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Articles 1351 - 1380 of 3020
Full-Text Articles in Physical Sciences and Mathematics
Neville Interpolation-Based Normal Estimation, Buse Meli̇s Özyildirim, Ulus Çevi̇k
Neville Interpolation-Based Normal Estimation, Buse Meli̇s Özyildirim, Ulus Çevi̇k
Turkish Journal of Electrical Engineering and Computer Sciences
Displaying useful and meaningful information from 3D data is known as volume rendering. Ray casting is one of the most frequently used direct volume rendering methods. It consists of data preparation, sampling, classification, compositing, and shading steps. Normal values are needed for efficient shading. However, 3D volumetric data are discrete and cannot be used directly for shading. Hence, the estimation of normal values, at each voxel on the surface, is needed for realistic shading. In normal estimation, the use of small voxel neighborhoods results in the staircase effect. On the other hand, the use of larger voxel neighborhoods causes loss …
Gica: Imperialist Competitive Algorithm With Globalization Mechanism For Optimization Problems, Yousef Abdi, Mahmoud Lak, Yousef Seyfari
Gica: Imperialist Competitive Algorithm With Globalization Mechanism For Optimization Problems, Yousef Abdi, Mahmoud Lak, Yousef Seyfari
Turkish Journal of Electrical Engineering and Computer Sciences
The imperialist competitive algorithm (ICA) is a recent global search strategy developed based on human social evolutionary phenomena in the real world. However, the ICA has the drawback of trapping in local optimum solutions when used for high-dimensional or complex multimodal functions. In order to deal with this situation, in this paper an improved ICA, named GICA, is proposed that can enhance ICA performance by using a new assimilation method and establishing a relationship between countries inspired by the globalization concept in the real world. The proposed algorithm is evaluated using a set of well-known benchmark functions for global optimization. …
A Symmetrically Feeding Structure For Dual-Polarized Feeds, Jinyuan Liu, Hui Deng, Bin Ding, Xiaolong Niu
A Symmetrically Feeding Structure For Dual-Polarized Feeds, Jinyuan Liu, Hui Deng, Bin Ding, Xiaolong Niu
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a symmetrically feeding structure for linear dual-polarized feeds for a compensated compact test range (CCR) and a corresponding wideband balun are put forward. $TM_{01}$ and $TE_{21} $ modes within the circular feeding waveguide are compressed due to its electrical balance. The polarization purity of feeds is then improved. Thus, the level of cross-polarization can be very low, which is the key requirement for CCR. A new wideband balun that acts as a power-divider and phase shifter with low amplitude unbalance and phase unbalance is designed for the new feeding structure. The return loss equation derived from an …
A Measurement Study Of Internet Exchange Points (Ixps): History And Future Prediction, Mohammad Masoud, Yousef Jaradat, Ismael Jannoud
A Measurement Study Of Internet Exchange Points (Ixps): History And Future Prediction, Mohammad Masoud, Yousef Jaradat, Ismael Jannoud
Turkish Journal of Electrical Engineering and Computer Sciences
Internet exchange points (IXPs) emerged to remedy the deficiency of peering connections among autonomous systems (ASes). IXPs play an important role in reducing the cost of transit connections over the Internet. This work attempts to study the popularity of IXPs over the Internet. This work consists of two main parts. The first part is a measurement study of multihistorical snapshots of IXPs. These historical data have been harvested for different European IXPs with emphasis on Amsterdam (AMS-IX) IXP. In the second part, two nonlinear autoregressive exogenous (NARX) back-propagation neural network models (BPNN) have been implemented to predict the following: the …
Analysis Of Reconstruction Performance Of Magnetic Resonance Conductivity Tensor Imaging (Mrcti) Using Simulated Measurements, Evren Deği̇rmenci̇, Behçet Murat Eyüboğlu
