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Species-specific,pan-European diameter increment models based on data of 2.3 million trees
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作者 Mart-Jan Schelhaas Geerten M Hengeveld +11 位作者 Nanny Heidema Esther Thurig Brigitte Rohner Giorgio Vacchiano Jordi Vayreda John Redmond Jaroslaw Socha Jonas Fridman Stein Tomter Heino Polley Susana Barreiro Gert-Jan Nabuurs 《Forest Ecosystems》 SCIE CSCD 2018年第3期277-295,共19页
Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obta... Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obtained from National Forest Inventories or from long-term research plots. Many of these models include country-and location-specific predictors, such as site quality indices that may aggregate climate, soil properties and topography effects. Consequently, it is not sensible to compare such models among countries, and it is often impossible to apply models outside the region or country they were developed for. However, there is a clear need for more generically applicable but still locally accurate and climate sensitive simulators at the European scale, which requires the development of models that are applicable across the European continent. The purpose of this study is to develop tree diameter increment models that are applicable at the European scale, but still locally accurate. We compiled and used a dataset of diameter increment observations of over 2.3 million trees from 10 National Forest Inventories in Europe and a set of 99 potential explanatory variables covering forest structure, weather, climate, soil and nutrient deposition.Results: Diameter increment models are presented for 20 species/species groups. Selection of explanatory variables was done using a combination of forward and backward selection methods. The explained variance ranged from10% to 53% depending on the species. Variables related to forest structure(basal area of the stand and relative size of the tree) contributed most to the explained variance, but environmental variables were important to account for spatial patterns. The type of environmental variables included differed greatly among species.Conclusions: The presented diameter increment models are the first of their kind that are applicable at the European scale. This is an important step towards the development of a new generation of forest development simulators that can be applied at the European scale, but that are sensitive to variations in growing conditions and applicable to a wider range of management systems than before. This allows European scale but detailed analyses concerning topics like CO2 sequestration, wood mobilisation, long term impact of management, etc. 展开更多
关键词 European forests Diameter increment model Climate change Growth modelling National forest inventory
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Pore water pressure increment model for saturated Nanjing fine sand subject to cyclic loading 被引量:7
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作者 Wang Binghui Chen Guoxing Jin Dandan 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第4期569-576,共8页
