共查询到19条相似文献,搜索用时 187 毫秒
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基于3ds Max的虚拟校园三维模型的创建 总被引:3,自引:0,他引:3
研究了基于3ds Max软件的虚拟校园三维模型的创建方法,具体讨论了校区三维建模的流程、建筑三维模型的创建、其它地物模型的创建,利用3ds Max软件建模,创建了东北林业大学校园建筑物三维模型。 相似文献
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围绕房屋建筑原型系统的开发过程,在对虚拟现实技术和计算机几何建模技术进行研究的基础上,设计了房屋建筑的整体结构,并以VRML为开发语言,开发出了具有三维真实感的房屋原型系统,使其具有良好交互性和三维显示效果,克服了HTML单调、交互性差的弱点。 相似文献
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《中南林业科技大学学报(自然科学版)》2019,(12)
随着数字林业和精准林业建设的推进,利用三维可视化技术辅助森林管理的需求越发突出,然而3D森林景观建模与建筑物建模相比具有冠层起伏频繁、形状不规则、光线条件复杂、纹理重复度高、像对间存在非刚体性变化等特点,直接采用普通建模方法构建的三维模型效果不理想。本研究实践了一种无人机倾斜摄影系统与背包式三维激光扫描系统相结合的森林景观三维场景建模方法,讨论了数据获取原理、点云配准方法及数据处理流程,并在潭柘寺森林景区进行实验,验证方法的有效性。结果表明,两种点云配准的整体误差小于2.37 mm,能够满足森林景观三维场景建模的精度要求。该方法不仅能省去倾斜摄影的外业控制点采集过程,还实现了两种技术的优势互补,降低了森林景观三维建模的成本,提高了建模效率,对森林精准计测及精细化管理具有一定实践意义。 相似文献
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应用三维人体CAD模型可在座椅的设计阶段对其舒适性进行灵活、有效地分析。参照二维人体模板拟定三维人体模型的结构划分,以人体形体数据和人机工程学为依托,在SolidWorks造型平台上实现对三维人体模型的建模。通过人体CAD模型对座椅CAD模型的"几何匹配",精确提取坐姿人体模型的姿态角度,对比人体坐姿标准舒适角度范围,实现对座椅舒适性的分析。 相似文献
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中华金叶榆在东北地区的景观应用及其评价 总被引:1,自引:0,他引:1
对东北地区7个中华金叶榆样地进行调查、取样,并采用层次分析法创建中华金叶榆植物景观评价模型。结果表明:东北地区适宜选用中华金叶榆作为景观树,可以丰富树木色彩与形状,中华金叶榆孤植时适宜采用造型形式,群植时配景植物颜色丰富,容易创造出好的景观效果。 相似文献
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统一建模语言UML(Unified Modeling Language)是一种标准的图形化建模语言,它是面向对象分析与设计方法的表现手段,适用于不同的开发环境和软件生命周期。本文主要讨论如何使用UML完成事业单位招考网上报名系统的用例建模、静态建模和动态建模,以提高该系统的文档化、可视化和标准化,并保证系统的可靠性和可用性。 相似文献
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国内外灌木生物量模型研究综述 总被引:4,自引:0,他引:4
灌木林是自然界中广泛存在的一种陆地生态系统类型, 是森林资源的重要组成部分。文中对国内外灌木生物量模型的研究现状进行了综述, 从数据采集、建模方法和模型评价3个方面系统总结了灌木生物量模型研建的技术要点。数据采集主要包括样本单元数的确定、测定因子的选定和样本数据采集3部分, 其中样本数据采集又包括野外鲜质量测定和实验室干质量测定2部分。建模方法的重点是确定灌木生物量模型的结构和选择参数估计方法, 而模型评价的核心是选定合适的评价指标。文中从开展国家级森林植被生物量监测的角度提出建立灌木生物量模型的有关建议, 即首先要确定合理的建模样本单元数, 再选择合适的灌木生物量建模技术方法, 还要重视对所建模型的评价, 给出模型的预估精度指标。 相似文献
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Van Wijk MT Dekker SC Bouten W Bosveld FC Kohsiek W Kramer K Mohren GM 《Tree physiology》2000,20(2):115-122
Modeling stomatal conductance is a key element in predicting tree growth and water use at the stand scale. We compared three commonly used models of stomatal conductance, the Jarvis-Loustau, Ball-Berry and Leuning models, for their suitability for incorporating soil water stress into their formulation, and for their performance in modeling forest ecosystem fluxes. We optimized the parameters of each of the three models with sap flow and soil water content data. The optimized Ball-Berry model showed clear relationships with air temperature and soil water content, whereas the optimized Leuning and Jarvis-Loustau models only showed a relationship with soil water content. We conclude that use of relative humidity instead of vapor pressure deficit, as in the Ball-Berry model, is not suitable for modeling daily gas exchange in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Speulderbos forest near the village of Garderen, The Netherlands. Based on the calculated responses to soil water content, we linked a model of forest growth, FORGRO, with a model of soil water, SWIF, to obtain a forest water-balance model that satisfactorily simulated carbon and water (transpiration) fluxes and soil water contents in the Douglas-fir forest for 1995. 相似文献
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《Forest Ecology and Management》2005,204(1):11-21
Eucalyptus is the most valuable cultivated forest genus in Brazil nowadays. Modeling eucalypts growth has been a challenge for foresters in recent years due to the strong site and genetic variations, management regimes and multiple products generated from those plantations. Because the forest height growth is directly related with the site characteristics and with forest productivity, the improvement on the height growth representation implies in better productivity estimation. A nonlinear mixed-effects model was developed to represent the height growth pattern of eucalypts clonal stands from the Brazilian coastal region. Likewise in other scientific fields, this type of modeling methodology showed to be flexible, precise and accurate, generating multimorphic growth curves for different sites and clones. 相似文献
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Summary Modeling of the kinetic of moisture adsorption by wood has been studied by using cubic samples. The model is based on an explicit numerical method with finite differences. Experiments have been carried out either for determining the data necessary for calculations (diffusivity, amount adsorbed at equilibrium) and for testing the validity of the model. Two different experiments have been done in case of the longitudinal adsorption: the one by increasing the relative humidity of the atmosphere following a discontinuous step by step process. The other by determining the kinetic adsorption of moisture by samples previously equilibrated under the same conditions when they are contacted with atmosphere at various R. H. Good correlations are obtained between calculated values and experiments in both cases. Although the actual paper is concerned with constant diffusivity, the model is capable to use concentration-dependent diffusivities.This work has been done with the help and support of the French C.T.B. (Wood Technical Center), 10 Av. St.-Mandé, Paris 相似文献
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基于UML的企业信息发布系统建模 总被引:1,自引:0,他引:1
近年来建模语言得到广泛应用,已成为系统快速开发的有效工具.本文以企业信息发布系统为例,在对系统功能进行简要介绍的同时,按照UML建模过程对系统进行建模. 相似文献
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异方差对生物量模型构建的影响 总被引:1,自引:0,他引:1
生物量建模中的误差项往往存在异方差性,影响模型的可信度.通过介绍异方差检验和消除的方法,结合兴安落叶松的实测数据,借助SPSS统计软件实现了建模过程中对异方差的检验和消除,并达到了很好的估计效果.结合实例分析,采用模型转换和加权函数的方法对模型的预估效果起到了很好的作用.建立树干的相容性生物量模型,模型决定系数R2为0.947,估计值的标准差SEE为17.368,平均估计误差MPE为2.637,平均相对偏差ME为3.957,平均相对偏差绝对值MAE为0.408,以及预估精度P为92.39%,各项检验指标均符合建模要求. 相似文献