Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 166

Full-Text Articles in Physical Sciences and Mathematics

Simulation Of Locating Buried Objects Via Fringe Pattern-Based Measurements In An Optical Fiber Sensor-Integrated Continuous-Wave Ground-Penetrating Radar System, Asaf Behzat Şahi̇n, Hati̇ce Gonca Bulur Jan 2015

Simulation Of Locating Buried Objects Via Fringe Pattern-Based Measurements In An Optical Fiber Sensor-Integrated Continuous-Wave Ground-Penetrating Radar System, Asaf Behzat Şahi̇n, Hati̇ce Gonca Bulur

Turkish Journal of Electrical Engineering and Computer Sciences

A new ground-penetrating radar system that can determine the depth and position of a buried metal cylinder, which is the combination of an optical fiber sensor (OFS), continuous-wave transmitter, and optical communication link, is proposed and simulated in the MATLAB and Optiwave program packages. Employing an optical sensor instead of a standard radio frequency (RF) receiver offers the advantage of preventing electromagnetic interference along the sensor's main unit cable and lower amplification noise. In this paper, the electric field distribution at the OFS due to reflections from the soil surface and the buried object is obtained mathematically using Green's function. …


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 …


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. …


Estimating Facial Angles Using Radon Transform, Mohamad Amin Bakhshali, Mousa Shamsi Jan 2015

Estimating Facial Angles Using Radon Transform, Mohamad Amin Bakhshali, Mousa Shamsi

Turkish Journal of Electrical Engineering and Computer Sciences

Analysis of human facial images has become increasingly important due to its numerous applications. In this regard, extracting facial parameters is vital and various studies have been done in this field. Using these methods, different facial parameters such as the location of eyebrows, eye length, and nose angles are extracted. In this article, a robust and automatic method is introduced for determining facial angles from profile view images using the Radon transform. The Radon transform is a type of linear integration along a specific direction and angles play an important role in its performance. The proposed algorithm not only has …


Emg Classification In Obstructive Sleep Apnea Syndrome And Periodic Limb Movement Syndrome Patients By Using Wavelet Packet Transform And Extreme Learning Machine, Necmetti̇n Sezgi̇n Jan 2015

Emg Classification In Obstructive Sleep Apnea Syndrome And Periodic Limb Movement Syndrome Patients By Using Wavelet Packet Transform And Extreme Learning Machine, Necmetti̇n Sezgi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Electromyogram (EMG) signals, measured at the skin surface, provide crucial access to the muscle tones of a body. Some diseases, such as obstructive sleep apnea syndrome (OSAS) and periodic limb movement syndrome (PLMS), are closely associated with the electrical activity of muscle tones. In this paper, a hybrid model containing wavelet packet transform (WPT) plus an extreme learning machine (ELM) was proposed to classify EMG signals in OSAS and PLMS patients. At first, the WPT was used to extract the features of the EMG signal, and then these features were fed to the ELM classifier. The mean classification accuracy of …


A Mobile And Web Application-Based Recommendation System Using Color Quantization And Collaborative Filtering, Fi̇dan Kaya, Gürel Yildiz, Adnan Kavak Jan 2015

A Mobile And Web Application-Based Recommendation System Using Color Quantization And Collaborative Filtering, Fi̇dan Kaya, Gürel Yildiz, Adnan Kavak

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a recommendation system based on a mobile and web application is proposed for indoor decoration. The main contribution of this work is to apply two-stage filtering using linear matching and collaborative filtering to make recommendations. In the mobile application part, the image of the medium captured by a mobile phone is analyzed using color quantization methods, and these color analysis results along with other user-defined parameters such as height, width, and type of the product are sent to the web server. In the web application part, a large data set is first filtered via linear matching in …


Superior Decoupled Control Of Active And Reactive Power For Three-Phase Voltage Source Converters, Hesam Rahbarimagham, Erfan Maali Amiri, Behrooz Vahidi, Gevorg Babamalek Gharehpetian, Mehrdad Abedi Jan 2015

