Amirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401Optimal Design of Single-Phase Induction Motor Using MPSO and FEMOptimal Design of Single-Phase Induction Motor Using MPSO and FEM1943510.22060/eej.2014.435ENB.FarhadiMSc. Student, Department of Electrical Engineering, Faculty of Engineering, University of Guilan, Rasht, IranS.H.ShahalamiAssistant Professor, Department of Electrical Engineering, Faculty of Engineering, University of Guilan, Rasht, IranE.Fallah ChoolabiAssistant Professor, Department of Electrical Engineering, Faculty of Engineering, University of Guilan, Rasht, IranJournal Article20151006In this paper, a new approach is proposed for the optimum design of single-phase induction motor. By using the classical design equations and the evolutionary algorithms such as Genetic Algorithms (GA), Particle Swarm Optimization (PSO) and Modified Particle Swarm Optimization (MPSO), a Single Phase Induction Motor (SPIM) was designed with the maximum efficiency. The Finite Element Method (FEM) was used to achieve an accurate model of the motor. This model was used to validate the optimum design instead of implementing it practically that would be expensive. Results show that the efficiency of the motor designed by MPSO is higher compared to the ones designed by other methods. So this algorithm can be proposed as an appropriate tool in design of single-phase induction motors.https://eej.aut.ac.ir/article_435_ddb30680a691d157187ee1cf9e896d03.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401Cogging Torque Reduction in PMSM Motor by Using Proposed New Auxiliary WindingCogging Torque Reduction in PMSM Motor by Using Proposed New Auxiliary Winding111743610.22060/eej.2014.436ENK.AbbaszadehAssociate Professor, Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran, IranS.MaroufianMSc. Student, Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran, IranJournal Article20151006Performing fast and accurate methods for modeling the electrical machines has been the subject of several studies and many authors proposed different procedures to attain this aim. Beside the accuracy, the speed of the method is of great concern. On the other hand, the capability of the method to be changed according to the need is another important issue. Finite Element method provides relatively accurate results but it is time consuming and changing the parameters, once the model designed is difficult to be done. Magnetic Equivalent Circuit method is rather a new concept to model the electrical machines. The most important feature of the method is its flexible accuracy which can be determined due to the user's desire. Another important characteristic is the capability of the method in changing parameters. In this paper, a permanent magnet synchronous motor is modeled using Magnetic Equivalent Circuit; the values of the magnetic flux density and magnetic field intensity are calculated. Afterward, the generated output torque is calculated using Maxwell Stress Tensor. The comparison between the results of the MEC model and the Finite Element Analysis reveals the sufficient accuracy of the proposed method. Finally, a new method is proposed for cogging torque minimization which is based on the torque pulsation originated from an auxiliary winding. The result shows a significant reduction in the amplitude of the cogging torque.https://eej.aut.ac.ir/article_436_2421fcb1263b9530df88f7f002e78ea5.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401A New Guideline for the Allocation of Multipoles in the Multiple Multipole Method for Two Dimensional Scattering from DielectricsA New Guideline for the Allocation of Multipoles in the Multiple Multipole Method for Two Dimensional Scattering from Dielectrics192643710.22060/eej.2014.437ENM.RabbaniPhD. Student, Electrical Engineering Department, Amirkabir University of Technology, Tehran, IranA.TavakoliProfessor, Radio Communications Center of Excellence, Electrical Engineering Department, Amirkabir University of Technology, Tehran, IranJournal Article20151006A new guideline for proper allocation of multipoles in the multiple multipole method (MMP) is proposed. In an ‘a posteriori’ approach, subspace fitting (SSF) is used to find the best location of multipole expansions for the two dimensional dielectric scattering problem. It is shown that the best location of multipole expansions (regarding their global approximating power) coincides with the medial axis of the object. The subspace analysis is performed for various scenarios including objects with different shapes and sizes relative to the wavelength, different permittivities and both TE<sub>z</sub> and TM<sub>z</sub> polarizations. Numerical examples for both TE<sub>z</sub> and TM<sub>z</sub> cases are also presented. The results are in a very good agreement with the finite element method (FEM) results. Two challenging test cases are presented. First, a large object compared to the wavelength and second, a small object with field singularities close to the boundary. Accuracy of the final MMP results shows the effectiveness of the new allocation rule.https://eej.aut.ac.ir/article_437_fccb60fb512d13df5083790d64c4d5dd.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401Game-Based Cryptanalysis of a Lightweight CRC-Based Authentication Protocol for EPC TagsGame-Based Cryptanalysis of a Lightweight CRC-Based Authentication Protocol for EPC Tags273643810.22060/eej.2014.438ENK.BagheryMSc Student, Department of Electrical Engineering, Shahed University, Tehran, IranB.AbdolmalekiMSc Student, Department of Electrical Engineering, Shahed University, Tehran, IranM. J.EmadiAssistant Professor, Department of Electrical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20151006The term "Internet of Things (IoT)" expresses a huge network of smart and connected objects which can interact with other devices without our interposition. Radio frequency identification (RFID) is a great technology and an interesting candidate to provide communications for IoT networks, but numerous security and privacy issues need to be considered. In this paper, we analyze the security and the privacy of a new RFID authentication protocol proposed by <em>Shi et al.