期刊文献+
共找到2,452篇文章
< 1 2 123 >
每页显示 20 50 100
Quantum Realities and Observer-Dependent Universes: An Advanced Observer Model
1
作者 Joseph Hon Cheung Wong 《Journal of Quantum Information Science》 CAS 2024年第3期69-121,共53页
This paper presents a novel observer model that integrates quantum mechanics, relativity, idealism, and the simulation hypothesis to explain the quantum nature of the universe. The model posits a central server transm... This paper presents a novel observer model that integrates quantum mechanics, relativity, idealism, and the simulation hypothesis to explain the quantum nature of the universe. The model posits a central server transmitting multi-media frames to create observer-dependent realities. Key aspects include deriving frame rates, defining quantum reality, and establishing hierarchical observer structures. The model’s impact on quantum information theory and philosophical interpretations of reality are examined, with detailed discussions on information loss and recursive frame transmission in the appendices. 展开更多
关键词 Quantum Mechanics observer model Frame Rates Quantum Reality Hierarchical observers Information Theory Simulation Hypothesis Recursive Frame Transmission Information Loss
下载PDF
A seismic modeling analysis of wide and narrow 3D observation systems for channel sand bodies 被引量:4
2
作者 狄帮让 徐秀仓 魏建新 《Applied Geophysics》 SCIE CSCD 2008年第4期294-300,共7页
The effect of the wide and narrow azimuth 3D observation systems on seismic imaging precision is becoming a hot area for studies of high precision 3D seismic acquisition methods in recent years. In this paper we utili... The effect of the wide and narrow azimuth 3D observation systems on seismic imaging precision is becoming a hot area for studies of high precision 3D seismic acquisition methods in recent years. In this paper we utilize 3D physical seismic modeling experiments. A 3D channel sand body physical seismic model is constructed and two acquisition systems are designed with wide azimuth (16 lines) and narrow azimuth (8 lines) to model 3D seismic data acquisition and processing seismic work flows. From analysis of migrated time slice data with high quality and small size, we conclude that when the overlying layers are smooth and lateral velocities have little change, both wide and narrow azimuth observation systems in 3D acquisition can be used for obtaining high precision imaging and equivalent resolution of the channel sand body. 展开更多
关键词 Wide and narrow azimuth observation systems seismic imaging physicalseismic modeling time slice RESOLUTION
下载PDF
RBF neural network regression model based on fuzzy observations 被引量:1
3
作者 朱红霞 沈炯 苏志刚 《Journal of Southeast University(English Edition)》 EI CAS 2013年第4期400-406,共7页
A fuzzy observations-based radial basis function neural network (FORBFNN) is presented for modeling nonlinear systems in which the observations of response are imprecise but can be represented as fuzzy membership fu... A fuzzy observations-based radial basis function neural network (FORBFNN) is presented for modeling nonlinear systems in which the observations of response are imprecise but can be represented as fuzzy membership functions. In the FORBFNN model, the weight coefficients of nodes in the hidden layer are identified by using the fuzzy expectation-maximization ( EM ) algorithm, whereas the optimal number of these nodes as well as the centers and widths of radial basis functions are automatically constructed by using a data-driven method. Namely, the method starts with an initial node, and then a new node is added in a hidden layer according to some rules. This procedure is not terminated until the model meets the preset requirements. The method considers both the accuracy and complexity of the model. Numerical simulation results show that the modeling method is effective, and the established model has high prediction accuracy. 展开更多
关键词 radial basis function neural network (RBFNN) fuzzy membership function imprecise observation regression model
下载PDF
The in situ observation of modelled sea ice drift characteristics in the Bohai Sea 被引量:4
4
作者 Yu Yan Wei Gu +1 位作者 Yingjun Xu Qian Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第3期17-25,共9页
