• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2914-2922
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• 2014

To study the risk factors and effect of gastric cancer screening, case-control study was conducted. From June 2007 to December 2011, 580 newly diagnosed gastric cancer (342 advanced gastric cancer, 171 early gastric cancer) patients were enrolled at the department of general surgery in a university hospital. History of gastric examinations and possible risk factors were collected through interviews with structured questionnaire and reviewed medical chart. Comparing advanced cancer and early gastric cancer were analysed by chi-square test and logistic regression. The results showed that aged 70 and over (OR 2.393; 95%CI 1.329-4.310), Ex-smoker (OR 1.612; 95%CI 0.970-2.680), blood type A (OR 1.784; 95%CI 1.035-3.075), and H. pylori infection (OR 1.699; 95%CI 0.905-3.191) were important risk factors for advanced gastric cancer compared to early gastric cancer. Weight loss (OR 2.752; 95%CI 1.333-5.684) and indigestion (OR 1.574; 95%CI 1.069-2.319) were also important sign and symptom. Although the results cannot find effect of screening, national policies on early cancer detection must conduct.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.84-95
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• 1998

Apple Marssonina blotch, caused by Diplocarpon mali, which has been increasing on apple trees and become one of the most serious diseases on apple trees in Korea since the begining of 1990's. In this study, ecology of Marssonina blotch including disease incidence and spore dispersals was surveyed from 1992 to 1995 in Kyungpook, and factors influencing the incidence of the disease were analyzed. Marssonina blotch began to occur on apple leaves in June and was observed commonly in most of apple orchards after August, and increased rapidly in September. The incidence of this disease was high at the year of low temperature and a lot of precipitation. The conidia discharge began to occur in May and continued to October, and the peak period of spore release was in August and usually more than 70% of total spore release of the year released from August to September. The incidence of the disease was high in the northern and mountain are as such as Yeongjoo, Chungsong, Andong, and relatively low in the southern areas such as Kunwi, Yongchon. Jonathan cultivar was the most susceptible to Marssonina blotch, and Jonagold, Sekaiichi was secondly susceptible and the next Fuji was more susceptible than Tsugaru. The incidence of the disease was relatively high in orchards which cultivation management of irrigation, drainage, air circulation, fertilization, and fungicide spraying were poor.

• Journal of Korean Society of Forest Science
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• v.20 no.1
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• pp.45-50
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• 1973

This study was investigated the methods of vegetative propagation for new Lespedeza varieties. Experimental matterials were used 6 Lespedeza species; L. maximowiczii, L. cyrtobotrya, L. angustifolioides, L. bicolor, L. maximowiczii var. tomentella, and L. japonica var. intermedia. In April a year branches were cut 15-20cm length and 3-4mm thickness and planted in sand bed (depth 150cm) to be sterilized by the 0.1% solution of Uspulun. And then the cutting beds were irrigated and shaded. The results are as follows. 1. The rooting rates of the cuttings could be found so variable among varieties from 69% of L. maximowiczii var. tomentella to 50.3% of L. japonica var. intermedia. 2. The growth performance showed statistically significant difference at 1% level among varieties. L. maximowiczii was the best, while L. japonica var. intermedia showed the wrost growth performance of them. 3. The average number of roots with more than 5 cm length per stock was revealed statistically significant difference at the 1% level among varieties from the greatest number of 6.4 of L. maximowiczii var. tomentella to the smallest number of 2.3 of L. japonica var. intermedia. 4. Total average length of the roots per stock was statistically significant so different at 1% level from the longest 279.8cm of L. maximowiczii var. tomentella to the shortest 41.1cm of L. japonica var. intermedia. 5. The average ndules with more than 1 mm in diameter per stock was statistically significant so different at 1% level among varieties from the greatest number of 34.4 of L. maximowcizii to the smallest numqer of 4.6 of L. japonica var. intermedia.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.629-647
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• 2018

This study was carried out to investigate the economic value of organic rice production using gelatin chitin microorganisms in eco-friendly complex, Gongsan, Naju city. The soil condition of experiment paddy field was Jeonbuk series and silt loam with a slightly poor drainage. Except for the high effective silicate, the chemical characteristics of soils used were included in the optimum range of paddy soils in Korea. In growth, plant length, tiller number, ear number, and ear length were observed to be higher in conventional paddy fields than organic paddy fields. However, number of grain per panicle and grain filling ratio (%) were higher in organic paddy fields than conventional paddy fields. Incidences of diseases and insect pests were slightly higher in the organic paddy fields. Water weevil, sheath blight, rice leaf roller and rice blast were more occurred in organic paddy field. On the other hand, false smut was higher occurred in conventional paddy field. There was a significant negative correlation between rice sheath blight and rice leaf roller, and rice yield. In the milled rice quality, the quality of organically cultivated milled rices was lower by the increase of broken rice than that of conventionally cultivated milled rices. The quality and palatability of rice were higher in organic cultivation with decreasing of protein content. Net income of conventionally and organically cultivated rice was 360,000 won/10a and 610,000 won/10a, respectively. Premium net income of the organically cultivated rice was 68%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.75-83
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• 2019

