서울시 도로노면하부 공동발생 메카니즘규명에 관한 사례연구

임도형,채휘영,최연우,최현 대한지질공학회 2017 대한지질공학회 학술발표회논문집 Vol.2017 No.1

Stress Analysis of Two-Dimensional Cellular Materials with Thick Cell Struts

임도형,김한성,김영호,김윤혁,S.T.S Al-Hassani 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.5

Finite element analyses (FEA) were performed to thoroughly validate the collapse criteria of cellular materials presented in our previous companion paper. The maximum stress (von-Mises stress) on the cell strut surface and the plastic collapse stress were computed for two-dimensional (2D) cellular materials with thick cell struts. The results from the FEA were compared with those from theoretical criteria of authors. The FEA results were in good agreement with the theoretical results. The results indicate that when bending moment, axial and shear forces are considered, the maximum stress on the strut surface gives significantly different values in the tensile and compressive parts of the cell wall as well as in the two loading directions. Therefore, for the initial yielding of ductile cellular materials and the fracture of brittle cellular materials, in which the maximum stress on the strut surface is evaluated, it is necessary to consider not only the bending moment but also axial and shear forces. In addition, this study shows that for regular cellular materials with the identical strut geometry for all struts, the initial yielding and the plastic collapse under a biaxial state of stress occur not only in the inclined cell struts but also in the vertical struts. These FEA results support the theoretical conclusion of our previous companion paper that the anisotropic 2D cellular material has a truncated yield surface not only on the compressive quadrant but also on the tensile quadrant.

초음파 응답특성 분석에 의한 위장 경화 진단시스템의 설계

임도형,김은근,이균정,박원필,김한성,신태민,최서형,이용흠,Lim, Do-Hyung,Kim, Eun-Geun,Lee, Gyoun-Jung,Park, Won-Pil,Kim, Han-Sung,Shin, Tae-Min,Choi, Seo-Hyung,Lee, Yong-Heum 대한의용생체공학회 2007 의공학회지 Vol.28 No.2

Functional gastrointestinal disorders affect millions of people of all age regardless of race and sex. There are, however, rare diagnostic methods for the functional gastrointestinal disorders because functional disorders show no evidence of organic and physical causes. Our research group identified recently that the gastrointestinal tract well in the patients with the functional gastrointestinal disorders becomes more rigid than healthy people when palpating the abdominal regions overlaying the gastrointestinal tract. The aim is, therefore, to develop a diagnostic method for the functional gastrointestinal disorders based on quantitative measurement of the rigidity of the gastrointestinal tract well using ultrasound technique. For this purpose, a preliminary ultrasound diagnostic system was developed and verified through phantom tests. The system consisted of transmitter, ultrasonic transducer, receiver, TGC, and CPLD, and verified via a phantom test. For the phantom test, ten soft-tissue specimens were harvested from porcine. Five of them were then treated chemically to mimic a rigid condition of gastrointestinal tract well, which was induced by functional gastrointestinal disorders. Additionally, the specimens were tested mechanically to identify if the mimic was reasonable. The customized ultrasound system was finally verified through application to human subjects with/without functional gastrointestinal disorders(Normal and Patient Groups). It was identified from the mechanical test that the chemically treated specimens were more rigid than normalspecimen. This finding was favorably compared with the result obtained from the phantom test. The phantom test also showed that ultrasound system well described the specimen geometric characteristics and detected an alteration in the specimens. The maximum amplitude of the ultrasonic reflective signal in the rigid specimens $(0.2{\pm}0.1Vp-p)$ at the interface between the fat and muscle layers was explicitly higher than that in the normal specimens $(0.1{\pm}0.0Vp-p)$ (p<0.05). Clinical tests using our customized ultrasound system for human subject showed that the maximum amplitudes of the ultrasonic reflective signals nea. to the gastrointestinal tract well for the patient group$(2.6{\pm}0.3Vp-p)$ were generally higher than those in normal group$(0.1{\pm}0.2Vp-p)$ (p<0.05). These results suggest that newly designed diagnostic system based on ultrasound technique may diagnose enough the functional gastrointestinal disorders.

유한 요소 해석을 이용한 고주파 간 종양 절제술의 입력 파형 최적화를 위한 연구

임도형,남궁범석,이태우,최진승,탁계래,김한성,Lim, Do-Hyung,NamGung, Bum-Seok,Lee, Tae-Woo,Choi, Jin-Seung,Tack, Gye-Rae,Kim, Han-Sung 대한의용생체공학회 2007 의공학회지 Vol.28 No.2

