Access control is an important protection mechanism for information systems. This paper shows how to make access control in workflow system. We give a workflow access control model (WACM) based on several current acce...Access control is an important protection mechanism for information systems. This paper shows how to make access control in workflow system. We give a workflow access control model (WACM) based on several current access control models. The model supports roles assignment and dynamic authorization. The paper defines the workflow using Petri net. It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM). Finally, an example of an e-commerce workflow access control model is discussed in detail.展开更多
Pattern division multiple access(PDMA),which is a novel non-orthogonal multiple access(NOMA),has been proposed to address the challenges of massive connectivity and higher spectral efficiency for fifth generation(5G) ...Pattern division multiple access(PDMA),which is a novel non-orthogonal multiple access(NOMA),has been proposed to address the challenges of massive connectivity and higher spectral efficiency for fifth generation(5G) mobile network.The performance of PDMA mainly depends on the design of PDMA pattern matrix.In this paper,pattern matrix design of PDMA for 5G uplink(UL) applications in massive machine type communication(mMTC) and enhanced mobile broadband(eMBB) deployment scenarios are studied.The design criteria and examples for application in UL mMTC and UL eMBB are investigated.The performance of the PDMA pattern matrix is analyzed with the discrete constellation constrained capacity(CC-Capacity),and verified by Monte Carlo simulation.The simulation results show that the preferred PDMA pattern matrix can achieve good performance with different overloading factors(OF).展开更多
In cognitive radio networks, the spectrum utilization can be improved by cognitive users opportunistically using the idle channels licensed to the primary users. However, the new arrived cognitive users may not be abl...In cognitive radio networks, the spectrum utilization can be improved by cognitive users opportunistically using the idle channels licensed to the primary users. However, the new arrived cognitive users may not be able to use the channel immediately since the channel usage state is random. This will impose additional time delay for the cognitive users. Excessive waiting delay can make cognitive users miss the spectrum access chances. In this paper, a discrete-time Markov queuing model from a macro point of view is provided. Through the matrix-geometric solution theory, the average sojourn time for cognitive users in the steady state before accessing the spectrum is obtained. Given the tolerant delay of cognitive users, the macro-based throughput is derived and an access control mechanism is proposed. The numerical results show the effects of service completion probability on average sojourn time and throughput. It is confirmed that the throughput can be obviously improved by using the proposed access control mechanism. Finally, the performance evaluations based on users are compared to that based on data packets.展开更多
Over the past decade, Graphics Processing Units (GPUs) have revolutionized high-performance computing, playing pivotal roles in advancing fields like IoT, autonomous vehicles, and exascale computing. Despite these adv...Over the past decade, Graphics Processing Units (GPUs) have revolutionized high-performance computing, playing pivotal roles in advancing fields like IoT, autonomous vehicles, and exascale computing. Despite these advancements, efficiently programming GPUs remains a daunting challenge, often relying on trial-and-error optimization methods. This paper introduces an optimization technique for CUDA programs through a novel Data Layout strategy, aimed at restructuring memory data arrangement to significantly enhance data access locality. Focusing on the dynamic programming algorithm for chained matrix multiplication—a critical operation across various domains including artificial intelligence (AI), high-performance computing (HPC), and the Internet of Things (IoT)—this technique facilitates more localized access. We specifically illustrate the importance of efficient matrix multiplication in these areas, underscoring the technique’s broader applicability and its potential to address some of the most pressing computational challenges in GPU-accelerated applications. Our findings reveal a remarkable reduction in memory consumption and a substantial 50% decrease in execution time for CUDA programs utilizing this technique, thereby setting a new benchmark for optimization in GPU computing.展开更多
动态策略支持与授权粒度是访问控制的关键问题.现有的研究只关注安全策略的描述能力,却忽略了对策略结构与授权粒度的分析,从而无法全面满足动态策略支持与最小授权要求.指出Lampson访问矩阵模型是对最细粒度访问控制的抽象,普通安全策...动态策略支持与授权粒度是访问控制的关键问题.现有的研究只关注安全策略的描述能力,却忽略了对策略结构与授权粒度的分析,从而无法全面满足动态策略支持与最小授权要求.指出Lampson访问矩阵模型是对最细粒度访问控制的抽象,普通安全策略则根据应用安全需求对Lampson访问矩阵进行聚合.基于安全标签的聚合性描述框架(a descriptive framework of groupability basing on security labels,简称GroSeLa)可将普通安全策略映射为Lampson访问矩阵,该框架分为基本组件与扩展两部分:前者分析用于实现矩阵聚合的安全策略结构;后者则指出实现全面动态策略支持必须支持的7类管理性需求.在此基础上,提出5项聚合性指标:聚合因子、动态因子、策略规模、授权粒度与职责隔离支持.对4类经典安全策略ACL,BLP,DTE与RBAC的评估,是从矩阵聚合的角度分析不同的安全策略在表达性、可用性与授权粒度上的差异.展开更多
文摘Access control is an important protection mechanism for information systems. This paper shows how to make access control in workflow system. We give a workflow access control model (WACM) based on several current access control models. The model supports roles assignment and dynamic authorization. The paper defines the workflow using Petri net. It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM). Finally, an example of an e-commerce workflow access control model is discussed in detail.
