Istanbul University - Journal of Electrical & Electronics Engineering (IU - JEEE) Issue 6/1 - Articles   1 Subject Study On The Driving Model Of Ultrasonic Motor Download Download this article. Language English Author Li HUAFENG, Zhao CHUNSHENG, Gu CHENGLIN Keywords Ultrasonic motor; Driving model Abstract The interface contact model between the stator and the rotor of traveling wave ultrasonic motor is presented, assuming that the rigid stator contacts the flexible rotor over an area, and the frictional material is regarded as distributed linear spring and without shearing deformation, from which the mechanical characteristic of the motor and the interface transmission efficiency are derived. And then the effects of the motor's parameters on its performance are investigated, which will be helpful to the design of the ultrasonic motor.   2 Subject Some Considerations Of Designing A High Performance Rogowski Coil For Pulsed Current Measurement Download Download this article. Language English Author Li WEIBO, Mao CHENGXIONG, Lu JIMING Keywords Performance of Rogowski coil, dimension-and electromagnetic- parameters, pulsed current measurement. Abstract Rogowski coil is made having nonmagnetic material in a core, which results in that Rogowski coil has typically been used to measure large pulsed currents. Therefore, studying the high-frequency performance of the coil is important to design an appropriate sensor for measuring heavy currents. The paper presents some analysis on the influences of the dimension and electromagnetic parameters of the coil. Some considerations and methods of optimizing these parameters have been proposed. Issues related to the geometrical effects and error characters of Rogowski coil are discussed. The prototype equipment embodies a differentiating Rogowski coil, specifically designed to obtain the reliability and scalability to meet the needs of measurement applications. Experimental results verify the validity of the proposed considerations for measuring pulsed currents.   3 Subject Texture Analysis Based Iris Recognition Download Download this article. Language English Author Güray GÜRKAN, Aydın AKAN Keywords Biometrics, Iris Recognition, Gabor Filters, Average Absolute Deviation, Log-Sampling. Abstract In this paper, we present a new method for personal identification, based on iris patterns. The method composed of iris image acquisition, image preprocessing, feature extraction and finally decision stages. Normalized iris images are vertically log-sampled and filtered by circular symmetric Gabor filters. The output of filters are windowed and mean absolute deviation of pixels in the window are calculated as the feature vectors. The proposed method has the desired properties of an iris recognition system such as scale and rotation invariance. The system is realized in Windows platform using Delphi compiler.   4 Subject Fast Calculation Of All Stabilizing Gains For Discrete-Time Systems Download Download this article. Language English Author Nevra BAYHAN, Mehmet Turan SÖYLEMEZ Keywords Bilinear Transformation, Nyquist's Criterion, Chebyshev Polynomials Abstract In this paper, two methods for calculating all stabilizing gains for discrete-time systems are given. The first method focuses on converting the problem using a bilinear transformation and then applying a previously developed theorem for continuous time systems. Unlike previous results, the method introduced here does not use the Generalised Hermite-Biehler Theorem and therefore provides a computational advantage. The second method demonstrates the use of Chebyshev Polynomials in the solution of the problem.   5 Subject Determination Of The Next Stopping Floor In Elevator Traffic Control By Means Of Neural Networks Download Download this article. Language English Author C.Erdem İMRAK, Mustafa ÖZKIRIM Keywords backpropagation, elevator control, group control, next stopping floor, neural networks. Abstract When a group of lifts serve together it is important coordinate the movements of the individual lifts in such a way that the lift group should operate efficiently. This is dealt with elevator control systems, which have become more and more complicated due to their nature of intelligence. Neural networks, which have been proved to be successful in many fields, can also be applied to the next stopping floor problem in elevator traffic control algorithms. In particular, neural networks can offer better solutions to the next stopping floor problem when compared to the classical traffic control methods. Elevator control algorithms based on neural networks can dynamically learn the behavior of an elevator system and predict the next floors to stop by considering what has been learnt by processing the changes in passenger service demand pattern. Neural networks have been used to build a one step ahead predictor for elevator traffic pattern. In this paper a neural network algorithm is apllied to obtain a better solution to the next stopping floor problem in elevator group control and its learning capability is assessed by means of simulation software developed.   