GPU상에서 동작하는 Ray Tracing을 위한 효과적인 k-D tree 탐색 알고리즘

강윤식,박우찬,서충원,양성봉,Kang, Yoon-Sig,Park, Woo-Chan,Seo, Choong-Won,Yang, Sung-Bong 한국정보과학회 2008 정보과학회논문지 : 시스템 및 이론 Vol.35 No.3

This paper proposes an effective k-D tree traversal algorithm for ray tracing on a GPU. The previous k-D tree traverse algorithm based on GPU uses bottom-up searching from a leaf to the root after failing to find the ray intersected primitive in the leaf node. During the bottom-up search the algorithm decides the current node is visited or not from the parent node. In such a way, we need to visit the parent node which was already visited and the duplicated bounding box intersection tests. The new k-D tree traverse algorithm reduces the brother and parent duplicated visit by using an efficient method which decides whether the brother node is already visited or not during the bottom-up search. Also the algorithm take place bounding box intersection tests only for the nodes which is not yet done. As a result our experiment shows the new algorithm is about 30% faster than the previous. 본 논문은 GPU상에서 작동되는 ray tracing을 위한 효과적인 k-D tree 탐색 알고리즘을 제안한다. 기존의 k-D tree를 위한 GPU 기반 탐색 알고리즘은 임의의 단말노드에서 교차되는 primitive를 찾지 못한 경우. root 노드 방향으로 bottom-up 탐색하여 부모 노드에서 bounding box 교차검사를 이용해 형제 노드의 기 방문 여부를 판단한다. 이러한 방법은 이미 방문한 부모 노드의 방문과 bounding box 교차검사를 중복적으로 수행한다. 본 논문에서 제안하는 알고리즘은 bottom-up 탐색을 수행 할 때 형제노드가 이전에 방문했는지를 확인할 수 있는 효율적인 방법을 제시함으로써 형제노드 및 부모로드의 방문을 생략하도록 하고, 또한 아직 방문하지 않은 노드에 대해서만 bounding box 교차검사를 수행함으로써 중복된 연산을 피한다. 결과적으로 본 논문의 실험은 기존 알고리즘 대비 제안하는 알고리즘이 약 30%의 성능 향상이 있음을 보여 준다.

김수근에 대한 승효상 건축의 수정주의 행보 - 해럴드 블룸의 수정주의 변증법을 중심으로 -

강윤식,강훈,Kang, Yun-Sik,Kang, Hoon 한국건축역사학회 2014 건축역사연구 Vol.23 No.1

Architecture is a product of numerous influences, as shown in the apprenticeships of Kim, Jung-Up and Kim, Swoo-Geun with Le Corbusier's influences. Therefore, its identity is need to be re-defined based on such complex relationships. The rhetorical images of 'the Map of Misreading', as the core of the poetic identification proposed by Harold Bloom's 'the Theory of Influence', provide an efficient way of explaining the relations between architectural apprenticeships and identities. This research is to re-build a new methodology of architectural criticism based on it. The diachronic transformations of the architecture of Seung, Hyo-Sang also had very characteristic 'revisionary ratios' about his precursor Kim, Swoo-Geun. As an antithetic stance of his precursor's final phase, his early days works pursued continuously geometric abstraction and objective images of the architecture of Adolf Loos. However, his recent works are showing the obvious symptoms of regression to his origins. Finally, the architectural identity should be re-conceptualized as a complexity, based on inter-textuality from complex influences. This new architectural identity can be reflected into the modern obsessive identity.

