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Articles 7111 - 7140 of 7446

Full-Text Articles in Physical Sciences and Mathematics

Idmp: An Intradomain Mobility Management Protocol For Next-Generation Wireless Networks, Subir Das, Anthony Mcauley, Ashutosh Dutta, Archan Misra, Sajal K. Das Jun 2002

Idmp: An Intradomain Mobility Management Protocol For Next-Generation Wireless Networks, Subir Das, Anthony Mcauley, Ashutosh Dutta, Archan Misra, Sajal K. Das

Research Collection School Of Computing and Information Systems

This paper describes a lightweight Intra-domain Management Protocol (IDMP) for managing mobility within a domain, commonly known as micro-mobility management, for next generation wireless networks. IDMP is modular and simple because it leverages existing protocols, such as Mobile IP or SIP (Session Initiated Protocol) as global mobility management, for locating roaming nodes. Unlike other proposed intra-domain mobility management schemes, IDMP uses two dynamically autoconfigured care-of addresses (CoAs) for routing the packets destined to mobile nodes. The global care-of address (GCoA) is relatively stable and identifies the mobile node’s attachment to the current domain, while the local care-of address (LCoA) changes …

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Minimum Energy Paths For Reliable Communication In Multi-Hop Wireless Networks, Suman Banerjee, Archan Misra Jun 2002

Minimum Energy Paths For Reliable Communication In Multi-Hop Wireless Networks, Suman Banerjee, Archan Misra

Research Collection School Of Computing and Information Systems

Current algorithms for minimum-energy routing in wireless networks typically select minimum-cost multi-hop paths. In scenarios where the transmission power is fixed, each link has the same cost and the minimum-hop path is selected. In situations where the transmission power can be varied with the distance of the link, the link cost is higher for longer hops; the energy-aware routing algorithms select a path with a large number of small-distance hops. In this paper, we argue that such a formulation based solely on the energy spent in a single transmission is misleading --- the proper metric should include the total energy …

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Energy Efficiency And Throughput For Tcp Traffic In Multi-Hop Wireless Networks, Sorav Bansal, Rajeev Gupta, Rajeev Shorey, Imran Ali, Ashu Razdan, Archan Misra Jun 2002

Energy Efficiency And Throughput For Tcp Traffic In Multi-Hop Wireless Networks, Sorav Bansal, Rajeev Gupta, Rajeev Shorey, Imran Ali, Ashu Razdan, 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 session 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, …

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Microscopic Chaos And Gaussian Diffusion Processes, L. Y. Chew, Christopher Ting May 2002

Microscopic Chaos And Gaussian Diffusion Processes, L. Y. Chew, Christopher Ting

Research Collection Lee Kong Chian School Of Business

In this paper, we construct and analyze a prototypical model of microscopic chaos. In particular, we extend the results of Beck and Shimizu to the case where the microscopic time scale r is no longer small. The upshot is that a non-Ornstein-Uhlenbeck deterministic process can generate a Gaussian diffusion process.

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Personalized Information Management For Web Intelligence, Ah-Hwee Tan May 2002

Personalized Information Management For Web Intelligence, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Web intelligence can be defined as the process of scanning and tracking information on the World Wide Web so as to gain competitive advantages. This paper describes a system known as Flexible Organizer for Competitive Intelligence (FOCI) that transforms raw URLs returned by internet search engines into personalized information portfolios. FOCI builds information portfolios by gathering and organizing online information according to a user's needs and preferences. Through a novel method called User-Configurable Clustering, a user can personalize his/her portfolios in terms of the content as well as the information structure. The personalized portfolios can then be used to track …

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A Case For Analytical Customer Relationship Management, Jaideep Srivastava, Jau-Hwang Wang, Ee Peng Lim, San-Yih Hwang May 2002

A Case For Analytical Customer Relationship Management, Jaideep Srivastava, Jau-Hwang Wang, Ee Peng Lim, San-Yih Hwang

Research Collection School Of Computing and Information Systems

This paper describes how data analytics can be used to make various CRM functions like customer segmentation, communication targeting, retention, and loyalty much more effective. Also briefly describe the key technologies needed to implement analytical CRM, and are the organizational issues that must be carefully handled to make CRM a reality.

