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71.
J. R. White 《Journal of Materials Science》1985,20(7):2377-2387
The layer removal analysis of residual stress distribution is examined for mouldings which contain depth-varying Young's modulus. The approach is to compute the stress distribution which would be derived from the layer removal procedure if the assumption is made that the Young's modulus is uniform, and to compare it with the actual stress distribution. For this analysis a parabolic stress distribution is assumed to be present, and computed distributions are obtained for two cases, (i) in which the modulus varies linearly from the surface to the centre of the moulding and (ii) in which the modulus has a constant value near to the surface (skin) then changes suddenly to another constant value in the interior (core). The general features of the computed profiles are compared with experimental layer removal analyses conducted on injection-moulded specimens and the extent to which non-uniform modulus influences the results of such studies is discussed. 相似文献
72.
R. S. Lopez R. N. Yong P. Boonsinsuk E. C. Card P. White 《Bulletin of Engineering Geology and the Environment》1987,36(1):43-50
Atomic Energy of Canada Limited and Ontario Hydro are conducting a research program to assess the environmental impact and safety of the concept of disposal of nuclear fuel waste in an underground vault in plutonic rock of the Canadian Shield. The Vault Sealing Program, one of the components of the Nuclear Fuel Waste Management Program, is concerned with the development of materials specifications and emplacement procedures for backfilling the vault. Backfilling materials would surround the nuclear waste containers and fill all vault openings to minimize leaching and movement of radionuclides. This paper presents the procedure followed to select candidate backfill materials, the integration of mathematical modelling studies and physical testing for the definition of materials specifications, and the principal elements of the recommended handling and emplacement systems. 相似文献
73.
D. J. White 《OR Spectrum》1987,9(1):13-22
Summary This paper deals with discounted Markov decision processes, Markov with respect to a finite statespaceI, where for eachiI, and each decision epocht, there is a finite action space K(i, t). The paper is concerned with problems which are formulated in terms of the discounted rewards in several ways. In order to ensure that optimal, or near optimal, policies are obtained, the state spaceI is extended to augmented state-spaces A(n), or A(), including the accumulated discounted rewards. Specimen problems are formulated and some computational aspects examined.
Zusammenfassung Es werden diskontierte Markovsche Entscheidungsprozesse behandelt mit endlichem Zustandsraum I, wobei die Mengen der zulässigen Entscheidungen K(i, t) vom Zustandi I und vom Zeitpunktt abhängen können. Es werden verschiedene Zielfunktionen betrachtet, die jeweils als Funktion des diskontierten Gesamtgewinns (nicht dessen Erwartungswerts) formuliert werden. Um optimale oder fast-optimale Politiken zu erhalten ohne die gesamte Vorgeschichte zu registrieren, wird der Zustandsraum um die akkumulierten diskontierten Auszahlungen erweitert. Eine Auswahl solcher Probleme wird exemplarisch diskutiert einschließlich einiger Aspekte der numerischen Behandlung.相似文献
74.
Summary We integrate two numerical procedures for solving the average reward Markov decision process (MDP), standard successive approximations and modified policy iteration with reward revision. Reward revision is the process of revising the reward structure of a second, more computationally desirable MDP so as to produce, in the limit, an optimality equation having a fixed point identical to that associated with the original MDP. A numerical study indicates that for MDP's having a non-sparse transition structure with a small number of relatively large entries per row, the addition of reward revision can have significant computational benefits.
Research supported by NSF Grant ECS-8319355 相似文献
Zusammenfassung Zur Lösung Markovscher Entscheidungsprozesse (MDP) mit Durchschnitts-Kriterium werden zwei numerische Verfahren, nämlich sukzessive Approximation und modifizierte Politik-Iteration, mit einer Transformation, der sogenannten 'Reward-Revision, kombiniert. Bei dieser Transformation werden die Übergangswahrscheinlichkeiten so abgeändert (ausgedünnt), daß das neue Modell sich numerisch günstiger verhält. Dazu müssen die einstufigen Erträge so revidiert werden, daß die Optimalitäts-Gleichung des neuen Modells im Limes mit der des ursprünglichen übereinstimmt. Numerische Untersuchungen zeigen, daß für MDP mit stark besetzten Übergangsmatrizen, bei denen nur an wenigen Stellen je Zeile große Werte stehen, die Anwendung von 'Reward Revision zu wesentlichen Einsparungen an Rechenaufwand führen kann.
Research supported by NSF Grant ECS-8319355 相似文献
75.
A sensor classification scheme 总被引:2,自引:0,他引:2
76.
Jose Gerde Connie Hardy Walter Fehr Pamela J. White 《Journal of the American Oil Chemists' Society》2007,84(6):557-563
Two extruded-expelled physically refined soybean oils with reduced contents of linolenic acid, ultra-low- linolenic acid (ULL,
1.5%) and low-linolenic acid (LL, 2.6%), and a extruded-expelled physically refined control oil (control, 5.3% linolenic acid)
were evaluated by frying French fries in a commercial-like setting for 6 h day−1 during 23 days. The oils became darker, increased in yellow color at the beginning, and became redder and less green throughout
the process. Free fatty acids levels were not different among the oils until day 14, after which, ULL was different from the
control for the remainder of frying. The conjugated dienoic acid values were greatest in the control. Generally, ULL and LL
oils had lower percentages of polar compounds than did the control, providing a frying life 2 days longer than the control
and ~30% increase in frying time. A trained sensory panel evaluated the French fries on days 2, 5, and 6. Buttery and potato
flavors decreased, and rancid and painty flavors increased over frying time for all products. Rancid flavor was highest in
the fries from the control oil. Overall, the ULL and LL oils performed better than did the control oil and ULL tended to perform
better than the LL. 相似文献
77.
Kyung-Ju Choi Joseph E. Spruiell James L. White 《Polymer Engineering and Science》1989,29(21):1524-1527
The present paper describes an analysis of the orientation developed in biaxially stretched polystyrene films in terms of the kinematics of the process and a viscoelastic constitutive equation. It was possible to achieve reasonable agreement of predicted and experimental birefringences through use of a convected Maxwell model and the Rheo-Optical Law. 相似文献
78.
79.
A variety of different imaging techniques produce data which naturally lie in stratified spaces. These spaces consist of smooth regions of maximal dimension glued together along lower dimensional boundaries. Diffusion processes are important as they can be used to represent noise in statistical models on spaces for which standard parametric probability distributions do not exist. We consider particles undergoing Brownian motion in some low dimensional stratified spaces, and obtain analytic solutions to the heat equation specifying the distribution of particles. These solutions play the role of prototypical distributions for studying behaviour near singularities. While probabilistic reasoning can be used to solve the heat equation in some straightforward cases, more generally we construct solutions from eigenfunctions of the Laplacian. Specifically, we solve the heat equation on: open books; two-dimensional cones; the Petersen graph with unit edge length; and the cone of this graph which corresponds to a space of evolutionary trees. 相似文献
80.
Adsorption and desorption of hydrogen and coadsorption of H2 with H2O and CO over Ru(00l) surface have been studied under UHV conditions using the technique of TDS. Surface hydrogen interacts
with adsorbed water resulting in an additional desorption state at 510 K which is not easily displaced by CO, but the total
number of adsorption sites for hydrogen adsorption is independent of the amount of H2O predosed at room temperature. Hydrogen adsorption is blocked easily by CO dose (more than 0.5 L) or a small amount of O(a)
formed from dissociative adsorption of water, and adsorbed hydrogen formed in the absence of significant water is easily displaced
by CO dose at even room temperature. 相似文献