• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.244-255
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• 2019

Interest in renewable energy has been increasing in recent years for many reasons, and there have been many studies on new types of wave energy converters and mechanisms for them. However, in this paper, motion characteristics of a wave energy converter with a wave activating body type is studied with an experiment. In order to conduct the experiment, a simple wave activating body type's wave energy converter is proposed. Experimental variations consist of connection type and location. The connection type controls the rotation motions of structures, and the connection location controls the distance between structures. The movement of floating structures, such as rotation, velocity, and acceleration, is measured with a potentiometer and a motion capture camera. Using the recorded data, the motion characteristics derived from the experimental variations are investigated.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.308-313
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• 2012

Robust tuning rules of the motion profile are proposed to minimize the residual vibration. For asymmetric S-curve profile, tuning rules are analytically formulated using Laplace-domain approach. When the system modeling is known exactly, by placing a single zero of the motion profile on the pole of the system, the residual vibration can be perfectly eliminated under undamped system. However, if there are some amounts of the modeling errors, the residual vibration significantly increases. To track this issue, the robust tuning rules against modeling error are discussed. One of the proposed robust tuning rules is placing the multiple zeros of the motion profile on the pole of the system, and the other is placing the zeros of the motion profile around the pole of the system. Thanks to the proposed robust tuning rules, motion profile becomes more robust to modeling errors while minimizing the residual vibration. By simulation, the effectiveness of the proposed robust tuning rules is verified.

• Earthquakes and Structures
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• 제22권1호
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• pp.53-64
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• 2022

This study proposes an intelligent semi-active isolation system combining a variable-stiffness control device and ground motion characteristic prediction. To determine the optimal control parameter in real-time, a genetic algorithm (GA)-fuzzy control law was developed in this study. Data on various types of ground motions were collected, and the ground motion characteristics were quantified to derive a near-fault (NF) characteristic ratio by employing an on-site earthquake early warning system. On the basis of the peak ground acceleration (PGA) and the derived NF ratio, a fuzzy inference system (FIS) was developed. The control parameters were optimized using a GA. To support continuity under near-fault and far-field ground motions, the optimal control parameter was linked with the predicted PGA and NF ratio through the FIS. The GA-fuzzy law was then compared with other control laws to verify its effectiveness. The results revealed that the GA-fuzzy control law could reliably predict different ground motion characteristics for real-time control because of the high sensitivity of its control parameter to the ground motion characteristics. Even under near-fault and far-field ground motions, the GA-fuzzy control law outperformed the FPEEA control law in terms of controlling the isolation layer displacement and the superstructure acceleration.

• 대한전기학회논문지
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• 제38권9호
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• pp.740-752
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• 1989

Many works have been reported in various fields on the subject of controlling a robot with high-level robot languages. This paper presents one such effort and explains the development of an automatic robot programming system which utilizes the concept of the task level language. This system is expected to act as an intelligent supporting tool in robot programming and be put into practical use. Emphasis is placed on the role of the programming system as a tool that generates the executable robot program according to the user specified tasks. Several task level commands are used in the developed system, and the resulting inflexibility is complemented by the motion level commands of the motion level robot languages. Thus, the advantages of both task and motion level languages are utilized, and no knowledge of specific language grammer is needed even when using motion level commands. To increase the usability of the developed system, various methods are provided for supplementing the programming system using taught data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2370-2372
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• 1998

Recently we have developed an active stereo head-eye system with vergence, name it KIST HECter(Head-Eye System with Colored Stero Vision), based on the analysis of human's neck and eye motion at visual behavior. Our HECter is a five degree-of-freedom system composed of pan and tilt motion in neck part and independent vergence motion of binocular cameras and commonly shared elevation axis in eye part. And stereo vision Provides two color image, which are processed by powerful each TMS32080 vision board. The shape and size are designed to be almost same as human face. The ability to vergence has significant importance and gives many beneficial merits. On its mechanical implementation we adapt a non-parallelogram 4-bar linkage mechanism since it provides high accuracy in transfering motion and enables compact and flexible design.

• 한국운동역학회지
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• 제21권1호
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• pp.85-95
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• 2011

Three-dimensional(3D) motion analysis is a useful tool for analyzing sports performance. During the last few decades, advances in motion analysis equipment have enabled us to perform more and more complicated biomechanical analyses. Nevertheless, considering the complexity of biomechanical models and the amount of data recorded from the motion analysis system, subsequent processing of these data is required for event-specific motion analysis. The purpose of this study was to develop a basic golf swing analysis algorithm using a state-of-the-art VICON motion analysis system. The algorithm was developed to facilitate golf swing analysis, with special emphasis on 3D motion analysis and high-speed motion capture, which are not easily available from typical video camera systems. Furthermore, the developed algorithm generates golf swing-specific kinematic and kinetic variables that can easily be used by golfers and coaches who do not have advanced biomechanical knowledge. We provide a basic algorithm to convert massive and complicated VICON data to common golf swing-related variables. Future development is necessary for more practical and efficient golf swing analysis.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.999-1002
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• 2003

