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2006

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Articles 241 - 270 of 1262

Full-Text Articles in Computer Sciences

A Multi-Agent Framework For Testing Distributed Systems, Hany Elyamany, Miriam Capretz, Luiz Fernando Capretz Sep 2006

A Multi-Agent Framework For Testing Distributed Systems, Hany Elyamany, Miriam Capretz, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

Software testing is a very expensive and time consuming process. It can account for up to 50% of the total cost of the software development. Distributed systems make software testing a daunting task. The research described in this paper investigates a novel multi-agent framework for testing 3-tier distributed systems. This paper describes the framework architecture as well as the communication mechanism among agents in the architecture. Web-based application is examined as a case study to validate the proposed framework. The framework is considered as a step forward to automate testing for distributed systems in order to enhance their reliability within …

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On The Use Of Mutation Faults In Empirical Assessments Of Test Case Prioritization Techniques, Hyunsook Do, Gregg Rothermel Sep 2006

On The Use Of Mutation Faults In Empirical Assessments Of Test Case Prioritization Techniques, Hyunsook Do, Gregg Rothermel

School of Computing: Faculty Publications

Regression testing is an important activity in the software life cycle, but it can also be very expensive. To reduce the cost of regression testing, software testers may prioritize their test cases so that those which are more important, by some measure, are run earlier in the regression testing process. One potential goal of test case prioritization techniques is to increase a test suite’s rate of fault detection (how quickly, in a run of its test cases, that test suite can detect faults). Previous work has shown that prioritization can improve a test suite’s rate of fault detection, but the …

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Optical Image Blending For Underwater Mosaics, Fan Gu, Yuri Rzhanov Sep 2006

Optical Image Blending For Underwater Mosaics, Fan Gu, Yuri Rzhanov

Center for Coastal and Ocean Mapping

Typical problems for creation of consistent underwater mosaic are misalignment and inhomogeneous illumination of the image frames, which causes visible seams and consequently complicates post-processing of the mosaics such as object recognition and shape extraction. Two recently developed image blending methods were explored in the literature: "gradient domain stitching" and "graph-cut" method, and they allow for improvement of illumination inconsistency and "ghosting" effects, respectively. However, due to the specifics of underwater imagery, these two methods cannot be used within a straightforward manner. In this paper, a new improved blending algorithm is proposed based on these two methods. By comparing with …

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Experiments For Multibeam Backscatter Adjustments On The Noaa Ship Fairweather, Luciano E. Fonseca, Brian R. Calder Sep 2006

Experiments For Multibeam Backscatter Adjustments On The Noaa Ship Fairweather, Luciano E. Fonseca, Brian R. Calder

Center for Coastal and Ocean Mapping

A series of experiments were conducted to adjust and normalize the acoustic backscatter acquired by Reson 8111 and 8160 systems. The dependency of the backscatter on the receiver gain, transmit power, pulse width and acquisition mode was analyzed. Empirical beam patterns are calculated as the difference between the backscatter measured by the sonars and the expected backscatter. Expected acoustic backscatter is estimated based on a mathematical model.

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An Instance-Based Structured Object Oriented Method For Co-Analysis/Co-Design Of Concurrent Embedded Systems, Matt Ryan, Xiaoqing Frank Liu, Bruce M. Mcmillin, Ying Cheng, Sule Simsek Sep 2006

An Instance-Based Structured Object Oriented Method For Co-Analysis/Co-Design Of Concurrent Embedded Systems, Matt Ryan, Xiaoqing Frank Liu, Bruce M. Mcmillin, Ying Cheng, Sule Simsek

Computer Science Faculty Research & Creative Works

The current object-oriented class-based approaches to hardware/software co-analysis/co-design of embedded systems are limited in their abilities to properly capture the structure of individual instances of hardware and software components and their interactions. This paper discusses a methodology to extend a structured objectoriented hardware/software co-design methodology based on the High Order Object-oriented Modeling Technique (HOOMT) to incorporate instance-based object and behavioral models. The instance-based structured object-oriented methodology will enable description of a system's structure based on individual instances of hardware and software components and specification of the interactions among them. In addition, lattices are introduced to specify the concurrent behavior of …

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New Tracking Filter Algorithm Using Input Parameter Estimation, Corey M. Broussard Sep 2006

New Tracking Filter Algorithm Using Input Parameter Estimation, Corey M. Broussard

