OpenRaiser/Intern-Atlas huggingface dataset:
"I loan because...": understanding motivations for pro-social lending
Authors: Yang Liu, Roy Chen, Yan Chen, Qiaozhu Mei, Suzy Salib
Venue: WSDM
Year: 2012

As a new paradigm of online communities, microfinance sites such as Kiva.org have attracted much public attention. To understand lender motivations on Kiva, we classify the lenders' self-stated motivations into ten categories with human coders and machine learning based classifiers. We employ text classifiers using lexical features, along with social features based on lender activity information on Kiva, to predict the categories of lender motivation statements. Although the task appears to be much more challenging than traditional topic-based categorization, our classifiers can achieve high precision in most categories. Using the results of this classification along with Kiva teams information, we predict lending activity from lender motivation and team affiliations. Finally, we make design recommendations regarding Kiva practices which might increase pro-social lending.
Finding the right consumer: optimizing for conversion in display advertising campaigns
Authors: Yandong Liu, Sandeep Pandey, Deepak Agarwal, Vanja Josifovski
Venue: WSDM
Year: 2012

The ultimate goal of advertisers are conversions representing desired user actions on the advertisers' websites in the form of purchases and product information request. In this paper we address the problem of finding the right audience for display campaigns by finding the users that are most likely to convert. This challenging problem is at the heart of display campaign optimization and has to deal with several issues such as very small percentage of converters in the general population, high-dimensional representation of the user profiles, large churning rate of users and advertisers. To overcome these difficulties, in our approach we use two sources of information: a seed set of users that have converted for a campaign in the past; and a description of the campaign based on the advertiser's website. We explore the importance of the information provided by each of these two sources in a principled manner and then combine them to propose models for predicting converters. In particular, we show how seed set can be used to capture the campaign-specific targeting constraints, while the campaign metadata allows to share targeting knowledge across campaigns. We give methods for learning these models and perform experiments on real-world advertising campaigns. Our findings show that the seed set and the campaign metadata are complimentary to each other and both sources provide valuable information for conversion optimization.
Pairwise cross-domain factor model for heterogeneous transfer ranking
Authors: Bo Long, Yi Chang, Anlei Dong, Jianzhang He
Venue: WSDM
Year: 2012

Learning to rank arises in many information retrieval applications, ranging from Web search engine, online advertising to recommendation systems. Traditional ranking mainly focuses on one type of data source, and effective modeling relies on a sufficiently large number of labeled examples, which require expensive and time-consuming labeling process. However, in many real-world applications, ranking over multiple related heterogeneous domains becomes a common situation, where in some domains we may have a relatively large amount of training data while in some other domains we can only collect very little. Theretofore, how to leverage labeled information from related heterogeneous domain to improve ranking in a target domain has become a problem of great interests. In this paper, we propose a novel probabilistic model, pairwise cross-domain factor model, to address this problem. The proposed model learns latent factors(features) for multi-domain data in partially-overlapped heterogeneous feature spaces. It is capable of learning homogeneous feature correlation, heterogeneous feature correlation, and pairwise preference correlation for cross-domain knowledge transfer. We also derive two PCDF variations to address two important special cases. Under the PCDF model, we derive a stochastic gradient based algorithm, which facilitates distributed optimization and is flexible to adopt different loss functions and regularization functions to accommodate different data distributions. The extensive experiments on real world data sets demonstrate the effectiveness of the proposed model and algorithm.
2nd international workshop on diversity in document retrieval (DDR 2012)
Authors: Craig Macdonald, Jun Wang, Charles L. A. Clarke
Venue: WSDM
Year: 2012

When an ambiguous query is received, a sensible approach is for the information retrieval (IR) system to diversify the results retrieved for this query, in the hope that at least one of the interpretations of the query intent will satisfy the user. Diversity is an increasingly important topic, of interest to both academic researchers (such as participants in the TREC Web and Blog track diversity tasks, or the NTCIR INTENT task), as well as to search engines professionals. In the 2nd edition of the Diversity in Document Retrieval workshop (DDR 2012), we solicited submissions both on approaches and models for diversity, the evaluation of diverse search results, and on applications of diverse search results. This workshop builds upon a successful 1st edition of DDR which was held at ECIR 2011 in Dublin, Ireland.
The secret life of social links
Authors: Hilary Mason
Venue: WSDM
Year: 2012

The social web is a messy place! At bitly, we see hundreds of millions of shares and clicks per day--clicks that contain all sorts of wonderful content from lolcats to spacecraft launches. I'll discuss our philosophy, tools, and techniques for looking at the data, and new research opportunities that weren't possible before.
Language models for keyword search over data graphs
Authors: Yosi Mass, Yehoshua Sagiv
Venue: WSDM
Year: 2012

In keyword search over data graphs, an answer is a non-redundant subtree that includes the given keywords. This paper focuses on improving the effectiveness of that type of search. A novel approach that combines language models with structural relevance is described. The proposed approach consists of three steps. First, language models are used to assign dynamic, query-dependent weights to the graph. Those weights complement static weights that are pre-assigned to the graph. Second, an existing algorithm returns candidate answers based on their weights. Third, the candidate answers are re-ranked by creating a language model for each one. The effectiveness of the proposed approach is verified on a benchmark of three datasets: IMDB, Wikipedia and Mondial. The proposed approach outperforms all existing systems on the three datasets, which is a testament to its robustness. It is also shown that the effectiveness can be further improved by augmenting keyword queries with very basic knowledge about the structure.
Of hammers and nails: an empirical comparison of three paradigms for processing large graphs
Authors: Marc Najork, Dennis Fetterly, Alan Halverson, Krishnaram Kenthapadi, Sreenivas Gollapudi
Venue: WSDM
Year: 2012

Many phenomena and artifacts such as road networks, social networks and the web can be modeled as large graphs and analyzed using graph algorithms. However, given the size of the underlying graphs, efficient implementation of basic operations such as connected component analysis, approximate shortest paths, and link-based ranking (e.g. PageRank) becomes challenging.
How user behavior is related to social affinity
Authors: Rina Panigrahy, Marc Najork, Yinglian Xie
Venue: WSDM
Year: 2012

Previous research has suggested that people who are in the same social circle exhibit similar behaviors and tastes. The rise of social networks gives us insights into the social circles of web users, and recommendation services (including search engines, advertisement engines, and collaborative filtering engines) provide a motivation to adapt recommendations to the interests of the audience. An important primitive for supporting these applications is the ability to quantify how connected two users are in a social network. The shortest-path distance between a pair of users is an obvious candidate measure. This paper introduces a new measure of "affinity" in social networks that takes into account not only the distance between two users, but also the number of edge-disjoint paths between them, i.e. the "robustness" of their connection. Our measure is based on a sketch-based approach, and affinity queries can be answered extremely efficiently (at the expense of a one-time offline sketch computation). We compare this affinity measure against the "approximate shortest-path distance", a sketch-based distance measure with similar efficiency characteristics. Our empirical study is based on a Hotmail email exchange graph combined with demographic information and Bing query history, and a Twitter mention-graph together with the text of the underlying tweets. We found that users who are close to each other - either in terms of distance or affinity - have a higher similarity in terms of demographics, queries, and tweets.
Beyond 100 million entities: large-scale blocking-based resolution for heterogeneous data
Authors: George Papadakis, Ekaterini Ioannou, Claudia Niederée, Themis Palpanas, Wolfgang Nejdl
Venue: WSDM
Year: 2012

A prerequisite for leveraging the vast amount of data available on the Web is Entity Resolution, i.e., the process of identifying and linking data that describe the same real-world objects. To make this inherently quadratic process applicable to large data sets, blocking is typically employed: entities (records) are grouped into clusters - the blocks - of matching candidates and only entities of the same block are compared. However, novel blocking techniques are required for dealing with the noisy, heterogeneous, semi-structured, user-generateddata in the Web, as traditional blocking techniques are inapplicable due to their reliance on schema information. The introduction of redundancy, improves the robustness of blocking methods but comes at the price of additional computational cost.
IR system evaluation using nugget-based test collections
Authors: Virgiliu Pavlu, Shahzad Rajput, Peter B. Golbus, Javed A. Aslam
Venue: WSDM
Year: 2012

The development of information retrieval systems such as search engines relies on good test collections, including assessments of retrieved content. The widely employed Cranfield paradigm dictates that the information relevant to a topic be encoded at the level of documents, therefore requiring effectively complete document relevance assessments. As this is no longer practical for modern corpora, numerous problems arise, including scalability, reusability, and applicability. We propose a new method for relevance assessment based on relevant information, not relevant documents. Once the relevant 'nuggets' are collected, our matching method can assess any document for relevance with high accuracy, and so any retrieved list of documents can be assessed for performance. In this paper we analyze the performance of the matching function by looking at specific cases and by comparing with other methods. We then show how these inferred relevance assessments can be used to perform IR system evaluation, and we discuss in particular reusability and scalability. Our main contribution is a methodology for producing test collections that are highly accurate, more complete, scalable, reusable, and can be generated with similar amounts of effort as existing methods, with great potential for future applications.
Characterizing and harnessing peer-production of information in social tagging systems
Authors: Elizeu Santos-Neto
Venue: WSDM
Year: 2012

