Processing link structures and linkbases on the web Hyperlinks are an essential feature of the World Wide Web , highly responsible for its success . XLink improves on HTML 's linking capabilities in several ways . In particular , links after XLink can be `` out-of-line '' ( i.e. , not defined at a link source ) and collected in ( possibly several ) linkbases , which considerably ease building complex link structures . Modeling of link structures and processing of linkbases under the Web 's `` open world linking '' are aspects neglected by XLink . Adding a notion of `` interface '' to XLink , as suggested in this work , considerably improves modeling of link structures . When a link structure is traversed , the relevant linkbase ( s ) might become ambiguous . We suggest three linkbase management modes governing the binding of a linkbase to a document to resolve this ambiguity .

O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O B O O O O O O O O

electronic publishing
hyperlink
link modeling and processing


Answering approximate queries over autonomous web databases To deal with the problem of empty or too little answers returned from a Web database in response to a user query , this paper proposes a novel approach to provide relevant and ranked query results . Based on the user original query , we speculate how much the user cares about each specified attribute and assign a corresponding weight to it . This original query is then rewritten as an approximate query by relaxing the query criteria range . The relaxation order of all specified attributes and the relaxed degree on each specified attribute are varied with the attribute weights . For the approximate query results , we generate users ' contextual preferences from database workload and use them to create a priori orders of tuples in an off-line preprocessing step . Only a few representative orders are saved , each corresponding to a set of contexts . Then , these orders and associated contexts are used at query time to expeditiously provide ranked answers . Results of a preliminary user study demonstrate that our query relaxation and results ranking methods can capture the user 's preferences effectively . The efficiency and effectiveness of our approach is also demonstrated by experimental result .

O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O


Consideration set generation in commerce search In commerce search , the set of products returned by a search engine often forms the basis for all user interactions leading up to a potential transaction on the web . Such a set of products is known as the consideration set . In this study , we consider the problem of generating consideration set of products in commerce search so as to maximize user satisfaction . One of the key features of commerce search that we exploit in our study is the association of a set of important attributes with the products and a set of specified attributes with the user queries . Those important attributes not used in the query are treated as unspecified . The attribute space admits a natural definition of user satisfaction via user preferences on the attributes and their values , viz . require that the surfaced products be close to the specified attribute values in the query , and diverse with respect to the unspecified attributes . We model this as a general Max-Sum Dispersion problem wherein we are given a set of n nodes in a metric space and the objective is to select a subset of nodes with total cost at most a given budget , and maximize the sum of the pairwise distances between the selected nodes . In our setting , each node denotes a product , the cost of a node being inversely proportional to its relevance with respect to specified attributes . The distance between two nodes quantifies the diversity with respect to the unspecified attributes . The problem is NP-hard and a 2-approximation was previously known only when all the nodes have unit cost . In our setting , we do not make any assumptions on the cost . We label this problem as the General Max-Sum Dispersion problem . We give the first constant factor approximation algorithm for this problem , achieving an approximation ratio of 2 . Further , we perform extensive empirical analysis on real-world data to show the effectiveness of our algorithm .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

approximation algorithms
facility dispersion
information search and retrieval
novelty


A large-scale study of robots . txt Search engines largely rely on Web robots to collect information from the Web . Due to the unregulated open-access nature of the Web , robot activities are extremely diverse . Such crawling activities can be regulated from the server side by deploying the Robots Exclusion Protocol in a file called robots . txt . Although it is not an enforcement standard , ethical robots ( and many commercial ) will follow the rules specified in robots . txt . With our focused crawler , we investigate 7,593 websites from education , government , news , and business domains . Five crawls have been conducted in succession to study the temporal changes . Through statistical analysis of the data , we present a survey of the usage of Web robots rules at the Web scale . The results also show that the usage of robots . txt has increased over time .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Accelerated focused crawling through online relevance feedback The organization of HTML into a tag tree structure , which is rendered by browsers as roughly rectangular regions with embedded text and HREF links , greatly helps surfers locate and click on links that best satisfy their information need . Can an automatic program emulate this human behavior and thereby learn to predict the relevance of an unseen HREF target page w.r.t. an information need , based on information limited to the HREF source page ? Such a capability would be of great interest in focused crawling and resource discovery , because it can fine-tune the priority of unvisited URLs in the crawl frontier , and reduce the number of irrelevant pages which are fetched and discarded .

O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

document object model
hypertext/hypermedia
reinforcement learning


Summarization of online image collections via implicit feedback The availability of map interfaces and location-aware devices makes a growing amount of unstructured , geo-referenced information available on the Web . In particular , over twelve million geo-referenced photos are now available on Flickr , a popular photo-sharing website . We show a method to analyze the Flickr data and generate aggregate knowledge in the form of `` representative tags '' for arbitrary areas in the world . We display these tags on a map interface in an interactive web application along with images associated with each tag . We then use the implicit feedback of the aggregate user interactions with the tags and images to learn which images best describe the area shown on the map .

O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O

geo-referenced data
geotagged
image summarization
miscellaneous
photographs
tagging
visualization


A client-aware dispatching algorithm for web clusters providing multiple services

dispatching algorithms
distributed systems
load balancing


Online team formation in social networks We study the problem of online team formation . We consider a setting in which people possess different skills and compatibility among potential team members is modeled by a social network . A sequence of tasks arrives in an online fashion , and each task requires a specific set of skills . The goal is to form a new team upon arrival of each task , so that ( i ) each team possesses all skills required by the task , ( ii ) each team has small communication overhead , and ( iii ) the workload of performing the tasks is balanced among people in the fairest possible way . We propose efficient algorithms that address all these requirements : our algorithms form teams that always satisfy the required skills , provide approximation guarantees with respect to team communication overhead , and they are online-competitive with respect to load balancing . Experiments performed on collaboration networks among film actors and scientists , confirm that our algorithms are successful at balancing these conflicting requirements . This is the first paper that simultaneously addresses all these aspects . Previous work has either focused on minimizing coordination for a single task or balancing the workload neglecting coordination costs .

O B I O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Structured query suggestion for specialization and parallel movement : effect on search behaviors Query suggestion , which enables the user to revise a query with a single click , has become one of the most fundamental features of Web search engines . However , it is often difficult for the user to choose from a list of query suggestions , and to understand the relation between an input query and suggested ones . In this paper , we propose a new method to present query suggestions to the user , which has been designed to help two popular query reformulation actions , namely , specialization ( e.g. from `` nikon '' to `` nikon camera '' ) and parallel movement ( e.g. from `` nikon camera '' to `` canon camera '' ) . Using a query log collected from a popular commercial Web search engine , our prototype called SParQS classifies query suggestions into automatically generated categories and generates a label for each category . Moreover , SParQS presents some new entities as alternatives to the original query ( e.g. `` canon '' in response to the query `` nikon '' ) , together with their query suggestions classified in the same way as the original query 's suggestions . We conducted a task-based user study to compare SParQS with a traditional `` flat list '' query suggestion interface . Our results show that the SParQS interface enables subjects to search more successfully than the flat list case , even though query suggestions presented were exactly the same in the two interfaces . In addition , the subjects found the query suggestions more helpful when they were presented in the SParQS interface rather than in a flat list .

