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Full-Text Articles in Physical Sciences and Mathematics

Xstamps: A Multiversion Timestamps Concurrency Control Protocol For Xml Data, Khin-Myo Win, Wee-Keong Ng, Ee Peng Lim Dec 2003

Xstamps: A Multiversion Timestamps Concurrency Control Protocol For Xml Data, Khin-Myo Win, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

With the tremendous growth of XML data over the Web, efficient management of such data becomes a new challenge for database community. Several data management solutions, proposed in recent years, extend the capability of traditional database systems to meet the needs of XML data while alternative approaches introduce new generation databases, named as native XML database management systems. Although traditional databases have mature transaction management and concurrency control techniques, there is still a need to tailor techniques for native XML databases in order to deal with distinct characteristics of XML. In this paper, we propose XStamps, a multiversion timestamps concurrency …


Predicting Nonlinear Network Traffic Using Fuzzy Neural Network, Zhaoxia Wang, Tingzhu Hao, Zengqiang Chen, Zhuzhi Yuan Dec 2003

Predicting Nonlinear Network Traffic Using Fuzzy Neural Network, Zhaoxia Wang, Tingzhu Hao, Zengqiang Chen, Zhuzhi Yuan

Research Collection School Of Computing and Information Systems

Network traffic is a complex and nonlinear process, which is significantly affected by immeasurable parameters and variables. This paper addresses the use of the five-layer fuzzy neural network (FNN) for predicting the nonlinear network traffic. The structure of this system is introduced in detail. Through training the FNN using back-propagation algorithm with inertia] terms the traffic series can be well predicted by this FNN system. We analyze the performance of the FNN in terms of prediction ability as compared with solely neural network. The simulation demonstrates that the proposed FNN is superior to the solely neural network systems. In addition, …


Structuring Lecture Videos For Distance Learning Applications, Chong-Wah Ngo, Feng Wang, Ting-Chuen Pong Dec 2003

Structuring Lecture Videos For Distance Learning Applications, Chong-Wah Ngo, Feng Wang, Ting-Chuen Pong

Research Collection School Of Computing and Information Systems

This paper presents an automatic and novel approach in structuring and indexing lecture videos for distance learning applications. By structuring video content, we can support both topic indexing and semantic querying of multimedia documents. In this paper, our aim is to link the discussion topics extracted from the electronic slides with their associated video and audio segments. Two major techniques in our proposed approach include video text analysis and speech recognition. Initially, a video is partitioned into shots based on slide transitions. For each shot, the embedded video texts are detected, reconstructed and segmented as high-resolution foreground texts for commercial …


Paper For An Educational Digital Library, Dion Hoe-Lian Goh, Yin-Leng Theng, Ming Yin, Ee Peng Lim Dec 2003

Paper For An Educational Digital Library, Dion Hoe-Lian Goh, Yin-Leng Theng, Ming Yin, Ee Peng Lim

Research Collection School Of Computing and Information Systems

GeogDL is a digital library of geography examination resources designed to assist students in revising for a national geography examination in Singapore. As part of an iterative design process, we carried out participatory design and brainstorming with student and teacher design partners. The first study involved prospective student design partners. In response to the first study, we describe in this paper an implementation of PAPER – Personalised Adaptive Pathways for Exam Resources – a new bundle of personalized, interactive services containing a mock exam and a personal coach. The mock exam provides a simulation of the actual geography examination while …


Synchronization Of Lecture Videos And Electronic Slides By Video Text Analysis, Feng Wang, Chong-Wah Ngo, Ting-Chuen Pong Nov 2003

Synchronization Of Lecture Videos And Electronic Slides By Video Text Analysis, Feng Wang, Chong-Wah Ngo, Ting-Chuen Pong

Research Collection School Of Computing and Information Systems

An essential goal of structuring lecture videos captured in live presentation is to provide a synchronized view of video clips and electronic slides. This paper presents an automatic approach to match video clips and slides based on the analysis of text embedded in lecture videos. We describe a method to reconstruct high-resolution video texts from multiple keyframes for robust OCRrecognition. A two-stage matching algorithm based on the title and content similarity measures between video clips and slides is also proposed.


