Differential evolution approach for optimal reactive power dispatch

Differential evolution based optimal reactive power dispatch for real power loss minimization in power system is presented in this paper. The proposed methodology determines control variable settings such as generator terminal voltages, tap positions and the number of shunts to be switched, for real power loss minimization in the transmission system. The problem is formulated as a mixed integer nonlinear optimization problem. A generic penalty function method, which does not require any penalty coefficient, is employed for constraint handling. The formulation also checks for the feasibility of the optimal control variable setting from a voltage security point of view by using a voltage collapse proximity indicator. The algorithm is tested on standard IEEE 14, IEEE 30, and IEEE 118-Bus test systems. To show the effectiveness of proposed method the results are compared with Particle Swarm Optimization and a conventional optimization technique – Sequential Quadratic Programming.     

Network loss minimization with voltage security using differential evolution

This paper presents a differential evolution (DE) based optimal power flow (OPF) for reactive power dispatch in power system planning studies. DE is a simple population-based search algorithm for global optimization and has a minimum number of control parameters. The problem is formulated as a mixed integer non-linear optimization problem taking into account both continuous and discrete control variables. The proposed method determines control variable settings such as generator voltages (continuous), tap positions (discrete) and the number of shunt reactive compensation devices to be switched (discrete) for real power loss minimization in the transmission system using DE algorithm. Most of the evolutionary algorithm applications to optimization problems apply penalty function approach to handle the inequality constraints, involving penalty coefficients. The correct combination of these coefficients can be determined only by a trial and error basis. In the proposed approach, the inequality constraints are handled by penalty parameterless scheme. Voltage security margin was evaluated using continuation power flow (CPF), to ensure the feasibility of the optimal control variable setting. The suitability of the method was tested on IEEE 14 and IEEE RTS 24-bus systems and results compared with sequential quadratic programming (SQP) method. The DE provides near global solutions comparable to that obtained using SQP.     

Cross-linking decrystallized and partially acetylated cotton yarn with dimethylol–dihydroxy–ethylene–urea

Easy-care finishing of cotton fabrics invariably results in the loss of mechanical properties of the fabrics. There have been many attempts from time to time by different workers to reduce the above loss in the mechanical properties. But the problem is yet to be resolved satisfactory. As the uniform distribution of cross-links in the resin-finished structure of cellulose is the key for achieving a better balance of mechanical properties, the present work aims at a suitable modification of the cellulose matrix to achieve the goal. The paper reports the mechanical properties of the modified and cross-linked cotton yarn. The cross-linked samples of the modification treatment involving swelling the yarn at normal stretch with 20% NaOH and partially acetylating without washing off the alkali have displayed higher tenacity, elongation, and toughness, with better easy-care properties as compared to the control.     

Joint Estimation of Human Pose and Conversational Groups from Social Scenes

Despite many attempts in the last few years, automatic analysis of social scenes captured by wide-angle camera networks remains a very challenging task due to the low resolution of targets, background clutter and frequent and persistent occlusions. In this paper, we present a novel framework for jointly estimating (i) head, body orientations of targets and (ii) conversational groups called F-formations from social scenes. In contrast to prior works that have (a) exploited the limited range of head and body orientations to jointly learn both, or (b) employed the mutual head (but not body) pose of interactors for deducing F-formations, we propose a weakly-supervised learning algorithm for joint inference. Our algorithm employs body pose as the primary cue for F-formation estimation, and an alternating optimization strategy is proposed to iteratively refine F-formation and pose estimates. We demonstrate the increased efficacy of joint inference over the state-of-the-art via extensive experiments on three social datasets.     

Acidity of heteropoly compounds from XPS measurements

The changes in the partial charges on oxygens in the various heteropoly salts as a result of the acidity differences have been exploited for probing the oxygen 1s and W 4f lines. The gradation of the acidity thus obtained is compared to that of the conventional method.     

Testing and Modeling Two Rockfill Materials

Modeled rockfill materials consisting of rounded and angular particles obtained from two dam sites are subjected to drained triaxial tests using large size specimens. An elastoplastic constitutive model based on the disturbed state concept is adopted to characterize the behavior of the modeled rockfill materials. The material parameters for the two rockfill materials are determined from the experimental results. The variation of the material parameters with respect to the size of the particles for the rockfill material with the rounded particle is, in general, opposite to that for the rockfill material with the angular particles. The model is shown to provide satisfactory prediction of the behavior of the rockfill materials tested. Material parameters are predicted for prototype size of rockfill materials.     

Correction to: Efficient Algorithm for Identification and Cache Based Discovery of Cloud Services

Mobile Networks and Applications - The original version of this article unfortunately contained a mistake in the author group section. Author “V. Varadarajan” should be expanded to...