• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.285-292
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• 2016

For articulated swimming robots, there have been no researches about controlling the motion or trajectory following. A control method for articulated swimming robot is suggested by extending a previous algorithm, ESPG (Extended Swimming Pattern Generator). The control method focuses on the situation that continuous pre-determined swimming pattern is applied for long range travelling. In previous studies, there has not been a way to control the propulsive force when a swimming pattern created by ESPG was in progress. Hence, no control could be made unless the swimming pattern was completed even though an error occurred while the swimming pattern was in progress. In order to solve this problem, this study analyzes swimming patterns and suggests a method to control the propulsive force even while the swimming pattern was in progress. The angular velocity of each link is influenced and this eventually modifies the propulsive force. However, The angular velocity is changed, a number of problems can occur. In order to resolve this issue, phase compensation method and synchronization method were suggested. A simple controller was designed to confirm whether the suggested methods are able to control and a simulation has affirmed it. Moreover, it was applied to CALEB 10 (a biomimetic underwater articulated robot) and the result was verified.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.219-221
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• 2014

The objective of this paper is to simulate the dynamic behavior of a floating structure model, using image processing and close-range photogrammetry, instead of the contact sensors. Previously, the movement of structure was presented through the exterior orientation estimation of a single camera by space resection. The inverse resection yields the 6 orientation parameters of the floating structure, with respect to the camera coordinate system. The single camera solution is of interest in applications characterized by restriction in term of costs, unfavorable observation conditions, or synchronization demands when using multiple cameras. This article discusses the theoretical determinations of camera exterior orientation based on Direct Linear Transformation and photogrammetric resection using least squares adjustment. The proposed method was used to monitor the motion of a floating model. The results of six degrees of freedom (6-DOF) by inverse resection show that the appropriate initial values by DLT can be effectually applied in least squares adjustment, to obtain the precision of exterior orientation parameters. Additionally, a comparison between the close-range photogrammetry and total station results was feasibly verified. Therefore, the proposed method can be considered as an efficient solution to simulating the movement of floating structure.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.565-573
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• 2017

This paper presents a multistage in-flight alignment (MIFA) method for a strapdown inertial navigation system (SDINS) suitable for moving vehicles with no initial attitude references. A SDINS mounted on a moving vehicle frequently loses attitude information for many reasons, and it makes solving navigation equations impossible because the true motion is coupled with an undefined vehicle attitude. To determine the attitude in such a situation, MIFA consists of three stages: a coarse horizontal attitude, coarse heading, and fine attitude with adaptive Kalman navigation filter (AKNF) in order. In the coarse horizontal alignment, the pitch and roll are coarsely estimated from the second order damping loop with an input of acceleration differences between the SDINS and GPS. To enhance estimation accuracy, the acceleration is smoothed by a scalar filter to reflect the true dynamics of a vehicle, and the effects of the scalar filter gains are analyzed. Then the coarse heading is determined from the GPS tracking angle and yaw increment of the SDINS. The attitude from these two stages is fed back to the initial values of the AKNF. To reduce the estimated bias errors of inertial sensors, special emphasis is given to the timing synchronization effects for the measurement of AKNF. With various real flight tests using an UH60 helicopter, it is proved that MIFA provides a dramatic position error improvement compared to the conventional gyro compass alignment.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.139-160
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• 2003

The purpose of this study was to suggest the guideline for scientific and quantitative skill acquisition methods of badminton smashing so that the novice could learn the motions of badminton smashing efficiently. The subject participated consisted of total 6 middle school students of the stilled(3) and the unskilled(3). The cinematographical experimental & Analysis equipments used in the study were composed of two Model D-5100 Video Cameras, a control point, a synchronization timer and Kwon3d motion analysis system. The conclusions obtained were as follows, 1. It was necessary for the unskilled to learn the smashing impact phase in situation of max. velocity of COG in order to minimize the timing loss phase. 2. Particularly. The power from segments of Power Zone must participate in utilization in sequence of order of trunk-upper arm- forearm-hand-racket segment in both the skilled and the unskilled.. 3. Therefore it was necessary for the unskilled to do smashing practice for cumulated sum of absolute & relative velocity transfer into shuttle cock after adjusting anterior-posterior tilting angle and max timing, in sequence of segment recruited.

• Investigative Magnetic Resonance Imaging
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• v.25 no.4
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• pp.252-265
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• 2021

Cardiac magnetic resonance imaging (MRI) serves as a clinical gold-standard non-invasive imaging technique for the assessment of global and regional cardiac function. Conventional cardiac MRI is limited by the long acquisition time, the need for ECG gating and/or long breathhold, and insufficient spatiotemporal resolution. Real-time cardiac cine MRI refers to high spatiotemporal cardiac imaging using data acquired continuously without synchronization or binning, and therefore of potential interest in overcoming the limitations of conventional cardiac MRI. Novel acquisition and reconstruction techniques must be employed to facilitate real-time cardiac MRI. The goal of this study is to discuss methods that have been developed for real-time cardiac MRI. In particular, we classified existing techniques into two categories based on the use of non-iterative and iterative reconstruction. In addition, we present several research trends in this direction, including deep learning-based image reconstruction and other advanced real-time cardiac MRI strategies that reconstruct images acquired from real-time free-breathing techniques.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.107-116
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• 2011

