The purpose of the paper is to describe and compare deterioration and maintenance models for civil infrastructures. These models can be applied to determine the best maintenance strategy to insure an adequate level of safety at minimal life-cycle cost while taking the uncertainties in the deterioration process into account. Without being complete, a time-dependent deterioration process can be m...

The paper presents a stochastic gamma process model to account for both sampling and temporal variability associated with a deterioration process that increases risk of failure of an aging structure. The proposed method is more versatile than the random-variable deterioration rate model commonly used in the structural reliability literature. The reason being that the random rate model cannot ca...

We consider the maintenance of a mission-based system that is designed to perform missions consisting of a random sequence of phases or stages with random durations. A …nite state Markov process describes the mission process. The age or deterioration process of the system is described by another …nite state Markov process whose generator depends on the phases of the mission. We discuss optimal ...

The time-dependent reliability analysis to model age-related deterioration is necessary to support strategic planning and optimization of civil engineering infrastructure systems. The paper presents a stochastic gamma process model to account for temporal variability associated with a deterioration process and its impact on the optimal age of replacement. The proposed method is more versatile t...

The deterioration law of the system will usually be assumed to be Markovian, that is, the future process of the system depends only on its state at the present time and not on its past history. This model has been suggested by Klein [1]. There are at least two good reasons for describing deterioration by a Markov model. Firstly, if each component is approximately subject to an exponential failu...

We describe the case of a right-handed patient who presented a severe acalculia in the context of a pure Gerstmann syndrome following a subangular lesion that spared the left inferior parietal lobule (IPL). The patient showed impairments in Arabic and verbal codes, in number production and comprehension, as well as in numerical facts and problem solving. By using the EC301 calculation battery, ...

This article argues that a significant shift is taking place in the sociological study of religion, and seeks to outline its main features. In order to do so it returns to Stephen Warner’s classic article of 1993 which drew a contrast between ‘old’ and ‘new’ paradigms in the sociology of religion. It develops Warner’s analysis by setting these paradigms in their European and American contexts r...