Theses and Dissertations

A new method for the design of tracking filters for maneuvering targets, based on kinematic models and input signals estimation, is developed. The input signal's level, u is considered a continuous variable and consequently the input estimation problem is posed as a purely parameter estimation problem. Moreover, the application of the new tracking filter algorithm is not contingent on distinguishing maneuvering and non-maneuvering targets, and does not require the detection of maneuver onset. The filter will automatically detect the onset of a maneuver. Furthermore, an estimate of the target's acceleration is also obtained with reasonable precision. This opens the door …

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Optimizing The Replication Of Multi-Quality Web Applications Using Aco And Wolf, Judson C. Dressler Sep 2006

Optimizing The Replication Of Multi-Quality Web Applications Using Aco And Wolf, Judson C. Dressler

Theses and Dissertations

This thesis presents the adaptation of Ant Colony Optimization to a new NP-hard problem involving the replication of multi-quality database-driven web applications (DAs) by a large application service provider (ASP). The ASP must assign DA replicas to its network of heterogeneous servers so that user demand is satisfied and replica update loads are minimized. The algorithm proposed, AntDA, for solving this problem is novel in several respects: ants traverse a bipartite graph in both directions as they construct solutions, pheromone is used for traversing from one side of the bipartite graph to the other and back again, heuristic edge values …

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Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli Sep 2006

Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli

Theses and Dissertations

This research involves the design, implementation, and testing of a high-speed, real-time kinematic, precise differential GPS positioning system for use in airborne applications such as automated aerial-refueling and close formation flying. Although many of the current ambiguity resolution techniques use the residuals from the least squares position estimation to determine the true ambiguity set, this thesis presents a novel approach to the ambiguity resolution problem, called the minimum indicator. Instead of assuming the ambiguity set with the lowest residuals is the true set, other special characteristics of the residuals are examined. This increases the confidence that the algorithm has selected …

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Tools And Algorithms To Advance Interactive Intrusion Analysis Via Machine Learning And Information Retrieval, Javed Aslam, Sergey Bratus, Virgil Pavlu Sep 2006

Tools And Algorithms To Advance Interactive Intrusion Analysis Via Machine Learning And Information Retrieval, Javed Aslam, Sergey Bratus, Virgil Pavlu

Computer Science Technical Reports

We consider typical tasks that arise in the intrusion analysis of log data from the perspectives of Machine Learning and Information Retrieval, and we study a number of data organization and interactive learning techniques to improve the analyst's efficiency. In doing so, we attempt to translate intrusion analysis problems into the language of the abovementioned disciplines and to offer metrics to evaluate the effect of proposed techniques. The Kerf toolkit contains prototype implementations of these techniques, as well as data transformation tools that help bridge the gap between the real world log data formats and the ML and IR data …

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Semantic Interoperability Of Web Services - Challenges And Experiences, Meenakshi Nagarajan, Kunal Verma, Amit P. Sheth, John A. Miller, Jonathan Lathem Sep 2006

Semantic Interoperability Of Web Services - Challenges And Experiences, Meenakshi Nagarajan, Kunal Verma, Amit P. Sheth, John A. Miller, Jonathan Lathem

Kno.e.sis Publications

With the rising popularity of Web services, both academia and industry have invested considerably in Web service description standards, discovery, and composition techniques. The standards based approach utilized by Web services has supported interoperability at the syntax level. However, issues of structural and semantic heterogeneity between messages exchanged by Web services are far more complex and crucial to interoperability. It is for these reasons that we recognize the value that schema/data mappings bring to Web service descriptions. In this paper, we examine challenges to interoperability; classify the types of heterogeneities that can occur between interacting services and present a possible …

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Optimal Adaptation In Web Processes With Coordination Constraints, Kunal Verma, Prashant Doshi, Karthik Gomadam, John A. Miller, Amit P. Sheth Sep 2006

Optimal Adaptation In Web Processes With Coordination Constraints, Kunal Verma, Prashant Doshi, Karthik Gomadam, John A. Miller, Amit P. Sheth

Kno.e.sis Publications

We present methods for optimally adapting Web processes to exogenous events while preserving inter-service constraints that necessitate coordination. For example, in a supply chain process, orders placed by a manufacturer may get delayed in arriving. In response to this event, the manufacturer has the choice of either waiting out the delay or changing the supplier. Additionally, there may be compatibility constraints between the different orders, thereby introducing the problem of coordination between them if the manufacturer chooses to change the suppliers. We focus on formulating the decision making models of the managers, who must adapt to external events while satisfying …

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Flexible Querying Of Xml Documents, Krishnaprasad Thirunarayan, Trivikram Immaneni Sep 2006

Flexible Querying Of Xml Documents, Krishnaprasad Thirunarayan, Trivikram Immaneni

Kno.e.sis Publications

Text search engines are inadequate for indexing and searching XML documents because they ignore metadata and aggregation structure implicit in the XML documents. On the other hand, the query languages supported by specialized XML search engines are very complex. In this paper, we present a simple yet flexible query language, and develop its semantics to enable intuitively appealing extraction of relevant fragments of information while simultaneously falling back on retrieval through plain text search if necessary. We also present a simple yet robust relevance ranking for heterogeneous document-centric XML.

