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Articles 10831 - 10860 of 12808

Full-Text Articles in Physical Sciences and Mathematics

A New Approach Using Temporal Radial Basis Function In Chronological Series, Mustapha Guezouri Jan 2008

A New Approach Using Temporal Radial Basis Function In Chronological Series, Mustapha Guezouri

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present an extended form of Radial Basis Function network called Temporal-RBF (T-RBF) network. This extended network can be used in decision rules and classification in Spatio-Temporal domain applications, like speech recognition, economic fluctuations, seismic measurements and robotics applications. We found that such a network complies with relative ease to constraints such as capacity of universal approximation, sensibility of node, local generalisation in receptive field, etc. For an optimal solution based on a probabilistic approach with a minimum of complexity, we propose two TRBF models (1 and 2). Application to the problem of Mackey-Glass time series has …

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Dispersion Analysis Of The Adi-Fdtd And S-Fdtd Methods, Mehmet Kuşaf, Abdullah Y. Öztoprak Jan 2008

Dispersion Analysis Of The Adi-Fdtd And S-Fdtd Methods, Mehmet Kuşaf, Abdullah Y. Öztoprak

Turkish Journal of Electrical Engineering and Computer Sciences

Numerical dispersion performances of ADI-FDTD and S-FDTD methods have been compared. It has been shown that for time steps below the stability limits of the S-FDTD method it has much better dispersion performance compared with the ADI-FDTD method and that the S-FDTD method can be usefully employed for space increments in the order of \lambda/25 to \lambda/50.

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Pattern Synthesis With Uniform Circular Arrays For The Reduction Of Wcdma Intercell Interference, Mohammed Al-Husseini, Elias Yaacoub, Karim Y. Kabalan, Ali El-Hajj Jan 2008

Pattern Synthesis With Uniform Circular Arrays For The Reduction Of Wcdma Intercell Interference, Mohammed Al-Husseini, Elias Yaacoub, Karim Y. Kabalan, Ali El-Hajj

Turkish Journal of Electrical Engineering and Computer Sciences

The deployment of advanced antenna arrays at the base stations of cellular systems is a key technique in reducing intercell interference, and thus increasing the number of served users. Uniform circular arrays (UCAs) provide 360 degrees of coverage, their patterns are steering-invariant and their sidelobe levels are controllable. This paper investigates the use of UCAs having specially synthesized patterns at the base stations of WCDMA cellular systems. The decrease in the ratio of intercell interference to intracell power resulting from the use of these arrays in a beam-steering scheme will be assessed, and the advantages and disadvantages of each pattern …

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Distance Relaying Algorithm For Double-Circuit Transmission Line With Compensation For Reactance Effect Under Standard Availability Of Measurements, Jan Izykowski, Marcin Bozek Jan 2008

Distance Relaying Algorithm For Double-Circuit Transmission Line With Compensation For Reactance Effect Under Standard Availability Of Measurements, Jan Izykowski, Marcin Bozek

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with non-pilot distance protection of a double-circuit transmission line. Negative impact of the reactance effect, appearing in measuring a fault loop impedance, on operation of the relay is discussed. An adaptive algorithm allowing one to prevent the relay from mis- or mal-operation caused by the reactance effect is introduced. The algorithm is designed for a standard availability of measurements from one end of the double-circuit line, i.e. when three-phase voltage and current from the faulted line circuit, and additionally zero-sequence current from the healthy line circuit, are provided as the relay input signals. The algorithm is based …

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Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek Jan 2008

Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper time-frequency methods have been investigated for complex investigations of transient states in wind power plants. Application of parallel processing in time and frequency domain brought new findings in description of wind power plants working under transient conditions. Proposed algorithms represents standard Short-Time Fourier Transform (STFT) as well as alternative methods associated with Cohen's class: Choi-Williams Distribution (CWD) and Zhao-Atlas-Marks Distribution (ZAMD). In order to explore advantages and disadvantages of the method several experiments were performed using model of squirrel-cage induction machine connected directly to the grid. Investigated phenomena concerned power distortion caused by switching-on capacitor banks and …

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Columbia University/Vireo-Cityu/Irit Trecvid2008 High-Level Feature Extraction And Interactive Video Search, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky Jan 2008

Columbia University/Vireo-Cityu/Irit Trecvid2008 High-Level Feature Extraction And Interactive Video Search, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky

Research Collection School Of Computing and Information Systems

In this report, we present overview and comparative analysis of our HLF detection system, which achieves the top performance among all type-A submissions in 2008. We also describe preliminary evaluation of our video search system, CuZero, in the interactive search task.

