Earticle

본 연구는 목조문화재 흰개미 피해와 기상데이터를 이용하여 기계학습 모형을 수립하고 예측 성능을 평가하였다. 데이터는 흰개미 피해 데이터, 목조문화재 위치, 기상데이터로 구 분하였으며, 목조문화재 위치를 기준으로 가까운 3개의 관측지점을 탐색하고, 2010년부터 2018 년까지 약 8년의 기상데이터를 종합하여 총 491개의 데이터 셋을 만들었다. 정제된 데이터 셋 을 이용하여 기계학습 모형을 만들어 평가한 결과, 흰개미 피해에 직접적인 영향을 미치는 기 상요인으로 소형증발량이 모형을 가장 잘 설명해주는 시계열 독립변수라는 것을 확인하였으 며, Linear SVM 알고리즘 모형을 이용하였을 때 72.8%의 정확도를 나타내었다. 소형증발량은 기상청 종관기상 데이터로 모든 관측소에서 관측되는 기상요인이 아니라 특정 관측소에서만 수집되고 있어 예측 모형을 만들기에 충분한 데이터 확보가 어렵다. 기계학습 모형은 데이터수 가 충분할 때 정확도를 높일 수 있기 때문에 흰개미 피해 데이터와 소형증발량 데이터가 더 확보된다면 예측 성능을 높일 수 있을 것이다.

In this study, a machine learning model was established using termite damage and meteorological data on wooden cultural properties, and the prediction performance was evaluated. The data were divided into termite damage data, the location of wooden cultural properties, and meteorological data. Three observatories were searched based on the location of the wooden cultural properties, and meteorological data for about 8 years from 2010 to 2018 were combined to make a total of 491 data sets. As a result, it was confirmed that the value of small evaporation as a meteorological factor that directly affects termite damage is the time series independent variable that best explains the model, and showed an accuracy of 72.8% when the Linear SVM algorithm model was used. The value of small evaporation is the synoptic meteorological data of the Korea Meteorological Administration, and it is collected only at specific stations, not meteorological factors observed at all stations. Therefore, It is difficult to obtain enough data to make a predictive model. Since machine learning models can improve accuracy when the number of data is sufficient, prediction performance can be improved if more termite damage data and the value of small evaporation are obtained.

Purpose: This study aimed to develop a machine learning (ML)-based predictive model for hospitallength of stay incorporating clinical, nursing, and healthcare system factors to optimize hospitalresource allocation, improve patient-centered care, and enhance nursing workflow efficiency. Methods: This retrospective study analyzed a large dataset of inpatient electronic medical records froma private tertiary hospital. The dataset was used to develop predictive models for long-term versusshort-term hospitalization. The modeling process involved several ML algorithms, and their performancewas evaluated using standard statistical metrics. The most significant predictive variables wereidentified through an analysis of their feature importance. Results: Among the tested models, the Random Forest algorithm exhibited the highest predictive accuracy,demonstrating strong performance in predicting hospital length of stay. Key influencing factorsincluded the number of consultations, postoperative recovery time, duration of stay in the intensive careunit, the use of third-generation antibiotics, and the need for infection isolation. Patients requiringventilator care, intensive care unit admission, and specific powerful antibiotics were more likely toexperience prolonged hospitalization. Additionally, nursing-related factors such as fall risk and pressureulcer risk were significantly correlated with an extended hospital stay. Conclusion: This study demonstrates that ML models can effectively predict hospital length of stay,aiding in hospital resource management, nursing workforce allocation, and patient safety interventions. The integration of predictive analytics into healthcare systems can support early risk assessment,personalized discharge planning, and overall hospital efficiency.

