• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1285-1296
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• 2013

The fundamental concerns of this paper are to analyze the effects of student course evaluation using subject characteristic and student characteristic variables. We use a 2-level hierarchical linear model since the data structure of subject characteristic and student characteristic variables is multilevel. Four models we consider are as follows; (1) null model, (2) random coefficient model, (3) mean as outcomes model, (4) intercepts and slopes as outcomes model. The results of the analysis were given as follows. First, the result of null model was that subject characteristics effects on course evaluation had much larger than student characteristics. Second, the result of conditional model specifying subject and student level predictors revealed that class size, grade, tenure, mean GPA of the class, native class for level-1, and sex, department category, admission method, mean GPA of the student for level-2 had statistically significant effects on course evaluation. The explained variance was 13% in subject level, 13% in student level.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.12-28
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• 2019

Road geometry is one of the many factors that cause crashes, but the effect on traffic accident depends on weather conditions even under the same road geometry. This study identifies the variables affecting the crash severity by matching the highway accident data and weather data for 14 years from 2001 to 2014. A hierarchical ordered Logit model is used to reflect the effects of road geometry and weather condition interactions on crash severity, as well as the correlation between individual crashes in a region. Among the hierarchical models, we apply a random intercept model including interaction variables between road geometry and weather condition and a random coefficient model including regional weather characteristics as upper-level variables. As a result, it is confirmed that the effects of toll, ramp, downhill slope of 3% or more, and concrete barrier on the crash severity vary depending on weather conditions. It also shows that the combined effects of road geometry and weather conditions may not be linear depending on rainfall or snowfall levels. Finally, we suggest safety improvement measures based on the results of this study, which are expected to reduce the severity of traffic accidents in the future.

• Korean Journal of Social Welfare
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• v.66 no.4
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• pp.77-100
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• 2014

To validate the effects of students' individual factor, school organizational factor, and teacher factor on violent behavior toward peers in school, this study applied Hierarchical Linear Modeling and analyzed it using the HLM 7 program. To this end, it used survey data of students from 50 middle schools in Seoul and Gyeonggi province. A total of 1,777 cases from 50 middle schools were used for individual student-level analysis (Level 1), and used for school-level analysis (Level-2). According to the results of the analysis, student-level variables such as attitude toward violence, experience of child abuse at home, and delinquent peers had significant effects on school violence. The effects of violent discipline by teacher, which are used as a school-level variable, was statistically significant. Based on the result of the study, action plans and policies to resolve school violence were discussed.

• Korean Journal of Heritage: History & Science
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• v.47 no.3
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• pp.60-85
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• 2014

The study is for tracing the mutational process, considering the transformational process of wooden chamber tombs in Gyoungju region during 2~6 century. In addition, class features and the meaning of tombs were studied. First of all, the wooden chamber tombs were classified into 10 different styles(1A~IVC), based on the filling materials, the ways of structure, and the structure of burial chamber. There were only one or two tombs that belongs to the highest classes 'Ga'~'Da' in each period, which has the numeral features. Furthermore, the styles of the central wooden chamber tombs according to the period and the region have distinctive features and have changed so far. It shows that there are the rank among the tombs in the regions. In other words, regarding the ranks of the class 'Ga'~'Cha', there were strict rules and the limitations on the size of the tombs and the number and the quality of the burial relics. It means that the inner-outer size or the structure of the tombs and the number, quality of the burial goods depended on the buried person's birth or social classes, or achievements. Based on Shila social classes, the class 'Ga' tombs were for the highest classes when considered the size, burial relics, and the quality. The class 'Na' and 'Da' tombs were for the higher classes, 'Ma' for middle classes, 'Ba', 'Sa' for lower classes. In addition, 'Ah', 'Ja' tombs were for higher commoner, 'Cha' for lower commoner. Thus, class 'Ga'~'Sa' is the leading class of Shila.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.123-133
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• 2007

This study analyzed whether a transit network with hierarchy is efficient or not, and if transit network hierarchy has cost efficiency, then which condition guarantees the efficiency of the transit network hierarchy. The authors modeled the total cost of the transit network and suggested the conditions in which the transit network hierarchy has cost efficiency through comparing the cost of the transit network with and without hierarchy. The efficiency of transit network hierarchy is guaranteed when the travel cost savings induced by using a higher hierarchy transit network is larger than the increasing non-travel cost, which is the sum of access cost, waiting cost, and operating cost, induced by the introduction of a higher hierarchy transit network. This result is consistent with common sense and with the concept of cost and benefit analysis. If a passenger traveling within the area divided by a higher hierarchy transit network uses only a lower hierarchy transit network and the passenger traveling out of the area divided by the higher hierarchy transit network uses both lower and higher hierarchy transit networks, the travel demand using the higher hierarchy transit network is inversely proportional to the square of the line spacing. This means that the transit network becomes more efficient and small increases of travel demand guarantee the efficiency of the transit network hierarchy as the connectivity of the network becomes higher. This result shows that transit networks have economies of aggregation. This study is the first analytical research on transit network hierarchy and is expected to be a basis for numerical research. However, numerical research should complement this study, since analytical research has some limitations for considering a real network.