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Modeling Timed Component-Based Real-Time Systems, Huang-Ming Huang, Christopher Gill Jan 2008

Modeling Timed Component-Based Real-Time Systems, Huang-Ming Huang, Christopher Gill

All Computer Science and Engineering Research

Component based middleware helps to facilitate software reuse by separating application-specific concerns into modular components that are shielded from the concerns of other components and from the common concerns addressed by underlying middleware services. In real-time systems, concerns such as invocation rates, execution latencies, deadlines, and concurrency semantics cross-cut multiple component and middleware abstractions. Thus, the verification of these systems must consider features of the application components (e.g., their execution latencies and relative invocation rates) and of the supporting middleware (e.g., concurrency and scheduling) together. However, existing approaches only address a sub-set of the features that must be modeled in …

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Verification Of Component-Based Distributed Real-Time Systems, Huang-Ming Huang, Christopher Gill Jan 2008

Verification Of Component-Based Distributed Real-Time Systems, Huang-Ming Huang, Christopher Gill

All Computer Science and Engineering Research

Component-based software architectures enable reuse by separating application-specific concerns into modular components that are shielded from each other and from common concerns addressed by underlying services. Even so, concerns such as invocation rates, execution latencies, deadlines, and concurrency and scheduling semantics still cross-cut component boundaries in many real-time systems. Verification of these systems therefore must consider how composition of components relates to timing, resource utilization, and other properties. However, existing approaches only address a sub-set of the concerns that must be modeled in component-based distributed real-time systems, and a new more comprehensive approach is thus needed. To address that need, …

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Practical Schedulability Analysis For Generalized Sporadic Tasks In Distributed Real-Time Systems, Yuanfang Zhang, Donald K. Krecker, Christopher Gill, Chenyang Lu, Guatam H. Thaker Jan 2008

Practical Schedulability Analysis For Generalized Sporadic Tasks In Distributed Real-Time Systems, Yuanfang Zhang, Donald K. Krecker, Christopher Gill, Chenyang Lu, Guatam H. Thaker

All Computer Science and Engineering Research

Existing off-line schedulability analysis for real-time systems can only handle periodic or sporadic tasks with known minimum inter-arrival times. Modeling sporadic tasks with fixed minimum inter-arrival times is a poor approximation for systems in which tasks arrive in bursts, but have longer intervals between the bursts. In such cases, schedulability analysis based on the existing sporadic task model is pessimistic and seriously overestimates the task's time demand. In this paper, we propose a generalized sporadic task model that characterizes arrival times more precisely than the traditional sporadic task model, and we develop a corresponding schedulability analysis that computes tighter bounds …

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Scheduling For Reliable Execution In Autonomic Systems, Terry Tidwell, Robert Glaubius, Christopher Gill, William D. Smart Jan 2008

Scheduling For Reliable Execution In Autonomic Systems, Terry Tidwell, Robert Glaubius, Christopher Gill, William D. Smart

All Computer Science and Engineering Research

Scheduling the execution of multiple concurrent tasks on shared resources such as CPUs and network links is essential to ensuring the reliable operation of many autonomic systems. Well known techniques such as rate-monotonic scheduling can offer rigorous timing and preemption guarantees, but only under assumptions (i.e., a fixed set of tasks with well-known execution times and invocation rates) that do not hold in many autonomic systems. New hierarchical scheduling techniques are better suited to enforce the more flexible execution constraints and enforcement mechanisms that are required for autonomic systems, but a rigorous foundation for verifying and enforcing concurrency and timing …

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Financial Monte Carlo Simulation On Architecturally Diverse Systems, Naveen Singla, Michael Hall, Berkley Shands, Roger D. Chamberlain Jan 2008

Financial Monte Carlo Simulation On Architecturally Diverse Systems, Naveen Singla, Michael Hall, Berkley Shands, Roger D. Chamberlain

All Computer Science and Engineering Research

Computational finance relies heavily on the use of Monte Carlo simulation techniques. However, Monte Carlo simulation is computationally very demanding. We demonstrate the use of architecturally diverse systems to accelerate the performance of these simulations, exploiting both graphics processing units and field-programmable gate arrays. Performance results include a speedup of 74× relative to an 8 core multiprocessor system (180× relative to a single processor core).