Three groups of dynamic triaxial tests were performed for saturated Nanjing fine sand subjected to uniform cyclic loading. The tested curves of the excess pore water pressure (EPWP) ratio variation with the ratio of... Three groups of dynamic triaxial tests were performed for saturated Nanjing fine sand subjected to uniform cyclic loading. The tested curves of the excess pore water pressure (EPWP) ratio variation with the ratio of the number of cycles are provided. The concept of the EPWP increment ratio is introduced and two new concepts of the effective dynamic shear stress ratio and the log decrement of effective stress are defined. It is found that the development of the EPWP increment ratio can be divided into three stages: descending, stable and ascending. Furthermore, at the stable and ascending stages, a satisfactory linear relationship is obtained between the accumulative EPWP increment ratio and natural logarithm of the effective dynamic shear stress ratio. Accordingly, the EPWP increment ratio at the number of cycles N has been deduced that is proportional to the log decrement of effective stress at the cycle number N-l, but is independent of the cyclic stress amplitude. Based on the analysis, a new EPWP increment model for saturated Nanjing fine sand is developed from tested data fitting, which provides a better prediction of the curves of EPWP generation, the number of cycles required for initial liquefaction and the liquefaction resistance. 展开更多
关键词 cyclic loading Nanjing fine sand EPWP model EPWP increment ratio effective dynamic shear stress ratio logarithmic decrement of effective stress
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“Products-Knowledge” Two-Dimensional Increment Model of Fashion Industry Value Chain Based on Industry Analysis
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作者 刘畅 黄震宇 《Journal of Donghua University(English Edition)》 EI CAS 2016年第4期660-664,共5页
Fashion industry has a complex characteristic for it spans the first, second, and third industries. In addition, the characteristic of creative industry has high value-added for its knowledge outputting, which makes t... Fashion industry has a complex characteristic for it spans the first, second, and third industries. In addition, the characteristic of creative industry has high value-added for its knowledge outputting, which makes the traditional value-added analysis based on supply chain not easy and good enough to interpret its industry value-added features. From the perspective of "products-knowledge" two-dimensional analysis,a fashion industry value chain increment model is built,by simulating the process of "product flow" and "information flow" value-added. The fashion industry value chain increment model provides an effective way for the enterprise strategy formulation and production strategy adjustment. 展开更多
关键词 fashion formulation adjustment creative return ledge increment enough manufacture itself
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An incremental contact model for line contact of elastic rough surfaces
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作者 Sihe Wang Weike Yuan +1 位作者 Xuanming Liang Gangfeng Wang 《Acta Mechanica Sinica》 2025年第4期97-106,共10页
In this paper,an incremental contact model is developed for the elastic self-affine fractal rough surfaces under plane strain condition.The contact between a rough surface and a rigid plane is simplified by the accumu... In this paper,an incremental contact model is developed for the elastic self-affine fractal rough surfaces under plane strain condition.The contact between a rough surface and a rigid plane is simplified by the accumulation of identical line contacts with half-width given by the truncated area divided by the contact patch number at varying heights.Based on the contact stiffness of two-dimensional flat punch,the total stiffness of rough surface is estimated,and then the normal load is calculated by an incremental method.For various rough surfaces,the approximately linear load-area relationships predicted by the proposed model agree well with the results of finite element simulations.It is found that the real average contact pressure depends significantly on profile properties. 展开更多
