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Definition,measuring methods and status of carbon information disclosure in Chinese enterprises
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作者 CHEN Hua WANG Hai-yan 《Ecological Economy》 2015年第4期393-400,共8页
From the perspective of carbon disclosure goal,the paper defined the detail types of contents about carbon information disclosure,then constructed the carbon information disclosure index,by using the indices to 2011 a... From the perspective of carbon disclosure goal,the paper defined the detail types of contents about carbon information disclosure,then constructed the carbon information disclosure index,by using the indices to 2011 annual report of A-share listed companies in Shanghai and Shenzhen Security Exchange,we found that Chinese enterprises' carbon disclosure scattered,industry structure quite different characteristics,quantity information and quality information asymmetry. 展开更多
关键词 CARBON information DISCLOSURE content definition measuring methods STATUS DESCRIPTION
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The Optimal Precursors for ENSO Events Depicted Using the Gradientdefinition-based Method in an Intermediate Coupled Model
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作者 Bin MU Juhui REN +3 位作者 Shijin YUAN Rong-Hua ZHANG Lei CHEN Chuan GAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第12期1381-1392,共12页
The predictability of El Ni-o-Southern Oscillation (ENSO) has been an important area of study for years. Searching for the optimal precursor (OPR) of ENSO occurrence is an effective way to understand its predictabilit... The predictability of El Ni-o-Southern Oscillation (ENSO) has been an important area of study for years. Searching for the optimal precursor (OPR) of ENSO occurrence is an effective way to understand its predictability. The CNOP (conditional nonlinear optimal perturbation), one of the most effective ways to depict the predictability of ENSO, is adopted to study the optimal sea surface temperature (SST) precursors (SST-OPRs) of ENSO in the IOCAS ICM (intermediate coupled model developed at the Institute of Oceanology, Chinese Academy of Sciences). To seek the SST-OPRs of ENSO in the ICM, non-ENSO events simulated by the ICM are chosen as the basic state. Then, the gradient-definition-based method (GD method) is employed to solve the CNOP for different initial months of the basic years to obtain the SSTOPRs. The experimental results show that the obtained SST-OPRs present a positive anomaly signal in the western-central equatorial Pacific, and obvious differences exist in the patterns between the different seasonal SST-OPRs along the equatorial western-central Pacific, showing seasonal dependence to some extent. Furthermore, the non-El Ni-o events can eventually evolve into El Ni-o events when the SST-OPRs are superimposed on the corresponding seasons;the peaks of the Ni-o3.4 index occur at the ends of the years, which is consistent with the evolution of the real El Ni-o. These results show that the GD method is an effective way to obtain SST-OPRs for ENSO events in the ICM. Moreover, the OPRs for ENSO depicted using the GD method provide useful information for finding the early signal of ENSO in the ICM. 展开更多
关键词 OPTIMAL precursor ENSO gradient-definition-based method conditional nonlinear OPTIMAL perturbation INTERMEDIATE coupled model
