| | --- |
| | license: apache-2.0 |
| | language: |
| | - zh |
| | --- |
| | # Text Summarization |
| | This is a assignment of Applied Deep Learning which is a course of National Taiwan University(NTU). |
| | ### Task Description：Chinese News Summarization (Title Generation) |
| | input(news content)： |
| | ``` |
| | Anker在此次CES 2021中，宣布以旗下Soundcore品牌推出新款真無線藍牙耳機Liberty Air 2 Pro，同時也確定引進台灣市場。\nLiberty Air 2 Pro本身採入耳式耳塞設計，並且透過耳機外側觸控手勢進行操作，同時使用者也能配合App設定手勢對應功能。通話部分則可透過6組麥克風加強收音，以及降噪效果，使得藉由耳機通話也不會被環境噪音干擾。\n，\n至於耳機內部則採用11mm發聲單體，在主動式降噪功能對應交通、室內、室外三種模式，甚至可透過「完全通透」模式，讓使用者聆聽音樂之餘，仍可聽見環境周圍聲音，而「人聲增強通透模式」則可針對附近人聲部分提高音量，並且降低背景噪音，讓使用者在配戴耳機情況下仍可聽見他人說話，或是附近廣播內容。\n跟之前的真無線藍牙耳機一樣，Liberty Air 2 Pro也能透過專屬App的HearID 2.0工具分析耳朵聆聽偏好，讓耳機能配合個人需求發揮更貼切的聲音表現，或是由使用者自行調整音場效果。\n至於電力表現部分，Liberty Air 2 Pro在開啟主動式降噪時的電池續航表現為6小時，關閉主動式降噪功能則可達7小時左右，搭配充電盒使用的話，則最長使用時間可達21小時與26小時，充電盒本身也支援Qi無線充電。\n目前Liberty Air 2 Pro總計提供粉色、黑色、白色與藍色四款設計，目前已經開放Soundcore官網等通路銷售，至於台灣市場則預計透過智選家、三創友均選物ANKER旗艦店、台中My Ear 耳機專門店、法雅客、良興、三井3C等通路預購，建議售價為新台幣4280元。\n《原文刊登於合作媒體mashdigi，聯合新聞網獲授權轉載。》 |
| | ``` |
| | output(news title)： |
| | ``` |
| | Anker新款真無線藍牙耳機Liberty Air 2 Pro 引進台灣市場 |
| | ``` |
| | ### Objective |
| | - Fine-tune a pre-trained model：[google/mt5-small](https://huggingface.co/google/mt5-small) to pass the baseline. |
| | - Compare the difference between beam search, top k sampling, top p sampling, temperature. |
| | ``` |
| | Baseline(f1-score)：rouge-1: 22.0, rouge-2: 8.5, rouge-L: 20.5 |
| | ``` |
| | ### Experiments |
| | - Greedy |
| | After the model generate the probility of every token as result, Greedy is the simplest way to choose the next word with most probable word(argmax). |
| | However, there is a problem that it's easy to choose the duplicate word with Greedy strategy. |
| | ``` |
| | Greedy Result(f1-score)：rouge-1: 1.5, rouge-2: 0.9, rouge-L: 1.4 |
| | ``` |
| | - Beam Search |
| | Beam Search strategy is keeping track of the k most probable sentences and finding the best one as a result. |
| | Therefore, if beam size is setting as 1, it becomes Greedy. We can say that beam search kind of solves the problem of Greedy. |
| | However, if beam size is too large, the result will turn into too generic and less relevant though the result is safe and "correct". |
| | For example |
| | ``` |
| | input： |
| | I love to listen Taylor Swift's songs so I decide to participate the concert of Taylor. |
| | output： |
| | What do you like to listen？ |
| | ``` |
| | ``` |
| | beam size = 5 |
| | Beam Search Result(f1-score)：rouge-1: 7.4, rouge-2: 1.9, rouge-L: 6.9 |
| | ``` |
| | - Top k Sampling |
| | Sampling is a strategy to randomly choose the next word via the probability distribution instead of argmax. |
| | Therefore, Top k Sampling samples the word via distribution but restricted to top-k probable words. |
| | However, there is a problem when sampling the rarely used word, the sentence will not fluent. |
| | ``` |
| | k = 5 |
| | Top k Result(f1-score)：rouge-1: 4.0, rouge-2: 0.5, rouge-L: 3.7 |
| | ``` |
| | - Nucleus(Top p) Sampling |
| | Nucleus Sampling is sampling from a subset of vocabulary with the most probability mass. |
| | It can dynamically shrink and expand top-k. |
| | ``` |
| | p = 5 |
| | Top p Result(f1-score)：rouge-1: 3.0, rouge-2: 0.2, rouge-L: 2.9 |
| | ``` |
| | - Temperature |
| | softmax temperature is applying a temperature hyperparameter to the softmax. |
| | with high temperature： become more uniform, more diversity |
| | with low temperature：become more spiky, less diversity |
| | ``` |
| | temperature = 5 |
| | Temperature Result(f1-score)：rouge-1: 2.1, rouge-2: 0.04, rouge-L: 1.9 |
| | ``` |
| |
|
| | As the result, we can figure out that in this task, beam search outperforms other strategies. |
