• Journal of Naturopathy
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• v.9 no.1
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• pp.27-32
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• 2020

Purpose: The purpose of this study was to investigate the changes in the autonomic nervous system of the human body after the use of ocher bedding radiating far-infrared rays to 15 insomnia subjects. Methods: Changes of autonomous nerve in the subjects after using loess bedding estimated by heart rate variability. Results: The mean HF before the use of ocher bedding was 220.8 msec², and the mean after use decreased to 5.1 msec². The average value of LF before use was 418.1 msec², and the mean after use decreased to 5.2 msec². The average before use of the VLF was 1463.3 msec², and the average after use dropped to 6.8 msec². The average value of TP before use was 977.3 msec², and the average after use dropped to 6.7 msec². The decrease in postoperative values of all four items was statistically significant, and the high value of the subjects before use inferred to be the reason that all of the subjects had high stress and anxiety due to their long-term sleep disorder. There was no significant difference in the pulses of the subjects before the use of the bedding. SDNN and RMSSD were not significantly different before and after use. Conclusions: Autonomic nerves HF, LF, VLF, TP frequency is evaluated to be affected by the investigation of far-infrared radiation that occurs ocher. This research data regarded as high value as primary data in this field.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.57-65
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• 2022

This study investigated the electromechanical response of smart ultra-high performance fiber reinforced concretes (S-UHPFRCs) under flexural loading to evaluate the self-sensing capacity of S-UHPFRCs in both tension and compression region. The electrical resistivity of S-UHPFRCs under flexural continuously changed even after first cracking due to the deflection-hardening behavior of S-UHPFRCs with the appearance of multiple microcracks. As the equivalent bending stress increased, the electrical resistivity of S-UHPFRCs decreased from 976.57 to 514.05 kΩ(47.0%) as the equivalent bending stress increased in compression region, and that did from 979.61 to 682.28 kΩ(30.4%) in tension region. The stress sensitivity coefficient of S-UHPFRCs in compression and tension region was 1.709 and 1.098 %/MPa, respectively. And, the deflection sensitivity coefficient of S-UHPFRCs in compression region(30.06 %/mm) was higher than that in tension region(19.72 %/mm). The initial deflection sensing capacity of S-UHPFRCs was almost 50% of each deflection sensitivity coefficient, and it was confirmed that it has an excellent sensing capacity for the initial deflection. Although both stress- and deflection-sensing capacity of S-UHPFRCs under flexural were higher in compression region than in tension region, S-UHPFRCs are sufficient as a self-sensing material to be applied to the construction field.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.413-421
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• 2022

This study was conducted to identify the vegetation structure of the Abies nephrolepis forests by analyzing species composition in Mt. Doota and Mt. Cheongok in the Gangwon region with the phytosociological method. In order to perform a field investigation, 18 survey areas with an area of about 400 m2 were set up for the stands where A. nephrolepis grow wild. Communities were classified through TWINSPAN and visualized using DCA (Detrended Correspondence Analysis). Species diversity analysis, importance value analysis, and DBH class analysis were employed to identify the characteristics of each community. As a result, the A. nephrolepis forests in Mt. Doota and Mt. Cheongok have been classified into 4 communities; GroupI, II, III and IV. GroupIis Quercus mongolica-A. nephrolepis competitive forest dominated by Q. mongolica and A. nephrolepis in the order. Group II is A. nephrolepis-Betula ermanii competitive forest dominated by A. nephrolepis, Sorbus commixta, and B. ermanii in the order. Group III is dominated by A. nephrolepis, but is expected to have competition between A. nephrolepis and Q. mongolica in the future due to the mass occurrence of Q. mongolica saplings. A. nephrolepis, S. commixta, and Q. mongolica are the dominant species in Group IV, and A. nephrolepis is the major dominant species in all layers. The species diversity of the A. nephrolepis forests in Mt. Doota and Mt. Cheongok is lower than other A. nephrolepis forests in Mt. Seorak, Maruguem, and Mt. Odae. It is necessary to establish conservation measures and to continuously monitor the A. nephrolepis forests in Mt. Doota and Mt. Cheongokis due to the harsh environment and the competition that may occur between A. nephrolepis and deciduous trees such as Q. mongolica in the future.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.299-309
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• 2022

