EGR Cooler 내부 형상에 따른 Fouling이 냉각 성능에 미치는 영향

남연우(Younwoo Nam),오광철(KwangChul Oh),이천환(Chunhwan Lee),이춘범(Chunbeom Lee),이원남(Wonnam Lee) 한국자동차공학회 2011 한국 자동차공학회논문집 Vol.19 No.1

오프라인 리테일 판매량 예측을 위한 SNS데이터의 활용 가능성 연구

송연우(Younwoo Song),이석명(Suk Myung Lee),강무훈(Moohoon Kang),이윤근(Yun-Geun Lee) 한국정보과학회 2022 한국정보과학회 학술발표논문집 Vol.2022 No.12

영아기 자녀를 둔 어머니들의 부모역할적응 프로그램에 관한 인식

이연우 ( Lee Younwoo ),성영화 ( Sung Younghwa ) 한국유아교육학회 2017 유아교육연구 Vol.37 No.4

본 연구는 영아기 자녀를 어린이집에 보내는 어머니들의 부모역할적응 프로그램에 대한 인식을 살펴보고 어머니들의 취업유무에 따라서 차이가 나타나는지 조사하였다. 이를 위한 연구 대상은 S특별시, B광역시, A시에 소재한 어린이집에 재원 중인 만 2세 이하의 영아기 자녀를 둔 어머니 186명이었다. 수집된 자료는 카이검증 및 t-test를 통해 분석하였다. 연구결과 첫째, 어머니들은 취업유무에 따른 유의미한 차이 없이, 부모역할적응 프로그램의 필요성에 대해 높게 인식하였다. 프로그램의 목적에 관해 어머니들은 어린이집 및 보육교직원에 대한 신뢰감을 형성하거나 긍정적인 태도 증진에 두어야 한다고 응답하였다. 둘째, 부모역할적응 프로그램 내용에 관한 어머니들의 인식에서는 영아의 어린이집 적응 절차와 협력 사항 및 놀이를 통한 영아와의 상호작용에서 높은 평균을 보였다. 특히, 취업을 한 어머니들은 보육교사의 이해에 대한 내용에서 가장 높은 평균을 보인 반면, 취업을 하지 않은 어머니들은 영아의 어린이집 적응절차와 협력사항에서 가장 높은 평균을 나타냈다. 셋째, 어머니들은 프로그램을 실시하는 방법으로 토론을 활용하고 1학기에 1~2회 교육을 제공하며 소집단 형태의 집합교육과 체크리스트를 활용한 프로그램 평가가 이루어져야 한다는 응답이 높게 나타났다. 이러한 결과를 토대로 향후 부모들의 특성 및 선호를 고려한 부모역할적응 프로그램의 개발 및 적용에 대한 시사점을 제언하였다. The purpose of this study was to investigate perceptions of mothers about parent role adjustment program in daycare center by focusing on the differences in perceptions of working mothers. To fulfill the purpose, questionnaires were obtained from 186 mothers sending their infants to daycare centers located in S, B, and A cities. The obtained data were analyzed by using chi-square and t-test. The results of this study were as follows. First, mothers perceived that the parent role adjustment program was necessary to implement regardless of their job existence. Mothers also perceived that the purpose of this program needs to focus on promoting positive attitude and building reliable relationship with teachers and staffs in daycare center. Second, regarding to the contents of the program, mothers indicated the importance of providing the lessons related to the interactive play with infants and the procedure to infants` adjustment to daycare center. Third, mothers preferred small-group type`s training and 1-2 sessions per semester to implement the program. Regarding to the program training time and program assessment, mothers with job preferred the morning time in weekends compared to the mother without job. Based on these results, discussions and suggestions for further study were provided in terms of developing efficient program for parent role adjustment and its practical application to daycare center setting.

