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Geochemical characteristics and genetic model of dolomite reservoirs in the eastern margin of the Pre-Caspian Basin 被引量:13
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作者 Wang Shuqin Zhao Lun +2 位作者 Cheng Xubin Fan Zifei He Ling 《Petroleum Science》 SCIE CAS CSCD 2012年第2期161-169,共9页
The widespread Carboniferous KT-I dolomite in the eastern margin of the Pre-Caspian Basin is an important hydrocarbon reservoir. The dolomite lithology is dominated by crystalline dolomite. The δ18O values range from... The widespread Carboniferous KT-I dolomite in the eastern margin of the Pre-Caspian Basin is an important hydrocarbon reservoir. The dolomite lithology is dominated by crystalline dolomite. The δ18O values range from -6.71‰ to 2.45‰, and average 0.063‰, obviously larger than -2.5‰, indicating low-temperature dolomite of evaporation origin. Stable strontium isotope ratios (87Sr/86Sr) range from 0.70829 to 0.70875 and average 0.708365, very consistent with 87Sr/86Sr ratios in Carboniferous seawater. Chemical analysis of Ca and Mg elements shows that the dolomite has 9.1 mole% excess Ca or even higher before stabilization. The degree of order of dolomite is medium–slightly poor, varying in a range of 0.336-0.504 and averaging 0.417. It suggests that the dolomite formed under near-surface conditions. There are two models for the origin of the Carboniferous KT-I dolomite reservoir. These are 1) the evaporation concentration – weathering crust model and 2) the shoal facies – seepage reflux model. The former is mainly developed in restricted platforms – evaporate platforms of restricted marine deposition environments with a representation of dolomite associated with gypsum and mudstone. The latter mainly formed in platform edge shoals and intra-platform shoals and is controlled by dolomitization due to high salinity sea water influx from adjacent restricted sea or evaporate platform. 展开更多
关键词 ISOTOPE DOLOMITE CARBONIFEROUS genetic model eastern margin of Pre-Caspian Basin
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Patterns and Dynamics of Rifting on Passive Continental Margin from Shelf to Slope of the Northern South China Sea:Evidence from 3D Analogue Modeling 被引量:14
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作者 孙珍 周蒂 +4 位作者 吴世敏 钟志洪 Myra Keep 姜建群 樊浩 《Journal of China University of Geosciences》 SCIE CSCD 2009年第1期136-146,共11页
Affected by thermal perturbation due to mantle uprising, the rheological structure of the lithosphere could be modified, which could lead to different rifting patterns from shelf to slope in a passive continental marg... Affected by thermal perturbation due to mantle uprising, the rheological structure of the lithosphere could be modified, which could lead to different rifting patterns from shelf to slope in a passive continental margin. From the observed deformation style on the northern South China Sea and analogue modeling experiments, we find that the rift zone located on the shelf is characterized by half grabens or simple grabens controlled mainly by long faults with large vertical offset, supposed to be formed with normal lithosphere extension. On the slope, where the lithosphere is very hot due to mantle upweUing and heating, composite grabens composed of symmetric grabens developed. The boundary and inner faults are all short with small vertical offset. Between the zones with very hot and normal lithosphere, composite half grabens composed of half grabens or asymmetric grabens formed, whose boundary faults are long with large vertical offset, while the inner faults are relatively short. Along with the thickness decrease of the brittle upper crust due to high temperature, the deformation becomes more sensitive to the shape of a pre-existing weakness zone and shows orientation variation along strike. When there was a bend in the pre-existing weakness zone, and the basal plate was pulled by a clockwise rotating stress, the strongest deformation always occurs along the middle segment and at the transition area from the middle to the eastern segments, which contributes to a hotter lithosphere in the middle segment, where the Baiyun (白云) sag formed. 展开更多
关键词 passive continental margin rifting pattern 3D analogue modeling South China Sea.
