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2017

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Articles 8221 - 8250 of 8344

Full-Text Articles in Engineering

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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Effects Of Nonaerated Circulation Water Velocity On Nutrient Release From Aquaculture Pond Sediments, Xiangju Cheng, Dantong Zhu, Xixi Wang, Deguang Yu, Jun Xie Jan 2017

Effects Of Nonaerated Circulation Water Velocity On Nutrient Release From Aquaculture Pond Sediments, Xiangju Cheng, Dantong Zhu, Xixi Wang, Deguang Yu, Jun Xie

Civil & Environmental Engineering Faculty Publications

Sustaining good water quality in aquaculture ponds is vital. Without an aerator, the dissolved oxygen in ponds comes primarily from mass transfer at the water-ambient atmosphere interface. As sediment can seriously affect water quality, this study used indoor experiments to examine the nutrient (nitrogen and phosphorus) release mechanisms and fluxes from sediment in aquaculture ponds with moving water but no aeration. The results showed that the ammonia nitrogen (NH3-N) concentration in the overlying water was inversely proportional to flow velocity and that a higher flow velocity tended to result in a lower concentration in the overlying water, a …

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Upscaling Stem To Community-Level Transpiration For Two Sand-Fixing Plants: Salix Gordejevii And Caragana Microphylla, Limin Duan, Yang Li, Xue Yan, Tingxi Liu, Xixi Wang Jan 2017

Upscaling Stem To Community-Level Transpiration For Two Sand-Fixing Plants: Salix Gordejevii And Caragana Microphylla, Limin Duan, Yang Li, Xue Yan, Tingxi Liu, Xixi Wang

Civil & Environmental Engineering Faculty Publications

The information on transpiration is vital for sustaining fragile ecosystem in arid/semiarid environment, including the Horqin Sandy Land (HSL) located in northeast China. However, such information is scarce in existing literature. The objectives of this study were to: (1) measure sap flow of selected individual stems of two sand-fixing plants, namely Salix gordejevii and Caragana microphylla, in HSL; and (2) upscale the measured stem-level sap flow for estimating the community-level transpiration. The measurements were done from 1 May to 30 September 2015 (i.e., during the growing season). The upscaling function was developed to have one dependent variable, namely sap …

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Modeling Algae Powered Neighborhood Through Gis And Bim Integration, Florina Dutt, Steven Jige Quan, Erik Woodworth, Daniel Castro-Lacouture, Ben J. Stuart, Perry Pei-Ju Yang Jan 2017

Modeling Algae Powered Neighborhood Through Gis And Bim Integration, Florina Dutt, Steven Jige Quan, Erik Woodworth, Daniel Castro-Lacouture, Ben J. Stuart, Perry Pei-Ju Yang

Civil & Environmental Engineering Faculty Publications

This paper aims to propose a modeling method for algae powered neighborhoods through GIS-BIM integration. In the first part of the paper, the applicability of different types of algae systems in an urban neighborhood are studied. The various systems of algae provide different strengths and weakness that affect their performance and suitability for given urban scenarios. Through extensive literature review, the variables that affect the performance of the micro-algae in the built environment are identified, with a focus on flat-panel photo bio-reactors and tubular photobioreactors. A previous GIS model for data management, performance analysis and design of the algae systems …

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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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Bayesian Estimation Of Discrete-Time Cellular Neural Network Coefficients, Hakan Meti̇n Özer, Ati̇lla Özmen, Habi̇b Şenol Jan 2017

Bayesian Estimation Of Discrete-Time Cellular Neural Network Coefficients, Hakan Meti̇n Özer, Ati̇lla Özmen, Habi̇b Şenol

Turkish Journal of Electrical Engineering and Computer Sciences

A new method for finding the network coefficients of a discrete-time cellular neural network (DTCNN) is proposed. This new method uses a probabilistic approach that itself uses Bayesian learning to estimate the network coefficients. A posterior probability density function (PDF) is composed using the likelihood and prior PDFs derived from the system model and prior information, respectively. This posterior PDF is used to draw samples with the help of the Metropolis algorithm, a special case of the Metropolis-Hastings algorithm where the proposal distribution function is symmetric, and resulting samples are then averaged to find the minimum mean square error (MMSE) …

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Turkish Entity Discovery With Word Embeddings, Murat Kalender, Emi̇n Erkan Korkmaz Jan 2017

Turkish Entity Discovery With Word Embeddings, Murat Kalender, Emi̇n Erkan Korkmaz

Turkish Journal of Electrical Engineering and Computer Sciences

Entity-linking systems link noun phrase mentions in a text to their corresponding knowledge base entities in order to enrich a text with metadata. Wikipedia is a popular and comprehensive knowledge base that is widely used in entity-linking systems. However, long-tail entities are not popular enough to have their own Wikipedia articles. Therefore, a knowledge base created by using Wikipedia entities would be limited to only popular entities. In order to overcome the knowledge base coverage limitation of Wikipedia-based entity-linking systems, this paper presents an entity-discovery system that can detect semantic types of entities that are not defined in Wikipedia. The …

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A Cnfet Full Adder Cell Design For High-Speed Arithmetic Units, Mokhtar Mohammadi Ghanaghestani, Behnam Ghavami, Honeya Salehpour Jan 2017

