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Jasmin E.A.,Government Engineering College at Thrissur | Jagathy Raj V.P.,Cochin University of Science and Technology
International Journal of Electrical Power and Energy Systems | Year: 2011

This paper presents Reinforcement Learning (RL) approaches to Economic Dispatch problem. In this paper, formulation of Economic Dispatch as a multi stage decision making problem is carried out, then two variants of RL algorithms are presented. A third algorithm which takes into consideration the transmission losses is also explained. Efficiency and flexibility of the proposed algorithms are demonstrated through different representative systems: a three generator system with given generation cost table, IEEE 30 bus system with quadratic cost functions, 10 generator system having piecewise quadratic cost functions and a 20 generator system considering transmission losses. A comparison of the computation times of different algorithms is also carried out. © 2011 Elsevier Ltd. All rights reserved.

Ahammed M.M.,Sardar Vallabhbhai National Institute of Technology, Surat | Meera V.,Government Engineering College at Thrissur
Journal of Hazardous Materials | Year: 2010

The present study was conducted to compare the performance of a dual-media filter consisting of manganese oxide-coated (MOCS) and iron hydroxide-coated sand (IOCS) with that of IOCS filter and uncoated sand filter in treating water contaminated by microorganisms, heavy metals and turbidity with a view to its use in simple household water purification devices in developing countries. Long-duration column tests were conducted using two natural waters namely, roof-harvested rainwater and canal water. Performance of the filters showed that dual-media filter was more efficient in removing bacteria and heavy metals compared to IOCS filter, while uncoated sand filter showed very poor performance. The average effluent levels for dual-media filter when tested with rainwater were: turbidity 1.0 ± 0.1. NTU; total coliforms 3 ± 2. MPN/100. mL; heterotrophic plate count 170 ± 20. CFU/mL; zinc 0.06 ± 0.01. mg/L, while that for IOCS filter were: turbidity 1.0 ± 0.1. NTU; total coliforms 4 ± 2. MPN/100. mL; heterotrophic plate count 181 ± 37. CFU/mL; zinc 0.20 ± 0.07. mg/L. Similar results were obtained for canal water also. Up to 900 bed volumes (BV) could be treated without affecting the efficiency in the case of rainwater, while the filter operation had to be terminated after 500. BV due to excessive headloss in the case of canal water. The study thus showed the potential of the dual-media for use in low-cost household water filters for purification of natural waters. © 2010 Elsevier B.V.

Poulose S.,Indian Institute of Technology Madras | Panda T.,Indian Institute of Technology Madras | Nair P.P.,Government Engineering College at Thrissur | Theodore T.,Institute of Chemical Technology
Journal of Nanoscience and Nanotechnology | Year: 2014

Metal nanoparticles have unique optical, electronic, and catalytic properties. There exist well-defined physical and chemical processes for their preparation. Those processes often yield small quantities of nanoparticles having undesired morphology, and involve high temperatures for the reaction and the use of hazardous chemicals. Relatively, the older technique of bioremediation of metals uses either microorganisms or their components for the production of nanoparticles. The nanoparticles obtained from bacteria, fungi, algae, plants and their components, etc. appear environment-friendly, as toxic chemicals are not used in the processes. In addition to this, the formation of nanoparticles takes place at almost normal temperature and pressure. Control of the shape and size of the nanoparticles is possible by appropriate selection of the pH and temperature. Three important steps are the bioconversion of Ag+ ions, conversion of desired crystals to nanoparticles, and nanoparticle stability. Generally, nanoparticles are characterized by the UV-visible spectroscopy and use of the electron microscope. Silver nanoparticles are used as antimicrobial agents and they possess antifungal, anti-inflammatory, and anti-angiogenic properties. This review highlights the biosynthesis of silver nanoparticles by various organisms, possible mechanisms of their synthesis, their characterization, and applications of silver nanoparticles. © 2014 American Scientific Publishers.

Vanchipura R.,Government Engineering College at Thrissur | Sridharan R.,National Institute of Technology Calicut
International Journal of Advanced Manufacturing Technology | Year: 2013

This paper focuses on the problem of determining a permutation schedule for n jobs in an m-machine flow shop that operates in a sequence-dependent setup time (SDST) environment. Two constructive heuristic algorithms are developed with the minimisation of makespan as the objective. The first heuristic algorithm termed as setup ranking algorithm obtains the sequence using the setup times of jobs only. The second heuristic algorithm, fictitious job setup ranking algorithm (FJSRA), is developed using the concept of fictitious jobs. Pairs of jobs with minimum setup time between them constitute the fictitious jobs. Both these algorithms are compared with an existing constructive algorithm. For the purpose of experimentation, Taillard benchmark problems are used to develop SDST benchmark problems at eight different levels of sequence-dependent setup times. Graphical analysis, relative performance index analysis and statistical analysis are carried out on the results obtained for all the eight sets of benchmark problems. The analysis reveals that FJSRA emerges as the better algorithm for larger problems and for smaller problems with higher level of setup time. The results of statistical analysis are used to develop setup time dominance matrix for deciding upon the algorithm to be used for a particular size of problem. © 2012 Springer-Verlag London.

Sajeena Beevi B.,Government Engineering College at Thrissur | Madhu G.,Cochin University of Science and Technology | Sahoo D.K.,Cochin University of Science and Technology
Waste Management | Year: 2015

Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45days in a lab-scale batch experiment for total solid concentration of 100g/L for investigating the start-up performances under thermophilic condition (50°C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9L/kg VS (volatile solid) for the total solid (TS) concentration of 100g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249day-1. © 2014 Elsevier Ltd.

