동기능부전 환자에서 방실전도계의 전기생리학적 특성에 관한 연구

박형욱(Hyung Wook Park),김준우(Joon Woo Kim),김성희(Seong Hee Kim),조장현(Jang Hyun Cho),안영근(Young Keun Ahn),박주형(Joo Hyung Park),정명호(Myung Ho Jeong),조정관(Jeong Gwan Cho),박종춘(Jong Chun Park),강정채(Jung Chaee Kang) 대한내과학회 1998 대한내과학회지 Vol.55 No.3

N/A Background: It is very important to evalute the function of the atrioventricular conduction system in selecting appropriate pacemaker, pacing and sensing mode in sick sinus syndrome. It has been reported that atrioventricular conduction abnormalities were commonly accompanied with sinus node dysfunction (SND). However, there were several long term follow-up studies indicating that incidence of AV conduction abnormalities was as low as below 1% a year in patients with SND implanted pacemaker. This study was performed to evaluate the properties of the AV conduction system in patients with SND. Subjects and Methods: Patients subjected to this study were fifty-eight who underwent electrophysiologic study on suspicion of SND. Sinus node recovery time (SNRT) was defined as the longest time among the times that sinus rhythm reappeared after rapid atrial pacing for 45 seconds with several cycle lengths, and corrected SNRT (cSNRT) was worked out by subtracting sinus cycle length (SCL) from SNRT. Criteria for sinus node dysfunction were 1550 msec or more on SNRT, 550 msec or more on cSNRT and group A (23 cases, 58±13 yrs) was defined as SND not retrieved to normal after intravenous administration of atropine 1-2 mg, group B (21 cases, 52±14 yrs) was retrieved to normal and group C (14 cases, 54±13 yrs) was normal control group. Abnormalities of the AV conduction system were defined as 150 msec or more on AH interval, 500 msec or more on AVblock cycle length (AV-BCL), 4% msec or more on AV nodeeffective refractory period (AVN-ERP). Results: SCI. in group A, B, C was 1197±340 msec, 1215±273 msec, and 898±129 msec, respectively at baseline and 886±218 msec, 798±106 msec, and 722±110 msec respectively after atropine administration, showing a significant prolongation of SCL in group A and B at baseline (p<0.001) and group A after atropine administration (p<0.05). SNRT in group A, B, C was 3520±1817 msec, 3180±2390 msec, and 1282±116, respectively at baseline and 4155±4281 msec, 1237±210 msec, 1020±245 msec, respectively after atropine administration, showing a significant prolongation of SNRT in group A and B at baseline (p<0.001) and group A after atropine administration (p<0.05). AH intervals at baseline and after atropine administration were 107±27 msec and 100±20 msec in group A, 101±21 and 91±14 in group B, and 118±32 and 83±23 in group C, showing no significant difference between 3 groups. AV-BCLs at baseline and after atropine administration were 428±151 msec and 453±301 msec in group A, 525±140 and 370±53 in group B, and 461±120 361±94 in group C, showing no significant difference between 3 groups. AVN-ERP was 315±57 msec in group A, 343±132 msec in group B, 347±132 in group C, showing no significant difference between 3 groups. There was no significant difference in the incidences of cases with abnormal AH interval, AV-BCI AVN-ERP, HV interval between 3 groups. AV block greater than second degree was observed in one patient of group A but none of group B and C. Conclusions: Atrioventricular conduction abnormalities in patients with sinus node dysfunction were not mare common than control subjects, Therefore, atrial pacing rather than ventricular or dual chamber pacing may be safely selected as a permanent pacing mode for sick sinus syndrome with no combined significant AV block.

후방 복합충돌시 승객보호에 관한 연구

박형욱(Hyung Wook Park),신세리(Seri Shin),김성수(Sung Soo Kim) 한국자동차공학회 2017 한국자동차공학회 부문종합 학술대회 Vol.2017 No.5

다분야통합최적설계를 위한 적응분해기법

박형욱(Hyung-Wook Park),최동훈(Dong-Hoon Choi),안병호(Byung-Ho Ahn) 한국항공우주학회 2003 韓國航空宇宙學會誌 Vol.31 No.5

표준 치아 크기 및 배열 정보를 이용한 다중 치아 임플란트 식립계획 방안

박형욱(Hyung-Wook Park),박상진(Sang-Jin Park),박형준(Hyungjun Park) (사)한국CDE학회 2013 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2013 No.1

