• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.311-312
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• 2012

본 발표에서는 광학적 분석 시스템에 적용 가능한 발광소자(광원)과 수광소자(광센서)를 집적화시키는 모듈(수 발광 집적모듈) 기술을 제시하고자 한다. 이러한 수-발광 집적모듈은 다양한 응용 분야에 적용 될 수 있다. 예를 들어, 광신호 감지를 위한 광통신용 송-수신 모듈(optical communication), 의료/진단 분야에서 단백질/DNA/박테리아 등의 검출 및 분석에 관한 바이오 센서(bio-sensor), 그리고 대기(가스)/수질 모니터링에 관한 환경센서 등 매우 광범위한 분야에 해당되는 요소 기술이라 할 수 있다. 특히, 이들 분야들 중 바이오 물질을 분석하고 검출하는 광학적 바이오 센서 기술은 높은 경제적 가치와 산업적 성장 잠재력으로 인해 오랫동안 활발한 연구가 진행되어 오고 있다. 이러한 광학적 바이오 센서에서 가장 범용적인 방법 중 하나가 항온-항체 면역반응을 기반으로 하는 형광 검출(fluorescence detection) 기법이다. 이러한 시스템은 전체적으로 광원, 광학계, 그리고 센서로 구성되는데 기존에 일반적으로 사용되고 있는 형광 현미경의 경우는 민감도가 우수하다는 장점은 있으나 상당히 고가이고 부피가 크며 복잡한 광학구성으로 이루어져 있다는 한계점을 가지고 있다. 이러한 맥락에서 고민감도를 확보하면서 휴대성, 고속처리, 저가 등의 특성을 가진 시스템에 대한 요구가 갈수록 증가하고 있다. 이를 해결하기 위한 핵심기술 중의 하나가 수-발광 부분을 집적화 시키는 기술이라 할 수 있다. 본 연구에서는 바이오 센서 기술의 하나로서 형광을 측정하여 혈액내의 진단 지표인자를 검출할 수 있는 휴대용 혈액진단기기에 적용되는 소형 수 발광 집적 모듈을 개발하였다. 혈액내의 검출 성분의 양에 따라 형광의 세기가 변화하게 됨으로써 정량적인 검출이 가능한 원리이다. 모듈의 구조는 크게 광원(발광소자), 광학계, 그리고 광센서(수광소자) 세 영역으로 나누어 진다. 광원은 635 nm 적색 레이저다이오드로서 형광체(Alexa Fluor 647/발광파장: 668 nm)를 여기 시키는 기능을 하며 장착된 볼렌즈 의해 샘플의 형광체 영역으로 집광된다. 광학계는 크게 시준렌즈(collimating lens)와 광학필터로 구성됨으로써 샘플로부터 발생되는 광을 적절하게 수광소자로 전달하는 기능을 하게 된다. 여기서 광학필터의 경우는 기본적으로 Distributed Bragg's Reflector(DBR) 구조로써 실리콘(Si) 포토다이오드 상부에 모노리식(monolithic)하게 형성되며 검출 샘플로부터 진행되는 레이저 광(잡음의 주원인)은 차단하고 형광(광신호)만 통과 시키는 기능을 하게 된다. 따라서 신호 대 잡음비(S/N ratio)를 향상시키기 위해서는 정밀한 광 필터링 기능이 요구됨으로써 박막의 세밀한 공정 조건과 구조적-광학적 특성 분석이 수행되었다. 마지막으로 포토다이오드 소자는 일반적인 구조 이외에 중앙에 원형 구멍이 형성된 특별한 구조가 적용된다. 이것은 포토다이오드 구조에 변화를 줌으로써 모듈 구조를 효율적으로 응용할 수 있다는 의미를 갖는다. 또한 포토다이오드의 전기적-광학적 측정 분석을 통해 잡음 및 감도 특성이 세부적으로 조사되며 형광신호를 효과적으로 측정할 수 있음을 확인하였다. 최종적으로 제작된 모듈은 약 $1{\times}1{\times}1cm^3$ 내외 정도의 크기를 갖는다. 요약하자면 본 발표에서는 광학적 바이오센서에 적용할 수 있는 소형 수-발광 소자 집적모듈을 소개한다. 전체 모듈 설계는 최소한의 부피를 가짐과 동시에 측정의 정밀성을 향상시키는데 초점을 맞추어 진행하였다. 세부요소인 광학필터와 포트다이오드의 경우 잡음 및 민감도에 미치는 중요성 때문에 세밀한 공정 및 특성분석이 수행되었다. 결론적으로 독자적인 설계 및 공정을 통해 휴대성 및 정밀성 등의 목적에 부합한 경쟁력 있는 수-발광 소자 집적모듈 제작 기술을 확보하였다.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.515-521
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• 2013

