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2015

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Articles 1921 - 1950 of 2105

Full-Text Articles in Computer Sciences

Weaving Risk Identification Into Crowdsourcing Lifecycle, Faouzi Kamoun, Dima Alhadidi, Zakaria Maamar Jan 2015

Weaving Risk Identification Into Crowdsourcing Lifecycle, Faouzi Kamoun, Dima Alhadidi, Zakaria Maamar

All Works

© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license. Crowdsourcing enables companies and individuals as well to tap into the versatile knowledge, creativity, and talent of a large population of crowd contributors. Yet, crowdsourcing can expose companies to a myriad of risks that can have drastic impact on the profitability and competitive position. This paper presents a Risk Breakdown Structure (RBS) of crowdsourcing projects that spans the entire project's lifecycle. The paper first reports on a lifecycle model that captures the main phases of a crowdsourcing project. It then identifies …

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Graph-Based Regularization In Machine Learning: Discovering Driver Modules In Biological Networks, Xi Gao Jan 2015

Graph-Based Regularization In Machine Learning: Discovering Driver Modules In Biological Networks, Xi Gao

Theses and Dissertations

Curiosity of human nature drives us to explore the origins of what makes each of us different. From ancient legends and mythology, Mendel's law, Punnett square to modern genetic research, we carry on this old but eternal question. Thanks to technological revolution, today's scientists try to answer this question using easily measurable gene expression and other profiling data. However, the exploration can easily get lost in the data of growing volume, dimension, noise and complexity. This dissertation is aimed at developing new machine learning methods that take data from different classes as input, augment them with knowledge of feature relationships, …

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Saliency-Guided Color-To-Gray Conversion Using Region-Based Optimization, Hao Du, Shengfeng He, Bin Sheng, Lizhuang Ma, Rynson W.H. Lau Jan 2015

Saliency-Guided Color-To-Gray Conversion Using Region-Based Optimization, Hao Du, Shengfeng He, Bin Sheng, Lizhuang Ma, Rynson W.H. Lau

Research Collection School Of Computing and Information Systems

Image decolorization is a fundamental problem for many real-world applications, including monochrome printing and photograph rendering. In this paper, we propose a new color-to-gray conversion method that is based on a region-based saliency model. First, we construct a parametric color-to-gray mapping function based on global color information as well as local contrast. Second, we propose a region-based saliency model that computes visual contrast among pixel regions. Third, we minimize the salience difference between the original color image and the output grayscale image in order to preserve contrast discrimination. To evaluate the performance of the proposed method in preserving contrast in …

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Ambiguous Optimistic Fair Exchange: Definition And Constructions, Qiong Huang, Guomin Yang, Duncan S. Wong, Willy Susilo Jan 2015

Ambiguous Optimistic Fair Exchange: Definition And Constructions, Qiong Huang, Guomin Yang, Duncan S. Wong, Willy Susilo

Research Collection School Of Computing and Information Systems

Optimistic fair exchange (OFE) is a protocol for solving the problem of exchanging items or services in a fair manner between two parties, a signer and a verifier, with the help of an arbitrator which is called in only when a dispute happens between the two parties. In almost all the previous work on OFE, after obtaining a partial signature from the signer, the verifier can present it to others and show that the signer has indeed committed itself to something corresponding to the partial signature even prior to the completion of the transaction. In some scenarios, this capability given …

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Community Discovery From Social Media By Low-Rank Matrix Recovery, Jinfeng Zhuang, Mei Tao, Steven C. H. Hoi, Xian-Sheng Hua, Yongdong Zhang Jan 2015

Community Discovery From Social Media By Low-Rank Matrix Recovery, Jinfeng Zhuang, Mei Tao, Steven C. H. Hoi, Xian-Sheng Hua, Yongdong Zhang

