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Computer Sciences

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2009

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Articles 241 - 264 of 264

Full-Text Articles in Computer Engineering

Accurate Prediction Of Crosstalk For Rc Interconnects, Selahatti̇n Sayil, Merlyn Rudrapati Jan 2009

Accurate Prediction Of Crosstalk For Rc Interconnects, Selahatti̇n Sayil, Merlyn Rudrapati

Turkish Journal of Electrical Engineering and Computer Sciences

This work proposes an accurate crosstalk noise estimation method in the presence of multiple RC lines for use in design automation tools. The method correctly models the loading effects of non switching aggressors and aggressor tree branches using resistive shielding effect and realistic exponential input waveform. Noise peak and width expressions derived show very good results in comparison to HSPICE results. Results show that average error for noise peak is 4.1% and for the width is 6.8% while allowing for very fast analysis.


Analytical Regularization Method For Electromagnetic Wave Diffraction By Axially Symmetrical Thin Annular Strips, Fati̇h Di̇kmen, Yury Alexanderovich Tuchkin Jan 2009

Analytical Regularization Method For Electromagnetic Wave Diffraction By Axially Symmetrical Thin Annular Strips, Fati̇h Di̇kmen, Yury Alexanderovich Tuchkin

Turkish Journal of Electrical Engineering and Computer Sciences

A new mathematically rigorous and numerically efficient method based on the combination of Orthogonal Polynomials Method, and Analytical Regularization Method, for electromagnetic wave diffraction by a model structure for various antennae such as Fresnel zone plates is proposed. It can be used as validation tool for the other (more general or less accurate) numerical methods and physical approaches. The initial boundary value problem is equivalently reduced to the infinite system of the linear algebraic equations of the second kind, i.e. to an equation of the type (I+H) x=b in the space l_2 with compact operator H. This equation can be …


Cdm Based Controller Design For Nonlinear Heat Exchanger Process, Erkan İmal Jan 2009

Cdm Based Controller Design For Nonlinear Heat Exchanger Process, Erkan İmal

Turkish Journal of Electrical Engineering and Computer Sciences

Most processes are nonlinear, and their control is a difficult yet important problem. The heat exchanger is an example onesuch nonlinear process. In the present paper, the effect of process nonlinearity on the performance of set point tracking and disturbance rejection in two controller methods is investigated. Initially, afirst order plus dead time (FOPDT) model of the process is obtainedvia a software known as Loop-Pro Trainer. Then, the PI-controller tuning values are computed using the internal model control (IMC) correlations based on truncated (first-order) Taylor series approximation. Next, another controller is designed using the coefficient diagram method (CDM). Finally, the …


Polymorphic Worm Detection Using Strong Token-Pair Signatures, Burak Bayoğlu, İbrahi̇m Soğukpinar Jan 2009

Polymorphic Worm Detection Using Strong Token-Pair Signatures, Burak Bayoğlu, İbrahi̇m Soğukpinar

Turkish Journal of Electrical Engineering and Computer Sciences

Malicious software has become a big threat to information systems, which are widely used to store, transfer and process information for many critical assets. Worms are one of the most harmful network-enabled malicious software that can threaten networks and applications. Two main characteristics of worms distinguish them from the well-known virus programs and as a result are much more dangerous than the virus programs. First, they do not need to attach themselves to an existing program. Second, worms do not require end-user interaction to realize the intended attack. Therefore, a large number of victims can be infected in a short …


Emc Education At The University Of Technology Zurich, Gökhan Apaydin, Ni̇yazi̇ Ari Jan 2009

Emc Education At The University Of Technology Zurich, Gökhan Apaydin, Ni̇yazi̇ Ari

Turkish Journal of Electrical Engineering and Computer Sciences

This paper illustrates educational issues in electromagnetic compatibility (EMC) engineering in Switzerland and presents the contents of courses and practical materials for EMC education at the University of Technology Zurich. After giving the fundamentals of theoretical part, practical applications have been given to make students and engineers aware of EMC issues and its problems.


Electromagnetic Compatibility Engineering Education: Problems, Challenges And Perspectives, Levent Sevgi̇ Jan 2009

Electromagnetic Compatibility Engineering Education: Problems, Challenges And Perspectives, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Education and training problems and challenges in EMC Engineering are discussed. The necessity of physics-based modeling (theory) and hands-on training (practice) are emphasized. An introductory level EMC lecture and a short course outline are given for modern EMC education.


