### Skapa referens, olika format (klipp och klistra)

**Harvard**

Patriksson, M., Strömberg, A. och Wojciechowski, A. (2011) *The opportunistic replacement problem with individual component lives*.

** BibTeX **

@unpublished{

Patriksson2011,

author={Patriksson, Michael and Strömberg, Ann-Brith and Wojciechowski, Adam},

title={The opportunistic replacement problem with individual component lives},

abstract={We consider an extension of the opportunistic replacement problem, which has been studied by Dickman, Epstein and Wilamowsky [3], Andréasson [2], and Andréasson et al. [1], that allows the individuals of the same component to have nonidentical lives. Formulating and solving this problem defines a first step towards solving the opportunistic replacement problems with uncertain component lives. We show that the problem is NP-hard even with time independent costs, and present two mixed integer linear programming models for the problem. We show that in model I the binary requirement on the majority of the variables can be relaxed; this is in contrast to model II and Andréasson’s [2] model. We remove all superfluous variables and constraints in model I and show that the remaining constraints are facet inducing. We also utilize a linear transformation of model I to obtain a stronger version of model II, model II+, that inherits the polyhedral properties of model I. Numerical experiments show that the solution time of model I is significantly lower than the solution times of both model II and Andréasson’s model. It is also somewhat lower than the solution time of model II+.},

year={2011},

note={26},

}

** RefWorks **

RT Unpublished Material

SR Print

ID 154951

A1 Patriksson, Michael

A1 Strömberg, Ann-Brith

A1 Wojciechowski, Adam

T1 The opportunistic replacement problem with individual component lives

YR 2011

AB We consider an extension of the opportunistic replacement problem, which has been studied by Dickman, Epstein and Wilamowsky [3], Andréasson [2], and Andréasson et al. [1], that allows the individuals of the same component to have nonidentical lives. Formulating and solving this problem defines a first step towards solving the opportunistic replacement problems with uncertain component lives. We show that the problem is NP-hard even with time independent costs, and present two mixed integer linear programming models for the problem. We show that in model I the binary requirement on the majority of the variables can be relaxed; this is in contrast to model II and Andréasson’s [2] model. We remove all superfluous variables and constraints in model I and show that the remaining constraints are facet inducing. We also utilize a linear transformation of model I to obtain a stronger version of model II, model II+, that inherits the polyhedral properties of model I. Numerical experiments show that the solution time of model I is significantly lower than the solution times of both model II and Andréasson’s model. It is also somewhat lower than the solution time of model II+.

LA eng

OL 30