This study examined the determinants of healthy food purchases before and after COVID-19 in Korea. Binomial and multinomial logistic regression models were applied to Korea Rural Economic Institute's Food Consumer Behavior Survey data from 2019 to 2021. The analysis revealed a significant decrease in the non-intake of healthy food in 2021 compared to 2019, suggesting the impact of COVID-19 on healthy food consumption. Consumption patterns also changed, with a decrease in direct purchases and an increase in gift-based purchases. Several variables showed significant effects on healthy food intake. Single-person households exhibited a higher probability of eating healthy food after COVID-19. The group perceiving themselves as healthy had a lower likelihood of consuming healthy food pre-COVID-19, but this changed after the pandemic. Online food purchases, eco-friendly food purchases, and nut consumption showed a gradual decrease in the probability of non-intake over time. Gender and age also influenced healthy food intake. The probability of eating healthy food increased in the older age group compared to the younger group, and the probability increased significantly after COVID-19. The probability of buying gifts was significantly higher in those in their 60s, indicating that the path to obtaining healthy food differed by age.

We performed a study to examine the association between diet quality and nonalcoholic fatty liver disease (NAFLD). Our study included 3,586 women aged 40-64 years who participated in the sixth Korea National Health and Nutrition Examination Survey. The study subjects were classified into the NAFLD group (n=816) and the normal group (n=2,770) using the hepatic steatosis index. The anthropometric indices, blood profiles, and dietary intake data of the subjects were obtained. The waist circumference, body mass index, and the serum levels of triglycerides, fasting blood sugar, HbA1c, and systolic and diastolic blood pressures were higher in the NAFLD compared to the normal groups (p<0.001, respectively). The intakes of protein (g/kg body weight, p<0.001), potassium (p<0.001), and vitamin A (p=0.006) were significantly lower in the NAFLD group. It was observed that the higher the total Korean Healthy Eating Index score, the lower the risk of NAFLD. A reverse relationship was shown between the NAFLD risk and the intakes of total fruits, total vegetables, vegetables excluding Kimchi and pickled vegetables, meat, fish, eggs and beans. Therefore, it is recommended that middleaged women in Korea increase their intakes of fruits, vegetables, and foods high in protein for the proper management of NAFLD.

The labor environment in Korea has changed and problems related to employment types are treated as important issues. Especially, the ratio of irregular workers has not only increased relatively, but the labor conditions in Korea also have worsened in the current years. Studies have reported an association between temporary workers and the prevalence of diseases. However, there is insufficient research on chronic disease and employment types. Methods: The current study examines the prevalence rate of diseases and health behavior by categorizing employment types among Korean adults. Data were obtained from the 2016-2018 Korea National Health and Nutrition Examination Survey. Totally, the data of 2,366 workers (1,239 regular and 1,127 irregular) were analyzed in the study. The types of employment were classified by a questionnaire querying about working conditions. The results showed that irregular workers earned less than regular workers and had a significantly higher prevalence of diabetes mellitus and hypertension. We propose that if discrimination related to working conditions were relieved, irregular workers would be able to invest more time to exercise and doing check-ups regularly. In addition, individual nutrition consultations considering the knowledge and personal environmental factors of each individual are necessary for the improved health of all workers.

In this study, we aimed to explore whether eating alone is associated with mental health conditions in Korean adolescents. The data of 2,012 Korean adolescents aged 12-18 years were obtained from the Korea National Health and Nutrition Examination Survey 2015–2019. Participants were classified into three groups based on the frequency of eating alone: none (all meals with others); 1 meal/day alone; and 2 meals/day alone. Mental health conditions were assessed based on stress recognition, depressive symptoms, and suicidal ideation. Multivariable logistic regressions were employed to calculate the adjusted odds ratios (AORs) and 95% confidence intervals (CIs) of poor mental health conditions according to the frequency of eating alone. Adolescents who ate 2 meals/day alone had higher odds of stress recognition (AOR: 2.65, 95% CI: 1.94- 3.63), depressive symptoms (AOR: 2.55, 95% CI: 1.47-4.42), and suicidal ideation (AOR: 2.53, 95% CI: 1.05-6.08) than those who ate all their meals with others. In addition, having breakfast or dinner alone increased the odds of stress recognition. Considering the continuous increase in the social phenomenon of eating alone, nutritional educations are needed to develop adolescents' ability to choose more nutritionally balanced and healthy meals when eating alone.

