Redundant spares allocation to reduce reliability costs

The problem considered here is the optimal selection of the inventory of spares for a system built from two kinds of modules, the larger of which can be connected so it performs the role of the smaller one. The optimal inventory is the least costly one which achieves a specified probability that the spares will not be exhausted over the design lifetime. For some costs and failure rates it is most economical to use the larger module for both roles, due to the resulting increase in flexibility in the deployment of a single type of spare module. Both analytical and simulation methods have been used to study this problem.     

A facility reliability problem: Formulation,properties, and algorithm

Having a robustly designed supply chain network is one of the most effective ways to hedge against network disruptions because contingency plans in the event of a disruption are often significantly limited. In this article, we study the facility reliability problem: how to design a reliable supply chain network in the presence of random facility disruptions with the option of hardening selected facilities. We consider a facility location problem incorporating two types of facilities, one that is unreliable and another that is reliable (which is not subject to disruption, but is more expensive). We formulate this as a mixed integer programming model and develop a Lagrangian Relaxation‐based solution algorithm. We derive structural properties of the problem and show that for some values of the disruption probability, the problem reduces to the classical uncapacitated fixed charge location problem. In addition, we show that the proposed solution algorithm is not only capable of solving large‐scale problems, but is also computationally effective. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Field test and probabilistic analysis of irregular steel debris casualty risks from a person-borne improvised explosive device

Person-borne improvised explosive devices (PBIEDs) are often used in terrorist attacks in Western countries. This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people exposed to this hazard. An explosive field test with a typical PBIED composed of a plastic explosive charge and steel nut enhancements was performed to record initial fragment behaviour, including positions, velocity, and trajectory angles. These data were used to predict the full trajectory of PBIED fragments using a probabilistic analysis. In the probabilistic analyses a probability of fatality or serious injury was computed. Based on the results presented, many practical conclusions can be drawn, for instance, regarding safe evacuation distances if a person were exposed to a suspected PBIED.     

THE F‐35 JOINT STRIKE FIGHTER AS A SOURCE OF INNOVATIon AND EMPLOYMENT: SOME INTERIM RESULTS

The F‐35 Joint Strike Fighter (JSF) programme is important for innovation in the Dutch economy and also contributes to other programmes in the aerospace industry (spin‐off) and other industries (spillover). On top of the expected value of US$9.2 billion in development and production, based on interviews with 10 companies and research institutes, an expected spin‐off of US$1.1 billion and an expected spillover of US$120 million will result. In addition, over 23,000 man‐years are associated with the activities in the development and production of the JSF. This study excludes the large and labour‐intensive Maintenance, Repair and Overhaul (MRO) activities. Further validation of data and an update of current results is planned for 2006.     

MIDDLE EAST NONPROLIFERATION

The Middle East is a crucial region for the global nonproliferation regime. In 2010, the state parties to the Treaty on the Non-Proliferation of Nuclear Weapons proposed a conference on a Middle East Weapons of Mass Destruction-Free Zone. The nuclear weapon-free zone model, on which this idea builds, has achieved important results in other regions, but faces especially stark challenges in the Middle East. However, the attempt to apply the boldly imaginative zone approach to the Middle East holds promise for building a more inclusive dialogue on nonproliferation and regional security.