13,758 research outputs found
Putting a Slug to Work
In this article, the authors explore various uses of inexpensive embedded Linux devices such as the Linksys NSLU2 ( slug ). Embedded computing is a topic of growing interest. Although novel architectures such as cell processors, graphics processors (GPUs), and FPGAs are growing in popularity, conventional microproessor designs such as Intel\u27s Xscale (ARM) and Atom pack a punch in a small footprint, not to mention being widely supported by commodity operating system and development tools. We\u27re convinced that this entire space is a tool worth keeping in the scientific programmer\u27s and software developer\u27s toolchests
Dynamics of a structured slug population model in the absence of seasonal variation
We develop a novel, nonlinear structured population model for the slug Deroceras reticulatum, a highly significant agricultural pest of great economic impact, in both organic and non-organic settings. In the absence of seasonal variations, we numerically explore the effect of life history traits that are dependent on an individual's size and measures of population biomass. We conduct a systematic exploration of parameter space and highlight the main mechanisms and implications of model design. A major conclusion of this work is that strong size dependent predation significantly adjusts the competitive balance, leading to non-monotonic steady state solutions and slowly decaying transients consisting of distinct generational cycles. Furthermore, we demonstrate how a simple ratio of adult to juvenile biomass can act as a useful diagnostic to distinguish between predated and non-predated environments, and may be useful in agricultural settings
Inverse Uncertainty Quantification using the Modular Bayesian Approach based on Gaussian Process, Part 2: Application to TRACE
Inverse Uncertainty Quantification (UQ) is a process to quantify the
uncertainties in random input parameters while achieving consistency between
code simulations and physical observations. In this paper, we performed inverse
UQ using an improved modular Bayesian approach based on Gaussian Process (GP)
for TRACE physical model parameters using the BWR Full-size Fine-Mesh Bundle
Tests (BFBT) benchmark steady-state void fraction data. The model discrepancy
is described with a GP emulator. Numerical tests have demonstrated that such
treatment of model discrepancy can avoid over-fitting. Furthermore, we
constructed a fast-running and accurate GP emulator to replace TRACE full model
during Markov Chain Monte Carlo (MCMC) sampling. The computational cost was
demonstrated to be reduced by several orders of magnitude.
A sequential approach was also developed for efficient test source allocation
(TSA) for inverse UQ and validation. This sequential TSA methodology first
selects experimental tests for validation that has a full coverage of the test
domain to avoid extrapolation of model discrepancy term when evaluated at input
setting of tests for inverse UQ. Then it selects tests that tend to reside in
the unfilled zones of the test domain for inverse UQ, so that one can extract
the most information for posterior probability distributions of calibration
parameters using only a relatively small number of tests. This research
addresses the "lack of input uncertainty information" issue for TRACE physical
input parameters, which was usually ignored or described using expert opinion
or user self-assessment in previous work. The resulting posterior probability
distributions of TRACE parameters can be used in future uncertainty,
sensitivity and validation studies of TRACE code for nuclear reactor system
design and safety analysis
Content and action: The guidance theory of representation
The current essay introduces the guidance theory of representation, according to which the content and intentionality of representations can be accounted for in terms of the way they provide guidance for action. We offer a brief account of the biological origins of representation, a formal characterization of the guidance theory, some examples of its use, and show how the guidance theory handles some traditional problem cases for representation: the problems of error and of representation of fictional and abstract entities
Spartan Daily, April 23, 2008
Volume 130, Issue 46https://scholarworks.sjsu.edu/spartandaily/10472/thumbnail.jp
Ground resonance analysis using a substructure modeling approach
A convenient and versatile procedure for modeling and analyzing ground resonance phenomena is described and illustrated. A computer program is used which dynamically couples differential equations with nonlinear and time dependent coefficients. Each set of differential equations may represent a component such as a rotor, fuselage, landing gear, or a failed damper. Arbitrary combinations of such components may be formulated into a model of a system. When the coupled equations are formed, a procedure is executed which uses a Floquet analysis to determine the stability of the system. Illustrations of the use of the procedures along with the numerical examples are presented
Development of meteoroid simulators for hypervelocity impact studies
Developing aluminum meteoritic simulators for hypervelocity impact test using shaped charge
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