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2008

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Articles 1261 - 1290 of 1335

Full-Text Articles in Computer Sciences

Document Selection For Extracting Entity And Relationship Instances Of Terrorist Events, Zhen Sun, Ee Peng Lim, Kuiyu Chang, Maggy Anastasia Suryanto, Rohan Kumar Gunaratna Jan 2008

Document Selection For Extracting Entity And Relationship Instances Of Terrorist Events, Zhen Sun, Ee Peng Lim, Kuiyu Chang, Maggy Anastasia Suryanto, Rohan Kumar Gunaratna

Research Collection School Of Computing and Information Systems

In this chapter, we study the problem of selecting documents so as to extract terrorist event information from a collection of documents. We represent an event by its entity and relation instances. Very often, these entity and relation instances have to be extracted from multiple documents. We therefore define an information extraction (IE) task as selecting documents and extracting from which entity and relation instances relevant to a user-specified event (aka domain specific event entity and relation extraction). We adopt domain specific IE patterns to extract potentially relevant entity and relation instances from documents, and develop a number of document …


Face Annotation Using Transductive Kernel Fisher Discriminant, Jianke Zhu, Steven C. H. Hoi, Michael R. Lyu Jan 2008

Face Annotation Using Transductive Kernel Fisher Discriminant, Jianke Zhu, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Face annotation in images and videos enjoys many potential applications in multimedia information retrieval. Face annotation usually requires many training data labeled by hand in order to build effective classifiers. This is particularly challenging when annotating faces on large-scale collections of media data, in which huge labeling efforts would be very expensive. As a result, traditional supervised face annotation methods often suffer from insufficient training data. To attack this challenge, in this paper, we propose a novel Transductive Kernel Fisher Discriminant (TKFD) scheme for face annotation, which outperforms traditional supervised annotation methods with few training data. The main idea of …


Private Query On Encrypted Data In Multi-User Setting, Feng Bao, Robert H. Deng, Xuhua Ding, Yanjiang Yang Jan 2008

Private Query On Encrypted Data In Multi-User Setting, Feng Bao, Robert H. Deng, Xuhua Ding, Yanjiang Yang

Research Collection School Of Computing and Information Systems

Searchable encryption schemes allow users to perform keyword based searches on an encrypted database. Almost all existing such schemes only consider the scenario where a single user acts as both the data owner and the querier. However, most databases in practice do not just serve one user; instead, they support search and write operations by multiple users. In this paper, we systematically study searchable encryption in a practical multi-user setting. Our results include a set of security notions for multi-user searchable encryption as well as a construction which is provably secure under the newly introduced security notions.


Analysis And Optimization Of Mobile Phone Antenna Radiation Performance In The Presence Of Head And Hand Phantoms, Erdem Ofli, Chung-Huan Li, Nicolas Chavannes, Niels Kuster Jan 2008

Analysis And Optimization Of Mobile Phone Antenna Radiation Performance In The Presence Of Head And Hand Phantoms, Erdem Ofli, Chung-Huan Li, Nicolas Chavannes, Niels Kuster

Turkish Journal of Electrical Engineering and Computer Sciences

A commercial clam shell phone CAD model is used to numerically investigate the effect of a hand phantom on mobile phone antenna radiation performance. The simulation results show that the grip of the hand phantom is the most important parameter to antenna performance. The antenna is converted into a parameterized form, then optimized to achieve the targeted multi-band performance in real-usage conditions.


Method Of Moments Solution By Using Sinc-Type Basis Functions For The Scattering From A Finite Number Of Conducting Strip Gratings, Taner Oğuzer, Fadil Kuyucuoğlu Jan 2008

Method Of Moments Solution By Using Sinc-Type Basis Functions For The Scattering From A Finite Number Of Conducting Strip Gratings, Taner Oğuzer, Fadil Kuyucuoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

A numerical method of moments (MoM) solution is applied to the electromagnetic scattering from a periodic finite conducting strip array when the incident electromagnetic plane wave E and H polarizations illuminate the grating. For such grating strip geometry, we deal with singular integral equations arising from Neumann and Dirichlet boundary conditions. MoM is applied using band-limited sinc functions as basis and testing functions. The Galerkin approach is followed in MoM formulation. The properties of the sinc function, with the infinite integral, are exploited in the computations of the main matrix elements. Also, the error in our approach goes to zero …


Zero Crossing Counter For Accuracy Improvement Of Fmcw Range Detection, Si̇nan Kurt, Şi̇mşek Demi̇r, Altunkan Hizal Jan 2008

Zero Crossing Counter For Accuracy Improvement Of Fmcw Range Detection, Si̇nan Kurt, Şi̇mşek Demi̇r, Altunkan Hizal

Turkish Journal of Electrical Engineering and Computer Sciences

For civil and military purposes FMCW radars are widely used. The theoretical background is well-established. Nevertheless, improvement of various aspects of these radars is still required. Signal processing is one of the crucial points of the system which determines the capabilities of the radar. In this study a zero crossing detector implementation, which can be efficiently used for target detection and range calculation in short range FMCW range detector is proposed. The duration between consecutive zero-crossings are used as the data instead of the number of cycles per unit time. Experimental evaluation of its performance is also given.


