检索结果-南通市图书馆

State Estimation of Drive-by-Wire Chassis Vehicle Based on Dual Unscented Particle Filter Algorithm

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第1期37卷 99-113页

作者： zixu wang Chaoning Chen Quan Jiang Hongyu Zheng Chuyo Kaku State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130022China Jiangsu Chaoli Electric Co.Ltd. Zhenjiang 212321China

Accurate vehicle dynamic information plays an important role in vehicle driving ***,due to the characteristics of high mobility and multiple controllable degrees of freedom of drive-by-wire chassis vehicles,the current mature application of traditional vehicle state estimation algorithms can not meet the requirements of drive-by-wire chassis vehicle state *** paper proposes a state estimation method for drive-by-wire chassis vehicle based on the dual unscented particle filter algorithm,which make full use of the known advantages of the four-wheel drive torque and steer angle parameters of the drive-by-wire chassis *** the dual unscented particle filter algorithm,two unscented particle filter transfer information to each other,observe the vehicle state information and the tire force parameter information of the four wheels respectively,which reduce the influence of parameter uncertainty and model parameter changes on the estimation accuracy during *** performance with the dual unscented particle filter algorithm,which is analyzed in terms of the time-average square error,is superior of the unscented Kalman filter *** effectiveness of the algorithm is further verified by driving simulator *** this paper,a vehicle state estimator based on dual unscented particle filter algorithm was proposed for the first time to improve the estimation accuracy of vehicle parameters and states.

关键词： Drive-by-wire chassis vehicle Vehicle state estimation Dual unscented particle filter Tire force estimation Unscented particle filter

Representation of the Stratospheric Circulation in CRA-40 Reanalysis:The Arctic Polar Vortex and the Quasi-Biennial Oscillation

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第5期41卷 894-914页

作者： zixu wang Shirui YAN Jinggao HU Jiechun DENG Rongcai REN Jian RAO Key Laboratory of Meteorological Disaster Ministry of Education(KLME)Joint International Research Laboratory of Climate and Environment Change(ILCEC)Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The representation of the Arctic stratospheric circulation and the quasi-biennial oscillation(QBO)during the period 1981–2019 in a 40-yr Chinese global reanalysis dataset(CRA-40)is evaluated by comparing two widely used reanalysis datasets,ERA-5 and ***-40 demonstrates a comparable performance with ERA-5 and MERRA-2 in characterizing the winter and spring circulation in the lower and middle Arctic ***,differences in the climatological polar-mean temperature and polar night jet among the three reanalyses are within±0.5 K and±0.5 m s^(–1),*** onset dates of the stratospheric sudden warming and stratospheric final warming events at 10 hPa in CRA-40,together with the dynamics and circulation anomalies during the onset process of warming events,are nearly identical to the other two reanalyses with slight *** contrast,the CRA-40 dataset demonstrates a deteriorated performance in describing the QBO below 10 hPa compared to the other two reanalysis products,manifested by the larger easterly biases of the QBO index,the remarkably weaker amplitude of the QBO,and the weaker wavelet power of the QBO *** pronounced biases are mainly concentrated in the period 1981–98 and largely reduced by at least 39%in 1999–***,particular caution is needed in studying the QBO based on *** three reanalyses exhibit greater disagreement in the upper stratosphere compared to the lower and middle stratosphere for both the polar region and the tropics.

