• 한국운동역학회지
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• 제17권2호
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• pp.83-91
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• 2007

This experiment studied the change in a human's control of his or her static posture by analyzing the stabilogram diffusion and, by using the said study, evaluated the control ability of different groups with different experiences. The postures had a rising requirement of heel-rise according to three conditions: heel-toe, ball, toe; the groups were divided into dance major student and non-dance majors. The results of the critical points according to posture did not show a direct relation with the change in postures that had a rising requirement of heel-rise. The diffusion coefficient(D) had greater stochastic activity for short-term regions that utilize open-loop controls without feedback than for long-term regions that used closed-loop controls with feedback to maintain balance. The directional results of the body undergoing disturbance showed that A/P direction's diffusion coefficient (D) was larger than that of M/L direction. Both feet's planar diffusion coefficients were a linear combination of the diffusion coefficients calculated for the x and y axis. In studying the different abilities to control posture between a dance major student and a non-dance majors, a comparison of open-loop control's diffusion coefficient(D) was effective, and dance major student had superior control ability to that of non-dance majors.

• The Journal of Korean Physical Therapy
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• 제14권4호
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• pp.487-497
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• 2002

The fatigue process of the triceps surae was evaluated during a standing heel-rise test, comparising of pre-fatigue and post-fatigue. Sixteen healthy subjects with a mean age of 22.88 years participated. The heel-rise test was performed until exhaustion, and electromyographic activity expressed as mean value and root mean square of the gastrocnemius and soleus muscles were calculated. The average number of heel-rise performed was 63.69$\pm$26.10. The result of this present study indicate that the EMG signal is sensitive to the different muscle fatigue. Mean value and RMS decreased significantly in after fatigue. Significant difference were found between the pre-fatigue and post-fatigue in the total subjects. But there were no significant changes in mean and RMS between the male and female during standing heel-rise test. The present results, showing decreased EMG signal in the triceps surae, could be used as reference when testing the fatigue process in different clinical conditions. Recommendations for standardization of a heel-rise test are given.

• 한국정밀공학회지
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• 제26권3호
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• pp.129-136
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• 2009

The estimation of muscle force is important to understand the roles of the muscles. The static optimization method can be used to figure out the individual muscle forces. However, muscle forces during the movement including muscle co-contraction cannot be considered by the static optimization. In this study, a hybrid static optimization method was introduced to find the well-matched muscle forces with EMG signals under muscle co-contraction conditions. To validate the developed algorithm, the 3D motion analysis and its corresponding inverse dynamics using the musculoskeletal modeling software (SIMM) were performed on heel-rise movements. Results showed that the developed algorithm could estimate the acceptable muscle forces during heel-rise movement. These results imply that a hybrid numerical approach is very useful to obtain the reasonable muscle forces under muscle co-contraction conditions.

• 한국전문물리치료학회지
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• 제28권2호
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• pp.132-137
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• 2021

Background: Flat feet can be identified by assessing the collapse of the medial longitudinal arch (MLA) and these conditions can trigger epidemiological changes in the feet. Many of previous studies compared the muscle activity of lower body in terms of intervention and dynamics to treat the structural defect of flat feet. However, few studies have investigated or analyzed the muscle activity of gastrocnemius muscle in the subjects with flat feet. Objects: This study investigated the differences in changes of medial and lateral plantar flexors in subjects with flat feet during bipedal heel-rise (BHR) task and analyzed the differences in muscle activity between two groups by measuring the electromyography (EMG) of abductor hallucis (AH), tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius (LG). Methods: A total of Twenty one adult females participated in this experiment. Subjects were assigned to groups according to the navicular drop test. The task was applied to the leg, where the heel lifting action prevailed. The muscle activity of the medial and lateral feet plantar flexors was evaluated, and the % maximum voluntary isometric contractions (%MVIC) of these were compared. Results: For the difference between groups the muscle activity (%MVIC) of LG muscle was statistically significantly low in flat feet group compared to healthy feet group (flat feet: 64.57, healthy feet: 90.17; p < 0.05). Conclusion: The results of this study will contribute to identifying the muscle activities of medial and lateral feet plantar flexors among subjects with flat feet, which can cause abnormal epidemiological changes in the feet.