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A NOTE ON COMPARISON THEOREM OF TWO-STAGE ITERATIVE METHOD FOR HERMITIAN POSITIVE DEFINITE LINEAR SYSTEMS 被引量:1
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作者 王川龙 王艳萍 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2003年第1期59-65,共7页
We discuss two-stage iterative methods for the solution of linear systemAx = b, and give a new proof of the comparison theorems of two-stage iterative methodfor an Hermitian positive definite matrix. Meanwhile, we put... We discuss two-stage iterative methods for the solution of linear systemAx = b, and give a new proof of the comparison theorems of two-stage iterative methodfor an Hermitian positive definite matrix. Meanwhile, we put forward two new versionsof well known comparison theorem and apply them to some examples. 展开更多
关键词 Hermitian正定线性系统 HERMITIAN矩阵 正定矩阵 二阶迭代法 比较定理
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THE PARALLEL MULTISPLITTING METHOD FOR CONSISTENT SYMMETRIC POSITIVE(SEMI-)DEFINITE SYSTEMS
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作者 Liu Zhongyun (dept.of Math.,Shanghai Univrsity,Shanghai 200436,PRC)Yinyueli(Light Industry Higher Training School,Changsha 410015,PRC)Li Renfa(Dept.of Comput.Sci.,Hunan University,Changsha 410082,PRC) 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2000年第S1期120-121,共2页
Main resultsTheorem 1 Let A be an n×n symmetric positive semidefinite matrix and let
关键词 SEMI definitE SYSTEMS THE PARALLEL MULTISPLITTING method FOR CONSISTENT SYMMETRIC POSITIVE
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长持时地震动对建筑结构抗震影响的研究进展 被引量:1
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作者 王维 李爱群 王星星 《工程力学》 EI CSCD 北大核心 2024年第9期18-30,共13页
该文综述了长持时地震动作用下建筑结构抗震性能的研究进展。介绍了长持时地震动的定义和特性;梳理了长持时地震动作用下建筑结构数值模拟、试验研究和理论分析的研究进展;详细综述了长持时地震动作用下建筑结构的延性性能、耗能能力、... 该文综述了长持时地震动作用下建筑结构抗震性能的研究进展。介绍了长持时地震动的定义和特性;梳理了长持时地震动作用下建筑结构数值模拟、试验研究和理论分析的研究进展;详细综述了长持时地震动作用下建筑结构的延性性能、耗能能力、易损性和抗倒塌性能的研究进展。此外,介绍了考虑长持时地震作用影响的建筑结构抗震设计方法,梳理了国内外建筑结构抗震设计规范对长持时地震作用的考虑方法,并对长持时地震动作用下建筑结构抗震性能的研究进行了展望。建议关注长持时地震动作用下建筑结构的抗震性能,进一步研究长持时地震动的定义和特性,改进长持时地震动作用下建筑结构的数值模拟、理论分析和试验研究方法,深入探讨长持时地震动作用下各类建筑结构的地震响应、易损性和抗倒塌性能,为未来结构抗震设计及评估中考虑长持时地震作用的影响和规范修订提供参考。 展开更多
关键词 防灾减灾工程及防护工程 综述 长持时地震动 定义 建筑结构 抗震性能 设计方法
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数字文献的定义与要素:一种概念分析
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作者 马海群 廉龙颖 《图书馆理论与实践》 2024年第5期14-24,共11页
数字文献是数字时代文献研究的基础性要素。文章针对国内外关于数字文献概念存在的内涵模糊、表达不全面和容易混淆等问题对数字文献进行概念构建,首先提出数字文献的定义,其次识别出数字文献概念涵盖的核心要素,最后展望数字文献概念... 数字文献是数字时代文献研究的基础性要素。文章针对国内外关于数字文献概念存在的内涵模糊、表达不全面和容易混淆等问题对数字文献进行概念构建,首先提出数字文献的定义,其次识别出数字文献概念涵盖的核心要素,最后展望数字文献概念的发展趋势。研究通过明确数字文献的概念,为数字文献研究提供清晰的理论支撑,也为文献学领域概念构建提供一种方法论支持。 展开更多
关键词 数字文献 概念分析 罗格斯概念分析法 数字文献定义 核心要素
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MBSE在动车组转向架失稳检测系统架构设计中的应用
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作者 刘义鑫 刘潇潇 +2 位作者 王保民 车军 李肇星 《机械科学与技术》 CSCD 北大核心 2024年第9期1615-1623,共9页
针对传统的动车组转向架失稳检测系统研制过程中出现设计数据追溯性差、模型复用性低、难以保证设计信息一致性,以及缺乏系统整体设计理念等一系列问题,将基于模型的系统工程(Modelbased system engineering,MBSE)应用于动车组转向架失... 针对传统的动车组转向架失稳检测系统研制过程中出现设计数据追溯性差、模型复用性低、难以保证设计信息一致性,以及缺乏系统整体设计理念等一系列问题,将基于模型的系统工程(Modelbased system engineering,MBSE)应用于动车组转向架失稳检测系统的设计。在Arcadia建模方法的基础上,结合功能定义分析方法对动车组转向架失稳检测系统进行架构设计:通过运行分析、系统分析、逻辑架构分析和物理架构分析4个层次建立其失稳检测系统“黑盒”到“白盒”的架构模型;通过识别功能、表达功能和评估功能3个环节对功能进行定义分析,并借助状态机仿真方式验证最终架构的逻辑正确性。研究表明:在动车组转向架失稳检测系统架构设计过程中,采用基于模型的系统工程方法建立的模型具有可追溯性和可复用性,可以在设计早期对系统进行整体设计,降低决策风险,对动车组转向架的研发有着积极的推动作用。 展开更多