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Reliable Data Collection From Mobile Users For Real-Time Clinical Monitoring, Octav Chipara, Christopher Brooks, Sangeeta Bhattacharya, Chenyang Lu Jan 2008

Reliable Data Collection From Mobile Users For Real-Time Clinical Monitoring, Octav Chipara, Christopher Brooks, Sangeeta Bhattacharya, Chenyang Lu

All Computer Science and Engineering Research

Real-time patient monitoring is critical to early detection of clinical patient deterioration in general hospital wards. A key challenge in such applications is to reliably deliver sensor data from mobile patients. We present an empirical analysis on the reliability of data collection from wireless pulse oximeters attached to users. We observe that most packet loss occur from mobile users to their first-hop relays. Based on this insight we developed the Dynamic Relay Association Protocol (DRAP), a simple and effective mechanism for dynamically discovering the right relays for wireless sensors attached to mobile users. DRAP enables highly reliable data collection from …

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Partial Program Admission By Path Enumeration, Michael Wilson, Ron Cytron, Jon Turner Jan 2008

Partial Program Admission By Path Enumeration, Michael Wilson, Ron Cytron, Jon Turner

All Computer Science and Engineering Research

Real-time systems on non-preemptive platforms require a means of bounding the execution time of programs for admission purposes. Worst-Case Execution Time (WCET) is most commonly used to bound program execution time. While bounding a program's WCET statically is possible, computing its true WCET is difficult without significant semantic knowledge. We present an algorithm for partial program admission, suited for non-preemptive platforms, using dynamic programming to perform explicit enumeration of program paths. Paths - possible or not - are bounded by the available execution time and admitted on a path-by-path basis without requiring semantic knowledge of the program beyond its Control …

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Transcriptome Analysis Of Alzheimer's Disease Identifies Links To Cardiovascular Disease, Monika Ray, Jianhua Ruan, Weixiong Zhang Jan 2008

Transcriptome Analysis Of Alzheimer's Disease Identifies Links To Cardiovascular Disease, Monika Ray, Jianhua Ruan, Weixiong Zhang

All Computer Science and Engineering Research

No abstract provided.

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Deciding Joinability Modulo Ground Equations In Operational Type Theory, Adam Petcher, Aaron Stump Jan 2008

Deciding Joinability Modulo Ground Equations In Operational Type Theory, Adam Petcher, Aaron Stump

All Computer Science and Engineering Research

Operational Type Theory (OpTT) can be used to construct and check proofs related to programs, but the development of these proofs can be somewhat tedious. An algorithm is presented that can be used to automatically generate proofs of equality in OpTT. The algorithm takes as input a set of ground equations and two terms that should be tested for joinability modulo the supplied ground equations. The algorithm will equate the terms if and only if there exists an OpTT proof that can equate the two terms using only the proof rules related to evaluation under the operational semantics, symmetry, transitivity, …

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Concept Detection: Convergence To Local Features And Opportunities Beyond, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky Jan 2008

Concept Detection: Convergence To Local Features And Opportunities Beyond, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky

Research Collection School Of Computing and Information Systems

No abstract provided.

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Byzantium Beneath The Black Sea, Bridget Buxton, Robert Ballard, Michael Brennan, Dwight Coleman, Katy Croff, Christopher Roman, Dan Davis, Dennis Piechota, Sergiy Voronov Dec 2007

Byzantium Beneath The Black Sea, Bridget Buxton, Robert Ballard, Michael Brennan, Dwight Coleman, Katy Croff, Christopher Roman, Dan Davis, Dennis Piechota, Sergiy Voronov

Christopher N. Roman

This poster reports on the August 2007 Black Sea Expedition of the Institute for Archaeological Oceanography at the University of Rhode Island (IAO) and the Institute for Exploration (IFE), in collaboration with the Department of the Underwater Heritage of Ukraine. This year’s work marks a new phase in a multi-year (2000–2012) archaeological and oceanographic survey of the Black Sea. 2007 fieldwork focuses on two Byzantine shipwrecks. The 10th century C.E. shipwreck Chersonesos A (discovered in 2006) lies at 140 m depth in the suboxic zone off the Crimean peninsula. The ship carried a cargo of one-handled jars of a widely …

