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改进YOLOv7+Bytetrack的小目标检测与追踪 被引量:2
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作者 聂源 赖惠成 高古学 《计算机工程与应用》 CSCD 北大核心 2024年第12期189-202,共14页
近年来,目标检测技术已经相当成熟,但小目标检测一直是目标检测领域的一大挑战。为了解决这一问题,设计一种名为MFF-YOLOv7的小目标检测算法,该算法旨在提高小目标检测的准确率。设计级联双向特征金字塔KBiFPN,以及联合提出的多级感受... 近年来,目标检测技术已经相当成熟,但小目标检测一直是目标检测领域的一大挑战。为了解决这一问题,设计一种名为MFF-YOLOv7的小目标检测算法,该算法旨在提高小目标检测的准确率。设计级联双向特征金字塔KBiFPN,以及联合提出的多级感受野特征聚合模块MFA,来聚合浅层特征并增强特征的信息表达能力。为了解决小目标漏检问题,设计了新的解耦头和新的注意力机制。新的解耦头对小目标的检测能力更强,新的注意力机制可以重点关注感兴趣的小目标区域。引入了一种新的损失函数ECIOU,旨在加快模型的收敛速度。为了验证模型的性能,分别在三个小目标数据集上进行了实验。实验结果表明,MFF-YOLOv7算法提高了检测精度。同时,使用多目标追踪Bytetrack算法在MOT17和VisDrone2019-MOT两个多目标追踪数据集上对新模型进行了验证,进一步证明了其有效性。此外,MFF-YOLOv7算法在动态视频追踪中表现出了良好的性能。 展开更多
关键词 MFF-YOLOv7 小目标检测 多级感受野 多目标追踪 Bytetrack
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Discussion on the Core Strength Training Method for 100-Meter Event in Track and Field Sports
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作者 Jiachen Bian 《Journal of Contemporary Educational Research》 2023年第12期203-208,共6页
In track and field sports,the 100-meter race is an extremely intense sport that requires effective training of athletes’core strength.From the perspective of adolescents,in order to enhance core strength,it is necess... In track and field sports,the 100-meter race is an extremely intense sport that requires effective training of athletes’core strength.From the perspective of adolescents,in order to enhance core strength,it is necessary to effectively fix the pelvic position in the process of exercise,so that the core stability,balance,and coordination of athletes can be improved.The training process of the 100-meter event is mainly an anaerobic metabolic exercise,it is necessary to ensure that athletes maintain a high level of physical readiness during the exercises and concentrate highly on their core strength,so that they can achieve excellent results.This paper analyzes the core strength training for the 100-meter event in track and field sports,discusses its importance,and puts forward specific training methods,hoping to provide guidelines for relevant researchers. 展开更多
关键词 track and field sports 100-meter event Core strength Training methods
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The training process: Planning for strength-power training in track and field. Part 2: Practical and applied aspects 被引量:3
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作者 Brad H. DeWeese Guy Hornsby +1 位作者 Meg Stone Michael H. Stone 《Journal of Sport and Health Science》 SCIE 2015年第4期318-324,共7页
