A Problem Approximation Surrogate Model (Pasm) For Fitness Approximation In Optimizing The Quantization Table For The Jpeg Baseline Algorithm, Vinoth Kumar Balasubramanian, Karpagam Manavalan
Turkish Journal of Electrical Engineering and Computer Sciences
The quantization table in the baseline Joint Photographic Experts Group (JPEG) algorithm plays an important role in compression/quality trade-off. Hence the detection of the optimal quantization table is viewed as an optimization problem. The genetic algorithm (GA) is an attractive optimization tool by many researchers for this application due to its ability in dealing with complex problems. In spite of its advantages, the GA requires more computation time to achieve an optimal solution if it has an expensive fitness evaluation. This paper proposes a problem approximation surrogate model (PASM) for fitness approximation to assist the GA in optimizing the quantization …
A 0.18-$\Mu $M Current-Mode Asynchronous Sigma-Delta Modulator Design,
2016
TÜBİTAK
A 0.18-$\Mu $M Current-Mode Asynchronous Sigma-Delta Modulator Design, Balkir Kayaalti, Ömer Ceri̇d, Günhan Dündar
Turkish Journal of Electrical Engineering and Computer Sciences
In this study a first-order asynchronous current-mode sigma-delta modulator has been designed and simulated. Asynchronous sigma-delta modulators eliminate the continuous time sigma-delta modulator's problem of signal-to-noise ratio degradation due to clock jitter by avoiding the use of sampling in the modulator loop. Moreover, they provide a higher signal-to-noise ratio even with low-order filters. Thus, considerably low power consumption can be achieved with fewer circuit components. The current mode enables designers to scale the circuits according to different supply voltages and operating currents. In this work, design steps for an asynchronous sigma-delta modulator have been given taking into account its ideal …
Direct Radio Frequency Sampling Methodology For Multiple Signals In An Energy-Sparse Spectrum,
2016
TÜBİTAK
Direct Radio Frequency Sampling Methodology For Multiple Signals In An Energy-Sparse Spectrum, Tauqeer Ahmed, Noor Muhammad Khan
Turkish Journal of Electrical Engineering and Computer Sciences
In software defined radio (SDR) systems, it is desirable to down-convert multiple RF signals simultaneously by placing an analogue-to-digital converter (ADC) as near the antenna as possible. Radio frequency (RF) subsampling is one of the established methodologies used by radio receivers to directly down-convert and digitize RF signals. In this paper, we propose a novel direct RF sampling method to find out the minimum sampling frequency for an evenly spaced spectrum comprising multiband RF signals. However, it can also be applied to nonuniformly spaced signals with slight modification. The proposed methodology describes a set of rules to achieve the lowest …
Fpga Implementation Of A Hevc Deblocking Filter For Fast Processing Of Super High Resolution Applications,
2016
TÜBİTAK
Fpga Implementation Of A Hevc Deblocking Filter For Fast Processing Of Super High Resolution Applications, Awais Khan, Gulistan Raja
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes the architecture of a deblocking filter (DBF) that removes blocking artifacts in new emerging High Efficiency Video Coding (HEVC). A parallel architecture for both normal and strong filtering modes of HEVC is proposed. Distributed memories and two data paths increase the parallelism and make the architecture more efficient. The proposed architecture is described by Verilog and implemented on FPGA. The architecture can realize real time to compute 4K UHD video at 30 fps by using 46.65 million clocks with total equivalent gate count of 46K. The maximum delay time for output to come after taking input for …
Variation Of Photovoltaic System Performance Due To Climatic And Geographical Conditions In Turkey,
2016
TÜBİTAK
Variation Of Photovoltaic System Performance Due To Climatic And Geographical Conditions In Turkey, Betül Bektaş Eki̇ci̇
Turkish Journal of Electrical Engineering and Computer Sciences
This study focuses on the effect of climatic and geographical factors on the performance of photovoltaic systems. For this purpose, 4 different cities (Antalya, İstanbul, Elazığ, and Erzurum) from different climatic zones according to TS 825 Thermal Insulation Requirements in Buildings were selected. The monthly average global and diffuse solar radiation of the cities was calculated numerically with the long-term sunshine duration data (between 1990 and 2012) taken from the Turkish State Meteorological Service. The yearly electric energy generated by the grid-connected photovoltaic systems assumed to be located on the flat roofs of building samples were calculated for each of …