Rigid soil containers (or rigid boxes) are often used for 1g shaking table tests. The rigid boxes, however, do not accurately simulate the amplification of ground acceleration and phase difference of seismic motion in the model ground due to the confinement of shear deformation and the reflection of seismic wave at the box walls. Laminar soil containers (or laminar shear boxes) can simulate the free field motion at convincingly superior accuracy than the rigid ones. In this study, the soft ground is modeled for both types of boxes and is subjected to seismic loading using a 1g shaking table. The comparison of the results using the two types of soil containers illustrates that, in case of the rigid box, the ground acceleration shows non uniform distribution and the phase synchronization of input motion. Whereas, the dynamic behavior of the laminar shear box shows good agreement with the free field behaviors such as the amplification of ground acceleration and the occurrence of phase difference.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8933-8939
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• 2015

In this paper, we designed a multi humanoid robot control method for performing an exhibition that will maximize the efficiency and user convenience and implementation. In recent years, an increasing number of case and to take advantage of the robots in the field performances and exhibitions, plays, musicals, orchestra performances are also various genres. In concert with the existing small humanoid exhibition to source from outside by using a computer and MP3 player and play, while pressing the start button of communication equipment for the show to start the robot began performing with the zoom. Thus, due to the dual source and robot operation and synchronization does not work well is the synchronization of the start of the concert sound starting point of the robot and robot motion and sound are reproduced separately were frequently occurs when you need to restart the show. In addition, when the center of gravity or lose the robots who were present during the performance problems such as performance or intervene to restart the show. In order to overcome this, in this paper, Multi-small humanoid robot was designed to control the efficiency and the user of the GUI-based human interface S/W to maximize convenience, Zigbee communication to transmit a plurality of data in al small humanoid It was used. In addition, targeting a number of the small humanoid robot demonstrated the effectiveness and validity of the user's convenience by gender actual implementation.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.4
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• pp.165-173
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• 2017

This study aims at validating simulations of the forced and freely vibrating cylinders at Reynolds number of approximately 500 in order to identify the capability of the CFD code, and to establish the analysis process of the vortex-induced vibration (VIV). The direct numerical and large eddy simulations were employed to resolve the various length scales of the vortices, and the morphing technique was used to consider a motion of the circular cylinder. For the forced vibration case, both in- and anti-phase VIV processes were observed regarding the frequency ratio. Namely, when the frequency ratio approaches to unity, the synchronization/lock-in process occurs, leading to substantial increases in drag and lift coefficients. This is strongly linked with the switch in timing of the vortex formation, and this physical tendency is consistent with that of Blackburn and Henderson (J. Fluid Mech., 1999, 385, 255-286) as well as force coefficients. For the free oscillation case, the mass and damping ratio of 50.8 and 0.0024 were considered based on the study of Blackburn et al. (J. Fluid Struct., 2000, 15, 481-488) to allow the direct comparison of simulation results. The simulation results for a peak amplitude of the cylinder and a shedding mode are reasonably comparable to that of Blackburn et al. (2000). Consequently, based on aforementioned results, it can be concluded that numerical methods were successfully validated and the calculation procedure was well established for VIV analysis with reasonable results.

• Cartoon and Animation Studies
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• s.24
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• pp.135-154
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• 2011

Simulacra theory as propounded by Jean Baudrillard in his seminal treatise, "Simulacra and Simulation," explores the significance of images, media and art in contemporary culture. Its central theoretical premise is the simulacrum, a sign or symbol that plays a crucial role in constructing perceived reality but which lacks a real-world referent. In Michel Gondry creates simulacra in the form of hallucinatory dream imagery by combining stop-motion animation and live-action elements. As experimental film-making that combines analog and minimum digital technologies, the result is a tour-de-force of synchronization. This study analyzes the film's technique and expressive content and, by adopting simulacra theory as a conceptual framework, aims to provide a better understanding of Gondry's work.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.38-40
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• 2005

Microdrive with high precision and light mass enough to install on mouse head was fabricated for recording the reliable signal of neuron cell to understand the brain study. The proposed microdrive has three H-form PZT actuators and its guide structure. The microdrive operation principle is based on the well known inchworm principle. The synchronization of three PZT actuators is able to produce the linear motion along the guide structure. Our proposed microdrive has a precise accuracy of about 100nm and a long stroke of about 5mm. The electrode which is used for the recording of the action potential of the neuron cell was fixed at one of PZT actuators. The proposed microdrive was suited to acquisition of signals from in vivo extra-cellular single-unit recoding. On the condition of the anesthetized mouse, the single-unit signals could be recorded by using the proposed microdrive. In addition, applying the PZT microdrive to an alert mouse, we try to implant it on a mouse brain skull to explore single neuron firing.