Two Dimensional Ebg Structures For Multiband Noise Mitigation, Antonio Orlandi, Antonio Ciccomancini Jan 2009

Two Dimensional Ebg Structures For Multiband Noise Mitigation, Antonio Orlandi, Antonio Ciccomancini

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a two dimensional (2D) electromagnetic Bandgap (EBG) structure is proposed for multi band noise mitigation in PWR/GND plane pairs. Excellent noise suppression (-60 dB) is achieved in multiple bands within the range 0--8 GHz with a low start frequency. Because of the 2D EBG, no additional metal layer is required. Signal Integrity analysis is also studied by modelling a microstrip to stripline transition (both single ended and differential) and by evaluating insertion loss, TDR as well as eye diagram.


Electromagnetic Radiation From Multilayer Printed Circuit Boards: A 3d Fdtd-Based Virtual Emission Predictor, Gonca Çakir, Mustafa Çakir, Levent Sevgi̇ Jan 2009

Electromagnetic Radiation From Multilayer Printed Circuit Boards: A 3d Fdtd-Based Virtual Emission Predictor, Gonca Çakir, Mustafa Çakir, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

A novel FDTD-based virtual electromagnetic compatibility tool for the prediction of electromagnetic emissions from a multilayer printed circuit board is introduced. Tests are performed with characteristic structures and sample simulation results are presented.


Vlsi-Cell Placement Technique For Architecture Of Field Programmable Gate Array (Fpga) Design, Avnesh Verma, Sunil Dhingra, M. K. Soni Jan 2009

Vlsi-Cell Placement Technique For Architecture Of Field Programmable Gate Array (Fpga) Design, Avnesh Verma, Sunil Dhingra, M. K. Soni

Turkish Journal of Electrical Engineering and Computer Sciences

The Field Programmable Gate Array (FPGA) is an on field programmable device which can be designed for different applications. Various types of software are available for its synthesis. The cell placement depends upon the designing and programming languages used for FPGA. In this paper cell placement technique of FPGA architecture is analyzed for the application of Space Vector Pulse Width Modulation (SVPWM) technique used in speed control of an induction motor. The modulation pulses are produced due to the various components activated and their interconnection in Configurable Logic Blocks (CLBs). Few of its components are so analyzed to find out …


New Esd Standard And Influence On Test Equipment Requirements, Nicholas Wright Jan 2009

New Esd Standard And Influence On Test Equipment Requirements, Nicholas Wright

Turkish Journal of Electrical Engineering and Computer Sciences

The IEC61000-4 series of standards form a basic framework for the immunity and emissions testing of electrical and electronic equipment. They are the basis for EN standards used to test CE compliance of electrical and electronic products sold within the European Union. After a period of relative stability, changes are being introduced, designed to improve reliable application of the basic standards and ensure that the same results are obtained no matter where the tests are performed. Many changes relate to the calibration procedures for the test equipment. The surge standard, IEC61000-4-5, was revised at Edition 2 to amend impulse performance …


Parameter Identification Of A Separately Excited Dc Motor Via Inverse Problem Methodology, Mounir Hadef, Mohamed Rachid Mekideche Jan 2009

Parameter Identification Of A Separately Excited Dc Motor Via Inverse Problem Methodology, Mounir Hadef, Mohamed Rachid Mekideche

Turkish Journal of Electrical Engineering and Computer Sciences

Identification is considered to be among the main applications of inverse theory and its objective for a given physical system is to use data which is easily observable, to infer some of the geometric parameters which are not directly observable. In this paper, a parameter identification method using inverse problem methodology is proposed. The minimisation of the objective function with respect to the desired vector of design parameters is the most important procedure in solving the inverse problem. The conjugate gradient method is used to determine the unknown parameters, and Tikhonov's regularization method is then used to replace the original …


A Covert Encryption Method For Applications In Electronic Data Interchange, Jonathan Blackledge, Dmitry Dubovitskiy Jan 2009

A Covert Encryption Method For Applications In Electronic Data Interchange, Jonathan Blackledge, Dmitry Dubovitskiy

Articles

A principal weakness of all encryption systems is that the output data can be ‘seen’ to be encrypted. In other words, encrypted data provides a ‘flag’ on the potential value of the information that has been encrypted. In this paper, we provide a new approach to ‘hiding’ encrypted data in a digital image.

