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Research Collection School Of Computing and Information Systems

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Transport Logistics Planning With Service-Level Constraints, Hoong Chuin Lau, K. M. Ng, Xintao Wu Jul 2004

Transport Logistics Planning With Service-Level Constraints, Hoong Chuin Lau, K. M. Ng, Xintao Wu

Research Collection School Of Computing and Information Systems

In this paper, we study a logistics problem arising in military transport planning. A military organization operates a large fleet of vehicles in a depot to serve the requests of various operational units. Each request has a fixed start and end time, and is served by a prescribed number of vehicles. We address the following two problems: (1) how many vehicles are at least needed to meet a given service level of requests; and (2) suppose we allow each request to shift its start time by a constant duration, call all the requests be met? A Niche genetic algorithm, together …

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A Support-Ordered Trie For Fast Frequent Itemset Discovery, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng Jul 2004

A Support-Ordered Trie For Fast Frequent Itemset Discovery, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

The importance of data mining is apparent with the advent of powerful data collection and storage tools; raw data is so abundant that manual analysis is no longer possible. Unfortunately, data mining problems are difficult to solve and this prompted the introduction of several novel data structures to improve mining efficiency. Here, we critically examine existing preprocessing data structures used in association rule mining for enhancing performance in an attempt to understand their strengths and weaknesses. Our analyses culminate in a practical structure called the SOTrielT (support-ordered trie itemset) and two synergistic algorithms to accompany it for the fast discovery …

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Infosemm: Infosys It Security Maturity Model: A Report, Arcot Desai Narasimhalu, N. Dayasindhu, Raghavan Subramanian Jul 2004

Infosemm: Infosys It Security Maturity Model: A Report, Arcot Desai Narasimhalu, N. Dayasindhu, Raghavan Subramanian

Research Collection School Of Computing and Information Systems

Businesses are faced with a continuing battle related to cyber security related issues ranging from cyber attacks all the way to cyber (information) war. These issues affect result in information, system, reputation, and revenue related risks. These risks arise because of vulnerabilities introduced in three major parts of the enterprise – infrastructure, intelligence and practices. This report provides a rating system for representing the security health of enterprises.

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Taking Dcop To The Real World: Efficient Complete Solutions For Distributed Event Scheduling, Rajiv Maheswaran, Milind Tambe, Emma Bowring, Jonathan Pearce, Pradeep Varakantham Jul 2004

Taking Dcop To The Real World: Efficient Complete Solutions For Distributed Event Scheduling, Rajiv Maheswaran, Milind Tambe, Emma Bowring, Jonathan Pearce, Pradeep Varakantham

Research Collection School Of Computing and Information Systems

Distributed Constraint Optimization (DCOP) is an elegant formalism relevant to many areas in multiagent systems, yet complete algorithms have not been pursued for real world applications due to perceived complexity. To capably capture a rich class of complex problem domains, we introduce the Distributed Multi-Event Scheduling (DiMES) framework and design congruent DCOP formulations with binary constraints which are proven to yield the optimal solution. To approach real-world efficiency requirements, we obtain immense speedups by improving communication structure and precomputing best case bounds. Heuristics for generating better communication structures and calculating bound in a distributed manner are provided and tested on …

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Biased Support Vector Machine For Relevance Feedback In Image Retrieval, Steven Hoi, Chi-Hang Chan, Kaizhu Huang, Michael R. Lyu, Irwin King Jul 2004

Biased Support Vector Machine For Relevance Feedback In Image Retrieval, Steven Hoi, Chi-Hang Chan, Kaizhu Huang, Michael R. Lyu, Irwin King

Research Collection School Of Computing and Information Systems

Recently, support vector machines (SVMs) have been engaged on relevance feedback tasks in content-based image retrieval. Typical approaches by SVMs treat the relevance feedback as a strict binary classification problem. However, these approaches do not consider an important issue of relevance feedback, i.e. the unbalanced dataset problem, in which the negative instances largely outnumber the positive instances. For solving this problem, we propose a novel technique to formulate the relevance feedback based on a modified SVM called biased support vector machine (Biased SVM or BSVM). Mathematical formulation and explanations are provided for showing the advantages. Experiments are conducted to evaluate …

