科技保险的困境—一个制度供求非均衡分析

现阶段，我国步入了创新驱动引领升级的关键时期，科技创新受到了整个社会的空前重视。科技保险作为分散和转移科技风险的重要手段，可以为科技创新提供有力的风险保障。目前，我国科技保险工作已经进入全面推广阶段，虽然取得了一定的成效，但整体运行并不理想，科技企业参保率低，科技保险缺失严重。究其原因，主要在于制度供给不能适应科技企业对科技保险的需求，科技保险制度供求非均衡，在现行的科技保险制度下积聚着大量的潜在利润，而这些潜在利润既是科技保险制度非均衡的原因，又是科技保险制度创新的动力。     

Regression analysis of case-cohort studies in the presence of dependent interval censoring

The case-cohort design is widely used as a means of reducing the cost in large cohort studies, especially when the disease rate is low and covariate measurements may be expensive, and has been discussed by many authors. In this paper, we discuss regression analysis of case-cohort studies that produce interval-censored failure time with dependent censoring, a situation for which there does not seem to exist an established approach. For inference, a sieve inverse probability weighting estimation procedure is developed with the use of Bernstein polynomials to approximate the unknown baseline cumulative hazard functions. The proposed estimators are shown to be consistent and the asymptotic normality of the resulting regression parameter estimators is established. A simulation study is conducted to assess the finite sample properties of the proposed approach and indicates that it works well in practical situations. The proposed method is applied to an HIV/AIDS case-cohort study that motivated this investigation.     

互联网深化、信息不确定性与企业出口平稳性

互联网作为信息搜寻和传播的重要渠道,有利于缓解国际市场不确定性对企业出口决策的影响,从而有助于稳定企业出口预期,保障出口企业的持续生存。本文首先基于Fernandes 和 Tang(2014)的研究框架将互联网深化程度和出口集聚同时纳入到异质性贸易企业模型,在剥离出口集聚对企业出口行为影响的基础上,从理论视角揭示了互联网深化程度提高影响企业出口行为特别是出口持续生存的内在机理与方向。研究发现,不同于出口集聚会同时影响企业的需求冲击和成本冲击,互联网深化带来的信息溢出效应会通过贝叶斯法则(Bayesian Rule)使得企业修正其对国际市场不确定性的预期,提高其对目的国市场成本冲击的估计精度,从而在互联网深化程度较高的城市,企业进入出口市场的临界生产率较低,有利于其出口参与度和出口稳定性的提高。然而互联网深化程度提高不影响企业在目的国市场产品出口的集约边际。本文使用2000-2013 年中国工业企业数据库、中国海关数据库和中国城市统计年鉴数据库的匹配数据从企业-目的国-产品层面实证检验了本文的理论命题。研究表明,我国政府应充分发挥互联网发展降低信息不确定性的微观机制,以推动外贸的平稳增长。     

An additive–multiplicative mean model for panel count data with dependent observation and dropout processes

This paper discusses regression analysis of panel count data with dependent observation and dropout processes. For the problem, a general mean model is presented that can allow both additive and multiplicative effects of covariates on the underlying point process. In addition, the proportional rates model and the accelerated failure time model are employed to describe possible covariate effects on the observation process and the dropout or follow‐up process, respectively. For estimation of regression parameters, some estimating equation‐based procedures are developed and the asymptotic properties of the proposed estimators are established. In addition, a resampling approach is proposed for estimating a covariance matrix of the proposed estimator and a model checking procedure is also provided. Results from an extensive simulation study indicate that the proposed methodology works well for practical situations, and it is applied to a motivating set of real data.     

基于网络表达的皖南乡村民宿消费体验与提升对策研究

民宿作为一种新型的住宿产品,是发展乡村旅游和丰富住宿业态的重要载体.对皖南民宿网络评价文本分析发现,住客对皖南民宿的消费体验感知主要体现在软件服务、硬件设施、周边环境以及入住体验四个方面,"老板"和"房间"是住客感知最为深刻的具体对象,住客网络评论中积极情感占据绝对地位,大部分要素的表现性得分较高,但民宿的位置、交通、餐饮等方面也存在一定的消极感知.可以从服务质量、地域文化以及品牌创建与宣传方面进一步提升皖南民宿住客消费体验质量,促进区域业态可持续发展.     

On the Changes of Modern Chinese Vocabulary: Taking"Nayun(拿云)"as an Example

"拿云"一词是近代汉语新产生的词汇,具有典型的动词性特点,其内部构造具有明显的动宾关系,可以充当定语、状语、宾语、谓语等成分.该词的语用风格具有典雅性,结构具有凝固性;其夸张义、比喻义也比较明显.该词的产生具有深厚的认知基础,具体表现为:基于隐喻的词义引申、语言的陌生化原则和基于构式"拿+X"的扩充."拿云"的词汇化始于语言的重新分析机制,历程是错综复杂的."拿云"的词汇化历程体现了部分近代汉语词汇的演变轨迹.     

从造字到造形：汉字形体结构与书法艺术

汉字作为一种书写形体，笔画组合的丰富多样和间架结构的灵活多变，而使其“字形”成为复杂的美学构成，“书写”成为“书法”，并完成从造字到造形的转变。书法是汉字书写艺术，书法艺术深藏于汉字独特的形体结构之中。三位一体的整体架构、二维方块结体、平衡对称等汉字在形体构造上的诗性特征，既是人们对文字形体的一种审美预期，也是书法学家在书法创作时努力追求的美感。     

A sampling plan for one-shot systems considering destructive inspection

Abstract

The paper is concerned with an acceptance sampling problem under destructive inspections for one-shot systems. The systems may fail at random times while they are operating (as the systems are considered to be operating when storage begins), and these failures can only be identified by inspection. Thus, n samples are randomly selected from N one-shot systems for periodic destructive inspection. After storage time T, the N systems are replaced if the number of working systems is less than a pre-specified threshold k. The primary purpose of this study is to determine the optimal number of samples n*, extracted from the N for destructive detection and the optimal acceptance number k*, in the sample under the constraint of the system interval availability, to minimize the expected cost rate. Numerical experiments are studied to investigate the effect of the parameters in sampling inspection on the optimal solutions.