O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information search and retrieval
query log mining
search user interface


User-centric content freshness metrics for search engines In order to return relevant search results , a search engine must keep its local repository synchronized to the Web , but it is usually impossible to attain perfect freshness . Hence , it is vital for a production search engine continually to monitor and improve repository freshness . Most previous freshness metrics , formulated in the context of developing better synchronization policies , focused on the web crawler while ignoring other parts of a search engine . But , the freshness of documents in a web crawler does not necessarily translate directly into the freshness of search results as seen by users . We propose metrics for measuring freshness from a user 's perspective , which take into account the latency between when documents are crawled and when they are viewed by users , as well as the variation in user click and view frequency among different documents . We also describe a practical implementation of these metrics that were used in a production search engine .

O O B B O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B O O O O O O O O O B I O O O O O O B O O O B B O O O O O O O O O O O O O O O O O O O O O O B I O O O O B O O O O O O O O O O O O O B O O O O O O O O O O B O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O B I O


Towards lightweight and efficient DDOS attacks detection for web server In this poster , based on our previous work in building a lightweight DDoS ( Distributed Denial-of-Services ) attacks detection mechanism for web server using TCM-KNN ( Transductive Confidence Machines for K-Nearest Neighbors ) and genetic algorithm based instance selection methods , we further propose a more efficient and effective instance selection method , named E-FCM ( Extend Fuzzy C-Means ) . By using this method , we can obtain much cheaper training time for TCM-KNN while ensuring high detection performance . Therefore , the optimized mechanism is more suitable for lightweight DDoS attacks detection in real network environment .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

e-fcm algorithm
security and protection
tcm-knn algorithm
web server anomaly detection


Ensuring required failure atomicity of composite Web services The recent evolution of Internet , driven by the Web services technology , is extending the role of the Web from a support of information interaction to a middleware for B2B interactions . Indeed , the Web services technology allows enterprises to outsource parts of their business processes using Web services . And it also provides the opportunity to dynamically offer new value-added services through the composition of pre-existing Web services . In spite of the growing interest in Web services , current technologies are found lacking efficient transactional support for composite Web services ( CSs ) . In this paper , we propose a transactional approach to ensure the failure atomicity , of a CS , required by partners . We use the Accepted Termination States ( ATS ) property as a mean to express the required failure atomicity . Partners specify their CS , mainly its control flow , and the required ATS . Then , we use a set of transactional rules to assist designers to compose a valid CS with regards to the specified ATS .

O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

reliable web services compositions
transactional models


Optimized query planning of continuous aggregation queries in dynamic data dissemination networks Continuous queries are used to monitor changes to time varying data and to provide results useful for online decision making . Typically a user desires to obtain the value of some aggregation function over distributed data items , for example , to know ( a ) the average of temperatures sensed by a set of sensors ( b ) the value of index of mid-cap stocks . In these queries a client specifies a coherency requirement as part of the query . In this paper we present a low-cost , scalable technique to answer continuous aggregation queries using a content distribution network of dynamic data items . In such a network of data aggregators , each data aggregator serves a set of data items at specific coherencies . Just as various fragments of a dynamic web-page are served by one or more nodes of a content distribution network , our technique involves decomposing a client query into sub-queries and executing sub-queries on judiciously chosen data aggregators with their individual sub-query incoherency bounds . We provide a technique of getting the optimal query plan ( i.e. , set of sub-queries and their chosen data aggregators ) which satisfies client query . s coherency requirement with least cost , measured in terms of the number of refresh messages sent from aggregators to the client . For estimating query execution cost , we build a continuous query cost model which can be used to estimate the number of messages required to satisfy the client specified incoherency bound . Performance results using real-world traces show that our cost based query planning leads to queries being executed using less than one third the number of messages required by existing schemes .

O O O O B I I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

continuous aggregation queries
dynamic data

content distribution networks
data coherency
query dissemination cost


Evaluation of edge caching\/offloading for dynamic content delivery As dynamic content becomes increasingly dominant , it becomes an important research topic as how the edge resources such as client-side proxies , which are otherwise underutilized for such content , can be put into use . However , it is unclear what will be the best strategy and the design\/deployment tradeoffs lie therein . In this paper , using one representative e-commerce benchmark , we report our experience of an extensive investigation of different offloading and caching options . Our results point out that , while great benefits can be reached in general , advanced offloading strategies can be overly complex and even counter-productive . In contrast , simple augmentation at proxies to enable fragment caching and page composition achieves most of the benefit without compromising important considerations such as security .

O O O O O B I O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Crowdsourcing with endogenous entry We investigate the design of mechanisms to incentivize high quality outcomes in crowdsourcing environments with strategic agents , when entry is an endogenous , strategic choice . Modeling endogenous entry in crowdsourcing markets is important because there is a nonzero cost to making a contribution of any quality which can be avoided by not participating , and indeed many sites based on crowdsourced content do not have adequate participation . We use a mechanism with monotone , rank-based , rewards in a model where agents strategically make participation and quality choices to capture a wide variety of crowdsourcing environments , ranging from conventional crowdsourcing contests with monetary rewards such as TopCoder , to crowdsourced content as in online Q&A forums . We begin by explicitly constructing the unique mixed-strategy equilibrium for such monotone rank-order mechanisms , and use the participation probability and distribution of qualities from this construction to address the question of designing incentives for two kinds of rewards that arise in the context of crowdsourcing . We first show that for attention rewards that arise in the crowdsourced content setting , the entire equilibrium distribution and therefore every increasing statistic including the maximum and average quality ( accounting for participation ) , improves when the rewards for every rank but the last are as high as possible . In particular , when the cost of producing the lowest possible quality content is low , the optimal mechanism displays all but the poorest contribution . We next investigate how to allocate rewards in settings where there is a fixed total reward that can be arbitrarily distributed amongst participants , as in crowdsourcing contests . Unlike models with exogenous entry , here the expected number of participants can be increased by subsidizing entry , which could potentially improve the expected value of the best contribution . However , we show that subsidizing entry does not improve the expected quality of the best contribution , although it may improve the expected quality of the average contribution . In fact , we show that free entry is dominated by taxing entry -- making all entrants pay a small fee , which is rebated to the winner along with whatever rewards were already assigned , can improve the quality of the best contribution over a winner-take-all contest with no taxes .