전공의들의 전문직인식이 직업만족도에 미치는 영향

강윤식,감신,예민해,Kang, Yune-Sik,Kam, Sin,Yeh, Min-Hae 대한예방의학회 1997 예방의학회지 Vol.30 No.1

In ordo to investigate the professional job perception and job satisfaction of interns and residents and its related factors, the author conducted survey using self administered questionnaire for 2 months(August and September, 1996). The study subjects were 562 interns and residents who worked at one university hospital(tertiary hospital) and two general hospitals(secondary hospital) in Taegu, Korea. Among them, 297 (52.8%) responded completely. The results were as follows ; Respondents thought that people component was most important, science and status components were next among professional value scales which meant the desirable attitudes required to conduct professional works. But, the score of professional value scales was generally high and not affected by other variables in multiple linear regression analysis. They seemed to have very normative and ideal perceptions about professional values. The score of professionalism scales, which were attitudinal and behavioral traits about professional job, of high grade residents was significantly higher than that of interns and lower grade residents. The score of reference to professional organization and autonomy factor were increasing significantly as the grade increased. Working conditions and perception for socioeconomic status of doctors influenced the score of professionalism scale significantly. It seemed that professional socialization was made during the training periods of interns and residents. Most of respondents answered that current socioeconomic status of doctors were middle and high strata but they responded that the socioeconomic status of doctors would fall in the future. They seemed to have a pessimistic thought about doctor's status. Generally the respondents thought that they were satisfied with doctor job and fit to the job, but 51.9% answered that if possible they would get other jobs. It seemed to reflect their critical thinking on doctors' status. Perceptions about socioeconomic status of doctors, professional value and professionalism influenced job satisfaction significantly. The interns and residents had high sense of calling to doctors and thought that doctors were socially important job. Generally they were satisfied with their job. Interns and residents had normative thoughts about the trait which compentent doctors must have. During the training period, they seemed to have attitude and perception as a professional and to make professional socializations.

예방의학 영역에서 심신의학적 접근의 적용 가능성: 스트레스 관리를 위한 이완과 명상 기법을 중심으로

강윤식,Kang, Yune-Sik 대한예방의학회 2010 예방의학회지 Vol.43 No.5

Objectives: Emotional support and a stress management program should be simultaneously provided to clients as effective preventive services for healthy behavioral change. This study was conducted to review various relaxation and meditation intervention methods and their applicability for a preventive service program. Methods and results: The author of this paper tried to find various relaxation and meditation programs through a literature review and program searching and to introduce them. The 'Relaxation Response' and 'Mindfulness Based Stress Reduction (MBSR)' are the most the widely used meditative programs in mainstream medical systems. Abdominal breathing, Progressive Musclular Relaxation (PMR), Relaxative Imagery, Autogenic Training (AT) and Biofeedback are other well-known techniques for relaxation and stress management. I have developed and implemented some programs using these methods. Relaxation and meditation classes for cancer patients and a meditation based stress coping workshop are examples of this program. Conclusions: Relaxation and meditation seem to be good and effective methods for primary, secondary and tertiary preventive service programs. Program development and standardization and further study are needed for more and wider use of the mindbody approach in the preventive service area of medicine.

외래환자에서 금연 성공의 결정요인

강윤식,장정순,황영실,홍대용,김장락,Kang, Yune-Sik,Jang, Joung-Soon,Hwang, Young-Sil,Hong, Dae-Yong,Kim, Jang-Rak 대한예방의학회 2003 Journal of Preventive Medicine and Public Health Vol.36 No.3

Objective : This study was conducted in order to investigate predictors of smoking cessation in outpatients. Method : Subjects were 40f adult smoking patients who saw their doctors in the outpatient setting at a university hospital, regardless of their willingness of otherwise in smoking cessation. Physicians delivered a brief, stop smoking prompt to all patients who smoked one or more cigarettes a day. Then they referred to on-site counselors who provided a brief, nurse assisted intervention with a survey to a randomly assigned intervention group (200 smoking patients), whom the counselors telephoned later to prevent relapse or promote the motivation to quit, or gave only a survey to a control group (201 smoking patients). After at least 5 months, self-reported current smoking cessation was confirmed later using cut-off values of 7 ppm or less in expired alveolar air after breath holding portable CO analyzer. Results : After 5 months, subjects in the intervention group were 1.56 times (95% C.I. 0.89-2.73) more likely to quit smoking than those in the non-intervention group (14.0% vs. 9.0%). Willingness to quit smoking in a month, scheduled admission in a month, self efficacy score and FTND (Fagerstrom Test for Nicotine Dependence) score were all significantly related with smoking cessation. In stepwise multiple logistic regression, previous attempts to quit smoking were significant instead of self efficacy score. In the intervention group who had willingness to quit smoking in a month (132 smoking patients), FTND score, whether quit date was today, and whether quit promise paper was submitting were all significantly related with smoking cessation. In stepwise multiple logistic regression, scheduled admission in a month and whether quit date was today were significant predictor variables, Smoking cessation treatment should be tailored to individual smoking patients considering these predictors.

