• Economic and Environmental Geology
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• v.39 no.2 s.177
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• pp.163-171
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• 2006

This study is the case of groundwater development based on the geometrical fracture model of target area established only through geological fracture mapping technique. A fracture mapping of $9km^2$, eastern Munsan, has been conducted to determine geological and hydrological factors for new water well placement in the Gyeonggi gneiss complex. Geophysical exploration was not applicable because of small restricted area and dense underground utilities at the site. Form line mapping on the basis of foliation orientation and rock type revealed a synform of NS fold axis bearing to the south. An EW geological cross-section passed through the site area shows a F2 synform as a double-wall ice cream spoon shape. Three regional faults of $N20^{\circ}E,\;N30^{\circ}W$, and NS have been dragged into the site to help understand extensional fault paths. The $N20^{\circ}E$ fault with dextral sense is geometrically interpreted as a western fault of two flexural conjugate type-P shear faults in the F2 synformal fold. The NE cross-section reveals that a possible groundwater belt in the western limb of super-posed fold area is formed as a trigonal prism within 100 m depth of the intersectional space between the $N20^{\circ}E$ fault plane and the weakly sheared plane of transposed foliation. Another possible fault for water resource strikes $N40^{\circ}E$. Recommended sites for new water well placement are along the $N20^{\circ}E\;and\;N40^{\circ}E$ faults. As a result of fracture mapping, 145 ton/day of water can be produced at one well along the $N20^{\circ}E$ fault line. Exploration of groundwater in the area is succeeded only using with geological fracture mapping and interpretation of geological cross-section, without any geophysical survey. Intersection of fault generated with the F2 synformal fold and foliation supply space of groundwater reserver.

• Journal of Korea Water Resources Association
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• v.49 no.12
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• pp.1035-1044
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• 2016

In joint portions of the levee and the barrier, complex 3-dimensional flow was generated and collapse of revetment occurred frequently. For these reasons, it is necessary to install the joint revetment with greater stability as compared with the general revetment at the joint portions. However, design criteria for joint revetment was not presented in River Design Criteria (KWRA, 2009). Therefore it is necessary to research for engineering design of the joint revetment. In this study, hydraulic experiments were performed under various flow conditions in order to realize the collapse conditions of riprap and carried out in 20.0 m straight open channel with one side levee and the width was 4.0 m. The diameter of riprap covered around joint revetment was 0.03 m and the inlet discharges were $0.5{\sim}0.8m^3/s$. The numerical simulations were performed under same conditions with experiment. as results of this numerical simulations, the influence range was confirmed from the distribution of flow characteristics and shear stress. As a result, the riprap diameter of the joint revetment was calculated from 4.1 to 6.9 times greater than that of general revetment. As the inlet discharge was large, the range of vulnerable area was developed long in the downstream direction despite of same withdrawal velocity of riprap. Through this study, the methods of calculating the riprap diameter and influence range were proposed according to hydraulic characteristics of flow around joint revetment. At a later study, if additional experiments about effect of flood plane and various types of barrier is applied, it is expected that rational design method with stability of joint revetment can be proposed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.1
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• pp.21-30
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• 2004

This study deals with free vibrations of laminated composite structures with a channel section using finite element method. In this paper, the mixed finite element method using Lagrangian and Hermite interpolation functions is adopted and a high-order plate theory is used to analyze laminated composite non-prismatic folded plates with a channel section more accurately for free vibration. The theory accounts for parabolic distribution of the transverse shear stress and requires no shear correction factors supposed in the first-order plate theory. An 32×32 matrix is assembled to transform the system element matrices from the local to global coordinates using a coordinate transformation matrix, in which an eighth drilling degree of freedom (DOF) per node is appended to the existing 7-DOF system. The results in this study are compared with those of available literatures for the conventional and first-order plate theory. Sample studies are carried out for various layup configurations and length-thickness ratio, and geometric shapes of plates. The significance of the high-order plate theory in analyzing complex composite structures with a channel section is enunciated in this paper.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2
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• pp.68-77
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• 2005

