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《电子科技文摘》 2000年第9期64-66,共3页
大城市双向 CATV 网交互业务的实现[刊]/欧阳捷//广播与电视技术.—2000,27(3).—129~135(B)提出了在大城市双向 CATV 网上实现交互业务的分级系统结构,包括小区中心站的组成模块、功能以及双向机顶盒的结构。提出了大型 CATV 网上实现... 大城市双向 CATV 网交互业务的实现[刊]/欧阳捷//广播与电视技术.—2000,27(3).—129~135(B)提出了在大城市双向 CATV 网上实现交互业务的分级系统结构,包括小区中心站的组成模块、功能以及双向机顶盒的结构。提出了大型 CATV 网上实现VOD 的实用方案,通过多种 VOD 方式(TVOD、NVOD、INVOD、ANVOD)动态组合实现高质量的VOD 业务。探讨了交互业务如何在系统各级上合理分配。 展开更多
关键词 电视技术 交互业务 分级系统结构 广播电视 双向机顶盒 高质量 大城市 有线电视网 实用方案 视频点播系统
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Evolutionary model of the central place hierarchical system 被引量:1
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作者 LU YuQi YUAN LinWang ZHONG YeXi 《Science China Earth Sciences》 SCIE EI CAS 2011年第10期1614-1626,共13页
Central place theory is one of the two theoretical cornerstones of geography, yet it cannot be connected with other spatial structure models, fails to provide definite time-space parameter conditions, lacks an evoluti... Central place theory is one of the two theoretical cornerstones of geography, yet it cannot be connected with other spatial structure models, fails to provide definite time-space parameter conditions, lacks an evolutionary process model, and does not easily enable construction of a complete theoretical system of regional spatial structure. This paper gives an in-depth analysis of the process and mechanism for production and evolution of central places of different grades, and constructs an evolutionary model of the central place hierarchical system. The results of deduction, analysis and simulation show that production and evolution of the central place hierarchical system may be divided into five stages. These stages are the embryonic, formative, improvement, maturation, and advancement stages. Affected by spatial location and centricity, central places have obvious differences in scale and functional structures. There are great differences in the scale of same-grade central places. However, low-grade central places could have larger scales than high-grade central places, and the central places of a central location may form the agglomeration area of central places. Based on the hypothesis condition of an isotropic plain, the research shows that it is possible not only to form proportional functional structures of central places, but also to produce non-proportional scale structures of central places, and thus to complete the transformation from rationalistic deduction of spatial equilibrium mode to an explanation and demonstration of an unbalanced practical model. 展开更多
关键词 central place theory hierarchical system evolutionary model functional structure scale structure
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