• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.927-928
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• 2010

• The Pure and Applied Mathematics
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• v.17 no.4
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• pp.299-306
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• 2010

In this article we consider axes of a complete embedded minimal surface in $R^3$ of finite total curvature, and then prove that there is no planar ends at which the Gauss map have the minimum branching order if the minimal surface has a single axis.

• Journal of the Korean earth science society
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• v.36 no.3
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• pp.280-299
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• 2015

The purpose of this study was to investigate the effects of an instruction using geologic planar figures on high school students' ability of spatial visualization and geologic spatial ability and also to explore its applicability as an instructional strategy through the investigation of students' perception about the instruction using mixed methodology. For this purpose, we developed 10 planar figures of geologic structures (2 horizontal layers, 2 vertical layers, 4 angular layers, 1 fault, and 1 fold), and tested students' spatial visualization ability and geologic spatial ability before and after the implementation in class. In addition, in order to investigate students' perception on the instruction, we conducted quantitative research using questionnaires comprised of the cognitive and the affective domain, and followed by focus group interview that was conducted to obtain deeper understanding of their perception. Findings revealed that the instruction using geologic planar figures was effective to enhance spatial visualization ability and geologic spatial ability. It was also helpful for students to enhance their ability to perceive the spatial configuration of the geologic structures as well as the ability to penetrate visually into the images of the structures. The results of the students' perception on the instruction showed that the students recognized the instruction using geologic planar figures as a strongly positive teaching method both in the cognitive and affective domain. We concluded that geologic planar figures could be used as an effective tool for the lesson of 'mapping and interpreting of geological map', and be highly applicable for the advanced class in high schools.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.343-348
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• 2019

In this paper, a dual-band antenna is proposed for the autonomous vehicle as well as omni-directional. The proposed antenna operates in the 4G/LTE band (1,710~2,170MHz) and 5G/NR band (3,400~3,700MHz). In order to obtain the dual-band operation, the planar monopole antenna is proposed as the novel structure with single port of the 50ohm. To give the properties of dual-band, an additional antenna element with slit was added to the planar monopole antenna, and then a structural adjustment parameter was optimized for achieving the target performance in bands. The planar monopole antenna in the LTE band acts as the coupled feed for the added parasitic radiator in the 5G NR band. The proposed antenna has $38.5{\times}36.0{\times}1.0[mm^3]$ on a ground with diameter of 96mm. From the fabrication and measurement results, the impedance bandwidth (VSWR<2) of the proposed antenna covers 1,480~2,260MHz (LTE band: 1,710~2,170MHz) and 3,310~3,930MHz (5G NR band: 3,400~3,700MHz). The proposed planar monopole antenna also obtained the measured gain and radiation pattern of omni-directional radiation pattern in the anechoic chamber.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2464-2478
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• 2013

Image stitching techniques produce an image with a wide field-of-view by aligning multiple images with a narrow field-of-view. While conventional algorithms successfully stitch images with a small parallax, structure misalignment may occur when input images contain a large parallax. This paper presents an image stitching algorithm that aligns images with a large parallax by regional linear warping. To this end, input images are first approximated as multiple planar surfaces, and different linear warping is applied to each planar surface. For approximating input images as multiple planar surfaces, the concept of dominant edges is introduced. Dominant edges are defined as conspicuous edges of lines in input images, and extracted dominant edges identify the boundaries of each planar surface. Dominant edge extraction is conducted by detecting distinct changes of local characteristics around strong edge pixels. Experimental results show that the proposed algorithm successfully stitches images with a large parallax without structure misalignment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2113-2122
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• 1994

The 3-D FEM analysis for simulating the stamping operation of planar anisotropic sheet metals with arbitrarily-shaped tools is introduced. An implicit, incremental, updated Lagrangian formulation with a rigid-viscoplastic constitutive equation is employed. Contact and friction are considered through the mesh-normal, which compatibly describes arbitrary tool surfaces and FEM meshes without depending on the explicit spatial derivatives of tool surfaces. The consistent full set of governing relations, comprising equilibrium equation and mesh-normal geometric constraints, is appropriately linearized. The linear triangular elements are used for depicting the formed sheet, based on membrane approximation. Barlat's non-quadratic anisotropic yield criterion(strain-rate potential) is employed, whose in-plane anisotropic properties are taken into account with anisotropic coefficients and non-quadratic function parameter. The planar anisotropic finite element formulation is tested with the numerical simulations of the stamping of an automotive hood inner panel and the drawing of a hemispherical punch. The in-plane anisotropic effects on the formability of both mild steel and aluminum alloy sheet metals are examined.

• Journal of Sensor Science and Technology
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• v.13 no.5
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• pp.350-355
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• 2004

A novel UV sensor was manufactured and characterized using the evanescentfield coupling between fiber-planar waveguide (PWG) coupler and prism. A spiroxazine dye was chosen as planar waveguide because its photochromic isomerization induced by UV irradiation. A novel UV sensor was proposed to measure the variation of refractive index and absorption coefficient simultaneously. The wavelength responses of these sensors by UV exposure times were measured 0.48 nm/sec, 0.757 nm/sec, and ATR output power variations were measured $-0.424{\mu}W$/sec and $-0.62{\mu}W$/sec when UV exposure power were 3 mW and 5 mW, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.10
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• pp.1409-1416
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• 2000

In this study, turbulent flows in a planar combustor which has a square rib-type flame holder are numerically investigated by Large Eddy Simulation(LES). Firstly, the flow fields with or without jet injection downstream of the flame-holder are examined using uniform inlet velocity. Comparison of the present LES results with experimental one shows a good agreement. Secondly, to investigate mixing of oxidizer(air) and fuel injected behind the flame holder, the scalar-transport equation is introduced and solved. From the instantaneous flow and scalar fields, complex and intense mixing phenomena between fuel and jet are observed. It is shown that the ratio of jet to blocked air velocity is an important factor to determine the flow structure. Especially, when the ratio is large enough, the fuel jet penetrates the main vortices shed from the flame holder, resulting in significant changes in the flow and scalar fields.

• School Mathematics
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• v.17 no.4
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• pp.531-553
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• 2015

This study discussed a sketch map and planar figure, classical contents in math curriculum of Korea. Two problems were posed. One was the degree of difficulty and ambiguous intentions of some contents in 5th grade math textbook of 2009 revised curriculum. The other was the status of sketch maps and planar figures in more general view. We looked into elementary mathematics textbooks of former Korean national curriculums and other countries to discuss the problems. The reason why the present Korean textbook has such contents was considered, based on the result of searching former Korean and foreign textbooks. The suggestions in view of expression and building of 3D shapes were also talked.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.12
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• pp.60-66
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• 2011

There are several technological problems have to be resolved for LEDs to be used as a general purpose light source. In addition, there are several differences between existing luminaires and the general planer LED luminaire for the intensity distribution. Therefore, the optical engineer then faces the challenging a problem of designing for a spatially extended and non-uniform light source. In the previous studies on the optical design of luminaires, a lot of studies on reflectors and light source have been conducted but the ones on prisms and lenses are insufficient at present. This study developed the numerical model of planar prism LED luminaire to control luminous intensity distribution of LED luminaires. And this study presents an optical calculation process for the prism optical design of a planar prism LED luminaire and a comparison of the simulation results between the developed numerical model and Photopia 2.0 to verify the accuracy of the numerical model. In addition, this study showed a method for the control of various luminous intensity distribution from the developed numerical model.