Purpose: The purposes of this study were to develop a prediction model for pressure injury using a machine learning algorithm and to integrate it into clinical practice. Methods: This was a retrospective study of tertiary hospitals in Seoul, Korea. It analyzed patients in 12 departments where many pressure injuries occurred, including 8 general wards and 4 intensive care units from January 2018 to May 2022. In total, 182 variables were included in the model development. A pressure injury prediction model was developed using the gradient boosting algorithm, logistic regression, and decision tree methods, and it was compared to the Braden scale. Results: Among the 1,389,660 general ward cases, there were 451 cases of pressure injuries, and among 139,897 intensive care unit cases, there were 297 cases of pressure injuries. Among the tested prediction models, the gradient boosting algorithm showed the highest predictive performance. The area under the receiver operating characteristic curve of the gradient boosting algorithm's pressure injury prediction model in the general ward and intensive care unit was 0.86 (95% confidence interval, 0.83~0.89) and 0.83 (95% confidence interval, 0.79~0.87), respectively. This model was integrated into the electronic health record system to show each patient's probability for pressure injury occurrence, and the risk factors calculated every hour. Conclusion: The prediction model developed using the gradient boosting algorithm exhibited higher performance than the Braden scale. A clinical decision support system that automatically assesses pressure injury risk allows nurses to focus on patients at high risk for pressure injuries without increasing their workload.

Purpose: This study aimed to develop a predictive model for the early identification of patients at risk of sepsis, using routinely available clinical information and laboratory test results collected during the initial phase of patient care. Methods: This retrospective analysis included electronic medical records of 22,400 adult patients who presented with suspected infection to a tertiary care university hospital in Korea between January 2013 and May 2024. Patients were classified according to Systemic Inflammatory Response Syndrome (score ≥ 2) or Quick Sequential Organ Failure Assessment (score ≥ 2), in combination with sepsis-related International Classification of Diseases, 10th revision codes. Four different machine learning models were trained and validated using five-fold cross-validation. In addition, Shapley additive explanations analysis was performed to interpret the contribution and clinical relevance of key predictive variables. Results: Among the evaluated models, CatBoost demonstrated the strongest predictive performance. Notably, platelet distribution width, alveolar?arterial oxygen difference, procalcitonin, and the arterial/alveolar oxygen ratio consistently emerged as major predictors. Importantly, several variables that did not reach statistical significance in univariate analysis nevertheless contributed substantially to overall model performance, highlighting the importance of complex, multidimensional interactions among clinical factors. Conclusion: These findings indicate that a model based on simple, routinely collected clinical data can achieve high predictive accuracy and strong generalizability. Such a tool may support early clinical decision-making by multidisciplinary teams, including nurses, across diverse real-world care settings. Further prospective studies are warranted to validate its clinical utility and to assess its potential effects on patient outcomes.

Objective To present new classification methods of knee osteoarthritis (KOA) using machine learning and compare its performance with conventional statistical methods as classification techniques using machine learning have recently been developed. Methods A total of 84 KOA patients and 97 normal participants were recruited. KOA patients were clustered into three groups according to the Kellgren-Lawrence (K-L) grading system. All subjects completed gait trials under the same experimental conditions. Machine learning-based classification using the support vector machine (SVM) classifier was performed to classify KOA patients and the severity of KOA. Logistic regression analysis was also performed to compare the results in classifying KOA patients with machine learning method. Results In the classification between KOA patients and normal subjects, the accuracy of classification was higher in machine learning method than in logistic regression analysis. In the classification of KOA severity, accuracy was enhanced through the feature selection process in the machine learning method. The most significant gait feature for classification was flexion and extension of the knee in the swing phase in the machine learning method. Conclusion The machine learning method is thought to be a new approach to complement conventional logistic regression analysis in the classification of KOA patients. It can be clinically used for diagnosis and gait correction of KOA patients.

