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Articles 31 - 60 of 109
Full-Text Articles in Physical Sciences and Mathematics
And/Or Graph And Search Algorithm For Discovering Composite Web Services, Qianhui (Althea) Liang, Stanley Y. W. Su
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 …
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
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 …
Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo
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.
Security Analysis And Improvement Of Return Routability Protocol, Ying Qiu, Jianying Zhou, Robert H. Deng
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.
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
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.
Cuhk At Imageclef 2005: Cross-Language And Cross-Media Image Retrieval, Steven C. H. Hoi, J. Zhu, M. Lyu
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 …
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
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 …
Low Latency Multimedia Broadcast In Multi-Rate Wireless Meshes, Chun-Tong Chou, Archan Misra
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 …
Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay
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 …
Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu
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 …
Evaluation Of Time-Varying Availability In Multi-Echelon Inventory System With Combat Damage, Hoong Chuin Lau, Huawei Song
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.
Wmxml: A System For Watermarking Xml Data, Xuan Zhou, Hwee Hwa Pang, Kian-Lee Tan, Dhruv Mangla
Wmxml: A System For Watermarking Xml Data, Xuan Zhou, Hwee Hwa Pang, Kian-Lee Tan, Dhruv Mangla
Research Collection School Of Computing and Information Systems
As increasing amount of data is published in the form of XML, copyright protection of XML data is becoming an important requirement for many applications. While digital watermarking is a widely used measure to protect digital data from copyright offences, the complex and flexible construction of XML data poses a number of challenges to digital watermarking, such as re-organization and alteration attacks. To overcome these challenges, the watermarking scheme has to be based on the usability of data and the underlying semantics like key attributes and functional dependencies. In this paper, we describe WmXML, a system for watermarking XML documents. …
Medoid Queries In Large Spatial Databases, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou
Medoid Queries In Large Spatial Databases, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou
Research Collection School Of Computing and Information Systems
Assume that a franchise plans to open k branches in a city, so that the average distance from each residential block to the closest branch is minimized. This is an instance of the k-medoids problem, where residential blocks constitute the input dataset and the k branch locations correspond to the medoids. Since the problem is NP-hard, research has focused on approximate solutions. Despite an avalanche of methods for small and moderate size datasets, currently there exists no technique applicable to very large databases. In this paper, we provide efficient algorithms that utilize an existing data-partition index to achieve low CPU …
Translation Initiation Sites Prediction With Mixture Gaussian Models In Human Cdna Sequences, G. Li, Tze-Yun Leong, Louxin Zhang
Translation Initiation Sites Prediction With Mixture Gaussian Models In Human Cdna Sequences, G. Li, Tze-Yun Leong, Louxin Zhang
Research Collection School Of Computing and Information Systems
Translation initiation sites (TISs) are important signals in cDNA sequences. Many research efforts have tried to predict TISs in cDNA sequences. In this paper, we propose to use mixture Gaussian models for TIS prediction. Using both local features and some features generated from global measures, the proposed method predicts TISs with a sensitivity of 98 percent and a specificity of 93.6 percent. Our method outperforms many other existing methods in sensitivity while keeping specificity high. We attribute the improvement in sensitivity to the nature of the global features and the mixture Gaussian models. © 2005 IEEE.
