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Articles 5431 - 5460 of 7211

Full-Text Articles in Computer Engineering

Comparison Study Of Computational Parameter Values Between Lrn And Narx In Identifying Nonlinear Systems, Farah Hani Nordin, Farrukh Hafiz Nagi, Aidil Azwin Zainul Abidin Jan 2013

Comparison Study Of Computational Parameter Values Between Lrn And Narx In Identifying Nonlinear Systems, Farah Hani Nordin, Farrukh Hafiz Nagi, Aidil Azwin Zainul Abidin

Turkish Journal of Electrical Engineering and Computer Sciences

To determine the nonlinear autoregressive model with exogenous inputs (NARX) parameter values is not an easy task, even though NARX is reported to successfully identify nonlinear systems. Apart from the activation functions, number of layers, layer size, learning rate, and number of epochs, the number of delays at the input and at the feedback loop need to also be determined. The layer recurrent network (LRN) is seen to have the potential to outperform NARX. However, not many papers have reported on using the LRN to identify nonlinear systems. Therefore, it is the aim of this paper to investigate and analyze …


Shape Control Of Cyclic Networks In Multirobot Formations, Tolga Eren Jan 2013

Shape Control Of Cyclic Networks In Multirobot Formations, Tolga Eren

Turkish Journal of Electrical Engineering and Computer Sciences

The first part of this paper examines cycles at the network level of sensing and control architectures that are needed to maintain the shape of a multiagent formation in 2-dimensional space, while the formation moves as a cohesive whole. The key tools used in the paper are rigidity theory and graph theory. The second part of the paper focuses on the planner level and controller level of the architecture by designing the fuzzy planner and fuzzy controller of individual agents. This permits the decomposition of the complex coordination problem into a series of smaller ones. The fuzzy planner and the …


An Automated Prognosis System For Estrogen Hormone Status Assessment In Breast Cancer Tissue Samples, Fati̇h Sarikoç, Adem Kalinli, Hülya Akgün, Fi̇gen Öztürk Jan 2013

An Automated Prognosis System For Estrogen Hormone Status Assessment In Breast Cancer Tissue Samples, Fati̇h Sarikoç, Adem Kalinli, Hülya Akgün, Fi̇gen Öztürk

Turkish Journal of Electrical Engineering and Computer Sciences

Estrogen receptor (ER) status evaluation is a widely applied method in the prognosis of breast cancer. However, testing for the existence of the ER biomarker in a patient's tumor sample mainly depends on the subjective decisions of the doctors. The aim of this paper is to introduce the usage of a machine learning tool, functional trees (FTs), to attain an ER prognosis of the disease via an objective decision model. For this aim, 27 image files, each of which came from a biopsy sample of an invasive ductal carcinoma patient, were scanned and captured by a light microscope. From these …


A Rule Induction Algorithm For Knowledge Discovery And Classification, Ömer Akgöbek Jan 2013

A Rule Induction Algorithm For Knowledge Discovery And Classification, Ömer Akgöbek

Turkish Journal of Electrical Engineering and Computer Sciences

Classification and rule induction are key topics in the fields of decision making and knowledge discovery. The objective of this study is to present a new algorithm developed for automatic knowledge acquisition in data mining. The proposed algorithm has been named RES-2 (Rule Extraction System). It aims at eliminating the pitfalls and disadvantages of the techniques and algorithms currently in use. The proposed algorithm makes use of the direct rule extraction approach, rather than the decision tree. For this purpose, it uses a set of examples to induce general rules. In this study, 15 datasets consisting of multiclass values with …


Topology And Control Design Of A Sinusoidal Very Low Frequency High Voltage Generator, Zhigang Liu, Guofeng Li, Ninghui Wang Jan 2013

Topology And Control Design Of A Sinusoidal Very Low Frequency High Voltage Generator, Zhigang Liu, Guofeng Li, Ninghui Wang

