针对目前用水单位地理位置分布分散、难以实现对其用水量实时监测的特点,设计了采用GPRS(General Packet Rad io Service)无线传输技术的水资源远程监控系统。该系统使用.NET技术实现,系统结构为B/S三层结构,由数据采集模块、无线传输...针对目前用水单位地理位置分布分散、难以实现对其用水量实时监测的特点,设计了采用GPRS(General Packet Rad io Service)无线传输技术的水资源远程监控系统。该系统使用.NET技术实现,系统结构为B/S三层结构,由数据采集模块、无线传输模块和信息处理模块组成。文中详细介绍了系统工作原理、硬件配置和软件设计。实践证明,该系统具有可靠性高、网络覆盖范围广、传输速度快的特点。展开更多
The problem of constructing a Petri net feedback controller, which enforces the conjunction of a set of linear inequalities on the reachable marking of the place and transition modeled by Petri net, is discussed. A ne...The problem of constructing a Petri net feedback controller, which enforces the conjunction of a set of linear inequalities on the reachable marking of the place and transition modeled by Petri net, is discussed. A new method of controller design with mixed constraint is presented, and a net reduction technique of Petri net fuses all the constrained places into one place whose marking is equal to the sum of the markings of the constrained places, and then compared with the constrained transitions. The net reduction eases the design of controller and holds remarkable advantages especially for systems with large scale. The method is proved to be simpler and more efficient than the method presented by Yamalidou, et al, using an applied case used by Yamalidou, et al.展开更多
针对电力系统传统的采用C/S结构的生产管理系统程序复杂、资源占用多、安全隐患大、效率低的缺点,基于工作流技术提出了一种三层B/S结构的电力生产协同组织管理系统的设计与实现方法。该系统运行于微软.NET平台,以SQL Server 2000作为...针对电力系统传统的采用C/S结构的生产管理系统程序复杂、资源占用多、安全隐患大、效率低的缺点,基于工作流技术提出了一种三层B/S结构的电力生产协同组织管理系统的设计与实现方法。该系统运行于微软.NET平台,以SQL Server 2000作为后台数据库服务器,以ASP.NET组件ADO.NET访问数据库,实现了电力系统内部生产组织的网上管理自动化,在减轻员工工作负担、提高工作效率及信息交流方面都发挥了重要的作用。展开更多
We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis sys...We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis system. Measurement of forest microclimate was conducted simultaneously and a model was found for the relationship of soil, stem, leaf and climate factors. CO2 flux of different components in ecosystem of the broad-leaved Korean pine forest was estimated based on vegetation characteristics. The net ecosystem exchange was measured by eddy covariance technique. And we studied the effect of temperature and photosynthetic active radiation on ecosystem CO2 flux. Through analysis we found that the net ecosystem exchange was affected mainly by soil respiration and leaf photosynthesis. Annual net ecosystem exchange ranged from a minimum of about -4.671μmol·m-2·s-1 to a maximum of 13.80μmol·m-2·s-1, mean net ecosystem exchange of CO2 flux was -2.0μmol·m-2·s-1 and 3.9μmol·m-2·s-1 in winter and summer respectively (mean value during 24 h). Primary productivity of tree, shrub and herbage contributed about 89.7%, 3.5% and 6.8% to the gross primary productivity of the broad-leaved Korean pine forest respectively. Soil respiration contributed about 69.7% CO2 to the broad-leaved Korean pine forest ecosystem, comprising about 15.2% from tree leaves and 15.1% from branches. The net ecosystem exchange in growing season and non-growing season contributed 56.8% and 43.2% to the annual CO2 efflux respectively. The ratio of autotrophic respiration to gross primary productivity (Ra:GPP) was 0.52 (NPP:GPP=0.48). Annual carbon accumulation underground accounted for 52% of the gross primary productivity, and soil respiration contributed 60% to gross primary productivity. The NPP of the needle and broad-leaved Korean pine forest was 769.3 gC·m-2·a-1. The net ecosystem exchange of this forest ecosystem (NEE) was 229.51 gC·m-2·a-1. The NEE of this forest ecosystem acquired by eddy covariance technique was lower than 展开更多
