• 대한통합의학회지
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• 제5권1호
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• pp.67-74
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• 2017

Purpose : Forward head posture is typical neck disorders occur in all people. And this attitude causes a shortening and weakening of the muscles in the body. It also causes excessive extension acts as a reward. This attitude has to change if the pain occurs around the neck and shoulders, and are subjected to unusual stress. Patients with chronic neck pain associated with forward head posture was found to be the more severe the fall of the respiratory, forward head posture poor quality of much breath. The purpose of this study was to compare the effect of changes in forward head posture and neutral head posture on respiratory. Method : Forty volunteers were participated in study and divided into two groups [forward head posture group (n=20) and neutral head posture group (n=20)]. We measured cervical alignment with global postural system to find out a forward head posture. Respiratory function was measured with a SPIROVIT SP-1 equipment and we found out a forced vital capacity (FVC), forced expiratory volume at one second (FEV1) and FEV1/FVC. A pared t-test was used to determine a statistical significance for the pulmonary function variation and a independent t-test was used to determine a statistical significance in the two groups. Results : In the experimental group, FVC and FEV1 were significantly higher in the artificial neutral head posture than in the forward head posture. In the control group, FVC and FEV1 were significantly higher in the neutral head posture than in the forward head posture. FVC, FEV1, and FEV1/ FVC were significantly higher in the neutral head posture of control group than the artificial neutral head posture of experimental group and higher in the artificial forward head posture of control group than the forward head posture of experimental group. Conclusion : In conclusion, neutral head posture is considered to be an important factor in correct posture and improvement of lung function and continuous study of posture correction program for posture imbalance will be needed.

• Design & Manufacturing
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• 제10권2호
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• pp.18-23
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• 2016

Injection molded thermoplastic parts may need to be coated to facilitate paint adhesion, or to satisfy other surface property requirements, such as appearance, durability, and weather resistance. In this paper, a two-component polyurethane metering system was developed for the simultaneous injection and surface coating of a plastic substrate. The system was composed of storage tanks, feed pumps, axial piston pumps, mixing head. The tank was designed to be double-jacket structured and fabricated for polyol and isocyanate, respectively. A temperature chamber was used to maintain the material temperature to be $80^{\circ}C$ during flowing from storage tank to mixing head. Inside the chamber, feed pump, low pressure filter, high pressure pump, high pressure filter, pressure sensor, flow meter were installed. A mixing head of L-type was used for homogeneous mixing of polyol and isocyanate. Inside the mixing head, a cartridge heater and a temperature sensor were installed to control the temperature of the materials. The flow rate of axial-piston pump was controlled by using closed-loop feedback control algorithm. The input flow-rates were compared with the measured values. The output error was 6.7% for open-loop control, whereas the error was below 2.2% for closed-loop control. In addition, the pressure generated through mixing-head nozzle increased with increasing flow rate. It was found that the pressure drop between metering pump and mixing-head nozzle was almost 10 bar.

• The Journal of Korean Physical Therapy
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• 제34권5호
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• pp.212-217
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• 2022

Purpose: This study sought to investigate the effects of visual cue deprivation balance training by applying head control feedback to the balance function and the fall index in older people. Methods: The study was conducted on 26 older people at the S Hospital in Gyeongsansi. The patients were randomly divided into the experimental groupI (EGI, n=9), the experimental groupII (EGII, n=9), and the control group (CG, n=8). The three groups were trained for 30 minutes three times a week for four weeks. To assess the patients' static balance function, their limits of stability (LOS) was measured using the BioRescue system, (RM Ingenierie, France), composed of a pressure platform that can measure force in diverse ways, a computer, and a monitor. The dynamic balance function was measured using the Berg Balance Scale (BBS). Also, the fall index was measured to evaluate the risk of falling. A paired t-test was performed to compare pre- and post-training performance within the groups. One-way ANOVA was performed for comparing the three groups. A post hoc least significant difference (LSD) test was also performed. Results: The results of the LOS showed a significant difference after training in the EGI and EGII groups (p<0.05). As a result of the difference between the three groups, there was a significant difference after training (p<0.05). The results of the BBS showed a significant difference after training in the EGI group (p<0.05). As a result of the difference between the three groups, there was a significant difference after training (p<0.05). Conclusion: Visual cue deprivation balance training applying head control feedback is effective in improving the dynamic balance function in older people. It is also necessary to constantly maintain the head orientation by feedback and to properly control the head movement.

