Joint Modelling of Survival and Longitudinal Data with Informative Observation Times

In this paper, we consider the joint modelling of survival and longitudinal data with informative observation time points. The survival model and the longitudinal model are linked via random effects, for which no distribution assumption is required under our estimation approach. The estimator is shown to be consistent and asymptotically normal. The proposed estimator and its estimated covariance matrix can be easily calculated. Simulation studies and an application to a primary biliary cirrhosis study are also provided.     

A class of partially linear transformation models for recurrent gap times

In this article, we propose a general class of partially linear transformation models for recurrent gap time data, which extends the linear transformation models by incorporating non linear covariate effects and includes the partially linear proportional hazards and the partially linear proportional odds models as special cases. Both global and local estimating equations are developed to estimate the parametric and non parametric covariate effects, and the asymptotic properties of the resulting estimators are established. The finite-sample behavior of the proposed estimators is evaluated through simulation studies, and an application to a clinic study on chronic granulomatous disease is provided.     

Statistical considerations in clinical trial design with event-free survival as the primary efficacy endpoint

In late-phase confirmatory clinical trials in the oncology field, time-to-event (TTE) endpoints are commonly used as primary endpoints for establishing the efficacy of investigational therapies. Among these TTE endpoints, overall survival (OS) is always considered as the gold standard. However, OS data can take years to mature, and its use for measurement of efficacy can be confounded by the use of post-treatment rescue therapies or supportive care. Therefore, to accelerate the development process and better characterize the treatment effect of new investigational therapies, other TTE endpoints such as progression-free survival and event-free survival (EFS) are applied as primary efficacy endpoints in some confirmatory trials, either as a surrogate for OS or as a direct measure of clinical benefits. For evaluating novel treatments for acute myeloid leukemia, EFS has been gradually recognized as a direct measure of clinical benefits. However, the application of an EFS endpoint is still controversial mainly due to the debate surrounding definition of treatment failure (TF) events. In this article, we investigate the EFS endpoint with the most conservative definition for the timing of TF, which is Day 1 since randomization. Specifically, the corresponding non-proportional hazard pattern of the EFS endpoint is investigated with both analytical and numerical approaches.     

A multiple warm standby δ-shock system with a repairman having multiple vacations

In this article, a warm standby n-unit system is studied. The system is operational as long as there is one unit normal. The unit online, which has a lifetime distribution governed by a phase-type distribution, is also attacked by a shock from some external causes. Assume that shocks arrive according to a Poisson process. Whenever an interarrival time of shock is less than a threshold, the unit online fails. The lifetimes of the units in warm standby is exponentially distributed. A repairman who can take multiple vacations repairs the failed units based on the “first-in-first-out” rule. The repair times and the vacation times of repairman are governed by different phase-type distributions. For this system, the Markov process governing the system is constructed. The system is studied in a transient and stationary regime; the availability, the reliability, the rates of occurrence of the different types of failures, and the working probability of the repairman are calculated. A numerical application is performed to illustrate the calculations.     

“重陆轻海”与“通洋裕国”之海洋观刍议

明清两朝正处于世界性海洋历史发展的"千古变局"时代,但统治者沿袭传统模式,在立国思想上"重农抑商"、"重陆轻海",在国防战略上以"禁海"代替海防,禁海迁界、"守土防御",反映其海洋观念的淡薄;而东南沿海地方官员,尤其郑成功"通洋裕国"思想的提出和实践,显露出"以商立国",向海洋空间发展的意涵;传统时代"重陆轻海"与"通洋裕国"所反映的海洋观念,对国家民族发展的影响在某种程度上可以忽略不计,但大航海时代,海洋作为人类的第二生存空间影响到世界历史走向和发展格局时,"重陆轻海"观念所带来的深层影响会因此而改变国家和民族的命运。     

On the α-risks for shewhart control charts

The performance of the usual Shewhart control charts for monitoring process means and variation can be greatly affected by nonnormal data or subgroups that are correlated. Define the α_k-risk for a Shewhart chart to be the probability that at least one “out-of-control” subgroup occurs in k subgroups when the control limits are calculated from the k subgroups. Simulation results show that the α_k-risks can be quite large even for a process with normally distributed, independent subgroups. When the data are nonnormal, it is shown that the α_k-risk increases dramatically. A method is also developed for simulating an “in-control” process with correlated subgroups from an autoregressive model. Simulations with this model indicate marked changes in the α_k-risks for the Shewhart charts utilizing this type of correlated process data. Therefore, in practice a process should be investigated thoroughly regarding whether or not it is generating normal, independent data before out-of-control points on the control charts are interpreted to be due to some real assignable cause.     

浅论近代青海女性社会地位变迁及其原因

近代是青海女性社会地位发生变迁的时期,本文从女性形体观的转变、女性教育等方面,论述了近代青海女性社会地位的变迁及其原因。     

民国的风俗变革与变革风俗

民国时期是时代大发展、社会大变革的时期 ,风俗的演进也进入到转型的阶段。风俗的全面变革促使了一系列变革风俗的产生。文章论述了当时风俗文化演进的三种趋势———对人的尊重、对迷信的涤荡以及政治因素的渗入 ,是民国风俗步入现代化进程的显著标志     

怒俅殖边:近代云南一次意义深远的边疆开发

民国初期 ,云南地方政府在滇西北怒江少数民族地区的设治经营 ,是云南边疆民族地区发展历史上的一个重大事件 ,它对怒江地区的社会发展和各民族的进步产生了极其重大而深远的影响。本文阐述了“怒俅殖边”这一历史进程 ,认为它使怒江地区的民族关系得到明显的调整与改善 ;使怒江经济社会发展进入一个新时期 ;遏制了英国侵略势头 ,对巩固滇西北边防产生了重要和深远的影响