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Establishment and application of service mapping model for proactive remanufacturing impeller 被引量:2
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作者 宋守许 邰莹莹 柯庆镝 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第12期3143-3152,共10页
Since the complex impeller structure and the difficult remanufacturing process may easily cause advance remanufacturing or excessive use,an optimized design method of impeller and service mapping model was presented f... Since the complex impeller structure and the difficult remanufacturing process may easily cause advance remanufacturing or excessive use,an optimized design method of impeller and service mapping model was presented for its proactive remanufacturing with setting up to explore the best remanufacturing time point in this work.Considering a certain model of long distance pipeline compressor impeller with the Basquin equation and the design method of impeller,the mathematical relationship between the changes of structure and life of the impeller was established.And the service mapping model between the structure and life was set up and simulated by ANSYS software.Thus,the service mapping model was applied to feedback the original design for proactive remanufacturing.In this work,the best proactive remanufacturing time point of impeller was analyzed with the service mapping model,and the structural parameter values could be optimized at this time point.Meanwhile,in the results of this simulation,it proves that the impeller under this optimization performance could satisfy the impeller operating demands.Therefore,comparing with the traditional optimization design method,the remanufacturing optimized design based on the service mapping model is feasible in proactive remanufacturing for sustainable development. 展开更多
关键词 IMPELLER proactive remanufacturing remanufacturing time point service mapping model
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HYPERSTATIC STRUCTURE MAPPING MODEL BUILDING AND OPTIMIZING DESIGN 被引量:2
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作者 XU Gening GAO Youshan +1 位作者 ZHANG Xueliang YANG Ruigang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第1期55-59,共5页
Hyperstatic structure plane model being built by structural mechanics is studied. Space model precisely reflected in real stress of the structure is built by finite element method (FEM) analysis commerce software. M... Hyperstatic structure plane model being built by structural mechanics is studied. Space model precisely reflected in real stress of the structure is built by finite element method (FEM) analysis commerce software. Mapping model of complex structure system is set up, with convenient calculation just as in plane model and comprehensive information as in space model. Plane model and space model are calculated under the same working condition. Plane model modular construction inner force is considered as input data; Space model modular construction inner force is considered as output data. Thus specimen is built on input data and output dam. Character and affiliation are extracted through training specimen, with the employment of nonlinear mapping capability of the artificial neural network. Mapping model with interpolation and extrpolation is gained, laying the foundation for optimum design. The steel structure of high-layer parking system (SSHLPS) is calculated as an instance. A three-layer back-propagation (BP) net including one hidden layer is constructed with nine input nodes and eight output nodes for a five-layer SSHLPS. The three-layer structure optimization result through the mapping model interpolation contrasts with integrity re-analysis, and seven layers structure through the mapping model extrpulation contrasts with integrity re-analysis. Any layer SSHLPS among 1-8 can be calculated with much accuracy. Amount of calculation can also be reduced if it is appfied into the same topological structure, with reduced distortion and assured precision. 展开更多
关键词 Plane model - Space model Artificial neural networks mapping model Optimum design
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Kinematic-mapping-model-guided analysis and optimization of 2-PSS&1-RR circular-rail parallel mechanism for fully steerable phased array antennas
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作者 Guodong Tan Xiangfei Meng +4 位作者 Xuechao Duan Lulu Cheng Dingchao Niu Shuai He Dan Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第8期136-154,共19页