Turkish Journal of Electrical Engineering and Computer Sciences

To reduce the volume and the structural complexity of a very low frequency (VLF) high voltage (HV) generator, this paper introduces a novel sinusoidal VLF HV generator with 2 high frequency HV (HFHV) transformers and 2 metal-oxide semiconductor field-effect transistor cascaded HV bridge arms. Series-parallel resonant converter technology is applied to reduce the impact of the distributed parameters, decreasing the power loss and the volume of the transformer. Both the switching frequency and the duty cycle are utilized as actuating variables to cope with the large ranges of output. Simultaneously, the principle of segmental data processing is proposed to obtain …


Operational Characteristics Of A Filtering Rectifier Transformer For Industrial Power Systems, Zhiyu Zhao, Longfu Luo, Jiazhu Xu, Thanhngoc Tran, Zhiwen Zhang Jan 2013

Operational Characteristics Of A Filtering Rectifier Transformer For Industrial Power Systems, Zhiyu Zhao, Longfu Luo, Jiazhu Xu, Thanhngoc Tran, Zhiwen Zhang

Turkish Journal of Electrical Engineering and Computer Sciences

Many conventional methods focus on reducing the harmful impact of the poor power quality in industrial rectifier systems, but they focus more on the harmonic problems of the utility grid than they do on that of the rectifier transformer; hence, the rectifier transformer would still be adversely affected by harmonic pollution. In order to solve the problem, a filtering rectifier transformer is proposed that adopts a harmonic current drainage system that incorporates tertiary winding and tuned harmonic filters. The impedance of the tertiary winding is specially designed and the tuned harmonic filters work together to restrain the harmonic current and …


Unscented Transformation-Based Probabilistic Optimal Power Flow For Modeling The Effect Of Wind Power Generation, Morteza Aien, Mahmood Fotuhi-Firuzabad, Farrokh Aminifar Jan 2013

Unscented Transformation-Based Probabilistic Optimal Power Flow For Modeling The Effect Of Wind Power Generation, Morteza Aien, Mahmood Fotuhi-Firuzabad, Farrokh Aminifar

Turkish Journal of Electrical Engineering and Computer Sciences

The unprecedented increasing penetration of distributed energy resources, mainly harvesting renewable energies, is a direct result of environmental concerns. These types of energy resources bring about more uncertainties in the power system and, consequently, necessitate probabilistic analyses of the system performance. This paper develops a new approach for probabilistic optimal power flow (P-OPF) by adapting the unscented transformation (UT) method. The heart of the proposed method lies in how to produce the sampling points. Appropriate sample points are chosen to perform the P-OPF with a high degree of accuracy and less computational burden in comparison with the features of other …


Antiwindup Design For The Speed Loop Pi Controller Of A Pmsm Servo System, Ming Yang, Li Niu, Dian-Guo Xu Jan 2013

Antiwindup Design For The Speed Loop Pi Controller Of A Pmsm Servo System, Ming Yang, Li Niu, Dian-Guo Xu

Turkish Journal of Electrical Engineering and Computer Sciences

A novel antiwindup (AW) strategy for a proportional-integral (PI) regulator based on the back-calculation method is presented. The proposed method will calculate the gain of the back-calculation based on the input and output status of the PI regulator without the requirement of motor parameters, such as the inertial and torque-current coefficient, and the back-calculation gain will vary with the speed command in order to obtain the optimal dynamic performance. The proposed method avoids the problem caused by the fixed back-calculation gain in the classical AW strategy, and prevents the system from untimely saturation withdrawing or an unexpected overshoot due to …


Feature-Based Fault Detection Of Industrial Gas Turbines Using Neural Networks, Abbas Rasaienia, Behzad Moshiri, Mohammadamin Moezzi Jan 2013

Feature-Based Fault Detection Of Industrial Gas Turbines Using Neural Networks, Abbas Rasaienia, Behzad Moshiri, Mohammadamin Moezzi