Analysis Of Reconstruction Performance Of Magnetic Resonance Conductivity Tensor Imaging (Mrcti) Using Simulated Measurements, Evren Deği̇rmenci̇, Behçet Murat Eyüboğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Magnetic resonance conductivity tensor imaging (MRCTI) was proposed recently to produce electrical conductivity images of anisotropic tissues. Similar to magnetic resonance electrical impedance tomography (MREIT), MRCTI uses magnetic field and boundary potential measurements obtained utilizing magnetic resonance imaging techniques. MRCTI reconstructs tensor images of anisotropic conductivity whereas MREIT reconstructs isotropic conductivity images. In this study, spatial resolution and linearity of five recently proposed MRCTI algorithms are evaluated using simulated measurements gathered from three different computer models. The results show that all five algorithms have quite similar reconstruction performances. Since the AB$_{z}$S algorithm is easier to apply compared to the other …
Performance Comparison Of Axial-Flux-Modulated Motor With Two Pole-Slot Combinations, Huijuan Liu, Yue Hao, Weinong Fu
Performance Comparison Of Axial-Flux-Modulated Motor With Two Pole-Slot Combinations, Huijuan Liu, Yue Hao, Weinong Fu
Turkish Journal of Electrical Engineering and Computer Sciences
Axial-flux-modulated motors (AFMMs) with two pole-slot combinations are presented and analyzed quantitatively. They all have new topology structures, and their design rules differ from those of the traditional machine. The concentrated stator windings are designed to reduce the end length and copper losses; therefore, the efficiency of the motors can be improved. Special iron segments in the air-gap are used to modulate the magnetic field. The two proposed AFMMs have 36 stator slots and 30 stator slots, respectively, and the pole-slot combinations are 6 poles for 36 slots and 4 poles for 30 slots. This paper focuses on the comparative …
A Data-Aware Cognitive Engine For Scheduling Data Intensive Applications In A Grid, Vijaya Nagarajan, Maluk Mohamed Mulk Abdul
A Data-Aware Cognitive Engine For Scheduling Data Intensive Applications In A Grid, Vijaya Nagarajan, Maluk Mohamed Mulk Abdul
Turkish Journal of Electrical Engineering and Computer Sciences
Data-intensive applications produce huge amounts of data that need to be stored, analyzed, and interpreted. A data grid serves as a cost-effective infrastructure for solving these data-intensive applications. Existing scheduling strategies are best suited for handling compute-intensive applications, although they lack in performance while handling data-intensive applications. In this work, a novel mechanism of incorporating cognitive science in a data grid is proposed for scheduling data-intensive workflows. A unique model is derived in which a cognitive engine (CE) is built into the middleware of the data grid. The intelligent agents present in the CE handle the request for data sets …
A Computer-Based Modification Solution For Old Type Of Electro-Controlled Mechanical Jacquard Looms, Mahmut Aykaç, Ercan Yildiz, Abdurrahman Oğuz
A Computer-Based Modification Solution For Old Type Of Electro-Controlled Mechanical Jacquard Looms, Mahmut Aykaç, Ercan Yildiz, Abdurrahman Oğuz
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, we modified the old type of electro-controlled mechanical Jacquard looms for the carpet weaving industry by substituting a Jacquard controller with a modern computer running software called the "Weaving Control System", which has also been developed in the context of this study. By this modification, the Jacquard controller, which requires expensive electronic components and maintenance, has been discarded, and a contemporary computer-based solution that is easy to control and use, and cheap to install and maintain, has been employed in the place of the Jacquard controller. Even though the proposed solution has been tested on the Schleicher-type …
