• Bulletin of the Korean Mathematical Society
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• v.59 no.6
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• pp.1595-1603
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• 2022

We show how some of well-known recurrent operators such as recurrent curvature operator, recurrent Ricci operator, recurrent Jacobi operator, recurrent shape and Weyl operators have the significant role for biharmonic hypersurfaces to be minimal in the Euclidean space.

• The Journal of the Korea Contents Association
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• v.12 no.10
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• pp.138-147
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• 2012

Recently, significant tries appeared in the spatial design field were appreciated as tries to find crossing between space formation and discourse. This study is to find spatial clues from Gilles Deleuze, the modern philosopher's literature where he developed his discourse analyzing paintings of Francis Bacon, and reveal common characteristics with the contemporary spatial design. According to the analysis of Deleuze, Bacon's paintings are separated into frame-aplat, shape-figure, and contour-track. From these three elements, I extracted spatially analyzing languages of 'occurrence of shape-accident', 'space of track-sense', and 'interaction of aplat-background.' Then with these analyzing languages, I analyzed latest works of Rem Koolhaas. Deleuze Space Theory confirmed in works of Rem Koolhaas is the application of accident-focused occurred between the user and space, the space that induces accident, and differentiation between the user and space or space and site. As a result, I could confirm the common characteristic that both modern discourse and spatial design are understood as 'difference' from life and movement.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.177-184
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• 2005

The 21st Century Museum of Contemporary Art, Kanazawa as a regional public culture facility is the place where it is possible to think over the roles and meanings of a museum. The urn of this research is to provide information for exploring a desirable direction of the design of a regional museum by analyzing the architectural meanings and public property of the 21st Century Museum of Contemporary Art, Kanazawa. In addition, we arranged the totes and meanings of a regional museum and the concept of the public property in architecture. We also analyzed the architectural quality and the expression of the public property in this museum, as well as the value and meaning of a museum through field researches. The results of this research are as follows. First, this museum breaks with the existing stereotyped Idea to be a space open to the citizens. It secures a wide public space and provides the convenience of access and every facility for citizens. Second, the floor plan is divided into the interchanging area for citizens and an exhibition area; the outskirts of the inside of the museum are planned to be used free of charge for an interchanging space of citizens as a public-owned space of citizens. Third, the public-owned space of citizens includes a citizen exhibition hall, an art library, a kids studio and rest space, which ate all designed lot everyone to enjoy freely. Last, the exterior shape of the museum is simple but harmonize with the surroundings. It has an unique shape showing the local identity, and its most special properties are the convenience of access, introduction of a free space inside, and security of a huge space for children and citizens.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1021-1030
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• 2023

We propose an overall procedure for measuring and unfolding fast neutron spectra using a trans-stilbene scintillation detector. Detector characterization was described, including the information on energy calibration, detector resolution, and nonproportionality response. The digital charge comparison method was used for the investigation of neutron-gamma Pulse Shape Discrimination (PSD). A pair of values of 600 ns pulse width and 24 ns delay time was found as the optimized conditions for PSD. A fitting technique was introduced to increase the trans-stilbene Proton Response Function (PRF) by 28% based on comparison of the simulated and experimental electron-equivalent distributions by the Cf-252 source. The detector response matrix was constructed by Monte-Carlo simulation and the spectrum unfolding was implemented using the iterative Bayesian method. The unfolding of simulated and measured spectra of Cf-252 and AmBe neutron sources indicates reliable, stable and no-bias results. The unfolding technique was also validated by the measured cosmic-ray induced neutron flux. Our approach is promising for fast neutron detection and spectroscopy.

• Journal of Periodontal and Implant Science
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• v.43 no.4
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• pp.160-167
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• 2013

Purpose: This study examined the factors that can be associated with the appearance of the interproximal papilla. Methods: One hundred and forty-seven healthy interproximal papillae between the maxillary central incisors were examined. For each subject, a digital photograph and periapical radiograph of the interdental embrasure were taken using a 1-mm grid metal piece. The following parameters were recorded: the amount of recession of the interproximal papilla, contact point-bone crest distance, contact point-cemento-enamel junction (CEJ) distance, CEJ-bone crest distance, inter-radicular distance, tooth shape, embrasure space size, interproximal contact area, gingival biotype, papilla height, and papilla tip form. Results: The amount of recession of the interproximal papilla was associated with the following: 1) increase in contact point-bone crest, contact point-CEJ, and CEJ-bone crest distance; 2) increase in the inter-radicular distance; 3) triangular tooth shape; 4) decrease in the interproximal contact area length; 5) increase in the embrasure space size; and 6) flat papilla tip form. On the other hand, the amount of gingival recession was not associated with the gingival biotype or papilla height. In the triangular tooth shape, the contact point-bone crest distance and inter-radicular distance were longer, the interproximal contact area length was shorter, and the embrasure space size was larger. The papilla tip form became flatter with increasing inter-radicular distance and CEJ-bone crest distance. Conclusions: The relative position of the interproximal papilla in healthy subjects was associated with the multiple factors and each factor was related to the others. A triangular tooth shape carries a higher risk of recession of the interproximal papilla because the proximal contact point is positioned more incisally and the bone crest is positioned more apically. This results in an increase in recession of the interproximal papilla and flat papilla tip form.

