期刊文献+
共找到12,387篇文章
< 1 2 250 >
每页显示 20 50 100
Vectorial Digitelligent Optics for High-Resolution Non-Line-of-Sight Imaging
1
作者 Yinghui Guo Yunsong Lei +8 位作者 Mingbo Pu Fei Zhang Qi Zhang Xiaoyin Li Runzhe Zhang Zhibin Zhao Rui Zhou Yulong Fan Xiangang Luo 《Engineering》 2025年第2期70-78,共9页
Object imaging beyond the direct line of sight is significant for applications in robotic vision,remote sensing,autonomous driving,and many other areas.Reconstruction of a non-line-of-sight(NLOS)screen is a complex in... Object imaging beyond the direct line of sight is significant for applications in robotic vision,remote sensing,autonomous driving,and many other areas.Reconstruction of a non-line-of-sight(NLOS)screen is a complex inverse problem that comes with ultrafast time-resolved imager requirements and substantial computational demands to extract information from the multi-bounce scattered light.Consequently,the echo signal always suffers from serious deterioration in both intensity and shape,leading to limited resolution and image contrast.Here,we propose a concept of vectorial digitelligent optics for high-resolution NLOS imaging to cancel the wall’s scattering and refocus the light onto hidden targets for enhanced echo.In this approach,the polarization and wavefront of the laser spot are intelligently optimized via a feedback algorithm to form a near-perfect focusing pattern through a random scattering wall.By raster scanning the focusing spot across the object’s surface within the optical-memory-effect range of the wall,we obtain nearly diffraction-limited NLOS imaging with an enhanced signal-to-noise ratio.Our experimental results demonstrate a resolution of 0.40 mm at a distance of 0.35 m,reaching the diffraction limit of the system.Furthermore,we demonstrate that the proposed method is feasible for various complex NLOS scenarios.Our methods may open an avenue for active imaging,communication,and laser wireless power transfer. 展开更多
关键词 Non-line-of-sight imaging Vectorial digitelligent optics Spatial light modulator Digital optics Wavefront shaping Metasurface
在线阅读 下载PDF
NIR-II biomedical optics:evolution and prospects from technological advances towards clinical translation
2
作者 LI Yi-Xuan XIA Qi-Ming +9 位作者 CHEN Guo-Qiao ZHANG Yi-Yin LIU Xiao-Long Adam Sofia Abdulkadir JIN Sheng-Xi ZHOU Feng-Bin LIN Deng-Feng QIAN Jun FAN Xiao-Xiao LIN Hui 《红外与毫米波学报》 北大核心 2025年第5期801-818,共18页
The second near-infrared window(NIR-II,900-1880 nm)overcomes critical limitations of visible(360-760 nm)and NIR-I(760-900 nm)imaging—including restricted penetration depth,low signal-to-back⁃ground ratio,and tissue a... The second near-infrared window(NIR-II,900-1880 nm)overcomes critical limitations of visible(360-760 nm)and NIR-I(760-900 nm)imaging—including restricted penetration depth,low signal-to-back⁃ground ratio,and tissue autofluorescence—establishing its pivotal role for in vivo deep-tissue bioimaging.With exponential growth in NIR-II photodiagnosis and phototherapy research over the past decade,bibliometric analy⁃sis is