Skip to main content

Assessing the Reliability of Complex Models Mathematical and Statistical Foundations of Verification, Validation, and Uncertainty Quantification (2012) / Chapter Skim
Currently Skimming:

6 Making Decisions
Pages 86-94

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 86...
... As such, VVUQ activities are part of a larger group of decision-support tools that include modeling, simulation, and experimentation. The role of VVUQ could be as simple as providing uncertainty bounds or a worst-case analysis for a particular risk metric, or it could be as complex as using more rigorous methods (such as the design of validation experiments or other applications requiring optimization under uncertainty)
Read the entire page →
From page 87...
... Decision makers must allocate resources throughout the VVUQ process, keeping in mind the goal of the study. For example, decision makers must weigh the relative benefit of investing in improvements to the fidelity of a given physics model against the benefit of conducting relevant physical experiments for calibration.
Read the entire page →
From page 88...
... Strategic Command each write a letter to 1 Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Read the entire page →
From page 89...
... QMU provides a framework for systematically including the results of modeling and simulation, ongoing nonnuclear experiments, legacy nuclear testing, and informed judgment from nuclear weapons design physicists. A summary of the QMU methodology and current state of practice can be found in a study conducted by the National Research Council (NRC, 2009)
Read the entire page →
From page 90...
... Predictions such as the size and extent of the plume as it evolves over time, the total volume of water exceeding the Safe Water Drinking Act standards, and the mass flux of radionuclides to the lower aquifer must be placed in a probabilistic framework. For the purpose of the study discussed in this report, which does not yet consider contaminant transport, the QOI is the increase in water volume flowing from the study site into the lower aquifer over the next 1,000 years.
Read the entire page →
From page 91...
... In the former category are processes that cause drastic alteration in rock properties and pore water pressures near the working point and processes that distribute radionuclides in the cavity and beyond. All of these processes occurred in the area surrounding each test site within the first few seconds after a blast.
Read the entire page →
From page 92...
... A key feature of this analysis is that the large number of parameters not constrained by calibration data can be freely varied in the uncertainty analysis, producing a wider range of outcomes for the QOI. This forward model is highly nonlinear and computationally demanding, which makes it difficult to tune and assess UQ methods for this application.
Read the entire page →
From page 93...
... Predictions and Describing Uncertainty The posterior sample of parameter settings given the calibration data (which were found in the previous sec tion) was then propagated forward through the computationally intensive process model, generating an ensemble of predictions for the QOI -- the additional water volume attributable to the effects of nuclear testing, integrated over the study region (outlined in Figure 6.1(a)
Read the entire page →
From page 94...
... Also, even when qualitative information is desired, it is often obtained through a quantitative analysis. This was the case in the case study presented in Section 6.5, in which quantitative information about ground surface subsistence was used to produce qualitative information regarding the prediction uncertainty for the QOI.
Read the entire page →

Key Terms

  • nuclear testing
  • water volume
  • calibration data
  • simulation models
  • test site

  • yucca flat
  • vvuq process
  • prediction uncertainty
  • nevada test
  • performance metrics

  • input parameters
  • lower aquifer
  • monte carlo
  • nuclear tests
  • weapons stockpile

  • key performance
  • uncertain input
  • process model
  • hydraulic head
  • uncertainty quantification

  • computational models
  • physical experiments
  • national nuclear
  • vvuq study
  • nuclear security

  • underground nuclear
  • key assumptions
  • vvuq analyses
  • additional water
  • nevada national


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.