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全球不同类型大型气藏的开发特征及经验 被引量:50
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作者 贾爱林 闫海军 +2 位作者 郭建林 何东博 魏铁军 《天然气工业》 EI CAS CSCD 北大核心 2014年第10期33-46,共14页
据AAPG的资料,全球已发现的370个大气田集中分布在西西伯利亚盆地、波斯湾盆地、扎格罗斯盆地、卡拉库姆盆地、墨西哥湾盆地、卡那封盆地以及东西伯利亚盆地,分布在上述盆地的大型气藏占总数量的45%,其储量占到大气田储量的68.3%。在分... 据AAPG的资料,全球已发现的370个大气田集中分布在西西伯利亚盆地、波斯湾盆地、扎格罗斯盆地、卡拉库姆盆地、墨西哥湾盆地、卡那封盆地以及东西伯利亚盆地,分布在上述盆地的大型气藏占总数量的45%,其储量占到大气田储量的68.3%。在分析所有大型气藏资料的基础上,研究了大型气藏的数量、储量、地区、地层、圈闭类型、深度、发现时间等特征。依据"实用性、针对性和科学性"分类原则,围绕岩性、厚度、规模、物性、压力、流体等因素将大型气藏划分为5种类型:1厚层整装高渗透砂岩气藏,规模大、储层厚、物性好、或存在边底水;2低渗透砂岩气藏,规模大、物性差、一般不存在边底水;3边底水裂缝型碳酸盐岩气藏,规模大、裂缝发育、存在边底水;4高温、高压、高含硫"三高"气藏;5凝析气藏,压力温度异常、相态复杂、常常发生反凝析现象。厘清大型气藏的分布特征为我国天然气藏的勘探指明了方向,总结出的不同类型大型气藏的开发特征也为相同类型气藏的经济、高效、安全开发提供了宝贵的经验。 展开更多
关键词 全球 大型气藏 分布特征 开发特征 类型 划分原则 勘探方向 高效开发
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High-resolution remote sensing mapping of global land water 被引量:25
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作者 LIAO AnPing CHEN LiJun +6 位作者 CHEN Jun HE ChaoYing CAO Xin CHEN Jin PENG Shu SUN FangDi GONG Peng 《Science China Earth Sciences》 SCIE EI CAS 2014年第10期2305-2316,共12页
Land water, one of the important components of land cover, is the indispensable and important basic information for climate change studies, ecological environment assessment, macro-control analysis, etc. This article ... Land water, one of the important components of land cover, is the indispensable and important basic information for climate change studies, ecological environment assessment, macro-control analysis, etc. This article describes the overall study on land water in the program of global land cover remote sensing mapping. Through collection and processing of Landsat TM/ETM+, China's HJ-1 satellite image, etc., the program achieves an effective overlay of global multi-spectral image of 30 m resolution for two base years, namely, 2000 and 2010, with the image rectification accuracy meeting the requirements of 1:200000 mapping and the error in registration of images for the two periods being controlled within 1 pixel. The indexes were designed and selected reasonably based on spectral features and geometric shapes of water on the scale of 30 m resolution, the water information was extracted in an elaborate way by combining a simple and easy operation through pixel-based classification method with a comprehensive utilization of various rules and knowledge through the object-oriented classification method, and finally the classification results were further optimized and improved by the human-computer interaction, thus realizing high-resolution remote sensing mapping of global water. The completed global land water data results, including Global Land 30-water 2000 and Global Land 30-water 2010, are the classification results featuring the highest resolution on a global scale, and the overall accuracy of self-assessment is 96%. These data are the important basic data for developing relevant studies, such as analyzing spatial distribution pattern of global land water, revealing regional difference, studying space-time fluctuation law, and diagnosing health of ecological environment. 展开更多
关键词 global land cover land surface water 30 m resolution classification method remote sensing mapping
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具有全局特征的空间注意力机制 被引量:9
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作者 张连超 乔瑞萍 +2 位作者 党祺玮 翟沛源 孙红帅 《西安交通大学学报》 EI CAS CSCD 北大核心 2020年第11期129-138,共10页
