예기치 못한 후두 입구 협착으로 인한 환기 부전 상황에서의 비디오 후두경의 유용성 1예

문정환,이선홍,강봉진,Moon, Jeong Hwan,Lee, Sun Hong,Kang, Bong Jin 대한후두음성언어의학회 2016 대한후두음성언어의학회지 Vol.27 No.2

Although many factors associated with difficult intubation have been known, predictors of difficult mask ventilation are not well known. We experienced a case of nearly complete airway obstruction following usual anesthetic induction which needed various emergency treatments. The patient had a preoperative diagnosis of contact granuloma of right posterior vocal cord and bilateral vocal cord palsy but later was found out as invasive laryngeal cancer. Upon the surgical field of view, both vocal cords were showing significantly thickened and fixated appearance and was considered as in the critical narrowing state with the potential of complete obstruction. Using $C-MAC^{(R)}$ video laryngoscope we were able to see the narrowed vocal cord and choose proper size of endo-tracheal tube. Consequently, intubation was successfully done and operation was conducted. From this case, we have lessons that physicians should examine the patient's airway more carefully in case of laryngeal mass and prepare emergency measures.

해역별 기름유출사고 위험도 매핑 프로그램 개발에 관한 연구

문정환,윤종휘,Moon, Jung-Hwan,Yun, Jong-Hwui 해양환경안전학회 2016 해양환경안전학회지 Vol.22 No.5

본 연구에서는 시스템 다이내믹스 기법을 적용하여 기름유출사고의 동태적 현상을 분석하고, 기름유출 사고초기 사고해역의 위험성을 판단할 수 있도록 기름유출사고의 사고이력에 기초하여 해역별 위험도를 산출하고 위험도 프로그램을 개발하였다. 이를 통해 다음의 결과를 얻었다. 첫째, 기름유출사고 고유데이터를 기초하여 전혀 다른 변수를 단일점수로 산출했으며, 해역별 기름유출 위험도를 정량적인 수치로 산출했다. 둘째, 산출된 사고별 위험도로 해역별 위험도를 도출했으며 이용의 극대화를 위해 스마트기기에서 실행기 가능한 프로그램을 구현했다. 셋째, 우리나라 해역별 기름오염 위험도를 직접적으로 비교평가가 가능해졌으며, 긴급시 신속한 의사결정을 유도할 수 있다. 기름유출사고 위험도를 특별한 제약없이 편리하고 신속하게 판단할 수 있게 됨에 따라 기름유출사고의 선제적인 대비(전략)에 도움을 줄 수 있을 것이라 판단된다. A study was conducted to analyze the oil spill dynamic state using system dynamics method, and to developed regional risk program based on oil spill history for better judgement of the situation at the early stage of oil spill. Results were obtained as follows: Firstly, various variables were calculated by a score based on raw data of oil spill history in Korea. Regional oil spill risk was also calculated in a quantitative way. Secondly, calculated regional oil spill risk was analyzed and programmed with a help of smart-device for better use. Thirdly, comparison of oil spill risk between regions became possible and regional oil spill risk program proved to be useful in prompt decision under urgent situation in response to oil spill at sea. Convenient and quick oil spill risk without special restrictions have been able to determine. and it can help in anticipative preparation (strategy) for oil spills.

후두골격수술의 원칙 및 합병증

문정환,손영익,Moon, Jeong-Hwan,Son, Young-Ik 대한후두음성언어의학회 2011 대한후두음성언어의학회지 Vol.22 No.1

Laryngeal framework surgery comprises medialization laryngoplasty and arytenoid adduction. Since their introduction in the 1970s, these procedures have become standard treatments for vocal fold paralysis and glottal incompetence. However, frequency of laryngeal framework surgery is conjectured to relatively decrease along with the introduction of injection laryngoplasty. In this manuscript, indications for laryngeal framework surgery were highlighted in contrast to those of injection laryngoplasty. The authors introduced the basic concepts and principles as well as surgical techniques of laryngeal framework surgery. Even though the incidence of major and/or minor complications after laryngeal framework surgery is not high, surgeons should be well aware of its possible complications and they should be familiar with tips and know-how to avoid or cope with complications.

