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Articles 6391 - 6420 of 6884

Full-Text Articles in Physical Sciences and Mathematics

Structuring Home Video By Snippet Detection And Pattern Parsing, Zailiang Pan, Chong-Wah Ngo Oct 2004

Structuring Home Video By Snippet Detection And Pattern Parsing, Zailiang Pan, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Hand-held camcorders have been popularly used in capturing and documenting daily lives. Nonetheless, searching for personal memories in home videos is still a laborious task. This paper describes novel approaches in detecting snippets and patterns in home videos for content indexing. To deal with the fact that most shots are long and with handshake artifacts, a motion analysis algorithm based on Kalman filter and finite state machine is proposed to decompose videos into tables of snippets. Each snippet is represented by a set of moving and static patterns. The moving patterns are automatically detected and tracked, while the static patterns …

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Deformable Object Model Matching By Topological And Geometric Similarity, Kwok-Leung Tan, Rynson W. H. Lau, Chong-Wah Ngo Oct 2004

Deformable Object Model Matching By Topological And Geometric Similarity, Kwok-Leung Tan, Rynson W. H. Lau, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we present a novel method for efficient 3D model comparison. The method is designed to match highly deformed models through capturing two types of information. First, we propose a feature point extraction algorithm, which is based on “Level Set Diagram”, to reliably capture the topological points of a general 3D model. These topological points represent the skeletal structure of the model. Second, we also capture both spatial and curvature information, which describes the global surface of a 3D model. This is different from traditional topological 3D matching methods that use only low-dimension local features. Our method can …

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A Novel Log-Based Relevance Feedback Technique In Content-Based Image Retrieval, Steven C. H. Hoi, Michael R. Lyu Oct 2004

A Novel Log-Based Relevance Feedback Technique In Content-Based Image Retrieval, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Relevance feedback has been proposed as an important technique to boost the retrieval performance in content-based image retrieval (CBIR). However, since there exists a semantic gap between low-level features and high-level semantic concepts in CBIR, typical relevance feedback techniques need to perform a lot of rounds of feedback for achieving satisfactory results. These procedures are time-consuming and may make the users bored in the retrieval tasks. For a long-term study purpose in CBIR, we notice that the users' feedback logs can be available and employed for helping the retrieval tasks in CBIR systems. In this paper, we propose a novel …

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Comments On "A Practical (T, N) Threshold Proxy Signature Scheme Based On The Rsa Cryptosystem", Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng Oct 2004

Comments On "A Practical (T, N) Threshold Proxy Signature Scheme Based On The Rsa Cryptosystem", Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

In a (t, n) threshold proxy signature scheme based on RSA, any t or more proxy signers can cooperatively generate a proxy signature while t-1 or fewer of them can't do it. The threshold proxy signature scheme uses the RSA cryptosystem to generate the private and the public key of the signers. In this article, we discuss the implementation and comparison of some threshold proxy signature schemes that are based on the RSA cryptosystem. Comparison is done on the basis of time complexity, space complexity and communication overhead. We compare the performance of four schemes: Hwang et al., Wen et …

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Blocking Reduction Strategies In Hierarchical Text Classification, Ee Peng Lim, Aixin Sun, Wee-Keong Ng, Jaideep Srivastava Oct 2004

Blocking Reduction Strategies In Hierarchical Text Classification, Ee Peng Lim, Aixin Sun, Wee-Keong Ng, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

One common approach in hierarchical text classification involves associating classifiers with nodes in the category tree and classifying text documents in a top-down manner. Classification methods using this top-down approach can scale well and cope with changes to the category trees. However, all these methods suffer from blocking which refers to documents wrongly rejected by the classifiers at higher-levels and cannot be passed to the classifiers at lower-levels. We propose a classifier-centric performance measure known as blocking factor to determine the extent of the blocking. Three methods are proposed to address the blocking problem, namely, threshold reduction, restricted voting, and …

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Dynamic Access Control For Multi-Privileged Group Communications, Di Ma, Robert H. Deng, Yongdong Wu, Tieyan Li Oct 2004

Dynamic Access Control For Multi-Privileged Group Communications, Di Ma, Robert H. Deng, Yongdong Wu, Tieyan Li

Research Collection School Of Computing and Information Systems

Recently, there is an increase in the number of group communication applications which support multiple service groups of different access privileges. Traditional access control schemes for group applications assume that all the group members have the same access privilege and mostly focus on how to reduce rekeying messages upon user joining and leaving. Relatively little research effort has been spent to address security issues for group communications supporting multiple access privileges. In this paper, we propose a dynamic access control scheme for group communications which support multiple service groups with different access privileges. Our scheme allows dynamic formation of service …

