Computer Sciences Commons^™

Analysis Of High Performance Scientific Programming Workflows, Withana Kankanamalage Umayanganie Klaassen

Open Access Theses & Dissertations

Substantial time is spent on building, optimizing and maintaining large-scale software that is run on supercomputers. However, little has been done to utilize overall resources efficiently when it comes to including expensive human resources. The community is beginning to acknowledge that optimizing the hardware performance such as speed and memory bottlenecks contributes less to the overall productivity than does the development lifecycle of high-performance scientific applications. Researchers are beginning to look at overall scientific workflows for high performance computing. Scientific programming productivity is measured by time and effort required to develop, configure, and maintain a simulation experiment and its constituent …

Self-Image Multimedia Technologies For Feedforward Observational Learning, Nkiruka M. A. Uzuegbunam

Theses and Dissertations--Electrical and Computer Engineering

This dissertation investigates the development and use of self-images in augmented reality systems for learning and learning-based activities. This work focuses on self- modeling, a particular form of learning, actively employed in various settings for therapy or teaching. In particular, this work aims to develop novel multimedia systems to support the display and rendering of augmented self-images. It aims to use interactivity (via games) as a means of obtaining imagery for use in creating augmented self-images. Two multimedia systems are developed, discussed and analyzed. The proposed systems are validated in terms of their technical innovation and their clinical efficacy in …

High-Order Integral Equation Methods For Quasi-Magnetostatic And Corrosion-Related Field Analysis With Maritime Applications, Robert Pfeiffer

Theses and Dissertations--Electrical and Computer Engineering

This dissertation presents techniques for high-order simulation of electromagnetic fields, particularly for problems involving ships with ferromagnetic hulls and active corrosion-protection systems.

A set of numerically constrained hexahedral basis functions for volume integral equation discretization is presented in a method-of-moments context. Test simulations demonstrate the accuracy achievable with these functions as well as the improvement brought about in system conditioning when compared to other basis sets.

A general method for converting between a locally-corrected Nyström discretization of an integral equation and a method-of-moments discretization is presented next. Several problems involving conducting and magnetic-conducting materials are solved to verify the accuracy …

Average Modeling And Evaluation Of 18-Pulse Autotransformer Rectifier Unit Without Interphase Transformers, Shahbaz Khan, Xiaobin Zhang, Husan Ali, Haider Zaman, Muhammad Saad, Bakht Muhammad Khan

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an improved average model and evaluation of an 18-pulse autotransformer rectifier unit (ATRU) in differential delta configuration. Average models remove the switching behavior of diode rectifiers and high bandwidth transients, which not only facilitates simulation of power systems by reducing computational cost but also enables impedance-based stability analysis for large complex power systems. To experimentally validate the proposed average model, a 2-kW, 18-pulse ATRU has been tested and the results of the derived model are compared with those of the switching model and experimental prototype. Computed transfer function of load impedance from the proposed average model closely …

A Novel Multistage System For The Detection And Removal Of Pectoral Muscles Inmammograms, İdi̇l Işikli Esener, Semi̇h Ergi̇n, Tolga Yüksel

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a novel multistage scheme for pectoral muscle removal from mammography images is proposed, and the performance of this system is verified using the publicly available Mammographic Image Analysis Society digital mammogram database. This database is composed of mediolateral oblique mammography images including three different tissue types (fatty, fatty-glandular, and dense-glandular) with three health status types (normal, benign cancer, and malignant cancer). In the implementation of the proposed system, a mammography image is first preprocessed by performing noise reduction background removal followed by artifact suppression processes. Then a presegmentation procedure is applied using region growing and line fitting …

Multimodal Medical Imaging Repository And Information System In Epilepsysurgery, Gülsüm Akdeni̇z, İbrahi̇m Atli, Fati̇h Vehbi̇ Çelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Surgery is an option for patients with drug-resistant epilepsy, but it requires a comprehensive assessment. Electroencephalography (EEG), magnetic resonance imaging (MRI), and functional MRI (fMRI) are used to localize the epileptogenic zone, which directly affects the surgery outcome. Accessing EEG, MRI, and fMRI results and patient information simultaneously using traditional methods might result in misinformation and increase the workload of clinicians. In this study, we developed a modern web-based repository system for the preoperative evaluation of epilepsy disorder, including multimodal medical images and patient information. Our dedicated system is enriched with clinical metadata that are not currently available and is …

