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Positioning Precision Analysis of GNSS Multi-frequency Carrier Phase Combinations 被引量:2
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作者 WU Yue PAN Yong +1 位作者 FAN Yimin WANG Xiaojun 《Geo-Spatial Information Science》 2007年第4期245-249,共5页
GPS positioning precision is affected by various error sources, and traditional combinations of GPS carrier phase observations have their own limitations such as the wide-lane, the narrow-lane and the ionospheric-free... GPS positioning precision is affected by various error sources, and traditional combinations of GPS carrier phase observations have their own limitations such as the wide-lane, the narrow-lane and the ionospheric-free combinations. To obtain the optimal positioning precision, a new linear combination method is addressed through the variance-covariance (VCV) of the GPS multi-frequency carrier phase combination equations, and the impact of the positioning precision is analyzed with the changing of the observation errors deduced by the law of error propagation. For the high precision positioning with only one carrier phase combination, the optimal combination method is deduced and further validated by an example of a baseline resolution with 60 km length. The result indicates that this method is the simplest, and the positioning precision is the best. Therefore, it is useful for long baseline quick positioning for different precision requirements in various distances. 展开更多
关键词 GPS multi-frequency combination propagation of errors positioning precision
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Multi-mode Multi-frequency GNSS-IR Combination System for Sea Level Retrieval
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作者 Wenyue CHE Xiaolei WANG +1 位作者 Xiufeng HE Jin LIU 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第2期32-39,共8页
With the development of Global Navigation Satellite Systems(GNSS),geodetic GNSS receivers have been utilized to monitor sea levels using GNSS-Interferometry Reflectometry(GNSS-IR)technology.The multi-mode,multi-freque... With the development of Global Navigation Satellite Systems(GNSS),geodetic GNSS receivers have been utilized to monitor sea levels using GNSS-Interferometry Reflectometry(GNSS-IR)technology.The multi-mode,multi-frequency signals of GPS,GLONASS,Galileo,and Beidou can be used for GNSS-IR sea level retrieval,but combining these retrievals remains problematic.To address this issue,a GNSS-IR sea level retrieval combination system has been developed,which begins by analyzing error sources in GNSS-IR sea level retrieval and establishing and solving the GNSS-IR retrieval equation.This paper focuses on two key points:time window selection and equation stability.The stability of the retrieval combination equations is determined by the condition number of the coefficient matrix within the time window.The impact of ill-conditioned coefficient matrices on the retrieval results is demonstrated using an extreme case of SNR data with only ascending or descending trajectories.After determining the time window and removing ill-conditioned equations,the multi-mode,multi-frequency GNSS-IR retrieval is performed.Results from three International GNSS Service(IGS)stations show that the combination method produces high-precision,high-resolution,and high-reliability sea level retrieval combination sequences. 展开更多
关键词 GNSS-IR sea level retrieval multi-mode multi-frequency combination equation stability
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An adaptive over/under data combination method 被引量:4
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作者 赫建伟 陆文凯 李钟晓 《Applied Geophysics》 SCIE CSCD 2013年第4期469-476,512,共9页