B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

contest design
game theory
mechanism design
social computing
user generated content


Image

annotation

using

clickthrough

data

Automatic

image

annotation

using

supervised

learning

is

performed

by

concept

classifiers

trained

on

labeled

example

images

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use

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clickthrough

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search

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source

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the

automatic

generation

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concept

training

data

thus

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the

expensive

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this

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photographic

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http:\/\/olympus.ee.auth.gr\/~diou\/civr2009\/

B I O B I O B I O B I O O O O O O O O O O O O O O O O O B I O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

clickthrough data
image annotation
search logs
supervised learning

collective knowledge
concepts
content analysis and indexing
implicit feedback


U-REST : an unsupervised record extraction system In this paper , we describe a system that can extract recordstructures from web pages with no direct human supervision . Records are commonly occurring HTML-embedded data tuples that describe people , offered courses , products , company profiles , etc. . We present a simplified frameworkfor studying the problem of unsupervised record extraction . one which separates the algorithms from the feature engineering . Our system , U-REST formalizes an approach tothe problem of unsupervised record extraction using a simple two-stage machine learning framework . The first stage involves clustering , where structurally similar regions are discovered , and the second stage involves classification , where discovered groupings ( clusters of regions ) are ranked by their likelihood of being records . In our work , we describe , and summarize the results of an extensive survey of features for both stages . We conclude by comparing U-REST to related systems . The results of our empirical evaluation show encouraging improvements in extraction accuracy .

O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


A framework for rapid integration of presentation components The development of user interfaces ( UIs ) is one of the most time-consuming aspects in software development . In this context , the lack of proper reuse mechanisms for UIs is increasingly becoming manifest , especially as software development is more and more moving toward composite applications . In this paper we propose a framework for the integration of stand-alone modules or applications , where integration occurs at the presentation layer . Hence , the final goal is to reduce the effort required for UI development by maximizing reus . The design of the framework is inspired by lessons learned from application integration , appropriately modified to account for the specificity of the UI integration problem . We provide an abstract component model to specify characteristics and behaviors of presentation components and propose an event-based composition model to specify the composition logic . Components and composition are described by means of a simple XML-based language , which is interpreted by a runtime middleware for the execution of the resulting composite application . A proof-of-concept prototype allows us to show that the proposed component model can also easily be applied to existing presentation components , built with different languages and\/or component technologies .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O

graphical user interfaces
interaction styles
presentation component
presentation composition
presentation integration
user interface
xpil


Predictive caching and prefetching of query results in search engines We study the caching of query result pages in Web search engines . Popular search engines receive millions of queries per day , and efficient policies for caching query results may enable them to lower their response time and reduce their hardware requirements . We present PDC ( probability driven cache ) , a novel scheme tailored for caching search results , that is based on a probabilistic model of search engine users . We then use a trace of over seven million queries submitted to the search engine AltaVista to evaluate PDC , as well as traditional LRU and SLRU based caching schemes . The trace driven simulations show that PDC outperforms the other policies . We also examine the prefetching of search results , and demonstrate that prefetching can increase cache hit ratios by 50 % for large caches , and can double the hit ratios of small caches . When integrating prefetching into PDC , we attain hit ratios of over 0.53 .

O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information storage and retrieval
query processing and optimization


Efficient overlap and content reuse detection in blogs and online news articles The use of blogs to track and comment on real world ( political , news , entertainment ) events is growing . Similarly , as more individuals start relying on the Web as their primary information source and as more traditional media outlets try reaching consumers through alternative venues , the number of news sites on the Web is also continuously increasing . Content-reuse , whether in the form of extensive quotations or content borrowing across media outlets , is very common in blogs and news entries outlets tracking the same real-world event . Knowledge about which web entries re-use content from which others can be an effective asset when organizing these entries for presentation . On the other hand , this knowledge is not cheap to acquire : considering the size of the related space web entries , it is essential that the techniques developed for identifying re-use are fast and scalable . Furthermore , the dynamic nature of blog and news entries necessitates incremental processing for reuse detection . In this paper , we develop a novel qSign algorithm that efficiently and effectively analyze the blogosphere for quotation and reuse identification . Experiment results show that with qSign processing time gains from 10X to 100X are possible while maintaining reuse detection rates of upto 90 % . Furthermore , processing time gains can be pushed multiple orders of magnitude ( from 100X to 1000X ) for 70 % recall .

O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information search and retrieval
weblogs


Jena : implementing the semantic web recommendations The new Semantic Web recommendations for RDF , RDFS and OWL have , at their heart , the RDF graph . Jena2 , a second-generation RDF toolkit , is similarly centered on the RDF graph . RDFS and OWL reasoning are seen as graph-to-graph transforms , producing graphs of virtual triples . Rich APIs are provided . The Model API includes support for other aspects of the RDF recommendations , such as containers and reification . The Ontology API includes support for RDFS and OWL , including advanced OWL Full support . Jena includes the de facto reference RDF\/XML parser , and provides RDF\/XML output using the full range of the rich RDF\/XML grammar . N3 I\/O is supported . RDF graphs can be stored in-memory or in databases . Jena 's query language , RDQL , and the Web API are both offered for the next round of standardization .

B O O O B I O O O B I O O B O O O B O O O O O O O B O O O O O O B O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O B O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O


An application server for the semantic web The Semantic Web relies on the complex interaction of several technologies involving ontologies . Therefore , sophisticated Semantic Web applications typically comprise more than one software module . Instead of coming up with proprietary solutions , developers should be able to rely on a generic infrastructure for application development in this context . We call such an infrastructure Application Server for the Semantic Web whose design and development are based on existing Application Servers . However , we apply and augment their underlying concepts for use in the Semantic Web and integrate semantic technology within the server itself . We provide a short overview of requirements and design issues of such a server and present our implementation and ongoing work KAON SERVER .

O B I O O B I O B I O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


A flight meta-search engine with metamorph We demonstrate a flight meta-search engine that is based on the Metamorph framework . Metamorph provides mechanisms to model web forms together with the interactions which are needed to fulfil a request , and can generate interaction sequences that pose queries using these web forms and collect the results . In this paper , we discuss an interesting new feature that makes use of the forms themselves as an information source . We show how data can be extracted from web forms ( rather than the data behind web forms ) to generate a graph of flight connections between cities . The flight connection graph allows us to vastly reduce the number of queries that the engine sends to airline websites in the most interesting search scenarios ; those that involve the controversial practice of creative ticketing , in which agencies attempt to find lower price fares by using more than one airline for a journey . We describe a system which attains data from a number of websites to identify promising routes and prune the search tree . Heuristics that make use of geographical information and an estimation of cost based on historical data are employed . The results are then made available to improve the quality of future search requests .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

hidden web
systems and software
web data extraction
web form extraction
web form mapping


Leveraging user comments for aesthetic aware image search reranking The increasing number of images available online has created a growing need for efficient ways to search for relevant content . Text-based query search is the most common approach to retrieve images from the Web . In this approach , the similarity between the input query and the metadata of images is used to find relevant information . However , as the amount of available images grows , the number of relevant images also increases , all of them sharing very similar metadata but differing in other visual characteristics . This paper studies the influence of visual aesthetic quality in search results as a complementary attribute to relevance . By considering aesthetics , a new ranking parameter is introduced aimed at improving the quality at the top ranks when large amounts of relevant results exist . Two strategies for aesthetic rating inference are proposed : one based on visual content , another based on the analysis of user comments to detect opinions about the quality of images . The results of a user study with $ 58 $ participants show that the comment-based aesthetic predictor outperforms the visual content-based strategy , and reveals that aesthetic-aware rankings are preferred by users searching for photographs on the Web .

