Faculty Publications
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Publications by NITK Faculty
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Item Empirical validation of software development effort multipliers of intermediate COCOMO model(2008) Basavaraj, M.J.; Shet, K.C.Intermediate COCOMO Model computes effort as a function of program size and a set of cost drivers. Effort adjustment factor (EAF) is calculated using 15 cost drivers. EAF is an important significant factor in computing software development effort. We have taken one delivered development project of size of 479 function points and planned for 917 Person days of SEI CMM Level 5 "Excellent" Company as a case study to analyze the EAF. We have empirically validated the cost driver model for Intermediate COCOMMO using this projects data. Validation has been done by using other two development projects data of Excellent Company. From our analysis, we have found that cost drivers defined ratings need to be revisited for the projects of size less than 10 Person months. We have come out with ratings for some cost drivers where earlier it was not defined. This approach helps the project managers to anticipate and estimate the efforts for development projects preferably less than 10 Person months. We have achieved approximately 30% improvement in effort variance by following this approach. © 2008 Academy Publisher.Item Modeling and genetic algorithm-based multi-objective optimization of the MED-TVC desalination system(2012) Janghorban Esfahani, I.; Ataei, A.; Shetty K, K.V.; Oh, T.; Park, J.H.; Yoo, C.This study proposes a systematic approach of analysis and optimization of the multi-effect distillation-thermal vapor compression (MED-TVC) desalination system. The effect of input variables, such as temperature difference, motive steam mass flow rate, and preheated feed water temperature was investigated using response surface methodology (RSM) and partial least squares (PLS) technique. Mathematical and economical models with exergy analysis were used for total annual cost (TAC), gain output ratio (GOR) and fresh water flow rate (Q). Multi-objective optimization (MOO) to minimize TAC and maximize GOR and Q was performed using a genetic algorithm (GA) based on an artificial neural network (ANN) model. Best Pareto optimal solution selected from the Pareto sets showed that the MED-TVC system with 6 effects is the best system among the systems with 3, 4, 5 and 6 effects, which has a minimum value of unit product cost (UPC) and maximum values of GOR and Q. The system with 6 effects under the optimum operation conditions can save 14%, 12.5%, 2% in cost and reduces the amount of steam used for the production of 1m 3 of fresh water by 50%, 34% and 18% as compared to systems with 3, 4 and 5 effects, respectively. © 2012 Elsevier B.V..Item Design and analysis of dual output flyback converter for standalone PV/battery system(International Journal of Renewable Energy Research, 2017) Sabhahit, N.S.; Gaonkar, D.N.; Naik, A.In this paper, the cost comparison is carried out among flyback, forward and full bridge converters based upon the number of circuit components. The performance assessment in terms of efficiency of the PV array with MPPT controller using flyback and forward converter is detailed. The design and control of Photovoltaic/battery system using a flyback converter for stand-alone applications is presented. A flyback converter is used to get DC output along with an AC output for high frequency applications without employing an inverter. The PV/battery system uses photovoltaic array as the main source of power and a battery as the storage device. The energy input of the PV system is effectively utilized by adopting an MPPT technique and the storage battery is controlled to balance the load requirements using a bi-directional dc-dc converter. This system ensures that the load demand is satisfied under varying solar irradiance conditions and a constant voltage is maintained for different load conditions. The modelling and control strategy of the implemented system is realized in MATLAB/Simulink environment.Item Thermal and cost analysis of float and various tinted double window glass configurations on heat gain into buildings of hot & dry climatic zone in India(International Information and Engineering Technology Association info@iieta.org, 2018) Gorantla, G.; Saboor, S.; Setty, A.B.T.P.R.Glass window enclosures for buildings consume a lot of energy for affording thermal and visual comfort. Reducing solar radiation in summer and increase in winter through different double window glasses for making energy efficient building design is the theme of this paper. Therefore this work measures the spectral characteristics of four glasses namely grey, green, bronze and clear glasses in entire solar spectrum region from 300nm to 2500nm at normal angle of incidence by using Shimadzu UV 3600 spectrophotometer based on ASTM standards. To find the solar optical properties a MATLAB code was used which is based on British standards. To find the solar radiation transmission from different double window glass configurations and cost analysis from eight coordinal directions at peak summer and winter day were selected as per Indian standards with a MATLAB code to hot and dry climatic zone of Jodhpur (26.300N, 73.020E). From these results it is shows that in south direction all double glass windows are gaining less heat in summer and more heat in winter season when compared to other