在茶园水资源管理中,蒸散量(Evapotranspiration,ET)是评估作物水分需求的关键指标,由于茶园蒸散量预测具有时序性、不稳定性以及非线性耦合等特点,目前的茶园蒸散量预测模型存在预测精度较低的问题,针对此问题本文提出了一种新型的茶...在茶园水资源管理中,蒸散量(Evapotranspiration,ET)是评估作物水分需求的关键指标,由于茶园蒸散量预测具有时序性、不稳定性以及非线性耦合等特点,目前的茶园蒸散量预测模型存在预测精度较低的问题,针对此问题本文提出了一种新型的茶园蒸散量预测模型。首先使用互信息算法(Mutual information,MI)与主成分分析算法(Principal component analysis,PCA)相融合的数据处理算法(MIPCA),筛选强相关的特征并提取主成分;其次将时域卷积网络(Temporal convolutional network,TCN)与Transformer融合,利用灰狼算法(Grey wolf optimization,GWO)优化超参数,捕捉茶园数据的全局依赖关系;最后整合2个网络构建了MIPCA-TCN-GWO-Transformer模型,通过消融试验和对比试验验证了模型性能,并对模型在不同时间步长下的性能进行测试。结果表明,该模型平均绝对百分比误差(Mean absolute percentage error,MAPE)、均方根误差(Root mean square error,RMSE)和决定系数(Coefficient of determination,R^(2))3个评价指标分别为0.015 mm/d、0.312 mm/d和0.962,优于长短期记忆模型(Long short term memory,LSTM)等传统预测模型。在小时尺度、日尺度和月尺度下的R^(2)分别为0.986、0.978和0.946,在不同时间步长下展现了良好的适应性和准确性。本文构建的MIPCA-TCN-GWO-Transformer模型具有较高的预测精度和稳定性,可为茶园水资源优化管理和灌溉制度制定提供科学参考。展开更多
In this paper,using the research method of grounded theory,with the competitive brand of home gardening—Hongyue Garden Maker as the specific object of study,we collect the data through interviews and surveys,conduct ...In this paper,using the research method of grounded theory,with the competitive brand of home gardening—Hongyue Garden Maker as the specific object of study,we collect the data through interviews and surveys,conduct coding analysis step by step on the data,establish the brand asset creation path model consisting of some main dimensions including " brand salience"," brand performance"," brand image"," brand judgment"," brand feeling",and " brand resonance",and reveal the interaction and logical relationship between the above dimensions,so as to provide theoretical support for the asset creation of many kinds of home gardening and other brands.展开更多
TOptimization of regional landscape pattern is significant for improving function and value of ecosystem,and restraining the expansion of urban layout.Taking Chengdu City for example,this paper applied RS and GIS tech...TOptimization of regional landscape pattern is significant for improving function and value of ecosystem,and restraining the expansion of urban layout.Taking Chengdu City for example,this paper applied RS and GIS techniques,landscape indexes and ecological service function evaluation to further analyze the temporal and spatial characteristics of landscape pattern and spatial differences of regional ecological functions,and on this basis,identified the spatial distribution of ecological source lands.Based on the long-term objective of building Chengdu into a modem garden city,this paper applied the accumulative cost distance model and introduced garden city theory to construct regional ecological corridors and ecological nodes,and explored the approaches of optimizing landscape pattern of modem garden city.The results showed that a great deal of arable land has been transferred to construction land in the urbanization;intensity of regional ecological functions showed obvious spatial differences;ecological source lands were mainly distributed in the Longmen Mountain,the Qionglai Mountain,the Changqiu Mountain and the Longquan Mountain;according to actual conditions of the study area,the road ecological corridors,river corridors and agricultural corridors in the layout of "four rings and six radial corridors" were constructed;ecological nodes dominated by intersection,wetland and forest park were formed.This research method and results are significant references for building Chengdu into a modem garden展开更多
社区花园作为新兴起的一种城市绿地形式,以其自发性强、参与性高等特点成为城市居民营建可食景观的首选方式。但近年来的研究发现,社区花园土壤存在来源复杂、性质不稳定等城市棕地的特点,其土壤质量可能影响可食植物的安全性。因此,针...社区花园作为新兴起的一种城市绿地形式,以其自发性强、参与性高等特点成为城市居民营建可食景观的首选方式。但近年来的研究发现,社区花园土壤存在来源复杂、性质不稳定等城市棕地的特点,其土壤质量可能影响可食植物的安全性。因此,针对近10年来国内外社区花园土壤及其治理方式进行梳理,基于Web of Science(WOS)和中国知网(CNKI)数据库,利用CiteSpace分析其热点主题、发文量和发展趋势等,从问题表征、研究对象与方法、理论与技术层面分析其研究现状与进展。在此基础上,对社区花园土壤存在的问题与治理方法进行总结。研究表明:社区花园用地属性不明,土壤现状复杂多变,存在以重金属、多环芳烃等为主的土壤污染,可能会对人体健康产生危害;土壤养分低,有干旱和碱化趋势;现阶段社区花园土壤治理方法以植物修复为主,多种技术联合为辅。研究结果可为社区花园的建设、管理和维护提供借鉴与参考。展开更多
