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Information Recovery In A Study With Surrogate Endpoints, Song Xi Chen, Denis H. Y. Leung, Jing Qin Dec 2003

Information Recovery In A Study With Surrogate Endpoints, Song Xi Chen, Denis H. Y. Leung, Jing Qin

Research Collection School Of Economics

Recently, there has been a lot of interest in statistical methods for analyzing data with surrogate endpoints. In this article, we consider parameter estimation from a model that relates a variable Y to a set of covariates, X, in the presence of a surrogate, S. We assume that the data are made up of two random samples from the population, a validation set where (Y, X, S) are observed on every subject and a nonvalidation set where only (X, S) are measured. We show how information from the nonvalidation set can be incorporated to improve upon estimation of a parameter …

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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, …

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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" …

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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.

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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 …

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Pricing And Qos Of Information Services In A Competitive Market, Zhen Liu, Laura Wynter, Cathy Xia Nov 2003

Pricing And Qos Of Information Services In A Competitive Market, Zhen Liu, Laura Wynter, Cathy Xia

Research Collection School Of Computing and Information Systems

Design of e-commerce services that are competitive in a quickly responding market requires the analyses of prices and price structures. We develop a general model of an e-commerce market that allows us to analyze optimal price structures, both flat and usage-based. Based on the price structure of a major web hosting provider, we consider single-tier and two-tier (burst-rate) pricing, and our result suggests that the more complex two-tier structure may not be worth the marketing effort, as the firm's equilibrium profits will not increase through the use of this structure. An essential feature of our approach is that we model …

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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 …

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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.

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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.

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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.

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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 …

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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 …

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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 …

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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 …

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Incorporating Diversification Into Risk Management, Mitchell Craig Warachka, A. Purnanandam, Y. Zhao, W.T. Ziemba Oct 2003

Incorporating Diversification Into Risk Management, Mitchell Craig Warachka, A. Purnanandam, Y. Zhao, W.T. Ziemba

Research Collection Lee Kong Chian School Of Business

No abstract provided.

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A Note On The Numerical Solution Of High-Order Differential Equations, Y. Wang, Yibao Zhao, G. W. Wei Oct 2003

A Note On The Numerical Solution Of High-Order Differential Equations, Y. Wang, Yibao Zhao, G. W. Wei

Research Collection Lee Kong Chian School Of Business

Numerical solution of high-order differential equations with multi-boundary conditions is discussed in this paper. Motivated by the discrete singular convolution algorithm, the use of fictitious points as additional unknowns is proposed in the implementation of locally supported Lagrange polynomials. The proposed method can be regarded as a local adaptive differential quadrature method. Two examples, an eigenvalue problem and a boundary-value problem, which are governed by a sixth-order differential equation and an eighth-order differential equation, respectively, are employed to illustrate the proposed method.

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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 …

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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 …

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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 …

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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 …

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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, …

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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.

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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.

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Capacitated Network Revenue Management Through Shadow Pricing, Mustapha Bouhtou, Madiagne Diallo, Laura Wynter Sep 2003

Capacitated Network Revenue Management Through Shadow Pricing, Mustapha Bouhtou, Madiagne Diallo, Laura Wynter

Research Collection School Of Computing and Information Systems

In this paper, we analyze a method that links Lagrange multipliers from a resource allocation problem to the problem of revenue or profit maximization. This technique, first proposed in the transportation science literature by [7] has important implications for telecommunication network pricing. Indeed, the framework provides a generalization of telecommunication resource allocation/shadow price-based schemes such as those of [6] and [9], in that it permits the optimization of the shadow prices themselves, through a computationally simple procedure. We analyze the extent to which revenue can be maximized on a network that uses shadow-price-based prices, and how to deal with cases …

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E-Ducation, J. Erickson, Keng Siau Sep 2003

