Using coordination to parallelize sparse-grid methods for 3D CFD problems

The good parallel computing properties of sparse-grid solution techniques are investigated. For this, an existing sequential CFD code for a standard 3D problem from computational aerodynamics is restructured into a parallel application. The restructuring is organized according to a master/slave protocol. The coordinator modules developed thereby are implemented in the coordination language Manifold and are generally applicable. Performance results are given for both the sequential and parallel version of the code. The results are promising, the paper contributes to the state-of-the-art in improving the efficiency of large-scale computations. Also a theoretical analysis is made of speed-up through parallelization in a multi-user single-machine environment

Coordination of a parallel proposition solver

In this paper we describe an experiment in which {sc Manifold is used to coordinate the interprocess communication in a parallelized proposition solver. {sc Manifold is very well suited for applications involving dynamic process creation and dynamically changing (ir)regular communication patterns among sets of independent concurrent cooperating processes. The idea in this case study is simple. The proposition solver consists of a fixed numbers of separate processing units which communicate with each other such that the output of one serves as the input for the other. Because one of the processing units performs a computation intensive job, we introduce a master/worker protocol to divide its computations. We show that this protocol implemented in {sc Manifold adds another hierarchic layer to the application but leaves the previous layers intact. This modularity of {sc Manifold offers the possibility to introduce concurrency step by step. We also verify the implementation of the proposition solver using a simple family of assertions and give some performance results

Parallel, distributed-memory implementation of sparse-grid methods for three-dimensional fluid-flow computations

A workable approach for modernization of existing software into parallel/distributed applications is through coarse-grain restructuring. If, for instance, entire subroutines of legacy code can be plugged into a new structure, the investment required for the re-discovery o

Parallel, distributed-memory implementation of a sparse-grid method for time-dependent advection-diffusion problems

A workable approach for modernizing existing software into parallel/distributed applications is through coarse-grain restructuring. If, for instance, entire subroutines of legacy code can be plugged into a new structure, the investment required for the re-discovery of the d

Probing problems and priorities in oral health (care) among community dwelling elderly in the Netherlands: a mixed method study

Background: Complex dentitions and decline in adequate oral hygiene in elderly may lead to poor oral health. This may have impact on their general health, wellbeing and quality of life. With increased longevity, the problems and needs in oral health of community dwelling elderly lead to changes in oral health care needs. We identified and prioritized problems and needs in oral health of community dwelling elderly. Methods: The problems and needs in oral health of community dwelling elderly were elicited during focus groups and interviews. The list of problems and needs derived thereof was presented to 97 elderly who prioritized these. Results: Overall, older people appeared to be satisfied with their current oral health, and the maintenance and care for their oral health. Cost of care was identified as a major problem in general. There are differences in current perceived problems and needs and problems and needs anticipated for the future. Perceived current problems and needs concern dental care provision and knowledge on oral health of professionals and patients. For anticipated future problems and needs the importance of daily oral care by caregivers was prioritised, while emphasis was placed on fear of losing autonomy. Conclusion: It is important to take the perspectives and expectations of elderly into account in policy and planning of future oral health care practice, because these differ from the perspectives of dental professionals