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Relationships between Rainy Days,Mean Daily Intensity and Seasonal Rainfall in Normal,Flood and Drought Years over India 被引量:1
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作者 C.V.Singh 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1998年第3期142-150,共9页
here are limitations in using the seasonal rainfall total in studies of Monsoon rainfall climatology. A correlation analysis of the individual station seasonal rainfall with all India seasonal mean rainfall has been m... here are limitations in using the seasonal rainfall total in studies of Monsoon rainfall climatology. A correlation analysis of the individual station seasonal rainfall with all India seasonal mean rainfall has been made. After taking the significance test (strictly up to 5% level) the stations which are significantly correlated have been considered in this study in normal, flood and drought years respectively. Analysis of seasonal rainfall data of 50 stations spread over a period of 41 years suggests that a linear relationship fits better than the logarithmic relationship when seasonal rainfall versus number of rainy days is studied. The linear relationship is also found to be better in the case of seasonal rainfall versus mean daily intensity. 展开更多
关键词 Monsoon rainfall Linear relationship Logarithmic relationship Mean daily rainfall intensity Seasonal rainfall
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基于CEEMDAN与自相关函数的心音去噪
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作者 唐瑭 卢官明 +2 位作者 戚继荣 王洋 赵宇航 《软件工程》 2025年第1期14-18,共5页
为有效去除心音信号中的噪声,提出基于CEEMDAN(Complete Ensemble Empirical Mode Decomposition with Adaptive Noise)与自相关函数的心音去噪算法。首先,通过CEEMDAN将含噪的心音信号分解为具有不同尺度特征的IMF(Intrinsic Mode Func... 为有效去除心音信号中的噪声,提出基于CEEMDAN(Complete Ensemble Empirical Mode Decomposition with Adaptive Noise)与自相关函数的心音去噪算法。首先,通过CEEMDAN将含噪的心音信号分解为具有不同尺度特征的IMF(Intrinsic Mode Function)分量;其次,根据噪声与心音的自相关函数性质不同,界定IMF分量的信噪分界点;最后,对以噪声为主的IMF分量进行均值滤波,并将其与以心音为主的IMF分量重构得到去噪后信号。实验表明,在不同的噪声水平下,与小波软阈值去噪算法、小波硬阈值去噪算法、CEEMDAN去噪算法相比,所提算法的信噪比最高,均方根误差最小,在去除噪声的同时,可以较好地保留心音信号中的有效信息。 展开更多
关键词 心音去噪 CEEMDAN 自相关函数 均值滤波
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Noise cancellation of a multi-reference full-wave magnetic resonance sounding signal based on a modified sigmoid variable step size least mean square algorithm 被引量:1
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作者 TIAN Bao-feng ZHOU Yuan-yuan +2 位作者 ZHU Hui JIANG Chuan-dong YI Xiao-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第4期900-911,共12页
Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characte... Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characteristic parameters and hindering effective inverse interpretation. Considering the complexity and non-homogeneous spatial distribution of environmental noise and based on the theory of adaptive noise cancellation, a model system for noise cancellation using multi-reference coils was constructed to receive MRS signals. The feasibility of this system with theoretical calculation and experiments was analyzed and a modified sigmoid variable step size least mean square(SVSLMS) algorithm for noise cancellation was presented. The simulation results show that, the multi-reference coil method performs better than the single one on both signal-to-noise ratio(SNR) improvement and signal waveform optimization after filtering, under the condition of different noise correlations in the reference coils and primary detecting coils and different SNRs. In particular, when the noise correlation is poor and the SNR<0, the SNR can be improved by more than 8 dB after filtering with multi-reference coils. And the average fitting errors for initial amplitude and relaxation time are within 5%. Compared with the normalized least mean square(NLMS) algorithm and multichannel Wiener filter and processing field test data, the effectiveness of the proposed method is verified. 展开更多
关键词 magnetic resonance soundING SIGNAL MULTI-REFERENCE coils adaptive noise CANCELLATION SIGMOID variable step size least mean SQUARE (SVSLMS)
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Theoretical relationship between sound velocity and the physical properties of submarine sediment 被引量:4
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作者 LONG Jianjun LI Ganxian 《Chinese Journal of Acoustics》 CSCD 2015年第4期401-412,共12页
Density and elastic modulus change ratios are introduced to describe the sound velocity of submarine sediment. The density change ratio is a composite parameter describing the sound velocity. It is expressed by three ... Density and elastic modulus change ratios are introduced to describe the sound velocity of submarine sediment. The density change ratio is a composite parameter describing the sound velocity. It is expressed by three physical parameters: porosity, solid phase density and seawater density. The elastic modulus change ratio is also a composite parameter of sound velocity. It is expressed by three physical parameters, including porosity, solid phase modulus and seawater bulk modulus. The sound velocity formula can be developed into a Taylor polyno- mial formula of these two composite parameters. The change in the two composite parameters constitutes the sound velocity surface, which contains the complete information regarding ve- locity properties and sediment characteristics. The one-parameter velocity formula is a curve on the velocity surface. Each porosity-velocity empirical formula, which represents various sea locations and conditions, is transformed to a standard form. This result is the product of a reference velocity and a modulation function. Comparisons of the numerical calculation and measurements show that the derived modulation functions yield similar results. The difference between the velocity formula derived in this paper and the Wood velocity formula is due to the elastic modulus models. 展开更多
关键词 Theoretical relationship between sound velocity and the physical properties of submarine sediment
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A combined algorithm of K-means and MTRL for multi-class classification 被引量:2
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作者 XUE Mengfan HAN Lei PENG Dongliang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第5期875-885,共11页
The basic idea of multi-class classification is a disassembly method,which is to decompose a multi-class classification task into several binary classification tasks.In order to improve the accuracy of multi-class cla... The basic idea of multi-class classification is a disassembly method,which is to decompose a multi-class classification task into several binary classification tasks.In order to improve the accuracy of multi-class classification in the case of insufficient samples,this paper proposes a multi-class classification method combining K-means and multi-task relationship learning(MTRL).The method first uses the split method of One vs.Rest to disassemble the multi-class classification task into binary classification tasks.K-means is used to down sample the dataset of each task,which can prevent over-fitting of the model while reducing training costs.Finally,the sampled dataset is applied to the MTRL,and multiple binary classifiers are trained together.With the help of MTRL,this method can utilize the inter-task association to train the model,and achieve the purpose of improving the classification accuracy of each binary classifier.The effectiveness of the proposed approach is demonstrated by experimental results on the Iris dataset,Wine dataset,Multiple Features dataset,Wireless Indoor Localization dataset and Avila dataset. 展开更多
关键词 machine LEARNING MULTI-CLASS classification K-MEANS MULTI-TASK relationship LEARNING (MTRL) OVER-FITTING
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A new method of lung sounds filtering using modulated least mean square—Adaptive noise cancellation
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作者 Noman Qaid Al-Naggar 《Journal of Biomedical Science and Engineering》 2013年第9期869-876,共8页
Advanced processing of lung sound (LS) recording is a significant means to separate heart sounds (HS) and combined low frequency noise from instruments (NI), with saving its characteristics. This paper proposes a new ... Advanced processing of lung sound (LS) recording is a significant means to separate heart sounds (HS) and combined low frequency noise from instruments (NI), with saving its characteristics. This paper proposes a new method of LS filtering which separates HS and NI simultaneously. It focuses on the application of least mean squares (LMS) algorithm with adaptive noise cancelling (ANC) technique. The second step of the new method is to modulate the reference input r1(n) of LMS-ANC to acquiesce combining HS and NI signals. The obtained signal is removed from primary signal (original lung sound recording-LS). The original signal is recorded from subjects and derived HS from it and it is modified by a band pass filter. NI is simulated by generating approximately periodic white gaussian noise (WGN) signal. The LMS-ANC designed algorithm is controlled in order to determine the optimum values of the order L and the coefficient convergence μ. The output results are measured using power special density (PSD), which has shown the effectiveness of our suggested method. The result also has shown visual difference PSD (to) normal and abnormal LS recording. The results show that the method is a good technique for heart sound and noise reduction from lung sounds recordings simultaneously with saving LS characteristics. 展开更多
关键词 LUNG sound FILTERING of LUNG sound Least Mean SQUARES Algorithm Adaptive Noise Cancelling
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Mean Difference and Mean Deviation of Tukey Lambda Distribution
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作者 Giovanni Girone Antonella Massari +1 位作者 Fabio Manca Angela Maria D’Uggento 《Applied Mathematics》 2020年第8期771-778,共8页
