• The Journal of Korean Physical Therapy
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• 제33권5호
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• pp.217-223
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• 2021

Purpose: This study sought to identify the effects of coordinative locomotor training (CLT) using elastic bands on the flexibility and body alignment of right-handed baseball players in elementary school. Methods: The subjects were 20 instructed right-handed baseball players in elementary school. They were classified into the experimental group with 10 players (n=10) to be given coordinative locomotor training using elastic bands and the control group with 10 players (n=10). Flexibility was measured by the sit and reach exercise. Body alignment was measured using formetric 4D method to measure the trunk imbalance angle (TI), trunk torsion angle (TT), pelvic tilt angle (PTi), pelvic torsion angle (PTo), pelvic rotation angle (PR), kyphotic angle (Ky), and lordotic angle (Lo). Results: There was a significant increase in the flexibility within the experimental group (p<0.05). after the intervention. There was also a significant increase in the difference between the experimental group and the control group (p<0.05). There was a significant decrease in PR during body alignment in the experimental group after intervention (p<0.05). An analysis of the differences between groups showed a significant decrease in the PR of the experimental group compared to the control group (p<0.05). Conclusion: These findings show that coordinative locomotor training using elastic bands would be effective for enhancing the flexibility and pelvic rotation of elementary school right-handed baseball players.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.320-325
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• 1999

An absolute type shaft encoder which utilized moire fringe will be presented in this paper. Linear moire fringe is commonly used to measure the displacement of the linear motion. However, an absolute encoder which measure the rotation angle of a shaft is operated usually with a code disk which the gray code pattern is printed on. Such encoder has inherently resolution limit because of the patterning mechanism and sensing mechanism. In order to measure the position of fringes which move as the code disk rotates, neural network was developed in this paper. Formerly fringe position is usually measured by a sophisticated software, which needs a little long calculation time. However, using neural network method can eliminate such calculation time, even though it needs learning job. The proposed method is verified through several experiments.

• 제어로봇시스템학회논문지
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• 제21권10호
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• pp.944-950
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• 2015

Recent studies on ankle-foot prostheses used for transtibial amputees have focused on the adaptation of the ankle angle of the prosthesis according to ground conditions. For adaptation to various ground conditions (e.g., incline, decline, and step conditions), ankle-foot prostheses should first recognize the ground conditions as well as the current human motion pattern. For this purpose, the ground reaction forces and orientation angle of the tibia provide fundamental information. The measurement of the orientation angle, however, creates a challenge in practice. Although various sensors, such as accelerometers and gyroscopes, can be utilized to measure the orientation angles of the prosthesis, none of these sensors can be solely used due to their intrinsic drawbacks. In this paper, a time-varying complementary filtering (TVCF) method is proposed to incorporate the measurements from an accelerometer and a gyroscope to obtain a precise orientation angle. The cut-off frequency of TVCF is adaptively determined according to the human gait phase detected by a fuzzy logic algorithm. The performance of the proposed method is verified through experiments.

• The Journal of Korean Physical Therapy
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• 제30권1호
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• pp.23-28
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• 2018

Purpose: This study examined the effectiveness of iliopsoas self-stretching on the hip extension angle, gluteus maximus (GM) activity, and pelvic compensated angle during prone hip extension (PHE) in subjects with iliopsoas shortness. Methods: Twenty-healthy subjects with iliopsoas shortness were recruited. Electromyography (EMG) was used to examine erector spinae (ES), multifidus (MF), GM, and biceps femoris (BF) while performing PHE. An electromagnetic tracking motion analysis device was used to measure the pelvic compensations. The pelvic compensations while performing PHE were considered to be anterior tilting and rotation. A modified Thomas test was used to monitor the hip extension angle before and after iliopsoas self-stretching. A paired t-test was used to investigate the significant difference after iliopsoas self-stretching during PHE. The level of statistical significance was set to ${\alpha}=0.05$. Results: Muscle activity of GM and hip extension angle were significantly greater after iliopsoas self-stretching compared to that before iliopsoas self-stretching during PHE (p<0.05). BF and pelvic rotation angle were significantly lower after iliopsoas self-stretching compared to that before iliopsoas self-stretching during PHE (p<0.05). The muscle activity of ES was not significantly different between PHE before and after iliopsoas self-stretching (p>0.05). Conclusion: Iliopsoas self-stretching can be effective in selectively strengthening the GM muscles with minimized pelvic compensation in subjects with iliopsoas shortness.

