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Articles 2911 - 2940 of 3096

Full-Text Articles in Physical Sciences and Mathematics

Modelling A Deposition Process In Collective Construction, Robert L. Stewart, R. Andrew Russell, Lindsay Kleeman Jan 2007

Modelling A Deposition Process In Collective Construction, Robert L. Stewart, R. Andrew Russell, Lindsay Kleeman

Turkish Journal of Electrical Engineering and Computer Sciences

During collective construction tasks, swarm robots coordinate their actions in space and time to build structures that conform to some given design or specification. In this paper, a simulation model and a mathematical model (based on a Markov chain) are introduced to describe the deposition process of a previously detailed robotic swarm system that uses templates and feedback to facilitate construction. The models are based on the behaviour and geometry of real robots and predict the dynamics observed during practical trials as well as explaining the occurrence of different spatial patterns of building blocks. Furthermore, the models provide an insight …


Swarm Robot Systems Based On The Evolution Of Personality Traits, Sidney Nascimento Givigi Jr. Jan 2007

Swarm Robot Systems Based On The Evolution Of Personality Traits, Sidney Nascimento Givigi Jr.

Turkish Journal of Electrical Engineering and Computer Sciences

Game theory may be very useful in modeling and analyzing swarms of robots. Using game theory in conjunction with traits of personalities, we achieve intelligent swarm robots. Traits of personality are characteristics of each robot that define the robots' behaviours. The environment is represented as a game and due to the evolution of the traits through a learning process, we show how the robots may react intelligently to changes in the environment. A proof of convergence for the proposed algorithm is offered. The process of selection of traits is discussed and the potential of the modeling is demonstrated in several …


New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska Jan 2007

New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska

Turkish Journal of Electrical Engineering and Computer Sciences

Precise calculation of parameters of thermoelectric modules and thermoelectric devices under operating conditions by present methods is very difficult. In this study, a new method is developed to calculate all parameters of thermoelectric modules. This new method makes it possible to determine the dynamic parameters of a real thermoelectric module operated under different working regimes. Measurement of thermoemf created by an operating module is the basis of this new method. An unloaded thermoelectric module, whose dynamic output parameters are necessary in the design of a medical helmet for the cooling of brain, has been investigated using this new method. A …


A Review Of Studies In Swarm Robotics, Levent Bayindir, Erol Şahi̇n Jan 2007

A Review Of Studies In Swarm Robotics, Levent Bayindir, Erol Şahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Swarm robotics is a new approach to the coordination of large numbers of relatively simple robots. The approach takes its inspiration from the system-level functioning of social insects which demonstrate three desired characteristics for multi-robot systems: robustness, flexibility and scalability. In this paper we have presented a preliminary taxonomy for swarm robotics and classified existing studies into this taxonomy after investigating the existing surveys related to swarm robotics literature. Our parent taxonomic units are modeling, behavior design, communication, analytical studies and problems. We are classifying existing studies into these main axes. Since existing reviews do not have enough number of …


A Sensitive Ann Based Differential Relay For Transformer Protection With Security Against Ct Saturation And Tap Changer Operation, Hassan Khorashadi Zadeh, Zuyi Li Jan 2007

A Sensitive Ann Based Differential Relay For Transformer Protection With Security Against Ct Saturation And Tap Changer Operation, Hassan Khorashadi Zadeh, Zuyi Li

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an artificial neural network (ANN) based scheme for fault identification in power transformer protection. The proposed scheme is featured by the application of ANN to identifying system patterns, the unique choice of harmonics of positive sequence differential currents as ANN inputs, the effective handling of current transformer (CT) saturation with an ANN based approach, and the consideration of tap changer position for correcting secondary CT current. Performance of the proposed scheme is studied for a wide variety of operating conditions using data generated from simulation. The results indicate that the proposed scheme provides a fast and sensitive …


A Communication Module And Tdma Scheduling For A Swarm Of Small Submarines, Ram Somaraju, Felix Schill Jan 2007

A Communication Module And Tdma Scheduling For A Swarm Of Small Submarines, Ram Somaraju, Felix Schill

Turkish Journal of Electrical Engineering and Computer Sciences

Swarming algorithms usually require fast and reliable local information distribution among neighbouring nodes. Additionally, many applications also require global information distribution in the shortest possible time. We show that communication links with a range which is small compared to the size of the swarm offer many advantages. We propose a system using low frequency radio communication as a viable alternative to acoustic communication. A time division multiple access algorithm is presented together with results from simulations. The presented system can be effectively used in large scale swarms of small submersibles.


