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141.
Robert M. Wirtshafter 《Energy Policy》1985,13(2):143-155
Utility conservation programmes are designed to benefit both participants and non-participants. This article outlines the issues involved in designing conservation programmes for utilities and determining the appropriate amount of incentives that can be provided to participants without harming non-participants. More importantly, the article discusses the issue of access to the programmes by utility customers. It concludes that it is the existing restrictions to participation, and not the level of compensation, that are of greatest concern to non-participants. A number of utility programmes designed to eliminate the problem of non-participation are reviewed. 相似文献
142.
Gastric ulceration of rats stressed by restraint in 19°C water for 75 min was markedly increased by allowing a 75-min postrestraint room-temperature rest period during which the rat was exposed to cues that had previously been associated with the delivery of 80 5-s uncontrollable electric shocks distributed over four sessions. This effect obtained equally without regard to whether "danger cues" were punctate signals or constant contextual cues or whether contextual ones were interrupted by punctate safety signals. The experimental treatments used were unusual in that they equated the groups on their total conditioning history and thus allowed a more pure look at the poststress effect than heretofore. Other groups provided controls for prior shocks, rest, and their interaction as well as handling. Analyses of corticosterone after the stress or stress-rest cycle revealed only a general decline in corticosterone levels with rest undifferentiated across groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
143.
Recent studies in our laboratory have suggested that monogamy may be the preferred mating system in the Djungarian hamster (Phodopus campbelli), whereas the available evidence for the closely related Siberian hamster (P. sungorus) does not show the same pattern. Here we examine the behavior of male–female dyads of both species interacting during 1-hr tests in large, familiar habitats containing defensible nest boxes, food, and water. Levels of aggression within pairs were low, compared with those seen during brief intrasexual encounters, whereas affiliative behaviors, such as sniffs, were high. P. campbelli scent marked more than twice as frequently as P. sungorus. Females of both species scent marked at a constant rate irrespective of their location in the habitat, whereas males scent marked at a higher rate in the female's home area. Two major features of the copulatory pattern differed between the two species: (a) The duration of the ejaculatory lock was five times longer in P. sungorus than in P. campbelli. (b) Both species had approximately the same number of mounts in each ejaculatory series, but the intromission/mount ratio was significantly higher in P. sungorus. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
144.
Clinical drug infusion protocols, such as a single bolus followed by a constant drip, do not establish and maintain therapeutic drug levels in an optimal manner. We have investigated a system in which the patient, drug pump, drug assay, and a pump controller are incorporated into an adaptive configuration. The system, which we have simulated on a computer, uses an adaptive approach in which the pump controller operates with a model of the subject response. The model is fit to the specific subject by a regression analysis of the subject's response, obtained by assay of the subject's blood. 相似文献
145.
In order to obtain a bonded wood product from the tree, wood must be subjected to a series of processes. These include, among others, vital processes like drying of the green wood and machining of the surfaces of the dried wood in preparation for bonding. However, when wood is machined with dull blades, thermal degradation of the wood frequently occurs. The effects of kiln drying and thermal degradation of wood on the performance of the adhesive joints subsequently formed from such wood were investigated. Tapered double cantilever beam (TDCB) test specimens obtained from hard maple and phenol–resorcinol–formaldehyde (PRF) adhesives were used in the investigations. The enhancement of fracture energy due to the reduction in the moisture content of wood, the improved performance of adhesive joints due to rejointing of wood surfaces before bonding, and the reduction of adhesive joint strength resulting from thermal degradation of wood are presented and discussed. 相似文献
146.
147.
