플랭크 운동 이후 감각실조로 발현한 척수경색

안정우,전석휘,팽성화,오성일 대한근전도전기진단의학회 2019 대한근전도 전기진단의학회지 Vol.21 No.2

Spinal cord infarctions cause acute myelopathy with severe and long-term sequelae. Spinal cord infarction generally presents with abrupt onset of limb weakness, sensory disturbance, dysfunction of urination, or pain. Spinal cord infarction may be caused by surgery-related complications, aortic dissection, vasculitis, cardiac embolism, and surfing. We describe a case of a 67-year-old female who underwent a plank exercise the previous day, followed by a sensory abnormality of the lower extremity and gait disorder in the morning. The patient was diagnosed with spinal cord infarction with acute myelopathy through clinical features, diffusion-weighted magnetic resonance imaging, and neurophysiologic study. Spinal cord infarction is a rare disease and may be caused by plank exercise including Valsalva maneuver; therefore, clinicians should be cautious in this situation.

다양한 지구통계기법의 지하매질 예측능 및 적용성 비교연구

안정우,정진아,박은규,Ahn, Jeongwoo,Jeong, Jina,Park, Eungyu 한국지하수토양환경학회 2014 지하수토양환경 Vol.19 No.4

In the present study, a few of recently developed geostatistical models are comparatively studied. The models are two-point statistics based sequential indicator simulation (SISIM) and generalized coupled Markov chain (GCMC), multi-point statistics single normal equation simulation (SNESIM), and object based model of FLUVSIM (fluvial simulation) that predicts structures of target object from the provided geometric information. Out of the models, SNESIM and FLUVSIM require additional information other than conditioning data such as training map and geometry, respectively, which generally claim demanding additional resources. For the comparative studies, three-dimensional fluvial reservoir model is developed considering the genetic information and the samples, as input data for the models, are acquired by mimicking realistic sampling (i.e. random sampling). For SNESIM and FLUVSIM, additional training map and the geometry data are synthesized based on the same information used for the objective model. For the comparisons of the predictabilities of the models, two different measures are employed. In the first measure, the ensemble probability maps of the models are developed from multiple realizations, which are compared in depth to the objective model. In the second measure, the developed realizations are converted to hydrogeologic properties and the groundwater flow simulation results are compared to that of the objective model. From the comparisons, it is found that the predictability of GCMC outperforms the other models in terms of the first measure. On the other hand, in terms of the second measure, the both predictabilities of GCMC and SNESIM are outstanding out of the considered models. The excellences of GCMC model in the comparisons may attribute to the incorporations of directional non-stationarity and the non-linear prediction structure. From the results, it is concluded that the various geostatistical models need to be comprehensively considered and comparatively analyzed for appropriate characterizations.

리페어 FPC 본더 개발

안정우,서지원,Ahn Jung-Woo,Seo Ji-Weon 한국반도체디스플레이기술학회 2005 반도체디스플레이기술학회지 Vol.4 No.4

This article contains the development of FPC bonder that used for repair or trial product. Nowadays, in FPO module process (including PDP) accept the thermo-compress bonding method when attach FPC(Flexible Printed Circuit Board), TCP(Tape Carrier Package) and COF(Chip on the FPC) by ACF(Anisotropic Conductive Film). This system consists of ACF attachment part, pre-bonding part, main bonding part, loading / unloading part. This composition is a stand-alone system, not an in-line system. Hereafter, this composition should be developing into in-line system in all area of FPD industry.

일 농촌지역 주민에서 우울증상과 심박변이도의 관계

안정우(Jung Woo Ahn),한창우(Chang Woo Han),최보율(Bo Yul Choi),김유미(Yu Mi Kim),남정현(Jung Hyun Nam),최준호(Joonho Choi),김석현(Seok Hyeon Kim) 대한스트레스학회 2008 스트레스硏究 Vol.16 No.3

