• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.134-134
• /
• 2022

Streamflow forecasting plays a crucial role in water resource control, especially in highly urbanized areas that are very vulnerable to flooding during heavy rainfall event. In addition to providing the accurate prediction, the evaluation of effects and importance of the input predictors can contribute to water manager. Recently, machine learning techniques have applied their advantages for modeling complex and nonlinear hydrological processes. However, the techniques have not considered properly the importance and uncertainty of the predictor variables. To address these concerns, we applied the GA-BART, that integrates a genetic algorithm (GA) with the Bayesian additive regression tree (BART) model for hourly streamflow forecasting and analyzing input predictors. The Jungrang urban basin was selected as a case study and a database was established based on 39 heavy rainfall events during 2003 and 2020 from the rain gauges and monitoring stations. For the goal of this study, we used a combination of inputs that included the areal rainfall of the subbasins at current time step and previous time steps and water level and streamflow of the stations at time step for multistep-ahead streamflow predictions. An analysis of multiple datasets including different input predictors was performed to define the optimal set for streamflow forecasting. In addition, the GA-BART model could reasonably determine the relative importance of the input variables. The assessment might help water resource managers improve the accuracy of forecasts and early flood warnings in the basin.

• 한국식생활문화학회지
• /
• 제17권2호
• /
• pp.120-130
• /
• 2002

The purpose of this study is to investigate whether a group of predictor variables which constitute four determinants of dining satisfaction do exert a significant influence on messures of dining satisfaction in family restaurant. Canonical correlation analysis is used to achieve the purpose of this study. This technique enables the researcher to test for the effects of a set of predictor variables upon a multidimensional measure of dining satisfaction in family restaurant. Results suggest that multiple determinants are important in determining dining satisfaction in family restaurant. No one determinant can fully explain its complexities. The four determinants also appear to vary in terms of importance. Individual variables within four determinants also appear to vary in terms of importance. Finally, the results of the study provide some insight into the types of marketing strategies that can be successfully used by operators who manage family restaurants.

• 한국안전학회지
• /
• 제37권2호
• /
• pp.18-27
• /
• 2022

Construction accidents are difficult to prevent because several different types of activities occur simultaneously. The current method of accident analysis only indicates the number of occurrences for one or two variables and accidents have not reduced as a result of safety measures that focus solely on individual variables. Even if accident data is analyzed to establish appropriate safety measures, it is difficult to derive significant results due to a large number of data variables, elements, and qualitative records. In this study, in order to simplify the analysis and approach this complex problem logically, data preprocessing techniques, such as latent class cluster analysis (LCCA) and predictor importance were used to discover the most influential variables. Finally, the correlation was analyzed using an alluvial flow diagram consisting of seven variables and fourteen elements based on accident data. The alluvial diagram analysis using reduced variables and elements enabled the identification of accident trends into four categories. The findings of this study demonstrate that complex and diverse construction accident data can yield relevant analysis results, assisting in the prevention of accidents.

• 식품보건융합연구
• /
• 제8권2호
• /
• pp.15-27
• /
• 2022

This study aims to analyze the relative importance of bone age and chronological age in physique according to gender and to identify the relative importance of bone age, chronological age, and physique in physical fitness and motor coordination according to gender in order to alleviate the imbalance between physique and physical fitness in children. A total of 666 children(346 males, 320 females) between the ages of 11-14 were enrolled as subjects, and the skeletal maturation The skeletal maturation were measured by taking hand-wrist. Physical fitness were measured through a total of 4 components: muscular strength. The results of this study. First, physique variables for both males and females aged 11-14 were found to be more significant predictors of bone age than chronological age. Second, for physical fitness in males, in the order of %fat, body water, waist-hip ratio, weight, fat-free mass, and chronological age were more significant predictor variables; and in females, in the order of %fat, fat-free mass, height, chronological age, weight, bone age, fat mass, and body water were more significant predictor variables. For bone age and chronological age in physical fitness, bone age in males and chronological age in females found to be the more representative variables respectively.

• 응용통계연구
• /
• 제34권2호
• /
• pp.177-190
• /
• 2021

랜덤포레스트는 여러 의사결정나무 모형들을 융합하여 안정성과 예측력을 높여주기 때문에 종종 사용되는 방법이다. 예측력을 증가시키는 반면 해석의 용이성을 희생하기 때문에 이를 보상하기 위해 변수의 중요도를 제공한다. 변수의 중요도는 랜덤포레스트를 구축할 때 변수가 얼마나 중요한 역할을 하는지를 알려 준다. 그러나 어떤 예측변수가 다른 예측변수들과 상관되어 있을 때 기존 알고리즘의 변수중요도는 왜곡될 수 있다. 상관된 예측변수들의 하향 편향은 예측변수의 중요도를 실제 중요도보다 낮게 측정하게 한다. 우리는 기존 알고리즘을 수정하여 상관 예측변수의 하향 편향을 회복하는 새로운 알고리즘을 제안한다. 제안된 알고리즘의 성능은 모의 자료에 의해 증명되고 실제 자료에 의해 설명된다.

