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Articles 14251 - 14280 of 25622

Full-Text Articles in Computer Engineering

Analysis And Design Of An Invisibility Cloak Based On Transformation Optics At Microwave Frequencies, Maryam Bayati, Masood Omoomi Jan 2017

Analysis And Design Of An Invisibility Cloak Based On Transformation Optics At Microwave Frequencies, Maryam Bayati, Masood Omoomi

Turkish Journal of Electrical Engineering and Computer Sciences

Invisibility cloaks can be constructed with electromagnetic metamaterials. In this paper, structural metamaterials are used to design an invisibility cloak. To this end, transformation optics is used to design electromagnetic parameters. These parameters are selected so that when we excite the cloak its presence does not perturb radiated fields. Therefore, we formulate the electric field both at the inner and outer parts of the cloak, when the excitation source is placed both inside and outside, and we show that the scattered fields will be suppressed due to its presence. Finally, simulation results verify that the invisibility cloak is well designed …

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An Adaptive Clustering Segmentation Algorithm Based On Fcm, Jun Yang, Yun-Sheng Ke, Mao-Zheng Wang Jan 2017

An Adaptive Clustering Segmentation Algorithm Based On Fcm, Jun Yang, Yun-Sheng Ke, Mao-Zheng Wang

Turkish Journal of Electrical Engineering and Computer Sciences

The cluster number and the initial clustering centers must be reasonably set before the analysis of clustering in most cases. Traditional clustering segmentation algorithms have many shortcomings, such as high reliance on the specially established initial clustering center, tendency to fall into the local maximum point, and poor performance with multithreshold values. To overcome these defects, an adaptive fuzzy C-means segmentation algorithm based on a histogram (AFCMH), which synthesizes both main peaks of the histogram and optimized Otsu criterion, is proposed. First, the main peaks of the histogram are chosen by operations like histogram smoothing, merging of adjacent peaks, and …

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A New Video Forgery Detection Approach Based On Forgery Line, Işilay Bozkurt, Mustafa Hakan Bozkurt, Güzi̇n Ulutaş Jan 2017

A New Video Forgery Detection Approach Based On Forgery Line, Işilay Bozkurt, Mustafa Hakan Bozkurt, Güzi̇n Ulutaş

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, we have continually encountered multimedia files in daily life, as evidence in courts, medical records in hospitals, etc. Many multimedia-editing software tools have been developed in parallel to the widespread usage of multimedia files. Thus, forgery operations can be committed by anyone with this software, even if s/he does not have any skill in this field. Authentication of the originality of multimedia files has recently become a popular topic. In this work, we propose a new video forgery detection approach to detect forged frames with better execution and detection capability. Features are extracted from the frames and …

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Breast-Region Segmentation In Mri Using Chest Region Atlas And Svm, Aida Fooladivanda, Shahriar Baradaran Shokouhi, Nasrin Ahmadinejad Jan 2017

Breast-Region Segmentation In Mri Using Chest Region Atlas And Svm, Aida Fooladivanda, Shahriar Baradaran Shokouhi, Nasrin Ahmadinejad

Turkish Journal of Electrical Engineering and Computer Sciences

An important step for computerized analysis of breast magnetic resonance imaging (MRI) is segmentation of the breast region. Due to the similar signal intensity of fibroglandular tissue and the chest wall, the segmentation process is difficult for breasts with fibroglandular tissue connected to the chest wall. In order to overcome this challenge, a new framework is presented that relies on a chest region atlas. The proposed method first detects the approximated breast-chest wall boundary using an intensity-based operation. A support vector machine (SVM) then determines the connectivity of fibroglandular tissue to the chest wall by the extracted features from the …

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Two-Bit Transform Using Local Binary Pattern Method For Low-Complexity Block Motion Estimation, Aysun Taşyapi Çelebi̇ Jan 2017

