期刊文献+
共找到726篇文章
< 1 2 37 >
每页显示 20 50 100
Construction of Forestry Map Symbol Library and Symbolization Execution Based on MapGIS K9
1
作者 司瑶 武红敢 《Agricultural Science & Technology》 CAS 2010年第11期176-179,共4页
In order to improve the cartography efficiency and the intelligent level of forestry map,we put forward the symbolization scheme of forestry map based on MapGIS K9 platform.Firstly,the symbol library of forestry map w... In order to improve the cartography efficiency and the intelligent level of forestry map,we put forward the symbolization scheme of forestry map based on MapGIS K9 platform.Firstly,the symbol library of forestry map was constructed according to The Graphic Representation of Forestry Map which was issued by the National Forestry Bureau in October,2010.Then,the symbol configuration rule database was established to realize the expression of symbol configuration rule in the digital environment.Finally,the symbolization module was realized with the support of MapGIS Objects component development technology,and the thematic data of forestry were visualized according to the symbol configuration rule.The practice proved that the scheme could basically satisfy the cartography requirements of common forestry maps which included the forest management inventory map. 展开更多
关键词 Forestry map mapGIS K9 map symbol library symbolIZATION
下载PDF
An Anti-aliasing Algorithm Suitable to Map Publishing Symbol
2
作者 DENG Shujun 《Geo-Spatial Information Science》 2006年第3期210-215,共6页
On the basis of analysis of various algorithms, an anti-aliasing algorithm called brush method was presented, which is suitable to map publishing symbol. After introducing the basic principle and implementation of bru... On the basis of analysis of various algorithms, an anti-aliasing algorithm called brush method was presented, which is suitable to map publishing symbol. After introducing the basic principle and implementation of brush method in detail, the result and efficiency were evaluated through experiments. 展开更多
关键词 ALIASING ANTI-ALIASING map publishing symbol brush method RESOLUTION
下载PDF
Studies of phase return map and symbolic dynamics in a periodically driven Hodgkin–Huxley neuron
3
作者 丁炯 张宏 +1 位作者 童勤业 陈琢 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第2期161-167,共7页
How neuronal spike trains encode external information is a hot topic in neurodynamics studies. In this paper, we investigate the dynamical states of the Hodgkin-Huxley neuron under periodic forcing. Depending on the p... How neuronal spike trains encode external information is a hot topic in neurodynamics studies. In this paper, we investigate the dynamical states of the Hodgkin-Huxley neuron under periodic forcing. Depending on the parameters of the stimulus, the neuron exhibits periodic, quasiperiodic and chaotic spike trains. In order to analyze these spike trains quantitatively, we use the phase return map to describe the dynamical behavior on a one-dimensional (1D) map. According to the monotonicity or discontinuous point of the 1D map, the spike trains are transformed into symbolic sequences by implementing a coarse-grained algorithm -- symbolic dynamics. Based on the ordering rules of symbolic dynamics, the parameters of the external stimulus can be measured in high resolution with finite length symbolic sequences. A reasonable explanation for why the nervous system can discriminate or cognize the small change of the external signals in a short time is also presented. 展开更多
