Electrical and Electronics

When solar cells are used for space applications, there are exposed to different types of energetic particles such as protons and electrons. Those energetic particles create defects in the base of the solar cell and lead to the degradation of the performances of the solar cell. Three mainly phenomenon observed in silicon solar cells exposed to 1 MeV electron irradiation are decrease in diffusion length, removal of majority charge careers and enlargement of Space Charge Region (SCR). These three phenomenon lead to the type conversion of the base of solar cell and an anomalous behavior of the short-circuit current for a certain value of the fluences. In the present study, theoretical approach is used to investigate the impact of decrease in diffusion length, removal of majority charge careers and enlargement of SCR on the anomalous behavior of the short-circuit current and type conversion of the base.The electric parameters are studied under AM 1.5 for different fluences of 1 MeV electrons.It was found that, defects responsible for the anomalous behavior of the short-circuit current could appear for different values of the fluences and that, the type conversion of the base is caused by the removal of the majority charged carriers and decrease in diffusion length while the anomaly observed in the evolution of the short-circuit current is caused by the widening of the SCR.

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 the present era real time security is of prime priority for any organization, corporate institutions, firms and various confederacy agencies. The idea is to design and develop an exhaustive real-time security system that will provide multifarious verification levels for enhanced security.The system uses a series of confirmation phases which includes identification, authentication, access granting and information updating and logging.In this project various components like microcontroller, Radio frequency Identification technology, GSM technology, and access control system will be integrated so as to achieve a real-time security system. This project is more secure than any other security system because the administrator will be provided with the logging information about the access moreover the passwords generated by the microcontroller will be random and hence cannot be tracked thus making the system not possible to hack

This paper presents the solution to the problem of grid voltage instability during occurrence of fault, on a system connected with wind turbine - driven doubly-fed induction generator (DFIG) which supplies alternating current (AC) power to the utility grid. Here, two pulse width modulated voltage source converters are connected back to back between the rotor terminals and utility grid via common direct current (DC) link. The grid side converter controls the power flow between the DC bus and the AC side. It allows the system to be operated in sub-synchronous and super synchronous mode of operation. The rotor excitation is provided by the machine side converter. The model makes use of d-q rotor reference frame using dynamic vector approach for machine model. The controller was implemented by the orientation of the generator stator flux vector along a synchronous reference axis. In this way, constant voltage and frequency was obtained and the generator would supply the active and reactive power demanded for the voltage correction by the load, while the wind turbine will be responsible for achieving power balance in the system. The system is modelled and simulated in the Matlab Simulink environment in such a way that it can be suited for modelling of all types of induction generator configurations. The results of the simulations show that DFIG wind turbines improved the voltage stability of the system through its ability to control reactive power and decouple control of active and reactive power by independently controlling the rotor excitation current especially during fault.

In the latest development of Orthogonal Frequency Division Multiplexing (OFDM) communication system, the system performance can be distracted by the frequency offsets (FOs) which can demolish the orthogonality of the subcarriers, and hence leads to a number of impairments in the received signal, thereby making its detection incorrect. In this paper, a new threshold-based frequency offset estimation algorithm for orthogonal frequency division multiplexing (OFDM) systems is proposed. Through a detailed analysis and simulation over AWGN channel, it has been shown that the proposed method shows good performance i.e. it offers low error variance as the SNR (signal to noise ratio) increases.

Fourth-Generation (4G) wireless networks will be heterogeneous, integrating different networks to provide continuous access for mobile users with multi mode access capability. The Fourth Generation communications systems is all about a global wireless communications system and defines a cost effective, simple, operable and personalized according to the users’ needs concept. The vertical handoff requirements are potential of the network, network cost, handoff latency, network conditions, power consumption and user’s preference. These must be considered during vertical handoff. In this research paper a new vertical handoff decision based on ARM & AI Techniques is designed. A refined, intelligent Associative Rule Mining (ARM) and Artificial Intelligence (AI) based technique is used to execute the vertical handoff intelligent mechanism in fourth generation wireless networks to produce an effective service which reduces the handoff delay and complexity.

This research describes a mammographic lesions using wavelet based active contour model. The sensitivity of the breast cancer detection was analyzed by mammography. Wavelet based decomposition techniques are used and tested for decomposing the noise present in the mammographic lesions. Gabor filtering method is used to reduce the unwanted noise obtained in the mammographic lesions by automated segmentation. The experimental results are tested with the MATLAB and proved reliable and cost effective.

Determination of optimum turning parameters in turning operations is one of the important tasks of process planners. The importance of this task is due to the fact that the values of turning parameters affect such objectives as turning time, turning cost and surface roughness. Thus, this problem is a multi-objective decision-making issue meaning that a parameter setting which satisfactorily achieves one of these objectives, it may not be good with respect to other objectives. Therefore, a rational compromise is to be made among these objectives. This paper determines the best cutting parameters considering relevant constraints in turning operations using a genetic algorithm coupled with an Analytic Hierarchy Process approach. The main stages of the proposed approach are two folds: (a) the non-dominated turning parameters being in the Pareto frontier are identified through a genetic algorithm, and (b) the AHP method is used to select the most suitable values for turning parameters from amongst the non-dominated solutions obtained in the first stage. Application of the proposed approach is demonstrated though an illustrative numerical example.

Regulation and controllability have been an important aspect of the industrial motor drives. The three-phase induction machine has been the motor of choice in industrial settings for about the past decade due to its easy speed and torque controllability. Its ruggedness and low cost cum other inherent features thus necessitated the quest to study its operating behavior. This work highlighted the mathematical modeling of an induction motor specifically in the stationary reference frame. The induction motor parameters and the generated equations were used to form the embedded MATLAB function which in turn was used to generate graphs that illustrate the performance of a 5HP motor. The torque –speed response among other characteristics were fully simulated thus resulting to a sound study of the performance characteristics of a three phase 5HP induction motor using MATLAB/Simulink.

As we know radium cutting through PC is readily available from that, we got the idea of our project i.e. "Low cost, thermocol cutter". In this project the microcontroller is the backbone of the hardware circuitry. All the controlling actions are done by the micro controller. A hot rod basically the soldering gun is used for cutting purpose. Here, the thermocol is not actually cut, but it is melted at a specified temperature with the help of soldering gun. So this project is used for cutting different figures and shapes as per the program of the micro controller. Optocouplers are used to provide isolation between the micro controller and the hardware circuitry. Stepper motors are used for controlling the different directions of different axis. Thickness of the thermocol will depend upon the length of the cutter and its heating capacity. Alphabets and numerical are generally cut using this project but figures of all shapes and sizes can be cut up to the limit of the work platform.