• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.441-447
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• 2021

It were investigated changes in internal and external temperature, relative humidity using tyvek, weedstop, and 35% shading net as covering material to reduce the freezing damage of 'Shiranui' hybrid mandarin grown in open field. It were also evaluated canopy covering effect and LT₅₀ of leaves by covering material when it was cold at -2℃. In tyvek, temperature difference between inside and outside was low at the height of 1.5m and was high at 0.4m. The relative humidity differed greatly between day and night, and was high at 6-8 a.m. At -2℃, Sum of temperature at the height of 1.5m of canopy for 24-hour after covering were at 3.4℃ higher in tyvek than in control. The LT₅₀ of leaves was at 1.51℃ in tyvek, 1.33℃ in withstop, and 1.61℃ in 35% shading net lower than in control. Considering thermal insulation and relative humidity in canopy, tyvek is expected to reduce low temperature damage when covering after making a fine hole for ventilation.

• Korean Journal of Construction Engineering and Management
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• v.20 no.2
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• pp.113-118
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• 2019

Recently, the maintenance concept of infrastructure has been changed from the stability management of the structure determined by the safety inspection of the existing facilities to the asset management related to evaluating and managing the performance of the facilities. For management of the property of the facilities, it is necessary to efficiently classify their information for the maintenance and service level of the facilities and to manage them. In the case of power plant facility, especially, it is a complex structure, which is constructed in a various component and detail. In this study, therefore, the components of power plant facility were classified into facilities, spaces, parts, and elements considering the type of integrated construction classification system in Korea. To reflect the deterioration rate of the facility in accordance with environmental conditions such as airborne salt and humidity etc., it was classified by adding direction, interior, and exterior condition of each component not to be considered in the existing classification system for its effective and systematic maintenance, since it is generally located in the coastal area due to the operation of the power generation structure. The classification system developed in this study can be used as fundamental data for development of the computer system for asset management of power plant facility.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.212-217
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• 2019

Bacterial wilt caused by Ralstonia solanacearum is a major disease that affects tomato plants widely. R. solanacearum is a soil born pathogen which limits the disease control measures. Therefore, breeding of resistant tomato variety to this disease is important. To identify the susceptible variety, degree of disease resistance has to be determined. In this study, micro sap flow sensor is used for accurate prediction of resistant degree. The sensor is designed to measure sap flow and water use in stems of plants. Using this sensor, the susceptibility to bacterial wilt disease can be identified two to three days prior to the onsite of symptoms after innoculation of R. solanacearum. Thus, this find of diagnosis approach can be utilized for the early detection of bacterial wilt disease.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.203-215
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• 2019

This study was conducted to identify the utilization of public health centers, as well as the individual characteristics and regional characteristics that affect their utilization based on data from the 2016 Community Health Survey, National Statistical Portal, and National Institute of Environmental Research. Independent samples t-tests, variance analysis, and multiple logistic regression analysis were used for analysis. Hierarchical multiple regression was used to analyze individual and regional characteristics. The results of hierarchical multiple regressions revealed that aged regions, women, older age individuals, respondents with lower education level and income level, walking practitioners, nutrition label readers, individuals experiencing depression, those who have received health checkups, those who are not covered by essential care, those who have spouses, and basic livelihood beneficiaries have increased use of public health centers. However, the use of public health centers decreased in stressors, and regions in which the population per 1,000, number of health care workers, health and welfare budget, fiscal independence, and unemployment rate were above the national average. As above, the central government and local governments need to analyze not only individual characteristics such as health behavior and psychological factors, but also regional characteristics, when establishing local health care policy.

• Journal of the Korean GEO-environmental Society
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• v.19 no.12
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• pp.41-46
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• 2018

The wireless sensor network system has the advantage of confirming the behavior of the entire facility by improving the disadvantages of conventional monitoring system. As a result, it is widely proposed as safety diagnosis and measurement of structures, water management systems, and management systems for dam structures. However, there is a lack of research that can evaluate the condition of facilities such as safety at the same time as monitoring. In this study, it is proposed a wireless sensor network system which can evaluate the behavior characteristics of facilities and evaluate the safety status for improving the technical disadvantages on conventional monitoring system. The geotechnical risk factors for the reservoir dam facility were evaluated and the limit values for the risk factors causing the failure of the facility were set. In other words, the system was set up so that the risk factors can be measured and the limit status can be evaluated immediately for each factor. In this study, numerical analysis is carried out for seepage and slope stability analysis using the typical cross section for reservoir dams. The stress-porewater coupling finite difference numerical analysis is performed for establishing the limit displacement for reservoir dam structures. It is developed a system that can estimate the time to reach the critical value by regression analysis using the measured datas.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.833-844
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• 2018

Dual energy X-ray absorptiometry is mainly used as an X-ray test method. For equipment manufactured GE and Hologic, cross-calibration analyses (CCA) of machines from the same manufacturer and between units from different manufacturers have been conducted, but the CCA of equipment manufactured in Korea are inadequate. Through CCA, we present a formula of the intersections between the Korean medical equipment company (KEC) with GE and Hologic manufactured DXA, and among the KEC DXA. The CCA was conducted for the European Spine Phantom on DXA from four KEC and three global medical equipment company (GEC) manufacturers. We compared bone mineral density (BMD) values and calculated the CCA equation by linear regression analysis. The standard-deviations (SD) of the BMD values were highest for the Dexxum T for the low, medium, and high spine, which were 0.030, 0.029, and 0.037, respectively. The smallest SD in the low and medium vertebrae were 0.005 and 0.004 for the Horizon Ci, respectively, and 0.005 for the Osteo Pro Max in the high vertebrae. Based on the intersection equations of the KEC DXA established in this study, CCA of various KEC DXA should be established for more accurate follow-up of BMD tests in clinical environments.