This study investigates the effect of the DDL (Data-Driven Learning) approach on the English sentence writing ability of 6th graders in elementary school. To this end, a total of seven English textbooks were used to build a corpus. Five teachers were then asked to conduct five lessons using a weak version of DDL in their 6-grade EFL classrooms. Students were asked to complete a pre- and post-test and a pre- and post-survey, and a selected number of students and four of the five teachers had in-depth interviews with the researcher. The results are as follows: First, DDL using the textbook corpus was found to be adequate for helping elementary students improve their sentence-writing ability. Second, DDL had a significant effect on upper, middle, and lower level groups of students. Third, the students felt that DDL was neither unfamiliar nor difficult. Fourth, teachers with little teaching experience found it easy to conduct their classes using the DDL approach. This study implies that DDL is an effective approach to teaching communicative functions and language forms in the elementary English classroom and can be useful for all levels of elementary students.

지구의 기후 변화를 유도하고 제어하는 가장 중요한 역할을 하는 것은 해양의 해류이다. 황해는 수심이 동해 에 비해 매우 얕고, 다양한 바람과 조류, 강물의 유입, 동중국해에서의 해수 유입 등 외력의 영향으로 해수의 순환과 해류가 상당히 복잡하다. 황해난류는 겨울철 황해의 대표적인 해류로서 겨울철 황해와 동중국해 바람 변동성과 밀접한 관련이 있으며, 황해의 수온과 염분 분포에 큰 영향을 주어서 중등학교 교과서에서 중요하게 다루어질 필요성이 있다. 2015 개정 교육과정 기반 중등학교 과학 및 지구과학 교과서의 황해난류와 관련된 내용을 분석하였다. 또한 해류의 시 간 변동성에 대한 교사들의 인식을 조사하기 위해 중등학교 과학 교사들을 대상으로 설문조사를 실시하였다. 대부분의 교사들은 황해난류가 우리나라 서해안으로 연중 북상하고 있으며 일반적인 난류와 같이 여름철에 강하다는 잘못된 지 식을 가지고 있는 것으로 나타났다. 황해난류는 해류의 세기가 강한 계절변동성을 가지는 북한한류와 달리 해류 자체가 연중 항시 존재하지 않으며 겨울철에만 발생하는 해류이다. 이러한 교사들의 교과내용 지식에 대한 오류는 북한한류가 겨울철에 강하다는 오개념을 가지게 된 연유와 유사한 배경을 가지고 있었다. 따라서 본 연구에서는 황해난류에 대한 교과서 내용의 오류를 분석하여 제시하였다. 또한 학생들과 교사들의 데이터 리터러시 함양을 위하여 탐구활동에서 활 용할 수 있는 황해난류에 대한 수업 자료를 개발하였다. 황해 해수면 온도를 가시화할 수 있는 GUI 프로그램을 소개하 였고, WOA (World Ocean Atlas) 2018 해양 실측 수온 및 염분자료와 국립해양조사원에서 생성한 해양 수치모델 재분 석자료를 활용하여 수온과 염분의 공간 분포를 도시하는 자료를 개발하여 제시하였다. 이러한 해양 자료를 활용한 데이 터 시각화과정은 교사들의 오개념을 개선하고, 나아가 학생들과 교사들의 해양 리터러시뿐만 아니라 데이터 리터러시도 제고하는 계기가 될 것으로 기대된다.

