Modelling and Verification of Multiple UAV Mission Using SMV

Model checking has been used to verify the correctness of digital circuits, security protocols, communication protocols, as they can be modelled by means of finite state transition model. However, modelling the behaviour of hybrid systems like UAVs in a Kripke model is challenging. This work is aimed at capturing the behaviour of an UAV performing cooperative search mission into a Kripke model, so as to verify it against the temporal properties expressed in Computation Tree Logic (CTL). SMV model checker is used for the purpose of model checking

Topological Change in Mean Convex Mean Curvature Flow

Consider the mean curvature flow of an (n+1)-dimensional, compact, mean convex region in Euclidean space (or, if n<7, in a Riemannian manifold). We prove that elements of the m-th homotopy group of the complementary region can die only if there is a shrinking S^k x R^(n-k) singularity for some k less than or equal to m. We also prove that for each m from 1 to n, there is a nonempty open set of compact, mean convex regions K in R^(n+1) with smooth boundary for which the resulting mean curvature flow has a shrinking S^m x R^(n-m) singularity.Comment: 19 pages. This version includes a new section proving that certain kinds of mean curvature flow singularities persist under arbitrary small perturbations of the initial surface. Newest update (Oct 2013) fixes some bibliographic reference

Airborne mapping of complex obstacles using 2D Splinegon

This paper describes a recently proposed algorithm in mapping the unknown obstacle in a stationary environment where the obstacles are represented as curved in nature. The focus is to achieve a guaranteed performance of sensor based navigation and mapping. The guaranteed performance is quantified by explicit bounds of the position estimate of an autonomous aerial vehicle using an extended Kalman filter and to track the obstacle so as to extract the map of the obstacle. This Dubins path planning algorithm is used to provide a flyable and safe path to the vehicle to fly from one location to another. This description takes into account the fact that the vehicle is made to fly around the obstacle and hence will map the shape of the obstacle using the 2D-Splinegon technique. This splinegon technique, the most efficient and a robust way to estimate the boundary of a curved nature obstacles, can provide mathematically provable performance guarantees that are achievable in practice

Population structure of pink salmon (Oncorhynchus gorbuscha) in British Columbia and Washington, determined with microsatellites

Population structure of pink salmon (Oncorhynchus gorbuscha) from British Columbia and Washington was examined with a survey of microsatellite variation to describe the distribution of genetic variation. Variation at 16 microsatellite loci was surveyed for approximately 46,500 pink salmon sampled from 146 locations in the odd-year broodline and from 116 locations in the even-year broodline. An index of genetic differentiation, FST, over all populations and loci in the odd-year broodline was 0.005, with individual locus values ranging from 0.002 to 0.025. Population differentiation was less in the even-year broodline, with a FST value of 0.002 over all loci, and with individual locus values ranging from 0.001 to 0.005. Greater genetic diversity was observed in the odd-year broodline. Differentiation in pink salmon allele frequencies between broodlines was approximately 5.5 times greater than regional differentiation within broodlines. A regional structuring of populations was the general pattern observed, and a greater regional structure in the odd-year broodline than in the even-year broodline. The geographic distribution of microsatellite variation in populations of pink salmon likely ref lects a distribution of broodlines from separate refuges after the last glaciation period

New Approaches for Evaluating Lidar-Derived Shoreline

This study presents and compares two new methods of assessing the uncertainty of lidar-derived National Shoreline mapped by NOAA’s National Geodetic Survey: an empirical (ground-based) approach and a stochastic (Monte Carlo) approach. OCIS codes: (280.3640) Lidar; (120.2830) Height measurements; (000.4430) Numerical approximation and analysi

On-line evolutionary algorithm guidance for multiple missiles against multiple targets

This paper details the application of a Cooperative Coevolution On-Line Evolutionary Algorithm (CCOLEA) to the guidance of a swarm of multiple missiles, against multiple targets. The CCOLEA trades the spatial distribution of missiles at impact, against the cost of re-aiming the missiles' seekers onto their final targets. A parallel approach is used where each missile optimises its own performance, based on limited information from the other missiles. The decision making processis thus distributed between the missiles giving distributed coordination

