Approximation of NURBS Curves and Surfaces Using Adaptive Equidistant Parameterlzatlons

Non-uniform rational B-spline (NURBS) curves and surfaces are very important tools for modelling curves and surfaces. Several important details, such as the choice of the sample points, of the parameterization, and of the termination condition, are however not well described. These details have a great influence on the performance of the approximation algorithm, both in terms of quality as well as time and space usage. This paper described how to sample points, examining two standard parameterizations: equidistant and chordal. A new and local parameterization, namely an adaptive equidistant model, was proposed, which enhances the equidistant model, Localization can also be used to enhance the chordal parameterizatfon, For NURBS surfaces, one must choose which direction will be approximated first and must pay special attention to surfaces of degree 1 which have to be handled as a special case.     

基于Flash的工程制图CAI课件的研究与开发

随着Flash作品在网络上的广泛传播，其强大的动画功能吸引了越来越多的教师开始利用Flash来制作多媒体CAI课件．本文分析了工程制图传统教学中存在的问题和不足，介绍了用Flash MX 2004来开发工程制图多媒体教学系统CAI课件的基本思想、系统设计、开发流程、素材的准备、动画的制作、实现手段及其特点．在教学实践中应用该软件取得了较好的效果．     

关于贯彻新国标及图样简化工作的几点思考

图样简化是工程图学的重要内容之一,也是工程语言发展的必然规律.宣传贯彻制图新国标及图样简化工作势在必行.制图标准与图样简化的关系,制图教学中贯彻新标准的重要性,企业院所中大力开展图样简化都十分重要,这些工作将会取得很大的经济效益和社会效益.     

旅游规划图制图规范研究

探讨了旅游规划图的性质,指出在我国旅游规划中由于编制单位的专业背景不同使得旅游规划图的制作各不相同,表现在有些规划图失去地图的基本属性、没有统一的图式图例和图集选题的差异;文中认为旅游规划图的规范化应从三个方面进行,即确保旅游规划图具备地图基本属性,编制统一的旅游规划图图式及统一旅游规划图的内容体系.最后对旅游规划电子地图的规范化进行探讨.     

工程制图电子挂图的研制

随着教学改革的不断深入，给工程制图的传统教学手段和教学模式带来了巨大冲击，使木模、挂图等传统的教具难以发挥作用。本文介绍了利用计算机技术研制工程制图电子挂图的过程及应用促进了教学手段的现代化。     

水工制图MCAI课件的设计与实现

对水利工程制图MCAI课件的制作目的、课件的系统结构设计、个性化设计、制作技术等问题进行了阐述。讨论了如何处理好课件制作过程中几种相关工具软件间相互调用、转换问题。并以课件“组合体”部分的制作为实例，对水工制图MCAI课件开发的基本模式和基本结构进行分析，就如何表述由平面图形想像物体的空间形状这一思维过程及相关动画的制作手段进行了探讨。     

高师开设“化工制图”选修课的探讨

高师开设《化工制图》课有利于培养学生的绘图 ,读图和图解能力以及耐心细致的工作作风。因此很有必要对本课程教材、教学内容的选择以及如何搞好这门课的教学进行探索。     

《西安市地图集》总体设计思想

从《西安市地图集》的总体设计思想方面,研究其编制目的、特点、性质、数学基础、开本、形式、内容结构、编排原则、地理底图和编制工艺等问题,为城市制图提供技术实践和理论基础。     

搪瓷陶瓷产品造型设计图形显示系统

介绍了系统的主要功能及设计方法,本系统提供了真实感图形的显示,图形逼真、自然,在处理真实感图形中,采用了较合适的花纹映射和光源球面缓冲器法处理阴影,使图形生成的逼真性和实时性得到了较好的统一。     

Genetic and physical finemapping of the Sc locus conferring indica-japonica hybrid sterility in rice （Oryza sativa L.）

Hybrid sterility is a major hindrance to utilizing the heterosis in indica-japonica hybrids. To isolate a gene Sc conferring the hybrid sterility, the locus was mapped using molecular markers and an F2 population derived from a cross between near isogenic lines. A primary linkage analysis showed that Sc was linked closely with 4 markers on chromosome 3, on which the genetic distance between a marker RG227 and Sc was 0.07 cM. Chromosome walking with a rice TAC genomic library was carried out using RG227 as a starting probe, and a contig of ca. 320 kb covering the Sc locus was constructed. Two TAC clones, M45EI4 and M90J01 that might cover the Sc locus, were partially sequenced. By searching the rice sequence databases with sequences of the TACs and RG227 a japonica rice BAC sequence, OSJNBb0078P24 was identified. By comparing the TAC and BAC sequences, six new PCR-based markers were developed. With these markers the Sc locus was further mapped to a region of 46 kb. The results suggest that the BAC OSJNBb0078P24 and TAC M45EI4 contain the Sc gene. Six ORFs were predicted in the focused 46-kb region.