关键词 Elastic line contact Rough surfaces Contact area incremental contact model
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An Incremental Model Transfer Method for Complex Process Fault Diagnosis 被引量:5
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作者 Xiaogang Wang Xiyu Liu Yu Li 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第5期1268-1280,共13页
Fault diagnosis is an important measure to ensure the safety of production, and all kinds of fault diagnosis methods are of importance in actual production process. However, the complexity and uncertainty of productio... Fault diagnosis is an important measure to ensure the safety of production, and all kinds of fault diagnosis methods are of importance in actual production process. However, the complexity and uncertainty of production process often lead to the changes of data distribution and the emergence of new fault classes, and the number of the new fault classes is unpredictable. The reconstruction of the fault diagnosis model and the identification of new fault classes have become core issues under the circumstances. This paper presents a fault diagnosis method based on model transfer learning and the main contributions of the paper are as follows: 1) An incremental model transfer fault diagnosis method is proposed to reconstruct the new process diagnosis model. 2) Breaking the limit of existing method that the new process can only have one more class of faults than the old process, this method can identify M faults more in the new process with the thought of incremental learning. 3) The method offers a solution to a series of problems caused by the increase of fault classes. Experiments based on Tennessee-Eastman process and ore grinding classification process demonstrate the effectiveness and the feasibility of the method. 展开更多
关键词 COMPLEX process FAULT DIAGNOSIS incrementAL LEARNING model TRANSFER
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Sandbox Modeling of the Fault-increment Pattern in Extensional Basins 被引量:6
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作者 Geng Changbo Tong Hengmao +1 位作者 He Yudan Wei Chunguang 《Petroleum Science》 SCIE CAS CSCD 2007年第2期29-34,共6页
Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins. Experimental results showed that the tectonic action mode of boundaries and the shape of major bo... Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins. Experimental results showed that the tectonic action mode of boundaries and the shape of major boundary faults control the formation and evolution of faults in extensional basins. In the process of extensional deformation, the increase in the number and length of faults was episodic, and every 'episode' experienced three periods, strain-accumulation period, quick fault-increment period and strain-adjustment period. The more complex the shape of the boundary fault, the higher the strain increment each 'episode' experienced. Different extensional modes resulted in different fault-increment patterns. The horizontal detachment extensional mode has the 'linear' style of fault-increment pattern, while the extensional mode controlled by a listric fault has the 'stepwise' style of fault-increment pattern, and the extensional mode controlled by a ramp-flat boundary fault has the 'stepwise-linear' style of fault-increment pattern. These fault-increment patterns given above could provide a theoretical method of fault interpretation and fracture prediction in extensional basins. 展开更多