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An Interactive Learning Environment For A Dynamic Educational Digital Library, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng, Eng-Kai Suen Jul 2004

An Interactive Learning Environment For A Dynamic Educational Digital Library, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng, Eng-Kai Suen

Research Collection School Of Computing and Information Systems

GeogDL is a digital library of geography examination resources designed to assist students in preparing for a national geography examination in Singapore. We describe an interactive learning environment built into GeogDL that consists of four major components. The practice and review module allows students to attempt individual examination questions, the mock exam provides a simulation of the actual geography examination, the trends analysis tool provides an overview of the types of questions asked in previous examinations, while the contributions module allows students and teachers to create and share knowledge within the digital library.

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Notes On Equilibria In Symmetric Games, Shih-Fen Cheng, Daniel M. Reeves, Yevgeniy Vorobeychik, Michael P. Wellman Jul 2004

Notes On Equilibria In Symmetric Games, Shih-Fen Cheng, Daniel M. Reeves, Yevgeniy Vorobeychik, Michael P. Wellman

Research Collection School Of Computing and Information Systems

In a symmetric game, every player is identical with respect to the game rules. We show that a symmetric 2strategy game must have a pure-strategy Nash equilibrium. We also discuss Nash’s original paper and its generalized notion of symmetry in games. As a special case of Nash’s theorem, any finite symmetric game has a symmetric Nash equilibrium. Furthermore, symmetric infinite games with compact, convex strategy spaces and continuous, quasiconcave utility functions have symmetric pure-strategy Nash equilibria. Finally, we discuss how to exploit symmetry for more efficient methods of finding Nash equilibria.

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An Empirical Investigation On End-Users’ Acceptance Of Enterprise Systems, Fiona Fui-Hoon Nah, Xin Tan, Soon Hing Teh Jul 2004

An Empirical Investigation On End-Users’ Acceptance Of Enterprise Systems, Fiona Fui-Hoon Nah, Xin Tan, Soon Hing Teh

Research Collection School Of Computing and Information Systems

Despite the huge investments by organizations in ERP implementation, maintenance, and user training, ERP implementation failures and less-than-satisfactory productivity improvements are common. End-users’ reluctance or unwillingness to adopt or use the newly implemented ERP system is often cited as one of the main reasons for ERP failures. To examine factors leading to the lack of end-user acceptance of ERP systems, we reviewed the literature on user adoption of IT in mandatory contexts, developed hypotheses to explain ERP user acceptance, and conducted a survey study to test the hypotheses. In particular, we examined end-users’ attitudes toward system use and symbolic adoption, …

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Parameter Inference Of Queueing Models For It Systems Using End-To-End Measurements, Laura Wynter, Cathy H. Xia, Fan Zhang Jun 2004

Parameter Inference Of Queueing Models For It Systems Using End-To-End Measurements, Laura Wynter, Cathy H. Xia, Fan Zhang

Research Collection School Of Computing and Information Systems

he scope of available applications, IT systems increase at a fascinating rate in both size and complexity. For example, today, a typical Web service hosting center may have hundreds of nodes and dozens of different applications simultaneously running on it. Each of the nodes in turn has often multiple processors and layered caches. These nodes make use of both local and shared storage systems. The size and complexity of such systems make performance modeling much more difficult, if at all tractable. Detailed modeling, fine tuning and accurate analysis can be carried out only on very small IT systems or very …

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Cryptanalysis Of Two Anonymous Buyer-Seller Watermarking Protocols And An Improvement For True Anonymity, Bok-Min Goi, Raphael C. W. Phan, Yanjiang Yang, Feng Bao, Robert H. Deng, M. U. Siddiqi Jun 2004

Cryptanalysis Of Two Anonymous Buyer-Seller Watermarking Protocols And An Improvement For True Anonymity, Bok-Min Goi, Raphael C. W. Phan, Yanjiang Yang, Feng Bao, Robert H. Deng, M. U. Siddiqi