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Zero Truncated Bivariate Poisson Model: Marginal-Conditional Modeling Approach with an Application to Traffic Accident Data
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作者 Rafiqul I. Chowdhury M. Ataharul Islam 《Applied Mathematics》 2016年第14期1589-1598,共11页
A new covariate dependent zero-truncated bivariate Poisson model is proposed in this paper employing generalized linear model. A marginal-conditional approach is used to show the bivariate model. The proposed model wi... A new covariate dependent zero-truncated bivariate Poisson model is proposed in this paper employing generalized linear model. A marginal-conditional approach is used to show the bivariate model. The proposed model with estimation procedure and tests for goodness-of-fit and under (or over) dispersion are shown and applied to road safety data. Two correlated outcome variables considered in this study are number of cars involved in an accident and number of casualties for given number of cars. 展开更多
关键词 Bivariate Poisson Conditional model Generalized Linear model marginal model Road Safety Data Zero-Truncated
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Causal inference with marginal structural modeling for longitudinal data in laparoscopic surgery: A technical note
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作者 Zhongheng Zhang Peng Jin +7 位作者 Menglin Feng Jie Yang Jiajie Huang Lin Chen Ping Xu Jian Sun Caibao Hu Yucai Hong 《Laparoscopic, Endoscopic and Robotic Surgery》 2022年第4期146-152,共7页
Causal inference prevails in the field of laparoscopic surgery.Once the causality between an intervention and outcome is established,the intervention can be applied to a target population to improve clinical outcomes.... Causal inference prevails in the field of laparoscopic surgery.Once the causality between an intervention and outcome is established,the intervention can be applied to a target population to improve clinical outcomes.In many clinical scenarios,interventions are applied longitudinally in response to patients’conditions.Such longitudinal data comprise static variables,such as age,gender,and comorbidities;and dynamic variables,such as the treatment regime,laboratory variables,and vital signs.Some dynamic variables can act as both the confounder and mediator for the effect of an intervention on the outcome;in such cases,simple adjustment with a conventional regression model will bias the effect sizes.To address this,numerous statistical methods are being developed for causal inference;these include,but are not limited to,the structural marginal Cox regression model,dynamic treatment regime,and Cox regression model with time-varying covariates.This technical note provides a gentle introduction to such models and illustrates their use with an example in the field of laparoscopic surgery. 展开更多
关键词 Causal inference Laparoscopic surgery Machine learning marginal structural modeling
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Marginalized cubature Kalman filtering algorithm based on linear/nonlinear mixed-Gaussian model
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作者 Hu Yumei Hu Zhentao Jin Yong 《High Technology Letters》 EI CAS 2018年第4期362-368,共7页