关键词： CRA-40 ERA-5 MERRA-2 Arctic stratosphere the QBO

Time series models in prediction of severe fever with thrombocytopenia syndrome cases in Shandong province,China

在线全文

学校读者我要写书评

暂无评论

Infectious Disease Modelling 2024年第1期9卷 224-233页

作者： zixu wang Wenyi Zhang Ting Wu Nianhong Lu Junyu He Junhu wang Jixian Rao Yuan Gu Xianxian Cheng Yuexi Li Yong Qi Pest Control Department Huadong Research Institute for Medicine and BiotechniquesNanjingJiangsu province210002China Bengbu Medical College BengbuAnhui province233030China Chinese PLA Center for Disease Control and Prevention Beijing100071China Jinling Hospital Medical School of Nanjing UniversityNanjingJiangsu province210002China Ocean College Zhejiang UniversityZhoushan316021China Ocean Academy Zhejiang UniversityZhoushan316021China

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by the SFTS virus (SFTSV). Predicting the incidence of this disease in advance is crucial for policymakers to develop prevention and control strategies. In this study, we utilized historical incidence data of SFTS (2013–2020) in Shandong Province, China to establish three univariate prediction models based on two time-series forecasting algorithms Autoregressive Integrated Moving Average (ARIMA) and Prophet, as well as a special type of recurrent neural network Long Short-Term Memory (LSTM) algorithm. We then evaluated and compared the performance of these models. All three models demonstrated good predictive capabilities for SFTS cases, with the predicted results closely aligning with the actual cases. Among the models, the LSTM model exhibited the best fitting and prediction performance. It achieved the lowest values for mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE). The number of SFTS cases in the subsequent 5 years in this area were also generated using this model. The LSTM model, being simple and practical, provides valuable information and data for assessing the potential risk of SFTS in advance. This information is crucial for the development of early warning systems and the formulation of effective prevention and control measures for SFTS.

关键词： Severe fever with thrombocytopenia syndrome Long short-term memory Prediction model Autoregressive integrated moving average Prophet

Development and Comparison of Time Series Models in Predicting Severe Fever with Thrombocytopenia Syndrome Cases—Hubei Province,China,2013-2020

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China CDC weekly 2024年第37期6卷 962-967,I0011-I0014页

作者： zixu wang Jinwei Zhang Wenyi Zhang Nianhong Lu Qiong Chen Junhu wang Yingqing Mao Haiming Yi Yixin Ge Hongming wang Chao Chen Wei Guo Xin Qi Yuexi Li Ming Yue Yong Qi Huadong Research Institute for Medicine and Biotechniques Nanjing CityJiangsu ProvinceChina Bengbu Medical College Bengbu CityAnhui ProvinceChina Department of Anesthesiology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing CityJiangsu ProvinceChina Chinese PLA Center for Disease Control and Prevention BeijingChina The Second People’s Hospital of Yiyuan County Zibo CityShandong ProvinceChina Department of Infectious Diseases The First Affiliated Hospital of Nanjing Medical UniversityNanjing CityJiangsu ProvinceChina School of Public Health Nanjing Medical UniversityNanjing CityJiangsu ProvinceChina&Joint first authors.

Introduction:Severe fever with thrombocytopenia syndrome(SFTS)is an emerging infectious disease caused by the SFTS virus,which has a high mortality *** the number of SFTS cases is essential for early outbreak warning and can offer valuable insights for establishing prevention and control ***:In this study,data on monthly SFTS cases in Hubei Province,China,from 2013 to 2020 were *** time series models based on seasonal auto-regressive integrated moving average(SARIMA),Prophet,eXtreme Gradient Boosting(XGBoost),and long short-term memory(LSTM)were developed using these historical data to predict SFTS *** established models were evaluated and compared using mean absolute error(MAE)and root mean squared error(RMSE).Results:Four models were developed and performed well in predicting the trend of SFTS *** XGBoost model outperformed the others,yielding the closest fit to the actual case numbers and exhibiting the smallest MAE(2.54)and RMSE(2.89)in capturing the seasonal trend and predicting the monthly number of SFTS cases in Hubei ***:The developed XGBoost model represents a promising and valuable tool for SFTS prediction and early warning in Hubei Province,China.