• 한국전문물리치료학회지
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• 제26권1호
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• pp.75-83
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• 2019

Background: A tight iliotibial band (ITB) may lead to lateral patellar maltracking, compression, and tilt, and dominant vatus lateralis (VL) muscle activation relative to vastus medialis oblique (VMO) can laterally displace the patella, which leads to anterior knee pain. Therefore, an effective management technique is needed to stabilize the patella in individuals with tight ITB. Increased stability during the modified Thomas test has the potential to decrease compensatory motion and thus to selectively stretch the ITB. Objects: The purpose of this study was to determine the effects of ITB stretching in the modified Thomas test position on ITB flexibility, patellar translation, and muscle activities of the VMO and VL during quadreceps-setting (QS) exercise in individuals with tight ITB. Methods: Twenty-one subjects with tight ITB were recruited. Digital inclinometer was used to measure the hip adduction angle during the modified Ober test. Universal goniometer was used to measure the hip abduction angle during the modified Thomas test. Ultrasonography was used to measure the patella-condylar distance. Electromyography was performed to collect data of muscle activities. Paired t-test was used to determine the statistical significance between pretest and posttest. Results: The range of hip adduction in modified Ober test increased (p=.04) and the range of hip abduction in the modified Thomas test decreased after ITB stretching (p<.01). There was no difference between lateral patellar translation (p=.18). VMO muscle activity significantly increased after ITB stretching during QS (p<.01). VL muscle activity had no difference after stretching. Conclusion: The ITB stretching in the modified Thomas test position can be suggested as a management method for improving ITB flexibility and VMO muscle activity in individuals with tight ITB.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.139-144
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• 2005

Because of the photorefractive recording dynamics, each newly recorded hologram partially erases all previously stored image. Thus achieving the desired diffraction efficiency profile for the entire sequence after all images have been recorded requires exposure time schedule. The often cited classical exposure-schedule model predicts a rising-exponential build-up and an exponential decay in An with an exposure time. However because we cannot directly measure the An, it's difficult to establish the relation of both. In this paper, we deduce the relation of diffraction efficiency and exposure time from experiment data and suggest an algorithm to make time schedule profile in angle/fractal multiplexing of holographic data storage. After that, we present simulated result with equal hologram diffraction efficiency for a sequence of 250 holograms recorded by angle/fractal multiplexing.

• 대한수의학회지
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• 제64권2호
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• pp.14.1-14.6
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• 2024

In human, ultrasonography is used to measure the pennation angle in various muscles to identify muscle functions such as force production, and to study alterations of the pennation angle during muscle contraction, hypertrophy, and atrophy. However, assessments of the pennation angle have not yet been conducted in dogs. This study aims to assess the normal pennation angle of the tibialis cranialis muscle in dogs using ultrasound and to detect changes in this angle in dogs with muscular atrophy. Sixty-eight healthy dogs were examined to establish normal values, while 12 ataxic and 12 lame dogs with suspected hindlimb muscle atrophy were also included. The pennation angle was measured using ultrasound at the midpoint between the proximal end of the tibia and the malleolus, measuring the angle between the muscle bundle and the deep aponeurosis. To confirm the significance between the 5 breeds and to identify a difference between normal and atrophied muscles, statistical analysis was conducted. The study found no significant difference in pennation angle between breeds, with mean values (± standard deviation) of 4.97° (± 1.88) in neutral, 7.25° (± 2.68) in flexion, and 3.31° (± 1.33) in extension positions. Decrease of the pennation angle was identified in muscle atrophy and the flexion position was determined to be the most appropriate for pennation angle measurement of tibialis cranialis muscle. We recommend considering the pennation angle as a valuable indicator of muscle health in dogs, as it demonstrates significant potential for diagnosing and monitoring muscular conditions.

