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Low Latency Multimedia Broadcast In Multi-Rate Wireless Meshes, Chun-Tong Chou, Archan Misra
Low Latency Multimedia Broadcast In Multi-Rate Wireless Meshes, Chun-Tong Chou, Archan Misra
Research Collection School Of Computing and Information Systems
In a multi-rate wireless network, a node can dynamically adjust its link transmission rate by switching between different modulation schemes. For the current IEEE802.11a/b/g standards, this rate adjustment is limited to unicast traffic only while multicast and broadcast traffic is always transmitted at the lowest possible rate. In this paper, we consider a novel type of multi-rate mesh networks where a node can dynamically adjust its link layer multicast rates to its neighbours. In particular, we consider the problem of realising low latency network-wide broadcast in this type of multi-rate wireless meshes. We will first show that the multi-rate broadcast …
Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay
Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay
Research Collection School Of Computing and Information Systems
We present further steps in our research into visual languages for animation. Animation is a rich mode of communication that is currently accessible to few, because animation systems are complex. Some systems try to make animation simple but put severe limits on users’ creative expression. Our field studies are demonstrating that would-be animators need to express animation in a wide variety of ways. We are developing a taxonomy of forms of expression for animation that will help the designers of visual languages for animation to determine which expressive forms to support. Our end goal is to build animation sketching systems …
Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu
Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu
Research Collection School Of Computing and Information Systems
The Open Constraint Optimization Problem (OCOP) refers to the COP where constraints and variable domains can change over time and agents' opinions have to be sought over a distributed network to form a solution. The openness of the problem has caused conventional approaches to COP such as branch-and-bound to fail to find optimal solutions. OCOP is a new problem and the approach to find an optimal solution (minimum total cost) introduced in [1] is based on an unrealistic assumption that agents are willing to report their options in nondecreasing order of cost. In this paper, we study a generalized OCOP …
New Efficient Mds Array Codes For Raid Part I: Reed-Solomon-Like Codes For Tolerating Three Disk Failures, Gui-Liang Feng, Robert H. Deng, Feng Bao, Jia-Chen Shen
New Efficient Mds Array Codes For Raid Part I: Reed-Solomon-Like Codes For Tolerating Three Disk Failures, Gui-Liang Feng, Robert H. Deng, Feng Bao, Jia-Chen Shen
Research Collection School Of Computing and Information Systems
This paper presents a class of binary maximum distance separable (MDS) array codes for tolerating disk failures in redundant arrays of inexpensive disks (RAID) architecture based on circular permutation matrices. The size of the information part is m×n, the size of the parity-check part is m×3, and the minimum distance is 4, where n is the number of information disks, the number of parity-check disks is 3, and (m+1) is a prime integer. In practical applications, m can be very large and n is from 20 to 50. The code rate is R=n/(n+3). These codes can be used for tolerating …
Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo
Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo
Research Collection School Of Computing and Information Systems
In a rapidly changing environment, the behavior and decision-making power of agents may have to be adaptive with respect to a fluctuating autonomy. In this paper, a centralized fuzzy approach is proposed to sense changes in environmental conditions and translate them to changes in agent autonomy. A distributed coalition formation scheme is then applied to allow agents in the new autonomy to renegotiate to establish schedule consistency. The proposed framework is applied to a real-time logistics control of a military hazardous material storage facility under peace-to-war transition.