essential to map the evolving landscape and guide strategic priorities.We systematically analyzed 2,491 NIR-II-related publications(2009-2023)from the Web of Science Core Collection,employing scientometric tools for distinct analytical purposes:(a)VOSviewer,SCImago Graphica,and Gephi for co-authorship and co-occur⁃rence network mapping;(b)the R bibliometrix package for tracking field evolution and identifying high-impact publications/journals.The search retrieved 2491 studies from 359 journals originating from 54 countries.The country with the most published articles is China.Chinese institutions drive>60%of publications,with Stanford University(USA)and Nanyang Technological University(Singapore)ranked as the top two institutions by re⁃search quality.International cooperation is becoming increasingly frequent.Fan Quli,Tang Benzhong and Dai Hongjie are the top 3 productive authors in this field.Keyword evolution identifies"photodynamic therapy"and"immunotherapy"as pivotal future directions.We summarize the most cited literatures and NIR-II imaging clini⁃cal trials.This study delineates the NIR-II research trajectory,highlighting China's leadership,intensifying glob⁃al collaboration,and interdisciplinary convergence.Future efforts should prioritize the novel NIR-II probe devel⁃opment for NIR-II imaging and clinical translation of photodynamic/immunotherapy combinational platforms. 展开更多
关键词 second near-infrared window(NIR-II) biomedical optics clinical translation research trend
在线阅读 下载PDF
“The Eye is a Darke Roome”:Hobbes’Cartesian Optics
3
作者 Ofer Gal Victor Boantza 《自然辩证法通讯》 北大核心 2025年第5期50-68,共19页
I shall deserve the Reputation of having beene ye first to lay the grounds of two Sciences,"wrote Thomas Hobbes in 1646,"this of Optiques and yt other of natural Justice."For him,optics and politics wer... I shall deserve the Reputation of having beene ye first to lay the grounds of two Sciences,"wrote Thomas Hobbes in 1646,"this of Optiques and yt other of natural Justice."For him,optics and politics were two prongs of the same effort:to naturalize humans’relations to their world and to each other.It was Descartes’Dioptrique,handed to him by Kenelm Digby in 1637,that cleared for him the path:naturalizing humans required physicalizing vision–as Kepler taught in his own optics–and removing from nature of all cognitive entities such as"species visible and intelligible."Between 1639 and 1646 Hobbes produced three professional,innovative treatises on optics founded upon"the opinion of the excellent Monsieur Des Cartes"but,finally,diverging from it in the most crucial point.For Descartes,ridding"Matter[of all]such Descriptions…as belong but to Spiritual Beings"required a spiritual,non-material entity to interpret the physical effects of the senses.Hobbes,however,insisted that the interpretation can and should be understood physically and mechanically,for"Vision is the judgement itself. 展开更多
关键词 Thomas Hobbes RenéDescartes Kenelm Digby Thomas White Walter Warner optics early modern Epistemology Early modern Camera Obscura History
