Consensus of Multi-Agent Networks in the Presence of Adversaries Using Only Local Information

This paper addresses the problem of resilient consensus in the presence of misbehaving nodes. Although it is typical to assume knowledge of at least some nonlocal information when studying secure and fault-tolerant consensus algorithms, this assumption is not suitable for large-scale dynamic networks. To remedy this, we emphasize the use of local strategies to deal with resilience to security breaches. We study a consensus protocol that uses only local information and we consider worst-case security breaches, where the compromised nodes have full knowledge of the network and the intentions of the other nodes. We provide necessary and sufficient conditions for the normal nodes to reach consensus despite the influence of the malicious nodes under different threat assumptions. These conditions are stated in terms of a novel graph-theoretic property referred to as network robustness.Comment: This report contains the proofs of the results presented at HiCoNS 201

Asymmetric phase-transfer-catalyzed synthesis of five-membered cyclic gamma-Amino acid precursors

The first example of an intramolecular enantioselective Michael addition of nitronates onto conjugated systems utilizing a chiral phase-transfer catalyst is described. A range of five-membered gamma-nitro esters with up to three stereocentres have been prepared and the relative and absolute configurations proven by chemical and crystallographic methods. The products are rapidly obtained and are precursors to five-membered cyclic gamma-amino acids

A Slicing Procedure for 5-Axis layered Manufacturing

The 5-axis layered manufacturing technology facilitates fabrication of a part with overhanging features without the use of supports, thereby making a direct-to-use part from the layered manufacturing technology a reality. In this paper we describe a direct slicing procedure for a CAD model, a crucial process planning task for the 5-axis layered manufacturing. The neutral exchange format IGES is used as the slice format. The G and M codes for a CNC 5-axis laser deposition machine are generated from the slice format and the deposition process is simulated. Implemented examples are included to explain the slicing procedure. Exciting possibilities for the future work on the slicing procedure are discussed.Mechanical Engineerin

Spanning trees short or small

We study the problem of finding small trees. Classical network design problems are considered with the additional constraint that only a specified number $k$ of nodes are required to be connected in the solution. A prototypical example is the $k$MST problem in which we require a tree of minimum weight spanning at least $k$ nodes in an edge-weighted graph. We show that the $k$MST problem is NP-hard even for points in the Euclidean plane. We provide approximation algorithms with performance ratio $2\sqrt{k}$ for the general edge-weighted case and $O(k^{1/4})$ for the case of points in the plane. Polynomial-time exact solutions are also presented for the class of decomposable graphs which includes trees, series-parallel graphs, and bounded bandwidth graphs, and for points on the boundary of a convex region in the Euclidean plane. We also investigate the problem of finding short trees, and more generally, that of finding networks with minimum diameter. A simple technique is used to provide a polynomial-time solution for finding $k$-trees of minimum diameter. We identify easy and hard problems arising in finding short networks using a framework due to T. C. Hu.Comment: 27 page

Occurrence of Octopus vulgaris Cuvier, 1797 at Mumbai, Maharashtra

Octopuses popularly called as ‘devilfish’ are caught mainly as bycatch in the bottom trawl. Due to the growing demand for octopus in the international market, octopus fishery is catching up in Maharashtra. The main fish landing centres for octopus in Mumbai are New Ferry Wharf and Sassoon Dock. Octopuses contribute 3.6% towards the total cephalopod catch in Mumbai. Ommen (1971, 1977) identified many new species of octopus along the west coast of India

Octopus landing at Mumbai Fishing harbour, New Ferry Wharf

Octopuses in the continental shelf and oceanic region are caught mainly as by catch in the bottom trawl and the major genera are Octopus, Cistopus and Eledone.The three main species which constitute the fishery of Mumbai are Octopus dollfusi, Cistopus indicus and Octopus membranaceous.They are processed and sold in local market

Record of Loliolus investigatoris (Goodrich, 1886),Loliginid squid, Doryteuthis singhalensis (Ortmann, 1891) and Onychoteuthis baski (Leach, 1817) occurring off Mumbai waters

Expansion of fishing areas reported new records of cephalopods were reported from various places all along the coast.The species is processed and exported wholly as ‘baby squids’ alongwith the catch of juveniles of Loligo duvaceli.Loliolus investigatoris (Goodrich, 1886) (Fig.1) occur infrequently in trawl catches.Onychoteuthis baski was also reported which was earlier reported in Andamans and Nicobar islands on a cruise of FORV Sagar Sampada