Planning training programs for strength-power track and field athletes require an understanding of both training principles and training theory. The training principles are overload, variation, and specificity. Each o... Planning training programs for strength-power track and field athletes require an understanding of both training principles and training theory. The training principles are overload, variation, and specificity. Each of these principles must be incorporated into an appropriate system of training. Conceptually, periodization embraces training principles and offers advantages in planning, allowing for logical integration and manipulation of training variables such as exercise selection, intensification, and volume factors. The adaptation and progress of the athlete is to a large extent directly related to the ability of the coach/athlete to create and carry an efficient and efficacious training process. This ability includes: an understanding of how exercises affect physiological and performance adaptation (i.e., maximum force, rate of force development, power, etc.), how to optimize transfer of training effect ensuring that training exercises have maximum potential for carryover to performance, and how to implement programs with variations at appropriate levels (macro, meso, and micro) such that fatigue management is enhanced and performance progress is optimized. 展开更多
关键词 Periodization PROGRAMMING Strength training track and field Training process
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The training process: Planning for strength-power training in track and field. Part 1: Theoretical aspects 被引量:3
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作者 Brad H. DeWeese Guy Hornsby +1 位作者 Meg Stone Michael H. Stone 《Journal of Sport and Health Science》 SCIE 2015年第4期308-317,共10页
The process of strength-power training and the subsequent adaptation is a multi-factorial process. These factors range from the genetics and morphological characteristics of the athlete to how a coach selects, orders,... The process of strength-power training and the subsequent adaptation is a multi-factorial process. These factors range from the genetics and morphological characteristics of the athlete to how a coach selects, orders, and doses exercises and loading patterns. Consequently, adaptation from these training factors may largely relate to the mode of delivery, in other words, programming tactics. There is strong evidence that the manner and phases in which training is presented to the athlete can make a profound difference in performance outcome. This discussion deals primarily with block periodization concepts and associated methods of programming for strength-power training within track and field. 2015 Production and hosting by Elsevier B.V. on behalf of Shanghai University of Sport. 展开更多
关键词 Periodization Strength-power training track and field Training process
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Surface current field and seasonal variability in the Kuroshio and adjacent regions derived from satellite-tracked drifter data 被引量:23
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作者 HU Xiaomin XIONG Xuejun +2 位作者 QIAO Fangli GUO Binghuo LIN Xiaopei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2008年第3期11-29,共19页
