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Some studies on stochastic optimization based quantitative risk management
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作者 HU Zhaolin 《运筹学学报(中英文)》 北大核心 2025年第3期135-159,共25页
Risk management often plays an important role in decision making un-der uncertainty.In quantitative risk management,assessing and optimizing risk metrics requires eficient computing techniques and reliable theoretical... Risk management often plays an important role in decision making un-der uncertainty.In quantitative risk management,assessing and optimizing risk metrics requires eficient computing techniques and reliable theoretical guarantees.In this pa-per,we introduce several topics on quantitative risk management and review some of the recent studies and advancements on the topics.We consider several risk metrics and study decision models that involve the metrics,with a main focus on the related com-puting techniques and theoretical properties.We show that stochastic optimization,as a powerful tool,can be leveraged to effectively address these problems. 展开更多
关键词 stochastic optimization quantitative risk management risk measure computing technique statistical property
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Multi-objective parameter optimization of abrasive water jet polishing for fused silica
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作者 LI Qian YAO Peng +6 位作者 DENG Hong-xing FENG Chen-yu XU Chong-hai QU Shuo-shuo YANG Yu-ying ZHU Hong-tao HUANG Chuan-zhen 《中国光学(中英文)》 北大核心 2025年第5期1185-1199,共15页
As a non-contact ultra-precision machining method,abrasive water jet polishing(AWJP)has signi-ficant application in optical elements processing due to its stable tool influence function(TIF),no subsurface damage and s... As a non-contact ultra-precision machining method,abrasive water jet polishing(AWJP)has signi-ficant application in optical elements processing due to its stable tool influence function(TIF),no subsurface damage and strong adaptability to workpiece shapes.In this study,the effects of jet pressure,nozzle diameter and impinging angle on the distribution of pressure,velocity and wall shear stress in the polishing flow field were systematically analyzed by computational fluid dynamics(CFD)simulation.Based on the Box-Behnken experimental design,a response surface regression model was constructed to investigate the influence mech-anism of process parameters on material removal rate(MRR)and surface roughness(Ra)of fused silica.And experimental results showed that increasing jet pressure and nozzle diameter significantly improved MRR,consistent with shear stress distribution revealed by CFD simulations.However,increasing jet pressure and impinging angle caused higher Ra values,which was unfavorable for surface quality improvement.Genetic algorithm(GA)was used for multi-objective optimization to establish Pareto solutions,achieving concurrent optimization of polishing efficiency and surface quality.A parameter combination of 2 MPa jet pressure,0.3 mm nozzle diameter,and 30°impinging angle achieved MRR of 169.05μm^(3)/s and Ra of 0.50 nm.Exper-imental verification showed prediction errors of 4.4%(MRR)and 3.8%(Ra),confirming the model’s reliabil-ity.This parameter optimization system provides theoretical basis and technical support for ultra-precision polishing of complex curved optical components. 展开更多
关键词 ABRASIVE computational fluid dynamics tool influence function material removal rate surface roughness
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An Algorithm for Cloud-based Web Service Combination Optimization Through Plant Growth Simulation
