• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.258-259
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• 2003

Flow around Savonius rotor is studied by means of the numerical simulation. Three-dimensional incompressible Navier-Stokes equations are solved numerically. Overgrid system is employed in order to enable the flow calculation of complex geometry. The basic equations in each region are solved by using the standard MAC method. The physical quantities such as the velocity and the pressure among each region are transferred through the overlapping region which is common in each region. Some numerical results of static and rotating rotor will be presented.

• Journal of Periodontal and Implant Science
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• v.51 no.5
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• pp.364-372
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• 2021

Purpose: This study aimed to clinically evaluate the efficacy of vestibuloplasty around lower molar implants using 3 different modalities: apically positioned flap alone (APF), APF with a free gingival graft (FGG), and APF with modified periosteal fenestration (mPF). Methods: Three different vestibuloplasty procedures during second-stage implant surgery were performed at the mandibular molar area in 61 patients with a shallow vestibule and insufficient keratinized tissue (KT). The clinical measurements of KT width were recorded at baseline, immediately after surgery (T0), 6 months after surgery (T6), and 12 months after surgery (T12). Soft tissue esthetic scores were measured. Results: An additional KT width gain from baseline to T12 of approximately 2 mm was obtained with FGG and mPF compared to that with APF. Shrinkage of the re-established tissue was lower with mPF and FGG than with APF, whereas the esthetic profile was better with APF and mPF than with FGG. Conclusions: Within the limitations of this study, mPF showed potential as a promising approach for vestibuloplasty around the lower molar implants compared to the traditional APF and FGG.

• The Journal of Korean Society for School & Community Health Education
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• v.9 no.1
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• pp.115-126
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• 2008

Backgrounds: The objective of school zones was to define protective areas and to keep children vulnerable to traffic accidents from the risk. The current "Rules on the Designation and Management of School Zones" included provisions on the installation of traffic safety facilities and road facilities, but they were not sufficient for children's traffic safety and there were many difficulties in applying standards to the fields. Purposes: With these problems to be solved, the present study surveyed the current state of safety facilities in school footpaths and school zones around elementary schools and suggested plans to improve them. This study studied various factors like the physical environment and the safety facilities in the school zone. Methods: The present researcher visited four elementary schools selected for this study, and surveyed safety facilities in the school zones around the elementary schools using a schedule prepared by the researcher. Results: According to the results of the case study, all of the four schools were designated as school zones, but the designation appeared nominal without sufficient safety facilities that can ensure children's safety. Based on the results of the survey, suggestions were made to improve traffic facilities in school zones and school footpaths as well as safety guidance.

• Journal of the Korean Society of School Health
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• v.17 no.2
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• pp.115-126
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• 2004

Purpose: The aim of the study is to provide information about selecting school sites for new schools in congested urban areas and to propose a method to manage harmful environments around primary and secondary schools. Method: Four schools were selected around Gilum New Town and Ilsan City. The problems were identified by counting the businesses classified as harmful and prohibited in a school zone through surveying, collecting reports from relevant sources, and asking questions of authorities in school districts. Results: It was found that many harmful businesses prohibited by the Law of School Health were present in the safe zone of schools in both Ilsan city and Gilum New Town. The school site of Bohyun Elementary School was classified as poor because there was a steep ascent at the entrance and the school was surrounded by a dangerous, steep boundary. We suggested that an education and environment assessment system by completed before the school site was selected. Conclusion: There is a urgent need to improve the approval and permission process of harmful businesses as well as regulatory standards of school site selection in the light of the shortage of land.

• Archives of Plastic Surgery
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• v.37 no.6
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• pp.769-774
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• 2010

Purpose: As the soft tissue defect around the knee is difficult to reconstruct, local flap or free flap is used. Distally based anterolateral thigh pedicled flap introduced by Zhang uses sufficient reverse flow supplied from the vascular network around the knee. We report successful reconstruction of defect around knee by this method. Methods: Four patients with skin & soft tissue defect around knee have been treated for reconstruction using the distally based anterolateral thigh pedicled flap. First, the doppler was used to check the perforator flap of the descending branch of the lateral circumflex femoral artery and to draw and dissect the perforator flap as much as needed. After the dissection, the proximal of the descending branch was clamped and checked for sufficient supply of blood flow from the reverse flow and then ligated. It was dissected along the descending branch and in order to prevent damage to the joined parts of the descending branch and the lateral superior geniculate artery, a more careful ligation was done starting from 10 cm superior to the knee. The defect was reconstructed after securing enough vascular pedicle to cover all the damaged parts. Results: Not all patients suffered from flap necrosis. In case of the patient with chronic osteomyelitis, slight venous congestion was observed right after the surgery but it disappeared the following day. All three patients had no occurences of additional complications. Conclusion: Distally based anterolateral thigh pedicled flap was enough to provide large flap for knee reconstruction. It had sufficient blood flow and vascular pedicle. It also had taken short operation time compared to the free flap operation. The distally based anterolateral thigh pedicled flap used by the authors is a very useful way of reconstructing the area around knee.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.67-71
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• 2017