Aggregation In Swarm Robotic Systems: Evolution And Probabilistic Control, Onur Soysal, Erki̇n Bahçeci̇, Erol Şahi̇n Jan 2007

Aggregation In Swarm Robotic Systems: Evolution And Probabilistic Control, Onur Soysal, Erki̇n Bahçeci̇, Erol Şahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In this study we investigate two approachees for aggregation behavior in swarm robotics systems: Evolutionary methods and probabilistic control. In first part, aggregation behavior is chosen as a case, where performance and scalability of aggregation behaviors of perceptron controllers that are evolved for a simulated swarm robotic system are systematically studied with different parameter settings. Using a cluster of computers to run simulations in parallel, four experiments are conducted varying some of the parameters. Rules of thumb are derived, which can be of guidance to the use of evolutionary methods to generate other swarm robotic behaviors as well. In the …


A Vrp-Based Route Planning For A Mobile Robot Group, Osman Parlaktuna, Aydin Si̇pahi̇oğlu, Ahmet Yazici Jan 2007

A Vrp-Based Route Planning For A Mobile Robot Group, Osman Parlaktuna, Aydin Si̇pahi̇oğlu, Ahmet Yazici

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a vehicle routing problem-based approach is presented to construct non-intersecting routes for the members of a mobile robot team. It is assumed that each robot starts from a central location such as the charging point, completes its route and returns to the starting location. The proposed method consists of three algorithms: a sweep algorithm determines the position of each node in clockwise (or counter clockwise) manner with respect to the starting location; savings algorithm calculates the saving obtained by adding a node to the route of a robot; Dijkstra's shortest path algorithm is used to calculate the …


Aggregation, Foraging, And Formation Control Of Swarms With Non-Holonomic Agents Using Potential Functions And Sliding Mode Techniques, Veysel Gazi̇, Bariş Fi̇dan, Y. Si̇nan Hanay, İlter Köksal Jan 2007

Aggregation, Foraging, And Formation Control Of Swarms With Non-Holonomic Agents Using Potential Functions And Sliding Mode Techniques, Veysel Gazi̇, Bariş Fi̇dan, Y. Si̇nan Hanay, İlter Köksal

Turkish Journal of Electrical Engineering and Computer Sciences

In this article we consider the aggregation, foraging, and formation control of swarms whose agents are moving in 2-dimensions with non-holonomic unicycle agent dynamics. We approach these problems using artificial potentials and sliding mode control. The main contribution is extension of the recent results (mainly for aggregation) in the literature based on a similar approach for simple integrator agent dynamics models to a significantly more realistic and more difficult setting with non-holonomic unicycle agent dynamics models. In particular, we design continuous-time control schemes via a constructive analysis based on artificial potential functions and sliding mode control techniques. The effectiveness of …


Study Of The Warranty Cost Model For Software Reliability With An Imperfect Debugging Phenomenon, D.R. Prince Williams Jan 2007

Study Of The Warranty Cost Model For Software Reliability With An Imperfect Debugging Phenomenon, D.R. Prince Williams

Turkish Journal of Electrical Engineering and Computer Sciences

Software reliability is one of the most important characteristics of software quality. Its measurement and management technologies employed during the software life-cycle are essential for producing and maintaining quality/reliable software systems. Herein, we discuss a modified approach to calculating the delivery cost of a software product, when warranty is to be provided, with an imperfect debugging phenomenon. Unlike existing cost models, here the strategy was to consider maintenance support given to the customer with an imperfect debugging phenomenon. The optimal release time can be calculated for various reliability levels by minimizing the cost. The delivery cost, reliability of the software …


Using Angle Of Arrival (Bearing) Information For Localization In Robot Networks, Tolga Eren Jan 2007

