Wave shapes that induce velocity skewness and acceleration asymmetry are usually responsible for onshore sediment transport, whereas undertow and bottom slope effect normally contribute to offshore sediment transport....Wave shapes that induce velocity skewness and acceleration asymmetry are usually responsible for onshore sediment transport, whereas undertow and bottom slope effect normally contribute to offshore sediment transport. By incorporating these counteracting driving forces in a phase-averaged manner, the theoretically-based quasi-steady formula of Wang （2007） is modified to predict the magnitude and direction of net cross-shore total load transport under the coaction of wave and current. The predictions show an excellent agreement with the measurement data on medium and fine sand collected by Dohmen-Janssen and Hanes （2002） and Schretlen （2012） in a full-scale wave flume at the Coastal Research Centre in Hannover, Germany. The modified formula can predict the net onshore transport of fine sand in sheet flows. In particular, it can predict the net offshore transport of medium sand in rippled beds through enlarged bed roughness, as well as the net offshore transport of fine-to-coarse sand in sheet flows with the aid of a new criterion to judge the occurrence of net offshore transport.展开更多
智能电网的发展认识到短期电力净负荷预测对综合能源系统(integrated energy system,IES)的重要性。净负荷预测代表用电负荷与安装的可再生能源之间的差异,是能量管理和优化调度的基础。为解决IES波动性大,传统统计模型预测精较差的问题...智能电网的发展认识到短期电力净负荷预测对综合能源系统(integrated energy system,IES)的重要性。净负荷预测代表用电负荷与安装的可再生能源之间的差异,是能量管理和优化调度的基础。为解决IES波动性大,传统统计模型预测精较差的问题,该文提出一种基于时空图卷积网络(spatial temporal graph convolutional networks,STGCN)和Transformer相结合的综合能源系统短期负荷预测模型。首先,利用STGCN作为输入嵌入层对多元输入序列进行编码,填补Transformer中没有充分考虑相关信息的空白。然后,利用Transformer中的自注意机制捕获序列数据的时间依赖性。最后,利用前馈神经网络输出预测负荷值。以浙江省某地区电力数据集为例,与其他4种预测模型相比较平均绝对百分比误差均在5%以内,结果表明该文模型具有较高的预测精度和稳定性。展开更多
提出了一种基于.NET的电力负荷预测系统总体架构,并对本系统的需求分析、整体架构和安全性设计进行了阐述。按照软件工程规范的要求,详细设计了系统各功能模块:负荷分析、负荷预测、数据接收与上报管理、考核管理、数据查询与报表管理...提出了一种基于.NET的电力负荷预测系统总体架构,并对本系统的需求分析、整体架构和安全性设计进行了阐述。按照软件工程规范的要求,详细设计了系统各功能模块:负荷分析、负荷预测、数据接收与上报管理、考核管理、数据查询与报表管理、系统维护等六个模块。重点阐述了系统实现的关键技术,如NetAdvantage组件、XML Web Service技术和负荷数据读取实现。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51179211)
文摘Wave shapes that induce velocity skewness and acceleration asymmetry are usually responsible for onshore sediment transport, whereas undertow and bottom slope effect normally contribute to offshore sediment transport. By incorporating these counteracting driving forces in a phase-averaged manner, the theoretically-based quasi-steady formula of Wang （2007） is modified to predict the magnitude and direction of net cross-shore total load transport under the coaction of wave and current. The predictions show an excellent agreement with the measurement data on medium and fine sand collected by Dohmen-Janssen and Hanes （2002） and Schretlen （2012） in a full-scale wave flume at the Coastal Research Centre in Hannover, Germany. The modified formula can predict the net onshore transport of fine sand in sheet flows. In particular, it can predict the net offshore transport of medium sand in rippled beds through enlarged bed roughness, as well as the net offshore transport of fine-to-coarse sand in sheet flows with the aid of a new criterion to judge the occurrence of net offshore transport.
文摘提出了一种基于.NET的电力负荷预测系统总体架构,并对本系统的需求分析、整体架构和安全性设计进行了阐述。按照软件工程规范的要求,详细设计了系统各功能模块:负荷分析、负荷预测、数据接收与上报管理、考核管理、数据查询与报表管理、系统维护等六个模块。重点阐述了系统实现的关键技术,如NetAdvantage组件、XML Web Service技术和负荷数据读取实现。
