文章分析了"互动式"教学大纲研究现状,阐述了MOOC(Massive Open Online Courses)平台的教学模式特性.以《果蔬保藏学》为例,从教学大纲的编制、"发布/订阅"、动态调整三个方面,研究MOOC平台下"Pub/Sub(Publish...文章分析了"互动式"教学大纲研究现状,阐述了MOOC(Massive Open Online Courses)平台的教学模式特性.以《果蔬保藏学》为例,从教学大纲的编制、"发布/订阅"、动态调整三个方面,研究MOOC平台下"Pub/Sub(Publish/Subscribe)互动式"教学大纲的设计与实施.展开更多
针对核电等工业现场设备对OPC UA Pub/Sub技术的需求,对OPC UA Pub/Sub规范进行了研究,分析OPC UA Pub/Sub模式的技术特点和应用场景,开发实现了符合规范的基于OPC UA服务器的Pub/Sub通讯模式。该通讯模式使用OPC UA Client/Server连接...针对核电等工业现场设备对OPC UA Pub/Sub技术的需求,对OPC UA Pub/Sub规范进行了研究,分析OPC UA Pub/Sub模式的技术特点和应用场景,开发实现了符合规范的基于OPC UA服务器的Pub/Sub通讯模式。该通讯模式使用OPC UA Client/Server连接模式进行OPC UA Pub/Sub的配置,使用OPC UA Pub/Sub模式进行数据传输。与标准实现的应用进行通讯测试表明,该服务器具备OPC UA Pub/Sub数据传输能力。展开更多
Publish/subscribe(pub/sub)systems are widely used in large-scale messaging systems due to their asynchronous and decoupled nature.With the population of pub/sub cloud services,the privacy protection problem of pub/sub...Publish/subscribe(pub/sub)systems are widely used in large-scale messaging systems due to their asynchronous and decoupled nature.With the population of pub/sub cloud services,the privacy protection problem of pub/sub systems has started to emerge,and events and subscriptions are exposed when executing event matching on untrustworthy cloud brokers.However,as the number of subscriptions increases,the effectiveness of the previous confidentiality protection approaches declines drastically.In this paper,we propose SBM(scalable blind matching),an effective confidentiality protection scheme for pub/sub systems.To the best of our knowledge,SBM is the first scheme that applies order-preserving encryption algorithm to protect the system’s confidentiality and ensure its scalability.In this scheme,SBM-I is highly effective in subscription matching but is unable to achieve ideal security IND-OCPA,whereas SBM-II is suggested to ensure system security and SGX is used to reduce interaction and boost ciphertext matching performance.The experiment demonstrates that this method has better matching performance compared to others:the average matching time of SBM-I is 3–4 orders of magnitude faster than the matching algorithm MP and SGX-based algorithm SCBR when the number of subscriptions is 500,000,and the average matching time of SBM-II is 40 times faster than MP and 24 times than SCBR.展开更多
来自不同传感器网络的流数据共享和集成对于带动相关业务和行业的创新具有重要意义.现有的传感网络往往是任务导向或领域专用的,仅适用于特定的应用场景,难以有效地在不同应用间共享和重用其数据资源.传感流数据的服务化是一种有效解决...来自不同传感器网络的流数据共享和集成对于带动相关业务和行业的创新具有重要意义.现有的传感网络往往是任务导向或领域专用的,仅适用于特定的应用场景,难以有效地在不同应用间共享和重用其数据资源.传感流数据的服务化是一种有效解决物理传感网络数据资源共享和重用的方法.针对已有服务化方法在应对大规模传感流数据共享和用户并发访问方面存在的局限性,该文提出了一种面向传感流数据的服务化封装方法——SDaaS(Stream Data as a Service),该方法使用事件的方式驱动传感流数据的处理和传输,通过对传感数据的融合操作实现服务对传感流数据的深层次加工,并基于Pub/Sub机制实现传感流数据的按需分发.文中基于Spark Streaming实现对大规模流数据加工操作的封装,并通过对传统的基于匹配树的事件匹配算法进行改进实现了高效的流数据内容分发,以保障将传感数据实时的分发给相应需求.该文通过实验验证了流数据服务的性能,印证了流数据服务能够响应不同的数据需求,在毫秒级别将数据流分发给不同应用.展开更多
文摘文章分析了"互动式"教学大纲研究现状,阐述了MOOC(Massive Open Online Courses)平台的教学模式特性.以《果蔬保藏学》为例,从教学大纲的编制、"发布/订阅"、动态调整三个方面,研究MOOC平台下"Pub/Sub(Publish/Subscribe)互动式"教学大纲的设计与实施.
