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Research Collection School Of Computing and Information Systems

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Applying Scenario-Based Design And Claim Analysis To The Design Of A Digital Library Of Geography Examination Resources, Yin-Leng Theng, Dion Hoe-Lian Goh, Ee Peng Lim, Zehua Liu, Ming Yin, Natalie Lee-San Pang, Patricia Bao-Bao Wong Jan 2005

Applying Scenario-Based Design And Claim Analysis To The Design Of A Digital Library Of Geography Examination Resources, Yin-Leng Theng, Dion Hoe-Lian Goh, Ee Peng Lim, Zehua Liu, Ming Yin, Natalie Lee-San Pang, Patricia Bao-Bao Wong

Research Collection School Of Computing and Information Systems

This paper describes the application of Carroll’s scenario-based design and claims analysis as a means of refinement to the initial design of a digital library of geographical resources (GeogDL) to prepare Singapore students to take a national examination in geography. GeogDL is built on top of G-Portal, a digital library providing services over geospatial and georeferenced Web content. Beyond improving the initial design of GeogDL, a main contribution of the paper is making explicit the use of Carroll’s strong theory-based but undercapitalized scenario-based design and claims analysis that inspired recommendations for the refinement of GeogDL. The paper concludes with an …


A Multi-Agent Approach For Solving Optimization Problems Involving Expensive Resources, Hoong Chuin Lau, H. Wang Jan 2005

A Multi-Agent Approach For Solving Optimization Problems Involving Expensive Resources, Hoong Chuin Lau, H. Wang

Research Collection School Of Computing and Information Systems

In this paper, we propose a multi-agent approach for solving a class of optimization problems involving expensive resources, where monolithic local search schemes perform miserably. More specifically, we study the class of bin-packing problems. Under our proposed Fine-Grained Agent System scheme, rational agents work both collaboratively and selfishly based on local search and mimic physics-motivated systems. We apply our approach to a generalization of bin-packing - the Inventory Routing Problem with Time Windows - which is an important logistics problem, and demonstrate the efficiency and effectiveness of our approach.


Systems Analysis And Design: Should We Be Researching What We Teach?, A. Bajaj, D. Batra, A. Hevner, J. Parsons, Keng Siau Jan 2005

Systems Analysis And Design: Should We Be Researching What We Teach?, A. Bajaj, D. Batra, A. Hevner, J. Parsons, Keng Siau

Research Collection School Of Computing and Information Systems

A guiding premise of academic scholarship is that knowledge gained from first-hand research experience is disseminated to students via the classroom. However, that valuable connection is lost when professors are not researching what they teach. In this paper, we explore issues of mismatch between teaching and research in the Information Systems (IS) discipline. Specifically, while systems analysis and design (SA&D) is an integral topic in IS curricula, this topic is the research specialty of few IS professors. This situation is reflected by the low number of research publications in this area; particularly in the leading mainstream IS journals. We characterize …


Robust Temporal Constraint Networks, Hoong Chuin Lau, Thomas Ou, Melvyn Sim Jan 2005

Robust Temporal Constraint Networks, Hoong Chuin Lau, Thomas Ou, Melvyn Sim

Research Collection School Of Computing and Information Systems

In this paper, we propose the Robust Temporal Constraint Network (RTCN) model for simple temporal constraint networks where activity durations are bounded by random variables. The problem is to determine whether such temporal network can be executed with failure probability less than a given 0 ≤ E ≤ 1 for each possible instantiation of the random variables, and if so. how one might find a feasible schedule with each given instantiation. The advantage of our model is that one can vary the value of ∊ to control the level of conservativeness of the solution. We present a computationally tractable and …


Exploring Bit-Difference For Approximate Knn Search In High-Dimensional Databases, Bin Cui, Heng Tao Shen, Jialie Shen, Kian-Lee Tan Jan 2005

Exploring Bit-Difference For Approximate Knn Search In High-Dimensional Databases, Bin Cui, Heng Tao Shen, Jialie Shen, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

In this paper, we develop a novel index structure to support effcient approximate k-nearest neighbor (KNN) query in high-dimensional databases. In high-dimensional spaces, the computational cost of the distance (e.g., Euclidean distance) between two points contributes a dominant portion of the overall query response time for memory processing. To reduce the distance computation, we first propose a structure (BID) using BIt-Difference to answer approximate KNN query. The BID employs one bit to represent each feature vector of point and the number of bit-difference is used to prune the further points. To facilitate real dataset which is typically skewed, we enhance …


Security Of An Ill-Posed Operator Based Scheme For Image Authentication, Yongdong Wu, Robert H. Deng Jan 2005

Security Of An Ill-Posed Operator Based Scheme For Image Authentication, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

This letter analyzes the security of an image authentication scheme which exploits the instability of an ill-posed operator. Since the ill-posed operator produces only a limited number of authentic images regardless of the number of watermarks, an attacker can impersonate an image owner to generate authentic images at a high probability. Our experiments demonstrate that our attack is both practical and effective.