The objective of this study was to estimate the changes of stand structure before and after applying the three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. This study has been conducted in the natural deciduous forests in Pyeongchang of Gangwon Province, Korea. Nine permanent sampling plots of 0.09 ha were established in the forests and each of the three silvicultural treatments was applied to three sampling points. Some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after applying the silvicultural treatments. In this study, a competition index was used to analyze the differences among structures of stands managed by three different silvicultural treatments. Hegyi's distance-dependent competition index was estimated and compared to analyze the differences of stand structures among the stands before and after silvicultural treatments. A method using a height angle $50^{\circ}$ from the base of the subject tree was adopted as the selection method of competitor trees. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand structure among the stands. The results revealed that competition status among trees in the stand seems to be improved after applying the silvicultural treatments. There are significant differences in the competition index between before and after silvicultural treatments for each stand. According to the evaluation of competition index, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.34-40
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• 2004

In this paper, we have studied the OCT(Optical Coherence Tomography) system which has been advantages of high resolution, 2-D cross-sectional images, low cost and small size configuration. The characteristics of light source determine the resolution and coherence length. The light source has a commercial SLD with a central wavelength of 1,285 ill11, 35.3 nm(FWHM). The optical delay line is necessary to make equal with the optical path length to scattered light or reflected light from a sample. In order to make equal the optical path length, the stage that is attached to a reference mirror is controled by a step motor. And the interferometer is configured with the Michelson interferometer by using a single mode fiber, and the scanner can be focused on the sample by using a reference ann Also, the 2-dimension cross-sectional images were measured with scanning the transverse direction of the sample by using a step motor. After detecting the internal signal of lateral direction, a scanner is moved to obtain the cross-sectional image of 2-dimension by using step motor. A photodiode, which has high detection sensitivity and excellent noise characteristics has been used. The detected small signal has a noise and interference. After filtering and amplifying the signal, the output signal is demodulated the waveform And then, a cross-sectional image is seen through converting this signal into a digitalized signal by using an AID converter. The resolution of the sample is about 30${\mu}{\textrm}{m}$, which corresponds to the theoretical resolution. Also, the cross-sectional images of onion cells were measured in real time scheme.

• Progress in Medical Physics
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• v.21 no.1
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• pp.99-112
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• 2010

In Republic of Korea, there are many Quality Assurance protocol for general radiation treatment machine such as linac. However, Quality Assurance protocol for radiosurgery treatment system is not ready perfectly. One of the radiation treatment machine for radiosurgery, novalis system needs to suitable Quality Assurance protocol for using it right way during radiation treatment and maintaining suitable accuracy for daily, weekly, monthly and annually periods. Therefore, in this article, we develop Quality Assurance protocol for novalis system. We collected and analysed domestic and foreign novalis Quality Assurance protocol. After that, we selected essential QA items and each tolerance range for developing proper QA protocol, and we made anatomical phantom for execution of selected QA items and evaluation of overall state of QA, and then, we use this measured value as a reference. Quality Assurance items are consisted of Mechanical accuracy QA part and Radiation delivery QA part. Mechanical accuracy QA part is comprised of radiation generation machine part, assistive devices part and multi-leaf collimator part. Radiation delivery QA part is divided into radiation isocenter accuracy and dosimetric evaluation. After that, developed novalis QA tables are made by using these QA items. These novalis QA tables would be used to good standard in order to maintain apt accuracy for radiosurgery in daily, weekly, monthly and annually periods.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.92-97
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• 2002

A real-time OTF (optical transfer function) measuring system with on- and off-axis nodal slide bench type for the camera lens is fabricated and evaluated. It consists of a nodal slide bench including a T-bar for the OTF measurement of an off-axis object, two dimensional CCD (charge coupled device) with pixel of 9.9${\mu}{\textrm}{m}$$\times$9.6${\mu}{\textrm}{m}$ for real-time OTF measurment, and a collimating lens of focal length of 300 mm for the optimization of this system. The OTF system is corrected by using the OTF of a SIRA lens of fnumber of F/8 and focal length 50 mm. In order to confirm the reliability of the OTF system, two MTFs (modulus transfer functions) of CCTV & VIDEO lens (JAPAN, AVENIR-SE 2514) of focal length of 25mm and field of view 10.6$^{\circ}$are measured by the camera bench type OTF system of reference OTF system and the nodal slide bench type OTF system and compared with each other. As a result, these two values are agree well with each other within 4% from 0 1p/mm to 100 1p/mm.

