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终端区进场流的路径选择研究 被引量:3
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作者 高伟 叶志坚 陈晨 《交通信息与安全》 2016年第4期29-36,共8页
在实际运行中,通常依据管制员的经验对进场航班流的路径进行管理,缺乏科学性。针对终端区进场流的路径选择与进场排序的流量管理问题,以进场航班的总完成时间最短为目标,建立基于时间窗与位置约束的路径选择与排序的数学模型。采用先选... 在实际运行中,通常依据管制员的经验对进场航班流的路径进行管理,缺乏科学性。针对终端区进场流的路径选择与进场排序的流量管理问题,以进场航班的总完成时间最短为目标,建立基于时间窗与位置约束的路径选择与排序的数学模型。采用先选择路径再排序的循环寻优的方法进行求解,将禁忌搜索(TS)与排序算法相结合,设计了TS-FCFS与TS-DP两种算法,着重建立了基于关键路径的邻域结构,并加入有效的重置(RESTAR)策略,使算法快速有效的收敛至最优解。最后借助SIMMOD仿真平台验证算法的可行性。以北京首都机场21架航班为例,仿真结果显示,TS-FCFS与TS-DP两种方法较原计划的进场路径总完成时间分别节约了149s与175s。该路径选择算法降低了进场时间,提高了终端区进场效率。通过合理优化进场航班流的路径选择与进场排序,平衡了跑道负荷,减少了航空器间潜在的冲突,同时为管制员调配进场航班流提供了合理有效的路径选择建议。 展开更多
关键词 航空管理 进场航班 路径选择 进场排序 禁忌搜索 动态规划
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近代汉语中“与”“给”字式使役句研究
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作者 刘海波 《贵州大学学报(社会科学版)》 2015年第4期174-180,共7页
近代汉语使役句的句法结构可以表述为"主语+使役动词+兼语+VP",语义结构可以表述为"致事+使役标记+被使者+结果"。通过对近代汉语"与"和"给"字式使役句句法和语义结构的分析,我们可以更加清楚... 近代汉语使役句的句法结构可以表述为"主语+使役动词+兼语+VP",语义结构可以表述为"致事+使役标记+被使者+结果"。通过对近代汉语"与"和"给"字式使役句句法和语义结构的分析,我们可以更加清楚地勾勒其发展变化过程,即使役动词从动作义到具体使役,再到抽象使役或被动义。 展开更多
关键词 使役 被动
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Identification of Key Ecosystem Services That Can Be Delivered by Water or Wind from Zhangjiakou-Chengde Region to Beijing 被引量:1
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作者 LI Qingxu ZHANG Biao +1 位作者 XIE Gaodi WANG Shuang 《Journal of Resources and Ecology》 CSCD 2018年第6期632-641,共10页
Rapid urbanization causing serious air pollution and ecological risks in the Beijing–Tianjin–Hebei region in North China has attracted worldwide attention. This study estimates the key ecosystem services of land cov... Rapid urbanization causing serious air pollution and ecological risks in the Beijing–Tianjin–Hebei region in North China has attracted worldwide attention. This study estimates the key ecosystem services of land covers in Zhangjiakou and Chengde, and analyzes their main contributions and the effects of ecosystem service flows to Beijing. Results indicated that the total economic value of key ecosystem services in the Zhangjiakou–Chengde region was CNY 189.5 billion in 2013, and that these services were generated mainly from the forestlands, grasslands, and farmlands of Chengde and the eastern region of Zhangjiakou. However, nearly half of land covers provided low ecosystem service values and thus should be enhanced. In addition, approximately 21% of key ecosystem services were delivered from the Zhangjiakou–Chengde region into Beijing, and the flow feasibilities of ecosystem services delivered by water and wind reached 34% and 12%, respectively. Chicheng, Zhuolu, Chongli, Huailai, Xuanhua and Guyuan counties contributed 61% of the ecosystem services flowing into Beijing, and each service showed high regional relationships with Beijing(flow index ≥ 40%). Thus, these services should be prioritized in terms of ecological compensation funds and policies from Beijing. 展开更多
关键词 key ecosystem service supply and flow land cover Beijing-Tianjin-Hebei region Zhangjiakou-Chengde region
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