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Complex tree: the basic framework of protein-protein interaction networks
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作者 DaiChuan Ma YuanBo Diao +3 位作者 YiZhou Li YanZi Guo Jiang Wu MengLong Li 《Natural Science》 2010年第9期998-1004,共7页
In living cells, proteins are dynamically connec ted through biochemical reactions, so its functi onal features are properly encoded into protein protein interaction networks (PINs). Up to pres ent, many efforts have ... In living cells, proteins are dynamically connec ted through biochemical reactions, so its functi onal features are properly encoded into protein protein interaction networks (PINs). Up to pres ent, many efforts have been devoted to exploring the basic feature of PINs. However, it is still a challenging problem to explore a universal pr operty of PINs. Here we employed the complex networks theory to analyze the proteinprotein interactions from Database of Interacting Prot ein. Complex tree: the unique framework of PINs was revealed by three topological properties of the giant component of PINs (GCOP), including rightskewed degree distributions, relatively sm all clustering coefficients and short characteristic path lengths. Furthermore, we proposed a no nlinearly growth model: complex tree model to reflect the tree framework, the simulation resu lts of this model showed that GCOPs were well represented by our model, which could be help ful for understanding the treestructure: basic framework of PINs. Source code and binaries freely available for download at http://cic.scu. edu.cn/bioinformatics/STM/STM_code.rar. 展开更多
关键词 complex NETWORKS complex tree PINS MODEL SIMULATION
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Study on Curative Effect of Perforated Injection of Zinc-ammonia Complex on Rosette Disease of Fruit Tree
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作者 王满平 《Plant Diseases and Pests》 CAS 2011年第2期70-72,共3页
[ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old ... [ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old apple, pear, peach and grape trees as the materials, the author studied the absorption condition of these trees to six kinds of zinc substances and their security. The sealed curative effects of the injected zinc substances which were harmful and could be absorbed steadily by the fruit trees against rosette disease were studied. [ Result] The results of absorption condition and security experiments showed that only zinc-mmnonia complex could be absorbed steadily and safely throughout four seasons. When apple, pear, peach and grape trees affected by rosette disease were injected with zinc- ammonia complex, the leaves of those trees started to grow obviously after 10 d; the internodes of diseased branches elongated, the leaves turned bigger, and the ap- pearance of branches became normal after about 25 d. [ Conclusion] The curative effect of perforated injection of zinc-ammonia complex on fruit tree rosette disease was remarkable. The results also provided a new way for the cure of deficiency diseases of other trace elements. 展开更多
关键词 Fruit tree Zinc-ammonia complex Perforated injection Rosette disease
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Quantization-Based Robust Image Watermarking Using the Dual Tree Complex Wavelet Transform 被引量:4
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作者 LIU Jinhua SHE Kun 《China Communications》 SCIE CSCD 2010年第4期1-6,共6页
Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some are... Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal.This scheme is not robust against geometric distortions and may lead to poor fidelity in some areas of content.Thus,we proposed a quantization-based image watermarking in the dual tree complex wavelet domain.We took advantages of the dual tree complex wavelets (perfect reconstruction,approximate shift invariance,and directional selectivity).For the case of watermark detecting,the probability of false alarm and probability of false negative were exploited and verified by simulation.Experimental results demonstrate that the proposed method is robust against JPEG compression,additive white Gaussian noise (AWGN),and some kinds of geometric attacks such as scaling,rotation,etc. 展开更多
关键词 Image Watermarking Quantization IndexModulation Dual tree complex Wavelet Transform JPEG Compression
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A New Construction Method for the Dual Tree Complex Wavelet Based on Direction Sensitivity 被引量:1
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作者 WANG Hong-Xia CHEN Bo CHENG Li-Zhi 《自动化学报》 EI CSCD 北大核心 2006年第1期47-53,共7页
The conception of 'main direction' of multi-dimensional wavelet is established in this paper, and the capabilities of several classical complex wavelets for representing directional singularities are investiga... The conception of 'main direction' of multi-dimensional wavelet is established in this paper, and the capabilities of several classical complex wavelets for representing directional singularities are investigated based on their main directions. It is proved to be impossible to represent directional singularities optimally by a multi-resolution analysis (MRA) of L2(R2). Based on the above results, a new algorithm to construct Q-shift dual tree complex wavelet is proposed. By optimizing the main direction of parameterized wavelet filters, the difficulty in choosing stop-band frequency is overcome and the performances of the designed wavelet are improved too. Furthermore, results of image enhancement by various multi-scale methods are given, which show that the new designed Q-shift complex wavelet do offer significant improvement over the conventionally used wavelets. Direction sensitivity is an important index to the performance of 2D wavelets. 展开更多
关键词 复合微波 对偶树 图象增加 灵敏性
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A Dual Tree Complex Discrete Cosine Harmonic Wavelet Transform (ADCHWT) and Its Application to Signal/Image Denoising 被引量:3
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作者 M. Shivamurti S. V. Narasimhan 《Journal of Signal and Information Processing》 2011年第3期218-226,共9页
A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT ha... A new simple and efficient dual tree analytic wavelet transform based on Discrete Cosine Harmonic Wavelet Transform DCHWT (ADCHWT) has been proposed and is applied for signal and image denoising. The analytic DCHWT has been realized by applying DCHWT to the original signal and its Hilbert transform. The shift invariance and the envelope extraction properties of the ADCHWT have been found to be very effective in denoising speech and image signals, compared to that of DCHWT. 展开更多
关键词 ANALYTIC DISCRETE COSINE Harmonic WAVELET TRANSFORM ANALYTIC WAVELET TRANSFORM Dual tree complex WAVELET TRANSFORM DCT Shift Invariant WAVELET TRANSFORM WAVELET TRANSFORM Denoising
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Seismic signal analysis based on the dual-tree complex wavelet packet transform
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作者 XIE Zhou-min(谢周敏) WANG En-fu(王恩福) +2 位作者 ZHANG Guo-hong(张国宏) ZHAO Guo-cun(赵国存) CHEN Xu-geng(陈旭庚) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第z1期117-122,共6页
We tried to apply the dual-tree complex wavelet packet transform in seismic signal analysis. The complex wavelet packet transform (CWPT) combine the merits of real wavelet packet transform with that of complex contin... We tried to apply the dual-tree complex wavelet packet transform in seismic signal analysis. The complex wavelet packet transform (CWPT) combine the merits of real wavelet packet transform with that of complex continuous wavelet transform (CCWT). It can not only pick up the phase information of signal, but also produce better ″focal- izing″ function if it matches the phase spectrum of signals analyzed. We here described the dual-tree CWPT algo- rithm, and gave the examples of simulation and actual seismic signals analysis. As shown by our results, the dual-tree CWPT is a very effective method in analyzing seismic signals with non-linear phase. 展开更多
关键词 dual-tree complex wavelet packet transform instantaneous characteristics seismicsignalanalysis
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Image inpainting using complex 2-D dual-tree wavelet transform
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作者 YANG Jian-bin 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2011年第1期70-76,共7页
The dual-tree complex wavelet transform is a useful tool in signal and image process- ing. In this paper, we propose a dual-tree complex wavelet transform (CWT) based algorithm for image inpalnting problem. Our appr... The dual-tree complex wavelet transform is a useful tool in signal and image process- ing. In this paper, we propose a dual-tree complex wavelet transform (CWT) based algorithm for image inpalnting problem. Our approach is based on Cai, Chan, Shen and Shen's framelet-based algorithm. The complex wavelet transform outperforms the standard real wavelet transform in the sense of shift-invariance, directionality and anti-aliasing. Numerical results illustrate the good performance of our algorithm. 展开更多
关键词 Image inpainting dual-tree complex wavelet transform wavelet shrinkage method.