为了获得卷积神经网络特征图中不同特征点之间的长距离依赖关系,使卷积神经网络更好地区分前景目标和背景信息,提出了一种具有全局特征的空间注意力机制。通过通道融合层将多通道的原始特征图组合成单通道的特征融合图,消除了通道间信... 为了获得卷积神经网络特征图中不同特征点之间的长距离依赖关系,使卷积神经网络更好地区分前景目标和背景信息,提出了一种具有全局特征的空间注意力机制。通过通道融合层将多通道的原始特征图组合成单通道的特征融合图,消除了通道间信息分布对获取空间注意力权重的影响;将特征融合图经过全局特征获取处理,获得能够反映特征融合图中某特征点与特征融合图中所有点之间相关性的全局特征图;全局特征图与初始值为0的可学习变量相乘,并且在通道域复制自身,扩展为原始特征图大小,将扩展后的全局特征图与原始特征图对应元素相加,获得具有注意力机制的特征图。在不同卷积神经网络中加入具有全局特征的空间注意力机制进行实验,结果表明:在脑电波二分类任务中,所提注意力机制的分类准确率最高提升了0.839%;在CIFAR-10数据集多分类任务中,所提注意力机制的分类准确率最高提升了0.484%;在夜间车辆单类别检测中,在交并比阈值大于0.5的平均精度评判标准下,所提注意力机制最高提升了3.860%,在交并比阈值大于0.75的平均精度评判标准下,所提注意力机制最高提升了11.726%;在voc2007数据集多类别检测中,在交并比阈值大于0.5的平均精度评判标准下,所提注意力机制最高提升了0.778%,在交并比阈值大于0.75的平均精度评判标准下,所提注意力机制最高提升了1.232%。 展开更多
关键词 卷积神经网络 空间注意力机制 全局特征 特征融合 目标分类 目标检测
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全域旅游产业统计分类与指标体系构建 被引量:8
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作者 李冬 《统计与决策》 CSSCI 北大核心 2019年第14期32-36,共5页
旅游产业分类是旅游产业核算的前提和基础。文章从全域旅游发展的视角,结合旅游产业融合和跨界发展的现状,通过研究2018年旅游产业分类标准及理论依据,分析旅游统计指标合理框架,提出了规模指标、质量指标和贡献度指标三个系列的指标体系。
关键词 全域旅游 统计分类 统计指标
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基于气候区的全球干旱形势分析 被引量:8
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作者 吴陶樱 方秀琴 +2 位作者 吴小君 杜晓彤 汪伟 《水土保持研究》 CSCD 北大核心 2019年第3期166-173,共8页
使用Mann-Kendall趋势检验方法对过去三十多年间全球陆地和各气候区的干旱变化进行了分析,得到了全球陆地和各气候区内的干旱变化情况。结果表明:在干旱发生影响范围上,湿润地区的影响范围更大,而在干旱发生的频率上,干旱半干旱地区的... 使用Mann-Kendall趋势检验方法对过去三十多年间全球陆地和各气候区的干旱变化进行了分析,得到了全球陆地和各气候区内的干旱变化情况。结果表明:在干旱发生影响范围上,湿润地区的影响范围更大,而在干旱发生的频率上,干旱半干旱地区的频率更高。同时,热带季风气候区、热带稀树草原气候区、沙漠气候区、湿润亚热带气候区和海洋性气候区干旱面积有显著变大趋势,全球陆地、湿润大陆性气候区、亚寒带气候区和苔原气候区干旱面积有显著变小趋势。文章又对过去三十多年间全球和各气候区的变干趋势和变湿趋势进行了研究,发现全球20%以上的陆地有显著变干趋势,20%以上的陆地有显著变湿趋势,其中热带季风气候区和热带稀树草原气候区有40%以上面积有显著变干趋势,亚寒带气候区和苔原气候区有40%以上面积有显著变湿趋势。 展开更多
关键词 全球干旱 气候分区 MANN-KENDALL检验 SPI
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全球精密锻造技术专利布局与发展态势
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作者 陈勇棠 张伶俐 《锻压技术》 CAS CSCD 北大核心 2024年第4期15-25,共11页
精密锻造是大国间较量的必争之技,以22035件全球专利为依据,分析了该技术的全球专利布局及技术发展。全球精密锻造技术专利整体呈现快速上涨趋势,技术周期处于技术成长期;中国是最大的目标市场、最多的原创专利来源国;美国专利申请人的... 精密锻造是大国间较量的必争之技,以22035件全球专利为依据,分析了该技术的全球专利布局及技术发展。全球精密锻造技术专利整体呈现快速上涨趋势,技术周期处于技术成长期;中国是最大的目标市场、最多的原创专利来源国;美国专利申请人的全球布局意识最强,原创专利流向全球的范围最广;技术结构主要集中在IPC小类B21J、B21K和C22C等,中国覆盖的技术领域范围最广,优势领域在F16P、B08B等,F02B存在短板;日本企业的研发实力最强、高价值专利数量最多。我国应优化专利结构、提高专利质量,增强全球布局,扩大重点技术领域的领先优势,补齐技术短板,提高专利技术的成果化、资本化和产业化。 展开更多
关键词 精密锻造 专利 厚创专利 全球布局 IPC分类
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NDVI时间序列在全球耕地提取中的应用 被引量:6
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作者 何超英 廖安平 +1 位作者 陈志刚 陈利军 《地理信息世界》 2013年第2期66-69,88,共5页
针对全球范围内只能依据单季相Landsat影像数据提取耕地的现状,在现有基于影像光谱与纹理特征的监督分类方法基础上,引入NDVI时间序列数据,解决部分单季相影像造成的耕地与其他类型的混分问题。实验表明,利用NDVI时间序列数据能有效地... 针对全球范围内只能依据单季相Landsat影像数据提取耕地的现状,在现有基于影像光谱与纹理特征的监督分类方法基础上,引入NDVI时间序列数据,解决部分单季相影像造成的耕地与其他类型的混分问题。实验表明,利用NDVI时间序列数据能有效地反映耕地的物候特征,弥补使用单季相Landsat影像提取耕地的缺陷,较好地完善全球耕地的提取方案,提高了耕地提取精度。 展开更多
关键词 全球耕地 影像分类 NDVI时间序列
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Relationship of the preoperative NRS 2002 score,PG-SGA score,and serum indices with postoperative complications in patients with gastric cancer 被引量:6
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作者 Dao Lai Huang Xiang Hua Wu +7 位作者 Chang Li Wang Jun Qiang Chen Kui Jia Jing Zhou Li Sheng Lu Yong Sheng Zhang Jing Jin Ke Ke Huang 《Journal of Nutritional Oncology》 2021年第2期74-80,共7页