The purpose of this paper is to broaden the knowledge of mean difference and,<span><span><span style="font-family:;" "=""> </span></span></span><span sty... The purpose of this paper is to broaden the knowledge of mean difference and,<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">in particular, of an important distribution model known as Tukey lambda, which is generally used to choose a model to fit data.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">We have obtained compact formulas, which are not yet reported in literature, of mean deviation and mean difference related to the said distribution model.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">These results made it possible to analyze the relationships among variability indexes, namely standard deviation, mean deviation and mean difference, regarding Tukey lambda model.</span></span></span> 展开更多
关键词 Mean Difference Mean Deviation Tukey Lambda Distribution Variability Indexes’ relationships
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Feasibility of the 2-point method to determine the load-velocity relationship variables during the countermovement jump exercise
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作者 Alejandro Pérez-Castilla Rodrigo Ramirez-Campillo +1 位作者 John F.T.Fernandes Amador García-Ramos 《Journal of Sport and Health Science》 SCIE CAS CSCD 2023年第4期544-552,F0003,共10页
Purpose:This study aimed to examine the reliability and validity of load-velocity(L-V)relationship variables obtained through the 2-point method using different load combinations and velocity variables.Methods:Twenty ... Purpose:This study aimed to examine the reliability and validity of load-velocity(L-V)relationship variables obtained through the 2-point method using different load combinations and velocity variables.Methods:Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads(20 kg,40 kg,60 kg,and80 kg)and a heavy squat against a load linked to a mean velocity(MV)of 0.55 m/s(load_(0.55)).The L-V relationship variables(load-axis intercept(L_(0)),velocity-axis intercept(v_(0)),and area under the L-V relationship line(A_(line)))were obtained using 3 velocity variables(MV,mean propulsive velocity(MPV),and peak velocity)by the multiple-point method including(20-40-60-80-load_(0.55))and excluding(20-40-60-80)the heavy squat,as well as from their respective 2-point methods(20-load_(0.55)and 20-80).Results:The L-V relationship variables were obtained with an acceptable reliability(coefncient of variation(CV)≤7.30%;intra-class correlation coefficient>0.63).The reliability of L_(0)and v_(0)was comparable for both methods(CV_(ratio)(calculated as higher value/lower value):1.11-1.12),but the multiple-point method provided Al_(ine)with a greater reliability(CV_(ratio)=1.26).The use of a heavy squat provided the L-V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load(CV_(ratio):1.06-1.19).The peak velocity provided the load-velocity relationship variables with the greatest reliability(CV_(ratio):1.15-1.86)followed by the MV(CV_(ratio):1.07-1.18),and finally the MPV.The 2-point methods only revealed an acceptable validity for the MV and MPV(effect size≤0.19;Pearson s product-moment correlation coefficient≥0.96;Lin's concordance correlation coefficient≥0.94).Conclusion:The 2-point method obtained from a heavy squat load and MV or MPV is a quick,safe,and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L-V relationship. 展开更多
关键词 Force-velocity relationship Mean velocity Multiple-point method Peak velocity Velocity-based training
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New era of cystic fibrosis:Full mutational analysis and personalized therapy
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作者 Marco Lucarelli 《World Journal of Medical Genetics》 2017年第1期1-9,共9页
Despite its apparently simple genetics,cystic fibrosis(CF) is a rather complex genetic disease.A lot of variability in the steps of the path from the cystic fibrosis transmembrane conductance regulator(CFTR) gene to t... Despite its apparently simple genetics,cystic fibrosis(CF) is a rather complex genetic disease.A lot of variability in the steps of the path from the cystic fibrosis transmembrane conductance regulator(CFTR) gene to the clinical manifestations originates an uncertain genotype- phenotype relationship.A major determinant of this uncertainty is the incomplete knowledge of the CFTR mutated genotypes,due to the high number of CFTR mutations and to the higher number of their combinations in trans and in cis.Also the very limited knowledge of functional effects of CFTR mutated alleles severely impairs our diagnostic and prognostic ability.The final phenotypic modulation exerted by CFTR modifier genes and interactome further complicates the framework.The next generation sequencing approach is a rapid,lowcost and high-throughput tool that allows a near complete structural characterization of CFTR mutated genotypes,as well as of genotypes of several other genes cooperating to the final CF clinical manifestations.This powerful method perfectly complements the new personalized therapeutic approach for CF.Drugs active on specific CFTR mutational classes are already available for CF patients or are in phase 3 trials.A complete genetic characterization has been becoming crucial for a correct personalized therapy.However,the need of a functional classification of each CFTR mutation potently arises.Future big efforts towards an ever more detailed knowledge of both structural and functional CFTR defects,coupled to parallel personalized therapeutic interventions decisive for CF cure can be foreseen. 展开更多
关键词 GENOTYPE-PHENOTYPE relationship CFTR CYSTIC fibrosis Next generation sequencing FUNCTIONAL meaning of mutations Personalized therapy MUTATION search MUTATION FUNCTIONAL classes
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习近平新时代中国特色社会主义思想的世界观和方法论:辩证关系、核心要义与实践指向 被引量:2
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作者 周向军 庞付玲 《新疆师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2024年第1期58-66,F0002,共10页
把握好习近平新时代中国特色社会主义思想的世界观和方法论,要正确认识和处理世界观和方法论的关系、习近平新时代中国特色社会主义思想的世界观和方法论与马克思主义世界观和方法论的关系、与中华优秀传统文化的关系、与习近平新时代... 把握好习近平新时代中国特色社会主义思想的世界观和方法论,要正确认识和处理世界观和方法论的关系、习近平新时代中国特色社会主义思想的世界观和方法论与马克思主义世界观和方法论的关系、与中华优秀传统文化的关系、与习近平新时代中国特色社会主义思想的关系。要从不同维度深刻领悟其核心要义,即必须坚持人民至上、必须坚持自信自立、必须坚持守正创新、必须坚持问题导向、必须坚持系统观念、必须坚持胸怀天下。习近平新时代中国特色社会主义思想的世界观和方法论具有强烈的实践指向性,要在学好用好马克思主义哲学的基础上,在“两个结合”中不断推进马克思主义中国化时代化,为新时代新征程推进中国式现代化提供行动指南。 展开更多
关键词 习近平新时代中国特色社会主义思想 世界观和方法论 辩证关系 核心要义 实践指向
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健听成年人全方向水平声源定位能力初步研究