Comparison Of Basic Linear Filters In Extracting Auditory Evoked Potentials, Serap Aydin Jan 2008

Comparison Of Basic Linear Filters In Extracting Auditory Evoked Potentials, Serap Aydin

Turkish Journal of Electrical Engineering and Computer Sciences

In the present study, the performances of two well-known linear filtering techniques are compared for extraction of auditory Evoked Potential (EP) from a relatively small number of sweeps. Both experimental and simulated data are filtered by the two algorithms into two groups. Group A consists of Wiener filtering (WF) applications, where conventional WF and Coherence Weighted WF (CWWF)) have been assessed in combination with the Subspace Method (SM). Group B consists of the well-known adaptive filtering algorithms Least Mean Square (LMS), Recursive Least Square (RLS), and one-step Kalman filtering (KF). Both groups are tested with respect to signal-to-noise ratio (SNR) …


Biomedical Circuits And Systems Dedicated For Sensing And Neurostimulation: Case Study On Urinary Bladder Dysfunctions, Mohamad Sawan, Aguibou Ba, Faycal Mounaim, Jacques Corcos, Mostafa Elhilali Jan 2008

Biomedical Circuits And Systems Dedicated For Sensing And Neurostimulation: Case Study On Urinary Bladder Dysfunctions, Mohamad Sawan, Aguibou Ba, Faycal Mounaim, Jacques Corcos, Mostafa Elhilali

Turkish Journal of Electrical Engineering and Computer Sciences

This paper covers circuits and systems techniques for the construction of high reliability biosensing and neurostimulation smart medical devices. Such microsystems are dedicated for interconnections through the peripheral neural systems. Case study related to applications such as bladder control is discussed. Available electrical neurostimulation techniques for the rehabilitation of urinary bladder functions do not allow an adequate voiding due to dyssynergia between the bladder and the sphincter. A new implantable stimulator, built with commercially available electronic components, was designed to overcome these difficulties. The proposed system performs two types of stimulations: Selective Stimulation for bladder voiding and Permanent Stimulation to …


Role Of Artificial Intelligence In The Reliability Evaluation Of Electric Power Systems, Chanan Singh, Lingfeng Wang Jan 2008

Role Of Artificial Intelligence In The Reliability Evaluation Of Electric Power Systems, Chanan Singh, Lingfeng Wang

Turkish Journal of Electrical Engineering and Computer Sciences

Every reliability analysis effort, in some way, involves searching the state space of the system for those states that represent the events of interest, typically failure of the system or a given node to meet the demand. This essentially translates into a search procedure to efficiently identify states to be examined and then using a mechanism to evaluate these states. Traditionally, reliability analysis methods are based either on an implicit or explicit enumeration process or Monte Carlo sampling. More recently, methods based on artificial intelligence have been investigated both as an alternative to Monte Carlo for the search process as …


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.


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 …


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 …


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 …


Evolutionary Algorithms For The Unit Commitment Problem, A. Şi̇ma Uyar, Belgi̇n Türkay Jan 2008

Evolutionary Algorithms For The Unit Commitment Problem, A. Şi̇ma Uyar, Belgi̇n Türkay

Turkish Journal of Electrical Engineering and Computer Sciences

This paper compares three evolutionary computation techniques, namely Steady-State Genetic Algorithms, Evolutionary Strategies and Differential Evolution for the Unit Commitment Problem. The comparison is based on a set of experiments conducted on benchmark datasets as well as on real-world data obtained from the Turkish Interconnected Power System. The results of two state-of-the-art evolutionary approaches, namely a Generational Genetic Algorithm and a Memetic Algorithm for the same benchmark datasets are also included in the paper for comparison. The tests show that Differential Evolution is the best performer among all approaches on the test data used in the paper. The performances of …


Modeling And Design Of Low Cost Customizable Household Robot, Bharat Narahari Jan 2008

Modeling And Design Of Low Cost Customizable Household Robot, Bharat Narahari

LSU Master's Theses

Just as the growth of Personal computer, Mobile phones and Automobiles took place in last 3 decades, the personal robotics industry still in its nascent stage, is heading in the same direction. This thesis explores the concept of customizable household robots (CHR) in the robotics community. An attempt has been made to design a customizable robot by extending the 2 wheel differential drive kinematic model to 4 wheel independent differential drive kinematic model. A framework for CHR is developed which will be able to do various household repetitive tasks. Just as we can assemble a PC by buying its individual …


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.


