• 대한치과교정학회지
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• 제27권2호
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• pp.221-230
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• 1997

두경부 자세는 생리적 활동의 기능적 요구에 의해 영향을 받으며 두개 안면 골격의 형태학적 발육에 직접 혹은 간접으로 영향을 미치는 것으로 알려져 있다. 대부분의 연구에서 안모형태와 설골의 위치,두경부 자세는 서로 매우 높은 상관 관계를 나타내며, 특히 하악골의 전후방 위치가 두경부 자세와 가장 큰 상관 관계를 가지는 것으로 알려져 있다. 이와같은 연구에서는 대부분 연구대상을 Natural Head Position(NHP)으로 유도하였으며 여러 연구자들에 의해 NHP의 재현성이 매우 높다고 알려져있으나, 교정환자를 위해 통법의 두부방사선 사진을 찍은 경우에는 어떠한 상관관계가 있는지에 대해선 연구가 적은 실정이다. 이에 본 연구에서는 여러 안모 유형의 성인 여자 환자를 대상으로 수직기 준선을 나타내는 수직선 추를 이용하여 통법에 따라 채득한 치료전 측모 두부방사선 사진을 이용하여 Wits와 ANB을 기준으로 골격성 부정교합군을 I, II, III로 분류하였으며 각 군별 20명씩 선택하여 두경부 위치와 설골 위치의 부정교합 분류에 따른 상관성 여부를 알아보아 다음과 같은 결론을 얻었다. 1. 두개저에 대한 설골의 수직적 위치 비교시 Cl II에 비해 C1 III 에서 설골이 더 하방 위치하였다 2. 경추에 대한 설골의 전후방 위치 비교시 Cl II 에 비해 Cl III 에서 설골이 더 전방 위치 하였다. 3. 하악에 대한 설골의 수직적 위치는 Cl I, II, III 간에 통계학적 유의차가 없었다. 4. 악골의 전후방 관계를 나타내는 A N B, Wits 와 설골의 위치 사이에는 통계학적 상관관계를 관찰할 수 없었다. 5. Cl II 에서 나타나는 상대적인 두부 신전 (extension)은 Bjork Sum, ANB와 역상관관계를 나타냈다 6. Cl II 와 Cl III 에서 Post to Ant Facial Height 과 NSL/VER은 순상관관계를 나타냈다.

• 대한통합의학회지
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• 제5권2호
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• pp.11-17
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• 2017

Purpose : The aim of this study was to verify differences in cervicocephalic joint position sense error after different sustained sitting postures in healthy young adults. Methods : Twenty-five healthy adults(12 men, 13 women) participated in this study. Repositioning errors of neck movement were observed in participants during joint repositioning tasks. During 2 test days with a 1-week interval, the participants performed forward head posture and upright sitting posture in random order. Both head-to-neutral(HTN) and head-to-target(HTT) tasks were performed on each day. On the first day, the participants sat slouched or upright for 10 minutes. Then, they sat upright and moved their heads at a self-selected speed with their eyes-closed to pre-determined neutral and target positions as accurately as possible. The participants noticed that when they reached a pre-determined position, the errors between pre-determined neutral and target positions and current position was recorded. The tasks consisted of flexion, extension and lateral bending. On the second day, the same test was performed after another sitting posture for 10 minutes. Repositioning error values were collected by using a smart phone-based inclinometer. The mean value for three trials was used for data analysis. A paired t-test was used for statistical analysis. Results : Significant differences in joint repositioning errors were found between the repositioning error after different sitting postures on the sagittal plane for both the HTN and HTT tasks (P<.05). No significant differences in errors on the coronal plane were found (P>.05). Conclusion : Cervicocephalic joint position sense can be affected by sitting postures, especially on the sagittal plane.

• 제어로봇시스템학회논문지
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• 제16권1호
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• pp.90-95
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• 2010

This paper describes the development of integrated head and eye tracker system. Vision based head tracker is performed and it has 7mm error in 300mm translation. The epi-polar method and point matching are used for determining a position of head and rotational degree. High brightness LEDs are installed on helmet and the installed pattern is very important to match the points of stereo system. Eye tracker also uses LED for constant illumination. A Position of gazed object(3m distance) is determined by pupil tracking and eye tracker has 1~5 pixel error. Integration of result data of each tracking system is important. RS-232C communication is applied to integrated system and triggering signal is used for synchronization.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.36.1-36.7
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• 2015

