本文基于主导逻辑演进和"投入-产出"视角阐释产品价值生态系统的概念和本质,提出产品价值生态系统的概念模型.以实体制造和无形服务协同为出发点,分析指出子系统内硬软要素的组合协同、各子系统间的交互协同和"系统-环境生态"间的匹配协同是构成产品价值生态系统的主要协同创造机制,据此提出生产性服务与制造价值链协同、实体硬件产品与软件服务协同和基于互联网的平台整合协同等系列子系统内价值升级路径和子系统间的价值升级路径,以期为我国制造业升级提供意见参考.

Cluster has become a new generation of distributed system. Among the server cluster technologies, request distribution technology is used to distribute requests among server nodes, providing support to large-scale concurrent access to server cluster. In order to overcome the weakness of existing request distribution strategies for server cluster in average response time and computation cost, this paper proposes a request distribution strategy based on static time interval. Its basic idea is that it divides the update interval into several subintervals and introduces randomness into the selection of server node for the requests arrived in a subinterval. We give an implementation of the strategy and use MATLAB as the simulation platform to carry out simulation experiments in testing the performance of the strategy. Our theoretical analysis and experimental results show that, the strategy we propose achieves shorter average waiting time, more convenient implementation and lower computation cost than other several existing request distribution strategies.

For the load balancing problem of cluster system,an improved dynamic load balancing strategy based on feedback is introduced.Combined with periodic feedback theory,the strategy divides update interval into several equal subintervals,and adopts a random mechanism to distribute requests in each subinterval.The model of the process of cluster system is founded based on queuing theory and the formula for calculating the system performance is obtained.Simulation results show that,compared with Aggressive LI strategy,this strategy can attain equivalent performance at the expense of smaller cost,and has small complexity of implementation.