Distributed Denial of Service （DDoS） attack is a major threat to the availability of Web service. The inherent presence of self-similarity in Web traffic motivates the applicability of time series analysis in the st...Distributed Denial of Service （DDoS） attack is a major threat to the availability of Web service. The inherent presence of self-similarity in Web traffic motivates the applicability of time series analysis in the study of the burst feature of DDoS attack. This paper presents a method of detecting DDoS attacks against Web server by analyzing the abrupt change of time series data obtained from Web traffic. Time series data are specified in reference sliding window and test sliding window, and the abrupt change is modeled using Auto-Regressive （AR） process. By comparing two adjacent nonoverlapping windows of the time series, the attack traffic could be detected at a time point. Combined with alarm correlation and location correlation, not only the presence of DDoS attack, but also its occurring time and location can be deter mined. The experimental results in a test environment are illustrated to justify our method.展开更多
To optimize the self-organization network, self-adaptation, real-time monitoring, remote management capability, and equipment reuse level of the meteorological station supporting the portable groundwater circulation w...To optimize the self-organization network, self-adaptation, real-time monitoring, remote management capability, and equipment reuse level of the meteorological station supporting the portable groundwater circulation wells, and to provide real-time and effective technical services and environmental data support for groundwater remediation, a real-time monitoring system design of the meteorological station supporting the portable groundwater circulation wells based on the existing equipment is proposed. A variety of environmental element information is collected and transmitted to the embedded web server by the intelligent weather transmitter, and then processed by the algorithm and stored internally, displayed locally, and published on the web. The system monitoring algorithm and user interface are designed in the CNWSCADA development environment to realize real-time processing and analysis of environmental data and monitoring, control, management, and maintenance of the system status. The PLC-controlled photovoltaic power generating panels and lithium battery packs are in line with the concept of energy saving and emission reduction, and at the same time, as an emergency power supply to guarantee the safety of equipment and data when the utility power fails to meet the requirements. The experiment proves that the system has the characteristics of remote control, real-time interaction, simple station deployment, reliable operation, convenient maintenance, and green environment protection, which is conducive to improving the comprehensive utilization efficiency of various types of environmental information and providing reliable data support, theoretical basis and guidance suggestions for the research of groundwater remediation technology and its disciplines, and the research and development of the movable groundwater cycling well monitoring system.展开更多
针对传统瓦斯多级监管系统存在的不足,研究了基于ArcGIS Server Java ADF和JSF框架下的网络地理信息关键技术,构建了ArcGIS server API和Java ADF两种技术集成的开发方案,设计了基于元数据的属性数据分布式存储和空间数据集中部署的数...针对传统瓦斯多级监管系统存在的不足,研究了基于ArcGIS Server Java ADF和JSF框架下的网络地理信息关键技术,构建了ArcGIS server API和Java ADF两种技术集成的开发方案,设计了基于元数据的属性数据分布式存储和空间数据集中部署的数据库存储方案,实现了B/S结构中的浏览器端与服务器端的瓦斯多级监管系统。展开更多
目的研究定时作业和多作业协调机制在SQL Server 2005数据库系统中的实现方法.方法采用定时作业和多作业协调机制来有效地优化系统资源,设计基于多定时作业协调方式的管理系统软件及硬件结构方案;使用了两种多作业协调的方法.结果以某...目的研究定时作业和多作业协调机制在SQL Server 2005数据库系统中的实现方法.方法采用定时作业和多作业协调机制来有效地优化系统资源,设计基于多定时作业协调方式的管理系统软件及硬件结构方案;使用了两种多作业协调的方法.结果以某大型矿山B/S企业综合系统为例,建立了以多作业协调机制为核心的后台数据库动态管理系统,通过在定时作业中调用存储过程对系统数据库中的数据进行整理、备份、更新和汇总运算,并运用多作业协调机制实现多个定时作业的高效执行.结论工程应用证明在大型数据库系统中,多作业协调机制可以有效地解决数据冗余问题,提高了系统响应速率.展开更多
