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Kumari S.,Vellore Institute of Technology | Mohana Priya A.,Vellore Institute of Technology | Lulu S.,Vellore Institute of Technology | Tauqueer M.,Cognizant Technology Solutions
Journal of Theoretical Biology | Year: 2014

Ribosomal phosphoprotein P1 (RPP1) is acidic phosphoprotein which in association with neutral phosphoprotein P0 and acidic phosphoprotein P2 forms ribosomal P protein complex as (P1)2-P0-(P2)2. P protein is known to be immunogenic and has important role in protein translation. 3D structure of P1 is not known. We have built an ab-initio model of RPP1 of Plasmodium falciparum using I-TASSER. Stereochemical stability of structure was checked using PROCHECK and the normality of the local environment of amino acids was checked using WHATIF. Comparison between known protein structures in PDB database and model protein was done using Dali server. Molecular dynamic simulation study and virtual screening of RPP1 was carried out. Three dimensional model structure of RPP1 was generated and model validation studies proved the model to be steriochemically significant. RPP1 structure was found to be stable at room temperature in water environment demonstrated by 30ns molecular dynamic simulation study. Dali superimposition showed 69% superimposition to known 3D structures in PDB. Further virtual screening and docking studies promoted good interaction of ligands Ecgonine, Prazepam and Ethyl loflazepate with RPP1. The work provides insight for molecular understanding of RPP1 of P. falciparum and can be used for development of antimalarial drugs. © 2013 Elsevier Ltd. Source


Kundu J.,Cognizant Technology Solutions | Mukherjee A.,Bengal Engineering and Science University
International Journal of Industrial and Systems Engineering | Year: 2012

Like light, which has a wave-particle dual nature, IT entities also exhibit duality in terms of being a product as well as service. But, unlike daylight, IT entities come at a price. The concepts of industrial engineering have to be considered with a service-sector orientation to arrive at an effective pricing strategy for IT entities. With the proliferation of outsourcing of IT to offshore locations, the concerns regarding the productivity of the personnel are increasing. The benefits of offshoring are partly neutralised by the lesser productivity and higher management overhead. This paper recommends a new pricing model which leverages Weibull distribution modelling of the software maintenance service requests. We have applied the predetermined prices suggested by the model on live projects, and observe that it has eliminated the productivity concerns and reduced the management overhead significantly. Copyright © 2012 Inderscience Enterprises Ltd. Source


Iyer G.N.,National University of Singapore | Veeravalli B.,National University of Singapore | Krishnamoorthy S.G.,Cognizant Technology Solutions
IEEE Transactions on Aerospace and Electronic Systems | Year: 2012

Large-scale polynomial product computations often used in aerospace applications such as satellite image processing and sensor networks data processing always pose considerable challenge when processed on networked computing systems. With non-zero communication and computation time delays of the links and processors on a networked infrastructure, the computation becomes all the more challenging. In this research, we attempt to investigate the use of a divisible load paradigm to design efficient strategies to minimize the overall processing time for performing large-scale polynomial product computations in compute cloud environments. We consider a compute cloud system with the resource allocator distributing the entire load to a set of virtual CPU instances (VCI) and the VCIs propagating back the processed results to resource allocator for postprocessing. We consider heterogeneous networks in our analysis and we derive fundamental recursive equations and a closed-form solution for the load fractions to be assigned to each VCI. Our analysis also attempts to eliminate any redundant VCI-link pairs by carefully considering the overheads associated with load distribution and processing. Finally, we quantify the performance of the strategies via rigorous simulation studies. © 2006 IEEE. Source


Umamaheswari M.G.,Anna University | Umamaheswari M.G.,RMK Engineering College | Uma G.,Anna University | Vijayalakshmi K.M.,Cognizant Technology Solutions
IET Power Electronics | Year: 2013

In this study, the analysis and design of reduced-order sliding-mode controller (ROSMC) for power factor correction (PFC) in a three-phase system is presented. A new and systematic technique for the selection of sliding surface co-efficients to implement ROSMC is attempted. The front end is a three-phase diode rectifier followed by DC-DC Cuk converter modules with the common DC output. Instantaneous symmetrical component theory is used for reference current generation. The control strategy uses three inner ROSMC current controllers for source current shaping and an outer voltage loop using proportional integral controller for load voltage regulation. The proposed method offers simple control strategy, fast transient response and power factor close to unity. To validate the proposed method, a prototype controlled by dSPACE 1104 signal processor is set up. Simulation and experimental results indicate that the proposed system offers regulated output voltage for wide load variations and power factor close to unity. © The Institution of Engineering and Technology 2013. Source


Umamaheswari M.G.,Anna University | Uma G.,Anna University | Vijayalakshmi K.M.,Cognizant Technology Solutions
IET Power Electronics | Year: 2011

This study discusses a simple sliding surface design approach of a reduced-order sliding mode controller (ROSMC) for power factor correction, wherein a new and systematic technique for the selection of sliding surface co-efficients to implement ROSMC is attempted. Pade's approximation technique is used to obtain the reduced-order model. A prototype of front-end AC-DC converter followed by DC-DC Cuk converter controlled by ROSMC using a dSPACE signal processor is set up for 60 W. Experimental results are presented to validate the simulation results. Simulation and experimental results reveal that ROSMC control can achieve good output voltage regulation and also provide improved robustness in shaping the input current in the presence of load variations. © 2011 The Institution of Engineering and Technology. Source

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