Probabilistic Risk Analysis for a High-Level Radioactive Waste Repository

A probabilistic risk analysis (PRA) for a high-level radioactive waste repository is very important since it gives an estimate of its health impacts, allowing comparisons to be made with the health impacts of competing technologies. However, it is extremely difficult to develop a credible PRA for a specific repository site because of large uncertainties in future climate, hydrology, geological processes, etc. At best, such a PRA would not be understandable to the public. An alternative proposed here is to develop a PRA for an average U.S. site, taking all properties of the site to be the U.S. average. The results are equivalent to the average results for numerous randomly selected sites. Such a PRA is presented here; it is easy to understand, and it is not susceptible to substantial uncertainty. Applying the results to a specific repository site then requires only a simple, intuitively acceptable "leap of faith" in assuming that with large expenditures of effort and money, experts can select a site that would be at least as secure as a randomly selected site.     

Decidedly Different: Expert and Public Views of Risks from a Radioactive Waste Repository

A questionnaire with items that had been used in a national survey of the general public was administered to persons attending an American Nuclear Society meeting. The items asked about risks associated with high-level nuclear waste (HLNW), trust in nuclear-waste program managers, costs and benefits of a repository project, and images of a HLNW repository. The results suggest that nuclear industry experts may have very different opinions from the general public about most of these items and their images of a repository indicate a vastly different conceptual framework within which their opinions are formed.     

基于改进语言评估标度的专家后验权重确定方法研究

针对大型复杂项目的高度不确定性,专家评价的模糊性和差异性等特点,本文给出了一种实用的语言评估新标度,并提出了不确定扩展语言信息的概念。利用改进的语言评估标度分别探讨确定语言信息、不确定语言信息及不确定扩展语言信息下的专家后验权重的确定方法,认为前两者均为后者的特殊表现形式。最后用型号项目风险评价实例证明了方法的科学有效性以及评价结果的合理性。     

Waste Package Performance Evaluations for the Proposed High-Level Nuclear Waste Repository at Yucca Mountain

The evaluation studies of the proposed repository for long-term storage of spent nuclear fuel and high-level nuclear waste at Yucca Mountain, Nevada, are underway. Fulfillment of the requirements for limiting dose to the public, which includes containment of the radioactive waste emplaced in the proposed repository and subsequent slow release of radionuclides from the Engineered Barrier System (EBS) into the geosphere, will rely on a robust waste container design, among other EBS components. Part of the evaluation process involves sensitivity studies aimed at elucidating which model parameters contribute most to the waste package and overlying drip shield degradation characteristics. The model parameters identified for this study include (1) general corrosion rate parameters and (2) stress corrosion cracking (SCC) parameters. Temperature dependence and parameter uncertainty are evaluated for the general corrosion rate model parameters while for the SCC model parameters, uncertainty treatment of stress intensity factor, crack initiation threshold, and manufacturing flaw orientations are evaluated. Based on these evaluations new uncertainty distributions are generated and recommended for future analyses. Also, early waste package failures due to improper heat treatment were added to the waste package degradation model. The results of these investigations indicate that the waste package failure profiles are governed by the manufacturing flaw orientation model parameters.     

Effects of key enabling technologies for seru production on sustainable performance

Demand uncertainty, economic globalization, and environmental deterioration force factories to innovate their manufacturing systems for achieving sustainable performance. Seru production, which is the latest manufacturing mode developed in Japan, attracts broad attention from both academia and practitioners. The overwhelming majority of existing works on seru production focus on economic performance unilaterally, while neglecting the environmental and social performance. This paper investigates the effects of key enabling technologies for seru production on sustainable performance. Firstly, four key enabling technologies for seru production are identified through systematic review, and an evaluation indicator system of sustainable performance in the context of seru production is developed. Then, the hypotheses about the effects of the identified key enabling technologies for seru production on sustainable performance are proposed on the basis of previous research achievements, theoretical analysis, and practical observations. Finally, the hypotheses are tested through structural equation modeling. Except for two hypotheses which are not supported and one which is indirectly supported, all other hypotheses are verified. The research results show that the four key enabling technologies for seru production have different effects on the three dimensions of sustainable performance. The achievements of this work are of significance to improve the comprehensive understanding of seru production, as well as to develop practical methods to implement sustainable operations.     