Assessing the value of individual users' contributions in peer-production systems is paramount to the design of mechanisms that support collaboration and improve users' experience. For instance, to incentivize contributions, file sharing systems based on the BitTorrent protocol equate value with volume of contributed content and use a prioritization mechanism to reward users who contribute more. This approach and similar techniques used in resource sharing systems rely on the fact that the physical resources shared among users are easily quantifiable.
WSCD 2012: workshop on web search click data 2012
Authors: Pavel Serdyukov, Nick Craswell, Georges Dupret
Venue: WSDM
Year: 2012

WSCD2012 is the second workshop on Web Search Click Data, following WSCD2009. It is a forum for new research relating to Web search usage logs and for discussing desirable properties of publicly released search log datasets. Research relating to search logs has been hampered by the limited availability of click datasets. This workshop comes with a new click dataset based on click logs and an accompanying challenge to predict the relevance of documents based on clicks.
Collaborative information seeking: understanding users, systems, and content
Authors: Chirag Shah
Venue: WSDM
Year: 2012

The course will introduce the student to theories, methodologies, and tools that focus on information retrieval/seeking in collaboration. The student will have an opportunity to learn about the social aspect of IR with a focus on collaborative information seeking (CIS) situations, systems, and evaluation techniques. Traditionally, IR is considered an individual pursuit, and not surprisingly, the majority of tools, techniques, and models developed for addressing information need, retrieval, and usage have focused on single users. The assumption of information seekers being independent and IR problem being individual has been challenged often in the recent past. This course will introduce such works to the students, with an emphasis on understanding models and systems that support collaborative search or browsing. In addition, the course will provide samples of data collected through several experiments to demonstrate various mining and analysis techniques.
Optimized top-k processing with global page scores on block-max indexes
Authors: Dongdong Shan, Shuai Ding, Jing He, Hongfei Yan, Xiaoming Li
Venue: WSDM
Year: 2012

Large web search engines are facing formidable performance challenges because they have to process thousands of queries per second on tens of billions of documents, within interactive response time. Among many others, Top-k query processing (also called early termination or dynamic pruning) is an important class of optimization techniques that can improve the search efficiency and achieve faster query processing by avoiding the scoring of documents that are unlikely to be in the top results. One recent technique is using Block-Max index. In the Block-Max index, the posting lists are organized as blocks and the maximum score for each block is stored to improve the query efficiency. Although query processing speedup is achieved with Block-Max index, the ranking function for the Top-k results is the term-based approach. It is well known that documents' static scores are also important for a good ranking function. In this paper, we show that the performance of the state-of-the-art algorithms with the Block-Max index is degraded when the static score is added in the ranking function. Then we study efficient techniques for Top-k query processing in the case where a page's static score is given, such as PageRank, in addition to the term-based approach. In particular, we propose a set of new algorithms based on the WAND and MaxScore with Block-Max index using local score, which outperform the existing ones. Then we propose new techniques to estimate a better score upper bound for each block. We also study the search efficiency on different index structures where the document identifiers are assigned by URL sorting or by static document scores. Experiments on TREC GOV2 and ClueWeb09B show that considerable performance gains are achieved.
Query suggestion by constructing term-transition graphs
Authors: Yang Song, Dengyong Zhou, Li-wei He
Venue: WSDM
Year: 2012

Query suggestion is an interactive approach for search engines to better understand users information need. In this paper, we propose a novel query suggestion framework which leverages user re-query feedbacks from search engine logs. Specifically, we mined user query reformulation activities where the user only modifies part of the query by (1) adding terms after the query, (2) deleting terms within the query, or (3) modifying terms to new terms. We build a term-transition graph based on the mined data. Two models are proposed which address topic-level and term-level query suggestions, respectively. In the first topic-based unsupervised Pagerank model, we perform random walk on each of the topic-based term-transition graph and calculate the Pagerank for each term within a topic. Given a new query, we suggest relevant queries based on its topic distribution and term-transition probability within each topic. Our second model resembles the supervised learning-to-rank (LTR) framework, in which term modifications are treated as documents so that each query reformulation is treated as a training instance. A rich set of features are constructed for each (query, document) pair from Pagerank, Wikipedia, N-gram, ODP and so on. This supervised model is capable of suggesting new queries on a term level which addresses the limitation of previous methods. Experiments are conducted on a large data set from a commercial search engine. By comparing the with state-of-the-art query suggestion methods [4, 2], our proposals exhibit significant performance increase for all categories of queries.
To each his own: personalized content selection based on text comprehensibility
Authors: Chenhao Tan, Evgeniy Gabrilovich, Bo Pang
Venue: WSDM
Year: 2012

