Electrical and Electronics

For a DFIG based wind energy system, the Rotor side converter (RSC) controls the torque and active/ reactive power of the generator while Grid side converter (GSC) controls the DC-link voltage and its AC-side reactive power. The stability of DC link capacitor voltage ensures that a nearly sinusoidal voltage is delivered by the GSC which is used as inverter. The present paper explores the important issues of maintaining the DC link capacitor Voltage value as close as possible to the nominal value of 1150 V and its Reactive Power value as close as possible to 0 Mvar under certain common types of faults.

In Wireless networks, the security of data and information has important role in digital communication and multimedia communication. Different types of encryption algorithms have an important role to provide the security to the wireless networks. Cryptography basically used for the data confidentiality and privacy by making indiscernible. Hence the original data cannot be interrupted by the unauthenticated user. The encryption techniques and different types of useful algorithms are used to provide the more security to the applications. In this paper the well- known method chaotic algorithm is used. Chaotic algorithm is used in real time secure image transmission systems. This algorithm is very popular method used in Research for encryption and decryption process. The combination of chaotic theory and cryptography has very important role in Information Security. In this communication, a new image encryption algorithm based on chaotic map is proposed for gray scale 2D image. In this proposed algorithm, the plain or original image is taken which has MXN dimension. Then Redistribute the pixel pair wise by deciding.

In this paper we describes and analyzes the Zone Routing Protocol (ZRP),which is a hybrid mobile ad-hoc protocol which fragments the network into overlapping routing zones, allowing for the use of independent protocols within and between the zones. ZRP performance better than other protocols ,but increase network load by use of useless control packets and decrease of network performance.

Image compression is a widely addressed researched area. Image compression is a key technology in transmission and storage of digital images because of vast data associated with them. Various types of compression methods are present in place. The performance analysis of various schemes to compress a True image in graphical user interface is discussed in this paper. True images can be compressed with the help of same scheme as grayscale images by applying them to each of the three color components. Experimental results demonstrate that the STW wavelet algorithm is more efficient for PSNR while EZW method provides the better compression ratio.

The ultimate goal of the deployment of any voice-centric application is to provide a natural way of human-machine interaction in end-to-end communication and majority of the voice-centric applications in today’s world are promising the same. In this scenario, it is essential to investigate the performance of Speech-Enabled IVR (SEIVR) under the effect of different narrowband codecs. In this paper, the performance of SEIVR has been analyzed by utilizing an ASR engine and speech codecs. SPHNIX-3 has been used as the ASR engine which is CMU’s ASR toolkit for speech recognition and executable files of various narrowband codec are generated with the help of source code and it is taken from standard organizations such as ITU-T, ETSI and ISO/IEC. The results of this paper are completely based on the speech data from TIMIT speech database. The major work done in this paper is to prove that the recognition accuracy of SEIVR increases when there is an increase in Gaussian mixture from Context-Independent (CI) to Context-Dependent (CD) under the influence of various narrow band codecs.

A multiband slotted and defected ground microstrip patch antenna which operates at more than one frequency has been designed. It effectively tunes at 3GHz, 5.5GHz and 7.8GHz with satisfactory return loss obtained at these resonant frequencies, which is -10.72dB, -13.38dB and -14.55dB respectively. Size of the antenna is going to be compact. The substrate FR4 epoxy (relative permittivity: 4.4) is used in the design of the antenna. Antenna design is proposed in different type of slots such as T-shaped and rectangular-shaped etc. slots in patch. This design can be used for wide range of Wireless applications. For the simulation HFSS is used.

This paper presents a multiple description coding method for HD image. The proposed method is bases on the SPIHT algorithm which provides high image compression ratio. The algorithm based on wavelet transforms and Wavelet-based compression provides multi-resolution hierarchical characteristics. This proposed method also uses poly phase sampling technique to generate multiple descriptions. The technique reduces the transmission error and memory required for storing HD images. The proposed method proved higher performances in terms of PSNR when compared to the standard SPIHT. The graph of PSNR versus BER is given in the experimental results.

This paper presents various types of interpolation techniques to obtain a high quality image The difference between the proposed algorithm and conventional algorithms (in estimation of missing pixel value) is that if standard deviation of image is used to calculate pixel value rather than the value of near most neighbor, the image gives the better result .. The proposed method demonstrated higher performances in terms of PSNR and SSIM when compared to the conventional interpolation algorithms mentioned.

In this paper we interest to how we can make a multiphysics model of IM, the FEM currently represents the state-of-the-art in the numerical magnetic field computation relating to electrical machines. FEM is a numerical method to solve the partial differential equations that expresses the physical quantities of interest, in this case thermal transfer and Maxwell’s equations. This approach is possible by using special simulation package frequently exploited bout in university and industry. A simple description of each one of this famous software is presented. In this moment, with the complicity of the problem, we made a decoupling between the thermal phenomena, electromagnetic and mechanics phenomena, in the first time we considers only the transient thermal and the other phenomena are in steady state, on the other hand in the second times the thermal behavior is ignored. FEM analysis is used for study state and transient mode, thermal transient, magnetic field calculation, the magnetic flux density and vector potential of machine is obtained. In this model we including, non linear material characteristics, eddy current effect, torque-speed characteristics, and magnetic analysis are investigated. Finally some simulation results of induction motor modeled by Motor-CAD and Maxwell software are given and commented.

Direct sequence code division multiple access (DS-CDMA) is a popular wireless technology. This system suffers from Multiple Access Interference (MAI) caused by Direct Sequence users and Near –far effect. Multi-User Detection schemes are used to detect the users’ data in presence of MAI and Near- far problem. In this dissertation, we present comparative study between linear multiuser detectors and conventional single user matched filter in DS-CDMA system. Analysis and simulations are conducted in synchronous AWGN channel, and Gold sequence and Kasami sequence are used as the spreading codes. Simulation results depict the performance of three detectors, conventional detector, Decorrelating detector and MMSE (Minimum Mean Square Error) detector. It shows that the performance of these detectors depends on the length of PN code used and Number of users. Linear multiuser detectors perform better than the conventional matched filter in terms of BER performance. All the simulations have been performed on MATLAB 7.0.