Justilm: Few-Shot Justification Generation For Explainable Fact-Checking Of Real-World Claims, Fengzhu Zeng, Wei Gao Dec 2004

Justilm: Few-Shot Justification Generation For Explainable Fact-Checking Of Real-World Claims, Fengzhu Zeng, Wei Gao

Research Collection School Of Computing and Information Systems

Justification is an explanation that supports the verdict assigned to a claim in fact-checking. However, the task of justification generation is previously oversimplified as summarization of fact-check article authored by professional checkers. In this work, we propose a realistic approach to generate justification based on retrieved evidence. We present a new benchmark dataset called ExClaim for Explainable Claim verification, and introduce JustiLM, a novel few-shot retrieval-augmented language model to learn justification generation by leveraging fact-check articles as auxiliary resource during training. Our results show that JustiLM outperforms in-context learning (ICL)-enabled LMs including Flan-T5 and Llama2, and the retrieval-augmented model Atlas …


Method For Identifying Individuals, Manoj Thulasidas Dec 2004

Method For Identifying Individuals, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A method and system for identifying a subject comprises obtaining a digitised recording of an electrocardiogram measurement of the subject to be identified, the digitised recording being a cyclic waveform having a peak amplitude. The digitised recording is normalised to reduce variations due to physiological effects, and the normalised recording is processed to determine a feature vector in the frequency domain. The distance between the determined feature vector and a predetermined feature vector is measured to identify the subject.


Supporting Field Study With Personalized Project Spaces In A Geographical Digital Library, Ee Peng Lim, Aixin Sun, Zehua Liu, John Hedberg, Chew-Hung Chang, Tiong-Sa Teh, Dion Hoe-Lian Goh, Yin-Leng Theng Dec 2004

Supporting Field Study With Personalized Project Spaces In A Geographical Digital Library, Ee Peng Lim, Aixin Sun, Zehua Liu, John Hedberg, Chew-Hung Chang, Tiong-Sa Teh, Dion Hoe-Lian Goh, Yin-Leng Theng

Research Collection School Of Computing and Information Systems

Digital libraries have been rather successful in supporting learning activities by providing learners with access to information and knowledge. However, this level of support is passive to learners and interactive and collaborative learning cannot be easily achieved. In this paper, we study how digital libraries could be extended to serve a more active role in collaborative learning activities. We focus on developing new services to support a common type of learning activity, field study, in a geospatial context. We propose the concept of personal project space that allows individuals to work in their personalized environment with a mix of private …


Factors Impacting E-Government Development, Keng Siau, Y. Long Dec 2004

Factors Impacting E-Government Development, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

E-government is a way for governments to use new technologies such as the Internet to provide citizens with more convenient access to government information and services, to improve the quality of services, and to provide greater opportunities for citizens to participate in democratic institutions and processes. This research investigates factors impacting e-government development. Based on the growth theory and human capital theory from the economics literature, we hypothesize that information and computer technology, and human development are two factors impacting e-government development. The hypotheses were empirically tested using secondary data from the United Nations and the United Nations Development Programme. …


High Performance P300 Speller For Brain-Computer Interface, Cuntai Guan, Manoj Thulasidas, Jiankang Wu Dec 2004

High Performance P300 Speller For Brain-Computer Interface, Cuntai Guan, Manoj Thulasidas, Jiankang Wu

Research Collection School Of Computing and Information Systems

P300 speller is a communication tool with which one can input texts or commands to a computer by thought. The amplitude of the P300 evoked potential is inversely proportional to the probability of infrequent or task-related stimulus. In existing P300 spellers, rows and columns of a matrix are intensified successively and randomly, resulting in a stimulus frequency of 1/N (N is the number of rows or columns of the matrix). We propose a new paradigm to display each single character randomly and individually (therefore reducing the stimulus frequency to 1/(N*N)). On-line experiments showed that this new speller significantly improved the …


Theoretical And Practical Complexity Of Unified Modeling Language: Delphi Study And Metrics Analyses, J. Erickson, Keng Siau Dec 2004

