National Institute of Technology Calicut

About: National Institute of Technology Calicut is a education organization based out in Kozhikode, Kerala, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 3627 authors who have published 4638 publications receiving 50830 citations. The organization is also known as: Calicut Regional Engineering College & NIT Calicut.

Stability analysis of interval time-varying delayed neural networks including neutral time-delay and leakage delay

Abstract: This paper addresses an improved stability criterion for an interval time-delayed neural networks (NNs) including neutral delay and leakage delay. By proposing a suitable Lyapunov–Krasovskii functionals (LKFs) together with the Auxiliary function-based integral inequality (AFBII) and reciprocally convex approach (RCC) approach. The major purpose of this research is put forward to the consideration of inequality techniques together with a suitable LKFs, and mixed with the Leibniz–Newton formula within the structure of linear matrix inequalities (LMIs). It is amazing that, the leakage delay has a disrupting impact on the stability behaviour of such system and they cannot be neglected. Finally, numerical examples have been demonstrated to showing feasibility and applicability of the developed technique. In addition, the developed stability criteria tested for feasibility of the benchmark problem to explore the real-world application in the sense of discrete time-delay and leakage delay as a process variable in the system model.

Application of Cole–Cole model to transformer oil-paper insulation considering distributed dielectric relaxation

Abstract: Researchers have been exploring dielectric testing techniques both in time and frequency domain for insulation condition assessment of oil-paper insulated transformers. In a practical dielectric system, dipoles are found to behave according to a distribution of elementary Debye relaxation properties. Suitable distribution density functions have been proposed to characterise such many-body interaction processes. Cole–Cole diagrams can be one of the methods for studying the nature of frequency dependency of dielectric materials of complex structure. Cole–Cole plots are commonly used for characterising different materials such as dielectric mixtures, ionic liquids, cable insulating oil, polar liquids etc. The scope of its application for assessing transformer oil-paper insulation considering distributed relaxation process has not been explored yet. The present contribution discusses mathematical formulations used for transforming the experimentally obtained time domain dielectric response test data to distribution domain and further to frequency domain for obtaining the Cole–Cole plots. Findings about the influence of various operating conditions and insulation status on the Cole–Cole diagram have been reported in this contribution. Results of tests on field transformers are also presented. This paper attempts to employ the features of Cole–Cole diagrams as potential indicators for analysing condition of the oil-paper insulation considering distributed relaxation process.

Beating capillarity in thin film flows

Abstract: The combination of substrate unevenness and capillarity is known to induce far-reaching perturbations at the free surface of thin liquid films. These might be undesired and this paper explores the possibility to control the free surface of thin liquid films to give it a prescribed profile by a suitable design of the underlying substrate. This corresponds to the inverse of the widely studied forward problem, which considers the effect of substrate unevenness on a free surface. Assuming that the steady free surface profile can be described by the lubrication approximation, this optimal control problem is shown to be governed by a first-order partial differential equation, which is solved numerically using the method of characteristics. The proposed method is successfully tested for a range of desired free surface profiles and the domain of existence of a solution to the inverse problem is probed. Expectedly, it is shown that, owing to surface tension, not all free surface profiles can be achieved but in some cases capillarity can be beaten and a prescribed free surface profile obtained. Copyright © 2009 John Wiley & Sons, Ltd.