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2008

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Articles 241 - 270 of 1335

Full-Text Articles in Computer Sciences

Model Checking Csp Revisited: Introducing A Process Analysis Toolkit, Jun Sun, Yang Liu, Jin Song Dong Oct 2008

Model Checking Csp Revisited: Introducing A Process Analysis Toolkit, Jun Sun, Yang Liu, Jin Song Dong

Research Collection School Of Computing and Information Systems

FDR, initially introduced decades ago, is the de facto analyzer for Communicating Sequential Processes (CSP). Model checking techniques have been evolved rapidly since then. This paper describes PAT, i.e., a process analysis toolkit which complements FDR in several aspects. PAT is designed to analyze event-based compositional system models specified using CSP as well as shared variables and asynchronous message passing. It supports automated refinement checking, model checking of LTL extended with events, etc. In this paper, we highlight how partial order reduction is applied to improve refinement checking in PAT. Experiment results show that PAT outperforms FDR in some cases.


Determining The Number Of Bp Neural Network Hidden Layer Units, Huayu Shen, Zhaoxia Wang, Chengyao Gao, Juan Qin, Fubin Yao, Wei Xu Oct 2008

Determining The Number Of Bp Neural Network Hidden Layer Units, Huayu Shen, Zhaoxia Wang, Chengyao Gao, Juan Qin, Fubin Yao, Wei Xu

Research Collection School Of Computing and Information Systems

This paper proposed an improved method to contrapose the problem which is difficult to determine the number of BP neural network hidden layer units. it is proved that the method is efficeient in reducing the frequency of the test through experients, and improves the efficiency of determining the best number of hidden units, which is more valuable in the applications.


Link Layer Multicast Using Smart Antennas: No Client Left Behind, Souvik Sen, Jie Xiong, Rahul Ghosh, Romit Roy Choudhury Oct 2008

Link Layer Multicast Using Smart Antennas: No Client Left Behind, Souvik Sen, Jie Xiong, Rahul Ghosh, Romit Roy Choudhury

Research Collection School Of Computing and Information Systems

Wireless link layer multicast is an important service primitive for emerging applications, such as live video, streaming audio, and other content telecasts. The broadcast nature of the wireless channel is amenable to multicast because a single packet transmission may be received by all clients in the multicast group. However, in view of diverse channel conditions at different clients, the rate of such a transmission is bottlenecked by the rate of the weakest client. Multicast throughput degrades severely. Attempts to increase the data rate result in lower reliability and higher unfairness. This paper utilizes smart beamforming antennas to improve multicast performance …


Using Trusted Computing Technology To Facilitate Security Enforcement In Wireless Sensor Networks, Yanjiang Yang, Robert H. Deng, Feng Bao, Jianying Zhou Oct 2008

Using Trusted Computing Technology To Facilitate Security Enforcement In Wireless Sensor Networks, Yanjiang Yang, Robert H. Deng, Feng Bao, Jianying Zhou

Research Collection School Of Computing and Information Systems

Security enforcement in wireless sensor networks is by no means an easy task, due to the inherent resource-constrained nature of sensor nodes. To facilitate security enforcement, we propose to incorporate more powerful high-end Security Enforcement Facilitators (SEFs) into wireless sensor networks. In particular, the SEFs are equipped with TCG-compliant Trusted Platform Modules (TPMs) to protect cryptographic secrets, perform authenticated booting and attest their platform state to a remote base station.As such, the SEFs act as online trusted third parties toeffectively monitor the states of sensor nodes, help in keymanagement, simplify secure routing, and facilitate accesscontrol.


Ontology Enhanced Web Image Retrieval: Aided By Wikipedia And Spreading Activation Theory, Huan Wang, Xing Jiang, Liang-Tien Chia, Ah-Hwee Tan Oct 2008

Ontology Enhanced Web Image Retrieval: Aided By Wikipedia And Spreading Activation Theory, Huan Wang, Xing Jiang, Liang-Tien Chia, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Ontology, as an efective approach to bridge the semantic gap in various domains, has attracted a lot of interests from multimedia researchers. Among the numerous possibilities enabled by ontology, we are particularly interested in exploiting ontology for a better understanding of media task (particularly, images) on the World Wide Web. To achieve our goal, two open issues are inevitably involved: 1) How to avoid the tedious manual work for ontology construction? 2) What are the effective inference models when using an ontology? Recent works about ontology learned from Wikipedia has been reported in conferences targeting the areas of knowledge management …