Sinusoidal Current Injection Based On A Line-Commutated Inverter For Single-Phase Grid-Connected Renewable Energy Sources,
2016
TÜBİTAK
Sinusoidal Current Injection Based On A Line-Commutated Inverter For Single-Phase Grid-Connected Renewable Energy Sources, Murat Ünlü, Sabri̇ Çamur, Ersoy Beşer, Bi̇rol Ari̇foğlu
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new power electronic interface based line-commutated inverter (LCI) for dc power injection to the grid. The proposed system involves a simple power electronic converter and controller interface using a single-phase LCI. The controller has been developed that can inject a high quality sinusoidal current to the utility grid from the dc source. By this means, ac side harmonic filters and the harmonic cancellation technique are eliminated. The proposed system facilitates controlling the injected current with a controllable power factor of operation. The complete system has been modeled in MATLAB/Simulink and tested experimentally with the laboratory prototype. …
A New Method For Active Power Factor Correction Using A Dual-Purpose Inverter In A Flyback Converter,
2016
TÜBİTAK
A New Method For Active Power Factor Correction Using A Dual-Purpose Inverter In A Flyback Converter, Seyed Mohsen Hoseini, Seyed Mohammad Sadeghzadeh, Yousef Alinejad Beromi
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new active method for power factor correction (PFC) is presented and applied to a single-stage AC/DC flyback converter to reduce the total harmonic distortion of the input current, achieve better power factor compensation, and improve converter reliability. The proposed circuit consists of a low-power portable dual-purpose inverter that can work in 2 main modes. In the normal mode of converter operation, the PFC circuit operates as an active harmonic filter compensator. In the second mode, which occurs in converter outage conditions, the inverter behaves as a sinusoidal backup voltage power supply for the converter by using …
Firefly Algorithm With Multiple Workers For The Power System Unit Commitment Problem,
2016
TÜBİTAK
Firefly Algorithm With Multiple Workers For The Power System Unit Commitment Problem, Banumalar Koodalsamy, Manikandan Bairavan Veerayan, Chandrasekaran Koodalsamy, Sishaj Pulikottil Simon
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes an improved firefly (FF) algorithm with multiple workers for solving the unit commitment (UC) problem of power systems. The UC problem is a combinatorial optimization problem that can be posed as minimizing a quadratic objective function under system and unit constraints. Nowadays, highly developed computer systems are available in plenty, and proper utilization of these systems will reduce the time and complexity of combinatorial optimization problems with large numbers of generating units. Here, multiple workers are assigned to solve a UC problem as well as the subproblem, namely economic dispatch (ED) in distributed memory models. The proposed …
A Comparative Analysis Of Wind Speed Probability Distributions For Wind Power Assessment Of Four Sites,
2016
TÜBİTAK
A Comparative Analysis Of Wind Speed Probability Distributions For Wind Power Assessment Of Four Sites, Vaishali Sohoni, Shivcharan Gupta, Rajeshkumar Nema
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, five probability distribution functions are employed to fit the wind speed data from four different geographical locations in the world in a preliminary analysis. These wind regimes are selected such that they represent wide ranges of mean wind speeds and present different shapes of wind speed histograms. The wind speed data used for modelling consist of 10-min average SCADA data from three US wind farms and hourly averages recorded at a weather station in Canada. Out of the five, three functions, namely Weibull, Rayleigh, and gamma, which provide a better fit to the data, are selected to …
Modeling, Control, And Power Management For A Grid-Integrated Photo Voltaic, Fuel Cell, And Wind Hybrid System,
2016
TÜBİTAK
Modeling, Control, And Power Management For A Grid-Integrated Photo Voltaic, Fuel Cell, And Wind Hybrid System, Ezhilarasan Ganesan, Subhranhsu Sekhar Dash, Chinmaya Samanta
Turkish Journal of Electrical Engineering and Computer Sciences
Power management in a grid-integrated power system consisting of distributed renewable energy sources is necessitated by ever-increasing energy consumption, the high cost of production, the limited resource of fossil fuel, and the worsening global environment. Wind and solar power generation are two of the most promising renewable power generation technologies. The growth of wind and photovoltaic (PV) power generation systems has exceeded the most optimistic levels of expectations. Fuel cells (FCs) also have great potential to be green power sources of the future because of the many merits they have, such as high efficiency and zero or low emission of …