This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1-RR circular-rail parallel mechanism. In... This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1-RR circular-rail parallel mechanism. Initially, a comparative motion analysis between the 3D model of the mount and its full-scale prototype is conducted to validate effectiveness. Given the inherent complexity, a kinematic mapping model is established between the mount and the crank-slider linkage, providing a guiding framework for subsequent analysis and optimization. Guided by this model, feasible inverse and forward solutions are derived, enabling precise identification of stiffness singularities. The concept of singularity distance is thus introduced to reflect the structural stiffness of the mount. Subsequently, also guided by the mapping model, a heuristic algorithm incorporating two backtracking procedures is developed to reduce the mount's mass. Additionally, a parametric finite-element model is employed to explore the relation between singularity distance and structural stiffness. The results indicate a significant reduction(about 16%) in the antenna mount's mass through the developed algorithm, while highlighting the singularity distance as an effective stiffness indicator for this type of antenna mount. 展开更多
关键词 Innovative antenna mount Circular rail Kinematic mapping model Crank-slider linkage Stiffness singularity BACKTRACKING
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Team effectiveness evaluation and virtual reality scenario mapping model for helicopter emergency rescue 被引量:5
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作者 Xue SUN Hu LIU +2 位作者 Yongliang TIAN Guanghui WU Yuan GAO 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2020年第12期3306-3317,共12页
The application of helicopter emergency rescue is becoming increasingly widespread,but the flight crew training in this area is still difficult due to high cost and risk.Nevertheless,with the development of Virtual Re... The application of helicopter emergency rescue is becoming increasingly widespread,but the flight crew training in this area is still difficult due to high cost and risk.Nevertheless,with the development of Virtual Reality(VR)technology,virtual simulation has become a significant role in crew training of helicopter rescue.During the implementation of VR-based training,how to transform complex real tasks into VR scenarios and how to evaluate the performance of crew are of great importance.To address these issues,a novel VR-based R-E-A-D(Report,Evaluate,Agree,Do)evaluation model for training is proposed,which is suitable for complex missions with multiple tasks,multiple scenarios,and multiple people.Then,a mapping method of VR scenarios is put forward,which can transform the real tasks into virtual scenarios to serve the virtual simulation training.Finally,an experiment is carried out to verify the feasibility of the evaluation method and virtual scenario mapping method. 展开更多
关键词 Helicopter emergency rescue Scenario mapping model Team effectiveness evaluation Virtual reality(VR) Virtual simulation-based training
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Monthly Mean Temperature Prediction Based on a Multi-level Mapping Model of Neural Network BP Type 被引量:1
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作者 严绍瑾 彭永清 郭光 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1995年第2期225-232,共8页
In terms of 34-year monthly mean temperature series in 1946-1979,the multi-level maPPing model of neural netWork BP type was applied to calculate the system's fractual dimension Do=2'8,leading tO a three-level... In terms of 34-year monthly mean temperature series in 1946-1979,the multi-level maPPing model of neural netWork BP type was applied to calculate the system's fractual dimension Do=2'8,leading tO a three-level model of this type with ixj=3x2,k=l,and the 1980 monthly mean temperture predichon on a long-t6rm basis were prepared by steadily modifying the weighting coefficient,making for the correlation coefficient of 97% with the measurements.Furthermore,the weighhng parameter was modified for each month of 1980 by means of observations,therefore constrcuhng monthly mean temperature forecasts from January to December of the year,reaching the correlation of 99.9% with the measurements.Likewise,the resulting 1981 monthly predictions on a long-range basis with 1946-1980 corresponding records yielded the correlahon of 98% and the month-tO month forecasts of 99.4%. 展开更多
关键词 Neural netWork BP-type multilevel mapping model Monthly mean temperature prediction
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Building a Post-Layout Simulation Performance Model with Global Mapping Model Fusion Technique
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作者 Zhikai Wang Wenfei Hu +4 位作者 Sen Yin Ruitao Wang Jian Zhang Yan Wang Zuochang Ye 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2022年第3期512-525,共14页