关键词 MBSE 动车组转向架 失稳检测系统 Arcadia 功能定义分析方法
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基于等效松弛与交替方向乘子法的岸电系统优化调度
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作者 何胜利 邓任任 +3 位作者 黄堃 任禹丞 杨子跃 张如通 《微型电脑应用》 2024年第6期65-69,共5页
船舶在不同系泊方式下岸电系统电气参数频繁变化,同时岸电能量优化时存在目标函数非光滑、约束条件非线性、非凸等问题,通过引入辅助变量实现目标函数非光滑项的等效松弛,利用半正定规划与交替方向乘子法实现船舶在不同接线方式下的最... 船舶在不同系泊方式下岸电系统电气参数频繁变化,同时岸电能量优化时存在目标函数非光滑、约束条件非线性、非凸等问题,通过引入辅助变量实现目标函数非光滑项的等效松弛,利用半正定规划与交替方向乘子法实现船舶在不同接线方式下的最优调度,满足安全性与经济性保障。算例仿真表明,所提方法针对船舶径向连接与多船并靠连接混合模态共存条件下均表现突出,对于异构岸电系统共存的实际应用场景具备较好的工程实用性。 展开更多
关键词 岸电系统 交替方向乘子法 半正定规划 等效松弛
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High-precision inverse potentials for neutron-proton scattering using piece-wise smooth Morse functions
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作者 Ayushi Awasthi Arushi Sharma +1 位作者 Ishwar Kant O.S.K.S.Sastri 《Chinese Physics C》 SCIE CAS CSCD 2024年第10期201-213,共13页
The aim of this study is to construct inverse potentials for various ℓ-channels of neutron-proton scattering using a piece-wise smooth Morse function as a reference.The phase equations for single-channel states and th... The aim of this study is to construct inverse potentials for various ℓ-channels of neutron-proton scattering using a piece-wise smooth Morse function as a reference.The phase equations for single-channel states and the coupled equations of multi-channel scattering are solved numerically using the 5^(th) order Runge-kutta method.We employ a piece-wise smooth reference potential comprising three Morse functions as the initial input.Leveraging a machine learning-based genetic algorithm,we optimize the model parameters to minimize the mean-squared error between simulated and anticipated phase shifts.Our approach yields inverse potentials for both single and multichannel scattering,achieving convergence to a mean-squared error≤10^(-3).The resulting scattering lengths"a_(0)"and effective ranges"r"for ^(3)S_(1) and ^(1)S_(0) states,expressed as[a_(0),r],are found to be[5.445(5.424),1.770(1.760)]and[–23.741(–23.749),2.63(2.81)],respectively;these values are in excellent agreement with experimental ones.Furthermore,the calculated total scattering cross-sections are highly consistent with their experimental counterparts,having a percentage error of less than 1%.This computational approach can be easily extended to obtain interaction potentials for charged particle scattering. 展开更多
关键词 inverse potentials neutron-proton scattering piece-wise smooth Morse function phase function method reference potential approach genetic algorithm
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考虑电源与负荷间存在非正定相关性的概率潮流计算方法研究
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作者 曹宏宇 梁言贺 +3 位作者 刘惠颖 王晓宇 殷鑫 陈月 《电测与仪表》 北大核心 2024年第7期109-115,共7页
随着电动汽车等新型电力系统负荷类型的出现,电源和负荷间的相关性日趋复杂,针对利用Cholesky分解完成概率潮流计算会受电力系统电源和电力系统负荷之间相关矩阵影响的问题,即随着相关矩阵维度的增加相关矩阵变为非正定,最终导致潮流计... 随着电动汽车等新型电力系统负荷类型的出现,电源和负荷间的相关性日趋复杂,针对利用Cholesky分解完成概率潮流计算会受电力系统电源和电力系统负荷之间相关矩阵影响的问题,即随着相关矩阵维度的增加相关矩阵变为非正定,最终导致潮流计算无法进行的问题。文章提出一种新颖的处理相关性矩阵非正定的半不变量法,将修正Barzilai-Borwein梯度法与Nataf变换相结合,解决变量间相关矩阵非正定问题,并在IEEE-33节点系统中分析新型电力系统各类电源和负荷相关性对计算结果的影响,验证文章所提方法准确性。 展开更多
关键词 相关性 非正定 概率潮流 电动汽车充电负荷 半不变量法