Energy-Efficient And Reliable Data Collection In Wireless Sensor Networks, Deepa Puneeth, Nishanth Joshi, Pradeep Kumar Atrey, Muralidhar Kulkarni

Turkish Journal of Electrical Engineering and Computer Sciences

Ensuring energy efficiency, data reliability, and security is important in wireless sensor networks (WSNs). A combination of variants from the cryptographic secret sharing technique and the disjoint multipath routing scheme is an effective strategy to address these requirements. Although Shamir's secret sharing (SSS) provides the desired reliability and information-theoretic security, it is not energy efficient. Alternatively, Shamir's ramp secret sharing (SRSS) provides energy efficiency and data reliability, but is only computationally secure. We argue that both these approaches may suffer from a compromised node (CN) attack when a minimum number of nodes is compromised. Hence, we propose a new scheme …

Improved Discrete Sliding Mode Control Strategy For Pulse-Width Modulationrectifier, Jing Cao, Chaonan Tong

Turkish Journal of Electrical Engineering and Computer Sciences

An improved sliding mode control utilizing repetitive control (ISMRC) is proposed for a three-phase pulse- width modulation (PWM) rectifier. The proposed controller integrates the advantages of both sliding mode control (SMC) and repetitive control (RC) by implementing a structure that embeds an RC controller into the equivalent control branch of an SMC controller. Both a simulation and an experiment are conducted to compare the proposed ISMRC controller with a conventional SMC controller. It is demonstrated that the fifth harmonic distortion of the current of the PWM rectifier system is controlled at 3.3%, the power factor is close to the unit, …

Usage Of Segmentation For Noise Elimination In Reconstructed Images In Digitalholographic Interferometry, Gülhan Ustabaş Kaya, Zehra Saraç

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we propose to enhance the image in digital holography by using an artificial neural network and an iterative algorithm with Nakamura's approach based on segmentation. It is well known that reconstructed three- dimensional (3D) images suffer from noise in digital holography. In addition, obtaining 3D reconstructed images takes a long time due to large pixel numbers in reconstructed images and lack of memory in the system. The segmentation process is an application that overcomes these problems. Therefore, we focus on the implementation of segmentation for image enhancement. In addition, the results of the segmentation process for both …

An Investigation On Characteristics Of Tracking Failure In Epoxy Resin Withharmonic And Fractal Dimension Analysis, Mehmet Murat İspi̇rli̇, Aysel Ersoy Yilmaz

Turkish Journal of Electrical Engineering and Computer Sciences

Epoxy resins have excellent mechanical and electrical properties; thus, they are commonly preferred in the electrical{electronic sector as insulation materials. These insulation materials experience degradation such as breakdown, tracking, or treeing. Therefore, safety and reliability tests of insulation materials have great importance in estimating the performance of insulation. These tests must be carried out to decrease the risk of electrical insulation fault. In this study, the relationship between tracking failures and the data obtained during experiments was evaluated. Tracking failure performance of epoxy resin was investigated using the IEC 60112 test standard, which is known as the comparative tracking index …

New Results On The Global Asymptotic Stability Of Certain Nonlinear Rlc Circuits, Muzaffer Ateş, Sami̇ra Lari̇bi̇

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with the global asymptotic stability (GAS) of certain nonlinear RLC circuit systems using the direct Lyapunov method. For each system a suitable Lyapunov function or energy-like function is constructed and the direct Lyapunov method is applied to the related system. Then the invariant equilibrium point of each system that makes the system solution to the global asymptotic stable is determined. Some new explicit GAS conditions of certain nonlinear RLC circuit systems are derived by Lyapunov's direct method. The presented simulations are compatible with the new results. The results are given with proofs.

Damping Wide-Area Oscillations In Power Systems: A Model Predictive Controldesign, Emrah Biyik, Munir Husein

Turkish Journal of Electrical Engineering and Computer Sciences

Electromechanical oscillations in power systems have been observed ever since synchronous generators were interconnected to provide reliability and higher generation capacity, and they have become a severe threat for the safe and economic operation of modern interconnected power grids. To dampen these oscillations, wide-area damping controllers (WADCs) have been introduced by utilizing wide-area measurement systems and synchronized phasor measurement units. In this paper, we present a systematic approach for designing WADCs using a model predictive control (MPC) technique to damp interarea oscillations in the power system. The MPC controller computes optimal control signals for the excitation system of a remote …

