Experiment of DME autothermal reforming with CGO-based catalysts

최승현(Choi, Seunghyeon),배중면(Bae, Joongmyeon) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05

DME is acronym of dimethyl ether, which is spotlighted as an ideal fuel to produce hydrogen due to its high hydrogen/carbon ratio, high energy density and easiness to carry. In this research, we calculated thermodynamic hydrogen (or syngas) yield from DME autothermal reforming and compared to other fuels. The reforming efficiency was about 80% above 700?C. Lower OCR has higher reforming efficiency but, it requires additional heat supply since the reactions are endothermic. SCR has no significant effect on the reforming efficiency. The optimized condition is 700?C, SCR 1.5, OCR 0.45 without additional heat supply. Comparing to other commercial gaseous fuels (methane and propane), DME has higher selectivity of H₂O and CO₂ than the others due to the oxygen atom in the molecule. To apply DME autothermal reforming to real system, a proper catalyst is required. Therefore, it is performed the experiment comparing various novel metal catalysts based on CGO. Experiments were performed at calculated condition. The composition of product was measured and reforming efficiency was calculated. The catalysts have similar efficiency at high temperature({sim}800?C) but, CGO-Ru has the highest efficiency at low temperature (600?C).

수소 첨가 연소를 위한 차량 탑재형 연료 개질기 개발을 위한 희박 연소가스 이용 개질 특성에 관한 연구

최승현(Seunghyeon Choi),배중면(Joongmyeon Bae),이주헌(Juheon Lee),차정화(Jeonghwa Cha) 한국신재생에너지학회 2015 한국신재생에너지학회 학술대회논문집 Vol.2015 No.11

Experiments of dimethyl ether autothermal reforming optimization

최승현(Choi, Seunghyeon),배중면(Bae, Joongmyeon),김태훈(Kim, Taehun),장덕진(Jang, Duckjin),김도연(Kim, Doyoun) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

Dimethyl ether (DME) is an attractive fuel as a hydrogen carrier for mobile PEMFC applications. However, its reforming technologies are rarely studied especially by using autothermal reforming (ATR) method. This work explored the impact of operating conditions to the performance of DME ATR. Temperature, Steam to carbon ratio(SCR), Oxygen to carbon ratio(OCR) and Gas hourly space velocity(GHSV) were considered as the operating conditions. As results, conversion efficiency was increased as the temperature increased, but saturated around 700?C. There was no significant effect of SCR on conversion efficiency, but high SCR led reactions in endothermic manner. High OCR substantially suppressed conversion efficiency, but it helped to sustain the temperature by stimulating exothermic reactions. Conversion efficiency was decreased as GHSV increased. The optimized operating conditions was suggested: 700?C, SCR of 1.5, OCR of 0.45 and GHSV below 15000/h and conversion efficiency was ~85% at the conditions.

Hydrogen and CO production in exhaust gas fuel reforming on various engine operating conditions

Seunghyeon Choi(최승현),Joongmyeon Bae(배중면) 한국신재생에너지학회 2017 한국신재생에너지학회 학술대회논문집 Vol.2017 No.5

발달장애인 그룹홈의 거주유형별 공간적 특성 분석에 관한 연구 - 경기도 장애인 그룹홈의 내부환경과 지역사회 환경을 중심으로 -

최승현 ( Choi Seunghyeon ),김정빈 ( Kim Jungbin ) 한국공간디자인학회 2023 한국공간디자인학회논문집 Vol.18 No.8

(연구배경 및 목적) 2020년 정부는 장애인을 위한 안전한 지역사회 환경의 구축과 장애인 그룹홈 시설의 유형 개발을 선언하였다. 매년 꾸준히 증가하고 있는 발달장애인에게 자립과 사회성 함양에 긍정적 영향을 미치는 것으로 알려진 장애인 그룹홈은 탈시설 정책으로 인한 공급 확대를 기대할 수 있겠지만, 장애인 그룹홈을 대상으로 도시공간 중심의 연구는 수행된 바가 없는 실정이다. (연구방법) 장애인 그룹홈이 발달장애인과 주류사회와의 사회통합을 이념으로 삼는 점을 토대로, 사회통합 실천 가능성이 높은 경기도 지역을 연구의 범위로 삼아 연구를 수행하였다. 그리고 장애인 그룹홈의 공간정보 데이터를 구축하여 시설의 공간 중심 유형화 과정을 수행하였다. 이후 거주자의 특성에 대한 이해를 중심으로 유형별 장애인 그룹홈의 공간적 특성을 분석하기 위해 대표 시설을 선정하여 현장방문을 수행하였다. 그리고 종사자 간 인터뷰, 거주자의 특성과 활동 내용을 토대로 유형별 장애인 그룹홈의 내부환경과 지역사회 환경의 공간적 특성을 도출하였다. (결과) 먼저 경기도의 장애인 그룹홈을 중심으로 기초 현황 및 공간정보 데이터를 구축한 결과, 장애인 그룹홈은 경기도의 다양한 입지를 중심으로 운영중인 것으로 확인되었다. 그 중 일반주거지역 내에는 다가구주택, 다세대주택, 아파트 유형의 그룹홈이 주요 주거유형으로 선정되었고, 비주거지역 내에는 단독 주택과 사회복지시설 유형이 주요 주거 유형으로 선정되었다. 유형별 대표 장애인 그룹홈의 내부와 지역사회 환경을 분석한 결과, 장애인 그룹홈의 입지지역은 거주자의 주간 활동의 다양성과 사회 적응훈련 시설 간 접근 방식에 영향을 미치는 것으로 확인되었다. (결론) 첫째, 단독주택과 다가구주택 및 10세대 미만의 다세대주택에 장애인 편의시설이 설치될 수 있도록 제도적 보완이 요구된다. 둘째, 아파트 유형을 제외한 일반주거지역 내 주거유형의 경우 거주자들의 안전한 지역사회 참여활동을 보장할 수 있도록 보차분리가 적용된 보행환경이 요구된다. 셋째, 비주거지역 내 장애인 그룹홈의 거주자들이 지역사회 활동에 참여하고 적응훈련을 수행할 수 있도록 접근성을 갖춘 인프라와 복지서비스의 구축이 요구된다. (Background and Purpose) In 2020, the government declared the establishment of a safe community environment and the development of various types of group-home facilities for the disabled. Group homes for the disabled―known to have a positive effect on fostering independence and sociality for the developmentally disabled―are steadily increasing every year and can be expected to expand supply due to de-facility policies. However, no research has been conducted focusing on urban spaces for disabled group homes. (Method) Based on the fact that group homes for the disabled have an ideology of social integration between the developmentally disabled and mainstream society, this study was conducted in the area of Gyeonggi-do, which is highly likely to practice social integration. By constructing spatial data on group homes for the disabled, a spatially centered categorization process of facilities was performed. Subsequently, to analyze the spatial characteristics of group homes for the disabled by type, focusing on understanding the characteristics of residents, representative facilities were selected and field visits were conducted. Furthermore, based on interviews with workers and the characteristics and activities of residents, the spatial characteristics of the internal and community environments of group homes for the disabled by type were derived. (Results) First, by constructing basic status and spatial information data centered on the group homes for the disabled in Gyeonggi-do, it was confirmed that these group homes operate in various locations in Gyeonggi-do. Among them, group homes with multifamily housing and apartment types were selected as the main types of housing in general residential areas, whereas single-family housing and social welfare facilities were selected as the main types of housing in non-residential areas. By analyzing the internal and community environment of the group homes for the disabled by type, it was confirmed that the location of these group homes affected the diversity of residents’ weekly activities and the approach between social adaptation training facilities. (Conclusion) First, institutional supplementation is required so that convenience facilities for the disabled can be installed in detached, multifamily, and multifamily houses with fewer than 10 households. Second, in the case of housing types in general residential areas, excluding apartments, a walking environment with pedestrian separation is required to ensure safe community participation activities of residents. Third, it is necessary to establish accessible infrastructure and welfare services so that residents of group homes for the disabled in nonresidential areas can participate in community activities and conduct adaptation training.

