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

Engineering Commons™

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

Journal

Discipline
Institution
Keyword
Publication Year
Publication
File Type

Articles 21391 - 21420 of 27416

Full-Text Articles in Engineering

Optimal Fuzzy Load Frequency Controller With Simultaneous Auto-Tuned Membership Functions And Fuzzy Control Rules, Abas Ali Zamani, Ehsan Bijami, Farid Sheikholeslam, Bahram Jafrasteh Jan 2014

Optimal Fuzzy Load Frequency Controller With Simultaneous Auto-Tuned Membership Functions And Fuzzy Control Rules, Abas Ali Zamani, Ehsan Bijami, Farid Sheikholeslam, Bahram Jafrasteh

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an auto-tuned fuzzy load frequency controller (FLFC)-based artificial bee colony (ABC) algorithm is developed to quench the deviations in the frequency and tie-line power due to load disturbances in an interconnected power system. Optimal tuning of membership functions (MFs) and fuzzy control rules is very important to improve the design performance and achieve a satisfactory level of robustness for a particular operation. In this work, to reduce the fuzzy system design effort and take large parametric uncertainties into account, a new systematic and simultaneous tuning method is developed for designing MFs and fuzzy rules. For this, the …

Go to article

Btsql: Nested Bitemporal Relational Database Query Language, Canan Atay, Abdullah Uz Tansel Jan 2014

Btsql: Nested Bitemporal Relational Database Query Language, Canan Atay, Abdullah Uz Tansel

Turkish Journal of Electrical Engineering and Computer Sciences

A nested bitemporal relational data model and its query language are implemented. The bitemporal atom (BTA) is the fundamental construct to represent temporal data and it contains 5 components: a value, the lower and upper bounds of valid time, and the lower and upper bounds of the recoding time. We consider 2 types of data structures for storing BTAs: 1) string representation and 2) abstract data-type representation. We also develop a preprocessor for translating a bitemporal structured query language (BtSQL) statement into standard SQL statements. The BtSQL includes the select, insert, delete, and update statements of the SQL, extended for …

Go to article

Wireless Sensor Localization Using Enhanced Dv-Aoa Algorithm, Peter Brida, Juraj Machaj, Jozef Benikovsky Jan 2014

Wireless Sensor Localization Using Enhanced Dv-Aoa Algorithm, Peter Brida, Juraj Machaj, Jozef Benikovsky

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we deal with the improvement of the positioning accuracy of distance vector (DV)-based positioning algorithms, which use angular information DV- angle of arrival (AoA). This algorithm belongs to an ad-hoc positioning system. We focus on the improvement of the algorithm and its enhanced version is presented. The angular information of particular nodes is obtained and processed by the original algorithm; however, the final position estimation is determined by the proposed novel algorithm using only a subset of all intersections. We assign weights to the individual intersections according to their positions and the positions of the RNs. For …

Go to article

A Reduced Probabilistic Neural Network For The Classification Of Large Databases, Abdelhadi Lotfi, Abdelkader Benyettou Jan 2014

A Reduced Probabilistic Neural Network For The Classification Of Large Databases, Abdelhadi Lotfi, Abdelkader Benyettou

Turkish Journal of Electrical Engineering and Computer Sciences

The probabilistic neural network (PNN) is a special type of radial basis neural network used mainly for classification problems. Due to the size of the network after training, this type of network is usually used for problems with a small-sized training dataset. In this paper, a new training algorithm is presented for use with large training databases. Application to the handwritten digit database shows that the reduced PNN performs better than the standard PNN for all of the studied cases with a big gain in size and processing speed. This new type of neural network can be used easily for …

Go to article

Statistical Approach For Determining Impulse Breakdown Voltage Distribution Under Dc Sweep Voltage, Mehmet Demi̇r, Celal Koraşli Jan 2014

Statistical Approach For Determining Impulse Breakdown Voltage Distribution Under Dc Sweep Voltage, Mehmet Demi̇r, Celal Koraşli

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a comprehensive approach to the statistical characterization of impulse breakdown voltage under the effect of a DC sweep voltage. Several goodness-of-fit tests are applied to up-and-down test results obtained in the air-insulated rod-plane gap. Three distributions, normal, logistic, and Gumbel, are compared by means of the Kolmogorov--Smirnov goodness-of-fit test, and logistic distribution is also compared to 3-parameter Weibull distributions using the likelihood ratio test. Logistic distribution is found to be a possible alternative to normal and 3-parameter Weibull distributions.