Model-Driven Search-Based Loop Fusion Optimization For Handwritten Code, Pamela Bhattacharya Jan 2008

Model-Driven Search-Based Loop Fusion Optimization For Handwritten Code, Pamela Bhattacharya

LSU Master's Theses

The Tensor Contraction Engine (TCE) is a compiler that translates high-level, mathematical tensor contraction expressions into efficient, parallel Fortran code. A pair of optimizations in the TCE, the fusion and tiling optimizations, have proven successful for minimizing disk-to-memory traffic for dense tensor computations. While other optimizations are specific to tensor contraction expressions, these two model-driven search-based optimization algorithms could also be useful for optimizing handwritten dense array computations to minimize disk to memory traffic. In this thesis, we show how to apply the loop fusion algorithm to handwritten code in a procedural language. While in the TCE the loop fusion …


Failure-Awareness And Dynamic Adaptation In Data Scheduling, Mehmet Balman Jan 2008

Failure-Awareness And Dynamic Adaptation In Data Scheduling, Mehmet Balman

LSU Master's Theses

Over the years, scientific applications have become more complex and more data intensive. Especially large scale simulations and scientific experiments in areas such as physics, biology, astronomy and earth sciences demand highly distributed resources to satisfy excessive computational requirements. Increasing data requirements and the distributed nature of the resources made I/O the major bottleneck for end-to-end application performance. Existing systems fail to address issues such as reliability, scalability, and efficiency in dealing with wide area data access, retrieval and processing. In this study, we explore data-intensive distributed computing and study challenges in data placement in distributed environments. After analyzing different …


A Growth-Theoretic Empirical Analysis Of Simultaneity In Cross-National E-Commerce Development, Shu-Chun Ho, Robert J. Kauffman, Ting-Peng Liang Jan 2008

A Growth-Theoretic Empirical Analysis Of Simultaneity In Cross-National E-Commerce Development, Shu-Chun Ho, Robert J. Kauffman, Ting-Peng Liang

Research Collection School Of Computing and Information Systems

The emergence of information and communication technologies infrastructure has transformed the global economy. The development of information technology infrastructure is limited to some developed countries though. This research explores the role of information technology infrastructure in B2C e-commerce growth at the country-level from the perspective of growth theory in economics. We propose a hybrid exogenous and endogenous growth model to explain e-commerce growth. We estimate a panel data model that incorporates the direct effects of e-commerce infrastructure and other key explanatory variables. We further specify a simultaneous effects model that permits the analysis of reverse causality in the association between …


My Collaboration With Raj Mittra: Contributions To The Theory Of Perfectly Matched Layers, Mustafa Kuzuoğlu Jan 2008

My Collaboration With Raj Mittra: Contributions To The Theory Of Perfectly Matched Layers, Mustafa Kuzuoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


From Engineering Electromagnetics To Electromagnetic Engineering: Using Computational Electromagnetics For Synthesis Problems, Anton G. Tijhuis, Martijn C. Van Beurden, Bastiaan P. De Hon, Hubregt J. Visser Jan 2008

From Engineering Electromagnetics To Electromagnetic Engineering: Using Computational Electromagnetics For Synthesis Problems, Anton G. Tijhuis, Martijn C. Van Beurden, Bastiaan P. De Hon, Hubregt J. Visser

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a two-stage approach is proposed for using computational electromagnetics in antenna engineering. First, stochastic optimization techniques are used in combination with approximate models. Second, line-search techniques are combined with full-wave modeling. For the first stage, we show an illustrative example. The second stage is considered in detail; both the acceleration of the underlying field computations and the implementation of the optimization are discussed.


A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski Jan 2008

A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski

Turkish Journal of Electrical Engineering and Computer Sciences

This paper summarizes our recent research efforts to realize efficient electrically small antenna (EESA) systems based on ideal analytical and numerical metamaterial-based antenna systems, and physically realized metamaterial-inspired antenna designs. Our theoretical and numerical studies of the radiation and resonance behaviors of the proposed metamaterial-based EESA systems, as well as our efforts to conceptualize structures which might be used to build them, have led to the discovery of several realizable metamaterial-inspired EESA systems. The measurement results confirm the numerical performance predictions.


Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇ Jan 2008

Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇

Turkish Journal of Electrical Engineering and Computer Sciences

A dual-band microstrip antenna based on split-ring elements is introduced for WLAN (2.4/5.2 GHz) applications. The proposed split-ring antenna (SRA) has a compact novel design which provides about 2% impedance-bandwidth without a need for additional matching network. Analysis and design of the proposed microstrip antenna is carried out by means of full-wave simulators based on the finite-element method.


