并联机构智能优化设计方法研究

本文分析介绍了近年来兴起的智能优化算法——遗传算法用于并联机构优化设计的基本思想和应用方法，以雅可比矩阵的条件数为优化设计目标，建立了Stewart并联机构结构参数优化设计的数学模型，分别采用两种编码方式优化设计了平台的结构参数，并用MATLAB软件编程，得到了较为合理的结果。     

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。     

A NEW APPROACH TO DISCRIMINATION AND CLASSIFICATION USING A HAUSDORFF TYPE DISTANCE

A new method of discrimination and classification based on a Hausdorff type distance is proposed. In two groups, the Hausdorff distance is defined as the sum of the furthest distance of the nearest elements of one set to another. This distance has some useful properties and is exploited in developing a discriminant criterion between individual objects belonging to two groups based on a finite number of classification variables. The discrimination criterion is generalized to more than two groups in a couple of ways. Several data sets are analysed and their classification accuracy is compared to that obtained from linear discriminant function and the results are encouraging. The method in simple, lends itself to parallel computation and imposes less stringent conditions on the data.     

Preemptive Machine Covering on Parallel Machines

This paper investigates the preemptive parallel machine scheduling to maximize the minimum machine completion time. We first show the off-line version can be solved in O(mn) time for general m-uniform-machine case. Then we study the on-line version. We show that any randomized on-line algorithm must have a competitive ratio m for m-uniform-machine case and ∑_{i = 1}^m1/i for m-identical-machine case. Lastly, we focus on two-uniform-machine case. We present an on-line deterministic algorithm whose competitive ratio matches the lower bound of the on-line problem for every machine speed ratio s≥ 1. We further consider the case that idle time is allowed to be introduced in the procedure of assigning jobs and the objective becomes to maximize the continuous period of time (starting from time zero) when both machines are busy. We present an on-line deterministic algorithm whose competitive ratio matches the lower bound of the problem for every s≥ 1. We show that randomization does not help.     

柳永的"赋笔为词"与宋初的文学精神

本文在新的层面讨论阐述了柳永词在宋初文学精神的影响下 ,其“赋笔为词”远绍两汉义归雅颂的理性精神 ,并与由汉大赋蜕变而来的宋代文赋呈合流之势 ,从而揭示了柳永“赋笔为词”在词中“宋调”形成的过程中对后世开山意义之一端。     

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.     

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.     

与FFT并行算法相适应的体系结构探讨

介绍了并行ＦＦＴ算法,讨论其在网格和超立方体并行体系结构上的实现方法,并作了多个方面的比较,为高效实现并行ＦＦＴ选择一种合适的体系结构。经研究表明,并行ＦＦＴ算法的最佳体系结构为超立方体。     

Efficient Algorithms for Local Alignment Search

We present efficient algorithms for local alignment search in biological sequences. These algorithms identify maximal segment pairs (MSPs). Our algorithms have the potential of performing better than BLAST (Basic Local Alignment Search Tool) and also are efficiently parallelizable. We employ Fast Fourier Transforms (FFTs). Though several attempts have been made in the past to employ FFTs in sequence analysis, they fail to capture local similarities. Our algorithms employ FFTs in a novel way to identify local similarities. FFT-based techniques have the attractive feature of benefiting from ultrafast special purpose hardware available for digital signal processing.     

袁枚文章理论研究

袁枚文章理论 ,主要有三方面 :( 1 )尚文。经学家与文章家之间 ,袁枚推重文章家 ;文与道之间 ,他特别强调文的重要 ;注重文章的美学价值。 ( 2 )务纯。提倡专务写作 ,以期精诣 ,所为文以纯而不杂为好。 ( 3)尊骈。在消除“骈散对立”的基础之上 ,提倡骈散并尊。其文章理论富有强烈的反传统色彩 ,且体现出很强的“文学本位”观念。