R. Dhanasekaran

Energy and coverage efficiency using straight line node deployment with data compression in Wireless sensor network

Wireless sensor networks (WSN) used to watch changes in an environment of a given field. Coverage, communication and connectivity of the network are the most fundamental challenges in WSN. Sensor nodes are mostly battery operated and expected to work for a longer time without replacing the batteries. The measure of the efficiency of a network usually defined about how efficient in sensing the given physical ambience. Energy efficient coverage of sensor nodes in Wireless sensor network is essential and has lots of scopes in the area for research. Connectivity can defined the ability of the sensor to reach the data sink. Finding a best node deployment policy that offers high degree of coverage with network connectivity is quite demanding. In this paper we are discussing about energy-efficient coverage with an innovative node topology.

Efficient demosaicking of color images using theoretic reconstruction technique

Demosaicking is the process of obtaining a RGB (Red, Green and Blue) Image from the Color filter Array (CFA) applied color Image . In general a good demosaicking algorithm reduces the low frequency information of imagery, since such information is not essential for image visual quality. This paper proposes an influential demosaicking technique that uses constraint sets to reconstruct a full color resolution channel for Bayer CFA samples. The proposed algorithm produces high frequency information of imagery such as possible. This iterative set theoretic reconstruction technique converges to a fixed point which is in fact solution to the demosaicking problem. Experimental results of the proposed method is much better than compare to other latest demosaicking algorithms in terms of image quality and Peak signal to Noise ratio (PSNR).

Intelligent controller based speed control of front end asymmetric converter fed switched reluctance motor

Switched Reluctance Motor (SRM) is increasing prominence due to its simple and rugged construction, absence of winding on its rotor, low manufacturing cost, high power density, fault tolerant capability. These advantages with SRM are overshadowed by the existence of torque ripple, noise vibration, requirement of rotor position information, complex control due to the nonlinear characteristics. This paper presents a new drive circuit for switched reluctance motor for controlling the speed using intelligent technique like Fuzzy Logic Controller (FLC). The FLC has turned into a critical system in control building. This paper presents the fuzzy logic controller for speed control of SRM. The controller tracks the exact speed response than PID controller. The simulation results reveal that the FLC gives the better performance in SRM. The Fuzzy Logic Controller has quick reacted, effectively altered, less expensive to execute and does not require any numerical modeling, smooth speed tracing with no crest overshoot when compared with conventional controller.

A review on design considerations of implantable antennas

Biotelemetry is the transmission of any physiological data from the Implantable Medical Devices (IMDs), implanted inside the human body to a remote place. These IMDs are widely used for both diagnostic and therapeutic applications. The important component used in IMDs is the miniaturized antenna that plays a crucial role in the design and development of IMDs. Numerous works have been proposed on the design of implantable antennas and the challenges related with biocompatibility, miniaturization, patient safety etc. This paper gives a review on related works carried out by various authors regarding the design of miniaturized antennas, testing and its performance evaluation in the field of biomedical telemetry.

High speed bit-parallel systolic multiplier over GF (2 m ) for cryptographic application

A bit parallel systolic multiplier in the finite field GF(2m) over the polynomial basis where irreducible polynomial generate the field GF(2m) is presented. The complexity of the proposed multiplier is compared in terms of area, latency and speed with the existing multiplier. The proposed multiplier has high throughput as compared with the traditional systolic multiplier. Moreover, this multiplier is highly regular, modular, and therefore, well-suited for VLSI implementation with fault tolerant design.

Capacitance computation of arbitrarily shaped conducting bodies by spacecraft surface charging analysis

This paper presents numerical estimation for the capacitance of an arbitrarily shaped conducting bodies based on the moment method with triangular patch modeling. The integral equation is evaluated numerically using a Gaussian quadrature method for triangles. The singular elements of the moment matrix are evaluated by using the Duffy transformation method. The Numerical data on the capacitance of conducting objects such as cuboid is presented. The computed results are compared with the previously published results. The findings of our study show that the Method of Moments is a more accurate method for the computation of free space capacitance.

Design and analysis of coupled inductor based high step-up DC-DC converter

This paper presents a steady state analysis of DC-DC Converter, including switched capacitors and a switched coupled inductor. By adopting the coupled inductor to charge switched capacitors during switch turn on period, the voltage gain can be effectively increased, and the turns ratio of the coupled inductor can be also reduced. In addition, the voltage stress of the active switch and diodes is clamped. Therefore, low voltage components can be adopted to reduce the conduction loss and cost, and conversion efficiency is improved. The operating principle and steady state analysis are discussed in this paper. The voltage gain of the proposed converter is 19.25 and the proposed converter is designed for output power 300W, with 12-V input voltage and 231-V output voltage.

Generating capability of modified switched reluctance machine for wind energy applications

The reduced weight due to the active parts makes reluctance machines a viable candidate for electro-mechanical applications. The critical choice in wind applications are on the capability of motoring and generative characteristics. Switched reluctance machines are viable candidate as with its extended constant power range operation replacing the conventional multi-gear transmission. Recently introduced dual magnetic circuit reluctance machine configuration makes it advantageous through the magnetic flux flow control. In this paper the dual magnetic circuit reluctance machines through double rotor is presented and compared with conventional machine for its power density. Further to evaluate the dynamic performance the proposed machine is compared with that of the conventional machine of same volume. The power density is increased by 68% at any operating speed and the motor constant square density is increased by 65% The average torque in case of the proposed machine is increased by 36% compared to that of the conventional machine.

Simulation modelling and fault analysis of switched reluctance motor

Switched Reluctance Motors (SRM) have the simple structure, ruggedness, reliability, high efficiency and inexpensive make it more attractive for industrial applications. This paper concentrates on the overview of SRMs faults and the performance analysis of motor under normal condition and faulty condition. The response of flux, current, torque and speed under normal condition and faulty conditions are compared to illustrate the fault analysis of the SRM drive under dynamic operating conditions. Also the causes and the effects of faults on torque ripple are discussed. Generally, there are two main faults in SRM such as winding faults and switching faults. The winding faults may be caused by mechanical vibration, heat, damage during installation, power converter fails, etc. These faults can cause effects in industrial environment and safety critical applications. Further, the early detection of fault reduces the faulty operation time and increases the lifetime of motor. The fault detection provides a great impact in controlling the electrical drive system. This setup is simulated by using MATLAB/Simulink and their results are presented.

Efficiency analysis of a new lossless passive snubber for electric vehicle applications

Power converters are used as Power Factor Correction (PFC) circuits for Electric Vehicle (EV) battery chargers. Snubber circuits are inevitable to increase power conversion efficiency, reduce switching losses and Electro Magnetic Interference (EMI) and offer safe operating range for a switch. Amid diverse kinds of snubber circuits, passive snubbers are ideal because of their simplicity and robustness. They can provide soft switching conditions without using extra switch. Consequently, the requirement of complicated gate drive and control circuit is eliminated. In this paper, a front end AC-DC PFC converter with a simple lossless passive snubber circuit is presented. The proposed lossless passive snubber helps the main switch to attain Zero Current Switching (ZCS) condition at turn on and Zero Voltage Switching (ZVS) condition at turn off instants, respectively. The proposed converter is analyzed theoretically with the equivalent circuits explaining the modes of operation. The simulation results at an output power of 1.5 kW load are presented to validate the feasibility of the proposed passive snubber. Even though the switch current stress is reduced to a greater extent some voltage stress is still present. The proposed PFC converter can achieve a Power Factor (PF) of 0.97 with Total Harmonic Distortion (THD) of 4.5%. The efficiency of the proposed circuit is calculated as 94% over wide operating range.