检索结果-南通市图书馆

Control Theory and Technology 2024年第1期22卷 69-80页

作者： junqi yang Jianhao Xie Feiyang Liu School of Electrical Engineering and Automation Henan Key Laboratory of Intelligent Detection and Control of Coal Mine EquipmentHenan Polytechnic UniversityJiaozuo454003HenanChina

For a class of time-delay discrete-time linear systems with external disturbance and measurement noise, the interval estimation problems of state and measurement noise are investigated in this paper. First, the system state together with the time-delay term and measurement noise is augmented as a new state, and a singular system is then constructed. Subsequently, a kind of decoupling technique is employed to eliminate the effect of external disturbance, and an observer is designed to simultaneously estimate the system state and measurement noise. Based on the estimated state and measurement noise, the interval estimations of system state and measurement noise are obtained by reachability analysis technique. Finally, the effectiveness of the proposed method is verified by a four-tank liquid level system.

关键词： Interval estimation Time-delay system Observer design Reachability analysis

斯氏体系中的符号化建制——析“单位与任务”中的动作观点

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

新疆艺术学院学报 2024年第3期22卷 21-27页

作者：杨竣淇中央戏剧学院北京100710

“单位与任务”是斯坦尼斯拉夫斯基演剧理论体系中的一组重要元素概念,它不仅是一种对进入与把握斯氏演剧理论体系具有指导性意义的操作方法,更重要的是,“单位与任务”已经是一组从根本上触及戏剧基础理论的重要概念。斯氏盯准作为戏... 详细信息

“单位与任务”是斯坦尼斯拉夫斯基演剧理论体系中的一组重要元素概念,它不仅是一种对进入与把握斯氏演剧理论体系具有指导性意义的操作方法,更重要的是,“单位与任务”已经是一组从根本上触及戏剧基础理论的重要概念。斯氏盯准作为戏剧表现手段的动作来确定“单位与任务”的实质与关系,视动作为符号而来对戏剧的表意功能予以剖判,将以往直接从“所指”(结构、情节、主题)入手转化为以“能指”(动作)进入而通达“所指”。

关键词： “单位与任务” 动作斯坦尼斯拉夫斯基演剧体系戏剧动作二重性

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

钻柱振动的主被动控制研究进展与展望

天然气工业 2024年第6期44卷 98-110页

作者：李欣业高赫远郭晓强张文学阳君奇杨杰河北工业大学机械工程学院中国石油塔里木油田公司河北瑞兆激光机电工程有限公司

在油气井钻进作业过程中,钻柱长期工作在充满钻井液的狭长井筒里,其受到井底压力、摩擦、岩石硬度变化的影响,受力情况非常复杂,会产生多种形式的振动,这些是影响钻具寿命和钻进效率的最主要因素。为系统分析工程界和学术界长期以来普... 详细信息

在油气井钻进作业过程中,钻柱长期工作在充满钻井液的狭长井筒里,其受到井底压力、摩擦、岩石硬度变化的影响,受力情况非常复杂,会产生多种形式的振动,这些是影响钻具寿命和钻进效率的最主要因素。为系统分析工程界和学术界长期以来普遍关注的钻柱系统振动的有效控制问题,对近几十年来国内外在钻杆振动控制上使用的各种方法进行了分类和归纳,总结了各种方法的特点、应用场景以及不足之处,并对钻柱系统振动控制技术的发展趋势进行了展望。研究结果表明:(1)现有的钻柱振动主动控制主要集中于单一方向(扭转振动)和2个方向的耦联振动(纵扭耦联振动),且控制参数主要集中于钻压和扭矩,仅控制单方向的振动和单参数的调节,效果将很难保证;(2)被动控制是通过改变钻柱系统自身的结构或设计参数来抑制其振动,控制过程不受结构响应和外部干扰的影响,虽然效果有较大的局限性,但仍应在设计阶段给与足够的重视;(3)今后钻柱振动控制将朝着同时基于地面和井下测量数据,纵、横、扭3个方向联合控制的方向发展。结论认为,钻杆振动往往是几种基本振动形式的耦联,并具有明显的非线性特征,基于数据驱动的钻进系统动力学建模、考虑模型不确定性的现代鲁棒自适应控制技术以及新兴的人工智能技术将会成为未来钻柱振动研究和发展的主流趋势。

