - (1-)r',o'+",
|
| 102 |
+
"(Hs+(1-)r',o' r',o')(-) where $H_s$ is the $d\\times d$ Hessian matrix for $s$ , i.e. second order derivative of the loss w.r.t. $$ , computed sparsely. Solving for $-$ gives us: -=",
|
| 103 |
+
"(1-) (Hs + (1-) r',o'r',o')-1 r',o' In practice, $H_s$ is positive definite, making $H_s + \\varphi (1-\\varphi ) _{r^{\\prime },o^{\\prime }}^\\intercal _{r^{\\prime },o^{\\prime }}$ positive definite as well, and invertible. Then, we compute the score change as: (s,r,o)-(s, r, o)= r,o (-) =",
|
| 104 |
+
" ((1-) (Hs + (1-) r',o'r',o')-1 r',o')r,o."
|
| 105 |
+
],
|
| 106 |
+
[
|
| 107 |
+
"In this section we approximate the effect of attack in the form of $\\langle s, r^{\\prime }, o \\rangle $ . In contrast to $\\langle s^{\\prime }, r^{\\prime }, o \\rangle $ attacks, for this scenario we need to consider the change in the $$ , upon applying the attack, in approximation of the change in the score as well. Using previous results, we can approximate the $-$ as: -=",
|
| 108 |
+
"(1-) (Ho + (1-) s,r's,r')-1 s,r' and similarly, we can approximate $-$ as: -=",
|
| 109 |
+
" (1-) (Hs + (1-) r',or',o)-1 r',o where $H_s$ is the Hessian matrix over $$ . Then using these approximations: s,r(-) =",
|
| 110 |
+
" s,r ((1-) (Ho + (1-) s,r's,r')-1 s,r') and: (-) r,o=",
|
| 111 |
+
" ((1-) (Hs + (1-) r',or',o)-1 r',o) r,o and then calculate the change in the score as: (s,r,o)-(s, r, o)=",
|
| 112 |
+
" s,r.(-) +(-).r,o =",
|
| 113 |
+
" s,r ((1-) (Ho + (1-) s,r's,r')-1 s,r')+",
|
| 114 |
+
" ((1-) (Hs + (1-) r',or',o)-1 r',o) r, o"
|
| 115 |
+
],
|
| 116 |
+
[
|
| 117 |
+
"In here we derive the approximation of the change in the score upon applying an adversarial modification for TransE BIBREF18 . Using similar assumptions and parameters as before, to calculate the effect of the attack, $\\overline{\\psi }{(s,r,o)}$ (where $\\psi {(s,r,o)}=|+-|$ ), we need to compute $$ . To do so, we need to derive an efficient computation for $$ . First, the derivative of the loss $(\\overline{G})= (G)+(\\langle s^{\\prime }, r^{\\prime }, o \\rangle )$ over $$ is: eo (G) = eo (G) + (1-) s', r'-(s',r',o) where $_{s^{\\prime }, r^{\\prime }} = ^{\\prime }+ ^{\\prime }$ , and $\\varphi = \\sigma (\\psi (s^{\\prime },r^{\\prime },o))$ . At convergence, after retraining, we expect $\\nabla _{e_o} (\\overline{G})=0$ . We perform first order Taylor approximation of $\\nabla _{e_o} (\\overline{G})$ to get: 0",
|
| 118 |
+
" (1-) (s', r'-)(s',r',o)+(Ho - Hs',r',o)(-)",
|
| 119 |
+
" Hs',r',o = (1-)(s', r'-)(s', r'-)(s',r',o)2+",
|
| 120 |
+
" 1-(s',r',o)-(1-) (s', r'-)(s', r'-)(s',r',o)3 where $H_o$ is the $d\\times d$ Hessian matrix for $o$ , i.e., second order derivative of the loss w.r.t. $$ , computed sparsely. Solving for $$ gives us: = -(1-) (Ho - Hs',r',o)-1 (s', r'-)(s',r',o)",
|
| 121 |
+
" + Then, we compute the score change as: (s,r,o)= |+-|",
|
| 122 |
+
"= |++(1-) (Ho - Hs',r',o)-1",
|
| 123 |
+
" (s', r'-)(s',r',o) - |",
|
| 124 |
+
"Calculating this expression is efficient since $H_o$ is a $d\\times d$ matrix."
|
| 125 |
+
],
|
| 126 |
+
[
|
| 127 |
+
"In this section, we provide the output of the for some target triples. Sample adversarial attacks are provided in Table 5 . As it shows, attacks mostly try to change the type of the target triple's object by associating it with a subject and a relation that require a different entity types."
|
| 128 |
+
]
|
| 129 |
+
]
|
| 130 |
+
}
|
| 131 |
+
```
|
qasper-0149/instruction.md
ADDED
|
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|
|
|
|
|
|
|
|
|
|
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|
|
| 1 |
+
Name of Paper: Investigating Robustness and Interpretability of Link Prediction via Adversarial Modifications
|
| 2 |
+
|
| 3 |
+
Question: Can this adversarial approach be used to directly improve model accuracy?
|
qasper-0156/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: BERTRAM: Improved Word Embeddings Have Big Impact on Contextualized Model Performance
|
| 2 |
+
|
| 3 |
+
Question: What models other than standalone BERT is new model compared to?
|
qasper-0158/instruction.md
ADDED
|
@@ -0,0 +1,123 @@
|
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|
|
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|
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|
|
|
|
| 1 |
+
Name of Paper: BERTRAM: Improved Word Embeddings Have Big Impact on Contextualized Model Performance
|
| 2 |
+
|
| 3 |
+
Question: What are three downstream task datasets?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Related Work",
|
| 12 |
+
"Model ::: Form-Context Model",
|
| 13 |
+
"Model ::: Bertram",
|
| 14 |
+
"Model ::: Training",
|
| 15 |
+
"Generation of Rare Word Datasets",
|
| 16 |
+
"Generation of Rare Word Datasets ::: Dataset Splitting",
|
| 17 |
+
"Generation of Rare Word Datasets ::: Baseline Training",
|
| 18 |
+
"Generation of Rare Word Datasets ::: Test Set Generation",
|
| 19 |
+
"Evaluation ::: Setup",
|
| 20 |
+
"Evaluation ::: WNLaMPro",
|
| 21 |
+
"Evaluation ::: Downstream Task Datasets",
|
| 22 |
+
"Conclusion"
|
| 23 |
+
],
|
| 24 |
+
"paragraphs": [
|
| 25 |
+
[
|
| 26 |
+
"As traditional word embedding algorithms BIBREF1 are known to struggle with rare words, several techniques for improving their representations have been proposed over the last few years. These approaches exploit either the contexts in which rare words occur BIBREF2, BIBREF3, BIBREF4, BIBREF5, their surface-form BIBREF6, BIBREF7, BIBREF8, or both BIBREF9, BIBREF10. However, all of these approaches are designed for and evaluated on uncontextualized word embeddings.",
|
| 27 |
+
"With the recent shift towards contextualized representations obtained from pretrained deep language models BIBREF11, BIBREF12, BIBREF13, BIBREF14, the question naturally arises whether these approaches are facing the same problem. As all of them already handle rare words implicitly \u2013 using methods such as byte-pair encoding BIBREF15 and WordPiece embeddings BIBREF16, or even character-level CNNs BIBREF17 \u2013, it is unclear whether these models even require special treatment of rare words. However, the listed methods only make use of surface-form information, whereas BIBREF9 found that for covering a wide range of rare words, it is crucial to consider both surface-form and contexts.",
|
| 28 |
+
"Consistently, BIBREF0 recently showed that for BERT BIBREF13, a popular pretrained language model based on a Transformer architecture BIBREF18, performance on a rare word probing task can significantly be improve by relearning representations of rare words using Attentive Mimicking BIBREF19. However, their proposed model is limited in two important respects:",
|
| 29 |
+
"For processing contexts, it uses a simple bag-of-words model, throwing away much of the available information.",
|
| 30 |
+
"It combines form and context only in a shallow fashion, thus preventing both input signals from sharing information in any sophisticated manner.",
|
| 31 |
+
"Importantly, this limitation applies not only to their model, but to all previous work on obtaining representations for rare words by leveraging form and context. While using bag-of-words models is a reasonable choice for uncontextualized embeddings, which are often themselves based on such models BIBREF1, BIBREF7, it stands to reason that they are suboptimal for contextualized embeddings based on position-aware deep neural architectures.",
|
| 32 |
+
"To overcome these limitations, we introduce Bertram (BERT for Attentive Mimicking), a novel architecture for understanding rare words that combines a pretrained BERT language model with Attentive Mimicking BIBREF19. Unlike previous approaches making use of language models BIBREF5, our approach integrates BERT in an end-to-end fashion and directly makes use of its hidden states. By giving Bertram access to both surface form and context information already at its very lowest layer, we allow for a deep connection and exchange of information between both input signals.",
|
| 33 |
+
"For various reasons, assessing the effectiveness of methods like Bertram in a contextualized setting poses a huge difficulty: While most previous work on rare words was evaluated on datasets explicitly focusing on such words BIBREF6, BIBREF3, BIBREF4, BIBREF5, BIBREF10, all of these datasets are tailored towards context-independent embeddings and thus not suitable for evaluating our proposed model. Furthermore, understanding rare words is of negligible importance for most commonly used downstream task datasets. To evaluate our proposed model, we therefore introduce a novel procedure that allows us to automatically turn arbitrary text classification datasets into ones where rare words are guaranteed to be important. This is achieved by replacing classification-relevant frequent words with rare synonyms obtained using semantic resources such as WordNet BIBREF20.",
|
| 34 |
+
"Using this procedure, we extract rare word datasets from three commonly used text (or text pair) classification datasets: MNLI BIBREF21, AG's News BIBREF22 and DBPedia BIBREF23. On both the WNLaMPro dataset of BIBREF0 and all three so-obtained datasets, our proposed Bertram model outperforms previous work by a large margin.",
|
| 35 |
+
"In summary, our contributions are as follows:",
|
| 36 |
+
"We show that a pretrained BERT instance can be integrated into Attentive Mimicking, resulting in much better context representations and a deeper connection of form and context.",
|
| 37 |
+
"We design a procedure that allows us to automatically transform text classification datasets into datasets for which rare words are guaranteed to be important.",
|
| 38 |
+
"We show that Bertram achieves a new state-of-the-art on the WNLaMPro probing task BIBREF0 and beats all baselines on rare word instances of AG's News, MNLI and DBPedia, resulting in an absolute improvement of up to 24% over a BERT baseline."
|
| 39 |
+
],
|
| 40 |
+
[
|
| 41 |
+
"Incorporating surface-form information (e.g., morphemes, characters or character $n$-grams) is a commonly used technique for improving word representations. For context-independent word embeddings, this information can either be injected into a given embedding space BIBREF6, BIBREF8, or a model can directly be given access to it during training BIBREF7, BIBREF24, BIBREF25. In the area of contextualized representations, many architectures employ subword segmentation methods BIBREF12, BIBREF13, BIBREF26, BIBREF14, whereas others use convolutional neural networks to directly access character-level information BIBREF27, BIBREF11, BIBREF17.",
|
| 42 |
+
"Complementary to surface form, another useful source of information for understanding rare words are the contexts in which they occur BIBREF2, BIBREF3, BIBREF4. As recently shown by BIBREF19, BIBREF9, combining form and context leads to significantly better results than using just one of both input signals for a wide range of tasks. While all aforementioned methods are based on simple bag-of-words models, BIBREF5 recently proposed an architecture based on the context2vec language model BIBREF28. However, in contrast to our work, they (i) do not incorporate surface-form information and (ii) do not directly access the hidden states of the language model, but instead simply use its output distribution.",
|
| 43 |
+
"There are several datasets explicitly focusing on rare words, e.g. the Stanford Rare Word dataset of BIBREF6, the Definitional Nonce dataset of BIBREF3 and the Contextual Rare Word dataset BIBREF4. However, all of these datasets are only suitable for evaluating context-independent word representations.",
|
| 44 |
+
"Our proposed method of generating rare word datasets is loosely related to adversarial example generation methods such as HotFlip BIBREF29, which manipulate the input to change a model's prediction. We use a similar mechanism to determine which words in a given sentence are most important and replace these words with rare synonyms."
|
| 45 |
+
],
|
| 46 |
+
[
|
| 47 |
+
"We review the architecture of the form-context model (FCM) BIBREF9, which forms the basis for our model. Given a set of $d$-dimensional high-quality embeddings for frequent words, FCM can be used to induce embeddings for infrequent words that are appropriate for the given embedding space. This is done as follows: Given a word $w$ and a context $C$ in which it occurs, a surface-form embedding $v_{(w,{C})}^\\text{form} \\in \\mathbb {R}^d$ is obtained similar to BIBREF7 by averaging over embeddings of all $n$-grams in $w$; these $n$-gram embeddings are learned during training. Similarly, a context embedding $v_{(w,{C})}^\\text{context} \\in \\mathbb {R}^d$ is obtained by averaging over the embeddings of all words in $C$. The so-obtained form and context embeddings are then combined using a gate",
|
| 48 |
+
"with parameters $w \\in \\mathbb {R}^{2d}, b \\in \\mathbb {R}$ and $\\sigma $ denoting the sigmoid function, allowing the model to decide for each pair $(x,y)$ of form and context embeddings how much attention should be paid to $x$ and $y$, respectively.",
|
| 49 |
+
"The final representation of $w$ is then simply a weighted sum of form and context embeddings:",
|
| 50 |
+
"where $\\alpha = g(v_{(w,C)}^\\text{form}, v_{(w,C)}^\\text{context})$ and $A$ is a $d\\times d$ matrix that is learned during training.",
|
| 51 |
+
"While the context-part of FCM is able to capture the broad topic of numerous rare words, in many cases it is not able to obtain a more concrete and detailed understanding thereof BIBREF9. This is hardly surprising given the model's simplicity; it does, for example, make no use at all of the relative positions of context words. Furthermore, the simple gating mechanism results in only a shallow combination of form and context. That is, the model is not able to combine form and context until the very last step: While it can choose how much to attend to form and context, respectively, the corresponding embeddings do not share any information and thus cannot influence each other in any way."
|
| 52 |
+
],
|
| 53 |
+
[
|
| 54 |
+
"To overcome both limitations described above, we introduce Bertram, an approach that combines a pretrained BERT language model BIBREF13 with Attentive Mimicking BIBREF19. To this end, let $d_h$ be the hidden dimension size and $l_\\text{max}$ be the number of layers for the BERT model being used. We denote with $e_{t}$ the (uncontextualized) embedding assigned to a token $t$ by BERT and, given a sequence of such uncontextualized embeddings $\\mathbf {e} = e_1, \\ldots , e_n$, we denote by $\\textbf {h}_j^l(\\textbf {e})$ the contextualized representation of the $j$-th token at layer $l$ when the model is given $\\mathbf {e}$ as input.",
|
| 55 |
+
"Given a word $w$ and a context $C = w_1, \\ldots , w_n$ in which it occurs, let $\\mathbf {t} = t_1, \\ldots , t_{m}$ with $m \\ge n$ be the sequence obtained from $C$ by (i) replacing $w$ with a [MASK] token and (ii) tokenizing the so-obtained sequence to match the BERT vocabulary; furthermore, let $i$ denote the index for which $t_i = \\texttt {[MASK]}$. Perhaps the most simple approach for obtaining a context embedding from $C$ using BERT is to define",
|
| 56 |
+
"where $\\mathbf {e} = e_{t_1}, \\ldots , e_{t_m}$. The so-obtained context embedding can then be combined with its form counterpart as described in Eq. DISPLAY_FORM8. While this achieves our first goal of using a more sophisticated context model that can potentially gain a deeper understanding of a word than just its broad topic, the so-obtained architecture still only combines form and context in a shallow fashion. We thus refer to it as the shallow variant of our model and investigate two alternative approaches (replace and add) that work as follows:",
|
| 57 |
+
"Replace: Before computing the context embedding, we replace the uncontextualized embedding of the [MASK] token with the word's surface-form embedding:",
|
| 58 |
+
"As during BERT pretraining, words chosen for prediction are replaced with [MASK] tokens only 80% of the time and kept unchanged 10% of the time, we hypothesize that even without further training, BERT is able to make use of form embeddings ingested this way.",
|
| 59 |
+
"Add: Before computing the context embedding, we prepad the input with the surface-form embedding of $w$, followed by a colon:",
|
| 60 |
+
"We also experimented with various other prefixes, but ended up choosing this particular strategy because we empirically found that after masking a token $t$, adding the sequence \u201c$t :$\u201d at the beginning helps BERT the most in recovering this very token at the masked position.",
|
| 61 |
+
"tnode/.style=rectangle, inner sep=0.1cm, minimum height=4ex, text centered,text height=1.5ex, text depth=0.25ex, opnode/.style=draw, rectangle, rounded corners, minimum height=4ex, minimum width=4ex, text centered, arrow/.style=draw,->,>=stealth",
|
| 62 |
+
"As for both variants, surface-form information is directly and deeply integrated into the computation of the context embedding, we do not require any further gating mechanism and may directly set $v_{(w,C)} = A \\cdot v^\\text{context}_{(w,C)}$.",
|
| 63 |
+
"However, we note that for the add variant, the contextualized representation of the [MASK] token is not the only natural candidate to be used for computing the final embedding: We might just as well look at the contextualized representation of the surface-form based embedding added at the very first position. Therefore, we also try a shallow combination of both embeddings. Note, however, that unlike FCM, we combine the contextualized representations \u2013 that is, the form part was already influenced by the context part and vice versa before combining them using a gate. For this combination, we define",
|
| 64 |
+
"with $A^{\\prime } \\in \\mathbb {R}^{d \\times d_h}$ being an additional learnable parameter. We then combine the two contextualized embeddings similar to Eq. DISPLAY_FORM8 as",
|
| 65 |
+
"where $\\alpha = g(h^\\text{form}_{(w,C)}, h^\\text{context}_{(w,C)})$. We refer to this final alternative as the add-gated approach. The model architecture for this variant can be seen in Figure FIGREF14 (left).",
|
| 66 |
+
"As in many cases, not just one, but a handful of contexts is known for a rare word, we follow the approach of BIBREF19 to deal with multiple contexts: We add an Attentive Mimicking head on top of our model, as can be seen in Figure FIGREF14 (right). That is, given a set of contexts $\\mathcal {C} = \\lbrace C_1, \\ldots , C_m\\rbrace $ and the corresponding embeddings $v_{(w,C_1)}, \\ldots , v_{(w,C_m)}$, we apply a self-attention mechanism to all embeddings, allowing the model to distinguish informative contexts from uninformative ones. The final embedding $v_{(w, \\mathcal {C})}$ is then a linear combination of the embeddings obtained from each context, where the weight of each embedding is determined based on the self-attention layer. For further details on this mechanism, we refer to BIBREF19."
