Models and measures to evaluate the effectiveness of funds utilization for scientific research and development of advanced technologies

The purpose of this report was to construct some alternative methods to estimate the effectiveness of investments in scientific research and development of advanced technologies, especially their long-term effects. The Study Group decided to focus on the sub-problem of finding the relation between the spending on science and the quality of science itself. As a result, we have developed two independent methodologies. The most promising one is based on the theory of time-delay systems, which allows capturing effects of the time-lag between the use of funds and the results related to scientific work. Moreover, the methodology gives an opportunity to seek the optimal spending scenario that would fulfill some prescribed constraints (e.g. it would minimize costs and at the same time remain above a desired level of quality of science). The second methodology is premised on Stochastic Frontier Analysis and it can be applied to determine the form of relation between the amount of financing and the results of scientific work. It offers considerable advantages for analyses of several forms of relation at once (production functions) and for a suitable choice of the best one. Both methods are promising, however, additional work is necessary to apply them successfully to some real-life problems

Optimal maintenance strategies for systems with partial repair options and without assuming bounded costs

We study a repairable system with Markovian deterioration and partial repair options, carried out at fixed times $n=1,2,\ldots$ and look for optimal strategies under certain conditions. Two optimality criteria are considered: expected discounted cost and long-run average cost. Douer and Yechiali found conditions under which a policy in the class of generalized control limit policies is optimal. In this paper conditions are found under which an optimal policy is a control-limit policy. We explicitly explain how to derive this optimal policy; numerical examples are given, too

Does Hydration Impact Memory: A Systematic Review

With 60% of the adult human body composed of water it makes sense that maintaining proper hydration levels is important to survival as well as living a healthy life. Water has many roles throughout the human body: thermoregulation, being a carrier, being a lubricant, and acting as a reaction medium. As a carrier, water is responsible for allowing exchanges between cells, interstitial fluid and capillaries. In addition, water regulates the blood volume and allows blood circulation. Since water is responsible for these tasks, many systems in the body as well as the brain are reliant upon proper hydration levels to function properly

Integrated production quality and condition-based maintenance optimisation for a stochastically deteriorating manufacturing system

This paper investigates the problem of optimally integrating production quality and condition-based maintenance in a stochastically deteriorating single- product, single-machine production system. Inspections are periodically performed on the system to assess its actual degradation status. The system is considered to be in ‘fail mode’ whenever its degradation level exceeds a predetermined threshold. The proportion of non-conforming items, those that are produced during the time interval where the degradation is beyond the specification threshold, are replaced either via overtime production or spot market purchases. To optimise preventive maintenance costs and at the same time reduce production of non-conforming items, the degradation of the system must be optimally monitored so that preventive maintenance is carried out at appropriate time intervals. In this paper, an integrated optimisation model is developed to determine the optimal inspection cycle and the degradation threshold level, beyond which preventive maintenance should be carried out, while minimising the sum of inspection and maintenance costs, in addition to the production of non-conforming items and inventory costs. An expression for the total expected cost rate over an infinite time horizon is developed and solution method for the resulting model is discussed. Numerical experiments are provided to illustrate the proposed approach