关键词： Hubei prevention establishing

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于端壁L形凹槽的扩压叶栅角区分离控制

航空学报 2024年第10期45卷 82-110页

作者：王博吴艳辉黄令举王子胥西北工业大学动力与能源学院西安710129 陕西省航空发动机内流动力学重点实验室西安710129

为了解决用于控制压气机角区分离的旋涡发生器技术存在的不足,以高速扩压叶栅为研究对象,深入探究了利用端壁L形凹槽结构产生的流向涡抑制压气机角区分离的流动控制策略。首先,通过引入标准造型空间和函数叠合思想,为端壁L形凹槽结构发... 详细信息

为了解决用于控制压气机角区分离的旋涡发生器技术存在的不足,以高速扩压叶栅为研究对象,深入探究了利用端壁L形凹槽结构产生的流向涡抑制压气机角区分离的流动控制策略。首先,通过引入标准造型空间和函数叠合思想,为端壁L形凹槽结构发展了一种便捷且通用的参数化建模方法,并基于该方法开展了端壁L形凹槽的优化设计。通过比较原型叶栅和最优方案的流场仿真结果发现:端壁L形凹槽可以通过其产生的槽道分离涡来有效阻挡横向二次流,切断端壁低能流体向角区的供应,从而显著缓解角区反流、阻止角区分离伴生旋涡的形成,能够在宽广的攻角范围内显著改善叶栅的气动性能。对比不同Pareto最优方案的计算结果发现:槽道分离涡的旋涡强度决定了凹槽对横向二次流的控制效果以及引入附加流动损失和堵塞效应的严重程度,这是影响流动控制效果的关键因素。然后,将基于Sobol指标法的灵敏度分析方法与控制变量法相结合分析了设计参数对端壁L形凹槽流动控制效果的影响。结果表明:凹槽切向位置、凹槽深度、上游凹槽宽度和上游凹槽长度对凹槽的流动控制效果影响较为显著;其中凹槽切向位置主要影响槽道分离涡距离吸力面角区的远近,而后三者则主要影响槽道分离涡的旋涡强度。最后,基于以上分析,总结了端壁L形凹槽的设计参数选取原则。

关键词：扩压叶栅角区分离端壁L形凹槽槽道分离涡设计参数

在线全文

学校读者我要写书评

暂无评论

说作业教研的内涵意蕴与结构探析

天津师范大学学报（基础教育版） 2024年第4期25卷 54-58页

作者：吴立宝王子续天津师范大学教育学部北京师范大学数学科学学院北京100875

随着“双减”政策的颁布,中小学作业正进行着重大改革,目标在于达到减负提质的效果。作业是连接课程、教学、学习和评价的关键环节,以作业为载体,以“说”为外化路径,以提升作业教学质量为目的,提出一种新型教研形式——说作业。研究认... 详细信息

随着“双减”政策的颁布,中小学作业正进行着重大改革,目标在于达到减负提质的效果。作业是连接课程、教学、学习和评价的关键环节,以作业为载体,以“说”为外化路径,以提升作业教学质量为目的,提出一种新型教研形式——说作业。研究认为,说作业结构框架包括说作业理念、说作业设计、说作业批改、说作业评讲、说作业反思,以语言为媒介展现作业教学全过程,在诊断、研讨、改进的过程中,可促使作业教学更加精细化、深入化、完备化,发挥说作业的理论价值与应用价值。

关键词：说作业 “双减”政策减负提质

在线全文

学校读者我要写书评

暂无评论

共轴刚性旋翼高速直升机配平策略优化设计

航空学报 2024年第9期45卷 254-271页

作者：王梓旭李攀鲁可朱振华陈仁良南京航空航天大学直升机动力学全国重点实验室南京210016 中国直升机设计研究所景德镇333001

最大巡航速度、最大平飞速度是共轴刚性旋翼高速直升机最重要的性能指标之一,其特殊的构型和工作方式导致其旋翼桨毂载荷问题突出。高速飞行俯仰姿态角、平尾安装角、横向周期变距差动、旋翼转速等配平状态和设计参数对需用功率、桨毂... 详细信息