Apparatus For Discovering Computing Services Architecture And Developing Patterns Of Computing Services And Method Therefor [Sg 107499], Emarson Victoria, Hui Tseng, Hwee Hwa Pang, Tau Chen Cham, Siew Choo Tay Nov 2003

Apparatus For Discovering Computing Services Architecture And Developing Patterns Of Computing Services And Method Therefor [Sg 107499], Emarson Victoria, Hui Tseng, Hwee Hwa Pang, Tau Chen Cham, Siew Choo Tay

Research Collection School Of Computing and Information Systems

An apparatus for discovering computing services architecture and developing patterns of computing services and method therefor are disclosed. The apparatus, according to an embodiment of the invention, provides a graphical user interface for displaying a deployment plan of deployed computing services. Components in the deployment plan are interconnected by links indicating dependency relationships between the components. Each component and link is assigned a confidence value, which is based on a calculated weight of the properties of each component. The apparatus further provides editing tools for manipulating the components in the deployment plan as well as for creating and managing patterns.


A Robust Dissolve Detector By Support Vector Machine, Chong-Wah Ngo Nov 2003

A Robust Dissolve Detector By Support Vector Machine, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we propose a novel approach for the robust detection and classification of dissolve sequences in videos. Our approach is based on the multi-resolution representation of temporal slices extracted from 3D image volume. At the low-resolution (LR) scale, the problem of dissolve detection is reduced as cut transition detection. At the highresolution (HR) space, Gabor wavelet features are computed for regions that surround the cuts located at LR scale. The computed features are then input to support vector machines for pattern classification. Encouraging results have been obtained through experiments.


Task Allocation Via Multi-Agent Coalition Formation: Taxonomy, Algorithms And Complexity, Hoong Chuin Lau, L. Zhang Nov 2003

Task Allocation Via Multi-Agent Coalition Formation: Taxonomy, Algorithms And Complexity, Hoong Chuin Lau, L. Zhang

Research Collection School Of Computing and Information Systems

Coalition formation has become a key topic in multiagent research. In this paper, we propose a preliminary classification for the coalition formation problem based on three driving factors (demands, resources and profit objectives). We divide our analysis into 5 cases. For each case, we present algorithms and complexity results. We anticipate that with future research, this classification can be extended in similar fashion to the comprehensive classification for the job scheduling problem.


Content-Aware Authentication Of Motion Jpeg2000 Stream In Lossy Networks, Yongdong Wu, Robert H. Deng Nov 2003

Content-Aware Authentication Of Motion Jpeg2000 Stream In Lossy Networks, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

Stream authentication schemes (SAS) aim to achieve effective authentication of multicast streams over lossy networks. Almost all the existing SASs is designed for stream data integrity protection only. In this paper, we argue that content integrity protection is more important than data integrity to human users. We present a content-aware SAS in motion JPEG2000 streaming. In our scheme, a chunk of JPEG2000 codestreams is encapsulated into a block of packets using multiple description coding (MDC). Our MDC exploits the inherent structure of motion JPEG2000 codestreams and is used to preserve the semanteme/content of the stream over lossy networks. To achieve …


Web Unit Mining: Finding And Classifying Subgraphs Of Web Pages, Aixin Sun, Ee Peng Lim Nov 2003

Web Unit Mining: Finding And Classifying Subgraphs Of Web Pages, Aixin Sun, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In web classification, most researchers assume that the objects to classify are individual web pages from one or more web sites. In practice, the assumption is too restrictive since a web page itself may not always correspond to a concept instance of some semantic concept (or category) given to the classification task. In this paper, we want to relax this assumption and allow a concept instance to be represented by a subgraph of web pages or a set of web pages. We identify several new issues to be addressed when the assumption is removed, and formulate the web unit mining …


Aa Flexible And Scalable Authentication Scheme For Jpeg 2000 Image Codestreams, Cheng Peng, Robert H. Deng, Yongdong Wu, Weizhong Shao Nov 2003