Turkish Journal of Electrical Engineering and Computer Sciences

Gas turbine (GT) fault detection plays a vital role in the minimization of power plant operation costs associated with power plant overhaul time intervals. In other words, it is helpful in generating pre-alarms and paves the way for corrective actions in due time before incurring major equipment failures. Hence, finding an efficient fault detection technique that is applicable in the online operation of power plants involved with minor computations is an urgent need in the power generation industry. Such a method is studied in this paper for the V94.2 class of GTs. As the most leading stage for developing a …


Shifted-Modified Chebyshev Filters, Meti̇n Şengül Jan 2013

Shifted-Modified Chebyshev Filters, Meti̇n Şengül

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces a new type of filter approximation method that utilizes shifted-modified Chebyshev filters. Construction of the new filters involves the use of shifted-modified Chebyshev polynomials that are formed using the roots of conventional Chebyshev polynomials. The study also includes 2 tables containing the shifted-modified Chebyshev polynomials and the normalized element values for the low-pass prototype filters up to degree 6. The transducer power gain, group delay, and impulse and step responses of the proposed filters are compared with those of the Butterworth and Chebyshev filters, and a sixth-order filter design example is presented to illustrate the implementation of …


Big Bang-Big Crunch Optimization Algorithm With Local Directional Moves, Hakki Murat Genç, İbrahi̇m Eksi̇n, Osman Kaan Erol Jan 2013

Big Bang-Big Crunch Optimization Algorithm With Local Directional Moves, Hakki Murat Genç, İbrahi̇m Eksi̇n, Osman Kaan Erol

Turkish Journal of Electrical Engineering and Computer Sciences

The big bang--big crunch (BB--BC) algorithm has been proposed as a novel optimization method that relies on one of the theories of the evolution of the universe, namely the big bang and big crunch theory. It has been shown that this algorithm is capable of quick convergence, even in long, narrow parabolic-shaped flat valleys or in the existence of several local extremes. In this work, the BB--BC optimization algorithm is hybridized with local search moves in between the ``banging'' and ``crunching'' phases of the algorithm. These 2 original phases of the BB--BC algorithm are preserved, but the representative point (``best'' …


Lightweight Wireless Protocol Based On Ieee 802.11 For Delay Sensitive Telerobotic Systems, Onur Toker, Haluk Gümüşkaya, Ci̇han Ulaş, Bora Tamer Yilmaz Jan 2013

Lightweight Wireless Protocol Based On Ieee 802.11 For Delay Sensitive Telerobotic Systems, Onur Toker, Haluk Gümüşkaya, Ci̇han Ulaş, Bora Tamer Yilmaz

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we consider wireless telerobotic systems and protocol development for low-delay wireless communication. Telerobotics can be defined as the control of robot arms from a remote location. In a telerobotic system, there is a robot arm to be controlled that is identified as the `slave arm', and a remote operator at a distant location using a robotic manipulator that is called the `master arm'. In the control system measurements, actuator delays do degrade the system's performance. Therefore, communication delays between the master and slave arms, and their minimization, are of extreme importance in telerobotics. In this paper, we …


Efficient Feature Integration With Wikipedia-Based Semantic Feature Extraction For Turkish Text Summarization, Aysun Güran, Ni̇lgün Güler Bayazit, Mustafa Zahi̇d Gürbüz Jan 2013

Efficient Feature Integration With Wikipedia-Based Semantic Feature Extraction For Turkish Text Summarization, Aysun Güran, Ni̇lgün Güler Bayazit, Mustafa Zahi̇d Gürbüz

Turkish Journal of Electrical Engineering and Computer Sciences

This study presents a novel hybrid Turkish text summarization system that combines structural and semantic features. The system uses 5 structural features, 1 of which is newly proposed and 3 are semantic features whose values are extracted from Turkish Wikipedia links. The features are combined using the weights calculated by 2 novel approaches. The first approach makes use of an analytical hierarchical process, which depends on a series of expert judgments based on pairwise comparisons of the features. The second approach makes use of the artificial bee colony algorithm for automatically determining the weights of the features. To confirm the …