Building a post-layout simulation performance model is essential in closing the loop of analog circuits, but it is a challenging task because of the high-dimensional space and expensive simulation cost. To facilitate ... Building a post-layout simulation performance model is essential in closing the loop of analog circuits, but it is a challenging task because of the high-dimensional space and expensive simulation cost. To facilitate efficient modeling, this paper proposes a Global Mapping Model Fusion(GMMF) technique. The key idea of GMMF is to reuse the schematic-level model trained by the Artificial Neural Network(ANN) algorithm, and combine it with few mapping coefficients to build the post-simulation model. Furthermore, as an efficient global optimization algorithm,differential evolution is applied to determine the optimal mapping coefficients with few samples. In GMMF, only a small number of mapping coefficients are unknown, so the number of post-layout samples needed is significantly reduced. To enhance practical utility of the proposed GMMF technique, two specific mapping relations, i.e., linear or weakly no-linear and nonlinear, are carefully considered in this paper. We conduct experiments on two topologies of two-stage operational amplifier and comparator in different commercial processes. All the simulation data for modeling are obtained from a parametric design framework. A more than 5 runtime speedup is achieved over ANN without surrendering any accuracy. 展开更多
关键词 post-layout simulation performance model Global mapping model Fusion(GMMF) Artificial Neural Network(ANN) few mapping coefficients differential evolution
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MODELING METHOD FOR PRODUCT STRUCTURE MAPPING BASED ON REVERSE SOLVING OF LOCUS AND MOTION 被引量:3
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作者 ZHANG Shuyou YI Guodong XU Xiaofeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第5期114-119,共6页
Aiming at the problem of structure design in reverse-design of mechanism, a structure mapping method based on reverse solving of locus and motion (RSLM) is presented. The mechanism scheme meeting the requirements of... Aiming at the problem of structure design in reverse-design of mechanism, a structure mapping method based on reverse solving of locus and motion (RSLM) is presented. The mechanism scheme meeting the requirements of geometric and structural features is obtained through RSLM. The element instance subsets related to component are established based on the element type mapping, pair structure type mapping and design knowledge mapping between components and elements layer by layer. The assembly position mapping of elements is established based on the topological structure information of mechanism scheme, and the product modeling of structure mapping is realized. The algorithm program and prototype system of product structure mapping based on RSLM are developed. Application samples show that the method implements the integration of scheme design, assembly design and structure design, and modeling for product structure mapping based on RSLM. The feasibility of assembly is analyzed in scheme design that contributes to reducing the design error, and raising the design efficiency and quality. 展开更多
关键词 Reverse solving mapping Mechanism Assembly modeling
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The non-stationary and spatially varying associations between hand,foot and mouth disease and multiple environmental factors:A Bayesian spatiotemporal mapping model study
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作者 Li Shen Minghao Sun +4 位作者 Mengna Wei Qingwu Hu Yao Bai Zhongjun Shao Kun Liu 《Infectious Disease Modelling》 2024年第2期373-386,共14页
The transmission and prevalence of Hand,Foot and Mouth Disease(HFMD)are affected by a variety of natural and socio-economic environmental factors.This study aims to quantitatively investigate the non-stationary and sp... The transmission and prevalence of Hand,Foot and Mouth Disease(HFMD)are affected by a variety of natural and socio-economic environmental factors.This study aims to quantitatively investigate the non-stationary and spatially varying associations between various environmental factors and HFMD risk.We collected HFMD surveillance cases and a series of relevant environmental data from 2013 to 2021 in Xi'an,Northwest China.By controlling the spatial and temporal mixture effects of HFMD,we constructed a Bayesian spatiotemporal mapping model and characterized the impacts of different driving factors into global linear,non-stationary and spatially varying effects.The results showed that the impact of meteorological conditions on HFMD risk varies in both type and magnitude above certain thresholds(temperature:30°C,precipitation:70 mm,solar radiation:13000 kJ/m^(2),pressure:945 hPa,humidity:69%).Air pollutants(PM_(2.5),PM_(10),NO_(2))showed an inverted U-shaped relationship with the risk of HFMD,while other air pollutants(O_(3),SO_(2))showed nonlinear fluctuations.Moreover,the driving effect of increasing temperature on HFMD was significant in the 3-year period,while the inhibitory effect of increasing