Abstract
In this article, we introduce a nonparametric (or distribution-free) estimator for traffic intensity in multi-server queues, which has not yet been discussed in the literature. Because this is a very useful model with many potential practical applications, it is the main focus of this study. We compare the performance of a new nonparametric estimator for situations in which the use of Markovian multi-server queues (M/M/s queues in Kendall notation) is adequate or in which it is necessary to consider multi-server queues with general arrival and general service times. We show that, when the parametric Markovian assumptions of M/M/s queues are satisfied, the new estimator is not superior to the maximum likelihood estimator based on the Markovian assumption with respect to M/M/s queues. However, for situations in which the interarrival time distribution and/or the service time distribution cannot be considered exponential (that is, non-Markovian), the new nonparametric estimator is superior. All evaluations are carried out using Monte Carlo simulations. A detailed numerical example is presented to show the usefulness of the technique for practical applications.
Similar content being viewed by others
Availability of data and material
The data used to support the findings of this study are included within the article.
Code Availability
The proposed algorithms can be encoded in the reader’s favorite programming language. R scripts are included.
References
Acharya, S.K. and Singh, S.K. (2019). Asymptotic properties of maximum likelihood estimators from single server queues: A martingale approach. Communications in Statistics - Theory & Methods, 48(14):3549–3557.
Acharya, S.K., Singh, S.K., and Villarreal-Rodríguez, C.E. (2020). Asymptotic study on change point problem for waiting time data in a single server queue. International Journal of Management Science and Engineering Management, 15(1):39–46.
Almehdawe, E., Jewkes, B., and He, Q.-M. (2013). A Markovian queueing model for ambulance offload delays. European Journal of Operational Research, 226(3):602–614.
Almeida, M.A.C. and Cruz, F.R.B. (2018). A note on Bayesian estimation of traffic intensity in single-server Markovian queues. Communications in Statistics - Simulation & Computation, 47(9):2577–2586.
Almeida, M.A.C., Cruz, F.R.B., Oliveira, F.L.P., and de Souza, G. (2020). Bias correction for estimation of performance measures of a Markovian queue.Operational Research, 20(2):943–958.
Armero, C. and Bayarri, M.J. (1994a). Bayesian prediction in \(M/M/1\) queues. Queueing System, 15:401–417.
Armero, C. and Bayarri, M.J. (1994b). Prior assessments for prediction in queues. Journal of the Royal Statistical Society. Series D (The Statistician), 43(1):139–153.
Armero, C. and Bayarri, M.J. (1996). Bayesian questions and answers in queues. In Bernardo, J. M., Berger, J. O., Dawid, A. P., and Smith, A. F. M., editors, Bayesian Statistics, pages 3–23. Oxford University Press, Oxford.
Armero, C. and Bayarri, M.J. (1997). A Bayesian analysis of a queueing system with unlimited service. Journal of Statistical Planning and Inference, 58(2):241–261.
Armero, C. and Bayarri, M.J. (1999). Dealing with uncertainties in queues and networks of queues: A Bayesian approach. In Multivariate analysis, design of experiments and survey sampling, (S. Ghosh, ed.). pages 579–608. Springer Science+Business Media, Marcel Dekker, New York, NY.
Armero, C. and Bayarri, M. J. (2001). Queues. In International Encyclopedia of the Social & Behavioral Sciences, (N.J. Smelser, and P.B. Baltes, eds.). pages 12676–12680. Pergamon, Oxford.
Armero, C. and Conesa, D. (1998). Inference and prediction in bulk arrival queues and queues with service in stages. Applied Stochastic Models and Data Analysis, 14(1):35–46.
Armero, C. and Conesa, D. (2000). Prediction in Markovian bulk arrival queues. Queueing Systems, 34(1):327–350.
Armero, C. and Conesa, D. (2004). Statistical performance of a multiclass bulk production queueing system. European Journal of Operational Research, 158(3):649–661.
Armero, C. and Conesa, D. (2006). Bayesian hierarchical models in manufacturing bulk service queues. Journal of Statistical Planning and Inference, 136(2):335–354.
Banerjee, A., Gupta, U.C., and Goswami, V. (2014). Analysis of finite-buffer discrete-time batch-service queue with batch-size-dependent service. Computers & Industrial Engineering, 75:121–128.
Basak, A. and Choudhury, A. (2021). Bayesian inference and prediction in single server \(M/M/1\) queuing model based on queue length. Communications in Statistics - Simulation & Computation, 50(6):1576–1588.
