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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 …


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.


Global Project Management: Pedagogy For Distributed Teams, Benjamin Kok Siew Gan, Randy Weinberg, Selma Limam Mansar May 2010

Global Project Management: Pedagogy For Distributed Teams, Benjamin Kok Siew Gan, Randy Weinberg, Selma Limam Mansar

Research Collection School Of Computing and Information Systems

This paper reflects on pedagogy for teaching collaborative global projects across universities in different countries. Over a period of four years, students at three universities - one in the United States, one in Singapore and one in the Middle East - enrolled in a course called "Global Project Management". In this course, coordinated across locations, students experience a global project with distant team members. We describe the course experience and student perceptions of the requisite skills, collaboration tools and challenges bearing on effective global project work.


A Scalable And Energy-Efficient Context Monitoring Framework For Mobile Personal Sensor Networks, Seungwoo Kang, Jinwon Lee, Hyukjae Jang, Youngki Lee, Souneil Park, Junehwa Song May 2010

A Scalable And Energy-Efficient Context Monitoring Framework For Mobile Personal Sensor Networks, Seungwoo Kang, Jinwon Lee, Hyukjae Jang, Youngki Lee, Souneil Park, Junehwa Song

Research Collection School Of Computing and Information Systems

The key feature of many emerging pervasive computing applications is to proactively provide services to mobile individuals. One major challenge in providing users with proactive services lies in continuously monitoring users’ context based on numerous sensors in their PAN/BAN environments. The context monitoring in such environments imposes heavy workloads on mobile devices and sensor nodes with limited computing and battery power. We present SeeMon, a scalable and energy-efficient context monitoring framework for sensor-rich, resource-limited mobile environments. Running on a personal mobile device, SeeMon effectively performs context monitoring involving numerous sensors and applications. On top of SeeMon, multiple applications on the …


Understanding The Values Of Mobile Technology In Education: A Value-Focused Thinking Approach, Hong Sheng, Keng Siau, Fiona Nah May 2010

Understanding The Values Of Mobile Technology In Education: A Value-Focused Thinking Approach, Hong Sheng, Keng Siau, Fiona Nah

Research Collection School Of Computing and Information Systems

Mobile technology has mobilized the human interaction in all dimensions by supporting mobile collaboration. As collaboration is key to learning in today's educational environment, mobile technology has tremendous potential in supporting and improving education and its delivery. Given that mobile technology for education is a new phenomenon that is gaining popularity, the values of using mobile technology to support education need to be further researched and better understood. In this research, we used the Value-Focused Thinking approach to interview students and instructors to identify the values of education that are enabled by mobile technology. These values are represented in the …


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 …


Two-View Transductive Support Vector Machines, Guangxia Li, Steven C. H. Hoi, Kuiyu Chang May 2010

Two-View Transductive Support Vector Machines, Guangxia Li, Steven C. H. Hoi, Kuiyu Chang

Research Collection School Of Computing and Information Systems

Obtaining high-quality and up-to-date labeled data can be difficult in many real-world machine learning applications, especially for Internet classification tasks like review spam detection, which changes at a very brisk pace. For some problems, there may exist multiple perspectives, so called views, of each data sample. For example, in text classification, the typical view contains a large number of raw content features such as term frequency, while a second view may contain a small but highly-informative number of domain specific features. We thus propose a novel two-view transductive SVM that takes advantage of both the abundant amount of unlabeled data …


A Comparative Exploration Of Freebsd Bug Lifetimes, Gargi Bougie, Christoph Treude, Daniel M. Germán, Margaret-Anne Storey May 2010

A Comparative Exploration Of Freebsd Bug Lifetimes, Gargi Bougie, Christoph Treude, Daniel M. Germán, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

In this paper, we explore the viability of mining the basic data provided in bug repositories to predict bug lifetimes. We follow the method of Lucas D. Panjer as described in his paper, Predicting Eclipse Bug Lifetimes. However, in place of Eclipse data, the FreeBSD bug repository is used. We compare the predictive accuracy of five different classification algorithms applied to the two data sets. In addition, we propose future work on whether there is a more informative way of classifying bugs than is considered by current bug tracking systems.


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 …


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 …


Observing And Modeling The Nocturnal Park Cool Island Of An Arid City: Horizontal And Vertical Impacts, Winston T. L. Chow, Ronald L. Pope, Anthony J. Brazel May 2010

Observing And Modeling The Nocturnal Park Cool Island Of An Arid City: Horizontal And Vertical Impacts, Winston T. L. Chow, Ronald L. Pope, Anthony J. Brazel

Research Collection School of Social Sciences

We examined the horizontal and vertical nocturnal cooling influence of a small park with irrigated lawn and xeric surfaces (∼3 ha) within a university campus of a hot arid city. Temperature data from 0.01- to 3-m heights observed during a bicycle traverse of the campus were combined with modeled spatial temperature data simulated from a three-dimensional microclimate model (ENVI-met 3.1). A distinct park cool island, with mean observed magnitudes of 0.7–3.6°C, was documented for both traverse and model data with larger cooling intensities measured closer to surface level. Modeled results possessed varying but generally reasonable accuracy in simulating both spatial …


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 …


Innovative Entrepreneurs Workbook, Arcot Desai Narasimhalu May 2010

Innovative Entrepreneurs Workbook, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

The workbook provides a step by step approach to identifying innovation opportunities and the key aspects of Innovation development


