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Preliminary study on a quantification method and standardization for aquatic microbial loads based on microbial diversity absolute quantitative sequencing
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作者 Wen Li Jing Libin +4 位作者 Li Xiawei Lu Jing Jin Haowei Yang Yongqi Li Xueling 《China Standardization》 2026年第1期68-73,共6页
This study establishes and validates a method for the precise quantification of aquatic microbial loads using microbial diversity absolute quantitative sequencing.By adding synthetic spike-in DNA to water samples from... This study establishes and validates a method for the precise quantification of aquatic microbial loads using microbial diversity absolute quantitative sequencing.By adding synthetic spike-in DNA to water samples from the Dahei River prior to DNA extraction and 16S rRNA gene sequencing,it generates standard curves to convert sequencing data into absolute microbial copy numbers.The method,which is proved highly accurate(R^(2)>0.99),reveals a clear contrast between the river sites:the upstream community has not only a significantly higher total microbial load but also a completely different makeup of species compared to the downstream site.This approach effectively overcomes the limitations of relative abundance analysis,providing a powerful tool for environmental monitoring,and proposes key steps for future standardization to ensure data comparability and integration. 展开更多
关键词 absolute quantification microbial load 16S rRNA sequencing spike-in STANDARDIZATION aquatic microbes
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Deep Learning-Based Structural Displacement Identification and Quantification under Target Feature Loss
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作者 Lishuai Zhu Guangcai Zhang +4 位作者 Qun Xie Zhen Peng Li Ai Ruijun Liang Taochun Yang 《Structural Durability & Health Monitoring》 2026年第2期57-77,共21页
Structural displacement monitoring faces significant challenges under complex environmental conditions due to the loss or degradation of target features,making it difficult for traditional methods to ensure high accur... Structural displacement monitoring faces significant challenges under complex environmental conditions due to the loss or degradation of target features,making it difficult for traditional methods to ensure high accuracy and robustness.Therefore,this study proposes a structural displacement identification and quantification method that integrates YOLOv8n with an improved edge-orientation gradient-based template matching algorithm.By combining deep learning techniques with traditional template matching methods,the accuracy and robustness of monitoring are enhanced under adverse conditions such as noise and extremely low illumination.Specifically,in the edge-orientation gradient matching stage,the Canny-Devernay sub-pixel edge detection technique and an improved ellipse-fitting method are employed for sub-pixel edge extraction,and a five-level Gaussian pyramid structure is introduced to accelerate the matching speed.Experimental results show that the proposed method achieves high-precision displacement monitoring under sufficient illumination,and it maintains stable target localization and displacement quantification performance under conditions of noise interference and extremely low illumination.Notably,under salt-and-pepper noise interference,although YOLOv8n maintains a high level of localization confidence,the accuracy of gradient matching deteriorates,resulting in a root-mean-square error(RMSE)of 0.035 mm.This finding reveals the differential impact of various noise types on different stages of the algorithm.The proposed method offers a novel technological approach for precise structural displacement monitoring in complex environments. 展开更多
