치과 임플란트용 골융합 측정기의 설계 및 평가

이주희,김창일,백종후,조정호,전명표,정영훈,이영진,이정배,이승대,Lee, Joo-Hee,Kim, Chang-Il,Paik, Jong-Hoo,Cho, Jeong-Ho,Chun, Myoung-Pyo,Jeong, Young-Hun,Lee, Young-Jin,Lee, Jeong-Bae,Lee, Seung-Dae 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.3

The osseointegration of dental implant is influenced by many factors such as surface geometry, loading and the amount of bone. Thus, stability of the dental implant should be checked periodically. In order to test the stability of dental implant by using resonance frequency analysis, we designed a structure of transducers and fabricated a piezoelectric devices. Using finite element analysis, the thickness and length of piezoelectric device and transducers were tailorized and the optimized frequency of 10 kHz was obtained. The resonance frequency from simulation analysis and evaluation was estimated to be similar as 10 kHz. The osseointegration was further enhanced with increasing frequency from the evaluation result of the finite element analysis.

치과용 초음파 골수술기 설계 및 평가

이주희,오정민,홍연우,김세기,백종후,이영진,이정배,이승대,Lee, Joo-Hee,Oh, Jung-Min,Hong, Younwoo,Kim, Seiki,Paik, Jonghoo,Lee, Young-Jin,Lee, Jeong-Bae,Lee, Seung-Dae 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.12

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

Flow and smoke behavior of a longitudinal ventilation tunnel with various velocities using computational fluid dynamics

이주희,권영진,김동은,Lee, J.H.,Kwon, Y.J.,Kim, D.E. Korean Tunnelling and Underground Space Associatio 2014 한국터널지하공간학회논문집 Vol.16 No.1

터널내의 연기거동 및 대피안전성을 평가하기 위하여 수치해석을 수행하였다. 본 연구의 목적은 최근 더욱 길어지고 있는 장대터널의 화재로 인한 연기 및 온도 분포와 안전성을 평가할 수 있는 수치적 방법을 구현하는데 있다. 계산에 사용되는 컴퓨터자원을 최소화하기 위하여 모델로 선정한 터널의 전체길이인 3 km을 사용하는 대신 여러 개의 대피터널이 포함되는 1.5 km만을 해석영역으로 사용하였다. 터널내의 연기거동에 의한 대피자의 안전성을 평가하기 위하여 연기의 밀도에 의한 기시도와 바닥으로부터의 높이를 고려한 SE (smoke environment)값을 사용하였다. 공기 중에 포함된 연기의 밀도는 3차원 전산유체역학을 통하여 구하였다. 이러한 연기 거동에 영향을 미치는 온도분포를 정확하게 모사하기 위하여 터널 벽면을 단열 혹은 일정한 열유속(heat flux) 가정을 사용하는 대신 1차원 열전도(heat conduction)방정식을 이용하여 터널벽면의 온도를 계산하였다. 대피터널간의 거리가 가까울수록 대피자의 안전성은 높아지겠지만 상대적으로 건설비용이 증가하게 된다. 본 연구에서 대피터널의 길이는 250 m로 하였으며 화재 시 제연팬의 운전 조건을 3가지 (팬이 가동되지 않는 조건, 임계풍속이하조건, 임계풍속이상조건)로 나누어 연기의 거동과 온도분포를 고찰하였다. 그리고 화재가 발생한 시간부터 플래쉬오버가 발생한 시간까지의 연기의 거동과 대피자의 상황을 SE를 이용하여 고찰하였다. A numerical analysis on the smoke behavior and evacuee safety has been performed with computational fluid dynamics. The purpose of this study is to build computational processes for an evacuation and prevention of a fire disaster of a 3 km-length tunnel in Korea. To save computational cost, 1.5 km of the tunnel that can include a few cross-passing tunnels is considered. We are going to assess the fire safety in a road tunnel according to the smoke level, which consists of the smoke density and the height from the floor. The smoke density is obtained in detail from three-dimensional unsteady CFD analysis. To obtain proper temperature distributions on the tunnel wall, one-dimensional conduction equation is considered instead of an adiabatic wall boundary or a constant heat flux. The tunnel considered in this study equips the cross passing tunnels for evacuees every 250 m. The distance is critical in both safety and economy. The more cross passing tunnels, the more safe but the more expensive. Three different jet fan operations can be considered in this study; under- and over-critical velocities for normal traffic condition and 0-velocoty operation for the traffic congestion. The SE (smoke environment) level maps show a smoke environment and an evacuating behavior every moment.

