• 대한치과교정학회지
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• 제30권5호
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• pp.535-542
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• 2000

본 연구는 안면비대칭 환자의 natural head position(NHP)시 정면에서의 두부 또는 경추의 경사 정도를 알아봄으로써 교정환자의 임상검사시 비대칭의 진단에 도움이 되고자 시행되었다. 두드러진 전후방 골격 이상은 없으나 뚜렷한 좌우 안면비대칭을 보이는 성인 20명을 비대칭군으로, 좌우 대칭적인 외모와 비교적 정상교합을 보이는 성인 21명 을 대칭군으로 선정 한 다음 물방울 수평계를 이용하여 NHP 상태의 정모두부방사선사진을 촬영하고 투사도를 작성하였다. Crista galli와 anterior nasal spine을 연결한 선과 crista galli와 menton을 연결한 선이 이루는 각을 menton의 변위 정도로 정하고, 좌우 supra-orbital margin의 최상방점을 지나는 supra-orbital line과, 제1경추와 제4경추의 중심을 연결한 cervical line이 각각 true vertical line과 이루는 각을 계측한 다음 이들간의 상관관계를 비교 분석하여 다음과 같은 결과를 얻었다. 1. Supra-orbital line이 true vortical line과 이루는 각이 직각에서 벗어난 정도가 대칭군에 비하여 비대칭군에서 통계적으로 유의하게 크게 나타났다. 2. Cervical line이 true vertical line과 이루는 각은 통계적 유의차는 없었으나 비대칭군에서 더 큰 경향을 보였다. 3. 비대칭군에서 supra-orbital line이 true vortical line과 이루는 각이 직각에서 벗어난 정도는 menton의 변위 정도와 통계적으로 유의한 순상관관계를 보였다. 이상의 결과로 안면비대칭 환자는 menton의 변위를 보상하려는 방향으로 기울어진 NHP를 가지는 경향이 있음을 알 수 있었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.13.1-13.8
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• 2018

Background: We evaluated change in the mandibular condyle after orthognathic surgery using cone-beam computed tomography (CBCT) in patients with facial asymmetry. Methods: Thirty patients with skeletal class III malocclusion and mandibular prognathism or facial asymmetry were classified into two groups according to the amount of menton deviation (MD) from the facial midline on anteroposterior (AP) cephalogram: group A (asymmetry, MD ≥ 4 mm; n = 15) and group B (symmetry, MD < 4 mm; n = 15). Position and angle of condylar heads on the axial, sagittal, and coronal views were measured within 1 month preoperatively (T0) and postoperatively (T1) and 6 months (T2) postoperatively. Results: On axial view, both groups showed inward rotation of condylar heads at T1, but at T2, the change was gradually removed and the condylar head returned to its original position. At T1, both groups showed no AP condylar head changes on sagittal view, although downward movement of the condylar heads occurred. Then, at T2, the condylar heads tended to return to their original position. The change in distance between the two condylar heads showed that they had moved outward in both groups, causing an increase in the width between the two heads postoperatively. Analysis of all three-dimensional changes of the condylar head positions demonstrated statistically significant changes in the three different CBCT views in group B and no statistically significant changes in group A. Conclusions: There was no significant difference between the two groups in condylar head position. Because sagittal split ramus osteotomy can be performed without significant change in symmetrical and asymmetrical cases, it can be regarded as an effective method to stabilize the condylar head position in patients with skeletal class III malocclusion and mandibular prognathism or facial asymmetry.

• 한국전문물리치료학회지
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• 제13권2호
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• pp.77-84
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• 2006

Although conservative management of congenital muscular torticollis (CMT) has been well documented, relatively little is known about the response to the treatment. The purposes of this case report were to describe the use of a therapeutic approach based on motor development in physical therapy intervention for an infant with CMT and to report the result of the treatment. The patient was a 20-day-old baby boy with left CMT presenting muscular mass in the left sternocleidomastoid muscle. The angle of the lateral head tilt was 20 degrees. The size of muscular mass was 5.3 mm in ultrasonography. Intervention included ultrasonic therapy, soft tissue massage, passive and active range of motion exercises, motor developmental therapy, and parent instruction. The procedures of motor developmental therapy and changes in the amount of lateral head tilt were documented using photography. The size of the mass was decreased to .3 mm before the 5-month follow-up. The patient also maintained a midline head position in the supine position and a midline head alignment during all functional activities. A therapeutic approach based on motor development is a beneficial method for reducing an asymmetrical head and neck position, and facilitating normal development as a component of physical therapy intervention.

• 소음진동
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• 제10권2호
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• pp.269-279
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• 2000

This paper deals with the development of biomechanical model on a seat with backrest support in the vertical direction. Four kinds of biomechanical models are discussed to depict human motion. One DOF model mainly describes z-axis motion of hip, two and three DOF models describe z-axis of hip and head, and while nine DOF model suggested in this study represents more motion than the otehr model. Three kinds of experiments were executed to validate these models. The first one was to measure the acceleration of the floor and hip surface in z-axis, the back surface in x-axis, and the head in z-axis under exciter. From this measurement, the transmissiblities of each subject were obtained. The second one was the measurement of the joint position by the device having pointer and the measurement of contact position between the human body and the seat by body pressure distribution. The third one was the measurement of the seat and back cushion by dummy. The biomechanical model parameters were obtained by matching the simulated to the experimental transmissiblities at the hip, back, and head.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.140-145
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• 2002

In high-capacity disk drives with ever-growing track density, the allowable level of position error signal (PES) is becoming smaller and smaller. A substantial portion of the PES is caused by disk vibration. This can be reduced by using a head gimbal assemblies (HGAs) that do not confine the slider movement to the vertical direction to disks, but allow movement to the radial direction of disks with respect to disk vibration. Several types of HGAs are proposed for such radial motion of the slider. Experimental results show that the PES levels are reduced by the proposed HGA-design concepts.