关键词 Structural displacement quantification complex environments edge detection ellipse fitting template matching
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Sequential search-based Latin hypercube sampling scheme for digital twin uncertainty quantification with application in EHA 被引量:1
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作者 Dong LIU Shaoping WANG +1 位作者 Jian SHI Di LIU 《Chinese Journal of Aeronautics》 2025年第4期176-192,共17页
For uncertainty quantification of complex models with high-dimensional,nonlinear,multi-component coupling like digital twins,traditional statistical sampling methods,such as random sampling and Latin hypercube samplin... For uncertainty quantification of complex models with high-dimensional,nonlinear,multi-component coupling like digital twins,traditional statistical sampling methods,such as random sampling and Latin hypercube sampling,require a large number of samples,which entails huge computational costs.Therefore,how to construct a small-size sample space has been a hot issue of interest for researchers.To this end,this paper proposes a sequential search-based Latin hypercube sampling scheme to generate efficient and accurate samples for uncertainty quantification.First,the sampling range of the samples is formed by carving the polymorphic uncertainty based on theoretical analysis.Then,the optimal Latin hypercube design is selected using the Latin hypercube sampling method combined with the"space filling"criterion.Finally,the sample selection function is established,and the next most informative sample is optimally selected to obtain the sequential test sample.Compared with the classical sampling method,the generated samples can retain more information on the basis of sparsity.A series of numerical experiments are conducted to demonstrate the superiority of the proposed sequential search-based Latin hypercube sampling scheme,which is a way to provide reliable uncertainty quantification results with small sample sizes. 展开更多
关键词 Digital Twin(DT) Genetic algorithms(GA) Optimal Latin Hypercube Design(Opt LHD) Sequential test Uncertainty quantification(UQ) EHA
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A Gel-Free Budget-Friendly Approach to GFP-Tagged Viruses Quantification in Plant Samples
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作者 Rohith Grandhi Mélodie B.Plourde +1 位作者 Aditi Balasubramani Hugo Germain 《Phyton-International Journal of Experimental Botany》 2025年第5期1497-1504,共8页
Viral diseases are an important threat to crop yield,as they are responsible for losses greater than US$30 billion annually.Thus,understanding the dynamics of virus propagation within plant cells is essential for devi... Viral diseases are an important threat to crop yield,as they are responsible for losses greater than US$30 billion annually.Thus,understanding the dynamics of virus propagation within plant cells is essential for devising effective control strategies.However,viruses are complex to propagate and quantify.Existing methodologies for viral quantification tend to be expensive and time-consuming.Here,we present a rapid cost-effective approach to quantify viral propagation using an engineered virus expressing a fluorescent reporter.Using a microplate reader,we measured viral protein levels and we validated our findings through comparison by western blot analysis of viral coat protein,the most common approach to quantify viral titer.Our proposed methodology provides a practical and accessible approach to studying virus-host interactions and could contribute to enhancing our understanding of plant virology. 展开更多