EGR cooler Fouling이 냉각 성능에 미치는 영향에 관한 연구

남연우(Younwoo Nam),오광철(Kwangchul Oh),김덕진(Dukjin Kim),김종훈(Jonghun Kim),이천환(Chunhwan Lee),이춘범(Chunbeom Lee) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

Understanding the exhaust gas recirculation (EGR) cooler fouling in diesel engine is important factor in the durability characteristic of the EGR system. We develope the test rig and PM feeder using carbon black to examine the effect of fouling on EGR cooler devices those were consisted of flat and spiral type tube. The EGR cooler fouling process is a complex interaction involving heat exchanger shape, boundary condition, constitutes, chemistry and operating mode. As the soot deposited to EGR cooler, these formed a thin deposit layer that was less heat exchange than the fresh status of tube enclosing the exhaust gas, resulting in lower heat exchange effectiveness in both type coolers. But these deposits caused different results in pressure drop, it is increased in flat type, but decreased in spiral type of EGR cooler. A cause was estimated from a change of the flow structure and a decrease of contac area as the EGR cooler fouling.

언어 지연 아동을 위한 부모-실행 언어 중재에 관한 연구 분석

이연우 ( Younwoo Lee ) 한국특수교육문제연구소 2014 특수교육저널 : 이론과 실천 Vol.15 No.2

본 연구는 부모-실행 언어 중재가 언어 지연 유아의 의사소통과 표현 언어 향상에 미치는 정도를 1990년 이후 실행된 연구들의 분석을 통해 알아봄으로서 효율적인 부모-실행 언어중재 방법에 대해 제안하고 있다. 부모 훈련과 언어 중재에 관한 구체적인 특성들이 비교 분석되었으며, 중재 전략의 효과성에 영향을 주는 중요한 특성들을 조사하였다. 총 11개의 연구가 선정되었으며, 각 논문별로 대상자의 특성, 부모 훈련과 언어중재의 주요 특성, 연구 설계와 결과, 주요 결과와 중재 충실도와의관계 등을 비교 분석하였다. 본 연구 분석을 통해, 부모실행 언어 중재는 아동과 부모의 언어 전략 사용의 정도에서 차이를 나타내었으며, 부모실행 언어 중재 전략 중아동의 반응을 기다리고, 여러 종류의 질문을 던지거나, 충분한 반응시간을 주는 것과같은 전략들은 다른 전략들보다 아동들의 표현 언어 향상에 도움이 되었음을 기술하였다. 언어 중재에 관한 충실도에 대해 구체적인 정보를 기술한 연구는 11개 중 6개로서, 부모의 언어 전략사용에 대한 빈도수를 기록하거나, 실행 체크리스트를 사용하였음을 보고하였다. 특히, 언어 중재에 대한 충실도를 잘 수행한 연구에서, 대상아동들의 표현 언어가 다른 연구보다 더 많이 향상되었음을 기술하였다. 본 연구는 또한 부모 훈련과 언어 중재에 있어서 부모의 전략적인 언어 기술의 사용과 아동의 의사소통 능력 향상을 실증적으로 뒷받침하기 위해, 보다 효과적인 중재 충실도 실행의 필요성과 중요성에 대한 시사점을 제공한다. The purpose of this study is to analyze studies that examined the effectiveness of parent-implemented language interventions to improve expressive language and communication skills for young children with disabilities. By describing and comparing the specific characteristics of parent training and language intervention across studies and the findings obtained, this study examines the critical features that may influence the effectiveness of these strategies. A total of 11 studies were identified that met the criteria established for inclusion in this review and each of these studies were analyzed in terms of the characteristics of participants, the features of parentimplemented language strategies, parent training, research designs, and major findings. Of the 11 studies, 6 studies conducted Dialogic Reading (DR) interventions and 5 studies implemented Milieu Language Teaching (MLT) interventions. Results of this analysis indicated that parent-implemented language interventions generally increased parent’s use of effective language strategies and the expressive language skills for children with language delays. Also, results reported that some language strategies such as expanding, repeating, waiting for responses were used more frequently than other strategies. In the procedure of teaching language strategies, results indicated that individual training sessions were more effective than group training sessions. Analysis results also showed that strong fidelity of implementation was conducted in studies that used fidelity checklist or encoded the frequency of the parent use of language strategies during the language intervention. In the studies that used strong types of fidelity implementation, children improved their expressive language outcomes. Limitations and implications are also discussed in terms of examining fidelity of implementation to determine the effect of the parent-implemented language interventions on children’s language outcomes.

