A simulated annealing approach to the cyclic staff-scheduling problem

This article presents the application of a simulated annealing heuristic to an NP-complete cyclic staff-scheduling problem. The new heuristic is compared to branch-and-bound integer programming algorithms, as well as construction and linear programming-based heuristics. It is designed for use in a continuously operating scheduling environment with the objective of minimizing the number of employees necessary to satisfy forecast demand. The results indicate that the simulated annealing-based method tends to dominate the branch-and-bound algorithms and the other heuristics in terms of solution quality. Moreover, the annealing algorithm exhibited rapid convergence to a low-cost solution. The simulated annealing heuristic is executed in a single program and does not require mathematical programming software. © 1993 John Wiley & Sons, Inc.     

Level crossing analysis of priority queues and a conservation identity for vacation models

The two purposes of this article are to illustrate the power and simplicity of level crossing analysis and to present a conservation identity for M/G/1 priority queues with server vacations. To illustrate the use of level crossing analysis we apply it to preemptive (resume) priority M/G/1 queues with single- and multiple-server vacations considered by Kella and Yechiali (1986) and to non-preemptive priority M/M/c queues considered by Kella and Yechiali (1985). The conservation identity presented here states that the ratios of mean waiting times in an M/G/1 queue with and without server vacation policies are independent of the service discipline for first come first served, shortest processing time, shortest processing time within generations and non-preemptive priority service disciplines.     

A theoretical justification for an increasing average failure rate strength distribution in fibrous composites

A general model for the failure of fibrous composite materials is described. It is shown to contain some of the well-known models in the literature. The composite material is viewed as a coherent system of independent identically distributed component strengths. Under the assumption that the applied load is redistributed “homotonically” to the unfailed components upon the failure of a component (an individual fiber segment) and that the distributions of component strengths are IFRA, it is shown that the system (composite) strength distribution is also IFRA. Examples are given using carbon reinforced composite data to illustrate the IFRA property.     

Exploiting self‐canceling demand point aggregation error for some planar rectilinear median location problems

When solving location problems in practice it is quite common to aggregate demand points into centroids. Solving a location problem with aggregated demand data is computationally easier, but the aggregation process introduces error. We develop theory and algorithms for certain types of centroid aggregations for rectilinear 1‐median problems. The objective is to construct an aggregation that minimizes the maximum aggregation error. We focus on row‐column aggregations, and make use of aggregation results for 1‐median problems on the line to do aggregation for 1‐median problems in the plane. The aggregations developed for the 1‐median problem are then used to construct approximate n‐median problems. We test the theory computationally on n‐median problems (n ≥ 1) using both randomly generated, as well as real, data. Every error measure we consider can be well approximated by some power function in the number of aggregate demand points. Each such function exhibits decreasing returns to scale. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 614–637, 2003.     

Enhancing Political Cohesion in NATO during the 1950s or: How it Learned to Stop Worrying and Love the (Tactical) Bomb

This article argues that the perceived need by NATO to nurture political cohesion within the Alliance during the 1950s resulted in the adoption of strategic concepts that were out-of-step with the military environment in which it was operating. It maintains that the Alliance acquiesced to American leadership on nuclear issues which led to the development of tactical nuclear capabilities at the expense of conventional war-fighting capabilities for the defence of the European Central Front. This resulted in a strategic concept that enhanced political cohesion but was militarily unviable.     

IF YOU WANT IT DONE RIGHT,DO IT YOURSELF

Some have argued that the transatlantic rancor over the Iraq war made cooperation, especially on nonproliferation, unlikely. In contrast, this article, documents post-invasion instances of nonproliferation cooperation, with particular emphasis on the Proliferation Security Initiative and the EU-3 Initiative—the British, French, and German negotiations with Iran over its suspected nuclear activities. In addition to documenting French and British participation in these initiatives, the article analyzes why they have chosen to participate and argues that France and Britain have participated in both efforts because they are committed to avoiding future Iraq-like preventive wars.     

Estimated UK employment dependent on ministry of defence expenditure and defence exports

The Ministry of Defence (MOD) has published estimates of the number of average full‐time UK industry employees dependent on MOD expenditure and defence exports for a number of years. This paper provides the outcome of a recent review of the process used. The method of deriving MOD and defence export final demand vectors, and calculating from these estimates of direct employment (i.e. that in supplying companies) and indirect employment (i.e. that incurred through the supply chain) are described. Difficulties with the data are explored. Alternative approaches, methods used in other countries and challenges posed by changing MOD administrative systems are briefly discussed.     

The demand for military spending in developing countries: A dynamic panel analysis∗

Estimating demand functions for developing countries before and after the end of the Cold War, Dunne and Perlo-Freeman (2003) found little evidence of any change in the underlying relationship. One concern with their analysis was that the use of cross-section averages might have obscured important time series effects. This paper deals with this issue by analysing their data using static and dynamic panel data methods. This produces evidence of a change in relationship and suggests that the focus in the literature on cross-section analyses has indeed limited our understanding of important dynamic processes at work within countries.     

Military Debt: Perspectives from the Experience of Arab Countries

The sectoral production function model of Feder (1983) has been widely used to examine the link between defence spending and economic growth. In this paper, the model, for which too much has been claimed in some past work, is examined, and the case is made for using growth in real non‐defence output rather than growth in real aggregate output (inclusive of military spending) as the dependent variable. Attention is restricted to a small group of OECD countries for which reliable labour force and capital stock (as well as defence) data are obtainable. With non‐defence output as the dependent variable and using only high quality data, no evidence in favour of the underconsumptionist (as opposed to the defence as a burden) position is found.