Research Collection School Of Computing and Information Systems

The pervasive usage and reach of social media have attracted a surge of attention in the multimedia research community. Community discovery from social media has therefore become an important yet challenging issue. However, due to the subjective generating process, the explicitly observed communities (e.g., group-user and user-user relationship) are often noisy and incomplete in nature. This paper presents a novel approach to discovering communities from social media, including the group membership and user friend structure, by exploring a low-rank matrix recovery technique. In particular, we take Flickr as one exemplary social media platform. We first model the observed indicator matrix …

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Automatic, High Accuracy Prediction Of Reopened Bugs, Xin Xia, David Lo, Emad Shihab, Xinyu Wang, Bo Zhou Jan 2015

Automatic, High Accuracy Prediction Of Reopened Bugs, Xin Xia, David Lo, Emad Shihab, Xinyu Wang, Bo Zhou

Research Collection School Of Computing and Information Systems

Bug fixing is one of the most time-consuming and costly activities of the software development life cycle. In general, bugs are reported in a bug tracking system, validated by a triage team, assigned for someone to fix, and finally verified and closed. However, in some cases bugs have to be reopened. Reopened bugs increase software maintenance cost, cause rework for already busy developers and in some cases even delay the future delivery of a software release. Therefore, a few recent studies focused on studying reopened bugs. However, these prior studies did not achieve high performance (in terms of precision and …

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Push Or Pull? A Website's Strategic Choice Of Content Delivery Mechanism, Dan Ma Jan 2015

Push Or Pull? A Website's Strategic Choice Of Content Delivery Mechanism, Dan Ma

Research Collection School Of Computing and Information Systems

Really simple syndication (RSS) technology enables an alternative delivery mechanism for online content. Instead of waiting passively for users to pull online content out, websites can push it to potential users through RSS. This is expected to significantly affect user behavior, website profitability, and market equilibrium. This research uses an economic model to study the impact of RSS adoption and examine whether it increases a website’s profit and competitive advantage. The findings are intriguing: they demonstrate that RSS can either increase or decrease website profit. In a competitive context, RSS adoption can actually be a disadvantage; in some cases, it …

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Improving Software Quality And Productivity Leveraging Mining Techniques: [Summary Of The Second Workshop On Software Mining, At Ase 2013], Ming Li, Hongyu Zhang, David Lo, Lucia Lucia Jan 2015

Improving Software Quality And Productivity Leveraging Mining Techniques: [Summary Of The Second Workshop On Software Mining, At Ase 2013], Ming Li, Hongyu Zhang, David Lo, Lucia Lucia

Research Collection School Of Computing and Information Systems

The second International Workshop on Software Mining (Soft-mine) was held on the 11th of November 2013. The workshop was held in conjunction with the 28th IEEE/ACM International Conference on Automated Software Engineering (ASE) in Silicon Valley, California, USA. The workshop has facilitated researchers who are interested in mining various types of software-related data and in applying data mining techniques to support software engineering tasks. During the workshop, seven papers on software mining and behavior models, execution trace mining, and bug localization and fixing were presented. One of the papers received the best paper award. Furthermore, there were two invited talk …

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Are Features Equally Representative? A Feature-Centric Recommendation, Chenyi Zhang, Ke Wang, Ee-Peng Lim, Qinneng Xu, Jianling Sun, Hongkun Yu Jan 2015

Are Features Equally Representative? A Feature-Centric Recommendation, Chenyi Zhang, Ke Wang, Ee-Peng Lim, Qinneng Xu, Jianling Sun, Hongkun Yu

Research Collection School Of Computing and Information Systems

Typically a user prefers an item (e.g., a movie) because she likes certain features of the item (e.g., director, genre, producer). This observation motivates us to consider a feature-centric recommendation approach to item recommendation: instead of directly predicting the rating on items, we predict the rating on the features of items, and use such ratings to derive the rating on an item. This approach offers several advantages over the traditional item-centric approach: it incorporates more information about why a user chooses an item, it generalizes better due to the denser feature rating data, it explains the prediction of item ratings …