Transmission Power Control Using State Estimation-Based Received Signal Strength Prediction For Energy Efficiency In Wireless Sensor Networks, Ramakrishnan Sabitha, Krishna Bhuma, Thangavelu Thyagarajan
Transmission Power Control Using State Estimation-Based Received Signal Strength Prediction For Energy Efficiency In Wireless Sensor Networks, Ramakrishnan Sabitha, Krishna Bhuma, Thangavelu Thyagarajan
Turkish Journal of Electrical Engineering and Computer Sciences
In battery-operated wireless sensor networks, the quality of service requirements such as throughput and energy efficiency must be stringently maintained while the least amount of energy is consumed. Since a major portion of energy is spent by the transceiver operations, transmission power control (TPC) in the medium access control (MAC) layer can bring about considerable energy efficiency. Since TPC algorithms will have a direct impact on the received signal strength index (RSSI) at the receiver, RSSI is the primary input parameter for any TPC algorithm. The objective of the proposed work is to decide on the exact value of transmission …
Modeling Hybrid Modulation Strategy With Nearest Leveled Vector Switching Pattern In Space Vector Control Technique For Multilevel Inverters, Rohith Balaji Jonnala, Sai Babu Choppavarapu
Modeling Hybrid Modulation Strategy With Nearest Leveled Vector Switching Pattern In Space Vector Control Technique For Multilevel Inverters, Rohith Balaji Jonnala, Sai Babu Choppavarapu
Turkish Journal of Electrical Engineering and Computer Sciences
The multilevel inverter's impact in the area of power electronics is augmented because of its nimble nature. This paper presents an efficient switching pattern for multilevel inverters using the nearest leveled vector (NLV) strategy through a space vector control (SVC) technique. The objective is to reduce the total harmonic distortions by generating an optimal switching sequence with the newly introduced NLV-SVC for multilevel inverters. The proposed NLV modulation is applied for an asymmetrical multilevel inverter, which has a high number of levels with reduced switch count, sources, and lower switching losses. The effectiveness of the proposed method is verified on …
Turkish Synonym Identification From Multiple Resources: Monolingual Corpus, Mono/Bilingual Online Dictionaries, And Wordnet, Tuğba Yildiz, Banu Di̇ri̇, Savaş Yildirim
Turkish Synonym Identification From Multiple Resources: Monolingual Corpus, Mono/Bilingual Online Dictionaries, And Wordnet, Tuğba Yildiz, Banu Di̇ri̇, Savaş Yildirim
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a model is proposed to determine synonymy by incorporating several resources. The model extracts the features from monolingual online dictionaries, a bilingual online dictionary, WordNet, and a monolingual Turkish corpus. Once it has built a candidate list, it determines the synonymy for a given word by means of those features. All these resources and the approaches are evaluated. Taking all features into account and applying machine learning algorithms, the model shows good performance of F-measure with 81.4%. The study contributes to the literature by integrating several resources and attempting the first corpus-driven synonym detection system for Turkish.
Classifications Of Disturbances Using Wavelet Transform And Support Vector Machine, Neda Hajibandeh, Faramarz Faghihi, Hossein Ranjbar, Hesam Kazari
Classifications Of Disturbances Using Wavelet Transform And Support Vector Machine, Neda Hajibandeh, Faramarz Faghihi, Hossein Ranjbar, Hesam Kazari
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a new method to detect and classify all kinds of faults, capacitor switching, and load switching in a power system network based on wavelet transform and support vector machines (SVMs). In this regard, a sample of a power system is simulated via MATLAB/Simulink, and by reading the voltage of the point of common coupling and using the wavelet transform, the differences of the outputs of the wavelet transform are investigated. The SVM approach is employed to distinguish the type of the transient (capacitor switching, fault, and/or load switching) in use for the high level outputs of the …