原文传递
Reduction of photoreceptor cell packing density in low or moderative myopia detected with adaptive optics scanning laser ophthalmoscopy
4
作者 Lin-Yi Lei Yue Zhao +2 位作者 Tang-Ren Cai Si-Guo Feng Jin Yao 《International Journal of Ophthalmology(English edition)》 2025年第4期683-690,共8页
AIM:To assess the variations in photoreceptor cell packing density(PCPD)across the retina among young healthy individuals with emmetropia,low and moderate myopia.METHODS:High-resolution adaptive optics scanning laser ... AIM:To assess the variations in photoreceptor cell packing density(PCPD)across the retina among young healthy individuals with emmetropia,low and moderate myopia.METHODS:High-resolution adaptive optics scanning laser ophthalmoscopy(AOSLO)systems were utilized for retinal imaging with a large sampling window of 700μm×700μm.The study cohort included 14 emmetropic[spherical equivalent(SE)ranged+0.5 to-0.5 D],15 low myopic(SE ranged-0.5 to-3 D)and 21 moderate myopic(SE ranged-3 to-6 D)healthy young adults.Photoreceptors at 3°temporal,6°superior and inferior 6°were captured.Statistical analysis was then performed to obtain PCPD and cell spacing.RESULTS:The average age of participants was 22.54±2.86(ranged 20–30y)with no difference among 3 groups.At 3°temporal,the emmetropic group exhibited the highest PCPD of 15186.16±2050.54 cells/mm^(2),while the low and moderate myopic groups had PCPD of 14009.15±1073.01 and 13466.92±1121.71 cells/mm2,respectively.At 3°temporal,the emmetropic group also had the smallest cell spacing at 6.66±0.26 mm,compared to 6.85±0.26 and 6.91±0.28 mm for the low and moderate myopic groups,respectively.Compared to the emmetropic group,at 3°temporal,the myopic groups showed significantly reduced PCPD(low myopia:P=0.032;moderate myopia:P=0.001).At 6°inferior,the moderate myopic group exhibited a significant decrease in PCPD(P=0.013),while at 6°superior,there were no significant statistical differences in PCPD for the low and moderate myopic groups(P>0.05).In comparison to the emmetropic group,only the moderate myopic group showed significantly increased cell spacing at all three positions(temporal 3°:P=0.011,superior 6°:P=0.046,inferior 6°:P=0.013).Correlation analysis revealed a positive correlation between PCPD and axial length changes(P<0.05).CONCLUSION:Reduced PCPD and increased cell spacing strongly correlated with refractive error in mild to moderate myopic eyes,especially at 6°inferior to the fovea and the decreased PCPD in the macular region of myopic patients may be associated with increased axial lengthinduced retinal stretching. 展开更多
关键词 adaptive optics scanning laser ophthalmoscopy photoreceptor cell packing density FOVEA refractive error MYOPIA
原文传递
Editorial for the Special Issue on Subwavelength Optics
5
作者 Xiangang Luo Jinghua Teng Mingbo Pu 《Engineering》 2025年第2期1-2,共2页
