فهرست مطالب

  • Volume:8 Issue: 4, 2014
  • تاریخ انتشار: 1393/09/15
  • تعداد عناوین: 10
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  • Mehrshad Salmasi, Homayoun Mahdavi-Nasab Pages 1-7
    Active noise control (ANC) works on the principle of destructive interference between the primary disturbance field heard as undesired noise and secondary field which is generated from control actuators. In the simplest system, the disturbance field can be a simple sine wave, and the secondary field is the same sine wave but 180 degrees out of phase. This research presents an investigation on the use of different types of neural networks in active noise control. Performance of the multilayer perceptron (MLP), Elman and generalized regression neural networks (GRNN) in active cancellation of acoustic noise signals is investigated and compared in this paper. Acoustic noise signals are selected from a SPIB database. In order to compare the networks appropriately, similar structures and similar training and test samples are deduced for neural networks. The simulation results show that MLP, GRNN, and Elman neural networks present proper performance in active cancellation of acoustic noise. It is concluded that Elman and MLP neural networks have better performance than GRNN in noise attenuation. It is demonstrated that designed ANC system achieve good noise reduction in low frequencies.
  • Mahmood Seifouri, Saeed Olyaee, Moslem Dekamin Pages 9-15
    In this paper, we report a new design of As2Se3 chalcogenide glass photonic crystal fiber (PCF) with ultra-flattened dispersion at mid-infrared wavelength range. We have used the plane wave expansion method (PWE) for designing the structure of As2Se3 glass PCF at different wavelength windows. In the proposed structure with hole to hole spacing and, the negative dispersion is -1025 ps/nm/km at the wavelength of 1.55µm and also an ultra-flattened dispersion is achieved at the wavelength range of 3.5-18μm. Hence such PCFs have a high potential to be used as dispersion compensating fibers at 1.55µm wavelength in optical communication systems. The ultra-flattened dispersion at the wavelength range of 3.5-18μm can be employed to achieve high power supercontinuum generation. The nonlinear coefficient of the proposed PCF is at the wavelength of 1.55µm. Chalcogenide glasses are known to have both high transparency and nonlinearity in a wide range of infrared wavelengths compared to silica glasses.
  • Kadali Ravi Kumar, Sydulu Maheswarapu Pages 17-26
    This paper puts forward the implementation of Cubic lattice structured multiagent based PSO algorithm (CLSMAPSO) to obtain the optimal power flows by optimally placing TCSC devices. The Thyristor Controlled Series Capacitor (TCSC) is modeled using susceptance model with modifications in the Y bus of the Newton Raphson Algorithm. The constraints related to violation limits, minimization of line overload factor, and line loss are dealt using penalty factor approach. The new multi agent based cubic lattice structured PSO algorithm was considered for optimizing power flows while satisfying all the constraints mentioned above. This algorithm was tested on IEEE14, IEEE 30 and IEEE 57 bus systems to identify the suitable location, its reactance value and firing angle. The results obtained were quite encouraging and will be useful in electrical restructuring.
  • Zahra Moravej, Hossein Kiani Rad Pages 27-35
    This paper presents a new method for solving Substation Expansion Planning (SEP) problem using three basic algorithms in fuzzy clustering. Clustering algorithms are mainly associated with distance functions and measure dissimilarities of data set in different clusters. It is equivalent to measure similarities of data in a cluster. That is, a lot of varieties exist to find and create such arranged clusters. The proposed clustering algorithms are Hard C-Means (HCM), Fuzzy C-Means and Possibilistic C-Means. At first, each algorithm is introduced and the differences are characterized. Objective function and optimization procedure of each algorithm are described afterward. Proper evaluation was done by simulating each algorithm. On the other hand, one of the complex and difficult issues in power systems is to find an appropriate response for substation expansion planning. By inspiring from HCM clustering method and by adding some necessary constraints, a new method was developed for solving SEP problem.The proposed method was applied to a typical network and good results were obtained. The results showed that the proposed method was highly effective in dealing with large networks. One of the features of this method is the possibility of introducing the location of new substations during the substation expansion planning. The fast convergence, conformity of solution with engineering perspectives, consideration of real-world networks limitations as problem constraints and simplicity in applying to real networks are the other features of the proposed method.
