基于Chebyshev正交分解的曲线运动轨迹SAR的Chirp Scaling算法

针对具有三维速度和加速度的曲线运动轨迹合成孔径雷达（SAR），传统的斜距模型无法精确描述其运动特性，曲线历程增加了距离走动现象和方位向时间的高次项，使二维耦合现象更为复杂。本文提出了一种考虑载体平台三维速度和加速度的Chirp Scaling算法以解决曲线运动轨迹SAR成像问题。首先根据运动方程建立斜距表达式，然后对其进行Chebyshev近似，并构造其等效双曲方程形式的斜距模型，推导了具有空变性的距离徙动函数，Chirp Scaling因子以及适用于曲线轨迹的Chirp Scaling成像算法。仿真结果证实了此扩展的等效斜距模型和Chirp Scaling算法在大合成孔径时间下的有效性，并给出了三维加速度的边界值。     

The new debate on the working methods of the UNCOPUOS Legal Subcommittee

The 2014 session of the Legal Subcommittee (LSC) of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) saw a particularly extensive and thorough debate on the working methods of this forum, which has the status of the highest body in space law making. By discussing the working methods it also became apparent how delegations actually regard the LSC and what expectations they have from it. In a time of considerable changes in space activities and space diplomacy alike, it was only a matter of time that such a comprehensive discussion arose. And while it did not immediately lead to decisions, it provided numerous signals for the future of the LSC.     

浅谈网络信息对公共决策的影响

对网络信息在公共决策中的两面性进行分析，以促进网络信息在公共决策中更好地发挥功能。     

2010年我国房地产业的政策导向与发展趋势

房地产业是我国国民经济发展的支柱产业,确保房地产业健康稳定发展不仅有助于我国抵御经济危机,而且是预防通胀的重要措施.在我国经济复苏这段时期内,国家将对房地产市场进行结构优化,包括支持保障性住房的发展、遏制投机行为、科学测算用地指标、严格规范土地储备、打击"囤地"行为等,以达到房地产市场和谐稳定发展的目标.     

Investigation of national policy shifts to impact orbital debris environments

Low earth orbit has become increasingly congested as the satellite population has grown over the past few decades, making orbital debris a major concern for the operational stability of space assets. This congestion was highlighted by the collision of the Iridium 33 and Cosmos 2251 satellites in 2009. This paper addresses the current state of orbital debris regulation in the United States and asks what might be done through policy change to mitigate risks in the orbital debris environment. A brief discussion of the nature of orbital debris addresses the major contributing factors including size classes, locations of population concentrations, projected satellite populations, and current challenges presented in using post-mission active debris removal to mitigate orbital debris. An overview of the current orbital debris regulatory structure of the United States reveals the fragmented nature of having six regulating bodies providing varying levels of oversight to their markets. A closer look into the regulatory policy of these agencies shows that, while they all take direction from The U.S. Government Orbital Debris Mitigation Standard Practices, this policy is a guideline with no real penalty for non-compliance. Various policy solutions to the orbital debris problem are presented, ranging from a business as usual approach to a consolidated regulation system which would encourage spacecraft operator compliance. The positive aspects of these options are presented as themes that would comprise an effective policy shift towards successful LEO conservation. Potential economic and physical limitations to this policy approach are also addressed.     

Overview of current capabilities and research and technology developments for planetary protection

The pace of scientific exploration of our solar system provides ever-increasing insights into potentially habitable environments, and associated concerns for their contamination by Earth organisms. Biological and organic-chemical contamination has been extensively considered by the COSPAR Panel on Planetary Protection (PPP) and has resulted in the internationally recognized regulations to which spacefaring nations adhere, and which have been in place for 40 years. The only successful Mars lander missions with system-level “sterilization” were the Viking landers in the 1970s. Since then different cleanliness requirements have been applied to spacecraft based on their destination, mission type, and scientific objectives. The Planetary Protection Subcommittee of the NASA Advisory Council has noted that a strategic Research & Technology Development (R&TD) roadmap would be very beneficial to encourage the timely availability of effective tools and methodologies to implement planetary protection requirements. New research avenues in planetary protection for ambitious future exploration missions can best be served by developing an over-arching program that integrates capability-driven developments with mission-driven implementation efforts. This paper analyzes the current status concerning microbial reduction and cleaning methods, recontamination control and bio-barriers, operational analysis methods, and addresses concepts for human exploration. Crosscutting research and support activities are discussed and a rationale for a Strategic Planetary Protection R&TD Roadmap is outlined. Such a roadmap for planetary protection provides a forum for strategic planning and will help to enable the next phases of solar system exploration.     

European space research in support of international partnership

The envisaged future space research programmes, whether in the field of space exploration or Earth observation are becoming more and more technically complicated and so costly that a single nation can hardly afford to realize them. Major non-European space-faring nations, China and India will progressively play an important role besides US, Russia and Japan. The Space Advisory Group of the European Commission recommended that the European Commission supports within Horizon 2020 a comprehensive Robotic Mars-Exploration Programme under European leadership that should become an essential element of a coordinated international space research programme. The International Space Station (ISS) experience shows that cooperative space programmes build links between industries and laboratories from around the world, which then further develop in non-space related activities, with positive impact on the economy and scientific research. Strategies need to be developed to mitigate the gradual increasing risks incurred by climate change. In order to lower their entry barrier to engage in space emerging and developing space nations need to be included in cooperative space programmes. We present the recommendations of the Space Advisory Group of the European Commission concerning Europe's participation to global space endeavours.     

高校收费的定价模型与助学贷款有关问题的研究

本文论述了高校收费定价应充分考虑居民收入水平等诸多方面,国家应成为办学的主体。要解决贫困生上大学的学费及生活费问题,就必须抓紧建立全国性个人征信机构,成立国家助学贷款政策性银行。     

武汉城市圈建设中的产业政策选择——从产业集聚效应的角度分析

武汉城市圈虽然城市密集，基础较好，但是城市圈内各城市间没有形成良好的分工合作，产业低水平重复，资源配置效率低下。通过运用计量经济学工具，建立集聚经济的分析框架，测算武汉城市圈内各城市的产业集聚效应，来探讨武汉城市圈建设中的产业政策选择问题。通过分析我们发现，在武汉城市圈中，黄冈市、成宁市和天门市不适合优先发展工业．因此未来要增强自身经济集聚能力，加快经济发展速度，与武汉城市圈整体发展水平相协调；武汉市和仙桃市适合优先发展轻工业；黄石市、鄂州市、孝感市和潜江市适合优先发展重工业。     

The essential role of human spaceflight

The question is: should the United States and nations at large pursue a human spaceflight program (and if so, why)? I offer an unwavering positive answer to this question, and state the reasons for it while considering the broad challenges and benefits of (human) spaceflight. Space exploration is a human activity that is intrinsically forward-looking, and as such, has positive potential. Both national and international space programs can galvanize the population, inspire the youth, foster job-creation, and motivate the existing workforce. The nature of the enterprises involved—their scale, novelty, and complexity—requires a steady and continuous upward progression toward greater societal, scientific and technological development. That is, in order to overcome the challenges of human spaceflight, progress is required. More to the point, the survival of humanity depends on expanding beyond the confines of our planet. Human spaceflight, in short, presents us with an opportunity to significantly advance the nation and the global community.