企业服务总线(Enterprise Service Bus,ESB)结合事件驱动技术,提出了一种新的服务连接架构,以实现服务间基于标准、松散耦合的通信方式,为基于服务的系统集成和扩展提供了更有效的支持。本文首先介绍了ESB的基本概念,然后从消息机制、...企业服务总线(Enterprise Service Bus,ESB)结合事件驱动技术,提出了一种新的服务连接架构,以实现服务间基于标准、松散耦合的通信方式,为基于服务的系统集成和扩展提供了更有效的支持。本文首先介绍了ESB的基本概念,然后从消息机制、消息转换、消息路由、服务容器四个方面分析了ESB核心功能组件,讨论和比较了当前主要的ESB软件产品和开源项目。ESB技术尚处在发展初期,本文分析了ESB研究目前存在的主要问题以及今后研究方向。展开更多
该文针对命名数据网络(Named Data Networking,NDN)应答内容的高效缓存和利用问题,依据内容请求分布的局域相似特征,提出一种协作缓存路由机制。缓存决策时,将垂直请求路径上的冗余消除和水平局域范围内的内容放置进行有效结合。垂直方...该文针对命名数据网络(Named Data Networking,NDN)应答内容的高效缓存和利用问题,依据内容请求分布的局域相似特征,提出一种协作缓存路由机制。缓存决策时,将垂直请求路径上的冗余消除和水平局域范围内的内容放置进行有效结合。垂直方向上,提出基于最大内容活跃因子的路径缓存策略,确定沿途转发对应的最大热点请求区域;水平方向上,采用一致性Hash协同缓存思想,实现应答内容的局域定向存储。路由查找时,将局域节点缓存引入到路由转发决策中,依据内容活跃等级动态执行局域缓存查找,增大内容请求就近响应概率。该机制减小了内容请求时延和缓存冗余,提高了缓存命中率,以少量额外的代价换取了内容请求开销的大幅下降,仿真结果验证了其有效性。展开更多
Content-based routing（CBR） publish/subscribe（P/S） system is an important class of distributed systems.This system differs from classical paradigms as messages are routed based on their content rather than their de...Content-based routing（CBR） publish/subscribe（P/S） system is an important class of distributed systems.This system differs from classical paradigms as messages are routed based on their content rather than their destination address,so as to provide a fine-granularity event dissemination,and support more flexibility decoupling applications.Covering-based routing is a typical optimization method of CBR and has been widely used as a building block in many distributed P/S systems,for it maintains a compact routing table and reduces the costs of communications and matching computations.So far as we know,this optimization method can only be implemented on acyclic overlay network,but cannot be directly utilized on cyclic networks.As the CBR in cyclic systems becomes a new focus of research,developing covering-based protocols and algorithms for cyclic P/S system is becoming significantly important.This paper contributes the cyclic covering-based routing protocol with corresponding algorithms to support covering-based protocol in cyclic P/S system,and implements it in PADRES,a distributed event management infrastructure based on the publish/subscribe model.展开更多
The?convergence of the Internet, sensor networks, and Radio Frequency Identification (RFID) systems has ushered to the concept of Internet of Things (IoT) which is capable of connecting daily things, making them smart...The?convergence of the Internet, sensor networks, and Radio Frequency Identification (RFID) systems has ushered to the concept of Internet of Things (IoT) which is capable of connecting daily things, making them smart through sensing, reasoning, and cooperating with other things. Further, RFID technology enables tracking of an object and assigning it a unique ID. IoT has the potential for a wide range of applications relating to healthcare, environment, transportation, cities… Moreover, the middleware is a basic component in the IoT architecture. It handles heterogeneity issues among IoT devices and provides a common framework for communication. More recently, the interest has focusing on developing publish/subscribe middleware systems for the IoT to allow asynchronous communication between the IoT devices. The scope of our paper is to study routing protocols for publish/subscribe schemes that include content and context-based routing. We propose an Energy-Efficient Content-Based Routing (EECBR) protocol for the IoT that minimizes the energy consumption. The proposed algorithm makes use of a virtual topology that is constructed in a centralized manner and then routes the events from the publishers to the intended interested subscribers in a distributed manner. EECBR has been simulated using Omnet++. The simulation results show that EECBR has a significant performance in term of the energy variance compared to the other schemes.展开更多
