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- Classification (66)
- Deep learning (61)
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- Genetic algorithm (57)
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- Particle swarm optimization (49)
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- Support vector machine (34)
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Articles 2911 - 2940 of 3020
Full-Text Articles in Physical Sciences and Mathematics
Implementation Of A New Self-Tuning Fuzzy Pid Controller On Plc, Onur Karasakal, Engi̇n Yeşi̇l, Müjde Güzelkaya, İbrahi̇m Eksi̇n
Implementation Of A New Self-Tuning Fuzzy Pid Controller On Plc, Onur Karasakal, Engi̇n Yeşi̇l, Müjde Güzelkaya, İbrahi̇m Eksi̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, the self-tuning method for fuzzy PID controllers that has been developed in a previous study of the authors is implemented on PLC in order to control some standard processes formed on FEEDBACK PCS 327 Process Control Simulator. In this tuning method, the input scaling factor corresponding to the derivative coefficient and the output scaling factor corresponding to the integral coefficient of the fuzzy PID controller are adjusted using a fuzzy inference mechanism with a new input called ``normalized acceleration''. The results of the implementation have been compared with those of the classical fuzzy PID controller without a …
Mining Classification Rules By Using Genetic Algorithms With Non-Random Initial Population And Uniform Operator, Korkut Koray Gündoğan, Bi̇lal Alataş, Ali̇ Karci
Mining Classification Rules By Using Genetic Algorithms With Non-Random Initial Population And Uniform Operator, Korkut Koray Gündoğan, Bi̇lal Alataş, Ali̇ Karci
Turkish Journal of Electrical Engineering and Computer Sciences
Classification is a supervised learning method that induces a classification model from a database and is one of the most commonly applied data mining task. The frequently employed techniques are decision tree or neural network-based classification algorithms. This work presents an efficient genetic algorithm (GA) for classification rule mining technique that discovers comprehensible IF-THEN rules using a generalized uniform population method and a uniform operator inspired from the uniform population method. Initial population is generated by methodically eliminating the randomness by generalized uniform population method. In the subsequence generations, genetic diversity is ensured and premature convergence is prevented by the …
A Platform For Software Engineering Course Projects, Bi̇rol Aygün
A Platform For Software Engineering Course Projects, Bi̇rol Aygün
Turkish Journal of Electrical Engineering and Computer Sciences
The importance of projects in software engineering courses is well known. Both synthetic and real-life projects have various advantages and disadvantages. Our aim was to create a framework where students can develop projects which reflect some of the complexities of real-life, involving many concurrent, interacting, asynchronous processes, each in a different stage of development, with wide temporal differences among them - some occurring within millisconds of each other and others executing sporadically over much longer periods. In this project, which was carried out in different arrangements in several software engineering courses in three universities, the students developed both the sub- …
Optimum And Suboptimum Blind Channel And Symbol Estimation For Siso Channels, T. Engi̇n Tuncer
Optimum And Suboptimum Blind Channel And Symbol Estimation For Siso Channels, T. Engi̇n Tuncer
Turkish Journal of Electrical Engineering and Computer Sciences
We present three methods for blind channel and symbol identification from a single or multi-block observation. These methods are deterministic approaches suitable for the identification of quickly changing wireless channels. The first method uses the finite alphabet property and it has good performance even for noisy observations. It requires only a single data frame, which is a unique feature of the method. This method can also be used to identify the channel order. For multi-block observations, we present the maximal ratio combining cross relation (MRCCR) method. It is an optimum approach in terms of instantaneous SNR and is based on …
Neural Analysis Of Top Shielded Multilayered Coplanar Waveguides, Mustafa Türkmen, Celal Yildiz, Şeref Sağiroğlu
Neural Analysis Of Top Shielded Multilayered Coplanar Waveguides, Mustafa Türkmen, Celal Yildiz, Şeref Sağiroğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Artificial neural networks (ANNs) have been promising tools for many applications. In recent years, a computer-aided design approach based on (ANNs) has been introduced to microwave modelling, simulation and optimization. In this work, the characteristic parameters of top shielded multilayered coplanar waveguides (CPWs) have been determined with the use of ANN models. These neural models were trained with Levenberg-Marquardt, resilient propagation, Bayesian regulation, quasi-Newton, and backpropagation learning algorithms. Better performance and learning speed with a simpler structure were achieved from these models. The results have shown that the estimated characteristic parameters are in very good agreement with the computed results …
