一种高能效低时延的LLN路由修复算法

由于低功耗有损网络(LLN)中无线链路的不稳定性和有损性，外部环境的干扰极易导致网络出现故障，从而严重影响网络性能，而LLN网络中现有路由修复算法存在控制开销冗余和修复时延较大等问题。为此，提出了一种高能效低时延的LLN路由修复算法(EELDR-RPL)。该算法通过采用“零额外控制开销通告链路故障及邻居节点信息”机制，使得链路故障节点的子节点能够及时获知链路故障以及链路故障节点的邻居情况；通过采用“自适应调整节点网络深度值”机制，使得链路故障节点能够快速地重新接入网络；通过采用“链路故障节点子节点自适应切换”机制，能够达到优化网络拓扑的目的。仿真结果表明，与现有路由修复算法相比，EELDR-RPL算法能够有效地降低路由修复时延和减少控制开销。     

旅游要素POI对夜间灯光指数的贡献及其空间特征分析

"吃、住、行、游、购、娱"旅游六要素的POI数据能反映出旅游相关对象的空间结构、分布形态和旅游空间实体所承载的社会经济功能,而夜间灯光影像是反映区域经济发展情况的重要手段。文章从旅游要素POI对夜间灯光指数的贡献视角,基于多元线性回归、空间自相关和地理加权回归方法,以湖南省122个县(市、区)为案例分析了旅游要素POI和灯光之间的关系和空间异质性。结果显示,购物服务、休闲娱乐、交通服务对灯光指数具有正向影响,观光游览对灯光指数具有负向影响,不同的旅游要素POI对灯光影响呈现明显的空间差异。这一特征是区域旅游活动、旅游经济发展综合作用的结果,研究内容为区域旅游研究提供了新的方法和视角。     

大跨度天基数据链的TDD时隙调度分析与优化

针对天基数据链系统卫星间的传播时延较大且节点间距离变化较大等特点，提出了一种提高时频资源利用率、提升系统容量、减小时延的方法。在时分多址与空分多址相结合的接入方式下，进行了时隙调度的分析与优化，利用卫星星座的空间复用与大跨度传播时延特性，采用时隙编排、收发状态调整、帧格式优化等手段，将信道利用率和系统容量提升了1倍，将卫星节点在某一方向获得服务的平均等待时间缩短为原来的1/4，提高了天基数据链系统的服务质量。     

The challenge of Chinese state‐affiliated multinationals in benefiting from foreign subsidiary knowledge transfer: A criticism of light‐touch integration

Acknowledging the sharp growth of Chinese state‐affiliated multinationals and their strategic asset‐seeking investments abroad, this study investigates the effects of headquarters' home‐country political ties on the multinational‐wide benefits gained from subsidiary knowledge transfer in Chinese multinationals. It also looks at how these effects are mediated by organizational distance and social integration between headquarters and subsidiary. Based on a survey of 177 subsidiaries of 99 Chinese multinationals, we find that headquarters' political ties trigger organizational distance and hinder social integration between headquarters and foreign subsidiaries and these, in turn, hamper the potential benefits that Chinese multinationals derive from subsidiary knowledge transfer. This study identifies new challenges related to political ties and light‐touch integration in gaining benefits from subsidiary knowledge transfer.     

微纳卫星组网星间链路设计及关键技术分析

微纳卫星组网应用可大幅度提高航天装备的能力，较单颗大卫星具有明显的优势。首先，介绍了国内外微纳卫星组网的研究情况，以组网侦察应用为例分析了星间测量与通信链路的技术需求，并进行了系统架构和体制设计；其次，在星座设计基础上开展系统仿真，并提出了一体化设备实现方案；最后，分析了微纳卫星组网系统中几项重要的关键技术及其解决方案，对系统的设计和工程实现具有参考价值。     

偏光显微镜法在空气粉尘中石棉纤维鉴别中的应用

本文采用偏光显微镜法鉴别空气粉尘中的微量石棉纤维。经滤膜收集的粉尘样品通过高温灰化及酸洗过程去除大部分干扰物质,经乙醇分散后均匀沉积在玻璃片上,滴加具有固定折射率的浸油制成试片。在正交偏光系统下观察到粉体中存在纤维状颗粒,且纤维呈现四次平行消光特性,比对6种常见石棉的偏光显微镜图,综合分析试样粉尘的光学性质,推断样品中含有温石棉。     

The role of fundamental motivations in willingness-to-pay online

This study aims to determine whether an understanding of chronic fundamental consumer motivations can help determine the mechanisms of willingness-to-pay for products online. To do so, it employs a simulated buying task on a fictional e-commerce site for a consumer product (branded either as a “new arrival” or a “classic”) to investigate the effects of two fundamental motivations (mate acquisition vs. self-protection) on willingness-to-pay for the product online. The primary focus of the paper to investigate the capacity of mate acquisition and self-protection motives to moderate the relationship between attitude toward the product and willingness-to-pay, as well as, the effects of the motives on willingness-to-pay are considered. Through regression and interaction effect analyses, it is shown that chronic fundamental motivation for mate acquisition is directly correlated with an increased willingness-to-pay for both product types, and it moderates the relationship between attitude toward a product and willingness-to-pay. Self-protection motivation increases willingness-to-pay for classic products but not new arrivals. By offering a rare look at chronic fundamental motivation in the consumer context and potentially being the first investigation of the moderating effects of fundamental motivations, the results mostly support the notion of predictable motivation induced behavioral tendencies.     

Preventing motor vehicle crash injuries and deaths: science vs. folklore lessons from history

Abstract

Not long after the beginnings of motorization in the early 1900s, deaths and injuries from motor vehicle crashes became a problem in a number of high-income-countries (HIC)s, especially the United States. With the biggest problem the US led early efforts to address this issue, and for six decades these efforts were based on folklore (ie a body of widely held but false or unsubstantiated beliefs). They were not evaluated, but clearly were unsuccessful as crash deaths and injuries continued to rise. It was not until the 1970s that a broader range of countermeasures began to be adopted and was scientifically evaluated, and as a result, crash deaths and injuries declined. This history has important lessons today for many low-and-middle-income countries that have growing numbers of motor vehicle crash deaths and injuries, many of which are pedestrians and motorcyclists. This is because there continue to be advocates for many of the failed approaches (especially educational) that dominated the early efforts in HICs.     

An empirical analysis of night-time light data based on the gravity model

This article aims to explore the feasibility of applying night-time light data to the study of trade. Based on 61 countries’ panel data from 1995 to 2012, this research used night-time light data, as the substitute for GDP, to study trade development based on the traditional gravity model. The method of ordinary least squares, Poisson pseudo-maximum-likelihood and two-stage least squares were used. The results show that geographical distance, country borders and regional agreements have a significant effect on China’s trade with other Belt and Road countries, which verifies the validity of trade research based on night-time light data analysis. Additionally, comparisons reveal the trade trends predicted by night-time light data from 1996 to 2012, were highly consistent with the actual data. This article stands as the first study to apply night-time light data to the gravity model in the research on trade between China and other Belt and Road countries. Breaking new ground, this research uses night-time light data as an economic indicator to study trade, in combination with micro foundations and the latest findings of the gravity model. Thus, this article deepens the understanding of trade analysis and contributing to the field of related researches.     

数字图书馆防盗链设计以及实现研究

数字资源的拥有者应该设计图书馆数字资源的防盗链方案,提升数字图书馆的防盗链能力。本文通过对数字图书馆的了解,进行数字图书馆防盗链设计的研究。