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Optimal state and branch sequence based parameter estimation of continuous hidden Markov model
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作者 俞璐 吴乐南 谢钧 《Journal of Southeast University(English Edition)》 EI CAS 2005年第2期136-140,共5页
A parameter estimation algorithm of the continuous hidden Markov model isintroduced and the rigorous proof of its convergence is also included. The algorithm uses theViterbi algorithm instead of K-means clustering use... A parameter estimation algorithm of the continuous hidden Markov model isintroduced and the rigorous proof of its convergence is also included. The algorithm uses theViterbi algorithm instead of K-means clustering used in the segmental K-means algorithm to determineoptimal state and branch sequences. Based on the optimal sequence, parameters are estimated withmaximum-likelihood as objective functions. Comparisons with the traditional Baum-Welch and segmentalK-means algorithms on various aspects, such as optimal objectives and fundamentals, are made. Allthree algorithms are applied to face recognition. Results indicate that the proposed algorithm canreduce training time with comparable recognition rate and it is least sensitive to the training set.So its average performance exceeds the other two. 展开更多
关键词 continuous hidden Markov model optimal state and branch sequence MAXIMUMLIKELIHOOD CONVERGENCE viterbi algorithm
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KSN heterozygosity is associated with continuous flowering of Rosa rugosa Purple branch 被引量:1
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作者 Mengjuan Bai Jinyi Liu +6 位作者 Chunguo Fan Yeqing Chen Hui Chen Jun Lu Jingjing Sun Guogui Ning Changquan Wang 《Horticulture Research》 SCIE 2021年第1期305-315,共11页
Rose(Rosa spp.)plants flower via two contrasting methods:once flowering(OF)and continuous flowering(CF).Purple branch is a rare continuously flowering variety of Rosa rugosa that is extensively cultivated in China.How... Rose(Rosa spp.)plants flower via two contrasting methods:once flowering(OF)and continuous flowering(CF).Purple branch is a rare continuously flowering variety of Rosa rugosa that is extensively cultivated in China.However,the genetic basis of its CF behavior is unknown.We demonstrated that Purple branch is heterozygous for the TFL1 homolog KSN.One KSN allele with a 9kb Copia insertion was found to be identical to that from continuously flowering Rosa chinensis Old blush.The other allele was found to be a functional wild-type allele.The overall expression of KSN was closely linked to the floral transition,and it was significantly repressed in continuously flowering Purple branch compared with OF Plena.The promoter region of the normal KSN allele was hypermethylated,and histone methylation at H3H4,H3K9,and H3K27 of the KSN gene locus was modified in continuously flowering Purple branch.Silencing of the DNA methyltransferase genes MET1 and CMT3 and the histone methyltransferase gene SUVR5 in Purple branch led to enhanced KSN expression,but silencing of the histone demethylase gene JMJ12 suppressed KSN expression.Therefore,the CF habit of Purple branch may be due to reduced expression of KSN caused by the halved dose and may be associated with epigenetic modifications together with retrotransposon insertions along the chromosome.Our study revealed a novel mechanism underlying the CF behavior of rose plants. 展开更多
关键词 EXPRESSION branch continuously
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MOMENTS OF CONTINUOUS-STATE BRANCHING PROCESSES IN LéVY RANDOM ENVIRONMENTS 被引量:1
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作者 Lina JI Xiangqi ZHENG 《Acta Mathematica Scientia》 SCIE CSCD 2019年第3期781-796,共16页
For continuous-state branching processes in Lévy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuo... For continuous-state branching processes in Lévy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuous function satisfying some standard conditions. 展开更多
关键词 branching processes continuous-state MOMENTS RANDOM environment stochastic EQUATIONS
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The Convergence of 1-Periodic Branched Continued Fraction of the Special Form in Parabolic Regions
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作者 Dmytro I. Bodnar Mariia M. Bubniak 《Journal of Mathematics and System Science》 2014年第4期269-274,共6页
Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple ... Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple power series. We consider 1-periodic branched continued fraction of the special form which is an analog fraction with not equivalent variables if the values of that variables are fixed. We establish an analog of the parabola theorem for that fraction and estimate truncation error bounds for that fractions at some restrictions. We also propose to use weight coefficients for obtaining different parabolic regions for the same fraction without any additional restriction for first element. 展开更多
关键词 continued fractions 1-periodic branched continued fraction of special form CONVERGENCE uniform convergence truncation error bounds.
