Seabed Classification Using BP Neural Network Based on GA   总被引：4，自引：0，他引：4  

Yang Fanlin  Liu Jingnan 《海洋学报(英文版)》2003,22(4):523-531

INTRODUCTIONUnderwaterremotesensingtools,suchasmulti beam ,sidescansonar,sub bottom pro file ,video ,etc .,arenormalmeanstoexploreseabed .Foreaseofnotation ,sidescansonarim ageisusedtodemonstrateseabedimage .Sidescansonarisakindofhigh resolutionimagingandcancontinuouslymonitorthechangesofseafloor.Inordertorelievetechniciansfromhardhandwork ,theautomaticclassificationbycomputerisneeded .Differentfromthespatialremotesensingimage ,underwatersonarimageistheformernon multi spectralimage .Theo…  相似文献   

基于智能遗传算法和Otsu法的多目标图像分割方法     

Wu Shiying Zheng Zhaobao Yu Xin 《测绘科技情报》2006,(4)

为了克服传统遗传算法在优化多目标图像分割参数时易陷入局部收敛和搜索效率低的缺陷,本文提出一种基于智能遗传算法和Otsu法的多目标图像分割方法,并将它应用于航空影像的分割。实验结果表明,本文提出的算法比传统遗传算法可以更加快速、更稳定地获取图像分割的最优阈值。  相似文献   

Terpene emissions from European beech (shape Fagus sylvatica~L.): Pattern and Emission Behaviour Over two Vegetation Periods     

C. Holzke  T. Dindorf  J. Kesselmeier  U. Kuhn  R. Koppmann 《Journal of Atmospheric Chemistry》2006,55(1):81-102

The source strength of volatile organic compounds (VOCs) emitted by vegetation is of great interest for the understanding of processes in atmospheric chemistry and climate change. In this study terpene emissions from branches of European beech (Fagus sylvatica L.) were studied in a deciduous forest. Using the branch enclosure technique changes in the emission pattern and the variation of emission rates over the year were investigated over two consecutive vegetation periods. More than 10 monoterpene compounds were found in the emissions, among which sabinene dominates. For most compounds the emission pattern changed only slightly over the year. Interestingly, two compounds tentatively identified as para-cymene and cis-ocimene showed differences in the emission behaviour in late summer compared to the other terpenes. In contrast to previous studies our investigation characterise European beech as a strong emitter. For the main compounds the emission rates changed up to two orders of magnitude as a function of temperature and light over the day. In general, highest emission rates were observed in summer and lowest in fall. A seasonality was characterized by a temperature independent decline of emissions in late summer, resulting in changes of the standard emission rate on the order of one magnitude. A standard emission factor of up to 3.5 nmol m⁻²s⁻¹ for the sum of measured terpenes was calculated. No emissions were found in early spring even though leaves were fully developed and temperature and light conditions were moderate. The results underline the importance of characterising the annual variation of the emission behaviour. Especially for the up-scaling to global VOC emissions, seasonal influences have to be considered to achieve realistic emission inventories.  相似文献   

Seasonal dynamics of algal biomass and allochthonous input of coarse particulate organic matter in a low-order sandstone stream (Weidlingbach, Lower Austria)     

Ulrike ArtmannJohann A. Waringer  Michael Schagerl 《Limnologica》2003,33(2):77-91

From December 1997 to December 1998, benthic algal biomass and the input of allochthonous coarse particulate organic matter (CPOM) were investigated in bi-weekly intervals at two sampling stations (shaded and sunny) of the Weidlingbach, a fourth order sandstone stream in the Wienerwald. A total of 41 benthic algal taxa was collected, belonging to the groups Cyanobacteria (4 taxa), Bacillariophyceae (33), Rhodophyta (1), Chrysophyceae (1) and Chlorophyta (2). At the shaded site, periphyton dry mass ranged from 13 g m⁻² in April to 440 g m⁻² in August (annual mean = 93 g m⁻²), at the sunny site from 3 g m⁻² in May to 512 g m⁻² in late fall (annual mean = 70 g m⁻²). Based on the algal carotenoid pattern, Bacillariophyceae were most abundant in fall and winter while Chlorophyceae dominated during summer. Mean annual standing stock of chlorophyll-a was 8.65 μg cm⁻² at the shaded station and 7.53 μg cm⁻² at the sunny site. Annual allochthonous CPOM input rates ranged from 382 to 665 g dry mass m⁻² for aerial input and from 1006 to 1062 g DM m⁻¹ of stream length for lateral input. Lateral input rates were influenced by the bank inclination; the temporal distribution of aerial input showed an autumnal maximum (61-65% of the total). Direct CPOM input was significantly highest (P<0.05) during the period of defoliation from October to November. In the course of this period, 61.1% (shaded) to 64.9% (sunny) of the annual CPOM dropped into the brook, yielding daily input rates of 6.6 to 4.0 g DM m⁻². From December to September, daily direct input rates decreased to 0.84 g DM m⁻² (shaded) and 0.44 g DM m⁻² (sunny). At both sites, retention capacity was high; 70% of marked leaves released along transects were retained by coarse sediment particles within 40 m from the starting point. The annual mean of periphyton dry mass made up 52% of CPOM standing stock at the shaded site and 39% at the sunny site.  相似文献   

