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.

Using a theoretical model describing pulse shapes, we have clarified the relations between the observed pulses and their corresponding timescales, such as angular spreading time, dynamic time as well as cooling time. We find that the angular spreading timescale caused by curvature effect of fireball surface only contributes to the falling part of the observed pulses, while the dynamic one in th...

Due to the high-index contrast between the silicon core and silica cladding, the silicon waveguide allows strong optical confinement and large effective nonlinearity, which facilitates low cost chip scale demonstration of all-optical nonlinear functional devices at relatively low pump powers. One of the challenges in ultrafast science is the full characterization of optical pulses in real time....

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...

In the design of interlock loops for the signal exchange in machine protection systems, the choice of the hardware architecture impacts on machine safety and availability. The reliable performance of a machine stop (leaving the machine in a safe state) in case of an emergency, is an inherent requirement. The constraints in terms of machine availability on the other hand may differ from one faci...

Step-stress accelerated degradation test (SSADT) is a useful tool for assessing the lifetime distribution of highly reliable products (under a normal-use condition) when the available test items are very few. Recently, an optimal SSADT plan has been proposed in the literature which is based on the assumption that the underlying degradation path follows a Wiener process. However, the degradation...

In large-scale systems where number of components can approach a million a failure is a significant problem. In this paper authors have presented and analyzed failure data from different large systems. More than 100,000 disks with different interfaces which come from at least four different vendors have been investigated. According to information which one can find in datasheets the annual fail...