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An Investigation Into The Continued Use Of Unified Modeling Language (Uml) In Information Systems Development, Keng Siau, X. Tan Aug 2005

An Investigation Into The Continued Use Of Unified Modeling Language (Uml) In Information Systems Development, Keng Siau, X. Tan

Research Collection School Of Computing and Information Systems

As the de facto standard for object-oriented modeling language, UML is expected to play an increasingly important role in information systems development. The long-term viability and eventual success of UML depend, to a great extent, on the continued use by UML users such as developers and analysts. Systematic investigations on UML’s continued use have been missing from contemporary discussions. Our study attempts to fill this gap in the literature. We developed a research model, which is primarily based on the Expectation Disconfirmation Theory (EDT). According to this model, UML users’ perceived discrepancy between pre-adoption expectation and post-adoption perceived performance, which …


A Semiotics View Of Modeling Method Complexity – The Case Of Uml, Keng Siau, Y. Tian Aug 2005

A Semiotics View Of Modeling Method Complexity – The Case Of Uml, Keng Siau, Y. Tian

Research Collection School Of Computing and Information Systems

Unified Modeling Language (UML) is the standard modeling language for object oriented system development. Despite its status as a standard, UML’s formal specification is fuzzy and its theoretical foundation is weak. Semiotics, the study of signs, provides us good theoretical foundation for UML research as UML graphical notations are some kinds of signs. In this research, we use semiotics to study the graphical notations in UML. We hypothesized that using iconic signs as UML graphical notations leads to more accurate representation and arouses fewer connotations than using symbolic signs. Since symbolic signs involve more learning efforts, we assume that expert …


Constrained Shortest Path Computation, Manolis Terrovitis, Spiridon Bakiras, Dimitris Papadias, Kyriakos Mouratidis Aug 2005

Constrained Shortest Path Computation, Manolis Terrovitis, Spiridon Bakiras, Dimitris Papadias, Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

This paper proposes and solves a-autonomy and k-stops shortest path problems in large spatial databases. Given a source s and a destination d, an aautonomy query retrieves a sequence of data points connecting s and d, such that the distance between any two consecutive points in the path is not greater than a. A k-stops query retrieves a sequence that contains exactly k intermediate data points. In both cases our aim is to compute the shortest path subject to these constraints. Assuming that the dataset is indexed by a data-partitioning method, the proposed techniques initially compute a sub-optimal path by …


Web Mining - The Ontology Approach, Ee Peng Lim, Aixin Sun Aug 2005

Web Mining - The Ontology Approach, Ee Peng Lim, Aixin Sun

Research Collection School Of Computing and Information Systems

The World Wide Web today provides users access to extremely large number of Web sites many of which contain information of education and commercial values. Due to the unstructured and semi-structured nature of Web pages and the design idiosyncrasy of Web sites, it is a challenging task to develop digital libraries for organizing and managing digital content from the Web. Web mining research, in its last 10 years, has on the other hand made significant progress in categorizing and extracting content from the Web. In this paper, we represent ontology as a set of concepts and their inter-relationships relevant to …


Tuning Tabu Search Strategies Via Visual Diagnosis, Steven Halim, Wee Chong Wan, Hoong Chuin Lau Aug 2005

Tuning Tabu Search Strategies Via Visual Diagnosis, Steven Halim, Wee Chong Wan, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

While designing working metaheuristics can be straightforward, tuning them to solve the underlying combinatorial optimization problem well can be tricky. Several tuning methods have been proposed but they do not address the new aspect of our proposed classification of the metaheuristic tuning problem: tuning search strategies. We propose a tuning methodology based on Visual Diagnosis and a generic tool called Visualizer for Metaheuristics Development Framework(V-MDF) to address specifically the problem of tuning search (particularly Tabu Search) strategies. Under V-MDF, we propose the use of a Distance Radar visualizer where the human and computer can collaborate to diagnose the occurrence of …


