Visvesvaraya National Institute of Technology
Nagpur, India

Visvesvaraya National Institute of Technology Nagpur , also referred to as NIT Nagpur, formerly Regional College of Engineering, Nagpur and Visvesvaraya Regional College of Engineering , is an engineering institute in Nagpur, Maharashtra, in central India. The institute has been ranked among the best fifteen engineering colleges in India. The institute was established in June 1960 and later named in honor of engineer, planner and statesman, Sir Mokshagundam Visvesvaraya. It is one of the National Institutes of Technology and in 2007 was conferred the status of Institute of National Importance. Wikipedia.

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Suryawanshi H.M.,Visvesvaraya National Institute of Technology
IEEE Transactions on Industrial Electronics | Year: 2010

In this paper, an approach to reduce common-mode voltage (CMV) at the output of multilevel inverter using 3-D space-vector modulation (SVM) is proposed. The 3-D SVM is superset of the traditional 2-D SVM, and thus, it inherits all the merits of traditional 2-D. A simple technique for the selection of switching states to constitute the reference vector is proposed here. The computational cost of the proposed technique is independent of voltage levels of inverter. This technique is easy to implement online in digital controller. The tradeoff between quality of output voltage and CMV is achieved in this paper. This paper realizes the implementation of 3-D SVM to reduce the CMV using a five-level diode-clamped inverter for a three-phase induction motor. Experimental and simulation results demonstrate the feasibility of the proposed technique. © 2010 IEEE.

Deshpande U.,Visvesvaraya National Institute of Technology
Applied Soft Computing Journal | Year: 2013

We propose a stock market portfolio recommender system based on association rule mining (ARM) that analyzes stock data and suggests a ranked basket of stocks. The objective of this recommender system is to support stock market traders, individual investors and fund managers in their decisions by suggesting investment in a group of equity stocks when strong evidence of possible profit from these transactions is available. Our system is different compared to existing systems because it finds the correlation between stocks and recommends a portfolio. Existing techniques recommend buying or selling a single stock and do not recommend a portfolio. We have used the support confidence framework for generating association rules. The use of traditional ARM is infeasible because the number of association rules is exponential and finding relevant rules from this set is difficult. Therefore ARM techniques have been augmented with domain specific techniques like formation of thematical sectors, use of cross-sector and intra-sector rules to overcome the disadvantages of traditional ARM. We have implemented novel methods like using fuzzy logic and the concept of time lags to generate datasets from actual data of stock prices. Thorough experimentation has been performed on a variety of datasets like the BSE-30 sensitive Index, the S & P CNX Nifty or NSE-50, S & P CNX-100 and DOW-30 Industrial Average. We have compared the returns of our recommender system with the returns obtained from the top-5 mutual funds in India. The results of our system have surpassed the results from the mutual funds for all the datasets. Our approach demonstrates the application of soft computing techniques like ARM and fuzzy classification in the design of recommender systems. © 2012 Elsevier B.V. All rights reserved.

Nageshwar Rao R.,Visvesvaraya National Institute of Technology | Pramod Chakravarthy P.,Visvesvaraya National Institute of Technology
Applied Mathematical Modelling | Year: 2013

In this paper, we present a finite difference method for singularly perturbed linear second order differential-difference equations of convection-diffusion type with a small shift, i.e., where the second order derivative is multiplied by a small parameter and the shift depends on the small parameter. Similar boundary value problems are associated with expected first-exit times of the membrane potential in models of neurons. Here, the study focuses on the effect of shift on the boundary layer behavior or oscillatory behavior of the solution via finite difference approach. An extensive amount of computational work has been carried out to demonstrate the proposed method and to show the effect of shift parameter on the boundary layer behavior and oscillatory behavior of the solution of the problem. © 2012 Elsevier Inc.

Bedekar P.P.,Visvesvaraya National Institute of Technology | Bhide S.R.,Visvesvaraya National Institute of Technology
IEEE Transactions on Power Delivery | Year: 2011

The time of operation of overcurrent relays (OCRs) can be reduced, and at the same time, the coordination can be maintained, by selecting the optimum values of time multiplier setting (TMS) and plug setting (PS) of OCRs. This paper presents hybrid genetic algorithm (GA)nonlinear programming (NLP) approach for determination of optimum values of TMS and PS of OCRs. GA has a drawback of, sometimes, converging to the values which may not be optimum, and NLP methods have a drawback of converging to local optimum values, if the initial choice is nearer to local optimum. This paper proposes a hybrid method to overcome the drawback of GA and NLP method, and determine the optimum settings of OCRs. The main contributions of this paper are1) systematic method for formulation of problem of determining optimum values of TMS and PS of OCRs in power distribution network as a constrained nonlinear optimization problem, 2) determining initial values of TMS and PS using GA technique and finding final (global optimum) values using NLP method, thus making use of the advantages of both methods (and at the same time overcoming the drawbacks of the methods). © 2010 IEEE.

