Integrating land use type and other geographic information within spatial interpolation has been proposed as a solution to improve the performance and accuracy of soil nutrient mapping at the regional scale. This stud...Integrating land use type and other geographic information within spatial interpolation has been proposed as a solution to improve the performance and accuracy of soil nutrient mapping at the regional scale. This study developed a non-algorithm approach, i.e., applying inverse distance weighting （IDW） and ordinary kriging （OK）, to individual land use types rather than to the whole watershed, to determine if this improved the performance in mapping soil total C （TC）, total N （TN）, and total P （TP） in a 200-km2 urbanizing watershed in Southeast China. Four land use types were identified by visual interpretation as forest land, agricultural land, green land, and urban land. One hundred and fifty soil samples （0-10 cm） were taken according to land use type and patch size. Results showed that the non-algorithm approach, interpolation based on individual land use types, substantially improved the performance of IDW and OK for mapping TC, TN, and TP in the watershed. Root mean square errors were reduced by 3.9% for TC, 10.770 for TN, and 25.9% for TP by the application of IDW, while the improvements by OK were slightly lower as 0.9% for TC, 7.7% for TN, and 18.1% for TP. Interpolations based on individual land use types visually improved depiction of spatial patterns for TC, TN, and TP in the watershed relative to interpolations by the whole watershed. Substantial improvements might be expected with denser sampling points. We suggest that this non-algorithm approach might provide an alternative to algorithm-based approaches to depict watershed-scale nutrient patterns.展开更多
在工业化建造和碳减排的背景下,预制装配化得到了极大关注。以装配式铁路桥梁为对象,首先,考虑4种典型构件类型(箱梁、桥面板、桥墩和盖梁),核算其预制与现浇两种方式在物化阶段的立方单项碳排放和建造成本,并构建以构件预制率为决策变...在工业化建造和碳减排的背景下,预制装配化得到了极大关注。以装配式铁路桥梁为对象,首先,考虑4种典型构件类型(箱梁、桥面板、桥墩和盖梁),核算其预制与现浇两种方式在物化阶段的立方单项碳排放和建造成本,并构建以构件预制率为决策变量的碳排放-成本双目标优化模型,系统优化预制构件的选择与组合;其次,采用非支配排序的鲸鱼优化算法(Non-Dominated Sorting Whale Optimization Algorithm,NSWOA)对构件组合方案进行求解,获得Pareto均衡解集;再次,通过博弈论思想融合主客观权重,并采用优劣解距离法(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)对Pareto均衡解集进行科学决策,得到最佳构件组合方案;最后,以某西部装配式铁路桥梁为例开展实证分析。结果显示:优化方案较初始方案碳排放减少了361.66 t,成本减少了213.06万元。此外,预制率情景分析显示,不同的桥梁预制率对应不同的最佳构件组合,且碳排放与成本随预制率变化呈现不同趋势。研究成果可为装配式铁路桥梁低碳施工提供有效的优化策略。展开更多
针对超导电机多层绝热(multi-layer insulation,MLI)材料低热流密度需求与紧凑型整机要求的设计矛盾,提出一种基于改进逐层(layer by layer,LBL)模型与二代非支配排序遗传算法的多层绝热多目标协同优化方法。首先,基于辐射传热、气体导...针对超导电机多层绝热(multi-layer insulation,MLI)材料低热流密度需求与紧凑型整机要求的设计矛盾,提出一种基于改进逐层(layer by layer,LBL)模型与二代非支配排序遗传算法的多层绝热多目标协同优化方法。首先,基于辐射传热、气体导热与固体导热方程,通过引入间隔层光学性质、反射屏开孔率及动态自适应系数等关键参数,提升常规LBL模型的计算精度。其次,结合各项传热占比特点,构建最大为四密度区的变密度MLI模型。然后,采用非支配排序遗传算法,以各密度区层数为优化变量,以改进LBL模型作为算法适应度计算函数,约束各密度区层数以及各密度区层数之和,经种群进化得到Pareto前沿。在此基础上,进一步分析了绝热材料热流密度与密度区数量、各密度区层数、层密度的关系以及变密度敷设对热流分布的调控能力。研究结果表明,优化方案中热流密度覆盖0.42~3.11 W/m^(2)、厚度覆盖5.5~43.0 mm,敷设方式覆盖不同层密度的定密度方案、两密度区变密度、三密度区变密度以及四密度区变密度方案。通过调控密度区数量以及密度区的层数、层密度可以实现多层绝热材料优化,降低后续施工难度。展开更多
