期刊文献+
共找到806篇文章
< 1 2 41 >
每页显示 20 50 100
Real-time acquisition of compact volumetric maps
1
作者 周兰凤 Hong Bingrong 《High Technology Letters》 EI CAS 2006年第1期55-57,共3页
Building compact 3D maps of the environment models has become an important research topic. This paper presented an efficient stream decimation algorithm of massive meshes. The algorithm adapted the pre-processing step... Building compact 3D maps of the environment models has become an important research topic. This paper presented an efficient stream decimation algorithm of massive meshes. The algorithm adapted the pre-processing step leading to lower in-corn memory consumption. This algorithm is applied to reconstructing compact terrain with mobile robot, achieving satisfying results. 展开更多
关键词 compact map rEAL-TIME mobile robot
下载PDF
应用卷积神经网络VGG16的星载GNSS-R海冰检测 被引量:1
2
作者 胡媛 华曦帆 +1 位作者 刘卫 江志豪 《遥感信息》 CSCD 北大核心 2024年第2期28-35,共8页
针对全球卫星导航系统反射计(global navigation satellite system-reflection,GNSS-R)海冰检测中延迟-多普勒图(delay-Doppler map,DDM)数据噪声大、消融期精度低等问题,提出将VGG16卷积神经网络模型应用于海冰检测。通过深层的网络结... 针对全球卫星导航系统反射计(global navigation satellite system-reflection,GNSS-R)海冰检测中延迟-多普勒图(delay-Doppler map,DDM)数据噪声大、消融期精度低等问题,提出将VGG16卷积神经网络模型应用于海冰检测。通过深层的网络结构提取DDM多层次特征进行海冰海水分类,以提高海冰检测的精度和稳定性。实验结果表明,与美国国家海洋和大气管理局地表类型数据对比,所提出的基于VGG16海冰检测方法检测准确率为98.02%,有效提升了海冰检测的准确率和稳定性。 展开更多
关键词 海冰遥感 海冰检测 星载GNSS-r 卷积神经网络 延迟-多普勒图 NOAA
下载PDF
FREDHOLM AND COMPACT MAPPINGS SHARING A VALUE
3
作者 J.M.Soriano 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第6期682-686,共5页
Sufficient conditions are given to assert that two differentiable mappings between Banach spaces have common values. The proof is essentially based upon continuation methods.
关键词 zero point continuation methods C 1 HOMOTOPY surjective implicit function theorem compact mapping Fredholm mapping index zero INJECTIVE DIFFEOMOrPHISM
下载PDF
GENERALIZED I-NONEXPANSIVE MAPS AND INVARIANT APPROXIMATION RESULTS IN p-NORMED SPACES 被引量:1
4
作者 N.Hussain 《Analysis in Theory and Applications》 2006年第1期72-80,共9页
Abstract We extend the concept of R-subeommuting maps due to Shahzad to the case of non-starshaped domain and obtain a common fixed point result for this class of maps on non-starshaped domain in the setup of p-norra... Abstract We extend the concept of R-subeommuting maps due to Shahzad to the case of non-starshaped domain and obtain a common fixed point result for this class of maps on non-starshaped domain in the setup of p-norraed spaces. As applications, we establish noncommutative versions of various best approximation results for generalized I-nonexpansive maps on non-starshaped domain. Our results unify and extend that of Al- Thagafi, Dotson, IIabiniak, Jungck and Senna, Latif, Sahab, Khan and Sessa and Shahzad. 展开更多
关键词 common fixed point contractive family of functions r-subcommuting maps invariant approximation
下载PDF
Necessary Conditions for a Fixed Point of Maps in Non-Metric Spaces
5
作者 I. Raykov 《Advances in Pure Mathematics》 2012年第6期371-372,共2页
The main purpose of the present work is to introduce necessary conditions for a map on a non-metric space, defined by using a map on a metric space, to have a fixed point.
