To reduce network redundancy,innetwork caching is considered in many future Internet architectures,such as Information Centric Networking.In in-network caching system,the item sojourn time of LRU(Least Recently Used) ...To reduce network redundancy,innetwork caching is considered in many future Internet architectures,such as Information Centric Networking.In in-network caching system,the item sojourn time of LRU(Least Recently Used) replacement policy is an important issue for two reasons:firstly,LRU is one of the most common used cache policy;secondly,item sojourn time is positively correlated to the hit probability,so this metric parameter could be useful to design the caching system.However,to the best of our knowledge,the sojourn time hasn't been studied theoretically so far.In this paper,we first model the LRU cache policy by Markov chain.Then an approximate closedform expression of the item expectation sojourn time is provided through the theory of stochastic service system,which is a function of the item request rates and cache size.Finally,extensive simulation results are illustrated to show that the expression is a good approximation of the item sojourn time.展开更多
In this paper we devote ourselves to extending Berman’s sojourn time method,which is thoroughly described in[1-3],to investigate the tail asymptotics of the extrema of a Gaussian random field over[0,T]^(d) with T∈(0...In this paper we devote ourselves to extending Berman’s sojourn time method,which is thoroughly described in[1-3],to investigate the tail asymptotics of the extrema of a Gaussian random field over[0,T]^(d) with T∈(0,∞).展开更多
The Distributed Queue Dual Bus(DQDB) Metropolitan Area Network(MAN) is a promising solution for the evolution from current networks to B-ISDN. The performance of the DQDB MAN for Local Area Networks(LANs) interconnect...The Distributed Queue Dual Bus(DQDB) Metropolitan Area Network(MAN) is a promising solution for the evolution from current networks to B-ISDN. The performance of the DQDB MAN for Local Area Networks(LANs) interconnection is analyzed. The effects of message length, traffic load of upstream and downstream nodes and the parameters of bandwidth balancing mechanism and network counters on the sojourn time of message in the buffer are investigated, which present a valuable reference for the implementation of the DQDB MAN.展开更多
In many service delivery systems,the quantity of available resources is often a decisive factor of service quality.Resources can be personnel,offices,devices,supplies,and so on,depending on the nature of the services ...In many service delivery systems,the quantity of available resources is often a decisive factor of service quality.Resources can be personnel,offices,devices,supplies,and so on,depending on the nature of the services a system provides.Although service computing has been an active research topic for decades,general approaches that assess the impact of resource provisioning on service quality matrices in a rigorous way remain to be seen.Petri nets have been a popular formalism for modeling systems exhibiting behaviors of competition and concurrency for almost a half century.Stochastic timed Petri nets(STPN),an extension to regular Petri nets,are a powerful tool for system performance evaluation.However,we did not find any single existing STPN software tool that supports all timed transition firing policies and server types,not to mention resource provisioning and requirement analysis.This paper presents a generic and resource oriented STPN simulation engine that provides all critical features necessary for the analysis of service delivery system quality vs.resource provisioning.The power of the simulation system is illustrated by an application to emergency health care systems.展开更多
文摘To reduce network redundancy,innetwork caching is considered in many future Internet architectures,such as Information Centric Networking.In in-network caching system,the item sojourn time of LRU(Least Recently Used) replacement policy is an important issue for two reasons:firstly,LRU is one of the most common used cache policy;secondly,item sojourn time is positively correlated to the hit probability,so this metric parameter could be useful to design the caching system.However,to the best of our knowledge,the sojourn time hasn't been studied theoretically so far.In this paper,we first model the LRU cache policy by Markov chain.Then an approximate closedform expression of the item expectation sojourn time is provided through the theory of stochastic service system,which is a function of the item request rates and cache size.Finally,extensive simulation results are illustrated to show that the expression is a good approximation of the item sojourn time.
基金partially supported by National Natural Science Foundation of China(11701070,71871046)Ronglian Scholarship Fund.
文摘In this paper we devote ourselves to extending Berman’s sojourn time method,which is thoroughly described in[1-3],to investigate the tail asymptotics of the extrema of a Gaussian random field over[0,T]^(d) with T∈(0,∞).
基金Supported by the National Natural Science Foundation of Chinathe Foundation of the Institute of Electronic Science of China
文摘The Distributed Queue Dual Bus(DQDB) Metropolitan Area Network(MAN) is a promising solution for the evolution from current networks to B-ISDN. The performance of the DQDB MAN for Local Area Networks(LANs) interconnection is analyzed. The effects of message length, traffic load of upstream and downstream nodes and the parameters of bandwidth balancing mechanism and network counters on the sojourn time of message in the buffer are investigated, which present a valuable reference for the implementation of the DQDB MAN.
文摘In many service delivery systems,the quantity of available resources is often a decisive factor of service quality.Resources can be personnel,offices,devices,supplies,and so on,depending on the nature of the services a system provides.Although service computing has been an active research topic for decades,general approaches that assess the impact of resource provisioning on service quality matrices in a rigorous way remain to be seen.Petri nets have been a popular formalism for modeling systems exhibiting behaviors of competition and concurrency for almost a half century.Stochastic timed Petri nets(STPN),an extension to regular Petri nets,are a powerful tool for system performance evaluation.However,we did not find any single existing STPN software tool that supports all timed transition firing policies and server types,not to mention resource provisioning and requirement analysis.This paper presents a generic and resource oriented STPN simulation engine that provides all critical features necessary for the analysis of service delivery system quality vs.resource provisioning.The power of the simulation system is illustrated by an application to emergency health care systems.
