• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.543-552
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• 2000

The purposes of this study were to evaluate the reproducibility of posteroanterior(PA) cephalograms obtained by two methods, the Head Posture Aligner(HPA) method in natural head posture and the conventional method(operator-guided method), and to compare the vertical rotational differences of the head Posture between lateral and PA cephalograms according to the method. The sample was consisted of 30 adults. At first day, a PA cephalogram and a lateral cephalogram were obtained from each subject by two methods to investigate the difference of vertical rotational posture between lateral and PA cephalograms. Two weeks later, another PA cephalogram was obtained using each method to evaluate the reproducibility of head posture. Five height measurements and nine width measurements were used in the paired t-test to compare the reproducibility of the PA cephalometric measurements between two methods. The differences of vertical rotational posture between lateral and PA cephalograms were calculated from a computer program and compared according to the method used, and following results were obtained. 1. Height measurements obtained by operator-guided method showed significant differences according to the time interval and revealed low reproducibility. 2. Height measurements obtained by HPA method did not show significant differences according to the time interval and presented high reproducibility. 3. In the comparison of width measurement, two methods did not show distinct differences in reproducibility. 4. The difference of vertical rotational posture between lateral and PA cephalograms showed $0.8^{\circ}$ in the HPA method, more less than $2.5^{\circ}$ in the operator-guided method. The results of the present study suggest that the HPA may be helpful in the PA cephalometric radiography in terms of reproducibility.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.51.3-51
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• 2002

3D sound user often finds the results that the sound image appear to originate either inside, or close to, the head when he uses headphone-based binaural system. This phenomenon is called in-head localization(IHL). The main factors were chosen to evaluate externalization performance : individualized HRTFs, near-field HRTF characteristics and reverberation. Direct comparison was conducted among them, especially two factors\ulcorner reverberation and near-field HRTFs.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1268-1278
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• 2004

Measurement of noise is not only to know the information of acoustic pressure but to assess human response to noise. To find human response to transportation noise through the laboratory study we have to measure and reproduce noise. The method of noise reproduction is largely divided into monaural and binaural techniques. But human fundamentally hears sound through both ears, referred as binaural hearing. Binaural signal is different from monaural signal because it includes more information of physical phenomena like acoustical reflection, diffraction and refraction. Especially head and pinna play an important role in perceiving change of signal origin. So, the amplitude of binaural signal is higher than that of monaural signal and spectrum of both signals is discriminated. Most of assessment and regulation of transportation noise are, however, based on monaural measurement techniques. The quantitative difference between monaural and binaural measurement is investigated in this study. Comparison on several transportation noisesshows defect of information in monaural measurements.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.135-144
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• 2021

Purpose : The purpose of this study was to investigate the effect of 2 weeks of backward walking exercise (BWE) on cervical angle and gait parameters in college students with forward head posture. Methods : Fifteen subjects participated in the experiment. All the participants had a craniovertebral angle (CVA) of 55 degrees or less. The purpose of the study was explained to all the subjects prior to participation, and volunteered to take part in the study. A camera capable of taking pictures of the lateral plane was installed at a distance of 1.5 meters from each subject. Images of forward head posture were obtained before and after performing the BWE, and the CVA and craniorotational angle (CRA) were compared pre- versus post exercise. Foot pressure and gait parameters (step length of left and right, stride length, stance of left and right, swing of left and right, step time of left and right, and stride time) were measured using a rehabilitation treadmill. The subjects performed the BWE for 2 weeks. The exercise program consisted of a 5-minute warm-up exercise, 20-minute main exercise, and 5-minute cool-down exercise. In the main exercise, the treadmill speed was set to 2.4 km/h in the first week and 3.4 km/h in the second week. A paired t test was used to compare the CVA and CRA and gait parameters before and after the exercise. Results : Comparison of the CVA and CRA before and after the BWE revealed a significant difference post exercise, with a marked improvement in forward head posture after the exercise (p<.05). Conclusion : Based on the results of this study, the BWE is considered to be an effective exercise for the forward head posture. Also, additional research is needed to shed light on the impact of the BWE on gait parameters.

• Korean Journal of Head & Neck Oncology
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• v.14 no.1
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• pp.3-14
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• 1998

Objectives: Many complicated problems exist in establishing head and neck cancer(HNCa) patient registry system. In this study, a newly devised and simplified approach named as 'Single Sheet Multiple Event System' was compared with a conventional approach named as 'Multiple Sheet System'. Material and Method: According to several kinds of registry sheets in the two systems, data were collected from 486 patients with HNCa diagnosed at Department of Otolaryngology, Seoul National University Hospital from 1979 through 1994. Results: The new system produced more simple and efficient data retrieval. Conclusion: It could make the implementation of HNCa patient registry system more simple and efficient.

