• Composites Research
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• v.33 no.5
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• pp.296-301
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• 2020

Laminated composite materials have excellent in-plane properties, but are vulnerable in thickness directions, making it easy to delamination when bending and torsion loads are applied. Thickness directional reinforcement methods of composite materials that delay delamination include Z-pinning, Stitching, Tufting, etc., and typically Z-pinning and Stitching method are commonly used. The Z-pinning is reinforcement method by inserting metal or carbon pin in the thickness direction of prepreg, and the conventional stitching process is a method of reinforcing the mechanical properties in the thickness direction by intersecting the upper and lower fibers on the preform. In this paper, I-fiber stitching method, which complement and improve weakness of Z-pinning and Stitching method, was proposed, and the static strength of composite single-lap joints using I-fiber stitching process were evaluated. The single-lap joints were fabricated by a co-curing method using an autoclave vacuum bag process. The thickness of the composite adherend was fixed, and 5 types of specimens were manufactured with varying the stitching pattern (5×5, 7×7) and angle (0°, 45°). From the test, the failure load of the specimen reinforced by the I-fiber stitching process was increased by up to 143% compared to that of specimen without reinforcement.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.328-336
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• 2013

This study was conducted to evaluate imported tomato $F_1$ cultivars as breeding materials for the resistance to Tomato yellow leaf curl virus (TYLCV) by molecular markers and bioassay. From marker genotyping and disease evaluation of 40 $F_1$ cultivars, most of the cultivars declared as TYLCV-resistance carried heterozygous marker genotype for the TYLCV resistance genes Ty-1, Ty-3, or Ty-3a, and showed low disease rates. Whereas, 4 of 5 $F_1$ cultivars declared as intermediate resistance showed marker genotype for susceptibility and disease rates ranged 18.1-33.3%. However, the xx cultivars showed inconsistency in marker genotype and disease rate. Characterization of horticultural traits of the $F_1$ cultivars with TYLCV-resistance indicated that large-size fruit cultivars were higher in yield and similar in sugar contents and solid-acid ratio compared to a control cultivar preferred in the domestic market, although hardness remained to be a problem. On the other hand, cherry tomato cultivars showed lower yield and brix, but longer internode compared to a control cultivar, indicating that breeding for TYLCV-resistance using these cultivars will require more efforts and time compared to large-sized.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.44-50
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• 2009

The occurrence of endocrine disrupting compounds (EDCs), chemicals that interfere with human hormone system, are increasing in the freshwater, waste water and subsurface as well. In this study, we determined the reactivity of three EDCs in the presence of birnessite. In aqueous phase, bisphenol A, 2,4-dichlorophenol and 17${\beta}$-estradiol, which possesses phenoxy-OH, were very rapidly transformed by birnessite: up to 99% of initial concentrations (50 mg/L for bisphenol A, 100mg/L for 2,4-dichlorophenol, and 1.5mg/L for 17${\beta}$-estradiol) were destroyed within 60 minutes. Especially, bisphenol A was the most reactive chemical, disappearing by 99% in a few minutes. The reaction occurred on the surface of birnessite, showing a linear increase of first-order kinetic constants with the increase of the surface area of birnessite. In soil slurry phase, the reactivity of birnessiteto EDCs was faster than in aqueous phase probably due to the cross coupling reaction of phenoxy radicals with soil organic matter. Considering the rapid transformation of the EDCs in the both phases, this oxidative cross coupling reaction mediated by birnessite would be an effective solution for the remediation of EDCs in environmental media, especially in soil.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.488-492
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• 2001

To investigate changes of components in salt-fermented big eyed herring, Harengula zunasi sauce during fermentation, various chemical properties were examined at $2\~3$ months intervals during 18 months of fermentation. The hydrolytic degree increased sharply until 5 months of fermentation and showed the gentle increasement after that. On the other hand, the content of total and amino nitrogen increased gradually during 18 months of fermentation, The hypoxanthine and uric acid were the most abundant in ATP related compounds, ranging from $81.7\%\;to\;90.1\%$. After 18 months of fermentation, sauce was rich in free amino acids such as glutamic acid, aspartic acid, alanine, lysine, threonine in that order.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.555-562
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• 2016

The objective of the present study is to evaluate the shear transfer capacity of transverse reinforcement at the concrete interfaces with smooth construction joint. The transverse reinforcing bars were classified into two groups: V-type for the arrangement perpendicular to the interface and X-type for inclined-crossing arrangement. The transverse reinforcement ratio at the interface varied from 0.0045 to 0.0135 for V-type and 0.0064 to 0.0045 for X-type. The mechanism analysis proposed for monolithic concrete interface, derived based on the upper-bound theorem of concrete plasticity, was modified to evaluate the shear friction capacity of concrete interfaces with smooth construction joint. Test results showed that the specimens with X-type reinforcement had lower amount of relative slippage at the interface and higher shear friction capacity than the companion specimens with V-type reinforcement. This observation was independent of the unit weight of concrete. The mean and standard deviation of the ratios between the experimental shear friction strength of smooth construction joints and predictions obtained from the proposed model are 1.07 and 0.14, respectively.