基金supported by the National High Technology Research and Development Program of China(863 Program,No. 2015AA01A709)
文摘Pattern division multiple access(PDMA),which is a novel non-orthogonal multiple access(NOMA),has been proposed to address the challenges of massive connectivity and higher spectral efficiency for fifth generation(5G) mobile network.The performance of PDMA mainly depends on the design of PDMA pattern matrix.In this paper,pattern matrix design of PDMA for 5G uplink(UL) applications in massive machine type communication(mMTC) and enhanced mobile broadband(eMBB) deployment scenarios are studied.The design criteria and examples for application in UL mMTC and UL eMBB are investigated.The performance of the PDMA pattern matrix is analyzed with the discrete constellation constrained capacity(CC-Capacity),and verified by Monte Carlo simulation.The simulation results show that the preferred PDMA pattern matrix can achieve good performance with different overloading factors(OF).
文摘In cognitive radio networks, the spectrum utilization can be improved by cognitive users opportunistically using the idle channels licensed to the primary users. However, the new arrived cognitive users may not be able to use the channel immediately since the channel usage state is random. This will impose additional time delay for the cognitive users. Excessive waiting delay can make cognitive users miss the spectrum access chances. In this paper, a discrete-time Markov queuing model from a macro point of view is provided. Through the matrix-geometric solution theory, the average sojourn time for cognitive users in the steady state before accessing the spectrum is obtained. Given the tolerant delay of cognitive users, the macro-based throughput is derived and an access control mechanism is proposed. The numerical results show the effects of service completion probability on average sojourn time and throughput. It is confirmed that the throughput can be obviously improved by using the proposed access control mechanism. Finally, the performance evaluations based on users are compared to that based on data packets.
文摘Over the past decade, Graphics Processing Units (GPUs) have revolutionized high-performance computing, playing pivotal roles in advancing fields like IoT, autonomous vehicles, and exascale computing. Despite these advancements, efficiently programming GPUs remains a daunting challenge, often relying on trial-and-error optimization methods. This paper introduces an optimization technique for CUDA programs through a novel Data Layout strategy, aimed at restructuring memory data arrangement to significantly enhance data access locality. Focusing on the dynamic programming algorithm for chained matrix multiplication—a critical operation across various domains including artificial intelligence (AI), high-performance computing (HPC), and the Internet of Things (IoT)—this technique facilitates more localized access. We specifically illustrate the importance of efficient matrix multiplication in these areas, underscoring the technique’s broader applicability and its potential to address some of the most pressing computational challenges in GPU-accelerated applications. Our findings reveal a remarkable reduction in memory consumption and a substantial 50% decrease in execution time for CUDA programs utilizing this technique, thereby setting a new benchmark for optimization in GPU computing.
文摘动态策略支持与授权粒度是访问控制的关键问题.现有的研究只关注安全策略的描述能力,却忽略了对策略结构与授权粒度的分析,从而无法全面满足动态策略支持与最小授权要求.指出Lampson访问矩阵模型是对最细粒度访问控制的抽象,普通安全策略则根据应用安全需求对Lampson访问矩阵进行聚合.基于安全标签的聚合性描述框架(a descriptive framework of groupability basing on security labels,简称GroSeLa)可将普通安全策略映射为Lampson访问矩阵,该框架分为基本组件与扩展两部分:前者分析用于实现矩阵聚合的安全策略结构;后者则指出实现全面动态策略支持必须支持的7类管理性需求.在此基础上,提出5项聚合性指标:聚合因子、动态因子、策略规模、授权粒度与职责隔离支持.对4类经典安全策略ACL,BLP,DTE与RBAC的评估,是从矩阵聚合的角度分析不同的安全策略在表达性、可用性与授权粒度上的差异.
