期刊文献+
共找到94,450篇文章
< 1 2 250 >
每页显示 20 50 100
Global Mapping of Three-Dimensional Urban Structures Reveals Escalating Utilization in the Vertical Dimension and Pronounced Building Space Inequality 被引量:1
1
作者 Xiaoping Liu Xinxin Wu +6 位作者 Xuecao Li Xiaocong Xu Weilin Liao Limin Jiao Zhenzhong Zeng Guangzhao Chen Xia Li 《Engineering》 2025年第4期86-99,共14页
Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significan... Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significant gap in detailed and consistent data on 3D building space structures with global coverage due to the challenges inherent in the data collection and model calibration processes.In this study,we constructed a global urban structure(GUS-3D)dataset,including building volume,height,and footprint information,at a 500 m spatial resolution using extensive satellite observation products and numerous reference building samples.Our analysis indicated that the total volume of buildings worldwide in2015 exceeded 1×10^(12)m^(3).Over the 1985 to 2015 period,we observed a slight increase in the magnitude of 3D building volume growth(i.e.,it increased from 166.02 km3 during the 1985–2000 period to 175.08km3 during the 2000–2015 period),while the expansion magnitudes of the two-dimensional(2D)building footprint(22.51×10^(3) vs 13.29×10^(3)km^(2))and urban extent(157×10^(3) vs 133.8×10^(3)km^(2))notably decreased.This trend highlights the significant increase in intensive vertical utilization of urban land.Furthermore,we identified significant heterogeneity in building space provision and inequality across cities worldwide.This inequality is particularly pronounced in many populous Asian cities,which has been overlooked in previous studies on economic inequality.The GUS-3D dataset shows great potential to deepen our understanding of the urban environment and creates new horizons for numerous 3D urban studies. 展开更多
关键词 three-dimensionAL Global mapping Building volume Building height Building space inequality
在线阅读 下载PDF
Native T1 mapping值显著延长心脏纤维瘤一例
2
作者 文涛 张辉 +3 位作者 甘铁军 胡万均 李世兰 张静 《磁共振成像》 北大核心 2026年第1期120-122,共3页
本研究为回顾性研究,遵守《赫尔辛基宣言》,并经兰州大学第二医院伦理委员会审核批准,免除受试者知情同意,批准文号:2025A-547。患儿,女,2月8天,因“发现心脏肿瘤2月”于2024年11月就诊于我院,患儿于2个月前出生后外院检查提示左心室肿... 本研究为回顾性研究,遵守《赫尔辛基宣言》,并经兰州大学第二医院伦理委员会审核批准,免除受试者知情同意,批准文号:2025A-547。患儿,女,2月8天,因“发现心脏肿瘤2月”于2024年11月就诊于我院,患儿于2个月前出生后外院检查提示左心室肿瘤,未予特殊诊治,现为进一步明确诊治收住我院心脏外科。患儿足月(38+6周)、顺产、无心脏肿瘤家族史。查体:心前区无隆起,心界不大,心音有力、律齐,胸骨左缘第2~3肋间可闻及3/6及吹风样杂音,静息血氧饱和度100%。 展开更多
关键词 心脏肿瘤 心脏纤维瘤 多模态磁共振成像 心脏磁共振 Native T1 mapping
暂未订购
T2 Mapping联合DWI序列评估直肠癌脉管侵犯价值研究
3
作者 李茜玮 陈安良 +2 位作者 王楠 林良杰 刘爱连 《中国CT和MRI杂志》 2026年第1期149-152,共4页
目的探讨T2 mapping与DWI序列预测直肠癌脉管侵犯的价值。方法回顾性分析经本院行3.0T MRI扫描且经术后病理证实的直肠癌脉管侵犯13例,脉管非侵犯20例,2名观察者分别于瘤体显示最大层面参考增强动脉期图像及DWI图像于T2 mapping及ADC图... 目的探讨T2 mapping与DWI序列预测直肠癌脉管侵犯的价值。方法回顾性分析经本院行3.0T MRI扫描且经术后病理证实的直肠癌脉管侵犯13例,脉管非侵犯20例,2名观察者分别于瘤体显示最大层面参考增强动脉期图像及DWI图像于T2 mapping及ADC图像上测量病灶T2值及ADC值。采用组内相关系数(intraclass correlation cofficient,ICC)评估两名观察者测量参数值的一致性。采用独立样本t检验或Mann-Whitney U检验分析两组病例各参数的差异。采用Logistic回归计算有统计学差异的参数联合评估直肠癌LVI的预测值。采用ROC曲线评估有差异参数单独或联合的诊断效能,并利用De-Long检验比较各ROC曲线间的差异。采用Pearson相关性检验分析两参数值的相关性。结果2名观察者测量T2值及ADC值一致性好(ICC>0.75)。脉管侵犯组的T2值及ADC值低于非脉管侵犯组(77.15±6.95ms、0.69±0.15mm^(2)/s vs 87.04±7.75ms、0.90±0.21 mm^(2)/s,P<0.05)。ADC值与ADC-T2联合鉴别两组疾病的AUC值比较差异具有统计学意义(P=0.036)。结论T2 mapping和DWI序列可预测直肠癌脉管侵犯,两序列联合效能提升,因此T2值与ADC值联合可为临床诊疗直肠癌脉管侵犯提供参考信息。 展开更多
关键词 直肠癌 脉管侵犯 磁共振成像 T2 mapping成像 弥散加权成像
暂未订购
A Comprehensive Literature Review of AI-Driven Application Mapping and Scheduling Techniques for Network-on-Chip Systems
4
作者 Naveed Ahmad Muhammad Kaleem +5 位作者 Mourad Elloumi Muhammad Azhar Mushtaq Ahlem Fatnassi Mohd Fazil Anas Bilal Abdulbasit A.Darem 《Computer Modeling in Engineering & Sciences》 2026年第1期118-155,共38页