一种基于似三棱柱体元的地质三维建模方法研究   总被引：4，自引：0，他引：4  

程朋根刘学斌  史文中王伟 《华东地质学院学报》2004,27(1):73-79

三堆空间建模方法是三堆地劫工程GIS研究的核心问题之一。提出一种基于似三棱柱体元的三堆数据模型，模型包含顶点、线段(棱边、三角形边)、三角形、侧面四边形、三棱柱体元5个基本元素。和点对象、线对象、面对象、体对象、复杂对象、空间对象等6个对象。设计了5个基本元素和3种地质对象的数据结构和它们之间的拓扑关系。以岩体和巷道为例。给出了似三棱柱体建模思路和算法。利用内蒙古某矿区实际钻孔资料和模拟巷道数据对所开发的系统原型进行验证。研究表明。基于似三棱柱体元的数据模型的优势在于可以表示空间对象的表面和内部结构。便于建模和节省存储空间，同时便于不规劓的自然地质体和规则勘探工程建模。  相似文献   

Multiobjective optimal FLC driven hybrid mass damper system for torsionally coupled,seismically excited structures     

A. S. Ahlawat  A. Ramaswamy 《地震工程与结构动力学》2002,31(12):2121-2139

In most of the research work on structural vibration control only two‐dimensional plane structural modelling has been considered, although only a few practical building structures can be modelled as planar structures. Therefore, these methods are not directly applicable to the majority of the practical building structures. This paper discusses the design of a multiobjective optimal fuzzy logic controller (FLC) driven hybrid mass damper (HMD) system for seismically excited torsionally coupled building structures. Floor acceleration and velocity information have been used as feedback to the fuzzy logic controller. A three branch tournament Genetic Algorithm has been used for the multiobjective optimal design of the FLC driven HMD system, where the minimization of the non‐dimensionalized peak displacement, acceleration and rotation of the structure about its vertical axis, have been as the three objective functions. The proposed multiobjective optimal fuzzy logic controller has been verified for an example problem reported in the literature. This HMD system consists of four HMDs arranged in such a way that the system can control the torsional mode of vibration effectively in addition to the flexure modes of vibration. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Research　on　TSIP　method　for　medium－term　earthquake　prediction     

黄德瑜  朱元清  陈颙  季颖 《地震学报(英文版)》1995,8(4):501-510

ＲｅｓｅａｒｃｈｏｎＴＳＩＰｍｅｔｈｏｄｆｏｒｍｅｄｉｕｍ－ｔｅｒｍｅａｒｔｈｑｕａｋｅｐｒｅｄｉｃｔｉｏｎＤｅ－ＹｕＨＵＡＮＧ（黄德瑜）；Ｙｕａｎ－ＱｉｎｇＺＨＵ（朱元清）；ＹｏｎｇＣＨＥＮ（陈颙）ａｎｄＹｉｎｇＪＩ（季颖）（ＣｅｎｔｒｅｆｏｒＡｎ...  相似文献   

GRIDVRGM：快速计算规则测网数据的实验半变异函数的FORTRAN77程序     

陈明 《吉林地质》1995,(3)

本文介绍了一个在规则测网时快速计算实验半变异函数的ＦＯＲＴＲＡＮ７７程序。其目的是使广大用户在进行克里格估值之前，快速获得实验半变异函数，且不影响计算精度。  相似文献   

2DRE四叉树的集合运算算法     

萧柯 《遥感学报》1992,(4)

本文提出并分析了一系列四叉树的集合运算算法。通过引入集合论,将时空复杂度较高的图像转换为简单的算术运算来进行,从而使问题的解决大大简化。文中介绍了算法的基础,详细阐述了诸算法,并对其进行了评价和分析,进而引伸到数据结构及算法的研究在应用领域中的作用和意义。  相似文献   

现行弧长算法的几何探义   总被引：1，自引：0，他引：1  

王本善  王楠 《测绘学报》1993,22(3):205-211

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