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Defects Recognition of 3D Braided Composite Based on Dual-Tree Complex Wavelet Packet Transform
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作者 贺晓丽 王瑞 《Journal of Donghua University(English Edition)》 EI CAS 2015年第5期749-752,共4页
Textile-reinforced composites,due to their excellent highstrength-to-low-mass ratio, provide promising alternatives to conventional structural materials in many high-tech sectors. 3D braided composites are a kind of a... Textile-reinforced composites,due to their excellent highstrength-to-low-mass ratio, provide promising alternatives to conventional structural materials in many high-tech sectors. 3D braided composites are a kind of advanced composites reinforced with 3D braided fabrics; the complex nature of 3D braided composites makes the evaluation of the quality of the product very difficult. In this investigation,a defect recognition platform for 3D braided composites evaluation was constructed based on dual-tree complex wavelet packet transform( DT-CWPT) and backpropagation( BP) neural networks. The defects in 3D braided composite materials were probed and detected by an ultrasonic sensing system. DT-CWPT method was used to analyze the ultrasonic scanning pulse signals,and the feature vectors of these signals were extracted into the BP neural networks as samples. The type of defects was identified and recognized with the characteristic ultrasonic wave spectra. The position of defects for the test samples can be determined at the same time. This method would have great potential to evaluate the quality of 3D braided composites. 展开更多
关键词 3D braided composite dual-tree complex wavelet packet transform(DT-CWPT) ultrasonic wave
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Automatic Sleep Spindle Detection with EEG Based on Complex Demodulation Method and Decision Tree Model
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作者 Jiabin Li Bei Wang +2 位作者 Takenao Sugi Yu Zhang Masatoshi Nakamura 《Journal of Biomedical Science and Engineering》 2017年第5期10-17,共8页
