预案分析的贝叶斯网络方法

在对预案进行评估分析和执行过程中常会涉及不确定性问题,传统的预案编制工具关键路径法(Critical Path Method,CPM)不具备处理不确定性问题的能力。本文推荐的贝叶斯网络法(Bayesian Networks)因其处理分析不确定性问题的能力已经被广泛应用于一系列的决策支持应用,但对预案评估分析的应用是新颖的。本文介绍了用贝叶斯网络法分析传统关键路径法编制的预案。     

Meta-Functional Benefit Transfer for Wetland Valuation: Making the Most of Small Samples

This study applies functional Benefit Transfer via Meta-Regression Modeling to derive valuation estimates for wetlands in an actual policy setting of proposed groundwater transfers in Eastern Nevada. We illustrate how Bayesian estimation techniques can be used to overcome small sample problems notoriously present in Meta-functional Benefit Transfer. The highlights of our methodology are: (i) The hierarchical modeling of heteroskedasticity; (ii) The ability to incorporate additional information via refined priors; and (ii) The derivation of measures of model performance with the corresponding option of model-averaged Benefit Transfer predictions. Our results indicate that economic losses associated with the disappearance of these wetlands can be substantial and that primary valuation studies are warranted.      

Probabilistic Models for Bacterial Taxonomy

We give a survey of different partitioning methods that have been applied to bacterial taxonomy. We introduce a theoretical framework, which makes it possible to treat the various models in a unified way. The key concepts of our approach are prediction and storing of microbiological information in a Bayesian forecasting setting. We show that there is a close connection between classification and probabilistic identification and that, in fact, our approach ties these two concepts together in a coherent way.     

基于贝叶斯网络方法的客户忠诚研究

提高客户忠诚是企业的核心原则。在与传统的数据挖掘及决策分析方法比较的基础上,提出了用贝叶斯网络方法来对客户忠诚进行研究。用贝叶斯网络方法对客户数据进行分析,确定影响客户忠诚的各因素之间的贝叶斯网络结构,得出这些因素之间的相互决定关系,为采取有效措施提高客户忠诚提供了理论依据。     

Modeling Clustered Ordered Categorical Data: A Survey

This article surveys various strategies for modeling ordered categorical (ordinal) response variables when the data have some type of clustering, extending a similar survey for binary data by Pendergast, Gange, Newton, Lindstrom, Palta & Fisher (1996). An important special case is when repeated measurement occurs at various occasions for each subject, such as in longitudinal studies. A much greater variety of models and fitting methods are available than when a similar survey for repeated ordinal response data was prepared a decade ago (Agresti, 1989). The primary emphasis of the review is on two classes of models, marginal models for which effects are averaged over all clusters at particular levels of predictors, and cluster-specific models for which effects apply at the cluster level. We present the two types of models in the ordinal context, review the literature for each, and discuss connections between them. Then, we summarize some alternative modeling approaches and ways of estimating parameters, including a Bayesian approach. We also discuss applications and areas likely to be popular for future research, such as ways of handling missing data and ways of modeling agreement and evaluating the accuracy of diagnostic tests. Finally, we review the current availability of software for using the methods discussed in this article.     

A Generalized Cameron–Martin Formula with Applications to Partially Observed Dynamic Portfolio Optimization

The optimal dynamic allocation problem for a Bayesian investor is addressed when the stock's drift—modeled as a linear mean-reverting diffusion—is not observed directly but only via the measurement process. Adopting a martingale approach, an appropriate generalization of the Cameron–Martin (1945) formula then enables computation of both the optimal dynamic allocation and the value function for a general utility function, in terms of an inverse Laplace transform of an explicit expression. Moreover, closed-form formulas are provided in the case of power utility.     

How to Construct a Random Probability Measure

This article presents an overview of several constructive methods for generating random probability measures. Applications of random probability measures include Bayesian statistics, average optimal control problems, average error bounds for numerical equation solving methods, and models for random distributions of mass in space.     

The Logical Framework Approach–Millennium

The Logical Framework Approach (LFA) has proved to be a valuable tool for project approval, design, and evaluation. However, a few pitfalls make it hard to use within today's project management framework and to integrate with other project management tools. This article proposes an updated version of the LFA to improve its compatibility with today's corporate culture, project management framework, and tools. We propose to call the updated tool the Logical Framework Approach–Millennium (LFA‐M). The LFA‐M is a seven‐step approach leading to the development of the Logframe‐Millennium (LF‐M), a five‐column and four‐line matrix describing major project commitments and providing an overall understanding of the project. It was successfully implemented at the Canadian Space Agency and the Canadian Nuclear Safety Commission. The LFA‐M fits well within today's project management framework and corporate culture and leads easily to other project management tools.     

Methods for Default and Robust Bayesian Model Comparison: the Fractional Bayes Factor Approach

In the Bayesian approach to model selection and hypothesis testing, the Bayes factor plays a central role. However, the Bayes factor is very sensitive to prior distributions of parameters. This is a problem especially in the presence of weak prior information on the parameters of the models. The most radical consequence of this fact is that the Bayes factor is undetermined when improper priors are used. Nonetheless, extending the non-informative approach of Bayesian analysis to model selection/testing procedures is important both from a theoretical and an applied viewpoint. The need to develop automatic and robust methods for model comparison has led to the introduction of several alternative Bayes factors. In this paper we review one of these methods: the fractional Bayes factor (O'Hagan, 1995). We discuss general properties of the method, such as consistency and coherence. Furthermore, in addition to the original, essentially asymptotic justifications of the fractional Bayes factor, we provide further finite-sample motivations for its use. Connections and comparisons to other automatic methods are discussed and several issues of robustness with respect to priors and data are considered. Finally, we focus on some open problems in the fractional Bayes factor approach, and outline some possible answers and directions for future research.