• 대한의용생체공학회:의공학회지
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• 제31권1호
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• pp.67-73
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• 2010

The foot performs an important function in supporting the body and keeping body balance. An abnormal walking habit breaks the balance of the human body as well as the normal function of the foot. The influence of a flatfoot(pes planus) occupies a considerable portion of the various causes resulting in the wrong walking habit. But, little studies has been done by the functional foot orthotics for the flat foot. The object of this study, therefore, is to propose a new approach method to reveal the effects of the improvement of the foot function by using orthotics. The essential point of this study is to measure and analyze the change of ankle angle in the sagittal plane for flat foot subjects wearing the orthotics. Before and after wearing the functional orthotics, the gait analysis of flat foot subjects was conducted in three experimental aspects : the change of ankle angle, the change of the total Ankle ROM and the difference of left & right ankle angle in the sagittal plane. 1. The average ankle angle differences of before-and-after wearing the orthotics have declined like this; left : $2.71^{\circ}$, right: $1.91^{\circ}$ (p<0.05). 2. Total ankle ROM also showed decrease in both sides while the left side's is rather slight; left : $0.57^{\circ}$, right : $2.07^{\circ}$ (p<0.05). 3. The difference of left and right ankle angle in the sagittal plane decreased by $0.71^{\circ}$ (p<0.05). In result, it is confirmed that the functional foot orthotics have a significant effect on mechanical movement of ankle joint for flat foot. it is expected that this paper will be further studied and improved as a practical estimation method in the research on the effect of foot-orthotics.

• 대한수학교육학회지:학교수학
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• 제17권3호
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• pp.447-467
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• 2015

본 연구의 목적은 도(degree)와 라디안을 호의 측도로 해석하는 것이 라디안과 각의 측정에 대한 개념적 이해에 어떠한 영향을 미치는지 살펴보는 것이다. 이에 호의 길이를 이용한 각의 측도에 대한 내용지식을 26명의 예비중등교사를 대상으로 조사하였으며, 그 결과를 반영하여 두 명의 중학생들을 대상으로 실험을 진행하였다. 예비교사들과 두 중학생의 반응을 분석한 결과, 도(degree)의 개념을 호의 측도로 해석한 경험이 라디안의 이해에 긍정적인 영향을 미쳤으며, 호의 측도로 각의 측도를 파악하는 과정이 '선형 측정'에 대한 개념적 이해를 가능하게 하였다. 또한 각에 관한 다양한 문제에서 원의 맥락과 호의 등분 전략이 효과적인 문제해결전략으로 작용하였으며, 각과 호의 측도 사이의 관계를 탐구할 수 있는 직접적인 조작활동을 제공하는 것이 각의 측정 개념에 대한 이해에 도움을 줄 수 있다는 것을 확인하였다.

• 한국광학회지
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• 제12권3호
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• pp.235-239
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• 2001

본논문에서는 반강유전성 액정의 in-plane tilt 각이 약 $22.5^{\circ}C$인 특성을 가진다는 것을 이용하여 액정의 위상지연을 $\lambda/2$로 설계한 광대역 $\lambda/4$필름을 사용한 단일 편광판 모드 반사형 LCD의 구조를 제안하였으며 이구조의 여러 가지 광특석을 전사모사 해보았다. 실제 실험에서는 in-plane tilt 각이 $\24.9\lambda$인 Chisso상의 CS-4001 반강유전성 액정을 사용하여 액정 셀의 위상지연을 $\lambda/2$로 설계하여 각도에 따른 반사특성과 파장에 따른 분광특성을 측정하였다.