Asymptotic analysis of periodic policies for the inventory routing problem

In this article, a distribution system is studied where the sum of transportation and inventory costs is to be minimized. The inventory holding cost is assumed to be the same for all retailers. A fixed partition (FP) periodic policy is proposed with tight asymptotic worst‐case performance of 3/2 with respect to the best possible policy. This bound cannot be improved in the class of FP periodic policies. In partition‐based PB policies, the retailers are first partitioned into sets and then the sets are grouped in such a way that sets of retailers within a group are served together at selected times. A PB periodic, policy is presented with tight worst‐case asymptotic performance of with respect to the best possible policy. This latter performance improves the worst‐case asymptotic performance of of the previously best known policy for this problem. We also show that the proposed PB periodic policy has the best worst‐case asymptotic performance within the class of PB policies. Finally, practical heuristics inspired by the analyzed policies are designed and tested. The asymptotic worst–case performances of the heuristics are shown to be the same of those of the analyzed policies. Computational results show that the heuristics suggested are less than 6.4% on average from a lower bound on the optimal cost when 50 or more retailers are involved. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 00: 000–000, 2013     

The rules of engagement in Somalia – a judge advocate's primer 1

Scholars disagree on the prevailing focus on insurgent ideology. Some claim that the dominant Marxist ideology of the Cold War era has been supplanted by a new focus on ethnic and national identity. Others claim that many insurgencies were always focused on identity, but the Cold War and superpower antipathies distorted perceptions of insurgencies as politically-economically focused. Yet the heart of the matter is that analysts are not faced with an ‘either/or’ proposition.     

Book reviews

Frank Zimmer, Bismarcks Kampf gegen Kaiser Franz Joseph Konigsgratz und seine Folgen. Graz, Vienna, Cologne: Styria Verlag 1996. Pp.203,49 illus., 1 map. OS 350/DM 49. ISBN 3–222–12377–2.

Saul Zadka, Blood in Zion: How the Jewish Guerrillas drove the British out of Palestine. London and Washington: Brassey's, 1995. Pp.227, chron., illus., index. £19.95. ISBN 1–85753–136–1.

Theodore L. Gatchel, At the Water's Edge: Defending against the Modern Amphibious Assault. Annapolis, MD: Naval Institute Press, 1996. Pp.xvi+217, notes, biblio, index. $36.95. ISBN 1–55750–308–7.

Max G. Manwaring and William J. Olson (eds.) Managing Contemporary Conflict: Pillars of Success. Boulder, CO: Westview Press, 1996. Pp.269, no index. $65 (cloth); $25 (paper). ISBN 0–8133–8969 and 9978–5

Chris Seiple, The US Military/NGO Relationship in Humanitarian Interventions, Carlisle Barracks, PA: The

Richard L. Millett and Michael Gold‐Biss (eds.) Beyond Praetorianism: The Latin American Military in Transition. University of Miami: North/South Center Press; Boulder, CO: Lynne Rienner, 1996. Pp.xv +317, index. $24.95. ISBN 1–5745–000–9.

Rudolph C. Barnes Jr, Military Legitimacy: Might and Right in the New Millennium. London and Portland, OR: Frank Cass, 1996. Pp.199, select biblio., index. £27.50/$39.50, ISBN 0–714–4624–5.     

Book review

Steven L. Burg and Paul S. Shoup, The War in Bosnia‐Herzegovina: Ethnic Conflict and International Intervention.New York: M.E. Sharpe, 1999. Pp.xviii + 499, maps, tables, notes, biobliog., index. NP. ISBN 1–56324–308–3.     

Limiting behavior of the stochastic sequential assignment problem

The stochastic sequential assignment problem (SSAP) considers how to allocate available distinct workers to sequentially arriving tasks with stochastic parameters such that the expected total reward obtained from the sequential assignments is maximized. Implementing the optimal assignment policy for the SSAP involves calculating a new set of breakpoints upon the arrival of each task (i.e., for every time period), which is impractical for large‐scale problems. This article studies two problems that are concerned with obtaining stationary policies, which achieve the optimal expected reward per task as the number of tasks approaches infinity. The first problem considers independent and identically distributed (IID) tasks with a known distribution function, whereas in the second problem tasks are derived from r different unobservable distributions governed by an ergodic Markov chain. The convergence rate of the expected reward per task to the optimal value is also obtained for both problems. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

Inequality‐based reliability estimates for complex systems

Full‐system testing for large‐scale systems is often infeasible or very costly. Thus, when estimating system reliability, it is desirable to use a method that uses subsystem tests, which are often less expensive and more feasible. This article presents a method for bounding full‐system reliabilities based on subsystem tests and, if available, full‐system tests. The method does not require that subsystems be independent. It accounts for dependencies through the use of certain probability inequalities. The inequalities provide the basis for valid reliability calculations while not requiring independent subsystems or full‐system tests. The inequalities allow for test information on pairwise subsystem failure modes to be incorporated, thereby improving the bound on system reliability. We illustrate some of the properties of the estimates via an example application. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

Training US Army Peacekeepers

In Chechnya a protracted conflict only seemingly quieted down, but it still smolders and as the conflict is suppressed by coercion, it is inevitable that it will flare up at some time in the near future. The root causes of the conflict can be understood by use of globalization theory, which dialectically brings together the clashing forces from above and below. Civil society in Chechnya deteriorated, is politically curtailed, and has no resilience left. It thus results in a frozen conflict and an excluded and victimized society. Russian-style reconstruction does alleviate living conditions, but does not remediate the frozen conflict character of the present situation. The dynamics of the globalizing forces from below and above, summarized in the glocalization concept, not only explains the resistance by the Chechen people, for whom revolt, rebellion, and terrorism remain attractive options, but also serves as a model for other insurgencies. Reflecting on the two recent Chechen–Russian wars results in a paradigmatic case study.     

Urban Insurgency

Urban insurgency has generally been presented by analysts and security force personnel as a distinct variant. In contrast, insurgents themselves have often recognized the particular requirements of two dissimilar but related approaches of operation, the urban and rural. Hence they have sought to field approaches and doctrine that exploited the specifics of each. In some cases, simply debating such has led to internal fractures that could not be overcome. More often there has been a deadly rural-urban synthesis that has increasingly challenged security forces.