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Airconn: A Framework For Tiered Services In Public Wireless Lan Hot Spots, A. Acharya, C. Bisdikian, Archan Misra, Y. Ko Oct 2004

Airconn: A Framework For Tiered Services In Public Wireless Lan Hot Spots, A. Acharya, C. Bisdikian, Archan Misra, Y. Ko

Research Collection School Of Computing and Information Systems

Access to the data services via wireless LANs at private and public hot spot sites is becoming commonplace. The goal of the airConn project is to define an architecture and a prototype implementation that enable the provision of premium and non-premium service tiers for both transient and nontransient users of wireless hot spots. airConn provides for dynamic renegotiation of service tiers and facilitates various billing modes. Thus, it enables service providers to increase their revenue opportunities via multiple flexibility manageable service offerings.

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Informal Animation Sketching: Requirements And Design, Richard C. Davis, James A. Landay Oct 2004

Informal Animation Sketching: Requirements And Design, Richard C. Davis, James A. Landay

Research Collection School Of Computing and Information Systems

We present an interface design for creating informal animations from sketches. Current tools for creating animation are extremely complex. This makes it difficult for designers to prototype animations and nearly impossible for novices to create them at all. Simple animation systems exist but severely restrict the types of motion that can be represented. To guide our design of an animation sketching interface, we conducted field studies into the needs of professional and novice animators. These studies show the wide variety of motions that users desire in informal animations and indicate how to prioritize these types of otion. The interface described …

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Design And Analysis Of A Cooperative Medium Access Scheme For Wireless Mesh Networks, Arup Acharya, Archan Misra, Sorav Bansal Oct 2004

Design And Analysis Of A Cooperative Medium Access Scheme For Wireless Mesh Networks, Arup Acharya, Archan Misra, Sorav Bansal

Research Collection School Of Computing and Information Systems

This paper presents the detailed design and performance analysis of MACA-P, a RTS/CTS based MAC protocol, that enables simultaneous transmissions in wireless mesh networks. The IEEE 802.11 DCF MAC prohibits any parallel transmission in the neighborhood of either a sender or a receiver (of an ongoing transmission). MACA-P is a set of enhancements to the 802.11 MAC that allows parallel transmissions in situations when two neighboring nodes are either both receivers or transmitters, but a receiver and a transmitter are not neighbors. The performance of MACA-P in terms of system throughput is obtained through a simulation of the protocol using …

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A Development Framework For Rapid Metaheuristics Hybridization, Hoong Chuin Lau, M. K. Lim, W. C. Wan, S. Halim Sep 2004

A Development Framework For Rapid Metaheuristics Hybridization, Hoong Chuin Lau, M. K. Lim, W. C. Wan, S. Halim

Research Collection School Of Computing and Information Systems

While meta-heuristics are effective for solving large-scale combinatorial optimization problems, they result from time-consuming trial-and-error algorithm design tailored to specific problems. For this reason, a software tool for rapid prototyping of algorithms would save considerable resources. This work presents a generic software framework that reduces development time through abstract classes and software reuse, and more importantly, aids design with support of user-defined strategies and hybridization of meta-heuristics. Most interestingly, we propose a novel way of redefining hybridization with the use of the "request and response" metaphor, which form an abstract concept for hybridization. Different hybridization schemes can now be formed …

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A Spectroscopy Of Texts For Effective Clustering, Wenyuan Li, Wee-Keong Ng, Kok-Leong Ong, Ee Peng Lim Sep 2004

A Spectroscopy Of Texts For Effective Clustering, Wenyuan Li, Wee-Keong Ng, Kok-Leong Ong, Ee Peng Lim

Research Collection School Of Computing and Information Systems

For many clustering algorithms, such as k-means, EM, and CLOPE, there is usually a requirement to set some parameters. Often, these parameters directly or indirectly control the number of clusters to return. In the presence of different data characteristics and analysis contexts, it is often difficult for the user to estimate the number of clusters in the data set. This is especially true in text collections such as Web documents, images or biological data. The fundamental question this paper addresses is: ldquoHow can we effectively estimate the natural number of clusters in a given text collection?rdquo. We propose to use …

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Sclope: An Algorithm For Clustering Data Streams Of Categorical Attributes, Kok-Leong Ong, Wenyuan Li, Wee-Keong Ng, Ee Peng Lim Sep 2004

