Computer Engineering Commons^™

A Neural-Based Electromagnetic Inverse Scattering Approach To The Detection Of A Conducting Cylinder Coated With A Dielectric Material, Senem Makal, Ahmet Kizilay

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a radial basis function neural network approach is applied for the estimation of the localization and the radius of a conducting cylinder with a circular cross-section coated with a dielectric material. A set of features, the radar cross-section (RCS) values, are derived from scattered fields, which are calculated using the surface equivalence principle and the method of moment. RCS values are obtained using 10 different scattering angles that are fed into the network. The outputs of the network are the location (x_0, y_0) and the radius (r_p) of the conducting cylinder. This is an application of the …

Considering Transmission Loss For An Economic Dispatch Problem Without Valve-Point Loading Using An Ep-Epso Algorithm, Sevugarathinam Muthu Vijaya Pandian, Keppanagowder Thanushkodi

Turkish Journal of Electrical Engineering and Computer Sciences

Economic dispatch (ED) is one of the most important optimization problems in a power system. The objective of ED is sharing the power demand among the online generators while keeping the minimum cost of generation as a constraint. The aim of this paper is to operate an electric power system as economically as possible within its security limits. This paper proposes the following 2 new particle swarm optimization (PSO) algorithms to solve a nonconvex economic dispatch problem: an efficient PSO is termed as efficient particle swarm optimization (EPSO), and a hybrid of evolutionary programming (EP) and EPSO is termed as …

Resolution Enhancement Of Video Sequences By Using Discrete Wavelet Transform And Illumination Compensation, Sara Izadpanahi, Çağri Özçinar, Gholamreza Anbarjafari, Hasan Demirel

Turkish Journal of Electrical Engineering and Computer Sciences

This research paper proposes a new technique for video resolution enhancement that employees an illumination compensation procedure before the registration process. After the illumination compensation process, the respective frames are registered using the Irani and Peleg technique. In parallel, the corresponding frame is decomposed into high-frequency (low-high, high-low, and high-high) and low-frequency (low-low) subbands using discrete wavelet transform (DWT). The high-frequency subbands are superresolved using bicubic interpolation. Afterwards, the interpolated high-frequency subbands and superresolved low-frequency subband obtained by registration are used to construct the high-resolution frame using inverse DWT. The superiority of the proposed resolution enhancement method over well-known video …

Model Selection And Score Normalization For Text-Dependent Single Utterance Speaker Verification, Osman Büyük, Mustafa Levent Arslan

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we investigate model selection and channel variability issues on a text-dependent single utterance (TDSU) speaker verification application. Due to the lack of an appropriate database for the task, a multichannel speaker recognition database, which consists of multiple recordings of a single Turkish utterance, is collected. The first set of experiments is devoted to model selection. Phonetic hidden Markov model (HMM)-based, sentence HMM-based, and Gaussian mixture model (GMM)-based methods are compared to find the most appropriate modeling approach for the target application. Based on the experimental results, the HMM-based methods outperform the GMM. The sentence HMM yields the …

Using A Game-Based Learning Model As A New Teaching Strategy For Computer Engineering, Kristijan Kuk, Dragica Jovanovic, Dusan Jokanovic, Petar Spalevic, Marko Caric, Stefan Panic

Turkish Journal of Electrical Engineering and Computer Sciences

Interactive multimedia simulations and computer game elements can be successfully combined in order to create new advanced educational resources for teaching today's generation of students. Such a learning environment, a game-based learning model (GBLm), has been designed as a research prototype. This paper describes one type of GBLm for computer engineering, which we have used in the subject of computer graphics for the teaching unit Z-buffer algorithm, in order to facilitate the learning process. The implementation of a GBLm for graphical algorithms (GBL4CAl) is presented in detail as a multimedia interactive learning module designed to motivate students by making learning …

On The Degradation Of Ota-C--Based Cmos Low-Power Filter Circuits For Biomedical Instrumentation, Yasi̇n Özçelep, Ayten Kuntman, Hulusi̇ Hakan Kuntman

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, we propose a degraded transistor-based circuit degradation simulation method to investigate the degradation effect in complementary metal-oxide semiconductor (CMOS) biomedical devices. The method is demonstrated on an operational transconductance amplifier and capacitor (OTA-C)-based CMOS filter structure. First, we simulate the degradation of the symmetrical CMOS OTA by determining the degraded transistors in the structure. The simulation results are compared with the experimental results of our previous study. First- and second-order low-pass filter degradations are also simulated to demonstrate the accuracy of the proposed method. Finally, the degradation in the electroencephalogram band-pass filter and its effect on the …