David R. Oakley Robert H. Sues Graham S. Rhodes 《Probabilistic Engineering Mechanics》1998,13(1):15-26
This paper presents a methodology to solve a new class of stochastic optimization problems for multidisciplinary systems (multidisciplinary stochastic optimization or MSO) wherein the objective is to maximize system mechanical performance (e.g. aerodynamic efficiency) while satisfying reliability-based constraints (e.g. structural safety). Multidisciplinary problems require a different solution approach than those solved in earlier research in reliability-based structural optimization (single discipline) wherein the goal is usually to minimize weight (or cost) for a structural configuration subject to a limiting probability of failure or to minimize probability of failure subject to a limiting weight (or cost). For the problems solved herein, the objective is to maximize performance over the range of operating conditions, while satisfying constraints that ensure safe and reliable operation. Because the objective is performance based and because the constraints are reliability based, the random variables used in the objective must model variability in operating conditions, while the random variables used in the constraints must model uncertainty in extreme values (to ensure safety). Thus, the problem must be formulated to treat these two different types of variables at the same time, including the case when the same physical quantity (e.g. a particular load) appears in both the objective function and the constraints. In addition, the problem must be formulated to treat multiple load cases, which can again require modeling the same physical quantity with different random variables. Deterministic multidisciplinary optimization (MDO) problems have advanced to the stage where they are now commonly formulated with multiple load cases and multiple disciplines governing the objective and constraints. This advancement has enabled MDO to solve more realistic problems of much more practical interest. The formulation used herein solves stochastic optimization problems that are posed in this same way, enabling similar practical benefits but, in addition, producing optimum designs that are more robust than the deterministic optimum designs (since uncertainties are accounted for during the optimization process). The methodology has been implemented in the form of a baseline MSO shell that executes on both a massively parallel computer and a network of workstations. The MSO shell is demonstrated herein by a stochastic shape optimization of an axial compressor blade involving fully coupled aero-structural analysis. 相似文献
148.
Fast parallel Preconditioned Conjugate Gradient algorithms for robot manipulator dynamics simulation
In this paper fast parallel Preconditioned Conjugate Gradient (PCG) algorithms for robot manipulator forward dynamics, or dynamic simulation, problem are presented. By exploiting the inherent structure of the forward dynamics problem, suitable preconditioners are devised to accelerate the iterations. Also, based on the choice of preconditioners, a modified dynamic formulation is used to speedup both serial and parallel computation of each iteration. The implementation of the parallel algorithms on two interconnected processor arrays is discussed and their computation and communication complexities are analyzed. The simulation results for a Puma Arm are presented to illustrate the effectiveness of the proposed preconditioners. With a faster convergence due to preconditioning and a faster computation of iterations due to parallelization, the developed parallel PCG algorithms represent the fastest alternative for parallel computation of the problem withO(n) processors. 相似文献
149.
This paper is concerned with improvement in optical image quality by image restoration. Image restoration is an ill-posed
inverse problem which involves the removal or minimization of degradations caused by noise and blur in an image, resulting
from, in this case, imaging through a medium. Our work here concerns the use of the underlying Toeplitz structure of such
problems, and associated techniques for accelerating the convergence of iterative image restoration computations. Denoising
methods, including total variation minimization, followed by segmentation-based preconditioning methods for minimum residual
conjugate gradient iterations, are investigated. Regularization is accomplished by segmenting the image into (smooth) segments
and varying the preconditioners across the segments. By taking advantage of the Toeplitz structure, our algorithms can be
implemented with computational complexity of onlyO (ln
2 logn), wheren
2 is the number of pixels in the image andl is the number of segments used. Also, parallelization is straightforward. Numerical tests are reported for atmospheric imaging
problems, including the case of spatially varying blur.
Research supported in part by a National Science Foundation Postdoctoral Research Fellowship.
Research sponsored by the U.S. Air Force Office of Scientific Research under grant F49620-97-1-1039.
Research sponsored by the U.S. Air Force Office of Scientific Research under grant F49620-97-1-0139, and by the National Science
Foundation under grant CCR-96-23356.
Research sponsored by the National Science Foundation under grant CCR-96-23356. 相似文献
150.
Client/server, open systems, joint application development, and legacy systems—what happens when the silver bullet meets the glass house? And what does all of this have to do with end-user computing, anyway? Read this column and find out. 相似文献