On Organizing And Accessing Geospatial And Georeferenced Web Resources Using The G-Portal System, Zehua Liu, Ee Peng Lim, Yin-Leng Theng, Dion Hoe-Lian Goh, Wee-Keong Ng
On Organizing And Accessing Geospatial And Georeferenced Web Resources Using The G-Portal System, Zehua Liu, Ee Peng Lim, Yin-Leng Theng, Dion Hoe-Lian Goh, Wee-Keong Ng
Research Collection School Of Computing and Information Systems
In order to organise and manage geospatial and georeferenced information on the Web making them convenient for searching and browsing, a digital portal known as G-Portal has been designed and implemented. Compared to other digital libraries, G-Portal is unique for several of its features. It maintains metadata resources in XML with flexible resource schemas. Logical groupings of metadata resources as projects and layers are possible to allow the entire metadata collection to be partitioned differently for users with different information needs. These metadata resources can be displayed in both the classification-based and map-based interfaces provided by G-Portal. G-Portal further incorporates …
Impact On Open Source Software Performance: A View From Social Structure, Y. Long, Keng Siau
Impact On Open Source Software Performance: A View From Social Structure, Y. Long, Keng Siau
Research Collection School Of Computing and Information Systems
Open source software (OSS) has drawn increasing attention from both practitioners and researchers in recent years. However, few empirical studies have investigated the interaction process of OSS teams during OSS development. This research has two primary objectives. The first is to study the social structure of OSS teams. The second is to investigate the factors impacting the social structure of OSS teams as well as the effects of the social structure on OSS performance. Based on the social structure and social network theory, and group-related theories, this paper first presented a general research framework, then discussed research methodology, and finally …
Introduction: Human-Computer Interaction Studies In Management Information Systems, Fiona Fui-Hoon Nah, P. Zhang, S. Mccoy
Introduction: Human-Computer Interaction Studies In Management Information Systems, Fiona Fui-Hoon Nah, P. Zhang, S. Mccoy
Research Collection School Of Computing and Information Systems
Human-computer interaction (HCI) is a critical area of research and practice that spans several disciplines, including industrial engineering, management information systems (MIS), computer science, information science, psychology, sociology, and anthropology. HCI research within the MIS discipline has distinct features shaped by the evolution and current state of MIS. Originating as applied computer science in the 1970s, MIS gradually transformed into a more social science–oriented discipline (Baskerville & Myers, 2002). MIS is broadly defined as “the effective design, delivery, and use of information systems in organizations” (Keen, 1980, p. 14). The two distinguishing features of MIS compared to other "homes" of …
Information Search Patterns In E-Commerce Product Comparison Services, Fiona Fui-Hoon Nah, Hong-Hee Lee, Liqiang Chen
Information Search Patterns In E-Commerce Product Comparison Services, Fiona Fui-Hoon Nah, Hong-Hee Lee, Liqiang Chen
Research Collection School Of Computing and Information Systems
The presentation of product information is very important in e-commerce websites. In this research, we study how disposition styles can influence users‟ search patterns in product comparison services of e-commerce websites. Our results show that people are inclined to use feature information paths in vertical disposition style and product information paths in horizontal disposition style. The results also indicate that there are more feature paths than product paths in the earlier stage of product comparison, and more product paths than feature paths in the latter stage of product comparison. Based on Gensch‟s two-stage choice model and the results of our …
Privacy Issues In The Era Of Ubiquitous Commerce, Holtjona Galanxhi, Fiona Fui-Hoon Nah
Privacy Issues In The Era Of Ubiquitous Commerce, Holtjona Galanxhi, Fiona Fui-Hoon Nah
Research Collection School Of Computing and Information Systems
The vision of ubiquitous commerce (u-commerce) is realized through the convergence of electronic, mobile, television, voice and silent commerce applications. The ubiquity, universality, uniqueness, and unison of u-commerce will provide two principal benefits for individual users and companies: increased convenience as well as more personalized and customized services. However, u-commerce will also bring new issues such as a greater degree of privacy concerns that will impact individual users, companies, and the society at large. This paper proposes and elaborates on a conceptual framework for privacy in the u-commerce era. It combines Lessig’s macro-level perspective – the four-factor model of privacy …
Dispatching Vehicles In A Mega Container Terminal, Ebru K. Bish, Frank Y. Chen, Thin Yin Leong, Barry L. Nelson, Jonathan W. C. Ng, David Simchi-Levi
Dispatching Vehicles In A Mega Container Terminal, Ebru K. Bish, Frank Y. Chen, Thin Yin Leong, Barry L. Nelson, Jonathan W. C. Ng, David Simchi-Levi
Research Collection School Of Computing and Information Systems
We consider a container terminal discharging and uploading containers to and from ships. The discharged containers are stored at prespecified storage locations in the terminal yard. Containers are moved between the ship area and the yard using a fleet of vehicles, each of which can carry one container at a time. The problem is to dispatch vehicles to the containers so as to minimize the total time it takes to serve a ship, which is the total time it takes to discharge all containers from the ship and upload new containers onto the ship. We develop easily implementable heuristic algorithms …
Towards A Theoretical Framework Of Information Systems Development Success, Y. Long, Keng Siau, M. Ling
Towards A Theoretical Framework Of Information Systems Development Success, Y. Long, Keng Siau, M. Ling
Research Collection School Of Computing and Information Systems
Information systems development (ISD) is a complicated process involving interconnected resources, objects, and outcomes. The importance of ISD has attracted long-term interests from both researchers and practitioners. Based on the input-process-output model, this paper developed a conceptual framework of ISD success through a systematic literature review. The paper argues that ISD is a comprehensive and interactive process among individuals, teams, and organization. These factors impact ISD process, and further affect ISD success.