An Optimized Buffer Insertion Algorithm With Delay-Power Constraints For Vlsi Layouts, Chessda Uttraphan, Nasir Shaikh-Husin, Mohamed Khalil Hani
An Optimized Buffer Insertion Algorithm With Delay-Power Constraints For Vlsi Layouts, Chessda Uttraphan, Nasir Shaikh-Husin, Mohamed Khalil Hani
Turkish Journal of Electrical Engineering and Computer Sciences
We propose a grid-graph algorithm for interconnect routing and buffer insertion in nanometer VLSI layout designs. The algorithm is designed to handle multiconstraint optimizations, namely timing performance and power dissipation. The proposed algorithm is called HRTB-LA, which stands for hybrid routing tree and buffer insertion with look-ahead. In recent VLSI designs, interconnect delay has become a dominant factor compared to gate delay. The well-known technique to minimize the interconnect delay is by inserting buffers along the interconnect wires. However, the buffer itself consumes power and it has been shown that power dissipation overhead due to buffer insertions is significantly high. …
An Effective Empirical Approach To Voip Traffic Classification, Nazar Abbas Saqib, Yaqoot Shakeel, Moazzam Ali Khan, Hasan Mehmood, Muhammad Zia
An Effective Empirical Approach To Voip Traffic Classification, Nazar Abbas Saqib, Yaqoot Shakeel, Moazzam Ali Khan, Hasan Mehmood, Muhammad Zia
Turkish Journal of Electrical Engineering and Computer Sciences
It is beneficial for telecommunication authorities and Internet service providers (ISPs) to classify and detect voice traffic. It can help them to block unsubscribed users from using their services, which saves them huge revenues. Voice packets can be detected easily, but it becomes complicated when the application or port information in the packet header is hidden due to some secure mechanism such as encryption. This work provides effective voice packet classification and detection based on behavioral and statistical analysis, which is independent of any application, security protocol, or encryption mechanism. First we have made initial assessments through packet feature analysis …
A Metaheuristic Based On The Tabu Search For Hardware-Software Partitioning, Mehdi Jemai, Sonia Dimassi, Bouraoui Ouni, Abdellatif Mtibaa
A Metaheuristic Based On The Tabu Search For Hardware-Software Partitioning, Mehdi Jemai, Sonia Dimassi, Bouraoui Ouni, Abdellatif Mtibaa
Turkish Journal of Electrical Engineering and Computer Sciences
Several metaheuristics have become increasingly interesting in solving combinatorial problems. In this paper, we present an algorithm involving a metaheuristic based on tabu search and binary search trees to address the problem of hardware-software partitioning. Metaheuristics do not guarantee an optimum solution, but they can produce acceptable solutions in a reasonable time. Our proposed algorithm seeks to find the efficient hardware-software partitioning that minimizes the logic area of a system on a programmable chip under the condition of time constraints. Our goal is to have a better trade-off between the logic area of the application and its execution time. Finally, …
Implementation Of A Web-Based Service For Mobile Application Risk Assessment, Asim Si̇nan Yüksel, Mehmet Erkan Yüksel, Ahmet Sertbaş, Abdül Hali̇m Zai̇m
Implementation Of A Web-Based Service For Mobile Application Risk Assessment, Asim Si̇nan Yüksel, Mehmet Erkan Yüksel, Ahmet Sertbaş, Abdül Hali̇m Zai̇m
Turkish Journal of Electrical Engineering and Computer Sciences
The Android operating system has increased in popularity and has been increasing its shares in the smart phone market. Users can carry out their daily work such as paying bills, being social, and sharing photos through mobile applications. These applications have access to sensitive information about the user, such as location, contacts, call logs, and SMS messages. However, the users have no knowledge of the applications or the personal information these applications have access to. Even if an application is not malware or does not have malicious behavior, it can compromise the security and privacy of the user by accessing …