Research Collection School Of Computing and Information Systems

By combining techniques of watermarking and fingerprinting, a sound buyer-seller watermarking protocol can address the issue of copyright protection in e-commerce. In this paper, we analyze the security of two recent anonymous buyer-seller watermarking protocols proposed by Ju et. al and Choi et. al respectively, and prove that they do not provide the features and security as claimed. In particular, we show that i) the commutative cryptosystem used in Choi et. als protocol fails to prevent the watermark certification authority (WCA) from discovering the watermark (fingerprint) chosen by the buyer; ii) for both protocols, the seller can discover the watermark …

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The Complexity Of Uml: Differentiating Practical And Theoretical Complexity, J. Erickson, Keng Siau Jun 2004

The Complexity Of Uml: Differentiating Practical And Theoretical Complexity, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

UML (Unified Modeling Language) has been criticized for its complexity, relating to users, and those learning to use it. Using Rossi and Brinkkemper’s [9] complexity metrics, Siau and Cao [10] 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 [11] argued 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. The current research proposes that a subset of UML (a kernel) composed of the most commonly used constructs, would …

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Proprietary And Open Systems Adoption In E-Procurement: A Risk-Augmented Transactions Cost Perspective, Robert J. Kauffman, Hamid Mohtadi Jun 2004

Proprietary And Open Systems Adoption In E-Procurement: A Risk-Augmented Transactions Cost Perspective, Robert J. Kauffman, Hamid Mohtadi

Research Collection School Of Computing and Information Systems

We present an economic model that enables the study of incentives for business-to-business (B2B) e-procurement systems investments that permit inventory coordination and improved operational control. We focus on the information technology adoption behavior of firms in the presence of transaction costs, agency costs and information uncertainty. We conclude that it is appropriate to rethink the prior theory and develop an extended transaction-cost theory perspective that incorporates the possibility of shocks. We distinguish among three kinds of B2B e-procurement systems platforms. Proprietary platform procurement systems involve traditional electronic data interchange (EDI) technologies. Open platform procurement systems are associated with e-market Web …

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Furthering The Understanding Of Practical Complexity: Identifying A Kernel Of Uml, J. Erickson, Keng Siau Jun 2004

Furthering The Understanding Of Practical Complexity: Identifying A Kernel Of Uml, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

The Unified Modeling Language (UML) was adopted by the Object Management Group as the standard visual modeling language for OO systems development. However, UML has been criticized in the literature for its complexity, inconsistent semantics, and ambiguous constructs. A set of complexity indices for UML in aggregate, and the nine diagramming techniques individually, was compiled recently. Since this set of metrics is based on inclusion of all possible constructs in UML, it thus provides an indication of the theoretical (maximum) complexity of the modeling methods. This paper contends that in practice, developers do not use all of the possible diagrams …

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Steganographic Schemes For File System And B-Tree, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou Jun 2004

Steganographic Schemes For File System And B-Tree, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou

Research Collection School Of Computing and Information Systems

While user access control and encryption can protect valuable data from passive observers, these techniques leave visible ciphertexts that are likely to alert an active adversary to the existence of the data. We introduce StegFD, a steganographic file driver that securely hides user-selected files in a file system so that, without the corresponding access keys, an attacker would not be able to deduce their existence. Unlike other steganographic schemes proposed previously, our construction satisfies the prerequisites of a practical file system in ensuring the integrity of the files and maintaining efficient space utilization. We also propose two schemes for implementing …

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A Rate-Distortion Framework For Information-Theoretic Mobility Management, Abhishek Roy, Archan Misra, Sajal K. Das Jun 2004

A Rate-Distortion Framework For Information-Theoretic Mobility Management, Abhishek Roy, Archan Misra, Sajal K. Das

Research Collection School Of Computing and Information Systems

A practical information theoretic framework is developed for studying the optimal tradeoff between location update and paging costs in cellular networks. The framework envisions the quantization of location information into a registration area (RA) level granularity, followed by the use of an entropy-coding technique to decrease the location update rate. The rate distortion theory of the lossy quantization is identified as an appropriate measure for capturing the optimal tradeoff between a mobile's update rate and its location uncertainty. Based on LZ-78 compression, two different RA-level location update algorithms (RA-LeZi and LeZi-RA) have been developed, both of which asymptotically approach this …