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Optimization Of Grid Connected Micro-Grid Consisting Of Pv/Fc/Uc With Considered Frequency Control, Hamid Hasanzadehfard, Masoud Moghaddas-Tafreshi, Sayed Mehdi Hakimi Jan 2015

Optimization Of Grid Connected Micro-Grid Consisting Of Pv/Fc/Uc With Considered Frequency Control, Hamid Hasanzadehfard, Masoud Moghaddas-Tafreshi, Sayed Mehdi Hakimi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, ultracapacitors are used as short-term storages for the frequency control of grid-connected microgrid that consists of photovoltaic panels, fuel cells, and the battery packs as long-term storages. Fuel cells and battery packs have delays in load tracking; therefore, ultracapacitors are used to compensate for the sudden power fluctuations in the microgrid that occur due to the output power uncertainty of the PV arrays and the loads required in the microgrid, as well as the sudden interruption of the main grid. The microgrid consists of interruptible and uninterruptible loads. When the total produced power in the microgrid, in …

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Sensitivity Analysis And Optimum Design For The Stator Of Synchronous Reluctance Machines Using The Coupled Finite Element And Taguchi Methods, Hossein Azizi, Abolfazl Vahedi Jan 2015

Sensitivity Analysis And Optimum Design For The Stator Of Synchronous Reluctance Machines Using The Coupled Finite Element And Taguchi Methods, Hossein Azizi, Abolfazl Vahedi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an investigation of the effect and optimization of stator geometry design parameters on the performance of synchronous reluctance machines (SynRMs). The level of importance of the stator design variable on the characteristic of the SynRM is determined using both the Taguchi method and a parametric analysis. An optimum design parameter combination is obtained using sensitivity analysis along with signal-to-noise ratio results. The 2-dimensional finite element model (FEM) of a SynRM is used to perform a sensitivity analysis and construct a Taguchi design of the experiment. The FEM simulation results confirm that the performance of the SynRM can …

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Investigation Of Respiratory And Heart Rate Variability In Hypertensive Patients, Ramazan Aldemi̇r, Mahmut Tokmakçi Jan 2015

Investigation Of Respiratory And Heart Rate Variability In Hypertensive Patients, Ramazan Aldemi̇r, Mahmut Tokmakçi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, in order to examine the effect of respiration on heart rate variability (HRV), signal processing analyses were performed between the signal received from the periodic movement of the chest of respiration and the pulse plethysmograph (PPS) signal, providing the calculation of both the time and frequency behavior of HRV and also including pulse rate information at the same time. Respiration is used as the comparison parameter in both healthy subjects and in hypertensive patients, not only with the time and frequency components of the HRV, but also with the galvanic skin resistance simultaneously taken with body temperature …

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Design Of A Novel Usb Crypto Bridge Device, Orhan Şengül Jan 2015

Design Of A Novel Usb Crypto Bridge Device, Orhan Şengül

Turkish Journal of Electrical Engineering and Computer Sciences

Information technologies have emerging use of portable drives. Hence, the readability and security of the content is at great risk in the event that it is lost or stolen. An effective solution to this issue is the use of removable disks in encrypted form. In this paper, a novel USB device that has cryptobridge capability is proposed.

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A Novel Efficient Model For The Power Flow Analysis Of Power Systems, Amir Safdarian, Mahmud Fotuhi Firuzabad, Farrokh Aminifar Jan 2015

A Novel Efficient Model For The Power Flow Analysis Of Power Systems, Amir Safdarian, Mahmud Fotuhi Firuzabad, Farrokh Aminifar

Turkish Journal of Electrical Engineering and Computer Sciences

The overall system status calculated by power flow analysis is the most basic information used for all decisions taken by power system operators and planners. While conventional AC power flow solutions are computationally tractable, approximate DC models are employed in many applications, such as optimal power flow studies and unit commitment problems, mainly due to the linear nature of DC models. These models do not provide any information on the reactive power and voltage magnitude quantities and occasionally inaccurate results of the active power values. This paper presents an efficient power flow approach compromising both the conflicting aspects of speed …

