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Consistent Set (consistent + set)
Selected AbstractsA study into the feasibility of using two parallel sparse direct solvers for the Helmholtz equation on Linux clustersCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2006G. Z. M. Berglund Abstract Two state-of-the-art parallel software packages for the direct solution of sparse linear systems based on LU-decomposition, MUMPS and SuperLU_DIST have been tested as black-box solvers on problems derived from finite difference discretizations of the Helmholtz equation. The target architecture has been Linux clusters, for which no consistent set of tests of the algorithms implemented in these packages has been published. The investigation consists of series of memory and time scalability checks and has focused on examining the applicability of the algorithms when processing very large sparse matrices on Linux cluster platforms. Special emphasis has been put on monitoring the behaviour of the packages when the equation systems need to be solved for multiple right-hand sides, which is the case, for instance, when modelling a seismic survey. The outcome of the tests points at poor efficiency of the tested algorithms during application of the LU-factors in the solution phase on this type of architecture, where the communication acts as an impasse. Copyright © 2005 John Wiley & Sons, Ltd. [source] EVOLUTION OF MOUTHBROODING AND LIFE-HISTORY CORRELATES IN THE FIGHTING FISH GENUS BETTAEVOLUTION, Issue 4 2004Lukas Rüber Abstract The origin of and evolutionary transitions among the extraordinary diverse forms of parental care in teleost fish remain largely unknown. The "safe harbor" hypothesis predicts that the evolution from a "guarding" to a "brooding" form of care in teleost fish is associated with shifts in reproductive and life-history features such as reduced fecundity, and increased egg volume with higher parental investment. Robust phylogenetic hypotheses may help to identify evolutionary changes in key traits associated with differences in the form of parental care. Here, we used reconstruction of ancestral character states to study the evolution of the two forms of parental care, bubble nesting and mouthbrooding in the fighting fish genus Betta. We also applied a comparative analysis using the phylogenetic generalized least-squares method to test the "safe harbor" hypothesis by evaluating differences between the two forms of parental care in standard length, life-history traits, and three habitat variables. Evolutionary hypotheses were derived from the first molecular phylogeny (nuclear and mitochondrial DNA sequence data; 4448 bp) of this speciose group. Ancestral character state reconstructions of the evolution of the form of parental care in the genus Betta, using the methods of unweighted parsimony and maximum likelihood, are uncertain and further indicate a high rate of evolutionary transitions. Applying different weights for the suspected directionality of changes, based on the consistent phenotypic and behavioral differences found between bubble nesters and mouthbrooders, recurrent origin of mouthbrooding in the genus Betta is favored using parsimony. Our comparative analyses further demonstrate that bubble nesters and mouthbrooders do not have a consistent set of life-history correlates. The form of parental care in Betta is correlated only with offspring size, with mouthbrooders having significantly bigger offspring than bubble nesters, but is not correlated with egg volume, clutch size, and broodcare duration, nor with any of the three habitat variables tested. Our results thus challenge the general predictions of the "safe harbor" hypothesis for the evolution of alternative brood care forms in the fighting fish genus Betta. [source] Redox Processes and Water Quality of Selected Principal Aquifer SystemsGROUND WATER, Issue 2 2008P.B. McMahon Reduction/oxidation (redox) conditions in 15 principal aquifer (PA) systems of the United States, and their impact on several water quality issues, were assessed from a large data base collected by the National Water-Quality Assessment Program of the USGS. The logic of these assessments was based on the observed ecological succession of electron acceptors such as dissolved oxygen, nitrate, and sulfate and threshold concentrations of these substrates needed to support active microbial metabolism. Similarly, the utilization of solid-phase electron acceptors such as Mn(IV) and Fe(III) is indicated by the production of dissolved manganese and iron. An internally consistent set of threshold concentration criteria was developed and applied to a large data set of 1692 water samples from the PAs to assess ambient redox conditions. The indicated redox conditions then were related to the occurrence of selected natural (arsenic) and anthropogenic (nitrate and volatile organic compounds) contaminants in ground water. For the natural and anthropogenic contaminants assessed in this study, considering redox conditions as defined by this framework of redox indicator species and threshold concentrations explained many water quality trends observed at a regional scale. An important finding of this study was that samples indicating mixed redox processes provide information on redox heterogeneity that is useful for assessing common water quality issues. Given the interpretive power of the redox framework and given that it is relatively inexpensive and easy to measure the chemical parameters included in the framework, those parameters should be included in routine water quality monitoring programs whenever possible. [source] Compliant grasping with passive forcesJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2005Cai-Hua Xiong Because friction is central to robotic grasp, developing an accurate and tractable model of contact compliance, particularly in the tangential direction, and predicting the passive force closure are crucial to robotic grasping and contact analysis. This paper analyzes the existence of the uncontrollable grasping forces (i.e., passive contact forces) in enveloping grasp or fixturing, and formulates a physical model of compliant enveloping grasp. First, we develop a locally elastic contact model to describe the nonlinear