• 대한물리치료과학회지
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• 제29권1호
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• pp.73-86
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• 2022

Background: The purpose of this study is to investigate the effect of plantar flexor on muscle fatigue and endurance when two different sport tapes are applied. Design: Cross-sectional design. Methods: Fifty-one healthy adults were randomly assigned to dynamic taping group (n=17), kinesio taping group (n=17), and control group (n=17). The dynamic taping group used the dynamic tape. The kinesio tape group used the kinesio tape, and the control group doesn't used tape. Every group performed heel rise test and sEMG for every during pre-test and post-test. To evaluate plantar flexor endurance, the number of times was measured during the heel rise test. Results: The number of heel rises increased significantly in the post-test in dynamic taping group compared to the pre-test, and In comparison between groups, the number of heel rises significantly increased in dynamic taping group compared to kinesio taping group and control group. PEF value was significantly increased in the post-test compared to the pre-test in dynamic taping group, and there was a significant difference between the three groups according to the taping application. Conclusion: The results of this study confirmed that dynamic taping was effective in musclular fatigue and endurance on plantar flexor in healthy adults. Based on these results, it is suggested that the application of dynamic tape can be suggested as one of the intervention methods for muscle endurance and muscle fatigue.

• 대한족부족관절학회지
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• 제14권2호
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• pp.109-114
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• 2010

Purpose: The purpose of this study was to report the surgical outcome of reconstruction of neglected chronic Achilles tendon ruptures with various methods including Achilles tendon allograft. Materials and Methods: Between October 2003 and November 2008, 8 consecutive neglected chronic Achilles tendon ruptures with the defect gap of more than 4 cm underwent surgical reconstruction including V-Y advancement, gastrocnemius fascial turn-down flap, flexor hallucis longus transfer and Achilles tendon allograft. There were 7 males and 1 female who were evaluated at more than 18 months after surgery. At the time of followup, all patients were assessed with regard to postoperative complications, their self-reported level of satisfaction, the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale, 10 repetitive single heel rise, single leg hopping test, and ankle range of motion. Results: The AOFAS score increased from average 71.4 (50-87) to 96.4 (86-100). All patients were able to perform 10-repetitive single heel raise and single leg hopping at the latest follow up. No patient experienced wound complications and deep infection. Six patients were rated as 'excellent' and the other two as 'good'. Conclusion: Neglected chronic Achilles tendon ruptures could be successfully treated with careful selection of the reconstruction method according to the amount of defect gap. With an extensive defect, Achilles tendon allograft can be a good option when the reconstruction is not feasible otherwise.

• 대한물리의학회지
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• 제12권3호
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• pp.67-71
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• 2017

PURPOSE: Muscle fatigue is a cause to change proprioception. The purpose of this study was to investigate the effects of calf muscle fatigue and visual control on postural balance during single-legged standing in healthy adults. METHODS: Nineteen healthy adults (male) were participated in this study (mean age: 24.36 years; mean height: 171.32 cm; mean weight: 64.58 kg). The postural balance (sway length, sway area, sway velocity of COG displacement) was measured by Balance Trainer System (BT4) in before and after calf muscle fatigue feeling in single legged stance. In this study, repetitive single-legged heel rise test was used to induce fatigue of the calf muscle. Paired t- test was used to compare the postural balance between before and after calf muscle fatigue. Data of subjects were analyzed using SPSS 22.0 (SPSS Inc., Chicago, IL, USA). Level of significance was set to .05. RESULTS: The sway length, sway area, sway velocity of COG (center of gravity) displacement after calf muscle fatigue feeling was significantly increased compared to before calf muscle fatigue feeling during single leg standing both eye open and close conditions (p<.05). CONCLUSION: This study suggested that calf muscle fatigue feeling has affected on postural balance when standing one leg both eye open and close conditions and postural control was disturbed by muscle fatigue and visual feedback in single leg standing.