Two-Bit Transform Using Local Binary Pattern Method For Low-Complexity Block Motion Estimation, Aysun Taşyapi Çelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Low bit-depth representation-based motion estimation approaches have been drawing considerable attention recently, mainly because of their small hardware footprint. In this paper, a new two-bit transform using a local binary pattern (LBP) for low-complexity motion estimation is proposed. The proposed approach utilizes the LBP method to obtain two-bit representations of video frames in the binarization process. Video frames are transformed into their low bit-depth representations by the LBP and then a motion estimation process is carried out using these binary frames. A Boolean exclusive-OR operation is used to calculate the number of nonmatching points metric instead of the conventional sum …

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Lifetime Maximization Of Wireless Sensor Networks With Sink Costs, Muhammed Emre Keski̇n Jan 2017

Lifetime Maximization Of Wireless Sensor Networks With Sink Costs, Muhammed Emre Keski̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Balanced distribution of the energy load of the sensors is important for the elongation of wireless sensor network (WSN) lifetimes. There are four main WSN design issues affecting the energy distribution among the sensors: sensor locations, sensor activity schedules, mobile sink routes, and data flow routes. Many studies try to make energy usage more efficient through optimal determination of these design issues. However, only very few studies handle these four design issues in a combined manner. Additionally, the cost of the sinks is neglected in all studies. In this study, a mixed integer linear program is first proposed, in which …

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Reactive Power Optimization In A Power System Network Through Metaheuristic Algorithms, Chandragupta Mauryan Kuppamuthu Sivalingam, Subramanian Ramachandran, Purrnimaa Shiva Sakthi Rajamani Jan 2017

Reactive Power Optimization In A Power System Network Through Metaheuristic Algorithms, Chandragupta Mauryan Kuppamuthu Sivalingam, Subramanian Ramachandran, Purrnimaa Shiva Sakthi Rajamani

Turkish Journal of Electrical Engineering and Computer Sciences

Reactive power optimization (RPO) in a power system is a rudimentary necessity for the reduction of the loss of power. For the requirement of a unity power factor in the RPO system, the reduction of the system losses is ensured. The pivotal requirements of a power system are inclusive of a perfect compensation technique and methodology for stable reactive power compensation. The proposed concept in this paper utilizes the different reactive power optimization algorithms and performs a comparison. The process is accomplished by the use of IEEE 6-bus, 14-bus, and 30-bus systems to test the optimization technique. The conclusive information …

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A Modified Two-Degree Of Freedom-Internal Model Control Configuration For Load Frequency Control Of A Single Area Power System, Bheem Sonker, Deepak Kumar, Paulson Samuel Jan 2017

A Modified Two-Degree Of Freedom-Internal Model Control Configuration For Load Frequency Control Of A Single Area Power System, Bheem Sonker, Deepak Kumar, Paulson Samuel

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we propose a modified two degree-of-freedom internal model control structure, with dual feedback loop configuration for the load frequency control problem of a single-area power system. Our main objective is to achieve better transient and steady state performance. The predictive model of the proposed configuration is derived through the stability equation method, which preserves the stability of the model. The proposed scheme is simulated for a single-area power system with nonreheated turbine and 50% parametric uncertainty. It is observed from the responses and the performance indices that the proposed control configuration gives better results compared to well-known …

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Power Search Algorithm (Psa) For Combined Economic-Emission Dispatch Problems Considering Valve Point Effects In Economic Load Dispatch, Prakash Arumugam, Ravichandran Coimbatore Subramanian Jan 2017

Power Search Algorithm (Psa) For Combined Economic-Emission Dispatch Problems Considering Valve Point Effects In Economic Load Dispatch, Prakash Arumugam, Ravichandran Coimbatore Subramanian

