• 한국산학기술학회논문지
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• 제18권7호
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• pp.734-740
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• 2017

낮은 프레임률을 가지는 동영상을 높은 프레임률 디스플레이 장치를 통해 재생하는 경우 프레임률 향상기법이 필요하다. 프레임 향상 기법은 연속된 원본 프레임 사이에 프레임을 보간함으로써 생성하며 이러한 프레임 보간방법은 크게 프레임 복사 기법과 움직임벡터 기반의 보간기법으로 나뉜다. 프레임 복사 기법은 단순히 보간하고자 하는 프레임의 이전 또는 이후 프레임을 복사하는 기법으로 매우 낮은 복잡도를 가지지만 저키현상이 발생하는 단점이 있다. 움직임 벡터 추정 및 보상을 통한 프레임 보간기법은 다시 화소단위의 방법과 블록단위의 움직임 추정 방법으로 나눌 수 있다. 화소기반의 경우 영역별 다른 보간 방법을 사용하여 보간을 수행하며 높은 복잡도를 가지는 단점이 있다. 블록기반 방법은 상대적으로 낮은 복잡도를 가지지만 블록킹현상이 발생한다는 단점을 가진다. 제안하는 방법은 블록단위의 움직임 추정 기반 프레임률 향상기법으로 프레임내 움직임의 선형성을 이용하여 움직임을 추정한다. 이 과정에서 보간하고자 하는 프레임 이전 두 프레임과 이후 한 프레임을 사용하여 움직임 추정 및 보상을 수행함으로써 프레임을 보간하다. 실험결과 제안한 알고리즘은 객관적 화질 측면에서 이전의 다른 방법과 비교하여 높은 성능을 보이고 특히 해상도가 높은 경우 더욱 우수한 성능을 가지는 것으로 나타났으며 주관적 화질 또한 상대적으로 우수한 것을 볼 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1327-1332
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• 2000

Ultrasonic motors have an advantage over conventional electro-magnetic motors because of its excellent characteristics, such as high torque, low speed output, compact size, excellent controllability and, above of all, quite operation. The principle of operation of ultrasonic motors is to generate gross mechanical motion through the amplification and repetition of micro-deformations of active materials. A brief description of working principle and methods of analysis of dynamic behaviors of ultrasonic motors are given for the extended research and development activities anticipated in the mechanical engineering community.

• 국제물리치료학회지
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• 제11권4호
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• pp.2229-2236
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• 2020

Background: Few comparative studies have been conducted on strengthening the anterior and posterior muscles of the trunk via lumbar stabilization exercises. Objectives: To compare the effects of forward leaning exercise and supine bridging exercise in stability exercise. Design: Randomized controlled clinical trial (single blind). Methods: Thirty subjects with spondylolisthesis were participated in this study. Fifteen subjects performed the bridging exercises and fifteen subjects performed the forward leaning exercises. Each exercise was held for ten seconds per repetition, and four repetitions were considered one sub-session. A total of four sub-sessions were performed in one full exercise session. The full exercise session required thirty minutes, including rest time. Trunk strength and range of motion and Oswestry disability index were measured. Results: Two weeks later, trunk flexion strength and trunk extension range of motion were significantly increased in the forward leaning exercise group than in the supine bridging group, trunk extension strength were significantly increased in the supine bridging exercise group than in the forward leaning group. After two weeks, the pain score was significantly lower in the forward leaning exercise group than in the supine bridging group. Conclusion: This study has shown that stabilization exercises are effective in increasing range of motion and strength in spondylolisthesis subjects. It was especially confirmed that the method of strengthening the anterior muscles of the trunk is more effective than the standard stabilization exercise method.