文摘企业服务总线(Enterprise Service Bus,ESB)结合事件驱动技术,提出了一种新的服务连接架构,以实现服务间基于标准、松散耦合的通信方式,为基于服务的系统集成和扩展提供了更有效的支持。本文首先介绍了ESB的基本概念,然后从消息机制、消息转换、消息路由、服务容器四个方面分析了ESB核心功能组件,讨论和比较了当前主要的ESB软件产品和开源项目。ESB技术尚处在发展初期,本文分析了ESB研究目前存在的主要问题以及今后研究方向。
文摘该文针对命名数据网络(Named Data Networking,NDN)应答内容的高效缓存和利用问题,依据内容请求分布的局域相似特征,提出一种协作缓存路由机制。缓存决策时,将垂直请求路径上的冗余消除和水平局域范围内的内容放置进行有效结合。垂直方向上,提出基于最大内容活跃因子的路径缓存策略,确定沿途转发对应的最大热点请求区域;水平方向上,采用一致性Hash协同缓存思想,实现应答内容的局域定向存储。路由查找时,将局域节点缓存引入到路由转发决策中,依据内容活跃等级动态执行局域缓存查找,增大内容请求就近响应概率。该机制减小了内容请求时延和缓存冗余,提高了缓存命中率,以少量额外的代价换取了内容请求开销的大幅下降,仿真结果验证了其有效性。
基金supported by the National Natural Science Foundation of China under Grant Nos.61070027,60752001the National Basic Research 973 Program of China under Grant No.2007CB310805+3 种基金the National High-Tech Research and Development 863 Program of China under Grant No.2006AA01A106the Beijing Science and Technology Plan Projects under Grant No.Z09000100960907the Beijing Natural Science Foundation under Grant No.4092043the Co-Building Program of Beijing Municipal Education Commission
文摘Content-based routing（CBR） publish/subscribe（P/S） system is an important class of distributed systems.This system differs from classical paradigms as messages are routed based on their content rather than their destination address,so as to provide a fine-granularity event dissemination,and support more flexibility decoupling applications.Covering-based routing is a typical optimization method of CBR and has been widely used as a building block in many distributed P/S systems,for it maintains a compact routing table and reduces the costs of communications and matching computations.So far as we know,this optimization method can only be implemented on acyclic overlay network,but cannot be directly utilized on cyclic networks.As the CBR in cyclic systems becomes a new focus of research,developing covering-based protocols and algorithms for cyclic P/S system is becoming significantly important.This paper contributes the cyclic covering-based routing protocol with corresponding algorithms to support covering-based protocol in cyclic P/S system,and implements it in PADRES,a distributed event management infrastructure based on the publish/subscribe model.
文摘The?convergence of the Internet, sensor networks, and Radio Frequency Identification (RFID) systems has ushered to the concept of Internet of Things (IoT) which is capable of connecting daily things, making them smart through sensing, reasoning, and cooperating with other things. Further, RFID technology enables tracking of an object and assigning it a unique ID. IoT has the potential for a wide range of applications relating to healthcare, environment, transportation, cities… Moreover, the middleware is a basic component in the IoT architecture. It handles heterogeneity issues among IoT devices and provides a common framework for communication. More recently, the interest has focusing on developing publish/subscribe middleware systems for the IoT to allow asynchronous communication between the IoT devices. The scope of our paper is to study routing protocols for publish/subscribe schemes that include content and context-based routing. We propose an Energy-Efficient Content-Based Routing (EECBR) protocol for the IoT that minimizes the energy consumption. The proposed algorithm makes use of a virtual topology that is constructed in a centralized manner and then routes the events from the publishers to the intended interested subscribers in a distributed manner. EECBR has been simulated using Omnet++. The simulation results show that EECBR has a significant performance in term of the energy variance compared to the other schemes.