In order to fulfill the obligation to voluntarily reduce greenhouse gas emissions under the Paris Climate Agreement, the proportion of coal and nuclear power generation is reduced worldwide and national efforts are being made to spread renewable energy including solar power generation. Korea also intends to increase the proportion of renewable energy generation to 30~35% by 2040 by introducing laws and regulations. In addition, while the country is trying to apply solar power generation to sidewalks and roads, there is no research related to it in Korea. Therefore, as a precedent study to develop solar power generation roads, solar power generation concrete blocks applicable to sidewalks and plazas were developed and the applicability was evaluated by constructing them on the site. As a result of indoor experiment, compressive strength was measured by 25.5~35.7MPa and flexural strength was measured by 5.1~10.5MPa, which showed that all domestic standards were satisfied. However, the higher the unit cement amount, the lower the strength was measured according to the mixing of the broken fine aggregate. The absorption rate was 5.7%, which satisfied the domestic standard of 7% or less. As a result of the freeze-thawing test, the reduction rate of the compressive strength after 100 cycles was up to 6.3%. As a result of measuring the settlement amount after construction, the maximum of 2.498mm was measured and irregular settlement occurred in the overall area, which is because the resolution of the sand layer was poor during construction. Maintenance techniques of sidewalk concrete block and solar panel need to be established more efficiently through long-term operation in the further.

• Geophysics and Geophysical Exploration
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• v.22 no.3
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• pp.149-159
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• 2019

Borehole elemental concentration logging, measuring neutron-induced gamma rays by inelastic scattering and neutron capture interactions between neutron and formation, delivers concentrations of the most common elements found in the minerals and fluids of subsurface formation. X-ray diffraction and X-ray fluorescence analysis from core samples are traditionally used to understand formation composition and mineralogy, but it represents only part of formations. Additionally, it is difficult to obtain elemental analysis over the whole intervals because of poor core recovery zones such as fractures or sand layers mainly responsible for groundwater flow. The development of borehole technique for in situ elemental analysis plays a key role in assessing subsurface environment. Although this technology has advanced consistently starting from conventional and unconventional resources evaluation, it has been considered as exclusive techniques of some major service company. As regards domestic research and development, it has still remained an unexplored field because of some barriers such as the deficiency of detailed information on tools and calibration facility for chemistry and mineralogy database. This article reviews the basic theory of spectroscopy measurements, system configuration, calibration facility, and current status. In addition, this article introduces the domestic researches and self-development status on borehole elemental concentration tools.

• Korean Journal of Construction Engineering and Management
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• v.22 no.3
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• pp.61-68
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• 2021

This study analyzed the influencing factors for urban redevelopment projects with a relatively long project duration in the context of Seoul's increasing urbanization rate and aging. Among the business areas that have been designated since 2005 and have been approved for the management and disposal plan of the entire Seoul area, 75 business areas have been set as targets. A hedonic price model was used to analyze the project area, economic, and locational characteristics as independent variables with the project duration from designation of zones to approval of management and disposal plans as dependent variables. As a result of the analysis, the smaller the project area, the larger the area occupied per union member, the larger the land price change rate, and the smaller the KOSPI index, the shorter the required period. This study has the distinction of empirically analyzing the effect of characteristic variables considering size and economic and locational characteristics on period. It provides implications that the area of the business area, the number of union members, and economic conditions should be considered when establishing a business area.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.494-507
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• 2021

With the increasing use of TBM, research has recently been conducted in Korea to analyze TBM data with machine learning techniques to predict the ground in front of TBM, predict the exchange cycle of disk cutters, and predict the advance rate of TBM. In this study, classification prediction of rock characteristics of slurry shield TBM sites was made by combining traditional rock classification techniques and machine learning techniques widely used in various fields with machine data during TBM excavation. The items of rock characteristic classification criteria were set as RQD, uniaxial compression strength, and elastic wave speed, and the rock conditions for each item were classified into three classes: class 0 (good), 1 (normal), and 2 (poor), and machine learning was performed on six class algorithms. As a result, the ensemble model showed good performance, and the LigthtGBM model, which showed excellent results in learning speed as well as learning performance, was found to be optimal in the target site ground. Using the classification model for the three rock characteristics set in this study, it is believed that it will be possible to provide rock conditions for sections where ground information is not provided, which will help during excavation work.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.55-61
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• 2023

This study aims to develop CLSM fill material for emergency restoration using landfill coal ash. As a result of examining physical properties such as particle size distribution and fines content of landfill coal ash, bottom ash, fly ash, and general soil were mixed, and SP was found to have a density of 2.03 and a residual particle pass rate of 7.8 %. CLSM materials that secure fluidity in unit quantities without using chemical admixtures such as glidants and water reducing agents have a high risk of material separation due to bleeding. As a result of this experiment, it was found that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for 4 hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it is judged that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.27-40
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• 2006

Damage of cut-and-cover tunnel lining can be attributed to physical and mechanical factors. Physical factors include material property, reinforcement corrosion, etc. while mechanical factors include underground water pressure, vehicle loads, etc. This study is limited to the modeling of rigid circular cut and cover tunnel constructed at a depth of $1.0{\sim}1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. In this study, only damages due to mechanical factors in the form of additional loads were considered. Among the different types of additional, excessive earth pressure acting on the cut-and-cover tunnel lining is considered as one of the major factors that induce deformation and damage of tunnels after the construction is completed. Excessive earth pressure may be attributed to insufficient compaction, consolidation due to self-weight of backfill soil, precipitation and vibration caused by traffic. Laboratory tunnel model tests were performed in order to determine the earth pressure acting on the tunnel lining and to investigate the applicability of existing earth pressure formulas. Based on the difference in the monitored and computed earth pressure, a factor of safety was recommended. Soil deformation mechanism around the tunnel was also presented using the picture analysis method.