O B I O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information search and retrieval
multimedia information systems
opinion mining
sentiment analysis
visual aesthetics modeling


CWS : a comparative web search system In this paper , we define and study a novel search problem : Comparative Web Search ( CWS ) . The task of CWS is to seek relevant and comparative information from the Web to help users conduct comparisons among a set of topics . A system called CWS is developed to effectively facilitate Web users ' comparison needs . Given a set of queries , which represent the topics that a user wants to compare , the system is characterized by : ( 1 ) automatic retrieval and ranking of Web pages by incorporating both their relevance to the queries and the comparative contents they contain ; ( 2 ) automatic clustering of the comparative contents into semantically meaningful themes ; ( 3 ) extraction of representative keyphrases to summarize the commonness and differences of the comparative contents in each theme . We developed a novel interface which supports two types of view modes : a pair-view which displays the result in the page level , and a cluster-view which organizes the comparative pages into the themes and displays the extracted phrases to facilitate users ' comparison . Experiment results show the CWS system is effective and efficient .

O O O B I I O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information search and retrieval
keyphrase extraction
on-line information services
search engine


A self organizing document map algorithm for large scale hyperlinked data inspired by neuronal migration Web document clustering is one of the research topics that is being pursued continuously due to the large variety of applications . Since Web documents usually have variety and diversity in terms of domains , content and quality , one of the technical difficulties is to find a reasonable number and size of clusters . In this research , we pay attention to SOMs ( Self Organizing Maps ) because of their capability of visualized clustering that helps users to investigate characteristics of data in detail . The SOM is widely known as a `` scalable '' algorithm because of its capability to handle large numbers of records . However , it is effective only when the vectors are small and dense . Although several research efforts on making the SOM scalable have been conducted , technical issues on scalability and performance for sparse high-dimensional data such as hyperlinked documents still remain . In this paper , we introduce MIGSOM , an SOM algorithm inspired by a recent discovery on neuronal migration . The two major advantages of MIGSOM are its scalability for sparse high-dimensional data and its clustering visualization functionality . In this paper , we describe the algorithm and implementation , and show the practicality of the algorithm by applying MIGSOM to a huge scale real data set : Wikipedia 's hyperlink data .

O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O


Web page summarization using dynamic content Summarizing web pages have recently gained much attention from researchers . Until now two main types of approaches have been proposed for this task : content - and context-based methods . Both of them assume fixed content and characteristics of web documents without considering their dynamic nature . However the volatility of information published on the Internet argue for the implementation of more time-aware techniques . This paper proposes a new approach towards automatic web page description , which extends the concept of a web page by the temporal dimension . Our method provides a broader view on web document summarization and can complement the existing techniques .

B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O


Compiling XSLT 2.0 into XQuery 1.0 As XQuery is gathering momentum as the standard query language for XML , there is a growing interest in using it as an integral part of the XML application development infrastructure . In that context , one question which is often raised is how well XQuery interoperates with other XML languages , and notably with XSLT . XQuery 1.0 ( 16 ) and XSLT 2.0 ( 7 ) share a lot in common : they share XPath 2.0 as a common sub-language and have the same expressiveness . However , they are based on fairly different programming paradigms . While XSLT has adopted a highly declarative template based approach , XQuery relies on a simpler , and more operational , functional approach . In this paper , we present an approach to compile XSLT 2.0 into XQuery 1.0 , and a working implementation of that approach . The compilation rules explain how XSLT 's template-based approach can be implemented using the functional approach of XQuery and underpins the tight connection between the two languages . The resulting compiler can be used to migrate a XSLT code base to XQuery , or to enable the use of XQuery runtimes ( e.g. , as will soon be provided by most relational database management systems ) for XSLT users . We also identify a number of areas where compatibility between the two languages could be improved . Finally , we show experiments on actual XSLT stylesheets , demonstrating the applicability of the approach in practice .

O B O O B O O B O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O B O O O O O B O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O


The case for multi-user design for computer aided learning in developing regions Computer-aided learning is fast gaining traction in developing regions as a means to augment classroom instruction . Reasons for using computer-aided learning range from supplementing teacher shortages to starting underprivileged children off in technology , and funding for such initiatives range from state education funds to international agencies and private groups interested in child development . The interaction of children with computers is seen at various levels , from unsupervised self-guided learning at public booths without specific curriculum to highly regulated in-class computer applications with modules designed to go with school curriculum . Such learning is used at various levels from children as young as 5 year-old to high-schoolers . This paper uses field observations of primary school children in India using computer-aided learning modules , and finds patterns by which children who perform better in classroom activities seat themselves in front of computer monitors , and control the mouse , in cases where children are required to share computer resources . We find that in such circumstances , there emerges a pattern of learning , unique to multi-user environments - wherein certain children tend to learn better because of their control of the mouse . This research also shows that while computer aided learning software for children is primarily designed for single-users , the implementation realities of resource-strapped learning environments in developing regions presents a strong case for multi-user design .

O O O O O O O O O O B I O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O


Predicting clicks : estimating the click-through rate for new ads Search engine advertising has become a significant element of the Web browsing experience . Choosing the right ads for the query and the order in which they are displayed greatly affects the probability that a user will see and click on each ad . This ranking has a strong impact on the revenue the search engine receives from the ads . Further , showing the user an ad that they prefer to click on improves user satisfaction . For these reasons , it is important to be able to accurately estimate the click-through rate of ads in the system . For ads that have been displayed repeatedly , this is empirically measurable , but for new ads , other means must be used . We show that we can use features of ads , terms , and advertisers to learn a model that accurately predicts the click-though rate for new ads . We also show that using our model improves the convergence and performance of an advertising system . As a result , our model increases both revenue and user satisfaction .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

click-through rate
cpc
ctr
information search and retrieval
learning
paid search
sponsored search
web advertising


Composite events for xml Recently , active behavior has received attention in the XML field to automatically react to occurred events . Aside from proprietary approaches for enriching XML with active behavior , the W3C standardized the Document Object Model ( DOM ) Event Module for the detection of events in XML documents . When using any of these approaches , however , it is often impossible to decide which event to react upon because not a single event but a combination of multiple events , i.e. , a composite event determines a situation to react upon . The paper presents the first approach for detecting composite events in XML documents by addressing the peculiarities of XML events which are caused by their hierarchical order in addition to their temporal order . It also provides for the detection of satisfied multiplicity constraints defined by XML schemas . Thereby the approach enables applications operating on XML documents to react to composite events which have richer semantics .

