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 & Electric power system. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

Game-Theoretic Strategic Coordination and Navigation of Multiple Wheeled Robots

Abstract: Multiple robots negotiating in a dynamic workspace may lead to collisions. To avoid such issues, multi-robot navigation and coordination becomes necessary but is computationally very challenging, particularly when there are many robots. This article addresses the problem of multi-robot navigation where individual robots require coordination. Although a few such attempts for modeling multi-robot coordination and navigation have been studied, this work proposes a game-theoretic coordination strategy, also referred to as strategic coordination. We make use of a genetic algorithm tuned fuzzy logic–based motion planner. The proposed strategic coordination strategy has been pitted against a basic potential field-based motion planner, also referred to as the heuristic method, for performance comparison. Results are compared through computer simulation with 8 to 17 robots at different rounds. From the obtained results, it was observed that the proposed coordination scheme’s efficacy is strong for a larger number of robots. In addition, the proposed strategic coordination scheme with the genetic-fuzzy-based motion planner was found to outperform other combinations as far as the quality of solutions and time to reach the goal positions. The computational complexity of different methods has also been compared and presented.

Identifying Bengali Multiword Expressions using semantic clustering

Abstract: One of the key issues in both natural language understanding and generation is the appropriate processing of Multiword Expressions (MWEs). MWEs pose a huge problem to the precise language processing due to their idiosyncratic nature and diversity in lexical, syntactical and semantic properties. The semantics of a MWE cannot be expressed after combining the semantics of its constituents. Therefore, the formalism of semantic clustering is often viewed as an instrument for extracting MWEs especially for resource constraint languages like Bengali. The present semantic clustering approach contributes to locate clusters of the synonymous noun tokens present in the document. These clusters in turn help measure the similarity between the constituent words of a potentially candidate phrase using a vector space model and judge the suitability of this phrase to be a MWE. In this experiment, we apply the semantic clustering approach for noun-noun bigram MWEs, though it can be extended to any types of MWEs. In parallel, the well known statistical models, namely Point-wise Mutual Information (PMI), Log Likelihood Ratio (LLR), Significance function are also employed to extract MWEs from the Bengali corpus. The comparative evaluation shows that the semantic clustering approach outperforms all other competing statistical models. As a byproduct of this experiment, we have started developing a standard lexicon in Bengali that serves as a productive Bengali linguistic thesaurus.

Differential Cross Sections and Product Rovibrational Distributions for (16)O + (32)O2 and (18)O + (36)O2 Collisions.

Abstract: We report rotationally resolved opacity functions, product rotational distributions, and differential cross sections for the (16)O + (16)O(16)O (v = 0,j = 1) → (16)O(16)O (v' = 0,j') + (16)O and (18)O + (18)O(18)O (v = 0,j = 1) → (18)O(18)O (v' = 0,j') + (18)O collisions calculated by a time-independent quantum mechanical method employing one of the latest potential energy surface of ozone [ Dawes ; et al. J. Chem. Phys. 2013 , 139 , 201103 ]. The results obtained for both collisional systems in the energy range 0.001-0.2 eV are examined, and interesting mass scaling effects have been discovered. The shapes of product angular distributions suggest a transition from an indirect to a direct scattering, via an osculating intermediate complex.

Effect of Considering Secondary Parts as Primary Parts for Robotic Assembly Using Stability Graph

Abstract: Robotic assembly sequence generation requires many assembly predicates to generate optimal assembly sequences. Achieving such optimal assembly sequences is difficult as it requires huge search space. In the past literature, most of the researchers try to reduce the search space of assembly sequence planning problem by applying different methods such as computer-aided design-based methods, knowledge-based methods and artificial intelligence-based methods in terms of execution time and number of iterations by considering secondary parts (nuts, bolts, washers, fits, etc.). In this paper, stability graph concept has been introduced to represent the secondary part information for generating optimal assembly sequences. A comparison has been made without fruit fly in terms of execution time and number of iterations while generating optimal assembly sequences with and without consideration of secondary parts as primary parts. To check the effectiveness of the proposed method, three different industrial products with eight parts, 19 parts and 22 parts are considered for generating optimal assembly sequences.

Design of a Compact ROV for River Exploration

Abstract: Remotely operated underwater vehicles (ROVs) are being extensively used in marine industry for exploration, pollution control, and military applications. With time ROVs have become smaller, less expensive, reliable and practical for small scale use. This paper presents the design of a compact low-cost ROV for river exploration with a modular structure. The ROV is neutrally buoyant which increases its efficiency. The ROV uses three thrusters for its movement inside water and has 3 degrees of freedom (DOF). A detailed 3D model is developed using SOLIDWORKS and stress analysis has been carried out to ensure it will not fail under hydrodynamic pressure. Hydrodynamic characteristics are studied using ANSYS FLUENT, which helps in determining the maximum thrust required for the vehicle propulsion and the maximum achievable velocity. The prototype is manufactured with glass fiber composite and fitted with different electronics components, sensors, and battery. The field test of the ROV is carried out in a controlled underwater environment.