• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.252-258
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• 2018

A larger energy consumption and concentration of population induced green house gas glowing and heat island effect in the urban space. Roof green system was a effect method to reduce green house gas and heat concentration in the city. Therefore, construction of this system was increasing. Most of lightweight soil used in roof green system was perlite, but this caused dust and skin disease. So it needed to develop another new lightweight soli for roof green system. Meanwhile, a thermoelectric power plant generated bottom ash as a by-product. According to previous research, bottom ash could be used for artificial lightweight soil with 60 wt% of mixing rate. But this study was proceed to develop a artificial lightweight soil using bottom ash with higher mixing rate by 65 wt% and different organic ingredients. First, physical and chemical properties of bottom ash was investigated. Then test according to landscaping design standard was proceeded for various artificial lightweight soil mix types using bottom ash, bark, compost and coco peat. As a result, the artificial lightweight soil with 65% of bottom ash, 30% of bark and 5% of compost was suitable for low and middle range of soil standard.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.2
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• pp.136-143
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• 2013

In the sewage structures and wastewater facilities, concrete is exposed to hydrogen sulfide ($H_2S$) which acts as an acid material in a solution, and a strongly acidic sulfate ion ($SO{_4}^{-2}$) is generated by a sulfuric bacteria. Hence, a degradation of concrete with biochemical corrosion would be accelerated. Finally, durability of concrete and concrete structures may be greatly reduced. In this study, in order to remove the hydrogen sulfide which is used by the sulfuric bacteria organic-biologically, the antibiotic metal and metallic salt powders were mixed to concrete, and a suppressing performance of the sulfate ion was assessed. For the sulfuric acid bacteria, a comparative evaluation of antimicrobial performance on neutralized concrete specimens were carried out, also by a rapid chloride penetration test, chloride penetration depths and diffusion coefficients were measured for antibiotic concrete in accordance with the amount of metal and metallic salt-based antibacterial agents. Eventually, by an observation of the biochemical state of the surface of concrete specimens exposed outdoors, the performance and applicability of antibiotic concrete were confirmed.

• Child Health Nursing Research
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• v.20 no.3
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• pp.149-158
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• 2014

Purpose: The purpose of this study was to investigate caregivers' knowledge, concerns, and management of children with febrile convulsions (FC). Methods: A descriptive correlation study was conducted with 133 caregivers whose children had been diagnosed with a FC. A self-administered questionnaire was used for data collection A self-administered questionnaire was used for data collection. Descriptive statistics, t-test, one-way analysis of variance and Pearson's correlation were used for data analysis. Results: The mean percent of correct answers related to knowledge was 48.5%. Many caregivers believed that FC causes brain damage and did not know that risk of subsequent epilepsy in FC is rare. Levels of concern about FC were high. Caregivers were highly concerned about further FC attacks in the night and tended to worry that Febrile children were apt to get a fever. Many caregivers used management practices which are not recommended for FC in children. There was a statistically significant negative correlation between caregivers' knowledge and concerns about FC. There was also a positive correlation between caregivers' knowledge and management of FC. Conclusion: Findings suggest that improvements are needed in caregivers' knowledge and management of FC. Caregivers' concerns related to misconception need to be addressed. Development and evaluation of educational interventions on changing caregivers' management of FC are recommended.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.17-27
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• 2014

Numerical model became one of most important tools for identifying the state of an existing structure in accordance with development of numerical analysis techniques. A numerical model should be updated based on the measured responses from the existing structure to accurately use the model for identifying the state of the bridge and executing numerical experiments. In this study, a new model updating method based on repetition method without a differential function is introduced and applicability for high speed railway bridge is verified with dynamic stability analysis. A fine measurement based on measurement points roaming method was executed with an wireless measurement system for precise dynamic characteristic analysis. The natural frequencies and mode shapes were estimated by correlation analysis and a mode decomposition technique. An initial numerical model was constructed based on design drawings and the model have been updated in accordance with the introduced model updating method. The results from numerical experiment and field test have been compared for verifying the applicability of the model updating method. And the dynamic stability analysis has been executed to verify the usability of the updated numerical model and the model updating method. It seems that the model updating method can be used for various bridges after evaluation of applicability for other type bridges in further studies.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.3
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• pp.21-28
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• 2022

Fine dust enters the lungs or blood vessels through the respiratory tract through the air. Recently, due to the fine dust problem, the demand for air purifiers in Korea is also increasing rapidly. Moss is the oldest terrestrial plant, and it is known that it has the property of adsorbing and decomposing heavy metals and fine dust. To compare the effect of reducing fine dust between moss and the existing chemical filter (Hepa), a cube of 1 m³ was manufactured and the amount of fine dust reduction under a controlled environment was compared. Under the fine dust conditions, an umbrella moss filter, rat tail moss filter, feather moss filter, and silk moss filter were inserted for a total of 40 experiments, 10 times each in 4 different situations. The difference between the amount after 30 minutes was statistically significant for all filters. However, as a result of the test, it was confirmed that there was no statistically significant difference between filters for fine dust, mixed gas, CO₂, and O₂. In particular, it was confirmed that the previously claimed effect of oxygen generation was almost nonexistent. Through this result, it was confirmed that the reduction of fine dust is effective regardless of the species view of moss, and it is expected to replace or supplement the chemical filter of the existing air purifier through future improvement.