Iec 61850-Based Islanding Detection And Load Shedding In Substation Automation Systems,
2016
TÜBİTAK
Iec 61850-Based Islanding Detection And Load Shedding In Substation Automation Systems, Cagil Ozansoy, Keith Frearson
Turkish Journal of Electrical Engineering and Computer Sciences
Distributed generation (DG) systems are common within industrial plants and allow continuity of supply to critical loads. In cases when DG cannot support the entire system load, islanding detection (ID) and load shedding (LS) schemes are required. Such an automation scheme serves to monitor the connection to the grid and generation-load imbalance, and it controls the load shedding process. The design of such schemes has undergone significant revolution from electromechanical relays and PLC systems to the use of communications-enabled intelligent electronic devices. This paper discusses the design of an IEC 61850-based smart ID and LS scheme using a complete system …
Double Bow-Tie Fss For X-Band And K$_U$-Band Operations With Its Parametric Analyses,
2016
TÜBİTAK
Double Bow-Tie Fss For X-Band And K$_U$-Band Operations With Its Parametric Analyses, Selma Çi̇ğdem, Ci̇han Tunca, Sultan Can, Asim Egemen Yilmaz
Turkish Journal of Electrical Engineering and Computer Sciences
This paper demonstrates double bow-tie frequency selective surface (FSS) geometry for X-band applications with a bandwidth value of 1.82 GHz and K$_u$-band applications with a bandwidth value of 3.44 GHz. Throughout this study, parametric analyses of the proposed structure are also performed. Alterations in the reflection and transmission characteristics of this specially designed structure by virtue of defined variables are analyzed. Those variables are determined by considering the geometric and material properties of the proposed structure. To analyze the reflection and transmission coefficients, two different simulators, namely the High Frequency Structure Simulator (ANSYS HFSS), which is based on the finite …
Leveraging Linked Open Data Information Extraction For Data Mining Applications,
2016
TÜBİTAK
Leveraging Linked Open Data Information Extraction For Data Mining Applications, Rajesh Mahule, Om Prakash Vyas
Turkish Journal of Electrical Engineering and Computer Sciences
The linked open data cloud, with a huge volume of data from heterogeneous and interlinked datasets, has turned the Web into a large data store. It has attracted the attention of both developers and researchers in the last few years, opening up new dimensions in machine learning and knowledge discovery. Information extraction procedures for these processes use different approaches, e.g., template-based, federated to multiple sources, fixed depth link traversal, etc. They are limited by problems in online access to datasets' SPARQL endpoints, such as servers being down for maintenance, bandwidth narrowing, limited numbers of access points to datasets in particular …
Applying Metaheuristic Optimization Methods To Design Novel Adaptive Pi-Type Fuzzy Logic Controllers For Load-Frequency Control In A Large-Scale Power Grid, Thimaiphuong Dao, Yaonan Wang, Ngockhoat Nguyen
Turkish Journal of Electrical Engineering and Computer Sciences
Due to the complexity and diversity of large-scale power systems in practice, designing load-frequency control (LFC) strategies against load variations faces big challenges to ensure the stability and economy of the network. The focus of this paper is to design a novel adaptive PI-type fuzzy logic (FL)-based LFC architecture for solving the LFC problem in such an interconnected electric power grid. Applying 2 biologically inspired optimization methods, namely particle swarm optimization method and a genetic algorithm, the membership functions and rule base of a basic PI-type FL model were parameterized and optimized simultaneously and successfully. An online self-tuning method was …
Speech Recognition Using Ann And Predator-Influenced Civilized Swarm Optimization Algorithm,
2016
TÜBİTAK
Speech Recognition Using Ann And Predator-Influenced Civilized Swarm Optimization Algorithm, Teena Mittal, Rajendra Kumar Sharma
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a hybrid optimization technique, predator-influenced civilized swarm optimization, by integrating civilized swarm optimization (CSO) and predator-prey optimization (PPO) techniques. CSO is the integration of the attributes of particle swarm optimization and a society civilization algorithm (SCA). In the SCA, the swarm is divided into a few societies, and each society has its own society leader (SL); other individuals of the society are termed society members. The combination of all such societies forms a civilization, and the best-performing SL becomes the civilization leader (CL). In CSO, SLs and members update their positions through the guidance of their own …