Adaptive Optimization Of Edca Parameters For Improved Qos In Multi-Media Applications, Alparslan Çi̇l, Mehmet Akar, Emi̇n Anarim

Turkish Journal of Electrical Engineering and Computer Sciences

IEEE 802.11e Enhanced Distributed Channel Access (EDCA) has been incorporated into the standard as an effective medium access mechanism in order to provide the desired QoS for multimedia applications such as VoIP and IPTV. This paper presents an adaptive optimization algorithm in EDCA which strives to provide improved QoS from both delay and throughput perspectives. As a first step towards this goal, a Markov model of the EDCA mechanism has been introduced, which is subsequently used to compute the estimates of throughput and delay. Based on the analytical model that is validated via real-time simulations in OPNET, a new algorithm …

Hybrid Mpi+Upc Parallel Programming Paradigm On An Smp Cluster, Zeki̇ Bozkuş

Turkish Journal of Electrical Engineering and Computer Sciences

The symmetric multiprocessing (SMP) cluster system, which consists of shared memory nodes with several multicore central processing units connected to a high-speed network to form a distributed memory system, is the most widely available hardware architecture for the high-performance computing community. Today, the Message Passing Interface (MPI) is the most widely used parallel programming paradigm for SMP clusters, in which the MPI provides programming both for an SMP node and among nodes simultaneously. However, Unified Parallel C (UPC) is an emerging alternative that supports the partitioned global address space model that can be again employed within and across the nodes …

Improved Computerized Evaluation Of Abdominal Aortic Aneurysm, Semi̇h Utku, Hulusi̇ Baysal, Reyat Yilmaz, Aytaç Gülcü, Recep Alp Kut, Ahmet Yi̇ği̇t Göktay

Turkish Journal of Electrical Engineering and Computer Sciences

Accurate measurements of arterial anatomy are emerging as the most important determinants of endovascular abdominal aneurysm repair. It is quite difficult to define and measure arterial anatomy features quantitatively due to the complex structure of the aneurysm and insufficient visual feedback. During decision making, to assist operators in diagnosing abdominal aortic aneurysms, a specialized preprocessing Abdominal Aortic Aneurysm Measurement and Evaluation Tool (AMET) was developed. AMET provides visual interfaces with broad measurement capabilities to generate a 3D model of the aorta for a better diagnosis and accurate stent selection. The accuracy and usability of the tool was tested with a …

Simultaneous Camera Pose And Correspondence Estimation With Motion Coherence, Wen-Yan Lin, Loong-Fah Cheong, Ping Tan, Guo Dong, Siying Liu

Research Collection School Of Computing and Information Systems

Traditionally, the camera pose recovery problem has been formulated as one of estimating the optimal camera pose given a set of point correspondences. This critically depends on the accuracy of the point correspondences and would have problems in dealing with ambiguous features such as edge contours and high visual clutter. Joint estimation of camera pose and correspondence attempts to improve performance by explicitly acknowledging the chicken and egg nature of the pose and correspondence problem. However, such joint approaches for the two-view problem are still few and even then, they face problems when scenes contain largely edge cues with few …

A Mems Photoacoustic Detector Of Terahertz Radiation For Chemical Sensing, Nathan Glauvitz, S. Blazevic, Ronald A. Coutu Jr., Michael Kistler, Ivan R. Medvedev, Douglas T. Petkie

Electrical and Computer Engineering Faculty Research and Publications

A piezoelectric Microelectromechanical system (MEMS) cantilever pressure sensor was designed, modeled, fabricated, and tested for sensing the photoacoustic response of gases to terahertz (THz) radiation. The sensing layers were comprised of three thin films; a lead zirconate titanate (PZT) piezoelectric layer sandwiched between two metal contact layers. The sensor materials were deposited on the silicon device layer of a silicon-on-insulator (SOI) wafer, which formed the physical structure of the cantilever. To release the cantilever, a hole was etched through the backside of the wafer and the buried oxide was removed with hydrofluoric acid. Devices were then tested in a custom …

