• Journal of Korean Association for Spatial Structures
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• v.2 no.3 s.5
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• pp.61-70
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• 2002

The objective of this study is the development of a size and shape discrete optimum design algorithms, which is based on the genetic algorithms and the fuzzy theory. This algorithms can perform both size and shape optimum designs of plane and space trusses. The developed fuzzy shape-GAs (FS-GAs) was implemented in a computer program. For the optimum design, the objective function is the weight of structures and the constraints are limits on loads and serviceability. This study solves the problem by introducing the FS-GAs operators into the genetic.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.4
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• pp.9-21
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• 2004

The current paper proposes a genetic algorithm (GA)-based segmentation method that can automatically extract and track moving objects. The proposed method mainly consists of spatial and temporal segmentation; the spatial segmentation divides each frame into regions with accurate boundaries, and the temporal segmentation divides each frame into background and foreground areas. The spatial segmentation is performed using chromosomes that evolve distributed genetic algorithms (DGAs). However, unlike standard DGAs, the chromosomes are initiated from the segmentation result of the previous frame, then only unstable chromosomes corresponding to actual moving object parts are evolved by mating operators. For the temporal segmentation, adaptive thresholding is performed based on the intensity difference between two consecutive frames. The spatial and temporal segmentation results are then combined for object extraction, and tracking is performed using the natural correspondence established by the proposed spatial segmentation method. The main advantages of the proposed method are twofold: First, proposed video segmentation method does not require any a priori information second, the proposed GA-based segmentation method enhances the search efficiency and incorporates a tracking algorithm within its own architecture. These advantages were confirmed by experiments where the proposed method was success fully applied to well-known and natural video sequences.

• Spatial Information Research
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• v.18 no.1
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• pp.77-87
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• 2010

Spatio-temporal join operators are essential to the management of spatio-temporal data such as moving objects. For example, the join operators are parts of processing to analyze movement of objects and search similar patterns of moving objects. Various studies on spatio-temporal join queries in outdoor space have been done. Recently with advance of indoor positioning techniques, location based services are required in indoor space as well as outdoor space. Nevertheless there is no one about processing of spatio-temporal join query in indoor space. In this paper, we introduce continuous spatio-temporal self-join queries in indoor space and propose a method of processing of the join queries over stream data of moving objects. The continuous spatio-temporal self-join query is to update the joined result set satisfying spatio-temporal predicates continuously. We assume that positions of moving objects are represented by symbols such as a room or corridor. This paper proposes a data structure, called Candidate Pairs Buffer, to filter and maintain massive stream data efficiently and we also investigate performance of proposed method in experimental study.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.13-24
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• 2005

This paper proposes a model for the location information grading policy. Location information grading policy is that government would give a public notice of criterion for location information quality, and location information operators should elucidate the grade of provided location information. As the quality grade of services is provided in the 'terms of use' with the detailed quality specification and quality range, the user can understand the quality of location information, and can select more suitable service for their purposes. Additionally, the qualiy grading policy can enforce the location information operators and location service providers to support more stable and reliable service quality. In this paper, we propose the model of location information grades, the typical classification of quality, and the realitic policy applying model. Recent enacted 'Location Information Law' are expected to activate korean information market. In this situation, proposed location information grading policy take a role in protecting location privacy and improving the reliability of location information services.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.50-58
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• 2003

We have developed a locally variable time-step scheme matching with discontinuous grids in the flute-difference method for the efficient simulation of seismic wave propagation. The first-order velocity-stress formulations are used to obtain the spatial derivatives using finite-difference operators on a staggered grid. A three-times coarser grid in the high-velocity region compared with the grid in the low-velocity region is used to avoid spatial oversampling. Temporal steps corresponding to the spatial sampling ratio between both regions are determined based on proper stability criteria. The wavefield in the margin of the region with smaller time-step are linearly interpolated in time using the values calculated in the region with larger one. The accuracy of the proposed scheme is tested through comparisons with analytic solutions and conventional finite-difference scheme with constant grid spacing and time step. The use of the locally variable time-step scheme with discontinuous grids results in remarkable saving of the computation time and memory requirement with dependency of the efficiency on the simulation model. This implies that ground motion for a realistic velocity structures including near-surface sediments can be modeled to high frequency (several Hz) without requiring severe computer memory

• Economic and Environmental Geology
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• v.36 no.3
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• pp.243-255
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• 2003

