bluuebunny/crossref_metadata_2025 huggingface dataset:
Variational inference with graph regularization for image annotation
Authors: Shao Yuanlong , Zhou Yuan , Cai Deng
Published: October 2012

Image annotation is a typical area where there are multiple types of attributes associated with each individual image. In order to achieve better performance, it is important to develop effective modeling by utilizing prior knowledge. In this article, we extend the graph regularization approaches to a more general case where the regularization is imposed on the factorized variational distributions, instead of posterior distributions implicitly involved in EM-like algorithms. In this way, the problem modeling can be more flexible, and we can choose any factor in the problem domain to impose graph regularization wherever there are similarity constraints among the instances. We formulate the problem formally and show its geometrical background in manifold learning. We also design two practically effective algorithms and analyze their properties such as the convergence. Finally, we apply our approach to image annotation and show the performance improvement of our algorithm.
Collection-based sparse label propagation and its application on social group suggestion from photos
Authors: Yu Jie , Jin Xin , Han Jiawei , Luo Jiebo
Published: October 2012

Online social network services pose great opportunities and challenges for many research areas. In multimedia content analysis, automatic social group recommendation for images holds the promise to expand one's social network through media sharing. However, most existing techniques cannot generate satisfactory social group suggestions when the images are classified independently. In this article, we present novel methods to produce accurate suggestions of suitable social groups from a user's personal photo collection. First, an automatic clustering process is designed to estimate the group similarities, select the optimal number of clusters and categorize the social groups. Both visual content and textual annotations are integrated to generate initial predictions of the group categories for the images. Next, the relationship among images in a user's collection is modeled as a sparse graph. A collection-based sparse label propagation method is proposed to improve the group suggestions. Furthermore, the sparse graph-based collection model can be readily exploited to select the most influential and informative samples for active relevance feedback, which can be integrated with the label propagation process without the need for classifier retraining. The proposed methods have been tested on group suggestion tasks for real user collections and demonstrated superior performance over the state-of-the-art techniques.
Image annotation by
k
NN-sparse graph-based label propagation over noisily tagged web images
Authors: Tang Jinhui , Hong Richang , Yan Shuicheng , Chua Tat-Seng , Qi Guo-Jun , Jain Ramesh
Published: October 2012

In this article, we exploit the problem of annotating a large-scale image corpus by label propagation over noisily tagged web images. To annotate the images more accurately, we propose a novel
k
NN-sparse graph-based semi-supervised learning approach for harnessing the labeled and unlabeled data simultaneously. The sparse graph constructed by datum-wise one-vs-
k
NN sparse reconstructions of all samples can remove most of the semantically unrelated links among the data, and thus it is more robust and discriminative than the conventional graphs. Meanwhile, we apply the approximate
k
nearest neighbors to accelerate the sparse graph construction without loosing its effectiveness. More importantly, we propose an effective training label refinement strategy within this graph-based learning framework to handle the noise in the training labels, by bringing in a dual regularization for both the quantity and sparsity of the noise. We conduct extensive experiments on a real-world image database consisting of 55,615 Flickr images and noisily tagged training labels. The results demonstrate both the effectiveness and efficiency of the proposed approach and its capability to deal with the noise in the training labels.
Automatic player labeling, tracking and field registration and trajectory mapping in broadcast soccer video
Authors: Tong Xiaofeng , Liu Jia , Wang Tao , Zhang Yimin
Published: October 2012

In this article, we present a method to perform automatic player trajectories mapping based on player detection, unsupervised labeling, efficient multi-object tracking, and playfield registration in broadcast soccer videos. Player detector determines the players' positions and scales by combining the ability of dominant color based background subtraction and a boosting detector with Haar features. We first learn the dominant color with accumulate color histogram at the beginning of processing, then use the player detector to collect hundreds of player samples, and learn player appearance codebook by unsupervised clustering. In a soccer game, a player can be labeled as one of four categories: two teams, referee or outlier. The learning capability enables the method to be generalized well to different videos without any manual initialization. With the dominant color and player appearance model, we can locate and label each player. After that, we perform multi-object tracking by using Markov Chain Monte Carlo (MCMC) data association to generate player trajectories. Some data driven dynamics are proposed to improve the Markov chain's efficiency, such as label consistency, motion consistency, and track length, etc. Finally, we extract key-points and find the mapping from an image plane to the standard field model, and then map players' position and trajectories to the field. A large quantity of experimental results on FIFA World Cup 2006 videos demonstrate that this method can reach high detection and labeling precision, reliably tracking in scenes of player occlusion, moderate camera motion and pose variation, and yield promising field registration results.
Probabilistic temporal multimedia data mining
Authors: Bhatt Chidansh , Kankanhalli Mohan
Published: October 2012

