Design And Ground Plane Optimization Of A Cpw-Fed Ultra-Wideband Antenna,
2011
TÜBİTAK
Design And Ground Plane Optimization Of A Cpw-Fed Ultra-Wideband Antenna, Mohammed Al-Husseini, Ali Ramadan, Youssef Tawk, Ali El-Hajj, Karim Y. Kabalan
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, an ultra-wideband antenna based on an egg-shaped conductor and a co-planar waveguide (CPW) feed is presented. The ground plane incorporates an egg-shaped slot with parametrized center and dimensions. By resizing the slot and moving its center, a slotted or a partial ground can be obtained. Based on this configuration, a parametric study that aims at achieving the best ultra-wideband (UWB) response of the antenna is done. The study shows that an excellent UWB response is achieved for a certain ground slot size, beyond which the response starts to degrade. However, as the slot size tends to infinity, …
Cognitive And Encrypted Communications: State Of The Art And A New Approach For Frequency-Agile Filters,
2011
TÜBİTAK
Cognitive And Encrypted Communications: State Of The Art And A New Approach For Frequency-Agile Filters, Yahya Lakys, Balwant Godara, Alain Fabre
Turkish Journal of Electrical Engineering and Computer Sciences
Several communication techniques are investigated in the first part of this paper: software radio, cognitive radio and encrypted communications. State of the art of research on agile and reconfigurable filters, passive as well as active, necessary for transceivers is then made and various tables for comparison are given. In the third part, a new theory for a 2^{nd}-order frequency-agile filter is introduced. The center frequency of the filter is proportional to the gain of a feedback amplifier and thus can be tuned over a wide frequency range. This new theory is thereafter generalized to the n^{th}-class leading to a center …
Four Quadrant Fgmos Analog Multiplier,
2011
TÜBİTAK
Four Quadrant Fgmos Analog Multiplier, Si̇nem Keleş, Hulusi̇ Hakan Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
A novel four-quadrant analog multiplier using floating gate MOS (FGMOS) transistors operating in the saturation region is presented. The drain current is proportional to the square of the weighted sum of the input signals. This square law characteristic of the FGMOS transistor is used to implement the quarter square identity by utilizing only six FGMOS transistors. The main features of this remarkably simple multiplier circuit configuration are the large input signal range equal to 100% of the supply voltage, nonlinearity of 0.0081%, bandwidth of 1.4--1.5 Ghz and THD of maximum 2.67% (while the inputs are at their maximum values).
An Extended Component-Based Reliability Model For Protective Systems To Determine Routine Test Schedule,
2011
TÜBİTAK
An Extended Component-Based Reliability Model For Protective Systems To Determine Routine Test Schedule, Amir Abbarin, Mahmoud Fotuhi Firuzabad, Aydoğan Özdemi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a novel approach for evaluating the reliability of protective systems taking into account its components reliability. In this paper, a previously proposed extended model is used for a directional over-current scheme. In the extended model, the impacts of individual protective components are taken into account. An optimum routine test schedule is determined for each protective component as a separate unit. A comparison is made to show that the proposed approach has excellence over conventional routine test inspections. Impacts of factors such as circuit breaker inadvertent opening, required time for performing routine test inspections, human mistakes and self-checking …
Remote Mutual Authentication And Key Agreement Scheme Based On Elliptic Curve Cryptosystem,
2011
TÜBİTAK
Remote Mutual Authentication And Key Agreement Scheme Based On Elliptic Curve Cryptosystem, Eunjun Yoon
Turkish Journal of Electrical Engineering and Computer Sciences
Remote mutual authentication is an important part of security, along with confidentiality and integrity, for systems that allow remote access over untrustworthy networks, like the Internet. In 2006, Shieh-Wang pointed out the weakness of Juang's remote mutual authentication scheme using smart card and further proposed a novel remote user authentication scheme using smart card. However, this paper demonstrates that Shieh-Wang's scheme still does not provide perfect forward secrecy and is vulnerable to a privileged insider's attack. We also present an improved scheme based on the Elliptic Curve Diffie-Hellman problem (ECDHP) and secure one-way hash function, in order to isolate such …
Fully Integrated Universal Biquads Using Operational Transresistance Amplifiers With Mos-C Realization,
2011
TÜBİTAK
Fully Integrated Universal Biquads Using Operational Transresistance Amplifiers With Mos-C Realization, Ahmet Gökçen, Selçuk Kilinç, Uğur Çam
Turkish Journal of Electrical Engineering and Computer Sciences
Universal biquadratic filters employing operational transresistance amplifiers are presented. All 5 different second-order filtering functions, namely low-pass, high-pass, band-pass, notch, and all-pass, can be realized. The quality factor of the filters can be adjusted electronically without affecting resonant frequency. The configuration can be made fully integrated based on MOS-C realization, by making use of the current differencing and internally grounded inputs of OTRA. PSpice simulation results are given to verify the theoretical analysis.
