Risk Modeling, Assessment, and Management of Lahar Flow Threat

The 1991 eruption of Mount Pinatubo in the Philippines is considered one of the most violent and destructive volcanic activities in the 20th century. Lahar is the Indonesian term for volcanic ash, and lahar flows resulting from the massive amount of volcanic materials deposited on the mountain's slope posed continued post-eruption threats to the surrounding areas, destroying lives, homes, agricultural products, and infrastructures. Risks of lahar flows were identified immediately after the eruption, with scientific data provided by the Philippine Institute of Volcanology, the U.S. Geological Survey, and other research institutions. However, competing political, economic, and social agendas subordinated the importance of scientific information to policy making. Using systemic risk analysis and management, this article addresses the issues of multiple objectives and the effective integration of scientific techniques into the decision-making process. It provides a modeling framework for identifying, prioritizing, and evaluating policies for managing risk. The major considerations are: (1) applying a holistic approach to risk analysis through hierarchical holographic modeling, (2) applying statistical methods to gain insight into the problem of uncertainty in risk assessment, (3) using multiobjective trade-off analysis to address the issue of multiple decisionmakers and stakeholders in the decision-making process, (4) using the conditional expected value of extreme events to complement and supplement the expected value in quantifying risk, and (5) assessing the impacts of multistage decisions. Numerical examples based on ex post data are formulated to illustrate applications to various problems. The resulting framework from this study can serve as a general baseline model for assessing and managing risks of natural disasters, which the Philippines' lead agency-the National Disaster Coordinating Council (NDCC)-and other related organizations can use for their decision-making processes.     

由现收现付制向基金制转轨的经济学分析

文章讨论了有关养老保险体系转轨的几个基本的经济学问题。首先从宏观经济运行的角度出发探讨了以下两个问题 :为什么要从现收现付制向基金制转轨 ?对于现阶段的中国来说马上向基金制转轨是否是最优的选择 ?文章还阐释了基金制下的收益率的决定因素并对基金制与现收现付制的风险因素进行了比较 ,最后对养老保险体系的改革提出了几点建议     

The Determinants of Trust and Credibility in Environmental Risk Communication: An Empirical Study

This study examines a key component of environmental risk communication; trust and credibility. The study was conducted in two parts. In the first part, six hypotheses regarding the perceptions and determinants of trust and credibility were tested against survey data. The hypotheses were supported by the data. The most important hypothesis was that perceptions of trust and credibility are dependent on three factors: perceptions of knowledge and expertise; perceptions of openness and honesty; and perceptions of concern and care. In the second part, models were constructed with perceptions of trust and credibility as the dependent variable. The goal was to examine the data for findings with direct policy implications. One such finding was that defying a negative stereotype is key to improving perceptions of trust and credibility.     

Culture, Cosmopolitanism, and Risk Management

Most cultural approaches to risk management deal with the connections between the forms of social relations within groups and the risk concerns of those groups. According to these theories, a certain limited set of different relational forms (usually three, four, or five) lead to specific, different and conflicting, risk concerns. In contrast to these theories, cosmopolitanism is an approach to culture that focuses, not on forms of sociality, but on changes among forms—expansions and contractions in the inclusivity of forms and movement by persons from one form of sociality to another. Relative to other cultural theories, cosmopolitanism thus is much more concerned with the solution of risk management problems than with their origins. Cosmopolitanism can be thought of as a cultural continuum, with cosmopolitanism at one end and pluralism at the other. Cosmopolitan persons are more open to cultural change—and thus the solution of risk management problems. In this article, we outline our new theory of cosmopolitanism, describe a method for measuring it and present an experimental study that tests some implications of the theory. Results from the study support the theory by showing that, compared to pluralistic respondents, cosmopolitan respondents are more inclusive in their risk management judgments—that is, they express equal concern for a local and a national issue, whereas the pluralistic respondents express greater concern in the local case. We discuss the risk management implications of a cosmopolitan approach to culture.     

Cybernetic Risk Analysis

The Pearl Harbor case study reveals that risk analysis failure may be caused by any of a number of factors. However, the most important variables are system load, gain, lead time, and lag time. The dynamics of such cybernetic systems analysis constitute an important aspect in this regard. Four different risk management strategies, or organization designs, have been proposed in this paper. Each has a unique combination of the imputed variables and each has a unique cause of surprise, risk analysis failure, and crisis.     