당뇨병은 혈당 수치가 오랜 시간 지속되는 대사질환이다. 당뇨병은 자체 질환에 대한 위험성과 더불어 심혈관과 뇌혈 관, 망막병증, 족부병변 등 질환 다양한 합병증을 유발하는 질병이다. 이렇게 발생하는 합병증으로 인해 사망률을 높이는 원인이 되고 있다. 이에 따라 당뇨병 조기발견과 합병증에 대한 치료가 수반되어야하며, 이를 위해 빠른 진단이 필요하 다. 이에 본 연구에서는 당뇨병 환자 데이터를 이용하여 인공지능 기법 중 로지스틱 회귀분석 머신러닝 알고리즘을 이용한 당뇨병 분류에 대한 머신러닝 모델을 구축하고자 한다. 머신러닝 모델은 scikit-learn을 이용하여 학습용 데이터 80%, 검증용 데이터 20%로 구분하고 교차검증을 5로 나누어 모델을 구성하였다. 로지스틱 회귀분석을 이용한 머신러닝 결과 정확도는 평균 92.24%, AUC 0.95, Recall 0.9294, Precision 0.927, F1 score 0.9248, Kappa 0.6983 이었으 며, 허리-엉덩이 둘레비율이 당뇨병 분류에 가장 큰 영향을 주는 변수였다. 간단한 모델을 통해 높은 성능의 모델을 구축할 수 있었으며, 개인 생활습관 등에 관한 변수를 추가한다면, 더욱 우수한 성능의 머신러닝 모델을 구축할 수 있을 것으로 사료된다.

Diabetes is a metabolic disease in which blood sugar levels last for a long time. Diabetes is a disease that causes various complications of diseases such as cardiovascular and cerebrovascular, retinopathy, and diabetes foot ulcer in addition to the risk of its own disease. Complications that occur in this way are responsible for increasing the mortality rate. Accordingly, early detection of diabetes and treatment for complications should be accompanied, and for this, rapid diagnosis is required. In this study intends to build a machine learning model for diabetes classification using logistic regression machine learning algorithm among artificial intelligence techniques using diabetes patient data. Machine learning model was divided into 80% of training data and 20% of verification data using scikit-learn, and the cross-validation was divided into 5 to construct a model. Accuracy of machine learning results using logistic regression analysis was 92.24% on average, AUC 0.95, Recall 0.9294, Precision 0.927, F1 score 0.9248, and Kappa 0.6983, and the waist-hip circumference ratio was the most influential variable for diabetes classification. A high-performance model could be built through a simple model, and if variables related to personal lifestyle are added, it is believed that a better performance machine learning model can be built.

Accuracy improvement of classification model becomes main research objective in various fields. Selecting important features and removing outliers of a dataset are two effective solutions for improving model accuracy. Information Gain is one of the feature selection methods that can be considered as a solution for selecting important features of a dataset. Information Gain selects the variable that maximizes the information gain, which in turn minimizes the entropy and best splits the dataset into groups for effective classification. Aside of selecting important feature, removing outlier is also necessary for improving accuracy of the classification model. Density-Based Spatial Clustering of Applications with Noise (DBSCAN) is one of the powerful outlier removal methods which can identify with significant accuracy the clusters of random shape and size in large databases corrupted with noise. Therefore, in this study, we propose the accuracy improvement of heart disease classification model using Information Gain and DBSCAN applied to various machine learning algorithms. One publicly available heart disease dataset (Cleveland) is utilized in this study to build the classification model. The results showed that after implementing Information Gain, the accuracy of the model applied to Gaussian Naïve Bayes, Logistic Regression, Multi-Layer Perceptron, Support Vector Machine, Decision Tree, Random Forest, and Extreme Gradient Boosting algorithms increases as much as 1.31% in average. The accuracy also increases when DBSCAN is applied to the model after utilizing Information Gain, with the number of improvements is around 0.62%.