Turkish Journal of Electrical Engineering and Computer Sciences

Economic load dispatch has become the prime and major concern in power system networks. Use of nonrenewable fuels as an input to power systems results in toxic gas emission and depletion of resources for future generations. Allocation of optimal power to generators serves as a solution to this issue. The suggested power search algorithm (PSA) is a novel solution for the reduction of the fuel cost, emissions, and power loss. This algorithm searches its solution inside the search space from minimum to maximum in case of forward search. The global optimum solution is obtained with much less execution time compared …

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Markovian Model For Reliability Assessment Of Microgrids Considering Load Transfer Restriction, Mohammad Almuhaini, Abdulrahman Al-Sakkaf Jan 2017

Markovian Model For Reliability Assessment Of Microgrids Considering Load Transfer Restriction, Mohammad Almuhaini, Abdulrahman Al-Sakkaf

Turkish Journal of Electrical Engineering and Computer Sciences

Reliability is an indispensable factor in power system design and operation and has a significant impact on grid safety and economy. Future power distribution systems are expected to be more sophisticated, owing to the increasing penetration of renewable resources and adoption of advanced information and communication technologies. Extant studies in this field tend to focus on the modeling and assessment of the reliability of future microgrid distribution systems, including distributed generation, without considering networked configuration and limited transfer capacity. In the work presented in this paper, a Markov model is implemented to perform a practical and accurate reliability evaluation of …

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Optimal Reactive Power Flow In Bdfms For Converter Cost Reduction And Efficiency Improvement, Behzad Jandaghi, Hamed Gorginpour, Mohammad Naser Hashemnia, Hashem Oraee Jan 2017

Optimal Reactive Power Flow In Bdfms For Converter Cost Reduction And Efficiency Improvement, Behzad Jandaghi, Hamed Gorginpour, Mohammad Naser Hashemnia, Hashem Oraee

Turkish Journal of Electrical Engineering and Computer Sciences

A brushless doubly fed machine is equipped with two decoupled windings on its stator, known as the power winding and the control winding. The power winding reactive power can be controlled by voltage amplitude fed by the machine-side converter to the control winding, affecting both the converter size and machine efficiency. This paper investigates different proposed scenarios for optimal reactive power flow targeted to minimize the converter cost and maximize the machine efficiency. Previously, the grid-side converter has not been used for reactive power compensation. However, in the present paper it is shown how the grid-side converter can be effectively …

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Design Optimization Of Distribution Transformers With Nature-Inspired Metaheuristics: A Comparative Analysis, Levent Alhan, Nejat Yumuşak Jan 2017

Design Optimization Of Distribution Transformers With Nature-Inspired Metaheuristics: A Comparative Analysis, Levent Alhan, Nejat Yumuşak

Turkish Journal of Electrical Engineering and Computer Sciences

Many economies in the world have adopted energy-efficiency requirements or incentive programs mandating or promoting the use of energy-efficient transformers. On the other hand, increases in transformer efficiency are subject to increases in transformer weight and size, sometimes as much as 50% or more. The transformer manufacturing industry is therefore faced with the challenge to develop truly optimum designs. Transformer design optimization (TDO) is a mixed-integer nonlinear programming problem having a complex and discontinuous objective function and constraints, with the objective of detailed calculation of the characteristics of a transformer based on national and/or international standards and transformer user requirements, …

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Calculation Of Current Limiting Reactance Of Hybrid Sfcl For Low Voltage Ride-Through Capability Enhancement In Dfig Wind Farms, Sillawat Romphochai, Komsan Hongesombut Jan 2017

Calculation Of Current Limiting Reactance Of Hybrid Sfcl For Low Voltage Ride-Through Capability Enhancement In Dfig Wind Farms, Sillawat Romphochai, Komsan Hongesombut

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new approach for the low voltage ride-through capability enhancement of doubly-fed induction generator (DFIG) wind farms using a hybrid superconducting fault current limiter (SFCL) of the first peak current limiting type, which has the advantage of a fast recovery time. A design for the hybrid SFCL, focusing on current limiting reactor (CLR) reactance calculation, is proposed in this paper to determine an appropriate value for the CLR reactance that satisfies the grid code requirements of the DFIG wind turbines. High-temperature superconductors (HTS) such as Bi-2212, YBCO, Bi-2223, Ti-2223, and Hg-1223 are investigated for use in the …