PURPOSES : The initial smoothness of concrete pavement surfaces must be secured to ensure better driving performance and user comfort. The roughness was measured after hardening the concrete pavement in Korea. When the initial roughness is poor, relatively large-scale repair works, such as milling or reconstruction must be performed. Hence, a method to measure the roughness of the concrete pavements in realtime during construction and immediately correct the abnormal roughness was developed in this study. METHODS : The profile of a concrete pavement section was measured at a construction site using sensors that were attached to the tinning equipment of the paver. The measured data included outliers and noise caused by the sensor and vibration of the paving equipment, respectively, which were further calibrated. Consequently, the calibrated data were input into the ProVAL program to calculate the roughness based on the international roughness index (IRI). Additionally, the profile of the section was re-measured using another method to verify the reliability of the calculated IRI. RESULTS : The profile data measured at the concrete pavement construction site were calibrated using methods, such as overlapped boxplot outlier removal and low-pass filtering. The outlier data from the global positioning system (GPS), which was installed to identify the construction distance, was also calibrated. The IRI was calculated using the ProVAL program by matching the measured profile and GPS data, and applying the moving average method. The calculated IRI was compared to that measured using another method, and the difference was within the tolerance. CONCLUSIONS : A method to measure the roughness of the concrete pavements in real time during construction was developed in this study. Hence, the performance of concrete pavements can be improved by enhancing the roughness of the pavement considerably using the aforementioned method.

This study investigated the potential role of dietary factors associated with obesity and metabolic syndrome (MetS) in Koreans. The scoping review method was used to evaluate the studies that utilized the secondary data sets comprising the Korean National Health and Nutrition Examination Survey (KNHANES) and the Korean Genome and Epidemiology Study (KoGES). Articles published between 2012 and 2022 were identified using RISS, KISS, DBpia, PubMed, and ScienceDirect databases. In all, there were 32 published articles on obesity and 119 on MetS. Obesity research included eight articles on nutrients, 12 on food items/food groups, two on dietary patterns, nine on dietary behavior/eating habits, and one on the dietary index. MetS studies comprised 34 articles on nutrients, 43 on food items/food groups, seven on dietary patterns, 25 on dietary behavior/eating habits, and 10 on the dietary index. Carbohydrates, alcohol, and coffee consumption were the most frequently studied dietary factors for obesity and MetS. The primary areas of study were largely focused on nutrients and food items/food groups. Thus, to overcome the paucity of information on the relationship of dietary patterns and dietary indexes with obesity and MetS, there is a need for further research using the KNHANES and KoGES data sets.

PURPOSES : The purpose of this study was to select recurring congested sections through an objective and reasonable method using intelligent transportation system (ITS) collection data as the first phase for controlling recurring congested sections. The selection is meant to enhance the utilization of national highway ITS collection data that are just managed as statistical data focusing on real-time traffic information or not satisfactorily used. METHODS : Hourly statistical data were obtained using travel speed with a 5-min frequency per information-providing section stored in the database server. The travel speed data were collected from field equipment in general national highway sections (793.8 km in 380 sections of 16 lines in 2017) in the Seoul Metropolitan Area through a literature review of congestion standards. Subsequently, the congested sections were drawn by dividing a month into weekdays and weekends, and the status of the monthly change and characteristics of the congested sections were analyzed. Based on the monthly data on the congested sections, monthly mean congested days and hours were calculated to select the significant recurring congested sections in 2017 and applied to the congestion frequency standard. RESULTS : Recurring congested sections occurred in seven sections (33.9 km) in three lines — in five sections (24.8 km) of two lines during the weekdays and in two sections (9.1 km) of one line during the weekends. The recurring congested sections selected based on the congested days and the recurring congested sections selected based on the congested hours were found to be the same. The recurring congested sections during the weekdays and weekends were not mutually duplicated and were divided. More congestion occurred during the weekdays than on weekends. CONCLUSIONS : In the seven sections selected as recurring congested sections, congestion occurred for more than six months during one year, indicating that congestion is concentrated in specific months, albeit continuously and repeatedly occurring over the long term. The recurring congestion section selection standard and method used in this study are considered to be objective and reasonable. If recurring congested sections are selected using the standard and method presented in this study using ITS collection data targeting general national highways nationwide in the Seoul Metropolitan Area, it is necessary to determine whether the standard and method reflect actual congestion situations satisfactorily. According to the result, a further study considering congestion speed and congestion frequency standards is needed.