O O O B O O B I O O O O O B O O O O O O O O O O O O O O B O B I O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O

event algebra
event-condition-action rule


Distributed web retrieval In the ocean of Web data , Web search engines are the primary way to access content . As the data is on the order of petabytes , current search engines are very large centralized systems based on replicated clusters . Web data , however , is always evolving . The number of Web sites continues to grow rapidly ( over 270 millions at the beginning of 2011 ) and there are currently more than 20 billion indexed pages . On the other hand , Internet users are above one billion and hundreds of million of queries are issued each day . In the near future , centralized systems are likely to become less effective against such a data-query load , thus suggesting the need of fully distributed search engines . Such engines need to maintain high quality answers , fast response time , high query throughput , high availability and scalability ; in spite of network latency and scattered data . In this tutorial we present the architecture of current search engines and we explore the main challenges behind the design of all the processes of a distributed Web retrieval system crawling , indexing , and query processing .

O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O B I O

crawling
indexing
query processing
web search


AdHeat : an influence-based diffusion model for propagating hints to match ads In this paper , we present AdHeat , a social ad model considering user influence in addition to relevance for matching ads . Traditionally , ad placement employs the relevance model . Such a model matches ads with Web page content , user interests , or both . We have observed , however , on social networks that the relevance model suffers from two shortcomings . First , influential users ( users who contribute opinions ) seldom click ads that are highly relevant to their expertise . Second , because influential users ' contents and activities are attractive to other users , hint words summarizing their expertise and activities may be widely preferred . Therefore , we propose AdHeat , which diffuses hint words of influential users to others and then matches ads for each user with aggregated hints . We performed experiments on a large online Q&A community with half a million users . The experimental results show that AdHeat outperforms the relevance model on CTR ( click through rate ) by significant margins .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

behavior targeting
contextual advertising
heat diffusion
influence propagation
online advertising
social network analysis


Querying for meta knowledge The Semantic Web is based on accessing and reusing RDF data from many different sources , which one may assign different levels of authority and credibility . Existing Semantic Web query languages , like SPARQL , have targeted the retrieval , combination and reuse of facts , but have so far ignored all aspects of meta knowledge , such as origins , authorship , recency or certainty of data , to name but a few . In this paper , we present an original , generic , formalized and implemented approach for managing many dimensions of meta knowledge , like source , authorship , certainty and others . The approach re-uses existing RDF modeling possibilities in order to represent meta knowledge . Then , it extends SPARQL query processing in such a way that given a SPARQL query for data , one may request meta knowledge without modifying the original query . Thus , our approach achieves highly flexible and automatically coordinated querying for data and meta knowledge , while completely separating the two areas of concern .

O O O O O B I O O O O O O B O O O O O O O O O O O O O O O O O O B I O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Large-scale text categorization by batch mode active learning Large-scale text categorization is an important research topic for Web data mining . One of the challenges in large-scale text categorization is how to reduce the human efforts in labeling text documents for building reliable classification models . In the past , there have been many studies on applying active learning methods to automatic text categorization , which try to select the most informative documents for labeling manually . Most of these studies focused on selecting a single unlabeled document in each iteration . As a result , the text categorization model has to be retrained after each labeled document is solicited . In this paper , we present a novel active learning algorithm that selects a batch of text documents for labeling manually in each iteration . The key of the batch mode active learning is how to reduce the redundancy among the selected examples such that each example provides unique information for model updating . To this end , we use the Fisher information matrix as the measurement of model uncertainty and choose the set of documents to effectively maximize the Fisher information of a classification model . Extensive experiments with three different datasets have shown that our algorithm is more effective than the state-of-the-art active learning techniques for text categorization and can be a promising tool toward large-scale text categorization for World Wide Web documents .

O B I O O O B I O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I O O B I O O O O O O O O B I O O O O O O

active learning
fisher information
text categorization

convex optimization
information search and retrieval
logistic regression


Human wayfinding in information networks Navigating information spaces is an essential part of our everyday lives , and in order to design efficient and user-friendly information systems , it is important to understand how humans navigate and find the information they are looking for . We perform a large-scale study of human wayfinding , in which , given a network of links between the concepts of Wikipedia , people play a game of finding a short path from a given start to a given target concept by following hyperlinks . What distinguishes our setup from other studies of human Web-browsing behavior is that in our case people navigate a graph of connections between concepts , and that the exact goal of the navigation is known ahead of time . We study more than 30,000 goal-directed human search paths and identify strategies people use when navigating information spaces . We find that human wayfinding , while mostly very efficient , differs from shortest paths in characteristic ways . Most subjects navigate through high-degree hubs in the early phase , while their search is guided by content features thereafter . We also observe a trade-off between simplicity and efficiency : conceptually simple solutions are more common but tend to be less efficient than more complex ones . Finally , we consider the task of predicting the target a user is trying to reach . We design a model and an efficient learning algorithm . Such predictive models of human wayfinding can be applied in intelligent browsing interfaces .

O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O


Cooperative leases : scalable consistency maintenance in content distribution networks In this paper , we argue that cache consistency mechanisms designed for stand-alone proxies do not scale to the large number of proxies in a content distribution network and are not flexible enough to allow consistency guarantees to be tailored to object needs . To meet the twin challenges of scalability and flexibility , we introduce the notion of cooperative consistency along with a mechanism , called cooperative leases , to achieve it . By supporting & Dgr ; - consistency semantics and by using a single lease for multiple proxies , cooperative leases allows the notion of leases to be applied in a flexible , scalable manner to CDNs . Further , the approach employs application-level multicast to propagate server notifications to proxies in a scalable manner . We implement our approach in the Apache web server and the Squid proxy cache and demonstrate its efficacy using a detailed experimental evaluation . Our results show a factor of 2.5 reduction in server message overhead and a 20 % reduction in server state space overhead when compared to original leases albeit at an increased inter-proxy communication overhead .