Review Of Distinctive Phonetic Features And The Arabic Share In Related Modern Research, Yousef Alotaibi, Ali Meftah Jan 2013

Review Of Distinctive Phonetic Features And The Arabic Share In Related Modern Research, Yousef Alotaibi, Ali Meftah

Turkish Journal of Electrical Engineering and Computer Sciences

Most research in the field of digital speech technology has traditionally been conducted in only a few languages, such as English, French, Spanish, or Chinese. Numerous studies using distinctive phonetic features (DPFs) with different techniques and algorithms have been carried out during the last 3 decades, mainly in English, Japanese, and other languages of industrialized countries. DPF elements are based on a technique used by linguists and digital speech and language experts to distinguish between different phones by considering the lowest level of actual features during phonation. These studies have investigated the best performances, outcomes, and theories, especially those regarding …


A Linearly Slotted Waveguide Antenna And Comparison Of It With A Sinusoidal One, Alp Oral Salman Jan 2013

A Linearly Slotted Waveguide Antenna And Comparison Of It With A Sinusoidal One, Alp Oral Salman

Turkish Journal of Electrical Engineering and Computer Sciences

A linearly slotted waveguide antenna (LSWA) is investigated. The slot is placed in one of the narrow faces of a rectangular waveguide, which operates at Ka-band (26.5--40 GHz), which is in a frequency range including upper microwaves and the lower edge of millimeter waves. Analytically, the magnetic current approach is applied. Some antenna parameters of this structure are experimentally measured and it is observed that the antenna radiates a single transversal-polarized beam that scans with frequency. The experimentally obtained patterns in 2 perpendicular planes are also correlated with analytical and numerical patterns that use the magnetic current model and HFSS, …


A Learning Approach In Link Adaptation For Mimo-Ofdm Systems, Hali̇l Yi̇ği̇t, Adnan Kavak Jan 2013

A Learning Approach In Link Adaptation For Mimo-Ofdm Systems, Hali̇l Yi̇ği̇t, Adnan Kavak

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a neural network (NN)-based adaptive modulation and coding (AMC) for link adaptation in MIMO-OFDM systems. The AMC optimizes the best modulation and coding scheme (MCS) under a packet error rate (PER) constraint. In our approach, a NN with a multilayer perceptron (MLP) structure is applied for the AMC and its performance is compared with the k-nearest neighbor (k-NN) algorithm under the frequency-flat (1-tap) and frequency-selective (4-tap) wireless channel conditions. The simulation results show that the NN classifier outperforms the k-NN algorithm, especially in terms of the PER, due to the fact that the MLP guarantees a MCS with …


Economic Power Dispatch Of Power Systems With Pollution Control Using Artificial Bee Colony Optimization, Linda Slimani, Tarek Bouktir Jan 2013

Economic Power Dispatch Of Power Systems With Pollution Control Using Artificial Bee Colony Optimization, Linda Slimani, Tarek Bouktir

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a solution for the emission-controlled economic dispatch (ECED) problem of medium-sized power systems via an artificial bee colony algorithm. The ECED problem, which accounts for the minimization of both the fuel cost and the emission, is a multiple objective function problem. The objective is to minimize the total fuel cost of the generation and environmental pollution caused by fossil-based thermal generating units and to also maintain an acceptable system performance in terms of the limits on the generator's real and reactive power outputs, bus voltages, shunt capacitors/reactors, and power flow of transmission lines. The proposed algorithm is …


Robust Sensorless Predictive Control Of Induction Motors With Sliding Mode Voltage Model Observer, Seyed Alireza Davari, Davood Arab Khaburi, Fengxiang Wang, Ralph Kennel Jan 2013

Robust Sensorless Predictive Control Of Induction Motors With Sliding Mode Voltage Model Observer, Seyed Alireza Davari, Davood Arab Khaburi, Fengxiang Wang, Ralph Kennel

