• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.6
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• pp.944-950
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• 2015

The purpose of this study was to provide a basis for the management of traditional Doenjang by analyzing characteristics of volatile compounds in local Doenjang certified as a traditional food. The main compounds in Doenjang were acids, esters, aldehydes, and pyrazines, whereas relatively high intensities of acetic acid, ethyl alcohol, benzaldehyde, ethyl acetate, ethyl 2-methyl butanoate, 2,5-dimethyl pyrazine, and tetramethylpyrazine were detected among identified compounds. The analysis revealed that the composition of basic volatile compounds in Doenjang was similar, but isovaleric acid, 2-methylbenzaldehyde, tetramethylpyrazine, benzaldehyde, ethyl alcohol, ethyl caprylate, furfural and butanoic acid can serve as marker compounds for quality evaluation since they were specifically abundant in only some kinds of Doenjang. As a result, the quality status of Doenjang certified as a traditional food was determined by constructing a database of the volatile compounds, which can be suggested as a quality control method.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.91-98
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• 2019

The research focused on plastic surgery clinics in Seoul, which recently responded to foreign patients who wanted to get plastic surgery, to recognize the need for the use of mobile healthcare applications to promote medical tourism and to see the expected effects in the future. For the analysis of data, SPSS 21.0 was used. Based on personal characteristics and medical institution characteristics, the future expected effects of using mobile healthcare applications were analyzed to find ways to help vitalize medical tourism. The result showed that the more mobile applications they wants to use in the future and the higher the number of foreign patients of the medical institutions, the more positive the expectation on the use of mobile healthcare application in the future. Also, the higher evaluation on the need for mobile healthcare application, the more helpful in vitalizing the medical tourism in the future, and the higher the positive awareness. I hope that this research will provide an IT foundation for the and expansion of mobile service app on demand analysis and service utilization of medical workers in order to promote medical tourism.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.39-46
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• 2022

As the limit state design method is applied as the design method of reinforced concrete structure, the ultimate state is considered when analyses or designing. In fact, when the reinforced concrete member is bent, there is a confining effect by stirrup, but the material curve of unconfined concretes applied when designing. In this study, to evaluate the suitability of the confined concrete model for flexural members, a 4-point bending test was conducted on RC simple beam with a double-reinforced rectangular cross-section, and the behavior of the member after yield was analyzed in detail using image processing method. For detailed analysis, the DIC method was adopted as an image analysis method, and the validity of DIC method was verified by comparing the measurement results with the LVDT. The distribution of the strain on the concrete surface calculated as a result of the DIC method could be obtained, and the average strain distribution of the cross-section was calculated. Using the average strain distribution, the stress distribution applied existing confined concrete model as a material curve could be derived. Through the comparison of the experimental results and the existing model application results, the suitability of the confined concrete model for RC flexural members having a rectangular cross-section was evaluated.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.93-102
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• 2023

This study conducted an effect evaluation before and after the installation of a vehicle information guidance system that provides drivers with information about vehicle speed and the presence or absence of pedestrians near pedestrian crossings. There are three types of scenarios: when no information is provided to the driver (S1), when only the vehicle driving speed is provided (S2), and when pedestrians are present on the pedestrian crossing and when both vehicle driving speeds are provided (S3). did. As a result of the survey, the speed reduction rate of the vehicle was found to be about 0.4~0.7km greater in S2 and S3 that provide information to the driver than in scenario S1. In addition, in the scenario S3, the speed reduction rate is 0.2km higher than that in the case where there are pedestrians near the pedestrian crossing, which further reduces the vehicle speed. Statistical analysis also showed that there was a difference in the speed reduction rate of the average vehicle for the three scenarios, and that the speed reduction rate was large in the presence of pedestrians.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.279-289
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• 2022

Since the frequency of heavy rainfall is increasing due to climate change, water levels in the river exceed past historical records. The rating-curve is to convert water level into flow dicscharge from the regression analysis of the water level and corresponding flow discharges. However, the rating-curve involves many uncertainties because of the limited data especially when observed water level exceed past historical water levels. In order to compensate for insufficient data and increase the accuracy of flow discharge data, this study estimates the flow discharge in the river computed mathematically using Monte Carlo simulation based on a 1D hydrodynamic numerical model. Based on the existing rating curve, a random combination of coefficients constituting the rating-curve creates a number of virtual rating curve. From the computed results of the hydrodynamic model, it is possible to estimate flow discharge which reproduces best fit to the observed water level. Based on the statistical evaluation of these samples, a method for mathematically estimating the water level and flow discharge of all cross sections is porposed. The proposed methodology is applied to the junction of Yochoen Stream in the Seomjin River. As a result, it is confirmed that the water level reproducibility was greatly improved. Also, the water level and flow discharge can be calculated mathematically when the proposed method is applied.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.114-123
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• 2023

