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基于非负约束的重力向下延拓BTTB-MRNSD方法

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测绘学报 2024年第8期53卷 1552-1563页

作者：刘天佑曾小牛李夕海火箭军工程大学核工程学院陕西西安710025 海洋油气勘探国家工程研究中心北京100028

向下延拓作为处理与解释重力数据的一项重要技术,因其计算的不适定性而备受研究人员的关注。空间域延拓方法一般延拓精度较高,但通常计算复杂度较大。本文首先根据重力异常数据的特点,借鉴图像复原问题的处理思路,提出了一种重力向下延... 详细信息

向下延拓作为处理与解释重力数据的一项重要技术,因其计算的不适定性而备受研究人员的关注。空间域延拓方法一般延拓精度较高,但通常计算复杂度较大。本文首先根据重力异常数据的特点,借鉴图像复原问题的处理思路,提出了一种重力向下延拓等效数学模型。然后,基于系数矩阵的块-托普利茨-托普利茨-块(BTTB)结构特点,本文提出了一种具有非负约束的空间-波数混合域下延迭代方法。该方法克服了空间域延拓计算复杂度大的问题,计算效率较高。基于理论重力模型和实测异常数据的对比试验表明,本文提出的重力下延方法具有相对较高的下延精度和稳定性,且收敛性较好。

关键词：重力非负约束向下延拓最速下降法 BTTB矩阵

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基于MSSA-XGBoost小样本核爆地震事件分类

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Applied Geophysics 2024年第1期21卷 108-118,205页

作者：李鸿儒李夕海谭笑枫张云刘天佑刘继昊牛超火箭军工程大学核工程学院陕西西安710025

核爆地震与天然地震事件的分类鉴别是全面禁止核试验条约中的一项重要任务。受限于核爆数据数量缺乏,论文研究了XGBoost模型在小样本场景下两类事件的分类问题,并利用SSA算法对模型关键超参数进行自主寻优。同时针对SSA算法的不足,采用... 详细信息

核爆地震与天然地震事件的分类鉴别是全面禁止核试验条约中的一项重要任务。受限于核爆数据数量缺乏,论文研究了XGBoost模型在小样本场景下两类事件的分类问题,并利用SSA算法对模型关键超参数进行自主寻优。同时针对SSA算法的不足,采用高斯混沌映射方法、提出种群比例动态调整策略和引入步长调整因子进行改进,构建了MSSA-XGBoost分类模型。模型解决了初始种群分布不均匀,导致种群多样性减少,影响算法收敛速度的问题;解决了麻雀种群比例固定,容易陷入局部最优解的问题;以及解决了发现者位置更新步长固定,从而限制算法全局搜索能力与寻优效率的问题,实现了避免人工特征提取和XGBoost迭代次数、最大树深以及学习率三个重要超参数的自主寻优,在小样本地震事件分类中取得了优异的效果。实验结果表明,MSSA-XGBoost模型分类准确率达到了96.37%,优于原模型93.47%,也优于支持向量机与卷积神经网络,同时较原始模型计算效率提升了近30%。

关键词：核爆地震分类 XGBoost 麻雀算法小样本特征提取

基于分形径向谱的位场向下延拓截止波数自动确定方法

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地球物理学进展 2024年第1期39卷 403-411页

作者：曾小牛刘天佑谭笑枫张云李夕海火箭军工程大学核工程学院西安710025 海洋油气勘探国家工程研究中心北京100028

向下延拓是重磁位场数据处理与解释的一项重要技术,并因其固有的不稳定性而成为研究的热点.为获得稳定向下延拓结果,波数域向下延拓一般通过附加低通滤波器或改造向下延拓因子来完成.由此,滤波器或改造因子的截止波数则是精确向下延拓... 详细信息

向下延拓是重磁位场数据处理与解释的一项重要技术,并因其固有的不稳定性而成为研究的热点.为获得稳定向下延拓结果,波数域向下延拓一般通过附加低通滤波器或改造向下延拓因子来完成.由此,滤波器或改造因子的截止波数则是精确向下延拓的关键.本文基于分形修正径向平均功率谱的物理特性,提出一种位场向下延拓截止波数的自动确定方法.基于理论重力模型和航磁实测数据的向下延拓对比实验结果表明:(1)本文所提出的自动确定方法物理意义明确,能快速有效地确定截止波数并进而获得向下延拓正则参数;(2)基于本文方法的正则化向下延拓结果优于改进导数迭代法的向下延拓结果.

