Five different algorithms for cooperation between assembly/packaging robots in a distributed system were developed and evaluated in simulation. Independent, autonomous operation of each robot was assumed. The goal was to maximize the number of assemblies while minimizing the standard deviation of the work between the different robots. Two of the algorithms, a fuzzy algorithm and a simple “take-...

This paper addresses the problem of scheduling non-preemptive moldable tasks to minimize the stretch of the tasks in an online non-clairvoyant setting. To the best of the authors’ knowledge, this problem has never been studied before. To tackle this problem, first the sequential sub-problem is studied through the lens of the approximation theory. An algorithm, called DASEDF, is proposed and, th...

The distributed system is a paradigm in which the components can communicate by means of the interface connected between them. The interaction between the components takes place in order to achieve a common goal. The reliability metrics is used to evaluate the performance of the components which is connected by the distributed systems. The Mean Time Between Failure (MTBF), Mean Time to Repair (...

Based on our current expectation for the exascale systems, composed of hundred of thousands of many-core nodes, the mean time between failures will become small, even under the most optimistic assumptions. One of the most scalable checkpoint restart techniques, the message logging approach, is the most challenged when the number of cores per node increases, due to the high overhead of saving th...

This paper presents the reliability and mean time to failure estimation of a deteriorating system that deteriorates with time. The system is two unit active parallel system where the units operates simultaneously. In this study maintenance is not allowed to the system. Laplace transforms is being utilize to solve the mathematical model developed. Expressions for reliability and Mean time to fai...

We analyze a periodically inspected system with hidden failures in which the rate of wear is modulated by a continuous-time Markov chain and additional damage is induced by a Poisson shock process. We derive explicitly the system’s lifetime distribution and mean time to failure, as well as the limiting average availability. The main results are illustrated through two numerical examples.

We assume a Boolean parallel system with exponentially distributed component failure times. In order to maximize the lifetime of the system we consider a repairman with Erlang-k distributed repair time. By extending the classical exponential case k = 1 to k ≥ 2 different repair semantics arise in this context. In the case of restart repair semantics we show that a repairman should have few Erla...

OBJECTIVES The aim was to study whether a workplace-registered frequent short-term sick leave spell pattern was an early indicator of future disability pension or future long-term sick leave among municipal eldercare workers. SETTING The municipal healthcare sector in the city of Aarhus, which is the second largest city in Denmark. PARTICIPANTS All elder care employees who worked the entire...

This paper presents a multi-objective optimisation model and algorithms for scheduling of radiotherapy treatments for categorised cancer patients. The model is developed considering real life radiotherapy treatment processes at Arden Cancer Centre, in the UK. The scheduling model considers various real life constraints, such as doctors’ rota, machine availability, patient’s category, waiting ti...

Tidal currents below the floating Ross Ice shelf are reconstructed by using a numerical tidal model. They are predominantly diurnal, achieve maximum strength in regions near where the ice shelf runs aground, and are significantly enhanced by topographic Rossby wave propagation along the ice front. A comparison with observations of the vertical motion of the ice shelf surface indicates that the ...