Go to article

A Learning Method To Evaluate A Generation Company's Bidding Strategy In The Electricity Market, Shengjie Yang, Jiangang Yao Jan 2014

A Learning Method To Evaluate A Generation Company's Bidding Strategy In The Electricity Market, Shengjie Yang, Jiangang Yao

Turkish Journal of Electrical Engineering and Computer Sciences

In the electricity market, generation companies (GenCos) are usually faced with the problem of choosing a better bidding strategy. They often have to evaluate each possible strategy according to its potential reward. In a competitive market environment, the electricity price is stochastic and volatile, and the GenCo's mixed strategies also make the problem more complicated. In this paper, we model the market price with a Markov regime-switching model and propose the temporal difference learning method in the Markov decision process to approximate the expected reward over an infinite horizon. The simulations based on this method have achieved the evaluation of …

Go to article

Modeling And Simulation Of Deadbeat-Based Pi Controller In A Single-Phase H-Bridge Inverter For Stand-Alone Applications, Tow Leong Tiang, Dahaman Ishak Jan 2014

Modeling And Simulation Of Deadbeat-Based Pi Controller In A Single-Phase H-Bridge Inverter For Stand-Alone Applications, Tow Leong Tiang, Dahaman Ishak

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a deadbeat-based proportional-integral (PI) controller for a stand-alone single-phase voltage source inverter using a battery cell as the primary energy source. The inverter system is simulated in MATLAB/Simulink. It consists of a lead acid battery, third-order Butterworth low-pass DC filter and AC filter, H-bridge inverter, step-up transformer, and a variety of loads, as well as its sinusoidal pulse-width modulation (SPWM) deadbeat-based PI controller. In this paper, 2 simulation case studies are carried out, which are the abrupt load changes from a 400 W resistive load to a 500 W resistive load, and from a 400 W resistive …

Go to article

Hd-Mr: A New Algorithm For Number Recognition In Electrical Meters, Miguel Rodriguez, Geovanni Berdugo, Daladier Jabba, Maria Calle, Miguel Jimeno Jan 2014

Hd-Mr: A New Algorithm For Number Recognition In Electrical Meters, Miguel Rodriguez, Geovanni Berdugo, Daladier Jabba, Maria Calle, Miguel Jimeno

Turkish Journal of Electrical Engineering and Computer Sciences

Utility companies in developing countries employ analog electrical meters to determine consumption and bill their customers accordingly. Obtaining an accurate reading is an expensive and time-consuming process. High consumption levels of water, energy, or gas are fined by the government; thus, it is necessary to develop tools that allow users to be informed about their consumption in real time. This paper proposes a new number recognition algorithm named the Hausdorff distance for meter reading (HD-MR). Experiments prove that HD-MR can achieve a 99.9% recognition rate, even when recognized numbers are under rotation. The maximum recognition time is 31 ms; hence, …

Go to article

A Novel Sms Application With Gsm Control On Numerator Systems, Ali̇ Sarikaş, Zi̇ya Ekşi̇, Cüneyt Yücelbaş, Ali̇ Buldu Jan 2014

A Novel Sms Application With Gsm Control On Numerator Systems, Ali̇ Sarikaş, Zi̇ya Ekşi̇, Cüneyt Yücelbaş, Ali̇ Buldu