• 아동학회지
• /
• 제20권3호
• /
• pp.199-216
• /
• 1999

The 121 five-year-old Korean subjects of this study were divided in 3 groups based on their experience in learning a foreign language (English). A battery of tests was administered to measure spoken and written language ability and the 3 metalinguistic domains of phonological, semantic, and syntactic awareness. Spoken language ability was positively correlated with semantic and syntactic awareness. The relative importance of each metalinguistic domain varied with level of written language development. Phonological awareness was the only predictor of decoding. Syntactic awareness and phonological awareness were significant variables in sentence comprehension. Metalinguistic ability was a better predictor of written language development than spoken language ability. Foreign language learning experience had an effect on syntactic awareness: low experience was superior to no experience, but high experience was not superior to low experience.

• Communications for Statistical Applications and Methods
• /
• 제16권1호
• /
• pp.185-193
• /
• 2009

Machine learning methods such as support vector machines and random forests yield nonparametric prediction functions of the form y = $f(x_1,{\ldots},x_p)$. As a sequel to the previous article (Huh and Lee, 2008) for visualizing nonparametric functions, I propose more sensible graphs for visualizing y = $f(x_1,{\ldots},x_p)$ herein which has two clear advantages over the previous simple graphs. New graphs will show a small number of prototype curves of $f(x_1,{\ldots},x_{j-1},x_j,x_{j+1}{\ldots},x_p)$, revealing statistically plausible portion over the interval of $x_j$ which changes with ($x_1,{\ldots},x_{j-1},x_{j+1},{\ldots},x_p$). To complement the visual display, matching importance measures for each of p predictor variables are produced. The proposed graphs and importance measures are validated in simulated settings and demonstrated for an environmental study.

• 한국간호교육학회지
• /
• 제22권3호
• /
• pp.387-395
• /
• 2016

Purpose: The purpose of this study was to identify factors associated with performance of nursing care for postoperative delirium of elderly patients among recovery room nurses. Methods: The research was a cross-sectional, descriptive design using questionnaires. The participants were 99 nurses from five urban recovery rooms. Data were analyzed using descriptive statistics, t-test, ANOVA and multiple regression with SPSS WIN 21.0. Results: The performance level of delirium nursing care was low because its mean score was 3.80 out of 5. Performance of nursing care was significantly positively correlated with the importance of nursing care and self-efficacy. Stepwise multiple regression analysis for performance of nursing care revealed that the most powerful predictor was the importance of nursing care. The importance of nursing care and self-efficacy explained 32.3% of the variance. Conclusion: The results indicate a need to enhance the performance of nursing care for postoperative delirium of elderly patients among recovery room nurses. The findings also suggest that consideration be given to strategies for improving the importance of nursing care and self-efficacy in developing programs to enhance the performance level of nursing care for elderly patients with postoperative delirium.

• 영어어문교육
• /
• 제7권2호
• /
• pp.77-102
• /
• 2002

Factors affecting foreign language learning task are diverse in nature due to the different social and cultural backgrounds so that learners have to somehow use strategies and expressions to adjust diverse factors to their learning environments. The main purpose of this paper is to show how important NNS vs. NNs interaction through CCDL can be in their enhancement of English proficiency by giving examples from their chatting conversation(written conversation) data collected for over two semesters. Chatting as a means of synchronous communication interaction between students from two different cultural backgrounds can act as a predictor of foreign language achievement. Chatting and Telemeet activities have their own advantages in enhancing communicative competence when learning English. By engaging in these synchronous communication activities learners of English from different cultural backgrounds can acquire unique strategies and expressions from which they learn from each other. In short, this study advocates the importance of strategies and patterns foreign language learners can acquire from interaction among culturally different peer groups.

• 복식문화연구
• /
• 제6권2호
• /
• pp.92-108
• /
• 1998

The purpose of this study was designed a) to examine the relative importance for college students' clothing disposal causes and their factor structure: b) to test the effects of gender, clothing satisfaction and family income on clothing disposal determinants; and c) to assess the relationship between clothing purchase determinants and overall clothing satisfaction and clothing disposal determinants. Data (n=660) were collected from college students in Cheju Do. The survey questionnaire composed of a revised Clothing Disposal Determinants Scale, Clothing Purchase Determinants Scale and background variables. First, the most important reasons for clothing disposal were to unfit with body change, get washed our and raise nap on clothe, wornout with long-term use, do not ware for new purchasing clothe, uneasy on wear. Second, factor analysis of the revised Clothing Disposal Determinants Scale revealed five factors; unfitness, fashion change, quality dissatisfaction, product efficiency decrement, and maintenance/inconvenience. Third, female students perceived significantly higher in fashion change and unfitness than male students. Forth, unfitness and product efficiency decrement were significantly discriminated between between clothing satisfaction groups, unfitness and fashion change variables were significantly discriminated between family income groups. fifth, impulsive purchase factor was the best predictor of composite clothing disposal measure, followed by individuality, clothing satisfaction, practicality. The best predictors of each disposal factors were individuality oriented purchasing criterion in unfitness factor. Fashion in fashion change, impulsive purchase in quality dissatisfaction and product efficiency decrement factors, and practicality in maintenance/inconvenience factor. As a whole, the most consistent predictor of clothing disposal determinants was impulsive purchase factor.