Wmxml: A System For Watermarking Xml Data, Xuan Zhou, Hwee Hwa Pang, Kian-Lee Tan, Dhruv Mangla Aug 2005

Wmxml: A System For Watermarking Xml Data, Xuan Zhou, Hwee Hwa Pang, Kian-Lee Tan, Dhruv Mangla

Research Collection School Of Computing and Information Systems

As increasing amount of data is published in the form of XML, copyright protection of XML data is becoming an important requirement for many applications. While digital watermarking is a widely used measure to protect digital data from copyright offences, the complex and flexible construction of XML data poses a number of challenges to digital watermarking, such as re-organization and alteration attacks. To overcome these challenges, the watermarking scheme has to be based on the usability of data and the underlying semantics like key attributes and functional dependencies. In this paper, we describe WmXML, a system for watermarking XML documents. …


Translation Initiation Sites Prediction With Mixture Gaussian Models In Human Cdna Sequences, G. Li, Tze-Yun Leong, Louxin Zhang Aug 2005

Translation Initiation Sites Prediction With Mixture Gaussian Models In Human Cdna Sequences, G. Li, Tze-Yun Leong, Louxin Zhang

Research Collection School Of Computing and Information Systems

Translation initiation sites (TISs) are important signals in cDNA sequences. Many research efforts have tried to predict TISs in cDNA sequences. In this paper, we propose to use mixture Gaussian models for TIS prediction. Using both local features and some features generated from global measures, the proposed method predicts TISs with a sensitivity of 98 percent and a specificity of 93.6 percent. Our method outperforms many other existing methods in sensitivity while keeping specificity high. We attribute the improvement in sensitivity to the nature of the global features and the mixture Gaussian models. © 2005 IEEE.


Descriptive Naming Of Context Data Providers, Norman H. Cohen, Paul Castro, Archan Misra Jul 2005

Descriptive Naming Of Context Data Providers, Norman H. Cohen, Paul Castro, Archan Misra

Research Collection School Of Computing and Information Systems

Much context data comes from mobile, transient, and unreliable sources. Such resources are best specified by descriptive names identifying what data is needed rather than which source is to provide it. The design of descriptive names has important consequences, but until now little attention has been focused on this problem. We propose a descriptive naming system for providers of context data that provides more flexibility and power than previous naming systems by classifying data providers into “provider kinds” that are organized in an evolving hierarchy of subkinds and superkinds. New provider kinds can be inserted in the hierarchy not only …


Approximate Strategic Reasoning Through Hierarchical Reduction Of Large Symmetric Games, Michael P. Wellman, Daniel M. Reeves, Kevin M. Lochner, Shih-Fen Cheng, Rahul Suri Jul 2005

Approximate Strategic Reasoning Through Hierarchical Reduction Of Large Symmetric Games, Michael P. Wellman, Daniel M. Reeves, Kevin M. Lochner, Shih-Fen Cheng, Rahul Suri

Research Collection School Of Computing and Information Systems

To deal with exponential growth in the size of a game with the number of agents, we propose an approximation based on a hierarchy of reduced games. The reduced game achieves savings by restricting the number of agents playing any strategy to fixed multiples. We validate the idea through experiments on randomly generated local-effect games. An extended application to strategic reasoning about a complex trading scenario motivates the approach, and demonstrates methods for game-theoretic reasoning over incompletely-specified games at multiple levels of granularity.


An Informatization Of Society Approach To E-Government: Analyzing Singapore’S E-Government Efforts, Calvin M. L. Chan, Yi Meng Lau Jul 2005

An Informatization Of Society Approach To E-Government: Analyzing Singapore’S E-Government Efforts, Calvin M. L. Chan, Yi Meng Lau

Research Collection School Of Computing and Information Systems

Despite the much publicized benefits of e-government, many countries are experiencing difficulty in yielding success in their e-government initiatives. Studies which adopt the national e-government initiatives as the unit of analysis remain largely rare. This paper aspires to provide an analysis of Singapore’s widely acclaimed success in the e-government effort at the national level to allow other countries to learn and gain from its experience. Using the ‘Conceptual Framework for the Informatization of Society’ in facilitating the data analysis, implications are drawn to offer insights for the considerations of e-government practitioners. Theoretical implications are also derived through positing that the …