Imagine a physician and a patient doing a search on antibiotic resistance. Or a chess amateur and a grandmaster conducting a search on Alekhine's Defence. Although the topic is the same, arguably the two users in each case will satisfy their information needs with very different texts. Yet today search engines mostly adopt the one-size-fits-all solution, where personalization is restricted to topical preference. We found that users do not uniformly prefer simple texts, and that the text comprehensibility level should match the user's level of preparedness. Consequently, we propose to model the comprehensibility of texts as well as the users' reading proficiency in order to better explain how different users choose content for further exploration. We also model topic-specific reading proficiency, which allows us to better explain why a physician might choose to read sophisticated medical articles yet simple descriptions of SLR cameras. We explore different ways to build user profiles, and use collaborative filtering techniques to overcome data sparsity. We conducted experiments on large-scale datasets from a major Web search engine and a community question answering forum. Our findings confirm that explicitly modeling text comprehensibility can significantly improve content ranking (search results or answers, respectively).
Inferring social ties across heterogenous networks
Authors: Jie Tang, Tiancheng Lou, Jon M. Kleinberg
Venue: WSDM
Year: 2012

It is well known that different types of social ties have essentially different influence on people. However, users in online social networks rarely categorize their contacts into "family", "colleagues", or "classmates". While a bulk of research has focused on inferring particular types of relationships in a specific social network, few publications systematically study the generalization of the problem of inferring social ties over multiple heterogeneous networks. In this work, we develop a framework for classifying the type of social relationships by learning across heterogeneous networks. The framework incorporates social theories into a factor graph model, which effectively improves the accuracy of inferring the type of social relationships in a target network by borrowing knowledge from a different source network. Our empirical study on five different genres of networks validates the effectiveness of the proposed framework. For example, by leveraging information from a coauthor network with labeled advisor-advisee relationships, the proposed framework is able to obtain an F1-score of 90% (8-28% improvements over alternative methods) for inferring manager-subordinate relationships in an enterprise email network.
The early bird gets the buzz: detecting anomalies and emerging trends in information networks
Authors: Brian Thompson
Venue: WSDM
Year: 2012

In this work we propose a novel approach to anomaly detection in streaming communication data. We first build a stochastic model for the system based on temporal communication patterns across each edge, which we call the REWARDS (REneWal theory Approach for Real-time Data Streams) model. We then define a measure of anomaly for an arbitrary subgraph based on the likelihood of its recent activity given past behavior. Finally, we develop an algorithm to efficiently identify subgraphs with the most anomalous activity. Although our work has until now focused on the cybersecurity domain, the model we present is more broadly applicable to information retrieval in data streams and information networks.
What's in a hashtag?: content based prediction of the spread of ideas in microblogging communities
Authors: Oren Tsur, Ari Rappoport
Venue: WSDM
Year: 2012

Current social media research mainly focuses on temporal trends of the information flow and on the topology of the social graph that facilitates the propagation of information. In this paper we study the effect of the content of the idea on the information propagation. We present an efficient hybrid approach based on a linear regression for predicting the spread of an idea in a given time frame. We show that a combination of content features with temporal and topological features minimizes prediction error.
Nowcasting the macroeconomy with search engine data
Authors: Hal R. Varian
Venue: WSDM
Year: 2012

It is now possible to acquire real time information on economic variables of interest from various commercial sources. I illustrate how one can use Google Trends data to measure the state of the macroeconomy in various sectors, and discuss some of the ramifications for research and policy.
Tips, dones and todos: uncovering user profiles in foursquare
Authors: Marisa A. Vasconcelos, Saulo M. R. Ricci, Jussara M. Almeida, Fabrício Benevenuto, Virgílio A. F. Almeida
Venue: WSDM
Year: 2012

Online Location Based Social Networks (LBSNs), which combine social network features with geographic information sharing, are becoming increasingly popular. One such application is Foursquare, which doubled its user population in less than six months. Among other features, Foursquare allows users to leave tips (i.e., reviews or recommendations) at specific venues as well as to give feedback on previously posted tips by adding them to their to-do lists or marking them as done. In this paper, we analyze how Foursquare users exploit these three features - tips, dones and to-dos - uncovering different behavior profiles. Our study reveals the existence of very active and influential users, some of which are famous businesses and brands, that seem engaged in posting tips at a large variety of venues while also receiving a great amount of user feedback on them. We also provide evidence of spamming, showing the existence of users that post tips whose contents are unrelated to the nature or domain of the venue where the tips were left.