The distribution of market shares within an industry is a relevant performance measure for managers and policy makers, for it allow to determine whether a given industry is competitive or not. Usually, the perfect com...The distribution of market shares within an industry is a relevant performance measure for managers and policy makers, for it allow to determine whether a given industry is competitive or not. Usually, the perfect competition model is the reference to judge the efficiency of markets. However, there is enough empirical evidence that shows that one of the most evident features of global firms is that both their size and market are Zipf-distributed. In this paper, we show that the distribution of market shares in the world cola-drink market is skewed, but it does not follow Zipf＇s law, thus it is inadequate to generalize it to any kind of market.展开更多
When examining the file transfer performance in a peer-to-peer file sharing system, a fundamental problem is how to describe the service rate for a file transfer. In this paper, the problem is examined by analyzing th...When examining the file transfer performance in a peer-to-peer file sharing system, a fundamental problem is how to describe the service rate for a file transfer. In this paper, the problem is examined by analyzing the distribution of server-like nodes' upstream-bandwidth among their concurrent transfers. A sufficient condition for the service rate, what a receiver obtains for downloading a file, to asymptotically be uniform is presented. On the aggregate service rate for transferring a file in a system, a sufficient condition for it to asymptotically follow a Zipf distribution is presented. These asymptotic equalities are both in the mean square sense. These analyses and the sufficient conditions provide a mathematic base for modeling file transfer processes in peer-to-peer file sharing systems.展开更多
The rapid development of MEC and 5G technology has aroused huge repercussions and aroused the attention of education and industry.The storage of educational resources,energy consumption and delays in use have become u...The rapid development of MEC and 5G technology has aroused huge repercussions and aroused the attention of education and industry.The storage of educational resources,energy consumption and delays in use have become urgent issues.In response to the above problems,this paper proposes a three-tier education network model and abstracts the network modeling.At the same time,the DQN method in reinforcement learning is used to solve the modeling method and simulation.Finally,the simulation results show that this method can effectively improve the cache hit rate and reduce the network load.展开更多
文摘The distribution of market shares within an industry is a relevant performance measure for managers and policy makers, for it allow to determine whether a given industry is competitive or not. Usually, the perfect competition model is the reference to judge the efficiency of markets. However, there is enough empirical evidence that shows that one of the most evident features of global firms is that both their size and market are Zipf-distributed. In this paper, we show that the distribution of market shares in the world cola-drink market is skewed, but it does not follow Zipf＇s law, thus it is inadequate to generalize it to any kind of market.
基金National High Technology Research and Development Program of China (No.2007AA01Z457)Shanghai Science and Technology Development Fundation,China(No.07QA14033)
文摘When examining the file transfer performance in a peer-to-peer file sharing system, a fundamental problem is how to describe the service rate for a file transfer. In this paper, the problem is examined by analyzing the distribution of server-like nodes' upstream-bandwidth among their concurrent transfers. A sufficient condition for the service rate, what a receiver obtains for downloading a file, to asymptotically be uniform is presented. On the aggregate service rate for transferring a file in a system, a sufficient condition for it to asymptotically follow a Zipf distribution is presented. These asymptotic equalities are both in the mean square sense. These analyses and the sufficient conditions provide a mathematic base for modeling file transfer processes in peer-to-peer file sharing systems.
文摘The rapid development of MEC and 5G technology has aroused huge repercussions and aroused the attention of education and industry.The storage of educational resources,energy consumption and delays in use have become urgent issues.In response to the above problems,this paper proposes a three-tier education network model and abstracts the network modeling.At the same time,the DQN method in reinforcement learning is used to solve the modeling method and simulation.Finally,the simulation results show that this method can effectively improve the cache hit rate and reduce the network load.