Objective To examine the utility of the Nutrition Risk Screening 2002(NRS 2002),Patient-Generated Subjective Global Assessment(PG-SGA)and serum factors for the preoperative evaluation of gastric cancer patients.Method... Objective To examine the utility of the Nutrition Risk Screening 2002(NRS 2002),Patient-Generated Subjective Global Assessment(PG-SGA)and serum factors for the preoperative evaluation of gastric cancer patients.Methods We examined 181 gastric cancer patients treated at the First Affiliated Hospital of Guangxi Medical University from January 2015 to January 2018.Nutritional assessments were administered within 48 h of admission.The body mass index(BMI)and serum factors were measured,and information on preoperative nutritional support and postoperative complications was recorded.Results Both the NRS 2002 and PG-SGA had positive correlations with age(P<0.05),and negative correlations with albumin,prealbumin,transferrin,hemoglobin,BMI,and bodyweight(P<0.05).The NRS 2002 and PG-SGA scores were positively correlated with each other(r=0.683,P<0.01),but had poor consistency(κ=0.357,P<0.01).During the preoperative period,33.2%of patients received nutritional support,mainly enteral nutrition.The nutritional risk group(NRS 2002≥3)received more support than the group without nutritional risk(NRS 2002<3;P<0.05).Patients with nutritional risk or malnutrition who received preoperative nutritional support had fewer postoperative complications than unsupported patients.The overall rate of complications was 12.2%,and the rate of severe complications(gradeⅢor above)was 5.5%.The malnutrition and nutritional risk groups had higher rates of severe complications.Conclusions The combined application of the NRS 2002,PG-SGA,BMI,and serum nutritional indices was useful for the nutritional screening and assessment of preoperative gastric cancer patients.The NRS 2002 and PG-SGA provided guidance on the need for nutritional support during the preoperative period. 展开更多
关键词 Nutritional risk screening 2002 Patient-Generated Subjective global Assessment Gastric cancer Serum biochemical indices Clavien-Dindo classification
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Modelling analysis embodies drastic transition among global potential natural vegetations in face of changing climate
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作者 Zhengchao Ren Lei Liu +1 位作者 Fang Yin Xiaoni Liu 《Forest Ecosystems》 SCIE CSCD 2024年第2期184-192,共9页
Potential natural vegetation(PNV)is a valuable reference for ecosystem renovation and has garnered increasing attention worldwide.However,there is limited knowledge on the spatio-temporal distributions,transitional pr... Potential natural vegetation(PNV)is a valuable reference for ecosystem renovation and has garnered increasing attention worldwide.However,there is limited knowledge on the spatio-temporal distributions,transitional processes,and underlying mechanisms of global natural vegetation,particularly in the case of ongoing climate warming.In this study,we visualize the spatio-temporal pattern and inter-transition procedure of global PNV,analyse the shifting distances and directions of global PNV under the influence of climatic disturbance,and explore the mechanisms of global PNV in response to temperature and precipitation fluctuations.To achieve this,we utilize meteorological data,mainly temperature and precipitation,from six phases:the Last Inter-Glacial(LIG),the Last Glacial Maximum(LGM),the Mid Holocene(MH),the Present Day(PD),2030(20212040)and 2090(2081–2100),and employ a widely-accepted comprehensive and sequential classification sy–stem(CSCS)for global PNV classification.We find that the spatial patterns of five PNV groups(forest,shrubland,savanna,grassland and tundra)generally align with their respective ecotopes,although their distributions have shifted due to fluctuating temperature and precipitation.Notably,we observe an unexpected transition between tundra and savanna despite their