• Archives of design research
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• v.20 no.3 s.71
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• pp.129-140
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• 2007

This study attempts to investigate the personalized schemes of interface for the interactive TV sonics enhancing the satisfaction of users from the standpoints of the user and to suggest designing guidelines. In the preface, firstly, the purpose as well as structure of the study were described, the characteristics of the interactive TV and the personalization were defined. Also, it was attempted to understand the development directions of the basic media for services. In addition, the data and elements that became the ground for this study were arranged, including the elements for designing interface, the appraisal method of usability to evaluate the requirements of users, etc. Then, the interfaces of "SkyTouch", an interactive TV sonics by Skylife having the number of users reaching one million at the moment, that is the representative runner in the interactive TV, were analyzed. Then the needs central to the navigation structure and layout for the convenience of users through the evaluation of usability were examined and arranged. In addition, the designing directions of personalized interfaces were studied in the interactive TV by analyzing the web portal sites which were being carried out prior to the personalized services. Based on the data investigated and analyzed previously, the guidelines for the interface design for the personalization of the interactive TV were suggested by classifying the navigation structure and layout, and the personalized interface design was proposed according to the suggested guidelines by applying them directly to "SkyTouch" that is currently carrying out the interactive sonics although it provides limited services in an independent style.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.550-560
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• 2018

Many countries have provided support for research and development and implemented policies for Advanced Driver Assistance Systems (ADAS) for enhancing the safety of vehicles. With such efforts, the toll of casualties due to traffic accidents has decreased gradually. Korea has exhibited the lowest toll of casualties due to traffic accidents and is ranked 32nd in mortality among the 35 OECD members. Traffic accidents typically fall into three categories depending on the cause of the accident: vehicle to vehicle (V2V), vehicle to pedestrian (V2P), and vehicle independent. Most accidents are caused by drivers' mistakes in recognition, judgment, or operation. ADAS has been proposed to prevent and reduce accidents from such human errors. Moreover, the global automobile industry has recently been developing various safety measures, but on-road tests are still limited and contain various risks. Therefore, this study investigated the international standards for evaluation tests with regard to the assessment techniques in braking capability to cope with the limitations of on-road tests. A theoretical formula for braking force and a control algorithm are proposed, which were validated by comparing the results with those from an on-road test. These results verified the braking force depending on the functions of ADAS. The risks of on-road tests can be reduced because the proposed theoretical formula allows a prediction of the tendencies.

• Korean Security Journal
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• no.39
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• pp.95-130
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• 2014

The purpose of this study focuses on developing the outplacement competency of special security government official for which precedent reference research, expert review, and expert Delphi analysis used according to three steps of study process. The final Delphi examination analysis resulted in outplacement competency into four groups of competency and twenty-two subcategories. Thus, it is very worthy to develop outplacement's competencies necessary for outplacement of special security government official through expert's Delphi examination in the first time, which have not being researched until now, and to present them theoretically through clarification and verification process accomplished by experts and staffs related to outplacement. Individual effort is essential to strengthen their capabilities based on accurate self evaluation, for which the awareness and concept need to be redefined to help them face up to the reality by readjusting career goal to a realistic level. Also, active career development plan to improve shortcoming in terms of outplacement competency is required. The result of this study, which ouplacement successors of special security government officials participated studying process, will be used as the basic data to establish an outplacement curriculum and an educational system for strengthening competency necessary for outplacement of special security government official.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6A
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• pp.417-424
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• 2011

This study focused on development of 60 m span PSC girder considering not only structural performance, but also economical efficiency and constructability including from the improvement of cross-section to the tendon profiles in sequence. Bulb-T type cross section was derived from optimization and actual possibilities to design a bridge were assessed through cross section evaluation. Tendons were also arranged efficiently so that the girder could resist the service load effectively. After developed girder was applied to a sample bridge, result of finite element analysis proved all load steps were satisfied with the allowable stress. Furthermore, it seemed that sufficient redundancy will be available to design a bridge safely. Based on these, a full-scale 60 m span girder was fabricated and 4 point bending test was performed. An initial crack occurred over twice of the service load in this experiment, which establishes adequate structural performance. 60 m span Half-Decked PSC girder developed in this study has a lower height for the given span which resulted from cross section improvement and efficient tendon layout. This girder also has not only the structural advantage, but also advantages in economical efficiency and constructability.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.433-439
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• 2023

In this study, the bonding performance of repair materials was evaluated on concrete repair surface to develop concrete repair materials based on UHPC (Ultra High Performance Concrete) which has high mechanical and durability performance. The ten test variables were applied considering the roughness and wet condition of the concrete surface subject to repair, the addition of polymer, and the use PP and PVA fibers in repair materials. The addition of the polymer caused a significant decrease in strength, which was thought to be due to the effect of the additional super plasticizer used to adjust workability. Also, flow was reduced by up to 13.8 % with the use of plastic-based fibers. As a result of evaluating the bond strength of the repair material considering the condition of the surface subject to repair, it was thought that in the case of using UHPC-based repair material, high bonding performance could be secured without any additional surface treatment as long as the surface of the base material was sound. In addition, UHPC-based repair materials showed high bonding performance even when the attachment surface was wet. In the future, research will be conducted on shot-crete application and gradient pouring for the development of UHPC-based repair materials, and continuous improvement in the repair material mixing property will be carried out to ensure economic efficiency and performance as a concrete structural repair material.