An extreme-point approach for obtaining weighted ratings in qualitative multicriteria decision making

Many attempts have been made in the past to obtain estimates for the weights and ratings values of a multicriteria linear utility function. In particular, the problem arises when both criteria importance and alternatives' ratings are expressed in a qualitative ordinal manner. This article proposes an extreme-point approach for obtaining the overall ratings in the presence of ordinal preferences both for the criteria importance and the alternatives' rankings. In particular it is shown that Borda's method of scores is obtained as a special case. © 1996 John Wiley & Sons, Inc.     

A suboptimality bound for permutation policies in single machine stochastic scheduling

A general class of single machine stochastic scheduling problems incorporating precedence constraints is modelled as a family of competing Markov decision processes. A bound on the optimal return yields a suboptimality bound for permutation policies. This in turn leads to a generalised “used better than new” principle as a (highly intuitive) sufficient condition for the optimality of a permutation policy in the class of all (preemptive) policies. © 1995 John Wiley & Sons, Inc.     

How Is a Man to Decide? Unjust Combatants,Duress and McMahan’s Killing in War

Jeff McMahan’s much-discussed work Killing in War is an important part of the revisionist school of just war studies. This paper avoids discussion of McMahan’s use of human rights and examines the practical consequences of his argument about duress on soldiers to fight an unjust war. These arguments are found to be wanting and to be impractical ones that do not fit battlefield realities. The importance of the Law of Armed Conflict and the legal equality of combatants that is part of it is emphasised and accepted as the most practical way of regulating battlefield behaviour and saving lives. It is concluded that attempts to tell soldiers what to do when they may be fighting an unjust war add to their burdens and are misplaced.     

Aircraft sortie effectiveness model

A mathematical model describing the sortie of a single aircraft under enemy threats, attacking a single passive target, is developed. Emphasis is placed on the determination of the probabilities associated with the various events in the sortie. These probabilities are then used to derive appropriate measures of effectiveness. The optimum sortie time is analyzed.     

Beyond the Double Game: Lessons from Pakistan’s Approach to Islamist Militancy

States commonly take one of three approaches to militant groups on their soil: collaboration; benign neglect; or belligerence. All three approaches are present in Pakistan, where some groups also move back and forth among these categories. I employ the term “coopetition” to capture this fluidity. The dynamic nature of militancy in Pakistan makes the country an excellent laboratory for exploring a state’s assessment of the utility an Islamist militant group offers, and the threat it poses relative to other threats informs the state’s treatment of that group. In this article, I put forward a typology that situates Islamist militants in Pakistan in one of the above four categories. I also illustrate how a group’s identity, objectives, and alliances inform assessments of its utility and threat relative to other threats. In addition to enhancing our understanding of militant–state dynamics, this taxonomy builds on and helps to unify earlier typologies of Pakistani militancy.     

Saddam versus the inspectors: the impact of regime security on the verification of Iraq’s WMD disarmament

The discovery that Iraq had no weapons of mass destruction (WMD) in 2003 raised the question of why Saddam had prevented UN weapons inspectors from fully accounting for his disarmament. The leading explanation for Saddam’s behavior is that he valued ambiguity as part of a strategy of ‘deterrence by doubt’. This article argues that Iraq’s obstruction of inspectors in the late 1990s was motivated by his desire to shield Iraq’s regime security apparatus from UNSCOM’s intrusive counter-concealment inspections. The failure to understand how strongly Saddam’s concerns about his personal safety drove Iraq’s contentious relationship with UNSCOM set the stage for the invasion of Iraq in 2003.     

What explains the failure of U.S. army reconstruction in Afghanistan?

ABSTRACT

This author wrote his doctorate thesis on post-conflict army reconstruction, submitting it in 2011. Continued research on the subject in the intervening seven years indicates that his theoretical propositions can be refined and improved. This article examines refinements to the model, and then applies those refinements in detail to the Afghan case. In so doing, it shifts the focus from potentially altruistic state-building to a case that was driven by pure national-strategic interests. Issues surrounding the liberal peace ideology dominate recent army reconstruction in conflict-affected states. The liberal peace underpinning is of supreme importance, so much so that in many discussions, it is internalised and accepted virtually without thought. This paper will advance the body of knowledge by establishing, for the first time, a theoretical basis for the widespread failure of army reconstruction in Afghanistan. The empirical basis builds on extensive previous research by other scholars. The resulting model can also be applied to better explain outcomes in other similar cases.     

Estimating a survival curve when new is better than used with respect to a distinguished set

Hollander, Park, and Proschan define a survival function S of a positive random variable X to be new better than used at age t₀ (NBU-{t₀}) if S satisfies $ \begin{array}{*{20}c} {\frac{{S(x + t_0)}}{{S\left({t_0} \right)}} \le S\left(x \right),} & {{\rm for}\,{\rm all}\,x\, \ge \,0,} \\ \end{array}$ where S(x) = P(X > x). The NBU-{t₀} class is a special case of the NBU-A family of survival distributions, where A is a subset of [0, ∞). These families introduce a variety of modeling possibilities for use in reliability studies. We treat problems of nonparametric estimation of survival functions from these classes by estimators which are themselves members of the classes of interest. For a number of such classes, a recursive estimation technique is shown to produce closed-form estimators which are strongly consistent and converge to the true survival distribution at optimal rates. For other classes, additional assumptions are required to guarantee the consistency of recursive estimators. As an example of the latter case, we demonstrate the consistency of a recursive estimator for S ∈ NBU-[t₀, ∞) based on lifetime data from items surviving a preliminary “burn-in” test. The relative precision of the empirical survival curve and several recursive estimators of S are investigated via simulation; the results provide support for the claim that recursive estimators are superior to the empirical survival curve in restricted nonparametric estimation problems of the type studied here.     

Scheduling of parallel processors: A posterior bound on LPT sequencing and a two-step algorithm

This article considers the problem of scheduling parallel processors to minimize the makespan. The article makes two key contributions: (1) It develops a new lower bound on the makespan for an optimal schedule, and (2) it proposes an efficient two-step algorithm to find schedules of any desired accuracy, or percent above optimal. In addition, a posterior bound on LPT (longest processing time) sequencing is developed in the article. It is proved that this bound dominates the previously reported bounds on LPT sequencing.     

Estimation of the survival function of a repairable standby series system

This article deals with the statistical analysis of an N-component series system supported by an active standby and one repair facility. Assuming that the life and repair times of the components are independent exponential random variables, the probability distribution of the first passage to the system failure time is shown to be a convolution of two independent exponential distributions. Three observation schemes are considered to obtain the maximum likelihood estimates of the survival function. Information matrices are supplied. Numerical results based on Monte Carlo simulation are presented. It is noted that component level information (failure rate, repair rate) is not necessary for estimating the survival function of the system.