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Neoteric Chaff Generation Method Of Fingerprint Fuzzy Vault, Nancy Singla, Sanjeev Sofat, Manvjeet Kaur Jan 2017

Neoteric Chaff Generation Method Of Fingerprint Fuzzy Vault, Nancy Singla, Sanjeev Sofat, Manvjeet Kaur

Turkish Journal of Electrical Engineering and Computer Sciences

Authentication using biometrics has an edge over traditional authentication mechanisms. Fuzzy vault is an eminent biometric cryptosystem technique that aims to protect a secret using a biometric template. Authorized users can, however, access the secret by providing the valid biometric. In a fuzzy vault, noise is incorporated in the form of chaff points in order to increase the security. While implementing fuzzy vault schemes in real scenarios, the most critical but computing-intensive and time-consuming task is chaff generation. In this paper, a neoteric method for chaff generation is proposed, which is less time-consuming in generating large numbers of chaff points.

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Low Complexity Link Level Performance Prediction For Simo Systems, Asif Khan, Alam Zaib, Shahid Khattak Jan 2017

Low Complexity Link Level Performance Prediction For Simo Systems, Asif Khan, Alam Zaib, Shahid Khattak

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a low-cost link level performance prediction technique is proposed for a single input and multiple output system. Receiver link level abstraction is used in system level simulations of large networks in order to reduce their complexity. Usually, a single lookup table is employed in link level abstraction to predict a receiver's performance under different channel conditions. In the presented work, the mean frame error rate curve of different diverse channels is proposed as the reference for performance prediction in single input multiple output systems. Its generation involves compression of the received code word into a single quality …

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A Cooperative Neural Network Approach For Enhancing Data Traffic Prediction, Salihu Aish Abdulkarim, Isa Abdullahi Lawal Jan 2017

A Cooperative Neural Network Approach For Enhancing Data Traffic Prediction, Salihu Aish Abdulkarim, Isa Abdullahi Lawal

Turkish Journal of Electrical Engineering and Computer Sciences

This paper addresses the problem of learning a regression model for the prediction of data traffic in a cellular network. We proposed a cooperative learning strategy that involves two Jordan recurrent neural networks (JNNs) trained using the firefly algorithm (FFA) and resilient backpropagation algorithm (Rprop), respectively. While the cooperative capability of the learning process ensures the effectiveness of the regression model, the recurrent nature of the neural networks allows the model to handle temporally evolving data. Experiments were carried out to evaluate the proposed approach using high-speed downlink packet access data demand and throughput measurements collected from different cell sites …

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Proposing A New Clustering Method To Detect Phishing Websites, Morteza Arab, Mohammad Karim Sohrabi Jan 2017

Proposing A New Clustering Method To Detect Phishing Websites, Morteza Arab, Mohammad Karim Sohrabi

Turkish Journal of Electrical Engineering and Computer Sciences

Phishing websites are fake ones that are developed by ill-intentioned people to imitate real and legal websites. Most of these types of web pages have high visual similarities to hustle the victims. The victims of phishing websites may give their bank accounts, passwords, credit card numbers, and other important information to the designers and owners of phishing websites. The increasing number of phishing websites has become a great challenge in e-business in general and in electronic banking specifically. In the present study, a novel framework based on model-based clustering is introduced to fight against phishing websites. First, a model is …

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A Predictive Modeling Approach For Improving Paddy Crop Productivity Using Data Mining Techniques, Anitha Arumugam Jan 2017

A Predictive Modeling Approach For Improving Paddy Crop Productivity Using Data Mining Techniques, Anitha Arumugam

