해부학적 기능을 고려한 환자맞춤형 근위대퇴골 모델의 파라메트릭 변형 방안

박병건(Byoung-keon Park),채제욱(Chae-jae Wook),김재정(Jay-jung Kim) (사)한국CDE학회 2011 한국CDE학회 논문집 Vol.16 No.6

The morphology of a bone is closely associated with its biomechanical response. Thus, much research has been focused on analyzing the effects of variation of bone morphology with subject-specific models. Subject-specific models, which are generally achieved from 3D imaging devices like CT and MRI, incorporate more of the detailed information that makes a model unique. Hence, it may predict individual responses more accurately. Despite these powerful characteristics, specific models are not easily parameterized to the extent possible with statistical models because of their morphologic complexities. Thus, it is still proven challenging to analyze morphologic variations of subject-specific models across changes due to aging or disease. The aim of this article is to propose a generic and robust parametric morphing method for a subject-specific bone structure. We demonstrate this by using the proposed method on a model of a human proximal femur. Automatic segmentation algorithms are also presented to parameterize the specific model efficiently. A total of 48 femur models were evaluated for defining morphing vector fields. Also, several anatomical and mechanical functions of femur were considered as morphing constraints, and the NURBS interpolating technique was applied in the method to guarantee the generality of our morphed results.

개인병사의 생존성 증대를 위한 생체신호 모니터링 기법의 설계 및 구현

이승열,박상훈,이춘우,김현준,채제욱,Lee, Seung-Youl,Park, Sang-Hoon,Lee, Choon-Woo,Kim, Hyun-Jun,Chae, Jae-Wook 한국군사과학기술학회 2013 한국군사과학기술학회지 Vol.16 No.6

Recently, personal health monitoring system using intelligent biosensors and equipments has been realized. This system can be adopted for soldier's biosignal monitoring system. In this paper, we propose a soldier biosignal monitoring system using personal biosensors, such as the ECG sensors and accelerometer.

은닉 마코프 모델을 이용한 심전도 QRS 검출 최적화에 관한 연구

김상민(Sang-Min Kim),이혁재(Hyeok-Jae Lee),민경진(Kyoung-Jin Min),김경섭(Kyeong-Seop Kim),곽휘권(Hwy-Kuen Kwak),고윤수(Yun-Soo Ko),채제욱(Je-Wook Chae),이정은(Jung-Eun Lee),이정환(Jeong-Whan Lee) 대한전기학회 2019 전기학회논문지 Vol.68 No.11

The heart is the body"s circulatory organ that supplies blood to the body. An electrocardiogram is the best means of measuring and diagnosing abnormal conduction of the heart muscle. Therefore, to diagnose patients suspected of heart disease, a Holter monitoring system measuring electrocardiography for 24 hours is used by doctors to examine and diagnose patients. However, diagnosing innumerable Holter data entails considerable effort by doctors directly. If QRS can be detected by an automated diagnostic system, many Holter data could be classified without diagnosing it by clinicians directly. In this paper, we tried to detect the QRS of electrocardiogram using the Hidden Markov Model. For objective verification, the onsets and offsets of QRS, which classified by the specialist, in the QT-database, were used as the reference labels. The Mexican Hat mother function was used for the wavelet transform. To study how to optimize the learning of hidden Markov models, the experiment was conducted by changing the batch size of the training data sets and the scale of the wavelet mother function. During the verification process, the mean and standard deviation of the difference between QRS onset and offset obtained from the test data sets through the hidden Markov model and the reference label classified by a specialist were used. As a result, the batch size was found to have the best performance using all 84 training data sets, and the scale of the mother function was found to have the best performance using scale j = 2, 3, 4. When the mean and standard deviation of QRS complexes detected from the hidden Markov model was -8.2822ms, ±5.821476ms(p=0.99818) onsets, respectively and -2.9588ms, ±6.5662ms(p=0.99838) offsets, respectively with 84 batch sizes and all three scale mother functions were trained, the results of onset, offset standard deviation were improved average about 22.1%, 30.9% respectively when compared with other algorithms using QT-Database

신장반사 해석 모델 및 진자 실험을 이용한 하지의 질량 관성모멘트 예측 방법

강문정(Moon Jeong Kang),조영남(Young Nam Jo),채제욱(Jae Wook Chae),유홍희(Hong Hee Yoo) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

