Iranian Journal of Electrical and Electronic Engineering

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Microarray technology is a new and powerful tool for concurrent monitoring of large number of genes expressions. Each microarray experiment produces hundreds of images. Each digital image requires a large storage space. Hence, real-time processing of these images and transmission of them necessitates efficient and custom-made lossless compression schemes. In this paper, we offer a new architecture for lossless compression of microarray images. In this architecture, we have used a dedicated hardware for separation of foreground pixels from the background ones. By separating these pixels and using pipeline architecture, a higher lossless compression ratio has been achieved as compared to other existing methods

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Hunting is a flutter associated with the synchronous speed that gives rise to the gyro drifting errors and may cause objectionable time-displacement errors in video head wheel drives and other precision scanning systems. In this paper, dynamic characteristics of permanent Magnet hysteresis motors are presented and hunting is explained. New damping techniques have been developed using optimized eigenvalues calculation. They are calculated from LQR optimization method. In this damping method, a distinct reduction in hunting has been archived. Furthermore field oriented control result of motor is presented that have good effect on Hunting. Nearest agreement between simulated and measurement results shows the accuracy of motor model. Comparison between this paper results and other measured damping methods result are shown its success.

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This paper presents the effects of instrument transformers connection points on the measured impedance by distance relays in the presence of Flexible Alternating Current Transmission System (FACTS) devices with series connected branch. Distance relay tripping characteristic itself depends on the power system structural conditions, pre-fault operational conditions, and especially the ground fault resistance. The structural and controlling parameters of FACTS devices as well as the connection points of instrument transformers affect the ideal tripping characteristic of distance relay. This paper presents a general set of equations to evaluate the measured impedance at the relaying point for a general model of FACTS devices to consider different affecting parameters.

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From the optimization point of view, an optimum solution of the unit commitment problem with reliability constraints can be achieved when all constraints are simultaneously satisfied rather than sequentially or separately satisfying them. Therefore, the reliability constraints need to be appropriately formulated in terms of the conventional unit commitment variables. In this paper, the reliability-constrained unit commitment problem is formulated in a mixed-integer program format. Both the unit commitment risk and the response risk are taken into account as the probabilistic criteria of the operating reserve requirement. In addition to spinning reserve of generating units, interruptible load is also included as a part of operating reserve. The numerical studies using IEEE-RTS indicate the effectiveness of the proposed formulation. The obtained results are presented and the implementation issues are discussed. Two sensitivity analyses are also fulfilled to illustrate the effects of generating unit failure rates and interruption time of interruptible load.

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In this paper, we propose a new chaos-based communication scheme using the observers. The novelty lies in the masking procedure that is employed to hide the confidential information using the chaotic oscillator. We use a combination of the addition and inclusion methods to mask the information. The performance of two observers, the proportional observer (P-observer) and the proportional integral observer (PI-observer) is compared that are employed as receivers for the proposed communication scheme. We show that the P-observer is not suitable scheme since it imposes unpractical constraints on the messages to be transmitted. On the other hand, we show that the PI-observer is the better solution because it allows greater flexibility in choosing the gains of the observer and does not impose any unpractical restrictions on the message.

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In this paper, using the neural space mapping (NSM) concept, we present a SPICE-compatible modeling technique to modify the conventional MOSFET equations, to be suitable for ballistic carbon nanotube transistors (CNTTs). We used the NSM concept in order to correct conventional MOSFET equations so that they could be used for carbon nanotube transistors. To demonstrate the accuracy of our model, we have compared our results with those obtained by using open-source software known as FETToy. This comparison shows that the RMS errors in our calculated IDS, under various conditions, are smaller than the RMS errors in IDS values calculated by the existing analytical models published by others.

