• 한국운동역학회지
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• 제23권2호
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• pp.91-97
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• 2013

The purpose of this study was to compare the effect of a new warm-up condition, overloaded arm weights (721 g each arm, [OA]), on the bat speed during warm-up and immediately after warm-up with traditional warm-up conditions such as no-extra mass warm-up (control condition, [CO]) and overloaded bat warm-up (885 g donut on a bat, [OB]) conditions. Twenty male subjects who had competitive baseball experience participated in this study. Electromagnetic motion capture system was used to capture body segment motions. Results indicated that the OB showed significantly slower bat speed than the CO and OA did during warm-up (p<.05) and the bat speeds of OA and OB were similar. There was no main effect of different types of warm-up condition on the bat speed at post-warm-up swings. However, the first trial immediately after the OA and OB showed significant slower than the later trials (p<.05). Conclusively, the overloaded arm weights and overloaded bat did not show statistical superiority than the standard warm-up conditions in the deck circle and recovery time more than 3 minutes after loaded warm-up is recommended.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.76-77
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• 2022

본 논문에서는 다시점에서의 자세 추정 결과를 정합하여 3D 볼류메트릭 데이터 시퀀스의 3D 자세 추정 결과의 떨림을 줄이는 방법을 제안한다. 볼류메트릭 모델을 중심으로 원을 그리며 일정 각도 간격의 시점에서 본 모델을 평면에 투사한다. 투영하여 얻은 2D 영상에 대해 Openpose를 이용하여 2D 자세 추정을 진행한 뒤, 2D 관절 정보를 정합하여 3D 관절 위치를 국한한다. 각도 간격에 따라 다른 3D 관절의 떨림의 정도를 수치화하여 표로 나타내고, 안정적인 결과를 위한 최소 조건을 확인하였다.

• 한국운동역학회지
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• 제18권4호
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• pp.1-19
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• 2008

본 연구의 목적은 스노우보더가 플랫폼에서 뛰어내릴 때 경사면에 착지 하는 지면반력 계산을 바탕으로 3가지 종류의 곡선(타원, 원, 브라키스토크론)으로 된 하프파이프의 곡면에 착지할 때의 충격에 대한 역학적 계산의 결과를 해석 하는 것이다. 스노우보더의 착지시 다리의 유연성, 눈이 다져진 정도 경사면의 각도, 초기 속도, 착지 후 동작의 숙련도 등이 충격을 줄여주는 중요한 요소로 작용한다. 그러나 딱딱한 스노우보드용 하프파이프에서는 착지 지점의 곡면에 절대적으로 좌우된다. 이 연구의 역학적 분석 결과 브라키스토크론 곡선이 좀 더 충격 흡수의 효과가 있어 안전한 것으로 판명되었다. 건설의 효율성만을 고려한다면 현재 통용되고 있는 타원형태 이외의 다른 종류의 곡선들은 필요 없다고 생각하기 쉬우나 스노우보더들이 구사하는 기술의 종류와 난이도에 따라서 다양한 기하학적 형태의 시설로 발전되는 것이 바람직하다. 본 연구에서 시행된 연구 방법은 스노우보더 들의 치명적 부강 방지를 위한 하프파이프의 최적 안전 설계 및 사용의 방법과 더불어 스포츠인 들의 사고를 줄일 수 있는 과학적 연구방법에 대한 하나의 모델을 제시 한 것이라고 볼 수 있다.

• 수산해양기술연구
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• 제28권1호
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• pp.21-26
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• 1992

Generally a navigator evaluated the maneuverability of his ship by the scale of turning circle which was described only by the largest rudder angle of the port and starboard sides. But to have the sufficient knowledge of his ship's maneuvering characteristics he should consider the data about the new course keeping test, the spiral test, and the turning circle tests in accordance with the rudder angles together. In this paper the author performed the above tests to study the maneuverability of the stern trawler M.S. Pusan 404 which is a training ship of the National Fisheries University of Pusan. The obtained results are summarized as follows: 1. When the rudder angles being 5。, 10。, 20。, 30。, 35。 the advances of the starboard side turning circles were 12.8, 8.2, 4.8, 2.9, 2.7 times as large as the length of the ship, and of the port side turning circles were 13.3, 8.7, 5.4, 3.5, 2.9, time as large as the large as it. Under the same conditions the tactical diameters were 15.1, 9.7, 5.2, 3.1, 2.8 times as large as the length of the ship, for starboard side, and 17.2, 12.4, 6.4, 3.7, 3.2 times as large as it for port side. 2. As the rudder angle being increased the ratio of the advance to the tactical diameter was nearly 1 and her obeying ability was better than that of the small angle. 3. The mean values of the rates of speed reduction during the steady turning motion were 0.96, 0.92, 0.82, 0.71, 0.65 in accordance with the rudder angles. 4. The relative formulas between the distance to the new course y and the altering course x were as follows: When rudder angles being 10。, 20。, 30。, y=52.2222+1.6133x, y=48.750+0.9383x, y=39.250+0.655x respectively. 5. There was little difference of the distance to the new course between rudder angle 20。and 30。, and so it is desirable for a navigator to a navigator to use the small rudder angles unless sudden emergencies. 6. Though her rudder angle being small her course stability was good according to the spiral tests.

