Minimizing reductions in readiness caused by time-phased decreases in aircraft overhaul and repair activities

The Navy is often required to conduct personnel planning studies, A recent study on the assessment of effects of personnel reductions at the various aircraft Overhaul and Repair Activities (O & Rs) of the Bureau of Naval Weapons was carried out by one of the writers of the present paper. The methodology was systematic but relied on informal, judgmental decision procedures rather than on formal models incorporating optimization. Later study of the problem resulted in the approach described herein. The paper addresses this question: How can a personnel reduction in the Navy's aircraft O & Rs be distributed among activities with minimum reduction in readiness? A two-stage procedure involving linear programming models is developed. Solutions involve either extensions of aircraft overhaul cycles or a combination of such extensions with reductions in aircraft inventories.     

Programming the procurement of airlift and sealift forces: A linear programming model for analysis of the least-cost mix of strategic deployment systems

A linear programming model for analyzing the strategic deployment mix of airlift and sealift forces and prepositioning to accomplish the composite requirements of a set of possible contingencies is described in this paper. It solves for the least-cost mix of deployment means capable of meeting any one of a spectrum of contingencies, or meeting simultaneous contingencies. The model was developed by RAC as part of the U.S. Army's study program and has been used in analyses of deployment systems conducted in support of the U.S. Army, the Joint Chiefs of Staff and the Office of the Secretary of Defense. Results of analyses have influenced the preparation of long-range plans as well as the formulation of the FY67 Department of Defense budget. The paper gives the background and assumptions of the model, describes the model by means of a simple hypothetical example followed by a selected subset of a complete version, and discusses how the model is used.     

Attack and defense of ICBMs deceptively based in a number of identical areas

On-site verification of ICBMs in the context of an arms control agreement might involve a situation where an inspector would choose one or more of a number of identical areas to inspect and would have confidence that the other areas had the same characteristics. This article considers optimal attack and defense of missiles deceptively based in a number of identical areas. The attacker may allocate warheads across areas as he desires and uniformly within areas. The defender may allocate interceptors across areas as he desires and either uniformly or preferentially within areas. The effect of restricting the defender to uniform allocation across areas is explored for various assumptions. Robustness of surviving missiles with respect to the number of attacking warheads is studied. Results are presented for a wide range of cases.     

Crisis stability games

This article investigates the problem of crisis stability in the context of conventional and nuclear warfare, with emphasis on the incentives for one or both sides to engage in a preemptive nuclear strike. The approach is to offer two enriched versions of a recently developed model of escalation, to solve the models, and to observe that game-theoretic solutions can change from nonpreemption to preemption, depending upon the specific game structure and upon the values of the parameters describing the outcomes. © 1993 John Wiley & Sons, Inc.     

Robust preallocated preferential defense

The problem is to protect a set of T identical targets that may come under attack by A identical weapons. The targets are to be defended by D identical interceptors, which must be preallocated to defend selected targets. The attacker is aware of the number of interceptors, but is ignorant of their allocation. The size of the attack is chosen by the attacker from within a specified range. The robust strategies developed in this article do not require the defender to assume an attack size. Rather, the defender chooses a strategy which is good over a wide range of attack sizes, though not necessarily best for any particular attack size. The attacker, knowing that the defender is adopting a robust strategy, chooses the optimal attack strategy for the number of weapons he chooses to expend. The expected number of survivors is a function of the robust defense strategy and optimal attack strategy against this robust defense.     

The Royal Navy's Polaris lobby, 1955–62

This article examines the background to the Royal Navy's acquisition of Polaris. The conventional wisdom is that the Navy had little interest in Polaris, which was foisted on it upon the cancellation of Skybolt. Extensive use of files in the Public Record Office is made to mount the contrary argument, that the Admiralty had been interested in the submarine-launched ballistic missile since at least 1955, that there was widespread support for it among the Naval Staff, that a substantial amount of preparatory work was undertaken with the assistance of the US Navy, and that the naval staff were prepared to accept the deterrent role. Naval tactics – to play a waiting game and feign indifference – have contributed to the establishment of the orthodox interpretation, as has the view that the Navy was handicapped by the lack of a body of doctrine within which the deterrent role could be accommodated. The article shows that the orthodox account cannot be sustained by the evidence, which points to a naval triumph in terms of Whitehall politics and inter-service competition.     

Layered defense of deceptively based ICBMs

The basing of ICBMs is a fundamental problem of defense analysis. Deceptive basing and antiballistic missile defense are two of the methods available to attempt to insure that there are ICBMs surviving after undergoing an attack. This article treats tradeoffs among missiles, silos or shelters, exoatmospheric interceptors, and endoatmospheric interceptors. Most of the analysis deals with 200 missiles, the number of MX missiles which were recommended to be moved among the 4600 shelters of the Multiple Protective Shelter (MPS) deployment, though some variants in the number of missiles (from 115 to 400) are also treated here. The basic reference point of the analysis is the provision of 1000 ICBM warheads delivered in a second strike. The combination of exoatmospheric interceptors and endoatmospheric interceptors is referred to as “layered defense.” Warheads are destroyed by interceptors after the warheads separate from the missile which carries them. Exoatmospheric interceptors are assumed to achieve a non-nuclear kill, while endoatmospheric interceptors are assumed to achieve either a non-nuclear or nuclear kill, depending on the technology available to both sides. Exoatmospheric interceptors may be capable of protecting value targets against the warheads of a second strike. To the extent that this can be achieved, they facilitate a first strike with relative impunity and hence are destabilizing. This article explores various layered defense topics.     

Statistical decision analysis of stochastic linear programming problems

This paper presents a statistical decision analysis of a one-stage linear programming problem with deterministic constraints and stochastic criterion function. Procedures for obtaining numerical results are given which are applicable to any problem having this general form. We begin by stating the statistical decision problems to be considered, and then discuss the expected value of perfect information and the expected value of sample information. In obtaining these quantities, use is made of the distribution of the optimal value of the linear programming problem with stochastic criterion function, and so we discuss Monte Carlo and numerical integration procedures for estimating the mean of this distribution. The case in which the random criterion vector has a multivariate Normal distribution is discussed separately, and more detailed methods are offered. We discuss dual problems, including some relationships of this work with other work in probabilistic linear programming. An example is given in Appendix A showing application of the methods to a sample problem. In Appendix B we consider the accuracy of a procedure for approximating the expected value of information.     

Research and development on hypervelocity impact protection using Whipple shield: An overview

Whipple shield, a dual-wall system, as well as its improved structures, is widely applied to defend the hypervelocity impact of space debris (projectile). This paper reviews the studies about the mechanism and process of protection against hypervelocity impacts using Whipple shield. Ground-based experiment and numerical simulation for hypervelocity impact and protection are introduced briefly. Three steps of the Whipple shield protection are discussed in order, including the interaction between the projectile and bumper, the movement and diffusion of the debris cloud, and the interaction between the debris cloud and rear plate. Potential improvements of the protection performance focusing on these three steps are presented. Representative works in the last decade are mentioned specifically. Some prospects and suggestions for future studies are put forward.