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Diagnosing Faults In Electrical Power Systems Of Spacecraft And Aircraft, Ole J. Mengshoel, Adnan Darwichse, Keith Cascio, Mark Chavira, Scott Poll, Serdar Uckun Dec 2007

Diagnosing Faults In Electrical Power Systems Of Spacecraft And Aircraft, Ole J. Mengshoel, Adnan Darwichse, Keith Cascio, Mark Chavira, Scott Poll, Serdar Uckun

Ole J Mengshoel

Electrical power systems play a critical role in spacecraft and aircraft. This paper discusses our development of a diagnostic capability for an electrical power system testbed, ADAPT, using probalistic techniques. In the context of ADAPT, we present two challenges, regarding modelling and real-time performance, often encountered in real-world diagnostic applications. To meet the modelling challenge, we discuss our novel high-level specification language which supports auto-generation of Bayesian networks. To meet the real-time challenge, we compile Bayesian networks intro arithmetic circuits. Arithmetic circuits typically have small footprints and are optimized for the real-time avionics systems found in spacecraft and aircraft. Using …

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Evaluation Of Robocode As A Teaching Tool For Computer Programming, Arnold Hensman Dec 2007

Evaluation Of Robocode As A Teaching Tool For Computer Programming, Arnold Hensman

Conference Papers

Robocode began as an educational tool to aid in learning Java programming. It has since evolved into something of a phenomenon, as the prospect of creating simple to complex virtual tanks appears to pose an attractive challenge to both novice and expert programmers alike. What started out as a teaching tool has grown into a worldwide network of competitors, all keen to prove that their ‘bot’ stands out from the crowd. Competitions are well organised and many Robocode events are a PR dream for the computing companies that sponsor them. Without a doubt, this easy to use application has sparked …

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What Is Rcu, Fundamentally?, Paul E. Mckenney, Jonathan Walpole Dec 2007

What Is Rcu, Fundamentally?, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Read-copy update (RCU) is a synchronization mechanism that was added to the Linux kernel in October of 2002. RCU achieves scalability improvements by allowing reads to occur concurrently with updates. In contrast with conventional locking primitives that ensure mutual exclusion among concurrent threads regardless of whether they be readers or updaters, or with reader-writer locks that allow concurrent reads but not in the presence of updates, RCU supports concurrency between a single updater and multiple readers. RCU ensures that reads are coherent by maintaining multiple versions of objects and ensuring that they are not freed up until all pre-existing read-side …

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Self-Organizing Neural Architectures And Cooperative Learning In A Multiagent Environment, Dan Xiao, Ah-Hwee Tan Dec 2007

Self-Organizing Neural Architectures And Cooperative Learning In A Multiagent Environment, Dan Xiao, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Temporal-Difference–Fusion Architecture for Learning, Cognition, and Navigation (TD-FALCON) is a generalization of adaptive resonance theory (a class of self-organizing neural networks) that incorporates TD methods for real-time reinforcement learning. In this paper, we investigate how a team of TD-FALCON networks may cooperate to learn and function in a dynamic multiagent environment based on minefield navigation and a predator/prey pursuit tasks. Experiments on the navigation task demonstrate that TD-FALCON agent teams are able to adapt and function well in a multiagent environment without an explicit mechanism of collaboration. In comparison, traditional Q-learning agents using gradient-descent-based feedforward neural networks, trained with the …

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"Conversational" Dialogues In Direct-Manipulation Interfaces, David G. Novick Oct 2007

"Conversational" Dialogues In Direct-Manipulation Interfaces, David G. Novick

David G. Novick

This paper reports ongoing research in extending direct-manipulation interfaces by incorporating, via the direct-manipulation modality itself, interaction techniques that add kinds of language features associated with spoken conversation. The paper proposes means of implementing ways for a user of a direct-manipulation system to define new kinds of relations among objects in the interface.