Obtaining The Secondary Impedance Of Single-Sided Linear Induction Motor With A Double Layer Reaction Rail: A New Approach,
2011
TÜBİTAK
Obtaining The Secondary Impedance Of Single-Sided Linear Induction Motor With A Double Layer Reaction Rail: A New Approach, Ali̇ Suat Gerçek, Vedat Mehmet Karsli
Turkish Journal of Electrical Engineering and Computer Sciences
In the performance calculations of single-sided linear induction motor (SLIM),the equivalent circuit technique (ECT) is used. In this paper, a new approach is proposed for obtaining the secondary impedance of single-sided linear induction motor (SLIM) with a double layer reaction rail by using the layered secondary model. The proposed method improves the ECT technique by considering the saturation effect and the non-linear complex equivalent relative permeability. This study also examines the contributions of other electromagnetic effects, such as longitudinal end effect and transverse edge effect as well. Our method is applied to the SLIM and computed results of the method …
A Study On Influence Of Borax To Polyester Insulators,
2011
TÜBİTAK
A Study On Influence Of Borax To Polyester Insulators, Aysel Ersoy, Ayten Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
In this study the effect of borax on polyester insulators is investigated by evaluating the tracking and erosion resistance using the inclined plane test. The test procedure follows the ASTM D2303 standard. During the test, 50 Hz current was acquired from the ground electrode allowing a sampling rate of 48000 samples per second. The effect of borax concentration on the glass transition and the degradation temperature is studied by employing differential scanning calorimetry (DSC) analysis. The addition of borax to the unsaturated polyester resulted in an increase in the glass transition temperature, while the addition of 0.5% of borax by …
Low-Complexity Parameters Estimator For Multiple 2d Domain Incoherently Distributed Sources,
2011
TÜBİTAK
Low-Complexity Parameters Estimator For Multiple 2d Domain Incoherently Distributed Sources, Xiansheng Guo, Qun Wan, Xiaofeng Shen, Heng Dou
Turkish Journal of Electrical Engineering and Computer Sciences
A new low-complexity parameters estimator for multiple two-dimensional (2D) domain incoherently distributed (ID) sources is presented. One 2D domain ID source is parameterized with four parameters, the central azimuth direction-of-arrival (DOA), azimuth angular spread, central elevation DOA and elevation angular spread. Based on the eigenstructure between the steering matrix and signal subspace, an average total least-squares via rotational invariance technique (TLS-ESPRIT) is used to estimate the central elevation DOA, and then a generalized multiple signal classification (GMUSIC) algorithm is derived to estimate the central azimuth DOA. Utilizing preliminary estimates obtained at a pre-processing stage, the angular spread parameters can be …
Rate 1 Space-Time And Space-Frequency Spreading Diversity Technique,
2011
TÜBİTAK
Rate 1 Space-Time And Space-Frequency Spreading Diversity Technique, Gökçe Hacioğlu, Ali̇ Gangal
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a rate 1 transmitter diversity technique is proposed. The proposed technique uses spreading transform and space-time block coding (STBC) together. Space-time, space-frequency, and frequency diversity applications of the proposed technique are shown. The code matrix of the proposed technique can be designed systematically. The proposed technique needs the channel coefficients to stay constant over transmission of 2 rows of the coding matrix regardless of the size of the coding matrix or the diversity order. However, joint detection of the symbols is required for the proposed technique. We used computer simulations to compare our technique with the quasi-orthogonal …
Ecg Denoising On Bivariate Shrinkage Function Exploiting Interscale Dependency Of Wavelet Coefficients,
2011
TÜBİTAK
Ecg Denoising On Bivariate Shrinkage Function Exploiting Interscale Dependency Of Wavelet Coefficients, Sema Kayhan, Ergun Erçelebi̇