Sleep spindle is the characteristic waveform of electroencephalogram (EEG) which is important for clinical diagnosis. In this study, an automatic sleep spindle detection method was developed. The EEG signals were reco... Sleep spindle is the characteristic waveform of electroencephalogram (EEG) which is important for clinical diagnosis. In this study, an automatic sleep spindle detection method was developed. The EEG signals were recorded based on the standard polysomnogram (PSG) measurement. A preprocessing procedure is introduced to exclude the unnecessary data segments and normalized the necessary data segments. Complex demodulation method is adopted to detect the candidate sleep spindle waveforms and calculate the features. The sleep spindles are recognized based on a decision tree model. Finally, the detected sleep spindles were utilized to amend the sleep stage recognition results. The sleep EEG data from 3 patients with sleep disorders were analyzed. The obtained results showed that the detected sleep spindles in EEG signal improved the accuracy of sleep stage recognition. 展开更多
关键词 SLEEP SPINDLE DETECTION complex DEMODULATION Method Decision tree Mod-el EEG
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基于强化双树复小波包变换的风电机组偏航轴承损伤识别 被引量:2
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作者 王晓龙 金韩微 +3 位作者 张博文 石海超 杨秀彬 何玉灵 《动力工程学报》 北大核心 2025年第1期115-123,共9页
针对风电机组偏航轴承损伤识别问题,提出了基于强化双树复小波包变换的损伤识别方法。首先,通过双树复小波包变换与线性峭度结合对不同分解层数下的分量计算平均线性峭度值,确定最优分解层数;其次,对最优分解所得小波系数及尺度系数进... 针对风电机组偏航轴承损伤识别问题,提出了基于强化双树复小波包变换的损伤识别方法。首先,通过双树复小波包变换与线性峭度结合对不同分解层数下的分量计算平均线性峭度值,确定最优分解层数;其次,对最优分解所得小波系数及尺度系数进行幅值调制,进而增强不同信号成分的能量;然后,采用散布熵指标确定各分量最佳调制系数并通过双树复小波包逆变换得到修正信号;最后,对修正信号作归一化平方包络谱分析提取故障特征频率。结果表明:所提方法能够实现复杂工况下偏航轴承损伤类型的准确识别,具有一定工程参考价值。 展开更多
关键词 风电机组 偏航轴承 双树复小波包变换 谱幅值调制
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基于复杂网络的洪涝灾害链风险评估 被引量:5
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作者 高玉琴 徐诺 +2 位作者 汪键 王丽君 刘彤 《水资源保护》 北大核心 2025年第2期115-122,共8页
为研究洪涝灾害演化过程对流域居民生活和社会经济的影响,从灾害链和复杂网络视角对洪涝灾害链演化风险开展评估。通过收集洪涝灾害典型案例,结合事件树分析法,搭建了洪涝灾害链演化网络。基于贝叶斯网络和网络传播模型,构建了洪涝灾害... 为研究洪涝灾害演化过程对流域居民生活和社会经济的影响,从灾害链和复杂网络视角对洪涝灾害链演化风险开展评估。通过收集洪涝灾害典型案例,结合事件树分析法,搭建了洪涝灾害链演化网络。基于贝叶斯网络和网络传播模型,构建了洪涝灾害链风险评估模型,并应用于秦淮河流域。结果表明:洪涝灾害链综合风险由节点风险累积或叠加构成;秦淮河流域“2016·7”洪涝灾害链综合风险水平在洪涝灾害发生后约103 h达极大值,约173 h达第二峰值,综合风险水平约为原生洪涝风险的7倍;公路事故、供排水事故、生态环境破坏事故、水污染事故为关键节点,洪涝灾害→水土流失灾害→水污染事故→生态环境破坏事故为关键传播边,通过对关键节点加强监测应对,对关键链条进行阻截断链,可有效减灾降损。 展开更多