Existing sequence pattern mining techniques assume that the obtained events from event detectors are accurate. However, in reality, event detectors label the events from different modalities with a certain probability over a time-interval. In this article, we consider for the first time Probabilistic Temporal Multimedia (PTM) Event data to discover accurate sequence patterns. PTM event data considers the start time, end time, event label and associated probability for the sequence pattern discovery. As the existing sequence pattern mining techniques cannot work on such realistic data, we have developed a novel framework for performing sequence pattern mining on probabilistic temporal multimedia event data. We perform probability fusion to resolve the redundancy among detected events from different modalities, considering their cross-modal correlation. We propose a novel sequence pattern mining algorithm called Probabilistic Interval based Event Miner (PIE-Miner) for discovering frequent sequence patterns from interval based events. PIE-Miner has a new support counting mechanism developed for PTM data. Existing sequence pattern mining algorithms have event label level support counting mechanism, whereas we have developed event cluster level support counting mechanism. We discover the complete set of all possible temporal relationships based on Allen's interval algebra. The experimental results showed that the discovered sequence patterns are more useful than the patterns discovered with state-of-the-art sequence pattern mining algorithms.
A learning-based contrarian trading strategy via a dual-classifier model
Authors: Huang Szu-Hao , Lai Shang-Hong , Tai Shih-Hsien
Published: October 2012

Behavioral finance is a relatively new and developing research field which adopts cognitive psychology and emotional bias to explain the inefficient market phenomenon and some irrational trading decisions. Unlike the experts in this field who tried to reason the price anomaly and applied empirical evidence in many different financial markets, we employ the advanced binary classification algorithms, such as AdaBoost and support vector machines, to precisely model the overreaction and strengthen the portfolio compositions of the contrarian trading strategies. The novelty of this article is to discover the financial time-series patterns through a high-dimensional and nonlinear model which is constructed by integrated knowledge of finance and machine learning techniques. We propose a dual-classifier learning framework to select candidate stocks from the past results of original contrarian trading strategies based on the defined learning targets. Three different feature extraction methods, including wavelet transformation, historical return distribution, and various technical indicators, are employed to represent these learning samples in a 381-dimensional financial time-series feature space. Finally, we construct the classifier models with four different learning kernels and prove that the proposed methods could improve the returns dramatically, such as the 3-year return that improved from 26.79% to 53.75%. The experiments also demonstrate significantly higher portfolio selection accuracy, improved from 57.47% to 66.41%, than the original contrarian trading strategy. To sum up, all these experiments show that the proposed method could be extended to an effective trading system in the historical stock prices of the leading U.S. companies of S&P 100 index.
CORN
Authors: Li Bin , Hoi Steven C.H. , Gopalkrishnan Vivekanand
Published: October 2012

Machine learning techniques have been adopted to select portfolios from financial markets in some emerging intelligent business applications. In this article, we propose a novel learning-to-trade algorithm termed
COR
relation-driven
N
onparametric learning strategy (CORN) for actively trading stocks. CORN effectively exploits statistical relations between stock market windows via a nonparametric learning approach. We evaluate the empirical performance of our algorithm extensively on several large historical and latest real stock markets, and show that it can easily beat both the market index and the best stock in the market substantially (without or with small transaction costs), and also surpass a variety of state-of-the-art techniques significantly.
Social Network Analysis and Mining for Business Applications
Authors: Bonchi Francesco , Castillo Carlos , Gionis Aristides , Jaimes Alejandro
Published: October 2012

Social network analysis has gained significant attention in recent years, largely due to the success of online social networking and media-sharing sites, and the consequent availability of a wealth of social network data. In spite of the growing interest, however, there is little understanding of the potential business applications of mining social networks. While there is a large body of research on different problems and methods for social network mining, there is a gap between the techniques developed by the research community and their deployment in real-world applications. Therefore the potential business impact of these techniques is still largely unexplored.

