• 대한치과보철학회지
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• 제26권1호
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• pp.63-84
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• 1988

Recently the instantaneous centre concept has been used to understand the biomechanics by which a tissue derangement causes a mechanical derangement in temporomandibular joint. In this study, four male subjects without temporomandibular joint disorder and malocclusion were selected for the determination of the instantaneous centre of rotation (I.C.R) in the mandibular movement. The habitual opening and closing paths were recorded on the sagittal plate by two spring pencils attached on the lower anterior teeth which was designed for this study, and the I.C.R. was calculated by the computer program of Rouleaux's method. Also the computer graphic opening and closing movements of mandible were obtained according to the determined I.C.R. The results obtained from this study were as follows. 1. The instantaneous centres of rotation were not positioned within the condyle in the mandibular opening and closing movement. 2. There was some similarity between the anatomical curvature of the articular emience and the movement pattern of condyle. 3. The opening path and the closing path of the most superior pl)int of the condyle stowed a slight difference. 4. At the early stage of the habitual opening movement, the condyle was moved downward. 5. The opening and closing mandibular movements were simulated by the instantaneous centre of rotation which was determined by the computer program of Rouleaux's method.

• 한국방사선학회논문지
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• 제6권4호
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• pp.299-303
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• 2012

자기공명 관절 조영술(Shoulder MR Arthrography)는 견관절(Shoulder joint) 의 복잡한 해부학적 구조에 관하여 정확한 영상평가를 진단하기 위해 시행 한다. 우리는 어께 상완골(Shoulder humerus) 의 다양한 position인 Neutral position, Internal rotation position, External rotation position 에 관하여 Shoulder joint의 해부학 적인 회전 변화가 견관절 자기공명(Shoulder MRI) 영상에 어떤 진단적 결과를 가져오는가에 대해 상호 비교 하였다. 또한 환자의 정확한 촬영자세 유지를 위해 촬영 보조기구를 만들었다. 이 보조기구는 Modeling 설계에 의해 우리가 직접 제작한 자기공명 견관절 조영술 보조 기구이다. 이 보조기구를 사용하여 촬영한 결과 다음과 같은 결론을 도출해 내었다. External rotation position 에 의한 Shoulder MRArthrography 검사가 Shoulder joint의 중요 해부학적 구조인 Biceps tendon, Supera-spiatus tendon, Sub-scapularis tendon, Labrum, Sub-acromial space 의 해부학적 평가에서 제일 적합하다는 진단적 평가를 얻었다.

• 로봇학회논문지
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• 제13권2호
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• pp.113-120
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• 2018

To fly a drone or unmanned aerial vechicle(UAV) safely, its pilot needs to maintain high situation awareness of its flight space. One of the important ways to improve the flight space awareness is to integrate both the global and the local navigation map a drone provides. However, the drone pilot often has to use the inconsistent reference frames or perspectives between the two maps. In specific, the global navigation map tends to display space information in the third-person perspective, whereas the local map tends to use the first-person perspective through the drone camera. This inconsistent perspective problem makes the pilot use mental rotation to align the different perspectives. In addition, integrating different dimensionalities (2D vs. 3D) of the two maps may aggravate the pilot's cognitive load of mental rotation. Therefore, this study aims to investigate the relation between perspective difference ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$) and the map dimensionality matches (3D-3D vs. 3D-2D) to improve the way of integrating the two maps. The results show that the pilot's flight space awareness improves when the perspective differences are smaller and also when the dimensionalities between the two maps are matched.

• Structural Engineering and Mechanics
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• 제74권2호
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• pp.189-199
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• 2020

Researchers have elaborated several accurate methods to calculate member-end rotations or moments, directly, for bridge-type structures. Recently, the concept of rotation and moment propagation (RMP) has been presented considering bending flexibility, only. Through which, in spite of moment distribution method, all joints are free resulting in rotation and moment emit throughout the structure similar to wave motion. This paper proposes a new set of closed-form equations to calculate member-end rotation or moment, directly, comprising both shear and bending flexibility. Furthermore, the authors program the algorithm of Timoshenko beam theory cooperated with the finite element. Several numerical examples, conducted on the procedures, show that the method is superior in not only the dominant algorithm but also the preciseness of results.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.15-20
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• 2007

Recently the machine industry is rapidly advanced for improving productivity. Especially an effort decreased error factors of machine tool continuously is being studied. In this paper, we propose a method that decreased vibration in the high speed spindle. By appling 6-sigma technique(DMADOV), we can grasp the influence between the housing design and a rotation accuracy. For a correct conclusion, we measure an actual spindle and analysis by $ARMD^{(R)}$(rotation analysis program). inally we find out influenceable design factors and the improvement condition about 20.7%.

