فهرست مطالب

  • Volume:35 Issue:6, 2011
  • Transactions of Electrical Engineering
  • تاریخ انتشار: 1390/10/03
  • تعداد عناوین: 5
|
  • Hatam A. Sheikhi, M. A. Masnadi-Shirazi Page 75
    The idea of co-located Multiple-Input Multiple-Output (MIMO) radars is based ontransmission of orthogonal signals. In conventional co-located MIMO radars, usually a set oforthogonal code modulated pulses is transmitted. In this approach, finding orthogonal signals with a proper range side-lobe level is a problem. In this paper the approach of transmitting a set of proper pulse-trains is proposed. In the pulse-train signaling, pulse compression is achieved by the stepped frequency idea and so, the range side-lobes of the compressed codes are not a problem in the process of code selection anymore. To separate the received pulse trains, a new approach based on the Independent Component Analysis (ICA) is proposed. Compared to other presented approaches which use a set of filter banks, it is shown that the ICA-based approach is less sensitive to the Doppler effect and the orthogonality of signals. So, better beam-forming features and less error in Direction of Arrival (DOA) estimation is gained in this approach. According to this approach, an appropriate signal design method is presented, based on the separation performance of ICA algorithms. It is shown that independent random sequences are proper signals in this sense.
  • H. Noori, S. Saryazdi, H. Nezamabadi-Pour Page 95
    In this paper a new image inpainting scheme using bilateral filters is proposed. Since inthe digital image inpainting pixels’ values in a damaged region are unknown and are needed in calculation of weights according to the range filter of bilateral filters, in the proposed scheme we substitute the difference between two gray level values in the range filter by multiplication of two vectors: direction between two pixels and gradient direction of known pixel in the neighborhood of damaged pixels. The algorithm is iterative, fast and simple to implement. In addition, to achieve a better performance, the number of iterations is adaptively determined according to the region type (structural or textural) using the local variance. To evaluate the performance of the proposed method, several comparative experiments are performed. Experimental results confirm the effectiveness of the proposed algorithm.
  • M. Rajabi Mashhadi (Ms) Ghazizadeh, M. H. Javidi Page 109
    Primary frequency regulation, as an ancillary service, is usually supported bygeneration reserves. Modern generating units have special technical features; e.g. their governor operation mode can be selected, their ramp rate can be selected to be either normal or fast, etc. On the other hand, there are some technical constraints; e.g. some generating units cannot participate in primary frequency control at their capacity limits. In this paper, operational technical features and constraints of generating units are incorporated in a"simultaneous scheduling of energy and primary reserve" problem. To obtain the optimal scheduling, a heuristic iterative method based on genetic algorithm is proposed. The role of fast ramp rate and other capabilities and constraints on scheduling are investigated through simulation studies. Simulation results show that taking fast ramp rate of generating units into account not only reduces the total operation cost, but will also end up with a feasible solution, even in cases where previously proposed methods fail. Also, simulation results indicate that using fast ramp rate, results in the reduction of both the price of electricity and its volatility.
  • M. Rahmani, M. Rashidinejad Page 127
    An integrated technique for solving transmission network expansion planningconsidering the allocation of reactive power sources using an AC model is presented in this paper. Embedding reactive power management in TNEP is a challenging task since AC load flow may not converge in absence of proper reactive power allocation. Usually transmission expansion planning and reactive power planning are considered as two distinct problems, but in this paper both problems are investigated concurrently. These two problems can be integrated because there is an inherent interaction between transmission line capacity and reactive power sources. In power systems, transferring reactive power may engage line capacity which requires more new transmission lines, while allocating reactive power sources close to the load centers may prevent the addition of new transmission lines. On the other hand, if reactive power sources are not included, real power losses will increase considerably and thereby reduce transmission line capacities. The main objective of this study is to show that both active and reactive power planning can be handled simultaneously. This non-convex combinatorial optimization problem is solved here using a real genetic algorithm (RGA). Significant results through case studies of two test systems show the advantages of the proposed integrated network planning.
  • M. Shivaie (Ms) Sepasian, M. K. Sheikh-El-Eslami Page 141
    In this paper a new framework is presented for multi–objective TransmissionExpansion Planning (TEP). This framework is based on a multiple criteria decision making whose fundamental elements are REliability and MARKet (REMARK). Investment cost, congestion cost, Users'' Benefit (UB) and Expected Customer Interruption Cost (ECOST) are considered in the optimization as four objectives. The proposed model is a complicated non–linear mixed–integer optimization problem. A hybrid Genetic Algorithm (GA) and Quadratic Programming (QP) is used, followed by a Fuzzy Sets Theory (FST) to obtain the final optimal solution. The planning methodology has been demonstrated on the 6–machine 8–bus test system to show the feasibility and capabilities of the proposed algorithm. Also, in order to compare the historical expansion plan and the expansion plan developed by the proposed methodology, it was applied to the real life system of the northeastern part of Iranian national 400–kV transmission grid.