Aiming at improving the estimation accuracy and real-time of nonlinear system with linear Gaussian sub-structure,a novel marginalized cubature Kalman filter is proposed in Bayesian estimation framework. Firstly,the ma... Aiming at improving the estimation accuracy and real-time of nonlinear system with linear Gaussian sub-structure,a novel marginalized cubature Kalman filter is proposed in Bayesian estimation framework. Firstly,the marginalized technique is adopted to model the target system dynamics with nonlinear state and linear state separately,and the two parts are estimated by cubature Kalman filter and standard Kalman filter respectively. Therefore,the linear part avoids the generation and propagation process of cubature points. Accordingly,the computational complexity is reduced.Meanwhile,the accuracy of state estimation is improved by taking the difference of nonlinear state estimation as the measurement of linear state. Furthermore,the computational complexity of marginalized cubature Kalman filter is discussed by calculating the number of floating-point operation. Finally,simulation experiments and analysis show that the proposed algorithm can improve the performance of filtering precision and real-time effectively in target tracking system. 展开更多
关键词 state estimation marginalized modeling mixed-Gaussian model CUBATURE KALMAN FILTER
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Numerical modeling of the development of southeastern Red Sea continental margin
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作者 Sunil Kumar Dwivedi Daigoro Hayashi 《Earthquake Science》 CSCD 2009年第3期239-249,共11页
The Red Sea continental margin (RSCM) corresponds to a wide hinge zone between Red Sea and Arabian plate. This margin has been studied through geological and geophysical observations primarily in regard to the evolu... The Red Sea continental margin (RSCM) corresponds to a wide hinge zone between Red Sea and Arabian plate. This margin has been studied through geological and geophysical observations primarily in regard to the evolution of Red Sea rift. This margin is characterized by occurrence of thin sediments, significant onshore uplift, tectonic subsidence of the offshore sedimentary basin, active faulting and seismicity. Studies indicate that sedimentary sequences of the margin are deformed by faults and folds resulting from at least two phases of extension and a phase of uplift. During the two phases of extension due to regional plate stress the sequence was cut by set of extensional faults. While during the phase of uplift the sequence was deformed by folding and faulting. The present paper aims to clear the structural development of RSCM during these tectonic episodes, taken as particular tectonic event, by two-dimensional finite element modeling on plane strain condition. Elastic theology is assumed for the oceanic, continental and transitional crust along with syntectonic deposits. Stress field, shear stress and fault distribution suggests that mantle plume weakened the crust following rifting due to regional stress and developed the margin. These results are well consistent with those from present seismicity, active faulting and neotectonic studies. 展开更多
关键词 Red Sea rift continental margin numerical modeling SEISMICITY NEOTECTONICS