• The Journal of the Petrological Society of Korea
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• v.9 no.4
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• pp.205-210
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• 2000

Measurements of phase identification and degree of orientation for fine-grained (about 0.3 mm in diameter) minerals in rock samples performed by micro-area X-ray diffractometer.$Al_{2}SiO_{5}$ polymorphs (andalusite, kyanite and sillimanite) were chosen for the measurements and target minerals were existed on thin sections. Micro-area X-ray diffractometer is composed of 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillating goniometer and position sensitive proportional counter (PSPC). $CuK_{\alpha}$ radiation was used as X-ray source and a pin hole ($50\;\mu\textrm{m}$$ in diameter) collimator was selected to focus radiation X-ray onto the target minerals. Phase identification and diffracted X-ray peak indexing were carried out by 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillation measurement. Then, 2(${\omega}\;{\phi}$)-circle oscillation measurement was made for the purpose of searching the prevailing lattice plane of the minerals on thin section surface. Finally, for a selected peak by 2-circle oscillation measurement, X-ray pole figure measurement was executed for the purpose of check the degree of orientation of the single lattice direction and examine its pole distribution. As a result of 3-circle oscillation measurement, it was possible that phase identification among $Al_{2}SiO_{5}$ polymorphs. And from the results of 2-circle oscillation measurement and X-ray pole figure measurement, we recognized that poles of andalusite (122), kyanite (200) and sillimanite (310) lattice plances were well developed with direction normal to each mineral surface plane respectively. Therfore, the measurements used with micro-area X-ray diffractometer in this study will be a useful tool of phase identification and degree of orientation measurement for fine-grained rock forming minerals.

• The Korean Journal of Financial Management
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• v.10 no.1
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• pp.199-229
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• 1993

본 연구(硏究)는 선물거래의 선진국이라고 할 수 있는 미국(美國), 영국(英國), 일본(日本)등을 대상으로 선물계약(先物契約)의 증거금변경(證據金變更)이 시장활동(市場活動) 즉 거래량(去來量), 미결제포지션(open interest), 가격변동성(價格變動性)에 미치는 영향(影響)을 만기별(滿期別)로 구분하고 또한 시계열(時系列) 현상(現狀)을 제거한 후 비교분석(比較分析)함으로써 이러한 분석결과를 토대로 우리나라가 주가지수선물을 도입하는데 있어서 차후의 증거금관리(證據金管理)에 대한 하나의 정책적(政策的) 방향(方向)을 제시(提示)하고자 하였다. 연구결과(硏究結果)를 요약(要約)하면 증거금(證據金)은 시장활동(市場活動)인 거래량(去來量)과 선물계약(先物契約)의 수요(需要) 즉 미결제포지션에는 상당한 영향(影響)을 미치나 가격변동(價格變動)에 미치는 영향은 미약하며 그러한 효과는 비교적 단기적(短期的)인 것으로 밝혀졌다. 아울러 그러한 효과는 국가간(國家間) 및 상품간(商品間)에 큰 차이 없이 거의 공통적(共通的)인 현상(現狀)임이 밝혀졌다. 구체적으로 본 연구가 시사하는 바는 연구결과(硏究結果) 중 증거금변경(證據金變更)에 따른 미결제포지션의 움직임을 거래량(去來量)과 연관(聯關)시켜 생각해 볼 때 증거금인하시(證據金引下時) 단기에 거래량이 유의적으로 증가하면서 동시에 미결제포지션이 유의적으로 증가하는 것으로 보아 증가되는 많은 거래량은 선물시장 참여자들이 새로운 포지션을 취하기 때문인 것으로 보여진다. 이러한 사실은 거래소가 증거금인하(證據金引下)를 통하여 잠재적인 시장참여자들의 비용(費用)을 낮춤으로써 시장유동성(市場流動性) 제고(提高)를 유도하는 경우 이러한 시도는 단기적(短期的)으로는 어느 정도 효과(效果)를 거둘 수 있음을 시준(示晙) 한다. 또한 증거금변경이 가격변동성(價格變動性)에 미치는 영향은 크지 않은 것으로 밝혀져 일반적으로 선물거래소들이 취하고 있는 증거금정책으로써 가격변동성을 관리하기 위한 증거금(證據金) 운용정책(運用政策)은 적어도 단기에 있어서는 어느 정도 효과를 보나 그 효과는 크지 않은 것으로 판단된다. 이러한 사실들은 증거금변경이 이루어지는 시점이 일반적으로 시장활동(市場活動)의 변화(變化)가 나타나기 시작한 후 1개윌 이내에 이루어져 왔다는 사실을 고려한다면 많은 선물거래소들이 취하고 있는 증거금관리정책은 비교적 단기적인 효과를 위한 것이며 그러한 정책(政策)들은 나름대로 소기의 목적(目的)으로 달성하고 있는 것으로 보인다. 끝으로 증거금변경이 선물시장활동에 미치는 효과의 국가간(國家間)의 차이(差異)가 없고 또한 상품간(商品間)에도 사실상 차이(差異)가 없다는 사실은 앞으로 선물시장을 개설할 우리나라의 입장에서 볼 때 선물증거금(先物證據金) 운용(運用)에 관한 정책수립시(政策樹立時) 금융선진국(金融先進國)의 증거금(證據金) 정책운용(政策運用)을 통한 시장관리(市場管理) 경험(經驗)을 어느 정도 참고할 수 있음을 시사한다고 할 것이다.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.521-529
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• 2016