geographical distance.The shifts in distance and direction of five PNV groups are mainly driven by temperature and precipitation,although there is heterogeneity among these shifts for each group.Indeed,the heterogeneity observed among different global PNV groups suggests that they may possess varying capacities to adjust to and withstand the impacts of changing climate.The spatio-temporal distributions,mutual transitions and shift tendencies of global PNV and its underlying mechanism in face of changing climate,as revealed in this study,can significantly contribute to the development of strategies for mitigating warming and promoting re-vegetation in degraded regions worldwide. 展开更多
关键词 Potential natural vegetation global warming Vegetation classification Predicted model CSCS
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全局采样空间注意力机制及其在图像分类与小目标检测识别中的应用
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作者 卢镜宇 张海洋 +1 位作者 王文鑫 赵长明 《激光与光电子学进展》 CSCD 北大核心 2024年第10期396-407,共12页
注意力机制的出现和应用在一定程度上改善了神经网络对全局信息应用不足的缺陷,但常见的注意力机制模块也同样存在感受野小无法关注全局信息的问题,而某些全局注意力机制模块则计算成本过高。为此,提出一种基于卷积、池化、对比方法的... 注意力机制的出现和应用在一定程度上改善了神经网络对全局信息应用不足的缺陷,但常见的注意力机制模块也同样存在感受野小无法关注全局信息的问题,而某些全局注意力机制模块则计算成本过高。为此,提出一种基于卷积、池化、对比方法的轻量化注意力模块,即全局采样空间注意力模块。对于深度网络推理过程中部分模块输出的中间特征图,该注意力模块通过对比差值的形式获取所需要的空间注意力图。全局采样空间注意力模块是一种轻量化的通用模块,能够直接置入卷积神经网络中,增加的成本几乎可以忽略不计,并且其能够与网络一同进行端到端训练。主要在随机抽取的部分ImageNet-1K数据集和团队自制的“低慢小”无人机数据集中对模块进行了验证。实验结果显示,相比其他模块,所提模块在图像分类和小目标检测识别任务中具备1百分点~3百分点的性能提升效果,证明了所提模块的性能与其在小目标检测方面的适用性。 展开更多
关键词 注意力机制 全局采样 轻量化 图像分类 小目标探测
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皖北矿区回采巷道动态权值分类及其差异化支护 被引量:5
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作者 李迎富 华心祝 +1 位作者 王晓虎 杨科 《采矿与安全工程学报》 EI CSCD 北大核心 2017年第6期1042-1050,共9页
皖北矿区回采巷道支护设计很大程度上依赖于技术人员的工程判断力和实践经验,导致有些巷道支护效果不佳,有些设计参数偏于保守,制约着矿井安全高效水平的提高。因此,在考虑层位岩性、节理裂隙、开采深度等因素基础上,定义了巷道顶板、... 皖北矿区回采巷道支护设计很大程度上依赖于技术人员的工程判断力和实践经验,导致有些巷道支护效果不佳,有些设计参数偏于保守,制约着矿井安全高效水平的提高。因此,在考虑层位岩性、节理裂隙、开采深度等因素基础上,定义了巷道顶板、底板及煤帮的稳定性判别指标。基于关键层理论,计算出顶板垮断极限层的层序数和采空区悬顶长度,推导出临界煤柱宽度计算式,从而确定了护巷煤柱稳定性判别指标,并进行了巷道围岩综合评价和整体分类。采用计算机数值模拟,拟合出分类指标与围岩塑性率的函数关系,计算了随围岩条件动态变化的分类指标权值,并依据基本顶来压当量及围岩塑性率函数的斜率变化,确定了围岩次分类的判别条件。结合皖北矿区回采巷道支护的成功实例,构建了包含巷道围岩力学参数、支护参数及其支护效果等信息的样本数据库,在综合考虑巷道类型及服务年限、区域类型、整体分类及围岩次分类基础上,优选试验巷道的支护方案,实现回采巷道支护决策安全可靠、经济合理。 展开更多
关键词 层位岩性 临界煤柱宽度 整体分类 围岩塑性率 动态权值 围岩次分类 差异化支护
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Joint global constraint and Fisher discrimination based multi-layer dictionary learning for image classification
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作者 Peng Hong Liu Yaozong 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2023年第5期1-10,共10页
A multi-layer dictionary learning algorithm that joints global constraints and Fisher discrimination(JGCFD-MDL)for image classification tasks was proposed.The algorithm reveals the manifold structure of the data by le... A multi-layer dictionary learning algorithm that joints global constraints and Fisher discrimination(JGCFD-MDL)for image classification tasks was proposed.The algorithm reveals the manifold structure of the data by learning the global constraint dictionary and introduces the Fisher discriminative constraint dictionary to minimize the intra-class dispersion of samples and increase the inter-class dispersion.To further quantify the abstract features that characterize the data,a multi-layer dictionary learning framework is constructed to obtain high-level complex semantic structures and improve image classification performance.Finally,the algorithm is verified on the multi-label dataset of court costumes in the Ming Dynasty and Qing Dynasty,and better performance is obtained.Experiments show that compared with the local similarity algorithm,the average precision is improved by 3.34%.Compared with the single-layer dictionary learning algorithm,the one-error is improved by 1.00%,and the average precision is improved by 0.54%.Experiments also show that it has better performance on general datasets. 展开更多