Selection system orientations as an explanation for the differences between dual leaders of the same organization in their perception of organizational performance

We investigate to what extent individual managers operating in a dual leadership structure have different perceptions of how well his/her organization is performing. Using selection system theory we develop hypotheses on the relationships between a leader’s selection system orientation and his/her perception of performance along multiple dimensions: market performance, expert performance and peer performance. The hypotheses are tested using dyadic data from 59 organizations in the performing arts led by two—hierarchically equivalent—managers. Our results show that dual leaders’ differences in terms of market orientation and expert orientation relate positively to perceived performance differences along the same dimensions. This relationship is not found with respect to peer selection orientation. Generally, the relationship between orientation differences and perceived performance differences is stronger if the process of interpreting signals to construct a perception of organizational performance leaves more room for equivocality and uncertainty.     

Deliberative Disjunction: Expert and Public Understanding of Outcome Uncertainty

Many environmental and risk management decisions are made jointly by technical experts and members of the public. Frequently, their task is to select from among management alternatives whose outcomes are subject to varying degrees of uncertainty. Although it is recognized that how this uncertainty is interpreted can significantly affect decision‐making processes and choices, little research has examined similarities and differences between expert and public understandings of uncertainty. We present results from a web‐based survey that directly compares expert and lay interpretations and understandings of different expressions of uncertainty in the context of evaluating the consequences of proposed environmental management actions. Participants responded to two hypothetical but realistic scenarios involving trade‐offs between environmental and other objectives and were asked a series of questions about their comprehension of the uncertainty information, their preferred choice among the alternatives, and the associated difficulty and amount of effort. Results demonstrate that experts and laypersons tend to use presentations of numerical ranges and evaluative labels differently; interestingly, the observed differences between the two groups were not explained by differences in numeracy or concerns for the predicted environmental losses. These findings question many of the usual presumptions about how uncertainty should be presented as part of deliberative risk‐ and environmental‐management processes.     

A Multinomial‐Dirichlet Model for Analysis of Competing Hypotheses

Analysis of competing hypothesis, a method for evaluating explanations of observed evidence, is used in numerous fields, including counterterrorism, psychology, and intelligence analysis. We propose a Bayesian extension of the methodology, posing the problem in terms of a multinomial‐Dirichlet hierarchical model. The yet‐to‐be observed true hypothesis is regarded as a multinomial random variable and the evaluation of the evidence is treated as a structured elicitation of a prior distribution on the probabilities of the hypotheses. This model provides the user with measures of uncertainty for the probabilities of the hypotheses. We discuss inference, such as point and interval estimates of hypothesis probabilities, ratios of hypothesis probabilities, and Bayes factors. A simple example involving the stadium relocation of the San Diego Chargers is used to illustrate the method. We also present several extensions of the model that enable it to handle special types of evidence, including evidence that is irrelevant to one or more hypotheses, evidence against hypotheses, and evidence that is subject to deception.     

基于信任关系和信息测度的概率语义社会网络群决策模型

设计专家权重和属性指标权重的计算模型已成为近年来备受关注的两个重要研究课题。针对评价信息为概率语义信任函数的社会网络群决策问题,提出一种基于信任关系和信息测度的概率语义社会网络群决策模型。首先,构建基于信任关系的概率语义决策空间,探究专家之间的信任传递模型,通过专家之间信任关系计算专家的权重;其次,引入概率语义信任函数的熵和相似度概念,并运用三角函数设计概率语义信任函数信息熵和相似度的衡量方法;最后,构建基于信任关系和信息测度的概率语义社会网络群决策模型,进而得到合理可靠的决策结果,同时将提出的社会网络群决策模型用于电动汽车供应商的选择实例,对比分析实验验证了模型的合理性和有效性。     

基于非均匀性语言标度和DLWA算子的动态绩效模糊群决策研究

基于企业人力资源管理(HRM)系统中职能管理部门年度绩效考核决策评价和选优序列生成过程中的数据的不确定性、随机性和模糊性,通过设计季度绩效多维度模糊评价体系,采用非均匀加性语言评估标度定性的多维度评价,构建动态加性语言判断矩阵模型,利用DLWA算子等语言信息集成算子,集成多个决策者不同时期绩效指标评价数据,并整合不同决策者的偏好度,综合呈现年度部门业绩选优序列,优化提升职能管理部门绩效考核决策的精确性、公平性和可信度。     

科学基金项目立项评估:综合评价信息可靠性的多指标证据推理规则研究

公正合理的科研项目立项评估与选择是国家自然科学基金管理活动的关键环节。综合考虑科研项目的评估指标体系和选择流程,提出了利用历史评估准确性度量专家提供信息可靠性的方法,进而提出了一种系统性的基于证据推理规则的科学基金项目评估决策模型。该模型使用证据推理合成规则对多专家多指标评估信息进行集结。在集结过程中：充分考虑评估指标的权重以及评估等级的多样性;鉴于参与项目评估的专家具有不同的知识背景和经验,提出利用历史评估结果的准确性衡量专家提供的评价信息可靠性的方法;应用信度分布表征项目的整体评价结果,包含了更丰富的信息。国家自然科学基金项目评估的实例分析证明了该评估决策模型的有效性。     

