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Articles 4681 - 4710 of 7215

Full-Text Articles in Computer Engineering

Tunable Absorption Based On Plasmonic Nanostructures Loaded With Graphene, Christos Argyropoulos Jan 2015

Tunable Absorption Based On Plasmonic Nanostructures Loaded With Graphene, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

We present simulations of a hybrid graphene-plasmonic device constituted by periodic metallic nanowires placed over a dielectric spacer layer and a metallic film. The spacer layer is composed of a thin silica layer combined with an one-atom-thick graphene sheet. An electrically controlled ultra-compact absorption modulator can be realized based on the proposed theoretical device.

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Robust Optimization For Bidirectional Dispatch Coordination Of Large-Scale V2g, Xiaoqing Bai, Wei Qiao Jan 2015

Robust Optimization For Bidirectional Dispatch Coordination Of Large-Scale V2g, Xiaoqing Bai, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a robust optimization (RO) model for bidirectional dispatch coordination of large-scale plugin electric vehicles (PEVs) in a power grid in which the PEVs are aggregated to manage. The PEV aggregators are considered as a type of dispatchable demand response and energy storage resource with stochastic behaviors, and can supply load or provide ancillary services such as regulation reserve to the grid. The proposed RO model is then reformulated as a mixedinteger quadratic programming model, which can be solved efficiently. Computer simulations are performed for a power grid with ten generators and three PEV aggregators to validate the …

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Optimal Bidding Strategy Of A Strategic Wind Power Producer In The Short-Term Market, Ting Dai, Wei Qiao Jan 2015

Optimal Bidding Strategy Of A Strategic Wind Power Producer In The Short-Term Market, Ting Dai, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Wind energy is a clean and renewable energy source which is rapidly growing globally. As the penetration level of wind power grows, the system operators need to consider wind power producers as strategic producers whose bidding behaviors will have an impact on the locational marginal prices. This paper proposes a bilevel stochastic optimization model to obtain the optimal bidding strategy for a strategic wind power producer in the short-term electricity market. The upper level problem of the model maximizes the profit of the wind power producer, while the lower level problem represents the market clearing processes of both day-ahead and …

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Multiobjective Optimization Of Switched Reluctance Motors Based On Design Of Experiments And Particle Swarm Optimization, Cong Ma, Liyan Qu Jan 2015

Multiobjective Optimization Of Switched Reluctance Motors Based On Design Of Experiments And Particle Swarm Optimization, Cong Ma, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a comprehensive framework for multiobjective design optimization of switched reluctance motors (SRMs) based on a combination of the design of experiments and particle swarm optimization (PSO) approaches. First, the definitive screening design was employed to perform sensitivity analyses to identify significant design variables without bias of interaction effects between design variables. Next, optimal third-order response surface (RS) models were constructed based on the Audze–Eglais Latin hypercube design using the selected significant design variables. The constructed optimal RS models consist of only significant regression terms, which were selected by using PSO. Then, a PSO-based multiobjective optimization coupled with …

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A Survey On Wind Turbine Condition Monitoring And Fault Diagnosis−Part I: Components And Subsystems, Deli Qiao, Dingguo Lu Jan 2015

A Survey On Wind Turbine Condition Monitoring And Fault Diagnosis−Part I: Components And Subsystems, Deli Qiao, Dingguo Lu

Department of Electrical and Computer Engineering: Faculty Publications

This paper provides a comprehensive survey on the state-of-the-art condition monitoring and fault diagnostic technologies for wind turbines. The Part I of this survey briefly reviews the existing literature surveys on the subject, discusses the common failure modes in the major wind turbine components and subsystems, briefly reviews the condition monitoring and fault diagnostic techniques for these components and subsystems, and specifically discusses the issues of condition monitoring and fault diagnosis for offshore wind turbines.

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A Survey On Wind Turbine Condition Monitoring And Fault Diagnosis−Part Ii: Signals And Signal Processing Methods, Wei Qiao, Dingguo Lu Jan 2015

A Survey On Wind Turbine Condition Monitoring And Fault Diagnosis−Part Ii: Signals And Signal Processing Methods, Wei Qiao, Dingguo Lu

Department of Electrical and Computer Engineering: Faculty Publications

This paper provides a comprehensive survey on the state-of-the-art condition monitoring and fault diagnostic technologies for wind turbines. The Part II of this survey focuses on the signals and signal processing methods used for wind turbine condition monitoring and fault diagnosis.