关键词 global similarity Fisher discrimination joint local-constraint and Fisher discrimination based dictionary learning(JLCFDDL) joint global constraint and Fisher discrimination based multi-layer dictionary learning image classification
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Innovative Analysis Ready Data(ARD)product and process requirements,software system design,algorithms and implementation at the midstream as necessary-but-notsuffcient precondition of the downstream in a new notion of Space Economy 4.0-Part 1:Problem background in Artificial General Intelligence(AGI)
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作者 Andrea Baraldi Luca D.Sapia +3 位作者 Dirk Tiede Martin Sudmanns Hannah L.Augustin Stefan Lang 《Big Earth Data》 EI CSCD 2023年第3期455-693,共239页
Aiming at the convergence between Earth observation(EO)Big Data and Artificial General Intelligence(AGI),this two-part paper identifies an innovative,but realistic EO optical sensory imagederived semantics-enriched An... Aiming at the convergence between Earth observation(EO)Big Data and Artificial General Intelligence(AGI),this two-part paper identifies an innovative,but realistic EO optical sensory imagederived semantics-enriched Analysis Ready Data(ARD)productpair and process gold standard as linchpin for success of a new notion of Space Economy 4.0.To be implemented in operational mode at the space segment and/or midstream segment by both public and private EO big data providers,it is regarded as necessarybut-not-sufficient“horizontal”(enabling)precondition for:(I)Transforming existing EO big raster-based data cubes at the midstream segment,typically affected by the so-called data-rich information-poor syndrome,into a new generation of semanticsenabled EO big raster-based numerical data and vector-based categorical(symbolic,semi-symbolic or subsymbolic)information cube management systems,eligible for semantic content-based image retrieval and semantics-enabled information/knowledge discovery.(II)Boosting the downstream segment in the development of an ever-increasing ensemble of“vertical”(deep and narrow,user-specific and domain-dependent)value–adding information products and services,suitable for a potentially huge worldwide market of institutional and private end-users of space technology.For the sake of readability,this paper consists of two parts.In the present Part 1,first,background notions in the remote sensing metascience domain are critically revised for harmonization across the multidisciplinary domain of cognitive science.In short,keyword“information”is disambiguated into the two complementary notions of quantitative/unequivocal information-as-thing and qualitative/equivocal/inherently ill-posed information-as-data-interpretation.Moreover,buzzword“artificial intelligence”is disambiguated into the two better-constrained notions of Artificial Narrow Intelligence as part-without-inheritance-of AGI.Second,based on a betterdefined and better-understood vocabulary of multidisciplinary terms,existing EO 展开更多