Network-on-Chip(NoC)systems are progressively deployed in connecting massively parallel megacore systems in the new computing architecture.As a result,application mapping has become an important aspect of performance ... Network-on-Chip(NoC)systems are progressively deployed in connecting massively parallel megacore systems in the new computing architecture.As a result,application mapping has become an important aspect of performance and scalability,as current trends require the distribution of computation across network nodes/points.In this paper,we survey a large number of mapping and scheduling techniques designed for NoC architectures.This time,we concentrated on 3D systems.We take a systematic literature review approach to analyze existing methods across static,dynamic,hybrid,and machine-learning-based approaches,alongside preliminary AI-based dynamic models in recent works.We classify them into several main aspects covering power-aware mapping,fault tolerance,load-balancing,and adaptive for dynamic workloads.Also,we assess the efficacy of each method against performance parameters,such as latency,throughput,response time,and error rate.Key challenges,including energy efficiency,real-time adaptability,and reinforcement learning integration,are highlighted as well.To the best of our knowledge,this is one of the recent reviews that identifies both traditional and AI-based algorithms for mapping over a modern NoC,and opens research challenges.Finally,we provide directions for future work toward improved adaptability and scalability via lightweight learned models and hierarchical mapping frameworks. 展开更多
关键词 Application mapping mapping techniques NETWORK-ON-CHIP system on chip optimisation
在线阅读 下载PDF
Design of a Patrol and Security Robot with Semantic Mapping and Obstacle Avoidance System Using RGB-D Camera and LiDAR
5
作者 Shu-Yin Chiang Shin-En Huang 《Computers, Materials & Continua》 2026年第4期1735-1753,共19页
This paper presents an intelligent patrol and security robot integrating 2D LiDAR and RGB-D vision sensors to achieve semantic simultaneous localization and mapping(SLAM),real-time object recognition,and dynamic obsta... This paper presents an intelligent patrol and security robot integrating 2D LiDAR and RGB-D vision sensors to achieve semantic simultaneous localization and mapping(SLAM),real-time object recognition,and dynamic obstacle avoidance.The system employs the YOLOv7 deep-learning framework for semantic detection and SLAM for localization and mapping,fusing geometric and visual data to build a high-fidelity 2D semantic map.This map enables the robot to identify and project object information for improved situational awareness.Experimental results show that object recognition reached 95.4%mAP@0.5.Semantic completeness increased from 68.7%(single view)to 94.1%(multi-view)with an average position error of 3.1 cm.During navigation,the robot achieved 98.0%reliability,avoided moving obstacles in 90.0%of encounters,and replanned paths in 0.42 s on average.The integration of LiDAR-based SLAMwith deep-learning–driven semantic perception establishes a robust foundation for intelligent,adaptive,and safe robotic navigation in dynamic environments. 展开更多
关键词 RGB-D semantic mapping object recognition obstacle avoidance security robot
在线阅读 下载PDF
High‑density genetic mapping enhances genomic selection accuracy for complex traits in Populus
6
作者 Chenchen Guo Tongming Yin Suyun Wei 《Journal of Forestry Research》 2026年第2期290-304,共15页
Populus species,important economic species combining rapid growth with broad ecological adaptability,play a critical role in sustainable forestry and bioenergy production.In this study,we performed whole-genome resequ... Populus species,important economic species combining rapid growth with broad ecological adaptability,play a critical role in sustainable forestry and bioenergy production.In this study,we performed whole-genome resequencing of 707 individuals from a full-sib family to develop comprehensive single nucleotide polymorphism(SNP)markers and constructed a high-density genetic linkage map of 19 linkage groups.The total genetic length of the map reached 3623.65 cM with an average marker interval of 0.34 cM.By integrating multidimensional phenotypic data,89 quantitative trait loci(QTL)associated with growth,wood physical and chemical properties,disease resistance,and leaf morphology traits were identified,with logarithm of odds(LOD)scores ranging from 3.13 to 21.72 Notably,pleiotropic analysis revealed significant colocaliza and phenotypic variance explained between 1.7% and 11.6%.