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2010

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Articles 691 - 705 of 705

Full-Text Articles in Computer Engineering

Using Covariates For Improving The Minimum Redundancy Maximum Relevance Feature Selection Method, Olcay Kurşun, Cemal Okan Şakar, Oleg Favorov, Ni̇zametti̇n Aydin, Sadik Fi̇kret Gürgen Jan 2010

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, Bülent Yilmaz, Uğur Cunedi̇oğlu, Engi̇n Baysoy Jan 2010

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 …


Design Of Optimal Sampling Times For Pharmacokinetic Trials Via Spline Approximation, Musa Hakan Asyali Jan 2010

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 …


Fast Computation Of Determination Of The Prime Implicants By A Novel Near Minimum Minimization Method, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli Jan 2010

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, Aykut Kalaycioğlu, Oktay Üreten, H. Gökhan İlk Jan 2010

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.


Optimal Feature Selection For 3d Facial Expression Recognition Using Coarse-To-Fine Classification, Hamit Soyel, Hasan Demirel Jan 2010

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 …


Performance Analysis Of Swarm Optimization Approaches For The Generalized Assignment Problem In Multi-Target Tracking Applications, Ali̇ Önder Bozdoğan, Asim Egemen Yilmaz, Murat Efe Jan 2010

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 …


Fuzzy Adaptive Neural Network Approach To Path Loss Prediction In Urban Areas At Gsm-900 Band, Türkan Erbay Dalkiliç, Berna Yeşi̇m Hanci, Ayşen Apaydin Jan 2010

Fuzzy Adaptive Neural Network Approach To Path Loss Prediction In Urban Areas At Gsm-900 Band, Türkan Erbay Dalkiliç, Berna Yeşi̇m Hanci, Ayşen Apaydin

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents the results of the Adaptive-Network Based Fuzzy Inference System (ANFIS) for the prediction of path loss in a specific urban environment. A new algorithm based ANFIS for tuning the path loss model is introduced in this work. The performance of the path loss model which is obtained from proposed algorithm is compared to the Bertoni-Walfisch model, which is one of the best studied for propagation analysis involving buildings. This comparison is based on the mean square error between predicted and measured values. According to the indicated error criterion, the errors related to the predictions that are obtained …


Stpso: Strengthened Particle Swarm Optimization, Ai̇şe Zülal Şevkli̇, Fati̇h Erdoğan Sevi̇lgen Jan 2010

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 …


Behaviors Of Real-Time Schedulers Under Resource Modification And A Steady Scheme With Bounded Utilization, Refi̇k Samet, Orhan Fi̇kret Duman Jan 2010

Behaviors Of Real-Time Schedulers Under Resource Modification And A Steady Scheme With Bounded Utilization, Refi̇k Samet, Orhan Fi̇kret Duman

Turkish Journal of Electrical Engineering and Computer Sciences

In this article we present an analysis for task models having random resource needs and different arrival patterns. In hard real-time environments like avionic systems or nuclear reactors, the inputs to the system are obtained from real world by using sensors. And it is highly possible for a task to have different resource needs for each period according to these changing conditions of real world. We made an analysis of schedulers for task models having random resources in each period. Since feasibility tests for usual task models are just limited to some specific schedulers and arrival patterns, we made our …


Information Theoretic Approach For Assessing Image Fidelity In Photon-Counting Arrays, Srikanth R. Narravula, Majeed M. Hayat, Bahram Javidi Jan 2010

Information Theoretic Approach For Assessing Image Fidelity In Photon-Counting Arrays, Srikanth R. Narravula, Majeed M. Hayat, Bahram Javidi

Electrical and Computer Engineering Faculty Research and Publications

The method of photon-counting integral imaging has been introduced recently for three-dimensional object sensing, visualization, recognition and classification of scenes under photon-starved conditions. This paper presents an information-theoretic model for the photon-counting imaging (PCI) method, thereby providing a rigorous foundation for the merits of PCI in terms of image fidelity. This, in turn, can facilitate our understanding of the demonstrated success of photon-counting integral imaging in compressive imaging and classification. The mutual information between the source and photon-counted images is derived in a Markov random field setting and normalized by the source-image’s entropy, yielding a fidelity metric that is between …


Measurement And Modeling Of Infrared Nonlinear Absorption Coefficients And Laser-Induced Damage Thresholds In Ge And Gasb, T. J. Wagner, M. A. Bohn, Ronald A. Coutu Jr., L. P. Gonzalez, J. M. Murray, K. L. Schepler, S. Guha Jan 2010

Measurement And Modeling Of Infrared Nonlinear Absorption Coefficients And Laser-Induced Damage Thresholds In Ge And Gasb, T. J. Wagner, M. A. Bohn, Ronald A. Coutu Jr., L. P. Gonzalez, J. M. Murray, K. L. Schepler, S. Guha

Electrical and Computer Engineering Faculty Research and Publications

Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond …


A Machine Learning Approach To Hierarchical Categorisation Of Auditory Objects, William Coleman, Sarah Jane Delany, Charlie Cullen, Ming Yan Dr. Jan 2010

A Machine Learning Approach To Hierarchical Categorisation Of Auditory Objects, William Coleman, Sarah Jane Delany, Charlie Cullen, Ming Yan Dr.

Articles

With the advent of new audio delivery technologies comes opportunities and challenges for content creators and providers. The proliferation of consumption modes (stereo headphones, home cinema systems, ‘hearables’), media formats (mp3, CD, video and audio streaming) and content types (gaming, music, drama & current affairs broadcasting) has given rise to a complicated landscape where content must often be adapted for multiple end-use scenarios. The concept of object-based audio envisages content delivery not via a fixed mix but as a series of auditory objects which can then be controlled either by consumers or by content creators & providers via accompanying metadata. …


Using Virtual Reality To Enhance Electrical Safety And Design In The Built Environment, Martin Barrett, Jonathan Blackledge, Eugene Coyle Jan 2010

Using Virtual Reality To Enhance Electrical Safety And Design In The Built Environment, Martin Barrett, Jonathan Blackledge, Eugene Coyle

Articles

Electricity and the inherent risks associated with its use in the built environment have long since been a priority for the electrical services industry and also the general public who must live and work in this environment. By its nature virtual reality has the advantage of being safe for both the user and equipment. In addition, it offers the user an opportunity to be exposed to a range of scenarios and conditions that either occur infrequently or are hazardous to replicate. This paper presents a prototype desktop virtual reality model, to enhance electrical safety and design in the built environment. …


Transmitter Optimization In Multiuser Wireless Systems With Quality Of Service Constraints, Danda B. Rawat Jan 2010

Transmitter Optimization In Multiuser Wireless Systems With Quality Of Service Constraints, Danda B. Rawat

Electrical & Computer Engineering Theses & Dissertations

In this dissertation, transmitter adaptation for optimal resource allocation in wireless communication systems are investigated. First, a multiple access channel model is considered where many transmitters communicate with a single receiver. This scenario is a basic component of a. wireless network in which multiple users simultaneously access the resources of a wireless service provider. Adaptive algorithms for transmitter optimization to meet Quality-of-Service (QoS) requirements in a distributed manner are studied. Second, an interference channel model is considered where multiple interfering transmitter-receiver pairs co-exist such that a given transmitter communicates with its intended receiver in the presence of interference from other …