关键词 Extensional basin sandbox modeling fault-increment pattern boundary fault
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INCREMENTAL MICRO-MECHANICAL MODEL OF PLAIN WOVEN FABRIC
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作者 ZhangYitong HaoYongjiang LiCuiyu 《Acta Mechanica Solida Sinica》 SCIE EI 2004年第2期131-139,共9页
Warp yarns and weft yarns of plain woven fabric are the principal axes of mate- rial of fabric. They are orthogonal in their original con?guration, but are obliquely crisscross in deformed con?guration in general. I... Warp yarns and weft yarns of plain woven fabric are the principal axes of mate- rial of fabric. They are orthogonal in their original con?guration, but are obliquely crisscross in deformed con?guration in general. In this paper the expressions of incremental components of strain tensor are derived, the non-linear model of woven fabric is linearized physically and its geometric non-linearity survives. The convenience of determining the total deformation is shown by the choice of the coordinate system of the principal axes of the material, with the convergence of the incremental methods illustrated by examples. This incremental model furnishes a basis for numerical simulations of fabric draping and wrinkling based on the micro-mechanical model of fabric. 展开更多
关键词 micro-weaving structure MICRO-MECHANICS incremental constitutive model prin- cipal axes of material woven fabric incremental methods
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A Modular Incremental Model for English Full Parsing
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作者 孟遥 Li +4 位作者 Sheng Zhao Tiejun Zhang Jing 《High Technology Letters》 EI CAS 2003年第2期57-60,共4页
In this paper, we present a modular incremental statistical model for English full parsing. Unlike other full parsing approaches in which the analysis of the sentence is a uniform process, our model separates the full... In this paper, we present a modular incremental statistical model for English full parsing. Unlike other full parsing approaches in which the analysis of the sentence is a uniform process, our model separates the full parsing into shallow parsing and sentence skeleton parsing. In shallow parsing, we finish POS tagging, Base NP identification, prepositional phrase attachment and subordinate clause identification. In skeleton parsing, we use a layered feature-oriented statistical method. Modularity possesses the advantage of solving different problems in parsing with corresponding mechanisms. Feature-oriented rule is able to express the complex lingual phenomena at the key point if needed. Evaluated on Penn Treebank corpus, we obtained 89.2% precision and 89.8% recall. 展开更多
关键词 incremental statistical model shallow parsing skeleton parsing feature-oriented rule
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Incremental 4D-VAR assimilation scheme based on Lorenz model 被引量:1
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作者 WANG Xidong XU Dongfeng XU Xiaohua 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2008年第z1期93-100,共8页