In this article we use a business process classification framework to put the research topics in a business context and provide an overview of what we consider key problems and techniques in social network analysis and mining from the perspective of business applications. In particular, we discuss data acquisition and preparation, trust, expertise, community structure, network dynamics, and information propagation. In each case we present a brief overview of the problem, describe state-of-the art approaches, discuss business application examples, and map each of the topics to a business process classification framework. In addition, we provide insights on prospective business applications, challenges, and future research directions. The main contribution of this article is to provide a state-of-the-art overview of current techniques while providing a critical perspective on business applications of social network analysis and mining.
A helpfulness modeling framework for electronic word-of-mouth on consumer opinion platforms
Authors: Zhang Richong , Tran Thomas
Published: October 2012

Electronic Word-of-Mouth (eWOM) is growing exponentially with the rapid development of electronic commerce. As a result, consumers are increasingly crowded by a huge amount of eWOM contents and therefore there is a need to automatically recommend eWOM contents that are helpful to them. Existing helpfulness assessment approaches that deterministically estimate the helpfulness of eWOM contents lack a generative formulation and are limited to the training set that has been voted by many readers. This article presents a rigorous probabilistic framework for inferring the “helpfulness” of eWOM contents which can build a “helpfulness” model from a low number of votes on eWOM contents. Furthermore, we introduce a measurement, “helpfulness” bias, as the benchmark for the “helpfulness” of eWOM documents. We also propose a model that exploits the graphical model and expectation maximization algorithm, under this probabilistic framework, to demonstrate the versatility of our framework. Our algorithm is compared experimentally to other existing helpfulness discovering algorithms and the experimental results show that our framework can effectively model the helpfulness of eWOM contents better than other approaches, and therefore indicate the capability of our framework to recommend helpful eWOMs to potential consumers.
Multifocal learning for customer problem analysis
Authors: Ge Yong , Xiong Hui , Zhou Wenjun , Li Siming , Sahoo Ramendra
Published: October 2012

In this study, we formalize a multifocal learning problem, where training data are partitioned into several different focal groups and the prediction model will be learned within each focal group. The multifocal learning problem is motivated by numerous real-world learning applications. For instance, for the same type of problems encountered in a customer service center, the problem descriptions from different customers can be quite different. Experienced customers usually give more precise and focused descriptions about the problem. In contrast, inexperienced customers usually provide diverse descriptions. In this case, the examples from the same class in the training data can be naturally in different focal groups. Therefore, it is necessary to identify those natural focal groups and exploit them for learning at different focuses. Along this line, the key development challenge is how to identify those focal groups in the training data. As a case study, we exploit multifocal learning for profiling customer problems. Also, we provide an empirical study about how the performance of multifocal learning is affected by the quality of focal groups. The results on real-world customer problem logs show that multifocal learning can significantly boost the performance of many existing classification algorithms, such as Support Vector Machines (SVMs), for classifying customer problems and there is strong correlation between the quality of focal groups and the learning performance.
Batch and online learning algorithms for nonconvex neyman-pearson classification
Authors: Gasso Gilles , Pappaioannou Aristidis , Spivak Marina , Bottou Léon
Published: October 2012

We describe and evaluate two algorithms for Neyman-Pearson (NP) classification problem which has been recently shown to be of a particular importance for bipartite ranking problems. NP classification is a nonconvex problem involving a constraint on false negatives rate. We investigated batch algorithm based on DC programming and stochastic gradient method well suited for large-scale datasets. Empirical evidences illustrate the potential of the proposed methods.
Learning to recommend with explicit and implicit social relations
Authors: Ma Hao , King Irwin , Lyu Michael R.
Published: October 2012

Recommender systems
have been well studied and developed, both in academia and in industry recently. However, traditional recommender systems assume that all the users are independent and identically distributed; this assumption ignores the connections among users, which is not consistent with the real-world observations where we always turn to our trusted friends for recommendations. Aiming at modeling recommender systems more accurately and realistically, we propose a novel probabilistic factor analysis framework which naturally fuses the users' tastes and their trusted friends' favors together. The proposed framework is quite general, and it can also be applied to pure user-item rating matrix even if we do not have explicit social trust information among users. In this framework, we coin the term
social trust ensemble
to represent the formulation of the social trust restrictions on the recommender systems. The complexity analysis indicates that our approach can be applied to very large datasets since it scales linearly with the number of observations, while the experimental results show that our method outperforms state-of-the-art approaches.
Learning to detect malicious URLs
Authors: Ma Justin , Saul Lawrence K. , Savage Stefan , Voelker Geoffrey M.
Published: October 2012

