• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.535-542
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• 2000

The purpose of this study was to find the characteristics of the frontal natural head position(NHP) of patients with facial asymmetry, and to contribute to the diagnosis of facial asymmetry in the clinical examination of orthodontic patients. Twenty adult patients who had apparent facial asymmetry and no severe sagittal skeletal discrepancy were selected as the asymmetry group, and 21 young adults who had symmetric faces were selected as the symmetry group. Frontal cephalograms were obtained in the state of NHP using a pivot-mounted fluid level device. The degree of the menton deviation was defined as the angle between the line drawn through crista galli and anterior nasal spine and the line drawn through crista galli and menton. The following angles were measured and each of them was compared with the degree of the menton deviation one is the angle between the true vertical line and the supra-orbital line which is a tangent line to the extreme cranial point on the supra-orbital margin, and the other is the angle between the true vertical line and the cervical line drawn through the midpoint of atlas and the 4th cervical vertebra. Through the statistical analysis, following results were obtained. 1. The angle between the supra-orbital line and the true vertical line was much mote deviated from the right angle in the asymmetry group than in the symmetry group. 2. The angle between the cervical line and the true vertical line in the asymmetry group showed greater tendency than in the symmetry group, but the difference was not statistically significant. 3. In the asymmetry group, the degree of the menton deviation was positively correlated with the angle between the supraorbital line and the true vertical line. The above results suggest that racial asymmetry patients show the tendency to have the tilted NHP to compensate the deviation of menton position.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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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.

• Physical Therapy Korea
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• v.13 no.2
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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.

• Journal of KSNVE
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• v.10 no.2
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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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.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.12 no.1
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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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)

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.409-426
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• 2001

Absorbed power of the human head radiated from a 900 MHz portable phone and temperature rise are computed using FDTD(Finite-Difference Time-Domain) method. For this computation the 5 layered media for the human head modeling and the monopole antenna attached to metallic box for the portable phone are used. To reflect the real circumstances typical sizes of human heads and portable phones are considered in the calculation. The length of monopole antenna is 8.15 cm, and the output power of a phone is 600 mW. Under the predetermined model the distribution of 1 g, 10 g averaged SAR and temperature rise rate over the human head are calculated, from which it was found that the position of maximum SAR is near at the head skin surface, not deep places far into the head. The position of the highest temperature is located far from the head skin more than that of the maximum SAR occured. The averaged SAR and temperature along the distance between the head and phone are calculated according to seperation distance between the head and phone.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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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.