A Model Based Nonlinear Adaptive Controller For The Passive Bilateral Telerobotic System,
2010
TÜBİTAK
A Model Based Nonlinear Adaptive Controller For The Passive Bilateral Telerobotic System, Ufuk Özbay, Erkan Zergeroğlu, İlyas Kandemi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
IIn this paper, we propose a new adaptive controller scheme for the bilateral telerobotic/teleoperation systems. The proposed controller achieves asymptotic tracking despite the parametric uncertainties associated with both master and slave robots while ensuring the passivity of the closed loop system. Extensive simulation studies are presented to illustrate the feasibility and efficiency of the proposed adaptive controller.
Simultaneous Rotor And Stator Resistance Estimation Of Squirrel Cage Induction Machine With A Single Extended Kalman Filter,
2010
TÜBİTAK
Simultaneous Rotor And Stator Resistance Estimation Of Squirrel Cage Induction Machine With A Single Extended Kalman Filter, Eşref Emre Özsoy, Meti̇n Gökaşan, Ovsanna Seta Estrada
Turkish Journal of Electrical Engineering and Computer Sciences
Accurate knowledge of rotor and stator resistance variations in a squirrel-cage induction motor (SCIM) is crucial for the performance of sensorless control of SCIM over a wide range of speeds. This study seeks to address this issue with a single Extended Kalman Filter (EKF) based solution, which is also known to have accuracy limitations when a high number of parameters/states are estimated with a limited number of inputs. To this aim, different from the author's previous approach in operating several EKFs in an alternating manner (the so-called braided EKF), an 8^{th}-order EKF is implemented in this study to test its …
Analysis And Estimation Of Motion Transmission Errors Of A Timing Belt Drive,
2010
TÜBİTAK
Analysis And Estimation Of Motion Transmission Errors Of A Timing Belt Drive, Ergi̇n Kiliç, Meli̇k Dölen, Ahmet Buğra Koku
Turkish Journal of Electrical Engineering and Computer Sciences
This paper focuses on viable position estimation schemes for timing belt drives where the position of the carriage (load) is to be determined via reference models receiving input from a position sensor attached to the actuator of the timing belt. A detailed analysis of the transmission error sources is presented, and a number of relevant mathematical models are developed using a priori knowledge of the process. This paper demonstrates that such schemes are very effective when the drive system is not subjected to external loads and operating conditions do not change considerably i.e. ambient temperature, belt tension.
Precise Position Control Using Shape Memory Alloy Wires,
2010
TÜBİTAK
Precise Position Control Using Shape Memory Alloy Wires, Burcu Dönmez, Bülent Özkan, Fevzi̇ Suat Kadioğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Shape memory alloys (SMAs) are active metallic ``smart'' materials used as actuators and sensors in high technology smart systems [1]. The term shape memory refers to ability of certain materials to ``remember'' a shape, even after rather severe deformations: once deformed at low temperatures, these materials will stay deformed until heated, whereupon they will return to their original, pre-deformed ``learned'' shape [2]. This property can be used to generate motion and/or force in electromechanical devices and micro-machines. However, the accuracy of SMA actuators is severely limited by their highly nonlinear stimulus-response characteristics. In this work, modeling, simulation, and experimental efforts …
Design And Evaluation Of A Linear Switched Reluctance Actuator For Positioning Tasks,
2010
TÜBİTAK
Design And Evaluation Of A Linear Switched Reluctance Actuator For Positioning Tasks, António Espírito Santo, Rosário Calado, Carlos Cabrita
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the development of a new linear switched reluctance actuator and confirms its applicability to perform positioning tasks. After the explanation of the actuator working principle and the presentation of its electromechanical topology, an analysis is accomplished using a finite elements tool. Based on the theoretical results, an experimental prototype that can develop 150 N was constructed. Its behaviour is observed under two different control methods implemented with microcontrollers. Initially, position is controlled applying a single pulse-driving scheme. Meanwhile, significant improvements are obtained with the introduction of a sliding-mode controller, allowing movements with 1 mm of resolution.
