• International Journal of Aeronautical and Space Sciences
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• v.11 no.3
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• pp.184-192
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• 2010

In this paper, an initial fine alignment algorithm, which is developed for the strap-down inertial navigation systems of satellite launch vehicles, is considered. For fast and accurate alignment, a simple closed-loop estimation algorithm using a proportional-integral controller is introduced. Through computer simulation for the sway condition in the launch pad, it is shown that a simple filter structure can guarantee fast computational speed that is adequate for real-time implementation as well as the required alignment accuracy and robustness. In addition, its implementation results are presented for the Naro-1 flight test.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.446-453
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• 2022

Objective: The popularization of smartphones can lead to abnormal cervical alignment in university students. The aim of this study was to investigate the relationship among smartphone screen time, cervical alignment, and muscle function in university students. Design: Cross-sectional study. Methods: Seventy-five university students participated in the study. They completed the evaluation of cervical alignment and muscle function, such as handgrip strength, proprioception, and muscle quality (tone, stiffness, and relaxation time). All participants recorded their general characteristics and individual smartphone screen time before the evaluation. They were evaluated craniovertebral angle (CVA) using smartphone application (angle meter 360) for measuring cervical alignment. The muscle function was assessed using a digital hand-held dynamometer, dual inclinometer, and MyotonPRO device. Results: Of all participants, twenty-five university students had forward head posture (CVA<49°, 33.33%). Independent t-test revealed that there were significant differences on smartphone screen time, muscle stiffness, and muscle relaxation between the participants with and without forward head posture (p<0.05). There were significant correlations between the smartphone screen time and the CVA, muscle tone, and muscle relaxation (r=-0.493, 0.250, and -0.500, respectively). Conclusions: The results indicate that the university students with forward head posture had high smartphone screen time and muscle stiffness compared to the students without forward head posture, and smartphone screen time might be associated with cervical alignment and muscle quality.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.2
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• pp.81-92
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• 2013

Purpose : This research was carried out to find how neck exercise program combined with self stretching and muscle strengthening program influences on smart phone addicts with forward head posture. Methods : The subjects of this study were 20 smart phone-addicts with forward head posture and we divided them into 2 groups. The experimental group(10 people) participated in neck exercise program as a intervention for 3 months and the control group(the other 10 people) didn't participate in neck exercise program. Neck exercise program were composed of self stretching and muscle strengthening program. Then we measured cervical alignment with GPS(Global Posture System) and evaluated balance ability with Balance Master ver 7.0 systems. Results : The result were as follows. 1. After the intervention, experimental group were significantly more closed to normal cervical alignment than control group. 2. After the intervention, experimental group increased in dynamic balance ability a little more than control group. Conclusion : Neck exercise program seems to get cervical alignment better and improve balance ability.

• Korean Journal of Applied Biomechanics
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• v.32 no.4
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• pp.147-152
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• 2022

Objective: The purpose of this study was to analyze the effects of club head and golf ball kinematics and body alignment according to the swing plane during golf driver swing. Method: Sixteen college golfers participated in this study. Kinematic data of the club head and golf ball were collected using golf swing analysis system (Trackman Ver. 3e). The body alignment variables were collected using 8 motion capture system. An Independent samples t-test was used for comparison between the Out-to-In group and In-to-Out group, and the statistical significance level was set at .05. Results: For the club head related variables, club path and club face angle showed higher values in Out-to-In swing plane than In-to-Out swing plane. For the kinematic variables of the golf ball, the total distance showed a higher value in the In-to-Out swing plane than that of the Out-to-In swing plane. For the body alignment, the In-to-Out swing plane showed higher values than the Out-to-In swing plane for the pelvis rotation angle and trunk rotation angle. Conclusion: This study suggest that it would be more effective to use the In-to-Out swing plane for increasing the total distance during the golf driver swing.

• 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.

• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.386-392
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• 2013

Purpose: This study aimed to verify the impact of the time that the sitting posture is maintained on changes in muscle performance and head alignment. Methods: The subjects of this study were healthy adults aged between 20 and 30 years. Ninety-three subjects participated in this study (male: 57, female: 36). The subjects were divided into a one-hour group, a two-hour group, and a three-hour group. All the subjects adjusted the height of their chair to a comfortable position and then seat for one, two, or over three hours. Both prior to and after the experiment, the muscle performance (muscle strength, endurance, and flexibility) of the subjects was measured. Results: In the 2-hours and 3-hour group, muscle strength, flexibility and endurance reduced significantly before and after the study, and the head alignment significantly changed. Conclusion: Thease findings showed that sitting continuously for longer than two hours decreases muscle strength, endurance, and flexibility. A flexed posture affects the muscle performance of the lumbar region and may result in problematic postures, such as a forward head position.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.5 s.170
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• pp.80-86
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• 2005