precipitation appeared evident in the 5-year period.In addition,the proportion of urban/suburban/rural area had a strong influence on HFMD,indicating that the incidence of HFMD firstly increased and then decreased during the rapid urbanization process.The influence of population density on HFMD was not only limited by spatial location,but also varied between high and low intervals.Higher road density inhibited the risk of HFMD,but higher night light index promoted the occurrence of HFMD.Our findings further demonstrated that both ecological and socioeconomic environmental factors can pose multiple driving effects on increasing the spatiotemporal risk of HFMD,which is of great significance for effectively responding to the changes in HFMD epidemic outbreaks. 展开更多
关键词 Hand foot and mouth disease(HFMD) Environmental factors Bayesian spatiotemporal mapping model Non-stationary effects Spatially varying effects
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Neuroid BP-type Model Applied to the Study of Monthly Rainfall Forecasting
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作者 严绍瑾 彭永清 郭光 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1995年第3期335-342,共8页
A neuroid BP-type three-layer mapping model is used for monthly rainfall forecasting in terms of 1946-1985Naming monthly precipitation records as basic sequences and the model has the form i×j=8×3, K=1; by s... A neuroid BP-type three-layer mapping model is used for monthly rainfall forecasting in terms of 1946-1985Naming monthly precipitation records as basic sequences and the model has the form i×j=8×3, K=1; by steadilymodifying the weighing coefficient, long-range monthly forecasts for January to December, 1986 are constructed and1986 month-to-month predictions are made based on, say, the January measurement for February rainfall and soon, with mean absolute error reaching 6,07 and 5,73 mm, respectively. Also, with a different monthly initial value forJune through September, 1994, neuroid forecasting is done,indicating the same result of the drought in Naming during the summer, an outcome that is in sharp agreement with the observation. 展开更多
关键词 Neuroid BP-type three-layer mapping model Monthly rainfall forecasting
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Feedback control scheme of traffic jams based on the coupled map car-following model 被引量:6
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作者 周桐 孙棣华 +1 位作者 赵敏 李华民 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第9期203-208,共6页
Based on the pioneering work of Konishi et al. [Phys. Rev. E (1999) 60 4000], a new feedback control scheme is presented to suppress traffic jams based on the coupled map car-following model under the open boundary ... Based on the pioneering work of Konishi et al. [Phys. Rev. E (1999) 60 4000], a new feedback control scheme is presented to suppress traffic jams based on the coupled map car-following model under the open boundary condition. The effect of the safe headway on the traffic system is considered. According to the control theory, the condition under which traffic jams can be suppressed is analyzed. The results are compared with the previous results concerning congestion control. The simulations show that the suppression performance of our scheme on traffic jams is better than those of the previous schemes, although all the schemes can suppress traffic jams. The simulation results are consistent with theoretical analyses. 展开更多
关键词 traffic jam coupled map car-following model control scheme safe headway
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A new coupled map car-following model considering drivers' steady desired speed 被引量:6
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作者 周桐 孙棣华 +1 位作者 李华民 刘卫宁 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第5期41-45,共5页
Based on the pioneering work of Konishi et al., in consideration of the influence of drivers' steady desired speed ef/ect on the traffic flow, we develop a new coupled map car-following model in the real world. By us... Based on the pioneering work of Konishi et al., in consideration of the influence of drivers' steady desired speed ef/ect on the traffic flow, we develop a new coupled map car-following model in the real world. By use of the control theory, the stability condition of our model is derived. The validity of the present theoretical scheme is verified via numerical simulation, confirming the correctness of our theoretical analysis. 展开更多
关键词 traffic flow traffic congestion coupled map car-following model steady desired speed effect
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A control method for congested traffic in the coupled map car-following model 被引量:5
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作者 沈飞英 葛红霞 +2 位作者 张辉 余寒梅 雷丽 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第10期4208-4216,共9页
