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Improvement of Binocular Reconstruction Algorithm for Measuring 3D Pavement Texture Using a Single Laser Line Scanning Constraint 被引量:1
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作者 Yuanyuan Wang RuiWang +1 位作者 Xiaofeng Ren Junan Lei 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第8期1951-1972,共22页
The dense and accurate measurement of 3D texture is helpful in evaluating the pavement function.To form dense mandatory constraints and improve matching accuracy,the traditional binocular reconstruction technology was... The dense and accurate measurement of 3D texture is helpful in evaluating the pavement function.To form dense mandatory constraints and improve matching accuracy,the traditional binocular reconstruction technology was improved threefold.First,a single moving laser line was introduced to carry out global scanning constraints on the target,which would well overcome the difficulty of installing and recognizing excessive laser lines.Second,four kinds of improved algorithms,namely,disparity replacement,superposition synthesis,subregion segmentation,and subregion segmentation centroid enhancement,were established based on different constraint mechanism.Last,the improved binocular reconstruction test device was developed to realize the dual functions of 3D texture measurement and precision self-evaluation.Results show that compared with traditional algorithms,the introduction of a single laser line scanning constraint is helpful in improving the measurement’s accuracy.Among various improved algorithms,the improvement effect of the subregion segmentation centroid enhancement method is the best.It has a good effect on both overall measurement and single pointmeasurement,which can be considered to be used in pavement function evaluation. 展开更多
关键词 3D pavement texture binocular reconstruction algorithm single laser line scanning constraint improved stereo matching
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Structural plane recognition from three-dimensional laser scanning points using an improved region-growing algorithm based on the robust randomized Hough transform 被引量:1
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作者 XU Zhi-hua GUO Ge +3 位作者 SUN Qian-cheng WANG Quan ZHANG Guo-dong YE Run-qing 《Journal of Mountain Science》 SCIE CSCD 2023年第11期3376-3391,共16页
The staggered distribution of joints and fissures in space constitutes the weak part of any rock mass.The identification of rock mass structural planes and the extraction of characteristic parameters are the basis of ... The staggered distribution of joints and fissures in space constitutes the weak part of any rock mass.The identification of rock mass structural planes and the extraction of characteristic parameters are the basis of rock-mass integrity evaluation,which is very important for analysis of slope stability.The laser scanning technique can be used to acquire the coordinate information pertaining to each point of the structural plane,but large amount of point cloud data,uneven density distribution,and noise point interference make the identification efficiency and accuracy of different types of structural planes limited by point cloud data analysis technology.A new point cloud identification and segmentation algorithm for rock mass structural surfaces is proposed.Based on the distribution states of the