Superior Decoupled Control Of Active And Reactive Power For Three-Phase Voltage Source Converters, Hesam Rahbarimagham, Erfan Maali Amiri, Behrooz Vahidi, Gevorg Babamalek Gharehpetian, Mehrdad Abedi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an active-reactive power control strategy for voltage source converters (VSCs) based on derivation of the direct and quadrature components of the VSC output current. The proposed method utilizes a multivariable proportional-integral controller and provides almost completely decoupled control capability of the active and reactive power with almost full disturbance rejection due to step changes in the power exchanged between the VSC and the grid. It also imposes fast transient response and zero steady-state error as compared to the conventional power control approaches. The applicability of the proposed power control strategy for providing the robust stability of the …


New Metrics For Clustering Of Identical Products Over Imperfect Data, Zeki̇ Yetgi̇n, Furkan Gözükara Jan 2015

New Metrics For Clustering Of Identical Products Over Imperfect Data, Zeki̇ Yetgi̇n, Furkan Gözükara

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces the concept of product identity-clustering based on new similarity metrics and new performance metrics for web-crawled products. Product identity-clustering is defined here as the clustering of identical products, e.g., for price comparison purposes. Products blindly crawled over web sources, e.g., online marketplaces, have different description formats, where the features describing the same products differ in both number and representation formats. This problem causes imperfect feature vectors, where the vectors are considered to be not uniform in length and structure, with the features of various data types (numeric, categorical), and unknown vector structures. Furthermore, the product information usually …


Optimal Backup Parent Pools For Resilient Multicast Trees On Peer-To-Peer Networks, Emrullah Turhan Tunali, Müge Sayit Jan 2015

Optimal Backup Parent Pools For Resilient Multicast Trees On Peer-To-Peer Networks, Emrullah Turhan Tunali, Müge Sayit

Turkish Journal of Electrical Engineering and Computer Sciences

Due to churn as well as node and link failures in peer-to-peer (P2P) networks, providing resilient multicast is a challenging issue, particularly for overlay trees. In this work, we first study analytical properties of the backup parent pool that aims at improving the resilience of overlay multicast trees in P2P video streaming. We then present a novel greedy degree-constrained multicast tree construction algorithm that addresses the tradeoffs between maximizing resiliency, maximizing bandwidth utilization, and minimizing delay. The choice of essential design parameters is studied together with seamlessness of the streaming under a variety of fault scenarios. Simulation results indicate that …


Effective Cooperative Dtv Detection Using The Goertzel Algorithm, Selman Kulaç, Murat Hüsnü Sazli Jan 2015

Effective Cooperative Dtv Detection Using The Goertzel Algorithm, Selman Kulaç, Murat Hüsnü Sazli

Turkish Journal of Electrical Engineering and Computer Sciences

In digital TV (DTV) detection, to monitor the DTV spectrum, only pilot tone frequency values can be observed in order to achieve calculation and energy savings. These savings can be achieved using the Goertzel algorithm. However, more than one receiver sensor is needed in order to increase the detection quality. In this technique, the Goertzel algorithm is used for energy-efficient pilot tone detection and a new effective cooperative structure is proposed. There is no extra fusion center and more than one DTV band can be monitored with this OR rule-based cooperative structure. With this new cooperative structure, reaching the desired …


Optimal Integration Of Hybrid (Wind--Solar) System With Diesel Power Plant \Newline Using Homer, Muhammad Noman Siddique, Aftab Ahmad, Muhammad Kashif Nawaz, Syed Basit Ali Bukhari Jan 2015

Optimal Integration Of Hybrid (Wind--Solar) System With Diesel Power Plant \Newline Using Homer, Muhammad Noman Siddique, Aftab Ahmad, Muhammad Kashif Nawaz, Syed Basit Ali Bukhari

