Dynamic reliability models with conditional proportional hazards

A dynamic approach to the stochastic modelling of reliability systems is further explored. This modelling approach is particularly appropriate for load-sharing, software reliability, and multivariate failure-time models, where component failure characteristics are affected by their degree of use, amount of load, or extent of stresses experienced. This approach incorporates the intuitive notion that when a set of components in a coherent system fail at a certain time, there is a jump from one structure function to another which governs the residual lifetimes of the remaining functioning components, and since the component lifetimes are intrinsically affected by the structure function which they constitute, then at such a failure time there should also be a jump in the stochastic structure of the lifetimes of the remaining components. For such dynamically-modelled systems, the stochastic characteristics of their jump times are studied. These properties of the jump times allow us to obtain the properties of the lifetime of the system. In particular, for a Markov dynamic model, specific expressions for the exact distribution functions of the jump times are obtained for a general coherent system, a parallel system, and a series-parallel system. We derive a new family of distribution functions which describes the distributions of the jump times for a dynamically-modelled system.     

Incomplete block designs for symmetrical parallel line assays

New series of incomplete block designs for symmetrical parallel lines are proposed. From these designs important contrasts like L_p, L₁ and L′₁ are estimated free from block effects. In addition to these, other odd order contrasts are also estimated orthogonal to block effects. The designs are shown to have simple analysis.     

联络及其在现代物理中的解释

本文从曲线坐标、曲面上向量平移入手,导入了联络,继而引入协变微分、短程线及曲率张量,最后指明联络在广义相对论中的意义。     

Graph Algorithms with Small Communication Costs

We study minimizing communication cost in parallel algorithm design, by minimizing the number of communication phases in coarse-grained parallel computers. There have been several recent papers dealing with parallel algorithms of small communication cost under different models. Most of these results are for computational geometry problems. For these problems it has been possible to decompose tasks into appropriate subproblems in a communication-efficient way. It appears to be somewhat more difficult to design parallel algorithms with small communication phases for graph theory problems. In this paper we focus on the design of deterministic algorithms with a small number of communication phases for the list ranking problem and the shortest path problem.     

On Approximating a Scheduling Problem

Given a set of communication tasks (best described in terms of a weighted bipartite graph where one set of nodes denotes the senders, the other set the receivers, edges are communication tasks, and the weight of an edge is the time required for transmission), we wish to minimize the total time required for the completion of all communication tasks assuming that tasks can be preempted (that is, each edge can be subdivided into many edges with weights adding up to the edge's original weight) and that preemption comes with a cost. In this paper, we first prove that one cannot approximate this problem within a factor smaller than unless P=NP. It is known that a simple approximation algorithm achieves within a ratio of two (H. Choi and S.L. Hakimi, Algorithmica, vol. 3, pp. 223–245, 1988). However, our experimental results show that its performance is worse than the originally proposed heuristic algorithm (I.S. Gopal and C.K. Wong, IEEE Transactions on Communications, vol. 33, pp. 497–501, 1985). We devise a more sophisticated algorithm, called the potential function algorithm which, on the one hand, achieves a provable approximation ratio of two, and on the other hand, shows very good experimental performance. Moreover, the way in which our more sophisticated algorithm derives from the simple one, suggests a hierarchy of algorithms, all of which have a worst-case performance at most two, but which we suspect to have increasingly better performance, both in worst case and with actual instances.     

模拟复合正交神经网络在轴向磁轴承中的控制研究

在数字复合正交神经网络(NN)的基础上提出一种模拟复合正交神经网络,并用于轴向磁轴承的控制中.控制器采用模拟复合正交神经网络与PID的并行控制方法,对带有负载干扰的轴向磁轴承控制系统作了PID控制与NN PID控制的仿真实验.仿真结果表明,相对于常规PID控制器,该并行控制法具有非常好的抗干扰与自适应能力,获得了满意的控制效果.     

自然人性的发现和表现——李贽“童心说”与欧洲人文主义比较

少数民族文化与文论经典为中国乃至世界文化与文论做出了独特的贡献。彼特拉克开欧洲近代启蒙思想之端,被誉为人文主义之父,明代回族思想家、文学理论批评家李贽首倡＂童心说＂,喊出中国近代哲学、美学、文学第一声,似也堪称中国启蒙思想之父。人文主义和＂童心说＂在哲学上构建了自然人性论,并以之为武器批判天主教神学和宋明＂新理学＂——＂新神学＂中的禁欲主义、蒙昧主义和专制主义。人文主义和＂童心说＂的文艺思想都是其哲学思想的延伸,以自然人性论为基础和本质内涵,都主张把觉醒后的人作为文学作品的主人公,都主张从市民中找诗,都主张作家要具有人文主义思想或＂童心＂并彰扬人文主义思想或＂童心＂等。欧洲人文主义者打着＂回到古希腊＂的旗号,创造资产阶级新文化新文学;李贽推崇、尊重孔孟开创的先秦儒学,猛烈批判程朱理学,其非孔反孔言论主要针对道学家把孔子思想神化为亘古不变的教条而发。欧洲人文主义者秉承模仿说,更突出社会生活对作家创作的决定作用,更强调文学的反映功能;李贽秉承＂言志＂、＂缘情＂说,更突出创作主体的作用,更强调文学的表现功能,并形成了比较系统的自然人性表现观。李贽的＂童心说＂与欧洲人文主义无＂贸易关系＂,但与人文主义文心相通,并体现着中华文化与文论的传统和特色。     

版权穷竭的空间效力范围与平行进口问题研究

版权穷竭制度是版权法律制度上一项非常重要的制度,这一制度在全世界范围内已经得到了普遍的认可,但是关于版权穷竭的空间效力范围问题,各国学者却始终没有达成一致,目前在学界对于这一问题主要有两种观点,即国内穷竭说与国际穷竭说,并且大部分学者又以国际穷竭或国内穷竭来佐证或反对平行进口。实际上,各国在制定法规时,并非单纯地依据知识产权法原理,而是更多地考虑了本国贸易利益的需要。贸易层面的利益冲突才是造成平行进口问题分歧的根源所在。