An Implicit Surface Modeling Technique Based On A Modular Neural Network Architecture, Manuel Carcenac
An Implicit Surface Modeling Technique Based On A Modular Neural Network Architecture, Manuel Carcenac
Turkish Journal of Electrical Engineering and Computer Sciences
Independently from artificial intelligence applications, an artificial neural network can be viewed as a powerful tool for function reconstruction. Previous papers used this property to model an implicit surface out of some control points by reconstructing its underlying scalar field. Such an approach requests the neural network to memorize the control points, which has turned problematic for complex surfaces. In our paper, we show that this problem can be efficiently tackled by adapting the architecture of the neural network to the features compounding the surface: by learning first these features independently and then blending them gradually together, our modular architecture …
Real-Time Classification Algorithm For Recognition Of Machine Operating Modes By Use Of Self-Organizing Maps, Gancho Vachkov, Yuhiko Kiyota, Koji Komatsu, Satoshi Fujii
Real-Time Classification Algorithm For Recognition Of Machine Operating Modes By Use Of Self-Organizing Maps, Gancho Vachkov, Yuhiko Kiyota, Koji Komatsu, Satoshi Fujii
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper a new algorithm for classification and real-time recognition of different a-priorily assumed operating modes for construction machines is proposed. This algorithm utilizes the effectiveness of the Self-Organizing Maps (SOM) for creating the so called Separation Models, that are able to distinguish each operating mode separately. After training, these models are used in a real-time procedure, which calculates at each sampling time the minimal Euclidean distances from the current data point to a certain node of each SOM. Then the separation model (represented by a respective SOM) that has the least minimal distance to this data point defines …
A Simple And Global Optimization Algorithm For Engineering Problems: Differential Evolution Algorithm, Dervi̇ş Karaboğa, Selçuk Ökdem
A Simple And Global Optimization Algorithm For Engineering Problems: Differential Evolution Algorithm, Dervi̇ş Karaboğa, Selçuk Ökdem
Turkish Journal of Electrical Engineering and Computer Sciences
Differential Evolution (DE) algorithm is a new heuristic approach mainly having three advantages; finding the true global minimum regardless of the initial parameter values, fast convergence, and using few control parameters. DE algorithm is a population based algorithm like genetic algorithms using similar operators; crossover, mutation and selection. In this work, we have compared the performance of DE algorithm to that of some other well known versions of genetic algorithms: PGA, Grefensstette, Eshelman. In simulation studies, De Jong's test functions have been used. From the simulation results, it was observed that the convergence speed of DE is significantly better than …
The 7 C'S For Creating Living Software: A Research Perspective For Quality-Oriented Software Engineering, Mehmet Akşi̇t
The 7 C'S For Creating Living Software: A Research Perspective For Quality-Oriented Software Engineering, Mehmet Akşi̇t
Turkish Journal of Electrical Engineering and Computer Sciences
This article proposes the 7 C's for realizing quality-oriented software engineering practices. All the desired qualities of this approach are expressed in short by the term living software. The 7 C's are: Concern-oriented processes, Canonical models, Composable models, Certifiable models, Constructible models, Closure property of models and Controllable models. Each C is explained by the help of a set of definitions, a short overview of the background work and the problems that software engineers may experience in realizing the corresponding C. Further, throughout the article, a software development example is presented for illustrating the realization of the 7 C's. Finally, …
An Information System For Streamlining Software Development Process, Serkan Nalbant
An Information System For Streamlining Software Development Process, Serkan Nalbant
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper an information system to be employed by software development organizations is proposed, which automates software development process. The proposed system aims to lower cost, improve schedule performance and enhance quality of the software projects by the means of automation and unifying of operational information. The characteristics of the proposed system are described. Furthermore, its use is illustrated via the explanation of an exemplary software system called PACE that serves as an information system for planning, controlling, measuring and improving software development process and projects. The relationship of PACE with Software Capability Maturity Model (CMM) is also provided.