The field of subwavelength optics has opened new avenues for investigating light–matter interactions by enabling the exploration of novel phenomena at the subwavelength scale. In recent decades,advancements in fundam... The field of subwavelength optics has opened new avenues for investigating light–matter interactions by enabling the exploration of novel phenomena at the subwavelength scale. In recent decades,advancements in fundamental understanding and micro–nanotechnologies have significantly propelled the development of subwavelength optics and its practical applications. 展开更多
关键词 subwavelength optics micro nanotechnologies light matter interactions practical applications
在线阅读 下载PDF
Retained imaging quality with reduced manufacturing precision:leveraging computational optics
6
作者 Yujie Xing Xiong Dun +6 位作者 Dinghao Yang Siyu Dong Yifan Peng Xuquan Wang Jun Yu Zhanshan Wang Xinbin Cheng 《Advanced Photonics Nexus》 2025年第4期128-139,共12页
Manufacturing-robust imaging systems leveraging computational optics hold immense potential for easing manufacturing constraints and enabling the development of cost-effective,high-quality imaging solutions.However,co... Manufacturing-robust imaging systems leveraging computational optics hold immense potential for easing manufacturing constraints and enabling the development of cost-effective,high-quality imaging solutions.However,conventional approaches,which typically rely on data-driven neural networks to correct optical aberrations caused by manufacturing errors,are constrained by the lack of effective tolerance analysis methods for quantitatively evaluating manufacturing error boundaries.This limitation is crucial for further relaxing manufacturing constraints and providing practical guidance for fabrication.We propose a physics-informed design paradigm for manufacturing-robust imaging systems with computational optics,integrating a physics-informed tolerance analysis methodology for evaluating manufacturing error boundaries and a physics-informed neural network for image reconstruction.With this approach,we achieve a manufacturing-robust imaging system based on an off-axis three-mirror freeform all-aluminum design,delivering a modulation transfer function exceeding 0.34 at the Nyquist frequency(72 lp/mm)in simulation.Notably,this system requires a manufacturing precision of only 0.5λin root mean square(RMS),representing a remarkable 25-fold relaxation compared with the conventional requirement of 0.02λin RMS.Experimental validation further confirmed that the manufacturing-robust imaging system maintains excellent performance in diverse indoor and outdoor environments.Our proposed method paves the way for achieving high-quality imaging without the necessity of high manufacturing precision,enabling practical solutions that are more cost-effective and time-efficient. 展开更多
关键词 manufacturing-robust imaging system computational optics physics-informed tolerance analysis physics-informed neural network
在线阅读 下载PDF
Embedded solar adaptive optics telescope:achieving compact integration for high-efficiency solar observations
7
作者 Naiting Gu Hao Chen +11 位作者 Ao Tang Xinlong Fan Carlos Quintero Noda Yawei Xiao Libo Zhong Xiaosong Wu Zhenyu Zhang Yanrong Yang Zao Yi Xiaohu Wu Linhai Huang Changhui Rao 《Opto-Electronic Advances》 2025年第5期60-74,共15页