O B O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O

content distribution networks
leases
scalability

data consistency
data dissemination
dynamic data
pullc
push
world wide web


Text-based video blogging A video blogging system has been developed for easily producing your own video programs that can be made available to the public in much the same way that blogs are created . The user merely types a program script on a webpage , the same as creating a blog , selects a direction style , and pastes in some additional material content to create a CG-based video program that can be openly distributed to the general public . The script , direction style , and material content are automatically combined to create a movie file on the server side . The movie file can then be accessed by referring to an RSS feed and viewed on the screens of various devices .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


G-ToPSS : fast filtering of graph-based metadata RDF is increasingly being used to represent metadata . RDF Site Summary ( RSS ) is an application of RDF on the Web that has considerably grown in popularity . However , the way RSS systems operate today does not scale well . In this paper we introduce G-ToPSS , a scalable publish\/subscribe system for selective information dissemination . G-ToPSS is particularly well suited for applications that deal with large-volume content distribution from diverse sources . RSS is an instance of the content distribution problem . G-ToPSS allows use of ontology as a way to provide additional information about the data . Furthermore , in this paper we show how G-ToPSS can support RDFS class taxonomies . We have implemented and experimentally evaluated G-ToPSS and we provide results in the paper demonstrating its scalability compared to alternatives .

O O O O O O O B O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

content-based routing
graph matching
information search and retrieval
publish/subscribe
systems and software


Scalable techniques for document identifier assignment in inverted indexes Web search engines depend on the full-text inverted index data structure . Because the query processing performance is so dependent on the size of the inverted index , a plethora of research has focused on fast end effective techniques for compressing this structure . Recently , several authors have proposed techniques for improving index compression by optimizing the assignment of document identifiers to the documents in the collection , leading to significant reduction in overall index size . In this paper , we propose improved techniques for document identifier assignment . Previous work includes simple and fast heuristics such as sorting by URL , as well as more involved approaches based on the Traveling Salesman Problem or on graph partitioning . These techniques achieve good compression but do not scale to larger document collections . We propose a new framework based on performing a Traveling Salesman computation on a reduced sparse graph obtained through Locality Sensitive Hashing . This technique achieves improved compression while scaling to tens of millions of documents . Based on this framework , we describe a number of new algorithms , and perform a detailed evaluation on three large data sets showing improvements in index size .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Measurement-calibrated graph models for social network experiments Access to realistic , complex graph datasets is critical to research on social networking systems and applications . Simulations on graph data provide critical evaluation of new systems and applications ranging from community detection to spam filtering and social web search . Due to the high time and resource costs of gathering real graph datasets through direct measurements , researchers are anonymizing and sharing a small number of valuable datasets with the community . However , performing experiments using shared real datasets faces three key disadvantages : concerns that graphs can be de-anonymized to reveal private information , increasing costs of distributing large datasets , and that a small number of available social graphs limits the statistical confidence in the results . The use of measurement-calibrated graph models is an attractive alternative to sharing datasets . Researchers can `` fit '' a graph model to a real social graph , extract a set of model parameters , and use them to generate multiple synthetic graphs statistically similar to the original graph . While numerous graph models have been proposed , it is unclear if they can produce synthetic graphs that accurately match the properties of the original graphs . In this paper , we explore the feasibility of measurement-calibrated synthetic graphs using six popular graph models and a variety of real social graphs gathered from the Facebook social network ranging from 30,000 to 3 million edges . We find that two models consistently produce synthetic graphs with common graph metric values similar to those of the original graphs . However , only one produces high fidelity results in our application-level benchmarks . While this shows that graph models can produce realistic synthetic graphs , it also highlights the fact that current graph metrics remain incomplete , and some applications expose graph properties that do not map to existing metrics .

O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Comparative study of clustering techniques for short text documents We compare various document clustering techniques including K-means , SVD-based method and a graph-based approach and their performance on short text data collected from Twitter . We define a measure for evaluating the cluster error with these techniques . Observations show that graph-based approach using affinity propagation performs best in clustering short text data with minimal cluster error .

O O O O O O B I O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O B I O O O O O O


Truthy : mapping the spread of astroturf in microblog streams Online social media are complementing and in some cases replacing person-to-person social interaction and redefining the diffusion of information . In particular , microblogs have become crucial grounds on which public relations , marketing , and political battles are fought . We demonstrate a web service that tracks political memes in Twitter and helps detect astroturfing , smear campaigns , and other misinformation in the context of U.S. political elections . We also present some cases of abusive behaviors uncovered by our service . Our web service is based on an extensible framework that will enable the real-time analysis of meme diffusion in social media by mining , visualizing , mapping , classifying , and modeling massive streams of public microblogging events .

B O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O

memes
microblogs
social media
truthy
twitter

classification
information diffusion
politics


XML-based XML schema access XML Schema 's abstract data model consists of components , which are the structures that eventually define a schema as a whole . XML Schema 's XML syntax , on the other hand , is not a direct representation of the schema components , and it proves to be surprisingly hard to derive a schema 's components from the XML syntax . The Schema Component XML Syntax ( SCX ) is a representation which attempts to map schema components as faithfully as possible to XML structures . SCX serves as the starting point for applications which need access to schema components and want to do so using standardized and widely available XML technologies .

O B O O B O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O B O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O B O O


Limiting the spread of misinformation in social networks In this work , we study the notion of competing campaigns in a social network and address the problem of influence limitation where a `` bad '' campaign starts propagating from a certain node in the network and use the notion of limiting campaigns to counteract the effect of misinformation . The problem can be summarized as identifying a subset of individuals that need to be convinced to adopt the competing ( or `` good '' ) campaign so as to minimize the number of people that adopt the `` bad '' campaign at the end of both propagation processes . We show that this optimization problem is NP-hard and provide approximation guarantees for a greedy solution for various definitions of this problem by proving that they are submodular . We experimentally compare the performance of the greedy method to various heuristics . The experiments reveal that in most cases inexpensive heuristics such as degree centrality compare well with the greedy approach . We also study the influence limitation problem in the presence of missing data where the current states of nodes in the network are only known with a certain probability and show that prediction in this setting is a supermodular problem . We propose a prediction algorithm that is based on generating random spanning trees and evaluate the performance of this approach . The experiments reveal that using the prediction algorithm , we are able to tolerate about 90 % missing data before the performance of the algorithm starts degrading and even with large amounts of missing data the performance degrades only to 75 % of the performance that would be achieved with complete data .