Rlgc(F) Modeling Of A Busbar Distribution System Via Measured S-Parameters Atcenelec And Fcc Bands, Zeynep Hasirci, İsmai̇l Hakki Çavdar, Mehmet Öztürk

Turkish Journal of Electrical Engineering and Computer Sciences

This paper addresses the extraction of accurate frequency-dependent per-unit-length RLGC parameters for busbar distribution systems using measured S-parameters for the CENELEC and FCC bands. A busbar is a distribution system element (three phase, low voltage) with a modular structure that carries electrical energy in buildings. The S-parameters of a busbar distribution system at different current levels (630 A, 1250 A, 2000 A) are measured with a vector network analyzer and then analyzed for three different two-port connections (L1-N, L2-N, L3-N). A frequency- dependent RLGC(f) model is used to characterize the busbar as a transmission line using a derivative-free optimization algorithm. …

Analysis Of Ground Return Impedance Calculation Methods For Modeling Ofunderground Cables For Lightning Studies, Meli̇h Güneri̇, Bora Alboyaci

Turkish Journal of Electrical Engineering and Computer Sciences

Analysis of lightning transients in cable systems necessitates accurate calculation of ground return impedances (GRIs) in high-frequency regions. EMT-type programs used for transient analyses incorporate various methods for calculation of GRI. Most of these methods include assumptions and approximations, the validity of which needs to be questioned at high frequencies. In particular, the common approximation of the neglecting effect of displacement currents should be reviewed. The purpose of this paper is to evaluate commonly used GRI calculation methods in terms of their accuracy and validity in high-frequency regions. In this study, GRI calculation methods are analyzed and compared, the effect …

A New Semianalytical Method For Analysis Of The Disc-Type Permanent Magnethysteresis Motor In Steady-State Operational Conditions, Ali Behniafar, Ahmad Darabi

Turkish Journal of Electrical Engineering and Computer Sciences

Considering the characteristics of hysteresis and permanent magnet motors, it seems that these two motors are complements of each other. Thus, their combination yields a motor with an excellent performance. In order to preserve the major advantages of both motors in the new motor, a disc-type slotless structure is chosen. This paper presents a new finite-element method for the modeling of disc-type permanent magnet hysteresis synchronous (PMHS) motor. In this modeling method a new iterative algorithm is used. Programming software has been linked to finite- element software because of its limitation in the modeling of hysteresis phenomena. Validity of the …

Indoor Localization Of Wireless Emitter Using Direct Position Determination And Particle Swarm Optimization, Saeid Hassanhosseini, Mohammad Reza Taban, Jamshid Abouei

Turkish Journal of Electrical Engineering and Computer Sciences

Many methods are introduced to accomplish determining the position of emitters with respect to known-position receivers in indoor localizations. Among them, the direct position determination (DPD) approach advocates using the received signals by all the base stations together in order to estimate the locations in a single step. However, DPD is not very accurate due to the use of a gridding area, the effect of noise, and the multipath phenomenon. In order to improve the DPD performance, we derive an analytic model based on weighted least square estimation that uses simultaneously the effect of delay, Doppler, attenuation, and angle of …

Brain-Computer Interface: Controlling A Robotic Arm Using Facial Expressions, Humaira Nisar, Hong-Way Khow, Kim Ho Yeap

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this paper is to develop a brain-computer interface (BCI) system that can control a robotic arm using EEG signals generated by facial expressions. The EEG signals are acquired using a neurosignal acquisition headset. The robotic arm consists of a 3-D printed prosthetic hand that is attached to a forearm and elbow made of craft wood. The arm is designed to make four moves. Each move is controlled by one facial expression. Hence, four different EEG signals are used in this work. The performance of the BCI robotic arm is evaluated by testing it on 10 subjects. Initially …

Highly Accurate And Sensitive Short Read Aligner, Mehmet Yağmur Gök, Sezer Gören Uğurdağ, Cem Ünsalan, Mahmut Şami̇l Sağiroğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Next-generation sequencing generates large numbers of short reads from DNA. This makes it difficult to process and store. Therefore, efficient sequence alignment and mapping techniques are needed in bioinformatics. Alignment and mapping are the basic steps involved in genetic data analysis. The Smith-Waterman (SW) algorithm, a well-known dynamic programming algorithm, is often used for this purpose. In this work, we propose to utilize Phred quality scores in Gotoh's affine gap model to increase the accuracy and sensitivity of the SW algorithm. Hardware platforms such as FPGAs and GPUs are commonly used to solve computationally expensive problems. In this work, a …