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Users And Uses Of Synchronous Business Communications Software, David G. Novick, Eleanor Wynn Oct 2007

Users And Uses Of Synchronous Business Communications Software, David G. Novick, Eleanor Wynn

David G. Novick

To help designers and authors understand users' intentions and work practices for synchronous business communications in a systematic way, we used ethnographic and task-analytic techniques to collect, analyze and classify evidence of the activities of potential users as they conducted their work lives. The interactions we observed among our users took place through a variety of modalities. We found eight categories of tasks for the collaborative or interactive work in which our subjects engaged. Based on these data, we were able to classify roles of potential users of synchronous business communications software into a set of "archetypes" that characterize their …

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Hands-Free Documentation, Karen Ward, David G. Novick Oct 2007

Hands-Free Documentation, Karen Ward, David G. Novick

David G. Novick

In this paper, we introduce an analysis of the requirements and design choices for hands-free documentation. Hands-busy tasks such as cooking or car repair may require substantial interruption of the task: moving the pan off the burner and wiping hands, or crawling out from underneath the car. We review the need for hands-free documentation and explore the role of task in the use of documentation. Our central analysis examines the roles and characteristics of input and output modalities of hands-free documentation. In particular, we review the use of speech as an input modality, and then visual means and speech as …

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An Interaction Initiative Model For Documentation, David G. Novick, Karen Ward Oct 2007

An Interaction Initiative Model For Documentation, David G. Novick, Karen Ward

David G. Novick

In this paper we propose a model of creation and use of documentation based on the concept of mixed-initiative interaction. In our model, successful single-initiative interaction is characterized by grounding of contributions, and successful mixed-initiative interaction is characterized by both grounding and agreement. Just as in spoken conversation, achievement of actual agreement depends on the intentions of both parties; agreement is achieved when the reader follows the documentation’s instructions. In fact, readers are not obligated to—and often do not—act according to the author’s intentions. By making these dynamics explicit, the model can aid authors in developing effective documentation. The paper …

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Assessing Effectiveness Of Personality Style In Documentation, Kenneth Sayles, David G. Novick Oct 2007

Assessing Effectiveness Of Personality Style In Documentation, Kenneth Sayles, David G. Novick

David G. Novick

This paper extends previous work by other researchers that indicated that users of computers preferred a computer with a personality that was similar to theirs. We conducted a similar experiment, but looking beyond preference to see if the personality of documentation would make a difference in the user’s performance. Our data suggest did not indicate that personality match affects performance; and if such a relationship exists it is likely to be weak. We discuss the related research, describe our methodology, present our results, and describe their implications and limitations.

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A Two-Phase Approach To Interactivity Enhancement For Large-Scale Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou Oct 2007

A Two-Phase Approach To Interactivity Enhancement For Large-Scale Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou

Research Collection School Of Computing and Information Systems

Distributed virtual environments (DVEs) are distributed systems that allow multiple geographically distributed clients (users) to interact simultaneously in a computer-generated, shared virtual world. Applications of DVEs can be seen in many areas nowadays, such as online games, military simulations, collaborative designs, etc. To support large-scale DVEs with real-time interactions among thousands or even more distributed clients, a geographically distributed server architecture (GDSA) is generally needed, and the virtual world can be partitioned into many distinct zones to distribute the load among the servers. Due to the geographic distributions of clients and servers in such architectures, it is essential to efficiently …

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Ceg 420/620: Computer Architecture, Jack Jean Oct 2007

Ceg 420/620: Computer Architecture, Jack Jean

Computer Science & Engineering Syllabi

No abstract provided.

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Ceg 210: Pc Networking I, Karen Meyer Oct 2007

Ceg 210: Pc Networking I, Karen Meyer

Computer Science & Engineering Syllabi

Introduction to PC networking hardware, concepts, and technologies. Focus is on LAN administration, hardware and software configuration.

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Ceg 220: Introduction To C Programming For Engineers I, Robert Helt Oct 2007

Ceg 220: Introduction To C Programming For Engineers I, Robert Helt

Computer Science & Engineering Syllabi

This course provides a general introduction to computers as a problem-solving tool using the C programming language. Emphasis is on algorithms and techniques useful to engineers. Topics include data representation, debugging, and program verification. 4 credit hours. Prerequisite: MTH 229 (Calculus I) or EGR 101 (Engineering Mathematics).f

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