A Methodology To Include Real-Life Failure Data In The Failure Rate Estimation Of Power Distribution Systems, Mojtaba Gilvanejad, Hossein Askarian Abyaneh, Kazem Mazlumi
A Methodology To Include Real-Life Failure Data In The Failure Rate Estimation Of Power Distribution Systems, Mojtaba Gilvanejad, Hossein Askarian Abyaneh, Kazem Mazlumi
Turkish Journal of Electrical Engineering and Computer Sciences
Random failure rates are usually assumed as constant values in reliability calculations. In this paper, this topic is investigated using stochastic models of uncertain phenomena like lightning, cold load pickup, and overloading, which result in random failures. An algorithm is developed to estimate the random failure rates in distribution networks during their lifetime. This algorithm stochastically generates the random failures as well as sustained failures as a result of equipment wear-out state due to the aging process and finally estimates the total number of temporary/sustained failures in a period of the network lifetime. The results of applying this algorithm to …
Implementation Of A Flywheel Energy Storage System For Space Applications, Reşat Çeli̇kel, Mehmet Özdemi̇r, Ömür Aydoğmuş
Implementation Of A Flywheel Energy Storage System For Space Applications, Reşat Çeli̇kel, Mehmet Özdemi̇r, Ömür Aydoğmuş
Turkish Journal of Electrical Engineering and Computer Sciences
A satellite power system requires solar panels to provide energy and orientation. There are two regions in the orbital path of the satellite: the dark and bright region. The energy is provided by solar panels in the bright region and by flywheel energy storage system (FESS) in the dark region. Brushless DC (BLDC) motors are widely used in the FESS due to their low weight, high power density, high efficiency, high reliability, and high speed. Some mechanical resonances may occur due to physical features of the mechanical parts. Therefore, the current of the BLDC is dramatically increased because of the …
A 3d Simulation Of The Formation Of Primary Platelet Thrombi Based On A Hybrid Computational Model, Chaoqing Ma, Oubong Gwun
A 3d Simulation Of The Formation Of Primary Platelet Thrombi Based On A Hybrid Computational Model, Chaoqing Ma, Oubong Gwun
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, the study of thrombosis simulation based on computational models has been one of the most popular research areas. In this paper, a 3D simulation method based on a hybrid model is proposed for platelet thrombus formation. The flow of platelets is modeled in a macroscale submodel using Navier--Stokes equations and the physiological processes such as adhesion and aggregation of platelets are modeled in a microscale submodel. In the adhesion and aggregation phases, the attraction of platelets due to blood coagulation factors (von Willebrand factor) is modeled using the external force, and the conversion from unstable aggregation to stable aggregation …
Performance Evaluation Of Simple Csrz-Qdpsk Transmitter Configurations For 20-Gbps Pon Applications, Rimmya Chitravelu, Ganesh Madhan Muthu
Performance Evaluation Of Simple Csrz-Qdpsk Transmitter Configurations For 20-Gbps Pon Applications, Rimmya Chitravelu, Ganesh Madhan Muthu
Turkish Journal of Electrical Engineering and Computer Sciences
The performance of 1 and 2 Mach--Zehnder modulator (MZM)-based simple carrier suppressed return to zero differential quadrature phase shift keying (CSRZ-QDPSK) transmitters is analyzed in a 20 Gb/s single-mode fiber optic link. The link's performance under the transmitter schemes is evaluated by analyzing the received constellation, eye diagram, quality factor, and eye opening penalty (EOP) in a passive optical networks (PON) scenario. It is observed that the simple transmitter provides performance closer to the case of the standard 3 MZM CSRZ-QDPSK-based transmitter reported in the literature and implemented in experiments.