Turkish Journal of Electrical Engineering and Computer Sciences

Most energy worldwide is supplied through conventional energy sources, such as thermal, hydro, and nuclear. There have been serious energy crises in the last couple of years and so it is essential to consider renewable energy sources. This paper proposes a cost-effective solution for integrating a wind--solar system with an existing diesel power plant of a grid-connected site at Taxila, Pakistan. In the case of nonavailability of power from the grid, this diesel power plant acts as a standby system. Three cases were considered in this paper: 1) using the diesel power plant during load-shedding hours; 2) assisting the system …


Ray Tracing For Optimization Of Compound Parabolic Concentrators For Solar Collectors Of Enclosed Design, Vladimir Yurchenko, Eduard Yurchenko, Mehmet Çi̇ydem, Onat Totuk Jan 2015

Ray Tracing For Optimization Of Compound Parabolic Concentrators For Solar Collectors Of Enclosed Design, Vladimir Yurchenko, Eduard Yurchenko, Mehmet Çi̇ydem, Onat Totuk

Turkish Journal of Electrical Engineering and Computer Sciences

We present our developments in computer simulations and optimization of compound parabolic concentrators (CPCs) for solar heat collectors. Issues of both the optical and thermal optimization of CPC collectors of enclosed design are discussed. Ray tracing results for a CPC with a V-shaped absorber are presented. A range of optimal values for the apex angle of a V-shaped absorber is proposed for a CPC collector of typical design.


Integration Of Wind Power For Optimal Power System Black-Start Restoration, Amany El Zonkoly Jan 2015

Integration Of Wind Power For Optimal Power System Black-Start Restoration, Amany El Zonkoly

Turkish Journal of Electrical Engineering and Computer Sciences

Integration of wind farms into power systems may increase the risk of power system blackouts due to the uncertain nature of their output power. In the meantime, wind turbines have relatively short starting time when compared to non-black-start (NBS) generating units. For this reason, wind farms need to participate in power system restoration after blackouts. The decision of restoring a wind farm depends on its output power and the characteristics of the power system. The power system restoration should be accomplished as soon as possible. For complete power system restoration, three stages must be completed: generation restoration, transmission system restoration, …


Frequency-Adaptive Grid-Virtual-Flux Synchronization By Multiple Second-Order Generalized Integrators Under Distorted Grid Conditions, Yingjie Wang, Haiyuan Liu, Xuelong Han, Kangan Wang Jan 2015

Frequency-Adaptive Grid-Virtual-Flux Synchronization By Multiple Second-Order Generalized Integrators Under Distorted Grid Conditions, Yingjie Wang, Haiyuan Liu, Xuelong Han, Kangan Wang

Turkish Journal of Electrical Engineering and Computer Sciences

With some of the intermittent new energy and large nonlinear loads, grid voltage unbalance, harmonics, and frequency deviation are increasing year by year. The voltage source converter (VSC) is seriously affected by the various unexpected factors, and the presence of grid impedance makes the situation worse. In order to make the VSC track the nonideal grid quickly and accurately, this paper proposes a frequency-adaptive grid-virtual-flux synchronization by multiple second-order generalized integrators (MSOGI-GVFS). Key expressions of the MSOGI-GVFS and its frequency response characteristics are described in this paper. A second-order generalized integrator configured as a quadrature signal generator generates a specific-frequency …


Automatic Vehicle Classification Using Fast Neural Network And Classical Neural Network For Traffic Monitoring, Mahammad Abdul Hannan, Chew Teik Gee, Mohammad Saleh Javadi Jan 2015

Automatic Vehicle Classification Using Fast Neural Network And Classical Neural Network For Traffic Monitoring, Mahammad Abdul Hannan, Chew Teik Gee, Mohammad Saleh Javadi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces an automatic vehicle classification for traffic monitoring using image processing. In this technique the fast neural network (FNN) as a primary classifier and then the classical neural network (CNN) as a final classifier are applied to achieve high classification performance. The FNN gains a useful correlation between the input and the weighted neurons using a multilayer perceptron to provide detection with a high level of accuracy. The Fourier transform is used to speed up the procedure. In the CNN, a lighting normalization method is employed to reduce the effect of variations in illumination. The combination of the …