关键词 Artificial Narrow Intelligence big data cognitive science computer vision Earth observation essential climate variables global Earth Observation System of(component)Systems inductive/deductive/hybrid inference Scene classification Map Space Economy 4.0 radiometric corrections of optical imagery from atmospheric topographic adjacency and bidirectional reflectance distribution function effects semantic content-based image retrieval 2D spatial topology-preserving/retinotopic image mapping world ontology(synonym for conceptual/mental/perceptual model of the world)
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Using Landsat images to monitor changes in the snow-covered area of selected glaciers in northern Pakistan 被引量:4
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作者 Chaman GUL KANG Shi-chang +3 位作者 Badar GHAURI Mateeul HAQ Sher MUHAMMAD Shaukat ALI 《Journal of Mountain Science》 SCIE CSCD 2017年第10期2013-2027,共15页
Landsat satellite images were used to map and monitor the snow-covered areas of four glaciers with different aspects(Passu: 36.473°N, 74.766°E;Momhil: 36.394°N, 75.085°E; Trivor: 36.249°N,74.9... Landsat satellite images were used to map and monitor the snow-covered areas of four glaciers with different aspects(Passu: 36.473°N, 74.766°E;Momhil: 36.394°N, 75.085°E; Trivor: 36.249°N,74.968°E; and Kunyang: 36.083°N, 75.288°E) in the upper Indus basin, northern Pakistan, from 1990-2014. The snow-covered areas of the selected glaciers were identified and classified using supervised and rule-based image analysis techniques in three different seasons. Accuracy assessment of the classified images indicated that the supervised classification technique performed slightly better than the rule-based technique. Snow-covered areas on the selected glaciers were generally reduced during the study period but at different rates. Glaciers reached maximum areal snow coverage in winter and premonsoon seasons and minimum areal snow coverage in monsoon seasons, with the lowest snow-covered area occurring in August and September. The snowcovered area on Passu glacier decreased by 24.50%,3.15% and 11.25% in the pre-monsoon, monsoon and post-monsoon seasons, respectively. Similarly, the other three glaciers showed notable decreases in snow-covered area during the pre-and post-monsoon seasons; however, no clear changes were observed during monsoon seasons. During pre-monsoon seasons, the eastward-facing glacier lost comparatively more snow-covered area than the westward-facing glacier. The average seasonal glacier surface temperature calculated from the Landsat thermal band showed negative correlations of-0.67,-0.89,-0.75 and-0.77 with the average seasonal snowcovered areas of the Passu, Momhil, Trivor and Kunyang glaciers, respectively, during pre-monsoon seasons. Similarly, the air temperature collected from a nearby meteorological station showed an increasing trend, indicating that the snow-covered area reduction in the region was largely due to climate warming. 展开更多
关键词 Snow-covered area Glacier global warming classification technique Northern Pakistan
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基于改进深度学习的图像敏感信息识别研究
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作者 李选臣 《自动化与仪器仪表》 2023年第10期36-39,44,共5页
对网站图像敏感信息识别检测问题,提出一种基于改进深度学习的图像敏感信息识别方法。通过特征融合网络,将经全局优化后的区域检测网络与全局识别网络提取特征相融合,并引入注意力机制,对图像中包含敏感部位的区域进行加权聚焦,提高模... 对网站图像敏感信息识别检测问题,提出一种基于改进深度学习的图像敏感信息识别方法。通过特征融合网络,将经全局优化后的区域检测网络与全局识别网络提取特征相融合,并引入注意力机制,对图像中包含敏感部位的区域进行加权聚焦,提高模型检测效率和准确性。实验证明,采用通过全局特征优化后的区域检测网络,平均检测精度提高1%,相较于SSD、Faster R-CNN等目标生成网络,平均检测精度高8.54%与10.63%,提取结果更精准;融合局部特征的全局识别网络,识别精度随着局部特征提取准确度上升而上升,当提取种类到达10种时,识别精度比未加入高1.8%;通过引入注意力机制,本模型检测准确率提升明显,当聚焦点数为7时,比未引入高0.7%;最终,相较于未包含局部特征的ResNet50网络、虽然未包含局部特征但结构更复杂的ResNet101网络,与虽然考虑局部特征,但未与全局特征进行融合的DMCNet网络,本模型检测准确率平均高出3.25%、2.15%和6%,且耗费时间较短,具有更高的鉴别力和检测效率。 展开更多
