PURPOSE Competing risks observations, in which patients are subject to a number of potential failure events, are a feature of most clinical cancer studies. With competing risks, several modeling approaches are available to evaluate the relationship of covariates to cause-specific failures. We discuss the use and interpretation of commonly used competing risks regression models. EXPERIMENTAL D...

The authors conducted a simulation study to evaluate whether exclusion of the early mortality (deaths occurring during a prespecified period immediately after baseline) reduces confounding of the exposuremortality relation by preexisting disease. The simulation specified an exposure that decreased mortality risk in the absence of confounding and then introduced confounding by preexisting diseas...

premixed combustion is widely used for reducing pollutant emission from combustion chambers. however, these systems may be sensitive to complex phenomena such as flashback. in the present study flame, flashback and structure of premixed laminar flames are investigated theoretically. the mathematical model includes the axi-symmetric continuity, navier stocks, energy, and species equations. combu...

in this research an algorithm based on monte carlo simulation is introduced to assess the risk of fire following earthquake in residential, industrial, educational, and governmental land-uses in district no. 20 of tehran. the proposed algorithm consist of different modules including hazard analysis, vulnerability assessment, leak and break analysis of damaged pipeline, ignition probability anal...

background and objective: prevention of accidents—a crucial requirement in oil industries—involves hazard recognition, risk assessment, and corrective actions. the purpose of this study was to compare the etba and hazop techniques for risk assessment in a gasoline refinery unit. methods: in this case study, data were collected using process flow diagram, walking–talking through method, piping a...