-tion hotspots on chromosomes LG1,LG5,LG6,LG8,and LG14,with epistatic interaction network analysis confirming genetic basis of coordinated regulation across multiple traits.Functional annotation of 207 candidate genes showed that R2R3-MYB and bHLH transcription factors and pyruvate kinase-encoding genes were significantly enriched,suggesting crucial roles in lignin biosynthesis and carbon metabolic pathways.Allelic effect analysis indicated that the frequency of favorable alleles associated with target traits ranged from 0.20 to 0.55.Incorporation of QTL-derived favorable alleles as random effects into Bayesian-based genomic selection models led to an increase in prediction accuracy ranging from 1% to 21%,with Bayesian ridge regression as the best predictive model.This study provides valuable genomic resources and genetic insights for deciphering complex trait architecture and advancing molecular breeding in poplar. 展开更多
关键词 Genomic selection Genetic map Quantitative trait loci GROWTH Disease resistance
在线阅读 下载PDF
Cascading Class Activation Mapping:A Counterfactual Reasoning-Based Explainable Method for Comprehensive Feature Discovery
7
作者 Seoyeon Choi Hayoung Kim Guebin Choi 《Computer Modeling in Engineering & Sciences》 2026年第2期1043-1069,共27页
Most Convolutional Neural Network(CNN)interpretation techniques visualize only the dominant cues that the model relies on,but there is no guarantee that these represent all the evidence the model uses for classificati... Most Convolutional Neural Network(CNN)interpretation techniques visualize only the dominant cues that the model relies on,but there is no guarantee that these represent all the evidence the model uses for classification.This limitation becomes critical when hidden secondary cues—potentially more meaningful than the visualized ones—remain undiscovered.This study introduces CasCAM(Cascaded Class Activation Mapping)to address this fundamental limitation through counterfactual reasoning.By asking“if this dominant cue were absent,what other evidence would the model use?”,CasCAM progressively masks the most salient features and systematically uncovers the hierarchy of classification evidence hidden beneath them.Experimental results demonstrate that CasCAM effectively discovers the full spectrum of reasoning evidence and can be universally applied with nine existing interpretation methods. 展开更多
关键词 Explainable AI class activation mapping counterfactual reasoning shortcut learning feature discovery
在线阅读 下载PDF
Comparative Study on the Diagnostic Efficacy of Conventional MRI Sequences and T2 Mapping Sequences in Cartilage Injury
8
作者 Wang Peng Zhi Liu +1 位作者 Juan Long Chanying Wang 《Journal of Clinical and Nursing Research》 2026年第1期284-291,共8页
Objective:To retrospectively evaluate the diagnostic efficacy of traditional MRI and T2 Mapping quantitative imaging technology for knee joint cartilage injury,clarify the differences in diagnostic value of the two im... Objective:To retrospectively evaluate the diagnostic efficacy of traditional MRI and T2 Mapping quantitative imaging technology for knee joint cartilage injury,clarify the differences in diagnostic value of the two imaging methods in different injury grades and different cartilage subregions,and provide evidence-based basis for the accurate diagnosis of clinical cartilage injury.Methods:Clinical and imaging data of 286 patients with knee joint lesions admitted to the Affiliated Hospital of Xiangtan Medicine and Health Vocational College from January 2020 to June 2023 were collected retrospectively.All patients underwent both traditional MRI sequences and T2 Mapping sequences.The knee joint cartilage was divided into 14 subregions.Two senior radiologists independently diagnosed the images of the two imaging technologies using