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 …


Time-Bound Hierarchical Key Assignment: An Overview, Wen Tao Zhu, Robert H. Deng, Jianying Zhou, Feng Bao May 2010

Time-Bound Hierarchical Key Assignment: An Overview, Wen Tao Zhu, Robert H. Deng, Jianying Zhou, Feng Bao

Research Collection School Of Computing and Information Systems

The access privileges in distributed systems can be effectively organized as a partial-order hierarchy that consists of distinct security classes, and the access rights are often designated with certain temporal restrictions. The time-bound hierarchical key assignment problem is to assign distinct cryptographic keys to distinct security classes according to their privileges so that users from a higher class can use their class key to derive the keys of lower classes, and these keys are time-variant with respect to sequentially allocated temporal units called time slots. In this paper, we present the involved principle, survey the state of the art, and …


Applying Knowledge Management In University Research, Benjamin Loh, Ai-Chee Tang, Thomas Menkhoff, Hans-Dieter Evers May 2010

Applying Knowledge Management In University Research, Benjamin Loh, Ai-Chee Tang, Thomas Menkhoff, Hans-Dieter Evers

Research Collection Lee Kong Chian School Of Business

In the knowledge-based economy, universities are encountering dramatic changes. Their missions and functions are ‘pragmatized’ because of emerging new players and competing markets for knowledge production, the availability of higher education to a wider range of social classes and age groups, as well as the assimilation of information technology into the university environment. The dynamics and conduct of university research, in particular, has correspondingly become more sensitive to industry collaboration opportunities, commercial exploitation, and is increasingly transdisciplinary. This paper argues that knowledge management (KM) practices and tools can support universities in addressing these demands. Institutions of higher education can benefit …


Efficient Unidirectional Proxy Re-Encryption, Sherman Chow, Weng Jian, Yanjiang Yang, Robert H. Deng May 2010

Efficient Unidirectional Proxy Re-Encryption, Sherman Chow, Weng Jian, Yanjiang Yang, Robert H. Deng

Research Collection School Of Computing and Information Systems

Proxy re-encryption (PRE) allows a semi-trusted proxy to convert a ciphertext originally intended for Alice into one encrypting the same plaintext for Bob. The proxy only needs a re-encryption key given by Alice, and cannot learn anything about the plaintext encrypted. This adds flexibility in various applications, such as confidential email, digital right management and distributed storage. In this paper, we study unidirectional PRE, which the re-encryption key only enables delegation in one direction but not the opposite. In PKC 2009, Shao and Cao proposed a unidirectional PRE assuming the random oracle. However, we show that it is vulnerable to …


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.


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.


Mining Diversity On Networks, Lu Liu, Feida Zhu, Chen Chen, Xifeng Yan, Jiawei Han, Philip Yu, Shiqiang Yang Apr 2010

Mining Diversity On Networks, Lu Liu, Feida Zhu, Chen Chen, Xifeng Yan, Jiawei Han, Philip Yu, Shiqiang Yang

Research Collection School Of Computing and Information Systems

Despite the recent emergence of many large-scale networks in different application domains, an important measure that captures a participant’s diversity in the network has been largely neglected in previous studies. Namely, diversity characterizes how diverse a given node connects with its peers. In this paper, we give a comprehensive study of this concept. We first lay out two criteria that capture the semantic meaning of diversity, and then propose a compliant definition which is simple enough to embed the idea. An efficient top-k diversity ranking algorithm is developed for computation on dynamic networks. Experiments on both synthetic and real datasets …


Do You Trust To Get Trust? A Study Of Trust Reciprocity Behaviors And Reciprocal Trust Prediction, Viet-An Nguyen, Ee Peng Lim, Hwee Hoon Tan, Jing Jiang, Aixin Sun Apr 2010

Do You Trust To Get Trust? A Study Of Trust Reciprocity Behaviors And Reciprocal Trust Prediction, Viet-An Nguyen, Ee Peng Lim, Hwee Hoon Tan, Jing Jiang, Aixin Sun

Research Collection School Of Computing and Information Systems

Trust reciprocity, a special form of link reciprocity, exists in many networks of trust among users. In this paper, we seek to determine the extent to which reciprocity exists in a trust network and develop quantitative models for measuring reciprocity and reciprocity related behaviors. We identify several reciprocity behaviors and their respective measures. These behavior measures can be employed for predicting if a trustee will return trust to her trustor given that the latter initiates a trust link earlier. We develop for this reciprocal trust prediction task a number of ranking method and classification methods, and evaluated them on an …


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 …


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 …


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.


Questioning Thomas Pogge's Proposals To Eradicate Global Poverty, Eduard Jordaan Apr 2010

Questioning Thomas Pogge's Proposals To Eradicate Global Poverty, Eduard Jordaan

Research Collection School of Social Sciences

Moral cosmopolitanism has often been criticised for being too demanding and not offering a viable solution to the problem of extreme global poverty. Thomas Pogge has responded to both these concerns by arguing that it is possible to eradicate most global poverty through relatively light international-level actions. Pogge's proposals can be divided into two broad categories: financial transfers to the poor and international institutional reforms (which include changing the rules of global trade and restricting the ability of undemocratic governments to borrow internationally or sell off their country's natural resources). However, Pogge's proposed international-level actions are unlikely to eradicate global …


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), …


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 …


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 …