To catch an intruder: Part A—uncluttered scenario

We analyze an interdiction scenario where an interceptor attempts to catch an intruder as the intruder moves through the area of interest. A motivating example is the detection and interdiction of drug smuggling vessels in the Eastern Pacific and Caribbean. We study two models in this article. The first considers a nonstrategic target that moves through the area without taking evasive action to avoid the interdictor. We determine the optimal location the interceptor should position itself to best respond when a target arrives. The second model analyzes the strategic interaction between the interceptor and intruder using a Blotto approach. The intruder chooses a route to travel on and the interceptor chooses a route to patrol. We model the interaction as a two‐player game with a bilinear payoff function. We compute the optimal strategy for both players and examine several extensions. © 2017 Wiley Periodicals, Inc. Naval Research Logistics, 64: 29–40, 2017     

Production scheduling with history‐dependent setup times

We consider a parallel‐machine scheduling problem with jobs that require setups. The duration of a setup does not depend only on the job just completed but on a number of preceding jobs. These setup times are referred to as history‐dependent. Such a scheduling problem is often encountered in the food processing industry as well as in other process industries. In our model, we consider two types of setup times—a regular setup time and a major setup time that becomes necessary after several “hard‐to‐clean” jobs have been processed on the same machine. We consider multiple objectives, including facility utilization, flexibility, number of major setups, and tardiness. We solve several special cases assuming predetermined job sequences and propose strongly polynomial time algorithms to determine the optimal timing of the major setups for given job sequences. We also extend our analysis to develop pseudopolynomial time algorithms for cases with additional objectives, including the total weighted completion time, the total weighted tardiness, and the weighted number of tardy jobs. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Determining newspaper marketing zones using contiguous clustering

We develop a heuristic procedure for partitioning graphs into clusters of nodes such that each cluster of nodes induces a connected subgraph with the objective of minimizing the differences within clusters as measured by the total differences between all pairs of nodes of a cluster. We apply our procedure to determine optimal delivery zones for community sections of a major newspaper while including a number of operational constraints. Our results demonstrate a 18–56% improvement in the total differences within the zones designed over the usual intuitive heuristics. Given the magnitude of the revenue generated by larger local newspapers through zoning, our method demonstrates how better zoning can significantly enhance the value of segmentation. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

Optimal joint preventive maintenance and production policies

We study joint preventive maintenance (PM) and production policies for an unreliable production‐inventory system in which maintenance/repair times are non‐negligible and stochastic. A joint policy decides (a) whether or not to perform PM and (b) if PM is not performed, then how much to produce. We consider a discrete‐time system, formulating the problem as a Markov decision process (MDP) model. The focus of the work is on the structural properties of optimal joint policies, given the system state comprised of the system's age and the inventory level. Although our analysis indicates that the structure of optimal joint policies is very complex in general, we are able to characterize several properties regarding PM and production, including optimal production/maintenance actions under backlogging and high inventory levels, and conditions under which the PM portion of the joint policy has a control‐limit structure. In further special cases, such as when PM set‐up costs are negligible compared to PM times, we are able to establish some additional structural properties. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

A shifting bottleneck heuristic for minimizing the total weighted tardiness in a job shop

We present a shifting bottleneck heuristic for minimizing the total weighted tardiness in a job shop. The method decomposes the job shop into a number of single‐machine subproblems that are solved one after another. Each machine is scheduled according to the solution of its corresponding subproblem. The order in which the single machine subproblems are solved has a significant impact on the quality of the overall solution and on the time required to obtain this solution. We therefore test a number of different orders for solving the subproblems. Computational results on 66 instances with ten jobs and ten machines show that our heuristic yields solutions that are close to optimal, and it clearly outperforms a well‐known dispatching rule enhanced with backtracking mechanisms. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 1–17, 1999     

Optimal sensor placement for underwater threat detection

The optimization framework for optimal sensor placement for underwater threat detection has been developed. It considers single‐period and multiperiod detection models, each of which includes two components: detection algorithm and optimization problem for sensor placement. The detection algorithms for single‐period and multiperiod models are based on likelihood ratio and sequential testing, respectively. For the both models, the optimization problems use the principle of superadditive coverage, which is closely related to energy‐based and information‐based approaches. An algorithm for quasi‐regular sensor placement approximating solutions to the optimization problems has been developed based on corresponding continuous relaxations and a criterion for its applicability has been obtained. Numerical experiments have demonstrated that the algorithm consistently outperforms existing optimization techniques for optimal sensor placement.© 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

China’s Search for a ‘Strategic Air Force’

Once dismissed by many outside observers, the Chinese People’s Liberation Army Air Force (PLAAF) has undergone an impressive transformation over the past two decades, emerging as one of the world’s premier air forces. As it continues to modernize, it is focused on becoming a ‘strategic air force.’ PLAAF strategists suggest this means it should play a decisive role in protecting Chinese national interests, field modern capabilities commensurate with China’s standing as a major power, and enjoy the institutional status befitting its role as a ‘strategic service,’ an important consideration given the historical dominance of the ground force in China’s military.     

European defence industry consolidation and domestic procurement bias

How have European cross-border defence industrial mergers and acquisitions affected domestic procurement bias among the major EU powers? This article departs from the findings of Andrew Moravcsik more than two decades ago suggesting that major West European states had no ingrained preferences for defence industrial autarchy. When cross-national armament projects were derailed, this could be attributed to political efforts of national defence industrial champions favouring purely domestic projects. As former national champions join pan-European defence groups, their preferences are likely modified. Does this shift procurement towards non-European “off-the-shelf” solutions which, according to Moravcsik, are favoured by defence departments? Or does it give impetus to a stronger preference for European as opposed to domestic systems? In this article, procurement patterns in the aftermath of cross-border defence industry consolidation will be analysed. Procurement bias is assessed in two industry segments characterised by pervasive consolidation.     

NUCLEAR ATTRIBUTION AS DETERRENCE

Recently, post-explosion nuclear forensics, or nuclear attribution, has gained a new spotlight within the nuclear weapons scientific and policymaking community. Academics are beginning to ask whether post-explosion forensics might create a replacement for an international nonproliferation regime, or at least offer a fallback option to deter states and individuals from selling nuclear materials. This paper examines current attribution technology from unclassified literature and finds the technology to be well developed but not foolproof, such that nuclear attribution currently provides little deterrent value. If current capabilities were publicized more thoroughly and if the post-explosion process of assessing the evidence were internationalized, states and intermediate actors might be deterred more effectively. Developing a nuclear fingerprint database is also discussed. While useful, its impact on deterrence would be minimal.