Detection Of Static Eccentricity For Permanent Magnet Synchronous Motors Using The Coherence Analysis,
2010
TÜBİTAK
Detection Of Static Eccentricity For Permanent Magnet Synchronous Motors Using The Coherence Analysis, Mehmet Akar, Sezai̇ Taşkin, Şahi̇n Serhat Şeker, İlyas Çankaya
Turkish Journal of Electrical Engineering and Computer Sciences
This paper reports on work to detect the static eccentricity faults for permanent magnet synchronous motor (PMSM) using spectral analysis methods. Measurements are carried out by collecting the stator current and voltage, torque and speed for healthy and faulty cases of the motor. Static eccentricity case is formed by changing the rotor position in the manner of sliding the shaft on a horizontal axis. As a result of the spectral analysis for the motor currents, side band effects appeared at around the fundamental frequency are determined as a most important indicator of the eccentricity. In addition to this determination, the …
Using Covariates For Improving The Minimum Redundancy Maximum Relevance Feature Selection Method,
2010
TÜBİTAK
Using Covariates For Improving The Minimum Redundancy Maximum Relevance Feature Selection Method, Olcay Kurşun, Cemal Okan Şakar, Oleg Favorov, Ni̇zametti̇n Aydin, Sadik Fi̇kret Gürgen
Turkish Journal of Electrical Engineering and Computer Sciences
Maximizing the joint dependency with a minimum size of variables is generally the main task of feature selection. For obtaining a minimal subset, while trying to maximize the joint dependency with the target variable, the redundancy among selected variables must be reduced to a minimum. In this paper, we propose a method based on recently popular minimum Redundancy-Maximum Relevance} (mRMR) criterion. The experimental results show that instead of feeding the features themselves into mRMR, feeding the covariates improves the feature selection capability and provides more expressive variable subsets.
Usage Of Spline Interpolation In Catheter-Based Cardiac Mapping,
2010
TÜBİTAK
Usage Of Spline Interpolation In Catheter-Based Cardiac Mapping, Bülent Yilmaz, Uğur Cunedi̇oğlu, Engi̇n Baysoy
Turkish Journal of Electrical Engineering and Computer Sciences
Due to their minimal invasiveness catheters are highly preferred in cardiac mapping techniques used in the source localization of rhythm disturbances in the heart. In cardiac mapping, standard steerable catheters and multielectrode basket catheters are the two alternatives for the characterization of the underlying tissue on the inner (endocardium) and outer (epicardium) surfaces of the heart. As with any discrete sampling technique, an important question for catheter-based cardiac mapping is how to determine values at locations from which direct measurements are not available. Interpolation is the most common approach for providing values at unmeasured sites using the available measurements. In …
Delta-Sigma Subarray Beamforming For Ultrasound Imaging,
2010
TÜBİTAK
Delta-Sigma Subarray Beamforming For Ultrasound Imaging, Hasan Şaki̇r Bi̇lge
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, an ultrasonic digital beamformer based on subarray processing of 1-bit delta-sigma (\Delta \Sigma ) oversampled echo signals is presented. The single-bit oversampling \Delta \Sigma conversion simplifies the coherent processing in beamforming with improved timing accuracy. Subarray processing also aims to simplify the beamforming complexity, where the partial-beam sums (low-resolution beams) are acquired from small subarrays, and then these partial beams are coherently processed for producing high-resolution beams. In the \Delta \Sigma subarray beamforming, the \Delta \Sigma coded echo signals are summed over the subarray channels, and then these partial beam-sums are first \Delta \Sigma demodulated, then processed …
Design Of Optimal Sampling Times For Pharmacokinetic Trials Via Spline Approximation,
2010
TÜBİTAK
Design Of Optimal Sampling Times For Pharmacokinetic Trials Via Spline Approximation, Musa Hakan Asyali
Turkish Journal of Electrical Engineering and Computer Sciences
Understanding and comparison of different drug delivery formulations are based on pharmacokinetic parameters (PKP) such as area under curve, maximum concentration, and time to reach maximum concentration. Accurate estimation of PKP is of critical importance in capturing drug absorption and elimination characteristics and in reaching bioequivalence decisions. Since PKP are estimated from a limited number of samples, the timing of the samples directly influences the accuracy of estimation. Optimization of the sampling times may not only increase the accuracy of PKP estimation, but also reduce the number of samples to be drawn, which in turn lessens the inconvenience to the …
Optimal Feature Selection For 3d Facial Expression Recognition Using Coarse-To-Fine Classification,
2010
TÜBİTAK
Optimal Feature Selection For 3d Facial Expression Recognition Using Coarse-To-Fine Classification, Hamit Soyel, Hasan Demirel
Turkish Journal of Electrical Engineering and Computer Sciences
Automatic facial expression recognition for novel individuals from 3D face data is a challenging task in pattern analysis. This paper describes a feature selection process for pose-invariant 3D facial expression recognition. The process provides a lower dimensional subspace representation, which is optimized to improve the classification accuracy, retrieved from geometrical localization of facial feature points to classify facial expressions. Fisher criterion-based approach is adopted to provide a basis for the optimal selection of features. Two-stage probabilistic neural network architecture is employed as a classifier to recognize the facial expressions. In the first stage, which can be regarded as the coarse …
Fast Computation Of Determination Of The Prime Implicants By A Novel Near Minimum Minimization Method,
2010
TÜBİTAK
Fast Computation Of Determination Of The Prime Implicants By A Novel Near Minimum Minimization Method, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli
Turkish Journal of Electrical Engineering and Computer Sciences
In this study proposed is an off-set-based direct-cover near-minimum minimization method for single-output Boolean functions represented in a sum-of-products form. To obtain the complete set of prime implicants including given on-cube (on-minterm), the proposed method uses off-cubes (off-minterms) expanded by this On-cube. The amount of temporary results produced by this method does not exceed the size of the off-set. To make fast computation, we used logic operations instead of standard operations. Expansion off-cubes, commutative absorption operations and intersection operations are realized by logic operations for fast computation. The proposed minimization method is tested on several different kinds of problems and …
A Second Order Approximation To Reduce The Complexity Of Ldpc Decoders Based On Gallager's Approach,
2010
TÜBİTAK
A Second Order Approximation To Reduce The Complexity Of Ldpc Decoders Based On Gallager's Approach, Aykut Kalaycioğlu, Oktay Üreten, H. Gökhan İlk
Turkish Journal of Electrical Engineering and Computer Sciences
A piece-wise second order approximation to the f (x) = -log [tanh (x/2)] function is proposed to reduce the computational complexity of LDPC decoder's utilizing Log-Likelihood Ratio Belief Propagation (LLR-BP) algorithm based on Gallager's approach. Simulation results show that the proposed low complexity approximation doesn't cause BER performance degradation.
