Markov chain Monte Carlo methods for high dimensional inversion in remote sensing

Summary.  We discuss the inversion of the gas profiles (ozone, NO₃, NO₂, aerosols and neutral density) in the upper atmosphere from the spectral occultation measurements. The data are produced by the 'Global ozone monitoring of occultation of stars' instrument on board the Envisat satellite that was launched in March 2002. The instrument measures the attenuation of light spectra at various horizontal paths from about 100 km down to 10–20 km. The new feature is that these data allow the inversion of the gas concentration height profiles. A short introduction is given to the present operational data management procedure with examples of the first real data inversion. Several solution options for a more comprehensive statistical inversion are presented. A direct inversion leads to a non-linear model with hundreds of parameters to be estimated. The problem is solved with an adaptive single-step Markov chain Monte Carlo algorithm. Another approach is to divide the problem into several non-linear smaller dimensional problems, to run parallel adaptive Markov chain Monte Carlo chains for them and to solve the gas profiles in repetitive linear steps. The effect of grid size is discussed, and we present how the prior regularization takes the grid size into account in a way that effectively leads to a grid-independent inversion.     

审视经济全球化

由于各国经济发展的不平衡,经济全球化的当代特征表现为三角化、区域一体化和跨国公司的迅速崛起。经济全球化正在改变现有政治格局,推动世界政治朝全球性方向演进并形成全球性的治理机构或协调治理形式。在以发达国家为主导、跨国公司为主要动力的经济全球化过程中,中国作为发展中国家在国际竞争方面处于弱势,这要靠全党全民运用自己的智慧和力量,利用自己已经具备的各种有利条件去应对全球化的挑战。从人类社会经济形态演进的自然历史过程看,经济全球化不过是资本主义的社会化生产和市场全球性扩张的新的历史阶段。从马克思的立场看,全球化将会是资本主义时代的终结,并为社会主义社会的到来做好准备,随全球化而来的将是一个更加美好的新世界。     

美国跨国公司内部贸易问题研究

内部贸易已成为跨国公司实现其全球化战略的重要工具 ,并且跨国公司内部贸易在贸易方式、贸易规模上的实质性演变对整个国际贸易体系和世界经济发展方向的影响力度逐步加大 ,对我国整个国民经济的发展以及政策法规的制定都有重要的意义。因此 ,本文主要从美国跨国公司内部贸易的具体分析入手 ,对跨国公司内部贸易所独有特性和决定因素进行研究 ,以期望对我国跨国公司“走出去”的战略起到一定的指导作用。     

Attracting Micro‐Enterprises To Learning

Micro‐enterprises, i.e. firms with less than 10 employees, are traditionally the hardest to engage in learning; they are also least likely to participate in such measures as business advice and guidance provision and initiatives to support information communication technology (ICT) adoption. Through a community‐based initiative initially targeting parents (unemployed or employed) to participate in ICT, 30 micro‐enterprises were attracted to learning for the first time. These companies had carefully avoided similar initiatives taking place locally, which emphasized business success and growth; they had only participated in this ICT skills training because of their children. The paper takes a case study approach to evaluate the reasons for participation, explores barriers and implications for those organizing similar activities, and calls for a more holistic view of owners and managers of small firms as fathers, mothers, etc. rather than just as ‘entrepreneurs’.     

中小企业成长的社会网络解释与分析

中小企业成长依赖于外部资源获取,而资源获取渠道又通常产自于由各种社会关系构成的社会网络。本文针对中小企业成长的独特轨迹,认为社会网络理论在中小企业资源获取及在此基础上的持续成长方面具有独到的解释与分析力度。此外,对社会网络的演进模式及其在中小企业资源获取与成长过程中发挥的作用进行了分析。最后,对社会网络理论在中小企业成长方面可能的具体研究应用领域进行了探讨。     