Sclope: An Algorithm For Clustering Data Streams Of Categorical Attributes, Kok-Leong Ong, Wenyuan Li, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Clustering is a difficult problem especially when we consider the task in the context of a data stream of categorical attributes. In this paper, we propose SCLOPE, a novel algorithm based on CLOPE's intuitive observation about cluster histograms. Unlike CLOPE however, our algorithm is very fast and operates within the constraints of a data stream environment. In particular, we designed SCLOPE according to the recent CluStream framework. Our evaluation of SCLOPE shows very promising results. It consistently outperforms CLOPE in speed and scalability tests on our data sets while maintaining high cluster purity; it also supports cluster analysis that other …

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A Two-Level Framework For Coalition Formation Via Optimization And Agent Negotiation, Hoong Chuin Lau, Lei Zhang Sep 2004

A Two-Level Framework For Coalition Formation Via Optimization And Agent Negotiation, Hoong Chuin Lau, Lei Zhang

Research Collection School Of Computing and Information Systems

We present a two-level coalition formation approach based on a centralized optimization model on the upper level, and a distributed agent-negotiation model on the lower level. This approach allows us to balance agent self-interests against a high joint utility. Experimental results show that the two-level coalition formation mechanism will increase not only the overall utility of the coalition, but also the individual utility of most participating agents. The results also suggest it is better for the agents to be partially cooperative rather than either fully cooperative or self-interested in our setting.

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Shared-Storage Auction Ensures Data Availability, Hady W. Lauw, Siu-Cheung Hui, Edmund M. K. Lai Sep 2004

Shared-Storage Auction Ensures Data Availability, Hady W. Lauw, Siu-Cheung Hui, Edmund M. K. Lai

Research Collection School Of Computing and Information Systems

Most current e-auction systems are based on the client-server architecture. Such centralized systems provide a single point of failure and control. In contrast, peer-to-peer systems permit distributed control and minimize individual node and link failures' impact on the system. The shared-storage-based auction model described decentralizes services among peers to share the required processing load and aggregates peers' resources for common use. The model is based on the principles of local computation at each peer, direct inter-peer communication, and a shared storage space.

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Robust Classification Of Event-Related Potential For Brain-Computer Interface, Manoj Thulasidas Sep 2004

Robust Classification Of Event-Related Potential For Brain-Computer Interface, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

We report the implementation of a text input application (speller) based on the P300 event related potential. We obtain high accuracies by using an SVM classifier and a novel feature. These techniques enable us to maintain fast performance without sacrificing the accuracy, thus making the speller usable in an online mode. In order to further improve the usability, we perform various studies on the data with a view to minimizing the training time required. We present data collected from nine healthy subjects, along with the high accuracies (of the order of 95% or more) measured online. We show that the …

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Towards Personalised Web Intelligence, Ah-Hwee Tan, Hwee-Leng Ong, Hong Pan, Jamie Ng, Qiu-Xiang Li Sep 2004

Towards Personalised Web Intelligence, Ah-Hwee Tan, Hwee-Leng Ong, Hong Pan, Jamie Ng, Qiu-Xiang Li

Research Collection School Of Computing and Information Systems

The Flexible Organizer for Competitive Intelligence (FOCI) is a personalised web intelligence system that provides an integrated platform for gathering, organising, tracking, and disseminating competitive information on the web. FOCI builds personalised information portfolios through a novel method called User-Configurable Clustering, which allows a user to personalise his/her portfolios in terms of the content as well as the organisational structure. This paper outlines the key challenges we face in personalised information management and gives a detailed account of FOCI’s underlying personalisation mechanism. For a quantitative evaluation of the system’s performance, we propose a set of performance indices based on information …

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Security Analysis Of Two Signcryption Schemes, Guilin Wang, Robert H. Deng, Dongjin Kwak, Sangjae Moon Sep 2004

Security Analysis Of Two Signcryption Schemes, Guilin Wang, Robert H. Deng, Dongjin Kwak, Sangjae Moon

Research Collection School Of Computing and Information Systems

Signcryption is a new cryptographic primitive that performs signing and encryption simultaneously, at a cost significantly lower than that required by the traditional signature-then-encryption approach. In this paper, we present a security analysis of two such schemes: the Huang-Chang convertible signcryption scheme, and the Kwak-Moon group signcryption scheme. Our results show that both schemes are insecure. Specifically, the Huang-Chang scheme fails to provide confidentiality, while the Kwak-Moon scheme does not satisfy the properties of unforgeability, coalition-resistance, and traceability.

