• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.94-109
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• 2006

An improved meshfree method called the Petrov-Galerkin natural element (PG-NE) method is introduced in order to secure the numerical integration accuracy. As in the Bubnov-Galerkin natural element (BG-NE) method, we use Laplace interpolation function for the trial basis function and Delaunay triangles to define a regular integration background mesh. But, unlike the BG-NE method, the test basis function is differently chosen, based on the Petrov-Galerkin concept, such that its support coincides exactly with a regular integration region in background mesh. Illustrative numerical experiments verify that the present method successfully prevents the numerical accuracy deterioration stemming from the numerical integration error.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.254-257
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• 2007

This paper presents an examination of the spatial integration method for extracting the RCS of a trihedral corner reflector from SAR images for SAR external calibration. An exact external radiometric calibration technique is required for extracting an exact calibration constant. Therefore, we examine the accuracy of the spatial integration method, which is commonly used for the SAR external radiometric calibration. At first, an SAR image for a trihedral corner reflector is simulated with a high-resolution SAR impulse response with a known theoretical RCS of the reflector, and a background clutter image for the high resolution SAR system is also generated. Then, a SAR image in a high resolution is generated for a trihedral comer reflector located on a background clutter by superposition of the two SAR images. The radar cross section of a trihedral corner reflector in the SAR image is retrieved by integrating the radar signals of the pixels adjacent to the reflector for various size of the integration area. By comparison of the measured RCS by the integration method and the theoretical RCS of the reflector, the effect of the size of the integration area on the extraction of the calibration constant is examined.

• The Mathematical Education
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• v.37 no.1
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• pp.101-114
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• 1998

In this thesis, We tried to introduce definite integration to the curriculum of high school mathematics with numerical integration, which had been introduced with quadrature method. For this purpose, We used new experimental mathematics approaches, so-called investigation and examination. In chapter II, We examined how much computers had been used in teaching mathematics. In chapter III, We presented the theoretical background of approximation integration within numerical integration. In chapter IV, We studied and compared various methods of numerical integration, and examined the relation between curvature of a curved line and numerical integration. In order to study more easily, We used some of computer programs. We hope that this thesis will be a turning point in developing new teaching methods and improving curriculum of mathematics in high school.

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.64-76
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• 2003

In this work, a new penalty formulation is proposed for the analysis of Mindlin-Reissner plates by using the element-free Galerkin method. A penalized weak form for the Mindlin-Reissner Plates is constructed through the exterior penalty method to enforce the essential boundary conditions of rotations as well as transverse displacements. In the numerical examples, some typical problems of Mindlin-Reissner plates are analyzed, and parametric studies on the order of integration and the size of influence domain are also carried out. The effect of the types of background cells on the accuracy of numerical solutions is observed and a proper type of background cell for obtaining optimal accuracy is suggested. Further, optimal order of integration and basis order of Moving Least Squares approximation are suggested to efficiently handle the irregularly distributed nodes through the triangular type of background cells. From the numerical tests, it is identified that unlike the finite element method, the proposed element-free Galerkin method with penalty technique gives highly accurate solution without shear locking in dealing with Mindlin-Reissner plates.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1376-1383
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• 2001

Meshless methods, developed in various ways over the past decade, have been attractive as new computational methods in that they do not need mesh generation in analyzing procedure. But most of these methods were not truly meshless methods because background meshes were required for the spatial integration of a weak form. Accordingly, in this paper, nodal integration for truly meshless methods has been studied, and an improvement scheme is proposed. To improve stabilization and accuracy, which are the weak points in previous nodal integration methods, the integration area is transformed to circle and then numerically integrated. This method does not need any adding term for stabilization in the variational formulation and then simplifies the integration procedure. Numerical test results show that the proposed method is more accurate, stable, and reasonable than the existed nodal integration methods.

• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.77-91
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• 2022

North-South Korea economic integration is progressing slowly given the sensitive responses to changes in internal and external conditions. Nevertheless, advanced discussions focusing on North-South Korean economic cooperation should continue. Given this background, various studies of the economic effects of economic integration between North and South Korea have been conducted, but research on agricultural issues has been limited. The purpose of this study is to analyze the impact of the economic integration of South and North Korea on the agricultural market. In this study, a simultaneous equation model was constructed using a growth model. Solow's growth accounting approach is used to construct a model for estimating the macroeconomic effect of North-South economic integration. Also, the construction of growth accounting formulas subdivided into South and North Korea as well as agriculture and non-agricultural fields during the construction of the growth model is a major research achievement and differentiates it from previous studies. It is expected that the results of this study will serve as basic information for preparing policy measures to promote integration. However, there are many limitations when estimating the economic effects of North-South agricultural integration and obtaining policy implications given the insufficient available statistical data on agriculture in North Korea and the lack of related studies in the agricultural field. Therefore, it should be noted that there is an inherent problem in that the analysis results vary greatly depending on the assumptions set, as there is inevitably no choice but to rely on many and strong assumptions.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.1 s.5
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• pp.115-121
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• 1995

Recently, spatial integration for mineral exploration is regarded as an important task of various geological applications of GIS. Therefore, theoretical bases of data representation and reasoning concerned with Dempster-Shafer theory and Fuzzy theory were systematically as the data-driven integration methodologies for raster-based geoinformation; they are distinguished from target-driven methodology based on statistical background. According to previous actual applications of these methods to mineral exploration, they have been proven to provide useful information related to hidden target mineral deposits, and it is thought that some suggestions in this study are helpful to further real applications including representation, reasoning, and interpretation stages in order to obtain a decision-supporting layer.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.101-104
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• 1997

Providing information on corporate level decision making for multiple decision makers in a consistent way is essential in Decision Support Systems. However, since the decision makers have different background and knowledge, the models used by them are also different in representation models. This makes the decision makers require a lot of efforts for model integration in an integrated decision making. The purpose of this paper is to propose an integration mechanism for synthetic use of multi-abstraction level decision making models. The proposed integration mechanism consists of model interpretation phase, model transformation phase and model integration phase. Specifically, the model transformation phase is divided into model tightening mode which gather information to makes a model transformed into upper level model, and model relaxing mode which makes lower level model.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.53-60
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• 2001

Meshfree methods have been attracting issue as computational methods during past a few years. Nowadays, various meshfree methods such as EFGM, RKPM h-p cloud method and etc. were developed and applied in engineering problems. But, most of them were not truly meshless method because background mesh of cell was required for the spatial integration of a weak form. A nodal integration is required for truly meshless methods but it is known that this method gives a little unstable and incorrect solutions. In this paper, an improvement scheme of the existed nodal integration which the weak form can be simply integrated without any stabilization term is proposed. Numerical tests show that the proposed method is more convenient and gives more correct solutions than the previous method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.33-45
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• 1998

The typical characteristic of PDM(Product Data Management) System seperates the databases to store the meta data and applications. Therefore, meta data contains the information for the location of file, user profiles, relationships between the files, and process. PDM utilizes these information efficiently and does file management, configuration management, and process management. In this view, the integration strategy of PDM is to merge data and process. In the view of architecture, the interface between data and application and the actions of each application execute seamlessly. This architecture is viewed as integrated data and process among enterprises and implemented with client/server technology in distributed process environment that interfaced with open object-oriented technology which is developed with business object in the object-oriented infrastructure. In this paper, we studied the definition, function, and scope of PDM and researched the core technologies to implement the PDM integration environment. We also researched the PDM utilization in distributed enterprise environment and implementation of PDM integration environment with this technical background.