关键词：钻杆耦联振动主动控制被动控制智能控制数字驱动建模随钻测量

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

低帮篮球鞋的设计演变与趋势

西部皮革 2024年第12期46卷 66-68页

作者：杨钧淇四川文理学院

通过文献梳理和案例分析，文章探讨了低帮篮球鞋的起源、设计、发展趋势及个性化定制。设计上，低帮篮球鞋需平衡弹性和支撑，采用高弹性材料提供反弹性和能量回馈，并加固关键部位以增强稳定性。透气性也是设计重点。未来发展方向侧重... 详细信息

通过文献梳理和案例分析，文章探讨了低帮篮球鞋的起源、设计、发展趋势及个性化定制。设计上，低帮篮球鞋需平衡弹性和支撑，采用高弹性材料提供反弹性和能量回馈，并加固关键部位以增强稳定性。透气性也是设计重点。未来发展方向侧重于材料创新和个性化定制，满足消费者对性能、舒适度和独特性的追求。

关键词：球鞋设计材料创新运动表现

基于相位校正的分布式光纤大探测孔径多维定位

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

中国激光 2024年第8期51卷 206-213页

作者：杨竣淇王照勇刘依凡帅禄玮高侃叶青蔡海文中国科学院上海光学精密机械研究所空间激光传输与探测技术重点实验室上海201800 中国科学院大学材料与光电研究中心北京100049 上海中科神光光电产业有限公司上海201815 上海佘山地球物理国家野外科学观测研究站上海201602

分布式光纤多维定位对于周界安防、地震速报、目标跟踪等应用有着十分重要的意义。地震源或空气中声源波长与光纤探测孔径为同一量级,光纤传感通道无法对波场进行密集采样,难以实现精准定位。为了消除光纤大探测孔径对目标源多维定位的... 详细信息

分布式光纤多维定位对于周界安防、地震速报、目标跟踪等应用有着十分重要的意义。地震源或空气中声源波长与光纤探测孔径为同一量级,光纤传感通道无法对波场进行密集采样,难以实现精准定位。为了消除光纤大探测孔径对目标源多维定位的影响,提出了一种基于相位校正的分布式光纤大探测孔径多维定位方法。首先建立了光纤传感通道对目标源的响应模型,分析了光纤阵列相位误差来源,根据目标源预估计位置对光纤阵列采样信号进行相位校正;然后对校正后的信号进行空间谱估计并采用多次迭代降低定位误差。现场初步实验结果表明,所提方法能够有效实现对目标源的二维定位,定位结果与实际测量位置的误差为1.1 m。该方法可用于既有光缆,提高了分布式光纤传感系统在实际应用中的定位能力。

关键词：光纤光学分布式声波传感阵列信号处理目标定位

同方期刊数据库

基于电力大数据的钢铁企业大气污染物排放核算模型构建及应用

在线全文

学校读者我要写书评

暂无评论

环境科学研究 2024年第2期37卷 299-307页

作者：周卫青杨俊琦宁亮吴华成薄宇张强田贺忠国网冀北电力有限公司电力科学研究院华北电力科学研究院有限责任公司北京100045 北京师范大学环境学院环境模拟与污染控制国家重点联合实验室北京100875 北京师范大学大气环境研究中心北京100875 国网冀北电力有限公司唐山供电公司河北唐山063000 清华大学地球系统科学系北京100084

近年来,各级生态环境部门与国家电网公司积极签署战略合作协议,促进电力大数据在生态环境管理信息化平台的应用.本研究通过梳理电力大数据在大气污染防治中的应用,以唐山市钢铁行业为例构建基于电力大数据的大气污染物高时间精度排放核... 详细信息

