Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2017

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 12031 - 12060 of 12521

Full-Text Articles in Physical Sciences and Mathematics

Robust Seed Detection For Coronary Arteries Segmentation Using Thresholded Frangi Response, Sammer Zai, Muhammad Ahsan Ansari, Soon-Young Song, Young Shik Moon Jan 2017

Robust Seed Detection For Coronary Arteries Segmentation Using Thresholded Frangi Response, Sammer Zai, Muhammad Ahsan Ansari, Soon-Young Song, Young Shik Moon

Turkish Journal of Electrical Engineering and Computer Sciences

Automatic detection of initial seed points has become an essential step towards delineating coronary arteries in coronary computed tomography angiography (CCTA) images due to image inhomogeneity and other factors. Most coronary segmentation algorithms require user interaction for seed point selection, which may lead to erroneous segmentation. In this study, we present an improved technique of seed detection for coronary segmentation using a thresholded Frangi response. Before computing region of interest (ROI), the proposed method first computes the Frangi response of the complete CCTA volume, followed by thresholding with respect to quantile and median values, and then the ROI selection procedure …

Go to article

A Secure Cross-Layer Aodv Routing Method To Detect And Isolate (Sclardi) Black Hole Attacks For Manet, Usha Gopal, Kannimuthu Subramanian Jan 2017

A Secure Cross-Layer Aodv Routing Method To Detect And Isolate (Sclardi) Black Hole Attacks For Manet, Usha Gopal, Kannimuthu Subramanian

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a secure cross-layer--based routing technique (SCLARDI) for a mobile ad hoc network (MANET) is proposed. This technique makes use of ad hoc on-demand routing protocol (AODV) algorithms and honeypot technology to detect and isolate black hole attacks from MANETs. This novel system is compared with the single-layer design techniques and existing cross-layer detection techniques. Out of the tested models, the proposed cross-layer design is the most suitable for MANET security. First, the vulnerabilities of the AODV routing protocol against black hole attacks are analyzed. Second, a secure cross-layer--based AODV routing technique is proposed. The proposed SCLARDI technique …

Go to article

Adaptive Decision Fusion Based Framework For Short-Term Wind Speed And Turbulence Intensity Forecasting: Case Study For North West Of Turkey, Çi̇ğdem Di̇nçkal, Behçet Uğur Töreyi̇n, Serhat Küçükali̇ Jan 2017

Adaptive Decision Fusion Based Framework For Short-Term Wind Speed And Turbulence Intensity Forecasting: Case Study For North West Of Turkey, Çi̇ğdem Di̇nçkal, Behçet Uğur Töreyi̇n, Serhat Küçükali̇

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an online learning framework called adaptive decision fusion (ADF) is employed for short-term wind speed and turbulence intensity forecasting by use of wind speed data for each season for the city of İzmit, located in the northwest of Turkey. Fixed-weight (FW) linear combination is derived and used for comparison with ADF. Wind speeds and turbulence intensities are predicted from the existing wind speed data and computed turbulence intensities, respectively, using the ADF and FW methods. Simulations are carried out for each season and the results are tested on mean absolute percentage error criterion. It is shown that …

Go to article

Evaluation Of Distance Education Websites: A Hybrid Multicriteria Approach, Mehmet Kabak, Eren Özceylan, Meti̇n Dağdevi̇ren, Tolga Genç Jan 2017

Evaluation Of Distance Education Websites: A Hybrid Multicriteria Approach, Mehmet Kabak, Eren Özceylan, Meti̇n Dağdevi̇ren, Tolga Genç

Turkish Journal of Electrical Engineering and Computer Sciences

This study provides an evaluation model that prioritizes the relative weights of various distance education websites. The proposed approach consists of four sequential steps. In the first step, 25 different subcriteria under 4 major criteria are gathered from the existing literature. Identified criteria are weighted by stakeholders of distance education websites using the analytic network process outlined in the second step. In the third step, the technique for order preference by similarity to ideal solution method is applied in order to rank the 15 different Turkish distance education website alternatives. Finally, in the fourth step, different scenario analyses are applied …