The traditional "dephase and sum" algorithms for over/under data combination estimate the ghost operator by assuming a calm sea surface. However, the real sea surface is typically rough, which invalidates the calm s... The traditional "dephase and sum" algorithms for over/under data combination estimate the ghost operator by assuming a calm sea surface. However, the real sea surface is typically rough, which invalidates the calm sea surface assumption. Hence, the traditional "dephase and sum" algorithms might produce poor-quality results in rough sea conditions. We propose an adaptive over/under data combination method, which adaptively estimates the amplitude spectrum of the ghost operator from the over/under data, and then over/under data combinations are implemented using the estimated ghost operators. A synthetic single shot gather is used to verify the performance of the proposed method in rough sea surface conditions and a real triple over/under dataset demonstrates the method performance. 展开更多
关键词 Over/under data combination dephase and sum deghost amplitude spectrum
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Research on Data Combination for Phased-Array Ground Penetrating Radar 被引量:1
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作者 Zou Lian Chen Shu-zhen +1 位作者 Shi Jing Xiao Bo-xun 《Wuhan University Journal of Natural Sciences》 CAS 2003年第04A期1111-1115,共5页
To resolve the data combination of Phased-array Ground Penetrating Radar (PAGPR), we first build a model of PAGPR and a layered model, and then a new data combination algorithm is presented based on it. This method ca... To resolve the data combination of Phased-array Ground Penetrating Radar (PAGPR), we first build a model of PAGPR and a layered model, and then a new data combination algorithm is presented based on it. This method calculates time delay of multi-receivers, basing on the signal of the nearest receiver, then shifts other signals and adds them up, and gets one signal at last. It has been proved that this method can restrain noise, multiple waves, clutter waves and improve the precision of time location. In the end, an example is given to prove the method's efficiency. 展开更多
关键词 data combination phased-array radar ground penetrating radar signal processing
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Determination of Light Rare Earths by a Spectrophoto-metry Based on the Linear Combination of Multiwavelength Data
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作者 刘思东 崔秀君 +1 位作者 郭伊荇 李永涛 《Journal of Rare Earths》 SCIE EI CAS CSCD 1993年第3期211-215,共5页
The present paper proposes a new method of spectrophotometry based on linear combination of multiwavelength data by means of selecting a set of properly weighted coefficients and combination methods. It is clear that ... The present paper proposes a new method of spectrophotometry based on linear combination of multiwavelength data by means of selecting a set of properly weighted coefficients and combination methods. It is clear that the weighted combination absorbance attained is only in direct proportion to the concentration of the analysed component and independent of coexisting interferents.The accuracy of the analytical results is improved greatly for the analysis of light rare earths with the coexistence of heavy rare earths.The analyti- cal error from the reagent blank and co-coloration of light and heavy rare earths have also been overcome. The greatly improved linearity and additivity of absorbance are obtained. 展开更多
关键词 Linear combination of multiwavelength data Computational spectrophotometry CPAⅢ Determination of light rare earths
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Combination of structure tensor and tilt angle in the edge detection of potential field data
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作者 LIN Song LI Lili SHI Jianan 《Global Geology》 2018年第4期252-259,共8页
