2D Monte Carlo versus 2D fuzzy Monte Carlo health risk assessment

Date

2005-02-01

Author

Kentel Erdoğan, Elçin

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

40
views

0
downloads

Risk estimates can be calculated using crisp estimates of the exposure variables (i.e., contaminant concentration, contact rate, exposure frequency and duration, body weight, and averaging time). However, aggregate and cumulative exposure studies require a better understanding of exposure variables and uncertainty and variability associated with them. Probabilistic risk assessment (PRA) studies use probability distributions for one or more variables of the risk equation in order to quantitatively characterize variability and uncertainty. Two-dimensional Monte Carlo Analysis (2D MCA) is one of the advanced modeling approaches that may be used to conduct PRA studies. In this analysis the variables of the risk equation along with the parameters of these variables (for example mean and standard deviation for a normal distribution) are described in terms of probability density functions (PDFs). A variable described in this way is called a "second order random variable." Significant data or considerable insight to uncertainty associated with these variables is necessary to develop the appropriate PDFs for these random parameters. Typically, available data and accuracy and reliability of such data are not sufficient for conducting a reliable 2D MCA. Thus, other theories and computational methods that propagate uncertainty and variability in exposure and health risk assessment are needed. One such theory is possibility analysis based on fuzzy set theory, which allows the utilization of incomplete information (incomplete information includes vague and imprecise information that is not sufficient to generate probability distributions for the parameters of the random variables of the risk equation) together with expert judgment. In this paper, as an alternative to 2D MCA, we are proposing a 2D Fuzzy Monte Carlo Analysis (2D FMCA) to overcome this difficulty. In this approach, instead of describing the parameters of PDFs used in defining the variables of the risk equation as random variables, we describe them as fuzzy numbers. This approach introduces new concepts and risk characterization methods. In this paper we provide a comparison of these two approaches relative to their computational requirements, data requirements and availability. For a hypothetical case, we also provide a comperative interpretation of the results generated.

Subject Keywords

Environmental Engineering, General Environmental Science, Safety, Risk, Reliability and Quality, Water Science and Technology, Environmental Chemistry

URI

https://hdl.handle.net/11511/42878

Journal

STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT

DOI

https://doi.org/10.1007/s00477-004-0209-1

Collections

Department of Civil Engineering, Article

Suggestions

OpenMETU
Core

Bayesian Learning and Relevance Vector Machines Approach for Downscaling of Monthly Precipitation OKKAN, UMUT; İnan, Gül (American Society of Civil Engineers (ASCE), 2015-04-01) In this study, statistical downscaling of large-scale general circulation model (GCM) simulations to monthly precipitation of Kemer Dam, in Turkey, has been performed through relevance vector machines (RVMs). All possible regression methods along with statistical measures have been used to select potential predictors through reanalysis data providing air850, hgt850, and prate variables as the optimal. The determined explanatory variables are then used for training RVM-based statistical downscaling model. A ...
Periodic stationarity conditions for periodic autoregressive moving average processes as eigenvalue problems Ula, TA; Smadi, AA (American Geophysical Union (AGU), 1997-08-01) The determination of periodic stationarity conditions for periodic autoregressive moving average (PARMA) processes is a prerequisite to their analysis. Means of obtaining these conditions in analytically simple forms are sought. It is shown that periodic stationarity conditions for univariate and multivariate PARMA processes can always be reduced to eigenvalue problems, which are computationally and analytically easier to deal with. Two different lumpings of the periodic process are considered along this li...
Estimation of rate constants of PCB dechlorination reactions using an anaerobic dehalogenation model KARAKAS, Filiz; İmamoğlu, İpek (Elsevier BV, 2017-02-15) This study aims to estimate anaerobic dechlorination rate constants (k(m)) of reactions of individual PCB congeners using data from four laboratory microcosms set up using sediment from Baltimore Harbor. Pathway km values are estimated by modifying a previously developed model as Anaerobic Dehalogenation Model (ADM) which can be applied to any halogenated hydrophobic organic (HOC). Improvements such as handling multiple dechlorination activities (DAs) and co-elution of congeners, incorporating constraints, ...
Risk tolerance measure for decision-making in fuzzy analysis: a health risk assessment perspective Kentel Erdoğan, Elçin (Springer Science and Business Media LLC, 2007-05-01) In risk assessment studies it is important to determine how uncertain and imprecise knowledge should be included into the simulation and assessment models. Thus, proper evaluation of uncertainties has become a major concern in environmental and health risk assessment studies. Previously, researchers have used probability theory, more commonly Monte Carlo analysis, to incorporate uncertainty analysis in health risk assessment studies. However, in conducting probabilistic health risk assessment, risk analyst ...
Analysis of the heterogeneity scale effects on pump and treat aquifer remediation design Güngör Demirci, Gamze; Aksoy, Ayşegül; Department of Environmental Engineering (2009) The effect of heterogeneity correlation scale of hydraulic conductivity (K), equilibrium distribution coefficient (Kd) and mass transfer rate on the design and cost of the P&T remediation system for different heterogeneity levels (defined by the variance (σ2lnK)) and parameter distributions under the rate-limited sorption conditions was evaluated in this study. In addition, the impacts of initial amount of contaminant mass and plume configuration on the remediation design and cost were explored. The effects...

Citation Formats

E. Kentel Erdoğan, “2D Monte Carlo versus 2D fuzzy Monte Carlo health risk assessment,” STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT, pp. 86–96, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42878.