• Journal of the Korean earth science society
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• v.40 no.6
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• pp.599-605
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• 2019

Rice yield (kg 10a^-1) in South Korea was estimated by meteorological variables that are influential factors in crop growth. This study investigated the possibility of anticipating the rice yield variability using a simple but an efficient statistical method, a multiple linear regression analysis, on the basis of the annual variation of meteorological variables. Due to heterogeneous environmental conditions by region, the yearly rice yield was assessed and validated for each province in South Korea. The monthly mean meteorological data for the period 1986-2018 (33 years) from 61 weather stations provided by Korean Meteorological Administration was used as the independent variable in the regression analysis. An 11-fold (leave-three-out) cross-validation was performed to check the accuracy of this method estimating rice yield at each province. This result demonstrated that temporal variation of rice yield by province in South Korea can be properly estimated using such concise procedure in terms of correlation coefficient (0.7, not significant). Furthermore, the estimated rice yield well captured spatial features of observation with mean bias of 0.7 kg 10a^-1 (0.15%). This method may offer useful information on rice yield by province in advance as long as accurate agro-meteorological forecasts are timely obtained from climate models.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.446-457
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• 2019

The purpose of this study was to analyze the association between family members and adolescent boys smoking. The data were evaluated by frequency analysis, 𝑥² test and logistic regression analysis using 27,276 people who responded to the 14th(2018) Korean Youth Risk Behavior Survey. Among male students, the nonsmoking rate was 91.5% and the smoking rate was 8.5%(2.5% of occasional smoking and 6.0% of frequent smoking). The study results showed that the smoking status of male students was varied significantly according to the number of smokers among the family members(p<0.001). Meanwhile, smoking based on the characteristics of socio-demographic factors was affected by grades, school records, economic status, and parents' educational background(p<0.001). Smoking by health factors showed a significant difference in alcohol consumption, suicidal thoughts, depression experiences, stress recognition, frequency of breakfast consumption, level of fatigue after sleep, and subjective perception of health(p<0.001). Male smokers were more likely to smoke when two family members smoked than only one(p<0.001). These results confirmed that smoking in boys was affected by the smoking status of family members and suggested that the smoking cessation program of family smokers can be effective in designing smoking cessation prevention and smoking cessation projects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3931-3942
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• 2009

This study as a descriptive survey was to investigate recognition and attitudes on ethical issues for DNR of 119 rescue party who are working on the field, and to develop an objective framework which helps rescue team to manage DNR patients. Data were collected from the structured questionnaire, and subject were 226 rescue party in Jeollabuk-do area in Korea. Study was practiced from May 6 through June 20, 2009, and the data were analyzed by frequency, percentage, $x^2$-test, crosstabs using SPSS Win 12.0. The results indicated that ethical attitudes on subjects' factors(sex, age, religion, marital status, clinical working career, current working area, current position, educational experiences for ethics and values, DNR education places, DNR implication experience, and DNR consulting demands) were statistically significant. Therefore, following researches will be necessary in order to consider measures about DNR based on this study.

• Korean Journal of Remote Sensing
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• v.27 no.1
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• pp.59-68
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• 2011

The analysis of optimal infiltration path is one of the representative fields in which the GIS technology can be useful for the military purpose. Usually the analysis of the optimal path is done with network data. However, for military purpose, it often needs to be done with raster data. Because raster data needs far more computation than network data, it is difficult to apply the methods usually used in network data, such as Dijkstra algorithm. The genetic algorithm, which has shown great outcomes in optimization problems, was applied. It was used to minimize the detection probability of infiltration route. 2D binary array genes and its crossover and mutation were suggested to solve this problem with raster data. 30 tests were performed for each population size, 500, 1000, 2000, and 3000. With each generation, more adoptable routes survived and made their children routes. Results indicate that as the generations increased, average detection probability decreased and the routes converged to the optimal path. Also, as the population size increases, more optimal routes were found. The suggested genetic algorithm successfully finds the optimal infiltration route, and it shows better performance with larger population.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.31-42
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• 2004

This study develops Accident Modification Factors (AMF) of countermeasures with Baysian method which are newly proposed for reducing Roadway-Rail grade crossing accidents. This study proposes a new "Bayesian Analytical Framework" for countermeasure assessment which combines "Subjective" Prior Information with "Logical" based Information. The newly proposed "Bayesian Analytical Framework" consists of the following three steps: The 1st step - Countermeasure Selection, Choice of Participants, Selection of Crashes; The 2nd step-Development of Crash History Manual and Countermeasure Evaluation Manual; The 3rd step-Development of AMFs through sound statistical tests. This study used the Komogorov-Smirnov(K-S) Test to determine whether two unknown distribution functions associated with the two populations are identical. The results of the study are that individual responses did not meet the K-S test of identical distributions. while individual vs. group distributions are identical. This indicates that combining the input of several people reduces the impact of individual subjectivity and assumptions and is important for developing a repeatable distribution to develop sound AMFs of countermeasures for reducing Roadway-Rail grade crossing accidents. The procedures of the AMF development conducted in this study can be used to estimate the safety effects of countermeasures for road segments and intersections, in addition to Roadway-Rail grade crossings.