Turkish Journal of Electrical Engineering and Computer Sciences

Numerator systems are widely used in various fields, sorting, and structures to ensure regular functioning. They are used today in places such as banks and hospitals to minimize the time spent waiting in a queue, and various studies have been undertaken to achieve efficiency in the workplace. At the beginning of these studies, numerator systems, which have been integrated into the short message service (SMS) application, have been used efficiently. With this application, to supply the required information to the user in the fastest way, a numerator system is developed by utilizing radio frequency communications and the SMS message structure. …

Go to article

Adaptive Feedback Control For Linear Singular Systems, Azita Azarfar, Heydar Toossian Shandiz, Masoud Shafiee Jan 2014

Adaptive Feedback Control For Linear Singular Systems, Azita Azarfar, Heydar Toossian Shandiz, Masoud Shafiee

Turkish Journal of Electrical Engineering and Computer Sciences

An adaptive state feedback control approach for linear descriptor (or singular) systems is investigated in this paper, which makes the closed-loop dynamics of this class of systems regular, impulse-free, and stable. The proposed adaptive method is based on the Lyapunov theorem to ensure the admissibility of the descriptor system and it also provides the state tracking with the desired reference trajectory. First, a control law is generated to stabilize the equilibrium point of origin, and, after that, the method is extended to a state tracking controller. The presented controller not only gets the stable output tracking asymptotically but is also …

Go to article

A Web Laboratory Using Matlab Builder Ne For Computer Image Processing, Sezgi̇n Kaçar, Cüneyt Bayilmiş, Özdemi̇r Çeti̇n Jan 2014

A Web Laboratory Using Matlab Builder Ne For Computer Image Processing, Sezgi̇n Kaçar, Cüneyt Bayilmiş, Özdemi̇r Çeti̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Many various instruments are needed for computer image processing. These instruments are used for image restoration, analysis, etc. This paper presents a novel web laboratory based on MATLAB Builder NE with Web Figure, called ImageWeb, to facilitate computer image processing without needed technical information for users. The developed ImageWeb provides fundamental principles of image processing, including basic, compression, edge detection, filtering, optimization, and histogram processes, and so on. In addition, the usage of MATLAB Builder NE with MATLAB Web Figure provides high flexibility with visualization means such as zoom, rotate, and 3-dimensional view. Users can easily access ImageWeb using only …

Go to article

Analysis Of A Rule-Based Curriculum Plan Optimization System With Spearman Rank Correlation, Di̇dem Abi̇di̇n, Hafi̇ze Şen Çakir Jan 2014

Analysis Of A Rule-Based Curriculum Plan Optimization System With Spearman Rank Correlation, Di̇dem Abi̇di̇n, Hafi̇ze Şen Çakir

Turkish Journal of Electrical Engineering and Computer Sciences

In corporations, accurate planning should be applied to manage the in-service training task within an optimum time period and without hindering the working tempo of the employees. For this reason, it is better to consider the curriculum planning task as a timetabling problem. However, when the timetables are prepared manually, it may turn out to be a complicated and time-consuming problem. In this study, it is aimed to evaluate the results of software introduced previously, which seeks to find a solution to the curriculum planning problem of in-service training programs in corporations using a rule-based genetic algorithm (GA). The input …

Go to article

A New Approach In The Evaluation Of Hospital Information Systems, Güney Gürsel, Neşe Zayi̇m, Kemal Hakan Gülkesen, Ali̇ Ari̇foğlu, Osman Saka Jan 2014

A New Approach In The Evaluation Of Hospital Information Systems, Güney Gürsel, Neşe Zayi̇m, Kemal Hakan Gülkesen, Ali̇ Ari̇foğlu, Osman Saka