O O O O B O B I O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

competing campaigns
misinformation
social networks

information cascades
nonnumerical algorithms and problems
submodular functions
supermodular functions


Web object retrieval The primary function of current Web search engines is essentially relevance ranking at the document level . However , myriad structured information about real-world objects is embedded in static Web pages and online Web databases . Document-level information retrieval can unfortunately lead to highly inaccurate relevance ranking in answering object-oriented queries . In this paper , we propose a paradigm shift to enable searching at the object level . In traditional information retrieval models , documents are taken as the retrieval units and the content of a document is considered reliable . However , this reliability assumption is no longer valid in the object retrieval context when multiple copies of information about the same object typically exist . These copies may be inconsistent because of diversity of Web site qualities and the limited performance of current information extraction techniques . If we simply combine the noisy and inaccurate attribute information extracted from different sources , we may not be able to achieve satisfactory retrieval performance . In this paper , we propose several language models for Web object retrieval , namely an unstructured object retrieval model , a structured object retrieval model , and a hybrid model with both structured and unstructured retrieval features . We test these models on a paper search engine and compare their performances . We conclude that the hybrid model is the superior by taking into account the extraction errors at varying levels .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information extraction
information retrieval


Tag-oriented document summarization Social annotations on a Web document are highly generalized description of topics contained in that page . Their tagged frequency indicates the user attentions with various degrees . This makes annotations a good resource for summarizing multiple topics in a Web page . In this paper , we present a tag-oriented Web document summarization approach by using both document content and the tags annotated on that document . To improve summarization performance , a new tag ranking algorithm named EigenTag is proposed in this paper to reduce noise in tags . Meanwhile , association mining technique is employed to expand tag set to tackle the sparsity problem . Experimental results show our tag-oriented summarization has a significant improvement over those not using tags .

O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O


WebViews : accessing personalized web content and services

content transcoding
dynamic content
electronic commerce
information delivery
personalization
portable devices
smart bookmarks
voice interfaces
web clipping
wrappers


Constructing folksonomies from user-specified relations on flickr Automatic folksonomy construction from tags has attracted much attention recently . However , inferring hierarchical relations between concepts from tags has a drawback in that it is difficult to distinguish between more popular and more general concepts . Instead of tags we propose to use user-specified relations for learning folksonomy . We explore two statistical frameworks for aggregating many shallow individual hierarchies , expressed through the collection\/set relations on the social photosharing site Flickr , into a common deeper folksonomy that reflects how a community organizes knowledge . Our approach addresses a number of challenges that arise while aggregating information from diverse users , namely noisy vocabulary , and variations in the granularity level of the concepts expressed . Our second contribution is a method for automatically evaluating learned folksonomy by comparing it to a reference taxonomy , e.g. , the Web directory created by the Open Directory Project . Our empirical results suggest that user-specified relations are a good source of evidence for learning folksonomies .

O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O

collective knowledge
social information processing
taxonomies


GIO : a semantic web application using the information grid framework It is well understood that the key for successful Semantic Web applications depends on the availability of machine understandable meta-data . We describe the Information Grid , a practical approach to the Semantic Web , and show a prototype implementation . Information grid resources span all the data in the organization and all the metadata required to make it meaningful . The final goal is to let organizations view their assets in a smooth continuum from the Internet to the Intranet , with uniform semantically rich access .

O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

browsing
databases
information visualization
meta-data
rdf
search
tools
user interface


Association search in semantic web : search + inference Association search is to search for certain instances in semantic web and then make inferences from and about the instances we have found . In this paper , we propose the problem of association search and our preliminary solution for it using Bayesian network . We first minutely define the association search and its categorization . We then define tasks in association search . In terms of Bayesian network , we take ontology taxonomy as network structure in Bayesian network . We use the query log of instances to estimate the network parameters . After the Bayesian network is constructed , we give the solution for association search in the network .

O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B I O O O B O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O


Probabilistic models for discovering e-communities The increasing amount of communication between individuals in e-formats ( e.g. email , Instant messaging and the Web ) has motivated computational research in social network analysis ( SNA ) . Previous work in SNA has emphasized the social network ( SN ) topology measured by communication frequencies while ignoring the semantic information in SNs . In this paper , we propose two generative Bayesian models for semantic community discovery in SNs , combining probabilistic modeling with community detection in SNs . To simulate the generative models , an EnF-Gibbs sampling algorithm is proposed to address the efficiency and performance problems of traditional methods . Experimental studies on Enron email corpus show that our approach successfully detects the communities of individuals and in addition provides semantic topic descriptions of these communities .

O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B I O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O

clustering
data mining
gibbs sampling
learning
statistical modeling


Support concepts for Web navigation : a cognitive engineering approach

network user interface
usability
world wide web


Surfing the web by site We provide a system for surfing the web at a high level of abstraction , which is an analogy of the web browser , but which displays entire sites at a time . It allows a principled investigation of what is present , based on an overview of all available information . We show a site 's relation to other sites , the broad nature of the information contained and how it is structured , and how it has changed over time . Our current system maintains a continuously updated archive of 40 million sites representing 1.9 billion web pages , and enables real-time navigation through the sea of web sites .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

large scale systems
novel browsing paradigms
web navigation strategies


Exploring web scale language models for search query processing It has been widely observed that search queries are composed in a very different style from that of the body or the title of a document . Many techniques explicitly accounting for this language style discrepancy have shown promising results for information retrieval , yet a large scale analysis on the extent of the language differences has been lacking . In this paper , we present an extensive study on this issue by examining the language model properties of search queries and the three text streams associated with each web document : the body , the title , and the anchor text . Our information theoretical analysis shows that queries seem to be composed in a way most similar to how authors summarize documents in anchor texts or titles , offering a quantitative explanation to the observations in past work . We apply these web scale n-gram language models to three search query processing ( SQP ) tasks : query spelling correction , query bracketing and long query segmentation . By controlling the size and the order of different language models , we find that the perplexity metric to be a good accuracy indicator for these query processing tasks . We show that using smoothed language models yields significant accuracy gains for query bracketing for instance , compared to using web counts as in the literature . We also demonstrate that applying web-scale language models can have marked accuracy advantage over smaller ones .

O O O B I O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O

information search and retrieval
very large-scale experiments
web n-gram


Practical semantic analysis of web sites and documents As Web sites are now ordinary products , it is necessary to explicit the notion of quality of a Web site . The quality of a site may belinked to the easiness of accessibility and also to other criteria such as the fact that the site is up to date and coherent . This last quality is difficult to insure because sites may be updated very frequently , may have many authors , may be partially generated and inthis context proof-reading is very difficult . The same piece of information may be found in different occurrences , but also in data ormeta-data , leading to the need for consistency checking . In this paper we make a parallel between programs and Web sites . We present some examples of semantic constraints that one would like to specify ( constraints between the meaning of categories and sub-categories in a thematic directory , consistency between the organization chart and the rest of the site in an academic site ) . We present quickly the Natural Semantics a way to specify the semantics of programming languages that inspires ourworks . Natural Semantics itself comes from both an operational semantics and from logic programming and its implementation uses Prolog . Then we propose a specification language for semantic constraints in Web sites that , in conjunction with the well known `` make '' program , permits to generate some site verification tools by compiling the specification into Prolog code . We apply our method to alarge XML document which is the scientific part of our instituteactivity report , tracking errors or inconsistencies and alsoconstructing some indicators that can be used by the management of theinstitute .