|
| 67 |
+
],
|
| 68 |
+
[
|
| 69 |
+
"Like previous work, we use mimicking BIBREF8 as a training objective. That is, given a frequent word $w$ with known embedding $e_w$ and a set of corresponding contexts $\\mathcal {C}$, Bertram is trained to minimize $\\Vert e_w - v_{(w, \\mathcal {C})}\\Vert ^2$.",
|
| 70 |
+
"As training Bertram end-to-end requires much computation (processing a single training instance $(w,\\mathcal {C})$ is as costly as processing an entire batch of $|\\mathcal {C}|$ examples in the original BERT architecture), we resort to the following three-stage training process:",
|
| 71 |
+
"We train only the form part, i.e. our loss for a single example $(w, \\mathcal {C})$ is $\\Vert e_w - v^\\text{form}_{(w, \\mathcal {C})} \\Vert ^2$.",
|
| 72 |
+
"We train only the context part, minimizing $\\Vert e_w - A \\cdot v^\\text{context}_{(w, \\mathcal {C})} \\Vert ^2$ where the context embedding is obtained using the shallow variant of Bertram. Furthermore, we exclude all of BERT's parameters from our optimization.",
|
| 73 |
+
"We combine the pretrained form-only and context-only model and train all additional parameters.",
|
| 74 |
+
"Pretraining the form and context parts individually allows us to train the full model for much fewer steps with comparable results. Importantly, for the first two stages of our training procedure, we do not have to backpropagate through the entire BERT model to obtain all required gradients, drastically increasing the training speed."
|
| 75 |
+
],
|
| 76 |
+
[
|
| 77 |
+
"To measure the quality of rare word representations in a contextualized setting, we would ideally need text classification datasets with the following two properties:",
|
| 78 |
+
"A model that has no understanding of rare words at all should perform close to 0%.",
|
| 79 |
+
"A model that perfectly understands rare words should be able to classify every instance correctly.",
|
| 80 |
+
"Unfortunately, this requirement is not even remotely fulfilled by most commonly used datasets, simply because rare words occur in only a few entries and when they do, they are often of negligible importance.",
|
| 81 |
+
"To solve this problem, we devise a procedure to automatically transform existing text classification datasets such that rare words become important. For this procedure, we require a pretrained language model $M$ as a baseline, an arbitrary text classification dataset $\\mathcal {D}$ containing labelled instances $(\\mathbf {x}, y)$ and a substitution dictionary $S$, mapping each word $w$ to a set of rare synonyms $S(w)$. Given these ingredients, our procedure consists of three steps: (i) splitting the dataset into a train set and a set of test candidates, (ii) training the baseline model on the train set and (iii) modifying a subset of the test candidates to generate the final test set."
|
| 82 |
+
],
|
| 83 |
+
[
|
| 84 |
+
"We partition $\\mathcal {D}$ into a train set $\\mathcal {D}_\\text{train}$ and a set of test candidates, $\\mathcal {D}_\\text{cand}$, with the latter containing all instances $(\\mathbf {x},y) \\in \\mathcal {D}$ such that for at least one word $w$ in $\\mathbf {x}$, $S(w) \\ne \\emptyset $. Additionally, we require that the training set consists of at least one third of the entire data."
|
| 85 |
+
],
|
| 86 |
+
[
|
| 87 |
+
"We finetune $M$ on $\\mathcal {D}_\\text{train}$. Let $(\\mathbf {x}, y) \\in \\mathcal {D}_\\text{train}$ where $\\mathbf {x} = w_1, \\ldots , w_n$ is a sequence of words. We deviate from the standard finetuning procedure of BIBREF13 in three respects:",
|
| 88 |
+
"We randomly replace 5% of all words in $\\mathbf {x}$ with a [MASK] token. This allows the model to cope with missing or unknown words, a prerequisite for our final test set generation.",
|
| 89 |
+
"As an alternative to overwriting the language model's uncontextualized embeddings for rare words, we also want to allow models to simply add an alternative representation during test time, in which case we simply separate both representations by a slash. To accustom the language model to this duplication of words, we replace each word $w_i$ with \u201c$w_i$ / $w_i$\u201d with a probability of 10%. To make sure that the model does not simply learn to always focus on the first instance during training, we randomly mask each of the two repetitions with probability 25%.",
|
| 90 |
+
"We do not finetune the model's embedding layer. In preliminary experiments, we found this not to hurt performance."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"Let $p(y \\mid \\mathbf {x})$ be the probability that the finetuned model $M$ assigns to class $y$ given input $\\mathbf {x}$, and let",
|
| 94 |
+
"be the model's prediction for input $\\mathbf {x}$ where $\\mathcal {Y}$ denotes the set of all labels. For generating our test set, we only consider candidates that are classified correctly by the baseline model, i.e. candidates $(\\mathbf {x}, y) \\in \\mathcal {D}_\\text{cand}$ with $M(\\mathbf {x}) = y$. For each such entry, let $\\mathbf {x} = w_1, \\ldots , w_n$ and let $\\mathbf {x}_{w_i = t}$ be the sequence obtained from $\\mathbf {x}$ by replacing $w_i$ with $t$. We compute",
|
| 95 |
+
"i.e., we select the word $w_i$ whose masking pushes the model's prediction the furthest away from the correct label. If removing this word already changes the model's prediction \u2013 that is, $M(\\mathbf {x}_{w_i = \\texttt {[MASK]}}) \\ne y$ \u2013, we select a random rare synonym $\\hat{w}_i \\in S(w_i)$ and add $(\\mathbf {x}_{w_i = \\hat{w}_i}, y)$ to the test set. Otherwise, we repeat the above procedure; if the label still has not changed after masking up to 5 words, we discard the corresponding entry. All so-obtained test set entries $(\\mathbf {x}_{w_{i_1} = \\hat{w}_{i_1}, \\ldots , w_{i_k} = \\hat{w}_{i_k} }, y)$ have the following properties:",
|
| 96 |
+
"If each $w_{i_j}$ is replaced by a [MASK] token, the entry is classified incorrectly by $M$. In other words, understanding the words $w_{i_j}$ is essential for $M$ to determine the correct label.",
|
| 97 |
+
"If the model's internal representation of each $\\hat{w}_{i_j}$ is equal to its representation of $w_{i_j}$, the entry is classified correctly by $M$. That is, if the model is able to understand the rare words $\\hat{w}_{i_j}$ and to identify them as synonyms of ${w_{i_j}}$, it predicts the correct label for each instance.",
|
| 98 |
+
"It is important to notice that the so-obtained test set is very closely coupled to the baseline model $M$, because we selected the words to replace based on the model's predictions. Importantly, however, the model is never queried with any rare synonym during test set generation, so its representations of rare words are not taken into account for creating the test set. Thus, while the test set is not suitable for comparing $M$ with an entirely different model $M^{\\prime }$, it allows us to compare various strategies for representing rare words in the embedding space of $M$. A similar constraint can be found in the Definitional Nonce dataset BIBREF3, which is tied to a given embedding space based on Word2Vec BIBREF1."
|
| 99 |
+
],
|
| 100 |
+
[
|
| 101 |
+
"For our evaluation of Bertram, we largely follow the experimental setup of BIBREF0. Our implementation of Bertram is based on PyTorch BIBREF30 and the Transformers library of BIBREF31. Throughout all of our experiments, we use BERT$_\\text{base}$ as the underlying language model for Bertram. To obtain embeddings for frequent multi-token words during training, we use one-token approximation BIBREF0. Somewhat surprisingly, we found in preliminary experiments that excluding BERT's parameters from the finetuning procedure outlined in Section SECREF17 improves performance while speeding up training; we thus exclude them in the third step of our training procedure.",
|
| 102 |
+
"While BERT was trained on BooksCorpus BIBREF32 and a large Wikipedia dump, we follow previous work and train Bertram on only the much smaller Westbury Wikipedia Corpus (WWC) BIBREF33; this of course gives BERT a clear advantage over our proposed method. In order to at least partially compensate for this, in our downstream task experiments we gather the set of contexts $\\mathcal {C}$ for a given rare word from both the WWC and BooksCorpus during inference."
|
| 103 |
+
],
|
| 104 |
+
[
|
| 105 |
+
"We evalute Bertram on the WNLaMPro dataset of BIBREF0. This dataset consists of cloze-style phrases like",
|
| 106 |
+
"and the task is to correctly fill the slot (____) with one of several acceptable target words (e.g., \u201cfruit\u201d, \u201cbush\u201d and \u201cberry\u201d), which requires knowledge of the phrase's keyword (\u201clingonberry\u201d in the above example). As the goal of this dataset is to probe a language model's ability to understand rare words without any task-specific finetuning, BIBREF0 do not provide a training set. Furthermore, the dataset is partitioned into three subsets; this partition is based on the frequency of the keyword, with keywords occurring less than 10 times in the WWC forming the rare subset, those occurring between 10 and 100 times forming the medium subset, and all remaining words forming the frequent subset. As our focus is on improving representations for rare words, we evaluate our model only on the former two sets.",
|
| 107 |
+
"Results on WNLaMPro rare and medium are shown in Table TABREF34, where the mean reciprocal rank (MRR) is reported for BERT, Attentive Mimicking and Bertram. As can be seen, supplementing BERT with any of the proposed relearning methods results in noticeable improvements for the rare subset, with add clearly outperforming replace. Moreover, the add and add-gated variants of Bertram perform surprisingly well for more frequent words, improving the score for WNLaMPro-medium by 50% compared to BERT$_\\text{base}$ and 31% compared to Attentive Mimicking. This makes sense considering that compared to Attentive Mimicking, the key enhancement of Bertram lies in improving context representations and interconnection of form and context; naturally, the more contexts are given, the more this comes into play. Noticeably, despite being both based on and integrated into a BERT$_\\text{base}$ model, our architecture even outperforms a standalone BERT$_\\text{large}$ model by a large margin."
|
| 108 |
+
],
|
| 109 |
+
[
|
| 110 |
+
"To measure the effect of adding Bertram to BERT on downstream tasks, we apply the procedure described in Section SECREF4 to a commonly used textual entailment dataset as well as two text classification datasets: MNLI BIBREF21, AG's News BIBREF22 and DBPedia BIBREF23. For all three datasets, we use BERT$_\\text{base}$ as a baseline model and create the substitution dictionary $S$ using the synonym relation of WordNet BIBREF20 and the pattern library BIBREF34 to make sure that all synonyms have consistent parts of speech. As an additional source of word substitutions, we make use of the misspellings dataset of BIBREF25, which is based on query logs of a search engine. To prevent misspellings from dominating the resulting dataset, we only assign misspelling-based substitutes to randomly selected 10% of the words contained in each sentence. Motivated by the results on WNLaMPro-medium, we consider every word that occurs less than 100 times in the WWC and our BooksCorpus replica combined as being rare. Some examples of entries in the resulting datasets can be seen in Table TABREF35.",
|
| 111 |
+
"Just like for WNLaMPro, our default way of injecting Bertram embeddings into the baseline model is to replace the sequence of uncontextualized WordPiece tokens for a given rare word with its Bertram-based embedding. That is, given a sequence of uncontextualized token embeddings $\\mathbf {e} = e_1, \\ldots , e_n$ where $e_{i}, \\ldots , e_{i+j}$ with $1 \\le i \\le i+j \\le n$ is the sequence of WordPiece embeddings for a single rare word $w$, we replace $\\mathbf {e}$ with",
|
| 112 |
+
"By default, the set of contexts $\\mathcal {C}$ required for this replacement is obtained by collecting all sentences from the WWC and BooksCorpus in which $w$ occurs. As our model architecture allows us to easily include new contexts without requiring any additional training, we also try a variant where we add in-domain contexts by giving the model access to the texts found in the test set.",
|
| 113 |
+
"In addition to the procedure described above, we also try a variant where instead of replacing the original WordPiece embeddings for a given rare word, we merely add the Bertram-based embedding, separating both representations using a single slash:",
|
| 114 |
+
"As it performs best on the rare and medium subsets of WNLaMPro combined, we use only the add-gated variant of Bertram for all datasets. Results can be seen in Table TABREF37, where for each task, we report the accuracy on the entire dataset as well as scores obtained considering only instances where at least one word was replaced by a misspelling or a WordNet synonym, respectively. Consistent with results on WNLaMPro, combining BERT with Bertram outperforms both a standalone BERT model and one combined with Attentive Mimicking across all tasks. While keeping the original BERT embeddings in addition to Bertram's representation brings no benefit, adding in-domain data clearly helps for two out of three datasets. This makes sense as for rare words, every single additional context can be crucial for gaining a deeper understanding.",
|
| 115 |
+
"To further understand for which words using Bertram is helpful, in Figure FIGREF39 we look at the accuracy of BERT both with and without Bertram on all three tasks as a function of word frequency. That is, we compute the accuracy scores for both models when considering only entries $(\\mathbf {x}_{w_{i_1} = \\hat{w}_{i_1}, \\ldots , w_{i_k} = \\hat{w}_{i_k} }, y)$ where each substituted word $\\hat{w}_{i_j}$ occurs less than $c_\\text{max}$ times in WWC and BooksCorpus, for various values of $c_\\text{max}$. As one would expect, $c_\\text{max}$ is positively correlated with the accuracies of both models, showing that the rarer a word is, the harder it is to understand. Perhaps more interestingly, for all three datasets the gap between Bertram and BERT remains more or less constant regardless of $c_\\text{max}$. This indicates that using Bertram might also be useful for even more frequent words than the ones considered."
|
| 116 |
+
],
|
| 117 |
+
[
|
| 118 |
+
"We have introduced Bertram, a novel architecture for relearning high-quality representations of rare words. This is achieved by employing a powerful pretrained language model and deeply connecting surface-form and context information. By replacing important words with rare synonyms, we have created various downstream task datasets focusing on rare words; on all of these datasets, Bertram improves over a BERT model without special handling of rare words, demonstrating the usefulness of our proposed method.",
|
| 119 |
+
"As our analysis has shown that even for the most frequent words considered, using Bertram is still beneficial, future work might further investigate the limits of our proposed method. Furthermore, it would be interesting to explore more complex ways of incorporating surface-form information \u2013 e.g., by using a character-level CNN similar to the one of BIBREF27 \u2013 to balance out the potency of Bertram's form and context parts."
|
| 120 |
+
]
|
| 121 |
+
]
|
| 122 |
+
}
|
| 123 |
+
```
|
qasper-0160/instruction.md
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| 1 |
+
Name of Paper: Joint Entity Linking with Deep Reinforcement Learning
|
| 2 |
+
|
| 3 |
+
Question: How fast is the model compared to baselines?
|
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|
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| 1 |
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Name of Paper: Classification Betters Regression in Query-based Multi-document Summarisation Techniques for Question Answering: Macquarie University at BioASQ7b
|
| 2 |
+
|
| 3 |
+
Question: Did classification models perform better than previous regression one?
|
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|
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|
| 1 |
+
Name of Paper: Marrying Universal Dependencies and Universal Morphology
|
| 2 |
+
|
| 3 |
+
Question: Do they look for inconsistencies between different languages' annotations in UniMorph?
|
qasper-0170/instruction.md
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|
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| 1 |
+
Name of Paper: Marrying Universal Dependencies and Universal Morphology
|
| 2 |
+
|
| 3 |
+
Question: Do they look for inconsistencies between different UD treebanks?
|
qasper-0171/instruction.md
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|
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|
| 1 |
+
Name of Paper: Marrying Universal Dependencies and Universal Morphology
|
| 2 |
+
|
| 3 |
+
Question: Which languages do they validate on?
|
qasper-0176/instruction.md
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|
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|
| 1 |
+
Name of Paper: Revisiting Low-Resource Neural Machine Translation: A Case Study
|
| 2 |
+
|
| 3 |
+
Question: what amounts of size were used on german-english?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Low-Resource Translation Quality Compared Across Systems",
|
| 12 |
+
"Improving Low-Resource Neural Machine Translation",
|
| 13 |
+
"Mainstream Improvements",
|
| 14 |
+
"Language Representation",
|
| 15 |
+
"Hyperparameter Tuning",
|
| 16 |
+
"Lexical Model",
|
| 17 |
+
"Data and Preprocessing",
|
| 18 |
+
"PBSMT Baseline",
|
| 19 |
+
"NMT Systems",
|
| 20 |
+
"Results",
|
| 21 |
+
"Conclusions",
|
| 22 |
+
"Acknowledgments",
|
| 23 |
+
"Hyperparameters",
|
| 24 |
+
"Sample Translations"
|
| 25 |
+
],
|
| 26 |
+
"paragraphs": [
|
| 27 |
+
[
|
| 28 |
+
"While neural machine translation (NMT) has achieved impressive performance in high-resource data conditions, becoming dominant in the field BIBREF0 , BIBREF1 , BIBREF2 , recent research has argued that these models are highly data-inefficient, and underperform phrase-based statistical machine translation (PBSMT) or unsupervised methods in low-data conditions BIBREF3 , BIBREF4 . In this paper, we re-assess the validity of these results, arguing that they are the result of lack of system adaptation to low-resource settings. Our main contributions are as follows:"
|
| 29 |
+
],
|
| 30 |
+
[
|
| 31 |
+
"Figure FIGREF4 reproduces a plot by BIBREF3 which shows that their NMT system only outperforms their PBSMT system when more than 100 million words (approx. 5 million sentences) of parallel training data are available. Results shown by BIBREF4 are similar, showing that unsupervised NMT outperforms supervised systems if few parallel resources are available. In both papers, NMT systems are trained with hyperparameters that are typical for high-resource settings, and the authors did not tune hyperparameters, or change network architectures, to optimize NMT for low-resource conditions."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"The bulk of research on low-resource NMT has focused on exploiting monolingual data, or parallel data involving other language pairs. Methods to improve NMT with monolingual data range from the integration of a separately trained language model BIBREF5 to the training of parts of the NMT model with additional objectives, including a language modelling objective BIBREF5 , BIBREF6 , BIBREF7 , an autoencoding objective BIBREF8 , BIBREF9 , or a round-trip objective, where the model is trained to predict monolingual (target-side) training data that has been back-translated into the source language BIBREF6 , BIBREF10 , BIBREF11 . As an extreme case, models that rely exclusively on monolingual data have been shown to work BIBREF12 , BIBREF13 , BIBREF14 , BIBREF4 . Similarly, parallel data from other language pairs can be used to pre-train the network or jointly learn representations BIBREF15 , BIBREF16 , BIBREF17 , BIBREF18 , BIBREF19 , BIBREF20 , BIBREF21 .",
|
| 35 |
+
"While semi-supervised and unsupervised approaches have been shown to be very effective for some language pairs, their effectiveness depends on the availability of large amounts of suitable auxiliary data, and other conditions being met. For example, the effectiveness of unsupervised methods is impaired when languages are morphologically different, or when training domains do not match BIBREF22 ",
|
| 36 |
+
"More broadly, this line of research still accepts the premise that NMT models are data-inefficient and require large amounts of auxiliary data to train. In this work, we want to re-visit this point, and will focus on techniques to make more efficient use of small amounts of parallel training data. Low-resource NMT without auxiliary data has received less attention; work in this direction includes BIBREF23 , BIBREF24 ."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"We consider the hyperparameters used by BIBREF3 to be our baseline. This baseline does not make use of various advances in NMT architectures and training tricks. In contrast to the baseline, we use a BiDeep RNN architecture BIBREF25 , label smoothing BIBREF26 , dropout BIBREF27 , word dropout BIBREF28 , layer normalization BIBREF29 and tied embeddings BIBREF30 ."