Aa Flexible And Scalable Authentication Scheme For Jpeg 2000 Image Codestreams, Cheng Peng, Robert H. Deng, Yongdong Wu, Weizhong Shao

Research Collection School Of Computing and Information Systems

JPEG2000 is an emerging standard for still image compression and is becoming the solution of choice for many digital imaging fields and applications. An important aspect of JPEG2000 is its "compress once, decompress many ways" property [1], i. e., it allows extraction of various sub-images (e.g., images with various resolutions, pixel fidelities, tiles and components) all from a single compressed image codestream. In this paper, we present a flexible and scalable authentication scheme for JPEG2000 images based on the Merkle hash tree and digital signature. Our scheme is fully compatible with JPEG2000 and possesses a "sign once, verify many ways" …


An Efficient Public-Key Framework, Jianying Zhou, Feng Bao, Robert H. Deng Oct 2003

An Efficient Public-Key Framework, Jianying Zhou, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Public-key certificates play an important role in binding the public key with the identity of the owner of the corresponding private key. A certificate might be revoked before its scheduled expiry date by the issuing CA. Efficient and timely distribution of certificate revocation information is a big challenge facing the PKI providers. Existing certificate revocation schemes place a considerable processing, communication, and storage overheads on the CA as well as the relying parties. To improve the current situation, we propose a revocation-free public-key framework, in which the maximum lifetime of a certificate is divided into short periods and the certificate …


Safe Robot Driving In Cluttered Environments, Chuck Thorpe, Justin Carlson, Dave Duggins, Jay Gowdy, Rob Maclachlan, Christoph Mertz, Arne Suppe, Bob Wang Oct 2003

Safe Robot Driving In Cluttered Environments, Chuck Thorpe, Justin Carlson, Dave Duggins, Jay Gowdy, Rob Maclachlan, Christoph Mertz, Arne Suppe, Bob Wang

Research Collection School Of Computing and Information Systems

The Navlab group at Carnegie Mellon University has a long history of development of automated vehicles and intelligent systems for driver assistance. The earlier work of the group concentrated on road following, cross-country driving, and obstacle detection. The new focus is on short-range sensing, to look all around the vehicle for safe driving. The current system uses video sensing, laser rangefinders, a novel light-stripe rangefinder, software to process each sensor individually, and a map-based fusion system. The complete system has been demonstrated on the Navlab 11 vehicle for monitoring the environment of a vehicle driving through a cluttered urban environment, …


Automatic Video Summarization By Graph Modeling, Chong-Wah Ngo, Yu-Fei Ma, Hong-Jiang Zhang Oct 2003

Automatic Video Summarization By Graph Modeling, Chong-Wah Ngo, Yu-Fei Ma, Hong-Jiang Zhang

Research Collection School Of Computing and Information Systems

We propose a unified approach for summarization based on the analysis of video structures and video highlights. Our approach emphasizes both the content balance and perceptual quality of a summary. Normalized cut algorithm is employed to globally and optimally partition a video into clusters. A motion attention model based on human perception is employed to compute the perceptual quality of shots and clusters. The clusters, together with the computed attention values, form a temporal graph similar to Markov chain that inherently describes the evolution and perceptual importance of video clusters. In our application, the flow of a temporal graph is …


Making The Key Agreement Protocol In Mobile Ad Hoc Network More Efficient, Gang Yao, Kui Ren, Feng Bao, Robert H. Deng, Dengguo Feng Oct 2003

Making The Key Agreement Protocol In Mobile Ad Hoc Network More Efficient, Gang Yao, Kui Ren, Feng Bao, Robert H. Deng, Dengguo Feng

Research Collection School Of Computing and Information Systems

Mobile ad hoc networks offer convenient infrastructureless communications over the shared wireless channel. However, the nature of mobile ad hoc networks makes them vulnerable to security attacks, such as passive eavesdropping over the wireless channel and denial of service attacks by malicious nodes. To ensure the security, several cryptography protocols are implemented. Due to the resource scarcity in mobile ad hoc networks, the protocols must be communication efficient and need as less computational power as possible. Broadcast communication is an important operation for many application in mobile ad hoc networks. To securely broadcast a message, all the members in the …


