Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Research Collection School Of Computing and Information Systems

2006

Discipline
Keyword

Articles 91 - 112 of 112

Full-Text Articles in Physical Sciences and Mathematics

In-Network Processing Of Nearest Neigbor Queries For Wireless Sensor Networks, Yuxia Yao, Xueyan Tang, Ee Peng Lim Apr 2006

In-Network Processing Of Nearest Neigbor Queries For Wireless Sensor Networks, Yuxia Yao, Xueyan Tang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Wireless sensor networks have been widely used for civilian and military applications, such as environmental monitoring and vehicle tracking. The sensor nodes in the network have the abilities to sense, store, compute and communicate. To enable object tracking applications, spatial queries such as nearest neighbor queries are to be supported in these networks. The queries can be injected by the user at any sensor node. Due to the limited power supply for sensor nodes, energy efficiency is the major concern in query processing. Centralized data storage and query processing schemes do not favor energy efficiency. In this paper, we propose …

Go to article

A Practical Password-Based Two-Server Authentication And Key Exchange System, Yanjiang Yang, Robert H. Deng, Feng Bao Apr 2006

A Practical Password-Based Two-Server Authentication And Key Exchange System, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Most password-based user authentication systems place total trust on the authentication server where cleartext passwords or easily derived password verification data are stored in a central database. Such systems are, thus, by no means resilient against offline dictionary attacks initiated at the server side. Compromise of the authentication server by either outsiders or insiders subjects all user passwords to exposure and may have serious legal and financial repercussions to an organization. Recently, several multiserver password systems were proposed to circumvent the single point of vulnerability inherent in the single-server architecture. However, these multiserver systems are difficult to deploy and operate …

Go to article

Efficient Client-To-Server Assignments For Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou Apr 2006

Efficient Client-To-Server Assignments For Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou

Research Collection School Of Computing and Information Systems

Distributed Virtual Environments (DVEs) are distributed systems that allow multiple geographically distributed clients (users) to interact simultaneously in a computer-generated, shared virtual world. Applications of DVEs can be seen in many areas nowadays, such as online games, military simulations, collaborative designs, etc. To support large-scale DVEs with real-time interactions among thousands or more distributed clients, a geographically distributed server architecture (GDSA) is generally needed, and the virtual world can be partitioned into many distinct zones to distribute the load among the servers. Due to the geographic distributions of clients and servers in such architectures, it is essential to efficiently assign …

Go to article

Threading And Autodocumenting News Videos: A Promising Solution To Rapidly Browse News Topics, Xiao Wu, Chong-Wah Ngo, Qing Li Mar 2006

Threading And Autodocumenting News Videos: A Promising Solution To Rapidly Browse News Topics, Xiao Wu, Chong-Wah Ngo, Qing Li

Research Collection School Of Computing and Information Systems

This paper describes the techniques in threading and autodocumenting news stories according to topic themes. Initially, we perform story clustering by exploiting the duality between stories and textual-visual concepts through a co-clustering algorithm. The dependency among stories of a topic is tracked by exploring the textual-visual novelty and redundancy of stories. A novel topic structure that chains the dependencies of stories is then presented to facilitate the fast navigation of the news topic. By pruning the peripheral and redundant news stories in the topic structure, a main thread is extracted for autodocumentary

Go to article

Publicly Verifiable Ownership Protection For Relational Databases, Yingjiu Li, Robert H. Deng Mar 2006

Publicly Verifiable Ownership Protection For Relational Databases, Yingjiu Li, Robert H. Deng

Research Collection School Of Computing and Information Systems

Today, watermarking techniques have been extended from the multimedia context to relational databases so as to protect the ownership of data even after the data are published or distributed. However, all existing watermarking schemes for relational databases are secret key based, thus require a secret key to be presented in proof of ownership. This means that the ownership can only be proven once to the public (e.g., to the court). After that, the secret key is known to the public and the embedded watermark can be easily destroyed by malicious users. Moreover, most of the existing techniques introduce distortions to …

Go to article

Crosscutting Score: An Indicator Metric For Aspect Orientation, Subhajit Datta Mar 2006

Crosscutting Score: An Indicator Metric For Aspect Orientation, Subhajit Datta

Research Collection School Of Computing and Information Systems

Aspect Oriented Programming (AOP) provides powerful techniques for modeling and implementing enterprise software systems. To leverage its full potential, AOP needs to be perceived in the context of existing methodologies such as Object Oriented Programming (OOP). This paper addresses an important question for AOP practitioners - how to decide whether a component is best modeled as a class or an aspect? Towards that end, we present an indicator metric, the Crosscutting Score and a method for its calculation and interpretation. We will illustrate our approach through a sample calculation.

