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Articles 8671 - 8700 of 9440

Full-Text Articles in Physical Sciences and Mathematics

Accurately Extracting Coherent Relevant Passages Using Hidden Markov Models, Jing Jiang, Chengxiang Zhai Nov 2005

Accurately Extracting Coherent Relevant Passages Using Hidden Markov Models, Jing Jiang, Chengxiang Zhai

Research Collection School Of Computing and Information Systems

In this paper, we present a principled method for accurately extracting coherent relevant passages of variable lengths using HMMs. We show that with appropriate parameter estimation, the HMM method outperforms a number of strong baseline methods on two data sets.

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A Threshold-Based Algorithm For Continuous Monitoring Of K Nearest Neighbors, Kyriakos Mouratidis, Dimitris Papadias, Spiridon Bakiras, Yufei Tao Nov 2005

A Threshold-Based Algorithm For Continuous Monitoring Of K Nearest Neighbors, Kyriakos Mouratidis, Dimitris Papadias, Spiridon Bakiras, Yufei Tao

Research Collection School Of Computing and Information Systems

Assume a set of moving objects and a central server that monitors their positions over time, while processing continuous nearest neighbor queries from geographically distributed clients. In order to always report up-to-date results, the server could constantly obtain the most recent position of all objects. However, this naïve solution requires the transmission of a large number of rapid data streams corresponding to location updates. Intuitively, current information is necessary only for objects that may influence some query result (i.e., they may be included in the nearest neighbor set of some client). Motivated by this observation, we present a threshold-based algorithm …

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Query Processing In Spatial Databases Containing Obstacles, Jun Zhang, Dimitris Papadias, Kyriakos Mouratidis, Manli Zhu Nov 2005

Query Processing In Spatial Databases Containing Obstacles, Jun Zhang, Dimitris Papadias, Kyriakos Mouratidis, Manli Zhu

Research Collection School Of Computing and Information Systems

Despite the existence of obstacles in many database applications, traditional spatial query processing assumes that points in space are directly reachable and utilizes the Euclidean distance metric. In this paper, we study spatial queries in the presence of obstacles, where the obstructed distance between two points is defined as the length of the shortest path that connects them without crossing any obstacles. We propose efficient algorithms for the most important query types, namely, range search, nearest neighbours, e-distance joins, closest pairs and distance semi-joins, assuming that both data objects and obstacles are indexed by R-trees. The effectiveness of the proposed …

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On Security Notions Of Steganographic Systems, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim Nov 2005

On Security Notions Of Steganographic Systems, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim

Research Collection School Of Computing and Information Systems

We define the notion of pseudoprocessingness to formulate chosen-input-attack, chosen-stego-attack, and key-recovery. We then construct a efficient, provable secure steganographic algorithm against chosen-input-attack and key-recovery. So far as we know, this is the first paper dealing with those security notions.

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Anonymous Dos-Resistant Access Control Protocol Using Passwords For Wireless Networks, Zhiguo Wan, Robert H. Deng, Feng Bao, Akkihebbal L. Ananda Nov 2005

Anonymous Dos-Resistant Access Control Protocol Using Passwords For Wireless Networks, Zhiguo Wan, Robert H. Deng, Feng Bao, Akkihebbal L. Ananda

Research Collection School Of Computing and Information Systems

Wireless networks have gained overwhelming popularity over their wired counterpart due to their great flexibility and convenience, but access control of wireless networks has been a serious problem because of the open medium. Passwords remain the most popular way for access control as well as authentication and key exchange. But existing password-based access control protocols are not satisfactory in that they do not provide DoS-resistance or anonymity. In this paper we analyze the weaknesses of an access control protocol using passwords for wireless networks in IEEE LCN 2001, and propose a different access control protocol using passwords for wireless networks. …

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Informal Animation Sketching With K-Sketch, Richard Christopher Davis Oct 2005