• Journal of International Academy of Physical Therapy Research
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• v.7 no.1
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• pp.956-964
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• 2016

The purpose of this study was to identify the effects of continuous muscle strengthening applied to the antagonist of the sternocleidomatoid, upper trapezius, and pectoralis major, which are the shortened muscles of forward head posture(FHP) subjects, and Evjenth-Hamberg stretching(EHS) applied to the shortened muscles on changes in pressure pain threshold(PPT). Twenty subjects were divided into the continuous antagonist strengthening(CAS) group(n=10) and the EHS group(n=10), and each group performed its respective exercise three times a week for a six week period. The results were as follows: The comparison of changes in PPT within each group before and after the treatment showed a statistically significant difference(p<.05) according to the treatment period and a statistically significant difference according to the treatment period and method(p<.05). While the comparison of the tests of between subjects effects between the groups did not show a statistically significant difference, the CAS group exhibited better effects. The above results suggest that the combined application of CAS and EHS generates better effects on changes in PPT than the single application of EHS. Given that stretching and muscle strengthening exercises even for the short research period of six weeks could change the PPT, continuous exercises and a correct postural habit for a longer period of time are likely to help prevent chronic pain and correct FHP.

• IE interfaces
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• v.15 no.2
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• pp.199-208
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• 2002

This study was performed to measure the various dimensions of the head and face for Korean adults. Three hundred and eighteen males and two hundred and sixty females, age ranged 18 to 60, participated for this study. Thirty-six dimensions were selected to measure. Subjects were divided into three age groups - 18 to 29, 30 to 39, and 40 to 60 - for each sex. The data were analyzed ta see the differences between the age groups and sex using SAS program. Also, the results of this study were compared to the data of Japanese and US. army. The results showed that the 'ear length', 'bigonial breadth' and 'bitragion submandibular arc' increased as the age increased(p<0.01). However, not much of differences were shown between the age groups in most of other dimensions. Males were significantly bigger than females in every dimensions. The comparison between Korea and Japanese showed significant differences in many dimensions. Due to this reason, it is considered that more caution has to be exercised in using Japanese data for the Korean. The Americans showed to be significantly bigger than Korean in most dimensions. It showed that Koreans have more roundish face and wider nose ridge than Americans. The results of this study can be used to design the products that related to the head and face.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.581-590
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• 1991

This study was carried out for the comparison of the head postures between mouth breathers and normal nasal breathers. For this purpose, a test group of 28 mouth breathers, between the ages of 8 to 12 years old and a control group of 25 nasal breathers were used. Following results were obtained after comparing the craniofacial and craniocervical angulations to the True Vertical line. 1. In the comparisions relating to the True Vertical Line, results were obtained using four items; NSL/VER, FH/VER, NL/VER, PMV/VER. Variations were observed in all the items and the craniofacial angulations in the mouth breathers group showed more superior position compared to the control group. 2. In the comparisions relating to the craniocervical angulations, results were obtained using four items; NSL/OPT, FH/OPT, NL/OPT, PMV/OPT. Variations between the two groups were observed only in the PMV/OPT item and the mouth breather group showed more craniocervical angulations compared to the control group.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.341-350
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• 2005

The Purpose of this study was to compare the degree of vortical head rotation and to evaluate the reproducibility of natural Head posture (NHP) according to two guiding methods, the head posture aligner (HPA) method and the solf balance posture (SBP) method. The subjects consisted of 30 adults. On the first day. lateral and frontal cephalometric radiographs were obtained through the two guiding methods. One mouth later. lateral and frontal cephalometric radiographs were obtained again through both guiding methods. The degrees of vertical head rotation of both guiding methods were compared and the reproducibility was evaluated for each guiding method. A comparison of the degrees of vortical head rotation for the two methods revealed that the vertical head posture was lower in the SBP method than in the HPA method by an average of $2.79^{\circ}$. All measurements obtained using the HPA and SBP methods with a time interval of one north did not show any significant difierence in lateral and frortal cephalometric radiographs. The results of the present study suggest that the SBP method may be used as an alternative to the HPA method in case the HPA method can not be applied.

• Korean Journal of Bronchoesophagology
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• v.17 no.2
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• pp.104-107
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• 2011

Background and Objectives Scope classification is designed to classify acute epiglottitis according to laryngoscopic findings. There is no report about the utility of classification; the difference between the diagnosis and the prognosis by the Scope classification was not found. The aim of this study was to evaluate the utility of Scope classification in patients with acute epiglottitis. Subject and Method 127 patients who had been admitted to our hospital were diagnosed with acute epiglottitis. The patients were classified by the Scope classification. We compared demographic characteristics, clinical symptoms and signs, laboratory findings, and clinical course among the patient groups and divided the results according to the Scope classification. Results There are no significant differences among the groups in demographic characteristics, clinical symptoms and signs, laboratory findings, and clinical course. Conclusion The Scope classification of acute epiglottitis does not seem to be a method to evaluate the severity of acute epiglottitis. Thus, we need to develop multidisciplinary approaches for acute epiglottitis.