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수온약층이 존재하는 천해역에서 단기간 음속구조 변화에 따른 음향 신호 전달 변동에 관한 연구
정동영,김시문,변성훈,임용곤,Jeong, Dong-Yeong,Kim, Sea-Moon,Byun, Sung-Hoon,Lim, Yong-Kon 한국음향학회 2015 韓國音響學會誌 Vol.34 No.1
수중음향 전달채널의 임펄스 응답(Channel Impulse Response: CIR)은 음속구조(Sound Speed Profile: SSP)의 영향을 받으며, 채널 임펄스 응답의 변화는 수중음향통신 시스템의 성능에 중요한 영향을 미친다. 음속분포의 변화는 단기간 내에서도 나타날 수 있으며, 수중음향 모뎀 설계 시 반드시 고려되어야 한다. 이 논문은 2013년도에 제주도 동방해역에서 수행된 JACE13에서 취득된 데이터를 기반으로 음선전달 수치해석을 통해 단기간 동안 시간에 따라 변화하는 음속구조가 음향 신호 전달에 미치는 영향을 통계적으로 분석한 결과를 제시한다. 분석결과 송 수신기 수심별로 채널 임펄스 응답의 변화가 다양하게 나타나며, 송 수신기 수심이 깊을수록 음속구조의 변동에 따른 음향신호 전달 양상의 변화는 작아지고, 신호 준위가 높게 나타난다. 이 연구에서의 다양한 거리, 송, 수신기 수심에 따라 얻어진 채널 임펄스 응답 추정 결과는 수온약층에서의 하방굴절로 인한 연속된 해저면 반사와 작은 해저면 반사손실이 장거리 신호 전파에 중요한 요인이 될 수 있음을 보여주며, 시변동성을 갖는 해양환경에서의 수중 음향 통신은 시간에 따라서 성능이 충분히 달라질 수 있다는 것을 보여준다. Underwater acoustic channel impulse responses (CIR) are influenced by sound speed profile (SSP), and the variation of CIR has significant effects on the performance of underwater acoustic communication systems. A significant change of SSP can occur within a short period, which must be considered during the design of underwater acoustic modems. This paper statistically analyzes the effect of the variation of SSP on the long-range acoustic signal propagation in shallow-water with thermocline using numerical modeling based on the data acquired from JACE13 experiment near Jeju island. The analysis result shows that CIR changes variously according to the SSP and the depth of the transmitter and receiver. We also found that when the transmitter and receiver are deeper, the variation of sound wave propagation pattern is smaller and signal level becomes higher. All CIR obtained in this study show that a series of bottom reflections due to downward refraction and small bottom loss in the shallow water with thermocline can be very important factor for long-range signal transmission and the performance of underwater acoustic communication system in time varying ocean environment can be very sensitive to the variation of SSP even for a short period of time.
VGT와 EGR이 장착된 디젤엔진의 공기순환계 모델에 관한 연구
정동영(Dong-Young Jeong),정재우(Jae-Woo Chung),강정호(Chung-Ho Kang),김남호(Nam-Ho Kim),정진은(Jin-Eun Chung) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
The recent Diesel engine is to install VGT(variable geometry turbocharger) to increase the engine displacement per the power, to reduce the CO2 generation by increasing the BSFC and to minimize the turbo-reg at low speed-load points. And the EGR system is installing for reducing the NOx generation. The VGT and EGR were operated complexly in the engine intake and the exhaust system. Therefore, this study focuses to modify VGT dimensionless model using the flow, efficiency and power parameters which are temperature, pressure and mass flow. and this models were developed to predict the intake and the exhaust state in engine. In case of the Combination with the model which are turbocharger model, intercooler model, exhaust gas model, it is possible to predict intake and exhaust state which are boost temperature, pressure ratio, after intercooler gas temperature, before the turbine pressure and the turbine vane duty using just mass air flow rate within reasonable errors. And in case of introduce the another additional independent parameter, it is possible to increase the prediction accuracy.
유동 에너지 균형을 이용한 EGR 측정 기술 개발에 관한 연구
정동영(Dong-Young Jeong),정재우(Jae-Woo Chung),김남호(Nam-Ho Kim),강정호(Chung-Ho Kang),서영호(Young-Ho Seo),정수진(Soo-Jin Jeong) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
This study focuses the another measurement way of EGR rate without Horiba exhaust analyser. it uses the flow energy balance which is intercooler heat rate plus EGR gas heat rate equals intake manifold. The result of comparison of engine test, the heat transfer should be considered especially Hot HP EGR loop system because EGR gas temperature is higher than cooled HP EGR loop. The correction coefficient considering to heat transfer was fined by using heat rate error for NEDC mode test with 2000cc common rail DME engine. The result of mode test shows the validity of the measurement of EGR rate through the comparison of NOx.
