• Korean Journal of Childcare and Education
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• v.12 no.1
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• pp.57-81
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• 2016

The purpose of this study was to find out the feature of children's play according to a player number restriction rule in the free choice activities. And it is expected that the result of this study will contribute to improving the management of free choice activities. The participants of this study were a homeroom teacher, professor as a co-researcher and 25 4-year-old children of a private kindergarten. The data were collected by observation, children interview and reflective journal of the teacher from July to October in 2014. The results indicated that the children were stressed out with using name cards for presenting center selection, showed overcompetitive behaviors, and frequently violated the rules. The researchers found that the restriction rule had some dysfunctions, which were interferences of moral development, social-emotional development, self-regulation development, preventing safety-accident and free choice behavior. The researcher as a teacher abandoned the player number restriction rule, and observed the children's play. As a result, children's self-regulation abilities on physical space, play and conflicts improved and the teacher changed her strategy when managing free choice activities. Based on the results, the needs of various restriction rules and appropriate methods for applying the rules in free choice activities were further discussed.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.429-438
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• 2014

This study was designed to investigate the effects on anti-oxidative activities and increasing extraction yield of Aralia elata Cortex by gamma irradiation. Electron spin resonance (ESR) analysis as physical techniques for irradiation identification of Aralia elata showed that a pair of peak appeared on a space of 6.0 mT at the left and right of symmetric unspecific central ESR spectrums, confirming that the plant was gamma-irradiated. The optimum extracting conditions for preparing gamma irradiated samples from Aralia elata Cortex were to extract with 50% ethanol for 15 hrs after 10 kGy irradiation. DPPH scavenging activity and ABTS radical cation inhibitory activity of the water and 50% ethanol extracts from non irradiated and irradiated Aralia elata Cortex was very high as over 80% and 98%, respectively, at tested low concentration of $50{\mu}g/mL$. Antioxidant protection factor (PF) as anti-oxidation indicator of lipophilic compounds showed a very high level of activity as 2.18~2.78 PF. As for TBARs, water and ethanol extracts showed high level. Increase of TBARs inhibitory activity of water extracts was not shown by gamma-ray irradiation but ethanol extracts showed slight increasement of TBARs inhibitory activity with 10 kGy gamma-ray irradiation. These results shown confirmed increasement of extraction yield for phenolic compounds and anti-oxidative activity from Aralia elata. Thus, the treatment of gamma-irradiation can be used a way to amplify a solubility for biological active compounds and anti-oxidative activity in plants.

• Food Science and Preservation
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• v.12 no.2
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• pp.107-111
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• 2005

We investigated the quality of vaporized liquid of water-boiled pine needle in the aspects of drinking conformity and aroma characteristics. As a result, there was no hazardous component in the assessment for 45 types of ingredients. Especially, inorganic components such as arsenic (As), lead (Pb), mercury (Hg), and cadmium (Cd) which are harmful to human body were not detected. Additionally, we observed that other ingredients were present within the standard level suitable for drinking. The total 34 volatile components of the vaporized liquid of water-boiled pine needle were identified by dynamic head-space method. Fenchol, bomeol $\beta-fenchyl$ alcohol and bomyl acetate were the major volatiles and composed of 6.7, 13.1, 26.6 and $16.2\%$ of total volatiles, respectively. In addition, the alcohols and aldehydes were the prominent ingredients of which the contents showed comparatively high.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.607-613
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• 2006

For the reasonable use of low grade-shallow geothermal energy by Standing Column Well(SCW) system, the basic requirements are depth-wise increase of earth temperature like $2^{\circ}C$ per every 100m depth, sufficient amount of groundwater production being about 10 to 30% of the design flow rate of GSHP with good water quality and moderate temperature, and non-collapsing of borehole wall during reinjection of circulating water into the SCW. A closed loop type-vertical ground heat exchanger(GHEX) with $100{\sim}150m$ deep can supply geothermal energy of 2 to 3 RT but a SCW with $400{\sim}500m$ deep can provide $30{\sim}40RT$ being equivalent to 10 to 15 numbers of GHEX as well requires smaller space. Being considered as an alternative of vertical GHEX, many numbers of SCW have been widely constructed in whole country without any account for site specific hydrogeologic and geothermal characteristics. When those are designed and constructed under the base of insufficient knowledges of hydrgeothermal properties of the relevant specific site as our current situations, a bad reputation will be created and it will hamper a rational utilization of geothermal energy using SCW in the near future. This paper is prepared for providing a guideline of SCW design comportable to our hydrogeothermal system.

• Journal of Chest Surgery
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• v.45 no.3
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• pp.171-176
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• 2012

Background: Deep neck infections (DNI) can originate from infection in the potential spaces and fascial planes of the neck. DNI can be managed without surgery, but there are cases that need surgical treatment, especially in the case of mediastinal involvement. The aim of this study is to identify clinical features of DNI and analyze the predisposing factors for mediastinal extension. Materials and Methods: We reviewed medical records of 56 patients suffering from DNI who underwent cervical drainage only (CD group) and those who underwent cervical drainage combined with mediastinal drainage for descending necrotizing mediastinitis (MD group) from August 2003 to May 2009 and compared the clinical features of each group and the predisposing factors for mediastinal extension. Results: Forty-four out of the 56 patients underwent cervical drainage only (79%) and 12 patients needed both cervical and mediastinal drainage (21%). There were no differences between the two groups in gender (p=0.28), but the MD group was older than the CD group (CD group, $44.2{\pm}23.2$ years; MD group, $55.6{\pm}12.1$ years; p=0.03). The MD group had a higher rate of co-morbidity than the CD group (p=0.04). The CD group involved more than two spaces in 14 cases (32%) and retropharyngeal involvement in 12 cases (27%). The MD group involved more than two spaces in 11 cases (92%) and retropharyngeal involvement in 12 cases (100%). Organism identification took place in 28 cases (64%) of the CD group and 3 cases of (25%) the MD group (p=0.02). The mean hospital stay of the CD group was $21.5{\pm}15.9$ days and that of the MD group was $41.4{\pm}29.4$ days (p=0.04). Conclusion: The predisposing factors of mediastinal extension in DNI were older age, involvement of two or more spaces, especially including the retropharyngeal space, and more comorbidities. The MD group had a longer hospital stay, higher mortality, and more failure to identify causative organisms of causative organisms than the CD group.