original point cloud in different neighborhoods in space,the point clouds are characterized by multi-dimensional eigenvalues and calculated by the robust randomized Hough transform(RRHT).The normal vector difference and the final eigenvalue are proposed for characteristic distinction,and the identification of rock mass structural surfaces is completed through regional growth,which strengthens the difference expression of point clouds.In addition,nearest Voxel downsampling is also introduced in the RRHT calculation,which further reduces the number of sources of neighborhood noises,thereby improving the accuracy and stability of the calculation.The advantages of the method have been verified by laboratory models.The results showed that the proposed method can better achieve the segmentation and statistics of structural planes with interfaces and sharp boundaries.The method works well in the identification of joints,fissures,and other structural planes on Mangshezhai slope in the Three Gorges Reservoir area,China.It can provide a stable and effective technique for the identification and segmentation of rock mass structural planes,which is beneficial in engineering practice. 展开更多
关键词 3D laser scanning Rock discontinuity structural plane Intelligent recognition Robust randomized Hough transform Improved region growing algorithm
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Adaptive Window Based 3-D Feature Selection for Multispectral Image Classification Using Firefly Algorithm 被引量:1
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作者 M.Rajakani R.J.Kavitha A.Ramachandran 《Computer Systems Science & Engineering》 SCIE EI 2023年第1期265-280,共16页
Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafte... Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafted feature sets are used which are not adaptive for different image domains.To overcome this,an evolu-tionary learning method is developed to automatically learn the spatial-spectral features for classification.A modified Firefly Algorithm(FA)which achieves maximum classification accuracy with reduced size of feature set is proposed to gain the interest of feature selection for this purpose.For extracting the most effi-cient features from the data set,we have used 3-D discrete wavelet transform which decompose the multispectral image in all three dimensions.For selecting spatial and spectral features we have studied three different approaches namely overlapping window(OW-3DFS),non-overlapping window(NW-3DFS)adaptive window cube(AW-3DFS)and Pixel based technique.Fivefold Multiclass Support Vector Machine(MSVM)is used for classification purpose.Experiments con-ducted on Madurai LISS IV multispectral image exploited that the adaptive win-dow approach is used to increase the classification accuracy. 展开更多
关键词 Multispectral image modifiedfirefly algorithm 3-D feature extraction feature selection multiclass support vector machine CLASSIFICATION
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Asymmetric image encryption algorithm based on a new three-dimensional improved logistic chaotic map 被引量:1
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作者 叶国栋 吴惠山 +1 位作者 黄小玲 Syh-Yuan Tan 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期153-163,共11页
