A Path Construction for the Virtual Waiting Time of an M/G/1 Queue

Consider the M/G/1 queue, the finite dam M/G/1 with capacity T, and the impatient customer M/G/1 model, where customers become lost customers if their waiting time exceeds τ. In this note we prove that for all three models and each xe(0, r) the distribution of the number of downcrossings of the virtual waiting time process with level x during a busy cycle is identical. This implies the weaker statement that on [0, T) the distribution functions of the steady state distributions of the amount of unprocessed work (virtual waiting time) are proportional. A number of applications is given.     

THE JOINT ARRIVAL AND DEPARTURE PROCESS FOR THE M/M/l QUEUE

We consider the M/M/1-queue and derive an explicit expression for the joint distribution of the number of arrivals and the number of departures in [0, t), given the number of customers initially present. The derivation is almost purely combinatorial, it avoids the use of generating functions, and immediately yields a simple probabilistic interpretation of the result.     

带后续队列长度通告的呼叫中心性能分析

从排队心理学的角度考虑了队列长度对顾客等待耐心的影响,设计了一个带队列信息通告机制的M／M／N模型。等待的顾客可以像有形排队一样获知目前排队的人数及其所处的队列位置,并以此决定继续等待或者放弃。使用仿真方法对该机制下的呼叫中心性能进行了分析,并与Erlang—A模型和Erlang—C模型进行了比较。     

The M/M/1 queue with gated random order of service

We analyse an M / M /1 queueing model with gated random order of service discipline. In this service discipline there is a waiting room, in which arriving customers are collected, and a service queue. Each time the service queue becomes empty, all customers in the waiting room are instantaneously put in random order in the service queue. We find the joint stationary distribution of the number of customers in the waiting room and the service queue. Furthermore, we obtain the bivariate Laplace–Stieltjes transform of the joint distribution of the sojourn times of a customer in the waiting room and the service queue.     

基于XML/EDI的电子商务物流浅析

随着XML的迅速发展,XML正在逐步成为Internet中描述数据的标准,其将在电子商务物流领域得到有效应用。通过描述传统EDI物流系统存在的局限性,并分析XML技术应用于EDI的优势所在,提出了基于XML/EDI电子商务物流系统结构模型,使得电子商务物流在Internet上不同系统之间信息交换更加便捷,而且大大降低了成本并提高了安全性。     

On a bivariate Markov process arising in the theory of single-server retrial queues

We introduce a bivariate Markov process which can be seen as the joint process of the channel state and the number of customers in orbit of a Markovian single-server retrial queue with state dependent intensities. We obtain a necessary and sufficient condition for the process to be regular, and necessary and sufficient conditions for ergodicity and recurrence. A product-form formula for the stationary distribution is obtained. Besides, we study the busy period, the number of served customers and other related quantities. We show that for all the above problems there exist "equivalent" birth-and-death processes. However, a "uniformly equivalent" birth-and-death process does not exist.     

Balking and reneging in M/G/1 systems with post-ponable interruptions

Summary This paper considers the effect of postponable interruptions on aM/G/1 queueing process where customers balk with probabilityn/N (n=0, 1, 2, …,N) and renege after having waited for a random length of time. The busy period process in which transitions from any state (m, n) to any other state are permitted without an intermediate passage to the empty state, is investigated employing the supplementary variable method and discrete transforms. Later, the general process in which busy periods alternate with idle periods has been discussed in terms of the busy period process and renewal distributions and finally the ergodic properties of the general process studied by appealing to some results of renewal theory.     