The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and (1/4) ° latitude by (1/4) ° longitude mean curren... The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and (1/4) ° latitude by (1/4) ° longitude mean currents derived from 323 Argos drifters deployed by Chinese institutions and world ocean circulation experiment from 1979 to 2003. The results show that the Kuroshio surface path adapts well to the western boundary topography and exhibits six great turnings. The branching occurs frequently near anticyclonic turnings rather than near cyclonic ones. In the Luzon Strait, the surface water intrusion into the South China Sea occurs only in fall and winter. The Kuroshio surface path east of Taiwan, China appears nearly as straight lines in summer, fall, and winter, when anticyclonic eddies coexist on its right side; while the path may cyclonically turning in spring when no eddy exists. The Kuroshio intrusion northeast of Taiwan often occurs in fall and winter, but not in summer. The running direction, width and velocity of the middle segment of the Kuroshio surface currents in the East China Sea vary seasonally. The northward intrusion of the Kuroshio surface water southwest of Kyushu occurs in spring and fall, but not in summer. The northmost position of the Kuroshio surface path southwest of Kyushu occurs in fall, but never goes beyond 31 °N. The northward surface current east of the Ryukyu Islands exists only along Okinawa-Amami Islands from spring to fall. In particular, it appears as an arm of an anti- cyclonic eddy in fall. 展开更多
关键词 KUROSHIO surface current field satellite-tracked surface drifter seasonal variability
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Common Sports Injuries and Preventive Measures for Athletes—Take The Track and Field Team Athletes in Yushan County as an Example
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作者 Jieqiong Xie 《教育研究前沿(中英文版)》 2019年第4期313-317,共5页
Taking the common sports injuries and preventive measures of Yushan County middle school track and field athletes as the research object,the sports injuries of Yushan County middle school track and field athletes were... Taking the common sports injuries and preventive measures of Yushan County middle school track and field athletes as the research object,the sports injuries of Yushan County middle school track and field athletes were investigated and analyzed from the angle,type,location and nature of sports injury.Research on sports injury problems,trying to find the causes of sports injuries in daily training of track and field athletes,and proposed targeted preventive measures based on the specific situation of Yushan County Middle School.The results show that 77.70%of track and field athletes have suffered sports injury and periostitis and ligament/muscle strains are the most common forms of injury,and lower limbs are more prone to sports injuries than upper limbs. 展开更多
关键词 Middle School track and field Sports Injuries Preventive Measures