Web Search Algorithms And Pagerank, Laleh Samarbakhsh Jan 2008

Web Search Algorithms And Pagerank, Laleh Samarbakhsh

Theses and Dissertations (Comprehensive)

The mathematical theory underlying the Google search engine is the PageRank algorithm, first introduced by Sergey Brin and Lawrence Page, the founders of Google. A ranking of web pages is made considering many criteria. PageRank exploits the graph structure of the web. The web’s hyperlink structure forms a massive directed graph, where the web pages are presented as nodes and hyperlinks as edges. The PageRank equation finds a score by solving a recursive equation which calculates the PageRank vector. The PageRank vector is the stationary distribution of an ergodic Markov chain. The Perron-Frobenius theorem ensures that the primitive matrix produced …


Object Detection And Classification With Applications To Skin Cancer Screening, Jonathan Blackledge, Dmitryi Dubovitskiy Jan 2008

Object Detection And Classification With Applications To Skin Cancer Screening, Jonathan Blackledge, Dmitryi Dubovitskiy

Articles

This paper discusses a new approach to the processes of object detection, recognition and classification in a digital image. The classification method is based on the application of a set of features which include fractal parameters such as the Lacunarity and Fractal Dimension. Thus, the approach used, incorporates the characterisation of an object in terms of its texture.

The principal issues associated with object recognition are presented which includes two novel fast segmentation algorithms for which C++ code is provided. The self-learning procedure for designing a decision making engine using fuzzy logic and membership function theory is also presented and …


Covert Encryption And Document Authentication Using Texture Coding, Jonathan Blackledge, Mary Hallot Jan 2008

Covert Encryption And Document Authentication Using Texture Coding, Jonathan Blackledge, Mary Hallot

Articles

With the improvements in the quality of Commercial-Off-The-Shelf (COTS) printing and scanning devices, the ability to counterfeit documents has become a widespread problem. Consequently, there has been an increasing demand to develop digital watermarking techniques which can be applied to both electronic and printed images (and documents) that can be authenticated, prevent unauthorized copying and withstand abuse and degradation. In this paper , a new approach to digital watermarking is presented and a range of possible applications are considered. The process is defined by using concepts and techniques borrowed from Cryptography. It is based on computing a 'scramble image' by …


Book Review: Challenges To Digital Forensic Evidence, Gary C. Kessler Jan 2008

Book Review: Challenges To Digital Forensic Evidence, Gary C. Kessler

Publications

This document is Dr. Kessler's review of Challenges to Digital Forensic Evidence, by Fred Cohen. Fred Cohen & Associates, 2008. ISBN 1-878109-41-3


Anti-Phishing Models: Main Challenges, Edina Hatunic-Webster Jan 2008

Anti-Phishing Models: Main Challenges, Edina Hatunic-Webster

Conference papers

Phishing is a form of online identity theft in which the attacker attempts to fraudulently retrieve a legitimate user's account information, logon credentials or identity information in general. The compromised information is then used for withdrawing money online, taking out cash advances, or making purchases of goods and services on the accounts. Various solutions have been proposed and developed in response to phishing. As phishing is a business problem, the solutions target both non-technical and technical areas. This paper investigates the current anti-phishing solutions and critically reviews their usage, security weaknesses and their effectiveness. The analysis of these models points …


Tunable True-Time Delay Unit Based On Opto-Vlsi Processing, Feng Xiao, Budi Juswardy, Kamal Alameh Jan 2008

Tunable True-Time Delay Unit Based On Opto-Vlsi Processing, Feng Xiao, Budi Juswardy, Kamal Alameh

Research outputs pre 2011

A novel tunable true-time delay unit is proposed and demonstrated. The unit is based on the use of an Opto-VLSI processor that dynamically selects a single waveband or multiple wavebands from an RF-modulated broadband optical signal and routes them to a high-dispersion fiber for arbitrary time delay synthesis. Experimental results demonstrate continuously tunable time delay of up to 4 ns.


Obstacle Detection And Spectral Discrimination Using Multi-Wavelength Motionless Wide Angle Laser Scanning, Kaveh Sahba, Kamal Alameh, Clifton Smith Jan 2008

Obstacle Detection And Spectral Discrimination Using Multi-Wavelength Motionless Wide Angle Laser Scanning, Kaveh Sahba, Kamal Alameh, Clifton Smith

Research outputs pre 2011

Static laser scanning over a wide angle is demonstrated by ranging to 20 laser beams generated by a novel cylindrical quasi-cavity waveguide, using laser triangulation. Baseline distances and outgoing angles unique to each laser beam are calculated by modelling the triangulation arrangement using a system of linear equations and plotting principal rays. The quasi-cavity waveguide, imaging lens and focal plane are also plotted. The system is calibrated by finding optimal values for uncertain instrumental parameters using constrained non-linear optimization. Distances calculated over 5m indoors result in accuracies above 93%. Discrete laser spectroscopy using 640nm and 785nm laser diodes is also …