A Cnfet Full Adder Cell Design For High-Speed Arithmetic Units, Mokhtar Mohammadi Ghanaghestani, Behnam Ghavami, Honeya Salehpour

Turkish Journal of Electrical Engineering and Computer Sciences

Carbon nanotube field-effect transistors (CNFETs) utilize an array of carbon nanotubes as the channel material instead of bulk silicon in the traditional MOSFET structure, which holds great promise for the future of integrated circuits. In this paper, a full adder cell based on a parallel design using CNFETs is presented. The main objective of designing this full adder cell is to reduce critical path delay in CNFET-based adder circuits. The proposed design positively affects speed and power consumption by shortening the data path. In order to evaluate the proposed design, several simulations were performed with different load capacitors, frequencies, and …

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A Ternary Zero-Correlation Zone Sequence Sets Construction Procedure, Mouad Addad, Ali Djebbari Jan 2017

A Ternary Zero-Correlation Zone Sequence Sets Construction Procedure, Mouad Addad, Ali Djebbari

Turkish Journal of Electrical Engineering and Computer Sciences

In the present paper, we propose ternary zero-correlation zone (ZCZ) sequence sets with ideal correlation properties for phase shifts within the ZCZ. The proposed ternary ZCZ sequence sets can be constructed from binary mutually orthogonal complementary sets (MOCS) and ternary perfect sequences.

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Analysis Of Feature Detector And Descriptor Combinations With A Localization Experiment For Various Performance Metrics, Ertuğrul Bayraktar, Pinar Boyraz Jan 2017

Analysis Of Feature Detector And Descriptor Combinations With A Localization Experiment For Various Performance Metrics, Ertuğrul Bayraktar, Pinar Boyraz

Turkish Journal of Electrical Engineering and Computer Sciences

The purpose of this study is to provide a detailed performance comparison of feature detector/descriptor methods, particularly when their various combinations are used for image-matching. The localization experiments of a mobile robot in an indoor environment are presented as a case study. In these experiments, 3090 query images and 127 dataset images were used. This study includes five methods for feature detectors (features from accelerated segment test (FAST), oriented FAST and rotated binary robust independent elementary features (BRIEF) (ORB), speeded-up robust features (SURF), scale invariant feature transform (SIFT), and binary robust invariant scalable keypoints (BRISK)) and five other methods for …

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Design And Realization Of A Novel Planar Array Antenna And Low Power Lna For Ku-Band Small Satellite Communications, Lida Kouhalvandi, Osman Ceylan, Selçuk Paker, Hasan Bülent Yağci Jan 2017

Design And Realization Of A Novel Planar Array Antenna And Low Power Lna For Ku-Band Small Satellite Communications, Lida Kouhalvandi, Osman Ceylan, Selçuk Paker, Hasan Bülent Yağci

Turkish Journal of Electrical Engineering and Computer Sciences

This article presents both a four-element novel microstrip array antenna and a low noise amplifier (LNA) for a Ku-band small satellite receiver. It includes all design details with measurement results of the fabricated array antenna and LNA. Measured minimum and maximum gains of the proposed antenna are 10.1 and 10.9 dBi in 11.9-12.9 GHz band frequency. The designed LNA has a noise figure lower than 1.5 dB and gain higher than 8 dB (at 2 V, 10 mA biasing). In order to reduce the design period and cost, discrete components are chosen and a hetero-junction FET is used as the …

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An Extremely Wideband Radome-Enclosed Cylindrical Dipole Antenna For Wireless Communication, Tariq Rahim, Jiadong Xu Jan 2017

An Extremely Wideband Radome-Enclosed Cylindrical Dipole Antenna For Wireless Communication, Tariq Rahim, Jiadong Xu

Turkish Journal of Electrical Engineering and Computer Sciences

A radome-enclosed extremely wideband cylindrical dipole antenna for wireless communications applications was proposed with a simple structure. The antenna is fed at the center with the help of a coaxial cable through the lower hollow metallic pole. The feed area is composed of cones at both sides in order to obtain wideband impedance matching. The proposed antenna can cover 1.8 GHz to 28 GHz with S11 of less than -10 dB and excellent stable omnidirectional radiation characteristics. However, at high frequencies, some ripples are introduced in the radiation pattern. The frequency band of the cylindrical dipole antenna can be controllable …

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Design And Operation Of A Multifunction Photovoltaic Power System With Shunt Active Filtering Using A Single-Stage Three-Phase Multilevel Inverter, Serkan Sezen, Ahmet Aktaş, Mehmet Uçar, Engi̇n Özdemi̇r Jan 2017

Design And Operation Of A Multifunction Photovoltaic Power System With Shunt Active Filtering Using A Single-Stage Three-Phase Multilevel Inverter, Serkan Sezen, Ahmet Aktaş, Mehmet Uçar, Engi̇n Özdemi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the control of a multifunction grid-connected photovoltaic (PV) system with a three-phase three-level (3L) neutral point clamped (NPC) inverter is proposed, which can perform shunt active filtering. Normally, the shunt active filtering is achieved by detecting the harmonic and reactive currents of the nonlinear load and then injecting the compensating current into the grid. Therefore, the proposed system can inject PV power to a grid with power factor correction and current harmonic filtering features simultaneously. In addition, a single-stage compact and efficient transformerless power conversion topology is used in this paper for the grid-connected solar PV system …

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