可拓市场的类型与实现方式研究

根据可拓市场的概念，探讨了在不同可拓变换下可拓市场的类型及实现可拓市场的方式。这些研究为企业开拓市场提供了有效的形式化方法。     

New Tractable Classes From Old

The constraint satisfaction problem is known to be NP-hard in general, but a number of restrictions of the problem have been identified over the years which ensure tractability. This paper introduces two simple methods of combining two or more tractable classes over disjoint domains, in order to synthesise larger, more expressive tractable classes. We demonstrate that the classes so obtained are genuinely novel, and have not been previously identified. In addition, we use algebraic techniques to extend the tractable classes which we identify, and to show that the algorithms for solving these extended classes can be less than obvious.     

几何设计约束的表示与满足问题研究

对于智能ＣＡＤ系统来说，具有解决几何设计约束的功能是重要的。本文提出了一种面向对象的几何设计约束表示方法，它可以通过两种方式来表达。文中给出了一个约束传播算法，用于解决约束满足问题。     

Constraint Databases: Promising Technology or Just Intellectual Exercise?

This paper describes the state of Constraint Databases (CDBs), a young discipline at the intersection of Database Management, Constraint Programming, Computational Geometry and Operations Research. As in Constraint Logic Programming, constraints in CDBs are a first class data type, and can play many modeling roles including spatial and temporal behavior, complex design requirements, and partial and incomplete information, for which existing databases have proven inadequate. We motivate the importance of CDBs, outline the work in the area that has been done, the current trends, and future directions and challenges. We briefly discuss (1) constraint modeling, canonical forms and algebras, (2) data models and query languages, (3) indexing and approximation-based filtering, (4) constraint algebra algorithms and global optimization, and (5) systems and case studies. We argue that CDBs are a promising technology that will impact many important application realms, and furthermore have the potential to be integrated into future database systems, and operations research and constraint programming tools.     

Effects of crack size and weld metal mismatch on the has cleavage toughness of wide plates

The heat affect zone (HAZ) is in many cases considered to be the most critical part of a weldment. In this paper, the effect of crack size and weld metal mismatch on the HAZ cleavage toughness of wide plate specimens with X-groove has been investigated by the J-Q-M theories and a simple micromechanism for cleavage fracture. Two crack sizes have been studied (a/w = 0.1 and 0.3). In the analyses, the HAZ yield strength is assumed to be higher than the base metal. For each crack size, weld metal local overmatch and local evenmatch with respect to the HAZ are considered. For a given global strain, the results indicate that weld metal overmatch and evenmatch yield the same crack tip loading in terms of J-integral for a/w = 0.3. For a/w = 0.1, overmatch gives lower crack tip loading than evenmatch. For a given crack tip loading, weld metal local evenmatch in general results in less effective crack tip loading than the overmatch. Overmatch is detrimental to HAZ toughness, but this detrimental effect becomes less significant when the crack size decreases.     

认真创建服务型企业拓展老水电厂发展空间——湖北省白莲河水力发电厂发展问题的思考

根据对白莲河电厂历史的与现状的分析,提出该厂应当由生产型向服务型转变,在服务中提高职工素质,拓展老水电厂的发展空间.     

后桥壳的可靠性优化设计

该文讨论了后桥壳的可靠性优化设计问题.在基本随机变量的概率特性已知的情况下,应用随机摄动法和约束随机方向法对后桥壳进行可靠性优化设计,并编制了实用的计算机程序,可以迅速准确地得到后桥壳的可靠性设计参数.     

一族Liouville可积系及其双约束流的Hamilton系统

构造了Loop代数 A2的一个子代数,由此建立了一个3×3等谱问题,由屠规彰格式得到了一族Liouville意义下的可积Hamilton方程族。通过建立双对称约束,得到了该方程族的两组约束流,并将其化为广义Hamilton系统。     

示例学习的扩张矩阵理论

本文提出示例学习的一种计算理论,扩张矩阵论.根据这个理论,示例学习中一些主要最优化问题被证明是NP难题,并给出这些难题的近似解法及下界的估计.     

分流液压转向牵引计算的展开图及其应用

本文论及分流液压转向牵引计算的概念,方法及其展开图,并且提供了计算机绘制的展开图和应用实例。