近年来,各级生态环境部门与国家电网公司积极签署战略合作协议,促进电力大数据在生态环境管理信息化平台的应用.本研究通过梳理电力大数据在大气污染防治中的应用,以唐山市钢铁行业为例构建基于电力大数据的大气污染物高时间精度排放核算模型,进一步挖掘电力大数据在大气污染排放控制中的应用潜力.结果表明:①模型核算的2019年唐山市17家钢铁企业的大气污染物排放量与2019年唐山市大气污染物排放清单(简称“城市清单”)结果一致性较好,SO_(2)、NOx和PM_(2.5)排放量分别为1017.90、2047.75、1141.81t,误差介于-0.46%~4.27%之间.②基于工序而言,以PM_(2.5)为例,模型预测结果与城市清单结果的相对误差在-17.34%~10.60%之间.③唐山某钢铁企业2022年SO_(2)、NOx、PM_(2.5)月排放量受钢铁市场价格影响较大,1月和6月分别为最高和最低污染物排放月,而其日排放受行业特征影响较为平稳,小时排放可能受电价波动影响较大.研究显示,基于电力大数据的大气污染物核算模型阐明了电力大数据和污染排放的动态响应关系,一定程度上提升了排放核算的时间精细度,实证了基于电力大数据核算大气污染物排放的研究意义和可行性.

关键词：电力大数据应用现状大气污染物排放核算模型高时间精度

Observer-based robust control for a class of sampled-data systems with model uncertainty and external disturbance

在线全文

学校读者我要写书评

暂无评论

Journal of Control and Decision 2023年第3期10卷 454-463页

作者： junqi yang Zechen Li Yantao Chen School of Engineering and Automation Henan Polytechnic UniversityJiaozuoPeople’s Republic of China Henan Key Laboratory of Intelligent Detection and Control of Coal Mine Equipment Henan Polytechnic UniversityJiaozuoPeople’s Republic of China

This paper studies the issue of observer-based feedback stabilisation for a class of linear sampleddatasystems with model uncertainty and external disturbance. First, for a sampled-data systemwith external disturbance, a sampled-data observer is designed to estimate the system ***, a robust H∞ controller based on the observer is developed. For a continuous samplinginterval, the gain matrices of both observer and controller change exponentially. Second,using the state coordinate transformations with an exponential rate, a unified dynamics is constructedby augmenting the state estimation error and the closed-loop system state as a newstate. Next, the sufficient conditions ensuring the asymptotical stability of the closed-loop systemare given by the Lyapunov–Krasovskii method and linear matrix inequality (LMI) ***, the effectiveness of the proposed method is verified by a helicopter model.

关键词： Sampled-data system observer linear matrix inequality robust controller

Grape leaf disease detection based on attention mechanisms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2022年第5期15卷 205-212页

作者： Wenjuan Guo Quan Feng Xiangzhou Li Sen yang junqi yang College of Mechanical and Electrical Engineering Gansu Agricultural UniversityLanzhou 730070China School of Cyber Security Gansu University of Political Science and LawLanzhou 730070China

Prevention and control of grape diseases is the key measure to ensure grape *** order to improve the precision of grape leaf disease detection,in this study,Squeeze-and-Excitation Networks(SE),Efficient Channel Attention(ECA),and Convolutional Block Attention Module(CBAM)attention mechanisms were introduced into Faster Region-based Convolutional Neural Networks(R-CNN),YOLOx,and single shot multibox detector(SSD),to enhance important features and weaken unrelated features and ensure the real-time performance of the model in improving its detection *** study showed that Faster R-CNN,YOLOx,and SSD models based on different attention mechanisms effectively enhanced the detection precision and operation speed of the models by slightly enhancing *** models among the three types of models were selected for comparison,and results showed that Faster R-CNN+SE had lower detection precision,YOLOx+ECA required the least parameters with the highest detection precision,and SSD+SE showed optimal real-time performance with relatively high detection *** study solved the problem of difficulty in grape leaf disease detection and provided a reference for the analysis of grape diseases and symptoms in automated agricultural production.