关键词 Microplate reader CP-PlAMV viruses plant viral quantification green fluorescent protein western blot quantification Nicotiana benthamiana Arabidopsis thaliana Pearson’s correlation
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Quantification of Streptococcus salivarius using the digital polymerase chain reaction as a liver fibrosis marker
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作者 Shuichiro Iwasaki Akira Také +8 位作者 Haruki Uojima Kazue Horio Yoshihiko Sakaguchi Kazuyoshi Gotoh Takashi Satoh Hisashi Hidaka Yasuhito Tanaka Shunji Hayashi Chika Kusano 《World Journal of Hepatology》 2025年第4期53-66,共14页
BACKGROUND The Streptococcus salivarius(S.salivarius)group,which produces the enzyme urease has been identified as a potential contributor to ammonia production in the gut.Researchers have reported that patients with ... BACKGROUND The Streptococcus salivarius(S.salivarius)group,which produces the enzyme urease has been identified as a potential contributor to ammonia production in the gut.Researchers have reported that patients with minimal HE had an increased abundance of the S.salivarius group,which is a specific change in the gut microbiota that distinguishes them from healthy individuals.The correlation between the aggregation of specific bacterial species and fibrosis progression in chronic liver disease(CLD)is yet to be fully elucidated.AIM To quantify S.salivarius using digital PCR(dPCR)as a liver fibrosis marker of CLD.METHODS This study retrospectively analysed 52 patients with CLD.To quantify S.salivarius in patients with CLD using dPCR,we evaluated the specificity and sensitivity of S.salivarius bacterial load using dPCR for a type strain.Next,we evaluated the clinical usefulness of dPCR for S.salivarius load quantification for detecting liver fibrosis in patients with CLD.The liver fibrosis stage was categorized into mild and advanced fibrosis based on pathological findings.RESULTS The dPCR assay revealed that S.salivarius was highly positive for the tnpA gene.The lower limit of quantification for dPCR using the tnpA gene with a 1μL template comprising 1.28×102 CFU/mL was 4.3 copies.After considering the detection range in dPCR,we adjusted the extracted DNA concentration to 5.0×10-4 ng/μL from 200 mg stool samples.The median bacterial loads of S.salivarius in stool sample from patients with mild and advanced fibrosis were 1.9 and 7.4 copies/μL,respectively.The quantification of S.salivarius load was observed more frequently in patients with advanced fibrosis than in those with mild fibrosis(P=0.032).CONCLUSION Quantifying of S.salivarius load using digital PCR is a useful biomarker for liver fibrosis in patients with CLD. 展开更多
关键词 Chronic liver disease Streptococcus salivarius Digital PCR Liver fibrosis Liver cirrhosis quantification
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Fe^(3+) ion quantification with reusable bioinspired nanopores
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作者 Yanqiong Wang Yaqi Hou +1 位作者 Fengwei Huo Xu Hou 《Chinese Chemical Letters》 2025年第2期179-184,共6页