In conventional (symmetric) encryption, the plaintext is usually represented as a binary stream and encrypted using an XOR type operation with a binary cipher. The algorithm used is ideally designed to: (i) generate a maximum entropy cipher so that there is no bias with regard to any …


Pca Based Protection Algorithm For Transformer Internal Faults, Erdal Kiliç, Okan Özgönenel, Ömer Usta, Dave Thomas Jan 2009

Pca Based Protection Algorithm For Transformer Internal Faults, Erdal Kiliç, Okan Özgönenel, Ömer Usta, Dave Thomas

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a new protection scheme is introduced to detect and identify transformer winding faults. The new approach is based on artificial neural networks (ANNs) using radial basis functions (RBFs) and the principal component analysis (PCA). The nonlinear system's input and output data is manipulated without considering any model of the system. This approach is used to detect and identify internal short circuit faults of a three phase custom built transformer. The suggested technique is also able to distinguish between the fault and magnetizing inrush current. The test studies carried out shows that the proposed method leads to satisfactory …


Multicast Encryption Infrastructure For Security In Sensor Networks, Richard R. Brooks, Brijesh Pillai, Matthew Pirretti, Michele C. Weigle Jan 2009

Multicast Encryption Infrastructure For Security In Sensor Networks, Richard R. Brooks, Brijesh Pillai, Matthew Pirretti, Michele C. Weigle

Computer Science Faculty Publications

Designing secure sensor networks is difficult. We propose an approach that uses multicast communications and requires fewer encryptions than pairwise communications. The network is partitioned into multicast regions; each region is managed by a sensor node chosen to act as a keyserver. The keyservers solicit nodes in their neighborhood to join the local multicast tree. The keyserver generates a binary tree of keys to maintain communication within the multicast region using a shared key. Our approach supports a distributed key agreement protocol that identifies the compromised keys and supports membership changes with minimum system overhead. We evaluate the overhead of …


Graphical User Interfaces As Updatable Views, James Felger Terwilliger Jan 2009

Graphical User Interfaces As Updatable Views, James Felger Terwilliger

Dissertations and Theses

In contrast to a traditional setting where users express queries against the database schema, we assert that the semantics of data can often be understood by viewing the data in the context of the user interface (UI) of the software tool used to enter the data. That is, we believe that users will understand the data in a database by seeing the labels, dropdown menus, tool tips, help text, control contents, and juxtaposition or arrangement of controls that are built in to the user interface. Our goal is to allow domain experts with little technical skill to understand and query …


Semantics Enriched Service Environments, Karthik Rajagopal Gomadam Jan 2009

Semantics Enriched Service Environments, Karthik Rajagopal Gomadam

Browse all Theses and Dissertations

During the past seven years services centric computing has emerged as the preferred approach to architect complex software. Software is increasingly developed by integrating remotely existing components, popularly called services. This architectural paradigm, also called Service Oriented Architecture (SOA), brings with it the benefits of interoperability, agility and flexibility to software design and development. One can easily add or change new features to existing systems, either by the addition of new services or by replacing existing ones. Two popular approaches have emerged for realizing SOA. The first approach is based on the SOAP protocol for communication and the Web Service …


Hierarchical Routing In Manets Using Simple Clustering, Adam Carnine Jan 2009

Hierarchical Routing In Manets Using Simple Clustering, Adam Carnine

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis presents both a review of current MANET routing protocols and a new MANET routing algorithm. The routing protocols reviewed include representative samples from the three primary forms of routing found in MANETS: proactive routing, reactive routing and hybrid routing. Secure algorithms are given special treatment in the review. In addition several protocol enhancements are discussed.

The proposed routing protocol is designed to support networks of a medium size, containing over 200 nodes but less than 3,000 nodes. The design is intentionally simple to allow ease of implementation in comparison with other MANET protocols that provide similar functionality.


Burst Scheduling, Grooming And Qos Provisioning In Optical Burst-Switched Networks, Yuqi Fan Jan 2009

Burst Scheduling, Grooming And Qos Provisioning In Optical Burst-Switched Networks, Yuqi Fan

Browse all Theses and Dissertations

The demand of network capacity has been increasing steadily with more users than ever connected to the Internet through broadband access and the popularity of video based applications, such as YouTube. Optical wavelength division multiplexing (WDM) networks are expected to form the next-generation backbone network and to fulfill the insatiable appetite for bandwidth.