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Stratigraphic Architecture and Computer Modelling of Carbonate Platform Margin,Late Ordovician Lianglitage Formation,Central Tarim Basin 被引量:2
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作者 李浩 林畅松 +3 位作者 张燕梅 张荣茜 芮志峰 黄理力 《Journal of Earth Science》 SCIE CAS CSCD 2012年第4期627-638,共12页
According to the different geometries and reflected characteristics in the seismic sections, the carbonate platform margin of the northern slope can be summarized as three basic depositional architectures in the Late ... According to the different geometries and reflected characteristics in the seismic sections, the carbonate platform margin of the northern slope can be summarized as three basic depositional architectures in the Late Ordovician Lianglitage (良里塔格) Formation of the Tazhong (塔中) uplift. The type one mainly located in the west of the carbonate platform margin, and it showed obvious imbricate progradation from the interior to the margin of the platform. The type two was in the middle of the carbonate platform margin, which showed retrogradational stacking pattern in the same transgres- sive systems tract period, and the slope strata of the platform margin showed progradational sequence in the highstand systems tract period. The type three located in the east of the carbonate platform margin, and it showed the parallel aggradational architecture. The crossing well section along the northern slope of the Tazhong carbonate platform showed that the depositional thickness became thinner from the east to the west. The thickest belt located in the east of the platform margin, and became thinner rapidly towards the basin and the platform interior. These indicated that the paleogeomorphology ofthe Tazhong uplift was probably high in the west and low in the east during the period of the Late Ordovician Lianglitage Formation. According to the interpretation of seismic profiles and the computer modelling result, the depositional architectures of sequence O31-2 showed aggradation, retrogradation and progradation from the east to the west of the carbonate platform margin during the transgression period. This meant that the accommodation became smaller gradually from the east to the west along the northern carbonate platform margin of the Tazhong uplift.The difference of the accommodation was probably caused by the difference of tectonic subsidence. Also, computer-aided modelling can be used to deeply understand the importance of various control parameters on the carbonate platform depositional architectures and processes. 展开更多
关键词 carbonate platform margin depositional architecture tectonic subsidence accommo-dation modelling.
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Modeling Water Quality Impacts of Growing Corn, Switchgrass, and <i>Miscanthus</i>on Marginal Soils 被引量:1
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作者 Mark A. Thomas Laurent M. Ahiablame +1 位作者 Bernard A. Engel Indrajeet Chaubey 《Journal of Water Resource and Protection》 2014年第14期1352-1368,共17页