Basawa, I.V., Bhat, U.N., and Lund, R. (1996). Maximum likelihood estimation for single server queues from waiting time data. Queueing Systems, 24(1):155–167.
Basawa, I.V. and Prabhu, N.U. (1988). Large sample inference from single server queues. Queueing Systems, 3:289–304.
Beneš, V.E. (1957). A sufficient set of statistics for a simple telephone exchange model. The Bell System Technical Journal, 36(4):939–964.
Bhat, U.N. (2015). An introduction to queueing theory: Modeling and analysis in applications. Birkhäuser Basel, Boston, MA, second edition.
Chandrasekhar, P., Vaidyanathan, V.S., Durairajan, T.M., and Yadavalli, V.S.S. (2021). Classical and Bayes estimation in the \(M/D/1\) queueing system. Communications in Statistics - Theory and Methods, 50(22):5411–5421.
Chemweno, P., Brackenier, L., Thijs, V., Pintelon, L., van Horenbeek, A., and Michiels, D. (2016). Optimising the complete care pathway for cerebrovascular accident patients.Computers & Industrial Engineering, 93:236–251.
Choudhury, A. and Borthakur, A.C. (2008). Bayesian inference and prediction in the single server Markovian queue. Metrika, 67(3):371–383.
Chowdhury, S. and Mukherjee, S.P. (2013). Estimation of traffic intensity based on queue length in a single \(M/M/1\) queue. Communications in Statistics - Theory & Methods, 42(13):2376–2390.
Clarke, A.B. (1957). Maximum likelihood estimates in a simple queue.The Annals of Mathematical Statistics, 28(4):1036–1040.
Cochran, J.K. and Broyles, J.R. (2010). Developing nonlinear queuing regressions to increase emergency department patient safety: Approximating reneging with balking.Computers & Industrial Engineering, 59(3):378–386.
Cruz, F.R.B., Almeida, M.A.C., D’Angelo, M.F.S.V., and van Woensel, T. (2018). Traffic intensity estimation in finite Markovian queueing systems. Mathematical Problems in Engineering, 2018(Article ID 3018758):15.
Cruz, F.R.B., Quinino, R.C., and Ho, L.L. (2017). Bayesian estimation of traffic intensity based on queue length in a multi-server \(M/M/s\) queue. Communications in Statistics - Simulation & Computation, 46(9):7319–7331.
Cruz, F.R.B., Santos, M.A.C., Oliveira, F.L.P., and Quinino, R.C. (2021). Estimation in a general bulk-arrival Markovian multi-server finite queue. Operational Research, 21(1):73–89.
Ebert, A., Wu, P., Mengersen, K., and Ruggeri, F. (2020). Computationally efficient simulation of queues: The R package queuecomputer. Journal of Statistical Software, 95(5):1–29.
Govil, M.K. and Fu, M.C. (1999). Queueing theory in manufacturing: A survey. Journal of Manufacturing Systems, 18(3):214–240.
Gross, D., Shortle, J.F., Thompson, J.M., and Harris, C.M. (2009). Fundamentals of queueing theory. Wiley-Interscience, New York, NY, forth edition.
Johns Hopkins University & Medicine (2022). Coronavirus resource center. https://coronavirus.jhu.edu/. Accessed 5 April 2022.
Koole, G. and Mandelbaum, A. (2002). Queueing models of call centers: An introduction. Annals of Operations Research, 113(1-4):41–59.
Lakatos, L., Szeidl, L., and Telek, M. (2013). Introduction to queueing systems with telecommunication applications. Springer Science & Business Media, New York, NY.
Mcgrath, M.F., Gross, D., and Singpurwalla, N.D. (1987). A subjective Bayesian approach to the theory of queues I - Modeling. Queueing Systems, 1(4):317–333.
McGrath, M.F. and Singpurwalla, N.D. (1987). A subjective Bayesian approach to the theory of queues II - Inference and information in \(M/M/1\) queues. Queueing Systems, 1(4):335–353.
Papadopolous, H.T., Heavey, C., and Browne, J. (1993). Queueing theory in manufacturing systems analysis and design. Springer Science & Business Media.
Press, W.H., Teukolsky, S.A., Vetterling, W.T., and Flannery, B.P. (2007). Numerical recipes: The art of scientific computing. Cambridge University Press, New York, NY, third edition.
Quinino, R.C. and Cruz, F.R.B. (2017). Bayesian sample sizes in an \(M/M/1\) queueing system. The International Journal of Advanced Manufacturing Technology, 88(1):995–1002.