Based on some analyses of existing chaotic image encryption frameworks and a new designed three-dimensional improved logistic chaotic map(3D-ILM),an asymmetric image encryption algorithm using public-key Rivest–Shami... Based on some analyses of existing chaotic image encryption frameworks and a new designed three-dimensional improved logistic chaotic map(3D-ILM),an asymmetric image encryption algorithm using public-key Rivest–Shamir–Adleman(RSA)is presented in this paper.In the first stage,a new 3D-ILM is proposed to enhance the chaotic behavior considering analysis of time sequence,Lyapunov exponent,and Shannon entropy.In the second stage,combined with the public key RSA algorithm,a new key acquisition mathematical model(MKA)is constructed to obtain the initial keys for the 3D-ILM.Consequently,the key stream can be produced depending on the plain image for a higher security.Moreover,a novel process model(NPM)for the input of the 3D-ILM is built,which is built to improve the distribution uniformity of the chaotic sequence.In the third stage,to encrypt the plain image,a pre-process by exclusive OR(XOR)operation with a random matrix is applied.Then,the pre-processed image is performed by a permutation for rows,a downward modulo function for adjacent pixels,a permutation for columns,a forward direction XOR addition-modulo diffusion,and a backward direction XOR addition-modulo diffusion to achieve the final cipher image.Moreover,experiments show that the the proposed algorithm has a better performance.Especially,the number of pixels change rate(NPCR)is close to ideal case 99.6094%,with the unified average changing intensity(UACI)close to 33.4634%,and the information entropy(IE)close to 8. 展开更多
关键词 three-dimensional improved logistic chaotic map(3D-ILM) Rivest–Shamir–Adleman(RSA)algorithm image encryption CONFUSION ENTROPY
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A New Three-Dimensional(3D)Printing Prepress Algorithm for Simulation of Planned Surgery for Congenital Heart Disease
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作者 Vitaliy Suvorov Olga Loboda +1 位作者 Maria Balakina Igor Kulczycki 《Congenital Heart Disease》 SCIE 2023年第5期491-505,共15页
Background:Three-dimensional printing technology may become a key factor in transforming clinical practice and in significant improvement of treatment outcomes.The introduction of this technique into pediatric cardiac... Background:Three-dimensional printing technology may become a key factor in transforming clinical practice and in significant improvement of treatment outcomes.The introduction of this technique into pediatric cardiac surgery will allow us to study features of the anatomy and spatial relations of a defect and to simulate the optimal surgical repair on a printed model in every individual case.Methods:We performed the prospective cohort study which included 29 children with congenital heart defects.The hearts and the great vessels were modeled and printed out.Measurements of the same cardiac areas were taken in the same planes and points at multislice computed tomography images(group 1)and on printed 3D models of the hearts(group 2).Pre-printing treatment of the multislice computed tomography data and 3D model preparation were performed according to a newly developed algorithm.Results:The measurements taken on the 3D-printed cardiac models and the tomographic images did not differ significantly,which allowed us to conclude that the models were highly accurate and informative.The new algorithm greatly simplifies and speeds up the preparation