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Engineering

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2016

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Articles 511 - 529 of 529

Full-Text Articles in Physical Sciences and Mathematics

Novel Dynamic Partial Reconfiguration Implementations Of The Support Vector Machine Classifier On Fpga, Hanaa Hussain, Khaled Benkrid, Hüseyi̇n Şeker Jan 2016

Novel Dynamic Partial Reconfiguration Implementations Of The Support Vector Machine Classifier On Fpga, Hanaa Hussain, Khaled Benkrid, Hüseyi̇n Şeker

Turkish Journal of Electrical Engineering and Computer Sciences

The support vector machine (SVM) is one of the highly powerful classifiers that have been shown to be capable of dealing with high-dimensional data. However, its complexity increases requirements of computational power. Recent technologies including the postgenome data of high-dimensional nature add further complexity to the construction of SVM classifiers. In order to overcome this problem, hardware implementations of the SVM classifier have been proposed to benefit from parallelism to accelerate the SVM. On the other hand, those implementations offer limited flexibility in terms of changing parameters and require the reconfiguration of the whole device. The latter interrupts the operation …

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Experimental Characterization Of Wafer Probe Burn, Baha Zafer, Bahadir Tunaboylu Jan 2016

Experimental Characterization Of Wafer Probe Burn, Baha Zafer, Bahadir Tunaboylu

Turkish Journal of Electrical Engineering and Computer Sciences

The probing test is a typical quality control method for individual chips on a wafer. This study investigates the cantilever wafer probe current carrying capacity along a probe body in order to model the probe burn phenomenon by using experimental techniques and numerical simulation. The standard measurement approach used in the test industry is conducted to define the mechanical degradation of the cantilever probe on the wafer card and temperature distribution along the probe body is conducted using a conduction heat transfer equation via computational discretization. Maximum current carrying capacity is defined and the probe burn phenomenon is observed at …

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Stability Criterion For Uncertain 2-$D$ Discrete Systems With Interval-Like Time-Varying Delay Employing Quantization/Overflow Nonlinearities, Siva Kumar Tadepalli, Venkata Krishna Rao Kandanvli, Haranath Kar Jan 2016

Stability Criterion For Uncertain 2-$D$ Discrete Systems With Interval-Like Time-Varying Delay Employing Quantization/Overflow Nonlinearities, Siva Kumar Tadepalli, Venkata Krishna Rao Kandanvli, Haranath Kar

Turkish Journal of Electrical Engineering and Computer Sciences

This paper considers the problem of global asymptotic stability of a class of two-dimensional (2-$D$) uncertain discrete systems described by the Fornasini-Marchesini second local state-space (FMSLSS) model under the influence of various combinations of quantization/overflow nonlinearities and interval-like time-varying delay in the state. The systems under consideration involve parameter uncertainties that are assumed to be deterministic and norm-bounded. A delay-dependent stability criterion is established by bounding the forward difference of the 2-$D$ Lyapunov functional using the reciprocally convex approach. The criterion is compared with a recently reported criterion.

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A Current Feedback Control Strategy For Parallel-Connected Single-Phase Inverters Using A Third-Order General-Integrator Crossover Cancellation Method, Yuan Huang, An Luo Jan 2016

A Current Feedback Control Strategy For Parallel-Connected Single-Phase Inverters Using A Third-Order General-Integrator Crossover Cancellation Method, Yuan Huang, An Luo

Turkish Journal of Electrical Engineering and Computer Sciences

Virtual impedance is usually introduced to the control system of parallel inverters in order to change the inverter equivalent output impedance and to enhance control accuracy and power sharing. In this paper, a current feedback control strategy using a third-order general-integrator crossover-cancellation method that can be implemented in a virtual impedance loop is proposed. This method consists of 2 parts: a crossover-cancellation feedback network, which achieves the band-pass effect, and a multilevel TOGI-OSG link, which acts as a filter. Compared with the conventional virtual impedance method, the proposed method can avoid derivation of output current, reduce system calculating burden, and …