Constrained Shortest Path Computation, Manolis Terrovitis, Spiridon Bakiras, Dimitris Papadias, Kyriakos Mouratidis
Constrained Shortest Path Computation, Manolis Terrovitis, Spiridon Bakiras, Dimitris Papadias, Kyriakos Mouratidis
Research Collection School Of Computing and Information Systems
This paper proposes and solves a-autonomy and k-stops shortest path problems in large spatial databases. Given a source s and a destination d, an aautonomy query retrieves a sequence of data points connecting s and d, such that the distance between any two consecutive points in the path is not greater than a. A k-stops query retrieves a sequence that contains exactly k intermediate data points. In both cases our aim is to compute the shortest path subject to these constraints. Assuming that the dataset is indexed by a data-partitioning method, the proposed techniques initially compute a sub-optimal path by …
Geogdl: A Web-Based Approach To Geography Examination, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng
Geogdl: A Web-Based Approach To Geography Examination, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng
Research Collection School Of Computing and Information Systems
The traditional educational approach with students as passive recipients has been the subject of criticism. A constructivist learner-centered approach towards education has been argued to produce greater internalization and application of knowledge compared to the traditional teacher-centered, transmission-oriented approach. Nevertheless, contemporary instructional design models argue for the use and integration of both approaches especially in complex learning tasks. This paper describes GeogDL, a Web-based application developed above a digital library of geographical resources for Singapore students preparing to take a national examination in geography. GeogDL is unique in that it not only provides an environment for active learning, it also …
Web Mining - The Ontology Approach, Ee Peng Lim, Aixin Sun
Web Mining - The Ontology Approach, Ee Peng Lim, Aixin Sun
Research Collection School Of Computing and Information Systems
The World Wide Web today provides users access to extremely large number of Web sites many of which contain information of education and commercial values. Due to the unstructured and semi-structured nature of Web pages and the design idiosyncrasy of Web sites, it is a challenging task to develop digital libraries for organizing and managing digital content from the Web. Web mining research, in its last 10 years, has on the other hand made significant progress in categorizing and extracting content from the Web. In this paper, we represent ontology as a set of concepts and their inter-relationships relevant to …
Dispatching Vehicles In A Mega Container Terminal, Ebru K. Bish, Frank Y. Chen, Thin Yin Leong, Barry L. Nelson, Jonathan W. C. Ng, David Simchi-Levi
Dispatching Vehicles In A Mega Container Terminal, Ebru K. Bish, Frank Y. Chen, Thin Yin Leong, Barry L. Nelson, Jonathan W. C. Ng, David Simchi-Levi
Research Collection School Of Computing and Information Systems
We consider a container terminal discharging and uploading containers to and from ships. The discharged containers are stored at prespecified storage locations in the terminal yard. Containers are moved between the ship area and the yard using a fleet of vehicles, each of which can carry one container at a time. The problem is to dispatch vehicles to the containers so as to minimize the total time it takes to serve a ship, which is the total time it takes to discharge all containers from the ship and upload new containers onto the ship. We develop easily implementable heuristic algorithms …
Tuning Tabu Search Strategies Via Visual Diagnosis, Steven Halim, Wee Chong Wan, Hoong Chuin Lau
Tuning Tabu Search Strategies Via Visual Diagnosis, Steven Halim, Wee Chong Wan, Hoong Chuin Lau
Research Collection School Of Computing and Information Systems
While designing working metaheuristics can be straightforward, tuning them to solve the underlying combinatorial optimization problem well can be tricky. Several tuning methods have been proposed but they do not address the new aspect of our proposed classification of the metaheuristic tuning problem: tuning search strategies. We propose a tuning methodology based on Visual Diagnosis and a generic tool called Visualizer for Metaheuristics Development Framework(V-MDF) to address specifically the problem of tuning search (particularly Tabu Search) strategies. Under V-MDF, we propose the use of a Distance Radar visualizer where the human and computer can collaborate to diagnose the occurrence of …
Descriptive Naming Of Context Data Providers, Norman H. Cohen, Paul Castro, Archan Misra
Descriptive Naming Of Context Data Providers, Norman H. Cohen, Paul Castro, Archan Misra
Research Collection School Of Computing and Information Systems
Much context data comes from mobile, transient, and unreliable sources. Such resources are best specified by descriptive names identifying what data is needed rather than which source is to provide it. The design of descriptive names has important consequences, but until now little attention has been focused on this problem. We propose a descriptive naming system for providers of context data that provides more flexibility and power than previous naming systems by classifying data providers into “provider kinds” that are organized in an evolving hierarchy of subkinds and superkinds. New provider kinds can be inserted in the hierarchy not only …
