Flow equivalence and stochastic equivalence in G-networks

G-networks are novel product form queuing networks that, in addition to ordinary customers, contain unusual entities such as negative customers which eliminate normal customers, and triggers that move other customers from some queue to another. Recently we introduced one more special type of customer, a reset, which may be sent out by any server at the end of a service epoch, and that will reset the queue to which it arrives into its steady state when that queue is empty. A reset which arrives to a non-empty queue has no effect at all. The sample paths of a system with resets is significantly different from that of a system without resets, because the arrival of a reset to an empty queue will provoke a finite positive jump in queue length which may be arbitrarily large, while without resets positive jumps are only of size + 1 and they occur only when a positive customer arrives to a queue. In this paper we review this novel model, and then discuss its traffic equations. We introduce the concept of stationary equivalence for queueing models, and of flow equivalence for distinct queueing models. We show that the flow equivalence of two G-networks implies that they are also stationary equivalent. We then show that the stationary probability distribution of a G-network with resets is identical to that of a G-network without resets whose transition probabilities for positive (ordinary) customers has been increased in a specific manner. Our results show that a G-network with resets has the same form of traffic equations and the same joint stationary probability distribution of queue length as that of a G-network without resets.     

包含随机客户的选择性旅行商问题建模及求解

针对快递配送过程中客户需求具有不确定性的特征,提出一种新的路径优化问题——包含随机客户的选择性旅行商问题,在该问题中客户每天是否具有配送需求存在一定概率,并且对客户进行配送可获取一定利润。同时考虑以上两种因素,建立该问题的数学模型, 目标为在满足行驶距离限制的条件下,找出一条经过部分客户的预优化路径,使得该路径的期望利润最大。其可用于模拟构建最后一公里快递配送的路径问题,提供更具有经济效益的配送路径。随后提出包含精细化局部搜索策略的改进遗传算法,算法根据问题特点构建初始可行解。最后通过多个计算比对结果表明,该算法具有较高的计算效率。     

The effects of the availability of waiting-time information on a balking queue

We consider two balking queue models with different types of information about delays. Potential customers arrive according to a Poisson process, and they decide whether to stay or balk based on the available delay information. In the first model, an arriving customer learns a rough range of the current queue length. In the second model, each customer’s service time is the sum of a geometric number of i.i.d. exponential phases, and an arriving customer learns the total number of phases remaining in the system. For each information model, we compare two systems, identical except that one has more precise information. In many cases, better information increases throughput and thus benefits the service provider. But this is not always so. The effect depends on the shape of the distribution describing customers’ sensitivities to delays. We also study the effects of information on performance as seen by customers. Again, more information is often good for customers, but not always.     

带有负顾客的N策略工作休假M/M/1排队

考虑带有正、负顾客的N策略工作休假M/M/1排队。负顾客一对一抵消队尾的正顾客(若有),若系统中无正顾客,到达的负顾客自动消失,负顾客不接受服务。在休假期间,服务员并未完全停止工作而是以较低的服务率为顾客服务。用拟生灭过程和矩阵几何解方法,我们给出了稳态队长和稳态等待时间的分布。此外,我们也证明了稳态条件下的队长和等待时间的条件随机分解并得到了附加队长和附加延迟的分布。     

关系感知在银行业顾客忠诚形成中的中介机制研究

以银行业为背景,以顾客关系感知中的满意和信任为中介变量,建立企业形象、转换成本和服务质量三个典型营销要素影响顾客忠诚意向和忠诚行为的概念模型,并进行了实证检验.研究发现:企业形象、服务质量和转换成本会显著影响顾客忠诚行为,其中服务质量影响最大;顾客满意在企业形象和服务质量对顾客忠诚行为的影响中有不完全中介作用;信任在服务质量对顾客忠诚行为的影响中也有不完全中介作用.此外,顾客忠诚意向是营销要素影响顾客忠诚行为的重要中介变量.     

顾客为子树结构的树上反中心选址问题

顾客为子树结构的树上反中心选址问题是在树T上寻找一点(位于顶点处或在边的内部),使得该点与子树结构的顾客之间的最小赋权带加数距离尽可能地大.给出了该问题的一个有效算法,其时间复杂度为O(cn+sum from j=1 to m n_j),其中n_j为各子树T_j的顶点个数,c为不同的子树权重个数,n为树的顶点数.     

基于logit回归模型的顾客资产驱动因素与忠诚意向关系实证研究

国内关于顾客资产驱动因素模型的实证研究较少.将顾客资产三大驱动因素(价值资产、品牌资产和关系资产)与忠诚意向联系起来,用我国银行业688个数据进行了Logit回归建模,研究顾客资产驱动因素分别与忠诚意向之间的关系、驱动因素两两之间的关系以及顾客资产驱动因素组合对忠诚意向产生的协同效应.研究结论表明,首先,价值资产、品牌资产、关系资产均对顾客忠诚意向产生显著正影响;其次,品牌资产对关系资产和价值资产均产生显著正影响,但价值资产对关系资产的直接影响不显著,这可能是因为品牌资产在价值资产和关系资产之间的中介作用;最后,同时投资价值资产和品牌资产或同时投资关系资产和品牌资产反而会使顾客忠诚意向降低.研究结论能够为银行管理者优化营销经费配置提供理论支持.     

带负顾客的Geom/Geom/1单重休假排队(英文)

本文研究了正负顾客到达均服从几何分布,服务台在工作休假期以较低的服务速率运行的 Geom/Geom/1休假排队.运用嵌入马尔科夫链和矩阵分析法,得到了系统中等待队长和稳态队长的概率母函数,并从证明过程和结果中,分别得到了服务台在闲期、忙期、工作休假期、正规忙期的概率.     

基于属性识别理论的知识型员工忠诚度评价

分析了知识型员工的特征,确定了评价知识型员工忠诚度的指标体系.并应用属性识别模型来评价知识型员工忠诚度的等级.在确定二级评价指标的属性权重时,采用熵值法这一客观性方法来确定.通过实例,将这种方法应用于具体的评价,为评价知识型员工忠诚度提供了一种量化处理的方法.     

具有不耐烦顾客和多重工作休假的排队库存系统

研究具有不耐烦顾客和多重工作休假的M/M/1/N排队库存系统模型,分别考虑了系统中库存为零时服务员休假和系统中顾客数为零时服务员休假两种休假方式,基于(s,S)库存策略,运用矩阵迭代方法得到了系统稳态概率分布,并给出系统相关性能指标,进而建立系统平均库存费用函数.通过数值算例对比分析了两种休假方式下的系统主要参数变化对...