Chandra Observation of the Radio Source / X-ray Gas Interaction in the Cooling Flow Cluster Abell 2052

We present a Chandra observation of Abell 2052, a cooling flow cluster with a central cD that hosts the complex radio source 3C 317. The data reveal ``holes'' in the X-ray emission that are coincident with the radio lobes. The holes are surrounded by bright ``shells'' of X-ray emission. The data are consistent with the radio source displacing and compressing, and at the same time being confined by, the X-ray gas. The compression of the X-ray shells appears to have been relatively gentle and, at most, slightly transonic. The pressure in the X-ray gas (the shells and surrounding cooler gas) is approximately an order of magnitude higher than the minimum pressure derived for the radio source, suggesting that an additional source of pressure is needed to support the radio plasma. The compression of the X-ray shells has speeded up the cooling of the shells, and optical emission line filaments are found coincident with the brightest regions of the shells.Comment: accepted for publication in ApJ Letters; for high-resolution color figures, see http://www.astro.virginia.edu/~elb6n/abell2052.htm

A Sea-Level Lowstand (Devil\u27s Point Event) Recorded in Bahamian Reefs: Comparison with Other Last Interglacial Climate Proxies

Reprinted from: Benjamin J. Greenstein and Cindy K. Carney (eds.) Proceedings of the 10th Symposium on the Geology of the Bahamas and Other Carbonate Regions: San Salvador, Gerace Research Cente

Guide to Bahamian Ichnology: Pleistocene, Holocene, and Modern Environments: A Field Trip Guide

This guide was prepared for the Fourth International Ichnofabric Workshop (IIW- 4) to be hosted by the Bahamian Field Station and held on San Salvador Island on March 15-22, 1997. About 35 scientists representing 15 countries are registered to attend the workshop. The focus of discussion in the infonnal scientific sessions will be the uses of ichnofabric analysis in sedimentary geology. An ichnofabric is the texture or internal structure created within a sedimentary substrate from the bioturbating activity of organisms. Ichnofabric analysis is a new and emerging area of ichnology (the study of trace fossils), and its methods are proving useful in enhancing sedimentary facies recognition and interpretations, event correlation, paleoenvironmental and paleoecological reconstructions, reservoir prediction, and more. Ichnologists are field oriented, and San Salvador Island, with its diverse and largely pristine modem tropical, carbonate environments and well exposed Pleistocene and Holocene rock record, provides provides a fantastic natural laboratory for the study of all aspects of carbonate geology. San Salvador also is a geologically and ichnologically well known island, so proven field localities are readily available. This doesn\u27t mean that new ichnologic discoveries and interpretations won\u27t be forthcoming - they certainly will be, and probably some will occur during the time of the IIW-4 workshop. My colleague Brian White and I have been working in the Bahamas for just over 15 years. We know a great deal about Bahamian geology, but with every field excursion we find something new, and I often think that we have just scratched the surface! The centerpiece of this guide is the descriptions of six Ichno-localities on San Salvador Island that provide outstanding examples of modem traces or trace fossils and illustrate a veriety of ichnologic principles. In addition, in composite form, the stops provide a good overview of the Pleistocene, Holocene, and modem geology and environments of San Salvador. All of the stops are readily accessible from the main roads on the island. The initial chapter provides a brief introduction to the geology of the Bahamas and San Salvador for first-time visitors. The three chapters at the end of the guide are thematic and designed to expand the ichnologic perspectives to include borer organisms, plant trace fossils, and ichnologic sites in the Bahamas beyond San Salvador. I hope this guide will be useful to a broad spectrum of visitors to the Bahamian Field Station for several years to come, as well as to ichnologists unable to attend this workshop but with an interest in carbonates. See other Smith authored Field Trip Guides of Gerace Research Centre

Bahamian Sangamonian Coral Reefs and Sea-Level Change

Reprinted from James L. Carew (ed.) May 30–June 3, 1996, Proceedings of the 8th Symposium on the Geology of the Bahamas and Other Carbonate Regions: Bahamian Field Station, San Salvador, Bahamas