Optimal service rates of a service facility with perishable inventory items

2002 ◽  
Vol 49 (5) ◽  
pp. 464-482 ◽  
Author(s):  
O. Berman ◽  
K.P. Sapna
Keyword(s):  
Service Facility ◽  
Perishable Inventory ◽  
Optimal Service ◽  
Service Rates

scholarly journals Comparative analysis of models and performance indicators for optimal service facility location

2021 ◽  
Vol 145 ◽  
pp. 102174
Author(s):  
Edoardo Fadda ◽  
Daniele Manerba ◽  
Gianpiero Cabodi ◽  
Paolo Enrico Camurati ◽  
Roberto Tadei
Keyword(s):  
Comparative Analysis ◽  
Facility Location ◽  
Performance Indicators ◽  
Service Facility ◽  
Optimal Service ◽  
And Performance

OPTIMAL CONTROL POLICIES FOR AN M/M/1 QUEUE WITH A REMOVABLE SERVER AND DYNAMIC SERVICE RATES

2019 ◽  
pp. 1-21
Author(s):  
Pamela Badian-Pessot ◽  
Mark E. Lewis ◽  
Douglas G. Down
Keyword(s):  
Optimal Control ◽  
Rate Control ◽  
Optimal Policy ◽  
Numerical Experiments ◽  
Service Rate ◽  
Warm Up ◽  
Cost Criterion ◽  
Optimal Service ◽  
Removable Server ◽  
Service Rates

AbstractWe consider an M/M/1 queue with a removable server that dynamically chooses its service rate from a set of finitely many rates. If the server is off, the system must warm up for a random, exponentially distributed amount of time, before it can begin processing jobs. We show under the average cost criterion, that work conserving policies are optimal. We then demonstrate the optimal policy can be characterized by a threshold for turning on the server and the optimal service rate increases monotonically with the number in system. Finally, we present some numerical experiments to provide insights into the practicality of having both a removable server and service rate control.

Optimal service rates in the multiserver loss system with heterogeneous servers

1981 ◽  
Vol 18 (03) ◽  
pp. 776-781 ◽  
Author(s):  
G. B. Nath ◽  
E. G. Enns
Keyword(s):  
Heterogeneous System ◽  
Percentage Reduction ◽  
Heterogeneous Servers ◽  
Loss System ◽  
Optimal Service ◽  
Service Rates

A multichannel loss system with heterogeneous servers operating in parallel is analyzed. The sum of the service rates of all servers is assumed constant. The optimal service rates that minimize the probability of losing a customer are obtained, and are shown to be different from each other. The percentage reduction in the probability of losing a customer in the homogeneous and the best heterogeneous system for a few representative values are included.

Optimal control of service rates in networks of queues

1987 ◽  
Vol 19 (1) ◽  
pp. 202-218 ◽  
Author(s):  
Richard R. Weber ◽  
Shaler Stidham
Keyword(s):  
Rate Control ◽  
Queueing Networks ◽  
Arrival Rate ◽  
Service Rate ◽  
Discounted Cost ◽  
Holding Costs ◽  
Optimal Service ◽  
Monotonicity Result ◽  
Service Rates ◽  
Number Of Customers

We prove a monotonicity result for the problem of optimal service rate control in certain queueing networks. Consider, as an illustrative example, a number of ·/M/1 queues which are arranged in a cycle with some number of customers moving around the cycle. A holding cost hi(xi) is charged for each unit of time that queue i contains xi customers, with hi being convex. As a function of the queue lengths the service rate at each queue i is to be chosen in the interval , where cost ci(μ) is charged for each unit of time that the service rate μis in effect at queue i. It is shown that the policy which minimizes the expected total discounted cost has a monotone structure: namely, that by moving one customer from queue i to the following queue, the optimal service rate in queue i is not increased and the optimal service rates elsewhere are not decreased. We prove a similar result for problems of optimal arrival rate and service rate control in general queueing networks. The results are extended to an average-cost measure, and an example is included to show that in general the assumption of convex holding costs may not be relaxed. A further example shows that the optimal policy may not be monotone unless the choice of possible service rates at each queue includes 0.

An approach by human and material resources combination to reduce hospitals crowding

2019 ◽  
Vol 15 (2) ◽  
pp. 58-79
Author(s):  
Sara Jebbor ◽  
Abdellatif El Afia ◽  
Raddouane Chiheb
Keyword(s):  
Human Resources ◽  
Optimal Number ◽  
Inpatient Unit ◽  
Service Rate ◽  
Hospital Inpatient ◽  
Queuing Networks ◽  
Content Type ◽  
Material Resources ◽  
Optimal Service ◽  
Service Rates

Purpose This paper aims to propose an approach by human and material resources combination to reduce hospitals crowding. Hospitals crowding is becoming a serious problem. Many research works present several methods and approaches to deal with this problem. However, to the best of the authors’ knowledge – after a deep reading of literature – in all the proposed approaches, human and material resources are studied separately while they must be combined (to a given number of material resources an optimal number of human resources must be assigned and vice versa) to reflect reality and provide better results. Design/methodology/approach Hospital inpatient unit is chosen as framework. This unit crowding reduction is carried out by its capacity increasing. Indeed, inpatient unit modeling is performed to find the adequate combinations of human and material resources numbers insuring this unit stability and providing optimal service rates. At first, inpatient unit is modeled using queuing networks and considering only two resources (beds and nurses). Then, the obtained service rate formula is improved by including other resources and parameters using Baskett, Chandy, Muntz and Palecios (BCMP) queuing networks. This work is applied to “Princess Lalla Meryem” hospital inpatient unit. Findings Results are patients’ average number reduction by an average (in each block) of three patients, patients’ average waiting time reduction by an average of 9.98 h and non-admitted patients (to inpatient wards) access percentage of 39.26 per cent on average. Originality/value Previous works focus their studies on either human resources or material resources. Only a few works study both resources types, but separately. The context of those studies does not meet the real hospital context (where human resources are combined with material resources). Therefore, the provided results are not very reliable. In this paper, an approach by human and material resources combination is proposed to increase inpatient unit care capacity. Indeed, this approach consists of developing inpatient unit service rate formula in terms of human and material resources numbers.

scholarly journals A Discrete-Time Queue with Balking, Reneging, and Working Vacations

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Veena Goswami
Keyword(s):  
Discrete Time ◽  
Cost Model ◽  
Single Server ◽  
Finite Buffer ◽  
Multiple Working Vacations ◽  
Optimal Service ◽  
Special Cases ◽  
Service Rates ◽  
Working Vacations ◽  
Vacation Period

This paper presents an analysis of balking and reneging in finite-buffer discrete-time single server queue with single and multiple working vacations. An arriving customer may balk with a probability or renege after joining according to a geometric distribution. The server works with different service rates rather than completely stopping the service during a vacation period. The service times during a busy period, vacation period, and vacation times are assumed to be geometrically distributed. We find the explicit expressions for the stationary state probabilities. Various system performance measures and a cost model to determine the optimal service rates are presented. Moreover, some queueing models presented in the literature are derived as special cases of our model. Finally, the influence of various parameters on the performance characteristics is shown numerically.

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