Strategic Assessment Of Information Security Maturity, Arcot Desai Narasimhalu, Dayasindhu Nagarajan, Raghavan Subramanian Jul 2005

Strategic Assessment Of Information Security Maturity, Arcot Desai Narasimhalu, Dayasindhu Nagarajan, Raghavan Subramanian

Research Collection School Of Computing and Information Systems

CXOs are becoming increasingly interested in the information security maturity of their enterprises. This paper presents a CXO dashboard that will allow better management of the information security resources in an enterprise.


Exploiting Belief Bounds: Practical Pomdps For Personal Assistant Agents, Pradeep Varakantham, Rajiv Maheswaran, Milind Tambe Jul 2005

Exploiting Belief Bounds: Practical Pomdps For Personal Assistant Agents, Pradeep Varakantham, Rajiv Maheswaran, Milind Tambe

Research Collection School Of Computing and Information Systems

Agents or agent teams deployed to assist humans often face the challenges of monitoring the state of key processes in their environment (including the state of their human users themselves) and making periodic decisions based on such monitoring. POMDPs appear well suited to enable agents to address these challenges, given the uncertain environment and cost of actions, but optimal policy generation for POMDPs is computationally expensive. This paper introduces three key techniques to speedup POMDP policy generation that exploit the notion of progress or dynamics in personal assistant domains. Policy computation is restricted to the belief space polytope that remains …


Social Network Discovery By Mining Spatio-Temporal Events, Hady Lauw, Ee Peng Lim, Hwee Hwa Pang, Teck-Tim Tan Jul 2005

Social Network Discovery By Mining Spatio-Temporal Events, Hady Lauw, Ee Peng Lim, Hwee Hwa Pang, Teck-Tim Tan

Research Collection School Of Computing and Information Systems

Knowing patterns of relationship in a social network is very useful for law enforcement agencies to investigate collaborations among criminals, for businesses to exploit relationships to sell products, or for individuals who wish to network with others. After all, it is not just what you know, but also whom you know, that matters. However, finding out who is related to whom on a large scale is a complex problem. Asking every single individual would be impractical, given the huge number of individuals and the changing dynamics of relationships. Recent advancement in technology has allowed more data about activities of individuals …


Middleware Architecture For Evaluation And Selection Of 3rd Party Web Services For Service Providers, Dipanjan Chakraborty, Suraj K. Jaiswal, Archan Misra, Amit A. Nanavati Jul 2005

Middleware Architecture For Evaluation And Selection Of 3rd Party Web Services For Service Providers, Dipanjan Chakraborty, Suraj K. Jaiswal, Archan Misra, Amit A. Nanavati

Research Collection School Of Computing and Information Systems

This paper presents an architecture to facilitate efficient evaluation and selection of 3rd party Web services for service providers. Most service provider architectures have primarily focused on providing Web service front ends to legacy systems, aggregating and delivering services via workflows. These architectures primarily considered static business contracts between the service provider and its (Web-service enabled) business partners. This approach makes these architectures inflexible to variations in business requirement, partners' performance and customer requirements. Our architecture provides a flexible means for service providers to optimize business performance. Based on the historical performance, extant context, and optimising business rules, the appropriate …


Synthesis Of Distributed Processes From Scenario-Based Specifications, Jun Sun, Jin Song Dong Jul 2005

Synthesis Of Distributed Processes From Scenario-Based Specifications, Jun Sun, Jin Song Dong