关键词：位场向下延拓径向平均功率谱截止波数分形

Contribution to the Investigation of Structure and Origin of the East African Graben by Gravi metry

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Geo-Spatial Information Science 2005年第4期8卷 291-296页

作者： Tondozi Keto liu tianyou Faculty of Geophysics China University of Geosciences 1 Lumo Road Wuhan 430074 China 不详

For our investigation we have 235 measurements done in the east part of Democratic Republic of Congo by *** during a magnetic survey including the graben region from the parallel joining Goma city and Mahagi city, the region between Albert and Aka lakes, and the route from Aba to Kinsagani. During the surveys the density of recording points has been selected according to the importance of anomalies. In this way, the offset was 1 km where the disturbance was high in Goma city and 20 km have been sufficient along the route from Aba to Kinsagani. For the topographic and isostatic reductions only one cartographic document has been chosen that was the international map of the scale 1/1 000 000 which presents a certain characteristic of homogeneity.

关键词： gravity anomaly data reductions compensation offset isostasy

超声引导下置管引流联合腹腔镜阑尾切除术在化脓性阑尾炎中的应用效果

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临床医学研究与实践 2024年第18期9卷 45-48页

作者：刘天友贺克平杨林淮安市第二人民医院/徐州医科大学附属淮安医院超声医学科江苏淮安223002 淮安市第五人民医院超声科江苏淮安223300 淮安市第二人民医院/徐州医科大学附属淮安医院胃肠外科江苏淮安223002

目的探讨超声引导下置管引流联合腹腔镜阑尾切除术(LA)在化脓性阑尾炎中的应用价值。方法回顾性分析2019年1月至2023年7月徐州医科大学附属淮安医院收治的37例化脓性阑尾炎患者的临床资料,均先行超声引导下置管引流,待脓腔消失、急性炎... 详细信息

目的探讨超声引导下置管引流联合腹腔镜阑尾切除术(LA)在化脓性阑尾炎中的应用价值。方法回顾性分析2019年1月至2023年7月徐州医科大学附属淮安医院收治的37例化脓性阑尾炎患者的临床资料,均先行超声引导下置管引流,待脓腔消失、急性炎症缓解后行LA。结果37例患者均成功行超声引导下置管引流术,脓腔消失时间(2.95±0.82)d,腹痛消失时间(5.30±0.52)d,体温恢复至正常时间(4.25±1.20)d,白细胞计数恢复至正常时间(7.24±0.43)d,带管时间(7.27±0.96)d,带管期间总引流量(96.76±21.06)mL,LA手术时间(45.54±6.10)min,出血量(23.68±6.66)mL。3例患者因阑尾周围粘连严重而中转为开腹手术,所有患者未出现大出血、肠道损伤等严重并发症。结论超声引导下置管引流联合LA治疗化脓性阑尾炎具有创伤小、安全系数高、并发症少等优点,值得临床推广应用。

关键词：化脓性阑尾炎超声引导下置管引流腹腔镜阑尾切除术

Denoising of seismic data via multi-scale ridgelet transform

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Earthquake Science 2009年第5期22卷 493-498页

作者： Henglei Zhang tianyou liu Yuncui Zhang Institute of Geophysics and Geomatics China University of Geosciences Wuhan 430074 China Key Laboratory of Tectonics andPetroleum Resources (China University of Geosciences) Ministry of Education Wuhan 430074 China The 5th Geophysical Prospecting Brigade Zhongnan Petroleum Bureau Xiangtan 411104 China

Noise has traditionally been suppressed or eliminated in seismic data sets by the use of Fourier filters and, to a lesser degree, nonlinear statistical filters. Although these methods are quite useful under specific conditions, they may produce undesirable effects for the low signal to noise ratio data. In this paper, a new method, multi-scale ridgelet transform, is used in the light of the theory of ridgelet transform. We employ wavelet transform to do sub-band decomposition for the signals and then use non-linear thresholding in ridgelet domain for every block. In other words, it is based on the idea of partition, at sufficiently fine scale, a curving singularity looks straight, and so ridgelet transform can work well in such cases. Applications on both synthetic data and actual seismic data from Sichuan basin, South China, show that the new method eliminates the noise portion of the signal more efficiently and retains a greater amount of geologic data than other methods, the quality and consecutiveness of seismic event are improved obviously as well as the quality of section is improved.

