This paper proposes a security policy model for mandatory access control in class B1 database management system whose level of labeling is tuple. The relation hierarchical data model is extended to multilevel relatio...This paper proposes a security policy model for mandatory access control in class B1 database management system whose level of labeling is tuple. The relation hierarchical data model is extended to multilevel relation hierarchical data model. Based on the multilevel relation hierarchical data model, the concept of upper lower layer relational integrity is presented after we analyze and eliminate the covert channels caused by the database integrity. Two SQL statements are extended to process polyinstantiation in the multilevel secure environment. The system is based on the multilevel relation hierarchical data model and is capable of integratively storing and manipulating multilevel complicated objects ( e.g., multilevel spatial data) and multilevel conventional data ( e.g., integer, real number and character string).展开更多
为满足训练的信息化需求,设计了灵活通用的数据协议和虚实结合的信息引接系统。基于中间件的分层设计思路,实现了外部信息接收、对内信息转发、通信协议解析与转换、信息对接联调、数据文件记录、配置管理以及信息流量统计等功能;采用了...为满足训练的信息化需求,设计了灵活通用的数据协议和虚实结合的信息引接系统。基于中间件的分层设计思路,实现了外部信息接收、对内信息转发、通信协议解析与转换、信息对接联调、数据文件记录、配置管理以及信息流量统计等功能;采用了MVC软件架构模式,选用Visual Studio 2015作为开发工具,以Oracle数据库作为底层支撑,构建了实装信息及虚拟目标信息接收模块、建立数据映射关系模块、读取数据库方案模块、基础通信接收内部航迹模块、数据包发送模块。实际应用效果表明,该系统能够屏蔽外部装备系统、仿真系统和网络协议之间的差异,提供互联互通,适应虚实结合的训练任务,提高保障能力。该系统具有良好的适应性和可扩展性,可以满足信息化条件下系统的应用和发展需要。展开更多
分析和研究了网格环境中数据访问和集成(data access and integration,DAI)需求,结合中间件技术的特点,提出了具有N层应用体系结构的DAI中间件实现策略,即在不同种类的数据资源和网格应用之间构建了一个中间层软件——“虚拟数据库系统...分析和研究了网格环境中数据访问和集成(data access and integration,DAI)需求,结合中间件技术的特点,提出了具有N层应用体系结构的DAI中间件实现策略,即在不同种类的数据资源和网格应用之间构建了一个中间层软件——“虚拟数据库系统”,经授权认证的合法用户可通过“虚拟数据库系统”提供的标准访问接口及统一数据格式对网格环境中各种分布的、异构的、不同种类的数据资源进行动态访问和集成。展开更多
采用开放式网格服务体系结构-数据访问与集成(OGSA-DAI)中间件的数据访问模式,利用空间数据引擎的空间数据管理能力,构建分布式的多源网格数据服务(GDS).基于WKT(Well Known Text)中间数据模型,构建一个空间数据查询和访问的统一模式,...采用开放式网格服务体系结构-数据访问与集成(OGSA-DAI)中间件的数据访问模式,利用空间数据引擎的空间数据管理能力,构建分布式的多源网格数据服务(GDS).基于WKT(Well Known Text)中间数据模型,构建一个空间数据查询和访问的统一模式,并将结果集转换为通用的空间数据格式.实例表明,通过WKT中间数据模型,可实现自定义查询或跨数据服务资源的联合查询,查询结果可以方便地转换为XML,SVG,GML文档.展开更多
Double data rate synchronous dynamic random access memory （DDR3） has become one of the most mainstream applications in current server and computer systems. In order to quickly set up a system-level signal integrity ...Double data rate synchronous dynamic random access memory （DDR3） has become one of the most mainstream applications in current server and computer systems. In order to quickly set up a system-level signal integrity （SI） simulation flow for the DDR3 interface, two system-level SI simulation methodologies, which are board-level S-parameter extraction in the frequency-domain and system-level simulation assumptions in the time domain, are introduced in this paper. By comparing the flow of Speed2000 and PowerSI/Hspice, PowerSI is chosen for the printed circuit board （PCB） board-level S-parameter extraction, while Tektronix oscilloscope （TDS7404） is used for the DDR3 waveform measurement. The lab measurement shows good agreement between simulation and measurement. The study shows that the combination of PowerSI and Hspice is recommended for quick system-level DDR3 SI simulation.展开更多
