대형 디젤엔진에서의 Low Pressure Loop EGR 적용을 위한 기초연구

하창현(Changhyun Ha),이승재(Seungjae Lee),이교승(Kyoseung Lee),김상호(Sangho Kim),전광민(Kwangmin Chun) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

It is known that low pressure loop EGR is one of the best way to improve DeNOx efficiency and EGR distribution. This study is about applying low pressure loop EGR to an engine that was not equipper with EGR system. The goals of this study are to achieve 30% of maximum EGR rate and well distribution of EGR flow to meet more stringent emission standard. To validate the simulation model, experimental data of baseline engine without EGR system and simulation results using I-D WAVE code and 3-D VECTIS code are compared for ESC-13 mode. <br/> The result is satisfactory in ±5% error bound. For applying low pressure loop EGR, optimum EGR pipe diameter was 30mm which was about 30% of intake pipe diameter. In case of applying low pressure loop EGR system, DeNOx efficiency was about 60~80% and cylinder-to-cylinder EGR rate deviation was within 5%. However, HC emission was increased to 55%. <br/>

도심환경 인식과 도시재생방향 설정의 인과관계 분석

하창현(Ha, Chang-Hyoun),김영(Kim, Yeong),김기홍(Kim, Ki-Hong) 한국지역개발학회 2009 韓國地域開發學會誌 Vol.21 No.3

The aim of this study is to analyze between the recognition of urban center environment and the policy making of urban regeneration in local cities of Masan and Jinju. For this study, we used a survey the questionnaire to assess the urban centre environment, satisfaction in the use of facilities and urban improvement of the urban environment. The questionnaire data was analyzed using descriptive statistics, confirmation factor analysis and structure equation model (SEM) for the relation between cause and effect. The results of the study are as follows; First, the image and amenity factors in the city center environmental assessment indicated insufficiency, and the satisfaction of the culture and the leisure in the urban facility use indicated the most complains. Second, the culture and image factors in environmental improvement indicated the highest importance because the existing city centre lacked in comfortable space. Third, the analytical model of the SEM indicated the relation of inter-latent variable between cause and effect. Masan city signified following in the hypothesis: 1) environmental assessment → satisfaction, 4) use satisfactory → improvement program and 6) improvement program → regeneration goal. The results of Jinju city in the hypothesis are 1) environmental assessment → satisfaction and 6) improvement program → regeneration goal.

e-러닝 환경에서 상호 인터페이스 구현

하창현(Ha, Chang-Hyun) 한국전시산업융합연구원 2006 한국과학예술융합학회 Vol.2 No.-

기능적ㆍ공간적 측면에서의 경남지역 공간계획권역의 설정

하창현(Ha Chang-Hyoun) 한국도시행정학회 2007 도시 행정 학보 Vol.20 No.1

This study aims to analyze the spatial structure in Gyeongnam province since the 1970s for the establishment of a new regional development strategy for Gyeongnam province, and to utilize analysis results as basic data for further regional development. This study also aims to propose a regional development policy aimed at installing the proper spatial structure by dividing the province into regions. Spatial analysis results for Gyeongnam province are as follows: First, with respect to the spatial change in population, the population in the counties was relatively high in the 1970s but population in the rural areas decreased sharply due to urbanization and industrialization. The population distribution pattern showed gradual concentration in the Busan, Ulsan, and Masan-Changwon-Jinhae regions, and recently exhibited a sharp increase in population in Gimhae and Yangsan cities owing to the regional expansion of the Busan metropolitan city. The Gini coefficient increased sharply from 0.2070 (1970) to 0.4704 (1990), and to 0.5547 (2005), showing severe population imbalance in the Gyeongnam province. Second, with respect to industrial distribution, most of the industrial facilities were concentrated in the cities, and regional imbalance was very severe by the concentrated distribution in the eastern part of the province. Especially, most of the manufacturing facilities in Gyeongnam province were concentrated in the east-south shore region of Geojae - Masan-Changwon - Gimhae - Busan - Yangsan - Ulsan. Concentration of the manufacturing facilities has become more severe since 1998. Third, Gyeongnam province was classified into five planning regions namely, Jinju, Masan-Changwon-Jinhae, Busan-Ulsan, Geojae-Tongyecng, and Daegu (Geochang) based on population size, population migration, and industrial distribution pattern. Most of the population and industrial facilities were concentrated in Masan- Changwon-Jinhae, and the Busan-Ulsan regions, manifesting severe regional imbalance.