关键词： ridgelet transform multi-scale random noise sub-band decomposition complex Morlet wavelet

Interpretation of the west segment of the coastal fault zone in the coastal region of South China based on the gravity data

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Geodesy and Geodynamics 2018年第2期9卷 142-150页

作者： Lisi Bi Zhenhuan Ren Xiuwei Ye tianyou liu Jihua Qiao Key Laboratory of Earthquake Monitoring and Disaster Mitigation Technology Guangdong Earthquake Administration Guangdong Provincial Key Laboratory of Earthquake Early Warning and Safety Diagnosis of Major Projects China University of Geosciences Development Research Center of China Geological Survey

By systemic processing, comprehensive analysis, and interpretation of gravity data, we confirmed the existence of the west segment of the coastal fault zone(west of Yangjiang to Beibu Bay) in the coastal region of South China. This showed an apparent high gravity gradient in the NEE direction, and worse linearity and less compactness than that in the Pearl River month. This also revealed a relatively large curvature and a complicated gravity structure. In the finding images processed by the gravity data system, each fault was well reflected and primarily characterized by isolines or thick black stripes with a cutting depth greater than 30 km. Though mutually cut by NW-trending and NE-trending faults, the apparent NEE stripe-shaped structure of the west segment of the coastal fault zone remained unchanged,with good continuity and an activity strength higher than that of NW and NE-trending faults. Moreover,we determined that the west segment of the coastal fault zone is the major seismogenic structure responsible for strong earthquakes in the coastal region in the border area of Guangdong, Guangxi, and Hainan.

关键词： Coastal region of South China West segment of the coastal fault zone Gravity data Seismogenic structure

Graph reasoning over explicit semantic relation

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High-Confidence Computing 2024年第2期4卷 136-144页

作者： tianyou Zhu Shi liu Bo Li Junjian liu Pufan liu Fei Zheng State Grid Corporation of China Beijing 100031China

Multi-hop reasoning over language or graphs represents a significant challenge in contemporary research,particularly with the reliance on deep neural *** networks are integral to text reasoning processes,yet they present challenges in extracting and representing domain or commonsense knowledge,and they often lack robust logical reasoning *** address these issues,we introduce an innovative text reasoning *** framework is grounded in the use of a semantic relation graph and a graph neural network,designed to enhance the model’s ability to encapsulate knowledge and facilitate complex multi-hop *** framework operates by extracting knowledge from a broad range of *** constructs a semantic relationship graph based on the logical relationships inherent in the reasoning *** with the core question,the framework methodically deduces key knowledge,using it as a guide to iteratively establish a complete evidence chain,thereby determining the final *** the advanced reasoning capabilities of the graph neural network,this approach is adept at multi-hop logical *** demonstrates strong performance in tasks like machine reading comprehension and question answering,while also clearly delineating the path of logical reasoning.

关键词： Semantic relation graph Multi-hop reasoning Graph neural network

Geophysical Characteristics of Songliao,Bohaiwan and Jianghan Basins,East China

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Journal of Earth Science 1997年第1期16卷 21-24页

作者： liu tianyou Shi XuemingDepartment of Geophysics, China University of Geosciences, Wuhan 430074

ongliao, Bohaiwan and Jianghan basins are typical rift basins in East China, whose geophysical characteristics are described as follows: (1) The trends of the regional gravity and magnetic field are dominantly NNE, which indicates that the fault network of the basement is NNE and NE. (2) The deep gravity anomalies are mirror reflection of the depression areas associating with high heat flow, which can be explained by the uplift of Moho surface in these basins. (3) The crust has twolayer structure consisting of granite and basalt rocks, and there exist highconductivity and lowvelocity layers in the crust and in the upper mantle. (4) The oil and gas enrichments are distinctly related to the degree of the asthenosphere upwelling and crust thinning and high heat flow.

关键词： geophysical characteristics riftdepression basin East China.