This paper considers a continuous-review, single-product production-inventory system with a constant replenishment rate, compound Poisson demands and lost-sales. Two objective functions that represent metrics of operational costs are considered: (1) the sum of the expected discounted inventory holding costs and lost-sales penalties, both over an infinite time horizon, given an initial inventory...

Time dependent energy tariffs are a matter of concern to managers in organisations, who need to rethink how to allocate resources to business processes so that they take into account energy costs. However, due to the time-dependent costs, the resource optimisation problem needs to be redesigned. In this paper we formalise the energy-aware resource allocation problem, including time-dependent va...

We extend Melitz (2003) to allow for both global and bilateral fixed export costs. If global (bilateral) export costs dominate, the average sales ratio (import sales per product variety/domestic sales per variety), decreases (increases) in variable (fixed) trade barriers, due to adjustment along the intensive (extensive) margin of trade. Using novel data on bilateral US movie exports we find th...

We study a single product inventory system with nonnegative setup cost in which the demand is a continuous random variable but orders are restricted to be integer valued. Optimal policies, when there are no setup costs, have a nice form. However, we show that, when the setup costs are nonzero, optimal policies may have a very counterintuitive form without any particular structure. We obtain a b...

We studied how the separation of dispensing and prescribing of medicines between pharmacies and clinics (the "separation system") can reduce internal medicine costs. To do so, we obtained publicly available data by searching electronic databases and official web pages of the Japanese government and non-profit public service corporations on the Internet. For Japanese medical institutions, partic...

In this paper, some multi-item imperfect production-inventory models without shortages for defective and deteriorating items with uncertain/ imprecise holding and production costs and resource constraint have been formulated and solved for optimal production. Here, the rate of production is assumed to be a function of time and considered as a control variable. Also the demand is time dependent ...

DYLP is a linear programming code implementing a dynamic simplex algorithm similar to that outlined by Padberg in [5]. The code attempts to maintain a reduced active constraint system by regularly purging loose constraints and variables with unfavourable reduced costs, and adding violated constraints and variables with favourable reduced costs. In abstract, the code alternates between primal an...

In this paper, we consider the control problem with the Average-Value-at-Risk (AVaR) criteria of the possibly unbounded L1-costs in infinite horizon on a Markov Decision Process (MDP). With a suitable state aggregation and by choosing a priori a global variable s heuristically, we show that there exist optimal policies for the infinite horizon problem for possibly unbounded costs. Mathematics S...

The costs of a clinical chemistry laboratory in a district general hospital were studied. The system used has certain advantages over the conventional Cooper Lybrand method. The time taken by technicians to perform tests was more variable than expected and the cost of sample collection was higher than process-cost for many tests. Indirect costs (overheads) were greater than direct costs and the...

A Variable Neighbourhood Search algorithm that employs new neighbourhoods is proposed for solving a task allocation problem whose main characteristics are: (i) each task requires a certain amount of resources and each processor has a capacity constraint which limits the total resource of the tasks that are assigned to it; (ii) the cost of solution includes fixed costs when using processors, tas...