• 한국멀티미디어학회논문지
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• 제22권4호
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• pp.432-442
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• 2019

Most current human action recognition methods based on deep learning methods. It is required, however, a very high computational cost. In this paper, we propose an action change detection method to reduce repetitive human action recognition tasks. In reality, simple actions are often repeated and it is time consuming process to apply high cost action recognition methods on repeated actions. The proposed method decides whether action has changed. The action recognition is executed only when it has detected action change. The action change detection process is as follows. First, extract the number of non-zero pixel from motion history image and generate one-dimensional time-series data. Second, detecting action change by comparison of difference between current time trend and local extremum of time-series data and threshold. Experiments on the proposed method achieved 89% balanced accuracy on action change data and 61% reduced action recognition repetition.

• 한국콘텐츠학회논문지
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• 제19권4호
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• pp.458-465
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• 2019

실험애니메이션은 실험정신 그 자체로 독립 예술애니메이션이자 작가주의적 실험정신으로 집약된 영상예술이다. 특히 노먼 맥라렌은 뛰어난 창의력과 감성으로 시각적 표현 기술에 대한 과학적 탐구와 상식을 초월한 실험을 통해 작품마다 독창적인 조형미를 추구하며 오늘날 영상매체의 혁신을 불러온 실험애니메이션의 거장으로써 애니메이션 작품의 미학적 가치는 매우 높다. 그러므로 다양한 기법의 도전으로 실험애니메이션의 영역을 확장하고 각 프레임 사이에서 일어나는 움직임 창조에 관한 끊임없는 탐구를 수행했던 노먼 맥라렌의 실험적 표현 방식을 분석하고 그가 집중한 움직임의 표현을 연구하는 것은 의미가 있다. 그 결과 그의 움직임 표현의 가장 큰 특징은 운동성의 반복과 변형의 반복으로 분석되었으며 이러한 도출이 실험 방식에 대한 단순 의문보다는 보다 구체적인 형태의 탐구가 요구되는 실험 방식의 실험애니메이션으로 이해되길 바란다. 또한 대학교육에서 애니메이션 창작의 가능성과 나아갈 방향을 심층적으로 모색하기 위한 선행 연구로 의미가 있기를 바란다.

• 전기학회논문지
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• 제58권11호
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• pp.2275-2280
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• 2009

u-Healthcare service is one of attractive applications in ubiquitous environment. In this paper, we propose a method to recognize exercises using a new accelerometer based body-attached platform for supporting u-Healthcare service. The platform consists of a device for measuring accelerometer data and a device for receiving the data. The former measures a user's motion data using a 3-axis accelerometer. The latter transmits the accelerometer data to a computer for recognizing the user's exercise. The algorithm for exercise recognition classifies the type of exercise using principle components analysis(PCA) from the accelerometer data transformed by discrete fourier transform(DFT), and estimates the repetition count of the recognized exercise using a peak detection algorithm. We evaluate the performance of the algorithm from the accuracy of the recognition of exercise type and the error rate of the estimation of repetition count. In our experimental result, the algorithm shows the accuracy about 98%.

• 한국전문물리치료학회지
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• 제30권4호
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• pp.275-280
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• 2023

Background: Although warm-ups before exercise are widely accepted, research on sex differences in improving hamstring flexibility is limited. Differences in the physical and physiological characteristics between males and females may result in different responses to warm-ups. Objects: This study aimed to examine sex differences in the effects of specific warm-up on hamstring flexibility. Methods: This study included 24 young adults with hamstring tightness. The participants performed five maximal knee extensions and flexions at 90° flexion of the hip, and the maximal knee extension angle was measured in real-time using a smartphone clinometer application. Results: The groups did not significantly affect the maximal knee extension angle but showed a significant effect for repetition (p = 0.002) and group-repetition interaction (p = 0.002). Males had no significant change in hamstring flexibility; however, females showed a significant increase in flexibility in the 5^th trial compared with the 1^st trial (p = 0.041). These results demonstrated sex-specific differences in flexibility improvement over time. Conclusion: The findings of this study suggest that specific warm-up can successfully improve hamstring flexibility in females. This may be due to various factors, such as muscle stiffness of the lower extremity, estrogen levels, and temperature sensitivity. In clinical settings, specific warm-up might be helpful for females who participate in sports or activities, such as running or jumping, which require a full range of motion in the hip and knee joints.

