4,043,575 research outputs found
A Fast Parallel Cholesky Decomposition Algorithm for Tridiagonal Symmetric Matrices
No full textIn this paper we present a new parallel algorithm for computing the Cholesky decomposition (LL^T) of real symmetric positive-definite tridiagonal matrices. The algorithm consists of a preprocessing and a factoring stage. In the preprocessing stage it determines a rank-(p-1) correction to the original matrix (p=number of processors) by precomputing selected components x_k of the L factor, k=1... p-1. In the factoring stage it performs independent factorizations of p matrices of order n/p. The algorithm is especially suited for machines with both vector and processor parallelism, as confirmed by the experiments carried out on a Connection Machine CM5 with 32 nodes. Let \hat{x}_k and \hat{x}'_k denote the components computed in the preprocessing stage and the corresponding values (re)computed in the factorization stage, respectively. Assuming that \abs{\hat{x}_k/\hat{x}'_k} is small, k=1... p-1, we are able to prove that the algorithm is stable in the backward sense. The above assumption is justified both experimentally and theoretically. In fact, we have found experimentally that \abs{\hat{x}_k/\hat{x}'_k} is small even for ill-conditioned matrices, and we have proven by an a priori analysis that the above ratios are small provided that preprocessing is performed with suitably larger precision
Les Ducs de Bar ou seigneurs et dames de Cassel de la maison ducale de Bar /
No full textOverdruk uit : Mémoires de la société des Lettres, Sciences et Arts de Bar-le-Duc. 2ème Série ; 3(1884
Coriolis effects and the thermal bar
No full textA model for the thermal bar system in the rotating frame that includes unsteady inertia is formulated. Asymptotic solutions are found to the initial value problem in the frictionless, small bottom slope limit. These solutions include inertial oscillations that are significant enough to reverse the circulation ahead of the thermal bar. These asymptotic solutions are compared with numerical solutions of the full model that includes friction. The consequences of both sets of results on the thermal bar in lakes is discussed
Observations from behind the bar: changing patrons' behaviours in response to smoke-free legislation in Scotland.
No full textBACKGROUND: "Smoke-Free" legislation prohibiting smoking in all enclosed public places was introduced in March 2006. This qualitative study presents insights from bar workers about their observations of the changing social bar environment, changing patrons' behaviours and challenges bar workers have faced in managing smoke-free legislation. METHODS: Twelve in-depth interviews were conducted between November 2006 and January 2007 with a purposively-selected sample of bar workers, identified from a larger quantitative study evaluating the impact of the legislation in Scotland [the Bar Workers' Health and Environmental Tobacco Smoke Exposure project (BHETSE)]. RESULTS: Bar workers all spoke of the improvements the legislation had brought to their working lives and the greater comfort it appeared to offer patrons. Bar workers reported that patrons were generally quick to accept and comply with the new law, and that families had become a greater feature of pub life since the legislation. However, they expressed concerns that older men seemed to have had most difficulty adjusting to the legislation and lack of knowledge about the best practices they should adopt in order to reduce the risks of unattended drinks being spiked and of anti-social behaviour associated with patrons moving outside to smoke. CONCLUSION: Smoke-free legislation is changing the social context of smoking in Scotland. Further research to assess the impact the legislation is having on older male smokers and on the incidence of drink spiking would be useful. More specifically, bar workers would benefit from guidance on how to manage issues arising from patrons moving outside to smoke
Synchronization of modified Chua's circuit with x vertical bar x vertical bar function
No full textThis paper considers the chaos synchronization of the modified Chua's circuit with x vertical bar x vertical bar function. We firstly show that a couple of the modified Chua systems with different parameters and initial conditions can be synchronized using active control when the values of parameters both in drive system and response system are known aforehand. Furthermore, based on Lyapunov stability theory we propose an adaptive active control approach to make the states of two identical Chua systems with unknown constant parameters asymptotically synchronized. Moreover the designed controller is independent of those unknown parameters. Numerical simulations are given to validate the proposed synchronization approach
Multicolor chromosome bar codes
No full textChromosome bar codes are multicolor banding patterns produced by fluorescence in situ hybridization (FISH) with differentially labeled and pooled sub-regional DNA probes. These molecular cytogenetic tools facilitate chromosome identification and the delineation of both inter- and intra-chromosomal rearrangements. We present an overview of the various conceptual approaches which can be largely divided into two classes: Simple bar codes designed for chromosome identification and complex bar codes for high resolution aberration screening of entire karyotypes. We address the issue of color redundancy and how to overcome this limitation by complementation of bar codes with whole chromosome painting probes. Copyright (c) 2006 S. Karger AG, Base
An asymptotic model for the hydrodynamics of the thermal bar
No full textAn asymptotic solution is found for the temperature and circulation structure for an unsteady two-dimensional model of the thermal bar phenomenon. The non-rotating case considered here is relevant to laboratory models of the thermal bar. The main implication of the asymptotic results is that the thermal bar might propagate out from the shore more slowly than predicted by a purely heat-balance-based estimate. The solution is discussed in the context of available experimental results
A numerical model of the hydrodynamics of the thermal bar
No full textThe thermal bar phenomenon is modelled numerically by the natural convection of a fluid contained in a two-dimensional triangular domain. The non-rotating case considered here is appropriate to laboratory models of the thermal bar. Three sets of results are presented reflecting varying degrees of nonlinearity. The results are discussed in relation to available theoretical and experimental results
A matrix of measures of court workload
No full textPerformance measures depend on the clarity and consistency of their metrics. The standard unit of analysis of court proceedings is the “case.” Yet the definition of a case varies widely. It may include multiple accused persons and charges, a count of accused persons, the number of informations (a set of charges), or the number of charges. Likewise, whether new cases, completed cases, or the number of cases heard in court are counted make a tremendous difference. In theory, many dozens of caseload measures are possible. Here, a matrix of twelve measures is proposed which balances theoretical exhaustion with practicality. Using data for one year of adult criminal cases in the Provincial Court of British Columbia it is shown that the choice of measure introduces variability of workload over 400 per cent. The matrix is intended as a heuristic device for policy-makers to scrutinise case-based indicators.Peer reviewedFinal article publishe
The -Cauchy problem on weakly -pseudoconvex domains in Stein manifolds
No full textsummary:Let be a Stein manifold of complex dimension and be a relatively compact domain with smooth boundary in . Assume that is a weakly \mbox {-pseudoconvex} domain in . The purpose of this paper is to establish sufficient conditions for the closed range of on . Moreover, we study the \mbox {-problem} on . Specifically, we use the modified weight function method to study the weighted \mbox {-problem} with exact support in . Our method relies on the \mbox {-estimates} by Hörmander (1965) and by Kohn (1973)
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