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Adaptive Network-Based Inference System Models On Multiband Patch Antenna Design, Erdem Demi̇rci̇oğlu, Murat Hüsnü Sazli, Orhan Şengül, Şehabeddi̇n Taha İmeci̇, Hakki Alparslan Ilgin Jan 2015

Adaptive Network-Based Inference System Models On Multiband Patch Antenna Design, Erdem Demi̇rci̇oğlu, Murat Hüsnü Sazli, Orhan Şengül, Şehabeddi̇n Taha İmeci̇, Hakki Alparslan Ilgin

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an adaptive network-based fuzzy inference system (ANFIS) for multiband microstrip patch antenna (MMPA) modeling is proposed. The MMPA includes a single patch with inverted L-shaped stubs on the edges. The antenna production process needs iterative runs of the electromagnetic (EM) simulator, fabricating and testing the simulated antenna to find the optimum geometry. Production processes (design, simulation, fabrication, and testing) and the cost computation time add to the overall manufacturing expenses. A computer-aided modeling approach using the ANFIS is developed and trained with data acquired from the EM simulators, Sonnet Suites and AWR AXIEM, and measurement data. The …

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Mras-Based Sensorless Speed Backstepping Control For Induction Machine, Using A Flux Sliding Mode Observer, Mohamed Moutchou, Ahmed Abbou, Hassan Mahmoudi Jan 2015

Mras-Based Sensorless Speed Backstepping Control For Induction Machine, Using A Flux Sliding Mode Observer, Mohamed Moutchou, Ahmed Abbou, Hassan Mahmoudi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an induction machine rotor speed and rotor flux control using a sensorless backstepping control scheme is discussed. The most interesting point of this technique is that it deals with the nonlinearity of a high-order system by using the virtual control variable to make this system simple, and thus the control outputs can be derived step by step through appropriate Lyapunov functions. To avoid the use of a mechanical sensor, the rotor speed estimation is made by an observer using the model reference adaptive system (MRAS) technique; in order to estimate rotor flux, a sliding mode observer is …

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Designing And Implementing A Reliable Thermal Monitoring System Based On The 1-Wire Protocol On Fpga For A Leo Satellite, Reza Omidi Gosheblagh, Karim Mohammadi Jan 2015

Designing And Implementing A Reliable Thermal Monitoring System Based On The 1-Wire Protocol On Fpga For A Leo Satellite, Reza Omidi Gosheblagh, Karim Mohammadi

Turkish Journal of Electrical Engineering and Computer Sciences

Thermal control and monitoring is one of the most important factors in the design of satellite systems. An appropriate thermal design should make sure that the satellite's sensitive components remain in their nominated range, even under the vacuum condition of outer space. To achieve this purpose, a reliable and stable monitoring system is required. This paper proposes a monitoring system based on the 1-wire protocol, which provides the reliability requirements in the sensor networking and bus controller sections. In the networking section, we outline some practical topologies and discuss on their complexity and reliability. Despite the fact that the point-to-point …

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Short-Term Load Forecasting Using Mixed Lazy Learning Method, Seyed-Masoud Barakati, Ali Akbar Gharaveisi, Seyed-Mohammad Reza Rafiei Jan 2015

Short-Term Load Forecasting Using Mixed Lazy Learning Method, Seyed-Masoud Barakati, Ali Akbar Gharaveisi, Seyed-Mohammad Reza Rafiei

