핸드폰

安貞煥 법조협회 1999 法曹 Vol.48 No.12

A Bending-Type Piezoelectric Energy Harvester with a Displacement-Amplifying Mechanism for Smart Highways

안정환,황원섭,조재용,정세영,송경주,홍성도,성태현,정신우,유홍희 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.3

Piezoelectric energy harvesting has gained attention owing to its effectiveness at harvesting electrical energy from various energy sources. Especially, with the increasing demand for smart highways, piezoelectric energy harvesting from road traffic has been increasingly studied. However, existing piezoelectric road-energy harvesters have limitations of low electrical output and low durability. A novel piezoelectric energy harvester was designed and fabricated to overcome these limitations. The proposed harvester had a maximum output power of 3.93 mW at a load resistance of 130 kΩ under an input displacement of 2.5 mm. The proposed harvester had 4.2 times more output power than the existing vibration-type road energy harvesters and was much less susceptible to destruction-in contrast to existing impact-type road-energy harvesters. The proposed road-energy harvester can be used as a power source for wireless sensor networks in smart highways.

시공간적으로 편중된 강우에 의한 홍수사상 수치모의 - 2017년 8월 17일 청계천 홍수사상을 대상으로

안정환,정창삼,Ahn, Jeonghwan,Jeong, Changsam 한국방재안전학회 2018 한국방재안전학회 논문집 Vol.11 No.2

본 연구는 2017년 8월 17일 청계천에서 발생한 시민고립사고의 원인을 규명하고, 고밀도 기상관측망의 관측자료를 이용하여 안전한 도시하천 관리 방안을 제시한 연구이다. SK 텔레콤 기지국에 설치된 고밀도 기상관측망인 SK techx와 상대적으로 공간적 밀도가 낮은 기상청 AWS의 사고 당일 강우자료를 도시유출모형에 적용하여 당시 상황을 모의하였다. 사고원인 중 하나로 가정한 CSO 관로 내 체수현상을 구현하여 수치모의한 결과, 기상청 AWS에서 계측된 강우량은 사고를 발생시키지 않았다. 하지만 실제 현상과 더 유사한 고밀도 기상관측망인 SK techx의 강우자료를 적용했을 때는 당일 발생한 사고와 유사한 결과가 나타났다. 이는 낮은 공간 밀도인 기상청 AWS는 청계천에서 일어나는 실제현상을 예측할 수 없고, 안전한 하천관리르 위해 고밀도 기상관측소가 필요하다는 것을 의미한다. 또한 CSO 관로 내 체수 유무를 독립변수로 수치 모의한 결과 비우당교의 CSO 관로 내 체수가 사고의 직접적인 원인으로 분석되었다. This study identifies the cause of the accident and presents a new concept for safe urban stream management by numerical simulating the flood event of Cheonggyecheon on August 17, 2017, using rain data measured through a dense weather observation network. In order to simulate water retention in the CSO channel listed as one of the causes of the accident, a reliable urban runoff model(XP-SWMM) was used which can simulate various channel conditions. Rainfall data measured through SK Techx using SK Telecom's cell phone station was used as rain data to simulate the event. The results of numerical simulations show that rainfall measured through AWSs of Korea Meteorological Administration did not cause an accident, but a similar accident occurred under conditions of rainfall measured in SK Techx, which could be estimated more similar to actual phenomena due to high spatial density. This means that the low spatial density rainfall data of AWSs cannot predict the actual phenomenon occurring in Cheonggyecheon and safe river management needs high spatial density weather stations. Also, the results of numerical simulation show that the residual water in the CSO channel directly contributed to the accident.

하악탈구의 고식적 정복법과 구강 외 정복법의 전향적 비교연구

안정환,정윤석,민영기,김기운,정지윤 대한응급의학회 2005 大韓應急醫學會誌 Vol.16 No.6

구 좌표계에서 삼차원 모델의 적응적 부호화 방법 (An Adaptive Method for 3D Model Coding Using The Spherical Coordinate System )