Malicious Web sites are a cornerstone of Internet criminal activities. The dangers of these sites have created a demand for safeguards that protect end-users from visiting them. This article explores how to detect malicious Web sites from the lexical and host-based features of their URLs. We show that this problem lends itself naturally to modern algorithms for online learning. Online algorithms not only process large numbers of URLs more efficiently than batch algorithms, they also adapt more quickly to new features in the continuously evolving distribution of malicious URLs. We develop a real-time system for gathering URL features and pair it with a real-time feed of labeled URLs from a large Web mail provider. From these features and labels, we are able to train an online classifier that detects malicious Web sites with 99% accuracy over a balanced dataset.
Monitoring global forest cover using data mining
Authors: Mithal Varun , Garg Ashish , Boriah Shyam , Steinbach Michael , Kumar Vipin , Potter Christopher , Klooster Steven , Castilla-Rubio Juan Carlos
Published: October 2012

Forests are a critical component of the planet's ecosystem. Unfortunately, there has been significant degradation in forest cover over recent decades as a result of logging, conversion to crop, plantation, and pasture land, or disasters (natural or man made) such as forest fires, floods, and hurricanes. As a result, significant attention is being given to the sustainable use of forests. A key to effective forest management is quantifiable knowledge about changes in forest cover. This requires identification and characterization of changes and the discovery of the relationship between these changes and natural and anthropogenic variables. In this article, we present our preliminary efforts and achievements in addressing some of these tasks along with the challenges and opportunities that need to be addressed in the future. At a higher level, our goal is to provide an overview of the exciting opportunities and challenges in developing and applying data mining approaches to provide critical information for forest and land use management.
MoveMine
Authors: Li Zhenhui , Han Jiawei , Ji Ming , Tang Lu-An , Yu Yintao , Ding Bolin , Lee Jae-Gil , Kays Roland
Published: October 2012

With the maturity and wide availability of GPS, wireless, telecommunication, and Web technologies, massive amounts of object movement data have been collected from various moving object targets, such as animals, mobile devices, vehicles, and climate radars. Analyzing such data has deep implications in many applications, such as, ecological study, traffic control, mobile communication management, and climatological forecast. In this article, we focus our study on animal movement data analysis and examine advanced data mining methods for discovery of various animal movement patterns. In particular, we introduce a moving object data mining system, MoveMine, which integrates multiple data mining functions, including sophisticated pattern mining and trajectory analysis. In this system, two interesting moving object pattern mining functions are newly developed: (1)
periodic behavior mining
and (2)
swarm pattern mining
. For mining periodic behaviors, a reference location-based method is developed, which first detects the reference locations, discovers the periods in complex movements, and then finds periodic patterns by hierarchical clustering. For mining swarm patterns, an efficient method is developed to uncover flexible moving object clusters by relaxing the popularly-enforced collective movement constraints.

In the MoveMine system, a set of commonly used moving object mining functions are built and a user-friendly interface is provided to facilitate interactive exploration of moving object data mining and flexible tuning of the mining constraints and parameters. MoveMine has been tested on multiple kinds of real datasets, especially for MoveBank applications and other moving object data analysis. The system will benefit scientists and other users to carry out versatile analysis tasks to analyze object movement regularities and anomalies. Moreover, it will benefit researchers to realize the importance and limitations of current techniques and promote future studies on moving object data mining. As expected, a mastery of animal movement patterns and trends will improve our understanding of the interactions between and the changes of the animal world and the ecosystem and therefore help ensure the sustainability of our ecosystem.
Spatiotemporal correlations in criminal offense records
Authors: Toole Jameson L. , Eagle Nathan , Plotkin Joshua B.
Published: October 2012

With the increased availability of rich behavioral datasets, we present a novel application of tools to analyze this information. Using criminal offense records as an example, we employ cross-correlation measures, eigenvalue spectrum analysis, and results from random matrix theory to identify spatiotemporal patterns on multiple scales. With these techniques, we show that most significant correlation exists on the time scale of weeks and identify clusters of neighborhoods whose crime rates are affected simultaneously by external forces.
Subkilometer crater discovery with boosting and transfer learning
Authors: Ding Wei , Stepinski Tomasz F. , Mu Yang , Bandeira Lourenco , Ricardo Ricardo , Wu Youxi , Lu Zhenyu , Cao Tianyu , Wu Xindong
Published: October 2012

Counting craters in remotely sensed images is the only tool that provides relative dating of remote planetary surfaces. Surveying craters requires counting a large amount of small subkilometer craters, which calls for highly efficient automatic crater detection. In this article, we present an integrated framework on autodetection of subkilometer craters with boosting and transfer learning. The framework contains three key components. First, we utilize mathematical morphology to efficiently identify
crater candidates
, the regions of an image that can potentially contain craters. Only those regions occupying relatively small portions of the original image are the subjects of further processing. Second, we extract and select image texture features, in combination with supervised boosting ensemble learning algorithms, to accurately classify crater candidates into craters and noncraters. Third, we integrate transfer learning into boosting, to enhance detection performance in the regions where surface morphology differs from what is characterized by the training set. Our framework is evaluated on a large test image of 37,500 × 56,250 m
2
on Mars, which exhibits a heavily cratered Martian terrain characterized by nonuniform surface morphology. Empirical studies demonstrate that the proposed crater detection framework can achieve an F1 score above 0.85, a significant improvement over the other crater detection algorithms.
Efficient Tag Recommendation for Real-Life Data
Authors: Lipczak Marek , Milios Evangelos
Published: October 2012

