Determining Differences in Expert Judgment: Implications for Knowledge Acquisition and Validation*

In knowledge acquisition, it is often desirable to aggregate the judgments of multiple experts into a single system. In some cases this takes the form of averaging the judgments of those experts. In these situations it is desirable to determine if the experts have different views of the world before their individual judgments are aggregated. In validation, multiple experts often are employed to compare the performance of expert systems and other human actors. Often those judgments are then averaged to establish performance quality of the expert system. An important part of the comparison process should be determining if the experts have a similar view of the world. If the experts do not have similar views, their evaluations of performance may differ, resulting in a meaningless average performance measure. Alternatively, if all the validating experts do have similar views of the world then the validation process may result in paradigm myopia.     

国际原子能机构及其核查效能研究——以该机构在中东核查为例

国际原子能机构自1957年成立以来,经历了产生、发展和完善三个阶段,其核查效能也处于动态变化之中.影响国际原子能机构核查效能有三个基本因素:该机构核查制度的完善程度、大国对该机构的支持度和受核查国融入国际体系的程度.为检验上述基本假设,本文考察了国际原子能机构在中东国家的核查实践,分析了其对以色列、伊拉克、利比亚和伊朗四国核查是否有效及其原因,最终证明上述假设基本成立.     

岑参赴安西路途考证

唐代著名诗人岑参以边塞诗名世,从文学史的角度结合岑参诗作描述岑参西域经历的论述颇多,但分歧亦大,尤以首赴安西路途为最。运用当今学界对唐代西域之政治、军事、商贸、地理、交通及出土文物的研究成果,基本可以说明,岑参首途安西出瓜州后,按常理应该不走丝路南道,不到敦煌,亦不过阳关,而是径由玉门关,走最安全、通畅之丝路中道。     

Comparing accuracies of two screening tests in a two-phase study for dementia

A two-phase design has been widely used in epidemiological studies of dementia. The first phase assesses a large sample with screening tests. The second, based on the screening test results and possibly on other observed patient's factors, selects a subset of the study sample for a more definitive disease verification assessment. In comparing the accuracies of two screening tests in a two-phase study of dementia, inferences are commonly made from a sample of verified cases. The omission of non-verified cases can seriously bias comparison results. To correct for this bias, we derive the maximum likelihood (ML) estimators for the accuracies of two screening tests and their corresponding correlation. The p -values and confidence intervals are computed using the asymptotic normality of the ML estimators. Our method is used to compare the accuracies of two screening tests in a two-phase epidemiological study of dementia. We found that, although the sensitivities of the new and standard screening tests in detecting a diseased subject are not different, the new screening test performs better in detecting a non-diseased subject.     

对新型生育文化效应的实证分析

新型生育文化是一种与传统生育文化既有联系又有根本区别的现代生育文化 ,它的效应的产生和发挥对人口与社会经济发展具有十分突出的意义。本文对我国新型生育文化效应发挥情况进行了初步的实证研究 ,主要涉及到新型生育文化效应的指标设置、运用、问卷调查分析以及促进效应有效发挥的模式特征。     

徐铉及其小说《稽神录》

由《稽神录》可以看出徐铉的思想性格 :徐铉的忠直个性是他早期仕途坎坷的原因 ,入宋后 ,表面上颇受信用 ,实际上是宋太祖、太宗的猜忌对象。他虽“好鬼神” ,却并不排斥释氏 ,又具儒者的悲悯情怀。《稽神录》文本价值虽不甚高 ,对有宋一代的小说却产生了很大的影响 ,这是一种非文本的影响。     

盈余质量对自愿性信息披露的影响及作用机理

自愿性信息披露是管理层对外传递公司价值,缓解信息不对称的重要手段,是强制性财务报告的有益补充。财务报告的盈余信息不但通过契约制定约束了管理层行为,其盈余质量也反映了管理层可信度并影响自愿披露的估值作用,这些都会影响公司自愿披露行为。本文以上市公司自愿披露的前瞻性信息为对象,分析了盈余质量对自愿性信息披露的影响及作用机理。实证结果证实了盈余质量对自愿性信息披露有契约作用和鉴证作用;契约作用表现为盈余质量可通过降低代理成本提高自愿披露水平;而鉴证作用体现在盈余质量为自愿披露信息提供了可鉴证性保障,提高了公司价值与自愿披露水平的相关性。     

Testing for the maximum mean in a mixture of normals

We consider the test of the null hypothesis that the largest mean in a mixture of an unknown number of normal components is less than or equal to a given threshold. This test is motivated by the problem of assessing whether the Soviet Union has been operating in compliance with the Nuclear Test Ban Treaty. In our analysis, the number of normal components is determined using Akaike's Information Criterion while the hypothesis test itself is based on asymptotic results given by Behboodian for a mixture of two normal components. A bootstrap approach is also considered for estimating the standard error of the largest estimated mean. The performance of the testa are examined through the use of simulation.     

The Effect of Verification Bias in the Naïve Estimators of Accuracy of a Binary Diagnostic Test

The assessment of a binary diagnostic test requires a knowledge of the disease status of all the patients in the sample through the application of a gold standard. In practice, the gold standard is not always applied to all of the patients, which leads to the problem of partial verification of the disease. When the accuracy of the diagnostic test is assessed using only those patients whose disease status has been verified using the gold standard, the estimators obtained in this way, known as Naïve estimators, may be biased. In this study, we obtain the explicit expressions of the bias of the Naïve estimators of sensitivity and specificity of a binary diagnostic test. We also carry out simulation experiments in order to study the effect of the verification probabilities on the Naïve estimators of sensitivity and specificity.     

20世纪《花间集》研究的回顾与反思

《花间集》是我国词史上第一部文人词总集。自它问世迄今的一千余年间,前贤时人对之展开了广泛的研究,并且取得了许多令人瞩目的成果。20世纪以来,围绕《花间集》和“花间”词人群体的研究,与前代相比呈现出新的特征与走向,本文主要从词集校注评译、作家生平考证、作品艺术风格等几个方面对百年《花间集》研究进行了考察,并加以回顾与反思。