一类非线性混合整规划的无约束连续化解法

将整系数多项式 0 - 1混合整规划问题化成无约束多项式规划问题。通过解该问题 ,能得到原问题的近似解。处理方法的特点是能够直接处理不等式约束情形 ,而不需要先将不等式约束化成等式约束再来处理     

Any complete preference structure without circuit admits an interval representation

This article proves that all complete preference structures where the strict preference relation (P) has no circuit admit a representation by intervals of the real line; the rule for deciding whether an interval is indifferent or preferred to another is less straightforward than for interval orders: strict preference is indeed compatible with a certain degree of overlapping of intervals, the allowed degree being specified by means of a so-called tolerance function.     

De minimis and equity in risk

Indices and orderings are developed for evaluating alternative strategies in the management of risk. They reflect the goals of reducing individual and collective risks, of increasing equity, and of assigning priority to the reduction and to the equity of high risks. Individual risk is defined as the (random or non-random) level of exposure to a danger. In particular the role of a lower negligibility level is investigated. A class of indices is proposed which involves two parameters, a negligibility level and a parameter of inequality aversion, and several interpretations of the indices are discussed. We provide a set of eight axioms which are necessary and sufficient for this class of indices, and we present an approach to deal with partial information on the parameters.     

A fast splitting procedure for classification trees

This paper provides a faster method to find the best split at each node when using the CART methodology. The predictability index 018/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0"> is proposed as a splitting rule for growing the same classification tree as CART does when using the Gini index of heterogeneity as an impurity measure. A theorem is introduced to show a new property of the index 018/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0">: the 018/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0"> for a given predictor has a value not lower than the 018/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0"> for any split generated by the predictor. This property is used to make a substantial saving in the time required to generate a classification tree. Three simulation studies are presented in order to show the computational gain in terms of both the number of splits analysed at each node and the CPU time. The proposed splitting algorithm can prove computational efficiency in real data sets as shown in an example.     

大型供应链设计的基本数学模型与算法研究

随着信息技术与全球经济一体化的发展,供应链管理成为全球管理科学的研究热点。本文在分析国内外各种关于供应链设计的数学模型与算法的基础上,提出了具有普遍性意义且简单易行的MIP供应链设计的数学模型以及求解供应链问题的有界变量广义上界算法。实例计算表明,提出的模型和方法是可靠实用的。     

Mixed integer (0–1) fractional programming for decision support in paper production industry

This paper presents an effective and efficient method for solving a special class of mixed integer fractional programming (FP) problems. We take a classical reformulation approach for continuous FP as a starting point and extend it for solving a more general class of mixed integer (0–1) fractional programming problems.To stress the practical relevance of the research we focus on a real-life application in paper production industry. The constantly advancing physical knowledge of large scale pulp and paper production did have a substantial impact on an existing DSS in which mixed integer (0–1) fractional programming is introduced. We show that the motivation to solve a real-life fractional programming problem can provide the basis for a new approach in a new context that has an added value of its own, even outside the given application area. We describe the main characteristics of the DSS, the necessity to develop a non-iterative solution procedure and demonstrate both the effectiveness and efficiency of the proposed approach from practical data sets.     

Travailler ou ne pas travailler: la motivation professionnelle autre que pécuniaire et ses prédicteurs,une question d'époque

Pour mesurer la motivation professionnelle autre que pécuniaire, on demande généralement aux gens s'ils continueraient à travailler s'ils gagnaient au loto. Les auteurs rappellent les conclusions des études menées sur la base des réponses à cette question dans différents pays dont Israël, tout en recherchant l'influence en la matière des variables démographiques et des différentes dimensions du sens du travail. Ils constatent un net recul de la motivation professionnelle autre que pécuniaire au nouveau millénaire, et une évolution des facteurs en cause. Ils analysent ces résultats et leurs effets potentiels sur le travail et l'emploi au regard de l'évolution économique et sociale en Israël.     

Reinvigorating the social contract and strengthening social cohesion: Social protection responses to COVID-19

The COVID-19 pandemic has exposed the vulnerability of those who are inadequately covered by social protection in more and less developed countries alike, and has exacerbated the fragility of a social contract that was already under strain in many countries. A weak social contract in the context of an exceptional crisis poses a very real risk to social cohesion. Nevertheless, many States have reasserted themselves as the guarantor of rights by protecting public health and incomes. By sustaining these measures, economic recovery will be supported which will help minimize risks that may weaken social cohesion. However, this is a fast-moving, inherently unstable and protracted crisis. Social protection stands at a critical juncture. Decisive policy action will be required to strengthen social protection systems, including floors, as one of the cornerstones of a reinvigorated social contract.