• Journal of the Korea Institute of Building Construction
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• v.24 no.1
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• pp.55-66
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• 2024

This research addresses the types and causes of defects in seismic retrofitting projects of school facilities, which, following the Gyeongju and Pohang earthquakes in September 2016 and November 2017 respectively, have been identified as having comparatively lower seismic resilience among public buildings. The incidence of seismic retrofitting has notably increased in the subsequent years, raising concerns about the potential for defects arising from these efforts. The government has committed to enhancing the seismic resilience of all public facilities by 2035, with a specific focus on completing upgrades for educational establishments by 2029. Although prior investigations have explored construction defects in school facilities, there exists a gap in research specifically targeting defects within seismic retrofitting processes. Thus, this study aims to catalog the defects associated with seismic retrofitting efforts and analyze their underlying causes to identify crucial management strategies for defect mitigation. Furthermore, by examining the interplay between defect types and their causative factors, the study seeks to pinpoint essential management practices that could preempt defects during the construction phase, ultimately aiding in the reduction of future maintenance expenditures.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.191-208
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• 2024

In this study, a hydro-mechanical-damage coupled analysis model was developed to evaluate the structural safety of radioactive waste disposal structures. The Mazars damage model, widely used to model the fracture behavior of brittle materials such as rocks or concrete, was coupled with conventional hydro-mechanical analysis and the developed model was verified via theoretical solutions from literature. To derive the numerical input values for damage-coupled analysis, uniaxial compressive strength and Brazilian tensile strength tests were performed on concrete samples made using the mix ratio of the disposal concrete silo cured under dry and saturated conditions. The input factors derived from the laboratory-scale experiments were applied to a two-dimensional finite element model of the concrete silos at the Wolseong Nuclear Environmental Management Center in Gyeongju and numerical analysis was conducted to analyze the effects of damage consideration, analysis technique, and waste loading conditions. The hydro-mechanical-damage coupled model developed in this study will be applied to the long-term behavior and stability analysis of deep geological repositories for high-level radioactive waste disposal.

• Journal of Space Technology and Applications
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• v.3 no.4
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• pp.333-341
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• 2023

This study aims to develop technology for testing and verifying the space radiation environment of miniature space components using the facilities of the domestic 100 MeV proton accelerator and the Space Component Test Facility at the Space Testing Center. As advancements in space development progress, high-performance satellites increasingly rely on densely integrated circuits, particularly in core components components like memory. The application of semiconductor components in essential devices such as solar panels, optical sensors, and opto-electronics is also on the rise. To apply these technologies in space, it is imperative to undergo space environment testing, with the most critical aspect being the evaluation and testing of space components in high-energy radiation environments. Therefore, the Space Testing Center at the Korea testing laboratory has developed a radiation testing device for memory components and conducted radiation impact assessment tests using it. The investigation was carried out using 100 MeV protons at a low flux level achievable at the Gyeongju Proton Accelerator. Through these tests, single event upsets observed in memory semiconductor components were confirmed.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.31.1-31.10
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• 2023

Background: With modernization, air pollution has become increasingly serious, and its effects on health have been revealed. As a result, public interest in environmental pollution has become critical for regulating air pollution. In our study, we aim to evaluate the impact of air pollution levels on public attention to environmental issues and examine whether awareness of the residential environment's impact on health acts as a mediator in this relationship. Methods: We conducted an analysis on 400 individuals surveyed in the preliminary feasibility study on adverse health effects in the Pohang Industrial Complex, to examine the relationship between particulate matter 2.5 (PM2.5) and attention to environmental issues. Logistic regression analysis was performed, and mediation analysis was used to determine whether awareness of the residential environment's impact on health mediated the relationship. Results: The logistic regression analysis results showed that PM2.5 levels were associated with attention to environmental issues (adjusted odds ratio [AOR]: 2.1; 95% confidence interval [CI]: 1.3-3.5; p = 0.003) and awareness of health impacts (AOR: 3.4; 95% CI: 1.6-7.1; p = 0.001). The PM2.5 levels showed 9.9% (95% CI: 5.4-14.0) increase in the prevalence of high attention to environmental issues, of which, only 1.0% (95% CI: 0.2-2.3) were mediated by health impact awareness. In the overall analysis, 10% of the total effect of PM2.5 on attention to environmental issues was mediated by health impact awareness. Conclusions: According to this study's results, there was a correlation between air pollution levels and attention to environmental issues. Awareness of the health impacts of air pollution partially mediated the effect of air pollution levels on attention to environmental issues. In future studies, it is recommended to identify other mediators to further understand this structure.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.4
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• pp.48-59
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• 2014

