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.     

网络视频会议系统——一种现代远程教育解决方案

通过对目前现代远程教育应用的技术系统的分析比较 ,提出了一种基于网络视频会议系统的现代远程教育解决方案     

Model Diagnostics for Remote Access Regression Servers

To protect public-use microdata, one approach is not to allow users access to the microdata. Instead, users submit analyses to a remote computer that reports back basic output from the fitted model, such as coefficients and standard errors. To be most useful, this remote server also should provide some way for users to check the fit of their models, without disclosing actual data values. This paper discusses regression diagnostics for remote servers. The proposal is to release synthetic diagnostics—i.e. simulated values of residuals and dependent and independent variables–constructed to mimic the relationships among the real-data residuals and independent variables. Using simulations, it is shown that the proposed synthetic diagnostics can reveal model inadequacies without substantial increase in the risk of disclosures. This approach also can be used to develop remote server diagnostics for generalized linear models.     

基于客户/服务器模式的非正常RPC的研究

分析了客户／服务器模式下远程过程调用(RPC)原理及其实现方法，重点讨论了五种非正常情况下RPC的处理方法。     

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′。     

Remote Work in Library Technical Services: Connecting Historical Perspectives to Realities of the Developing COVID-19 Pandemic

Abstract

The concept and practice of remote work in library technical services is not new, but the scale and speed of the transition to remote work for many libraries due to the COVID-19 pandemic is unprecedented. This column provides an overview of pre-pandemic literature on remote work in library technical services and briefly examines the history, planning, case studies, technology and equity concerns, challenges, and potential benefits of remote work. Initial connections are drawn between existing literature and the impact of the pandemic on remote work, and future directions for research and discussion are offered.     

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.     

广西边远地区农村教育资源闲置问题实证研究——以百色为例

教育资源闲置是教育资源完全或部分没有发挥教育功能的状态,具有绝对闲置和相对闲置两种含义。文章以百色农村教育资源为例,分析了广西边远地区农村教育资源闲置在小学和初中两个层面的表现,并分析了造成广西边远地区农村教育资源闲置的原因;文章认为,提高广西边远地区农村经济发展水平、拓宽融资渠道、优化教育资源配置、灵活撤并教学点、改变闲置校舍的用途以及合理解决代课教师问题是解决广西边远地区农村教育资源闲置问题的可能途径。     

唐代迁谪诗文述略

唐代遭受迁徙、贬谪之苦的众多诗人所创作的“迁谪诗文” ,是唐代文学不可或缺的重要组成部分。唐代的迁谪诗文颇能体现出迁谪文学的本质特点 ,对后世的迁谪文学的发展亦产生了深远的影响。