• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.297-302
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• 1997

A hemiconfocal resonator equipped with an intra-cavity adjustable aperture and a beam splitter has been studied experimentally to achieve a controlled low beam divergence operation in a vapor laser system. The dependences of output characteristics both on the aperture diameter and on the angle of beam splitter have been investigated. By adjusting the aperture diameter from 14mm to 2mm to 2mm, we were able to reduce the beam divergence from 3.1 mrad to 0.25 mrad and achieved the 8-times increase in the far-field power density.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.193-198
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• 2002

Growth and tuber development of ‘Black Magic’calla lily as affected by the rain shelter with 50％ shading and the tuber size were investigated. Tubers of five grades in size were cultivated in the rain shelter or in the open field (control). Days to emergence of shoots in the rain shelter was accelerated by 4.2 days as compared to the open field. Emergence ratio was higher as the tuber was larger, tubers grown in the rain shelter showed the significance in the growth characteristics as compared to the control. There were no significant differences in the number of flowers per tuber between the rain shelter and the open field. Flower quality was 12.2 cm longer than that in the open field. flowering characteristics was improved with the increasing tuber size. Low infection of soft rot disease of 3∼22％ was found in the rain shelter as compared to the that of 19∼83％ in the open field. Thus tubers produced under the rain shelter showed improved quality, Even if the small tubers with diameters of 0.5∼1.0 cm were cultivated in the rain shelter, the weight and diameters of tuber harvested after approximately 7 months were 50.2 g and 5.7 cm, respectively.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.403-414
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• 2004

In the accompanying paper, we proposed a real. time volumetric imaging method using a cross array based on receive dynamic focusing and synthetic aperture focusing along lateral and elevational directions, respetively. But synthetic aperture methods using spherical waves are subject to beam spreading with increasing depth due to the wave diffraction phenomenon. Moreover, since the proposed method uses only one element for each transmission, it has a limited transmit power. To overcome these limitations, we propose a new real. time volumetric imaging method using cross arrays based on synthetic aperture technique with linear wave fronts. In the proposed method, linear wave fronts having different angles on the horizontal plane is transmitted successively from all transmit array elements. On receive, by employing the conventional dynamic focusing and synthetic aperture methods along lateral and elevational directions, respectively, ultrasound waves can be focused effectively at all imaging points. Mathematical analysis and computer simulation results show that the proposed method can provide uniform elevational resolution over a large depth of field. Especially, since the new method can construct a volume image with a limited number of transmit receive events using a full transmit aperture, it is suitable for real-time 3D imaging with high transmit power and volume rate.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.80-80
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• 2004

해상도가 높아질수록 위성 탑재 카메라의 광학적 설계 조건은 까다롭다. 특히 1m급의 고해상도 영상을 얻기 위해서는 개념설계 단계에서부터 여러 가지 기술적인 면과 운용적인 면을 동시에 고려해야 하며 이러한 조건들이 상호 연관성을 가지면서 광학계의 형태나 성능을 결정하므로 다양한 해석과 분석이 필요하다. 해상도, 촬영고도, 관측폭 그리고 촬영소자의 크기에 의해 광학계의 초점거리가 결정되며 광학계의 유효구경을 추가하면 신호량 성능에 대한 예측이 가능하다. (중략)

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.183-184
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• 2010

In this study, it suggested evaluation method of carbonation about crack to occur in an early age. And it compared penetration depth of carbonation with crack size.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.11a
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• pp.50-51
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• 2013

국내에서 스프링클러 설계 시 주로 적용하는 배관스케줄방식은 용도분류에 의해 결정되는 스케줄로, 배관의 구경이 선택되고 배관의 크기에 따라 설치될 수 있는 스프링클러헤드의 개수가 주어져 있는 스프링클러설비이다. 이는 NFPA13의 배관스케줄방식을 준용한 것이나 적용의 오류로 인하여 잘못된 설계를 수행하고 있다. 이를 시정하기 위하여 국내 기술기준과 NFPA13기준을 확인하고 문제점의 지적 및 바른 배관스케줄방식의 적용을 제시하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.598-600
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• 2003

기존의 재활용기계는 광센서. 근접센서, 자장센서를 이용하여 캔의 부분적인 정보들을 수집하고 캔의 종류를 구별하였다[l]. 이는 시스템 제작비용이 저렴하고 수행속도가 빠르다는 장점이 있지만 오인식 확률이 크기 때문에 제품화 하였을 때 위험부담이 크다는 한계를 지닌다. 따라서, 이와 같은 문제점을 해결하기 위해 본 논문에서는 기계 내부에 카메라를 설치하여 획득된 캔 영상의 특징을 분석하고, 파쇄 가능한 일반 캔과 파쇄해서는 안될 부탄가스 캔을 선별하기 위한 영상처리 기법을 제안한다.

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.64-69
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• 2003

Using a high fewer electron beam gun (max. power 20 kW), Gadolinium (Gd, atomic number 64) metal was melted and the temperature distribution of melted surface was measured. With proper optical filters and the adjustment of aperture of lens, the radiation of melted surface was received by a ccd camera and its signal transferred to a computer. The real time monitoring of melted surface with a variation of electron beam Power was Possible and stable operation of electron beam was achieved. It was found that the max. temperature measured by a ccd camera with an assumption of blackbody radiation of melted Gd surface and adaption of Planet's law was above 100~$200^{\circ}C$ compared to that measured by a pyrometer in the same e-beam power.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.223-226
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• 2003

The best way in order to protect the system resource front Distributed Denial of Service(DDoS) attack is cut off the source of DDoS attack with path retracing the packet which transferred by attacker. Packet marking method can not use ICMP cause by using IP identifier field as marking field. And in case of increasing the number of router, retracing method using router ID has the size of marking field's increasing problem. In this paper, we propose that retracing method can be available the ICMP using marking field for option field in IP header and the size of making Held do not change even though the number of router is increased using the mark information which value obtained through XOR operation on IP address.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.721-723
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• 2007

Recently, the size and location of the acquired container image while the container is loading and unloading in Harbors is not fixed. And it is difficult to get a good image for recognition because of the variation of external environment as those the size of container and where the yard-tractor stop is. In this paper, we estimate where the container ISO-code set is using Top-hat transform from realtime images and get an image to recognize container ISO-code using PAN/TILT/ZOOM camera. We extract the container ISO-code using Top-hat transform and Histogram projection. After binarization, we extract each character from complex background using labeling. We use BP(Backpropagation Network) to recognize extracted characters.