关键词 Hodgkin-Huxley neuron return map symbolic dynamics CHAOS
下载PDF
Algorithm of symbol generation and configuration of land polygons in present land-use map
4
作者 ZUO Xiao-qing, NIE Jun-tang Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China 《中国有色金属学会会刊:英文版》 CSCD 2011年第S3期743-747,共5页
The symbolization of land polygon is an important part of cartography. In the mapping of traditional present land-use maps, the symbol of land polygons was usually filled by the method of filling or plotting, but thes... The symbolization of land polygon is an important part of cartography. In the mapping of traditional present land-use maps, the symbol of land polygons was usually filled by the method of filling or plotting, but these methods can't solve the spatial conflicts of the symbol. According to the principle of cartography, the rule of how to symbolize the land polygon was summarized, and a new method that can generate and deploy the land symbols was presented. By making use of C# programming language and Arc Engine developing components, the algorithm can generate land symbols presenting triangle and adjust the coordinate of the symbol. Through mapping the present land-use map of Honghe county, this algorithm can reduce 88.84% of the spatial conflicts error rate compared with the traditional methods. It improves the accuracy and efficiency of the map symbolic. 展开更多
关键词 LAND symbol PRESENT LAND use map symbol CONFIGURATION spatial conflict
下载PDF
Symbolic dynamics of Belykh-type maps
5
作者 Denghui LI Jianhua XIE 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第5期671-682,共12页
The symbolic dynamics of a Belykh-type map (a two-dimensional discon- tinuous piecewise linear map) is investigated. The admissibility condition for symbol sequences named the pruning front conjecture is proved unde... The symbolic dynamics of a Belykh-type map (a two-dimensional discon- tinuous piecewise linear map) is investigated. The admissibility condition for symbol sequences named the pruning front conjecture is proved under a hyperbolicity condition. Using this result, a symbolic dynamics model of the map is constructed according to its pruning front and primary pruned region. Moreover, the boundary of the parameter region in which the map is chaotic of a horseshoe type is given. 展开更多
关键词 discontinuous piecewise linear map symbolic dynamics pruning front primary pruned region HORSESHOE
下载PDF
Enhanced cooperative packet retransmission employing joint cooperative diversity and symbol mapping diversity
6
作者 Wei JI Bao-yu ZHENG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第8期1090-1098,共9页