Heart disease is a major cause of mortality in the world that is in dire need of accurate, interpretable predictive measures that could be utilized to manage it proactively. The writer of this paper proposes an Explainable AI (XAI) Ensemble Machine Learning model to predict heart disease using an 1,025 patient record dataset. To achieve methodological rigor and generalization, 5- Fold Stratified Cross-Validation (CV) was used to evaluate all models, such as LightGBM and Random Forest. LightGBM model was stable and better in performance as it had Mean CV Accuracy of ±0.9620 ±0.0178. Integration of XAI (SHAP/LIME) is the means of creating clinical trust; analysis has confirmed maximum heart rate (thalach) and type of chest pain (cp) as medically significant characteristics. This framework supports the sustainable smart city healthcare through a highly transparent decision-support system, which manages the resources in optimizing scalable public health programs.

In 2022, the Korean government announced its intention to join the CPTPP, led by Japan and launched in 2018, which aims to achieve comprehensive tariff abolition and establish new trade norms. According to our analysis, as with traditional gravity model outcomes, it appears that the greater the per capita GDP and the shorter the distance between countries, the greater the effect on promoting trade. However, the trade-enhancing effect after the enforcement of the CPTPP has not yet been clearly confirmed. Nevertheless, if tariff abolition and reduction proceed as planned, the trade-enhancing effect of the CPTPP is expected to gradually expand. On the other hand, an increase in trade between Japan and CPTPP member countries may suggest a potential contraction in trade with non-member countries. This could pose a threat to Korean industries that need to establish a stable supply chain within the Asia-Pacific region. As Japan is South Korea's fourth largest trading partner, a detailed review of the impact of the CPTPP on future trade between Japan and its member countries should form the basis for discussions on Korea's possible participation in the CPTPP and the content of negotiations.

토양수분은 가뭄 발생과 해소를 매개하는 핵심 인자로서, 대기-지표-지하수로 이어지는 수문순환의 연결 고리 역할을 한다. 이처럼 가뭄 연구 및 분석을 위한 토양수분 자료 관측 센서를 설치하여 측정하고 있으나, 기상 및 통신 장애로 결측이 발생하여 자료 활용에 불편함을 겪고 있다. 본 연구에서는 해남·예산 지역에 설치된 토양수분 모니터링 시스템의 토양수분 결측 자료를 보간하기 위하여 먼저 강수 자료를 보간하고, 강수 특징변수로 머신러닝의 학습자료를 5개로 구축하여 학습 및 평가자료 정확도 결과를 비교·분석하였다. 연구 결과, 지연, 누적, 시계열 특징변수로 구성한 D, E 학습자료 기반 머신러닝 모형이 훈련·검증자료 정확도가 우수하였다. 평가자료 정확도는 D, E 학습자료 기반 XGB 모형이 우수하였으나, E 학습자료 기반 XGB 모형은 다른 조합 대비 더 많은 경우에서 우수한 정확도를 보였다. 따라서 E 학습자료 기반 XGB 모형을 활용하여 해남·예산 지역에 설치된 토양수분 모니터링 시스템의 10·20cm 깊이 토양수분 결측 자료를 보간하는게 적절하다고 판단하였다.

Soil moisture is a key variable governing drought onset and recovery and a critical link in the hydrological cycle connecting the atmosphere, land surface, and groundwater. Missing observations frequently occur in soil moisture monitoring systems due to meteorological and communication failures, limiting data usability. In this study, missing soil moisture data from monitoring systems in Haenam and Yesan were gap-filled by first correcting precipitation data and constructing five machine-learning training datasets using precipitation-based features. Model performance was evaluated using training, validation, and evaluation datasets. Results indicate that Training D and E datasets, incorporating lagged, accumulated, and time-series precipitation features, combined with the XGB algorithm, showed superior performance. The D– and E–XGB combinations also achieved high accuracy in the evaluation dataset, with the E–XGB model outperforming others in more cases. Therefore, the E-dataset XGB model is suitable for gap-filling 10- and 20-cm soil moisture data in the Haenam and Yesan regions.

