Comparison of machine learning approaches and statistical methods for estimation of airborne chemical exposures

Accurate quantitative estimation of exposure using retrospective data has been one of the most challenging tasks in the exposure assessment field. To improve these estimates, some models have been developed using published exposure databases with their corresponding exposure determinants. These models are designed to be applied to reported exposure determinants obtained from study subjects or exposure levels assigned by an industrial hygienist, so quantitative exposure estimates can be obtained. ^ In an effort to improve the prediction accuracy and generalizability of these models, and taking into account that the limitations encountered in previous studies might be due to limitations in the applicability of traditional statistical methods and concepts, the use of computer science- derived data analysis methods, predominantly machine learning approaches, were proposed and explored in this study. ^ The goal of this study was to develop a set of models using decision trees/ensemble and neural networks methods to predict occupational outcomes based on literature-derived databases, and compare, using cross-validation and data splitting techniques, the resulting prediction capacity to that of traditional regression models. Two cases were addressed: the categorical case, where the exposure level was measured as an exposure rating following the American Industrial Hygiene Association guidelines and the continuous case, where the result of the exposure is expressed as a concentration value. Previously developed literature-based exposure databases for 1,1,1 trichloroethane, methylene dichloride and, trichloroethylene were used. ^ When compared to regression estimations, results showed better accuracy of decision trees/ensemble techniques for the categorical case while neural networks were better for estimation of continuous exposure values. Overrepresentation of classes and overfitting were the main causes for poor neural network performance and accuracy. Estimations based on literature-based databases using machine learning techniques might provide an advantage when they are applied to other methodologies that combine `expert inputs' with current exposure measurements, like the Bayesian Decision Analysis tool. The use of machine learning techniques to more accurately estimate exposures from literature-based exposure databases might represent the starting point for the independence from the expert judgment.^

Chemical selection methods : an annotated bibliography /

Mode of access: Internet.

Rapid methods for the chemical analysis of special steels, steel-making alloys, their ores and graphites,

Table on lining-paper.

The methods of glass blowing and of working silica in the oxy-gas flame, for the use of chemical and physical students /

Mode of access: Internet.

Methods for the chemical analysis of uranium monocarbide /

"Contract AT(30-1)-2789."

Technical methods of chemical analysis,

"A revised edition of Dr. F. Böckmann̓s Chemisch-technische Untersuchungsmethoden, edited by Professor G. Lunge, was published in 1899 ... practically a new work ... adapted to modern methods of work. In 1904 a second edition was called for, in which the whole of the subject matter was thoroughly revised and brought up to date ... The English translation has been made from the second German edition ... A bibliography ... is appended to each section, and all important tables, in addition to having printed in the text, are also printed for reference at the end of each volume."-Pref.

Chemical thermodynamics; basic theory and methods,

Bibliographical footnotes. Bibliography: p. 360.

Evaluation of chemical restraint methods for potential use in wild, free roaming horses : final report /

Prepared for the Bureau of Land Management, under Contract YA-512-CT8-116, Washington State University, Pullman.

Standard methods of milk analysis, bacteriological and chemical.

Bibliography at end of each chapter except three.

A practical treatise on warming buildings by hot water; on ventilation, and the various methods of distributing artificial heat, and their effects on animal and vegetable physiology. To which are added, an inquiry into the laws of radiant and conducted heat, the chemical constitution of coal, and the combustion of smoke.

"In the present work there have been incorporated several papers ... which have been read before the Institution of Civil Engineers; and also the author's articles on 'Stoves' and 'Ventilation,' published in the Encyclopædia metropolitana."--Pref.

The chemical laundry guide; a work designed to teach ladies the art of laundrying clothes according to chemical principals [!] and the superior methods employed by city laundries; containing a full and explicit treatise on linen polishing, and the skillful washing and renovation of articles of every material. Over three hundred laundry methods.

Mode of access: Internet.

Methods for microbiological and chemical determinations of essential amino acids in proteins and foods /

Cover title.

Standard methods of chemical analysis.

Previous editions edited by W. W. Scott.

Qualitative chemical analysis; a guide in qualitative work, with data for analytical operations and laboratory methods in organic chemistry,

Mode of access: Internet.