• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.957-960
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• 1997

A complete quantitative understanding of DT has been difficult because the process represents such s broad field of research. The experimental measurement of tool force is a single area of DT which still covers a wide range of possibilities. Here are numerous parameters of the process which affect cutting forces. There are also many turnable materials of current interest. To obtain information toward a better understanding of the process, a few cutting parameters and materials were selected for detail study. It was decided that free-oxygen copper and 6061-T6 alloy aluminum would be the primary test materials. There are materials which other workers have also used because of there wide use in reflective applications. The experimental phase of the research project began by designing tests to isolate certain cutting parameters. The parameters chosen to study were those that affected the cross-sectional area of the uncut chip. The specific parameters which cause this area to vary are the depth of cut and infeed per revolution, or feedrates. Other parameter such a tool nose radius and surface roughness were investigated as they became relevant to the research.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.938-941
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• 2001

A tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. In this research, tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. In addition, tool holder system is verified by vibration test using accelerometer. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Cutting velocity has been determined to have negligible effects between 4 and 21㎧.(6) Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces. Results suggest that a sample model may not be sufficient to describe the forces produced in the diamond turning process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.49-52
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining processprohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normalto the face of the workpice can be filterd through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment cotnrol action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. Based on the empirical data of the cutting dynamics, simulation results are shown.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.57-62
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• 2009

Recently, with the increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lens are unable to satisfy the required performance. An aspheric glass lens is fabricated by the high temperature and pressure molding using a tungsten carbide molding core, so precision grinding technology for the molding core surface are required. This paper reports a development of feedrate control grinding method for aspherical molding core using parallel grinding method. A plane molding core was ground using conventional and feedrate control grinding method. The performance of the feedrate control method was evaluated by measurement of surface roughness. The result indicated that the average surface roughness was reduced to 1.5 nm, which is more efficient than the conventional grinding method.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.2
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• pp.84-92
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• 2010

색채선별기는 양질의 곡물 유통을 위해 불량곡물, 이물질을 선별하는 시스템이다. 기존의 색채 선별기는 PC기반 제어시스템으로서 비교적 고가이고 부피가 크며 현장 환경에서 기계적 충격이나 먼지등에 취약하다는 문제점을 가지고 있다. 본 논문에서는 이러한 문제점을 개선하기 위해 운영체제가 탑재된 임베디드 제어기 기반의 색채선별기를 제안한다. 색채선별기는 기본적으로 곡물의 유입량 및 속도를 조절해 주는 피터부, 곡물의 영상을 받아 이미지를 처리해 주는 카메라부, 카메라부에서 받은 정보를 이용해 양품과 불량품을 분리해 주는 이젝터부로 구성된다. 본 논문에서는 개발된 지능형 색채선별기용 ARM 프로세서 기반 임베디드 제어기의 하드웨어 구성, 피더부, 카메라부, 이젝터부 간의 통신프로토콜을 이용한 총괄관리 제어와 그래픽 사용자 인터페이스(GUI)를 소개한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.191-194
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• 2003

Through using aspheric lens can result in advantages such as an improved optical transfer function, a reduced distortion path or the realization of special image field curvatures. Using the diamond turning method for generating aspherics, the company claim to be able to generate surfaces with a form error of less than $0.33\;{\mu}\;m$ and a surface roughness of less than $0.025\;{\mu}\;m$. In this paper, we are manufacturing thermal image aspheric lens. Thermal image system is electro-optical imaging device which can make visible the difference of infrared energy naturally emitted by objected. In the result of aspherical surface, the form accuracy of about $0.24\;{\mu}\;m$ P-V was obtained and the surface roughness Ra $0.004\;{\mu}\;m$. Also, a brief review of Ultra-precision system Korea photonics technology institute(KOPTI) is present in this paper.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.371-375
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• 1998

Tobacco (Nicotiana tabacum) cultivars including NC 82 and KF 114, and Datura stramonium, Physalis floridana, Gomphrena globosa, and Chenopodium spp. were added to the previous host plants tested for the further examination on the biological characteristics of tobacco mosaic virus (TMV) strains isolated from tobacco (TMV-Common), tomato (TMV-Tomato), and pepper (TMV-Pepper), In TMV-Tomato and TMV-Pepper, different symptoms were noted in P. floridana (no symptom development), and NC 82 (local lesion production on the inoculated leaves) from TMV-Common with which systemic mosaic symptoms were developed. Local lesions were developed in KF 114, D. stramonium, G. globosa, and Chenopodium spp by TMV-Common and TVM-Tomato, while no symptom was observed in KF114 and G. globosa. Also the number and size of local lesions were smaller in KF 114 than Xanthi-nc tobacco (local lesion host) infected with TMV-Tomato. Systemic necrosis was induced in Xanthi-nc and KF 114 when infected with TMV-C at high temperature, but not with the other strains.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.2
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• pp.115-122
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• 2001

The effect of mineral oil treatment in Burley 21 tobacco field on the control of potato virus Y(PVY-VN) mostly transmitted by green peach apid(Myzus persicae Sulzer) in nature was studied and the virus infection in some plants including potato, pepper, bramble, radish, etc near the tobacco fields as a virus infection source was tested by capillary tube precipitatioin test with PVY-antibody and bioassay in Xanthi-nc tobacco. The main source of PVY-VN infection in tobacco field in korea was potato(ca. 40% of test plants infected). Pepper and bramble were also infected by PVY-VN. The control level of PVY-VN infection by treatment of 0.75% liquid mineral oil with 3 % nonionic emulsifier to the plants was 84.8 % in case of the artificial transfection with a infected apterous aphid in laboratory. However, the reduction of PVY-VN disease severity in tobacco fields treated with mineral oil at late June was only 35.5%. These results suggest that mineral oil treatment is not so effective for the protection of aphid-born virus(PVY - VN) infection in tobacco fields.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.6_1
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• pp.503-509
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• 2012

The cities keep growing due to industrialization and the risk of disaster gets higher as the society gets sophisticated. The center of current disaster plan has spent more efforts on post processing of disaster and it is the current status that the plan for shelter that minimizes the life and property damage has not been established effectively. Especially, the whole area of Noksan Industrial Complex at Noksan-dong, Gangseo-gu, Busan Metropolitan City was designated as danger area of tsunami, but the shelter has not been selected. Thus, this paper is willing to select the shelter using AHP analysis and GIS method that is multi criteria decision making analysis after grasping the buildings that can be selected as the shelter.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.99-104
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• 2004

Recently, the old surveying method for acquiring surveying-geo information results had a low economic efficiency and a low dependence of precision because it took much times and high costs. So, we acquired law data by execution of control surveying through Static positioning of DGPS(Ashtech). It is computed plainmetric(X, Y) positioning through postprocessing by Prism S/W. And we computed height(Z) through control surveying by ring-closed leveling surveying. After control surveying execution, we built DEM(Digital Elevation Model) using LDT S/W and accuracy 3D detail surveying by EDM(Electronic Distance Measurement) surveying. The purpose of this study was to yield automated digital mapping and the automated amount of materials using ahead data. The conclusions were as follows; First, we built the automated amount of materials system and got high efficiency about personnel, times and precision. Second, when, people precisely positioned on railroads of a high-speed railroad and used GPS surveying, the result was permitted. Finally, it was possible to draw automated profile and cross-section using the 3D terrain model build with the DEM technique.