18,932 research outputs found
A field guide for Agency staff operating the SIMRAD EY500 portable scientific echosounder. 2nd draft 3rd August 1999
This manual has been produced by members of the national acoustics group (NAG) and represents the first in a series of outputs designed to promote co-ordination and consistency
in Agency hydroacoustic surveys. It is designed as a field guide for Agency staff operating the SIMRAD EY500 portable scientific echosounder. It should be simplistic enough for the newcomer to EY500 to be able to set up and run a mobile hydroacoustic survey with some knowledge of the supporting theory. It should act as guidance for standardisation of survey procedures providing a concise list of settings and recommendations that can be used as a quick reference guide in the field. This manual condenses 5 years of practical experience of surveying fish populations using Simrad hardware and software for surveying large rivers and still waters throughout England and Wales. This document should be used as a companion to the manufacturers instruction manual and not act as a substitute for it
Discrete analogue computing with rotor-routers
Rotor-routing is a procedure for routing tokens through a network that can
implement certain kinds of computation. These computations are inherently
asynchronous (the order in which tokens are routed makes no difference) and
distributed (information is spread throughout the system). It is also possible
to efficiently check that a computation has been carried out correctly in less
time than the computation itself required, provided one has a certificate that
can itself be computed by the rotor-router network. Rotor-router networks can
be viewed as both discrete analogues of continuous linear systems and
deterministic analogues of stochastic processes.Comment: To appear in Chaos Special Focus Issue on Intrinsic and Designed
Computatio
Literary and theological responses to the Holocaust
SIGLEAvailable from British Library Document Supply Centre- DSC:DX86116 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Fixed versus Flexible: Lessons from EMS Order Flow
This paper addresses the puzzle of regime-dependent volatility in foreign exchange. We extend the literature in two ways. First, our microstructural model provides a qualitatively new explanation for the puzzle. Second, we test implications of our model using Europe's recent shift to rigidly fixed rates (EMS to EMU). In the model, shocks to order flow induce volatility under flexible rates because they have portfolio-balance effects on price, whereas under fixed rates the same shocks do not have portfolio-balance effects. These effects arise in one regime and not the other because the elasticity of speculative demand for foreign exchange is (endogenously) regime-dependent: low elasticity under flexible rates magnifies portfolio-balance effects; under credibly fixed rates, elasticity of speculative demand is infinite, eliminating portfolio-balance effects. New data on FF/DM transactions show that order flow had persistent effects on the exchange rate before EMU parities were announced. After announcement, determination of the FF/DM rate was decoupled from order flow, as predicted by the model.
Evaluation of Induced Sterility for Beaver (Castor canadensis) Management Problems
The concept of controlling animal damage problems by reducing fecundity of offending species through induced sterility first was proposed by Knipling (1955) for insect control and was applied successfully by that author (Knipling 1959) for eradication of the screw-worm fly. The potential application to vertebrate pest problems was recognized immediately by David (1961) and, subsequently, by many other workers for a variety of pests (e.g. Balser 1964; Kennelly et al. 1970: Murton et al. 1972; McDonald 1980; Potvin et al. 1982) including beaver (Arner 1964; Blanchard 1964; Nevers 1968; Hill 1977). Unfortunately, the method remains today largely unavailable for routine application to vertebrate pests
Hypercube matrix computation task
The Hypercube Matrix Computation (Year 1986-1987) task investigated the applicability of a parallel computing architecture to the solution of large scale electromagnetic scattering problems. Two existing electromagnetic scattering codes were selected for conversion to the Mark III Hypercube concurrent computing environment. They were selected so that the underlying numerical algorithms utilized would be different thereby providing a more thorough evaluation of the appropriateness of the parallel environment for these types of problems. The first code was a frequency domain method of moments solution, NEC-2, developed at Lawrence Livermore National Laboratory. The second code was a time domain finite difference solution of Maxwell's equations to solve for the scattered fields. Once the codes were implemented on the hypercube and verified to obtain correct solutions by comparing the results with those from sequential runs, several measures were used to evaluate the performance of the two codes. First, a comparison was provided of the problem size possible on the hypercube with 128 megabytes of memory for a 32-node configuration with that available in a typical sequential user environment of 4 to 8 megabytes. Then, the performance of the codes was anlyzed for the computational speedup attained by the parallel architecture
A Primer on Laplacian Dynamics in Directed Graphs
We analyze the asymptotic behavior of general first order Laplacian processes
on digraphs. The most important ones of these are diffusion and consensus with
both continuous and discrete time. We treat diffusion and consensus as dual
processes. This is the first complete exposition of this material in a single
work.Comment: 24 pages, 5 figures, summer-school/conference on mathematical
modeling of complex systems in Pescara, 201
Wong-Zakai approximation of solutions to reflecting stochastic differential equations on domains in Euclidean spaces II
The strong convergence of Wong-Zakai approximations of the solution to the
reflecting stochastic differential equations was studied in [2]. We continue
the study and prove the strong convergence under weaker assumptions on the
domain.Comment: To appear in "Stochastic Analysis and Applications 2014-In Honour of
Terry Lyons", Springer Proceedings in Mathematics and Statistic
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