FPGA acceleration of the phylogenetic likelihood function for Bayesian MCMC inference methods

Background Likelihood (ML)-based phylogenetic inference has become a popular method for estimating the evolutionary relationships among species based on genomic sequence data. This method is used in applications such as RAxML, GARLI, MrBayes, PAML, and PAUP. The Phylogenetic Likelihood Function (PLF) is an important kernel computation for this method. The PLF consists of a loop with no conditional behavior or dependencies between iterations. As such it contains a high potential for exploiting parallelism using micro-architectural techniques. In this paper, we describe a technique for mapping the PLF and supporting logic onto a Field Programmable Gate Array (FPGA)-based co-processor. By leveraging the FPGA\u27s on-chip DSP modules and the high-bandwidth local memory attached to the FPGA, the resultant co-processor can accelerate ML-based methods and outperform state-of-the-art multi-core processors. Results We use the MrBayes 3 tool as a framework for designing our co-processor. For large datasets, we estimate that our accelerated MrBayes, if run on a current-generation FPGA, achieves a 10× speedup relative to software running on a state-of-the-art server-class microprocessor. The FPGA-based implementation achieves its performance by deeply pipelining the likelihood computations, performing multiple floating-point operations in parallel, and through a natural log approximation that is chosen specifically to leverage a deeply pipelined custom architecture. Conclusions Heterogeneous computing, which combines general-purpose processors with special-purpose co-processors such as FPGAs and GPUs, is a promising approach for high-performance phylogeny inference as shown by the growing body of literature in this field. FPGAs in particular are well-suited for this task because of their low power consumption as compared to many-core processors and Graphics Processor Units (GPUs)

Measurement of secondary emissions during laser cutting of steel equipments

In order to dismantle some equipments of an obsolete reprocessing plant in Marcoule, studies were carried out by IRSN (Institut de Radioprotection et de Sûreté Nucléaire)/DSU/SERAC in cooperation with CEA (power laser group) on the laser cutting of steel structures, on the request of AREVA NC/Marcoule (UP1 dismantling project manager) and CEA/UMODD (UP1 dismantling owner). These studies were aimed at:•quantifying and characterizing the secondary emissions produced by Nd-YAG laser cutting of Uranus 65 steel pieces and examining the influence of different parameters,•qualifying a prefiltration technique and particularly an electrostatic precipitator,•comparing the Nd-YAG laser used with other cutting tools previously studied especially on aerosol production and aerosol size distribution. © 2008 Elsevier B.V. All rights reserved

Ability of X80 steel for hydrogen gas transmission pipelines CATHY-GDF project

By limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explores the ability of an industrial X80 grade for the transmission of pressurised hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Then, tensile, toughness, fatigue and disc tests are performed on the base material and on the welds. Moreover, an apparatus has been designed to simulate the hydrogen gas impact on a damaged pipe section. Hydrogen gas influence has been evaluated by FEM coupling H diffusion and mechanical fields. The results stress the necessity to improve the guidelines, updating the safety margins, for high-strength hydrogen transmission pipelines

Ability of X80 steel for hydrogen gas transmission pipelines CATHY-GDF project

By limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explores the ability of an industrial X80 grade for the transmission of pressurised hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Then, tensile, toughness, fatigue and disc tests are performed on the base material and on the welds. Moreover, an apparatus has been designed to simulate the hydrogen gas impact on a damaged pipe section. Hydrogen gas influence has been evaluated by FEM coupling H diffusion and mechanical fields. The results stress the necessity to improve the guidelines, updating the safety margins, for high-strength hydrogen transmission pipelines

Ability of X80 steel for hydrogen gas transmission pipelines CATHY-GDF project

By limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explores the ability of an industrial X80 grade for the transmission of pressurised hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Then, tensile, toughness, fatigue and disc tests are performed on the base material and on the welds. Moreover, an apparatus has been designed to simulate the hydrogen gas impact on a damaged pipe section. Hydrogen gas influence has been evaluated by FEM coupling H diffusion and mechanical fields. The results stress the necessity to improve the guidelines, updating the safety margins, for high-strength hydrogen transmission pipelines

Ability of X80 steel for hydrogen gas transmission pipelines CATHY-GDF project

By limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explores the ability of an industrial X80 grade for the transmission of pressurised hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Then, tensile, toughness, fatigue and disc tests are performed on the base material and on the welds. Moreover, an apparatus has been designed to simulate the hydrogen gas impact on a damaged pipe section. Hydrogen gas influence has been evaluated by FEM coupling H diffusion and mechanical fields. The results stress the necessity to improve the guidelines, updating the safety margins, for high-strength hydrogen transmission pipelines

Recommendations on X80 steel for the design of hydrogen gas transmission pipelines

International audienceBy limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines on long distance. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explored the ability of an industrial X80 grade for the transmission of pressurized hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Indeed, tensile, toughness, crack propagation and disc rupture tests have been performed. From these results, the effect of hydrogen pressure on the size of some critical defects has been analyzed allowing proposing some recommendations on the design of X80 pipe for hydrogen transport. Cost of hydrogen transport could be several times higher than natural gas one for a given energy amount. Moreover, building hydrogen pipeline using high grade steels could induce a 10 to 40% cost benefit instead of using low grade steels, despite their lower hydrogen susceptibility