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计算机在公路测设特殊线形中的应用 被引量:1
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作者 张君 郭强 +2 位作者 西玉清 于春 杨学广 《黑龙江交通科技》 2003年第9期49-49,51,共2页
在公路测设中 ,经常遇到各种复杂的不利条件 ,使测设难度增大。本文提出采用贝筛尔曲线 ,利用计算机语言编制程序可解决各种特殊情况下的公路线形测设 ,使线形达到圆滑平顺 ,满足规范和实际要求。
关键词 公路测设 贝筛尔曲线 计算机语言编制程序 特殊线形 曲线拼接
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Geospacial information utilized under the access control strategy
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作者 田捷 《Journal of Chongqing University》 CAS 2007年第4期256-264,共9页
This paper introduces a solution to the secure requirement for digital rights management (DRM) by the way of geospacial access control named geospacial access control (GeoAC) in geospacial field. The issues of aut... This paper introduces a solution to the secure requirement for digital rights management (DRM) by the way of geospacial access control named geospacial access control (GeoAC) in geospacial field. The issues of authorization for geospacial DRM are concentrated on. To geospacial DRM, one aspect is the declaration and enforcement of access rights, based on geographic aspects. To the approbation of digital geographic content, it is important to adopt online access to geodata through a special data infrastructure (SDI). This results in the interoperability requirements on three different levels: data model level, service level and access control level. The interaction between the data model and service level can be obtained by criterions of the open geospacial consortium (OGC), and the interaction of the access control level may be reached by declaring and enforcing access restrictions in GeoAC. Then an archetype enforcement based on GeoAC is elucidated. As one aspect of performing usage rights, the execution of access restrictions as an extension to a regular SDI is illuminated. 展开更多
关键词 spacial technologies geospacial services access control rights expression languages
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