Go to article

Caps: Energy-Efficient Processing Of Continuous Aggregate Queries In Sensor Networks, Wen Hu, Archan Misra, Rajiv Shorey Mar 2006

Caps: Energy-Efficient Processing Of Continuous Aggregate Queries In Sensor Networks, Wen Hu, Archan Misra, Rajiv Shorey

Research Collection School Of Computing and Information Systems

In this paper, we design and evaluate an energy efficient data retrieval architecture for continuous aggregate queries in wireless sensor networks. We show how the modification of precision in one sensor affects the sample-reporting frequency of other sensors, and how the precisions of a group of sensors may be collectively modified to achieve the target quality of information (QoI) with higher energy-efficiency. The proposed collective adaptive precision setting (CAPS) architecture is then extended to exploit the observed temporal correlation among successive sensor samples for even greater energy efficiency. Detailed simulations with synthetic and real data traces demonstrate how the combination …

Go to article

Fortifying Password Authentication In Integrated Healthcare Delivery Systems, Yanjiang Yang, Robert H. Deng, Feng Bao Mar 2006

Fortifying Password Authentication In Integrated Healthcare Delivery Systems, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Integrated Delivery Systems (IDSs) now become a primary means of care provision in healthcare domain. However, existing password systems (under either the single-server model or the multi-server model) do not provide adequate security when applied to IDSs. We are thus motivated to present a practical password authentication system built upon a novel two-server model. We generalize the two-server model to an architecture of a single control server supporting multiple service servers, tailored to the organizational structure of IDSs. The underlying user authentication and key exchange protocols we propose are password-only, neat, efficient, and robust against off-line dictionary attacks mounted by …

Go to article

Robust Classification Of Eeg Signal For Brain-Computer Interface, Manoj Thulasidas, Cuntai Guan, Jiankang Wu Mar 2006

Robust Classification Of Eeg Signal For Brain-Computer Interface, Manoj Thulasidas, Cuntai Guan, Jiankang Wu

Research Collection School Of Computing and Information Systems

We report the implementation of a text input application (speller) based on the P300 event related potential. We obtain high accuracies by using an SVM classifier and a novel feature. These techniques enable us to maintain fast performance without sacrificing the accuracy, thus making the speller usable in an online mode. In order to further improve the usability, we perform various studies on the data with a view to minimizing the training time required. We present data collected from nine healthy subjects, along with the high accuracies (of the order of 95% or more) measured online. We show that the …

Go to article

Agility Measurement Index: A Metric For The Crossroads Of Software Development Methodologies, Subhajit Datta Mar 2006

Agility Measurement Index: A Metric For The Crossroads Of Software Development Methodologies, Subhajit Datta

Research Collection School Of Computing and Information Systems

Software engineering's journey to maturity has been marked by the advent of different development methodologies. While each paradigm has its context and cognoscenti, project teams are often faced with the choice of one approach over another in the grind of delivering software on time and within budget. In this paper, we briefly review the three major techniques of addressing enterprise software development, namely the Waterfall, Unified and Extreme styles. The metric Agility Measurement Index is then proposed, which helps organizations choose the methodology that best suites a particular project.

Go to article

Tacit Knowledge, Nonaka And Takeuchi Seci Model And Informal Knowledge Processes, Siu Loon Hoe Mar 2006

Tacit Knowledge, Nonaka And Takeuchi Seci Model And Informal Knowledge Processes, Siu Loon Hoe

Research Collection School Of Computing and Information Systems

The organizational behavior and knowledge management literature has devoted a lot attention on how structural knowledge processes enhance learning. There has been little emphasis on the informal knowledge processes and the construct remains undefined. The purpose of this paper is to highlight the importance of informal knowledge processes, propose a definition for these processes and link them to the socialization and internalization processes suggested by Nonaka and Takeuchi in the SECI model. The paper offers a fresh perspective on how informal knowledge processes in organizations help to enhance the organization’s learning capability. It will enable scholars and managers to have …