Sea ice drift is mainly controlled by ocean currents, local wind, and internal ice stress. Information on sea ice motion, especially in situ synchronous observation of an ice velocity, a current velocity, and a wind s... Sea ice drift is mainly controlled by ocean currents, local wind, and internal ice stress. Information on sea ice motion, especially in situ synchronous observation of an ice velocity, a current velocity, and a wind speed, is of great significance to identify ice drift characteristics. A sea ice substitute, the so-called "modelled ice", which is made by polypropylene material with a density similar to Bohai Sea ice, is used to complete a free drift experiment in the open sea. The trajectories of isolated modelled ice, currents and wind in the Bohai Sea during non-frozen and frozen periods are obtained. The results show that the currents play a major role while the wind plays a minor role in the free drift of isolated modelled ice when the wind is mild in the Bohai Sea. The modelled ice drift is significantly affected by the ocean current and wind based on the ice–current–wind relationship established by a multiple linear regression. The modelled ice velocity calculated by the multiple linear regression is close to that of the in situ observation, the magnitude of the error between the calculated and observed ice velocities is less than12.05%, and the velocity direction error is less than 6.21°. Thus, the ice velocity can be estimated based on the observed current velocity and wind speed when the in situ observed ice velocity is missing. And the modelled ice of same thickness with a smaller density is more sensitive to the current velocity and the wind speed changes. In addition, the modelled ice drift characteristics are shown to be close to those of the real sea ice, which indicates that the modelled ice can be used as a good substitute of real ice for in situ observation of the free ice drift in the open sea, which helps solve time availability, safety and logistics problems related to in situ observation on real ice. 展开更多
关键词 Bohai SEA modelled ICE in SITU observation SEA ICE DRIFT
下载PDF
Experimental Model and Analytic Solution for Real-time Observation of Vehicle's Additional Steer Angle 被引量:3
5
作者 ZHANG Xiaolong LI Liang +2 位作者 PAN Deng CAO Chengmao SONG Jian 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第2期340-347,共8页
The current research of real-time observation for vehicle roll steer angle and compliance steer angle(both of them comprehensively referred as the additional steer angle in this paper) mainly employs the linear vehi... The current research of real-time observation for vehicle roll steer angle and compliance steer angle(both of them comprehensively referred as the additional steer angle in this paper) mainly employs the linear vehicle dynamic model, in which only the lateral acceleration of vehicle body is considered. The observation accuracy resorting to this method cannot meet the requirements of vehicle real-time stability control, especially under extreme driving conditions. The paper explores the solution resorting to experimental method. Firstly, a multi-body dynamic model of a passenger car is built based on the ADAMS/Car software, whose dynamic accuracy is verified by the same vehicle's roadway test data of steady static circular test. Based on this simulation platform, several influencing factors of additional steer angle under different driving conditions are quantitatively analyzed. Then ε-SVR algorithm is employed to build the additional steer angle prediction model, whose input vectors mainly include the sensor information of standard electronic stability control system(ESC). The method of typical slalom tests and FMVSS 126 tests are adopted to make simulation, train model and test model's generalization performance. The test result shows that the influence of lateral acceleration on additional steer angle is maximal (the magnitude up to 1°), followed by the longitudinal acceleration-deceleration and the road wave amplitude (the magnitude up to 0.3°). Moreover, both the prediction accuracy and the calculation real-time of the model can meet the control requirements of ESC This research expands the accurate observation methods of the additional steer angle under extreme driving conditions. 展开更多
关键词 VEHICLE ADAMS model additional steer SVM real-time observation
下载PDF
ASYMPTOTIC NORMALITY OF PARAMETERSESTIMATION IN EV MODEL WITH REPLICATEDOBSERVATIONS 被引量:3
6
作者 张三国 陈希孺 《Acta Mathematica Scientia》 SCIE CSCD 2002年第1期107-114,共8页
This paper based on the essay [1], studies in case that replicated observations are available in some experimental points., the parameters estimation of one dimensional linear errors-in-variables (EV) models. Asymptot... This paper based on the essay [1], studies in case that replicated observations are available in some experimental points., the parameters estimation of one dimensional linear errors-in-variables (EV) models. Asymptotic normality is established. 展开更多
关键词 errors-in-variables model asymptotic normality replicated observations