매연입자 발생장치를 이용한 디젤 배기가스 내 매연 및 유기성 용해물질(SOF) 모사

남연우(Younwoo Nam),오광철(Kwangchul Oh),이천환(Chunhwan Lee),이춘범(Chunbeom Lee) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

치과용 초음파 골수술기 설계 및 평가

이주희,오정민,홍연우,김세기,백종후,이영진,이정배,이승대,Lee, Joo-Hee,Oh, Jung-Min,Hong, Younwoo,Kim, Seiki,Paik, Jonghoo,Lee, Young-Jin,Lee, Jeong-Bae,Lee, Seung-Dae 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.12

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

함산소 연료 및 산화제 첨가에 따른 에틸렌화염의 매연 생성 특성 변화

남연우(Younwoo Nam),이원남(Wonnam Lee) 한국연소학회 2008 KOSCOSYMPOSIUM논문집 Vol.- No.-

The soot formation characteristics of ethylene diffusion flames have been experimentally investigated in order to understand the synergistic effect of oxygenated fuel. The role of methyl radical and/or oxygenated species assisted pyrolysis on the soot formation process could explain the increase of soot volume fraction with DME or ethanol mixed to ethylene. The addition of N₂O to ethylene fuel only enhances the soot formation process that is similar to the pure oxygen addition case. However, the addition of oxygenated species might reduce the soot amount in oxidation region, and therefore, it might suppress the overall soot formation process in turbulent flames.

내부로 공급되는 공기 유량에 따른 에틸렌 확산화염의 매연 방출 현상

남연우(Younwoo Nam),문두성(Dusung Moon),이원남(Wonnam Lee) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41

The characteristics of soot formation with air addition have been studied experimentally using a concentric co-flow diffusion burner, which provides the stratified air mixture through an inner nozzle. Integrated soot volume fraction, temperature and scattering images of diffusion flames were measured using a laser light extinction method, two-color pyrometry and 2-D laser light scattering technique, respectively. An ethylene diffusion flame started to emit soot with a small amount of air flow through an inner nozzle, which could be explained with the enhanced soot formation process due to the oxygenated species assisted pyrolysis. The increase of air flow rate up to 250 sccm transformed a soot emitting flame into a non-emitting flame without inner flame. Further increase of air flow rate created an inner flame and changed the flame into a soot emitting flame. When air flow rate was decreased again, the flame was changed back to a emitting flame; however, the presence of an inner flame altered the soot formation and oxidation characteristics of the flame and enhanced the soot formation process. The oxygenated species assisted pyrolysis, the radiation heat loss and the temperature effect of inner flames would determine the characteristics of soot production/oxidation of an ethylene diffusion flame with air flow inside.

층류확산화염의 불안정성에 대한 매연생성 특성의 역할

남연우(Younwoo Nam),이원남(Wonnam Lee) 한국연소학회 2010 한국연소학회지 Vol.15 No.3

In this study, soot formation characteristics on the instability of laminar diffusion flames were investigated experimentally using a concentric co-flow burner. When a small amount of air was supplied through an inner nozzle, a stable propane laminar diffusion flame became unstable and began to oscillate mainly due to the dilution effect. The increase of air flow rate transformed an oscillating non-sooting flame into a stable nonsooting flame. When the air flow rate was continuously increased an inner flame was formed and the flame was changed to an oscillating sooting flame, an oscillating non-sooting flame and finally a stable non-sooting hollow flame. When the air flow rate was decreased, a non-sooting hollow flame was eventually changed back to a stable non-sooting flame. The presence of an inner flame, however, altered the soot formation characteristics of a flame. More soot production was observed with the presence of an inner flame. The increased or decreased soot formation/oxidation rates, the radiation heat loss, and the heating effect of inner flames are most likely to be responsible for the observed instability of laminar diffusion flames.