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Federated Multi-Label Feature Selection via Dual-Layer Hybrid Breeding Cooperative Particle Swarm Optimization with Manifold and Sparsity Regularization
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作者 Songsong Zhang Huazhong Jin +5 位作者 Zhiwei Ye Jia Yang Jixin Zhang Dongfang Wu Xiao Zheng Dingfeng Song 《Computers, Materials & Continua》 2026年第1期1141-1159,共19页
Multi-label feature selection(MFS)is a crucial dimensionality reduction technique aimed at identifying informative features associated with multiple labels.However,traditional centralized methods face significant chal... Multi-label feature selection(MFS)is a crucial dimensionality reduction technique aimed at identifying informative features associated with multiple labels.However,traditional centralized methods face significant challenges in privacy-sensitive and distributed settings,often neglecting label dependencies and suffering from low computational efficiency.To address these issues,we introduce a novel framework,Fed-MFSDHBCPSO—federated MFS via dual-layer hybrid breeding cooperative particle swarm optimization algorithm with manifold and sparsity regularization(DHBCPSO-MSR).Leveraging the federated learning paradigm,Fed-MFSDHBCPSO allows clients to perform local feature selection(FS)using DHBCPSO-MSR.Locally selected feature subsets are encrypted with differential privacy(DP)and transmitted to a central server,where they are securely aggregated and refined through secure multi-party computation(SMPC)until global convergence is achieved.Within each client,DHBCPSO-MSR employs a dual-layer FS strategy.The inner layer constructs sample and label similarity graphs,generates Laplacian matrices to capture the manifold structure between samples and labels,and applies L2,1-norm regularization to sparsify the feature subset,yielding an optimized feature weight matrix.The outer layer uses a hybrid breeding cooperative particle swarm optimization algorithm to further refine the feature weight matrix and identify the optimal feature subset.The updated weight matrix is then fed back to the inner layer for further optimization.Comprehensive experiments on multiple real-world multi-label datasets demonstrate that Fed-MFSDHBCPSO consistently outperforms both centralized and federated baseline methods across several key evaluation metrics. 展开更多
关键词 Multi-label feature selection federated learning manifold regularization sparse constraints hybrid breeding optimization algorithm particle swarm optimizatio algorithm privacy protection
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基于注意力增强与边缘感知的脑肿瘤MRI跨模态生成方法
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作者 李好 杨智慧 李丰森 《中国医学物理学杂志》 2026年第1期65-75,共11页
目的:规避脑肿瘤MRI成像过程中存在的时间成本高、伪影多和模态获取不全等问题,研究一种高质量的跨模态脑肿瘤MRI图像生成方法。方法:提出一种融合注意力机制与边缘感知的配准生成对抗网络(AE-RegGAN),对T1模态到T2模态图像的跨模态合成... 目的:规避脑肿瘤MRI成像过程中存在的时间成本高、伪影多和模态获取不全等问题,研究一种高质量的跨模态脑肿瘤MRI图像生成方法。方法:提出一种融合注意力机制与边缘感知的配准生成对抗网络(AE-RegGAN),对T1模态到T2模态图像的跨模态合成,在生成器中引入CoordAttention模块以增强关键区域感知,并结合Sobel边缘检测以强化肿瘤边界表达;在判别器中加入梯度惩罚正则化以提升训练稳定性并缓解模式崩溃问题。结果:在对5760例脑肿瘤MRI数据训练、768例测试中,AE-RegGAN相较于原始RegGAN在局部肿瘤区域的峰值信噪比(PSNR)提升0.51 dB,结构相似性指数(SSIM)提升0.029;在全局图像上PSNR提升0.900 dB,SSIM提升0.032。全局图像配对t检验结果显示平均绝对误差(P=0.0264)、PSNR(P<0.0001)、SSIM(P<0.0001)指标差异均有统计学意义。消融实验进一步验证了注意力与边缘感知模块的有效性。结论:AE-RegGAN在多模态脑部MRI图像合成中表现出更优的结构保持能力与病灶敏感性,为辅助诊断提供了稳定、可信的图像补全方案。 展开更多
关键词 生成对抗网络 脑肿瘤mrI图像生成 注意力机制 边缘感知 梯度正则化
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Numerical estimation of choice of the regularization parameter for NMR T2 inversion 被引量:2
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作者 You-Long Zou Ran-Hong Xie Alon Arad 《Petroleum Science》 SCIE CAS CSCD 2016年第2期237-246,共10页