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作者 Li Qiang Qin Huawei +1 位作者 Qiao Bingqin Wu Ruifang 《系统仿真学报》 北大核心 2025年第2期462-473,共12页
In order to improve the efficiency of cloud-based web services,an improved plant growth simulation algorithm scheduling model.This model first used mathematical methods to describe the relationships between cloud-base... In order to improve the efficiency of cloud-based web services,an improved plant growth simulation algorithm scheduling model.This model first used mathematical methods to describe the relationships between cloud-based web services and the constraints of system resources.Then,a light-induced plant growth simulation algorithm was established.The performance of the algorithm was compared through several plant types,and the best plant model was selected as the setting for the system.Experimental results show that when the number of test cloud-based web services reaches 2048,the model being 2.14 times faster than PSO,2.8 times faster than the ant colony algorithm,2.9 times faster than the bee colony algorithm,and a remarkable 8.38 times faster than the genetic algorithm. 展开更多
关键词 cloud-based service scheduling algorithm resource constraint load optimization cloud computing plant growth simulation algorithm
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AI-driven Fourier Ptychography and Its Insight for“AI+Optics”(Invited)
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作者 PAN An WANG Aiye +4 位作者 FENG Tianci GAO Huiqin WANG Siyuan XU Jinghao LI Xuan 《光子学报》 北大核心 2025年第9期146-170,共25页
Fourier Ptychographic Microscopy(FPM)is a high-throughput computational optical imaging technology reported in 2013.It effectively breaks through the trade-off between high-resolution imaging and wide-field imaging.In... Fourier Ptychographic Microscopy(FPM)is a high-throughput computational optical imaging technology reported in 2013.It effectively breaks through the trade-off between high-resolution imaging and wide-field imaging.In recent years,it has been found that FPM is not only a tool to break through the trade-off between field of view and spatial resolution,but also a paradigm to break through those trade-off problems,thus attracting extensive attention.Compared with previous reviews,this review does not introduce its concept,basic principles,optical system and series of applications once again,but focuses on elaborating the three major difficulties faced by FPM technology in the process from“looking good”in the laboratory to“working well”in practical applications:mismatch between numerical model and physical reality,long reconstruction time and high computing power demand,and lack of multi-modal expansion.It introduces how to achieve key technological innovations in FPM through the dual drive of Artificial Intelligence(AI)and physics,including intelligent reconstruction algorithms introducing machine learning concepts,optical-algorithm co-design,fusion of frequency domain extrapolation methods and generative adversarial networks,multi-modal imaging schemes and data fusion enhancement,etc.,gradually solving the difficulties of FPM technology.Conversely,this review deeply considers the unique value of FPM technology in potentially feeding back to the development of“AI+optics”,such as providing AI benchmark tests under physical constraints,inspirations for the balance of computing power and bandwidth in miniaturized intelligent microscopes,and photoelectric hybrid architectures.Finally,it introduces the industrialization path and frontier directions of FPM technology,pointing out that with the promotion of the dual drive of AI and physics,it will generate a large number of industrial application case,and looks forward to the possibilities of future application scenarios and expansions,for instance,body fluid biopsy and point-of-care testing at the grassroots level represent the expansion of the growth market. 展开更多
