Electrical and Electronics

This paper proposed the Proportional Integral Derivative (PID) type multiple stabilizers to damp inter-area and intra-area low frequency oscillations in power system utility. To improve power system stability, optimal tuning of the PID type stabilizer gains and non-smooth nonlinear parameters is importance and a challenging task to accommodate variations in the power system dynamics, mainly when multiple PSSs are applied. Because, it is a computationally expensive combinational and nonlinear optimization problem. In this paper, Elitist Gravitational Search Algorithm (EGSA) is proposed to optimize multiple PID type PSSs gains tuning problem, simultaneously in order to reduce stabilizer design effort and find the best possible solution. The EGSA is a novel meta-heuristic stochastic optimization algorithm and simulates the masses cooperate using a direct form of communication through gravitational force to find the best possible solution within a reasonable computation time. It provides both global and local search by changing the velocities over time to determine distance and direction of agents (masses) for significant increasing the probability of finding the optimal solution and efficiently avoiding local optimum to a large extent. To optimize of multiple PSSs gains a nonlinear time domain-based objective function under various operating conditions is considered. It is solved using EGSA technique that has strong and robust search capability than the other heuristic optimization algorithm, as well as is being easy to implement. The effectiveness of the proposed EGSA based stabilizers is investigated on a two-area four machine power system through the nonlinear time domain simulation and some performance indices under different operation condition and system configurations. The performance of the proposed stabilizer is compared with those of standard Particle Swarm Optimization (PSO) and PSO with time variant acceleration coefficients based designed PSSs to illustrate its robustness and damping quality. The results analysis reveals that the EGSA based tuned PID type PSS is effective and achieves good low frequency oscillations damping capability. Moreover, it is superior that of the PSO method in terms of accuracy, convergence and computational effort.

Environmental friendly energy system is going to develop compared to convectional primary energy due to energy security problems. As the cost of solar energy is zero, the demand of solar energy is gradually increased in different purposes such as electricity, cooling and so on. Moreover, in the energy market, Photovoltaic (PV) inverters bear a very important role due to cost and efficiency. Hence, Transformer (TRX)-less inverter system is part and parcel where possible to reduce the overall system cost, size with high efficiency. In this review paper, different TRX-less inverter topologies are focused with the different switching conditions and the process of Leakage Current Reduction (LCR). Here is shown the basic concept of PV panel, flow chart according to the review papers, different leakage current paths and the mitigation processes.

The field of computer graphics is rapidly maturing to the point where human subjects have difficulty distinguishing photorealistic computer generated images (PRCG) from photographic images (PIM). In legal situations and in the intelligence community where photographs are used as evidence, it is crucial to understand whether the image is authentic or forged. So, it is very essential to develop the system which can distinguish between original images and computer generated images. Computer graphics many softwares are capable of generating highly photorealistic images that can be impossible to differentiate from photographic images. Therefore, classifying photographic images and photorealistic computer graphics has become an important problem for image forgery detection. So, we are providing the novel approach for this problem using Demosaicing algorithm. Demosaicing algorithm is having some special features. Missing color values are determined from a weighted linear combination of neighboring pixels. The process of demosaicing interpolates the raw image to produce at each pixel an estimate for each color channel. With proper analysis, traces of demosaicing are exhibited in the peak of an analysis signal. The presence of demosaicing indicates the image is from a digital camera rather than generated by a computer.

A circuit which accepts two sinusoidal waveforms with phase difference Ø and provides two dc output voltages in which one dc output voltage is proportional to the quadrature component SinØ and the another is proportional to the in phase component CosØ, by position sampling of the reference quadrature waveforms, is described in this letter.

Si-based resonant interband tunneling diodes (RITD) with spacer thicknesses varying from 2.5 to 25 nm was grown and fabricated at Baghdad University. The effect of spacer thickness on the peak-to-valley current ratio (PVCR), peak current density (JP), and voltage swing (VS) was studied for determining the static or dynamic read access memory (SRAM, DRAM). By increasing the tunneling spacer thickness up to 12 nm, RITDs with VS are reduced below 0.3V; this is suitable for low-power tunnel diode SRAM applications. The JP increased as the spacer thickness increased from 2.5nm to 5nm. As the spacer thickness increased above 5nm, the Jp decreased. Using a low-current-density in this paper, a bread-boarded one-transistor tunneling-based SRAM (TSRAM) memory cell with low standby power consumption was demonstrated, where the standby power of this 1T TSRAM is estimated to be 65nW/cell using the 10-?m diameter RITDs. The result demonstrates the potential of Si-based tunnel diodes for low-power memory applications.