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Statistical Learning Approaches In Diagnosing Patients With Nontraumatic Acute Abdomen, Gökmen Zararsiz, Hizir Yakup Akyildiz, Di̇nçer Göksülük, Selçuk Korkmaz, Ahmet Öztürk Jan 2016

Statistical Learning Approaches In Diagnosing Patients With Nontraumatic Acute Abdomen, Gökmen Zararsiz, Hizir Yakup Akyildiz, Di̇nçer Göksülük, Selçuk Korkmaz, Ahmet Öztürk

Turkish Journal of Electrical Engineering and Computer Sciences

A quick evaluation is required for patients with acute abdominal pain. It is crucial to differentiate between surgical and nonsurgical pathology. Practical and accurate tests are essential in this differentiation. Lately, D-dimer level has been found to be an important adjuvant in this diagnosis and obviously outperforms leukocyte count, which is widely used for diagnosis of certain cases. Here, we handle this problem from a statistical perspective and combine the information from leukocyte count with D-dimer level to increase the diagnostic accuracy of nontraumatic acute abdomen. For this purpose, various statistical learning algorithms are considered and model performances are assessed …

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Adaptive Speed Observer With Disturbance Torque Compensation For Sensorless Induction Motor Drives Using Rt-Lab, Mohan Krishna, Febin Daya Jan 2016

Adaptive Speed Observer With Disturbance Torque Compensation For Sensorless Induction Motor Drives Using Rt-Lab, Mohan Krishna, Febin Daya

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an improved version of the extended Luenberger observer with joint estimation of rotor speed and disturbance torque. The mechanical model of the induction motor is also utilized for the estimation of disturbance torque to add to the robustness of the observer. The estimated disturbance torque is treated as a model disturbance and physically incorporated into the observer state dynamic equation. The dynamic performance and efficacy of the modified observer is tested for variations in external load and inertia coefficient in the mechanical model. The above observer model is first built offline, using MATLAB/Simulink block sets, and simulated. …

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A Multiobjective Tuning Approach Of Power System Stabilizers Using Particle Swarm Optimization, Hilal Labdelaoui, Fares Boudjema, Djamel Boukhetala Jan 2016

A Multiobjective Tuning Approach Of Power System Stabilizers Using Particle Swarm Optimization, Hilal Labdelaoui, Fares Boudjema, Djamel Boukhetala

Turkish Journal of Electrical Engineering and Computer Sciences

This work presents an optimal tuning approach of power system stabilizers (PSSs) using multiobjective particle swarm optimization. Two types of PSSs are investigated, the conventional speed-based PSS type and a dual-input PSS type that uses the accelerating power as an additional input. The tuning problem of these PSSs is formulated as a minimization problem of a vector objective function characterizing the damping and the transient performance of the closed-loop system. A 3-machine 9-bus power system example is considered, and the speed-constrained multiobjective particle swarm optimization algorithm is used to solve the optimization problem. The results show that trade-offs exist between …

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Selective Harmonics Elimination Pwm With Self-Balancing Dc-Link In Photovoltaic 7-Level Inverter, Khoukha Imarazene, Hachemi Chekireb, El Madjid Berkouk Jan 2016

Selective Harmonics Elimination Pwm With Self-Balancing Dc-Link In Photovoltaic 7-Level Inverter, Khoukha Imarazene, Hachemi Chekireb, El Madjid Berkouk

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new DC-link balancing method for a 7-level inverter fed by a photovoltaic system is proposed. The proposed redundant state technique is associated with selective harmonics elimination (SHE)-PWM instead of space vector (SV)-PWM. The switching angles related to the SHE are computed via the resultant theory method. Moreover, the study of this inverter is carried out on its equivalent matrix model. On the basis of this model, the link between the capacitor voltage, switching states, and load current is established. This allows understanding the switching redundancies' effect on the DC capacitor voltage balance. An algorithm is then …

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Fuzzy Based Design Of Digital Iir Filter Using Etlbo, Damanpreet Singh, Jaspreet Singh Dhillon Jan 2016

