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Research Collection School Of Computing and Information Systems

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Exclusive Lasso For Multi-Task Feature Selection, Yang Zhou, Rong Jin, Steven C. H. Hoi May 2010

Exclusive Lasso For Multi-Task Feature Selection, Yang Zhou, Rong Jin, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

We propose a novel group regularization which we call exclusive lasso. Unlike the group lasso regularizer that assumes co-varying variables in groups, the proposed exclusive lasso regularizer models the scenario when variables in the same group compete with each other. Analysis is presented to illustrate the properties of the proposed regularizer. We present a framework of kernel-based multi-task feature selection algorithm based on the proposed exclusive lasso regularizer. An efficient algorithm is derived to solve the related optimization problem. Experiments with document categorization show that our approach outperforms state-of-the-art algorithms for multi-task feature selection.


Learning User Profiles For Personalized Information Dissemination, Ah-Hwee Tan, Christine Teo May 2010

Learning User Profiles For Personalized Information Dissemination, Ah-Hwee Tan, Christine Teo

Research Collection School Of Computing and Information Systems

Personalized information systems represent the recent effort of delivering information to users more effectively in the modern electronic age. This paper illustrates how a supervised Adaptive Resonance Theory (ART) system, known as fuzzy ARAM, can be used to learn user profiles for personalized information dissemination. ARAM learning is on-line, fast, and incremental. Acquisition of new knowledge does not require re-training on previously learned cases. ARAM integrates both user-defined and system-learned knowledge in a single framework. Therefore inconsistency between the two knowledge sources will not arise. ARAM has been used to develop a personalized news system known as PIN. Preliminary experiments …


Awareness 2.0: Staying Aware Of Projects, Developers And Tasks Using Dashboards And Feeds, Christoph Treude, Margaret-Anne Storey May 2010

Awareness 2.0: Staying Aware Of Projects, Developers And Tasks Using Dashboards And Feeds, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Software development teams need to maintain awareness of various different aspects ranging from overall project status and process bottlenecks to current tasks and incoming artifacts. Currently, there is a lack of theoretical foundations to guide tool selection and tool design to best support awareness tasks. In this paper, we explore how the combination of highly configurable project, team and contributor dashboards along with individual event feeds is used to accomplish extensive awareness. Our results stem from an empirical study of several large development teams, with a detailed study of a team of 150 developers and additional data from another four …


Bridging Lightweight And Heavyweight Task Organization: The Role Of Tags In Adopting New Task Categories, Christoph Treude, Margaret-Anne Storey May 2010

Bridging Lightweight And Heavyweight Task Organization: The Role Of Tags In Adopting New Task Categories, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

In collaborative software development projects, tasks are often used as a mechanism to coordinate and track shared development work. Modern development environments provide explicit support for task management where tasks are typically organized and managed through predefined categories. Although there have been many studies that analyze data available from task management systems, there has been relatively little work on the design of task management tools. In this paper we explore how tagging with freely assigned keywords provides developers with a lightweight mechanism to further categorize and annotate development tasks. We investigate how tags that are frequently used over a long …


The Role Of Emergent Knowledge Structures In Collaborative Software Development, Christoph Treude May 2010

The Role Of Emergent Knowledge Structures In Collaborative Software Development, Christoph Treude

Research Collection School Of Computing and Information Systems

Many collaboration features in software development tools draw on lightweight technologies such as tagging and wikis. We propose to study the role of emergent knowledge structures created through these features. Using a mixed-methods approach, we investigate which processes emergent knowledge structures support and how tool support can leverage them.