통영지역 해녀의 식습관 및 영양소섭취 실태조사

이주희,김찬,Lee, Joo-Hee,Kim, Chan 대한지역사회영양학회 2002 대한지역사회영양학회지 Vol.7 No.6

The purpose of this study was to investigate the nutritional intake and dietary habits of women divers in Tongyoung area and to support the guideline for the improvement of their dietary life style by a validation of a Computerized Semi-quantitative Food Frequency Questionaire. Compared to the women at Jeju Island, the Tongyoung divers showed similar heights (154.6 $\pm$ 0.8 cm), weights (53.5 $\pm$ 1.0 kg) and BMIs (23.3 $\pm$0.4) , but they showed especially high levels of body fat (33.8 $\pm$ 0.8) . Their dietary habits showed they usually skipped lunch, but ate too much food at once, which may represent the dietary habits shown by obese people. Over 40% of the divers were taking some nutritious food or complementary food for health, without realizing the efficacy of these foods. The analysis of nutritional intake showed that all of average daily nutrients intakes of those below 50 years were higher than those of the Korean RDA. In the case of those above 50 years, it was shown that the average daily nutrients intakes were also higher than those of the Korean RDA except for energy (94.5%) and calcium (82.1%) . However, some individual divers showed lower nutrients intakes than 75% of RDA for calcium, iron, Vitamin A and Vitamin B$_2$. Also, excessive intakes of phosphorous and sodium could be a dietary problem. There was no correlation between BMI or percentage of body fat and energy, CHO, protein or fat. These results can provide the nutritional information for this special community, women divers, to improve their health.

NASA 워크숍 및 해외 착륙임무에 기반한 달 착륙 후보 지역과 임무에 대한 고찰

이주희,류동영,Lee, Joohee,Rew, Dong-Young 한국우주과학회 2021 우주기술과 응용 Vol.1 No.3

우리나라는 2022년 8월 시험용 달 궤도선을 처음으로 달에 보낼 계획이다. 그리고 제3차 우주개발 진흥 기본계획을 통해서 밝힌 바에 따르면 이후 2030년 이전까지는 달 착륙선을 달에 보낸다는 계획이다. 달 착륙지역 선정에는 착륙선의 임무에 따라 적합한 착륙 지역이 달라질 수 있으며, 따라서 성공적인 달 탐사임무 설계를 위해서는 달 착륙지역에 대한 사전 연구가 반드시 필요하다. 본 논문에서는 2018년 NASA 워크숍에서 제안한 주요 달 착륙 후보지역에 대한 자료를 바탕으로 NASA의 MoonTrek을 이용하여 14개 제안 지역중 주요 지역의 특성을 분석하였다. 그리고 이런 지역이 향후 어떠한 달 착륙 임무에 적합한지 알아보았다. 또한 최근 달 착륙 국가들의 달 착륙 지역과 아르테미스(Artemis) 계획을 통해 달 남극의 중요성에 대해서도 알아 보았다. Korea plans to send a pathfinder lunar orbiter to the Moon for the first time in August 2022. And according to the 3rd Basic Plan for Space Development Promotion, the plan is to send a lunar lander to the Moon before 2030. The selection of the lunar landing area can be varied depending on the lunar lander's mission, therefore preliminary research on the lunar landing sites is essential for a successful lunar exploration mission design. This paper analyzed the characteristics of major regions among 14 proposed regions using NASA's MoonTrek based on the data on the candidate areas for the major moon landing proposed sites by the NASA workshop in 2018. And we looked into what kind of future moon landing missions are suitable for these areas. We also looked at the importance of lunar Antarctica area through the recent lunar landing areas of Moon landing countries and Artemis plan.