레이저 후두미세수술의 원칙

문정환,이상준,정필상,Moon, Jeong Hwan,Lee, Sang Joon,Chung, Phil-Sang 대한후두음성언어의학회 2013 대한후두음성언어의학회지 Vol.24 No.1

Laser laryngeal microsurgery is currently the primary method of treatment of various laryngeal diseases. The development of laryngeal microsurgery came from the introduction of a small spot $CO_2$ laser micromanipulator and more precise microlaryngeal instruments. $CO_2$ laser laryngeal microsurgery has enabled very precise surgery because it has small focus size and hemostatic effect. There are some limitations to the use of the $CO_2$ Laser such as adjacent tissue damage and vocal fold scarring. These problems can be minimized through understanding the mechanisms by which lasers function and correctly manipulating the parameters under a surgeon's control. We should also recognize the safety of $CO_2$ laser for the surgeon to precisely perform the procedure.

Gate-Bias Control Technique for Envelope Tracking Doherty Power Amplifier

문정환,김장헌,김일두,김정준,김범만,Moon, Jung-Hwan,Kim, Jang-Heon,Kim, Il-Du,Kim, Jung-Joon,Kim, Bum-Man The Korean Institute of Electromagnetic Engineerin 2008 한국전자파학회논문지 Vol.19 No.8

본 논문에서는 선형성 증가를 위해 도허티 증폭기의 게이트 바이어스를 조정하는 방식을 제시하였다. 도허티 증폭기의 선형성 향상은 출력 결합 지점에서의 고조파 상쇄를 통해 이루어진다. 하지만 고조파의 상쇄는 그 크기와 위상이 출력 지점에서 같은 크기와 서로 다른 위상을 가지고 있어야 이루어질 수 있는데, 넓은 출력 전력 범위에서 위와 같은 조건을 만족시키는 것은 쉽지 않다. 선형성 증가를 위해 도허티 증폭기의 캐리어 증폭기와 피킹 증폭기의 선형성 특성을 입력 전력과 각 증폭기의 게이트 바이어스를 조정함으로써 살펴보았다. 살펴본 특성을 기본으로 하여 고조파 상쇄 전력 범위를 증가시키기 위해, 각 전력 레벨에 맞는 게이트 바이어스를 증폭기에 인가하였다. 게이트 바이어스 제어를 통한 선형성 향상을 알아보기 위해, 2.345 GHz에서 Eudyna사의 10-W PEP GaN HEMT EGN010MK 소자를 이용하여 도허티 전력 증폭기를 설계하였고, $P_{1dB}$로부터 10 dB back-off 지점인 33 dBm에서 고효율과 고선형성을 위해 최적화 되었다. WCDMA 1-FA 신호에 대해 제안된 게이트 바이어스 컨트롤 된 도허티 증폭기는 2.8 dB의 선형성 개선을 확인할 수 있었으며, 26 %의 PAE를 확인할 수 있었다. 또한, 802.16-2004 신호에 대해 RCE가 2 dB 증가됨을 확인할 수 있었다. The gate-biases of the Doherty power amplifier are controlled to improve the linearity performance. The linearity improvement mechanism of the Doherty amplifier is the harmonic cancellation of the carrier and peaking amplifier at the output power combining point. However, it is difficult to cancel the harmonic power for the broader power range because the condition for cancelling is varied by power. For the linearity improvement, we have explored the linearity characteristic of the Doherty amplifier according to the input power and gate biases of the carrier and peaking amplifier. To extend the region of harmonic power cancellation, we have injected the proper gate bias to the carrier and peaking amplifier according to the input power levels. To validate the linearity improvement, the Doherty amplifier is designed using Eudyna 10-W PEP GaN HEMT EGN010MKs at 2.345 GHz and optimized to achieve a high linearity and efficiency at an average output power of 33 dBm, backed off about 10 dB from the $P_{1dB}$. In the experiments, the envelope tracking Doherty amplifier delivers a significantly improved adjacent channel leakage ratio performance of -37.4 dBc, which is an enhancement of about 2.8 dB, maintaining the high PAE of about 26 % for the WCDMA 1-FA signal at an average output power of 33 dBm. For the 802.16-2004 signal, the amplifier is also improved by about 2 dB, -35 dB.