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This paper presents a new method called vespiary regular hexagonal (VRH) model in order to calculate parasitic capacitance between conductor wire filaments of one turn of coil (OTC) and between conductor wire filaments and liner and also total capacitance of one turn of the helix magneto flux cumulative generator (MCG) coil include single-layer conductor wire filaments in form of rectangular cross-section. In this paper, wire filaments of the coil are separated into many very small similar elementary cells. In this structure, an equilateral lozenge-shape basic cell (ELBC) with two trapezium-shape regions is considered between two adjacent conductor wire filaments in one turn of the generator coil. This method applies to calculate stray capacitance of one turn of the coil with multi conductor wire filaments (CWFs).

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This paper presents an approach to calculate the equivalent stray capacitance (SC) of n-turn of the helical flux compression generator (HFCG) coil with multi layer conductor wire filaments (MLCWF) in the form of rectangular cross-section. This approach is based on vespiary regular hexagonal (VRH) model. In this method, wire filaments of the generator coil are separated into many very small similar elementary cells. By the expanded explosion in the liner and move explosion to the end of the liner, the coil turns number will be reduced. So, the equivalent SC of the HFCG will increase. The results show that by progress of explosion and decrease of the turns’ number in the generator coil total capacitance of the generator increases until the explosion reaches to the second turn. When only one turn remains in the circuit, a decrease occurs in the total capacitance of the generator.

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In this paper, a novel design of all-solid photonic bandgap fiber with ultra-low confinement loss is proposed. The confinement loss is reduced remarkably by managing the number of rods rings, up-doping level, pitch value, and rods diameters. Moreover, the designed PCF shows ultra-flattened dispersion in L- and U-band. Furthermore, a new design, based on introducing of an extra ring of air holes on the outside of the all-solid bandgap structure, is then proposed and characterized. We demonstrate that it significantly reduces the fiber diameter to achieve negligible confinement loss. The validation of the proposed design is carried out by employing a two dimensional finite difference frequency domain with perfectly matched layers.

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Resolvers are widely used in electric driven systems especially in high precision servomechanisms. Both encapsulated and pancake resolvers suffer from a major drawback: static eccentricity (SE). This drawback causes a significant increase in resolver output position error (RPE) which could not be corrected electronically. To reduce RPE, this paper proposes a novel structure with axial flux. Proposed topology, design guidelines, optimization procedure and several key features to improve the sensitivity of axial flux resolver (AFR) against SE are studied. Furthermore, to minimize RPE an optimized design is attained. The machines are investigated in detail by using d-q model and 3D time stepping finite-element analysis. The results of theses two methods are compared and both prototype machines (proposed and optimized) are built. In order to evaluate proposed topologies, an experimental test setup is devised. Finally, the experimental results of the prototype machines verified the analysis results.

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This paper focuses on the tracking and synchronization problems of hyperchaotic systems based on active backstepping method. The method consists of a recursive approach that interlaces the choice of a Lyapunov function with the design of feedback control. First, a nonlinear recursive active backstepping control vector is designed to track any desired trajectory in hyperchaotic Wang system. Furthermore, this method is applied to achieve hyperchaos synchronization of two identical hyperchaotic Wang systems. Also, it is used to implement global asymptotic synchronization between hyperchaotic Wang system and hyperchaotic Rössler system. Numerical simulations have been employed to verify the effectiveness of the three designed active backstepping control vectors.

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Strategic bidding in joint energy and spinning reserve markets is a challenging task from the viewpoint of generation companies (GenCos). In this paper, the interaction between energy and spinning reserve markets is modeled considering a joint probability density function for the prices of these markets. Considering pay-as-bid pricing mechanism, the bidding problem is formulated and solved as a classic optimization problem. The results show that the contribution of a GenCo in each market strongly depends on its production cost and its level of risk-aversion. Furthermore, if reserve bid acceptance is considered subjected to winning in the energy market, it can affect the strategic bidding behavior.

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In this paper, the propagation of electromagnetic waves through an infinite slab of uni- or bi- axial chiral medium is analytically formulated for an arbitrary incidence using 4×4 matrix method. In this powerful method, a state vector differential equation is extracted whose solution is given in terms of a transition matrix relating the tangential components of electric and magnetic fields at the input and output planes of the uni- or bi- axial chiral layer. The formulas of the reflection and transmission are then derived. Also, the presented method is verified by some typical examples and the results are compared with the results obtained by the other available methods.