Despite all of the advantages of tags as an easy and flexible information management approach, tagging is a cumbersome task. A set of descriptive tags has to be manually entered by users whenever they post a resource. This process can be simplified by the use of tag recommendation systems. Their objective is to suggest potentially useful tags to the user. We present a hybrid tag recommendation system together with a scalable, highly efficient system architecture. The system is able to utilize user feedback to tune its parameters to specific characteristics of the underlying tagging system and adapt the recommendation models to newly added content. The evaluation of the system on six real-life datasets demonstrated the system’s ability to combine tags from various sources (e.g., resource content or tags previously used by the user) to achieve the best quality of recommended tags. It also confirmed the importance of parameter tuning and content adaptation. A series of additional experiments allowed us to better understand the characteristics of the system and tagging datasets and to determine the potential areas for further system development.
A Case Study of Collaboration and Reputation in Social Web Search
Authors: McNally Kevin , O’Mahony Michael P. , Coyle Maurice , Briggs Peter , Smyth Barry
Published: October 2012

Although collaborative searching is not supported by mainstream search engines, recent research has highlighted the inherently collaborative nature of many Web search tasks. In this article, we describe HeyStaks, a collaborative Web search framework that is designed to complement mainstream search engines. At search time, HeyStaks learns from the search activities of other users and leverages this information to generate recommendations based on results that others have found relevant for similar searches. The key contribution of this article is to extend the HeyStaks social search model by considering the search expertise, or reputation, of HeyStaks users and using this information to enhance the result recommendation process. In particular, we propose a reputation model for HeyStaks users that utilise the implicit collaboration events that take place between users as recommendations are made and selected. We describe a live-user trial of HeyStaks that demonstrates the relevance of its core recommendations and the ability of the reputation model to further improve recommendation quality. Our findings indicate that incorporating reputation into the recommendation process further improves the relevance of HeyStaks recommendations by up to 40%.
GAPs
Authors: Shakarian Paulo , Subrahmanian V. S. , Sapino Maria Luisa
Published: October 2012

There are many applications where we observe various phenomena in space (e.g., locations of victims of a serial killer), and where we want to infer “partner” locations (e.g., the location where the killer lives) that are geospatially related to the observed phenomena. In this article, we define
geospatial abduction problems
(GAPs for short). We analyze the complexity of GAPs, develop exact and approximate algorithms (often with approximation guarantees) for these problems together with analyses of these algorithms, and develop a prototype implementation of our GAP framework. We demonstrate accuracy of our algorithms on a real world data set consisting of insurgent IED (improvised explosive device) attacks against U.S. forces in Iraq (the observations were the locations of the attacks, while the “partner” locations we were trying to infer were the locations of IED weapons caches).
An Adaptive Agent for Negotiating with People in Different Cultures
Authors: Gal Ya’akov , Kraus Sarit , Gelfand Michele , Khashan Hilal , Salmon Elizabeth
Published: October 2012

The rapid dissemination of technology such as the Internet across geographical and ethnic lines is opening up opportunities for computer agents to negotiate with people of diverse cultural and organizational affiliations. To negotiate proficiently with people in different cultures, agents need to be able to adapt to the way behavioral traits of other participants change over time. This article describes a new agent for repeated bilateral negotiation that was designed to model and adapt its behavior to the individual traits exhibited by its negotiation partner. The agent’s decision-making model combined a social utility function that represented the behavioral traits of the other participant, as well as a rule-based mechanism that used the utility function to make decisions in the negotiation process. The agent was deployed in a strategic setting in which both participants needed to complete their individual tasks by reaching agreements and exchanging resources, the number of negotiation rounds was not fixed in advance and agreements were not binding. The agent negotiated with human subjects in the United States and Lebanon in situations that varied the dependency relationships between participants at the onset of negotiation. There was no prior data available about the way people would respond to different negotiation strategies in these two countries. Results showed that the agent was able to adopt a different negotiation strategy to each country. Its average performance across both countries was equal to that of people. However, the agent outperformed people in the United States, because it learned to make offers that were likely to be accepted by people, while being more beneficial to the agent than to people. In contrast, the agent was outperformed by people in Lebanon, because it adopted a high reliability measure which allowed people to take advantage of it. These results provide insight for human-computer agent designers in the types of multicultural settings that we considered, showing that adaptation is a viable approach towards the design of computer agents to negotiate with people when there is no prior data of their behavior.
Interactive Image Search by Color Map
Authors: Wang Jingdong , Hua Xian-Sheng
Published: October 2012