Turkish Journal of Electrical Engineering and Computer Sciences

A novel short-term load forecasting method based on the lazy learning (LL) algorithm is proposed. The LL algorithm's input data are electrical load information, daily electricity consumption patterns, and temperatures in a specified region. In order to verify the ability of the proposed method, a load forecasting problem, using the Pennsylvania-New Jersey-Maryland Interconnection electrical load data, is carried out. Three LL models are proposed: constant, linear, and mixed models. First, the performances of the 3 developed models are compared using the root mean square error technique. The best technique is then selected to compete with the state-of-the-art neural network (NN) …

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Temporal Logic Extension For Self-Referring, Nonexistence, Multiple Recurrence, And Anterior Past Events, Şadi̇ Evren Şeker Jan 2015

Temporal Logic Extension For Self-Referring, Nonexistence, Multiple Recurrence, And Anterior Past Events, Şadi̇ Evren Şeker

Turkish Journal of Electrical Engineering and Computer Sciences

This study focuses on the possible extensions of current temporal logics. In this study, 4 extensions are proposed: self-referring events, nonexisting events, multiple recurrence of events, and an improvement on anterior past events. Each of these extensions is on a different level of temporal logics. The main motivation behind the extensions is the temporal analysis of Turkish. Similar to temporal logic studies built on other natural languages, like French, Ukrainian, Italian, Korean, English, or Romanian, this is the first time that the Turkish language has been deeply questioned in the sense of computable temporal logic using the view of a …

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Discrete-Time Modeling Of Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer, Salman Kurtulan Jan 2015

Discrete-Time Modeling Of Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer, Salman Kurtulan

Turkish Journal of Electrical Engineering and Computer Sciences

The problem of discrete-time modeling of the lumped-parameter Hamiltonian systems is considered for engineering applications. Hence, a novel gradient-based method is presented, exploiting the discrete gradient concept and the forward Euler discretization under the assumption of the continuous Hamiltonian model is known. It is proven that the proposed discrete-time model structure defines a symplectic difference system and has the energy-conserving property under some conditions. In order to provide alternate discrete-time models, 3 different discrete-gradient definitions are given. The proposed models are convenient for the design of sampled-data controllers. All of the models are considered for several well-known Hamiltonian systems and …

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Control Of Oxygen Excess Ratio In A Pem Fuel Cell System Using High-Order Sliding-Mode Controller And Observer, Seyed Mehdi Rakhtala, Abolfazl Ranjbar Noei, Reza Ghaderi, Elio Usai Jan 2015

Control Of Oxygen Excess Ratio In A Pem Fuel Cell System Using High-Order Sliding-Mode Controller And Observer, Seyed Mehdi Rakhtala, Abolfazl Ranjbar Noei, Reza Ghaderi, Elio Usai

Turkish Journal of Electrical Engineering and Computer Sciences

The main objective of this manuscript is to design a high-order sliding-mode observer to provide finite time estimation of unmeasurable states (x_4: oxygen mass, x_5: nitrogen mass) together with the oxygen excess ratio (ratio of the input oxygen flow to the reacted oxygen flow in the cathode). This is done by applying second-order sliding modes through either super twisting or suboptimal controllers to control the proton exchange membrane fuel cell's breathing. The estimated oxygen excess ratio is controlled in a closed-loop system using 2 distinct sliding-mode approaches: a cascaded super twisting controller and a single-loop suboptimal structure. Simulation results are …

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A Robust Algorithm Based On A Failure-Sensitive Matrix For Fault Diagnosis Of Power Systems: An Application On Power Transformers, Yunus Bi̇çen, Faruk Aras Jan 2015

A Robust Algorithm Based On A Failure-Sensitive Matrix For Fault Diagnosis Of Power Systems: An Application On Power Transformers, Yunus Bi̇çen, Faruk Aras

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a robust algorithm for fault diagnosis of power system equipment based on a failure-sensitive matrix (FSM) is presented. The FSM is a dynamic matrix structure updated by multiple measurements (online) and test results (offline) on the systems. The algorithm uses many different artificial intelligence and expert system methods for adaptively detecting the location of faults, emerging failures, and causes of failures. In this algorithm, all data obtained from the power transformer, which have various nonlinear input and output parameters, are processed using the parallel matrix structure of the FSM to reach a global solution quickly. The parameters …