Since Gamma Knife(R) radiosurgery(GKRS) is based on a single-fraction high dose treatment strategy, independent verification for the results of Leksell GammaPlan(R) (LGP) is an important procedure in assuring patient safety and minimizing the risk of treatment errors. Several verification methods have been developed and reported previously. Thus these methods were tested statistically and tried on Leksell Gamma Knife(LGK) target treatments through the embodiment of the previously proposed algorithms(PPA). The purpose of this study was to apply and evaluate the accuracy of verification methods for LGK target treatments using PPA. In the study 10 patients with intracranial lesion treated by GKRS were included. We compared the data from PPA and LGP in terms of maximum dose, arbitrary point dose, and treatment time at the isocenter locations. All data were analyzed by Paired t-test, which is statistical method used to compare two different measurement techniques. No statistical significance in maximal dose at 10 cases was observed between PPA and LGP. Differences in average maximal dose ranged from -0.53 Gy to 3.71 Gy. The arbitrary point dose calculated by PPA and LGP was not statistically significant too. But we found out the statistical difference with p=0.021 between TMR and LGP for treatment time at the isocenter locations. PPA can be incorporated as part of a routine quality assurance(QA) procedure to minimize the chance of a wrong overdose. Statistical analyses demonstrated that PPA was in excellent agreement with LGP when considering the maximal dose and the arbitrary point dose for the best plan of GKRS. Due to the easy applicability we hope PPA can be widely used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1863-1872
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• 2010

Researches recently made in advanced countries into entrepreneurship found that various resources and information are mainly provided to ventures through social capital, which is a resource capital based on a network, and through corporate entrepreneurship. This research is an exploratory study on the effects of social capital and corporate entrepreneurship of new ventures upon their corporate performance, conducted from the standpoint of dynamic capability. For that purpose, a questionnaire investigation was made of 171 venture entrepreneurs in Korea, and the following are the results of an empirical analysis of responses to the questionnaire. First, it was found that social capital, which is a resource capital based on a network, had a significant effect on corporate entrepreneurship. Second, social capital also had a significant effect on ventures corporate performance. Third, corporate entrepreneurship had a significant effect on corporate performance. These results imply that social capital and corporate entrepreneurship have a significant effect on the corporate performance of ventures, which have innate disadvantages concerning the supply of resources. On the other hand, ventures, which encounter relatively more intense demands for change and renovation, can be managed in a sustainable manner just when they adequately accumulate their social capital and utilize their external resources and appropriately conduct their corporate entrepreneurship activities.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.255-264
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• 2022

The conventional spot-type UV curing machine configures a collimator optical system using a plurality of lenses so that the light beam is incident through an optical cable. In order to increase the transmission light efficiency, a collimator optical system composed of three or more lenses is required, and accordingly, it is difficult to align the optical system, and it is difficult to implement the system compactly. In this study, a single TIR lens collimator that can realize the same level of spot diameter and light efficiency as the conventional collimator optical system composed of three lenses was designed. Through this, the light efficiency at the curing area with the minimum illuminance deviation was 33.2 %, which was similar to the performance of the reference collimator optical system, and the illuminance deviation on the curing area was 18.8 %, ensuring acceptable performance. In addition, by arranging a fly-eye lens with field flattening function at the front end of the condensing lens, the effective curing area diameter was reduced from 5.0 mm to 3.0 mm, enabling higher curing energy density to be realized. In addition, it was confirmed that the illuminance deviation can be greatly improved to a level of 14.4%.