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作者 户红艳 李思阳 +3 位作者 王倩 叶放蕾 李楠 冀飞 《中华耳科学杂志》 CSCD 北大核心 2024年第5期709-714,共6页
目的利用360°全方向24和36声源测试设备,初步探讨健听中青年和健听老年前期-老年人水平声源定位特点。方法选取2021年4月至2021年9月中国人民解放军总医院耳鼻喉科收治的43例健听成年受试者为研究对象,其中男性22例,女性21例;根据... 目的利用360°全方向24和36声源测试设备,初步探讨健听中青年和健听老年前期-老年人水平声源定位特点。方法选取2021年4月至2021年9月中国人民解放军总医院耳鼻喉科收治的43例健听成年受试者为研究对象,其中男性22例,女性21例;根据年龄分为中青年组(21~49岁)20例和老年前期-老年组(50~72岁)23例。两组分别给予纯音听阈测试、全方向24声源(间隔15°)和36声源(间隔10°)水平声源定位(sound localization,SL)能力评估。给声强度60 dB HL,给声刺激为1 kHz啭音,通过计算均方根误差(root mean square,RMS)、平均绝对误差(mean absolutely error,MAE)等评估受试者的声源定位能力。结果24声源老年前期-老年组MAE、RMS均值高于中青年组的MAE、RMS均值,差异有统计学意义(P<0.05);36声源老年前期-老年组MAE、RMS高于中青年组的MAE、RMS,差异无统计学意义(P>0.05)。24声源和36声源前场MAE和RMS均高于后场的MAE和RMS,前后场的MAE和RMS比较,差异有统计学意义(P<0.01);左右场的MAE、RMS比较,差异无统计学意义(P>0.05)。24声源前后混淆比例为7.73%,36声源前后混淆比例为15.42%;24声源和36声源均为正前方的声源定位准确度最差;老年前期-老年组前后混淆的比例高于中青年组,差异无统计学意义(P>0.05)。结论健听老年前期-老年人全方向24声源和36声源水平定位能力,相比健听中青年组有所下降。左右场的定位准确度高,前后场的定位准确度低,正前方定位准确度最低。全方向水平声源定位能力的测试结果与扬声器数量有关,且反应趋势具有一致性。 展开更多
关键词 声源定位 360°全方向 均方根误差 平均绝对误差 前后混淆
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置于发生学与现象学论域的“情—声”关系讨论
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作者 韩锺恩 《音乐艺术(上海音乐学院学报)》 CSSCI 北大核心 2024年第4期4-18,共15页
文章以“情—声”关系为中心,进一步勾连与牵扯感性结构力问题,并置于发生学与现象学论域,分别就“原始情感的纯粹音调”“原始美学规范想像”“有声信号传递超生物经验”“心理能量的物理释放”“现象学结构转换”“音乐作品的二重存... 文章以“情—声”关系为中心,进一步勾连与牵扯感性结构力问题,并置于发生学与现象学论域,分别就“原始情感的纯粹音调”“原始美学规范想像”“有声信号传递超生物经验”“心理能量的物理释放”“现象学结构转换”“音乐作品的二重存在方式”“始端终端、他律自律、立美审美互动”“思—诗关系”“事—诗关系”“直观本质洞察”“相即”等问题进行讨论。 展开更多
关键词 “情—声”关系 感性结构力 发生学 现象学
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老年人家庭代际关系模式及其影响因素研究——基于代际双向报告的K均值聚类分析
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作者 张航空 马琦峰 杨磊 《人口与经济》 CSSCI 北大核心 2024年第1期103-117,共15页
在传统的代际关系模式研究中,数据往往来自家庭中父母或子女一方的报告,然而仅凭借“一面之词”对代际关系进行测量真的准确吗?这一问题的背后透视出当前国内相关研究中双向报告视角的缺失。利用2020年中国家庭追踪调查(CFPS)数据,运用... 在传统的代际关系模式研究中,数据往往来自家庭中父母或子女一方的报告,然而仅凭借“一面之词”对代际关系进行测量真的准确吗?这一问题的背后透视出当前国内相关研究中双向报告视角的缺失。利用2020年中国家庭追踪调查(CFPS)数据,运用K均值聚类分析及多层Logistic回归方法,探究当前中国老年人家庭中代际关系的双向报告状况、代际关系模式及其影响因素。研究结果表明:首先,老年父母的代际关系报告平均得分要略低于成年子女的报告平均得分,但两者间并不存在显著差异,代际利益假说未获支持。其次,基于双向报告的聚类结果,可将老年人家庭代际关系具体划分为结构维度上的“亲子一致型”、“亲近子疏型”、“亲疏子近型”模式与水平维度上的“亲子和睦型”、“亲子有隙型”、“亲子疏离型”模式。最后,从代际关系模式的影响因素来看,代际结构、老年父母特征及成年子女特征均会在结构维度与水平维度上产生显著影响,而家庭特征仅在水平维度上产生显著影响。简言之,两代人的年龄差距越大、父母年龄越小、子女年龄越大,越可能形成评价一致的代际关系;两代人的年龄差距越大、两代人的性别一致、父母年龄越小、父母获得子女支持以及在城镇家庭中,越可能形成和睦的代际关系。 展开更多
关键词 老年人家庭 代际关系模式 双向报告 K均值聚类分析
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肺音信号去噪技术的比较与分析
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作者 郭涛 陈梦凡 +1 位作者 李进 石帅 《计算机与数字工程》 2024年第4期1098-1102,共5页
肺音听诊是医生诊断各种呼吸系统疾病的一种简单、无创的方法,可为检测和鉴别呼吸病理提供及时而有用的信息。然而,肺音中的噪声污染是采集肺音时不可避免的问题,在医生诊断患者时,噪声的存在会对肺音分析产生严重阻碍,因此有效去除多... 肺音听诊是医生诊断各种呼吸系统疾病的一种简单、无创的方法,可为检测和鉴别呼吸病理提供及时而有用的信息。然而,肺音中的噪声污染是采集肺音时不可避免的问题,在医生诊断患者时,噪声的存在会对肺音分析产生严重阻碍,因此有效去除多余噪声更有助于准确、客观地评价肺音信息。论文对不同去噪技术进行了讨论,包括小波去噪、最小均方自适应滤波、谱减法,评估了三种去噪性能指标,得出了相关比较性结论。 展开更多
关键词 肺音 小波分析 最小均方自适应滤波 谱减法
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欺骗型强奸案定性争议问题研究——基于2009—2023年相关判例的解读
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作者 邱帅萍 杨伟旭 《湖南警察学院学报》 2024年第3期73-82,共10页
对我国2009年至2023年网上已公布的欺骗型强奸案进行实证分析,发现对以封建迷信为手段、以冒充特定关系为手段、以假冒治病为手段、以利益诱骗为手段的欺骗型性交的定性仍存在较大争议。基于刑法教义学的立场,应以实质判断为基础,扩大... 对我国2009年至2023年网上已公布的欺骗型强奸案进行实证分析,发现对以封建迷信为手段、以冒充特定关系为手段、以假冒治病为手段、以利益诱骗为手段的欺骗型性交的定性仍存在较大争议。基于刑法教义学的立场,应以实质判断为基础,扩大以冒充特定关系为手段中“特定关系”的认定范围,宜以“最广义上的推定同意说”作为判断标准、拓宽以假冒治病为手段中推定同意的场景、摒弃意志自由判断的“唯主体论”标准,进而精准识别不同类型的欺骗型性交中的强迫性与欺骗性,合理界定欺骗型性交罪与非罪的界限。 展开更多
