Optimal Solutions for the Temporal Precedence Problem

Abstract. In this paper we refer to the Temporal Precedence Problem on Pure Pointer Machines . This problem asks for the design of a data structure, maintaining a set of stored elements and supporting the following two operations: insert and precedes . The operation insert (a) introduces a new element a in the structure, while the operation precedes (a,b) returns true iff element a was inserted before element b temporally. In [11] a solution was provided to the problem with worst-case time complexity O (log log n ) per operation and O(n log log n) space, where n is the number of elements inserted. It was also demonstrated that the precedes operation has a lower bound of Ω (log log n ) for the Pure Pointer Machine model of computation. In this paper we present two simple solutions with linear space and worst-case constant insertion time. In addition, we describe two algorithms that can handle the precedes (a,b) operation in O (log log d ) time, where d is the temporal distance between the elements a and b .     

混凝土结构非线性全过程分析中的迭代控制法研究

在深入研究各类迭代控制法的基础上，针对混凝土结构的非线性全过程分析，在常规的位移和弧长控制法中引入了简单适用的考虑路径搜寻和单因加速的方法，明显改善了收敛情况。     

从数据结构角度设计导游系统

从数据结构角度为旅游胜地设计导游系统。向游人提供景点的信息查询服务,根据指定的景点提供相关的景点信息。任意给定起点和终点,查询两点之间的最短路径。     

梁架独特的金代朔州崇福寺观音殿

金代朔州崇福寺观音殿是具有典型厅堂型建筑特征的金代佛寺建筑之一，其地盘形式采用减柱造，将前金柱四根全部减掉，形成了此殿特殊的双重人字叉手梁架形制。     

膜结构裁剪膜片展开的二次测地线法

本首先对目前应用较广的膜结构裁剪方法，即裁剪线生成与图形展开的方法进行了比较研究，并在此基础上提出了一种新的裁剪方法——二次测地线法．通过对有理论解算例的分析及对不同形式的膜结构进行裁剪，验证了本方法的正确性、可靠性及广泛适用性．     

Economic Model to Optimize Underground Utility Protection

The need for better protecting our vital infrastructure from being damaged or destroyed has received increased attention since the terrorist attacks on September 11, 2001. The tragedy of having thousands of innocent people die before the eyes of an entire nation awakened people to the reality of “managed” attacks of unthinkable magnitudes. However, tragedies of a smaller scale are a daily occurrence but accepted as “collateral damage” of work in an unsafe environment. This paper presents a cost-benefit analysis to address the question of how much money should be spent in protecting underground utilities from damage. During the study of an actual incident it was found that the total costs of such accidents are vastly underreported because only costs for emergency responses and repair are tallied up. This paper makes the case that a comprehensive approach for assessing the total economic impact of such incidents on the public, business, and government is the critical stepping stone to a mathematical optimization of expenditure for damage prevention. In addition, the reader will quickly realize that the use of the presented optimization model provides theoretical underpinning for the engineering profession in its effort to better protect our critical infrastructure from terrorist attacks.     

Delamination Analysis for Laminated Composites. II: Numerical Verification

A validation of the delamination analysis models developed in a companion paper is provided through comparisons of predictions with finite‐element and elasticity solutions. The models are applied to the analysis of composite compression specimens reinforced with end tabs. An elasticity solution for the gage section of the specimens is developed. A comparison of the characteristic roots shows that the predictions of the models include the material and geometric parameters that control the behavior, and the roots corresponding to the basic stretching and bending modes are accurately predicted. The stress distribution at the interface between tabs and specimen is in good agreement with a finite‐element simulation. The interlaminar shear and peel stresses show an exponential increase with a maximum intensity at the free edges of the tabs. The behavior of previously tested specimens is explained; and practical guidelines for specimen design are provided to avoid unwanted extraneous modes of failure. The influence of the deformation modes associated with each model is investigated. An assessment of the accuracy and level of complexity is presented.