Using Angle Of Arrival (Bearing) Information For Localization In Robot Networks, Tolga Eren

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we consider using angle of arrival information (bearing) for localization in robot networks. The essential property we require in this paper is that a node can infer heading information from its neighbors. We address the uniqueness of network localization solutions by the theory of globally rigid graphs. We show that while the parallel rigidity problem for formations with bearings is isomorphic to the distance case, the global rigidity of the formation is simpler (in fact identical to the simpler rigidity case) for a network with bearings, compared to formations with distances. We provide the conditions of localization …


Swarms In Biology And Engineering, Kevin M. Passino Jan 2007

Swarms In Biology And Engineering, Kevin M. Passino

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Design And Implementation Of An Ad-Hoc Routing Protocol For Mobile Robots, Carlos Agüero, Jose M. Canas, Miguel Ortu˜No, Vicente Matellan Jan 2007

Design And Implementation Of An Ad-Hoc Routing Protocol For Mobile Robots, Carlos Agüero, Jose M. Canas, Miguel Ortu˜No, Vicente Matellan

Turkish Journal of Electrical Engineering and Computer Sciences

Mobile robots need to be able to communicate among themselves, as well as with hosts participating in the task that they are all involved in. Wired networks are obviously not suitable for mobile robots. Current wireless networks based on a fixed infrastructure (GSM, WiFi, etc.) to route packets may not be suitable because this infrastructure does not cover every place and the requirements of its resources. The best choice for mobile robots are Ad-Hoc networks, which are wireless and do not need a fixed infrastructure. This article describes PERA, a complete communications library including link, net, and transport layers for …


Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba Jan 2007

Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a simple and effective signature verification method that depends only on the raw binary pixel intensities and avoids using complex sets of features. The method looks at the signature verification problem as a graph matching problem. The method is tested using genuine and forgery signatures produced by five subjects. An equal error rate of 26.7% and 5.6% was achieved for skilled and random forgeries, respectively. A positive property of our algorithm is that the false acceptance rate of random forgeries vanishes at the point of equal false rejection and skilled forgery false acceptance rates. Keeping …


Umts-Hsdpa In High Altitude Platforms (Haps) Communications, Bazil Taha Ahmed, Miguel Calvo Ramon, Leandro De Haro-Ariet Jan 2007

Umts-Hsdpa In High Altitude Platforms (Haps) Communications, Bazil Taha Ahmed, Miguel Calvo Ramon, Leandro De Haro-Ariet

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the performance of HAPs (High Altitudes Platforms) UMTS HSDPA (High Speed Downlink Packet Access) is studied for different HAPs height h, different cells radius R and two directions (0° and 30°) within the cell. The network under study is assumed to have 61 ground cells. It is noticed that, for urban zone users, the effective range is lower than the effective range for users in rural zones for a given modulation scheme. Also it is noticed that in rural zone, the HSDPA can support higher modulation schemes. It is noticed that, when 80% of the base station …


Optimal Location For Shunt Connected Facts Devices In A Series Compensated Long Transmission Line, P.R. Sharma, Ashok Kumar, Narender Kumar Jan 2007

Optimal Location For Shunt Connected Facts Devices In A Series Compensated Long Transmission Line, P.R. Sharma, Ashok Kumar, Narender Kumar

Turkish Journal of Electrical Engineering and Computer Sciences

Shunt FACTS devices are used for controlling transmission voltage, power flow, reducing reactive losses, and damping of power system oscillations for high power transfer levels. In this paper the optimal location of a shunt FACT device is investigated for an actual line model of a transmission line having series compensation at the center. Effect of change in degree of series compensation on the optimal location of the shunt FACTS device to get the highest possible benefit is studied. It is found that the optimal location of the shunt FACTS device varies with the change in the level of series compensation …


A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇ Jan 2007

A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Seismo-electromagnetic precursory-based earthquake prediction studies are criticized in terms of their scientific content, problem complexity, signal excitation and propagation, causal relations with earthquakes, and public awareness and expectations. One aim is to trigger a new debate on this hot topic in the Electromagnetic Society.