coupling between the contact force with friction and elastic deformation at the individual contact. Further, a set of "compatibility" equations is given so that the elastic deformations among all contacts in the grasping system result in a consistent set of displacements of the object. Then, combining the force equilibrium, the locally elastic contact model, and the "compatibility" conditions, we formulate the natural compliant model of the enveloping grasp system where the passive compliance in joints of fingers is considered, and investigate the stability of the compliant grasp system. The crux of judging passive force closure is to predict the passive contact forces in the grasping system, which is formulated into a nonlinear least square in this paper. Using the globally convergent Levenberg-Marquardt method, we predict contact forces and estimate the passive force closure in the enveloping grasps. Finally, a numerical example is given to verify the proposed compliant enveloping grasp model and the prediction method of passive force closure. © 2005 Wiley Periodicals, Inc. [source] Thermodynamic Reassessment of ZrO2,CaO SystemJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2009Kun Wang In this work, several thermodynamic assessments adopted widely for ZrO2,CaO system are reviewed and examined, the existing discrepancies are summarized, and a new assessment is carried out based on the formation enthalpy of two compounds (CaZr4O9 and Ca6Zr19O44) and experimental activity data concerning cubic solid solution. The thermodynamic parameters of all phases have been optimized by the least squares minimization procedure, a self consistent set of the optimized Gibbs energy parameters has been derived, which can be safely used to extrapolate into the multicomponent system. Compared with experimental data and the results in this work as well as the results reported previously, it is demonstrated that the present thermodynamic assessment is in better agreement with most of the experiments. [source] IS ASIA RESPONSIBLE FOR EXCHANGE RATE MISALIGNMENTS WITHIN THE G20?PACIFIC ECONOMIC REVIEW, Issue 1 2008Agnès Bénassy-Quéré We use a panel data methodology to derive a consistent set of both real effective and bilateral exchange rate misalignments for the G20 currencies. As far as Asia is concerned, two conclusions can be drawn. First, according to our estimations, the five Asian countries in the sample had strongly undervalued currencies at the beginning of 2006. Second, a lack of exchange rate adjustment in Asia has limited impact on other misalignments against the US dollar. Indeed, bilateral misalignments between the USA and any other country mainly depend on real effective misalignments of both countries. [source] Measurement of Household and Family Composition in the United States, 1850,2000POPULATION AND DEVELOPMENT REVIEW, Issue 1 2003Steven Ruggles This article has three goals. First, it explores the effects of changes in census definitions and concepts on the measurement of living arrangements. As part of this analysis, the authors develop new estimates of the number of households and group quarters in each census year since 1850. Second, they evaluate the existing aggregate statistical series on family and household composition, with particular attention to problems in the measurement of subfamilies. Finally, they describe data and methods for developing a consistent set of statistics for the period since 1850 and offer recommendations for the coherent measurement of family and household composition. [source] Implementing a management system architecture frameworkBELL LABS TECHNICAL JOURNAL, Issue 4 2000William C. Goers Any practical vision for the evolution of communications services must include a strategy for how networking vendors make it possible for service providers to manage their networks. While the Telecommunications Management Network (TMN) framework has proponents, the IP services community has shown little interest. Furthermore, operations systems developers have long attempted to produce the best framework, but the technology is outdated before it exists. This paper addresses both issues by presenting an application-driven model for integrated management. This model can be applied to either a "classic" framework orientation or a management application view. What is common between these two views are a management portal, common data models, multiple interface technologies, open and simple network element interfaces, and common operations, administration, and administration (OA&M) tools. These are the elements for which there needs to be a consistent set of interface definitions. They form the basis for the construction of next-generation management applications. [source] Drawing out strengths and building capacity in social work with troubled young womenCHILD & FAMILY SOCIAL WORK, Issue 1 2008Robyn Munford ABSTRACT This paper compares the experiences of a group of marginalized young women with two groups that remained socially engaged. Drawing from a qualitative study of young women aged between 13 and 15 years, we identify four areas (understandings and experiences of well-being, use of space, making wishes, and emotional and household labour) that illuminated the ways in which marginalized young women articulated their experiences differently from those young women who were still engaged in mainstream social life. Drawing on Ungar's work we consider the ways in which marginalized behaviours, which are typically interpreted as socially disruptive and troubled, can also be read as efforts by young women to create a consistent set of social meanings in their lives and to cement reliable relationships around them. Rather than wholly negative, we suggest that these socially disruptive and troubled behaviours should be understood as having health-enhancing qualities, given the wider contextual challenges the young women faced, and as being the best choices they could make given their circumstances. Social work and support that assists young women on the margins needs to actively engage with these health-enhancing qualities and to come to a sensitized understanding of the way in which these young women understand their interpersonal worlds. [source] | ||||||||||||||||