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991.
The authors consider general estimators for the mean and variance parameters in the random effect model and in the transformation model for data with multiple levels of variation. They show that these estimators have different distributions under the two models unless all the variables have Gaussian distributions. They investigate the asymptotic properties of bootstrap procedures designed for the two models. They also report simulation results and illustrate the bootstraps using data on red spruce trees. 相似文献
992.
993.
Sarah Fenstermaker 《Journal of Family and Economic Issues》1996,17(3-4):231-243
In this article, earlier work on the organization of the household day is revisited to bring a sociological perspective to the study of household time. There is much to be gained from elaborating the conceptualization and measurement of time use to acknowledge and the employment of its dynamic qualities and meanings. That is, analysis of household time use must become far more than a longitudinal accounting process. In this article, no roadmap to such a destination can be provided but perhaps movement in a new direction. The practical application of insights from research on household time use requires conceptual frameworks that allow household time to be depicted as it unfolds and as participants experience it. That is, serious attention might be lent not only to studying where time is spent but also to how activities are situated and experienced in time to realize human affairs.She is the author ofThe Gender Factory: The Apportionment of Work in American Households, and in 1995 she coeditedindividual Voices, Collective Visions: 50 Years of Women in Sociology, published by Temple University Press. Her current work focuses on the theoretical articulation of race, class and gender in women's work.This paper required a good deal of reflection on a project I undertook with Richard A. Berk in 1975. I am grateful for his comments and suggestions. 相似文献
994.
Most studies of burnout have focused on lack of resources, prevalence of burnout, and negative outcomes. In contrast, this study examined the relationships among altruism, burnout and a positive outcome, namely, the engagement in organizational citizenship behaviour. Web questionnaires were distributed to employees in three professional organizations. The results from the 178 respondents indicated that altruism is related to organizational citizenship behaviour. Of the three dimensions of burnout, only reduced personal accomplishment was (negatively) associated with engagement in organizational citizenship behaviours. Implications of the results are discussed and directions for future research are offered. 相似文献
995.
This paper examines modeling and inference questions for experiments in which different subsets of a set of k possibly dependent components are tested in r different environments. In each environment, the failure times of the set of components on test is assumed to be governed by a particular type of multivariate exponential (MVE) distribution. For any given component tested in several environments, it is assumed that its marginal failure rate varies from one environment to another via a change of scale between the environments, resulting in a joint MVE model which links in a natural way the applicable MVE distributions describing component behavior in each fixed environment. This study thus extends the work of Proschan and Sullo (1976) to multiple environments and the work of Kvam and Samaniego (1993) to dependent data. The problem of estimating model parameters via the method of maximum likelihood is examined in detail. First, necessary and sufficient conditions for the identifiability of model parameters are established. We then treat the derivation of the MLE via a numerically-augmented application of the EM algorithm. The feasibility of the estimation method is demonstrated in an example in which the likelihood ratio test of the hypothesis of equal component failure rates within any given environment is carried out. 相似文献
996.
997.
We present a method for estimating transmission matrices that describe the mixing and the probability of infection between age groups. Transmission matrices can be used to estimate age-dependent forces of infection in age-structured, compartmental models for the study of infectious diseases. We analyze the social network generated by the synthetic population of Portland and extract mixing patterns. Our results show that the mixing within the population consists of two groups, children and adults. Children interact most frequently with other children close to their own age, while adults interact with a wider range of age groups and the durations of typical adult contacts are shorter than typical contacts between children. Furthermore, the transmission matrix shows that children are more likely to acquire infection than adults. 相似文献
998.
999.
Björn Häckel 《Zeitschrift für Betriebswirtschaft》2008,78(9):969-977
Die Forderung nach schwacher Wertadditivit?t von Sicherheits?quivalenten ist in Abh?ngigkeit des jeweiligen Bewertungszwecks
zu diskutieren. W?hrend in der unternehmensexternen Bewertungssicht, z.B. bei der Unternehmensbewertung, die Forderung nach
schwacher Wertadditivit?t gut begründbar ist, stellt sie im Bereich der unternehmensinternen Steuerungssicht eine „Nice to
have“-Anforderung dar. Darüber hinaus werden in der bisherigen Literatur zur Anwendbarkeit von Sicherheits?quivalenten die
Kernherausforderungen der unternehmensinternen Steuerung vernachl?ssigt. Insbesondere die ad?quate Berücksichtigung stochastischer
Abh?ngigkeiten im Portfolioverbund bei der Bewertung von Einzelgesch?ften mittels Sicherheits?quivalenten stellt eine Forschungslücke
dar. 相似文献
1000.