Obtrusiveness as Strategy in Ethnographic Research

Qualitative Sociology - Unlocking the Iron Cage, Michael Schwalbe's 1996 ethnography of the men's movement, is in many ways a classic ethnographic account, involving almost three years of...     

A Comparison of Frailty and Other Models for Bivariate Survival Data

Multivariate survival data arise when eachstudy subject may experience multiple events or when study subjectsare clustered into groups. Statistical analyses of such dataneed to account for the intra-cluster dependence through appropriatemodeling. Frailty models are the most popular for such failuretime data. However, there are other approaches which model thedependence structure directly. In this article, we compare thefrailty models for bivariate data with the models based on bivariateexponential and Weibull distributions. Bayesian methods providea convenient paradigm for comparing the two sets of models weconsider. Our techniques are illustrated using two examples.One simulated example demonstrates model choice methods developedin this paper and the other example, based on a practical dataset of onset of blindness among patients with diabetic Retinopathy,considers Bayesian inference using different models.     

饭店收入资本化估价方法应用分析

随着饭店市场竞争加剧,饭店并购日益增加,由此带来饭店估价问题。各国估价机构先后提出一系列估价方法,为饭店交易提供定价依据。近年来,我国饭店业开始面临这个问题,如何合理地评估饭店价格成为交易各方关注的焦点。在介绍国外传统饭店估价方法的基础上,重点介绍基于企业实体的收入资本化估价方法,并从多个角度对这些方法进行综合评价,试图为我国饭店估价提供一种新的思路。     

关于大学生思想品德教育实施方法的评价

如何把握和正确运用思想品德教育的方法 ,在思想品德教育工作中具有重要地位。本文仅就大学生思想品德教育实施的 10种方法的评价指标问题谈谈看法     

合作学习法在英语教学中的应用

合作学习是学生提高自主学习能力的必经阶段和重要手段。本文从运用合作学习的理论依据、合作学习的实施、实施过程中出现的问题和解决途径以及在合作学习过程中对教师的要求等方面进行了分析和探讨。     

Statistical Issues in Weather Forecasting*

Research and operational applications in weather forecasting are reviewed, with emphasis on statistical issues. It is argued that the deterministic approach has dominated in weather forecasting, although weather forecasting is a probabilistic problem by nature. The reason has been the successful application of numerical weather prediction techniques over the 50 years since the introduction of computers. A gradual change towards utilization of more probabilistic methods has occurred over the last decade; in particular meteorological data assimilation, ensemble forecasting and post‐processing of model output have been influenced by ideas from statistics and control theory.     

试析影响英语听力提高的因素及训练方法

分析了影响英语听力的语音、词汇、习语、发音四个因素,明确了听力训练的有恒、有序、有量的三原则,介绍了听力速度训练的“循序渐进法”、“轰炸法”的两种方法,科学安排听力训练的入门、初级、中级、高级四个阶段的具体训练内容与方法。     

诗须要用具体的做法——胡适新诗写作的美学追求及其影响

“诗须要用具体的做法”是胡适在新诗的初创时期提出的一个新诗写作的纲领性美学主张。这一主张的形成,既缘自于胡适对于白话新诗写作中所出现的现实问题的敏感,同时又与他业已形成的中西诗歌经验背景密切相关。它的内涵虽难于确切认指,但仔细分梳,却自有其意义流向。其从正负两个方面对于胡适和整个新诗写作给予了十分重要的影响。     

A Baseline-free Procedure for Transformation Models Under Interval Censorship

An important property of Cox regression model is that the estimation of regression parameters using the partial likelihood procedure does not depend on its baseline survival function. We call such a procedure baseline-free. Using marginal likelihood, we show that an baseline-free procedure can be derived for a class of general transformation models under interval censoring framework. The baseline-free procedure results a simplified and stable computation algorithm for some complicated and important semiparametric models, such as frailty models and heteroscedastic hazard/rank regression models, where the estimation procedures so far available involve estimation of the infinite dimensional baseline function. A detailed computational algorithm using Markov Chain Monte Carlo stochastic approximation is presented. The proposed procedure is demonstrated through extensive simulation studies, showing the validity of asymptotic consistency and normality. We also illustrate the procedure with a real data set from a study of breast cancer. A heuristic argument showing that the score function is a mean zero martingale is provided.     

Portfolio optimization: New capabilities and future methods

Summary  This paper addresses the problem of portfolio selection in finance. In many cases, currently available software to compute the efficient frontier runs into difficulty in problems with more than about 600 securities. To proceed beyond this size, it is often necessary to modify the problem in which case there is typically a loss of information. In this paper, we discuss a computer capability that can exactly compute mean-variance efficient frontiers of problems with up to 2,000 securities in very reasonable time (even if a problem’s covariance matrix is 100% dense). The paper also discusses an augmentation to the theory of portfolio selection that allows multiple objectives (such as dividends, liquidity, social responsibility, amount invested in R&D, and so forth) to be incorporated into the portfolio selection process. In such problems, the efficient set is no longer a “frontier,” but is now best described as a “surface” with the interesting property that it is composed of platelets (like on the back of a turtle). Moreover, the computer capability that can compute the exact efficient frontier of a mean-variance problem with up to 2,000 securities also has, after additional coding, the ability to compute exactly all platelets of the efficient surface of a tri-criterion portfolio problem with up to 400 securities.

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Zusammenfassung  In dieser Arbeit stellen wir einen leistungsf?higen Rechenalgorithmus vor, um den effizienten Rand (die nichtdominierten Alternativen) von Portfolio-Auswahlproblemen in der Finanzierung zu bestimmen. Wir bezeichnen den Berechnungsalgorithmus, der in Java programmiert ist, mit MPQ (multi-parametric quadratic programming). MPQ weist gegenüber bisherigen Berechnungsverfahren eine Reihe von Vorteilen auf: Es kann für umfangreiche Anwendungsf?lle genutzt werden, ist durch passable Rechenzeiten charakterisiert und kann die Menge effizienter Alternativen in einem Bruchteil bisher üblicher Rechenzeiten bestimmen.