Go to article

Energy Efficiency And Capacity For Tcp Traffic In Multi-Hop Wireless Networks, Sorav Bansal, Rajeev Shorey, Rajeev Gupta, Archan Misra Feb 2006

Energy Efficiency And Capacity For Tcp Traffic In Multi-Hop Wireless Networks, Sorav Bansal, Rajeev Shorey, Rajeev Gupta, Archan Misra

Research Collection School Of Computing and Information Systems

We study the performance metrics associated with TCP-regulated traffic in multi-hop, wireless networks that use a common physical channel (e.g., IEEE 802.11). In contrast to earlier analyses, we focus simultaneously on two key operating metrics—the energy efficiency and the transport-layer (TCP) throughput. Using analysis and simulations, we show how these metrics are strongly influenced by the radio transmission range of individual nodes. Due to tradeoffs between the individual packet transmission energy and the likelihood of retransmissions, the total energy consumption is a convex function of the number of hops (and hence, of the transmission range). On the other hand, the …

Go to article

Scalable Authentication Of Mpeg-4 Streams, Yongdong Wu, Robert H. Deng Feb 2006

Scalable Authentication Of Mpeg-4 Streams, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

This paper presents three scalable and efficient schemes for authenticating MPEG-4 streams: the Flat Authentication Scheme, the Progressive Authentication Scheme, and the Hierarchical Authentication Scheme. All the schemes allow authentication of MPEG-4 streams over lossy networks by integrating seamlessly digital signatures and erasure correction coding with MPEG-4's fine granular scalability. A prominent feature of our schemes is their "sign once, verify many ways" property, i.e., they generate only one digital signature per compressed MPEG-4 object group, but allow clients to verify the authenticity of any down-scaled version of the original signed object group.

Go to article

Design Synthesis From Interaction And State-Based Specifications, Jun Sun, Jin Song Dong Jan 2006

Design Synthesis From Interaction And State-Based Specifications, Jun Sun, Jin Song Dong

Research Collection School Of Computing and Information Systems

Interaction-based and state-based modeling are two complementary approaches of behavior modeling. The former focuses on global interactions between system components. The latter concentrates on the internal states of individual components. Both approaches have been proven useful in practice. One challenging and important research objective is to combine the modeling power of both effectively and then use the combination as the basis for automatic design synthesis. We present a combination of interaction-based and state-based modeling, namely, Live Sequence Charts and Z, for system specification. We then propose a way of generating distributed design from the combinations. Our approach handles systems with …

Go to article

Visualization For Analyzing Trajectory-Based Metaheuristic Search Algorithms, Steven Halim, Roland H. C. Yap, Hoong Chuin Lau Jan 2006

Visualization For Analyzing Trajectory-Based Metaheuristic Search Algorithms, Steven Halim, Roland H. C. Yap, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

No abstract provided.

Go to article

Multiagent Teamwork: Hybrid Approaches, Praveen Paruchuri, Emma Bowring, Ranjit Nair, Jonathan Pearce, Nathan Schurr, Milind Tambe, Pradeep Varakantham Jan 2006

Multiagent Teamwork: Hybrid Approaches, Praveen Paruchuri, Emma Bowring, Ranjit Nair, Jonathan Pearce, Nathan Schurr, Milind Tambe, Pradeep Varakantham

Research Collection School Of Computing and Information Systems

Today within the multiagent community, we see at least four competing methods to building multiagent systems: beliefdesireintention (BDI), distributed constraint optimization (DCOP), distributed POMDPs, and auctions or game-theoretic methods. While there is exciting progress within each approach, there is a lack of cross-cutting research. This article highlights the various hybrid techniques for multiagent teamwork developed by the teamcore group. In particular, for the past decade, the TEAMCORE research group has focused on building agent teams in complex, dynamic domains. While our early work was inspired by BDI, we will present an overview of recent research that uses DCOPs and distributed …

Go to article

The Impact Of Financial Market And Resale Market On Firm Strategies, Zhiling Guo, Andrew B. Whinston Jan 2006

The Impact Of Financial Market And Resale Market On Firm Strategies, Zhiling Guo, Andrew B. Whinston

