딥러닝 기반 초음파 홀로그램 생성 알고리즘 개발

이문환,황재윤,Lee, Moon Hwan,Hwang, Jae Youn 한국음향학회 2021 韓國音響學會誌 Vol.40 No.2

Recently, an ultrasound hologram and its applications have gained attention in the ultrasound research field. However, the determination technique of transmit signal phases, which generate a hologram, has not been significantly advanced from the previous algorithms which are time-consuming iterative methods. Thus, we applied the deep learning technique, which has been previously adopted to generate an optical hologram, to generate an ultrasound hologram. We further examined the Deep learning-based Holographic Ultrasound Generation algorithm (Deep-HUG). We implement the U-Net-based algorithm and examine its generalizability by training on a dataset, which consists of randomly distributed disks, and testing on the alphabets (A-Z). Furthermore, we compare the Deep-HUG with the previous algorithm in terms of computation time, accuracy, and uniformity. It was found that the accuracy and uniformity of the Deep-HUG are somewhat lower than those of the previous algorithm whereas the computation time is 190 times faster than that of the previous algorithm, demonstrating that Deep-HUG has potential as a useful technique to rapidly generate an ultrasound hologram for various applications.

The Effects of Taping on Metacarpophalangeal Disorders of the Thumb

이문환,김응창,이수연,박래준,Lee, Moon-Hwan,Kim, Eung-Chang,Lee, Soo-Yeon,Park, Rae-Joon The Korean Society of Physical Therapy 2010 대한물리치료학회지 Vol.22 No.1

Purpose: This study investigated the effect of taping therapy on metacarpophalangeal (MCP) disorders of the thumb. Methods: Twenty eight patients were enrolled in this study. They were randomly assigned to experimental (n=16) or a control group (n=12). The experimental and control groups received Ultrasound (Gymna Pulson 200) operating at a frequency of 3MHz and an intensity of $1.0W/cm^2$ with a 100% duty cycle for 10 minutes. The experimental group received, additionally, taping using Kinesiotape on the injured thumb. The following parameters were measured:pain during rest and flexion of the thumb, tenderness, range of motion (ROM), pinch and spherical grip power pre- and post-treatment. This study was carried out 3 days per week throughout the 2-week treatment. Results: There were significant improvements in pain during rest and flexion of the thumb, tenderness, ROM, pinch and spherical grip power between pre- and post-treatment times in both groups (p<0.05). However, there was a significant difference in all parameters between the experimental and control groups (p<0.05). Finally, the satisfaction level after intervention was significantly higher in the experimental group than in the control group (p<0.05). Conclusion: Taping is effective for treating pain and dysfunction in patients with thumb disorders.

고해상도 기후시나리오를 이용한 서울지역 배수시스템의 기후변화 영향 분석

이문환,김재표,배덕효,Lee, Moon-Hwan,Kim, Jae-Pyo,Bae, Deg-Hyo 한국수자원학회 2015 한국수자원학회논문집 Vol.48 No.5

본 연구에서는 고해상도 기후시나리오를 이용하여 국내 대표 도시 지역인 서울특별시를 대상으로 기준기간(1971~2000년) 대비 미래기간 2020s (2011~2040년), 2050s (2041~2070년), 2080s (2071~2100년)의 기후변화에 따른 배수시스템의 영향을 평가하였다. 이를 위해 과거 관측 강수량 자료는 기상청 관할 기상관측소와 자동기상관측망 자료를 이용하였으며, 기후변화 시나리오는 RegCM3과 Sub-BATS 기법을 통해 역학적 상세화된 $5{\times}5km$ 해상도 기반의 시단위 강수량 자료를 생산하였다. 과거기간 대비 미래기간 확률강우량의 변동성을 비교한 결과 과거기간 대비 2080s의 확률강우량 증가율은 28~54%로 나타났으며, 특히 지속시간 3시간, 6시간, 24시간 확률강우량의 증가폭이 크게 나타났다. 또한 배수시스템의 기후변화 영향을 직접적으로 분석하기 위해 XP-SWMM을 이용하여 유출해석을 수행하였다. 평가 결과, 강우강도 증가로 인해 과거기간 대비 미래 3기간에 공릉1, 서초2, 신림4 배수분구의 침수발생 맨홀 수와 월류량이 크게 증가하였다. 이러한 결과는 현재 구축되어 있는 서울시 배수시스템은 기후변화에 취약함을 나타내고 있으며, 이에 대응하기 위해 다양한 기후변화 적응대책이 요구됨을 의미한다. Climate change impact on urban drainage system are analyzed in Seoul by using high-resolution climate change scenario comparing 2000s (1971~2000) with 2020s (2011~2040), 2050s (2041~2070) and 2080s (2071~2100). The historical hourly observed rainfall data were collected from KMA and the climate change scenario-based hourly rainfall data were produced by RegCM3 and Sub-BATS scheme in this study. The spatial resolution obtained from dynamic downscaling was $5{\times}5km$. The comparison of probability rainfalls between 2000s and 2080s showed that the change rates are ranged on 28~54%. In particular, the increase rates of probability rainfall were significant on 3, 6 and 24-hour rain durations. XP-SWMM model was used for analyzing the climate change impacts on urban drainage system. As the result, due to the increase of rainfall intensities, the inundated areas as a function of number of flooded manhole and overflow amounts were increasing rapidly for the 3 future periods in the selected Gongneung 1, Seocho 2, Sinrim 4 drainage systems. It can be concluded that the current drainage systems on the selected study area are vulnerable to climate change and require some reasonable climate change adaptation strategies.

