전산수치해석을 이용한 일방향 철근콘크리트 부재의 폭발 실험결과 분석

지훈,Ji, Hun 한국군사과학기술학회 2016 한국군사과학기술학회지 Vol.19 No.4

A few blast experiments are conducted to investigate the behavior of one-way reinforced concrete(RC) slabs under blast loading. Reflected blast characteristics as well as displacements and damage patterns of RC slabs are measured. Numerical models are also established in the software ANSYS AUTODYN to reproduce the experiments on RC slabs. The numerical models are distinguished from each other by different boundary conditions at the edges of RC slabs, which are assumed to reproduce displacements and damage patterns resulted from the experiments. The boundary condition of the experimental tests is estimated from the numerical simulation results. From the numerical simulation results, the boundary condition should be improved in order to measure the accurate maximum displacement in the experimental tests.

췌장 지방종 : 1례보고

지훈,조휘율,김영주,홍인수,김명순,성기준,Ji, Hoon,Cho, Whi-Youl,Kim, Young-Ju,Hong, In-Soo,Kim, Myung-Soon,Sung, Ki-Joon 대한영상의학회 1992 대한영상의학회지 Vol.28 No.5

An echogenic lobulated round mass in the head of pancreas was found during abdominal ultrasonography for routine on a 34 vear-old man. CT and MRI showed characteristic findings of lipoma. Clinical followup confirmed intrapnacreatic lipoma, which had been reported only once proviously. This lesion should be added to list of benign connective tissue tumor of the pancreas.

99mTc-PMT 영상을 이용한 간암의 특이적 진단

지훈,유형식,이도연 대한핵의학회 1988 핵의학 분자영상 Vol.22 No.1

일축압축시험을 통한 황등화강암의 손상기준 결정

지훈,장현식,장보안 대한지질학회 2009 대한지질학회 학술대회 Vol.2009 No.

내부폭발 시 철근콘크리트 구조물 거동에 대한 전산수치해석과 실험적 검증

지훈,문세훈,정진웅,성승훈,유양선,Ji, Hun,Moon, Sei-Hoon,Chong, Jin-Wung,Sung, Seung-Hun,You, Yang-Sun 한국시뮬레이션학회 2018 한국시뮬레이션학회 논문지 Vol.27 No.1

실험과 유한요소코드를 이용한 수치해석은 폭발 하중에 의한 구조거동을 이해하는 유용한 방법이다. 그러나 내부폭발에 의한 철근콘크리트 구조물 거동에 대한 유한요소해석 결과와 실험적 검증에 대한 자료는 극히 드물다. 이 논문에서는 내부폭발에 의한 철근콘크리트 구조물 거동을 수치해석과 실험적으로 연구하였다. 방 하나짜리 축소형 콘크리트 내력벽 건물 중심에서 TNT가 기폭되는 상황을 고려하였다. 내부 폭풍압 분포와 철근콘크리트 벽 거동 분석은 유한요소 해석 코드인 ANSYS AUTODYN을 사용하였다. 수치해석과 실험을 비교한 결과 방 내부 세 곳에서 측정한 폭풍압과 두 벽 중심의 변위, 네 벽의 파손형태가 유사하게 나타났다. 또한 내부폭발 시 구조부재 거동에 대한 수치해석의 타당성과 정당성을 구조적 피해평가 측면에서 논의한 결과, 해석과 실험에서 같은 파손으로 평가되었다. Field experiments as well as numerical analyses with finite element analysis codes are two valuable and complemental ways to understand the structural response under explosive blast load. However, there seems to be only limited information available about finite element analysis and experimental validation on the response of structural components under internal explosions. For complementary use of the two ways, the numerical analyses should be validated with field experiments by comparing their results. In this paper, a small-scaled reinforced concrete building with a room is employed for experimental investigations. An amount of TNT is detonated at the center of the room. Pressure at three different sites in the room, displacement of centers of two walls, and damage patterns of four walls are measured and compared to results from numerical analyses. The experimental results are much similar to the numerical analyses results. The finite element analysis code ANSYS AUTODYN is employed to numerically analyze both pressure distribution inside the room and response of walls subjected to blast pressure. The feasibility and validity of the numerical analysis on the reponses of structural components under internal explosions are discussed in terms of structural damage assessment, and evaluated as the same damage in the analysis and the experiments.

동맥류성 골낭증

지훈,서진석,Ji, Hoon,Suh, Jin-Suck 대한영상의학회 1987 대한영상의학회지 Vol.23 No.6

In 4 patients with aneurysmal bone csyts, radiologic findings of their conventional x-rays, 99mTc-MDP bone scans and CT scans were reviewed. On CT scans, 3 patients revealed so called "the fluid-fluid levels." It must be one of the specific findings which is able to diagnose the ABC. When we performed the ultrasongraphy in a patient with the balooig out lesion on right ilium. multiple horizontal echogenic lines were observed in the supine and decubitus position. It could be interpretated as a identicla finding to the fluid-fluid levels on CT. Therefore ultrasonography is also one of the specific diagnostic tools to detect the ABC. Transcatheter embolizaton was beneficial in reducing operation time and blood loss, and in supplying clear operation field.ion field.