a blind method and recorded the cartilage injury grades.The sensitivity,specificity,accuracy,positive predictive value,negative predictive value,and area under the receiver operating characteristic curve(AUC)of the two technologies for diagnosing cartilage injury were calculated and compared,and the differences in their diagnostic efficacy in different injury grades and different subregions were analyzed.Results:A total of 4004 cartilage subregions from 286 patients were included in the analysis,including 1836 injured subregions and 2168 normal subregions.The overall sensitivity(89.7%),accuracy(91.2%),and AUC(0.946)of T2 Mapping quantitative imaging for diagnosing cartilage injury were significantly higher than those of traditional MRI(76.3%,82.5%,and 0.852 respectively),with statistically significant differences(p<0.001);there was no significant difference in specificity between the two(93.5%vs 90.8%,p=0.062).Subgroup analysis showed that T2 Mapping had the most significant diagnostic advantage in early cartilage injury(Grade 1),with sensitivity(78.5%)33.2%higher than that of traditional MRI(45.3%)(p<0.001).Conclusion:The diagnostic efficacy of T2 Mapping quantitative imaging for knee joint cartilage injury is significantly superior to that of traditional MRI,especially in the detection of early cartilage injury and accurate evaluation of weight-bearing area injury.Data verify its clinical applicability and reliability.It can be used as an important supplementary method to traditional MRI,and is recommended for the early diagnosis,grading evaluation,and clinical follow-up of cartilage injury. 展开更多
关键词 Traditional MRI T2 mapping Cartilage injury Diagnostic efficacy Retrospective analysis
暂未订购
RNPC-net:Automatic recognition and mapping of weathering degree and groundwater condition of tunnel faces
9
作者 Xiang Wu Fengyan Wang +4 位作者 Jianping Chen Mingchang Wang Lina Cheng Chengyao Zhang Junke Xu 《Journal of Rock Mechanics and Geotechnical Engineering》 2026年第2期1138-1159,共22页
Accurate and rapid recognition of weathering degree(WD)and groundwater condition(GC)is essential for evaluating rock mass quality and conducting stability analyses in underground engineering.Conventional WD and GC rec... Accurate and rapid recognition of weathering degree(WD)and groundwater condition(GC)is essential for evaluating rock mass quality and conducting stability analyses in underground engineering.Conventional WD and GC recognition methods often rely on subjective evaluation by field experts,supplemented by field sampling and laboratory testing.These methods are frequently complex and timeconsuming,making it challenging to meet the rapidly evolving demands of underground engineering.Therefore,this study proposes a rock non-geometric parameter classification network(RNPC-net)to rapidly achieve the recognition and mapping ofWD and GC of tunnel faces.The hybrid feature extraction module(HFEM)in RNPC-net can fully extract,fuse,and utilize multi-scale features of images,enhancing the network's classification performance.Moreover,the designed adaptive weighting auxiliary classifier(AC)helps the network learn features more efficiently.Experimental results show that RNPC-net achieved classification accuracies of 0.8756 and 0.8710 for WD and GC,respectively,representing an improvement of approximately 2%e10%compared to other methods.Both quantitative and qualitative experiments confirm the effectiveness and superiority of RNPC-net.Furthermore,for WD and GC mapping,RNPC-net outperformed other methods by achieving the highest mean intersection over union(mIOU)across most tunnel faces.The mapping results closely align with measurements provided by field experts.The application of WD and GC mapping results to the rock mass rating(RMR)system achieved a transition from conventional qualitative to quantitative evaluation.This advancement enables more accurate and reliable rock mass quality evaluations,particularly under critical conditions of RMR. 展开更多