Informal Animation Sketching With K-Sketch, Richard Christopher Davis

Research Collection School of Computing and Information Systems

Animation is a powerful medium that is accessible to few, because current animation tools are extremely complex. This complexity arises partially from current tools’ focus on precise, often unnecessary details and partially from the difficulty of finding a small but sufficiently powerful set of tool features. We are designing K-Sketch, an informal 2D animation tool that uses sketching and demonstration to radically reduce the time needed to create an animation. Our field studies investigating the needs of current anima-tion tool users and would-be users are helping us to mini-mize complexity by showing us how to prioritize the many possible tool …

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Agile Modeling, Agile Software Development, And Extreme Programming: The State Of Research, John Erickson, Kalle Lyytinen, Keng Siau Oct 2005

Agile Modeling, Agile Software Development, And Extreme Programming: The State Of Research, John Erickson, Kalle Lyytinen, Keng Siau

Research Collection School Of Computing and Information Systems

While there are many claims for the successful use of extreme programming (XP) and agile modeling (AM), and the proponents can often be vocal in the extreme regarding their supposed benefits, research evidence supporting proponents' claims is somewhat lacking. Currently, the only research appearing to investigate the phenomena consists of two prominent streams. A small number of case studies and experience reports that generally promote the success of XP in various development environments, and a well-established stream of research into pair programming has generated results that in part support the idea of XP. Research into AM appears to be even …

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Managerial Assessments Of E-Business Investment Opportunities: A Field Study, Anandhi S. Bharadwaj, Amrit Tiwana Oct 2005

Managerial Assessments Of E-Business Investment Opportunities: A Field Study, Anandhi S. Bharadwaj, Amrit Tiwana

Research Collection School Of Computing and Information Systems

Managers charged with assessing investment opportunities for information technologies such as e-business projects face considerable uncertainty in their decision-making processes. Contemporary theories of the firm and the normative prescriptions thereof emphasize the potential for such investments to augment firm-level knowledge and relational capabilities. However, prior research has not examined the relative emphases that managers place on the knowledge and relational capability-augmenting characteristics of the e-business investments. In this paper, we develop a model to assess whether managerial evaluations of e-business investment opportunities are consistent with these normative and theoretical prescriptions. A test of the model using survey data on 485 …

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Towards Semantic Service Request Of Web Service Composition, Qianhui Althea Liang, Jen-Yao Chung, Steven M. Miller Oct 2005

Towards Semantic Service Request Of Web Service Composition, Qianhui Althea Liang, Jen-Yao Chung, Steven M. Miller

Research Collection School Of Computing and Information Systems

When meeting the challenges in automatic and semi-automatic Web service composition, capturing the user's service demand and preferences is as important as knowing what the services can do. This paper discusses the idea of semantic service requests for composite services, and presents a way to model the elements of a composite service request as user preferences and constraints. The model is based on an interactive and iterative strategy meant to obtain the exact requirements from potential service consumers. The markup vocabularies and associated inference mechanism of OWL-S are used as a means to bring semantics to service requests. Language constructs …

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Nil Is Not Nothing: Recognition Of Chinese Network Informal Language Expressions, Yunqing Xia, Kam-Fai Wong, Wei Gao Oct 2005

Nil Is Not Nothing: Recognition Of Chinese Network Informal Language Expressions, Yunqing Xia, Kam-Fai Wong, Wei Gao

Research Collection School Of Computing and Information Systems

Informal language is actively used in network-mediated communication, e.g. chat room, BBS, email and text message. We refer the anomalous terms used in such context as network informal language (NIL) expressions. For example, “஧(ou3)” is used to replace “ᚒ(wo3)” in Chinese ICQ. Without unconventional resource, knowledge and techniques, the existing natural language processing approaches exhibit less effectiveness in dealing with NIL text. We propose to study NIL expressions with a NIL corpus and investigate techniques in processing NIL expressions. Two methods for Chinese NIL expression recognition are designed in NILER system. The experimental results show that pattern matching method produces …