Web2se: First Workshop On Web 2.0 For Software Engineering, Christoph Treude, Margaret-Anne Storey, Kate Ehrlich, Arie Van Deursen May 2010

Web2se: First Workshop On Web 2.0 For Software Engineering, Christoph Treude, Margaret-Anne Storey, Kate Ehrlich, Arie Van Deursen

Research Collection School Of Computing and Information Systems

Social software is built around an "architecture of participation" where user data is aggregated as a side-effect of using Web 2.0 applications. Web 2.0 implies that processes and tools are socially open, and that content can be used in several different contexts. Web 2.0 tools and technologies support interactive information sharing, data interoperability and user centered design. For instance, wikis, blogs, tags and feeds help us organize, manage and categorize content in an informal and collaborative way. One goal of this workshop is to investigate how these technologies can improve software development practices. Some of these technologies have made their …


Towards Finding Robust Execution Strategies For Rcpsp/Max With Durational Uncertainty, Na Fu, Pradeep Varakantham, Hoong Chuin Lau May 2010

Towards Finding Robust Execution Strategies For Rcpsp/Max With Durational Uncertainty, Na Fu, Pradeep Varakantham, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

Resource Constrained Project Scheduling Problems with minimum and maximum time lags (RCPSP/max) have been studied extensively in the literature. However, the more realistic RCPSP/max problems — ones where durations of activities are not known with certainty – have received scant interest and hence are the main focus of the paper. Towards addressing the significant computational complexity involved in tackling RCPSP/max with durational uncertainty, we employ a local search mechanism to generate robust schedules. In this regard, we make two key contributions: (a) Introducing and studying the key properties of a new decision rule to specify start times of activities with …


Open Innovation In Platform Competition, Mei Lin May 2010

Open Innovation In Platform Competition, Mei Lin

Research Collection School Of Computing and Information Systems

We examine the competition between a proprietary platform and an open platform,where each platform holds a two-sided market consisted of app developers and users.The open platform cultivates an innovative environment by inviting public efforts todevelop the platform itself and permitting distribution of apps outside of its own appmarket; the proprietary platform restricts apps sales solely within its app market. Weuse a game theoretic model to capture this competitive phenomenon and analyze theimpact of growth of the open source community on the platform competition. We foundthat growth of the open community mitigates the platform rivalry, and balances the developernetwork sizes on …


A Discriminative Model Approach For Accurate Duplicate Bug Report Retrieval, Chengnian Sun, David Lo, Xiaoyin Wang, Siau-Cheng Khoo May 2010

A Discriminative Model Approach For Accurate Duplicate Bug Report Retrieval, Chengnian Sun, David Lo, Xiaoyin Wang, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Bug repositories are usually maintained in software projects. Testers or users submit bug reports to identify various issues with systems. Sometimes two or more bug reports correspond to the same defect. To address the problem with duplicate bug reports, a person called a triager needs to manually label these bug reports as duplicates, and link them to their "master" reports for subsequent maintenance work. However, in practice there are considerable duplicate bug reports sent daily; requesting triagers to manually label these bugs could be highly time consuming. To address this issue, recently, several techniques have be proposed using various similarity …


Point-Based Backup For Decentralized Pompds: Complexity And New Algorithms, Akshat Kumar, Shlomo Zilberstein May 2010

Point-Based Backup For Decentralized Pompds: Complexity And New Algorithms, Akshat Kumar, Shlomo Zilberstein

Research Collection School Of Computing and Information Systems

Decentralized POMDPs provide an expressive framework for sequential multi-agent decision making. Despite their high complexity, there has been significant progress in scaling up existing algorithms, largely due to the use of point-based methods. Performing point-based backup is a fundamental operation in state-of-the-art algorithms. We show that even a single backup step in the multi-agent setting is NP-Complete. Despite this negative worst-case result, we present an efficient and scalable optimal algorithm as well as a principled approximation scheme. The optimal algorithm exploits recent advances in the weighted CSP literature to overcome the complexity of the backup operation. The polytime approximation scheme …


Finding Influentials Based On The Temporal Order Of Information Adoption In Twitter, Changhyun Lee, Haewoon Kwak, Hosung Park, Sue Moon Apr 2010

Finding Influentials Based On The Temporal Order Of Information Adoption In Twitter, Changhyun Lee, Haewoon Kwak, Hosung Park, Sue Moon

Research Collection School Of Computing and Information Systems

Twitter offers an explicit mechanism to facilitate information diffusion and has emerged as a new medium for communication. Many approaches to find influentials have been proposed, but they do not consider the temporal order of information adoption. In this work, we propose a novel method to find influentials by considering both the link structure and the temporal order of information adoption in Twitter. Our method finds distinct influentials who are not discovered by other methods.