文摘针对目前用水单位地理位置分布分散、难以实现对其用水量实时监测的特点,设计了采用GPRS(General Packet Rad io Service)无线传输技术的水资源远程监控系统。该系统使用.NET技术实现,系统结构为B/S三层结构,由数据采集模块、无线传输模块和信息处理模块组成。文中详细介绍了系统工作原理、硬件配置和软件设计。实践证明,该系统具有可靠性高、网络覆盖范围广、传输速度快的特点。
文摘The problem of constructing a Petri net feedback controller, which enforces the conjunction of a set of linear inequalities on the reachable marking of the place and transition modeled by Petri net, is discussed. A new method of controller design with mixed constraint is presented, and a net reduction technique of Petri net fuses all the constrained places into one place whose marking is equal to the sum of the markings of the constrained places, and then compared with the constrained transitions. The net reduction eases the design of controller and holds remarkable advantages especially for systems with large scale. The method is proved to be simpler and more efficient than the method presented by Yamalidou, et al, using an applied case used by Yamalidou, et al.
文摘针对电力系统传统的采用C/S结构的生产管理系统程序复杂、资源占用多、安全隐患大、效率低的缺点,基于工作流技术提出了一种三层B/S结构的电力生产协同组织管理系统的设计与实现方法。该系统运行于微软.NET平台,以SQL Server 2000作为后台数据库服务器,以ASP.NET组件ADO.NET访问数据库,实现了电力系统内部生产组织的网上管理自动化,在减轻员工工作负担、提高工作效率及信息交流方面都发挥了重要的作用。
基金This work was supported by the Chi-nese Academy of Sciences and the Ministry of Science and Technology (Grant No. KZCX1-SW01-01B) the Na-tional Natural Science Foundation of China (Grant No. 30271068) and Institute of Applied Ecology, CAS.
文摘We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis system. Measurement of forest microclimate was conducted simultaneously and a model was found for the relationship of soil, stem, leaf and climate factors. CO2 flux of different components in ecosystem of the broad-leaved Korean pine forest was estimated based on vegetation characteristics. The net ecosystem exchange was measured by eddy covariance technique. And we studied the effect of temperature and photosynthetic active radiation on ecosystem CO2 flux. Through analysis we found that the net ecosystem exchange was affected mainly by soil respiration and leaf photosynthesis. Annual net ecosystem exchange ranged from a minimum of about -4.671μmol·m-2·s-1 to a maximum of 13.80μmol·m-2·s-1, mean net ecosystem exchange of CO2 flux was -2.0μmol·m-2·s-1 and 3.9μmol·m-2·s-1 in winter and summer respectively (mean value during 24 h). Primary productivity of tree, shrub and herbage contributed about 89.7%, 3.5% and 6.8% to the gross primary productivity of the broad-leaved Korean pine forest respectively. Soil respiration contributed about 69.7% CO2 to the broad-leaved Korean pine forest ecosystem, comprising about 15.2% from tree leaves and 15.1% from branches. The net ecosystem exchange in growing season and non-growing season contributed 56.8% and 43.2% to the annual CO2 efflux respectively. The ratio of autotrophic respiration to gross primary productivity (Ra:GPP) was 0.52 (NPP:GPP=0.48). Annual carbon accumulation underground accounted for 52% of the gross primary productivity, and soil respiration contributed 60% to gross primary productivity. The NPP of the needle and broad-leaved Korean pine forest was 769.3 gC·m-2·a-1. The net ecosystem exchange of this forest ecosystem (NEE) was 229.51 gC·m-2·a-1. The NEE of this forest ecosystem acquired by eddy covariance technique was lower than