Middleware Architecture For Evaluation And Selection Of 3rd Party Web Services For Service Providers, Dipanjan Chakraborty, Suraj K. Jaiswal, Archan Misra, Amit A. Nanavati
Middleware Architecture For Evaluation And Selection Of 3rd Party Web Services For Service Providers, Dipanjan Chakraborty, Suraj K. Jaiswal, Archan Misra, Amit A. Nanavati
Research Collection School Of Computing and Information Systems
This paper presents an architecture to facilitate efficient evaluation and selection of 3rd party Web services for service providers. Most service provider architectures have primarily focused on providing Web service front ends to legacy systems, aggregating and delivering services via workflows. These architectures primarily considered static business contracts between the service provider and its (Web-service enabled) business partners. This approach makes these architectures inflexible to variations in business requirement, partners' performance and customer requirements. Our architecture provides a flexible means for service providers to optimize business performance. Based on the historical performance, extant context, and optimising business rules, the appropriate …
Exploiting Belief Bounds: Practical Pomdps For Personal Assistant Agents, Pradeep Varakantham, Rajiv Maheswaran, Milind Tambe
Exploiting Belief Bounds: Practical Pomdps For Personal Assistant Agents, Pradeep Varakantham, Rajiv Maheswaran, Milind Tambe
Research Collection School Of Computing and Information Systems
Agents or agent teams deployed to assist humans often face the challenges of monitoring the state of key processes in their environment (including the state of their human users themselves) and making periodic decisions based on such monitoring. POMDPs appear well suited to enable agents to address these challenges, given the uncertain environment and cost of actions, but optimal policy generation for POMDPs is computationally expensive. This paper introduces three key techniques to speedup POMDP policy generation that exploit the notion of progress or dynamics in personal assistant domains. Policy computation is restricted to the belief space polytope that remains …
Social Network Discovery By Mining Spatio-Temporal Events, Hady Lauw, Ee Peng Lim, Hwee Hwa Pang, Teck-Tim Tan
Social Network Discovery By Mining Spatio-Temporal Events, Hady Lauw, Ee Peng Lim, Hwee Hwa Pang, Teck-Tim Tan
Research Collection School Of Computing and Information Systems
Knowing patterns of relationship in a social network is very useful for law enforcement agencies to investigate collaborations among criminals, for businesses to exploit relationships to sell products, or for individuals who wish to network with others. After all, it is not just what you know, but also whom you know, that matters. However, finding out who is related to whom on a large scale is a complex problem. Asking every single individual would be impractical, given the huge number of individuals and the changing dynamics of relationships. Recent advancement in technology has allowed more data about activities of individuals …
Multibiometrics Based On Palmprint And Handgeometry, Xiao-Yong Wei, Dan Xu, Chong-Wah Ngo
Multibiometrics Based On Palmprint And Handgeometry, Xiao-Yong Wei, Dan Xu, Chong-Wah Ngo
Research Collection School Of Computing and Information Systems
This paper described our approach of multibiometrics in a single image. Firstly, a new method for capturing the key points of hand geometry is proposed. Then, we described our new method of palmprint feature extracting. By using projection transform and wavelet transform, this method considered both the global feature and local detail of a palmprint texture and proposed a new kind of palmprint feature. We also proposed a twice segmentation method for handgeometry feature extraction. In the processing of feature matching, we analyzed the weakness of the traditional Euclidian Square Norm method, and introduced an improved method. The experimental results …
Co-Clustering Of Time-Evolving News Story With Transcript And Keyframe, Xiao Wu, Chong-Wah Ngo, Qing Li
Co-Clustering Of Time-Evolving News Story With Transcript And Keyframe, Xiao Wu, Chong-Wah Ngo, Qing Li
Research Collection School Of Computing and Information Systems
This paper presents techniques in clustering the same-topic news stories according to event themes. We model the relationship of stories with textual and visual concepts under the representation of bipartite graph. The textual and visual concepts are extracted respectively from speech transcripts and keyframes. Co-clustering algorithm is employed to exploit the duality of stories and textual-visual concepts based on spectral graph partitioning. Experimental results on TRECVID-2004 corpus show that the co-clustering of news stories with textual-visual concepts is significantly better than the co-clustering with either textual or visual concept alone.