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基于物性结构理论的材料因子表述与配列研究——以《当代汉语学习词典》定义式释义为例
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作者 邵文辉 袁世旭 《辞书研究》 2024年第1期45-59,86,I0002,共17页
物性结构理论为词汇表征提供了基本范式,同时为名物词所用定义式释义方式“种差”的选用与配列提供了研究手段。文章对《当代汉语学习词典》定义式释义进行研究,以含材料因子的定义式释义为研究对象,发现在材料因子的表述模式上,《当代... 物性结构理论为词汇表征提供了基本范式,同时为名物词所用定义式释义方式“种差”的选用与配列提供了研究手段。文章对《当代汉语学习词典》定义式释义进行研究,以含材料因子的定义式释义为研究对象,发现在材料因子的表述模式上,《当代汉语学习词典》存在着多样化的特点;在材料因子与其他释义因子组合的配列框架上,《当代汉语学习词典》虽选用多种配列框架,但内部存在着较强的规律性。 展开更多
关键词 《当代汉语学习词典》 定义式释义 释义因子 材料因子 表述与配列
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基于视觉传达优化的低清晰度船舶图像复原研究
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作者 赵振华 《舰船科学技术》 北大核心 2024年第5期65-68,共4页
针对图像复原易出现复原图像颜色视觉特征失真问题,提出基于视觉传达优化的低清晰度船舶图像复原方法。该方法通过帧扫描方法,提取低清晰度船舶图像视觉传达信息的像素二维特征;使用基于最大后验概率的高分辨率船舶图像重组方法,将所提... 针对图像复原易出现复原图像颜色视觉特征失真问题,提出基于视觉传达优化的低清晰度船舶图像复原方法。该方法通过帧扫描方法,提取低清晰度船舶图像视觉传达信息的像素二维特征;使用基于最大后验概率的高分辨率船舶图像重组方法,将所提取低清晰度船舶图像视觉传达信息的像素二维特征,进行高分辨率特征重组,并引入基于视觉颜色模型的视觉传达效果优化复原方法,优化高分辨率特征重组后复原图像的颜色视觉传达效果。实验数据验证:该方法对低清晰度海域通行船舶监控图像复原处理后,图像视觉传达效果得到明显提升,且复原后船舶图像峰值信噪比、结构相似性指数接近1,图像特征失真小;复原后图像颜色特征显著性指数最大值达1.0,颜色特征细节显著性得以改善。 展开更多
关键词 视觉传达优化 低清晰度 船舶图像 复原方法 最大后验概率 视觉颜色模型
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辞格定义新论
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作者 郑荣馨 《贵州工程应用技术学院学报》 2024年第4期1-9,共9页
辞格定义,历来都有分歧意见。定义是认识世界的基础,只有通过清晰准确的定义,我们才能真正理解事物的本质。辞格定义的科学性对推进辞格研究的深入有重要的作用。通过梳理辞格的有代表性的不同定义,结合对辞格分歧意见的辨析给辞格下了... 辞格定义,历来都有分歧意见。定义是认识世界的基础,只有通过清晰准确的定义,我们才能真正理解事物的本质。辞格定义的科学性对推进辞格研究的深入有重要的作用。通过梳理辞格的有代表性的不同定义,结合对辞格分歧意见的辨析给辞格下了新的定义。 展开更多
关键词 辞格定义 语言表达效果 偏离 修辞方法
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汽车后视镜概论与设计
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作者 赵小群 陈敏 《汽车实用技术》 2024年第8期135-139,共5页
文章介绍了汽车后视镜的组成、材料、安装、性能和实验等基本特性和要求。针对后视镜在整车开发中的设计风险、装配风险,提出以阶段交付为设计方法,结合后视镜的造型、周边件的设计、安全法规、整车工程、内部布置、制造装配等相关因素... 文章介绍了汽车后视镜的组成、材料、安装、性能和实验等基本特性和要求。针对后视镜在整车开发中的设计风险、装配风险,提出以阶段交付为设计方法,结合后视镜的造型、周边件的设计、安全法规、整车工程、内部布置、制造装配等相关因素,定义后视镜各阶段的交付内容,以实现对汽车后视镜概论与设计的总体描述,为整车后视镜工程师优化设计和规避设计风险提供参考。 展开更多
关键词 后视镜组成 性能和实验 设计交付 匹配方式 断面定义
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Positive-Definite Sparse Precision Matrix Estimation 被引量:1
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作者 Lin Xia Xudong Huang +1 位作者 Guanpeng Wang Tao Wu 《Advances in Pure Mathematics》 2017年第1期21-30,共10页
The positive-definiteness and sparsity are the most important property of high-dimensional precision matrices. To better achieve those property, this paper uses a sparse lasso penalized D-trace loss under the positive... The positive-definiteness and sparsity are the most important property of high-dimensional precision matrices. To better achieve those property, this paper uses a sparse lasso penalized D-trace loss under the positive-definiteness constraint to estimate high-dimensional precision matrices. This paper derives an efficient accelerated gradient method to solve the challenging optimization problem and establish its converges rate as . The numerical simulations illustrated our method have competitive advantage than other methods. 展开更多
关键词 Positive-definiteness SPARSITY D-Trace Loss ACCELERATED Gradient method
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THEORY AND METHOD FOR WETLAND BOUNDARY DELINEATION
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作者 YIN Shu-bai LU Xian-guo 《Chinese Geographical Science》 SCIE CSCD 2006年第1期56-62,共7页
