• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.11-22
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• 2004

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. Consequently, reducing cache misses emerges as the most important issue in current main memory databases, in which CPU speeds have been increasing at 60% per year, compared to the memory speeds at 10% per you. In this paper, we design and implement a main-memory database system for real-time mobile GIS. Our system is composed of 5 modules： the interface manager provides the interface for PDA users； the memory data manager controls spatial and non-spatial data in main-memory using virtual memory techniques； the query manager processes spatial and non-spatial query : the index manager manages the MR-tree index for spatial data and the T-tree index for non-spatial index : the GIS server interface provides the interface with disk-based GIS. The MR-tree proposed propagates node splits upward only if one of the internal nodes on the insertion path has empty space. Thus, the internal nodes of the MR-tree are almost 100% full. Our experimental study shows that the two-dimensional MR-tree performs search up to 2.4 times faster than the ordinary R-tree. To use virtual memory techniques, the memory data manager uses page tables for spatial data, non- spatial data, T-tree and MR-tree. And, it uses indirect addressing techniques for fast reloading from disk.

• Journal of Korean Society for Geospatial Information Science
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• v.7 no.2 s.14
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• pp.81-91
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• 1999

The study on the updating of the database of Geo-Spatial Information System that is necessary condition to GSIS operation have executed actively. In this study, digital orthophotos were produced by using the product of digital photogrammetry process and then multiscale digital orthophoto maps were generated tv the concept of image pyramids. The produced digital orthophoto has 2.092 meters accuracy compared to 1:5,000 topographic map. This digital orthophoto can be implemented in various Geo-Spatial Information System, providing valuable spatial reference for other objects in the database.

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.93-106
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• 2006

A Grid Database is a database management system to process effectively and use the distributed data in a grid computing environment. Spatial data is more important than other general data according to the local characteristics and requires a large storage. The grid database can be used as the optimal system for the management of the spatial data. However, contrary to the conventional distributed database systems, the Grid Database which guarantees the local autonomy has a possibility not to provide an effective system, or it is impossible to use a centralized management environment. In order to allow flexible responses to a dynamically changing environment, it is required to use effectively reorganized method. In this paper, hierarchical reorganization method is presented for dynamic reorganization in a grid database. When the reorganization is conducted, an organizer is created to collect the information of databases. In addition, the organizer which is constructed by the hierarchical structure supports information communication and reorganization, and then it allows the support of regional reorganization operation and effective balance control. The performance assessment of the proposed method shows that the processing capacity is increased after the reorganization.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.2
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• pp.95-107
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• 2014

In general, topographical phenomena are represented graphically by data in the spatial domain, while attributes of the non-spatial domain are expressed by alpha-numeric texts. GIS functions for analysis of attributes in the non-spatial domain remain quite simple, such as search methods and simple statistical analysis. Recently, graph modeling and network analysis of social phenomena are commonly used for understanding various social events and phenomena. In this study, we applied the network analysis functions to the non-spatial domain data of GIS to enhance the overall spatial analysis. For this purpose, a novel design was presented to integrate the spatial database and the graph database, and this design was then implemented into a WebGIS system for better decision makings. The developed WebGIS with underlying synchronized databases, was tested in a simulated application about the selection of water supply households during an epidemic of the foot-and-mouse disease. The results of this test indicate that the developed WebGIS can contribute to improved decisions by taking into account the social proximity factors as well as geospatial factors.

• Spatial Information Research
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• v.9 no.1
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• pp.107-124
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• 2001

The purpose of this research is to develop system and to establish methodology for managing spatial Database in Land Management Information System(LMIS). Spatial Database which is used by a various public department such as parcel survey and registry, land use planning and Land value appraisal in local government, is composed of parcel map, topographic map and zoning map. Spatial data has been constructed and managed by various department and then hard to maintain accuracy and coinsistency. So, it is important to establish the basic data management concept that source data(ex : parcel map, topographic map, zoning map, etc.) should be managed by responsible department. at the same time, application data for bussiness (ex : individual parcel price map) must be recomposed from base map by it's own objects. This is, Spatial data management system (SDMS) should be designed, developed according to this concept for managing consistency among data, reducing construction and management cost of database. Our SDMS was developed based on Open LMIS middleware architecture using OpenGIS CORBA specification for standard interface, RUP(Rational Unified Process) for development methodology, UML(Unified Modeling Language) for system design and VisiBroker, C++, CAD system for system implementation.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1167-1167
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• 1999

