随机需求下基于供应中断的备份供应商决策分析

假定需求服从随机分布,研究由零售商主导的供应链中,采用一个战略供应商和一个备份供应商模式,零售商与备份供应商通过能力期权建立订货契约:首先,零售商向备份供应商预订能力,支付预订成本;接着,向战略供应商订货,如果没有发生突发事件则其供货量等于订货量,否则供货量变为零;然后,零售商基于战略供应商的供货量和备份供应商的能力预订确定向备份供应商的订货量,支付执行成本;最后,零售商用战略供应商和备份供应商的总供货量满足顾客需求。备份供应商在考虑自己的能力维持成本和制造成本后决定是否接受零售商提供的能力期权契约。针对零售商可选择的四种不同策略,求得采取不用策略所满足的条件,并给出相应的最优订货量、能力预订量和能力执行量和最优利润等的解析解。     

Models for 1-out-of Q systems with stochastic lead times and expedited ordering options for spares inventory

The purpose of this article is to develop two kinds of continuous-time cyclic inventory models with stochastic lead times and expedited ordering options. The order form under consideration is similar to that arising in the spare part inventory management. Especially, the control problem to determine the timing for the regular order is considered, and the optimal policy which minimizes the long-run average cost is analytically characterized. Finally, numerical examples are presented to evaluate the uncertainty of stochastic lead times, and the optimal inventory policy, which is composed of both the ordering time and the order quantity, is numerically calculated.     

Convex ordering criteria for Lévy processes

Modelling financial and insurance time series with Lévy processes or with exponential Lévy processes is a relevant actual practice and an active area of research. It allows qualitatively and quantitatively good adaptation to the empirical statistical properties of asset returns. Due to model incompleteness it is a problem of considerable interest to determine the dependence of option prices in these models on the choice of pricing measures and to establish nontrivial price bounds. In this paper we review and extend ordering results of stochastic and convex type for this class of models. We also extend the ordering results to processes with independent increments (PII) and present several examples and applications as to α-stable processes, NIG-processes, GH-distributions, and others. Criteria are given for the Lévy measures which imply corresponding comparison results for European type options in (exponential) Lévy models.     

An MCDM model for media selection in the dual consumer/industrial market

An optimal advertising media selection is a strategic factor for the operations of both traditional and e-business environments. This paper presents a case study that considers two options: industrial and consumer products. In order to resolve the strategic decision-making about dual market high technology products, a mixed integer goal programming model is developed to facilitate the advertising media selection process.Preemptive priority ordering is established by the analytic hierarchy process. The problem is solved lexicographically using a software package, based on the data obtained from the e-business industry in Korea. The satisfying solution is identified and analyzed, and sensitivity analyses are performed for model flexibility.     

NBU(2)性的偏序刻画

为刻画同一寿命分布类中两个不同分布的NBU(2)性的强弱,本文定义了一个新的偏序,即NBU(2)序,并证明NBU(2)序具有反身性,反对称性和传递性.另外,该偏序与超可加序、NBUE序,增凹序的关系也作了探讨.基于被比较分布是指数的情况,还建立了判定NBU(2)序的一个充要条件.     

关于矩阵的奇异值偏序

研究矩阵的奇异值偏序,给出了矩阵的奇异值偏序的等价刻画和性质,指出了相关文献关于矩阵*序刻画不真,利用强同时奇异值分解给出了矩阵*-序的刻画.     

Review and comparison of three methods for the solution of the car sequencing problem

The car sequencing problem is the ordering of the production of a list of vehicles which are of the same type, but which may have options or variations that require higher work content and longer operation times for at least one assembly workstation. A feasible production sequence is one that does not schedule vehicles with options in such a way that one or more workstations are overloaded. In variations of the problem, other constraints may apply. We describe and compare three approaches to the modeling and solution of this problem. The first uses integer programming to model and solve the problem. The second approaches the question as a constraint satisfaction problem (CSP). The third method proposes an adaptation of the Ant Colony Optimization for the car sequencing problem. Test-problems are drawn from CSPLib, a publicly available set of problems available through the Internet. We quote results drawn both from our own work and from other research. The literature review is not intended to be exhaustive but we have sought to include representative examples and the more recent work. Our conclusions bear on likely research avenues for the solution of problems of practical size and complexity. A new set of larger benchmark problems was generated and solved. These problems are available to other researchers who may wish to solve them using their own methods.     

On ranking fuzzy sets

A mathematical model describing a fuzzy ordering of fuzzy sets is suggested. In this model an induced fuzzy ordering is defined as the inverse image of the natural linear ordering on real numbers under natural fuzzy correspondence between fuzzy sets and real numbers. The transitivity property of the strict fuzzy ordering associated with the induced fuzzy ordering is established.     

