Vertices Contained in all or in no Minimum Paired-Dominating Set of a Tree

A set S of vertices in a graph G is a paired-dominating set of G if every vertex of G is adjacent to some vertex in S and if the subgraph induced by S contains a perfect matching. We characterize the set of vertices of a tree that are contained in all, or in no, minimum paired-dominating sets of the tree. Research supported in part by the South African National Research Foundation and the University of KwaZulu-Natal.     

A Polynomial Time Approximation Scheme for the Problem of Interconnecting Highways

The objective of the Interconnecting Highways problem is to construct roads of minimum total length to interconnect n given highways under the constraint that the roads can intersect each highway only at one point in a designated interval which is a line segment. We present a polynomial time approximation scheme for this problem by applying Arora's framework (Arora, 1998; also available from http:www.cs.princeton.edu/~arora). For every fixed c > 1 and given any n line segments in the plane, a randomized version of the scheme finds a -approximation to the optimal cost in O(n ^O(c)log(n) time.     

A 75° Angle Constraint for Plane Minimal T1 Trees

In this paper it is shown that the minimum angle between any 2 edges of an Euclidean plane minimal T1 tree, or 3-size Steiner tree, is at least 75°.     

基于利率风险的保险公司资产负债管理研究

应用无套利分析方法和二叉树方法对退保期权进行了定价,使用数值方法得到了中国市场的三次多项式利率期限结构模型,并应用以上结果建立了基于利率风险的久期缺口免疫模型,并使用保险公司实际资产负债数据对模型效果进行了检验。     

Adaptive Flood Risk Management Under Climate Change Uncertainty Using Real Options and Optimization

It is well recognized that adaptive and flexible flood risk strategies are required to account for future uncertainties. Development of such strategies is, however, a challenge. Climate change alone is a significant complication, but, in addition, complexities exist trying to identify the most appropriate set of mitigation measures, or interventions. There are a range of economic and environmental performance measures that require consideration, and the spatial and temporal aspects of evaluating the performance of these is complex. All these elements pose severe difficulties to decisionmakers. This article describes a decision support methodology that has the capability to assess the most appropriate set of interventions to make in a flood system and the opportune time to make these interventions, given the future uncertainties. The flood risk strategies have been explicitly designed to allow for flexible adaptive measures by capturing the concepts of real options and multiobjective optimization to evaluate potential flood risk management opportunities. A state‐of‐the‐art flood risk analysis tool is employed to evaluate the risk associated to each strategy over future points in time and a multiobjective genetic algorithm is utilized to search for the optimal adaptive strategies. The modeling system has been applied to a reach on the Thames Estuary (London, England), and initial results show the inclusion of flexibility is advantageous, while the outputs provide decisionmakers with supplementary knowledge that previously has not been considered.     

基于模糊二叉树模型的高速公路投资项目价值评估

高速公路项目投资价值评价是一个非常复杂的问题,而传统的评价方法大多依赖于对未来变量的估计,而这种估计大多具有模糊性。针对高速公路项目投资的特点,深入分析高速公路项目评价中的不确定性因素,利用模糊数表示未来收入的上升和下降幅度,进而建立模糊二叉树模型。实证分析表明投资者可以通过不断调整高速公路未来收入变化的模糊数的左右边界等变量,逐步调整其对未来收入的变化预期,从而合理估计高速公路投资项目的价值。     

“树”与“楼”——台湾女性诗作中“女性经验”的一个成长维度

“女性经验”是台湾女性诗人诗歌成长的一个空间,譬如“树”和“楼”意象就是这个空间中一个典型的经验维度。在这个空间里,女性找到了提升自我的凭借,也回应了社会对她们的压制,她们在不同的“经验”之路上,把记忆与希望都放大到了和男性强势话语相提并论的起点上,给自己也给了世界一个探究当代台湾文化一个重要窗口。     

基于功能结构树的数控磨床可靠性研究

基于功能结构树,根据某数控磨床的故障数据,对其故障部位及故障原因进行了分析。针对发生故障率较高的子系统———高频电主轴进行深入研究,找出其故障发生的主要原因是元器件烧坏,提出了相应的可靠性改进措施,为数控磨床的可靠性设计和分析提供了依据。     

度约束欧氏Steiner最小树问题及其求解

在欧氏Steiner最小树的基础上，对每个正则点加上了度约束限制，提出了度约束欧氏Steiner最小树问题，分析了该问题的特性，给出了该问题的模拟退火和蚂蚁算法求解过程，并使用Delphi语言编程，在Windows XP平台上运行通过．通过大量算例的计算结果验证了该问题的实用性及算法的有效性．     

Understanding the experience of stressors: The use of sequential analysis for exploring the patterns between various work stressors and strain

The availability of traditional self-report instruments for measuring work stressors may have diverted attention from exploring the way in which different stressors relate to one another. In order to develop a better understanding of the nature of the stressor experience a study was undertaken to explore the stressor-strain relationship using sequential tree analysis, a stepwise procedure that provides a “visual display” of the patterns and associations between stressors and strains. The study employed a sample of 695 principals and deputy principal teachers of secondary schools in New Zealand, who received a questionnaire measuring stressors and strains. SPSS AnswerTree® (version 2.0.1) was used to identify the patterns of association. The patterns of stressors that emerge from this analysis were used in a didactic or illustrative way to identify issues of measurement that may need to be resolved in order to derive a better understanding of the stressor experience. Different stressor patterns were associated with different levels of, but lower levels of strain were not simply the obverse of those stressors that cause higher levels of strain. Two not mutually exclusive issues emerge from the results, suggesting that stressor measurement practices may need to be reviewed. The first includes structural level issues such as considering the number, type, and potency of different stressors. The second includes issues best described as conditions of association. These concern understanding why different stressor patterns form, the relationship between stressors in those patterns, and the potency of patterns.