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Digital Image Ballistics From Jpeg Quantization, Hany Farid Sep 2006

Digital Image Ballistics From Jpeg Quantization, Hany Farid

Computer Science Technical Reports

Most digital cameras export images in the JPEG file format. This lossy compression scheme employs a quantization table that controls the amount of compression achieved. Different cameras typically employ different tables. A comparison of an image's quantization scheme to a database of known cameras affords a simple technique for confirming or denying an image's source. Similarly, comparison to a database of photo-editing software can be used in a forensic setting to determine if an image was edited after its original recording.

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An Event-Driven Approach To Computerizing Clinical Guidelines Using Xml, Bing Wu, Essam Mansour, Kudakwashe Dube, Jianxin Li Sep 2006

An Event-Driven Approach To Computerizing Clinical Guidelines Using Xml, Bing Wu, Essam Mansour, Kudakwashe Dube, Jianxin Li

Conference Papers

Clinical events form the basis of patient care practice. Their computerization is an important aid to the work of clinicians. Clinical guidelines or protocols direct clinicians and patients on when and how to handle clinical problems. Thus, clinical guidelines are an encapsulation of clinical events. Hence, an event-driven approach to computerizing the management of clinical guidelines is worthy of investigation. In our framework, called SpEM, the main clinical guideline management dimensions are specification, execution, and manipulation. This paper presents an event-driven approach, within the context of the SpEM framework, to manage clinical guidelines. The event-driven approach is based on the …

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Path-Sensitive Inference Of Function Precedence Protocols, Murali Krishna Ramanathan, Ananth Y. Grama, Suresh Jagannathan Sep 2006

Path-Sensitive Inference Of Function Precedence Protocols, Murali Krishna Ramanathan, Ananth Y. Grama, Suresh Jagannathan

Department of Computer Science Technical Reports

No abstract provided.

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Self-Positioning Smart Buoys, The 'Un-Buoy' Solution: Logistic Considerations Using Autonomous Surface Craft Technology And Improved Communications Infrastructure, Joseph A. Curcio, Philip A. Mcgillivary, Kevin Fall, Andrew Maffei, Kurt Schwehr, Bob Twiggs, Chris Kitts, Phil Ballou Sep 2006

Self-Positioning Smart Buoys, The 'Un-Buoy' Solution: Logistic Considerations Using Autonomous Surface Craft Technology And Improved Communications Infrastructure, Joseph A. Curcio, Philip A. Mcgillivary, Kevin Fall, Andrew Maffei, Kurt Schwehr, Bob Twiggs, Chris Kitts, Phil Ballou

Center for Coastal and Ocean Mapping

Moored buoys have long served national interests, but incur high development, construction, installation, and maintenance costs. Buoys which drift off-location can pose hazards to mariners, and in coastal waters may cause environmental damage. Moreover, retrieval, repair and replacement of drifting buoys may be delayed when data would be most useful. Such gaps in coastal buoy data can pose a threat to national security by reducing maritime domain awareness. The concept of self-positioning buoys has been advanced to reduce installation cost by eliminating mooring hardware. We here describe technology for operation of reduced cost self-positioning buoys which can be used in …

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Mining Rdf Metadata For Generalized Association Rules, Tao Jiang, Ah-Hwee Tan Sep 2006

Mining Rdf Metadata For Generalized Association Rules, Tao Jiang, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

In this paper, we present a novel frequent generalized pattern mining algorithm, called GP-Close, for mining generalized associations from RDF metadata. To solve the over-generalization problem encountered by existing methods, GP-Close employs the notion of generalization closure for systematic over-generalization reduction. Empirical experiments conducted on real world RDF data sets show that our method can substantially reduce pattern redundancy and perform much better than the original generalized association rule mining algorithm Cumulate in term of time efficiency.