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The Levels-Recursive Algorithm for Vector Valued Interpolants by Triple Branched Continued Fractions
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作者 Shuo Tang Xuhui Wang 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2006年第2期137-142,共6页
A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical ... A kind of triple branched continued fractions is defined by making use of Samel- son inverse and Thiele-type partial inverted di?erences [1]. In this paper, a levels-recursive algorithm is constructed and a numerical example is given. 展开更多
关键词 Levels-Recursive算法 向量估计 连分数 部分逆
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Block Based Bivariate Blending Rational Interpolation via Symmetric Branched Continued Fractions
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作者 Qianjin Zhao Jieqing Tan 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2007年第1期63-73,共11页
This paper constructs a new kind of block based bivariate blending rational interpolation via symmetric branched continued fractions. The construction process may be outlined as follows. The first step is to divide th... This paper constructs a new kind of block based bivariate blending rational interpolation via symmetric branched continued fractions. The construction process may be outlined as follows. The first step is to divide the original set of support points into some subsets (blocks). Then construct each block by using symmetric branched continued fraction. Finally assemble these blocks by Newton’s method to shape the whole interpolation scheme. Our new method offers many flexible bivariate blending rational interpolation schemes which include the classical bivariate Newton’s polynomial interpolation and symmetric branched continued fraction interpolation as its special cases. The block based bivariate blending rational interpolation is in fact a kind of tradeoff between the purely linear interpolation and the purely nonlinear interpolation. Finally, numerical examples are given to show the effectiveness of the proposed method. 展开更多
关键词 插值 函数构造论 二变量 非线性特征
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A branch-and-bound algorithm for discrete multi-factor portfolio optimization model 被引量:1
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作者 牛淑芬 王国欣 孙小玲 《Journal of Shanghai University(English Edition)》 CAS 2008年第1期26-30,共5页
In this paper, a new branch-and-bound algorithm based on the Lagrangian dual relaxation and continuous relaxation is proposed for discrete multi-factor portfolio selection model with roundlot restriction in financial ... In this paper, a new branch-and-bound algorithm based on the Lagrangian dual relaxation and continuous relaxation is proposed for discrete multi-factor portfolio selection model with roundlot restriction in financial optimization. This discrete portfolio model is of integer quadratic programming problems. The separable structure of the model is investigated by using Lagrangian relaxation and dual search. Computational results show that the algorithm is capable of solving real-world portfolio problems with data from US stock market and randomly generated test problems with up to 120 securities. 展开更多
关键词 portfolio optimization discrete multi-factor model Lagrangian relaxation and continuous relaxation branch-and-bound method.