关键词： disease detection Faster R-CNN YOLOx SSD attention mechanism

Landslide hazard susceptibility evaluation based on SBAS-InSAR technology and SSA-BP neural network algorithm:A case study of Baihetan Reservoir Area

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第3期21卷 952-972页

作者： GUO junqi XI Wenfei yang Zhiquan SHI Zhengtao HUANG Guangcai yang Zhengrong yang Dongqing Faculty of Geography Yunnan Normal UniversityKunming 650500China Key Laboratory of Early Rapid Identification Prevention and Control of Geological Diseases in Traffic Corridor of High Intensity Earthquake Mountainous Area of Yunnan ProvinceKunming 650093China Faculty of Public Safety and Emergency Management Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Geological Disaster Risk Prevention and Control and Emergency Disaster Reduction of Ministry of Emergency Management of the People’s Republic of China Kunming University of Science and TechnologyKunming 650093China Guizhou Geological Survey Institute Guiyang 550081China College of Big Data and Intelligent Engineering Southwest Forestry UniversityKunming 650224China

Landslide hazard susceptibility evaluation takes on critical significance in early warning and disaster prevention and *** order to solve the problems of poor effectiveness of landslide data and complex calculation of weights for multiple evaluation factors in the existing landslide susceptibility evaluation models,in this study,a method of landslide hazard susceptibility evaluation is proposed by combining SBAS-InSAR(Small Baseline Subsets-Interferometric Synthetic Aperture Radar)and SSA-BP(Sparrow Search Algorithm-Back Propagation)neural network *** SBAS-InSAR technology is adopted to identify potential landslide hazards in the study area,update the cataloging data of landslide hazards,and 11 evaluation factors are chosen for constructing the SSA-BP model for training and *** Reservoir area is selected as a case study for *** indicated by the results,the application of SBAS-InSAR technology,combined with both ascending and descending orbit data,effectively addresses the incomplete identification of landslide hazards caused by geometric distortion of single orbit SAR data(e.g.,shadow,overlay,and perspective contraction)in deep canyon areas,thereby enabling the acquisition of up-to-date landslide hazard ***,in comparison to the conventional BP(Back Propagation)algorithm,the accuracy of the model constructed by the SSA-BP algorithm exhibits a significant increase,with mean squared error and mean absolute error reduced by 0.0142 and 0.0607,***,during the process of susceptibility evaluation,the SSA-BP model effectively circumvents the issue of considerable manual interventions in calculating the weight of evaluation *** area under the curve of this model reaches 0.909,surpassing BP(0.835),random forest(0.792),and the information value method(0.699).The risk of landslide occurrence in the Baihetan Reservoir area is positively correlated with slope,surface temperature,and deformation ra

关键词： Baihetan SBAS-InSAR SSA-BP Landslide hazard susceptibility evaluation

Cerium oxide inclusion nucleation mechanism based on classical nucleation theory and two-step nucleation

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第4期42卷 793-802页

作者： Yutang Li Jun Wang Linzhu Wang Chaoyi Chen Shufeng yang junqi Li Xiang Li School of Materials and Metallurgy Guizhou UniversityGuiyang550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Department of Materials&Metallurgy Engineering Guizhou Institute of TechnologyGuiyang550003China

It is challenging to assess the mechanism responsible for the nucleation of inclusions in metals at high *** present work therefore systematically investigates the nucleation of cerium oxide inclusions according to classical nucleation theory and a two-step nucleation *** nucleation rates and nucleation radii of these inclusions are obtained,and the results demonstrate a considerable difference between theoretical and experimental *** the basis of a two-step nucleation mechanism,(CeO_(2))_(n) and(Ce_(2)O_(3))_(n)(n=1-6)clusters were constructed and the thermodynamic properties of both these clusters and of cerium oxide nanoparticles were *** addition,the entropies and heat capacity changes of cerium oxides were determined using first principles calculations and are found to be consistent with literature *** present data indicate that the cerium oxide inclusion nucleation pathway can be summarized as[Ce]+[O]→(CeO_(2))n/(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(2)→core(Ce_(2)O_(3)crystal)-shell((Ce_(2)O_(3))_(2) cluster)nanoparticles→(Ce_(2)O_(3))bulk.

关键词： Cerium oxide inclusion Classical nucleation theory Two-step nucleation mechanism First principles Rare earths