A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou Jan 2007

A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an original variable gain PI (VGPI) controller for speed control of a direct torque neuro fuzzy controlled (DTNFC) induction motor drive. First, a VGPI speed controller is designed to replace the classical PI controller in a conventional direct torque controlled induction motor drive. Its simulated performances are then compared to those of a classical PI controller. Then, a direct torque neuro fuzzy control (DTNFC) for a voltage source PWM inverter fed induction motor drive is presented. This control scheme uses the stator flux amplitude and the electromagnetic torque errors through an adaptive NF inference system (ANFIS) to …


Data Mining And Costas Arrays, Konstantinos Drakakis Jan 2007

Data Mining And Costas Arrays, Konstantinos Drakakis

Turkish Journal of Electrical Engineering and Computer Sciences

Costas arrays are used in RADAR (and SONAR) engineering to represent frequency-hopping patterns that optimize the RADAR's performance. In this work, using all available Costas arrays up to and including order 26, as well as data mining techniques, we investigate how the Costas property and the balance of signs in the difference triangle of a permutation are related. Our conclusion is that there is sufficient evidence to believe that the mechanism responsible for the formation of Costas arrays changes from low to high orders.


Controlling Rail Potential Of Dc Supplied Rail Traction Systems, Mehmet Turan Söylemez, Süleyman Açikbaş, Adnan Kaypmaz Jan 2006

Controlling Rail Potential Of Dc Supplied Rail Traction Systems, Mehmet Turan Söylemez, Süleyman Açikbaş, Adnan Kaypmaz

Turkish Journal of Electrical Engineering and Computer Sciences

Most modern DC electrified mass transit systems use a totally floating earth as their grounding strategy. A well-known problem related with totally floating systems is that the touch potentials can be dangerously high. In order to reduce the voltages on rails, several devices exist. Most of these devices allow a direct connection to earth when a certain voltage threshold is exceeded. In this paper, the working principles of these devices are given and the effect of certain parameters related with these devices on the minimum achievable touch potentials is investigated.


An Experience On Problem Based Learning In An Engineering Faculty, Cüneyt Güzeli̇ş Jan 2006

An Experience On Problem Based Learning In An Engineering Faculty, Cüneyt Güzeli̇ş

Turkish Journal of Electrical Engineering and Computer Sciences

In 2001, Engineering Faculty of Dokuz Eylül University has started to change its undergraduate education in a radical way. As being among the first examples in the world, the Departments of Electrical and Electronics, Geological and Geophysics Engineering in 2002 and Mining Engineering Department in 2003 have adopted the so-called "modular-staged problem based active learning system". The system is based on real engineering problems which values teamwork and the integration of information from different disciplines and it places the student at the center of the learning process. The faculty has learned many things and it needs to learn many other …


An International Dialogue On Electrical Engineering Education, Thales Papazoglou Jan 2006

An International Dialogue On Electrical Engineering Education, Thales Papazoglou

Turkish Journal of Electrical Engineering and Computer Sciences

. PAPAZOGLOU Chairman -- ELCOMPEET'04 Technological Educational Institute of Crete, GREECE e-mail: [email protected]


Computational Sciences: At The Intersection Of Science And Engineering--Case Study For Academic And Research Programs, Menas Kafatos, Peter Becker, Zafer Boybeyi̇ Jan 2006

Computational Sciences: At The Intersection Of Science And Engineering--Case Study For Academic And Research Programs, Menas Kafatos, Peter Becker, Zafer Boybeyi̇

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Modeling And Simulation Concepts In Engineering Education: Virtual Tools, Levent Sevgi̇ Jan 2006

Modeling And Simulation Concepts In Engineering Education: Virtual Tools, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

This article reviews fundamental concepts of modeling and simulation in computational sciences, such as a model, analytical- and numerical-based modeling, simulation, validation, verification, etc., in relation to the virtual labs widely-offered as parts of engineering education. Virtual tools that can be used in electromagnetic engineering are also introduced.


