• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.693-705
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• 1993

The purpose of this study was to investigate the functional adaptation of the tongue, the hyoid bone, the digastric muscle and the upper airway and the variables predicting postoperative stability following orthognathic surgery in patients with mandibular prognathism. 18 patients were selected(8 men and 10 women) for this study, who had received orthognathic surgery. Their lateral cephalograms, those were taken preoperatively, immediate postoperatively and over 6 months follow-up, were traced and analysed. The results were as follows : 1. The downward displacement of the hyoid bone and extended head posture were recognized, right after operation. Statistically significant correlations were found between the changes of the mandibular position and the digastric muscle and the change of head posture during operation. 2. The tongue was displaced downward following the hyoid displacement postoperatively. Statistically significant correlations were found between the change of the mandibular position and the change of the distance of the tongue and hard palate, and between the change of head posture and the changes of the upper airway sizes, the digastric muscle and the hyoid position during over 6 month's follow-up. 3. The change of the distance of the tongue and hard palate was the most significant factor for prognosis during over 6 month's follow-up. 4. There were no variables before operation to predict the postoperative stability and the constriction of the upper airway.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.521-527
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• 2002

This paper presents a dynamic modeling and a robust PID controller design process for the wire bonder head assembly. For the modeling elements, the system is divided into electrical system, magnetic system, and mechanical system. Each system is modeled by using the bond graph method. The PID controller is used for high speed/high accuracy position control of the wire bonder assembly. The Taguchi method is used to evaluate the more robust PID gain combinations than conventional one. This study makes use of an L18 array with three parameters varied on three levels. Computer simulations and experimental results show that the designed PID controller provides more improved signal to noise ratio and reduced sensitivity than the conventional PID controller.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.23-28
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• 2005

This paper investigates the effects of disk thickness and Pemto slider on PES(position error signal) for high TPI(track per inch) drives above 150kTPI at early stage of their development. In order to reduce the disk flutter which becomes a dominant contributor to the TMR, the thicker disks with both 63 and 69mi1 have been used. Also, PES of a Pemto slider with thinner thickness than Pico slider has been estimated to decrease the conversion factor of disk motion in axial direction to head off-track motion. A frequency-domain PES estimation and prediction tool has been developed via measurement of disk flutter and HSA(head stack assembly) forced vibration. It has been validated by the measured PES in drive level. Based on the model and measurement of disk flutter, PES of a drive with the thicker disk and Pemto slider is predicted and their impact is investigated.

• Physical Therapy Korea
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• v.5 no.3
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• pp.48-55
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• 1998

The purpose of this study was to identify vital capacity (VC) in relation to the changing position of 19 patients with spinal cord injury (SCI) and 20 normal controls. Among the 19 SCI patients, there were 9 quadriplegics and 10 paraplegics. The vital capacity was measured in each subject during sitting, standing, lying, and head down position of 30 degrees. The data were analysed by the Kruskal-Wallis test, Mann-Whitney test, and Wilcoxon signed rank test. For the SCI, significant difference of VC accoring to the 4 positions between quadriplegics and paraplegics. In the control group, significant difference of VC according to the 4 positions. In 4 positions the VC of men were significantly larger than that of women between two groups. No statistical significant difference was shown in VC by the postural change between quadriplegics and paraplegics.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.31 no.1
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• pp.31-34
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• 2020

Tracheostomy is considered as a first treatment, when oral intubation seems to be difficult in patient who present severe upper airway obstruction. Generally, tracheostomy is performed in supine position. But if airway obstruction is severe enough to cause dyspnea, low oxygen saturation and inability to maintain supine position, tracheostomy should be performed in sitting position. The authors report a case of successful tracheostomy using high flow nasal cannula which help to maintain stable oxygen saturation and respiration in patients with laryngeal cancer.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.145-150
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• 2020

Forward head posture is one of the most recognized types of poor head and neck alignment. Poor head and neck alignment posture is a major contributor to compromised balance and neck pain, due to abnormal joint position sense and proprioception. Kinesio taping is an intervention method used clinically for the management of pain. Kinesio taping may produce its effects through pain reduction, stimulation of blood circulation, induction of muscle relaxation which provides correction of joint position, and providing stability to the muscles and joints without limiting the range of motion. Many studies have proved that kinesio taping has positive effects on the reduction of pain and improves alignment, on the other hand, some studies have not found. Kinesio taping may provide immediate pain relief and improved alignment following the application, but there is insufficient evidence to support sustained relief beyond that time and they recommended future studies to examine the benefits of kinesio taping as this would have a greater value in clinical practice. Therefore, this study is to investigate the effects of kinesio taping on the alignment of head posture and dynamic balance ability in people with forward head posture.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.173-181
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• 2021

