• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.113-122
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• 2007

The rapid growth of aerial survey and remote sensing technology has enabled the rapid acquisition of very large amounts of geographic data, which should be analyzed using real-time visualization technology. The level of detail(LOD) algorithm is one of the most important elements for realizing real-time visualization. We chose the triangulated irregular network (TIN) method to generate normalized digital elevation model(DEM) data. First, we generated TIN data using contour lines obtained from a two-dimensional(2D) digital map and created a 2D grid array fitting the size of the area. Then, we generated normalized DEM data by calculating the intersection points between the TIN data and the points on the 2D grid array. We used constrained Delaunay triangulation(CDT) and ray-triangle intersection algorithms to calculate the intersection points between the TIN data and the points on the 2D grid array in each step. In addition, we simulated a three-dimensional(3D) terrain model based on normalized DEM data with real-time visualization using a Microsoft Visual C++ 6.0 program in the DirectX API library and a quad-tree LOD algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.151-156
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• 2000

Delaunay triangulation is well balanced in the sense that the triangles tend toward equiangularity. And so, Delaunay triangulation hasn't some slivers triangle. It's commonly used in various field of CAD applications, such as shape reconstruction, solid modeling and volume rendering. In this paper, an improved Delaunay triangulation is proposed in 2-dimensions. The suggested algorithm subdivides a uniform grids into sub-quad grids, and so efficient where points are non-uniform distribution. To get the mate from quad-subdivision algorithm, the area where triangulation-patch will be most likely created should be searched first.

• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.973-986
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• 2015

Ethylene tetrafluoroethylene (ETFE) foil is a novel structural material which has being used in shell and spatial structures. This paper studies biaxial creep property of ETFE foil by creep tests and numerical simulation. Biaxial creep tests of cruciform specimens were performed using three stress ratios, 1:1, 2:1 and 1:2, which showed that creep coefficients in biaxial tension were much smaller than those in uniaxial one. Then, a reduction factor was introduced to take account of this biaxial effect, and relation between the reduction factor and stress ratio was established. Circular bubble creep test and triangle cushion creep test of ETFE foil were performed to verify the relation. Interpolation was adopted to consider creep stress and reduction factor was involved to take account of biaxial effect in numerical simulation. Simulation results of the bubble creep test embraced a good agreement with those measuring ones. In triangle cushion creep test, creep displacements from numerical simulation showed a good agreement with those from creep test at the center and lower foil measuring points.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.772-784
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• 2024

The hexagonal nodal code RENUS has been enhanced to handle irregularly deformed hexagonal assemblies. The underlying RENUS methods involving triangle-based polynomial expansion nodal (T-PEN) and corner point balance (CPB) were extended in a way to use line and surface integrals of polynomials in a deformed hexagonal geometry. The nodal calculation is accelerated by the coarse mesh finite difference (CMFD) formulation extended to unstructured geometry. The accuracy of the unstructured nodal solution was evaluated for a group of 2D SFR core problems in which the assembly corner points are arbitrarily displaced. The RENUS results for the change in nuclear characteristics resulting from fuel deformation were compared with those of the reference McCARD Monte Carlo code. It turned out that the two solutions agree within 18 pcm in reactivity change and 0.46% in assembly power distribution change. These results demonstrate that the proposed unstructured nodal method can accurately model heterogeneous thermal expansion in hexagonal fueled cores.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.2 no.1
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• pp.54-64
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• 1984

This paper is a study on structural measurement by using a terrestrial camera. The aim of this paper is to understand the method of a composition by analyzing the geometrical compositive ratio of threestoried pagodas at Gamun-Sa, Gosun-Sa, Bulguk-Sa, Seated iron Buddha in Kwang-Jn, and Main-Seat Buddha at Sukkuram Cave-temple. Measured data and contour maps are accurately obtained by means of photogrammetry, and the following points are able to he found by analyzing them. At first, for Stone Pagodas. the breaths of the Okgesuks are made to the ratio, 8 : 7 : 6. And when an equililateral triangle and an 45$^{\circ}$ isosceles triangle are drawn of which the bases are the length of the upper Gabsuk, and then a circle is drawn whose radius is the length between the vertexes of the two triangles and its center is the vertex of the former the circle passes the upper line of the third Oksin. Also it can be found that an $70^{\circ}$ isosceles triangle being drawn at base line, the triangle passes the edge point of the upper Gabsuk and the center of the third Okgesuk. Also for Budha statues, it can be found that circles whose center is that of eyes can be drawn, and if 2 lines which pass the shoulder and the center of Buddha's body are extended, they intersect the knees.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.51-55
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• 2004