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基于主线不停运的城轨支线独立运营改造方案
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作者 戴志仁 李岩龙 +2 位作者 王泽宇 杨学金 张维驿 《铁道工程学报》 EI CSCD 北大核心 2024年第2期93-99,共7页
研究目的:针对大型铁路枢纽接入已运营轨道交通线路引起的既有线改造问题,为满足铁路枢纽与轨道交通连接线(支线)施工期间主线正常运营不受影响,对改造涉及的运营组织与接轨方案进行系统研究,并对土建、轨道、接触网、环网与动照、信号... 研究目的:针对大型铁路枢纽接入已运营轨道交通线路引起的既有线改造问题,为满足铁路枢纽与轨道交通连接线(支线)施工期间主线正常运营不受影响,对改造涉及的运营组织与接轨方案进行系统研究,并对土建、轨道、接触网、环网与动照、信号、综合监控与通信系统等的改造及影响进行深入研究,在统筹考虑实施难度、投资与工期的基础上,提出实施风险最小、技术最合理的改造方案。研究结论:(1)既有高架车站与区间改造影响范围较小且相对可控,可以实现主线正常运营情况下新建独立运营支线工程;(2)为最大程度保障主线运营不受影响,在现有技术水平条件下,应尽量避免在运营天窗期进行各类信号光电缆的割接;(3)支线独立运营方案,应尽量采取措施将新建支线与主线相连、轨道相通,以利于车辆检修与维保,并增加运营的灵活性;(4)桥梁浇筑与平移施工临近既有线,实施阶段应进一步完善工艺衔接与交叉施工统筹,增加既有线安全保障;(5)本研究结论可为类似工程提供参考。 展开更多
关键词 运营线路 主线 支线 实施风险 简支梁 连续梁 信号 帮接扩建
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强信号全覆盖下反射式强度型传感器信号调制设计
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作者 赵转莉 《自动化与仪表》 2024年第7期96-100,共5页
反射式强度型传感器在强信号全覆盖环境下常常受到干扰和影响,导致传感器信号的质量下降甚至失真,给后续的信号处理和数据分析带来了困难。对此,提出强信号全覆盖下反射式强度型传感器信号调制方法。首先,判断强信号全覆盖环境下传感器... 反射式强度型传感器在强信号全覆盖环境下常常受到干扰和影响,导致传感器信号的质量下降甚至失真,给后续的信号处理和数据分析带来了困难。对此,提出强信号全覆盖下反射式强度型传感器信号调制方法。首先,判断强信号全覆盖环境下传感器信号的稀疏性,并根据环境的干扰因素建立信号的观测矩阵,通过优化算法计算出稀疏向量的估计值,使用稀疏向量的估计值对观测信号进行补偿,得到补偿后的信号;然后,应用正交锁相放大技术,将补偿后的信号与严格正交的两路参考信号相乘,提高信噪比,获得增强后的信号;最后,利用连续相位多支路调制方法,对增强后的传感器信号展开比特信息分离、二维信号映射与载波相位调制操作,完成信号调制。实验结果表明,所提方法可扩展性强、稳定性高且抗干扰能力强。 展开更多
关键词 反射式强度型传感器 信号调制 正交锁相放大 连续相位多支路调制
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Small value probabilities for continuous state branching processes with immigration 被引量:1
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作者 CHU WeiJuan LI WenBo V REN YanXia 《Science China Mathematics》 SCIE 2012年第11期2259-2271,共13页
We consider the small value probability of supercritical continuous state branching processes with immigration. From Pinsky (1972) it is known that under regularity condition on the branching mechanism and immigrati... We consider the small value probability of supercritical continuous state branching processes with immigration. From Pinsky (1972) it is known that under regularity condition on the branching mechanism and immigration mechanism, the normalized population size converges to a non-degenerate finite and positive limit PV as t tends to infinity. We provide sharp estimate on asymptotic behavior of P(W≤ε〈) as ε→ 0+ by studying the Laplace transform of W. Without immigration, we also give a simpler proof for the small value probability in the non-subordinator case via the prolific backbone decomposition. 展开更多
关键词 continuous state branching process small value probability IMMIGRATION
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Almost sure, L1-and L2-growth behavior of supercritical multi-type continuous state and continuous time branching processes with immigration 被引量:1
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作者 Mátyás Barczy Sandra Palau Gyula Pap 《Science China Mathematics》 SCIE CSCD 2020年第10期2089-2116,共28页