Four-dimensional variational(4D-VAR) data assimilation method is a perfect data assimilation solution in theory, but the computational issue is quite difficult in operational implementation.The incremental 4D-VAR assi... Four-dimensional variational(4D-VAR) data assimilation method is a perfect data assimilation solution in theory, but the computational issue is quite difficult in operational implementation.The incremental 4D-VAR assimilation scheme is set up in order to reduce the computational cost. It is shown that the accuracy of the observations, the length of the assimilation window and the choice of the first guess have an important influence on the assimilation outcome through the contrast experiment. Compared with the standard 4D-VAR assimilation scheme, the incremental 4D-VAR assimilation scheme shows its advantage in the computation speed through an assimilation experiment. 展开更多
关键词 4D-VAR assimilation incremental 4D-VAR assimilation Lorenz model
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Individual Tree Diameter Increment Model for Chinese Fir Plantation Based on Two-Level Linear Mixed Effects Models 被引量:1
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作者 Li Chunming 《Chinese Forestry Science and Technology》 2012年第3期60-61,共2页
Based on a multilevel linear mixed model approach,an individual diameter increment model was developed for fir plantation trees growing in Jiangxi Province.The data set used in this study came from long-term permanent... Based on a multilevel linear mixed model approach,an individual diameter increment model was developed for fir plantation trees growing in Jiangxi Province.The data set used in this study came from long-term permanent research plots.The database consists of total of 82 counties,365 plots, 5 416 trees and 16 248 observations.The paper chose mixed effects models instead of regression analysis approach because it allows for proper treatment of error terms and correlation in a repeated measures analysis framework.The model was defined as a mixed linear model with parameter random effect of plot,area or plot and area simultaneous.In addition the heteroscedasticity and correlation was taken into account.Mixed model calibration of diameter increment was carried out with the independent data using a different sample of complementary observations.The result showed that the total stand basal area,the diameter of target trees,the ratio of basal area of larger trees to target tree diameter,and altitude were found to be significant predictors.Both the fitting model and the calibrated model mean a substantial improvement compared with the classical approach widely used in forest management.After taking into account reasonable variance function of heteroscedasticity and correlation,the model shows better of goodness of fit than only taking into account parameter random effects.This type of modeling methodology shows flexible,precise and accurate. 展开更多
关键词 individual DIAMETER increment HETEROSCEDASTICITY correlation structure linear mixed model FIR
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协方差结构辅助的全增量线性化模型自适应目标检测方法
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作者 田晗 崔珂瑄 高永婵 《电波科学学报》 北大核心 2025年第2期360-370,共11页
针对多通道阵列雷达探测目标时有限训练样本与目标信息不准确等敏感因素导致检测性能急剧下降的问题,提出了协方差结构辅助的全增量线性化模型自适应目标检测方法。该方法采取联合处理思想,将目标不准确信息通过阵列导向矢量建模为全增... 针对多通道阵列雷达探测目标时有限训练样本与目标信息不准确等敏感因素导致检测性能急剧下降的问题,提出了协方差结构辅助的全增量线性化模型自适应目标检测方法。该方法采取联合处理思想,将目标不准确信息通过阵列导向矢量建模为全增量线性化模型,然后利用酉矩阵变换设计协方差结构辅助的检测,并将该检测问题转化为分数优化问题,再通过白化处理并优化求解推导出最终检测统计量。数值仿真结果表明,通过辅助利用协方差结构信息优化全增量线性化模型,有效改善了目标在复杂敏感环境下的检测性能,相比传统检测方法,在特定参数条件下自适应样本量减少时检测性能仍然保持最优。 展开更多
关键词 阵列雷达 自适应目标检测 协方差结构 目标信息 全增量线性化模型
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基于MRAS参数辨识的永磁同步电机增量式模型预测电流控制研究
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作者 李耀华 郭伟超 +7 位作者 王钦政 王自臣 高赛 种国臣 徐志雄 刘亚辉 张茜 黄汉旋 《电机与控制应用》 2025年第10期1050-1062,共13页