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Enhancing Sliding Mode Control With Proportional Feedback And Feedforward: An Experimental Investigation On Speed Sensorless Control Of Pm Dc Motor Drives, Mehmet Dal Jan 2015

Enhancing Sliding Mode Control With Proportional Feedback And Feedforward: An Experimental Investigation On Speed Sensorless Control Of Pm Dc Motor Drives, Mehmet Dal

Turkish Journal of Electrical Engineering and Computer Sciences

This paper investigates the enhancement of sliding mode control (SMC) with the combined use of feedforward torque compensation and proportional error feedback control. The proposed enhancement is adapted to the control of permanent magnet (PM) DC motor drives by synthesis of the equivalent control equation augmented as proportional feedback and feedforward terms. A novel sliding function, introduced by utilizing the estimated load torque and the estimated rotor current, is examined and compared with another known sliding function obtained by nonideal differentiation of the estimated rotor speed. The significance of the proposed enhancements to SMC consists of the elimination of disturbance, …

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Mersenne Twister-Based Rfid Authentication Protocol, Mehmet Hi̇lal Özcanhan, Gökhan Dalkiliç Jan 2015

Mersenne Twister-Based Rfid Authentication Protocol, Mehmet Hi̇lal Özcanhan, Gökhan Dalkiliç

Turkish Journal of Electrical Engineering and Computer Sciences

This work presents an ultra-lightweight, cryptographic, mutual authentication protocol for radio-frequency identification (RFID) tags. The proposed scheme is more secure than its predecessors. The vulnerabilities of previous schemes based on triangular functions and rotation have been demonstrated in traditional and rotational cryptanalysis. In this paper, we summarize the successful attacks on previous schemes and demonstrate further attacks on 3 recent ultra-lightweight protocols. Next, we present a proposal that resists all of the known passive attacks. The proposal obeys the properties and rules of addition-rotation-XOR with constants systems. The proposed scheme inserts parts of advanced encryption standard S-boxes into the temperings …

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Dynamic Modeling Of Modular Fuel Cell For Maximum Power Point Tracking And Torque Ripple Reduction In Direct Torque Control Of Induction Motor, Majid Valizadeh, Mohammad Reza Feyzi, Ebrahim Babaei, Mehran Sabahi Jan 2015

Dynamic Modeling Of Modular Fuel Cell For Maximum Power Point Tracking And Torque Ripple Reduction In Direct Torque Control Of Induction Motor, Majid Valizadeh, Mohammad Reza Feyzi, Ebrahim Babaei, Mehran Sabahi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a comprehensive dynamic model of a proton exchange membrane fuel cell (FC) based on the electrical empirical model. The presented model is useful for online control as well as having suitable accuracy. FC stacks produce a DC voltage with a ratio of 2:1 in output from no-load to full-load. In vehicles that are equipped with FCs, the output voltage of the FC is drastically changed because the power and torque of the vehicle change with the driving cycle. In order to improve the performance of the direct torque control of induction motors, the modular structure of a …

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A New Heuristic Method To Solve Unit Commitment By Using A Time-Variant Acceleration Coefficients Particle Swarm Optimization Algorithm, Arsalan Najafi, Mohsen Farshad, Hamid Falaghi Jan 2015

A New Heuristic Method To Solve Unit Commitment By Using A Time-Variant Acceleration Coefficients Particle Swarm Optimization Algorithm, Arsalan Najafi, Mohsen Farshad, Hamid Falaghi

Turkish Journal of Electrical Engineering and Computer Sciences

Unit commitment is one of the most important problems in power system operation. Because of the large amount of parameters and constraints, it contains a high level of complexity. In this paper a new method based on a time-variant acceleration coefficients particle swarm optimization algorithm has been proposed to solve the unit commitment problem. Integer coding (for satisfying minimum up/down constraints) and binary coding (for satisfying spinning reserve constraint) have been utilized in the proposed method. Simulations in the different cases have been done with different sizes. Numerical results have shown the superiority and better convergence of the proposed method …