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A Visual Language For Animating Sketches, Richard C. Davis, James A. Landay Sep 2004

A Visual Language For Animating Sketches, Richard C. Davis, James A. Landay

Research Collection School Of Computing and Information Systems

We present our research into visual languages for animating sketches. Animation is a rich mode of communication that is currently accessible to few. Simple animation systems exist, but severely restrict the types of motion that can be represented. Our field studies are demonstrating that would-be animators need to coordinate many objects moving in a variety of ways. The visual language described here allows a variety of motions to be defined with hand gestures, and gives visual feedback for coordination of events. This may open up computerized communication to users who think in dynamic visual images.

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On The Security Of The Lee-Hwang Group-Oriented Undeniable Signature Schemes, Guilin Wang, Jianying Zhou, Robert H. Deng Sep 2004

On The Security Of The Lee-Hwang Group-Oriented Undeniable Signature Schemes, Guilin Wang, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

Undeniable signature is an intriguing concept introduced by Chaum and van Antwerpen at Crypto89. In 1999, Lee and Hwang presented two group-oriented undeniable signature schemes with a trusted center. Their schemes are natural generalizations of Chaums zero knowledge undeniable signature scheme proposed in 1990. However, we find that the Lee-Hwang schemes are insecure. In this paper, we demonstrate five effective attacks on their schemes: four of them are insider universal forgeries, in which one dishonest member (maybe colluding with a verifier) can get a valid signature on any chosen massage, and another attack allows a dishonest member to prevent honest …

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Proxy Signature Scheme With Multiple Original Signers For Wireless E-Commerce Applications, Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng Sep 2004

Proxy Signature Scheme With Multiple Original Signers For Wireless E-Commerce Applications, Guilin Wang, Feng Bao, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

In a proxy signature scheme, a user delegates his/her signing capability to another user in such a way that the latter can sign messages on behalf of the former. We propose an efficient and secure proxy signature scheme with multiple original signers. Our scheme is suitable for wireless electronic commerce applications, since the overheads of computation and communication are low. As an example, we present an electronic air ticket booking scheme for wireless customers.

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Rating Information Security Maturity, Arcot Desai Narasimhalu, Nagarajan Dayasindhu Aug 2004

Rating Information Security Maturity, Arcot Desai Narasimhalu, Nagarajan Dayasindhu

Research Collection School Of Computing and Information Systems

Most CEOs have difficulty relating to the information security investments in their companies. This article presents a summary of a the information security maturity model that the CEOs could use to determine the desired level of investments into information security infrastructure, tools and applications.

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Ica-Fx Features For Classification Of Singing Voice And Instrumental Sound, Tat-Wan Leung, Chong-Wah Ngo, Rynson W. H Lau Aug 2004

Ica-Fx Features For Classification Of Singing Voice And Instrumental Sound, Tat-Wan Leung, Chong-Wah Ngo, Rynson W. H Lau

Research Collection School Of Computing and Information Systems

This paper describes a new approach in locating the segments of singing voice in pop musical songs. Initially, GLR distance measure is employed to temporally detect the boundaries of singing voices and instrumental sounds. ICAFX is then adopted to extract the independent components of acoustic features for SVM classification. Experimental results indicate that ICA-FX can improve the classification performance by significantly reducing the independent components that are not related to class label information.

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Graph Based Image Matching, Hui Jiang, Chong-Wah Ngo Aug 2004

Graph Based Image Matching, Hui Jiang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Given two or more images, we can define different but related problems on pattern matching such as image registration, pattern detection and localization, and common pattern discovery. These problems have different levels of purpose and difficulties, as a result, often associate with different solutions. In this paper, we propose a novel approach to solve these problems under a unified framework based on graph matching. We first split the images into small blocks and represent each block as a node in a bipartite graph. A maximum weighted bipartite graph matching algorithm is then employed in an iterative way to find the …

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Novel Seed Selection For Multiple Objects Detection And Tracking, Zailiang Pan, Chong-Wah Ngo Aug 2004

Novel Seed Selection For Multiple Objects Detection And Tracking, Zailiang Pan, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper proposes a unified approach for initializing, detecting and tracking of multiple moving objects. Object initialization is achieved through novel seed selection which is adaptively activated, depending on the quality of tracking, to select the best possible frames along the temporal direction for object detection. EM algorithm is then employed to robustly segment and detect multiple objects in a selected frame. Each detected object is represented by an appearance-based model and mean shift tracking procedure is adopted to rapidly and effectively track the target objects.