지역개발정책 수립을 위한 기초연구로서 소득불균형의 진단과 완화방안 연구

하창현(Ha Chang-Hyoun),김지연(Kim Ji-Yon) 한국도시행정학회 2008 도시 행정 학보 Vol.21 No.2

The purpose of this paper is to analyze income inequality and mitigation as basis study for policy making of regional development in Gyeongnam Province. For this study, we used the Social Index Survey Data(SISD) from the National Statistics Organization(NSO). Income data were classified into nine types and according to metro-regional unit. In this study, various inequality measurement indices were used such as the Gini coefficient and ER measure. The results of this study are the following:First, income inequality was not serious for the recent 5 years, but ER measure was relatively high. The regions whose income inequality has further increased were Daegu and Chungbuk, whereas that of Gyeongnam was average. Second, income inequality did not increase more than that in other metro-regions because of the region's industrial manufacturing infrastructure, but total income level was low in Gyeongnam. Third, the establishment of regional development policy must be considered in two parts for Gyeongnam: high income creation by shifting industrial infrastructure toward high technology and variety, and the extension of the social welfare system to alleviate poverty.

부산 대도시권의 공간재편 과정의 이해와 특성 분석

하창현(Ha, Chang-hyoun),김기홍(Kim, Ki-hong),남진(Nam, Jin) 한국주거환경학회 2015 주거환경(한국주거환경학회논문집) Vol.13 No.1

This study aims to analyzed the change of the population size, industry, intra-urban migration in Busan metropolitan area between 2000 and 2010. This study has focused on the spatial redistribution process and pattern for the urban management and policy. The major findings of the study are as follows. First, the ratio of population of the urban city centre to the sub-urban has continuously decreased, especially those Jeonggwan-myun, Mulgeum-eup, Jangyu-myun of new town area greatly increased. Second, the ratio of industry annual average is 5% increase, and the ratio of the manufacturing industry and consumer service is never changed. As well consumer service and consumer service are area-based service industry increased 6% annual average. It is shown a particular population distribution tends to decrease in a particular deindustrialization on obstruction factor where affects in urban growth. Third, population migration trend for different spatial distribution corresponds to regional characteristics differently. Since 2010, the ratio of population migration increased and especially, such an increasing phenomenon is more prominent in sub-urban and rural areas than urban areas. Finally, Netminer 3.0 analysis the change of the centrism trend for different spatial redistribution corresponds to regional characteristics differently. So, this study concludes with some policy implications a need of further study.

대상의 사회경제적 지위가 대상이 겪는 고통을 추정하는 데에 미치는 영향: 지각된 피부색의 매개효과에서 ‘검을수록 단단하다’는 색 고정관념의 조절효과