Compliance Versus Risk in Assessing Occupational Exposures

Assessments of occupational exposures to chemicals are generally based upon the practice of compliance testing in which the probability of compliance is related to the exceedance [γ, the likelihood that any measurement would exceed an occupational exposure limit (OEL)] and the number of measurements obtained. On the other hand, workers’ chronic health risks generally depend upon cumulative lifetime exposures which are not directly related to the probability of compliance. In this paper we define the probability of “overexposure” (θ) as the likelihood that individual risk (a function of cumulative exposure) exceeds the risk inherent in the OEL (a function of the OEL and duration of exposure). We regard θ as a relevant measure of individual risk for chemicals, such as carcinogens, which produce chronic effects after long-term exposures but not necessarily for acutely-toxic substances which can produce effects relatively quickly. We apply a random-effects model to data from 179 groups of workers, exposed to a variety of chemical agents, and obtain parameter estimates for the group mean exposure and the within- and between-worker components of variance. These estimates are then combined with OELs to generate estimates of γ and θ. We show that compliance testing can significantly underestimate the health risk when sample sizes are small. That is, there can be large probabilities of compliance with typical sample sizes, despite the fact that large proportions of the working population have individual risks greater than the risk inherent in the OEL. We demonstrate further that, because the relationship between θ and γ depends upon the within- and between-worker components of variance, it cannot be assumed a priori that exceedance is a conservative surrogate for overexposure. Thus, we conclude that assessment practices which focus upon either compliance or exceedance are problematic and recommend that employers evaluate exposures relative to the probabilities of overexposure.     

Perception of Ecological Risk to Water Environments

This paper examines lay and expert perceptions of the ecological risks associated with a range of human activities that could adversely affect water resource environments. It employs the psychometric paradigm pioneered in characterizing perceptions of human health risks, which involves surveys to obtain judgments from subjects about risk items in terms of several important characteristics of the risks. The paper builds on a previous study that introduced ecological risk perception. This second study employs a larger, more diverse sample, a more focused topic area, and comparisons between lay and expert judgments. The results confirm that a small set of underlying factors explain a great deal of variability in lay judgments about ecological risks. These have been termed Ecological Impact, Human Benefits, Controllability , and Knowledge. The results are useful in explaining subjects' judgments of the general riskiness of, and need for regulation of, various risk items. The results also indicate several differences and areas of agreement among the lay and expert samples that point to potential key issues in future ecological risk management efforts for water resources.     

ATSDR Science Panel on the Bioavailability of Mercury in Soils: Lessons Learned

On the basis of discussion and analysis during and following an ATSDR science panel on the bioavailability of mercury in soils, it is apparent that the default assumption of 100% relative bioavailability for mercury-contaminated soils is excessively conservative. However, current knowledge does not allow the development of default assumptions or guidelines for determining relative bioavailability of mercury in soils. Until such default assumptions or guidelines can be developed, site-specific assays of bioavailability, preferably using either animal bioassays or validated in vitro techniques, may provide the best approach for estimating soil-mercury bioavailability.     

Two phase parametric and probabilistic NPV calculations, with possible deferral of disposal of UK nuclear waste as an example

This paper illustrates the value of several particular features of a first phase parametric approach to discounted cash flow (DCF) decision analysis when significant uncertainty is involved. It also illustrates the value of second phase probabilistic approaches to selected parameters for five quite different example reasons. The most controversial example reason concerns the discount rate. The particular example used to illustrate both phases may stimulate general interest because of the important issues involved, but it is argued that the two phase approach as a whole has a wide range of applications for decisions large and small.     

Earthquake Risk Perception in Bucharest, Romania

The Municipality of Bucharest is one of the capitals with the highest seismic risk in the world. Bucharest is particularly vulnerable to seismic hazard due to: the high density of inhabitants, especially within the residential districts with blocks of flats; the old public utility fund; the out-of-date infrastructure; the numerous industrial parks that are undergoing a restructuring process, not to mention the inefficient organization of civil protection and poor education of the population regarding seismic risk. This research was designed to examine the attitudes and perceptions of people living with the risk of an earthquake hazard in Bucharest. We were interested in how attitudes and perceptions differ depending on gender, age, education, residential area and socioeconomic status, characteristics of seismic hazard, degree of risk exposure, degree of danger, and casualty awareness. At the same time, we compare the results of this study with those from a previous and similar enquiry in 1997. The statistical processing has indicated a significant difference between the declared perception of seismic risk and the independent variables of gender, age, level of education, level of attachment to the residential area, and degree to which the subjects consider they may be affected and could retrieve their losses. Due to the continuous decrease of their living standard, the most vulnerable is the aged population. The feelings toward the residential area is another factor of statistical significance for the population's seismic danger perception. A strong affective bond offers a feeling of safety and leads to the neglect and even total denial of the hazard. In the case of independent variables regarding the type of dwelling, its age, and property form, deviations of empiric values from the theoretical distribution are not relevant for the correlation searched for, which indicates that this issue goes beyond the above-mentioned criteria.