Ontology-Based Visual Word Matching For Near-Duplicate Retrieval, Yu-Gang Jiang, Chong-Wah Ngo Oct 2008

Ontology-Based Visual Word Matching For Near-Duplicate Retrieval, Yu-Gang Jiang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper proposes a novel approach to exploit the ontological relationship of visual words by linguistic reasoning. A visual word ontology is constructed to facilitate the rigorous evaluation of linguistic similarity across visual words. The linguistic similarity measurement enables cross-bin matching of visual words, compromising the effectiveness and speed of conventional keypoint matching and bag-of-word approaches. A constraint EMD is proposed and experimented to efficiently match visual words. Empirical findings indicate that the proposed approach offers satisfactory performance to near-duplicate retrieval, while still enjoying the merit of speed efficiency compared with other techniques.


Video Event Detection Using Motion Relativity And Visual Relatedness, Feng Wang, Yu-Gang Jiang, Chong-Wah Ngo Oct 2008

Video Event Detection Using Motion Relativity And Visual Relatedness, Feng Wang, Yu-Gang Jiang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Event detection plays an essential role in video content analysis. However, the existing features are still weak in event detection because: i) most features just capture what is involved in an event or how the event evolves separately, and thus cannot completely describe the event; ii) to capture event evolution information, only motion distribution over the whole frame is used which proves to be noisy in unconstrained videos; iii) the estimated object motion is usually distorted by camera movement. To cope with these problems, in this paper, we propose a new motion feature, namely Expanded Relative Motion Histogram of Bag-ofVisual-Words …


Spatio-Temporal Efficiency In A Taxi Dispatch System, Darshan Santani, Rajesh Krishna Balan, C. Jason Woodard Oct 2008

Spatio-Temporal Efficiency In A Taxi Dispatch System, Darshan Santani, Rajesh Krishna Balan, C. Jason Woodard

Research Collection School Of Computing and Information Systems

In this paper, we present an empirical analysis of the GPS-enabled taxi dispatch system used by the world’s second largest land transportation company. We first summarize the collective dynamics of the more than 6,000 taxicabs in this fleet. Next, we propose a simple method for evaluating the efficiency of the system over a given period of time and geographic zone. Our method yields valuable insights into system performance—in particular, revealing significant inefficiencies that should command the attention of the fleet operator. For example, despite the state of the art dispatching system employed by the company, we find imbalances in supply …


Spreadsheet Data Resampling For Monte-Carlo Simulation, Thin Yin Leong, Wee Leong Lee Oct 2008

Spreadsheet Data Resampling For Monte-Carlo Simulation, Thin Yin Leong, Wee Leong Lee

Research Collection School Of Computing and Information Systems

The pervasiveness of spreadsheets software resulted in its increased application as a simulation tool for business analysis. Random values generation supporting such evaluations using spreadsheets are simple and yet powerful. However, the typical approach to Monte-Carlo simulations, which is what simulations with stochasticity are called, requires significant amount of time to be spent on data collection, data collation, and distribution function fitting. In fact, the latter can be overwhelming for undergraduate students to learn and do properly in a short time. Resampling eliminates both the need to fit distributions to the sample data, and to perform the ensuing tests of …


Engineering Management Framework In Support Of Modeling & Simulation Application For Domain Specific Procurement, Thomas Guy Litwin Oct 2008

Engineering Management Framework In Support Of Modeling & Simulation Application For Domain Specific Procurement, Thomas Guy Litwin

Engineering Management & Systems Engineering Theses & Dissertations

A strategic process is desirable for project-based organizations in order for them to be efficient and effective when developing Modeling & Simulation (M&S) systems. This thesis proposes an overarching process that combines traditional M&S and Engineering Management methodologies in a new framework to support M&S organizations during the procurement process.

This thesis proposes both a Strategic Project Management Process (SPMP) and a systems engineering process for M&S federation development projects. The systems engineering process utilizes the artifacts of Model Driven Architecture (MDA) to support building M&S federations driven by operational requirements. Detailed research of this systems engineering process revealed a …


The Development Of Genetic Algorithm For The Prediction Of Ship Motion From Wave Radar Data, Sumanth Tirumala Vangipuram Oct 2008

The Development Of Genetic Algorithm For The Prediction Of Ship Motion From Wave Radar Data, Sumanth Tirumala Vangipuram

Electrical & Computer Engineering Theses & Dissertations

Genetic Algorithms represent a model of natural process based on the Darwinian principle of evolution. Genetic algorithms are used to solve optimization problems by generating a set of possible solutions and determining which of these solutions most closely match the desired result. The Genetic Algorithm (GA) initially generates a random set of possible solutions, or populations, determines which members of the population are most desirable, and calculates better solutions by implementing genetic operations such as reproduction, cloning, and mutation. Problems where the evaluation of a solution is computationally simple enable the GA to search a vast search space. One of …


Masthead Sep 2008

Masthead

Journal of Digital Forensics, Security and Law

No abstract provided.


Front Matter Sep 2008

Front Matter

Journal of Digital Forensics, Security and Law

No abstract provided.


Back Matter Sep 2008

Back Matter

Journal of Digital Forensics, Security and Law

No abstract provided.


Word Sense Disambiguation In Biomedical Ontologies With Term Co-Occurrence Analysis And Document Clustering, Bill Andreopoulos, Dimitra Alexopoulou, Michael Schroeder Sep 2008

Word Sense Disambiguation In Biomedical Ontologies With Term Co-Occurrence Analysis And Document Clustering, Bill Andreopoulos, Dimitra Alexopoulou, Michael Schroeder

Faculty Publications, Computer Science

With more and more genomes being sequenced, a lot of effort is devoted to their annotation with terms from controlled vocabularies such as the GeneOntology. Manual annotation based on relevant literature is tedious, but automation of this process is difficult. One particularly challenging problem is word sense disambiguation. Terms such as |development| can refer to developmental biology or to the more general sense. Here, we present two approaches to address this problem by using term co-occurrences and document clustering. To evaluate our method we defined a corpus of 331 documents on development and developmental biology. Term co-occurrence analysis achieves an …


Autonomous And Intelligent Radio Switching For Heterogeneous Wireless Networks, Qiuyi Duan, Charles D. Knutson, Lei Wang, Daniel Zappala Sep 2008

Autonomous And Intelligent Radio Switching For Heterogeneous Wireless Networks, Qiuyi Duan, Charles D. Knutson, Lei Wang, Daniel Zappala

Faculty Publications

As wireless devices continue to become more prevalent, heterogeneous wireless networks - in which communicating devices have at their disposal multiple types of radios - will become the norm. Communication between nodes in these networks ought to be as simple as possible; they should be able to seamlessly switch between different radios and network stacks on the fly in order to better serve the user. To make this a possibility, we consider the challenging problems of when two communicating devices should decide to switch to a different radio, and which radio they should choose. We design an Autonomous and Intelligent …


Application Of Optimization Techniques To Spectrally Modulated, Spectrally Encoded Waveform Design, Todd W. Beard Sep 2008

Application Of Optimization Techniques To Spectrally Modulated, Spectrally Encoded Waveform Design, Todd W. Beard

Theses and Dissertations

A design process is demonstrated for a coexistent scenario containing Spectrally Modulated, Spectrally Encoded (SMSE) and Direct Sequence Spread Spectrum (DSSS) signals. Coexistent SMSE-DSSS designs are addressed under both perfect and imperfect DSSS code tracking conditions using a non-coherent delay-lock loop (DLL). Under both conditions, the number of SMSE subcarriers and subcarrier spacing are the optimization variables of interest. For perfect DLL code tracking conditions, the GA and RSM optimization processes are considered independently with the objective function being end-to-end DSSS bit error rate. A hybrid GA-RSM optimization process is used under more realistic imperfect DLL code tracking conditions. In …


Development Of A Workflow For The Comparison Of Classification Techniques, Zanifa Omary Sep 2008

Development Of A Workflow For The Comparison Of Classification Techniques, Zanifa Omary

Masters

As the interest in machine learning and data mining springs up, the problem of how to assess learning algorithms and compare classifiers become more pressing. This has been associated with the lack of comprehensive and complete workflow depending on the project scale to provide guidance to its users. This means the success or failure of the project can be highly dependent on the person or team carrying it. The standard practice adopted by many researchers and experimenters has been to follow steps or phases from existing workflows such as CRISP-DM, KDD and SASSEMMA. However, as machine learning and data mining …