Turkish Journal of Electrical Engineering and Computer Sciences

Hospital information system (HIS) evaluation frameworks have largely been discussed in the literature. However, existing frameworks lack one important aspect: to what extent user expectations of HISs are met. In this study, user expectation data are collected by means of the 'expectation questionnaire'. The internal consistencies of the answers to the questionnaire are measured by Cronbach's alpha coefficient. Fuzzy logic methodologies are used to evaluate the expectation variables in the proposed evaluation framework. The evaluation variables are not represented in the results equally; they are reflected by the weights assigned by the users. Our proposed framework provides the overall degree …

Go to article

Concurrently Attuned Design Of A Wadc-Based Upfc Psdc And Multiinput Pss For Improving Power System Dynamic Performance, Yashar Hashemi, Rasool Kazemzadeh, Mohammad Reza Azizian, Ahmad Sadeghi Yazdankhah Jan 2014

Concurrently Attuned Design Of A Wadc-Based Upfc Psdc And Multiinput Pss For Improving Power System Dynamic Performance, Yashar Hashemi, Rasool Kazemzadeh, Mohammad Reza Azizian, Ahmad Sadeghi Yazdankhah

Turkish Journal of Electrical Engineering and Computer Sciences

A new controller design for a unified power flow controller (UPFC) for damping of power system swings, focusing on interarea modes, is described in this paper. The proposed controller is a dual-layer controller, where the first layer is derived from local signals and the second layer is supplied by global signals, as additional measuring information from suitable remote network locations, where swings are well observable. For damping of low-frequency swing in wide-area operation, since there is little system information in the active power as input of the conventional power system stabilizer (CPSS), the effectiveness of the CPSS is low. For …

Go to article

Current-Mode Universal Filter And Quadrature Oscillator Using Cdtas, Jie Jin, Chunhua Wang Jan 2014

Current-Mode Universal Filter And Quadrature Oscillator Using Cdtas, Jie Jin, Chunhua Wang

Turkish Journal of Electrical Engineering and Computer Sciences

A current differencing transconductance amplifier (CDTA)-based multiple-input single-output (MISO) current-mode universal filter and a quadrature oscillator (QO) are presented in this paper. The same circuit is used in the filter and oscillator, which only consists of 2 CDTAs and 2 capacitors. The universal filter can realize low-pass, high-pass, band-pass, band-stop, and all-pass biquad filter functions. With a slight modification of the filter, a new current-mode QO can be obtained easily. The natural frequency and quality factor of the filter and the conditions of oscillation and frequency of oscillation of the QO are all orthogonally adjustable through the bias currents of …

Go to article

Markovian Approach Applied To Reliability Modeling Of A Wind Farm, Mazaher Hajibashi, Akbar Ebrahimi Jan 2014

Markovian Approach Applied To Reliability Modeling Of A Wind Farm, Mazaher Hajibashi, Akbar Ebrahimi

Turkish Journal of Electrical Engineering and Computer Sciences

The exploitation of wind energy as a resource for generating electricity is going to make a leap forward. Large-scale wind farms (WFs) will be engaged with power systems in the near future and this will cause changes in the supply pattern. Wind speed has an intermittent behavior and the output power of a WF is highly variable, consistent with this fact. The Markov process could consider this characteristic of wind speed using the state transition rate probability matrix, an issue that is neglected when a probability distribution function is established to model the wind speed data. The adequacy indices of …

Go to article

Design And Implementation Of A Programmable High-Voltage Impulse Measurement System, Serkan Dedeoğlu, Serhat Yilmaz Jan 2014

Design And Implementation Of A Programmable High-Voltage Impulse Measurement System, Serkan Dedeoğlu, Serhat Yilmaz

Turkish Journal of Electrical Engineering and Computer Sciences

High-voltage impulses (HVIs) are produced under laboratory conditions in order to emulate actual internal (switching) and external (lightning, thunderbolt) voltages. HVI resistance tests are essential to meet national and international standards on the production of electromechanical devices and materials, such as switchgears, and transformers that operate under these actual conditions. Accurate measurement of HVI is excessively difficult since the voltage level is so high, while the time parameters are relatively constricted. In this study, a reliable automatic HVI measuring and recording system, which accommodates a series of hardware and software designs in order to satisfy the constraints of the standards, …

