检索结果-南通市图书馆

Target-enclosing affine formation control of two-layer networked spacecraft with collision avoidance

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 Aeronautics 2019年第12期32卷 2679-2693页

作者： Yang XU delin LUO Dongyu LI Yancheng YOU Haibin DUAN School of Aerospace Engineering Xiamen UniversityXiamen 361005China Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100083China Department of Electrical&Computer Engineering National University of SingaporeSingapore 117583Singapore

This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in this paper is generally directed, which is suitable for practical space missions. Firstly, distributed finite-time sliding-mode estimators and formation controllers in both layers are designed separately to improve the flexibility of the formation control system. By introducing the properties of affine transformation into formation control protocol design,the controllers can be used to track different time-varying target formation patterns. Besides, multilayer time-varying encirclements can be achieved with particular shapes to surround the moving target. In the sequel, by integrating adaptive neural networks and specialized artificial potential functions into backstepping controllers, the problems of uncertain Euler-Lagrange models, collision avoidance as well as formation reconfiguration are solved simultaneously. The stability of the proposed controllers is verified by the Lyapunov direct method. Finally, two simulation examples of triangle formation and more complex hexagon formation are presented to illustrate the feasibility of the theoretical results.

关键词： Affine formation control Collision avoidance Lyapunov stability Target enclosing Two-layer strategy

Pulp health and calcific healing of a complicated crown–root fracture with additional root fracture in a maxillary incisor: A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2025年第3期13卷 42-49页

作者： Na Li Yue-Yue Ren Ying Tang Qi Yang Tian-Tian meng Song Li Jing Zhang Stomatological Hospital and College Anhui Medical UniversityHefei 230032Anhui ProvinceChina Department of Endodontics The Affiliated Stomatological Hospital of Xuzhou Medical UniversityXuzhou 221000Jiangsu ProvinceChina

BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in *** SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical *** the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival ***-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival *** This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.

关键词： Complicated crown-root fracture Multiple root fracture Spontaneous healing Cone-beam computed tomography Long-term follow-up Case report

Structural analysis and anti-complement activity of polysaccharides extracted from Grateloupia livida (Harv.) Yamada

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

Journal of Oceanology and Limnology 2019年第3期37卷 806-814,I0001-I0002页

作者： ZHANG Wenjing JIN Weihua DUAN delin ZHANG Quanbin Key Laboratory of Experimental Marine Biology Institute of OceanologyChinese Academy of SciencesQingdao 266071China School of Medicine Zhejiang UniversityHangzhou 310058China College of Biotechnology and Bioengineering Zhejiang University of TechnologyHangzhou 310014China Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China State Key Lab of Seaweed Bioactive Substances Qingdao 266000China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Polysaccharides were extracted from Grateloupia livida(Harv.) Yamada using hot water(extracted product denoted WGW) and then degraded in dilute sulfuric acid(degraded product denoted WGWD). The degraded mixture was then separated into four fractions through anion exchange chromatography on 2-diethylaminoethanol(DEAE)-Bio-Gel Agarose FF gel. Electrospray ionization collision-induced dissociation tandem mass spectrometry(ESI-CID-MS/MS) was performed to elucidate the structural features of all fractions. In combination with nuclear magnetic resonance spectroscopy(NMR)and infrared spectroscopy(IR) data, the major polysaccharide structures were concluded to be μ-carrageenan and κ-carrageenan. μ-Carrageenan usually has a backbone of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-6, while κ-carrageenan consists of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-3,6-anhydrogalactopyranose residues. Trace v-carrageenan, composed of 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-2 and C-6, was also detected. Furthermore, the polysaccharide had a backbone comprising 1,3-linked β-D-galactopyranose and1,4-linked α-L-galactopyranose sulfated at C-6, which is the agarose precursor. The hydroxy groups in the galactopyranose were partially substituted by methyl and pyruvic acid acetal(PA) groups. The anticomplementary activities of WGW and its derivatives against classical pathways were measured. The native polysaccharides in WGW had higher activities, while the derivatives had much weaker activities. This indicated that the molecular weight and sulfate content were important factors affecting the anti-complement activity.

关键词： red alga Grateloupia livida(Harv.)Yamada mass spectrometry structure

Hierarchical protection control system of smart substations

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2014年第3期2卷 282-288页

作者： Yuping ZHENG delin WANG Zexin ZHOU Tuanjie CAO NARI Group Corporation Nanjing 211106China National Electric Power Dispatching Control Center Beijing 100031China China Electric Power Research Institute Beijing 100192China

This paper analyzes the problems of the relay protections and secondary circuits of traditional substations,and introduces the hierarchical protection and control system of smart substations based on the technologies like IEC 61850 Standard,electronic instrument transformer,process level network,and wide area optical fiber communication network,*** hierarchical protection and control system includes three levels:local area protection,substation area protection and control,and wide area protection and *** three levels are combined to solve the problems of the relay protections in traditional substations,thus improving protection performance and control capability of the system.