With the development of computer vision technology, video sensors such as CCTV are detecting incident. However, most of the current incident have been detected based on existing fixed imaging equipment. Accordingly, there has been a limit to the detection of incident in shaded areas where the image range of fixed equipment is not reached. With the recent development of edge-computing technology, real-time analysis of mobile image information has become possible. The purpose of this study is to evaluate the possibility of detecting expressway emergencies by introducing computer vision technology to dash cam. To this end, annotation data was constructed based on 4,388 dash cam still frame data collected by the Korea Expressway Corporation and analyzed using the YOLO algorithm. As a result of the analysis, the prediction accuracy of all objects was over 70%, and the precision of traffic accidents was about 85%. In addition, in the case of mAP(mean Average Precision), it was 0.769, and when looking at AP(Average Precision) for each object, traffic accidents were the highest at 0.904, and debris were the lowest at 0.629.

• The Mathematical Education
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• v.63 no.1
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• pp.35-61
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• 2024

The purpose of this study is to examine changes in Korean middle school students' affective attitudes toward mathematics over the past 5 cycles of TIMSS. To this end, we first analyzed the changes in students' affective attitudes towards mathematics in five major countries, and then analyzed the changes in Korean students' affective attitudes toward mathematics by item. As a result of the study, there were positive changes in Korean students' interest, confidence, and value perception of mathematics during the recent 5 cycle of TIMSS. Korean male students' affective attitude toward mathematics is higher than that of female students, and the gender gap has been increasing recently. There was a large difference in the affective attitudes toward mathematics among Korean students, depending on their achievement level, and in particular, the affective attitudes toward mathematics of students at the lower achievement level remained significantly low. Item-level analysis revealed a decrease in Korean students' awareness of the necessity of mathematics in daily life. Based on these results, we discussed the implications for cultivating Korean students' affective attitudes. It is hoped that the results of this study will be meaningfully used as basic data for examining the performance of mathematics education in Korea and contribute to developing measures to foster students' positive attitudes toward mathematics.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.67-76
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• 2006

In this paper the moment transfer efficiency of a web and the strain concentration at the RHS (Rectangular Hollow Section) column-to-steel beam connections was evaluated. Initially, non-linear finite element analysis of five bare steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed that the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide Flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of the steel beam-to-column connections. Analytical results were compared with the previous experimental results. The analytical and the previous experimental results showed that the strain concentration was inversely proportional to the moment transfer efficiency of a beam web and the deformation capacity of connection was poor as their moment transfer efficiency degrades. Further finite element analyses of composite beam with a floor slab revealed that the neutral axis moved toward the top flange and the moment transfer efficiency of a beam web decreased, which led to premature failure of the connection.

• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.305-312
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• 2017

To evaluate the reliability of fly ash quality supplied to ready-mixed concrete plant using mass cylinder and hydrometer, in this research, the correlationship between the fly ash properties provided from certification and density measurement with suspension was evaluated. As a result, the reliability of the certification, except fineness and loss on ignition, all properties had a discord. Additionally, in the case of density, fineness, and L.O.I, the relation with the density measured using hydrometer showed high correlation, especially fineness was strongly related with the density measured using hydrometer. Furthermore, according to the comparative analysis with previous research, the fly ash used in this research was similar measurement with raw powder without any refining process, it is considered that the constant error of blaine test or using raw ash sample as a fly ash. In current standard regarding fly ash, the fineness range of class 2 can be changed from $3,000-4,500cm^2/g$ to $3,500-4,500cm^2/g$ for improved quality of fly ash in fineness aspect.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.189-199
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• 2015

Our country's leading granite weathered soil of the ground slope failures that occur in cutting slope most cases, it does not require in-depth to the shear strength most of the surface layer is affected by weathering (1~2 m) at a shallow depth close to the ground, it is important to identify the reliability. Based on the result obtained in actual field investigation, the field slope type was classified by each type of wedge slope, Infinite slope, finite slope -I and finite slope -II, and the slope stability was examined respectively. In addition, using the numerical analysis results, the relationship between the slope inclination angle and safety factor was analyzed and it tried to offer basic data to which the stability in the field slope was able to be estimated by analyzing the safety factor change of the slope according to the slope type. In this study, classified into four types of natural slope, safety factor estimation method by slope types is proposed through the numerical analysis. However, some limit exists in generalizing in this research because it does not test various case studies. Therefore, the case study of a wide range of various sypes to assess the safety of various types slope can be made, accommodate a wide range of field conditions reasonable risk evaluation criteria may be derived.