사물인터넷 환경에서 CoAP을 이용한 디바이스 해킹시나리오 및 대응방안

최승현 ( Choi Seunghyeon ),서초롱 ( Seo Chorong ),이근호 ( Keun-ho Lee ),전유부 ( You-boo Jeon ) 한국정보처리학회 2016 한국정보처리학회 학술대회논문집 Vol.23 No.1

최근 정보통신기술의 눈부신 발전으로 사람-사람, 사람-사물, 사물-사물 각각을 연결하여 최대한의 시너지를 발휘하려는 움직임이 활발해지고 있다. 즉 일상생활에서 사용되는 자동차, 가전제품, 드론 등의 제품도 연결되어 통신하는 사물인터넷 시대가 도래 하고 있다. 머지않아 모든 기기가 연결되는 시대가 오면 물리적 보안 보다 논리적 보안이 중요해 질 것이다. 또한 사물인터넷 해킹은 정보보호라는 단위를 넘어 사람의 생명과 직결되는 해킹 피해가 발생할 위험이 있다.

CNN을 이용한 재난 예경보 시스템

최승현(SeungHyeon Choi),김도현(DoHyeon Kim),김형헌(HyungHeon Kim),김윤(Yoon Kim) 한국컴퓨터정보학회 2019 韓國컴퓨터情報學會論文誌 Vol.24 No.2

In this paper, we propose an intelligent CCTV technology which is applied to a recent attracted attention real-time object detection technology in a disaster alarm system. Natural disasters are rapidly increasing due to climate change (global warming). Various disaster alarm systems have been developed and operated to solve this problem. In this paper, we detect object through Neuron Network algorithm and test the difference from existing SVM classifier. Experimental results show that the proposed algorithm overcomes the limitations of existing object detection techniques and achieves higher detection performance by about 15%.

가솔린 엔진의 수소 첨가 연소를 위한 차량 탑재형 배기가스 이용 연료 개질 특성에 대한 연구

최승현(Seunghyeon Choi),배중면(Joongmyeon Bae),이주헌(Juheon Lee),차정화(Jeonghwa Cha) 한국자동차공학회 2015 한국자동차공학회 부문종합 학술대회 Vol.2015 No.5

In current days, fuel economy of automobile become major concerns for not only consumers but also automobile products. The addition of hydrogen in lean burn combustion is one of the way to increase fuel economy. By the way, for supply hydrogen to automobile engine, we need to hydrogen source. On-board fuel reforming can be a solution for hydrogen supply in automobile system. To produce hydrogen with fuel reformer, we need oxidizer. Current fuel reformer need to additional water tank and air compressor. So we use exhaust gas, due to there are enough steam and oxygen in engine exhaust gas and we have experience of exhaust gas reuse, similar to EGR system. In this work, we found the possibility of fuel reforming with using exhaust gas by calculation of thermodynamic equilibrium. After calculation of fuel reforming we test our fuel reforming system with iso-octane with monolith coated CGO-Pt catalyst. Fuel was fully converted by hydrogen and synthetic gas during changing exhaust gas ratio, temperature, composition of exhaust gas and GHSV of reactant. Maximum fuel conversion efficiency was 78% at certain operating condition.

In-Storage Processing을 위한 Single-board Computer 기반의 Mesos 분산처리시스템

김주환(JooHwan Kim),조주영(Juyoung Jo),최승현(SeungHyeon Choi),이재환(Jaehwan Lee) 한국정보과학회 2016 한국정보과학회 학술발표논문집 Vol.2016 No.6