Turkish Journal of Electrical Engineering and Computer Sciences

Agriculture has a great impact on the economy of developing countries. To provide food security for people, there is a need for improving the productivity of major crops. Rapidly changing climatic conditions and the cost of investment in agriculture are major barriers for small-holder farmers. The proposed research aims to develop a predictive model that provides a cultivation plan for farmers to get high yield of paddy crops using data mining techniques. Unlike statistical approaches, data mining techniques extract hidden knowledge through data analysis. The data set used in this research for mining process is real data collected from farmers …

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A Probabilistic Scenario-Based Framework For Solving Stochastic Dynamic Economic Emission Dispatch With Unit Commitment, Yachao Zhang, Kaipei Liu, Xiaobing Liao, Liang Qin, Xueli An Jan 2017

A Probabilistic Scenario-Based Framework For Solving Stochastic Dynamic Economic Emission Dispatch With Unit Commitment, Yachao Zhang, Kaipei Liu, Xiaobing Liao, Liang Qin, Xueli An

Turkish Journal of Electrical Engineering and Computer Sciences

This paper establishes a probabilistic scenario-based framework for the stochastic dynamic economic emission dispatch with unit commitment (SDEED-UC) problem, by considering wind power integration. The scenario generation and reduction method are implemented to describe wind power uncertainty. Accordingly, each wind power scenario is analyzed separately to determine the on/off status of the units. As for a predetermined significance level, the UC scheduling solution can be obtained with a probabilistic point of view, considering all the original scenarios. Then the SDEED problem is converted into a number of deterministic scheduling problems. For each scenario in the reduced set, an enhanced multiobjective …

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Discovering The Relationships Between Yarn And Fabric Properties Using Association Rule Mining, Peli̇n Yildirim, Derya Bi̇rant, Tuba Alpyildiz Jan 2017

Discovering The Relationships Between Yarn And Fabric Properties Using Association Rule Mining, Peli̇n Yildirim, Derya Bi̇rant, Tuba Alpyildiz

Turkish Journal of Electrical Engineering and Computer Sciences

Investigation of the effects of yarn parameters on fabric quality and finding important parameters to achieve desired fabric properties are important issues for the design process with the aim to meet the needs of the textile industry and the consumer for complex and specific requirements of functionality. Despite many statistical and mathematical studies that predict and reveal specific properties of utilized yarn and fabric materials, a number of challenges continue to exist when evaluated in many perspectives, such as discovering complex relationships among material properties in data. Data mining plays an important role in discovering hidden patterns from fabric data …

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A Random Number Generator For Lightweight Authentication Protocols: Xorshiftr+, Umut Can Çabuk, Ömer Aydin, Gökhan Dalkiliç Jan 2017

A Random Number Generator For Lightweight Authentication Protocols: Xorshiftr+, Umut Can Çabuk, Ömer Aydin, Gökhan Dalkiliç

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents the results of research that aims to find a suitable, reliable, and lightweight pseudorandom number generator for constrained devices used in the Internet of things. Within the study, three reduced versions of the xorshift+ generator are built. They are tested using the TestU01 suite as well as the NIST suite to measure their ability to produce randomness and performance values along with some other existing generators. The best of our reduced variations according to our tests, called the xorshiftR+, demonstrated great suitability for lightweight devices considering its randomness, performance, and resource usage.

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Stock Daily Return Prediction Using Expanded Features And Feature Selection, Hakan Gündüz, Zehra Çataltepe, Yusuf Yaslan Jan 2017

Stock Daily Return Prediction Using Expanded Features And Feature Selection, Hakan Gündüz, Zehra Çataltepe, Yusuf Yaslan

Turkish Journal of Electrical Engineering and Computer Sciences

Stock market prediction is a very noisy problem and the use of any additional information to increase accuracy is necessary. In this paper, for the stock daily return prediction problem, the set of features is expanded to include indicators not only for the stock to be predicted itself but also a set of other stocks and currencies. Afterwards, different feature selection and classification methods are utilized for prediction. The daily close returns of the 3 most traded stocks (GARAN, THYAO, and ISCTR) in Borsa İstanbul (BIST) are predicted using indicators computed on those stocks, indicators for all the other stocks …