The availability of large-scale images from the Internet has made the research on image search attract a lot of attention. Text-based image search engines, for example, Google/Microsoft Bing/Yahoo! image search engines using the surrounding text, have been developed and widely used. However, they suffer from an inability to search image content. In this article, we present an interactive image search system, image search by color map, which can be applied to, but not limited to, enhance text-based image search. This system enables users to indicate how the colors are spatially distributed in the desired images, by scribbling a few color strokes, or dragging an image and highlighting a few regions of interest in an intuitive way. In contrast to the conventional sketch-based image retrieval techniques, our system searches images based on colors rather than shapes, and we, technically, propose a simple but effective scheme to mine the latent search intention from the user’s input, and exploit the dominant color filter strategy to make our system more efficient. We integrate our system to existing Web image search engines to demonstrate its superior performance over text-based image search. The user study shows that our system can indeed help users conveniently find desired images.
Web Page Summarization for Just-in-Time Contextual Advertising
Authors: Anagnostopoulos Aris , Broder Andrei Z. , Gabrilovich Evgeniy , Josifovski Vanja , Riedel Lance
Published: October 2012

Contextual advertising
is a type of Web advertising, which, given the URL of a Web page, aims to embed into the page the most relevant textual ads available. For static pages that are displayed repeatedly, the matching of ads can be based on prior analysis of their entire content; however, often ads need to be matched to new or dynamically created pages that cannot be processed ahead of time. Analyzing the entire content of such pages on-the-fly entails prohibitive communication and latency costs. To solve the three-horned dilemma of either low relevance or high latency or high load, we propose to use text summarization techniques paired with external knowledge (exogenous to the page) to craft short page summaries in real time.

Empirical evaluation proves that matching ads on the basis of such summaries does not sacrifice relevance, and is competitive with matching based on the entire page content. Specifically, we found that analyzing a carefully selected 6% fraction of the page text can sacrifice only 1%--3% in ad relevance. Furthermore, our summaries are fully compatible with the standard JavaScript mechanisms used for ad placement: they can be produced at ad-display time by simple additions to the usual script, and they only add 500--600 bytes to the usual request. We also compared our summarization approach, which is based on structural properties of the HTML content of the page, with a more principled one based on one of the standard text summarization tools (MEAD), and found their performance to be comparable.
Group Profiling for Understanding Social Structures
Authors: Tang Lei , Wang Xufei , Liu Huan
Published: October 2012

The prolific use of participatory Web and social networking sites is reshaping the ways in which people interact with one another. It has become a vital part of human social life in both the developed and developing world. People sharing certain similarities or affiliates tend to form communities within social media. At the same time, they participate in various online activities: content sharing, tagging, posting status updates, etc. These diverse activities leave behind traces of their social life, providing clues to understand changing social structures. A large body of existing work focuses on extracting cohesive groups based on network topology. But little attention is paid to understanding the changing social structures. In order to help explain the formation of a group, we explore different group-profiling strategies to construct descriptions of a group. This research can assist network navigation, visualization, and analysis, as well as monitoring and tracking the ebbs and tides of different groups in evolving networks. By exploiting information collected from real-world social media sites, extensive experiments are conducted to evaluate group-profiling results. The pros and cons of different group-profiling strategies are analyzed with concrete examples. We also show some potential applications based on group profiling. Interesting findings with discussions are reported.
Mining Concept Sequences from Large-Scale Search Logs for Context-Aware Query Suggestion
Authors: Liao Zhen , Jiang Daxin , Chen Enhong , Pei Jian , Cao Huanhuan , Li Hang
Published: October 2012