Research Collection School Of Computing and Information Systems

Given a set of sequence diagrams, the problem of synthesis is of deciding whether there exists a satisfying object system and if so, synthesize one automatically. It is crucial in the development of complex systems, since sequence diagrams serve as the manifestation of use cases and if synthesizable they could lead directly to implementation. It is even more interesting (and harder) if the synthesized object system is distributed. In this paper, we propose a systematic way of synthesizing distributed processes from Live Sequence Charts. The basic idea is to first construct a CSP specification from the LSC specification, and then …


Evaluating G-Portal For Geography Learning And Teaching, Chew-Hung Chang, John G. Hedberg, Yin-Leng Theng, Ee Peng Lim, Tiong-Sa Teh, Dion Hoe-Lian Goh Jun 2005

Evaluating G-Portal For Geography Learning And Teaching, Chew-Hung Chang, John G. Hedberg, Yin-Leng Theng, Ee Peng Lim, Tiong-Sa Teh, Dion Hoe-Lian Goh

Research Collection School Of Computing and Information Systems

This paper describes G-Portal, a geospatial digital library of geographical assets, providing an interactive platform to engage students in active manipulation and analysis of information resources and collaborative learning activities. Using a G-Portal application in which students conducted a field study of an environmental problem of beach erosion and sea level rise, we describe a pilot study to evaluate usefulness and usability issues to support the learning of geographical concepts, and in turn teaching.


On Assigning Place Names To Geography Related Web Pages, Wenbo Zong, Dan Wu, Aixin Sun, Ee Peng Lim, Dion Hoe-Lian Goh Jun 2005

On Assigning Place Names To Geography Related Web Pages, Wenbo Zong, Dan Wu, Aixin Sun, Ee Peng Lim, Dion Hoe-Lian Goh

Research Collection School Of Computing and Information Systems

In this paper, we attempt to give spatial semantics to web pages by assigning them place names. The entire assignment task is divided into three sub-problems, namely place name extraction, place name disambiguation and place name assignment. We propose our approaches to address these sub-problems. In particular, we have modified GATE, a well-known named entity extraction software, to perform place name extraction using a US Census gazetteer. A rule-based place name disambiguation method and a place name assignment method capable of assigning place names to web page segments have also been proposed. We have evaluated our proposed disambiguation and assignment …


Verifying Completeness Of Relational Query Results In Data Publishing, Hwee Hwa Pang, Arpit Jain, Krithi Ramamritham, Kian-Lee Tan Jun 2005

Verifying Completeness Of Relational Query Results In Data Publishing, Hwee Hwa Pang, Arpit Jain, Krithi Ramamritham, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

In data publishing, the owner delegates the role of satisfying user queries to a third-party publisher. As the publisher may be untrusted or susceptible to attacks, it could produce incorrect query results. In this paper, we introduce a scheme for users to verify that their query results are complete (i.e., no qualifying tuples are omitted) and authentic (i.e., all the result values originated from the owner). The scheme supports range selection on key and non-key attributes, project as well as join queries on relational databases. Moreover, the proposed scheme complies with access control policies, is computationally secure, and can be …


Aggregate Nearest Neighbor Queries In Spatial Databases, Dimitris Papadias, Yufei Tao, Kyriakos Mouratidis, Chun Kit Hui Jun 2005

Aggregate Nearest Neighbor Queries In Spatial Databases, Dimitris Papadias, Yufei Tao, Kyriakos Mouratidis, Chun Kit Hui

Research Collection School Of Computing and Information Systems

Given two spatial datasets P (e.g., facilities) and Q (queries), an aggregate nearest neighbor (ANN) query retrieves the point(s) of P with the smallest aggregate distance(s) to points in Q. Assuming, for example, n users at locations q1,...qn, an ANN query outputs the facility p belongs to P that minimizes the sum of distances |pqi| for 1 is less than or equal to i is less than or equal to n that the users have to travel in order to meet there. Similarly, another ANN query may report the point p belongs to P that minimizes the maximum distance that …


Dsi: A Fully Distributed Spatial Index For Wireless Data Broadcast, Wang-Chien Lee, Baihua Zheng Jun 2005

