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线性过程的收敛速度
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作者 胡舒合 《高校应用数学学报(A辑)》 CSCD 北大核心 1996年第2期193-198,共6页
设X_t=sum from j=0 to ∞ c_jε_(t-j)是一个线性过程,当{ε_t}是一个局部广义高斯随机序列时,我们获得了X_t的重对数收敛速度。
关键词 对数速度 线性过程 收敛速度 随机过程
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负相协随机变量列尾和的重对数律
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作者 刘立新 《工程数学学报》 CSCD 北大核心 2006年第5期827-834,共8页
设{X_n,n≥1}为负相协随机变量序列,S=sum from n=1 to∞X_n收敛,本文讨论了部分和S_n=sum from k=1 to n-1 X_k→S的收敛速度,获得了关于尾和U_n=S-S_n的重对数律。
关键词 负相协随机变量 尾和 收敛速度:重对数
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一种高超声速滑翔再入在线轨迹规划算法 被引量:12
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作者 李俊 江振宇 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2020年第3期579-587,共9页
为了提高滑翔再入飞行器响应动态任务的能力并提高其制导系统的鲁棒性,建立了高超声速滑翔再入轨迹规划问题的一种在线求解算法。该算法以一列凸子问题来逼近原问题。通过选择以弧长为自变量并引入对数速度代替速度作为状态,使得动力学... 为了提高滑翔再入飞行器响应动态任务的能力并提高其制导系统的鲁棒性,建立了高超声速滑翔再入轨迹规划问题的一种在线求解算法。该算法以一列凸子问题来逼近原问题。通过选择以弧长为自变量并引入对数速度代替速度作为状态,使得动力学方程的非线性大为减弱,同时使动压和热流约束完全成为线性约束。通过使用类似于混合整数规划中割平面的思想处理禁飞区约束,尽可能避免了不必要的计算。通过直接以气动系数和大气密度的乘积作为控制量,构造伪线性控制模型,进一步减弱非线性。非凸约束被适当松弛,以保证子问题的可行性。为了避免过度松弛,利用离线给定的高度和速度上下边界估计对应的参数,以加速收敛。以X-33再入任务为例验证了所提算法的有效性。该算法可以以简单的常值函数为初值并在数次迭代后收敛。 展开更多
关键词 再入轨迹规划 对数速度 凸优化 最优控制 割平面法
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基于交通流理论的道路实际通行能力模型 被引量:5
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作者 郑松竺 徐雅琳 李梦思 《中国传媒大学学报(自然科学版)》 2014年第4期42-46,共5页
车道被占用会导致道路横断面通行能力在单位时间内降低,从而影响整个路段的交通状况,造成堵车。针对车道被占用问题,基于2013年全国大学生数学建模竞赛A题所提供的道路交通事故监控视频案例的人工观测数据,以对数关系的流量-速度模型为... 车道被占用会导致道路横断面通行能力在单位时间内降低,从而影响整个路段的交通状况,造成堵车。针对车道被占用问题,基于2013年全国大学生数学建模竞赛A题所提供的道路交通事故监控视频案例的人工观测数据,以对数关系的流量-速度模型为基础,结合交通工程学理论和通行能力修正系数,导出了道路实际通行能力的计算模型。同时根据交通流理论,建立了一个包含上游流量、事故所处横断面实际通行能力、事故持续时间和堵车排队长度的模型,根据其中任意三个量可求解另外一个量。经检验,模型结果和实际交通情况较吻合,且易于操作,具有一定的实际意义和应用价值。 展开更多
关键词 通行能力 对数流量-速度模型 修正系数 交通流
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物理海洋学与海洋气象学系
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《山东海洋学院学报》 1985年第C00期1-11,共11页
潮波空间问题的一种非线性模型,湍流速度分布对数律的一点修正,风暴潮的理论模化,大洋风生—热盐环流模型,f—平面上的宽陆架诱导阻尼波,超浅海风暴潮的数值模拟(Ⅰ)——零阶模型对渤海风潮的初步应用……
关键词 潮波空间 非线性模型 湍流 速度分布对数 风暴潮 海洋气象学
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Establishment of wear model and life prediction of drum of hot rolling coiler
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作者 章健 彭艳 +1 位作者 刘宏民 刘云飞 《Journal of Central South University》 SCIE EI CAS 2011年第6期1808-1812,共5页
For the drum of hot rolling coiler is prone to be easily destroyed, the type of MMU-5G abrasion tester was applied to revealing the friction and wear behavior. The morphology observation by scanning electron microscop... For the drum of hot rolling coiler is prone to be easily destroyed, the type of MMU-5G abrasion tester was applied to revealing the friction and wear behavior. The morphology observation by scanning electron microscope (SEM) demonstrates the wear mechanism of the drum, and the test data of the influence coefficient of the normal pressure, relative sliding speed and surface lubrication conditions acted on the linear rate of the wear could be obtained by the regression method. A calculation model, which considers the factors of the structure of the drum, coiling tension and coiling strip specifications, was established by the combination method to predict the wear life of the drum. Then the practical production data was applied into this model and the analysis result was in good accordance with that of actual production. 展开更多
关键词 DRUM wear mechanism combination method wear model wear life
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Strong Approximation Method and the(Functional)Law of Iterated Logarithm for GI/G/1 Queue 被引量:2
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作者 GUO Yongjiang HOU Xiyang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2017年第5期1097-1106,共10页
In this paper, a unified method based on the strong approximation(SA) of renewal process(RP) is developed for the law of the iterated logarithm(LIL) and the functional LIL(FLIL), which quantify the magnitude of the as... In this paper, a unified method based on the strong approximation(SA) of renewal process(RP) is developed for the law of the iterated logarithm(LIL) and the functional LIL(FLIL), which quantify the magnitude of the asymptotic rate of the increasing variability around the mean value of the RP in numerical and functional forms respectively. For the GI/G/1 queue, the method provides a complete analysis for both the LIL and the FLIL limits for four performance functions: The queue length, workload, busy time and idle time processes, covering three regimes divided by the traffic intensity. 展开更多