Excessive Fe^(3+) ion concentrations in wastewater pose a long-standing threat to human health.Achieving low-cost,high-efficiency quantification of Fe^(3+) ion concentration in unknown solutions can guide environmenta... Excessive Fe^(3+) ion concentrations in wastewater pose a long-standing threat to human health.Achieving low-cost,high-efficiency quantification of Fe^(3+) ion concentration in unknown solutions can guide environmental management decisions and optimize water treatment processes.In this study,by leveraging the rapid,real-time detection capabilities of nanopores and the specific chemical binding affinity of tannic acid to Fe^(3+),a linear relationship between the ion current and Fe^(3+) ion concentration was established.Utilizing this linear relationship,quantification of Fe^(3+) ion concentration in unknown solutions was achieved.Furthermore,ethylenediaminetetraacetic acid disodium salt was employed to displace Fe^(3+) from the nanopores,allowing them to be restored to their initial conditions and reused for Fe^(3+) ion quantification.The reusable bioinspired nanopores remain functional over 330 days of storage.This recycling capability and the long-term stability of the nanopores contribute to a significant reduction in costs.This study provides a strategy for the quantification of unknown Fe^(3+) concentration using nanopores,with potential applications in environmental assessment,health monitoring,and so forth. 展开更多
关键词 Bioinspired nanopores Fe^(3+)ion quantification Chemical binding affinity Tannic acid REUSABILITY
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Uncertainty Quantification of Dynamic Stall Aerodynamics for Large Mach Number Flow around Pitching Airfoils
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作者 Yizhe Han Guangjing Huang +2 位作者 Fei Xiao Zhiyin Huang Yuting Dai 《Fluid Dynamics & Materials Processing》 2025年第7期1657-1671,共15页
During high-speed forward flight,helicopter rotor blades operate across a wide range of Reynolds and Mach numbers.Under such conditions,their aerodynamic performance is significantly influenced by dynamic stall—a com... During high-speed forward flight,helicopter rotor blades operate across a wide range of Reynolds and Mach numbers.Under such conditions,their aerodynamic performance is significantly influenced by dynamic stall—a complex,unsteady flow phenomenon highly sensitive to inlet conditions such asMach and Reynolds numbers.The key features of three-dimensional blade stall can be effectively represented by the dynamic stall behavior of a pitching airfoil.In this study,we conduct an uncertainty quantification analysis of dynamic stall aerodynamics in high-Mach-number flows over pitching airfoils,accounting for uncertainties in inlet parameters.A computational fluid dynamics(CFD)model based on the compressible unsteady Reynolds-averagedNavier–Stokes(URANS)equations,coupledwith sliding mesh techniques,is developed to simulate the unsteady aerodynamic behavior and associated flow fields.To efficiently capture the aerodynamic responses while maintaining high accuracy,a multi-fidelity Co-Kriging surrogate model is constructed.This model integrates the precision of high-fidelity wind tunnel experiments with the computational efficiency of lower-fidelity URANS simulations.Its accuracy is validated through direct comparison with experimental data.Building upon this surrogate model,we employ interval analysis and the Sobol sensitivity method to quantify the uncertainty and parameter sensitivity of the unsteady aerodynamic forces resulting frominlet condition variability.Both the inlet Mach number and Reynolds number are treated as uncertain inputs,modeled using interval representations.Our results demonstrate that variations inMach number contribute far more significantly to aerodynamic uncertainty than those in Reynolds number.Moreover,the presence of dynamic stall vortices markedly amplifies the aerodynamic sensitivity to Mach number fluctuations. 展开更多