증례 : 인공호흡기를 이용한 전신마취하 발생한 종격동기종 ( Case Report : Pneumomediastinum Developed under Mechanically Ventilated General Anesthesia )

강윤식(Yeun Sig Kang),김영미(Young Mi Kim),전태완(Tae Wan Jeon),조경행(Kyung Haeng Cho),최영규(Young Kyoo Choi) 경희대학교 경희의료원 1996 慶熙醫學 Vol.12 No.2

자동차용 오일리저버 브라켓 설계를 위한 내구해석

강윤식(Yunsik Kang),손승완(Seungwan Son),강희용(Heeyong Kang),양성모(Sungmo Yang) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

In the part of break system components, the oil reservoir bracket is installed and related to the safety under various driving and thermal conditions including different ranges of acceleration. The robust design is required to predict the life cycle of the bracket. This paper presents VPD(Virtual Product Development) technique used to analyze the durability of an automotive oil reservoir bracket using CAE(Computer Aided Design). Since the durability test was performed using the dynamic model of oil reservoir & bracket, dynamic stresses are applied to predict the life cycle of component by MSC. Fatigue. Finally, the life cycle are obtained for the design modification of the automotive oil reservoir bracket.

구역화를 이용한 디지털 격자지형데이터의 단순화 알고리즘

강윤식(Yoon Sig Kang),박우찬(Woo Chan Park),양성봉(Sung Bong Yang) 한국정보처리학회 2000 정보처리학회논문지 Vol.7 No.3

In this paper we introduce a fast simplification algorithm for terrain height fields to produce a triangulated irregular network, based on the greedy insertion algorithm in [1, 4, 5]. Our algorithm partitions a terrain height data into rectangular blocks with the same size and simplifies blocks one by one with the greedy insertion algorithm. Our algorithm references only to the points and the triangles within each current block for adding a point into the triangulation. Therefore, the algorithm runs faster than the greedy insertion algorithm, which references all input points and triangles in the terrain. Our experiment shows that partitioning method runs from 4 to more than 20 times faster, and it approximates test height fields as accurately as the greedy insertion algorithms. Most greedy insertion algorithms suffer from elongated triangles that usually appear near the boundaries. However, we insert the four corner points into each block to produce the base triangulation of the block before the point addition step begins so that elongated triangles could not appear in the simplified terrain.

차량 배터리 케이스의 기밀성 시험기 평가

강윤식(Yunsik Kang),강희용(Heeyong Kang),이교우(Gyowoo Lee),양성모(Sungmo Yang),김민수(Minsoo Kim),이성기(Sungki Lee),김쾌만(Queman Kim) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Recently, weight reduction for an automobile component has been sought to achieve fuel efficiency and energy conservation. So many automobile components is producted by engineering plastic. Therefore this parts is important safety evaluation. In this paper, we presents effectiveness of leaking tester for safety evaluation in battery case made by injection molding. In oder to analyze the stress&displacement of this component, we need to conduct structure Finite Element Analysis. Test condition was decided using this work. And leaking tester is tested using test system, tester function was evaluation. Finally, it was conclude decision standard through results of test. Additionally, safety of impossible test condition is evaluated through FE analysis.

Proxy TCP ACK를 이용한 무선 환경에서의 TCP 성능향상 연구

강윤식(Yoonsik Kang),장주욱(Ju-wook Jang) 한국통신학회 1999 한국통신학회 학술대회논문집 Vol.1999 No.11