Based on the pioneer work of Konishi et al, a new control method is presented to suppress the traffic congestion in the coupled map (CM) car-following model under an open boundary. A control signal concluding the ve... Based on the pioneer work of Konishi et al, a new control method is presented to suppress the traffic congestion in the coupled map (CM) car-following model under an open boundary. A control signal concluding the velocity differences of the two vehicles in front is put forward. The condition under which the traffic jam can be contained is analyzed. The results axe compared with that presented by Konishi et al [Phys. Rev. 1999 E 60 4000-4007]. The simulation results show that the temporal behavior obtained by our method is better than that by the Konishi's et al. method, although both the methods could suppress the traffic jam. The simulation results are consistent with the theoretical analysis. 展开更多
关键词 traffic flow the coupled map car-following model feedback control
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A new coupled-map car-following model based on a transportation supernetwork framework 被引量:2
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作者 姚静 黄婧祎 +1 位作者 陈关荣 许维胜 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第6期141-149,共9页
A new car-following model is proposed by considering information from a number of preceding vehicles with intervehicle communication. A supernetwork architecture is first described, which has two layers: a traffic ne... A new car-following model is proposed by considering information from a number of preceding vehicles with intervehicle communication. A supernetwork architecture is first described, which has two layers: a traffic network and a communication network. The two networks interact with and depend on each other. The error dynamic system around the steady state of the model is theoretically analyzed and some nonjam criteria are derived. A simple control signal is added to the model to analyze the criteria of suppressing traffic jams. The corresponding numerical simulations confirm the correctness of the theoretical analysis. Compared with previous studies concerning coupled map models, the controlled model proposed in this paper is more reasonable and also more effective in the sense that it takes into account the formation of traffic congestion. 展开更多
关键词 traffic flow coupled map car-following model inter-vehicle communication SUPERNETWORK
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Rate Control Algorithm of Wireless Video Based on Visual Saliency Map Model 被引量:1
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作者 阮若林 胡瑞敏 +1 位作者 李忠明 尹黎明 《China Communications》 SCIE CSCD 2011年第7期105-110,共6页
In order to further improve the efficiency of video compression, we introduce a perceptual characteristics of Human Visual System (HVS) to video coding, and propose a novel video coding rate control algorithm based on... In order to further improve the efficiency of video compression, we introduce a perceptual characteristics of Human Visual System (HVS) to video coding, and propose a novel video coding rate control algorithm based on human visual saliency model in H.264/AVC. Firstly, we modifie Itti's saliency model. Secondly, target bits of each frame are allocated through the correlation of saliency region between the current and previous frame, and the complexity of each MB is modified through the saliency value and its Mean Absolute Difference (MAD) value. Lastly, the algorithm was implemented in JVT JM12.2. Simulation results show that, comparing with traditional rate control algorithm, the proposed one can reduce the coding bit rate and improve the reconstructed video subjective quality, especially for visual saliency region. It is very suitable for wireless video transmission. 展开更多
关键词 human visual system saliency map model wireless video coding rate control H.264/AVC
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Modified coupled map car-following model and its delayed feedback control scheme 被引量:1
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作者 葛红霞 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第9期69-76,共8页
A modified coupled map car-following model is proposed, in which two successive vehicle headways in front of the considering vehicle is incorporated into the optimal velocity function. The steady state under certain c... A modified coupled map car-following model is proposed, in which two successive vehicle headways in front of the considering vehicle is incorporated into the optimal velocity function. The steady state under certain conditions is obtained. An error system around the steady state is studied further. Moreover, the condition for the state having no traffic jam is derived. A new control scheme is presented to suppress the traffic jam in the modified coupled map car-following model under the open boundary. A control signal including the velocity differences between the following and the considering vehicles, and between the preceding and the considering vehicles is used. The condition under which the traffic jam can be well suppressed is analysed. The results are compared with that presented by t^onishi et al. (the KKH model). The simulation results show that the temporal behaviour obtained in our model is better than that in the KKH model. The simulation results are in good agreement with the theoretical analysis. 展开更多