In order to determine fragility curves, the limit state of piers for each damage level is suggested in this paper based on the previous test results in Korea, including our test results. In previous studies, the quantitative measures for damage levels of piers have been represented by curvature ductility, lateral drift ratio, or displacement ductility. These measures are transformed to lateral drift ratios of piers for consistency, and the transformed values are compared and verified with our push-over test results for flexural RC piers with a circular cross-section. The test specimens are categorized concerning the number of lap-splices in the plastic hinge region and whether seismic design codes are satisfied or not. Based on the collected test results in Korea, including ours, the lateral drift ratio for each pier damage level is suggested.

낙동강 하구 기수생태 복원이 본격으로 논의가 진행 전인 2016년까지는 하류 수위의 예측을 위해 하구에서 수km 떨어진 기존 조위관측소(부산 및 가덕도)의 측정 자료를 활용하여 분석을 수행하였지만, 조위와 위상 차이로 인해 예측이 용이하지 않았다. 따라서, 낙 동강 하굿둑 인접 외해역에서 조석 영향을 받는 수위관측치를 이용하여 조석조화분해를 통한 정밀한 조위 예측 산정의 필요성이 대두되 어 본 연구를 수행하였다. 연구의 방법으로는 낙동강하굿둑 인근 외해역에서 10분 간격으로 기간별 관측자료의 저장상태 및 이상자료 유 무를 확인하고, 조석조화분해 프로그램인 TASK2000(Tidal Analysis Software Kit) Package를 이용하여 관측조위와 예측조위를 1대 1 비교하여 회귀상관분석을 수행하였다. 분석 결과, 관측조위와 예측조위간의 상관도는 0.9334로 높게 나타났으며, 당해 연도의 조위예측 분석시 직전 연도의 1년 조석관측 자료를 조화분해하여 산출된 조화상수를 이용하여 조위예측을 실시하면 보다 정확한 결과를 산출할 수 있음을 확인 하였다. 이를 바탕으로 2022년 예측조위를 생성하여 낙동강 하구 기수생태 복원의 해수유입량의 산정에 활용 중이다.

This study investigated the association between dietary intake and 10-year risk for CHD predicted from Framingham risk score in Korean adults using the Korea National Health and Nutrition Examination Survey 2019-2020. Eight thousand subjects (3,382 men and 4,618 women) aged 30 years or older were classified into three groups according to the 10-year CHD risk (%). The sociodemographics, anthropometrics indices, blood profiles, and dietary intake were collected. After adjusting for confounding variables, the mean adequacy ratio (MAR) decreased for both men and women as the disease risk increased. The high–risk group was below the MAR criteria, indicating that the overall quality of the meal was not good. The highest consumers of legumes (OR 0.56, 95% CI 0.37-0.84), fruits (OR 0.67, 95% CI 0.48-0.93), and fish (OR 0.60, 95% CI 0.42-0.87) had a 44%, 33%, and 40% lower 10-year CHD risk than lowest consumers in men, respectively. In women, there is no significant relationship between food groups and disease risk. Therefore, improving lifestyle habits such as weight control, increased activity, and adequate food intake, especially legumes, fruits, and fish rich in antioxidant nutrients and bioactive substances, appears to have a potential association with preventing coronary heart disease in Korean adults.

본 연구에서는 칠발도, 거문도, 동해에서 20년 이상 관측된 파랑자료를 16 방위별 극치확률분석을 통해 재현빈도별 심해설 계파를 산정하였고, 이 값을 방향을 고려하지 않은 전방향파의 심해설계파와 비교하였다. Weibull 분포함수를 확률분포함수로 사용하였 으며, 최소자승법을 사용해서 매개변수를 결정하였다. 추정된 분포함수는 Kolmogorov-Smirnov 방법을 사용하여 적합도를 검증하였다. 그 결과 방향별로 구한 심해설계파가 전방향파의 심해설계파보다 모든 방향에서 상대적으로 작은 것으로 나타났다. 파향별로 구한 50년 빈도 설계파고는 칠발도, 거문도, 동해에서 각각 7.46 m(NNE), 12.05 m(S), 9.69 m(SSW)가 최대값이지만, 전방향파로 구한 설계파고는 각각 7.91 m, 13.82 m, 10.38 m이었다. 이는 현재 해양 및 연안 구조물 설계에 사용하고 있는 16 방위별 심해설계파고가 과소산정되었을 가능 성이 있음을 보여준다.