关键词 Topological SPACE Complete Metric compact SPACE CAUCHY Sequence LIPSCHITZ Continuous map CONTrACTION map
下载PDF
New Necessary Conditions for a Fixed-Point of Maps in Non-Metric Spaces
6
作者 Ivan Raykov 《Advances in Pure Mathematics》 2022年第10期561-564,共4页
Our purpose is to introduce new necessary conditions for a fixed point of maps on non-metric spaces. We use a contraction map on a metric topological space and a lately published definition of limit of a function betw... Our purpose is to introduce new necessary conditions for a fixed point of maps on non-metric spaces. We use a contraction map on a metric topological space and a lately published definition of limit of a function between the metric topological space and the non-metric topological space. Then we show that we can create a function h on the non-metric space Y, h :Y →Y and present necessary conditions for a fixed point of this map on this map on Y. Therefore, this gives an opportunity to take a best conclusion in some sense, when non-metrizable matter is under consideration. 展开更多
关键词 Topological Space compact Metric Space Fixed Point Contraction map Non-Metric Space
下载PDF
A Note on Topological Entropy of Continuous Self-Maps
7
作者 Zabidin Salleh 《Journal of Mathematics and System Science》 2015年第3期93-99,共7页
Topological entropy can be an indicator of complicated behavior in dynamical systems. It is first introduce by Adler, Konheim and McAndrew by using open covers in 1965. After that it is still an active research by man... Topological entropy can be an indicator of complicated behavior in dynamical systems. It is first introduce by Adler, Konheim and McAndrew by using open covers in 1965. After that it is still an active research by many researchers to produce more properties and applications up to nowadays. The purpose of this paper is to review and explain most important concepts and results of topological entropies of continuous self-maps for dynamical systems on compact and non-compact topological and metric spaces. We give proofs for some of its elementary properties of the topological entropy. Slight modification on Adler's topological entropy is also presented. 展开更多
关键词 Dynamical system topological entropy continuous maps compact space metric space.
下载PDF
NEW FIXED POINT THEOREMS FOR P_1-COMPACT MAPPINGS IN BANACH SPACES
8
作者 Shaoyuan Xu 《Analysis in Theory and Applications》 2007年第3期274-282,共9页
E E. Browder and W. V. Petryshyn defined the topological degree for A- proper mappings and then W. V. Petryshyn studied a class of A-proper mappings, namely, P1-compact mappings and obtained a number of important fixe... E E. Browder and W. V. Petryshyn defined the topological degree for A- proper mappings and then W. V. Petryshyn studied a class of A-proper mappings, namely, P1-compact mappings and obtained a number of important fixed point theorems by virtue of the topological degree theory. In this paper, following W. V. Petryshyn, we continue to study P1-compact mappings and investigate the boundary condition, under which many new fixed point theorems of P1-compact mappings are obtained. On the other hand, this class of A-proper mappings with the boundedness property includes completely continuous operators and so, certain interesting new fixed point theorems for completely continuous operators are obtained immediately. As a result of it, our results generalize several famous theorems such as Leray-Schauder's theorem, Rothe's theorem, Altman's theorem, Petryshyn's theorem, etc. 展开更多
关键词 A-proper mapping P1-compact mapping completely continuous operator topological degree fixed point theorem
下载PDF
ON POINTWISE R-SUBWEAKLY COMMUTING MAPS AND BEST APPROXIMATIONS