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Nil Is Not Nothing: Recognition Of Chinese Network Informal Language Expressions, Yunqing Xia, Wong, Wei Gao, Wei Gao Oct 2005

Nil Is Not Nothing: Recognition Of Chinese Network Informal Language Expressions, Yunqing Xia, Wong, Wei Gao, Wei Gao

Research Collection School Of Computing and Information Systems

Informal language is actively used in network-mediated communication, e.g. chat room, BBS, email and text message. We refer the anomalous terms used in such context as network informal language (NIL) expressions. For example, “偶(ou3)” is used to replace “我(wo3)” in Chinese ICQ. Without unconventional resource, knowledge and techniques, the existing natural language processing approaches exhibit less effectiveness in dealing with NIL text. We propose to study NIL expressions with a NIL corpus and investigate techniques in processing NIL expressions. Two methods for Chinese NIL expression recognition are designed in NILER system. The experimental results show that pattern matching method produces …

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Common Pattern Discovery Using Earth Mover's Distance And Local Flow Maximization, Hung-Khoon Tan, Chong-Wah Ngo Oct 2005

Common Pattern Discovery Using Earth Mover's Distance And Local Flow Maximization, Hung-Khoon Tan, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we present a novel segmentation-insensitive approach for mining common patterns from 2 images. We develop an algorithm using the earth movers distance (EMD) framework, unary and adaptive neighborhood color similarity. We then propose a novel local flow maximization approach to provide the best estimation of location and scale of the common pattern. This is achieved by performing an iterative optimization in search of the most stable flows' centroid. Common pattern discovery is difficult owing to the huge search space and problem domain. We intend to solve this problem by reducing the search space through identifying the location …

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Informal Animation Sketching With K-Sketch, Richard C. Davis Oct 2005

Informal Animation Sketching With K-Sketch, Richard C. Davis

Research Collection School Of Computing and Information Systems

Animation is a powerful medium that is accessible to few, because current animation tools are extremely complex. This complexity arises partially from current tools’ focus on precise, often unnecessary details and partially from the difficulty of finding a small but sufficiently powerful set of tool features. We are designing K-Sketch, an informal 2D animation tool that uses sketching and demonstration to radically reduce the time needed to create an animation. Our field studies investigating the needs of current anima-tion tool users and would-be users are helping us to mini-mize complexity by showing us how to prioritize the many possible tool …

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And/Or Graph And Search Algorithm For Discovering Composite Web Services, Qianhui (Althea) Liang, Stanley Y. W. Su Oct 2005

And/Or Graph And Search Algorithm For Discovering Composite Web Services, Qianhui (Althea) Liang, Stanley Y. W. Su

Research Collection School Of Computing and Information Systems

This paper presents a formalization of the Web Service composition problem as a search problem in an AND/OR graph, and a search algorithm for searching the graph to identify composite service(s) that satisfies a Web Service request. Given a service request that can only be satisfied by a composition of Web Services, we identify the service categories that are relevant to the request and dynamically construct an AND/OR graph to capture the input/output dependencies among the Web Services of these service categories. The graph is modified, based on the information provided in the service request. The search algorithm is then …

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Dsim: A Distance-Based Indexing Method For Genomic Sequences, Xia Cao, Beng-Chin Ooi, Hwee Hwa Pang, Kian-Lee Tan, Anthony K. H. Tung Oct 2005

Dsim: A Distance-Based Indexing Method For Genomic Sequences, Xia Cao, Beng-Chin Ooi, Hwee Hwa Pang, Kian-Lee Tan, Anthony K. H. Tung

Research Collection School Of Computing and Information Systems

In this paper, we propose a Distance-based Sequence Indexing Method (DSIM) for indexing and searching genome databases. Borrowing the idea of video compression, we compress the genomic sequence database around a set of automatically selected reference words, formed from high-frequency data substrings and substrings in past queries. The compression captures the distance of each non-reference word in the database to some reference word. At runtime, a query is processed by comparing its substrings with the compressed data strings, through their distances to the reference words. We also propose an efficient scheme to incrementally update the reference words and the compressed …