关键词 Dynamic stall uncertainty quantification multi-fidelity surrogate modeling sensitivity analysis
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Research on Quantification Mechanism of Data Source Reliability Based on Trust Evaluation
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作者 Gaoshang Lu Fa Fu Zixiang Tang 《Computers, Materials & Continua》 2025年第6期4239-4256,共18页
In the data transaction process within a data asset trading platform,quantifying the trustworthiness of data source nodes is challenging due to their numerous attributes and complex structures.To address this issue,a ... In the data transaction process within a data asset trading platform,quantifying the trustworthiness of data source nodes is challenging due to their numerous attributes and complex structures.To address this issue,a distributed data source trust assessment management framework,a trust quantification model,and a dynamic adjustment mechanism are proposed.Themodel integrates the Analytic Hierarchy Process(AHP)and Dempster-Shafer(D-S)evidence theory to determine attribute weights and calculate direct trust values,while the PageRank algorithm is employed to derive indirect trust values.Thedirect and indirect trust values are then combined to compute the comprehensive trust value of the data source.Furthermore,a dynamic adjustment mechanism is introduced to continuously update the comprehensive trust value based on historical assessment data.By leveraging the collaborative efforts of multiple nodes in the distributed network,the proposed framework enables a comprehensive,dynamic,and objective evaluation of data source trustworthiness.Extensive experimental analyses demonstrate that the trust quantification model effectively handles large-scale data source trust assessments,exhibiting both strong trust differentiation capability and high robustness. 展开更多
关键词 Trust evaluation data source reliability distributed network quantification mechanism
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MultiJSQ:Direct joint segmentation and quantification of left ventricle with deep multitask-derived regression network
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作者 Xiuquan Du Zheng Pei +3 位作者 Ying Liu Xinzhi Cao Lei Li Shuo Li 《CAAI Transactions on Intelligence Technology》 2025年第1期175-192,共18页
Quantitative analysis of clinical function parameters from MRI images is crucial for diagnosing and assessing cardiovascular disease.However,the manual calculation of these parameters is challenging due to the high va... Quantitative analysis of clinical function parameters from MRI images is crucial for diagnosing and assessing cardiovascular disease.However,the manual calculation of these parameters is challenging due to the high variability among patients and the time-consuming nature of the process.In this study,the authors introduce a framework named MultiJSQ,comprising the feature presentation network(FRN)and the indicator prediction network(IEN),which is designed for simultaneous joint segmentation and quantification.The FRN is tailored for representing global image features,facilitating the direct acquisition of left ventricle(LV)contour images through pixel classification.Additionally,the IEN incorporates specifically designed modules to extract relevant clinical indices.The