Balancing Exploration And Exploitation By Using Sequential Execution Cooperation Between Artificial Bee Colony And Migrating Birds Optimization Algorithms, Hasan Makas, Nejat Yumuşak
Turkish Journal of Electrical Engineering and Computer Sciences
The artificial bee colony (ABC) algorithm is a metaheuristic search method inspired by bees' foraging behaviour. With its global search ability in scout bee phase, it can easily escape from local optimum traps in the problem space. Therefore, it is good at exploration. The migrating birds optimization (MBO) algorithm is another recent metaheuristic search method. It simulates birds' V flight formation, which minimizes energy consumption during flight. The MBO algorithm achieves a good convergence to the global optimum by using its own unique benefit mechanism. That is, it has a good exploitation capability. This paper aimed to combine the good …
A Second-Order Volterra Filter-Based Nonlinear Clipping Detector,
2016
TÜBİTAK
A Second-Order Volterra Filter-Based Nonlinear Clipping Detector, Jihwan Park, Joon-Hyuk Chang
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we propose a novel nonlinear clipping detector based on the second-order Volterra filter for an acoustic echo canceller (AEC). Since the performance of the conventional AEC algorithm drastically deteriorates when nonlinear clipping occurs, the adaptive filter pauses adaptation during the nonlinear clipping periods to avoid unwanted divergence. These nonlinear clipping periods are detected in our method using the magnitude spectrum of the quadratic Volterra filter in lower frequency ranges. Through extensive computer-based simulation results considering an acoustic room environment and various clipping levels, it is found that the proposed approach is effective in detecting the nonlinear clipping …
Low Leakage Power Gating Technique For Subnanometer Cmos Circuits,
2016
TÜBİTAK
Low Leakage Power Gating Technique For Subnanometer Cmos Circuits, Kavitha Manickam, Govindaraj Thangavel
Turkish Journal of Electrical Engineering and Computer Sciences
Static power has become the most important factor in the fabrication of integrated circuits. Power gating techniques minimize leakage currents and help to develop ultra-low-power and high-performance digital circuits. In this paper, a power gating approach is proposed to minimize leakage for subnanometer technologies. Simulation results reveal that the proposed technique reduces maximum of 96% leakage power, 33% dynamic power, 49% drowsy power, and 16{\%} energy as compared to conventional techniques. The proposed technique offers good leakage reduction, even under variation of different operating parameters.
Multilayer Authorization Model And Analysis Of Authorization Methods,
2016
TÜBİTAK
Multilayer Authorization Model And Analysis Of Authorization Methods, Alper Uğur, İbrahi̇m Soğukpinar
Turkish Journal of Electrical Engineering and Computer Sciences
There are various methods proposed in the literature to provide authorization control in workflows and information systems. Authorization implementations have deficiencies based on procedural scope. Basic login mechanisms grant system-wide access; the provided margins are broad. Access control lists provide limited definition on access restrictions; the authorization is bounded by these definitions. Role based authorizations do not cover regulations in institutions where the regulations describe specific operations and their operational procedures in institutional workflows. The proposed multilayer authorization model depicts the attributes of authorization mechanisms and analyzes the methods according to their authorization capabilities and contributions to the reliability of …
Interference In Geoelectric Field Observation From The Current Of A Direct-Current Grounding Electrode,
2016
TÜBİTAK
Interference In Geoelectric Field Observation From The Current Of A Direct-Current Grounding Electrode, Bo Tang, Zhuo Wu, Ren Liu, Shuang Wang, Qixiang Lin
Turkish Journal of Electrical Engineering and Computer Sciences
The existence of ultrahigh voltage direct-current (UHVDC) transmission lines impacts geoelectric field observation (GFO), which further disturbs earthquake observation and prediction. We proposed a mathematic method based on a 3-dimensional layered soil model to calculate the interference and conducted GFO experiments at observatories and field observation sites during the live debugging of a $\pm $800 kV UHVDC transmission line to verify the method. The results obtained by using the proposed method are in good accordance with the experimental results and the maximum error is no more than 15%. Moreover, the experiment proves that grounding current is a decisive factor in …