• Science of Emotion and Sensibility
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• v.9 no.spc3
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• pp.209-224
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• 2006

Hierarchy which is often named as the tree-structure is used to reduce complexity and show primitive structures of complicated information. This paper aims at explaining information-visualization methods using hierarchies in multimedia domains and prospecting the possible applications by examining how they affect the user's tasks involved in information-seeking activities. As a result, four types of information visualization methods named Treemap, Hyperbolic, Cone Tree and DOI Tree employed in multimedia domain, are presented and pros and cons of each method are explained in this paper. Another important part is defining the core tasks and other related-tasks in information-seeking activities, such as, overview, zoom, filter, details-on-demand, relate, history, and extract. Followings are major findings. Treemap uses 'overview' as the core task, which makes user to gain a overall meaning of the whole information cluster. Hyperbolic and DOI Tree apply 'Boom' task through the function of focus+context or by the function of meaningful scaling to magnify or downsize each node. Cone Tree, also, makes the information organizer to classify the patterns of information acquired in the process of users' information-seeking activities by using 'extract' task. Through this study, it is finally found out that the information-visualization methods using hierarchies in multimedia domains should incorporate the wide variety of functional needs related to users' information-seeking behaviors beyond the visual representation of information.

• 한국벤처창업학회:학술대회논문집
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• 2019.04a
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• pp.103-107
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• 2019

최근 에어비앤비나 우버와 같은 협력적 소비 기반의 비즈니스모델을 가진 공유경제가 성장하고 있다. 본 논문은 공유경제에 대한 개념을 정의하고, 이용의도에 미치는 영향을 분석하였다. 본 논문은 경제적, 기능적, 경험적, 사회적 가치를 포함한 4가지 지각된 가치와 주관적 규범, 이미지, 사회적 임계점을 구성하는 3가지 사회적 영향이 공유경제 이용의도에 미치는 영향을 알아보고 신뢰와 사회적 규범, 네트워크와 사회구조를 포함한 사회적자본의 조절효과에 관심을 두고 있다. 가설을 검증하고자 온라인과 오프라인에서 설문조사를 실시하였고, 지각된 가치와 사회적 영향이 공유경제 이용의도에 미치는 영향을 알아보고자 변수별로 다중회귀분석을 실시하였다. 또한 사회적자본의 조절효과를 알아보기 위하여 위계적인 회귀분석을 실시하였다. 다중회귀분석 결과는 다음과 같다. 지각된 가치 중 경제적, 경험적 가치는 공유경제 이용의도에 영향을 미치는 것으로 나타났다. 위계적인 회귀분석의 결과에서 사회적자본은 지각된 가치와 사회적 영향의 공유경제 이용의도 관계에 있어 조절적인 영향을 미치는 것으로 나타났다. 본 연구는 지각된 가치를 통합적 분석, 기존 공유경제 연구에서 자주 다뤄지지 않았던 사회적 영향과 사회적자본의 요인을 다룬 점에 의미가 있지만, 설문조사 결과의 한계가 있었기에 향후 새로운 연구 방향성을 제시할 수 있다.

• Korean Journal of Cognitive Science
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• v.3 no.2
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• pp.177-223
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• 1992

Three studies examined the Keil's(1983)arguments that ontological categories form a hierarchy and they could be strong constraints on induction.In experiment 1,the jungments of sentence acceptability of 5-year-olds and adults showed that they have the hierarchically structured ontological knowledge.In experiment 2,it has been demonstrated that the both age group of subjects use their ontological knowledge to make inferences about the properties of the unknown things described in terms of a predicate.In the last experiment it has been demonstrated that subject can use the ontological knowledge in order to infer what other things could have the unknown organs.

• Journal of Digital Convergence
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• v.9 no.4
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• pp.115-130
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• 2011

The purpose of this study is to examine the effect of career plateau(structural and content plateau) on IT service technical engineers' career satisfaction and career withdrawal intention. Survey data were collected from 161 IT service technical engineers. The results indicated that structural and content plateau were negatively related to career satisfaction, and content plateau was positively related to career withdrawal intention, but not structural plateau. In addition, the results of hierarchical multiple regressions indicated that content plateau had stronger effect on career satisfaction and career withdrawal intention then content plateau.

• Journal of Science Education
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• v.34 no.2
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• pp.237-245
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• 2010

The purpose of this study was to analyze hierarchy for high school students' concepts about genetics. The assessment of genetics related concept was conducted for 10th and 11th grade students and a hierarchy map was schematized based on the evaluation result using Knowledge State Analysis Method. Some differences were found when comparing the result of whole students' hierarchy with hierarchy on 7th national science education curriculum. In analyzing hierarchy by grade, concepts of highest and lowest level turned out same but some concepts of middle level changed. In case of analysis of hierarchy for concepts about genetics by score, as score was higher, the number of concept in lower level became larger and the relationship among concepts became more structurized. Following studies are required to develop specific teaching strategies for having effective genetics concept and conduct case study of applying the concept hierarchy through this method to class in the field.