关键词 Tunnel face Weathering degree Groundwater condition RNPC-net Hybrid feature extraction module Recognition and mapping
在线阅读 下载PDF
Integration of Landsat and MODIS Imagery for Mapping 30-m Cotton Cultivation Areas in Xinjiang,China from 2000 to 2020
10
作者 TAN Zhuting TAN Zhenyu +1 位作者 DUAN Hongtao ZHANG Kaili 《Chinese Geographical Science》 2026年第1期97-108,I0001,共13页
Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultiv... Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultivation management and promoting the sustainable development of the cotton industry.Xinjiang is the primary cotton-producing region in China.However,long-term data of cotton cultiv-ation areas with high spatial resolution are unavailable for Xinjiang,China.Therefore,this study aimed to identify and map an accurate 30-m cotton cultivation area dataset in Xinjiang from 2000 to 2020 by applying a Random Forest(RF)-based method that integrates Landsat and Moderate Resolution Imaging Spectroradiometer(MODIS)images,and validated the applicability and accuracy of dataset at a large spatial scale.Then,this study analyzed the spatiotemporal variations and influencing factors of cotton cultivation in the study period.The results showed that a high classification accuracy was achieved(overall accuracy>85%,F1>0.80),strongly agreeing with county-level agricultural statistical yearbook data(R2>0.72).Significant spatiotemporal variation in the cotton cultivation areas was found in Xinjiang,with a total increase of 1131.26 kha from 2000 to 2020.Notably,cotton cultivation area in southern Xinjiang expan-ded substantially,with that in Aksu increasing from 20.10%in 2000 to 28.17%in 2020,representing an expansion of 374.29 kha.In northern Xinjiang,the cotton areas in the Tacheng region also exhibited significant increased by almost ten percentage points in the same period.In contrast,cotton cultivation in eastern Xinjiang declined,decreasing from 2.22%in 2000 to merely 0.24%in 2020.Standard deviation ellipse analysis revealed a‘northeast-southwest’spatial distribution,with the centroid consistently located in Aksu and shifting 102.96 km over the 20-yr period.Pearson correlation analysis indicated that socioeconomic factors had a stronger influence on cotton cultivation than climatic factors,with effective irrigation area(r=0.963,P<0.05)and total agricultural machinery power(r=0.823)showing significant positive correlations,whereas climatic variables exhibiting weak associations(r<0.200).These results provide valuable scientific data for informed agricultural management,sustainable development,and policymaking. 展开更多
关键词 cotton cultivation mapping long-term series LANDSAT Moderate Resolution Imaging Spectroradiometer(MODIS) remote sensing Xinjiang China
在线阅读 下载PDF
Mapping editorial identity and thematic evolution in the Journal of Psychology in Africa(2008-2024):A meta-editorial framework analysis
11
作者 Joon-ho Kim 《Journal of Psychology in Africa》 2026年第1期117-130,共14页
This study presents a reflective bibliometric review of 1457 peer-reviewed articles published in the Journal of Psychology in Africa(2008-2024,17 years),using a Meta-Editorial Mapping Framework(MEMF)analysis.The MEMF ... This study presents a reflective bibliometric review of 1457 peer-reviewed articles published in the Journal of Psychology in Africa(2008-2024,17 years),using a Meta-Editorial Mapping Framework(MEMF)analysis.The MEMF integrates citation metrics,keyword novelty ratios,TF-IDF weighting,and cluster-based topic modeling to trace long-term thematic trends and editorial evolution.Findings reveal sustained attention to foundational domains such as mental health,education,and identity,alongside a gradual integration of emergent themes including digital well-being,organizational behavior,and post-pandemic adaptation.Articles with moderate topical novelty(40%-60% new keywords)achieved the highest citation and usage metrics,suggesting that integrative innovation enhances scholarly impact.Clustering analyses indicate that the journal’s content forms overlapping conceptual domains rather than isolated silos.These insights contribute to editorial strategy,authorial positioning,and the future design of regional academic platforms.Moreover,the findings provide evidence supporting the use of the MEMF as a replicable tool for meta-editorial analysis across disciplinary and geographic boundaries. 展开更多