自动化立体仓库系统可靠性研究

介绍了系统可靠性基本概念，分析了自动化立体仓库系统组成与工作流程，以有轨小车输送货物出入库工作流程为例，建立了系统可靠性计算模型，并探讨了提高系统可靠性的方法与措施。     

基于CAXA环境下电风扇叶片CAD/CAPP/CAM技术研究

本文以国产主流软件CAXA作为CAD/CAPP/CAM的软件环境,以复杂的曲面—塑料电风扇叶片为例,对叶片进行设计,注塑模的模具生成,模具的加工工艺设计,模具的加工仿真等工艺过程分析,对复杂曲面的CAD/CAPP/CAM数字化快速化制造技术提供了依据。     

Optimization tools for design and marketing of new/improved products using the house of quality

Quality function deployment (QFD) has helped many firms realize significant reduction in product design costs and development time. The QFD process includes ranking customer preferences, rating the competitors, and parts deployment for the new/improved product. Prior to this research, such activities have been performed based on expert opinion, or the “best-in-class” approach. We develop and solve optimization models for the identification of consensus rankings and ratings, that take into account the priorities and perceptions of all the customers in a target market. Then, based on the consensus rankings, we identify a parts mix for the new/improved product that satisfies a budget constraint and matches or exceeds the performance expectations of all customers surveyed in the target market. Finally, we show how the QFD charts can be used to identify competitors that are falsely perceived as superior, as well as areas where the firm's marketing strategies have had the desired effects. Such insights are useful in developing the future marketing strategy of the firm.     

基于企业内部供应链的订单流程优化研究

随着经济增长和科技发展,电子产品成为日益增长的消费品,且客户的个性化需求快速发展,使得当今的电子产品制造型企业,为适应激烈市场竞争环境的要求,分解竞争压力,开始将生产经营纷纷转向以顾客订单为导向的按单生产模式,以降低经营风险。在这种生产经营模式下,如何优化订单流程,及时、高效满足客户需求,提高客户忠诚度,成为制造型企业亟待解决的问题。由于订单流是内部供应链的媒介,基于内部供应链进行订单流程优化能够满足企业的需求,通过描述订单流程图,分析现有订单流程中存在的问题,并建立了新的可行性流程。     

Waiting time probabilities in the M/G/1 + M queue

We consider an M/G/1 queueing system where the customers may leave the queue if their services do not commence before an exponentially distributed random time. The (conditional) offered waiting time distribution is approximated by a gamma distribution via matching the first and second moments of the actual waiting time. A simulation study is conducted to assess the accuracy of the approximation and it reveals that the approximation performs satisfactorily under general conditions on service time distributions.     

Creating space for play/invention – concepts of space and organizational entrepreneurship

This paper focuses on how one can relate management thinking/practices to entrepreneurial processes in the context of formal organization. In order to do this we develop a number of related ‘spatial concepts’ providing us with the possibility of describing entrepreneurship as a ‘creation and use of space for play/innovation’. Using concepts of space, the managerial and the entrepreneurial dimensions and perspectives on organizing creativity become highly visible in the case studied. This is a field study (within the ethnographic tradition) focusing on an organizational transformation of a former public authority into a competitive limited company. A distinction between managerialism and ‘entrepreneurship as event’ is proposed as conceptually fruitful as well as useful for discussing recommendations to managers for how to handle entrepreneurial processes. A minimal and contextual role for management is suggested when aspiring to support the creations of space for play/invention, for example, for entrepreneurship as forms of organizational creativity.     

城市食品冷链物流B2B/B2C融合共配流程再造研究

随着电子商务的进一步发展,生鲜电商发展迅猛,城市食品冷链物流迎来高速发展。冷链物流B2C配送业务具有种类多、时效性强、客户分散、单位数量少等特点,导致单位配送成本居高不下,严重影响了冷链配送的效率。文章在对国内外研究成果进行总结概括后,分别对冷链物流、共同配送、流程再造三部分进行分析。运用Petri网对B2B/B2C融合共配前后进行建模,采用关联矩阵分析法验证再造前后模型的准确性。借助Arena软件对配送过程进行仿真,通过对比分析再造前后的总时间、成本、效率、车辆满载率等仿真数据的变化,模拟实际配送情况,验证文章中流程再造的科学性。     

Green indoor and outdoor environment as nature‐based solution and its role in increasing customer/employee mental health,well‐being,and loyalty