Nuclear Magnetic inversion is the basis of NMR Resonance (NMR) T2 logging interpretation. The regularization parameter selection of the penalty term directly influences the NMR T2 inversion result. We implemented b... Nuclear Magnetic inversion is the basis of NMR Resonance (NMR) T2 logging interpretation. The regularization parameter selection of the penalty term directly influences the NMR T2 inversion result. We implemented both norm smoothing and curvature smoothing methods for NMR T2 inversion, and compared the inversion results with respect to the optimal regular- ization parameters ((Xopt) which were selected by the dis- crepancy principle (DP), generalized cross-validation (GCV), S-curve, L-curve, and the slope of L-curve methods, respectively. The numerical results indicate that the DP method can lead to an oscillating or oversmoothed solution which is caused by an inaccurately estimated noise level. The (Xopt selected by the L-curve method is occa- sionally small or large which causes an undersmoothed or oversmoothed T2 distribution. The inversion results from GCV, S-curve and the slope of L-curve methods show satisfying inversion results. The slope of the L-curve method with less computation is more suitable for NMR T2 inversion. The inverted T2 distribution from norm smoothing is better than that from curvature smoothing when the noise level is high. 展开更多
关键词 Nmr T2 inversion Tikhonov regularizationVariable substitution Levenberg-Marquardt method regularization parameter selection
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Gamma-ray spectral energy resolution calibration based on locally constrained regularization for scintillation detector response:methodology,numerical,and experimental analysis
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作者 Guo-Feng Yang Wen-Zheng Peng +3 位作者 Dong-Ming Liu Xiao-Long Wu Meng Chen Xiang-Jun Liu 《Nuclear Science and Techniques》 2025年第4期92-104,共13页
Energy resolution calibration is crucial for gamma-ray spectral analysis,as measured using a scintillation detector.A locally constrained regularization method was proposed to determine the resolution calibration para... Energy resolution calibration is crucial for gamma-ray spectral analysis,as measured using a scintillation detector.A locally constrained regularization method was proposed to determine the resolution calibration parameters.First,a Monte Carlo simulation model consistent with an actual measurement system was constructed to obtain the energy deposition distribution in the scintillation crystal.Subsequently,the regularization objective function is established based on weighted least squares and additional constraints.Additional constraints were designed using a special weighting scheme based on the incident gamma-ray energies.Subsequently,an intelligent algorithm was introduced to search for the optimal resolution calibration parameters by minimizing the objective function.The most appropriate regularization parameter was determined through mathematical experiments.When the regularization parameter was 30,the calibrated results exhibited the minimum RMSE.Simulations and test pit experiments were conducted to verify the performance of the proposed method.The simulation results demonstrate that the proposed algorithm can determine resolution calibration parameters more accurately than the traditional weighted least squares,and the test pit experimental results show that the R-squares between the calibrated and measured spectra are larger than 0.99.The accurate resolution calibration parameters determined by the proposed method lay the foundation for gamma-ray spectral processing and simulation benchmarking. 展开更多