목적: 이 연구의 목적은 우울증 진단을 받지 않은 일반 인구 집단에서 심박변이도(heart rate variability, HRV)와 우울증과의 연관성을 조사하여 우울증상에 따른 일반 인구 집단에서도 HRV의 변화가 있는지를 알아보는데 있다. 방법:경기도 소재 ○○군의 주민 중 건강증진 프로그램에 참가한 155명을 대상으로 하였다. 이중 HRV에 영향을 줄 수 있는 신체 질환을 가진 58명과 Beck’s depression inventory (BDI) 작성을 못한 2명을 배제한 95명의 short term electrode HRV를 측정하였고 BDI를 이용하여 우울증상을 조사하였다. 이들을 대상으로 HRV와 BDI 간의 연관성을 통계적으로 분석하였다. 결과: BDI와 HRV의 지표들 중 SDNN (standard deviation of the normal to normal interval), TP (total power), HF (high frequency), LF (low frequency), VLF (very low frequency), pNN50 (전체 normal to normal interval들 중 연속된 Normal to Normal Interval들의 변이가 50 ms 이상인 간격들의 비)이 유의하게 음의 상관관계를 가진 것으로 나타났으며 이 중 LF, HF, RMSSD (the square root of the mean squared differences of successive normal to normal intervals)는 BDI값을 이용하여 우울증을 중증 정도로 구분했을 때 유의하게 차이가 있었다. 결론: HRV의 일부 지표는 일반 인구에서 잠재성의 우울 증상의 정도를 측정할 수 있었다. Purpose: The purpose of this study is to investigate relationship between HRV (heart rate variability) and depressive symptoms in general population. This study was designed to examine the correlation of HRV and depressive symptom in general rural population. Methods: In 155 participants lived in the anonymous rural area of Gyeonggi-do, Korea, they participated in health promotion program with short term electrode HRV test and BDI (Beck’s depression inventory) self-report. Two participants were excluded due to fail to make out BDI and 58 participants were excluded because of some kinds of heart problems which were found after electrocardiogram and echocardiography exam of the health promotion program. We analyze HRV and BDI of remaining 95 subjects. Results: Our results showed that SDNN (standard deviation of the normal to normal interval), total power (TP), low frequency (LF), high frequency (HF) had negative correlation with BDI score, but only pNN50 (the proportion derived by dividing the number of interval differences of successive normal to normal intervals greater than 50 ms by the total number of normal to normal intervals) had positive correlation with BDI score. Also HF, LF and RMSSD (the square root of the mean squared differences of successive normal to normal intervals) are decreased by BDI severity grades increasing. Conclusion: In this findings of our study, some HRV variables seem to reflect subclinical depressive symptom severity in general rural population.

Bi-directional PQ-RRT*를 이용한 유도 시스템 개발 연구

안정우(Jung Woo An),안준영(Jun-Young An),우지원(Ji Won Woo),임민규(Mingyu Lim),김창주(Chang-joo Kim) 한국항공우주학회 2021 한국항공우주학회 학술발표회 논문집 Vol.2021 No.11

초임계 환경으로 분사되는 액체 연료 제트의 분사 거동 특성

안정우(Jeongwoo An),최명환(Myeung Hwan Choi),이준(Jun Lee),구자예(Jaye Koo) 한국항공우주학회 2022 韓國航空宇宙學會誌 Vol.50 No.5

쉐도우그래프(Shadowgraph) 기법을 통해 케로신의 대체 물질인 데칸/메틸사이클로헥산 혼합연료를 사용하는 단일 제트(jet)를 초임계 환경으로 분사하여 제트의 거동을 가시화하였다. T<SUB>r</SUB> = 0.484 인 연료 제트의 분사 차압 ΔP는 0.5 ㎫로 일정하게 유지하였고 혼합연료의 임계점 이상에서 실험을 진행하였으며 챔버 내부 환산온도 T<SUB>r</SUB>(=T/T<SUB>c</SUB>)를 1.00~1.23, 환산압력 P<SUB>r</SUB>(=P/P<SUB>c</SUB>)을 1.00, 1.38로 변화하여 실험결과를 분석하였다. 초임계 환경으로 분사되는 제트의 밀도감소 지표로써 후처리된 제트 이미지의 밝기 강도를 챔버 내부 온도와 압력을 변화시켜 관찰하였다. 챔버 내부 온도가 상승할 때 제트의 밝기 강도 감소 폭이 커지는 것을 확인하였으며, 동일 온도일 때 챔버 내부 압력이 높을 경우 제트의 밝기 강도 감소가 지연되는 것을 확인하였다. 챔버 내부 압력이 높을 경우 연료의 유사 임계온도(pseudocritical temperature)가 증가하고 연료 제트의 밀도감소에 필요한 온도가 상승하여 밝기 강도 변화가 지연되는 근거로 판단하였다. The single jet of decane/methylcyclohexane mixed fuel that is surrogate for kerosene was injected into supercritical environment and visualized using shadowgraph technique. The injection pressure drop of the fuel jet of T<SUB>r</SUB> = 0.484 was kept constant at 0.5 ㎫ and the experiment was conducted above the critical point of the mixed fuel, and the reduced temperatures of the chamber was changed from 1.00 to 1.23, and the reduced pressures was 1.00 and 1.38. As an index for reducing the density of jets sprayed into the supercritical environment, the brightness intensity of the post-processed jet image was observed with the internal temperature and pressure of the chamber. It was confirmed that the decrease in the brightness intensity of the jet when the temperature inside the chamber increased, and when the pressure inside the chamber was higher at the same temperature, the decrease in the brightness intensity of the jet was delayed. When the pressure inside the chamber is high, it is thought that the change in brightness intensity is delayed due to the increase in the pseudo-critical temperature of the fuel and the increase in the temperature required to reduce the density of the fuel jet.