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Study on Entertainment Teaching Experiment for Track and Field in Physical Education Major
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作者 Bin Wang Xia Li 《Open Journal of Applied Sciences》 2012年第4期154-158,共5页
By utilizing the method of documentation, experimental teaching in contrast, mathematical statistics to experimentally study on entertainment teaching experiment for track and field in physical education major, this p... By utilizing the method of documentation, experimental teaching in contrast, mathematical statistics to experimentally study on entertainment teaching experiment for track and field in physical education major, this paper puts forward that this teaching can not only creat the good teaching environment, effectively improve the teaching quality for track and field in P.E. major, but also effectively promote the process of popularity and socialization of track and field. 展开更多
关键词 TEACHING PHYSICAL EDUCATION track and field ENTERTAINMENT
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Investigation and Research on the Ordinary University High Level Track and Field Sports Teams in Sichuan Province
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作者 Dawei Li Bin Wang 《Open Journal of Applied Sciences》 2012年第4期148-153,共6页
by using the method of literature, questionnaire and mathematical statistics and comparative analysis and ?research method of sichuan university high level survey of the Track and field team, sichuan university high l... by using the method of literature, questionnaire and mathematical statistics and comparative analysis and ?research method of sichuan university high level survey of the Track and field team, sichuan university high level Track and field team and the analysis of existing problems and research, in order to sichuan university of high level Track and field teams development to provide the reference. 展开更多
关键词 SICHUAN Ordinary UNIVERSITY The high leve track and field TEAM RESEARCH
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Calculation and Analysis for Temperature Field of Tank Track and Wheels
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作者 毕小平 黄小辉 蒋陆德 《Defence Technology(防务技术)》 SCIE EI CAS 2010年第2期91-95,共5页
To know the temperature status of track and wheels on tank,the finite element calculation of temperature field was implemented with ANSYS software.The detailed temperature distributions for road wheel,drive wheel,idle... To know the temperature status of track and wheels on tank,the finite element calculation of temperature field was implemented with ANSYS software.The detailed temperature distributions for road wheel,drive wheel,idle wheel and track loop were obtained.The effect of factors,such as tank speed,environment temperature,sun radiant energy,ground deformation resistant and tank load,on the temperature of road wheel was studied.The sensitivity analysis shows that the effect of tank load on the temperature is the most,and the effect of ground deformation resistant is the least.The temperature testing device for road wheel on tank was developed to perform the experiments in real time.The calculated temperatures are in accord well with the experimental values. 展开更多