It is important to predict mass moment of inertia of each segment for analyzing human motions. Analytical and experimental methods have been studied for predicting it. The former is methods calculating it by assuming the segment as uniform bar or using 3 dimensional images such as MRI, and the latter is a method predicting it from cadaver experiments. However, these methods oversimplify human segments or cost a lot of money and time. Moreover, the method using 3 dimensional images have been pointed out safety because subjects have to be exposed to radiation. Therefore, present study suggests safe and simple method that can reflect physical quality in vivo. We did pendulum tests dropping a leg relaxing and stretching in a sitting position without notice, and predict mass moment of inertia of the leg using the experimental results and stretch reflex model. The stretch reflex model consists of muscle properties and model parameters, and it can identify muscle activation by a stretch reflex from kinematics of a leg. The present studies set mass moment of inertia and model parameters as variables, and solve the optimization problem which minimizes the integrated error of knee angle from experiment and analysis to predict mass moment of inertia of a leg. Compared to results from the present study and previous study, we confirmed that suggested method is most efficient to predict the mass moment of inertia of human limb.

신장반사 해석 모델을 이용한 삼두근 반사 해석

강문정(Moon Jeong Kang),조영남(Young Nam Jo),채제욱(Jae Wook Chae),유홍희(Hong Hee Yoo) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.4-2

비미란성 위식도 역류질환의 진단에서 ZAP 분류의 유용성

김동희 ( Dong Hee Kim ),이풍렬 ( Poong Lyul Rhee ),조대현 ( Dae Hyun Cho ),채제욱 ( Jae Wook Chae ),김정환 ( Jeong Hwan Kim ),김지은 ( Jee Eun Kim ),손희정 ( Hee Jung Son ),김재준 ( Jae J. Kim ),백승운 ( Seung Woon Paik ),이종철 ( 대한소화기기능성질환·운동학회 2005 Journal of Neurogastroenterology and Motility (JNM Vol.11 No.2

목적: 위식도 경계부의 장상피화생은 식도선암의 발생과 연관이 있으며 Z선의 형태학적 모양에 따른 ZAP 분류는 위식도 역류질환을 가진 환자의 하부식도 상피의 장상피화생과 상관관계가 있다고 보고된 바 있다. 본 연구에서는 무증상 정상 성인과 위식도 역류증상을 호소하는 비미란성 위식도 역류질환군 및 미란성 위식도 역류질환군에서 ZAP 분류가 이들을 감별하는데 있어서 유용한지를 알아보고 역류증상의 정도와 ZAP 분류간의 상관관계를 알아보고자 하였다. 대상 및 방법: 2003년 10월부터 2004년 6월까지 위식도 역류증상을 주소로 삼성서울병원 소화기내과를 내원한 환자 50명과 역류증상을 보이지 않는 건강한 성인 23명을 대상으로 역류증상의 중증도, 빈도, 이환기간에 관한 설문과 내시경검사를 시행하였다. 위식도 역류질환 환자중 비미란성 위식도 역류질환군은 19명, 미란성 위식도 역류질환군은 31명이었다. 결과: 무증상 정상군, 비미란성 위식도 역류질환군, 미란성 위식도 역류질환군사이에 나이, 성별, 흡연, 음주력, 당뇨, 고혈압에서 각 군간에 유의한 차이는 보이지 않았다. ZAP 분류는 각군에서 통계적으로 유의한 차이를 보였다(p<0.05). 내시경적으로 역류성 식도염이 없는 환자에서 ZAP 분류가 양성인 경우 비미란성 위식도 역류질환(NERD)을 시사할 가능성이 무증상 정상군보다 3.66배 높았다. 위식도 역류증상이 있는 군 50명 중 ZAP 분류와 LA 분류는 다소 높은 양의 상관관계를 보였다(p<0.05). 역류증상의 중증도, 빈도, 이환기간과 ZAP 분류는 모두 유의한 상관관계를 보이지 않았다. 결론: ZAP 분류는 비미란성 위식도 역류질환과 미란성 위식도 역류질환사이에 유의한 차이를 보였으며 LA 분류와도 좋은 상관관계를 보였고 비미란성 위식도 역류질환을 진단하는데 정상인에 대한 우도비율도 높아 역류성 식도질환 진단에 사용할 수 있을 것으로 생각된다. Background/Aims: It has been documented that the Z-line appearance (the ZAP grade) was correlated with the prevalence of intestinal metaplasia. This study was performed to investigate whether there is any correlation between the ZAP grade and the severity of GERD, such as non-erosive reflux disease (NERD) and erosive reflux disease (ERD). Methods: Consecutive 50 patients with typical reflux symptoms (heartburn and acid regurgitation) and 23 asymptomatic healthy controls were enrolled in this study. The GERD group (n=50) was classified into 2 groups: ERD (n=31) and NERD (n=19). The symptom characteristics were collected by conducting face-to-face interviews with using a structured questionnaire. Endoscopy was performed to determine the ZAP grade and the LA classification. Results: There were significant differences in the ZAP grade among the controls, the NERD group, and the ERD group (p<0.05), although there was no significant difference in age, gender, body weight and smoking history among the three groups. Relatively high correlation was revealed between the ZAP grade and the LA classification (Spearman correlation factor: 0.445). The likelihood ratio to endoscopically diagnose NERD by the ZAP in the patient without reflux esophagitis was 3.66. There were no significant differences in the severity, duration and frequency of symptom according to the ZAP grade. Conclusions: The ZAP classification may give a clue to diagnosing NERD in the absence of erosive esophagitis, and it could be applied as a useful diagnostic tool for GERD. (Kor J Neurogastroenterol Motil 2005;11:97-103)