본 연구에서는 동작 검출 기법을 소형 화상 카메라에 적용하여 감시 영상을 실시간으로 검출하는 감시시스템을 구현하였다. 기존에 사용되던 차 영상의 화소 값을 이용한 동작 검출 기법은 배경 영상을 저장할 메모리가 필요하고 화소 단위의 데이터 처리로 인하여 수행 시간의 증가와 노이즈에 민감한 단점을 감수해야만 한다. 이러한 단점을 해결하고 노이즈에 강인한 성질을 갖게 하기 위해서 블록 단위로 특징값을 추출하여 비교하는 기법을 제안하였다. 블록별로 특징값을 얻는 경우 기준 영상의 블록 단위의 특징 값과 현재 영상의 블록 특징 값만을 비교하기 때문에 프레임 메모리가 필요없고 단지 기준 영상의 블록 특징 값만을 저장하면 된다. 또한 블록 단위로 특징 값을 구하는 과정에서 화소 값을 이용한 동작 검출 보다 노이즈에 대한 영향을 감소시키고 카메라의 흔들림 등에 덜 민감한 효과를 얻을 수 있었다.

• 한국정보통신학회논문지
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• 제8권1호
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• pp.74-79
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• 2004

본 연구에서는 동작 검출 기법을 소형 화상 카메라에 적용하여 감시 영상을 검출하는 감시시스템을 구현하였다. 기존에 사용되던 차 영상의 화소 값을 이용한 동작 검출 기법은 배경 영상을 저장할 메모리가 필요하고 화소 단위의 데이터 처리로 인하여 수행 시간의 증가와 노이즈에 민감한 단점을 감수해야만 한다. 이러한 단점을 해결하고 노이즈에 강인한 성질을 갖게 하기 위해서 블록 단위로 모션 정보를 추출하여 비교하는 기법을 제안하였다. 블록별로 모션 정보를 얻는 경우 기준 영상의 블럭 단위의 특징 값과 현재 영상의 블럭 특징 값만을 비교하기 때문에 프레임 메모리가 필요 없고 단지 기준 영상의 블럭 특징 값만을 저장하면 된다. 또한 블럭 단위로 특징 값을 구하는 과정에서 화소 값을 이용한 동작 검출 보다 노이즈에 대한 영향을 감소시키고 카메라의 흔들림 등에 덜 민감한 효과를 얻을 수 있다.

• 산업융합연구
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• 제20권4호
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• pp.15-21
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• 2022

코로나19의 확산과 함께 야외 운동이 제한되면서 실내에서 체감형 게임을 이용하는 이용자 수가 늘고 있다. 게이머를 대신하는 아바타 형식의 캐릭터 디자인 커스터마이징 시스템은 게이머에게 게임에 대한 매력을 높일 수 있다는 측면에서 개발자들에게 중요한 연구주제의 하나이다. 본 논문은 판매량이 많고 캐릭터 커스터마이징이 가능한 체감형 게임을 게임 분석 사례로 선택하였다. 선택된 세 개 게임의 캐릭터 커스터마이징 시스템 분석을 통해 커스터마이징 시스템의 중요한 요소를 추출하였다. 마지막으로 체감형 게임 캐릭터 커스터마이징 시스템의 단점을 도출하고 선택 시스템,변형 시스템,부분 시스템에 대해 개선안을 제시하였다. 이러한 제안이 향후 체감형 게임 캐릭터 커스터마이징 시스템 설계에 나름의 참고가 되기를 기대한다.

• 한국전문물리치료학회지
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• 제20권2호
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• pp.60-68
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• 2013

The purpose of this study was to assess the intra-rater test-retest reliability of tibial external rotation angle measurement using a smartphone-based photographic goniometer, DrGoniometer (DrG) compared to a three-dimensional motion analysis system (Vicon). The current study showed an interchangeable method using DrG to measure the tibial external rotation angle in standing knee flexion at $90^{\circ}$. Twelve healthy subjects participated in this study. A rest session was conducted 30 minutes later for within-day reliability and five days later for between-day intra-rater test-retest reliability. To assess the validity of the measurement using DrG, we used a three dimensional motion analysis system as a gold standard to measure the angle of tibial external rotation. Intra-class correlation coefficient (ICC) and the standard error of measurement (SEM) values were used to determine the within- and between- day intra-rater test-retest reliability of using DrG and a three dimensional motion analysis system. To assess validity, Pearson correlation coefficients were used for two measurement techniques. The measurement for tibial external rotation had high intra-rater test-retest reliability of within-day (ICC=.88) and between-day (ICC=.83) reliability using DrG and of within-day (ICC=.93) and between-day (ICC=.77) reliability using a three-dimentional motion analysis system. Tibial external rotation angle measurement using DrG was highly correlated with those of the three-dimensional motion analysis system (r=.86). These results represented that the tibial external rotation angle measurement using DrG showed acceptable reliability and validity compared with the use of three-dimensional motion analysis system.