안정환,한만진,호요성 대한전자공학회 1998 대한전자공학회 학술대회 Vol.1998 No.1

중증 패혈증 및 패혈성 쇼크 환자에서 예측 인자로서의 시간으로 보정한 젖산 청소율의 유용성

안정환,민영기,정성희,이영주,최상천,정윤석 대한중환자의학회 2009 Acute and Critical Care Vol.24 No.3

Background: The lactate concentration should be used to examine the severity of sepsis or any state of shock. This study was conducted to investigate the prognostic power of the lactate clearance, as adjusted for time, between the survivors and nonsurvivors of patients with severe sepsis or septic shock. Methods: The study was performed on 67 patients over 16 years old and who were admitted to the intensive care unit (ICU) with severe sepsis or septic shock. They were divided into the survivors (n=37) and nonsurvivors (n=30). The blood lactate concentrations were assayed at intervals ranging from 8 to 24 hours and the APACHE III scoring was done daily for 2 weeks or until discharge or death. The lactate clearance, as adjusted for time, was defined using the following formula: [(the maximal lactate concentration-the normal lactate concentration)/the time to normalize the lactate concentration]×1,000. Results: There were no significant differences of age, gender and the length of the ICU stay between the survivors and non-survivors. There were significant difference of the time to measuring the maximal serum lactate concentration (3.2±12.3 hours vs. 28.8±64.6 hours, respectively; p=0.037), the lactate clearance, as adjusted for time (132.27±112.88 mol/L·hour vs. 59.67±72.60 mol/L·hour, respectively; p=0.002), the lactate clearance during 24 hours (46.0±26.3% vs. 22.6±45.6%, respectively; p=0.018) and the APACHE III score (67.6±22.7 vs. 83.9±21.6, respectively; p=0.005) between the survivors and non-survivors. The lactate clearance, as adjusted for time and the APACHE III score were the predictive factors for survival on the logistic regression analysis (odd ratio 0.987; p=0.028 vs. odd ratio 1.046; p=0.006). Conclusions: Lactate clearance, as adjusted for time, could be used as a prognostic index, as well as the APACHE III score, for patients with severe sepsis or septic shock.

통합예측을 이용한 삼차원 메쉬의 기하정보 부호화 알고리듬

안정환,호요성 대한전자공학회 2003 電子工學會論文誌-SP (Signal processing) Vol.40 No.3

The conventional parallelogram prediction uses only three previously traversed vertices in a single adjacent triangle; thus, the predicted vertex can be located at a biased position. Moreover, vortices on curved surfaces may not be predicted effectively since each parallelogram is assumed to lie on the same plane. In order to improve the prediction performance, we use all the neighboring vertices that precede the current vertex. After we order vortices using a vertex layer traversal algorithm, we estimate the current vertex position based on observations of the previously coded vertex positions in the layer traversal order. The difference between the original and the predicted vertex coordinate values is encoded by a uniform quantizer and an entropy coder. The proposed scheme demonstrates improved coding efficiency for various VRML test data. MPEG-4 삼차원 메쉬 모델 압축(3DMC) 표준에서 사용되는 평행사변형예측 방법은 예측하고자 하는 꼭지점이 인접한 꼭지점들과 같은 평면상에 있다고 가정하여 하나의 삼각형 내에 있는 인접한 세 개의 꼭지점 좌표 값만을 이용하므로 예측 효율이 좋지 않다. 본 논문에서는 삼각형 주변의 꼭지점 좌표값과 인접하는 삼각형 사이의 사잇각을 고려한 통합예측을 이용하여 삼차원 메쉬 모델의 기하정보를 부호화하는 방법을 제안한다. 우선 제안한 꼭지점 계층탐색 방법으로 위상학적으로 거리가 가까운 점들을 탐색하여 정렬된 값들의 기하학적 상관도를 높이고, 정렬된 삼차원 메쉬의 꼭지점 순서에 따라 주변의 꼭지점 값들을 이용하여 현재 꼭지점 값을 예측한다. 본 논문에서 제안한 통합예측 방법은 다양한 VRML 포맷의 테스트 모델에 대해서 기존의 MPEG-4 3DMC의 평행사변형예측 방법보다 우수한 성능을 보인다.

모후산에 올라

安貞煥 법조협회 1996 法曹 Vol.45 No.10

동학농민 혁명기념관

안정환,신기복,이길환 현대건축사 1999 월간 CONCEPT Vol.- No.5

급속한 의식 변화를 초래한 급성 황화수소 중독 1례

안정환,정윤석,Ahn, Jung-Hwan,Jung, Yoon-Seok 대한임상독성학회 2004 대한임상독성학회지 Vol.2 No.2

Hydrogen sulfide is a colorless, and malodorous 'rotten eggs' gas that results from the decay of organic material. It is a byproduct of industry and agriculture. The mechanism of its toxicity is primarily related to inhibition of oxidative phosphorylation, which causes a decrease in available cellular energy. Because there is no rapid method of detection that is of clinical diagnostic use, management decisions must be made based on history, clinical presentation, and diagnostic tests that imply hydrogen sulfide's presence. Although there is some anecdotal evidence to suggest that the early use of hyperbaric oxygen is beneficial, supportive care remains the mainstay of therapy. We describe an occupational exposure to hydrogen sulfide gas in 51-year-old man. While cleaning the sewage of pigs. he became unconscious. When he arrived in the emergency department, he had irritability and confused mentality. The typical smell of rotten eggs on clothing and exhaled air were enough to be considered to be exposed to hydrogen sulfide. Hyperbaric oxygen therapy was performed. He had a recovery to normal function.