LP EGR 적용을 위한 승용 디젤 엔진 보정 기법에 관한 연구
정동영(Dongyoung Jeong),정재우(Jaewoo Chung),김남호(Namho Kim),강정호(Chungho Kang),김태진(Taejin Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Diesel engine technology is developing to satisfy strong exhaust gas regulations and lower fuel economy. In the event of study, the HP EGR system which is to reduce NOx generation of the engine emission is changed to LP EGR system which investigate in NOx and BSFC respects. In structural alterations to the LP EGR, the pressure drop should be minimized in EGR gas path. And Applying the LP EGR is of benefit to reduce the NOx generation above 40% in same BSFC level, in this case, the vane control of variable geometry turbocharger is controlled in maximum compressor efficiency area, and the LP EGR valve is operated the wipe open state, the back pressure valve is controlled to consider limit A/F and reduced BSFC. And the equation of the mass flow through the nozzle is modified for EGR valve and back pressure valve. In using modified equation predicts the pressure of before back pressure valve and accompanying pressure is used to predict EGR rate. And that the predicted EGR rate is verified to compare with engine test data.
정동영(Dong Yeong Jeong),한성호(Sung H. Han),최승문(Seungmoon Choi),이민규(Mingyu Lee),강해우(Haewoo Kang),한상윤(Sangyoon Han),이효승(Hyo Seung Lee),윤겨레(Gyeore Yun),이지완(Jiwan Lee),이다진(Dajin Lee) 대한인간공학회 2019 대한인간공학회 학술대회논문집 Vol.2019 No.5
The aim of this study is to classify the information that motion and haptic effects of 4D cinema seat describe. 4D technology can add physical effects such as motion, vibration, and wind to audiovisual contents, enabling users to have more realistic and immersive experiences. Specifically, it is known that motion and haptic effects can improve an audience’s immersion. The information that motion and haptic effects describe should be explored to systematically design audience-friendly effects. Eight graduate students in the field of user experience or haptics participated in the experiment. They observed what motion and haptic effects of a 4D cinema seat describe and wrote them in a note while watching five 4D films. After watching each 4D film, they had a discussion and classified the effects based on the information the effects describe. The motion and haptic effects were classified into four categories: object movement, camera viewpoint, sound, and circumstances. The classification would be useful to plan systematically user experience studies of 4D effects. The results of this study might also help to provide design insights to the 4D effect designers.
지방자치단체장의 윤리적 리더십에 미치는 영향요인에 관한 연구
정동영(Jeong, Dong-Yeong),최상한(Choi, Sanghan) 한국지방정부학회 2017 지방정부연구 Vol.21 No.1
본 연구는 최근 지방자치단체장의 윤리적 리더십에 대한 중요성이 강조되는 상황에서 지방자치단체장의 윤리의 식은 행정전반의 윤리적 기준을 형성하는 주요 요인이라는 것에 기초하여 출발하였다. 이를 위해 본 연구는 선행연 구의 검토를 통해 지방자치단체장의 윤리적 리더십에 영향을 주는 요인으로 상사신뢰, 정서적 몰입, 직무성과, 직무만족도, 역할갈등을 설정하였다. 그리고 이러한 요인들의 영향관계를 파악하기 위하여 경상남도 기초자치단체의 공무원을 대상으로 설문조사를 실시하였다. 본 연구를 수행하기 위한 분석방법으로는 SPSS 23.0을 이용하였다. 분석결과, 지방자치단체 구성원들의 상사 신뢰, 정서적 몰입, 직무만족도는 지방자치단체장의 윤리적 리더십에 정 (+)의 영향을 미치는 것으로 나타났다. 그러나 역할갈등은 지방자치단체장의 윤리적 리더십에 부(-)의 영향을 미치는 것으로 나타났다. 그리고 직무성과는 지방자치단체장의 윤리적 리더십에 영향을 미치지 않는 것으로 나타났다. 따라서 지방자치단체장의 윤리적 리더십을 강화하기 위해서는 구성원들의 상사신뢰, 정서적 몰입, 직무만족을 제고할 필요가 있다고 판단된다. 윤리적 리더십을 종속변수로 설정한 것은 선행연구와 차별화되는 것이고, 향후 연구에서 윤리적 리더십의 영향요인에 대한 탐색의 기초자료로 유용하게 활용될 수 있을 것이다. This study initiated on the ground that under the circumstances that ethical leadership is being emphasized, the ethics of mayors is a main factor forming ethical criterion of administration in general. This study selected trust in the leader, affective commitment, organizational performance(job performance, job satisfaction), role conflict as factors affecting ethical leadership This study conducted a survey of public officials of basic local governments in Gyeongsangnam-do Province. As a result of the analysis, trust in the leader, affective commitment, job satisfaction of organizational performance of the members of local governments were seen to have an positive(+) effect on ethical leadership Role conflict was seen to have an negative(-) effect on ethical leadership. And out of organizational performance, job performance was seen to have no effect on ethical leadership of the mayors in Local Governments.