http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
3차원 풍동시험을 위한 새로운 벽면적응방식의 수치적 검증
장병희(B.H. Chang),성봉주(B. Sung),장근식(K.S. Chang) 한국전산유체공학회 1997 한국전산유체공학회 학술대회논문집 Vol.1997 No.-
The conventional adaptation methods of the 2D Adaptive Wall Test Section for the 3D testing have three defects which are the dependency on the target line, the pressure hole distribution, and the influence coefficients. In the previous study, a new adaptation algorithm of 2D Adaptive Wall Test Section for 3D testing has been proposed and evaluated through numerical tests. In the new algorithm, the adapted wall shape is obtained by an optimum procedure in which influence coefficients are unnecessary. The wall interference is taken as the summation of area weighted pressure difference, so the target line is unnecessary, also. In this study, the last defect, the dependency on the pressure hole distribution, is examined through numerical tests. The new adaptation method is proved as insensitive to the pressure hole distribution. This means that it can be applied to real wind tunnel tests in which the conventional adaptation method is failed.
비정상유동 실험시의 비정상 적응벽면 모델의 수치적 연구
장병희(Byeong-Hee Chang),장근식(Keun-Shik Chang) 한국전산유체공학회 1995 한국전산유체공학회 학술대회논문집 Vol.1995 No.-
The adaptive wall test section has distinct advantage over the other devices for reduction of wall interference in the wind tunnel testing. For two-dimensional steady flows the wall adaption strategy has been well established and, in some extent, has been effectively applied to three-dimensional steady flows. For unsteady testing, the wall adaptation is conceptually possible but has never been realized in the wind tunnel experiment. In this study, relatively simple adaptive wall models have been proposed and evaluated through numerical tests. The effect of Mach number, frequency, and amplitude of pitching oscillation on the wall interference reduction has been also studied.
장병희(B. H. Chang),장근식(K. S. Chang) 한국전산유체공학회 1996 한국전산유체공학회지 Vol.1 No.1
Wall interference is one of the major obstacles to increase the model size and data accuracy. There have been many treatments for wall interference including interference correction and adaptive wall test section. Recently, two-flexible-walled adaptive wall test section is concluded adequate for three-dimensional test. But proper location of target line and pressure holes are critical to its success. In this study, a new adaptive algorithm which dispenses target line and dependency of pressure hole distribution is suggested. The wind tunnel and free air tests are simulated by the numerical computation of Euler equations. The optimum wall shape is achieved by two variable optimization which is composed of two base streamlines. The wall interference is reduced well in the optimized result which is not sensitive to the base streamlines.
신문, TV 뉴스, 인터넷 뉴스 간 이용자 충족 적소분석
장병희(Byeng-Hee Chang) SBS 2010 미디어경제와 문화 Vol.8 No.2
이 연구는 인터넷을 통한 뉴스 이용이 일반화되면서 격화된 뉴스미디어 간 경쟁관계를 충족 적소분석을 통해 살펴보고자 하였다. 500명을 대상으로 온라인 설문조사를 통해 데이터를 수집하였으며, 적소이론의 대표적인 개념인 적소폭, 적소중복, 경쟁우위를 활용하여 뉴스미디어로서 종이신문, TV, 인터넷 간 경쟁관계를 분석하였다. 기존 연구와 동일하게 뉴스미디어 이용의 충족은 인지적, 효율성/감시, 충족기회, 적극성 등으로 구분할 수 있었다. 적소폭 분석 결과, 인터넷이 종이신문과 TV에 비해 상대적으로 넓은 적소폭을 가지고 있음이 발견되었다. 적소중복 분석을 통해 종이신문과 TV가 뉴스미디어로서 경쟁관계가 가장 강한 것으로 나타났다. 인터넷과의 경쟁에 있어서는 종이신문에 비해 TV가 상대적으로 강한 경쟁관계를 가진 것으로 발견되었다. 경쟁우위 분석 결과, 대부분의 충족 차원에서 인터넷, TV, 종이신문 순으로 경쟁력을 가진 것으로 나타났다. 위계적 회귀분석을 통해 이러한 충족 차원들은 집합적으로 각 미디어의 이용량 증대에 유의미한 영향력을 미치는 것이 확인되었다. 단계선택 회귀분석을 통해 충족 차원들 중 인지적 차원이 미디어 이용에 있어 가장 중요한 차원이라는 점이 밝혀졌다. This study tries to analyze the competing relationships among news media. This study collected data through an online survey of 500 general sample and compared newspaper, TV, and the Internet by the main concepts of niche theory such as niche breadth, niche overlap, and competitive superiority. Similar to a previous study, this study found four types of news usage gratifications such as cognitive, efficiency/ surveillance, gratifications opportunities, and proactivity dimensions. The result of niche breadth analysis shows that the Internet has the wider niche breadth compared to newspaper and TV. Niche overlap analysis reveals that the competition between newspaper and TV is the strongest. Also, TV has the closer competition relationship with the Internet than newspaper does. The analysis of competitive superiority shows that the Internet has the highest competitive superiority followed by TV and newspaper. Hierarchical regression analysis confirms that the collective inclusion of gratifications dimensions can significantly increase the usages of the news media. Stepwise regression analysis shows that cognitive dimension is the most important among the gratifications dimensions.