Adaptive designs for single‐arm phase II trials in oncology

Clinical phase II trials in oncology are conducted to determine whether the activity of a new anticancer treatment is promising enough to merit further investigation. Two‐stage designs are commonly used for this situation to allow for early termination. Designs proposed in the literature so far have the common drawback that the sample sizes for the two stages have to be specified in the protocol and have to be adhered to strictly during the course of the trial. As a consequence, designs that allow a higher extent of flexibility are desirable. In this article, we propose a new adaptive method that allows an arbitrary modification of the sample size of the second stage using the results of the interim analysis or external information while controlling the type I error rate. If the sample size is not changed during the trial, the proposed design shows very similar characteristics to the optimal two‐stage design proposed by Chang et al. (Biometrics 1987; 43:865–874). However, the new design allows the use of mid‐course information for the planning of the second stage, thus meeting practical requirements when performing clinical phase II trials in oncology. Copyright © 2012 John Wiley & Sons, Ltd.     

论“被现代”图景在现代中国文学中的展现

"现代"是由各种向不同方向扯动的诸多主题共同建构的一种历史凝缩的结果。"现代"是背靠启蒙运动和工业革命的社会进程。它的发展将整个世界卷入其中。它同时拥有积极阳光的一面和腐烂阴暗的一面。后者集中体现在那些没有两大背景的"被现代"的第三世界国家。现代中国就是不幸处于现代时空中的第三世界国家。在现代中国文学中,我们能够看到"被现代"所带来的无奈与衰颓。老舍的《骆驼祥子》就是展现这幅"被现代"图景的典型作品之一。     

Symmetrical design for symmetrical global sensitivity analysis of model output

Symmetrical global sensitivity analysis (SGSA) can help practitioners focusing on the symmetrical terms of inputs whose uncertainties have an impact on the model output, which allows reducing the complexity of the model. However, there remains the challenging problem of finding an efficient method to get symmetrical global sensitivity indices (SGSI) when the functional form of the symmetrical terms is unknown, including numerical and non-parametric situations. In this study, we propose a novel sampling plan, called symmetrical design, for SGSA. As a preliminary experiment for model feature extracting, such plan offers the virtue of run-size economy due to its closure respective to the given group. Using the design, we give estimation methods of SGSI as well as their asymptotic properties respectively for numerical model and non-parametrical model directly by the model outputs, and further propose a significance test for SGSI in non-parametric situation. A case study for a benchmark of GSA and a real data analysis show the effectiveness of the proposed design.     

服装系列设计方法之“抽象方程”论

通过长期的实践教学经验总结,将服装系列设计方法与数学方程联系在一起,形成服装系列设计的"抽象方程"理论,使服装系列设计具有了定向、定量、明确、有序的特征,力求寻找一条由简到繁、由易到难、循序渐进的学习实践方法,帮助服装设计初学者尽早摆脱设计瓶颈,步入设计正轨。     

Bayesian optimal sequential design for nonparametric regression via inhomogeneous evolutionary MCMC

We develop a novel computational methodology for Bayesian optimal sequential design for nonparametric regression. This computational methodology, that we call inhomogeneous evolutionary Markov chain Monte Carlo, combines ideas of simulated annealing, genetic or evolutionary algorithms, and Markov chain Monte Carlo. Our framework allows optimality criteria with general utility functions and general classes of priors for the underlying regression function. We illustrate the usefulness of our novel methodology with applications to experimental design for nonparametric function estimation using Gaussian process priors and free-knot cubic splines priors.     

