Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Development of an automated handwriting analysis system(2011) Kamath, V.; Ramaswamy, N.; Navin, P.; Desai, V.; Kulkarni, S.M.In the present study a method has been proposed for the behavioral prediction of a person through automated handwriting analysis. The present work identifies the psychological traits in the writing namely size, slant and pressure, baseline, number of breaks, margins, speed of writing and spacing between the words. The handwriting is analyzed through Image Processing in MATLAB. The behavioral pattern of the person is predicted from the above traits of the handwriting. The developed system identifies handwriting closely which may not be possible for a graphologist. It is real time and involves less image preprocessing. The proposed system is calibrated with manual analysis. The results obtained through the system are in good agreement to more than 80 percent of the cases with ideal manual analysis. © 2006-2011 Asian Research Publishing Network (ARPN).Item Quarter circular breakwater: Prediction of transmission using multiple regression and artificial neural network(Marine Technology Society Inc. mtsdir@erols.com, 2014) Goyal, R.; Singh, K.; Hegde, A.V.The physical model study of coastal structures is a nonlinear process influenced by innumerable parameters. As a result of a lack of definite systems, intricacies, and high costs involved in the physical models, we need a simple mathematical tool to predict wave transmission through quarter circular breakwater (QBW). QBW is a state-of-theart breakwater essentially based on the exploitation of the concepts of semicircular breakwater. This paper discusses the use of soft computing tools such as MATLAB based multiple regression (MR) and artificial neural network (ANN) to predict the wave transmission coefficient of QBW. To assess the accuracy of the proposed model and its ability to forecast, correlation coefficient and mean squared error are availed. On comparing the results obtained from MR and ANN, it is concluded that ANN gives more accurate results and can be used as a powerful tool for the modeling of hydrodynamic breakwater transmission through QBW. It serves as a viable alternative to the conventional physical model to simulate the hydrodynamic transmission performance of QBW.Item Fault diagnosis of deep groove ball bearing through discrete wavelet features using support vector machine(COMADEM International rajbknrao@btinternet.com, 2014) Vernekar, K.; Kumar, H.; Gangadharan, K.V.Bearings are the most important and frequently used machine components in most of the rotating machinery. In industry, breakdown of such crucial components causes heavy losses. So prevention of failure of such components is very essential. This paper presents an online fault detection of a bearing used in an internal combustion engine through machine learning approach using vibration signals of bearing in healthy and simulated faulty conditions. Vibration signals are acquired from bearing in healthy as well as different simulated fault conditions of bearing. The Discrete Wavelet Transform (DWT) features were extracted from vibration signals using MATLAB program. Decision tree technique (J48 algorithm) has been used for important feature selection out of extracted DWT features. Support vector machine is being used as a classifier and obtained results found with classification accuracy of 98.67%.The advantage of machine learning technique for fault diagnosis over conventional vibration analysis approach has demonstrated in this paper.Item Simplified and Improved Analytical Hierarchy Process Aid for Selecting Candidate Network in an Overlay Heterogeneous Networks(Kluwer Academic Publishers barbara.b.bertram@gsk.com, 2015) Chandavarkar, B.R.; Guddeti, G.R.M.Analytical hierarchy process (AHP) is one of the pairwise comparison, attributes weight calculation approach of multiple attribute decision making aid to select the candidate network for seamless handoff in an overlay heterogeneous network. The main challenging issue in AHP is manually computing the reciprocal matrix results in an inconsistency indicated by the consistency ratio >0.1. This paper proposes a simplified and improved AHP (SI-AHP), which accepts the perceived one-dimensional linguistic values of the attributes from the decision maker. Further, SI-AHP is used to automatically compute the reciprocal matrix for the attribute weights calculation with the minimum involvement of the decision maker resulting in reduced computational time and improved consistency. The consistency ratio of SI-AHP is further improved by deriving the reciprocal matrix of pairwise comparison of any one of the attribute to others. Using the MATLAB simulations, the proposed SI-AHP is evaluated for the consistency ratio of voice and download traffic and also for 78,125 different combinations of one-dimensional linguistic values of the attributes. SI-AHP’s weight calculated for the decision attributes is used in the multiple attribute decision making approach for selecting the candidate network in an overlay heterogeneous network. © 2015, Springer Science+Business Media New York.Item An adaptive reactive power perturbation based hybrid islanding detection method for distributed generation systems(Acta Press journals@actapress.com, 2016) Krishnan, G.; Gaonkar, D.N.The intentional islanding operation of distributed generation (DG) systems can bring many benefits to the DG owner, distribution network operators and customers. One of the requirements for intentional islanding operation is the successful detection of the grid events which can lead to islanding of the DG system. This paper presents the hybrid islanding detection method based on adaptive reactive power variation with a passive algorithm that relies on the transient response characteristics for facilitating islanding detection. The proposed method presented in this paper can overcome the problems in the reactive power variation based methods. Extensive studies are conducted for differentiating the transient characteristic features for islanded and non-islanded systems. In this study the adaptive reactive power sequence is modified to enhance the performance under sudden load changes. The proposed method proved to detect all probable islanding situations with minimum run-on time. The performance of the method is evaluated using simulation results obtained from MATLAB/SIMPOWERSYSTEMS software considering wind power based DG system.Item Modelling and analysis of a standalone PV/micro turbine/ ultra capacitor hybrid system(International Journal of Renewable