In this study, the levelling and the GPS levelling were carried out with 6 points in 2km${\times}$2km area and the results were analysed. As a result of this research, we had to observe more than 15 minutes to get the height accuracy of 10mm by single frequency GPS receiver in relative surveying. We could not get more better accuracy than 10mm. we could get the height accuracy of within 10mm from observing only more than 5 minutes by double frequency GPS receiver, and of within about 3mm from observing more than 10 minutes. When the number of fixed points is within 3, the level net adjustment result is very close to the one of direct levelling survey. When the number of fixed points is 3, the less the area of triangle the better the adjustment result, and the case of including measure point has more better accuracy than that of non-including measure point.

• Journal of Biomedical Engineering Research
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• v.29 no.2
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• pp.146-150
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• 2008

In order to study cortical properties in human, it is necessary to obtain an accurate and explicit representation of the cortical surface in individual subjects. Among many approaches, surface-based method that reconstructs a 3-D model from contour lines on cross-section images is widely used. The conventional method detects match points of contours using the minimum straight distance between any pair of contour points which lie on different contours. Then, it generates a triangle strip. In general, however, it might yield small mismatches between contours in case of brain due to complex anatomical structures. In this paper, therefore, we present an improved method for tilting operation that uses the curvature values calculated from surface information. The usefulness of the proposed method has been verified using brain image.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.293-294
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• 2015

This work considers the elliptic restricted three-body problem under effects of radiation of the bigger primary, and an oblate spheroid for the smaller primary to mimic an exoplanetary system with a gas giant planet. Under the influences of both effects we look for the existence of the triangular equilibrium points and the influences of the radiation and oblateness on the locations and motion of the points. We set the system in a normalized rotating coordinate system and derive equations of motion for the third infinitesimal object. Our study shows that the effects modify the equilateral/isosceles triangle shape with respect to the primaries. The triangular points also have non-planar motion with period depending on the value of the planet oblateness.

• Korean journal of communication and information
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• v.59
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• pp.31-49
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• 2012

This study investigates normative role model of the journalists under the changing environment. Firstly, this article explores what pressure the new media environment gives to the journalists in their routine of news production and distribution. These are stated from the angle of epistemological, professional and interactive pressure. Next, as a reference for the standard journalism in the age of mass media, the idea of Rhee Young-hee, a late journalist who won respects from many Korean journalists, is studied. His firm belief in the pursuit of hard facts, rigorous investigative writing and expertism are spelt out. Then, this study explores how, in real term, this pressure changes the journalistic value, norm and practices in the newsroom. Ten of Koran journalists are interviewed in order to get their idea about the emerging journalistic standards under the digital environment. From this in-depth interviews, it is conclued that the pursuit of hard fact, investigative writing, expertism of Rhee Young-hee are, nonetheless the change of the media technology, still effective and provide good reference points for the enhancement of the standard of journalism in Korea. However, it is also suggested that the methods to fulfil desirable journalism in the digital age should be different from that of the mass communication age. The interviewees make propose that the journalist, as a network node, news curator or coordinator, should actively interact with the audiences facilitating their enhanced potential as a news 'prosumer'(producer and consumer).

• Communications of the Korean Mathematical Society
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• v.27 no.3
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• pp.513-522
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• 2012

In this paper, we prove common fixed point theorems for families of occasionally weakly compatible mappings in Menger spaces using implicit relation. Our results extend and generalize the results of Altun and Turkoglu [9] in the sense that the concept of occasionally weakly compatible maps is the most general among all the commutativity concepts. Also the completeness of the whole space, continuity of the involved maps and containment of ranges amongst involved maps are completely relaxed.