Mashup Environments In Software Engineering, Lars Grammel, Christoph Treude, Margaret-Anne Storey Apr 2010

Mashup Environments In Software Engineering, Lars Grammel, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Too often, software engineering (SE) tool research is focused on creating small, stand-alone tools that address rarely understood developer needs. We believe that research should instead provide developers with flexible environments and interoperable tools, and then study how developers appropriate and tailor these tools in practice. Although there has been some prior work on this, we feel that flexible tool environments for SE have not yet been fully explored. In particular, we propose adopting the Web 2.0 idea of mashups and mashup environments to support SE practitioners in analytic activities involving multiple information sources.


Efficient Skyline Maintenance For Streaming Data With Partially-Ordered Domains, Yuan Fang, Chee-Yong Chan Apr 2010

Efficient Skyline Maintenance For Streaming Data With Partially-Ordered Domains, Yuan Fang, Chee-Yong Chan

Research Collection School Of Computing and Information Systems

We address the problem of skyline query processing for a count-based window of continuous streaming data that involves both totally- and partially-ordered attribute domains. In this problem, a fixed-size buffer of the N most recent tuples is dynamically maintained and the key challenge is how to efficiently maintain the skyline of the sliding window of N tuples as new tuples arrive and old tuples expire. We identify the limitations of the state-of-the-art approach STARS, and propose two new approaches, STARS+ and SkyGrid, to address its drawbacks. STARS+ is an enhancement of STARS with three new optimization techniques, while SkyGrid is …


Policy-Driven Distributed And Collaborative Demand Response In Multi-Domain Commercial Buildings, Archan Misra, Henning Schulzrinne Apr 2010

Policy-Driven Distributed And Collaborative Demand Response In Multi-Domain Commercial Buildings, Archan Misra, Henning Schulzrinne

Research Collection School Of Computing and Information Systems

Enabling a sophisticated Demand Response (DR) framework, whereby individual consumers adapt their electricity consumption in response to price variations, is a major objective of the emerging Smart Grid. We first point out why the current model, of EMS-based centralized control of a static repository of high load appliances, is inappropriate for supporting DR in future commercial buildings and campuses, where the consuming appliances are controlled by multiple users. To enable DR in such multi-domain environments, we envision a more collaborative and autonomous model, where a large set of heterogeneous smart electrical devices autonomously self-organize and negotiate their collective DR. Enabling …


A Verification System For Interval-Based Specification Languages, Chunqing Chen, Jin Song Dong, Jun Sun, Andrew P. Martin Apr 2010

A Verification System For Interval-Based Specification Languages, Chunqing Chen, Jin Song Dong, Jun Sun, Andrew P. Martin

Research Collection School Of Computing and Information Systems

Interval-based specification languages have been used to formally model and rigorously reason about real-time computing systems. This usually involves logical reasoning and mathematical computation with respect to continuous or discrete time. When these systems are complex, analyzing their models by hand becomes error-prone and difficult. In this article, we develop a verification system to facilitate the formal analysis of interval-based specification languages with machine-assisted proof support. The verification system is developed using a generic theorem prover, Prototype Verification System (PVS). Our system elaborately encodes a highly expressive set-based notation, Timed Interval Calculus (TIC), and can rigorously carry out the verification …


Adaptive Ensemble Classification In P2p Networks, Hock Hee Ang, Vivekanand Gopalkrishnan, Steven C. H. Hoi, Wee Keong Ng Apr 2010

Adaptive Ensemble Classification In P2p Networks, Hock Hee Ang, Vivekanand Gopalkrishnan, Steven C. H. Hoi, Wee Keong Ng

