فصلنامه روشهای هوشمند در صنعت برق
پیاپی 6 (تابستان 1390)

In this article the performance of a DSTATCOM as an efficient parallel compensator، for obtaining the power indexes has been considered، Then، to improve the performance of DSTATVOM، each of its PI controller has been substituted by a nonlinear fuzzy-neural controller، based on trial error and derivation of system error. The cause of detorioration of power quality and the method of their compensation، in a distribution network، has been analysed، using Matlab. The simulation results show that، using the fuzzy-neural controller in place of linear controller in DSTATCOM controller، the ability of compensation in the active and reactive power voltage sag، swell and fliker، and reduction of low current and voltage harmonics has been improved cansiderably.

Matrix Converter (MC) is a direct energy conversion device with high input power factor. As a device without dc link elements، its output characteristic and reliability can be degraded by ac line side disturbances. This has attracted many researchers to make efforts to solve this problem. In this paper، under unbalanced input voltage conditions، behaviors of the MC controlled with Venturini method are analyzed. The output voltage is estimated and a PI controller compensation method to prevent negative effects of the input voltage harmonics is proposed. Using this technique، output harmonic contents are reduced and stable control of the load voltages and currents is ensured. The MC is used for fed induction motor that reference voltage for converter is computed with controller based on input-output feed-back linearization. Simulation results are presented in the paper to verify effectiveness of the approach.

A novel two-objective optimization design model for pulsed power supply (PPS) is proposed in this paper. The objectives are the muzzle velocity and the stored-to-kinetic energy efficiency. The design variables include the operating voltage and the trigger delay times between segments. The acceleration of the armature is constrained to lower than 106 m/s2. The optimization results for nuzzle velocity and the efficiency separately show the following: 1) The acceleration constraint has great influence on the performance; 2) wide current pulse yields high velocity but low efficiency; and 3) The operating voltage has to be increased to accelerate a heavier projectile to a certain velocity or at a certain efficiency. Pareto solution fronts for various projectile masses are found using the nondominated sorting genetic algorithm (NSGA-II) under the integration environment of MATLAB software.

Nowadays، the use of magnetic levitation systems has made attention in transportation. Suspension is caused by two magnetic fields in the near distance and thus the repulsion and attraction induced between them. In Iran، different types of magnetic systems and their applications، especially in the transportation system were not considered deeply and the features and specifications of each of these systems is not discussed yet. In this article we want to review past research and studies on the applications and the characteristics of these systems to fully express and we do compare them with each other. We also offer the laboratory equipment for study the behavior of magnetic suspension systems with emphasis on electrodynamic suspension.

Age-Related Macular Degeneration (AMD) is the second disease diabetes which causes blindness in aged people. The only remedy for AMD is intravenous injection of bavecizumab. To prove the efficiency of remedy، the degenerated cells in Macula should be measured. In this article، a modern system is introduced to measure Auto-Fluorescence in Macula part of retina in order to obtain number of degenerated cells. The system consists of three main parts: Pre-processing stage is omission of margins and reversion of images in retina. Analysis stage is in charge of classification of images and elicitation of their features. In classification the target areas are identified by methods like morphology، dynamic threshold and connected comportments and the features of target area including Euclidean distance to the center of image and density. In the stage of understanding by gathering the features of each class، we will get the measurable parameter of evaluating Auto Fluorescence by the help of which we can count the number of degenerated cells of Macula area. The results are coming from statistical analysis، including linear regression and correlation of data. Experiments have been done on a database of 34 retina images of AMD patients. The average statistical error rate is equal to76 percent. In clinical reviews، the founded relation to disinflation of Macula has been proved، while there were no proved relations to the vision decreasing or increasing of patients.

In this paper a new automatic approach to road extraction from aerial images is proposed. The initialization strategies are based on the intensity, color, and Hough transform. After road elements extraction, chain codes are calculated. In the last step, using shadow, cars on the roads are detected. We implemented our method on the 25 images from "Google Earth" database. The experiments show an increase in both the completeness and the quality indexes for the extracted road.

Multimode contour integral method is one of methods in analysis and design of H-plane waveguide circuits. In this method, the effect of higher order modes excited by discontinuities in waveguide structure is considered. This causes to approve the accuracy of method in analysis or design of complex waveguide circuits. In this article, the multimode contour integral method is used to determine the properties of dielectric resonators (DRs) such as resonant frequency and dielectric constant. Thus, it is not necessary to optimize or tuning the designed DR filter. Also the accuracy goes high. The accuracy of method is validated by comparison of results with those reported in literatures.

The Application of elliptic shaped ridge waveguide is presented for excitation of a centreline longitudinal shunt slot antenna. The proposed method is realized by adding elliptic shaped to the ridge of the single ridge waveguide. The elliptic shaped ridge is placed exactly under the longitudinal slot and the slot placed along centreline of the waveguide. It is shown that for a typical slot، the slot normalized conductance can be increased by increasing the elliptic shaped depth. The simulation results show that the proposed structure can be considered as a proper candidate for replacing the conventional longitudinal shunt slot.