Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Due to advancement in technology, a huge volume of data is generated. Extracting knowledgeable data from this voluminous information is a difficult task. Therefore, machine learning techniques like classification, clustering, information retrieval, feature selection and data analysis has become core of recent research. These techniques can also be solved using Nature Inspired Algorithms. Nature Inspired Algorithms is inspired by processes, observed from nature. Feature Selection is helpful in finding subset of prominent components to enhance prescient precision and to expel the excess features. This chapter surveys seven nature inspired algorithms, namely Particle Swarm Optimization, Ant Colony Optimization Algorithms, Artificial Bees Colony Algorithms, Firefly Algorithms, Bat Algorithms, Cuckoo Search and Genetic Algorithms and its application in feature selections. The significance of this chapter is to present comprehensive review of nature inspired algorithms to be applied in feature selections.

Department of Database Systems

School of Computer Science and Engineering

Vellore Campus

Department of Structural and Geotechical Engineering

School of Civil Engineering

Advances in Computational Intelligence and Robotics Handbook of Research on Modeling, Analysis, and Application of Nature-Inspired Metaheuristic Algorithms

A Comprehensive Review of Nature-Inspired Algorithms for Feature Selection

Hydrodynamic response characteristics of classic and other Spar geometries have been investigated in the past using experimental and numerical studies in regular waves. The response of such floating system in regular waves has been reasonably established. However, in real sea condition, the existence of multiple wave frequencies in a sea state may alter the response, when the excitation frequency has the component of resonant frequency of the hull. The wave energy at the resonant frequency of the design wave spectrum is generally small, but may lead to large motion like Mathieu-type instability caused by the heave–pitch coupling effects, when the pitch/heave natural frequency ratios are critical (0.5, 1.0, 2.0, etc.). Various alternatives to reduce the heave motion of the Spar platform such as decreasing the water plane area, increasing the draft, added mass and/or damping have been in the fore front of recent research. Buoy form Spar proposed in this paper has a reduced diameter near the water plane. The motion response of such Spar in regular waves has been presented in another paper published in this journal; the heave response under random waves is presented in this paper. A classic Spar, with constant hull cross section diameter of 31 m and buoy form Spars with reduced water plane diameter of 25 and 20 m with draft of 12.5 m and displacement of 63,200 tons were considered for the study. The experimental and numerical investigations were conducted on 1:100 scale models. The pitch/heave natural frequency ratios of CLS-31, BFS-25 and BFS-20 Spars are 0.5, 0.667 and 1.0, respectively. CLS-31 and BFS-20 are vulnerable to Mathieu-type instability, since their pitch/heave natural frequency ratios are 0.5 and 1.0. Based on the study, it is concluded that the reduction in water plane area reduces the response in random waves and reduces the susceptibility to Mathieu instability. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

World University root node

Ships and Offshore Structures

Experimental and numerical investigation on hydrodynamic response of buoy form Spar under random waves

Fulltext

Indian Journal of Science and Technology

Small Disturbance Stability Assessment in Power Grids with Wind Generators

Spar platforms have been used for oil and gas exploration in deep water for the past two decades. Spar experience low heave and pitch motions in operating conditions with its deep draft and large inertia. The heave motions can be large when encountered by long period swells. These resonant response leads to unstable motions due to heave-pitch coupling in spar platforms when the heave/pitch natural period ratio is 0.5, 1.0, 1.5 and 2.0, referred to as Mathieu-type instability. This instability can be avoided by changing heave or pitch natural periods, so that the heave-pitch coupling can be avoided. The buoy form Spar proposed in this study is a cylindrical hull with curved surface near the water plane. A classic Spar of 31 m diameter and deep draft buoy form Spars with 25 m and 20 m diameter at the water plane area have been considered. The moon pool diameter of 12.5 m and the displacement of 63000 tonnes are maintained for all Spars. The experimental investigations are conducted using 1:100 scale models in the wave flume. Numerical simulations have been carried out using panel method. The classic Spar experiences Mathieu-type instability, since the heave/pitch natural period ratio is 0.5. The heave natural period of the buoy form Spar is higher than the classic Spar by 24% and 72%. The heave/pitch natural period ratio of the first buoy form Spar with 25 m diameter at the water plane area is 0.667; hence the heave-pitch coupling is avoided. The second buoy form Spar with 20 m diameter at the water plane area does not experience Mathieu-type instability, even though the heave/pitch natural period ratio is 1.0. Also the heave natural period of the second buoy form Spar is 36s (3.6 s in scale model) which is much above the design wave period. The possibility of Mathieu-type instability is avoided in the Spar by varying the hull shape near the water plane. © 2016 by ASME.

Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE

Experimental and numerical investigation on the effect of varying hull shape near the water plane on the mathieu-type instability of spar