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Tournament Versus Fitness Uniform Selection, Shane Legg, Marcus Hutter, Akshat Kumar Jun 2004

Tournament Versus Fitness Uniform Selection, Shane Legg, Marcus Hutter, Akshat Kumar

Research Collection School Of Computing and Information Systems

In evolutionary algorithms a critical parameter that must be tuned is that of selection pressure. If it is set too low then the rate of convergence towards the optimum is likely to be slow. Alternatively if the selection pressure is set too high the system is likely to become stuck in a local optimum due to a loss of diversity in the population. The recent Fitness Uniform Selection Scheme (FUSS) is a conceptually simple but somewhat radical approach to addressing this problem - rather than biasing the selection towards higher fitness, FUSS biases selection towards sparsely populated fitness levels. In …

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Multi-Period Multi-Dimensional Knapsack Problem And Its Application To Available-To-Promise, Hoong Chuin Lau, M. K. Lim May 2004

Multi-Period Multi-Dimensional Knapsack Problem And Its Application To Available-To-Promise, Hoong Chuin Lau, M. K. Lim

Research Collection School Of Computing and Information Systems

This paper is motivated by a recent trend in logistics scheduling, called Available-to-Promise. We model this problem as the multi-period multi-dimensional knapsack problem. We provide some properties for a special case of a single-dimensional problem. Based on insights obtained from these properties, we propose a two-phase heuristics for solving the multi-dimensional problem. We also propose a novel time-based ant colony optimization algorithm. The quality of the solutions generated is verified through experiments, where we demonstrate that the computational time is superior compared with integer programming to achieve solutions that are within a small percentage of the upper bounds.

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Toolglasses, Marking Menus, And Hotkeys: A Comparison Of One And Two-Handed Command Selection Techniques, Daniel L. Odell, Richard C. Davis, Andrew Smith, Paul K. Wright May 2004

Toolglasses, Marking Menus, And Hotkeys: A Comparison Of One And Two-Handed Command Selection Techniques, Daniel L. Odell, Richard C. Davis, Andrew Smith, Paul K. Wright

Research Collection School Of Computing and Information Systems

This paper introduces a new input technique, bimanual marking menus, and compares its performance with five other techniques: static toolbars, hotkeys, grouped hotkeys, marking menus, and toolglasses. The study builds on previous work by setting the comparison in a commonly encountered task, shape drawing. In this context, grouped hotkeys and bimanual marking menus were found to be the fastest. Subjectively, the most pre-ferred input method was bimanual marking menus. Toolglass performance was unexpectedly slow, which hints at the importance of low-level toolglass imple-mentation choices.

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Web Image Learning For Searching Semantic Concepts In Image Databases, Steven Hoi, Michael R. Lyu May 2004

Web Image Learning For Searching Semantic Concepts In Image Databases, Steven Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Without textual descriptions or label information of images, searching semantic concepts in image databases is still a very challenging task. While automatic annotation techniques are yet a long way off, we can seek other alternative techniques to solve this difficult issue. In this paper, we propose to learn Web images for searching the semantic concepts in large image databases. To formulate effective algorithms, we suggest to engage the support vector machines for attacking the problem. We evaluate our algorithm in a large image database and demonstrate the preliminary yet promising results.