A Real-Time American Sign Language Word Recognition System Based On Neural Networks And A Probabilistic Model, Neelesh Sarawate, Ming Chan. Leu, Cemi̇l Öz Jan 2015

A Real-Time American Sign Language Word Recognition System Based On Neural Networks And A Probabilistic Model, Neelesh Sarawate, Ming Chan. Leu, Cemi̇l Öz

Turkish Journal of Electrical Engineering and Computer Sciences

The development of an American Sign Language (ASL) word recognition system based on neural networks and a probabilistic model is presented. We use a CyberGlove and a Flock of Birds motion tracker to extract the gesture data. The finger joint angle data obtained from the sensory glove defines the handshape while the data from the motion tracker describes the trajectory of the hand movement. The four gesture features, namely handshape, hand position, hand orientation, and hand movement, are recognized using different functions that include backpropagation neural networks. The sequence of these features is used to generate a specific sign or …


Impedance Modeling For Classification Of Flavored Green Teas, Munendra Singh, Sunil Semwal, Ashavani Kumar, Shailendra Singh Jan 2015

Impedance Modeling For Classification Of Flavored Green Teas, Munendra Singh, Sunil Semwal, Ashavani Kumar, Shailendra Singh

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes an electrical impedance model of flavored green teas. Typically, impedance data of flavored green teas, obtained by electrochemical impedance spectroscopy (EIS), fit into an equivalent circuit that represents the physical and chemical processes taking place in it. The total impedance of each flavor alone is not sufficient, but different values of impedance parameters in the electrical impedance model are responsible for better classification of flavored green teas. Successfully classified data on the basis of their flavors were obtained by different support vector machine (SVM) techniques with encouraging results. The results show that a linear SVM has better …


2d High-Frequency Forward-Looking Sonar Simulator Based On Continuous Surfaces Approach, Hakan Saç, Mehmet Kemal Leblebi̇ci̇oğlu, Gözde Akar Jan 2015

2d High-Frequency Forward-Looking Sonar Simulator Based On Continuous Surfaces Approach, Hakan Saç, Mehmet Kemal Leblebi̇ci̇oğlu, Gözde Akar

Turkish Journal of Electrical Engineering and Computer Sciences

Optical cameras give detailed images in clear waters. However, in dark or turbid waters, information coming from electro-optical sensors is insufficient for accurate scene perception. Imaging sonars, also known as acoustic cameras, can provide enhanced target details in these scenarios. In this paper, a computationally efficient 2D high-frequency, forward-looking sonar image simulator is presented. Stages and requirements of the image formation process are explained in detail. For the postprocessing of the returned sonar signals, a novel computation engine is proposed based on the geometric structures of the simulated surfaces. By treating all the continuous surfaces separately, the simulator is able …


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, …


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 …


Adaptive Network-Based Inference System Models On Multiband Patch Antenna Design, Erdem Demi̇rci̇oğlu, Murat Hüsnü Sazli, Orhan Şengül, Şehabeddi̇n Taha İmeci̇, Hakki Alparslan Ilgin Jan 2015

Adaptive Network-Based Inference System Models On Multiband Patch Antenna Design, Erdem Demi̇rci̇oğlu, Murat Hüsnü Sazli, Orhan Şengül, Şehabeddi̇n Taha İmeci̇, Hakki Alparslan Ilgin

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an adaptive network-based fuzzy inference system (ANFIS) for multiband microstrip patch antenna (MMPA) modeling is proposed. The MMPA includes a single patch with inverted L-shaped stubs on the edges. The antenna production process needs iterative runs of the electromagnetic (EM) simulator, fabricating and testing the simulated antenna to find the optimum geometry. Production processes (design, simulation, fabrication, and testing) and the cost computation time add to the overall manufacturing expenses. A computer-aided modeling approach using the ANFIS is developed and trained with data acquired from the EM simulators, Sonnet Suites and AWR AXIEM, and measurement data. The …