Roul P.,Visvesvaraya National Institute of Technology
Communications in Theoretical Physics | Year: 2013

The purpose of the paper is to present analytical and numerical solutions of a degenerate parabolic equation with time-fractional derivatives arising in the spatial diffusion of biological populations. The homotopy - perturbation method is employed for solving this class of equations, and the time-fractional derivatives are described in the sense of Caputo. Comparisons are made with those derived by Adomian's decomposition method, revealing that the homotopy perturbation method is more accurate and convenient than the Adomian's decomposition method. Furthermore, the results reveal that the approximate solution continuously depends on the time-fractional derivative and the proposed method incorporating the Caputo derivatives is a powerful and efficient technique for solving the fractional differential equations without requiring linearization or restrictive assumptions. The basis ideas presented in the paper can be further applied to solve other similar fractional partial differential equations. © 2013 Chinese Physical Society and IOP Publishing Ltd.

Gawande V.B.,Visvesvaraya National Institute of Technology | Dhoble A.S.,Visvesvaraya National Institute of Technology | Zodpe D.B.,Visvesvaraya National Institute of Technology
Renewable and Sustainable Energy Reviews | Year: 2014

The performance characteristics of a solar heater and heat exchangers can be effectively improved by using artificial roughness in different forms, shapes and sizes. Artificial roughness is provided in the form of different geometries such as ribs, dimple shape roughness, wire mesh, baffles, delta winglets etc. To determine the effect of these geometries on thermal performance of solar heaters and heat exchangers, several experimental and numerical studies have been carried out by various researchers. In this paper, an attempt has been made to review various roughness element geometries employed in solar air heaters and heat exchangers in terms of heat transfer, friction factor and flow simulation techniques. Correlations developed for heat transfer and friction factor for different roughness geometries by various investigators in solar air heaters are presente. © 2014 Elsevier Ltd. All rights reserved.

Chatterjee A.,Visvesvaraya National Institute of Technology
Journal of Sound and Vibration | Year: 2010

Vibration measurements offer an effective, inexpensive and fast means of non-destructive testing of structures and various engineering components. There are mainly two approaches to crack detection through vibration testing; open crack model with emphasis on changes in modal parameters and secondly, the breathing crack model focusing on nonlinear response characteristics. The open crack model based on linear response characteristics can identify the crack only at an advanced stage. Researchers have shown that a structure with a breathing crack behaves more like a nonlinear system, similar to that of a bilinear oscillator and the nonlinear response characteristics can very well be investigated to identify the presence of the crack. In the present study, the bilinear restoring force is approximated by a polynomial series and a nonlinear dynamic model of the cracked structure is developed using higher order frequency response functions. The effect of crack severity on the response harmonic amplitudes are investigated and a new procedure is suggested whereby the crack severity can be estimated through measurement of the first and second harmonic amplitudes. © 2010 Elsevier Ltd. All rights reserved.

Chatterjee A.,Visvesvaraya National Institute of Technology
International Journal of Mechanical Sciences | Year: 2010

Use of Volterra series in nonlinear system identification is well established now. The series represents response of a nonlinear system in a functional series form consisting of convolution integrals involving higher-order impulse response functions known as Volterra kernels. Multi-dimensional Fourier transforms of these Volterra kernels give the higher-order frequency response functions (FRFs). The measurement of these FRFs under harmonic excitation and their relationship with the first-order FRFs provide a basis for estimation of the nonlinear parameters. However, most of the methods employ single-tone excitation, which provide limited FRF measurement in a single experiment. In the present study, a novel procedure based on multi-tone excitation is presented for a typical Duffing oscillator and it is demonstrated that accurate estimation of both nonlinear and linear parameters is possible with fewer number of experiments. © 2010 Elsevier Ltd. All rights reserved.

Chatterjee A.,Visvesvaraya National Institute of Technology
International Journal of Non-Linear Mechanics | Year: 2010

Identification of non-linear systems is mainly limited to polynomial form non-linearities. Among the non-polynomial forms, bilinear oscillator constitutes an important class of non-linear systems and it has been used for modeling of various physical systems, particularly for structural elements with a breathing crack. An identification procedure is presented here for the class of bilinear oscillator, using higher order FRFs derived from Volterra series under harmonic excitation. The procedure addresses the problem of both; identification of the non-linearity structure as well as estimation of the bilinear parameter, which can be correlated to the crack severity and structural degradation. The procedure is illustrated with numerical simulation and the estimation results indicate that even a weakly bilinear state introduced by a small crack size can be accurately identified and measured. © 2009 Elsevier Ltd.

Sharma S.K.,Visvesvaraya National Institute of Technology | Kalamkar V.R.,Visvesvaraya National Institute of Technology
Renewable and Sustainable Energy Reviews | Year: 2014

Enhancement of heat transfer in the solar air heater ducts can be achieved by several means like using baffles, fins, ribs and groves. Until now, various attempts have been made to investigate the effects of these geometries on the enhancement of the heat transfer rate; however it is achieved at the cost of the increase in the pressure drop across the surfaces on which these elements are mounted. This paper is an attempt to summarize and conclude the investigations involving the use of small height elements and surface protrusions on absorber plate and channel walls as artificial roughness elements of various geometries and its effect on heat transfer and friction factor through experiments. It also summarizes the various correlations which have been developed for Nusselt number (Nu) and Friction factor (f) and reported in the previous investigations. The comparative study has been done to understand the results of these investigations for solar air heaters with different roughness elements on its absorber surface. © 2014 Elsevier Ltd.

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