The mathematical models for GIS-based spatial data integration have been developed for geological applications such as mineral potential mapping or landslide susceptibility analysis. Among various models, the effectiveness of fuzzy logic based integration of multiple sets of geological data is investigated and discussed. Unlike a traditional target-driven fuzzy integration approach, we propose a data-driven approach that is derived from statistical relationships between the integration target and related spatial geological data. The proposed approach consists of four analytical steps; data representation, fuzzy combination, defuzzification and validation. For data representation, the fuzzy membership functions based on the likelihood ratio functions are proposed. To integrate them, the fuzzy inference network is designed that can combine a variety of different fuzzy operators. Defuzzification is carried out to effectively visualize the relative possibility levels from the integrated results. Finally, a validation approach based on the spatial partitioning of integration targets is proposed to quantitatively compare various fuzzy integration maps and obtain a meaningful interpretation with respect to future events. The effectiveness and some suggestions of the schemes proposed here are illustrated by describing a case study for landslide susceptibility analysis. The case study demonstrates that the proposed schemes can effectively identify areas that are susceptible to landslides and ${\gamma}$ operator shows the better prediction power than the results using max and min operators from the validation procedure.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.31-38
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• 2004

This paper is about to implement a system for ground water safety evaluation. Since ground water quality is affected from the contamination source of surface water, one can estimate the magnitude of affection and the source themselves. This paper suggests a method to evaluate the spatial relationship of ground water and its contamination sources, using“contain”and“distance”operators in GIS. The research area is the Kunsan City in Chonbuk province, and are 75th wells those are located between the 4th alluvium land types. The results of measured chemical factors and results of related evaluation of these wells are stored and represented in ZEUS 2000 GIS DBMS, and an interface for searching and studying, is implemented by using ZEUS/SQLX, ZEUS/COM, and Visual Basic 6.0 programming languages. After this research, the spatial relationship between hydro-geological geo-objects and ground water is verified and a efficient evaluation system using GIS is suggested. It is the topic of further study that tries to calibrate the suggested evaluation model by applying it to wider area.

• Journal of Korea Spatial Information System Society
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• v.2 no.1 s.3
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• pp.5-16
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• 2000

OGC(Open GIS Consortium) suggests the 'OpenGIS Simple Feature Specification for CORBA' which is the OpenGIS implementation specification for CORBA to specify standard interfaces for reuse and interoperation among distributed heterogeneous GIS resources in the CORBA distributed computing environment. An OpenGIS server that supports this implementation specification moat correctly implement all interfaces defined in the OpenGIS implementation specification to be interoperable with wrapped GISs efficiently. In this paper, we have designed and implemented an OpenGIS server based an object relational GIS, called GEUS that integrates GIS and database technologies to provide spatial data types and spatial operators from the DBMS engine level. In the CORBA distributed computing environment, clients can access geospatial data stored in GIS wrapped by the OpenGIS server through the standard interfaces defined in the OpenGIS implementation specification for CORBA. In addition, clients can use geospatial operation features provided by a back-end GIS and interoperate with other GISs.

• Spatial Information Research
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• v.5 no.1
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• pp.99-113
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• 1997

This paper demonstrates the prototype implementation of existing GIS operations using an integrated CA-GIS system where a CA simulator serve an analytical engine for GIS and compares the performance of the operations implemented here with the original ones. In addition, some new GIS operations that are not available in contemporary GIS are implemented and tested within the integrated system. It has shown that most of the local and focal operations were successfully implemented with CA-GIS and some operations written with the CA simulator showed better performance. New types of operations such as various shape filters, time-series filter, and diffusion operators were able to be implemented using the CA-GIS, which appears to be significant to enhance deficient analytical capabilities of contemporary GIS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1269-1275
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• 2003

This paper addresses several issues on data caching and consistency of cached data in order to process client's queries efficiently in client/server environments. For the purpose, first of all, materialized spatial views are adapted in a client side for data caching, which is called client views. Also, an incremental update scheme using derivation relationships is applied to keep cached data of clients consistent with the rest of server databases. Materialized views support efficient query processing in a client side, however, it is difficult to keep consistent their contents by the update of a server database. In this paper, we devise cost functions on query execution and view maintenance based the cost of spatial operators so as to process client's queries efficiently. When request the client's query, in our query processing scheme, the server determines whether or not materialize it as a view due to evaluation using the related cost functions. Since the scheme supports a hybrid approach based on both view materialization and re-execution, hence, it should improve query execution times in client/server environments.