Edge detection is a commonly requested task in the interpretation of potential field data. Different methods have different results for varied depths and shapes of geological bodies. In this paper,we propose using the... Edge detection is a commonly requested task in the interpretation of potential field data. Different methods have different results for varied depths and shapes of geological bodies. In this paper,we propose using the combination of structure tensor and tilt angle to detect the edges of the sources,which can display the edges of shallow and deep bodies simultaneously. Through tests on synthetic potential field data,it is obvious that the proposed edge detection methods can display the sources edges more clearly and precisely,compared with other commonly used methods. The application on real potential field data shows similar result,obtaining the edges of layers and faults clearly. In addition,another advantage of the new method is its insensitivity to noise. 展开更多
关键词 combination structure TENSOR TILT ANGLE EDGE DETECTION potential field data
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Research on Construction of combined model weighting function and its application on aeromagnetic 3D inversion modeling
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作者 Gao Xiu-he Xiong Sheng-qing +2 位作者 Sun Si-yuan Zeng Zhao-fa Yu Chang-chun 《Applied Geophysics》 2025年第2期342-353,556,共13页
In the 3D inversion modeling of gravity and magnetic potential field data,the model weighting function is often applied to overcome the skin eff ect of inversion results.However,divergence occurs at the the deep area,... In the 3D inversion modeling of gravity and magnetic potential field data,the model weighting function is often applied to overcome the skin eff ect of inversion results.However,divergence occurs at the the deep area,and artificial weak negative anomalies form around the positive anomalies in the horizontal direction,resulting in a reduction in the overall resolution.To fully utilize the model weighting function,this study constructs a combined model weighting function.First,a new depth weighting function is constructed by adding a regulator into the conventional depth weighting function to overcome the skin eff ect and inhibit the divergence at the deep area of the inversion results.A horizontal weighting function is then constructed by extracting information from the observation data;this function can suppress the formation of artificial weak anomalies and improve the horizontal resolution of the inversion results.Finally,these two functions are coupled to obtain the combined model weighting function,which can replace the conventional depth weighting function in 3D inversion.It improves the vertical and horizontal resolution of the inversion results without increasing the algorithm complexity and calculation amount,is easy to operate,and adapts to any 3D inversion method.Two model experiments are designed to verify the effectiveness,practicability,and anti-noise of the combined model weighting function.Then the function is applied to the 3D inversion of the measured aeromagnetic data in the Jinchuan area in China.The obtained inversion results are in good agreement with the known geological data. 展开更多
关键词 horizontal weighting depth weighting combined weighting aeromagnetic data 3D inversion Jinchuan Orefield
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Target recognition based on modified combination rule 被引量:16
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作者 Chen Tianlu Que Peiwen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第2期279-283,共5页
Evidence theory is widely used in the field of target recognition. The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rul... Evidence theory is widely used in the field of target recognition. The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rule are analyzed and compared. A new combination approach is proposed. Calculate the reliabilities of evidence sources using existing evidences. Construct reliabilities judge matrixes and get the weights of each evidence source. Weight average all inputted evidences. Combine processed evidences with D-S combination rule repeatedly to identify a target. The application in multi-sensor target reeognition as well as the comparison with typical alternatives all validated that this approach can dispose highly conflict evidences efficiently and get reasonable reeognition results rapidly. 展开更多