Go to article

Extraction Of Geometric And Prosodic Features From Human-Gait-Speech Data For Behavioral Pattern Detection: Part I, Raj Kumar Patra, Tilendra Shishir Sinha, Ravi Prakash Dubey Jan 2017

Extraction Of Geometric And Prosodic Features From Human-Gait-Speech Data For Behavioral Pattern Detection: Part I, Raj Kumar Patra, Tilendra Shishir Sinha, Ravi Prakash Dubey

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, we extract prosodic features from subjects while they are talking while walking using human-gait-speech data. These human-gait-speech data are separated into 1D data (human-speech) and 2D data (human-gait) using the adaptive-lifting scheme of wavelet transform. We carry out extraction of prosodic features from human-speech data, such as speech duration, pitch, speaking rate, and speech momentum, using five different natural languages (Hindi, Bengali, Oriya, Chhattisgarhi, and English) for the detection of behavioral patterns. These behavioral patterns form real-valued measured parameters, stored in a knowledge-based model called the human-gait-speech model. Extraction of geometrical features from human-gait data, such as …

Go to article

Development Of Pmu-Based Backup Wide Area Protection For Power Systems Considering Hif Detection, Saeed Asgharigoavr, Heresh Seyedi Jan 2017

Development Of Pmu-Based Backup Wide Area Protection For Power Systems Considering Hif Detection, Saeed Asgharigoavr, Heresh Seyedi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a wavelet packet transform (WPT)-based algorithm is proposed to develop and improve the backup wide area protection for power systems equipped with phasor measurement units (PMUs). Faults on power systems such as high impedance faults (HIFs) have specific characteristics that include high frequency components that can be extracted using the WPT, which is one of the important methods in signal processing. The proposed idea uses power system voltage and current, measured by voltage and current transformers, respectively, and calculates high frequency information of voltage and current waveforms. Afterwards, the differences of voltage coefficients of each phase at …

Go to article

Visualization Of Distribution System Planning For Engineers And Decision-Makers, Tomislav Capuder, Hrvoje Pandzic, Igor Kuzle Jan 2017

Visualization Of Distribution System Planning For Engineers And Decision-Makers, Tomislav Capuder, Hrvoje Pandzic, Igor Kuzle

Turkish Journal of Electrical Engineering and Computer Sciences

Planning of an electric distribution network is a complex task, requiring a comprehensive approach that includes collecting and analyzing large amounts of technical and nontechnical data. In addition, the outcome of the planning procedure needs to be supported by economic analysis that provides pathways for future investments. In order to present the planning results to various groups of people, such as technical staff, managers, and politicians, different visualization techniques are used. Data visualization, as a branch of descriptive statistics, is important to understand and present information in an effective manner. The basic idea of visualization is to present data in …

Go to article

Analysis Of A Joined Split-Ring Fss Structure Characterized By Three Resonant Frequencies And A Tuned Enhanced Band Using The Wcip Method, Manel Aouissi, Mohammed Titaouine, Thayuan Rolim De Sousa, Ibtissem Adoui, Alfredo Gomes Neto, Henri Baudrand Jan 2017

Analysis Of A Joined Split-Ring Fss Structure Characterized By Three Resonant Frequencies And A Tuned Enhanced Band Using The Wcip Method, Manel Aouissi, Mohammed Titaouine, Thayuan Rolim De Sousa, Ibtissem Adoui, Alfredo Gomes Neto, Henri Baudrand

Turkish Journal of Electrical Engineering and Computer Sciences

This work presents the analysis of a joined split-ring frequency selective surface (FSS) for X-band applications using the wave concept iterative procedure (WCIP). When the incident normal plane wave is polarized in the $x$ direction, the joined split-ring FSS shows three rejecting bands at 9 GHz, 10.5 GHz, and 11.5 GHz simultaneously with bandwidths of 3.11 GHz, 0.6 GHz, and 1.13 GHz, respectively. Moreover, one rejecting band at 6.5 GHz is present when the FSS is fed with a normal plane excited in the $y$ direction. In addition, the different resonant frequencies can be tuned independently to give rise to …