• 천문학논총
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• 제28권2호
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• pp.25-36
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• 2013

Chumsungdae is an ancient astronomical observatory whose main role was doing 'chunmoon'. It was administrate by a royal advisory agency on state affairs. The observers observed the heaven on the observatory platform, recorded peculiar events, and watched and interpreted the signs displayed in the heaven. Chumsungdae is an stonemasonry which represents almanac principles with its peculiar shapes and the numbers of strata and stones. The numbers were thoroughly invented to match exactly the almanac constants. Chumsungdae is comprised largely of three main parts, namely the square base, the stratified cylindrical body, and the top #-shaped stonework, and the total number of stones is 404. The number of the strata (27) and the height of the cylindrical body (27 尺) stand for the days in a sidereal month (27.3 days), which implies that the motion of the Moon with respect to the stars was given more priority than to the Sun at that time of geocentricism. And the cylindrical body was thoroughly designed to consist of 365 stones, which is of course the number of days in a solar year. In addition, there are 12 strata each under and above the south entrance and this in sum makes the 24 divisions of the year. Also there is 182 stones below the 13th stratum and this represents the number of days in the winter ~ summer solstice period, and the rest 183 stones the vice versa. The #-shaped top stonework was aligned in such a way that one of the diagonals points the direction of sunrise on the winter solstice. The square base also layed with the same manner. The south entrance was built 16 degrees SE, and the upright direction of the right pillar stone coincides with the meridian circle. This was a kind of built-in standard meridian circle facilitating the observations. In a symbolic sense, Chumsungdae was thought as the tunnel reaching the heaven, where the observers wished to be enlightened with the signs and inspirations in need. With the craftsmanship and skill, the builder reinforced the stratified cylindrical body with two sets of #-shaped beam stones, piercing at a right angle at 19th ~ 20th and 25th ~ 26th strata. Likewise, by placing the double #-shaped stonework with 8 beam stones on the platform of the observatory, both the stability of the stonemasonry and a guard rail for the nightly observers were securely provided.

• 한국환경복원기술학회지
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• 제22권6호
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• pp.1-14
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• 2019

Carbon storage is one of the regulating ecosystem services provided by urban street trees. It is important that evaluating the economic value of ecosystem services accurately. The carbon storage of street trees was calculated by measuring the morphological parameter on the field. As the method is labor-intensive and time-consuming for the macro-scale research, remote sensing has been more widely used. The airborne Light Detection And Ranging (LiDAR) is used in obtaining the point clouds data of a densely planted area and extracting individual trees for the carbon storage estimation. However, the LiDAR has limitations such as high cost and complicated operations. In addition, trees change over time they need to be frequently. Therefore, Structure from Motion (SfM) photogrammetry with unmanned Aerial Vehicle (UAV) is a more suitable method for obtaining point clouds data. In this paper, a UAV loaded with a digital camera was employed to take oblique aerial images for generating point cloud of street trees. We extracted the diameter of breast height (DBH) from generated point cloud data to calculate the carbon storage. We compared DBH calculated from UAV data and measured data from the field in the selected area. The calculated DBH was used to estimate the carbon storage of street trees in the study area using a regression model. The results demonstrate the feasibility and effectiveness of applying UAV imagery and SfM technique to the carbon storage estimation of street trees. The technique can contribute to efficiently building inventories of the carbon storage of street trees in urban areas.