This study investigates the use of machine learning techniques to estimate the value of studio apartments (Officetel), which are increasingly important as combined office and residential spaces for single-person households and freelancers. It aims to identify key variables affecting studio apartment prices and preprocess them for accurate predictions. Transaction data from studio apartments are used to compare the predictive performance of four methods: Multiple Regression Analysis, Random Forest, XG Boosting, and Deep Learning. The study seeks to determine the best-performing models for price estimation and aims to develop predictive models applicable to various real estate types and regions.

Although there have been studies using various algorithms on the delivery time prediction in the logistics business, those studies did not reflect various features such as region or product. In the case of delivery time prediction of a single model that does not reflect the features, the accuracy of delivery time prediction for a region with a high distribution is high, but the prediction accuracy is low for a region with a low distribution. To solve this problem, this paper proposes a method of classifying logistic patterns using clustering and selecting an optimal model for each logistic pattern. The proposed method consists of four steps. First, the derived variables such as reception day, delivery speed and delivery distance are created. Second, the data with the same pattern goes through clustering using K-means. Third, by comparing the performance of each model using six regression algorithms for each classified logistic pattern, an optimal model is selected and the model is stored. Lastly, the logistic pattern of the data to be predicted is classified and the optimal model stored for each pattern is loaded, and the result of delivery time prediction is provided through the model. Two experiments were performed to verify the proposed method. The e-commerce data from Brazil is used as verification data. From the experiment, the delivery time prediction error of the proposed model was smaller than that of the single regression model.

In this study, AAHT was estimated using machine learning algorithms of ensemble techniques to improve the limitations of existing studies. Among the machine learning algorithms, a random forest algorithm was used, and the traffic volume estimation accuracy was analyzed as MAPE 20.7%. It was analyzed that the higher the traffic volume level, the higher the traffic volume estimation accuracy, and the traffic volume level of 3,000 vehicles/hour or more was analyzed to be 8% or less of MAPE. It was analyzed that the accuracy secured at the current level was very high compared to the existing model.

Understanding an accurate trip demand by purpose is crucial for short-term regional planning but also long-term regional planning. In traditional approach, information of purpose-oriented trip demand has been derived from public survey in South Korea such as Travel Diary Survey. This type of data acquiring method maybe useful in a sense that it can capture a meaningful sample regarding to entire country, meanwhile it costs a tremendous amount of budget and time. In this research, we want to offer a novel framework for estimating purposeoriented trip demand with dynamic and effective fashions using data fusion in conjunction with Machine learning techniques. With primary results of this concept, this study showed how several state-of-the-art algorithms, including Deep neural network, UMAP, and random forest in conjunction with Genetic algorithm and Tabu-search for optimization, can contribute to this framework. Although tangible results are yet to come, we expect this framework can contribute to resilience planning such as COVID-19.

Predicting traffic accidents is a challenging task because taking into account uncertainty in modeling traffic accidents is not trivial. To address these issues, this article develops a hybrid modeling pipeline combining unsupervised and supervised learning to predict the level of hazardous road sites and explore the causality of accidents by controlling unobserved heterogeneity issues effectively. Traffic accident data for Won-ju province, Korea, from 2020 to 2021, and external factors affecting traffic accidents, such as average travel speed and weather information, are combined based on road links. Through the modeling pipeline, a clustering technique is adopted to capture unobserved heterogeneous information among roads. Since traffic accident data contains a wide variety of categorical and hierarchical features, ensemble methods such as boosting techniques were applied to handle heterogeneity issues among these features. To explore the relationship between the accident and determinant factors, are adopted to interpret the results of machine learning models. Model-agnostic methods, however, generally provide results based on images, this study also added a process that extracts texts from images to overcome compatible issues with existing road safety management systems.

