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Full-Text Articles in Physical Sciences and Mathematics

Artificial Bee Colony Algorithm For Dynamic Deployment Of Wireless Sensor Networks, Celal Öztürk, Dervi̇ş Karaboğa, Beyza Görkemli̇ Jan 2012

Artificial Bee Colony Algorithm For Dynamic Deployment Of Wireless Sensor Networks, Celal Öztürk, Dervi̇ş Karaboğa, Beyza Görkemli̇

Turkish Journal of Electrical Engineering and Computer Sciences

As the usage and development of wireless sensor networks increases, problems related to these networks are being discovered. Dynamic deployment is one of the main issues that directly affect the performance of wireless sensor networks. In this paper, an artificial bee colony algorithm is applied to the dynamic deployment of mobile sensor networks to gain better performance by trying to increase the coverage area of the network. The good performance of the algorithm shows that it can be utilized in the dynamic deployment of wireless sensor networks.


Reduction Of Torque Ripple In Dtc For Induction Motor Using Input-Output Feedback Linearization, Sebti Belkacem, Farid Naceri, Rachid Abdessemed Jan 2012

Reduction Of Torque Ripple In Dtc For Induction Motor Using Input-Output Feedback Linearization, Sebti Belkacem, Farid Naceri, Rachid Abdessemed

Turkish Journal of Electrical Engineering and Computer Sciences

Direct torque control (DTC) is known to produce fast responses and robust control in AC adjustable-speed drives. However, in the steady-state operation, notable torque, flux, and current pulsations occur. In this paper, nonlinear DTC of induction motor drives is presented based on a space vector pulse-width modulation scheme combined with the input-output feedback linearization technique. The variation of stator and rotor resistance due to changes in temperature or frequency deteriorates the performance of the DTC controller by introducing errors in the estimated flux linkage and the electromagnetic torque. This approach will not be suitable for high power drives such as …


Performance Comparison Of New Nonparametric Independent Component Analysis Algorithm For Different Entropic Indexes, Yusuf Sevi̇m, Ayten Atasoy Jan 2012

Performance Comparison Of New Nonparametric Independent Component Analysis Algorithm For Different Entropic Indexes, Yusuf Sevi̇m, Ayten Atasoy

Turkish Journal of Electrical Engineering and Computer Sciences

Most independent component analysis (ICA) algorithms use mutual information (MI) measures based on Shannon entropy as a cost function, but Shannon entropy is not the only measure in the literature. In this paper, instead of Shannon entropy, Tsallis entropy is used and a novel ICA algorithm, which uses kernel density estimation (KDE) for estimation of source distributions, is proposed. KDE is directly evaluated from the original data samples, so it solves the important problem in ICA: how to choose nonlinear functions as the probability density function (pdf) estimation of the sources.


A Simulator Based On An Energy-Efficient Gpr Algorithm Modified For The Scanning Of All Types Of Regions, Levent Seyfi̇, Ercan Yaldiz Jan 2012

A Simulator Based On An Energy-Efficient Gpr Algorithm Modified For The Scanning Of All Types Of Regions, Levent Seyfi̇, Ercan Yaldiz

Turkish Journal of Electrical Engineering and Computer Sciences

An improved simulator is presented for the simulation of an energy-efficient ground-penetrating radar (GPR) using the 2D finite-difference time-domain method in the MATLAB environment. This simulator is novel in that it improves on previous work that did not involve scanning a buried object or the intermittent sublayer beneath the ground using an energy-efficient algorithm. The present simulator examines the scanned region and automatically chooses either a common algorithm or an energy-efficient algorithm, depending on the region. The simulator provides the possibility of using an energy-efficient GPR without the need for the operator to determine the suitability of the scanned region. …


Design, Implementation, And Performance Analysis Of The Worldfip/Atm Local Bridge, Tuncay Aydoğan, İbrahi̇m Özçeli̇k, Aki̇f Kutlu, Hüseyi̇n Eki̇z Jan 2012

Design, Implementation, And Performance Analysis Of The Worldfip/Atm Local Bridge, Tuncay Aydoğan, İbrahi̇m Özçeli̇k, Aki̇f Kutlu, Hüseyi̇n Eki̇z

