• Journal of Creative Information Culture
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• v.5 no.3
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• pp.355-364
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• 2019

In this paper, in order to prepare a classroom model that can effectively operate SW education, this study explored cases of creative educational space construction overseas and conducted a demand survey on elementary and middle school teachers. As a result, in overseas cases, classrooms were constructed in various forms, and furniture in the classrooms were produced in various shapes and sizes, and the cases using advanced equipment were explored. As a result of the survey on the education site, it was found that the most desired installation is a fluid type that can restructure the space by freely moving the facilities according to the teaching method. The results of the analysis are expected to be of great help in rebuilding computer labs or building infrastructure for future SW training.

• The Journal of the Acoustical Society of Korea
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• v.26 no.7
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• pp.353-360
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• 2007

Rapid urbanization and population increasing are making a high-rise residential building and high-density residential area. According to spacial concentration of population is occurred road traffic noise problem. Now we are popularly using almost only noise barrier installation, but it makes many disfunctions such as poor landscape, low noise barrier performance and crimes. The purpose of this research is to figure out which is best method one the traffic noise management. Alternative are composed to building layout type ($30^{\circ},\;90^{\circ},\;180^{\circ}$), separation between road and residential building, noise barrier types(noise barrier only, noise barrier and forests and etc). The noise barrier are shown to reduce barrier and building layout angle $30^{\circ}$ position is the best comparing with horizontal and vertical layouts. The gab distance is decreased approximately noise level 5dB(A). We figured out there are noise important method except noise barrier wall and it was analyzed how much decreased. This can be very useful before making a road planning and residential building design.

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.359-372
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• 2003

Among objectives of periodontal therapy. the principal one is the morphological and functional reconstruction of lost periodontal supporting tissues. This includes de novo formation of connective tissue attachment and the regrowth of alveolar bone. The use of enamel matrix derivative(EMD) may be a suitable means of regeneration new periodontal attachment in the infrabony defects. Implant used to replace lost tooth but, implantitis occurred after installation. The purpose of this study was to investigate the effects of EMD on differentiation and growth of osteoblast in titanium disc. Twentyfive millimeter diameter and 1mm thick Ti disc which was coated 25, 50, 100, 200${\mu}g$/ml of EMD(Emdogain(R)) used as experimental group, 25, 50, 100, 200ng/d of rhBMP-2 as positive control group, and no coat as negative control group. A human osteosarcoma cell line Saos-2 was cultured in Ti disc and cell proliferation and Alkaline phosphatase (ALP) activity were measured at 1 and 6 days. PCR was performed at 2 and 8 hours. Semi-quantitative RT-PCR for mRNA expressions of various osteoblastic differentiation markers -type I collagen, ALP, osteopontin, and bone sialoprotein - were performed at appropriate concentrations based upon the results of MTT and ALP assay. Cultured cell-disc complexes were prepared for scanning electron microscopy (SEM) at 2 hour. Data were analyzed using Mann-Whitney and repeated- measures 1-way analysis of variance(SPSS software version 10,SPSS. Chicago. IL). After culture, there was more osteoblast in EMD100${\mu}g$/ml than in EMD50, 200${\mu}g$/ml on day 6. There was significant difference in experimental and positive control group compared control group, as times go by(1 and 6 days). Alkaline phosphatase activity was different significantly in EMD100, 200${\mu}g$/ml and BMP100, 200${\mu}g$/ml on day 6. The results of reverse transcriptase-polymerase chain reaction (RT-PCR) showed that expression of mRNA for ALPase, collagen type I, osteopontin. hone sialoprotein and BMP-2 was detected at 2 hour and 8 hour in EMI 200${\mu}g$/ml subgroup and BMP100ng/ml subgroup. The results of this study suggest that application of enamel matrix derivative on osteoblast attached to titanium surface facilitate the expression of bone specific protein and the differentiation and growth of osteoblast.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.49-58
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• 2020