현대사회는 21세기 초반 지식정보사회를 지나 지능정보사회로 바뀌어 가고 있다. 본 연구에서는 지능정보사회 에서 요구되는 학습자의 핵심역량을 신장시키기 위하여 인공지능의 한 분야인 머신러닝을 기반으로 소프트웨어 교육 교수-학습 모형을 개발하였다. 본 모형은 인공지능 자체에 대한 학습의 부담감을 줄이고, 머신러닝을 활용 하여 문제를 해결하는 과정에서 핵심역량을 신장시키는 것에 중점을 두었다. 개발된 모형의 구체적인 단계는 문 제인식 및 분석, 데이터 수집, 데이터 가공 및 선별, ML모델 훈련 및 평가, ML프로그래밍, 적용 및 해결, 공유 및 환류의 7단계로 구성되어 있다. 본 연구에서 개발한 모형을 학생과 학부모를 대상으로 적용한 결과 긍정적인 반응을 얻을 수 있었으며, 이를 통해 머신러닝 기반의 소프트웨어 교육 프로그램의 개발 및 운영에 작은 밑거름 을 제시할 수 있을 것으로 기대한다.

The society we are living in has being changed to the age of the intelligent information society after passing through the knowledge-based information society in the early 21st century. In this study, we have developed the instructional model for software education based on the machine learning which is a field of artificial intelligence( AI) to enhance the core competencies of learners required in the intelligent information society. This model is focusing on enhancing the core competencies through the process of problem-solving as well as reducing the burden of learning about AI itself. The specific stages of the developed model are consisted of seven levels which are ‘Problem Recognition and Analysis’, ‘Data Collection’, ‘Data Processing and Feature Extraction’, ‘ML Model Training and Evaluation’, ‘ML Programming’, ‘Application and Problem Solving’, and ‘Share and Feedback’. As a result of applying the developed model in this study, we were able to observe the positive response about learning from the students and parents. We hope that this research could suggest the future direction of not only the instructional design but also operation of software education program based on machine learning.

과거 주가 데이터와 금융 관련 빅 데이터를 사용해 머신러닝 기법으로 주식시장을 예측하는 연구는 다양하게 있어 왔지만, HTS와 MTS를 통해 거래가 가능한 주가지수 연동 ETF가 생기면서 주가지수를 예측하는 연구가 최근 주목받고 있다. 본 논문에서는 KOSPI 연동 ETF를 거래할 목적으로 KOSPI의 상승 예측을 위한 머신러닝 모델과 하락 예측을 위한 모델을 각각 구현한다. 이들 모델은 매개변수의 그리드 탐색을 통해 최적화 된다. 또한 정밀도를 개선해 ETF 거래 수익률을 높일 수 있도록 개별 모델들을 조합한 하이브리드 머신러닝 모델을 제안한다. 예측 모델의 성능은 정확도와 ETF 거래 수익률에 큰 영향을 미치는 정밀도로 평가된다. 하이브리드 상승 예측 모델의 정확도와 정밀도는 72.1 %와 63.8 %이고 하락 예측 모델은 79.8 %와 64.3 %이다. 하이브리드 하락 예측 모델에서 정밀도는 개별 모델 보다 최소 14.3 %, 최대 20.5 % 개선되었다. 테스트 기간에 하이브리드 모델은 하락에서 10.49 %, 상승에서 25.91 %의 ETF 거래 수익률을 보였다. 인버스×2와 레버리지 ETF로 거래하면 수익률을 1.5 ~ 2배로 높일 수 있다. 하락 예측 머신러닝 모델에 대한 추가 연구로 수익률을 더 높일 수 있을 것으로 기대한다.

In the past, there have been various studies on predicting the stock market by machine learning techniques using stock price data and financial big data. As stock index ETFs that can be traded through HTS and MTS are created, research on predicting stock indices has recently attracted attention. In this paper, machine learning models for KOSPI's up and down predictions are implemented separately. These models are optimized through a grid search of their control parameters. In addition, a hybrid machine learning model that combines individual models is proposed to improve the precision and increase the ETF trading return. The performance of the predictiion models is evaluated by the accuracy and the precision that determines the ETF trading return. The accuracy and precision of the hybrid up prediction model are 72.1 % and 63.8 %, and those of the down prediction model are 79.8% and 64.3%. The precision of the hybrid down prediction model is improved by at least 14.3 % and at most 20.5 %. The hybrid up and down prediction models show an ETF trading return of 10.49%, and 25.91%, respectively. Trading inverse×2 and leverage ETF can increase the return by 1.5 to 2 times. Further research on a down prediction machine learning model is expected to increase the rate of return.

