Two‐tier healthcare service systems and cost of waiting for patients

Waiting has been a significant concern for healthcare services. We address this issue in the context of a two‐tier service system in this study. A two‐tier healthcare service system consists of two different service providers, typically one public service provider and one private service provider. In a baseline model, the two service providers are modeled by two queue servers, which charge each patient a common fixed fee for the service. Then, we study a queue model in which one service provider offers a subsidy or charges a premium while the other maintains the fixed service fee. This system provides a mechanism to segment patients along their waiting time cost through price discrimination. We analyze the problem from both the perspective of minimizing total waiting cost for all patients and the perspective of maximizing social gain for the public service provider or profit for the private service provider. We show that this model can significantly alleviate the burden of waiting for patients. The study addresses the design, the efficiency, and the implementation of two‐tier healthcare service systems. Copyright © 2017 John Wiley & Sons, Ltd.     

A single server queue with cyclically indexed arrival and service rates

In this paper we consider a queueing model that results from at least two apparently unrelated areas. One motivation to study a system of this type results from a test case of a computer simulation factor screening technique calledfrequency domain methodology. A second motivation comes from manufacturing, where due to cyclic scheduling of upstream machines, the arrival process to downstream machines is periodic. The model is a single server queue with FIFO service discipline and exponential interarrival and service times where the arrival and/or service rates are deterministic cyclic functions of the customer sequence number. We provide steady state results for the mean number in the system for the model with cyclic arrival and fixed service rates and for the model with fixed arrival and cyclic service rates. For the model with both cyclic arrival and service rates, upper and lower bounds are developed for the steady state mean waiting time in the system. Throughout the paper various implications and/or insights derived from the results of this study are discussed for frequency domain methodology.The authors acknowledge the financial support of the CBA/GSB Faculty Research Committee of the College of Business Administration, The University of Texas at Austin.     

Cascades of queues

This paper presents results from a bulk service queueing system, where the main service takes place at fixed time intervals, but where back-up (or relief) services may be introduced in times of heavy demand on the system. On occasions the back-up service itself may receive further back-up services, thus leading to the concept of a cascade of queues flowing from the original main service. Analytic expressions are derived for the mean queue lengths at the points of delivery of service, and the computational requirements are discussed in detail. Sample numerical results and a simple cost analysis are provided.     

Scheduling arrivals to a stochastic service mechanism

We consider the problem of scheduling the arrivals of a fixed number of customers to a stochastic service mechanism to minimize an expected cost associated with operating the system. We consider the special case of exponentially distributed service times and the problems in general associated with obtaining exact analytic solutions. For general service time distributions we obtain approximate numerical solutions using a stochastic version of gradient search employing Infinitesimal Perturbation Analysis estimates of the objective function gradient obtained via simulation.     

Invariance of stationary probabilities of states for network of multiserver queues

A queueing network consisting of multiserver nodes with different sources of customers is considered. We investigate stationary probability distributions of network states. Their invariance with respect to the functional form of distributions of input and service processes is established under fixed expectations of these distributions and service discipline when any entering customer has a preemptive resume discipline.     

Balancing admission control,speedup, and waiting in service systems

Queueing Systems - Consider a population of customers, each of which needs to decide independently when to arrive to a facility that provides a service during a fixed period of time, say a day....     

Workforce cross-training decisions in field service systems with two job types

When job types are heterogeneous in a multi-server service system, pooling servers to reduce system delay requires cross-training. Managers should balance a reduction in customer waiting time with high service costs and possibly reduced server efficiency due to cross-training. In a field service system with two job types and a fixed number of servers, the determination of the mix of dedicated and cross-trained servers is a critical managerial decision. We were motivated by a real field service situation to study a model where the objective is to minimize the sum of the average service costs and the customer delay costs per unit time. We use simulation to investigate the impact of various system parameters such as the number of servers, server utilization, and server efficiency on the optimal workforce mix.     

社会互动视角下的服务型企业最优运营策略研究

本文主要研究在社会互动的影响下,服务型企业如何制定以价格、服务速率为代表的运营管理策略,从而实现利润最大化。首先,基于M/M/1排队模型对顾客购买决策过程进行建模分析,考虑单个服务型企业在实现利润最大化的目标条件下,社会互动的作用如何影响定价和服务速率决策;其次,研究在竞争市场环境中,社会互动如何影响市场均衡状态下各企业的运营决策和市场份额。结果表明,无论在垄断还是竞争的市场环境中,社会互动对服务型企业的最优运营决策均有不同程度与方向的影响。     

客源充足情境下的customer-intensive服务策略研究

在customer-intensive服务中服务速度越慢,顾客的效用就越高,然而等待时间也随之变长;而服务商则需对服务速度和价格进行决策,以求获得最优收益。本文基于客源丰富的服务垄断商对此问题采用M/M/1排队模型进行了研究,将顾客成本细分为时间成本和焦虑成本,给出了最优服务速度和价格。研究发现,单位焦虑成本的增加造成了服务商收益的减少,但对收益的影响要小于单位时间成本。最后,提出了服务商投入一定的服务成本来减少焦虑成本的策略,以达到获取更高收益的目的,并证明了策略的有效性。     

The BMAP/SM/1 retrial queue with controllable operation modes

We deal with a single-server retrial queueing system having two modes of operation. Under the fixed mode, the system operates as an usual system with a batch Markovian arrival process (BMAP), semi-Markovian (SM) service process and a constant total retrial rate. Different modes are distinguished by characteristics of the input, service and retrial rate. The mode of operation can be switched at the service completion epochs depending on the queue-length. The strategy of control belongs to the class of hysteretic strategies. We calculate a stationary distribution of numbers of calls in the orbit at service completion epochs. We also discuss the problem of optimizing the strategy of control.     

