월페이퍼 그룹에 의한 한국 전통 문양의 분류

이상락(Sang-Rak Lee) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.4

Recently many works have been appeared to investigate traditional cultural contents from the viewpoint of science and mathematics. This paper aims to research and classify Korean traditional patterns by wallpaper groups in symmetry theory, and to disclose that what patterns exist in each group. We describe a brief explanation on the theory of symmetry group and wallpaper groups for understanding of this paper. Research for finding the patterns was accomplished through reference books on Korean traditional patterns. Classification results disclosed that each of 13 groups among 17 wallpaper groups has at least one pattern which belongs to them. But for the other 4 remaining groups we could not find any patterns for them. We also applied wallpaper group to the creation of several patterns to demonstrate that the wallpaper group are a useful idea for designing new patterns.

압전매트를 이용한 인원계수 알고리즘

이상락(Sang-Rak Lee),이지민(Ji-Min Lee),장시웅(Si-Woong Jang) 한국정보통신학회 2020 한국정보통신학회 종합학술대회 논문집 Vol.24 No.1

인공지능 : 전향 차분을 이용한 효율적 곡선 생성 알고리즘

이상락(Lee Sang Rak),심재홍(Sim Jae Hong) 한국정보처리학회 1994 정보처리학회논문지 Vol.1 No.2

곡선의 신속한 생성은 컴퓨터 그래픽의 고속 처리를 가능하게하는 중요한 기법 중의 하나이다. 이것은 현재 하드웨어나 소프트웨어를 통하여 상당한 효과를 거두고 있으나 급속한 그래픽의 발전을 보다 빠른 곡선 생성 방법을 요구한다. 본 논문은 전향 차분을 이용하므로써 곡선 상의 점의 좌표를 곱셈을 배제하고 덧셈만으로 계산하여 보다 빨리 곡선을 그릴 수 있는 한 알고리즘(CDAUD라 부름)을 제시한다. CDAUD는 곡선이 부드럽고 완전하게 연결된 상태로 그려지도록 하는 방안을 포함하고 있다. CDAUD의 시간 복잡도(time complexity)는 그리는 곡선에 따라 기존의 방법보다 우수한 경우도 있음을 실험을 통하여 확인할 수 있었다. Fast curve generation is one of important techniques which facilitate fast process of computer graphics applications. It is possible to resolve the task through hardware or software. But rapid development of computer graphics area need methods for more fast generation of curves. This paper propose a algorithm(called CDAUD), which computers the coordinates of points on curce only with add operations using forward differences and draw the curve fast. It also contains the method for generation of smooth and fully connected curves. Time complexity of CDAUD shows that it is superior than the existing method for constrained case, and it's superiority was validated through experimental implementation.

YOLO 인공지능 플랫폼을 이용한 이상행동 감시 시스템

이상락(Sang-Rak Lee),손병수(Byeong-Su Son),박준호(Jun-Ho Park),최병윤(Byeong-Yoon Choi) 한국정보통신학회 2021 한국정보통신학회 종합학술대회 논문집 Vol.25 No.1

본 논문에서는 YOLO 인공 지능 플랫폼을 이용하는 이상행동 감시 시스템을 구현하였으며, YOLO 시스템의 one-shot 감지 시스템 사용으로 기존 감시 시스템에 비해 우수한 응답 특성을 갖는다. YOLO 인공 플랫폼은 폭행, 절도, 방화와 같은 이상행동들로 구성된 이미지 세트로 학습되었다. 이상행동 감시 시스템은 서버와 클라이언트로 구성되어 있으며, 상용화될 경우 각종 범죄 문제를 풀기 위해 스마트시티에 적용이 가능하다. In this paper, abnormal behavior monitoring system using YOLO AI platform was implemented and had superior response characteristics compared to the conventional monitoring system using two-shot detection by using one-shot detection of YOLO system. The YOLO platform was trained using image dataset composed of abnormal behaviors such as assault, theft, and arson. The abnormal behavior monitoring system consists of client and server and can be applicable to smart cities to solve various crime problems if it is commercialized.

직선 선분의 대칭성을 이용한 수정 브레제남 직선 그리기 알고리즘

이상락(Lee Sang Rak),홍윤식(Hong Youn Sik) 한국정보처리학회 1999 정보처리학회논문지 Vol.6 No.8

A line segment has a symmetrical property about its midpoint. With this symmetrical property for a line segment we have proposed a variant of Bresenhnam's line drawing algorithm that selects two pixels at the same time. It implies that bi-directional line drawing toward the midpoint of line segment from each-end be possible. Besides, it can select two pixels using only one decision parameter, instead of two different parameters for each pixel. We also present a theoretical proof for the correctness of such a selection. Thus, we can reduce the time of generating line segment by approximately less than 5% compared to the Bresenham's method. Also, our experimental results show that the shape of line segment generated by the proposed approach is the exactly same as that of the Bresenham's method.

