A method for integrating MODIS and Landsat data for systematic monitoring of forest cover and change in the Congo Basin

In this paper we demonstrate a new approach that uses regional/continental MODIS (MODerate Resolution Imaging Spectroradiometer) derived forest cover products to calibrate Landsat data for exhaustive high spatial resolution mapping of forest cover and clearing in the Congo River Basin. The approach employs multi-temporal Landsat acquisitions to account for cloud cover, a primary limiting factor in humid tropical forest mapping. A Basin-wide MODIS 250 m Vegetation Continuous Field (VCF) percent tree cover product is used as a regionally consistent reference data set to train Landsat imagery. The approach is automated and greatly shortens mapping time. Results for approximately one third of the Congo Basin are shown. Derived high spatial resolution forest change estimates indicate that less than 1% of the forests were cleared from 1990 to 2000. However, forest clearing is spatially pervasive and fragmented in the landscapes studied to date, with implications for sustaining the region's biodiversity. The forest cover and change data are being used by the Central African Regional Program for the Environment (CARPE) program to study deforestation and biodiversity loss in the Congo Basin forest zone. Data from this study are available at http://carpe.umd.edu.     

Mapping the potential annual total nitrogen load in the river basins of Japan with remotely sensed imagery

The increase of nutrient loads such as nitrogen and phosphorus to a river due to land cover changes in surrounding areas has been one of the major sources of water pollution or eutrophication. Monitoring the influent nutrient load from river basins to rivers is now crucial in the management of river basin environments. The monitoring is not easy, however, because it requires spatial and temporal measurement tools for land cover changes in the river basin and water qualities, and also it requires models relating them.In this study, we first analyzed the relation between the land cover types estimated from monthly maximum Normalized Difference Vegetation Index (NDVI) imagery calculated from NOAA Advanced Very High Resolution Radiometer (AVHRR) imagery and the annual total nitrogen load discharged from river basins. We found that the runoff load factor from urban areas is higher than those of forested areas. We also found that the impacts of land cover such as plantation and field weed communities on the total nitrogen load of each river are higher than the impacts of other land cover types such as Beech and Camellia japonica community type.Finally, we produced two advanced maps of the potential annual total nitrogen load (PTNL) index and the potential annual total nitrogen load for each river basin area (PTNL/area) index by considering the relationship between the land cover types and the annual total nitrogen load discharged from river basins in Japan. The PTNL map will be useful for the risk assessment of total nitrogen load impact on lakes and the sea through rivers from each basin. The PTNL/area index, which considers the effects of river basin areas, will allow evaluation of the state of river basins.     

On-Line Monitoring of Large Petri Net Models Under Partial Observation

We consider a Petri Net model of the plant. The observation is given by a subset of transitions whose occurrence is always and immediately sensed by a monitoring agent. Other transitions not in this subset are silent (unobservable). Classical on-line monitoring techniques, which are based on the estimation of the current state of the plant and the detection of the occurrence of undesirable events (faults), are not suitable for models of large systems due to high spatial complexity (exponential in the size of the entire model). In this paper we propose a method based on the explanation of plant observation. A legal trace minimally explains the observation if it includes all unobservable transitions whose firing is needed to enable the observed transitions. To do so, starting from an observable transition, using backward search techniques, a set of minimal explanations is derived, which are sufficient for detecting whether a fault event must have occurred for sure in the plant or not. The technique also allows production of a set of basis markings for the estimation of the current state of the plant. The set of all possible current markings can then be characterized as the unobservable reach of these basis markings. The computational complexity of the algorithm depends on the size of the largest connected subnet which includes only unobservable transitions. This allows monitoring of plants of any size in which there is no large unobservable subnet. We also illustrate the applicability of the method for the monitoring of a class of infinite state systems, unbounded Petri Nets with unobservable trap circuits, and we show how this can be useful for distributed implementations.

天津市中心城区泵站在线监测系统常见问题及解决方法初探

根据近两年天津市中心城区泵站在线监测系统管理工作的经验,归纳了其在采样、分析、数据采集传输和运行维护等方面常见的问题,进行分析并提出解决方法,为运行维护提供参考,有利于泵站在线监测系统的应用。     

C#实现连续读写射频卡的两种方法比较

由于软件项目的需要,要实现这样一个功能:读卡器连续自动读卡,并将读出的数据记录在数据库,修改卡上的信息,一直到手动停止.要实现这样的功能,有两种方法,一种是委托监听,另外一种是循环读卡,介绍这两种方法,并对比这两种方法的优劣.项目所使用的是串口的IC卡读写器,读卡器有两种接口,一种是USB,另一种是RS-232的标准串口.     

多星座全球导航卫星系统完整性分析

在未来多星座双频情况下,对全球导航卫星系统提供的全球服务的完整性进行仿真分析,设计多星座的模拟环境,采用奇偶向量法进行完整性计算,从而获得全球VPL的分布情况。仿真实验结果表明,与现有全球定位系统提供的标准定位服务相比,该系统提供的服务的完整性更高,能够达到民航LPV-200级别的完整性要求。     

基于蜜罐技术的安全校园网的设计与实现

蜜罐是一种安全资源,其价值在于被扫描、攻击和攻陷并对这些攻击活动进行监视、检测和分析。本文提出了一种新的基于蜜罐技术的校园网络安全解决方案。根据蜜罐技术的原理结合校园网现实状况编写出便于校园网安装和实现的微型蜜罐系统。在保证主机安全的前提下,实现了蜜罐的数据捕获、分析功能。     

基于行为特征的安全运营监测平台设计与实现

在安全运营平台的建设中,通过行为特征而构建的主动发现预警机制,将会成为监测并能够发现网络中各种安全隐患、违规行为的一种独特的设计思路和实现方法.从基于安全隐患行为特征的检测、基于为业务数据行为特征的检测两个方面对基于行为特征而构建的安全运营监测系统进行了阐述.     

基于触发器的考核管理信息系统监控模块的设计和实现

在分析SQL Server数据库触发器的类别和功能的基础上,针对考核管理信息系统中用户误操作造成的数据库错误,设计并实现了一种基于触发器的监控模块,通过对用户访问和操作信息的监控和审查,实现单步操作的撤销和单条数据的恢复,提高了数据库的安全性.     

基于VC++工控组态软件的总体设计与实现

针对组态软件的特点和功能,提出了系统的体系结构、模块的划分.着重讨论了在开发监控组态软件系统过程中组态软件的可视化环境开发技术,包括可视化设计端和运行端的建立、组态体系/组态图元的设计、可视化控件的设计以及图形化的控件存取等.