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Few Milliseconds (few + millisecond)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Fast and Scalable CPU/GPU Collision Detection for Rigid and Deformable Surfaces

COMPUTER GRAPHICS FORUM, Issue 5 2010
Simon Pabst
Abstract We present a new hybrid CPU/GPU collision detection technique for rigid and deformable objects based on spatial subdivision. Our approach efficiently exploits the massive computational capabilities of modern CPUs and GPUs commonly found in off-the-shelf computer systems. The algorithm is specifically tailored to be highly scalable on both the CPU and the GPU sides. We can compute discrete and continuous external and self-collisions of non-penetrating rigid and deformable objects consisting of many tens of thousands of triangles in a few milliseconds on a modern PC. Our approach is orders of magnitude faster than earlier CPU-based approaches and up to twice as fast as the most recent GPU-based techniques. [source]

Numerical simulation of thermal runaway phenomena in silicon semiconductor devices

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2002
Kazanori Shioda
Abstract A mathematical model for heat production due to thermal excitation of conductive electrons and positive holes in a semiconductor pn junction is derived and discussed. The model is applied to simulate the thermal runaway phenomena in power electronics semiconductor devices. Our discussion focuses especially on the modeling of unexpected huge currents due to an excessive temperature increase. Calculated dynamics of temperature distributions of a silicon wafer while cooling performance decreases proved it is possible for a silicon wafer to be heated over its melting point in a few milliseconds. Our results indicate that if a local hot spot arises in a wafer, the thermal intrinsic excitation carries an increased diffusion current of minor carriers and a recombination current in the depletion layer of a pn junction. Also it appears to be important that cooling performance should be uniform on the wafer to avoid the growth of hot spots and thermal-runaway itself. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(6): 438,455, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10044 [source]

Electron,cyclotron maser observable modes

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2000
A. Stupp
We investigate wave amplification through the electron,cyclotron maser mechanism. We calculate absorption and emission coefficients without any approximations, also taking into account absorption by the ambient thermal plasma. A power-law energy distribution for the fast electrons is used, as indicated by X-ray and microwave observations. We develop a model for the saturation length and amplification ratio of the maser, scan a large parameter space and calculate the absorption and emission coefficients for every frequency and angle. Previous studies concluded that the unobservable Z mode dominates in the ,p,,B region, and that millisecond spikes are produced in the region ,p,B<0.25. We find that the observable O and X modes can produce emission in the 0.8<,p,B<2 region, which is expected at the footpoints of a flaring magnetic loop. The important criterion for observability is the saturation length and not the growth rate, as was assumed previously, and, even when the Z mode is the most strongly amplified, less strongly amplified O or X modes are still intense enough to be observed. The brightness temperature computed with our model for the saturation length is found to be of order 1016 K and higher. The emission is usually at a frequency of 2.06,B, and at angles of 30°,60° to the magnetic field. The rise time of the amplified emission to maximum is a few tenths of a millisecond to a few milliseconds, and the emission persists for as long as new fast electrons arrive in the maser region. [source]

Numerical valuation of options under Kou's model

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2007
Jari ToivanenArticle first published online: 6 AUG 200
Numerical methods are developed for pricing European and American options under Kou's jump-diffusion model which assumes the price of the underlying asset to behave like a geometrical Brownian motion with a drift and jumps whose size is log-double-exponentially distributed. The price of a European option is given by a partial integro-differential equation (PIDE) while American options lead to a linear complementarity problem (LCP) with the same operator. Spatial differential operators are discretized using finite differences on nonuniform grids and time stepping is performed using the implicit Rannacher scheme. For the evaluation of the integral term easy to implement recursion formulas are derived which have optimal computational cost. When pricing European options the resulting dense linear systems are solved using a stationary iteration. Also for pricing American options similar iterations can be employed. A numerical experiment demonstrates that the described method is very efficient as accurate option prices can be computed in a few milliseconds on a PC. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]