• The Journal of Korean Institute of Communications and Information Sciences
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• 제14권5호
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• pp.542-548
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• 1989

Rectangular microstrip antenna array using Chebyscheff polynomial is designed. The required relative currents in the rectangular microstrip array antenna are 1:2:2:1. The input admittance and returen loss of array antenna are calculated from transmission line model circuit include feed line. The calculated resonant frequency valused are in good agreement with measured values. Also, the sharp beam scanning characteristic of perfect electronic method is presented.

• Journal of the Korean Association of Geographic Information Studies
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• 제6권3호
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• pp.33-42
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• 2003

As airborne laser scanning technique is developed with high vertical accuracy recently, there come many studies on DEM(digital elevation model creation, building extraction, flood risk mapping and 3D virtual city modeling. This study applied point comparative method, contour comparative method and digital map with scale 1/5,000 to calculate RMSE of DEM in according to resolution that was constructed using rawdata being acquired by airborne laser scanning. As a result, point comparative method showed lower DEM standard error than contour comparative method, it is a reason that contour comparative method was not carried out detailed grid calculation for point comparative method. Also, digital map with scale 1/5,000 showed higher DEM standard error than point comparative method and contour comparative method in below 25.4m that is average horizontal distance among contour line, and showed similar result with contour comparative method in over 25.4m.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제64권3호
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• pp.458-464
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• 2015

This paper proposes a portable 3-D scanning technique using a laser pointer. 3-D scanning is a process that acquires surface information from an 3-D object. There have been many studies on 3-D scanning. The methods of 3-D scanning are summarized into some methods based on multiple cameras, line lasers, and light pattern recognition. However, those methods has major disadvantages of their high cost and big size for portable appliances such as smartphones and digital cameras. In this paper, a 3-D scanning system using a low-cost and small-sized laser pointer are introduced to solve the problems. To do so, we propose a 3-D localization technique for a laser point. The proposed method consists of two main parts; one is a fast recognition of input images to obtain 2-D information of a point laser and the other is calibration based on the least-squares technique to calculate the 3-D information overall. To verified our method, we carry out experiments. It is proved that the proposed method provides 3-D surface information although the system is constructed by extremely low-cost parts such a chip laser pointer, compared to existing methods. Also, the method can be implemented in small-size; thus, it is enough to use in mobile devices such as smartphones.

• Proceedings of the KWS Conference
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.91-93
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• 2005

Forming sheet metal by laser-induced thermal stresses (laser forming) has been extensively studied, and the research has focused on two-dimensional geometries using a multi-pass straight line scan. Recently there came out some useful studies or three-dimensional laser forming which is applied to doubly curved shapes. The task of 3D laser forming sheet metal is to determine a set of process parameters such as laser scanning paths, laser power and scanning speed that will make a given shape. New method for laser forming of a doubly curved surface by using geometrical information was proposed and verified by experiments. This method shows good performance in the sense of calculation time and accuracy compared to the inherent strain method.

• Journal of the Korea Institute of Military Science and Technology
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• 제12권3호
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• pp.360-367
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• 2009

In this paper, the RADANT phase scanning scheme and the transmission-type loaded line phase shifter scheme, which are applicable to the phased array systems, are studied. Using these two schemes, a theoretical method to design an electronic beam steering RADANT lens is introduced. The validity of the presented theoretical method is verified through the simplified circuit simulation results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.25-28
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• 2001

The objectives of this paper are to demonstrate the electrical degradation phenomena with Si atom's behaviors in the grainboundary of semiconducting ZnO ceramics. The ZnO ceramic devices used in this investigation were fabricated by standard ceramic techniques. Especially, $SiO_2$ were added to analyze the degradation characteristics with Si and sintered in oxygen ambient at $1300^{\circ}C$. The conditions of DC degradation test were $115{\pm}2^{\circ}C$ for 13h. Using XRD and SEM, the phase and microstructure of samples were analyzed respectively. E-J analysis was used to determine $\alpha$. Frequency analysis was accomplished to understand $R_g$ and $R_b$ at the equivalent circuit. Electrical stability improved as the amount of $SiO_2$ addition increased. This results were explain by the quantitative analysis and the line scanning method of EPMA.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제34권5호
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• pp.371-381
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• 2021

A machine vision inspection system consists of a camera, optics, illumination, and image acquisition system. Especially a scanning system has to be made to measure a large inspection area. Therefore, a machine vision line scan camera needs a line scan light source. A line scan light source should have a high light intensity and a uniform intensity distribution. In this paper, an offset calibration and slope calibration methods are introduced to obtain a uniform light intensity profile. Offset calibration method is to remove the deviation of light intensity among channels through adding intensity difference. Slope calibration is to remove variation of light intensity slope according to the control step among channels through multiplying slope difference. We can obtain an improved light intensity profile through applying offset and slope calibration simultaneously. The proposed method can help to obtain clearer image with a high precision in a machine vision inspection system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.277-279
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• 2003

The black and white image scanning system realization and design using illumination control on CIS(Contact Image Sensor) be amenable to recognize a papers, OMR and OCR sheet is proposed. The design technique is used CIS scanning sensor in fixing step motor and is optimized with DSP processor for image processing, and transfer input image data pare line in feeding a step unit to PC on the USB interface. The method of illumination control is that turn on and off of CIS lamp while scanning paper. The scanner system with optimal illumination enhanced PSNR 0.3% in scanning image.

• Laser Solutions
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• 제3권2호
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• pp.25-33
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• 2000

One of perspective direction of microfabrication is direct laser writing technology that allows to create metal, semiconductive and dielectric micropatterns on substrate surface. In this work, a two step method, the combination of seed forming process, in which metallic Al seed was selectively generated on AlN ceramic substrate by direct writing technique using a pulsed Nd : YAG laser and subsequent electroless Ni plating on the activated Al seed, was presented. The effects of laser parameters such as pulse energy, scanning speed and pulse frequency on shape of Alseed and conductor line after electroless Ni plating were investigated. The nature of the laser activated surface is analyzed from XPS data. The line width of this metallic Al and Ni is analyzed using SEM. As a results, Al seed line with 24㎛ width and 100㎛ isolated line space is obtained. Finally, laser direct writing can be applied in the field between thin and thick film technique in electronic industry.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.455-455
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• 2013

$CeO_2$ nanorings were synthesized by using a surfactant free hydrothermal method. The surface morphology, structural and optical properties of the synthesized $CeO_2$ was investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV) spectroscopy measurements. SEM images showed that the surface morphology of the formed $CeO_2$ appeared as nanorings. The XRD pattern of $CeO_2$ nanorings showed the presence of the polycrystalline $CeO_2$ phase readily indexed to the cubic fluorite structure of the $CeO_2$. The mean crystallite size of the $CeO_2$ was calculated using the Scherrer equation from the XRD line broadening of the (111) planes of the cubic $CeO_2$. The UV-Visible spectroscopy spectrum of the $CeO_2$ nanorings exhibited a strong UV absorption band around 350 nm.