In domestic construction sites, when installing steel pipe scaffolding and system scaffolding, the guardrails are installed after the installation of the work platforms. This conventional guardrail system (CGS) is always exposed to the risk of falls because the safety railing is installed later. In order to prevent fall disasters during erecting and dismantling scaffolds, it is necessary to introduce the advanced guardrail system (AGS) which installs railings in advance of climbing onto a work platform. For the introduction of the AGS, the structural performance of the system scaffolding applying the CGS and the AGS was compared and evaluated. The structural analysis of the system scaffold (height: 31 m and width: 27.4 m) with AGS confirmed that structural safety was ensured because the maximum stress of each element of the system scaffolding satisfies the allowable stress of each element. As a result of performance comparison of CGS and AGS for each element, the combined stress ratio of vertical posts in AGS was 6.4% lower than that of CGS. In addition, in the case of ledger and transom, the combined stress ratios of AGS and CGS were almost the same. The compression test of the assembled system scaffolding (three-storied, 1 bay) showed that the AGS had better performance than the CGS by 9.7% (8.91 kN). The cross bracing exceeds the limit on slenderness ratio of codes for structural steel design. But the safety factor for the compressive load of the cross bracing was evaluated as meeting the design criteria by securing 3 or more. In actual experiments, it was confirmed that brace buckling did not occur even though the overall scaffold was buckled. Therefore, in the case of temporary structures, it was proposed to revise the standards for limiting on slenderness ratio of secondary or auxiliary elements to recommendations. This study can be used as basic data for the introduction of AGS for installing guardrails in advance at domestic construction sites.

• Journal of agriculture & life science
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• v.43 no.2
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• pp.47-53
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• 2009

This research is intended to study the induction net of chrysanthemum used in its greenhouse and requiring lots of time for manual work and review the structural safety of a bed and existing greenhouses after designing the bed of a net which increases cropping period by sharply reducing the time of work and provides the bed of induction nets for cultivating chrysanthemum with its existing and new greenhouse. The review of sectional and biodynamic properties in 15 kinds of materials has revealed that the pipes of ${\phi}38.1{\times}1.7t$and ${\phi}38.1{\times}2.0t$ didn't exceed stress ratio but did 10mm drooping allowance. For this reason, the pipe of ${\phi}48.1{\times}1.5t$ net both stress ratio and drooping allowance. For the safety, the middle chamber should be designed into Truss type owing to bed load, wind load, and snow load when the bed of an induction net is installed in the middle chamber. When installing the middle chamber with a truss type, the greenhouse of chrysanthemum in Geochang area needs proper reinforcements because the stress in colullllls and wind proof walls exceeds stress allowance regardless of the installation of a bed.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.5
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• pp.82-91
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• 2007

Currently, bridges are regarding as the structure with formative, scenic and environmental values more than their function as simple passageways. Because an attempt to work on the diversity of the bridge types and installation of the large structures on bridge are part of the project of the regional amenity enterprises, a study that harmonizes bridges with landscape is needed at this point in time. This background can influence the direction of bridge landscapes that considers local features by analysis of visual preferences on a bridge simulated scene. The results were as follows: analyzing the change of the simulated landscape image, forest landscape are damaged by the input of a bridge which was natural, harmonic and intimate. On the other hand, when a bridge was inserted into the ocean landscape, it was thought to improve the ocean landscape, especially, upper part form of arch bridge various or suspension bridge were improved in polished and various image. The insertion of a bridge into an urban landscape change from a negative image to a beautiful, harmonic and attractive image. The intimate, harmonic and natural image of a rural landscape was damaged by inserting a bridge. As analysis result about change of landscape preference by input of bridge, there is difference between before and after as input the bridge, and bridge influences as main object in the simulated scene. Visual preference was the highest in the ocean landscape, and the lowest in the suspension bridge in the rural landscape. The complicated shape of bridge follows on the background type difference certainly appear. Thee simulated scene preference except the urban landscape of the simulated scene fell generally Especially, fall of preference of girder bridge in the forest and ocean landscape, suspension bridge in the rural landscape appeared notedly.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.3
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• pp.20-33
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• 2021