关键词 Energy resolution regularization Gaussian broadening Spectral analysis Scintillation detector
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Absorption compensation via structure tensor regularization multichannel inversion
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作者 Liang Bing Zhao Dong-feng +4 位作者 Xia Lian-jun Tang Guo-song Luo Zhen Guan Wen-hua Wang Xue-jing 《Applied Geophysics》 2025年第3期635-646,892,893,共14页
Absorption compensation is a process involving the exponential amplification of reflection amplitudes.This process amplifies the seismic signal and noise,thereby substantially reducing the signal-tonoise ratio of seis... Absorption compensation is a process involving the exponential amplification of reflection amplitudes.This process amplifies the seismic signal and noise,thereby substantially reducing the signal-tonoise ratio of seismic data.Therefore,this paper proposes a multichannel inversion absorption compensation method based on structure tensor regularization.First,the structure tensor is utilized to extract the spatial inclination of seismic signals,and the spatial prediction filter is designed along the inclination direction.The spatial prediction filter is then introduced into the regularization condition of multichannel inversion absorption compensation,and the absorption compensation is realized under the framework of multichannel inversion theory.The spatial predictability of seismic signals is also introduced into the objective function of absorption compensation inversion.Thus,the inversion system can effectively suppress the noise amplification effect during absorption compensation and improve the recovery accuracy of high-frequency signals.Synthetic and field data tests are conducted to demonstrate the accuracy and effectiveness of the proposed method. 展开更多
关键词 Absorption compensation Structure tensor RESOLUTION Signal-to-noise ratio regularization
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Robust visual tracking using temporal regularization correlation filter with high-confidence strategy
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作者 Xiao-Gang Dong Ke-Xuan Li +2 位作者 Hong-Xia Mao Chen Hu Tian Pu 《Journal of Electronic Science and Technology》 2025年第2期81-96,共16页
Target tracking is an essential task in contemporary computer vision applications.However,its effectiveness is susceptible to model drift,due to the different appearances of targets,which often compromises tracking ro... Target tracking is an essential task in contemporary computer vision applications.However,its effectiveness is susceptible to model drift,due to the different appearances of targets,which often compromises tracking robustness and precision.In this paper,a universally applicable method based on correlation filters is introduced to mitigate model drift in complex scenarios.It employs temporal-confidence samples as a priori to guide the model update process and ensure its precision and consistency over a long period.An improved update mechanism based on the peak side-lobe to peak correlation energy(PSPCE)criterion is proposed,which selects high-confidence samples along the temporal dimension to update temporal-confidence samples.Extensive experiments on various benchmarks demonstrate that the proposed method achieves a competitive performance compared with the state-of-the-art methods.Especially when the target appearance changes significantly,our method is more robust and can achieve a balance between precision and speed.Specifically,on the object tracking benchmark(OTB-100)dataset,compared to the baseline,the tracking precision of our model improves by 8.8%,8.8%,5.1%,5.6%,and 6.9%for background clutter,deformation,occlusion,rotation,and illumination variation,respectively.The results indicate that this proposed method can significantly enhance the robustness and precision of target tracking in dynamic and challenging environments,offering a reliable solution for applications such as real-time monitoring,autonomous driving,and precision guidance. 展开更多