  • Babak Yousefi-Jhangah, Saeed Abapour, Shahram Yousefi-Khangah Pages 37-45
    If determination of location and size of Distributed Generation (DG) are applied accurately, the DG’s ability will improve the network situation and reduce operation costs. In this paper, various market conditions are considered to maximize the benefit of DG’s presence and make a trade off among advantages of DG, network situation, and Distribution Company (DISCO) owners. To determine the optimal location and size of DG, two methods of the cost minimization and the nodal pricing are combined. In addition to evaluating the impact of parameters such as variation of energy price and load on objective function, effect of these parameters on location and size of DG is considered. To confirm the results, impact of loads which are dependent on voltage and variation of the power factor of the DG units is applied and then Effect of power factor on optimal location and size of DG is shown. A method is proposed for convergence of different results which is caused by different power factors. To observe long-term impact of the DG’s presence in the network, a load growth for five years is considered annually. Study is carried out on IEEE-30 bus test circuit.
  • Hajar Bagheri Tolabi, Mohd Hasan Ali Pages 47-57
    This paper presents a new method for optimal multi-objective reconfiguration of distribution system based on the novel Intelligent Water Drops (IWD) algorithm in order to mitigation of losses, improving the voltage profile and equalizing the feeder load balancing. The proposed method is validated at nominal load by implementing on a 33 bus test system. The obtained results prove the proposed technique is more accurate than other well known methods such as Genetic Algorithm, Particle Swarm Optimization, and Harmony Search algorithm meanwhile it has an efficient convergence property in compared with other intelligent search algorithms.
  • Alireza Tabrizizadeh, Fariba Bahrami, Mohammad Javad Yazdanpanah Pages 59-65
    In this paper a locomotion control system for bipedal robot is proposed to provide desirable walking on a terrain and skipping over a pitfall preventing the robot from falling in it.The proposed strategy is a combination of motion optimization based on particle swarm optimization algorithm and utilization of mode switching at a higher level controller.The model for biped robot is a compass gait model but the method presented is general and could be appropriatly extended and generalized for other complicated models.
  • Hamed Hosseinnia, Dariush Nazarpour, Masoud Rezaei Benam Pages 67-72
    The reason that cogeneration is being used more compared to separate heat and power is because it is more efficient. In this paper the goal is finding the optimized CHP system utility size and thermal storage considering reliability limits of boiler and grid connected bus. Loss of Load Expectation (LOLE) and Expected energy not supplied (EENS) are considered as two reliability indices to insure the security of operation. non-sequentional Monte carlo simulation method is introduced to the reliability assessment of CHP,and a normal distribution electrical load model is built to simulate the hourly electrical load.CHP model combined with a two-state reliability model is applied to monte carlo simulation method, and results show that the CHP reliability model works well with non-sequential monte carlo simulation. Non-Sequential Monte Carlo method is used to generate scenarios. Also in order to reduce computation time and due to the large number of scenarios, a scenario reduction technique is used. GAMS software is used for optimization object.
  • Mehdi Jalali, Saeed Abapour, Kazem Zare Pages 73-82
    In this paper, in order to efficient placement of Distributed Generation (DG) in distribution network, applying the Data Envelopment Analysis (DEA) ranking method is proposed. In this regard first an analytical method to find the optimal size of DG in the network is used to reach the lowest possible losses. Since the loss reduction of whole the network will not be complete criteria for selection the best location to install DG. hence, in this paper addition to the network loss reduction, benchmarks such as improvement of voltage profile, reduce the not supply energy value (as an index of reliability), reduce environmental pollution, and values of related to the purchase and installation costs of DG equipment in each busses for selecting the appropriate DG location, are considered. What encourages the use of DEA to determine the most effective location for DG placement, is that we will observe that the necessarily node which has the highest reduction in power losses cannot be considered suitable node for the installation of DG. The proposed method is implemented over the network of 33 buses and the results are presented. For the simulation results extraction GAMS software is used.
  • Ebrahim Shabanpoor, Hossein Emami, Seyed Ali Hashemi Pages 83-94
    Passive defense in appropriate location of base transceiver station in Tehran is the main subject of this article. According to the GSM network architecture and its components, BTS is the most vulnerable part of this network. Under investigating current circumstances of BSCs and BTSs in Tehran an optimization of the deployment of these stations are examined regardless of the passive defense and with considering this issue. In determining location of base transceiver stations in Tehran, according to different modes of sharing, a model is designed in which the number of stations is causatively reduced. In addition, temporary Base Transceiver Stations and their variants are presented. Finally, a comparison of the results of the previous researches and this study show the proposal plan is advanced in terms of beautifying the city, economical aspects and defensive schemes. RAN sharing is a kind of sharing in which operators share towers, antennas and Back Hall up to the connecting dots of telecommunication core of operators’ network. This sharing has a particular importance both in terms of reducing the number of base transceiver stations and also reducing operators'' costs.
    Keywords: Passive defense, BTS, Investigation on the location, sharing sites