评审专家抽取中的时间距离约束分析

针对现有评审专家抽取中距离约束存在的不足,本文提出了一种新的时间距离约束。本文介绍了时间距离的含义及其提出的必要性,并给出了基于GIS技术的时间距离计算方法,具体包括相关假设、计算步骤、解决方案以及实现过程。时间距离约束的提出不仅可以保证所有被选专家都可按时到达评审地点,而且还能打破行政区域的限制,合理调配专家资源,具有重要的现实意义。     

Performance Assessments of Nuclear Waste Repositories: A Dialogue on Their Value and Limitations

Performance Assessment (PA) is the use of mathematical models to simulate the long-term behavior of engineered and geologic barriers in a nuclear waste repository; methods of uncertainty analysis are used to assess effects of parametric and conceptual uncertainties associated with the model system upon the uncertainty in outcomes of the simulation. PA is required by the U.S. Environmental Protection Agency as part of its certification process for geologic repositories for nuclear waste. This paper is a dialogue to explore the value and limitations of PA. Two skeptics acknowledge the utility of PA in organizing the scientific investigations that are necessary for confident siting and licensing of a repository; however, they maintain that the PA process, at least as it is currently implemented, is an essentially unscientific process with shortcomings that may provide results of limited use in evaluating actual effects on public health and safety. Conceptual uncertainties in a PA analysis can be so great that results can be confidently applied only over short time ranges, the antithesis of the purpose behind long-term, geologic disposal. Two proponents of PA agree that performance assessment is unscientific, but only in the sense that PA is an engineering analysis that uses existing scientific knowledge to support public policy decisions, rather than an investigation intended to increase fundamental knowledge of nature; PA has different goals and constraints than a typical scientific study. The proponents describe an ideal, six-step process for conducting generalized PA, here called probabilistic systems analysis (PSA); they note that virtually all scientific content of a PA is introduced during the model-building steps of a PSA; they contend that a PA based on simple but scientifically acceptable mathematical models can provide useful and objective input to regulatory decision makers. The value of the results of any PA must lie between these two views and will depend on the level of knowledge of the site, the degree to which models capture actual physical and chemical processes, the time over which extrapolations are made, and the proper evaluation of health risks attending implementation of the repository. The challenge is in evaluating whether the quality of the PA matches the needs of decision makers charged with protecting the health and safety of the public.     

基于Mo-RVIKOR的混合多属性决策方法

针对复杂性和不确定性多属性决策问题，考虑定量和定性融合的属性形式，提出了模块化随机多准则妥协解排序法（Modular Random VlseKriterijumska Opti-mizacija I Kompromisno Resenje，Mo-RVIKOR），该方法无需将信息统一，就能处理多种信息形式存在的多属性决策问题。采用精确数、随机变量处理定量评价信息，用概率语义术语集处理定性评价信息；通过改进离差最大化法确定属性权重；根据Mo-RVIKOR对决策对象进行排序；最后以某公司C2B定制化服务质量评测项目为例，验证了所提方法的有效性。     

三元效率区间下决策单元的全局绩效评价

针对现实生活中投入产出数据的不确定性,许多学者提出从乐观和悲观角度计算决策单元的效率区间,但每个效率区间的上、下界值都是决策单元表现的两种极端情况。本文通过引入心态指标衡量决策者的偏好,获得了一个最有可能的效率值,它与上界值、下界值共同组成了三元效率区间。然后改进了两级排序方法:提出了三元有向距离指数,为所有决策单元获得全序化结果。本文引用前人文中的数例验证了该方法是一种更为精确、可全序化的评价、决策方法,可广泛应用于效率测评中。     