关键词 洪涝灾害 灾害链 复杂网络 事件树分析法 贝叶斯网络 秦淮河流域
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基于双树复小波变换与稀疏表示的牙隐裂OCT三维图像融合 被引量:2
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作者 石博雅 董潇阳 《天津工业大学学报》 北大核心 2025年第1期62-68,共7页
针对采用光学相干层析(OCT)技术进行体积较大的前磨牙和磨牙的隐裂检测时,仅从单一扫描视角采集可能存在误检或漏检的问题,提出一种双树复小波变换(DTCWT)与稀疏表示(SR)相结合的牙隐裂三维图像融合方法。利用扫频OCT对人工牙隐裂模型从... 针对采用光学相干层析(OCT)技术进行体积较大的前磨牙和磨牙的隐裂检测时,仅从单一扫描视角采集可能存在误检或漏检的问题,提出一种双树复小波变换(DTCWT)与稀疏表示(SR)相结合的牙隐裂三维图像融合方法。利用扫频OCT对人工牙隐裂模型从2个扫描视角进行成像,经过三维图像配准后,利用双树复小波变换对图像进行分解。对于低频子带进行稀疏表示,采用“最大L1范数”规则进行融合,高频子带采用“绝对最大”规则融合,最后通过DTCWT重构得到融合后的图像。实验结果表明:采用本文方法融合后的牙隐裂图像可以得到裂纹的完整信息,获得准确的定位和分级,各方面性能均优于单独采用各多尺度分解方法和稀疏表示方法,标准差(SD)、平均梯度(AG)、空间频率(SF)和边缘信息评价因子(Q)的值分别平均提高到36.7、6.0、27.9和0.74,有效提高了OCT牙隐裂检测的准确性。 展开更多
关键词 牙隐裂 光学相干层析 稀疏表示 双树复小波变换
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基于优化VMD-DTCWT的局放信号去噪方法
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作者 伍忠东 王鹏波 +2 位作者 汤春阳 郑礼 苟敬聪 《兰州交通大学学报》 2025年第5期42-49,57,共9页
变压器局部放电检测是评估绝缘状态和预防故障的重要手段,但现场采集的变压器局部放电信号易受到背景噪声影响,需要通过去噪处理获取纯净信号。为此,提出一种基于改进VMD-DTCWT的局放信号去噪的方法。该方法基于峭度值准则采用改进的VM... 变压器局部放电检测是评估绝缘状态和预防故障的重要手段,但现场采集的变压器局部放电信号易受到背景噪声影响,需要通过去噪处理获取纯净信号。为此,提出一种基于改进VMD-DTCWT的局放信号去噪的方法。该方法基于峭度值准则采用改进的VMD算法初步去除了背景噪声中的窄带干扰噪声,其次通过使用美洲狮算法优化块阈值参数,进行双树复小波块阈值去噪,有效抑制白噪声干扰信号,最后使用自适应滤波器对背景噪声中的残余窄带干扰噪声进行滤除。实验结果表明,与传统去噪算法相比,提出的方法可以更有效地抑制噪声,使波形相似度系数在去除噪声后提高3%左右,更好地保留了局部放电信号的波形特征。 展开更多
关键词 局部放电 VMD 双树复小波 美洲狮算法 阈值块
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基于图复杂度引导机械臂路径裁剪的RRT算法
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作者 沈丹峰 姬晨辉 +1 位作者 赵刚 孙海涛 《西安工程大学学报》 2025年第4期26-36,共11页
针对快速搜索随机树(rapidly-exploring random tree,RRT)算法的随机采样特征导致的收敛速度慢、路径冗余度高、采样点利用率低问题,给出一种新的解决方法。首先,根据图复杂度公式,计算出图的复杂度后确定目标偏执概率,建立偏置概率自... 针对快速搜索随机树(rapidly-exploring random tree,RRT)算法的随机采样特征导致的收敛速度慢、路径冗余度高、采样点利用率低问题,给出一种新的解决方法。首先,根据图复杂度公式,计算出图的复杂度后确定目标偏执概率,建立偏置概率自适应模型;其次,在首次规划好路线后,路径中仍存在一些不必要的拐点与棱角,针对传统路径裁剪依赖局部搜索策略,可能导致次优解生成,提出PRM-Dijkstra(probabilistic roadmap-dijkstra)算法对路径进行裁剪,将改进RRT算法生成的树节点利用PRM算法相互连接起来,通过Dijkstra算法计算出一条最优路径;最后,改进RRT算法与PRM-Dijkstra种算法优势相结合,在保证有一条路径的前提下,最大概率的寻找最优路径。通过复杂图下仿真避障实验,结果显示:改进RRT算法在节点生成数量与规划用时相较传统RRT算法平均减少80%,相较于Goal-bias RRT算法均减少40%。并通过机器人操作系统(robot operating system,ROS)下的MoveIt!集成开发平台进行现实环境下避障实验,验证了算法的可行性与有效性。 展开更多