Query suggestion plays an important role in improving usability of search engines. Although some recently proposed methods provide query suggestions by mining query patterns from search logs, none of them models the immediately preceding queries as context systematically, and uses context information effectively in query suggestions. Context-aware query suggestion is challenging in both modeling context and scaling up query suggestion using context. In this article, we propose a novel context-aware query suggestion approach. To tackle the challenges, our approach consists of two stages. In the first,
offline model-learning stage
, to address data sparseness, queries are summarized into concepts by clustering a click-through bipartite. A
concept sequence suffix tree
is then constructed from session data as a context-aware query suggestion model. In the second,
online query suggestion stage
, a user’s search context is captured by mapping the query sequence submitted by the user to a sequence of concepts. By looking up the context in the concept sequence suffix tree, we suggest to the user context-aware queries. We test our approach on large-scale search logs of a commercial search engine containing 4.0 billion Web queries, 5.9 billion clicks, and 1.87 billion search sessions. The experimental results clearly show that our approach outperforms three baseline methods in both coverage and quality of suggestions.
Activity Recognition for Dynamic Multi-Agent Teams
Authors: Sukthankar Gita , Sycara Katia
Published: October 2012

This article addresses the problem of activity recognition for dynamic, physically embodied agent teams. We define team activity recognition as the process of identifying team behaviors from traces of agent positions over time; for many physical domains, military or athletic, coordinated team behaviors create distinctive spatio-temporal patterns that can be used to identify low-level action sequences. This article focuses on the novel problem of recovering
agent-to-team
assignments for complex team tasks where team composition, the mapping of agents into teams, changes over time. We suggest two methods for improving the computational efficiency of the multi-agent plan recognition process in these cases of changing team composition; our proposed approach is robust to sensor observation noise and errors in behavior classification.
Watch the Story Unfold with TextWheel
Authors: Cui Weiwei , Qu Huamin , Zhou Hong , Zhang Wenbin , Skiena Steve
Published: October 2012

Keyword-based searching and clustering of news articles have been widely used for news analysis. However, news articles usually have other attributes such as source, author, date and time, length, and sentiment which should be taken into account. In addition, news articles and keywords have complicated macro/micro relations, which include relations between news articles (i.e., macro relation), relations between keywords (i.e., micro relation), and relations between news articles and keywords (i.e., macro-micro relation). These macro/micro relations are time varying and pose special challenges for news analysis.

In this article we present a visual analytics system for news streams which can bring multiple attributes of the news articles and the macro/micro relations between news streams and keywords into one coherent analytical context, all the while conveying the dynamic natures of news streams. We introduce a new visualization primitive called TextWheel which consists of one or multiple keyword wheels, a document transportation belt, and a dynamic system which connects the wheels and belt. By observing the TextWheel and its content changes, some interesting patterns can be detected. We use our system to analyze several news corpora related to some major companies and the results demonstrate the high potential of our method.
Visual Abstraction and Ordering in Faceted Browsing of Text Collections
Authors: Thai Vinhtuan , Rouille Pierre-Yves , Handschuh Siegfried
Published: October 2012

Faceted navigation is a technique for the exploration and discovery of a collection of resources, which can be of various types including text documents. While being information-rich resources, documents are usually not treated as content-bearing items in faceted browsing interfaces, and yet the required clean metadata is not always available or matches users’ interest. In addition, the existing linear listing paradigm for representing result items from the faceted filtering process makes it difficult for users to traverse or compare across facet values in different orders of importance to them. In this context, we report in this article a visual support toward faceted browsing of a collection of documents based on a set of entities of interest to users. Our proposed approach involves using a multi-dimensional visualization as an alternative to the linear listing of focus items. In this visualization, visual abstraction based on a combination of a conceptual structure and the structural equivalence of documents can be simultaneously used to deal with a large number of items. Furthermore, the approach also enables visual ordering based on the importance of facet values to support prioritized, cross-facet comparisons of focus items. A user study was conducted and the results suggest that interfaces using the proposed approach can support users better in exploratory tasks and were also well-liked by the participants of the study, with the hybrid interface combining the multi-dimensional visualization with the linear listing receiving the most favorable ratings.
PhC
Authors: Candan K. Selçuk , Di Caro Luigi , Sapino Maria Luisa
Published: October 2012