9
作者 F. Akbar N. Sultana 《Analysis in Theory and Applications》 2008年第1期40-49,共10页
The main purpose of this paper is to prove some common fixed point theorems for pointwise R-subweakly commuting maps on non-starshaped domains in p-normed spaces and locally convex topological vector spaces. As applic... The main purpose of this paper is to prove some common fixed point theorems for pointwise R-subweakly commuting maps on non-starshaped domains in p-normed spaces and locally convex topological vector spaces. As applications, invariant approximation results are established. This work provides extension as well as substantial improvement of several results in the existing literature. 展开更多
关键词 common fixed point contractive family of functions pointwise r-subweaklycommuting maps invariant approximation
下载PDF
基于R-树索引的Map-Reduce空间连接聚集操作 被引量:5
10
作者 刘义 陈荦 +1 位作者 景宁 熊伟 《国防科技大学学报》 EI CAS CSCD 北大核心 2013年第1期136-141,共6页
空间连接聚集是一种常用并且非常耗时的空间数据库操作,特别是在面对大规模空间数据集时,单机运行环境难以满足其对时空开销的需求,如何设计高效的面向云计算环境中的分布式空间连接聚集算法越来越受到人们关注。Map-Reduce作为云计算... 空间连接聚集是一种常用并且非常耗时的空间数据库操作,特别是在面对大规模空间数据集时,单机运行环境难以满足其对时空开销的需求,如何设计高效的面向云计算环境中的分布式空间连接聚集算法越来越受到人们关注。Map-Reduce作为云计算的核心模式受限于其扁平化的串行扫描操作模型,常被用来加速非索引的空间连接操作,现有工作尚无将Map-Reduce和R-树索引结合来处理空间连接聚集。因此,提出了基于R-树索引的Map-Reduce空间连接聚集算法(RSJA-MR)来更高效地返回连接聚集结果。提出一种分布式R-树索引结构以支持大规模空间数据的索引,RSJA-MR算法利用分布式R-树生成任务集,任务集的执行满足无依赖并行计算模式,很容易在Map-Reduce框架中进行表达。文中提出一种实时缓存策略以支持索引并发访问。实验结果表明:相比非索引的Map-Reduce连接聚集算法,在空间交叠连接聚集查询上,时间性能最少提升8%,在空间包含连接聚集查询上,时间性能最少提升近35%。 展开更多
关键词 云计算 map-rEDUCE 空间连接聚集 r-树
下载PDF
基于ADO.NET的O/R Mapping中间件的研究 被引量:5
11
作者 王丽芳 蒋泽军 +1 位作者 庄亮 曾杰 《西北工业大学学报》 EI CAS CSCD 北大核心 2006年第6期759-762,共4页
目前大多数软件开发都采用面向对象技术,而数据仍然保存在关系数据库中。由于对象模型和关系模型存在阻抗不匹配,因此实现对象与关系的映射已成为软件开发领域的关键问题。采用O/R M app ing(对象/关系映射)技术、XM L技术和软件分层的... 目前大多数软件开发都采用面向对象技术,而数据仍然保存在关系数据库中。由于对象模型和关系模型存在阻抗不匹配,因此实现对象与关系的映射已成为软件开发领域的关键问题。采用O/R M app ing(对象/关系映射)技术、XM L技术和软件分层的设计思想,实现了一个有效的数据库访问中间件,解决了利用ADO.NET开发应用程序遇到的数据表示和存取问题。 展开更多
关键词 数据库访问 阻抗失谐 中间件 对象关系映射 ADO.NET
下载PDF
Grove在O/R Mapping中的应用
12
作者 吴立春 何军 《商场现代化》 北大核心 2007年第12Z期393-395,共3页
本文论述了O/R Mapping的运行机制和在.NET应用程序开发中应用Grove工具如何实现O/R Mapping映射框架。
关键词 Grove O/r mapPING SQL
下载PDF
工作流系统中角色管理的O/R Mapping策略研究 被引量:1
13
作者 刘生福 樊持杰 罗美淑 《微计算机信息》 2010年第9期213-215,共3页
面向对象编程是当前软件开发的主要方法,而关系数据库在短期内有其不可替代的地位,因此,怎样实现对象模型到关系模型的映射就成了软件开发中一个重要的问题。本文结合一个工作流管理系统的开发过程,说明了O/RMapping(Object Relational ... 面向对象编程是当前软件开发的主要方法,而关系数据库在短期内有其不可替代的地位,因此,怎样实现对象模型到关系模型的映射就成了软件开发中一个重要的问题。本文结合一个工作流管理系统的开发过程,说明了O/RMapping(Object Relational Mapping)的映射策略及其在软件开发中的重要性。 展开更多
关键词 面向对象编程 关系数据库管理系统 O/rmapping WFMS
下载PDF
.NET项目中利用LLBLGen实现O/R Mapping
14
作者 王欢燕 龚娟 《电脑知识与技术》 2009年第3X期2161-2162,2168,共3页
该文介绍了在.NET中如何利用LLBLGen工具实现ORMAPPING(即生成持久层),并结合实例给出详细生成过程以及调用示例。
关键词 VS.NET 面向对象 O/r mapping LLBLGen
下载PDF
星载GNSS-R监测海面目标技术进展 被引量:2
15
作者 胡媛 顾世森 +2 位作者 刘卫 江志豪 袁鑫泰 《全球定位系统》 CSCD 2023年第1期125-132,共8页
全球卫星导航系统(GNSS)因其直射信号经海面反射后,反射信号会携带海面物理信息,由此开辟了一种在遥感应用中有巨大潜力的全球卫星导航反射信号(GNSS-R)技术,国内外在星载GNSS-R监测海面领域取得进展.本文总结了应用星载GNSS-R数据监测... 全球卫星导航系统(GNSS)因其直射信号经海面反射后,反射信号会携带海面物理信息,由此开辟了一种在遥感应用中有巨大潜力的全球卫星导航反射信号(GNSS-R)技术,国内外在星载GNSS-R监测海面领域取得进展.本文总结了应用星载GNSS-R数据监测海面目标的进展,然后针对星载GNSS-R监测海面目标技术从最初实验、基于延迟多普勒图(DDM)观测值监测、基于反演散射系数监测、应用神经网络监测四个方面进行了总结和归纳. 展开更多
关键词 全球卫星导航系统(GNSS) 全球卫星导航反射信号(GNSS-r) 延迟多普勒图(DDM) 空间积分法 机器学习
下载PDF
应用MAP技术优化铁路GSM-R网络频率配置的研究
16
作者 薛玲媛 《电子科学技术》 2015年第3期325-328,共4页
本文分析了中国铁路GSM-R网络频率配置的现状。探讨了以MAP技术优化铁路GSM-R网络频率配置的方法。针对GSM-R不同的无线覆盖组网方式——普通单网和冗余覆盖网络,提出了不同的优化方案,以提高铁路GSM-R无线网络的容量。
关键词 map技术 优化 频率配置 GSM-r
下载PDF
磁共振R2*mapping示踪功能型纳米药物载体在NSCLC裸鼠模型的显像研究 被引量:1
17
作者 高鹏 刘于宝 +2 位作者 刘灶松 史长征 罗良平 《中国CT和MRI杂志》 2021年第1期4-7,共4页