An Efficient Known Plaintext Attack On Fea-M, Hongjun Wu, Feng Bao, Robert H. Deng Oct 2003

An Efficient Known Plaintext Attack On Fea-M, Hongjun Wu, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Yi et al. have proposed a cipher called the fast encryption algorithm for multimedia (FEA-M). Recently Mihaljevi and Kohno pointed out that FEA-M is insecure. However, their attacks are not efficient: their chosen plaintext attack and known plaintext attack require 237-bit chosen plaintext and 260-bit known plaintext, respectively. In this paper we give an efficient known plaintext attack against FEA-M. Our attack requires only 228-bit known plaintext and about 233 XOR operations.


Validating Digital Signatures Without Ttp’S Time-Stamping And Certificate Revocation, Jianying Zhou, Feng Bao, Robert H. Deng Oct 2003

Validating Digital Signatures Without Ttp’S Time-Stamping And Certificate Revocation, Jianying Zhou, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

In non-repudiation services where digital signatures usually serve as irrefutable cryptographic evidence for dispute resolution, trusted time-stamping and certificate revocation services, although very costly in practice, must be available, to prevent big loss due to compromising of the signing key. In [12], a new concept called intrusion-resilient signature was proposed to get rid of trusted time-stamping and certificate revocation services and a concrete scheme was presented. In this paper, we put forward a new scheme that can achieve the same effect in a much more efficient way. In our scheme, forward-secure signature serves as a building block that enables signature …


Multi-Agent Coalition Via Autonomous Price Negotiation In A Real-Time Web Environment, Hoong Chuin Lau, Wei Sian Lim Oct 2003

Multi-Agent Coalition Via Autonomous Price Negotiation In A Real-Time Web Environment, Hoong Chuin Lau, Wei Sian Lim

Research Collection School Of Computing and Information Systems

In e-marketplaces, customers specify job requests in real-time and agents form coalitions to service them. This paper proposes a protocol for self-interested agents to negotiate prices in forming successful coalitions. We propose and experiment with two negotiation schemes: one allows information sharing while the other does not.


Adaptive Collusion Attack To A Block Oriented Watermarking Scheme, Yongdong Wu, Robert H. Deng Oct 2003

Adaptive Collusion Attack To A Block Oriented Watermarking Scheme, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

In this paper, we propose an adaptive collusion attack to a block oriented watermarking scheme [1]. In this attack, traitors conspire to selectively manipulate watermarked blocks to remove the watermark information. To this end, the traitors compare the watermarked blocks generated from the same original block. If two watermarked block are not equal, they average these two blocks to generate a pirated block. Then, replace the watermarked blocks with the pirated blocks so as to build a pirated image. The pirated image has no watermark but has much higher quality than watermarked images. We also give a theoretical analysis on …


High-Performance Architectures For Ip-Based Multihop 802.11 Networks, Arup Acharya, Archan Misra, Sorav Bansal Oct 2003

High-Performance Architectures For Ip-Based Multihop 802.11 Networks, Arup Acharya, Archan Misra, Sorav Bansal

Research Collection School Of Computing and Information Systems

The concept of a forwarding node, which receives packets from upstream nodes and then transmits these packets to downstream nodes, is a key element of any multihop network, wired or wireless. While high-speed IP router architectures have been extensively studied for wired networks, the concept of a "wireless IP router" has not been addressed so far. We examine the limitations of the IEEE 802.11 MAC protocol in supporting a low-latency and high-throughput IP datapath comprising multiple wireless LAN hops. We first propose a wireless IP forwarding architecture that uses MPLS with modifications to 802.11 MAC to significantly improve packet forwarding …


Security Remarks On A Group Signature Scheme With Member Deletion, Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng Oct 2003

Security Remarks On A Group Signature Scheme With Member Deletion, Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

