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Kākināda, India

Naresh G.,Pragati engineering college | Narasimham S.V.L.,JNTUH College of Engineering | Ravindra K.,Jawaharlal Nehru Technological University Kakinada
International Review on Modelling and Simulations | Year: 2011

Power system stabilizers (PSSs) are used to generate supplementary control signals for the excitation system to damp electromechanical oscillations. This paper presents a particle swarm optimization based approach for tuning the parameters of PSSs in multi-machine power systems. The stabilizers are tuned to simultaneously shift the undamped and lightly damped electromechanical modes of all plants to a prescribed zone in the s-plane. A multiobjective problem is formulated to optimize a composite set of objective functions comprising the damping factor and the damping ratio of lightly damped electromechanical modes. The performance of the proposed PSSs under different disturbances, loading conditions, and system configurations is investigated on two multi-machine power systems. The non-linear simulation results are presented under wide range of operating conditions; disturbances at different locations show the effectiveness and robustness of the proposed PSSs and their ability to provide efficient damping of low frequency oscillations. © 2011 Praise Worthy Prize S.r.l. - All rights reserved. Source

Naresh G.,Pragati engineering college | Ramalinga Raju M.,Andhra University | Narasimham S.V.L.,JNTUH College of Engineering
Swarm and Evolutionary Computation | Year: 2016

Power System Stabilizers (PSS) are generally employed to damp electromechanical oscillations by providing auxiliary stabilizing signals to the excitation system of the generators. But it has been found that these Conventional PSS (CPSS) do not provide sufficient damping for inter-area oscillations in multi-machine power systems. Thyristor Controlled Series Capacitor (TCSC) has immense potential in damping of inter-area power swings and in mitigating the sub-synchronous resonance. In this paper Improved Harmony Search Algorithm (IHSA) has been proposed for coordinated design of multiple PSS and TCSC in order to effectively damp the oscillations. The results obtained by using IHSA on WSCC 3-machine, 9-bus system are found to be superior compared to the results obtained using Bacterial Swarm Optimization (BSO) algorithm. The damping performance of conventional PSS and TCSC controllers is also compared with coordinated design of IHSA based PSS and TCSC on New England 10-machine, 39-bus system over wide range of operating conditions and contingencies. To demonstrate the effectiveness of the proposed technique the results obtained on this test system are also compared with the results obtained with Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Harmony Search Algorithm (HSA) and Bacterial Swarm Optimization (BSO). © 2015 Elsevier B.V. All rights reserved. Source

Lakshmi N.,Pragati engineering college
International Journal of Applied Environmental Sciences | Year: 2013

The present study deals with the effect of lead (Pb+2) on seed germination on groundnut (Arachis hypogea L. Var TMV-2) in solution as well as pot experimental studies. Three test concentrations of lead (Pb+2)10.2ppm, 102ppm, 1020ppm are taken in a solution as well as a pot (soil) culture besides a test control to grow the groundnut species. Effect of lead in germination success and seedling characteristics were studied in test species grown in above test concentrations of lead, besides control. © Research India Publications. Source

Madireddy R.M.,Pragati engineering college | Gottumukkala P.S.V.,SRKR Engineering College | Murthy P.D.,Jawaharlal Nehru Technological University Kakinada | Chittipothula S.,Jawaharlal Nehru Technological University Kakinada
Cellular and Molecular Life Sciences | Year: 2014

The complexity in shape context method and its simplification is addressed. A novel, but simple approach to design shape context method including Fourier Transform for the object recognition is described. Relevance of shape context, an important descriptor for the recognition process is detailed. Inclusion of information regarding all the contour points (with respect to a reference point) in computing the distribution is discussed. Role of similarity checking the procedure details regarding the computation of matching errors through the alignment transform are discussed. Present case of shape context (for each point with respect to the centroid) descriptor is testified for its invariance to translation, rotation and scaling operations. Euclidean distance is used during the similarity matching. Modified shape context based descriptor is experimented over three standard databases. The results evidence the relative efficiency of the modified shape context based descriptor than that reported for other descriptor of concurrent interests. © 2014 Madireddy et al.; licensee Springer. Source

Sirisha D.,Pragati engineering college | Vijayakumari G.,JNTUH College of Engineering
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

Heterogeneous computing systems require efficient task-to-processor mapping for attaining high performance. Scheduling workflows on heterogeneous environments is shown to be NP-Complete. Several heuristics were developed to attain minimum schedule lengths. However, these algorithms employ level-wise approach of scheduling tasks. This indirectly assigns higher priority to the tasks at lower levels than those at higher levels. Further, the start time of tasks at higher levels is constrained by the completion times of tasks at lower levels. The present work proposes a novel heuristic based global scheduling algorithm namely Minimal Start Time (MST) algorithm for work- flows. The proposed approach focuses on minimizing the start times of tasks which are dependent on the tasks at lower levels to generate shorter span schedules. The primary merit of this scheme is due to the elimination of level constraints whenever there are no dependency constraints. The performance of MST algorithm is evaluated in terms of normalized makespan, speedup, efficiency and improvement of 5–20% in 80% of the cases is achieved in comparison to the earlier work. © Springer International Publishing Switzerland 2016. Source

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