Go to article

A Spectral Element Method For The Solution Of Magnetostatic Fields, Ibrahim Mahariq, Atakan Erciyas Jan 2017

A Spectral Element Method For The Solution Of Magnetostatic Fields, Ibrahim Mahariq, Atakan Erciyas

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, we have seen good progress in our capability to simulate complex electromagnetic systems. However, still there exist many challenges that have to be tackled in order to push limits restricting the field of computational electromagnetics upward. One of these challenges is the limitations in the available computational resources. Over several decades, the traditional computational methods, such as finite difference, finite element, and finite volume methods, have been extensively applied in the field of electromagnetics. On the other hand, the spectral element method (SEM) has been recently utilized in some branches of electromagnetics as waveguides and photonic structures for the …

Go to article

Token-Based Authentication Method For M2m Platforms, Hüseyi̇n Polat, Saadi̇n Oyucu Jan 2017

Token-Based Authentication Method For M2m Platforms, Hüseyi̇n Polat, Saadi̇n Oyucu

Turkish Journal of Electrical Engineering and Computer Sciences

Nowadays the fields in which machine-to-machine (M2M) applications are used and the numbers of M2M devices and users are increasing gradually. In an M2M application, M2M platforms are used in order to follow and analyze the data presented by M2M devices. The communication of multiple users and devices via an M2M platform causes some problems in terms of security. In this study, an M2M platform has been developed by using RestFul web services and NoSQL database. On this platform a token-based authentication method was used for multiple users and devices. In this method, an authorized request approach was adopted for …

Go to article

Two-Group Decodable Distributed Differential Space-Time Code For Wireless Relay Networks Based On Sast Codes, Obada Abdallah, Ammar Abu Hudrouss Jan 2017

Two-Group Decodable Distributed Differential Space-Time Code For Wireless Relay Networks Based On Sast Codes, Obada Abdallah, Ammar Abu Hudrouss

Turkish Journal of Electrical Engineering and Computer Sciences

Space-time code can be implemented in wireless relay networks when all relays cooperate to generate the code at the receiver. In this case, it is called distributed space-time code. If the channel response changes very quickly, the idea of differential space-time coding is needed to overcome the difficulty of updating the channel state information at the receiver. As a result, the transmitted signal can be demodulated without any knowledge of the channel state information at the relays or the receiver. In this paper, development of new low decoding complexity distributed differential space-time codes is considered. The developed codes are designed …

Go to article

An Ultralow Power, 0.003-Mm$^{2}$ Area, Voltage To Frequency-Based Smart Temperature Sensor For -55 $^{\Circ}$C To +125 $^{\Circ}$C With One-Point Calibration, Mudasir Bashir, Sreehari Rao Patri, Krishnaprasad Ksr Jan 2017

An Ultralow Power, 0.003-Mm$^{2}$ Area, Voltage To Frequency-Based Smart Temperature Sensor For -55 $^{\Circ}$C To +125 $^{\Circ}$C With One-Point Calibration, Mudasir Bashir, Sreehari Rao Patri, Krishnaprasad Ksr

Turkish Journal of Electrical Engineering and Computer Sciences

With the scaling of transistor feature size and increased integration density, power density has increased, resulting in high chip temperature, thus degrading the performance and lifetime of the chip. In this work, an ultralow power smart temperature sensor employing a frequency locked loop technique is developed in 65 nm standard CMOS process. The circuit works on the principle of voltage to frequency conversion, exploiting the thermal dependency of threshold voltage (V$_{th})$ of MOS transistors in the subthreshold region. The sensor along with signal conditioning subcircuits has a low power consumption of 1.92 $\mu $W, while operating over -55 $^{\circ}$C to …

Go to article

Mopso-Based Predictive Control Strategy For Efficient Operation Of Sensorless Vector-Controlled Fuel Cell Electric Vehicle Induction Motor Drives, Adel Abdelaziz Abdelghany Elgammal, Mohammed Fathy El_Naggar Jan 2017