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A Real-Time Information Based Demand-Side Management System In Smart Grid, Feng Ye, Yi Qian, Rose Qingyang Hu Jan 2015

A Real-Time Information Based Demand-Side Management System In Smart Grid, Feng Ye, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, we study a real-time information based demand-side management (DSM) system with advanced communication networks in smart grid. DSM can smooth peakto- average ratio (PAR) of power usage in the grid, which in turn reduces the waste of fuel and the emission of greenhouse gas. We first target to minimize PAR with a centralized scheme. To motivate power suppliers, we further propose another centralized scheme targeting minimum power generation cost. However, customers may not be motivated by a centralized scheme since such a scheme requires total control and privacy from them. A centralized scheme also requires too much …

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An Isolated Three-Port Bidirectional Dc-Dc Converter For Photovoltaic Systems With Energy Storage, Jianwu Zeng, Wei Qiao, Liyan Qu Jan 2015

An Isolated Three-Port Bidirectional Dc-Dc Converter For Photovoltaic Systems With Energy Storage, Jianwu Zeng, Wei Qiao, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

This paper proposes a new isolated, three-port, bidirectional, DC-DC converter for simultaneous power management of multiple energy sources. The proposed converter has the advantage of using the least number of switches and soft switching for the main switch, which is realized by using a LCL-resonant circuit. The converter is capable of interfacing sources of different voltage-current characteristics with a load and/or a DC microgrid. The proposed converter is constructed for simultaneous power management of a photovoltaic (PV) panel, a rechargeable battery, and a load. Simulation and experimental results show that the proposed converter is capable of maximum power point tracking …

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Modeling And Control Of A Three-Port Dc-Dc Converter For Pv-Battery Systems, Jianwu Zeng, Wei Qiao, Liyan Qu Jan 2015

Modeling And Control Of A Three-Port Dc-Dc Converter For Pv-Battery Systems, Jianwu Zeng, Wei Qiao, Liyan Qu

Department of Electrical and Computer Engineering: Faculty Publications

This paper presents modeling and decoupled control design for an isolated three-port DC-DC converter (TPC), which interfaces a photovoltaic (PV) panel, a rechargeable battery, and an isolated load. A small signal model is derived from the state-space equations of the TPC. Based on the model, two decoupled controllers are designed to control the power flows of the two sources and the load voltage independently. Experimental studies are performed to verify that the two controllers are capable of regulating the power flows of the PV panel and the battery while maintaining a constant output voltage for the TPC.

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Optimal Joint Transmission And Harvested Energy Scheduling For Renewable Energy Harvesting Enabled Cellular Network Under Coordinated Multi-Point Transmission, Zejue Wang, Hongjia Li, Dan Hu, Song Ci Jan 2015

Optimal Joint Transmission And Harvested Energy Scheduling For Renewable Energy Harvesting Enabled Cellular Network Under Coordinated Multi-Point Transmission, Zejue Wang, Hongjia Li, Dan Hu, Song Ci

Department of Electrical and Computer Engineering: Faculty Publications

On-grid energy consumption of base stations (BSs) contributes up a significant fraction of the total carbon dioxide (CO2) emissions of cellular networks, among which remote radio units (RRUs) absorb most of the energy consumption. To eliminate the on-grid energy consumption and the corresponding CO2 emission, we propose a new transmission framework, in which all RRUs and associated power amplifiers (PAs) are powered by hybrid energy sources including on-grid energy source and off-grid renewable energy source. Based on the framework, we pursue a systematic study on the joint transmission and harvested energy scheduling algorithm for the hybrid energy …

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Cmi Analysis And Precoding Designs For Correlated Multi-Hop Mimo Channels, Nguyen N. Tran, Song Ci, Ha X. Nguyen Jan 2015

Cmi Analysis And Precoding Designs For Correlated Multi-Hop Mimo Channels, Nguyen N. Tran, Song Ci, Ha X. Nguyen

Department of Electrical and Computer Engineering: Faculty Publications

Conditional mutual information (CMI) analysis and precoding design for generally correlated wireless multi-hop multi-input multi-output (MIMO) channels are presented in this paper. Although some particular scenarios have been examined in existing publications, this paper investigates a generally correlated transmission system having spatially correlated channel, mutually correlated source symbols, and additive colored Gaussian noise (ACGN). First, without precoding techniques, we derive the optimized source symbol covariances upon mutual information maximization. Secondly, we apply a precoding technique and then design the precoder in two cases: maximizing the mutual information and minimizing the detection error. Since the optimal design for the end-to-end system …