The purpose of a spatial audio system is to give a listener an impression as if he were present in a recorded environment when its sound is reproduced. For this purpose a dummy head microphone is generally used. Because of its human-like shape, dummy head microphone can reproduce spatial images through headphone reproduction. However, its shape and size are restriction to public use and it is difficult to convert the output signal of dummy head microphone into a multi-channel signal for multi-channel environment. So, in this paper, we propose a multi-channel 3D microphone technology. The multi-channel 3D microphone acquire a spatial audio using five microphones around a horizontal plane of a rigid sphere and through post processing, it can reproduce various reproduction signals for headphone, stereo, stereo dipole, 4ch and 5ch reproduction environments. Because of complex computation, we implemented H/W based post processing system. To verily the Performance of the multi-channel 3D microphone, localization experiments were Performed. The result shows that a front/back confusion, which is the one of common limitations of conventional dummy head technology, can be reduced dramatically.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.192-198
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• 2004

A numerical method is developed to solve a two-dimensional diffraction problem for a body located in a sediment pocket where a heavier muddy water is trapped. In the present study, the wave exciting forces acting on a submerged body in the water-sediment interface by an incident wave is investigate. It is assumed that the heavier mud is trapped locally in a sediment pocket. A mathematical formulation is made in the scope of the potential theory. The fluid is assumed to be inviscid, incompressible and its motion irrotational. The boundary conditions on the unknown free surface and interface are linearized. As a method of solution, the localized finite-element method is adopted. In the method, the computation domain is reduced by utilizing the complete set of analytic solutions known in the infinite subdomain to be truncated by introduction of an appropriate juncture conditions. The main advantage of this method is that any complex geometry of the boundaries can be easily accommodated. Computations are carried out for mono-chromatic plane progressive surface waves normally incident on the domain. Numerical results are compared with those obtained by Lassiter based on Schwingers variational method. Good Agreements are obtained in general. Another numerical computations are made for the cases with and without a body in the sediment pocket.

• Progress in Superconductivity
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• v.12 no.2
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• pp.118-123
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• 2011

The properties of $2^{nd}$ generation high temperature superconducting wire, coated conductor strongly depend on the quality of superconducting oxide layer and property of metal substrate is one of the most important factors affecting the quality of coated conductor. Good mechanical and chemical stability at high temperature are required to maintain the initial integrity during the various process steps required to deposit several layers consisting coated conductor. And substrate need to be nonmagnetic to reduce magnetization loss for ac application. Hastelloy and stainless steel are the most suitable alloys for metal substrate. One of the obstacles in using stainless steel as substrate for coated conductor is its difficulties in making smooth surface inevitable for depositing good IBAD layer. Conventional method involves several steps such as electro polishing, deposition of $Al_2O_3$ and $Y_2O_3$ before IBAD process. Chemical solution deposition method can simplify those steps into one step process having uniformity in large area. In this research, we tried to improve the surface roughness of stainless steel(SUS310). The precursor coating solution was synthesized by using yttrium complex. The viscosity of coating solution and heat treatment condition were optimized for smooth surface. A smooth amorphous $Y_2O_3$ thin film suitable for IBAD process was coated on SUS310 tape. The surface roughness was improved from 40nm to 1.8 nm by 4 coatings. The IBAD-MgO layer deposited on prepared substrate showed good in plane alignment(${\Delta}{\phi}$) of $6.2^{\circ}$.