Go to article

Design Of A Double-Stator Linear Switched Reluctance Motor For Shunting Railway Channels, El Manaa Barhoumi, Mansour Hajji, Boujemaa Ben Salah Jan 2014

Design Of A Double-Stator Linear Switched Reluctance Motor For Shunting Railway Channels, El Manaa Barhoumi, Mansour Hajji, Boujemaa Ben Salah

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents the design and modeling of a double-stator linear switched reluctance motor for motorizing a railway channels' shunting system. The magnetic behavior of this actuator is nonlinear due to the saturation and nonlinear magnetization curves of the materials used in this actuator. For this reason, the electromagnetic quantities such as force, flux linkage, and inductance are calculated with the finite element method using the Maxwell tool. The obtained results are presented and discussed. In order to elaborate some control strategies, a new model for the proposed actuator, based on the flux and force characteristics, is validated by the …

Go to article

A Novel Approach Based On Reliability Sensitivity Analysis To Allocate Protective Devices, Hamed Hashemi Dezaki, Hossein Askarian Abyaneh, Mehdi Garmrudi, Hossein Mahdinia, Kazem Mazlumi Jan 2014

A Novel Approach Based On Reliability Sensitivity Analysis To Allocate Protective Devices, Hamed Hashemi Dezaki, Hossein Askarian Abyaneh, Mehdi Garmrudi, Hossein Mahdinia, Kazem Mazlumi

Turkish Journal of Electrical Engineering and Computer Sciences

In electrical distribution systems, it is possible to have a reliable system via a well-designed protective scheme. The allocation of protective devices is an important parameter in the design of a protective scheme. Different approaches to optimize the allocation of protective devices have been studied. Because of some uncertainties, it is not the best strategy to select an optimized solution in accordance with certain conditions. The availability of the protective devices seriously affects the reliability of electrical distribution systems. Furthermore, reduction of the investment in some designing processes leads to a decrease in the number of protective devices that will …

Go to article

Observer-Based Controller For Current Mode Control Of An Interleaved Boost Converter, Shenbaga Lakshmi, Sree Renga Raja Jan 2014

Observer-Based Controller For Current Mode Control Of An Interleaved Boost Converter, Shenbaga Lakshmi, Sree Renga Raja

Turkish Journal of Electrical Engineering and Computer Sciences

A state feedback control method for an interleaved boost power converter is designed, which, in turn, can achieve interleaved current sharing among parallel-connected converters. The state feedback control in the continuous time domain is derived using the pole placement technique and linear quadratic optimal method. The load estimator is designed by deriving a full-order state observer to ensure the robustness and optimality of the state feedback control and an observer-based controller (control law plus full-order state observer) is designed using the separation principle. The adopted control strategies achieve effective output voltage regulation, good dynamic stability, and reject disturbances. Extensive simulation …

Go to article

Passive Ac Network Supplying The Integration Of Ccc-Hvdc And Vsc-Hvdc Systems, Ali Bidadfar, Mehrdad Abedi, Mehdi Karrari, Gevorg .Babamalek Gharehpetian, Sanaz Namayan Tavana Jan 2014

Passive Ac Network Supplying The Integration Of Ccc-Hvdc And Vsc-Hvdc Systems, Ali Bidadfar, Mehrdad Abedi, Mehdi Karrari, Gevorg .Babamalek Gharehpetian, Sanaz Namayan Tavana

Turkish Journal of Electrical Engineering and Computer Sciences

The integration of a capacitor-commutated converter (CCC) high-voltage direct current (HVDC) (CCC-HVDC) and voltage source converter (VSC) HVDC (VSC-HVDC) is proposed in this paper to supply entirely passive AC networks. The key point of this integration is the flat characteristic of the DC voltage of the CCC-HVDC, which provides the condition for the VSC to connect to the CCC DC link via a current regulator. The advantages of the proposed combined infeeding system are the requirement of only one DC line, and better dynamic responses. The structure of the proposed infeeding system, as well as its control system, is studied. …