E-Ducation, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

Most educators are convinced Internet technology will sharply alter the educational landscape of the future, but considerable uncertainly still exists as to exactly how the classroom will evolve over the next decade. Many of the relevant technologies in development are a direct result of the Internet2 Project [1], a collaboration of more than 200 universities working closely with private industry and the National Science Foundation to build and promote an advanced network using state-of-the-art technology and applications. But how the classroom evolves depends not only on advanced Internet2 technologies, which are discussed later in the article, but also on issues …

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Aggregated Causal Maps: An Approach To Elicit And Aggregate The Knowledge Of Multiple Experts, S. Nadkarni, Fiona Fui-Hoon Nah Sep 2003

Aggregated Causal Maps: An Approach To Elicit And Aggregate The Knowledge Of Multiple Experts, S. Nadkarni, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

This paper presents a systematic procedure to elicit and aggregate the knowledge of multiple individual experts and represent it in the form of an Aggregated Causal Map (ACM). This procedure differs from existing methods in two ways. First, unlike other methods, this method does not rely on group interaction in eliciting knowledge of multiple experts, and, therefore, is not fraught with biases associated with group dynamics. Second, this method uses both the idiographic and nomothetic approaches while existing methods focus on nomothetic approaches to knowledge elicitation. We draw on the strengths of both approaches by using the idiographic approach to …

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Estimating Credit Risk Premia, Kian Guan Lim Sep 2003

Estimating Credit Risk Premia, Kian Guan Lim

Research Collection Lee Kong Chian School Of Business

This paper investigates the nature of the credit risk premium adjustments in the Jarrow-Lando-Turnbull model of credit risk spreads. The adjustments relate the equivalent martingale measures to the empirical measures of unconditional transition probabilities. We provide a modi ed version of the risk adjustment that allows a linear partition of the credit spread into an unconditional default component, a recovery component, and the risk premium adjustment. The risk adjustments are related to conditional default risk, illiquidity risk, and other factors not related to recovery e ects. The log-transform of these risk adjustments can be speci ed as linear regressions on …

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Design Of Antiresonant-Reflecting Optical Waveguide-Type Vertical-Coupled Surface-Emitting Lasers Using Transfer Matrix Method, Chyng Wen Tee, C. C. Tan, S. F. Yu Sep 2003

Design Of Antiresonant-Reflecting Optical Waveguide-Type Vertical-Coupled Surface-Emitting Lasers Using Transfer Matrix Method, Chyng Wen Tee, C. C. Tan, S. F. Yu

Research Collection Lee Kong Chian School Of Business

A simple transfer matrix method is proposed to calculate the radiation losses of a cylindrical antiresonant-reflecting optical waveguide (ARROW). It is found that the planar approximation underestimates the radiation losses but overestimates the design tolerance of the ARROW-type vertical-cavity surface-emitting lasers (VCSELs). An iteration technique, which is incorporated with the transfer matrix method, is also developed to design ARROW-type VCSELs for minimum radiation losses in a more effective manner.

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Asymptotic Dynamics And Value-At-Risk Of Large Diversified Portfolios In A Jump-Diffusion Market, Kian Guan Lim, Xiaoqing Liu, Kai Chong Tsui Sep 2003

Asymptotic Dynamics And Value-At-Risk Of Large Diversified Portfolios In A Jump-Diffusion Market, Kian Guan Lim, Xiaoqing Liu, Kai Chong Tsui

Research Collection Lee Kong Chian School Of Business

This paper studies the modelling of large diversi ed portfolios in a nancial market with jump-di usion risks. The portfolios considered include three categories: equal money-weighted portfolios, risk minimizing portfolios, and market indices. Reduced-form dynamics driven jointly by one Brownian Motion and one Poisson process are derived for the asymptotics of such portfolios. We prove that derivatives written on a portfolio can be priced by treating the asymptotic dynamics as the underlying process if the number of assets in the portfolio is su ciently large. Analytical and Monte Carlo Value-at-Risk (VaR) can be computed for the portfolios based on their …

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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.

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