Theoretical And Practical Complexity Of Unified Modeling Language: Delphi Study And Metrics Analyses, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

Systems have become increasingly complex, and as a result development methods have become more complex as well. The unified modeling language (UML) has been criticized for the often cited and sometimes over- whelming complexity it presents to its users, and those seeking to learn to use it. Using Rossi and Brinkkemper’s (1996) complexity metrics, Siau and Cao (2001) completed a complexity analysis of UML and 36 other modeling techniques, finding that UML is indeed more complex than other techniques. Siau, Erickson and Lee (2002) proposed that Rossi and Brinkkemper’s metrics present the theoretical maximum complexity, known as theoretical complexity. This …


Vertical Sensitivity For The Information Security Health Rating Of Enterprises, Arcot Desai Narasimhalu, Nagarajan Dayasindhu, Raghavan Subramanian Dec 2004

Vertical Sensitivity For The Information Security Health Rating Of Enterprises, Arcot Desai Narasimhalu, Nagarajan Dayasindhu, Raghavan Subramanian

Research Collection School Of Computing and Information Systems

INFOSeMM Maturity model was developed jointly by SMU and Infosys. It is recognized that different industry verticals will have different levels of recommended maturity levels. This paper articulates the need for developing the industry vertical benchmarks.


The Value Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah Dec 2004

The Value Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

This research studies the values of m-commerce using a qualitative means-ends approach, called Value-Focused Thinking. The conceptual foundation for this research is the Work System Framework. By interviewing both current and potential m-commerce users, we captured the values of m-commerce and develop a means-ends objective network to illustrate the relationships among these values. As one of the first empirical research to assess the values of m-commerce, this research contributes to an increased understanding of mcommerce. The means-ends objective network also serves as a theoretical foundation for future research in mcommerce. For practitioners, our findings highlight the concerns and issues of …


U-Commerce: Emerging Trends And Research Issues, H. Galanxhi-Janaqi, Fiona Fui-Hoon Nah Dec 2004

U-Commerce: Emerging Trends And Research Issues, H. Galanxhi-Janaqi, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

Ubiquitous commerce or u-commerce is the combination of traditional e-commerce and wireless, television, voice and silent commerce. U-commerce implies ubiquity, universality, uniqueness and unison. It is not a replacement for other types of commerce, but an extension of them. While bringing many benefits, there are challenges and impediments to overcome. Research is needed to assess the value of u-commerce and to address its related issues and challenges. Questions that need to be addressed are: What is the value of u-commerce? What are the ways to maximize the benefits and value of u-commerce? Is it the right technology and what directions …


Values Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah Dec 2004

Values Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

This research studies the values of m-commerce using a qualitative means-ends approach, called Value-Focused Thinking. The conceptual foundation for this research is the Work System Framework. By interviewing both current and potential m-commerce users, we captured the values of m-commerce and develop a means-ends objective network to illustrate the relationships among these values. As one of the first empirical research to assess the values of m-commerce, this research contributes to an increased understanding of m-commerce. The means-ends objective network also serves as a theoretical foundation for future research in m-commerce. For practitioners, our findings highlight the concerns and issues of …


Design Lessons On Access Features In Paper, Yin-Leng Theng, Dion Hoe-Lian Goh, Ming Yin, Eng-Kai Suen, Ee Peng Lim Dec 2004

Design Lessons On Access Features In Paper, Yin-Leng Theng, Dion Hoe-Lian Goh, Ming Yin, Eng-Kai Suen, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Using Nielsen's Heuristic Evaluation, this paper reports a user study with six usability-trained subjects to evaluate PAPER's access features in assisting users to retrieve information efficiently, part of an on-going design partnership with stakeholders and designers/developers. PAPER (Personalised Adaptive Pathways for Exam Resources) is an improved version evolving from an earlier implementation of GeogDL built upon G-Portal, a geospatial digital library infrastructure. After two initial evaluations with student and teacher design partners, PAPER has evolved into a system containing a new bundle of personalized, interactive services with four modules: mock exam; personal coach (practice and review); trend analysis and performance …


On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim Dec 2004

On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim

Research Collection School Of Computing and Information Systems

There have been some achievements in steganalysis recently. Many people have been making strides in steganalysis. They have approached steganalysis from different angles; from information theory to complexity theory. Anderson gave a possibility that there is a provable secure steganographic system, but there had not been complexity theoretical approaches for years. In 2002, Katzenbeisser and Petitcolas defined the conditional security of steganography and gave a possibility for a practical, provable secure steganography for the first time, and Hopper et al. introduced a provable secure steganographic algorithm in the sense of complexity theory. Chang et al. also tried to define the …