关键词 Computational optical imaging Fourier ptychography Artificial Intelligence Highthroughput imaging Multimodal imaging
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A New Technique for Constructing Higher-order Iterative Methods to Solve Nonlinear Systems
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作者 XIAO Xiaoyong 《应用数学》 北大核心 2025年第3期762-774,共13页
In this paper,a new technique is introduced to construct higher-order iterative methods for solving nonlinear systems.The order of convergence of some iterative methods can be improved by three at the cost of introduc... In this paper,a new technique is introduced to construct higher-order iterative methods for solving nonlinear systems.The order of convergence of some iterative methods can be improved by three at the cost of introducing only one additional evaluation of the function in each step.Furthermore,some new efficient methods with a higher-order of convergence are obtained by using only a single matrix inversion in each iteration.Analyses of convergence properties and computational efficiency of these new methods are made and testified by several numerical problems.By comparison,the new schemes are more efficient than the corresponding existing ones,particularly for large problem sizes. 展开更多
关键词 Systems of nonlinear equation Order of convergence Higher-order method Extended Newton iteration Computational efficiency
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暨南大学刘逸课题组在IEEE S&P 2025发表成果
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作者 《信息网络安全》 北大核心 2025年第8期1326-1326,共1页
近日,暨南大学网络空间安全学院刘逸课题组在第46届安全与隐私研讨会IEEE S&P 2025上发表题为“Highly Efficient Actively Secure Two-Party Computation with One-Bit Advantage Bound”的研究论文。该成果由暨南大学网络空间安... 近日,暨南大学网络空间安全学院刘逸课题组在第46届安全与隐私研讨会IEEE S&P 2025上发表题为“Highly Efficient Actively Secure Two-Party Computation with One-Bit Advantage Bound”的研究论文。该成果由暨南大学网络空间安全学院教师刘逸、教授赖俊祚、教授杨安家、教授翁健与香港大学、南方科技大学等研究团队合作完成,暨南大学为第一单位与通信单位。安全两方计算(Secure Two-Party Computation)是密码学中重要的研究方向,可以让两个互不信任的参与者在保护各自输入隐私的情况下共同完成计算。 展开更多
关键词 Secure Two-Party Computation
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FedCLCC:A personalized federated learning algorithm for edge cloud collaboration based on contrastive learning and conditional computing
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作者 Kangning Yin Xinhui Ji +1 位作者 Yan Wang Zhiguo Wang 《Defence Technology(防务技术)》 2025年第1期80-93,共14页
Federated learning(FL)is a distributed machine learning paradigm for edge cloud computing.FL can facilitate data-driven decision-making in tactical scenarios,effectively addressing both data volume and infrastructure ... Federated learning(FL)is a distributed machine learning paradigm for edge cloud computing.FL can facilitate data-driven decision-making in tactical scenarios,effectively addressing both data volume and infrastructure challenges in edge environments.However,the diversity of clients in edge cloud computing presents significant challenges for FL.Personalized federated learning(pFL)received considerable attention in recent years.One example of pFL involves exploiting the global and local information in the local model.Current pFL algorithms experience limitations such as slow convergence speed,catastrophic forgetting,and poor performance in complex tasks,which still have significant shortcomings compared to the centralized learning.To achieve high pFL performance,we propose FedCLCC:Federated Contrastive Learning and Conditional Computing.The core of FedCLCC is the use of contrastive learning and conditional computing.Contrastive learning determines the feature representation similarity to adjust the local model.Conditional computing separates the global and local information and feeds it to their corresponding heads for global and local handling.Our comprehensive experiments demonstrate that FedCLCC outperforms other state-of-the-art FL algorithms. 展开更多
