An algorithm for a class of loading problems

The loading problem we consinder is to assign a set of discrete objects, each having a weight, to a set of boxes, each of which has a capacity limit, in such a way that every object is assigned to a box and the number of boxes used is minimized. A characterization of the assignments is offered and used to develop a set of rules for generating nonredundant assignments. The rules are incorporated into an implicit enumeration algorithm. The algorithm is tested against a very good heuristic. Computational experience shows that the algorithm is highly efficient, solving problems of up to 3600 0-1 variables in a CPU second.     

An algorithm for 0-1 multiple-knapsack problems

The 0-1 multiple-knapsack problem is an extension of the well-known 0-1 knapsack problem. It is a problem of assigning m objects, each having a value and a weight, to n knapsacks in such a way that the total weight in each knapsack is less than its capacity limit and the total value in the knapsacks is maximized. A branch-and-bound algorithm for solving the problem is developed and tested. Branching rules that avoid the search of redundant partial solutions are used in the algorithm. Various bounding techniques, including Lagrangean and surrogate relaxations, are investigated and compared.     

Markov chain with taboo states and reliability

A computationally feasible matrix method is presented to find the first-passage probabilities in a Markov chain where a set of states is taboo during transit. This concept has been used to evaluate the reliability of a system whose changes in strength can be thought of as a Markov chain, while the environment in which it is functioning generates stresses which can also be envisaged as another Markov chain.     

Statistical tests for exponential service from m/g/1 waiting-time data

From an original motivation in quantitative inventory modeling, we develop methods for testing the hypothesis that the service times of an M/G/1 queue are exponentially distributed, given a sequence of observations of customer line and/or system waits. The approaches are mostly extensions of the well-known exponential goodness-of-fit test popularized by Gnedenko, which results from the observation that the sum of a random exponential sample is Erlang distributed and thus that the quotient of two independent exponential sample means is F distributed.     

The many-product cargo loading problem

An algorithm, based upon dynamic programming, is developed for a class of fixed-cost cargo loading problems. The problems can be formulated as integer programming problems, but cannot be efficiently solved as such because of computational difficulties. The algorithm developed has proved to be very efficient in an actual operations research study involving over 500 different cargo items, more than 40 possible stops and several types of transportation vehicles. A numerical illustration is provided.     

Use of completely reduced matrices in solving transportation problems with fixed charges

This paper shows how completely reduced matrices can be used in obtaining exact or approximate solutions to transportation problems with fixed charges. It does not treat methods for obtaining reduced matrices, which are available elsewhere, but it does discuss the problem of obtaining a completely reduced matrix, and then a general parametric solution to the primal problem, from any particular solution. Methods for obtaining particular solutions with determinacies of maximum order (solutions for the constant fixed charges problem) are then presented. The paper terminates with a discussion of methods which are useful in obtaining approximations to solutions of fixed charges problems with charges not constant.     

The Taliban’s Islamic Emirate of Afghanistan (1996–2001): ‘War-Making and State-Making’ as an Insurgency Strategy

This paper examines the institutional and functional aspects of the Taliban’s Islamic Emirate of Afghanistan (IEA). The Taliban’s coercive approach and its entire reliance on “war-making” to “state-making” shows the difficulty of the transformation of an insurgent group into a state structure. The Taliban was primarily capable of establishing a two-track system of governance. However, the assessment of the IEA’s institutional and functional capabilities shows that the military–political organization formed by the Taliban lacked statehood in all three areas of legitimacy, authority and capacity.     

Comparable deterrence – target,criteria and purpose

The last decade has seen several advances in the study of deterrence. These advances have sparked some strong disagreements regarding interpretation of the models and what their contributions signify. This paper appraises the discussions from a model theoretic perspective. It is argued that when comparing rivalling models three aspects; (i) target, (ii) criteria and (iii) type of purpose should be taken into account in order to make a proper appraisal. Informed by these aspects it is evident that the three deterrence models analysed address different aspects, in different ways and to different ends. From this perspective, the so-called Perfect Deterrence model must be recognised as a clear advancement in the research field. Model comparison will always be context relative and a plurality of models should be viewed favourably.