|
| 40 |
+
],
|
| 41 |
+
[
|
| 42 |
+
"Subword representations such as BPE BIBREF31 have become a popular choice to achieve open-vocabulary translation. BPE has one hyperparameter, the number of merge operations, which determines the size of the final vocabulary. For high-resource settings, the effect of vocabulary size on translation quality is relatively small; BIBREF32 report mixed results when comparing vocabularies of 30k and 90k subwords.",
|
| 43 |
+
"In low-resource settings, large vocabularies result in low-frequency (sub)words being represented as atomic units at training time, and the ability to learn good high-dimensional representations of these is doubtful. BIBREF33 propose a minimum frequency threshold for subword units, and splitting any less frequent subword into smaller units or characters. We expect that such a threshold reduces the need to carefully tune the vocabulary size to the dataset, leading to more aggressive segmentation on smaller datasets."
|
| 44 |
+
],
|
| 45 |
+
[
|
| 46 |
+
"Due to long training times, hyperparameters are hard to optimize by grid search, and are often re-used across experiments. However, best practices differ between high-resource and low-resource settings. While the trend in high-resource settings is towards using larger and deeper models, BIBREF24 use smaller and fewer layers for smaller datasets. Previous work has argued for larger batch sizes in NMT BIBREF35 , BIBREF36 , but we find that using smaller batches is beneficial in low-resource settings. More aggressive dropout, including dropping whole words at random BIBREF37 , is also likely to be more important. We report results on a narrow hyperparameter search guided by previous work and our own intuition."
|
| 47 |
+
],
|
| 48 |
+
[
|
| 49 |
+
"Finally, we implement and test the lexical model by BIBREF24 , which has been shown to be beneficial in low-data conditions. The core idea is to train a simple feed-forward network, the lexical model, jointly with the original attentional NMT model. The input of the lexical model at time step INLINEFORM0 is the weighted average of source embeddings INLINEFORM1 (the attention weights INLINEFORM2 are shared with the main model). After a feedforward layer (with skip connection), the lexical model's output INLINEFORM3 is combined with the original model's hidden state INLINEFORM4 before softmax computation. INLINEFORM5 ",
|
| 50 |
+
" Our implementation adds dropout and layer normalization to the lexical model.",
|
| 51 |
+
"",
|
| 52 |
+
""
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"We use the TED data from the IWSLT 2014 German INLINEFORM0 English shared translation task BIBREF38 . We use the same data cleanup and train/dev split as BIBREF39 , resulting in 159000 parallel sentences of training data, and 7584 for development.",
|
| 56 |
+
"As a second language pair, we evaluate our systems on a Korean\u2013English dataset with around 90000 parallel sentences of training data, 1000 for development, and 2000 for testing.",
|
| 57 |
+
"For both PBSMT and NMT, we apply the same tokenization and truecasing using Moses scripts. For NMT, we also learn BPE subword segmentation with 30000 merge operations, shared between German and English, and independently for Korean INLINEFORM0 English.",
|
| 58 |
+
"To simulate different amounts of training resources, we randomly subsample the IWSLT training corpus 5 times, discarding half of the data at each step. Truecaser and BPE segmentation are learned on the full training corpus; as one of our experiments, we set the frequency threshold for subword units to 10 in each subcorpus (see SECREF7 ). Table TABREF14 shows statistics for each subcorpus, including the subword vocabulary.",
|
| 59 |
+
"Translation outputs are detruecased, detokenized, and compared against the reference with cased BLEU using sacreBLEU BIBREF40 , BIBREF41 . Like BIBREF39 , we report BLEU on the concatenated dev sets for IWSLT 2014 (tst2010, tst2011, tst2012, dev2010, dev2012)."
|
| 60 |
+
],
|
| 61 |
+
[
|
| 62 |
+
"We use Moses BIBREF42 to train a PBSMT system. We use MGIZA BIBREF43 to train word alignments, and lmplz BIBREF44 for a 5-gram LM. Feature weights are optimized on the dev set to maximize BLEU with batch MIRA BIBREF45 \u2013 we perform multiple runs where indicated. Unlike BIBREF3 , we do not use extra data for the LM. Both PBSMT and NMT can benefit from monolingual data, so the availability of monolingual data is no longer an exclusive advantage of PBSMT (see SECREF5 )."
|
| 63 |
+
],
|
| 64 |
+
[
|
| 65 |
+
"We train neural systems with Nematus BIBREF46 . Our baseline mostly follows the settings in BIBREF3 ; we use adam BIBREF47 and perform early stopping based on dev set BLEU. We express our batch size in number of tokens, and set it to 4000 in the baseline (comparable to a batch size of 80 sentences used in previous work).",
|
| 66 |
+
"We subsequently add the methods described in section SECREF3 , namely the bideep RNN, label smoothing, dropout, tied embeddings, layer normalization, changes to the BPE vocabulary size, batch size, model depth, regularization parameters and learning rate. Detailed hyperparameters are reported in Appendix SECREF7 ."
|
| 67 |
+
],
|
| 68 |
+
[
|
| 69 |
+
"Table TABREF18 shows the effect of adding different methods to the baseline NMT system, on the ultra-low data condition (100k words of training data) and the full IWSLT 14 training corpus (3.2M words). Our \"mainstream improvements\" add around 6\u20137 BLEU in both data conditions.",
|
| 70 |
+
"In the ultra-low data condition, reducing the BPE vocabulary size is very effective (+4.9 BLEU). Reducing the batch size to 1000 token results in a BLEU gain of 0.3, and the lexical model yields an additional +0.6 BLEU. However, aggressive (word) dropout (+3.4 BLEU) and tuning other hyperparameters (+0.7 BLEU) has a stronger effect than the lexical model, and adding the lexical model (9) on top of the optimized configuration (8) does not improve performance. Together, the adaptations to the ultra-low data setting yield 9.4 BLEU (7.2 INLINEFORM2 16.6). The model trained on full IWSLT data is less sensitive to our changes (31.9 INLINEFORM3 32.8 BLEU), and optimal hyperparameters differ depending on the data condition. Subsequently, we still apply the hyperparameters that were optimized to the ultra-low data condition (8) to other data conditions, and Korean INLINEFORM4 English, for simplicity.",
|
| 71 |
+
"For a comparison with PBSMT, and across different data settings, consider Figure FIGREF19 , which shows the result of PBSMT, our NMT baseline, and our optimized NMT system. Our NMT baseline still performs worse than the PBSMT system for 3.2M words of training data, which is consistent with the results by BIBREF3 . However, our optimized NMT system shows strong improvements, and outperforms the PBSMT system across all data settings. Some sample translations are shown in Appendix SECREF8 .",
|
| 72 |
+
"For comparison to previous work, we report lowercased and tokenized results on the full IWSLT 14 training set in Table TABREF20 . Our results far outperform the RNN-based results reported by BIBREF48 , and are on par with the best reported results on this dataset.",
|
| 73 |
+
"Table TABREF21 shows results for Korean INLINEFORM0 English, using the same configurations (1, 2 and 8) as for German\u2013English. Our results confirm that the techniques we apply are successful across datasets, and result in stronger systems than previously reported on this dataset, achieving 10.37 BLEU as compared to 5.97 BLEU reported by gu-EtAl:2018:EMNLP1."
|
| 74 |
+
],
|
| 75 |
+
[
|
| 76 |
+
"Our results demonstrate that NMT is in fact a suitable choice in low-data settings, and can outperform PBSMT with far less parallel training data than previously claimed. Recently, the main trend in low-resource MT research has been the better exploitation of monolingual and multilingual resources. Our results show that low-resource NMT is very sensitive to hyperparameters such as BPE vocabulary size, word dropout, and others, and by following a set of best practices, we can train competitive NMT systems without relying on auxiliary resources. This has practical relevance for languages where large amounts of monolingual data, or multilingual data involving related languages, are not available. Even though we focused on only using parallel data, our results are also relevant for work on using auxiliary data to improve low-resource MT. Supervised systems serve as an important baseline to judge the effectiveness of semisupervised or unsupervised approaches, and the quality of supervised systems trained on little data can directly impact semi-supervised workflows, for instance for the back-translation of monolingual data."
|
| 77 |
+
],
|
| 78 |
+
[
|
| 79 |
+
"Rico Sennrich has received funding from the Swiss National Science Foundation in the project CoNTra (grant number 105212_169888). Biao Zhang acknowledges the support of the Baidu Scholarship."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"Table TABREF23 lists hyperparameters used for the different experiments in the ablation study (Table 2). Hyperparameters were kept constant across different data settings, except for the validation interval and subword vocabulary size (see Table 1)."
|
| 83 |
+
],
|
| 84 |
+
[
|
| 85 |
+
"Table TABREF24 shows some sample translations that represent typical errors of our PBSMT and NMT systems, trained with ultra-low (100k words) and low (3.2M words) amounts of data. For unknown words such as blutbefleckten (`bloodstained') or Spaniern (`Spaniards', `Spanish'), PBSMT systems default to copying, while NMT systems produce translations on a subword-level, with varying success (blue-flect, bleed; spaniers, Spanians). NMT systems learn some syntactic disambiguation even with very little data, for example the translation of das and die as relative pronouns ('that', 'which', 'who'), while PBSMT produces less grammatical translation. On the flip side, the ultra low-resource NMT system ignores some unknown words in favour of a more-or-less fluent, but semantically inadequate translation: erobert ('conquered') is translated into doing, and richtig aufgezeichnet ('registered correctly', `recorded correctly') into really the first thing."
|
| 86 |
+
]
|
| 87 |
+
]
|
| 88 |
+
}
|
| 89 |
+
```
|
qasper-0177/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: Revisiting Low-Resource Neural Machine Translation: A Case Study
|
| 2 |
+
|
| 3 |
+
Question: what were their experimental results in the low-resource dataset?
|
qasper-0178/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: Revisiting Low-Resource Neural Machine Translation: A Case Study
|
| 2 |
+
|
| 3 |
+
Question: what are the methods they compare with in the korean-english dataset?
|
qasper-0179/instruction.md
ADDED
|
@@ -0,0 +1,89 @@
|
|
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|
|
|
|
|
|
|
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|
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|
|
|
|
|
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|
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|
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|
|
|
|
|
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|
|
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|
|
|
|
|
|
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|
|
|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: Revisiting Low-Resource Neural Machine Translation: A Case Study
|
| 2 |
+
|
| 3 |
+
Question: what pitfalls are mentioned in the paper?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Low-Resource Translation Quality Compared Across Systems",
|
| 12 |
+
"Improving Low-Resource Neural Machine Translation",
|
| 13 |
+
"Mainstream Improvements",
|
| 14 |
+
"Language Representation",
|
| 15 |
+
"Hyperparameter Tuning",
|
| 16 |
+
"Lexical Model",
|
| 17 |
+
"Data and Preprocessing",
|
| 18 |
+
"PBSMT Baseline",
|
| 19 |
+
"NMT Systems",
|
| 20 |
+
"Results",
|
| 21 |
+
"Conclusions",
|
| 22 |
+
"Acknowledgments",
|
| 23 |
+
"Hyperparameters",
|
| 24 |
+
"Sample Translations"
|
| 25 |
+
],
|
| 26 |
+
"paragraphs": [
|
| 27 |
+
[
|
| 28 |
+
"While neural machine translation (NMT) has achieved impressive performance in high-resource data conditions, becoming dominant in the field BIBREF0 , BIBREF1 , BIBREF2 , recent research has argued that these models are highly data-inefficient, and underperform phrase-based statistical machine translation (PBSMT) or unsupervised methods in low-data conditions BIBREF3 , BIBREF4 . In this paper, we re-assess the validity of these results, arguing that they are the result of lack of system adaptation to low-resource settings. Our main contributions are as follows:"
|
| 29 |
+
],
|
| 30 |
+
[
|
| 31 |
+
"Figure FIGREF4 reproduces a plot by BIBREF3 which shows that their NMT system only outperforms their PBSMT system when more than 100 million words (approx. 5 million sentences) of parallel training data are available. Results shown by BIBREF4 are similar, showing that unsupervised NMT outperforms supervised systems if few parallel resources are available. In both papers, NMT systems are trained with hyperparameters that are typical for high-resource settings, and the authors did not tune hyperparameters, or change network architectures, to optimize NMT for low-resource conditions."
|
| 32 |
+
],
|
| 33 |
+
[
|
| 34 |
+
"The bulk of research on low-resource NMT has focused on exploiting monolingual data, or parallel data involving other language pairs. Methods to improve NMT with monolingual data range from the integration of a separately trained language model BIBREF5 to the training of parts of the NMT model with additional objectives, including a language modelling objective BIBREF5 , BIBREF6 , BIBREF7 , an autoencoding objective BIBREF8 , BIBREF9 , or a round-trip objective, where the model is trained to predict monolingual (target-side) training data that has been back-translated into the source language BIBREF6 , BIBREF10 , BIBREF11 . As an extreme case, models that rely exclusively on monolingual data have been shown to work BIBREF12 , BIBREF13 , BIBREF14 , BIBREF4 . Similarly, parallel data from other language pairs can be used to pre-train the network or jointly learn representations BIBREF15 , BIBREF16 , BIBREF17 , BIBREF18 , BIBREF19 , BIBREF20 , BIBREF21 .",
|
| 35 |
+
"While semi-supervised and unsupervised approaches have been shown to be very effective for some language pairs, their effectiveness depends on the availability of large amounts of suitable auxiliary data, and other conditions being met. For example, the effectiveness of unsupervised methods is impaired when languages are morphologically different, or when training domains do not match BIBREF22 ",
|
| 36 |
+
"More broadly, this line of research still accepts the premise that NMT models are data-inefficient and require large amounts of auxiliary data to train. In this work, we want to re-visit this point, and will focus on techniques to make more efficient use of small amounts of parallel training data. Low-resource NMT without auxiliary data has received less attention; work in this direction includes BIBREF23 , BIBREF24 ."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"We consider the hyperparameters used by BIBREF3 to be our baseline. This baseline does not make use of various advances in NMT architectures and training tricks. In contrast to the baseline, we use a BiDeep RNN architecture BIBREF25 , label smoothing BIBREF26 , dropout BIBREF27 , word dropout BIBREF28 , layer normalization BIBREF29 and tied embeddings BIBREF30 ."
|
| 40 |
+
],
|
| 41 |
+
[
|
| 42 |
+
"Subword representations such as BPE BIBREF31 have become a popular choice to achieve open-vocabulary translation. BPE has one hyperparameter, the number of merge operations, which determines the size of the final vocabulary. For high-resource settings, the effect of vocabulary size on translation quality is relatively small; BIBREF32 report mixed results when comparing vocabularies of 30k and 90k subwords.",
|
| 43 |
+
"In low-resource settings, large vocabularies result in low-frequency (sub)words being represented as atomic units at training time, and the ability to learn good high-dimensional representations of these is doubtful. BIBREF33 propose a minimum frequency threshold for subword units, and splitting any less frequent subword into smaller units or characters. We expect that such a threshold reduces the need to carefully tune the vocabulary size to the dataset, leading to more aggressive segmentation on smaller datasets."
|
| 44 |
+
],
|
| 45 |
+
[
|
| 46 |
+
"Due to long training times, hyperparameters are hard to optimize by grid search, and are often re-used across experiments. However, best practices differ between high-resource and low-resource settings. While the trend in high-resource settings is towards using larger and deeper models, BIBREF24 use smaller and fewer layers for smaller datasets. Previous work has argued for larger batch sizes in NMT BIBREF35 , BIBREF36 , but we find that using smaller batches is beneficial in low-resource settings. More aggressive dropout, including dropping whole words at random BIBREF37 , is also likely to be more important. We report results on a narrow hyperparameter search guided by previous work and our own intuition."
|
| 47 |
+
],
|
| 48 |
+
[
|
| 49 |
+
"Finally, we implement and test the lexical model by BIBREF24 , which has been shown to be beneficial in low-data conditions. The core idea is to train a simple feed-forward network, the lexical model, jointly with the original attentional NMT model. The input of the lexical model at time step INLINEFORM0 is the weighted average of source embeddings INLINEFORM1 (the attention weights INLINEFORM2 are shared with the main model). After a feedforward layer (with skip connection), the lexical model's output INLINEFORM3 is combined with the original model's hidden state INLINEFORM4 before softmax computation. INLINEFORM5 ",
|
| 50 |
+
" Our implementation adds dropout and layer normalization to the lexical model.",
|
| 51 |
+
"",
|
| 52 |
+
""
|
| 53 |
+
],
|
| 54 |
+
[
|
| 55 |
+
"We use the TED data from the IWSLT 2014 German INLINEFORM0 English shared translation task BIBREF38 . We use the same data cleanup and train/dev split as BIBREF39 , resulting in 159000 parallel sentences of training data, and 7584 for development.",
|
| 56 |
+
"As a second language pair, we evaluate our systems on a Korean\u2013English dataset with around 90000 parallel sentences of training data, 1000 for development, and 2000 for testing.",
|
| 57 |
+
"For both PBSMT and NMT, we apply the same tokenization and truecasing using Moses scripts. For NMT, we also learn BPE subword segmentation with 30000 merge operations, shared between German and English, and independently for Korean INLINEFORM0 English.",
|
| 58 |
+
"To simulate different amounts of training resources, we randomly subsample the IWSLT training corpus 5 times, discarding half of the data at each step. Truecaser and BPE segmentation are learned on the full training corpus; as one of our experiments, we set the frequency threshold for subword units to 10 in each subcorpus (see SECREF7 ). Table TABREF14 shows statistics for each subcorpus, including the subword vocabulary.",
|
| 59 |
+
"Translation outputs are detruecased, detokenized, and compared against the reference with cased BLEU using sacreBLEU BIBREF40 , BIBREF41 . Like BIBREF39 , we report BLEU on the concatenated dev sets for IWSLT 2014 (tst2010, tst2011, tst2012, dev2010, dev2012)."