Turkish Journal of Electrical Engineering and Computer Sciences

World factory instrumentation protocol (WorldFIP) is a fieldbus network protocol that provides a link between level zero (sensors/actuators) and level one (field controllers such as programmable logic controllers, etc.) in industrial automation systems. Accessing and connecting the WorldFIP remotely is important for monitoring, maintaining, and controlling devices in a factory in which asynchronous transfer mode (ATM) is used as a backbone network. In this study, a transparent WorldFIP/ATM bridge was designed and implemented in order to access devices on WorldFIP via an ATM network. This designed bridge may also provide control of the devices over wide area networks. The bridge's …


Effects Of Routing Algorithms On Novel Throughput Improvement Of Mobile Ad Hoc Networks, Barbaros Preveze, Aysel Şafak Jan 2012

Effects Of Routing Algorithms On Novel Throughput Improvement Of Mobile Ad Hoc Networks, Barbaros Preveze, Aysel Şafak

Turkish Journal of Electrical Engineering and Computer Sciences

A cognitive method called most congested access first (MCAF), minimizing the packet loss ratio and improving the throughput of a multihop mobile WiMAX network, is proposed. MCAF combines both the time division multiple access and the orthogonal frequency division multiple access methods. MCAF additionally uses spectral aid and buffer management methods, which are proposed in this paper, to manage both spectrum access and packets in the buffers. By using these novel methods, real-time video and voice packet transmission is achieved, data packet loss rate is minimized, and the system throughput per node is improved. Effects of fastest path and ant …


Simulated Annealing Algorithm-Based Elman Network For Dynamic System Identification, Adem Kalinli Jan 2012

Simulated Annealing Algorithm-Based Elman Network For Dynamic System Identification, Adem Kalinli

Turkish Journal of Electrical Engineering and Computer Sciences

One of the well-known recurrent neural networks is the Elman network. Recently, it has been used in applications of system identification. The network has feedforward and feedback connections. It can be trained essentially as a feedforward network by means of the basic backpropagation algorithm, but its feedback connections have to be kept constant. For training success, it is important to select the correct values for the feedback connections. However, finding these values manually can be a lengthy trial-and-error process. This paper investigates the use of the simulated annealing (SA) algorithm to obtain the weight values of both the feedforward and …


A New Formulation Method For Solving Kinematic Problems Of Multiarm Robot Systems Using Quaternion Algebra In The Screw Theory Framework, Emre Sariyildiz, Hakan Temeltaş Jan 2012

A New Formulation Method For Solving Kinematic Problems Of Multiarm Robot Systems Using Quaternion Algebra In The Screw Theory Framework, Emre Sariyildiz, Hakan Temeltaş

Turkish Journal of Electrical Engineering and Computer Sciences

We present a new formulation method to solve the kinematic problem of multiarm robot systems. Our major aims were to formulize the kinematic problem in a compact closed form and avoid singularity problems in the inverse kinematic solution. The new formulation method is based on screw theory and quaternion algebra. Screw theory is an effective way to establish a global description of a rigid body and avoids singularities due to the use of the local coordinates. The dual quaternion, the most compact and efficient dual operator to express screw displacement, was used as a screw motion operator to obtain the …


Noncausal Forward/Backward Two-Pass Iir Digital Filters In Real Time, Adnane Mouffak, Belbachir Mohamed Faouzi Jan 2012

Noncausal Forward/Backward Two-Pass Iir Digital Filters In Real Time, Adnane Mouffak, Belbachir Mohamed Faouzi

Turkish Journal of Electrical Engineering and Computer Sciences

A novel method for implementing noncausal forward/backward 2-pass recursive digital filters in real time is presented. It is based on a segment-wise block processing scheme without overlapping. Factors that degrade the linearity of the overall system's transfer function are discussed. An analytical condition that corrects the system's linearity is elaborated upon using the state variable approach. A recursive algorithm is developed to compute an implementable condition for real-time filtering. A single first in, first out queue memory is introduced to ensure an organized and continuous data stream into the proposed system. This technique allows real-time, sample-by-sample filtering, and it yields …


A Hybrid Approach For Power Quality Monitoring, Okan Özgönenel, Ümi̇t Kemaletti̇n Terzi̇, Abdesh Khan Jan 2012

A Hybrid Approach For Power Quality Monitoring, Okan Özgönenel, Ümi̇t Kemaletti̇n Terzi̇, Abdesh Khan

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel hybrid approach for detection of power quality (PQ) disturbances. The proposed hybrid algorithm is based on applications of principle component analysis, discrete wavelet transform, and fast Fourier transform on voltage and current waveforms. The proposed PQ monitoring (PQM) software uses 3-phase voltage and current signals in order to detect possible power disturbances such as voltage sag, flicker, harmonics, transients, DC component, and electromagnetic interference. The test results demonstrate the potential of the proposed hybrid technique for PQM andPQ assessment.