关键词 Federated learning Statistical heterogeneity Personalized model Conditional computing Contrastive learning
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Entire aerial-aquatic trajectory modeling and optimization for trans- medium vehicles
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作者 Teng Long Nianhui Ye +2 位作者 Baoshou Zhang Jingliang Sun Renhe Shi 《Defence Technology(防务技术)》 2025年第7期223-241,共19页
Trans-medium flight vehicles can combine high aerial maneuverability and underwater concealment ability,which have attracted much attention recently.As the most crucial procedure,the trajectory design generally determ... Trans-medium flight vehicles can combine high aerial maneuverability and underwater concealment ability,which have attracted much attention recently.As the most crucial procedure,the trajectory design generally determines the trans-medium flight vehicle performance.To quantitatively analyze the flight vehicle performance,an entire aerial-aquatic trajectory model is developed in this paper.Different from modeling a trajectory purely for the water entry process,the constructed entire trajectory model has integrated aerial,water entry,and underwater trajectories together,which can consider the influence of the connected trajectories.As for the aerial and underwater trajectories,explicit dynamic models are established to obtain the trajectory parameters.Due to the complicated fluid force during high-velocity water entry,a computational fluid dynamics model is investigated to analyze this phase.The compu-tational domain size is adaptively refined according to the final aerial trajectory state,where the redundant computational domain is removed.An entire trajectory optimization problem is then formulated to maximize the total flight range via tuning the joint states of different trajectories.Simultaneously,several constraints,i.e.,the max impact load,trajectory height,etc.,are involved in the optimization problem.Rather than directly optimizing by a heuristic algorithm,a multi-surrogate cooperative sampling-based optimization method is proposed to alleviate the computational complexity of the entire trajectory optimization problem.In this method,various surrogates coopera-tively generate infill sample points,thereby preventing the poor approximation.After optimization,the total flight range can be improved by 20%,while all the constraints are satisfied.The result demonstrates the effectiveness and practicability of the developed model and optimization framework. 展开更多
关键词 Water entry Trans-medium vehicle Computational fluid dynamics Trajectory optimization Pseudospectral method Surrogate
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Effects of horizontal splitter plates on the vortex-induced vibration and aerostatic characteristics of twin separated parallel decks for a rail-cum-road bridge
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作者 HE Xu-hui YANG Jia-feng +2 位作者 LIU Lu-lu ZOU Yun-feng HE Jing 《Journal of Central South University》 2025年第3期1024-1043,共20页