|
| 60 |
+
],
|
| 61 |
+
[
|
| 62 |
+
"We use Moses BIBREF42 to train a PBSMT system. We use MGIZA BIBREF43 to train word alignments, and lmplz BIBREF44 for a 5-gram LM. Feature weights are optimized on the dev set to maximize BLEU with batch MIRA BIBREF45 \u2013 we perform multiple runs where indicated. Unlike BIBREF3 , we do not use extra data for the LM. Both PBSMT and NMT can benefit from monolingual data, so the availability of monolingual data is no longer an exclusive advantage of PBSMT (see SECREF5 )."
|
| 63 |
+
],
|
| 64 |
+
[
|
| 65 |
+
"We train neural systems with Nematus BIBREF46 . Our baseline mostly follows the settings in BIBREF3 ; we use adam BIBREF47 and perform early stopping based on dev set BLEU. We express our batch size in number of tokens, and set it to 4000 in the baseline (comparable to a batch size of 80 sentences used in previous work).",
|
| 66 |
+
"We subsequently add the methods described in section SECREF3 , namely the bideep RNN, label smoothing, dropout, tied embeddings, layer normalization, changes to the BPE vocabulary size, batch size, model depth, regularization parameters and learning rate. Detailed hyperparameters are reported in Appendix SECREF7 ."
|
| 67 |
+
],
|
| 68 |
+
[
|
| 69 |
+
"Table TABREF18 shows the effect of adding different methods to the baseline NMT system, on the ultra-low data condition (100k words of training data) and the full IWSLT 14 training corpus (3.2M words). Our \"mainstream improvements\" add around 6\u20137 BLEU in both data conditions.",
|
| 70 |
+
"In the ultra-low data condition, reducing the BPE vocabulary size is very effective (+4.9 BLEU). Reducing the batch size to 1000 token results in a BLEU gain of 0.3, and the lexical model yields an additional +0.6 BLEU. However, aggressive (word) dropout (+3.4 BLEU) and tuning other hyperparameters (+0.7 BLEU) has a stronger effect than the lexical model, and adding the lexical model (9) on top of the optimized configuration (8) does not improve performance. Together, the adaptations to the ultra-low data setting yield 9.4 BLEU (7.2 INLINEFORM2 16.6). The model trained on full IWSLT data is less sensitive to our changes (31.9 INLINEFORM3 32.8 BLEU), and optimal hyperparameters differ depending on the data condition. Subsequently, we still apply the hyperparameters that were optimized to the ultra-low data condition (8) to other data conditions, and Korean INLINEFORM4 English, for simplicity.",
|
| 71 |
+
"For a comparison with PBSMT, and across different data settings, consider Figure FIGREF19 , which shows the result of PBSMT, our NMT baseline, and our optimized NMT system. Our NMT baseline still performs worse than the PBSMT system for 3.2M words of training data, which is consistent with the results by BIBREF3 . However, our optimized NMT system shows strong improvements, and outperforms the PBSMT system across all data settings. Some sample translations are shown in Appendix SECREF8 .",
|
| 72 |
+
"For comparison to previous work, we report lowercased and tokenized results on the full IWSLT 14 training set in Table TABREF20 . Our results far outperform the RNN-based results reported by BIBREF48 , and are on par with the best reported results on this dataset.",
|
| 73 |
+
"Table TABREF21 shows results for Korean INLINEFORM0 English, using the same configurations (1, 2 and 8) as for German\u2013English. Our results confirm that the techniques we apply are successful across datasets, and result in stronger systems than previously reported on this dataset, achieving 10.37 BLEU as compared to 5.97 BLEU reported by gu-EtAl:2018:EMNLP1."
|
| 74 |
+
],
|
| 75 |
+
[
|
| 76 |
+
"Our results demonstrate that NMT is in fact a suitable choice in low-data settings, and can outperform PBSMT with far less parallel training data than previously claimed. Recently, the main trend in low-resource MT research has been the better exploitation of monolingual and multilingual resources. Our results show that low-resource NMT is very sensitive to hyperparameters such as BPE vocabulary size, word dropout, and others, and by following a set of best practices, we can train competitive NMT systems without relying on auxiliary resources. This has practical relevance for languages where large amounts of monolingual data, or multilingual data involving related languages, are not available. Even though we focused on only using parallel data, our results are also relevant for work on using auxiliary data to improve low-resource MT. Supervised systems serve as an important baseline to judge the effectiveness of semisupervised or unsupervised approaches, and the quality of supervised systems trained on little data can directly impact semi-supervised workflows, for instance for the back-translation of monolingual data."
|
| 77 |
+
],
|
| 78 |
+
[
|
| 79 |
+
"Rico Sennrich has received funding from the Swiss National Science Foundation in the project CoNTra (grant number 105212_169888). Biao Zhang acknowledges the support of the Baidu Scholarship."
|
| 80 |
+
],
|
| 81 |
+
[
|
| 82 |
+
"Table TABREF23 lists hyperparameters used for the different experiments in the ablation study (Table 2). Hyperparameters were kept constant across different data settings, except for the validation interval and subword vocabulary size (see Table 1)."
|
| 83 |
+
],
|
| 84 |
+
[
|
| 85 |
+
"Table TABREF24 shows some sample translations that represent typical errors of our PBSMT and NMT systems, trained with ultra-low (100k words) and low (3.2M words) amounts of data. For unknown words such as blutbefleckten (`bloodstained') or Spaniern (`Spaniards', `Spanish'), PBSMT systems default to copying, while NMT systems produce translations on a subword-level, with varying success (blue-flect, bleed; spaniers, Spanians). NMT systems learn some syntactic disambiguation even with very little data, for example the translation of das and die as relative pronouns ('that', 'which', 'who'), while PBSMT produces less grammatical translation. On the flip side, the ultra low-resource NMT system ignores some unknown words in favour of a more-or-less fluent, but semantically inadequate translation: erobert ('conquered') is translated into doing, and richtig aufgezeichnet ('registered correctly', `recorded correctly') into really the first thing."
|
| 86 |
+
]
|
| 87 |
+
]
|
| 88 |
+
}
|
| 89 |
+
```
|
qasper-0182/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
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| 1 |
+
Name of Paper: Facilitating on-line opinion dynamics by mining expressions of causation. The case of climate change debates on The Guardian
|
| 2 |
+
|
| 3 |
+
Question: What is the technique used for text analysis and mining?
|
qasper-0183/instruction.md
ADDED
|
@@ -0,0 +1,120 @@
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|
| 1 |
+
Name of Paper: Facilitating on-line opinion dynamics by mining expressions of causation. The case of climate change debates on The Guardian
|
| 2 |
+
|
| 3 |
+
Question: What are the causal mapping methods employed?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction ::: Background",
|
| 11 |
+
"Introduction ::: Objective",
|
| 12 |
+
"Introduction ::: Data: the communicative setting of TheGuardian.com",
|
| 13 |
+
"Mining opinions and beliefs from texts",
|
| 14 |
+
"Mining opinions and beliefs from texts ::: Causal mapping methods and the climate change debate",
|
| 15 |
+
"Mining opinions and beliefs from texts ::: Automated causation tracking with the Penelope semantic frame extractor",
|
| 16 |
+
"Analyses and applications",
|
| 17 |
+
"Analyses and applications ::: Aggregation",
|
| 18 |
+
"Analyses and applications ::: Spatial renditions of TheGuardian.com's opinion landscape",
|
| 19 |
+
"Analyses and applications ::: Spatial renditions of TheGuardian.com's opinion landscape ::: A macro-level overview: causes addressed in the climate change debate",
|
| 20 |
+
"Analyses and applications ::: Spatial renditions of TheGuardian.com's opinion landscape ::: Micro-level investigations: opinions on nuclear power and global warming",
|
| 21 |
+
"From opinion observation to debate facilitation",
|
| 22 |
+
"From opinion observation to debate facilitation ::: Debate facilitation through models of alignment and polarization",
|
| 23 |
+
"Conclusion"
|
| 24 |
+
],
|
| 25 |
+
"paragraphs": [
|
| 26 |
+
[
|
| 27 |
+
"Over the past two decades, the rise of social media and the digitization of news and discussion platforms have radically transformed how individuals and groups create, process and share news and information. As Alan Rusbridger, former-editor-in-chief of the newspaper The Guardian has it, these technologically-driven shifts in the ways people communicate, organize themselves and express their beliefs and opinions, have",
|
| 28 |
+
"empower[ed] those that were never heard, creating a a new form of politics and turning traditional news corporations inside out. It is impossible to think of Donald Trump; of Brexit; of Bernie Sanders; of Podemos; of the growth of the far right in Europe; of the spasms of hope and violent despair in the Middle East and North Africa without thinking also of the total inversion of how news is created, shared and distributed. Much of it is liberating and and inspiring. Some of it is ugly and dark. And something - the centuries-old craft of journalism - is in danger of being lost BIBREF0.",
|
| 29 |
+
"Rusbridger's observation that the present media-ecology puts traditional notions of politics, journalism, trust and truth at stake is a widely shared one BIBREF1, BIBREF2, BIBREF3. As such, it has sparked interdisciplinary investigations, diagnoses and ideas for remedies across the economical, socio-political, and technological spectrum, challenging our existing assumptions and epistemologies BIBREF4, BIBREF5. Among these lines of inquiry, particular strands of research from the computational social sciences are addressing pressing questions of how emerging technologies and digital methods might be operationalized to regain a grip on the dynamics that govern the flow of on-line news and its associated multitudes of voices, opinions and conflicts. Could the information circulating on on-line (social) news platforms for instance be mined to better understand and analyze the problems facing our contemporary society? Might such data mining and analysis help us to monitor the growing number of social conflicts and crises due to cultural differences and diverging world-views? And finally, would such an approach potentially facilitate early detection of conflicts and even ways to resolve them before they turn violent?",
|
| 30 |
+
"Answering these questions requires further advances in the study of cultural conflict based on digital media data. This includes the development of fine-grained representations of cultural conflict based on theoretically-informed text analysis, the integration of game-theoretical approaches to models of polarization and alignment, as well as the construction of accessible tools and media-monitoring observatories: platforms that foster insight into the complexities of social behaviour and opinion dynamics through automated computational analyses of (social) media data. Through an interdisciplinary approach, the present article aims to make both a practical and theoretical contribution to these aspects of the study of opinion dynamics and conflict in new media environments."
|
| 31 |
+
],
|
| 32 |
+
[
|
| 33 |
+
"The objective of the present article is to critically examine possibilities and limitations of machine-guided exploration and potential facilitation of on-line opinion dynamics on the basis of an experimental data analytics pipeline or observatory for mining and analyzing climate change-related user comments from the news website of The Guardian (TheGuardian.com). Combining insights from the social and political sciences with computational methods for the linguistic analysis of texts, this observatory provides a series of spatial (network) representations of the opinion landscapes on climate change on the basis of causation frames expressed in news website comments. This allows for the exploration of opinion spaces at different levels of detail and aggregation.",
|
| 34 |
+
"Technical and theoretical questions related to the proposed method and infrastructure for the exploration and facilitation of debates will be discussed in three sections. The first section concerns notions of how to define what constitutes a belief or opinion and how these can be mined from texts. To this end, an approach based on the automated extraction of semantic frames expressing causation is proposed. The observatory thus builds on the theoretical premise that expressions of causation such as `global warming causes rises in sea levels' can be revelatory for a person or group's underlying belief systems. Through a further technical description of the observatory's data-analytical components, section two of the paper deals with matters of spatially modelling the output of the semantic frame extractor and how this might be achieved without sacrificing nuances of meaning. The final section of the paper, then, discusses how insights gained from technologically observing opinion dynamics can inform conceptual modelling efforts and approaches to on-line opinion facilitation. As such, the paper brings into view and critically evaluates the fundamental conceptual leap from machine-guided observation to debate facilitation and intervention.",
|
| 35 |
+
"Through the case examples from The Guardian's website and the theoretical discussions explored in these sections, the paper intends to make a twofold contribution to the fields of media studies, opinion dynamics and computational social science. Firstly, the paper introduces and chains together a number of data analytics components for social media monitoring (and facilitation) that were developed in the context of the <project name anonymized for review> infrastructure project. The <project name anonymized for review> infrastructure makes the components discussed in this paper available as open web services in order to foster reproducibility and further experimentation and development <infrastructure reference URL anonymized for review>. Secondly, and supplementing these technological and methodological gains, the paper addresses a number of theoretical, epistemological and ethical questions that are raised by experimental approaches to opinion exploration and facilitation. This notably includes methodological questions on the preservation of meaning through text and data mining, as well as the role of human interpretation, responsibility and incentivisation in observing and potentially facilitating opinion dynamics."
|
| 36 |
+
],
|
| 37 |
+
[
|
| 38 |
+
"In order to study on-line opinion dynamics and build the corresponding climate change opinion observatory discussed in this paper, a corpus of climate-change related news articles and news website comments was analyzed. Concretely, articles from the \u2018climate change\u2019 subsection from the news website of The Guardian dated from 2009 up to April 2019 were processed, along with up to 200 comments and associated metadata for articles where commenting was enabled at the time of publication. The choice for studying opinion dynamics using data from The Guardian is motivated by this news website's prominent position in the media landscape as well as its communicative setting, which is geared towards user engagement. Through this interaction with readers, the news platform embodies many of the recent shifts that characterize our present-day media ecology.",
|
| 39 |
+
"TheGuardian.com is generally acknowledged to be one of the UK's leading online newspapers, with 8,2 million unique visitors per month as of May 2013 BIBREF6. The website consists of a core news site, as well as a range of subsections that allow for further classification and navigation of articles. Articles related to climate change can for instance be accessed by navigating through the `News' section, over the subsection `environment', to the subsubsection `climate change' BIBREF7. All articles on the website can be read free of charge, as The Guardian relies on a business model that combines revenues from advertising, voluntary donations and paid subscriptions.",
|
| 40 |
+
"Apart from offering high-quality, independent journalism on a range of topics, a distinguishing characteristic of The Guardian is its penchant for reader involvement and engagement. Adopting to the changing media landscape and appropriating business models that fit the transition from print to on-line news media, the Guardian has transformed itself into a platform that enables forms of citizen journalism, blogging, and welcomes readers comments on news articles BIBREF0. In order for a reader to comment on articles, it is required that a user account is made, which provides a user with a unique user name and a user profile page with a stable URL. According to the website's help pages, providing users with an identity that is consistently recognized by the community fosters proper on-line community behaviour BIBREF8. Registered users can post comments on content that is open to commenting, and these comments are moderated by a dedicated moderation team according to The Guardian's community standards and participation guidelines BIBREF9. In support of digital methods and innovative approaches to journalism and data mining, The Guardian has launched an open API (application programming interface) through which developers can access different types of content BIBREF10. It should be noted that at the moment of writing this article, readers' comments are not accessible through this API. For the scientific and educational purposes of this paper, comments were thus consulted using a dedicated scraper.",
|
| 41 |
+
"Taking into account this community and technologically-driven orientation, the communicative setting of The Guardian from which opinions are to be mined and the underlying belief system revealed, is defined by articles, participating commenters and comment spheres (that is, the actual comments aggregated by user, individual article or collection of articles) (see Figure FIGREF4).",
|
| 42 |
+
"In this setting, articles (and previous comments on those articles) can be commented on by participating commenters, each of which bring to the debate his or her own opinions or belief system. What this belief system might consists of can be inferred on a number of levels, with varying degrees of precision. On the most general level, a generic description of the profile of the average reader of The Guardian can be informative. Such profiles have been compiled by market researchers with the purpose of informing advertisers about the demographic that might be reached through this news website (and other products carrying The Guardian's brand). As of the writing of this article, the audience The Guardian is presented to advertisers as a `progressive' audience:",
|
| 43 |
+
"Living in a world of unprecedented societal change, with the public narratives around politics, gender, body image, sexuality and diet all being challenged. The Guardian is committed to reflecting the progressive agenda, and reaching the crowd that uphold those values. It\u2019s helpful that we reach over half of progressives in the UK BIBREF11.",
|
| 44 |
+
"A second, equally high-level indicator of the beliefs that might be present on the platform, are the links through which articles on climate change can be accessed. An article on climate change might for instance be consulted through the environment section of the news website, but also through the business section. Assuming that business interests might potentially be at odds with environmental concerns, it could be hypothesized that the particular comment sphere for that article consists of at least two potentially clashing frames of mind or belief systems.",
|
| 45 |
+
"However, as will be expanded upon further in this article, truly capturing opinion dynamics requires a more systemic and fine-grained approach. The present article therefore proposes a method for harvesting opinions from the actual comment texts. The presupposition is thereby that comment spheres are marked by a diversity of potentially related opinions and beliefs. Opinions might for instance be connected through the reply structure that marks the comment section of an article, but this connection might also manifest itself on a semantic level (that is, the level of meaning or the actual contents of the comments). To capture this multidimensional, interconnected nature of the comment spheres, it is proposed to represent comment spheres as networks, where the nodes represent opinions and beliefs, and edges the relationships between these beliefs (see the spatial representation of beliefs infra). The use of precision language tools to extract such beliefs and their mutual relationships, as will be explored in the following sections, can open up new pathways of model validation and creation."
|
| 46 |
+
],
|
| 47 |
+
[
|
| 48 |
+
"In traditional experimental settings, survey techniques and associated statistical models provide researchers with established methods to gauge and analyze the opinions of a population. When studying opinion landscapes through on-line social media, however, harvesting beliefs from big textual data such as news website comments and developing or appropriating models for their analysis is a non-trivial task BIBREF12, BIBREF13, BIBREF14.",
|
| 49 |
+
"In the present context, two challenges related to data-gathering and text mining need to be addressed: (1) defining what constitutes an expression of an opinion or belief, and (2) associating this definition with a pattern that might be extracted from texts. Recent scholarship in the fields of natural language processing (NLP) and argumentation mining has yielded a range of instruments and methods for the (automatic) identification of argumentative claims in texts BIBREF15, BIBREF16. Adding to these instruments and methods, the present article proposes an approach in which belief systems or opinions on climate change are accessed through expressions of causation."