关键词 engineering thermophysics track and wheel temperature field CALCULATION sensitivity analysis
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Analysis on Thermal Current Field in Powertrain Cabin of Tracked Vehicles With Electric Transmission System Configuration-2 被引量:1
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作者 张豫南 李瀚飞 +4 位作者 颜南明 尚颖辉 王冬 李源 袁文涛 《Defence Technology(防务技术)》 SCIE EI CAS 2007年第1期1-6,共6页
The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles. The geometrical model for the power-train cabin is established and the preliminary design for its cooling syst... The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles. The geometrical model for the power-train cabin is established and the preliminary design for its cooling system is implemented. The mathematic model is established for thermal current field computation, simulation and analysis in the powertrain cabin. The three-dimensional structure of the powertrain cabin is optimized. The validity of the cooling system design is proved. The foundation for optimizing the whole electric transmission system configuration is laid. 展开更多
关键词 履带车辆 电传动系统 电传系舱室 热流场 结构优化 数学模型
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基于实测数据的高海拔大日温差地区拱上组合梁桥-无砟轨道体系温度场研究 被引量:3
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作者 勾红叶 陈子豪 +3 位作者 刘畅 肖畅 袁蔚 苏延文 《铁道学报》 EI CAS CSCD 北大核心 2024年第2期159-170,共12页
温度作用是影响桥梁-轨道结构服役性能的重要因素之一。为探究高海拔大日温差地区拱上组合梁桥-无砟轨道体系的温度场变化规律,基于某拟建铁路上承式大跨拱桥桥址处的环境温度持续监测数据与卫星反演得到的太阳辐射数据,建立了考虑太阳... 温度作用是影响桥梁-轨道结构服役性能的重要因素之一。为探究高海拔大日温差地区拱上组合梁桥-无砟轨道体系的温度场变化规律,基于某拟建铁路上承式大跨拱桥桥址处的环境温度持续监测数据与卫星反演得到的太阳辐射数据,建立了考虑太阳辐射阴影遮挡效应的拱上组合梁桥-无砟轨道体系温度场模型,重点分析日温度变化规律和竖向温差分布规律,获得了考虑实测气温和太阳辐射逐时变化的全年日温度场;采用广义帕累托分布对竖向温差样本进行了极值分布估计,确定不同超越概率的竖向温差代表值,提出多折线形式的竖向温度梯度模式。研究结果表明,梯度相较于平原地区更为显著,无砟轨道的遮挡效应使得温度梯度分布上移,钢梁外侧腹板在冬季产生局部梯度作用;基于实测数据的温差极值估计方法考虑了环境温度和太阳辐射对结构温度场的随机影响,可为特殊地区桥梁设计阶段温度作用的计算提供参考。 展开更多
关键词 组合梁桥-无砟轨道体系 温度场 阴影遮挡效应 竖向温度梯度 广义帕累托分布
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A prob of the effect of psychological suggestion in Track and Field Sports
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作者 Chen Lijuan, female, 35 year old, lecturer. Chen Lijuan College of Physical Education, Southwest China Normal University, Chongqing 400715 《西南师范大学学报(自然科学版)》 CAS CSCD 北大核心 1998年第5期125-128,共4页
Modernsportspsychologicalmovesthatathletesconsumenotonlymuchphysicalstrength,butalsogreatpsychologicalenergy... Modernsportspsychologicalmovesthatathletesconsumenotonlymuchphysicalstrength,butalsogreatpsychologicalenergy,whenthey’reintra... 展开更多
关键词 PSYCHOLOGICAL SUGGESTION EFFECT track and field Sports(T.F.S) training contest