Based on the analysis of the subjectivity of wetland boundary criteria and their causes at present, this paper suggested that, under the condition that the mechanism of wetland formation process has not been understoo... Based on the analysis of the subjectivity of wetland boundary criteria and their causes at present, this paper suggested that, under the condition that the mechanism of wetland formation process has not been understood, "black box" method of System Theory can be used to delineate wetland boundaries scientifically. After analyzing the difference of system construction among aquatic habitats, wetlands and uplands, the lower limit of rooted plants was chosen as the lower boundary criterion of wetlands. Because soil diagnostic horizon is the result of the long-term interaction among all environments, and it is less responsive than vegetation to short-term change, soil diagnostic horizon was chosen as the indicator to delineate wetland upper boundary, which lies at the thinning-out point of soil diagnostic horizon. Case study indicated that it was feasible using the lower limit of rooted plants and the thinning-out point of soil diagnostic horizon as criteria to delineate the lower and upper boundaries of wetland. In the study area, the thinning-out line of albic horizon was coincident with the 55.74m contour line, the maximum horizon error was less than 1m, and the maximum vertical error less than 0.04m. The problem on wetland definition always arises on the boundaries. Having delineated wetland boundaries, wetlands can be defined as follows: wetlands are the transitional zones between uplands and deepwater habitats, they are a kind of azonal complex that are inundated or saturated by surface or ground water, with the lower boundary lying at the lower limit of rooted plants, and the upper boundary at the thinning-out line of upland soil diagnostic horizon. 展开更多
关键词 wetland boundary "black box" method soil diagnostic horizon thinning-out point (line) wetland definition
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About the Reliability of Particle in Cell Methods and the Notion of a“Local”Temperature of Ionized Species Around a Spacecraft in the Ionosphere
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作者 Roger Godard John D.de Boer 《Journal of Physical Science and Application》 2020年第2期1-9,共9页
The development of space science has generated important computer codes for the simulation of the interaction between complex space structures(artificial satellites,solar panels,etc.)and the surrounding plasma.The bas... The development of space science has generated important computer codes for the simulation of the interaction between complex space structures(artificial satellites,solar panels,etc.)and the surrounding plasma.The basic equation to be solved is the Poisson equation for the electric potential around a structure.Here,we try to study analytically the shadowing effect of a spacecraft on an electrode for the electron number density and the electron temperature.We suggest that the electron temperature should be taken as a variable and not as a parameter.However,its computation involves the knowledge of the histogram of the distribution of the frequencies of the electron velocities inside the computational cells.Also,we have illustrated the possibilities of artefacts due to the design and geometry of scientific instruments for the measurement of the electron number density and the electron temperature in the ionosphere.We suggest an optimal design for an electrode and its guard ring. 展开更多