Vibration Analysis Of Base Structure On Sins Using Pzt Actuators, Bin Zheng, Jianfeng Yang Jan 2012

Vibration Analysis Of Base Structure On Sins Using Pzt Actuators, Bin Zheng, Jianfeng Yang

Turkish Journal of Electrical Engineering and Computer Sciences

A steel plate bonded with lead zirconate titanate (PZT) actuators was studied on the basis of finite element methods (FEMs). The damping amplitudes of this plate bonded with PZT actuators were obtained at different locations and under different control conditions by analyzing the distribution of the PZT plate's strain tensor in the first 4 modes. Furthermore, to reduce the unwanted disturbance and mitigate the errors from sensors, a base structure of the missile's strapdown inertial navigation system (SINS) is also proposed. The results show that the vibration control can be enhanced by increasing the number of the PZT actuators bonded. …


Skewed Alpha-Stable Distributions For Modeling And Classification Of Musical Instruments, Mehmet Erdal Özbek, Mehmet Emre Çek, Feri̇t Acar Savaci Jan 2012

Skewed Alpha-Stable Distributions For Modeling And Classification Of Musical Instruments, Mehmet Erdal Özbek, Mehmet Emre Çek, Feri̇t Acar Savaci

Turkish Journal of Electrical Engineering and Computer Sciences

Music information retrieval and particularly musical instrument classification has become a very popular research area for the last few decades. Although in the literature many feature sets have been proposed to represent the musical instrument sounds, there is still need to find a superior feature set to achieve better classification performance. In this paper, we propose to use the parameters of skewed alpha-stable distribution of sub-band wavelet coefficients of musical sounds as features and show the effectiveness of this new feature set for musical instrument classification. We compare the classification performance with the features constructed from the parameters of generalized …


A Pseudo Spot Price Of Electricity Algorithm Applied To Environmental Economic Active Power Dispatch Problem, Celal Yaşar Jan 2012

A Pseudo Spot Price Of Electricity Algorithm Applied To Environmental Economic Active Power Dispatch Problem, Celal Yaşar

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an environmental economic active power dispatch problem is transformed into an optimization problem with a single-objective function by applying the weighted sum method (WSM) and the conic scalarization method (CSM). A pseudo spot price of electricity algorithm (PSPA) is used to solve the transformed problem. This is demonstrated on an example problem, which is a lossy electrical power system having only thermal units The WSM and CSM methods are applied to the example problem, and the weight factor values of these methods is increased from 0 to 1 by a step size of 0.1. For each possible …


Optimal In Vitro Realization Of Pulsatile Coronary Artery Flow Waveforms Using Closed-Loop Feedback Algorithms With Multiple Flow Control Devices, Serdar Yilmaz, Onur Toker, Nurullah Arslan, Herman Sedef Jan 2012

Optimal In Vitro Realization Of Pulsatile Coronary Artery Flow Waveforms Using Closed-Loop Feedback Algorithms With Multiple Flow Control Devices, Serdar Yilmaz, Onur Toker, Nurullah Arslan, Herman Sedef

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we study optimal in vitro realization of pulsatile coronary artery flows using newly proposed closed-loop feedback algorithms with a clearly defined mathematical performance objective, and we compare several flow control device technologies in terms of their ability to generate pulsatile flow signals as accurately as possible. In the literature, there are several published results for in vitro pulsatile flow realization systems. However, most of the proposed systems operate in an open-loop setting and use a single flow control device, and their performance is assessed mostly by graphical means without a clearly defined mathematical performance objective. Furthermore, some …


A Novel Approach For Optimal Allocation Of Distributed Generations Based On Static Voltage Stability Margin, Mohsen Rezaie Estabragh, Mohsen Mohammadian, Mehdi Shafiee Jan 2012

A Novel Approach For Optimal Allocation Of Distributed Generations Based On Static Voltage Stability Margin, Mohsen Rezaie Estabragh, Mohsen Mohammadian, Mehdi Shafiee