Practical transceivers have hardware impairments, which may affect the data rate of a system. In this paper, two way relaying with hardware losses is considered and is different from previous methods, which considers only ideal hardware case. Here both hops are subjected to independent and non-identical distributed nakagami-m fading variants with Amplify-and-Forward (AF) protocol and Decode-and-forward (DF) protocol. Hardware impairments are calculated at source, relay and destination. The outage probability is calculated with a function effective end-to-end signal-to-noise-and-distortion ratio (SNDR). In a similar way ergodic capacity also achieved. For low SNR values losses will be less but substantial. And for high SNR values losses will increase without bounds. But for SNDR case, increasing SNR makes some constant value of threshold, which is inversely proportional to the SNDR, called SNDR ceiling. Finally, this paper suggests the design guidelines for selecting hardware equipment to overcome hardware impairments with maximum extent.

A Orthogonal Frequency Division Multiplexing (OFDM) scheme offers high spectral efficiency and better resistance to fading environments. In OFDM the data is modulated using multiple number of sub-carriers that are orthogonal to each other because of which the problems associated with other modulation schemes such as Inter Symbol Interference (ISI) and Inter Carrier Interference (ICI) are reduced. This paper deals with the analysis of OFDM System utilising different modulation techniques (QAM and BPSK) over Rayleigh, Rician and Additive White Gaussian Noise (AWGN) fading environments with the use of pilot aided arrangement and finally the results are conveyed.

Digital image processing is now increasingly being used in electron accelerators to characterize electron beam. Measurement of electron beam parameters like beam size, beam centroid with high accuracy is required to optimize accelerator performance. Measurement accuracy of these parameters using digital image processing is limited by the noise present in the images. Reduction of noise without altering the features present in the image is a desired goal of image processing. In this paper we evaluate the noise reduction capability of median, mean, gaussian and wiener filters from digital images of electron beam image. The images were collected from Transport Line-1 in Indus Accelerator Complex at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India. We also evaluate the effect of these filters on the measurement accuracy of beam parameters like beam size and beam centroid. It has been observed that performance of median filter for noise reduction is better than mean, gaussian and wiener filter. Median filter also creates less distortion in beam size and centroid of the beam in comparison with other filters.

This paper presents the development and implementation of a new and practical fuzzy switching position controller for process industry control. Compatible with the structure of a bang–bang controller, a two-input fuzzy switching position controller with five rules is proposed. The idea is based on constructing a fuzzy switching control law which is functionally analogous to a traditional bang–bang controller. Fuzzy logic rules are used to enable an improved version of the conventional bang–bang control. The objective is to replace the conventional bang–bang controller with the proposed fuzzy switching position controller. A modified three-stage bang–bang controller is also designed and implemented. This controller is tested under the same conditions as that of the proposed fuzzy switching position controller, and its performance is used as a basis of comparison by which both controllers are measured. Both controllers are developed using MATLAB using the position control of a brushless dc motor drive found in the majority of these new robotic devices. Simulation Results shows that the fuzzy switching position controller produces adequate control performance, particularly in handling nonlinearities and external disturbances. The efficacy of the fuzzy switching position controller is demonstrated by its positive results, practicality, and feasibility in the process industry sector, when compared with a modified traditional bang–bang controller.

Network Interface Module (NIM) is a front-end receiver block, which interfaces incoming signals from outside world in to the High Definition (HD) Radio Frequency (RF) receivers. In most of the cases, NIM receives only one type of signal and down converts RF in to Intermediate Frequency (IF). In modern receivers there could be a separate block for this signal interface or there could be single silicon which acts as network interface module, Tuner and demodulator. Introduction of modularity concept in the front-end block of receivers will helps to enhance the performance of the receivers as and when required.