On the median residual lifetime and its aging properties: A characterization theorem and applications

This paper is devoted to study several aspects of the median residual life function (MERLF). In reliability studies, it is well known that, although the MERLF have several advantages over the mean residual life function (MRLF), the MRLF has the good property of uniquely determine a life distribution whereas either the median residual life function (MERLF) or an α‐percentile residual life do not have such good property. We shall give a characterization result where knowledge of both the MERLF and the survival function on an interval does uniquely determine the distribution. Moreover, in order to apply this characterization in practical situations, we propose a method to estimate the necessary information of the survival function. Relationships between analytical properties of the survival function and its associated MERLF are also obtained. Bryson and Siddiqui [J Am Statist Assoc 64 (1969), 1472–1483] proved relationships among seven criteria for aging, out of which two contained the MRLF (decreasing MRLF and net decreasing MRLF). In this paper, we prove that the same pattern of relationships holds if the MRLF is replaced by the MERLF. We also examine the aging criteria corresponding to an increasing MERLF and show that there is no relation between the behavior (increasing or decreasing) of the MERLF and of the MRLF. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005     

Offsets as industrial policy: Lessons from aerospace

Since 1975 “offsets” have begun to appear frequently in contracts covering international sales of aircraft and other products incorporating advanced technology. Offsets involve reciprocity beyond that normally found in an exchange of goods for money. They may involve co‐production or co‐design of the principal item to be exchanged, or acceptance by the seller of goods or services unrelated to it as partial payment (indirect offsets or countertrade).

The United States has become the major provider of offsets and anti‐offset sentiment has grown. Economists interpret them as trade diverting. Politicians from regions suffering loss of employment view them as bestowing unfair advantage to foreign competitors.

The authors examine offsets from both theoretical and policy perspectives and conclude that in such noncompetitive markets, second‐best considerations dominate, requiring case‐by‐case evaluation of impacts and rendering across‐the‐board determinations of welfare loss suspect.     

Adaptive forecasting of the size of a work force subject to random withdrawals

Adaptive forecasting procedures are developed for predicting the size of a work force which is subject to random withdrawals. The procedures are illustrated using Marine Corps data in which four stages of service for incoming cohorts are distinguished. Using these data, three forecasting procedures—conditional maximum likelihood estimation of prediction intervals; tolerance intervals; and Bayes prediction intervals—are compared.     

Multiple dispatches in a poisson process

An optimal policy is characterized for operating the following system. Customers arrive in [O, T] according to a homogeneous Poisson process. Instantaneous services are provided at times O and T. Additional instantaneous services can be provided at N intermediate stop ping times. These times must be chosen to minimize the total expected customer-hours in [O, T] spent waiting for service.     

Scheduling to minimize release-time resource consumption and tardiness penalties

We consider the problem of scheduling a set of jobs with a common due-date on a single-machine where the release time of a job is related to the amount of resource consumed. The objective is to minimize the total resource consumption and the total tardiness. While the problem is strongly NP-hard in general, we discuss two different special cases for which special properties are identified and used to develop efficient pseudo-polynomial time algorithms. © 1995 John Wiley & Sons, Inc.     

BOOK REVIEWS

This study examines how young people who have joined the South African National Defence Force (SANDF) on the two-year Military Skills Development System (MSDS) contract experience military service, and the effect this has on their ability to readapt to civilian life. The first part of the study examines the theoretical debates associated with military socialisation and reintegration into civilian life. Hereafter, the findings are presented in terms of the experiences of MSDS privates serving in the infantry, those that have left, and the perceptions of employment agencies in terms of the marketability of military skills. The conclusion is reached that MSDS members experience their two years in the SANDF as life-changing, that this affects their ability to reintegrate back into civilian society, and that the skills acquired during military training is of limited market value. The conclusion is reached that more needs to be done to assist these young military veterans to adapt to civilian life and to augment their military experience with more marketable skills to enable them to find gainful employment.     

Capacity and competence: full-spectrum counterinsurgency in the Horn of Africa

From 2006 to 2011, al Qaeda's East African proxy, al Shabaab, served as de facto ruling party of Somalia despite the efforts of the internationally recognized Transitional Federal Government (TFG). During these five years, a violent struggle between al Shabaab and the Burundian and Ugandan Peacekeepers of the African Union Mission in Somalia (AMISOM) resulted in thousands of dead civilians, hundreds of thousands of internally displaced persons, and a strategic environment inhospitable to reconciliation, recovery, or development. Beginning in August 2011, AMISOM was able to break the deadlock and force al Shabaab from Mogadishu, then subsequently, Kismayo, and ultimately to consolidate and reorganize in the Somali hinterland. In order to continue the momentum, the African Union and other partner nations must support the newly recognized Somali Federal Government (SFG), neutralize al Shabaab, and provide good governance to its constituents. Al Shabaab's revenue streams must be shut down and their offensive capability must be degraded while the strategic environment is shaped to ensure that conditions conducive to a revival do not exist. Failure to do so will likely see Somalia continuing to produce Islamic extremists and pirates to menace international maritime traffic in the Western Indian Ocean, destabilize East Africa, and adversely impact millions.