关键词 evidence theory combination rule conflict evidences target recognition data fusion.
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Analysis on the rules of acupoint combination in treatment of pseudobulbar palsy based on co-occurrence relationship 被引量:1
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作者 Xiao-yu SUN Dian-hui YANG Feng DUAN 《World Journal of Acupuncture-Moxibustion》 CSCD 2022年第3期237-244,共8页
Objective:To explore the rules of acupoint combination in acupuncture treatment of post-stroke pseudobulbar palsy(PBP),based on acupuncture prescriptions retrieved from literature and using complex network analysis.Me... Objective:To explore the rules of acupoint combination in acupuncture treatment of post-stroke pseudobulbar palsy(PBP),based on acupuncture prescriptions retrieved from literature and using complex network analysis.Methods:The articles were searched from China National Knowledge Infrastructure(CNKI),Wanfang and VIP databases as the source of data.The eligible articles were selected in accordance with inclusion and exclusion criteria.The relevant data were extracted to set up the acupoint prescription database in acupuncture treatment of PBP.By using co-occurrence relationship in acupoint prescriptions,the core acupoints and the combination rules were analyzed in acupuncture treatment of PBP.Results:A total of 194 articles were eligible finally,with 202 acupoint prescriptions extracted.19 core acupoints were collected in total,i.e.Liánquán(廉泉CV23),Fēngchí(风池GB20),Bǎihuì(百会GV20),Jīnjīn(金津EX-HN12),Yùyè(玉液EX-HN13),Fēngfǔ(风府GV16),Yǎmén(哑门GV15),Shuǐgōu(水沟GV26),Nèiguān(内关PC6),Fēnglóng(丰隆ST40),Wángǔ(完骨GB12),Sānyīnjiāo(三阴交SP16),Yìfēng(翳风TE17),Tōnglǐ(通里HT5),Tàichōng(太冲LR3),Hégǔ(合谷LI4),Hǎiquán(海泉EX-HN11),Jùquán(聚泉EX-HN10)and Yìntáng(印堂EX-HN3).The core acupoint groups were CV23-GB20,EX-HN12-EX-HN13 and GV26-PC6-SP6.Acupoints were mostly selected from governor vessel.The methods of acupoint combination included the combination of distal and nearby points,and the combination of the acupoints located in the front and on the back.Conclusions:In treatment of PBP with acupuncture,biaoben(manifestation and root cause)theory is emphasized,the methods for dispelling wind,resolving phlegm,regaining consciousness,and opening orifices are recommended.Moreover,the attentions are paid on spirit regulation,holistic adjustment,and syndrome differentiation in treatment. 展开更多
关键词 ACUPUNCTURE Pseudobulbar palsy(PBP) Acupoint combination Co-word analysis data mining Gephi
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Comparative study of ancient and modern literature for Láogōng(劳宫PC8)in the indications and combination rules 被引量:1
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作者 Jie ZHANG Yong-zheng ZHU +2 位作者 Hong-Ling JIA Zhen-Ling ZHANG Yong-Chen ZHANG 《World Journal of Acupuncture-Moxibustion》 CSCD 2022年第2期168-177,共10页
Objective:To explore the clinical application rules of Láogōng(劳宫PC8)by analyzing the comparison and contrast of the practice with this acupoint in ancient times and in present.Methods:Relevant literature befo... Objective:To explore the clinical application rules of Láogōng(劳宫PC8)by analyzing the comparison and contrast of the practice with this acupoint in ancient times and in present.Methods:Relevant literature before October 1,1949 was selected from Chinese Medical Code(Fifth Edition)and Compilation of Moden Chinese Medicine Journals and literature published after October 1,1949 was screened from China National knowledge Infrastructure(CNIK),Wanfang Data Knowledge Service Platform(Wanfang),VIP Chinese Journal Service Platform(VIP),Chinese BioMedine Database(CBM),Pubmed Database,and Web of Science.After screening,SQL Server database was established.The complex network analysis was conducted by using Gephi and the cluster analysis was performed by SPSS Statistics.Results:Before October 1,1949,Lráogōng(劳宫PC8),on a single use or with a match of Dàlíng(大陵PC7),Guānyuán(关元CV4),and