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Modified Art 2a Growing Network Capable Of Generating A Fixed Number Of Nodes, Ji He, Ah-Hwee Tan, Chew-Lim Tan May 2004

Modified Art 2a Growing Network Capable Of Generating A Fixed Number Of Nodes, Ji He, Ah-Hwee Tan, Chew-Lim Tan

Research Collection School Of Computing and Information Systems

This paper introduces the Adaptive Resonance Theory under Constraint (ART-C 2A) learning paradigm based on ART 2A, which is capable of generating a user-defined number of recognition nodes through online estimation of an appropriate vigilance threshold. Empirical experiments compare the cluster validity and the learning efficiency of ART-C 2A with those of ART 2A, as well as three closely related clustering methods, namely online K-Means, batch K-Means, and SOM, in a quantitative manner. Besides retaining the online cluster creation capability of ART 2A, ART-C 2A gives the alternative clustering solution, which allows a direct control on the number of output …

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A Stage Model For E-Government Implementation, Keng Siau, Y. Long May 2004

A Stage Model For E-Government Implementation, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

With the advancement of wired and wireless technologies in recent years, the concept of an e-government has attracted increasing interests from both researchers and practitioners. The E-Government Act of 2002 was signed into law by President Bush to encourage government agencies to efficiently and effectively serve their customers over the Web. E-government presents a way for government agencies to use new technologies, such as the Internet, to provide citizens, businesses, and other governments with a 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 …

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Performance Planning, Quality-Of-Service, And Pricing Under Competition, Corinne Touati, Parijat Dube, Laura Wynter May 2004

Performance Planning, Quality-Of-Service, And Pricing Under Competition, Corinne Touati, Parijat Dube, Laura Wynter

Research Collection School Of Computing and Information Systems

In this work we model the relationship between the capacity and the Quality of Service (QoS) offered by the firm in a competitive scenario of two firm’s working to maximize their profits. Using simple queueing theoretic models we study the sensitivity of a firm’s market share to price, capacity and market size. Our preliminary studies yield important properties of the equilibrium solution which may further provide important “engineering” guidelines for performance planning and pricing strategies.

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Power Adaptation Based Optimization For Energy Efficient Reliable Wireless Paths, Suman Banerjee, Archan Misra May 2004

Power Adaptation Based Optimization For Energy Efficient Reliable Wireless Paths, Suman Banerjee, Archan Misra

Research Collection School Of Computing and Information Systems

We define a transmission power adaptation-based routing technique that finds optimal paths for minimum energy reliable data transfer in multi-hop wireless networks. This optimal choice of the transmission power depends on the link distance between the two nodes and the channel characteristics. Typical energy efficient routing techniques use a transmission power such that the received signal power at the destination minimally exceeds a desired threshold signal strength level. In this paper we argue that such a choice of the transmission power does not always lead to optimal energy routes, since it does not consider differences in the receiver noise levels.We …

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A Cost-Effective Critical Path Approach For Service Priority Optimization In The Grid Computing Economy, Mei Lin, Zhangxi Lin Apr 2004

A Cost-Effective Critical Path Approach For Service Priority Optimization In The Grid Computing Economy, Mei Lin, Zhangxi Lin

Research Collection School Of Computing and Information Systems

The advancement in the utilization and technologiesof the Internet has led to the rapid growth of gridcomputing; and the perpetuating demand for gridcomputing resources calls for an incentive-compatible solution to the imminent QoS problem. This paper examines the optimal service priority selection problem that a grid computing network user will confront. We model grid services for a multi-subtask request as a prioritized PERT graph and prove that the localized conditional critical path, which is based on the cost-minimizin gpriority selection for each node, sets the lower bound for the length of cost-effective critical path that commits the optimal solution. We …

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Dynamic Offloading In A Multi-Provider Environment: A Behavioral Framework For Use In Influencing Peering, Zhen Liu, Vishal Misra, Laura Wynter Apr 2004

Dynamic Offloading In A Multi-Provider Environment: A Behavioral Framework For Use In Influencing Peering, Zhen Liu, Vishal Misra, Laura Wynter

Research Collection School Of Computing and Information Systems

We pose the question of how to encourage the resource sharing in a distributed, multi-provider environment, where each node, or provider, has local work but is able to accept additional work from other nodes/providers if there is available capacity. An instance of such an environment is found in content delivery, where. numerous, competing providers can work together if enough benefit is to be gained from doing so. We model individual provider behavior as essentially selfish, and then propose pricing schemes to exploit the selfishness to achieve system wide performance gains. We employ a game theoretic framework to analyze the problem, …

