Minimizing costs of sequential and parallel personnel testing programs

We consider groups of tests for personnel selection purposes in which each test has a known a priori probability of being failed, such failure resulting in outright rejection and termination of testing. Each test has a fixed cost and given duration. We consider the minimization of the total expected cost due to both the fixed costs and the delay costs when the tests may be conducted sequentially or in parallel. In the latter situation, a heuristic algorithm is proposed and illustrated.     

Analysis of the turbulent regime of the progress curve when new learning additions have variable slopes

Learning curves have been used extensively for predictive purposes in the airframe and other industries. In many instances this has led to erroneous results because analysts failed to extend learning curve theory and develop adequate analytical techniques in the turbulent regime of the cost history characterizing these industries. It is this area where a series of design changes induces a series of perturbations whose turbulence intensity is a function of the frequency of occurrence and magnitudes of the design changes under consideration. In Ref. 1, a series of formulations amenable to machine programming was developed for the accurate determination of perturbed unit costs. This development was based on additions of new learning having a constant slope. In this discussion, the development of Ref. 1 will be generalized by developing formulas for the addition of new effort having variable slopes. Consideration will also be given to the expressions involving elementary unit cost expressions so that cumulative average and cumulative total values can readily be obtained from existing experience curve tables. Conversely, the problem of determining the magnitudes of design changes and the slopes of new effort from graphical data will also be considered.     

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.     

NATO’s push into the Caucasus: geopolitical flashpoints and limits for expansion

The Caucasus has been a major flashpoint of contention between NATO and a resurgent Russia since the collapse of the Soviet Union. The rivalry saw the escalation of hostility in the region during the brief 2008 Russo-Georgian War where a NATO-backed Georgia challenged South Ossetia supported by the Russian military. In 2011, NATO officially recognised Georgia as a potential member, challenging Russia’s traditional sphere of influence in the Caucasus. Moscow says the Eastward expansion of NATO into the Baltics and to include Georgia as a member state is a method of containing a resurgent Russia. However, the former Soviet Republics of Ukraine, the Baltics and Georgia, maintain that Russia represents a threat to their sovereignty, as seen by the Russian support of the breakaway unrecognised Republics of South Ossetia and Abkhazia. A hostile rivalry between the Russian-backed Armenia and Azerbaijan, which is reliant upon NATO-member Turkey, intensifies the polarisation in the Caucasus.