Performance Analysis Of Swarm Optimization Approaches For The Generalized Assignment Problem In Multi-Target Tracking Applications, Ali̇ Önder Bozdoğan, Asim Egemen Yilmaz, Murat Efe
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this study is to investigate the suitability of selected swarm optimization algorithms to the generalized assignment problem as encountered in multi-target tracking applications. For this purpose, we have tested variants of particle swarm optimization and ant colony optimization algorithms to solve the 2D generalized assignment problem with simulated dense and sparse measurement/track matrices and compared their performance to that of the auction algorithm. We observed that, although with some modification swarm optimization algorithms provide improvement in terms of speed, they still fall behind the auction algorithm in finding the optimum solution to the problem. Among the investigated …
Stpso: Strengthened Particle Swarm Optimization,
2010
TÜBİTAK
Stpso: Strengthened Particle Swarm Optimization, Ai̇şe Zülal Şevkli̇, Fati̇h Erdoğan Sevi̇lgen
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we present a novel approach to strengthen Particle Swarm Optimization (PSO). PSO is a population-based metaheuristic that takes advantage of individual memory and social cooperation in a swarm. It has been applied to a variety of optimization problems because of its simplicity and fast convergence. However, straightforward application of PSO suffers from premature convergence and lack of intensification around the local best locations. To rectify these problems, we modify update procedure for the best particle in the swarm and propose a simple and random moving strategy. We perform a Reduced Variable Neighborhood Search (RVNS) based local search …
Defending Privacy: The Development And Deployment Of A Darknet,
2010
Technological University Dublin
Defending Privacy: The Development And Deployment Of A Darknet, Conor Mcmanamon, Fredrick Mtenzi
Conference papers
New measures imposed by governments, Internet service providers and other third parties which threaten the state of privacy are also opening new avenues to protecting it. The unwarranted scrutiny of legitimate services such as file hosters and the BitTorrent protocol, once relatively unknown to the casual Internet user, is becoming more obvious. The darknet is a rising contender against these new measures and will preserve the default right to privacy of Internet users. A darknet is defined in the context of file sharing as a network which operates on top of another network such as the Internet for the purpose …
Helmsman, Set A Course : Using A Compass And Rfid Tags For Indoor Localisation And Navigation,
2010
Technological University Dublin
Helmsman, Set A Course : Using A Compass And Rfid Tags For Indoor Localisation And Navigation, Yan Li, Brian Mac Namee, John D. Kelleher
Conference papers
Localisation and navigation are still two of the most important issues in mobile robotics. In certain indoor application scenarios RFID (radio frequency identification)-based absolute localisation has been found to be especially successful in supporting navigation. In this paper we evaluate the feasibility of an RFID and compass based approach to robot localisation and navigation for indoor environments that are dominated by corridors. We describe our system and evaluate its performance in a small, but full-scale, test environment.
Evaluating Sensorineural Hearing Loss With An Auditory Nerve Model Using A Mean Structural Similarity Measure,
2010
Technological University Dublin
Evaluating Sensorineural Hearing Loss With An Auditory Nerve Model Using A Mean Structural Similarity Measure, Andrew Hines, Naomi Harte
Conference papers
Hearing loss research has traditionally been based on perceptual criteria, speech intelligibility and threshold levels. The development of computational models of the auditory-periphery has allowed experimentation via simulation to provide quantitative, repeatable results at a more granular level than would be practical with clinical research on human subjects. This work seeks to create an objective measure to automate this inspection process and ranks hearing losses based on auditory-nerve discharge patterns. A systematic way of assessing phonemic degradation using the outputs of an auditory nerve model for a range of sensorineural hearing losses would aid in rapid prototyping development of speech-processing …