Mopso-Based Predictive Control Strategy For Efficient Operation Of Sensorless Vector-Controlled Fuel Cell Electric Vehicle Induction Motor Drives, Adel Abdelaziz Abdelghany Elgammal, Mohammed Fathy El_Naggar

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces an optimal control strategy of model-based predictive control (MPC) based on multiobjective particle swarm optimization (MOPSO) for a sensorless vector control induction motor, which is used in a fuel cell electric vehicle drive system. The proposed MPC-MOPSO algorithm is implemented to tune the weighting parameters of the MPC controller to tackle all the conflicting objective functions. The paper handles the following fitness functions: minimizing the speed error, minimizing the torque ripple, minimizing the DC-link voltage ripple, and minimizing machine flux ripple. Computer simulations studies have been completed utilizing MATLAB/Simulink with a specific end goal of assessing the …

Go to article

Analytical Modeling Of A Coaxial Cylindrical Probe Capacitive Sensor Based On Matlab/Simulink For Conductive Liquids Level Measurements, Majid Toghyani Rizi, Mohammad Hadi Shahrokh Abadi Jan 2017

Analytical Modeling Of A Coaxial Cylindrical Probe Capacitive Sensor Based On Matlab/Simulink For Conductive Liquids Level Measurements, Majid Toghyani Rizi, Mohammad Hadi Shahrokh Abadi

Turkish Journal of Electrical Engineering and Computer Sciences

Measurement of liquid level is an important process variable in the operation of many process industries such as water treatment plants. There are different types of level sensors to measure this parameter, categorized into ultrasonic, capacitive, optical, microwave, magnetostrictive, resistive chain, magnetoresistive, hydrostatic pressure, air bubbler, gamma ray, etc. In this paper, a cylindrical probe capacitive sensor for measuring the level of conductive liquids has been modeled based on a step-by-step mathematical procedure, using MATLAB/Simulink. The steps take the relation between the different capacitances in the model with the height of the conductive liquid into account. The results show a …

Go to article

Energy And Area Spectral Efficiency Trade-Off For Mc-Cdma With Carrier Frequency Offset, Junaid Ahmed, Moazzam Islam Tiwana, Omer Ahmed, Sarmad Sohaib Jan 2017

Energy And Area Spectral Efficiency Trade-Off For Mc-Cdma With Carrier Frequency Offset, Junaid Ahmed, Moazzam Islam Tiwana, Omer Ahmed, Sarmad Sohaib

Turkish Journal of Electrical Engineering and Computer Sciences

Intercell interference is a major factor that limits the capacity of cellular wireless communication systems. This paper proposes an accurate statistical model that caters to interference and noise to determine the ergodic capacity. A new expression for ergodic capacity is derived that enables us to calculate area spectral efficiency (ASE) and energy efficiency (EE). This expression has been used to calculate and compare ASE and EE for low and high traffic scenarios with various signal-to-noise ratios and intercell distances.

Go to article

Energy Optimized Scheduling For Non-Preemptive Real-Time Systems, Vasanthamani Kannaian, Visalakshi Palanisamy Jan 2017

Energy Optimized Scheduling For Non-Preemptive Real-Time Systems, Vasanthamani Kannaian, Visalakshi Palanisamy

Turkish Journal of Electrical Engineering and Computer Sciences

Embedded systems have geared up their applications in the field of smart phones, mobile devices, automobiles, and medical instrumentation. Along with the growth of technology, the functional requirements of the systems have also grown multifold. To accommodate these ever increasing functional requirements, the hardware should be designed to include the maximum capability, which in turn increases power consumption. Thus this has to be dynamically managed using software techniques. The dynamic voltage and frequency scaling (DVFS) feature provided in most of the recent processors has enabled power optimization through software. With this feature the processor operating frequency can be reduced on …

Go to article

A New Sequential Power Flow Algorithm For Ac/Dc Systems Including Independent Multiterminal Dc Subsystems, Faruk Yalçin, Uğur Ari̇foğlu Jan 2017