Readjusting The Current Trend In Electrical Power Engineering, Johan Smit, Peter Morshuis, Edward Gulski Jan 2006

Readjusting The Current Trend In Electrical Power Engineering, Johan Smit, Peter Morshuis, Edward Gulski

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper the electrical power education curriculum is analyzed from the viewpoint of the electrical power industry and from the viewpoint of young people that contemplate their future academic study. From the perspective of young people in industrialized countries contemplating their future and the possibilities of an academic study, the current curriculum in (power) engineering lacks attraction. The number of freshmen still shows a decreasing trend. This paper is aimed to be a contribution towards readjusting this trend


Online Learning Resource For Smooth Transition From High School To Engineering Education, Riadh W. Y. Habash, Christine Suurtaam, Mustapha C. E. Yagoub, Karima Kara, Ghanim Ibrahim Jan 2006

Online Learning Resource For Smooth Transition From High School To Engineering Education, Riadh W. Y. Habash, Christine Suurtaam, Mustapha C. E. Yagoub, Karima Kara, Ghanim Ibrahim

Turkish Journal of Electrical Engineering and Computer Sciences

Although high school mathematics curriculum documents in Ontario, Canada have, for the past two decades, made calls for classroom practices involving both modeling and applications, students still experience difficulties in moving into a university engineering program. This paper discusses a new initiative in online learning and the teaching of mathematical modeling and applications in engineering education at the University of Ottawa, Canada. In particular, we explore how modeling and Internet technologies can enhance progress in engineering education.


A Labview-Based Virtual Instrument For Engineering Education: A Numerical Fourier Transform Tool, Levent Sevgi̇, Çağatay Uluişik Jan 2006

A Labview-Based Virtual Instrument For Engineering Education: A Numerical Fourier Transform Tool, Levent Sevgi̇, Çağatay Uluişik

Turkish Journal of Electrical Engineering and Computer Sciences

Engineering is based on practice. The minima of this practice should be given during the university education. This has become more and more comprehensive and expensive parallel to high-technology devices developed and presented to societies. Computers, microprocessor-based devices, programmable systems on Chip (PSoC), etc., make engineering education not only very complex but interdisciplinary as well. Building undergraduate labs has become more and more expensive if only physical experimentation and hands-on training are targeted. On the other hand, simple, comparatively much cheaper software may turn a regular personal computer (PC) into a virtual lab. The key question therefore is, to establish …


Complex Analysis Of The Lossy-Transmission Line Theory: A Generalized Smith Chart, E. Gago-Ribas, C. Dehesa-Martinez, M. J. Gonzalez-Morales Jan 2006

Complex Analysis Of The Lossy-Transmission Line Theory: A Generalized Smith Chart, E. Gago-Ribas, C. Dehesa-Martinez, M. J. Gonzalez-Morales

Turkish Journal of Electrical Engineering and Computer Sciences

It has been very usual in the specialized literature to skip the detailed study of the lossy transmission line theory by reducing it to the low-loss approximation. Although this is valid in the most common practical cases, the study of the general lossy case becomes very important due to the fact that it makes possible a better and deeper understanding of the physical effects associated to general losses, as well as the low-loss frequency-dependent regime. Besides, the analysis of the general case provides important results that may be extended to the analysis of real waveguiding systems, facilitating the understanding and …


An Adaptive Feedforward Amplifier Application For 5.8 Ghz, Engi̇n Kurt, Osman Palamutçuoğullari Jan 2006

An Adaptive Feedforward Amplifier Application For 5.8 Ghz, Engi̇n Kurt, Osman Palamutçuoğullari

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a 5.8 GHz power amplifier is linearized by an adaptive feedforward technique. A DSP-based control scheme is applied to reduce the intermodulation distortion of this amplifier. A two-tone test is used to verify the design.


Artificial Neural Design Of Microstrip Antennas, Nurhan Türker, Fi̇li̇z Güneş, Tülay Yildirim Jan 2006

Artificial Neural Design Of Microstrip Antennas, Nurhan Türker, Fi̇li̇z Güneş, Tülay Yildirim

Turkish Journal of Electrical Engineering and Computer Sciences

A general design procedure is suggested for microstrip antennas using artificial neural networks and this is demonstrated using rectangular patch geometry. In this design procedure, synthesis is defined as the forward side and then analysis as the reverse side of the problem. Worked examples are given using the most efficient materials.