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a robust sliding mode prediction model is combined with a sliding mode voltage model observer to achieve a sensorless predictive torque control method. In order to compensate the uncertainties of the stator and rotor resistances and the offset of measured current, sliding mode feedbacks were added to the voltage model observer. To reduce the effect of the errors that are injected from the observer to the prediction model in the sensorless application, the prediction model was also reinforced by a sliding mode feedback. The feedback gains for the prediction and observer models are assigned by a robustness …


Simulation Of Transient Processes On Overvoltage In Electric Transmission Lines Using Atp-Emtp, Ahmet Nayi̇r Jan 2013

Simulation Of Transient Processes On Overvoltage In Electric Transmission Lines Using Atp-Emtp, Ahmet Nayi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the mathematical modeling and simulation of electromagnetic transient processes is considered, which is of vital importance for examining the overvoltage phenomenon of power transmission systems. In the mathematical models of the AC power transmission systems that contain a power source, the power transformer, transmission line, and power autotransformer block are presented. The mathematical model of each system component is obtained based on the branch voltages, flux linkages, and branch voltages of the magnetic circuits individually. As for the simulation, an alternative transient program (ATP) environment is used to model the electric power system's elements. One of the …


High-Performance Cmos Cci In A 0.35 \Mu M Cmos Technology And A New All-Pass Filter Application, Emre Arslan, Bi̇lgi̇n Meti̇n, Mehmet Oğuzhan Çi̇çekoğlu, Avni̇ Morgül Jan 2013

High-Performance Cmos Cci In A 0.35 \Mu M Cmos Technology And A New All-Pass Filter Application, Emre Arslan, Bi̇lgi̇n Meti̇n, Mehmet Oğuzhan Çi̇çekoğlu, Avni̇ Morgül

Turkish Journal of Electrical Engineering and Computer Sciences

A differential pair-based, high-performance, first-generation current conveyor is proposed. The proposed circuit is laid out using the Mentor Graphics IC Station layout editor. The performance characteristics have been determined from HSpice postlayout simulations using the Austria Mikro Systeme 0.35 \mu m, 3.3 V process parameters. During the simulations, \pm 1.65 V supply voltages and a 25 \mu A biasing current are used. The power consumption is about 1.12 mW. The circuit also has very high voltage swings on ports X and Y, a very small impedance value on port X, high impedance values on ports Y and Z, and high-valued …


A Novel Uwb Cpw-Fed Ring-Shaped Antenna With Band-Notched Characteristics, Maryam Majidzadeh, Changiz Ghobadi Jan 2013

A Novel Uwb Cpw-Fed Ring-Shaped Antenna With Band-Notched Characteristics, Maryam Majidzadeh, Changiz Ghobadi

Turkish Journal of Electrical Engineering and Computer Sciences

A novel compact omnidirectional coplanar waveguide (CPW)-fed antenna with band-notched characteristics has been designed and analyzed. The proposed ultra-wideband (UWB) antenna has a simple structure. A ring-shaped radiating patch is excited by a CPW feed line. By creating 2 square slots on the top corners of the antenna, a new resonance is excited and the bandwidth is enhanced. The band-notched function is achieved by applying 2 rectangular stubs to the ground plane structure. The proposed antenna occupies a small size of 20 x 20 x 1 mm^3 and covers a wide frequency range of 3.1--14 GHz, except for 5--6 GHz, …


Opposition-Based Discrete Action Reinforcement Learning Automata Algorithm Case Study: Optimal Design Of A Pid Controller, Fatemeh Mohseni Pour, Ali Akbar Gharaveisi Jan 2013

Opposition-Based Discrete Action Reinforcement Learning Automata Algorithm Case Study: Optimal Design Of A Pid Controller, Fatemeh Mohseni Pour, Ali Akbar Gharaveisi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the discrete action reinforcement learning automata (DARLA) method is expressed. The performance of the reinforcement learning algorithm is improved using the opposite concepts. This is an automatic method that can find the global optima without any knowledge about the parameters of the research space. To find the global optimal point, the interval that contains the optima is determined by DARLA as the cost function is minimized. In the opposition-based DARLA method, learning is performed based on opposition. The main idea in the opposition is to consider the search direction and its opposite at the same time to …