The goal of the study was to model water quality impacts of growing perennial grasses on marginal soils. The GLEAMS-NAPRA and RUSLE models were used to simulate long-term surface runoff, percolation, erosion, total ph... The goal of the study was to model water quality impacts of growing perennial grasses on marginal soils. The GLEAMS-NAPRA and RUSLE models were used to simulate long-term surface runoff, percolation, erosion, total phosphorus (TP), and nitrate (NO3-N) losses associated with the production of corn-based bioenergy systems (i.e. conventional tillage corn and corn grain plus stover removal), switchgrass and Miscanthus on three marginal quality soils and one good quality soil in Indiana. Simulations showed that switchgrass and Miscanthus had no effect on annual runoff, but decreased percolation by at least 17%. Results also suggested a potential for reduction in erosion for Miscanthus across the soil types examined when compared to corn-based bioenergy production. The production of switchgrass and Miscanthus did not have significant effects on the simulated TP and NO3-N losses in runoff compared to corn production systems. Nitrates leached from fertilized Miscanthus production were approximately 90% lower than NO3-N leached from the production of fertilized switchgrass and corn systems. Additional studies are needed to better understand the hydrology, erosion and nutrient responses of Miscanthus and switchgrass production to meet bioenergy demands. 展开更多
关键词 Water Quality modelING Perennial Grass Runoff Biofuels marginAL Lands GLEAMS-NAPRA
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Marginal Conceptual Predictive Statistic for Mixed Model Selection
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作者 Cheng Wenren Junfeng Shang Juming Pan 《Open Journal of Statistics》 2016年第2期239-253,共15页
We focus on the development of model selection criteria in linear mixed models. In particular, we propose the model selection criteria following the Mallows’ Conceptual Predictive Statistic (Cp) [1] [2] in linear mix... We focus on the development of model selection criteria in linear mixed models. In particular, we propose the model selection criteria following the Mallows’ Conceptual Predictive Statistic (Cp) [1] [2] in linear mixed models. When correlation exists between the observations in data, the normal Gauss discrepancy in univariate case is not appropriate to measure the distance between the true model and a candidate model. Instead, we define a marginal Gauss discrepancy which takes the correlation into account in the mixed models. The model selection criterion, marginal Cp, called MCp, serves as an asymptotically unbiased estimator of the expected marginal Gauss discrepancy. An improvement of MCp, called IMCp, is then derived and proved to be a more accurate estimator of the expected marginal Gauss discrepancy than MCp. The performance of the proposed criteria is investigated in a simulation study. The simulation results show that in small samples, the proposed criteria outperform the Akaike Information Criteria (AIC) [3] [4] and Bayesian Information Criterion (BIC) [5] in selecting the correct model;in large samples, their performance is competitive. Further, the proposed criteria perform significantly better for highly correlated response data than for weakly correlated data. 展开更多
关键词 Mixed model Selection marginal Cp Improved marginal Cp marginal Gauss Discrepancy Linear Mixed model
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Gravity Modeling for the Rifted Crust at the Arabian Shield Margin – Further Insight into Red Sea Spreading