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Group-Based Relevance Feedback With Support Vector Machine Ensembles, Steven C. H. Hoi, Michael R. Lyu Aug 2004

Group-Based Relevance Feedback With Support Vector Machine Ensembles, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Support vector machines (SVMs) have become one of the most promising techniques for relevance feedback in content-based image retrieval (CBIR). Typical SVM-based relevance feedback techniquessimply apply the strict binary classifications: positive (relevant) class and negative (irrelevant) class. However, in a real-world relevance feedback task, it is more reasonable and practical to assume the data come from multiple positive classes and one negative class. In order to formulate an effective relevance feedback algorithm, we propose a novel group-based relevance feedback scheme constructed with the SVM ensembles technique. Experiments are conducted to evaluate the performance of our proposed scheme and the traditional …

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Ltam: A Location-Temporal Authorization Model, Hai Yu, Ee Peng Lim Aug 2004

Ltam: A Location-Temporal Authorization Model, Hai Yu, Ee Peng Lim

Research Collection School Of Computing and Information Systems

This paper describes an authorization model for specifying access privileges of users who make requests to access a set of locations in a building or more generally a physical or virtual infrastructure. In the model, primitive locations can be grouped into composite locations and the connectivities among locations are represented in a multilevel location graph. Authorizations are defined with temporal constraints on the time to enter and leave a location and constraints on the number of times users can access a location. Access control enforcement is conducted by monitoring user movement and checking access requests against an authorization database. The …

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Exploiting Information Theory For Adaptive Mobility And Resource Management In Future Cellular Networks, Abhishek Roy, Sajal K. Das, Archan Misra Aug 2004

Exploiting Information Theory For Adaptive Mobility And Resource Management In Future Cellular Networks, Abhishek Roy, Sajal K. Das, Archan Misra

Research Collection School Of Computing and Information Systems

We utilize tools from information theory to develop adaptive algorithms for two key problems in cellular networks: location tracking and resource management. The use of information theory is motivated by the fundamental observation that overheads in many aspects of mobile computing can be traced to the randomness or uncertainty in an individual user's movement behavior. We present a model-independent information-theoretic approach for estimating and managing this uncertainty, and relate it to the entropy or information content of the user's movement process. Information-theoretic mobility management algorithms are very simple, yet reduce overhead by ∼80 percent in simulated scenarios by optimally adapting …

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Deformable Geometry Model Matching By Topological And Geometric Signatures, Kwok-Leung Tam, Rynson W.H. Law, Chong-Wah Ngo Aug 2004

Deformable Geometry Model Matching By Topological And Geometric Signatures, Kwok-Leung Tam, Rynson W.H. Law, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we present a novel method for efficient 3D model comparison. The method matches highly deformed models by comparing topological and geometric features. First, we propose “Bi-directional LSD analysis” to locate reliable topological points and rings. Second, based on these points and rings, a set of bounded regions are extracted as topological features. Third, for each bounded region, we capture additional spatial location, curvature and area distribution as geometric data. Fourth, to model the topological importance of each bounded region, we capture its effective area as weight. By using “Earth Mover Distance” as a distance measure between two …

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Packet-Loss Resilient Coding Scheme With Only Xor Operations, Gui Liang Feng, Robert H. Deng, Feng Bao Aug 2004

Packet-Loss Resilient Coding Scheme With Only Xor Operations, Gui Liang Feng, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Application of forward error correction to recover lost packets in higher layers of communication networks is receiving increasing attention. Most of the previous proposals for packet loss recovery use symbol-oriented Reed-Solomon codes operating in symbol erasure-correction mode. A Reed-Solomon code is optimal in the sense that it is maximal distance separable; however, the decoding speed of a Reed-Solomon code is slow since it involves operations over GF(2m) using lookup tables. A packet-oriented (n, k)/(m, l) packet-loss resilient code based on an (n, k) Reed-Solomon code over GF(2m) is given. The code accepts k-packet information sequences and encodes them into n-packet …

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High Accuracy Classification Of Eeg Signal, Wenjie Xu, Cuitai Guan, Chng Eng Siong, S. Ranganatha, Manoj Thulasidas, Jiankang Wu Aug 2004

High Accuracy Classification Of Eeg Signal, Wenjie Xu, Cuitai Guan, Chng Eng Siong, S. Ranganatha, Manoj Thulasidas, Jiankang Wu

Research Collection School Of Computing and Information Systems

Improving classification accuracy is a key issue to advancing brain computer interface (BCI) research from laboratory to real world applications. This article presents a high accuracy EEC signal classification method using single trial EEC signal to detect left and right finger movement. We apply an optimal temporal filter to remove irrelevant signal and subsequently extract key features from spatial patterns of EEG signal to perform classification. Specifically, the proposed method transforms the original EEG signal into a spatial pattern and applies the RBF feature selection method to generate robust feature. Classification is performed by the SVM and our experimental result …

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