So far, file access prediction models is mainly based on either the file access frequency or the historical record of the latest access. In this paper, a new file access prediction model called frequency- and recency-...So far, file access prediction models is mainly based on either the file access frequency or the historical record of the latest access. In this paper, a new file access prediction model called frequency- and recency-based successor (FRS) is presented which combines the advantages of the file frequency with the historical record. FRS model has the capability of rapid response to workload changes and can predict future events with greater accuracy than most of other prediction models. To evaluate the performance of FRS mode, the Linux kernel is modified to predict and prefetch upcoming accesses. The experiment shows that FRS can accurately predict approximately 80% of all file access events, while maintaining an immediate successor queue (ISQ) per-file which only requires regular dynamic updates.展开更多
A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified sce...A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified scenarios with one to two hops or multihop scenarios with a custody mechanism of the Bundle Protocol(BP).However,the research results are not applicable to communications in Complex Deep Space Networks(CDSNs)without the custody mechanism of BP that are more suitable for deep space communications with LTP.In this paper,we propose a model of file delivery time for LTP in CDSNs.Based on the model,we propose a Parameter Optimization Design Algorithm for LTP(LTP-PODA)of configuring reasonable parameters for LTP.The results show that the accuracy of the proposed model is at least 6.47%higher than that of the previously established models based on simple scenarios,and the proposed model is more suitable for CDSNs.Moreover,the LTP parameters are optimized by the LTP-PODA algorithm to obtain an optimization plan.Configuring the optimization plan for LTP improves the protocol transmission performance by at least 18.77%compared with configuring the other parameter configuration plans.展开更多
In this paper, we investigate pedestrian flows by using a newly-proposed cellular automaton (CA) model, which is based on the floor-field model. The interaction of pedestrians includes completion and cooperation, re...In this paper, we investigate pedestrian flows by using a newly-proposed cellular automaton (CA) model, which is based on the floor-field model. The interaction of pedestrians includes completion and cooperation, respectively reflected by a modified dynamic field and a position-changing behavior. Then we utilize this model to research lane formation phase in counter flow problem, involving the probability of lane formation phase, the average number of lanes and the microscopic behavior of pedestrians. It is found that the interaction between pedestrians and the different significant influences of average density of pedestrian flow on the features of lane formation phase.展开更多
基金Supported by Key Technology R&D Project Foundation of Sichuan Province (No.02GG006-018)
文摘So far, file access prediction models is mainly based on either the file access frequency or the historical record of the latest access. In this paper, a new file access prediction model called frequency- and recency-based successor (FRS) is presented which combines the advantages of the file frequency with the historical record. FRS model has the capability of rapid response to workload changes and can predict future events with greater accuracy than most of other prediction models. To evaluate the performance of FRS mode, the Linux kernel is modified to predict and prefetch upcoming accesses. The experiment shows that FRS can accurately predict approximately 80% of all file access events, while maintaining an immediate successor queue (ISQ) per-file which only requires regular dynamic updates.
基金supported by the Strategic Leading Project of the Chinese Academy of Sciences(No.XDA15014603).
文摘A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified scenarios with one to two hops or multihop scenarios with a custody mechanism of the Bundle Protocol(BP).However,the research results are not applicable to communications in Complex Deep Space Networks(CDSNs)without the custody mechanism of BP that are more suitable for deep space communications with LTP.In this paper,we propose a model of file delivery time for LTP in CDSNs.Based on the model,we propose a Parameter Optimization Design Algorithm for LTP(LTP-PODA)of configuring reasonable parameters for LTP.The results show that the accuracy of the proposed model is at least 6.47%higher than that of the previously established models based on simple scenarios,and the proposed model is more suitable for CDSNs.Moreover,the LTP parameters are optimized by the LTP-PODA algorithm to obtain an optimization plan.Configuring the optimization plan for LTP improves the protocol transmission performance by at least 18.77%compared with configuring the other parameter configuration plans.
基金Project supported by the National Natural Science Foun-dation of China(Grant No.11172164)the National Basic Re-search Development Program of China(973 Program,Grant No.2012CB725404)
文摘In this paper, we investigate pedestrian flows by using a newly-proposed cellular automaton (CA) model, which is based on the floor-field model. The interaction of pedestrians includes completion and cooperation, respectively reflected by a modified dynamic field and a position-changing behavior. Then we utilize this model to research lane formation phase in counter flow problem, involving the probability of lane formation phase, the average number of lanes and the microscopic behavior of pedestrians. It is found that the interaction between pedestrians and the different significant influences of average density of pedestrian flow on the features of lane formation phase.