Automatic Model Structuring From Text Using Biomedical Ontology, Joshi R., Li X., Ramachandaran S., Tze-Yun Leong Dec 2004

Automatic Model Structuring From Text Using Biomedical Ontology, Joshi R., Li X., Ramachandaran S., Tze-Yun Leong

Research Collection School Of Computing and Information Systems

Bayesian Networks and Influence Diagrams are effective methods for structuring clinical problems. Constructing a relevant structure without the numerical probabilities in itself is a challenging task. In addition, due to the rapid rate of innovations and new findings in the biomedical domain, constructing a relevant graphical model becomes even more challenging. Building a model structure from text with minimum intervention from domain experts and minimum training examples has always been a challenge for the researchers. In the biomedical domain, numerous advances have been made which may make this dream a possibility now. We are currently trying to build a general …


On Semantic Caching And Query Scheduling For Mobile Nearest-Neighbor Search, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee Nov 2004

On Semantic Caching And Query Scheduling For Mobile Nearest-Neighbor Search, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Location-based services have received increasing attention in recent years. In this paper, we address the performance issues of mobile nearest-neighbor search, in which the mobile user issues a query to retrieve stationary service objects nearest to him/her. An index based on Voronoi Diagram is used in the server to support such a search, while a semantic cache is proposed to enhance the access efficiency of the service. Cache replacement policies tailored for the proposed semantic cache are examined. Moreover, several query scheduling policies are proposed to address the inter-cell roaming issues in multi-cell environments. Simulations are conducted to evaluate the …


Accommodating Instance Heterogeneities In Database Integration, Ee Peng Lim, Roger Hsiang-Li Chiang Nov 2004

Accommodating Instance Heterogeneities In Database Integration, Ee Peng Lim, Roger Hsiang-Li Chiang

Research Collection School Of Computing and Information Systems

A complete data integration solution can be viewed as an iterative process that consists of three phases, namely analysis, derivation and evolution. The entire process is similar to a software development process with the target application being the derivation rules for the integrated databases. In many cases, data integration requires several iterations of refining the local-to-global database mapping rules before a stable set of rules can be obtained. In particular, the mapping rules, as well as the data model and query model for the integrated databases have to cope with poor data quality in local databases, ongoing local database updates …


Spatial Queries In Wireless Broadcast Systems, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee Nov 2004

Spatial Queries In Wireless Broadcast Systems, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Owing to the advent of wireless networking and personal digital devices, information systems in the era of mobile computing are expected to be able to handle a tremendous amount of traffic and service requests from the users. Wireless data broadcast, thanks to its high scalability, is particularly suitable for meeting such a challenge. Indexing techniques have been developed for wireless data broadcast systems in order to conserve the scarce power resources in mobile clients. However, most of the previous studies do not take into account the impact of location information of users. In this paper, we address the issues of …


The D-Tree: An Index Structure For Planar Point Queries Location-Based Wireless Services, Jianliang Xu, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee Nov 2004

The D-Tree: An Index Structure For Planar Point Queries Location-Based Wireless Services, Jianliang Xu, Baihua Zheng, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Location-based services (LBSs), considered as a killer application in the wireless data market, provide information based on locations specified in the queries. In this paper, we examine the indexing issue for querying location-dependent data in wireless LBSs; in particular, we focus on an important class of queries, planar point queries. To address the issues of responsiveness, energy consumption, and bandwidth contention in wireless communications, an index has to minimize the search time and maintain a small storage overhead. It is shown that the traditional point-location algorithms and spatial index structures fail to achieve either objective or both. This paper proposes …


Corrective Maintenance Optimization In An Air Force, Hoong Chuin Lau, K. Y. Neo, W. C. Wan Nov 2004

Corrective Maintenance Optimization In An Air Force, Hoong Chuin Lau, K. Y. Neo, W. C. Wan

Research Collection School Of Computing and Information Systems

Successful military mission planning and execution depend critically on equipment serviceability and resupply. Due to the stochastic nature of demands, the forecast of optimal spares and resources needed to guarantee the level of serviceability is a complex problem, especially in a multi-echelon setting. In this paper, we propose a decision-support concept and software tool known as Corrective Maintenance Optimizer (CMO) that helps to optimize system availability, through proper allocation of spare parts, both strategically and operationally.