文摘在茶园水资源管理中,蒸散量(Evapotranspiration,ET)是评估作物水分需求的关键指标,由于茶园蒸散量预测具有时序性、不稳定性以及非线性耦合等特点,目前的茶园蒸散量预测模型存在预测精度较低的问题,针对此问题本文提出了一种新型的茶园蒸散量预测模型。首先使用互信息算法(Mutual information,MI)与主成分分析算法(Principal component analysis,PCA)相融合的数据处理算法(MIPCA),筛选强相关的特征并提取主成分;其次将时域卷积网络(Temporal convolutional network,TCN)与Transformer融合,利用灰狼算法(Grey wolf optimization,GWO)优化超参数,捕捉茶园数据的全局依赖关系;最后整合2个网络构建了MIPCA-TCN-GWO-Transformer模型,通过消融试验和对比试验验证了模型性能,并对模型在不同时间步长下的性能进行测试。结果表明,该模型平均绝对百分比误差(Mean absolute percentage error,MAPE)、均方根误差(Root mean square error,RMSE)和决定系数(Coefficient of determination,R^(2))3个评价指标分别为0.015 mm/d、0.312 mm/d和0.962,优于长短期记忆模型(Long short term memory,LSTM)等传统预测模型。在小时尺度、日尺度和月尺度下的R^(2)分别为0.986、0.978和0.946,在不同时间步长下展现了良好的适应性和准确性。本文构建的MIPCA-TCN-GWO-Transformer模型具有较高的预测精度和稳定性,可为茶园水资源优化管理和灌溉制度制定提供科学参考。
基金Supported by National College Students'Innovation and Entrepreneurship Training Program in 2017(103-2013200072)National Social Science Fund Project(15BGL088)Zhejiang Higher Education Reform Project in 2016(jg20160092)
文摘In this paper,using the research method of grounded theory,with the competitive brand of home gardening—Hongyue Garden Maker as the specific object of study,we collect the data through interviews and surveys,conduct coding analysis step by step on the data,establish the brand asset creation path model consisting of some main dimensions including " brand salience"," brand performance"," brand image"," brand judgment"," brand feeling",and " brand resonance",and reveal the interaction and logical relationship between the above dimensions,so as to provide theoretical support for the asset creation of many kinds of home gardening and other brands.
基金Sponsored by National"Twelfth Five-year Plan"Science and Technology Support Program(2012BAJ21B08)Program of the Ministry of Environmental Protection
文摘TOptimization of regional landscape pattern is significant for improving function and value of ecosystem,and restraining the expansion of urban layout.Taking Chengdu City for example,this paper applied RS and GIS techniques,landscape indexes and ecological service function evaluation to further analyze the temporal and spatial characteristics of landscape pattern and spatial differences of regional ecological functions,and on this basis,identified the spatial distribution of ecological source lands.Based on the long-term objective of building Chengdu into a modem garden city,this paper applied the accumulative cost distance model and introduced garden city theory to construct regional ecological corridors and ecological nodes,and explored the approaches of optimizing landscape pattern of modem garden city.The results showed that a great deal of arable land has been transferred to construction land in the urbanization;intensity of regional ecological functions showed obvious spatial differences;ecological source lands were mainly distributed in the Longmen Mountain,the Qionglai Mountain,the Changqiu Mountain and the Longquan Mountain;according to actual conditions of the study area,the road ecological corridors,river corridors and agricultural corridors in the layout of "four rings and six radial corridors" were constructed;ecological nodes dominated by intersection,wetland and forest park were formed.This research method and results are significant references for building Chengdu into a modem garden
文摘社区花园作为新兴起的一种城市绿地形式,以其自发性强、参与性高等特点成为城市居民营建可食景观的首选方式。但近年来的研究发现,社区花园土壤存在来源复杂、性质不稳定等城市棕地的特点,其土壤质量可能影响可食植物的安全性。因此,针对近10年来国内外社区花园土壤及其治理方式进行梳理,基于Web of Science(WOS)和中国知网(CNKI)数据库,利用CiteSpace分析其热点主题、发文量和发展趋势等,从问题表征、研究对象与方法、理论与技术层面分析其研究现状与进展。在此基础上,对社区花园土壤存在的问题与治理方法进行总结。研究表明:社区花园用地属性不明,土壤现状复杂多变,存在以重金属、多环芳烃等为主的土壤污染,可能会对人体健康产生危害;土壤养分低,有干旱和碱化趋势;现阶段社区花园土壤治理方法以植物修复为主,多种技术联合为辅。研究结果可为社区花园的建设、管理和维护提供借鉴与参考。