• 한국멀티미디어학회논문지
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• 제24권8호
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• pp.1035-1043
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• 2021

The shoulder is less stable than other joints, making it easier to onset of various shoulder disorders. In addition, limited range of motion and pain in the shoulder due to shoulder disorders restricts daily life and social activities. The problem with exercise therapy can be reduced in exercise effect by causing boredom through simple repetition of motion, thus reducing the patient's willingness to participate. Therefore, this paper aims to provide a treatment method that can induce active participation of patients by developing devices capable of passive, active, and resistance exercise and serious game contents using them. Furthermore, sEMG was used to verify whether the rotational exercise in the horizontal and vertical using serious game contents helps the shoulder movement actually. The measured sEMG signal was classified as 5 phases according to the angle of rotation and calculated the mean integrated EMG. The mean integrated EMG for the experimental results was higher in all phases when rotational was performed compared to those when both horizontal and vertical rotational exercise remained initial posture, indicating an increase in muscle activity.

• The Journal of Korean Physical Therapy
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• 제23권4호
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• pp.45-51
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• 2011

Purpose: To determine the correct measurement methods of the ankle joint complex range of motion for measuring the neutral position and evaluate the rater reliability. In addition, the impact of training on the rater reliability was also assessed. Methods: The subjects were eleven healthy women, who were evaluated by two physical therapists and one physical therapist recorded the results of the study. Standard goniometer was used as the measurement tool. The ankle and subtalar joint neutral position and the active range of motion of the ankle and subtalar joint were measured. Intra-rater reliability and inter-rater reliability measures were analyzed with intraclass correlation coefficients. Results: Intra-rater reliability and inter-rater reliability ranged from high to medium for the neutral position of the ankle joint complex. Intra-rater reliability for dorsiflexion and plantarflexion measurements was medium, while the inter-rater reliability was high. The range of motion of the subtalar joint was measured, and the intra-rater reliability and inter-rater reliability were low and medium, respectively Also, the intra-rater reliability was increased with formal training of the measurement techniques. Intra-rater reliability was reduced in case the raters had not undertaken the training. Conclusion: In summary, the results obtained with the measurement tools and joint measurement of position, indicate the consistency of repeated measurements made by the same observers. Under the same circumstances along with repetition of the same measurement technique during training caused an increase in the rater reliability of formally trained raters.

• 전자공학회논문지CI
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• 제39권2호
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• pp.35-44
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• 2002

카메라의 이동과 회전은 영상 프레임 전체에 영향을 미치는 전역 움직임(global motion)을 유발한다. 이러한 전역 움직임을 포함하는 영상을 부호화하는 경우, 변화성분 검출(change detection) 기법을 사용하여 정확한 오브젝트를 분할하는 것은 실제적으로는 불가능하며 큰 움직임 벡터로 인해 높은 압축률을 얻기 어렵다. 이러한 문제는 전역 움직임이 보상된 영상 시퀀스를 사용함으로써 해결할 수 있다. 전역 움직임 보상을 위한 기존의 카메라 움직임 추정 방법들은 계산량이 많다는 문제점을 가지고 있다. 따라서, 본 논문에서는 간단한 선 형식으로 구성되는 전역 움직임 추정 알고리즘을 제안한다 제안 알고리즘은 영상 프레임 내의 대칭점(symmetric points)의 움직임 정보를 이용하여 패닝(panning)과 틸팅(tilting), 줌잉(zooming)에 대한 전역 움직임 파라미터를 산출한다. 전역 움직임 계산에는 카메라 회전에 대해 깊이(depth)에 독립적인 원경만이 사용되며, 영상 내에서 원경을 구분하기 위한 판별식도 논문에 제시된다. 또한, MPEG 시험 영상을 사용한 실험 결과도 나타내었다. 본 논문에서 제안한 기법의 실시간 수행 능력은 많은 영상처리 분야의 전처리 단계에서 사용될 수 있다.