Characterizing Metal-Insulator-Transition (Mit) Phase Change Materials (Pcm) For Rf And Dc Micro-Switching Elements, Brent L. Danner, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Metal-insulator transition (MIT) phase-change materials (PCM) are material compounds that have the ability to be either conductors or insulators depending on external stimuli. A micromachined test structure for applying external electric fields across MIT wire segments was designed and fabricated. Using this novel test structure, Germanium Telluride (GeTe) and Vanadium Oxide (VOx) were successfully transitioned from a conductor to an insulator. The resistivity of the GeTe wire segments increased three to five orders of magnitude with ∼40 V applied to the parallel plates of the test structure. The VOx wires exhibited an order of magnitude transition in resistivity with ∼20 …

Continuous Time-Varying Biasing Approach For Spectrally Tunable Infrared Detectors, Woo-Yong Jang, Majeed M. Hayat, Payman Zarkesh-Ha, Sanjay Krishna

Electrical and Computer Engineering Faculty Research and Publications

In a recently demonstrated algorithmic spectral-tuning technique by Jang et al. [Opt. Express 19, 19454-19472, (2011)], the reconstruction of an object’s emissivity at an arbitrarily specified spectral window of interest in the long-wave infrared region was achieved. The technique relied upon forming a weighted superposition of a series of photocurrents from a quantum dots-in-a-well (DWELL) photodetector operated at discrete static biases that were applied serially. Here, the technique is generalized such that a continuously varying biasing voltage is employed over an extended acquisition time, in place using a series of fixed biases over each sub-acquisition time, which totally …

Multiplication Theory For Dynamically Biased Avalanche Photodiodes: New Limits For Gain Bandwidth Product, Majeed M. Hayat, David A. Ramirez

Electrical and Computer Engineering Faculty Research and Publications

Novel theory is developed for the avalanche multiplication process in avalanche photodiodes (APDs) under time-varying reverse-biasing conditions. Integral equations are derived characterizing the statistics of the multiplication factor and the impulse-response function of APDs, as well as their breakdown probability, all under the assumption that the electric field driving the avalanche process is time varying and spatially nonuniform. Numerical calculations generated by the model predict that by using a bit-synchronous sinusoidal biasing scheme to operate the APD in an optical receiver, the pulse-integrated gain-bandwidth product can be improved by a factor of 5 compared to the same APD operating under …

A Suspended Nanogap Formed By Field-Induced Atomically Sharp Tips, Jun Hyun Han, Kyung Song, Shankar Radhakrishnan, Sang Ho Oh, Chung Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

A sub-nanometer scale suspended gap (nanogap) defined by electric field-induced atomically sharp metallic tips is presented. A strong local electric field (>109 V=m) across micro/nanomachined tips facing each other causes the metal ion migration in the form of dendrite-like growth at the cathode. The nanogap is fully isolated from the substrate eliminating growth mechanisms that involve substrate interactions. The proposed mechanism of ion transportation is verified using real-time imaging of the metal ion transportation using an in situ biasing in transmission electron microscope (TEM). The configuration of the micro/nanomachined suspended tips allows nanostructure growth of a wide variety of …

A New Ensemble Learning Method For Temporal Pattern Identification, Wenjing Zhang, Xin Feng

Electrical and Computer Engineering Faculty Research and Publications

In this paper we present a method for identification of temporal patterns predictive of significant events in a dynamic data system. A new hybrid model using Reconstructed Phase Space (MRPS) and Hidden Markov Model (HMM) is applied to identify temporal patterns. This method constructs phase space embedding by using individual embedding of each variable sequences. We also employ Hidden Markov Models (HMM) to the multivariate sequence data to categorize multi-dimensional data into three states, e.g. normal, patterns and events. A support vector machine optimization method is used to search an optimal classifier to identify temporal patterns that are predictive of …

A Very Robust Algan/Gan Hemt Technology To High Forward Gate Bias And Current, Bradley D. Christiansen, Eric R. Heller, Ronald A. Coutu Jr., Ramakrishna Vetury, Jeffrey B. Shealy

Electrical and Computer Engineering Faculty Research and Publications

Reports to date of GaN HEMTs subjected to forward gate bias stress include varied extents of degradation. We report an extremely robust GaN HEMT technology that survived—contrary to conventional wisdom—high forward gate bias (+6 V) and current (>1.8 A/mm) for >17.5 hours exhibiting only a slight change in gate diode characteristic, little decrease in maximum drain current, with only a 0.1 V positive threshold voltage shift, and, remarkably, a persisting breakdown voltage exceeding 200 V.