Purpose : The purpose of this study is to compare muscle activity after applying two muscle energy techniques (MET) to subjects with forward head posture to see if the post isometric relaxation (PIR) technique is more effective than the reciprocal inhibition (RI) technique. Methods : The muscle activity was measured using EMG after applying the PIR and RI techniques to 30 adults at K College. Subjects were selected for forward head posture whose ear center was 2.5 ㎝ front of the center of the shoulder. EMG equipment was used to measure muscle activity, and the measurement sites were measured in cervical flexor and extensor muscles. The experiment period was performed once a week for a total of two weeks, and after the pre-measurement was performed for 5 minutes PIR and RI exercise. In the PIR technique, the head is tilted back in a sitting position, and the experimenter applies resistance with the same force for 7~10 seconds and repeats 3-5 times after rest. In the RI technique, in a sitting position, the subject gives the force to bend the head forward, and the experimenter applies resistance with the same force for 7 to 10 seconds, and repeats 3 to 5 times after rest. Results : The result is same as the following. In the comparison of muscle activity, there was a significant decrease in both PIR and RI at 1 and 2 weeks. And there was a greater decrease in muscle activity in PIR. There was no difference in the comparison of decrease in muscle activity at 1 week and 2 week. Conclusion : Both PRI and RI can be said to be effective in improving the function of the forward head posture in the neck muscles. Therefore, the selection of the two techniques in clinical practice should be appropriately performed under the judgment of experts according to the patient's situation.

• The Journal of Korean Physical Therapy
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• v.25 no.4
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• pp.217-223
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• 2013

Purpose: This study was to investigate whether the two different head postures, natural and ideal head posture, affect head/shoulder posture and muscle activity. Methods: Thirty healthy subjects with the forward head and round shoulder posture were participated in this study. This study utilized a within-subjects design with subjects being positioned into two sitting positions: natural head posture (NHP) and ideal head posture (IHP). Forward head angle (FHA) and forward shoulder angle (FSA) of each subject were measured for assessing the head/shoulder posture and muscle activities of upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) during the forward overhead reaching. Results: There were significant increases in both FHA and FSA after taking IHP, which showed greater angles than in taking NHP. In change of muscle activities, there were significant decreases in both LT and SA after taking IHP, which showed lower activities than in taking a NHP, whereas there was no significant change in UT. Conclusion: These findings demonstrate that postural alterations associated with forward head and rounded shoulder postures could alter scapular kinetics and muscle activity during the forward overhead reaching.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1009-1013
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• 2007

To do a HRTF customization, researchers used a spherical head model for modeling the head block of structural modeling of HRTF, which is the one of the technique for HRTF customization, because of its simplicity. In this paper, an analytic spheroidal HRTF caused by an incident point source will be introduced. Using proposed spheroidal HRTF, near-field HRTF customization can be applicable through a structural modeling of HRTF. To see the necessity of sheroidal head model, comparison of two analytic solutions, which are classical spherical HRTF and proposed spheroidal HRTF, will be shown. On the view point of ITD, optimal head model which matches with the measured ITD of KEMAR HRTF can be obtained. ITD results show that there are only slight differences between spherical and spheroidal head model. Magnitude comparison is made by constructing head model using measured head size. Although magnitude comparison is not studied between optimal models, the results of 24 of 36 subjects are shown that spheroidal head model matches notch frequency pattern of measured HRTF better than those of spherical one, where the sound source is at contralateral position.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.99-105
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• 2004

The car seat head restraint is used for neck injury(whiplash injury) prevention in rear end impacts. The purpose of this study was to evaluate the seat head restraints for the total number of 34 domestic cars. H-POINT machine and HRMD(head restraint measuring device) were applied to measure backset(the distance between head and seat head restraint) and height(height gap between head and seat head restraint). For tendency study of driver's head position, we took the 320 driver's pictures in the street. As results, There were only five percent drivers in good and acceptable zone. For car seat head restraint system, the results was 9 cars for good zone, 10 cars for acceptable zone, 9 cars for marginal zone and 6 cars for poor zone were evaluated. For a precise evaluation the of whiplash injury, detailed FE neck model will be developed and the clinical database should be constructed for model validation.