Research Collection School Of Computing and Information Systems

The ever-increasing use of information technology (IT) in business transactions greatly expands firms? exposure to different electronic markets. This paper provides a framework to understand how firms can leverage different strategies across external financial markets and an internal resale market to improve overall profitability. We develop a model in which a group of risk-averse retailers sell a homogeneous product to their respective uncertain consumer markets. We study a scenario where an internal resale market can be constructed among the retailers and outside financial markets can be used to improve their ability to manage uncertainty. We identify strategies for retailers operating …

Go to article

Towards Better Quality Specification Miners, David Lo, Siau-Cheng Khoo Jan 2006

Towards Better Quality Specification Miners, David Lo, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Softwares are often built without specification. Tools to automatically extract specification from software are needed and many techniques have been proposed. One type of these specifications – temporal API specification – is often specified in the form of automaton (i.e., FSA/PFSA). There have been many work on mining software temporal specification using dynamic analysis techniques; i.e., analysis of software program traces. Unfortunately, the issues of scalability, robustness and accuracy of these techniques have not been comprehensively addressed. In this paper, we describe a framework that enables assessments of the performance of a specification miner in generating temporal specification of software …

Go to article

In-Network Join Processing For Sensor Networks, Hai Yu, Ee Peng Lim, Jun Zhang Jan 2006

In-Network Join Processing For Sensor Networks, Hai Yu, Ee Peng Lim, Jun Zhang

Research Collection School Of Computing and Information Systems

Recent advances in hardware and wireless technologies have led to sensor networks consisting of large number of sensors capable of gathering and processing data collectively. Query processing on these sensor networks has to consider various inherent constraints. While simple queries such as select and aggregate queries in wireless sensor networks have been addressed in the literature, the processing of join queries in sensor networks remains to be investigated. In this paper, we present a synopsis join strategy for evaluating join queries in sensor networks with communication efficiency. In this strategy, instead of directly joining two relations distributed in a sensor …

Go to article

Grid-Partition Index: A Hybrid Approach To Nearest-Neighbor Queries In Wireless Location-Based Services, Baihua Zheng, Jianliang Xu, Wang-Chien Lee, Dik Lun Lee Jan 2006

Grid-Partition Index: A Hybrid Approach To Nearest-Neighbor Queries In Wireless Location-Based Services, Baihua Zheng, Jianliang Xu, Wang-Chien Lee, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Traditional nearest-neighbor (NN) search is based on two basic indexing approaches: object-based indexing and solution-based indexing. The former is constructed based on the locations of data objects: using some distance heuristics on object locations. The latter is built on a precomputed solution space. Thus, NN queries can be reduced to and processed as simple point queries in this solution space. Both approaches exhibit some disadvantages, especially when employed for wireless data broadcast in mobile computing environments. In this paper, we introduce a new index method, called the grid-partition index, to support NN search in both ondemand access and periodic broadcast …

Go to article

Efficient Mining Of Group Patterns From User Movement Data, Yida Wang, Ee Peng Lim, San-Yih Hwang Jan 2006

Efficient Mining Of Group Patterns From User Movement Data, Yida Wang, Ee Peng Lim, San-Yih Hwang

Research Collection School Of Computing and Information Systems

In this paper, we present a new approach to derive groupings of mobile users based on their movement data. We assume that the user movement data are collected by logging location data emitted from mobile devices tracking users. We formally define group pattern as a group of users that are within a distance threshold from one another for at least a minimum duration. To mine group patterns, we first propose two algorithms, namely AGP and VG-growth. In our first set of experiments, it is shown when both the number of users and logging duration are large, AGP and VG-growth are …

Go to article

The Roles Of Digital Libraries In Teaching And Learning Geography, Chew-Hung Chang, John Hedberg, Tiong-Sa Teh, Ee Peng Lim Jan 2006

The Roles Of Digital Libraries In Teaching And Learning Geography, Chew-Hung Chang, John Hedberg, Tiong-Sa Teh, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Adopting a problem-centred approach helps students to learn Geography more effectively as they are able to identify and generalize about where different resources or activities are spatially located and they learn to associate certain patterns and processes with geographical changes. In an era where web-based student-centred inquiry is gaining popularity as a mode of learning Geography, the role of digital libraries as delivery trucks (in Clark’s terminology, 1983) needs to be better understood. An obvious affordance of the digital library is that it organizes information around themes for problems to be solved. This paper describes a developmental project to build …

Go to article

First Prev