Navas K.A.,Government Engineering College at Thrissur | Sasikumar M.,Marian Engineering College
IETE Technical Review (Institution of Electronics and Telecommunication Engineers, India) | Year: 2011

All multimedia signal processing algorithms need suitable fidelity metrics for validating the results. Audio, image, and video are the major signals associated with multimedia, and the researchers rely upon objective metrics rather than subjective metrics due to pragmatic and uneconomic aspects of the latter. This paper analyses the available human visual system (HVS)-based objective fidelity metrics for the image processing, and highlights the inadequacy of the metrics for a special set of images known as region-of-interest (ROI) images and discusses a few research directions in this area. Copyright © 2011 by the IETE.

Sudharshan Kaarthik R.,Indian Institute of Science | Gopakumar K.,Indian Institute of Science | Mathew J.,Government Engineering College at Thrissur | Undeland T.,Norwegian University of Science and Technology
IEEE Transactions on Industrial Electronics | Year: 2015

Multilevel inverters with dodecagonal (12-sided polygon) voltage space vector structure have advantages, such as complete elimination of fifth and seventh harmonics, reduction in electromagnetic interference, reduction in device voltage ratings, reduction of switching frequency, extension of linear modulation range, etc., making it a viable option for high-power medium-voltage drives. This paper proposes two power circuit topologies capable of generating multilevel dodecagonal voltage space vector structure with symmetric triangles (for the first time) with minimum number of dc-link power supplies and floating capacitor H-bridges. The first power topology is composed of two hybrid cascaded five-level inverters connected to either side of an open-end winding induction machine. Each inverter consists of a three-level neutral-point-clamped inverter, which is cascaded with an isolated H-bridge making it a five-level inverter. The second topology is for a normal induction motor. Both of these circuit topologies have inherent capacitor balancing for floating H-bridges for all modulation indexes, including transient operations. The proposed topologies do not require any precharging circuitry for startup. A simple pulsewidth modulation timing calculation method for space vector modulation is also presented in this paper. Due to the symmetric arrangement of congruent triangles within the voltage space vector structure, the timing computation requires only the sampled reference values and does not require any offline computation, lookup tables, or angle computation. Experimental results for steady-state operation and transient operation are also presented to validate the proposed concept. © 2014 IEEE.

Prasanthkumar K.P.,Government Engineering College at Thrissur | Alvarez-Idaboy J.R.,National Autonomous University of Mexico
RSC Advances | Year: 2014

Oxidation of 2-aminopyrimidine (2Apy) by hydroxyl radicals (•OH) in aqueous medium has been studied using pulse radiolysis coupled to optical absorption and M05-2X/6-311++G(d,p) level DFT calculations aimed at elucidation of the reaction mechanism. The rate constant (k) 2.76 ± 0.06 × 109 M-1 s-1 determined by the pulse radiolysis method for the title reaction at neutral pH reflects a diffusion-controlled process. The maximum absorption wavelength (λmax 330 and 550 nm) of transient(s) remains intact in the pH range 10.5-7. Radical adduct formation (RAF) reactions with N1 (N3 is an identical site), C2, C4 (C6 is an identical site) and C5 as the target atoms, hydrogen transfer (HT) reaction with amino group and single electron transfer (SET) of 2Apy with •OH were modelled theoretically. Lowest Gibbs free energy of activation (ΔG ≠) in solution, 1.72 kcal mol-1, was calculated for RAF at C5; the computed k value for this process is 2.0 × 109 M-1 s-1 using the transition state theory (TST). The relative yield (87%) of this major product predicted from the computed k value shows excellent agreement with the results of the pulse radiolysis redox titrations. Subsequently, the possibilities for other RAF reactions, HT and SET were ruled out. As an extension to the above work, we have carried out a theoretical survey of the reactivity of •OH with 4-aminopyrimidine (4Apy); wherein the RAF at C5 is proposed as the most probable mechanism with a ΔG≠ of 2.15 kcal mol-1. © 2014 The Royal Society of Chemistry.

Mishmy T.S.,Government Engineering College at Thrissur | Sheeba V.S.,Government Engineering College at Thrissur
Proceedings - 2013 3rd International Conference on Advances in Computing and Communications, ICACC 2013 | Year: 2013

Developments in multi-carrier modulation systems have made communication, a fast growing field in the modern world. In the conventional OFDM systems use of cyclic prefix results in loss of capacity and the use of IFFT for modulation leads to poor spectral containment and high narrowband interference. To overcome these disadvantages filter bank based multicarrier system using cosine modulated filter bank has been proposed. The prototype filter for the CMFB system is developed using a lowpass Kaiser window from which the entire filter bank is developed. Peak to average Power Ratio (PAPR) is one of the main drawbacks of every multi-carrier system. PAPR reduction using clipping and companding methods are carried out and their performance is evaluated using CCDF plot and BER plot. © 2013 IEEE.

Vanchipura R.,Government Engineering College at Thrissur | Sridharan R.,National Institute of Technology Calicut
International Journal of Services and Operations Management | Year: 2014

This paper deals with the development and analysis of hybrid genetic algorithms for flow shop scheduling problems with sequence dependent setup time. A constructive heuristic called setup ranking algorithm is used for generating the initial population for genetic algorithm. Different variations of genetic algorithm are developed by using combinations of types of initial populations and types of crossover operators. For the purpose of experimentation, 27 group problems are generated with ten instances in each group for flow shop scheduling problems with sequence dependent setup time. An existing constructive algorithm is used for comparing the performance of the algorithms. A full factorial experiment is carried out on the problem instances developed. The best settings of genetic algorithm parameters are identified for each of the groups of problems. The analysis reveals the superior performance of hybrid genetic algorithms for all the problem groups. © 2014 Inderscience Enterprises Ltd.

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