基于单片机的无线遥控小车研究与实现

本文介绍了一种由STC12C5A60S2单片机控制的无线遥控小车,采用控传和图传独立设计的思想,即数据收发模块进行控制和温度数据的传输,图传模块负责作业环境的图像传输.控传部分以STC12C5A60S2单片机为核心,利用NRF24L01+模块数据收发,L298N电机驱动两路直流电机,使小车完成相应动作;DS18B20负责检测温度,由小车收发模块发射,LCD1602液晶模块显示.系统采用模块化设计,结构紧凑,便于优化,且可靠性能高.     

我国环境多元治理模式法律保障机制探究

未清晰地认识和定位政府、企业、社会公众三者的关系,未处理好三者的分工与衔接,是造成我国环境多元治理模式难以落实的关键问题。究其主要原因在于过分依赖传统政府管制模式的路径,以致政府在环境治理中起主导作用而轻视企业、社会公众作为治理主体的力量,导致其他治理主体参与环境治理法律机制的缺失。比较分析三者存在的障碍,提出落实环境多元治理模式法律保障的建议,从而构建起三者相互协作、共同治理环境的新局面。     

Collective versus Individual Effects in Survival Analysis of Multiple Failures

In survival analysis, we sometimes encounter data with multiple censored outcomes. Under certain scenarios, partial or even all covariates have ‘similar’ relative risks on the multiple outcomes in the Cox regression analysis. The similarity in covariate effects can be quantified using the proportionality of regression coefficients. Identifying the proportionality structure, or equivalently whether covariates have individual or collective effects, may have important scientific implications. In addition, it can lead to a smaller set of unknown parameters, which in turn results in more accurate estimation. In this article, we develop a novel approach for identifying the proportionality structure. Simulation shows the satisfactory performance of the proposed approach and its advantage over estimation under no assumed structure. We analyse three datasets to demonstrate the practical application of the proposed approach.     

A Rejection Principle for Sequential Tests of Multiple Hypotheses Controlling Familywise Error Rates

We present a unifying approach to multiple testing procedures for sequential (or streaming) data by giving sufficient conditions for a sequential multiple testing procedure to control the familywise error rate (FWER). Together, we call these conditions a ‘rejection principle for sequential tests’, which we then apply to some existing sequential multiple testing procedures to give simplified understanding of their FWER control. Next, the principle is applied to derive two new sequential multiple testing procedures with provable FWER control, one for testing hypotheses in order and another for closed testing. Examples of these new procedures are given by applying them to a chromosome aberration data set and finding the maximum safe dose of a treatment.     

Combining Inverse Probability Weighting and Multiple Imputation to Improve Robustness of Estimation

Inverse probability weighting (IPW) and multiple imputation are two widely adopted approaches dealing with missing data. The former models the selection probability, and the latter models data distribution. Consistent estimation requires correct specification of corresponding models. Although the augmented IPW method provides an extra layer of protection on consistency, it is usually not sufficient in practice as the true data‐generating process is unknown. This paper proposes a method combining the two approaches in the same spirit of calibration in sampling survey literature. Multiple models for both the selection probability and data distribution can be simultaneously accounted for, and the resulting estimator is consistent if any model is correctly specified. The proposed method is within the framework of estimating equations and is general enough to cover regression analysis with missing outcomes and/or missing covariates. Results on both theoretical and numerical investigation are provided.     

Functional Partial Linear Single‐index Model

This paper deals with the problem of predicting the real‐valued response variable using explanatory variables containing both multivariate random variable and random curve. The proposed functional partial linear single‐index model treats the multivariate random variable as linear part and the random curve as functional single‐index part, respectively. To estimate the non‐parametric link function, the functional single‐index and the parameters in the linear part, a two‐stage estimation procedure is proposed. Compared with existing semi‐parametric methods, the proposed approach requires no initial estimation and iteration. Asymptotical properties are established for both the parameters in the linear part and the functional single‐index. The convergence rate for the non‐parametric link function is also given. In addition, asymptotical normality of the error variance is obtained that facilitates the construction of confidence region and hypothesis testing for the unknown parameter. Numerical experiments including simulation studies and a real‐data analysis are conducted to evaluate the empirical performance of the proposed method.     

基于文献关键词统计分析的我国开放与远程教育研究现状探析

以中国知网（CNKI）为平台,利用共词分析方法,对2006年1月至2015年6月间公开发表在开放与远程教育领域期刊论文的关键词进行统计分析,结合SATI软件和UCINET软件进行数据处理,探讨高频关键词之间的内在联系,揭示我国开放与远程教育研究的主题结构和核心领域。结果表明：此间我国开放与远程教育领域主要存在七大研究主题;远程学习、网络课程、学习支持服务、学习者是该领域的研究核心;移动学习、内容分析、学习科学和远程学习者将成为未来的研究热点。     

1980年代“译介热”与中国审美话语的本体自律

20世纪80年代的“译介热”通过引进西方现代文论资源,实现了对政治意识形态“工具论”“反映论”的反拨与对抗,与此同构的是审美自律的进程和审美本体的建构.“审美自律论”和“方法多元论”成为“译介热”的两个主要支点,共同参与现代性人学启蒙,促使了现代派文学的文本发现与形式自律.“审美自律论”促使了审美活动从外部的“他律”转向了审美的“自律”,形式主义文论、结构主义文论等在译介热中引入中国,纷纷促使了美学和文学批评从外部转向内部、从内容转向形式、从思想内涵转向话语革命.同时也直接启发了中国现代派文学和先锋小说的创作,激活了新时期以来潜藏的“形式化”冲动,从而使得形式和语言实验在80年代中后期的文学创作中焕发出愈加重要的作用.     

农民工城市融入的组织化实践

不同于既有农民工城市融入研究中的宏观制度主义视角,也区别于单一组织微观实践路径的研究取向,文章基于粤南沙镇的实地调研经验,总结提炼出“半正式组织”这一新型实践类型,有助于弥合既有研究中的宏观与微观鸿沟。“半正式组织”是对现代组织“正式与非正式”二元对立框架的尝试性超越,在组织结构、成员关系、资源链接方式等方面均呈现新特征,其形成机制可概括为党建引领、组织挂靠与领袖吸纳。“半正式组织”的实践功效表现为助推农民工在流入地提升经济机会,增强政治参与,链接公共服务,扩展群体社会交往,因而成为现阶段有限制度供给和市民化成本分摊机制不均衡情境下,实现农民工城市融入的新路径。     

信任对农民创业机会识别的影响

基于信任视角,构建农民创业者信任对创业机会识别的理论分析框架,运用链式多重中介方法,对浙江、安徽、河南和陕西4省880份农民创业者访谈数据进行实证分析,结果发现:信任能显著提高农民创业机会识别;农民创业者信任能通过外部知识获取与创业警觉性对创业机会识别产生间接影响,其作用路径有三条:外部知识获取的部分中介作用、创业警觉性的部分中介作用及外部知识获取与创业警觉性的链式中介作用。因此,政府应完善农民创业相关规章与制度;推进农村文化建设,提高信任水平;增加农民创业知识与技能的供给,培养农民创业者的机会警觉性。