地球剖分网格作为传统地理坐标参考的有效补充,具有形状近似、空间无缝不重叠、尺度连续、全球统一的刚性定位等优势,与REST(Representational State Transfer)Web服务的结合可完成空间区域位置标识下的影像数据互操作。基于此,本研究...地球剖分网格作为传统地理坐标参考的有效补充,具有形状近似、空间无缝不重叠、尺度连续、全球统一的刚性定位等优势,与REST(Representational State Transfer)Web服务的结合可完成空间区域位置标识下的影像数据互操作。基于此,本研究基于地球剖分网格探索遥感影像数据REST资源化方法,定义了面向资源架构(Resource-Oriented Architecture,ROA)的URI标识模型,从面向资源的角度设计互操作协议函数,采用地球剖分网格单元的地址编码代替传统地理坐标以刚性定位资源化影像。最后,以北斗网格作为参考网格,开发分析就绪(Analysis-Ready)资源化影像服务原型系统,并开展互操作案例研究,验证了影像数据资源刚性定位互操作模型用于影像资源共享互操作的可行性和有效性。展开更多
针对无线传感器网络占空比MAC协议在链路或节点失效环境下易导致严重的能量浪费问题,提出了一种基于Grid Quorum的异步低占空比M AC协议-AGQ-M AC(Asynchronous Grid Quorum M AC).AGQ-M AC采用Grid Quorum组分配信道,通过动态调配Quoru...针对无线传感器网络占空比MAC协议在链路或节点失效环境下易导致严重的能量浪费问题,提出了一种基于Grid Quorum的异步低占空比M AC协议-AGQ-M AC(Asynchronous Grid Quorum M AC).AGQ-M AC采用Grid Quorum组分配信道,通过动态调配Quorum比率得到了节点的最优占空比,并在邻节点发现过程中采用双前导序文抽样来监测信道状态,以减少节点唤醒时间从而达到能量高效.仿真实验结果表明,与其他占空比MAC协议相比,AGQ-MAC延长了网络生存时间,降低了网络能耗,提高了邻发现数据传输率,同时保持较低的平均邻发现延迟.展开更多
In order to incorporate smart elements into distribution networks at ITELCA laboratories in Bogotá-Colombia, a Machine-to-Machine-based solution has been developed. This solution aids in the process of low-cost e...In order to incorporate smart elements into distribution networks at ITELCA laboratories in Bogotá-Colombia, a Machine-to-Machine-based solution has been developed. This solution aids in the process of low-cost electrical fault location, which contributes to improving quality of service, particularly by shortening interruption time spans in mid-voltage grids. The implementation makes use of MQTT protocol with an intensive use of Internet of things (IoT) environment which guarantees the following properties within the automation process: Advanced reports and statistics, remote command execution on one or more units (groups of units), detailed monitoring of remote units and custom alarm mechanism and firmware upgrade on one or more units (groups of units). This kind of implementation is the first one in Colombia and it is able to automatically recover from an N-1 fault.展开更多
Service grids possess the features of intelligence and automation to compose heterogeneous resources and will be a commercial focus in network economy pattern. However, service grid business is loosely-coupled, distri...Service grids possess the features of intelligence and automation to compose heterogeneous resources and will be a commercial focus in network economy pattern. However, service grid business is loosely-coupled, distributed and long-running, so there is a real challenge for the researchers to provide consistency and reliability for service grid business. This paper references the transaction management methods in Web service and the safepoint concept in workflow system, combines with the feature of the service grid, and then presents a transaction management model based on service grid. This model guarantees the robustness of grid service composition and assures that service grid enabling system provides consistent and reliable results for the consumers. Key words service grid - transaction - coordination framework - coordination protocol - recovery - salepoint CLC number TP 393 Foundation item: Supported by the High Technology Research and Development Program of China (2003AA414210) and National Natural Science Foundation of China (60173051)Biography: CHEN Xiang-yu (1979-), female, Master candidate, research direction: Web service, grid, distributed system.展开更多
文摘地球剖分网格作为传统地理坐标参考的有效补充,具有形状近似、空间无缝不重叠、尺度连续、全球统一的刚性定位等优势,与REST(Representational State Transfer)Web服务的结合可完成空间区域位置标识下的影像数据互操作。基于此,本研究基于地球剖分网格探索遥感影像数据REST资源化方法,定义了面向资源架构(Resource-Oriented Architecture,ROA)的URI标识模型,从面向资源的角度设计互操作协议函数,采用地球剖分网格单元的地址编码代替传统地理坐标以刚性定位资源化影像。最后,以北斗网格作为参考网格,开发分析就绪(Analysis-Ready)资源化影像服务原型系统,并开展互操作案例研究,验证了影像数据资源刚性定位互操作模型用于影像资源共享互操作的可行性和有效性。
文摘针对无线传感器网络占空比MAC协议在链路或节点失效环境下易导致严重的能量浪费问题,提出了一种基于Grid Quorum的异步低占空比M AC协议-AGQ-M AC(Asynchronous Grid Quorum M AC).AGQ-M AC采用Grid Quorum组分配信道,通过动态调配Quorum比率得到了节点的最优占空比,并在邻节点发现过程中采用双前导序文抽样来监测信道状态,以减少节点唤醒时间从而达到能量高效.仿真实验结果表明,与其他占空比MAC协议相比,AGQ-MAC延长了网络生存时间,降低了网络能耗,提高了邻发现数据传输率,同时保持较低的平均邻发现延迟.
文摘In order to incorporate smart elements into distribution networks at ITELCA laboratories in Bogotá-Colombia, a Machine-to-Machine-based solution has been developed. This solution aids in the process of low-cost electrical fault location, which contributes to improving quality of service, particularly by shortening interruption time spans in mid-voltage grids. The implementation makes use of MQTT protocol with an intensive use of Internet of things (IoT) environment which guarantees the following properties within the automation process: Advanced reports and statistics, remote command execution on one or more units (groups of units), detailed monitoring of remote units and custom alarm mechanism and firmware upgrade on one or more units (groups of units). This kind of implementation is the first one in Colombia and it is able to automatically recover from an N-1 fault.
文摘Service grids possess the features of intelligence and automation to compose heterogeneous resources and will be a commercial focus in network economy pattern. However, service grid business is loosely-coupled, distributed and long-running, so there is a real challenge for the researchers to provide consistency and reliability for service grid business. This paper references the transaction management methods in Web service and the safepoint concept in workflow system, combines with the feature of the service grid, and then presents a transaction management model based on service grid. This model guarantees the robustness of grid service composition and assures that service grid enabling system provides consistent and reliable results for the consumers. Key words service grid - transaction - coordination framework - coordination protocol - recovery - salepoint CLC number TP 393 Foundation item: Supported by the High Technology Research and Development Program of China (2003AA414210) and National Natural Science Foundation of China (60173051)Biography: CHEN Xiang-yu (1979-), female, Master candidate, research direction: Web service, grid, distributed system.