Energy Research, 2016) Shalavadi, B.; Chowdary, V.; Yaragatti, R.Y.Nowadays the distributed generation is being vastly implemented due to its various advantages. Generally a non renewable source is connected in parallel to a renewable source. Normally Photo Voltaic (PV) generation gives the power necessary by the load. The output of the PV is varying due to various reasons like temperature, irradiation, etc. Distributed generation using micro turbine is a realistic solution because of its friendliness with environment, small in size and high efficiency of energy. If the load is more than PV power capability, micro turbine supplies the remaining power. Due to the varying load conditions, the micro turbine practically compensates all the PV fluctuations of power. Even so, to reduce the fast fluctuations of power, one need to use an energy storage system like battery, ultra capacitor and flywheel etc. Ultra capacitor has been chosen, because of the its high power density and very fast energy storing capability. This paper documents the simulation and analysis of a standalone Photovoltaic / Micro turbine hybrid system and Photovoltaic / Micro turbine / Ultra capacitor hybrid system using MATLAB/SIMULINK simulation software. The system is implemented based on the concept of a parallel hybrid configuration. The simulation results validate the proposal.Item Single-phase seven-level grid-connected photovoltaic system with ripple correlation control maximum power point tracking(International Journal of Renewable Energy Research, 2016) Sandeep, N.; Yaragatti, R.Y.This paper puts forward a control scheme for single-phase photovoltaic (PV) fed grid connected with cascade Hbridge (CHB) inverter. A unique control strategy based on the voltage ratio is proposed and is embedded with ripple correlation control (RCC) based maximum power point tracking (MPPT) to ensure the efficient energy conversion. The control scheme employed enables the independent operation and control of individual DC link voltage, ensuring the extraction of maximum power available from each PV panel. In addition, low harmonic grid currents are generated with an arbitrary power factor. Independent control of active and reactive power is exercised by decoupled component method. Numerical simulation was performed using the MATLAB/SIMULINK platform and results for three H-bridge cells connected in series are presented to support the theoretical concepts and control scheme proposed.Item Influence of ambient air relative humidity and temperature on thermal properties and unsteady thermal response characteristics of laterite wall houses(Elsevier Ltd, 2016) Saboor, S.; Ashok Babu, A.B.P.S.This paper presents the experimental investigation of the effect of ambient air humidity and temperature on thermal properties of the laterite rocks used in South-West coastal India. The experimental technique employed was transient plane source method in the saturated salt solution humidity controlled chamber. Experimental results showed an increase of thermal conductivity by 14.7% and specific heat by 9.15% with an increase in the relative humidity of ambient air in the hygroscopic range. A porous and ferruginous matrix of laterite was studied using a scanning electron microscope. The effects of relative humidity of the ambient air and temperature on the unsteady state thermal heat transfer characteristics such as transmittance, admittance, decrement factor, time lag, surface factor, surface factor time lag and heat capacity for different thicknesses of the laterite rock walls were investigated analytically. One dimensional heat flow equation under periodic convective boundary conditions was solved using matrix algebra and a computer simulation program which employs a cyclic admittance method was developed using MATLAB to compute unsteady state thermal characteristics. Results indicate that the decrement factor reduces by 8.35% and time lag increases by 2.88% with an increase in the relative humidity of ambient air compared to the dry state for the Indian standard laterite rock thickness. © 2016 Elsevier Ltd.Item Simplified and improved multiple attributes alternate ranking method for vertical handover decision in heterogeneous wireless networks(Elsevier, 2016) Chandavarkar, B.R.; Guddeti, G.R.Multiple Attribute Decision Making (MADM) is one of the best candidate network selection methods used for Vertical Handover Decision (VHD) in heterogeneous wireless networks (4G). Selection of the network in MADM is predominantly decided by two steps, i.e., attribute normalization and weight calculation. This dependency in MADM results in an unreliable network selection for handover, and in a rank reversal (abnormality) problem during the removal and insertion of the network in the network selection list. Hence, this paper proposes a Simplified and Improved Multiple Attributes Alternate Ranking method referred to as SI-MAAR to eliminate the attribute normalization and weight calculation methods, thereby solving the rank reversal problem. Further, the MATLAB simulation results demonstrate that the proposed SI-MAAR method outperforms MADM methods such as TOPSIS, SAW, MEW and GRA with respect to the network selection reliability and rank reversal problems. © 2015 Elsevier B.V. All rights reserved.Item A new control method to mitigate power fluctuations for grid integrated PV/wind hybrid power system using ultracapacitors(Walter de Gruyter GmbH info@degruyter.com, 2016) Sabhahit, N.S.; Gaonkar, D.N.The output power obtained from solar-wind hybrid system fluctuates with changes in weather conditions. These power fluctuations cause adverse effects on the voltage, frequency and transient stability of the utility grid. In this paper, a control method is presented for power smoothing of grid integrated PV/wind hybrid system using ultracapacitors in a DC coupled structure. The power fluctuations of hybrid system are mitigated and smoothed power is supplied to the utility grid. In this work both photovoltaic (PV) panels and the wind generator are controlled to operate at their maximum power point. The grid side inverter control strategy presented in this paper maintains DC link voltage constant while injecting power to the grid at unity power factor considering different operating conditions. Actual solar irradiation and wind speed data are used in this study to evaluate the performance of the developed system using MATLAB/Simulink software. The simulation results show that output power fluctuations of solar-wind hybrid system can be significantly mitigated using the ultracapacitor based storage system. © by De Gruyter 2016.