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作者 Saad Mogren Manoj Mukhopadhyay 《Open Journal of Geology》 2013年第2期28-33,共6页
A large variation in elevation and gravity anomaly prevails from the Red Sea coast to the interior of the Arabian Shield (AS) across the Asir Igneous Province (AIP);The Asir Mountain (AM) is developed on AIP. Here the... A large variation in elevation and gravity anomaly prevails from the Red Sea coast to the interior of the Arabian Shield (AS) across the Asir Igneous Province (AIP);The Asir Mountain (AM) is developed on AIP. Here the elevation varies from 45 - 2700 m, corresponding changes in F.A. are from –30 to + 220 mgal and B.A. from +22 to –175 mgal. Regression relationships between elevation and gravity anomalies demonstrate significant changes in trend at about 400 m threshold of elevation across the pediment west of AM, at about 45 km inland of the shoreline, flanking the Hizaz-Asir Escarpment (HAE). Gravity anomaly variation along a traverse taken across HAE and AIP is interpreted here in terms of anomalous masses in crust as well as due to deeper crustal configuration. 2D gravity interpretation is, in part, constrained by surface geology, available geologic cross-sections for crust, interpretations from the IRIS Deep-Seismic Refraction Line, and to a lesser extent by the available gross results from shear-wave splitting and receiver function analysis. The gravity model provides probable solutions for the first time on geometric configuration and geophysical identification: a) for the seaward margin of the mid-Tertiary Mafic Crust (TMC) below sediment cover of the Asir pediment that coincides with the 400 m threshold elevation. This signifies an anomalous uplift at the rifting phase. Moho below TMC extends from 10 - 22 km depth across HAE and west margin of AIP, b). Thinned continental crust below the Asir margin whose upper layer coincides with a seismic reflector is at about 22 km depth, c). Rift-margin characteristic detachment fault associated with basaltic flows on top surface of TMC at its inner margin, d). Two geologically mapped low-angle normal faults dipping to the east developed between the basic rocks intruding the AIP and e). felsic pluton farther east within AS. Large scale igneous activity followed by intense deformation affecting AIP clearly owes their origin to the rifting architecture of the AS at the Red Sea extensional margin. 展开更多
关键词 Shield-margin MAFIC CRUST Asir IGNEOUS Province Seismic MOHO 2D Gravity CRUSTAL model Red Sea Ex-tensional margin
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Margins模型及其在流行病学交互作用分析中的应用
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作者 殷国桓 董子钰 +2 位作者 阿木吉力特 叶泓 许群 《环境卫生学杂志》 2025年第9期786-791,共6页
边际效应(margins)模型作为一种基于回归的边际效应估计方法,近年来在环境健康研究中展现出独特的交互作用识别能力,尤其适用于揭示复杂暴露组合下多元交互结构的方向与强度。本文系统梳理了margins模型在环境流行病学领域的理论基础与... 边际效应(margins)模型作为一种基于回归的边际效应估计方法,近年来在环境健康研究中展现出独特的交互作用识别能力,尤其适用于揭示复杂暴露组合下多元交互结构的方向与强度。本文系统梳理了margins模型在环境流行病学领域的理论基础与实际应用,结合多种重金属混合暴露研究案例,探讨其在不同健康结局中的适用性、建模策略及解释优势。与传统交互项回归相比,margins模型可在控制协变量基础上定量刻画三元及以上交互结构,并提供明确的方向性判断;相较贝叶斯核机器回归、加权分位数和回归等非参数模型,其在高阶交互构建与亚群体分层解释方面具备良好扩展性。尽管该方法在非线性建模、高维变量选择与可视化表达方面仍存在一定局限,但其与贝叶斯方法、惩罚回归与机器学习技术的融合正在拓展其理论边界与应用前景。本文认为,margins模型有望在未来多暴露-多结局的研究框架中成为识别关键交互结构、支持因果推断与风险分层的核心工具。 展开更多
关键词 边际效应模型 多元交互作用 环境流行病学 混合暴露 流行病学
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人文社科职称结构对科研成果的影响机制研究