Zúsānlǐ(足三里ST36),was mainly used for treating ozostomia and edema due to pregnancy.However,Láogōng(劳宫PC8),on a single use or with a match of Yǒngquán(涌泉KI1),Hégǔ(合谷L14)and Nèiguān(内关PC6)was commonly for the treatment of toothache and the sequelae after wind stroke after October 1 st,1949.Conclusion:Láogōng(劳宫PC8)is mainly used to treat local disorders or diseases pertaining to the pericardium meridian.The single-point therapy was commonly applied before October 1 st,1949,while a combination of other points is more common afterwards and the scope of indication expands,with its application for psychiatry disorders,pain diseases and emergent diseases.Acupoints on the same meridian of Láogōng(劳宫PC8),ying-spring points,the back-shu points and combination between and the upper and the lower are dominated in the selection of supplementary points.The supplementary acupoints with the highest frequency of use were specific acupoints,including five-shu points,yuan-source points,front-mu points,etc。 展开更多
关键词 Láogōng(劳宫PC8) INDICATIONS Acupoint combination data mining
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Data-driven model-free adaptive attitude control of partially constrained combined spacecraft with external disturbances and input saturation 被引量:6
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作者 Han GAO Guangfu MA +1 位作者 Yueyong LYU Yanning GUO 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第5期1281-1293,共13页
This study presents an improved data-driven Model-Free Adaptive Control(MFAC)strategy for attitude stabilization of a partially constrained combined spacecraft with external disturbances and input saturation. First, a... This study presents an improved data-driven Model-Free Adaptive Control(MFAC)strategy for attitude stabilization of a partially constrained combined spacecraft with external disturbances and input saturation. First, a novel dynamic linearization data model for the partially constrained combined spacecraft with external disturbances is established. The generalized disturbances composed of external disturbances and dynamic linearization errors are then reconstructed by a Discrete Extended State Observer(DESO). With the dynamic linearization data model and reconstructed information, a DESO-MFAC strategy for the combined spacecraft is proposed based only on input and output data. Next, the input saturation is overcome by introducing an antiwindup compensator. Finally, numerical simulations are carried out to demonstrate the effectiveness and feasibility of the proposed controller when the dynamic properties of the partially constrained combined spacecraft are completely unknown. 展开更多
关键词 Attitude CONTROL combinED SPACECRAFT data-DRIVEN CONTROL Discrete Extended State Observer(DESO) Input SATURATION
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Determination of combined effect of ampli- fication and attenuation of soft rock site us- ing digital seismic data
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作者 姜慧 高孟潭 +1 位作者 俞言祥 赵翠萍 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第z1期157-162,共6页
In the paper, for the application of stochastic simulation of ground motion, we put forward a method to determine ″the combined effect of amplification and attenuation″ (combined effect for short) of soft rock site... In the paper, for the application of stochastic simulation of ground motion, we put forward a method to determine ″the combined effect of amplification and attenuation″ (combined effect for short) of soft rock site by using digital seismic data of moderate and small earthquakes. Our approach aims at solving the problem of the combined effect of soft rock site, which is difficult to determine in most regions of China because fewer measures were done for S-wave velocity structure. The combined effect of soft rock site can be determined by using the approach recom- mended by us. An example is given to discuss the practical application of the method. 展开更多
关键词 digital seismic data soft rock combined effect
