• Journal of Ocean Engineering and Technology
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• v.33 no.2
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• pp.131-138
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• 2019

This study focused on the roll motion characteristics of a two-dimensional (2D) rectangular floating structure under regular beam sea conditions. An experiment was conducted in a 2D wave tank for a roll free decay test in calm water and the roll motion in a range of regular waves with and without heave motion to investigate the motion response and heave influence on the roll motion. A numerical study was carried out using Reynolds-averaged Navier Stokes (RANS)-based CFD simulations. A grid convergence test was conducted to accurately capture the wave condition on the free surface based on the overset mesh and wave forcing method. It was found in the roll free decay test that the numerical results agreed well with the experimental results for the natural roll period and roll damping coefficient. It was also observed that the heave motion had an impact on the roll motion, and the responses of the heave and roll motion from the CFD simulations were in reasonable agreement with those from the experiment.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.15-24
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• 1996

To generate workspace analytically using the robot kinematics, data on range of human joints motion, especially range of two degrees of freedom motion, are needed. However, these data have not been investigated up to now. Therefore, in this research, we are to investigate an interaction effect of motions with two degrees of freedom occurred simultaneously at the shoulder, virtual hip(L5/S1) and hip joints, respectively, for 47 young male students. When motion with two degrees of freedom occurred at a joint such as shoulder, virtual hip and hip joints, it was found from the results of ANOVA that the action of a degree of freedom motion may either decrease or increase the effective functioning of the other degree of freedom motion. In other words, the shoulder flexion was decreased as the shoulder was adducted or abducted to $60^{\circ}C$TEX>or abducted from $60^{\circ}C$TEX>to maximum degree of abduction, while the shoulder flexion increased as the joint was abducted from $60^{\circ}C$TEX> to $60^{\circ}C$TEX> The flexion was decreased as the virtual hip was bent laterally at the virtual hip joint, and also did as the hip was adducted or abducted from the neutral position. It is expected that workspace can be generated more precisely based the data on the range of two degrees of joint motion measured in this study.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.9
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• pp.771-778
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• 2004

Recently, various applications of robot system become more popular in accordance with rapid development of computer hardware/software, artificial intelligence, and automatic control technology. Formerly robots mainly have been used in industrial field, however, nowadays it is said that the robot will do an important role in the home service application. To make the robot more useful, we require further researches on implementation of natural communication method between the human and the robot system, and autonomous behavior generation. The gesture recognition technique is one of the most convenient methods for natural human-robot interaction, so it is to be solved for implementation of intelligent robot system. In this paper, we describe the state-of-the-art of advanced gesture recognition technologies for intelligent robots according to three methods; sensor based method, feature based method, appearance based method, and 3D model based method. And we also discuss some problems and real applications in the research field.

• Structural Engineering and Mechanics
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• v.66 no.5
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• pp.637-648
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• 2018

When the centers of mass and stiffness of a building do not coincide, the structure experiences torsional responses. Such systems can consist of the underlying soil and the super-structure. The underlying soil may modify the earthquake input motion and change structural responses. Specific effects of the input motion shall also not be ignored. In this study, seismic demands of asymmetric buildings considering soil-structure interaction (SSI) under near-fault ground motions are evaluated. The building is modeled as an idealized single-story structure. The soil beneath the building is modeled by non-linear finite elements in the two states of loose and dense sands both compared with the fixed-base state. The infinite boundary conditions are modelled using viscous boundary elements. The effects of traditional and yield displacement-based (YDB) approaches of strength and stiffness distributions are considered on seismic demands. In the YDB approach, the stiffness considered in seismic design depends on the strength. The results show that the decrease in the base shear considering soft soil induced SSI when the YDB approach is assumed results only in the center of rigidity to control torsional responses. However, for fixed-base structures and those on dense soils both centers of strength and rigidity are controlling.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.19-29
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• 2022

Natural user interface (NUI) is used for the natural motion interface without using a specific device or tool like a mouse, keyboards, and pens. Recently, as non-contact sensor-based interaction technologies for recognizing human motion, gestures, voice, and gaze have been actively studied, an environment has been prepared that can provide more diverse contents based on various interaction methods compared to existing methods. However, as the number of sensors device is rapidly increasing, the system using a lot of sensors can suffer from a lack of computational resources. To address this problem, we proposed a real-time multi-device control system for natural interactive platform. In the proposed system, we classified two types of devices as the HC devices such as high-end commercial sensor and the LC devices such astraditional monitoring sensor with low-cost. we adopt each device manager to control efficiently. we demonstrate a proposed system works properly with user behavior such as gestures, motions, gazes, and voices.

• Journal of the Ergonomics Society of Korea
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• v.31 no.4
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• pp.475-481
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• 2012

Objective: The aim of this study is to make the taxonomy for classifying diverse touchless gestures and establish the design requirements that should be considered in determining suitable gestures during gesture-based interaction design. Background: Recently, the applicability of touchless gestures is more and more increasing as relevant technologies are being advanced. However, before touchless gestures are widely applied to various devices or systems, the understanding on human gestures' natures and their standardization should be prerequisite. Method: In this study, diverse gesture types in various literatures were collected and, based on those, a new taxonomy for classifying touchless gestures was proposed. And many gesture-based interaction design cases and studies were analyzed. Results: The proposed taxonomy consisted of two dimensions: shape (deictic, manipulative, semantic, or descriptive) and motion(static or dynamic). The case analysis based on the taxonomy showed that manipulative and dynamic gestures were widely applied. Conclusion: Four core requirements for valuable touchless gestures were intuitiveness, learnability, convenience and discriminability. Application: The gesture taxonomy can be applied to produce alternatives of applicable touchless gestures, and four design requirements can be used as the criteria for evaluating the alternatives.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1615-1620
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• 2017

The development of Virtual Reality (VR)-related technologies has resulted in the improved performance of VR devices as well as affordable price arrangements, granting many users easy access to VR technology. VR drawing applications are not complicated for users and are also highly mature, being used for education, performances, and more. For controller-based spatial drawing interfaces, the user's drawing interface becomes constrained by the controller. This study proposes hand interaction based spatial drawing system where the user, who has never used the controller before, can intuitively use the drawing application by mounting LEAP Motion at the front of the Head Mounted Display (HMD). This traces the motion of the user's hand in front of the HMD to draw curved surfaces in virtual environments.

• Archives of design research
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• v.17 no.2
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• pp.463-470
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• 2004

This paper studied tangible interaction design of VR platform and its applications that are economic In development process and cost, flexible by contents and installation conditions, and that has business potential for consumer market. The design solution uses video based virtual world and tangible interaction by motion tracking. Our platform enables a user to monitor their action and to collaborate with other users of remote place within attractive interaction feedback. We developed two design applications, Glass Xylophone 2003 and VR Class, in our platform. Glass Xylophone 2003 provides interactive music performance and helps self practice of glass xylophone. VR Class gives more serious distance learning experience with tutoring and group collaboration. They are presented in public exhibitions and tested by exhibition visitors. They showed application potential of this design solution in interactive game, distance learning, and entertainment field.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.197-202
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• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion. This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wail. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wail is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wail are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.333-337
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• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wall. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wall are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.