Research Collection School Of Computing and Information Systems

Classification in P2P networks has become an important research problem in data mining due to the popularity of P2P computing environments. This is still an open difficult research problem due to a variety of challenges, such as non-i.i.d. data distribution, skewed or disjoint class distribution, scalability, peer dynamism and asynchronism. In this paper, we present a novel P2P Adaptive Classification Ensemble (PACE) framework to perform classification in P2P networks. Unlike regular ensemble classification approaches, our new framework adapts to the test data distribution and dynamically adjusts the voting scheme by combining a subset of classifiers/peers according to the test data …


Continuous Spatial Assignment Of Moving Users, Hou U Leong, Kyriakos Mouratidis, Nikos Mamoulis Apr 2010

Continuous Spatial Assignment Of Moving Users, Hou U Leong, Kyriakos Mouratidis, Nikos Mamoulis

Research Collection School Of Computing and Information Systems

Consider a set of servers and a set of users, where each server has a coverage region (i.e., an area of service) and a capacity (i.e., a maximum number of users it can serve). Our task is to assign every user to one server subject to the coverage and capacity constraints. To offer the highest quality of service, we wish to minimize the average distance between users and their assigned server. This is an instance of a well-studied problem in operations research, termed optimal assignment. Even though there exist several solutions for the static case (where user locations are fixed), …


Pagesense: Style-Wise Web Page Advertising, Lusong Li, Tao Mei, Xiang Niu, Chong-Wah Ngo Apr 2010

Pagesense: Style-Wise Web Page Advertising, Lusong Li, Tao Mei, Xiang Niu, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper presents an innovative style-wise advertising platform for web page. Web page “style” mainly refers to visual effects, such as color and layout. Unlike the most popular ad-network such as Google AdSense which needs publishers to change the original structure of their pages and define the position and style of the embedded ads manually, stylewise page advertising aims to automatically deliver styleconsistent ads at proper positions within the web page, without breaking the layout of the original page. Our system is motivated from the fact that almost 90% web pages contain blank regions without any content. Given a web …


The Implications Of How We Tag Software Artifacts: Exploring Different Schemata And Metadata For Tags, Christoph Treude, Margaret-Anne Storey Apr 2010

The Implications Of How We Tag Software Artifacts: Exploring Different Schemata And Metadata For Tags, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Social tagging has been adopted by software developers in various contexts from source code to work items and build definitions. While the success of tagging is usually attributed to the simplicity of tags, the implementation details of tagging systems vary significantly in terms of metadata, schemata and semantics. In this position paper, we argue that academia and industry should be aware of these differences and that we should start to examine their implications.


A Social Network Based Study Of Software Team Dynamics, Subhajit Datta, Vikrant S. Kaulgoud, Vibhu Saujanya Sharma, Nishant Kumar Apr 2010

A Social Network Based Study Of Software Team Dynamics, Subhajit Datta, Vikrant S. Kaulgoud, Vibhu Saujanya Sharma, Nishant Kumar

Research Collection School Of Computing and Information Systems

Members of software project teams have specific roles and responsibilities which are formally defined during project inception or at the start of a life cycle activity. Often, the team structure undergoes spontaneous changes as delivery deadlines draw near and critical tasks have to be completed. Some members -- depending on their skill or seniority -- need to take on more responsibilities, while others end up being peripheral to the project's execution. We posit that this kind of ad hoc reorganization of a team's structure can be discerned from the project's bug tracker. In this paper, we extract a social network …


What Is Twitter, A Social Network Or A News Media?, Haewoon Kwak, Changhyun Lee, Hosung: Moon Park Apr 2010

What Is Twitter, A Social Network Or A News Media?, Haewoon Kwak, Changhyun Lee, Hosung: Moon Park

