Exposure mixtures settings

Calculation settings

Table 120 Calculation settings for module Exposure mixtures.
Name Type Description
Sparseness parameter

Numeric

Sparseness parameter. Value between 0 (not sparse, many substances) and 1 (sparse, few substances).
SNMU: number of mixtures

Numeric

The number of mixtures to select in SNMU.
Iterations

Numeric

Maximum number of iterations, e.g. 1000.
Seed for pseudo-random number generator.

Numeric

Random seed for initialising matrix W and H.
Substance weighting
ExposureApproachType Risk based (exposures in equivalents of the reference substance) or standardised (standardised exposures per substance have variance 1).
Convergence criterion

Numeric

Convergence criterion for factorisation algorithm.
Cutoff MCR

Numeric

For selection of individual(day) exposures with maximum cumulative ratio (MCR = total exposure/maximum) above the cutoff.
Cutoff percentage in population ranked on total exposure

Numeric

For selection of individual(day) exposures above the cutoff percentage in the set of individual(day)s ranked on total exposure.
Target level
TargetLevelType Select to express hazard characterisations at external or internal exposure level. For an aggregate assessement, that is dietary and nondietary exposure data are combined, the target dose level is always internal. When only dietary exposures are available, the target dose level is optional, i.c. external or internal.
Internal concentration
InternalConcentrationType Internal concentrations are derived form dietary and/or non-dietary concentrations and aggregated using a kinetic or absorption factor model or are human monitoring concentrations.
Number of clusters

Numeric

Number of clusters for hierarchical cluster analysis or clustering minimizing within-cluster variance (k-means).
Method
ClusterMethodType After mixture selection, a clustering maybe applied on the individuals coefficents matrix V (or H) using K-Means or hierarchical clustering to identify populations sub-groupings.
Determine number of clusters automatically

Boolean

For hierarchical clustering the number of clusters is determined automatically.
Network analysis typemethod
NetworkAnalysisType Network analysis on the substance x mixture (U) matrix.