The present study was an empirical endeavor to explore the effect of nature‐based solutions (NBS) on the customer and employee loyalty generation process by considering the role of mental health and well‐being in the hotel industry. A quantitative approach was employed. A survey methodology with a convenience sampling technique was used to collect the data. A total of 303 responses and 301 responses for customer and employee groups, respectively, were used for data analysis. Our results of the structural analysis indicated that green indoor and outdoor environment as NBS helps customers and employees improve mental health perception, emotional well‐being, and loyalty. In addition, the prominent role of emotional well‐being in building customer loyalty and of mental health perception in building employee loyalty was uncovered. The developed conceptual frameworks for customers and employees contained a satisfactory ability in predicting loyalty. Mental health perception and emotional well‐being were mediators. Moreover, the relationship strength among study variables differed between customer and employee groups. Overall, our findings significantly increased our understanding of NBS and its critical role in the hotel industry.     

The M/G/∞ Queueing Model for Optimistic Concurrency Control

The M / G /∞ queue with Optimistic Concurrency Control (OCC) is a model for a special form of parallel transaction processing in a real-time database. Transactions arrive according to a Poisson process and require some generally distributed execution time. One of the differences with ordinary multi- and infinite-server queueing models is that under OCC the successful completion of one transaction may immediately cause the failure of one or more of the other transactions. This happens if the completing transaction has overwritten a data-item that is in use by another transaction in progress. As soon as this failure is detected the failed transaction is restarted. So the total service time of a transaction consists of its final successful run and the time spent on unsuccessful runs.
In this study we develop an approximation for the distribution of the total service time, and test the approximation against simulation. Although in practice the number of servers is never unlimited, this study provides valuable insight in the asymptotics with respect to the number of servers. The approximation clearly demonstrates the very limited performance gain from an increase of the number of servers.     

顾客声音数据处理一致化映射关系研究

在顾客声音数据一致化处理过程中,原始客户需求信息容易丢失是企业营销决策难题。文中尝试用图形化形式描述顾客声音数据一致化转化过程,给出了一种面向群决策的三类不同顾客声音(效用值型的顾客声音、次序值型的顾客声音、语言短语型的顾客声音)的一致化映射方法。该方法是一种考虑企业知识背景等相关要素的非强制性数据转换方法,能最大限度地保证数据在转换的过程中不丢失,对支持企业营销决策具有重要理论意义及实用价值。     

电信客户信用评价实证分析

文章主要立足于客户长期价值提升的思想,基于定性和定量结合的层次分析法建立电信企业的客户信用评价指标体系,重点分析了个人用户的信用评价指标体系的建立过程,最后给出了数据实证分析。     

Bagging方法在基于日常交易数据解决中小企业的信用评价问题中的应用

关于信用风险评价问题至今已经做了很多研究,各种信用评价模型与方法也已被开发。但是这些模型与方法几乎都是基于财务数据、股票价格或风险调研机构发表的各种调查结果。因为几乎所有的中小企业的财务数据都是非公开的,至今开发的信用评价模型与方法都不免成为无米之炊。为此,本文提出了一个新的途径,只需要根据销售额、顾客付款额、拖欠款额等日常业务处理数据来评价顾客企业的信用度。本文提出一个应用Sagging方法评价顾客信用的系统,其目的在于解决由于异常顾客数比正常顾客要少很多而带来的问题,提高分辨异常顾客的能力。本文所提出的信用评价系统将应用到一个实际企业的信用评价问题中,借此来验证系统的性能和效果。     

基于LabWindows/CVI的轧机振动测试系统应用研究

构建了基于LabWindows/CVI的轧机振动测试系统,轧机的振动测量使用加速度传感器,数据采集采用USB-6210数据采集卡,使用LabWindows/CVI语言编程,实现了对轧机振动信号进行数据采集、处理,此测试方法减少了复杂的硬件电路,简化了测控系统,提高了系统的测量精度和可靠性,可根据需要拓展测试系统的其它功能。