A model for critical crack size estimation in fatigue failure of gun barrels

With repeated firing, fatigue cracks are produced in a gun barrel, and the barrel is no longer useful when a crack reaches a critical size. The initial crack size and the critical crack size, as well as the number of firings producing the critical crack size, may be considered as random variables. Assuming a proportional damage model for crack growth, a method for estimating the critical crack size distribution is presented. From these results, an estimate of the barrel life, or the residual barrel life once a crack of a given size is measured, can be obtained.     

An algorithm for optimal shipments with given frequencies

This article deals with the problem of minimizing the transportation and inventory cost associated with the shipment of several products from a source to a destination, when a finite set of shipping frequencies is available. A mixed-integer programming model—shown to be NP-hard—is formulated for that problem. The computational complexity of some similar models applied to different problems is also investigated. In particular, whereas the capacitated plant location problem with operational cost in product form is NP-hard, the simple plant location problem with the same characteristics can be solved in polynomial time. A branch-and-bound algorithm is finally worked out, and some computational results are presented. © 1996 John Wiley & Sons, Inc.     

Minimax trees,paths, and cut sets

The notions of minimax paths, trees, and cut sets are defined for undirected graphs; and relationships between these entities are established. Simple solution procedures based on these relationships are presented.     

Optimizing the US Navy's combat logistics force

We study how changes to the composition and employment of the US Navy combat logistic force (CLF) influence our ability to supply our navy worldwide. The CLF consists of about 30 special transport ships that carry ship and aircraft fuel, ordnance, dry stores, and food, and deliver these to client combatant ships underway, making it possible for our naval forces to operate at sea for extended periods. We have modeled CLF operations to evaluate a number of transforming initiatives that simplify its operation while supporting an even larger number of client ships for a greater variety of missions. Our input is an employment schedule for navy battle groups of ships operating worldwide, extending over a planning horizon of 90–180 days. We show how we use optimization to advise how to sustain these ships. We have used this model to evaluate new CLF ship designs, advise what number of ships in a new ship class would be needed, test concepts for forward at‐sea logistics bases in lieu of conventional ports, demonstrate the effects of changes to operating policy, and generally try to show whether and how the CLF can support planned naval operations. Published 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008     

Conflict circuit breakers in the Great Lakes Region of Africa

Conflict resolution in the African Great Lakes Region has been linked to the protocols and projects agreed upon at the Second International Conference on the Great Lakes Region (ICGLR). The ICGLR created a continental-wide framework of conflict circuit breakers focused on resolving the structural and surface situational causes of the 1996 to 2003 armed conflicts that drew in at least six nations and destabilised the entire region. The implementation of these protocols and projects will serve as a test for the African Great Lakes Region to move away from conflict and into a cooperation and development phase; however, the effort to bring peace, stability and development will face obstacles not only in the security sector, but also in developing infrastructure, civil society, and good governance. In summary, this article contends that peace in the Great Lakes Region will depend equally on two factors: internal governance and building civil society institutions, and focused regional interlocking circuit-breaking institutions.     

A Central Asian Security Paradigm: Russia and Uzbekistan

The Islamic Movement of Uzbekistan (IMU) is a Central Asian terrorist organization that has carried out series of attacks in countries like Uzbekistan, Kyrgyzstan and Tajikistan for years. With the ultimate goal of creating a Central Asian Caliphate, the IMU, even in its current weak state, is a regional threat. A military solution to this problem appears to be the likely answer. Regional powers like the Russian Federation and China should be militarily involved in Uzbekistan, along with Uzbek and neighboring forces in order to defeat the IMU militarily. This will promote greater integration among these countries and eliminate a violent organization which could become a destabilizing factor if not dealt with.     

A war of attrition: Sri Lanka and the Tamil Tigers

After decades of fighting, the secessionist war between the government of Sri Lanka and the secessionist movement known as the Tamil Tigers of Eelam continues. Military operations have failed to achieve a decisive victory over the other side. This article aims to prove that the Sri Lankan civil war should be regarded as a war of attrition, as military actions have failed, and possibly will continue to fail, to produce a victor.     

IED casualties mask the real problem: it's us

Casualty figures suggest that the US/Allied Counter Improvised Explosive Device (C-IED) policy and the present allocation of national assets, resources, and intellectual capital have not been very successful. A number of explanations for why this has been the case are discussed and critiqued here.