This study was carried out to present raw data on managing the restored urban stream by studying the naturalized plants distributed in Gaeumjeong Stream, Changwon-si, Gyeongsangnam-do, Korea. The results were as follows. The numbers of naturalized plants were summarized as 45 taxa including 17 families, 36 genera, 43 species and 2 varieties. The invasive alien plants were 2 taxa including Ambrosia artemisiifolia and Lactuca sativa. The following summarizes the attributes of the naturalized plants. Most of the plants commonly originated from Europe and North America. The 5 naturalized degree that was widely distributed and had many individual was the most common. Until 1921, after the opening of 1 period was the most common in the introduced period. Section 12 had the highest NI at 41.9%, and the lowest, at 20.5%, in sections 9 and 19 were analyzed. Section 1 had the highest UI at 6.2%, whereas, the lowest, at 2.5%, was calculated in sections 19 and 20. Section 2 showed the highest DI at 16.7%. The first results of the analysis of the causes for the invasion of naturalized plants on the riverside and waterways, and physical factors and maintenance are directly affected. Second, sewage, muddy water and sediment deposits this naturalized plant caused by a chemical factor. Third, it is thought that invasive alien plants are irregular as it happens in biological factor. The proposed management plan naturalized plants, the first, disturbance caused by species management is a young object is removed immediately before flowering scape to eliminate or suppress the propagation of physical methods will be needed. Second, the fact that the national spread of native plant species and planting management does not provide space for the growth is very important. Third, agricultural land is disturbed by agricultural practices by interfering with the action of naturalized plants because the source of the river should be prohibited in agriculture. In the future, if we studied the naturalized plants distributed in restored streams located in Changwon-si, the characteristics of change in the ecosystem impact is expected to be beneficial.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.3
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• pp.147-153
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• 2013

There exist various types of the WEC (Wave Energy Converter), and among them, the point absorber is the most popularly investigated type. However, it is difficult to find examples of systematically measured data analysis for the design of the point absorber type of power buoy in the world. The study investigates the wave load acting on the point absorber type resonance power buoy wave energy extraction system proposed by Kweon et al. (2010). This study analyzes the time series spectra with respect to the three-year wave data (2002.05.01~2005.03.29) measured using the pressure type wave gage at the seaside of north breakwater of Hupo harbor located in the east coast of the Korean peninsula. From the analysis results, it could be deduced that monthly wave period and wave height variations were apparent and that monthly wave powers were unevenly distributed annually. The average wave steepness of the usual wave was 0.01, lower than that of the wind wave range of 0.02-0.04. The mode of the average wave period has the value of 5.31 sec, while mode of the wave height of the applicable period has the value of 0.29 m. The occurrence probability of the peak period is a bi-modal type, with a mode value between 4.47 sec and 6.78 sec. The design wave period can be selected from the above four values of 0.01, 5.31, 4.47, 6.78. About 95% of measured wave heights are below 1 m. Through this study, it was found that a resonance power buoy system is necessary in coastal areas with low wave energy and that the optimal design for overcoming the uneven monthly distribution of wave power is a major task in the development of a WEF (Wave Energy Farm). Finding it impossible to express the average spectrum of the usual wave in terms of the standard spectrum equation, this study proposes a new spectrum equation with three parameters, with which basic data for the prediction of the power production using wave power buoy and the fatigue analysis of the system can be given.

