共查询到18条相似文献,搜索用时 93 毫秒
1.
2.
构建大规模分布式基于内容的发布订阅系统仍然面临挑战。大多数现存的系统使用简单、事先定义的、静态的覆盖网络拓扑结构,这导致其具有较差的伸缩性和容错性。提出了一个构建于P2P网络之上的基于内容的发布/订阅系统,借助Pastry网络实现了基于内容的路由协议,其路由算法通过集中点机制避免了全局网络广播并且具有自组织和容错的特性,能够处理任意节点或者链路的失效。仿真结果表明该系统具有较好的路由效率和伸缩性,事件代理所需维护的路由表也更小。 相似文献
3.
4.
文章提出了一种兴趣粒度相关的订阅技术,订阅者可以描述在不同的上下文中对事件的感兴趣粒度。 相似文献
5.
6.
在RFID信息服务网络中,设计了一种支持复合订阅的可靠的路由算法:在订阅转发阶段,我们将每一个复合订阅按照其语法结构进行分解,并将每个复合订阅成份分配给多个RFID信息服务(构成一个复合订阅存储单元)去维护,而事件则按照订阅分解的反方向和匹配的结果进行转发与合并.由于每个复合订阅存在多个副本,因而会显著减少因某个副本失效而产生的事件丢失.本文也给出了复合订阅存储单元内部多个复合订阅副本一致性的保持方法,以及核心信息服务的选举方法.实验结果表明,该路由算法有较高的容错性,性能可以满足实际应用的需要. 相似文献
7.
8.
9.
10.
事件句的句法结构有助于语义理解。针对中文领域的事件检测任务,本文设计了面向句义及句法的事件检测模型(BDD)以增强对事件句的理解能力。以基于来自变压器的双向编码器表示(BERT)的动态词向量为信息源,设计基于依存树的长短时记忆网络模型(D-T-LSTM)以融合学习句法结构及上下文语义,并加入基于依存向量的注意力机制强化对不同句法结构的区分度,在中文突发事件语料库(CEC)上的实验证明了本文模型的有效性,精确率、召回率、F1值均靠前,且F1值比基准模型提升了5.4%,召回率提升了0.4%。 相似文献
11.
A publish/subscribe system dynamically routes and delivers events from sources to interested users, and is an extremely useful communication service when it is not clear in advance who needs what information. In this paper we discuss how a publish/subscribe system can be extended to operate in a mobile environment, where events can be generated by moving sensors or users, and subscribers can request delivery at handheld and/or mobile devices. We describe how the publish/subscribe system itself can be distributed across multiple (possibly mobile) computers to distribute load, and how the system can be replicated to cope with failures, message loss, and disconnections. 相似文献
12.
13.
14.
根据现阶段靶场指挥显示信息分发系统的需求,针对指挥显示系统面临异构信息接入困难的问题,提出了基于发布/订阅机制的指挥显示信息分发系统的基本架构和工作流程,并对其关键技术进行探讨,可为靶场指挥显示系统的建设提供参考。 相似文献
15.
Publish/subscribe paradigm is often adopted to create the communication infrastructure of the Internet of Things(IoT)for many clients to access enormous real-time sensor data.However,most current publish/subscribe middlewares are based on traditional ossified IP networks,which are difficult to enable Quality of Service(QoS).How to design the next generation publish/subscribe middleware has become an urgent problem.The emerging Software Defined Networking(SDN)provides new opportunities to improve the QoS of publish/subscribe facilities for delivering events in IoT owing to its customized programmability and centralized control.We can encode event topics,priorities and security policies into flow entries of SDN-enabled switches to satisfy personalized QoS needs.In this paper,we propose a cross-layer QoS enabled SDN-like publish/subscribe communication infrastructure,aiming at building an IoT platform to seamlessly connect IoT services with SDN networks and improving the QoS of delivering events.We first present an SDN-like topic-oriented publish/subscribe middleware architecture with a cross-layer QoS control framework.Then we discuss prototype implementation,including topic management,topology maintenance,event routing and policy management.In the end,we use differentiated services and cross-layer access control as cross-layer QoS scenarios to verify the prototype.Experimental results show that our middleware is effective. 相似文献
16.
CAKA: a novel cache‐aware K‐anycast routing scheme for publish/subscribe‐based information‐centric network 下载免费PDF全文
Jing Ren Kejie Lu Fei Tang Jin Wang Jianping Wang Sheng Wang Shucheng Liu 《International Journal of Communication Systems》2015,28(17):2167-2179
In the past few years, many publish/subscribe‐based information‐centric network (PS‐ICN) architectures have been proposed and investigated to efficiently deliver information from content publishers to subscribers. However, most existing studies on PS‐ICN have not considered how to utilize in‐network caches, which is a common but important feature in ICN. To address this issue, in this paper, we propose a novel cache‐aware K‐anycast routing scheme, namely, CAKA, that can significantly improve the performance of content delivery. Specifically, we choose PURSUIT, which is one of the most important PS‐ICN architectures, and leverage its bidirectional communication procedure to do the following: (1) enable multiple publishers to send probing messages to the same subscriber; and (2) allow the subscriber to retrieve content objects using K‐anycast routing and network coding. In this study, we extend the PURSUIT protocol to support cache‐aware K‐anycast routing and design the algorithms to choose multiple partially disjointed paths for probing, and to select paths for content retrieval. To evaluate the performance of the proposed scheme, we develop not only a simulation testbed, but also a prototype running in a realistic network environment. Our studies show that the proposed scheme can significantly reduce the average hops to retrieve content objects, with very small overheads. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
17.
改进蚁群算法在QoS路由中的应用与研究 总被引:1,自引:0,他引:1
在分析传统蚁群算法缺陷及其在QoS路由中的应用的基础上,提出了一种与真实蚁群系统更加相符的基于双向寻路和信息素扩散的蚁群算法,采用来自源节点和目的节点两个方向的蚂蚁探路的同时进行信息扩散.仿真结果表明,该改进蚁群算法在网络规模较大的条件下仍能快速找到满足QoS路由性能指标的路由,节省了QoS路由搜索时间,提高了网络服务能力. 相似文献