Go to article

Luenberger Observer-Based Sensor Fault Detection: Online Application To Dc Motor, Alkan Alkaya, İlyas Eker Jan 2014

Luenberger Observer-Based Sensor Fault Detection: Online Application To Dc Motor, Alkan Alkaya, İlyas Eker

Turkish Journal of Electrical Engineering and Computer Sciences

Fault detection and diagnosis (FDD) are very important for engineering systems in industrial applications. One of the most popular approaches is model-based fault detection. Recently, many techniques have been proposed in the FDD area. However, there are still very few reported applications or real-time implementations of the schemes. This paper presents online sensor FDD based on the model-based approach using a Luenberger observer and experimental application on a permanent magnet DC motor. Different kinds of faults are simulated on the motor and experiments are performed to detect the faults. The experimental results demonstrate that this approach could significantly detect the …

Go to article

A Convergent Algorithm For A Cascade Network Of Multiplexed Dual Output Discrete Perceptrons For Linearly Nonseparable Classification, İbrahi̇m Genç, Cüneyt Güzeli̇ş Jan 2014

A Convergent Algorithm For A Cascade Network Of Multiplexed Dual Output Discrete Perceptrons For Linearly Nonseparable Classification, İbrahi̇m Genç, Cüneyt Güzeli̇ş

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a new discrete perceptron model is introduced. The model forms a cascade structure and it is capable of realizing an arbitrary classification task designed by a constructive learning algorithm. The main idea is to copy a discrete perceptron neuron's output to have a complementary dual output for the neuron, and then to select, by using a multiplexer, the true output, which might be 0 or 1 depending on the given input. Hence, the problem of realization of the desired output is transformed into the realization of the selector signal of the multiplexer. In the next step, the …

Go to article

Motion Clustering On Video Sequences Using A Competitive Learning Network, Sali̇h Görgünoğlu, Şafak Altay Jan 2014

Motion Clustering On Video Sequences Using A Competitive Learning Network, Sali̇h Görgünoğlu, Şafak Altay

Turkish Journal of Electrical Engineering and Computer Sciences

It is necessary to track human movements in crowded places and environments such as stations, subways, metros, and schoolyards, where security is of great importance. As a result, undesired injuries, accidents, and unusual movements can be determined and various precautionary measures can be taken against them. In this study, real-time or existing video sequences are used within the system. These video sequences are obtained from objects such as humans or vehicles, moving actively in various environments. At first, some preprocesses are made respectively, such as converting gray scale, finding the edges of the objects existing in the images, and thresholding …

Go to article

How Do Hccmes Perform In Small Samples?, Mehmet Orhan, Esra Şi̇mşek Jan 2014

How Do Hccmes Perform In Small Samples?, Mehmet Orhan, Esra Şi̇mşek

Turkish Journal of Electrical Engineering and Computer Sciences

The purpose of this paper is to explore the performances of prominent and popular heteroscedasticity-consistent covariance matrix estimators (HCCMEs) in small samples. The HCCMEs are selected from the literature and their ability to estimate the true covariance matrix of the coefficient's vector is evaluated through simulation runs. We calculate the percentage difference between the expected value of the HCCME and the true covariance matrix to set a convenient stage to make the comparisons under several different regression settings. The main contribution of the paper is the inclusion of the HCCMEs that have been introduced into the literature recently. We report …

Go to article

Early Wakeup: Improving The Drowsy Cache Performance, Sunghoon Shim, Sungwoo Chung, Hongjun Choi, Cheol Hong Kim Jan 2014

Early Wakeup: Improving The Drowsy Cache Performance, Sunghoon Shim, Sungwoo Chung, Hongjun Choi, Cheol Hong Kim

