ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00188.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Estimating the potential health risk encountered by workers due to their exposure to various chemicals is enormously complex, since many chemicals be involved and each may have multiple toxic effects. As an aid to this estimation process, a computer program, or model, which computes index numbers expressing the relative health risk of occupational groups due to their potential chemical exposures was developed at the National Institute for Occupational Safety and Health (NIOSH). This model considers an inventory of the chemicals to which specific occupational groups are potentially exposed, the published information regarding the toxic effects of each chemical, and the conditions of occupational exposure. The system then develops indices of potential occupational group health risk by considering weighted combinations of eight distinct health effects. No direct comparison with external occupational risk indices is currently possible, but internal testing of the model reveals no obvious inconsistencies.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00189.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Every source of liquid pollutants lies somewhere on a watershed. Leachwaters derived from water percolating through solid waste deposits and liquid effluents from industry are diluted on their way down the river until they interact with man or particular environmental systems. This environmental dilution of potentially toxic effluents has to be estimated in assessing health and environmental risks. The problem for the risk assessor is to find an appropriate mathematical model. In this paper, the recent mathematical theory of fractal objects is used to demonstrate that, within certain limits, rivers of all lengths and their river basins are self‐similar. Simple general relations exist, therefore, between the length and drainage area of rivers both large and small. These relations and a few additional assumptions are then used to derive an improved set of models for estimating environmental dilution of some pollutant

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00190.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

We emphasize the distinction between two forms of uncertainty that arise in risk and reliability analyses: (1) that due to the randomness inherent in the system under investigation and (2) that due to the vagueness inherent in the assessor's perception and judgement of that system. It is proposed that whereas the probabilistic approach to the former variety of uncertainty is an appropriate one, the same may not be true of the latter. Through seeking to quantify the imprecision that characterizes our linguistic description of perception and comprehension, fuzzy set theory provides a formal framework for the representation of vagueness. In connection with the second form of uncertainty, fuzzy sets and the associated theory of “possibility” are considered as a basis upon which to model the imprecision and vagueness attached to the expert judgement of event likelihood (e.g. component failure). It is noted that from the perspective of the technical complexity of propagation, the possibilistic treatment of uncertainty compares favorably with the more familiar Bayesian appro

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00191.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

This paper introduces stochastic dominance as a technique to reduce the set of possible actions that a decision maker must consider in a decision problem under risk. The procedure usually does not choose an optimal action, but instead eliminates certain actions as unacceptable. Very little need be known about the decision maker's utility function. Two possible applications are presented: (1) upgrading buildings to better withstand an earthquake; and (2) choosing a site for a LNG facility.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00192.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A model is developed for the detection time of fires in nuclear power plants, which differentiates between competing modes of detection and between different initial fire severities. Our state‐of‐knowledge uncertainties in the values of the model parameters are assessed from industry experience using Bayesian methods. Because the available data are sparse, we propose means to interpret imprecise forms of evidence to the develop quantitative information, which can be used in a statistical analysis; the intent is to maximize our use of all available information. Sensitivity analyses are performed to indicate the importance of structural and distributional assumptions made in the study. The methods used to treat imprecise evidence can be applied to a wide variety of problems. The specific equations developed in this analysis are useful in general situations, where the random quantity of interest is the minimum of a set of random variables (e.g., in “competing risks” models). The computational results indicate that the competing modes formulation can lead to distributions different from those obtained via analytically simpler models, which treat each mode independently of the

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00193.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

This is a report on the Environmental Protection Agency's (EPA's) efforts to communicate with the public about the risks of ethylene dibromide (EDB), what the agency said it was doing about these risks and what information the public actually received through television and newspapers. Although special in many ways, the EDB case illustrates the problems that regulatory agencies have when they must take regulatory action and assure the public that the risks in question are being dealt with adequately. It also illustrates issues that the press faces. Above all, it illustrates the barriers to communication presented by the different perspectives of regulatory agencies and individuals and the types of information they each are most interested in.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00194.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A simple relationship is formulated that helps to discriminate between acceptable and unacceptable individual lifetime risks (RL) to populations that are exposed to chemical carcinogens. The relationship is an empirical one and is developed using objective risk data as well as subjective risk levels that have found substantial acceptance among those concerned with carcinogenic risk assessment issues. The expression sets acceptable levels of lifetime carcinogenic risk and is a function of the total population exposed to the carcinogen. Its use in risk assessment and risk management provides guidance in distinguishing those carcinogens that should be regulated because of the health hazard they pose from those whose regulation may not be needed.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00195.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The risk homeostasis theory posits, in essence, that a control mechanism analogous to the thermal homeostatic system in warm‐blooded animals tends to keep risk per unit time constant, and, as a consequence, the number of traffic accidents per unit time of driving also tends to remain constant, essentially independent of changes in the traffic safety system. It is the purpose of the present research to examine the validity of this claim using a wide variety of traffic accident data. All the data examined are found to be incompatible with the risk homeostasis theory. The only specific field accident data offered in the literature to support the risk homeostasis theory are found to, in fact, refute the theory. The accident data provide evidence that a rich variety of user responses occur. While it is possible for users to collectively respond in such a way that safety benefits are completely cancelled, such a response is not particularly common; it is certainly not universally occurring, as suggested by the risk homeostasis theory. It is concluded that the risk homeostasis theory should be rejected because there is no convincing evidence supporting it and much evidence refuting i

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00196.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A quick and summary comment is made on a paper by Evans,(1)who set out to “definitively answer” the question “whether there is any validity” in risk homeostasis theory (RHT), and who arrives at the conclusion that the “theory should be rejected” because the data “provide the clearest evidence refuting the theory.” It will be argued here that the seven cases Evans puts forward against RHT do not justify such a rather boldly‐worded conclusion. On the contrary, the data presented by Evans can be seen to be either not inconsistent with RHT (Case 1), in error (Case 2), or fail to take account of relevant economic changes (Case 3) and of pertinent exposure variables (Case 5), incomplete or the product of guesswork (Case 4), irrelevant (Case 6), nonrepresentative (Case 7) and in all cases open to alternative interpretations that do not conflict with the theory under debate. Moreover, Evans’reasoning seems to betray not only careless reading of what RHT does in fact say, but also a fundamental misunderstanding of the notion of target risk in particular. Refuting a “refutation” does not, of course, imply that RHT is valid, or valid at least within as yet to be defined limits. Attempts to address the validity question should preferably take the form of well‐controlled field experiments, instead of retrospective analyses of multünterpretable archival data that

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1986.tb00197.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY