基于多波段影像特征的土地利用分类

利用Landsat TM遥感影像,在ENVI4.2软件的支持下,分析了甘肃省张掖市TM多波段地物影像特征,建立解译标志,利用监督分类方法对该区域土地利用进行分类。     

TM遥感影像的最佳波段研究——以甘肃敦煌阳关国家级自然保护区为例

选择甘肃敦煌阳关国家级自然保护区TM遥感影像为试验数据,采用最佳指数因子方法(OIF)并结合试验区地物光谱特征进行TM影像最佳波段选取的研究。结果表明:TM125波段组合为甘肃敦煌阳关国家级自然保护区TM影像的最佳波段组合,三个波段包含了较大的数据量,波段与波段之间的相关性较小,其合成的彩色影像易于目视解译,为保护区开展工作奠定了基础。     

基于RS和GIS集成技术的大连湿地资源调查

利用RS和GIS集成技术,对大连地区Landsat卫星遥感影像进行解译.根据《湿地公约》中湿地的规定并结合大连实际情况,将大连湿地资源分为两级(天然和人工湿地)6大类:河流、库塘、海岸湿地、海洋湿地、水稻田、沼泽、养殖场及盐场.采用TM5、TM4、TM3波段合成图像并进行影像解译,建立解译标志物并进行野外考察校正,得出大连湿地的面积及其分布状况.最后对大连湿地资源的可持续发展提出建议.     

广西横县土地利用现状遥感调查

在1990年土地详查基础上，以1：5万TM影像为研究的基本信息源，应用遥感解译原理与方法，通过确定上地利用现状分类系统、建立解译标志、进行编图和面积量算及结果分析等工作，对横县上地资源利用现状进行了调查与调整；并就上地利用中存在的问题提出了应采取的对策。     

基于遥感技术的内蒙古自然旅游资源开发研究

采用遥感技术与典型地区地面调查相结合的方法，对内蒙古的自然旅游资源进行调查，通过各种自然旅游资源的光谱特征与TM影像色彩的对应关系以及选取的典型地区调查等建立了准确的解译标志，并以TM741波段合成的真彩色遥感影像图为主要资料进行目视解译，从而判读出主要自然旅游资源，并发现了新的旅游资源．     

TM遥感影像彩色合成最佳波段组合研究——以恩施市土地利用遥感图制作为例

TM遥感数据具有适合于中等尺度研究的空间分辨率,并相对易于获取,在土地变化研究中应用最为普遍.TM遥感数据为多光谱数据,最佳波段选取是遥感图像增强处理的关键部分,直接影响到目视解译和研究对象的信息提取.采用OIF指数法确定恩施市2000年TM遥感数据的最佳波段组合,完成土地利用遥感图制作.研究结果表明,OIF指数法易于操作,确定最佳波段组合效果较好.     

基于ETM+遥感影像的森林植被信息提取方法研究

以南京市区的遥感影像图为研究对象,对基于ETM 遥感影像的森林覆盖面积提取的一般方法进行研究.笔者分析了ETM 影像波段的特征值和相关性,得出TM3、TM4、TM5之间的相关性小,包含信息量丰富;采用Brovey变换将TM3、TM4、TM5与PAN波段融合,并提出用融合后的波段TM4R和TM3R作归一化植被指数,得到NDVIR;然后利用最大似然法对融合图像和NDVIR的组合图像进行分类,根据分类结果计算出南京市森林覆盖率为38.63%.     

基于遥感和GIS的都安瑶族自治县土地利用/覆被变化分析

该文以都安瑶族自治县为研究对象,利用 1988年和 1999年都安县卫星遥感数据( Landsat/TM)和有关资料,依托遥感和 GIS技术,确定地物类型、建立解译标志、分析遥感图像处理方法和遥感解译过程,进而对都安土地利用 /覆被变化进行分析.     

遥感技术在张北坝上草地资源调查中的应用

以试区1986经相嵌纠正的1/5万正射投影航片为基本遥感信息源,结合1984年试区TM2、3、4波段假彩色合成卫片,采用目视判读解译方法。综合分析与逻辑推理相结合,建立判读解译标志,编制解译检索表,完成试区土地利用与草地资源调查与制图,定性、定位、定量准确。遥感技术用于坝上土地及草地调查制图,具有速度快、省工时、成本低、精度高的效果。     

利用TM影像提取土地利用/覆被信息的最佳波段研究

以土地利用/土地覆被信息的提取为目的,选定武汉市江夏区的TM遥感影像为试验数据,在对其信息特征进行统计与分析的基础上,通过采用最佳指数因子(OJF)并综合试验区地物光谱特征的分析方法进行TM 影像最佳波段选取的研究.结果表明:TM543波段组合为土地利用/覆被遥感中TM 影像的最佳波段组合,其合成的假彩色影像具有很好的...     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。