Turkish Journal of Electrical Engineering and Computer Sciences

As process technology scales down, leakage power consumption becomes comparable to dynamic power consumption. The drowsy cache technique is known as one of the most popular techniques for reducing the leakage power consumption in the data cache. However, the drowsy cache is reported to degrade the processor performance significantly. In this paper, to maintain the performance of the processor with the drowsy cache technique, we propose an early wakeup technique, which predicts the next cache line to be requested by utilizing the way-prediction information. The proposed technique efficiently reduces the number of accesses to the cache lines in drowsy mode. …

Go to article

Privacy Preserving In Association Rules Using A Genetic Algorithm, Rahat Ali Shah, Sohail Asghar Jan 2014

Privacy Preserving In Association Rules Using A Genetic Algorithm, Rahat Ali Shah, Sohail Asghar

Turkish Journal of Electrical Engineering and Computer Sciences

Association rule mining is one of the data mining techniques used to extract hidden knowledge from large datasets. This hidden knowledge contains useful and confidential information that users want to keep private from the public. Similarly, privacy preserving data mining techniques are used to preserve such confidential information or restrictive patterns from unauthorized access. The pattern can be represented in the form of a frequent itemset or association rule. Furthermore, a rule or pattern is marked as sensitive if its disclosure risk is above a given threshold. Numerous techniques have been used to hide sensitive association rules by performing some …

Go to article

Feature Selection On Single-Lead Ecg For Obstructive Sleep Apnea Diagnosis, Hüseyi̇n Gürüler, Mesut Şahi̇n, Abdullah Feri̇koğlu Jan 2014

Feature Selection On Single-Lead Ecg For Obstructive Sleep Apnea Diagnosis, Hüseyi̇n Gürüler, Mesut Şahi̇n, Abdullah Feri̇koğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Many articles that appeared in the literature agreed upon the feasibility of diagnosing obstructive sleep apnea (OSA) with a single-lead electrocardiogram. Although high accuracies have been achieved in detection of apneic episodes and classification into apnea/hypopnea, there has not been a consensus on the best method of selecting the feature parameters. This study presents a classification scheme for OSA using common features belonging to the time domain, frequency domain, and nonlinear calculations of heart rate variability analysis, and then proposes a method of feature selection based on correlation matrices (CMs). The results show that the CMs can be utilized in …

Go to article

Vessel Segmentation In Mri Using A Variational Image Subtraction Approach, Ayşe Nurdan Saran, Fati̇h Nar, Murat Saran Jan 2014

Vessel Segmentation In Mri Using A Variational Image Subtraction Approach, Ayşe Nurdan Saran, Fati̇h Nar, Murat Saran

Turkish Journal of Electrical Engineering and Computer Sciences

Vessel segmentation is important for many clinical applications, such as the diagnosis of vascular diseases, the planning of surgery, or the monitoring of the progress of disease. Although various approaches have been proposed to segment vessel structures from 3-dimensional medical images, to the best of our knowledge, there has been no known technique that uses magnetic resonance imaging (MRI) as prior information within the vessel segmentation of magnetic resonance angiography (MRA) or magnetic resonance venography (MRV) images. In this study, we propose a novel method that uses MRI images as an atlas, assuming that the patient has an MRI image …

Go to article

Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel Jan 2014

Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel

Turkish Journal of Electrical Engineering and Computer Sciences

One of the main sources of uncertainties in controlling the attitude of a satellite is the time delays seen in sensor data. Although it is possible to process sensor data to correct the deficiencies caused by delays, it is more suitable to design the controller robust enough to handle uncertainties well. In this study, the attitude of a 3-degrees of freedom satellite model, incorporating uncertainties (both sensor data delay and actuator misplacements), is controlled using a suitably designed fuzzy variable structure controller (FVSC). The performance of the FVSC is evaluated and compared to that of other reference controllers [proportional-derivative (PD), …

Go to article

First Prev Next Last