Electrical Design And Testing Of A 500 Kw Doubly Fed Induction Generator For Wind Power Applications, Cenk Ulu, Güven Kömürgöz
Electrical Design And Testing Of A 500 Kw Doubly Fed Induction Generator For Wind Power Applications, Cenk Ulu, Güven Kömürgöz
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, the electrical design and testing of a 500 kW doubly fed induction generator (DFIG) is presented, developed in the context of the MILRES (Turkish National Wind Energy Systems) Project. The main objective of the MILRES Project is to encourage locally produced equipment for wind power systems. Therefore, in the DFIG design, the standard construction capabilities of the local machine manufacturers are especially taken into consideration. In this way, it is aimed that the designed DFIG can easily and cost-effectively be manufactured by local machine manufacturers in Turkey. In the DFIG design procedure, initially, an analytical design of …
Dvcc-Based Floating Capacitance Multiplier Design, Hali̇l Alpaslan
Dvcc-Based Floating Capacitance Multiplier Design, Hali̇l Alpaslan
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a floating capacitance multiplier including two multioutput differential voltage current conveyors, two grounded resistors, and a grounded capacitor is proposed. The proposed floating capacitance multiplier can realize high capacitor values with two small-valued resistors. It is more suitable for integrated circuit technology because it has only grounded passive components without needing any critical passive component matching conditions. Its performances are examined with several simulations using the SPICE program. As an application example, a third-order notch filter using three resistors and three capacitors is given.
An Advanced Robust Fault-Tolerant Tracking Control For A Doubly Fed Induction Generator With Actuator Faults, Samir Abdelmalek, Linda Barazane, Abdelkader Larabi
An Advanced Robust Fault-Tolerant Tracking Control For A Doubly Fed Induction Generator With Actuator Faults, Samir Abdelmalek, Linda Barazane, Abdelkader Larabi
Turkish Journal of Electrical Engineering and Computer Sciences
Fault-tolerant controller (FTC) designs for doubly fed induction generators (DFIGs) with actuator faults have recently gained considerable attention due to their important role in maintaining the safety and reliability of DFIG-based wind turbines via configured redundancy. The objective of this paper is to propose a novel active fault-tolerant tracking control strategy for a DFIG subject to actuator faults. The proposed strategy consists of first designing a proportional integral observer (PIO) for simultaneous system states and fault estimation and then secondly the FTC, which depends on the estimated states and faults. The objective of such a controller is to drive the …
Threshold Distance-Based Cluster Routing Protocols For Static And Mobile Wireless Sensor Networks, Padmavati Khandnor, Trilok Aseri
Threshold Distance-Based Cluster Routing Protocols For Static And Mobile Wireless Sensor Networks, Padmavati Khandnor, Trilok Aseri
Turkish Journal of Electrical Engineering and Computer Sciences
In cluster-based wireless sensor network routing protocols, when the cluster head transfers data based on single hop transmission to the sink node, then the cluster heads that are farther away deplete more energy as compared to nearby cluster heads. This condenses load balancing in the network. If the cluster heads collaborate with each other and transfer data based on multihop transmission, then the cluster heads nearer to the sink node are burdened with significant relay traffic and deplete energy much faster, which causes a network coverage problem also known as a hot spot problem. To avoid both of the above …
Experimental Evaluation And Fdtd Method For Predicting Electromagnetic Fields In The Near Zone Radiated By Power Converter Systems, Mohammed Laour, Redouane Tahmi, Christian Vollaire
Experimental Evaluation And Fdtd Method For Predicting Electromagnetic Fields In The Near Zone Radiated By Power Converter Systems, Mohammed Laour, Redouane Tahmi, Christian Vollaire
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the study of conducted electromagnetic interference (EMI) currents flowing through the power cables of a DC-DC converter system and its correlation with the near field radiated from these cables. The radiated emission measurement contains a common mode (CM) and a differential mode (DM), and accurate separation of the radiated emissions of these two modes is necessary. The finite-difference time-domain (FDTD) method is used to predict the electromagnetic radiation caused by CM currents and DM currents. An experimental bench has been designed to allow access to the measurement of EMI disturbances at various sensitive places. The CM and …
