基于Gini指数的认知诊断计算机化自适应选题策略

Gini指数可用来描述分布的不均匀性,已广泛应用于决策树算法,本文开发了基于Gini指数的认知诊断计算机化自适应选题策略,并在饱和模型和缩减模型下与SHE, MPWKL,GDI,PWKL选题策略进行比较。模拟研究表明,基于Gini指数的选题策略与SHE,MPWKL,GDI相比,分类精度相近并提高了题库的利用率;与PWKL相比,提高了分类的精度和选题速度,综合来看,基于Gini指数的选题策略能够兼顾分类精度和题库使用均匀性。     

A Bayesian analysis of finite mixtures in the LISREL model

In this paper, we propose a Bayesian framework for estimating finite mixtures of the LISREL model. The basic idea in our analysis is to augment the observed data of the manifest variables with the latent variables and the allocation variables. The Gibbs sampler is implemented to obtain the Bayesian solution. Other associated statistical inferences, such as the direct estimation of the latent variables, establishment of a goodness-of-fit assessment for a posited model, Bayesian classification, residual and outlier analyses, are discussed. The methodology is illustrated with a simulation study and a real example.This research was supported by a Hong Kong UGC Earmarked grant CUHK 4026/97H. The authors are indebted to the Editor, the Associate Editor, and three anonymous reviewers for constructive comments in improving the paper, and also to ICPSR and the relevant funding agency for allowing the use of the data. The assistance of Michael K.H. Leung and Esther L.S. Tam is gratefully acknowledged.     

Principles Behind Definitions of Diseases – a Criticism of the Principle of Disease Mechanism and the Development of a Pragmatic Alternative

Many philosophers and medical scientists assume thatdisease categories or entities used to classify concrete cases ofdisease, are often defined by disease mechanisms or causalprocesses. Others suggest that diseases should always be definedin this manner. This paper discusses these standpoints criticallyand concludes that they are untenable, not only when `diseasemechanism' refers to an objective mechanism, but also when`mechanism' refers to a pragmatically demarcated part of thetotal ``objective' causal structure of diseases. As an alternativeto principles that use the concept of disease mechanism oranalogous concepts, a pragmatic approach is suggested anddescribed. This approach has been suggested before, but inproblematic or inadequate versions. This paper proposes a versioncompiled of two ``pragmatic principles' and shows that they aremuch more adequate than the principle of disease mechanism. Withreference to a case study of a still ongoing internationaldiscussion of various candidates for a classification system formalignant lymphomas, including REAL (Revised European–AmericanClassification of Lymphoid Neoplasms) in which the concept ofdisease mechanism or analogous concepts plays a very small part,it is shown just how pivotal these two pragmatic principles canbe in actual discussions of definitions of diseases. Finally, itis pointed out that with regard to modern philosophy of languageit may, at least in some cases, be problematic to distinguishbetween the two pragmatic principles as they stand.     

分类研究中的原型与样例观

该文具体分析了现代认知心理学对分类问题的主要看法,指出了当前分类研究范式存在的问题及今后进一步研究的主要方向。     

Ideal Point Discriminant Analysis Revisited with a Special Emphasis on Visualization

Ideal point discriminant analysis is a classification tool which uses highly intuitive multidimensional scaling procedures. However, in the last paper, Takane wrote about it. He concludes that the interpretation is rather intricate and calls that a weakness of the model. We summarize the conditions that provide an easy interpretation and show that in maximum dimensionality they can be obtained without any loss. For reduced dimensionality, it is conjectured that loss is minor which is examined using several data sets. This research was conducted while the author was sponsored by the Netherlands Organisation for Scientific Research (NWO), Innovational Grant, no. 452-06-002.     

Reasoning from Classifications and Definitions

In this paper we analyze the uses and misuses of argumentation schemes from verbal classification, and show how argument from definition supports argumentation based on argument from verbal classification. The inquiry has inevitably included the broader study of the concept of definition. The paper presents the schemes for argument from classification and for argument from definition, and shows how the latter type of argument so typically supports the former. The problem of analyzing arguments based on classification is framed in a structure that reveals the crucial role it plays in the persuasion process. The survey of the literature includes the work of Hastings, Perelman, Kienpointner and Schiappa, but still finds much of value in Aristotle. Lessons drawn from Aristotle’s Topics are shown to be useful for developing new tools for assessing definitions and arguments from definition.

Response bias in judging deceptive movements

Two not mutually exclusive explanations, perceptual and motor expertise, account for the finding that experts outperform novices in recognizing deceptive actions from bodily (kinematic) cues. The aim of the present study was twofold: First, we sought to examine the impact of motor and perceptual expertise on distinguishing deceptive and non-deceptive actions. Second, we tested the hypothesis that differences in perceptual judgments on deceptive movements vs. non-deceptive movements do not necessarily need to be caused by either perceptual or motor expertise differences, but can also be a result of response bias. Skilled handball players (field players and goalkeepers) and novices had to detect whether a penalty-taker shot or faked a shot at the goal. Signal detection theory (SDT) analysis revealed that skilled handball players outperformed novices in discriminating shots from fakes. No differences in perceptual sensitivity were found between the goalkeepers and the field players. However, SDT analysis showed that goalkeepers were significantly biased to judge movements as deceptive, while neither field players nor novices showed this response bias.     

Haptic mental rotation revisited: multiple reference frame dependence

The nature of reference frames involved in haptic spatial processing was addressed by means of a haptic mental rotation task. Participants assessed the parity of two objects located in various spatial locations by exploring them with different hand orientations. The resulting response times were fitted with a triangle wave function. Phase shifts were found to depend on the relation between the hands and the objects, and between the objects and the body. We rejected the possibility that a single reference frame drives spatial processing. Instead, we found evidence of multiple interacting reference frames with the hand-centered reference frame playing the dominant role. We propose that a weighted average of the allocentric, the hand-centered and the body-centered reference frames influences the haptic encoding of spatial information. In addition, we showed that previous results can be reinterpreted within the framework of multiple reference frames. This mechanism has proved to be ubiquitously present in haptic spatial processing.     

胸椎管狭窄症的临床分型与术式选择

为探讨胸椎管狭窄症的临床分型与术式选择,对35例患者行后路椎管减压术,所有患者术后12个月时ASIA分级均有1级或1级以上的恢复;按Epstein标准：优良率：85．7％;影像学检查示脊髓减压充分,植骨患者术后6个月均达骨性融合。据不同的临床类型选择不同的术式,可取得满意的临床疗效。