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Wireless Indoor Positioning System With Enhanced Nearest Neighbors In Signal Space Algorithm, Quang Tran, Juki Wirawan Tantra, Ah-Hwee Tan, Ah-Hwee Tan, Kin-Choong Yow, Dongyu Qiu Sep 2006

Wireless Indoor Positioning System With Enhanced Nearest Neighbors In Signal Space Algorithm, Quang Tran, Juki Wirawan Tantra, Ah-Hwee Tan, Ah-Hwee Tan, Kin-Choong Yow, Dongyu Qiu

Research Collection School Of Computing and Information Systems

With the rapid development and wide deployment of wireless Local Area Networks (WLANs), WLAN-based positioning system employing signal-strength-based technique has become an attractive solution for location estimation in indoor environment. In recent years, a number of such systems has been presented, and most of the systems use the common Nearest Neighbor in Signal Space (NNSS) algorithm. In this paper, we propose an enhancement to the NNSS algorithm. We analyze the enhancement to show its effectiveness. The performance of the enhanced NNSS algorithm is evaluated with different values of the parameters. Based on the performance evaluation and analysis, we recommend some …

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Discovering Image-Text Associations For Cross-Media Web Information Fusion, Tao Jiang, Ah-Hwee Tan Sep 2006

Discovering Image-Text Associations For Cross-Media Web Information Fusion, Tao Jiang, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

The diverse and distributed nature of the information published on the World Wide Web has made it difficult to collate and track information related to specific topics. Whereas most existing work on web information fusion has focused on multiple document summarization, this paper presents a novel approach for discovering associations between images and text segments, which subsequently can be used to support cross-media web content summarization. Specifically, we employ a similarity-based multilingual retrieval model and adopt a vague transformation technique for measuring the information similarity between visual features and textual features. The experimental results on a terrorist domain document set …

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Masking Page Reference Patterns In Encryption Databases On Untrusted Storage, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan Sep 2006

Masking Page Reference Patterns In Encryption Databases On Untrusted Storage, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

To support ubiquitous computing, the underlying data have to be persistent and available anywhere-anytime. The data thus have to migrate from devices that are local to individual computers, to shared storage volumes that are accessible over open network. This potentially exposes the data to heightened security risks. In particular, the activity on a database exhibits regular page reference patterns that could help attackers learn logical links among physical pages and then launch additional attacks. We propose two countermeasures to mitigate the risk of attacks initiated through analyzing the shared storage server’s activity for those page patterns. The first countermeasure relocates …

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Continuous Nearest Neighbor Monitoring In Road Networks, Kyriakos Mouratidis, Man Lung Yiu, Dimitris Papadias, Nikos Mamoulis Sep 2006

Continuous Nearest Neighbor Monitoring In Road Networks, Kyriakos Mouratidis, Man Lung Yiu, Dimitris Papadias, Nikos Mamoulis

Research Collection School Of Computing and Information Systems

Recent research has focused on continuous monitoring of nearest neighbors (NN) in highly dynamic scenarios, where the queries and the data objects move frequently and arbitrarily. All existing methods, however, assume the Euclidean distance metric. In this paper we study k-NN monitoring in road networks, where the distance between a query and a data object is determined by the length of the shortest path connecting them. We propose two methods that can handle arbitrary object and query moving patterns, as well as °uctuations of edge weights. The ¯rst one maintains the query results by processing only updates that may invalidate …

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Three Architectures For Trusted Data Dissemination In Edge Computing, Shen-Tat Goh, Hwee Hwa Pang, Robert H. Deng, Feng Bao Sep 2006

Three Architectures For Trusted Data Dissemination In Edge Computing, Shen-Tat Goh, Hwee Hwa Pang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Edge computing pushes application logic and the underlying data to the edge of the network, with the aim of improving availability and scalability. As the edge servers are not necessarily secure, there must be provisions for users to validate the results—that values in the result tuples are not tampered with, that no qualifying data are left out, that no spurious tuples are introduced, and that a query result is not actually the output from a different query. This paper aims to address the challenges of ensuring data integrity in edge computing. We study three schemes that enable users to check …

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Cuhk At Imageclef 2005: Cross-Language And Cross Media Image Retrieval, Steven Hoi, Jianke Zhu, Michael R. Lyu Sep 2006

Cuhk At Imageclef 2005: Cross-Language And Cross Media Image Retrieval, Steven Hoi, Jianke Zhu, Michael R. 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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Rights Protection For Data Cubes, Jie Guo, Yingjiu Li, Robert H. Deng, Kefei Chen Sep 2006

Rights Protection For Data Cubes, Jie Guo, Yingjiu Li, Robert H. Deng, Kefei Chen

Research Collection School Of Computing and Information Systems

We propose a rights protection scheme for data cubes. The scheme embeds ownership information by modifying a set of selected cell values. The embedded message will not affect the usefulness of data cubes in the sense that the sum queries at any aggregation level are not affected. At the same time, the errors introduced to individual cell values are under control. The embedded message can be detected with a high probability even in the presence of typical data cube attacks. The proposed scheme can thus be used for protecting data cubes from piracy in an open, distributed environment.

