• 한국컴퓨터그래픽스학회논문지
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• 제26권1호
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• pp.1-6
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• 2020

소동물의 슬개골 수술은 인간의 뼈보다 약하여 수술의 난이도가 어렵기 때문에, 소 동물의 슬개골 탈구 치료 수술 과정의 학습은 수의사에게 매우 중요하다. 소 동물의 슬개골 수술 훈련은 사체를 이용한 훈련을 하고 있으나 소 동물의 사체가 부족하기 때문에 시청각 자료나 수술 참관으로 수술을 학습하고 있어 수의학과 학생 및 전문 수의사들에게 충분한 훈련 환경이 제공되지 못하는 상황이다. 본 논문에서는 이러한 문제를 해결하기 위하여 소동물의 슬개골 수술을 위한 햅틱 시뮬레이터를 제안한다. 제안한 시뮬레이터는 슬개골 드릴링 수술에 적용시켰으며 소동물의 드릴링에 대한 Force Feedback을 모델링하고 햅틱 인터페이스를 제공하고, 사용자가 몰입하여 수술 경험을 할 수 있는 워크 벤치를 제공하였다. 본 논문에서 제안된 슬개골 햅틱 시뮬레이터가 제공하는 드릴링 과정에서 햅틱 피드백에 대한 사용자 평가 결과 유의미한 결과를 얻을수 있었다.

• 대한심미치과학회지
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• 제32권2호
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• pp.54-68
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• 2023

디지털 방법을 사용한 무치악의 임플란트 치료계획은 surgical guide design으로 구체화된다. Surgical guide를 제작할 때, 우리는 먼저 최종 보철의 형태를 가상공간에 구현한 후 이를 바탕으로 식립 계획을 구체화하게 된다. 그러나 완전무치악 환자는 치아배열의 기준이 없고 악간관계가 정립되어 있지 않아 최종 보철의 형태를 짐작하기 어려워 surgical guide를 만드는 데 어려움이 있다. 이때 기존의 만족스러운 총의치나 부분의치, 잔존치 등이 존재한다면 그 치아배열이 가상적인 최종 보철의 reference가 될 수 있다. 만약 이러한 reference가 부재하거나 만족스럽지 못하다면, 진단용 목적으로 총의치를 제작하되 이를 구내에서 검증하는 과정이 필요하다. 이러한 과정을 통해 surgical guide를 제작할지라도 구내 상황에 따라 implant의 위치가 계획한 것과 다르게 식립될 수 있으며, 만약 guide의 positioning이 잘못된다면 그 오차는 모든 implant의 위치를 변위시킬 수 있으므로 guide 수술이 오히려 재앙으로 다가올 수 있다. 본 기고에서는 치아 배열의 reference가 될 수 있는 자료들을 적절한 시기에 채득하여 이를 디지털 공간에 이전 및 통일된 좌표계로 정렬하는 방법에 대해 논의하고, 또한 이렇게 수립된 식립계획을 현실의 구강에 적은 오차로 이전 및 정렬하는 방법에 대해 소개하여 일관적이고 체계적인 무치악 가이드 디자인의 프로토콜 정립에 대해 의견 개진하려 한다.

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.90-93
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• 2015

The fibula free flap has now become the most reliable and frequently used option for mandible reconstruction. Recently, three dimensional images and printing technologies are applied to mandibular reconstruction. We introduce our recent experience of mandibular reconstruction using three dimensionally planned fibula free flap in a patient with gunshot injury. The defect was virtually reconstructed with three-dimensional image. Because bone fragments are dislocated from original position, relocation was necessary. Fragments are virtually relocated to original position using mirror image of unaffected right side of the mandible. A medical rapid prototyping (MRP) model and cutting guide was made with 3D printer. Titanium reconstruction plate was adapted to the MRP model manually. 7 cm-sized fibula bone flap was designed on left lower leg. After dissection, proximal and distal margin of fibula flap was osteotomized by using three dimensional cutting guide. Segmentation was also done as planned. The fibula bone flap was attached to the inner side of the prebent reconstruction plate and fixed with screws. Postoperative evaluation was done by comparison between preoperative planning and surgical outcome. Although dislocated condyle is still not in ideal position, we can see that reconstruction was done as planned.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권4호
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• pp.256-261
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• 2017

