医疗需求与中国医疗费用增长——基于城乡老年医疗支出差异的视角

在人口老龄化和老年医疗支出城乡差异凸显的背景下,中国医疗费用增长部分源于合理的健康需求。利用中国营养与健康调查1991—2011年的八轮数据,构造出生组跟踪样本,分别考察城乡居民医疗支出的年龄效应,估算城乡老年医疗需求导致的费用上涨,可以发现:城市居民的人均医疗支出随年龄显著增加,但农村居民的人均医疗支出随年龄增长的趋势并不明显。而忽略出生组效应,会低估城乡老年医疗支出的差距。城乡老年医疗支出差距缩小,将导致医疗费用在2010—2030年年均实际增长约5.2%。在控制医疗总费用上涨的同时,医疗保险制度需根据老年医疗需求,调整医疗资源配置结构。     

Testing equality of two normal covariance matrices with monotone missing data

Abstract

The problem of testing equality of two multivariate normal covariance matrices is considered. Assuming that the incomplete data are of monotone pattern, a quantity similar to the Likelihood Ratio Test Statistic is proposed. A satisfactory approximation to the distribution of the quantity is derived. Hypothesis testing based on the approximate distribution is outlined. The merits of the test are investigated using Monte Carlo simulation. Monte Carlo studies indicate that the test is very satisfactory even for moderately small samples. The proposed methods are illustrated using an example.     

基于评价理论的APEC领导人宣言分析

2005年到2014年的APEC领导人宣言中的评价资源以借言为主，正面评价突出，其中鉴赏资源丰富，语势较强，立场分明。这些既体现出对话的和谐，又表明了领导人的决心和信心。2014年的领导人宣言的特点是亚太国家成果众多且认可度更高，特别鼓励区域内，以及政府与私营企业的战略性合作。     

国外城市机场噪声治理的多元路径及其启示

20世纪80年代以来,随着中国城市发展速度的持续提升,各级各类城市机场的建设步伐也不断加快,时至今日,机场已经成为了许多城市重要的对外交通枢纽和新的城市商业中心。但以噪声污染为重要表征的负外部性输出,在中国城市机场也呈现出蔓延之势。文章通过相关文献资料梳理发现,国外对城市机场噪声的治理一般通过机场规划、降噪技术、噪声征税、制度规制、强化绿化等多种路径展开。了解国外治理城市机场噪声的实践探索,对于我们寻求中国城市机场噪声治理的未来道路,具有重要的启示和借鉴意义。     

Reducing sample size needed for cox-proportional hazards model analysis using more efficient sampling method

Abstract

In general, survival data are time-to-event data, such as time to death, time to appearance of a tumor, or time to recurrence of a disease. Models for survival data have frequently been based on the proportional hazards model, proposed by Cox. The Cox model has intensive application in the field of social, medical, behavioral and public health sciences. In this paper we propose a more efficient sampling method of recruiting subjects for survival analysis. We propose using a Moving Extreme Ranked Set Sampling (MERSS) scheme with ranking based on an easy-to-evaluate baseline auxiliary variable known to be associated with survival time. This paper demonstrates that this approach provides a more powerful testing procedure as well as a more efficient estimate of hazard ratio than that based on simple random sampling (SRS). Theoretical derivation and simulation studies are provided. The Iowa 65+ Rural study data are used to illustrate the methods developed in this paper.     

The disembedded digital economy: Social protection for new economy employment in China

This research focuses upon employment in the new economy, exploring labour protection and social protection in the digital age in China. Through an empirical survey conducted in three Chinese cities, social insurance and the labour rights of employees in the digital economic sector, such as gig employment, e-commerce, and various other forms of online employment, have been examined in-depth. This study reveals new regulatory loopholes in the digital labour market, which have substantially eroded the basis of social policy arrangements in China, “softening” participation in social insurance branches and compliance with labour regulations remarkably. Drawing upon the theoretical concepts of Polanyi on embeddedness and disembeddedness, we argue that the digital employment sector in China has been increasingly disembedded from social institutions and social control. The new configuration in the digital field of social policy requires novel conceptual models and institutional settings to cope with increasing social risks in virtual spaces.     

A New Methodology for Before–After Safety Assessment Using Survival Analysis and Longitudinal Data

The widely used empirical Bayes (EB) and full Bayes (FB) methods for before–after safety assessment are sometimes limited because of the extensive data needs from additional reference sites. To address this issue, this study proposes a novel before–after safety evaluation methodology based on survival analysis and longitudinal data as an alternative to the EB/FB method. A Bayesian survival analysis (SARE) model with a random effect term to address the unobserved heterogeneity across sites is developed. The proposed survival analysis method is validated through a simulation study before its application. Subsequently, the SARE model is developed in a case study to evaluate the safety effectiveness of a recent red‐light‐running photo enforcement program in New Jersey. As demonstrated in the simulation and the case study, the survival analysis can provide valid estimates using only data from treated sites, and thus its results will not be affected by the selection of defective or insufficient reference sites. In addition, the proposed approach can take into account the censored data generated due to the transition from the before period to the after period, which has not been previously explored in the literature. Using individual crashes as units of analysis, survival analysis can incorporate longitudinal covariates such as the traffic volume and weather variation, and thus can explicitly account for the potential temporal heterogeneity.     

腔内电光调制激光系统的混沌模拟

采用数值模拟的方法讨论了带反馈的腔內电光调制激光系统功率输出的分叉和混沌行为,得到了输出功率随控制参数变化的分叉图,和一些定量结果。     

用联想神经网络设计的信道均衡器

研究了联想神经网络在数字通信信道均衡器实现中的应用,讨论了其设计方法和设计步骤,给出了计算机模拟结果,并进行了性能比较。研究结果表明:Hopfield联想神经网络实现的信道均衡器具有比传统线性横向均衡器更优越的性能。     

从GATT到WTO--全球多边贸易体系的发展

建立一个调整世界各国贸易关系的组织 ,以便在比较宽松的环境下开展国际贸易 ,是世界各国的共同愿望。经过战后近半个世纪的艰苦努力 ,从GATT到WTO ,在循序渐进的过程中 ,形成了当今比较完整的国际贸易体系