El próximo viernes 31 de enero a las 12:00 en el Salón de Grados de la Facultad de Ciencias del Deporte en Cáceres, el profesor Nicola Esposito de la Universitá degli Studi di Napoli Federico II impartirá la conferencia titulada «An adaptive maintenance policy for degrading units in the presence of random effect and measurement error» dentro del Colloquium del Departamento.

Resumen: This talk presents an adaptive condition/based maintenance policy for degrading units which operate in the joint presence of temporal variability, unit‑to‑unit variability, and measurement error. The temporal variability is described by using a gamma process. The unit-to-unit variability is accounted for by incorporating a random effect into the basic model. The presence of measurement error is modeled by using two alternative perturbing terms. The link between degradation and reliability is established by assuming that a unit fails when its degradation level passes a given threshold.
The proposed maintenance policy is developed for experimental situations where, due to inspection costs, the state of each unit can be measured only at one inspection epoch, over the course of its operating life. More specifically, it is assumed that, at a predetermined inspection time, an imperfect inspection is firstly carried out. Hence, based on the result of this inspection it is decided whether to immediately replace the unit, to postpone its replacement to a future time, or to carry out an additional perfect inspection. The result of the perfect inspection, when it is performed, is used again to decide whether to immediately replace the unit or to postpone its replacement to a future time. The postponement time is determined by using a measurements‑based decision rule, which allows to adaptively select its optimal unit‑specific value. Postponed replacements are always made without performing other inspections.
Two comparative studies demonstrate the utility of the proposed policy and show how its use allows to decide whether performing the considered inspections is convenient or not, depending on inspection costs and on the features of the degradation process. The comparative studies are developed by applying the policy to a real‑world inspired case of a buried pipeline.