关键词 Plasma physics particle-in-cell methods(PIC) electron number density definition of the electron temperature
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数字孪生体可信度评估过程及指标研究 被引量:6
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作者 杨帆 马萍 +1 位作者 李伟 杨明 《系统仿真学报》 CAS CSCD 北大核心 2023年第2期350-358,共9页
随着数字孪生技术应用领域的扩展,为满足数字孪生体可信度要求和推动数字孪生体可信度评估工作,对数字孪生体可信度评估过程和指标进行了研究。分析了数字孪生体的开发过程,给出了基于IDEF0(integrated computer aided manufacturing-de... 随着数字孪生技术应用领域的扩展,为满足数字孪生体可信度要求和推动数字孪生体可信度评估工作,对数字孪生体可信度评估过程和指标进行了研究。分析了数字孪生体的开发过程,给出了基于IDEF0(integrated computer aided manufacturing-definition method)的柔性多层级数字孪生体可信度评估过程模型构建方法。提出了过程—阶段—活动层(P-S-A)和活动—元素—特性层(A-E-F)两类指标体系,分别辅助解决缺陷回溯问题和复杂对象评估问题,并给出了指标体系范例。 展开更多
关键词 数字孪生 可信度评估 IDEF0 过程模型 指标体系
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Preconditioned Iterative Methods for Algebraic Systems from Multiplicative Half-Quadratic Regularization Image Restorations 被引量:1
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作者 Michael K.Ng 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2010年第4期461-474,共14页
Image restoration is often solved by minimizing an energy function consisting of a data-fidelity term and a regularization term.A regularized convex term can usually preserve the image edges well in the restored image... Image restoration is often solved by minimizing an energy function consisting of a data-fidelity term and a regularization term.A regularized convex term can usually preserve the image edges well in the restored image.In this paper,we consider a class of convex and edge-preserving regularization functions,i.e.,multiplicative half-quadratic regularizations,and we use the Newton method to solve the correspondingly reduced systems of nonlinear equations.At each Newton iterate,the preconditioned conjugate gradient method,incorporated with a constraint preconditioner,is employed to solve the structured Newton equation that has a symmetric positive definite coefficient matrix. The eigenvalue bounds of the preconditioned matrix are deliberately derived,which can be used to estimate the convergence speed of the preconditioned conjugate gradient method.We use experimental results to demonstrate that this new approach is efficient, and the effect of image restoration is reasonably well. 展开更多
关键词 Edge-preserving image restoration multiplicative half-quadratic regularization Newton method preconditioned conjugate gradient method constraint preconditioner eigenvalue bounds
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干旱传播研究进展与展望Ⅰ--干旱传播含义、特征、类型与研究方法 被引量:3
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作者 智协飞 田云涛 +1 位作者 陈昌春 张余庆 《南水北调与水利科技(中英文)》 CAS CSCD 北大核心 2023年第4期625-653,共29页
在回顾干旱传播概念和内涵的基础上,明确提出干旱传播全环节的详细定义,阐述干旱传播的累积、衰减、滞后及延长特征,并重点就累积性与滞后性提炼了有关进展。按干旱传播环节、干旱传播时空特征两种方法划分干旱传播的类型,从线性回归、... 在回顾干旱传播概念和内涵的基础上,明确提出干旱传播全环节的详细定义,阐述干旱传播的累积、衰减、滞后及延长特征,并重点就累积性与滞后性提炼了有关进展。按干旱传播环节、干旱传播时空特征两种方法划分干旱传播的类型,从线性回归、对数函数、小波分析、Copula函数、因果分析、贝叶斯网络和随机森林7个方面、从单一水文模型模拟和多个模型集合模拟两大方面,分别归纳统计方法、水文模拟方法在干旱传播研究领域的应用。 展开更多
关键词 干旱传播 定义 特征 类型 方法 进展
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