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基于机器学习与眼动追踪的认知风格模型构建
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作者 薛耀锋 朱芳清 《现代远程教育研究》 CSSCI 北大核心 2024年第4期94-103,共10页
认知风格反映了学生接近、获取、组织、处理和解释信息的模式,可用来解释和指导学生的行为。将认知风格集成到智能系统中,有助于开发个性化的用户模型,推动智能教育发展。当前有关认知风格自动分类的研究较为匮乏,尚未将机器学习与眼动... 认知风格反映了学生接近、获取、组织、处理和解释信息的模式,可用来解释和指导学生的行为。将认知风格集成到智能系统中,有助于开发个性化的用户模型,推动智能教育发展。当前有关认知风格自动分类的研究较为匮乏,尚未将机器学习与眼动追踪技术联合起来进行应用。基于机器学习与眼动追踪的认知风格模型,选取注视时长、注视点数量、扫视时长、眼跳次数、眼跳距离与瞳孔直径等6个与认知有着密切关系的眼动指标,归一化处理后借助机器学习算法进行认知风格自动分类。实验结果表明:在进行同样时长的视频学习时,不同场认知风格的学习者表现出不同的视觉行为模式;场依存型学习者注视点较为分散,表现出有较多的扫视行为、较少的注视行为、较长的眼跳距离与较大的瞳孔直径变化,信息搜索效率较低;而场独立型学习者有着较为密集与定向的视觉注意模式,信息搜索效率更高。对5种机器学习算法进行性能对比后发现,逻辑回归算法的分类效果最好,准确率达到89.01%,Kappa值达到0.774。该认知风格自动化分类模型既可用于智能学习系统的课程资源优化设计,也可用于个性化学习路径的推荐。未来可整合更多生理数据,通过不同模态数据之间的信息互补,提升数据分析的准确性以及对学习者认知能力评估的可靠性。 展开更多
关键词 智能教育 机器学习 眼动追踪技术 场认知风格 自动化分类
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磁悬浮轨道梁均匀温度及温差分量极值研究
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作者 戴公连 罗泽江 +2 位作者 王芬 何昌林 张昂 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第6期2359-2370,共12页
与一般公铁桥梁不同,磁悬浮轨道梁的温度场会受到周围磁场与功能件升温的影响。由于我国规范暂未对磁浮轨道梁均匀温度和温差分量的极值作出明确规定,研究具有概率保证的温度分量代表值具有重要意义。根据长沙磁浮运营线某混凝土箱梁1... 与一般公铁桥梁不同,磁悬浮轨道梁的温度场会受到周围磁场与功能件升温的影响。由于我国规范暂未对磁浮轨道梁均匀温度和温差分量的极值作出明确规定,研究具有概率保证的温度分量代表值具有重要意义。根据长沙磁浮运营线某混凝土箱梁1年多的现场温度监测数据,分析梁体均匀温度与竖向等效线性温差的时变特征。研究分别采用单变量线性回归法(ULR法)和梯度提升回归树法(GBRT法)建立基于气象因素的结构温度分量预测模型,对比发现GBRT法不仅能提高均匀温度的预测精度,还能克服ULR法无法预测竖向等效线性温差的局限性。而后将1960—2019年的长期气象数据输入到建立好的GBRT预测模型中,得到磁浮箱梁各温度分量60年的长期预测值,经整理后得到均匀温度和竖向等效线性温差的日极值、年极值样本。结合最大熵极值模型和Fourier函数得到各温度分量的日极值时变曲线,对年极值样本建立最大熵模型并确定百年重现期下的温度分量代表值。研究结果表明:磁浮箱梁均匀温度呈现以年为周期的季节性变化,竖向等效线性温差受太阳辐射影响,呈夏季高、冬季低的特点;百年重现期下磁浮箱梁均匀温度和竖向等效线性温差的代表值分别为44.4℃、8.6℃。该方法结合GBRT算法和最大熵极值模型,解决了极值分析中年极值样本不足的问题,结果可为磁浮轨道梁的温度变形设计提供参考。 展开更多
关键词 磁悬浮轨道梁 现场试验 均匀温度 等效线性温差 GBRT算法 最大熵模型 极值分析
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重载列车编组与运行对双线桥动力响应的影响
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作者 肖烨 罗小勇 +1 位作者 范亚坤 罗亦泳 《铁道工程学报》 EI CSCD 北大核心 2024年第7期34-40,46,共8页
研究目的:为研究重载列车编组与运行对双线桥梁动力响应的影响,以朔黄重载铁路线上一座32 m预应力混凝土双线简支T梁为研究对象,建立重载列车-轨道-桥梁耦合有限元模型,并通过现场试验验证有限元模型的准确性,研究重载列车通过双线桥梁... 研究目的:为研究重载列车编组与运行对双线桥梁动力响应的影响,以朔黄重载铁路线上一座32 m预应力混凝土双线简支T梁为研究对象,建立重载列车-轨道-桥梁耦合有限元模型,并通过现场试验验证有限元模型的准确性,研究重载列车通过双线桥梁时的动力响应,分析重载列车不同编组方式、重载列车双线对开运行等因素对双线桥梁动力响应的影响规律。研究结论:(1)动力响应计算结果与实测值吻合较好,表明所建立的重载列车-轨道-桥梁耦合有限元模型的可靠性高;(2)重车编组对桥梁的位移响应和动应变影响最大,对加速度的影响最小;空车编组对桥梁的加速度响应最大;空重混编次之,其中重车在前空车在后的混合编组对空车的位移响应影响较大,可能引起空车脱轨;(3)重车空车双线对开运行下桥梁的动力响应随着车速的提高而增加,与重车单线运行下桥梁的动力响应规律相似;在相同车速下,双线对开运行下桥梁的跨中竖向动力响应峰值均比重车单线运行下略大,而横向动力响应峰值比重车单线运行下小;(4)当重车与空车入桥距离差值为车体长度的整数倍时,桥梁的动力响应峰值与重车空车同时上桥时基本相等;当入桥距离差值为车体长度一半的整数倍时,桥梁的动力响应峰值有所降低;(5)本研究成果可为新建重载铁路双线桥梁的设计提供参考。 展开更多
关键词 列车编组 双线桥梁 有限元模型 现场试验 动力响应
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激活后增强训练法在田径运动中的应用与效果研究
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作者 关道权 费晓艳 《齐齐哈尔大学学报(自然科学版)》 2024年第5期76-80,共5页
