Due to the restricted satellite payloads in LEO mega-constellation networks(LMCNs),remote sensing image analysis,online learning and other big data services desirably need onboard distributed processing(OBDP).In exist...Due to the restricted satellite payloads in LEO mega-constellation networks(LMCNs),remote sensing image analysis,online learning and other big data services desirably need onboard distributed processing(OBDP).In existing technologies,the efficiency of big data applications(BDAs)in distributed systems hinges on the stable-state and low-latency links between worker nodes.However,LMCNs with high-dynamic nodes and long-distance links can not provide the above conditions,which makes the performance of OBDP hard to be intuitively measured.To bridge this gap,a multidimensional simulation platform is indispensable that can simulate the network environment of LMCNs and put BDAs in it for performance testing.Using STK's APIs and parallel computing framework,we achieve real-time simulation for thousands of satellite nodes,which are mapped as application nodes through software defined network(SDN)and container technologies.We elaborate the architecture and mechanism of the simulation platform,and take the Starlink and Hadoop as realistic examples for simulations.The results indicate that LMCNs have dynamic end-to-end latency which fluctuates periodically with the constellation movement.Compared to ground data center networks(GDCNs),LMCNs deteriorate the computing and storage job throughput,which can be alleviated by the utilization of erasure codes and data flow scheduling of worker nodes.展开更多
CORBA specification and technique stemmed from 1991. It has had rapid development and wide applications in the past few yeals. This paper introduces the development of CORBA at first. Then it points out several CORBA ...CORBA specification and technique stemmed from 1991. It has had rapid development and wide applications in the past few yeals. This paper introduces the development of CORBA at first. Then it points out several CORBA technical characteristics such as broker mechanism, separation of client and server and independence of implementation environment. It also analyses thedifferences between CORBA and traditional distributed processing techniques, for instance RPC and DCE. It summarizes typical successful CORBA applications in various fields, its main products and its tendency. The paper illustrates the general usage of CORBA technique, too.展开更多
As one of the popular interoperability technology, CORBA provides a distributed computing environmentfor enterprise application system. Although CORBA makes the development of the distributed S application moreconveni...As one of the popular interoperability technology, CORBA provides a distributed computing environmentfor enterprise application system. Although CORBA makes the development of the distributed S application moreconvenient and rapid, it does not define a separate process management service to manage and control the server pro-cesses of the ORB domain. Conforming to the CORBA 2. x specification, this paper analyzes the features and the ba-sic mechanisms of the process deployment for cluster servers in the distributed computing environment, and presentsa design of process management model by integrating SAD and SMD. In particular, the dynamic extension technologyand how SMD locates- SAD are also discussed in the paper.展开更多
基金supported by National Natural Sciences Foundation of China(No.62271165,62027802,62201307)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030297)+2 种基金the Shenzhen Science and Technology Program ZDSYS20210623091808025Stable Support Plan Program GXWD20231129102638002the Major Key Project of PCL(No.PCL2024A01)。
文摘Due to the restricted satellite payloads in LEO mega-constellation networks(LMCNs),remote sensing image analysis,online learning and other big data services desirably need onboard distributed processing(OBDP).In existing technologies,the efficiency of big data applications(BDAs)in distributed systems hinges on the stable-state and low-latency links between worker nodes.However,LMCNs with high-dynamic nodes and long-distance links can not provide the above conditions,which makes the performance of OBDP hard to be intuitively measured.To bridge this gap,a multidimensional simulation platform is indispensable that can simulate the network environment of LMCNs and put BDAs in it for performance testing.Using STK's APIs and parallel computing framework,we achieve real-time simulation for thousands of satellite nodes,which are mapped as application nodes through software defined network(SDN)and container technologies.We elaborate the architecture and mechanism of the simulation platform,and take the Starlink and Hadoop as realistic examples for simulations.The results indicate that LMCNs have dynamic end-to-end latency which fluctuates periodically with the constellation movement.Compared to ground data center networks(GDCNs),LMCNs deteriorate the computing and storage job throughput,which can be alleviated by the utilization of erasure codes and data flow scheduling of worker nodes.
文摘CORBA specification and technique stemmed from 1991. It has had rapid development and wide applications in the past few yeals. This paper introduces the development of CORBA at first. Then it points out several CORBA technical characteristics such as broker mechanism, separation of client and server and independence of implementation environment. It also analyses thedifferences between CORBA and traditional distributed processing techniques, for instance RPC and DCE. It summarizes typical successful CORBA applications in various fields, its main products and its tendency. The paper illustrates the general usage of CORBA technique, too.
文摘As one of the popular interoperability technology, CORBA provides a distributed computing environmentfor enterprise application system. Although CORBA makes the development of the distributed S application moreconvenient and rapid, it does not define a separate process management service to manage and control the server pro-cesses of the ORB domain. Conforming to the CORBA 2. x specification, this paper analyzes the features and the ba-sic mechanisms of the process deployment for cluster servers in the distributed computing environment, and presentsa design of process management model by integrating SAD and SMD. In particular, the dynamic extension technologyand how SMD locates- SAD are also discussed in the paper.