of a 3D model for printing,while maintaining high accuracy and level of detail.Conclusions:The 3D-printed models provide an accurate preoperative assessment of the anatomy of a defect in each case.The new algorithm has several important advantages over other available programs.They enable the development of customized preliminary plans for surgical repair of each specific complex congenital heart disease,predict possible issues,determine the optimal surgical tactics,and significantly improve surgical outcomes. 展开更多
关键词 3D printing imaging in cardiac surgery congenital heart disease modelling in cardiac surgery pediatric cardiology algorithmic modelling of the heart medical imaging 3D modelling
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Construction of Ship Target Image Library Based on 3DS MAX and AP Algorithm
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作者 Chao Ji Weixing Xia Zhengping Tang 《Modern Electronic Technology》 2023年第2期20-25,共6页
To achieve accurate classification and recognition of ship target types,it is necessary to establish a sample library of ship targets to be identified.On the basis of exploring the principles of building a ship target... To achieve accurate classification and recognition of ship target types,it is necessary to establish a sample library of ship targets to be identified.On the basis of exploring the principles of building a ship target image library,the paper determines the sample set.Using 3DS MAX software as the platform,combined with the accurate 3D model of the ship in an offline state,the software fully utilizes its own rendering and animation functions to achieve the automatic generation of multi-view and multi-scale views of ship targets.To reduce the storage capacity of the image database,a construction method of the ship target image database based on the AP algorithm is presented.The algorithm can obtain the optimal cluster number,reduce the data storage capacity of the image database,and save the calculation amount for the subsequent matching calculation. 展开更多
关键词 AP algorithm Ship target image library 3DS MAX Image recognition
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三角形编织工艺数字化建模方法
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作者 王辉 周伟 +2 位作者 陈一哲 龙晚昕 王金伙 《纺织学报》 EI CAS CSCD 北大核心 2024年第6期75-81,共7页
三维旋转式编织工艺按角轮缺口数分为三角形、四角形和六角形编织工艺,其中三角形编织工艺研究较少。为探索基于三角形编织工艺的预制体结构,基于Python语言和CATIA开发编织工艺软件,获得预制体几何结构。角轮和交换轮交替旋转,驱动携... 三维旋转式编织工艺按角轮缺口数分为三角形、四角形和六角形编织工艺,其中三角形编织工艺研究较少。为探索基于三角形编织工艺的预制体结构,基于Python语言和CATIA开发编织工艺软件,获得预制体几何结构。角轮和交换轮交替旋转,驱动携纱器在底盘中运动,使纱线相互交织形成预制体。对角轮、交换轮、携纱器的编号和运动状态进行数字化编码,研究不同旋转状态下携纱器的交换规律。携纱器轨迹与编织节点高度共同确定了织物空间拓扑结构,采用三次B-spline曲线对纱线空间轨迹进行拟合,建立预制体的参数化几何模型。结果表明:采用三角形编织工艺获得的预制体结构紧凑,织物几何模型与试验样件一致性较好,验证了建模方法的精度。 展开更多
关键词 三维编织 预制体 编织算法 细观结构模型 工艺软件
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基于改进果蝇算法的高可靠无人机分簇路由协议
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作者 袁学松 《重庆科技大学学报(自然科学版)》 CAS 2024年第5期58-64,共7页
针对复杂无人机集群环境下各节点终端之间缺少可靠的端到端通信路径问题,提出了一种基于改进果蝇算法的高可靠无人机分簇路由协议(HCRFA)。首先,通过改进经典的加权分簇算法,使用节点运动方向、节点平均距离和节点剩余能量等确定簇首和... 针对复杂无人机集群环境下各节点终端之间缺少可靠的端到端通信路径问题,提出了一种基于改进果蝇算法的高可靠无人机分簇路由协议(HCRFA)。首先,通过改进经典的加权分簇算法,使用节点运动方向、节点平均距离和节点剩余能量等确定簇首和簇规模,并设计入簇规则和簇维护规则;其次,根据跳数、地理位置等信息设计簇内路由机制,利用仿生学集群优化算法制定簇间路由机制;最后,使用NS-3进行仿真实验。仿真实验结果表明,相较于基于平面路由的路由协议、经典加权分簇路由结合地理位置辅助路由协议和改进的容忍时延网络分簇路由协议,HCRFA的数据包到达率和网络开销都有所改善,簇结构更加稳定。 展开更多
关键词 无人机集群 果蝇算法 加权分簇算法 NS-3
