一种改进基于瞬时无功功率的谐波电流检测方法

我国电力系统大多数处在不平衡状态下，文章对现有的基于瞬时无功功率谐波的检测方法进行改进，并采用瞬时无功功率闭环检测，使检测系统鲁棒性强、稳定度好。仿真结果验证了该方法的实用性及可行性。     

论品牌逆淘汰现象及其治理

品牌逆淘汰不仅给消费者带来了巨大的经济损失,更给经济秩序和社会风尚造成了极大的负面影响。品牌逆淘汰是市场经济中违反正常竞争规则、违背协议道德的非理性行为,往往表现为品牌失信。它源于市场竞争规制失范,协议道德失守,也受制于社会的潜规则。要根治品牌逆淘汰,除了强化政府对商业环境的治理,重塑合理的、有序的"竞争空间",还要全社会共同努力,净化社会风尚。     

基于子孔径方位特性的穿墙雷达虚拟多视角成像方法

针对穿墙雷达(TWR)室内不规则场景中信号传播的多径效应所导致成像区域“幻影”存在的问题，提出了一种基于脉冲雷达信号平台频域压缩感知(CS)框架的多径利用方法。在建立室内多径回波脉冲信号矢量模型的基础上，将每条多径分量作为一个特殊的观测通道，并利用目标、多径“幻影”依赖于阵列子孔径方位(AD)的特性，由此来分析目标、“幻影”与子孔径位置的关联性，最后通过调和平均(HMAM)子孔径图像融合方法实现 “幻影”抑制和目标的虚拟多视角成像。该方法克服了脉冲信号时域压缩感知计算复杂度高以及需要事先已知室内几何反射位置的不足。不同场景的仿真结果验证了此方法的可行性和优越性。     

单位球上调和Dirichlet空间上的分式线性复合算子

研究了单位球上调和Dirichlet空间上的分式线性复合算子的伴随表示,并在此基础上讨论了空间■h(BN)和■h0(BN)上的分式线性复合算子的正常性与本性正常性.     

Analyzing driving factors of land values in urban scale based on big data and non-linear machine learning techniques

Land value plays a vital role in the real estate market. It is a critical reference for urban planners to reallocate land resources and introduce valid policies. Studying the influential factors on land value can help better understand the spatial-temporal variation of land values and design effective control policies. This attracted a number of scholars to study the spatial and temporal relationships between land value and its possible influential factors from the perspective of macro and micro. However, the majority of the existing studies have the problems of linear assumption and multicollinearity in research models. Limited features and the lack of feature selection procedure are another two commonly seen limitations. To overcome the gaps, this paper adopts non-linear machine learning (ML) methods to investigate the influential factors on land values per square foot based on “big data” in New York City. More than one thousand potential factors are considered, covering from the land attribute, point of interest, demographics, housing, to economic, education, and social. They are further selected using a feature extraction model named Recursive Feature Elimination (RFE). Six ML algorithms, including Random Forest (RF), Gradient Boosting Decision Tree (GBDT), Multi Linear Regression (MLR), Linear Support Vector Regression (SVR), Multilayer Perceptron (MLP) Regression, and K-Nearest Neighbor (KNN) Regression are evaluated and compared. The optimal one with an R-square value of 0.933 is used to calculate the feature importance further. Several important impact features are disclosed, including the number of newsstands, and the vacant housing percentage.     

浅谈煤矿企业的无功补偿与谐波治理

首先分析煤矿企业供电面临的关键问题,明确传统的电容器型补偿器的应用缺陷,提出无功补偿的概念,并重点分析SVC的运行模式,最后结合应用实例分析该装置的技术优势。     

Randomization in the Design of Experiments

A general review is given of the role of randomization in experimental design. Three objectives are distinguished, the avoidance of bias, the establishment of a secure base for the estimation of error in traditional designs, and the provision of formally exact tests of significance and confidence limits. The approximate randomization theory associated with analysis of covariance is outlined and conditionality considerations are used to explain the limited role of randomization in experiments with very small numbers of experimental units. The relation between the so-called design-based and model-based analyses is discussed. Corresponding results in sampling theory are mentioned briefly.     

软弱地基的松木桩处理在水库除险加固工程中的应用

文章结合笔者的工程实践,对用松木桩处理软弱地基的问题进行探讨。阐述了该方法的经济性、适用范围、效果及可行性,希望能为以后同类工程的施工提供借鉴。     

逆向淘汰、财政补贴与农业的低效率发展——基于湘北农村的调查研究

农村社会劳动力转移的逆向淘汰趋势将使我国的农业逐渐失去自生能力,而不具备自生能力的农业经济组织是不能依靠财政补贴提高经济效率的。如果在劳动力逆向淘汰使农业生产失去活力的条件下,政府提高对农业的财政补贴,势必导致我国的农业发展陷入低效率均衡的陷阱。     

基于政策实践的广东立体化旅游扶贫模式探析

本文立足于广东旅游扶贫政策实践，对其率先探索并创造的在全省范围内开展的立体化旅游扶贫模式进行了系统研究，探讨了该模式的内涵特色和运行机制，将其与国内其他旅游扶贫模式进行了对比分析，总结了广东旅游扶贫工程的经验与启示。