最大巡航速度、最大平飞速度是共轴刚性旋翼高速直升机最重要的性能指标之一,其特殊的构型和工作方式导致其旋翼桨毂载荷问题突出。高速飞行俯仰姿态角、平尾安装角、横向周期变距差动、旋翼转速等配平状态和设计参数对需用功率、桨毂载荷、操稳特性等具有显著的非线性交叉耦合影响,在考虑飞行品质相关要求下开展了高速飞行配平策略优化设计方法研究,为获得飞行性能和桨毂载荷综合最优配平策略提供设计手段。基于共轴刚性旋翼高速直升机非线性飞行动力学模型,分析了不同配平策略设计参数对配平特性、稳定性、操纵性等影响规律;在此基础上,将配平策略设计问题描述为数学优化问题;为提高优化计算效率和降低优化失败风险,基于Kriging代理模型开展配平策略优化设计研究。优化结果表明:在最大巡航速度和最大飞行速度下,相比于基准配平策略,在最优功率配平策略下需用功率分别降低5.7%、6.9%;在最优桨毂力矩配平策略下桨毂力矩载荷分别降低55.6%、55.2%;在需用功率、桨毂力矩综合最优策略下需用功率分别降低1.8%、3.1%,桨毂力矩载荷分别降低49.4%、46.2%,验证了提出的配平策略优化设计方法的有效性。

关键词：共轴刚性旋翼高速直升机配平特性配平策略 Kriging模型优化设计

在线全文

学校读者我要写书评

暂无评论

离心式压缩机负荷控制与喘振控制探讨

当代化工研究 2024年第15期 114-116页

作者：王梓旭中石油吉林化工工程有限公司吉林132002

离心式压缩机是石油化工的重要设备,针对离心式压缩机自身结构特点,总结了离心式压缩机负荷控制的四种方式及优缺点。同时对防喘振控制的注意事项进行了详细的描述,并在传统控制的基础上提出超驰控制、负荷跟踪控制等优化控制措施。优... 详细信息

离心式压缩机是石油化工的重要设备,针对离心式压缩机自身结构特点,总结了离心式压缩机负荷控制的四种方式及优缺点。同时对防喘振控制的注意事项进行了详细的描述,并在传统控制的基础上提出超驰控制、负荷跟踪控制等优化控制措施。优化控制既可以保证离心式压缩机的安全稳定运行,又可以降低压缩机能耗,为今后离心式压缩机控制系统的设计提供了参考。

关键词：离心式压缩机负荷控制防喘振控制导叶调节

单向陶瓷基复合材料C/SiC变角度顺逆磨的对比试验

在线全文

学校读者我要写书评

暂无评论

中国机械工程 2024年第2期35卷 235-243页

作者：张立峰王梓旭张旺通邓云飞隋翯郭志永中国民航大学航空工程学院天津300300

通过正十二边形磨削轨迹测试方法研究了单向C/SiC的磨削力和加工表面质量的影响机制。研究发现,相较于顺磨,逆磨的切向磨削力减小10%~25%,法向磨削力减小30%~50%,表面粗糙度减小25%~65%;纤维磨削角对磨削特性具有显著影响,顺纤维磨削时... 详细信息

通过正十二边形磨削轨迹测试方法研究了单向C/SiC的磨削力和加工表面质量的影响机制。研究发现,相较于顺磨,逆磨的切向磨削力减小10%~25%,法向磨削力减小30%~50%,表面粗糙度减小25%~65%;纤维磨削角对磨削特性具有显著影响,顺纤维磨削时,磨削力由大到小的纤维磨削角排序为60°、30°、90°、0°,逆纤维磨削时的排序为120°、90°、150°、180°;加工表面粗糙度Sa由大到小的纤维磨削角排序为0°、150°、120°、30°、60°、90°;C/SiC磨削加工时,材料的变形回弹效应较明显。对比了不同纤维磨削角下的表面微观形貌,提出了磨削材料去除模型。

关键词：复合材料磨削角度顺/逆磨材料去除模型