• International Journal of Highway Engineering
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• v.14 no.6
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• pp.131-138
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• 2012

PURPOSES : Two-lane highways have one lane in each direction, and lane changing and passing maneuvers take place in the opposing lane depending on the availability of passing sight distance. 2001 Korea Highway Capacity Manual (KHCM) is classified into two classes of two-lane highways (Type I, II), and average travel speed and time-delayed rate are used as measures of effectiveness (MOEs). However, since existing two-lane highways have both uninterrupted and interrupted traffic flow-system elements, a variety of free-flow speeds exhibits in two-lane highways. In addition, it is necessary to check if the linear-relationship between volumes and time-delayed rate is appropriate. Then, this study is to reestablish the relationship between average travel speed, time-delayed rate, and flow. METHODS : TWOPAS model was selected to conduct this study, and the free-flow speeds of passenger cars and the percentage of following vehicles observed in two-lane highways were applied to the model as the input. The revised relationships were developed from the computer simulation. RESULTS : In the revised average travel speed vs. flow relationship, the free-flow speed of 90km/h and 70km/h were added. It shows that the relationship between time delayed-rate and flow appeared to be appropriate with the log-function form and that there was no difference in time-delayed rate between the free flow speeds. In addition to revise the relationships, the speed prediction model and the time-delayed rate prediction model were also developed. CONCLUSIONS : The revised relationships between average travel speed, time-delayed rate, and flow would be useful in estimating the Level of Service(LOS) of a two-lane highway.

• Korean Management Science Review
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• v.20 no.2
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• pp.95-111
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• 2003

The standard issue in the information and telecommunication industry is increasingly important with the rapid development of technology. This paper proposes an index model which can measure the degree of standardization in the Korean information and telecommunication field. We first classified ICT sector into 14 sub-sectors. Then for each sub-sector, we considered a set of important determinants to measure the level of standardization, and constructed a linear equation using this set of determinants. Finally we estimated the relative degree of importance of each determinant using the AHP methodology. The proposed model found that overall level of standardization in the Korean ICT industry is relatively low, and ‘IMT-2000 technology’ and ‘computer network technology’ among 14 sub-sectors are highly standardized sub-sectors. The validity of the proposed model was also partially proved using two different methods, holistic and historical approach.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.177-181
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• 1996

Systematic classification system for standardization in telecommunication is essential to the standardization R&D strategy. This paper suggests a new reference model for development of work area and classification scheme related to the telecommunications standardization : Cubic and matrix approach. Standardization Work Areas(SWAs) that are upper level of the reference model are classified by its main role and function reflecting the market trends and user needs. Standardization expertise is lower level scheme, which can be regarded as the different possible layers of standardization to be applied to each one of the SWAs grouped under upper level scheme. A new reference model consists of two planes that are SWAs plane and Standardization layer plane. Finally the reference model for classification of SWAs in telecommunication mapping onto matrix table that row and column are defined by SWAs and standardization layer respectively.

• Journal of Korea Planning Association
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• v.53 no.7
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• pp.67-86
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• 2018

This paper attempted to analyze impacts of transition in electricity generation system on a national economy and environmental level in Korea using a recursive computable general equilibrium(CGE) model. In particular, the paper presented a hybrid model combining the top-down CGE model with the bottom-up model which describes the structure of electricity production in detail. The impacts were analyzed by two policy scenarios base on the basic plan for electricity supply and demand proposed by the Korean government. As a result, the paper specifically showed that there exists a trade-off relationship in the policy-making between economic efficiency and environmental level. The paper also suggested that the transition in electricity generation system should be done more gradually and carefully.

