模糊度量空间

首先给出了有广义度量空间的基本概念，为通常意义下的度量空间、随机度量空间、概率度量空间．．．等不同类型的“度量空间”，提供了一个统一的数学模型，并在该模型下给出了模糊度量空间的一个新定义，改进了文（４）和文（７）的工作。     

广义度量空间

本文主要内容有三：其一，继承和发展了Ｍｅｎｇｅｒ的基本思想，建立起广义度量空间的理论体系，给概率度量空间、随机度量空间以及模糊度量空间等，提供了一个统一的理论框架。改进了文［４］、［６］的工作。其二，站在广义度量理论的角度，对若干概率度量标准之间的关系进行了讨论，部分地回答了文［８］中提出的问题。其三，讨论了广义度量空间的拓扑结构以及完备化问题，推广了文［２］的工作。     

概率度量空间理论在中国的二十年

本文综述了我国二十年来在概率度量空间理论方面的研究成果 ,展望了以后可能的发展方向     

由一般拓扑度量空间所产生的Alignment空间

Alignment空间是一个在广义误差下定义的度量空间。在以往的信息处理问题中,一般只讨论离散状态下的序列比对Alignment问题,并由此产生一种新的非线性度量空间-Alignment空间。本文将离散状态下的Alignment空间推广到一般情况,得到了由一般拓扑度量空间所产生的Alignment空间仍然是度量空间,并证明了Alignment距离与Levenshtein距离的等价性。     

随机度量空间的压缩性质

研究了随机度量空间的三种压缩(概率压缩、随机压缩、度量压缩)的性质、随机Ekeland变分原理和Caristi不动点定理以及它们与完备性之间的相互关系。     

M—星形度量空间中的最佳逼近和不动点定理

在Ｍ－星形度量空间中研究最佳逼近的不动点定理，得到两个不动点定理和两个最佳逼近不动点的存在定理，该文的定理改进和推广了Ｍ．Ａ．Ａｌ－Ｔｈａｇａｆｌ等人的结果并概括一了些著名结果。     

度量空间压缩映象的拟Picard迭代收敛性定理

游兆永在概率度量空间中首次研究了拟Picard迭代,获得了四个收敛性定理。本文讨论了度量空间中压缩映象的拟Picard迭代,非常有趣的是,我们所得定理的证明应用了概率度量空间理论。 下面出现的φ和Ψ,我们总假定是[0,+∞)→[0,+∞)的严格递增的连续函数,且φ(t)0,t—(φ(t))→+∞(t→+∞)。     

模糊数空间中的一致收敛度量

讨论模糊数空间中一致收敛度量与其它常用度量之间的关系。和人们对模糊数空间的常识相反，本文中证明了的确一致收敛度量与其它度量之间有内在的联系。     

fuzzy度量空间的完备性与紧性

本文证明了文献[1]意义下的Fuzzy度量空间列紧的充要条件是既完备又全有界,文献[2,3]关于概率度量空间的主要结果是本文的特例。     

度量空间上的位势空间容量与Hausdorff测度

讨论了度量空间上的位势空间,并利用容量的概念建立其与Hausdorff测度之间的联系.     

Metrics for supply chain sustainability

Most interpretations of sustainable development recognise that there are constraints on long-term human activities imposed by material and energy availability and by the capacity of the planet to accommodate wastes and emissions; inter- and intra-generational equity within these constraints is then an ethical principle underlying sustainability. This leads to identifying three dimensions of sustainable development: techno-economic, ecological and social. This paper reviews the development of indicators to reflect these three dimensions, applicable to industrial sectors, companies and broad groups of products or services. Indicators of environmental and economic performance are relatively well established. They can be combined to indicate the sustainability of products, services and supply chains. Indicators of social performance are more problematic, particularly indicators to describe the social value of products and services. Cases from the process, petroleum and petrochemicals, electronics and fast moving consumer goods sectors are reviewed, showing that social indicators must be developed through public participation.     

Quantile-Based Metrics Applied to Process Performance

Commonly used metrics are usually evaluated under the assumption that the data have a more-or-less normal distribution. However, often the data are actually skewed. Some metric expressions evaluated under the normality assumption can contain substantial errors. Normality is a special case for distributions in general.

Standard statistical software packages will often automatically generate key quantile values sufficient to aid in expressions that properly characterize distributions and accurately evaluate performance metrics. This leads to better evaluation of incremental process improvements. This article shows how quantile-based metric evaluations can be applied to all process specification variables to assess their relative performance. Sample size calculations are also more accurate when quantile-based expressions are used.     

