• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.564-564
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• 2016

개념적 수문 모형은 탱크의 개수, 탱크 간 관계구조, 그리고 저류량과 유출량 간 선형/비선형 관계 정의 방식 등에 따라 다양한 형태로 개발되어왔으며, 각 모형마다 매개변수 수 및 입력 자료가 상이하다. 모형의 매개변수가 많아지면 결과가 좋게 나타날 수 있으나, 늘어난 매개변수에 대해 물리적 의미를 부여하고 해석하기가 쉽지 않다. 단순한 모형은 보정이 용이하고 그 특성상 실무에서 널리 이용되고 있으나, 물순환 구조가 복잡한 유역에 대해서는 적용성이 떨어질 수 있다. 하지만 매개변수의 수가 많은 모형이 적은 모형에 비해 항상 결과가 좋은 것은 아니다. 복잡한 모형은 부족한 안정성에 의해 보정 기간에서는 결과가 좋았으나, 검정 기간 대해 결과가 안 좋을 수도 있으며 이에 대한 평가가 필요하다. 본 연구에서는 국내에서 주로 이용되는 개념적 모형을 대상으로 모형의 복잡성과의 정확도의 관계를 비교 평가하고자 한다. 대상 모형으로는 수정 3단 Tank 모형, Im's Tank 모형, Two-Parametric Hyperbolic Model (TPHM), 그리고 Daily Watershed Streamflow Model (DAWAST)을 선정하였고, 대상유역으로는 이동저수지 상류에 위치한 2개 유역을 선정하였다. 모형 간 비교를 위한 정량적 통계적 지표로 $R^2$, Nash-Sutcliffe efficiency (NSE), root mean square error-observations standard deviation ratio (RSR), 그리고 percent bias (PBIAS)를 이용하였다. 본 연구 결과는 개념적 수문 모형에 대한 이해를 증진하고, 장기유출 해석을 위한 수문 모형의 선택 시 모형의 복잡도 및 정확도의 관점에서 도움을 줄 수 있는 기초자료로 이용될 수 있을 것이다.

• School Mathematics
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• v.12 no.2
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• pp.219-237
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• 2010

On inquiry of international comparison assessment, the Korean students achieve high scores in mathematics while they achieve relatively low scores in responses of the affective questionnaire. It can be an important point in mathematics education of Korea, but there are few studies which explore the specific reasons. So in this study, we analysed the results of PISA 2003(in math domain) based on multiple regression analysis and correlation analysis to investigate the reasons and features of those phenomena. We compared the results of Korean students with students of other countries. As a result, there were 7 factors which effect on Korean students' affective domain in mathematics learning and they were statistically significant. According to this study, it needs to improve students' positive attitudes to their school, mathematical interest, and positive self-concept. And it needs to develop an actual instrument to explore the affective domain which effect on mathematics learning.

• Journal of the Korea Society for Simulation
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• v.21 no.3
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• pp.71-78
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• 2012

This research discusses the application of the control variables to achieve a more precise estimation for the target response in queueing network simulation. The efficiency of control variable method in estimating the response depends upon how we choose a set of control variables strongly correlated with the response and how we construct a function of selected control variables. For a class of queuing network simulations, the random variables that drive the simulation are basically the service-time and routing probability random variables. Most of applications of control variable method focus on utilization of the service time random variables for constructing a controlled estimator. This research attempts to suggest a controlled estimator which uses these two kinds of random variables and explore the efficiency of these estimators in estimating the reponses for computer network system. Simulation experiments on this model show the promising results for application of routing probability control variables. We consider the applications of the routing probability control variables to various simulation models and combined control variables using information of service time and routing probability together in constructing a control variable as future researches.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.195-198
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• 2006

실시간 프로그램은 항공기, 선박, 철도 예매 시스템 등 다양한 분야에서 사용되고 있으며, 그 개발자는 논리적, 시간적 정확성을 고려해야 한다. 시간적 정확성은 실시간 프로그램에서 가장 중요한 부분이며, 이를 위한 데드라인은 개발자에 의해 정의된다. 따라서 개발자는 데드라인의 정의를 위하여 기준점을 제시할 수 있는 정적 실행시간 분석이 필요하다. 정적 실행시간 분석에서 프로그램의 반복횟수의 분석은 큰 비중을 차지한다. 기존 연구에서 반복횟수의 분석은 사용자 입력에 의존하였고 현재 반복횟수 분석을 자동화하는 연구가 진행 중이다. 하지만 반복횟수의 분석은 반복횟수에 영향을 주는 제어변수의 결정정책에 따라 결과가 달라진다. 따라서 본 논문에서는 PS-Block구조를 기반으로 반복 횟수에 영향을 주는 제어변수들을 종합적으로 분석하여 보다 정밀하고 사용자의 입력을 자동화하는 반복횟수의 분석이 가능한 방법을 제시한다. 이로써 정적 실행시간 분석은 반복횟수의 정밀한 분석을 통하여 분석 결과의 정확도를 높이고 신뢰성을 향상시킬 수 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.407-411
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• 2009