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a newly developed approach to find the optimal location of distributed generations (DGs) to improve power system voltage stability margin and reduce losses incorporating the constraints. The loadability limit index is used to assess the static voltage stability security margin, which is associated with the point of voltage collapse limit. Based on this, a toolbox is developed to recognize the loadability margin in power networks. Finally, the mentioned problem is modeled as a nonlinear and multiobjective optimization problem. The proposed method establishes a tradeoff between the security index and power losses in DG placement using the hybrid …


A Novel Motor Speed Calculation Method Using Square Wave Speed Sensor Signals Via Fast Fourier Transform, Hayri̇ Arabaci, Osman Bi̇lgi̇n Jan 2012

A Novel Motor Speed Calculation Method Using Square Wave Speed Sensor Signals Via Fast Fourier Transform, Hayri̇ Arabaci, Osman Bi̇lgi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel motor speed measurement method and experimental results using the fast Fourier transform (FFT). Motor speed is obtained using the square wave output signal of a speed sensor. In the proposed method, the speed can be measured in a wide range, and transient speed changes can also be clearly observed. The experiments were conducted during start-up and in steady state. The sampled speed data were transformed to frequency spectrums using the FFT. The frequency, which corresponds to the maximum amplitude in the spectrum, was used to calculate the motor speed. The test results show that the …


Voltage Stability Via Energy Function Analysis On Reduced Order Model Of Power System, Ahmet Çi̇fci̇, Yilmaz Uyaroğlu, Mehmet Ali̇ Yalçin Jan 2012

Voltage Stability Via Energy Function Analysis On Reduced Order Model Of Power System, Ahmet Çi̇fci̇, Yilmaz Uyaroğlu, Mehmet Ali̇ Yalçin

Turkish Journal of Electrical Engineering and Computer Sciences

A power system is a typical nonlinear dynamical system and voltage stability is an important subject of power system stability. This paper describes the use of the variable gradient method in a reduced order model of a single-machine infinite-bus power system. Additionally, the system's Lyapunov (energy) function is created and thus the system's energy level changes' effects on the system's stability are shown using the MACSYMA program. The Lyapunov function allows the determination of stability for nonlinear systems without the need to find exact solutions.


Analysis And Characterization Of Longitudinal Flux Single-Sided Linear Switched Reluctance Machines, Lenin Chokkalingam, Arumugam Rengasamy Jan 2012

Analysis And Characterization Of Longitudinal Flux Single-Sided Linear Switched Reluctance Machines, Lenin Chokkalingam, Arumugam Rengasamy

Turkish Journal of Electrical Engineering and Computer Sciences

Linear switched reluctance motors (LSRMs) have recently gained more popularity for propulsion drives. This paper contributes a certain design improvement to reduce the force ripple in LSRMs. By affixing a pole cap in the stator pole, the target is achieved. Finite element analysis has been carried out to predict the performance of the basic and proposed structures. Motor performances for different load conditions are simulated. The application of fast Fourier transform has been utilized to envisage the vibration frequencies. The experimental results are well correlated with the predicted results.


Obtaining The Secondary Impedance Of Single-Sided Linear Induction Motor With A Double Layer Reaction Rail: A New Approach, Ali̇ Suat Gerçek, Vedat Mehmet Karsli Jan 2011

Obtaining The Secondary Impedance Of Single-Sided Linear Induction Motor With A Double Layer Reaction Rail: A New Approach, Ali̇ Suat Gerçek, Vedat Mehmet Karsli

Turkish Journal of Electrical Engineering and Computer Sciences

In the performance calculations of single-sided linear induction motor (SLIM),the equivalent circuit technique (ECT) is used. In this paper, a new approach is proposed for obtaining the secondary impedance of single-sided linear induction motor (SLIM) with a double layer reaction rail by using the layered secondary model. The proposed method improves the ECT technique by considering the saturation effect and the non-linear complex equivalent relative permeability. This study also examines the contributions of other electromagnetic effects, such as longitudinal end effect and transverse edge effect as well. Our method is applied to the SLIM and computed results of the method …


A Logic Method For Efficient Reduction Of The Space Complexity Of The Attribute Reduction Problem, Mehmet Hacibeyoğlu, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli Jan 2011

A Logic Method For Efficient Reduction Of The Space Complexity Of The Attribute Reduction Problem, Mehmet Hacibeyoğlu, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli

Turkish Journal of Electrical Engineering and Computer Sciences

The goal of attribute reduction is to find a minimal subset (MS) R of the condition attribute set C of a dataset such that R has the same classification power as C. It was proved that the number of MSs for a dataset with n attributes may be as large as (_{n/2}^n) and the generation of all of them is an NP-hard problem. The main reason for this is the intractable space complexity of the conversion of the discernibility function (DF) of a dataset to the disjunctive normal form (DNF). Our analysis of many DF-to-DNF conversion processes showed that approximately …


A Vision Based Feedback Mechanism For 6-Dof Stewart Platform, Utku Büyükşahi̇n Jan 2011

A Vision Based Feedback Mechanism For 6-Dof Stewart Platform, Utku Büyükşahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Eyes are the most ubiquitous sensors of humankind. However, ``Vision Based Sensors" are not as common as what this fact would suggest. A survey of the previous work on image processing would reveal that the bulk of the research in this area have been conducted since the year 2000. These facts clearly show that image processing is the technology of our century, and is very open to further development. In this work, a system that combines a classical mechanism of the 20th century with the recent technology of the 21st century is presented and the design, theoretical background, the software …


Experimental Analysis Of An Alternator Excited With Photovoltaic Cells For Small Power Plants, Kami̇l Ri̇fat İrfan Güney, Nevzat Onat Jan 2011

Experimental Analysis Of An Alternator Excited With Photovoltaic Cells For Small Power Plants, Kami̇l Ri̇fat İrfan Güney, Nevzat Onat

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an automatic voltage regulator fed by photovoltaic (PV) cells was designed for use in small power alternators. The design aimed to increase the energy output of the alternator and to ensure necessary current output from the PV cells to support the synchronous generator excitation system. For energy transformation from small renewable energy sources, designers have favored the use of alternators that produce higher quality electric power, rather than asynchronous generators. We also address the designed system's suitability for real-life application, examining the steady-state performance of the photovoltaic cell excited alternator (PVCEA) with various loads and its behavior …


Design And Evaluation Of A Query-Based Jamming Detection Algorithm For Wireless Sensor Networks, Murat Çakiroğlu, Ahmet Turan Özceri̇t Jan 2011

Design And Evaluation Of A Query-Based Jamming Detection Algorithm For Wireless Sensor Networks, Murat Çakiroğlu, Ahmet Turan Özceri̇t

Turkish Journal of Electrical Engineering and Computer Sciences

Jamming attacks, which are the main cause of data corruption and network blockages in wireless sensor networks (WSNs), are one of the most serious threats for WSNs. This type of attack not only blocks the ongoing communication in the network, but also causes the wireless nodes to exhaust their energy much earlier than expected. A countermeasure must be deployed against jamming attacks, especially in military and medical applications in which security breaches cannot be tolerated. In this paper, we have designed a new query-based jamming detection algorithm (QUJDA) to detect jamming attacks occurring in WSNs. QUJDA is an attack detection …


Line Detection With Adaptive Random Samples, Ali̇ Cafer Gürbüz Jan 2011

Line Detection With Adaptive Random Samples, Ali̇ Cafer Gürbüz

Turkish Journal of Electrical Engineering and Computer Sciences

This paper examines the detection of parameterized shapes in multidimensional noisy grayscale images. A novel shape detection algorithm utilizing random sample theory is presented. Although the method can be generalized, line detection is detailed. Each line in the image corresponds to a point in the line parameter space. The method creates hypothesis lines by randomly selecting parameter space points and tests the surrounding regions for acceptable linear features. The information obtained from each randomly selected line is used to update the parameter distribution, which reducesi the required number of random trials. The selected lines are re-estimated within a smaller search …


Automatic Knowledge Extraction For Filling In Biography Forms From Turkish Texts, İlknur Pehli̇van, Zeynep Orhan Jan 2011

Automatic Knowledge Extraction For Filling In Biography Forms From Turkish Texts, İlknur Pehli̇van, Zeynep Orhan

Turkish Journal of Electrical Engineering and Computer Sciences

This study presents a method for building an automatic knowledge extraction system for filling in biography forms from Turkish texts. Several biographies are analyzed in order to choose the set of biography categories to be studied. The fields of the biography form to be created are also defined based on this analysis. Information extraction techniques are used for implementation. A separate testing platform is designed to evaluate the accuracy of the extracted data. Results of the testing platform have shown this study to be a promising process to be further developed especially for creating forms in the Turkish language.


