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On reinforcement-depletion compartmental urn models

Published online by Cambridge University Press:  14 July 2016

Peter Donnelly*
Affiliation:
Queen Mary College, University of London
Ward Whitt*
Affiliation:
AT&T Bell Laboratories
*
Postal address: School of Mathematical Sciences, Queen Mary College, University of London, Mile End Road, London El 4NS, UK.
∗∗Postal address: AT&T Bell Laboratories, Room 2C-178, Murray Hill, NJ 07974, USA.

Abstract

We verify and extend a conjecture of Purdue (1981) concerning the stochastic monotonicity of absorption times in a class of compartmental urn models. We also describe the effect of increased variability in the reinforcement sizes. Finally, we investigate variability in the content process for large populations. In many applications, compartmental models substantially under-represent the variability observed in the data, so that there has been considerable interest in modifying the model to increase the variability. We show that the squared coefficient of variation of the content is not asymptotically negligible when both the size and the variability of the reinforcements are of the same order as the initial population.

Type
Research Papers
Copyright
Copyright © Applied Probability Trust 1989 

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Footnotes

Partially supported by the U.S. National Science Foundation under Grant No. DMS-86–08857.

References

Ball, F. and Donnelly, P. (1989) A unified approach to variability in compartmental models. Biometrics. Google Scholar
Bernard, S. R. (1977) An urn model study of variability within a compartment. Bull. Math. Biol. 39, 463470.Google Scholar
Chung, K. L. (1974) A Course in Probability, 2nd edn. Academic Press, New York.Google Scholar
Kamae, T., Krengel, U. and O'Brien, G. L. (1977) Stochastic inequalities on partially ordered spaces. Ann. Prob. 5, 899912.Google Scholar
Leitnaker, M. G. and Purdue, P. (1985) Non-linear compartmental systems: extensions of S. R. Bernard's urn model. Bull. Math. Biol. 67, 193204.Google Scholar
Marshall, A. W. and Olkin, I. (1979) Inequalities: Theory of Majorization and Its Applications. Academic Press, New York.Google Scholar
Purdue, P. (1981) Variability in a single compartment system: a note on S. R. Bernard's model. Bull. Math. Biol. 43, 111116.Google Scholar
Ross, S. M. (1983) Stochastic Processes. Wiley, New York.Google Scholar
Shenton, L. R. (1981) A reinforcement-depletion urn problem–I. Basic theory. Bull. Math. Biol. 43, 327340.Google Scholar
Shenton, L. R. (1983) A reinforcement-depletion urn problem–II. Application and generalization. Bull. Math. Biol. 45, 19.Google Scholar
Sonderman, D. (1980) Comparing semi-Markov processes. Math. Operat. Res. 5, 110119.Google Scholar
Stoyan, D. (1983) Comparison Methods for Queues and Other Stochastic Models, ed. Daley, D. J. Wiley, New York.Google Scholar