Research Collection School Of Computing and Information Systems

Twitter, a microblogging service less than three years old, commands more than 41 million users as of July 2009 and is growing fast. Twitter users tweet about any topic within the 140-character limit and follow others to receive their tweets. The goal of this paper is to study the topological characteristics of Twitter and its power as a new medium of information sharing.We have crawled the entire Twitter site and obtained 41.7 million user profiles, 1.47 billion social relations, 4,262 trending topics, and 106 million tweets. In its follower-following topology analysis we have found a non-power-law follower distribution, a short …


Information Search Patterns In E-Commerce Product Comparison Services, Fiona Fui-Hoon Nah, Weiyin Hong, Liqiang Chen, Hong-Hee Lee Apr 2010

Information Search Patterns In E-Commerce Product Comparison Services, Fiona Fui-Hoon Nah, Weiyin Hong, Liqiang Chen, Hong-Hee Lee

Research Collection School Of Computing and Information Systems

To facilitate product selection and purchase decisions on e-commerce Web sites, the presentation of product information is very important. In this research, the authors study how disposition styles influence users’ search patterns in product comparison services of e-commerce Web sites. The results show that people use relatively more feature paths and less product paths in vertical disposition style than horizontal disposition style. The findings also indicate that there are relatively more feature paths and less product paths in the first half than second half of the information search paths. This is consistent with Gensch’s two-stage choice model which suggests that …


Playing With Recognizers: A Call For An Extensible Editor, Richard C. Davis Apr 2010

Playing With Recognizers: A Call For An Extensible Editor, Richard C. Davis

Research Collection School Of Computing and Information Systems

The sketch recognition interface community has not produced a -killer‖ application, because access to sketch recognition technology has been too restricted. If recognition technologies were more freely available for experimentation, powerful new applications would evolve. This paper proposes a rough architecture for an extensible graphical editor that facilitates collaboration between recognition technology developers, user interface designers, and early adopters of sketch recognition interfaces. Only by serving all three communities will we reach the critical mass necessary for killer applications to emerge.


Managing Media Rich Geo-Spatial Annotations For A Map-Based Mobile Application Using Clustering, Khasfariyati Razikin, Dion Hoe-Lian Goh, Ee Peng Lim, Aixin Sun, Yin-Leng Theng, Thi Nhu Quynh Kim, Kalyani Chatterjea, Chew-Hung Chang Apr 2010

Managing Media Rich Geo-Spatial Annotations For A Map-Based Mobile Application Using Clustering, Khasfariyati Razikin, Dion Hoe-Lian Goh, Ee Peng Lim, Aixin Sun, Yin-Leng Theng, Thi Nhu Quynh Kim, Kalyani Chatterjea, Chew-Hung Chang

Research Collection School Of Computing and Information Systems

With the prevalence of mobile devices that are equipped with wireless Internet capabilities and Global Positioning System (GPS) functionality, the creation and access of user-generated content are extended to users on the go. Such content are tied to real world objects, in the form of geospatial annotations, and it is only natural that these annotations are visualized using a map-based approach. However, viewing maps that are filled with annotations could hinder the serendipitous discovery of data, especially on the small screens of mobile devices. This calls for a need to manage the annotations. In this paper, we introduce a mobile …


Shifting Inference Control To User Side: Architecture And Protocol, Yanjiang Yang, Yingjiu Li, Robert H. Deng, Feng Bao Apr 2010

Shifting Inference Control To User Side: Architecture And Protocol, Yanjiang Yang, Yingjiu Li, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Inference has been a longstanding issue in database security, and inference control, aiming to curb inference, provides an extra line of defense to the confidentiality of databases by complementing access control. However, in traditional inference control architecture, database server is a crucial bottleneck, as it enforces highly computation-intensive auditing for all users who query the protected database. As a result, most auditing methods, though rigorously studied, are not practical for protecting large-scale real-world database systems. In this paper, we shift this paradigm by proposing a new inference control architecture, entrusting inference control to each user's platform that is equipped with …


Generating Synonyms Based On Query Log Data, Stelios Paparizos, Tao Cheng, Hady W. Lauw Apr 2010

