JOURNAL OF IRANIAN ASSOCIATION OF ELECTRICAL AND ELECTRONICS ENGINEERS
Year:2008 | Volume:5 | Issue:1|Papers Count:8

Test automation is one of the major areas in software engineering. Test automation can reduce the high cost of software development and at the same time increases the reliability of the testing process. In this paper we present a novel specification based framework for automating test process based on use case scenarios. It receives software specification that defined with UML at design level and source code. One of major byproduct of our framework is test pattern which can be used for other purposes such as design verification.

Automatic correction of typos in the typed texts is one of the goals of research in artificial intelligence, data mining and natural language processing. Most of the existing methods are based on searching in dictionaries and determining the similarity of the dictionary entries and the given word. This paper presents the design, implementation, and evaluation of a Farsi typo correction system using the Hopfield and multilayer perception (MLP) neural networks. The results show that for learning a dictionary of 4 to 256 words of 4 to 6 characters, the correction accuracy of the Hopfield network is 55% to 100%and for the multilayer perception 80% to 100%. The hybrid network can achieve a correction accuracy of 80% to 100% for over 3000 words.

Channel coding is one of the techniques used for suppression of fading and channel noise effects. Most of the researches on channel codes have been focused on the codes which are defined on Galois fields. Since two decades ago, using channel codes defined on real and Complex fields has been considered for joint source channel coding in multimedia transmission; but most of the works have focused on block codes. In this paper, we consider real field convolutional codes. In this regard, we propose a Kalman based decoding technique and analyze the performance of real field convolutional codes and our proposed decoding technique under fading channel and in the presence of Quantization noise.

The increase in fossil fuel prices has resulted in growing utilization of renewable energy sources in power systems. Wind energy as an economical source of energy has experienced the fastest growth among other energy sources. Traditionally, renewable energy sources as a result of their random nature have not been considered in the process of generation expansion planning. The increase in fossil fuel prices and their scarcity in the near future necessitate incorporating wind power in generation expansion planning. This paper studies the utilization of wind power in generation planning considering reliability constraints. Simulation results show that even though wind energy may make a major contribution to generation capacity planning, reliability limitations hinder full utilization of potential wind power. Therefore, conventional generating units should still be taken into account in generation planning while satisfying system reliability criteria.

Appropriate design and usage of Unified Power Flow Controller (UPFC), which has the ability of controlling the busbar voltage levels and transmission line power flows simultaneously; provide a suitable conditions to enhance operation of restructured power systems. In this paper, a novel control method using four degrees of freedom is represented for hysteresis based UPFC as well as a straight forward control method for series branch control system. Finally, the simulation results of the UPFC proposed in the paper in PSCAD/EMTDC software illustrates improved stability and power quality indices i.e. less overshoots and settling times, in comparison with other methods reported before.

Conventional fault location methods using voltages and currents of one terminal are not applicable to multi-terminal transmission lines. So far some techniques have been presented to solve fault location problem for multi-terminal transmission lines. In these methods, lumped or distributed frequency domain models of transmission lines have been used. In multi-terminal lines, faulty section should be detected before fault location estimation. In this paper, a method based on time domain model of transmission line is presented to identify the faulty section and to determine the location of faults for three-terminal transmission lines. In the suggested method, samples of voltages and currents at all three terminals are used for calculating the location of the fault. The proposed algorithm is independent of fault resistance, insensitive to load current and fault inception angle. Furthermore, in the method neither any knowledge about source impedance nor the fault type classification is required. Filtering of dc and high frequency components of voltages and currents signals are not necessary. The simulation results, using EMTP/ATP and MATLAB software, confirm the accuracy and precision of the proposed method.

A dynamometer is used to determine the electromechanical characteristics of electrical machines. So dynamometers are used to optimize the producing process of electromotor. Dynamometers are equipped with variety of systems which are so expensive and need some mechanical equipment to couple with motors. Furthermore using of these mechanical couplings is a time consuming process. In this paper a new software based dynamometry is presented. In this method at first, all parameters of motor are identified and then the characteristics of motor are obtained by using dynamic and static simulation. Finally, comparisons between simulation and measurement results show good agreement and validate this method.