Many architecture–based software reliability models were proposed in the past. Regardless of the accuracy of these models, if a considerable uncertainty exists in the estimates of the operational profile and components reliabilities then a significant uncertainty exists in calculated software reliability. Therefore, the traditional way of estimating software reliability by plugging point estima...

Observed policy rates are smooth. Why should central banks smooth interest rates? We investigate if model uncertainty and parameters instability are a valid reason. We do so by implementing a novel ”thick recursive modelling” approach within the framework of small structural macroeconomic models. At each point in time we estimate all models generated by the combinations of a base-set of k obser...

−− This work presents a computational tool, useful in risk assessment of hazardous material releases. It is based on a methodology that takes into account the stochastic uncertainty of atmospheric parameters. This is relevant for calculating risk of hazardous gases, particulate matter or bioaerosols diffusion when an accidental release or continuous emission occurs. This methodology can be appl...

We analyze a quasi-chemical model for bacterial growth in the context of a parameter estimation problem using available experimental data sets. For many of the data sets the dynamics are simple and we show that the quasi-chemical model (QCM) is over parameterized in these cases. This results in larger uncertainty in the estimated parameters and is some cases instability in the inverse problem. ...

Uncertainty quantification (UQ) in eruption source parameters, like tephra volume, plume height, and umbrella cloud radius, is a challenge for volcano scientists because deposits are often sparsely sampled due to burial, erosion, related factors. We find that UQ improved by coupling an advection-diffusion model with two Bayesian inversion approaches: (a) robust but computationally expensive Gen...

Uncertainty in engineering analysis usually pertains to stochastic uncertainty, i.e., variance in product or process parameters characterized by probability (uncertainty in truth). Methods for calculating under stochastic uncertainty are well documented. It has been proposed by the authors that other forms of uncertainty exist in engineering design. Imprecision, or the concept of uncertainty in...

Most hydrologic/water quality (H/WQ) models that use rainfall as input assume spatial homogeneity of rainfall. Under this assumption this study assesses the variability induced in calibrated model parameters solely due to rainfall spatial variability. The AGNPS model and a network of 17 raingauges were used. Model parameters were estimated using rainfall observed at each gauge location, one at ...

The sensitivity of the seismic response parameters to the uncertain modeling variables of pile-founded fixed steel jacket platforms are investigated using the Tornado diagram and the first-order second-moment techniques. The effects of both aleatory and epistemic uncertainty on seismic response parameters have been investigated for an existing offshore platform. The sources of uncertainty consi...

As the use for regional seismic risk assessment increases, the need for reliable fragility curves for portfolios or classes of structures becomes more important. Fragility curves for portfolios of structures have the added complexity of having to deal with the uncertainty in geometric properties, along with the typical uncertainties such as material or component response parameters. Analysts ar...