기능기반변형안 및 Computed muscle control 기술을 이용한 인체 동작 모사 및 예측을 위한 디지털 근골격모델의 개발

구본열(Koo, Bon-yeol),박병건(Park, Byoung-keon),박은주(Park, Eun-joo),채제욱(Chae, Jae-wook),김재정(Kim, Jay-jung) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7

본 연구는 선행 개발된 기능기반변형기술(이하 FBD)을 이용하여 선정된 대상의 대퇴골 형상을 제어하고, 변형된 대퇴골의 형상과 이로 인한 근육 부착점의 이동이 대상의 보행에 어떠한 영향을 미치는 지를 분석한다. 또한 분석된 골격 형상과 보행 패턴의 관계를 기반하여 특정 대상인의 보행 패턴을 가상의 환경에서 모사하고, 나아가 골격의 형상만으로 대상의 보행을 예측할 수 있는 방법을 제안한다. 제안된 방법은 FBD를 이용함으로 정밀한 근육 부착점 및 고관절 형상을 기반으로 하였기 때문에 기존의 보행 예측방안에 비해 보다 정확한 근육활성도 분석모델 및 보행 예측 모델을 얻을 수 있었다. 제안된 방안의 유효성을 평가하기 위해 실제 사람의 보행 패턴을 삼차원으로 측정한 데이터와 가상에서 모사된 보행을 비교, 평가하였다.

하지부 근육의 압축 특성을 고려한 진자 실험 해석 모델 개발

강문정(Moon Jeong Kang),박준홍(Jun Hong Park),채제욱(Jae Wook Chae),유홍희(Hong Hee Yoo) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.바이오공학 No.-

3-D Beam 요소 인체모델을 이용한 사격충격 구조해석

이세훈(Se-Hoon Lee),이영신(Young-Shin Lee),최영진(Young-Jin Choi),이재옥(Jae-Ok Lee),채제욱(Je-Wook Chae),최의중(Eui-Jung Choi) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

The rifle impact of human body is affected by the posture of human for rifling. The human model of shooting posture is defined by the action of shooter. The shooting impact of the rifle is transferred to the human model. In this study a finite element analysis has been performed in order to investigate the human body impact by shooting of rifle. The model(height 170 ㎝, weight 60 ㎏) is developed by finite element method using beam elements. The human body impulse is analyzed by the ANSYS 8.1 code. The human impact analysis of stand shooting posture, knee shooting posture and prone shooting posture is investigated. In this study, the rifle used for the impulse analysis is K2. The applied load for the simulation inputs is about 4 kN. As the results, the displacement and stress of human body is presented.