하창현(Chang Hyun Ha),박상희(Sang Hee Park) 충남대학교 사회과학연구소 2023 사회과학연구 Vol.34 No.1

This study aimed to determine whether there are differences in the pain perception of targets depending on their socioeconomic status (SES). Furthermore, we explored whether targets with a lower SES were expected to have darker skin tone, which would ultimately lead to perceiving the target as feeling less pain. Additionally, we examined whether this bias would be more prominent for participants with a stronger ‘darker is stronger’ color stereotype. Our research hypotheses, measurement tools, analysis methods, and sample size calculation were pre-registered. Participants were assigned to one of four conditions (SES: high vs. low ✕ target gender: female vs. male). They read vignettes about targets, and answered questions about target SES (manipulation check), perceived skin tone, emotional/physical pain, color stereotype, and an attention check item. We found a statistically significant difference only in emotional pain, but the direction was opposite to our expectations. Participants perceived low (vs. high) SES targets’ skin tone as darker (vs. lighter), which was associated with a higher estimation of targets’ emotional pain. In other words, the relationship between SES and pain perception was mediated by the perceived skin tone; however, the direction of the mediation effect was opposite to our prediction. We also tested whether the mediation effect was moderated by color stereotype. In participants with a moderate or strong color stereotype, the darker the targets’ skin was perceived, the more the targets were estimated to feel emotional pain. The result was opposite to our prediction. This study indicates that the existence of a bias in estimating emotional pain of targets depending on high or low SES.

스포츠 동호회를 위한 안드로이드 스포츠 중계 시스템의 설계와 구현

하창현(Chang-Hyun Ha),박준만(Jun-Man Park),강지원(Ji-Won Kang),좌정우(Jeong-Woo Jwa) 한국통신학회 2018 한국통신학회 학술대회논문집 Vol.2018 No.6

저압라인 EGR을 적용한 대형 디젤엔진의 EURO-4 규제 대응 전략에 관한 수치적 연구

하창현(Changhyun Ha),이승재(Seungjae Lee),이교승(Kyoseung Lee),전광민(Kwangmin Chun) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.1

고분자 공중합체와 알루미늄 양극 산화막 템플레이트를 이용한 나노점 배열 형성

박성찬,배창현,박승민,하정숙,Park Sung-Chan,Bae Chang-Hyun,Park Seung-Min,Ha Joeng-Sook 한국진공학회 2006 Applied Science and Convergence Technology Vol.15 No.4

자발적인 미세상 분리에 의해 실린더형의 규칙적인 배열을 형성하는 고분자 공중합체와 알루미늄의 양극산화에 의해 실린더형 기공 배열이 형성되는 알루미나 템플레이트를 이용하여 다양한 물질의 나노점 배열을 형성하였다. 펄스형 레이저 기상 증착법을 이용하여 은, 니켈, 산화아연, 실리콘, 코발트 / 백금 나노점 배열을 얻었는데, 나노점의 크기와 배열은 템플레이트의 기공 크기와 배열을 보여주었다. 이러한 템플레이트 기법을 이용하면 나노점의 밀도는 고 분자 공중합체와 알루미나의 경우 각각 $6{\times}10^{11}/cm^2$ 와 $1{\times}10^{10}/cm^2$ 이다. 이중 에르븀이 도핑된 실리콘 나노점과 ZnO 나노점 배열은 PL 측정을 통하여 물질의 광학성질에 관해 알아보았다. 에르븀이 도핑된 실리콘 나노점 배열은 $1.54{\mu}m$에서 강한 빛을 내며 ZnO 나노점 배열은 380 nm 에서 강한 PL 세기를 나타낸다. We have fabricated nanodot arrays by using phase separated (PS- b- PMMA) diblock copolymer film and anodic aluminum oxide (AAO) membrane as templates with hexagonal arrays of cylindrical microdomains perpendicular to the substrate. Pulsed laser deposition technique was used to deposit various kinds of materials including Ag, Ni, ZnO, Si:Er, and Co/Pt onto Si substrates. The size and separation of nanodots correspond to those of the templates used, The density of nanodots was estimated to be $6{\times}10^{11}/cm^2$ and $1{\times}10^{10}/cm^2$ when the diblock copolymer and AAO were used, respectively. In particular, the optical properties of ZnO and Si: Er nanodot arrays were investigated and the strong photoluminescence at 380 nm and $1.54{\mu}m$ was observed from ZnO and Si:Er nanodot arrays, respectively.