• Korean Security Journal
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• no.40
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• pp.209-242
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• 2014

This study is to understand sure the primary crime prevention has been incidence as a social problem intended for parents through the analysis of the Crime Prevention Design (CPTED) CPTED element of recognize elements that target crime prevention strategy to effectively help students be and an object of the present invention is to provide a policy suggestion haryeoneunde proposed basic data required for orientation. To achieve the study objectives such as the core framework in this study IPA: Importance-Performance Analysis) also was selected. Subjects of study in 2010 Gyeongju Elementary parents name and were 203 first research group investigating the secondary school population of the region in 2014 to nomadic parents of 297 people sampled selection. Questionnaire that use by this study applies "Important-Performance Analysis : IPA" technique that Martilla & James(1977) presented and analyzed awareness for CPTED elements of strategy for student's crime prevention to elementary school pupil students' parentse. It was the first group, 0.886, 0.920, 0.895 and 2nd group 0.880, 0.906, 0.878 that reliability of (Cronbach' s ${\alpha}$) the importance, and believability of run chart was the first group, 0.880, 0.917, 0.878 and 2nd group, 0.735, 0.840, 0.830. Analysis of the data carried out frequency analysis, reliability analysis, Frequency analysis was performed, paired sample t-Test for the reliability analysis, and the technical statistical analysis of the data is. The analysis of lattice bars execution through the IPA, the importance of the primary parents elements of CPTED strategies are generally very high, but found that the variation depending on the components that Performance. This study, an important element of the strategy to eliminate the school building for students from inside and outside the criminal fears CPTED is a mechanical surveillance in the first group, organizational surveillance, and the second group is the region intensified I'll showed mechanically and organizational factors in the investigation, and request that the investment is urgently important element is also execution low, crime prevention personnel security higher importance than expanding the front door. The analysis result of this study expects that basic data can be used in policy direction presentation that examines closely CPTED elements of strategy for crime prevention of students and applies CPTED's component effectively at elementary school hereafter.

• Journal of agricultural medicine and community health
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• v.43 no.1
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• pp.9-17
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• 2018

Objectives: This study was to assess the status and awareness of excessive heat exposure among agricultural workers. Methods: We selected a total of 90 farmers from a villages of Gyeongju-si, during August, 2015. We carried out the temperature measurement for nine times and derived Health Index (HI) and Wet Bulb Globe Temperature (WBGT) index. We compared the HI, WBGT and excessive heat warnings. Status of high temperature exposure, lifestyle, medical history, and awareness about excessive health related exposure illness assessed using survey questionnaires. Results: The matching rates between the WBGT and the HI during excessive heat warning were high, but when it was a non-excessive heat warning, there were days of excessive HI or WBGT. Out of 90 farmers surveyed, 78 cases (86.7%) were in their 60s and older age group. Slightly more than two third (71.1%) farmers were farming in the dawn-morning (71.1%), and the daily working hours were less than 4 hours (54.4 %), but only 23.3% among farmers took regular breaks. Of total, 14.4% farmers experienced excessive heat exposure related illness in order of tiredness, lethargy, dizziness, headaches, and sweating. Overall, the awareness of the danger for excessive heat and the heat wave warnings were high at 70.0% and 74.4%, respectively. Conclusions: Politically, the excessive heat warnings should not be taken into account the simple temperature measurement but, have to consider WBGT and HI standards at the same time. Farmers need to be promoted and educated to prevent the excessive heat related illness by periodically increasing their rest time during farming.