An optimal ordering policy for a spare unit with lead time

We consider a generalised ordering policy in which a spare unit for replacement can be delivered only by order after a constant lead time. Introducing the costs for ordering, shortage and holding, we derive the expected cost per unit time in the steady-state. We discuss the optimal ordering policy which minimises the expected cost, and show in a main theorem that the optimal policy is reduced to either one of two typical ordering policies depending on some conditions. We further discuss a similar ordering policy with varying lead times.     

关于DMRL序及其相关序的若干性质

证明了DMRL偏序关系在平移和尺度变换下的不变性,并获得了一个充分必要条件.同时考虑了DMRL序与IFR及IFRA序之间的关系.     

可换BCH-代数

引入了可换BCH-代数的概念,给出了可换BCH-代数的两个充要条件.对偏序可换BCH-代数进行了讨论,给出了偏序BCH-代数是可换的两个充要条件.证明了偏序可换BCH-代数的每个分支是一个下半格,局部有界偏序可换BCH-代数的每个分支是一个格.     

A group majorization ordering for Euclidean distance matrices

This paper investigates some properties of Euclidean distance matrices (EDMs) with focus on their ordering structure. The ordering treated here is the group majorization ordering induced by the group of permutation matrices. By using this notion, we establish two monotonicity results for EDMs: (i) The radius of a spherical Euclidean distance matrix (spherical EDM) is increasing with respect to the group majorization ordering. (ii) The larger an EDM is in terms of the group majorization ordering, the more spread out its eigenvalues are. Minimal elements with respect to this ordering are also described.     

Full ordering in the Shorrocks mobility sense of the semiring of monotone doubly stochastic matrices

In this paper, we investigate the ordering on a semiring of monotone doubly stochastic transition matrices in Shorrocks’ sense. We identify a class of an equilibrium index of mobility that induces the full ordering in a semiring, while this ordering is compatible with Dardanoni’s partial ordering on a set of monotone primitive irreducible doubly stochastic matrices.     

Partial orderings of matrices referring to singular values or eigenvalues

A new partial ordering in the set of complex matrices is defined, which is weaker than the star ordering introduced by Drazin in 1978 and stronger than the minus ordering introduced by Hartwig in 1980. This ordering refers to singular values of matrices, and the interest in it was generated by canonical interpretations of the minus and star orderings, given by Hartwig and Styan in 1986. For Hermitian matrices, a similar ordering referring to eigenvalues is also considered, and its connection with a problem concerning distributions of quadratic forms in normal variables is pointed out.     

Ordering fuzzy sets over the real line: An approach based on decision making under uncertainty

The ordering of fuzzy sets over the real line is approached from the point of view of ordering intervals rather than ordering numbers. First, the maximax and maximin criteria which are commonly used for ordering intervals are expressed in terms of characteristic functions. These criteria and the Hurwicz criterion for decision making under complete ignorance are then reformulated in a manner that allows for their generalization to the fuzzy case. Transitivity is established for these ordering rules. A criterion based on the principle of diminishing marginal utility is also presented.     

三条路并的极值能量及一类图的能量排序

拟序是图能量排序中一种有效方法,基于该方法,已经得到了大量图类的极值能量排序的结果.Gutman给出了点数和为n的两条路的并的能量排序,而三条路的并的能量排序没有一个理想的结论.本文利用拟序法给出点数和为n的三条路的并的极值能量及一类图能量的排序.     

The failure rate and likelihood ratio orderings of standby redundant systems

There are various notions of partial ordering between lifetimes of systems; stochastic ordering, failure rate ordering, and likelihood ratio ordering. In this paper we show that for series systems with noni.i.d. exponential lifetimes of components, standby redundancy at component level is better than that at system level in failure rate ordering and likelihood ratio ordering. We also demonstrate that for 2-component parallel systems withi.i.d. exponential lifetimes of components, standby system redundancy is better than standby component redundancy in failure rate ordering and likelihood ratio ordering.     

两类供应风险下装配商的最优订购策略

针对两类供应风险(不确定产能与随机产出率)下装配制造商的零部件订购决策这一难题,运用随机非线性规划方法,以装配商期望利润最大化为目标,建立零部件订购决策的多维优化模型,刻画了确定需求下的最优订购量,并对其进行了灵敏性分析。最后,通过数值算例验证了模型结论并进一步探讨不同类供应风险的影响,为装配商的零部件订购决策和风险管理提供有益的管理启示。     

态射集中的加权星序和加权广义逆

本文推广范畴上态射集中的星序理论.引进范畴上态射集中的加权星序.利用态射集的加权广义逆来刻划态射集中的加权星序.给出了态射集中的加权星序和态射的加权广义逆之间的一些关系.得到了态射集中的加权星序的一些刻划和性质.     

Some fuzzy stochastic orderings for fuzzy random variables

A new approach to stochastic ordering of fuzzy random variables is investigated in this paper. The traditional definitions of stochastic ordering, hazard rate ordering, and also mean residual life ordering were extended and proposed the unified indexes to ranking fuzzy random variables. Finally, we study the stochastic ordering of fuzzy order statistics by using our proposed approach and established some properties.