Sensitivity and Uncertainty Analyses

Possession of a comprehensive mechanism and a suitable integration scheme does not mean that a chemical process is well understood. Particularly for large mechanisms with many species, it is not easy to understand the competition between reaction steps or the coupling between species. We shall see that sensitivity analysis and components of the mechanism reduction techniques described below, provide a good method of under- 

There are no direct methods for the inspection of the stoichiometric information. If a reaction proves to be redundant by one of the methods described in the next section, then obviously the stoichiometric information of the reaction is not important. Methods for the analysis of time-scales (see Section 4.8) can also provide hints for the transformation of reaction systems without losing stoichiometric information. A good global reaction scheme is the minimal reaction system that contains all the stoichiometric information of the detailed mechanism. In Sections 4.8 to 4.10, a series of methods will be presented for the generation of global reaction schemes. 

The family of methods for the study of parametric information in mathematical models is called sensitivity analysis. Sensitivity analysis investigates the relationship between the parameters and the output of any model. It is usually used for two purposes first, for uncertainty analysis and, second, for gaining insight into the model. Sensitivity methods in chemical kinetics have been reviewed by Rabitz et al. [64], who concentrated mainly on the interpretation of sensitivity coefficients in reaction-diffusion systems. Turdnyi [12] considered sensitivity methods as tools for studying reaction kinetics problems and reviewed several applications. Recently, Radha- 

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Perform sensitivity and uncertainty analysis. Calculation of life-cycle costs and net benefits assumes that cash-flow profiles and the value of MARR are reasonably accurate. In most cases, uncertain assumptions and estimates are made in developing cash flow profile forecasts. Sensitivity analysis can be performed by testing how the outcome changes as the assumptions and input values change. 

Blower SM, Dowlatabadi H. Sensitivity and uncertainty analysis of complex models of disease transmission an HIV model, as an example. Int Statistical Rev 1994 62 229-43. 

Gao, D W. R. Stockwell, and J. B. Milford, First-Order Sensitivity and Uncertainty Analysis for a Regional-Scale Gas-Phase Chemical Mechanism, J. Geophys. Res., 100, 23153-23166 (1995). 

Given the data challenges discussed previously and the increasing use of streamlined methods, it is necessary to continuously improve the consistency and transparency of the information and the assumptions used in such tools to ensure the quality and the validity of the decisions made with the aid of LGA metrics. The inclusion of quality indicators (such as sensitivity and uncertainty analysis) will continue to be an important step to estimate the uncertainties involved in the inventory and impact models. Finally, there is a need to continuously perform peer review assessments by LGA experts, as the current LGA expertise in pharmaceuticals is very limited. When these requirements are fulfilled, LGA metrics are powerful tools to aid the decision making leading to more sustainable pharmaceutical processes. For further examples of FLASG scores and other LGA analyzes being applied, see Section 10.4.1. 

Vardoulakis S, Fisher BEA, Gonzalez-Flesca N, Pericleous K (2002) Model sensitivity and uncertainty analysis using roadside air quality measurements. Atmos Environ 36 2121-2134... 

Isukapalli SS, Georgopoulos PG (2001) Computational methods for sensitivity and uncertainty analysis for environmental and biological models. Research Triangle Park, NC, United States Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, 145 pp. (EPA/600/R-01-068 http //www.ccl.rutgers.edu/reports/EPA/edmas v3 epa.pdf). 

Methods of numerical sensitivity and uncertainty analysis can be used to examine uncertainty and identify the key sources of bias and imprecision in quantitative estimates of risk. Once identified, limited resources (e.g., time, funding) can be efficiently allocated to obtain new information and data for those major sources of uncertainty and reduce it. These analyses can be repeated until uncertainties associated with the risk estimates are of an acceptable degree or until uncertainties cannot be further reduced. 

The guidance material available via WISF-RTD covers more general topics such as guidance on the use of tools (e.g. model selection, model linking, model calibration and validation, model sensitivity and uncertainty analysis, etc.), the monitoring process, the stakeholder participation, etc. Such technical guidances are set up by various RTD... 

For any value the used experimental method is stored, together with the respective ionic strength, the background media, and other information necessary to evaluate the data or derive other values. If published, errors for numerical data are included as a prerequisite for sensitivity and uncertainty analysis. 

Perform sensitivity and uncertainty analysis for different system contributions to the total core melt frequency ... 

Guo M, Murphy RJ. LCA data quality sensitivity and uncertainty analysis. Sci Total Environ... 

Katakura J. and lijima S., Analysis of Uncertainties in Summation Calculations of Decay Heat Using JNDC FP, Nuclear Data Library. Jour. Nucl. Sci + Tech. 29, p. 11 (1992). Also Rebah J. et al., Sensitivity and Uncertainty Analysis for Fission Product Decay Heat Calculations, Proc. Int. Conf on Radiation Shielding p. 63, Arlington, USA (1994). 

The robustness of the risk analysis results has been checked by means of sensitivity and uncertainty analysis. 

The CAPP code (Lee et al., 2012a,b) is used for the analysis of core physics parameters of VHTR using the few-group parameters generated by DeCART. The sensitivity and uncertainty analysis code, MUSAD (Han et al., 2015), is being developed for an uncertainty analysis of the few-group parameters generated by DeCART and eventually the uncertainty of the core physics parameters evaluated by the CAPP code. Fig. 13.11 shows the two-step neutronics analysis code system for the VHTR developed at KAERI. 

Han, T.Y., et al.. May 03—06, 2015. Verification of a sensitivity and uncertainty analysis code based on GPT using MHTGR-350 benchmark. In Proceedings of ICAPP 2015, France. 

Tomlin, A.S. The role of sensitivity and uncertainty analysis in combustion modelling. Proc. Combust. Inst. 34, 159-176 (2013)... 

Derwent, R., Hov, 0. Application of sensitivity and uncertainty analysis techniques to a photochemical ozone model. J. Geophys. Res. Atm. 93, 5185-5199 (1988)... 

Gao, D., Stockwell, W.R., Milford, J.B. First-order sensitivity and uncertainty analysis for a regional-scale gas-phase chemical mechanism. J. Geophys. Res. Atm. 100, 23153-23166... 

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