• Journal of the Korea Computer Graphics Society
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• v.23 no.5
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• pp.39-49
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• 2017

In this study, we propose the core factors and application of asymmetric virtual reality(VR) content in which head-mounted display(HMD) user and Non-HMD users can work together in a co-located space that can lead to various experiences and high presence. The core of the proposed asymmetric VR content is that all users are immersed in VR and participate in new experiences by reflecting widely a range of users' participation and environments, regardless of whether or not users wear the HMD. For this purpose, this study defines the role relationships between HMD user and Non-HMD users, the viewpoints provided to users, and the speech communication structure available among users. Based on this, we verified the core factors through the process of producing assistive asymmetric VR content and cooperative asymmetric VR content directly. Finally, we conducted a survey to examine the users' presence and their experience of the proposed asymmetric VR content and to analyze the application method. As a result, it was confirmed that if the purpose of asymmetric VR content and core factors between the two types of users are clearly distinguished and defined, the independent experience presented by the VR content together with perceived presence can provide a satisfactory experience to all users.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.197-206
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• 2004

The ground anchor support system may not be occasionally used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then could play important roles to reduce deformations mainly in the upper part of the nailed-soil excavation system as well as to improve local stability. In this study, a newly modified soil nailing technology named as the PSN (Pretension Soil Nailing), is developed to reduce both facing displacements and ground surface settlements in top-down excavation process as well as to increase the global stability. Up to now, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the PSN system. Also, proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear, Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretension of the soil nails are examined in detail throughout an illustrative example and the $FLAC^{2D}$ program analysis. And a numerical approach is proposed PSN system using the shear strength reduction technique with the $FLAC^{2D}$ program.

• Journal of Radiation Protection and Research
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• v.20 no.4
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• pp.237-243
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• 1995

An estimate is made on the potential generation rate of H: from radiolysis of the Paraffin-wax encapsulant Proposed for the solidified liquid concentrate wasteform. The results show that the radiolytic Production of $H_2$ from paraffin-wax-encapsulated waste is dominated by the radiation energy released from $^{60}Co$. The radiolytic production of $H_2$ will proceed at an initial rate equivalent to aproximately $4.4{\times}10^2cm^3yr^1$ in 200 litre drums that are partly filled with 120 litres of encapsulated waste. The gas production rate will fall to a value of $7.2cm^3yr^1$ after 100 years. The lower flammable limit for $H_2$ in air will be reached in about 25 years and the lower explosive limit for $H_2$ in air would not be reached in 1000years. The timescale in which these safety-related limits are reached is strongly dependent on the level of filling of each waste drum. A reduction of the air space inside each drum would reduce the time required to reach the lower flammable limit.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.35-46
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• 2012

This study attempts to specifically analyze green volume and scenery characteristics by classifying the streets in Seoul and suggest improvements accordingly. The subject streets for research were limited to those that have high occupancy ratio and are wide enough to have a big potential in improving green volume. In terms of green volume and scenery according to the types of streets, Platanus occidentalis and Ginkgo biloba were most common regardless of the street type, and the green ratio was 51.6% in residential areas, 50.4% in commercial areas, and 43.7% in business areas. Apart from the residential area, there was almost no green areas, and the ratio of green coverage was 71.0% in business areas, 64.0% in green areas, 37.3% in residential areas, and 36.2% in commercial areas, while the green volume coefficient was $1.9m^3/m^2$ on average. Based on the study results, it was set as a goal to provide the residential areas with a green community space and flowering trees throughout the year for scenery, and commercial areas with flowering trees and maples to emphasize the stores' image while not interfering with service and walking. For business areas, the goals were to improve green ratio and create streets that suit the urban image, and to set up spaces to provide habitat for wild animals with multi-layer planting and link to surrounding forests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.269-278
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• 2018

In Korea, BIM technology is applied mainly to building construction projects, but is expected to be applied rapidly to civil engineering projects because the government is currently considering the mandatory application of BIM for infrastructure facilities. Because the infrastructure project is processed in a horizontal work area, the application of BIM technology is more useful in the schedule management of the construction phase than the interference management of the design phase. The 4D CAD system is a typical BIM technology applied to the schedule management in the construction phase, but the application to the actual project is limited due to the lack of practical functions. This study examined the functions of four representative 4D CAD systems commercialized so that the selection criterion can be provided according to the characteristics of the project, and suggests that the functions that should be improved to have practicability. As a result of functional analysis, the application characteristics of each system were analyzed and the user convenience was suggested. In addition, a linear 4D simulation methodology was developed to improve the functions applicable to civil engineering projects, and ways to improve the utilization of the infrastructure projects as the construction phase BIM were suggested. In railway and road construction projects, most activities, such as earthwork, bridges, and tunnels proceed along the distance axis in a horizontal space. Therefore, a linear 4D simulation method, in which an activity is expressed along a distance axis, can be more practically useful rather than a simple 4D simulation method with a Gantt chart.