Fuzzy Based Design Of Digital Iir Filter Using Etlbo, Damanpreet Singh, Jaspreet Singh Dhillon

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a population-based robust enhanced teaching--learning-based optimization (ETLBO) algorithm with reduced computational effort and high consistency is applied to design stable digital infinite-impulse response (IIR) filters in a multiobjective framework. Furthermore, a decision-making methodology based on fuzzy set theory is applied to handle nonlinear and multimodal design problems of the IIR digital filter. The original teaching--learning-based optimization (TLBO) algorithm has been remodeled by merging the concepts of opposition-based learning and migration for the selection of good candidates and to maintain diversity, respectively. A multiobjective IIR digital filter design problem takes into consideration magnitude and phase response of the …

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Energy-Aware Stochastic Scheduling Model With Precedence Constraints On Dvfs-Enabled Processors, Mohammad Sajid, Zahid Raza Jan 2016

Energy-Aware Stochastic Scheduling Model With Precedence Constraints On Dvfs-Enabled Processors, Mohammad Sajid, Zahid Raza

Turkish Journal of Electrical Engineering and Computer Sciences

The stochastic scheduling of precedence-constrained jobs on a heterogeneous processor is a challenging problem that requires solutions with one or more optimized QoS parameters. In this work, an energy-aware stochastic algorithm is proposed to schedule the batch of precedence-constrained jobs on heterogeneous DVFS-enabled processors with the objective of optimizing turnaround time and energy consumption. The processing time of tasks in all jobs and their precedence-constraint times are governed by independent probability distributions. The performance of the proposed stochastic algorithm is compared with SHEFT and ECS based on randomly generated batches of different sizes. The experimental study reveals that the proposed …

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High Photoresponse From Solution Processed Conventional And Inverted Ultraviolet Photodetectors, Görkem Memi̇şoğlu, Canan Varlikli Jan 2016

High Photoresponse From Solution Processed Conventional And Inverted Ultraviolet Photodetectors, Görkem Memi̇şoğlu, Canan Varlikli

Turkish Journal of Electrical Engineering and Computer Sciences

The optical and electrical properties of conventional and inverted type ultraviolet photodetectors (UVPDs) with active layers of poly(9,9-dioctylfluorenyl-2,7-ylenethynylene (PFE), $N$,$N'$-bis-$n$-butyl-1,4,5,8-naphthalenediimide (BNDI), and zincoxide (ZnO) are introduced. Optimized devices showed high photoresponse, external quantum efficiency (EQE), and detectivity (D*) values. Under 365 nm 1 mW/cm$^{2}$, the conventional device (ITO/PEDOT:PSS/[(PFE:BNDI) (3:1):8 wt% ZnO]/Al) and the inverted device (ITO/[(PFE:BNDI)(3:1):8 wt% ZnO]/Au) gave photoresponsivities of 515 mA/W and 316 mA/W, D* of 1.12 $\times$ 10$^{14 }$Jones and 0.71 $\times$ 10$^{14 }$Jones, and EQE of 174% and 107%, respectively. Annealing the devices at polymer's glass transition temperature (T$_{g}$ 60 $^{\circ}$ C), enhanced these values to …

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A Switching Inverse Dynamics Controller For Parallel Manipulators Around Drive Singular Configurations, Mustafa Özdemi̇r, Sitki Kemal İder Jan 2016

A Switching Inverse Dynamics Controller For Parallel Manipulators Around Drive Singular Configurations, Mustafa Özdemi̇r, Sitki Kemal İder

Turkish Journal of Electrical Engineering and Computer Sciences

Despite many advantages, parallel manipulators are known to possess drive singularities where the control of one or more degrees of freedom is lost. Around these singular configurations, the required actuator forces grow unbounded. Previous efforts in the literature put forward singularity-consistent trajectory planning and singularity-robust modification of the dynamic equations as a solution to this problem. However, this previous method is applicable only for the open-loop operation of the manipulator, whereas initial configuration errors, external disturbances, and modeling errors should necessarily be taken into account in a closed-loop sense in real-life applications. With this aim, a switching inverse dynamics controller …