스케일 특성을 이용한 미래 확률강우량 산정기법의 적용성 평가

이문환,신상훈,배덕효,Lee, Moon-Hwan,Shin, Sang-Hoon,Bae, Deg-Hyo 한국수자원학회 2012 한국수자원학회논문집 Vol.45 No.3

본 연구에서는 스케일 특성을 이용하여 기후변화에 따른 일단위 이하의 극한강우를 평가할 수 있는 방법을 제안하였으며, 서울을 비롯한 6개 주요 기상관측소 지점을 대상으로 적용성을 평가하였다. 우선, 과거 관측자료를 이용하여 스케일 특성을 이용한 확률강우량 산정기법의 적용성을 평가하였으며, 평가 결과 빈도분석과 스케일특성으로 산정된 확률강우량의 절대상대오차가 10% 내외의 범위를 보였다. 또한 기준기간의 기후시나리오를 이용하여 적용성 평가를 수행한 결과 100년 빈도이내에서 20% 내의 절대상대오차를 보였다. 평가 결과를 통해 본 연구에서 적용한 스케일 특성 기법은 미래 확률강우량 산정 시 신뢰성 있는 결과를 도출할 수 있을 것으로 판단된다. The objectives of this study are to suggest the method for estimation of sub-daily extreme rainfall under climate change using scale properties and to assess the application in the 6 major weather stations including Seoul site. First, the proposed method was assessed by past observations. As the results, absolute relative errors of probability rainfall quantiles estimated by frequency analysis and scale property method show approximately 10% in the all durations. And as the result of application climate scenario, absolute relative errors of rainfall quantiles between two method show approximately 20%. From the results, the scale property method on this study will be derive as the reliable results.

협착성 건초염에 대한 키네시오 테이핑치료의 효과

이문환,마상렬,이현희,김성학,박래준,Lee, Moon-Hwan,Ma, Sang-Yeol,Lee, Hyeon-Hee,Kim, Seong-Hak,Park, Rae-Joon 대한물리치료학회 2007 대한물리치료학회지 Vol.19 No.1

Purpose: Stenosing tenosynovitis is a stenosing condition of the sheath of the abductor pollicis longus and extensor pollicis brevis tendons at the radial styloid process. The purpose of this study was to investigate the effects of kinesio taping on the pain and grip power in patients with de Quervain's disease. Method: 20 female with de Quervain's disease was recruited. This procedure was performed with or without taping procedure. Pain levels were assessed using a visual analogue scale, and spherical and pinch grip powers were assessed using a dynamometer. Results: 1. Resting pain, Finkelstein test pain, and Tenderness using VAS scale was showed significantly reduced after taping application(p<0.01). 2. Spherical grip power using dynamometer was showed significantly increased after taping application(p<0.01). 3. Pinch grip power using dynamometer was showed significantly increased after taping application(p<0.01). Conclusion: So we thought that kinesio taping therapy had effects on the pain release and grip power increasing to the small or local muscle groups and joints.

Al₂O₃-TiO₂ 용사코팅된 유리의 입자충격 에너지에 따른 손상거동

이문환(Moon-Hwan Lee) 한국기계가공학회 2012 한국기계가공학회지 Vol.11 No.6

Fracture of brittle material due to dynamic load such a particle impact has been reported by many researchers as the fracture behavior by variation of stress for a short minute. Especially, the brittle material, such a ceramic, applied to the structural component of machine, is considered as the important project. In order to evaluate the improvement of impact resistance, the particle impact test for the Al₂O₃-TiO₂ coated glass is practiced. And then, the damage variation according to the impact energy of steel ball was evaluated. There was a large improvement by the ceramic coating on the surface of a glass substrate. The damage volume was especially imported to evaluate damage behavior in quantity. These data were plotted on logarithmic coordinate and experimental equations were induced by data analysis based on test results. And the variation of critical energy for crack initiation was analyzed with critical impact energy when each crack occurs.

지능형 제품에서의 자동화가 감성적 경험 형성에 미치는 영향

이문환(Lee Moon-Hwan),남택진(Nam Tek-Jin) 한국디자인학회 2011 디자인학연구 Vol.24 No.2

기후변화에 따른 저유량 전망 및 불확실성 분석

이문환(Lee, Moon Hwan),배덕효(Bae, Deg Hyo) 한국기후변화학회 2016 한국기후변화학회지 Vol.7 No.4

물정보 통합 서비스 실현 방안

이문환 ( Lee Moon Hwan ),현진호 ( Hyun Jin Ho ),김영철 ( Kim Young Cheol ) 한국물환경학회 2023 공동춘계 학술발표회 논문집 Vol.2023 No.0

안정된 햅틱 인터페이스를 위한 비선형가상커플링

이문환(Moon-Hwan Lee),이두용(Doo Yong Lee) 제어로봇시스템학회 2003 제어·로봇·시스템학회 논문지 Vol.9 No.8