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多机器人协同路径的时域协作-势场A*规划
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作者 吴静莉 《机械设计与制造》 北大核心 2024年第1期337-341,共5页
为了减小多机器人协同工作路径长度并提高路径平滑度,提出了基于时域协作-势场A*算法的多机器人协同规划方法。建立了机器人工作环境的栅格模型,分析了传统A*算法辅助信息不充分的问题。为了充分利用环境中的障碍物和目标点位置等先验信... 为了减小多机器人协同工作路径长度并提高路径平滑度,提出了基于时域协作-势场A*算法的多机器人协同规划方法。建立了机器人工作环境的栅格模型,分析了传统A*算法辅助信息不充分的问题。为了充分利用环境中的障碍物和目标点位置等先验信息,基于势场法将障碍物和目标点信息引入到A*算法辅助信息中,提出了基于势场A*算法的单机器人路径规划方法。使用三维时空图代替二维平面图,可以有效判断出多机器人碰撞问题,并根据碰撞类型制定了避撞策略。经验证,势场A*算法规划的路径长度和平滑度均优于传统A*算法、文献[11]蚁群算法;在多机器人协同路径规划中,在规划出各机器人最优路径基础上,可以有效解决机器人之间的碰撞问题。实验结果验证了时域协作-势场A*算法在多机器人协同路径规划中的有效性和优越性。 展开更多
关键词 多机器人 协同规划 时域协作 势场A*算法 三维时空图
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高分三号数据分布式负载均衡并行转换算法
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作者 邱祥峰 《厦门理工学院学报》 2024年第5期33-39,共7页
针对PolSARpro软件原有高分三号数据转换模块无法适应分布式环境及数据转换效率相对较低的问题,提出一种基于MPI、MapReduce和OpenMP并按照该软件的数据格式要求进行分布式负载均衡的并行转换算法。该算法外层采用MPI按任务分布式计算,... 针对PolSARpro软件原有高分三号数据转换模块无法适应分布式环境及数据转换效率相对较低的问题,提出一种基于MPI、MapReduce和OpenMP并按照该软件的数据格式要求进行分布式负载均衡的并行转换算法。该算法外层采用MPI按任务分布式计算,中间层采用MapReduce按景并行处理,内层采用OpenMP按极化方式并行计算,并采用“Z”字形数据负载均衡策略,将高分三号不同成像模式下的多极化数据快速精确定标及格式转换,以抗数据偏斜。实际数据的测试结果表明,该算法的整体性能提升了约50%,验证了算法的可行性、高效性和正确性。 展开更多
关键词 高分三号卫星 合成孔径雷达 分布式负载均衡 并行转换算法 共享存储并行编程 映射归约编程模型 消息传递接口
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RP-3航空煤油/O_(2)的简化反应机理优化与验证
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作者 曾文 徐紫馨 +2 位作者 张鑫炜 胡斌 常亚超 《燃烧科学与技术》 CAS CSCD 北大核心 2024年第6期539-549,共11页
采用RP-3航空煤油的简化反应机理对多工况条件下RP-3航空煤油/氧气混合物的氧化、着火延迟与层流燃烧特性进行了数值计算,并与相应试验数据进行了对比验证;同时,采用敏感性分析方法对该简化反应机理中燃料相关骨架反应机理中的基元反应... 采用RP-3航空煤油的简化反应机理对多工况条件下RP-3航空煤油/氧气混合物的氧化、着火延迟与层流燃烧特性进行了数值计算,并与相应试验数据进行了对比验证;同时,采用敏感性分析方法对该简化反应机理中燃料相关骨架反应机理中的基元反应进行了敏感性分析;采用遗传算法,对重要的基元反应速率常数进行优化,形成了优化后的RP-3航空煤油/氧气混合物的简化反应机理.结果表明,大部分工况条件下初始简化反应机理对RP-3航空煤油/氧气混合物氧化过程中主要组分浓度、着火延迟时间以及层流燃烧速度的预测值与相应试验值存在较大误差.同时,优化后的简化反应机理对多工况条件下RP-3航空煤油/氧气混合物氧化过程中的主要组分浓度、着火延迟时间及层流燃烧速度的预测值与相应试验值吻合较好. 展开更多
关键词 RP-3航空煤油 简化反应机理 敏感性分析 遗传算法 燃烧特性
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基于改进鲸鱼优化算法的码垛机器人时间最优轨迹规划
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作者 汤兆平 孟鑫 +1 位作者 孙剑萍 彭俊 《科学技术与工程》 北大核心 2024年第14期5882-5891,共10页
码垛机器人在运行轨迹过程中所消耗的时间直接影响到了其工作效率,针对码垛机器人的轨迹规划的时间问题,提出了一种改进的鲸鱼优化算法对时间进行优化。在基本的鲸鱼优化算法基础上,利用混沌映射初始化种群,引入自适应的权重和改进收敛... 码垛机器人在运行轨迹过程中所消耗的时间直接影响到了其工作效率,针对码垛机器人的轨迹规划的时间问题,提出了一种改进的鲸鱼优化算法对时间进行优化。在基本的鲸鱼优化算法基础上,利用混沌映射初始化种群,引入自适应的权重和改进收敛因子,以提高算法的求解精度、收敛速度和全局搜索能力。首先,根据D-H参数法建立机器人的运动学模型;其次,在关节空间中利用3-5-3次多项式插值函数对机器人末端执行器经过的路径点进行规划,然后采用改进的鲸鱼优化算法对时间进行优化。最后通过MATLAB软件进行效果仿真和对比。结果表明,与其他同类的算法相比,改进的鲸鱼优化算法的求解精度更高,收敛速度更快。将该方法与轨迹优化结合,与未采用算法优化的3-5-3多项式轨迹规划所需要的运行时间相比缩短了22.46%,且各个关节轨迹平稳连续,验证了该轨迹规划方法的有效性。 展开更多
关键词 轨迹规划 改进鲸鱼算法 3-5-3次多项式 时间优化
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中国人群非ST 段抬高型心肌梗死诊断中两种高敏心肌肌钙蛋白0/3小时流程的比较
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作者 蔡瑶瑶 蔺亚晖 +10 位作者 杨晴 詹红 刘敏 王书奎 刘才冬 冯广迅 张涛 杨艳敏 朱俊 周洲 梁岩 《中国循环杂志》 CSCD 北大核心 2024年第11期1070-1077,共8页
目的:比较2015年欧洲心脏病学会(ESC)非ST段抬高型急性冠状动脉综合征(NSTE-ACS)管理指南(2015年ESC指南)和2021年《心肌肌钙蛋白实验室检测与临床应用中国专家共识》(2021年中国共识)推荐的高敏心肌肌钙蛋白(hs-cTn)0/3 h流程,在疑似... 目的:比较2015年欧洲心脏病学会(ESC)非ST段抬高型急性冠状动脉综合征(NSTE-ACS)管理指南(2015年ESC指南)和2021年《心肌肌钙蛋白实验室检测与临床应用中国专家共识》(2021年中国共识)推荐的高敏心肌肌钙蛋白(hs-cTn)0/3 h流程,在疑似急性冠状动脉综合征(ACS)患者中对非ST段抬高型心肌梗死(NSTEMI)的诊断效能及其对主要不良心血管事件(MACE)的预测价值。方法:本研究为一项多中心前瞻性观察性研究,共纳入2017年1月至2020年9月三个临床中心共1527例疑似ACS患者。患者均在就诊时(0 h)及3 h行ARCHITECT血浆高敏心肌肌钙蛋白Ⅰ(hs-cTnI)水平检测(检验判定)。以临床判定(心脏科专家独立于检测结果进行临床判定)作为金标准,比较两种诊断流程的灵敏度、特异度及一致率,并分析其对30 d及180 d MACE的预测价值。