|
| 50 |
+
],
|
| 51 |
+
[
|
| 52 |
+
"The climate change debate is often characterized by expressions of causation, that is, expressions linking a certain cause with a certain effect. Cultural or societal clashes on climate change might for instance concern diverging assessments of whether global warming is man-made or not BIBREF17. Based on such examples, it can be stated that expressions of causation are closely associated with opinions or beliefs, and that as such, these expressions can be considered a valuable indicator for the range and diversity of the opinions and beliefs that constitute the climate change debate. The observatory under discussion therefore focuses on the extraction and analysis of linguistic patterns called causation frames. As will be further demonstrated in this section, the benefit of this causation-based approach is that it offers a systemic approach to opinion dynamics that comprises different layers of meaning, notably the cognitive or social meaningfulness of patterns on account of their being expressions of causation, as well as further lexical and semantic information that might be used for analysis and comparison.",
|
| 53 |
+
"The study of expressions of causation as a method for accessing and assessing belief systems and opinions has been formalized and streamlined since the 1970s. Pioneered by political scientist Robert Axelrod and others, this causal mapping method (also referred to as `cognitive mapping') was introduced as a means of reconstructing and evaluating administrative and political decision-making processes, based on the principle that",
|
| 54 |
+
"the notion of causation is vital to the process of evaluating alternatives. Regardless of philosophical difficulties involved in the meaning of causation, people do evaluate complex policy alternatives in terms of the consequences a particular choice would cause, and ultimately of what the sum of these effects would be. Indeed, such causal analysis is built into our language, and it would be very difficult for us to think completely in other terms, even if we tried BIBREF18.",
|
| 55 |
+
"Axelrod's causal mapping method comprises a set of conventions to graphically represent networks of causes and effects (the nodes in a network) as well as the qualitative aspects of this relation (the network\u2019s directed edges, notably assertions of whether the causal linkage is positive or negative). These causes and effects are to be extracted from relevant sources by means of a series of heuristics and an encoding scheme (it should be noted that for this task Axelrod had human readers in mind). The graphs resulting from these efforts provide a structural overview of the relations among causal assertions (and thus beliefs):",
|
| 56 |
+
"The basic elements of the proposed system are quite simple. The concepts a person uses are represented as points, and the causal links between these concepts are represented as arrows between these points. This gives a pictorial representation of the causal assertions of a person as a graph of points and arrows. This kind of representation of assertions as a graph will be called a cognitive map. The policy alternatives, all of the various causes and effects, the goals, and the ultimate utility of the decision maker can all be thought of as concept variables, and represented as points in the cognitive map. The real power of this approach appears when a cognitive map is pictured in graph form; it is then relatively easy to see how each of the concepts and causal relationships relate to each other, and to see the overall structure of the whole set of portrayed assertions BIBREF18.",
|
| 57 |
+
"In order to construct these cognitive maps based on textual information, Margaret Tucker Wrightson provides a set of reading and coding rules for extracting cause concepts, linkages (relations) and effect concepts from expressions in the English language. The assertion `Our present topic is the militarism of Germany, which is maintaining a state of tension in the Baltic Area' might for instance be encoded as follows: `the militarism of Germany' (cause concept), /+/ (a positive relationship), `maintaining a state of tension in the Baltic area' (effect concept) BIBREF19. Emphasizing the role of human interpretation, it is acknowledged that no strict set of rules can capture the entire spectrum of causal assertions:",
|
| 58 |
+
"The fact that the English language is as varied as those who use it makes the coder's task complex and difficult. No set of rules will completely solve the problems he or she might encounter. These rules, however, provide the coder with guidelines which, if conscientiously followed, will result in outcomes meeting social scientific standards of comparative validity and reliability BIBREF19.",
|
| 59 |
+
"To facilitate the task of encoders, the causal mapping method has gone through various iterations since its original inception, all the while preserving its original premises. Recent software packages have for instance been devised to support the data encoding and drawing process BIBREF20. As such, causal or cognitive mapping has become an established opinion and decision mining method within political science, business and management, and other domains. It has notably proven to be a valuable method for the study of recent societal and cultural conflicts. Thomas Homer-Dixon et al. for instance rely on cognitive-affective maps created from survey data to analyze interpretations of the housing crisis in Germany, Israeli attitudes toward the Western Wall, and moderate versus skeptical positions on climate change BIBREF21. Similarly, Duncan Shaw et al. venture to answer the question of `Why did Brexit happen?' by building causal maps of nine televised debates that were broadcast during the four weeks leading up to the Brexit referendum BIBREF22.",
|
| 60 |
+
"In order to appropriate the method of causal mapping to the study of on-line opinion dynamics, it needs to expanded from applications at the scale of human readers and relatively small corpora of archival documents and survey answers, to the realm of `big' textual data and larger quantities of information. This attuning of cognitive mapping methods to the large-scale processing of texts required for media monitoring necessarily involves a degree of automation, as will be explored in the next section."
|
| 61 |
+
],
|
| 62 |
+
[
|
| 63 |
+
"As outlined in the previous section, causal mapping is based on the extraction of so-called cause concepts, (causal) relations, and effect concepts from texts. The complexity of each of these these concepts can range from the relatively simple (as illustrated by the easily-identifiable cause and effect relation in the example of `German militarism' cited earlier), to more complex assertions such as `The development of international cooperation in all fields across the ideological frontiers will gradually remove the hostility and fear that poison international relations', which contains two effect concepts (viz. `the hostility that poisons international relations' and `the fear that poisons international relations'). As such, this statement would have to be encoded as a double relationship BIBREF19.",
|
| 64 |
+
"The coding guidelines in BIBREF19 further reflect that extracting cause and effect concepts from texts is an operation that works on both the syntactical and semantic levels of assertions. This can be illustrated by means of the guidelines for analyzing the aforementioned causal assertion on German militarism:",
|
| 65 |
+
"1. The first step is the realization of the relationship. Does a subject affect an object? 2. Having recognized that it does, the isolation of the cause and effects concepts is the second step. As the sentence structure indicates, \"the militarism of Germany\" is the causal concept, because it is the initiator of the action, while the direct object clause, \"a state of tension in the Baltic area,\" constitutes that which is somehow influenced, the effect concept BIBREF19.",
|
| 66 |
+
"In the field of computational linguistics, from which the present paper borrows part of its methods, this procedure for extracting information related to causal assertions from texts can be considered an instance of an operation called semantic frame extraction BIBREF23. A semantic frame captures a coherent part of the meaning of a sentence in a structured way. As documented in the FrameNet project BIBREF24, the Causation frame is defined as follows:",
|
| 67 |
+
"A Cause causes an Effect. Alternatively, an Actor, a participant of a (implicit) Cause, may stand in for the Cause. The entity Affected by the Causation may stand in for the overall Effect situation or event BIBREF25.",
|
| 68 |
+
"In a linguistic utterance such as a statement in a news website comment, the Causation frame can be evoked by a series of lexical units, such as `cause', `bring on', etc. In the example `If such a small earthquake CAUSES problems, just imagine a big one!', the Causation frame is triggered by the verb `causes', which therefore is called the frame evoking element. The Cause slot is filled by `a small earthquake', the Effect slot by `problems' BIBREF25.",
|
| 69 |
+
"In order to automatically mine cause and effects concepts from the corpus of comments on The Guardian, the present paper uses the Penelope semantic frame extractor: a tool that exploits the fact that semantic frames can be expressed as form-meaning mappings called constructions. Notably, frames were extracted from Guardian comments by focusing on the following lexical units (verbs, prepositions and conjunctions), listed in FrameNet as frame evoking elements of the Causation frame: Cause.v, Due to.prep, Because.c, Because of.prep, Give rise to.v, Lead to.v or Result in.v.",
|
| 70 |
+
"As illustrated by the following examples, the strings output by the semantic frame extractor adhere closely to the original utterance, preserving all of the the comments' causation frames real-world noisiness:",
|
| 71 |
+
"The output of the semantic frame extractor as such is used as the input for the ensuing pipeline components in the climate change opinion observatory. The aim of a further analysis of these frames is to find patterns in the beliefs and opinions they express. As will be discussed in the following section, which focuses on applications and cases, maintaining semantic nuances in this further analytic process foregrounds the role of models and aggregation levels."
|
| 72 |
+
],
|
| 73 |
+
[
|
| 74 |
+
"Based on the presupposition that relations between causation frames reveal beliefs, the output of the semantic frame extractor creates various opportunities for exploring opinion landscapes and empirically validating conceptual models for opinion dynamics.",
|
| 75 |
+
"In general, any alignment of conceptual models and real-world data is an exercise in compromising, as the idealized, abstract nature of models is likely to be at odds with the messiness of the actual data. Finding such a compromise might for instance involve a reduction of the simplicity or elegance of the model, or, on the other hand, an increased aggregation (and thus reduced granularity) of the data.",
|
| 76 |
+
"Addressing this challenge, the current section reflects on questions of data modelling, aggregation and meaning by exploring, through case examples, different spatial representations of opinion landscapes mined from the TheGuardian.com's comment sphere. These spatial renditions will be understood as network visualizations in which nodes represent argumentative statements (beliefs) and edges the degree of similarity between these statements. On the most general level, then, such a representation can consists of an overview of all the causes expressed in the corpus of climate change-related Guardian comments. This type of visualization provides a birds-eye view of the entire opinion landscape as mined from the comment texts. In turn, such a general overview might elicit more fine-grained, micro-level investigations, in which a particular cause is singled out and its more specific associated effects are mapped. These macro and micro level overviews come with their own proper potential for theory building and evaluation, as well as distinct requirements for the depth or detail of meaning that needs to be represented. To get the most general sense of an opinion landscape one might for instance be more tolerant of abstract renditions of beliefs (e.g. by reducing statements to their most frequently used terms), but for more fine-grained analysis one requires more context and nuance (e.g. adhering as closely as possible to the original comment)."
|
| 77 |
+
],
|
| 78 |
+
[
|
| 79 |
+
"As follows from the above, one of the most fundamental questions when building automated tools to observe opinion dynamics that potentially aim at advising means of debate facilitation concerns the level of meaning aggregation. A clear argumentative or causal association between, for instance, climate change and catastrophic events such as floods or hurricanes may become detectable by automatic causal frame tracking at the scale of large collections of articles where this association might appear statistically more often, but detection comes with great challenges when the aim is to classify certain sets of only a few statements in more free expression environments such as comment spheres.",
|
| 80 |
+
"In other words, the problem of meaning aggregation is closely related to issues of scale and aggregation over utterances. The more fine-grained the semantic resolution is, that is, the more specific the cause or effect is that one is interested in, the less probable it is to observe the same statement twice. Moreover, with every independent variable (such as time, different commenters or user groups, etc.), less data on which fine-grained opinion statements are to be detected is available. In the present case of parsed comments from TheGuardian.com, providing insights into the belief system of individual commenters, even if all their statements are aggregated over time, relies on a relatively small set of argumentative statements. This relative sparseness is in part due to the fact that the scope of the semantic frame extractor is confined to the frame evoking elements listed earlier, thus omitting more implicit assertions of causation (i.e. expressions of causation that can only be derived from context and from reading between the lines).",
|
| 81 |
+
"Similarly, as will be explored in the ensuing paragraphs, matters of scale and aggregation determine the types of further linguistic analyses that can be performed on the output of the frame extractor. Within the field of computational linguistics, various techniques have been developed to represent the meaning of words as vectors that capture the contexts in which these words are typically used. Such analyses might reveal patterns of statistical significance, but it is also likely that in creating novel, numerical representations of the original utterances, the semantic structure of argumentatively linked beliefs is lost.",
|
| 82 |
+
"In sum, developing opinion observatories and (potential) debate facilitators entails finding a trade-off, or, in fact, a middle way between macro- and micro-level analyses. On the one hand, one needs to leverage automated analysis methods at the scale of larger collections to maximum advantage. But one also needs to integrate opportunities to interactively zoom into specific aspects of interest and provide more fine-grained information at these levels down to the actual statements. This interplay between macro- and micro-level analyses is explored in the case studies below."
|
| 83 |
+
],
|
| 84 |
+
[
|
| 85 |
+
"The main purpose of the observatory under discussion is to provide insight into the belief structures that characterize the opinion landscape on climate change. For reasons outlined above, this raises questions of how to represent opinions and, correspondingly, determining which representation is most suited as the atomic unit of comparison between opinions. In general terms, the desired outcome of further processing of the output of the semantic frame extractor is a network representation in which similar cause or effect strings are displayed in close proximity to one another. A high-level description of the pipeline under discussion thus goes as follows. In a first step, it can be decided whether one wants to map cause statements or effect statements. Next, the selected statements are grouped per commenter (i.e. a list is made of all cause statements or effect statements per commenter). These statements are filtered in order to retain only nouns, adjectives and verbs (thereby also omitting frequently occurring verbs such as \u2018to be\u2019). The remaining words are then lemmatized, that is, reduced to their dictionary forms. This output is finally translated into a network representation, whereby nodes represent (aggregated) statements, and edges express the semantic relatedness between statements (based on a set overlap whereby the number of shared lemmata are counted).",
|
| 86 |
+
"As illustrated by two spatial renditions that were created using this approach and visualized using the network analysis tool Gephi BIBREF26, the labels assigned to these nodes (lemmata, full statements, or other) can be appropriated to the scope of the analysis."
|
| 87 |
+
],
|
| 88 |
+
[
|
| 89 |
+
"Suppose one wants to get a first idea about the scope and diversity of an opinion landscape, without any preconceived notions of this landscape's structure or composition. One way of doing this would be to map all of the causes that are mentioned in comments related to articles on climate change, that is, creating an overview of all the causes that have been retrieved by the frame extractor in a single representation. Such a representation would not immediately provide the granularity to state what the beliefs or opinions in the debates actually are, but rather, it might inspire a sense of what those opinions might be about, thus pointing towards potentially interesting phenomena that might warrant closer examination.",
|
| 90 |
+
"Figure FIGREF10, a high-level overview of the opinion landscape, reveals a number of areas to which opinions and beliefs might pertain. The top-left clusters in the diagram for instance reveal opinions about the role of people and countries, whereas on the right-hand side, we find a complementary cluster that might point to beliefs concerning the influence of high or increased CO2-emissions. In between, there is a cluster on power and energy sources, reflecting the energy debate's association to both issues of human responsibility and CO2 emissions. As such, the overview can already inspire, potentially at best, some very general hypotheses about the types of opinions that figure in the climate change debate."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"Based on the range of topics on which beliefs are expressed, a micro-level analysis can be conducted to reveal what those beliefs are and, for instance, whether they align or contradict each other. This can be achieved by singling out a cause of interest, and mapping out its associated effects.",
|
| 94 |
+
"As revealed by the global overview of the climate change opinion landscape, a portion of the debate concerns power and energy sources. One topic with a particularly interesting role in this debate is nuclear power. Figure FIGREF12 illustrates how a more detailed representation of opinions on this matter can be created by spatially representing all of the effects associated with causes containing the expression `nuclear power'. Again, similar beliefs (in terms of words used in the effects) are positioned closer to each other, thus facilitating the detection of clusters. Commenters on The Guardian for instance express concerns about the deaths or extinction that might be caused by this energy resource. They also voice opinions on its cleanliness, whether or not it might decrease pollution or be its own source of pollution, and how it reduces CO2-emissions in different countries.",
|
| 95 |
+
"Whereas the detailed opinion landscape on `nuclear power' is relatively limited in terms of the number of mined opinions, other topics might reveal more elaborate belief systems. This is for instance the case for the phenomenon of `global warming'. As shown in Figure FIGREF13, opinions on global warming are clustered around the idea of `increases', notably in terms of evaporation, drought, heat waves, intensity of cyclones and storms, etc. An adjacent cluster is related to `extremes', such as extreme summers and weather events, but also extreme colds."
|
| 96 |
+
],
|
| 97 |
+
[
|
| 98 |
+
"The observatory introduced in the preceding paragraphs provides preliminary insights into the range and scope of the beliefs that figure in climate change debates on TheGuardian.com. The observatory as such takes a distinctly descriptive stance, and aims to satisfy, at least in part, the information needs of researchers, activists, journalists and other stakeholders whose main concern is to document, investigate and understand on-line opinion dynamics. However, in the current information sphere, which is marked by polarization, misinformation and a close entanglement with real-world conflicts, taking a mere descriptive or neutral stance might not serve every stakeholder's needs. Indeed, given the often skewed relations between power and information, questions arise as to how media observations might in turn be translated into (political, social or economic) action. Knowledge about opinion dynamics might for instance inform interventions that remedy polarization or disarm conflict. In other words, the construction of (social) media observatories unavoidably lifts questions about the possibilities, limitations and, especially, implications of the machine-guided and human-incentivized facilitation of on-line discussions and debates.",
|
| 99 |
+
"Addressing these questions, the present paragraph introduces and explores the concept of a debate facilitator, that is, a device that extends the capabilities of the previously discussed observatory to also promote more interesting and constructive discussions. Concretely, we will conceptualize a device that reveals how the personal opinion landscapes of commenters relate to each other (in terms of overlap or lack thereof), and we will discuss what steps might potentially be taken on the basis of such representation to balance the debate. Geared towards possible interventions in the debate, such a device may thus go well beyond the observatory's objectives of making opinion processes and conflicts more transparent, which concomitantly raises a number of serious concerns that need to be acknowledged.",
|
| 100 |
+
"On rather fundamental ground, tools that steer debates in one way or another may easily become manipulative and dangerous instruments in the hands of certain interest groups. Various aspects of our daily lives are for instance already implicitly guided by recommender systems, the purpose and impact of which can be rather opaque. For this reason, research efforts across disciplines are directed at scrutinizing and rendering such systems more transparent BIBREF28. Such scrutiny is particularly pressing in the context of interventions on on-line communication platforms, which have already been argued to enforce affective communication styles that feed rather than resolve conflict. The objectives behind any facilitation device should therefore be made maximally transparent and potential biases should be fully acknowledged at every level, from data ingest to the dissemination of results BIBREF29. More concretely, the endeavour of constructing opinion observatories and facilitators foregrounds matters of `openness' of data and tools, security, ensuring data quality and representative sampling, accounting for evolving data legislation and policy, building communities and trust, and envisioning beneficial implications. By documenting the development process for a potential facilitation device, the present paper aims to contribute to these on-going investigations and debates. Furthermore, every effort has been made to protect the identities of the commenters involved. In the words of media and technology visionary Jaron Lanier, developers and computational social scientists entering this space should remain fundamentally aware of the fact that `digital information is really just people in disguise' BIBREF30.",
|
| 101 |
+
"With these reservations in mind, the proposed approach can be situated among ongoing efforts that lead from debate observation to facilitation. One such pathway, for instance, involves the construction of filters to detect hate speech, misinformation and other forms of expression that might render debates toxic BIBREF31, BIBREF32. Combined with community outreach, language-based filtering and detection tools have proven to raise awareness among social media users about the nature and potential implications of their on-line contributions BIBREF33. Similarly, advances can be expected from approaches that aim to extend the scope of analysis beyond descriptions of a present debate situation in order to model how a debate might evolve over time and how intentions of the participants could be included in such an analysis.",
|
| 102 |
+
"Progress in any of these areas hinges on a further integration of real-world data in the modelling process, as well as a further socio-technical and media-theoretical investigation of how activity on social media platforms and technologies correlate to real-world conflicts. The remainder of this section therefore ventures to explore how conceptual argument communication models for polarization and alignment BIBREF34 might be reconciled with real-world data, and how such models might inform debate facilitation efforts."
