Visibility probabilities on line segments in three-dimensional spaces subject to random poisson fields of obscuring spheres

The methodology of determining simultaneous visibility probabilities and points on line segments is extended to problems of three-dimensional spaces, with Poisson random fields of obscuring spheres. Required functions are derived analytically and a numerical example is given for a special case of a standard Poisson field, with uniform distribution of sphere diameters.     

A general age replacement model with minimal repair

A general age replacement is introduced which incorporates minimal repair, planned and unplanned replacements, and costs which depend on time. Finite and infinite horizon results are obtained. Various special cases are considered. Furthermore, a shock model with general cost structure is considered.     

Casualty Rates of US Military Personnel During the Wars in Iraq and Afghanistan

Abstract

In Operation Iraqi Freedom, which ended in August 2010, nearly 3500 hostile deaths occurred among US military personnel and 32,000 more were wounded in action (WIA). More than 1800 hostile deaths occurred during Operation Enduring Freedom (in and around Afghanistan) through 2014 and about 20,000 were WIA. A larger proportion of wounded personnel survived in Iraq and Afghanistan than during the Vietnam War, but the increased survival rates were not as high as some studies have asserted. The survival rates were 90.2% in Iraq and 91.6% in Afghanistan, compared with 86.5% in Vietnam. The casualty rates varied between the conflicts in Iraq and Afghanistan and before, during, and after the respective surges. Amputation rates are difficult to measure consistently, but I estimate that 2.6% of all WIA and 9.0% of medically evacuated WIA from the Iraq and Afghanistan theaters combined resulted in the major loss of a limb. Elevated non-hostile death rates (including deaths due to accidents, illnesses, homicides, or suicides) resulted in about 220 more deaths in Iraq and about 200 more deaths in Afghanistan than would have been expected in peacetime among populations of the size deployed to those two conflicts.     

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     

What is the global landpower network and what value might it provide?

US national security guidance, as well as the US Army’s operational experiences since 2001, emphasizes the importance of working closely with partner countries to achieve US strategic objectives. The US Army has introduced the global landpower network (GLN) concept as a means to integrate, sustain and advance the Army’s considerable ongoing efforts to meet US national security guidance. This study develops the GLN concept further, and addresses three questions. What benefits can the GLN provide the Army? What are the essential components of the GLN? What options exist for implementing the GLN concept? By developing the GLN concept, the Army has the opportunity to transition the GLN from an often ad hoc and reactive set of relationships to one that the Army more self-consciously prioritizes and leverages as a resource to meet US strategic objectives.     

Optimal sample size allocation for tests with multiple levels of stress with extreme value regression

In this article, we discuss the optimal allocation problem in a multiple stress levels life‐testing experiment when an extreme value regression model is used for statistical analysis. We derive the maximum likelihood estimators, the Fisher information, and the asymptotic variance–covariance matrix of the maximum likelihood estimators. Three optimality criteria are defined and the optimal allocation of units for two‐ and k‐stress level situations are determined. We demonstrate the efficiency of the optimal allocation of units in a multiple stress levels life‐testing experiment by using real experimental situations discussed earlier by McCool and Nelson and Meeker. Monte Carlo simulations are used to show that the optimality results hold for small sample sizes as well. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

India's Tortuous Road to Defence-Industrial Self-Reliance

…Rapid indigenisation is the cornerstone of our policy of self-reliance

India MoD Annual Report 1978–9