Hot Event Detection And Summarization By Graph Modeling And Matching, Yuxin Peng, Chong-Wah Ngo
Hot Event Detection And Summarization By Graph Modeling And Matching, Yuxin Peng, Chong-Wah Ngo
Research Collection School Of Computing and Information Systems
This paper proposes a new approach for hot event detection and summarization of news videos. The approach is mainly based on two graph algorithms: optimal matching (OM) and normalized cut (NC). Initially, OM is employed to measure the visual similarity between all pairs of events under the one-to-one mapping constraint among video shots. Then, news events are represented as a complete weighted graph and NC is carried out to globally and optimally partition the graph into event clusters. Finally, based on the cluster size and globality of events, hot events can be automatically detected and selected as the summaries of …
Synthesis Of Distributed Processes From Scenario-Based Specifications, Jun Sun, Jin Song Dong
Synthesis Of Distributed Processes From Scenario-Based Specifications, Jun Sun, Jin Song Dong
Research Collection School Of Computing and Information Systems
Given a set of sequence diagrams, the problem of synthesis is of deciding whether there exists a satisfying object system and if so, synthesize one automatically. It is crucial in the development of complex systems, since sequence diagrams serve as the manifestation of use cases and if synthesizable they could lead directly to implementation. It is even more interesting (and harder) if the synthesized object system is distributed. In this paper, we propose a systematic way of synthesizing distributed processes from Live Sequence Charts. The basic idea is to first construct a CSP specification from the LSC specification, and then …
Deposit-Case Attack Against Secure Roaming, Guomin Yang, Duncan S. Wong, Xiaotie Deng
Deposit-Case Attack Against Secure Roaming, Guomin Yang, Duncan S. Wong, Xiaotie Deng
Research Collection School Of Computing and Information Systems
A secure roaming protocol involves three parties: a roaming user, a visiting foreign server and the user’s home server. The protocol allows the user and the foreign server to establish a session key and carry out mutual authentication with the help of the home server. In the mutual authentication, user authentication is generally done in two steps. First, the user claims that a particular server is his home server. Second, that particular server is called in by the foreign server for providing a ‘credential’ which testifies the user’s claim. We present a new attacking technique which allows a malicious server …
Emd-Based Video Clip Retrieval By Many-To-Many Matching, Yuxin Peng, Chong-Wah Ngo
Emd-Based Video Clip Retrieval By Many-To-Many Matching, Yuxin Peng, Chong-Wah Ngo
Research Collection School Of Computing and Information Systems
This paper presents a new approach for video clip retrieval based on Earth Mover's Distance (EMD). Instead of imposing one-to-one matching constraint as in [11, 14], our approach allows many-to-many matching methodology and is capable of tolerating errors due to video partitioning and various video editing effects. We formulate clip-based retrieval as a graph matching problem in two stages. In the first stage, to allow the matching between a query and a long video, an online clip segmentation algorithm is employed to rapidly locate candidate clips for similarity measure. In the second stage, a weighted graph is constructed to model …
Approximate Strategic Reasoning Through Hierarchical Reduction Of Large Symmetric Games, Michael P. Wellman, Daniel M. Reeves, Kevin M. Lochner, Shih-Fen Cheng, Rahul Suri
Approximate Strategic Reasoning Through Hierarchical Reduction Of Large Symmetric Games, Michael P. Wellman, Daniel M. Reeves, Kevin M. Lochner, Shih-Fen Cheng, Rahul Suri
Research Collection School Of Computing and Information Systems
To deal with exponential growth in the size of a game with the number of agents, we propose an approximation based on a hierarchy of reduced games. The reduced game achieves savings by restricting the number of agents playing any strategy to fixed multiples. We validate the idea through experiments on randomly generated local-effect games. An extended application to strategic reasoning about a complex trading scenario motivates the approach, and demonstrates methods for game-theoretic reasoning over incompletely-specified games at multiple levels of granularity.