共查询到20条相似文献,搜索用时 625 毫秒
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研究了工程图学课程中虚拟测绘模型的设计.根据模型测绘教学的特点,确定了虚拟测绘模型的功能;设计了虚拟模型测绘流程;构建了模型测绘系统的结构.通过分析VRML节点的特性解决了系统的观察问题和模型点的选择提示及坐标的获得问题.设计了易于操作和理解的交互界面,实现了虚拟测绘模型系统. 相似文献
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基于VRML-Java平台的工程图学网络实验系统研究与实现 总被引:2,自引:0,他引:2
对工程图学网络实验系统的设计进行了研究。针对工程图学实验的特点及对实验系统的要求,确定了实验系统基于VRML-Java的构建平台;深入分析探讨了系统中的实验立体构建方法,通过分析VRML场景中形体构造的原理,设计了实验系统的模型数据结构和模型实时变形时数据修改的算法;系统设计了具有较强交互性的操作界面,实现了一个基于Internet的工程图学实验系统。 相似文献
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针对工程图学虚拟实验的特点,确定了系统控制虚拟模型时的三个需求:获得模型的状态数据、读取模型的几何结构数据、程序动态生成模型。论文研究了Java程序控制VRML的方法,获取VRML模型数据的方法,生成虚拟模型的方法等几个实现模型控制中的关键技术。实验验证,这些关键技术满足系统控制虚拟模型的需求,为解决虚拟实验系统开发中的几个难点问题提供了新手段,也为其他VRML虚拟系统开发提供了有用技术支撑。 相似文献
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目的 目前基于移动设备背面屏输入技术的相关研究,大多集中于其在物理键盘布局或是体型较大的移动设备(如iPad)上的探究,而基于小型移动设备(如手机)的背面屏盲打输入法键盘布局的相关研究并不多见.手机背面虚拟键盘的使用可极大程度释放前屏空间,实现前屏交互任务与背屏文本输入的同步进行.基于此研究意义,探讨智能手机背面屏盲打输入法的可行性及设计方案.方法 通过用户访谈和文本输入测试,采集并分析24167条用户输入数据.结果 智能手机背面屏的横向QWERTY键盘布局为左右拆分式,整体位于双手手持时偏上部的位置.结论 通过对用户在智能手机背面屏盲打输入偏好的研究,可以得出一个具有较强一致性的横向QWERTY键盘布局,为未来背面屏盲打输入法键盘布局设计提供指导. 相似文献
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基于Web的虚拟现实模型创建工具 总被引:9,自引:3,他引:9
虚拟现实模型语言VRML(Virtual Reality Modeling Language)可用于构造基于Web的三维虚拟场景,但由于其自身的繁杂性,直接构造三维虚拟空间较为困难。针对这种情况,提出了一种基于Web的虚拟现实模型创建工具的实现方法,用Visual C 6.0 作为系统开发平台,用目前通用的3D图形API标准OpenGL 实现模型预览。采用面向对象技术,达到了无须直接接触VRML代码进行编码生成可供Web浏览的三维模型的目的,从而可提高VRML构造虚拟场景的工作效率。 相似文献
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A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling. 相似文献
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Liebert A Wabnitz H Grosenick D Möller M Macdonald R Rinneberg H 《Applied optics》2003,42(28):5785-5792
A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue. 相似文献
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An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a
rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate
agreement is demonstrated between the derived relations and experimental data. 相似文献
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Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995. 相似文献
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由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。 相似文献
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M. M. Gadenin 《Inorganic Materials》2013,49(15):1352-1356
It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle. 相似文献
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V. T. Kornienko 《Strength of Materials》1991,23(7):760-765
The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991. 相似文献
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水三相点是开尔文热力学温度的唯一基准点,也是ITS-90国际温标重要的定义固定点。因此,水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来,中国计量科学研究院研制出一系列高质量的水三相点容器,加强了水三相点的研究,为不确定度的分析提供了更为可靠的实验依据。同时,不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此,根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明,其扩展不确定度为0.16mK(k=2.69,P=0.99)。 相似文献