Robotic Manufacturing Cell: An Analysis Of Variables Affecting Performance, Elvis Alicic

Dissertations and Theses @ UNI

Analyzing the performance of manufacturing cells is a well established concept. The justification for conducting thorough analyses of manufacturing cells comes from the known advantages it can provide, including performance improvement and production planning improvement, both current and future. This study focuses on assessing the variables affecting performance of a robotic manufacturing cell through the measure of throughput. Initially, simulation modeling is utilized to model an existing robotic cell and compare the output to actual production output from the same cell. Additionally, general regression modeling is employed to analyze the following variables and their effect on throughput: machine downtime, off-plan …

Effects Of Visual Interaction Methods On Simulated Unmanned Aircraft Operator Situational Awareness, Brent A. Terwilliger

Publications

The limited field of view of static egocentric visual displays employed in unmanned aircraft controls introduces the soda straw effect on operators, which significantly affects their ability to capture and maintain situational awareness by not depicting peripheral visual data. The problem with insufficient operator situational awareness is the resulting increased potential for error and oversight during operation of unmanned aircraft, leading to accidents and mishaps costing United States taxpayers between $4 million to $54 million per year. The purpose of this quantitative experimental completely randomized design study was to examine and compare use of dynamic eyepoint to static visual interaction …

Automation Laboratory Development Focusing On Industrial Hands-On Experience, Simulation Software, And Application Research Projects, Cheng Y. Lin, John R. Hackworth

Engineering Technology Faculty Publications

This paper describes the development of an Automation Control Lab in the Department of Engineering Technology at the University. The lab facility includes pneumatic actuators/sensors, electrical relays/switches, and Programmable Logic Controllers (PLC). The major goal of the development is to help students gain hands-on industrial experience by conducting simple projects during the lecture hours and more advanced projects during the lab hours. Simulation software is also applied to reduce implementation time when developing complicated pneumatic circuits and PLC programs. In addition, three examples of industrial automation projects using PLC from the Technology Application Center (TAC) are also introduced to students …

New Perspective On Passively Quenched Single Photon Avalanche Diodes: Effect Of Feedback On Impact Ionization, David A. Ramirez, Majeed M. Hayat, Graham J. Rees, Xudong Jiang, Mark A. Itzler

Electrical and Computer Engineering Faculty Research and Publications

Single-photon avalanche diodes (SPADs) are primary devices in photon counting systems used in quantum cryptography, time resolved spectroscopy and photon counting optical communication. SPADs convert each photo-generated electron hole pair to a measurable current via an avalanche of impact ionizations. In this paper, a stochastically self-regulating avalanche model for passively quenched SPADs is presented. The model predicts, in qualitative agreement with experiments, three important phenomena that traditional models are unable to predict. These are: (1) an oscillatory behavior of the persistent avalanche current; (2) an exponential (memoryless) decay of the probability density function of the stochastic quenching time of the …

Empirical Performance Analysis Of High Performance Computing Benchmarks Across Variations In Cloud Computing, Sindhu Mani

UNF Graduate Theses and Dissertations

High Performance Computing (HPC) applications are data-intensive scientific software requiring significant CPU and data storage capabilities. Researchers have examined the performance of Amazon Elastic Compute Cloud (EC2) environment across several HPC benchmarks; however, an extensive HPC benchmark study and a comparison between Amazon EC2 and Windows Azure (Microsoft’s cloud computing platform), with metrics such as memory bandwidth, Input/Output (I/O) performance, and communication computational performance, are largely absent. The purpose of this study is to perform an exhaustive HPC benchmark comparison on EC2 and Windows Azure platforms.

We implement existing benchmarks to evaluate and analyze performance of two public clouds spanning …

Enhancing Spectrum Utilization In Dynamic Cognitive Radio Systems, Dusadee Treeumnuk

Electrical & Computer Engineering Theses & Dissertations

Cognitive radio (CR) is regarded as a viable solution to enabling flexible use of the frequency spectrum in future generations of wireless systems by allowing unlicensed secondary users (SU) to access licensed spectrum under the specific condition that no harmful interference be caused to the licensed primary users (PU) of the spectrum. In practical scenarios, the knowledge of PU activity is unknown to CRs and radio environments are mostly imperfect due to various issues such as noise uncertainty and multipath fadings. Therefore, important functionalities of CR systems are to efficiently detect availability of radio spectrum as well as to avoid …