YouTube videos secure the latest trends in the field and provide viewers' preferences and non-preferences. This study analyzes the discussion of death in recent YouTube videos and explores the relationship between life, well-dying, and well-aging. The purpose of this study is to contribute to the establishment of a healthy life for Koreans by exploring relevance. The survey period and target are 13 videos uploaded on YouTube from 2019 to 2021. As a result of the investigation, it was possible to encompass 25 speakers who were discussing death centered on doctors. Video speakers in charge of various areas conducted various discussions on death from the perspective of experts. The key points are the true value of life, death that you don't need to fear, the importance of hope, the naturalness of death, etc. 11 expert perspectives are measured into 4 types based on 4 criteria: life, death, well-aging, and well-dying. Despite the limitations of studying 13 extracted at a specific time, this study revealed that YouTube videos are a place for free communication. It can contribute in part to maintaining and improving the health of our lives in the future and researching convergence.

• Advances in nano research
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• v.13 no.6
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• pp.575-585
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• 2022

Due to its biofilm formation and colonization of the osteocyte-lacuno canalicular network (OLCN), Staphylococcus aureus (S.aureus) implant-associated bone infection (SIABI) is difficult to cure thoroughly, and may occur recurrently subsequently after a long period dormant. It is essential to explore an alternative therapeutic strategy that can eradicate the pathogens in the infected foci. To address this, the polymethylmethacrylate (PMMA) bone cement and Fe3O4 nanoparticles compound cylinder were developed as implants based on their size and mechanical properties for the alternative magnetic field (AMF) induced thermal ablation, The PMMA mixed with optimized 2% Fe₃O₄ nanoparticles showed an excellent antibacterial efficacy in vitro. It was evaluated by the CFU, CT scan and histopathological staining on a rabbit 1-stage transtibial screw model. The results showed that on week 7, the CFU of infected soft tissue and implants, and the white blood cells (WBCs) of the PMMA+2% Fe₃O₄+AMF group decreased significantly from their controls (p<0.05). PMMA+2% Fe₃O₄+AMF group did not observe bone resorption, periosteal reaction, and infectious reactive bone formation by CT images. Further histopathological H&E and Gram Staining confirmed there was no obvious inflammatory cell infiltration, neither pathogens residue nor noticeably burn damage around the infected screw channel in the PMMA+2% Fe₃O₄+AMF group. Further investigation of nanoparticle distributions in bone marrow medullary and vital organs of heart, liver, spleen, lung, and kidney. There were no significantly extra Fe₃O₄ nanoparticles were observed in the medullary cavity and all vital organs either. In the current study, PMMA+2% Fe₃O₄+AMF shows promising therapeutic potential for SIABI by providing excellent mechanical support, and promising efficacy of eradicating the residual pathogenic bacteria in bone infected lesions.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.435-450
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• 2022

In step-by-step site selection for geological disposal of high-level radioactive waste, parameters necessary for site selection will be acquired through deep drilling surveys from the basic survey stage. Unlike site investigations of rock mass structures such as tunnels and underground oil storage facilities, those related to the geological disposal of high-level radioactive waste are not only conducted in relatively deep depths, but also require a high level of quality control. In this report, based on the 750 m depth drilling experience conducted to acquire the parameters necessary for deep geological disposal, the methodology for deep drilling and the geology, geophysics, geochemistry, hydrogeology and rock mechanics obtained before, during, and after deep drilling are discussed. The procedures for multidisciplinary geoscientific investigations were briefly described. Regarding in-situ stress, one of the key evaluation parameter in the field of rock engineering, foreign and domestic cases related to the geological disposal of high-level radioactive waste were presented, and variations with depth were presented, and matters to be considered or agonized in acquiring evaluation parameters were mentioned.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.530-548
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• 2022