• 치과방사선
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• 제12권1호
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• pp.63-67
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• 1982

The author modified the Aquard 100 head holder device from Denar Co. to be adequate to the Koreans and to enhance the standardization and reproducibility of the temporomandibular joint radiographs. The results were obtained as follows; 1. The projected central ray was at an angle of 25 degrees. 2. Standardization of patients head position was obtained by means of vertical and horizontal bar which were attached to the head holder. 3. Arbitrary 3 points (A.B.C.) which were on the TMJ area of dry skull were measured for the identification of reproducibility. 4. Measured distances in dry skull were as follow; A-B, 28.0±0.25, B-C 11.9±0.25 and C-A 30.4±0.21, in closed position.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.320.2-320
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• 2002

In high-capacity disk drives with ever-growing track density, the allowable level of position error signal (PES) is becoming smaller and smaller. A substantial portion of the PES is caused by disk vibration. This can be reduced by using a head gimbal assemblies (HGAs) that do not confine the slider movement to the vertical direction to disks, but allow movement to the radial direction of disks with respect to disk vibration. Several types of HGAs are proposed for such radial motion of the slider. (omitted)

• 치과방사선
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• 제17권1호
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• pp.151-162
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• 1987

The author obtained the computed tomograms around the condylar head from 10 normal subjects and 5 patients having clicking condylar head from 10 normal subjects and 5 patients having clicking sound or limitation of mouth opening by using a Hitachi-W 500. And then. the author had the axial analysis of condyle position and sagittal analysis of that after sagittal reformation on centric occlusion and 18㎜ interincisal opening. Transcranial view and submentovertex view were taken and compared with computed tomographic view. The obtained results were as follows: 1. Median angle of long axis of condylar head was 17 degrees on centric occlusion and the angles of long axis of both condylar heads were reduced symmetrically on 18㎜ interincisal opening in normal group. however. in the patient group, the affected side of condyle heads showed greater change in the angle on 18㎜ interincisal opening. 2. In the patient group, the condyle head of affected side was located superiorly to that of normal side on centric occlusion and the discrepancy of condular positional height was increased after 18㎜ interincisal opening. 3. The distances from medial pole of condylar head to triangular fossa of temporal bone were same on both right and left side in normal group, however, in the patient group, the distance of affected side was wider than that of opposite side on centric occusion and became narrower than the opposite side on 18㎜ interincisal opening. 4. The distances of posterior joint space were same on both right and left side. The distance t lateral pole 1/3 of condyle head was similar to that on transcranial view on centric occlusion in normal group. 5. The distances of posterior joint space were narrower in patient group than in normal group. 6. Conclusively, the affected condylar head of patient showed postero-latero-superior displacement on centric occlusion and larger range of rotational movement on 18㎜ interincisal opening.

• 한국전자파학회논문지
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• 제12권3호
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• pp.409-426
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• 2001

본 논문은 유한차분 시간영역 해석법(Finite-Difference Time-Domain Method)을 사용하여 900 MHz용 휴대폰으로부터 방출된 전파의 인체 두부(頭部)에 흡수된 전력량을 산출하였고, 흡수전력으로 인한 두부내의 온도 상승량을 계산하였다. 이를 위하여 인체두부를 5층 매질로 모델링하였고, 휴대폰은 금속상자에 부착된 모노폴안테나로 모델링하였다. 모델링에 사용된 인체두부와 휴대폰의 크기는 상용의 값을 사용하였다. 사용된 모노폴 안테나의 길이는 8.16 cm이고, 휴대폰의 출력은 상용 900 MHz의 600 mW을 사용하였다. 설정된 모델링하에서 인체의 위해(危害)정도를 알려주는 지수는 1 g, 10 g 평균 北 흡수율(SAR-Specific Absorption Rate)의 분포를 계산하였고 이에 따른 1g, 10 g 평균 온도 상승량을 계산하였다. 그 결과 비흡수율이 최대가 되는 지점은 인체 두부의 피부 부분이었고 최대 온도 증가 위치는 이보다 안쪽부분에서 나타났다. 인체 두부와 휴대폰의 이격거리에 따른 SAR과 온돈 상승량을 계산하였다.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.42-48
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• 2003

LPG has been a broad concern of pro-environmental alternative fuel for vehicles. Recently, the new Liquid Phase LPG Injection(LPLI) system extends the limit of power of LPG engine and gives a chance to substitute LPG engine for diesel engine of heavy duty vehicles that are the main resources of air pollution in urban area. Large bore size of heavy duty LPG engine derives a serious knock problem. To find an optimal MBT conditions, it is necessary to know how the flame develops in the combustion chamber and find where the knock positions are. In this study. the ion-probe head gasket was used to estimate the knock position. Inverse operation of the ion-probe signal provides the flame developing characteristics. The further the position is from the spark plug, the later the flame arrives and the more times knock occurs. The main factor that effects knock position is inferred a flor situation of mixed gas in the combustion chamber.