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In this paper, five conditions that have been proposed by Cobb and Shenoy are studied for nine different mappings from the Dempster-Shafer theory to the probability theory. After comparing these mappings, one of the considerable results indicates that none of the mappings satisfies the condition of invariance with respect to the marginalization process. In more details, the main reason for this defect is that the classic projection process in DST loses some probabilistic information. Therefore, as regards this subject, a solution is presented for solving this problem for two mappings: the pignistic probability and the normalized plausibility transformation.

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The aim of the relay coordination is that protection systems detect and isolate the faulted part as fast and selective as possible. On the other hand, in order to reduce the fault clearing time, distance protection relays are usually equipped with pilot protection schemes. Such schemes can be considered in the distance and directional overcurrent relays (D&DOCRs) coordination to achieve faster protection systems, while the selectivity is maintained. Therefore, in this paper, a new formulation is presented for the relay coordination problem considering pilot protection. In the proposed formulation, the selectivity constraints for the primary distance and backup overcurrent relays are defined based on the fault at the end of the transmission lines, rather than those at the end of the first zone of the primary distance relay. To solve this nonlinear optimization problem, a combination of genetic algorithm (GA) and linear programming (LP) is used as a hybrid genetic algorithm (HGA). The proposed approach is tested on an 8-bus and the IEEE 14-bus test systems. Simulation results indicate that considering the pilot protection in the D&DOCRS coordination, not only obtains feasible and effective solutions for the relay settings, but also reduces the overall operating time of the protection system.

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Microgrids is an new opportunity to reduce the total costs of power generation and supply the energy demands through small-scale power plants such as wind sources, photo voltaic panels, battery banks, fuel cells, etc. Like any power system in micro grid (MG), an unexpected faults or load shifting leads to frequency oscillations. Hence, this paper employs an adaptive fuzzy P-PID controller for frequency control of microgrid and a modified multi objective Chaotic Gravitational Search Algorithm (CGSA) in order to find out the optimal setting parameters of the proposed controller. To provide a robust controller design, two non-commensurable objective functions are formulated based on eigenvalues-domain and time-domain and multi objective CGSA algorithm is used to solve them. Moreover, a fuzzy decision method is applied to extract the best and optimal Pareto fronts. The proposed controller is carried out on a MG system under different loading conditions with wind turbine generators, photovoltaic system, flywheel energy, battery storages, diesel generator and electrolyzer. The simulation results revealed that the proposed controller is more stable in comparison with the classical and other types of fuzzy controller.

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This paper presents an online two-stage Q-learning based multi-agent (MA) controller for load frequency control (LFC) in an interconnected multi-area multi-source power system integrated with distributed energy resources (DERs). The proposed control strategy consists of two stages. The first stage is employed a PID controller which its parameters are designed using sine cosine optimization (SCO) algorithm and are fixed. The second one is a reinforcement learning (RL) based supplementary controller that has a flexible structure and improves the output of the first stage adaptively based on the system dynamical behavior. Due to the use of RL paradigm integrated with PID controller in this strategy, it is called RL-PID controller. The primary motivation for the integration of RL technique with PID controller is to make the existing local controllers in the industry compatible to reduce the control efforts and system costs. This novel control strategy combines the advantages of the PID controller with adaptive behavior of MA to achieve the desired level of robust performance under different kind of uncertainties caused by stochastically power generation of DERs, plant operational condition changes, and physical nonlinearities of the system. The suggested decentralized controller is composed of the autonomous intelligent agents, who learn the optimal control policy from interaction with the system. These agents update their knowledge about the system dynamics continuously to achieve a good frequency oscillation damping under various severe disturbances without any knowledge of them. It leads to an adaptive control structure to solve LFC problem in the multi-source power system with stochastic DERs. The results of RL-PID controller in comparison to the traditional PID and fuzzy-PID controllers is verified in a multi-area power system integrated with DERs through some performance indices.

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