• 한국축산식품학회지
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• 제36권4호
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• pp.445-451
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• 2016

The effect of reducing pork meat concentrations from 50% to 30% and replacing it with up to 20% pork head meat on chemical composition, cooking characteristics, physicochemical and textural properties, apparent viscosity, and sensory characteristics of frankfurters was determined. The highest moisture content in frankfurters was found in the control and T1 (frankfurter with 45% pork meat + 5% pork head). Protein and fat contents in frankfurters with pork head meat added were significantly (p<0.05) higher than those in the control. When the concentration of pork head meat was increased from 0% to 20%, cooking loss, total expressible fluid separation, fat separation, and pH of frankfurters were increased, while the lightness, redness, yellowness, and apparent viscosity of frankfurters were decreased. Ash contents, cohesiveness, color, and tenderness of sensory characteristics of frankfurters added with different amounts of pork meat or pork head meat were not significantly (p>0.05) different from those of the control or there treatments. Frankfurters in T4 (frankfurter with 30% pork meat + 20% pork head) had the lowest (p<0.05) hardness and gumminess. The hardness and gumminess of frankfurters in other treatments were not significantly different (p>0.05) from that in the control. Frankfurters with higher pork head meat concentrations had lower flavor, juiciness, and overall acceptability scores. Therefore, replacing pork meat with pork head meat in the formulation could successfully produce results similar to those of control frankfurters. The best results were obtained when 10% pork head meat was used to replace pork meat.

• 대한물리의학회지
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• 제14권1호
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• pp.15-23
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• 2019

PURPOSE: This study was conducted to investigate the effects of the myofascial meridians release technique on pain and postural control of college students with forward head posture and to compare the intervention effects of the Grastone massage and the Rollfing massage. METHODS: Thirty subjects with forward head posture were randomly and equally allocated to experimental group I (myofascial meridians release technique using Grastone massage, n=15) or experimental group II (myofascial meridians release using Rollfing massage, n=15). All subjects underwent 30 minutes of different myofascial meridians release techniques in addition to general physical therapy (hot pack: 15 min, interferential current therapy: 15 min, ultra sound: 5 min) three times a week for a total of 6 weeks. Outcome was measured before and after 4 weeks of intervention. RESULTS: In both groups, the numerical rating scale of pain was significantly decreased after intervention, with experimental group I showing a greater decrease than experimental group II. The neck disability index decreased significantly after intervention in both groups, with experimental group I showing a significantly greater decrease than the controls. The distance of the head forward displacement did not differ significantly between the two groups (p>.05). CONCLUSION: This study suggests that the Grastone method combined with the myofascial meridians release technique is a more effective intervention for improvement of pain and postural control in adults with moderate forward head posture.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.303-312
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• 2010

This paper introduces the upper stage attitude control system of KSLV-I, which is the first space launch vehicle in Korea. The KSLV-I upper stage attitude control system consists of two electro-hydraulic actuators and a reaction control system using cold nitrogen gas. A proportional, derivative, and integral controller is designed for the electro-hydraulic thrust vectoring system, and Schmidt trigger ON/OFF controllers are designed for the reaction control system. Each attitude controller is designed to have enough stability margins. The stability and performance of KSLV-I upper stage attitude control system is verified via hardware in the loop tests. Hardware in the loop tests are accomplished for perturbed flight conditions as well as nominal flight condition. The test results show that the attitude control loop of KSLV-I upper stage is very stable and the attitude controllers perform well for all flight conditions. Attitude controllers designed in this paper have been successfully applied to the first flight of KSLV-I on August 25, 2009. The flight test results show that all attitude controllers of the KSLV-I upper stage performed well and satisfied the accuracy specifications even during abnormal flight conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7045-7047
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• 2015