关键词 强奸罪 欺骗型强奸 手段强制性 同意无效性 法益关系错误
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因声求义七则
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作者 杨琳 《汉字汉语研究》 2024年第1期96-105,127,共11页
本文用因声求义法考释了“门扶、點叶、拭然、妆哈、油回磨转、胡基、央及”七则疑难词语,揭示本字,理清含义,阐明词源。
关键词 因声求义 點叶 妆哈 胡基 央及
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基于改进K-means聚类和皮尔逊相关系数户变关系异常诊断 被引量:4
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作者 周纲 黄瑞 +3 位作者 刘度度 张芝敏 胡军华 高云鹏 《电测与仪表》 北大核心 2024年第3期76-82,152,共8页
用电信息采集系统易出现台区户变关系错误问题,传统诊断技术主要针对少用户台区出现异常用户情况,但对于多达数百用户台区,存在多相邻台区异常用户特征提取难题。文中首先通过主成分分析对GIS系统获取台区总表和用户电表电压数据实现降... 用电信息采集系统易出现台区户变关系错误问题,传统诊断技术主要针对少用户台区出现异常用户情况,但对于多达数百用户台区,存在多相邻台区异常用户特征提取难题。文中首先通过主成分分析对GIS系统获取台区总表和用户电表电压数据实现降维,建立改进K-means聚类提取电压数据特征,提出改进皮尔逊相关系数算法分析待检测用户,据此建立基于改进K-means聚类和改进皮尔逊相关系数的户变关系异常诊断方法,实现多异常用户所属正确台区诊断。实际算例分析结果表明,文中提出算法在识别同一台区一个及多个异常用户、不同台区多个异常用户情况下均能有效实现异常用户的准确检测与分析,相比传统检测方法,实现简单且准确性更高。 展开更多
关键词 户变关系 GIS系统 主成分分析 改进K-means聚类
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面向城市交通噪声控制的树种筛选与种植策略
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作者 李朦朦 Timothy Van Renterghem +2 位作者 孟琪 Dick Botteldooren 康健 《应用声学》 CSCD 北大核心 2024年第4期843-853,共11页
植物降噪是一种减碳且低成本的降噪方式,可有效改善城市声环境。然而现存植物降噪影响因素与预测模型主要集中在植物群落层面,忽略了树种间差异在不同频率噪声控制过程中的重要作用,难以满足城市交通噪声有效防控的需求。基于此,该研究... 植物降噪是一种减碳且低成本的降噪方式,可有效改善城市声环境。然而现存植物降噪影响因素与预测模型主要集中在植物群落层面,忽略了树种间差异在不同频率噪声控制过程中的重要作用,难以满足城市交通噪声有效防控的需求。基于此,该研究以植物树干为切入点,提出一种量化树干与树皮粗糙度的方法,针对交通噪声频谱特征系统测量13种树种的吸收作用,并模拟降噪效果。研究首先测得树干吸声系数的频谱特征,确定了树干主要吸声频率范围与交通噪声频率分布具备较好的一致性;其次,从树种视角分析视觉因素与测试获取因素两个层面对树干吸声效果有影响的主要因素;最后,通过模拟对比分析15 m宽植物带种植不同树种的降噪效果,发现相差∼0.9 dBA,证明了种植吸声系数高的树种对交通噪声控制的有效性。以期从树形、树干吸声效果、树种生长速度以及种植方式等方面,提出应对城市交通噪声污染的树种筛选依据与设计策略。 展开更多
关键词 噪声控制 交通噪声 吸声系数 自然降噪途径
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非人与人关系能动性实践及其在空间意义生产中的价值 被引量:2
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作者 郭文 《地理科学》 CSSCI CSCD 北大核心 2024年第2期288-296,共9页
在传统观念中,非人类能动性及其在空间意义生产中的价值很长时间没有得到承认,随着“后人类主体”思想和地理学“重返唯物主义”思潮的兴起,人们对非人与人关系能动性有了新的认识,认为将非人与人定义为“行动元”比“行动者”更加科学... 在传统观念中,非人类能动性及其在空间意义生产中的价值很长时间没有得到承认,随着“后人类主体”思想和地理学“重返唯物主义”思潮的兴起,人们对非人与人关系能动性有了新的认识,认为将非人与人定义为“行动元”比“行动者”更加科学。研究提出“非人与人关系能动性–空间叠写–意义生产”命题和假设,并结合大学校园微观地理空间,通过3组时间镜头进行了观察分析,认为非人具有重要的能动性,非人与人关系能动性实践在空间叠写过程中,通过双方情感的相互性和流动性,使人们产生了地理想象和地方意象,建构了空间关系和地方认同,塑造了恋地情结和社会责任感。非人与人关系能动性价值认知转换对人与自然生命共同体建设具有推动作用,其实践知识也比传统文化隐喻知识更具有科学性,通过他者导向的地方性形成机制对既往研究具有延伸意义。未来应重视非人与人关系能动性在教育中的作用和力量。研究对坚守自然–人类能动协同主义、教育能动性实践主体的边界拓展以及非人与人关系能动性在国家社会转型时期的人地和谐实践具有借鉴意义与启发作用。 展开更多
关键词 非人类与人类主体 关系能动性 空间叠写 空间意义生产 能动性价值
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基于平均声速测量的声速剖面实时重构方法 被引量:1
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作者 王旭 刘宗伟 +3 位作者 甘忠良 姜莹 杨春梅 吕连港 《海洋科学进展》 CAS CSCD 北大核心 2024年第3期602-610,共9页
针对传统的声速剖面重构方法往往不具备实时性的问题,本文提出了一种基于平均声速测量的声速剖面实时重构方法。首先,基于历史数据进行特征分解并选择经验正交函数(Empirical Orthogonal Function, EOF)的阶次;其次,利用实测的水下某深... 针对传统的声速剖面重构方法往往不具备实时性的问题,本文提出了一种基于平均声速测量的声速剖面实时重构方法。首先,基于历史数据进行特征分解并选择经验正交函数(Empirical Orthogonal Function, EOF)的阶次;其次,利用实测的水下某深度的声速和该深度至海面的平均声速,通过求二元一次方程组的最小范数解得到EOF重构系数;最后,结合历史声速剖面重构全海深声速剖面。使用西太平洋海域的再分析数据对该方法进行了仿真验证,结果表明:采用该方法重构的声速剖面与真实声速剖面拟合效果较好,平均均方根误差约为1.31 m·s-1。本文所提方法可为水下航行器实时重构声速剖面提供技术支撑。 展开更多
关键词 实时重构 经验正交函数 平均声速 最小范数解
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