Adaptive optics(AO)has significantly advanced high-resolution solar observations by mitigating atmospheric turbulence.However,traditional post-focal AO systems suffer from external configurations that introduce excess... Adaptive optics(AO)has significantly advanced high-resolution solar observations by mitigating atmospheric turbulence.However,traditional post-focal AO systems suffer from external configurations that introduce excessive optical surfaces,reduced light throughput,and instrumental polarization.To address these limitations,we propose an embedded solar adaptive optics telescope(ESAOT)that intrinsically incorporates the solar AO(SAO)subsystem within the telescope's optical train,featuring a co-designed correction chain with a single Hartmann-Shack full-wavefront sensor(HS f-WFS)and a deformable secondary mirror(DSM).The HS f-WFS uses temporal-spatial hybrid sampling technique to simultane-ously resolve tip-tilt and high-order aberrations,while the DSM performs real-time compensation through adaptive modal optimization.This unified architecture achieves symmetrical polarization suppression and high system throughput by min-imizing optical surfaces.A 600 mm ESAOT prototype incorporating a 12×12 micro-lens array HS f-WFS and 61-actuator piezoelectric DSM has been developed and successfully conducted on-sky photospheric observations.Validations in-cluding turbulence simulations,optical bench testing,and practical observations at the Lijiang observatory collectively confirm the system's capability to maintain aboutλ/10 wavefront error during active region tracking.This architectural breakthrough of the ESAOT addresses long-standing SAO integration challenges in solar astronomy and provides scala-bility analyses confirming direct applicability to the existing and future large solar observation facilities. 展开更多
关键词 embedded solar adaptive optics telescope(ESAOT) Hartmann-Shack full-wavefront sensor(HS f-WFS) deformable secondary mirror(DSM) high-resolution solar observations solar telescopes
在线阅读 下载PDF
OPTICS算法在雷电临近预报中的应用 被引量:13
8
作者 侯荣涛 路郁 +2 位作者 王琴 袁程胜 王军 《计算机应用》 CSCD 北大核心 2014年第1期297-301,共5页
针对密度分布不均的雷电定位资料,提出了一种基于OPTICS聚类算法的雷电临近预警模型。该模型运用OPTICS算法对雷暴天气连续时段的雷电定位资料进行聚类分析,有效剔除了影响雷暴云分布的稀疏点。在聚类分析结果基础上,利用"膨胀-侵... 针对密度分布不均的雷电定位资料,提出了一种基于OPTICS聚类算法的雷电临近预警模型。该模型运用OPTICS算法对雷暴天气连续时段的雷电定位资料进行聚类分析,有效剔除了影响雷暴云分布的稀疏点。在聚类分析结果基础上,利用"膨胀-侵蚀"算法还原雷暴云真实分布,根据雷暴云的移动趋势进行雷电落区预报。此外,针对传统预测算法运行时间长的缺陷,运用邻接表改进了OPTICS算法,且优化了可达队列更新策略。实验结果表明,基于改进的OPTICS算法所构建的雷电临近预报模型降低了算法运行时间,同时提高了雷电预报模型适应能力及预测的准确率。 展开更多
关键词 雷电临近预报 定位资料 聚类分析 optics算法 移动趋势
在线阅读 下载PDF
一种基于网格与加权信息熵的OPTICS改进算法 被引量:11
9
作者 安建瑞 张龙波 +3 位作者 王雷 金超 怀浩 王晓丹 《计算机工程》 CAS CSCD 北大核心 2017年第2期206-209,共4页
针对现有OPTICS算法时间复杂度高且不适用于数据密集型环境的问题,提出一种基于网格与加权信息熵的改进算法。将数据集合划分为一定数量的网格单元,引入加权信息熵,自适应计算每个网格单元的最小密度阈值。对满足最小密度阈值的网格单... 针对现有OPTICS算法时间复杂度高且不适用于数据密集型环境的问题,提出一种基于网格与加权信息熵的改进算法。将数据集合划分为一定数量的网格单元,引入加权信息熵,自适应计算每个网格单元的最小密度阈值。对满足最小密度阈值的网格单元定义密集格的概念,利用质心点代替网格数据点集的方法对数据点进行压缩。采用Geolife Trajectories数据集对算法性能进行测试,从理论分析和实验结果两方面证明了改进算法的有效性。 展开更多