생후 63일 된 영아에 발생한 황색육아종성 신우신염

지훈,이경상,오기근,홍창호,최형기,정우희,양문희,Ji, Hoon,Lee, Kyoung-Sang,Oh, Ki-Keun,Hong, Chang-Ho,Choi, Hyoung-Ki,Jung, Woo-Hee,Yang, Moon-Hee 대한영상의학회 1987 대한영상의학회지 Vol.23 No.2

Xanthogrnulomatous pyelonephritis is an uncommon disease, which is usually seen in middle aged women and is quite rare in children. Authors report a case of focal xanthogranulomatous pyelonephritis in a 63 day old boy who had a partly functioning right kidney on IVP. On ultrasonogram and CT scan, well demarcated multiple septated cystic mass with enhancing rim was noted in right pole, suggesting as multilocular cyst or cystic Wilms'tumor rath than chronic infection at that time, which was proven as xanthogranulomatous pyelonephritis. Here a case of xanthogranulomatous pyelonephritis in infant is presented with review of literature.

전산수치해석을 이용한 일방향 철근콘크리트 슬래브의 연속폭발 누적피해 평가기법 연구

지훈,성승훈,정진웅,최윤수,Ji, Hun,Sung, Seung-Hun,Chong, Jin Wung,Choi, Yoon Soo 한국시뮬레이션학회 2020 한국시뮬레이션학회 논문지 Vol.29 No.2

본 연구에서는 해석적 방법을 이용하여 연속폭발 하중을 받는 구조물의 거동을 분석하였다. 구조물은 양단이 고정된 축소형 일방향 철근콘크리트 슬래브를 사용하였으며, 유한요소 해석을 위해서 상용 소프트웨어인 LS-DYNA를 사용하였다. 누적피해 평가를 위한 해석을 수행하기에 앞서, 해석 모델의 검증을 위해 일방향 철근콘크리트 슬래브의 단일폭발 실험을 수행하였다. 누적피해 해석에서는 이상적인 연속폭발 하중이 구조물에 적용되고, 최대변위를 기준으로 누적 피해평가를 수행하였다. 해석 결과로부터, 연속폭발 하중을 받는 철근콘크리트 슬래브의 최대 누적변위는 위험한 피해 한계까지 일정하게 증가하는 경향을 보였다. This study numerically investigated a structural behavior subjected to consecutive explosions. To this end, a small scale one-way reinforced slab (RC) with fixed-fixed boundary condition was considered as the target structure, and a commercial software, LS-DYNA, was utilized for finite element (FE) analysis. Prior to performing FE analysis, preliminary tests were carried out to verification of a computational model for the one-way RC slab. In the numerical simulation, identical blast loads were consecutively applied to the structure, and cumulative damage assessment were carried out based on its maximum dynamic displacements. As a result of the numerical simulation, it was found that maximum displacements considering permanent deformation due to a prior explosion were almost linearly increased in every explosion until the hazardous damage threshold.

발 움직임 검출을 통한 로봇 팔 제어에 관한 연구

지훈(H. Ji),이동훈(D. H. Lee) 한국재활복지공학회 2015 재활복지공학회논문지 Vol.9 No.1

팔의 사용이 자유롭지 못한 장애인들을 위하여 발의 움직임 검출을 통하여 로봇 팔을 제어할 수 있는 시스템을 구현하였다. 발의 움직임에 대한 영상을 얻기 위하여 양쪽 발 앞에 두 대의 카메라를 설치하였으며, 획득된 영상에 대해 LabView 기반 Vision Assistant를 이용하여 다중 관심영역을 설정한 후, 좌/우영역내에서 검출된 좌/우, 상/하 엣지를 기반으로 발의 움직임을 검출하였다. 좌/우 두발의 영상으로부터 좌/우 엣지와 상/하 엣지 검출 수에 따라 6관절 로봇 팔을 제어할 수 있는 제어용 데이터를 시리얼 통신을 통해 전송한 후 로봇 팔을 발로 상/하, 좌/우 제어할 수 있는 시스템을 구현하였다. 실험 결과 0.5초 이내의 반응속도와 88% 이상의 동작 인식률을 얻을 수 있었다. The system for controlling the robotic arm through the foot motion detection was implemented for the disabled who not free to use of the arm. In order to get an image on foot movement, two cameras were setup in front of both foot. After defining multiple regions of interest by using LabView-based Vision Assistant from acquired images, we could detect foot movement based on left/right and up/down edge detection within the left/right image area. After transferring control data which was obtained according to left/right and up/down edge detection numbers from two foot images of left/right sides through serial communication, control system was implemented to control 6-joint robotic arm into up/down and left/right direction by foot. As a result of experiment, we was able to get within 0.5 second reaction time and operational recognition rate of more 88%.

메타 러닝과 방법론 연구 동향

지훈 ( Hoon Ji ),이연준 ( Yeon-joon Lee ) 한국정보처리학회 2023 한국정보처리학회 학술대회논문집 Vol.30 No.1