National Institute of Technology Meghalaya
Meghalaya, India

National Institute of Technology Meghalaya also known as NIT Meghalaya or NITM is one of the 30 National Institutes of Technology situated in Shillong, Meghalaya, India. The classes of NIT Meghalaya were started in 2010 at the Sardar Vallabhbhai National Institute of Technology, Surat. Wikipedia.

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Pinto S.J.,National Institute of Technology Meghalaya | Panda G.,National Institute of Technology Meghalaya
IEEE Region 10 Annual International Conference, Proceedings/TENCON | Year: 2017

In this paper, a novel detection technique using Fractional Wavelet Transform (FRWT) is applied for monitoring three-phase grid connected PV generation system. The idea behind this protection scheme is based on combined features derived from Discrete Fractional Fourier Transform (DFRFT) and Discrete Wavelet Transform (DWT) techniques, which provides more actual time-frequency information. In this study, DFRFT is applied for the fast recognition of a transformed signal via fractional rotation in time-frequency plane and DWT is applied for detecting power disruption in the system more accurately. The effectiveness of applied hybrid technique is also compared with Wavelet Transform (WT) by simulating the system in MATLAB/SIMULINK environment. The simulated results demonstrate the feasibility and effectiveness of the proposed detection strategy under noisy situation and also in the existence of harmonics. © 2016 IEEE.

Bose T.,National Institute of Technology Meghalaya | Mohanty A.R.,Indian Institute of Technology Kharagpur
International Journal of Mechanical Sciences | Year: 2017

Here, the large amplitude axisymmetric vibration of a circular plate having a circumferential crack is studied considering the simply supported and clamped boundary conditions. Exact modal functions are generated by satisfying the boundary conditions and constraints along the crack. The inplane or membrane forces resulting from the large deflection are derived from the Berger's formulation. Next, the Galerkin's method is used to transform the differential equation into the Duffing equation with cubic nonlinearities. The amplitude and phase curves are generated using the Method of multiple scales. Natural frequency variations of axisymmetric modes are studied for a change in crack depth and crack position, considering both boundary conditions. Some natural frequencies are also compared with the finite element results and they are found to be in good agreement. For clamped boundary conditions, the natural frequency of a cracked plate is shown to approach that of an uncracked plate for a particular crack position independent of different crack depths. The amplitude and phase curves are shown for different crack parameters. Finally, the phase plane plot variations are presented for different crack depths, positions and boundary conditions. © 2017

Poria S.,Jadavpur University | Gelbukh A.,National Polytechnic Institute of Mexico | Hussain A.,University of Stirling | Howard N.,Massachusetts Institute of Technology | And 2 more authors.
IEEE Intelligent Systems | Year: 2013

A methodology to automatically assign emotion labels to SenticNet concepts is proposed. SenticNet was supplied with affective WordNet-Affect (WNA) compatible labels using a machine learning algorithm. The WNA list dataset consists of six word lists corresponding to Ekman's six basic emotions, anger, disgust, fear, joy, sadness, and surprise. The dataset contains 606 synsets, of which all but two are assigned exactly one label each. If the synsets are broken down into individual concepts, the dataset contains 1,536 concepts. For each SenticNet concept, ISEAR statistical features of its occurrences and cooccurrences with other SenticNet concepts in ISEAR statements were extracted. English WordNet 3.0 was used to measure the semantic distance between two words. This work opens up multiple directions for future research, such as using other types of monolingual or multilingual corpora as a source of features to improve the accuracy or to label more concepts.

Pinto S.J.,National Institute of Technology Meghalaya | Panda G.,National Institute of Technology Meghalaya
International Journal of Electrical Power and Energy Systems | Year: 2016

Recent developments in power electronics technology have emerged towards the generation of electrical power from the renewable energy sources. Among renewable energy sources, solar energy has garnered more importance because of less maintenance and environmental friendly. In grid connected mode, distributed power generation system (DPGS) requires reliable islanding detection technique to find the electrical grid status and operate the grid connected inverter effectively. This paper investigates a comparative performance analysis of wavelet transform (WT) and wavelet packet transform (WPT) based detection in a three-phase grid connected PV inverter system under various power quality disturbances and islanding situation. The WT and WPT coefficients are determined by applying db4 wavelet basis functions, which are obtained optimally for analyzing perturbations that occur in grid connected PV system. The wavelet transform produces large errors due to spectral leakages in frequency bands. On the other hand, WPT provides uniform frequency subband with better time frequency resolution over WT. Finally, the feasibility of proposed WPT based islanding detection method is verified by simulating the system in MATLAB/SIMULINK environment. The simulated results demonstrate the better performance of WPT over WT technique and proved as an accurate, fast and reliable detection technique. © 2015 Elsevier Ltd. All rights reserved.

Kalita H.M.,National Institute of Technology Meghalaya
Water Resources Management | Year: 2016

This paper presents a new efficient and robust hydrodynamic model for simulation of unsteady shallow water flow. The governing equations of shallow water flows in two dimensional forms are solved using a new total variation diminishing (TVD) MacCormack predictor corrector scheme. In this numerical technique an additional TVD term is added after the traditional predictor corrector steps. The advantage of the present TVD term is that it is very simple and gives accurate results at the same time removing the numerical oscillations. Further, application of semi implicit treatment of the friction slope term helps in flow simulation even with very low water depth. Finally the model is used to analyze a wide variety of hydraulic problems including quiescent water above irregular bed, steady flow over irregular bed, steady flow over irregular bed with a shock, dam break flow over dry bed and dam break flow over wet bed. For each of the cases numerical results are compared with available analytical solution and known experimental data. The agreements between the results are satisfactory. © 2016 Springer Science+Business Media Dordrecht

Das D.,National Institute of Technology Meghalaya
2015 International Conference on Electronic Design, Computer Networks and Automated Verification, EDCAV 2015 | Year: 2015

The paper describes the work on human gait recognition using Hidden Markov Model (HMM), Support Vector Machine (SVM) and Hybridized classifiers (developed using both HMM and SVM). Human gait data obtained from CASIA gait database were segmented to locate major human body part and generate corresponding stick view in order to extract gait features. A total of 25 features were obtained using the length of body parts and major joint angles along with other features and classified using HMM, SVM and Hybridized classifiers. The Hybridized classifier outperforms individual classifiers by 11.25% and 18.14% during training and testing respectively. © 2015 IEEE.