A Pattern Based Approach To Web Design Formalization, Ahmet Sikici, Yasemi̇n Topaloğlu
A Pattern Based Approach To Web Design Formalization, Ahmet Sikici, Yasemi̇n Topaloğlu
Turkish Journal of Electrical Engineering and Computer Sciences
World Wide Web is a global information network that affects many fields of our lives. The distributed, interlinked, visual and heterogeneous structure of the web makes it an irregular development environment. In this paper we propose a pattern based approach for increasing the effectiveness of development for the Web environment. This approach is based on the representation of the core meaning of each design as a set of patterns and requires the formulation of abstract solutions in a mathematical precision. This way not only reusable design experience will be codified unambiguously, but a smooth transition between the design and implementation …
An Agile Information Systems Development Method In Use, Mehmet Nafi̇z Aydin, Frank Harmsen, Kees Van Slooten, Robert Stegwee
An Agile Information Systems Development Method In Use, Mehmet Nafi̇z Aydin, Frank Harmsen, Kees Van Slooten, Robert Stegwee
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, agile information systems development methods, agile methods in short, have got considerable attention from practitioners. One of the reasons seems that agile methods, to some degree, can be adaptable to different project situations. However, little empirical research has been conducted on this subject. The major goal of this research is to identify which aspects of agile methods are perceived as most critical and difficult to realize and how such aspects are adapted in practice. To reach this goal we studied the working practices concerning the adaptation of an agile method in the IT department of one of the leading …
A Robustness Analysis Of Game-Theoretic Cdma Power Control, Xingzhe Fan, Murat Arcak, John T. Wen
A Robustness Analysis Of Game-Theoretic Cdma Power Control, Xingzhe Fan, Murat Arcak, John T. Wen
Turkish Journal of Electrical Engineering and Computer Sciences
This paper studies robustness of a gradient-type CDMA uplink power control algorithm with respect to disturbances and time-delays. This problem is of practical importance because unmodeled secondary interference effects from neighboring cells play the role of disturbances, and propagation delays are ubiquitous in wireless data networks. We first show L_p-stability, for p \in [1,\infity], with respect to additive disturbances. We pursue L_{\infity}-stability within the input-to-state stability (ISS) framework of Sontag [7], which makes explicit the vanishing effect of the initial conditions. Next, using the ISS property and a loop transformation, we prove that global asymptotic stability is preserved for sufficiently …
Global Stability Analysis Of An End-To-End Congestion Control Scheme For General Topology Networks With Delay, Tansu Alpcan, Tamer Başar
Global Stability Analysis Of An End-To-End Congestion Control Scheme For General Topology Networks With Delay, Tansu Alpcan, Tamer Başar
Turkish Journal of Electrical Engineering and Computer Sciences
We analyze the stability properties of an end-to-end congestion control scheme under fixed heterogeneous delays, and for general network topologies. The scheme analyzed is based on the congestion control game of [1], with the starting point being the unique Nash equilibrium of that game. We prove global stability of this solution (and hence of the congestion control algorithm) under a mild symmetricity condition. We further demonstrate the stability of the algorithm numerically for various delays, user numbers, and topologies
Flow Controller Design And Performance Analysis For Self-Similar Network Traffic, Peng Yan
Flow Controller Design And Performance Analysis For Self-Similar Network Traffic, Peng Yan
Turkish Journal of Electrical Engineering and Computer Sciences
Recent studies of high-resolution traffic measurement discovered the self-similarity in both LAN and WAN traffic. In this paper, we introduce a two-degree of freedom rate based flow controller, which includes a robust H^{\infity} control block and an LMMSE based capacity predictor. The former part can guarantee the robust stability against time-varying time delay uncertainties and the latter improves the transient response by predicting the self-similar cross-traffic. Implementation issues are discussed and performance analysis is provided to validate our design. We also investigate the prediction and control in larger time scale which is more applicable for the real network environment
Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n
Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In passive coherent locators (PCL) systems, noise and the precision of direction of arrival (DOA) estimation are key issues. This paper addresses the implementation of high-resolution DOA estimation methods, in particular the multiple signal classification (MUSIC) algorithm, the conventional beam forming (CBF) algorithm, and the algebraic constant modulus algorithm (ACMA). The goal is to compare the ACMA to the MUSIC and CBF algorithms for application to PCL. The results and analysis presented here support the use of constant modulus information, where available, as an important addition to DOA estimation. The ACMA offers many simple solutions to noise and separation related …
A Full Adaptive Observer For Dc Servo Motors, Ata Sevi̇nç
A Full Adaptive Observer For Dc Servo Motors, Ata Sevi̇nç
Turkish Journal of Electrical Engineering and Computer Sciences
An adaptive observer estimating all parameters and load torque is proposed for DC servo motors. The observer uses no direct feedback but the adaptation schemes use current and speed measurements. Both the observer and adaptations are simple to implement for real-time applications. Simulation results are satisfactory for the full adaptive observer. If the observer works in parallel with only load torque and armature resistance adaptations, the results are very good even if very low-quality sensors are used. In this simulation, only a single hall sensor is used as a rotational transducer, which produces a single pulse per revolution, and very …
New Infratechnologies In The Deregulated Power Sector, Jordan Shikoski, Vladimir Katic, Risto Rechkoski
New Infratechnologies In The Deregulated Power Sector, Jordan Shikoski, Vladimir Katic, Risto Rechkoski
Turkish Journal of Electrical Engineering and Computer Sciences
This paper discusses new infratechnologies in the deregulated power sector. Most measurement and standardization techniques can be viewed as infratechnology. Infratechnologies are technical tools, including the measurement of data, test methods, and practices and technique. Standardization requirements are related to the measurement requirement. Although the system operation and market transactions concern many import aspects, they are insupportable and often complementary. This distinction between the technical and market information is important because the characteristics of information needs and the impact on economic efficiency and clean power are generally different. The present paper focuses on infratechnologies that can potentially increase the benefits …
Initiatory Electrons In Compressed Gases In Positive Polarity, Mohammed Messaad, Mustapha Tioursi
Initiatory Electrons In Compressed Gases In Positive Polarity, Mohammed Messaad, Mustapha Tioursi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper deals with the nature of seed electron sources in compressed N_2 for positive polarity. We present an experimental procedure that provides evidence of the fact that collisional detachment from negative ions plays the most important role in the supply of seed electrons. Conditioning phenomena in compressed SF_6, N_2 and air have been simulated under positive lightning impulses for point-plane geometry.
Network Traffic Properties Of Bimodal Multicast Protocol, Öznur Özkasap, Mi̇ne Çağlar
Network Traffic Properties Of Bimodal Multicast Protocol, Öznur Özkasap, Mi̇ne Çağlar
Turkish Journal of Electrical Engineering and Computer Sciences
The popularity of large-scale distributed applications, such as videoconferencing, multimedia dissemination, electronic stock exchange and distributed cooperative work, has grown with the availability of high-speed networks and the expansion of the Internet. The key property of this type of applications is the need to distribute data among multiple participants together with an application-specific quality of service needs. This fact makes scalable multicast protocols an essential underlying communication structure. Although there exist several studies investigating the traffic characteristics of unicast communication, multicast traffic has not been examined extensively in previous studies. It is well known that the aggregate traffic properties of …
The \Mathcal{H}_\Infty Model Matching Problem With One Degree Of Freedom Static State Feedback, Murat Akin, Ati̇lla Bi̇r
The \Mathcal{H}_\Infty Model Matching Problem With One Degree Of Freedom Static State Feedback, Murat Akin, Ati̇lla Bi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper is to develop a new approach for a solution of the continuous-time model matching problem by a static state feedback in the sense of \mathcal{H}_\infty optimality criterion by using Linear Matrix Inequalities (LMIs). The main contribution could briefly be described as to reformulate the model matching problem in LMI formulation, to present the solvability conditions and to give a design procedure for the one degree of freedom static state feedback control law. Finally, the results are applied to an example system.