关键词 traffic flow coupled map carwfollowing model optimal velocity function delayed feed-back control
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Considering Backward Effect in Coupled Map Car-Following Model 被引量:1
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作者 余寒梅 程荣军 葛红霞 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第7期117-122,共6页
Based on the pioneer work of Konishi et al,a new control method is proposed to suppress the trafficcongestion in the coupled map (CM) car-following model under open boundary condition.The influence of the followingcar... Based on the pioneer work of Konishi et al,a new control method is proposed to suppress the trafficcongestion in the coupled map (CM) car-following model under open boundary condition.The influence of the followingcar to the system has been considered.Our method and that presented by Konishi et al.[Phys.Rev.E 60 (1999) 4000]are compared.Although both the methods could suppress the traffic jam,the simulation results show that the temporalbehavior obtained by ours is better than that proposed by the Konishi's et al.The simulation results are consistent withthe theoretical analysis. 展开更多
关键词 traffic flow the coupled map car-following model feedback control
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An Object-based Approach for Two-level Gully Feature Mapping Using High-resolution DEM and Imagery: A Case Study on Hilly Loess Plateau Region, China 被引量:12
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作者 LIU Kai DING Hu +4 位作者 TANG Guoan ZHU A-Xing YANG Xin JIANG Sheng CAO Jianjun 《Chinese Geographical Science》 SCIE CSCD 2017年第3期415-430,共16页
Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) a... Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) and remote sensing imagery, combined with developed object-based methods enables automatic gully feature mapping. But still few studies have specifically focused on gully feature mapping on different scales. In this study, an object-based approach to two-level gully feature mapping, including gully-affected areas and bank gullies, was developed and tested on 1-m DEM and Worldview-3 imagery of a catchment in the Chinese Loess Plateau. The methodology includes a sequence of data preparation, image segmentation, metric calculation, and random forest based classification. The results of the two-level mapping were based on a random forest model after investigating the effects of feature selection and class-imbalance problem. Results show that the segmentation strategy adopted in this paper which considers the topographic information and optimal parameter combination can improve the segmentation results. The distribution of the gully-affected area is closely related to topographic information, however, the spectral features are more dominant for bank gully mapping. The highest overall accuracy of the gully-affected area mapping was 93.06% with four topographic features. The highest overall accuracy of bank gully mapping is 78.5% when all features are adopted. The proposed approach is a creditable option for hierarchical mapping of gully feature information, which is suitable for the application in hily Loess Plateau region. 展开更多
关键词 object-based image analysis gully feature hierarchical mapping gully erosion Digital Elevation model(DEM)
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A Spatio-temporal Data Model for Road Network in Data Center Based on Incremental Updating in Vehicle Navigation System 被引量:1
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作者 WU Huisheng LIU Zhaoli +1 位作者 ZHANG Shuwen ZUO Xiuling 《Chinese Geographical Science》 SCIE CSCD 2011年第3期346-353,共8页
