Specular Reflection을 고려한 Angle Interpolation Shading 알고리즘

김화성(Hwa-Sung Kim),공창환(Chang-Hwan Kong),김창헌(Chang-hun Kim) 한국정보과학회 1997 한국정보과학회 학술발표논문집 Vol.24 No.2Ⅱ

Angle interpolation shading 알고리즘은 angle을 interpolation시켜 phong shading의 속도를 gouraud shading 속도에 근접시키려는 알고리즘이다. 이 방식은 specular reflection을 1차원적으로 계산하기 때문에, polygon 내부의 highlight를 정확히 표현하지 못하는 단점이 있다. 본 논문은 highlight를 적절히 표현하며, angle interpolation 알고리즘과 속도가 비슷한 방법을 제안한다. 본 방법은 물체의 specular reflection을 반영하기 위해 두 개의 각을 정의한다. 이 두 개의 각과 lookup table를 통해 intensity 계산량을 획기적으로 줄일 수 있다. 실험을 통한 성능 평가결과 본 알고리즘은 gouraud-phong shading보다 빠르며, phong shading 수준의 image quality를 유지한다.

디지털 치과 성형 수술 계획 시스템

윤광희(Kwang-Hee Youn),박정현(Jung-Hyun Park),공창환(Chang-Hwan Kong),김창헌(Chang-Hun Kim) 한국정보과학회 1998 한국정보과학회 학술발표논문집 Vol.25 No.1B

본 연구의 목적은 치과의 성형 환자 수술 계획에 있어서 수술 후 얼굴뼈의 위치 변화에 따른 외형의 변화를 영상으로 예측하여 주는 치과 성형 수술 계획 지원 시스템의 개발이다. 악안면 기형 환자에게 적용되는 이 시스템에서는 수술 후 얼굴의 형태 변화를 얼마나 정확하고 편리하게 예측할 수 있느냐 하는 것이 주된 관심사이다. 본 시스템은 X-ray 영상을 이용하여 안면골의 주요부분을 추출하고 환자의 측면사진을 이용하여 얼굴의 측면 윤곽선 및 특징점을 추출한다. 안면 골격중 상악골과 하악골의 이동 방향과 정도를 시술자가 수술 계획시 지정하면 연조직 변화 예측 함수와 워핑 기법을 이용하여 수술 후 환자의 모습을 영상으로 합성한다. 연조직 변화 예측 함수는 환자 66면의 임산 결과를 바탕으로 도출하고 워핑은 얼굴 연조직 특징점 간의 해부학적 연관성을 고려하여 구현 하였다.

이면가로의 정비방안에 관한 연구

金日道,孔昌煥 慶一大學校 1996 論文集 Vol.13 No.2

The transportation planning by this time used to be made mainly on an arterial roads, and consequently minor street, which account for 70 percent of all roads, was paid no attention. Thereupon, one's function as Narrow lack street is presently deprived by illegal parking vehicles, traffic conditions are congested, and it is impossible to cope with a state of emergency. The major purpose of this study is to review the actual state and the improvement plan on minor street. The results are as follows ; 1. In the transportation planning, serious consideration should be given to minor street which account for 70 percent of all roads. Specially in the case of Daegu Cental Business District an active improvement on minor street is necessary considering parking demand and traffic flows. 2. In view of the results of analyzing parking form, illegal parking be used more than the toll parking lots. Therefore continuous and powerful guidance and for illegal parking are strongly requested. 3. It is requested to set up in good condition considering the which of Narrow lack street and the surrounding states, to plan on the field, to minimize the effect for traffic flows securing parking space. 4. To uplift one's function as minor street, it is necessary to establish off street parking space, to expand one-way traffic control system, to control parking demand and to actualize parking fees

信號交叉路의 交通特性과 左回轉 禁止에 따른 運營效果에 관한 硏究

홍익상,공창환,정우영,임채문 대구대학교 산업기술연구소 1993 産業技術硏究 Vol.12 No.-

This study analyzed the characteristics of the operation of left turns at intersections of the streets in Taegu City. The points of the study were as follows: increase of traffic capacity, decrease of delay time, and to do so this study aims at seeking a way for the most appropriate signal cycle and an effective way to operate intersections. The following are the results: 1st The arterials of Taegu City have a high rate of left turns, and yet are not divided into specific functions, which impairs the efficient use of the functions. It is required that a study be made on the way of utilizing the left turn to the maximum of the operational functions of signalized intersections. 2nd As traffic volume and left turn ratio increase, it was revealed that the optimum signal cycle and delay increased, adoption of efficient lanes was analysed to be most effective at the intersection which have a great of traffic volume and a high or rate of left turns. 3rd On the independent intersection in Taegu city, when left turn is prohibited, it may give poor approaches, but according to analyses this will bring a phenomenal decrease in the optimum signal cycle and delay.

