On some stochastic inequalities involving minimum of random variables

Let X_i be independent IFR random variables and let Y_i be independent exponential random variables such that E[X_i]=E[Y_i] for all i=1, 2, ? n. Then it is well known that E[min (X_i)] ≥E[min (X_i)]. Nevertheless, for 1≤i≤n exponentially distributed X_i's and for a decreasing convex function ?(.). it is shown that .     

Security assurances and proliferation risks in the Trump administration

Comments that Donald Trump made while campaigning to be U.S. president have raised concerns that his administration will pull back from U.S. alliance commitments and encourage countries such as Japan and South Korea to acquire nuclear arms. The new article by Frühling and O’Neil outlines an institutional framework that can be helpful in assessing the risks that Trump administration policies will lead to nuclear proliferation. An institutional perspective shows that important elements of U.S. security assurances will continue to function, and this reduces the chances that President Trump’s actions or statements will trigger proliferation by U.S. allies. The greatest risk to global non-proliferation efforts posed by a Trump administration in fact lies elsewhere, in the possibility that President Trump will seek to abrogate the Iran nuclear deal.     

The nuclear education of Donald J. Trump

During the 2016 American presidential campaign, Democrats and Republicans alike repeatedly raised concerns at the prospect of Donald Trump being in charge of America’s nuclear arsenal based on his seemingly unstable personality. Unfortunately, this emphasis on Trump’s character distracted attention from any in-depth investigation into his long-standing interest in nuclear issues. This article seeks to remedy this shortcoming by highlighting the nuclear legacy Trump will inherit from Obama, surveying his statements on nuclear issues over more than three decades, and providing an analysis of constraining factors on his administration’s nuclear agenda, particularly domestic institutions. It finds that most of Trump’s views on nuclear issues are relatively consistent with past Republican presidents. Where he is unique, however, is in his use of social media, which has potential implications on nuclear signaling.     

The US NATO and military burden sharing: post-Cold War accomplishments and future prospects

NATO burden sharing has become an especially timely issue in the past several years as a result of a number of factors, including Russian annexation of Crimea and destabilization of eastern Ukraine in 2014. This article argues that alliance unity among the great democracies of Europe and North America is indispensable to peace and stability on the Eurasian continent. A fractured NATO, and especially, a large divide in purposes or commitments as between the United States and its European security partners, invites aggression and the possibility of inadvertent escalation. Past successes and failures in US-involved multinational peace and stability operations, within and outside of Europe, show that mission accomplishment requires give and take, including the occasional acceptance of unequal costs and benefits among the members, in order to achieve peace and security objectives.     

Cost allocation and communication

This article considers a special class of cost allocation problems, where the communication possibilities among the agents are restricted. Integral formulas are derived for two allocation rules: The Myerson value and the position value. © 1993 John Wiley & Sons, Inc.     

The poverty of power in military power: how collective power could benefit strategic studies

Strategic studies deals intimately with the topic of power. Most scholars in the discipline work with a concept of power as an adversarial zero-sum competition. This is natural and necessary. However, other conceptions of power developed within political science and sociology could enrich strategic studies. Approaching two typical, traditional tasks of strategy – alliance building and war-fighting – this article demonstrates the heuristic mileage of theories of collective power. In particular, we can shed new light on the post-Cold War transformation of NATO as well as state-building as a strategy in counter-insurgencies with new ideas of power. Broadening the palette of theories of power is thus valuable if strategic studies is to prosper as an independent field of study.     

Maintaining systems with heterogeneous spare parts

We consider the problem of optimally maintaining a stochastically degrading, single‐unit system using heterogeneous spares of varying quality. The system's failures are unannounced; therefore, it is inspected periodically to determine its status (functioning or failed). The system continues in operation until it is either preventively or correctively maintained. The available maintenance options include perfect repair, which restores the system to an as‐good‐as‐new condition, and replacement with a randomly selected unit from the supply of heterogeneous spares. The objective is to minimize the total expected discounted maintenance costs over an infinite time horizon. We formulate the problem using a mixed observability Markov decision process (MOMDP) model in which the system's age is observable but its quality must be inferred. We show, under suitable conditions, the monotonicity of the optimal value function in the belief about the system quality and establish conditions under which finite preventive maintenance thresholds exist. A detailed computational study reveals that the optimal policy encourages exploration when the system's quality is uncertain; the policy is more exploitive when the quality is highly certain. The study also demonstrates that substantial cost savings are achieved by utilizing our MOMDP‐based method as compared to more naïve methods of accounting for heterogeneous spares.     

Modeling the performance of a scanning radio communications sensor

A model which allows the prediction of long-term average report rates against an array of radio emitters by a scanning sensor is presented. The model is based on Markov renewal theory.