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Phylogeny of subclass Scuticociliatia(Protozoa,Ciliophora) using combined data inferred from genetic,morphological,and morphogenetic evidence
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作者 伊珍珍 王艳刚 +2 位作者 林晓凤 Khaled A.S.AL-RASHEID 宋微波 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第4期778-784,共7页
Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test t... Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group. 展开更多
关键词 CILIOPHORA Scuticociliatia phylogenetic analyses combined data
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COMBINATION OF ECMWF REANALYZED DAILY RAINFALL AND PENTAD CMAP IN CHINA
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作者 崔茂常 朱海 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2001年第3期200-207,共8页
In this study, 16 combinations of the ECMWF (European Centre for Medium Range Weather Forecast) reanalyzed daily rainfall and the pentad CMAP in China for the period 1980-1993(1 May-31 Dec.) were calculated. Correlati... In this study, 16 combinations of the ECMWF (European Centre for Medium Range Weather Forecast) reanalyzed daily rainfall and the pentad CMAP in China for the period 1980-1993(1 May-31 Dec.) were calculated. Correlation analysis was used to roughly evaluate daily rainfall for the whole of China and a combination of RPC (rotated principal component) and wavelet analyses was applied to data on observed and combined daily rainfall to obtain a detailed evaluation of the quality of these combined datasets in 6 selected major rainfall regions of eastern China. The results showed that except for intraweekly fluctuation, the best combination was roughly similar to or accorded well with observation in the aspects of space variation patterns and long period rainfall fluctuations related to monsoon onset and serious meteorologic disasters, indicating that this combination yielded better values of long term daily mean and standard deviation through the pentad CMAP (CPC Merged Analysis of Precipitation), and can also represent rainfall fluctuations through the reanalyzed daily rainfall. 展开更多
关键词 data combination daily rainfall in China ECMWF reanalysis pentad CMAP
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Evaluating the Potentials of PLSR and SVR Models for Soil Properties Prediction Using Field Imaging,Laboratory VNIR Spectroscopy and Their Combination
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作者 Emna Karray Hela Elmannai +4 位作者 Elyes Toumi Mohamed Hedi Gharbia Souham Meshoul Hamouda Aichi Zouhaier Ben Rabah 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第8期1399-1425,共27页
Pedo-spectroscopy has the potential to provide valuable information about soil physical,chemical,and biological properties.Nowadays,wemay predict soil properties usingVNIRfield imaging spectra(IS)such as Prisma satell... Pedo-spectroscopy has the potential to provide valuable information about soil physical,chemical,and biological properties.Nowadays,wemay predict soil properties usingVNIRfield imaging spectra(IS)such as Prisma satellite data or laboratory spectra(LS).The primary goal of this study is to investigate machine learning models namely Partial Least Squares Regression(PLSR)and Support Vector Regression(SVR)for the prediction of several soil properties,including clay,sand,silt,organic matter,nitrate NO3-,and calcium carbonate CaCO_(3),using five VNIR spectra dataset combinations(%IS,%LS)as follows:C1(0%IS,100%LS),C2(20%IS,80%LS),C3(50%IS,50%LS),C4(80%IS,20%LS)and C5(100%IS,0%LS).Soil samples were collected at bare soils and at the upper(0–30 cm)layer.The data set has been split into a training dataset 80%of the collected data(n=248)and a validation dataset 20%of the collected data(n=61).The proposed PLSR and SVR models were trained then tested for each dataset combination.According to our results,SVR outperforms PLSR for both:C1(0%IS,100%LS)and C5(100%IS,0%LS).For Soil Organic Matter(SOM)prediction,it achieves(R^(2)=0.79%,RMSE=1.42%)and(R^(2)=0.76%,RMSE=1.3%),respectively.The data fusion has improved the soil property prediction.The highest improvement was obtained for the SOM property(R^(2)=0.80%,RMSE=1.39)when using the SVR model and applying the second Combination C2(20% of IS and 80%LS). 展开更多