</em> in 2014. We prove that although <em>Shi et al.</em> have tried to present a secure and untraceable authentication protocol, their protocol still suffers from several security and privacy weaknesses which make it vulnerable to various security and privacy attacks. We present our privacy analysis based on a well-known formal privacy model which is presented by <em>Ouafi</em> and <em>Phan</em> in 2008. Moreover, to stop such attacks on the protocol and increase the performance of <em>Shi et al.</em>’s scheme, we present some modifications and propound an improved version of the protocol. Finally, the security and the privacy of the proposed protocol were analyzed against various attacks. https://eej.aut.ac.ir/article_438_1651cf0d2f737d7adeab84d339dbabd3.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401IIR System Identification Using Improved Harmony Search Algorithm with ChaosIIR System Identification Using Improved Harmony Search Algorithm with Chaos374743910.22060/eej.2014.439ENM.ShafaatiMSc. Student, Electrical Engineering Department, Faculty of Engineering, University of Guilan, Rasht, IranH.MojallaliAssistant Professor, Electrical Engineering Department, Faculty of Engineering, University of Guilan, Rasht, IranJournal Article20151006Due to the fact that the error surface of adaptive infinite impulse response (IIR) systems is generally nonlinear and multimodal, the conventional derivative based techniques fail when used in adaptive identification of such systems. In this case, global optimization techniques are required in order to avoid the local minima. Harmony search (HS), a musical inspired metaheuristic, is a recently introduced population based algorithm that has been successfully applied to global optimization problems. In the present paper, the system identification problem of IIR models is formulated as a nonlinear optimization problem and then an improved version of harmony search incorporating chaotic search (CIHS), is introduced to solve the identification problem of four benchmark IIR systems. Furthermore, the performance of the proposed methodology is compared with HS and two well-known meta-heuristic algorithms, genetic algorithm (GA) and particle swarm optimization (PSO) and a modified version of PSO called PSOW. The results demonstrate that the proposed method has the superior performance over the other above mentioned algorithms in terms of convergence speed and accuracy.https://eej.aut.ac.ir/article_439_eed5af6add95a9a6f1252739b1ad8c24.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401Design and Efficient Analysis of Large Reflectarray AntennaDesign and Efficient Analysis of Large Reflectarray Antenna495844010.22060/eej.2014.440ENI.AryanianPhD. Student, Department of Electrical Engineering, Amirkabir University of Technology, Tehran, IranA.AbdipourProfessor, Department of Electrical Engineering, Amirkabir University of Technology, Tehran, IranGh.MoradiAssistant Professor, Department of Electrical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20151006In recent years reflectarray antennas have received considerable attention due to their unique capabilities. However, due to their large size, analyzing the performance of these antennas using traditional full wave finite-difference and finite-element techniques requires considerable computational resources. In this paper, we present an efficient method to accurately analyze these class of antennas which considerably reduces the computational burden. First, the radiation properties of the unit cells of the antennas are obtained by applying periodic boundary conditions, which corresponds to an infinite array. Then, a phase-only algorithm is used to obtain required phase shift on the antenna surface. Next, different unit cells are used to achieve the required phase on the antenna surface. Lastly, to confirm the validity of our approach, each designed antenna is simulated by full wave method using method of moment and the full wave simulation results of co and cross polarization levels are compared with those obtained using the proposed formula. There is excellent agreement between the co- and cross polarization levels obtained by proposed approach and those obtained using full wave simulation.https://eej.aut.ac.ir/article_440_a8abb4bb284b5b27aa7cb790dc20f80b.pdfAmirkabir University of TechnologyAUT Journal of Electrical Engineering2588-291046120140401Indoor Positioning and Pre-processing of RSS MeasurementsIndoor Positioning and Pre-processing of RSS Measurements596644110.22060/eej.2014.441ENV.PourahmadiAssistant Professor, Electrical Engineering Department, Amirkabir University of Technology, Tehran, IranS.ValaeeProfessor, ECE department, University of Toronto, Toronto, CanadaJournal Article20151006Rapid expansions of new location-based services signify the need for finding accurate localization techniques for indoor environments. Among different techniques, RSS-based schemes and in particular one<br />of its variants which is based on Graph-based Semi-Supervised Learning (G-SSL) are widely-used approaches The superiority of this scheme is that it has low setup/training cost and at the same time it leads to low localization error. Analyzing the G-SSL method we can observe that its performance is highly dependent on its inputs (RSS measurements). The main objective of this work is to further improve the accuracy of G -SSL based schemes by performing multiple RSS measurements and then passing them through pre-processing blocks to improve the reliability of the corresponding RSS vector at each Sample Points (SPs). Experimental results are then followed to show the performance of the proposed method compared to what we get with the original G-SSL approach.https://eej.aut.ac.ir/article_441_15d4e891d784977cacbfcbb00c48f133.pdf