• 한국수소및신에너지학회논문집
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• 제20권4호
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• pp.344-351
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• 2009

A multi-zone model was used to predict the operating range of homogeneous charge compression ignition (HCCI) engine, the boundaries of the operating range were determined by knock (presented by ring intensity), misfire (presented by sensitivity of indicated mean effective pressure to the initial temperature). A HCCI engine fueled with Di-Methyl Ether (DME) was simulated under different initial temperature and equivalence ratios, and the operating range was well produced by the model. Furthermore, the model was applied to develop the operating range for thermal stratification in the preceding condition of initial temperature and equivalence ratios. The computations were conducted using Senkin application of the CHEMKINII kinetics rate code.

• 대한의용생체공학회:의공학회지
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• 제30권3호
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• pp.241-246
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• 2009

Since inappropriate muscle forces mean that people cannot perform some activities related to roles of the muscle, muscle forces have been considered as an important parameter in clinic. Therefore, many methods have been introduced to estimate muscle forces indirectly. One of the methods is muscle tissue dynamics and it is widely used in commercial softwares including musculoskeletal model, such as SIMM. They, however, need motion data captured from 3-dimensional motion analysis system. In this study, we introduced an algorithm to estimate muscle forces in real-time by using joint angles. The heel-rise movements were performed for a normal with 3-dimensional motion analysis system, EMG measurement system, and electrogoniometers. Joint angles obtained from electrogoniometers and EMG signals were used to estimate muscle forces. Simulation was performed to find muscle forces using motion data which was imported into musculoskeletal software. As the results, muscle lengths and forces from the developed algorithm were similar to those from commercial software in pattern. Results of this study would be helpful to implement a tool to calculate reasonable muscle forces in real-time.

• 만화애니메이션 연구
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• 통권42호
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• pp.105-123
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• 2016

세계 만화시장은 디지털시장 중심으로 지속적인 발전을 꾀하고 있으며 한국만화 시장 역시 발 빠른 모습으로 세계 웹툰시장을 견인하고 있다. 급속한 성장세를 보이며 발전하고 있는 웹툰시장은 이제는 안정적 정착을 위한 기반이 마련되어야 할 때라고 생각한다. 국내 웹툰 시장은 국내 뿐만 아닌 글로벌 시장을 타깃으로 하고 있다. 국내 웹툰 업체들이 글로벌로 영역으로 활발히 확장화고 있는 가운데 출판만화시장 중심인 일본에서는 국내 디지털 시장으로의 진입을 시도하고 있다. 수출과 수입의 공존으로 국내시장은 출판만화와 웹툰으로 양질의 작품을 전 연령대가 공유할 수 있게 되었으며 글로벌 웹툰시장에서는 한국웹툰이 중심을 이루고 있다. 한국 웹툰의 초기모델을 보여준 라인웹툰은 영어, 중국어, 태국어, 인도네시아어로 번역되어 모바일 애플리케이션과 웹에서 모두 이용이 가능하도록 서비스 되고 있다. 하지만 라인웹툰의 선봉적인 역할에도 불구하고 한국웹툰의 수출은 시작점에 불과하다. 디지털 콘텐츠의 취약점인 불법유통과, 문화적 할인율을 최소한 한 작품의 소재 발굴, 완벽한 번역 현지화 서비스가 이루어진다면 세계 최고의 한국 웹툰은 국내 뿐 아닌 국제화 시장에서도 단연 1등의 자리를 지킬 것이라 생각된다. 또한, 롱런하는 국내 만화시장의 유통구조를 조성하기 위해서는 무엇보다 웹툰과 출판만화의 공존이 필수적이다. 종이책으로 제작 된 기존의 출판만화 형식에서 휴대성과 경제성의 장점을 지닌 디지털본으로 생산 확대하여 긴수명을 지닌 콘텐츠가 생성되어야 할 것이다. 기존의 인기 있는 수입, 국내출판물과 국내 웹툰이 차별화된 콘텐츠를 개발해 전세계가 모두가 즐길 수 있는 양질의 콘텐츠를 제공하고 국내에 소개 되지 않은 국외 콘텐츠까지 소개함으로써 만화시장의 장기적인 안정화를 이룰 것이다.