聚合流量是在云计算环境下由多个网络用户数据源叠加后产生的一种聚合流。云计算存在高并发性,在多个服务同时请求接入网络时,传统的单流的接纳控制方法只能处理一个请求,其他服务要等前面的流被处理完才能接受服务,当并发请求的服务越...聚合流量是在云计算环境下由多个网络用户数据源叠加后产生的一种聚合流。云计算存在高并发性,在多个服务同时请求接入网络时,传统的单流的接纳控制方法只能处理一个请求,其他服务要等前面的流被处理完才能接受服务,当并发请求的服务越多,等待的延迟也就越大,用户的体验效果也就越差。为了提升网络并发处理的能力,以进一步提高云计算的QoS,提出一种基于聚合流的有效带宽(effective bandwidth for aggregate flow,EBAF)接纳控制算法,通过估计聚合流所需的带宽来执行接纳控制,能同时处理多个服务请求。实验结果表明,EBAF算法的接纳能力相对传统的单流的接纳控制方法能较大的提高云计算服务保证质量。展开更多
In this study, the developments in modeling gas-phase catalyzed olefin polymerization fluidized-bed reactors （FBR） using Ziegler-Natta catalyst is presented. The modified mathematical model to account for mass and h...In this study, the developments in modeling gas-phase catalyzed olefin polymerization fluidized-bed reactors （FBR） using Ziegler-Natta catalyst is presented. The modified mathematical model to account for mass and heat transfer between the solid particles and the surrounding gas in the emulsion phase is developed in this work to include site activation reaction. This model developed in the present study is subsequently compared with well-known models, namely, the bubble-growth, well-mixed and the constant bubble size models for porous and non porous catalyst. The results we obtained from the model was very close to the constant bubble size model, well-mixed model and bubble growth model at the beginning of the reaction but its overall behavior changed and is closer to the well-mixed model compared with the bubble growth model and constant bubble size model after half an hour of operation. Neural-network based predictive controller are implemented to control the system and compared with the conventional PID controller, giving acceptable results.展开更多
文摘聚合流量是在云计算环境下由多个网络用户数据源叠加后产生的一种聚合流。云计算存在高并发性,在多个服务同时请求接入网络时,传统的单流的接纳控制方法只能处理一个请求,其他服务要等前面的流被处理完才能接受服务,当并发请求的服务越多,等待的延迟也就越大,用户的体验效果也就越差。为了提升网络并发处理的能力,以进一步提高云计算的QoS,提出一种基于聚合流的有效带宽(effective bandwidth for aggregate flow,EBAF)接纳控制算法,通过估计聚合流所需的带宽来执行接纳控制,能同时处理多个服务请求。实验结果表明,EBAF算法的接纳能力相对传统的单流的接纳控制方法能较大的提高云计算服务保证质量。
文摘In this study, the developments in modeling gas-phase catalyzed olefin polymerization fluidized-bed reactors （FBR） using Ziegler-Natta catalyst is presented. The modified mathematical model to account for mass and heat transfer between the solid particles and the surrounding gas in the emulsion phase is developed in this work to include site activation reaction. This model developed in the present study is subsequently compared with well-known models, namely, the bubble-growth, well-mixed and the constant bubble size models for porous and non porous catalyst. The results we obtained from the model was very close to the constant bubble size model, well-mixed model and bubble growth model at the beginning of the reaction but its overall behavior changed and is closer to the well-mixed model compared with the bubble growth model and constant bubble size model after half an hour of operation. Neural-network based predictive controller are implemented to control the system and compared with the conventional PID controller, giving acceptable results.
