入侵检测技术的现状研究

介绍了入侵检测系统的概念,对现有的入侵检测系统进行了分类,并对入侵检测系统的发展趋势作了预测。     

面向物联网的“嵌入式系统”课程教学改革的探索

在物联网技术的应用中,嵌入式系统起着核心的基础设施作用。在分析物联网对嵌入式系统教学产生巨大影响的基础上,针对嵌入式系统的特点对"嵌入式系统"课程的授课思路和教学方法进行了调整,从分布式控制、节能设计策略、软件工程思维等方面扩展与物联网应用密切的相关知识点,同时对授课方式进行了改革,以满足物联网领域对嵌入式系统人才的需要。     

基于SOA的移动GIS分布式森林监护报警系统研究

在对面向服务架构深入研究的基础上,基于SOA进行分布式监测报警系统体系结构设计,并对森林监护报警系统进行研究,实现森林监护的智能化、分布式管理。将面向服务架构的思想应用到移动GIS森林监护系统中,降低了系统的复杂度和耦合度,提高了系统的适应性,优化了资源利用率,提高了森林监护系统的运行效率。     

森林系统的整体性与复杂性问题的研究

森林系统是陆地生态系统的主体。这个系统是开放的复杂巨系统。它的系统特征 :开放性、非线性、混沌性、突变性、自组织性、不可逆性。远离平衡态的耗散结构 ,综合构成了森林系统的整体性、复杂性。对探讨系统整体性、复杂性的方法论和系统思考问题构思了一个基本框架     

西双版纳热带雨林水文观测系统的设计

讨论了西双版纳热带雨林、人工林和无林地水文观测系统的建设与设计 ,对水文观测系统内实测项目作了介绍 ,还对需要计算的项目也作了简单介绍。该森林水文观测系统设计合理 ,具有可操作性 ,并且大部分监测项目实现了自记记录     

现代智能家居的研究设计

介绍了智能家居发展史和国内外现状,对智能家居系统构成和电力载波技术进行了分析探讨。对智能家居产品做了简要介绍,并选择已有智能家居系统中操作相对简单、用户较易理解的智能家居系统进行设计,将智能家居产品与原有家居环境融为一体,体现出以人为本的家居环境。     

谈ILAS编目系统的应用

介绍了编目系统的特点,对编目系统在实际工作中的应用,以及实现计算机管理进行了探讨。     

浅析常规空调水系统及其运行故障的处理方法

简单介绍水系统的组成、分类、竖向分区等内容,并对水系统运行的常见故障进行了阐述,对空调水系统的基本概念以及空调水系统故障诊断有一定的指导作用。     

大型公共建筑空调系统的节能控制

针对大型公共建筑中央空调系统能耗在建筑能耗中所占的比重越来越大的现象,对长沙市的一些大型公共建筑进行了的调研,运用全建筑能耗模拟软件EnergyPlus对某商场进行了能耗模拟,对其模拟结果与调研结果进行了比较与分析,提出了运用自动控制系统来实现公共建筑空调系统的节能的建议。     

VAV耦合VWV系统的能耗分析与节能研究

以中央空调VAV系统及VWV系统为研究对象,从节能角度及能耗方面对该系统与传统CAV系统及CWV系统进行应用对比分析。研究了目前中央空调VAV系统耦合VWV系统的应用特点。并针对实际工程利用能耗模拟软件对VAV系统、VWV系统、CAV系统及CWV系统相互耦合的能耗逐一进行对比,总结相关系统耦合的节能性。并得出VAV系统耦合VWV系统具有很好的节能效果,这是值得深入研究并采用的系统方式。     

林区巡检中GPS手持机与PC机通信的研究

介绍了林区巡检中应用GPS手持机的优点及其通信协议。给出了GPS手持机与PC机的硬件连接框图,详细介绍了PC机读取GPS手持机的软件实现方法,并给出了相应的流程图。     

Nitrogen transfer between N2-fixing plant and non-N2-fixing plant

IntroductionNitrogenisanelementthatcyclesthroughanecosyst6mandneedstobepresentatacertain'minimumIeveItosust8inthatsystem.lnaninterspe-ciesconteXt,thebeneficiaIeff6ctsofN2-fixingpIantsinecosyst6ms,duetOtheirc0ntributionofnitr0gen,havebeenobservedbysucceedinggenerationsofagronomists,f0rest6rs,andecoIogists.Thein-terpIantsofN2-fixingplantsandnon-N2-fixingplantsarepraCticedtoincreasetotaIyieldandreducetheneedfOrf6Ftilizersinput,andithasbeenshownthatpartoftheassimiIatedNinthenon-N2-fixingpIa…     

林区巡检中GPS接收机的设计

以Trimble公司的LassenTMSQ GPS-OEM板为核心,设计了一款专门用于林区巡检的GPS接收机,并给出了林区巡检中GPS接收机的组成框图以及软、硬件的特点。     

eTrex GPS接收机在森林资源调查中的定位精度评估

针对GPS在森林资源调查中的应用现状,主要阐述了手持式GPS接收机的定位精度,并以山东中部的徂徕山林场作为实验区,研究了eTrex手持式GPS接收机和Z-MAX差分GPS接收机观测值的变化规律。     