Under a first order moment condition on the immigration mechanism,we show that an appropriately scaled supercritical and irreducible multi-type continuous state and continuous time branching process with immigration(C... Under a first order moment condition on the immigration mechanism,we show that an appropriately scaled supercritical and irreducible multi-type continuous state and continuous time branching process with immigration(CBI process)converges almost surely.If an x log(x)moment condition on the branching mechanism does not hold,then the limit is zero.If this x log(x)moment condition holds,then we prove L1 convergence as well.The projection of the limit on any left non-Perron eigenvector of the branching mean matrix is vanishing.If,in addition,a suitable extra power moment condition on the branching mechanism holds,then we provide the correct scaling for the projection of a CBI process on certain left non-Perron eigenvectors of the branching mean matrix in order to have almost sure and L1 limit.Moreover,under a second order moment condition on the branching and immigration mechanisms,we prove L2 convergence of an appropriately scaled process and the above-mentioned projections as well.A representation of the limits is also provided under the same moment conditions. 展开更多
关键词 multi-type continuous state and continuous time branching processes with immigration almost sure L1-and L2-growth behaviour
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Stochastic Equations for Two-type Continuous-state Branching Processes with Immigration 被引量:2
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作者 Ru Gang MA 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2013年第2期287-294,共8页
A two-dimensional stochastic integral equation system with jumps is studied. We first prove its unique weak solution is a two-type continuous-state branching process with immigration. Then the comparison property of t... A two-dimensional stochastic integral equation system with jumps is studied. We first prove its unique weak solution is a two-type continuous-state branching process with immigration. Then the comparison property of the solution is established. These results imply the existence and uniqueness of the strong solution of the stochastic equation system. 展开更多
关键词 continuous-state branching process IMMIGRATION stochastic integral equation comparison property strong solution
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“连行诗”命名的合理性研究——以陈东东的《七十二名》(组诗)为中心
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作者 张佳怡 《石家庄学院学报》 CAS 2024年第5期133-139,共7页
不论是中国的古诗词还是自外国传入的现代诗,分行作为显性的外部特征,一直都是构成诗歌的重要条件与标准。陈东东提出“连行诗”的这一概念冲击了大众对于诗歌秩序的认知,将诗歌文体的定义重新聚焦于内容本身。在表现方式上,“连行诗”... 不论是中国的古诗词还是自外国传入的现代诗,分行作为显性的外部特征,一直都是构成诗歌的重要条件与标准。陈东东提出“连行诗”的这一概念冲击了大众对于诗歌秩序的认知,将诗歌文体的定义重新聚焦于内容本身。在表现方式上,“连行诗”纠正了诗歌鉴赏对于形式的过分依赖,打破了旧有的分行标准,给予诗歌新的表达自由;在审美层面,“连行诗”纠正了过分私我化的表达趋势,强调日常的主体思索与精神表达,推动了检视原则的变更;在文体本身的定义中,“连行诗”的命名引出了诗歌的独特性与情感内核,缓和了变更引发的焦虑。在各个层面的质疑之下,“连行诗”作为形式本身已具备了诗性的意义。 展开更多
