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Starting from the last decade of the twentieth century, most hospital Emergency Department (ED) budgets did not keep up with the demand for ED services made by growing populations and aging societies. Since labor consumes over 50% of the total monies invested in EDs and other healthcare systems, any downsizing, streamlining and reorganization plan needs to(More)
This paper presents a hybrid evolutionary algorithm (HEA) to solve heterogeneous fleet vehicle routing problems with time windows. There are two main types of such problems, namely the fleet size and mix vehicle routing problem with time windows (F) and the heterogeneous fixed fleet vehicle routing problem with time windows (H), where the latter, in(More)
In this paper we study the Multi-period Vehicle Routing Problem with Due dates (MVRPD), where customers have to be served between a release and a due date. Customers with due dates exceeding the planning period may be postponed at a cost. A fleet of capacitated vehicles is available to perform the distribution in each day of the planning period. The(More)
This paper introduces the fleet size and mix pollution-routing problem which extends the pollution-routing problem by considering a heterogeneous vehicle fleet. The main objective is to minimize the sum of vehicle fixed costs and routing cost, where the latter can be defined with respect to the cost of fuel and CO2 emissions, and driver cost. Solving this(More)
It has been around thirty years since the heterogeneous vehicle routing problem was introduced, and significant progress has since been made on this problem and its variants. The aim of this survey paper is to classify and review the literature on heterogeneous vehicle routing problems. The paper also presents a comparative analysis of the metaheuristic(More)
This paper describes an exact algorithm for a variant of the vehicle routing problem in which customer demands are stochastic. Demands are revealed upon arrival at customer locations. As a result, a vehicle may reach a customer and not have sufficient capacity to collect the realized demand. Such a situation is referred to as a failure. In this paper the(More)
This paper introduces the fleet size and mix location-routing problem with time windows (FSMLRPTW) which extends the location-routing problem by considering a heterogeneous fleet and time windows. The main objective is to minimize the sum of vehicle fixed cost, depot cost and routing cost. We present mixed integer programming formulations, a family of valid(More)