최근 의료영상 기반 3D 데이터가 임플란트 시술계획 수립에 널리 활용하고 있으나 식립 위치와 방향 선정의 경우 시술자의 경험 및 주관적 판단에 의존되어 시술자 간 상당한 편차가 존재한다. 본 논문에서는 한국인 표준모델을 토대로 얻어진 하악 치아들의 크기 및 배열 정보를 환자에 따른 식립 부위 주변 치아 및 구강 정보와 접목하여 다중 임플란트 식립 위치 및 방향을 결정하고, 이를 바탕으로 임플란트 크기 및 유형을 선정하는 방안을 제안한다. 얻어진 식립정보를 이용하여 식립보조도구(surgical stents)의 3D 모델을 생성할 수 있으며, 치아 임플란트 시술용 교육 컨텐츠로 활용될 수 있고, 식립계획 수립을 위한 유용한 정보로 활용될 수 있다.

감각형 인터페이스를 이용한 치아 임플란트 시술 시뮬레이션 방안

박형욱(Hyung-Wook Park),김명수(Myongsoo Kim),박형준(Hyungjun Park) 대한산업공학회 2008 대한산업공학회 추계학술대회논문집 Vol.2008 No.11

현재의 임플란트 시술방식에서는 환자의 석고 모형을 이용한 의사의 경험적 판단에 의거하여 fixture의 식립 자세가 결정되며, 이로 인한 가상 치아 및 시술용 보조도구의 생성을 통해 드릴링 작업 및 식립작업이 이루어진다. 하지만 이러한 방식은 시술 상의 오류에 따른 품질저하를 가져올 가능성을 가지고 있다. 본 논문에서는 이러한 기존 방식의 문제점을 완화하기 위하여 주어진 의료영상을 바탕으로 치아 임플란트 시술에 관한 정보를 획득하여, 임플란트 식립 simulator를 구성하였으며, 드릴링 및 식립 작업이 보다 실감나도록 감각형 인터페이스 장치인 haptic device를 접목하는 방안을 제시한다. 제시된 임플란트 시술에 관한 정보 획득 방안은 주요 4단계로 이루어지는데, MimicsTM 를 이용한 의료 영상으로부터 턱뼈 및 치아/신경관에 대한 CAD 모델 획득 단계, SimplantTM 를 이용한 CAD 모델 및 의료영상을 이용한 임플란트 fixture 선정 및 식립 자세 결정 단계, 생성된 턱뼈 모델을 바탕으로 한 임플란트 시술용 보조도구의 3차원 모델 생성단계, 치아 임플란트 시술정보 시각화 및 응용 단계로 이루어진다. 응용단계에서는 치아 임플란트 가상 시뮬레이션 환경에서 감각형 인터페이스 장치인 haptic device를 이용하여 직접 드릴링하는 효과를 실감나게 느낄 수 있으며, 버튼의 이벤트를 통하여 치아 및 턱뼈의 사실적인 드릴링에 대한 예행연습이 가능하다. 또한 이는 치의학 수업을 받는 학생들에게는 보다 실감나는 교육용 컨텐츠로 사용될 수 있다.

당뇨병 환자와 정상 혈당 환자에서 폐결핵의 임상적, 방사선학적 차이

박형욱 ( Hyung Wook Park ),도경록 ( Kyong Rock Do ),전은경 ( Eun Kyoung Jeon ),박진영 ( Jin Young Park ),이자영 ( Ja Young Lee ),김지은 ( Ji Eun Kim ),박용근 ( Young Kun Park ),이상록 ( Sang Rok Lee ),안진영 ( Jin Young An ) 대한결핵 및 호흡기학회 2008 Tuberculosis and Respiratory Diseases Vol.64 No.4

유한요소 해석을 이용한 특수선용 신축 이음관 개발

박형욱(Park Hyung-Wook),김정환(Kim Jung-Hwan),조종래(Cho Jong-Rae) 한국유체기계학회 2008 유체기계 연구개발 발표회 논문집 Vol.2008 No.-

PIPE LINE, DUCT, VESSEL are changed the length by the individual thermal expansion and contraction according to temperature increase. And will forward to the high-strength anchor point. The compensator is used to give the space for these changes set. This study was conducted to development the useful environment and the range of the high temperature/high pressure compensator in domestic produced which can apply to special ship. In addition, the compensator which had been applied to the reinforcement carried out the shape optimal design using the structural analysis.