Installing the splitter plates is a passive aerodynamic solution for eliminating vortex-induced vibration (VIV). However, the influences of splitter plates on the VIV and aerostatic performances are more complicated d... Installing the splitter plates is a passive aerodynamic solution for eliminating vortex-induced vibration (VIV). However, the influences of splitter plates on the VIV and aerostatic performances are more complicated due to aerodynamic interference between highway and railway decks. To study the effects of splitter plates, wind tunnel experiments for measuring VIV and aerostatic forces of twin decks under two opposite flow directions were conducted, while the surrounding flow and wind pressure of static twin decks with and without splitter plates are numerically simulated. The results showed that the incoming flow direction affects the VIV response and aerostatic coefficients. The highway deck has poor vertical and torsional VIV, and the VIV region and amplitude are different under different directions. While the railway deck only has vertical VIV when located upstream. The splitter plates can impede the process of vortex generation, shedding and impinging at the gap between twin deck, and significantly reducing the surface fluctuating pressure coefficient, thus effectively suppressing the VIV of twin decks. While, the splitter plates hurt the upstream deck regarding static wind stability and have little effect on the downstream deck. The splitter plates of appropriate width are recommended to improve VIV performances in twin parallel bridges. 展开更多
关键词 splitter plates vortex-induced vibration(VIV) aerostatic characteristic wind tunnel test twin parallel decks the rail-cum-road bridges computational fluid dynamics
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Physical-layer secure hybrid task scheduling and resource management for fog computing IoT networks
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作者 ZHANG Shibo GAO Hongyuan +1 位作者 SU Yumeng SUN Rongchen 《Journal of Systems Engineering and Electronics》 2025年第5期1146-1160,共15页
Fog computing has emerged as an important technology which can improve the performance of computation-intensive and latency-critical communication networks.Nevertheless,the fog computing Internet-of-Things(IoT)systems... Fog computing has emerged as an important technology which can improve the performance of computation-intensive and latency-critical communication networks.Nevertheless,the fog computing Internet-of-Things(IoT)systems are susceptible to malicious eavesdropping attacks during the information transmission,and this issue has not been adequately addressed.In this paper,we propose a physical-layer secure fog computing IoT system model,which is able to improve the physical layer security of fog computing IoT networks against the malicious eavesdropping of multiple eavesdroppers.The secrecy rate of the proposed model is analyzed,and the quantum galaxy–based search algorithm(QGSA)is proposed to solve the hybrid task scheduling and resource management problem of the network.The computational complexity and convergence of the proposed algorithm are analyzed.Simulation results validate the efficiency of the proposed model and reveal the influence of various environmental parameters on fog computing IoT networks.Moreover,the simulation results demonstrate that the proposed hybrid task scheduling and resource management scheme can effectively enhance secrecy performance across different communication scenarios. 展开更多
关键词 fog computing Internet-of-Things(IoT) physical layer security hybrid task scheduling and resource management quantum galaxy-based search algorithm(QGSA)
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System Simulation Science and Simulation System Technology
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作者 Chuanyuan, Wen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1993年第4期2-11,共10页