关键词 Appearance changes Correlation filter High-confidence strategy Temporal regularization Visual tracking
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Graph-Based Transform and Dual Graph Laplacian Regularization for Depth Map Denoising
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作者 MENG Yaqun GE Huayong +2 位作者 HOU Xinxin JI Yukai LI Sisi 《Journal of Donghua University(English Edition)》 2025年第5期534-542,共9页
Owing to the constraints of depth sensing technology,images acquired by depth cameras are inevitably mixed with various noises.For depth maps presented in gray values,this research proposes a novel denoising model,ter... Owing to the constraints of depth sensing technology,images acquired by depth cameras are inevitably mixed with various noises.For depth maps presented in gray values,this research proposes a novel denoising model,termed graph-based transform(GBT)and dual graph Laplacian regularization(DGLR)(DGLR-GBT).This model specifically aims to remove Gaussian white noise by capitalizing on the nonlocal self-similarity(NSS)and the piecewise smoothness properties intrinsic to depth maps.Within the group sparse coding(GSC)framework,a combination of GBT and DGLR is implemented.Firstly,within each group,the graph is constructed by using estimates of the true values of the averaged blocks instead of the observations.Secondly,the graph Laplacian regular terms are constructed based on rows and columns of similar block groups,respectively.Lastly,the solution is obtained effectively by combining the alternating direction multiplication method(ADMM)with the weighted thresholding method within the domain of GBT. 展开更多
关键词 depth map graph signal processing dual graph Laplacian regularization(DGLR) graph-based transform(GBT) group sparse coding(GSC)
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Mechanical response identification of local interconnections in board- level packaging structures under projectile penetration using Bayesian regularization
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作者 Xu Long Yuntao Hu Irfan Ali 《Defence Technology(防务技术)》 2025年第7期79-95,共17页
Modern warfare demands weapons capable of penetrating substantial structures,which presents sig-nificant challenges to the reliability of the electronic devices that are crucial to the weapon's perfor-mance.Due to... Modern warfare demands weapons capable of penetrating substantial structures,which presents sig-nificant challenges to the reliability of the electronic devices that are crucial to the weapon's perfor-mance.Due to miniaturization of electronic components,it is challenging to directly measure or numerically predict the mechanical response of small-sized critical interconnections in board-level packaging structures to ensure the mechanical reliability of electronic devices in projectiles under harsh working conditions.To address this issue,an indirect measurement method using the Bayesian regularization-based load identification was proposed in this study based on finite element(FE)pre-dictions to estimate the load applied on critical interconnections of board-level packaging structures during the process of projectile penetration.For predicting the high-strain-rate