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Open Access Article
1 - Design of Dual-band Impedance Matching Circuit Using T-shape Shunt Stub
Hadi Andalib Ali-Abadi Fatemeh Geran GharakhiliIn this paper, a new dual-band impedance matching circuit is presented by using a two-section microstrip transmission line and an open-circuit T-shape shunt stub. The governing analytical relations of the structure is first obtained based on transmission lines theory. T MoreIn this paper, a new dual-band impedance matching circuit is presented by using a two-section microstrip transmission line and an open-circuit T-shape shunt stub. The governing analytical relations of the structure is first obtained based on transmission lines theory. Then, by applying the matching conditions on the obtained relations, i.e. matching an arbitrary load impedance with source impedance of 50Ω at desired frequencies, nonlinear equations are generated, and solved simultaneously, meeting the electrical and physical specifications of all parts of the scheme. In order to evaluate the performance of the proposed circuit, the scheme is depicted and simulated using HFSS software. Simulation results show that the relative bandwidth of the first and the second band are 76% and 11.8%, respectively. In comparison to the previously- schemes in literature, our proposed circuit yields to a wider bandwidth and less occupied area. Manuscript profile -
Open Access Article
2 - A Comparative Study on Despeckling Techniques in Intravascular Ultrasound Images
Sima Navabian Fereshteh Yousefi Rizi Zahra Alizadeh SaniIntravascular ultrasound (IVUS) imaging is a diagnostic imaging technique for tomographic visualization of coronary arteries and studying atherosclerotic diseases. These medical images are generally corrupted by multiplicative speckle noise due to the interference of th MoreIntravascular ultrasound (IVUS) imaging is a diagnostic imaging technique for tomographic visualization of coronary arteries and studying atherosclerotic diseases. These medical images are generally corrupted by multiplicative speckle noise due to the interference of the signal with the backscattered echoes. Speckle noise is an inherent property of medical ultrasound imaging, and it generally tends to reduce the image quality; thus, removing noise from the original medical image is a challenging problem for diagnosis applications. Trying to reduce speckle assists experts for better understanding of some pathologies and diagnosis purposes. Recently, several techniques have been proposed for effective suppression of speckle noise in ultrasound B-Scan images. In this paper, we overview the denoising techniques in both spatial and transform domain, and propose a new despeckling method based on Shearlet transform and ant colony optimization. To quantify the performance improvements of the speckle noise reduction methods, various evaluation criteria in addition to the visual quality of the denoised images are used. Our results showed that in general Shearlet transform with three different types of threshold selection is faster and more efficient than other techniques. In the case of accurate estimation of the variance of noise, Shearlet transform based on ACO yields acceptable results in comparison with others methods. This technique can obtain a favorable signal-to-noise ratio and successfully improve the quality of images and preserve edges and curves as well. Manuscript profile -
Open Access Article
3 - Reactive Power Management in Micro Grid with Considering Power Generation Uncertainty and State Estimation
Mohammad Reza Forozan Nasab Javad OlamaeiOptimal reactive power dispatch problem in power systems has thrown a growing influence on secure and economic operation, nonlinear and multi- modal problems. Used methods in this issue can be divided into two categories: First, the classical methods like linear program MoreOptimal reactive power dispatch problem in power systems has thrown a growing influence on secure and economic operation, nonlinear and multi- modal problems. Used methods in this issue can be divided into two categories: First, the classical methods like linear programming (LP), nonlinear programing (NLP), quadratic programming (QP), interior point methods (IPM), Newton-bused methods, and the second, heuristic methods like genetic algorithm (GA), evolutionary programming (EP), and particle swarm optimization (PSO). In this paper, projected quasi-Newton method (PQN) is used as an optimal algorithm. This algorithm is applied on a 6-bus micro grid in medium voltage level. To make the problem more realistic, a wind turbine is put in one of the buses to consider uncertainty in power generation. Also two buses data are not available to add state estimation to the problem. For troubleshooting of power generation uncertainty, time series prediction model is used to predict wind speed. To overcome the problems of unavailability of some bases information, maximum likelihood weighted least squares estimation (MLWLSE) is used. Finally obtained information is used to optimize the reactive power in micro grid. Manuscript profile -
Open Access Article
4 - Actuator Failures and Sensor Bias Compensation by Combination of Model Reference Adaptive Control & Kalman Filter Theory
Hossein Rahmani Amoli Karim SalahshorThe actuator failure and sensor bias pose very important challenges in the aerospace industry. Why adaptive control is a good way to deal with these problems? The paper addresses the problem of actuator failures and sensor bias compensation using the combination ofa mod MoreThe actuator failure and sensor bias pose very important challenges in the aerospace industry. Why adaptive control is a good way to deal with these problems? The paper addresses the problem of actuator failures and sensor bias compensation using the combination ofa model reference adaptive control (MRAC) approach and Kalman filter (KF) for state tracking objective. To comply this condition, an enhanced MRAC method is introduced for state tracking based on state feedback configuration and a number of adaptation laws have been formulated to maintain the desired system performance. The Kalman filter is used to estimate the states despite sensor bias, providing excellent and reliable estimates. Simulation results demonstrate the effectiveness of the presented method to achieve good state tracking performances in spite of the presence of actuator failures and sensor bias. Manuscript profile -
Open Access Article
5 - A Robust Controller Design for Piezoelectric Positioning Stage with Bouc-Wen Hysteresis Compensator
Abbas Rasaienia Mina Asnaashari Mona HemmatiIn this paper, an inverse compensator based on the Bouc-Wen model is used to reduce the effect of hysteresis on a piezoelectric micro-actuator. This compensator is used as an open loop controller which partially eliminates the system hysteresis effect. In the last step, MoreIn this paper, an inverse compensator based on the Bouc-Wen model is used to reduce the effect of hysteresis on a piezoelectric micro-actuator. This compensator is used as an open loop controller which partially eliminates the system hysteresis effect. In the last step, in order to increase the reliability of the system and to achieve the desired goals, a H∞ robust controller is proposed in the presence of a compensator, to detect in the presence of modeling error and compensator error. At the end, simulation results are provided by MATLAB to demonstrate the effectiveness of the proposed control scheme. These results indicate that the proposed scheme provides a robust system performance and the tracking error reaches zero with acceptable accuracy. Manuscript profile -
Open Access Article
6 - A Novel Method Based on Support Vector Machines to Classify Bank Transactions
Melika Tojjari Razieh FarazkishImprovements in information technology have contributed to the development of the e-banking industry. Specifically, despite the reduction of bank charges, e-banking is one of the payment methods that, by employing it based on valid theory, can be successful in satisfyin MoreImprovements in information technology have contributed to the development of the e-banking industry. Specifically, despite the reduction of bank charges, e-banking is one of the payment methods that, by employing it based on valid theory, can be successful in satisfying customers due to the easiness of access to financial transactions at any time and place with minimum required tools. A mobile device imposes an increasing amount of time, energy and expense in comparison with face-to-face visits. In spite of many benefits this channel has for customers, there are security concerns for service providers and users in the banking sector. Consequently, in this inquiry, the focus is on the role of the support vector machine neural network in the classification of Mellat mobile transactions. To implement the intended procedure, after compiling the information in the preprocessing stage and purification and normalization of data, feature selection is done with the main component analysis algorithm. Then, in post-processing stage, the Neural Network supports the Mobile Banking classification as a safe but fake system. In order to compare the suggested method, we use Bayon floors and multilayer perceptron. The outcomes demonstrate that the support vector machine neural network can fulfill the classification of user’s mobile banking transaction with a mean square error of 0.216 and a precision of 94.6% of all data. Manuscript profile
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