welcome

JECEI is devoted to the research in Electrical and Computer Engineering. The editors would like to welcome you to the Sixth issue (Vol. 3, No. 2), that contains six papers focusing on research works in Design and speed control of DC motor, Transmission congestion management, Axial flux permanent magnet synchronous motor, Objects identification, Radar cross section calculation, and CSA method for assigning client to servers. The article “Design and PLC Implementation for Speed Control of DC Motor Using Fuzzy Logic,”by J. Rostami Monfared et al., deals with designing a speed controller for a DC motor using fuzzy logic-based Programmable Logic Controller (PLC). The designed system contains three main parts including programmable logic controller, pulse width modulation bipolar drive and DC motor. In the control section, PLC is used as real time controller and Fuzzy logic algorithm is designed based on nonlinear model of DC motor, and its parameters are optimized in MATLAB software. Then, it is implemented using rslogix5000 PLC and programming language ladder for speed control. Finally, with favorable results, the efficacy of the controller is successfully proved under different load conditions. The next article, entitled “Transmission Congestion Management Considering Uncertainty of Demand Response Resources’ Participation,” by A. Tabandeh et al., presents an optimal model of Congestion Management (CM) by means of multi-state Demand Response Resources (DRRs), namely CM_DRR. In the proposed approach, in addition to DRRs, independent system operator relieves the existing transmission line congestions using the combination of generating unit rescheduling and involuntary load shedding. The hourly historical data associated with the Connecticut region in New England is employed to achieve the DRRs’ participation regime. Moreover, the impact of different capacities of DRRs on the congestion management cost and load shedding cost is evaluated. Applying the aforementioned model to the 24-bus Reliability Test System (RTS) indicates the efficacy of CM_DRR framework. In the third article, entitled “Optimal Design of Axial Flux Permanent Magnet Synchronous Motor for Electric Vehicle Applications Using GA and FEM,” by M. Ahmadi Darmani and H. Hooshyar, authors presents general design characteristics of Axial Flux Permanent Magnet (AFPM) machines. Moreover, torque density of the machine which is selected as main objective function, is enhanced by using Genetic Algorithm (GA) and variation of PM characteristics, based on sizing equation and Finite Element Analysis (FEA). Then, torque ripple of the motor is reduced according to the effect of PM characteristics on Torque Ripple Factor (TRF). The results are validated by using 3D-FEA . Furthermore, to assess the obtained results by FEA method, an advanced vehicle simulator (ADVISOR) software is used to demonstrate the performance improvement over the Europe test drive cycles. The article “Objects Identification in Object-Oriented Software Development - A Taxonomy and Survey on Techniques,” by H. Rashidi, has a literature review over techniques to identify objects and presents six taxonomies for them. The first taxonomy is based on the documents exist for a domain. The second taxonomy is based on reusable previous knowledge and the third one relies on commonalities in a domain. The fourth taxonomy is concerned with decomposing a domain. The fifth taxonomy is based on experience view and sixth one is related to use the abstraction in a domain. In addition, the constraints, strengths and weaknesses of the techniques in each taxonomy are described. Then, the techniques are evaluated in four systems inside an educational center in a university. A couple of approach is recommended for finding objects, based on some practical experiences obtained from the evaluation. In the fifth article, entitled “Modified Physical Optics Approximation for RCS Calculation of Electrically Large Objects with Coated Dielectric,” by H. Mohammadzadeh et al., ‎a new method for predicting the bistatic and monostatic Radar Cross Section (RCS) of coated electrically large objects is presented. ‎‎The proposed method uses modified Physical Optics (PO) approximation to obtain the object scattered field‎. ‎One of the advantages is the use of Stationary Phase Method (SPM) to solve the PO integral‎. By using SPM, the computation time required to solve this integral will be reduced compared to rigorously numerical integration techniques‎. Moreover, the simulation results are compared with commercial FEKO and CST software results in order to show its superiority as far as the computation time is concerned‎. Finally, in the sixtharticle, “A CSA Method for Assigning Client to Servers in Online Social Networks,” by S. Minaee Jalil and A. Khaleghi, authors proposes the use of a heuristic algorithm named Centralized Simulated Annealing (CSA) to get a good near optimum solution for the problem of user-server assignment in online social network systems. Simulation results of this investigation show that using a relatively small number of iterations, this approach achieves a very good performance improvement. On the other hand, the average number of iterations needed to achieve the near-optimal solution, will be slightly increased when the number of users in the network increase. The editors of JECEI wish to take this opportunity to thank the scientists and reviewers around the world who have contributed their time and expertise in the preparation of the sixthissue of the journal. The author is solely responsible for the validity of scientific material is written.