|
| 103 |
+
],
|
| 104 |
+
[
|
| 105 |
+
"As discussed in previous sections, news websites like TheGuardian.com establish a communicative settings in which agents (users, commenters) exchange arguments about different issues or topics. For those seeking to establish a healthy debate, it could thus be of interest to know how different users relate to each other in terms of their beliefs about a certain issue or topic (in this case climate change). Which beliefs are for instance shared by users and which ones are not? In other words, can we map patterns of alignment or polarization among users?",
|
| 106 |
+
"Figure FIGREF15 ventures to demonstrate how representations of opinion landscapes (generated using the methods outlined above) can be enriched with user information to answer such questions. Specifically, the graph represents the beliefs of two among the most active commenters in the corpus. The opinions of each user are marked using a colour coding scheme: red nodes represent the beliefs of the first user, blue nodes represent the beliefs of the second user. Nodes with a green colour represent beliefs that are shared by both users.",
|
| 107 |
+
"Taking into account again the factors of aggregation that were discussed in the previous section, Figure FIGREF15 supports some preliminary observations about the relationship between the two users in terms of their beliefs. Generally, given the fact that the graph concerns the two most active commenters on the website, it can be seen that the rendered opinion landscape is quite extensive. It is also clear that the belief systems of both users are not unrelated, as nodes of all colours can be found distributed throughout the graph. This is especially the case for the right-hand top cluster and right-hand bottom cluster of the graph, where green, red, and blue nodes are mixed. Since both users are discussing on articles on climate change, a degree of affinity between opinions or beliefs is to be expected.",
|
| 108 |
+
"Upon closer examination, a number of disparities between the belief systems of the two commenters can be detected. Considering the left-hand top cluster and center of the graph, it becomes clear that exclusively the red commenter is using a selection of terms related to the economical and socio-political realm (e.g. `people', `american', `nation', `government') and industry (e.g. `fuel', `industry', `car', etc.). The blue commenter, on the other hand, exclusively engages in using a range of terms that could be deemed more technical and scientific in nature (e.g. `feedback', `property', `output', `trend', `variability', etc.). From the graph, it also follows that the blue commenter does not enter into the red commenter's `social' segments of the graph as frequently as the red commenter enters the more scientifically-oriented clusters of the graph (although in the latter cases the red commenter does not use the specific technical terminology of the blue commenter). The cluster where both beliefs mingle the most (and where overlap can be observed), is the top right cluster. This overlap is constituted by very general terms (e.g. `climate', `change', and `science'). In sum, the graph reveals that the commenters' beliefs are positioned most closely to each other on the most general aspects of the debate, whereas there is less relatedness on the social and more technical aspects of the debate. In this regard, the depicted situation seemingly evokes currently on-going debates about the role or responsibilities of the people or individuals versus that of experts when it comes to climate change BIBREF35, BIBREF36, BIBREF37.",
|
| 109 |
+
"What forms of debate facilitation, then, could be based on these observations? And what kind of collective effects can be expected? As follows from the above, beliefs expressed by the two commenters shown here (which are selected based on their active participation rather than actual engagement or dialogue with one another) are to some extent complementary, as the blue commenter, who displays a scientifically-oriented system of beliefs, does not readily engage with the social topics discussed by the red commenter. As such, the overall opinion landscape of the climate change could potentially be enriched with novel perspectives if the blue commenter was invited to engage in a debate about such topics as industry and government. Similarly, one could explore the possibility of providing explanatory tools or additional references on occasions where the debate takes a more technical turn.",
|
| 110 |
+
"However, argument-based models of collective attitude formation BIBREF38, BIBREF34 also tell us to be cautious about such potential interventions. Following the theory underlying these models, different opinion groups prevailing during different periods of a debate will activate different argumentative associations. Facilitating exchange between users with complementary arguments supporting similar opinions may enforce biased argument pools BIBREF39 and lead to increasing polarization at the collective level. In the example considered here the two commenters agree on the general topic, but the analysis suggests that they might have different opinions about the adequate direction of specific climate change action. A more fine\u2013grained automatic detection of cognitive and evaluative associations between arguments and opinions is needed for a reliable use of models to predict what would come out of facilitating exchange between two specific users. In this regard, computational approaches to the linguistic analysis of texts such as semantic frame extraction offer productive opportunities for empirically modelling opinion dynamics. Extraction of causation frames allows one to disentangle cause-effect relations between semantic units, which provides a productive step towards mapping and measuring structures of cognitive associations. These opportunities are to be explored by future work."
|
| 111 |
+
],
|
| 112 |
+
[
|
| 113 |
+
"Ongoing transitions from a print-based media ecology to on-line news and discussion platforms have put traditional forms of news production and consumption at stake. Many challenges related to how information is currently produced and consumed come to a head in news website comment sections, which harbour the potential of providing new insights into how cultural conflicts emerge and evolve. On the basis of an observatory for analyzing climate change-related comments from TheGuardian.com, this article has critically examined possibilities and limitations of the machine-assisted exploration and possible facilitation of on-line opinion dynamics and debates.",
|
| 114 |
+
"Beyond technical and modelling pathways, this examination brings into view broader methodological and epistemological aspects of the use of digital methods to capture and study the flow of on-line information and opinions. Notably, the proposed approaches lift questions of computational analysis and interpretation that can be tied to an overarching tension between `distant' and `close reading' BIBREF40. In other words, monitoring on-line opinion dynamics means embracing the challenges and associated trade-offs that come with investigating large quantities of information through computational, text-analytical means, but doing this in such a way that nuance and meaning are not lost in the process.",
|
| 115 |
+
"Establishing productive cross-overs between the level of opinions mined at scale (for instance through the lens of causation frames) and the detailed, closer looks at specific conversations, interactions and contexts depends on a series of preliminaries. One of these is the continued availability of high-quality, accessible data. As the current on-line media ecology is recovering from recent privacy-related scandals (e.g. Cambridge Analytica), such data for obvious reasons is not always easy to come by. In the same legal and ethical vein, reproducibility and transparency of models is crucial to the further development of analytical tools and methods. As the experiments discussed in this paper have revealed, a key factor in this undertaking are human faculties of interpretation. Just like the encoding schemes introduced by Axelrod and others before the wide-spread use of computational methods, present-day pipelines and tools foreground the role of human agents as the primary source of meaning attribution.",
|
| 116 |
+
"<This project has received funding from the European Union\u2019s Horizon 2020 research and innovation programme under grant agreement No 732942 (Opinion Dynamics and Cultural Conflict in European Spaces \u2013 www.Odycceus.eu).>"
|
| 117 |
+
]
|
| 118 |
+
]
|
| 119 |
+
}
|
| 120 |
+
```
|
qasper-0184/instruction.md
ADDED
|
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|
| 1 |
+
Name of Paper: "Hinglish"Language -- Modeling a Messy Code-Mixed Language
|
| 2 |
+
|
| 3 |
+
Question: What is the previous work's model?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Introduction ::: Modeling challenges",
|
| 12 |
+
"Related Work ::: Transfer learning based approaches",
|
| 13 |
+
"Related Work ::: Hybrid models",
|
| 14 |
+
"Dataset and Features",
|
| 15 |
+
"Dataset and Features ::: Challenges",
|
| 16 |
+
"Model Architecture",
|
| 17 |
+
"Model Architecture ::: Loss function",
|
| 18 |
+
"Model Architecture ::: Models",
|
| 19 |
+
"Model Architecture ::: Hyper parameters",
|
| 20 |
+
"Results",
|
| 21 |
+
"Conclusion and Future work",
|
| 22 |
+
"References"
|
| 23 |
+
],
|
| 24 |
+
"paragraphs": [
|
| 25 |
+
[
|
| 26 |
+
"Hinglish is a linguistic blend of Hindi (very widely spoken language in India) and English (an associate language of urban areas) and is spoken by upwards of 350 million people in India. While the name is based on the Hindi language, it does not refer exclusively to Hindi, but is used in India, with English words blending with Punjabi, Gujarati, Marathi and Hindi. Sometimes, though rarely, Hinglish is used to refer to Hindi written in English script and mixing with English words or phrases. This makes analyzing the language very interesting. Its rampant usage in social media like Twitter, Facebook, Online blogs and reviews has also led to its usage in delivering hate and abuses in similar platforms. We aim to find such content in the social media focusing on the tweets. Hypothetically, if we can classify such tweets, we might be able to detect them and isolate them for further analysis before it reaches public. This will a great application of AI to the social cause and thus is motivating. An example of a simple, non offensive message written in Hinglish could be:",
|
| 27 |
+
"\"Why do you waste your time with <redacted content>. Aapna ghar sambhalta nahi(<redacted content>). Chale dusro ko basane..!!\"",
|
| 28 |
+
"The second part of the above sentence is written in Hindi while the first part is in English. Second part calls for an action to a person to bring order to his/her home before trying to settle others."
|
| 29 |
+
],
|
| 30 |
+
[
|
| 31 |
+
"From the modeling perspective there are couple of challenges introduced by the language and the labelled dataset. Generally, Hinglish follows largely fuzzy set of rules which evolves and is dependent upon the users preference. It doesn't have any formal definitions and thus the rules of usage are ambiguous. Thus, when used by different users the text produced may differ. Overall the challenges posed by this problem are:",
|
| 32 |
+
"Geographical variation: Depending upon the geography of origination, the content may be be highly influenced by the underlying region.",
|
| 33 |
+
"Language and phonetics variation: Based on a census in 2001, India has 122 major languages and 1599 other languages. The use of Hindi and English in a code switched setting is highly influenced by these language.",
|
| 34 |
+
"No grammar rules: Hinglish has no fixed set of grammar rules. The rules are inspired from both Hindi and English and when mixed with slur and slang produce large variation.",
|
| 35 |
+
"Spelling variation: There is no agreement on the spellings of the words which are mixed with English. For example to express love, a code mixed spelling, specially when used social platforms might be pyaar, pyar or pyr.",
|
| 36 |
+
"Dataset: Based on some earlier work, only available labelled dataset had 3189 rows of text messages of average length of 116 words and with a range of 1, 1295. Prior work addresses this concern by using Transfer Learning on an architecture learnt on about 14,500 messages with an accuracy of 83.90. We addressed this concern using data augmentation techniques applied on text data."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"Mathur et al. in their paper for detecting offensive tweets proposed a Ternary Trans-CNN model where they train a model architecture comprising of 3 layers of Convolution 1D having filter sizes of 15, 12 and 10 and kernel size of 3 followed by 2 dense fully connected layer of size 64 and 3. The first dense FC layer has ReLU activation while the last Dense layer had Softmax activation. They were able to train this network on a parallel English dataset provided by Davidson et al. The authors were able to achieve Accuracy of 83.9%, Precision of 80.2%, Recall of 69.8%.",
|
| 40 |
+
"The approach looked promising given that the dataset was merely 3189 sentences divided into three categories and thus we replicated the experiment but failed to replicate the results. The results were poor than what the original authors achieved. But, most of the model hyper-parameter choices where inspired from this work."
|
| 41 |
+
],
|
| 42 |
+
[
|
| 43 |
+
"In another localized setting of Vietnamese language, Nguyen et al. in 2017 proposed a Hybrid multi-channel CNN and LSTM model where they build feature maps for Vietnamese language using CNN to capture shorterm dependencies and LSTM to capture long term dependencies and concatenate both these feature sets to learn a unified set of features on the messages. These concatenated feature vectors are then sent to a few fully connected layers. They achieved an accuracy rate of 87.3% with this architecture."
|
| 44 |
+
],
|
| 45 |
+
[
|
| 46 |
+
"We used dataset, HEOT obtained from one of the past studies done by Mathur et al. where they annotated a set of cleaned tweets obtained from twitter for the conversations happening in Indian subcontinent. A labelled dataset for a corresponding english tweets were also obtained from a study conducted by Davidson et al. This dataset was important to employ Transfer Learning to our task since the number of labeled dataset was very small. Basic summary and examples of the data from the dataset are below:"
|
| 47 |
+
],
|
| 48 |
+
[
|
| 49 |
+
"The obtained data set had many challenges and thus a data preparation task was employed to clean the data and make it ready for the deep learning pipeline. The challenges and processes that were applied are stated below:",
|
| 50 |
+
"Messy text messages: The tweets had urls, punctuations, username mentions, hastags, emoticons, numbers and lots of special characters. These were all cleaned up in a preprocessing cycle to clean the data.",
|
| 51 |
+
"Stop words: Stop words corpus obtained from NLTK was used to eliminate most unproductive words which provide little information about individual tweets.",
|
| 52 |
+
"Transliteration: Followed by above two processes, we translated Hinglish tweets into English words using a two phase process",
|
| 53 |
+
"Transliteration: In phase I, we used translation API's provided by Google translation services and exposed via a SDK, to transliteration the Hinglish messages to English messages.",
|
| 54 |
+
"Translation: After transliteration, words that were specific to Hinglish were translated to English using an Hinglish-English dictionary. By doing this we converted the Hinglish message to and assortment of isolated words being presented in the message in a sequence that can also be represented using word to vector representation.",
|
| 55 |
+
"Data augmentation: Given the data set was very small with a high degree of imbalance in the labelled messages for three different classes, we employed a data augmentation technique to boost the learning of the deep network. Following techniques from the paper by Jason et al. was utilized in this setting that really helped during the training phase.Thsi techniques wasnt used in previous studies. The techniques were:",
|
| 56 |
+
"Synonym Replacement (SR):Randomly choose n words from the sentence that are not stop words. Replace each of these words with one of its synonyms chosen at random.",
|
| 57 |
+
"Random Insertion (RI):Find a random synonym of a random word in the sentence that is not a stop word. Insert that synonym into a random position in the sentence. Do this n times.",
|
| 58 |
+
"Random Swap (RS):Randomly choose two words in the sentence and swap their positions. Do this n times.",
|
| 59 |
+
"Random Deletion (RD):For each word in the sentence, randomly remove it with probability p.",
|
| 60 |
+
"Word Representation: We used word embedding representations by Glove for creating word embedding layers and to obtain the word sequence vector representations of the processed tweets. The pre-trained embedding dimension were one of the hyperparamaters for model. Further more, we introduced another bit flag hyperparameter that determined if to freeze these learnt embedding.",
|
| 61 |
+
"Train-test split: The labelled dataset that was available for this task was very limited in number of examples and thus as noted above few data augmentation techniques were applied to boost the learning of the network. Before applying augmentation, a train-test split of 78%-22% was done from the original, cleansed data set. Thus, 700 tweets/messages were held out for testing. All model evaluation were done in on the test set that got generated by this process. The results presented in this report are based on the performance of the model on the test set. The training set of 2489 messages were however sent to an offline pipeline for augmenting the data. The resulting training dataset was thus 7934 messages. the final distribution of messages for training and test was thus below:"
|
| 62 |
+
],
|
| 63 |
+
[
|
| 64 |
+
"We tested the performance of various model architectures by running our experiment over 100 times on a CPU based compute which later as migrated to GPU based compute to overcome the slow learning progress. Our universal metric for minimizing was the validation loss and we employed various operational techniques for optimizing on the learning process. These processes and its implementation details will be discussed later but they were learning rate decay, early stopping, model checkpointing and reducing learning rate on plateau."
|
| 65 |
+
],
|
| 66 |
+
[
|
| 67 |
+
"For the loss function we chose categorical cross entropy loss in finding the most optimal weights/parameters of the model. Formally this loss function for the model is defined as below:",
|
| 68 |
+
"The double sum is over the number of observations and the categories respectively. While the model probability is the probability that the observation i belongs to category c."
|
| 69 |
+
],
|
| 70 |
+
[
|
| 71 |
+
"Among the model architectures we experimented with and without data augmentation were:",
|
| 72 |
+
"Fully Connected dense networks: Model hyperparameters were inspired from the previous work done by Vo et al and Mathur et al. This was also used as a baseline model but we did not get appreciable performance on such architecture due to FC networks not being able to capture local and long term dependencies.",
|
| 73 |
+
"Convolution based architectures: Architecture and hyperparameter choices were chosen from the past study Deon on the subject. We were able to boost the performance as compared to only FC based network but we noticed better performance from architectures that are suitable to sequences such as text messages or any timeseries data.",
|
| 74 |
+
"Sequence models: We used SimpleRNN, LSTM, GRU, Bidirectional LSTM model architecture to capture long term dependencies of the messages in determining the class the message or the tweet belonged to.",
|
| 75 |
+
"Based on all the experiments we conducted below model had best performance related to metrics - Recall rate, F1 score and Overall accuracy."
|
| 76 |
+
],
|
| 77 |
+
[
|
| 78 |
+
"Choice of model parameters were in the above models were inspired from previous work done but then were tuned to the best performance of the Test dataset. Following parameters were considered for tuning.",
|
| 79 |
+
"Learning rate: Based on grid search the best performance was achieved when learning rate was set to 0.01. This value was arrived by a grid search on lr parameter.",
|
| 80 |
+
"Number of Bidirectional LSTM units: A set of 32, 64, 128 hidden activation units were considered for tuning the model. 128 was a choice made by Vo et al in modeling for Vietnamese language but with our experiments and with a small dataset to avoid overfitting to train dataset, a smaller unit sizes were considered.",
|
| 81 |
+
"Embedding dimension: 50, 100 and 200 dimension word representation from Glove word embedding were considered and the best results were obtained with 100d representation, consistent with choices made in the previous work.",
|
| 82 |
+
"Transfer learning on Embedding; Another bit flag for training the embedding on the train data or freezing the embedding from Glove was used. It was determined that set of pre-trained weights from Glove was best when it was fine tuned with Hinglish data. It provides evidence that a separate word or sentence level embedding when learnt for Hinglish text analysis will be very useful.",
|
| 83 |
+
"Number of dense FC layers.",
|
| 84 |
+
"Maximum length of the sequence to be considered: The max length of tweets/message in the dataset was 1265 while average was 116. We determined that choosing 200 resulted in the best performance."