New Approaches For On-Line Tuning Of The Linear Sliding Surface Slope In Sliding Mode Controllers, Sezai̇ Tokat, İbrahi̇m Eksi̇n, Müjde Güzelkaya
New Approaches For On-Line Tuning Of The Linear Sliding Surface Slope In Sliding Mode Controllers, Sezai̇ Tokat, İbrahi̇m Eksi̇n, Müjde Güzelkaya
Turkish Journal of Electrical Engineering and Computer Sciences
The main objective of this study is to propose new approaches for on-line tuning of the linear sliding surface slope in sliding mode controllers. The new approaches are developed for a class of second order systems on new coordinate axes, one of which is the classical sliding surface and the other one is naturally chosen to be orthogonal to it. The control input of the sliding mode control law is then modified accordingly by applying the Lyapunov stability condition. The adjustment of the linear sliding surface slope defined in the new coordinate axes is achieved by tuning a new parameter …
Improving The Security And Flexibility Of One-Time Passwords By Signature Chains, Kemal Biçakci, Nazi̇fe Baykal
Improving The Security And Flexibility Of One-Time Passwords By Signature Chains, Kemal Biçakci, Nazi̇fe Baykal
Turkish Journal of Electrical Engineering and Computer Sciences
While the classical attack of ``monitor the network and intercept the password'' can be avoided by advanced protocols like SSH, one-time passwords are still considered a viable alternative or a supplement for software authentication since they are the only ones that safeguard against attacks on insecure client machines. In this paper by using public-key techniques we present a method called signature chain alternative to Lamport's hash chain to improve security and flexibility of one-time passwords. Our proposition improves the security because first, like other public-key authentication protocols, the server and the user do not share a secret, thereby eliminating attacks …
An Analytical Model For Calculating Bounds On Call Blocking Probabilities In Leo Satellite Networks, A. Hali̇m Zai̇m
An Analytical Model For Calculating Bounds On Call Blocking Probabilities In Leo Satellite Networks, A. Hali̇m Zai̇m
Turkish Journal of Electrical Engineering and Computer Sciences
We present an analytical model for calculating upper and lower bounds for call-blocking probabilities in a LEO satellite network that carries voice calls. The method is especially useful for large systems where calculation of call-blocking probabilities are too expensive. Our method calculates upper and lower bounds very easily and produces fairly accurate results.