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An Improved Omthd Technique For An N-Level Cascaded Multilevel Inverter With Adjustable Dc Sources, Hamidreza Toodeji Jan 2017

An Improved Omthd Technique For An N-Level Cascaded Multilevel Inverter With Adjustable Dc Sources, Hamidreza Toodeji

Turkish Journal of Electrical Engineering and Computer Sciences

Optimal minimization of total harmonic distortion (OMTHD) and selective harmonic elimination (SHE) switching techniques are usually employed to reduce generated harmonics of multilevel inverters. In the former technique, the THD of waveform is reduced without elimination of any harmonic order and the latter, in contrast, eliminates selected harmonic orders. In this paper, the harmonic elimination ability of the SHE technique is added to OMTHD and an improved OMTHD technique is proposed for an n-level cascaded multilevel inverter with adjustable DC sources. The main novelty of this switching technique is elimination of some harmonic orders, beside THD minimization. Moreover, optimal DC …

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On The Design Of Equal Division Single-Band Filtering Dividers With An Extended Transmission Line And Resistor As Isolation Elements, Zafar Bedar Khan, Huiling Zhao Jan 2017

On The Design Of Equal Division Single-Band Filtering Dividers With An Extended Transmission Line And Resistor As Isolation Elements, Zafar Bedar Khan, Huiling Zhao

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces a new scheme for effective output port isolation and return loss in RF-filtering divider design. The proposed design incorporates an extended transmission line and a conventional resistor as isolation elements. The technique has a simpler microstrip circuit implementation when it comes to the integration of a single-band band-pass filter with a Wilkinson power divider to achieve simultaneous filtering-dividing action. It is established that if a band-pass filter with a certain fractional-bandwidth is matched to 70.7 $\Omega $, a transmission line section and isolation resistor are sufficient for achieving reasonable output port return loss and isolation in the …

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Development Of Metal Oxide Arrester Block Using A Rare Earth Element For Very Fast Transient Overvoltage Applications, Kannadasan Raju, Valsalal Prasad, Jayavel Ramasamy Jan 2017

Development Of Metal Oxide Arrester Block Using A Rare Earth Element For Very Fast Transient Overvoltage Applications, Kannadasan Raju, Valsalal Prasad, Jayavel Ramasamy

Turkish Journal of Electrical Engineering and Computer Sciences

The protection ability of metal oxide arresters against switching, lightning, and steep current surges has been well proven. On the contrary, during the invasion of very fast transients, the existing arrester fails to operate due to delay in its initial response. In order to decrease the delay, it is imperative to improve the electrical properties of the arrester such as nonlinearity and voltage gradient with reduced capacitive effect. In this context, new arrester blocks are developed with the addition of a rare earth element, namely scandium trioxide (Sc$_{2}$O$_{3})$, and then sintered with a microwave sintering process. Owing to the uniform …

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New Patterson-Wiedemann Type Functions With 15 Variables In The Generalized Rotation-Symmetric Class, Selçuk Kavut Jan 2017

New Patterson-Wiedemann Type Functions With 15 Variables In The Generalized Rotation-Symmetric Class, Selçuk Kavut

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, it was shown that there is no Boolean function on 15 variables with nonlinearity greater than 16276 in the class of functions that are invariant under the action of GF(2$^{3})^{\ast }\times GF(2^{5})^{\ast }$. In this study, we consider some important subsets of this class and perform an efficient enumeration of the 15-variable Patterson-Wiedemann (PW) type functions with nonlinearity greater than the bent concatenation bound 16256 in the generalized classes of both 3-RSBFs and 5-RSBFs for which the corresponding search spaces are 2$^{28.2}$ and 2$^{47.85}$, respectively. For the case of 3-RSBFs, we find that there are 32 functions with nonlinearity …