크리깅 근사모델 모델을 이용한 LMTT 이동체의 구조최적설계

박형욱(Hyung Wook Park),한동섭(Dong Seop Han),이권희(Kwon Hee Lee),한근조(Geun Jo Han) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

LMTT (Linear Motor-based Transfer Techn-ology) is a horizontal transfer system for the yard automation, which has been proposed to take the place of AGV(Automated Guided Vehicle) in the maritime container terminal. The system is base don PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle car. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research, the DACE modeling known as the one of Kriging interpolation, is introduced to obtain the surrogate approximation model of the structural responses. Then the GRG(Generalized Reduced Gradient) method built in Excel is adopted to determine the optimum. The objective function is set up as weight. On the contrary, the design variables are considered as transverse, longitudinal and wheel beam's thicknesses, and the constraints are the maximum stresses generated by four loading conditions.

식립 보조도구를 이용한 3D 치아 임플란트 시술 시뮬레이션

박형욱(Hyung-Wook Park),김명수(Myong-Soo Kim),박형준(Hyungjun Park) (사)한국CDE학회 2011 한국CDE학회 논문집 Vol.16 No.3

Surgeon dentists usually rely on their experiential judgments from patients’ oral plaster casts and medical images to determine the positional and directional information of implant fixtures and to perform drilling tasks during dental implant surgical operations. This approach, however, may cause some errors and deteriorate the quality of dental implants. Computer-aided methods have been introduced as supportive tools to alleviate the shortcomings of the conventional approach. In this paper, we present an approach of 3D dental implant simulation which can provide the realistic and immersive experience of dental implant information. The dental implant information is primarily composed of several kinds of 3D mesh models obtained as follows. Firstly, we construct 3D mesh models of jawbones, teeth and nerve curves from the patient’s dental images using software Mimics™. Secondly, we construct 3D mesh models of gingival regions from the patient’s oral impression using a reverse engineering technique. Thirdly, we select suitable types of implant fixtures from fixture database and determine the positions and directions of the fixtures by using the 3D mesh models and the dental images with software Simplant™. Fourthly, from the geometric and/or directional information of the jawbones, the gingival regions, the teeth and the fixtures, we construct the 3D models of surgical guide stents which are crucial to perform the drilling operations with ease and accuracy. In the application phase, the dental implant information is combined with the tangible interface device to accomplish 3D dental implant simulation. The user can see and touch the 3D models related with dental implant surgery. Furthermore, the user can experience drilling paths to make holes where fixtures are implanted. A preliminary user study shows that the presented approach can be used to provide dental students with good educational contents. With future work, we expect that it can be utilized for clinical studies of dental implant surgery.

3차원 기하 처리와 유한요소 분석을 이용한 치아 임플란트 식립 계획 수립

박형욱(Hyung-Wook Park),박철우(Chul-Woo Park),김명수(Myong-soo Kim),박형준(Hyungjun Park) (사)한국CDE학회 2012 한국CDE학회 논문집 Vol.17 No.4

In order to make dental implant surgery successful, it is important to perform proper planning for dental implant placement. In this paper, we propose a decent approach to dental implant placement planning based on geometric processing of 3D models of jawbones, a nerve curve and neighboring teeth around a missing tooth. Basically, the minimum enclosing cylinders of the neighboring teeth around the missing tooth are properly used to determine the position and direction of the implant placement. The position is computed according to the radii of the cylinders and the center points of their top faces. The direction is computed by the weighted average of the axes of the cylinders. For a cylinder whose axis passes the position along the direction, its largest radius and longest length are estimated such that it does not interfere with the neighboring teeth and the nerve curve, and they are used to select the size and type of an implant fixture. From the geometric and spatial information of the jawbones, the teeth and the fixture, we can construct the 3D model of a surgical guide stent which is crucial to perform the drilling operation with ease and accuracy. We have shown the validity of the proposed approach by performing the finite element analysis of the influence of implant placement on bone stress distribution. Adopted in 3D simulation of dental implant placement, the approach can be used to provide dental students with good educational contents. It is also expected that, with further work, the approach can be used as a useful tool to plan for dental implant surgery.