关键词 数据密集型环境 加权信息熵 optics算法 密度阈值 质心点
在线阅读 下载PDF
改进的OPTICS算法及其在文本聚类中的应用 被引量:29
10
作者 曾依灵 许洪波 白硕 《中文信息学报》 CSCD 北大核心 2008年第1期51-55,60,共6页
基于密度的OPTICS聚类算法以可视化的结果输出方式直观呈现语料结构,但由于其结果组织策略在处理稀疏点时的局限性,算法实际性能未能得到充分发挥。本文针对此缺陷提出一种有效的结果重组织策略以辅助稀疏点的重新定位,并针对文本领域... 基于密度的OPTICS聚类算法以可视化的结果输出方式直观呈现语料结构,但由于其结果组织策略在处理稀疏点时的局限性,算法实际性能未能得到充分发挥。本文针对此缺陷提出一种有效的结果重组织策略以辅助稀疏点的重新定位,并针对文本领域的特点改变距离度量方法,形成了OPTICS-Plus文本聚类算法。在真实文本分类语料上的实验表明,我们的结果重组织策略能够辅助算法产生更为清晰反映语料结构的可达图,与K-means算法的比较则证实了OPTICS-Plus具有较为良好的聚类性能。 展开更多
关键词 计算机应用 中文信息处理 optics算法 密度聚类 文本挖掘
在线阅读 下载PDF
AI-driven Fourier Ptychography and Its Insight for“AI+Optics”(Invited)
11
作者 PAN An WANG Aiye +4 位作者 FENG Tianci GAO Huiqin WANG Siyuan XU Jinghao LI Xuan 《光子学报》 北大核心 2025年第9期146-170,共25页
Fourier Ptychographic Microscopy(FPM)is a high-throughput computational optical imaging technology reported in 2013.It effectively breaks through the trade-off between high-resolution imaging and wide-field imaging.In... Fourier Ptychographic Microscopy(FPM)is a high-throughput computational optical imaging technology reported in 2013.It effectively breaks through the trade-off between high-resolution imaging and wide-field imaging.In recent years,it has been found that FPM is not only a tool to break through the trade-off between field of view and spatial resolution,but also a paradigm to break through those trade-off problems,thus attracting extensive attention.Compared with previous reviews,this review does not introduce its concept,basic principles,optical system and series of applications once again,but focuses on elaborating the three major difficulties faced by FPM technology in the process from“looking good”in the laboratory to“working well”in practical applications:mismatch between numerical model and physical reality,long reconstruction time and high computing power demand,and lack of multi-modal expansion.It introduces how to achieve key technological innovations in FPM through the dual drive of Artificial Intelligence(AI)and physics,including intelligent reconstruction algorithms introducing machine learning concepts,optical-algorithm co-design,fusion of frequency domain extrapolation methods and generative adversarial networks,multi-modal imaging schemes and data fusion enhancement,etc.,gradually solving the difficulties of FPM technology.Conversely,this review deeply considers the unique value of FPM technology in potentially feeding back to the development of“AI+optics”,such as providing AI benchmark tests under physical constraints,inspirations for the balance of computing power and bandwidth in miniaturized intelligent microscopes,and photoelectric hybrid architectures.Finally,it introduces the industrialization path and frontier directions of FPM technology,pointing out that with the promotion of the dual drive of AI and physics,it will generate a large number of industrial application case,and looks forward to the possibilities of future application scenarios and expansions,for instance,body fluid biopsy and point-of-care testing at the grassroots level represent the expansion of the growth market. 展开更多
