김동윤 안영훈 2008-02 6720 https://aurora.ajou.ac.kr/handle/2018.oak/16872 학위논문(석사)--아주대학교 정보통신전문대학원 :정보통신공학과,2008. 2 제1장 서론 = 1 제2장 기존의 정지영상 압축 기법 = 3 제1절매크로블럭 분할 = 4 제2절 이산 코사인 변환 = 5 제3절 양자화 = 8 제4절 압축 부호화 = 9 제3장 행기반 이산 코사인 변환 정지영상 압축기법 = 10 제1절 행기반 이산 코사인 변환 정지영상 압축기법 = 11 제2절 압축 부호화 = 14 제3절 등급 코드 차 참조 테이블 = 15 제4장 실험결과 = 17 제1절 실험 기준 및 비교대상 = 17 제2절 압축률 = 18 제3절 시간 복잡도 비교 = 21 제5장 결론 및 향후계획 = 22 kor The Graduate School, Ajou University 아주대학교 논문은 저작권에 의해 보호받습니다. 1차원 DCT를 사용한 정지 영상 압축 Ahn, Young hoon Thesis 아주대학교 정보통신전문대학원 Ahn, Young hoon 정보통신전문대학원 정보통신공학과 2008. 2 Master http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000006720 DCT 압축 이미지 As the environmental disruption caused by the mass supply of vehicles is emerged as one of the serious problems, new cars with low pollution problems and high efficiency is needed. Because the low combustion engine is essential for the high efficiency car, diesel cars has attained attention. The low pollution regulations of the high efficiency diesel cars are classified by engine technique, fuel technique and post treatment technique. Now the study of engine technique and fuel technique is actively proceeding but it is difficult to satisfy the regulative levels only with the engine technique and fuel technique, as the regulations on exhaust fumes have escalated. Accordingly, many attempts on post treatment system have been proceeding and more technical developments are required. With regard to the post treatment system, exhaust fumes which is the major reduction target, are divided into PM and NOx. Owing to the technical development of DPF, PM is successfully reduced about 90%. In contrast with PM, the reduction technique on NOx is still on developing and the various techniques, such as LNT, LNC, SCR, etc., are presented. Among SCR methods, many advanced countries are actively proceeding the R&D of Urea-SCR, which is expected to be a leading NOx reduction technique hereafter. This study is mainly purposed to investigate the mixed features of spurting urea in SCR system, through analysing the fluid of Urea-SCR system in the exhaust part of vehicles by Fluent, commercial code. Also, this study investigates the features in case of spurting Water which has similar material property to urea, using Discrete Phase Model in Fluent and defines the factors having influences on the mixing rates of water with air, such as the numbers of wings and angle in Mixer.