Nitrogen transfer between N2-fixing plant and non-N2-fixing plant

The transfer mechanisms, calculating methods and ecological significance of nitrogen transfer between legumes and non-legumes are briefly reviewed. There are three pathways of nitrogen transfer from legumes to neighboring non-legumes: (1) the nitrogen pass in soluble form from the donor legume root into the soil solution, move by diffusion or/and mass flow to the receiver root and be taken up by the latter; (2) nitrogen pass into the soil solution as before, be taken up and transported by mycorrhizal hyphae attached to the receiver roots; (3) if mycorrhizal hyphae form connections (bridges) between the two root systems, the nitrogen could pass into the fungus within the donor root and be transported into the receiver root without ever being in the soil solution. The mechanisms of nitrogen transfer between N₂-fixing plants and non-N₂-fixing plants are reviewed in terms of indirect and direct pathways. The indirect N-transfer process is related to the release of nitrogen from legumes (donor plants), the possible interaction of this nitrogen with soil, the decomposition and mineralization of legumes and turnover of nitrogen, the nitrogen absorbing and competing abilities of the legume and the non-legume (receiver plant). The direct nitrogen transfer process is generally considered to be related to the nitrogen gradient and physiological imbalance between legumes and non-legumes, and when the donor legume lies in stressful stage (i.e. removal of shoots or attacked by insects), the nitrogen transfer can be improved significantly. The methods of determining nitrogen transfer (indirect¹⁵N-isotope dilution method and direct¹⁵N determination method) are evaluated, and their advantages and shortcomings are shown in this review. Foundation Item: This paper was funded by National Science Foundation and Doctor Foundation of China. Biography: J{upang} San-na (1970-), male. Ph. doctor, engineer in Collage of Resource and Environment. Beijing Forestry University Responsible editor: Chai Ruihai     

卷叶黄精根不同极性化感物质的化感作用

化感作用是植物通过淋溶、挥发、残茬降解和根系分泌向环境中释放化学物质,从而对自身或周围其他植物的生长产生影响的现象(孔垂华等,2001;董卓杭等,2001;翟明普等,1993;林文雄等,2001;马茂华等,1999;彭少麟等,2001).化感作用普遍存在于自然界,对其深入研究将有利于复合系统中植物配置、耕作制度和栽培措施的科学化,在植物间加强促进作用,降低抑制作用,促进生物多样性和农业可持续发展.     

Effects of polyline simplification of dynamic GPS data under forest canopy on area and perimeter estimations

The objectives of this study were to determine Global Positioning System (GPS) positional errors while moving under the forest canopy and to clarify the effects of polyline simplification on area and perimeter estimations. We used the Pathfinder Pro XR and GPSMAP 76S, which are categorized as “high-end mapping” and “general navigation” GPS receivers, respectively. The field tests were conducted in both natural and plantation forests. The results showed that the Pathfinder Pro XR, which has better multipath rejection technology, worked well, especially in the plantation forest under unfavorable conditions of higher stand density. We used analysis of variance to clarify the effects of the receiver type, positioning mode, stand type, and polyline simplification method on area and perimeter estimations. The receiver type and positioning mode were found to be significant factors that affected area estimation. The Pathfinder Pro XR estimated the area more accurately than the GPSMAP 76S, and differential GPS estimated the area more accurately than autonomous GPS. With respect to the perimeter, the receiver type, positioning mode, and polyline simplification method were found to be significant factors. The results showed that perimeter estimation was improved by using the velocity filter, and further improved by using the velocity filter and Douglas-Peucker algorithm, especially when the Pathfinder Pro XR was used. The GPSMAP 76S estimated the perimeter accurately without any filtering because its default speed filter worked well, even though the GPSMAP 76S is a general navigation GPS receiver.     

GPS手持机在森林资源连续清查中的应用探讨

对手持式GPS接收机在森林资源连续清查中应用方法如:地理坐标参数的获取、计算和设置;在样地初设及复查时的应用作了论述,认为应用其可减少工作量,提高定位精度和复位率,有利于质量管理.     

基于GPS技术的木材采运系统设计

设计了一种基于GPS技术的木材采运系统,并给出了系统总体设计框图.设计了用于木材采运系统的GPS定位接收机,通过AT89C51单片机的控制作用,将定位点的三维信息和测量数据通过液晶显示器显示出来.     

手持型GPS接收机面积测量精度研究

在理论分析手持型GPS接收机面积测量原理的基础上,对9个不同大小地块在不同时段、不同干扰条件下实际面积测量的精度进行分析,详细论证了手持型GPS接收机完全能够满足退耕还林、造林地验收、小班面积测量等精度的需要,可广泛应用于森林资源调查.