6 Subject An Application Of Kirchhoff Depth Imaging Technique To The Multi-Channel Shallow Seismic Reflection Data Download Download this article. Language English Author Zakir KANBUR Keywords Seismic reflection, Pre-stack Kirchhoff Depth Migration, Shallow seismic reflection data Abstract Applying Pre-satck Kirchhoff Depth Migration Technique to the multi-channel shallow seismic reflection data may be obtained successful results as well as obtained from the deep seismic reflection data. In order to test this approch, the technique converted the data, contains 40 seismic reflection records with 0.2 second record length and collected along straight profile, into the 120 meter depth section. The geometry of the layers and folding and faulting was revealed as depth as 120 meter in the image of the section. By comparing the fault plane emerged on the image with the corrupted parabola in seismic reflection records at the corresponding point, it is concluded that Pre-stack Kirchhoff Depth Migration Technique is capable not only imaging the layers at their correct places but also handling the parabola irregularity due to the fault structures and therefore it can be applied successfully to any shallow seismic reflection data too.   7 Subject Investigation Of The Interaction Between Chaotic Musics And Human's Brain Download Download this article. Language English Author Mehmet ENGIN, Tayfun DALBASTI, Emre ERTUGRUL, Sinan OZ, Erkan Zeki ENGIN Keywords Music cognition, chaotic analysis, EEG, medical treatment. Abstract In this paper, we examined methods for analysing EEG (Electroencephalogram) during music listening and the relationship between EEG and music cognition. We especially focused on non-linear signal analysis for EEGs. We calculated correlation dimension (CD) and Lyapunov exponents (LE) signals of interest for two healthy subjects. Thus, we try to obtain the experimental results from the beginnings works about the possibility of medical treatment by music.   8 Subject Optical Burst Switching Protocols In All-Optical Networks Download Download this article. Language English Author Pınar KIRCI, A.Halim ZAIM Keywords Optical Burst Switching, Optical Packet Switching, JIT Protocol. Abstract In this paper, all optical network's general structure is briefly described and all optical network's optical switching methods is concantrated on. All optical network's classification is presented according to switching methods and burst switching methods studied carefully.The protocols which are defined for burst switching are studied. One of these protocols JET (Just-Enough-Time) which is mostly studied, is introduced. And the other protocol JIT (Just-In-Time) is presented detailly. The main aim of this study is explaining the all optical network's working mechanism generally, and examine the processing structure of JIT protocol.   9 Subject Tissue-Motion Analysis Of Artery Pulsation In Cranial Ultrasonogram Of Newborn Baby Download Download this article. Language English Author Mohiuddin AHMAD, Mostafa Zaman CHOWDHURY, Md. Jahangir ALAM Keywords Tissue-motion, pulsation, newborn baby, optical flow Abstract Tissue-motion is an important physical parameter that can be considered in discussing the strength of artery pulsation of newborn baby for pediatrics diagnosis. In this paper, we have used optical flow technique to determine the tissue-motion velocity quantitatively in cranial ultrasonogram of newborn baby. We have estimated the tissue-motion by using gradient-based optical flow method and then the time variant tissue motion velocities are analyzed by using Fourier transform. Strong pulsation is observed in the harmonic frequency of tissue-motion that has a relation to the heartbeat frequency of a newborn baby.   10 Subject Rule Based Detection Of Lung Nodules In CT Images Download Download this article. Language English Author Serhat OZEKES, A.Yılmaz CAMURCU Keywords Computer aided diagnosis, lung nodule detection, computed tomography Abstract In this paper, we present a computer aided diagnosis (CAD) system for lung nodule detection in computed tomography (CT) images. Here, the density values of pixels in CT image slices are used and scanning the pixels in 8 directions is evaluated. By using various thresholds while scanning the pixels, lung nodule shapes and parts of the normal structure shapes (blood vessels, bronchus etc.) are found. All shapes are labeled using connected component labeling (CCL). Two rules are used to distinguish lung nodules from normal structures. In the first rule, the euclidean distance of the shape, and in the second rule the regularity which is the ratio of euclidean distance to thickness of the shape is considered. The performance of the system is evaluated using a test set which contains totally 35 normal and abnormal images, with 61 nodules. When results are compared with the second look reviews of a chest radiologist, it is seen that the system achieved 89% sensitivity with 0.457 false positives (FPs) per image. The proposed system which obtains high sensitivity with acceptable low number of false positives per image, may improve the computerized analysis of lung CTs and early diagnosis of lung nodules.   