Individual Growth in a Random Environment: An Optimization Problem
Abstract
We consider a class of stochastic differential equations model to describe individual growth in a random environment. Applying these models to the weight of mertolengo cattle, we compute the mean profit obtained from selling an animal to the meat market at different ages and, in particular, determine which is the optimal selling age. Using first passage time theory we can characterize the time taken for an animal to achieve a certain weight of market interest for the first time. In particular, expressions for the mean and standard deviation of these times are presented and applied to real data. These last results can be used to determine the optimal selling weight in terms of mean profit.
Keywords
Stochastic Differential Equation Random Environment Individual Growth Standard Normal Random Variable Drift CoefficientNotes
Acknowledgements
The first three authors are members of the Centro de Investigação em Matemática e Aplicações and the fourth author is member of the Instituto de Ciências Agrárias e Ambientais Mediterrânicas, both research centers of the Universidade de Évora financed by Fundação para a Ciência e Tecnologia (FCT). Braumann gratefully acknowledges the financial support from the FCT grant PTDC/MAT/115168/2009.
References
- 1.Braumann, C.A.: Introdução às Equações Diferenciais Estocásticas. Edições SPE, Lisboa (2005)Google Scholar
- 2.Braumann, C.A., Filipe, P.A., Carlos C., Roquete, C.J.: Growth of individuals in randomly fluctuating environments. In: Vigo-Aguiar, J., Alonso, P., Oharu, S., Venturino, E., Wade, B. (eds.) Proceedings of the International Conference in Computational and Mathematical Methods in Science e Engineering, Gijon, pp. 201–212 (2009)Google Scholar
- 3.Filipe, P.A.: Equações diferenciais estocásticas na modelação do crescimento individual em ambiente aleatório. Dissertação de Doutoramento, Universidade de Évora (2011)Google Scholar
- 4.Filipe, P.A., Braumann, C.A., Brites, N.M., Roquete, C.J.: Modelling animal growth in random environments: an application using nonparametric estimation. Biom. J. 52(5), 653–666 (2010)CrossRefMATHMathSciNetGoogle Scholar
- 5.Filipe, P.A., Braumann C.A., Roquete, C.J.: Multiphasic individual growth models in random environments. Methodol. Comput. Appl. Probab. 14(1), 49–56 (2012)CrossRefMATHMathSciNetGoogle Scholar
- 6.Ghikman, I.I., Skorohod, A.V.: Stochastic Differential Equations. Springer, Berlin (1991)Google Scholar
- 7.Karlin, S., Taylor, H.M.: A Second Course in Stochastic Processes. Academic, New York (1981)MATHGoogle Scholar