边缘计算作为实现5G通讯标准的关键技术,其通过将用户的终端任务卸载到附近具有计算与存储资源的边缘服务器上,达到提高服务质量的目的。论文针对边缘服务器的放置问题,提出了一种在5G网络中最小化用户时延的边缘服务器放置方法ESPFA(Ed...边缘计算作为实现5G通讯标准的关键技术,其通过将用户的终端任务卸载到附近具有计算与存储资源的边缘服务器上,达到提高服务质量的目的。论文针对边缘服务器的放置问题,提出了一种在5G网络中最小化用户时延的边缘服务器放置方法ESPFA(Edge Server Placement based on Firefly Algorithm),将用户平均时延、边缘服务器负载均衡量和边缘服务器平均资源利用率进行加权、并作为指标衡量系统整体性能。仿真结果表明,与主流的放置方法相比,在放置边缘服务器数量为10时,论文提出的萤火虫算法降低时延效果明显,比传统K-Means算法下降了16.2%,并且算法系统性能优良,分别比Random算法和Top-K算法提升了9.4%和22.6%。展开更多
基金Supported by the National Natural Science Funda-tion of China (60373075)
文摘Distributed Denial of Service （DDoS） attack is a major threat to the availability of Web service. The inherent presence of self-similarity in Web traffic motivates the applicability of time series analysis in the study of the burst feature of DDoS attack. This paper presents a method of detecting DDoS attacks against Web server by analyzing the abrupt change of time series data obtained from Web traffic. Time series data are specified in reference sliding window and test sliding window, and the abrupt change is modeled using Auto-Regressive （AR） process. By comparing two adjacent nonoverlapping windows of the time series, the attack traffic could be detected at a time point. Combined with alarm correlation and location correlation, not only the presence of DDoS attack, but also its occurring time and location can be deter mined. The experimental results in a test environment are illustrated to justify our method.
文摘To optimize the self-organization network, self-adaptation, real-time monitoring, remote management capability, and equipment reuse level of the meteorological station supporting the portable groundwater circulation wells, and to provide real-time and effective technical services and environmental data support for groundwater remediation, a real-time monitoring system design of the meteorological station supporting the portable groundwater circulation wells based on the existing equipment is proposed. A variety of environmental element information is collected and transmitted to the embedded web server by the intelligent weather transmitter, and then processed by the algorithm and stored internally, displayed locally, and published on the web. The system monitoring algorithm and user interface are designed in the CNWSCADA development environment to realize real-time processing and analysis of environmental data and monitoring, control, management, and maintenance of the system status. The PLC-controlled photovoltaic power generating panels and lithium battery packs are in line with the concept of energy saving and emission reduction, and at the same time, as an emergency power supply to guarantee the safety of equipment and data when the utility power fails to meet the requirements. The experiment proves that the system has the characteristics of remote control, real-time interaction, simple station deployment, reliable operation, convenient maintenance, and green environment protection, which is conducive to improving the comprehensive utilization efficiency of various types of environmental information and providing reliable data support, theoretical basis and guidance suggestions for the research of groundwater remediation technology and its disciplines, and the research and development of the movable groundwater cycling well monitoring system.
文摘针对传统瓦斯多级监管系统存在的不足,研究了基于ArcGIS Server Java ADF和JSF框架下的网络地理信息关键技术,构建了ArcGIS server API和Java ADF两种技术集成的开发方案,设计了基于元数据的属性数据分布式存储和空间数据集中部署的数据库存储方案,实现了B/S结构中的浏览器端与服务器端的瓦斯多级监管系统。
文摘目的研究定时作业和多作业协调机制在SQL Server 2005数据库系统中的实现方法.方法采用定时作业和多作业协调机制来有效地优化系统资源,设计基于多定时作业协调方式的管理系统软件及硬件结构方案;使用了两种多作业协调的方法.结果以某大型矿山B/S企业综合系统为例,建立了以多作业协调机制为核心的后台数据库动态管理系统,通过在定时作业中调用存储过程对系统数据库中的数据进行整理、备份、更新和汇总运算,并运用多作业协调机制实现多个定时作业的高效执行.结论工程应用证明在大型数据库系统中,多作业协调机制可以有效地解决数据冗余问题,提高了系统响应速率.
文摘边缘计算作为实现5G通讯标准的关键技术,其通过将用户的终端任务卸载到附近具有计算与存储资源的边缘服务器上,达到提高服务质量的目的。论文针对边缘服务器的放置问题,提出了一种在5G网络中最小化用户时延的边缘服务器放置方法ESPFA(Edge Server Placement based on Firefly Algorithm),将用户平均时延、边缘服务器负载均衡量和边缘服务器平均资源利用率进行加权、并作为指标衡量系统整体性能。仿真结果表明,与主流的放置方法相比,在放置边缘服务器数量为10时,论文提出的萤火虫算法降低时延效果明显,比传统K-Means算法下降了16.2%,并且算法系统性能优良,分别比Random算法和Top-K算法提升了9.4%和22.6%。
