LED 광원 크기에 따른 자유 형상 렌즈의 조명 성능 변화와 공차 특성

양재석,김대찬,오범환,박세근,유일현,이승걸,Yang, Jae-Suk,Kim, Dae-Chan,O, Beom-Hoan,Park, Se-Geun,You, Il Hyun,Lee, Seung Gol 한국광학회 2013 한국광학회지 Vol.24 No.1

본 논문에서는 점광원을 기준으로 설계된 자유 형상 렌즈(freeform lens)의 조명 성능과 LED 광원 크기와의 관계 및 공차 특성을 살펴보았다. 비교를 위해 발산 조명 모델(divergent illumination model)을 적용한 두 가지 렌즈와 중첩 조명 모델(overlapped illumination model)을 적용한 한가지 렌즈를 설계하였다. LED 광원이 커짐에 따라 평균 조도에 비해 조도 균일도가 상대적으로 크게 감소하였으며, 정렬 오차에 의한 성능 저하는 거의 발생하지 않았다. 하지만 LED 광원의 방출 특성 변화는 LED 광원 크기에 관계없이 조명 성능에 영향을 미치는 것으로 확인하였다. 발산 조명 모델로 설계된 렌즈가 전반적으로 우수한 성능을 보였지만, LED 방출 특성 변화에 대해서는 중첩 조명 모델로 설계된 렌즈의 성능이 상대적으로 적게 변화함을 알 수 있었다. In this paper, the illumination performances of three freeform lenses optimally designed for a point source were investigated for several LEDs with different source sizes, and also the tolerance characteristics of the lenses were analyzed. For comparison, two lenses with different sizes were designed with a divergent illumination model, and the last one was done with an overlapped illumination model. As the LED source size increased, the illuminance uniformity decreased more strongly, and the influence of a source misalignment on illumination performance became insignificant. However, the variation of LED radiation characteristics had strong effect on the illumination performance, irrespective of LED source size. Even though the lens based on a divergent illumination model showed superior performance compared to the lens based on an overlapped illumination model, the latter was less sensitive to the variation of LED radiation characteristics.

Erbium YAG 레이저 조사 후 Guinea Pig 피부에서 관찰된 조직학적 변화

양재석,계영철,김수남 ( Jae Seok Yang,Young Chul Kye,Soo Nam Kim ) 대한피부과학회 1997 大韓皮膚科學會誌 Vol.35 No.4

Background: Laser resurfacing has beneficial effects in the treatment of several skin problems such as acne and chicken pox scars. Recently pulsed erbium YAG laser has been used for skin resurfacing, but not enough is known about the scientific basis of such treatment. Objectiye : The purpose of the study was to assess the macroscopic and microscopie changes after irradiation with the pulsed Er-YAG laser. Methods : We did two tests on guinea pig skin, First, the laser was used to irradiate the skin of a guinea pig with the intensity of 500 mJ, 5 watt until pinpoint bleeding began. Skin biopsies were performed immediately, one, two and four weeks after the irradiation. Second, the laser was used to irradiate the skin of a guinea pig with the intensity of 300mJ(3watt), 500mJ(5watt), 700mJ(7watt) until pinpoint bleeding began, Skin biopsies were examined immediately, one, two and four weeks after the irradiation. Results : 1. Histological changes to the dermis over time after laser irradiation with 500 mJ, 5 watt are as follows: After one week, complete reepithelization and proliferation of the blood vessels within the dermis occured. A reaction of th dermis which consisted of newly formed collagen and was distinguisbed from the lower dermis was also examined. The reaction was rnost active after two weeks and lasted up to four weeks. 2. Histological changes to the dermis over time after laser irradiations with different intensities of 300 mJ(3watt), 500 mJ(5watt), and 700 mJ(7watt) are as follows : In all the cases of laser irradiation with different intensities, edema, neovascularization and fine collagen fiber in the upper dermis were observed. At higher intensities, the dermal reactions were stronger and were sustained for a longer time. Conclusion : Pulsed erbium YAG laser had effects on the epidermis and dermis. Therefore, pulsed erbium YAG laser can be used for skin resurfacing effectively and safely. (Kor J Dermatol 1997;35(4): 851-659)