• Korean Institute of Interior Design Journal
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• no.39
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• pp.37-44
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• 2003

From long time ago, stairs are performed the central role of vertical circulation system in architectural planning for convenience of human. The purpose of this study is to find the spacial characteristics of stairs in architectural space. Two methods In this study are discussed. First, it is to extract the formal elements in its stairs shape raising an impulse of visual-perceptible recognition. Second, it is to analysis its characteristic through relationship between stairs and spacial elements. In conclusion, the characteristics of stairs in architectural space have as follows 1) spatial connection - to connect between space and other space or masses; 2) spatial separation - to separate between inner space and other space; 3) openness or closeness of space; 4) directed-tention of space.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.4
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• pp.43-50
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• 2013

This study is to clarify the characteristics and its change of spatial elements for community focused on the existing 22 old settlements in urban area of Cheongju. These community spaces are mainly divided into three parts, that is central space, inner road, and blind alley(cul-de-sac). The transitional characteristics of them are as follows. Firstly, the characteristics of central spaces is lasting, but the function is influenced by changing times. The function of central spaces located at the entrance to the village had been reduced to adjustments to modern lifestyle, and currently changed into senior citizen community center, supermarket, and public area. Secondly, as the width of the existing inner roads passed through old settlements had been extended, they are changed into pedestrian and traffic road, but the shape and function of them have been maintained. When new roads passed through old settlements had been established, the shape of old inner roads is disappeared, and the function of them is changed into byway and alley. Thirdly, cul-de-sacs of old settlements have tended to create a sense of community, but new cul-de-sacs formed by lot division have been only changed to passage. When new roads are established and cul-de-sacs are changed into alleys, the community between individual households is lost.

• Journal of Powder Materials
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• v.18 no.6
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• pp.488-495
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• 2011

This study was performed to fabricate the porous titanium foam by space holder method using NaCl powder, and to evaluate the effect of NaCl volume fractions (33.3~66.6 vol.%) on the porosities, compressive strength, Young's modulus and permeability. For controlling pore size, CP titanium and NaCl particles were sieved to different size range of 70~150 ${\mu}m$ and 300~425 ${\mu}m$ respectively. NaCl of green Ti compact was removed in water followed by sintered at $1200^{\circ}C$ for 2 hours. Total porosities of titanium foam were in the range of 38-70%. Pore shape was a regular hexahedron similar that of NaCl shape. Porous Ti body showed that Young's modulus and compressive strength were in the range of 0.6-6 GPa and 8-127 MPa respectively. It showed that pore size and mechanical properties of Ti foams was controllable by NaCl size and volume fractions.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.52.2-53
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• 2017

We develop a methodology to use the redshift dependence of the galaxy 2-point correlation function (2pCF) as a probe of cosmological parameters. The positions of galaxies in comoving Cartesian space varies under different cosmological parameter choices, inducing a redshift-dependent scaling in the galaxy distribution. This geometrical distortion can be observed as a redshift-dependent rescaling in the measured 2pCF. The shape of the 2pCF exhibits a significant redshift evolution when the galaxy sample is analyzed under a cosmology differing from the true, simulated one. Other contributions, including the gravitational growth of structure, galaxy bias, and the redshift space distortions, do not produce large redshift evolution in the shape. We show that one can make use of this geometrical distortion to constrain the values of cosmological parameters governing the expansion history of the universe. This method could be applicable to future large scale structure surveys, especially photometric surveys such as DES, LSST, to derive tight cosmological constraints. This work is a continuation of our previous works as a strategy to constrain cosmological parameters using redshift-invariant physical quantities.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.5
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• pp.517-528
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• 2012

Inserting a nozzle assembly into a removed cutting space during a continuous cutting operation is necessary in rock excavation using an abrasive waterjet. In this study, a combined two nozzle assembly is used to secure enough removal width. The shape of the cut space is affected by the geometric parameters (standoff distance, nozzle angle, and vertical distance between the nozzle tips) of the combined nozzle assembly. Abrasive waterjet cutting tests are performed with various geometric parameters for granite rock specimens. Optimized geometric parameters for the nozzle inserting process are determined and verified through the experimental tests.