Generating Synonyms Based On Query Log Data, Stelios Paparizos, Tao Cheng, Hady W. Lauw

Research Collection School Of Computing and Information Systems

An approach is described for generating synonyms to supplement at least one information item, such as, in one case, a set of related items. The approach can involve an expansion phase, a clean-up phase, and a reduction phase. In the expansion phase, the approach identifies, for each related item, a set of initial synonym candidates. In the clean-up phase, the approach removes noise from the set of initial synonym candidates (if such noise exists), to provide a set of filtered synonym candidate items. In the reduction phase, the approach ranks and applies a threshold (or thresholds) to the set of …


Data Mining Based Predictive Models For Overall Health Indices, Ridhima Rajkumar, Kyong Jin Shim, Jaideep Srivastava Apr 2010

Data Mining Based Predictive Models For Overall Health Indices, Ridhima Rajkumar, Kyong Jin Shim, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

In this study, we infer health care indices of individuals using their pharmacy medical and prescription claims. Specifically, we focus on the widely used Charlson Index. We use data mining techniques to formulate the problem of classifying Charlson Index (CI) and build predictive models to predict individual health index score. First, we present comparative analyses of several classification algorithms. Second, our study shows that certain ensemble algorithms lead to higher prediction accuracy in comparison to base algorithms. Third, we introduce cost-sensitive learning to the classification algorithms and show that the inclusion of cost-sensitive learning leads to improved prediction accuracy. The …


Model-Based Methods For Linking Web Service Choreography And Orchestration, Jun Sun, Yang Liu, Jin Song Dong, Geguang Pu, Tian Huat Tan Mar 2010

Model-Based Methods For Linking Web Service Choreography And Orchestration, Jun Sun, Yang Liu, Jin Song Dong, Geguang Pu, Tian Huat Tan

Research Collection School Of Computing and Information Systems

In recent years, many Web service composition languages have been proposed. Web service choreography describes collaboration protocols of cooperating Web service participants from a global view. Web service orchestration describes collaboration of the Web services in predefined patterns based on local decision about their interactions with one another at the message/execution level. In this work, we present model-based methods to close the gap between the two views. Building on the strength of model checking techniques, Web service choreography and orchestration are verified against temporal properties or against each other (to show that they are consistent). Specialized optimization techniques are developed …


Cca-Secure Unidirectional Proxy Re-Encryption In The Adaptive Corruption Model Without Random Oracles, Jian Weng, Minrong Chen, Yanjiang Yang, Robert H. Deng, Kefei Chen Mar 2010

Cca-Secure Unidirectional Proxy Re-Encryption In The Adaptive Corruption Model Without Random Oracles, Jian Weng, Minrong Chen, Yanjiang Yang, Robert H. Deng, Kefei Chen

Research Collection School Of Computing and Information Systems

Proxy re-encryption (PRE), introduced by Blaze, Bleumer and Strauss in Eurocrypt’98, allows a semitrusted proxy to convert a ciphertext originally intended for Alice into an encryption of the same message intended for Bob. PRE has recently drawn great interest, and many interesting PRE schemes have been proposed. However, up to now, it is still an important question to come up with a chosen-ciphertext secure unidirectional PRE in the adaptive corruption model. To address this problem, we propose a new unidirectional PRE scheme, and prove its chosen-ciphertext security in the adaptive corruption model without random oracles. Compared with the best known …


A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong Mar 2010

A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong

Research Collection School Of Computing and Information Systems

This paper presents a self-organizing neural architecture that integrates the features of belief, desire, and intention (BDI) systems with reinforcement learning. Based on fusion Adaptive Resonance Theory (fusion ART), the proposed architecture provides a unified treatment for both intentional and reactive cognitive functionalities. Operating with a sense-act-learn paradigm, the low level reactive module is a fusion ART network that learns action and value policies across the sensory, motor, and feedback channels. During performance, the actions executed by the reactive module are tracked by a high level intention module (also a fusion ART network) that learns to associate sequences of actions …