当前,已有的可授权电子现金系统通信效率不高,同时其公平交换子协议要求使用低效的cutand-choose证明技术且集中式的可信第三方(trusted third party,TTP)容易遭受拒绝服务攻击.此外,多个相关的公平支付系统或者要求使用cut-and-choose...当前,已有的可授权电子现金系统通信效率不高,同时其公平交换子协议要求使用低效的cutand-choose证明技术且集中式的可信第三方(trusted third party,TTP)容易遭受拒绝服务攻击.此外,多个相关的公平支付系统或者要求使用cut-and-choose证明技术,或者使用了具有安全性缺陷的可验证加密技术.利用基于属性的自盲化证书系统构造了一个具有属性的直接匿名证明(direct anonymous attestation with attributes,DAA-A)方案,然后基于该方案构造了满足更强可开脱性的可授权电子现金系统.为了提高用户端在支付过程中的运算效率,使用了Arfaoui等人的集合关系证明协议,同时利用预计算技术对用户的知识签名进行了效率优化.为了避免执行低效的cut-and-choose证明,设计了一个支持分布式TTP的乐观公平交换子协议.通过与Golle-Mironov模型相结合,新系统可以应用于外包计算领域.与已有同类系统相比,新系统同时满足允许多次支付、无需使用cut-and-choose技术和用户无状态性等多个理想性质.此外,新系统的公平交换子协议引入了分布式TTP,即考虑了拒绝服务攻击的风险.展开更多
Objective:Entrustable professional activities(EPAs)is a newly emerging concept.This paper aims at analyzing the concept of"EPAs"to clarify the meaning and to identify its components for optimum understanding...Objective:Entrustable professional activities(EPAs)is a newly emerging concept.This paper aims at analyzing the concept of"EPAs"to clarify the meaning and to identify its components for optimum understanding of the concept for use in nursing education and future research.Method:Three databases-ProQuest,Ovid,and PubMed-were retrieved,and Walker and Avant's concept analysis approach was used to analyze the concept of EPAs.Results:Based on the analysis,three attributes of EPAs were defined,namely (1)EPAs should be restricted to a limited number of tasks;(2)reflect the experience curve;and (3)include acceptance of responsibility and accountability.The antecedent of EPAs is a holistic and integrated assessment approach.This will eventually lead to anticipated consequences such as a mastery of core competencies and an increase in the level of autonomy.Conclusion:The study may contribute to a reduction in the ambiguity of this concept to better apply it in nursing practice.展开更多
After analysis of the existing problems of traditional RBAC model, user group and resource domain are introduced to conduct finely granular extension of RBAC model. Extended model reduces the redundancy of roles, lowe...After analysis of the existing problems of traditional RBAC model, user group and resource domain are introduced to conduct finely granular extension of RBAC model. Extended model reduces the redundancy of roles, lowers the complexity of authorization management and enhances the flexibility and maintainability of users＇ authorization. It is well proved in its application in postgraduate student management system.展开更多
文摘当前,已有的可授权电子现金系统通信效率不高,同时其公平交换子协议要求使用低效的cutand-choose证明技术且集中式的可信第三方(trusted third party,TTP)容易遭受拒绝服务攻击.此外,多个相关的公平支付系统或者要求使用cut-and-choose证明技术,或者使用了具有安全性缺陷的可验证加密技术.利用基于属性的自盲化证书系统构造了一个具有属性的直接匿名证明(direct anonymous attestation with attributes,DAA-A)方案,然后基于该方案构造了满足更强可开脱性的可授权电子现金系统.为了提高用户端在支付过程中的运算效率,使用了Arfaoui等人的集合关系证明协议,同时利用预计算技术对用户的知识签名进行了效率优化.为了避免执行低效的cut-and-choose证明,设计了一个支持分布式TTP的乐观公平交换子协议.通过与Golle-Mironov模型相结合,新系统可以应用于外包计算领域.与已有同类系统相比,新系统同时满足允许多次支付、无需使用cut-and-choose技术和用户无状态性等多个理想性质.此外,新系统的公平交换子协议引入了分布式TTP,即考虑了拒绝服务攻击的风险.
文摘Objective:Entrustable professional activities(EPAs)is a newly emerging concept.This paper aims at analyzing the concept of"EPAs"to clarify the meaning and to identify its components for optimum understanding of the concept for use in nursing education and future research.Method:Three databases-ProQuest,Ovid,and PubMed-were retrieved,and Walker and Avant's concept analysis approach was used to analyze the concept of EPAs.Results:Based on the analysis,three attributes of EPAs were defined,namely (1)EPAs should be restricted to a limited number of tasks;(2)reflect the experience curve;and (3)include acceptance of responsibility and accountability.The antecedent of EPAs is a holistic and integrated assessment approach.This will eventually lead to anticipated consequences such as a mastery of core competencies and an increase in the level of autonomy.Conclusion:The study may contribute to a reduction in the ambiguity of this concept to better apply it in nursing practice.
文摘After analysis of the existing problems of traditional RBAC model, user group and resource domain are introduced to conduct finely granular extension of RBAC model. Extended model reduces the redundancy of roles, lowers the complexity of authorization management and enhances the flexibility and maintainability of users＇ authorization. It is well proved in its application in postgraduate student management system.