Optical performance evaluation results and an interference fringe pattern analysis of alignment errors for an optical head of a near-field receding (NFR) system are presented. The focusing unit is an optical head of a NFR system and is composed of a solid immersion lens (SIL) and an objective lens (OL). Generally, the size of the focusing unit is smaller than that of the conventional optical recording head. Hence there are difficulties to assemble the small focusing unit precisely. We composed an evaluation system with an interferometer and evaluated some focusing unit samples aligned and assembled by manual and present the obtained results. Using the conventional optical tool, Code V, a tolerance analysis of the alignment error between the SIL and the objective lens and an interference pattern analysis for the assembly error are executed. Then, through an analysis of the simulation results, the conceptual auto-alignment methodology using a neural network approach is considered.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.2
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• pp.1513-1516
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• 2018

The purpose of this study was to identify the effect of upper thoracic mobilization on cervical alignment in stroke patients with forward head posture. The subject's of this study were two stroke patients with forward head posture and a cervical curve angle (four-line Cobb's method; FLCM) less than $40^{\circ}$. The intervention, central posterior-anterior (PA) mobilization, was applied to the T1-T4 vertebrae (upper thoracic spine) following the Maitland concept. This mobilization was applied three times per week for four weeks. In the results, the cervical curve angle (FLCM) increased for both subject 1 and 2. However, Jochumsen method score was decreased in subject 1, while it was increased in subject 2. These results demonstrate that upper thoracic mobilization had the positive effect on the cervical curve angle but not on Jochumsen method score. These findings suggest that PA mobilization on the upper thoracic spine could correct cervical curve angle measured by FLMC in stroke patients with FHP.

• Physical Therapy Rehabilitation Science
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• v.11 no.2
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• pp.189-197
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• 2022

Objective: The purpose of this study was to investigate the effect of a lower trapezius strengthening exercise program on an unstable support surface on pain, neck dysfunction, psychosocial factors, and postural alignment in neck pain patients with forward head posture. Design: A randomized controlled trial Methods: A total of 36 neck pain patients participated in this study. Screening tests were performed and assigned to experimental group (n=18) and control group (n=18) using randomization program. Both groups performed the lower trapezius strengthening exercise program. In addition, in the experimental group, an exercise program for lower trapezius muscle strengthening was performed on an unstable support surface. All interventions were performed 3 times a week, for a total of 5 weeks. quadruple visual analogue scale (QVAS), neck disability index (NDI), short form (SF)-12, and postural alignment were measured before and after the intervention to compare their effectiveness. Results: Both groups showed significant differences in QVAS, NDI, SF-12, and postural alignment before and after intervention (p<0.05). In addition, the experimental group showed significant differences in NDI and postural alignment compared to the control group (p<0.05). Conclusions: The lower trapezius strengthening exercise program on unstable support surfaces is an effective intervention method with clinical significance in improving neck disability and postural alignment in patients with neck pain with forward head posture.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.265-272
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• 2019

Purpose : Excessive computer use frequently results in musculoskeletal disorders of the neck and shoulder such as forward head posture (FHP). The purpose of this study was to investigate effects of neck and shoulder exercise program on spino-pelvic alignment and the correlation between change in head and neck posture and spino-pelvic alignment in FHP. Methods : The study included 44 participants with FHP. The participants performed the exercise for correction of FHP 2-3 times a week for 4 weeks. We examined whole spine X-ray images in the lateral standing position with both arms crossed. We measured anterior head translation distance (AHT), craniovertebral angle (CVA), cervical lordosis (CL), thoracic kyphosis (TK), lumbosacral lordosis (LSL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) of the subjects. The association between change in AHT and each spino-pelvic parameter was also subjected to Pearson's correlation coefficient analysis. Results : There were statistically significant differences before and after exercise in the parameters of AHT, CVA, and SS (p<.05). Significant negative correlation was observed between the change in AHT and CVA (r=-.768, p<.001), and CL (r=-.388, p<.05). There was significant positive correlation between the change in AHT and SS (r=.328, p<.05), and PI (r=.333, p<.05). However, no significant correlation was observed in change in AHT with that of TK, LSL, and PT. Conclusion : Based on the above results, we conclude that there is a relationship between change in AHT, which is a parameter associated with forward displacement of the head, and that of CVA, CL, SS, and PI after exercise in cases of FHP.