X-ray 영상에서 SegNet을 이용한 폐결핵 자동검출 시스템의 유용성 평가

이주희,안현수,최동혁,태기식,Lee, J.H.,Ahn, H.S.,Choi, D.H.,Tae, Ki Sik 대한의용생체공학회 2017 의공학회지 Vol.38 No.1

Testing TB in chest X-ray images is a typical method to diagnose presence and magnitude of PTB lesion. However, the method has limitation due to inter-reader variability. Therefore, it is essential to overcome this drawback with automatic interpretation. In this study, we propose a novel method for detection of PTB using SegNet, which is a deep learning architecture for semantic pixel wise image labelling. SegNet is composed of a stack of encoders followed by a corresponding decoder stack which feeds into a soft-max classification layer. We modified parameters of SegNet to change the number of classes from 12 to 2 (TB or none-TB) and applied the architecture to automatically interpret chest radiographs. 552 chest X-ray images, provided by The Korean Institute of Tuberculosis, used for training and test and we constructed a receiver operating characteristic (ROC) curve. As a consequence, the area under the curve (AUC) was 90.4% (95% CI:[85.1, 95.7]) with a classification accuracy of 84.3%. A sensitivity was 85.7% and specificity was 82.8% on 431 training images (TB 172, none-TB 259) and 121 test images (TB 63, none-TB 58). This results show that detecting PTB using SegNet is comparable to other PTB detection methods.

성인 심장수술 후 중환자실에 입실한 환자의 계획된 발관 후 비계획적 기관 재삽관 위험요인과 임상결과

이주희,최혜란,Lee, Ju-Hee,Choi, Hye-Ran 한국중환자간호학회 2022 중환자간호학회지 Vol.15 No.3

Purpose : This study aimed to identify risk factors for unplanned reintubation after planned extubation and to analyze the clinical outcomes in patients admitted to the intensive care unit after cardiac surgery. Methods : The study examined patients who underwent intubation and planned extubation admitted to the intensive care unit after cardiac surgery between January 1, 2017, and December 31, 2021. The reintubation group comprised 58 patients underwent unplanned reintubation within 7 days of planned extubation. The maintenance group comprised 116 patients who did not undergo reintubation and were matched with the reintubation group using the rational for matching criteria. Data were collected retrospectively from electronic medical records. We used the independent t-test, Mann-Whitney U test, 𝑥²-test, Fisher's exact test, and logistic regression analysis with SPSS/WIN 27.0. Results : The multivariate logistic regression analysis demonstrated that albumin (odds ratio [OR]=0.38, 95% confidence interval [CI]=0.20-0.72), surgery time (OR=1.54, 95% CI=1.20-1.97), PaO₂ before extubation (OR=0.85 per 10 mmHg, 95% CI=0.75-0.97), postoperative arrhythmia (OR=2.82, 95% CI=1.22-6.51), reoperation due to bleeding (OR=4.65, 95% CI=1.27-17.07), and postoperative acute renal failure (OR=2.97, 95% CI=1.09-8.04) were risk factors for unplanned reintubation. The reintubation group had a higher in-hospital mortality rate (𝑥²=33.74, p<.001), longer intensive care unit stay (Z=-7.81, p<.001), and longer hospital stay than the maintenance group (Z=-8.29, p<.001). Conclusion : These results identified risk factors and clinical outcomes of unplanned reintubation after planned extubation after cardiac surgery. These findings should be considered when developing and managing an intervention program to prevent and reduce the incidence of unplanned reintubation.

레이저 - 의학분야에서의 이용과 전망

이주희,Lee, Ju-Hui 한국과학기술단체총연합회 1985 과학과 기술 Vol.18 No.3

환경해설기법을 적용한 탐방객 안내소의 조성

이주희,Lee, Ju-Hui 한국자연공원협회 1993 한국자연공원 Vol.59 No.-

수의사의 일기-도축장, 천국보다 낯선 곳

이주희,Lee, Ju-Hui 대한수의사회 2007 대한수의사회지 Vol.43 No.2