O O O O B I O O O B I O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

consistency
logic programming
quality
web sites
xml

content management
formal semantics
information system
knowledge management
web engineering
web site evolution


Winner takes all : competing viruses or ideas on fair-play networks Given two competing products ( or memes , or viruses etc. ) spreading over a given network , can we predict what will happen at the end , that is , which product will ` win ' , in terms of highest market share ? One may naively expect that the better product ( stronger virus ) will just have a larger footprint , proportional to the quality ratio of the products ( or strength ratio of the viruses ) . However , we prove the surprising result that , under realistic conditions , for any graph topology , the stronger virus completely wipes-out the weaker one , thus not merely ` winning ' but ` taking it all ' . In addition to the proofs , we also demonstrate our result with simulations over diverse , real graph topologies , including the social-contact graph of the city of Portland OR ( about 31 million edges and 1 million nodes ) and internet AS router graphs . Finally , we also provide real data about competing products from Google-Insights , like Facebook-Myspace , and we show again that they agree with our analysis .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

cascades competition epidemics winner-takes-all


Entity relation discovery from web tables and links The World-Wide Web consists not only of a huge number of unstructured texts , but also a vast amount of valuable structured data . Web tables ( 2 ) are a typical type of structured information that are pervasive on the web , and Web-scale methods that automatically extract web tables have been studied extensively ( 1 ) . Many powerful systems ( e.g. OCTOPUS ( 4 ) , Mesa ( 3 ) ) use extracted web tables as a fundamental component . In the database vernacular , a table is defined as a set of tuples which have the same attributes . Similarly , a web table is defined as a set of rows ( corresponding to database tuples ) which have the same column headers ( corresponding to database attributes ) . Therefore , to extract a web table is to extract a relation on the web . In databases , tables often contain foreign keys which refer to other tables . Therefore , it follows that hyperlinks inside a web table sometimes function as foreign keys to other relations whose tuples are contained in the hyperlink 's target pages . In this paper , we explore this idea by asking : can we discover new attributes for web tables by exploring hyperlinks inside web tables ? This poster proposes a solution that takes a web table as input . Frequent patterns are generated as new candidate relations by following hyperlinks in the web table . The confidence of candidates are evaluated , and trustworthy candidates are selected to become new attributes for the table . Finally , we show the usefulness of our method by performing experiments on a variety of web domains .

B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Summarization of archived and shared personal photo collections The volume of personal photos hosted on photo archives and social sharing platforms has been increasing exponentially . It is difficult to get an overview of a large collection of personal photos without browsing though the entire database manually . In this research , we propose a framework to generate representative subset summaries from photo collections hosted on web archives or social networks . We define salient properties of an effective photo summary and model summarization as an optimization of these properties , given the size constraints . We also introduce metrics for evaluating photo summaries based on their information content and the ability to satisfy user 's information needs . Our experiments show that our summarization framework performs better than baseline algorithms .

B O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O

optimization
personal photos
social networks
summarization


Bid optimization for broad match ad auctions Ad auctions in sponsored search support `` broad match '' that allows an advertiser to target a large number of queries while bidding only on a limited number . While giving more expressiveness to advertisers , this feature makes it challenging to optimize bids to maximize their returns : choosing to bid on a query as a broad match because it provides high profit results in one bidding for related queries which may yield low or even negative profits . We abstract and study the complexity of the { \ em bid optimization problem } which is to determine an advertiser 's bids on a subset of keywords ( possibly using broad match ) so that her profit is maximized . In the query language model when the advertiser is allowed to bid on all queries as broad match , we present a linear programming ( LP ) - based polynomial-time algorithm that gets the optimal profit . In the model in which an advertiser can only bid on keywords , ie. , a subset of keywords as an exact or broad match , we show that this problem is not approximable within any reasonable approximation factor unless P = NP . To deal with this hardness result , we present a constant-factor approximation when the optimal profit significantly exceeds the cost . This algorithm is based on rounding a natural LP formulation of the problem . Finally , we study a budgeted variant of the problem , and show that in the query language model , one can find two budget constrained ad campaigns in polynomial time that implement the optimal bidding strategy . Our results are the first to address bid optimization under the broad match feature which is common in ad auctions .

B I O O O B I B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O B I O O O O O O O O O B I O

ad auctions
bid optimization
optimal bidding
sponsored search

analysis of algorithms and problem complexity


On ranking techniques for desktop search This paper addresses the desktop search problem by considering varioustechniques for ranking results of a search query over thefile system . First , basic ranking techniques , which are based ona single file feature ( e.g. , file name , file content , access date , etc. ) are considered . Next , two learning-based ranking schemes are presented , and are shown to be significantly more effective than the basic ranking methods . Finally , a novel ranking technique , based on query selectiveness is considered , for use during the cold-start period of the system . This method isalso shown to be empirically effective , even though it does notinvolve any learning .

O B O O B I O O O O B I O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

information search and retrieval
personal information management


PodCred : a framework for analyzing podcast preference The PodCred framework is a framework for assessing the credibility and quality of podcasts published on the internet . It consists of a series of indicators designed to support prediction of listener preference of one podcast over another , given that both carry comparable informational content . The indicators are grouped into four categories pertaining to the Podcast Content , the Podcaster , the Podcast Context or the Technical Execution of the podcast . We adopt the term `` cred '' as a designation encompassing both credibility ( comprising trustworthiness and expertise ) and qualitative acceptability to listeners . Our podcast analysis framework is inspired by work on credibility in blogs , another medium dominated by user generated content . The PodCred framework is derived from a review of the literature on credibility for other media , a survey of prescriptive standards for podcasting , and a detailed data analysis of award winning podcasts . The paper concludes with a discussion of future work in which the framework will be applied .

O O O O O O O O O O O O O O O O O B O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O

assessment
miscellaneous
user preferences


Text joins in an RDBMS for web data integration The integration of data produced and collected across autonomous , heterogeneous web services is an increasingly important and challenging problem . Due to the lack of global identifiers , the same entity ( e.g. , a product ) might have different textual representations across databases . Textual data is also often noisy because of transcription errors , incomplete information , and lack of standard formats . A fundamental task during data integration is matching of strings that refer to the same entity . In this paper , we adopt the widely used and established cosine similarity metric from the information retrieval field in order to identify potential string matches across web sources . We then use this similarity metric to characterize this key aspect of data integration as a join between relations on textual attributes , where the similarity of matches exceeds a specified threshold . Computing an exact answer to the text join can be expensive . For query processing efficiency , we propose a sampling-based join approximation strategy for execution in a standard , unmodified relational database management system ( RDBMS ) , since more and more web sites are powered by RDBMSs with a web-based front end . We implement the join inside an RDBMS , using SQL queries , for scalability and robustness reasons . Finally , we present a detailed performance evaluation of an implementation of our algorithm within a commercial RDBMS , using real-life data sets . Our experimental results demonstrate the efficiency and accuracy of our techniques .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

approximate text matching
data cleaning
heterogeneous databases
text indexing