National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Computer science. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

CAD-Based Automatic Clash Analysis for Robotic Assembly

Abstract: Assembly operation occupies major stake in the manufacturing process to obtain the final product. In order to obtain an assembly sequence for a given product, the product should be free of clashes between the parts. To know the clash between the parts, many researchers are followed mathematical models to generate contact data information of the product. These methods will consume much time and search space to extract the information from the product. Current research focuses on developing an automatic algorithm to generate the clash analysis report using macros CATIA V5 R17. In this method, it will not only generate the clash analysis report but also generate a contact information matrix between the parts of the assembly. The developed methodology is implemented on various industrial products to extract the clash information of the product.

Analysis of three-dimensional transient seepage into ditch drains from a ponded field

Abstract: An analytical solution in the form of infinite series is developed for predicting time-dependent three-dimensional seepage into ditch drains from a flat, homogeneous and anisotropic ponded field of finite size, the field being assumed to be surrounded on all its vertical faces by ditch drains with unequal water level heights in them. It is also assumed that the field is being underlain by a horizontal impervious barrier at a finite distance from the surface of the soil and that all the ditches are being dug all the way up to this barrier. The solution can account for a variable ponding distribution at the surface of the field. The correctness of the proposed solution for a few simplified situations is tested by comparing predictions obtained from it with the corresponding values attained from the analytical and experimental works of others. Further, a numerical check on it is also performed using the Processing MODFLOW environment. It is noticed that considerable improvement on the uniformity of the distribution of the flow lines in a three-dimensional ponded drainage space can be achieved by suitably altering the ponding distribution at the surface of the soil. As the developed three-dimensional ditch drainage model is pretty general in nature and includes most of the common variables of a ditch drainage system, it is hoped that the drainage designs based on it for reclaiming salt-affected and water-logged soils would prove to be more efficient and cost-effective as compared with designs based on solutions developed by making use of more restrictive assumptions. Also, as the developed model can handle three-dimensional flow situations, it is expected to provide reliable and realistic drainage solutions to real field situations than models being developed utilizing the two-dimensional flow assumption. This is because the existing two-dimensional solutions to the problem are actually valid not for a field of finite size but for an infinite one only.

Phase-locked Loop (PLL) Based Phase Estimation in Single Channel Speech Enhancement.

Abstract: Conventional speech enhancement techniques are based on the modification of noisy spectral magnitude. In the reconstruction of the enhanced signal, noisy phase is combined with the modified noisy spectral magnitude. Recent studies on the importance of phase in enhancement process shows that the clean speech phase improves the quality of the enhanced signal. This work focused on Phase-Locked Loop (PLL) based time-domain approach for estimating the clean speech phase from noisy speech signal. The proposed technique is compared with the conventional approaches where noisy phase is used in the reconstruction of the enhanced signal. Here, Log-Likelihood Ratio (LLR), Weighted Spectral Slope (WSS) distance and Perceptual Evaluation of Speech Quality (PESQ) are used as performance measures. From experimental results, it is observed that the speech quality and intelligibility improved significantly with the proposed method over existing methods.

Cuckoo search algorithm based two degree of freedom controller for multi-area thermal system

Abstract: Two-degree-of-freedom based Proportional plus Integral plus Double Derivative (2-DOF-PIDD) controller is designed and presented to solve the load frequency control (LFC) problem of a three unequal area thermal system. All the areas are equipped with single stage of reheat turbines and appropriate generation rate constraints (GRC). The performances of the proposed 2-DOF-PIDD controller are compared with the commonly used classical controllers such as I, PI and PID controller to assess the best supplementary controller for LFC. Selection of the optimum parameter of the several controllers and speed regulation (R) parameters are done by a new metaheuristic optimization algorithm called Cuckoo Search algorithm (CSA). The main advantage associated with CSA is that it has only two controllable parameters that make the algorithm less complex and thus potentially more generic. Numerous simulation results clearly show that proposed controller guarantees better performance over others in terms of settling time, peak overshoots and reduced oscillations. Further, robustness of CSA optimized 2-DOF-PIDD controller is tested against different position of perturbation. Proposed 2-DOF-PIDD controller also provides better performances when subjected to higher degree of perturbation.