A model of JIT make-to-stock inventory with stochastic demand

We consider a firm that manages its internal manufacturing operations according to a just-in-time (JIT) system but maintains an inventory of finished goods as a buffer against random demands from external customers. We formulate a model in which finished goods are replenished by a small fixed quantity each time period. In the interest of schedule stability, the size of the replenishment quantity must remain fixed for a predetermined interval of time periods. We analyse the single-interval problem in depth, showing how to compute a cost-minimising value of the replenishment quantity for a given interval length, and characterising the optimal cost, inventory levels and service as functions of the interval length and initial inventory. The model displays significant cost and service penalties for schedule stability. A dynamic version of the problem is also formulated, and shown to be convex in nature with relatively easily computed optima.     

Heuristic procedures for a stochastic batch service problem

This paper considers a multi-class batch service problem that involves a class-dependent waiting cost and a service cost in determining customer batch sizes. Unlike a fixed service cost used widely in standard models, the service cost considered in this work is incurred only if the total service time is over the capacity. We formulate this problem as an infinite horizon Markov decision process, and exploit its structural properties to establish theoretical results, including bounds on the optimal action space. We use the results to improve the value iteration procedure. Furthermore, we design heuristic algorithms for large problems. The numerical experiments demonstrate that the class-dependent waiting cost has a considerable influence on the optimal customer batch size. Finally, we evaluate the efficiency of the proposed value iteration procedure and the quality of the heuristic solutions.     

服务率可变的批服务排队网络

大部分排队网络的研究结果是在服务率不变的条件下给出的。本文分析了两类成批服务的排队网络。并在服务率依赖于批服务大小的条件下，利用各节点的准可逆性，给出了不带信号和带消极信号的两类排队网络的乘积形式稳态解．并利用不动点原理，证明了交通方程解的存在性．并给出求法。     

考虑消费者忠诚的雇员激励契约设计

在信息不对称条件下,企业雇主如何在员工行为无法被观测到的情况下达到最优绩效成为企业上层需要解决的重要问题。在此背景下,区别于既有文献,本文根据服务型企业以消费者为中心的特点,将消费者忠实度纳入委托——代理模型,通过设计企业激励契约机制,探讨了企业雇佣员工的最佳方式。结果表明:(1)长期稳定工作的员工会选择提成工资制,这类员工倾向于将努力水平用于提高消费者忠诚度,其选择的结果能为企业带来利润;(2)短期非稳定工作的员工选择固定工资制,这类员工的零付出将给企业造成亏损,且损失额即为短期非稳定员工的固定工资额;(3)选择提成工资制的员工将给服务型企业带来正效益,而选择固定工资制的员工给企业带来固定工资的损失额。本文从企业雇佣员工方式的角度,为企业更偏向于为直接面对消费者创造业绩的服务型员工采取提成工资制,而为没有直接面对消费者的非服务型员工采用固定工资制提供了一种解释,有助于把握企业管理的着力点,进而增强企业绩效提升对经济发展的推动性作用。     

A semi-preemptive priority scheduling discipline: Performance analysis

In this paper, we present an in-depth analytical study of a semi-preemptive priority scheduling discipline. This discipline eliminates the deficits of both the full- and non-preemptive versions. Under the non-preemptive category, in particular, higher-priority customers may have to wait even when the service of a lower-priority customer has just started, while under the full-preemptive discipline, the almost completed service of a lower-priority customer may be interrupted due to the arrival of higher-priority customers, possibly causing a large extra delay. For fixed low-priority service times, the semi-preemptive priority scheduling discipline shows a performance gain of up to 6% compared to the full- and non-preemptive versions.     

Price and QoS competition in data communication services

Pricing of data communication services has been studied, but primarily in a monopolistic setting. We study the price competition in packet-switching networks with a quality-of-service (QoS) guarantee in terms of an expected per-packet delay. We propose a general framework in which service providers offering multi-class priority-based services compete to maximize their profits, while satisfying the expected delay guarantee in each class. We first examine the price competition with fixed delay guarantees and then extend it to the situation where providers compete in quality of service as well as price. In each case, we compare the duopoly pricing scheme with the case when two service providers merge to become a monopoly provider.     

Who should be given priority in a queue?

We consider a memoryless single server queue with two classes of customers, each having its fixed entry fee. We show that profit and social welfare may benefit from a service discipline based on relative priorities.     

An M/G/1-type queuing model with service times depending on queue length

A study is made of an M/G/1-type queuing model in which customers receive one type of service until such time as, at the end of a service, the queue size is found to exceed a given value N, N ≥ 1. Then a second type of service is put into effect and remains in use until the queue size is reduced to a fixed value K, 0 ≤ K ≤ N. Equations are derived for the stationary probabilities both at departure times and at general times. An algorithm is developed that allows the rapid computation of the mean queue length and some important probabilities.     

Service outsourcing under co-opetition and information asymmetry

Co-opetition refers to the phenomenon that firms simultaneously cooperate and compete in order to maximize their profits. This paper studies the contracting for an outsourcing supply chain (a user company vs. a service provider) in the presence of co-opetition and information asymmetry. The user company outsources part of his service capacity at a discount price to the service provider for sale. The service provider charges a commission for doing outsourcing work and competes with the user company for the service capacity to satisfy their respective demands. We solve for the service provider’s optimal commission decision and the user company’s optimal outsourcing decisions (outsourcing volume and price discount) when the user company has private information about his service capacity. Specifically, we highlight the following observations. For the service provider, a menu of two-part tariffs that consist of a fixed commission and a per-volume commission can reveal the true type of the user company’s capacity; the user company’s optimal outsourcing proportion is quasi-convex and the optimal price discount is non-decreasing in his capacity volume, which is counterintuitive.