2 단계 다중버퍼 스위치에서의 스케줄링 알고리즘

이상락(Sang-Rak Lee),지남섭(Nam-Sub Ji),김영휘(Young-Hui Kim) 한국통신학회 2000 한국통신학회 학술대회논문집 Vol.2000 No.7

한국 전통 창문 문살의 컴퓨터 그래픽적 분석

이상락(Sang-Rak Lee) 한국정보기술학회 2008 한국정보기술학회논문지 Vol.6 No.5

This paper aims to reveal that procedural modelings and principles of computer graphics are useful for generation of patterns of Korean traditional window grille. For this purpose we analyzed the pattern of window grille. The results of analysis show that the patterns of window grille are based on such prototile as rectangle and hexagon, and that many of the window patterns can be generated using only rectangle prototile. This fact implies that the procedural modelling can be simplified. Implementation results show that many pictures of patterns of window grille can be generated using those prototiles. Especially some complicated-looking pattern can be generated using only rectangle prototile. We think that the ideas of this paper are very useful for generation, saving, reproduction and variation of pictures of window grille patterns.

전향 차분을 이용한 효율적 곡선 생성 알고리즘

이상락,심재홍,Lee, Sang-Rak,Sim, Jae-Hong 한국정보처리학회 1994 정보처리논문지 Vol.1 No.2

곡선의 신속한 컴퓨터 그래픽의 고속 처리를 가능하게 하는 중요한 기법 중의 하나이다. 이것은 현재 하드웨어나 소프트웨어를 통하여 상당한 효과를 거두고 있으 나 급속한 그래픽의 발전은 보다 빠른 곡선 생성 방법을 요구한다. 본 논문은 전향 차분을 이용하므로써 곡선 상의 점의 좌표를 곱셈을 배제하고 덧셈만으로 계산하여 보다 빨리 곡선을 그릴 수 있는 한 알고리즘(CDAUD라 부름)을 제시한다. CDAUD는 곡선 이 부드럽고 완전하게 연결된 상태로 그려지도록 하는 방안을 포함하고 있다. CDAUD 의 시간 복잡도(time complexity)는 그리는 곡선에 따라 기존의 방법보다 우수한 경 우도 있음을 실험을 통하여 확인할 수 있었다. Fast curve generation is one of important techniques which facilitate fast process of computer graphics applications. It is possible to resolve the task through hardware or software. But rapid development of computer graphics area need methods for more fast generation of curves. This paper propose a algorithm (called CDAUD), which computes the coordinates of points on curve only with add operations using for ward differences and draw the curve fast. It also contains the method for generation of smooth and fully connected curves. Time complexity of CDAUD shows that it is superior than the existing method for constrained case, and it's superiority was validated through experimental implementation.

젖소분뇨와 Crude Glycerin의 통합혐기소화

이새민,이상락,Lee, Sae-Min,Lee, Sang-Rak 한국축산환경학회 2013 한국축산시설환경학회지 Vol.19 No.2

In this study, the mixture ratio included 20% (GLY 20), 40% (GLY 40), and 60% (GLY 60) based on VS with the control group (GLY 0) with no crude glycerin added. Maintaining stable pH, GLY 20 and GLY 0 showed the highest total output of biogas (1.24 L/L/d) and methane(0.78 L/L/d) as its volatile solids reduction rate was 53.56%. In case of GLY 40 and GLY 60, their pH was rapidly reduced after seven days of the study, so that their anaerobic digestion was all stopped.In the results of the study, it is desirable to add crude glycerin less than 20%, and it would be necessary to have the future researches on more detailed organic loading rate of each ratio, and analysis on economic feasibility.

고상 가축 분뇨 자원화를 위한 데이터베이스 구성에 따른 분뇨특성, 분석방법 및 바이오가스 평가 방법에 대한 고찰

최용준,이상락,Choi, Yong-Jun,Lee, Sang-Rak 한국축산환경학회 2015 한국축산시설환경학회지 Vol.21 No.1

The livestock manure recycling have been performed worldwide because of its environmental and economic benefits. However, domestic standard protocol was nothing for high solid manure. Therefore, This paper was conducted to review database configuration of manure characteristics, analysis methods, bio-methane potential test for high solid manure recycling. In American society of agricultural engineers standard, manure characteristics indicated about sort of thirty types. This is important information to determine for manure recycling method. Furthermore, in order to determine exact manure characteristics recommended that synchronized chemical analysis method among studies. Bio-methane potential tests are widely performed in studies about estimation of organic substrates methane production. Although various methods and parameters were used, was no standard protocol and guideline in domestic. Bio-methane potential test methods and parameters were reviewed through various researches. Consequently, this paper is expected that assist to additional studies and manure characteristic database.