农产品电商集群企业地理邻近性对协同创新绩效的影响

基于知识治理视角,构建农产品电商集群企业地理邻近性、知识治理、知识共享和协同创新绩效关系的链式中介模型,并引入网络关系强度作为调节变量,结合341家农产品电商集群企业的调研数据,采用多层次回归和Bootstrap分析方法,分析地理邻近性对协同创新绩效的直接作用,检验知识治理和知识共享的独立中介作用和链式中介作用,以及网络关系强度的调节作用。结果表明：地理邻近性正向影响协同创新绩效;知识治理在地理邻近性和协同创新绩效间发挥中介作用;知识共享在知识治理和协同创新绩效间发挥中介作用;知识治理和知识共享在地理邻近性和协同创新绩效间发挥链式中介作用;网络关系强度正向调节正式知识治理和显性知识共享的链式中介作用。因此,农产品电商集群企业要把握数字经济发展契机,善于利用集群区位优势和产业资源,激发正式知识治理和非正式知识治理的双重效应,与合作企业建立良好的知识共享关系,实现高质量协同创新发展。     

具有网络外部性的产品兼容性决策分析

通过Stachelberg竞争模型,本文研究了在具有网络外部性的市场中,拥有专有技术的主导厂商对其兼容技术的授权动机问题。并且得到了主导厂商在纵向兼容决策中最优厂商数量的控制的关系。     

城市规模、创业边界与企业家创业

大城市更有活力且更年轻化的人口结构,导致大城市的消费者异质性偏好更强,进而可能推动企业家创业边界的降低与城市创业活动的发展。为了识别这一理论机制,本文在Zhelobodko et al.（2012）的分析框架上,通过引入城市规模和消费者异质性偏好假设,构建了一个异质性企业家区位选择与创业的空间经济学模型,考察城市规模通过企业家创业边界对城市创业活动的影响,并基于2000-2016年204个城市的面板数据以及2008年中国经济普查数据进行了实证检验。研究发现：（1）企业家才能越高的企业,相应的产品定价会越低,产品需求量越大,而利润越高;（2）企业家创业边界除了受到城市规模的影响以外,还会受到消费者多样性偏好的影响;（3）消费者多样化偏好更强的城市,城市的创业门槛更低,城市的创业活跃度更高。     

Wikipedia in the anti-SOPA protests as a case study of direct,deliberative democracy in cyberspace

This paper contributes to the discussion on deliberative, direct democracy and volunteer mobilization in the Internet era by analyzing the vote participation levels of Wikipedia volunteer editors (Wikipedians). On 18th January 2012 in the ‘first Internet strike’ against the American ‘Stop Online Piracy Act' legislation, over two thousand Wikipedians took part in the vote concerning whether their site should undertake a protest action, with vast majority expressing support for this action. However, the vote participants formed only a tiny fraction of the total number of Wikipedians who number in millions. Although Wikipedia can be seen as an open, democratic forum practicing deliberative, direct democracy, the process of voting on Wikipedia is significantly influenced by participation inequality, with a majority of the vote participation coming from a small group of most active contributors – an effective oligarchy. This paper discusses the intricate dynamics between Wikipedia egalitarian ethos and the creed to discuss project matters deliberately on one hand and the conspicuous lack of promotion and advertisement stemming from a rule against ‘canvassing’ and an overall skepticism regarding the status of majority votes. While voters' passivity and lack of interest play a major role, as expected, another factor emerges as a significant factor responsible for the low levels of participation: an inefficient information distribution system, as the vast majority of Wikipedians were not aware of the ongoing discussions and the vote itself until after their conclusion.     

Multilevel embeddedness: The case of the global fisheries governance complex

This paper explores how bilateral and multilateral clustering are embedded in a multilevel system of interdependent networks. We argue that in complex systems in which bilateral and multilateral relations are themselves interrelated, such as global fisheries governance, embeddedness cannot be reduced to unipartite or bipartite clustering but implicates multilevel closure. We elaborate expectations for ties’ multilevel embeddedness based on network theory and substantive considerations and explore them using a multilevel ERGM. We find states’ bilateral ties are embedded in their shared membership in multilateral fisheries agreements, which is itself clustered around foci represented by similar content and treaty secretariats.