Mean residual life of coherent systems consisting of multiple types of dependent components

Mean residual life is a useful dynamic characteristic to study reliability of a system. It has been widely considered in the literature not only for single unit systems but also for coherent systems. This article is concerned with the study of mean residual life for a coherent system that consists of multiple types of dependent components. In particular, the survival signature based generalized mixture representation is obtained for the survival function of a coherent system and it is used to evaluate the mean residual life function. Furthermore, two mean residual life functions under different conditional events on components’ lifetimes are also defined and studied.     

Simple paths with exact and forbidden lengths

We study new decision and optimization problems of finding a simple path between two given vertices in an arc weighted directed multigraph such that the path length is equal to a given number or it does not fall into the given forbidden intervals (gaps). A fairly complete computational complexity classification is provided and exact and approximation algorithms are suggested.     

Adjacency‐based local top‐down search method for finding maximal efficient faces in multiple objective linear programming

It is well‐known that the efficient set of a multiobjective linear programming (MOLP) problem can be represented as a union of the maximal efficient faces of the feasible region. In this paper, we propose a method for finding all maximal efficient faces for an MOLP. The new method is based on a condition that all efficient vertices (short for the efficient extreme points and rays) for the MOLP have been found and it relies on the adjacency, affine independence and convexity results of efficient sets. The method uses a local top‐down search strategy to determine maximal efficient faces incident to every efficient vertex for finding maximal efficient faces of an MOLP problem. To our knowledge, the proposed method is the first top‐down search method that uses the adjacency property of the efficient set to find all maximal efficient faces. We discuss this and other advantages and disadvantages of the algorithm. We also discuss some computational experience we have had with our computer code for implementing the algorithm. This computational experience involved solving several MOLP problems with the code.     

Deterrence Beyond Downunder: Australia and US Security Guarantees since 1955

ABSTRACT

From 1944 to 1973 Australia attempted to acquire atomic weaponry. This ambition was driven by the desire to contribute to defending British interests in Asia, fears of invasion by China, Indonesia, and Japan, great-power war, and the belief that nuclear weapons were merely bigger and better conventional weapons, that they would proliferate, and that US security assurances lacked credibility. Although the pursuit of the bomb was eventually abandoned, this was not the result of US assurances. Rather, geopolitical changes in Australia’s environment meant that a major attack on the continent was unlikely to occur outside the context of a confrontation between the US, China, and the Soviet Union. This article argues that Australia may soon have to rethink its policies towards US extended deterrence and instead focus on developing its own deterrent.     

Norms,Military Utility,and the Use/Non-use of Weapons: The Case of Anti-plant and Irritant Agents in the Vietnam War

The role of norms and military utility in the use of weapons is disputed by constructivist and realist scholars. Through an examination of US decision-making regarding anti-plant and irritant agents in the Vietnam War, I advance this debate in three key ways. First, I develop structural realism’s expectations regarding the role of military utility. Second, I demonstrate that social and material factors are at play in our understandings of both ‘norms’ and ‘military utility’, and that both played a role in US decisions. Third, I find that the dominant role – as structural realism expects – was played by military utility.     

Tipping the scales: short-term interventions and counterinsurgency

Particularly in African operations, United Nations (UN) peacekeeping forces have faced significant problems in restoring stability. In at least a few situations, unilateral national military interventions have been launched in the same countries. In the cases of Sierra Leone and Côte d’Ivoire, the British and French interventions respectively played a significant role in re-establishing stability. Lessons from these operations suggest that if effective coordination and liaison channels are established, such hybrid unilateral-UN missions can in fact be more successful than “pure” peace operations.     

Security sector reform,ethnic representation and perceptions of safety: evidence from Kosovo

This article explores the relationship between ethnic representation in security sector institutions and perceptions of safety. While most studies on post-conflict institutional reform focus on national institutions and outcomes, this article argues that a more nuanced view on ethnic representation is fruitful in order to account for the everyday perceptions of local people. Drawing on post-conflict Kosovo, the article analyzes how the representation of ethnic minorities in security institutions affects perceptions of safety among individuals across Kosovo’s municipalities. It also analyzes original interview data collected in the Pristina and Mitrovica municipalities that are typical cases of our sample. Both approaches validate that those municipalities that have ethnically representative security institutions also have higher levels of perceived safety.