This paper mainly discusses the following problems: the important meaning and special function of simulation system; the definition, contents and relationship of system and system simulation science; the definition an... This paper mainly discusses the following problems: the important meaning and special function of simulation system; the definition, contents and relationship of system and system simulation science; the definition and technology of simulation system and its equipments; and systematic description and exploration in relation to the developing trend of system simulation science and simulation system technology. 展开更多
关键词 Analog computers Control systems Digital computers Flight simulators Mathematical models Systems analysis Systems engineering Systems science Technology
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基于Petri网的服务组合故障诊断与处理 被引量:41
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作者 范贵生 虞慧群 +1 位作者 陈丽琼 刘冬梅 《软件学报》 EI CSCD 北大核心 2010年第2期231-247,共17页
通过分析服务组合的故障需求,给出服务组合故障处理的框架.该框架采用Petri网来解决服务组合的错误发现及其处理问题.重点讨论了可用服务失败、组件失败及网络故障的情况,并相应地给出了服务组合故障模型.在此基础上对故障处理模型进行... 通过分析服务组合的故障需求,给出服务组合故障处理的框架.该框架采用Petri网来解决服务组合的错误发现及其处理问题.重点讨论了可用服务失败、组件失败及网络故障的情况,并相应地给出了服务组合故障模型.在此基础上对故障处理模型进行分析,给出服务组合故障处理正确性准则,并证明了其正确性.最后,采用CTL(computational tree logic)描述相关性质并提出验证服务组合故障分析的实施算法.仿真结果表明,该方法在处理服务组合故障时具有一定的优越性. 展开更多
关键词 PETRI网 服务组合 故障处理 CTL(computational TREE logic) 可靠性
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基于工业CT测量数据的空心涡轮叶片三维壁厚分析 被引量:17
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作者 程云勇 张定华 +1 位作者 卜昆 张顺利 《机械强度》 CAS CSCD 北大核心 2009年第5期791-796,共6页
航空发动机空心涡轮叶片的壁厚是保证叶片强度的一个非常重要的参数,需要生产阶段进行全面的检测。以涡轮叶片的锥束CT(computed tomography)图象序列和叶片CAD(computer aided design)模型为基础,给出一种基于模板的空心涡轮叶片三维... 航空发动机空心涡轮叶片的壁厚是保证叶片强度的一个非常重要的参数,需要生产阶段进行全面的检测。以涡轮叶片的锥束CT(computed tomography)图象序列和叶片CAD(computer aided design)模型为基础,给出一种基于模板的空心涡轮叶片三维法向壁厚自动分析方法。使用亚像素级边缘检测算法,从叶片锥束CT图象序列提取叶片的高精度内、外表面点云数据,并进行空间栅格划分,以提高后续计算的效率。采用CAD驱动的模型配准方法实现叶片测量数据与CAD模型的可靠定位。依据叶片壁厚特征在叶片CAD模型上定义壁厚分析模板,通过壁厚分析模板与叶片点云数据的求交运算,得到对应区域的三维壁厚与壁厚偏差分布。使用一组仿真生成的叶片CT图象序列对三维壁厚计算精度进行验证。 展开更多
关键词 锥束CT(computed tomography)涡轮叶片 法向壁厚 模板
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内锥流量计流出系数预测方法研究 被引量:14
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作者 徐英 吴经纬 +1 位作者 杨会峰 张涛 《计算力学学报》 EI CAS CSCD 北大核心 2009年第5期727-733,共7页
采用标准k-ε模型、RNG(Renormalization Group)k-ε模型、Realizablek-ε模型和Reynolds应力方程模型RSM(Reynolds Stress Model)对100 mm口径6种结构的内锥流量计内流场进行了数值模拟。在等效直径比β值为0.65的三种结构内锥流量计... 采用标准k-ε模型、RNG(Renormalization Group)k-ε模型、Realizablek-ε模型和Reynolds应力方程模型RSM(Reynolds Stress Model)对100 mm口径6种结构的内锥流量计内流场进行了数值模拟。在等效直径比β值为0.65的三种结构内锥流量计流出系数的仿真计算中,四种湍流模型计算结果与物理实验结果误差的平均值分别为4.19%,2.84%,2.88%和-0.822%;对β值为0.85的情况,各模型计算误差的平均值分别为11.8%,9.62%,9.30%和4.76%。研究结果表明,RSM模型在6种结构内锥流量计流出系数的预测中,计算精度较高,表现出了较好的性能,优于三种k-ε涡粘模型,更适于内锥流量计流场数值模拟与流出系数的预测。 展开更多
关键词 内锥流量计 流出系数 CFD(Computational FLUID Dynamics) 湍流模型 涡粘模型 RSM 雷诺数
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结合CFD技术的跨音速动导数计算方法研究 被引量:15
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作者 史爱明 杨永年 叶正寅 《西北工业大学学报》 EI CAS CSCD 北大核心 2008年第1期11-14,共4页
在非结构化动态网格技术基础上,采用二阶精度的中心有限体积法和全隐式双时间推进方法进行非定常欧拉方程求解。通过建立动导数计算模型,发展结合CFD的飞行器跨音速动导数计算方法。通过三维跨音速非定常欧拉方程的求解,数值模拟了国外... 在非结构化动态网格技术基础上,采用二阶精度的中心有限体积法和全隐式双时间推进方法进行非定常欧拉方程求解。通过建立动导数计算模型,发展结合CFD的飞行器跨音速动导数计算方法。通过三维跨音速非定常欧拉方程的求解,数值模拟了国外动导数计算标模Finner导弹的跨音速非定常绕流问题,进而计算了Finner导弹的跨音速纵向组合动导数,计算结果和文献中的风洞实验结果吻合较好,体现了方法的正确性。 展开更多
关键词 跨音速动导数 Finner导弹 非结构化动态网格 CFD(computational FLUID dynamics)
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利用近似贝氏计算推论台湾海峡沿岸秋茄种群的拓殖路线 被引量:6
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作者 阮宇 吕佳 +1 位作者 李俊清 肖国生 《生态学报》 CAS CSCD 北大核心 2015年第13期4304-4313,共10页