GUI기법을 이용한 Load Flow 교육용 시뮬레이터 개발

문정환(Jeong-Hwan Moon),김영용(Young-Yong Kim),장세환(Se-Hwan Jang),류승오(Seung-Oh Ryu),박준호(June-Ho Park) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11

This paper presents a Windows graphic developed by the authors for the education and training of power system Object-oriented programming is a major trend in computer software because it increases flexibility of large-scale software systems. An efficient platform for power system simulation applications has been proposed. This paper presents an intuitive Windows-based program for the power system analysis. The advantages of the object-oriented approach are demonstrated with an implementation of the graphical program. It provides a graphical interface for designing the one-line diagram of the bus and analyzing the output of the simulations. A graphical editor to visually edit the power system, diagram, results processing and exporting and graphic presentations.

Al-Si 코팅층 Laser Ablation 변수에 의한 LWB 보론강판의 기계적 특성 평가

문정환(J. H. Moon),이민식(M. S. Lee),강충길(C. G. Kang) 한국소성·가공학회 2011 소성가공 : 한국소성가공학회지 Vol.20 No.8

해상방제능력 향상을 위한 대형 방제선 도입의 필요성과 운용에 관한 연구

문정환(Jung-Hwan, Moon),윤종휘(Jong-Hwui Yun) 한국항해항만학회 2009 한국항해항만학회 학술대회논문집 Vol.2009 No.추계

2007년 우리나라 서해에서 발생한 Hebei Spirit호 사고와 1997년 일본의 Nakhodka호 유출사고, 2002년 스페인의 Prestige호 유출사고 등 재난적 유류유출사고를 통해서 대형 방제선박의 필요성을 확인하고, 대형 방제선의 도입과 도입이후, 방제 외 활용방안을 제시함으로 빈번하지는 않지만 천문학적 피해를 발생하는 재난적 유류유출사고에 효율적이고 효과적으로 대응하고자 한다. Needs of Large Oil Recovery Vessels will be checked by Hebei Spirit Oil Spill in Korea in 2007, Nakhodka Oil Spill in Japan in 1997, Prestige Oil Spill in Spain in 2002. and offer a efficient proposals for practical use besides Catastrophic Oil Spill Response

혼합 P2P 보안 멀티캐스트 구현

문정환(Jung-Hwan Moon),송기범(Gi-Beom Song),방극인(Keug-in Bang),안성수(Seong-Soo Ahn),이준(Joon Lee) 한국멀티미디어학회 2003 한국멀티미디어학회 학술발표논문집 Vol.2003 No.2

발전플랜트 지중 냉각수 취수시스템의 서지 해석에 관한 연구

문정환(Junghwan Moon),김진호(Jin-Ho Kim),이승철(Seung-Chul Lee) 대한설비공학회 2021 설비공학 논문집 Vol.33 No.11

In this study, surge analysis was performed to investigate the risk for overflow in a pump station of power plant with different design cases. In case of a reference model with intake bay length of 36 m, the water level of pump station increased to a maximum of 4.1 m if all intake pumps stopped. This result means that there is no overflow at the pump station, the launching shaft, or the end shaft. In case of alternative model with inlet bay length shorter than the reference model by 9 m, there was no possibility of overflow occurrence since the water level of pump station increased up to 4.4 m. If four pumps were tripped, the water level of pump station increased under the height of structure in both reference and alternative models. It was found that the stability of sea water intake system could be secured in spite of a reduction of inlet bay length for construction cost reduction.