authors’method considers the interdependence of different tasks,demonstrating the validity of these relationships and yielding favourable results.Through extensive experiments on cardiac MR images from 145 patients,MultiJSQ achieves impressive outcomes,with low mean absolute errors of 124 mm^(2),1.72 mm,and 1.21 mm for areas,dimensions,and regional wall thicknesses,respectively,along with a Dice metric score of 0.908.The experimental findings underscore the excellent performance of our framework in LV segmentation and quantification,highlighting its promising clinical application prospects. 展开更多
关键词 global image features joint segmentation and quantification left ventricle(LV) multitask-derived regression network
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Quantification and reduction of uncertainty in aerodynamic performance of GAN-generated airfoil shapes using MC dropouts
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作者 Kazuo Yonekura Ryuto Aoki Katsuyuki Suzuki 《Theoretical & Applied Mechanics Letters》 2025年第4期372-377,共6页
Generative adversarial network(GAN)models are widely used in mechanical designs.The aim in the airfoil shape design is to obtain shapes that exhibits the required aerodynamic performance,and conditional GAN is used fo... Generative adversarial network(GAN)models are widely used in mechanical designs.The aim in the airfoil shape design is to obtain shapes that exhibits the required aerodynamic performance,and conditional GAN is used for that aim.However,the output of GAN contains uncertainties.Additionally,the uncertainties of labels have not been quantified.This paper proposes an uncertainty quantification method to estimate the uncertainty of labels using Monte Carlo dropout.In addition,an uncertainty reduction method is proposed based on imbalanced training.The proposed method was evaluated for the airfoil generation task.The results indicated that the uncertainty was appropriately quantified and successfully reduced. 展开更多
关键词 Uncertainty quantification GAN Airfoil shapegeneration
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A rapid tool for quantification of latent infection of wheat leaves by powdery mildew
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作者 Aolin Wang Ru Jiang +9 位作者 Meihui Zhang Hudie Shao Fei Xu Kouhan Liu Haifeng Gao Jieru Fan Wei Liu Xiaoping Hu Yilin Zhou Xiangming Xu 《Journal of Integrative Agriculture》 2025年第12期4690-4702,共13页
Wheat powdery mildew caused by Blumeria graminis f.sp.tritici(Bgt)is an important disease worldwide.Detection of latent infection of leaves by the pathogen in late autumn is valuable for estimating the inoculum potent... Wheat powdery mildew caused by Blumeria graminis f.sp.tritici(Bgt)is an important disease worldwide.Detection of latent infection of leaves by the pathogen in late autumn is valuable for estimating the inoculum potential to assess disease risks in the spring.We developed a new tool for rapid detection and quantification of latent infection of seedlings by the pathogen.The method was based on recombinase polymerase amplification(RPA)coupled with an end-point detection via lateral flow device(LFD).The limit of detection is 100 agμL^(-1)of Bgt DNA,without noticeable interference from either other common wheat pathogens or wheat material(Triticum aestivum).It was evaluated on wheat seedlings for this accuracy and sensitivity in detecting latent infection of Bgt.We further extended this RPALFD assay to estimate the level of latent infection by Bgt based on imaging analysis.There was a strong correlation between the image-based and real-time PCR assay estimates of Bgt DNA.The present results suggested that this new tool can provide rapid and accurate quantification of Bgt in latently infected leaves and can be further development as an on-site monitoring tool. 展开更多