由于地理关系,台湾海峡两岸的红树植物组成具有高度的相似性,都以耐寒性较强的秋茄为优势种。中国台湾(以下简称"台湾")与大陆仅一水之隔,因此台湾的秋茄种群来源最有可能来自东南沿海种群,然而台湾南、北红树植物种群的拓殖... 由于地理关系,台湾海峡两岸的红树植物组成具有高度的相似性,都以耐寒性较强的秋茄为优势种。中国台湾(以下简称"台湾")与大陆仅一水之隔,因此台湾的秋茄种群来源最有可能来自东南沿海种群,然而台湾南、北红树植物种群的拓殖路线以及与大陆东南沿海种群的遗传关系的研究至今仍未见报道。通过SSR分子标记,利用近似贝氏计算(Approximate Bayesian Computation)推测海峡两岸4个分布区域秋茄的起源及其拓殖路线。结果表明4个区域的种群出现明显分化,大陆东南北部种群与其他种群间分化程度最高。通过推测台湾北部种群起源可追溯到29000—48400a前,早于末次冰期时间,且台湾北部种群遗传结构与大陆东南南部种群最相近,推测它们可能共同起源于南方祖先。大陆东南沿海南北种群的溯祖时间约为15.1万年至25.2a年前,约为更新世中期末,则意味东南沿海南、北种群的遗传分化可能受到更新世后期气候变化与海侵海退的影响而出现隔离,或东南沿海南、北种群可能来自不同的起源。而台湾南部种群与台湾北部种群的相似性,表明台湾南部种群是由北部种群拓殖而来,近似贝氏计算亦支持这个假说。因而,可以推测海峡两岸秋茄的拓殖路线是从大陆东南南方种群随黑潮迁移至台湾北部,再从北部拓殖到台湾南部。利用近似贝氏计算推论台湾海峡两岸红树林种群起源及拓殖路线,为未来我国东南沿海红树林植物的生物地理研究提供参考。 展开更多
关键词 秋茄 遗传结构 近似贝氏计算(Approximate BAYESIAN Computation) 起源 拓殖路线 中国台湾
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基于CFD的船用柴油机缸体水套设计 被引量:23
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作者 张强 王志明 《内燃机学报》 EI CAS CSCD 北大核心 2005年第6期548-553,共6页
利用数值模拟对6170型船用柴油机的冷却水套进行了冷却性能研究,优化设计了缸体冷却水套。对原机缸体冷却水套内冷却水的流场分布、冷却水套内壁面换热系数、各缸冷却均匀性和压力损失进行了分析。计算结果表明:原机缸体水套上部存在冷... 利用数值模拟对6170型船用柴油机的冷却水套进行了冷却性能研究,优化设计了缸体冷却水套。对原机缸体冷却水套内冷却水的流场分布、冷却水套内壁面换热系数、各缸冷却均匀性和压力损失进行了分析。计算结果表明:原机缸体水套上部存在冷却强度不足、冷却均匀性差的缺陷,不能满足缸套冷却要求。通过计算提出了提高缸体上部冷却强度及改善冷却均匀性的优化设计方案,从而满足了气缸套的冷却需要,确保了发动机工作的可靠性。 展开更多
关键词 柴油机 数值模拟 CFD(Computational FLUID Dynamic)分析 冷却水套
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水平轴潮流能水轮机设计与数值模拟 被引量:16
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作者 盛其虎 赵东亚 张亮 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2014年第4期389-394,共6页
为提高潮流能利用效率,基于叶素-动量理论(BEM),给出了Wilson模型在水平轴潮流能水轮机设计上的应用。采用CFD技术计算对设计的水轮机进行水动力特性分析,计算其在不同叶尖速比下的功率特性。在此基础上,对叶片沿展长方向的功率分布和... 为提高潮流能利用效率,基于叶素-动量理论(BEM),给出了Wilson模型在水平轴潮流能水轮机设计上的应用。采用CFD技术计算对设计的水轮机进行水动力特性分析,计算其在不同叶尖速比下的功率特性。在此基础上,对叶片沿展长方向的功率分布和三维绕流特性进行分析,并采用二维计算方法预测对应三维工况下各截面处的流场特性。计算结果表明,水轮机的工作特性满足对功率和效率的要求,说明了设计方法的可靠性;同时绕流特性分析也显示了二维模拟的局限性,尤其在叶根、叶尖部位失真较大,这说明三维效应对水轮机输出功率和流场性能有着显著的影响。 展开更多
关键词 潮流能 水平轴水轮机 叶素-动量理论 计算流体力学 数值模拟 三维效应 blade element momentum( BEM) computational fluid dynamics ( CFD)
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基于HPCC和层次分析法的高性能计算系统评价模型 被引量:10
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作者 刘川意 汪东升 《软件学报》 EI CSCD 北大核心 2007年第4期1039-1046,共8页
HPCC(high performance computing challenge)基准是由DARPA的HPCS(high productivity computing system)项目所发布的评价高性能计算系统的测试基准程序,自推出至今,受到工业界和学术界的广泛关注.但是,HPCC仍有不尽如人意之处,主要表... HPCC(high performance computing challenge)基准是由DARPA的HPCS(high productivity computing system)项目所发布的评价高性能计算系统的测试基准程序,自推出至今,受到工业界和学术界的广泛关注.但是,HPCC仍有不尽如人意之处,主要表现在其测试结果是若干个指标项,需要测试者和决策者根据这些测试指标项进行分析和评估,缺少一个整体的、直观而统一的评价结果.提出一种基于HPCC和层次分析法的高性能计算系统评价模型——AHPCC(a high performance computer system evaluation model based on HPCC),当系统通过运行HPCC得到测试结果后,使用AHPCC模型对这些测试参数按系统应用目标建立层次结构图,并最终计算得到各系统关于特定应用目标的单一分数.以12个已测出HPCC性能参数的系统为例,使用AHPCC模型计算并分析了系统评价结果.实验结果表明,AHPCC模型提供了实际系统的统一而直观的评价指标,其评价结果符合高性能系统的设计和应用特点. 展开更多
关键词 HPCC(high PERFORMANCE COMPUTING challenge)基准 层次分析法 系统评价
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一种基于聚类的虚拟计算环境资源聚合方法 被引量:5
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作者 褚瑞 卢锡城 肖侬 《软件学报》 EI CSCD 北大核心 2007年第8期1858-1869,共12页
作为面向互联网资源共享的虚拟计算环境的实例,iVCE(Internet based virtual computing environment)for Memory致力于解决广域分布的内存资源的共享与综合利用问题.由于内存资源的特殊性,传统的资源管理方法很难适用.以iVCE for Memor... 作为面向互联网资源共享的虚拟计算环境的实例,iVCE(Internet based virtual computing environment)for Memory致力于解决广域分布的内存资源的共享与综合利用问题.由于内存资源的特殊性,传统的资源管理方法很难适用.以iVCE for Memory作为背景,提出一种基于聚类的虚拟计算环境资源聚合方法,有效降低了资源聚合的问题规模;借鉴物理学中的力场和势能理论,建立了实现资源聚合的基本模型和力场-势能模型以及相应的分布式算法;通过基于真实网络拓扑的模拟,对两种模型和算法分别进行了评估和验证. 展开更多
关键词 虚拟计算环境 iVCE(Internet based VIRTUAL COMPUTING environment)for MEMORY 资源聚合 聚类 力场-势能模型
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