|
| 85 |
+
],
|
| 86 |
+
[
|
| 87 |
+
"During our experimentation, it was evident that this is a hard problem especially detecting the hate speech, text in a code- mixed language. The best recall rate of 77 % for hate speech was obtained by a Bidirectional LSTM with 32 units with a recurrent drop out rate of 0.2. Precision wise GRU type of RNN sequence model faired better than other kinds for hate speech detection. On the other hand for detecting offensive and non offensive tweets, fairly satisfactory results were obtained. For offensive tweets, 92 % precision was and recall rate of 88% was obtained with GRU versus BiLSTM based models. Comparatively, Recall of 85 % and precision of 76 % was obtained by again GRU and BiLSTM based models as shown and marked in the results."
|
| 88 |
+
],
|
| 89 |
+
[
|
| 90 |
+
"The results of the experiments are encouraging on detective offensive vs non offensive tweets and messages written in Hinglish in social media. The utilization of data augmentation technique in this classification task was one of the vital contributions which led us to surpass results obtained by previous state of the art Hybrid CNN-LSTM based models. However, the results of the model for predicting hateful tweets on the contrary brings forth some shortcomings of the model. The biggest shortcoming on the model based on error analysis indicates less than generalized examples presented by the dataset. We also note that the embedding learnt from the Hinglish data set may be lacking and require extensive training to have competent word representations of Hinglish text. Given this learning's, we identify that creating word embeddings on much larger Hinglish corpora may have significant results. We also hypothesize that considering alternate methods than translation and transliteration may prove beneficial."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"[1] Mathur, Puneet and Sawhney, Ramit and Ayyar, Meghna and Shah, Rajiv, Did you offend me? classification of offensive tweets in hinglish language, Proceedings of the 2nd Workshop on Abusive Language Online (ALW2)",
|
| 94 |
+
"[2] Mathur, Puneet and Shah, Rajiv and Sawhney, Ramit and Mahata, Debanjan Detecting offensive tweets in hindi-english code-switched language Proceedings of the Sixth International Workshop on Natural Language Processing for Social Media",
|
| 95 |
+
"[3] Vo, Quan-Hoang and Nguyen, Huy-Tien and Le, Bac and Nguyen, Minh-Le Multi-channel LSTM-CNN model for Vietnamese sentiment analysis 2017 9th international conference on knowledge and systems engineering (KSE)",
|
| 96 |
+
"[4] Hochreiter, Sepp and Schmidhuber, J\u00fcrgen Long short-term memory Neural computation 1997",
|
| 97 |
+
"[5] Sinha, R Mahesh K and Thakur, Anil Multi-channel LSTM-CNN model for Vietnamese sentiment analysis 2017 9th international conference on knowledge and systems engineering (KSE)",
|
| 98 |
+
"[6] Pennington, Jeffrey and Socher, Richard and Manning, Christopher Glove: Global vectors for word representation Proceedings of the 2014 conference on empirical methods in natural language processing (EMNLP)",
|
| 99 |
+
"[7] Zhang, Lei and Wang, Shuai and Liu, Bing Deep learning for sentiment analysis: A survey Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery",
|
| 100 |
+
"[8] Caruana, Rich and Lawrence, Steve and Giles, C Lee Overfitting in neural nets: Backpropagation, conjugate gradient, and early stopping Advances in neural information processing systems",
|
| 101 |
+
"[9] Beale, Mark Hudson and Hagan, Martin T and Demuth, Howard B Neural network toolbox user\u2019s guide The MathWorks Incs",
|
| 102 |
+
"[10] Chollet, Fran\u00e7ois and others Keras: The python deep learning library Astrophysics Source Code Library",
|
| 103 |
+
"[11] Wei, Jason and Zou, Kai EDA: Easy Data Augmentation Techniques for Boosting Performance on Text Classification Tasks Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)"
|
| 104 |
+
]
|
| 105 |
+
]
|
| 106 |
+
}
|
| 107 |
+
```
|
qasper-0185/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
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|
|
| 1 |
+
Name of Paper: "Hinglish"Language -- Modeling a Messy Code-Mixed Language
|
| 2 |
+
|
| 3 |
+
Question: What dataset is used?
|
qasper-0193/instruction.md
ADDED
|
@@ -0,0 +1,112 @@
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|
| 1 |
+
Name of Paper: How Language-Neutral is Multilingual BERT?
|
| 2 |
+
|
| 3 |
+
Question: Are language-specific and language-neutral components disjunctive?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Related Work",
|
| 12 |
+
"Centering mBERT Representations",
|
| 13 |
+
"Probing Tasks",
|
| 14 |
+
"Probing Tasks ::: Language Identification.",
|
| 15 |
+
"Probing Tasks ::: Language Similarity.",
|
| 16 |
+
"Probing Tasks ::: Parallel Sentence Retrieval.",
|
| 17 |
+
"Probing Tasks ::: Word Alignment.",
|
| 18 |
+
"Probing Tasks ::: MT Quality Estimation.",
|
| 19 |
+
"Experimental Setup",
|
| 20 |
+
"Results ::: Language Identification.",
|
| 21 |
+
"Results ::: Language Similarity.",
|
| 22 |
+
"Results ::: Parallel Sentence Retrieval.",
|
| 23 |
+
"Results ::: Word Alignment.",
|
| 24 |
+
"Results ::: MT Quality Estimation.",
|
| 25 |
+
"Fine-tuning mBERT",
|
| 26 |
+
"Fine-tuning mBERT ::: UDify",
|
| 27 |
+
"Fine-tuning mBERT ::: lng-free",
|
| 28 |
+
"Conclusions"
|
| 29 |
+
],
|
| 30 |
+
"paragraphs": [
|
| 31 |
+
[
|
| 32 |
+
"Multilingual BERT (mBERT; BIBREF0) is gaining popularity as a contextual representation for various multilingual tasks, such as dependency parsing BIBREF1, BIBREF2, cross-lingual natural language inference (XNLI) or named-entity recognition (NER) BIBREF3, BIBREF4, BIBREF5.",
|
| 33 |
+
"BIBREF3 present an exploratory paper showing that mBERT can be used cross-lingually for zero-shot transfer in morphological and syntactic tasks, at least for typologically similar languages. They also study an interesting semantic task, sentence-retrieval, with promising initial results. Their work leaves many open questions in terms of how good the cross-lingual mBERT representation is for semantics, motivating our work.",
|
| 34 |
+
"In this paper, we directly assess the semantic cross-lingual properties of mBERT. To avoid methodological issues with zero-shot transfer (possible language overfitting, hyper-parameter tuning), we selected tasks that only involve a direct comparison of the representations: cross-lingual sentence retrieval, word alignment, and machine translation quality estimation (MT QE). Additionally, we explore how the language is represented in the embeddings by training language identification classifiers and assessing how the representation similarity corresponds to phylogenetic language families.",
|
| 35 |
+
"Our results show that the mBERT representations, even after language-agnostic fine-tuning, are not very language-neutral. However, the identity of the language can be approximated as a constant shift in the representation space. An even higher language-neutrality can still be achieved by a linear projection fitted on a small amount of parallel data.",
|
| 36 |
+
"Finally, we present attempts to strengthen the language-neutral component via fine-tuning: first, for multi-lingual syntactic and morphological analysis; second, towards language identity removal via a adversarial classifier."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"Since the publication of mBERT BIBREF0, many positive experimental results were published.",
|
| 40 |
+
"BIBREF2 reached impressive results in zero-shot dependency parsing. However, the representation used for the parser was a bilingual projection of the contextual embeddings based on word-alignment trained on parallel data.",
|
| 41 |
+
"BIBREF3 recently examined the cross-lingual properties of mBERT on zero-shot NER and part-of-speech (POS) tagging but the success of zero-shot transfer strongly depends on how typologically similar the languages are. Similarly, BIBREF4 trained good multilingual models for POS tagging, NER, and XNLI, but struggled to achieve good results in the zero-shot setup.",
|
| 42 |
+
"BIBREF3 assessed mBERT on cross-lingual sentence retrieval between three language pairs. They observed that if they subtract the average difference between the embeddings from the target language representation, the retrieval accuracy significantly increases. We systematically study this idea in the later sections.",
|
| 43 |
+
"Many experiments show BIBREF4, BIBREF5, BIBREF1 that downstream task models can extract relevant features from the multilingual representations. But these results do not directly show language-neutrality, i.e., to what extent are similar phenomena are represented similarly across languages. The models can obtain the task-specific information based on the knowledge of the language, which (as we show later) can be easily identified. Our choice of evaluation tasks eliminates this risk by directly comparing the representations. Limited success in zero-shot setups and the need for explicit bilingual projection in order to work well BIBREF3, BIBREF4, BIBREF6 also shows limited language neutrality of mBERT."
|
| 44 |
+
],
|
| 45 |
+
[
|
| 46 |
+
"Following BIBREF3, we hypothesize that a sentence representation in mBERT is composed of a language-specific component, which identifies the language of the sentence, and a language-neutral component, which captures the meaning of the sentence in a language-independent way. We assume that the language-specific component is similar across all sentences in the language.",
|
| 47 |
+
"We thus try to remove the language-specific information from the representations by centering the representations of sentences in each language so that their average lies at the origin of the vector space. We do this by estimating the language centroid as the mean of the mBERT representations for a set of sentences in that language and subtracting the language centroid from the contextual embeddings.",
|
| 48 |
+
"We then analyze the semantic properties of both the original and the centered representations using a range of probing tasks. For all tasks, we test all layers of the model. For tasks utilizing a single-vector sentence representation, we test both the vector corresponding to the [cls] token and mean-pooled states."
|
| 49 |
+
],
|
| 50 |
+
[
|
| 51 |
+
"We employ five probing tasks to evaluate the language neutrality of the representations."
|
| 52 |
+
],
|
| 53 |
+
[
|
| 54 |
+
"With a representation that captures all phenomena in a language-neutral way, it should be difficult to determine what language the sentence is written in. Unlike other tasks, language identification does require fitting a classifier. We train a linear classifier on top of a sentence representation to try to classify the language of the sentence."
|
| 55 |
+
],
|
| 56 |
+
[
|
| 57 |
+
"Experiments with POS tagging BIBREF3 suggest that similar languages tend to get similar representations on average. We quantify that observation by measuring how languages tend to cluster by the language families using V-measure over hierarchical clustering of the language centeroid BIBREF7."
|
| 58 |
+
],
|
| 59 |
+
[
|
| 60 |
+
"For each sentence in a multi-parallel corpus, we compute the cosine distance of its representation with representations of all sentences on the parallel side of the corpus and select the sentence with the smallest distance.",
|
| 61 |
+
"Besides the plain and centered [cls] and mean-pooled representations, we evaluate explicit projection into the \u201cEnglish space\u201d. For each language, we fit a linear regression projecting the representations into English representation space using a small set of parallel sentences."
|
| 62 |
+
],
|
| 63 |
+
[
|
| 64 |
+
"While sentence retrieval could be done with keyword spotting, computing bilingual alignment requires resolving detailed correspondence on the word level.",
|
| 65 |
+
"We find the word alignment as a minimum weighted edge cover of a bipartite graph. The graph connects the tokens of the sentences in the two languages and edges between them are weighted with the cosine distance of the token representation. Tokens that get split into multiple subwords are represented using the average of the embeddings of the subwords. Note that this algorithm is invariant to representation centering which would only change the edge weights by a constant offset.",
|
| 66 |
+
"We evaluate the alignment using the F$_1$ score over both sure and possible alignment links in a manually aligned gold standard."
|
| 67 |
+
],
|
| 68 |
+
[
|
| 69 |
+
"MT QE assesses the quality of an MT system output without having access to a reference translation.",
|
| 70 |
+
"The standard evaluation metric is the correlation with the Human-targeted Translation Error Rate which is the number of edit operations a human translator would need to do to correct the system output. This is a more challenging task than the two previous ones because it requires capturing more fine-grained differences in meaning.",
|
| 71 |
+
"We evaluate how cosine distance of the representation of the source sentence and of the MT output reflects the translation quality. In addition to plain and centered representations, we also test trained bilingual projection, and a fully supervised regression trained on training data."
|
| 72 |
+
],
|
| 73 |
+
[
|
| 74 |
+
"We use a pre-trained mBERT model that was made public with the BERT release. The model dimension is 768, hidden layer dimension 3072, self-attention uses 12 heads, the model has 12 layers. It uses a vocabulary of 120k wordpieces that is shared for all languages.",
|
| 75 |
+
"To train the language identification classifier, for each of the BERT languages we randomly selected 110k sentences of at least 20 characters from Wikipedia, and keep 5k for validation and 5k for testing for each language. The training data are also used for estimating the language centroids.",
|
| 76 |
+
"For parallel sentence retrieval, we use a multi-parallel corpus of test data from the WMT14 evaluation campaign BIBREF8 with 3,000 sentences in Czech, English, French, German, Hindi, and Russian. The linear projection experiment uses the WMT14 development data.",
|
| 77 |
+
"We use manually annotated word alignment datasets to evaluate word alignment between English on one side and Czech (2.5k sent.; BIBREF9), Swedish (192 sent.; BIBREF10), German (508 sent.), French (447 sent.; BIBREF11) and Romanian (248 sent.; BIBREF12) on the other side. We compare the results with FastAlign BIBREF13 that was provided with 1M additional parallel sentences from ParaCrawl BIBREF14 in addition to the test data.",
|
| 78 |
+
"For MT QE, we use English-German data provided for the WMT19 QE Shared Task BIBREF15 consisting training and test data with source senteces, their automatic translations, and manually corrections."
|
| 79 |
+
],
|
| 80 |
+
[
|
| 81 |
+
"Table TABREF7 shows that centering the sentence representations considerably decreases the accuracy of language identification, especially in the case of mean-pooled embeddings. This indicates that the proposed centering procedure does indeed remove the language-specific information to a great extent."
|
| 82 |
+
],
|
| 83 |
+
[
|
| 84 |
+
"Figure FIGREF9 is a tSNE plot BIBREF16 of the language centroids, showing that the similarity of the centroids tends to correspond to the similarity of the languages. Table TABREF10 confirms that the hierarchical clustering of the language centroids mostly corresponds to the language families."
|
| 85 |
+
],
|
| 86 |
+
[
|
| 87 |
+
"Results in Table TABREF12 reveal that the representation centering dramatically improves the retrieval accuracy, showing that it makes the representations more language-neutral. However, an explicitly learned projection of the representations leads to a much greater improvement, reaching a close-to-perfect accuracy, even though the projection was fitted on relatively small parallel data. The accuracy is higher for mean-pooled states than for the [cls] embedding and varies according to the layer of mBERT used (see Figure FIGREF13)."
|
| 88 |
+
],
|
| 89 |
+
[
|
| 90 |
+
"Table TABREF15 shows that word-alignment based on mBERT representations surpasses the outputs of the standard FastAlign tool even if it was provided large parallel corpus. This suggests that word-level semantics are well captured by mBERT contextual embeddings. For this task, learning an explicit projection had a negligible effect on the performance."
|
| 91 |
+
],
|
| 92 |
+
[
|
| 93 |
+
"Qualitative results of MT QE are tabulated in Table TABREF18. Unlike sentence retrieval, QE is more sensitive to subtle differences between sentences. Measuring the distance of the non-centered sentence vectors does not correlate with translation quality at all. Centering or explicit projection only leads to a mild correlation, much lower than a supervisedly trained regression;and even better performance is possible BIBREF15. The results show that the linear projection between the representations only captures a rough semantic correspondence, which does not seem to be sufficient for QE, where the most indicative feature appears to be sentence complexity."
|
| 94 |
+
],
|
| 95 |
+
[
|
| 96 |
+
"We also considered model fine-tuning towards stronger language neutrality. We evaluate two fine-tuned versions of mBERT: UDify, tuned for a multi-lingual dependency parser, and lng-free, tuned to jettison the language-specific information from the representations."
|
| 97 |
+
],
|
| 98 |
+
[
|
| 99 |
+
"The UDify model BIBREF1 uses mBERT to train a single model for dependency parsing and morphological analysis of 75 languages. During the parser training, mBERT is fine-tuned, which improves the parser accuracy. Results on zero-shot parsing suggest that the fine-tuning leads to more cross-lingual representations with respect to morphology and syntax.",
|
| 100 |
+
"However, our analyses show that fine-tuning mBERT for multilingual dependency parsing does not remove the language identity information from the representations and actually makes the representations less semantically cross-lingual."
|
| 101 |
+
],
|
| 102 |
+
[
|
| 103 |
+
"In this experiment, we try to make the representations more language-neutral by removing the language identity from the model using an adversarial approach. We continue training mBERT in a multi-task learning setup with the masked LM objective with the same sampling procedure BIBREF0 jointly with adversarial language ID classifiers BIBREF17. For each layer, we train one classifier for the [cls] token and one for the mean-pooled hidden states with the gradient reversal layer BIBREF18 between mBERT and the classifier.",
|
| 104 |
+
"The results reveal that the adversarial removal of language information succeeds in dramatically decreasing the accuracy of the language identification classifier; the effect is strongest in deeper layers for which the standard mBERT tend to perform better (see Figure FIGREF22). However, other tasksare not affected by the adversarial fine-tuning."
|
| 105 |
+
],
|
| 106 |
+
[
|
| 107 |
+
"Using a set of semantically oriented tasks that require explicit semantic cross-lingual representations, we showed that mBERT contextual embeddings do not represent similar semantic phenomena similarly and therefore they are not directly usable for zero-shot cross-lingual tasks.",
|
| 108 |
+
"Contextual embeddings of mBERT capture similarities between languages and cluster the languages by their families. Neither cross-lingual fine-tuning nor adversarial language identity removal breaks this property. A part of language information is encoded by the position in the embedding space, thus a certain degree of cross-linguality can be achieved by centering the representations for each language. Exploiting this property allows a good cross-lingual sentence retrieval performance and bilingual word alignment (which is invariant to the shift). A good cross-lingual representation can be achieved by fitting a supervised projection on a small parallel corpus."
|
| 109 |
+
]
|
| 110 |
+
]
|
| 111 |
+
}
|
| 112 |
+
```
|
qasper-0194/instruction.md
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
Name of Paper: How Language-Neutral is Multilingual BERT?
|
| 2 |
+
|
| 3 |
+
Question: How they show that mBERT representations can be split into a language-specific component and a language-neutral component?
|
qasper-0201/instruction.md
ADDED
|
@@ -0,0 +1,124 @@
|
|
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|
| 1 |
+
Name of Paper: Towards Faithfully Interpretable NLP Systems: How should we define and evaluate faithfulness?
|
| 2 |
+
|
| 3 |
+
Question: What faithfulness criteria does they propose?
