• Computers and Concrete
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• v.4 no.4
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• pp.285-298
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• 2007

Corrosion of Reinforcement (rebar) is nondestructively estimated by the half-cell potential measurement. As is the case with other nondestructive testings (NDT), understanding of the underlying principles should be clarified in order to obtain meaningful results. Therefore, the measurement of potentials in concrete is analytically investigated. The effect of internal defects on the potentials measured is clarified numerically by the boundary element method (BEM). Thus, a simplified inversion by BEM is applied to convert the potentials on concrete surface to those on rebars, taking into account the concrete resistivity. Because the potentials measured on concrete surface are so sensitive to moisture content, concrete resistivity and surface condition, an inverse procedure to convert the potentials on concrete surface into those on rebars is developed on the basis of BEM. It is found that ASTM criterion is practically applicable to estimate corrosion from the potential values converted. In experiments, an applicability of the procedure is examined by accelerated corrosion tests of reinforced concrete (RC) slabs. For practical use, the procedure is developed where results of IBEM are visualized by VRML (Virtual Reality modeling Language) in three-dimensional space.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.89-95
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• 2022

A method for measuring the length and slope of a temporary structure using an unmanned aerial vehicle (UAV) and 3D modeling method is proposed. The actual length and slope of the vertical member of the specimen were measured and compared with the measured values obtained by the proposed method for the specimens with and without the vertical protection net installed. Based on the result of measuring the length of the temporary structure specimen using the UAV and 3D modeling method, the measured value showed an error of 0.87% when compared to the actual length in the specimen without the vertical protection net installed. In addition, the error of the slope was 0.63°. It was thought that the proposed method could be usable for the purpose of finding parts in wrong installation state on the temporary structure and informing the manager in charge. However, in the case of the specimen with the vertical protection net, the measurement showed a 1.46% error in length and 2.77° difference in slope. Therefore, if a vertical protection net is to be installed in a temporary structure, the measurement accuracy should be improved by utilizing an image processing method, etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.285-297
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• 2015

In this paper, Ulta-WideBand (UWB) channel measurement and modeling based on compressive sampling (CS) are proposed. The sparsity of the channel impulse response (CIR) of the UWB signal in frequency domain enables the proposed channel measurement to have a low-complexity and to provide a comparable performance compared with the existing approaches especially used for the indoor geo-localization purpose. Furthermore, to improve the performance under noisy situation, the soft thresholding method is also investigated in solving the optimization problem for signal recovery of CS. Via numerical results, the proposed channel measurement and modeling are evaluated with the real measured data in terms of location estimation error, bandwidth, and compression ratio for indoor geo-localization using UWB system.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.412-416
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• 2001

Among water quality models, WASP5 was applied to Boryeong freshwater lake, as a part of Water Quality Management System. The WASP modeling system is a generalized modeling framework for contaminant fate and transport in surface waters. The simulated result was compaired with actual measurement. So, before and after making freshwater lake were compaired. After this research, the lake may have eutrophication and water quality would be worse after making the lake as freshwater lake. Therefore, to make the freshwater lake better, more appropriate plan is necessary.

• Journal of Power Electronics
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• v.11 no.1
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• pp.59-63
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• 2011

This paper presents the modeling of the sampling effect in the p-type average current mode control. The prediction of the high frequency components near half of the switching frequency in the current loop gain is given for the p-type average current mode control. By the proposed model, the prediction accuracy is improved when compared to that of conventional models. The proposed method is applied to a buck converter, and then the measurement results are analyzed.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.2
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• pp.31-36
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• 1999

An efficient method for thermal modeling of QFP is Proposed. Thermal measurement data are given to verify the method. In parallel with the experiment, an exact full 3-D model calculation is also provided. One fonds that there is an excellent agreement between validation data and the efficient model data.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2001.05a
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• pp.121-123
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• 2001

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.201-210
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• 1999

One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric and thermal errors of the machine tools. Therefore, a key requirement for improving te machining accuracy and product quality is to reduce the geometric and thermal errors of machine tools. This study models geometric error for error analysis and develops on-machine measurement system by which the volumetric erors are measured. The geometric error is modeled using form shaping function(FSF) which is defined as the mathematical relationship between form shaping motion of machine tool and machined surface. The constant terms included in the error model are found from the measurement results of on-machine measurement system. The developed on-machine measurement system consists of the spherical ball artifact (SBA), the touch probe unit with a star type stylus, the thermal data logger and the personal computer. Experiments, performed with the developed measurement system, show that the system provides a high measuring accuracy, with repeatability of ${\pm}2{\mu}m$ in X, Y and Z directions.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1770-1773
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• 1991

In this paper we present one modeling system, which is composed of a 3-dimensional proile measurement unit, a CAD system and a NC milling machine. This system is compactly combined so that measurement, designing and manufacturing can be performed efficiently. This system was actually applied to make a plaster model of the pottery.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.389-393
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• 2003

This paper presents circuit modeling and characterization of silicon-based on-chip integrated inductors in Giga Hertz range for wireless communication products. We compare several different designs of on-chip inductors for self-resonant frequency and quality factor. The measurement data could be used as a design guide for manufacturing practical spiral inductors for wireless applications. We provide the equivalent inductor circuit parameters from the actual measurement data.