• Water for future
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• v.28 no.2
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• pp.115-124
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• 1995

A GIS is capable of extracting various hydrological factors from DEM(digital elevation model). One of important tasks for hydrological analysis is the division of watershed. It can be an essential factor among various geometric characteristics of watershed. In this study, watershed itself and other geometric factors of watershed are extracted from DEM by using GIS technique. The manual process of tasks to obtain geometric characteristics of watershed is automated by using the functions of ARC/INFO software as GIS package. Scanned data was used for this study and it is converted to DEM data. Various forms of representation of spatial data are handled in main module and GRID module of ARC/INFO. GRID module is used on a stream in order to define watershed boundary, so it would be possible to obtain the watersheds. Also, a flow direction, stream networks and orders are generated. The results show that GIS can aid watershed management and research and surveillance. Also the geometric characteristics parameters of watershed can be quantified with ease using GIS technique and the hardsome process can be automated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.105-117
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• 2004

In each industry field, many engineers have tried to develop integrated environments using information technology. The core technology in building integrated environments is the database based on standardized information. To meet the requirements, this study builds a database with detailed design information as a part of integrating digital information generated from every work of steel bridges. The data model used to build the database was developed based on the international standard, namely ISO/STEP. The data model is classified into geometric and non-geometric parts to represent the design information of steel bridges. The geometric parts are represented by a three dimensional solid model so that they may be able to reuse existing information. Also, the non-geometric parts represent information requirements that are analyzed by the development method of standard data model. To verify the data model, this study validates the syntax of the model on EXPRESS Engine and verifies the validation of the model by applying the design data of Hannam bridge to the database.

• The Mathematical Education
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• v.60 no.4
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• pp.543-554
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• 2021

The dynamic geometric environment plays a positive role in solving students' geometric problems. Students can infer invariance in change through dragging, and help solve geometric problems through the analysis method. In this study, the continuous spectrum of the dynamic geometric environment can be used to solve problems of students. The continuous spectrum can be used in the 'Understand the problem' of Polya(1957)'s problem solving stage. Visually representation using continuous spectrum allows students to immediately understand the problem. The continuous spectrum can be used in the 'Devise a plan' stage. Students can define a function and explore changes visually in function values in a continuous range through continuous spectrum. Students can guess the solution of the optimization problem based on the results of their visual exploration, guess common properties through exploration activities on solutions optimized in dynamic geometries, and establish problem solving strategies based on this hypothesis. The continuous spectrum can be used in the 'Review/Extend' stage. Students can check whether their solution is equal to the solution in question through a continuous spectrum. Through this, students can look back on their thinking process. In addition, the continuous spectrum can help students guess and justify the generalized nature of a given problem. Continuous spectrum are likely to help students problem solving, so it is necessary to apply and analysis of educational effects using continuous spectrum in students' geometric learning.

• Fibers and Polymers
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• v.7 no.4
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• pp.436-441
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• 2006

An integrated platform for garment drape simulation system has been developed. In this system, garment patterns from conventional two-dimensional CAD systems can be assembled into a three-dimensional garment on a parametrically resizable realistic human body model. A fast and robust particle-based physical calculation engine has been developed for garment shape generation. Then a series of geometric and graphical techniques were applied to create realistic impressions on simulated garments. This system can be used as the rapid prototyping tool for garments in the future quick-response system.

• Journal of the Korean Mathematical Society
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• v.52 no.6
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• pp.1271-1286
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• 2015

An operator T on a complex Hilbert space H is called skew symmetric if T can be represented as a skew symmetric matrix relative to some orthonormal basis for H. In this paper, we study skew symmetric operators with eigenvalues. First, we provide an upper-triangular operator matrix representation for skew symmetric operators with nonzero eigenvalues. On the other hand, we give a description of certain skew symmetric triangular operators, which is based on the geometric relationship between eigenvectors.

• Korean Journal of Mathematics
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• v.25 no.1
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• pp.127-135
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• 2017

The manifold $^*g-ESX_n$ is a generalized n-dimensional Riemannian manifold on which the differential geometric structure is imposed by the unified field tensor $^*g^{{\lambda}{\nu}}$ through the ES-connection which is both Einstein and semi-symmetric. The purpose of the present paper is to prove a necessary and sufficient condition for a unique Einstein's connection to exist in 5-dimensional $^*g-ESX_5$ and to display a surveyable tnesorial representation of 5-dimensional Einstein's connection in terms of the unified field tensor, employing the powerful recurrence relations in the first class.

• Journal of applied mathematics & informatics
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• v.5 no.1
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• pp.141-152
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• 1998

Based on the geometric representation an efficient al-gorithm is designed to find all articulation points of a permutation graph. The proposed algorithm takes only O(n log n) time and O(n) space where n represents the number of vertices. The proposed se-quential algorithm can easily be implemented in parallel which takes O(log n) time and O(n) processors on an EREW PRAM. These are the first known algorithms for the problem on this class of graph.

• Bulletin of the Korean Mathematical Society
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• v.43 no.4
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• pp.813-820
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• 2006

We consider a MAR model with ARCH type conditional heteroscedasticity. MAR-ARCH model can be derived as a smoothed version of the double threshold AR-ARCH model by adding a random error to the threshold parameters. Easy to check sufficient conditions for strict stationarity, ${\beta}-mixing$ property and existence of moments of the model are given via Markovian representation technique.

• Korean Journal of Mathematics
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• v.23 no.2
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• pp.313-321
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• 2015

The manifold $^*g-ESX_n$ is a generalized n-dimensional Riemannian manifold on which the differential geometric structure is imposed by the unified field tensor $^*g^{{\lambda}{\nu}}$ through the ES-connection which is both Einstein and semi-symmetric. The purpose of the present paper is to prove a necessary and sufficient condition for a unique Einstein's connection to exist in 3-dimensional $^*g-ESX_3$ and to display a surveyable tnesorial representation of 3-dimensional Einstein's connection in terms of the unified field tensor, employing the powerful recurrence relations in the first class.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1317-1320
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• 1993

We are concerned with developing a robust method for comprehensive scene analysis. In particular, we address the problem of representing spatial relations between regions in a segmented 2D image. Spatial relations are modeled as fuzzy sets. The method has two aspects, symbolic and quantitative, consisting of assigning labels for spatial relations and numeric degrees to which a relation holds respectively. The procedure of deriving a spatial relation is hierarchical taking into account geometric/physical characteristics of the regions in question.