Varying-time random effects models for longitudinal data: unmixing and temporal interpolation of remote-sensing data

Remote sensing is a helpful tool for crop monitoring or vegetation-growth estimation at a country or regional scale. However, satellite images generally have to cope with a compromise between the time frequency of observations and their resolution (i.e. pixel size). When concerned with high temporal resolution, we have to work with information on the basis of kilometric pixels, named mixed pixels, that represent aggregated responses of multiple land cover. Disaggreggation or unmixing is then necessary to downscale from the square kilometer to the local dynamic of each theme (crop, wood, meadows, etc.).

Assuming the land use is known, that is to say the proportion of each theme within each mixed pixel, we propose to address the downscaling issue through the generalization of varying-time regression models for longitudinal data and/or functional data by introducing random individual effects. The estimators are built by expanding the mixed pixels trajectories with B-splines functions and maximizing the log-likelihood with a backfitting-ECME algorithm. A BLUP formula allows then to get the ‘best possible’ estimations of the local temporal responses of each crop when observing mixed pixels trajectories. We show that this model has many potential applications in remote sensing, and an interesting one consists of coupling high and low spatial resolution images in order to perform temporal interpolation of high spatial resolution images (20 m), increasing the knowledge on particular crops in very precise locations.

The unmixing and temporal high-resolution interpolation approaches are illustrated on remote-sensing data obtained on the South-Western France during the year 2002.     

农村边远山区音乐教师发展困境与对策——以四川省农村中小学校为例

我国农村边远山区中小学校由于地处偏远、经济基础差、信息闭塞，加上师资力量薄弱等原因严重影响了学生素质的提高。如何支持农村教师发展，提高农村边远山区中小学教学质量，是当前亟待解决的重大问题。为此，本课题组以农村边远山区音乐教学为切入点，以问卷调研与实地考察相结合的方式，研究农村边远山区中小学音乐教育现状、教师专业情况以及教师培训需求，在此基础上提出对策建议，希望能对农村边远山区教师专业发展走出困境具有参考价值。     

Salmonella Enteritidis Surveillance by Egg Immunology: Impact of the Sampling Scheme on the Release of Contaminated Table Eggs

Design of surveillance programs to detect infections could benefit from more insight into sampling schemes. We address the effect of sampling schemes for Salmonella Enteritidis surveillance in laying hens. Based on experimental estimates for the transmission rate in flocks, and the characteristics of an egg immunological test, we have simulated outbreaks with various sampling schemes, and with the current boot swab program with a 15‐week sampling interval. Declaring a flock infected based on a single positive egg was not possible because test specificity was too low. Thus, a threshold number of positive eggs was defined to declare a flock infected, and, for small sample sizes, eggs from previous samplings had to be included in a cumulative sample to guarantee a minimum flock level specificity. Effectiveness of surveillance was measured by the proportion of outbreaks detected, and by the number of contaminated table eggs brought on the market. The boot swab program detected 90% of the outbreaks, with 75% fewer contaminated eggs compared to no surveillance, whereas the baseline egg program (30 eggs each 15 weeks) detected 86%, with 73% fewer contaminated eggs. We conclude that a larger sample size results in more detected outbreaks, whereas a smaller sampling interval decreases the number of contaminated eggs. Decreasing sample size and interval simultaneously reduces the number of contaminated eggs, but not indefinitely: the advantage of more frequent sampling is counterbalanced by the cumulative sample including less recently laid eggs. Apparently, optimizing surveillance has its limits when test specificity is taken into account.     

赤潮监测系统的优化设计与实验研究

提出一种新型的实时赤潮监测系统的设计方案,通过数据采集、信号处理、无线传输实现海洋水文情况的远程监控功能。对其进行信号采集处理电路、上下位机软件、GPRS无线远程信号传输的优化设计,根据设计原理实现了样机开发,并在玉环海洋观测站进行了海域实验,验证了系统的适用性。此系统可在任意GPRS网络覆盖点接收数据,对影响赤潮发生的海洋水质情况进行实时监测,为相关部门采取预防措施提供数据支持。     

从“欧典地板事件”看监督责任的缺位

由于监督责任的缺位,导致一家没有注册过的“欧典”企业竟然公开通过虚假宣传和欺诈行为严重损害公众利益“。欧典事件”说明,监督责任的缺位是导致企业违法和政府失职的主要原因,其最终结果是政府公信力的破坏和公众利益的损害。因此,进一步通过建立健全包括公民责任和政府责任这两大责任体系的监督责任制度以确保公共利益的维护和实现就显得尤为迫切和必要。     

对我国深山区移民扶贫成本的社会学分析--以江西省遂川县为例

移民扶贫不单纯是一项经济工作,它是一项复杂的社会系统工程,对移民扶贫成本的分析是移民可行性的重要依据。移民成本应包括经济成本、心理成本、环境成本和文化成本等,任何一方面的成本过高,都会影响移民扶贫的有效性。我国的贫困人口分布在全国集中连片的几个地区,移民扶贫在不同地区有不同的表现形式,其成本也不尽相同。忽略移民成本这一客观事实,任何主观善良愿望的移民扶贫决策都难以取得理想的结果。通过对江西省遂川县深山区移民扶贫的成本问题分析,认为扶贫移民不仅要考虑经济成本,还要考虑环境成本,要把心理成本、文化成本降到最低,在移民扶贫过程中忽视传统文化,对人的心理造成伤害的移民决策是不慎重的。     

董事与股份公司利益冲突论略

董事(会)在股份公司中执掌经营决策和业务执行权力。当董事利益与公司利益发生冲突时,董事往往会将其个人利益凌驾于公司利益之上,主要表现为董事违反竞业禁止义务、自我交易、篡夺公司机会等形态。为了防止董事滥权,保护公司利益,需要构建事前、事中和事后抑制机制,对董事职权的行使进行有效监督和规范。     

网络课件的开发系统研究

多媒体技术和网络技术的飞速发展和全面应用,引起了教育方法和手段的深刻变革。本文从网络课件的信息结构特点出发,对该系统的实现作出了系统分析和实现原型。     

Elements of surveillance: A new framework and future directions

This article argues for a wider conceptualization of the meaning and significance of surveillance in contemporary social studies. It has been written in the context of recently published work by Lyon (2001, 2002) who establishes a powerful argument illuminating the social and technical interconnectedness of surveillance systems, and the invisibility of their social ordering effects, in everyday life. The article is divided into two parts. The first examines recent empirical work concerning two domains of surveillance practice, which are significant, and typical of the research findings in these areas of study. The first surveillance practice is that of CCTV in public space, and the second is that which occurs in the workplace. The second part, mindful of Lyon's (2001, 2002) arguments, analyses the recently published work to examine broader ways in which we might want to conceptualize surveillance. It argues that it comprises four elements: representation, meaning, manipulation and intermediation which interact to form 'surveillance domains', and, at a local level, are contested, politicized places. Highlighting the role of intermediation, it uses this framework as the basis of an applied research strategy into everyday surveillance practices.     

Some statistical aspects of methods for detection of turning points in business cycles

Methods for online turning point detection in business cycles are discussed. The statistical properties of three likelihood-based methods are compared. One is based on a Hidden Markov Model, another includes a non-parametric estimation procedure and the third combines features of the other two. The methods are illustrated by monitoring a period of the Swedish industrial production. Evaluation measures that reflect timeliness are used. The effects of smoothing, seasonal variation, autoregression and multivariate issues on methods for timely detection are discussed.