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A novel framework is provided for very fast model-based reinforcement learning in continuous state and action spaces. It requires probabilistic models that explicitly characterize their levels of condence. Within the framework, exible, non-parametric models are used to describe the world based on previously collected experience. It demonstrates learning on the cart-pole problem in a setting where very limited prior knowledge about the task has been provided. Learning progressed rapidly, and a good policy found after only a small number of iterations.

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<正> 尽管激光分离同位素(LIS)才出现十几年,但由于其突出优点,受到世界各国的重视,发展极快。其中有大量课题与力学紧密相关,但迄未见到从这两个乍看起来关系不大的学术领域的结合上作出的总结和评述。本文希望填补这一空白。 1.激光同位素分离 从天然矿物或人工产物中将对人类用处较大的同位素分离出来,对于国民经济和军事应用十分重要。例如,天然矿物中铀235的含量只有约0.7%;而世界

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本文是作者的盘状星系三维密度波工作的第一部分.文中给出了在厚度参数ε及准单色波参数ε_

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<正> 为什么十七世纪以前没有真正的“科学”? 公元前三世纪,希腊文化曾经有过高度的发展。阿基米德(287—212,B.C.)的静力学,欧几里得(300,B.C.)的几何学,都是杰出的科学先驱例子。但是最有影响的亚里士多德(384—322,B.C.)的动力学,却是一些荒谬的唯心臆测。可是由于亚里士多德在学术界的权威性,他的思想整整统治了西方经院学派达两千年之久,其中经过随着希腊文化的衰

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O regimento interno da Câmara dos Deputados está nas páginas 3877-3887 do Diário do Congresso Nacional.

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利用分离式Hopkinson压杆和MTS通用材料试验机研究了SiC_p/6151Al颗粒增强复合材料在不同应变率下的变形行为和增强颗粒的尺寸对复合材料微结构及变形行为的影响。结果表明,对于在不同应变率下的SiC_p/6151Al复合材料,增强颗粒尺寸大小的流动应力高于增强颗粒尺寸的流动应力。根据位错强化理论中的Hall-Petch关系对这个结果进行了解释。首次在实验上观测到增强颗粒对复合材料微损伤-微带形成的影响,并根据微带(microband)形成的双位错墙理论(double dislocation walls), 分析了增强颗粒对复合材料微带损伤及力学性能影响的微结构效应。

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245 p. : il.

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利用脉冲辐照研究超高温度梯度下表层预轩ZrO_2纳米颗粒涂层的18-8奥氏体不锈钢的快凝组织形态、微结构特征及力学性质,结果表明,在表层约15μm范围内形成Zr的合金化微区,Zr最大含量(原子分数)为43.3%,但Zr成分分布存在不连续特征;预置纳米ZrO_2陶瓷涂层明显提高了激光作用深度。超高温梯度和高冷却速度显著细化了快凝亚组织并得到超细枝晶及胞晶,并观察到位错胞及栅栏孪晶两类亚晶,而激光熔区的外延生长机制未使晶粒细化。激光辐照后,合金化区硬度增加而弹性模量降低,其余部分硬度增加而弹性模量无变化。

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The purpose of the project is to develop sustained small-scale cage fish culture in inland and coastal waters through improved understanding of the social, institutional and resource environment of resource poor groups. Two Asian countries, Bangladesh (inland systems) and Vietnam (marine), were studied with this workshop bringing together both sides of the project together with representatives of collaborative institutions, government departments and universities. Addressing the overall aim of producing guidelines for the planning and extension of cage aquaculture in Asia a combination of group work and plenary discussion was conducted producing the following outputs. 1) An assessment of cage aquaculture potential, 2) Development options for small-scale cage culture, 3) A review of tools and methodologies and 4) Policy initiatives for sustainable cage culture development. Key issues raised were the use of outputs as a guide to be adapted to regional circumstances to facilitate farmer and extension worker discussion and not as a rigid methodology. The degree of linkage between development, research and government institutions was also considered a crucial factor in benefiting the research and development of cage culture at the local, regional and national level and vital in affecting the future policies by both development and government institutions. [PDF contains 242 pages]