关键词 图像识别 区域检测 全局分类 注意力机制 特征融合
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Analysis of the trend of global power sources based on comment emotion mining 被引量:3
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作者 Shengxiang Zhang Chao Shi +2 位作者 Xin Jiang Ying Zhang Lu Zhang 《Global Energy Interconnection》 2020年第3期283-291,共9页
In recent years,renewable energy technologies have been developed vigorously,and related supporting policies have been issued.The developmental trend of different energy sources directly affects the future development... In recent years,renewable energy technologies have been developed vigorously,and related supporting policies have been issued.The developmental trend of different energy sources directly affects the future developmental pattern of the energy and power industry.Energy trend research can be quantified through data statistics and model calculations;however,parameter settings and optimization are difficult,and the analysis results sometimes do not reflect objective reality.This paper proposes an energy and power information analysis method based on emotion mining.This method collects energy commentary news and literature reports from many authoritative media around the world and builds a convolutional neural network model and a text analysis model for topic classification and positive/negative emotion evaluation,which helps obtain text evaluation matrixes for all collected texts.Finally,a long-short-term memory model algorithm is employed to predict the future development prospects and market trends for various types of energy based on the analyzed emotions in different time spans.Experimental results indicate that energy trend analysis based on this method is consistent with the real scenario,has good applicability,and can provide a useful reference for the development of energy and power resources and of other industry areas as well. 展开更多
关键词 global energy and power trend Topic classification Text emotion analysis CNN LSTM
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Hooke and Jeeves algorithm for linear support vector machine 被引量:1
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作者 Yeqing Liu Sanyang Liu Mingtao Gu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第1期138-141,共4页
Coordinate descent method is a unconstrained optimization technique. When it is applied to support vector machine (SVM), at each step the method updates one component of w by solving a one-variable sub-problem while... Coordinate descent method is a unconstrained optimization technique. When it is applied to support vector machine (SVM), at each step the method updates one component of w by solving a one-variable sub-problem while fixing other components. All components of w update after one iteration. Then go to next iteration. Though the method converges and converges fast in the beginning, it converges slow for final convergence. To improve the speed of final convergence of coordinate descent method, Hooke and Jeeves algorithm which adds pattern search after every iteration in coordinate descent method was applied to SVM and a global Newton algorithm was used to solve one-variable subproblems. We proved the convergence of the algorithm. Experimental results show Hooke and Jeeves' method does accelerate convergence specially for final convergence and achieves higher testing accuracy more quickly in classification. 展开更多
关键词 support vector machine classification pattern search Hooke and Jeeves coordinate descent global Newton algorithm.