• Journal of Embryo Transfer
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• v.30 no.2
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• pp.73-82
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• 2015

This study was designed to evaluate the possibility of increase through dairy female offspring's ratio by transfer of pre-selected transferrable blastocyst that was produced by pre-selected X-bearing semen with OPU derived oocytes. Elite dairy female cow is demanded strongly compared with male, the so called, farmer wants to produce only an elite female dairy offspring as a candidate female dairy cow for producing milk. In our study, we selected 2 elite dairy bull semen from National Agricultural Cooperative Federation to pre-select X-bearing semen and 5 elite dairy female cows as donor for collecting of OPU derived oocytes. OPU derived embryo production system was carried out an aspiration of immature oocytes from 5 donor cows 2 times per week, total 200 times for 2 to 7 months by an ultrasonographic guided follicular aspiration system and then produced in vitro-produced blastocysts by in vitro maturation, fertilization and culture. Dairy donor semen selected H-319, 320 bull in National Agricultural Cooperative federation was sorted X-bearing semen by flow-cytometer and frozen for using IVF with OPU derived oocytes. Donor cows were selected 5 elite dairy cows from Gyeongju Dairy Cow Community and then disease tests such as 4 kinds of disease before selecting was checked. Oocyte proportion of grade 1 to 3 from total collected oocytes was significantly lower in donor A and B than those in donor C, D and E (82.16 and 70.03% vs. 90.0, 91.78 and 93.57%), respectively (p<0.05). However, number of oocytes per session in donor A, C and E was significantly higher than those in donor B and D ($7.77{\pm}3.26$, $5.85{\pm}2.10$ and $7.03{\pm}2.14$ vs. $4.68{\pm}2.61$ and $5.21{\pm}1.97$ oocytes), but donor A was significantly higher than donor C (p<0.05). Development to blastocyst in donor B, C and E was significantly higher than those in donor A and D (31.0, 25.0 and 25.0% vs. 14.3 and 4.5%), but donor A was not different in donor C and E (p<0.05). Nine out of 10 blastocysts (90.0%) derived from OPU blastocysts were confirmed male embryos that was induced with Y-bearing semen to confirm sex ratio only. Total 96 blastocysts derived from female bearing semen were transferred into synchronized recipients and then confirmed 42 recipients (43.8%) pregnancy rate, 36 offspring (37.5%) and 91.7% female sex ratio (33 female vs. 3 male offspring). Taken together all data, elite dairy female offspring could be produced effectively by in vitro production system between pre-selected x-bearing semen and OPU derived oocytes that would be influential breeder in the breeding of dairy farm to increase effectively elite dairy offspring ratio as well as net income in the dairy farmer.

• The Journal of Korean society of community based occupational therapy
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• v.4 no.1
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• pp.75-84
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• 2014

Objective : This study intends to suggest an effective clinical intervention method for stroke patients by applying a trunk stabilization training program to a single stroke patient and investigating and analyzing the effects of the program on postural control and activities of daily living. Methods : The subject of this study was a 75 year-old female stroke patient hospitalized in C Hospital located in Gyeongju, Gyeongsangbuk-do. As for the research design, A-B-A reversal design was used with a single subject design; and the research period was a total of five weeks from April 21, 2014 to May 23, 2014. As for the research process, a total of 15 sessions were carried out including three sessions of baseline(A), nine sessions of an intervention period(B), and three sessions of maintenance(A'); and the trunk stabilization program was applied during the intervention period. To evaluate the participant's postural control and activities of living life, the Postural Assessment Scale for Stroke(PASS) and the modified Barthel Index(MBI) were used. Visual analysis was used in which collected data were plotted on a graph, using Microsoft Office Excel 2013. Results : In the postural control test, the mean scores improved from 11.7 in the baseline phase to 14.8 in the intervention phase and 15.3 in the maintenance phase. In the evaluation of activities of daily living, the score improved from 66(medium dependence) during the baseline period to 80(low dependence) after intervention and at the maintenance phase. Conclusion : It was found that the trunk stabilization training program showed effects on the stroke patient's postural control or alignment, and furthermore a beneficial improvement in the patient's performing the activities of daily living, as well.