关键词 meta-editorial mapping framework(MEMF) topic evolution keyword novelty bibliometric analysis editorial strategy scholarly engagement Journal of Psychology in Africa
在线阅读 下载PDF
Three-dimensional computed tomography mapping of posterior malleolar fractures 被引量:3
12
作者 Qi-Hang Su Juan Liu +5 位作者 Yan Zhang Jun Tan Mei-Jun Yan Kai Zhu Jin Zhang Cong Li 《World Journal of Clinical Cases》 SCIE 2020年第1期29-37,共9页
BACKGROUND Posterior malleolar fractures have been reported to occur in<40%of ankle fractures.AIM To reveal the recurrent patterns and characteristics of posterior malleolar fractures by creating fracture maps of t... BACKGROUND Posterior malleolar fractures have been reported to occur in<40%of ankle fractures.AIM To reveal the recurrent patterns and characteristics of posterior malleolar fractures by creating fracture maps of the posterior malleolar fractures through the use of computed tomography mapping.METHODS A consecutive series of posterior malleolar fractures was used to create threedimensional reconstruction images,which were oriented and superimposed to fit an ankle model template by both aligning specific biolandmarks and reducing reconstructed fracture fragments.Fracture lines were found and traced in order to generate an ankle fracture map.RESULTS This study involved 112 patients with a mean age of 49,comprising 32 pronationexternal rotation grade IV fractures and 80 supination-external rotation grade IV fractures according to the Lauge-Hansen classification system.Three-dimensional maps showed that the posterior ankle fracture fragments in the supinationexternal rotation grade IV group were relatively smaller than those in the pronation-external rotation grade IV group after posterior malleolus fracture.In addition,the distribution analyses on posterior malleolus fracture lines indicated that the supination-external rotation grade IV group tended to have higher linear density but more concentrated and orderly distribution fractures compared to the pronation-external rotation grade IV group.CONCLUSION Fracture maps revealed the fracture characteristics and recurrent patterns of posterior malleolar fractures,which might help to improve the understanding of ankle fracture as well as increase opportunities for follow-up research and aid clinical decision-making. 展开更多
关键词 three-dimensional imaging mapS Ankle fractures Computed tomography
暂未订购
A modified method of discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces 被引量:14
13
作者 Keshen Zhang Wei Wu +3 位作者 Hehua Zhu Lianyang Zhang Xiaojun Li Hong Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第3期571-586,共16页
This paper presents an automated method for discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces.Specifically,the method consists of five steps:(1)detection of trace feature points by... This paper presents an automated method for discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces.Specifically,the method consists of five steps:(1)detection of trace feature points by normal tensor voting theory,(2)co ntraction of trace feature points,(3)connection of trace feature points,(4)linearization of trace segments,and(5)connection of trace segments.A sensitivity analysis was then conducted to identify the optimal parameters of the proposed method.Three field cases,a natural rock mass outcrop and two excavated rock tunnel surfaces,were analyzed using the proposed method to evaluate its validity and efficiency.The results show that the proposed method is more efficient and accurate than the traditional trace mapping method,and the efficiency enhancement is more robust as the number of feature points increases. 展开更多
关键词 Rock mass DISCONTINUITY three-dimensional point clouds Trace mapping