Implementing Continuation Marks In Javascript, John Clements, Ayswarya Sundaram, David Herman Sep 2008

Implementing Continuation Marks In Javascript, John Clements, Ayswarya Sundaram, David Herman

Computer Science and Software Engineering

MzScheme’s continuation marks provide a flexible mechanism for implementing a number of useful language features and tools. We demonstrate the simplicity and utility of continuation marks by adapting them for JavaScript as frame-based stack marks using the Rhino implementation, showing a simple model of their behavior, and using them to build a toy debugger. Along the way, we discover a few interesting things. First, it requires some thinking—but not much code—to add continuation marks to JavaScript. Second, coupling tail-calling with the “return” of statement-based languages leads to some interesting problems in formulating a semantics. Third, building a debugger based on …


T-Plausibility: Semantic Preserving Text Sanitization, Wei Jiang, Mummoorthy Murugesan, Chris Clifton, Luo Si Sep 2008

T-Plausibility: Semantic Preserving Text Sanitization, Wei Jiang, Mummoorthy Murugesan, Chris Clifton, Luo Si

Department of Computer Science Technical Reports

No abstract provided.


Lzfuzz: A Fast Compression-Based Fuzzer For Poorly Documented Protocols, Sergey Bratus, Axel Hansen, Anna Shubina Sep 2008

Lzfuzz: A Fast Compression-Based Fuzzer For Poorly Documented Protocols, Sergey Bratus, Axel Hansen, Anna Shubina

Computer Science Technical Reports

Real-world infrastructure offers many scenarios where protocols (and other details) are not released due to being considered too sensitive or for other reasons. This situation makes it hard to apply fuzzing techniques to test their security and reliability, since their full documentation is only available to their developers, and domain developer expertise does not necessarily intersect with fuzz-testing expertise (nor deployment responsibility). State-of-the-art fuzzing techniques, however, work best when protocol specifications are available. Still, operators whose networks include equipment communicating via proprietary protocols should be able to reap the benefits of fuzz-testing them. In particular, administrators should be able to …


Proactive Role Discovery In Mediator-Free Environments, Mohamed Shehab, Elisa Bertino, Arif Ghafoor Sep 2008

Proactive Role Discovery In Mediator-Free Environments, Mohamed Shehab, Elisa Bertino, Arif Ghafoor

Cyber Center Publications

The rapid proliferation of Internet and related technologies has created tremendous possibilities for the interoperability between domains in distributed environments. Interoperability does not come easy at it opens the way for several security and privacy breaches. In this paper, we focus on the distributed authorization discovery problem that is crucial to enable secure inter- operability. We present a distributed access path discovery framework that does not require a centralized mediator. We propose and verify a role routing protocol that propagates secure, minimal-length paths to reachable roles in other domains. Finally, we present experimental results of our role routing protocol based …


An M-Sequence Based Steganography Model For Voice Over Ip, Lei Tian, Ke Zhou, Hong Jiang, Jin Liu, Yongfeng Huang, Dan Feng Sep 2008

An M-Sequence Based Steganography Model For Voice Over Ip, Lei Tian, Ke Zhou, Hong Jiang, Jin Liu, Yongfeng Huang, Dan Feng

School of Computing: Technical Reports

Differing from applying steganography on storage cover media, steganography on Voice over IP (VoIP) must often delicately balance between providing adequate security and maintaining low latency for real-time services. This paper presents a novel real-time steganography model for VoIP that aims at providing good security for secret messages without sacrificing real-time performance. We achieve this goal by employing the well-known least-significant-bits (LSB) substitution approach to provide a reasonable tradeoff between the adequate information hiding requirement (good security and sufficient capacity) and the low latency requirement for VoIP. Further, we incorporate the m-sequence technique to eliminate the correlation among secret messages …


Segmenting Brain Tumors Using Pseudo-Conditional Random Fields, Chi-Hoon Lee, Shaojun Wang, Albert Murtha, Matthew R.G. Brown, Russell Greiner Sep 2008

Segmenting Brain Tumors Using Pseudo-Conditional Random Fields, Chi-Hoon Lee, Shaojun Wang, Albert Murtha, Matthew R.G. Brown, Russell Greiner

