Dirichlet models for square contingency tables

We consider the square contingency tables which arise when the same method of classification is applied twice. The hypothesis of marginal homogeneity is then relevant! and can be tested by various methods Models are discussed which contain marginal homogeneity as a special case. They include a class based on univariate and bivariate Dirichlet distributions. The question of ordered categories is briefly discussed. Applications are made to data on unaided distance vision.     

"化境"背后:钱钟书的文本价值论

钱钟书在讨论翻译问题时所采取的是观察家角度,他提出“化境”的本意并不在于为翻译行为设定唯一正确的标准;他认为翻译理论与翻译实践可以分离,翻译在目的语文化语境中起着重要作用。从钱钟书暗喻的文本价值论来看,可以推断出他对文本竞争和语言竞争的提倡。     

含未知输入的离散奇异系统的观测器设计

针对线性离散奇异系统研究了状态方程和测量方程均包含未知输入干扰的状态估计问题，在特定的假设条件下，通过系统输入-状态对的非奇异变换，把离散奇异系统等价地转化为常规状态空间系统的相应问题．然后用已知的方法设计常规状态空间系统的观测器，从而得到奇异系统的输入解耦观测器，并给出了这种观测器的存在条件．     

设计模式在网管系统中的设计与实现

将设计模式引入网管系统可以减少管理系统设计的复杂度,提高系统的开发效率。在分析设计模式中的Singleton模式、Adapter模式、Observer模式的基础上,讨论了体系结构,以及为设计模式如何实现网管系统功能做出了理论指导。通过分析证明在网管系统中运用设计模式是提高系统质量的有效途径。     

Category Distinguishability and Observer Agreement

It is common in the medical, biological, and social sciences for the categories into which an object is classified not to have a fully objective definition. Theoretically speaking the categories are therefore not completely distinguishable. The practical extent of their distinguishability can be measured when two expert observers classify the same sample of objects. It is shown, under reasonable assumptions, that the matrix of joint classification probabilities is quasi-symmetric, and that the symmetric matrix component is non-negative definite. The degree of distinguishability between two categories is defined and is used to give a measure of overall category distinguishability. It is argued that the kappa measure of observer agreement is unsatisfactory as a measure of overall category distinguishability.     

A Preliminary Examination of the Effects of Observer Presence on Work-Related Behavior in a Simulated Office

The current study evaluated the effects of prolonged observer presence on individuals' work-related behavior within sessions and across sessions. Participants were three undergraduate students who transcribed articles at a computer workstation in a simulated office setting. Overall, participants demonstrated increases and decreases in their work-related behavior in the presence of an observer. The demonstration of spontaneous recovery suggests that those decreases were due to fatigue, not habituation. Although limitations exist in the current study, this study represents an initial step toward examining behavioral habituation in humans to prolonged observer presence. Future researchers are encouraged to conduct analog studies with more participants, and various observer presence schedules, to determine whether performance changes to direct observation are habituation, fatigue, attention-related changes, or some other confound.     

Generalized Utilitarianism and Harsanyi's Impartial Observer Theorem

Harsanyi's impartial observer must consider two types of lotteries: imaginary identity lotteries (“accidents of birth”) that she faces as herself and the real outcome lotteries (“life chances”) to be faced by the individuals she imagines becoming. If we maintain a distinction between identity and outcome lotteries, then Harsanyi‐like axioms yield generalized utilitarianism, and allow us to accommodate concerns about different individuals' risk attitudes and concerns about fairness. Requiring an impartial observer to be indifferent as to which individual should face similar risks restricts her social welfare function, but still allows her to accommodate fairness. Requiring an impartial observer to be indifferent between identity and outcome lotteries, however, forces her to ignore both fairness and different risk attitudes, and yields a new axiomatization of Harsanyi's utilitarianism.     

Observing the Observer

Previous research has demonstrated that individuals improve their performance of a task after observing and evaluating others perform that task, a phenomenon known as the observer effect. Most of the research has demonstrated this when the observers were aware that their performance of the task was also being observed, suggesting that reactivity may play an important role. The current study examined this by evaluating the impact that observing others’ safety performance had on the observers’ subsequent safety performance under reactivity and nonreactivity conditions. Results suggest that the observer effect might be more robust when observers are aware that their performance is also being evaluated.     

Using Community Members to Collect Observational Data: Observer Training and Data Quality Assessment

ABSTRACT

This article highlights a structured approach to preparing community members for observational data collection in participatory research. Providing training related to the items that will be observed and conducting post-training assessments of observer accuracy and interrater reliability provides researchers with a measure of observer readiness to collect data. In addition, reassessing observer accuracy and interrater reliability at the end of data collection offers a measure of confidence in the data collection process. Discussion of this approach includes addressing survey items with low observer percentage agreement scores and training and evaluation strategies for intermittent and extended data collection periods.     

Behavior of agreement measures in the presence of zero cells and biased marginal distributions

Kappa and B assess agreement between two observers independently classifying N units into k categories. We study their behavior under zero cells in the contingency table and unbalanced asymmetric marginal distributions. Zero cells arise when a cross-classification is never endorsed by both observers; biased marginal distributions occur when some categories are preferred differently between the observers. Simulations studied the distributions of the unweighted and weighted statistics for k=4, under fixed proportions of diagonal agreement and different patterns off-diagonal, with various sample sizes, and under various zero cell count scenarios. Marginal distributions were first uniform and homogeneous, and then unbalanced asymmetric distributions. Results for unweighted kappa and B statistics were comparable to work of Muñoz and Bangdiwala, even with zero cells. A slight increased variation was observed as the sample size decreased. Weighted statistics did show greater variation as the number of zero cells increased, with weighted kappa increasing substantially more than weighted B. Under biased marginal distributions, weighted kappa with Cicchetti weights were higher than with squared weights. Both statistics for observer agreement behaved well under zero cells. The weighted B was less variable than the weighted kappa under similar circumstances and different weights. In general, B's performance and graphical interpretation make it preferable to kappa under the studied scenarios.