【目的】为解决永磁同步电机(PMSM)模型预测电流控制(MPCC)的参数失配问题,采用增量式MPCC与模型参考自适应系统(MRAS)进行参数辨识,以提高控制系统的参数鲁棒性。【方法】首先建立基于增量式模型的MPCC系统以消除磁链参数,同时对增量式... 【目的】为解决永磁同步电机(PMSM)模型预测电流控制(MPCC)的参数失配问题,采用增量式MPCC与模型参考自适应系统(MRAS)进行参数辨识,以提高控制系统的参数鲁棒性。【方法】首先建立基于增量式模型的MPCC系统以消除磁链参数,同时对增量式MPCC的参数敏感性进行分析,其中电阻参数失配对电流预测效果影响很小,可忽略不计。因此基于dq轴电流,采用MRAS仅辨识dq轴电感,从而避免欠秩问题。【结果】基于Matlab/Simulink与STM32平台进行了仿真分析与实时性验证。结果表明,MRAS可精确辨识dq轴电感参数;虽然增量式MPCC与MRAS控制模型需要设置电阻参数,但电阻参数失配对dq轴电感的辨识结果影响较小;加入的MRAS参数辨识系统并不额外增加较大的计算负担,具有较好的实时性表现。【结论】对于PMSM的dq轴电感、磁链与电阻4个参数,采用增量式MPCC消除了磁链参数,而电阻参数无需精确辨识,仅需通过MRAS辨识dq轴电感。MRAS控制模型和增量式MPCC的电阻参数失配对控制性能基本无影响,从而有效提升了PMSM MPCC参数失配鲁棒性。 展开更多
关键词 永磁同步电机 模型预测电流控制 增量式模型 模型参考自适应系统 参数辨识
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基于增量学习的社交网络链路预测 被引量:1
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作者 舒坚 陈芷晨 《工程科学与技术》 北大核心 2025年第2期1-11,共11页
社交网络中,节点间存在多种关系类型,节点数量会随着时间的推移而变化,这种异质性和动态性给链路预测任务带来极大的挑战。因此,本文提出一种基于增量学习的社交网络链路预测方法(incremental learning social networks link prediction... 社交网络中,节点间存在多种关系类型,节点数量会随着时间的推移而变化,这种异质性和动态性给链路预测任务带来极大的挑战。因此,本文提出一种基于增量学习的社交网络链路预测方法(incremental learning social networks link prediction,IL-SNLP)。通过对网络进行分层,使每一层网络只包含一种关系类型,以更好地获取节点在每种关系类型下的语义信息;针对网络的动态性,利用时序随机游走捕获社交网络中的局部结构信息和时序信息;针对增量数据,采用增量式更新随机游走策略对历史随机游走序列进行更新。通过增量式skip-gram模型从随机游走序列中提取新出现节点的特征,并进一步更新历史节点的特征;针对网络的异质性,采用概率模型提取不同关系类型之间的因果关系关联程度,并将其作用于每一层的节点特征,以改善不同关系层下节点特征表现能力;利用多层感知机构建节点相互感知器,挖掘节点间建立连接时的相互贡献,实现更高的链路预测准确率。实验结果表明,在3个真实的社交网络数据集上,IL-SNLP方法的ROC曲线下的面积(AUC)和F1分数比基线方法分别提高了10.08%~67.60%和1.76%~64.67%,提升了预测性能;对于增量数据,只需要少次迭代就能保持预测模型的性能,提高了模型训练的速度;与未采用增量学习技术的IL-SNLP−方法相比,IL-SNLP方法在时间效率上提升了30.78%~257.58%,显著缩短了模型的运行时长。 展开更多
关键词 社交网络 链路预测 增量学习 时序随机游走 概率模型
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基于扩散模型的增量式时间序列缺失值填充算法
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作者 冯兴杰 卞兴鹏 +1 位作者 冯小荣 王兴隆 《计算机应用》 北大核心 2025年第8期2582-2591,共10页
时间序列中的数据缺失是一个普遍存在的问题,这会给后续分析带来困难,对缺失值的有效填充是提升数据质量以及挖掘数据价值的重要着力点。然而,现有的填充算法在特征提取方面多沿用时序预测任务的面向非缺失数据的注意力模块,而对含有缺... 时间序列中的数据缺失是一个普遍存在的问题,这会给后续分析带来困难,对缺失值的有效填充是提升数据质量以及挖掘数据价值的重要着力点。然而,现有的填充算法在特征提取方面多沿用时序预测任务的面向非缺失数据的注意力模块,而对含有缺失值的时间序列的时空特征提取效果欠佳。此外,现有的填充算法缺乏对填充规律的深入研究,这让它们对于填充过程中的阶段性填充值利用不足,导致填充的准确率有待进一步提升。为了解决上述问题,提出一种基于扩散模型的增量式时间序列缺失值填充算法(I2TDM)。I2TDM在经典扩散模型中融入时序注意力模块,以增强对于含有缺失值的时间序列的特征提取能力。同时,设计一个新颖的增量式填充算法,使用增量选择模块保留部分阶段性填充值,从而提升填充算法的稳定性与准确率。在空气质量指数(AQI)、电力变压器油温(ETT)和天气(Weather)3个公开数据集上的填充实验结果表明,I2TDM相较于CSDI、SAITS和PriSTI等基线模型在平均绝对误差(MAE)指标上至少降低了2.92%,在均方根误差(RMSE)指标上至少降低了3.49%。可见,I2TDM能够有效提升时间序列缺失值填充的准确率。 展开更多
关键词 时间序列 缺失值填充 扩散模型 时序注意力 增量式填充
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共母线开绕组永磁同步牵引电机改进级联模型预测控制
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作者 高锋阳 吴银波 +4 位作者 徐昊 史志龙 岳文瀚 孙伟 王高强 《铁道科学与工程学报》 北大核心 2025年第3期1254-1265,共12页
为降低共母线开绕组永磁同步牵引电机三矢量级联模型预测电流控制开关频率和控制系统对电机参数依赖性,提出一种基于变步长自适应线性神经网络(Adaline)可调参数改进级联模型预测电流控制策略。首先,针对共母线开绕组永磁同步牵引电机... 为降低共母线开绕组永磁同步牵引电机三矢量级联模型预测电流控制开关频率和控制系统对电机参数依赖性,提出一种基于变步长自适应线性神经网络(Adaline)可调参数改进级联模型预测电流控制策略。首先,针对共母线开绕组永磁同步牵引电机三矢量级联模型预测电流控制造成开关频率高的原因进行分析,剔除高开关频率和高共模电压的电压矢量,优化备选电压矢量范围,对剩余电压矢量根据其对q轴电流作用效果分组组合寻优和分配作用时间;基于变步长自适应线性神经网络改进PI控制器,使得改进PI控制器兼顾快速性与超调;然后,分析共母线开绕组永磁同步牵引电机模型预测控制参数变化特性,构建系统变步长自适应线性神经网络参数辨识模型,对电机参数分步辨识,形成参数可调节级联模型预测控制;最后,对所提策略和三矢量级联模型预测电流控制进行稳态和动态半实物测试对比。结果表明:所提策略对转矩脉动、零轴电流、总谐波畸变率、开关频率、调速超调都具有很好的抑制效果,避免了传统模型预测控制的多目标代价函数中权重系数整定和参数辨识模型构建欠秩问题,对系统的控制性能有明显的提升作用。研究结果为进一步将共母线开绕组永磁同步牵引电机传动系统应用于机车牵引提供参考。 展开更多
关键词 开绕组永磁同步牵引电机 变步长自适应线性神经网络 级联模型预测 转矩脉动 零轴电流 参数分步辨识 开关频率
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基于增量Kriging模型辅助的双指标采样昂贵高维优化算法
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作者 李二超 唐静 《南京师范大学学报(工程技术版)》 2025年第2期1-13,共13页
