Optimal arrangement of components via pairwise rearrangements

We introduce the notion of comparison of the criticality of two nodes in a coherent system, and devlop a monotonicity property of the reliability function under component pairwise rearrangement. We use this property to find the optimal component arrangement. Worked examples illustrate the methods proposed.     

The search for an intelligent evader: Strategies for searcher and evader in the two-region problem

This paper considers the search for an evader concealed in one of two regions, each of which is characterized by its detection probability. The single-sided problem, in which the searcher is told the probability of the evader being located in a particular region, has been examined previously. We shall be concerned with the double-sided problem in which the evader chooses this probability secretly, although he may not subsequently move: his optimal strategy consists of that probability distribution which maximizes the expected time to detection, while the searcher's optimal strategy is the sequence of searches which limits the evader to this expected time. It transpires for this problem that optimal strategies for both searcher and evader may generally be obtained to a surprisingly good degree of approximation by using the optimal strategies for the closely related (but far more easily solved) problem in which the evader is completely free to move between searches.     

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.     

Varieties of defection strategies from multinational military coalitions: Insights from operation Iraqi freedom

How do states defect from multinational military coalitions? The question deserves considerable academic scrutiny, as states increasingly rely on coalitions to prosecute military missions. Yet to the extent that coalition defection has been explored, the extant literature tends to see defection as a binary undertaking – states are either in or out. In practice, however, defection is an act of risk minimization in a manner that forces other coalition partners to fill resulting operational gaps. A coalition can therefore appear stable due to a constant number of flags associated with the mission, but in practice be much less coherent and capable. After defining defection as a non-routine abrogation of operational responsibility at other coalition partners’ expense, significantly prior to mission conclusion, this article explores several states’ participation in Operation Iraqi Freedom and the various manners by which they defected from that coalition. It concludes with implications for future scholarship.     

De-Constructing the French Wars: Napoleon as Anti-Strategist

The Emperor Napoleon I is regarded as one of the greatest generals of all time and, as such, he has attracted an immense bibliography. In spite of this, there have been few studies of him as a strategist: instead, it is simply assumed that it was enough for the Emperor to have conducted an operation for it to have had a logical strategic goal. In this article, however, Napoleon is shown to have been primarily an opportunist, who was frequently guided by the needs of the moment and swayed from his course by circumstance, while it is further suggested that, even considered on their own merits, many of his decisions were faulty in the extreme.     

The Determinants of Arms Production

This study analyzes the determinants of arms production in 15 countries using annual panel data from 1997 to 2002. The results suggest that real GDP per capita, military expenditures, arms exports, and arms imports are positively related to arms production.     

Dichotomous categorical variable formation in mathematical programming discriminant analysis models

Classification models, whether generated by statistical techniques or mathematical programming (MP) discriminant analysis methods, are often simplified by ad hoc formation of dichotomous categorical variables from the original variables with, for example, a dichotomous variable taking value 1 if the original variable is above a threshold level and 0 otherwise. In this paper an MP discriminant analysis method is developed for forming dichotomous categorical variables in problems with discriminant functions that are monotone in the original variables. For each of the original variables from which dichotomous variables may be formed, a set of possible threshold levels for dichotomous variable formation is defined. An MP model is then used to determine both the threshold level for forming each dichotomous variable and the associated discriminant function coefficient. The proposed MP approach is applied to a published problem and a number of simulated problem sets. It is shown that the discriminant functions in dichotomous categorical variables generated by this new MP approach can in some cases outperform the functions generated by standard MP discriminant analysis models using the original variables. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

Timing replacement decisions under discontinuous technological change

We consider the problem of deciding whether to keep a piece of equipment or replace it with a more advanced technology in an environment of technological change. Our model assumes that the costs associated with the presently available technology and future technologies are known, but that the appearance times of future technologies are uncertain. We develop a procedure for computing the optimal keep-or-replace decision that iteratively incorporates a technological forecast. For a certain class of situations, we show that our approach requires the minimum possible amount of forecasted data.     

Estimation of the survival function of a repairable standby series system

This article deals with the statistical analysis of an N-component series system supported by an active standby and one repair facility. Assuming that the life and repair times of the components are independent exponential random variables, the probability distribution of the first passage to the system failure time is shown to be a convolution of two independent exponential distributions. Three observation schemes are considered to obtain the maximum likelihood estimates of the survival function. Information matrices are supplied. Numerical results based on Monte Carlo simulation are presented. It is noted that component level information (failure rate, repair rate) is not necessary for estimating the survival function of the system.