为了更加有效地提高体育专业学生的运动成绩,优化田径运动训练方法,引入了激活后增强训练法,通过实验与常规抗阻训练的训练效果进行对比。实验结果表明,激活后增强训练法能够更有效地增强爆发力,提高体育项目成绩。激活后增强训练法在... 为了更加有效地提高体育专业学生的运动成绩,优化田径运动训练方法,引入了激活后增强训练法,通过实验与常规抗阻训练的训练效果进行对比。实验结果表明,激活后增强训练法能够更有效地增强爆发力,提高体育项目成绩。激活后增强训练法在研究中的平均提升幅度达到了8.68%,在相同的测试项目中,相较于传统抗阻训练法的提升幅度提高了4.58%。激活后增强训练法不仅结合了抗阻训练的优点,同时引入了神经-肌肉的“激活”概念,能够为体育训练方法的改革提供理论和数据支持。 展开更多
关键词 激活后增强训练法 田径运动 爆发力
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考虑崎岖地形的月球车路径规划与跟踪控制研究
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作者 陈金宝 刘彦清 +1 位作者 邢宏军 徐宇哲 《载人航天》 CSCD 北大核心 2024年第5期624-631,共8页
为优化月球车运动路径,避开月球陨石坑和高地等月面静态障碍物,以安全、高效抵达目标任务点,提出了一种结合A∗算法和人工势场法的融合算法。首先,利用A∗算法在栅格地图中生成从起点到终点的最优安全路径;然后,设计全局路径分割方法,按... 为优化月球车运动路径,避开月球陨石坑和高地等月面静态障碍物,以安全、高效抵达目标任务点,提出了一种结合A∗算法和人工势场法的融合算法。首先,利用A∗算法在栅格地图中生成从起点到终点的最优安全路径;然后,设计全局路径分割方法,按阶段进行基于人工势场法的局部路径规划,并基于Lyapunov稳定性理论设计了全局渐进稳定的轨迹跟踪控制律;最后,通过Blender软件制作仿真月表环境,并使用ROS Gazebo仿真平台进行轨迹跟踪仿真验证。仿真结果表明:提出的融合算法生成的移动路径相较于普通A∗算法路径更短,转折次数更少,并加入人工势场算法进行局部避障,极大提高了月球车运动安全性,验证了所提出算法的可行性和有效性。 展开更多
关键词 月球车 路径规划 轨迹跟踪 A∗算法 人工势场法
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应用于无人机全局航迹规划的改进双向RRTs算法
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作者 姜香菊 黄炳德 杨潇洁 《机械科学与技术》 CSCD 北大核心 2024年第5期897-903,共7页
针对无人机复杂环境下的全局航迹规划问题,将人工势场法与双向RRTs(Rapidly-exploring random trees)算法结合,提出一种改进双向RRTs算法。首先,目标偏置策略引导采样点以一定概率顺着目标点生成,同时随机树新节点受到障碍物斥力和目标... 针对无人机复杂环境下的全局航迹规划问题,将人工势场法与双向RRTs(Rapidly-exploring random trees)算法结合,提出一种改进双向RRTs算法。首先,目标偏置策略引导采样点以一定概率顺着目标点生成,同时随机树新节点受到障碍物斥力和目标点引力的合力影响有效避开障碍物生长,提高航迹搜寻效率,其次对随机树的节点扩展考虑了无人机飞行性能约束条件,最后采用3阶贝塞尔函数进一步航迹优化。仿真结果表明:二维和三维复杂环境中改进双向RRTs算法相比传统RRT、双向RRTs算法航迹搜索耗时减少了71.3%、24.7%和41.0%、18.6%,验证了改进算法全局搜索能力的快速性和有效性,能很好的应用于无人机离线全局航迹规划场合。 展开更多
关键词 无人机 RRT算法 人工势场 目标偏置 航迹平滑
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基于升降轨SAR数据的地下核爆参数反演与3D形变监测方法
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作者 贺黎明 康家帅 +1 位作者 郭聪 王兴杰 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第3期382-390,共9页
以朝鲜第6次地下核试验为例,基于升降轨ALOS-2 SAR数据,首先利用D-InSAR技术获取核试验场的视线向形变,以此为基础,基于贝叶斯反演方法确定核爆参数,然后引入POT技术测量核试验场方位向和距离向形变,最后,融合D-InSAR与POT结果计算核试... 以朝鲜第6次地下核试验为例,基于升降轨ALOS-2 SAR数据,首先利用D-InSAR技术获取核试验场的视线向形变,以此为基础,基于贝叶斯反演方法确定核爆参数,然后引入POT技术测量核试验场方位向和距离向形变,最后,融合D-InSAR与POT结果计算核试验地表三维形变场.研究发现,核爆位于朝鲜丰溪里试验场万塔山下,其坐标为东经129.0792°,北纬41.3026°,深度约为550 m,核爆导致发生水平方向位移约3 m,垂直方向位移约1 m.结果表明天基SAR遥感技术,特别是长波段SAR,在地下核试验监测中具有重要的应用价值,可为地下核试验监测提供新思路. 展开更多
关键词 地下核试验 INSAR 核爆参数反演 像素偏移量跟踪 三维形变场
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桥上CRTSⅠ型双块式无砟轨道早期开裂行为研究 被引量:2
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作者 张凯 元强 +3 位作者 李秋义 黄庭杰 左胜浩 黄志斌 《铁道学报》 EI CAS CSCD 北大核心 2024年第3期41-49,共9页
以桥上CRTSⅠ型双块式无砟轨道为研究对象,基于混凝土早期性能发展基本理论,利用Ansys建立三维温度场与应力场分析模型,考虑养护方法、拆模龄期、拆模温度与钢筋直径等参数影响,对双块式无砟轨道早期开裂行为进行数值模拟。结果表明:无... 以桥上CRTSⅠ型双块式无砟轨道为研究对象,基于混凝土早期性能发展基本理论,利用Ansys建立三维温度场与应力场分析模型,考虑养护方法、拆模龄期、拆模温度与钢筋直径等参数影响,对双块式无砟轨道早期开裂行为进行数值模拟。结果表明:无砟道床不同位置处混凝土主拉应力整体呈循环上升趋势;拆模前后混凝土应力时程曲线波动程度差异较大,拆模后4 h内道床混凝土主拉应力时程曲线出现明显增长。合理选用养护方式可有效降低道床板早期开裂风险;伴随着拆模龄期的延长与拆模温度的升高,拆模后无砟道床4 h内温度改变量与道床混凝土开裂风险均呈降低趋势;相同配筋率下,减小钢筋直径可降低桥上CRTSⅠ型双块式无砟轨道早期开裂风险。 展开更多
关键词 桥上双块式无砟轨道 早期温度场 早期开裂 数值模拟
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