Inference on a future reliability parameter with the weibull process model

An inferential procedure is presented which provides confidence intervals for a future reliability parameter when reliability growth testing is only partially completed. Hypothesis tests based on this method are uniformly most powerful unbiased. These results are applicable if (1) the system failure rate can be modeled as the intensity function of a Weibull process and (2) efforts to improve reliability are assumed to continue at a steady rate throughout the intervening period of testing. The usefulness of this methodology is illustrated by evaluating the risk of not reaching some future reliability milestone. If such risk is unacceptably high, program management may have time to identify problem areas and take corrective action before testing has ended. As a consequence, a more reliable system may be developed without incurring overruns in the scheduling or cost of the development program.     

Graveyard of Analogies: The Use and Abuse of History for the War in Afghanistan

Decades of scholarship have warned against using historical analogies for policymaking. But the Taliban insurgency appears, on the surface, to confirm the usefulness of historical analogies to the British and Soviet wars in Afghanistan. I review the use of analogies for the war in Afghanistan and argue the analogies were historically unsound and strategically unhelpful. In fact, their effect on policy helped create the conditions for the very insurgency policymakers most hoped to avoid. The Taliban insurgency did not occur because of the presence of too many foreign troops and aid workers, but because there were too few.     

NUCLEAR ATTRIBUTION AS DETERRENCE

Recently, post-explosion nuclear forensics, or nuclear attribution, has gained a new spotlight within the nuclear weapons scientific and policymaking community. Academics are beginning to ask whether post-explosion forensics might create a replacement for an international nonproliferation regime, or at least offer a fallback option to deter states and individuals from selling nuclear materials. This paper examines current attribution technology from unclassified literature and finds the technology to be well developed but not foolproof, such that nuclear attribution currently provides little deterrent value. If current capabilities were publicized more thoroughly and if the post-explosion process of assessing the evidence were internationalized, states and intermediate actors might be deterred more effectively. Developing a nuclear fingerprint database is also discussed. While useful, its impact on deterrence would be minimal.     

BUSTING OUT

This report explores Iranian popular opinion on the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the determinants of Iranian attitudes. Using data from a 2008 survey of 710 Iranians administered by the University of Maryland's Program on International Policy Attitudes, we find that that a significant minority of Iranians (10 percent in 2006 and 14 percent in 2008) would prefer that Iran withdraw from the NPT. Our statistical analysis shows that Iranians who fear a US attack on Iranian nuclear facilities and distrust the International Atomic Energy Agency are more likely to want to quit the NPT. We therefore argue that those who do not trust other nations are most likely to oppose the NPT.     

Book Reviews

National Security Concepts of States: New Zealand. By Kennedy Graham. Taylor & Francis, London (1989), ISBN 0-8448-1614-0, £27.00

Power and Prestige in the British Army. By R.G. L. von Zugbach. Gower, Aldershot (1988), ISBN 0-566-05561-9, £22.50

The American Civil War and the Origins of Modern Warfare—Ideas, Organization, and Field Command. By Edward Hagerman. Indiana University Press, Bloomington, IN (1988), ISBN 0-253-30546-2, $37.50 (£23.29)

British Seapower and Procurement between the Wars: a Reappraisal of Rearmament. By G. A. H. Gordon. Macmillan, London (1988), ISBN 0-333-42332-1. £29.50

Armies in Low-intensity Conflict: a Comparative Analysis. Edited by David A. Charters and Maurice Tugwell. Brassey's Defence Publishers, London (1989), ISBN 0-08-036253-2, £25.00 ($45.00); Deadly Paradigms: the Failure of U.S. Counterinsurgency Policy. By Michael Shafer, Leicester University Press, Leicester (1988), ISBN 0-7185-1311-8, £28.00

British Defence Policy Striking the Right Balance. By J. Baylis. Macmillan, London (1989), ISBN 0-333-49133-5, £29.50 or £9.99     

The distribution of recoverable inventory items from a repair center when the number of consumption centers is large

This paper considers real-time decision rules for an inventory system where items are repaired than “used up.” The problem is to decide which user in the system has the greatest need for the newly available inventory items coming out of repair. The main result shows that two published approahes, the Transportation Time Look Ahead policy and METRIC, are optimal when the number of users gets large. A useful byproduct of the proof is a lower bound on the average backorder rate for a repair-inventory system of any size.