在线阅读 下载PDF
Left Bundle Branch Ablation Guided by a Three-Dimensional Mapping System: A Novel Method for Establishing a Heart Failure Animal Model
14
作者 Pengkang He Han Jin +3 位作者 Yiran Hu Sixian Weng Sijing Cheng Hao Huang 《Cardiovascular Innovations and Applications》 2023年第1期574-580,共7页
Objective:Few studies have been conducted to establish animal models of left bundle branch block by using three-dimensional mapping systems.This research was aimed at creating a canine left bundle branch block model b... Objective:Few studies have been conducted to establish animal models of left bundle branch block by using three-dimensional mapping systems.This research was aimed at creating a canine left bundle branch block model by using a three-dimensional mapping system.Materials and Methods:We used a three-dimensional mapping system to map and ablate the left bundle branch in beagles.Results:Ten canines underwent radiofrequency ablation,among which left bundle branch block was successfully es-tablished in eight,one experienced ventricular fibrillation,and one developed third-degree atrioventricular block.The maximum HV interval measured within the left ventricle was 29.00±2.93 ms,and the LBP-V interval at the ablation site was 20.63±2.77 ms.The LBP-V interval at the ablation target was 71.08%of the maximum HV interval.Conclusion:This three-dimensional mapping system is a reliable and effective guide for ablation of the left bundle branch in dogs. 展开更多
关键词 left bundle branch block heart failure animal model CANINE three-dimensional mapping ablation
暂未订购
Application of Three-dimensional Laser Scanning Technology in the Teaching Practice of Surveying and Mapping of Ancient Buildings
15
作者 Yapeng DUAN Junli LIU +2 位作者 Zhendong LIU Dingtao CAI Shaomin NI 《Asian Agricultural Research》 2019年第11期77-80,共4页
Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser sca... Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser scanning technology.Based on the practical application,this paper puts forward the discussion of related problems and matters needing attention.This has a certain reference significance for the study of new technology in surveying and mapping of ancient buildings. 展开更多
关键词 three-dimensionAL laser SCANNING technology SURVEYING and mapping of ANCIENT BUILDINGS
在线阅读 下载PDF
A physics-informed machine learning solution for landslide susceptibility mapping based on three-dimensional slope stability evaluation
16
作者 WANG Yun-hao WANG Lu-qi +4 位作者 ZHANG Wen-gang LIU Song-lin SUN Wei-xin HONG Li ZHU Zheng-wei 《Journal of Central South University》 CSCD 2024年第11期3838-3853,共16页
Landslide susceptibility mapping is a crucial tool for disaster prevention and management.The performance of conventional data-driven model is greatly influenced by the quality of the samples data.The random selection... Landslide susceptibility mapping is a crucial tool for disaster prevention and management.The performance of conventional data-driven model is greatly influenced by the quality of the samples data.The random selection of negative samples results in the lack of interpretability throughout the assessment process.To address this limitation and construct a high-quality negative samples database,this study introduces a physics-informed machine learning approach,combining the random forest model with Scoops 3D,to optimize the negative samples selection strategy and assess the landslide susceptibility of the study area.The Scoops 3D is employed to determine the factor of safety value leveraging Bishop’s simplified method.Instead of conventional random selection,negative samples are extracted from the areas with a high factor of safety value.Subsequently,the results of conventional random forest model and physics-informed data-driven model are analyzed and discussed,focusing on model performance and prediction uncertainty.In comparison to conventional methods,the physics-informed model,set with a safety area threshold of 3,demonstrates a noteworthy improvement in the mean AUC value by 36.7%,coupled with a reduced prediction uncertainty.It is evident that the determination of the safety area threshold exerts an impact on both prediction uncertainty and model performance. 展开更多
