山区测绘型低空无人机航线设计及优化研究

近年来无人机越来越多的应用于低空航测,如何保证外业质量和效率是很必要的。结合实际经验与影响测绘型低空无人机航线设计的主要因素、基本参数,文章重点介绍了航线设计的一般步骤和在地形起伏较大区域选用高像素,长焦距相机对地面分辨率、航摄分区面积、作业效率的影响;以及如何确保航片间有足够的重叠度,如何在分区内优化航线。提出了高像素,长焦距相机对起伏较大区域有更好的适用性。     

基于复杂适应系统理论的我国企业集团协同管控模式研究

如何实现有效的集团管控是长期以来困扰企业管理者的难题之一,复杂适应系统理论的提出,为解决这一方面问题提供了新的思路。本文旨在通过对企业集团系统性以及内外部环境的分析,阐明企业集团管控与内部整合两者的统一性,基于复杂适应系统理论提出企业集团协同管控模式以及通过实施内部整合建立该模式的思路,为企业管理者解决集团管控问题提供有价值的参考。     

论自适应选频对短波通信质量的改善

短波通信是发展较早的一种通信技术,广泛应用于多个领域。文章分析了短波信道中数字信号的传输特性,并用实例验证了自适应选频对于短波通信质量的改善效果,进而提出改善短波信道特性对数字信号传输质量的措施。     

卫星通信抗干扰设计考虑及性能分析

提出了直接序列扩频和自适应调零天线相结合的卫星通信抗干扰设计思路,针对不同干扰条 件和不同卫星转发方式,进行了系统抗干扰性能的理论分析,结果表明,直接序列扩频和自 适应调零天线相结合,经星上再生处理转发可有效提高系统抗干扰能力。相关分析与结论对 工程应用具有一定的参考意义。     

中继卫星SMA系统反向链路多波束形成技术

对中继卫星SMA(S频段多址)反向链路多波束形成开环数字波束形成算法（DBF）、3种闭环自 适 应数字波束形成算法进行了分析,通过试验验证了开环波束形成算法和闭环波束自适应 形成算法的可行性。试验结果表明,在飞行器捕获、跟踪的不同阶段,采用开环波束形成与 自 适应波束形成相结合是SMA反向链路波束形成的最优方式。     

集成适应理论在城市道路景观设计中的应用

分析了我国城市道路景观存在的问题,在将城市道路景观作为一个复杂网络综合体的基础上,从系统范畴的角度探讨了"集成适应"道路景观设计理念,为未来我国城市道路景观建设提供了一种新的思路.     

运河船舶检测系统

为了满足运河航运船舶管理的需要，提出了以RFID和视频为对象检测技术相结合的运河船舶检测系统方案．针对河道视频检测环境较为复杂的特点，提出采用像素归类法与基于块的背景确定方法进行背景建模，并利用运动速度进行目标检测．实验结果表明，系统船舶检测具有良好的实时性和鲁棒性．     

疫情对经济的影响与“灾害适应型经济”的转型

新型冠状病毒肺炎疫情对中国乃至世界经济产生了巨大的冲击。疫情的冲击颠覆了传统经济学的认知，需从理论上对经济衰退的原因和机制重新认识，特别是对疫情之下“非常态经济”及其与“常态经济”之间的关系加以研究；疫情的冲击亦暴露出现有的经济系统存在的问题，需要推动经济的转型，打造“灾害适应型经济”。本文基于辩证思想，从负面和正向两个方面来研究疫情对经济的影响，充分发掘新动能，利用新机会，推动中国经济向“灾害适应型经济”转型，实现中国经济的可持续、高质量发展。     

Constructing Commercial Indices: A Semiparametric Adaptive Estimator Approach

Constant-quality commercial indices generated by ordinary least squares may suffer an efficiency loss due to leptokurtosis caused by outliers in transactions data. When the subsequent nonnormality occurs, substantial improvement in index precision is obtained by estimating the hedonic model using a semiparametric adaptive estimator technique. When this method was applied to 1,846 office transactions that occurred in the Phoenix metropolitan area from January 1997 through June 2004, a substantial standard error reduction of approximately 9% was realized relative to ordinary least squares estimates. The difference in average returns between the semiparametric method and ordinary least squares was about 0.25% in each period, which represents a substantial increase in commercial property index precision. JEL Classification C4 R0     

Drivers of flood and climate change risk perceptions and intention to adapt: an explorative survey in coastal and delta Vietnam

Abstract

This article contributes to current research about determinants of climate change and flood risk perception, and intentions to take adaptive measures. We propose a research model that distinguishes between vulnerability and severity components of perceived risks, and adds perceived adaptive capacity as a third factor to predict the intention to take adaptive measures. We used this combined model as a conceptual lens for an explorative survey among 1086 residents of coastal and delta communities in Vietnam. Pairwise analyses revealed a significant association of flood and climate change risk perceptions with individual’s flood experience, climate change knowledge, frequency of community participation and socio-demographic factors. However, in multivariate analysis, the influence of most socio-demographic factors became weak or patchy. Flood experience was the most influential driver of flood-related risk perceptions but weak for climate change-related risk perceptions and behavioural intentions. Knowledge strongly increased the intention to adapt to flood and climate risks and the perceived vulnerability to and severity of climate change risks, but reduced the perceived capacity to adapt to climate risks. Frequency of community participation increased the perceived vulnerability and severity of climate change risks, the intention to adapt to both climate and flood risks and the perceived capacity to adapt to flood risks, but reduced the perceived capacity to adapt to climate risks. Our research confirms earlier findings that individuals’ knowledge, place-specific experience and social-cultural influences are key predictors of both flood and climate change risk perceptions and intentions to take adaptive measures. These factors should therefore receive ample attention in climate risk communication.