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Automatic 3d Face Modeling Using 2d Active Appearance Models, Jianke Zhu, Steven Hoi, Michael R. Lyu Oct 2005

Automatic 3d Face Modeling Using 2d Active Appearance Models, Jianke Zhu, Steven Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Although a lot of promising research findings have been studied on 3D face modeling in the past years, it is still a challenge to generate realistic 3D human face models and facial animations. This paper presents a novel approach to model 3D faces automatically from still images or video sequences without manual interactions. Our proposed scheme comprises three steps. First, we offline construct 3D shape models using Active Appearance Models (AAMs), which saves large computation costs for online modeling. Second, based on the computed 3D shape models, we propose an efficient algorithm to estimate the parameters of 3D pose and …

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Managing Geography Learning Objects Using Personalized Project Spaces In G-Portal, Dion Hoe-Lian Goh, Aixin Sun, Wenbo Zong, Dan Wu, Ee Peng Lim, Yin-Leng Theng, John Hedberg, Chew-Hung Chang Sep 2005

Managing Geography Learning Objects Using Personalized Project Spaces In G-Portal, Dion Hoe-Lian Goh, Aixin Sun, Wenbo Zong, Dan Wu, Ee Peng Lim, Yin-Leng Theng, John Hedberg, Chew-Hung Chang

Research Collection School Of Computing and Information Systems

The personalized project space is an important feature in G-Portal that supports individual and group learning activities. Within such a space, its owner can create, delete, and organize metadata referencing learning objects on the Web. Browsing and querying are among the functions provided to access the metadata. In addition, new schemas can be added to accommodate metadata of diverse attribute sets. Users can also easily share metadata across different projects using a “copy-and-paste” approach. Finally, a viewer to support offline viewing of personalized project content is also provided.

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Forms Of Expression For Designing Visual Languages For Animation, Richard Christopher Davis, James A. Landay Sep 2005

Forms Of Expression For Designing Visual Languages For Animation, Richard Christopher Davis, James A. Landay

Research Collection School of Computing and Information Systems

We present further steps in our research into visual languages for animation. Animation is a rich mode of communication that is currently accessible to few, because animation systems are complex. Some systems try to make animation simple but put severe limits on users’ creative expression. Our field studies are demonstrating that would-be animators need to express animation in a wide variety of ways. We are developing a taxonomy of forms of expression for animation that will help the designers of visual languages for animation to determine which expressive forms to support. Our end goal is to build animation sketching systems …

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Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu Sep 2005

Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu

Research Collection School Of Computing and Information Systems

The Open Constraint Optimization Problem (OCOP) refers to the COP where constraints and variable domains can change over time and agents' opinions have to be sought over a distributed network to form a solution. The openness of the problem has caused conventional approaches to COP such as branch-and-bound to fail to find optimal solutions. OCOP is a new problem and the approach to find an optimal solution (minimum total cost) introduced in [1] is based on an unrealistic assumption that agents are willing to report their options in nondecreasing order of cost. In this paper, we study a generalized OCOP …

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New Efficient Mds Array Codes For Raid Part I: Reed-Solomon-Like Codes For Tolerating Three Disk Failures, Gui-Liang Feng, Robert H. Deng, Feng Bao, Jia-Chen Shen Sep 2005

New Efficient Mds Array Codes For Raid Part I: Reed-Solomon-Like Codes For Tolerating Three Disk Failures, Gui-Liang Feng, Robert H. Deng, Feng Bao, Jia-Chen Shen

Research Collection School Of Computing and Information Systems

This paper presents a class of binary maximum distance separable (MDS) array codes for tolerating disk failures in redundant arrays of inexpensive disks (RAID) architecture based on circular permutation matrices. The size of the information part is m×n, the size of the parity-check part is m×3, and the minimum distance is 4, where n is the number of information disks, the number of parity-check disks is 3, and (m+1) is a prime integer. In practical applications, m can be very large and n is from 20 to 50. The code rate is R=n/(n+3). These codes can be used for tolerating …