Objectives: The concept of natural head position (NHP) was first introduced by Broca in 1862, and was described as a person's stable physiologic position "when a man is standing and his visual axis is horizontal." NHP has been used routinely for clinical examination; however, a patient's head position is random during cone-beam computed tomography (CBCT) acquisition. To solve this problem, we developed an accelerometer to record patients' NHP and reproduce them for CBCT images. In this study, we also tested the accuracy and reproducibility of our accelerometer. Materials and Methods: A total of 15 subjects participated in this study. We invented an accelerometer that measured acceleration on three axes and that could record roll and pitch calculations. Recorded roll and pitch data for each NHP were applied to a reoriented virtual image using three-dimensional (3D) imaging software. The data between the 3D models and the clinical photos were statistically analyzed side by side. Paired t-tests were used to statistically analyze the measurements. Results: The average difference in the angles between the clinical photograph and the 3D model was $0.04^{\circ}$ for roll and $0.29^{\circ}$ for pitch. The paired t-tests for the roll data (P=0.781) and the pitch data (P=0.169) showed no significant difference between the clinical photographs and the 3D model (P>0.05). Conclusion: By overcoming the limitations of previous NHP-recording techniques, our new method can accurately record patient NHP in a time-efficient manner. Our method can also accurately transfer the NHP to a 3D virtual model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.826-840
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• 2020

Vertigo is one of the most common complaints encountered by physicians and the patients are steadily increasing. These patients are exposed to the risk of secondary accidents such as falls due to vertigo. There are two ways to improve this symptom: medication and rehabilitation. Although temporary symptomatic improvement may be expected in patients treated with medication, vertigo may recur and medication can delay central compensation. In contrast vestibular rehabilitation exploits central mechanisms of neuroplasticity to increase postural stability and enhance visual-vestibular interactions in situations that generate conflicting sensory information. However, vestibular rehabilitation may be compromised by incorrect performance of exercises, and there is a need for active effort and interest from the patient during rehabilitation. To solve these problems, we decided to apply FOVE HMD for eye-tracking and Unity3D to create virtual reality. The proposed eye-tracking based algorithm calculates the concentration of users with eye tracking data and calculates the motion width of the patient with nystagmus, thus the severity of the patient according to the score can be determined. According to our experimental test against healty group and patients group, this result showed the meaningful data to use define the contents result.

• Journal of Computing Science and Engineering
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• 제10권3호
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• pp.75-84
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• 2016

Medical cyber-physical systems (MCPS) integrate sensors, actuators, and software to improve patient safety and quality of healthcare. These systems introduce major challenges to safety analysis because the patient's physiology is complex, nonlinear, unobservable, and uncertain. To cope with the challenge that unidentified physiological parameters may exhibit short-term variances in certain clinical scenarios, we propose a novel run-time predictive safety monitoring technique that leverages a maximal model coupled with online training of a computational virtual subject (CVS) set. The proposed monitor predicts safety-critical events at run-time using only clinically available measurements. We apply the technique to a surgical glucose control case study. Evaluation on retrospective real clinical data shows that the algorithm achieves 96% sensitivity with a low average false alarm rate of 0.5 false alarm per surgery.

