针对BYOD(bring your own device)、移动云计算等兼具强安全性、高开放性需求的新型应用场景,提出了一种移动嵌入式平台敏感应用防护方案.为满足强安全性需求,方案基于ARM TrustZone硬件隔离技术构建可信执行环境,即使在整个操作系统内...针对BYOD(bring your own device)、移动云计算等兼具强安全性、高开放性需求的新型应用场景,提出了一种移动嵌入式平台敏感应用防护方案.为满足强安全性需求,方案基于ARM TrustZone硬件隔离技术构建可信执行环境,即使在整个操作系统内核被攻破的情况下仍能保证敏感应用的安全.为满足高开放性需求,方案实现了传统TrustZone安全方案不具备的两大优势.首先,将TrustZone保护域扩展至普通世界,安全世界不再实现具体的敏感应用,而只实现一个轻量级监控模块用以监控普通世界内核的行为.因此整个系统可信计算基不随敏感应用数量的增加而增大,减少了其可攻击面和潜在漏洞。其次,监控模块确保内核为这些敏感应用提供安全的系统服务,从而为满足开放性需求提供关键功能支持,例如提供标准系统调用接口、敏感应用动态部署和加载等.最后,方案提出了内核主动证明机制,要求内核主动提供关键信息协助监控模块验证其自身行为,有效提高了系统运行效率.在真实设备上实现了原型系统,实验结果证明了该方案的安全性和较为理想的运行效率.展开更多
Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no ...Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no condition indicators designed for determining adequate timing for applying preventive maintenance and little literature relating to the development of pavement performance. This work presented the indicators, including crack ratio （Rc）, rutting depth （DR）, international roughness index （IIR） and sideway force coefficient （CsF） to determine the adequate timing for preventive maintenance in China. The proper ranges of each indicator to apply to preventive maintenance were then recommended. They are 0.28%-1.4% for Rc, 10-15 mm for DR, 1.97-3.5 for lrR, 40--50 for CSF. Based on pavement condition survey data collected on the test roads in Hebei Province, China, on the application of slurry seal at different timings, the pavement performance was established and the adequate timings for applying slurry seal was studied. Based on benefit-cost analysis, it is suggested that the fourth year is the optimal timing for applying slurry seal based on the condition in China. A framework is established to determine the adequate timings of applying other preventive maintenance methods.展开更多
文摘针对BYOD(bring your own device)、移动云计算等兼具强安全性、高开放性需求的新型应用场景,提出了一种移动嵌入式平台敏感应用防护方案.为满足强安全性需求,方案基于ARM TrustZone硬件隔离技术构建可信执行环境,即使在整个操作系统内核被攻破的情况下仍能保证敏感应用的安全.为满足高开放性需求,方案实现了传统TrustZone安全方案不具备的两大优势.首先,将TrustZone保护域扩展至普通世界,安全世界不再实现具体的敏感应用,而只实现一个轻量级监控模块用以监控普通世界内核的行为.因此整个系统可信计算基不随敏感应用数量的增加而增大,减少了其可攻击面和潜在漏洞。其次,监控模块确保内核为这些敏感应用提供安全的系统服务,从而为满足开放性需求提供关键功能支持,例如提供标准系统调用接口、敏感应用动态部署和加载等.最后,方案提出了内核主动证明机制,要求内核主动提供关键信息协助监控模块验证其自身行为,有效提高了系统运行效率.在真实设备上实现了原型系统,实验结果证明了该方案的安全性和较为理想的运行效率.
基金Project(IRT1050) supported by Program for Changjiang Scholars and Innovative Research Team in University, ChinaProject (2009318000027) supported by Ministry of Transport of ChinaProject(CHD2011TD002) supported by the Special Fund for Basic Scientific Research of Central Colleges, Chang’an University, China
文摘Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no condition indicators designed for determining adequate timing for applying preventive maintenance and little literature relating to the development of pavement performance. This work presented the indicators, including crack ratio （Rc）, rutting depth （DR）, international roughness index （IIR） and sideway force coefficient （CsF） to determine the adequate timing for preventive maintenance in China. The proper ranges of each indicator to apply to preventive maintenance were then recommended. They are 0.28%-1.4% for Rc, 10-15 mm for DR, 1.97-3.5 for lrR, 40--50 for CSF. Based on pavement condition survey data collected on the test roads in Hebei Province, China, on the application of slurry seal at different timings, the pavement performance was established and the adequate timings for applying slurry seal was studied. Based on benefit-cost analysis, it is suggested that the fourth year is the optimal timing for applying slurry seal based on the condition in China. A framework is established to determine the adequate timings of applying other preventive maintenance methods.