关键词 陈东东 “连行诗” 《七十二名》 分行标准 审美原则 文体焦虑
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Stochastic Model of Dengue: Analysing the Probability of Extinction and LLN
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作者 Ragnimwendé Sawadogo Fourtoua Victorien Konané Wahabo Baguian 《Applied Mathematics》 2024年第9期594-613,共20页
In this article, we develop and analyze a continuous-time Markov chain (CTMC) model to study the resurgence of dengue. We also explore the large population asymptotic behavior of probabilistic model of dengue using th... In this article, we develop and analyze a continuous-time Markov chain (CTMC) model to study the resurgence of dengue. We also explore the large population asymptotic behavior of probabilistic model of dengue using the law of large numbers (LLN). Initially, we calculate and estimate the probabilities of dengue extinction and major outbreak occurrence using multi-type Galton-Watson branching processes. Subsequently, we apply the LLN to examine the convergence of the stochastic model towards the deterministic model. Finally, theoretical numerical simulations are conducted exploration to validate our findings. Under identical conditions, our numerical results demonstrate that dengue could vanish in the stochastic model while persisting in the deterministic model. The highlighting of the law of large numbers through numerical simulations indicates from what population size a deterministic model should be considered preferable. 展开更多
关键词 Dengue Fever continuous-Time Markov Chain Multitype branching Process Probability of Disease Extinction Law of Large Numbers
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Time to most recent common ancestor for stationary continuous state branching processes with immigration
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作者 Hongwei BI 《Frontiers of Mathematics in China》 SCIE CSCD 2014年第2期239-260,共22页
Motivated by sample path decomposition of the stationary continuous state branching process with immigration, a general population model is considered using the idea of immortal individual. We compute the joint distri... Motivated by sample path decomposition of the stationary continuous state branching process with immigration, a general population model is considered using the idea of immortal individual. We compute the joint distribution of the random variables: the time to the most recent common ancestor (MRCA), the size of the current population, and the size of the population just before MRCA. We obtain the bottleneck effect as well. The distribution of the number of the oldest families is also established. These generalize the results obtained by Y. T. Chen and J. F. Delmas. 展开更多
关键词 continuous state branching process with immigration (CBI- processes) most recent common ancestor (MRCA) measured rooted real tree decomposition
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滇西北横断山脉一次持续强降水过程特征及成因分析
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作者 肖金宜 迪爱松 《山地气象学报》 2024年第1期87-94,共8页