Wavelength routed WDM optical networks offer the granularity of switching at a fiber, waveband, or a wavelength level. The finest granularity offered is at a wavelength level by provisioning lightpaths for different clients/services. All-optical packet switching is still deemed technically infeasible and its competitiveness as a backbone …


Improving Remote Homology Detection Using A Sequence Property Approach, Gina Marie Cooper Jan 2009

Improving Remote Homology Detection Using A Sequence Property Approach, Gina Marie Cooper

Browse all Theses and Dissertations

Understanding the structure and function of proteins is a key part of understanding biological systems. Although proteins are complex biological macromolecules, they are made up of only 20 basic building blocks known as amino acids. The makeup of a protein can be described as a sequence of amino acids. One of the most important tools in modern bioinformatics is the ability to search for biological sequences (such as protein sequences) that are similar to a given query sequence. There are many tools for doing this (Altschul et al., 1990, Hobohm and Sander, 1995, Thomson et al., 1994, Karplus and Barrett, …


Semantic And Role-Based Access Control For Data Grid Systems, Vineela Muppavarapu Jan 2009

Semantic And Role-Based Access Control For Data Grid Systems, Vineela Muppavarapu

Browse all Theses and Dissertations

A Grid is an integration infrastructure for sharing and coordinated use of diverseresources in dynamic, distributed virtual organizations (VOs). A Data Grid is an architecture for the access, exchange, and sharing of data in the Grid environment. Distributed data resources can be diverse in their formats, schema, quality, access mechanisms, ownership, access policies, and capabilities. In recent years, several organizations have started utilizing Grid technologies to deploy data-intensive and/or computation-intensive applications. As more and more organizations are sharing data resources and participating in Data Grids, the complexity and heterogeneity of the systems is increasing constantly, but their management techniques are …


Design And Performance Analysis Of A Secure Proces-Sor Scan-Sp With Crypto-Biometric Capabilities, Raghudeep Kannavara Jan 2009

Design And Performance Analysis Of A Secure Proces-Sor Scan-Sp With Crypto-Biometric Capabilities, Raghudeep Kannavara

Browse all Theses and Dissertations

Secure computing is gaining importance in recent times as computing capability is increasingly becoming distributed and information is everywhere. Prevention of piracy and digital rights management has become very important. Information security is mandatory rather than an additional feature. Numerous software techniques have been proposed to provide certain level of copyright and intellectual property protection. Techniques like obfuscation attempt to transform the code into a form that is harder to reverse engineer. Tamper-proofing causes a program to malfunction when it detects that it has been modified. Software watermarking embeds copyright notice in the software code to allow the owners of …


A Cryptanalysis Methodology For The Reverse Engineering Of Encrypted Information In Images, Allan Anthony Rwabutaza Jan 2009

A Cryptanalysis Methodology For The Reverse Engineering Of Encrypted Information In Images, Allan Anthony Rwabutaza

Browse all Theses and Dissertations

Security is an important issue related to the storage and communication of data and information. In data and information security, cryptography and steganography are two of the most common security techniques. On one hand, there is cryptography, which is the secret communication between two parties by message scrambling on the sender's side and message unscrambling on the receiver's side so that only the intended receiver gets the secret message. On the other hand, there is steganography, which is the hiding of information in a medium in such a way that no one other than the sender or the intended receiver …


Tyflos: A Wearable Navigation Prototype For Blind & Visually Impaired; Design, Modelling And Experimental Results, Dimitrios Dakopoulos Jan 2009

Tyflos: A Wearable Navigation Prototype For Blind & Visually Impaired; Design, Modelling And Experimental Results, Dimitrios Dakopoulos

Browse all Theses and Dissertations

The need for assistive devices has, had and will have a large merit in many engineering research arenas. This dissertation deals with the design, modeling, implementation and experimentation of the navigation component of a wearable assistive system for blind and visually impaired people, called TYFLOS (ΤΥΦΛΟΣ) which is the Greek word for "Blind".

The current prototype consists of two mini cameras attached to a pair of conventional eye-glasses, a 2D tactile display vibration array) which consists of 16 vibrating elements arranged in a 4x4 manner, attached to an elastic vest worn on the user's abdomen, a portable computer, an ear-speaker …


Computational Techniques For Reducing Spectra Of The Giant Planets In Our Solar System, Holly L. Grimes Jan 2009

Computational Techniques For Reducing Spectra Of The Giant Planets In Our Solar System, Holly L. Grimes

Dissertations and Theses

The dynamic atmospheres of Jupiter, Saturn, Uranus, and Neptune provide a rich source of meteorological phenomena for scientists to study. To investigate these planets, scientists obtain spectral images of these bodies using various instruments including the Cooled Mid-Infrared Camera and Spectrometer (COMICS) at the Subaru Telescope Facility at Mauna Kea, Hawaii. These spectral images are two-dimensional arrays of double precision floating point values that have been read from a detector array. Such images must be reduced before the information they contain can be analyzed. The reduction process for spectral images from COMICS involves several steps:

1. Sky subtraction: the …