下载PDF
Evaluation of Simulated CO_2 Concentrations from the CarbonTracker-Asia Model Using In-situ Observations over East Asia for 2009–2013 被引量:2
7
作者 Samuel Takele KENEA Young-Suk OH +6 位作者 Jae-Sang RHEE Tae-Young GOO Young-Hwa BYUN Shanlan LI Lev D.LABZOVSKII Haeyoung LEE Robert F.BANKS 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第6期603-613,共11页
The CarbonTracker(CT) model has been used in previous studies for understanding and predicting the sources, sinks, and dynamics that govern the distribution of atmospheric CO_2 at varying ranges of spatial and tempora... The CarbonTracker(CT) model has been used in previous studies for understanding and predicting the sources, sinks, and dynamics that govern the distribution of atmospheric CO_2 at varying ranges of spatial and temporal scales. However, there are still challenges for reproducing accurate model-simulated CO_2 concentrations close to the surface, typically associated with high spatial heterogeneity and land cover. In the present study, we evaluated the performance of nested-grid CT model simulations of CO_2 based on the CT2016 version through comparison with in-situ observations over East Asia covering the period 2009–13. We selected sites located in coastal, remote, inland, and mountain areas. The results are presented at diurnal and seasonal time periods. At target stations, model agreement with in-situ observations was varied in capturing the diurnal cycle. Overall, biases were less than 6.3 ppm on an all-hourly mean basis, and this was further reduced to a maximum of 4.6 ppm when considering only the daytime. For instance, at Anmyeondo, a small bias was obtained in winter, on the order of 0.2 ppm. The model revealed a diurnal amplitude of CO_2 that was nearly flat in winter at Gosan and Anmyeondo stations, while slightly overestimated in the summertime. The model's performance in reproducing the diurnal cycle remains a challenge and requires improvement. The model showed better agreement with the observations in capturing the seasonal variations of CO_2 during daytime at most sites, with a correlation coefficient ranging from 0.70 to 0.99. Also, model biases were within-0.3 and 1.3 ppm, except for inland stations(7.7 ppm). 展开更多
关键词 model EVALUATION in-situ observations CarbonTracker EAST ASIA
下载PDF
A modified stochastic model for LS+AR hybrid method and its application in polar motion short-term prediction 被引量:1
8
作者 Fei Ye Yunbin Yuan 《Geodesy and Geodynamics》 EI CSCD 2024年第1期100-105,共6页
Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currentl... Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currently,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM prediction.Besides,the weighted LS+AR hybrid method performs well for PM short-term prediction.However,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR model.In this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid method.By using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid method.Compared to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,respectively.Besides,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods. 展开更多
关键词 Stochastic model LS+AR Short-term prediction The earth rotation parameter(ERP) observation model
下载PDF
Pattern-Moving-Based Parameter Identification of Output Error Models with Multi-Threshold Quantized Observations 被引量:2
9
作者 Xiangquan Li Zhengguang Xu +1 位作者 Cheng Han Ning Li 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第3期1807-1825,共19页
This paper addresses a modified auxiliary model stochastic gradient recursive parameter identification algorithm(M-AM-SGRPIA)for a class of single input single output(SISO)linear output error models with multi-thresho... This paper addresses a modified auxiliary model stochastic gradient recursive parameter identification algorithm(M-AM-SGRPIA)for a class of single input single output(SISO)linear output error models with multi-threshold quantized observations.It proves the convergence of the designed algorithm.A pattern-moving-based system dynamics description method with hybrid metrics is proposed for a kind of practical single input multiple output(SIMO)or SISO nonlinear systems,and a SISO linear output error model with multi-threshold quantized observations is adopted to approximate the unknown system.The system input design is accomplished using the measurement technology of random repeatability test,and the probabilistic characteristic of the explicit metric value is employed to estimate the implicit metric value of the pattern class variable.A modified auxiliary model stochastic gradient recursive algorithm(M-AM-SGRA)is designed to identify the model parameters,and the contraction mapping principle proves its convergence.Two numerical examples are given to demonstrate the feasibility and effectiveness of the achieved identification algorithm. 展开更多