Paul P.,Indian Institute of Science | Ghosh B.,National Institute of Technology Meghalaya | Kar T.K.,Indian Institute of Science
Communications in Nonlinear Science and Numerical Simulation | Year: 2015

In the present article, we consider two food chain models with three trophic levels: one is 'prey-predator-top predator' system where the top-predator consumes only the predator trophic level and the another one is 'prey-predator-generalist predator' system where the generalist-predator (top trophic level) consumes both the predator and the prey species. We examine the impacts of different levels of nutrient supply to the bottom species (prey) in both the models. We derive conditions when additional nutrient supply cannot bring the top trophic level to coexist in both the systems if the top trophic level is absent prior to nutrient supply. Once the three trophic levels are present prior to an additional nutrient supply, biomass of the predator trophic level reduces or even the predator trophic level goes to extinction in the 'prey-predator-generalist predator' system due to a massive amount of nutrient supply. We also explore the impacts of fishing mortality to achieve maximum sustainable yield (MSY) from individual trophic level. The most important conclusion is that harvesting the predator at MSY level is a sustainable fishing policy in 'prey-predator-generalist predator' system. © 2015 Elsevier B.V.

Marthong C.,National Institute of Technology Meghalaya | Sarma D.K.,National Institute of Technology Meghalaya
European Journal of Environmental and Civil Engineering | Year: 2015

Polyethylene terephthalate (PET) fibers are generally used as a discrete reinforcement in the substitution of steel fiber for enhancing the tensile strength as well as improving the ductile property of concrete. PET fibers can be produced by hand cutting from PET bottles or through mechanical slitting. Straight slit sheet fibers obtained from the former process normally result in a weak bond with the concrete matrix and they can slip out at low loads. To improve the anchorage effect, three additional PET fibers with varying geometry (flattened end slit sheet, deformed slit sheet and crimped end sheet) were considered in the present study. The influence of fiber geometry on the mechanical properties of cylindrical and prismatic concrete specimens was investigated. The test results show that the fibers’ geometry has a marginal effect on the workability of concrete but a significant contribution to the mechanical properties of concrete. © 2015 Taylor & Francis

Debbarma S.,National Institute of Technology Meghalaya | Chandra Saikia L.,National Institute of Technology Silchar | Sinha N.,National Institute of Technology Silchar
ISA Transactions | Year: 2014

Present work focused on automatic generation control (AGC) of a three unequal area thermal systems considering reheat turbines and appropriate generation rate constraints (GRC). A fractional order (FO) controller named as IλDμ controller based on crone approximation is proposed for the first time as an appropriate technique to solve the multi-area AGC problem in power systems. A recently developed metaheuristic algorithm known as firefly algorithm (FA) is used for the simultaneous optimization of the gains and other parameters such as order of integrator (λ) and differentiator (μ) of IλDμ controller and governor speed regulation parameters (R). The dynamic responses corresponding to optimized IλDμ controller gains, λ, μ, and R are compared with that of classical integer order (IO) controllers such as I, PI and PID controllers. Simulation results show that the proposed IλDμ controller provides more improved dynamic responses and outperforms the IO based classical controllers. Further, sensitivity analysis confirms the robustness of the so optimized I λDμ controller to wide changes in system loading conditions and size and position of SLP. Proposed controller is also found to have performed well as compared to IO based controllers when SLP takes place simultaneously in any two areas or all the areas. Robustness of the proposed IλDμ controller is also tested against system parameter variations. © 2013 ISA.

Debbarma S.,National Institute of Technology Meghalaya | Saikia L.C.,National Institute of Technology Silchar | Sinha N.,National Institute of Technology Silchar
International Journal of Electrical Power and Energy Systems | Year: 2014

In this paper, Two-Degree-of-Freedom-Fractional Order PID (2-DOF-FOPID) controller is proposed for automatic generation control (AGC) of power systems. Proposed controller is tested for the first time on a three unequal area thermal systems considering reheat turbines and appropriate generation rate constraints (GRCs). The simultaneous optimization of several parameters of the controllers and speed regulation parameter (R) of the governors is done by a recently developed metaheuristic nature-inspired algorithm known as Firefly Algorithm (FA). Investigation clearly reveals the superiority of the 2-DOF-FOPID controller in terms of settling time and reduced oscillations. Present work also explores the effectiveness of the Firefly algorithm based optimization technique in finding the optimal parameters of the controller and selection of R parameter. Further, the convergence characteristics of the FA are compared to justify its efficiency with other well established optimization technique such as PSO, BFO and ABC. Sensitivity analysis confirms the robustness of the 2-DOF-FOPID controller for different loading conditions and wide changes in inertia constant (H) parameter. Furthermore, the performance of proposed controller is tested against higher degree of perturbation and random load pattern. © 2014 Elsevier Ltd. All rights reserved.

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