近代城市空间改造的时空进程

近代城市人口的增长、城市职能的变化、市政机构的出现带来了城市空间的转变。２０世纪初，中国开始了大范围的城市基础设施改造与新建。其中最有代表性的是拆城、填濠、修筑环城马路的工程，此后全国大部分的城市改造都遵循了相似的模式。本文通过对近１２００座治所城市城墙变动信息的研究发现，２０世纪大规模的城市空间改造最初主要从东南沿海省份开始，３０年代末至４０年代的战争打破了这一过程，但随着新中国成立后城市建设的恢复，空间改造的进程继续向西部省份推进，总体上呈现由东向西，由中心向边缘发展的特点。     

Finding Bhaskar in all the wrong places? Causation,process, and structure in Bhaskar and Deleuze

This article examines the reception of Roy Bhaskar amongst some contemporary Deleuzians. It proceeds by rejecting the all too often predilection of opposing realism to ‘postmodernism’ or ‘post‐structuralism’ arguing instead for the need to bring one into dialogue with the other. To this end, the paper explores the resonances and points of departure between the work of Gilles Deleuze and Roy Bhaskar. In particular, it examines the language of causation, object‐oriented versus process‐oriented ontologies, as well as the charge by Deleuzians that Bhaskar is an essentialist. Through this engagement it attempts to develop and rethink explanation and causation in terms of a more chaotic ontology of machines, centered around the concept of structure, process, and production in an open, heterogeneous, and dynamic world. The end result is a more chaotic concept of realism.     

期待“全考古学”时代的到来——兼评《牛河梁红山文化遗址建筑设计思想研究》

由于考古学产生约两百年来一直被定义为研究“物质遗存”，同时又缺乏探讨遗迹、器物纹饰内涵的理论与方法，导致考古学在基本理论、方法上与其目标追求长期陷入困境与悖论，而浩如烟海的纹饰及一些遗迹的内涵始终处于考古学的边缘不得解读。故基本教义的考古学从理论、方法到实践都是残缺不全的。因此提出“全考古学”概念，主张将考古学研究的对象定义为“文化遗存”，同时将考古学研究划分为三个阶段：第一阶段“田野考古”及资料整理；第二阶段“室内考古”即读懂材料；第三阶段，探究社会历史发展规律等。“全考古学”在研究方法上是全方位的、立体交叉式的；当前，我们应该大力倡导和支持“全考古学”研究。董婕、朱成杰著《牛河梁红山文化遗址建筑设计思想研究》正是“全考古学”第二阶段的典型作品。     

A Semiparametric Regression Model for Longitudinal Data with Non‐stationary Errors

Motivated by the need to analyze the National Longitudinal Surveys data, we propose a new semiparametric longitudinal mean‐covariance model in which the effects on dependent variable of some explanatory variables are linear and others are non‐linear, while the within‐subject correlations are modelled by a non‐stationary autoregressive error structure. We develop an estimation machinery based on least squares technique by approximating non‐parametric functions via B‐spline expansions and establish the asymptotic normality of parametric estimators as well as the rate of convergence for the non‐parametric estimators. We further advocate a new model selection strategy in the varying‐coefficient model framework, for distinguishing whether a component is significant and subsequently whether it is linear or non‐linear. Besides, the proposed method can also be employed for identifying the true order of lagged terms consistently. Monte Carlo studies are conducted to examine the finite sample performance of our approach, and an application of real data is also illustrated.     

A revisit to test the equality of variances of several populations

We revisit the problem of testing homoscedasticity (or, equality of variances) of several normal populations which has applications in many statistical analyses, including design of experiments. The standard text books and widely used statistical packages propose a few popular tests including Bartlett's test, Levene's test and a few adjustments of the latter. Apparently, the popularity of these tests have been based on limited simulation study carried out a few decades ago. The traditional tests, including the classical likelihood ratio test (LRT), are asymptotic in nature, and hence do not perform well for small sample sizes. In this paper we propose a simple parametric bootstrap (PB) modification of the LRT, and compare it against the other popular tests as well as their PB versions in terms of size and power. Our comprehensive simulation study bursts some popularly held myths about the commonly used tests and sheds some new light on this important problem. Though most popular statistical software/packages suggest using Bartlette's test, Levene's test, or modified Levene's test among a few others, our extensive simulation study, carried out under both the normal model as well as several non-normal models clearly shows that a PB version of the modified Levene's test (which does not use the F-distribution cut-off point as its critical value), and Loh's exact test are the “best” performers in terms of overall size as well as power.