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On Organizing And Accessing Geospatial And Georeferenced Web Resources Using The G-Portal System, Zehua Liu, Ee Peng Lim, Yin-Leng Theng, Dion Hoe-Lian Goh, Wee-Keong Ng Sep 2005

On Organizing And Accessing Geospatial And Georeferenced Web Resources Using The G-Portal System, Zehua Liu, Ee Peng Lim, Yin-Leng Theng, Dion Hoe-Lian Goh, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

In order to organise and manage geospatial and georeferenced information on the Web making them convenient for searching and browsing, a digital portal known as G-Portal has been designed and implemented. Compared to other digital libraries, G-Portal is unique for several of its features. It maintains metadata resources in XML with flexible resource schemas. Logical groupings of metadata resources as projects and layers are possible to allow the entire metadata collection to be partitioned differently for users with different information needs. These metadata resources can be displayed in both the classification-based and map-based interfaces provided by G-Portal. G-Portal further incorporates …

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Cuhk At Imageclef 2005: Cross-Language And Cross-Media Image Retrieval, Steven C. H. Hoi, J. Zhu, M. Lyu Sep 2005

Cuhk At Imageclef 2005: Cross-Language And Cross-Media Image Retrieval, Steven C. H. Hoi, J. Zhu, M. Lyu

Research Collection School Of Computing and Information Systems

In this paper, we describe our studies of cross-language and cross-media image retrieval at the ImageCLEF 2005. This is the first participation of our CUHK (The Chinese University of Hong Kong) group at ImageCLEF. The task in which we participated is the “bilingual ad hoc retrieval” task. There are three major focuses and contributions in our participation. The first is the empirical evaluation of language models and smoothing strategies for cross-language image retrieval. The second is the evaluation of cross-media image retrieval, i.e., combining text and visual contents for image retrieval. The last is the evaluation of bilingual image retrieval …

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Strategic Implications Of Mobile Technology: A Case Study Using Value-Focused Thinking, H. Sheng, Fiona Fui-Hoon Nah, Keng Siau Sep 2005

Strategic Implications Of Mobile Technology: A Case Study Using Value-Focused Thinking, H. Sheng, Fiona Fui-Hoon Nah, Keng Siau

Research Collection School Of Computing and Information Systems

Mobile technology extends computing and the Internet into the wireless medium, and provides greater flexibility in communication, collaboration, and information sharing. In this research, we used the ‘Value-Focused Thinking’ approach to examine the strategic implications of mobile technology in a leading publishing company. The result is a means-ends objective network that depicts the fundamental objectives of using mobile technology and how the fundamental objectives can be achieved through means objectives. The research findings suggest three main strategic implications of mobile technology: (1) improve working process; (2) increase internal communication and knowledge sharing; and (3) enhance sales and marketing effectiveness.

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Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay Sep 2005

Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay

Research Collection School Of Computing and Information Systems

We present further steps in our research into visual languages for animation. Animation is a rich mode of communication that is currently accessible to few, because animation systems are complex. Some systems try to make animation simple but put severe limits on users’ creative expression. Our field studies are demonstrating that would-be animators need to express animation in a wide variety of ways. We are developing a taxonomy of forms of expression for animation that will help the designers of visual languages for animation to determine which expressive forms to support. Our end goal is to build animation sketching systems …

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Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo Sep 2005

Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo

Research Collection School Of Computing and Information Systems

In a rapidly changing environment, the behavior and decision-making power of agents may have to be adaptive with respect to a fluctuating autonomy. In this paper, a centralized fuzzy approach is proposed to sense changes in environmental conditions and translate them to changes in agent autonomy. A distributed coalition formation scheme is then applied to allow agents in the new autonomy to renegotiate to establish schedule consistency. The proposed framework is applied to a real-time logistics control of a military hazardous material storage facility under peace-to-war transition.