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作者 俞立平 《决策与信息》 2026年第3期62-74,共13页
职称结构对人文社科科研成果会产生较大影响,但相关领域的理论与实证研究比较薄弱。基于对人文社科科研成果作用机制的研究,采用面板数据模型、分位数回归模型、面板门槛回归模型研究两者之间的关系,并采用BP人工神经网络模型进行稳健... 职称结构对人文社科科研成果会产生较大影响,但相关领域的理论与实证研究比较薄弱。基于对人文社科科研成果作用机制的研究,采用面板数据模型、分位数回归模型、面板门槛回归模型研究两者之间的关系,并采用BP人工神经网络模型进行稳健性检验后发现:人文社科高级职称比例对科研成果同时具有正向机制和负向机制;高级职称比例在促进科研成果方面的作用有待提高;高级职称比例与研发人员协调性不佳;当科研成果从中等水平提高时,高级职称比例的弹性系数也逐步提高;随着高级职称比例提高,其对科研成果的弹性逐步降低;研发经费的绩效最低而研发人员的绩效最高。 展开更多
关键词 人文社科 职称结构 绩效 边际效应 面板门槛模型
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北极东北航道、航运距离与东亚出口增长——基于出口三元边际的机制探讨
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作者 杨来科 姜苗苗 《中国海洋大学学报(社会科学版)》 2026年第2期32-45,共14页
北极东北航道开通将使东亚与欧洲间的航运距离大幅缩短。研究使用航运距离替代传统引力模型中的地理距离,考察北极东北航道开通对东亚出口贸易总量的影响,并从出口三元边际(出口产品广度、产品数量与产品价格)视角识别北极东北航道开通... 北极东北航道开通将使东亚与欧洲间的航运距离大幅缩短。研究使用航运距离替代传统引力模型中的地理距离,考察北极东北航道开通对东亚出口贸易总量的影响,并从出口三元边际(出口产品广度、产品数量与产品价格)视角识别北极东北航道开通对东亚出口增长的驱动力。研究发现:北极东北航道开通将成为东亚出口增长的新动力。机制分析显示,航运距离缩短对东亚出口规模的拉动主要以“数量增长为主,广度增长为辅”,价格增长的贡献率相对较小。北极东北航道开通在促进东亚出口产品数量大幅提升的同时,还会在一定程度上刺激东亚出口结构的升级,表现为出口产品多元化。异质性分析表明,无论是在东亚内部不同经济体之间,还是在不同出口目的国之间,北极东北航道开通对拉动东亚出口增长的效应大小和作用渠道都存在较大差异。 展开更多
关键词 北极东北航道 航运距离 出口增长 引力模型 三元边际
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调度效益最大的水口电站调频投运率提升策略
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作者 谢如昌 卢垚键 张验科 《电力系统及其自动化学报》 北大核心 2026年第2期69-75,共7页
为寻求水口电站在不同入库流量下参与调频时调度效益最大的机组投运率提升策略,耦合微观经济学中边际效益的概念,将水量视为提供“发电”和“调频辅助服务”2种“产品”的“原料”,基于1 m^(3)水所能产生的发电边际效益和调频边际效益... 为寻求水口电站在不同入库流量下参与调频时调度效益最大的机组投运率提升策略,耦合微观经济学中边际效益的概念,将水量视为提供“发电”和“调频辅助服务”2种“产品”的“原料”,基于1 m^(3)水所能产生的发电边际效益和调频边际效益之和最大为目标,建立调度效益最大模型,并针对出库流量一定时的弃水调频和基于优化分配预报来水调频这2种不同情形,给出水口电站调频机组投运率提升策略。结果表明,在不同入库流量和不同预报水平下,所提方法可以达到通过优化调频机组数量和合理动用水库水量来提升水口电站调频投运率,从而实现水口电站调度效益最大化,为水口电站制定参与调频辅助服务市场策略提供了参考。 展开更多
关键词 边际效益 调度效益最大模型 洪水退水期 预报水平 水口电站
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一种新的边际期望损失预测方法及其应用
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作者 金武 王江涛 周希瑀 《统计与决策》 北大核心 2026年第3期52-58,共7页
边际期望损失(MES)是一种重要的系统性风险度量指标。如何及时、准确、便捷地估计或预测MES,对于动态防范系统性风险具有重要的作用。文章从边际期望损失的定义出发,通过等价交换将其转换成一种条件期望,提出一种预测MES的两步方法。新... 边际期望损失(MES)是一种重要的系统性风险度量指标。如何及时、准确、便捷地估计或预测MES,对于动态防范系统性风险具有重要的作用。文章从边际期望损失的定义出发,通过等价交换将其转换成一种条件期望,提出一种预测MES的两步方法。新方法既能有效规避传统方法的模型设定偏误,又能将金融时间序列的典型特征融于MES的预测分析中,还能为将外生变量和神经网络等机器学习方法用于预测MES提供有效途径,因而具有更好的预测效果。将新方法和传统方法同时应用于系统重要性银行的识别,结果表明,新方法能更加准确地预测边际期望损失,这进一步验证了新方法的有效性和优越性。 展开更多
关键词 边际期望损失 DCC-GARCH模型 系统性风险 系统重要性银行
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基于直接计数法和动力学模型的横浪中破损船舶倾覆概率计算研究
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作者 段建文 马宁 史琪琪 《中国舰船研究》 北大核心 2026年第1期63-70,共8页
[目的]旨在基于直接计数法和动力学模型对横浪瘫船状态下破损船舶的倾覆概率进行计算分析,进而改进现行破损船舶稳性评估规范中,基于剩余稳性参数对倾覆概率进行保守估计的方法。[方法]根据所建动力学模型综合考虑波浪−船体−进舱水的耦... [目的]旨在基于直接计数法和动力学模型对横浪瘫船状态下破损船舶的倾覆概率进行计算分析,进而改进现行破损船舶稳性评估规范中,基于剩余稳性参数对倾覆概率进行保守估计的方法。[方法]根据所建动力学模型综合考虑波浪−船体−进舱水的耦合效应。对于波浪−船体耦合,采用瞬时湿表面压力积分方法计算非线性船体回复力和Froude−Krylov力;通过STF方法和脉冲响应函数法计算辐射力和绕射力;结合试验获得的破损船舶横摇阻尼,考虑流体黏性的影响。对于波浪−进舱水耦合效应,采用修正的伯努利方程,计算破口处的水体流入流出速率。对于船体−进舱水耦合,采用集中质量法计算进水晃荡力,同时通过瞬时湿表面压力积分方法考虑进水对船体的静压力。对于进水的黏性耗散作用,采用半经验公式进行近似计算。基于IMO规范和上述动力学模型,采用直接计数法计算破损船舶倾覆概率,并将其表示为时间的边际概率函数。[结果]将模型应用于破损船舶标准模型DTMB 5415,开展横摇运动响应和倾覆概率计算,主要结果如下:1)基于动力学模型计算得到的横摇运动响应结果,与试验结果对比显示,峰值对应周期附近的相对误差均在20%以内;2)该破损船模在30 min内的倾覆概率随有义波高的增大而升高,当波浪跨零周期接近船舶破损后的横摇固有周期时,倾覆概率达到最大值。[结论]研究表明,对于横浪中破损船舶倾覆概率,采用所提方法计算能够得到较为客观准确的结果。 展开更多