|
| 4 |
+
|
| 5 |
+
## Full Paper Text (JSON)
|
| 6 |
+
|
| 7 |
+
```json
|
| 8 |
+
{
|
| 9 |
+
"section_name": [
|
| 10 |
+
"Introduction",
|
| 11 |
+
"Faithfulness vs. Plausibility",
|
| 12 |
+
"Inherently Interpretable?",
|
| 13 |
+
"Evaluation via Utility",
|
| 14 |
+
"Guidelines for Evaluating Faithfulness",
|
| 15 |
+
"Guidelines for Evaluating Faithfulness ::: Be explicit in what you evaluate.",
|
| 16 |
+
"Guidelines for Evaluating Faithfulness ::: Faithfulness evaluation should not involve human-judgement on the quality of interpretation.",
|
| 17 |
+
"Guidelines for Evaluating Faithfulness ::: Faithfulness evaluation should not involve human-provided gold labels.",
|
| 18 |
+
"Guidelines for Evaluating Faithfulness ::: Do not trust \u201cinherent interpretability\u201d claims.",
|
| 19 |
+
"Guidelines for Evaluating Faithfulness ::: Faithfulness evaluation of IUI systems should not rely on user performance.",
|
| 20 |
+
"Defining Faithfulness",
|
| 21 |
+
"Defining Faithfulness ::: Assumption 1 (The Model Assumption).",
|
| 22 |
+
"Defining Faithfulness ::: Assumption 2 (The Prediction Assumption).",
|
| 23 |
+
"Defining Faithfulness ::: Assumption 3 (The Linearity Assumption).",
|
| 24 |
+
"Is Faithful Interpretation Impossible?",
|
| 25 |
+
"Towards Better Faithfulness Criteria",
|
| 26 |
+
"Conclusion",
|
| 27 |
+
"Acknowledgements"
|
| 28 |
+
],
|
| 29 |
+
"paragraphs": [
|
| 30 |
+
[
|
| 31 |
+
"Fueled by recent advances in deep-learning and language processing, NLP systems are increasingly being used for prediction and decision-making in many fields BIBREF0, including sensitive ones such as health, commerce and law BIBREF1. Unfortunately, these highly flexible and highly effective neural models are also opaque. There is therefore a critical need for explaining learning-based models' decisions.",
|
| 32 |
+
"The emerging research topic of interpretability or explainability has grown rapidly in recent years. Unfortunately, not without growing pains.",
|
| 33 |
+
"One such pain is the challenge of defining\u2014and evaluating\u2014what constitutes a quality interpretation. Current approaches define interpretation in a rather ad-hoc manner, motivated by practical use-cases and applications. However, this view often fails to distinguish between distinct aspects of the interpretation's quality, such as readability, plausibility and faithfulness BIBREF2. We argue (\u00a7SECREF2, \u00a7SECREF5) such conflation is harmful, and that faithfulness should be defined and evaluated explicitly, and independently from plausibility.",
|
| 34 |
+
"Our main focus is the evaluation of the faithfulness of an explanation. Intuitively, a faithful interpretation is one that accurately represents the reasoning process behind the model's prediction. We find this to be a pressing issue in explainability: in cases where an explanation is required to be faithful, imperfect or misleading evaluation can have disastrous effects.",
|
| 35 |
+
"While literature in this area may implicitly or explicitly evaluate faithfulness for specific explanation techniques, there is no consistent and formal definition of faithfulness. We uncover three assumptions that underlie all these attempts. By making the assumptions explicit and organizing the literature around them, we \u201cconnect the dots\u201d between seemingly distinct evaluation methods, and also provide a basis for discussion regarding the desirable properties of faithfulness (\u00a7SECREF6).",
|
| 36 |
+
"Finally, we observe a trend by which faithfulness is treated as a binary property, followed by showing that an interpretation method is not faithful. We claim that this is unproductive (\u00a7SECREF7), as the assumptions are nearly impossible to satisfy fully, and it is all too easy to disprove the faithfulness of an interpretation method via a counter-example. What can be done? We argue for a more practical view of faithfulness, calling for a graded criteria that measures the extent and likelihood of an interpretation to be faithful, in practice (\u00a7SECREF8). While we started to work in this area, we pose the exact formalization of these criteria, and concrete evaluations methods for them, as a central challenge to the community for the coming future."
|
| 37 |
+
],
|
| 38 |
+
[
|
| 39 |
+
"There is considerable research effort in attempting to define and categorize the desiderata of a learned system's interpretation, most of which revolves around specific use-cases BIBREF17, BIBREF15.",
|
| 40 |
+
"Two particularly notable criteria, each useful for a different purposes, are plausibility and faithfulness. \u201cPlausibility\u201d refers to how convincing the interpretation is to humans, while \u201cfaithfulness\u201d refers to how accurately it reflects the true reasoning process of the model BIBREF2, BIBREF18.",
|
| 41 |
+
"Naturally, it is possible to satisfy one of these properties without the other. For example, consider the case of interpretation via post-hoc text generation\u2014where an additional \u201cgenerator\u201d component outputs a textual explanation of the model's decision, and the generator is learned with supervision of textual explanations BIBREF19, BIBREF20, BIBREF21. In this case, plausibility is the dominating property, while there is no faithfulness guarantee.",
|
| 42 |
+
"Despite the difference between the two criteria, many authors do not clearly make the distinction, and sometimes conflate the two. Moreoever, the majority of works do not explicitly name the criteria under consideration, even when they clearly belong to one camp or the other.",
|
| 43 |
+
"We argue that this conflation is dangerous. For example, consider the case of recidivism prediction, where a judge is exposed to a model's prediction and its interpretation, and the judge believes the interpretation to reflect the model's reasoning process. Since the interpretation's faithfulness carries legal consequences, a plausible but unfaithful interpretation may be the worst-case scenario. The lack of explicit claims by research may cause misinformation to potential users of the technology, who are not versed in its inner workings. Therefore, clear distinction between these terms is critical."
|
| 44 |
+
],
|
| 45 |
+
[
|
| 46 |
+
"A distinction is often made between two methods of achieving interpretability: (1) interpreting existing models via post-hoc techniques; and (2) designing inherently interpretable models. BIBREF29 argues in favor of inherently interpretable models, which by design claim to provide more faithful interpretations than post-hoc interpretation of black-box models.",
|
| 47 |
+
"We warn against taking this argumentation at face-value: a method being \u201cinherently interpretable\u201d is merely a claim that needs to be verified before it can be trusted. Indeed, while attention mechanisms have been considered as \u201cinherently interpretable\u201d BIBREF30, BIBREF31, recent work cast doubt regarding their faithfulness BIBREF32, BIBREF33, BIBREF18."
|
| 48 |
+
],
|
| 49 |
+
[
|
| 50 |
+
"While explanations have many different use-cases, such as model debugging, lawful guarantees or health-critical guarantees, one other possible use-case with particularly prominent evaluation literature is Intelligent User Interfaces (IUI), via Human-Computer Interaction (HCI), of automatic models assisting human decision-makers. In this case, the goal of the explanation is to increase the degree of trust between the user and the system, giving the user more nuance towards whether the system's decision is likely correct, or not. In the general case, the final evaluation metric is the performance of the user at their task BIBREF34. For example, BIBREF35 evaluate various explanations of a model in a setting of trivia question answering.",
|
| 51 |
+
"However, in the context of faithfulness, we must warn against HCI-inspired evaluation, as well: increased performance in this setting is not indicative of faithfulness; rather, it is indicative of correlation between the plausibility of the explanations and the model's performance.",
|
| 52 |
+
"To illustrate, consider the following fictional case of a non-faithful explanation system, in an HCI evaluation setting: the explanation given is a heat-map of the textual input, attributing scores to various tokens. Assume the system explanations behave in the following way: when the output is correct, the explanation consists of random content words; and when the output is incorrect, it consists of random punctuation marks. In other words, the explanation is more likely to appear plausible when the model is correct, while at the same time not reflecting the true decision process of the model. The user, convinced by the nicer-looking explanations, performs better using this system. However, the explanation consistently claimed random tokens to be highly relevant to the model's reasoning process. While the system is concretely useful, the claims given by the explanation do not reflect the model's decisions whatsoever (by design).",
|
| 53 |
+
"While the above scenario is extreme, this misunderstanding is not entirely unlikely, since any degree of correlation between plausibility and model performance will result in increased user performance, regardless of any notion of faithfulness."
|
| 54 |
+
],
|
| 55 |
+
[
|
| 56 |
+
"We propose the following guidelines for evaluating the faithfulness of explanations. These guidelines address common pitfalls and sub-optimal practices we observed in the literature."
|
| 57 |
+
],
|
| 58 |
+
[
|
| 59 |
+
"Conflating plausability and faithfulness is harmful. You should be explicit on which one of them you evaluate, and use suitable methodologies for each one. Of course, the same applies when designing interpretation techniques\u2014be clear about which properties are being prioritized."
|
| 60 |
+
],
|
| 61 |
+
[
|
| 62 |
+
"We note that: (1) humans cannot judge if an interpretation is faithful or not: if they understood the model, interpretation would be unnecessary; (2) for similar reasons, we cannot obtain supervision for this problem, either. Therefore, human judgement should not be involved in evaluation for faithfulness, as human judgement measures plausability."
|
| 63 |
+
],
|
| 64 |
+
[
|
| 65 |
+
"We should be able to interpret incorrect model predictions, just the same as correct ones. Evaluation methods that rely on gold labels are influenced by human priors on what should the model do, and again push the evaluation in the direction of plausability."
|
| 66 |
+
],
|
| 67 |
+
[
|
| 68 |
+
"Inherent interpretability is a claim until proven otherwise. Explanations provided by \u201cinherently interpretable\u201d models must be held to the same standards as post-hoc interpretation methods, and be evaluated for faithfulness using the same set of evaluation techniques."
|
| 69 |
+
],
|
| 70 |
+
[
|
| 71 |
+
"End-task user performance in HCI settings is merely indicative of correlation between plausibility and model performance, however small this correlation is. While important to evaluate the utility of the interpretations for some use-cases, it is unrelated to faithfulness."
|
| 72 |
+
],
|
| 73 |
+
[
|
| 74 |
+
"What does it mean for an interpretation method to be faithful? Intuitively, we would like the provided interpretation to reflect the true reasoning process of the model when making a decision. But what is a reasoning process of a model, and how can reasoning processes be compared to each other?",
|
| 75 |
+
"Lacking a standard definition, different works evaluate their methods by introducing tests to measure properties that they believe good interpretations should satisfy. Some of these tests measure aspects of faithfulness. These ad-hoc definitions are often unique to each paper and inconsistent with each other, making it hard to find commonalities.",
|
| 76 |
+
"We uncover three assumptions that underlie all these methods, enabling us to organize the literature along standardized axes, and relate seemingly distinct lines of work. Moreover, exposing the underlying assumptions enables an informed discussion regarding their validity and merit (we leave such a discussion for future work, by us or others).",
|
| 77 |
+
"These assumptions, to our knowledge, encapsulate the current working definitions of faithfulness used by the research community."
|
| 78 |
+
],
|
| 79 |
+
[
|
| 80 |
+
"Two models will make the same predictions if and only if they use the same reasoning process.",
|
| 81 |
+
"Corollary 1.1. An interpretation system is unfaithful if it results in different interpretations of models that make the same decisions.",
|
| 82 |
+
"As demonstrated by a recent example concerning NLP models, it can be used for proof by counter-example. Theoretically, if all possible models which can perfectly mimic the model's decisions also provide the same interpretations, then they could be deemed faithful. Conversely, showing that two models provide the same results but different interpretations, disprove the faithfulness of the method. BIBREF18 show how these counter-examples can be derived with adversarial training of models which can mimic the original model, yet provide different explanations.",
|
| 83 |
+
"Corollary 1.2. An interpretation is unfaithful if it results in different decisions than the model it interprets.",
|
| 84 |
+
"A more direct application of the Model Assumption is via the notion of fidelity BIBREF15, BIBREF8. For cases in which the explanation is itself a model capable of making decisions (e.g., decision trees or rule lists BIBREF36), fidelity is defined as the degree to which the explanation model can mimic the original model's decisions (as an accuracy score). For cases where the explanation is not a computable model, BIBREF37 propose a simple way of mapping explanations to decisions via crowd-sourcing, by asking humans to simulate the model's decision without any access to the model, and only access to the input and explanation (termed forward simulation). This idea is further explored and used in practice by BIBREF38."
|
| 85 |
+
],
|
| 86 |
+
[
|
| 87 |
+
"On similar inputs, the model makes similar decisions if and only if its reasoning is similar.",
|
| 88 |
+
"Corollary 2. An interpretation system is unfaithful if it provides different interpretations for similar inputs and outputs.",
|
| 89 |
+
"Since the interpretation serves as a proxy for the model's \u201creasoning\u201d, it should satisfy the same constraints. In other words, interpretations of similar decisions should be similar, and interpretations of dissimilar decisions should be dissimilar.",
|
| 90 |
+
"This assumption is more useful to disprove the faithfulness of an interpretation rather than prove it, since a disproof requires finding appropriate cases where the assumption doesn't hold, where a proof would require checking a (very large) satisfactory quantity of examples, or even the entire input space.",
|
| 91 |
+
"One recent discussion in the NLP community BIBREF33, BIBREF18 concerns the use of this underlying assumption for evaluating attention heat-maps as explanations. The former attempts to provide different explanations of similar decisions per instance. The latter critiques the former and is based more heavily on the model assumption, described above.",
|
| 92 |
+
"Additionally, BIBREF39 propose to introduce a constant shift to the input space, and evaluate whether the explanation changes significantly as the final decision stays the same. BIBREF16 formalize a generalization of this technique under the term interpretability robustness: interpretations should be invariant to small perturbations in the input (a direct consequence of the prediction assumption). BIBREF40 further expand on this notion as \u201cconsistency of the explanation with respect to the model\u201d. Unfortunately, robustness measures are difficult to apply in NLP settings due to the discrete input."
|
| 93 |
+
],
|
| 94 |
+
[
|
| 95 |
+
"Certain parts of the input are more important to the model reasoning than others. Moreover, the contributions of different parts of the input are independent from each other.",
|
| 96 |
+
"Corollary 3. Under certain circumstances, heat-map interpretations can be faithful.",
|
| 97 |
+
"This assumption is employed by methods that consider heat-maps (e.g., attention maps) over the input as explanations, particularly popular in NLP. Heat-maps are claims about which parts of the input are more relevant than others to the model's decision. As such, we can design \u201cstress tests\u201d to verify whether they uphold their claims.",
|
| 98 |
+
"One method proposed to do so is erasure, where the \u201cmost relevant\u201d parts of the input\u2014according to the explanation\u2014are erased from the input, in expectation that the model's decision will change BIBREF25, BIBREF42, BIBREF32. Otherwise, the \u201cleast relevant\u201d parts of the input may be erased, in expectation that the model's decision will not change BIBREF43. BIBREF44, BIBREF45 propose two measures of comprehensiveness and sufficiency as a formal generalization of erasure: as the degree by which the model is influenced by the removal of the high-ranking features, or by inclusion of solely the high-ranking features."
|
| 99 |
+
],
|
| 100 |
+
[
|
| 101 |
+
"The aforementioned assumptions are currently utilized to evaluate faithfulness in a binary manner, whether an interpretation is strictly faithful or not. Specifically, they are most often used to show that a method is not faithful, by constructing cases in which the assumptions do not hold for the suggested method. In other words, there is a clear trend of proof via counter-example, for various interpretation methods, that they are not globally faithful.",
|
| 102 |
+
"We claim that this is unproductive, as we expect these various methods to consistently result in negative (not faithful) results, continuing the current trend. This follows because an interpretation functions as an approximation of the model or decision's true reasoning process, so it by definition loses information. By the pigeonhole principle, there will be inputs with deviation between interpretation and reasoning.",
|
| 103 |
+
"This is observed in practice, in numerous work that show adversarial behavior, or pathological behaviours, that arise from the deeply non-linear and high-dimensional decision boundaries of current models. Furthermore, because we lack supervision regarding which models or decisions are indeed mappable to human-readable concepts, we cannot ignore the approximation errors.",
|
| 104 |
+
"This poses a high bar for explanation methods to fulfill, a bar which we estimate will not be overcome soon, if at all. What should we do, then, if we desire a system that provides faithful explanations?"
|
| 105 |
+
],
|
| 106 |
+
[
|
| 107 |
+
"We argue that a way out of this standstill is in a more practical and nuanced methodology for defining and evaluating faithfulness. We propose the following challenge to the community: We must develop formal definition and evaluation for faithfulness that allows us the freedom to say when a method is sufficiently faithful to be useful in practice.",
|
| 108 |
+
"We note two possible approaches to this end:",
|
| 109 |
+
"Across models and tasks: The degree (as grayscale) of faithfulness at the level of specific models and tasks. Perhaps some models or tasks allow sufficiently faithful interpretation, even if the same is not true for others.",
|
| 110 |
+
"For example, the method may not be faithful for some question-answering task, but faithful for movie review sentiment, perhaps based on various syntactic and semantic attributes of those tasks.",
|
| 111 |
+
"Across input space: The degree of faithfulness at the level of subspaces of the input space, such as neighborhoods of similar inputs, or singular inputs themselves. If we are able to say with some degree of confidence whether a specific decision's explanation is faithful to the model, even if the interpretation method is not considered universally faithful, it can be used with respect to those specific areas or instances only."
|
| 112 |
+
],
|
| 113 |
+
[
|
| 114 |
+
"The opinion proposed in this paper is two-fold:",
|
| 115 |
+
"First, interpretability evaluation often conflates evaluating faithfulness and plausibility together. We should tease apart the two definitions and focus solely on evaluating faithfulness without any supervision or influence of the convincing power of the interpretation.",
|
| 116 |
+
"Second, faithfulness is often evaluated in a binary \u201cfaithful or not faithful\u201d manner, and we believe strictly faithful interpretation is a \u201cunicorn\u201d which will likely never be found. We should instead evaluate faithfulness on a more nuanced \u201cgrayscale\u201d that allows interpretations to be useful even if they are not globally and definitively faithful."
|
| 117 |
+
],
|
| 118 |
+
[
|
| 119 |
+
"We thank Yanai Elazar for welcome input on the presentation and organization of the paper. We also thank the reviewers for additional feedback and pointing to relevant literature in HCI and IUI.",
|
| 120 |
+
"This project has received funding from the Europoean Research Council (ERC) under the Europoean Union's Horizon 2020 research and innovation programme, grant agreement No. 802774 (iEXTRACT)."
|
| 121 |
+
]
|
| 122 |
+
]
|
| 123 |
+
}
|
| 124 |
+
```
|