The site selection process for deep geological disposal of high-level radioactive waste will be conducted in stages, and 103 evaluation parameters related to site selection have been proposed. In the field of rock mechanics and rock engineering, there are 33 evaluation parameters for intact rock, joint and rock mass, and they are applied in the basic and detailed investigation stages. In this report, uniaxial compressive strength, in-situ stress, joint distribution, and rock mass classification were selected as the main evaluation parameters, and among them, uniaxial compressive strength and in situ stress were selected as key evaluation parameters. Statistical techniques or regression analysis were performed for granite in Wonju and Chuncheon to evaluate the distribution range for the selected key evaluation parameters. The average of the uniaxial compressive strength in the Wonju area estimated through the posterior distribution is about 171 MPa, and about 123 MPa in the Chuncheon area. The maximum in situ stress acting in the Wonju area was less than 30 MPa and less than 40 MPa in the Chuncheon area. The direction of the maximum horizontal stress calculated by regression analysis was 101° in Wonju, and in the case of Chuncheon, it was 95°, respectiviely.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.23-32
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• 2022

Although PSCB girder bridges account for 4% of the bridges in use on highways, they do not account for much, but 98% of PSCB girder bridges are 1^st type and 2^nd type of bridge. Also, the total length of the PSCB girder bridge is 16% (192km) of the total length of the highway bridge. Thus, the PSCB girder bridge can be one of the bridge types where maintenance is important. In order to analyze the damage types of PSCB girder bridges, a detailed analysis was conducted by selecting 62 places (477 spans) precision safety diagnosis reports considering ratio of the construction method and snow removal environment exposure class. Analysis of report and a field investigation was conducted, and as a result, most of the causes of deterioration damage were caused by rainwater (salt water) flowing into the bridge pavement soaking in between the top flange and the interface. After concrete slab deteriorate occurred then bridge pavement cracking and breaking increased and exfoliation of concrete occurred by corrosion and expansion of the reinforcing bars occurred. In addition, the cause of cracks in the longitudinal direction on the bottom of the top flange is considered to be cracks caused by restrained drying shrinkage. In conclusion, for reasonable maintenance considering the characteristics of PSCB girder bridges, it should be suggested in the design aspect that restrained drying shrinkage crack on top flange. Also, it is believed that differentiated maintenance method should be proposed according to snow removal environment exposure class.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.391-396
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• 2021

In this study, items for forest policy and forest resource research in Austria, Japan, New Zealand, and Indonesia, which are major forest advanced countries, were investigated, and the applicability of point cloud data acquired through laser scanning was identified. Through the study, it was found that forest policies in developed countries are being pursued for the purpose of sustainable forest conservation and management, job creation, and timber productivity improvement, and that new technologies are being researched and applied to actual projects. Korea has a high proportion of forests compared to the national land area compared to major forestry developed countries, but the accumulation of trees is relatively low, so it is a time for scientific forest management to improve the accumulation of trees. To understand the applicability of laser scanning technology, a forest resource survey using point cloud data was conducted, and the diameter of breast height, height, number of trees per unit area were calculated, and the shape of the crown was identified. If field experiments and accuracy evaluations applying various laser scanning technologies are carried out in the future, it will be possible to present the quantitative improvement of forest resource survey using foil cloud.

• Journal of Korean Elementary Science Education
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• v.40 no.4
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• pp.460-479
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• 2021

The crisis of the COVID-19 pandemic has caused significant changes in education systems worldwide, including in Korea. Due to COVID-19's social distancing policies, the education system was suddenly switched to distance learning, resulting in many problems in primary schools without preparation. The purpose of this study was to investigate a teacher's awareness of science education techniques, responses to issues in science classes, including inquiry activities, advantages and disadvantages, and roles after experiencing distance learning. Survey and focus interviews were conducted for primary school teachers who had previously participated in distance learning, such as online content classes and real-time interactive classes. The study findings showed three conclusions: 1) Primary school teachers conducted one-way and interactive lectures in online classes. It is vital to improve a teacher's digital literacy to improve other teaching methods such as investigation and discussion in online classes. 2) Primary school teachers acknowledged the challenges of field feedback, inquiry item preparations, and safety in inquiry activities of science classes, by providing individual experimental packages and videos and using online discussion and feedback among teacher - student and student - student interactions. 3) Primary school teachers recognized that various types of classes using IT devices and individualized learning were possible as advantages of distance learning. As for disadvantages, it was acknowledged that inquiry activities, cooperative learning, immediate feedback, and interaction among students were challenging. Furthermore, learning gaps were wider in distance learning.