关键词 Computational optical imaging Fourier ptychography Artificial Intelligence Highthroughput imaging Multimodal imaging
在线阅读 下载PDF
不确定NNSB-OPTICS聚类算法在滑坡危险性预测中的研究与应用 被引量:3
12
作者 毛伊敏 陈华彬 +1 位作者 李忠利 张灿龙 《计算机应用研究》 CSCD 北大核心 2019年第1期127-131,15,共6页
针对滑坡危险性预测中降雨等不确定因素不能有效刻画及处理和现有的OPTICS-PLUS聚类算法需要设置密度阈值、时间复杂度高等问题进行了研究,为了提高滑坡危险性预测准确率,提出一种不确定NNSB-OPTICS聚类算法并应用于滑坡预测中。首先对O... 针对滑坡危险性预测中降雨等不确定因素不能有效刻画及处理和现有的OPTICS-PLUS聚类算法需要设置密度阈值、时间复杂度高等问题进行了研究,为了提高滑坡危险性预测准确率,提出一种不确定NNSB-OPTICS聚类算法并应用于滑坡预测中。首先对OPTICS-PLUS算法扩张策略进行优化,避免了人工设置密度阈值,提高了算法效率;然后根据降雨量数据的分布特征,综合EW型距离公式和云模型理论,提出EC型距离公式,有效处理不确定数据降雨量;最后将不确定NNSB-OPTICS聚类算法应用于延安市宝塔区滑坡危险性预测中,建立滑坡危险性预测模型,滑坡预测精度达到89. 7%。实验结果表明,该方法能够有效提高滑坡危险性预测精度,具有较高的可行性。 展开更多
关键词 滑坡 危险性预测 不确定数据 optics算法
在线阅读 下载PDF
基于OPTICS的变电设备状态监测异常数据过滤算法 被引量:7
13
作者 张强 王序文 +2 位作者 王小捷 陈光 刘娟 《电力信息与通信技术》 2015年第6期8-14,共7页
针对变电一次设备状态监测中普遍存在的异常数据问题,提出了一种基于点排序识别聚类结构(Ordering Points to Identify the Clustering Structure,OPTICS)的状态监测异常数据过滤算法。通过对一次设备状态监测的历史数据进行异常数据特... 针对变电一次设备状态监测中普遍存在的异常数据问题,提出了一种基于点排序识别聚类结构(Ordering Points to Identify the Clustering Structure,OPTICS)的状态监测异常数据过滤算法。通过对一次设备状态监测的历史数据进行异常数据特征分析,建立了基于密度聚类的异常数据过滤机制。并以某110 k V变电站一次设备变压器油色谱以及GIS SF6密度微水实验为例,对该算法的异常数据检测效果进行了验证。该算法与传统异常数据过滤算法的对比试验结果表明,该算法能够准确地识别异常数据的特征,有效过滤状态监测中的异常数据,显著降低噪声干扰,从而提高数据的可靠性。 展开更多
关键词 异常数据 optics聚类 状态监测 数据挖掘
在线阅读 下载PDF
基于改进OPTICS算法的磁罗盘椭圆拟合误差补偿方法 被引量:5
14
作者 缪玲娟 吴子昊 +1 位作者 周志强 李正帅 《中国惯性技术学报》 EI CSCD 北大核心 2022年第2期174-180,共7页
为了避免磁罗盘原始数据中的奇异误差点对椭圆拟合精度造成不利影响,在常规最小二乘椭圆拟合算法中引入了基于密度聚类的OPTICS算法,并对OPTICS算法进行了改进,以降低复杂度,减小计算耗时。在椭圆拟合之前,使用改进的OPTICS算法对原始... 为了避免磁罗盘原始数据中的奇异误差点对椭圆拟合精度造成不利影响,在常规最小二乘椭圆拟合算法中引入了基于密度聚类的OPTICS算法,并对OPTICS算法进行了改进,以降低复杂度,减小计算耗时。在椭圆拟合之前,使用改进的OPTICS算法对原始传感器数据进行分类,识别并剔除数据中的奇异误差点,防止其污染原始数据集,提高椭圆拟合算法的拟合精度,从而提高航向角的解算精度。实验结果表明,与常规椭圆拟合算法相比,所提出的算法在东、南、西、北四个方向上合计航向角误差的均方根降低了27.5%,且改进后OPTICS算法的计算耗时比改进前降低了43.6%。 展开更多
关键词 磁罗盘 椭圆拟合 误差补偿 最小二乘法 optics算法
在线阅读 下载PDF
一种基于OPTICS聚类的流量分类算法 被引量:4
15
作者 张建伟 王玲艳 姚云磊 《郑州轻工业学院学报(自然科学版)》 CAS 2013年第2期83-86,共4页
提出了一种适合在线实时分类并避免过多人为因素干扰的流量分类方法.该方案早期采用DPI技术识别信息流的业务类型,作为后期聚类算法的指导和基准;借鉴OPTICS聚类算法思想,用数据点的个数来衡量稠密度,完成信息流的聚类,可有针对性地为... 提出了一种适合在线实时分类并避免过多人为因素干扰的流量分类方法.该方案早期采用DPI技术识别信息流的业务类型,作为后期聚类算法的指导和基准;借鉴OPTICS聚类算法思想,用数据点的个数来衡量稠密度,完成信息流的聚类,可有针对性地为用户提供服务. 展开更多
关键词 网络流量 流量识别 聚类算法 optics
在线阅读 下载PDF
基于OPTICS算法的变异体约简技术 被引量:1
16
作者 吕学伟 黄松 王晔 《解放军理工大学学报(自然科学版)》 EI 北大核心 2016年第2期101-104,共4页
为了降低变异测试的计算代价,提出了一种基于OPTICS算法的变异体约简方法。首先利用OPTICS算法对变异体进行聚类,让相似的变异体在同一类簇中,然后从每个类簇中随机选取一个变异体作为代表,与其余离散的变异体组成新的变异体集合,从而... 为了降低变异测试的计算代价,提出了一种基于OPTICS算法的变异体约简方法。首先利用OPTICS算法对变异体进行聚类,让相似的变异体在同一类簇中,然后从每个类簇中随机选取一个变异体作为代表,与其余离散的变异体组成新的变异体集合,从而达到约简变异体数量的目的。为了验证算法的效果,选择一组常用的被测程序进行实验,并和K-means算法进行比较。实验结果表明,该方法在不降低变异充分度的情况下取得了良好的约简效果,有效地减少了变异体的数量,从而降低了变异测试所产生的计算代价。 展开更多
关键词 optics算法 变异体约简 聚类技术
在线阅读 下载PDF
基于数据分区的OPTICS聚类算法 被引量:7
17
作者 周传华 鲁勇 于猜 《传感器与微系统》 CSCD 北大核心 2022年第10期103-107,共5页
针对OPTICS算法存在着对于密度不均匀以及高维数据聚类效果差的问题,提出了基于数据分区的OPTICS聚类算法(DP-OPTICS)。该方法计算所有样本点的K距离(K-dist)值,用改进的K均值算法对K-dist值进行单维度聚类,并依据肘图拐点的位置调整K... 针对OPTICS算法存在着对于密度不均匀以及高维数据聚类效果差的问题,提出了基于数据分区的OPTICS聚类算法(DP-OPTICS)。该方法计算所有样本点的K距离(K-dist)值,用改进的K均值算法对K-dist值进行单维度聚类,并依据肘图拐点的位置调整K值大小,以此实现数据分区;在分区内用OPTICS算法进行局部聚类,最后按一定规则将数据分区合并。选取多个不平衡人工数据集和UCI数据集进行对比实验,实验结果表明:改进的算法是切实可行的,明显提升了OPTICS算法对于数据密度不均匀问题的聚类质量,并且对高维数据也有着较好的处理能力,具有很强的鲁棒性。 展开更多