针对昂贵的高维多目标优化问题,性能指标选择机制在评估候选解的收敛性与多样性方面发挥了关键作用.然而,由于实际函数求值受限,这些机制在应对昂贵问题时面临挑战.同时,依赖单一指标可能引入偏差,使得平衡种群的收敛性与多样性变得困难... 针对昂贵的高维多目标优化问题,性能指标选择机制在评估候选解的收敛性与多样性方面发挥了关键作用.然而,由于实际函数求值受限,这些机制在应对昂贵问题时面临挑战.同时,依赖单一指标可能引入偏差,使得平衡种群的收敛性与多样性变得困难.为了解决这些问题,本文提出了一种基于增量Kriging模型辅助的双指标采样昂贵高维优化算法.首先,通过引入增量Kriging模型来近似计算昂贵的目标函数,有效降低了计算成本与时间成本.其次,采用一种基于最值双指标选择的随机排序选择机制作为一种有效的模型管理策略,该策略采用I_(ε+)(x,y)和I_(SDE)(x,y)指标同时评估候选解的质量,进一步提高了搜索效率,最终实现了收敛性与多样性的平衡.为验证算法的有效性,在DTLZ和WFG多目标优化测试问题以及实际工程优化问题上进行了测试,并将其与近年来提出的5种优秀的同类型算法进行了结果对比.实验结果表明,本文提出的算法在求解昂贵高维多目标优化问题上具有显著的有效性. 展开更多
关键词 昂贵高维多目标优化 代理辅助进化算法 增量Kriging模型 模型管理 性能指标 填充准则
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基于联邦大模型的网络攻击检测方法研究
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作者 康海燕 张义钒 王楠敏 《电子学报》 北大核心 2025年第6期1792-1804,共13页
为了解决真实Web应用攻击数据数量小、差异性大和攻击载荷多样化导致大模型训练效果差的问题,提出一种基于联邦大模型的网络攻击检测方法(Intrusion Detection methods based on Federal Large Language Model,FLLLMID).首先,提出一种... 为了解决真实Web应用攻击数据数量小、差异性大和攻击载荷多样化导致大模型训练效果差的问题,提出一种基于联邦大模型的网络攻击检测方法(Intrusion Detection methods based on Federal Large Language Model,FLLLMID).首先,提出一种面向大模型微调的联邦学习网络,服务器对客户端本地大模型通过增量数据训练产生的参数,进行增量聚合的方式,提高联邦学习中大模型的参数聚合效率以及避免网络流量数据暴露的问题;其次,基于大模型对代码的理解能力,提出面向应用层数据的攻击检测模型(CodeBERT-LSTM),通过对应用层数据报文进行分析,使用CodeBERT模型对有效字段进行向量编码后,结合长短期记忆网络(Long Short-Term Memory,LSTM)进行分类,实现对Web应用高效的攻击检测任务;最后,实验结果表明,FL-LLMID方法在面向应用层数据的攻击检测任务中准确率达到99.63%,与传统联邦学习相比,增量式学习的效率提升了12个百分点. 展开更多
关键词 联邦学习 大模型 长短期记忆网络 CodeBERT 网络攻击检测 增量聚合
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基于多维度IncDBSCAN的打孔盗油车辆预警方法探讨
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作者 卢兴亚 卢传钊 何建民 《管道保护》 2025年第4期75-81,共7页
打孔盗油事件不但给国家造成巨大经济损失,还可能危害国家能源安全、生态安全和公共安全,对打孔盗油须防患于未然,以避免危害结果的发生。通过深入分析打孔盗油嫌疑车辆的行为特征,引入多维度增量式DBSCAN算法(increment Density-Based ... 打孔盗油事件不但给国家造成巨大经济损失,还可能危害国家能源安全、生态安全和公共安全,对打孔盗油须防患于未然,以避免危害结果的发生。通过深入分析打孔盗油嫌疑车辆的行为特征,引入多维度增量式DBSCAN算法(increment Density-Based Spatial Clustering of Applications with Noise,IncDBSCAN),挖掘公安视频监控车辆抓拍数据中的潜在规律,可有效识别在管道保护区内活动的涉嫌盗油异常车辆。在与传统的支持向量机(Support Vector Machine,SVM)、基于密度带有噪声的空间聚类算法(Density-Based Spatial Clustering of Applications with Noise,DBSCAN)、K均值聚类算法(K-Means Clustering Algorithm,K-Means)的对比试验中,多维度IncDBSCAN模型具有更好的检测效果,其精确率为85%,召回率为82%,F1值为83.4%,均优于其他模型。该方法为输油管道打孔盗油视频智能预警提供了一种新的思路和手段。 展开更多
关键词 打孔盗油 增量聚类 车辆异常检测 预警模型 管道安全
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考虑时域自适应的永磁直驱电机模型预测控制
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作者 赵金阳 杜钦君 +2 位作者 徐执诏 马炳图 吴育桐 《仪表技术与传感器》 北大核心 2025年第1期112-119,共8页
永磁直驱电机运行时负载变化及电机内部参数变化,导致输出转矩产生波动。为提高伺服系统运动性能,提出了一种改进型连续控制集预测转矩控制方法。根据速度误差判断电机的运行状态,利用自适应函数对电机处于暂态、稳态不同工况下在线调... 永磁直驱电机运行时负载变化及电机内部参数变化,导致输出转矩产生波动。为提高伺服系统运动性能,提出了一种改进型连续控制集预测转矩控制方法。根据速度误差判断电机的运行状态,利用自适应函数对电机处于暂态、稳态不同工况下在线调整预测步数、预测步长以及控制周期,采用增量模型消除磁链对预测控制的影响。针对直驱系统易受外部扰动的影响,设计了具有可变增益的龙伯格观测器,使观测器在电机稳态和暂态时分别采用不同的增益,并超前一步观测负载转矩,提高观测器的观测性能。进行了仿真实验,验证所提方法的有效性。 展开更多
关键词 永磁直驱电机 自适应函数 增量模型 模型预测转矩控制 龙伯格观测器
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基于大语言模型的CIL-LLM类别增量学习框架
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作者 王晓宇 李欣 +1 位作者 胡勉宁 薛迪 《计算机科学与探索》 北大核心 2025年第2期374-384,共11页
在文本分类领域,为了提升类别增量学习模型的分类准确率并避免灾难性遗忘问题,提出了一种基于大语言模型(LLM)的类别增量学习框架(CIL-LLM)。CIL-LLM框架通过抽样和压缩环节选取具有代表性的样本,利用较强语言理解能力的LLM基于上下文... 在文本分类领域,为了提升类别增量学习模型的分类准确率并避免灾难性遗忘问题,提出了一种基于大语言模型(LLM)的类别增量学习框架(CIL-LLM)。CIL-LLM框架通过抽样和压缩环节选取具有代表性的样本,利用较强语言理解能力的LLM基于上下文学习提炼关键技能,以这些技能作为分类的依据,从而降低了存储成本;采用关键词匹配环节选取最优技能,以此构建提示词,引导下游弱LLM进行分类,提高了分类的准确性;根据基于知识蒸馏的技能融合环节,不仅实现了技能库的有效拓展和更新,还兼顾了新旧类别特性的学习。对比实验结果表明,在THUCNews数据集上的测试中,与现有的L-SCL方法相比,CIL-LLM框架在所有任务上的平均准确率提升了6.3个百分点,性能下降率降低了3.1个百分点。此外,在消融实验中,经由CIL-LLM框架增强的SLEICL模型相比于原有模型,所有任务的平均准确率提高了10.4个百分点,性能下降率降低了3.3个百分点。消融实验进一步验证了提出的样本压缩、关键词匹配和技能融合环节均对模型的准确率和性能下降率产生了优化效果。 展开更多
关键词 类别增量学习 大语言模型(LLM) 主题分类 知识蒸馏
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