Modern society is steadily implementing policies to encourage public transportation to cope with the growing traffic demand on limited roads. The expectation is rising for transit signal priority to ensure the speed of buses as the installation of the bus rapid transit(BRT) expands nationwide to secure the competitiveness of buses. On the other hand, the form of BRT stops without considering some aspects of bus operation may increase the number of stops on the bus, thereby reducing the effectiveness of bus signal priority applications. This study suggests the type of bus stop to increase the operation efficiency of buses by analyzing the bus signal priority effect according to the BRT station type using Hannuri-daero, Sejong. The bus signal priority is used to maximize the two-way bandwidth of passenger cars and buses. As a result of the application, the effectiveness of the bus signal priority at the stop causing the double stop of the bus was reduced drastically, and the efficiency of the bus signal priority was increased significantly after improvement. These results are expected to be used as basic data in the form of proper bus stops considering the aspects of traffic operation when designing BRT stops in new towns in the future.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.5
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• pp.463-476
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• 2001

Since the treatment of edentulous patients with osseointegrated implant was first introduced more than 30 years ago, implant therapy has become one of the most important dental treatment modalities today. Based on the previous experience and knowledge, $Br{\aa}nemark\;Novum^{(R)}$ protocol was introduced with the concept of simplifying surgical and prosthetic technique and reducing healing time recently. This protocol recommends the installation of three 5mm wide diameter futures in anterior mandible and the prefabricated titanium bars for superstructure fabrication. This study was designed to analyze the stress distribution at fixture and superstructure area according to changes of fixture number, diameter and superstructure materials. Four 3-dimensional finite element models were fabricated. Model 1 - 5 standard fixtures (13mm long and 3.75mm in diameter) & superstructure consisted of type IV gold alloy and resin Model 2- 3 wide diameter fixtures (13mm long and 5.0mm in diameter) & superstructure consisted of type IV gold alloy and resin Model 3-3 wide diameter fixtures (13mm long and 5.0mm in diameter) & superstructure consisted of titanium and resin Model 4-3 wide diameter fixtures (13mm long and 5.0mm in diameter) & superstructure consisted of titanium and porcelain A 150N occlusal force was applied on the 1st molar of each model in 3 directions - vertical($90^{\circ}$), horizontal($0^{\circ}$) and oblique($120^{\circ}$). After analyzing the stresses and displacements, following results were obtained. 1. There were no significant difference in stress distribution among experimental models. 2. Model 2, 3, 4 showed less amount of compressive stress than that of model 1. However, tensile stress was similar. 3. Veneer material with a high modulus of elasticity demonstrated less stress accumulation in the superstructure. Within the limites of this study, $Br{\aa}nemark\;Novum^{(R)}$ protocol demonstrated comparable biomechanical properties to conventional protocol.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.3
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• pp.56-64
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• 2021

Pavilion is an important landscape installation in the traditional landscaping and a representative facility that organizes space. To interpret and succeed the traditional landscape space, researches on the shape and structure of the traditional pavilion are also needed. However, researches on the style and structure of the traditional pavilion are difficult to be found. Accordingly this study aimed to identify the structural characteristics of roof part that occupied the largest portion in determining the shape of pavilion. Our research findings are as follows. As a result of analyzing 15 traditional Single-room square pavilions whose structure could be identified, it was found that the main building elements that distinguished the type of roof part in the Single-room square were crossbeam, ridge pole, and baluster. Depending on the presence of roofing members, pavilion was classified into five types: crossbeam, crossbeam+ridge pole, crossbeam+baluster, ridge pole, and baluster. In addition, as a result of analyzing the load and joint that worked on crossbeam based on the shape classification of roof part, it was found that in the traditional Single-room square pavilion, crossbeam was designed to play a balancing role between pillar and load. This study is significant in that it attempted to make a close interpretation of the shape of roof part in the pavilion and the role and function of building elements in terms of size, ratio, and load.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.21-32
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• 2022

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.