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991.
在水利工程管理当中,从前期决策、勘察设计、建造到运营维护的全过程,引入全过程协同管理,可以产生和助力发挥协同效应.以都江堰工程为例,运用物理-事理-人理方法论(Wuli-Shili-Renli System Approach,以下简称WSR方法论),从物理、事理、人理角度,对协同管理进行系统分析,通过构建基于WSR系统的协同管理三维分析模型、协同管理分析矩阵和协同管理分析框架,为水利工程的协同管理提供启示和借鉴,助力于发挥水利工程协同管理全过程的协同效应. 相似文献
992.
Hoang Tuy Saied Ghannadan Athanasios Migdalas Peter Värbrand 《Mathematical Programming》1996,72(3):229-258
We show that the production-transportation problem involving an arbitrary fixed number of factories with concave production
cost is solvable in strongly polynomial time. The algorithm is based on a parametric approach which takes full advantage of
the specific structure of the problem: monotonicity of the objective function along certain directions, small proportion of
nonlinear variables and combinatorial properties implied by transportation constraints. 相似文献
993.
高阶偏微分方程与概率方法 总被引:3,自引:0,他引:3
二阶偏微分方程与扩散过程的是概率界众所财知的。前者为后者提供了分析依据,后者为前者的解给出了概率表示;如何把这种联系推广到高阶偏微分方程的情形,是很多概率学家近十几年来一直关心的问题。 相似文献
994.
995.
This study examines theoretically the development of early transients for axisymmetric flow of a thin film over a stationary cylindrical substrate of arbitrary shape. The fluid is assumed to emerge from an annular tube as it is driven by a pressure gradient maintained inside the annulus, and/or by gravity in the axial direction. The interplay between inertia, annulus aspect ratio, substrate topography and gravity is particularly emphasized. Initial conditions are found to have a drastic effect on the ensuing flow. The flow is governed by the thin‐film equations of the ‘boundary‐layer’ type, which are solved by expanding the flow field in terms of orthonormal modes in the radial direction. The formulation is validated upon comparison with the similarity solution of Watson (J. Fluid Mech 1964; 20 :481) leading to an excellent agreement when only 2–3 modes are included. The wave and flow structure are examined for high and low inertia. It is found that low‐inertia fluids tend to accumulate near the annulus exit, exhibiting a standing wave that grows with time. This behaviour clearly illustrates the difficulty faced with coating high‐viscosity fluids. The annulus aspect is found to be influential only when inertia is significant; there is less flow resistance for a film over a cylinder of smaller diameter. For high inertia, the free surface evolves similarly to two‐dimensional flow. The substrate topography is found to have a significant effect on transient behaviour, but this effect depends strongly on inertia. It is observed that the flow of a high‐inertia fluid over a step‐down exhibits the formation of a secondary wave that moves upstream of the primary wave. Gravity is found to help the film (coating) flow by halting or prohibiting the wave growth. The initial film profile and velocity distribution dictate whether the fluid will flow downstream or accumulate near the annulus exit. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
996.
本文运用协变方法和么正方法,分别给出了W-N理论和H-N理论量子宇宙波函数的单圈修正;并且讨论两种算法的差异性及矢量-张量引力理论的可行性. 相似文献
997.
从测试的挑剔性、层次性、完全测试的不可能性等特点出发,阐述在新型开发体系原型法下,对田径电算统分系统UniversitySportGame所采用的测试技术,提出了在测试工作中应遵循的几点基本原则 相似文献
998.
999.
U Ayr 《Applied Acoustics》2003,64(2):129-145
The results of a wide acoustic environment survey are presented. Sound pressure measurements were carried out in a group of offices. These measurements lasted for five minutes and the resulting noise spectra were used to calculate the most significant acoustic parameters. During each measurement a questionnaire was administered to workers near each measuring position. The questionnaire asked them to indicate their subjective judgement about noise annoyance, noise loudness and dissatisfaction induced by noise present in the environment. The aim of the research was to investigate the performance of the measured noise indices in describing subjective responses to noise. A new method to calculate the average subjective responses is proposed. The performance of the noise indices was studied by means of linear regression analysis. Finally the A-weighted equivalent sound pressure level proved to be the best index among those analysed in describing subjective auditory sensations. 相似文献
1000.
本文选取1999-2004年间中国城市公共交通行业的面板数据,在Cobb-Douglas函数的基础上运用随机边界法对我国城市公共交通行业的技术效率进行了考察,并从时间、地域、交通工具类型和客运规模方面,分析了该行业的效率差异及其产生原因,旨在为该行业的未来发展和管制改革提供决策依据。研究结果表明,我国城市公共交通行业技术效率情况为:近几年虽有小幅上升,但基数总体不高;东部地区技术效率偏高;客运量大和拥有轨道交通的省市的技术效率较高。 相似文献