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Proteome Database Of Hepatocellular Carcinoma., Cynthia Liang, Jason Neo, Siaw Ling Lo, Gek San Tan, Teck Keong Seow, Maxey Chung May 2002

Proteome Database Of Hepatocellular Carcinoma., Cynthia Liang, Jason Neo, Siaw Ling Lo, Gek San Tan, Teck Keong Seow, Maxey Chung

Research Collection School Of Computing and Information Systems

Hepatocellular carcinoma (HCC or hepatoma) is the most common primary cancer of the liver. Persistent viral infection by the hepatic B or C virus is probably the most important cause of HCC worldwide. It is responsible for approximately one million deaths each year, predominantly in the underdeveloped and developing countries, but its incidence is also on the rise in the developed countries. For most patients suffering from HCC, long-term survival is rare, as they are presented late and are often unsuitable for curative treatment. Thus there is great interest to identify novel HCC diagnostic markers for early detection of the …

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Mining Relationship Graphs For Effective Business Objectives, Kok-Leong Ong, Ee Peng Lim, Wee-Keong Ng May 2002

Mining Relationship Graphs For Effective Business Objectives, Kok-Leong Ong, Ee Peng Lim, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

Modern organization has two types of customer profiles: active and passive. Active customers contribute to the business goals of an organization, while passive customers are potential candidates that can be converted to active ones. Existing KDD techniques focused mainly on past data generated by active customers. The insights discovered apply well to active ones but may scale poorly with passive customers. This is because there is no attempt to generate know-how to convert passive customers into active ones. We propose an algorithm to discover relationship graphs using both types of profile. Using relationship graphs, an organization can be more effective …

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Product Schema Integration For Electronic Commerce: A Synonym Comparison Approach, Guanghao Yan, Wee-Keong Ng, Ee Peng Lim May 2002

Product Schema Integration For Electronic Commerce: A Synonym Comparison Approach, Guanghao Yan, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In any electronic commerce system, the heterogeneity of product descriptions is a critical impediment to efficient business information exchange. In the ABECOS electronic commerce system, buyer agents, seller agents, and directory agents liaise with one another in e-commerce activities. Only when agents have a common ontology of product descriptions (also called product schemas) are they able to interact seamlessly in e-commerce activities. This gives rise to the product schema integration problem (PSI); the problem of integrating heterogeneous schemas of a certain product into one globally compatible schema. We adopt an integration approach based on product attribute synonyms. We give a …

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Driving In Traffic: Short-Range Sensing For Urban Collision Avoidance, Chuck Thorpe, Dave Duggins, Jay Gowdy, Rob Maclaughlin, Christoph Mertz, Mel Siegel, Arne Suppe, Bob Wang, Teruko Yata Apr 2002

Driving In Traffic: Short-Range Sensing For Urban Collision Avoidance, Chuck Thorpe, Dave Duggins, Jay Gowdy, Rob Maclaughlin, Christoph Mertz, Mel Siegel, Arne Suppe, Bob Wang, Teruko Yata

Research Collection School Of Computing and Information Systems

Intelligent vehicles are beginning to appear on the market, but so far their sensing and warning functions only work on the open road. Functions such as runoff-road warning or adaptive cruise control are designed for the uncluttered environments of open highways. We are working on the much more difficult problem of sensing and driver interfaces for driving in urban areas. We need to sense cars and pedestrians and curbs and fire plugs and bicycles and lamp posts; we need to predict the paths of our own vehicle and of other moving objects; and we need to decide when to issue …

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A New Approach For Weighted Constraint Satisfaction, Hoong Chuin Lau Apr 2002

A New Approach For Weighted Constraint Satisfaction, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider the Weighted Constraint Satisfaction Problem which is an important problem in Artificial Intelligence. Given a set of variables, their domains and a set of constraints between variables, our goal is to obtain an assignment of the variables to domain values such that the weighted sum of satisfied constraints is maximized. In this paper, we present a new approach based on randomized rounding of semidefinite programming relaxation. Besides having provable worst-case bounds for domain sizes 2 and 3, our algorithm is simple and efficient in practice, and produces better solutions than some other polynomial-time algorithms such as greedy and …

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Multi-Level Modeling Of Software On Hardware In Concurrent Computation, Joann M. Paul, Arne Suppe, Henele I. Adams, Donald E. Thomas Apr 2002

Multi-Level Modeling Of Software On Hardware In Concurrent Computation, Joann M. Paul, Arne Suppe, Henele I. Adams, Donald E. Thomas

Research Collection School Of Computing and Information Systems

The fundamental modeling differences between hardware and software modeling can be thought of as reasoning about connectedness vs. reasoning about interleaved (shared) access to resources. A natural design hierarchy for physical systems is component-based because of the existence of a consistent basis for interconnect between design levels. However, performance modeling and design of concurrent, programmable systems require new ways of thinking about what it means to abstract detail, add detail and partition a model of software executing on hardware. We motivate frequency interleaving (FI) as a common simulation foundation for these systems because it resolves flow and partitioning with software …