A joint cooperation diversity and symbol mapping diversity (SMD) strategy is proposed for cooperative packet retransmission system with high-order modulation such as 16QAM. Substantial SER/BER (symbol error rate/bit e... A joint cooperation diversity and symbol mapping diversity (SMD) strategy is proposed for cooperative packet retransmission system with high-order modulation such as 16QAM. Substantial SER/BER (symbol error rate/bit error rate) gains result from multiple packet transmissions over independent paths and distinct bit-to-symbol mappings for each packet transmis-sion. The SER/BER performance of relay assisted retransmission system is analyzed. Simulation results show that the joint-diversity strategy can provide more BER gains than other relaying strategies (i.e., decode-and-forward and constellation rearrangement relaying strategies) when no relay makes a decision error; but if some relays make decision errors, the joint-di-versity strategy outperforms other relaying strategies only when the relays are closer to the source than to the destination. 展开更多
关键词 Cooperative retransmission Hybrid automatic repeat request (HARQ) Cooperative diversity symbol mapping diversity (SMD)
下载PDF
A method of estimating initial conditions of coupled map lattices based on time-varying symbolic dynamics
7
作者 沈民奋 刘英 林兰馨 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第5期1761-1768,共8页
A novel computationally efficient algorithm in terms of the time-varying symbolic dynamic method is proposed to estimate the unknown initial conditions of coupled map lattices (CMLs). The presented method combines s... A novel computationally efficient algorithm in terms of the time-varying symbolic dynamic method is proposed to estimate the unknown initial conditions of coupled map lattices (CMLs). The presented method combines symbolic dynamics with time-varying control parameters to develop a time-varying scheme for estimating the initial condition of multi-dimensional spatiotemporal chaotic signals. The performances of the presented time-varying estimator in both noiseless and noisy environments are analysed and compared with the common time-invariant estimator. Simulations are carried out and the obtained results show that the proposed method provides an efficient estimation of the initial condition of each lattice in the coupled system. The algorithm cannot yield an asymptotically unbiased estimation due to the effect of the coupling term, but the estimation with the time-varying algorithm is closer to the Cramer-Rao lower bound (CRLB) than that with the time-invariant estimation method, especially at high signal-to-noise ratios (SNRs). 展开更多
关键词 coupled map lattices symbolic dynamics initial condition estimation
下载PDF
A method of recovering the initial vectors of globally coupled map lattices based on symbolic dynamics
8
作者 孙丽莎 康晓云 +1 位作者 张琼 林兰馨 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第12期152-159,共8页
Based on symbolic dynamics, a novel computationally efficient algorithm is proposed to estimate the unknown initial vectors of globally coupled map lattices (CMLs). It is proved that not all inverse chaotic mapping ... Based on symbolic dynamics, a novel computationally efficient algorithm is proposed to estimate the unknown initial vectors of globally coupled map lattices (CMLs). It is proved that not all inverse chaotic mapping functions are satisfied for contraction mapping. It is found that the values in phase space do not always converge on their initial values with respect to sufficient backward iteration of the symbolic vectors in terms of global convergence or divergence (CD). Both CD property and the coupling strength are directly related to the mapping function of the existing CML. Furthermore, the