tires represent a critical spare part in mines. there is a shortage of medium and large tires. in addition, with increased mining activities and the creation of new mines, the demand for tires has increased significantly. thus, it is particularly important for mining engineers to identify tire characteristics and correctly manage the spare part inventory. spare parts management is critical from...

background: suicide is a problem worldwide and occupation is an important risk factor. in the last decade, 55 200 deaths in the us were attributed to occupational risk factors. objective: to determine if toxic metal exposure was associated with suicide risk among paducah gaseous diffusion plant (pgdp) workers. methods: we assembled a cohort of 6820 nuclear industry workers employed from 1952 to...

Choose the Cox proportional hazards regression model if the values in your dependent variable are duration observations. The advantage of the semi-parametric Cox proportional hazards model over fully parametric models such as the exponential or Weibull models is that it makes no assumptions about the shape of the baseline hazard. The model only requires the proportional hazards assumption that ...

Choose the Cox proportional hazards regression model if the values in your dependent variable are duration observations. The advantage of the semi-parametric Cox proportional hazards model over fully parametric models such as the exponential or Weibull models is that it makes no assumptions about the shape of the baseline hazard. The model only requires the proportional hazards assumption that ...

This paper puts a focus on the hazard function of inter-trade durations to characterize the intraday trading process. It sheds light on the time varying trade intensity and, thus, on the liquidity of an asset and the information channels which propagate price signals among asymmetrically informed market participants. We show, based on an exogenous information process, that the way traders aggre...

In this paper we develop mixed proportional hazard models in discrete time when there is cross sectional duration dependence because of the social interactions. To capture the cross sectional dependence, we use the lagged binary indicators of neighbors, which are weighted by the spatial weight matrix. We investigate the nonparametric specification for the baseline hazard and the unobserved hete...

Lagged Duration Dependence in Mixed Proportional Hazard Models We study the non-parametric identification of a mixed proportional hazard model with lagged duration dependence when data provide multiple outcomes per individual or stratum. We show that the information conveyed by the within strata variation can be exploited to nonparametrically identify lagged duration dependence in more general ...

The component’s reliability is a function of component age during a system’s operating life. Component aging is strongly affected by maintenance activities performed on the system.Two categories of maintenance activities are considered in this work: Corrective maintenance (CM) and preventive maintenance (PM). We expound a new method to integrate the effect of CM while planning for the preventiv...