REGIONAL PERSPECTIVES ON LOW NUCLEAR NUMBERS

President Barack Obama has outlined a course toward lower numbers of US nuclear weapons. Much attention has been paid to the US-Russian context, where deterrence is believed to be basically stable and conditions ripe for gradually reducing arsenals on both sides. But considerably less attention has been paid to the possible implications of lower nuclear numbers on other regions of the world and the reactions of both adversaries and US allies. If nuclear reductions are to be stabilizing and beneficial to security, reassurance and strengthened nonproliferation efforts in various regions need to accompany nuclear cuts. But the specific problems and remedies across regions vary. This article summarizes the results of a multi-author study. It concludes that regions with US allies and formal extended deterrence pledges may pose more vexing problems than those areas of the world without such close allies or commitments.     

Using container inspection history to improve interdiction logistics for illicit nuclear materials

Strengthening the United States' ability to prevent adversaries from smuggling nuclear materials into the country is a vital and ongoing issue. The prospect of additional countries, such as Iran, obtaining the know‐how and equipment to produce these special nuclear materials in the near future underscores the need for efficient and effective inspection policies at ports and border crossings. In addition, the reduction of defense and homeland security budgets in recent years has made it increasingly important to accomplish the interdiction mission with fewer funds. Addressing these complications, in this article, we present a novel two‐port interdiction model. We propose using prior inspection data as a low‐cost way of increasing overall interdiction performance. We provide insights into two primary questions: first, how should a decision maker at a domestic port use detection data from the foreign port to improve the overall detection capability? Second, what are potential limitations to the usefulness of prior inspection data—is it possible that using prior data actually harms decision making at the domestic port? We find that a boundary curve policy (BCP) that takes into account both foreign and domestic inspection data can provide a significant improvement in detection probability. This BCP also proves to be surprisingly robust, even if adversaries are able to infiltrate shipments during transit. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 433‐448, 2013     

Asymptotic analysis of periodic policies for the inventory routing problem

In this article, a distribution system is studied where the sum of transportation and inventory costs is to be minimized. The inventory holding cost is assumed to be the same for all retailers. A fixed partition (FP) periodic policy is proposed with tight asymptotic worst‐case performance of 3/2 with respect to the best possible policy. This bound cannot be improved in the class of FP periodic policies. In partition‐based PB policies, the retailers are first partitioned into sets and then the sets are grouped in such a way that sets of retailers within a group are served together at selected times. A PB periodic, policy is presented with tight worst‐case asymptotic performance of with respect to the best possible policy. This latter performance improves the worst‐case asymptotic performance of of the previously best known policy for this problem. We also show that the proposed PB periodic policy has the best worst‐case asymptotic performance within the class of PB policies. Finally, practical heuristics inspired by the analyzed policies are designed and tested. The asymptotic worst–case performances of the heuristics are shown to be the same of those of the analyzed policies. Computational results show that the heuristics suggested are less than 6.4% on average from a lower bound on the optimal cost when 50 or more retailers are involved. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 00: 000–000, 2013     

Inequality‐based reliability estimates for complex systems

Full‐system testing for large‐scale systems is often infeasible or very costly. Thus, when estimating system reliability, it is desirable to use a method that uses subsystem tests, which are often less expensive and more feasible. This article presents a method for bounding full‐system reliabilities based on subsystem tests and, if available, full‐system tests. The method does not require that subsystems be independent. It accounts for dependencies through the use of certain probability inequalities. The inequalities provide the basis for valid reliability calculations while not requiring independent subsystems or full‐system tests. The inequalities allow for test information on pairwise subsystem failure modes to be incorporated, thereby improving the bound on system reliability. We illustrate some of the properties of the estimates via an example application. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

The German campaign in Norway 1940 as a joint operation

The German invasion in Norway in April 1940 was unique in that it was the first major ‘triphibious’ campaign. It was an operation that was equally dependent upon naval, air and ground forces for success. Norway had long been of interest to German strategists, especially naval thinkers. However, no serious Wehrmacht plans for occupying Norway were even started until December 1939. A small group of staff officers of the three services put together a comprehensive plan in a matter of weeks. The article examines the effectiveness of the German interservice co‐operation and OKW leadership in a very tough and close run campaign. Although there were numerous problems, interservice co‐operation was fairly effective at the tactical and operational levels. Indeed, the Germans won the campaign largely because their services worked together much better than their Allied opponents.