区间三角模糊多属性决策的GRA扩展方法

针对属性权重信息部分己知且属性值以区间三角模糊数形式给出的多属性决策问题,提出了一种基于灰色关联分析(GRA)扩展的决策方法.首先给出了区间三角模糊数的定义,然后依据传统GRA法的基本思想建立了区间三角模糊数多属性决策问题的决策步骤.最后给出了一个实例分析,所得结果表明了方法的实用性和可行性.     

“普适发展判据"对热弹性材料的适用条件

本文研究了普适发展判据对热弹性材料的本构限制,证明了该判据对热弹性材料适用的充要条件是机械变形与热传导互不耦合,因此一般情形下该判据对热弹性材料不能适用。     

Quasi-steady regimes of wave propagation in active mixtures

Regimes of multifront, spinning, marginal, and galloping detonation, quasi-detonation, and supersonic and subsonic (turbulent and laminar) flames are discussed. Criteria for identification of different wave regimes include not only the wave velocity or its deficit, but also the relation between the cell size (or the size of the induction zone) and the characteristic size of equipment. New applications of detonation and combustion are also discussed. This paper is based on an invited presentation at the 21st International Colloquium on the Dynamics of Explosions and Reactive Systems, Poitiers, France, July 23–27, 2007.     

A Stepwise Assessment of Parsimony and Fuzzy Entropy in Species Distribution Modelling

Entropy is intrinsic to the geographical distribution of a biological species. A species distribution with higher entropy involves more uncertainty, i.e., is more gradually constrained by the environment. Species distribution modelling tries to yield models with low uncertainty but normally has to reduce uncertainty by increasing their complexity, which is detrimental for another desirable property of the models, parsimony. By modelling the distribution of 18 vertebrate species in mainland Spain, we show that entropy may be computed along the forward-backwards stepwise selection of variables in Logistic Regression Models to check whether uncertainty is reduced at each step. In general, a reduction of entropy was produced asymptotically at each step of the model. This asymptote could be used to distinguish the entropy attributable to the species distribution from that attributable to model misspecification. We discussed the use of fuzzy entropy for this end because it produces results that are commensurable between species and study areas. Using a stepwise approach and fuzzy entropy may be helpful to counterbalance the uncertainty and the complexity of the models. The model yielded at the step with the lowest fuzzy entropy combines the reduction of uncertainty with parsimony, which results in high efficiency.     

一类无穷小(大)量的判别法及其应用

将级数敛散性判别法中的D’Alembert和Cauchy判别法移植到无穷小(大)数列上,可得到关于无穷小(大)数列的D’Alembert和Cauchy判别法,从而解决无穷小(大)数列的判别问题.     

On the exactness of the ε-constraint method for biobjective nonlinear integer programming

The ε-constraint method is a well-known scalarization technique used for multiobjective optimization. We explore how to properly define the step size parameter of the method in order to guarantee its exactness when dealing with biobjective nonlinear integer problems. Under specific assumptions, we prove that the number of subproblems that the method needs to address to detect the complete Pareto front is finite. We report numerical results on portfolio optimization instances built on real-world data and show a comparison with an existing criterion space algorithm.     

A porosity-dependent inelastic criterion for engineering materials

Many criteria have been developed to describe the yielding condition, plastic potential, and failure strength of engineering materials. In this paper, the authors first review the characteristics of a few of the more common criteria used for porous materials. It is then shown that the main features of many criteria can be represented by a unique set of recently developed equations. The ensuing multiaxial criterion becomes applicable to a variety of materials and loading states. One of the advantages of the proposed criterion, named MSDP_u, is that it is explicitly porosity-dependent. The validity of this general inelastic criterion is demonstrated using experimental results obtained from various types of materials. A brief discussion follows on the advantages and limitations of the proposed equations.     

土工织物防护工程反滤准则试验研究

土工合成材料的出现,为岩土工程施工技术带来了重要的影响。但将土工合成材料应用在堤岸防护工程中所出现的一些问题还有进行深入科学研究的必要。尤其是保土性准则一直是研究的热点问题。本文结合较大孔径织造布在堤岸防护工程中多年应用实践,通过室内反滤试验,野外淘刷试验及工程应用实例分析研究,提出了O90≤（2¹0）d90防护工程中织造布保土性设计新准则,突破了目前普遍采用的O90≤（1²）d90设计指标。     

巷道围岩稳定性的判据及岩石分类

本文通过套筒致裂法测试巷道围岩应力及力学性质,并以此进行围岩稳定性分析和分类;提出了巷道围岩稳定性判据以及巷道围岩分类的原则;介绍了本稳定性分析方法在若干煤矿巷道围岩及立井井壁应力测试地点的应用。     

对包装用缓冲材料动态压缩试验法的讨论

对国标包装用缓冲材料动态压缩试验方法(GB8167-87)进行了剖析，发现了两个较大的缺陷．为了更好而全面地了解材料的缓冲特性，完善国标GB8167-87，提出了两套缓冲材料动态压缩试验方法，作为对GB8167-87有益的改进和补充．并利用这两种方法对木材这种广泛应用的包装材料的动态缓冲特性进行了实验研究，得到了木材动态缓冲特性．