Web Browsing And Spyware Intrusion, S. Shukla, Fiona Fui-Hoon Nah
Web Browsing And Spyware Intrusion, S. Shukla, Fiona Fui-Hoon Nah
Research Collection School Of Computing and Information Systems
Spyware poses serious privacy and security issues to users of e-commerce and m-commerce [3, 5, 8]. Microsoft claims that half of all computer crashes reported by its customers were caused by spyware and its equivalents. Spyware is also responsible for about 12% of all technical support calls and accounts for the biggest category of customer complaints, according to Dell
Values Of Silent Commerce: A Study Using Value-Focused Thinking Approach, H. Sheng, Fiona Fui-Hoon Nah, Keng Siau
Values Of Silent Commerce: A Study Using Value-Focused Thinking Approach, H. Sheng, Fiona Fui-Hoon Nah, Keng Siau
Research Collection School Of Computing and Information Systems
Silent commerce is a special type of u-commerce that uses RFID and sensor technologies to make objects intelligent and interactive. The unique features available in silent commerce will provide benefits and added values to users. This study aims to uncover the values of silent commerce from the customers’ perspectives and understand what customers desire and expect from silent commerce. The scenario-based method was adopted to provide subjects with the necessary background information and knowledge about the emerging silent commerce phenomenon. The Value-Focused Thinking approach, which provides a systematic way to articulate and organize values, was used to identify the values …
Geogdl: A Web-Based Approach To Geography Examination, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng
Geogdl: A Web-Based Approach To Geography Examination, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng
Research Collection School Of Computing and Information Systems
The traditional educational approach with students as passive recipients has been the subject of criticism. A constructivist learner-centered approach towards education has been argued to produce greater internalization and application of knowledge compared to the traditional teacher-centered, transmission-oriented approach. Nevertheless, contemporary instructional design models argue for the use and integration of both approaches especially in complex learning tasks. This paper describes GeogDL, a Web-based application developed above a digital library of geographical resources for Singapore students preparing to take a national examination in geography. GeogDL is unique in that it not only provides an environment for active learning, it also …
Evaluation Of Time-Varying Availability In Multi-Echelon Inventory System With Combat Damage, Hoong Chuin Lau, Huawei Song
Evaluation Of Time-Varying Availability In Multi-Echelon Inventory System With Combat Damage, Hoong Chuin Lau, Huawei Song
Research Collection School Of Computing and Information Systems
The models for multi-echelon inventory systems in existing literatures predominantly address failures due to reliability in peacetime. In wartime or even peacetime operational scenarios, unexpected combat damage can cause a large number of systems to be heavily damaged, to the extent that they become irreparable. In this paper, we study a multi-echelon spare parts support system under combat damage, discuss the replenishment policy and propose an approximate method to evaluate the time-varying system performance operational availability considering the effect of passivation. Experiments show our model works well and efficiently against simulation.
End-Users’ Acceptance Of Enterprise Resource Planning Systems: An Investigation Using Grounded Theory Approach, Fiona Fui-Hoon Nah, Xin Tan, Monica Beethe
End-Users’ Acceptance Of Enterprise Resource Planning Systems: An Investigation Using Grounded Theory Approach, Fiona Fui-Hoon Nah, Xin Tan, Monica Beethe
Research Collection School Of Computing and Information Systems
The success of ERP implementation depends, to a large extent, on the intensity and nature of its use by end-users. Therefore, it is important to understand the phenomena underlying end-users’ acceptance of ERP systems. This study was conducted at a large institution that implemented an ERP system. It uses the grounded theory approach to inductively develop a model that highlights key factors influencing end-users’ acceptance of ERP systems.