MACE为心血管死亡、心肌梗死及计划外冠状动脉血运重建的复合终点。结果:根据临床判定,NSTEMI患者400例,非NSTEMI患者1127例。2021年中国共识推荐的0/3 h流程在诊断NSTEMI的灵敏度上高于2015年ESC指南[91.50%(95%CI:88.32%~94.04%)vs.87.75%(95%CI:84.13%~90.80%)],而在特异度上略低[93.88%(95%CI:92.32%~95.21%)vs.95.56%(95%CI:94.19%~96.69%)],两种差异均有统计学意义(P均<0.001)。在30 d和180 d的随访中,两种流程中诊断为NSTEMI的患者MACE发生率均高于排除NSTEMI的患者,差异具有统计学意义(P<0.001)。2015 ESC年指南推荐流程排除的NSTEMI患者在30 d和180 d的MACE发生率分别为0.19%和1.12%,诊断的NSTEMI患者分别为2.89%和3.68%;而2021年中国共识推荐流程排除的NSTEMI患者在30 d和180 d的MACE发生率分别为0.096%和0.770%,诊断的NSTEMI患者分别为2.91%和4.36%。Cox分析显示,两种流程诊断的NSTEMI组在180 d时MACE的HR分别为3.418(95%CI:1.581~7.390,P=0.002)和5.892(95%CI:2.562~13.551,P<0.001),均显著高于排除NSTEMI组。结论:2021年中国共识推荐的0/3 h流程在诊断灵敏度上优于2015年ESC指南推荐流程,尽管前者在特异度上略低。两种流程均能有效预测180 d内MACE,但基于本研究数据,中国共识推荐流程可能在预测MACE风险方面更为敏感,经该方法排除NSTEMI诊断的患者具更低的MACE事件,提示其在临床实践中的应用可能更有助于患者的长期安全管理。 展开更多
关键词 高敏心肌肌钙蛋白I 非ST段抬高型心肌梗死 中国人群 0/3 h诊断流程
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基于传感器阵列及神经网络算法的NH_(3)和NO_(2)混合气体体积分数识别
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作者 包叶朋 张毅然 +2 位作者 陈婷 湛日景 林赫 《传感器与微系统》 CSCD 北大核心 2024年第10期150-154,共5页
针对电阻型气体传感器具有的交叉敏感性,开发了基于WO_(3)传感器阵列及神经网络算法的NH_(3),NO_(2)混合气体体积分数预测技术。采用火焰合成法合成了La掺杂的WO_(3)敏感材料并制备了气体传感器,与商用MQ—137电阻型气体传感器组成阵列... 针对电阻型气体传感器具有的交叉敏感性,开发了基于WO_(3)传感器阵列及神经网络算法的NH_(3),NO_(2)混合气体体积分数预测技术。采用火焰合成法合成了La掺杂的WO_(3)敏感材料并制备了气体传感器,与商用MQ—137电阻型气体传感器组成阵列。通过提取特征值、神经网络训练,构建传感器阵列输出与气体体积分数的映射模型,并使用该模型由传感器阵列的响应结果对NH_(3),NO_(2)混合气体进行体积分数预测。实验结果表明:经训练后的神经网络能对NH_(3),NO_(2)混合气体中各组分体积分数进行有效预测,平均预测误差分别为3.64%和2.48%。本文所开发的传感器阵列及神经网络算法有效避免了电阻型传感器选择性差的局限,实现了对NH_(3)和NO_(2)混合气体的高效识别和体积分数测量。 展开更多
关键词 传感器阵列 二氧化氮 氨气 交叉敏感性 神经网络算法
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基于改进麻雀搜索算法的3DDV-Hop定位算法
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作者 高翔宇 韩慧子 +1 位作者 孟亚男 刘美 《计算机测量与控制》 2024年第5期246-252,共7页
针对经典3DDV-Hop算法定位精度不高的问题,提出一种基于改进麻雀搜索算法优化的改进的3DDV-Hop算法;算法首先通过多通信半径优化传感器节点之间跳数,并且在平均跳距计算过程中引入动态加权因子提高平均跳距计算精度,其次在麻雀搜索算法... 针对经典3DDV-Hop算法定位精度不高的问题,提出一种基于改进麻雀搜索算法优化的改进的3DDV-Hop算法;算法首先通过多通信半径优化传感器节点之间跳数,并且在平均跳距计算过程中引入动态加权因子提高平均跳距计算精度,其次在麻雀搜索算法的基础上融合反向学习策略与萤火虫算法分别对麻雀搜索算法的种群与位置更新迭代进行优化,最后将未知节点坐标计算问题转化成改进后的麻雀搜索算法寻优问题,利用改进后的麻雀搜索算法替代最小二乘法计算未知节点坐标,进一步提高未知节点位置计算精度;经过MATLAB仿真验证,改进算法对比于经典3DDV-Hop算法和相关算法,定位精度得到有效提高。 展开更多
关键词 无线传感器网络 3DDV-Hop 麻雀搜索算法 节点定位 萤火虫算法
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联合优化无人机位置和功率的用户吞吐量最大化方法
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作者 陈丹 杨洪朝 谢英辉 《宇航计测技术》 CSCD 2024年第3期82-88,共7页
因移动便捷、高视距通信概率等优势,无人机(Unmanned Aerial Vehicle,UAV)在应急通信中发挥重要作用。为此,提出联合优化UAVs位置和传输功率的吞吐量最大化(Joint optimization of UAV 3-D Position and Transmit powers for throughput... 因移动便捷、高视距通信概率等优势,无人机(Unmanned Aerial Vehicle,UAV)在应急通信中发挥重要作用。为此,提出联合优化UAVs位置和传输功率的吞吐量最大化(Joint optimization of UAV 3-D Position and Transmit powers for throughput Maximization,JPTM)方法,进而提高地面用户的吞吐量。先构建一个联合UAVs三维位置和传输功率的优化问题。考虑到该问题的非凸优化性,将其分解为两个子问题。用Mean-Shift算法求解第一个问题,获取最优的UAVs水平位置。采用分而治之策略,将第二个子问题再分解,并利用一阶泰勒级数展开对两个子问题进行近似处理,形成标准凸化问题,然后利用CVX工具求解。性能分析表明,相比于基于圆形堆积理论部署UAVs策略(Circle Packing Theorem-based Deployment,CPTD)和基于多变量仿真的能效UAVs部署策略(Energy-Efficient Variable simultaneous Deployment,EEVD)算法,JPTM算法提高了地面用户的吞吐量。 展开更多
关键词 无人机通信 三维位置部署 传输功率优化 MEAN-SHIFT算法 一阶泰勒级数展开
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Optimized air-ground data fusion method for mine slope modeling
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作者 LIU Dan HUANG Man +4 位作者 TAO Zhigang HONG Chenjie WU Yuewei FAN En YANG Fei 《Journal of Mountain Science》 SCIE CSCD 2024年第6期2130-2139,共10页
