• International Journal of Concrete Structures and Materials
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• v.10 no.2
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• pp.189-203
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• 2016

This paper investigates on the use of advanced optical measurement methods, i.e. 3D coordinate measurement machines (3D CMM) and stereo-vision digital image correlation (3D DIC), for the mechanical analysis of shear deficient prestressed concrete members. Firstly, the experimental program is elaborated. Secondly, the working principle, experimental setup and corresponding accuracy and precision of the considered optical measurement techniques are reported. A novel way to apply synthesised strain sensor patterns for DIC is introduced. Thirdly, the experimental results are reported and an analysis is made of the structural behaviour based on the gathered experimental data. Both techniques yielded useful and complete data in comparison to traditional mechanical measurement techniques and allowed for the assessment of the mechanical behaviour of the reported test specimens. The identified structural behaviour presented in this paper can be used to optimize design procedure for shear-critical structural concrete members.

• Journal of Ocean Engineering and Technology
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• v.17 no.4
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• pp.1-7
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• 2003

A virtual reality technology for multipurpose numerical simulation is developed to reproduce and investigate a variety of ocean environmental problems in a 3D Numerical Wave Tank(NWT). The governing equations for solving incompressible fluid motion are Navier-Stokes equation and continuity equation. The Marker-Density function technique is adopted to implement the fully nonlinear freesurface kinematic condition. The marine environmental situations, i.e., waves, currents, etc., are reproduced by use of multi-segmented wavemakers on the basis of the so-called ″snake-principle″. In this paper, some numerical reproduction techniques for regular, and irregular waves, multi-directional waves, Bull's-eye wave. wave-current, and solitary wave are presented, and a model test in motion with large amplitude of roll angle is conducted in the developed 3D-NWT, using a overlaid grid system.

• Journal of Mechanical Science and Technology
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• v.18 no.6
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• pp.879-894
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• 2004

The image processing technique is simple and, in principle, can handle particles with various shapes since it is based on direct visualization. Moreover, a wide measurement area can be covered with appropriate optical arrangement. In the present paper, various techniques of image processing for sizing and counting particles are reviewed and recent developments are introduced. Two major subjects are discussed in detail: identification of particles (i.e., boundary detection and pattern recognition) and determination of in-focus criteria. Finally, an overall procedure for image processing of spray particles is suggested.

• Journal of Engineering Education Research
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• v.15 no.1
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• pp.72-78
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• 2012

This paper deals with metaphysical aspects of responsibility focusing on Hans Jonas's Das Prinzip Veranwortung as an attempt to further the discussion on the responsibility of scientists and engineers. After the examination on the necessity of new ethics reflecting the characteristics of contemporary science and technology, the philosophical foundation and major themes of Jonas's future-oriented ethics, i.e. responsibility ethics are analysed. Jonas argued new ethics should consider man and nature simultaneously based on the unification of being and what should be, and presented collectivity, continuity, and future-orientation as a basis of responsibility ethics. In conclusion, this paper suggests implications of Jonas's argument for science and technology ethics such as sustainability, precautionary principle, and responsibility of creator.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.31.4-32
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• 2008

The microwave instruments are used many areas of the space remote sensing and space science applications. The imaging radar of synthetic aperture radar (SAR) is well known microwave radar sensor for earth surface and ocean research. Unlike radar, microwave radiometer is passive instrument and it measures the emission energy of target, i.e. brightness temperature BT, from earth surface and atmosphere. From measured BT, the geophysical data like cloud liquid water, water vapor, sea surface temperature, surface permittivity can be retrieved. In this paper, the radiometer characteristics, system configuration and principle of BT measurement are described. Also the radiometer instruments TRMM, GPM, SMOS for earth climate, and ocean salinity research are introduce. As first korean microwave payload on STSAT-2, the DREAM (Dual-channels Radiometer for Earth and Atmosphere Monitoring) is described the mission, system configuration and operation plan for life time of two years. The main issues of DREAM unlike other spaceborne radiometers, will be addressed. The calibration is the one of main issues of DREAM mission and how it contribute on the space borne radiometer. In conclusion, the radiometer instrument to space science application will be considered.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.304-307
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• 2008

A spreadsheet-based linear program (LP) software, so called, the LP-Tableau is developed to aid users to learn the simplex algorithm systematically and to understand the various conditions that make the problem unusual and, in some instances, impossible to solve. The LP-Tableau has several good features over other spreadsheet-based LP software programs available. First, the data input in the LP-Tableau is very convenient especially when small-sized problems are analyzed. Further, the LP-Tableau allows for two solution methods (i.e., Big-M and Two-Phase) and displays the whole iterations in tableau format. Thus users can easily understand the principle of the algorithm step by step. Finally, the LP-Tableau visually displays various conditions of the optimal solutions that might occur in solving the LP problems.

• Journal of Intelligence and Information Systems
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• v.3 no.1
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• pp.69-81
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• 1997

In this paper, first we propose an architecture of fuzzy neural networks with triangular fuzzy weights. The proposed fuzzy neural network can handle fuzzy input vectors. In both cases, outputs from the fuzzy network are fuzzy vectors. The input-output relation of each unit of the fuzzy neural network is defined by the extention principle of Zadeh. Also we define a cost function for the level sets(i. e., $\alpha$-cuts)of fuzzy outputs and fuzzy targets. Then we derive a learning algorithm from the cost function for adjusting three parameters of each triangular fuzzy weight. Finally, we illustrate our a, pp.oach by computer simulation examples.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.570-574
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• 2004

This paper deals with a novel 3-phase power quality disturbance generator. The proposed generator can be applied to the performance that of custom power devices. Voltage sag, swell, outage unbalance and phase shift are provided by the generator. The control scheme for the disturbance generation is simple, and hardware setup is cost effective compared with conventional scheme. The operating principle of the generator is described and the usefulness verified through simulation with 10kVA power rating.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.592-596
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• 2004

This paper deals with the operation of a flywheel energy storage UPS. The ups has good features such as long life-time, improved efficiency, no environment problems, reduced size and space, and low maintenance cost compared with the conventional UPS using battery. The operating principle of the UPS is analysed in each mode including charging, voltage compensation, discharging, and voltage unbalance compensation. Especially, the tracking characteristic of the disturbed phase of the source voltage after outage is analysed. The usefulness of the operation is proved through simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1322-1327
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• 2005

This paper presents a single-stage ZVT full-bridge AC/DC converter for aerospace applications. The detailed operating principle and design consideration of this soft-switched converter are analyzed and described. The proposed circuit topology and control scheme are proposed to exhibit optimum performances (i.e. high power factor, high efficiency, ring-free and low EMI features). A laboratory prototype, 500W 5V/100A AC/DC converter was implemented. The simulation and experimental waveforms verify the feasibility of the proposed design.