Kno.e.sis Publications

Locating Brain tumor segmentation within MR (magnetic resonance) images is integral to the treatment of brain cancer. This segmentation task requires classifying each voxel as either tumor or non-tumor, based on a description of that voxel. Unfortunately, standard classifiers, such as Logistic Regression (LR) and Support Vector Machines (SVM), typically have limited accuracy as they treat voxels as independent and identically distributed (iid). Approaches based on random fields, which are able to incorporate spatial constraints, have recently been applied to brain tumor segmentation with notable performance improvement over iid classifiers. However, previous random field systems involved computationally intractable …


On Incorporating Learning Theories To Simulate A Computer-Supported Collaborative Learning Environment, Nobel Khandaker, Leen-Kiat Soh Sep 2008

On Incorporating Learning Theories To Simulate A Computer-Supported Collaborative Learning Environment, Nobel Khandaker, Leen-Kiat Soh

School of Computing: Technical Reports

The success of a computer-supported collaborative learning (CSCL) environment in improving student knowledge depends on factors like student attributes (e.g., ability and motivation) and elements of the CSCL environment (e.g., group size and group formation). Better understanding of the individual and combined effects of these factors on the learning outcome of students would help: (1) researchers design better CSCL systems and (2) teachers make better decisions while carrying out CSCL sessions. To aid the researchers and teachers, we have used the observations collected and derived from published theories on individual, peer-based, and collaborative learning to design SimCoL, a multiagent-based tool …


Automatic Failure Inducing Chain Computation Through Aligned Execution Comparison, William N. Sumner, Xiangyu Zhang Sep 2008

Automatic Failure Inducing Chain Computation Through Aligned Execution Comparison, William N. Sumner, Xiangyu Zhang

Department of Computer Science Technical Reports

No abstract provided.


A Framework For Efficient Class-Based Sampling, Mohit Saxena, Ramana Rao Kompella Sep 2008

A Framework For Efficient Class-Based Sampling, Mohit Saxena, Ramana Rao Kompella

Department of Computer Science Technical Reports

No abstract provided.


Detecting Kernel Rootkits, Ashwin Ramaswamy Sep 2008

Detecting Kernel Rootkits, Ashwin Ramaswamy

Computer Science Technical Reports

Kernel rootkits are a special category of malware that are deployed directly in the kernel and hence have unmitigated reign over the functionalities of the kernel itself. We seek to detect such rootkits that are deployed in the real world by first observing how the majority of kernel rootkits operate. To this end, comparable to how rootkits function in the real world, we write our own kernel rootkit that manipulates the network driver, thus giving us control over all packets sent into the network. We then implement a mechanism to thwart the attacks of such rootkits by noticing that a …


A Web-Based And Mobile Environmental Management System, James Carswell, Keith Gardiner, Michela Bertolotto, Andrea Rizzini, A Mandrak Sep 2008

A Web-Based And Mobile Environmental Management System, James Carswell, Keith Gardiner, Michela Bertolotto, Andrea Rizzini, A Mandrak

Articles

This paper describes a Web-based and mobile system specifically developed to monitor fish species at risk. Such a system integrates spatial functionality to allow users not only to visualise maps and metadata of the area of concern but also to perform context-aware queries and updating of spatial datasets. The spatial datasets are provided by the Canadian Department of Fisheries and Oceans (DFO) and the prototype is customised to the specific needs of the Great Lakes Laboratory for Fisheries and Aquatic Sciences (GLLFAS) Fish Habitat Section requirements for fish species at risk assessment. Currently, researchers, habitat biologists and enforcement officers have …


A Faceted Classification Based Approach To Search And Rank Web Apis, Karthik Gomadam, Ajith Harshana Ranabahu, Meenakshi Nagarajan, Amit P. Sheth, Kunal Verma Sep 2008

A Faceted Classification Based Approach To Search And Rank Web Apis, Karthik Gomadam, Ajith Harshana Ranabahu, Meenakshi Nagarajan, Amit P. Sheth, Kunal Verma

Kno.e.sis Publications

Web application hybrids, popularly known as mashups, are created by integrating services on the Web using their APIs. Support for finding an API is currently provided by generic search engines or domain specific solutions such as Google and ProgrammableWeb. Shortcomings of both these solutions in terms of and reliance on user tags make the task of identifying an API challenging. Since these APIs are described in HTML documents, it is essential to look beyond the boundaries of current approaches to Web service discovery that rely on formal descriptions. In this work, we present a faceted approach to searching and ranking …