关键词 Pattern moving multi-threshold quantized observations output error model auxiliary model parameter identification
下载PDF
Preliminary results on kinematic model of tectonic blocks derived from high precision GPS observations in Southwest China 被引量:1
10
作者 黄立人 马青 +2 位作者 朱文耀 程宗颐 熊永清 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第1期27-34,共8页
In the paper, the kinematic model of tectonic blocks in southwest China is studied based on the precision GPS observations carried out under the major subject of 'Studies on Current Crustal Movement and Geodynamic... In the paper, the kinematic model of tectonic blocks in southwest China is studied based on the precision GPS observations carried out under the major subject of 'Studies on Current Crustal Movement and Geodynamics' which belongs to the State Climbing Project. It is believed that at present, the data of high precision GPS observation may provide convincing information related to the horizontal movement of tectonic blocks in the Chinese mainland. The preliminary results obtained from the kinematic model have given some direct evidences for the research of dynamic mechanism of crustal deformation in the Chinese mainland and on the basis of which, the kinematic characteristics and their relations to the seismicity and seismic risk in the reobserved region are analysed. The preliminary observation results are encouraging. 展开更多
关键词 GPS observation Southwest China tectonic block kinematic model
下载PDF
Modified Observation Model in Tightly-Coupled INS/GPS Integration 被引量:1
11
作者 Guochao Fan Dan Song Chengdong Xu 《Journal of Beijing Institute of Technology》 EI CAS 2017年第1期16-28,共13页
The conventional Kalman filter(CKF)is widely used in tightly-coupled INS/GPS integrated navigation systems.The linearization accuracy of the CKF observation model is one of the decisive factors of the estimation acc... The conventional Kalman filter(CKF)is widely used in tightly-coupled INS/GPS integrated navigation systems.The linearization accuracy of the CKF observation model is one of the decisive factors of the estimation accuracy and therefore navigation accuracy.Additionally,the conventional observation model(COM)used by the filter may be divergent,which would result into some terrible accuracies of INS/GPS integration navigation in some cases.To improve the navigation accuracy,the linearization accuracy of the COM still needs further improvement.To deal with this issue,the observation model is modified with the linearization of the range and range rate equations in this paper.Compared with COM,the modified observation model(MOM)further considers the difference between the real user position and the position calculated by SINS.To verify the advantages of this model,INS/GPS integrated navigation simulation experiments are conducted with the usage of COM and MOM respectively.According to the simulation results,the positions(velocities)calculated using COM are divergent over time while the others using MOM are convergent,which demonstrates the higher linearization accuracy of MOM. 展开更多
关键词 INS/GPS integration LINEARIZATION modified observation model (MOM) conventionalobservation model (COM)
下载PDF
Design of task priority model and algorithm for imaging observation problem 被引量:2
12
作者 WU Jian LU Fang +2 位作者 ZHANG Jiawei YANG Jinghui XING Lining 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第2期321-334,共14页
In the imaging observation system, imaging task scheduling is an important topic. Most scholars study the imaging task scheduling from the perspective of static priority, and only a few from the perspective of dynamic... In the imaging observation system, imaging task scheduling is an important topic. Most scholars study the imaging task scheduling from the perspective of static priority, and only a few from the perspective of dynamic priority. However,the priority of the imaging task is dynamic in actual engineering. To supplement the research on imaging observation, this paper proposes the task priority model, dynamic scheduling strategy and Heuristic algorithm. At first, this paper analyzes the relevant theoretical basis of imaging observation, decomposes the task priority into four parts, including target priority, imaging task priority, track, telemetry & control(TT&C)requirement priority and data transmission requirement priority, summarizes the attribute factors that affect the above four types of priority in detail, and designs the corresponding priority model. Then, this paper takes the emergency tasks scheduling problem as the background, proposes the dynamic scheduling strategy and heuristic algorithm. Finally, the task priority model,dynamic scheduling strategy and heuristic algorithm are verified by experiments. 展开更多