目的通过磁共振R2*mapping技术示踪及动态监测NSCLC裸鼠模型给药后不同时间点R2*值的变化趋势,阐明R2*mapping在评价F/A-PLGA@DOX/SPIO纳米载药体系在肿瘤成像中的应用价值及影像学基础。方法成功构建NSCLC裸鼠移植瘤模型24只,随机分为G... 目的通过磁共振R2*mapping技术示踪及动态监测NSCLC裸鼠模型给药后不同时间点R2*值的变化趋势,阐明R2*mapping在评价F/A-PLGA@DOX/SPIO纳米载药体系在肿瘤成像中的应用价值及影像学基础。方法成功构建NSCLC裸鼠移植瘤模型24只,随机分为G1、G2两组,每组12只。分别尾静脉注射单纯SPIO以及F/A-PLGA@DOX/SPIO纳米载药体系,并采用1.5 T MR和动物专用小鼠线圈对建模成功荷瘤裸鼠皮下移植瘤模型进行R2*扫描获得肿瘤区域R2*值。实验结束后全部肿瘤组织及肝脏、脾脏普鲁士蓝染色。结果G2组每个时间点的R2*值均高于G1组(P<0.05)。相对于G1组,G2组肿瘤R2*值在早期上升趋势明显,且在给药后60h时明显高于G1组(P<0.05)。G1组排泄期较G2组明显提前。普鲁士蓝染色结果显示,G2组肿瘤的蓝色铁沉积高于SPIO组,而肝脏、脾脏组织的蓝色铁沉积低于G1。结论R2*值与肿瘤组织内的SPIO含量存在较高敏感性,R2*mapping技术提供了一种SPIO的肿瘤示踪成像方法。 展开更多
关键词 r2*mapping 动态示踪 超顺磁性氧化铁 磁共振成像
下载PDF
The Sequence-covering Compact Images of Paracompact Locally Compact Spaces 被引量:4
18
作者 李进金 李克典 《Northeastern Mathematical Journal》 CSCD 2000年第4期463-468,共6页
This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally... This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally compact metric spaces. 展开更多
关键词 sequence covering mapping compact covering mapping compact mapping quotient mapping paracompact locally compact space cs cover sn cover cs* cover
下载PDF
Adaptive XML to relational mapping: an integrated approach 被引量:3
19
作者 Tian-lei HU Gang CHEN 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第6期758-769,共12页
Storing and querying XML (eXtensible Markup Language) data in relational form can exploit various services offered by modern relational database management systems (RDBMSs). Due to structural complexity of XML, there ... Storing and querying XML (eXtensible Markup Language) data in relational form can exploit various services offered by modern relational database management systems (RDBMSs). Due to structural complexity of XML, there are many equivalent relational mapping schemes for the same XML data and queries. In this paper, we propose the adaptive XML to relational mapping (AX2RM) system, which considers finding optimal XML to relational (X2R) mapping as four separate but correlated procedures: logical database design, data scale estimation, workload transformation, and physical database design. We view the whole process as an autonomic computing problem and formalize the adaptive X2R mapping problem. Search spaces for each procedure are investigated individually, and five approaches for finding the optimal mapping are studied. We propose an integrated approach with greedy pruning (IT-GP), which views the mapping procedures as a whole and exploits heuristic rules in each procedure to prune impossible mappings as early as possible. Evaluation of these approaches shows the validity and high efficiency of IT-GP. 展开更多
关键词 XML XML to relational (X2r mapping Autonomic computing
下载PDF
Weakly R-KKM mappings-intersection theorems and minimax inequalities in topological spaces 被引量:1
20
作者 邓磊 杨明歌 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第1期103-109,共7页
In this paper, we introduce the concepts of weakly R-KKM mappings, R- convex and R-β-quasiconvex in general topological spaces without any convex structure. Relating to these, we obtain an extension to general topolo... In this paper, we introduce the concepts of weakly R-KKM mappings, R- convex and R-β-quasiconvex in general topological spaces without any convex structure. Relating to these, we obtain an extension to general topological spaces of Fan's matching theorem, namely that Lemma 1.2 in this paper. On this basis, two intersection theorems are proved in topological spaces. By using intersection theorems, some minimax inequalities of Ky Fan type are also proved in topological spaces. Our results generalize and improve the corresponding results in the literature. 展开更多
关键词 weakly r-KKM mapping r-convex r-β-quasiconvex generalized r-KKMmapping
下载PDF
上一页 1 2 41 下一页 到第
使用帮助 返回顶部