11 Subject Power System Stabilization By A Double-Fed Induction Machine With A Flywheel Energy Storage System Download Download this article. Language English Author Gang LI, Shijie CHENG, Jinyu WEN, Yuan PAN, Jia MA   Keywords AC excitation, flywheel energy storage, vector control, stator flux linkage orientation, stability control Abstract This paper proposed a new idea of using a large-mass varying-speed flywheel as an energy storage element to form a novel FACTS device called multi-functional Flexible Power Conditioner (FPC). The novel device consists of a double-fed induction machine (DFIM) and a voltage-source pulse width modulation (PWM) rectifier-inverter used as an AC exciter. By changing the speed of the rotating machine, the kinetic energy stored in the rotor with the flywheel will be changed. With an appropriate control strategy, it is able to realize an independent active and reactive power exchanging between the FPC and the grid. Similar to that of the Superconducting Magnetic Energy Storage (SMES), the FPC can be used to improve the stability of power system as well as the quality of power supply. Additional advantage of the FPC over the SMES based device is that it is easy to develop and to operate. Therefore, the cost will be greatly reduced. In order to increase performance of the proposed device, an improved stator flux linkage orientated control strategy for FPC is proposed in the paper. Simulation result of applying the proposed device in a two-machine and an infinite bus system shows that the proposed control provides excellent dynamic characteristics. Very encouraging results are obtained.   12 Subject Voltage Mode First Order Allpass Filter And Quadrature Oscillator Employing Fully Differential Current Feedback Operational Download Download this article. Language English Author Mahmut UN, Fırat KACAR Keywords All-pass filter, fully differential current feedback operational amplifier, integrator, quadrature oscillator, analog integrated circuits Abstract A novel voltage-mode first-order all-pass filter configuration is proposed. The presented circuit uses single fully differential current feedback operational amplifier (FDCFOA), resistors and capacitors.The output of the filter exhibits fully differential buffer circuit so that the synthesized filter can be cascaded without additional buffers. Furthermore the proposed circuit is suitable for wide range, low voltage and low power applications. To demostrate the performance of the proposed filter the voltage mode quadrature oscillators are given as an application example. They are implemented through the proposed FDCFOA based first order allpass filter and integrator as a building blocks. The theoretical results are verified with SPICE simulations using CMOS realization of FDCFOA.   13 Subject Research On μ Synthesis Based Hydroturbine Governor Design Download Download this article. Language English Author Feiyue HE, Xianzhong DUAN Keywords NCS; μ-synthesis; robust control; governor; time delay. Abstract A novel hydroturbine governor scheme based on networked control system (NCS) is proposed. The key problem of the scheme rest with the time delay existing in the data communication in NCS as the time delay may be a detriment to governor system stability and may degrade system robustness. In order to guarantee the governor system stable with time delay, the uncertain delay model is modeled as multiplicative perturbation, and a synthesis based robust governor is presented. The result verifies feasibility of the robust controller.   14 Subject Control Algorithm And Implementation Scheme Of UPFC In Laboratory Download Download this article. Language English Author Aihong TANG, Shijie CHENG Keywords UPFC, control, scheme design Abstract This paper analyzes the work principle of UPFC and describes its control algorithm. On these fundamental, proposals a corresponding control scheme for the implementation of UPFC in laboratory.   15 Subject The Performance Analysis Of STFT-ANFIS Classification Method On Pulsed Radar Target Categorization Download Download this article. Language English Author Engin AVCI, Ibrahim TURKOGLU, Mustafa POYRAZ Keywords Feature extraction, ANFIS, radar target classification, STFT. Abstract In this paper, a pattern recognition system is developed for automatic classification of the radar target signals. Feature extraction is an important subset of the pattern recognition system. For feature extraction is used Short Term Fourier Transform (STFT) time-frequency distribution of the pulse radar target signals. Adaptive Network Based Fuzzy Inference System (ANFIS) classifier is used at classifier part of the pattern recognition system. Radar signals are obtained from pulse radar system for various targets. The classifier performance is evaluated according to the proposal method.   16 Subject Performance Of Two Level Turbo Coded 4-Ary CPPSK Systems Over AWGN And Fading Channels Download Download this article. Language English Author Niyazi ODABASIOGLU Keywords Turbo coding, Multilevel coding, Continuous phase frequency shift keying Abstract This paper presents performance of two level turbo coded 4-ary continuous phase frequency shift keying. In this system,, to provide phase continuity of the transmitted signals, turbo encoder and continuous phase encoder (CPE) are serially concatenated at the second level, while first level consist of only a turbo encoder. Simulation results are drawn for proposed system over AWGN, Rician and Rayleigh channels for three iterations while frame sizes are chosen as 100 and 1024. High error performances are obtained for proposed system compared to Trellis Coded CPFSK system.   17 Subject A Short Note On The Application Of Cholesky Matrix Factorisation Using Matlab Download Download this article. Language English Author Ali Umit KESKIN, Imran GOKER Keywords Matrix Factorisation, Cholesky Algorithm, MATLAB. Abstract One must first make sure that a given matrix subject to factorization is symmetric, and then use it in Cholesky algorithm, in MATLAB. This may cost machine time to check for symmetry, however, saves much more of it by preventing errors due to inherent structure of the built-in algorithm.