Explosion Probability of Unexploded Ordnance: Expert Beliefs

This article reports on a study to quantify expert beliefs about the explosion probability of unexploded ordnance (UXO). Some 1,976 sites at closed military bases in the United States are contaminated with UXO and are slated for cleanup, at an estimated cost of $15–140 billion. Because no available technology can guarantee 100% removal of UXO, information about explosion probability is needed to assess the residual risks of civilian reuse of closed military bases and to make decisions about how much to invest in cleanup. This study elicited probability distributions for the chance of UXO explosion from 25 experts in explosive ordnance disposal, all of whom have had field experience in UXO identification and deactivation. The study considered six different scenarios: three different types of UXO handled in two different ways (one involving children and the other involving construction workers). We also asked the experts to rank by sensitivity to explosion 20 different kinds of UXO found at a case study site at Fort Ord, California. We found that the experts do not agree about the probability of UXO explosion, with significant differences among experts in their mean estimates of explosion probabilities and in the amount of uncertainty that they express in their estimates. In three of the six scenarios, the divergence was so great that the average of all the expert probability distributions was statistically indistinguishable from a uniform (0, 1) distribution—suggesting that the sum of expert opinion provides no information at all about the explosion risk. The experts' opinions on the relative sensitivity to explosion of the 20 UXO items also diverged. The average correlation between rankings of any pair of experts was 0.41, which, statistically, is barely significant (p= 0.049) at the 95% confidence level. Thus, one expert's rankings provide little predictive information about another's rankings. The lack of consensus among experts suggests that empirical studies are needed to better understand the explosion risks of UXO.     

Quantifying the Effects of Expert Selection and Elicitation Design on Experts’ Confidence in Their Judgments About Future Energy Technologies

Expert elicitations are now frequently used to characterize uncertain future technology outcomes. However, their usefulness is limited, in part because: estimates across studies are not easily comparable; choices in survey design and expert selection may bias results; and overconfidence is a persistent problem. We provide quantitative evidence of how these choices affect experts’ estimates. We standardize data from 16 elicitations, involving 169 experts, on the 2030 costs of five energy technologies: nuclear, biofuels, bioelectricity, solar, and carbon capture. We estimate determinants of experts’ confidence using survey design, expert characteristics, and public R&D investment levels on which the elicited values are conditional. Our central finding is that when experts respond to elicitations in person (vs. online or mail) they ascribe lower confidence (larger uncertainty) to their estimates, but more optimistic assessments of best‐case (10th percentile) outcomes. The effects of expert affiliation and country of residence vary by technology, but in general: academics and public‐sector experts express lower confidence than private‐sector experts; and E.U. experts are more confident than U.S. experts. Finally, extending previous technology‐specific work, higher R&D spending increases experts’ uncertainty rather than resolves it. We discuss ways in which these findings should be seriously considered in interpreting the results of existing elicitations and in designing new ones.     

Probability and Possibility‐Based Representations of Uncertainty in Fault Tree Analysis

Expert knowledge is an important source of input to risk analysis. In practice, experts might be reluctant to characterize their knowledge and the related (epistemic) uncertainty using precise probabilities. The theory of possibility allows for imprecision in probability assignments. The associated possibilistic representation of epistemic uncertainty can be combined with, and transformed into, a probabilistic representation; in this article, we show this with reference to a simple fault tree analysis. We apply an integrated (hybrid) probabilistic‐possibilistic computational framework for the joint propagation of the epistemic uncertainty on the values of the (limiting relative frequency) probabilities of the basic events of the fault tree, and we use possibility‐probability (probability‐possibility) transformations for propagating the epistemic uncertainty within purely probabilistic and possibilistic settings. The results of the different approaches (hybrid, probabilistic, and possibilistic) are compared with respect to the representation of uncertainty about the top event (limiting relative frequency) probability. Both the rationale underpinning the approaches and the computational efforts they require are critically examined. We conclude that the approaches relevant in a given setting depend on the purpose of the risk analysis, and that further research is required to make the possibilistic approaches operational in a risk analysis context.     

MATERIAL PLANNING FOR A REMANUFACTURING FACILITY

This article describes the first fully integrated material planning system to facilitate the management of a remanufacturing facility. A number of firms are already engaged in this activity. They remanufacture automobile, truck, and other vehicle components, like starters, alternators, transmissions, and so forth. These firms take in used components, disassemble them, and assemble saleable products from the good parts they find. There is considerable uncertainty in the supply of used components, the good parts in those components, and the demand for remanufactured products. Our system is based on material requirements planning logic, something that many firms in the industry are already familiar with. Meetings with experts in the industry were used to set the parameters of the system and evaluate its approach.     

区域多元化抑或产品多元化?制度环境约束下民营企业核心能力构建与成长战略选择

在文献与理论研究的基础上,构建了制度环境、核心能力与企业成长战略选择之间关系的概念模型,并提出了相关假设。然后,以中国民营上市公司2007-2014年数据为对象进行实证检验,结果发现:市场化程度更高的区域,民营企业倾向于构建"行业专家"型核心能力,进而倾向于选择"做强"的区域多元化战略;市场化程度相对较低的区域,民营企业更多倾向于构建"社会资本"型核心能力,进而会选择"做大"的产品多元化战略。上述发现为企业成长与多元化战略理论补充了新的内容。