대구시 간선가로망 구축에 의한 입체 교차로의 효율성에 관한 연구

임채문,공창환,정우영 大邱大學校 科學技術硏究所 1994 科學技術硏究 Vol.1 No.-

It is necessary to establish a link organization to device the transportion planning relieving traffic congestion. Therefore, this study has established a principal link centering around Taegu city, and reviewed the efficienay of the grade intersations and the 3-Dimensional intersations. The results of this study are as fallow; This study has established each circulation lane by Grid partition and Daiiy Traffic Volume (the 1st circulation lane; 000m, the 2nd circulation lane; 800m, the 3rd circulation lane; 1000m) The delay model of a length is t₂= exp(3.0091 +0.001242x)k (R²=0.78). The conversion of traffic volume into turning point the grade and 3-Dimensional intersection at single intersection is different by the distance between intersections. The decrease of total link delay is minute by one or two 3-Dimension on a intersection, and the 3-Dimension on the 2nd and and circulation lane is more effective than the 1st circulation lane. In the case of multi-intersections, passing time on the 3-Dimension passing throuth the urban center and the bypassing road has a little difference. For that reason, the bypassing route must be considerd instead of the 3-Dimension passing throuth the unban center. So an examination and re-settlement of the future pricipal link is necessary to organze the principal link on Taegu city using other factor.

가로특성에 따른 용량 및 속도 Model 구축

임채문,공창환,이영우,홍익상 大邱大學校 科學技術硏究所 1998 科學技術硏究 Vol.5 No.3

The purpose of this study is to develop a simulation model to estimate the capacity and the speed, which are applicable in the urban street transportation planning, for interrupted traffic flow which is influenced by the signalized intersection, and to compare the model with the existinw models.

여행속도에 따른 Q-V관계식 산정에 관한 연구

임채문,정우영,공창환,홍익상 대구대학교 과학기술연구소 1995 科學技術硏究 Vol.2 No.1

The purpose of this study is to estimate a suitable traveling speed model based on using the traffic data collected by test-vehicle traveling method and the data on road geometric and operating characteristics. The conclusions of this study are as follows. In travel speed model(Q-V), regression model (V=9.635+0.0169L - 0.00045Q - 2.1926N, R²=0.76) the important independent variables are speed is closely related with distance, traffic volume and the number of traffic lane, form the result of speed-flow regression analysis, link travel speeds are influenced by link distance, traffic volume, and the number of lanes. As expectedly by the most significant factor influencing link travel speeds. The changing of traveling speed according to section distance is appeared large. According to the result of analysis of travel speed and traffic density model(Q-K), as according the that density increases the travel speed is decreases, on the other hand travel speed increases, the density decreases. The speed equation (u=68.72e^(-k/22.6)) is derived by form the Q-K relationships founded form the study, traffic volume increases as traffic speed increase up to the critical traffic density. If traffic volume decreases when traffic density is abduce the critical traffic density. Using Q-V equation estimated by regression analysis and Q-K equation estimated by density, Traffic value test was accomplished by computer program(TRANPLAN). There were difference between too test, however, the deviation was small. On case of using program, the application extent we considered, is between 25Km/h - 60Km/h. Traffic volumes obtained from TRANPLAN are governably 10% larger than traffic volume estimated form Q-K model. However the difference of the critical traffic density bow Q-K model and TRANPLAN, are relatively small. It is desirable to reduce traffic volume by 0.7∼9% over all, speed range when TRAPLAN is applied in Q-K relationship.

신호주기에 따른 차량군 분석을 통한 속도 Model 구축

임채문,이영우,공창환,박영환 대구대학교 과학기술연구소 1999 科學技術硏究 Vol.6 No.1

The purpose of this thesis is to develop a simulation model to estimate travel speed applicable to urban street transportation planning for interrupted traffic flow, influenced by signalized intersection. This simulation model is expected to be a better and more than previous studies. The results are summarized as follow ; 1. As a result of analyzing the travel speed to the ratio of vehicle stops, the high correlation between travel speed and the ratio of vehicle stops is obtained and is more likely to have a nonlinear shape than a linear shape. 2. The algebraic equation is the most appropriate equation among the linear algebraic and exponential equations which use the ratio of vehicle stops as a variable. 3. This study suggests that the maximum travel speed is 44.73km/h when the ratio of vehicle stops is 0.01 when speed is perceived to be high, if there are no standing vehicles on the road, there is a perfect offset. There fore. there is a little traffic volume considering the maximum travel speed to be appropriate, the minimum travel speed is 16.45km/h when the ratio of vehicle stops is 1. 4. Considering many variales such as the condition of city roads and the condition of traffic signals, this study suggests the equations.

우회전 능률차로 도입에 따른 지체시간 및 효율성 분석

임채문,이영우,공창환,이주호 대구대학교 과학기술연구소 1999 科學技術硏究 Vol.6 No.2

The most important elements in planning are road width and road sectional structure which are necessary to decide by exact forecast of traffic demand, but in case of Korea, the decision still adopts unreasonable urban planning line of the past. Therefore the purpose of this research is applicate for arterials increasing of facility area and traffic effect iveness(delay and capacity) with minimum cost to make maximum effective about road transverse sectional structures.

버스안내시스템 구축을 위한 도착시간예측 알고리즘 개발

임채문,김은길,공창환,이영우 대구대학교 과학기술연구소 2001 科學技術硏究 Vol.8 No.2

This study proposed the algorithm on the estimation time of bus arrival time, using queue lengths, rules for running traffic signal and GPS position datum. The estimated values by means of proposal algorithms were done by the statistical application test. In this study, queue lengths and vehicle discharge properties based on the video photograph had been surveyed in three traffic signal intersection. The surveyed datum were analyzed that discharge headway times from one to three were about 2.5 seconds. the others were about 1.8 seconds. The datum for investigation and the calculation values by means of proposal algorithms revealed that the results based on the t-test are statistically significant.