orientations. It is found that south orientation C1(Greyglasswindow-Airgap10mm-Greenglasswindow) and C12(Clearglasswindow-Airgap10mm-Bronzeglasswindow) configuration windows are gaining minimum and maximum heat in summer and winter respectively when compared to other configuration windows. Among all windows C1 configuration window is saving more cost annually. © 2018 International Information and Engineering Technology Association. All rights reserved.Item Combined radiogrammetry and texture analysis for early diagnosis of osteoporosis using Indian and Swiss data(Elsevier Ltd, 2018) Areeckal, A.S.; Kamath, J.; Zawadynski, S.; Kocher, M.; Sumam David, S.Osteoporosis is a bone disorder characterized by bone loss and decreased bone strength. The most widely used technique for detection of osteoporosis is the measurement of bone mineral density (BMD) using dual energy X-ray absorptiometry (DXA). But DXA scans are expensive and not widely available in low-income economies. In this paper, we propose a low cost pre-screening tool for the detection of low bone mass, using cortical radiogrammetry of third metacarpal bone and trabecular texture analysis of distal radius from hand and wrist radiographs. An automatic segmentation algorithm to automatically locate and segment the third metacarpal bone and distal radius region of interest (ROI) is proposed. Cortical measurements such as combined cortical thickness (CCT), cortical area (CA), percent cortical area (PCA) and Barnett Nordin index (BNI) were taken from the shaft of third metacarpal bone. Texture analysis of trabecular network at the distal radius was performed using features obtained from histogram, gray level Co-occurrence matrix (GLCM) and morphological gradient method (MGM). The significant cortical and texture features were selected using independent sample t-test and used to train classifiers to classify healthy subjects and people with low bone mass. The proposed pre-screening tool was validated on two ethnic groups, Indian sample population and Swiss sample population. Data of 134 subjects from Indian sample population and 65 subjects from Swiss sample population were analysed. The proposed automatic segmentation approach shows a detection accuracy of 86% in detecting the third metacarpal bone shaft and 90% in accurately locating the distal radius ROI. Comparison of the automatic radiogrammetry to the ground truth provided by experts show a mean absolute error of 0.04 mm for cortical width of healthy group, 0.12 mm for cortical width of low bone mass group, 0.22 mm for medullary width of healthy group, and 0.26 mm for medullary width of low bone mass group. Independent sample t-test was used to select the most discriminant features, to be used as input for training the classifiers. Pearson correlation analysis of the extracted features with DXA-BMD of lumbar spine (DXA-LS) shows significantly high correlation values. Classifiers were trained with the most significant features in the Indian and Swiss sample data. Weighted KNN classifier shows the best test accuracy of 78% for Indian sample data and 100% for Swiss sample data. Hence, combined automatic radiogrammetry and texture analysis is shown to be an effective low cost pre-screening tool for early diagnosis of osteoporosis. © 2018 Elsevier LtdItem Thermal and cost analysis of various air filled double glazed reflective windows for energy efficient buildings(Elsevier Ltd, 2020) Gorantla, G.; Saboor, S.; Vali, S.S.; Mahapatra, D.; Talanki Puttaranga Setty, A.B.; Kim, K.-H.The enormous amount of energy is being consumed by buildings in an attempt to deliver thermal comfort in buildings. This paper aims at reducing/increasing the total solar heat gain through various combinations of double glazed reflective windows of buildings. The spectral characteristics of six reflective glasses namely bronze, green, grey, opal blue, sapphire blue and gold-reflective glasses at a normal angle of incidence by using UV-3600 Shimadzu spectrophotometer according to ASTM E 424 standards were experimentally measured. The solar optical properties of the glasses were deduced by developing a MATLAB code using spectral data which was obtained from experiments in the solar spectrum wavelength range of 300 nm–2500 nm. Thirty air-filled double-glazed reflective windows have been studied for both thermal and cost analysis in the Indian composite climatic zone (New Delhi 28.580 N, 77.200 E). The configuration C13 (Grey reflective glass-Air gap 10 mm-Gold reflective glass) is observed to be the best air-filled double glazed window from the highest annual cost savings ($ 79.29 per annum in SE direction) and lower payback period (1.42 years) point of views among thirty double-glazed reflective glasses studied. The results of this paper are useful in the design of sustainable passive solar buildings. © 2019 Elsevier LtdItem Equilibrium analysis of dual-channel supply chain under retailer's greening cost information asymmetry(IGI Global journaleditor@igi-global.com, 2020) Rofin, T.M.; Mahanty, B.The purpose of this study is to investigate the impact of information asymmetry of retailer's greening cost on the performance of both the manufacturer and the retailer. The study considers a dual-channel supply chain comprising of a manufacturer and a retailer committed to green operations. The authors have employed sequential game theoretic model to derive the closed form expressions corresponding to the two cases under consideration, that is: (1) complete information