A team from the Naval Postgraduate School conducted a trade-off analysis of in-sourcing (i.e., make) versus outsourcing (i.e., buy) the production of legacy parts for ship maintenance and modernization with a focus on cost savings given the need for cost-effective sustainment. The purpose of the study was to compare the make/buy trade-off for a comparison of implementing 3DLST, 3DP, and CPLM fo...

A simulation model for evaluating the performance of an emergency response fleet of an electric utility company is presented. The proposed model considers the spatial, temporal, and severity distribution of calls and has the capability to simulate alternative configurations of service districts and dispatching policies of the emergency response fleet. A nonstadonary Poisson process is used to s...

We develop a model to determine the optimal structure and size of a rail car fleet at a chemical company under uncertainty in demand and travel times as well as substitution between rail car types. First, we formulate an MILP model that accounts for the substitution relations between the types and minimizes the total direct rail car cost under given rail car availability constraints and a prede...

If your irrigation system is not performing as efficiently as you would like then it may be time to consider updating. This can be done by renewing sprinklers, installing a more advanced control panel, renewing that worn out pump — or a complete redesign of the whole system using modern technology. If you already have Weather-matic equipment installed, Prime offers a full repair and maintenance...

In This Issue In This Issue Ready…set…fuse he fusion of two lipid membranes underlies a huge range of biological phenomena, from infection by enveloped viruses to the secretion of cellular proteins , but a central aspect of membrane fusion has remained mysterious: do the T proteins that mediate fusion act cooperatively or independently? On page 833, Markovic et al. argue that teamwork is the or...

Given a flight schedule, which is a set of flight segments with specified departure and arrival times, and a set of aircraft:, the fleet assignment problem is to determine which aircraft type should fly each flight segment. The objective is to maximize revenue minus operating costs. In the basic fleet assignment problem considered by Hane et al. (1995) a daily, domestic fleet assignment prohlem...

The growth of AVL (Automatic Vehicle Location) systems leads to huge amount of data about different parts of bus fleet (buses, stations, passenger, etc.) which is very useful to improve bus fleet efficiency. In addition, by processing fleet and passengers’ historical data it is possible to detect passenger’s behavioral patterns in different parts of the day and to use it in order to improve fle...

In this paper we present a local search heuristic method for an integrated airline scheduling, fleeting and pricing model. The integrated model simultaneously optimizes the decisions of schedule design, fleet assignment, seat allocation, pricing and considers passengers’ spill and recapture. The resulting problem is a mixed integer non-convex problem due to the explicit representation of a dema...

OBJECTIVES In the year 2000, as part of the process for setting New Zealand road safety targets, a projection was made for a reduction in social cost of 15.5 percent associated with improvements in crashworthiness, which is a measure of the occupant protection of the light passenger vehicle fleet. Since that document was produced, new estimates of crashworthiness have become available, allowing...