Dsi: A Fully Distributed Spatial Index For Wireless Data Broadcast, Wang-Chien Lee, Baihua Zheng

Research Collection School Of Computing and Information Systems

Recent announcement of the MSN Direct Service has demonstrated the feasibility and industrial interest in utilizing wireless broadcast for pervasive information services. To support location-based services in wireless data broadcast systems, a distributed spatial index (called DSI) is proposed in this paper. DSI is highly efficient because it has a linear yet fully distributed structure that facilitates multiple search paths to be naturally mixed together by sharing links. Moreover, DSI is very resilient in error-prone wireless communication environments. Search algorithms for two classical location-based queries, window queries and kNN queries, based on DSI are presented. Performance evaluation of DSI shows …


A Semi-Supervised Active Learning Framework For Image Retrieval, Steven Hoi, Michael R. Lyu Jun 2005

A Semi-Supervised Active Learning Framework For Image Retrieval, Steven Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Although recent studies have shown that unlabeled data are beneficial to boosting the image retrieval performance, very few approaches for image retrieval can learn with labeled and unlabeled data effectively. This paper proposes a novel semi-supervised active learning framework comprising a fusion of semi-supervised learning and support vector machines. We provide theoretical analysis of the active learning framework and present a simple yet effective active learning algorithm for image retrieval. Experiments are conducted on real-world color images to compare with traditional methods. The promising experimental results show that our proposed scheme significantly outperforms the previous approaches.


Minimum Energy Reliable Paths Using Unreliable Wireless Links, Qunfeng Dong, Suman Banerjee, Micah Adler, Archan Misra May 2005

Minimum Energy Reliable Paths Using Unreliable Wireless Links, Qunfeng Dong, Suman Banerjee, Micah Adler, Archan Misra

Research Collection School Of Computing and Information Systems

We address the problem of energy-efficient reliable wireless communication in the presence of unreliable or lossy wireless link layers in multi-hop wireless networks. Prior work [1] has provided an optimal energy efficient solution to this problem for the case where link layers implement perfect reliability. However, a more common scenario --- a link layer that is not perfectly reliable, was left as an open problem. In this paper we first present two centralized algorithms, BAMER and GAMER, that optimally solve the minimum energy reliable communication problem in presence of unreliable links. Subsequently we present a distributed algorithm, DAMER, that approximates …


Live Data Views: Programming Pervasive Applications That Use “Timely” And “Dynamic” Data, Jay Black, Paul Castro, Archan Misra, Jerome White May 2005

Live Data Views: Programming Pervasive Applications That Use “Timely” And “Dynamic” Data, Jay Black, Paul Castro, Archan Misra, Jerome White

Research Collection School Of Computing and Information Systems

In the absence of generic programming abstractions for dynamic data in most enterprise programming environments, individual applications treat data streams as a special case requiring custom programming. With the growing number of live data sources such as RSS feeds, messaging and presence servers, multimedia streams, and sensor data. a general-purpose client-server programming model is needed to easily incorporate live data into applications. In this paper, we present Live Data Views, a programming abstraction that represents live data as a time-windowed view over a set of data streams. Live Data Views allow applications to create and retrieve stateful abstractions of dynamic …


Synthesizing E-Government Stage Models – A Meta-Synthesis Based On Meta-Ethnography Approach, Keng Siau, Y. Long May 2005

Synthesizing E-Government Stage Models – A Meta-Synthesis Based On Meta-Ethnography Approach, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

The growing interest in e-government raises the question of stages in e-government development. A few stage models for e-government have been proposed. Without a common e-government stage model, different research in e-government may be based on different stage models. This presents a difficulty in comparing and understanding different research results. In this research, we synthesize the existing e-government stage models so that there is a common frame of reference for researchers and practitioners in the area.


