支持访问目的与信誉度标注的隐私保护方法

确保Web服务在满足用户功能性需求的前提下保护用户的隐私信息,是Web服务隐私保护的关键问题。针对传统的访问控制模型无法描述数据使用目的、请求者信誉度,以及策略定义必须指定数据使用者的问题,提出了以期望目的、期望信誉度标注为中心的隐私保护访问控制模型。首先分析了基于目的访问控制模型,对隐私信息集、使用目的以及之间的层次关系进行了形式化定义。其次给出了隐私信息集标注原则以及步骤,同时对XACML(extensible access control markup language)标准组件进行了扩展。然后给出了隐私策略执行系统中的目的信誉度分析器分析算法。最后通过实验验证了该模型的可行性和有效性,并与相关技术进行了比较分析。

支持目的与信誉度的隐私偏好规约模型

确保互联网服务在满足用户功能性需求的前提下保护隐私信息,是隐私保护研究的关键问题。访问控制是保护信息的传统手段,但其缺少使用目的、信誉度、义务等隐私语义,并且需要针对不同的数据使用者定义不同的策略。针对策略冗余、策略冲突等问题,提出了支持目的与信誉度绑定的隐私保护框架。首先给出了对应的访问控制模型,其次分析了隐私偏好的冲突问题,提出了目的冲突检测算法以及偏好冲突检测算法,最后通过实验证明了算法的可行性。

基于PBAC模型和IBE的医疗数据访问控制方案

医疗卫生领域形成的医疗大数据中包含了大量的个人隐私信息,面临着外部攻击和内部泄密的潜在安全隐患。传统的访问控制模型没有考虑用户访问目的在侧重数据隐私的访问控制中的重要作用,现有的对称、非对称加密技术又都存在密钥管理、证书管理复杂的问题。针对这些问题,提出了综合应用PBAC模型和IBE加密技术的访问控制方案,支持针对医疗数据密文的灵活访问控制。通过加入条件目的概念对PBAC模型进行扩展,实现了对目的树的全覆盖;以病患ID、条件访问位和预期目的作为IBE身份公钥进行病患数据加密,只有通过认证并且访问目的符合预期的用户才能获得相应的私钥和加密数据,从而实现对病患信息的访问。实验结果证明,该方案达到了细粒度访问控制和隐私保护的目的,并具有较好的性能。

具有功率分配因子的不可信中继系统的中断性能和遍历保密容量

基于不存在直接链路的具有不可信中继的三节点系统,本文在协作干扰模型中引入功率分配因子,对两种放大转发因子下系统的中断概率和遍历保密容量进行了计算及对比分析。首先,系统采用平均放大因子,推导出其保密中断概率;然后,在引入同样功率分配因子的基础上,系统改用自适应瞬时放大因子,得出保密中断概率的下界;为了对比,本文接着给出了系统两种情况下的遍历保密容量;最后,仿真验证了中断概率和遍历保密容量计算的准确性,数值仿真表明引入功率分配因子可减小系统的中断概率和提高系统的遍历保密容量,瞬时放大因子下系统性能较平均放大因子下更好。

Investigation on transformation process of trip mode choice for planned special events

This paper aims to provide a decision-making method for the transportation management strategies in guiding the transformation of trip mode choice during planned special events. The Expo 2010 Shanghai is taken as an example, and a structural equation model is employed to analyze the dynamic mechanism of trip mode choice behavior and the effectiveness of the transportation management measures at different stages. Based on the difference between the objective-oriented stated preference （SP） survey results and the objectives, together with the feedback from the previous stage survey, some adjustments on the transportation management measures are made in the next stage of the planning process until the objectives are eventually achieved. The results indicate that the adjustments on transportation management measures at different stages can effectively raise the transit share to 88.6%. Nonlocal visitors are inclined to choose nonstop modes of transportation and the companion attributes have the most significant effects on the trip mode choices of visitors. The research method is proved to be an effective way to support the decision making process of transportation management measures during planned special events in the future.

隐私数据访问控制机制在互联网医院诊疗服务中的应用

目的:建立以数据访问目的为驱动的隐私数据访问控制机制,使医生在互联网医院诊疗场景下只能读取满足当下诊疗所需的数据,而不是患者全部隐私信息。方法:建立一组基于访问目的的隐私数据访问属性,当用户的查询满足当下场景的访问规则时返回查询内容。结果:增加隐私数据属性和数量,不会对完成查询所需时间有影响。但当被查询的隐私数据表建有索引时,则能极大缩短完成查询的时间。结论:身份认证与数据访问目的机制相结合,能控制不同业务请求下对不同隐私数据的查询,是互联网诊疗行为监管和安全访问隐私数据的一种有效技术方法。增加隐私数据表对数据库存储压力影响不大,目前关系数据库的单表容量最大可达32 T。

A Simulation-Based Probabilistic Design Method for Arctic Sea Transport Systems

When designing an arctic cargo ship, it is necessary to consider multiple stochastic factors. This paper evaluates the merits of a simulation-based probabilistic design method specifically developed to deal with this challenge. The outcome of the paper indicates that the incorporation of simulations and probabilistic design parameters into the design process enables more informed design decisions. For instance, it enables the assessment of the stochastic transport capacity of an arctic ship, as well as of its long-term ice exposure that can be used to determine an appropriate level of ice-strengthening. The outcome of the paper also indicates that significant gains in transport system cost-efficiency can be obtained by extending the boundaries of the design task beyond the individual vessel. In the case of industrial shipping, this allows for instance the consideration of port-based cargo storage facilities allowing for temporary shortages in transport capacity and thus a reduction in the required fleet size / ship capacity.

基于UKF的雷达和机载ESM扩维跟踪

为有效提高异类传感器融合跟踪的效果,提出了一种基于UKF的雷达和机载ESM扩维跟踪算法。首先将目标和机载ESM的状态信息组合起来,形成一个高维的状态向量,从而有效抑制滤波中GPS定位误差所带来的影响;接着在此基础上采用UKF来实现目标的定位跟踪,以求进一步减小扩维后线性化误差加大等问题的影响。仿真结果表明,该算法可更好地实现对目标的定位跟踪。

Analogy-based software effort estimation using multi-objective feature selection

The feature selection in analogy-based software effort estimation （ASEE） is formulized as a multi-objective optimization problem. One objective is designed to maximize the effort estimation accuracy and the other objective is designed to minimize the number of selected features. Based on these two potential conflict objectives, a novel wrapper- based feature selection method, multi-objective feature selection for analogy-based software effort estimation （MASE）, is proposed. In the empirical studies, 77 projects in Desharnais and 62 projects in Maxwell from the real world are selected as the evaluation objects and the proposed method MASE is compared with some baseline methods. Final results show that the proposed method can achieve better performance by selecting fewer features when considering MMRE （mean magnitude of relative error）, MdMRE （median magnitude of relative error）, PRED （ 0. 25 ）, and SA （ standardized accuracy） performance metrics.