This study presents the analysis of the identifications and determinations of the material parameters in the developed model in the former paper and their effects on the stress paths. It was shown that the influences of the parameters, specially involved in the strain rate and the viscous nucleus, were in generally acceptable range. From this point, the model was modified by identifying the plastic yield surface and the viscous yield surface in the same mathematical form. The modified model was successful in simulating stress path.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.377-380
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• 2012

경영성과에 영향을 미치는 주요 요인으로 연구되고 있는 또 다른 변수 중의 하나는 근로환경이며, 일부 연구자들에 의하면 근로환경은 경영성과에 여러 형태로 영향을 미친다. 또한 중소기업의 생존력은 중견기업이나 대기업에 비해 떨어질 수밖에 없으므로 이러한 정부의 지원뿐만 아니라 이러한 신생의 기술 기반의 중소기업을 대상으로 경영목표에서 출발하여 여러 변수가 재무성과에 미치는 요인을 분석하여 그 시사점을 활용하는 것은 큰 의미가 있을 것이다. 따라서 본 연구는 기술 기반의 신생중소기업의 경영성과에 외부지원과 내부환경요소가 어떠한 형태로 영향을 미치는 지를 종합적으로 분석하고자 개념적모형, 가설 그리고 변수를 조작적으로 정의하여본다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.33-40
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• 2012

This paper proposes a method to implement biological early warning systems(BEWS). This system generates periodically data event using a monitoring daemon and it extracts the feature parameters from this data sets. The feature parameters are derived with 6 variables, x/y coordinates, distance, absolute distance, angle, and fractal dimension. Specially by using the fractal dimension theory, the proposed algorithm define the input features represent the organism characteristics in non-toxic or toxic environment. And to find a moderate algorithm for learning the extracted feature data, the system uses an extended learning algorithm(UChoo) popularly used in machine learning. And this algorithm includes a learning method with the extended data expression to overcome the BEWS environment which the feature sets added periodically by a monitoring daemon. In this algorithm, decision tree classifier define class distribution information using the weight parameter in the extended data expression. Experimental results show that the proposed BEWS is available for environmental toxicity detection.

• Journal of Digital Convergence
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• v.8 no.1
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• pp.71-79
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• 2010

Impact of online social network to cyber community has increased much attention recently. The biggest challenge in fostering a social network is to the extent whether it helps to build human capital network or social community. We propose what critical factors influence the formation of online capital network. The study uses three independent factors as motivation, self disclosure, and interactivity and two dependent factors as knowledge sharing and strengthening relationships to create virtual capital connection. Data collected from 256 university students to test the proposed model. The results of the study shows that all hypothesis are supported except one with strengthening relationship. Implications and limitations of this research are discussed.

• The Mathematical Education
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• v.62 no.1
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• pp.151-173
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• 2023

In this study, we explored factors that affect high school student's affective attitude on mathematics with respect to the school mathematics instructoin, school mathematics assessment, mathematics textbook, private mathematics education, college entrance and career, and social atmosphere. Considering students' grade, major, academic level, gender, and school location, 1,029 high school students participated in the survey. To analyze the survey results, descriptive statistics, t-test, ANOVA, and chi-square test were conducted using SPSS ver 29.0. Results are as follows. First, generally, college entrance and career and school mathematics instruction affected students' affective attitude on mathematics. Second, according to student's academic level and gender, there was a statistically significant difference in the factors affecting the affective attitude on mathematics. Third, according to students' background, there was a statistically significant difference in students' responses to sub-categories of each factor. We suggested that to improve student's affective attitude on mathematics, diversity of the school mathematics instruction, improvement of the mathematics textbook, student's appropriate participation in the private mathematics education, improvement of student's perception of the utilization of the mathematics in the future and the importance of the mathemaitcs in the society, and parents' emotional support are needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3223-3231
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• 2013

Fire service budget must be increased continually to supply sufficient fire service for safety life of people. A way to increases fire service budget is to plan and improve regional resources facilities tax system. The purpose of this articles is to analyzes the relationship between regional resources facilities tax and fire service budget, fire service investment budget, socioeconomic factor, fire service demand. To do this, this study sets up five hypotheses based on the theoretical backgrounds and the past research. The statistical methods used for the verification of hypotheses are multiple regression analysis and t test. The analysis showed that regional resources facilities tax was positive significant variable for fire service investment budget and fire service budget and socioeconomic factor was a positive significant variable for regional resources facilities tax. And the analysis showed that fire and rescue variable of fire demand factor were positive significant for regional resources facilities tax.