Hepatocellular carcinoma is significant worldwide public health problem with an estimated annually mortality of 1,000,000 people. Radiofrequency (RF) ablation is an interventional technique that in recent years has come to be used for treatment of the hepatocellualr carcinoma, by destructing tumor tissues in high temperatures. Numerous studies have been attempted to prove excellence of RF ablation and to improve its efficiency by various methods. However, the attempts are sometimes paradox to advantages of a minimum invasive characteristic and an operative simplicity in RF ablation. The aim of the current study is, therefore, to suggest an improved RF ablation technique by identifying an optimum RF pattern, which is one of important factors capable of controlling the extent of high temperature region in lossless of the advantages of RF ablation. Three-dimensional finite element (FE) model was developed and validated comparing with the results reported by literature. Four representative Rf patterns (sine, square, exponential, and simulated RF waves), which were corresponding to currents fed during simulated RF ablation, were investigated. Following parameters for each RF pattern were analyzed to identify which is the most optimum in eliminating effectively tumor tissues. 1) maximum temperature, 2) a degree of alteration of maximum temperature in a constant time range (30-40 second), 3) a domain of temperature over $47^{\circ}C$ isothermal temperature (IT), and 4) a domain inducing over 63% cell damage. Here, heat transfer characteristics within the tissues were determined by Bioheat Governing Equation. Developed FE model showed 90-95% accuracy approximately in prediction of maximum temperature and domain of interests achieved during RF ablation. Maximum temperatures for sine, square, exponential, and simulated RF waves were $69.0^{\circ}C,\;66.9^{\circ}C,\;65.4^{\circ}C,\;and\;51.8^{\circ}C$, respectively. While the maximum temperatures were decreased in the constant time range, average time intervals for sine, square, exponential, and simulated RE waves were $0.49{\pm}0.14,\;1.00{\pm}0.00,\;1.65{\pm}0.02,\;and\;1.66{\pm}0.02$ seconds, respectively. Average magnitudes of the decreased maximum temperatures in the time range were $0.45{\pm}0.15^{\circ}C$ for sine wave, $1.93{\pm}0.02^{\circ}C$ for square wave, $2.94{\pm}0.05^{\circ}C$ for exponential wave, and $1.53{\pm}0.06^{\circ}C$ for simulated RF wave. Volumes of temperature domain over $47^{\circ}C$ IT for sine, square, exponential, and simulated RF waves were 1480mm3, 1440mm3, 1380mm3, and 395mm3, respectively. Volumes inducing over 63% cell damage for sine, square, exponential, and simulated RF waves were 114mm3, 62mm3, 17mm3, and 0mm3, respectively. These results support that applying sine wave during RF ablation may be generally the most optimum in destructing effectively tumor tissues, compared with other RF patterns.

[특집] 자율운항 레저보트 기술 동향

임도형 대한조선학회 2023 大韓造船學會誌 Vol.60 No.2

발전설비 상태진단을 위한 주기 성능시험 제안

임도형,Im, Do-Hyeong 한국플랜트학회 2010 플랜트 저널 Vol.6 No.2

합성수지 화학반응 발화

임도형,박규석,이대혁 한국화재조사학회 2013 한국화재조사학회 학술대회 Vol.2013 No.1

Pulmonary Complications After Hematopoietic Stem Cell Transplantation

임도형,이지연,Hong Ghi Lee,박병배,백경란,오원섭,Sang Hoon Ji,이세훈,박준오,김기현,김원석,정철원,박영석,Young Hyuck Im,강원기,박근칠 대한의학회 2006 Journal of Korean medical science Vol.21 No.3

Despite advanced effective prophylaxes, pulmonary complications still occur in a high proportion of all hematopoietic stem cell recipients, accounting for considerable morbidity and mortality. The aim of our study was to describe the causes, incidences and mortality rates secondary to pulmonary complications and risk factors of such complications following hematopoietic stem cell transplantation (HSCT). We reviewed the medical records of 287 patients who underwent either autologous or allogeneic HSCT for hematologic disorders from February 1996 to October 2003 at Samsung Medical Center (134 autografts, 153 allografts). The timing of pulmonary complica-tions was divided into pre-engraftment, early and late period. The spectrum of pul-monary complications included infectious and non-infectious conditions. 73 of the 287 patients (25.4%) developed pulmonary complications. Among these patients, 40 (54.8%) and 29 (39.7%) had infectious and non-infectious conditions, respectively. The overall mortality rate from pulmonary complications was 28.8%. Allogeneic trans-plant, grade II-IV acute graft-versus-host disease (GVHD) and extensive chronic GVHD were the risk factors with statistical significance for pulmonary complications after HSCT. The mortality rates from pulmonary complications following HSCT were high, especially those of viral and fungal pneumonia, diffuse alveolar hemorrhage and idiopathic pneumonia syndrome.

N/A

임도형,이성재,탁계례,김승수,신태진,신규철,신정욱 대한기계학회 1999 대한기계학회 춘추학술대회 Vol.- No.-

신경망을 사용한 매도/매수 주식 종목 선정

임도형,이일병 한국경영과학회 2000 한국경영과학회 학술대회논문집 Vol.- No.1

주가는 시계열 데이터의 일종므로 많은 변수들이 주가의 변동에 영향을 미친다. 그러나몇멸 개의 어떠한 변수가, 이렇게 영향물 미치는 지 정확히 알려져 있지 않다. 그렇기 때문에 주가를 예측하는 것은 쉽지 않으며 단지 등락을 예측하는 것 조차도 쉽지 않다. 본 논문에서는 주가를 신호와 잡음이 혼합된 것으로 가점하고 그 특성을 고려하여, 전 종목에 대한 등락물 예측하지 않고, 예측율이 높은 종목물 선정하는 것을 목표로 하였다 MLP를 BP로 학습시켰으면 밉력으로는 28개의 주가분석 지표값이 사용되었다. 여러 예측 기간므로 실험하몄으며, 예측기간이 60일일 때 77.1%의 예측뮬물 보였고 선정된 좀목의 등락 예측물은 88%였다.