Geometric Tracking Control of a Multi-rotor UAV for Partially Known Trajectories

This paper presents a trajectory-tracking controller for multi-rotor unmanned aerial vehicles (UAVs) in scenarios where only the desired position and heading are known without the higher-order derivatives. The proposed solution modifies the state-of-the-art geometric controller, effectively addressing challenges related to the non-existence of the desired attitude and ensuring positive total thrust input for all time. We tackle the additional challenge of the non-availability of the higher derivatives of the trajectory by introducing novel nonlinear filter structures. We formalize theoretically the effect of these filter structures on the system error dynamics. Subsequently, through a rigorous theoretical analysis, we demonstrate that the proposed controller leads to uniformly ultimately bounded system error dynamics

Morphometry of the Dugong Dugon (Muller, 1776) skeleton based on Indian Museum specimens, Kolkata, India

817-821The present study discussed about detailed examination of skeleton characters of four dugong specimens received from Indian Museum. The specimens were deposited and preserved in the National Zoological Collection (ZSI/27608; ZSI/27609; ZSI/27610; ZSI/27611) of The Mammal and Osteological Section, Zoological Survey of India, Kolkata

New record of Melithaea retifera (Lamarck, 1816) from Andaman and Nicobar Island, India

1516-1520Alcyoniidae octocorals are represented by 405 species in India of which 154 are from Andaman and Nicobar Islands. Surveys conducted in Havelock Island, South Andaman and Shark Island, North Andaman revealed the occurrence of Melithaea retifera and is reported herein as a new distributional record to Andaman and Nicobar Islands. This species is characterised by the clubs of the coenenchyme of the node and internodes and looks like a flower-bud. The structural variations and length of sclerites in the samples are also reported in this manuscript

Occurrence of black corals (order: Antipatharian) in Andaman and Nicobar Island, India

99-107A total of 15 species of antipatharians were accounted from the study sites. Maximum number of species was reported in Henry Lawrence Island and minimum in Paget Island, Rowe Island and North Reef Island. The present study yielded seven species (Cupressopathes abies, C. pumila, Tanacetipathes hirta, Antipathes dendrochristos, Cladopathes plumose, Trissopathes tetracrada, Dendrobathypathes boutillieri) and all are first report to India

Diversity and distribution of shallow water octocorallia from Mahatma Gandhi Marine National Park, South Andaman, India

1567-1575Diversity and distribution of octocorals of Mahatma Gandhi Marine National Park (MGMNP), South Andaman were investigated from June, 2013 to May, 2016 using a Line Intercept Transect method with help of SCUBA diving. The study was carried out in 11 different islands named as Alexandra, Belle, Chester, Snob, Grub, Jolly Bouy, Boat, Red Skin Rutland, Tarmugli and Twins Islands. We undertook a systematic study on the diversity of octocorals. Thirty five species belonging to 29 genera were reported from MGMNP of which, the alcyonacea was a dominant group followed by gorgonacea, helioporacea and pennatulacea at all the study sites which is also substantiated by Principal Component analysis, and Ternary plot. Results on Bray-Curtis cluster analysis showed 35 % to 76 % similarity between the study sites in MGMNP

Occurrence of Portuguese man-of war along Digha coast, West Bengal: a threat to tourists and fisherfolk

96-98Physalia physalis belongs to the phylum Cnidaria and class Hydrozoans. It’s commonly called blue bubbles and mimic like jelly fish. In the present study, we observed the presence of floating P. Physalis from the Digha coast of West Bengal during the summer time of 2017. The occurrences and distribution of the organism were recorded in different sizes in three different sites (Old Digha, New Digha, Udaipur beach) during summer season