Classification Of Surface Electromyogram Signals Based On Directed Acyclic Graphs And Support Vector Machines, Xinhui Hu, Jiangming Kan, Wenbin Li

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel classification approach for surface electromyogram (sEMG) signals. The proposed classification approach involves two steps: (1) feature extraction from an sEMG, in which a 7-dimensional feature vector is extracted from 27 types of features of the sEMG by linear discriminant analysis (LDA), and (2) a novel classifier, DAGSVMerr, based on a directed acyclic graph (DAG) and support vector machine (SVM), in which a separability measure function based on erroneous recognition rates (ERRs) is defined to determine the initial operation list. The proposed approach takes advantage of the feedback idea to improve the performance of the classification. …

An Efficient Technique Based On Firefly Algorithm For Pilot Design Process In Ofdm-Idma Systems, Necmi̇ Taşpinar, Şaki̇r Şi̇mşi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

Accurate placement of pilot tones has been a crucial task in multicarrier transmission technologies since there is a strong relation between pilot positions and channel estimation performance. Therefore, the firefly algorithm (FA) is proposed for achieving the optimal pilot distribution by optimizing the pilot positions in order to minimize the estimation errors of the least squares algorithm employed in orthogonal frequency division multiplexing-interleave division multiple access (OFDM-IDMA) systems. According to the simulation results, our proposed FA-based pilot optimizer provides a great performance increase in OFDM-IDMA systems by obtaining the most appropriate pilot distribution pattern among the considered pilot placement strategies. …

Schedulability Test For Ima Systems Based On Mixed Integer Linear Programming Formulation, Yukai Hao, Ming Mu, Xiaodi Dai, Xiangdong Li

Turkish Journal of Electrical Engineering and Computer Sciences

Integrated modular avionics (IMA) architecture is widely adopted for the design of modern aircraft. It simplifies the system development process and improves the system security and reliability. In IMA systems, avionics applications are packed into various partitions, and integrated into a standard computing platform. How to determine the schedulability of systems is one of the key problems. In this paper, using the characters of avionics systems, a partition model with a strict period is built, and constraints in space, time, and communication are analyzed. Based on the mixed integer linear programming formulation, a solution to determine the schedulability of IMA …

Nonlinear Analysis Of Hybrid Phase-Controlled Systems In Z-Domain With Convex Lmi Searches, Nur Syazreen Ahmad, Pei Ni Goh

Turkish Journal of Electrical Engineering and Computer Sciences

Phase-controlled systems such as phase-locked loops (PLLs) have been used in numerous applications ranging from data communications to speed motor control. The hybrid case where only the phase detector is digital while others are analog has advantages over the classical PLLs in the sense that it provides a wider locking range and is more suitable when the input and output signals come in digital waveforms. Although such systems are inherently nonlinear due to the phase detector's characteristics, the nonlinearity is often bypassed in order to ease the analysis and design methods. This, however, will give erroneous results when the phase …

Modeling Of Realistic Heart Electrical Excitation Based On Dti Scans And Modified Reaction Diffusion Equation, Ihab Elaff

Turkish Journal of Electrical Engineering and Computer Sciences

A new method is proposed for modeling realistic heart activation using diffusion tensor imaging (DTI) scans based on biological properties of its tissues in addition to the working methodology of the DTI scanner. Modeling of the excitation propagation inside the heart is initiated by applying activation at only one pacing site at the root of the conduction network. The excitation propagation has been accomplished based on a proposed conduction system that is extracted from DTI heart scans and a modified version of monodomain reaction diffusion equation (RDE) that considers the heart inhomogeneous--anisotropic material. The Aliev--Panfilov method was used to model …

Compact Local Gabor Directional Number Pattern For Facial Expression Recognition, Zhengyan Zhang, Guanming Lu, Jingjie Yan, Haibo Li, Ning Sun, Xia Li

Turkish Journal of Electrical Engineering and Computer Sciences

This paper explores a novel method to represent face images for facial expression recognition; it is named compact local Gabor directional number pattern (CLGDNP). By convolving the face images with Gabor filters, we encode the magnitude and phase response images in each scale, and calculate the histograms in several nonoverlapping regions of each encoded image. Finally, we obtain two spatial histogram sequences by the aid of the mean pooling technology and concatenate them to form the facial descriptor. Moreover, for evaluating the performance of the proposed method, we employ a support vector machine to conduct some extensive classification experiments on …

