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Search Results: 1 - 10 of 114904 matches for " LIU Ren-yi "
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A GIS-based method for flooded area calculation and damage evaluation

LIU Ren-yi,LIU Nan,

地理学报 , 2001,
Abstract: Using geographic information system to study flooded area and damage evaluation has been a hotspot in environmental disaster research for years. In this paper, a model for flooded area calculation and damage evaluation is presented. Flooding is divided into two types: ‘source flood’ and ‘non-source flood’. The source-flood area calculation is based on seed spread algorithm. The flood damage evaluation is calculated by overlaying the flooded area range with thematic maps and relating the result to other social and economic data. To raise the operational efficiency of the model, a skipping approach is used to speed seed spread algorithm and all thematic maps are converted to raster format before overlay analysis. The accuracy of flooded area calculation and damage evaluation is mainly dependent upon the resolution and precision of the digital elevation model (DEM) data, upon the accuracy of registering all raster layers, and upon the quality of economic information. This model has been successfully used in the Zhejiang Province Comprehensive Water Management Information System developed by the authors. The applications show that this model is especially useful for most counties of China and other developing countries.
A Model for Spatial Data Management Based on RDBMS and Its Implementation in Land Registration
基于RDBMS的空间数据管理模型及 在土地产权产籍系统中的实现

LIU Ren-yi,
刘仁义

中国图象图形学报 , 2000,
Abstract: The technology of management for spatial data in RDBMS is currently one of the research focus. In GIS integrated environment, the embedded database engine of spatial database and attribute database is encapsulated entirely by GIS platform and its efficiency is quite high. But it is difficult for spatial database engine (SDE) to operate mass database and manage application system of GIS with client (browser)/server structure. Although the functions of commercial enterprise RDBMS are very perfect, it do not still meet special demands of GIS, that is, it must be able to process spatial data (maps) in database. The spatial database engine (SDE) makes the RDBMS to be able to manage the spatial data and build relationships with attribute data. In this paper, a data structure model of spatial data engine (SDE) is presented. The paper analyses the system structure of the data model, the data organization and the expression of spatial graphical features. According to the given data structure model, we realize the operation of storage, topologic arithmetic and topologic analysis for spatial graphical data in RDBMS based on SQL Server. The application in land registration system shows that Spatial Database Guide (SDG) based on given data structure model runs reliably and well which cab be used widely in development of GIS.
A GIS-based method for flooded area calculation and damage evaluation
Liu Ren-yi,Liu Nan,
LIU Ren-yi
,LIU Nan

地理学报(英文版) , 2001,
Abstract: Using geographic information system to study flooded area and damage evaluation has been a hotspot in environmental disaster research for years. In this paper, a model for flooded area calculation and damage evaluation is presented. Flooding is divided into two types: 'source flood' and 'non-source flood'. The source-flood area calculation is based on seed spread algorithm. The flood damage evaluation is calculated by overlaying the flooded area range with thematic maps and relating the result to other social and economic data. To raise the operational efficiency of the model, a skipping approach is used to speed seed spread algorithm and all thematic maps are converted to raster format before overlay analysis. The accuracy of flooded area calculation and damage evaluation is mainly dependent upon the resolution and precision of the digital elevation model (DEM) data, upon the accuracy of registering all raster layers, and upon the quality of economic information. This model has been successfully used in the Zhejiang Province Comprehensive Water Management Information System developed by the authors. The applications show that this model is especially useful for most counties of China and other developing countries.
Detectable MeV neutrinos from black hole neutrino-dominated accretion flows
Tong Liu,Bing Zhang,Ren-Yi Ma,Li Xue
Physics , 2015,
Abstract: Neutrino-dominated accretion flows (NDAFs) around rotating stellar-mass black holes (BHs) have been theorized as the central engine of relativistic jets launched in massive star core collapse events or compact star mergers. In this work, we calculate the electron neutrino/anti-neutrino spectra of NDAFs by fully taking into account the general relativistic effects, and investigate the effects of viewing angle, BH spin, and mass accretion rate on the results. We show that even though a typical NDAF has a neutrino luminosity lower than that of a typical supernova, it can reach $10^{50}-10^{51}~{\rm erg~s^{-1}}$ peaking at $\sim 10$ MeV, making them potentially detectable with the upcoming sensitive MeV neutrino detectors if they are close enough to Earth. Based on the event rate of NDAFs in the local universe, we estimate a detection rate up to $\sim$ 5 per century by the Hyper-Kamiokande detector. Detecting one such event would establish the observational evidence of NDAFs in the universe.
A Study of Performance Optimization Method for Massive Spaito-temporal Data Based on Spatio-temporal Partition Clustering
基于时空分区聚簇的海量时空数据性能优化方法研究