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Integral Equation Analysis Of Em Scattering From Multilayered Metallic Photonic Crystal Accelerated With Adaptive Cross Approximation, Jianxun Su, Zengrui Li, Xujin Yuan, Yaoqing (Lamar) Yang, Junhong Wang Jan 2015

Integral Equation Analysis Of Em Scattering From Multilayered Metallic Photonic Crystal Accelerated With Adaptive Cross Approximation, Jianxun Su, Zengrui Li, Xujin Yuan, Yaoqing (Lamar) Yang, Junhong Wang

Department of Electrical and Computer Engineering: Faculty Publications

A space-domain integral equation method accelerated with adaptive cross approximation (ACA) is presented for the fast and accurate analysis of electromagnetic (EM) scattering from multilayered metallic photonic crystal (MPC). The method directly solves for the electric field in order to easily enable the periodic boundary condition (PBC) in the spatial domain. The ACA is a purely algebraic method allowing the compression of fully populated matrices; hence, its formulation and implementation are independent of integral equation kernel (Green’s function).Therefore, the ACA is very well suited for accelerating integral equation analysis of periodic structure with the integral kernel of the periodic Green’s …

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Drive Systems Including Sliding Mode Observers And Methods Of Controlling The Same, Long Wu, Yue Zhao, Wei Qiao Jan 2015

Drive Systems Including Sliding Mode Observers And Methods Of Controlling The Same, Long Wu, Yue Zhao, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

At least one example embodiment discloses a drive system including a motor including a rotor, the motor configured to receive a measured current, a controller configured to generate a Voltage command for the motor, a sliding mode observer configured to determine an estimated current for the motor based on the Voltage command, determine a difference between the measured current and the estimated current, and determine a Switching control vector and an estimator con figured to estimate a rotor position based on the Switching control vector, the Switching control vector being determined based on the difference and adaptive parameters of the …

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Probes For Multidimensional Nanospectroscopic Imaging And Methods Of Fabrication Thereof, Alexander Weber-Bargionii, Stefano Cabrini, Wei Bao, Mauro Melli, Eli Yablonovitch, Peter J. Schuck Jan 2015

Probes For Multidimensional Nanospectroscopic Imaging And Methods Of Fabrication Thereof, Alexander Weber-Bargionii, Stefano Cabrini, Wei Bao, Mauro Melli, Eli Yablonovitch, Peter J. Schuck

Department of Electrical and Computer Engineering: Faculty Publications

This disclosure provides systems, methods, and apparatus related to probes for multidimenisonal nanospectroscopic imaging. In one aspect, a method includes providing a transparent tip comprising a dielectric material. A four-sided pyramidal-shaped structure is formed at an apex of the transparent tip using a focus ion beam. Metal layers are deposited over two opposing sides of the four-sided pyramidal-shaped structure.

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Using Robots As Therapeutic Agents To Teach Children With Autism Recognize Facial Expression, Seyedmohammad Mavadati, Huanghao Feng, Peyten B. Sanger, S. Silver, Anibal Gutierrez, Mohammad H. Mahoor Jan 2015

Using Robots As Therapeutic Agents To Teach Children With Autism Recognize Facial Expression, Seyedmohammad Mavadati, Huanghao Feng, Peyten B. Sanger, S. Silver, Anibal Gutierrez, Mohammad H. Mahoor

Electrical and Computer Engineering: Graduate Student Scholarship

Background: Recognizing and mimicking facial expressions are important cues for building great rapport and relationship in human-human communication. Individuals with Autism Spectrum Disorder (ASD) have often deficits in recognizing and mimicking social cues, such as facial expressions. In the last decade several studies have shown that individuals with ASD have superior engagement toward objects and particularly robots (i.e. humanoid and non-humanoid). However, majority of the studies have focused on investigating robot’s appearances and the engineering design concepts and very few research have been done on the effectiveness of robots in therapeutic and treatment applications. In fact, the critical question that …

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Mras-Based Sensorless Speed Backstepping Control For Induction Machine, Using A Flux Sliding Mode Observer, Mohamed Moutchou, Ahmed Abbou, Hassan Mahmoudi Jan 2015