关键词 聚类 数据分区 optics算法 K距离
在线阅读 下载PDF
基于改进OPTICS聚类的雷达信号预分选方法 被引量:9
18
作者 吴连慧 周秀珍 宋新超 《舰船电子对抗》 2018年第6期95-99,共5页
针对DBSCAN算法不能分选密度分布不均雷达信号的缺陷,提出了一种基于改进OPTICS聚类的雷达信号预分选方法。利用OPTICS算法的核心距离和可达距离来实现对不同密度分布的雷达信号预分选。将雷达信号进行网格单元划分,并采用两级处理方式... 针对DBSCAN算法不能分选密度分布不均雷达信号的缺陷,提出了一种基于改进OPTICS聚类的雷达信号预分选方法。利用OPTICS算法的核心距离和可达距离来实现对不同密度分布的雷达信号预分选。将雷达信号进行网格单元划分,并采用两级处理方式,第一级处理高密度信号,第二级累积并处理低密度信号。实验结果表明,与传统的DBSCAN算法相比,改进OPTICS算法适用于不同密度分布的雷达信号,能够提高复杂体制雷达信号分选的正确率,同时降低了算法运行时间。 展开更多
关键词 雷达信号分选 预分选 optics算法 网格单元 两级处理
在线阅读 下载PDF
Active Optics in LAMOST 被引量:4
19
作者 Ding-QiangSu Xiang-QunCui 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2004年第1期1-9,共9页
Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is one of the major national projects under construction in China. Active optics is one of the most important technologies for new large telescopes. I... Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is one of the major national projects under construction in China. Active optics is one of the most important technologies for new large telescopes. It is used for correcting telescope errors generated by gravitational and thermal changes. Here, however, we use this technology to realize the configuration of LAMOST,—a task that cannot be done in the traditional way. A comprehensive and intensive research on the active optics used in LAMOST is also reported, including an open-loop control method and an auxiliary closed-loop control method. Another important development is in our pre-calibration method of open-loop control, which is with some new features: simultaneous calculation of the forces and displacements of force actuators and displacement actuators; the profile of mirror can be arbitrary; the mirror surface shape is not expressed by a fitting polynomial, but is derived from the mirror surface shape formula which is highly accurate; a proof is given that the solution of the pre-calibration method is the same as the least squares solution. 展开更多
关键词 galaxies: distances and redshifts techniques: active optics telescopes instrumentation: adaptive optics
在线阅读 下载PDF
使用均值距离与关联性标记的并行OPTICS算法 被引量:1
20
作者 郑剑 余鑫 《计算机工程与应用》 CSCD 北大核心 2023年第5期232-244,共13页
针对大数据环境下传统并行密度聚类算法中存在的数据划分不合理,聚类结果准确度不高,结果受参数影响较大以及并行效率低等问题,提出一种MapReduce下使用均值距离与关联性标记的并行OPTICS算法——POMDRM-MR。算法使用一种基于维度稀疏... 针对大数据环境下传统并行密度聚类算法中存在的数据划分不合理,聚类结果准确度不高,结果受参数影响较大以及并行效率低等问题,提出一种MapReduce下使用均值距离与关联性标记的并行OPTICS算法——POMDRM-MR。算法使用一种基于维度稀疏度的减少边界点划分策略(DS-PRBP),划分数据集;针对各个分区,提出标记点排序识别簇算法(MOPTICS),构建数据点与核心点之间的关联性,并标记数据点迭代次数,在距离度量中,使用领域均值距离策略(FMD),计算数据点的领域均值距离,代替可达距离排序,输出关联性标记序列;最后结合重排序序列提取簇算法(REC),对输出序列进行二次排序并提取簇,提高算法局部聚类的准确性和稳定性;在合并全局簇时,算法提出边界密度筛选策略(BD-FLC),计算筛选密度相近局部簇;又基于n叉树的并集型合并与MapReduce模型,提出并行局部簇合并算法(MCNT-MR),加快局部簇收敛,并行合并局部簇,提升全局簇合并效率。对照实验表明,POMDRM-MR算法聚类效果更佳,且在大规模数据集下算法的并行化性能更好。 展开更多
关键词 大数据 密度聚类 MAPREDUCE optics PRBP
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部