Aircraft routing under the risk of detection

The deterministic problem for finding an aircraft's optimal risk trajectory in a threat environment has been formulated. The threat is associated with the risk of aircraft detection by radars or similar sensors. The model considers an aircraft's trajectory in three‐dimensional (3‐D) space and represents the aircraft by a symmetrical ellipsoid with the axis of symmetry directing the trajectory. Analytical and discrete optimization approaches for routing an aircraft with variable radar cross‐section (RCS) subject to a constraint on the trajectory length have been developed. Through techniques of Calculus of Variations, the analytical approach reduces the original risk optimization problem to a vectorial nonlinear differential equation. In the case of a single detecting installation, a solution to this equation is expressed by a quadrature. A network optimization approach reduces the original problem to the Constrained Shortest Path Problem (CSPP) for a 3‐D network. The CSPP has been solved for various ellipsoid shapes and different length constraints in cases with several radars. The impact of ellipsoid shape on the geometry of an optimal trajectory as well as the impact of variable RCS on the performance of a network optimization algorithm have been analyzed and illustrated by several numerical examples. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

Homes for heroes? Assessing the impact of the UK’s Military Covenant

The British Military Covenant can be located in and from many sources and from 2011 onwards in primary legislation. This article argues that the provision of military housing amounts to an early test of how the military covenant is understood and used by those involved in defence policy, and those in the armed forces affected by it. It finds that housing was a prominent feature of how service personnel understood how they were valued, but was not explicitly understood as a covenant issue by those personnel or the officials in charge of the Defence Estates. We locate three reasons for this: (1) the covenant has been poorly translated from aspiration into policy practice, (2) the covenant is unevenly understood across its stakeholders which has the effect of generating disappointment through misaligned expectations, (3) those engaged in the reform process surrounding the Defence Infrastructure Organisation (DIO) saw the covenant as a means to energise reform. Ultimately housing was seen as a dry and technocratic business area and thus an issue ripe for being refracted through the covenant was ultimately left outside of its remit.     

A simulated port facility in a theatre of operations

A hypothetical port facility in a theatre of operations is modeled and coded in a special purpose simulation language, for the purpose of conducting simulation experiments on a digital computer. The experiments are conducted to investigate the resource requirements necessary for the reception, discharge, and clearance of supplies at the port. Queue lengths, waiting times, facility utilizations, temporary storage levels, and ship turn-around times are analyzed as functions of transportation and cargo handling resources, using response surface methodology. The resulting response surfaces are revealing in regard to the sensitivity of port operations to transportation resource levels and the characteristics of the port facility's load factor. Two specific conclusions of significant value are derived. First, the simulation experiments clearly show that the standard procedures for determining discharge and clearance capacities take insufficient account of the effects of variability. Second, the response surfaces for ship turn-around times and temporary storage levels indicate that an extremely steep gradient exists as a function of troop levels.