A group signature scheme allows a group member of a given group to sign messages on behalf of the group in an anonymous and unlinkable fashion. In case of a dispute, however, a designated group manager can reveal the signer of a valid group signature. Based on the Camenisch-Michels group signature scheme, Kim, Lim and Lee proposed the first group signature scheme with a member deletion procedure at ICISC 2000. Their scheme is very efficient in both communication and computation aspects. Unfortunately, their scheme is insecure. In this paper, we first identify an effective way that allows any verifier to …


Variations Of Diffie-Hellman Problem, Feng Bao, Robert H. Deng, Huafei Zhu Oct 2003

Variations Of Diffie-Hellman Problem, Feng Bao, Robert H. Deng, Huafei Zhu

Research Collection School Of Computing and Information Systems

This paper studies various computational and decisional Diffie-Hellman problems by providing reductions among them in the high granularity setting. We show that all three variations of computational Diffie-Hellman problem: square Diffie-Hellman problem, inverse Diffie-Hellman problem and divisible Diffie-Hellman problem, are equivalent with optimal reduction. Also, we are considering variations of the decisional Diffie-Hellman problem in single sample and polynomial samples settings, and we are able to show that all variations are equivalent except for the argument DDH ⇐ SDDH. We are not able to prove or disprove this statement, thus leave an interesting open problem. Keywords: Diffie-Hellman problem, Square Diffie-Hellman …


Ssm: Fast Construction Of The Optimized Segment Support Map, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim Sep 2003

Ssm: Fast Construction Of The Optimized Segment Support Map, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Computing the frequency of a pattern is one of the key operations in data mining algorithms. Recently, the Optimized Segment Support Map (OSSM) was introduced as a simple but powerful way of speeding up any form of frequency counting satisfying the monotonicity condition. However, the construction cost to obtain the ideal OSSM is high, and makes it less attractive in practice. In this paper, we propose the FSSM, a novel algorithm that constructs the OSSM quickly using a FP-Tree. Given a user-defined segment size, the FSSM is able to construct the OSSM at a fraction of the time required by …


On Mining Group Patterns Of Mobile Users, Yida Wang, Ee Peng Lim, San-Yih Hwang Sep 2003

On Mining Group Patterns Of Mobile Users, Yida Wang, Ee Peng Lim, San-Yih Hwang

Research Collection School Of Computing and Information Systems

In this paper, we present a group pattern mining approach to derive the grouping information of mobile device users based on the spatio-temporal distances among them. Group patterns of users are determined by a distance threshold and a minimum duration. To discover group patterns, we propose the AGP and VG-growth algorithms that are derived from the Apriori and FP-growth algorithms respectively. We further evaluate the efficiencies of these two algorithms using synthetically generated user movement data.


Solving Multi-Objective Multi-Constrained Optimization Problems Using Hybrid Ants System And Tabu Search, Hoong Chuin Lau, Min Kwang Lim, Wee Chong Wan, Hui Wang, Xiaotao Wu Aug 2003

Solving Multi-Objective Multi-Constrained Optimization Problems Using Hybrid Ants System And Tabu Search, Hoong Chuin Lau, Min Kwang Lim, Wee Chong Wan, Hui Wang, Xiaotao Wu

Research Collection School Of Computing and Information Systems

Many real-world optimization problems today are multi-objective multi-constraint generalizations of NP-hard problems. A classic case we study in this paper is the Inventory Routing Problem with Time Windows (IRPTW). IRPTW considers inventory costs across multiple instances of Vehicle Routing Problem with Time Windows (VRPTW). The latter is in turn extended with time-windows constraints from the Vehicle Routing Problem (VRP), which is extended with optimal fleet size objective from the single-objective Traveling Salesman Problem (TSP). While single-objective problems like TSP are solved effectively using meta-heuristics, it is not obvious how to cope with the increasing complexity systematically as the problem is …


Towards A Role-Based Metadata Scheme For Educational Digital Libraries: A Case Study In Singapore, Dian Melati Md Ismail, Ming Yin, Yin-Leng Theng, Dion Hoe-Lian Goh, Ee Peng Lim Aug 2003

Towards A Role-Based Metadata Scheme For Educational Digital Libraries: A Case Study In Singapore, Dian Melati Md Ismail, Ming Yin, Yin-Leng Theng, Dion Hoe-Lian Goh, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In this paper, we describe the development of an appropriate metadata scheme for GeogDL, a Web-based digital library application containing past-year examination resources for students taking a Singapore national examination in geography. The new metadata scheme was developed from established metadata schemes on education and e-learning. Initial evaluation showed that a role-based approach would be more viable, adapting to the different roles of teachers/educators and librarians contributing geography resources to GeogDL. The paper concludes with concrete implementation of the role-based metadata schema for GeogDL.