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new method for electrocardiogram (ECG) denoising based on bivariate shrinkage functions exploiting the interscale dependency of wavelet coefficients. Most nonlinear thresholding methods based on wavelet transform denoising assume that the wavelet coefficients are independent. However, wavelet coefficients of ECG signals have significant dependencies. In this paper, we proposed a new method by considering the dependencies between the coefficients and their parents in detail on a bivariate shrinkage function for denoising of an ECG signal corrupted by different types of noises, such as muscle artifact noise, electrode motion, and white noise. In real-time applications, reduction of computational …
Decentralized Robust Load-Frequency Control Of Power System Based On Quantitative Feedback Theory,
2011
TÜBİTAK
Decentralized Robust Load-Frequency Control Of Power System Based On Quantitative Feedback Theory, Aidin Sakhavati, Gevork Gharehpetian, Seyed Hossein Hosseini
Turkish Journal of Electrical Engineering and Computer Sciences
This paper aims at investigating the problem of Load Frequency Control (LFC) in interconnected power systems in order to obtain robustness against uncertainties. A design method for a robust controller, based on Quantitative Feedback Theory (QFT), has been presented in this paper. For a two-area power system, the simulation results show that the system response with the proposed QFT controller exhibits transient response beyond PI controllers. It is also shown that the transient response of the tie line power can also be improved.
Sliding Mode Controller Gain Adaptation And Chattering Reduction Techniques For Dsp-Based Pm Dc Motor Drives,
2011
TÜBİTAK
Sliding Mode Controller Gain Adaptation And Chattering Reduction Techniques For Dsp-Based Pm Dc Motor Drives, Mehmet Dal, Remus Teodorescu
Turkish Journal of Electrical Engineering and Computer Sciences
In order to achieve and maintain the prospective benefits of sliding mode control (SMC) methodology, the phenomenon known as ``chattering'', the main obstacle encountered in real-time applications, has to be suppressed. In this study, two promising switching control gain adaptation and chattering reduction techniques are investigated, and the effectiveness of chattering suppression for current regulation of PM DC drives is tested. The sampling rate was also examined to determine how it affects the amplitude of chattering. This paper concentrates on various combinations of observer-based methods in order to find the best solution for chattering reduction. To find a practical solution …
Minimization Of Load Shedding By Sequential Use Of Linear Programming And Particle Swarm Optimization,
2011
TÜBİTAK
Minimization Of Load Shedding By Sequential Use Of Linear Programming And Particle Swarm Optimization, Mehrdad Tarafdar Hagh, Sadjad Galvani
Turkish Journal of Electrical Engineering and Computer Sciences
Minimization of load shedding during contingency conditions is solved as an optimization problem. As a new topic, instead of local load shedding, total load shedding of a large power system is considered. Power generation rescheduling is considered to minimize the load shedding, as well. Different importance factors for buses are also considered. The linear programming method (LP) is used to solve this problem in a short period of time without considering some power system constraints. Particle swarm optimization (PSO) is also used to solve the problem by considering all power system constraints, but with a longer solving time. Finally, a …
Design Of Cdba-Based Active Polyphase Filter For Low-If Receiver Applications,
2011
TÜBİTAK
Design Of Cdba-Based Active Polyphase Filter For Low-If Receiver Applications, Mehmet Sağbaş
Turkish Journal of Electrical Engineering and Computer Sciences
A novel first-order active-RC polyphase filter section, using current differencing buffered amplifiers (CDBAs), is presented. The section uses 6 resistors, 2 capacitors, and 2 CDBAs. The transfer function of the proposed section has a single pole and optionally a single zero. Increasing the number of cascading sections, any higher order polyphase filter can be realized. This paper also introduces the leakage caused by element deviation and the effects of the amplifier in nonideal cases. Furthermore, nonideal performances of the proposed filter section are tested with PSpice simulations.