【目的】分析滇西北横断山脉2020年5月24—27日持续性强降水天气过程特征和成因。【方法】利用ERA5再分析资料和怒江州气象观测站雨量数据,基于HYSPLIT模式及天气学诊断分析。【结果】(1)中高纬环流的调整使南支槽稳定在青藏高原南部,... 【目的】分析滇西北横断山脉2020年5月24—27日持续性强降水天气过程特征和成因。【方法】利用ERA5再分析资料和怒江州气象观测站雨量数据,基于HYSPLIT模式及天气学诊断分析。【结果】(1)中高纬环流的调整使南支槽稳定在青藏高原南部,上游风速增大使中高层形成西风急流,低层西南气流辐合,93~98°E、26~28°E区域维持>20 m·s^(-1)的纬向风且扩大东移;(2)贡山站过程累积雨量历史排行第二,暴雨持续日数达历年最高,具有一定的极端性。最大小时雨量9.9 mm,长时间降水的维持是引起此次过程的重要条件;(3)过程期间大气低层强辐合、中高层强辐散,抽吸作用明显,99°E区域低层强幅合中层强辐散中心与强降水落区相对应,中高层上升气流加强时期与降水集中时段对应较好,物理量的变化对降水趋势变化有指示意义;(4)低层水汽辐合强且向中高层输送,大于90%的相对湿度伸展至高层。水汽主要来源于孟加拉湾及阿拉伯海,部分水汽来自喇叭口地形作用及天气系统。【结论】加深对此类天气过程的了解和认识,为开展预报预警服务提供参考。 展开更多
关键词 持续性强降水 南支槽 西风急流 水汽来源
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树杈形桥墩景观人行桥设计与结构分析
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作者 郭相利 邓小伟 《上海公路》 2024年第4期85-88,131,M0005,M0006,共7页
随着我国经济水平的进步和人民生活质量的提高,景观人行桥的建设也日益增多。现介绍了一座采用树杈形桥墩的连续刚构景观人行桥的总体设计思路和结构设计要点,并进行了详细的结构分析计算。结果表明,采用树杈形桥墩的连续刚构人行桥的... 随着我国经济水平的进步和人民生活质量的提高,景观人行桥的建设也日益增多。现介绍了一座采用树杈形桥墩的连续刚构景观人行桥的总体设计思路和结构设计要点,并进行了详细的结构分析计算。结果表明,采用树杈形桥墩的连续刚构人行桥的结构刚度和竖向基频大,可满足规范对自振频率、刚度和强度的要求。该桥造型优美,受力合理,可为今后类似的景观桥设计提供参考。 展开更多
关键词 树杈形桥墩 连续刚构 景观人行桥 竖向基频
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考虑级联故障的电力系统脆弱性评估 被引量:19
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作者 周彦衡 吴俊勇 +3 位作者 张广韬 苗青 屈博 胡艳梅 《电网技术》 EI CSCD 北大核心 2013年第2期444-449,共6页
电力系统的大停电事故,多由级联故障而并非单一故障引起。为此,基于支路故障组合模型,通过对母线电压和支路功率稳定裕度的计算得出相应指标,对当前系统在N 1和N 2故障下进行风险评估,以为支路故障状态下的电力系统应对策略的制定提供... 电力系统的大停电事故,多由级联故障而并非单一故障引起。为此,基于支路故障组合模型,通过对母线电压和支路功率稳定裕度的计算得出相应指标,对当前系统在N 1和N 2故障下进行风险评估,以为支路故障状态下的电力系统应对策略的制定提供参考。算例结果验证了所提指标的有效性。 展开更多
关键词 级联故障 支路故障组合 连续潮流法 概率风险性 脆弱性评估
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一种用于预防支路型失稳故障的灵敏度方法 被引量:25
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作者 赵晋泉 江晓东 张伯明 《中国电机工程学报》 EI CSCD 北大核心 2004年第12期69-73,共5页
提出了一种新的用于评估支路型失稳故障严重程度的指标,并提出了一种可用于预防支路型失稳故障的灵敏度方法。严重的支路故障会造成电力系统立即失去静态稳定性。这些失稳的支路型故障都有一个对应于支路参数空间的虚拟的静态稳定临界... 提出了一种新的用于评估支路型失稳故障严重程度的指标,并提出了一种可用于预防支路型失稳故障的灵敏度方法。严重的支路故障会造成电力系统立即失去静态稳定性。这些失稳的支路型故障都有一个对应于支路参数空间的虚拟的静态稳定临界点。本文提出了基于这一稳定临界点的灵敏度分析方法,并将之应用于对支路型失稳故障的预防控制,取得了与负荷参数空间中稳定临界点处灵敏度:疗法同样的控制效果。文中通过一个600节点的实际系统算例说明本文所提方法的有效性。 展开更多
关键词 参数空间 临界点 失稳 算例 灵敏度分析 对应 节点 电力系统 静态稳定 故障
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2009-2013年中国西南地区连续干旱的成因分析 被引量:39
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作者 胡学平 王式功 +1 位作者 许平平 尚可政 《气象》 CSCD 北大核心 2014年第10期1216-1229,共14页
2009年以来,中国西南地区连续4年秋、冬、春季出现严重干旱,持续时间长、影响范围大、干旱程度重,给旱区农林业生产和人民生活带来严重影响,造成巨大的经济损失。本文利用多种资料从大尺度大气环流、水汽输送、太平洋及印度洋海温、平... 2009年以来,中国西南地区连续4年秋、冬、春季出现严重干旱,持续时间长、影响范围大、干旱程度重,给旱区农林业生产和人民生活带来严重影响,造成巨大的经济损失。本文利用多种资料从大尺度大气环流、水汽输送、太平洋及印度洋海温、平流层极涡等方面分析了此次连续干旱的原因。结果表明:南支槽强度偏弱、孟加拉湾水汽输送偏少以及弱极涡背景下,异常波活动造成的AO负异常引起的冷空气路径偏东是这4年持续干旱的共同特点。热带海表温度的异常变化对西南地区干旱的影响也不容忽视,主要表现在对孟加拉湾和南海水汽输送的阻碍上。La Nina事件中,热带印度洋冬、春季海表温度的异常变化对干旱影响更为突出。冬、春季平流层和对流层的动力耦合作用结果使得AO位相发生变化,其中异常负位相的强度及持续时间对这4年西南地区秋、冬、春连旱的影响显著。 展开更多
关键词 连续干旱 南支槽 水汽输送 热带海表温度 极涡
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