With the popularity of the Internet and improvement of information technology,digital information sharing increasingly becomes the trend.More and More universities pay attention to the digital campus,and the construct...With the popularity of the Internet and improvement of information technology,digital information sharing increasingly becomes the trend.More and More universities pay attention to the digital campus,and the construction of digital library has become the focus of digital campus.A set of manageable,authenticated and secure solutions are needed for remote access to make the campus network be a transit point for the outside users.Remote Access IPSEC Virtual Private Network gives the solution of remote access to e-library resources,networks resources and so on very safely through a public network.It establishes a safe and stable tunnel which encrypts the data passing through it with robust secured algorithms.It is to establish a virtual private network in Internet,so that the two long-distance network users can transmit data to each other in a dedicated network channel.Using this technology,multi-network campus can communicate securely in the unreliable public internet.展开更多
A multilevel secure relation hierarchical data model for multilevel secure database is extended from the relation hierarchical data model in single level environment in this paper. Based on the model, an upper lowe...A multilevel secure relation hierarchical data model for multilevel secure database is extended from the relation hierarchical data model in single level environment in this paper. Based on the model, an upper lower layer relationalintegrity is presented after we analyze and eliminate the covert channels caused by the database integrity.Two SQL statements are extended to process polyinstantiation in the multilevel secure environment.The system based on the multilevel secure relation hierarchical data model is capable of integratively storing and manipulating complicated objects ( e.g. , multilevel spatial data) and conventional data ( e.g. , integer, real number and character string) in multilevel secure database.展开更多
随着云计算在学术界和工业界的兴起,云计算也不可避免的带来了一些安全问题.本文对云计算的安全需求进行了总结,指出云计算不仅在机密性、数据完整性、访问控制和身份认证等传统安全性上存在需求,而且在可信性、配置安全性、虚拟机安全...随着云计算在学术界和工业界的兴起,云计算也不可避免的带来了一些安全问题.本文对云计算的安全需求进行了总结,指出云计算不仅在机密性、数据完整性、访问控制和身份认证等传统安全性上存在需求,而且在可信性、配置安全性、虚拟机安全性等方面具有新的安全需求.我们对云计算的两个典型产品Amazon Web Services和Windows Azure的安全状况进行了总结,并阐述了针对云计算的拒绝服务攻击和旁通道攻击.基于云计算的安全需求和面临的攻击,对现有安全机制进行了优缺点分析,系统的总结了现有的安全机制.展开更多
文摘This paper proposes a security policy model for mandatory access control in class B1 database management system whose level of labeling is tuple. The relation hierarchical data model is extended to multilevel relation hierarchical data model. Based on the multilevel relation hierarchical data model, the concept of upper lower layer relational integrity is presented after we analyze and eliminate the covert channels caused by the database integrity. Two SQL statements are extended to process polyinstantiation in the multilevel secure environment. The system is based on the multilevel relation hierarchical data model and is capable of integratively storing and manipulating multilevel complicated objects ( e.g., multilevel spatial data) and multilevel conventional data ( e.g., integer, real number and character string).