penetration process,an FE model was established with elasto-plastic constitutive models of the representative packaging ma-terials(that is,solder material and epoxy molding compound)in which material constitutive parameters were calibrated against the experimental results by using the split-Hopkinson pressure bar.As the impact-induced dynamic bending of the printed circuit board resulted in an alternating tensile-compressive loading on the solder joints during penetration,the corner solder joints in the edge re-gions experience the highest S11 and strain,making them more prone to failure.Based on FE predictions at different structural scales,an improved Bayesian method based on augmented Tikhonov regulariza-tion was theoretically proposed to address the issues of ill-posed matrix inversion and noise sensitivity in the load identification at the critical solder joints.By incorporating a wavelet thresholding technique,the method resolves the problem of poor load identification accuracy at high noise levels.The proposed method achieves satisfactorily small relative errors and high correlation coefficients in identifying the mechanical response of local interconnections in board-level packaging structures,while significantly balancing the smoothness of response curves with the accuracy of peak identification.At medium and low noise levels,the relative error is less than 6%,while it is less than 10%at high noise levels.The proposed method provides an effective indirect approach for the boundary conditions of localized solder joints during the projectile penetration process,and its philosophy can be readily extended to other scenarios of multiscale analysis for highly nonlinear materials and structures under extreme loading conditions. 展开更多
关键词 Board-level packaging structure High strain-rate constitutive model Load identification Bayesian regularization Wavelet thresholding method
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Full waveform inversion with fractional anisotropic total p-variation regularization
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作者 Bo Li Xiao-Tao Wen +2 位作者 Yu-Qiang Zhang Zi-Yu Qin Zhi-Di An 《Petroleum Science》 2025年第8期3266-3278,共13页
Full waveform inversion is a precise method for parameter inversion,harnessing the complete wavefield information of seismic waves.It holds the potential to intricately characterize the detailed features of the model ... Full waveform inversion is a precise method for parameter inversion,harnessing the complete wavefield information of seismic waves.It holds the potential to intricately characterize the detailed features of the model with high accuracy.However,due to inaccurate initial models,the absence of low-frequency data,and incomplete observational data,full waveform inversion(FWI)exhibits pronounced nonlinear characteristics.When the strata are buried deep,the inversion capability of this method is constrained.To enhance the accuracy and precision of FWI,this paper introduces a novel approach to address the aforementioned challenges—namely,a fractional-order anisotropic total p-variation regularization for full waveform inversion(FATpV-FWI).This method incorporates fractional-order total variation(TV)regularization to construct the inversion objective function,building upon TV regularization,and subsequently employs the alternating direction multiplier method for solving.This approach mitigates the step effect stemming from total variation in seismic inversion,thereby facilitating the reconstruction of sharp interfaces of geophysical parameters while smoothing background variations.Simultaneously,replacing integer-order differences with fractional-order differences bolsters the correlation among seismic data and diminishes the scattering effect caused by integer-order differences in seismic inversion.The outcomes of model tests validate the efficacy of this method,highlighting its ability to enhance the overall accuracy of the inversion process. 展开更多
