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城市地下管线三维建模工具开发及应用 被引量:7
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作者 张鹏程 丘广新 +1 位作者 陈鹏 张秀英 《地理空间信息》 2016年第7期85-87,共3页
首先对常用的管线三维建模方法进行了归纳总结;在分析不同方法的应用范围、综合考虑各种建模方法优缺点的基础上,基于Direct X9.0、.NET Framework3.5运行环境,采用C++语言,集成开发了管线三维建模工具。以广州市现有二维管线数据库为例... 首先对常用的管线三维建模方法进行了归纳总结;在分析不同方法的应用范围、综合考虑各种建模方法优缺点的基础上,基于Direct X9.0、.NET Framework3.5运行环境,采用C++语言,集成开发了管线三维建模工具。以广州市现有二维管线数据库为例,该工具通过对编码、字段、材质、特征、附属物等信息的映射设置,能快速、高效地实现管线的三维建模。 展开更多
关键词 地下管线 三维建模工具 自动化建模 映射设置
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A novel mapping scheme and modified decoding algorithm for BICM-ID
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作者 方伟伟 Li Jianping Cai Chaoshi 《High Technology Letters》 EI CAS 2013年第1期70-75,共6页
This paper proposes a novel mapping scheme for bit-interleaved coded modulation with iterative decoding(BICM-ID).The symbol mapping is composed of two QPSK with different radiuses and phases,called cross equalization-... This paper proposes a novel mapping scheme for bit-interleaved coded modulation with iterative decoding(BICM-ID).The symbol mapping is composed of two QPSK with different radiuses and phases,called cross equalization-8PSK-quasi-semi set partitioning(CE-8PSK-Quasi-SSP).Providing the same average power,the proposed scheme can increase the minimum squared Euclidean distance(MSED)and then improve the receiving performance of BICM-ID compared with conventional symbol mapping schemes.Simultaneously,a modified iteration decoding algorithm is proposed in this paper.In the process of iteration decoding,different proportion of the extrinsic information to the systematic observations results in distinct decoding performance.At high SNR(4~9dB),the observation information plays a more important role than the extrinsic information.Simulation results show that the proportion set at 1.2 is more suitable for the novel mapping in BICM-ID.When the BER is 10^(-4),more than 0.9dB coding gain over Rayleigh channels can be achieved for the improved mapping and decoding scheme. 展开更多
关键词 bit-interleaved coded modulation with iterative decoding (BICM-ID) minimum squared Euclidean distance (MSED) average power tioning CE-8PSK-Quasi-SSP) extrinsic information cross equalization-8PSK-quasi-semi set parti- priori information weighted coefficient
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