关键词 GI/G/1 queue renewal process (RP) strong approximation (SA) method the functional LIL (FLIL) the law of the iterated logarithm (LIL)
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Electrochemical behavior of [UO_2Cl_4]^(2-) in 1-ethyl-3-methylimidazolium based ionic liquids 被引量:6
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作者 OGURA Toshinari SASAKI Kotoe +2 位作者 TAKAO Koichiro ARAI Tsuyoshi IKEDA Yasuhisa 《Science China Chemistry》 SCIE EI CAS 2012年第9期1699-1704,共6页
In order to examine the chemical form of uranyl species in l-ethyl-3-methylimidazolium (EMI) based ionic liquids, UV-visible absorption spectra of solutions prepared by dissolving [EMI]2[UO2CI4] into a mixture of EM... In order to examine the chemical form of uranyl species in l-ethyl-3-methylimidazolium (EMI) based ionic liquids, UV-visible absorption spectra of solutions prepared by dissolving [EMI]2[UO2CI4] into a mixture of EMICI and EMIBF4 (50:50 tool%) were measured. As a result, it was confirmed that uranyl species in the mixture of EMICI and EMIBF4 existed as [UO2C14]2-. Cyclic voltammograms (CVs) of [UO2CI4]2- in the mixture were measured at 25 ~C using a Pt working electrode, a Pt wire counter electrode, and an Ag/Ag+ reference electrode (0.01 M AgNO3, 0.1 M tetrabutylammonium perchlorate in acetonitrile) in a glove box under an Ar atmosphere. Peaks corresponding to one redox couple were observed around -1.05 V (Epc) and -0.92 V (Epa) vs. ferrocene/ferrocenium ion (Fc/Fc+). The potential differences between two peaks (AEp) increased from 101 to 152 mV with an increase in the scan rate from 50 to 300 mV s-1, while the (Epc + Epa)/2 value was constant, -0.989 V vs. Fc/Fc+ regardless of the scan rate. Furthermore, the diffusion coefficient of [UO2C14]2 and the standard rate constant were es- timated to be 3.7× 10^-8 cm^2 s 1 and (2.7-2,8) × 10^-4 cm s-! at 25 ℃. By using the diffusion coefficient and the standard rate constant, the simulation of CVs was performed based on the reaction, [UO2C14]2- + e- = [UO2C14]3-. The simulated CVs were found to be consistent with the experimental ones. From these results, it is concluded that [UO2C14]2- in the mixture of EMIC1 and EMIBF4 is reduced to [UO2C14]3- quasi-reversibly at -0.989 V vs. Fc/Fc+. 展开更多
关键词 uranyl chloride ionic liquids ELECTROCHEMISTRY cyclic voltammetry
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Convergence Rate of the Asymmetric Deffuant-Weisbuch Dynamics 被引量:4
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作者 ZHANG Jiangbo CHEN Ge 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2015年第4期773-787,共15页
This paper considers the convergence rate of an asymmetric Deffuant-Weisbuch model.The model is composed by finite n interacting agents.In this model,agent i’s opinion is updated at each time,by first selecting one r... This paper considers the convergence rate of an asymmetric Deffuant-Weisbuch model.The model is composed by finite n interacting agents.In this model,agent i’s opinion is updated at each time,by first selecting one randomly from n agents,and then combining the selected agent j’s opinion if the distance between j’s opinion and i’s opinion is not larger than the confidence radiusε0.This yields the endogenously changing inter-agent topologies.Based on the previous result that all agents opinions will converge almost surely for any initial states,the authors prove that the expected potential function of the convergence rate is upper bounded by a negative exponential function of time t when opinions reach consensus finally and is upper bounded by a negative power function of time t when opinions converge to several different limits. 展开更多
关键词 Convergence rute Deffuant-Weisbuch model multi-agent systems opinion dynamics.
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The Thermal Character of the Underwater Heat Exhausting Source 被引量:2
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作者 Shengtao Chen,Huanying Liu and Yi Qi Science and Technology on Underwater Test and Control Laboratory,PO Box 67,Dalian,Liaoning 116013 《Journal of Thermal Science》 SCIE EI CAS CSCD 2010年第5期445-450,共6页
The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical s... The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera. 展开更多
关键词 heat exhausting hot wake thermal character underwater target
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