关键词： Smart substation Relay protection Hierarchical protection and control system Local area protection Substation area protection and control Wide area protection and control

内卷感知对大学生积极心理健康的影响:一项短期追踪研究

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

黑龙江高教研究 2025年第2期43卷 115-123页

作者：周昱昊张萌中国人民公安大学北京100038

采用问卷调查法,通过5个月两阶段的纵向追踪探讨了627名中国大学生内卷感知对其积极心理健康的影响以及内在机制和边界条件。研究结果表明,内卷感知负向预测大学生的积极心理健康,自我调节疲劳在内卷感知和积极心理健康之间起中介作用,... 详细信息

采用问卷调查法,通过5个月两阶段的纵向追踪探讨了627名中国大学生内卷感知对其积极心理健康的影响以及内在机制和边界条件。研究结果表明,内卷感知负向预测大学生的积极心理健康,自我调节疲劳在内卷感知和积极心理健康之间起中介作用,且自我调节疲劳和积极心理健康存在相互预测作用;自我概念清晰性调节了内卷感知对自我调节疲劳和积极心理健康的作用。为高等教育内卷现象中大学生心理健康的干预提供了理论依据,强调了大学生群体积极应对内卷压力、发展清晰的自我概念和保护自我调节资源的重要性。

关键词：大学生内卷感知自我调节疲劳积极心理健康自我概念清晰性

在线全文

学校读者我要写书评

暂无评论

Guest editorial

International Journal of Intelligent Computing and Cybernetics 2017年第4期10卷 410-411页

作者： delin Luo Feng Lin Department of Automation Xiamen UniversityXiamenChina Temasek Laboratories National University of SingaporeSingapore

Autonomous control of Unmanned Aerial System(UAS)is that UASs can make decisions in the flight and carry out missions autonomously according to the scheduled tasks and rules through online sensing the surrounding *** cooperation,UASs can share information among individual agents and work together to accomplish complicated mission which would not be possible for a single agent *** the development of UAS technology,autonomous control has become one of the hot topics and key technologies in UAS research field.

关键词： agent individual autonomous

基于Transformer模型的时序数据预测方法综述

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

计算机科学与探索 2025年第1期19卷 45-64页

作者：孟祥福石皓源辽宁工程技术大学电子与信息工程学院辽宁葫芦岛125105

时序数据预测(TSF)是指通过分析历史数据的趋势性、季节性等潜在信息,预测未来时间点或时间段的数值和趋势。时序数据由传感器生成,在金融、医疗、能源、交通、气象等众多领域都发挥着重要作用。随着物联网传感器的发展,海量的时序数据... 详细信息

时序数据预测(TSF)是指通过分析历史数据的趋势性、季节性等潜在信息,预测未来时间点或时间段的数值和趋势。时序数据由传感器生成,在金融、医疗、能源、交通、气象等众多领域都发挥着重要作用。随着物联网传感器的发展,海量的时序数据难以使用传统的机器学习解决,而Transformer在自然语言处理和计算机视觉等领域的诸多任务表现优秀,学者们利用Transformer模型有效捕获长期依赖关系,使得时序数据预测任务取得了飞速发展。综述了基于Transformer模型的时序数据预测方法,按时间梳理了时序数据预测的发展进程,系统介绍了时序数据预处理过程和方法,介绍了常用的时序预测评价指标和数据集。以算法框架为研究内容系统阐述了基于Transformer的各类模型在TSF任务中的应用方法和工作原理。通过实验对比了各个模型的性能、优点和局限性,并对实验结果展开了分析与讨论。结合Transformer模型在时序数据预测任务中现有工作存在的挑战提出了该方向未来发展趋势。

关键词：深度学习时序数据预测数据预处理 Transformer模型

Preparation and characterization of agar, agarose,and agaropectin from the red alga Ahnfeltia plicata

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2019年第3期37卷 815-824页

作者： ZHANG Yu FU Xiaoting DUAN delin XU Jiachao GAO Xin College of Food Science and Engineering Ocean University of ChinaQingdao 266003China Key Laboratory of Experimental Marine Biology Institute of OceanologyChinese Academy of SciencesQingdao 266071China State Key Lab of Seaweed Bioactive Substances Qingdao 266400China

Agar,agarose,and agaropectin were extracted from the red alga Ahnfeltia plicata,and their properties and structures were *** was extracted by a comparatively low alkaline consumption of 1.2%.It exhibited a gel strength of 1 152.50±74.25 g/cm^2 and a sulfate content of 0.55%±0.08%.The yield of agar from *** was 24.53%,which is higher than those of other agarophytes commonly used in *** kinds of the method were compared for the purification of agarose,and the physicochemical properties of agarose that was prepared under the optimal condition were identical to those of commercially available ***,agaropectin was purified from *** and characterized by GC,HPLC,UV-spectrum,and FI-IR to understand its composition and *** was the first time to comprehensively study the agar and its fractions from the red alga of *** research provided an eco-friendly agar extraction method from *** and revealed its potential application for the production of agar,agarose,and agaropectin.

关键词： Ahnfeltia plicata agar agarose agaropectin

New advances in multiple autonomous aerial robots formation control technology

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2019年第10期62卷 1871-1872页

作者： XU Yang LUO delin YOU YanCheng DUAN HaiBin School of Aerospace Engineering Xiamen UniversityXiamen361102China School of Automation Science and Electrical Engineering Beihang UniversityBeijing100191China

Autonomous aerial robotics has become a hot direction ofresearch inside the community of robotics and control. Theprimary problem addressed by formation control is to steermultiple aerial robots to form desired geometric patterns and,at the same time, realize desired collective swarming behaviorsin a decentralized or distributed manner. In contrast toground vehicles, aerial robots have the ability to work inthree-dimensional (3D) airspace. Equipped with electric orhydraulic motors, the vertical take-off and landing (VTOL)capability is a typical performance of aerial robots. Formationcontrol technology for such aerial robots is incessantlyspringing up to satisfy the requirements of highly intelligentautonomous systems, which affects both military and civilareas, including missile defense, battlefield surveillance,satellite network construction, fire suppression, power gridinspection, commercial show, etc. [1–5]. Such a problem ofmultiple aerial robots formation control is exceptionallychallenging to analyze if practical constraints such as complexdynamics, motion constraints, and imperfect measurementsare incorporated.

关键词： Laplacian New advances in multiple autonomous aerial robots formation control technology