Review of mathematical models for sow herd management

This paper is a survey of the different sow models described in literature, which made use of different mathematical methodologies, and were intended for sow herd management. Models were discussed under a wide classification, that is, simulation and optimisation. The latter included linear programming and dynamic programming with Markov decision models and optimal control as major representative models. In a first stage we recalled general traits and modelling foundations of herd management models and later, different aspects of sow herd models published up to now were reviewed. Special attention is paid to main variables, source of parameters, validation, output and intended use. Most of such models have been developed as research tools and teaching aids. Actually, the increasing ability to represent complex systems is not corresponded with an augmentation of decision support tools including such complex models in field conditions. Thus, a need of new proposals dealing with transient situations and non-time homogeneous parameters was detected. The inclusion of variability-risk features and multicriteria decision methods was also of interest for practical purposes. Actual changes in the pig sector lead to expect new management herd models, in particular considering more than one herd at a time.The author wish to acknowledge the financial support of the Spanish Research Program (CYCIT MTM2005-09362-C03-02)

Handover Optimality in Heterogeneous Networks

This paper introduces a new theoretical framework for optimal handover procedures in heterogeneous networks by devising the novel fractional Gittins indices, which are dynamical priorities whose values can be statically associated to the decision states of evolving processes representing handover alternatives. The simple policy of activating at any time the one process currently at highest priority optimizes the bandwidth of a handover, if all other inactive processes remain idle. However, numerical evidence shows that in practice this condition can be relaxed for a wide range of handover models, because the bandwidth actually achieved by the policy never deviates for more than 12% from the optimally achievable bandwidth and remains in median within a deviation of 2% from this optimum.Comment: accepted by IEEE 5G World Forum 201