발열을 동반한 호중구감소증에서 Cefepime 단독투여와 Ceftazidime 및 Tobramycin 병합투여의 효능비교

정현욱,채제욱,강미라,양정채,문치숙,기현균,장현하,오원섭,김기현,백경란,이남용,송재훈 대한감염학회 2004 감염과 화학요법 Vol.36 No.6

목적 : 국내에서 발열을 동반한 호중구감소증이 있는 악성 종양환자에게 경험적 항생제로 베타락탐계 항생제와 아미노배당체의 병합요법의 사용이 일반적이다. Cefepime은 광범위 항균 작용을 가지고 있어, 그람 음성균 뿐만 아니라 그람 양성균에 대해서도 우수한 효과를 나타낸다. 재료 및 방법: 발열을 동반한 호중구감소증이 있는 악성 종양환자를 대상으로 무작위, 공개, 비교 연구를 시행하였다. 대상 환자를 무작위로 cefepime 단독요법군과 ceftazidime 및 tobramycin 병합요법군으로 나누어 투여하고 각각의 임상적 효능과 안전성을 비교하였다. 구강및 인후 점막염이 있는 환자에서 분리된 녹색 연쇄알 구균에 대한 항생제 내성 정도를 조사하였다. 결과 : 대상환자 89명 중 CA 투여군이 48예(53.9%), CT 투여군이 41예(46.1%)이었다. 발열의 유형별로 MDI는 18예(20.2%), CDI는 9예(10.1%), UF는 62예(69.7%)로 두 군 간에 차이가 없었다. CA 투여군과 CT 투여군의 임상적 호전률은 시험약 투여 후 2-4일째 각각 91.7%, 85.4% (P=0.31), 치료 종료 시 각각 91.7%, 100% (P=0.15)로 두 군간에 유의한 차이가 없었다. 치료 종료 시 CA 투여군과 CT 투여군의 세균학적 소실률은 모두 100%로 두 군간의 유의한 차이가 없었다(P=0.78). 점막염이 있는 환자로부터 녹색 연쇄알 구균이 분리된 경우는 25예(28.1%)이었으며, 분리된 녹색 연쇄알 구균은 penicillin, ceftriaxone, cefepime, vancomycin에 모두 감수성을 보였다. 약제 관련 이상 반응의 발생 빈도도 두 군간에 유의한 차이가 없었다. 결론 : 발열을 동반한 호중구감소증이 있는 악성 종양환자의 경험적 항생제로서 cefepime 단독요법은 ceftazidime 및 아미노배당체의 병합요법만큼 효과적이고 안전하였다. Background : Broad-spectrum antibiotic therapy has been recommended as an empirical regimen in cancer patients with febrile neutropenia. Cefepime is a fourth generation cephalosporin with good activity against both gram-positive cocci and gram-negative bacilli. Materials and Methods : To compare the efficacy and safety of cefepime alone with ceftazidime plus tobramycin as empirical regimen for adult cancer patients with febrile neutropenia, a randomized, open label, comparative trial was performed. If the patient showed clinical improvent 72 hours, antibiotic could be changed to oral ciprofloxacin. Clinical and microbiological responses were determined at 72 hours and at the end of therapy. To investigate the antimicrobial resistance of viridans streptococci, swab cultures were obtained from throat in all enrolled patients and antimicrobial susceptibility tests were performed by using microdilution method according to the NCCLS. Results : A total of 89 patients were enrolled. Forty-eight patients received cefepime alone (CA), and 41 patients received ceftazidime plus tobramycin (CT). Demographic and baseline clinical characteristics were similar in both groups (P>0.05). The initial clinical success rate at day 2-4 in group CA (91.7%) was similar with that in CT group (85.4%) (P=0.31). At the end of therapy, the final clinical success rate in CA group (91.7%) was similar to that in CT group (100%) (P=0.15). In 18 patients, with microbiologically defined infections, the eradication rate was 100% in both groups. Adverse events including liver dysfunction (21.3%) and renal dysfunction (2.2%), were similar in both groups (P=0.87). Viridans streptococci were isolated from the throat cultures in 25 cases, and all of these strains were susceptible to penicillin (MIC_(90) 0.12 ㎍/mL), cefepime (1 ㎍/mL), and vancomycin (0.12 ㎍/mL). Conclusion : Efficacy and safety of cefepime monotherapy was comparable to the combination of ceftazidime and tobramycin. It could be used as an alternative empirical regimen for treating cancer patients with febrile neutropenia.