Measuring Traffic Flow And Classifying Vehicle Types: A Surveillance Video Based Approach,
2011
TÜBİTAK
Measuring Traffic Flow And Classifying Vehicle Types: A Surveillance Video Based Approach, Erhan İnce
Turkish Journal of Electrical Engineering and Computer Sciences
The paper presents a vehicle counting method based on invariant moments and shadow aware foreground masks. Estimation of the background and the segmentation of foreground regions can be done using either the Mixture of Gaussians model (MoG) or an improved version of the Group Based Histogram (GBH) technique. The work demonstrates that, even though the improved GBH method delivers performance just as good as MoG, considering computational efficiency, MoG is more suitable. Shadow aware binary masks for each frame are formed by using background subtraction and shadow removal in the Hue Saturation and Value (HSV) domain. To determine new vehicles …
Performance Evaluation Of Nonparametric Ica Algorithm For Fetal Ecg Extraction,
2011
TÜBİTAK
Performance Evaluation Of Nonparametric Ica Algorithm For Fetal Ecg Extraction, Yusuf Sevi̇m, Ayten Atasoy
Turkish Journal of Electrical Engineering and Computer Sciences
Fetal electrocardiograms (FECG) contain important indications about the health and condition of the fetus. In this respect, it is crucial to apply a robust algorithm to ECG data for extraction of the FECG signal. Most of the independent component analysis (ICA) algorithms used for this purpose rely on simple statistical models. Such algorithms can fail to separate desired signals when the assumed statistical model is inaccurate. Statistical models can be estimated accurately using kernel density estimation methods. Therefore, the kernel density estimation method was used in this paper for building an ICA algorithm (nonparametric ICA: NpICA) and the algorithm was …
Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac,
2011
TÜBİTAK
Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman
Turkish Journal of Electrical Engineering and Computer Sciences
Recognition of cardiac arrhythmias by electrocardiogram (ECG) is an important issue for diagnosis of cardiac abnormalities. Many studies on recognition of cardiac arrhythmias by ECG, using various techniques, have been performed in the past 20 years. Artificial neural networks (ANNs) are the most widely used tool in medical diagnosis systems (MDS) because of their powerful prediction characteristics. An ANN model is inspired by real biological neural networks, with a parallel structure that is potentially fast for computation. However, the suggested ANN architectures in the literature can only be run sequentially, on powerful processors, due to their complexity. Our approach enables …
Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances,
2011
TÜBİTAK
Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a learning controller for robot manipulators is developed. The controller is proven to yield in a semi-global asymptotic result in the presence of additive input and output disturbances. Lyapunov-based techniques are used to guarantee that the tracking error is asymptotically driven to zero. Numerical simulation results are presented to demonstrate the viability of the proposed learning controller.
A Multi-Lateral Rehabilitation System,
2011
TÜBİTAK
A Multi-Lateral Rehabilitation System, Aykut Ci̇han Satici, Ahmetcan Erdoğan, Volkan Patoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a multi-lateral shared control concept for robot assisted rehabilitation. In particular, a dual-user force-feedback teleoperation control architecture is implemented on a forearm-wrist rehabilitation system consisting of two kinematically dissimilar robotic devices. The multi-lateral rehabilitation system allows for patients to train with on-line virtual dynamic tasks in collaboration with a therapist. Different control authority can be assigned to each agent so that therapists can guide or evaluate movements of patients, or share the control with them. The collaboration is implemented using a dual-user force-feedback teleoperation control architecture, in which a dominance factor determines the authority of each agent …