본 연구는 당뇨병 치료제 후보약물 정보를 이용하여 항당뇨에 영향을 미치는 물질구조를 발견하는데 목적이 있다. 정량적구조 활성관계를 이용한 기계 학습 모델을 만들고 부분최소자승 알고리즘을 통해 실험데이터 별로 결정계수를 파악 한 후 변수중요도척도를 활용하여 주요 분자표현자를 도출하였다. 연구 결과, 후보약물 구조정보를 반영한 molecular access system fingerprint 데이터로 분석한 결과가 in vitro 데이터를 이용한 분석 결과보다 설명력이 높았으며, 항당뇨에 영향을 미치는 주요 분자표현자 역시 다양하게 도출할 수 있었다. 제안된 항당뇨 예측 및 주요인자 분석 방법을 활용한다면 유사한 과정을 반복 실험하는 기존 신약개발 방식과는 달리, 많은 비용과 시간이 소요되는 후보물질 스크리닝 (screening) 기간을 최소화하고, 신약개발 탐색기간도 단축하는 계기가 될 수 있을 것으로 기대한다.

The purpose of this study is to find out the structure of the substance that affects antidiabetic using the candidate drug information for diabetes treatment. A quantitative structure activity relationship model based on machine learning method was constructed and major molecular descriptors were determined for each experimental data variables from coefficient values using a partial least squares algorithm. The results of the analysis of the molecular access system fingerprint data reflecting the candidate drug structure information were higher than those of the in vitro data analysis in terms of goodness-of-fit, and the major molecular expression factors affecting the antidiabetic effect were also variously derived. If the proposed method is applied to the new drug development environment, it is possible to reduce the cost for conducting candidate screening experiment and to shorten the search time for new drug development.

이 연구는 청소년기의 행복 수준에 영향을 미치는 요인을 생태체계적 관점에서 고찰하고 행복 수준에 대한 발달요인의 예측 가능성을 머신러닝 분석을 통해 탐색하였다. 이를 위해 한국아동․청소년패널조사2018(KCYPS) 데이터 중 2차(2019년), 4차(2021년), 6차(2023년) 응답 자료를 사용하였으며, 분석을 위해 잠재계층분석과 머신러닝 분석을 활용하였다. 분석결과, 행복 변화 양상에 따라 ‘유지형’(중간 수준의 행복지속), ‘부익부형’(높은 행복 수준 유지․상승), ‘빈익빈형’(낮은 행복 수준 지속․하락), ‘조정형’(높은 행복수준에서 하향 조정)으로 명명하였고, 방향성이 뚜렷한 ‘부익부형’, ‘유지형’, ‘빈익빈형’을 주요 집단으로설정하였다. 이후 발달요인을 통해 ‘부익부형’과 ‘빈익빈형’을 예측하기 위한 머신러닝 분석을 진행하였다. ‘부익부형’은 삶의 만족도, 우울, 자아존중감, 현실비행이 계층을 예측하는 중요한 요인이었고, ‘빈익빈형’은 자아존중감, 부모의 자아존중감과 부모의 따스함, 친구관계, 부모의 자율성지지가 중요한 예측요인으로 확인되었다. 이러한 결과는 행복계층에 따라 다른 개입이 필요할 수 있음을 의미한다. 따라서 낮은 행복수준을 일반수준으로 높이기 위해서는 심리 사회적 접근이 필요하고, 특히 부모와 또래관계에 대한 접근이 함께 이루어져야 하며, 일반수준에서 높은 행복수준으로 높이기 위해서는 심리적 접근이 효과적일 수 있겠다. 마지막으로 논의에서는 청소년 행복 증진을 위해 심리적 지원과 환경개선을 통한 심리및 복지적 접근의 필요성을 제안하였다.