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Effect Of Stator Permanent Magnet Thickness And Rotor Geometry Modifications On The Minimization Of Cogging Torque Of A Flux Reversal Machine, Bheeman Vidhya, Kandadai Nagaratnam Srinivas Jan 2017

Effect Of Stator Permanent Magnet Thickness And Rotor Geometry Modifications On The Minimization Of Cogging Torque Of A Flux Reversal Machine, Bheeman Vidhya, Kandadai Nagaratnam Srinivas

Turkish Journal of Electrical Engineering and Computer Sciences

This paper attempts to examine the effect of stator-rotor geometry on the minimization of cogging torque of a flux reversal generator (FRG). With respect to stator geometry, height (or thickness) of the permanent magnets of the stator poles was varied and cogging torque minimization was observed. With respect to rotor geometry, the following cases were considered: a) rotor pole arc variation and b) V-shaped punches on the rotor pole. The characterization of FRG under these cases for the observation of the effects on cogging torque was performed using three-dimensional finite element analysis. From the results of simulation, a model was …

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Probabilistic Day-Ahead System Marginal Price Forecasting With Ann For The Turkish Electricity Market, Erdem Özgüner, Osman Bülent Tör, Ali̇ Nezi̇h Güven Jan 2017

Probabilistic Day-Ahead System Marginal Price Forecasting With Ann For The Turkish Electricity Market, Erdem Özgüner, Osman Bülent Tör, Ali̇ Nezi̇h Güven

Turkish Journal of Electrical Engineering and Computer Sciences

This study presents a system day-ahead hourly market clearing price forecasting tool for the day-ahead (DA) market and a system DA hourly marginal price forecasting tool for the real-time market of the Turkish electric market (TEM). These forecasting tools are developed based on artificial neural networks (ANNs). A series of historical price data of the TEM are utilized to model and optimize the ANN structure and to develop the ANN-based price forecasting tool. The methodology used to select the optimum ANN architecture provides the minimum daily mean absolute percentage error for both day-ahead market prices in the TEM. Performances of …

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Dynamic Model To Predict Ac Critical Flashover Voltage Of Nonuniformly Polluted Insulators Under Thermal Ionization Conditions, Saeed Shahabi, Ahmad Gholami Jan 2017

Dynamic Model To Predict Ac Critical Flashover Voltage Of Nonuniformly Polluted Insulators Under Thermal Ionization Conditions, Saeed Shahabi, Ahmad Gholami

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a theoretical dynamic model based on the Hampton criterion and Mayr's equation for predicting the critical values of flashover on the surface of nonuniformly polluted cap and pin porcelain insulators. The nonuniform pollution layer on the surface of the insulator, the number of disk insulator units, and the geometry of the insulator such as diameter and ribs are the important factors used for prediction. Two types of pollution layer configuration, linear and graded, are introduced as nonuniform pollution layers. The influences of the nonuniform pollution layer on critical flashover voltage are investigated. Furthermore, a random value is …

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Automatic Reduction Of Periodic Noise In Images Using Adaptive Gaussian Star Filter, Seni̇ha Ketenci̇, Ali̇ Gangal Jan 2017

Automatic Reduction Of Periodic Noise In Images Using Adaptive Gaussian Star Filter, Seni̇ha Ketenci̇, Ali̇ Gangal

Turkish Journal of Electrical Engineering and Computer Sciences

The reduction of noise in images is a crucial issue and an inevitable preprocessing step in image analysis. Many diverse noise sources, which disrupt source images, exist in nature and through manmade devices. Periodic noise is one such disruption that has a periodic pattern in the spatial domain, causing hills in the image spectrum. In practice, quasiperiodic noise is commonly encountered instead of periodic noise. It has a more complex frequency spectrum, such as a star shape, in place of a pure delta shape in the frequency amplitude spectrum. In this study, we consider designing a star shape Gaussian filter …

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