Background: Mean platelet volume (MPV) is a marker which has been investigated in many cancers but data for head and neck lesions are limited. We aimed to study the MPV levels in head and neck cancers as a diagnostic marker. Materials and Methods: A total of 96 head and neck cancer patients and 31 control patients who did not meet exclusion criteria were enrolled in the study. The cancer locations, the platelet and MPV levels at the first diagnosis time were collected. Results: The head and neck cancer location distribution between these patients was 2 (2.1%) buccal, 9 (9.4%) tongue, 6 (6.3) lip, 1 (1%) gingiva, 1 (1%) hypopharynx, 1 (1%) ear, 58 (60.4%) larynx, 2 (2.1%) maxilla, 2 (2.1%) nasal, 1 (1%) nasopharynx, 2 (2.1%) palatal, 3 (3.1%) primary unknown, 1 (1%) retromolar, 1 (1%) thyroid, 2 (2.1%) tonsil, and 4 (4.2%) salivary gland. MPV levels were significantly different between cancer and control group (p=0.002). The cut-off point for MPV predicting head and neck cancer is >10 fL (sensitivity=55.21, specificity=87.10). Conclusions: MPV level increase, a readily assessable parameter which does not bring extra costs can warn us regarding head and neck cancer risk.

• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.202-205
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• 2010

When we render 3D sound images using headphones or speakers, the main key of this technology is the Head-related transfer function (HRTF) database. Even though there are various HRTF databases, they have some drawbacks such as detrimental effects caused by imperfect measuring environment and insufficient measurement points. Moreover there is no database with Korean subjects. We are planning to develop the HRTF database for Korean. As a first step to establish the HRTF database aimed at Korean, the new HRTF measurement system with minimized aforementioned drawbacks is designed. In this paper, the newly designed HRTF measurement system is introduced and the overall effects caused by the diffraction of the apparatus, especially the headrest and backrest of the chair, are analyzed. The backrest of the chair does not distort the HRTFs significantly while the headrest makes significant distortion on the HRTFs and it could have significant effects on directional perception. We determined acceptable head rotation angle and head position of the subject for accurate HRTF measurement based on the experiments with B&K HATS. We conclude that the 3 degrees of the head rotation and the 1.5cm front/back/left/right shift of the head do not distort the HRTFs significantly.

• The Journal of Korean Physical Therapy
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• 제31권6호
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• pp.351-357
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• 2019

Purpose: This study sought to investigate the effects of the McKenzie exercise program on forward head posture and respiratory function. Methods: Thirty adult men and women with forward head posture, aged 20-29 years, were randomly assigned to the experimental group (N=15) or the control group (N=15). Subjects in the experimental group performed the McKenzie exercises three times a week for four weeks, while subjects in the control group did not receive any intervention. Craniovertebral angle (CVA) was measured to quantify forward head posture, and forced vital capacity (FVC), FVC % predicted, forced expiratory volume at one second (FEV₁), and FEV₁ % predicted were measured to determine changes in respiratory function. The Mann-Whitney U-test was used to analyze pre-test differences in forward head posture and respiratory function between the two groups, and the Wilcoxon signed-rank test was used to analyze differences in forward head posture and respiratory function within the groups before and after intervention. The significance level (α) was set to 0.05. Results: A comparison of pre- and post-test measures showed that CVA significantly increased in the experimental group (p=0.001) denoting postural improvement, whereas no significant difference was found in the control group (p=0.053). All respiratory measures, i.e.,FVC, FVC %pred, FEV₁, and FEV₁ %pred, were significantly improved in the experimental group, whereas there were no significant differences in the control group. Conclusions: McKenzie exercise can be effective in improving forward head posture and respiratory function.

• The Journal of the Acoustical Society of Korea
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• 제24권3E호
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• pp.115-122
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• 2005

Two twin microphones may produce particular patterns of binaural directivity by time delays between twin microphones. The boundary element method (BEM) was used for the simulation of the sound pressure field around the head model in order to quantify the acoustic head effect. The sound pressure onto the microphone was calculated by the BEM to an incident sound pressure. Then a planar directivity pattern was formed by four sound pressure signals from four microphones. The optimal binaural directivity pattern may be achieved by adjusting time delays at each frequency while maintaining the forward beam pattern is relatively bigger than the backward beam pattern.