Mras-Based Sensorless Speed Backstepping Control For Induction Machine, Using A Flux Sliding Mode Observer, Mohamed Moutchou, Ahmed Abbou, Hassan Mahmoudi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an induction machine rotor speed and rotor flux control using a sensorless backstepping control scheme is discussed. The most interesting point of this technique is that it deals with the nonlinearity of a high-order system by using the virtual control variable to make this system simple, and thus the control outputs can be derived step by step through appropriate Lyapunov functions. To avoid the use of a mechanical sensor, the rotor speed estimation is made by an observer using the model reference adaptive system (MRAS) technique; in order to estimate rotor flux, a sliding mode observer is …

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Designing And Implementing A Reliable Thermal Monitoring System Based On The 1-Wire Protocol On Fpga For A Leo Satellite, Reza Omidi Gosheblagh, Karim Mohammadi Jan 2015

Designing And Implementing A Reliable Thermal Monitoring System Based On The 1-Wire Protocol On Fpga For A Leo Satellite, Reza Omidi Gosheblagh, Karim Mohammadi

Turkish Journal of Electrical Engineering and Computer Sciences

Thermal control and monitoring is one of the most important factors in the design of satellite systems. An appropriate thermal design should make sure that the satellite's sensitive components remain in their nominated range, even under the vacuum condition of outer space. To achieve this purpose, a reliable and stable monitoring system is required. This paper proposes a monitoring system based on the 1-wire protocol, which provides the reliability requirements in the sensor networking and bus controller sections. In the networking section, we outline some practical topologies and discuss on their complexity and reliability. Despite the fact that the point-to-point …

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Temporal Logic Extension For Self-Referring, Nonexistence, Multiple Recurrence, And Anterior Past Events, Şadi̇ Evren Şeker Jan 2015

Temporal Logic Extension For Self-Referring, Nonexistence, Multiple Recurrence, And Anterior Past Events, Şadi̇ Evren Şeker

Turkish Journal of Electrical Engineering and Computer Sciences

This study focuses on the possible extensions of current temporal logics. In this study, 4 extensions are proposed: self-referring events, nonexisting events, multiple recurrence of events, and an improvement on anterior past events. Each of these extensions is on a different level of temporal logics. The main motivation behind the extensions is the temporal analysis of Turkish. Similar to temporal logic studies built on other natural languages, like French, Ukrainian, Italian, Korean, English, or Romanian, this is the first time that the Turkish language has been deeply questioned in the sense of computable temporal logic using the view of a …

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Discrete-Time Modeling Of Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer, Salman Kurtulan Jan 2015

Discrete-Time Modeling Of Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer, Salman Kurtulan

Turkish Journal of Electrical Engineering and Computer Sciences

The problem of discrete-time modeling of the lumped-parameter Hamiltonian systems is considered for engineering applications. Hence, a novel gradient-based method is presented, exploiting the discrete gradient concept and the forward Euler discretization under the assumption of the continuous Hamiltonian model is known. It is proven that the proposed discrete-time model structure defines a symplectic difference system and has the energy-conserving property under some conditions. In order to provide alternate discrete-time models, 3 different discrete-gradient definitions are given. The proposed models are convenient for the design of sampled-data controllers. All of the models are considered for several well-known Hamiltonian systems and …

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Mersenne Twister-Based Rfid Authentication Protocol, Mehmet Hi̇lal Özcanhan, Gökhan Dalkiliç Jan 2015

Mersenne Twister-Based Rfid Authentication Protocol, Mehmet Hi̇lal Özcanhan, Gökhan Dalkiliç

Turkish Journal of Electrical Engineering and Computer Sciences

This work presents an ultra-lightweight, cryptographic, mutual authentication protocol for radio-frequency identification (RFID) tags. The proposed scheme is more secure than its predecessors. The vulnerabilities of previous schemes based on triangular functions and rotation have been demonstrated in traditional and rotational cryptanalysis. In this paper, we summarize the successful attacks on previous schemes and demonstrate further attacks on 3 recent ultra-lightweight protocols. Next, we present a proposal that resists all of the known passive attacks. The proposal obeys the properties and rules of addition-rotation-XOR with constants systems. The proposed scheme inserts parts of advanced encryption standard S-boxes into the temperings …

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Bandwidth Extension Of Narrowband Speech In Log Spectra Domain Using Neural Network, Sara Pourmohammadi, Mansour Vali, Mohsen Ghadyani Jan 2015

Bandwidth Extension Of Narrowband Speech In Log Spectra Domain Using Neural Network, Sara Pourmohammadi, Mansour Vali, Mohsen Ghadyani