• Journal of Korean Elementary Science Education
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• v.20 no.2
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• pp.217-228
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• 2001

The purpose of this study was to investigate the effect of learning cycle model on the changes of electricity conceptions of elementary students. Four classes in forth grade of an elementary school in Busan were selected and two of them were served as experimental group and the others as control group. The experimental group were taught the unit of "Light an electric bulb" in elementary science textbook with teaching model based on teaming cycle and the control group with traditional teaching style. The instruction effects were analyzed through pre and post-test results using questionnaire on the electricity. The results of pre-test showed that there was not a significant difference between experimental group and control group at .05 level, so two groups could be regarded as homogeneous. The mean score of experimental group was significantly higher than that of control group on the post-test at .05 level. And within-group comparison revealed that both groups made improvement on the mean score and that the improvement of each group had significant difference at .05 level. Above results said that the teaching model based on learning cycle, which focuses on hands-on activity and considers each student as an active subject, was more effective than traditional teaching style in improving the formation of scientific conceptions on electricity.ectricity.

• International Journal of High-Rise Buildings
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• v.12 no.1
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• pp.49-61
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• 2023

The transit-oriented development (TOD) model can effectively help to solve urban problems and promote sustainable urban development. The United States and Japan are widely considered the earliest two countries to start TOD practices; however, the origins of TOD models in the two countries were different. The TOD practices in the two countries formed distinct characteristics, yet their differences have been underexplored. This study aims to grasp the characteristics of the TOD model in the two countries through a systematic comparative analysis of 10 typical cities in the United States and Japan that have adopted the TOD model. This paper compares the case cities' three key aspects of the TOD model: public transit system, spatial form, and land use, and summarizes the characteristics of TOD models in the two countries from a city-level perspective, to help deepen the global understanding of TOD.

• Spatial Information Research
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• v.14 no.3 s.38
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• pp.321-334
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• 2006

3D spatial data are of increasing interest in landscape analysis, urban planning and map services based on Web, because of its reality. But the amount of 3D spatial data are very large in comparison with 2D spatial data. Therefore it is necessary to have a efficient methods to transfer and visualize 3D spatial data. The concept of Level of Detail in Computer Graphics is effective. This paper briefly presents two LOD data models of data transmission based on the spatial data model of international standards. First, it is separated LOD model that gives a LOD level to object. Second is Selective LOD model that gives a LOD level to object's element. We compared the efficiency of 3D data transmission based on two LOD model.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.89-95
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• 2006

This study has numerically modelled the combustion processes of the turbulent swirling premixed lifted flames in the low-swirl burner (LSB). In these turbulent swirling premixed flames, the four tangentially-injected air jets induce the turbulent swirling flow which plays the crucial role to stabilize the turbulent lifted flame. In the present approach, the turbulence-chemistry interaction is represented by the level-set based flamelet model. Two-dimensional and three-dimensional computations are made for the various swirl numbers and nozzle length. In terms of the centerline velocity profiles and flame liftoff heights, numerical results are compared with experimental data The three-dimensional approach yields the much better conformity with agreements with measurements without any analytic assumptions on the inlet swirl profiles, compared to the two-dimensional approach. Numerical clearly results indicate that the present level-set based flamelet approach has realistically simulated the structure and stabilization mechanism of the turbulent swirling stoichiometric and lean-premixed lifted flames in the low-swirl burner.

• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.111-123
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• 2005

A network design model has been proposed. which represents a transportation facility investment decision problem. The model takes the discrete hi-level programming form in which two types of decision makers, government and travelers, are involved. The model is characterized by its ability to address the total social costs occurring in transportation networks and to estimate the equilibrium link volumes in multi-modal networks. Travel time and volume for each link in the multi-modal network are predicted by a joint modal split/traffic assignment model. An efficient solution algorithm has been developed and an illustrative example has been presented.

• The Journal of Korean Association of Computer Education
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• v.4 no.1
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• pp.119-126
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• 2001

In this paper, a highly effective learning model that can be applied to the 7th level-based curriculum, which will begin in high schools in the year 2002, will be proposed. Two learning models that have different perspectives on dividing the students into level groups(diagnostic evaluation model and formative evaluation model) were introduced, and teaching materials for each model were developed. After applying the teaching materials to actual classes, the achievement rate of the students was analyzed. According to the results of this research, the achievement rate of students is affected by the point of time at which they are divided into level groups, and formative evaluation proved to be the superior learning model dividing students into level groups.