关键词 快速搜索随机树(RRT)算法 图复杂度 目标偏置 PRM-Dijkstra 机器人操作系统(ROS) 最优路径
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基于共振解调新方法的滚动轴承故障诊断
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作者 冯思茜 王家序 +1 位作者 张新 黄欣玥 《中国机械工程》 北大核心 2025年第9期2022-2031,共10页
为实现滚动轴承微弱特征提取与故障诊断,提出了一种基于子带重构重排-双树复小波包变换(SRR-DTCWPT)与峰值频率提取的共振解调新方法。基于SRR-DTCWPT的频带划分方法较为精细,并且在保持DTCWPT近似平移不变性和谱能量泄漏少的优点的同... 为实现滚动轴承微弱特征提取与故障诊断,提出了一种基于子带重构重排-双树复小波包变换(SRR-DTCWPT)与峰值频率提取的共振解调新方法。基于SRR-DTCWPT的频带划分方法较为精细,并且在保持DTCWPT近似平移不变性和谱能量泄漏少的优点的同时解决了频带错乱的问题。基于SRR-DTCWPT与峰值频率提取的共振解调方法不需要任何指标参与,能提取任意位置的频带,避免了强冲击干扰的影响,且计算过程自动化。将所提方法与Fast Kurtogram和Autogram算法进行比较,验证了该方法在滚动轴承故障诊断中的有效性与高效性。 展开更多
关键词 轴承故障诊断 共振解调 双树复小波包变换 子带重构重排 峰值频率提取
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基于双树复小波包变换的机械零件激光超声损伤信号增强方法
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作者 王燕萍 易茜 汤华 《激光杂志》 北大核心 2025年第8期82-88,共7页
机械零件的损伤检测对于保障机械设备的安全稳定运行至关重要。针对因多种因素影响导致机械零件激光超声损伤信号特征模糊的问题,提出基于双树复小波包变换的机械零件激光超声损伤信号增强方法。采集机械零件激光超声信号,采用自适应策... 机械零件的损伤检测对于保障机械设备的安全稳定运行至关重要。针对因多种因素影响导致机械零件激光超声损伤信号特征模糊的问题,提出基于双树复小波包变换的机械零件激光超声损伤信号增强方法。采集机械零件激光超声信号,采用自适应策略择取恰当的频带和频谱推算激光超声信号能量,通过双树复小波包变换提取激光超声损伤信号特征。根据提取到的信号特征运用可变模态分解得到信号低频段模态函数,利用剩余分量重构方法实现机械零件激光超声损伤信号增强。实验结果表明,所提方法处理后的信号波形不仅很好地抑制了噪声干扰,且最大程度保留了信号中的有用信息,对数谱距离在1.2~1.7之间变化,信源失真率在2.1%~3.1%之间变化,增强后信号峰值信噪比最大值为41.35 dB,波形保真度均值为0.86,信号增强效果好。 展开更多
关键词 双树复小波包变换 机械零件 激光超声 损伤信号增强 可变模态分解
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计算 3-Tree 网络全终端可靠度的线性时间算法
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作者 孙艳蕊 张祥德 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 1998年第4期439-441,共3页
对于一般网络,计算全终端可靠度是NP难问题.3Tree网络是一类具有特殊结构和性质的网络.利用三角子图到K4的化简,给出了一个计算3Tree网络全终端可靠度的线性时间算法.
关键词 3-tree网络 可靠度 复杂性 线性时间算法
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基于iTransformer-KAN和DTW的给水泵双重故障预警研究
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作者 黄俊清 茅大钧 《热能动力工程》 北大核心 2025年第3期171-184,共14页
基于当前火电厂中汽动给水泵普遍采用单预警模型,存在误报、漏报的风险,导致给水泵发生故障,进而严重影响汽水系统安全运行的问题,提出了一种双重故障预警的健康度评价模型。首先,利用斯皮尔曼(Spearman)相关性分析筛选相关的特征参数... 基于当前火电厂中汽动给水泵普遍采用单预警模型,存在误报、漏报的风险,导致给水泵发生故障,进而严重影响汽水系统安全运行的问题,提出了一种双重故障预警的健康度评价模型。首先,利用斯皮尔曼(Spearman)相关性分析筛选相关的特征参数作为输入,并通过双树复小波包变换(DTCWPT)对给水泵振动数据进行降噪处理,以提高输入数据的质量。其次,改进iTransformer模型,构建iTransformer-KAN故障预警模型,对给水泵驱动端轴承温度进行预测。最后,基于朗肯循环确定给水泵的核心故障监测参数,并利用时间动态规整(DTW)映射出期望给水流量与实际出口流量的偏离度。在计算预测残差值和实时偏离度值的基础上,采用核密度估计法(KDE)设定阈值,实现故障预警功能;同时,为便于运行人员做出决策,构建健康指数指标,可直观地展现给水泵的运行状态和机组状态等级的变化。实验结果表明:所提方法在实际数据中表现优异,预测模型的均方根误差为0.13,决定系数为0.997,预警效果优于其他对比模型;DTW监测模型可提前4.58 h提供维护建议,能够有效评估给水泵的运行状态,保障机组安全运行。 展开更多