• Journal of Korea Technology Innovation Society
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• v.21 no.3
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• pp.938-968
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• 2018

Korea's basic research has been rapidly expended in both quantative and qualitative aspect since establishment of 'the Korea Science & Engineering Foundation' in 1977, proclaiming of 'the First Year of Basic Research Promotion' and enactment of 'the Basic Sciences Promotion Act' in 1989. Despite the continuous increment of government basic research funding, the problem of low perceptions of university researchers on the funding increment has been constantly raised. Based on an intrinsic review on the core issues are diagnosed based on Korean academics' basic research status analysis and future challenges are proposed based on the precedent diagnoses. The six key issues that need to take the next step in Korean academics' basic research are as follows: (1) basic research investment in universities, (2) appropriate research expenses for supporting individual researcher, (3) basic research funding allocation method, (4) maintaining the sustainable success rate of research projects, (5) systematic and strategic support for excellent researchers, (6) creating research-immersive environment. The five challenges to promote basic research in academics are as follows: (1) increasing in university research expenses, (2) diversification of basic research funding allocation method, (3) establishment of research field-specified support system and predictable principles, (4) stable and sufficient support for outstanding researchers, (5) reducing burden on research administration.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.122-143
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• 2010

The Shilla Stone Monument in Jungseongri was found during the road-construction in Pohang. It has approximately two hundreds of letters inscribed on the surface of one side, and it is estimated to be older than Shilla Stone Monument in Naengsuri which had been known for the oldest stele in Shilla Period. This monument is made of fine to medium-grained biotite granite, while the Shilla Stone Monument in Naengsuri is made of fine-grained granodioritic porphyry bearing feldspar and amphibole phenocrysts. Both rock types of the monuments are interpreted to be cognate with biotite granite in Shinkwangmyeon, and with granodioritic porphyry in Gigyemyeon. They are characterized by xenolith and miarolitic cavity. Damage aspects in both monuments are discoloring, cracking and breaking. These damages do not cause structural instability of the monuments, but attenuate aesthetic value. Black and brown discoloring contaminants on the surface of the Jungseongri Monument contain a high amount of manganese and iron. As a result of ultrasonic test, both monuments were evaluated to be medium-weathered (MW), although the velocity of the Shilla Monument in Jungseongri was slightly lower than the Shilla Monument in Naengsuri. This is because the Monument in Juengseongri had been exposed to outdoor environment for long time until the discovery. It is necessary for Shilla Monuments to be protected by appropriately environmental control and management.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.620-625
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• 2018

Pyropia yezoensis is one of the most extensively cultivated seaweeds used as food in Korea. However, the quality and yield of Pyropia farms are frequently affected by outbreaks of thallus discoloration. The objective of this study was to develop a simple and rapid method to evaluate P. yezoensis discoloration caused by nutrient deficiencies. A colorimeter was used to quantify the color of P. yezoensis in nutrient deficient media over 10 days. Quantitative values of lightness (L), redness (a), and yellowness (b) measured with a colorimeter were used as indicators of P. yezoensis discoloration. The vacuoles of P. yezoensis were observed at 4 days and swelled gradually from 6 days onward. The three colorimeter parameters L, a, and b values showed significantly different values with culture period. The lightness (L) value was darker initially, and continued to lighten over culture period. The yellowness (b) value increased, but the redness (a) value decreased throughout this study. The a/b ratio and redness (a) values from the colorimeter were important P. yezoensis color change indicators. The discoloration group of P. yezoensis had quantitative values for parameters of L above 70, a below 2.6, and b above 15.0. The results of this study showed that quantitative colorimetric measurements can be used as tools for simple and rapid detection of P. yezoensis discoloration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.527-534
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• 2019

Several types of mathematical analysis methods are used for port waterway risk assessment based on marine traffic volume. In Korea, a marine traffic congestion model that standardizes the size of the vessels passing through the port waterway is applied to evaluate the risk of the waterway. For example, when marine traffic congestion is high, risk situations such as collisions are likely to occur. However, a scientific review is required to determine if there is a correlation between high density of maritime traffic and a high risk of waterway incidents. In this study, IWRAP Mk2(IALA official recommendation evaluation model) and a marine traffic congestion model were used to analyze the correlation between port waterway risk and marine traffic congestion in the same area. As a result, the linear function of R2 was calculated as 0.943 and it was determined to be significant. The Pearson correlation coefficient was calculated as 0.971, indicating a strong positive correlation. It was confirmed that the port waterway risk and the marine traffic congestion have a strong correlation due to the influence of the common input variables of each model. It is expected that these results will be used in the development of advanced models for the prediction of port waterway risk assessment.