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Practical Private Data Matching Deterrent To Spoofing Attacks, Yanjiang Yang, Robert H. Deng, Feng Bao Sep 2006

Practical Private Data Matching Deterrent To Spoofing Attacks, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Private data matching between the data sets of two potentially distrusted parties has a wide range of applications. However, existing solutions have substantial weaknesses and do not meet the needs of many practical application scenarios. In particular, practical private data matching applications often require discouraging the matching parties from spoofing their private inputs. In this paper, we address this challenge by forcing the matching parties to "escrow" the data they use for matching to an auditorial agent, and in the "after-the-fact" period, they undertake the liability to attest the genuineness of the escrowed data.

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Disclosure Analysis For Two-Way Contingency Tables, Haibing Lu, Yingjiu Li, Xintao Wu Sep 2006

Disclosure Analysis For Two-Way Contingency Tables, Haibing Lu, Yingjiu Li, Xintao Wu

Research Collection School Of Computing and Information Systems

Disclosure analysis in two-way contingency tables is important in categorical data analysis. The disclosure analysis concerns whether a data snooper can infer any protected cell values, which contain privacy sensitive information, from available marginal totals (i.e., row sums and column sums) in a two-way contingency table. Previous research has been targeted on this problem from various perspectives. However, there is a lack of systematic definitions on the disclosure of cell values. Also, no previous study has been focused on the distribution of the cells that are subject to various types of disclosure. In this paper, we define four types of …

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Multi-Learner Based Recursive Supervised Training, Laxmi R. Iyer, Kiruthika Ramanathan, Sheng-Uei Guan Sep 2006

Multi-Learner Based Recursive Supervised Training, Laxmi R. Iyer, Kiruthika Ramanathan, Sheng-Uei Guan

Research Collection School Of Computing and Information Systems

In this paper, we propose the multi-learner based recursive supervised training (MLRT) algorithm, which uses the existing framework of recursive task decomposition, by training the entire dataset, picking out the best learnt patterns, and then repeating the process with the remaining patterns. Instead of having a single learner to classify all datasets during each recursion, an appropriate learner is chosen from a set of three learners, based on the subset of data being trained, thereby avoiding the time overhead associated with the genetic algorithm learner utilized in previous approaches. In this way MLRT seeks to identify the inherent characteristics of …

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Multi-Learner Based Recursive Supervised Training, Laxmi R. Iyer, Kiruthika Ramanathan, Sheng-Uei Guan Sep 2006

Multi-Learner Based Recursive Supervised Training, Laxmi R. Iyer, Kiruthika Ramanathan, Sheng-Uei Guan

Research Collection School Of Computing and Information Systems

In this paper, we propose the multi-learner based recursive supervised training (MLRT) algorithm, which uses the existing framework of recursive task decomposition, by training the entire dataset, picking out the best learnt patterns, and then repeating the process with the remaining patterns. Instead of having a single learner to classify all datasets during each recursion, an appropriate learner is chosen from a set of three learners, based on the subset of data being trained, thereby avoiding the time overhead associated with the genetic algorithm learner utilized in previous approaches. In this way MLRT seeks to identify the inherent characteristics of …

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Human-Computer Interaction Research In The Management Information Systems Discipline, Fiona Fui-Hoon Nah, Ping Zhang, Scott Mccoy, Munyong Yi Sep 2006

Human-Computer Interaction Research In The Management Information Systems Discipline, Fiona Fui-Hoon Nah, Ping Zhang, Scott Mccoy, Munyong Yi

Research Collection School Of Computing and Information Systems

No abstract provided.

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Minimum Latency Broadcasting In Multi-Radio Multi-Channel Multi-Rate Wireless Meshes, Junaid Qadir, Archan Misra, Chun Tung Chou Sep 2006

Minimum Latency Broadcasting In Multi-Radio Multi-Channel Multi-Rate Wireless Meshes, Junaid Qadir, Archan Misra, Chun Tung Chou

Research Collection School Of Computing and Information Systems

We address the problem of minimizing the worst-case broadcast delay in multi-radio multi-channel multi-rate (MR2-MC) wireless mesh networks (WMN). The problem of 'efficient' broadcast in such networks is especially challenging due to the numerous interrelated decisions that have to be made. The multi-rate transmission capability of WMN nodes, interference between wireless transmissions, and the hardness of optimal channel assignment adds complexity to our considered problem. We present four heuristic algorithms to solve the minimum latency broadcast problem for such settings and show that the 'best' performing algorithms usually adapt themselves to the available radio interfaces and channels. We also study …

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