The high-dimensional nature of the textual data complicates the design of visualization tools to support exploration of large document corpora. In this article, we first argue that the Parallel Coordinates (PC) technique, which can map multidimensional vectors onto a 2D space in such a way that elements with similar values are represented as similar poly-lines or curves in the visualization space, can be used to help users discern patterns in document collections. The inherent reduction in dimensionality during the mapping from multidimensional points to 2D lines, however, may result in visual complications. For instance, the lines that correspond to clusters of objects that are separate in the multidimensional space may overlap each other in the 2D space; the resulting increase in the number of crossings would make it hard to distinguish the individual document clusters. Such crossings of lines and overly dense regions are significant sources of visual clutter, thus avoiding them may help interpret the visualization. In this article, we note that visual clutter can be significantly reduced by adjusting the resolution of the individual term coordinates by clustering the corresponding values. Such reductions in the resolution of the individual term-coordinates, however, will lead to a certain degree of information loss and thus the appropriate resolution for the term-coordinates has to be selected carefully. Thus, in this article we propose a controlled clutter reduction approach, calledParallel hierarchical Coordinates(orPhC), for reducing the visual clutter in PC-based visualizations of text corpora. We define visual clutter and information loss measures and provide extensive evaluations that show that the proposed PhC provides significant visual gains (i.e., multiple orders of reductions in visual clutter) with small information loss during visualization and exploration of document collections.
TopicNets
Authors: Gretarsson Brynjar , O’Donovan John , Bostandjiev Svetlin , Höllerer Tobias , Asuncion Arthur , Newman David , Smyth Padhraic
Published: October 2012

We present
TopicNets
, a Web-based system for visual and interactive analysis of large sets of documents using statistical topic models. A range of visualization types and control mechanisms to support knowledge discovery are presented. These include corpus- and document-specific views, iterative topic modeling, search, and visual filtering. Drill-down functionality is provided to allow analysts to visualize individual document sections and their relations within the global topic space. Analysts can search across a dataset through a set of expansion techniques on selected document and topic nodes. Furthermore, analysts can select relevant subsets of documents and perform real-time topic modeling on these subsets to interactively visualize topics at various levels of granularity, allowing for a better understanding of the documents. A discussion of the design and implementation choices for each visual analysis technique is presented. This is followed by a discussion of three diverse use cases in which TopicNets enables fast discovery of information that is otherwise hard to find. These include a corpus of 50,000 successful NSF grant proposals, 10,000 publications from a large research center, and single documents including a grant proposal and a PhD thesis.
DClusterE
Authors: Zhang Yi , Li Tao
Published: October 2012

Over the last decade, document clustering, as one of the key tasks in information organization and navigation, has been widely studied. Many algorithms have been developed for addressing various challenges in document clustering and for improving clustering performance. However, relatively few research efforts have been reported on evaluating and understanding document clustering results. In this article, we present
DClusterE
, a comprehensive and effective framework for document clustering evaluation and understanding using information visualization.
DClusterE
integrates cluster validation with user interactions and offers rich visualization tools for users to examine document clustering results from multiple perspectives. In particular, through informative views including force-directed layout view, matrix view, and cluster view,
DClusterE
provides not only different aspects of document inter/intra-clustering structures, but also the corresponding relationship between clustering results and the ground truth. Additionally,
DClusterE
supports general user interactions such as zoom in/out, browsing, and interactive access of the documents at different levels. Two new techniques are proposed to implement
DClusterE
: (1) A novel multiplicative update algorithm (MUA) for matrix reordering to generate narrow-banded (or clustered) nonzero patterns from documents. Combined with coarse seriation, MUA is able to provide better visualization of the cluster structures. (2) A Mallows-distance-based algorithm for establishing the relationship between the clustering results and the ground truth, which serves as the basis for coloring schemes. Experiments and user studies are conducted to demonstrate the effectiveness and efficiency of
DClusterE
.
TIARA
Authors: Liu Shixia , Zhou Michelle X. , Pan Shimei , Song Yangqiu , Qian Weihong , Cai Weijia , Lian Xiaoxiao
Published: October 2012

We are building an interactive visual text analysis tool that aids users in analyzing large collections of text. Unlike existing work in visual text analytics, which focuses either on developing sophisticated text analytic techniques or inventing novel text visualization metaphors, ours tightly integrates state-of-the-art text analytics with interactive visualization to maximize the value of both. In this article, we present our work from two aspects. We first introduce an enhanced, LDA-based topic analysis technique that automatically derives a set of topics to summarize a collection of documents and their content evolution over time. To help users understand the complex summarization results produced by our topic analysis technique, we then present the design and development of a time-based visualization of the results. Furthermore, we provide users with a set of rich interaction tools that help them further interpret the visualized results in context and examine the text collection from multiple perspectives. As a result, our work offers three unique contributions. First, we present an enhanced topic modeling technique to provide users with a time-sensitive and more meaningful text summary. Second, we develop an effective visual metaphor to transform abstract and often complex text summarization results into a comprehensible visual representation. Third, we offer users flexible visual interaction tools as alternatives to compensate for the deficiencies of current text summarization techniques. We have applied our work to a number of text corpora and our evaluation shows promise, especially in support of complex text analyses.