This study aimed to explore the factors influencing adolescents’ happiness from an ecological perspective and to examine the predictive power of developmental variables on happiness levels using machine learning analysis. For this purpose, data from the 2nd (2019), 4th (2021), and 6th (2023) waves of the Korean Child and Youth Panel Survey 2018 (KCYPS 2018) were used. Latent class analysis and machine learning techniques were applied to analyze the patterns of change in happiness. The analysis results categorized happiness change patterns as: ‘Maintaining’ (sustained intermediate happiness), ‘high-to-higher’ (maintained and rising high happiness), ‘low-to-lower’ (sustained and declining low happiness), and ‘Adjusting’ (downward adjustment from high happiness). Among these, the ‘high-to-higher’, ‘Maintaining’ and ‘low-to-lower’ groups were selected as the main analytic groups due to their clear directional trends. Machine learning analyses were then conducted to predict the “low-to-lower” and “high-to-higher” groups using various developmental factors. For the high-to-higher group, key predictors included life satisfaction, depression, self-esteem, and deviant behaviors. In contrast, predictors for the low-to-lower group were self-esteem, parental self-esteem, parental warmth, peer relationships, and parental autonomy support. These findings suggest the need for differentiated interventions according to the pattern of happiness. Specifically, psychosocial approaches?including support for parent and peer relationships?may be effective in raising happiness from low to average levels, while psychological approaches may be more suitable for enhancing happiness from average to high levels. Finally, the discussion emphasizes the importance of psychological support and environmental improvements as a combined strategy to promote adolescent well-being.

냉동 컨테이너의 고장은 큰 비용의 손실을 야기하지만, 현재 냉동 컨테이너의 알람 체계는 효율성이 떨어진다. 기존에 냉동 시스템의 시뮬레이션 데이터를 활용한 연구는 존재하지만, 냉동 컨테이너의 실제 운영 데이터를 활용한 연구는 부족하다. 이에 본 연구는 실제 냉동 컨테이너 운영 데이터를 활용하여 고장 원인을 분류하였다. 실제 데이터 에서는 데이터 불균형이 발생하였으며 ENN-SMOTE, 클래스 가중치를 둔 Logistic 회귀분석과 본 연구에서 개발한 2-stage 알고리즘을 비교하여 데이터 불균형문제를 해결하였다. 2-stage 알고리즘은 XGboost, LGBoost, DNN을 사용하여 첫 번째 단계에서는 고장 및 정상을 분류하고, 두 번째 단계에서는 고장의 원인을 분류하는 알고리즘이다. 2-stage 알고리즘에서 LGBoost를 사용한 모델이 99.16%의 정확도로 가장 우수하였다. 본 연구는 데이터 불균형을 해결하기 위해 2-stage 알고리즘을 활용한 최종모델을 제안하며 이는 다른 산업에도 활용할 수 있을 것으로 사료된다.

The failure of the reefer container causes a great loss of cost, but the current reefer container alarm system is inefficient. Existing studies using simulation data of refrigeration systems exist, but studies using actual operation data of refrigeration containers are lacking. Therefore, this study classified the causes of failure using actual refrigerated container operation data. Data imbalance occurred in the actual data, and the data imbalance problem was solved by comparing the logistic regression analysis with ENN-SMOTE and class weight with the 2-stage algorithm developed in this study. The 2-stage algorithm uses XGboost, LGBoost, and DNN to classify faults and normalities in the first step, and to classify the causes of faults in the second step. The model using LGBoost in the 2-stage algorithm was the best with 99.16% accuracy. This study proposes a final model using a two-stage algorithm to solve data imbalance, which is thought to be applicable to other industries.