关键词 Soil VNIR field imaging spectroscopy PLSR SVR VNIR data combination
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关于模块化数据中心与边缘计算结合的分析研究 被引量:1
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作者 张福友 徐雷 +1 位作者 施诗 刘斌 《智能建筑电气技术》 2025年第1期53-56,共4页
模块化数据中心与边缘计算的结合,不仅能够满足新兴技术对基础设施的需求,还能够提供更高效、低成本的解决方案,以支持各种高密度、大带宽和低时延的业务场景,可优化数据流,提高系统可靠性,对现代数据处理需求提供了创新解决方案。本文... 模块化数据中心与边缘计算的结合,不仅能够满足新兴技术对基础设施的需求,还能够提供更高效、低成本的解决方案,以支持各种高密度、大带宽和低时延的业务场景,可优化数据流,提高系统可靠性,对现代数据处理需求提供了创新解决方案。本文深入探讨了模块化数据中心与边缘计算的结合,分析其架构设计、技术集成以及面临的挑战等,并通过实际案例分析,展示模块化数据中心与边缘计算结合在不同场景下的应用价值,期望为数据中心设计与优化提供新的视角,并为未来的技术发展指明方向。 展开更多
关键词 模块化数据中心 边缘计算 结合分析
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地下水背景值评估研究进展
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作者 闫纲丽 冯屾 +1 位作者 刘睿男 黄冠星 《吉林大学学报(地球科学版)》 北大核心 2025年第5期1655-1670,共16页
选取适宜的地下水背景值评估方法是客观认知地下水背景值的关键。本文在回顾地下水背景值研究发展历程的基础上,概述了现有评估方法及其优缺点,并指出其未来发展趋势。地下水背景值评估方法大致可分为基于未被污染地下水样本的方法、预... 选取适宜的地下水背景值评估方法是客观认知地下水背景值的关键。本文在回顾地下水背景值研究发展历程的基础上,概述了现有评估方法及其优缺点,并指出其未来发展趋势。地下水背景值评估方法大致可分为基于未被污染地下水样本的方法、预筛选法、数理统计法、基于图谱的探索性数据分析方法及多方法组合等五类。其中:基于未被污染地下水样本的方法因其自身局限性较强已很少采用;预筛选法和数理统计法是当前常用单一类方法,前者主观性较强而后者客观性更优;基于图谱的探索性数据分析方法少见单独使用,多与其他方法组合联用;多方法组合通过互补单一方法的局限性已经成为地下水背景值评估研究的重要发展方向。多方法组合中:预筛选-数理统计组合方法最常见,应用较广;新兴的基于图谱的探索性数据分析方法与预筛选法、数理统计法或预筛选-数理统计法三种方法中的其中一种分别组合的方法更为优越,但该类组合方法的使用往往需要以研究区水文地球化学的深入认知为基础,便捷性和普适性不如预筛选-数理统计组合方法。多方法组合已成为地下水背景值评估研究的主要发展趋势。 展开更多
关键词 地下水 背景值 预筛选法 数理统计法 基于图谱的探索性数据分析 组合方法
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基于组合模型的风洞试验六元力预测
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作者 宋佳音 张林 周宏威 《自动化技术与应用》 2025年第9期6-11,共6页
风洞试验对于试验设备和场地具有较高要求,且耗时长,成本高,数据获取困难。为此提出基于组合模型对风洞试验六元力进行预测。首先利用SMOTE过采样方法对风洞试验小样本数据进行数据扩充,然后采用极限梯度提升算法(extreme gradient boos... 风洞试验对于试验设备和场地具有较高要求,且耗时长,成本高,数据获取困难。为此提出基于组合模型对风洞试验六元力进行预测。首先利用SMOTE过采样方法对风洞试验小样本数据进行数据扩充,然后采用极限梯度提升算法(extreme gradient boosting,XGBoost)、K最近邻算法(k-nearest neighbor,KNN)和多层感知器(multilayer perceptron,MLP)3个单一模型建立XGBoost-KNN-MLP组合模型。为克服权重带来的影响,采用人工免疫算法(artificial immune algorithm,AIA)对组合模型的权重系数进行优化建立AIA-XKM组合预测模型。预测效果以平均绝对误差(mean absolute error,MAE)、均方误差(mean square error,MSE)、决定系数(r-square,R2)和均方根误差(root mean squared error,RMSE)为评价指标。并与经典算法XGBoost、KNN、MLP、SVM、RNN构建的预测模型进行对比。实验结果表明,所提出的AIA-XKM组合预测模型在六元力预测中弥补了单一模型存在的不足,在预测精度和泛化能力中表现出更高性能。将该预测模型应用于风洞试验前,能够提前预测试验的输出数值,判断试验的可行性与准确性,提高风洞试验的成功率,减少无用试验。 展开更多
关键词 数据预测 小样本 组合模型 风洞试验
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基于组合赋权和云模型的航空发动机状态评估
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作者 曲春刚 王长乐 《南京航空航天大学学报(自然科学版)》 北大核心 2025年第4期670-680,共11页
为了解决发动机状态评估中状态信息的随机性和模糊性问题,提出了一种基于组合赋权和云模型的航空发动机状态评估方法。经过原理分析、专家经验、相关性分析,对发动机构建层级化指标体系;通过层次分析法和熵权法分别确定其主客观权重,再... 为了解决发动机状态评估中状态信息的随机性和模糊性问题,提出了一种基于组合赋权和云模型的航空发动机状态评估方法。经过原理分析、专家经验、相关性分析,对发动机构建层级化指标体系;通过层次分析法和熵权法分别确定其主客观权重,再通过线性组合赋权法确定组合权重;针对航空发动机确定评价标准等级及其区间,通过相对劣化度映射状态等级评分、云模型进行定性分析和相似度进行定量分析;以A320系列飞机上多台发动机的QAR数据进行分析验证。其中某台使用初期的发动机结果表明:发动机从最初的强离散健康状态趋于弱离散亚健康状态,对应零部件问题的逐渐显露和磨合期趋于稳定的实际情况。因此,基于组合赋权和云模型的航空发动机状态评估模型有效,为识别发动机的状态、了解发动机的长期趋势、采取预防性维修和提高飞行安全性提供有力保障。 展开更多
关键词 航空发动机 状态评估 组合赋权 云模型 QAR数据
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基于LSTM-XGBoost的国产民用飞机燃油流量预测
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作者 杨军利 李立坤 +2 位作者 钱宇 唐盛香 杨沛达 《航空工程进展》 2025年第5期207-214,共8页
神经网络模型已广泛应用于燃油消耗预测,但使用单一模型的预测精度还有待提高。选取影响燃油流量的9个参数进行灰色关联度分析,获取关联度大于0.7的8个参数作为燃油流量的影响参数;对国产民用飞机的快速存取记录器(QAR)数据进行小波变... 神经网络模型已广泛应用于燃油消耗预测,但使用单一模型的预测精度还有待提高。选取影响燃油流量的9个参数进行灰色关联度分析,获取关联度大于0.7的8个参数作为燃油流量的影响参数;对国产民用飞机的快速存取记录器(QAR)数据进行小波变换去噪,得到研究所需要的飞行数据;建立长短期记忆网络(LSTM)预测模型和极端梯度提升(XGBoost)预测模型,使用误差倒数法将两种模型组合起来对飞行数据进行预测,并利用国产民用飞机在某航线的飞行数据进行算例分析。结果表明:利用LSTM-XGBoost组合模型预测的准确率为96.53%,高于单一LSTM模型预测的90.21%、XGBoost模型预测的88.47%和PSO-BP模型的91.23%,预测精度较高。 展开更多
关键词 快速存取记录器数据 长短期记忆网络 极端梯度提升算法 燃油流量 组合预测
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