A New Sequential Power Flow Algorithm For Ac/Dc Systems Including Independent Multiterminal Dc Subsystems, Faruk Yalçin, Uğur Ari̇foğlu

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new algorithm based on the sequential method for power flow calculation in multiterminal AC/DC systems. The proposed approach differs from other similar studies in the literature by handling two main properties. Firstly, a real equivalent circuit model is considered for the under-load tap changer transformers (ULTCs) of DC converters for the first time in the literature. Hence, new DC equations are obtained. Thus, exact and accurate results can be obtained for practical applications using the proposed algorithm. Tap values adjustment effects of the ULTCs connected to DC converters are included into the Jacobian matrix instead of …

Go to article

An Intelligent Pso-Based Energy Efficient Load Balancing Multipath Technique In Wireless Sensor Networks, Sukhchandan Randhawa, Sushma Jain Jan 2017

An Intelligent Pso-Based Energy Efficient Load Balancing Multipath Technique In Wireless Sensor Networks, Sukhchandan Randhawa, Sushma Jain

Turkish Journal of Electrical Engineering and Computer Sciences

To provide a reliable and efficient service, load balancing plays an important role in wireless sensor networks (WSNs). There is a need to maximize the network lifetime for WSNs applications with periodic generation of data. Due to the relationship between energy consumption and network sensor node lifetime, energy consumption in a network should be minimized and balanced in order to increase network lifetime. Energy-efficient load-balancing techniques are needed to solve this problem. In this paper, a particle swarm optimization (PSO)-based energy-efficient load-balancing technique is proposed, in which the required number of routing paths and energy consumption of different nodes and …

Go to article

Minimizing Reverse Current Flow Due To Distributed Generation Via Optimal Network Reconfiguration, Jasrul Jamani Jamian, Muhammad Mohsin Aman, Muhammad Ariff Baharuddin, Ahmad Safawi Mokhtar, Mohd Noor Abdullah Jan 2017

Minimizing Reverse Current Flow Due To Distributed Generation Via Optimal Network Reconfiguration, Jasrul Jamani Jamian, Muhammad Mohsin Aman, Muhammad Ariff Baharuddin, Ahmad Safawi Mokhtar, Mohd Noor Abdullah

Turkish Journal of Electrical Engineering and Computer Sciences

Distributed generation (DG) is widely used to minimize total power losses in distribution networks. However, one of the problems of DG in a grid system is reverse current flow (RCF), which is when the DG output becomes greater than the connected load. Therefore, this paper proposes a multiobjective artificial bee colony (MOABC) algorithm to determine the optimal network reconfiguration for reducing total RCF in DG. The proposed algorithm is tested on 33-bus radial distribution systems in two different scenarios, i.e. base case and with 50% load. The proposed technique can reduce reverse current by up to 93%; however, the total …

Go to article

Robust Local Parameter Estimator Based On Least Absolute Value Estimator, Volkan Özdemi̇r, Murat Göl Jan 2017

Robust Local Parameter Estimator Based On Least Absolute Value Estimator, Volkan Özdemi̇r, Murat Göl

Turkish Journal of Electrical Engineering and Computer Sciences

Changes in weather conditions such as temperature and humidity, miscommunication between the control center and circuit breaker transducers and tap changers, and inaccurate manufacturing data may cause parameter errors. Because of incorrect parameters, the state estimator may provide biased state estimates, which may lead to many serious economic and operational results. In order to prevent that, one must identify and correct those parameter errors. This work proposes a local parameter estimator based on the least absolute value (LAV) estimator, which is known to be robust against bad measurements, i.e. measurements with gross error. Considering the increasing number of phasor measurement …

Go to article

Tsgv: A Table-Like Structure-Based Greedy Method For Materialized View Selection In Data Warehouses, Mohammad Karim Sohrabi, Hossein Azgomi Jan 2017

Tsgv: A Table-Like Structure-Based Greedy Method For Materialized View Selection In Data Warehouses, Mohammad Karim Sohrabi, Hossein Azgomi