A Generic Object-Oriented Tabu Search Framework, Hoong Chuin Lau, Wee Chong Wan, Xiaomin Jia Aug 2003

A Generic Object-Oriented Tabu Search Framework, Hoong Chuin Lau, Wee Chong Wan, Xiaomin Jia

Research Collection School Of Computing and Information Systems

Presently, most tabu search designers devise their applications without considering the potential of design and code reuse, which consequently prolong the development of subsequent applications. In this paper, we propose a software solution known as Tabu Search Framework (TSF), which is a generic C++ software framework for tabu search implementation. The framework excels in code recycling through the use of a welldesigned set of generic abstract classes that clearly define their collaborative roles in the algorithm. Additionally, the framework incorporates a centralized process and control mechanism that enhances the search with intelligence. This results in a generic framework that is …


Performance Sensitivity And Fairness Of Ecn-Aware 'Modified Tcp', Archan Misra, Teunis Ott Aug 2003

Performance Sensitivity And Fairness Of Ecn-Aware 'Modified Tcp', Archan Misra, Teunis Ott

Research Collection School Of Computing and Information Systems

The paper discusses how Explicit Congestion Notification (ECN) can be used to devise a congestion control mechanism for the Internet, which is more rapidly reactive and allows best-effort flows to rapidly adjust to fluctuations in available capacity. Our ECN-mod protocol involves simple modifications to TCP behavior and leverages more aggressive marking-based router feedback.Simulations show that ECN-mod is better than TCP NewReno even for Web-style intermittent traffic sources, and makes the link utilization significantly less sensitive to the variation in the number of active flows. Simulations also show that, while ECN-mod flows obtain a larger portion of the available capacity than …


Trifocal Morphing, Angus M. K. Siu, Ada S. K. Wan, Rynson W. H. Lau, Chong-Wah Ngo Jul 2003

Trifocal Morphing, Angus M. K. Siu, Ada S. K. Wan, Rynson W. H. Lau, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Image morphing allows smooth transition between 2D images. However, one of the limitations of existing image morphing techniques is the lack of interaction - the viewpoints of the interpolated images are restrained to the line joining the optical centers of the source and the destination images. Another limitation of existing image morphing techniques is that shape warping often causes distortion due to barycentric mapping. In this paper, we present our trifocal morphing technique to address these problems. The new technique allows a user to change the viewpoint of the output images, i.e., increasing the degrees of freedom of interaction, and …


Video Clip Retrieval By Maximal Matching And Optimal Matching In Graph Theory, Yu-Xin Peng, Chong-Wah Ngo, Qing-Jie Dong, Zong-Ming Guo, Jian-Guo Xiao Jul 2003

Video Clip Retrieval By Maximal Matching And Optimal Matching In Graph Theory, Yu-Xin Peng, Chong-Wah Ngo, Qing-Jie Dong, Zong-Ming Guo, Jian-Guo Xiao

Research Collection School Of Computing and Information Systems

In this paper, a novel approach for automatic matching, ranking and retrieval of video clips is proposed. Motivated by the maximal and optimal matching theories in graph analysis, a new similarity measure of video clips is defined based on the representation and modeling of bipartite graph. Four different factors: visual similarity, granularity, interference and temporal order of shots are taken into consideration for similarity ranking. These factors are progressively analyzed in the proposed approach. Maximal matching utilizes the granularity factor to efficiently filter false matches, while optimal matching takes into account the visual, granularity and interference factors for similarity measure. …