• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.404-413
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• 2013

In the present study, a towed underwater particle image velocimetry (PIV) system was validated in uniform flow and used to investigate the free-surface effects on the turbulent wake of a simple surface-piercing body. The selected test model was a cylindrical geometry formed by extruding the Wigley hull's waterplane shape in the vertical direction. Due to the constraints of the two-dimensional (2D) PIV system used for the present study, the velocity field measurements were done separately for the vertical and horizontal planes. Using the measured data at several different locations, it was possible to identify the free-surface effects on the turbulent wake in terms of the mean velocity components and turbulence quantities. In order to provide an accuracy level of the data, uncertainty assessment was done following the International Towing Tank Conference standard procedure.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.685-693
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• 1990

The heat transfer coefficients were calculated numerically to see the effects of radiation around the porous medium put on the flat plate at a distance from the leading edge of flat plate for the two-dimensional laminar flows. To verify the analytical model developed and invoke the heat/mass transfer analogy, an experiment was carried out using naphthalene sublimation technique. From the effects of the wake, Sherwood number is maximum around the region where the porous medium is attached. The theoretical results correspond well with the experimental results at small Darcy number. Permeability of ceramic blocks used for experiment was also measured and the Forchheimer equation is applicable in our measurement range.

• Journal of Families and Better Life
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• v.13 no.3
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• pp.124-132
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• 1995

본 연구는 Schlater와 Sontag가 인간생태학적 관점에 기초하여 제시한 가치측정 모델에 의하여 국내 가정관리학 분야에서 이루어진 인간의 가치에 관한 연구를 분류하였다. 2차원의 매트릭스로 구성된 이 모델은 가치연구를 가치조사의 초점에따라 내용과 구조, 과정으로 분류할 수 있으며, 또한 피험자-가치대상 포함관계에 따라 3가지 측정접근법 즉, 피험자 단독, 피험자-가치대상 반응적, 피험자-가치대상 상호작용적 접근법으로 분류하고 있다. 이 모델을 분석도구로 사용하여 한국 가정관리학회지 창가호부터 1995년 13권 1호까지와 대한가정학회지 1983년 21권 1호부터 1995년 33권 1호까지에 수록된 논문중 인간의 가치를 연구한 논문과 몇편의 학위논문을 분석하였다. 그 결과 대부분의 연구들은 측정접근법상 피험자 단독 접근법이나 피험자-가치대상 반응적 접근법을 사용하면서, 내용에 초점을 두고 연구된 것을 알 수 있다. 미래의 가치연구방법으로 인간생태학적 접근법인 피험자-가치대상 상호작용 접근법과 과정에 초점을 맞추는 것이 요구되며, 우리나라 가치측정패턴에서만 특히 부족한 구조에 초점을 두는 것 또한 요구되어진다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.335-341
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• 2005

The development of Shadow Moire in many kinds of methods for acquiring 3-dimensional information from an object is written in this paper. The fringe is appeared, when a grating mask makes its shadow on the object. The object is moved along x-axis more then 3 times to get phases from its fringe that contains data of the object's height. PMP{Phase Measuring Profilometry) is used for analyzing these images from a CCD camera. The calculated phase is remedied for expending the restricted results due to range of the $tan^{-1}$.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.4
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• pp.369-378
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• 2000

The objective of this study is to measures deformation of the structures for stability checks by GPS survey. In this study, 2 points on south side dike of Keum River were measured by 4 sets of GPS(SR9500, Leica) every 4 months for a year, and 3-dimensional displacements of the points were acquired. In order to seek more reliable deformation measurement methods for the offshore structure by GPS, the accuracy of GPS survey with various control points configuration and checking system for detecting unrealistic measurements are also discussed.

• Journal of Ocean Engineering and Technology
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• v.28 no.3
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• pp.209-217
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• 2014

In the present study, the water impact loads on two-dimensional symmetric and asymmetric wedges were mainly studied. The impact pressure and force were measured during a vertical drop of the symmetric and asymmetric wedges. The measured pressure was compared with analytic solutions. The measured force at a local area of the wedge was compared with the integrated pressures and analytic solutions. Some findings on symmetric and asymmetrical wedge drops are presented, and the reliability of the force sensor used for the measurement of the local impact force is discussed.

• Journal of Surface Science and Engineering
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• v.28 no.3
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• pp.123-132
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• 1995

While a nickel mesh and an expanded nickel sheet are used as current collectors for supporting active anode materials in rechargeable batteries, a porous nickel substrate is studied extensively for its 3-dimensional structure which has high capabilities for active materials and current collection. Optimum plating conditions were studied by polarization measurement. Scanning Electron Microscopy (SEM) showed that both electroless-and electro-plated nickel on an urethane substrate were highly porous and consisted of nearly spherical pores. The diameter and the channel size of the pores were found to be 300~500 $\mu\textrm{m}$ and 50~200$\mu\textrm{m}$, respectively. The shape of skeleton resembled a triangular prism with length extending about 50~100 $\mu\textrm{m}$.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.11
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• pp.99-109
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• 2004

This paper proposes precision evaluation method for the positioning error of three-DOF translational parallel mechanism. The proposed method uses conventional CMM as metrology equipment to measure the position of end-effector. In order to obtain accurate measurement data from CMM, the transform relationship between the coordinate system of the parallel mechanism and the CMM coordinate system must be identified. For this purpose, a new coordinate referencing (or coordinate system identification) technique is presented. By using this technique accurate coordinate transformation relationships are efficiently established. According to these coordinate transformation relationships, an equation to calculate error components at any arbitrary position of the end-effector is derived. In addition, mathematical fitting models to represent the position error components in the two-dimensional workspace of the parallel mechanism are also constructed based on response surface methodology. The proposed error evaluation method proves its effectiveness through the experimental results and its application to real three-DOF parallel mechanism.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.76.3-76.3
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• 2019

Intracluster stars are believed to be gravitationally bound to a galaxy cluster, however, not to individual cluster galaxies. Their presence is observed as diffuse light typically in the central region extended from the brightest cluster galaxy. The diffuse light, often referred to as intracluster light (ICL), is difficult to quantify in distant high-redshift galaxy clusters because of the significant surface brightness dimming although ICL observations in high-redshift clusters provide powerful constraints on the origin of intracluster stars. In this poster, we present ICL study of the distant galaxy cluster SPT2106-5844 at z=1.132 with Hubble Space Telescope IR imaging data. With careful control of systematics, we successfully quantify the total amount of the ICL, measure the color profile, and obtain its two-dimensional distribution. Our measurement of the high abundance of the intracluster stars in this young cluster favors the ICL formation scenario, wherein production of intracluster stars are predominantly associated with the BCG formation.

• Imaging Science in Dentistry
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• v.36 no.1
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• pp.49-54
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• 2006

Purpose : To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. Materials and Methods : One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. Conclusion : The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology.