Defence closure and job loss: The case of swan hunter on tyneside

Recently in this journal Hooper and Butler (1996) drew attention to the scale of job loss associated with restructuring in the defence sector in the aftermath of the Cold War. They noted that there is comparatively little knowledge of the experiences of workers following the closure of defence plants. This research communication attempts to shed further light on this issue by reporting the results of a survey of the experiences of former Swan Hunter shipyard workers who were made redundant after the firm went into receivership. The results confirm the complex but generally negative effect of redundancy on the workers involved.     

The inherent propensity toward peace or war embodied in weaponry

Thomas Schelling argues that armed adversaries face an inherent propensity toward peace or war embodied in their weaponry, geography and military organizations. Inherent propensity is the idea that there are characteristics embodied in the weapons that push adversaries toward peace or war, independent of the goals of the decision‐makers, the political disagreement between adversaries, and misperceptions about mutual resolve and hostility. We theoretically illustrate inherent propensity in conventional and nuclear arms settings using Lanchester and Intriligator war models. Our work extends the Intriligator‐Brito model, identifies when the competing Richardson and Intriligator‐Brito views of the relationship between arms races and war are correct, illustrates the stabilizing/destabilizing effects of alliances, and highlights the importance of arms quality control in the US‐USSR relationship.     

Using grasp to solve the component grouping problem

Component grouping problems, a type of set-partitioning problem, arise in a number of different manufacturing and material logistics application areas. For example, in circuit board assembly, robotic work cells can be used to insert components onto a number of different types of circuit boards. Each type of circuit board requires particular components, with some components appearing on more than one type. The problem is to decide which components should be assigned to each work cell in order to minimize the number of visits by circuit boards to work cells. We describe two new heuristics for this problem, based on so-called greedy random adaptive search procedures (GRASP). With GRASP, a local search technique is replicated many times with different starting points. The starting points are determined by a greedy procedure with a probabilistic aspect. The best result is then kept as the solution. Computational experiments on problems based on data from actual manufacturing processes indicate that these GRASP methods outperform, both in speed and in solution quality, an earlier, network-flow-based heuristic. We also describe techniques for generating lower bounds for the component grouping problem, based on the combinatorial structure of a problem instance. The lower bounds for our real-world test problems averaged within 7%-8% of the heuristic solutions. Similar results are obtained for larger, randomly generated problems. © 1994 John Wiley & Sons. Inc.     

Viability analysis: A formulation aid for all classes of network models

Nonviable network models have edges which are forced to zero flow simply by the pattern of interconnection of the nodes. The original nonviability diagnosis algorithm [4] is extended here to cover all classes of network models, including pure, generalized, pure processing, nonconserving processing, and generalized processing. The extended algorithm relies on the conversion of all network forms to a pure processing form. Efficiency improvements to the original algorithm are also presented.