• Korean Journal of Computational Design and Engineering
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• v.21 no.2
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• pp.159-169
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• 2016

In order to realize the virtual prototyping (VP) of digital products, it is important to provide the people involved in product development with the appropriate visualization and interaction of the products, and the vivid simulation of user interface (UI) behaviors in an interactive 3D virtual environment. In this paper, we propose an approach to web-based 3D virtual experience using Unity and Leap Motion. We adopt Unity as an implementation platform which easily and rapidly implements the visualization of the products and the design and simulation of their UI behaviors, and allows remote users to get an easy access to the virtual environment. Additionally, we combine Leap Motion with Unity to embody natural and immersive interaction using the user's hand gesture. Based on the proposed approach, we have developed a testbed system for web-based 3D virtual experience and applied it for the design evaluation of various digital products. Button selection test was done to investigate the quality of the interaction using Leap Motion, and a preliminary user study was also performed to show the usefulness of the proposed approach.

• Journal of Internet of Things and Convergence
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• v.2 no.2
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• pp.1-6
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• 2016

Recently, various types of wearable computers have been studied. In this paper, we analyze the characteristics of head motion information for the operation of the motion classifier produced motion headset that the user can use while listening to music. The prototype receives music from smart phone over bluetooth communications, and transmits the motion information measured by the acceleration sensor to the smart phone. And the smartphone classifies the motion of the head through a motion classifier. we implemented a prototype for our experiment. The user's head motion "up", "down", "left" and "right" were classified using a Bayesian classifier. As a result, in case of the movement of the head "up" and "down", there are a large changes in the x, z-axis values. In future we have a plan to perform a user study to find suitable variables for creating motion classifier.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.323-324
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.733-734
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.179-180
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• 2006

• Journal of Drive and Control
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• v.17 no.3
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• pp.76-84
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• 2020

• Korean Journal of Computational Design and Engineering
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• v.20 no.1
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• pp.65-74
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• 2015

Structure and/or fluid analysis is gradually increased by an essential design process in the small and medium-sized businesses (SMBs) because of the needs for a rapid design process and the certification about the supplement of the parts by the large business (LB). In this paper, we developed the web-based ezSIM platform installed in the resources integrated system server. The ezSIM platform is based on the heterogeneous linux and windows operating system for the user-friendly connection with the part of the analysis for the SMBs. The procedure of the structure/fluid analysis service module using the public software and the license-free open code in the ezSIM platform was explained. The convenience of the ezSIM platform service was presented by the reaction rate of the graphic motion compared with that of a local PC and the solving and pre-post processing interface compared with that of the KISTI supercomputer. The web-based ezSIM platform service was identified as a useful and essential platform to the SMBs for the usage of the structure and/or fluid analysis procedure.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.8
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• pp.639-648
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• 2002

The stewart platform manipulator is a manipulator that has the closed-loop structure with an upper plate end-effector and a base frame. The stewart platform manipulator has the merit of high working accuracy and high stiffness compared with a serial manipulator. However, this is a complex structure, so controllability of the system is not so good. In this paper, we introduce a new robust motion control algorithm using partial state feedback for a class of nonlinear systems in the presence of modelling uncertainties and external disturbances. The major contribution of this work introduces the development and design of robust observer for the state and the perturbation, which is integrated into a variable structure controller(VSC) structure. The combination of controller/observer improves the control performance, because of the robust routine called sliding mode control with sliding perturbation observer(SMCSPO). Simulation and experiment are performed to apply to the manipulator. And their results show a high accuracy and a good performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1982-1992
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• 1999

This paper presents a novel concept of cargo handling system adapted for a sea port subjected to severe time-varying tide. The proposed system can perform loading or unloading by using a sort of hydraulic elevator associated with real-time position control. In order to achieve a proof-of-concept, a small-sized laboratory model of the cargo handling system is designed and built. The model consists of three principal components container palette transfer (CPT) car, platform with lifting columns, and cargo ship. The platform activated by electro-rheological (ER) valve-cylinders is actively controlled to track the position of the cargo ship subjected to be varied due to the time-varying tide and wave motion. Following the derivation of the dynamic model for the platform and cargo ship motions, an appropriate control scheme is formulated and implemented. The location of the CPT car is sensed by a set of photoelectric switches and controlled via sequence controller. On the other hand, a sliding mode controller (SMC) is adopted as the position controller for the platform. Both simulated and measured control results are presented to demonstrate the effectiveness of the proposed cargo system.

• Ocean Systems Engineering
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• v.8 no.3
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• pp.329-343
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• 2018

The inclination of seabed profile (sloped seabed) is one of the known topographic features which can be observed at different seabed level in the large offshore basin. A mooring system connected between the platform and global seabed is an integral part of the floating structure which tries to keep the floating platform settled in its own position against hostile sea environment. This paper deals with an investigation of the motion responses of an FPSO platform moored on the sloped seabed under the combined action of wave, wind and current loads. A three-dimensional panel discretization method has been used to model the floating body. To introduce the connection of multi-segmented non-linear elastic catenary mooring cables with the sloped seabed, a quasi-static composite catenary model is employed. The model and analysis have been completed by using hydrodynamic diffraction code AQWA. Validation of the numerical model has been successfully carried out with an experimental work published in the latest literature. The analysis procedure in this study has been followed time domain analysis. The study involves an objective oriented investigation on platform motions, in order to identify the effects of the slopped seabed, the action of the wave, wind and current loads and the presence of riser system. In the end, an effective analysis has been performed to identify a stable mooring model in demand of reducing structural responses of the FPSO.