Design And Implementation Of A Modified Communication Disturbance Observer For Teleoperation Systems, Zahra Zeinaly, Amin Ramezani, Sadjaad Ozgoli
Design And Implementation Of A Modified Communication Disturbance Observer For Teleoperation Systems, Zahra Zeinaly, Amin Ramezani, Sadjaad Ozgoli
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a novel structure for a communication disturbance observer in teleoperation systems is proposed to achieve robust stability. A time delay compensation method based on the concept of network disturbance and a communication disturbance observer (CDOB) has been proposed in past research. Unlike model-based approaches, it works without a time delay model. Therefore, it can be implemented in teleoperation systems with unknown and time-varying delay. However, it has been observed that the system model errors and external disturbances seriously affect the steady-state characteristics. Hence, in this paper, to achieve robustness against disturbance and model uncertainty, the structure of …
Investigation Of Secondary Cooling Design Enhancements In Thermally Limited Compact Notebooks, Muhammad Azhar Ali Khan, Eray Uzgören, Ali̇ Muhtaroğlu
Investigation Of Secondary Cooling Design Enhancements In Thermally Limited Compact Notebooks, Muhammad Azhar Ali Khan, Eray Uzgören, Ali̇ Muhtaroğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Thermal design enhancements in a thermally limited compact notebook system are investigated in this paper. System temperature, power, and fan speed are characterized under a range of activity levels. A finite element model is developed, and validated against measurements. Design enhancements improve cooling with minimum intrusion to the existing mechanical design. A passive secondary heat pipe in the system reduces the CPU temperature by 5 $^{\circ}$C, and improves the system performance through increased CPU + Graphics and Memory Controller Hub (GMCH) thermal design power (TDP) by 6.4%. When such a secondary heat pipe is considered with an integrated off-the-shelf Peltier …
Regional Ionospheric Trend Statistics: Ionolab-Pdf, Ozan Köroğlu, Feza Arikan
Regional Ionospheric Trend Statistics: Ionolab-Pdf, Ozan Köroğlu, Feza Arikan
Turkish Journal of Electrical Engineering and Computer Sciences
The ionosphere plays an important role for HF bands, space-based positioning systems, satellite communication, and propagation. The variability of the ionosphere has a complex spatiotemporal characteristic, which depends on statistical parameters. Total electron content (TEC) is one of the major observables for investigating and determining this variability. In this study, spatiotemporal within-the-hour statistical characteristics of TEC are determined for Turkey, which is located in midlatitude, using the TEC estimates from the Turkish National Permanent GPS Network-Active between the years 2009 and 2012. The TEC values have strong hourly, seasonal, and positional dependence on east-west direction, and the trend shifts according …
Error Sources And Measurement Uncertainties In Outdoor Testing Of Bipv Modules, Kivanç Başaran
Error Sources And Measurement Uncertainties In Outdoor Testing Of Bipv Modules, Kivanç Başaran
Turkish Journal of Electrical Engineering and Computer Sciences
Although building-integrated photovoltaic (BIPV) systems have great potential, investment in this field is not at the desired level. There are two main reasons for this: the lack of technical analysis and economic reasons. Manufacturers and investors utilize datasheets of modules to determine the systems performance, which is determined at standard test conditions (STCs). However, there are apparent differences between STCs and outdoor measurements. Most studies in the field of BIPV system analysis have only focused on long-term outdoor measurements. Besides that, uncertainty of measurements is necessary to achieve scientific results. The aim of this study is to emphasize the importance …
Design Optimization Of A ĆUk Dc/Dc Converter Based On Reliability Constraints, Amirreza Zarrin Gharehkoushan, Mehdi Abapour, Amir Farakhor
Design Optimization Of A ĆUk Dc/Dc Converter Based On Reliability Constraints, Amirreza Zarrin Gharehkoushan, Mehdi Abapour, Amir Farakhor
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, power electronic converters have widely been used in various applications. This has led to concerns about the reliability of power converters and, as a result, their optimal design has attracted a lot of attention. However, the reliability-based optimal design of the Ćuk DC-DC converter has not yet been studied. A new methodology is presented here for the optimal design of the Ćuk converter based on reliability constraints. In this study, the converter is designed to minimize power losses in order to maximize the mean time to failure of the converter. A genetic algorithm is used as the optimization technique, …