and (2) asymmetric information. They have found that the sharing of greening cost information by the retailer can make both the manufacturer and the retailer better off in terms of profit. They have also found that the greening cost information sharing is all the more important when the greening cost efficiency is weak. The study helps retail managers to make a decision on whether to conceal or reveal the greening cost information with the upstream manufacturer. © 2020 IGI Global.Item Theoretical investigations of band alignments and SnSe BSF layer for low-cost, non-toxic, high-efficiency CZTSSe solar cell(Elsevier Ltd, 2021) Prabhu, S.; Pandey, S.K.; Chakrabarti, S.In this work, a numerical simulation approach is utilized using SCAPS-1D software to model, modify, optimize, and evaluate the CZTSSe solar cell structure. For the CZTSSe solar cell, one possible reason hindering the performance is improper band alignment between the absorber and the buffer layers. With conventional CdS as a buffer layer, having a fixed bandgap, tuning the band alignment is impossible. To overcome this issue, Cd-free zinc oxide-based compounds Zn(O1-xSx), Zn1-xSnxO, and Zn1-xMgxO are explored as buffer layers, and their performance is evaluated. Using their composition-dependent tunable bandgap as an advantage, suitable band alignment with the absorber layer is evaluated for equal or higher performance when compared to CdS. Further performance improvement is attempted by using SnSe as the back surface field (BSF) layer. Band alignment evaluation is also extended to the back contact (Mo)/SnSe interface, whereby an attempt is made to replace Mo with a suitable metal. The Ni is found as a good candidate to replace Mo to achieve high-efficiency solar cell. The same approach is repeated with the transparent conducting oxide layer, and aluminum doped zinc oxide (AZO) is found as a suitable material in place of ITO for optimized solar cell structure. A maximum power conversion efficiency of 17.55% is achieved with an optimized structure. It is also observed that the external quantum efficiency (EQE) of the solar cell is improved significantly in the blue photons region in comparison to the EQE of the champion solar cell. The optimized structure Ni/SnSe/CZT(S0.4Se0.6)/Zn(O0.3S0.7)/i-ZnO/AZO in this work will be very useful to fabricate low-cost and Cd-free high-efficiency kesterite solar cells. © 2021Item Exergoeconomic Optimization of Low Temperature Solar Driven Organic Rankine Cycle(Pleiades journals, 2021) Upadhyaya, S.; Gumtapure, V.Abstract: One of the most promising technologies in the field of distributed energy is the use of installations operating on the so-called organic Rankine cycle (ORC). The ORC technology is applicable for the utilization of low-potential thermal energy of natural or man-made origin. At the same time, in each specific case of using ORC systems, it is important to carry out technical and economic optimization of the project. In this paper, it is proposed to estimate the cost of electricity production by an ORC power unit using an exergoeconomical model. To optimize the system parameters in order to minimize the electricity cost rate, the method of a genetic algorithm is used. The paper presents the results of optimization of the parameters of the ORC system, which includes a solar collector in combination with an ORC power unit. R245fa is used as the working fluid in this analysis. With the help of a mathematical model, the electricity cost is calculated by comparing the costs for each of the components of the ORC system. For a given operating range of parameters of an ORC power unit with an electric capacity of 1.03 kW, a minimum cost rate of $0.056/(kW h) is determined. The optimal parameters of the working fluid in the ORC power unit, at which the minimum electricity cost can be obtained, are also determined. © 2021, Pleiades Publishing, Inc.Item Reliability, availability and maintainability (RAM) investigation of Load Haul Dumpers (LHDs): a case study(Springer, 2022) Balaraju, B.; Raj, G.R.; Murthy, S.M.Load Haul Dumpers (LHDs) are prominent equipment employed for transportation operations in many of the underground mines. This equipment often suffers from frequent breakdowns due to a variety of technical and managerial practices resulting in increased maintenance costs and loss of production and productivity. Reliability, Availability and Maintainability (RAM) analysis deal with the optimal functioning of equipment, maintenance scheduling, controlling cost, and improvement of availability and performance. Keeping this in view, the current study focused on the estimation of the performance of the equipment using RAM investigation. The required failure and repair data of LHDs were collected from field investigations. Graphical analyses using Trend and serial correlation tests and analytical analysis using Statistic-U test were conducted to validate the Independent and Identical Distribution (IID) nature of the data sets. Based on the above tests, the Renewal Process was adopted to carry out the RAM analysis. The best-fit approximation of datasets was selected by performing the Kolmogorov–Smirnov (K–S) test. In addition to that, the reliability-based Preventive Maintenance time intervals were estimated to improve the percentage of reliability. © 2021, The Society for Reliability Engineering, Quality and Operations Management (SREQOM), India and The Division of Operation and Maintenance, Lulea University of Technology, Sweden.