关键词 IMAGING observation system IMAGING TASK PRIORITY TASK PRIORITY model dynamic SCHEDULING strategy HEURISTIC algorithm
下载PDF
Observations of Passenger Flow and Verification of a Crowd Dynamics Model
13
作者 YUAN Jianping FANG Zheng +2 位作者 LO Siuming XIE Lilin HUANG Danguang 《Wuhan University Journal of Natural Sciences》 CAS 2008年第2期195-200,共6页
This paper reports observations of passenger flow in the Wuchang railway station in Wuhan, China during the Chinese Traditional Spring Festival in 2006. The data collected are used to verify a crowd dynamics model pre... This paper reports observations of passenger flow in the Wuchang railway station in Wuhan, China during the Chinese Traditional Spring Festival in 2006. The data collected are used to verify a crowd dynamics model previously developed. The crowd dynamics model is based on simulating the global movement of each individual under the influence of the surrounding crowd, and the good agreement between the predictions and observations validates the prediction model. The crowd dynamics model suggests that the crowd movement speed is dominated by two factors: the front-back inter-person effect, and the pedestrian's self-motive. The first effect gives logarithmic relationship between the crowd speed and crowd density. The second factor depends on the individual motive driven with which people try to divorce themselves from the control of the crowd movement. The prediction model are helpful to guide the design of public traffic systems for effective crowd dispersal. 展开更多
关键词 crowd dynamics model observation mathematical modeling EVACUATION traffic planning
下载PDF
Disturbance rejection tube model predictive levitation control of maglev trains
14
作者 Yirui Han Xiuming Yao Yu Yang 《High-Speed Railway》 2024年第1期57-63,共7页
Magnetic levitation control technology plays a significant role in maglev trains.Designing a controller for the levitation system is challenging due to the strong nonlinearity,open-loop instability,and the need for fa... Magnetic levitation control technology plays a significant role in maglev trains.Designing a controller for the levitation system is challenging due to the strong nonlinearity,open-loop instability,and the need for fast response and security.In this paper,we propose a Disturbance-Observe-based Tube Model Predictive Levitation Control(DO-TMPLC)scheme combined with a feedback linearization strategy for the levitation system.The proposed strategy incorporates state constraints and control input constraints,i.e.,the air gap,the vertical velocity,and the current applied to the coil.A feedback linearization strategy is used to cancel the nonlinearity of the tracking error system.Then,a disturbance observer is implemented to actively compensate for disturbances while a TMPLC controller is employed to alleviate the remaining disturbances.Furthermore,we analyze the recursive feasibility and input-to-state stability of the closed-loop system.The simulation results indicate the efficacy of the proposed control strategy. 展开更多
关键词 Maglev trains Levitation system Constrained control Disturbance observer model predictive control
下载PDF
Experimental Observation of the Ground-State Geometric Phase of Three-Spin XY Model
15
作者 周辉 李兆凯 +3 位作者 王恒岩 陈宏伟 彭新华 杜江峰 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第6期1-5,共5页
The geometric phase has become a fundamental concept in many fields of physics since it was revealed. Recently, the study of the geometric phase has attracted considerable attention in the context of quantum phase tra... The geometric phase has become a fundamental concept in many fields of physics since it was revealed. Recently, the study of the geometric phase has attracted considerable attention in the context of quantum phase transition, where the ground state properties of the system experience a dramatic change induced by a variation of an external parameter. In this work, we experimentally measure the ground-state geometric phase of the three-spin XY model by utilizing the nuclear magnetic resonance technique. The experimental results indicate that the geometric phase could be used as a fingerprint of the ground-state quantum phase transition of many-body systems. 展开更多
关键词 of on it in Experimental observation of the Ground-State Geometric Phase of Three-Spin XY model is been that
下载PDF