Debris disks are circumstellar dust disks around main-sequence stars. They are important observational clues to understanding the planetary system formation. The zodiacal light is the thermal emission from the dust disk in our Solar system. For a comprehensive understanding of the nature and the evolution of dust disks around main-sequence stars, we try a comparative study of debris disks and the zodiacal light. We search for debris disks using the AKARI mid-infrared all-sky point source catalog. By applying accurate flux estimate of the photospheric emission based on the follow-up near-infrared observations with IRSF, we have improved the detection rate of debris disks. For a detailed study of the structure and grain properties in the zodiacal dust cloud, as an example of dust disks around main-sequence stars, we analyze the AKARI mid-infrared all-sky diffuse maps. As a result of the debris disks search, we found old (>1 Gyr) debris disks which have large excess emission compared to their age, which cannot be explained simply by the conventional steady-state evolution model. From the zodiacal light analysis, we find the possibility that the dust grains trapped in the Earth's resonance orbits have increased by a factor of ~3 in the past ~20 years. Combining these results, we discuss the non-steady processes in debris disks and the zodiacal light.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.2
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• pp.87-96
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• 2020

Recently, due to the child-friendly city project being conducted by UNICEF, the movement to create a child-friendly cities has been actively promoted by the South Korean government. However, due to the lack of specific physical plans to improve the basic rights of children in the city, the project has been mainly implemented for educational and institutional projects. In this study, we investigated the activities of children and parents living in elementary school neighborhoods. Based on our investigation, we attempted to generate the desired results that can be referred to by physical planners looking to make changes to school neighborhoods by comparing and analyzing children and parents' activity range and life patterns in the neighborhood. The GPS and traffic log surveys were conducted as the primary research methods. The results of this study are as follows: First, both children and parents are most likely to walk in their neighborhoods. In addition, the use of private cars and school vehicles was high, but the use of public transportation was low. Second, the longer parents and children stayed together, the wider the range of their activities. Third, children who spent a lot of time with parents were more likely to have diverse life patterns than children who did not spend a lot of time with parents. Fourth, parents who live in elementary school neighborhoods frequently used commercial facilities and cultural centers around the school. Therefore, it is important to construct facilities around the school for parent-use.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.7
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• pp.921-929
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• 2011

We measured experimentally the properties of fluid dynamics, velocity fields, and the pressure, around stenotic obstruction located inside a circular channel structure. Particle image velocimetry system was employed to obtain velocity fields at the central section of the circular channel in the streamwise direction. The stenosis model used was made of acrylic material with different stenotic aspect ratios. The working fluid was water and it was returned by a centrifugal pump system. Pressure measurements were carried out to validate the effect of a narrow passageway. Results showed that the acceleration of gap flow through stenotic obstruction and the pressure drop in the recirculation regime behind the stenosis model can be observed.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.293-298
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• 2005

Osseointegrated prosthetic auricular reconstruction can be classified as either direct or indirect. In the $Br{\aa}nemark $ system of direct osseointegration, implants are placed into the mastoid process of the temporal bone. In the Epitec system of indirect osseointegration, implants are inserted into a three-dimensional carrier plate that is fixed to the mastoid by means of screws. We experienced forty-four cases using the indirect system and seventeen cases using the direct system. We compared with two systems by complications, such as skin reaction, implant loosening, implant loss. There were no specific differences in the skin reaction around the implants and abutments in relation to age or system used. The degree of skin reaction was different according to the conditions around the implant: in cases of virgin microtia, a skin flap was used to cover the implant, in contrast to grafted skin coverage for failed autogenous reconstruction. In both systems, the skin reaction was more severe and frequent in skin flap than in grafted skin. Loosening of the implant was more frequent in the direct system; however, accidental detachment of the implant from the abutment was more frequent in the indirect system. To reduce complications of skin reaction in osseointegrated prosthetic auricular reconstruction, it is important for soft tissue around implant to immobilize. Therefore, grafted skin is better than skin flap as soft tissue around implant. And immobilization of soft tissue around implant by wound dressing is major facter.

• Wind and Structures
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• v.37 no.1
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• pp.25-38
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• 2023

Due to the complexity and difficulty in meeting the multiphase flow complexity, similarity, and multiscale characteristics, the mechanism of snow drift is so complicated that the snow deposition prediction is still inaccurate and needs to be far improved. Meanwhile, the validation of prediction methods is also limited due to a lack of field-measured data about snow deposition. To this end, a field measurement activity about snow deposition around a cube with time was carried out, and the snow accumulation process was measured under blowing snow conditions in northwest China. The maximum snow depth, snow profile, and variation in snow depth around the cube were discussed and analyzed. The measured results indicated three stages of snow accumulation around the cube. First, snow is deposited in windward, lateral and leeward regions, and then the snow depth in windward and lateral regions increases. Secondly, when the snow in the windward region reaches its maximum, the downwash flow erodes the snow against the front wall. Meanwhile, snow range and depth in lateral regions have a significant increase. Thirdly, a narrow road in the leeward region is formed with the increase in snow range and depth, which results in higher wind speed and reforming snow deposition there. The field measurement study in this paper not only furthers understanding of the snow accumulation process instead of final deposition under complex conditions but also provides an important benchmark for validating prediction methods.