中高压软启动控制器的设计

直接启动电动机会产生很强的冲击电流,降低了电动机的使用寿命,对电网也会造成很大的冲击.设计一种限流PI调节降压式软启动,该软启动以TMS320 F28335为控制核心,通过在同步信号作用下,采集电动机启动时电流、电压信号,对晶闸管触发角移相的控制实现电动机启动电压和电流的调节,电动机启动过程中的参数可以根据电动机不同负...     

一种改进的SVM算法在决策分析中的应用

决策支持系统是跨学科的综合体系,涉及机器学习理论。支持向量机是近几年发展起来的学习方法,它是利用最优分类面（线）将两类样本在特征空间或输入空间中无错误地分开,而且要使两类的分类空隙最大。然而当两类中的样本数量差剐悬殊时,支持向量机的分类能力会下降。为了解决此问题,本文提出了一种改选的支持向量机算法,在所开发的医学决策支持系统上的应用表明,此方法在解决两类样本数量十分不均衡问题时有着很强的分类能力,不失为一种有效的决策分析工具。     

基于SUMO和WordNet本体集成的文本分类模型研究

针对传统文本分类方法和目前语义分类方法中存在的问题,提出基于SUMO和WordNet本体集成的文本分类模型,该模型利用WordNet同义词集与SUMO本体概念之间的映射关系,将文档-词向量空间中的词条映射成本体中相应的概念,形成文档-概念向量空间进行文本自动分类。实验表明,该方法能够极大降低向量空间维度,提高文本分类性能。     

Kinetic regulation of MXene with water-in-LiCl electrolyte for high-voltage micro-supercapacitors

MXenes are one of the key materials for micro-supercapacitors (MSCs), integrating miniaturized energy-storage components with microelectronics. However, the energy densities of MSCs are greatly hampered by MXenes’ narrow working potential window (typically ≤0.6 V) in aqueous electrolytes. Here, we report the fabrication of high-voltage MXene-MSCs through the efficient regulation of reaction kinetics in 2D Ti₃C₂T_x MXene microelectrodes using a water-in-LiCl (WIL, 20 m LiCl) salt gel electrolyte. Importantly, the intrinsic energy-storage mechanism of MXene microelectrodes in WIL, which is totally different from traditional electrolytes (1 m LiCl), was revealed through insitu and exsitu characterizations. We validated that the suppression of MXene oxidation at high anodic potential occurred due to the high content of WIL regulating anion intercalation in MXene electrodes, which effectively broadened the voltage window of MXene-MSCs. Remarkably, the symmetric planar MXene-MSCs presented a record operating voltage of 1.6 V, resulting in an exceptionally high volumetric energy density of 31.7 mWh cm⁻³. With the ultra-high ionic conductivity (69.5 mS cm⁻¹) and ultralow freezing point (−57°C) of the WIL gel electrolyte, our MSCs could be operated in a wide temperature range of −40 to 60°C, and worked for a long duration even at −40°C, demonstrative of its practicality in extreme environments.     

自动电压控制(AVC)系统的设计原则

介绍基于EMS系统的自动电压控制(AVC)系统的设计原则,分析其控制原理以及各种不同的控制模式。     

基于字词向量的多尺度卷积神经网络微博评论的情感分类模型及实验研究

[目的/意义]微博评论情感分类模型可以为相关舆情监管部门正确管控话题事件的发展状况和舆情提供一定的指导作用。[方法/过程]基于字词向量的多尺度卷积神经网络，运用多尺度卷积核改善微博评论中上下文信息有限的条件制约，构建基于字词向量的多尺度卷积神经网络微博评论情感分类模型；通过爬取"微博热搜整改"数据，对模型的可行性和优越性进行验证。[结果/结论]验证结果表明基于字词向量的多尺度卷积神经网络在微博舆情等上下文信息有限的短文本分类任务中表现良好。本文在理论层面为微博舆情情感分类提供了更为准确的情感分类理论模型及分类方法，在实践层面可以更好地指导舆情监管部门对舆情的情感倾向进行更好的引导和监管。     

A novel intelligent classification model for breast cancer diagnosis

Breast cancer is one of the leading causes of death among women worldwide. Accurate and early detection of breast cancer can ensure long-term surviving for the patients. However, traditional classification algorithms usually aim only to maximize the classification accuracy, failing to take into consideration the misclassification costs between different categories. Furthermore, the costs associated with missing a cancer case (false negative) are clearly much higher than those of mislabeling a benign one (false positive). To overcome this drawback and further improving the classification accuracy of the breast cancer diagnosis, in this work, a novel breast cancer intelligent diagnosis approach has been proposed, which employed information gain directed simulated annealing genetic algorithm wrapper (IGSAGAW) for feature selection, in this process, we performs the ranking of features according to IG algorithm, and extracting the top m optimal feature utilized the cost sensitive support vector machine (CSSVM) learning algorithm. Our proposed feature selection approach which can not only help to reduce the complexity of SAGASW algorithm and effectively extracting the optimal feature subset to a certain extent, but it can also obtain the maximum classification accuracy and minimum misclassification cost. The efficacy of our proposed approach is tested on Wisconsin Original Breast Cancer (WBC) and Wisconsin Diagnostic Breast Cancer (WDBC) breast cancer data sets, and the results demonstrate that our proposed hybrid algorithm outperforms other comparison methods. The main objective of this study was to apply our research in real clinical diagnostic system and thereby assist clinical physicians in making correct and effective decisions in the future. Moreover our proposed method could also be applied to other illness diagnosis.     

基于BP神经网络的SVPWM控制系统仿真研究

将SVPWM控制方法应用于控制系统的三相逆变器部分,通过BP神经网络得到SVPWM的调制波信号。在MATLAB/Simulink软件平台上,构建了神经网络仿真模型,在异步电动机控制系统中进行了仿真研究。结果表明基于BP神经网络实现SVPWM控制信号的正确性和可行性。     

论体验式教育在思想政治理论课程中的作用

体验式教育具有传统教育所不具备的优势,对于思想政治理论课程的开展具有建设性的功能,它能够提供新的模式,促进大学生综合能力的全面发展,如指导学生优化人际关系、促进学生个性的全面发展等。