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An Attribute Or Tuple Timestamping In Bitemporal Relational Databases, Canan Atay Jan 2016

An Attribute Or Tuple Timestamping In Bitemporal Relational Databases, Canan Atay

Turkish Journal of Electrical Engineering and Computer Sciences

Much of the research on bitemporal databases has focused on the modeling of time-related data with either attribute or tuple timestamping. While the attribute-timestamping approach attaches bitemporal data to attributes, the tuple-timestamping approach splits the object's history into several tuples. Although there have been numerous studies on bitemporal data models, there is no work contrasting these two common approaches in terms of system performance and ease of use. In this paper, we compared interval-based attribute- and tuple-timestamped bitemporal data models by running sample queries to measure processing time, and then we evaluated their usability by using the same data. Our …

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Computer-Assisted Cobb Angle Measurement From Posteroanterior Radiographs By A Curve Fitting Method, İbrahi̇m Yildiz Jan 2016

Computer-Assisted Cobb Angle Measurement From Posteroanterior Radiographs By A Curve Fitting Method, İbrahi̇m Yildiz

Turkish Journal of Electrical Engineering and Computer Sciences

Incorrect determination of the top or end vertebrae of a scoliotic curve causes measurement errors when using the Cobb method. Such problems are due to subjectivity. This study was performed to minimize subjectivity by using a curve fitting method. A digitally scanned posteroanterior radiographic image was used for each patient. User-defined midpoints of the curvature, which indicate the midpoints of the vertebrae, were used to fit the polynomial equation. The locations of the top and end vertebrae were calculated using the first derivative of the fitted polynomial equation to obtain the analytical Cobb angle. The interobserver technical error of measurements …

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Direct Radio Frequency Sampling Methodology For Multiple Signals In An Energy-Sparse Spectrum, Tauqeer Ahmed, Noor Muhammad Khan Jan 2016

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 …

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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 Jan 2016

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. …

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An Interval-Based Contingency Selection Approach Considering Uncertainty, Chao Xu, Wei Gu, Lizi Luo, Jianguo Yao, Shengchun Yang, Ke Wang, Dan Zeng, Miao Fan Jan 2016

An Interval-Based Contingency Selection Approach Considering Uncertainty, Chao Xu, Wei Gu, Lizi Luo, Jianguo Yao, Shengchun Yang, Ke Wang, Dan Zeng, Miao Fan

Turkish Journal of Electrical Engineering and Computer Sciences

Static security assessment is affected by uncertainties of load flow distributions introduced by renewable sources. A fast contingency selection approach based on interval theory is proposed in this paper. Firstly, an interval line active flow calculation algorithm is developed to reduce conservation in application of interval mathematics in line flow calculation. Then a novel interval comparison method based on Bayesian probability theory is applied in interval index comparison to give the relative severity information of contingencies. Finally, an approximately consistent ranking method is utilized in contingency ranking to rank screened contingencies. Numerical studies on several IEEE standard test systems and …

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Iec 61850-Based Islanding Detection And Load Shedding In Substation Automation Systems, Cagil Ozansoy, Keith Frearson Jan 2016

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 …

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Design Of A Fuzzy Logic Controlled Thermoelectric Brain Hypothermia System, Abdullah Hakan Yavuz Jan 2016

Design Of A Fuzzy Logic Controlled Thermoelectric Brain Hypothermia System, Abdullah Hakan Yavuz

Turkish Journal of Electrical Engineering and Computer Sciences

Brain cooling in medicine is the most effective method in protecting brain cells during strokes, heart attacks, and brain traumas. This method, called brain hypothermia, is based on the principle that the brain is superficially cooled under controlled conditions in order to minimize cell death. In this study a helmet was designed to locally cool the brain and an effective controller was designed and tested using fuzzy logic in order to test the effectiveness of the helmet for brain hypothermia. For testing the cooling and heating performances of the helmet, currents between 0 and 60 A were applied to the …

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