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Security Analysis And Improvement Of Return Routability Protocol, Ying Qiu, Jianying Zhou, Robert H. Deng Sep 2005

Security Analysis And Improvement Of Return Routability Protocol, Ying Qiu, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

Mobile communication plays a more and more important role in computer networks. How to authenticate a new connecting address belonging to a said mobile node is one of the key issues in mobile networks. This paper analyzes the Return Routability (RR) protocol and proposes an improved security solution for the RR protocol without changing its architecture. With the improvement, three types of redirect attacks can be prevented.

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Low Latency Multimedia Broadcast In Multi-Rate Wireless Meshes, Chun-Tong Chou, Archan Misra Sep 2005

Low Latency Multimedia Broadcast In Multi-Rate Wireless Meshes, Chun-Tong Chou, Archan Misra

Research Collection School Of Computing and Information Systems

In a multi-rate wireless network, a node can dynamically adjust its link transmission rate by switching between different modulation schemes. For the current IEEE802.11a/b/g standards, this rate adjustment is limited to unicast traffic only while multicast and broadcast traffic is always transmitted at the lowest possible rate. In this paper, we consider a novel type of multi-rate mesh networks where a node can dynamically adjust its link layer multicast rates to its neighbours. In particular, we consider the problem of realising low latency network-wide broadcast in this type of multi-rate wireless meshes. We will first show that the multi-rate broadcast …

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Information Search Patterns In E-Commerce Product Comparison Services, Fiona Fui-Hoon Nah, Hong-Hee Lee, Liqiang Chen Aug 2005

Information Search Patterns In E-Commerce Product Comparison Services, Fiona Fui-Hoon Nah, Hong-Hee Lee, Liqiang Chen

Research Collection School Of Computing and Information Systems

The presentation of product information is very important in e-commerce websites. In this research, we study how disposition styles can influence users‟ search patterns in product comparison services of e-commerce websites. Our results show that people are inclined to use feature information paths in vertical disposition style and product information paths in horizontal disposition style. The results also indicate that there are more feature paths than product paths in the earlier stage of product comparison, and more product paths than feature paths in the latter stage of product comparison. Based on Gensch‟s two-stage choice model and the results of our …

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Evaluation Of Time-Varying Availability In Multi-Echelon Inventory System With Combat Damage, Hoong Chuin Lau, Huawei Song Aug 2005

Evaluation Of Time-Varying Availability In Multi-Echelon Inventory System With Combat Damage, Hoong Chuin Lau, Huawei Song

Research Collection School Of Computing and Information Systems

The models for multi-echelon inventory systems in existing literatures predominantly address failures due to reliability in peacetime. In wartime or even peacetime operational scenarios, unexpected combat damage can cause a large number of systems to be heavily damaged, to the extent that they become irreparable. In this paper, we study a multi-echelon spare parts support system under combat damage, discuss the replenishment policy and propose an approximate method to evaluate the time-varying system performance operational availability considering the effect of passivation. Experiments show our model works well and efficiently against simulation.

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End-Users’ Acceptance Of Enterprise Resource Planning Systems: An Investigation Using Grounded Theory Approach, Fiona Fui-Hoon Nah, Xin Tan, Monica Beethe Aug 2005

End-Users’ Acceptance Of Enterprise Resource Planning Systems: An Investigation Using Grounded Theory Approach, Fiona Fui-Hoon Nah, Xin Tan, Monica Beethe

Research Collection School Of Computing and Information Systems

The success of ERP implementation depends, to a large extent, on the intensity and nature of its use by end-users. Therefore, it is important to understand the phenomena underlying end-users’ acceptance of ERP systems. This study was conducted at a large institution that implemented an ERP system. It uses the grounded theory approach to inductively develop a model that highlights key factors influencing end-users’ acceptance of ERP systems.

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