XIE Jiong,LIU Ren-yi,LIU Nan,
谢炯
,刘仁义,刘南

中国图象图形学报 , 2006,
Abstract: Integrative management of massive spatio-temporal data and the relevant capabilities for time series analysis are important research targets of new generation GIS software architecture.At present,access efficiency of spatial and spatio-temporal data based on seamless massive table mechanism needs solid improvement.For managing massive spatio-temporal data effectively and improving spatio-temporal search performance,partitioning and clustering method of large object-relational database platform are extended to spatio-temporal dimension,and performance optimization method for massive spaito-temporal data based on spatio-temporal partition clustering is presented,which is based on extended relational spatio-temporal data model.The search efficiency test on single table of 2GB to 60GB shows that STPC provides better spaito-temporal search performance(about 10.1%) than the normal data organization methods.
Research on Integration of Multiple Type Remote Sensing Image
多源遥感影像的系统集成研究

CHEN Jian,LIU Ren-yi,LIU Nan,
陈建
,刘仁义,刘南

计算机应用研究 , 2005,
Abstract: Remote sensing data has the character of multiple type and complex organization. It is difficult to integrate different remote sensing data in common remote sensing image process platform, This paper prompt different source-Common struct as the way of settling the problem. Whereas the data has the character of vagrant, this paper offer the method of multi buffer set to realize the fast display and process of vagrant data, At last, the realization of the design and methods is presented.
A Study on TGIS Based on Dynamic Multilevel Base State with Amendments
基于动态多级基态的修正模型的TGIS研究

ZHANG Feng,LIU Ren-yi,LIU Nan,
张丰
,刘仁义,刘南

中国图象图形学报 , 2004,
Abstract: It is inefficient that realizing the query and redivivus of the history information based on the modal of base state with amendments though the modal can store change data with low redundancy. Based on the character of spatio-temporal cohesion and the spatio-property's, this paper introduces a method for designing and building spatio-temporal database based on dynamic multilevel base state with amendments, through analyzing the parcel land change character of the object-oriented TGIS. The modal of based on dynamic multilevel base state with amendments (DMBSA) is derived from the modal of base state with amendments and conquer the shortcoming of the modal. At last, a self-developed software package of land cadastral information system (ReGIS) based on above model and methods is presented. The application - ReGIS states that the modal of based on dynamic multilevel base state with amendments (DMBSA)can store and manage spatio-temporal data with low redundancy and trace history information efficiently.
The identification method of the water flooded layer based on the wavelet entropy
基于小波熵水淹层识别方法探索

WANG Ren-yi,LIU Yue-qiang,
王任一

地球物理学进展 , 2007,
Abstract: The information of petroliferous reservoir is hided in the level of differential waveform complexity between the resistivity and porosity log curves of reservoirs.The wavelet coefficient energy group of time-frequency surface has distinct difference for different swept extent.Along with water flooded extent increase,the energy group distribution gradually tends to be simple.The signal of water flooded reservoir reflects in the energy entropy of wavelet coefficient,which enlarges the information of water flooded reservoir and makes identifying the swept layer easy.The conventional log explanation theory badly identifies the low resistivity oil layer,which is well identified by the identification method of swept layer based on the wavelet entropy of log signal.
A Study on Spatio-temporal Data Model based on Feature and Event
基于双效机制的时空数据模型研究

TENG Long-mei,LIU Ren-yi,LIU Nan,
滕龙妹
,刘仁义,刘南

遥感学报 , 2005,
Abstract: The feature is an essential element that comprises spatio-temporal data information and the event is a fundamental factor that result in changing spatio-temporal data.Basing on analyzing several existing Spatio-temporal Data Model,this paper introduces a new Spatio-temporal Data Model based on feature and event double mechanisms.The character of spatio-temporal data changing is analyzed.And how to organize data,build relations between features and storage data in spatio-temporal database are also emphatically discussed.At last,a software package of dynamic land use information system based on above model and methods are introduced.Its running network environment is Windows NT Server 2000 and client is Windows workstation 4.0/2k/xp professional operation systems.Another important technology used in dynamic land use information system is a self-developed Attribute Database Engine(Dblink) combined with Spatial Database Engine(SDE).It is proven efficient in realizing the query and retrospect of the history information during system's operating.
Research of WebGIS Based on CORBA and Oracle Spatial
基于CORBA和Oracle Spatial的万维网GIS研究

YU Jian-jun,LIU Nan,LIU Ren-yi,
俞剑君
,刘南,刘仁义

计算机应用研究 , 2005,
Abstract: Maturity devel opment of CORBA technical specification, which provide a good assurance for solving distributed computer problem in the isomerous platform, developing WebGIS that is powerful,commonability high and can be operated each other. Continual renovation and growth of the spatial database engine:Oracle Spatial, make the management of magnanimity spatial data based on large-scale commercial relation database more effective. This paper discusses the feasibility of integrating the CORBA, Spatial database engine with WebGIS, also has designed and developed a common WebGIS application platform based on these.
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