基于复杂网络的非正式团体知识交互网络分析

针对知识在非正式团体中的传播特征,结合复杂网络理论,为了企业知识不断创新,提出了一种非正式团体知识交互网络模型.通过仿真得出,在小世界网络模型下知识的传播速度和平均知识水平比其他网络模型有明显优势,进而在非正式团体知识交互网络的描述与分析中提出利用"小世界"的平均路径长度和聚类系数来表征IFG知识交互网络中的交互频繁度和交互聚集度的思想,为进一步研究IFG组织及管理与其内部知识创新的内在联系提供了数量分析基础.     

HClO对贻贝粘附单元DOPA氧化的理论研究

采用量子化学密度泛函理论(DFT)研究贻贝粘附单元DOPA(3,4-二羟基苯丙氨酸)的结构与性质,得分子的几何构型、原子电荷分布、反应活性及热力学等参数,表明:DOPA苯环易与HClO(次氯酸)发生亲电取代反应(1),生成3-氯4,5-二羟基苯丙氨酸,阻碍生成贻贝内超强粘附单元DOPA二联体,降低粘附蛋白间粘性;DOPA侧链易与HClO发生亲电亲核反应(2),促使DOPA侧链的断裂,降低粘附蛋白内粘性;在相同温度下,反应(1)和反应(2)的△G<0,且△G(1)<△G(2),反应(1)较易发生.     

环氧乙烷于控制保险粉合成中的副反应

采用密度泛函理论B3LYP法及自恰等密度PCM模型,在6-311G(d)基组条件中研究环氧乙烷在保险粉生产中参加的主要反应,系统论证环氧乙烷的去向.本文首先分析环氧乙烷于控制硫代硫酸钠含量的热力学、动力学基础及体系中各亲核试剂的反应活性,然后分析环氧乙烷各主要反应的比例关系.理论计算结果与实验结论一致,即硫代硫酸钠消耗的环氧乙烷最多(71.5%),其次是水(17.5%),甲醇(5.0%),亚硫酸氢钠(1.3%).     

A piecewise analysis method to stability analysis of linear continuous/discrete systems with time‐varying delay

The delay‐dependent stability problem of linear continuous/discrete systems with time‐varying delay is investigated based on a piecewise analysis method (PAM). In the method, the variation interval of the time delay is firstly divided into several subintervals. By checking the variation of the Lyapunov functional in every subinterval, some new delay‐dependent stability criteria are derived. Several numerical examples show that our method can lead to much less conservative results than those in the existing references. Moreover, when the number of the divided subintervals increases, the corresponding criteria can provide an improvement on the results. Copyright © 2008 John Wiley & Sons, Ltd.     

Stability analysis of neutral systems with mixed delays

The stability of neutral systems with mixed delays is studied in this paper. A new discretized Lyapunov functional method is proposed. The method in this paper is less conservative than the existing ones and the results are very close to the analytical results. In addition, this method allows the coefficient matrix of the neutral term to have time-varying uncertainties.     

分层次的汉语功能块描述库构建分析

现有功能块分析器对于不同长度和不同结构功能块的分析性能研究表明,长的结构复杂的功能块正是功能块自动分析的难点所在。由此,我们设计了新的分层次的功能块体系,并从清华句法树库TCT中自动生成了新的功能块语料库。通过对新的功能块语料库长度分布、内部结构分布分析,以及与单层次功能块语料库的相互关系的研究,我们证实了新的分层次功能块描述体系具有结构简单、长度短且分布均匀的优良特点。这些性质对功能块分析器的性能提高将会有很大的帮助。     

Computing presentations for subgroups of polycyclic groups and of context-free groups

Algorithms for solving uniform decision problems for algebraic structures crucially depend on the chosen finite presentations for the structures under consideration. Rewriting techniques have been used very successfully to solve uniform decision problems, when the presentations considered involve finite, noetherian, and ()-confluent rewriting systems. Whenever the class of algebraic structures considered is closed under the operation of taking finitely generated substructures, then the algorithms for solving the uniform decision problems can be applied to the substructures as well. However, since these algorithms depend on the form of the presentations, this involves the task of constructing a presentation of a certain form for a substructure given a presentation of this form for the structure itself and a finite set of generating elements for the substructure.This problem, which has received a lot of attention in algebra, is here investigated from an algorithmic point of view. The structures considered are the following two classes of groups, which have been studied extensively before: the polycyclic groups and the context-free groups.Finitely generated context-free groups can be presented by finite, monadic, and -confluent string-rewriting systems. Due to their nice algorithmic properties these systems provide a way to effectively solve many decision problems for context-free groups. Since finitely generated subgroups of context-free groups are again contextfree, they can be presented in the same way. Here we describe a process that, from a finite, monadic, and -confluent string-rewriting system presenting a context-free groupG and a finite subsetU ofG, determines a presentation of this form for the subgroup U ofG that is generated byU. For finitely presented polycyclic groups we obtain an analogous result, when we use finite confluent PCP2-presentations to describe these groups.This work was performed while this author was visiting at the Fachbereich Informatik, Universität Kaiserslautern, during his sabbatical 1991/92     

相容剂控制高分子合金的形态与性能

应用相容剂可得到优质的“海岛”两相分散结构、分散相纤维化以及分散相层化两相分散结构,由此赋予共混体系高性能或高机能。相容剂在制备高性能或机能性高分子合金领域中日益起着重要的作用。     

A heuristic approach to automatic grasp planning for a 3-fingered hand

This paper presents the core of a software system able to determine a good grasp configuration on 3D objects for a three-fingered hand. The grasp planning problem has been studied considering both the constraints due to the stability and accessibility conditions, and the ones related to functionality. Physical, geometrical, spatial and task-related knowledge for solving the grasp planning problem have been properly modelled to support a heuristic-based reasoning process. A series of heuristic rules and geometric tests are used to scan the solution space, searching for a good grasp. In fact, when considering the three-dimensional case, a purely analytical and exhaustive approach appears too complex because of the dimension of the search space. This approach results in an incremental and modular model of grasp reasoning, that has been implemented using the Flex expert system shell. This work has been developed and demonstrated within the Esprit 2 project CIM-PLATO No. 2202.