Personalization Of Web Services: A Study On The Fit Between Web Tasks And Personalization Mechanisms, Fiona Fui-Hoon Nah, Keng Siau, Min Ling
Personalization Of Web Services: A Study On The Fit Between Web Tasks And Personalization Mechanisms, Fiona Fui-Hoon Nah, Keng Siau, Min Ling
Research Collection School Of Computing and Information Systems
Personalization is increasingly being considered an important ingredient of Web applications. In most cases, personalization techniques and mechanisms are used for tailoring information services to user needs. It is motivated by the recognition that a user has needs, and meeting them successfully is likely to lead to a satisfying relationship and re-use of the Web services offered. However, if the personalization mechanisms do not match the needs depicted by the tasks, it will decrease user satisfaction and performance. In this research, we use the cognitive fit theory to examine the fit between personalization mechanisms and Web tasks.
Privacy Issues In The Era Of Ubiquitous Commerce, Holtjona Galanxhi, Fiona Fui-Hoon Nah
Privacy Issues In The Era Of Ubiquitous Commerce, Holtjona Galanxhi, Fiona Fui-Hoon Nah
Research Collection School Of Computing and Information Systems
The vision of ubiquitous commerce (u‐commerce) is realized through the convergence of electronic, mobile, television, voice and silent commerce applications. The ubiquity, universality, uniqueness and unison of u‐commerce will provide two principal benefits for individual users and businesses: increased convenience as well as more personalized and customized services. However, u‐commerce will also bring emerging issues such as a greater degree of privacy concerns that will impact individual users, companies and society at large. This paper proposes and elaborates on a conceptual framework for privacy in the u‐commerce era. This framework is developed based on Lessig's macro‐level perspective and Adams' micro‐level …
Evaluation Criteria For Information Systems Development Methodologies, Keng Siau, Xin Tan
Evaluation Criteria For Information Systems Development Methodologies, Keng Siau, Xin Tan
Research Collection School Of Computing and Information Systems
The evaluation of information systems development methodologies is becoming increasingly important. The lack of a commonly acceptable set of criteria for evaluation, however, hinders aggregating knowledge from field studies. Our study attempts to fill the gap. To reduce the effects of subjectivity, we surveyed the opinions of a group (28) of experienced IS researchers. Fifty-one criteria were generated from the research participants. A systematic content analysis technique will be applied for grouping the unique criteria into general categories. Upon completion, our study can make both academic and practical contributions in evaluating ISD methodologies.
Toward Practical Measures Of Complexity In Real-Time Modeling Methods, J. Erickson, Keng Siau
Toward Practical Measures Of Complexity In Real-Time Modeling Methods, J. Erickson, Keng Siau
Research Collection School Of Computing and Information Systems
Systems development methods have become more complex, concurrently with many of today’s systems. UML has been criticized for its complexity. Using Rossi and Brinkkemper’s (1996) complexity metrics, Siau and Cao, (2001) completed a complexity analysis of UML and other modeling techniques, finding that UML is more complex than other techniques. Siau, Erickson and Lee (2002) proposed that Rossi and Brinkkemper’s metrics present the theoretical maximum complexity, as opposed to a practitioner-based complexity, that must be less than the theoretical maximum. Erickson and Siau (2004) proposed that a subset of UML (a kernel) composed of the most commonly used constructs, could …
An Investigation Into The Continued Use Of Unified Modeling Language (Uml) In Information Systems Development, Keng Siau, X. Tan
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
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 …
Medoid Queries In Large Spatial Databases, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou
Medoid Queries In Large Spatial Databases, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou
Research Collection School Of Computing and Information Systems
Assume that a franchise plans to open k branches in a city, so that the average distance from each residential block to the closest branch is minimized. This is an instance of the k-medoids problem, where residential blocks constitute the input dataset and the k branch locations correspond to the medoids. Since the problem is NP-hard, research has focused on approximate solutions. Despite an avalanche of methods for small and moderate size datasets, currently there exists no technique applicable to very large databases. In this paper, we provide efficient algorithms that utilize an existing data-partition index to achieve low CPU …
Constrained Shortest Path Computation, Manolis Terrovitis, Spiridon Bakiras, Dimitris Papadias, Kyriakos Mouratidis
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
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
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
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
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
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 …