The prediction of algal bloom is an important field of study in algal bloom management, and chlorophyll-a concentration(Chl-a) is commonly used to represent the status of algal bloom. In, recent years advanced machine learning algorithms are increasingly used for the prediction of algal bloom. In this study, XGBoost(XGB), an ensemble machine learning algorithm, was used to develop a model to predict Chl-a in a reservoir. The daily observation of water quality data and climate data was used for the training and testing of the model. In the first step of the study, the input variables were clustered into two groups(low and high value groups) based on the observed value of water temperature(TEMP), total organic carbon concentration(TOC), total nitrogen concentration(TN) and total phosphorus concentration(TP). For each of the four water quality items, two XGB models were developed using only the data in each clustered group(Model 1). The results were compared to the prediction of an XGB model developed by using the entire data before clustering(Model 2). The model performance was evaluated using three indices including root mean squared error-observation standard deviation ratio(RSR). The model performance was improved using Model 1 for TEMP, TN, TP as the RSR of each model was 0.503, 0.477 and 0.493, respectively, while the RSR of Model 2 was 0.521. On the other hand, Model 2 shows better performance than Model 1 for TOC, where the RSR was 0.532. Explainable artificial intelligence(XAI) is an ongoing field of research in machine learning study. Shapley value analysis, a novel XAI algorithm, was also used for the quantitative interpretation of the XGB model performance developed in this study.

This study investigated the methods of effectively removing noises in the acoustic data collected from the cold water zone of the East Sea, and converted that data into NASC values for comparison and analysis. First, the noises accompanying the acoustic data were divided into background noise, impulse noise, transient noise and attenuated signals according to the pattern characteristics. Then, the NASC values before and after noise removal were compared. As a result, the background noises were found to show the highest difference of 6,946 times in the NASC values before and after removal. The attenuated signals showed that the NASC values were higher after the removal.

본 연구는 산림자원으로 활용 가능한 활엽수림(혼효림 포함)의 상층 교목성 수종을 대상으로 유사한 수종구성을 갖는 산림 유형 분류를 통해 활엽수림의 효율적 산림관리 기반 구축을 위해 실시하였다. 제7차 국가산림자원조사 고정표본점(3,994지점) 중 2,291지점의 임분 현황 자료를 기반으로 클러스터분석, 지표종분석, 다중판별분석 등 다양한 다변량 통계분석 기법을 이용하여 산림 유형을 분류하였다. 활엽수림의 산림 유형은 신갈나무-피나무림, 신갈나무-당단풍나무림, 신갈나무-물푸레나무림, 신갈나무-굴참나무림, 신갈나무-소나무림, 졸참나무-굴참나무림, 소나무-신갈나 무림, 소나무-굴참나무림, 밤나무-아까시나무림, 상수리나무-소나무림 등 10개로 구분되었다. 신갈나무와 기타 활엽수림, 신갈나무가 우점하는 참나무 림, 주요 참나무류 수종과 소나무의 혼효림 형태로 구성된 것으로 파악되었다. 조사된 102종의 수종 중 점유비율이 높은 신갈나무, 굴참나무 및 소나무가 산림유형 분류에 중요한 역할을 한 것으로 나타났다.

PURPOSES : A methodology for estimating micro-emission factors using vehicle trajectory data collected from navigation and DTG devices and basic emission factors for each vehicle type of the MOtor Vehicle Emission Simulator (MOVES) is presented. The methodology can calculate micro-emissions based on only the traffic volume and average speed for each vehicle type. METHODS : Cluster analysis was performed by accumulating the trajectories of individual vehicles on a specific road section into speed groups in which vehicles drove with the same range of average speed. Then, the micro-emission factors were estimated for each speed group. RESULTS : Using the vehicle trajectory data revealed that the emissions calculated from micro-emission factors estimated by the proposed methodology were similar to the sum of the emissions calculated from the vehicle trajectories for each vehicle. CONCLUSIONS : The micro-emission factor database for each road type and vehicle type proposed in this study should be useful for estimating vehicle emissions on the road. The proposed method can calculate emissions in the same way as the macroscopic analysis method, using the traffic volume, average speed, and link length.