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平面四次齐次系统的全局拓扑分类及其系数条件 被引量:2
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作者 马少军 王健 《山东师范大学学报(自然科学版)》 CAS 2003年第2期13-16,共4页
讨论了平面四次齐次微分系统的全局拓扑结构 。
关键词 平面四次齐次微分系统 全局拓扑结构 拓扑分类 系数条件 极限环 相图
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局部核方法及其应用 被引量:1
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作者 万海平 何华灿 周延泉 《山东大学学报(理学版)》 CAS CSCD 北大核心 2006年第3期60-62,共3页
核方法是机器学习中一种强有力的学习算法.多个领域的实践表明,通过将领域知识嵌入到核函数中,一般会得到比较好的学习效果.从微分流形的观点讨论了机器学习中全局信息与局部信息的关系,并提出了一种嵌入局部有意义信息的核方法.文本分... 核方法是机器学习中一种强有力的学习算法.多个领域的实践表明,通过将领域知识嵌入到核函数中,一般会得到比较好的学习效果.从微分流形的观点讨论了机器学习中全局信息与局部信息的关系,并提出了一种嵌入局部有意义信息的核方法.文本分类的实验结果表明,与其它几个分类算法相比,它具有较高的性能. 展开更多
关键词 核方法 文本分类 全局观点 局部拟和 人脸识别
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演化算法中一种基于单分类的预选择策略 被引量:1
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作者 张晋媛 周爱民 张桂戌 《计算机学报》 EI CSCD 北大核心 2020年第2期233-249,共17页
演化算法中,预选择算子用于为后续的环境选择过程筛选出好的潜在候选后代解.现有预选择算子大多基于适应值评估、代理模型或分类模型.由于预选择过程本质上是一个分类过程,因此基于分类的预选择过程天然适用于演化算法.先前研究工作采... 演化算法中,预选择算子用于为后续的环境选择过程筛选出好的潜在候选后代解.现有预选择算子大多基于适应值评估、代理模型或分类模型.由于预选择过程本质上是一个分类过程,因此基于分类的预选择过程天然适用于演化算法.先前研究工作采用二分类或多分类模型进行预选择,需预先准备“好”和“差”两组或具有区分性的多组训练样本来构建分类模型,而随着演化算法的执行,“好”解和“差”解之间的界限将愈加模糊,因此准备具有区分性的两组或多组训练样本将变得具有挑战性.为解决该问题,本文提出了一种基于单分类的预选择策略(One-class Classification based PreSelection,OCPS),首先将当前种群中的解均视为“好”类样本,之后只利用该类“好”样本构建单分类模型,然后利用构建的模型对产生的多个候选解进行标记与选择.提出的策略应用在三个代表性演化算法中,数值实验结果表明,提出的策略能够提升现有演化算法的收敛速度. 展开更多
关键词 全局优化 演化算法 分类 单分类 预选择
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