Applying Feature-Weighted Gradient Decent K-Nearest Neighbor to Select Promising Projects for Scientific Funding

Due to its outstanding ability in processing large quantity and high-dimensional data, machine learning models have been used in many cases, such as pattern recognition, classification, spam filtering, data mining and forecasting. As an outstanding machine learning algorithm, K-Nearest Neighbor (KNN) has been widely used in different situations, yet in selecting qualified applicants for winning a funding is almost new. The major problem lies in how to accurately determine the importance of attributes. In this paper, we propose a Feature-weighted Gradient Decent K-Nearest Neighbor (FGDKNN) method to classify funding applicants in to two types: approved ones or not approved ones. The FGDKNN is based on a gradient decent learning algorithm to update weight. It updatesthe weight of labels by minimizing error ratio iteratively, so that the importance of attributes can be described better. We investigate the performance of FGDKNN with Beijing Innofund. The results show that FGDKNN performs about 23%, 20%, 18%, 15% better than KNN, SVM, DT and ANN, respectively. Moreover, the FGDKNN has fast convergence time under different training scales, and has good performance under different settings.     

广西钨钼矿成矿规律

广西地处古中国构造域南端,是中国著名的有色金属基地,钨钼资源较丰富。广西钨钼矿矿床类型以热液脉型和矽卡岩型为主,成矿时代分布较广,包括加里东晚期、印支晚期及燕山晚期,区内大型钨钼矿床主要成矿于燕山期。钨钼矿床的空间分布与构造和岩浆岩关系密切,区域性断裂和富含W、Mo等成矿元素的复式岩体对成矿更加有利。本文对广西区内主要钨钼矿床进行了梳理,总结了广西钨钼矿成矿规律,并以典型钨钼矿床特征为依据,划分了11个矿床成矿系列,对区内下一步找矿具有指导意义。     

光伏逆变器短路电流3次谐波及其对保护的影响分析

系统发生不对称故障时,短路电流、电压中出现负序分量,导致光伏逆变器直流母线电压中产生二倍频振荡,该振荡分量经过控制回路流通后将在光伏逆变器输出短路电流中生成3次谐波。推导了逆变器输出短路电流3次谐波的解析表达式,计及光伏逆变器的限幅控制特性、负序控制策略、低电压穿越策略,研究了3次谐波的变化特性,然后分析了3次谐波对变压器差动保护电流互感器饱和判据的影响,指出某些工况下光伏逆变器输出短路电流中的3次谐波含量较大,可能造成变压器差动保护误闭锁,导致变压器区内故障无法切除,并提出了相应的应对策略。大量的仿真试验结果验证了理论分析的正确性。     

带标签信息子字典级联学习的复合电能质量扰动识别方法

针对传统字典学习方法的训练样本信号单一、重构效果差等缺点,提出一种带标签信息子字典级联的学习方法,对电能质量扰动信号进行扰动识别。该方法首先对不同类别电能质量扰动测试和训练样本采用主成分分析方法进行降维特征提取,对训练样本添加标签信息,其次对不同类别的电能质量样本训练成冗余子字典并级联成结构化字典,最后将级联的字典优化学习并由冗余误差最小值来判断目标的归属类别。仿真实验结果表明,该方法下的识别效果优于支持向量机(SVM)和稀疏表达分类(SRC),抗噪声鲁棒性更强,在信噪比20 dB以上的环境中电能质量复合扰动识别率达到91.40%以上。     

氯乙烯合成节能与环保技术的发展现状

概述了近期国内氯乙烯合成精馏尾气处理、氯化汞触媒降耗及废液处理等技术的发展现状和创新成果,并对各种技术的特点、企业应用效果进行了简单的介绍。     

Fabrication of novel silicon carbide-based nanomaterials with unique hydrophobicity and microwave absorption property

Novel SiC-based nanomaterials, namely the nitrogen and aluminum co-doped SiC@SiO₂ core-shell nanowires and nitrogen-doped SiO₂/Al₂O₃ nanoparticles, have been fabricated through a facile thermal treatment process based on the chemical vapor deposition and vapor-liquid reaction. These nanomaterials show remarkable hydrophobicity with a water contact angle (CA) over 140°, which are aroused by the surface zigzag morphology of the nanostructures and the hydrocarbyl groups generated during the preparation process. Moreover the nanocomposites also exhibit relatively prominent microwave absorption (MA) properties in the frequency range of 2.0-18.0 GHz. The minimum reflection loss (RL) value as low as −23.68 dB can be observed at 14.16 GHz when the absorber thickness is 2.6 mm with a loading rate of 16.7 wt%. And the nanocomposites-based absorbent can achieve an effective absorption bandwidth (RL < −10 dB) of 4.48 GHz with the absorbent thickness of 2.5 mm. This enhanced microwave attenuation performance can be attributed to multiple polarizations and perfect impedance matching conditions, as well as multiple internal reflections. These marvelous properties make these N and Al co-doped SiC@SiO₂ core-shell nanowires and N-doped SiO₂/Al₂O₃ nanoparticles display extensive application potential as MA materials in harsh environment.     

基于DSP的轨道移频信号解调实现

提出了以双路TMS320F2812为核心,接收解调ZPW-2000A的FSK信号.前端通过信号调理,利用DSP内部的AD对FSK信号采样.经过FFT变换解调出载频频率、Z-F盯解调低频频率,以及通过DSP的SPI口.对两路解调出的信号进行比较,若一致,则输出.该设计采用双机热备,使系统的工作可靠性更强.结果证明,系统有...     

多元易发泡型复合乳化剂乳化炸药的制备

文章论述了一种多元易发泡型复合乳化剂,它含水溶性和油溶性两种类型的乳化剂,能将内相中硝酸铵溶液极个别硝酸铵分子外移至外相,与亚硝酸钠水溶液NO2相遇后,即产生气泡（N2）,使乳胶基质敏化成乳化炸药,消除了化学敏化中二元敏化、后效及混合不均匀的问题。     

分段空场嗣后充填采矿法安全高效开采工艺实践

以某黄金矿山为实例,介绍了分段空场嗣后充填采矿法安全高效开采工艺应用,包括采切工程布置、回采工艺流程及参数、采矿设备等,并叙述了采空区CMS探测及残矿回采设计过程。该矿山多年的开采实践表明,该采矿方法能大幅度提高生产能力,降低综合成本,提高作业安全,实现矿体开采的安全、高效、经济的技术目标。