Turkish Journal of Electrical Engineering and Computer Sciences

Since a data warehouse deals with huge amounts of data and complex analytical queries, online processing and answering to users' queries in data warehouses can be a serious challenge. Materialized views are used to speed up query processing rather than direct access to the database in on-line analytical processing. Since the large number and high volume of views prevents all of the views from being stored, selection of a proper subset of views to materialization is inevitable. Proposing an appropriate method for selecting the optimal subset of views for materialization plays an essential role in increasing the efficiency of responding …

Go to article

Dynamic Security Enhancement Of Power Systems Using Mean-Variance Mapping Optimization, Cavi̇t Fati̇h Küçüktezcan, Veysel Murat İstemi̇han Genç Jan 2017

Dynamic Security Enhancement Of Power Systems Using Mean-Variance Mapping Optimization, Cavi̇t Fati̇h Küçüktezcan, Veysel Murat İstemi̇han Genç

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a preventive control action that involves both generation rescheduling and load curtailment is proposed for enhancing the dynamic security of large interconnected power systems. The control action is formulated as a security-constrained optimization problem that is solved by mean-variance mapping optimization (MVMO) integrated with a self-adaptive penalization technique and artificial neural networks to develop a fast and effective methodology. The proposed methodology is applied to a 16-generator 68-bus test system to solve the security-constrained optimization problem with both continuous and discrete decision variables. To find a proper and cost-effective solution for the control actions within an acceptable …

Go to article

Assessment Of Disordered Voices Based On An Optimized Glottal Source Model, Mounir Boudjerda, Abdellah Kacha Jan 2017

Assessment Of Disordered Voices Based On An Optimized Glottal Source Model, Mounir Boudjerda, Abdellah Kacha

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a method for the assessment of disordered voices is proposed. A feature named mean opening quotient (MOQ) obtained from the glottal source estimation is used as an acoustic cue to summarize the degree of severity of the voice disorder. The analysis method uses the empirical mode decomposition algorithm to estimate the glottal source excitation signal from the speech signal. The logarithm of the magnitude spectrum of the speech signal is decomposed into oscillatory modes, called intrinsic mode functions, that are clustered into two classes, the spectral envelope and the harmonic component. The exploitation of the phase information …

Go to article

Distinct Degradation Processes In Zno Varistors: Reliability Analysis And Modeling With Accelerated Ac Tests, Hadi Yadavari, Mustafa Altun Jan 2017

Distinct Degradation Processes In Zno Varistors: Reliability Analysis And Modeling With Accelerated Ac Tests, Hadi Yadavari, Mustafa Altun

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, we investigate different degradation mechanisms of zinc oxide (ZnO) varistors. We propose a model that shows how Vv (defined as DC varistor voltage when a 1-mA DC current is applied) changes with time for different stress levels. For this purpose, accelerated degradation tests are applied for different AC current levels and voltage values are then measured. Different from the common practice in the literature that considers degradation with only decreasing Vv values, we demonstrate either an increasing or a decreasing trend in the Vv parameter. The tests show a decreasing trend in Vv for current levels above …

Go to article

Unsupervised Learning Of Allomorphs In Turkish, Burcu Can Jan 2017

Unsupervised Learning Of Allomorphs In Turkish, Burcu Can

Turkish Journal of Electrical Engineering and Computer Sciences

One morpheme may have several surface forms that correspond to allomorphs. In English, ed and $d$ are surface forms of the past tense morpheme, and $s$, es, and ies are surface forms of the plural or present tense morpheme. Turkish has a large number of allomorphs due to its morphophonemic processes. One morpheme can have tens of different surface forms in Turkish. This leads to a sparsity problem in natural language processing tasks in Turkish. Detection of allomorphs has not been studied much because of its difficulty. For example, tü and di are Turkish allomorphs (i.e. past tense morpheme), but …

Go to article

Instantaneous Protection Scheme For Backup Protection Of High-Voltage Transmission Lines, Syed Norazizul Syed Nasir, Abdullah Asuhaimi Jan 2017

Instantaneous Protection Scheme For Backup Protection Of High-Voltage Transmission Lines, Syed Norazizul Syed Nasir, Abdullah Asuhaimi