Direct Adaptive Fuzzy Sliding Mode Decoupling Control For A Class Of Underactuated Mechanical Systems, Fares Nafa, Salim Labiod, Hachemi Chekireb Jan 2013

Direct Adaptive Fuzzy Sliding Mode Decoupling Control For A Class Of Underactuated Mechanical Systems, Fares Nafa, Salim Labiod, Hachemi Chekireb

Turkish Journal of Electrical Engineering and Computer Sciences

Motivated by the dynamic characteristics of underactuated mechanical systems with 2 degrees of freedom, a decoupling adaptive fuzzy sliding mode decoupling controller (DAFSMDC) is presented in this paper. By exploiting the universal approximation property of fuzzy logic systems and the sliding mode control method, this paper proposes a new decoupling strategy of the system into 2 second-order subsystems and introduces an adaptive control algorithm that guarantees the convergence of both subsystems. Since fuzzy systems are used to approximate an unknown ideal controller, the adjustable parameters of the used fuzzy systems are updated using a gradient descent algorithm that is designed …


Encoderless Position Estimation And Error Correction Techniques For Miniature Mobile Robots, Farshad Arvin, Masoud Bekravi Jan 2013

Encoderless Position Estimation And Error Correction Techniques For Miniature Mobile Robots, Farshad Arvin, Masoud Bekravi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an encoderless position estimation technique for miniature-sized mobile robots. Odometry techniques, which are based on the hardware components, are commonly used for calculating the geometric location of mobile robots. Therefore, the robot must be equipped with an appropriate sensor to measure the motion. However, due to the hardware limitations of some robots, employing extra hardware is impossible. On the other hand, in swarm robotic research, which uses a large number of mobile robots, equipping the robots with motion sensors might be costly. In this study, the trajectory of the robot is divided into several small displacements over …


Four-Dimensional Model For Describing The Status Of Peers In Peer-To-Peer Distributed Systems, Seyedeh Leili Mirtaheri, Ehsan Mousavi Khaneghah, Mohsen Sharifi, Behrouz Minaei-Bidgoli, Bijan Raahemi, Mohammad Norouzi Arab, Abbas Saleh Ardestani Jan 2013

Four-Dimensional Model For Describing The Status Of Peers In Peer-To-Peer Distributed Systems, Seyedeh Leili Mirtaheri, Ehsan Mousavi Khaneghah, Mohsen Sharifi, Behrouz Minaei-Bidgoli, Bijan Raahemi, Mohammad Norouzi Arab, Abbas Saleh Ardestani

Turkish Journal of Electrical Engineering and Computer Sciences

One of the important aspects of decision making and management in distributed systems is collecting accurate information about the available resources of the peers. The previously proposed approaches for collecting such information completely depend on the system's architecture. In the server-oriented architecture, servers assume the main role of collecting comprehensive information from the peers and the system. Next, based on the information about the features of the basic activities and the system, an exact description of the peers' status is produced. Accurate decisions are then made using this description. However, the amount of information gathered in this architecture is too …


Discrete Event Simulation-Based Performance Evaluation Of Internet Routing Protocols, Fati̇h Çeli̇k, Ahmet Zengi̇n, Bülent Çobanoğlu Jan 2013

Discrete Event Simulation-Based Performance Evaluation Of Internet Routing Protocols, Fati̇h Çeli̇k, Ahmet Zengi̇n, Bülent Çobanoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a discrete event system specification (DEVS)-based comparative performance analysis between the open shortest path first (OSPF) protocol and the routing information protocol (RIP), together with the border gateway protocol (BGP), using DEVS-Suite. In order to evaluate the OSPF and RIP's scalability performance, several network models are designed and configured with the OSPF and RIP, in combination with the BGP. Evaluations of the proposed routing protocols are performed based on the metrics, such as the execution time, convergence time, turnaround time, throughput, and efficiency across an increasing size and complexity through the simulated network models. The evaluation results …