한국 대학생의 영어 읽기 관련 어휘학습전략에 대한 연구

양재석 ( Yang Jaeseok ) 한국현대언어학회 2017 언어연구 Vol.33 No.1

This study investigated the underlying patterns of reading related vocabulary learning strategies and their relationship to vocabulary size. Based on data, from 344 college-level EFL students, which reported the reading-related vocabulary learning strategies in relatin to the students curent vocabulary size, the findings highlighted six types of strategies. These strategies were explained in relatin to the findings and theoretical aspects of previous research. Of these strategies, word noticing is the most frequently used strategy, followed by guessing strategy, extended strategy, confirmation strategy, form and meaning-related strategy, and memory strategy. The use of reading related vocabulary learning strategies in relation to the vocabulary size, showed that participants with bigger vocabulary size tended to use strategies more frequently than those with smaller vocabulary size. The findings showed three strategies (form & meaning, guessing, and word noticing strategies) have the greatest ability to predict vocabulary size. (Daegu National University of Education)

ESL 학습자의 학문적 읽기에서 나타난 어휘학습전략의 비교연구

양재석(Jae seok Yang) 학습자중심교과교육학회 2015 학습자중심교과교육연구 Vol.15 No.5

이 연구는 ESL 학습자들을 대상으로 L2 학문적 읽기 과정에서 나타나는 어휘학습전략을 비교 연구하였다. 총 8명의 참여자는 어휘규모수준과 전략사용 빈도의 결과를 바탕으로 네 개의 집단으로 구성하였으며, 각각 학업적 읽기를 실시하여 전략사용양상을 질적분석하였다. 어휘수준 시험(Vocabulary Size Test), 사전-사후 심층 면접, 관찰노트, 사고구술법 (think-aloud protocol)에서 수집된 자료를 바탕으로 분석한 주요 결과, 전략사용이 높고 상위수준의 어휘실력을 가진 학습자들의 경우 다수의 전략을 순차적이고 조합적인 방식으로 사용할 뿐만 아니라 학습자 개개인의 사전지식과 필요 및 과업의 특징에 따라 전략을 사용하는 것으로 나타났다. 반면에 전략사용이 낮은 학습자들의 경우 단편적이며 비순차적으로 어휘전략을 사용하였다. 학업적 읽기에서 어휘학습자의 전략적 학습행동 양상 및 특징에 대한 연구결과를 바탕으로 ESL 읽기교육에 적용할 수 있는 방안을 모색하였다. This study describes how tertiary ESL speakers having different vocabulary proficiency and strategy use take strategic approaches to learn vocabulary when they are engaged in L2 academic reading. Depending on their VLS use and vocabulary size level, eight participants were divided into four groups. Based on the data collected from the Vocabulary Size Test (VST), pre and post-task interviews, observation notes, and think-aloud protocols, the key findings revealed that the highly active strategy users having high vocabulary proficiency tend to orchestrate multiple strategies in a combinatorial or sequential fashion. This in turn depended on the task, needs, and prior knowledge of these users. On the other hand, the less active strategy users were inclined to employ isolated and non-sequential strategy in L2 reading. This implies that vocabulary instructors should encourage users with less active strategy to broaden their repertoire of strategies and use them in sequential ways to compensate for their lower vocabulary knowledge in L2 academic reading.

후기 분만 후 자간증 1례

양재석 ( Jae Seok Yang ),김수경 ( Soo Kyung Kim ),전영미 ( Young Mi Jeon ),홍서유 ( Soe You Hong ),박철홍 ( Cheol Hong Park ),신정환 ( Jung Hwan Shin ) 대한주산의학회 2003 Perinatology Vol.14 No.3

산전 진찰의 기술이 발달하고 자간증의 발생 비율이 점차 감소하고 있으나, 후기 분만 후 자간증의 발생률은 증가하는 양상을 보이며 그 예방도 쉽지 않다. 더구나, 분만 전에 전자간증의 증세가 전혀 없는 경우는 후기 분만 후 자간증의 진단과 예방이 어렵다. 본원에서는 분만 전에 전자간증으로 진단 받지 않았던 산모가 조산으로 분만 후 7일째 경련 등 자간증의 증세를 보인 후기 분만 후 자간증 1례를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Although the technique of antenatal care is developed, the incidence of late postpartum eclampsia has been increased and its prevention is difficult. In addition, the diagnosis is more difficult if the patient did not show any symptoms of preeclampsia before delivery. We described one case of late postpartum eclampsia that occurred on 7th day after preterm delivery and has not been diagnosed before delivery including a review of this literature.

항에리트로포에틴 (Anti-erythropoietin) 항체에 의한 진성 적혈구계 무형성증 (Pure Red Cell Aplasia) 2예

양재석 ( Jae Seok Yang ),이정은 ( Jung Eun Lee ),박동준 ( Dong Jun Park ),성은영 ( Eun Young Seong ),주권욱 ( Kwon Wook Joo ),안규리 ( Cu Rie Ahn ),한진석 ( Jin Suk Han ),김성권 ( Suhng Gwon Kim ),조한익 ( Han Ik Cho ),이정상 ( Ju 대한신장학회 2004 Kidney Research and Clinical Practice Vol.23 No.5

한국 대학생의 영어 글쓰기 능력과 글쓰기 전략의관계에 대한 연구

양재석(Yang, JaeSeok) 미래영어영문학회 2016 영어영문학 Vol.21 No.1

This study investigates the relationship between English writing performance and writing strategy use by college-level EFL students in Korea. The data of English writing scores and writing strategy questionnaire were collected from 40 EFL students taking English writing course in a university in Kyungnam area. The result of overall strategy use showed that cognitive strategy is the most frequently used strategy. Specifically, revision strategy is the most frequently used among other cognitive strategies. Moreover, English writing scores and writing strategy use are positively correlated. The result of stepwise multiple regression analysis indicates that two of cognitive strategies including revision and resourcing strategies have the most ability to predict English writing score among seven strategies. Therefore, it is suggested that teachers need to provide feedback to EFL writers in order to encourage them to participate actively in self-editing and revision in the writing process. Additionally, EFL writers need to be more aware of using alternative strategies to address their linguistic or lexical difficulties, rather than overly relying on using resources while performing L2 writing tasks.

인도네시아 자카르타에서의 폐기물 거버넌스의 신자유주의화와 불균등한 쓰레기 배분

양재석(Jea-surk Yang) 대한지리학회 2023 대한지리학회 학술대회논문집 Vol.2023 No.06

ABO 혈액형 부적합 신장이식

양재석 ( Jae Seok Yang ) 대한신장학회 2011 Kidney Research and Clinical Practice Vol.30 No.4

K-근접 시설 접근성을 이용한 도시 스프롤 측정

양재석(Jeasurk Yang) 대한지리학회 2017 대한지리학회지 Vol.52 No.4

도시 스프롤은 장기적인 계획을 통해 관리해야 할 도시 문제로, 이를 위해서는 측정 방법의 개발이 필수적이다. 여러 방법들 가운데 접근성을 이용한 측정 방법은 기능 기반 측정 방법이라는 점에서 주목할 만하다. 다만 접근성을 이용한 측정은 아직 방법론적으로 보완될 점이 많다는 점에서 한계가 있다. 본 연구에서는 접근성측정 방법이 다섯 가지 측면(근접 시설, 시설의 계층성, 주변 시가지 영향, 분석 단위, 수요)에서 보완 가능하다고 주장한다. 본 연구의 목적은 앞서 언급한 측면들을 보완하기 위해, 근접 시설 접근성을 이용한 도시 스프롤 측정 방법을 개발하는 것이다. 본 연구는 이를 ‘K-근접 시설 접근성’이라고 정의하고 춘천시를 사례로 적용한다. 본 연구의 함의는 다음과 같다. 첫째, 본 연구는 다섯 가지 측면에서 접근성 계산 방식을 보완하여 스프롤을 보다 정밀하게 측정하는 방법을 개발하였다. 둘째, 근접 시설이라는 요소를 추가함으로써 주민들의 시설 이용 행태를 스프롤 논의에 반영하였다. 셋째, 주택 건물이라는 분석 단위에서 스프롤을 측정함으로써 국지적인 수준에서의 정책 입안을 가능케 한다. Urban sprawl is one of urban problems that need to be managed and controlled through long term planning with developing methods of measurement. Above all, the method using accessibility is meaningful as it is a function-based approach. However, there is a limitation in that it is not yet sufficiently completed methodologically. This study argues that existing accessibility methods can be adjusted in five aspects(near facilities, the hierarchy of facilities, the effects of adjacent urban area, an analysis unit, and demand). The purpose of this study is to develop a method of measuring urban sprawl by the concept of the near facilities to complement the above five aspects. The study defines this as K-nearest facility accessibility and uses Chuncheon city as a case study. The implications are as follows. First, it provides a more precise way of measuring sprawl with accessibility in five aspects. Second, it reflects the behavior of residents using urban facilities by considering the aspect of the near facilities. Third, it provides local-scale policy guidance for management by using residential buildings as an analysis unit.