文摘为满足训练的信息化需求,设计了灵活通用的数据协议和虚实结合的信息引接系统。基于中间件的分层设计思路,实现了外部信息接收、对内信息转发、通信协议解析与转换、信息对接联调、数据文件记录、配置管理以及信息流量统计等功能;采用了MVC软件架构模式,选用Visual Studio 2015作为开发工具,以Oracle数据库作为底层支撑,构建了实装信息及虚拟目标信息接收模块、建立数据映射关系模块、读取数据库方案模块、基础通信接收内部航迹模块、数据包发送模块。实际应用效果表明,该系统能够屏蔽外部装备系统、仿真系统和网络协议之间的差异,提供互联互通,适应虚实结合的训练任务,提高保障能力。该系统具有良好的适应性和可扩展性,可以满足信息化条件下系统的应用和发展需要。
文摘分析和研究了网格环境中数据访问和集成(data access and integration,DAI)需求,结合中间件技术的特点,提出了具有N层应用体系结构的DAI中间件实现策略,即在不同种类的数据资源和网格应用之间构建了一个中间层软件——“虚拟数据库系统”,经授权认证的合法用户可通过“虚拟数据库系统”提供的标准访问接口及统一数据格式对网格环境中各种分布的、异构的、不同种类的数据资源进行动态访问和集成。
文摘采用开放式网格服务体系结构-数据访问与集成(OGSA-DAI)中间件的数据访问模式,利用空间数据引擎的空间数据管理能力,构建分布式的多源网格数据服务(GDS).基于WKT(Well Known Text)中间数据模型,构建一个空间数据查询和访问的统一模式,并将结果集转换为通用的空间数据格式.实例表明,通过WKT中间数据模型,可实现自定义查询或跨数据服务资源的联合查询,查询结果可以方便地转换为XML,SVG,GML文档.
基金supported by the National Natural Science Foundation of China under Grant No.61161001
文摘Double data rate synchronous dynamic random access memory （DDR3） has become one of the most mainstream applications in current server and computer systems. In order to quickly set up a system-level signal integrity （SI） simulation flow for the DDR3 interface, two system-level SI simulation methodologies, which are board-level S-parameter extraction in the frequency-domain and system-level simulation assumptions in the time domain, are introduced in this paper. By comparing the flow of Speed2000 and PowerSI/Hspice, PowerSI is chosen for the printed circuit board （PCB） board-level S-parameter extraction, while Tektronix oscilloscope （TDS7404） is used for the DDR3 waveform measurement. The lab measurement shows good agreement between simulation and measurement. The study shows that the combination of PowerSI and Hspice is recommended for quick system-level DDR3 SI simulation.
文摘With the popularity of the Internet and improvement of information technology,digital information sharing increasingly becomes the trend.More and More universities pay attention to the digital campus,and the construction of digital library has become the focus of digital campus.A set of manageable,authenticated and secure solutions are needed for remote access to make the campus network be a transit point for the outside users.Remote Access IPSEC Virtual Private Network gives the solution of remote access to e-library resources,networks resources and so on very safely through a public network.It establishes a safe and stable tunnel which encrypts the data passing through it with robust secured algorithms.It is to establish a virtual private network in Internet,so that the two long-distance network users can transmit data to each other in a dedicated network channel.Using this technology,multi-network campus can communicate securely in the unreliable public internet.
文摘A multilevel secure relation hierarchical data model for multilevel secure database is extended from the relation hierarchical data model in single level environment in this paper. Based on the model, an upper lower layer relationalintegrity is presented after we analyze and eliminate the covert channels caused by the database integrity.Two SQL statements are extended to process polyinstantiation in the multilevel secure environment.The system based on the multilevel secure relation hierarchical data model is capable of integratively storing and manipulating complicated objects ( e.g. , multilevel spatial data) and conventional data ( e.g. , integer, real number and character string) in multilevel secure database.
文摘随着云计算在学术界和工业界的兴起,云计算也不可避免的带来了一些安全问题.本文对云计算的安全需求进行了总结,指出云计算不仅在机密性、数据完整性、访问控制和身份认证等传统安全性上存在需求,而且在可信性、配置安全性、虚拟机安全性等方面具有新的安全需求.我们对云计算的两个典型产品Amazon Web Services和Windows Azure的安全状况进行了总结,并阐述了针对云计算的拒绝服务攻击和旁通道攻击.基于云计算的安全需求和面临的攻击,对现有安全机制进行了优缺点分析,系统的总结了现有的安全机制.
