Architecture Scenarios Research Articles

PARALLEL COMPUTATION OF TURBULENT COMBUSTION AND FLAME SPREAD IN FIRES

A parallel procedure based on a single-program, multiple-data (SPMD) algorithm is presented for parallel computing of turbulent combustion and flame spread in fires. The computation is based on modeling of radiative turbulent reacting flow and pyrolysis of solid fuel. With angular domain decomposition applied to the parallel computing of radiation and spatial domain decomposition to the computation of nonradiative turbulent reacting flow and solid fuel pyrolysis, the whole computation is distributed among a group of concurrent tasks, which communicate with each other through a message-passing interface library. Using this procedure, a self-developed computational combustion code has been parallelized on both a multiprocessor PC and a symmetric multiprocessor (SMP) system, SGI Origin 2000. The parallelization was verified by comparing the parallel results with sequential results. The performance of the parallel procedure was evaluated using various test cases. As expected, the efficiency of parallelism varies with both computer architecture and case scenario. In general, good efficiency was obtained.

A generic model for Immersive Documentation Environments

We propose a generic model for designing systems relying on augmented reality techniques in the context of an Immersive Documentation Environment (IDE). This model encompasses a user/system interaction paradigm, system architecture and exploitation scenario. We illustrate the use of this model on several virtually documented environment systems providing the user with enhanced interaction capabilities. These systems are dedicated to several applications where the operator needs natural (hands free) access to information, to carry out measurements and/or operate on devices (e.g. maintenance, instruction). These systems merge live images acquired by a video camera with synthetic data (multimedia documents including CAD models and text) and present the result properly registered in the real world. Vocal commands as well as multimodal interaction, associating speech and gesture, are used to improve interaction.

Quantifying the multi-level nature of tiling interactions

Optimizations, including tiling, often target a single level of memory or parallelism, such as cache. These optimizations usually operate on a level-by-level basis, guided by a cost function parameterized by features of that single level. The benefit of optimizations guided by these one-level cost functions decreases as architectures tend towards a hierarchy of memory and of parallelism. We have identified three common architectural scenarios where a single tiling choice could be improved by using information from multiple levels in concert. For each scenario, we derive multi-level cost functions which guide the optimal choice of tile size and shape, and quantify the improvement gained. We give both analysis and simulation results to support our points.