By conducting relative permeability experiments of multi-cycle gas-water displacement and imbibition on natural cores,we discuss relative permeability hysteresis effect in underground gas storage during multi-cycle in...By conducting relative permeability experiments of multi-cycle gas-water displacement and imbibition on natural cores,we discuss relative permeability hysteresis effect in underground gas storage during multi-cycle injection and production.A correction method for relative permeability hysteresis in numerical simulation of water-invaded gas storage has been worked out using the Carlson and Killough models.A geologic model of water-invaded sandstone gas storage with medium-low permeability is built to investigate the impacts of relative permeability hysteresis on fluid distribution and production performance during multi-cycle injection and production of the gas storage.The study shows that relative permeability hysteresis effect occurs during high-speed injection and production in gas storage converted from water-invaded gas reservoir,and leads to increase of gas-water transition zone width and thickness,shrinkage of the area of high-efficiency gas storage,and decrease of the peak value variation of pore volume containing gas,and then reduces the storage capacity,working gas volume,and high-efficiency operation span of the gas storage.Numerical simulations exhibit large prediction errors of performance indexes if this hysteresis effect is not considered.Killough and Carlson methods can be used to correct the relative permeability hysteresis effect in water-invaded underground gas storage to improve the prediction accuracy.The Killough method has better adaptability to the example model.展开更多
Pipeline processing is applied to mutiple flow tables(MFT)in the switch of software-defined network(SDN)to increase the throughput of the flows.However,the processing time of each flow increases as the size or number ...Pipeline processing is applied to mutiple flow tables(MFT)in the switch of software-defined network(SDN)to increase the throughput of the flows.However,the processing time of each flow increases as the size or number of flow tables gets larger.In this paper we propose a novel approach called PopFlow where a table keeping popular flow entries is located up front in the pipeline,and an express path is provided for the flow matching the table.A Markov model is employed for the selection of popular entries considering the match latency and match frequency,and Queuing theory is used to model the flow processing time of the existing MFT-based schemes and the proposed scheme.Computer simulation reveals that the proposed scheme substantially reduces the flow processing time compared to the existing schemes,and the diference gets more significant as the flow arrival rate increases.展开更多
In this paper we aim to analyse temporal variation of CD4 cell counts for HIV-infected individuals under antiretroviral therapy by using statistical methods. This is achieved by resorting to recursive binary regressio...In this paper we aim to analyse temporal variation of CD4 cell counts for HIV-infected individuals under antiretroviral therapy by using statistical methods. This is achieved by resorting to recursive binary regression tree approach [1]?[2]. This approach has made it possible to highlight the existence of several segments of the population of interest described by the interactions between the predictive covariates of the response to the treatment regimen.展开更多
基金Supported by the Petro China Science and Technology Major Project(2015E-4002)。
文摘By conducting relative permeability experiments of multi-cycle gas-water displacement and imbibition on natural cores,we discuss relative permeability hysteresis effect in underground gas storage during multi-cycle injection and production.A correction method for relative permeability hysteresis in numerical simulation of water-invaded gas storage has been worked out using the Carlson and Killough models.A geologic model of water-invaded sandstone gas storage with medium-low permeability is built to investigate the impacts of relative permeability hysteresis on fluid distribution and production performance during multi-cycle injection and production of the gas storage.The study shows that relative permeability hysteresis effect occurs during high-speed injection and production in gas storage converted from water-invaded gas reservoir,and leads to increase of gas-water transition zone width and thickness,shrinkage of the area of high-efficiency gas storage,and decrease of the peak value variation of pore volume containing gas,and then reduces the storage capacity,working gas volume,and high-efficiency operation span of the gas storage.Numerical simulations exhibit large prediction errors of performance indexes if this hysteresis effect is not considered.Killough and Carlson methods can be used to correct the relative permeability hysteresis effect in water-invaded underground gas storage to improve the prediction accuracy.The Killough method has better adaptability to the example model.
基金supported by Institute for In-fornation&communications Technology Promotion(ITP)grant funded by the Korea government(MSIT)(2016-0-00133,Research on Edge computing via collctive intelligence of hyperconnection IoT nodes)Korea,under the National Program for Excellence in Sw supervised by the ITP(Institute for Information&communications Technology Promotion)(2015-0-00914)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(2016R1A6A3A11931385,Research of key technologies based on software defined wireless sensor network for realtime public safety service,2017R1A2B2009095,Research on SDN-based WSN Supporting Real-time Stream Data Processing and Multi-connectivity,2019R1I1A1A01058780,Eficient Management of SDN-based Wireless Sensor Network Using Machine Learning Technique),the second Brain Korea 21 PLUS project.
文摘Pipeline processing is applied to mutiple flow tables(MFT)in the switch of software-defined network(SDN)to increase the throughput of the flows.However,the processing time of each flow increases as the size or number of flow tables gets larger.In this paper we propose a novel approach called PopFlow where a table keeping popular flow entries is located up front in the pipeline,and an express path is provided for the flow matching the table.A Markov model is employed for the selection of popular entries considering the match latency and match frequency,and Queuing theory is used to model the flow processing time of the existing MFT-based schemes and the proposed scheme.Computer simulation reveals that the proposed scheme substantially reduces the flow processing time compared to the existing schemes,and the diference gets more significant as the flow arrival rate increases.
文摘In this paper we aim to analyse temporal variation of CD4 cell counts for HIV-infected individuals under antiretroviral therapy by using statistical methods. This is achieved by resorting to recursive binary regression tree approach [1]?[2]. This approach has made it possible to highlight the existence of several segments of the population of interest described by the interactions between the predictive covariates of the response to the treatment regimen.