关键词 Full waveform inversion Anisotropic total p-variation Fractional-order differences Sparse regularization
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Deterministic Convergence Analysis for GRU Networks via Smoothing Regularization
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作者 Qian Zhu Qian Kang +2 位作者 Tao Xu Dengxiu Yu Zhen Wang 《Computers, Materials & Continua》 2025年第5期1855-1879,共25页
In this study,we present a deterministic convergence analysis of Gated Recurrent Unit(GRU)networks enhanced by a smoothing L_(1)regularization technique.While GRU architectures effectively mitigate gradient vanishing/... In this study,we present a deterministic convergence analysis of Gated Recurrent Unit(GRU)networks enhanced by a smoothing L_(1)regularization technique.While GRU architectures effectively mitigate gradient vanishing/exploding issues in sequential modeling,they remain prone to overfitting,particularly under noisy or limited training data.Traditional L_(1)regularization,despite enforcing sparsity and accelerating optimization,introduces non-differentiable points in the error function,leading to oscillations during training.To address this,we propose a novel smoothing L_(1)regularization framework that replaces the non-differentiable absolute function with a quadratic approximation,ensuring gradient continuity and stabilizing the optimization landscape.Theoretically,we rigorously establish threekey properties of the resulting smoothing L_(1)-regularizedGRU(SL_(1)-GRU)model:(1)monotonic decrease of the error function across iterations,(2)weak convergence characterized by vanishing gradients as iterations approach infinity,and(3)strong convergence of network weights to fixed points under finite conditions.Comprehensive experiments on benchmark datasets-spanning function approximation,classification(KDD Cup 1999 Data,MNIST),and regression tasks(Boston Housing,Energy Efficiency)-demonstrate SL_(1)-GRUs superiority over baseline models(RNN,LSTM,GRU,L_(1)-GRU,L2-GRU).Empirical results reveal that SL_(1)-GRU achieves 1.0%-2.4%higher test accuracy in classification,7.8%-15.4%lower mean squared error in regression compared to unregularized GRU,while reducing training time by 8.7%-20.1%.These outcomes validate the method’s efficacy in balancing computational efficiency and generalization capability,and they strongly corroborate the theoretical calculations.The proposed framework not only resolves the non-differentiability challenge of L_(1)regularization but also provides a theoretical foundation for convergence guarantees in recurrent neural network training. 展开更多
关键词 Gated recurrent unit regularization convergence
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甲状腺结节、乳腺增生和子宫肌瘤三病的相关性及患病规律:基于真实世界数据的研究 被引量:1
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作者 李春晓 张莹莹 +3 位作者 凌霄 杨玉晴 张业 金艳涛 《中华中医药学刊》 北大核心 2026年第1期7-12,共6页
目的旨在探究甲状腺结节(thyroid nodules,TN)、乳腺增生(hyperplasia of mammary gland,HMG)和子宫肌瘤(uterine leiomyomas,UL)三种疾病之间的相互关联性及其患病规律,为临床诊疗方案和合理用药提供科学依据。方法回顾性分析了河南中... 目的旨在探究甲状腺结节(thyroid nodules,TN)、乳腺增生(hyperplasia of mammary gland,HMG)和子宫肌瘤(uterine leiomyomas,UL)三种疾病之间的相互关联性及其患病规律,为临床诊疗方案和合理用药提供科学依据。方法回顾性分析了河南中医药大学第一附属医院体检中心2011年10月19日—2018年12月19日进行甲状腺、乳房、子宫超声检查的女性体检者的电子健康记录。根据检出结果,将单独检出任一疾病、任意两种疾病共发及三病并发的病例纳入病例组,未检出任何疾病的个体纳入对照组。通过SPSS Statistics 22.0软件运用Cochran-Mantel-Haenszel检验及描述性统计方法,分析三种疾病之间的相关性及患病规律。结果共纳入符合研究条件的病例5252例,其中病例组2902例。相关性分析显示,任意两病的共发均有显著的正向相关性。其中TN与HMG在45~59岁年龄组(r=0.106,P<0.001)、TN与UL在18~44岁年龄组(r=0.122,P<0.001)、HMG和UL在45~59岁年龄组(r=0.157,P<0.001)的相关性最为显著。描述性统计分析表明,三病或任意两病的并发主要集中在45~59岁年龄段。三种疾病患者的中医体质主要为痰湿质和阳虚质,血压、血脂及血糖水平大多正常,但与对照组相比存在显著差异(P<0.001)。实验室检查结果显示,血常规、肝功能和肾功能指标均处于正常范围内,但与对照组相比存在显著差异(P<0.001)。结论基于真实世界数据的研究结果显示,甲状腺结节、乳腺增生和子宫肌瘤三种疾病间存在显著的正向相关性,且在年龄分布、中医体质、血压、血糖、血脂及实验室检验指标方面与正常组相比均有显著差异,为这三种疾病的早期发现、预防和治疗提供了重要依据。 展开更多
