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한국형 우주비행기의 기준 항력 추종 기반 재진입 유도 기법
윤다인(Da-In Yoon),김영원(Young-Won Kim),이창훈(Chang-Hun Lee),최한림(Han-Lim Choi),유혁(Hyeok Ryu) 한국항공우주학회 2021 韓國航空宇宙學會誌 Vol.49 No.8
본 논문에서는 한국형 우주비행기(KSP)에 대한 새로운 재진입 유도를 제안하고자 한다. 제안된 방법은 우주 왕복선 유도 개념과 유사하게 다양한 비행경로 제약조건과 경계조건을 만족시키는 기준 항력 프로파일을 미리 결정하고, 결정된 기준 항력 프로파일을 추종하는 방식으로 유도명령이 구현된다. 이를 위해 본 연구에서는 항력 동역학을 조사하였으며, 그 결과 항력과 비행경로각의 동역학적 응답 특성이 상당히 다르다는 사실이 밝혀졌다. 이 사실을 바탕으로 제안한 유도명령은 시간분리 기법과 궤환선형화 방법을 사용하여 결정된다. 제안한 유도기법의 주요 특징은 간단한 구조와 명확한 작동 메커니즘에 있다. 따라서 제안된 방법은 기존 방법에 비해 구현이 간단하다. 본 논문에서는 제안된 방법의 성능을 조사하기 위해 수치 시뮬레이션을 수행한다. This paper aims to propose new reentry guidance for Korean Space plane (KSP). Similar to the Space Shuttle guidance concept, a reference drag profile is first determined to satisfy several flight path constraints and boundary conditions, and the proposed guidance commands are realized in a way to track the predetermined reference drag profile. To this end, the drag dynamics is examined. The investigation uncovers that the dynamics characteristics of the drag and the flight path angle are considerably different. Based on this fact, the proposed guidance commands are determined using the time-scale separation technique and the feedback linearization methodology. The key feature of the proposed guidance lies in its simple structure and a clear working mechanism. Therefore, the proposed method is simple to implement compared to existing methods. Numerical simulations are performed to investigate the performance of the proposed method.
순산소와 Vortex Aerator를 이용한 도심하천의 수질 및 악취 관리
윤다인(Yoon, Dain),최미정(Choi, Mijeong),박성혁(Park, Sunghyuk) 대한토목학회 2021 대한토목학회논문집 Vol.41 No.5
와류에 의해 물과 산소의 충돌을 반복적으로 일으켜 산소를 용존시키는 Multistage Vortex Aerator를 하천 정화에 적용하였다. 본 연구의 대상 현장인 괴정천은 부산시 사하구 도심을 흘러 낙동강 하구로 연결되는데, 우천 시에는 비점 오염물질이 유입되고 평시에도 하수 슬러지가 일부 유입되어 퇴적을 반복함에 따라 하천수의 용존산소 농도가 혐기성 상태에 가까웠다. 산소농도가 최소 0.1 ppm인 하천수를 흡입하여 22 ppm 이상으로 산소를 용존시켜 분당 1 m³을 순환시켰을 때, 하천에 나타나는 수질과 악취 변화를 2개월간 모니터링하였다. 운영 결과, 용존산소가 하천 전체적으로 약간 나쁨(4)~나쁨(5)에서, 좋음(1b)~보통(3) 등급으로 개선되었고, 총인 농도는 평균 76 % 감소되었다. 복합악취는, 하천 전체가 혐기화된 측정일에 최대 84.5 % 저감을 관찰할 수 있었다. The target site, Goejeongcheon flows through downtown of Saha-gu, Busan and it connects to the Nakdong-gang estuary. But non-point pollutants and sewage sludge are partially flowing into the stream and deposited. As a result, dissolved oxygen concentrations of the stream were observed close to the anaerobic condition. Multistage Vortex Aerator was applied for restoring this urban stream. It dissolves oxygen by repeatedly causing collisions between water and oxygen by vortex flow. The changes in water quality and odor were monitored for 2 months while circulating 1 ㎥/min of water with 22 ppm dissolved oxygen. As a result of the operation, the dissolved oxygen was improved from slightly Bad (4)~Bad (5) to Good (1b)~Normal (3) grade, and the total phosphorus concentration was decreased by 76 % on average. In the case of complex odor, a maximum reduction of 84.5 % was observed on the day the entire river was anaerobic. Through this study, we evaluated the feasibility of applying pure oxygen and Vortex Aerator for the the stream restoration. It is expected that the results of this study can be used for full-scale design.
윤다래,이지숙,노현인,이서라,류재환,Yoon, Da-Rae,Lee, Jee-Sook,Noh, Hyun-In,Yi, Seo-Ra,Ryu, Jae-Hwan 대한한방내과학회 2012 大韓韓方內科學會誌 Vol.33 No.2
Objectives : This study was aimed to provide the basic characteristic of patients who visited an Oriental medical hospital emergency room. Methods : We performed a retrospective study on 1,119 patients who visited Kyunghee University Oriental Medical Hospital Emergency Room from June 1, 2011 to March 31, 2012. Results and Conclusions : 1. In distribution of sex, the rate of males was 44.1%, and that of females was 55.9%. The male to female ratio was thus 1:1.26. The patients' average age was 54.64 and the 6th decade of life was the peak age group. 2. Most of the patients visited the Oriental medical hospital emergency room between 11:00 and 23:00. 3. In distribution by days of the week, the most common was Sundays (24.5%), followed by Mondays (16.7%). 4. In the month distribution, the most was December (12.4%), followed by November (10.0%). 5. The patients were grouped as follows: neurological diseases 58.9%, musculoskeletal disease 27.5%, internal medical disease 10.4%, and others 3.2%. 6. Admission rate of patients being treated was 38.8%, and the admission to the intensive care unit (ICU) was 4.5%. of total visiting patients.
윤다일 ( Dail Youn ),김민혜 ( Min-hye Kim ),고석웅 ( Seok Woong Koh ),김정원 ( Jung Won Kim ),윤상은 ( Sang Eun Yoon ),전현경 ( Hyeon Kyeong Jeon ),조영주 ( Young-joo Cho ) 대한천식알레르기학회(구 대한알레르기학회) 2016 Allergy Asthma & Respiratory Disease Vol.4 No.3
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse reactions to drugs, which carry significant morbidities and mortalities. Although SJS and TEN can be treated by corticosteroids or intravenous immunoglobulin, they may be induced by steroids. We experienced a 36-year-old man who developed whole body erythromatous maculopapular rashes and multiple bullae after ingestion of deflazacort. After avoidance of deflazacort and use of dexamethasone, skin lesions resorbed. We reported a case of TEN diagnosed by characteristic clinical findings with a brief review of the literature. (Allergy Asthma Respir Dis 2016;4:221-224)