Will It Pass? Predicting The Outcome Of A Source Code Review, Çağdaş Evren Gerede, Zeki̇ Mazan

Turkish Journal of Electrical Engineering and Computer Sciences

It has been observed that allowing source code changes to be made only after source code reviews has a positive impact on the quality and lifetime of the resulting software. In some cases, code review processes take quite a long time and this negatively affects software development costs and employee job satisfaction. Establishing mechanisms that predict what kind of feedback reviewers will provide and what revisions they will ask for can reduce the number of times this problem occurs. Thanks to such mechanisms, developers can improve the maturity of their code change requests before the review process starts. In this …

High-Speed Data Deduplication Using Parallelized Cuckoo Hashing, Jane Rubel Angelina Jeyaraj, Sundarakantham Kambaraj, Velmurugan Dharmarajan

Turkish Journal of Electrical Engineering and Computer Sciences

Data deduplication is a capacity optimization technology used in backup systems for identifying and storing the nonredundant data blocks. The CPU intensive tasks involved in a hash-based deduplication system remain as challenges in improving the performance of the system. In this paper, we propose a parallel variant of the standard cuckoo hashing that enables the hashing technique to be performed in parallel. The CPU intensive tasks of fingerprint insertion and lookup operations are performed in parallel and distributed among the nodes of the deduplication cluster. Furthermore, the uniform handling of the blocks by the cluster nodes involved in the process …

Virtual Force-Based Intelligent Clustering For Energy-Efficient Routing In Mobile Wireless Sensor Networks, Selvi Munuswamy, Jothi Muneeswari Saravanakumar, Ganapathy Sannasi, Khanna Nehemiah Harichandran, Kannan Arputharaj

Turkish Journal of Electrical Engineering and Computer Sciences

A mobile wireless sensor network (MWSN) consists of many sensor nodes, which can move from one position to another and gather data from the environment, and such nodes are coordinated with the support of a sink node. In recent years, the mobility behavior of sensor nodes present in wireless sensor networks is used to form effective clustering and to perform cluster-based routing. Virtual force is an important phenomenon in sensor nodes, which is used to model the mobility behavior. Production rules that use spatiotemporal constraints are able to make more accurate decisions on mobility speed, mobility area, and the required …

Probabilistic Dynamic Security Assessment Of Large Power Systems Using Machine Learning Algorithms, Sevda Jafarzadeh, Veysel Murat İstemi̇han Genç

Turkish Journal of Electrical Engineering and Computer Sciences

Arrhythmia, also known as dysrhythmia, is a condition involving an irregular heartbeat. A problem in the heart may cause problems in other organs, and as time passes, this will lead to more severe problems. Arrhythmia must be detected at an early stage to prevent such a problem occurring in the heart. Detection of arrhythmia from an electrocardiogram is an easy method that does not need much equipment and does not harm the patient. The purpose of this research is to find a faster and more accurate system to classify nine classes of arrhythmia. The St. Petersburg Institute of Cardiological Technics …

The Application Of Analytical Mechanics In A Multimachine Power System, Zhijie Wang, Zhiyuan Liu, Jie Wang, Xiuchen Jiang, Sanming Liu, Yifang Liu, Gehao Sheng, Tianyu Liu

Turkish Journal of Electrical Engineering and Computer Sciences

Analytical mechanics methods play an important role in determining the energy function and Hamilton realization of a system. In this paper, the Hamilton function of the system is obtained directly from the system differential equation by means of analytical mechanics. In addition, the system Hamiltonization process requires that the system must be even order, and the commonly used generator model is a single-axis third-order model. For this reason, the odd-order power system model is extended to an even-order system. The Hamilton function of the system is deduced with coordinate transformation and the generalized force. Then the standard form of Hamilton …

Conception And Control Of A Wtgs System Using A Novel Control Technique Based On Mpc-Dpc-Mvf With A Switch Optimization Process, Mansour Madaci, Djallel Kerdoun

Turkish Journal of Electrical Engineering and Computer Sciences

The work proposed through this paper presents a novel technique applied for the control of a wind turbine generation system (WTGS) prototype. A model predictive control combined with a direct power control technique (MPC-DPC) based on SVM control and a novel switching cycle sequence pattern for thermal switch losses reduction have been adopted. The novel developed direct power control (DPC) scheme based on a multivariable filter (MVF) topology for power estimation process has been illustrated. The control of the converter system is adopted through a predictive control strategy to achieve a complete and an instantaneous control over the active and …