Hybrid Of Genetic Algorithm And Great Deluge Algorithm For Rough Set Attribute Reduction, Najmeh Sadat Jaddi, Salwani Abdullah Jan 2013

Hybrid Of Genetic Algorithm And Great Deluge Algorithm For Rough Set Attribute Reduction, Najmeh Sadat Jaddi, Salwani Abdullah

Turkish Journal of Electrical Engineering and Computer Sciences

The attribute reduction problem is the process of reducing unimportant attributes from a decision system to decrease the difficulty of data mining or knowledge discovery tasks. Many algorithms have been used to optimize this problem in rough set theory. The genetic algorithm (GA) is one of the algorithms that has already been applied to optimize this problem. This paper proposes 2 kinds of memetic algorithms, which are a hybridization of the GA, with 2 versions (linear and nonlinear) of the great deluge (GD) algorithm. The purpose of this hybridization is to investigate the ability of this local search algorithm to …


A New Extension Of Activity Networks For Modeling And Verification Of Timed Systems, Hassan Motallebi, Mohammad Abdollahi Azgomi, Mohammad Saber Mirzaei, Ali Movaghar Jan 2013

A New Extension Of Activity Networks For Modeling And Verification Of Timed Systems, Hassan Motallebi, Mohammad Abdollahi Azgomi, Mohammad Saber Mirzaei, Ali Movaghar

Turkish Journal of Electrical Engineering and Computer Sciences

Stochastic activity networks (SANs) are a well-known petri net-based formalism used for the performance and dependability modeling of a wide range of systems. On the other hand, the growing complexity of timed systems makes it imperative to apply formal analysis techniques in the early stages of the system's development. Finding a suitable framework for the modeling, evaluation, and verification of these systems is still a great challenge. In this paper, we introduce a new formalism named timed activity networks (TANs), which are based on the activity networks that are the nondeterministic settings of the SANs. The advantages of TANs are …


Outlier Rejection Fuzzy C-Means (Orfcm) Algorithm For Image Segmentation, Fasahat Ullah Siddiqui, Nor Ashidi Mat Isa, Abid Yahya Jan 2013

Outlier Rejection Fuzzy C-Means (Orfcm) Algorithm For Image Segmentation, Fasahat Ullah Siddiqui, Nor Ashidi Mat Isa, Abid Yahya

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a fuzzy clustering-based technique for image segmentation. Many attempts have been put into practice to increase the conventional fuzzy c-means (FCM) performance. In this paper, the sensitivity of the soft membership function of the FCM algorithm to the outlier is considered and the new exponent operator on the Euclidean distance is implemented in the membership function to improve the outlier rejection characteristics of the FCM. The comparative quantitative and qualitative studies are performed among the conventional k-means (KM), moving KM, and FCM algorithms; the latest state-of-the-art clustering algorithms, namely the adaptive fuzzy moving KM , adaptive fuzzy …


An Improved Back Projection Imaging Algorithm For Subsurface Target Detection, Wentai Lei, Sheng Zeng, Jian Zhao, Qianzhe Wang, Jianxin Liu Jan 2013

An Improved Back Projection Imaging Algorithm For Subsurface Target Detection, Wentai Lei, Sheng Zeng, Jian Zhao, Qianzhe Wang, Jianxin Liu

Turkish Journal of Electrical Engineering and Computer Sciences

An improved back projection imaging algorithm for subsurface target detection is presented in this paper. Firstly, the characteristic of the scattering data at each time-delay curve in the traditional back projection imaging procedure is analyzed. Secondly, a weight factor is designed for each focal point and an improved back projection imaging algorithm is presented. Thirdly, the simulation of the improved imaging algorithm is processed. The imaging results of both the simulation data and the real ground penetrating radar data show the effectiveness of this imaging algorithm.