Background: This study was performed to evaluate three-dimensional positional change of the condyle using three-dimensional computed tomography (3D-CT) following unilateral sagittal split ramus osteotomy (USSRO) in patients with mandibular prognathism. Methods: This study examined two patients exhibiting skeletal class III malocclusion with facial asymmetry who underwent USSRO for a mandibular setback. 3D-CT was performed before surgery, immediately after surgery, and 6 months postoperatively. After creating 3D-CT images by using the In-vivo $5^{TM}$ program, the axial plane, coronal plane, and sagittal plane were configured. Three-dimensional positional changes from each plane to the condyle, axial condylar head axis angle (AHA), axial condylar head position (AHP), frontal condylar head axis angle (FHA), frontal condylar head position (FHP), sagittal condylar head axis angle (SHA), and sagittal condylar head position (SHP) of the two patients were measured before surgery, immediately after surgery, and 6 months postoperatively. Results: In the first patient, medial rotation of the operated condyle in AHA and anterior rotation in SHA were observed. There were no significant changes after surgery in AHP, FHP, and SHP after surgery. In the second patient, medial rotation of the operated condyle in AHA and lateral rotation of the operated condyle in FHA were observed. There were no significant changes in AHP, FHP, and SHP postoperatively. This indicates that in USSRO, postoperative movement of the condylar head is insignificant; however, medial rotation of the condylar head is possible. Although three-dimensional changes were observed, these were not clinically significant. Conclusions: The results of this study suggest that although three-dimensional changes in condylar head position are observed in patients post SSRO, there are no significant changes that would clinically affect the patient.

• 구강회복응용과학지
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• 제35권2호
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• pp.90-97
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• 2019

목적: 교합접촉면적에 관련된 이전의 연구들은 교합두께 수준이나 교합측정방법 상 부정확성이 한계로 지적되어 왔다. 본 연구의 목적은 머리 위치가 교합접촉면적에 미치는 영향을 광조사교합분석법을 이용하여 조사하는 것이다. 연구 재료 및 방법: 건전한 치열을 갖는 54명(남성 44명, 여성 10명, 23 - 33세)을 대상으로 시험을 진행하였다. 머리 위치와 교합접촉면적의 관계를 알아보기 위해 시험대상은 치과용 유닛체어에 세 가지 자세(누운 자세($0^{\circ}$), 기울인 자세($45^{\circ}$), 직립 자세($90^{\circ}$))로 하여 최대 교두간 접촉위를 이용하여 악간관계기록을 채득하였다. 광조사교합분석기($BiteEye^{(R)}$)를 이용하여 교합접촉면적을 분석하였다. SPSS 25.0을 이용하여 유의수준 95%에서 통계분석을 시행하였다. 결과:머리 위치는 교합접촉면적과 유의미한 영향이 없는 것으로 나타났다(P > 0.05). 결론: 머리 위치는 교합접촉면적에 유의미한 영향이 없으므로 교합관계가 안정적이라면 최대 교두간접촉위의 악간관계 기록 채득 시 환자의 자세는 변수가 되지 않으며 광조사교합분석기를 이용한 교합접촉면적의 측정은 재료적, 용이성 측면으로 유용하다고 할 수 있다.

• Design & Manufacturing
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• 제13권4호
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• pp.1-9
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• 2019

In-mold Coating is a method that can simultaneously perform injection molding and surface coating in injection mold. The material used for coating is two-component polyurethane which is composed of polyol and isocyanate. L-type mixing head can be used to mix polyol and isocyanate uniformly, and inject them inside the mold cavity. The surface quality of the injection molded products by using in-mold coating depends on the mixing uniformity between main agent and hardener. In this study, flow analysis was performed to design a mixing head for uniform mixing of two-component polyurethane. Especially the effects of design parameters of mixing head on mixing uniformity and nozzle pressure were investigated. The parameters of mixing head were mixing chamber diameter, cleaning cylinder diameter, nozzle alignment angle in the horizontal and vertical direction, and cleaning piston position. It was found that optimal design values were mixing chamber diameter of 3.5 mm, cleaning cylinder diameter of 5.0 mm, nozzle horizontal/vertical alignment angles of 140°/160°, and cleaning piston position of 1.8 mm. The optimal values would be used to develop a two-component mixing head achieving an uniform mixing for in-mold coating.

• 한국생산제조학회지
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• 제21권3호
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• pp.401-407
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• 2012

The recent manufacturing process in the thin wafers and flat panel necessitate new approaches to reduce handling fragile and surface-sensitive damage of components. This paper presents a new pneumatic levitation for non-contact handling of parts and substrates. This levitation can achieve non-contact handling by blowing air into an air pressure pick-up head with radial passages to generate a negative pressure region. Negative pressure is caused by the radial air flow by nozzle throat and through holes connecting to the bottom region. The numerical analysis deals with the levitational motion with different design factors. The dynamic motion is examined in terms of force balance(dynamic equilibrium) occurring to the flow field between two objects. The stable equilibrium position and the safe separation distance are determined by analyzing the local pressure distribution in the fluid motion. They make considerable design factors consisting the air pressure pick-up head. As a result, in case that the safe separation distance is beyond 0.7mm, the proposed pick-up head can levitate stably at the equilibrium position. Furthermore, it can provide little effect of torque, and obtain more wide picking region according to the head size.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권3호
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• pp.180-185
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• 2012