The technique of incremental updating,which can better guarantee the real-time situation of navigational map,is the developing orientation of navigational road network updating.The data center of vehicle navigation sy... The technique of incremental updating,which can better guarantee the real-time situation of navigational map,is the developing orientation of navigational road network updating.The data center of vehicle navigation system is in charge of storing incremental data,and the spatio-temporal data model for storing incremental data does affect the efficiency of the response of the data center to the requirements of incremental data from the vehicle terminal.According to the analysis on the shortcomings of several typical spatio-temporal data models used in the data center and based on the base map with overlay model,the reverse map with overlay model (RMOM) was put forward for the data center to make rapid response to incremental data request.RMOM supports the data center to store not only the current complete road network data,but also the overlays of incremental data from the time when each road network changed to the current moment.Moreover,the storage mechanism and index structure of the incremental data were designed,and the implementation algorithm of RMOM was developed.Taking navigational road network in Guangzhou City as an example,the simulation test was conducted to validate the efficiency of RMOM.Results show that the navigation database in the data center can response to the requirements of incremental data by only one query with RMOM,and costs less time.Compared with the base map with overlay model,the data center does not need to temporarily overlay incremental data with RMOM,so time-consuming of response is significantly reduced.RMOM greatly improves the efficiency of response and provides strong support for the real-time situation of navigational road network. 展开更多
关键词 spatio-temporal data model reverse map with overlay model road network incremental updating vehicle navigation system data center vehicle terminal
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Equality Testing for Soil Grid Unit Resolutions to Polygon Unit Scales with DNDC Modeling of Regional SOC Pools 被引量:2
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作者 YU Dongsheng PAN Yue +4 位作者 ZHANG Haidong WANG Xiyang NI Yunlong ZHANG Liming SHI Xue-zheng 《Chinese Geographical Science》 SCIE CSCD 2017年第4期552-568,共17页
Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of... Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of soil grid units at varying cell sizes was derived from soil polygon units at six map scales,namely,1:50 000(C5),1:200 000(D2),1:500 000(P5),1:1 000 000(N1),1:4 000 000(N4) and 1:14 000 000(N14),in the Taihu Region of China.Both soil unit formats were used for regional SOC pool simulation with a De Nitrification-DeC omposition(DNDC) process-based model,which spans the time period from 1982 to 2000 at the six map scales.Four indices,namely,soil type number(STN),area(AREA),average SOC density(ASOCD) and total SOC stocks(SOCS) of surface paddy soils that were simulated by the DNDC,were distinguished from all these soil polygon and grid units.Subjecting to the four index values(IV) from the parent polygon units,the variations in an index value(VIV,%) from the grid units were used to assess its dataset accuracy and redundancy,which reflects the uncertainty in the simulation of SOC pools.Optimal soil grid unit resolutions were generated and suggested for the DNDC simulation of regional SOC pools,matching their respective soil polygon unit map scales.With these optimal raster resolutions,the soil grid units datasets can have the same accuracy as their parent polygon units datasets without any redundancy,when VIV < 1% was assumed to be a criterion for all four indices.A quadratic curve regression model,namely,y = – 0.80 × 10^(–6)x^2 + 0.0228 x + 0.0211(R^2 = 0.9994,P < 0.05),and a power function model R? = 10.394?^(0.2153)(R^2 = 0.9759,P < 0.05) were revealed,which describe the relationship between the optimal soil grid unit resolution(y,km) and soil polygon unit map scale(1:10 000x),the ratio(R?,%) of the optimal soil grid size to average polygon patch size(?,km^2) and the ?,with the highest R^2 among different mathematical regressions,respectively.This knowledge may facilitate the grid partitioning of regions during the investigation and simulation of SOC pool dynamics at a certain map scale,and be referenced to other landscape polygon patches' mesh partition. 展开更多
关键词 soil organic carbon(SOC) soil grid unit resolutions soil polygon unit map scales DeNitrification-DeComposition(DNDC) model SOC pools
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MODEL SHIFT AND STRANGE ATTRACTOR ON MBIUS STRIP
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作者 陈芳跃 陈凤娟 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第7期845-852,共8页
A new model shift mapping was given in bilateral symbol space. It is topologically conjugate with the traditional shift mapping. Similar to Smale Horseshoe, a model was constructed correspondent to the model shift map... A new model shift mapping was given in bilateral symbol space. It is topologically conjugate with the traditional shift mapping. Similar to Smale Horseshoe, a model was constructed correspondent to the model shift mapping, i.e., a class of mapping on Mbius strip was given. Its attractors' structure and dynamical behaviour were described. 展开更多
关键词 model shift mapping Mbius strip CHAOS strange attractor
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