Dynamically-Optimized Context In Recommender Systems, Ghim-Eng Yap, Ah-Hwee Tan, Hwee-Hwa Pang May 2005

Dynamically-Optimized Context In Recommender Systems, Ghim-Eng Yap, Ah-Hwee Tan, Hwee-Hwa Pang

Research Collection School Of Computing and Information Systems

Traditional approaches to recommender systems have not taken into account situational information when making recommendations, and this seriously limits the relevance of the results. This paper advocates context-awareness as a promising approach to enhance the performance of recommenders, and introduces a mechanism to realize this approach. We present a framework that separates the contextual concerns from the actual recommendation module, so that contexts can be readily shared across applications. More importantly, we devise a learning algorithm to dynamically identify the optimal set of contexts for a specific recommendation task and user. An extensive series of experiments has validated that our …


Secure Human Communications Based On Biometrics Signals, Yongdong Wu, Feng Bao, Robert H. Deng May 2005

Secure Human Communications Based On Biometrics Signals, Yongdong Wu, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

User authentication is the first and probably the most challenging step in achieving secure person-to-person communications. Most of the existing authentication schemes require communicating parties either share a secret/password or know each other's public key. In this paper we suggest a novel user authentication scheme that is easy to use and overcomes the requirements of sharing password or public keys. Our scheme allows two human users to perform mutual authentication and have secure communications over an open channel by exchanging biometrics signals (e. g., voice or video signals). In addition to user authentication, our scheme establishes a secret session key …


Tosa: A Near-Optimal Scheduling Algorithm For Multi-Channel Data Broadcast, Baihua Zheng, Xia Xu, Xing Jin, Dik Lun Lee May 2005

Tosa: A Near-Optimal Scheduling Algorithm For Multi-Channel Data Broadcast, Baihua Zheng, Xia Xu, Xing Jin, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Wireless broadcast is very suitable for delivering information to a large user population. In this paper, we concentrate on data allocation methods for multiple broadcast channels. To the best of our knowledge, this is the first allocation model that takes into the consideration of items' access frequencies, items' lengths. and bandwidth of different channels. We first derive the optimal average expected delay for multiple channels for the general case where data access frequencies, data sizes, and channel bandwidths can all be non-uniform. Second, we develop TOSA, a multi-channel allocation method that does not assume a uniform broadcast schedule for data …


Event-Driven Document Selection For Terrorism, Zhen Sun, Ee Peng Lim, Kuiyu Chang, Teng-Kwee Ong, Rohan Kumar Gunaratna May 2005

Event-Driven Document Selection For Terrorism, Zhen Sun, Ee Peng Lim, Kuiyu Chang, Teng-Kwee Ong, Rohan Kumar Gunaratna

Research Collection School Of Computing and Information Systems

In this paper, we examine the task of extracting information about terrorism related events hidden in a large document collection. The task assumes that a terrorism related event can be described by a set of entity and relation instances. To reduce the amount of time and efforts in extracting these event related instances, one should ideally perform the task on the relevant documents only. We have therefore proposed some document selection strategies based on information extraction (IE) patterns. Each strategy attempts to select one document at a time such that the gain of event related instance information is maximized. Our …


Mining Mobile Group Patterns: A Trajectory-Based Approach, San-Yih Hwang, Ying-Han Liu, Jeng-Kuen Chiu, Ee Peng Lim May 2005

Mining Mobile Group Patterns: A Trajectory-Based Approach, San-Yih Hwang, Ying-Han Liu, Jeng-Kuen Chiu, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In this paper, we present a group pattern mining approach to derive the grouping information of mobile device users based on a trajectory model. Group patterns of users are determined by distance threshold and minimum time duration. A trajectory model of user movement is adopted to save storage space and to cope with untracked or disconnected location data. To discover group patterns, we propose ATGP algorithm and TVG-growth that are derived from the Apriori and VG-growth algorithms respectively.


Information Dissemination Via Wireless Broadcast, Baihua Zheng, Dik Lun Lee May 2005

Information Dissemination Via Wireless Broadcast, Baihua Zheng, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Unrestricted mobility adds a new dimension to data access methodology--- one that must be addressed before true ubiquity can be realized.