关键词 machine learning physics-informed model negative samples selection INTERPRETABILITY landslide susceptibility mapping
在线阅读 下载PDF
Real-time volume rendering for three-dimensional fetal ultrasound using volumetric photon mapping
17
作者 Jing Zou Jing Qin 《Visual Computing for Industry,Biomedicine,and Art》 2024年第1期83-97,共15页
Three-dimensional(3D)fetal ultrasound has been widely used in prenatal examinations.Realistic and real-time volumetric ultrasound volume rendering can enhance the effectiveness of diagnoses and assist obstetricians an... Three-dimensional(3D)fetal ultrasound has been widely used in prenatal examinations.Realistic and real-time volumetric ultrasound volume rendering can enhance the effectiveness of diagnoses and assist obstetricians and pregnant mothers in communicating.However,this remains a challenging task because(1)there is a large amount of speckle noise in ultrasound images and(2)ultrasound images usually have low contrasts,making it difficult to distinguish different tissues and organs.However,traditional local-illumination-based methods do not achieve satisfactory results.This real-time requirement makes the task increasingly challenging.This study presents a novel real-time volume-rendering method equipped with a global illumination model for 3D fetal ultrasound visualization.This method can render direct illumination and indirect illumination separately by calculating single scattering and multiple scattering radiances,respectively.The indirect illumination effect was simulated using volumetric photon mapping.Calculating each photon’s brightness is proposed using a novel screen-space destiny estimation to avoid complicated storage structures and accelerate computation.This study proposes a high dynamic range approach to address the issue of fetal skin with a dynamic range exceeding that of the display device.Experiments show that our technology,compared to conventional methodologies,can generate realistic rendering results with far more depth information. 展开更多
关键词 three-dimensional fetal ultrasound Volume rendering Photon mapping Global illumination
在线阅读 下载PDF
3.0T磁共振T2 mapping序列联合血清新饱食分子蛋白1水平检测在老年膝关节早期骨关节炎诊断中的应用价值
18
作者 唐利 巩玉荣 +2 位作者 曾立叶 高艳芳 邓成哲 《实用医学杂志》 北大核心 2025年第8期1238-1242,共5页
目的探讨3.0 T磁共振(MRI)T2 mapping序列联合血清新饱食分子蛋白1(nesfatin-1)水平对老年膝关节早期骨关节炎(OA)的诊断价值。方法选取2023年5月至2024年5月医院收治的膝关节OA的97例老年患者(OA组)和52例同期老年体检者(对照组),根据... 目的探讨3.0 T磁共振(MRI)T2 mapping序列联合血清新饱食分子蛋白1(nesfatin-1)水平对老年膝关节早期骨关节炎(OA)的诊断价值。方法选取2023年5月至2024年5月医院收治的膝关节OA的97例老年患者(OA组)和52例同期老年体检者(对照组),根据X线结果将膝关节OA组分为早期组和非早期组,均接受3.0T MRI T2 mapping序列扫描检测膝关节软骨区域T2值,检测血清nesfatin-1水平,比较上述指标差异并采用ROC曲线分析其对老年膝关节早期OA的诊断价值。结果97例老年膝关节OA患者中,早期组35例,非早期组62例,OA组患者膝关节5个软骨区域的T2值及nesfatin-1血清均高于对照组(P<0.05),早期组均低于非早期组(P<0.05);膝关节软骨区域T2值和血清nesfatin-1水平单独诊断早期OA的AUC在0.774~0.871范围,联合诊断的AUC为0.939。结论3.0 T磁共振T2 mapping序列联合血清nesfatin-1水平检测对老年膝关节早期OA具有较高的诊断价值。 展开更多
关键词 膝关节早期骨关节炎 老年 磁共振 T2 mapping序列 新饱食分子蛋白1
暂未订购
基于Maps统计分析的冶金尘泥还原焙烧机理
19
作者 李强 陈铁军 +3 位作者 陈佳乐 黄宇平 李圣辉 李奇勇 《钢铁》 北大核心 2026年第1期188-200,共13页
冶金尘泥的转底炉处理工艺是目前钢铁行业采用的主要处置工艺,但在实际生产过程中经常出现还原焙烧不均匀的问题。利用微观扫描电子显微镜(scanning electron microscopy,SEM)分析结合宏观Maps统计分析,对冶金尘泥还原焙烧的不均匀性进... 冶金尘泥的转底炉处理工艺是目前钢铁行业采用的主要处置工艺,但在实际生产过程中经常出现还原焙烧不均匀的问题。利用微观扫描电子显微镜(scanning electron microscopy,SEM)分析结合宏观Maps统计分析,对冶金尘泥还原焙烧的不均匀性进行详细的可视化、数据化分析。研究结果表明,冶金尘泥在焙烧温度为1250℃、焙烧时间为15 min的条件下,熟球金属化率达到89.04%、脱锌率达到81.66%、抗压强度达到3.03 kN,熟球金属化率和脱锌率会随着焙烧温度提高和焙烧时间延长而进一步提高,但熟球抗压强度在焙烧时间过长时反而逐渐降低;熟球Maps统计分析表明,提高焙烧温度更有利于提高熟球外圈和下部的还原程度,而延长焙烧时间也更有利于提高熟球下部还原程度,但对熟球内部和外圈还原程度的提升作用比较相似;同时,提高焙烧温度也更有利于提升熟球下部的致密化程度,降低熟球上、下孔隙结构的不均匀性,进而显著提高熟球整体抗压强度;但焙烧时间过长会导致熟球中小孔隙融合为大孔隙,反而降低熟球抗压强度。此外,熟球中硅酸盐(渣相)和浮氏体(FexO)更容易破裂,而金属铁(Fe)可延缓裂纹蔓延,因而,适当提高熟球金属化率、降低硅酸盐(渣相)含量也有利于提高其抗压强度。基于Maps统计分析探究了冶金尘泥还原焙烧过程中物相及孔隙的变化规律,分析结果可以为转底炉工艺处理冶金尘泥的生产实践提供指导和建议。 展开更多
关键词 冶金尘泥 焙烧温度 焙烧时间 maps统计分析 金属化率 抗压强度 转底炉 熟球
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部