CD properties of Logistic, Bernoulli, and Tent chaotic mapping functions are investigated and compared. Various simulation results and the performances of the initial vector estimation with different signal-to- noise ratios (SNRs) are also provided to confirm the proposed algorithm. Finally, based on the spatiotemporal chaotic characteristics of the CML, the conditions of estimating the initial vectors usiug symbolic dynamics are discussed. The presented method provides both theoretical and experimental results for better understanding and characterizing the behaviours of spatiotemporal chaotic systems. 展开更多
关键词 coupled map lattices symbolic dynamics initial condition estimation convergence ordivergence property
下载PDF
On new chaotic mappings in symbol space
9
作者 Inese Bula Jnis Buls Irita Rumbeniece 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第1期114-118,共5页
A well known chaotic mapping in symbol space is a shift mapping.However,other chaotic mappings in symbol space exist too.The basic change is to consider the process not only at a set of times which are equally spaced,... A well known chaotic mapping in symbol space is a shift mapping.However,other chaotic mappings in symbol space exist too.The basic change is to consider the process not only at a set of times which are equally spaced,say at unit time apart(a shift mapping),but at a set of times which are not equally spaced,say if the unit time can not be fixed.The increasing mapping as a generalization of the shift mapping and the k-switch mapping are introduced.The increasing and k-switch mappings are chaotic. 展开更多
关键词 symbol space Chaotic mapping Increasing mapping k-switch mapping
下载PDF
基于MAPGIS的全国地质工作程度数据库应用系统设计与实现 被引量:7
10
作者 陈志军 陈建国 《物探化探计算技术》 CAS CSCD 2006年第4期381-386,共6页
二十世纪在全国开展了大量地质调查工作,并且建立起“全国地质工作程度空间数据库”,急需研发应用系统保障该数据库作用的充分发挥。这里运用GIS软件工程原理,对应用系统进行了需求分析和系统分析,特别是对各重要模块进行了详细设计。... 二十世纪在全国开展了大量地质调查工作,并且建立起“全国地质工作程度空间数据库”,急需研发应用系统保障该数据库作用的充分发挥。这里运用GIS软件工程原理,对应用系统进行了需求分析和系统分析,特别是对各重要模块进行了详细设计。该应用系统已基于MAPGIS 6.x实现,几项特色功能被重点展示,它们为保障整个系统功能起到了关键性的作用。 展开更多
关键词 地质工作程度数据库 mapGIS 图元叠盖 地图符号化
下载PDF
基于Autodesk Map地图符号库的设计与开发 被引量:2
11
作者 武振枝 谢永智 覃辉 《桂林工学院学报》 CAS 北大核心 2006年第4期525-528,共4页
在地图数字化过程中,经常需要使用一些专门的点、线、面符号来表示特定的地物,而在AutodeskMap的标准符号库中没有这类地图符号.为避免重复繁琐地绘制这些符号实体,在AutodeskMap环境下,依据地图符号的一般特点和编码原则,根据点、线和... 在地图数字化过程中,经常需要使用一些专门的点、线、面符号来表示特定的地物,而在AutodeskMap的标准符号库中没有这类地图符号.为避免重复繁琐地绘制这些符号实体,在AutodeskMap环境下,依据地图符号的一般特点和编码原则,根据点、线和面符号复杂程度和结构形状的不同,采用定制法、PDB开发方法和ObjectARX二次开发方法,设计并创建了特定地物的地图符号库. 展开更多
关键词 AUTODESK map 地图符号库 OBJECT ARX PDB 定制
下载PDF
基于MapInfo的土地利用现状图符号库的设计与实现 被引量:3
12
作者 曹敏 沈泉飞 金丹 《国土资源科技管理》 2006年第3期93-96,共4页
MapInfo系统自带的符号库不能满足我国各种比例尺土地利用现状图的需要,通过分析MapInfo符号的建库原理和方法,同时结合土地利用现状图符号的特点,采用实验的方法解决符号制作的尺寸规律问题,设计、开发了满足国标要求的土地利用现状图... MapInfo系统自带的符号库不能满足我国各种比例尺土地利用现状图的需要,通过分析MapInfo符号的建库原理和方法,同时结合土地利用现状图符号的特点,采用实验的方法解决符号制作的尺寸规律问题,设计、开发了满足国标要求的土地利用现状图符号库,并用实例对符号库的应用做了分析与探讨。 展开更多
关键词 土地利用现状图 符号库 TRUETYPE字体 字体编辑器
下载PDF
基于MapObjects的特殊点符号制作和旋转 被引量:2
13
作者 张成才 马玉荣 +1 位作者 李健 赵东保 《地理空间信息》 2008年第3期4-6,共3页
结合研究项目"河南省内河航道基础地理信息系统",利用Visual Basic和MapObjects开发了航道系统专门的符号库,使用FontCreator字体软件制作所需符号,然后根据点符号旋转算法,利用渲染方法实现了有向点符号不同角度的旋转。
关键词 地理信息系统 mapOBJECTS 地图符号 符号旋转
下载PDF
MapInfo下地图符号库的制作 被引量:5
14
作者 朱春晓 王延亮 刘振坤 《黑龙江工程学院学报》 CAS 2002年第2期20-22,共3页
分析了MapInfo符号制作技术原理,结合地形图点、线、面符号的特点,给出了一组符号制作的具体实例。