R Core Team (2023). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/.
Ross, J.V., Taimre, T., and Pollett, P.K. (2007). Estimation for queues from queue length data. Queueing Systems, 55(2):131–138.
Ross, S.M. (1996). Stochastic processes. John Wiley & Sons, Inc., New York, NY, second edition.
Schruben, L. and Kulkarni, R. (1982). Some consequences of estimating parameters for the \(M/M/1\) queue. Operations Research Letters, 1(2):75–78.
Selvaraju, N. and Goswami, C. (2013). Impatient customers in an \(M/M/1\) queue with single and multiple working vacations. Computers & Industrial Engineering, 65(2):207–215.
Siegel, S. and Castellan Jr., N.J. (1988). Nonparametric statistics for the behavioral sciences. McGraw-Hill, New York, NY, second edition.
Singh, S.K. (2017). Bayesian change point problem for Erlang inter arrival time distribution. Journal of Statistics and Mathematical Engineering, 3(2–3):1–8.
Singh, S.K. and Acharya, S.K. (2019a). Bayesian change point problem for traffic intensity in \(M/E_r/1\) queueing model. Japanese Journal of Statistics and Data Science, 2(1):49–70.
Singh, S.K. and Acharya, S.K. (2019b). Equivalence between Bayes and the maximum likelihood estimator in \(M/M/1\) queue. Communications in Statistics - Theory and Methods, 48(19):4780–4793.
Singh, S.K. and Acharya, S.K. (2021). Bernstein-von Mises theorem and Bayes estimation from single server queues. Communications in Statistics - Theory and Methods, 50(2):286–296.
Singh, S.K., Acharya, S.K., Cruz, F.R.B., and Quinino, R.C. (2021a). Bayesian sample size determination in a single-server deterministic queueing system.Mathematics and Computers in Simulation, 187:17–29.
Singh, S.K., Acharya, S.K., Cruz, F.R.B., and Quinino, R.C. (2021b). Estimation of traffic intensity from queue length data in a deterministic single server queueing system. Journal of Computational and Applied Mathematics, 398:113693.
Singh, S. K., Acharya, S. K., Cruz, F. R. B., and Cançado, A. L. F. (2023a). Change point estimation in an \(M/M/2\) queue with heterogeneous servers. Mathematics and Computers in Simulation, 212:182–194.
Singh, S.K., Acharya, S.K., Cruz, F.R.B., and Quinino, R.C. (2023b). Bayesian inference and prediction in an \(M/D/1\) queueing system. Communications in Statistics - Theory and Methods, 52(24):8844–8864.
Singh, S.K., Cruz, F.R.B., Gomes, E.S., and Banik, A.D. (2023c). Classical and Bayesian estimations of performance measures in a single server Markovian queueing system based on arrivals during service times. Communications in Statistics - Theory and Methods (in press), 1–30. https://doi.org/10.1080/03610926.2022.2155789.
Suyama, E., Quinino, R.C., and Cruz, F.R.B. (2018). Simple and yet efficient estimators for Markovian multi-server queues. Mathematical Problems in Engineering, 2018(Article ID 3280846):7.
Zheng, S. and Seila, A.F. (2000). Some well-behaved estimators for the \(M/M/1\) queue. Operations Research Letters, 26(5):231–235.
Acknowledgements
We would like to thank the Editor-in-Chief and the two referees for their detailed and insightful comments, which led to a much-improved manuscript.
Funding
VBQ and FRBC acknowledges CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, grants 160974/2020-8, 148989/2021-7, and 305442/2022-8) and FAPEMIG (Fundação de Amparo à Pesquisa do Estado de Minas Gerais, grant CEX-PPM-00564-17), for partial financial support.
Author information
Authors and Affiliations
Contributions
All authors, VBQ, FRBC, and RCQ contributed equally to the design and implementation of the research, to the analysis of the results, and to the final writing of the manuscript.
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Appendix A Script in R
Appendix A Script in R
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Quinino, V.B., Cruz, F.R.B. & Quinino, R.C. Nonparametric Estimation for Multi-server Queues Based on the Number of Clients in the System. Sankhya A 86, 494–529 (2024). https://doi.org/10.1007/s13171-023-00331-9
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13171-023-00331-9
Keywords
- Multi-server queues
- Markovian queues
- General queues
- Traffic intensity
- Maximum likelihood estimators
- Nonparametric estimator
- Bootstrap