文摘针对核电等工业现场设备对OPC UA Pub/Sub技术的需求,对OPC UA Pub/Sub规范进行了研究,分析OPC UA Pub/Sub模式的技术特点和应用场景,开发实现了符合规范的基于OPC UA服务器的Pub/Sub通讯模式。该通讯模式使用OPC UA Client/Server连接模式进行OPC UA Pub/Sub的配置,使用OPC UA Pub/Sub模式进行数据传输。与标准实现的应用进行通讯测试表明,该服务器具备OPC UA Pub/Sub数据传输能力。
基金This work was supported by the Natural Science Foundation of Beijing Municipality(M21037)Key Technologies Research and Development Program(2022YFF0902701)2022 Industrial Internet Public Service Platform-Industrial Internet Oriented Virtual Currency Mining Governance Public Service Platform Project by the Ministry of Industry and Information Technology of PRC,Major Research and Application Project for the Supervision Platform of Virtual Currency Mining Behavior by the Ministry of Education of PRC,and the 111 Project(Grant No.B21049).
文摘Publish/subscribe(pub/sub)systems are widely used in large-scale messaging systems due to their asynchronous and decoupled nature.With the population of pub/sub cloud services,the privacy protection problem of pub/sub systems has started to emerge,and events and subscriptions are exposed when executing event matching on untrustworthy cloud brokers.However,as the number of subscriptions increases,the effectiveness of the previous confidentiality protection approaches declines drastically.In this paper,we propose SBM(scalable blind matching),an effective confidentiality protection scheme for pub/sub systems.To the best of our knowledge,SBM is the first scheme that applies order-preserving encryption algorithm to protect the system’s confidentiality and ensure its scalability.In this scheme,SBM-I is highly effective in subscription matching but is unable to achieve ideal security IND-OCPA,whereas SBM-II is suggested to ensure system security and SGX is used to reduce interaction and boost ciphertext matching performance.The experiment demonstrates that this method has better matching performance compared to others:the average matching time of SBM-I is 3–4 orders of magnitude faster than the matching algorithm MP and SGX-based algorithm SCBR when the number of subscriptions is 500,000,and the average matching time of SBM-II is 40 times faster than MP and 24 times than SCBR.
文摘来自不同传感器网络的流数据共享和集成对于带动相关业务和行业的创新具有重要意义.现有的传感网络往往是任务导向或领域专用的,仅适用于特定的应用场景,难以有效地在不同应用间共享和重用其数据资源.传感流数据的服务化是一种有效解决物理传感网络数据资源共享和重用的方法.针对已有服务化方法在应对大规模传感流数据共享和用户并发访问方面存在的局限性,该文提出了一种面向传感流数据的服务化封装方法——SDaaS(Stream Data as a Service),该方法使用事件的方式驱动传感流数据的处理和传输,通过对传感数据的融合操作实现服务对传感流数据的深层次加工,并基于Pub/Sub机制实现传感流数据的按需分发.文中基于Spark Streaming实现对大规模流数据加工操作的封装,并通过对传统的基于匹配树的事件匹配算法进行改进实现了高效的流数据内容分发,以保障将传感数据实时的分发给相应需求.该文通过实验验证了流数据服务的性能,印证了流数据服务能够响应不同的数据需求,在毫秒级别将数据流分发给不同应用.