外辐射源雷达利用直达天线接收的参考信号作为样本滤除目标回波中的杂波,但由于雨、云、树木或其他运动物体等的影响,回波内可能会包含非零频杂波,导致处理后杂波残余较大,影响目标检测。针对上述问题,提出了一种基于杂波识别的扩展最...外辐射源雷达利用直达天线接收的参考信号作为样本滤除目标回波中的杂波,但由于雨、云、树木或其他运动物体等的影响,回波内可能会包含非零频杂波,导致处理后杂波残余较大,影响目标检测。针对上述问题,提出了一种基于杂波识别的扩展最小均方(Least Mean Square,LMS)对消算法。首先利用模糊函数估计杂波的频率和时延分布,构建含频率信息的多个参考信号。再把多个参考信号插入LMS算法中推导了扩展LMS算法,利用扩展LMS算法可以同时对消静、动杂波。扩展LMS算法能降低对消剩余,提高目标的信噪比,仿真分析和实测数据处理验证了算法的有效性。展开更多
基金supported by the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-YWJC402)the Hundred Talents Program of Chinese Academy of Sciences(No.A0815)+1 种基金the National Natural Science Foundation of China(No.41371474)supported by the Chinese Academy of Sciences Visiting Professorships for Senior International Scientists in 2011(No.2011T2Z18)
文摘Integrating land use type and other geographic information within spatial interpolation has been proposed as a solution to improve the performance and accuracy of soil nutrient mapping at the regional scale. This study developed a non-algorithm approach, i.e., applying inverse distance weighting （IDW） and ordinary kriging （OK）, to individual land use types rather than to the whole watershed, to determine if this improved the performance in mapping soil total C （TC）, total N （TN）, and total P （TP） in a 200-km2 urbanizing watershed in Southeast China. Four land use types were identified by visual interpretation as forest land, agricultural land, green land, and urban land. One hundred and fifty soil samples （0-10 cm） were taken according to land use type and patch size. Results showed that the non-algorithm approach, interpolation based on individual land use types, substantially improved the performance of IDW and OK for mapping TC, TN, and TP in the watershed. Root mean square errors were reduced by 3.9% for TC, 10.770 for TN, and 25.9% for TP by the application of IDW, while the improvements by OK were slightly lower as 0.9% for TC, 7.7% for TN, and 18.1% for TP. Interpolations based on individual land use types visually improved depiction of spatial patterns for TC, TN, and TP in the watershed relative to interpolations by the whole watershed. Substantial improvements might be expected with denser sampling points. We suggest that this non-algorithm approach might provide an alternative to algorithm-based approaches to depict watershed-scale nutrient patterns.
文摘在工业化建造和碳减排的背景下,预制装配化得到了极大关注。以装配式铁路桥梁为对象,首先,考虑4种典型构件类型(箱梁、桥面板、桥墩和盖梁),核算其预制与现浇两种方式在物化阶段的立方单项碳排放和建造成本,并构建以构件预制率为决策变量的碳排放-成本双目标优化模型,系统优化预制构件的选择与组合;其次,采用非支配排序的鲸鱼优化算法(Non-Dominated Sorting Whale Optimization Algorithm,NSWOA)对构件组合方案进行求解,获得Pareto均衡解集;再次,通过博弈论思想融合主客观权重,并采用优劣解距离法(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)对Pareto均衡解集进行科学决策,得到最佳构件组合方案;最后,以某西部装配式铁路桥梁为例开展实证分析。结果显示:优化方案较初始方案碳排放减少了361.66 t,成本减少了213.06万元。此外,预制率情景分析显示,不同的桥梁预制率对应不同的最佳构件组合,且碳排放与成本随预制率变化呈现不同趋势。研究成果可为装配式铁路桥梁低碳施工提供有效的优化策略。
文摘外辐射源雷达利用直达天线接收的参考信号作为样本滤除目标回波中的杂波,但由于雨、云、树木或其他运动物体等的影响,回波内可能会包含非零频杂波,导致处理后杂波残余较大,影响目标检测。针对上述问题,提出了一种基于杂波识别的扩展最小均方(Least Mean Square,LMS)对消算法。首先利用模糊函数估计杂波的频率和时延分布,构建含频率信息的多个参考信号。再把多个参考信号插入LMS算法中推导了扩展LMS算法,利用扩展LMS算法可以同时对消静、动杂波。扩展LMS算法能降低对消剩余,提高目标的信噪比,仿真分析和实测数据处理验证了算法的有效性。