关键词 Blumeria graminis f.sp.tritici(Bgt) recombinase polymerase amplification(RPA) lateral flow device(LFD) image-based quantification disease monitoring
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南亚热带牛姆林群落常见种和稀有种的物种组成差异
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作者 江蓝 杨晶晶 +7 位作者 韦鑫 朱静 刘金福 郑晨成 徐道炜 郭相亿 张朝鹏 何中声 《应用与环境生物学报》 北大核心 2026年第1期39-47,共9页
局域群落由一系列种群数量与分布范围不一的物种组成,探究群落常见种和稀有种的物种组成差异对生物多样性保护与维持具有重要意义.以南亚热带牛姆林天然林为研究对象,依据模糊聚类算法划分局域群落常见种和稀有种,进而比较常见种和稀有... 局域群落由一系列种群数量与分布范围不一的物种组成,探究群落常见种和稀有种的物种组成差异对生物多样性保护与维持具有重要意义.以南亚热带牛姆林天然林为研究对象,依据模糊聚类算法划分局域群落常见种和稀有种,进而比较常见种和稀有种在科属种构成、群落数量特征和物种组成相似性等方面的差异.结果显示:(1)南亚热带牛姆林群落包含常见种20科29属50种,包括细枝柃(Eurya loquaiana)、罗浮柿(Diospyros morrisiana)和米槠(Castanopsis carlesii)等;稀有种31科46属69种,包括八角枫(Alangium chinense)、沉水樟(Cinnamomum micranthum)和粗叶榕(Ficus hirta)等.(2)稀有种丰富度高于常见种,且存在更多的特有科和特有属,但常见种多度、频度和重要值均高于稀有种.(3)稀有种之间的物种组成相异性最高,而常见种之间物种组成差异性最低.本研究表明常见种决定了局域群落外貌和结构,稀有种是群落生物多样性的有效补充,群落物种组成差异主要来源于稀有种;生物多样性保护应当在区分物种类别后,有针对性地采取保护措施.(图2表4参39) 展开更多
关键词 常见种 稀有种 模糊聚类 物种组成 生物多样性保护
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基于颜色特征量化和改进YOLO v8的番茄成熟度分级检测方法
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作者 张领先 周沁 +4 位作者 姚天雨 裴鑫达 赵立群 满杰 钱井 《农业机械学报》 北大核心 2026年第2期193-202,224,共11页
番茄的成熟度与其品质密切相关,是生产中采摘和分拣等环节的重要依据。针对作物成熟度分级检测系统功能简单,人工升级系统成本较大的问题,本文以番茄为例,采集并构建自然场景下番茄图像数据集,设计以番茄果实成熟度分级算法为基础的番... 番茄的成熟度与其品质密切相关,是生产中采摘和分拣等环节的重要依据。针对作物成熟度分级检测系统功能简单,人工升级系统成本较大的问题,本文以番茄为例,采集并构建自然场景下番茄图像数据集,设计以番茄果实成熟度分级算法为基础的番茄图像半自动标注算法对采集后的数据进行标注,在YOLO v8模型基础上,将FPN结构替换为BiFPN结构实现更高效的多尺度特征融合,利用SE注意力机制对空间和通道进行融合特征提取,引入Focal SIoU损失函数对预测框与真实框之间的角度差异进行度量,构建基于颜色特征量化和改进YOLO v8的番茄成熟度分级检测模型YOLO v8BFS,识别番茄生长过程的5个不同成熟度。试验结果表明,本文模型较好地解决了自然复杂场景下番茄成熟度分级检测的错漏检问题,在模型浮点运算量(FLOPs)、参数量(Params)和内存占用量有少量增加的条件下,本文模型的平均精度均值为94.10%相较原模型YOLO v8提高3.0个百分点。通过与Faster R-CNN-Resnet50、YOLO v5、YOLO v7-tiny、YOLO v8、YOLO v10和YOLO 11目标检测模型对比,本文在检测精度具有显著优势,为番茄成熟度的检测提供了一种可靠的方法。 展开更多
关键词 番茄成熟度 自然场景 颜色特征量化 YOLO v8
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基于改进自编码器和TFT的发动机剩余寿命预测模型 被引量:1
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作者 谭娜 郭嘉玺 +3 位作者 李耀华 石瑞勃 黄金煜昊 雷欣然 《航空动力学报》 北大核心 2026年第2期144-155,共12页
针对航空发动机多源传感器数据在时变工况下退化特征难表征的问题,提出融合改进型卷积自编码器与temporal fusion transformer(TFT)解码器的预测模型,通过多尺度时空特征融合提升了剩余寿命单点预测精度与时变不确定性量化能力。改进的... 针对航空发动机多源传感器数据在时变工况下退化特征难表征的问题,提出融合改进型卷积自编码器与temporal fusion transformer(TFT)解码器的预测模型,通过多尺度时空特征融合提升了剩余寿命单点预测精度与时变不确定性量化能力。改进的卷积自编码器利用其多尺度卷积单元(MSCU)从多维传感器时序数据中提取不同尺度下的特征信息,灵活捕获序列中信息间的局部依赖关系,同时避免了信息丢失问题。TFT解码器通过特征选择模块和多头注意力机制有效捕捉了数据中的全局依赖关系,并通过这些机制揭示了特征的重要性,从而提供了对数据特征影响程度的解释。采用公开数据集进行实验验证,与先进预测模型的比较分析表明,MS1DCAE_TFT模型在FD001与FD003数据集上的方均根误差和分数指标至少提高了0.2%和65.5%,同时分位数回归预测了其寿命区间进行了不确定性量化,可为发动机剩余寿命预测提供可靠的解决方案。 展开更多
关键词 不确定性量化 多尺度卷积单元 temporal fusion transformers解码器 剩余寿命预测 分位数回归
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骨骼肌脂肪浸润的评估方法:定量磁共振成像
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作者 王静 李军飞 赵建 《磁共振成像》 北大核心 2026年第1期201-207,共7页
骨骼肌脂肪浸润(fat infiltration,FI)广泛参与多种疾病的病理发展进程,准确评估肌肉FI的程度对于制定有效的治疗方案及干预疾病进展具有至关重要的意义。放射学参数量化FI,特别是基于定量磁共振成像(quantitative magnetic resonance i... 骨骼肌脂肪浸润(fat infiltration,FI)广泛参与多种疾病的病理发展进程,准确评估肌肉FI的程度对于制定有效的治疗方案及干预疾病进展具有至关重要的意义。放射学参数量化FI,特别是基于定量磁共振成像(quantitative magnetic resonance imaging,qMRI)技术的衍生参数,已经展现出作为疾病诊断要素和代谢风险预测工具的巨大潜力。本文重点介绍了qMRI技术,包括化学位移编码磁共振成像(chemical shift encoding magnetic resonance imaging,CSE-MRI)、磁共振波谱(magnetic resonance spectroscopy,MRS)、T1/T2 mapping及纹理分析等的优势与局限性,及其在肌营养不良症、代谢性疾病及骨关节炎相关退行性病变等疾病诊断与监测中的临床应用。研究显示,qMRI技术能够精确量化肌肉FI,有望成为肌肉病理领域无创诊断的重要工具。 展开更多
