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作者：Fry, MJ; Magazine, MJ; Rao, US
作者单位：University System of Ohio; University of Cincinnati
摘要：We examine the problem of determining the annual staffing level that minimizes total expected costs for a fire department, subject to minimum service-level-based staffing requirements. We develop a quantitative model that allows for stochastic temporary absences, permanent wastage, and limited hiring opportunities, and takes into account the unique firefighter work schedule. Our model is reminiscent of traditional newsvendor-type inventory models, but where the uncertainty is dependent on the ...
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作者：Ghiani, G; Laporte, G; Semet, F
作者单位：Universite de Montreal; University of Salento; Universite de Montreal; HEC Montreal; Centre National de la Recherche Scientifique (CNRS); Universite Polytechnique Hauts-de-France
摘要：The black and white traveling salesman problem (BWTSP) is defined on a graph G whose vertex set is partitioned into black and white vertices. The aim is to design a shortest Hamiltonian tour on G subject to cardinality and length constraints: both the number of white vertices as well as the length of the tour between two consecutive black vertices are bounded above. The BWTSP has applications in airline scheduling and in telecommunications. This paper proposes an integer linear formulation for...
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作者：Önal, H; Briers, RA
作者单位：University of Illinois System; University of Illinois Urbana-Champaign; Edinburgh Napier University
摘要：Spatial considerations are important in conservation reserve design. A particularly important spatial requirement is the connectivity of selected sites. Direct connections between reserve sites increase the likelihood of species persistence by allowing dispersal and colonization of other areas within the network without species having to leave the reserve. The conventional set-covering and maximal-covering formulations of the reserve selection problem assume that species representation is the ...
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作者：Fox, EJ; Metters, R; Semple, J
作者单位：Southern Methodist University; Emory University
摘要：We analyze a periodic-review inventory model where the decision maker can buy from either of two suppliers. With the first supplier, the buyer incurs a high variable cost but negligible fixed cost; with the second supplier, the buyer incurs a lower variable cost but a substantial fixed cost. Consequently, ordering costs are piecewise linear and concave. We show that a reduced form of generalized (s, S) policy is optimal for both finite and (discounted) infinite-horizon problems, provided that ...
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作者：Geunes, J; Romeijn, HE; Taaffe, K
作者单位：State University System of Florida; University of Florida; Clemson University
摘要：Past requirements-planning research has typically assumed that the firm's demands are determined prior to production planning. In contrast, we explore a single-stage planning model that implicitly decides, through pricing decisions, the demand levels the firm should satisfy in order to maximize contribution to profit. We briefly discuss solution methods and properties for these problems when production capacities are unlimited. The key result of this work is a polynomial-time solution approach...