关键词 mapINFO 地理信息系统 技术原理 地图符号库 制作
下载PDF
基于ArcMap的地图符号设计与研究 被引量:22
15
作者 薄伟伟 《地理空间信息》 2006年第2期70-72,共3页
地图符号是地图的语言,地图符号的绘制是地理信息系统开发中的一个重要组成部分。主要讨论了ArcMap中地图符号的绘制方法,对几种ArcMap中不能实现的符号简要阐述了绘制方案。
关键词 ARCmap 地图符号 样式经理
下载PDF
基于MapStore软件的图库一体化的生产与实现 被引量:3
16
作者 张新利 高晖 陈新国 《测绘与空间地理信息》 2011年第5期74-76,共3页
MapStore软件是以面向对象的地理空间数据模型作为数据模型基础的,该模型对地理空间数据具有强大的表现力。实体数据、几何数据、符号数据的有机结合,体现了实体3个部分的内容。不同数据的编辑操作在不同的视图环境下进行,既节约了成本... MapStore软件是以面向对象的地理空间数据模型作为数据模型基础的,该模型对地理空间数据具有强大的表现力。实体数据、几何数据、符号数据的有机结合,体现了实体3个部分的内容。不同数据的编辑操作在不同的视图环境下进行,既节约了成本,又实现了数据生产和加工的统一,对制图与建库数据一体化提供了很好的解决方案。 展开更多
关键词 图库一体化 几何视图 实体视图 符号视图
下载PDF
MapObjects中扩展地图注记功能的算法设计与实现
17
作者 张成才 李红伟 +1 位作者 赵东保 张礼 《北京测绘》 2007年第4期12-15,共4页
地图注记是地图制图领域的重要内容,能够增强地图内容的易理解性。不论是普通地图还是专用地图,注记都起着联系制图者和使用者的桥梁和纽带作用。本文结合实际项目"河南省航道基础地理信息系统"的研发研究了利用Visual Basic... 地图注记是地图制图领域的重要内容,能够增强地图内容的易理解性。不论是普通地图还是专用地图,注记都起着联系制图者和使用者的桥梁和纽带作用。本文结合实际项目"河南省航道基础地理信息系统"的研发研究了利用Visual Basic和MapObjects扩展地图注记功能的有关原理、算法和步骤。文字注记主要由MapObjects的注记对象LabelPlacer Object来实现。在地物符号的开发过程中,用Font Creator字体工具设计点符号来实现点状符号的绘制和建库过程,平行线和铁路符号的开发则通过创建类模块分别采用角平分线法和平行线法实现。 展开更多
关键词 地图注记 符号化 地理信息系统
下载PDF
基于VB+MapObjects的点状图片分类渲染的实现
18
作者 鲁宁 杨为民 狄光智 《电脑编程技巧与维护》 2011年第4期80-81,86,共3页
介绍了使用VB+MapObjects实现的点状图片分类渲染方法,为使用MapObjects进行行业地理信息系统开发,直接使用其行标图片进行地图符号可视化表达提供了有效的解决方法和实现途径。
关键词 mapOBJECTS 点状 地图符号
下载PDF
Research on Ubiquitous Map Visualization for Ternary Space
19
作者 Si Wang Guangxia Wang 《Journal of Geoscience and Environment Protection》 2022年第2期162-170,共9页
In the era of information and communication technology (ICT) and big data, the map gradually shows a new qualitative feature of “spatiotemporal ubiquitous” with the extension of its object space, expression space an... In the era of information and communication technology (ICT) and big data, the map gradually shows a new qualitative feature of “spatiotemporal ubiquitous” with the extension of its object space, expression space and information source, which challenges the theory of cartographic visualization. This paper discusses the ubiquitous map visualization from the object content and expression form. Oriented to the ternary space, it divides the object dimension of ubiquitous map visualization and analyzes the expression characteristics of ubiquitous map visualization. Based on that, it constructs the variable system, symbol system and method system of ubiquitous map visualization. With three cases of the metro roadmap, the tag map, and the three-dimensional (3D) city map, the application of the proposed content is explained to illustrate its effectiveness. The research in this paper is expected to further enrich the theoretical basis of cartographic visualization and provide theoretical support for the expression and application of ubiquitous map visualization. 展开更多
关键词 Ubiquitous map Ternary Space Visualization VARIABLES map symbol SCENE
下载PDF
基于符号的MAP算法的Turbo编码调制系统
20
作者 杨鹏 葛建华 《陕西科技大学学报(自然科学版)》 2005年第1期57-60,共4页
将TCM技术和Turbo编码相结合,提出了一种基于8PSK的Turbo TCM系统结构,并可以推广到其它多进制调制方式中,同时提出了相应的译码结构和基于符号的最大后验概率的译码算法。计算仿真表明:其性能不仅比 Turbo码系统更接近 Shannon限,而且... 将TCM技术和Turbo编码相结合,提出了一种基于8PSK的Turbo TCM系统结构,并可以推广到其它多进制调制方式中,同时提出了相应的译码结构和基于符号的最大后验概率的译码算法。计算仿真表明:其性能不仅比 Turbo码系统更接近 Shannon限,而且提高了频带利用率,可以广泛地应用于现代移动通信系统中。 展开更多
关键词 TURBO TCM系统 迭代译码 基于符号的最大后验概率算法
下载PDF
上一页 1 2 37 下一页 到第
使用帮助 返回顶部