关键词 定量磁共振成像 脂肪定量 肌肉脂肪浸润 生物标志物 无创诊断
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环境激励下大跨度斜拉桥模态参数识别的贝叶斯谱分解法研究
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作者 封周权 张吉仁 +4 位作者 温青 石双发 景强 高文博 华旭刚 《振动工程学报》 北大核心 2026年第2期321-329,共9页
近年来,由于贝叶斯模态识别方法优越的不确定性量化能力,其在大跨度桥梁领域的应用日益广泛。为了进一步提升贝叶斯模态参数识别的计算效率,基于频域分解法(FDD)与贝叶斯谱密度法(BSDA)的思想,提出了贝叶斯谱分解法(BSD)。分别对每阶模... 近年来,由于贝叶斯模态识别方法优越的不确定性量化能力,其在大跨度桥梁领域的应用日益广泛。为了进一步提升贝叶斯模态参数识别的计算效率,基于频域分解法(FDD)与贝叶斯谱密度法(BSDA)的思想,提出了贝叶斯谱分解法(BSD)。分别对每阶模态附近的响应谱矩阵进行奇异值分解,得到奇异值(包含频率和阻尼信息)和奇异向量(包含振型信息);利用奇异值和奇异向量的统计特性推导了待识别模态参数的后验概率分布函数,将模态参数识别转化为求最大后验概率点的优化问题;采用高斯分布近似后验概率分布函数以实现识别结果的不确定性量化。通过一个6层框架的数值模型对贝叶斯谱分解法的有效性进行了验证。随后将贝叶斯谱分解法应用于一座大跨度斜拉桥中,利用环境振动数据识别得到了桥梁的模态参数,并与随机子空间法(SSI)识别结果进行了对比分析,识别结果进一步证明了贝叶斯谱分解法的有效性和先进性。 展开更多
关键词 大跨度斜拉桥 模态识别 贝叶斯推理 环境振动 谱分解 不确定性量化
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基于生理-心理感知的昆明市公园园林植物群落秋季色彩量化研究
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作者 周丽 王锦 《中国园林》 北大核心 2026年第1期123-130,共8页
色彩是园林植物群落中最直观鲜明的观赏特征,给人以不同的生理感知和心理联想,进而促进人们的身心健康。以昆明市城市公园园林植物群落为研究对象,采用MATLAB软件量化园林植物群落的色彩特征,结合人体生理心理指标测试法(PPI)量化人们... 色彩是园林植物群落中最直观鲜明的观赏特征,给人以不同的生理感知和心理联想,进而促进人们的身心健康。以昆明市城市公园园林植物群落为研究对象,采用MATLAB软件量化园林植物群落的色彩特征,结合人体生理心理指标测试法(PPI)量化人们对园林植物群落色彩的感知,探讨园林植物群落色彩不同搭配组合与人们生理、心理感知之间的关系。结果表明:1)园林植物群落秋季色彩以绿色系为基调,橙色系色彩占比相对较多,黄色系和红色系色彩占比相近,色彩变化丰富;2)以绿、橙、黄色系占比划分的4类群落,T1类群落的黄色占比最大,T2类群落的绿色占比最大,T3类群落的橙色占比最大;绿色、橙色、黄色等12个特征在4类群落间差异极显著;3)不同色彩特征类型的园林植物群落唤醒了人体生理、心理感知,T4类群落的色彩特征更利于生理放松,T1类群落的色彩特征更利于心理放松;4)利于人体生理和心理放松的园林植物群落,以绿色为基调色彩,主色系4~6种;色彩搭配比例为绿:橙:黄:蓝比值为25:12:9:1、24:5:3:1和15:2:1:1;绿:橙:黄:红:蓝比值为22:28:12:1:2和12:6:2:1:1;绿:橙:黄:红:蓝:紫比值为17:7:2:1:2:1。在昆明市公园的秋季植物景观营造中,可以考虑此园林植物群落色彩的配置比例,营造既有观赏价值又有利于人体身心健康的园林植物景观。 展开更多
关键词 风景园林 园林植物群落 色彩特征 色彩量化 生理-心理感知 昆明市公园
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锆基金属玻璃的电子探针元素定量面分析方法
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作者 李明辉 吴金金 +3 位作者 葛立发 郜鲜辉 宋武林 周芃 《理化检验(物理分册)》 2026年第2期23-26,共4页
采用电子探针方法对锆基金属玻璃进行元素定量面分析,研究不同分析模式和加速电压对面分析结果的影响,并优化了工作曲线。结果表明:选择Peak Search模式,在加速电压为15 kV的条件下,利用两点法定量曲线可以得到准确性较高的面分析结果。
关键词 电子探针 锆基金属玻璃 面分析 定量化 加速电压
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府际关系视角下健康中国政策协同性研究——基于LDA和社会网络的文本量化分析
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作者 王培刚 吴婧 王超 《甘肃行政学院学报》 2026年第1期60-70,共11页
加强府际政策协同是推进健康中国战略向纵深发展的重要保障。文章基于160份健康中国政策文本,从横向与纵向府际维度搭建央地政策“主题-工具-主体”三维协同分析框架,综合运用LDA主题模型与社会网络分析方法,系统探究了央地政策协同特... 加强府际政策协同是推进健康中国战略向纵深发展的重要保障。文章基于160份健康中国政策文本,从横向与纵向府际维度搭建央地政策“主题-工具-主体”三维协同分析框架,综合运用LDA主题模型与社会网络分析方法,系统探究了央地政策协同特征。研究发现:一是央地政策主题整体协同,呈现中央强引领、地方重落实的特征,央地政策主题虽有差异但属于合理的政策协同弹性区间;二是政策工具分布失衡,表现为供给主导的结构性依赖,需求型工具占比显著不足;三是政策主体协作网络“核心-边缘”特征显著,央地横向与纵向联动的立体化协作体系尚未完全形成;四是三维协同相互作用,形成主体为基、主题引领、工具支撑的非对称互动形态。据此,文章认为该战略的实施需构建主题协同动态调适机制,优化政策工具组成结构,健全主体间利益协调和激励机制,强化府际政策协同的制度支撑,从而提升健康中国政策体系整体治理效能。 展开更多
关键词 健康中国 政策协同 府际关系 文本量化
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生物多样性金融的理论研究与实践探索——基于鄱阳湖生物多样性保护贷款案例
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作者 束兰根 《新金融》 北大核心 2026年第2期35-44,共10页
生物多样性保护是可持续发展的重要基础,金融工具创新是破解资金缺口与市场化机制缺失的有效路径。本文以鄱阳湖生物多样性保护指标挂钩银团贷款案例为样本,聚焦生物多样性金融理论研究与实践,解析“保护共识落地—产业转型协同—金融... 生物多样性保护是可持续发展的重要基础,金融工具创新是破解资金缺口与市场化机制缺失的有效路径。本文以鄱阳湖生物多样性保护指标挂钩银团贷款案例为样本,聚焦生物多样性金融理论研究与实践,解析“保护共识落地—产业转型协同—金融工具赋能”的治理协同逻辑,探索生态保护、产业转型与金融创新的多维融合模式。随着生物多样性保护上升至国家战略,针对生物多样性金融起步阶段所存在的问题,本文提出完善政策体系、创新金融产品、强化风险管理、参与全球治理等建议,旨在推动生物多样性金融发展,以市场化金融工具深度赋能生物多样性保护。 展开更多
关键词 生物多样性金融 指标挂钩银团贷款 产业关联 生态价值量化
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