The MacWilliams Theorem for Two-Dimensional Modulo Metrics

In this contribution the MacWilliams theorem is stated for codes over finite fields with two-dimensional modulo metrics. Received June 17, 1994;revised version June 1, 1995     

机场噪声评价量分析与比较

分析世界主要国家和地区使用的机场噪声评价量的基本原理、计算方法及控制标准,并基于某大型繁忙机场实际噪声监测数据,通过实验分析论证各机场噪声评价量的共性和差异,指出现有机场噪声评价量的不完备和需改善之处。     

Using Hypertext Metrics to Measure Research Output Levels

Two common ways to measure the "output" of a researcher (or research group) are to count numbers of publications and to count the citations (references to these publications in publications of others). These simple methods are flawed because they cannot easily take into account the differences in publication and citation habits in different scientific communities.An alternative approach is to view citations as hypertext links, and to use or adapt hypertext metrics to compare the scientific output of researchers, in comparison to that of others in areas with similar publication and citation patterns. We show how hypertext metrics, introduced by Botafogo, Rivlin and Shneiderman, can be modified in order to identify comparable research fields based on their publication and citation pattern. An author's performance can then be compared to that of others in research fields with a similar pattern.     

对基于二次误差的模型简化方法的改进

模型简化在虚拟现实、模拟仿真等方面有着广泛的应用,但算法复杂、时间复杂度高一直是模型简化的主要问题。为了提高算法速度,沿用Garland提出的使用二次误差矩阵来简化三角面片模型的方法,使用八叉树空间分割的方法加速模型简化算法中用于进行边收缩的候选最近点对的排序过程,从而提高算法的速度。     

Impact characterization of RTM composites: Part I Metrics

The use of textile based architectures and the dry compaction of preform layers prior to resin infusion creates the potential for highly tailored resin transfer-moulded composites that have significantly different response to impact than traditional prepreg-based composites. The response of a number of resin transfer moulding (RTM) composites is characterized using both traditional and new metrics of performance. Impact performance maps are used to differentiate between materials response at a fundamental level and key differences are traced to differences in preform fabric architecture. Global and local differences in response based on architecture are elucidated through the determination of damage and energy absorbance, and are related to materials' specific characteristics in an attempt to allow comparison of impact response of composites on a more quantitative basis. This revised version was published online in November 2006 with corrections to the Cover Date.     

Producibility Analysis Using Metrics Based on Physical Process Models

This paper presents an approach to evaluating producibility which is intended to enhance the ability of engineers to quickly design low-cost and high-quality parts. We divide all production processes into two categories: trajectory-dominated processes in which a generic tool is moved in a trajectory to form the part shape, and process-physics-dominated processes in which shaped tools are used to form similarly shaped parts. We focus on process-physics-dominated processes and on producibility problems that arise because of part shape. We argue that for these processes the currently popular approach of representing parts as collections of geometric features may be inappropriate for evaluating producibility. We propose an alternative approach and representation. Our approach consists of first identifying the different failure modes of the process and then defining producibility metrics corresponding to the likelihood of encountering each failure mode. This set of metrics is used to represent the degree to which a part is easily manufactured. Finally, we demonstrate this approach by developing a set of metrics for evaluating the producibility of aluminum extrusions. We use extrusions from the Boeing 777 to validate the metrics.     

Evaluation Metrics for the Rating and Optimization of Snap-fits

Current snap-fit design guides recommend sizing snap-fit features on the basis of insertion force and allowable strain during assembly. Retention force information in such guides is often inaccurate, although this is considered to be the primary attribute of the snap-fit after assembly. The authors contend that these (insertion force, allowable strain, retention force) are not the only critical performance criteria for snap-fit features. Designers have to contend with several other constraints and design requirements. Additional performance metrics for snap-fit features are proposed by drawing upon considerable experience with plastic part design issues. Locking ratio, dimensional and volumetric retention force, consideration of the characteristic dimension of the joint and snap-fit, feature stiffness, required over-insertion and consideration of snap-fit strength relative to part strength are proposed to supplement currently used metrics for evaluating and rating snap-fit designs. The applicability of these metrics is illustrated with real-life examples, and their merits and demerits discussed. A chart of achievable locking ratios for different snap-fit topologies is presented for use as a design tool for the initial selection of snap-fit topologies. Its use as a rational basis for selection and optimization of snap-fits is suggested. Adoption of proposed metrics will allow designers to better quantify, and thereby optimize the performance of, snap-fit features. These ideas will be built upon in the future, and used as a basis for a comprehensive snap-fit selection and detailed design tool.