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, there have been significant advances in communication technology, but speech signals still suffer from low perceived quality caused by bandwidth limitations of telephone networks. The bandwidth extension (BWE) approach adds high-frequency components of the speech signal to band-limited telephone speech and increases speech perception significantly. In this work, we develop a new method for representation of vocal tract filter coefficients using log of filter bank energy (LFBE) parameters as an alternative for mel-frequency cepstral coefficients (MFCCs). This approach is based on a strong correlation between the spectral components of low- and high-band spectrums. Furthermore, the performances of …

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A Particle Swarm Optimization-Based Approach To Achieve Optimal Design And Operation Strategy Of Standalone Hybrid Energy Systems, Mahram Ghazvini, Ali Abbaspour Tehrani Fard, Mahmud Fotuhi Firuzabad Jan 2015

A Particle Swarm Optimization-Based Approach To Achieve Optimal Design And Operation Strategy Of Standalone Hybrid Energy Systems, Mahram Ghazvini, Ali Abbaspour Tehrani Fard, Mahmud Fotuhi Firuzabad

Turkish Journal of Electrical Engineering and Computer Sciences

As a cost-effective and reliable alternative to supply remote areas, standalone hybrid energy systems (HESs) are recently under investigation to address various concerns associated with technical, financial, and environmental issues. This paper presents a comprehensive algorithm that can simultaneously optimize the component size, operation strategy, and slope of the photovoltaic panels of a standalone HES using an improved variant of particle swarm optimization (PSO), designated as the passive congregation PSO. A new operation strategy is proposed based on the set points of the control system. The optimization algorithm determines the optimal values of the set points to efficiently optimize the …

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Tracking Control Of Elastic Joint Parallel Robots Via State-Dependent Riccati Equation, Si̇nan Kiliçaslan Jan 2015

Tracking Control Of Elastic Joint Parallel Robots Via State-Dependent Riccati Equation, Si̇nan Kiliçaslan

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a methodology for the tracking control of parallel robots having elastic joints based on the state-dependent Riccati equation is developed. Structural stiffness and damping characteristics of the joints are modeled as torsional springs and dampers, respectively. First an open-tree system is obtained by cutting some joints of the parallel robot open and its dynamic equations are written. Closed loops are then represented as constraint equations. The first and second derivatives of dependent (unactuated) joint variables are expressed in terms of independent (actuated) joint variables by making use of the constraint equations. Taking the independent joint variables, the …

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Demand Response In The Day-Ahead Operation Of An Isolated Microgrid In The Presence Of Uncertainty Of Wind Power, Javad Olamaei, Saleh Ashouri Jan 2015

Demand Response In The Day-Ahead Operation Of An Isolated Microgrid In The Presence Of Uncertainty Of Wind Power, Javad Olamaei, Saleh Ashouri

Turkish Journal of Electrical Engineering and Computer Sciences

This paper explores the utilization of demand response in the day-ahead operation of an isolated microgrid in the presence of wind units. The operation of the network with high penetration wind units (i.e. uncertainty of wind units) is modeled as a unit commitment problem. In addition, electrical power storage is modeled in a daily power curve to decrease the effect of uncertainty in the wind units. Due to avoiding large-scale complexities and the deeper study effect of demand-side management on operations, the considered network is regarded as an isolated microgrid. The demand-side management is studied as demand shifting. The simulation …

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Quality Of Service Assessment: A Case Study On Performance Benchmarking Of Cellular Network Operators In Turkey, Rana Kadioğlu, Yaser Dalveren, Ali̇ Kara Jan 2015

Quality Of Service Assessment: A Case Study On Performance Benchmarking Of Cellular Network Operators In Turkey, Rana Kadioğlu, Yaser Dalveren, Ali̇ Kara

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents findings on performance benchmarking of cellular network operators in Turkey. Benchmarking is based on measurements of standard key performance indicators (KPIs) in one of the metropolitan cities of Turkey, Ankara. Performance benchmarking is formulated by incorporating customer perception by conducting surveys on how important KPIs are from the user's point of view. KPIs are measured, with standard test equipment, by drive test method on specified routes. According to the performance benchmarking results, the GSM and UMTS network operators achieving the best performance were determined in Ankara. Speech qualities of network operators, as the most popular service, were …

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Model-Based Test Case Prioritization Using Cluster Analysis: A Soft-Computing Approach, Ni̇da Gökçe, Fevzi̇ Belli̇, Mübari̇z Emi̇nli̇, Beki̇r Taner Di̇nçer Jan 2015