• 한국정밀공학회지
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• 제27권2호
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• pp.137-144
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• 2010

In general, spinal fusion surgery takes pressure off the pain induced nerves, by restoring the alignment of the spine. Therefore spinal fixation system is used to maintain the alignment of spine. In this study, a biomechanical study was performed comparing the SROM(Spinal Range Of Motion) of three types of system such as Rigid, Dynesys, and Fused system to analyze the behavior of spinal fixation system inserted in vertebra. Dynesys system, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve inter-segmental kinematics and alleviate loading at the facet joints. In this study, SROM of inter-vertebra with spinal fixation system installed in the virtual vertebra from L4 to S1 is estimated. To compare with spinal fixation system, a simulation was performed by BRG. LifeMOD 2005.5.0 was used to create the human virtual model of spinal fixation system. Through this, each SROM of flexion, extension, lateral bending, and axial rotation of human virtual model was measured. The result demonstrates that the movement of Dynesys system was similar to normal condition through allowing the movement of lumbar.

• 조명전기설비학회논문지
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• 제13권1호
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• pp.111-118
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• 1999

함반영 촉각장치(Force-Reflecting haptic Interface)는 인간이 컴퓨터에 의해 생성한 가상의 세계에 손의 위치 정보를 제공하고 가상의 손이 가상 환경에 접촉했을 때 인간에게 촉각을 전달하는 장치이다. 본 논문에서는 컴플라이언스 제어가 비교적 용이한 초음파 모터 액츄에이터를 사용하여 직접구동 방식으로 촉각장치를 설계하였다. 렌더링 알고리즘을 이용하여 가상의 벽, 가상 버튼, 가상 구멍 등의 기본적인 역감실험을 한 결과 힘 반영에 의한 역감을 제시받을 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권5호
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• pp.353-357
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• 2020

Fractures of the orbital floor and walls are among the most frequent maxillofacial fractures. Virtual three-dimensional (3D) planning and use of patient-specific implants (PSIs) could improve anatomic and functional outcomes in orbital reconstruction surgery. The presented case was a victim of a terrorist attack involving improvised explosive devices. This 58-year-old female suffered severe wounds caused by a single piece of metal from a bomb, shattering the left orbital floor and lateral orbital wall. Due to remaining hypotropia of the left eye compared to the right eye, late orbital floor reconstruction was carried out with a personalised 3D printed titanium implant. We concluded that this technique with PSI appears to be a viable method to correct complex orbital floor defects. Our research group noted good aesthetic and functional results one year after surgery. Due to the complexity of the surgery for a major bony defect of the orbital floor, it is important that the surgery be executed by experienced surgeons in the field of maxillofacial traumatology.

• Archives of Plastic Surgery
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• 제37권4호
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• pp.351-360
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• 2010

Purpose: As the influence of mass media increases, the general standard of attractiveness or beauty of a face also changes. The primary purpose of the study is to find out the factors of the attractive and beautiful face recognized by public. Methods: We picked out standard model photography and operated with Adobe$^{(R)}$ Photoshop$^{(R)}$ and Monariza$^{(R)}$ virtual plastic surgery program. The contour of face, eye, nose, forehead, zygoma, chin and proportion of upper, middle, lower face were changed. The interview survey was conducted through structured standard photo for 310 respondents. That was utilized in the final analysis. Multiple regression analysis was executed by SPSS 12.0. It was used to deal with statistical data and all the other necessary analysis. Results: According to general characteristics of the respondents, many differences were found in preferred face and facial aesthetic subunits. The younger generation preferred the lozenge and inverted triangle shape contour. The respondents over 40 of age preferred the egg shape contour. In chin and zygoma contour, the respondents at the age of 20 preferred distinctly small chin and relatively small lower face. On the other hand, the respondents over 40 of age preferred the wide zygoma relatively. In the proportion of upper, middle, lower face, 51.0% of respondents answered 1 : 1 : 1. If they want to have an aesthetic operation, they preferred protruding forehead. Also they preferred the small chin and V-shaped chin in frontal view. Conclusion: Many respondents preferred to have a plastic surgery for the better facial subunit. The statistical evidence from this study suggests that the harmony and balance of facial aesthetic subunits make attractive and beautiful face.