실시간 PQ-RRT* 알고리즘을 이용한 유도 시스템 개발과 궤적 추종 제어기의 통합 설계 연구

안정우(Jung Woo An),김창주(Chang-Joo Kim) 제어로봇시스템학회 2022 제어·로봇·시스템학회 논문지 Vol.28 No.1

Herein, the integrated design process of guidance and control systems required for the design of autonomous flight systems for aircraft is discussed. The system can generate a trajectory using real-time path planning, re-plan the path, and accurately track the created trajectory. The real-time path planning is implemented using a rapidly-exploring random tree-based algorithm. Furthermore, the problems with the real-time rapidly-exploring random tree-based algorithm and possible solutions are discussed accordingly. The control system is implemented by incremental backstepping control, which ensures trajectory tracking performance across the entire flight envelope. To verify the series of processes, simulations are run using the high-fidelity Bo-105 model. The effectiveness of the real-time PQ-RRT* and path optimization algorithm proposed in this work is verified by the simulation results.

무인 항공기를 위한 실시간 경로 재계획 기법: RRT*와 LOSPO를 활용한 환경 변화 고려

안정우 ( Jung Woo An ),우지원 ( Ji Won Woo ),김현섭 ( Hyeon Seop Kim ),박상윤 ( Sang Yun Park ),남경래 ( Gyeon Rae Nam ) 한국항행학회 2023 韓國航行學會論文誌 Vol.27 No.4

무인 항공기는 다양한 분야에서 널리 활용되고 있으며, 실시간 경로 재계획은 이들 기기의 안전성과 효율성을 향상하는 핵심 요소이다. 본 논문에서는 RRT*와 LOSPO를 기반으로 한 실시간 경로 재계획 기법을 제안한다. 제안된 기법은 먼저 RRT* 알고리즘을 활용하여 초기 경로를 생성하고, LOSPO를 이용하여 경로를 최적화한다. 또한 최적화된 경로를 궤적으로 변경하여 실제 시간과 항공기의 동적한계를 고려할 수 있다. 이 과정에서 환경 변화와 충돌 위험을 실시간으로 감지하고, 필요한 경우 경로를 재계획함으로써 안전한 운행을 유지한다. 이 방법은 시뮬레이션을 통한 실험을 통해 검증되었다. 본 논문의 결과는 무인 항공기의 실시간 경로 재계획에 관한 연구에 중요한 기여할 것으로 기대한다. 또한 이 기법을 다양한 상황에 적용함으로써 무인 항공기의 안전성과 효율성을 향상시킬 수 있다. Unmanned aerial vehicles are widely used in various fields, and real-time path replanning is a critical factor in enhancing the safety and efficiency of these devices. In this paper, we propose a real-time path replanning technique based on RRT* and LOSPO. The proposed technique first generates an initial path using the RRT* algorithm and then optimizes the path using LOSPO. Additionally, the optimized path can be converted into a trajectory that considers actual time and the dynamic limits of the aircraft. In this process, environmental changes and collision risks are detected in real-time, and the path is replanned as needed to maintain safe operation. This method has been verified through simulation-based experiments. The results of this paper make a significant contribution to the research on real-time path replanning for UAVs, and by applying this technique to various situations, the safety and efficiency of UAVs can be improved.

임계환경에서 탄화수소 혼합물 이중충돌 제트의 상변화특성

안정우(Jeongwoo An),최명환(Myeung Hwan Choi),송주연(Juyeon Song),구자예(Jaye Koo) 한국항공우주학회 2021 한국항공우주학회 학술발표회 논문집 Vol.2021 No.7

아날로그 기반 위성 회수 및 표면 물질 분석

안정우(Jeong Woo Ahn),안이령(Yi Ryeong Ahn) 한국항공우주학회 2022 한국항공우주학회 학술발표회 논문집 Vol.2022 No.11