Model-Based Test Case Prioritization Using Cluster Analysis: A Soft-Computing Approach, Ni̇da Gökçe, Fevzi̇ Belli̇, Mübari̇z Emi̇nli̇, Beki̇r Taner Di̇nçer

Turkish Journal of Electrical Engineering and Computer Sciences

Model-based testing is related to the particular relevant features of the software under test (SUT) and its environment. Real-life systems often require a large number of tests, which cannot exhaustively be run due to time and cost constraints. Thus, it is necessary to prioritize the test cases in accordance with their importance as the tester perceives it, usually given by several attributes of relevant events entailed. Based on event-oriented graph models, this paper proposes an approach to ranking test cases in accordance with their preference degrees. For forming preference groups, events are clustered using an unsupervised neural network and fuzzy …

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Predictive Control Of A Constrained Pressure And Level System, Erkan Kaplanoğlu, Taner Arsan, Hüseyi̇n Selçuk Varol Jan 2015

Predictive Control Of A Constrained Pressure And Level System, Erkan Kaplanoğlu, Taner Arsan, Hüseyi̇n Selçuk Varol

Turkish Journal of Electrical Engineering and Computer Sciences

The focus of this paper is the implementation of a constrained predictive control algorithm implemented in Multi-Parametric Toolbox (MPT), which is a free MATLAB toolbox for design, analysis, and implementation of controllers for constrained linear, nonlinear, and hybrid systems. In general, MPT is used for modeling systems offline. The novelty of this study is that real-time mode MPT is used in process control. We also combined the Model Predictive Control Toolbox with MPT. This novel controller is considered a real-time controller of level-pressure systems. In this study, a special type of model predictive control algorithm, the constrained continuous-time generalized control, …

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A New Hysteresis Band Current Control Technique For A Shunt Active Filter, Murat Kale, Engi̇n Özdemi̇r Jan 2015

A New Hysteresis Band Current Control Technique For A Shunt Active Filter, Murat Kale, Engi̇n Özdemi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a hysteresis band (HB) current control technique to reduce the power losses in a shunt active filter. During a switching period in the zero-crossing region, the inverter output current flows through a transistor. By changing the direction, it flows through the free-wheeling diode of the same switch in an inverter leg, or vice versa. The shunt active filter current typically has 6 zero-crossing regions during a fundamental frequency cycle. This paper presents a HB current control technique where there is not any switching in these 6 zero-crossing regions per period, which results in reducing the power losses. …

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Approximations Of Higher-Order Fractional Differentiators And Integrators Using Indirect Discretization, Richa Yadav, Maneesha Gupta Jan 2015

Approximations Of Higher-Order Fractional Differentiators And Integrators Using Indirect Discretization, Richa Yadav, Maneesha Gupta

Turkish Journal of Electrical Engineering and Computer Sciences

This paper describes new approximations of fractional order integrators (FOIs) and fractional order differentiators (FODs) by using a continued fraction expansion-based indirect discretization scheme. Different tenth-order fractional blocks have been derived by applying three different s-to-z transforms described earlier by Al-Alaoui, namely new two-segment, four-segment, and new optimized four-segment operators. A new addition has been done in the new optimized four-segment operator by modifying it by the zero reflection method. All proposed half (s$^{\pm 1/2})$ and one-fourth (s$^{\pm 1/4})$ differentiator and integrator models fulfill the stability criterion. The tenth-order fractional differ-integrators (s$^{\pm \alpha })$ based on the modified new optimized …

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Using The Finite Element Method To Calculate Parameters For A Detailed Model Of Transformer Winding For Partial Discharge Research, Seyed Mohammad Hassan Hosseini, Seyed Mohsen Enjavi Madar, Mehdi Vakilian Jan 2015

Using The Finite Element Method To Calculate Parameters For A Detailed Model Of Transformer Winding For Partial Discharge Research, Seyed Mohammad Hassan Hosseini, Seyed Mohsen Enjavi Madar, Mehdi Vakilian

Turkish Journal of Electrical Engineering and Computer Sciences

Power transformers are considered to be one of the most essential and costly pieces of equipment in a power system. Identifying insulation faults in the shortest possible time prevents the occurrence of irreparable damage. Partial discharge (PD) is one of the most significant insulation faults. The first step in the study of PD is the precise modeling of transformer winding at high frequencies. In this paper, the finite element method is used to calculate the parameters for a detailed model of transformer winding. For this reason, a detailed model of transformer winding and the analytic formulations are first presented for …

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