已有的LRFU(Least Recency Frequency Used)自适应算法在实际应用中根据经验调整λ值,缺乏对访问局部性强弱的量化分析,因而其可适用的访问模式有限.该文首先建立基于K阶马尔可夫链(K→∞)的局部性定量分析模型,在访问过程中根据统计信...已有的LRFU(Least Recency Frequency Used)自适应算法在实际应用中根据经验调整λ值,缺乏对访问局部性强弱的量化分析,因而其可适用的访问模式有限.该文首先建立基于K阶马尔可夫链(K→∞)的局部性定量分析模型,在访问过程中根据统计信息实时量化局部性特征.然后以此分析模型为基础设计自适应替换算法LA-LRFU(Locality-Aware LRFU),随着访问特征的变化动态调整参数λ.最后应用Trace仿真对算法进行测试.实验结果显示,针对多种访问模式,LA-LRFU均可显著提高Cache命中率;在由多种访问模式构成的具体访问过程中,LA-LRFU能比现有的各类LRFU自适应算法更合理地调整参数λ.展开更多
Role based access control is one of the widely used access control models.There are investigations in the literature that use knowledge representation mechanisms such as formal concept analysis(FCA),description logics...Role based access control is one of the widely used access control models.There are investigations in the literature that use knowledge representation mechanisms such as formal concept analysis(FCA),description logics,and Ontology for representing access control mechanism.However,while using FCA,investigations reported in the literature so far work on the logic that transforms the three dimensional access control matrix into dyadic formal contexts.This transformation is mainly to derive the formal concepts,lattice structure and implications to represent role hierarchy and constraints of RBAC.In this work,we propose a methodology that models RBAC using triadic FCA without transforming the triadic access control matrix into dyadic formal contexts.Our discussion is on two lines of inquiry.We present how triadic FCA can provide a suitable representation of RBAC policy and we demonstrate how this representation follows role hierarchy and constraints of RBAC on sample healthcare network available in the literature.展开更多
文摘已有的LRFU(Least Recency Frequency Used)自适应算法在实际应用中根据经验调整λ值,缺乏对访问局部性强弱的量化分析,因而其可适用的访问模式有限.该文首先建立基于K阶马尔可夫链(K→∞)的局部性定量分析模型,在访问过程中根据统计信息实时量化局部性特征.然后以此分析模型为基础设计自适应替换算法LA-LRFU(Locality-Aware LRFU),随着访问特征的变化动态调整参数λ.最后应用Trace仿真对算法进行测试.实验结果显示,针对多种访问模式,LA-LRFU均可显著提高Cache命中率;在由多种访问模式构成的具体访问过程中,LA-LRFU能比现有的各类LRFU自适应算法更合理地调整参数λ.
基金the financial support from Department of Science and Technology,Government of India under the grant:SR/CSRI/118/2014
文摘Role based access control is one of the widely used access control models.There are investigations in the literature that use knowledge representation mechanisms such as formal concept analysis(FCA),description logics,and Ontology for representing access control mechanism.However,while using FCA,investigations reported in the literature so far work on the logic that transforms the three dimensional access control matrix into dyadic formal contexts.This transformation is mainly to derive the formal concepts,lattice structure and implications to represent role hierarchy and constraints of RBAC.In this work,we propose a methodology that models RBAC using triadic FCA without transforming the triadic access control matrix into dyadic formal contexts.Our discussion is on two lines of inquiry.We present how triadic FCA can provide a suitable representation of RBAC policy and we demonstrate how this representation follows role hierarchy and constraints of RBAC on sample healthcare network available in the literature.
