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.     

从环境和建筑看生态建筑设计

建筑师和生态学家对环境和建筑的认识存在着一定的差异。生态建筑设计需要建筑师借鉴生态学家的认识 ,建立一种整体的建筑观念。依托整体生态观和系统观念建立起来的整体生态建筑观包括两个方面的内容 :其一是建筑系统在全寿命过程中 ,持续地与周围生态系统环境相互作用 ;其二是建筑系统对周围生态系统会产生空间置换影响 ,而这种影响具有一定的空间范围     

趋向动词的范围及意义

趋向动词在现代汉语里是一个相对封闭的类,前人多有论述,但对它如何分类,如何区分,判断的标准以及它的范围和意义等问题看法不尽相同。根据语义分析,趋向动词的标准应确定为:位移 方向 立足点。趋向动词的句法以常带来表示起点或终点的处所宾语和前边可以有处所状语修饰为特点。趋向动词在历史上是有变化的,有的逐渐退出了历史舞台,而有的一般动词却发展出了趋向动词的用法。     

Tree health mapping with multispectral remote sensing data at UC Davis, California

Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy. At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling and analysis of the environmental, social, and economic services produced by urban forests.     

光纤转角、位移传感器的理论研究

提出了“光纤桥”新概念,利用“光纤桥”构成了测量转角、位移的光纤传感器。利用准高斯光束假设,详细地分析、计算了系统参数对传感器性能的影响,理论上预见了测角精度可达1”,测角范围±6′。     

基于多模态学术英语口语语料库的中国理工科大学生单词重音位移研究

基于自建多模态学术英语口语语料库对中国理工科大学生单词重音位移进行研究,分析了主要单词重音位移、主要单词重音位移分布、不同年级不同性别学生之间重音位移标准频数以及是否具有显著性差异。研究表明,单词重音位移主要发生在多音节词发音中,并且单词重音位移至第二音节的频次最多。从不同年级、不同性别学生之间的对比分析来看,一年级学生重音位移标准频数多于二年级学生,女生重音位移标准频数多于男生,但不同年级、不同性别学生之间重音位移均不具有显著性差异。在总结研究结果的基础上提出教学和学习建议。     

新闻标题的传播环境与实践问题分析

新闻作品文本的标题具有不同于文学作品文本标题的语境特点,主要表现在新闻内容要素对标题具有强烈的制约性,且标题往往可以在文本完成之后再拟制或再进行修改.新闻标题的语境特殊性给一些标题修辞手法的使用提供了机缘,移脱、活化、对比、飞白等标题制作方法经常在新闻标题中广泛使用.     

Sensuous stories in the Indian Ocean islands*

Abstract

Providing examples from the islands of the Indian Ocean Region, this article focuses on the multisensory nature of storytelling and listening. Drawing on anthropological fieldwork in the region (1998–2016), the author proposes a sensuous epistemology that turns on listening to “sense”. She reveals that storytelling can be a profoundly sensuous experience that elicits emotional and physical responses in both the teller and listener. The sensuous quality of stories enable the listener to fully encounter politically inscribed, complex social experiences. Ultimately, the article advances a notion of listening as sense-work, thereby deepening sensory scholarship’s recent, politically reflexive analysis on listening to hear.     

‘There it will be better … ’: Southern Sudanese in Khartoum imagining a new ‘home’ away from ‘home’

At the time of the research, Khartoum was a multi-ethnic and multinational metropolis of 8 million people. A considerable part of the population consists of Southern Sudanese migrants and displaced persons that came during the 20 years plus of civil war in South Sudan to the capital. These people were categorised after the Comprehensive Peace Agreement (CPA), as displaced people regardless as to whether they come to the capital as labour migrants, students or because of the war to the capital. The notion of displacement assumes that they are people who are ‘out of place’: thereby assuming a former situation of being in place, a place that can be called ‘home’. After the CPA from 2005, this frequently only imagined home became a real place for the IDP’s to which they are supposed to go back. Yet, many migrants and displaced people are reluctant to move to Southern Sudan. Their decision about going to the South or staying in Khartoum depends not only on the opportunities and perspectives in their respective ‘home’ areas but also on the perceptions of belonging and identity. The imaginations and aspirations about the future life in South Sudan, which I analyse in this article, reflect this ambivalent positioning.     

天然岩芯化学驱采收率机理的一些认识

用牛顿流体驱替一定的均质多孔介质系统结果显示，驱油效率由驱替液的毛管数决定。用化学液驱替天然岩芯时，除毛管数以外，还有很多其他因素影响驱油效率。天然岩芯，即使在宏观上是均匀的，在微观上也不均匀；驱替时所得到的效率一般被称为驱油效率，实质上是微观波及效率和驱油效率的乘积。牛顿流体没有弹性，驱替时，体系的润湿性不发生变化，不出现渗吸作用，不形成乳液，孔隙的几何形状不发生变化。但是，用化学液驱替天然岩芯时，由于化学液为粘弹性，体系有润湿性的改变，会出现乳化现象，渗吸作用也会出现。上述因素都会影响驱油效率，尤其是当多种因素同时作用时。分析了极限采收率和经济采收率的区别。很多文章都论述极限采收率，但经济采收率对油田的作用更大。化学驱应考虑上述因素，这对设计、开发、筛选化学剂以及确定驱油体系会是有益的，将深化我们对化学驱机理的认识，促进这方面更深入的研究。