智能电表故障的准确预测对实现计量设备精准主动运维、保障电网稳定运行具有重要意义。电表各故障类型样本的出现频次不同,且不同故障类型样本在高维特征空间中的分布存在重叠,这极大增加了故障预测的难度。现有不平衡分类方法通过构建...智能电表故障的准确预测对实现计量设备精准主动运维、保障电网稳定运行具有重要意义。电表各故障类型样本的出现频次不同,且不同故障类型样本在高维特征空间中的分布存在重叠,这极大增加了故障预测的难度。现有不平衡分类方法通过构建单一样本信息与其对应类别标签的映射关系来划分样本类型,导致对具有相似表征信息的重叠区样本难以准确判别,降低了整体分类精度。该文提出一种基于多粒度近邻图的智能电表故障分类方法。首先,选择原始数据集中样本作为目标样本,以目标样本及其近邻样本作为节点、目标样本与其近邻样本连线作为边构建近邻图。根据选择的近邻样本数量不同构建多粒度近邻图,实现目标样本的信息扩充和训练样本的数量扩增,更有利于模型稳定训练。构建编码器挖掘近邻图节点特征,利用图注意力机制,根据近邻图节点编码特征和节点邻接关系将近邻样本信息自适应地聚合到目标样本,实现对相似样本差异的有效挖掘。对于给定测试样本,通过集成测试样本多粒度近邻图的分类结果,得到更精准、更鲁棒的智能电表故障预测结果。在20个KEEL(knowledge extraction based on evolutionary learning)和UCI(UC Irvine machine learning repository)不平衡分类公开数据集和智能电表实际故障数据集上的大量实验结果表明,与17种典型方法相比,该文所提算法在处理智能电表故障分类问题上具有显著优势。展开更多
“十四五”期间“双碳”目标的提出,推动着我国基础设施建设向绿色低碳的方向发展,生命周期评价方法(LCA)作为一款全面的环境影响评价工具逐渐开始应用到我国建筑业。以生命周期评价理论为基础,选取长江上游某内河港口工程为研究对象,...“十四五”期间“双碳”目标的提出,推动着我国基础设施建设向绿色低碳的方向发展,生命周期评价方法(LCA)作为一款全面的环境影响评价工具逐渐开始应用到我国建筑业。以生命周期评价理论为基础,选取长江上游某内河港口工程为研究对象,将该港口工程全生命周期划分为施工阶段、运维阶段及退役阶段进行碳排放来源分析并估算碳排放。结果表明,该港口工程全生命周期碳排放为8.67万t CO_(2)-eq(当量),施工阶段、运维阶段、退役阶段分别占比39.4%、56.7%、3.9%,单位碳排放为95%置信区间为651.92~745.21 kg CO_(2)-eq/m^(2),中位数为698.14 kg CO_(2)-eq/m^(2),清单数据不确定性较小,港口工程碳排放敏感因素为混凝土和电力。碳排放评价结果总体较好,可作为后续制定碳减排政策的相关依据。展开更多
Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle...Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle-dependent HDPC,it is found that the HDPC is mainly contributed by the circular photogalvanic effect(CPGE)current when the incident plane is perpendicular to the connection of the two contacts,whereas the circular photon drag effect(CPDE)dominates the HDPC when the incident plane is parallel to the connection of the two contacts.In addition,the CPGE of the(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate is regulated by temperature,light power,excitation wavelength,the source–drain and ionic liquid top-gate voltages,and the regulation mechanisms are discussed.It is demonstrated that(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplates may provide a good platform for novel opto-spintronics devices.展开更多
文摘智能电表故障的准确预测对实现计量设备精准主动运维、保障电网稳定运行具有重要意义。电表各故障类型样本的出现频次不同,且不同故障类型样本在高维特征空间中的分布存在重叠,这极大增加了故障预测的难度。现有不平衡分类方法通过构建单一样本信息与其对应类别标签的映射关系来划分样本类型,导致对具有相似表征信息的重叠区样本难以准确判别,降低了整体分类精度。该文提出一种基于多粒度近邻图的智能电表故障分类方法。首先,选择原始数据集中样本作为目标样本,以目标样本及其近邻样本作为节点、目标样本与其近邻样本连线作为边构建近邻图。根据选择的近邻样本数量不同构建多粒度近邻图,实现目标样本的信息扩充和训练样本的数量扩增,更有利于模型稳定训练。构建编码器挖掘近邻图节点特征,利用图注意力机制,根据近邻图节点编码特征和节点邻接关系将近邻样本信息自适应地聚合到目标样本,实现对相似样本差异的有效挖掘。对于给定测试样本,通过集成测试样本多粒度近邻图的分类结果,得到更精准、更鲁棒的智能电表故障预测结果。在20个KEEL(knowledge extraction based on evolutionary learning)和UCI(UC Irvine machine learning repository)不平衡分类公开数据集和智能电表实际故障数据集上的大量实验结果表明,与17种典型方法相比,该文所提算法在处理智能电表故障分类问题上具有显著优势。
文摘“十四五”期间“双碳”目标的提出,推动着我国基础设施建设向绿色低碳的方向发展,生命周期评价方法(LCA)作为一款全面的环境影响评价工具逐渐开始应用到我国建筑业。以生命周期评价理论为基础,选取长江上游某内河港口工程为研究对象,将该港口工程全生命周期划分为施工阶段、运维阶段及退役阶段进行碳排放来源分析并估算碳排放。结果表明,该港口工程全生命周期碳排放为8.67万t CO_(2)-eq(当量),施工阶段、运维阶段、退役阶段分别占比39.4%、56.7%、3.9%,单位碳排放为95%置信区间为651.92~745.21 kg CO_(2)-eq/m^(2),中位数为698.14 kg CO_(2)-eq/m^(2),清单数据不确定性较小,港口工程碳排放敏感因素为混凝土和电力。碳排放评价结果总体较好,可作为后续制定碳减排政策的相关依据。
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62074036,61674038,and 11574302)the Foreign Cooperation Project of Fujian Province,China(Grant No.2023I0005)+2 种基金the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF202108)the National Key Research and Development Program of China(Grant No.2016YFB0402303)the Foundation of Fujian Provincial Department of Industry and Information Technology of China(Grant No.82318075)。
文摘Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle-dependent HDPC,it is found that the HDPC is mainly contributed by the circular photogalvanic effect(CPGE)current when the incident plane is perpendicular to the connection of the two contacts,whereas the circular photon drag effect(CPDE)dominates the HDPC when the incident plane is parallel to the connection of the two contacts.In addition,the CPGE of the(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate is regulated by temperature,light power,excitation wavelength,the source–drain and ionic liquid top-gate voltages,and the regulation mechanisms are discussed.It is demonstrated that(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplates may provide a good platform for novel opto-spintronics devices.