• The Journal of the Petrological Society of Korea
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• v.16 no.3
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• pp.129-143
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• 2007

We have studied orientational characteristics of microcracks in Mesozoic granites and granitic dyke rocks from Seokmo-do, Ganghwa-gun. Microcracks on horizontal surfaces of rock samples from 14 sites were investigated by image processing. Orientations of these microcracks compared with those of 18 sets of joints in Mesozoic granites from Seokmo-do. From the related chart, microcrack sets show strong preferred orientations which obviously are coincident with the direction of vertical common joints. It follows that the formation of macroscopic joints may be the results of further growth and step-wise jointing of pre-existing microcracks. Orientations of microcracks from this result also compared with those of vertical rift and grain planes for Jurassic and Cretaceous granite quarries in Korea. As shown in the distribution chart, the congruence of distribution pattern among microcracks and rift and grain planes suggests that similar microcrack systems probably occur regionally in Jurassic and Cretaceous granites from Korea. In particular, whole domain of the distribution chart was divided into 16 groups in terms of the phases of distribution of microcracks and planes. These microcrack sets in each domains construct complex composite microcrack systems which have formed progressively by different geologic processes and under varying conditions.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.95-105
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• 2001

The present study was designed to compare morphological and structural relationships between basicranial measurements such as MCF angulation (Ar-SE-ptm), saddle angle (N-S-Ba, N-S-Ar) and facial structures including types of malocclusion. Twenty six children with Class III whose longitudinal headfilms were available from 7 to 12-year-old, and also 26 cross-sectional headfilms at each ages of 8, 9, 10 and 11 with Class I were selected for the investigation. Cephalometric measurements such as Ar-SE-ptm, N-S-Ba, N-S-Ar, N-SE-Ar, SNA, SNB, N-S/PM vert, CP/PM vert, $\underline{1}/FH$ plane, and $N-perp/\underline{1}$ were measured. Morphologic relationships and pattern of changes in facial structures in relation to the changes of MCF and saddle angle in both malocclusion types were analysed statistically employing ANOVA, t-test and Pearson correlation. Results suggest that the MCF rather than the saddle angle in children with Class I and III is more closely related with various facial structures and with their changes. It may be, therefore, suggested that the MCF be one of the biologically meaningful measurements in determining structural relationships between cranial base and facial complex including types of malocclusion. In addition, the MCF and its correlated facial structures in children with Class III, interestingly, showed somewhat marked changes between the ages of 9 and 11.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.253-262
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• 2017

In lateral projection imaging method of knee joint, a method that adjusts the incidence angle of central X-ray toward the head side to $5{\sim}7^{\circ}$ in true lateral position which is existing recommended is called imaging method A, Method of imaging the central X-ray perpendicular to the horizontal plane of the examination table toward the knee is called imaging method B, and a method in which the central X-ray is perpendicularly applied to the joints while the lateral side of the distal tibia is compensated by radiolucent materials is called as method C. After tests each imaging method to classified study subject respectively, the joint space distance and the distance between lateral and medial condyle of femur were measured and compared as the quantitative index from the three imaging methods. In addition, the convenience of each imaging method was confirmed through questionnaires to practician. According to the result of the quantitative index, there is no statistically significant difference in imaging method A and C(p>0.05). However, imaging method B showed a significant difference in both A and C(p<0.05). As a result of evaluating the convenience of the imaging method, imaging method A was relatively assessed lower in all items than imaging methods B and C, and as a small difference, imaging method B is assessed higher than C. In this study suggested new knee joint lateral projection imaging method, by using a simple support device, could describe joint space as not much different as existing recommended method without some complex process, and could increase convenience of the practician in the process of the imaging.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.168-175
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• 2013

Color consistency in stereoscopic contents is important for 3D display systems. Even with a stereo camera of the same model and with the same hardware settings, complex color discrepancies occur when acquiring high quality stereo images. In this paper, we propose an integrated color matching method that use cumulative histogram in global matching and estimated 3D-distance for the stage of local matching. The distance between the current pixel and the target local region is computed using depth information and the spatial distance in the 2D image plane. The 3D-distance is then used to determine the similarity between the current pixel and the target local region. The overall algorithm is described as follow; First, the cumulative histogram matching is introduced for reducing global color discrepancies. Then, the proposed local color matching is established for reducing local discrepancies. Finally, a weight-based combination of global and local matching is computed. Experimental results show the proposed algorithm has improved global and local error correction performance for stereoscopic contents with respect to other approaches.