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Plate Vibration Under Irregular Internal Supports, Yibao Zhao, G. W. Wei, Y. Xiang Mar 2002

Plate Vibration Under Irregular Internal Supports, Yibao Zhao, G. W. Wei, Y. Xiang

Research Collection Lee Kong Chian School Of Business

This paper studies the problem of plate vibration under complex and irregular internal support conditions. Such a problem has its widely spread industrial applications and has not been addressed in the literature yet, partially due to the numerical difficulties. A novel computational method, discrete singular convolution (DSC), is introduced for solving this problem. The DSC algorithm exhibits controllable accuracy for approximations and shows excellent flexibility in handling complex geometries, boundary conditions and internal support conditions. Convergence and comparison studies are carried out to check the validity and accuracy of the DSC method. Case studies are considered to the combination of …

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B2b E-Commerce Revisited: Leading Perspectives On The Key Issues And Research Directions, Qizhi Dai, Robert J. Kauffman Mar 2002

B2b E-Commerce Revisited: Leading Perspectives On The Key Issues And Research Directions, Qizhi Dai, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

The application of Internet technologies for the conduct of interfirm business transactions has given rise to a boom in business-to-business (B2B) electronic commerce. Yet, although there are many success stories that have been reported over the past several years, the progress of B2B e-commerce has been hindered by unanticipated technical, organizational, economic and legal challenges that diminish value. In this article, we report on a series of interviews with leading academic researchers and industry senior managers who are in a unique position to make sense of key issues and offer useful insights. The respondents provide their views on the efficacy …

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Mrpc: Maximizing Network Lifetime For Reliable Routing In Wireless Environments, Archan Misra, Suman Banerjee Mar 2002

Mrpc: Maximizing Network Lifetime For Reliable Routing In Wireless Environments, Archan Misra, Suman Banerjee

Research Collection School Of Computing and Information Systems

We propose MRPC, a new power-aware routing algorithm for energy-efficient routing that increases the operational lifetime of multi-hop wireless networks. In contrast to conventional power-aware algorithms, MRPC identifies the capacity of a node not just by its residual battery energy, but also by the expected energy spent in reliably forwarding a packet over a specific link. Such a formulation better captures scenarios where link transmission costs also depend on physical distances between nodes and the link error rates. Using a max-min formulation, MRPC selects the path that has the largest packet capacity at the 'critical' node (the one with the …

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An Intelligent Middleware For Linear Correlation Discovery, Cecil Chua, Roger Hsiang-Li Chiang, Ee Peng Lim Mar 2002

An Intelligent Middleware For Linear Correlation Discovery, Cecil Chua, Roger Hsiang-Li Chiang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Although it is widely accepted that research from data mining, knowledge discovery, and data warehousing should be synthesized, little research addresses the integration of existing data management and analysis software. We develop an intelligent middleware that facilitates linear correlation discovery, the discovery of associations between attributes and attribute groups. This middleware integrates data management and data analysis tools to improve traditional data analysis in three perspectives: (1) identify appropriate linear correlation functions to perform based on the semantics of a data set; (2) execute appropriate functions contained in the data analysis packages; and (3) derive useful knowledge from data analysis.

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Idmp-Based Fast Handoffs And Paging In Ip-Based 4g Mobile Networks, Archan Misra, Subir Das, Anthony Mcauley, Sajal K. Das Mar 2002

Idmp-Based Fast Handoffs And Paging In Ip-Based 4g Mobile Networks, Archan Misra, Subir Das, Anthony Mcauley, Sajal K. Das

Research Collection School Of Computing and Information Systems

We consider the use of our previously proposed Intra-Domain Mobility Management Protocol (IDMP) in fourth-generation mobile networks. On evaluating the heterogeneous access technologies, cellular layouts, and application characteristics of 4G environments, we realize a need to reduce both handoff latency and the frequency of mobility-related signaling. We first present IDMP's fast intradomain handoff mechanism that uses a duration-limited proactive packet multicasting solution. We quantify the expected buffering requirements of our proposed multicasting scheme for typical 4G network characteristics and compare it with alternative IP-based fast handoff solutions. We also present a paging scheme under IDMP that replicates the current cellular …

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Smil Vs Mpeg-4 Bifs, Lai-Tee Cheok, Alexandros Eleftheriadis Feb 2002

Smil Vs Mpeg-4 Bifs, Lai-Tee Cheok, Alexandros Eleftheriadis

Research Collection School Of Computing and Information Systems

We present the results of a comparative analysis between the Synchronized Multimedia Integration Language (SMIL) and MPEG-4 BInary Format for Scenes (BIFS). SMIL is a language developed by the W3C consortium for expressing media synchronization among objects of various media types. MPEG-4 BIFS is the scene description scheme of MPEG-4, an international standard for communicating interactive audiovisual scenes. They are both facilities for representing and synchronizing multimedia content, and have a wide range of support for interactivity, animation and object composition features, etc. We compare their scope and purposes, the level of support for the multimedia features and investigate the …

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Experimenting With Server-Aided Signatures, Xuhua Ding, D. Mozzacchi, Gene Tsudik Feb 2002

Experimenting With Server-Aided Signatures, Xuhua Ding, D. Mozzacchi, Gene Tsudik

Research Collection School Of Computing and Information Systems

This paper explores practical and conceptual implications of using Server-Aided Signatures (SAS). SAS is a signature method that relies on partiallytrusted servers for generating public key signatures for regular users. Besides its two primary goals of 1) aiding small, resource-limited devices in computing heavy-weight (normally expensive) digital signatures and 2) fast certificate revocation, SAS also o#ers signature causality and has some interesting features such as built-in attack detection for users and DoS resistance for servers.

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Using Real Options Analysis For Evaluating Uncertain Investments In Information Technology: Insights From The Icis 2001 Debate, Paul P. Tallon, Robert J. Kauffman, Henry C. Lucas, Andrew B. Whinston, Kevin Zhu Jan 2002

Using Real Options Analysis For Evaluating Uncertain Investments In Information Technology: Insights From The Icis 2001 Debate, Paul P. Tallon, Robert J. Kauffman, Henry C. Lucas, Andrew B. Whinston, Kevin Zhu

Research Collection School Of Computing and Information Systems

Business and information systems (IS) executives continue to grapple with issues of risk and uncertainty in evaluating investments in information technology (IT). Despite the use of net present value (NPV) and other investment appraisal techniques, executives are often forced to rely on instinct when finalizing IT investment decisions. Recognizing the shortcomings of NPV, real options analysis has been suggested as an alternative approach, one that considers the risks associated with an investment while recognizing the ability of corporations to defer an investment until a later period or to make a partial investment instead. Responding to a growing interest in real …

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Anatomy Of A Coupling Query In A Web Warehouse, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim Jan 2002

Anatomy Of A Coupling Query In A Web Warehouse, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

To populate a data warehouse specifically designed for Web data, i.e. web warehouse, it is imperative to harness relevant documents from the Web. In this paper, we describe a query mechanism called coupling query to glean relevant Web data in the context of our web warehousing system called Warehouse Of Web Data (WHOWEDA). Coupling query may be used for querying both HTML and XML documents. Some of the important features of our query mechanism are ability to query metadata, content, internal and external (hyperlink) structure of Web documents based on partial knowledge, ability to express constraints on tag attributes and …

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Enhancing Profiles For Anomaly Detection Using Time Granularities, Yingjiu Li, Ningning Wu, X. Sean Wang, Sushil Jajodia Jan 2002

Enhancing Profiles For Anomaly Detection Using Time Granularities, Yingjiu Li, Ningning Wu, X. Sean Wang, Sushil Jajodia

Research Collection School Of Computing and Information Systems

Recently, association rules have been used to generate profiles of normal behavior for anomaly detection. However, the time factor (especially in terms of multiple time granularities) has not been utilized extensively in generation of these profiles. In reality, user behavior during different time intervals may be very different. For example, the normal number and duration of FTP connections may vary from working hours to midnight, from business day to weekend or holiday. Furthermore, these variations may depend on the day of the month or the week. This paper proposes to build profiles using temporal association rules in terms of multiple …

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Discrete Singular Convolution For The Prediction Of High Frequency Vibration Of Plates, Yibao Zhao, G. W. Wei, Y. Xiang Dec 2001

Discrete Singular Convolution For The Prediction Of High Frequency Vibration Of Plates, Yibao Zhao, G. W. Wei, Y. Xiang

Research Collection Lee Kong Chian School Of Business

Theoretical analysis of high frequency vibrations is indispensable in a variety of engineering designs. Much effort has been made on this subject in the past few decades. However, there is no single technique which can be applied with confidence to various engineering structures for high frequency predictions at present. This paper introduces a novel computational approach, the discrete singular convolution (DSC) algorithm, for high frequency vibration analysis of plate structures. Square plates with six distinct boundary conditions are considered. To validate the proposed method, a completely independent approach, the Levy method, is employed to provide exact solutions for a comparison. …

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Automated Online News Classification With Personalization, Chee-Hong Chan, Aixin Sun, Ee Peng Lim Dec 2001

Automated Online News Classification With Personalization, Chee-Hong Chan, Aixin Sun, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Classification of online news, in the past, has often been done manually. In our proposed Categorizor system, we have experimented an automated approach to classify online news using the Support Vector Machine (SVM). SVM has been shown to deliver good classification results when ample training documents are given. In our research, we have applied SVM to personalized classification of online news.