Resonant Demagnetization Pwm Forward Converter, B. Bi̇lgi̇n, Işik Çadirci, R. Ergül, M. Ermi̇ş
Resonant Demagnetization Pwm Forward Converter, B. Bi̇lgi̇n, Işik Çadirci, R. Ergül, M. Ermi̇ş
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new approach to demagnetization process of a PWM forward converter (FC) is proposed. According to this approach, the demagnetization winding and diode of a conventional FC are removed, and an external capacitor is added in parallel with the secondary diode. This replacement changes the linear demagnetization process of a conventional FC into a resonant demagnetization process. The theoretical performance results of the proposed resonant demagnetization forward converter (RDFC) are compared with those of a conventional FC. A side by side comparison made between the two types of demagnetization strategies has shown that RDFC has some advantages …
Zero-Crossing Based Demodulation Of Minimum Shift Keying, Mi̇ne Kalkan, Feza Keresteci̇oğlu
Zero-Crossing Based Demodulation Of Minimum Shift Keying, Mi̇ne Kalkan, Feza Keresteci̇oğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Minimum shift keying (MSK) modulation has features such as constant envelope, compact spectrum and good error performance, which are all desirable in many digital applications including mobile radio. Numerous receiver structures to demodulate MSK have been suggested, such as correlation receivers, differential detectors and frequency discriminators. MSK is a form of biphase keying and can be detected by a zero-crossing based phase demodulator which gives near optimum performance. In this paper, the bit error performance of a zero-crossing based coherent MSK demodulator is theoretically investigated and a closed-form expression for the bit error rate is derived. The results indicate that …
Design Of A Tem-Cell With Increased Usable Test Area, Kresimir Malaric, Juraj Bartolic
Design Of A Tem-Cell With Increased Usable Test Area, Kresimir Malaric, Juraj Bartolic
Turkish Journal of Electrical Engineering and Computer Sciences
Transversal electromagnetic mode cells (TEM-cells) are used for electromagnetic compatibility measurements (emission and immunity), and for biomedical applications. Over the years, higher and higher frequencies are being used, which demands smaller transmission structures in order to obtain the homogeneous field distribution due to resonance. Such resonance destroys the TEM field, introducing higher order modes. The goal was to design the TEM-cell for GSM frequencies that will have a larger area with a homogeneous field used for testing, while still obtaining the characteristic impedance. Commercial TEM-cells used for frequencies of 900 MHz have only 2 cm in height available for testing, …
A Digitally Controlled Drive System For Travelling-Wave Ultrasonic Motor, Güngör Bal
A Digitally Controlled Drive System For Travelling-Wave Ultrasonic Motor, Güngör Bal
Turkish Journal of Electrical Engineering and Computer Sciences
A digitally controlled drive system was implemented in this study to control the speed and direction of a travelling-wave ultrasonic motor. The drive system, based on a 2-phase voltage-fed high-frequency serial-resonant inverter, uses the mechanical resonant frequency of an ultrasonic motor. A TMS320F243 digital signal processor was used to control an ultrasonic motor drive system. The speed control of the ultrasonic motor was achieved with a driving frequency in the 41.3-43.3 kHz frequency range. The feasible evaluations of the proposed drive and control system were tested by experiments. Experimental results demonstrated that the proposed drive and control system is flexible …
Parametrically Tunable Audio Shelving And Equalizing Ladder Wave Digital Filters, S. A. Samad
Parametrically Tunable Audio Shelving And Equalizing Ladder Wave Digital Filters, S. A. Samad
Turkish Journal of Electrical Engineering and Computer Sciences
Parametrically tunable audio equalizers are conventionally realized using allpass digital filter networks. They consist of first-order shelving filters and second-order equalizing filters. In this paper, ladder wave digital filters (WDFs) with parametrically tunable coefficients are proposed as shelving and equalizing filters. Similar to the allpass realization, the transfer function power complementary property of WDFs is used to obtain efficient shelving and equalizing filters. However, unlike the allpass structures, the transfer function and the tunable parameters of the ladder WDF are derived from the analog filter equivalent of the digital shelving and equalizing filters. For the shelving WDF, the cut-off frequency …
A New Simulator For Hvdc/Ac Systems-Part I, Baktiar Zangeneh, Abbas Shoulaie
A New Simulator For Hvdc/Ac Systems-Part I, Baktiar Zangeneh, Abbas Shoulaie
Turkish Journal of Electrical Engineering and Computer Sciences
A simulator with optimal step time (SOST) has been designed to investigate Large HVdc/ac systems. The adequacy and robustness of the simulator will be demonstrated by showing some important applications relevant to operation, operational planning and medium-term planing. Some of the features of our SOST simulator are optimal step time algorithm, interpolation, chatter removal, MATLAB interface, unlimited size of ac system, and Farsi command that help model complex power electronic circuits, provide fast and accurate results. On account of its reduced calculation effort and deterministic execution time, optimal-step simulation is a prerequisite for real-time performance. However, when simulating electromagnetic-transients behavior, …