Purpose: An accurate preoperative analysis of the patient is essential in orthognathic surgery in order to acquire superior results. In profile, the location of the chin's position may change according to the neck's inclination. This may ultimately affect the amount of surgical movement. During acquisition of cephalometric radiographs, or in supine position, there is a discrepancy in the neck's inclination. This means that there are also various discrepancies between the actual profile and the various preoperative profile images. In the clinical situation, the decision in performing genioplasty usually lies in the analysis of the patient's profile on the operating table at the final stages of orthognathic surgery. This study aims to analyze the different preoperative profile images and to compare their discrepancies. Methods: Fifty eight patients undergoing orthognathic surgery were chosen. These patients were divided into three groups according to angle's classification of malocclusion, as class I, II or III. The right profile of these patients in centric occlusion was taken in natural head position (NHP). This was set as the 'actual profile image.' Another right profile image was taken on the operating table after insertion of the nasotracheal intubation and with muscle relaxants in effect. This was also taken in centric occlusion. The angle (denoted 'A') between the soft tissue glabella-pognion and the true vertical plane was found in the above-mentioned profile images and in the cephalometric radiographs. The differences of these values were analyzed. Results: There were differences in Angle 'A' in all of the preoperative images. These values were however, not statistically significant. Conclusion: In order to gain an esthetic profile during orthognathic surgery, the NHP is shown to be the most reliable position. Images reproducing such head positions should be used in the treatment planning process.

• Journal of Korean Neurosurgical Society
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• 제61권5호
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• pp.568-573
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• 2018

Objective : Thoracic pedicles have special and specific properties. In particular, upper thoracic pedicles are positioned in craniocaudal plane. Therefore, manipulation of thoracic pedicle screws on the left side is difficult for right-handed surgeons. We recommend a new position to insert thoracic pedicle screw that will be much comfortable for spine surgeons. Methods : We retrospectively reviewed 33 patients who underwent upper thoracic pedicle screw instrumentation. In 15 patients, a total of 110 thoracic pedicle screws were inserted to the upper thoracic spine (T1-6) with classical position (anesthesiologist and monitor were placed near to patient's head. Surgeons were standing classically near to patient's body while patients were lying in prone position). In 18 patients, a total of 88 thoracic pedicle screws were inserted to the upper thoracic spine with the new standing position-surgeons stand by the head of the patient and the anesthesia monitor laterally and under patient's belt level. All the operations performed by the same senior spine surgeons with the help of C-arm. Postoperative computed tomography scans were obtained to assess the screw placement. The screw malposition and pedicle wall violations were divided and evaluated separately. Cortical penetration were measured and graded at either : 1-2 mm penetration, 2-4 mm penetration and >4 mm penetration. Results : Total 198 screws were inserted with two different standing positions. Of 198 screws 110 were in the classical positioning group and 88 were in the new positioning group. Incorrect screw placement was found in 33 screws (16.6%). The difference between total screw malposition by both standing positions were found to be statistically significant (p=0.011). The difference between total pedicle wall violations by both standing positions were found to be statistically significant (p=0.003). Conclusion : Right-handedness is a problem during the upper thoracic pedicle screw placement on the left side. Changing the surgeon's position standing near to patient's head could provide a much comfortable position to orient the craniocaudal plane of the thoracic pedicles.

• 한국생활과학회지
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• 제15권4호
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• pp.623-630
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• 2006

The purpose of this study is to do research hairdressers' knowledge of hairless head dummy's brand name, and to suggest and develop various hairless head dummy for the students who are learning hair styling in the colleges and the academies, for the hairdressers working in the beauty salons. Using only one and same kind of hairless head model is not appropriate for hairdressers and students being trained hair styling skill, because people have a variety of head shapes. Three hundred twenty nine persons who live in Iksan area are selected as subjects. The results of the study are as follow: by the analysis of subjects' knowledge of hairless head dummy's brand name, most of them didn't know it exactly. This study deduced that there is a significant relation between the utility of hairless head dummy and subjects' intention of purchasing the dummy. To put it in detail, in case of college students, there is little significant difference between them. But in case of academy students, there is. By the regression analysis, especially, in case of hairdressers working in beauty salons and academy students, four conditions did significantly matter in their purchasing the dummy: first, whether the respondents owns it, second, whether it is helpful to themselves, third, whether they have ever used foreign products and, finally, whether they have intention to purchase various hairless head dummys or not. In conclusion, it depended on each group position whether their knowledge of brand names of hairless head model affects their purchase of the dummy or not.