• Structural Engineering and Mechanics
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• 제51권4호
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• pp.601-625
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• 2014

Based on continuum mechanics and the principle of virtual displacements, incremental total Lagrangian formulation (T.L.) and incremental updated Lagrangian formulation (U.L.) were presented. Both T.L. and U.L. considered the large displacement stiffness matrix, which was modified to be symmetrical matrix. According to the incremental updated Lagrangian formulation, small strain, large displacement, finite rotation of three dimensional Timoshenko fiber beam element tangent stiffness matrix was developed. Considering large displacement and finite rotation, a new type of tangent stiffness matrix of the beam element was developed. According to the basic assumption of plane section, the displacement field of an arbitrary fiber was presented in terms of nodal displacement of centroid of cross-area. In addition, shear deformation effect was taken account. Furthermore, a nonlinear finite element method program has been developed and several examples were tested to demonstrate the accuracy and generality of the three dimensional beam element.

• 문화기술의 융합
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• 제5권3호
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• pp.241-249
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• 2019

본 연구의 목적은 경부스트레칭프로그램이 스마트폰을 과다 사용으로 발생하는 경부통증, 피로, 관절운동범위에 미치는 효과를 평가하기 위함이다. 스마트폰을 과다 사용하는 간호대학생 실험군(n=25), 대조군(n=27)을 대상으로 경부스트레칭프로그램 적용 전 후 경부통증, 피로, 관절운동범위의 정도를 측정하였다. 대상자의 일반적인 특성과 경부통증, 피로, 관절운동범위는 기술통계와 추론통계를 사용하여 분석하였다. 경부통증, 피로, 관절운동범위에 대한 경부스트레칭프로그램의 효과는 독립 t 검정으로 분석하였다. 분석 결과, 대상자에게 경부스트레칭프로그램 적용 후 경부통증(t=2.86, p=.006), 피로(t=5.44, p<.001). 굴곡((t=-2.10, p=.041), 신전(t=-2.84, p=.006), 오른쪽 측방굴곡(t=-2.4, p=.047) 왼쪽 측방의 굴곡(t=-2.05, p=0.46)) 및 오른쪽 회전 범위(t=-4.48, p<.001), 왼쪽 회전범위(t=-3.38, p=.001)가 개선되었다. 이 연구의 결과는 경부스트레칭프로그램이 스마트폰 사용에 따른 근골격계 장애에 건강 문제에 대한 효과적인 중재로 사용될 수 있다는 것을 보여준다.

• Imaging Science in Dentistry
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• 제31권1호
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• pp.23-34
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• 2001

Purpose : To develop a new subtraction program for registering digital periapical images based on the correspondence of anatomic structures. Materials and Methods: The digital periapical images were obtained by Digora system with Rinn XCP equipment after translation of 1-16 mm, and rotation of 2-20° at the premolar and molar areas of the human dried mandible. The new subtraction program, NIH Image program and Emago/Advanced program were compared by the peak-signal-to noise ratio (PSNR). Results : The new subtraction program was superior to NIH Images program and Emagol Advanced program up to 16 mm translation and horizontal angulation up to 4°. Conclusion: The new subtraction program can be used for subtracting digital periapical images.

• 한국전문물리치료학회지
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• 제8권1호
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• pp.35-50
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• 2001

The purposes of this study were to investigate the therapeutic effects of an early exercise program after mastectomy and to provide the early exercise program protocol for patients who had undergone mastectomy. The subjects were seventy women who were diagnosed with breast cancer. They were randomly as signed either to a experimental group (n=35) that received early postoperative exercise program or to a control group (n=35) that received only education by nurses. Data were obtained for each patient from goniometric measurements of shoulder flexion, abduction, external rotation, 10 elements of functional performance, and subjective pain evaluation using visual analogue scale (VAS). All variables were measured preoperatively, three days postoperatively, and one month postoperatively. Data were compared by groups using independent t-test and Mann-Whitney U test for parametric or non-parametric data, respectively. There were no significant differences between the groups for all variables preoperatively and at three days postoperatively. But there were significant differences at one month postoperatively. The experimental group showed a statistically significant increases in shoulder flexion, abduction, and external rotation and in the pain VAS at one month postoperatively (p<.05). Also, at one month postoperatively, the experimental group had less difficulty with three elements of functional performance-doing up a 'back' zippered article of clothing, reaching the ipsilateral scapula, and contralateral scapula with the fingers on the operated side-than the control group (p<.05). The results of this study suggest that, after mastectomy, the early exercise program conducted by a well-trained physical therapist can make a significant contribution to the return of more normal shoulder function and activities of daily living and to an increased quality of life.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권6호
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• pp.559-565
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• 2006

The aim of this study was to evaluate the amount and interrelationship of the soft and hard tissue changes after simultaneous maxillary clockwise rotation and mandibular setback surgery in skeletal class III malocclusion. The sample comprised of 16 adult patients who had anteroposterior skeletal discrepancy. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of Le fort I Osteotomy and bilateral saggital split ramus osteotomy. The presurgical (T1) and postsurgical (T2) lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/PC program. The results demonstrated a decrease in the vertical dimension in the soft and hard tissue. The nasolabial angle was increased and the mentolabial angle was decreased. The results showed also many statistically significant correlations(p<0.05). The lower lip closely followed the skeletal movement of the B- point in the horizontal plane. The double jaw rotation surgery can afford a good solution to solve the problems of class III malocclusion cases.