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Privacy Protection For Transactions Of Digital Goods, Feng Bao, Robert H. Deng Nov 2001

Privacy Protection For Transactions Of Digital Goods, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

In this paper we study the problem of how to protect users’ privacy in web transactions of digital goods. In particular, we introduce a system which allows a user to disclose his/her identity information (such as user account or credit card number) to a web site in exchange for a digital item, but prevents the web site from learning which specific item the user intends to obtain. The problem concerned here is orthogonal to the problem of anonymous transactions [RSG98], [RR98] but commensurate with the general problem of PIR (private information retrieval) [CGK95]

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Pickup And Delivery Problem With Time Windows: Algorithms And Test Case Generation, Hoong Chuin Lau, Zhe Liang Nov 2001

Pickup And Delivery Problem With Time Windows: Algorithms And Test Case Generation, Hoong Chuin Lau, Zhe Liang

Research Collection School Of Computing and Information Systems

In the pickup and delivery problem with time windows (PDPTW), vehicles have to transport loads from origins to destinations respecting capacity and time constraints. In this paper, we present a two-phase method to solve the PDPTW. In the first phase, we apply a novel construction heuristics to generate an initial solution. In the second phase, a tabu search method is proposed to improve the solution. Another contribution of this paper is a strategy to generate good problem instances and benchmarking solutions for PDPTW, based on Solomon's benchmark test cases for VRPTW. Experimental results show that our approach yields very good …

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Hierarchical Text Classification And Evaluation, Aixin Sun, Ee Peng Lim Nov 2001

Hierarchical Text Classification And Evaluation, Aixin Sun, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Hierarchical Classification refers to assigning of one or more suitable categories from a hierarchical category space to a document. While previous work in hierarchical classification focused on virtual category trees where documents are assigned only to the leaf categories, we propose atop-down level-based classification method that can classify documents to both leaf and internal categories. As the standard performance measures assume independence between categories, they have not considered the documents incorrectly classified into categories that are similar or not far from the correct ones in the category tree. We therefore propose the Category-Similarity Measures and Distance-Based Measures to consider the …

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Mining Multi-Level Rules With Recurrent Items Using Fp'-Tree, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim Oct 2001

Mining Multi-Level Rules With Recurrent Items Using Fp'-Tree, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Association rule mining has received broad research in the academic and wide application in the real world. As a result, many variations exist and one such variant is the mining of multi-level rules. The mining of multi-level rules has proved to be useful in discovering important knowledge that conventional algorithms such as Apriori, SETM, DIC etc., miss. However, existing techniques for mining multi-level rules have failed to take into account the recurrence relationship that can occur in a transaction during the translation of an atomic item to a higher level representation. As a result, rules containing recurrent items go unnoticed. …

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Jointly Coordinating Ecn And Tcp For Rapid Adaptation To Varying Bandwidth, Archan Misra, Teunis Ott Oct 2001

Jointly Coordinating Ecn And Tcp For Rapid Adaptation To Varying Bandwidth, Archan Misra, Teunis Ott

Research Collection School Of Computing and Information Systems

The introduction of service differentiation in the Internet implies that the residual bandwidth available to best-effort traffic becomes highly variable. We explore the design of a rapidly-reactive congestion control framework, where the ECN-aware best-effort flows aggressively go after any unused capacity. By making routers mark packets in a much more aggressive manner, we are able to achieve fast backoff in the network without resorting to the TCP's current drastic step of halving the congestion window. Simulations indicate that our ECN-mod protocol is better than ECN-NewReno in exploiting rapid variations in the available bandwidth. Moreover, the milder backoff policy of ECN-mod …

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Hierarchical Mobility Management For Voip Traffic, Archan Misra, Subir Das, Anthony J. Mcauley Oct 2001

Hierarchical Mobility Management For Voip Traffic, Archan Misra, Subir Das, Anthony J. Mcauley

Research Collection School Of Computing and Information Systems

A hierarchical IP-based mobility management mechanism is proposed for VoIP applications. The suggested mechanism uses the DMA (dynamic mobility agent) architecture, based on IDMP (intra-domain mobility management protocol), for managing intra-domain mobility and the dynamic binding mechanism of SIP (session initiation protocol) for managing global mobility. This combination of network and application layer mobility management reduces the global signaling load, provides fast handoff for ongoing conversations, enables efficient global transport and supports IP-layer paging.

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