This paper addresses the problem of optimal operation in long-term crude oil scheduling,which involves unloading crude oil from vessels,transferring it to charging tanks and feeding it to the distillation units.The ap...This paper addresses the problem of optimal operation in long-term crude oil scheduling,which involves unloading crude oil from vessels,transferring it to charging tanks and feeding it to the distillation units.The application of a new approach for modeling and optimization of long-term crude oil scheduling is presented and the event-tree based modeling method that is very different from mathematical programming is employed.This approach is developed on the basis of natural language modeling and continuous time representation.Event triggered rules,decomposition strategy,depth-first search algorithm and pruning strategy are adopted to improve the efficiency of searching the optimum solution.This approach is successfully applied to an industrial-size problem over a horizon of 4 weeks,involving 7 vessels,6 storage tanks,6 charging tanks,2 crude oil distillation units,and 6 crude oil types.The CPU (AMD 3000+,2.0GHz) solving time is less than 70 seconds.展开更多
While there is high confidence that human activities have increased the likelihood and severity of hot extreme events over many parts of the world,there is notable spread in quantitative estimates of anthropogenic inf...While there is high confidence that human activities have increased the likelihood and severity of hot extreme events over many parts of the world,there is notable spread in quantitative estimates of anthropogenic influence even on a single event.To better understand the uncertainty of attribution results,here we compare different event attribution methods using the 2015 July-August record-breaking heat event in northwestern China as a case study.To address the anthropogenic influence on the likelihood of the extreme event,we employ attribution runs with two modeling strategies—atmosphere-only and coupled simulations—with different conditioning.In atmosphere-only attribution runs,given the observed sea surface boundary conditions and external forcings in 2015,it is estimated that anthropogenic forcing has increased the likelihood of hot extremes such as that observed in 2015 in the target region,by approximately 27 and 12 times in MIROC5 and HadGEM3-A-N216,respectively.In Coupled Model Intercomparison Project phase 5(CMIP5)fully coupled attribution runs,given the external forcing at the 1961-2015 level and regardless of sea surface boundary conditions,there is a 21-fold increase in the likelihood of similar heat events due to anthropogenic forcing.The differences in quantitative attribution results can arise from modeling strategies,which are tightly linked to different conditioning in attribution.Specifically,different ocean boundary conditions,external forcings,and air-sea coupling processes contribute to different attribution results between the two modeling strategies.Within each modeling strategy,model uncertainty affects quantitative attribution conclusions.The comparison of different attribution methods provides a better understanding of the uncertainty of attribution results,which is useful in synthesizing and interpreting attribution results.展开更多
The current DSA system used in the dispatching control centers in China is a near real-time analysis system with response speed in the order of minutes.Based on a review of the state-of-the-art in online analysis and ...The current DSA system used in the dispatching control centers in China is a near real-time analysis system with response speed in the order of minutes.Based on a review of the state-of-the-art in online analysis and discussion of distributed data processing and computation architecture patterns,a new online analysis architecture is proposed.The primary goal of the new architecture is to increase the online analysis response speed to the order of seconds.A reference implementation of the proposed online analysis architecture to validate the feasibility of implementing the architecture and some performance testing results are presented.展开更多
文摘This paper addresses the problem of optimal operation in long-term crude oil scheduling,which involves unloading crude oil from vessels,transferring it to charging tanks and feeding it to the distillation units.The application of a new approach for modeling and optimization of long-term crude oil scheduling is presented and the event-tree based modeling method that is very different from mathematical programming is employed.This approach is developed on the basis of natural language modeling and continuous time representation.Event triggered rules,decomposition strategy,depth-first search algorithm and pruning strategy are adopted to improve the efficiency of searching the optimum solution.This approach is successfully applied to an industrial-size problem over a horizon of 4 weeks,involving 7 vessels,6 storage tanks,6 charging tanks,2 crude oil distillation units,and 6 crude oil types.The CPU (AMD 3000+,2.0GHz) solving time is less than 70 seconds.
基金Supported by the National Key Research and Development Program of China(2018YFC1507701)。
文摘While there is high confidence that human activities have increased the likelihood and severity of hot extreme events over many parts of the world,there is notable spread in quantitative estimates of anthropogenic influence even on a single event.To better understand the uncertainty of attribution results,here we compare different event attribution methods using the 2015 July-August record-breaking heat event in northwestern China as a case study.To address the anthropogenic influence on the likelihood of the extreme event,we employ attribution runs with two modeling strategies—atmosphere-only and coupled simulations—with different conditioning.In atmosphere-only attribution runs,given the observed sea surface boundary conditions and external forcings in 2015,it is estimated that anthropogenic forcing has increased the likelihood of hot extremes such as that observed in 2015 in the target region,by approximately 27 and 12 times in MIROC5 and HadGEM3-A-N216,respectively.In Coupled Model Intercomparison Project phase 5(CMIP5)fully coupled attribution runs,given the external forcing at the 1961-2015 level and regardless of sea surface boundary conditions,there is a 21-fold increase in the likelihood of similar heat events due to anthropogenic forcing.The differences in quantitative attribution results can arise from modeling strategies,which are tightly linked to different conditioning in attribution.Specifically,different ocean boundary conditions,external forcings,and air-sea coupling processes contribute to different attribution results between the two modeling strategies.Within each modeling strategy,model uncertainty affects quantitative attribution conclusions.The comparison of different attribution methods provides a better understanding of the uncertainty of attribution results,which is useful in synthesizing and interpreting attribution results.
基金This work was supported by the State Grid of China under the“Thousand Talents Plan”special research grant(5206001600A3).
文摘The current DSA system used in the dispatching control centers in China is a near real-time analysis system with response speed in the order of minutes.Based on a review of the state-of-the-art in online analysis and discussion of distributed data processing and computation architecture patterns,a new online analysis architecture is proposed.The primary goal of the new architecture is to increase the online analysis response speed to the order of seconds.A reference implementation of the proposed online analysis architecture to validate the feasibility of implementing the architecture and some performance testing results are presented.