• 한국지능시스템학회논문지
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• 제25권1호
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• pp.78-84
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• 2015

로봇 비전, 3차원 형상 모델링 그리고 모션 제어를 하기 위해 3차원 깊이 추정이 필요하다. 기존에 제안 되었던 깊이 추정 방법은 렌즈와 물체사이의 거리를 변화시켜 가면서 취득된, 일련의 전체영상에 대해서 초점값을 계산하는 방법에 기초하고 있다. 그러나 이러한 방법은 전체 영상에 대해서 초점값 계산을 위한 마스크 연산을 하기에 수행 시간이 오래 걸리는 단점이 있다. 이에 반해서 본 논문에서 제안하는 방법은 물체간의 깊이를 추정하는 시간을 개선하기 위하여 전체 영상을 고려하지 않고, 물체간의 경계면과 경계면 부근의 영상 정보만을 이용하여 깊이를 추정한다. 특히 직선과 원으로 구성된 물체의 경계면을 검출하기 위해서 허프 변환을 이용하였으며, 깊이 추정은 초점 정보를 이용하였다. PCB 영상을 이용하여 실험을 수행한 결과, 이전에 비해서 더욱 효과적인 깊이 추정이 가능함을 알 수 있었다.

• 대한예방한의학회지
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• 제18권2호
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• pp.115-123
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• 2014

Objective : The objective of this study is to develop a Qigong exercise program to reinforce musculoskeletal system of seniors appropriate for physical strength and conditions of seniors aged 65 years or above based on health Qigong exercise of oriental medicine. Method : Qigong exercise motions that can improve strength, muscular endurance, flexibility, and cardiovascular endurance of seniors were developed by primarily performing literature review of Qigong experts on the fields like oriental medicine, Qigong exercise, physical education and health science and secondarily using motion training for increased validity of motions. Results : The Qigong exercise program for musculoskeletal system of seniors was designed with 12 motions repeated 8 times and 20 minutes per session, including shoulder exercises (alternate turning of left and right shoulders, turning both arms back and forth, holding and lifting elbow to put it aside), waist exercises (wrapping the head with hands to bow, twisting waist while looking at the tip of hand, large spinning of ball, putting hands together to pull back), and knee exercises (going up a down while lifting a rock, balancing the body while lifting a knee, lifting and spreading knees while drawing circle with arms, raising both arms to the side while lifting heels, breathing). Conclusion : Once the effects of Qigong exercise for musculoskeletal system of seniors developed in this study are tested, the program is expected to contribute to development of Qigong exercise, a core part of oriental medicine health improvement project.

• Archives of Plastic Surgery
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• 제33권6호
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• pp.715-722
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• 2006

Purpose: The main advantages of the perforator flap are minimal donor site morbidity, preservation of any main source artery and its thin characteristics. Most perforator flaps for hand reconstruction need primary and secondary procedures such as a flap debulkiness and liposuction etc. However, flap thickness of calf area is thinner than any other perforator flaps. Methods: We performed an anatomical study and clinical application of medial sural artery perforator flap. We found that there are two or more medial sural perforators located on a straight line drawn from the mid-point of popliteal crease to the mid-point of medial malleolus. Most pathway of medial sural artery comes along with this line. It is possible to observe the first perforators almost exactly 8 cm from midpoint of popliteal crease in a distal half circle drawn with a radius of 2 cm. Results: We report 12 cases in 11 patients of hand reconstruction with medial sural perforator free flap from Febrary 2003 to Febrary 2006. Complete healing was possible in 11 cases. Total flap loss for venous insufficiency was in 1 patient. During the follow-up, good contour and full range of motion was observed on hand reconstruction with medial sural perforator free flap. Conclusion: In the authors' experience, this anatomical study made it possible to prepare a diagram of the exact location of the medial sural perforators. This flap can be used to achieve acceptable functional and aesthetic results for hand reconstruction because of its thin characteristics.

• 전자공학회논문지 IE
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• 제46권3호
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• pp.33-41
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• 2009

본 논문에서는 Limit-cycle 항법의 안정성을 분석하고 path follwer를 제안한다. Limit-cycle 항법은 2차 비선형 함수의 특징을 이용하며, 빠른 이동로봇의 움직임을 제어하기 위해 제안되어졌다. Limit-cycle의 수렴반경과 방향을 조절하여 충돌 없이 장애물을 회피하고, 목표점에 도달할 수 있다. 하지만 지금까지 Limit-cycle 항법의 안정성은 연구되어지지 않았다. 따라서 본 논문에서는 이러한 안정성을 분석하고, Limit-cycle 항법을 로봇축구에 적용하여, 시뮬레이션과 실제 실험에서 제안된 방법을 검증한다.