Amirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101Active Filter Control Method Based on Direct Power Control for Compensating Reactive Powers due to Unbalanced Voltages and Nonlinear LoadsActive Filter Control Method Based on Direct Power Control for Compensating Reactive Powers due to Unbalanced Voltages and Nonlinear Loads1827910.22060/eej.2009.279ENE.AbiriiCorresponding Author, E. Abiri is with the Department of Electrical Engineering, Shiraz University of Technology (SUTECH), Shiraz, Iran (emil:
abiri@sutech.ac.ir)M.R.SalehiiiM. R. Salehi is with the Department of Electrical Engineering, Shiraz University of Technology (SUTECH), Shiraz, Iran (e-mil:
salehi@sutech.ac.ir)A.AbrishamifariiiA. Abrishamifar is with the Department of Electrical Engineering, Iran University of Science and Technology (IUST), Tehran, Iran, (email:
abrishamifar@iust.ac.ir)Journal Article20140317Active filters have proven to be more effective than passive techniques to improve power quality and to solve harmonic and power factor problems due to nonlinear loads. This paper proposes a control scheme based on the instantaneous active and reactive power. The inverter of this active filter is a three-phase, two-level converter. Space vector technique is used as modulators and pattern generators for the Pulse Width Modulated converter. Virtual Flux and a Phase Locked Loop based on a Double Synchronous Reference Frame cause this control system be resistant to the majority of line voltage disturbances. Good dynamic response, independent control of active and reactive powers and also unity power factor of converter are advantages of the proposed method. The operation of the proposed control strategy is verified in MATLAB simulation environmenthttps://eej.aut.ac.ir/article_279_4556dad4d653094fa8ba472bdf8a2dc2.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101ISAR Image Improvement Using STFT Kernel Width Optimization Based On Minimum Entropy CriterionISAR Image Improvement Using STFT Kernel Width Optimization Based On Minimum Entropy Criterion91628010.22060/eej.2009.280ENM.Modarres-HashemiM. Modarres-Hashemi is with the ECE Department of Isfahan University of Technology, Isfahan, Iran (email: modarres@cc.iut.ac.ir)M.DorostganM. Dorostgan is with the ECE Department of Isfahan University of Technology, Isfahan, Iran ( email:mdorostgan@alumni.iut.ac.ir)M. M.Naghshiii *Corresponding Author, M. M. Naghsh is with the ECE Department of Isfahan University of Technology, Isfahan, Iran
(email: mm_naghsh@ec.iut.ac.ir)Journal Article20140317Nowadays, Radar systems have many applications and radar imaging is one of the most important of these applications. Inverse Synthetic Aperture Radar (ISAR) is used to form an image from moving targets. Conventional methods use Fourier transform to retrieve Doppler information. However, because of maneuvering of the target, the Doppler spectrum becomes time-varying and the image is blurred. Joint Time-Frequency Transforms (JTFT) like Short-Time Fourier Transform (STFT) can resolve the Doppler spectrum and reduce the image blurring. These transforms use some kernels for signal spectrum analysis. According to the uncertainty principle, the proper selection of this kernel and its parameters could affect the quality of the image. In this paper, using a conventional kernel for STFT, i.e. Gaussian kernel, we use minimum entropy criterion to optimize the kernel duration. Simulation results show that this optimization can improve the constructed image compared with the Fourier transform method.https://eej.aut.ac.ir/article_280_d70481b09bf6bd2de0e7ced2b47b239a.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101A Solution to View Management to Build a Data WarehouseA Solution to View Management to Build a Data Warehouse172728110.22060/eej.2009.281ENN.DaneshpourCorresponding Author, N. Daneshpour is a PhD candidate of the Department of Computer Engineering & Information Technology, Amirkabir
University of Technology, Tehran, Iran (email: daneshpour@aut.ac.ir).A.Abdollahzadeh BarfouroshA. Abdollahzadeh Barfourosh is with the Department of Computer Engineering & Information Technology, Amirkabir University of
Technology, Tehran, Iran (e-mail: ahmad@ce.aut.ac.ir).Journal Article20140317Several techniques exist to select and materialize a proper set of data in a suitable structure that manage the queries submitted to the online analytical processing systems. These techniques are called view management techniques, which consist of three research areas: 1) view selection to materialize, 2) query processing and rewriting using the materialized views, and 3) maintaining materialized views. There are several parameters should be considered in order to find the most important algorithm for view management. As various researches have been done to propose view selection algorithms, we should select and modify the most suitable algorithm for view materialization based on the properties of the applications. In this paper, we investigate and find relevant parameters to view selection algorithms and classify them based on these parameters. We also present a system to evaluate algorithms and compare them with respect to the values of the evaluation parameters. Based on the results of these activities, we propose a roadmap that helps us choose the most efficient view selection algorithm concerning application types.https://eej.aut.ac.ir/article_281_921feaff71a8f4754313270d116e8bbf.