Turkish Journal of Electrical Engineering and Computer Sciences

The protection scheme focused on in this study is a typical protection system used in high-voltage systems such as 132 kV, 275 kV, and 500 kV. The research will analyze the existing protection scheme for transmission lines that the power utility has implemented and will propose a new protection scheme to improve the performance of the existing scheme. The existing protection scheme currently implemented by the power utility for backup protection operation has a longer fault-clearing time and no restoration time, and it does not utilize support relays. This study will focus on a backup protection operation on high-voltage overhead …

Go to article

A Particle Swarm Optimization And Block-Svd-Based Watermarking For Digital Images, Falgun Thakkar, Vinay Kumar Srivastava Jan 2017

A Particle Swarm Optimization And Block-Svd-Based Watermarking For Digital Images, Falgun Thakkar, Vinay Kumar Srivastava

Turkish Journal of Electrical Engineering and Computer Sciences

The major issues in most watermarking schemes are security, reliability, and robustness against attacks. To achieve these objectives in a watermarking algorithm, the selection of a scale factor to embed the watermark into the host image is a challenging problem. In this paper, a block singular value decomposition (SVD)-based reliable, robust, secure, and fast watermarking scheme is proposed that uses particle swarm optimization (PSO) in the selection of the scale factor. SVD is applied here on the nonoverlapping blocks of LL wavelet subbands. Selected singular values of these blocks are modified with the pixel values of the watermark image. Selected …

Go to article

High-Voltage Isolated Multioutput Power Supply For Multilevel Converters, Amir Sepehr, Mehdi Saradarzadeh, Shahrokh Farhangi Jan 2017

High-Voltage Isolated Multioutput Power Supply For Multilevel Converters, Amir Sepehr, Mehdi Saradarzadeh, Shahrokh Farhangi

Turkish Journal of Electrical Engineering and Computer Sciences

Multilevel converters are one of the major choices for realizing high electric power conversion. The major feature of multilevel converter topologies is the need for a large number of switches, each of which requires a gate driver circuit and an isolated DC power supply. In this paper, a pragmatic concept of design and implementation of an isolated DC-to-DC converter for a high-voltage isolated application is introduced. More specifically, a multiple isolated output power supply based on the benefits of resonant converters is designed to prepare 36 double DC voltages for driving power semiconductor devices in a three-phase, seven-level cascaded H-bridge …

Go to article

An Alternative Approach To The Design Of Multiple Beam Constrained Lens Antennas, Rasi̇me Uyguroğlu, Abdullah Yücel Öztoprak Jan 2017

An Alternative Approach To The Design Of Multiple Beam Constrained Lens Antennas, Rasi̇me Uyguroğlu, Abdullah Yücel Öztoprak

Turkish Journal of Electrical Engineering and Computer Sciences

Rotman lenses are constrained lenses that are used as beam-forming networks to feed array antennas. Their design is based on three focal points, producing three beams with perfect phase fronts. This paper introduces an alternative constrained lens, which has phase equality at five radiating array elements for each beam position. In addition, the center point of the feed curve produces a perfect beam at broadside. The performance of this lens is analyzed and compared to the conventional Rotman lens. The analysis demonstrates that the new lens has better phase performance for wide angle designs. Our study shows that the phase …

Go to article

Access Pattern-Aware Data Placement For Hybrid Dram/Nvm, Di̇dem Unat Erten Jan 2017

Access Pattern-Aware Data Placement For Hybrid Dram/Nvm, Di̇dem Unat Erten

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, increased interest in data-centric applications has led to an increasing demand for large-capacity memory systems. Nonvolatile memory (NVM) technologies enable new opportunities in terms of process-scaling and energy consumption, and have become an attractive memory technology that serves as a secondary memory at low cost. However, NVM has certain disadvantages for write references, due to its high dynamic energy consumption for writes and low bandwidth compared to DRAM writes. In this paper, we propose an access-aware placement of objects in the application code for two types of memories. Given the desired power savings and acceptable performance loss, …

Go to article

First Prev Next Last