Electrical and Electronics

The QRS complex is the most striking waveform within the electrocardiogram (ECG). QRS provides the fundamentals for almost all automated ECG analysis algorithms. We proposed a novel method for classification of ECG beats using shared counters. We first developed a real-time QRS detection technique using two-phase hashing to extract precise QRS points. Then we implement a novel ECG beat classifier to profile each patient’s normal cardiac behavior. Our technique relies more on the data stream corresponding to ECG beats than any particular feature. We use the concept of shared counters to minimize the memory requirement. The algorithm automatically adjusts parameters periodically to adapt to ECG changes as QRS morphology and heart rate. Having such profile is essential for various diagnosis (e.g., arrhythmia) purposes. One application of such profiling scheme is to automatically raise an early warning flag for the abnormal cardiac behavior of any individual.

ZnO is introduced as an alternative to TiO2 in dye sensitized solar cells (DSSCs) due to its band gap similar to TiO2, higher electron mobility, and flexible procedures of preparations. Several samples of ZnO films are prepared with the hydrothermal synthesis method and the sol-gel technique, respectively. These ZnO films were assembled as photo anodes in DSSCs using N3 dye as the sensitizer. The performance of dye sensitized solar cells is mainly based on the dye as a sensitizer. Natural dyes have become a viable alternative to expensive and rare organic sensitizers because of its low cost, easy attainability, abundance in supply of raw materials and no environment threat. The nature of these pigments together with other parameters has resulted in varying performance. This review briefly discusses the emergence, operation and components of dye explained solar cells together with the work done on natural dye based dye sensitized solar cells over the years.

Continuous stirred tank reactor system is a typical chemical reactor system with complex non linear dynamic characteristics. There has been considerable interest in its state estimation and real time control based on mathematical modeling. However, the lack of understanding of the dynamics of the process, the highly sensitive and non linear behavior of the reactor, has made difficult to develop the precise mathematical modeling of the system. An efficient control of the product concentration in CSTR can be achieved only through accurate model. In this paper, attempts are made to alleviate the modeling difficulties using “Artificial Intelligence” (AI) techniques such as neural, fuzzy and neuro-fuzzy. Simulation results demonstrate the effectiveness of Artificial Intelligence modeling techniques. The performance comparison of different modeling techniques has been given in terms of root mean square error.

Photovoltaic (PV) Smart Grid systems can make a positive contribution to the sustainability of rural communities in developing countries that do not have access to electricity grid. Integration of solar photovoltaic system with diesel generator for remote and rural areas would assist in expanding the electricity access in the tropical region. The Smart Grid approach performance in terms of technical and economic aspects and their prospects has been presented in this paper.

Electricity power distribution networks are sometimes disturbed by a phenomenon known as ferroresonance. Causes, effects and remedies of ferroresonance are discussed in this paper. It is a nonlinear resonance in transformers which occurs during switching operations and lightning on networks containing inductors, capacitors and iron core materials that easily saturates. Overvoltages, overcurrents and distortions results’, causing overheating, damage to equipment, transformers and sometimes explodes. Difficult to predict, hence, in solving its problems, no mathematical solution is applicable yet. However, theoretical principles, simulations and measurements are commonly adopted. Secondary sources were used and the paper undoubtedly shall guide designers, manufacturers of transformers and operating personnel to ensure equipment longevity and safe operations for effective service delivery.

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.