What made American Civil War soldiers fight?

James M. McPherson, For Cause and Comrades: Why Men Fought in the Civil War. New York: Oxford University Press, 1997. Pp.xv + 237, appendix, notes, index. £20 (cloth); $13.95 (paper). ISBN 0–10–512499–5     

Algorithms for solving the conditional covering problem on paths

Consider the conditional covering problem on an undirected graph, where each node represents a site that must be covered by a facility, and facilities may only be established at these nodes. Each facility can cover all sites that lie within some common covering radius, except the site at which it is located. Although this problem is difficult to solve on general graphs, there exist special structures on which the problem is easily solvable. In this paper, we consider the special case in which the graph is a simple path. For the case in which facility location costs do not vary based on the site, we derive characteristics of the problem that lead to a linear‐time shortest path algorithm for solving the problem. When the facility location costs vary according to the site, we provide a more complex, but still polynomial‐time, dynamic programming algorithm to find the optimal solution. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

Manpower allocation with time windows and job‐teaming constraints

In this work, we study manpower allocation with time windows and job‐teaming constraints. A set of jobs at dispersed locations requires teams of different types of workers where each job must be carried out in a preestablished time window and requires a specific length of time for completion. A job is satisfied if the required composite team can be brought together at the job's location for the required duration within the job's time window. The objective is to minimize a weighted sum of the total number of workers and the total traveling time. We show that construction heuristics used with simulated annealing is a good approach to solving this NP‐hard problem. In experiments, this approach is compared with solutions found using CPLEX and with lower bounds obtained from a network flow model. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

Keeping Nothing Secret: United Kingdom Chemical Warfare Policy in the 1960s

After renouncing an offensive chemical warfare programme in 1956, the UK Cabinet Defence Committee decided in 1963 to re-acquire a chemical warfare retaliatory capability. This article describes how the re-acquisition decision was engendered by a combination of novel research findings, changes in strategic thinking, new intelligence and pressures from NATO. Despite the 1963 decision, no new chemical weapons capability was acquired by the UK and information that Britain lacked a stockpile of chemical weapons was eventually leaked to the public, initiating a fierce debate between ministries over the significance of this leak. This paper argues that non-existent technology is equally problematic for government secrecy, and equally consequential for government action, as what exists. Furthermore, actors' different interpretations of what constituted a secret, point towards a more subtle understanding of secrecy than simply construing it as the hiding or uncovering of items of information.     

A m‐parallel crane scheduling problem with a non‐crossing constraint

In this paper, we study a m‐parallel machine scheduling problem with a non‐crossing constraint motivated by crane scheduling in ports. We decompose the problem to allow time allocations to be determined once crane assignments are known and construct a backtracking search scheme that manipulates domain reduction and pruning strategies. Simple approximation heuristics are developed, one of which guarantees solutions to be at most two times the optimum. For large‐scale problems, a simulated annealing heuristic that uses random neighborhood generation is provided. Computational experiments are conducted to test the algorithms. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007.