Refined 3D modeling of mine slopes is pivotal for precise prediction of geological hazards.Aiming at the inadequacy of existing single modeling methods in comprehensively representing the overall and localized charact... Refined 3D modeling of mine slopes is pivotal for precise prediction of geological hazards.Aiming at the inadequacy of existing single modeling methods in comprehensively representing the overall and localized characteristics of mining slopes,this study introduces a new method that fuses model data from Unmanned aerial vehicles(UAV)tilt photogrammetry and 3D laser scanning through a data alignment algorithm based on control points.First,the mini batch K-Medoids algorithm is utilized to cluster the point cloud data from ground 3D laser scanning.Then,the elbow rule is applied to determine the optimal cluster number(K0),and the feature points are extracted.Next,the nearest neighbor point algorithm is employed to match the feature points obtained from UAV tilt photogrammetry,and the internal point coordinates are adjusted through the distanceweighted average to construct a 3D model.Finally,by integrating an engineering case study,the K0 value is determined to be 8,with a matching accuracy between the two model datasets ranging from 0.0669 to 1.0373 mm.Therefore,compared with the modeling method utilizing K-medoids clustering algorithm,the new modeling method significantly enhances the computational efficiency,the accuracy of selecting the optimal number of feature points in 3D laser scanning,and the precision of the 3D model derived from UAV tilt photogrammetry.This method provides a research foundation for constructing mine slope model. 展开更多
关键词 Air-ground data fusion method Mini batch K-Medoids algorithm Ebow rule Optimal cluster number 3D laser scanning UAV tilt photogrammetry
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Three-dimensional(3D)parametric measurements of individual gravels in the Gobi region using point cloud technique
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作者 JING Xiangyu HUANG Weiyi KAN Jiangming 《Journal of Arid Land》 SCIE CSCD 2024年第4期500-517,共18页
Gobi spans a large area of China,surpassing the combined expanse of mobile dunes and semi-fixed dunes.Its presence significantly influences the movement of sand and dust.However,the complex origins and diverse materia... Gobi spans a large area of China,surpassing the combined expanse of mobile dunes and semi-fixed dunes.Its presence significantly influences the movement of sand and dust.However,the complex origins and diverse materials constituting the Gobi result in notable differences in saltation processes across various Gobi surfaces.It is challenging to describe these processes according to a uniform morphology.Therefore,it becomes imperative to articulate surface characteristics through parameters such as the three-dimensional(3D)size and shape of gravel.Collecting morphology information for Gobi gravels is essential for studying its genesis and sand saltation.To enhance the efficiency and information yield of gravel parameter measurements,this study conducted field experiments in the Gobi region across Dunhuang City,Guazhou County,and Yumen City(administrated by Jiuquan City),Gansu Province,China in March 2023.A research framework and methodology for measuring 3D parameters of gravel using point cloud