关键词 破损船舶 稳性 倾覆概率 动力学模型 直接计数法 边际概率函数 横浪 耦合效应
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基于改进TimeGAN数据增强的用户窃电识别研究
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作者 吴佐平 王宏岩 +1 位作者 张千福 谢青 《电气传动》 2026年第1期75-81,共7页
用户窃电是电网电能非技术损失的主要原因,对电力系统造成了巨大的经济损失和资源浪费。相较于大量用户正常用电样本,窃电用户属于少数类样本,而传统窃电分类方法在样本稀疏或失衡情况下表现不佳。由此,提出一种基于改进时间序列生成对... 用户窃电是电网电能非技术损失的主要原因,对电力系统造成了巨大的经济损失和资源浪费。相较于大量用户正常用电样本,窃电用户属于少数类样本,而传统窃电分类方法在样本稀疏或失衡情况下表现不佳。由此,提出一种基于改进时间序列生成对抗网络(TimeGAN)数据增强的用户窃电分类方法,使用TimeGAN对原始小样本窃电数据进行增强,生成与原始数据分布相似的增广样本,考虑到增广样本存在噪声或不可信等问题,利用马氏距离评估增广样本的质量,完成不可信样本剔除。通过卷积神经网络(CNN)对数据增强后的用电负荷数据进行特征提取,采用长短时记忆网络(LSTM)提取特征量的时序相关性并完成特征分类,进一步,利用麻雀搜索算法(SSA)对CNN-LSTM网络进行参数优化,提高模型检测精度。实验结果表明,所提方法可有效解决用户窃电行为识别中样本不平衡的二分类问题。 展开更多
关键词 TimeGAN模型 马氏距离 麻雀搜索算法(SSA) 窃电识别
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青藏高原北缘莫霍错断构造变形特征的数值模拟
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作者 周书红 张怀 +4 位作者 石耀霖 孙云强 李倩 梁春涛 张咏梅 《地球物理学报》 北大核心 2026年第2期589-603,共15页
青藏高原北缘双脉冲远震P波成像表明,东昆仑—柴达木边界处不到5 km的范围内存在15~20 km的莫霍错断,但其动力学构造特征及影响因素尚不明确.本文根据地震波成像结果建立了二维黏弹性有限元模型,定量分析在重力驱动下的剖面速度场和应... 青藏高原北缘双脉冲远震P波成像表明,东昆仑—柴达木边界处不到5 km的范围内存在15~20 km的莫霍错断,但其动力学构造特征及影响因素尚不明确.本文根据地震波成像结果建立了二维黏弹性有限元模型,定量分析在重力驱动下的剖面速度场和应变率场,并讨论了陡坎倾角、地表高程、黏滞系数及上地幔密度大小对莫霍错断随时间变化的影响.结果表明,剖面速度场随时间逐渐减小并呈顺时针旋转趋势,且速度场的旋转中心随时间从陡坎中部逐渐转移到陡坎深部拐角下方.剖面的主应变率场整体上呈顺时针旋转,且主应变率和最大剪应变率在莫霍面陡坎的拐角处附近表现为应变集中.莫霍错断随时间逐渐趋于平缓,在3 Myrs以前莫霍错断变缓趋势较为明显,5 Myrs之后变缓趋势显著降低.研究表明,上地幔黏滞系数的大小是影响莫霍错断随时间变平缓的主要因素,较低的上地幔黏滞系数可促进莫霍面陡坎被拉平.此外,较小的陡坎倾角、较大的上地幔密度以及松潘—甘孜地块与柴达木盆地之间的高地形起伏均使得莫霍错断趋于平缓.同时,本研究也表明东昆仑—柴达木地块下方存在质量转移,对于认识青藏高原向北扩展的动力学机制以及莫霍错断的动力学特征有重要的意义. 展开更多
关键词 青藏高原北缘 有限元模型 莫霍错断 速度场 应变率场
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基于AGSCOA-Stacking特征加权的船用钢板焊接余量预测
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作者 谢久超 苌道方 《计算机工程》 北大核心 2026年第1期414-426,共13页
为了提升钢板焊接的精度,提高船体质量和建造效率,提出一种自适应黄金正弦螯虾优化算法(AGSCOA)-Stacking特征加权代理模型的方法,用于解决船用钢板焊接余量预测问题。首先,基于Stacking集成学习策略,根据所提出的PC指标,从多种机器学... 为了提升钢板焊接的精度,提高船体质量和建造效率,提出一种自适应黄金正弦螯虾优化算法(AGSCOA)-Stacking特征加权代理模型的方法,用于解决船用钢板焊接余量预测问题。首先,基于Stacking集成学习策略,根据所提出的PC指标,从多种机器学习模型中筛选出兼具高预测精度和差异性的基学习器。其次,提出一种特征加权方法,针对所筛选基学习器的预测性能进行自适应特征加权,从而提高模型的泛化能力。最后,对传统螯虾优化算法进行多方面改进,引入正交折射反向学习机制来改进种群初始化,确保初始种群质量;提出自适应Lévy飞行策略来优化探索阶段,避免陷入局部最优;引入黄金正弦算法改进开发阶段,平衡全局搜索与局部开发能力。利用改进后的AGSCOA对代理模型进行多参数优化,从而提升模型预测精度。实验结果表明,AGSCOA在优化性能和收敛速度上表现出色,所提出的代理模型相比线性加权集成学习代理模型、AGSCOA-SVR、AGSCOA-ET和AGSCOA-RF具有更高的预测精度,均方根误差(RMSE)分别降低了14.29%、35.78%、17.48%和22.31%。 展开更多
关键词 焊接余量预测 Stacking集成学习 代理模型 螯虾优化算法 折射反向学习机制 黄金正弦算法
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西藏冈底斯南缘新生代隆升剥露历史及地质意义
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作者 韩飞 李建江 +10 位作者 秦宇龙 赵海波 杨学俊 叶春林 李峥 贾小川 黄柏鑫 张彤 熊昌利 黄永高 罗改 《地学前缘》 北大核心 2026年第2期440-450,共11页
宏伟高大的青藏高原隆升形式和时限是地学界长期关注的课题。为了揭示其隆升机制及剥蚀过程,对西藏冈底斯南缘奴玛地区花岗岩进行低温热年代学研究,共获得7组磷灰石裂变径迹实验数据,裂变径迹年龄为30~22 Ma,皆晚于白垩世和始新世花岗... 宏伟高大的青藏高原隆升形式和时限是地学界长期关注的课题。为了揭示其隆升机制及剥蚀过程,对西藏冈底斯南缘奴玛地区花岗岩进行低温热年代学研究,共获得7组磷灰石裂变径迹实验数据,裂变径迹年龄为30~22 Ma,皆晚于白垩世和始新世花岗岩体的形成年龄,基本记录了晚渐新世—早中新世阶段冈底斯南缘隆升冷却历史。磷灰石平均径迹长度为(13.2±1.8)~(14.3±1.8)μm,均小于原始径迹长度(16±1)μm,表明磷灰石经历过较强的退火作用。磷灰石热史模拟显示,冈底斯南缘奴玛地区经历了一个持续隆升冷却过程,整体隆升幅度为6603~7443 m,隆升速率为0.27~0.31 mm/a。隆升冷却过程大致可分为3个阶段:40~20 Ma、20~10 Ma和10 Ma至今。3个阶段分别对应印度-欧亚大陆俯冲碰撞、冈底斯构造带大型逆冲推覆构造运动和南北向伸展运动3次重大地质事件。此次研究丰富了青藏高原渐新世隆升机制及模型,同时对早期形成的矿床能否得以保存具有重要的指示意义。 展开更多
关键词 冈底斯南缘 隆升 磷灰石 裂变径迹 热史模拟
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