Job Scheduling With Unfixed Availability Constraints, Hoong Chuin Lau, C. Zhang Nov 2004

Job Scheduling With Unfixed Availability Constraints, Hoong Chuin Lau, C. Zhang

Research Collection School Of Computing and Information Systems

Standard scheduling theory assumes that all machines are continuously available throughout the planning horizon. In many manufacturing and service management situations however, machines need to be maintained periodically to prevent malfunctions. During the maintenance period, a machine is not available for processing jobs. Hence, a more realistic scheduling model should take into account machine maintenance activities. In this paper, we study the problem of job scheduling with unfixed availability constraints on a single machine. We first propose a preliminary classification for the scheduling problem with unfixed availability constraints based on maintenance constraints, job characteristics and objective function. We divide our …


Logistics Network Design With Differentiated Delivery Lead Time: A Chemical Industry Case Study, Michelle Lee Fong Cheong, Rohit Bhatnagar, Stephen C. Graves Nov 2004

Logistics Network Design With Differentiated Delivery Lead Time: A Chemical Industry Case Study, Michelle Lee Fong Cheong, Rohit Bhatnagar, Stephen C. Graves

Research Collection School Of Computing and Information Systems

Most logistics network design models assume exogenous customer demand that is independent of the service time or level. This paper examines the benefits of segmenting demand according to lead-time sensitivity of customers. To capture lead-time sensitivity in the network design model, we use a facility grouping method to ensure that the different demand classes are satisfied on time. In addition, we perform a series of computational experiments to develop a set of managerial insights for the network design decision making process.


Two-Echelon Repairable Item Inventory System With Limited Repair Capacity Under Nonstationary Demands, Hoong Chuin Lau, Huawei Song Nov 2004

Two-Echelon Repairable Item Inventory System With Limited Repair Capacity Under Nonstationary Demands, Hoong Chuin Lau, Huawei Song

Research Collection School Of Computing and Information Systems

We study a repairable item inventory system under limited repair capacity and nonstationary Poisson demands, motivated by corrective maintenance of military equipment. Our goal is to minimize the cost of both spare and repair resource allocation. We propose an efficient analytical model that combines optimization modeling and queuing theory.


Finding Constrained Frequent Episodes Using Minimal Occurrences, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan Nov 2004

Finding Constrained Frequent Episodes Using Minimal Occurrences, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

Recurrent combinations of events within an event sequence, known as episodes, often reveal useful information. Most of the proposed episode mining algorithms adopt an apriori-like approach that generates candidates and then calculates their support levels. Obviously, such an approach is computationally expensive. Moreover, those algorithms are capable of handling only a limited range of constraints. In this paper, we introduce two mining algorithms - episode prefix tree (EPT) and position pairs set (PPS) - based on a prefix-growth approach to overcome the above limitations. Both algorithms push constraints systematically into the mining process. Performance study shows that the proposed algorithms …


A Periodic-Review Inventory Model With Application To The Continuous-Review Obsolescence Problem, Yuyue Song, Hoong Chuin Lau Nov 2004

A Periodic-Review Inventory Model With Application To The Continuous-Review Obsolescence Problem, Yuyue Song, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In this paper we consider a stochastic-demand periodic-review inventory model with sudden obsolescence. We characterize the structure of the optimal policy and propose a dynamic programming algorithm for computing its parameters. We then utilize this algorithm to approximate the solution to the continuous-review sudden obsolescence problem with general obsolescence distribution. We prove convergence of our approximation scheme, and demonstrate it numerically against known closed-form solutions of special cases.


Anonymous Secure Routing In Mobile Ad-Hoc Networks, Bo Zhu, Zhiguo Wan, Mohan S. Kankanhalli, Feng Bao, Robert H. Deng Nov 2004

Anonymous Secure Routing In Mobile Ad-Hoc Networks, Bo Zhu, Zhiguo Wan, Mohan S. Kankanhalli, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Although there are a large number of papers on secure routing in mobile ad-hoc networks, only a few consider the anonymity issue. In this paper, we define more strict requirements on the anonymity and security properties of the routing protocol, and notice that previous research works only provide Weak Location Privacy and Route Anonymity, and are vulnerable to specific attacks. Therefore, we propose the Anonymous Secure Routing (ASR) protocol that can provide additional properties on anonymity, i.e. Identity Anonymity and Strong Location Privacy, and at the same time ensure the security of discovered routes against various passive and active attacks. …