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Bandwidth Extension Of Narrowband Speech In Log Spectra Domain Using Neural Network, Sara Pourmohammadi, Mansour Vali, Mohsen Ghadyani Jan 2015

Bandwidth Extension Of Narrowband Speech In Log Spectra Domain Using Neural Network, Sara Pourmohammadi, Mansour Vali, Mohsen Ghadyani

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, there have been significant advances in communication technology, but speech signals still suffer from low perceived quality caused by bandwidth limitations of telephone networks. The bandwidth extension (BWE) approach adds high-frequency components of the speech signal to band-limited telephone speech and increases speech perception significantly. In this work, we develop a new method for representation of vocal tract filter coefficients using log of filter bank energy (LFBE) parameters as an alternative for mel-frequency cepstral coefficients (MFCCs). This approach is based on a strong correlation between the spectral components of low- and high-band spectrums. Furthermore, the performances of …

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Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan Jan 2015

Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan

Turkish Journal of Electrical Engineering and Computer Sciences

The channel allocation problem in cellular radio systems is NP-complete, and thus its general solution is not known for even the 2-channel case. It is well known that the link gain system matrix (or received-signal power system matrix) of the radio network is (and may be highly) asymmetric, and that as the Hopfield neural network is applied to optimization problems, its weight matrix should be symmetric. The main contribution of this paper is as follows: turning the channel allocation problem into a maxCut graph partitioning problem, we propose a simple and effective continuous-time Hopfield neural network-based solution by determining its …

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Improving The Performance Of Primal--Dual Interior-Point Method In Inverse Conductivity Problems, Ashkan Javaherian, Amir Movafeghi, Reza Faghihi, Effat Yahaghi Jan 2015

Improving The Performance Of Primal--Dual Interior-Point Method In Inverse Conductivity Problems, Ashkan Javaherian, Amir Movafeghi, Reza Faghihi, Effat Yahaghi

Turkish Journal of Electrical Engineering and Computer Sciences

This study improves the performance of primal--dual interior-point method in inverse conductivity problems via replacing the conventional, complicatedly calculated scalar regularization parameter with a diagonal matrix termed ``multi-regularization parameter matrix'' here. The solution of the PD--IPM depends considerably on the choice of the regularization parameter. Calculation of the optimal regularization parameter, which yields the most accurate solution, is not simple due to the long iterative nature of the algorithm. The objective optimization, which is implemented by minimizing error in the solutions over an extensive range of the regularization parameters, yields the most accurate solution that can be achieved, although this …

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A Particle Swarm Optimization-Based Approach To Achieve Optimal Design And Operation Strategy Of Standalone Hybrid Energy Systems, Mahram Ghazvini, Ali Abbaspour Tehrani Fard, Mahmud Fotuhi Firuzabad Jan 2015

A Particle Swarm Optimization-Based Approach To Achieve Optimal Design And Operation Strategy Of Standalone Hybrid Energy Systems, Mahram Ghazvini, Ali Abbaspour Tehrani Fard, Mahmud Fotuhi Firuzabad

Turkish Journal of Electrical Engineering and Computer Sciences

As a cost-effective and reliable alternative to supply remote areas, standalone hybrid energy systems (HESs) are recently under investigation to address various concerns associated with technical, financial, and environmental issues. This paper presents a comprehensive algorithm that can simultaneously optimize the component size, operation strategy, and slope of the photovoltaic panels of a standalone HES using an improved variant of particle swarm optimization (PSO), designated as the passive congregation PSO. A new operation strategy is proposed based on the set points of the control system. The optimization algorithm determines the optimal values of the set points to efficiently optimize the …

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