关键词 甲状腺结节 乳腺增生 子宫肌瘤 数据挖掘 真实世界研究 患病规律
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融合DepGraph偏移正则化的绝缘子多缺陷检测轻量化算法
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作者 亢洁 常琦 +2 位作者 王勍 刘伟峰 刘文波 《计算机工程与应用》 北大核心 2026年第1期328-338,共11页
针对绝缘子缺陷检测算法具有较大的参数规模和计算量导致难以部署在边缘设备,模型剪枝后难以获得正确连接,且过度稀疏化训练导致模型精度大幅度下降等问题,提出一种基于DepGraph偏移正则化的绝缘子多缺陷检测轻量化算法。通过依赖图(Dep... 针对绝缘子缺陷检测算法具有较大的参数规模和计算量导致难以部署在边缘设备,模型剪枝后难以获得正确连接,且过度稀疏化训练导致模型精度大幅度下降等问题,提出一种基于DepGraph偏移正则化的绝缘子多缺陷检测轻量化算法。通过依赖图(DepGraph)对改进后YOLOv7网络建立连接关系模型,再添加偏移正则化稀疏约束对其进行组级的稀疏训练,删除冗余的连接,得到参数规模和计算量更小的轻量型检测算法。将提出的模型压缩算法应用到绝缘子多缺陷检测任务中,实验结果表明,剪枝后模型相较于未剪枝模型的参数规模和计算量分别下降65.25%和65.98%,而平均准确率仅减少1.1个百分点,验证了DepGraph偏移正则化方案在绝缘子多缺陷检测任务中的有效性;在CIFAR-10数据集上进行实验,实验结果表明,在加速比为2.88时,所提算法仍可以保持93.69%的分类精度。使用TensorRT对该算法进行推理加速,并在Jetson Orin Nano平台上部署,经过TensorRT优化后模型的检测速度达到了35.24帧/s,符合在移动设备上部署的需求。 展开更多
关键词 绝缘子 缺陷检测 轻量化 DepGraph 偏移正则化
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玉―豆和麦―豆轮作对大豆田杂草发生规律的影响
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作者 王宇 王金生 +6 位作者 王晓曦 马力 王克勤 王春 刘兴龙 吴俊江 李沐恺 《作物杂志》 北大核心 2026年第1期175-181,共7页
为精准制定玉米―大豆(玉―豆)和小麦―大豆(麦―豆)轮作种植模式下大豆田杂草的防控措施,调查了2种轮作模式下大豆田杂草发生种类和数量。结果表明,在2年试验中,玉―豆轮作模式下的杂草发生量分别是麦―豆轮作模式的1.89倍和1.49倍。... 为精准制定玉米―大豆(玉―豆)和小麦―大豆(麦―豆)轮作种植模式下大豆田杂草的防控措施,调查了2种轮作模式下大豆田杂草发生种类和数量。结果表明,在2年试验中,玉―豆轮作模式下的杂草发生量分别是麦―豆轮作模式的1.89倍和1.49倍。玉―豆轮作模式下共11种杂草在2年均有发生,包括2种禾本科杂草和9种阔叶杂草,优势种杂草为禾本科杂草稗草和阔叶杂草藜、苘麻,亚优势种杂草为禾本科杂草野黍和阔叶杂草反枝苋、龙葵。麦―豆轮作模式下2年有8种杂草共同发生,包括禾本科杂草2种和阔叶杂草6种,优势种杂草为禾本科杂草稗草和阔叶杂草藜、苘麻,亚优势种杂草为阔叶杂草龙葵。玉―豆轮作模式下杂草发生量有2个高峰期,分别是在5月末到6月中旬和6月末到7月上旬,第1个高峰期的发生量大于第2个高峰期;而麦―豆轮作模式下则只有1个杂草发生高峰期,主要集中在6月上中旬。 展开更多
关键词 大豆田 轮作 杂草种类 优势种杂草 杂草发生规律
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一种表面热流辨识结果的不确定度分析方法
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作者 周宇 邵元培 +1 位作者 钱炜祺 郑凤麒 《实验流体力学》 北大核心 2026年第1期127-134,共8页
利用热防护层内部温度时序数据辨识表面热流,是获取高速飞行器表面热环境的重要手段。分析及量化辨识结果的不确定度,可为试验数据有效性提供量化标准,支撑热环境“极端工况”安全评估。表面热流辨识是一种典型的不适定问题,测量噪声中... 利用热防护层内部温度时序数据辨识表面热流,是获取高速飞行器表面热环境的重要手段。分析及量化辨识结果的不确定度,可为试验数据有效性提供量化标准,支撑热环境“极端工况”安全评估。表面热流辨识是一种典型的不适定问题,测量噪声中的高频成分会破坏解的稳定性,需要通过正则化获得稳定解。虽然正则化降低了估计结果的不确定性,但给不确定度分析制造了障碍。为此,将正则化看作低通滤波器,将辨识结果转换到频域来分析辨识结果的不确定度。最后,以典型飞行器温度测量组件的表面热流辨识为例,分析了不确定度来源,并利用蒙特卡洛方法验证了不确定度分析方法的有效性。 展开更多
关键词 表面热流 辨识 不适定性 正则化 不确定度 低通滤波器
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基于非零水平集保凸算法的左心室MRI分割
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作者 李季 刘艾汶 秦柳 《山东大学学报(理学版)》 北大核心 2025年第7期32-47,共16页
心脏左心室分割临床应用要求是分割的左心室保持凸形且包含左心室腔、小梁和乳头肌,提出一个包含改进距离正则项和非零水平集保凸项的心脏核磁共振成像分割模型,其利用水平集轮廓的曲率来保持凸性,从而使轮廓最终演化为凸形。使用ACDC M... 心脏左心室分割临床应用要求是分割的左心室保持凸形且包含左心室腔、小梁和乳头肌,提出一个包含改进距离正则项和非零水平集保凸项的心脏核磁共振成像分割模型,其利用水平集轮廓的曲率来保持凸性,从而使轮廓最终演化为凸形。使用ACDC MICCAI 2017数据集进行模型评估,该模型在心脏舒张末期和收缩末期阶段的平均Dice系数分别为0.961和0.936,平均豪斯多夫距离分别为4.89和5.79。同时该模型无需对训练数据进行人工标注和学习,分割精度和鲁棒性均可以达到与基于深度学习的左心室分割模型相同的分割性能。 展开更多
关键词 非零水平集 保凸 水平集方法 左心室分割 距离正则化 双阱势函数
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基于分裂Bregman迭代的全变分去噪算法在隧道衬砌探地雷达F-K偏移中的应用
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作者 李峰 徐正宣 +2 位作者 巨莉 伊小娟 王栋 《隧道建设(中英文)》 北大核心 2026年第2期430-436,共7页