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 …


Regulation Of Methane Gas Output From An Anaerobic Reactor System Using Moving Horizon $H_{\Infty }$ Control, Fatma Yildiz Taşcikaraoğlu, Şeref Naci̇ Engi̇n Jan 2015

Regulation Of Methane Gas Output From An Anaerobic Reactor System Using Moving Horizon $H_{\Infty }$ Control, Fatma Yildiz Taşcikaraoğlu, Şeref Naci̇ Engi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the moving horizon $\mathcal{H}_{\infty }$\textbf{ }control used for tracking a desired methane gas output from an anaerobic wastewater treatment reactor is compared with classical $\mathcal{H}_{\infty }$ control and a proportional-integral-derivative controller. The nonlinear system is first linearized around the set of equilibrium and operating points selected, and then the linear matrix inequalities required to comply with the constraints and guarantee the stability are constructed. Finally, the experimental results are obtained by implementing the control method in a MATLAB environment. It is concluded that moving horizon $\mathcal{H}_{\infty }$ control yields satisfactory results.


Capacitive Sensor Supporting Multiple Touch Switches Using A Resistor String, Kwangsu Seong Jan 2015

Capacitive Sensor Supporting Multiple Touch Switches Using A Resistor String, Kwangsu Seong

Turkish Journal of Electrical Engineering and Computer Sciences

In a low-cost integrated circuit (IC) chip, the packaging cost is a considerable portion of the total manufacturing cost of the chip. As the packaging cost is directly related to the total number of I/O pins, it is highly desirable to minimize the number of I/O pins while maintaining the same functionality. We propose a capacitive sensor that supports multiple touch switches with only two IC pins. The electrode plates of the touch switches are placed at the ends of a resistor string and between every two adjacent resistors in the resistor string. The proposed method measures rise times at …


A New High-Performance Current-Mode Fuzzy Membership Function Circuit And Its Application, Turgay Temel Jan 2015

A New High-Performance Current-Mode Fuzzy Membership Function Circuit And Its Application, Turgay Temel

Turkish Journal of Electrical Engineering and Computer Sciences

A new current-mode fuzzy-membership function circuit is proposed. The circuit has a very compact and simple architecture based on the simultaneous use of winner- and loser-take-all topologies. The circuit has also the advantage of easily adjusting generated membership function characteristics such as center or mean and width with a straightforward application of respective input currents. It is shown that the new circuit outperforms previous counterparts in terms of speed, power consumption, layout area, and robustness to variations in design parameters and errors. As an application, a fuzzy-classifier is designed with a new membership circuit as a seven fuzzy level controller.


Performance Improvement Of Three-Phase Self-Excited Induction Generator Feeding Induction Motor Load, Jyotirmayee Dalei, Kanungo Barada Mohanty Jan 2015

Performance Improvement Of Three-Phase Self-Excited Induction Generator Feeding Induction Motor Load, Jyotirmayee Dalei, Kanungo Barada Mohanty

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the transient and steady-state performances of an isolated self-excited induction generator driven by a wind turbine and feeding power to a dynamic load such as a three-phase induction motor are analyzed. Mathematical modeling and simulation study of the whole system, including the wind turbine, induction generator, capacitor, pulse width modulated voltage source inverter, and dynamic load, are carried out with closed-loop voltage and frequency controller. The complete system is modeled in the stationary $d-q$ frame and validated by comparing simulation and experimental results at no-load. The same mathematical model is then used to study the transient performance …


Capacity Allocation Of Hybrid Solar-Wind Energy System Based On Discrete Probabilistic Method, Chengjin Ye, Minxiang Huang Jan 2015

