Risk assessment characteristic features

Two types of responses from exposure to hazardous substances, called stochastic or deterministic,5 are of concern in risk assessment. The two types of responses are distinguished by the characteristic features of the dose-response relationship, i.e., the relationship between the dose of a hazardous substance and the probability (or frequency) of a response. 

The EPA published a follow-up document (1998) that is much more extensive and detailed, and is beyond what can be published as an addendum. U.S. EPA (1998) also has a number of detailed discussions on various features of risk assessment. The importance of scale, the nonlinear characteristics of ecological systems, selection of assessment, and measurement endpoints are all important discussion items. 

Some issues arise. Risk assessment should consider all available information. Thus, a desirable characteristic of a conceptual framework would be to handle multiple sources of evidence. A nice feature offered by Monte Carlo simulation is that it is possible to account for correlations between input parameters. In its simplest form, these correlations are assigned assuming a pair-wise linear association between parameters. However, there are other ways to capture the correlation between parameters based on the same sources of evidence. Some sources of uncertainty are missed when parameters are predictions from other models. For example the link to the source of evidence is lost when not considering uncertainty in parameters that have been predicted by statistical regression models. 

Lifelines are in most cases spatially distributed systems. Therefore, seismic hazard should meet the specific features of each system considering also its spatial variability. The vulnerability analysis and risk assessment must be evaluated according to the precise typological characteristics of the components and networks, taking also into accormt the models used to describe vulnerability, usually in terms of fragility curves and relationships. Moreover, due to the spatial extent of utility and transportation networks, the seismic... 

ANN techniques would provide new insights into assessing and predicting the risks posed by ships with different characteristics. This will permit more rational comparison between alternative ship design and operational features. It is worth noting that ANNs can be a potential tool for risk assessment. 

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