Mapping wildfire and clearcut harvest disturbances in boreal forests with Landsat time series data

Information regarding the extent, timing and magnitude of forest disturbance are key inputs required for accurate estimation of the terrestrial carbon balance. Equally important for studying carbon dynamics is the ability to distinguish the cause or type of forest disturbance occurring on the landscape. Wildfire and timber harvesting are common disturbances occurring in boreal forests, with each having differing carbon consequences (i.e., biomass removed, recovery rates). Development of methods to not only map, but distinguish these types of disturbance with satellite data will depend upon an improved understanding of their distinctive spectral properties. In this study, we mapped wildfires and clearcut harvests occurring in a Landsat time series (LTS) acquired in the boreal plains of Saskatchewan, Canada. This highly accurate reference map (kappa = 0.91) depicting the year and cause of historical disturbances was used to determine the spectral and temporal properties needed to accurately classify fire and clearcut disturbances. The results showed that spectral data from the short-wave infrared (SWIR; e.g., Landsat band 5) portion of the electromagnetic spectrum was most effective at separating fires and clearcut harvests possibly due to differences in structure, shadowing, and amounts of exposed soil left behind by the two disturbance types. Although SWIR data acquired 1 year after disturbance enabled the most accurate discrimination of fires and clearcut harvests, good separation (e.g., kappa ≥ 0.80) could still be achieved with Landsat band 5 and other SWIR-based indices 3 to 4 years after disturbance. Conversely, minimal disturbance responses in near infrared-based indices associated with green leaf area (e.g., NDVI) led to unreliably low classification accuracies regardless of time since disturbance. In addition to exploring the spectral and temporal manifestation of forest disturbance types, we also demonstrate how Landsat change maps which attribute cause of disturbance can be used to help elucidate the social, ecological and carbon consequences associated with wildfire and clearcut harvesting in Canadian boreal forests.     

基于免疫网络的异态电磁信号监测模型

针对人工免疫系统运用于信号密度适中的日常异态信号监测时,系统对检测器数量要求过高的问题,本文对现有的模型进行了改进,提出了基于免疫网络的异态电磁信号监测模型。模型引入数据正向压缩和检测器相互抑制的机制,使得系统对检测器数量的要求明显降低。本文采用实际无线电监测数据对模型进行了检验,并与基于阴性选择的模型进行对比,验证了该模型在信号密度适中的日常监测中可大幅减少对检测器数量的要求,提高了监测效率。     

基于ZigBee的生产线监控系统的设计与实现

根据生产线的实际需要,设计并实现了用于生产线的无线信息传输网络节点,研究了系统结构,完成了系统的软硬件设计,详细分析了ZigBee组网通信、应答机制建立等关键技术。测试结果表明,系统传输距离远、可靠性高,能够满足实际应用需要。     

低浓度瓦斯管道输送安全监控系统研究

随着低浓度瓦斯利用进度的加快,对于跨越5%～16%爆炸范围的低浓度瓦斯输送安全问题凸显,为保障低浓度瓦斯的安全输送和利用特研发了该套低浓度瓦斯管道输送安全监控系统。介绍了系统结构及工作原理,主要控制设备设计思路,软件及通讯单元设计思路。试验表明该系统能在低浓度瓦斯输送管道发生爆炸、燃烧等危险出现时能及时响应,有效阻止灾害扩大,保障低浓度瓦斯安全输送。     

基于PLC的天然气发电机组监控系统设计

通过对现行天然气发电机组监控系统的调查和研究,设计了以PLC为主导的天然气发电机组监控系统,系统选用PLC来实现对系统的监控,并辅以组态软件实现系统的上位PC机监控。该系统是一种采集精度、分辨率高、采集速度快、可靠性高、功能强大、维护方便的天然气发电机组监控系统。     

手持式电站锅炉配风监测仪的设计

针对当前电站锅炉燃烧器的现场巡视、检修设备的溃乏,研制一种手持式电站锅炉配风监测仪势在必行。基于在了解电站锅炉煤粉配风监测系统的工作原理以及测量工作原理的基础上,首先采用经标定过的测速元件测量,经差压变速器送到测量装置内部的压力传感器变送测量出动压;其次由测速原理可以计算出风速;再次由三支分别用于测量热风温度、煤粉温度和风粉混合温度的铂电阻传感器所测得的温度值,根据热平衡原理计算出煤粉浓度。重点介绍了基本设计电路硬件结构以及关键低功耗电路设计,既给出了监测仪主程序软件流程图,又给出了电站锅炉配风仪动压测量的结果分析,达到了设计的要求。经电厂技术人员试验证明,运行可靠,使用方便,成本低,有较高的推广价值。     

广播电视发射机控制软件特殊故障分析

广播电视发射机控制软件的应用提高了设备运行的监测质量,减轻了值班的劳动强度,系统集成的数据采集及数据整理功能增强了设备运行分析,工程技术人员可以根据统计数据准确判断设备运行以及故障情况。文章针对监控软件在运行过程中出现的特例故障现象提出了故障原因及解决方法。     

基于RS485总线的监控系统研究与设计

PID调节仪表与传感器配合使用,可以实现对钢制品生产线上罩式炉温度的测量与显示。通过相应的执行器,可以实现对相关罩式炉设备的PID调节和控制、报警控制、数据采集和记录。然而对于具备多条生产线,而每条生产线使用多个PID调节仪表的现场环境而言,依次对每个仪表进行操作并不方便。采用Borland C++Builder 6设计了PID调节仪表的在线集中监控系统。,利用Borland C++Builder 6功能强大的图形化控制界面,及SPComm控件在串行口下编程,通过USB转RS485协议转换器,很好地实现了对生产线上各个分区仪表的实时监测与远程控制。     

监控平台软件的功能及设计实例

分析了用于生产过程监测系统组态软件包的功能,并按此设计一个基于Ｗｉｎｄｏｗｓ ＮＴ的系统组态软件,该软件具有功能齐全的作图工具库,灵活的通信联网能力与数据交换接口。     

基于进程管理的气象文件监控处理

文件实时监控处理过程在控制程序处理过程中被广泛运用。本文结合文件处理的实际工作,描述了文件处理程序的监控处理过程,实现了基于进程管理的文件监控处理与预处理过程的协同工作。