Design and Application of Integrated Monitoring Model for Provincial Meteorological Observation Data Transmission
16
作者 Yonghua Zhang Xiaoyu Chen +3 位作者 Shuoben Bi Ping Shen Zhenlang Ao Zhongying Hu 《Journal of Geoscience and Environment Protection》 2019年第5期94-104,共11页
With the development of meteorological services, there are more and more types of real-time observation data, and the timeliness requirements are getting higher and higher. The monitoring methods of existing meteorolo... With the development of meteorological services, there are more and more types of real-time observation data, and the timeliness requirements are getting higher and higher. The monitoring methods of existing meteorological observation data transmission can no longer meet the needs. This paper proposes a new monitoring model, namely the “integrated monitoring model” for provincial meteorological observation data transmission. The model can complete the whole network monitoring of meteorological observation data transmission process. Based on this model, the integrated monitoring system for meteorological observation data transmission in Guangdong Province is developed. The system uses Java as the programming language, and integrates J2EE, Hibernate, Quartz, Snmp4j and Slf4j frameworks, and uses Oracle database as the data storage carrier, following the MVC specification and agile development concept. The system development uses four key technologies, including simple network management protocol, network connectivity detection technology, remote host management technology and thread pool technology. The integrated monitoring system has been put into business application. As a highlight of Guangdong’s meteorological modernization, it has played an active role in many major meteorological services. 展开更多
关键词 PROVINCIAL Level METEOROLOGICAL observation Data Transmission INTEGRATED Monitoring model DESIGN SNMP
下载PDF
Applying the Distributed Hydrological Model for Tropical Monsoon Basins by Using Earth Observation Data (Case Studies: Kone and Ba River Basins)
17
作者 Phan Thi Thanh Hang 《Journal of Geoscience and Environment Protection》 2019年第1期23-37,共15页
Due to the limitation of data sources, the application of Distributed Hydrological Models (DHMs) using earth observation data to research water resources is necessary. In this study, the BTOPMC (Block-wise use of TOPM... Due to the limitation of data sources, the application of Distributed Hydrological Models (DHMs) using earth observation data to research water resources is necessary. In this study, the BTOPMC (Block-wise use of TOPMODEL) model was applied for 2 basins in the tropical monsoon region. This is the first time that the land cover map of the CCI (Climate Change Initiative Land Cover Team) was prepared for input data instead of IGBP (International Geosphere-Biosphere Programme) land cover map as proposed in the demo version of the BTOPMC model. The calibration and validation results showed that the Nash-Sutcliffe coefficients for daily stream discharge were 77.5% and 68.7% at Cung Son station (Ba basin). The Nash-Sutcliffe coefficients for daily stream discharge were 79.4% and 69.0% at Binh Tuong station (Kone basin), respectively. Because of a stop in measuring the discharge at Binh Tuong station in 2007, this model was applied to simulate discharge during the period of 2008-2015. Furthermore, the effect of land cover on discharge at Cung Son station was considered. The annual discharge in 2010 at Cung Son decreased 8 m3/s in the comparison between two scenarios (land cover of 2000 and 2010). According to this result, it is possible to propose a wide application range of the DHMs model to the tropical monsoon river basins using earth observation data. 展开更多
关键词 Distributed HYDROLOGICAL model TROPICAL MONSOON DISCHARGE Land COVER Earth observation Data
下载PDF
Using Residual Estimators to Detect Outliers and Potential Controlling Observations in Structural Equation Modelling: QQ Plot Approach
18
作者 A. R. Abdul-Aziz Albert Luguterah Bashiru I. I. Saeed 《Open Journal of Statistics》 2020年第5期905-914,共10页