Capacity Allocation Of Hybrid Solar-Wind Energy System Based On Discrete Probabilistic Method, Chengjin Ye, Minxiang Huang

Turkish Journal of Electrical Engineering and Computer Sciences

Complementary renewable energies like wind and solar power may be more sufficient to satisfy reliability requirements. This paper proposes a quantitative capacity allocation method of a hybrid wind and solar energy system. First, discrete probability distributions are established to model the random factors including the volatility of power outputs and the failure of components. Then a multiobjective optimization model is formulated with objectives of minimization of the total investment, the nodal voltages violating limits probability, and power supply inadequacy probability. For the purpose of fast probability computing with a satisfactory precision degree, an innovative probabilistic load flow algorithm is introduced, …


Improving The Drain-Current Expression Of Bsim4 For Hot-Carrier Degradation Modeling That Is Suitable For Analog Applications, Gürsel Düzenli̇ Jan 2015

Improving The Drain-Current Expression Of Bsim4 For Hot-Carrier Degradation Modeling That Is Suitable For Analog Applications, Gürsel Düzenli̇

Turkish Journal of Electrical Engineering and Computer Sciences

The reliability evaluation of MOS transistors is one of the most important subjects in device engineering and VLSI design. The down-scaling of device dimensions adversely affects device reliability and lifetime. Although different factors contribute to device reliability and lifetime, the most influential factor is hot-carrier degradation. Furthermore, hot-carrier degradation affects each application uniquely. In analog applications, hot-carrier degradation is more complex and diverse relative to digital applications. In this study, we improve the BSIM4 drain-current model to develop a hot-carrier degradation model that is suitable for both analog and digital applications. Our approach is readily applicable to all process technologies …


Multilevel Hybrid Cascade-Stack Inverter With Substantial Reduction In Switches Number And Power Losses, Mahdi Toopchi Khosroshahi, Ali Ajami, Ata Ollah Mokhberdoran, Mohammadreza Jannati Oskuee Jan 2015

Multilevel Hybrid Cascade-Stack Inverter With Substantial Reduction In Switches Number And Power Losses, Mahdi Toopchi Khosroshahi, Ali Ajami, Ata Ollah Mokhberdoran, Mohammadreza Jannati Oskuee

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a multilevel hybrid cascade-stack (HCS) converter. Recently, different new topologies for cascade-type converters have been suggested with the goal of reducing switch number, loss, switch PIV, etc. Meanwhile, output voltage steps increase, and the number of switches is predominately reduced in the suggested inverter in comparison to conventional cascade converters. Additionally, a reduction in the number of on-state switches in the introduced topology causes power loss and voltage drop to decrease. Firstly, the fundamental parts of inverter configuration are described. Afterwards, symmetric and asymmetric converter types are discussed. Simulation and experimental results for 11- and 23-level symmetric …


An Ofdm Throughput Analysis For Cognitive Radio Application In Contiguous Or Noncontiguous Tv White Spaces, Cebrai̇l Çi̇fli̇kli̇, Ahmet Turgut Tuncer, Yusuf Öztürk Jan 2015

An Ofdm Throughput Analysis For Cognitive Radio Application In Contiguous Or Noncontiguous Tv White Spaces, Cebrai̇l Çi̇fli̇kli̇, Ahmet Turgut Tuncer, Yusuf Öztürk

Turkish Journal of Electrical Engineering and Computer Sciences

Radio frequency spectrum is a finite and scarce resource. Efficient use of the radio frequency spectrum is a fundamental research issue. Since a large portion of the assigned radio frequency spectrum is used only sporadically, the bands currently allocated to TV services can be opportunistically reassigned to support broadband networking services while continuing to provide broadcast TV. The fragmented and unused TV channels named white spaces have a considerable amount of bandwidth potential and long transmission ranges. Bandwidth scalability can be supported by bonding multiple contiguous or noncontiguous consecutive channels using orthogonal frequency division multiplexing (OFDM)-based cognitive radio. In this …