关键词 故障预警 汽动给水泵 双树复小波包 注意力机制 深度学习
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融合节点动态传播特征与局域结构的复杂网络传播关键节点识别
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作者 侯诗雨 刘影 唐明 《物理学报》 北大核心 2025年第10期353-366,共14页
识别复杂网络中的传播关键节点在加速信息扩散、抑制病毒或谣言的传播等应用中至关重要.现有识别网络传播中关键节点的方法各有局限:复杂网络中心性方法仅从局域或者全局拓扑结构预测节点影响力;传统机器学习和深度学习方法不适用于图... 识别复杂网络中的传播关键节点在加速信息扩散、抑制病毒或谣言的传播等应用中至关重要.现有识别网络传播中关键节点的方法各有局限:复杂网络中心性方法仅从局域或者全局拓扑结构预测节点影响力;传统机器学习和深度学习方法不适用于图结构数据;已有基于图神经网络的方法忽视了传播过程自身的动力学特性.鉴于此,本文提出一种融合传播过程动力学特征与节点局域结构的传播动态图神经网络(propagation dynamics graph neural network,PDGNN),用于识别复杂网络传播中的关键节点.通过结合易感-感染-恢复传播模型,提取节点传播过程中的动态感染特征,构建高维特征向量并设计优化的损失函数,以实现对复杂网络传播关键节点的准确识别.在2个合成网络和7个真实网络上的实验结果表明,PDGNN在复杂网络传播关键节点识别准确性上优于经典的中心性方法、基于传统机器学习和深度学习的方法以及现有的基于图神经网络的方法. 展开更多
关键词 复杂网络 关键节点 图神经网络 局部传播树
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ViT-Count:面向冠层遮挡的Vision Transformer树木计数定位方法
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作者 张乔一 张瑞 霍光煜 《北京林业大学学报》 北大核心 2025年第10期128-138,共11页
【目的】针对复杂场景中树木检测的挑战,如遮挡、背景干扰及密集分布等,本研究提出一种基于Vision Transformer(ViT)的树木检测方法(ViT-Count),提升模型对复杂场景中树木的检测精度与鲁棒性。【方法】采用ViT作为基础模型,其在捕捉图... 【目的】针对复杂场景中树木检测的挑战,如遮挡、背景干扰及密集分布等,本研究提出一种基于Vision Transformer(ViT)的树木检测方法(ViT-Count),提升模型对复杂场景中树木的检测精度与鲁棒性。【方法】采用ViT作为基础模型,其在捕捉图像中全局上下文信息方面具有天然优势,尤其适用于形态多变的复杂环境。设计针对树木的视觉提示调优VPT机制,其通过在特征中注入可学习提示(prompts),优化模型在林地高密度树冠、光照变化及不同树种结构下的特征提取能力,提高对不同林分类型的适应性。设计卷积模块的注意力机制模块,利用其在局部感知基础上的长距离依赖建模能力,有效强化模型对树木遮挡、重叠及形态相似目标的辨别能力,提高整体检测的鲁棒性与准确性。设计一个树木检测解码器,通过多层卷积、归一化、GELU激活与上采样操作逐步还原空间分辨率,以生成的目标密度图实现树木计数与定位。【结果】该方法在提升森林、城市场景下的树木检测鲁棒性的同时,增强了模型在多尺度树木目标上的泛化能力。在Larch Casebearer数据集和Urban Tree数据集上进行的实验显示,与其他主流模型相比,该方法的MAE和RMSE最多分别降低了2.53、3.99,表明其泛化能力更强,具有最优的树木检测性能。可视化实验结果表明,在密集森林场景和复杂城市场景中,所提模型均具有较高的树木检测准确率。消融实验的结果证明了模型主要模块的有效性。【结论】基于Vision Transformer的面向复杂场景的树木计数与定位方法能够充分发挥ViT的全局建模能力及视觉提示调优机制任务适应性,结合卷积模块的注意力机制,有效提升复杂场景树木计数与定位的精度与鲁棒性。 展开更多
关键词 目标识别 树木计数 树木定位 复杂场景 Vision Transformer(ViT) 视觉提示调优(VPT) 注意力机制
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