In this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater Gliders(BWBUGs)is proposed to reduce the computational cost.In this strategy,a double-stage surrogate mode...In this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater Gliders(BWBUGs)is proposed to reduce the computational cost.In this strategy,a double-stage surrogate model is developed to replace the high-dimensional objective in shape optimization.Specifically,several First-stage Surrogate Models(FSMs)are built for the sectional airfoils,and the second-stage surrogate model is constructed with respect to the outputs of FSMs.Besides,a Multi-start Space Reduction surrogate-based global optimization method is applied to search for the optimum.In order to validate the efficiency of the proposed method,DSSO is first compared with an ordinary One-stage Surrogate-based Optimization strategy by using the same optimization method.Then,the other three popular surrogate-based optimization methods and three heuristic algorithms are utilized to make comparisons.Results indicate that the lift-to-drag ratio of the BWBUG is improved by 9.35%with DSSO,which outperforms the comparison methods.Besides,DSSO reduces more than 50%of the time that other methods used when obtaining the same level of results.Furthermore,some considerations of the proposed strategy are further discussed and some characteristics of DSSO are identified.展开更多
Collar rot caused the death of Hevea rubber in a village located in Jino County of Xishuangbanna in September, 2012. In order to elucidate the causal agent of collar rot and its taxonomic status, the causal fungus was...Collar rot caused the death of Hevea rubber in a village located in Jino County of Xishuangbanna in September, 2012. In order to elucidate the causal agent of collar rot and its taxonomic status, the causal fungus was isolated and identified through a series of tests about its pathogenicity, morphology, culture feature and biological characteristics. The results indicated that the fungus was Fusarium venfrico- sum. It could grow at temperatures ranging from 10 to 40 ℃, and the most suitable temperature was 30 ℃. Its mycelium growth was inhibited above 40 ℃ or below 10 ℃. The accumulated water in wet season was the main reason for this disease occurrence.展开更多
基金This research was financially supported by the National Natural Science Foundation of China(Grant Nos.51875466 and 51805436)the China Postdoctoral Science Foundation(Grant No.2019T120941)the China Scholarships Council(Grant No.201806290133).
文摘In this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater Gliders(BWBUGs)is proposed to reduce the computational cost.In this strategy,a double-stage surrogate model is developed to replace the high-dimensional objective in shape optimization.Specifically,several First-stage Surrogate Models(FSMs)are built for the sectional airfoils,and the second-stage surrogate model is constructed with respect to the outputs of FSMs.Besides,a Multi-start Space Reduction surrogate-based global optimization method is applied to search for the optimum.In order to validate the efficiency of the proposed method,DSSO is first compared with an ordinary One-stage Surrogate-based Optimization strategy by using the same optimization method.Then,the other three popular surrogate-based optimization methods and three heuristic algorithms are utilized to make comparisons.Results indicate that the lift-to-drag ratio of the BWBUG is improved by 9.35%with DSSO,which outperforms the comparison methods.Besides,DSSO reduces more than 50%of the time that other methods used when obtaining the same level of results.Furthermore,some considerations of the proposed strategy are further discussed and some characteristics of DSSO are identified.
文摘Collar rot caused the death of Hevea rubber in a village located in Jino County of Xishuangbanna in September, 2012. In order to elucidate the causal agent of collar rot and its taxonomic status, the causal fungus was isolated and identified through a series of tests about its pathogenicity, morphology, culture feature and biological characteristics. The results indicated that the fungus was Fusarium venfrico- sum. It could grow at temperatures ranging from 10 to 40 ℃, and the most suitable temperature was 30 ℃. Its mycelium growth was inhibited above 40 ℃ or below 10 ℃. The accumulated water in wet season was the main reason for this disease occurrence.