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Phoneme-Based Transliteration Of Foreign Names For Oov Problem, Wei Gao, Kam-Fai Wong, Wai Lam Mar 2004

Phoneme-Based Transliteration Of Foreign Names For Oov Problem, Wei Gao, Kam-Fai Wong, Wai Lam

Research Collection School Of Computing and Information Systems

A proper noun dictionary is never complete rendering name translation from English to Chinese ineffective. One way to solve this problem is not to rely on a dictionary alone but to adopt automatic translation according to pronunciation similarities, i.e. to map phonemes comprising an English name to the phonetic representations of the corresponding Chinese name. This process is called transliteration. We present a statistical transliteration method. An efficient algorithm for aligning phoneme chunks is described. Unlike rule-based approaches, our method is data-driven. Compared to source-channel based statistical approaches, we adopt a direct transliteration model, i.e. the direction of probabilistic estimation …

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Efficient Group Pattern Mining Using Data Summarization, Yida Wang, Ee Peng Lim, San-Yih Hwang Mar 2004

Efficient Group Pattern Mining Using Data Summarization, Yida Wang, Ee Peng Lim, San-Yih Hwang

Research Collection School Of Computing and Information Systems

In group pattern mining, we discover group patterns from a given user movement database based on their spatio-temporal distances. When both the number of users and the logging duration are large, group pattern mining algorithms become very inefficient. In this paper, we therefore propose a spherical location summarization method to reduce the overhead of mining valid 2-groups. In our experiments, we show that our group mining algorithm using summarized data may require much less execution time than that using non-summarized data.

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Effects Of Query Complexity And Learning On Novice User Query Performance With Conceptual And Logical Database Interfaces, Keng Siau, Hock Chuan Chan, Kwok Kee Wei Mar 2004

Effects Of Query Complexity And Learning On Novice User Query Performance With Conceptual And Logical Database Interfaces, Keng Siau, Hock Chuan Chan, Kwok Kee Wei

Research Collection School Of Computing and Information Systems

Users see the database interface as the database system. A good interface enables them to formulate queries better. The semantics communicated through the interface can be classified according to abstraction levels, such as the conceptual and logical levels. With the conceptual interface, interaction is in terms of real-world concepts such as entities, objects and relationships. Current user-database interaction is mainly based on the logical interface, where interaction is in terms of abstract database concepts such as relations and joins. Many researchers argue that end users will perform better with the conceptual interface. This research tested this claim, as well as …

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A Smart-Card-Enabled Privacy Preserving E-Prescription System, Yanjiang Yang, Xiaoxi Han, Feng Bao, Robert H. Deng Mar 2004

A Smart-Card-Enabled Privacy Preserving E-Prescription System, Yanjiang Yang, Xiaoxi Han, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Within the overall context of protection of health care information, privacy of prescription data needs special treatment. First, the involvement of diverse parties, especially nonmedical parties in the process of drug prescription complicates the protection of prescription data. Second, both patients and doctors have privacy stakes in prescription, and their privacy should be equally protected. Third, the following facts determine that prescription should not be processed in a truly anonymous manner: certain involved parties conduct useful research on the basis of aggregation of prescription data that are linkable with respect to either the patients or the doctors; prescription data has …

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An Information-Theoretic Framework For Optimal Location Tracking In Multi-System 4g Wireless Networks, Archan Misra, Abhishek Roy, Sajal K. Das Mar 2004

An Information-Theoretic Framework For Optimal Location Tracking In Multi-System 4g Wireless Networks, Archan Misra, Abhishek Roy, Sajal K. Das

Research Collection School Of Computing and Information Systems

An information-theoretic framework is developed for optimal location management in multisystem, fourth generation (4G) wireless networks. The framework envisions that each individual subsystem operates fairly independently, and does not require public knowledge of individual subnetwork topologies. To capture the variation in paging and location update costs in this heterogeneous environment, the location management problem is formulated in terms of a new concept of weighted entropy. The update process is based on the Lempel-Ziv compression algorithms, which are applied to a vector-valued sequence consisting of both the mobile's movement pattern and its session activity state. Three different tracking strategies which differ …

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