were developed,alongside improved calculation formulas for 3D parameters including gravel grain size,volume,flatness,roundness,sphericity,and equivalent grain size.Leveraging multi-view geometry technology for 3D reconstruction allowed for establishing an optimal data acquisition scheme characterized by high point cloud reconstruction efficiency and clear quality.Additionally,the proposed methodology incorporated point cloud clustering,segmentation,and filtering techniques to isolate individual gravel point clouds.Advanced point cloud algorithms,including the Oriented Bounding Box(OBB),point cloud slicing method,and point cloud triangulation,were then deployed to calculate the 3D parameters of individual gravels.These systematic processes allow precise and detailed characterization of individual gravels.For gravel grain size and volume,the correlation coefficients between point cloud and manual measurements all exceeded 0.9000,confirming the feasibility of the proposed methodology for measuring 3D parameters of individual gravels.The proposed workflow yields accurate calculations of relevant parameters for Gobi gravels,providing essential data support for subsequent studies on Gobi environments. 展开更多
关键词 Gobi gravels three-dimensional(3D)parameters point cloud 3D reconstruction Random Sample Consensus(RANSAC)algorithm Density-Based Spatial Clustering of Applications with Noise(DBSCAN)
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基于改进ID3算法的非结构化大数据分类优化方法
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作者 唐锴令 郑皓 《吉林大学学报(信息科学版)》 CAS 2024年第5期894-900,共7页
针对非结构化大数据在分类过程中,由于其数据中存在大量的冗余数据,若不能及时清洗大数据中的冗余数据,会降低数据分类精度的问题,提出一种基于改进ID3(Iterative Dichotomiser 3)算法的非结构化大数据分类优化方法。该方法针对非结构... 针对非结构化大数据在分类过程中,由于其数据中存在大量的冗余数据,若不能及时清洗大数据中的冗余数据,会降低数据分类精度的问题,提出一种基于改进ID3(Iterative Dichotomiser 3)算法的非结构化大数据分类优化方法。该方法针对非结构化大数据集合中冗余数据多以及维度繁杂的问题,对数据进行清洗处理,并结合有监督辨识矩阵完成数据降维;根据数据降维结果,采用改进ID3算法建立用于数据分类的决策树分类模型,通过该模型对非结构化大数据进行分类处理,从而实现数据的精准分类。实验结果表明,使用该方法对非结构化大数据分类时,分类效果好,精度高。 展开更多
关键词 改进ID3算法 数据清洗 数据降维 非结构化大数据 数据分类方法
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Novel registration algorithm for 3-D images captured from multiple views of object surface
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作者 衡伟 《Journal of Southeast University(English Edition)》 EI CAS 2005年第4期411-413,共3页
A novel algorithm of 3-D surface image registration is proposed. It makes use of the array information of 3-D points and takes vector/vertex-like features as the basis of the matching. That array information of 3-D po... A novel algorithm of 3-D surface image registration is proposed. It makes use of the array information of 3-D points and takes vector/vertex-like features as the basis of the matching. That array information of 3-D points can be easily obtained when capturing original 3-D images. The iterative least-mean-squared (LMS) algorithm is applied to optimizing adaptively the transformation matrix parameters. These can effectively improve the registration performance and hurry up the matching process. Experimental results show that it can reach a good subjective impression on aligned 3-D images. Although the algorithm focuses primarily on the human head model, it can also be used for other objects with small modifications. 展开更多
关键词 image alignment 3-D image 3-D capture image registration iterative least-mean-squared algorithm
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