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101.
102.
The problem of determining the maximum mean response level crossing rate of a linear system driven by a partially specified Gaussian load process has been considered. The partial specification of the load is given only in terms of its total average energy. The critical input power spectral (PSD) function, which maximizes the mean response level crossing rate, is obtained. The critical input PSD turns out to be highly narrow-banded which fails to capture the erratic nature of the excitation. Consequently, the trade-off curve between the maximum mean response level crossing rate and the maximum disorder in the input process, quantified in terms of its entropy rate, has been generated. The method of Pareto optimization is used to tackle the conflicting objectives of the simultaneous maximization of the mean response level crossing rate and the input entropy rate. The non-linear multi-objective optimization has been carried out using a recently developed multi-criteria genetic algorithm scheme. Illustrative example of determining the critical input of an axially vibrating rod, excited by a partially specified stationary Gaussian load process, has been considered. 相似文献
103.
中国先进研究堆导流箱流场的数值模拟 总被引:1,自引:1,他引:0
采用目前国内普遍使用的计算流体力学 (CFD)软件PHOENICS 3 2对中国先进研究堆不同结构的导流箱的三维流场进行数值模拟计算。结果表明 :导流箱入口导流板和导流筒能显著改善导流箱入口冷却剂的流动状况 ,获得入口冷却剂沿周向均匀分流的效果 ,达到显著减缓入口冷却剂对垂直辐照孔道导管及安全棒导管直接的横向水力冲刷的设计目的 相似文献
104.
105.
Torsten Bohlin Stefan F. Graebe 《International Journal of Adaptive Control and Signal Processing》1995,9(6):465-490
Grey box identification refers to the practice of identifying dynamical systems in model structures exploiting partial prior information. This contribution reviews a method for stochastic grey box identification and surveys experiences and lessons of applying it to a number of industrial processes. Issues to be addressed include advantages and costs of introducing stochastics into the model, the question of what contribution must be expected from the model designer as opposed to what can be formalized in computer algorithms, and an outlook on future plans to resolve present shortcomings. 相似文献
106.
107.
王志军 《土木建筑与环境工程》1998,20(4):14-20
在深入研究各类迭代控制法的基础上,针对混凝土结构的非线性全过程分析,在常规的位移和弧长控制法中引入了简单适用的考虑路径搜寻和单因加速的方法,明显改善了收敛情况。 相似文献
108.
Directional solidification studies of gelatinized corn starch-water mixtures were undertaken in order to examine, in situ, the freezing behavior of this food model. The solidification rate was controlled by varying sample cell velocity as it moved from a 25°C hot stage to a -25°C cold stage. While freezing at cell velocities ≤7.5 μm/sec, starch granules were alternately pushed or entrapped by the advancing solid-liquid interface producing a segregated structure consisting of alternating high-starch and low-starch bands. At a cell velocity of 10 μm/sec, the frozen product was homogeneous. The relationship between the solid-liquid interface velocity and segregation behavior was quantified and compared to an existing model of particle-interface interactions. 相似文献
109.
前陆盆地前缘隆起是一重要油气聚集带,其特殊的构造部位及复杂的动力学演化过程决定了在该部位有多种圈闭形成和分布。塔里木盆地库车前陆盆地由三叠系、侏罗系烃源岩发育而成的成油体系中的前缘隆起——沙雅隆起区经历了海西期挤压形成雏形、印支—燕山早期挤压定型、燕山晚期—喜马拉雅中期拱张、喜马拉雅晚期挤压拗陷等构造活动阶段,圈闭形成与构造活动相关,成藏与烃源岩演化、幕式构造运动有关,因此各圈闭带的含油气性与圈闭形成期和油气运聚期的匹配有很大关系,由此划分出沙雅前缘隆起区的3级有利构造带。 相似文献
110.
Repetitive processes are a distinct class of 2D systems (i.e. information propagation in two independent directions) of both systems theoretic and applications interest. They cannot be controlled by direct extension of existing techniques from either standard (termed 1D here) or 2D systems theory. In this paper, we exploit their unique physical structure to show how two term, i.e. proportional plus integral (or PI) action, can be used to control these processes to produce desired behavior (as opposed to just stability). 相似文献