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101A Quantitative Evaluation of Maintainability of Software Architecture StylesA Quantitative Evaluation of Maintainability of Software Architecture Styles293828210.22060/eej.2009.282ENG.R.ShahmohammadiiG.R. Shahmohammadi is Ph.D. of Computer Engineering, Tarbiat Modares University, Tehran, Iran (e-mail: Shahmohamadi@modares.ac.ir)S.JaliliCorresponding Author, S. Jalili is with the Department of Computer Engineering, Tarbiat Modares University, Tehran, Iran (e-mail:
Sjalili@modares.ac.ir)Journal Article20140317Proper decisions play a crucial role in any software architecture design process. An important decision of design stage is the selection of a suitable software architecture style. Lack of investigation on the quantitative impact of architecture styles on software quality attributes is the main problem in using such styles. Consequently, the use of architecture styles in designing is based on the intuition of software developers. The aim of this research is to quantify the impacts of architecture styles on software maintainability that is an expected quality of each software. In this study, architecture styles are quantified based on coupling, complexity and cohesion metrics and ranked by analytic hierarchy process from a maintainability viewpoint. Metrics validation confirms fitness of the metrics. Regarding the great impact of this decision on maintainability of software product, the presented parametric model provides a basis for sensible selection of architecture style.https://eej.aut.ac.ir/article_282_9deda979381c5e1442657f54acd72c5b.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101Voltage Coordination of FACTS Devices in Power Systems Using RL-Based Multi-Agent SystemsVoltage Coordination of FACTS Devices in Power Systems Using RL-Based Multi-Agent Systems394928310.22060/eej.2009.283ENM. R.TousiiCorresponding Author, M. R. Tousi is PhD student in Department of Electrical Engineering, Amirkabir University of Technology, Tehran, Iran
(e-mail: smr_tousi@yahoo.com).S. H.HosseinianiiS. H. Hosseininan is with the Department of Electrical Engineering, Amirkabir University of Technology, Tehran, Iran (e-mail:
Hosseininan@aut.ac.ir).Mohammad BMenhajiM. B. Menhaj is with the Department of Electrical Engineering, Amirkabir University of Technology, Tehran, Iran (e-mail: tmenhaj@ieee.org).Journal Article20140317This paper describes how multi-agent system technology can be used as the underpinning platform for voltage control in power systems. In this study, some FACTS (flexible AC transmission systems) devices are properly designed to coordinate their decisions and actions in order to provide a coordinated secondary voltage control mechanism based on multi-agent theory. Each device here is modeled as an agent being able to cooperate and communicate with other devices. In this system, individual autonomous agents and intelligent decision makers learn to perform optimal actions through proper interactions with their environments. The SARSA Q-learning, which is an on-policy algorithm in reinforcement learning (RL) is then used and tested successfully in voltage control problem. In this research, the Java Agent DEvelopment (JADE) platform is used to implement the agents and to simulate their communications. The power system is also fully implemented in Java. The proposed intelligent MA based method is finally applied to IEEE 39-buses New England power system. The results of simulation better highlight the merit of the method and its ability in coordinating FACTS devices for removing voltage disturbances. https://eej.aut.ac.ir/article_283_0ffd8c085e6339091e867e2b075f7662.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101A Modified Hybrid MoM-Modal Method for Shielding Effectiveness Evaluation of Rectangular Enclosures with Multiple AperturesA Modified Hybrid MoM-Modal Method for Shielding Effectiveness Evaluation of Rectangular Enclosures with Multiple Apertures515828410.22060/eej.2009.284ENV.RezaeiiV. Rezaei (e-mail: vrezaei@hotmail.com),*R.MoiniiCorresponding Author, R Moini (corresponding author to provide phone: +98-21-6646-6009, fax:
+98-21-6640-6469, e-mail: moini@aut.ac.ir)S. H. H.SadeghiiS. H. H. Sadeghi (e-mail: sadeghi@aut.ac.ir) are with the Electromagnetics Research Laboratory of