Neuro-Fuzzy Soft-Switching Hybrid Filter For Impulsive Noisy Environments, Şaban Özer, Hasan Zorlu Jan 2011

Neuro-Fuzzy Soft-Switching Hybrid Filter For Impulsive Noisy Environments, Şaban Özer, Hasan Zorlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a new soft-switching hybrid filter based on a neuro-fuzzy network for impulsive noisy environments is proposed. The hybrid filter was built by combining an adaptive finite impulse response (FIR) filter, an adaptive weighted myriad (WMy) filter, and a soft-switching mechanism based on a neuro-fuzzy (NF) network. Performance of the hybrid filter was tested in \alpha-stable noisy situations and compared with adaptive FIR, WMy, and weighted median (WMd) filter performances. According to the simulation results; the proposed hybrid filter has better performance than the adaptive FIR, WMy, and WMd filters, and has the ability of effectively suppressing the …


Simulation Of Storage Time Versus Reverse Bias Current For P^+N And Pin Diodes, Mehmet Serhat Keserli̇oğlu, Hasan Hüseyi̇n Erkaya Jan 2011

Simulation Of Storage Time Versus Reverse Bias Current For P^+N And Pin Diodes, Mehmet Serhat Keserli̇oğlu, Hasan Hüseyi̇n Erkaya

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the reverse-recovery behaviors of pin and p^+n diodes were simulated as a function of the reverse current and carrier lifetime. For this purpose, a 1-D simulation program was written to solve the semiconductor equations. MatLab partial differential equation solver was used. The reverse recovery response of pin and p^+n diodes was obtained for various values of a resistor in series and of carrier lifetime. The transient response for voltage and current was determined.


Co-Occurrence Matrix And Its Statistical Features As A New Approach For Face Recognition, Alaa Eleyan, Hasan Demirel Jan 2011

Co-Occurrence Matrix And Its Statistical Features As A New Approach For Face Recognition, Alaa Eleyan, Hasan Demirel

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new face recognition technique is introduced based on the gray-level co-occurrence matrix (GLCM). GLCM represents the distributions of the intensities and the information about relative positions of neighboring pixels of an image. We proposed two methods to extract feature vectors using GLCM for face classification. The first method extracts the well-known Haralick features from the GLCM, and the second method directly uses GLCM by converting the matrix into a vector that can be used in the classification process. The results demonstrate that the second method, which uses GLCM directly, is superior to the first method that …


Analysis Of Frequency Characteristics Of Electrical Arcs On The Insulating Sheath Of The Adss Fiber Optic Cables, Cengi̇z Polat Uzunoğlu, İbrahi̇m Güneş, Mukden Uğur Jan 2011

Analysis Of Frequency Characteristics Of Electrical Arcs On The Insulating Sheath Of The Adss Fiber Optic Cables, Cengi̇z Polat Uzunoğlu, İbrahi̇m Güneş, Mukden Uğur

Turkish Journal of Electrical Engineering and Computer Sciences

The insulating outer-sheath of ADSS (All dielectric self supporting) cables used on high voltage transmission lines are often subjected to various environmental effects. The ageing process of cable sheath can be investigated by using the dry-band arcing test method under laboratory conditions. Dry-band arcing is the most common technique to determine the ageing period of insulating materials. Environmental effects such as rain, humidity, dew and ice produce various amounts of wet regions on the cable surface. Electrical arcs and hence degradations are occurred on the cable surface due to the enhanced electrical field with formation of wet regions. In this …


Cooperative Diversity With Continuous Phase Modulation, Ni̇yazi̇ Odabaşioğlu Jan 2011

Cooperative Diversity With Continuous Phase Modulation, Ni̇yazi̇ Odabaşioğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, there has been a vast amount of research on cooperative diversity due to its potential capacity increase. Almost all of the research has been based on linear modulation formats such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM). On the other hand, continuous phase modulation (CPM) promises impressive advantages relative to linear modulations for wireless communication systems. In this paper, a cooperative diversity scheme with space-time coded (STC) CPM is introduced. Both amplify-and-forward (AF) and decode-and-forward (DF) modes were considered for cooperation. Simulation results showed that the proposed system is very suitable for wireless fading channels, …