为解决隧道衬砌探地雷达F-K偏移剖面中存在偏移噪声的问题,提高实际探地雷达检测剖面的分辨率与准确度,构建一种基于分裂Bregman迭代的全变分正则化算法。首先,根据偏移含噪剖面构建全变分正则化目标函数;然后,通过Bregman距离近似表述... 为解决隧道衬砌探地雷达F-K偏移剖面中存在偏移噪声的问题,提高实际探地雷达检测剖面的分辨率与准确度,构建一种基于分裂Bregman迭代的全变分正则化算法。首先,根据偏移含噪剖面构建全变分正则化目标函数;然后,通过Bregman距离近似表述正则化项,使正则化项与数据不拟合项分离,将目标函数的求解转化为最优化问题;最后,通过Gauss-Seidel迭代计算解决该最优化问题,利用全变分范数的最小化特性实现偏移剖面的噪声压制,并以隧道衬砌钢筋结构模型算例和叙古高速公路隧道衬砌实际检测数据验证该算法的有效性和实用性。结果表明:1)该算法能有效压制由高频干扰引发的弧形干扰与伪影,同时可以保护图像中的边界信息;2)该算法噪声压制效果主要与去噪参数和收敛阈值有关,在实际数据处理中可根据计算效果与计算成本综合选取;3)该算法可有效压制剖面中的偏移噪声,提升探地雷达剖面信噪比与准确度,且对实际数据有良好的适应性。 展开更多
关键词 隧道衬砌 探地雷达 分裂Bregman迭代 全变分正则化 去噪
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基于协同训练的直肠肿瘤MRI半监督分割方法
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作者 李亚楠 赵雅坤 +1 位作者 金鑫 王明甲 《青岛科技大学学报(自然科学版)》 2025年第3期143-151,共9页
直肠肿瘤病灶区域的精确分割可以为肿瘤的临床治疗和预后监测提供重要依据。直肠肿瘤MRI图像结构比较复杂,标签数据获取困难且成本高,为了利用大量无标记数据,本研究采用半监督图像分割方法。针对直肠癌目标靶区在MRI上呈现大小、形状... 直肠肿瘤病灶区域的精确分割可以为肿瘤的临床治疗和预后监测提供重要依据。直肠肿瘤MRI图像结构比较复杂,标签数据获取困难且成本高,为了利用大量无标记数据,本研究采用半监督图像分割方法。针对直肠癌目标靶区在MRI上呈现大小、形状、纹理及边界清晰度存在个体差异性的问题,本研究在U-Net网络的基础上设计了一种新型分割网络DCCBAM-UNet,并结合使用基于协同训练的半监督方法开展直肠肿瘤MRI的分割研究。该方法通过对双学生-教师模型设置不同初始化的方式进行一致性约束,以集成方法获取高质量的伪标签,引入蒙特卡罗Dropout方法度量伪标签的不确定性,减轻低质量伪标签对分割性能的影响。在使用30%的训练数据下,该模型的DICE达到了0.9234,Jaccard达到了0.6542,HD达到了12.035。实验结果表明,该模型在医学图像分割的有效性和泛化性上有一定的性能提升,能有效解决数据集数量少、病灶区域分割难度大的问题。 展开更多
关键词 半监督学习 直肠肿瘤分割 协同训练 伪标签 一致性正则化
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非平整岛礁对波浪传播变形与增水影响的试验研究
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作者 王超 屈科 +2 位作者 王旭 李玮 陈佳莹 《海洋科学进展》 北大核心 2026年第1期173-184,共12页
广泛分布于热带和亚热带海域的珊瑚礁一般具有非平整的礁坪地形,礁坪地形的变化会显著影响入射波浪在岛礁上的传播演变特性。然而,以往研究尚未系统探讨礁坪地形突变对规则波岛礁水动力特性的影响。本文通过开展波浪水槽实验,研究非平... 广泛分布于热带和亚热带海域的珊瑚礁一般具有非平整的礁坪地形,礁坪地形的变化会显著影响入射波浪在岛礁上的传播演变特性。然而,以往研究尚未系统探讨礁坪地形突变对规则波岛礁水动力特性的影响。本文通过开展波浪水槽实验,研究非平整岛礁地形规则波浪的水动力特性和非线性特性,进而系统分析入射波高、波浪周期和礁坪水深三种不同入射波浪要素对波浪传播变形与增水的影响。研究结果表明,非平整礁坪增强了波浪的非线性变化,在礁坪台阶附近不对称度、偏度和厄塞尔数均达到峰值,促进了波能从主频波向高次谐波的转移;波浪在第二礁坪上破碎耗散的能量主要来自主频波,岸线附近透射波成分中二次谐波与主频波能量相当。此外,入射波高增大或礁坪水深减小都会致使波浪在礁坪台阶附近的破碎强度增加,从而在第二礁坪上波浪的增水值增加。当增大波浪周期时,多重波浪反射作用下会在第一礁坪上形成驻波,礁坪台阶附近更多波能向高次谐波转移,第二礁坪上波浪增水值呈现出非线性变化。 展开更多
关键词 规则波 珊瑚礁 地形突变 波浪破碎 波浪增水 波浪非线性
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基于改进Chahine算法的水下气泡激光衍射分布反演技术
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作者 张宇 种慧琪 +2 位作者 张进 吴羽 芮小博 《红外与激光工程》 北大核心 2026年第1期212-224,共13页
舰船在航行过程中会产生一条绵延数公里的尾流带,不同排水量、航行速度的舰船产生的尾流气泡大小分布不同,因此可以用于舰船的识别与追踪。针对传统光散射反演方法存在病态性及噪声敏感问题,提出一种基于自适应正则化算子的改进Chahine... 舰船在航行过程中会产生一条绵延数公里的尾流带,不同排水量、航行速度的舰船产生的尾流气泡大小分布不同,因此可以用于舰船的识别与追踪。针对传统光散射反演方法存在病态性及噪声敏感问题,提出一种基于自适应正则化算子的改进Chahine算法,通过构造自适应正则化矩阵,保留较大奇异值并修正较小奇异值,以提升气泡分布反演的稳定性和抗噪性。搭建了一套用于气泡分布反演的水下激光衍射装置,实验采用气泡机模拟舰船尾流气泡幕。结合仿真与实验验证方法有效性。仿真结果表明:在高噪声干扰下,文中算法对正态分布和Rosin–Rammler分布气泡的反演相对均方根误差分别为7.95%和9.70%,具有相对较好的反演效果;实验结果表明:改进算法对标准颗粒反演误差为2.39%,误差较小,证明了激光衍射装置的有效性,通过对气泡群进行反演,证明了改进算法的可行性。改进算法通过自适应正则化策略有效抑制噪声干扰,提高了反演结果的稳定性,为高噪声环境下舰船尾流气泡分布反演提供了可靠的解决方案。 展开更多
关键词 水下探测 改进Chahine算法 自适应正则化 激光衍射 气泡分布
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中国岩浆型铁矿的矿产地数量-规模-品位结构及时空分布
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作者 李厚民 李立兴 +2 位作者 李小赛 吴玄 孟洁 《地质学报》 北大核心 2026年第1期1-10,共10页
岩浆型铁矿赋存于镁铁—超镁铁质岩体中,是我国仅次于沉积变质型铁矿的重要铁矿床类型,并且共伴生有钛、钒、钴、镍、磷等资源。截至目前,我国已发现岩浆型铁矿产地231个,其中超大型铁矿床4个、大型铁矿床17个、中型铁矿床49个。统计表... 岩浆型铁矿赋存于镁铁—超镁铁质岩体中,是我国仅次于沉积变质型铁矿的重要铁矿床类型,并且共伴生有钛、钒、钴、镍、磷等资源。截至目前,我国已发现岩浆型铁矿产地231个,其中超大型铁矿床4个、大型铁矿床17个、中型铁矿床49个。统计表明,岩浆型铁矿的矿石品位总体较低:TFe(全铁)品位25%~45%的矿产地数量占比53%,铁矿石量占比64%;TFe品位25%~20%的铁矿产地占比16%,矿石量占比24%;TFe品位低于20%的铁矿产地占比27%,矿石量占比12%。岩浆型铁矿床中虽然超大型规模者仅有4个,但其铁矿石量占比却达72%;大型铁矿床数占比9%,铁矿石量占比19%,表明大型、超大型矿床在岩浆型铁矿中占有举足轻重的地位。在时间分布特征上,岩浆型铁矿从太古宙到中生代均有分布,但以二叠纪攀枝花式铁矿具有绝对优势地位,其次为中元古代的大庙式铁矿。在空间分布特征上,全国有22个省(区市)发现有岩浆型铁矿的矿产地,但数量及矿石量集中于四川攀西地区的Ⅲ-76康滇隆起Fe-Cu-V-Ti-Sn-Ni-REE-Au-蓝石棉-盐类成矿带,其次为河北承德地区的Ⅲ-57华北陆块北缘东段Fe-Cu-Mo-Pb-Zn-Ag-Mn-U-磷-煤-膨润土成矿带,另外陕西安康—汉中、山东沂水—莒县、新疆塔里木盆地及邻区也较重要。岩浆型铁矿成矿均与拉张背景下的重大构造-岩浆事件有关,如攀枝花式铁矿与二叠纪峨眉地幔柱有关,大庙式铁矿与1.8~1.7 Ga华北克拉通的超大陆裂解事件有关等。 展开更多
关键词 钒钛磁铁矿 岩浆型 矿产地数量 矿石品位 时空分布规律
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