Amirkabir University of Technology, 424 Hafez Ave., Tehran 15914, Iran.F.RachdiiiF.Rachdi Electromagnetic Compatibility Laboratory, Swiss Federal Institute of Technology (EPFL), Lausanne, SwitzerlandJournal Article20140317A new hybrid modal-moment method is proposed to calculate fields penetrated through small apertures on rectangular metallic enclosures. First, the method of moments is used to numerically solve the governing electric field integral equation for the equivalent two-dimensional surface-current distributions on the surface of metallic enclosure including any number of rectangular apertures of arbitrary lay-out. The resultant exterior scattered fields are then used as the input to a testing procedure to obtain aperture field distributions in the modal expansion technique. These fields can be directly transferred to interior penetrated fields, using appropriate Green’s function of the cavity inside region. To validate the method proposed in this paper, the results of the proposed method are compared with the measurement results available in the literature and those obtained using the conventional modal-moment method for both single and double aperture enclosures.<span class="AbstractWCCMChar"> It is shown that </span>the proposed method offers a remarkable improvement in computation burden over the conventional method, especially for calculation of field penetration through much number of apertures typical to realistic measures in the discipline of electromagnetic compatibility.https://eej.aut.ac.ir/article_284_3ea4f1cc22f2ecf1a810fb8fceca3b2a.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101Modeling of Tactile Detection of an Artery in a Soft Tissue by Finite Element AnalysisModeling of Tactile Detection of an Artery in a Soft Tissue by Finite Element Analysis596328510.22060/eej.2009.285ENAliAbouei MehriziA. Abouei Mehrizi is with the Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
(email: abouei.ali@gmail.com).SiamakNajarianCorresponding Author, S. Najarian is with the Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
(email: najarian@aut.ac.ir).MajidMoiniiiiM. Moini is with Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
(email: moinim@hotmail.com)Journal Article20140317Nowadays, one of the main problems encountered in minimally invasive surgery and telesurgery is the detection of arteries in tissue. In this study, for the first time, tactile detection of an artery in tissue and distinguishing it from the tumor has been modeled by finite element method. In this modeling, three 2D models of tissue have been created: tissue, tissue including a tumor, and tissue including an artery. After solving three models with similar boundary conditions and loadings, first, the 2D tactile mappings and stress graphs for upper nodes of models, which have the role of transferring tactile data, have been explored. Comparing these results, if stress values of nodes are equal and constant, tissue is without tumor or artery. In addition, it was concluded that if stress graph includes a peak, the tissue has a tumor or an artery and that the stress graph of tissue including artery is time-dependent in comparison with the tissue including the tumor.https://eej.aut.ac.ir/article_285_74df718ecedc3c8144e1c1c53f9b35ba.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291041220091101Design of a Fuzzy Controller Chip with New Structure, Supporting Rational-Powered Membership FunctionsDesign of a Fuzzy Controller Chip with New Structure, Supporting Rational-Powered Membership Functions657128610.22060/eej.2009.286ENA.NaderiiCorresponding Author, A. Naderi is with the Department of Electronic Engineering, urmia University, Urmia, Iran (e-mail:
ali.n.1384@gmail.com).H.GhasemzadehiiH. Ghasemzadeh, A. Pourazar and M. Aliasghary are with the Department of Electronic Engineering, urmia University, Urmia, Iran (e-mail:
hadi.g.1384@gamil.com, pourazar.alireza@gmail.com, m.aliasghari@gmail.com ).A.PourazarH. Ghasemzadeh, A. Pourazar and M. Aliasghary are with the Department of Electronic Engineering, urmia University, Urmia, Iran (e-mail:
hadi.g.1384@gamil.com, pourazar.alireza@gmail.com, m.aliasghari@gmail.com ).M.AliasgharyiiH. Ghasemzadeh, A. Pourazar and M. Aliasghary are with the Department of Electronic Engineering, urmia University, Urmia, Iran (e-mail:
hadi.g.1384@gamil.com, pourazar.alireza@gmail.com, m.aliasghari@gmail.com ).Journal Article20140317In this paper, a new structure possessing the advantages of low-power consumption, less hardware and high-speed is proposed for fuzzy controller. The maximum output delay for general fuzzy logic controllers (FLC) is about 86 ns corresponding to 11.63 MFLIPS (fuzzy logic inference per second) while this amount of the delay in the designed fuzzy controller becomes 52ns that corresponds to 19.23 MFLIPS. This mixed analog/digital realization of the circuit makes the design programmable and extendable. The proposed controller supports Rational-Power Membership Functions with a resolution of 0.03125. Simulation results of the controller using HSPICE simulator level 49 in 0.35um in CMOS process technology (BSIM3v3) show an average power consumption of 4.38mW, and an RMS error of 1.26%. This controller can be used in many applications in which there is a need for a controller chip by correct programming with system experts. Meanwhile the whole area of the chip is 0.0775mm<sup>2</sup>.https://eej.aut.ac.ir/article_286_5c15364c5b353bf0683b2c3e5d5ce69b.pdf