레이저 다이싱 장비의 구조 동특성이 빔 안정성에 미치는 영향

박형욱(Hyung Wook Park),노승국(Seung-Kook Ro),박종권(Jong-Kweon Park),이혜진(Hye-Jin Lee),최석우(Seogou Choi) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.5

Inherent merits fabricating thin wafers motivated the development of laser dicing machines. In this study, the dynamic characteristics of the prototype of a laser dicing machine has been evaluated using ANSYS based modal and harmonic analysis. The computation shows that the supporting structure of the laser tube which is a guide of laser beams is stable in terms of the dynamic stiffness. But, the thickness of the beams supporting the upper structure of a laser dicing machine has to be increased.

심혈관 위험을 낮추기 위한 생활습관 관리

박형욱 ( Hyung Wook Park ) 대한내과학회 2014 대한내과학회지 Vol.87 No.2

A healthy lifestyle is important in the prevention and delayed progression of cardiovascular disease (CVD). The intent of this lifestyle management guideline review is to evaluate evidence describing particular dietary patterns, nutrient intake, and levels and types of physical activity associated with CVD risk. The recommendations of this article may be used in management of hypercholesterolemia and hypertension. The proposed guidelines emphasize the importance of dietary patterns rather than individual dietary components. Dietary patterns offer the opportunity to characterize the overall composition and quality of the eating behaviors of a population, such as a Mediterranean-style diet. Dietary sodium and potassium are particularly relevant in CVD due to their effects on blood pressure, while substantial epidemiologic evidence links higher levels of aerobic physical activity to lower rates of CVD and other chronic diseases such as Type 2 diabetes mellitus. This indicates that weight loss and maintenance are critical for prevention and control of CVD risk factors. (Korean J Med 2014;87:131-135)

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 2015 한국CDE학회 논문집 Vol.21 No.2

It is important to devise methods for assisting dentists to consistently determine implant positions and directions and to accurately perform drilling tasks during dental implant surgery. In this paper, we propose a novel approach to tooth implant placement planning which deals with the determination of the positions and directions of multiple implant fixtures for a set of missing mandibular teeth and suggests the selection of the sizes and types of the implant fixtures. We combine Korean standard data in the sizes and positions of human teeth with the patient specific 3D models of mandibular jawbones, nerve curves, and neighboring teeth around the missing teeth in order to determine the positions and directions of the implant fixtures for the missing teeth. Using the geometric and spatial information of the jawbones, the teeth and the implant fixtures, we can construct the 3D models of surgical guide stents which are crucial to perform drilling tasks with ease and accuracy. Adopted in 3D simulation of dental implant placement, the approach can provide surgeon students with good educational contents. We also expect that, with further work, the approach can be used as a useful tool to plan for dental implant surgery.

의료영상으로부터 치아 임플란트 시술용 드릴링 정보 생성방안

박형욱(Hyung-Wook Park),박형준(Hyungjun Park),정상화(Sang-Hwa Jung),김명수(Myung-Su Kim) (사)한국CDE학회 2008 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2008 No.1

초소형 가공 기 구조물 사이즈 최적 설계에 관한 연구

박형욱(Park Hyung Wook),Steven Y. Liang,박종권(Park Jong-Kweon) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.5

In this study, a systematic design scheme was developed to reduce a subjective design of micro/mesoscale machine tools. Based on this developed method, the optimization of the size of micro/mesoscale machine tools was performed. These computations include individual mathematical modeling of key parameters such as volumetric error, machine working space, and static, thermal, and dynamic stiffness. In case of dynamic stiffness, it was supplemented with a hammer impact test to identify the dynamic characteristics of the joints.

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.

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.

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.

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.