The structural equation model (SEM) concept is generally influenced by the presence of outliers and controlling variables. To a very large extent, this could have consequential effects on the parameters and the model ... The structural equation model (SEM) concept is generally influenced by the presence of outliers and controlling variables. To a very large extent, this could have consequential effects on the parameters and the model fitness. Though previous researches have studied outliers and controlling observations from various perspectives including the use of box plots, normal probability plots, among others, the use of uniform horizontal QQ plot is yet to be explored. This study is, therefore, aimed at applying uniform QQ plots to identifying outliers and possible controlling observations in SEM. The results showed that all the three methods of estimators manifest the ability to identify outliers and possible controlling observations in SEM. It was noted that the Anderson-Rubin estimator of QQ plot showed a more efficient or visual display of spotting outliers and possible controlling observations as compared to the other methods of estimators. Therefore, this paper provides an efficient way identifying outliers as it fragments the data set. 展开更多
关键词 OUTLIERS Controlling observations ESTIMATORS QQ Plots Structural Equation modelling
下载PDF
Establishment and application of the anisotropic shale-rock physical model in the observation coordinate system
19
作者 Gui Jun-Chuan Sang Yu +5 位作者 Guo Jian-Chun Zeng Bo Song Yi Huang Hao-Yong Xu Er-si Chen Ya-xi 《Applied Geophysics》 SCIE CSCD 2022年第3期325-342,470,共19页
No shale-rock physical model has been established in the observation coordinate system.To this end,this paper carried out anisotropic wave velocity tests on shale rock and compared the Thomsen,Daley,and Berryman solut... No shale-rock physical model has been established in the observation coordinate system.To this end,this paper carried out anisotropic wave velocity tests on shale rock and compared the Thomsen,Daley,and Berryman solutions to characterize anisotropic acoustic wave velocity.Finally,the Daley solution was selected.Based on basic rock physical models,such as SCA and DEM methods,and combined with the Daley solution,an anisotropic shale-rock physical model was established in the observation coordinate system and applied in Well B1 in the Luzhou area,Sichuan Basin.Our research conclusions were as follows:1.for the samples from the same core,the P-wave velocities in three directions were in the order VP11>VP45>VP33,shear wave velocity VS11 was the largest,but VS33 and VS45 did not follow the law of Vs33>Vs45 for some samples;2.the Daley solution,which not only considers the accuracy requirements but also has a complete expression of P-,SV-,and SH-waves,is most suitable for characterization of anisotropic wave velocity in this study area;3.the rock physical model constructed in the observation coordinate system has high accuracy,in which the absolute value of the relative error of the P-wave slowness was between 0%and 5.05%(0.55%on average),and that of shear-wave slowness was between 0%and 6.05%(0.59%on average);4.the acoustic waves recorded in Well B1 in the observation coordinate system were very different from those in the constitutive coordinate system.The relative difference of the P-wave was between 6.76%and 30.84%(14.68%on average),and that of the S-wave was between 7.00%and 23.44%(13.99%on average).The acoustic slowness measured in the observation coordinate system,such as in a deviated well or a horizontal well section,must be converted to the constitutive coordinate system before it can be used in subsequent engineering applications;5.the anisotropic shale-rock physical model built in the observation coordinate system proposed in this paper can provide basic data and guidance for subsequent pore pressure prediction,geomechanical modeling,and fracturing stimulation design for deviated and horizontal wells. 展开更多
关键词 shale anisotropy wave velocity test observation coordinate system constitutive coordinate system rock physical model
下载PDF
The 9–11 November 2013 Explosive Cyclone over the Japan Sea- Okhotsk Sea: Observations and WRF Modeling Analyses
20
作者 FU Gang JING Miaomiao LI Pengyuan 《Journal of Ocean University of China》 SCIE CAS CSCD 2020年第5期989-1004,共16页
During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when... During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward.It had a minimum sea level pressure of 959.0 hPa,a significant deepening rate of central pressure of 2.9 Bergeron,and a maximum instantaneous wind speed of 42.7 m s−1.This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting(WRF)modeling results.The evolutionary processes of this EC were examined by using Final Analyses(FNL)data,Multi-Functional Transport Satellites-1R(MTSAT-1R)data,upper observation data and surface observation data.WRF-3.5 modeling results were also used to examine the development mechanism of this EC.It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC. 展开更多
关键词 explosive cyclone the Japan Sea-Okhotsk Sea observationS WRF-3.5 modeling results potential vorticity
下载PDF
上一页 1 2 123 下一页 到第
使用帮助 返回顶部