Although spatial databases support an efficient spatial management on objects in the real world, they have a characteristic that process only spatial information valid at current time, So in case of change in the spatial domain, it is very hard to support an efficient historical management for time-varying spatial information because they delete an old value and then replace with new value that is valid at current time. To solve these problems, there are rapidly increasing of interest for spatiotemporal databases, which serve historical functions for spatial information as well as spatial management functions for an object. However most of them presented in an abstract time-varying spatial phenomenon, but have not presented a concrete policy in spatiotemporal databases. In this paper, we propose a spatiotemporal data model that supports bitemporal time concepts in three dimensional architecture. In the proposed model, not only data types and their operation for object of spatiotemporal databases have been classified, but also mathematical expressions using formal semantics for them have been given. Then, the data structures and their operations based on relational database model as well as object-oriented database model are presented.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.138-140
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• 2003

The aim of this study is to evaluate the effect of spatial resolutions on the accuracy to landslide susceptibility mapping. For this, landslide locations were identified in the Boun, Korea from interpretation of aerial photographs and field surveys. The topographic, soil, forest, geologic, linearment and land use data were collected, processed and constructed into a spatial database using GIS and remote sensing data. The 15 factors that influence landslide occurrence were extracted and calculated from the spatial database with 5m, 10m, 30m, 100m and 200m spatial resolutions. Landslide hazardous area were analysed and mapped using the landslide-occurrence factors by probability model, likelihood ratio, for the five cases spatial resolutions. The results of the analysis were verified using the landslide location data. In the cases of spatial resolution 5m, 10m and 30m, the verification results was similar, but in the cases of 100m and 200m the results worse than the others. Because the scale of input data was 1:5,000 ? 1:50,000, so the cases of 5m, 10m and 30m have similar accuracy but the cases of 100m and 200m have the lower accuracy. From this, there is an effect of spatial resolutions on accuracy and landslide susceptibility mapping the result is dependent on input map.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.175-181
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• 2006

AMobile-supported spatial database systems have been introduced with development of mobile computing technology, they offer an advantage that we can access the data wherever we are. However, the studies on database system in traditional distributed environments must be reconsidered again, because of characteristics of mobile database system such as mobility and instability of wireless network. A new transaction model should be required for considering the characteristics, since especially a mobile computing environment is location-dependent, compared with the location transparency in a distributed computing environment. In other aspect, normally mobile host may be moving not in all space, but in some limited path. That is, a host is moving along the roads or the geographical features adjacent to the roads. The transaction processing should be considered not on the spatial coordinate but on the geographical features. In this paper, the feature based transaction processing model is proposed to process location-dependent transaction efficiently.

• The Transactions of the Korea Information Processing Society
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• v.1 no.3
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• pp.279-289
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• 1994

A Geographic Database System is a database system which supports map-formed output and allows users to store, retrieve, manage and analyze spatial and aspatial data. Because of large data amount, takes too much time to input spatial data into a Geographic Database System and too much storage. Therefore, an efficient spatial data collecting system is highly required for a Geographic Database System to reduce the input processing time and to use the storage efficiently. In this paper, we analyze conventional vectorizing methods and suggest a different approach. Our approach vectorizes specific geographic data when the users input its aspatial data, instead of vectorizing all the map data. And also, we propose optimized vector data format using tag bit to use the storage that collected data efficiently.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.753-758
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• 2005

This study attempts at building an integrated GIS computing framework for evaluating space-time accessibility of an individual with the approach of time geography model. The proposed method is based on the integration of mobile GIS and object-relational spatio-temporal database. Three components are central to our system: ( i ) mobile GIS application that transmits spatio-temporal trajectory data of an individual; ( ii ) spatio-temporal database server that incorporates the time geography model; and (iii) geovisualization client that provides time geographic queries to the spatio-temporal database. As for the mobile GIS application, spatio-temporal trajectory data collected by GPS-PDA client is automatically transmitted to the database server through mobile data management middleware. The spatio-temporal database server implemented by extending a generic DBMS provides spatio-temporal objects, functions and query languages. The geovisualization client illustrates 3D visual results of the queries about space-time path. space-time prism and space-time accessibility. This study shows a method of integrating mobile GIS and DBMS for time geography application, and presents an appropriate spatio-temporal data model for evaluating space-time accessibility of an individual.