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拔牙矫治前后的牙模型测量研究 被引量:10
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作者 王红梅 刘郁 《北京口腔医学》 CAS 1999年第3期122-126,共5页
目的:通过模型测量了解拔除4|44|4的病例矫治后上下颌牙弓长度、宽度,牙槽骨宽度及基骨的长度、宽度的改变。方法:选取32例拔除4|44|4患者矫治前后的记存模型进行测量,用SYSTAT统计软件进行数据处理。结果:矫... 目的:通过模型测量了解拔除4|44|4的病例矫治后上下颌牙弓长度、宽度,牙槽骨宽度及基骨的长度、宽度的改变。方法:选取32例拔除4|44|4患者矫治前后的记存模型进行测量,用SYSTAT统计软件进行数据处理。结果:矫治后上下颌牙弓长度、宽度,牙槽骨宽度,上颌基骨前部宽度,下颌基骨宽度均比矫治前减小,统计结果有显著性差异,上颌基骨长度和后部宽度无显著性改变。结论:采用拔除4|44|4的矫治方法可引起上下颌牙弓长度、宽度及牙槽骨宽度的改变,上颌基骨的长度及后部宽度变化不大,而其基骨前部宽度的改变和下颌基骨的模型测量方法还有待进一步探讨。 展开更多
关键词 拔牙矫治 牙弓 牙槽 基骨测量 口腔正畸
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Road Density Analysis Based on Skeleton Partitioning for Road Generalization 被引量:2
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作者 艾廷华 刘耀林 《Geo-Spatial Information Science》 2009年第2期110-116,共7页
This paper proposes an algorithm for road density analysis based on skeleton partitioning. Road density provides metric and statistical information about overall road distribution at the macro level. Existing measurem... This paper proposes an algorithm for road density analysis based on skeleton partitioning. Road density provides metric and statistical information about overall road distribution at the macro level. Existing measurements of road density based on grid method, fractal geometry and mesh density are reviewed, and a new method for computing road density based on skeleton partitioning is proposed. Experiments illustrate that road density based on skeleton partitioning may reveal the overall road distribution. The proposed measurement is further tested against road maps at 1:10k scale and their generalized version at 1:50k scale. By comparing the deletion percentage within different density interval, a road density threshold can be found, which indicate the need for further operations during generalization. Proposed road density may be used to examine the quality of road generalization, to explore the variation of road network through temporal and spatial changes, and it also has future usage in urban planning, transportation and estates evaluation practice. 展开更多
关键词 multiple-representation map generalization road density skeleton partitioning
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