• Fire Science and Engineering
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• v.22 no.5
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• pp.1-8
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• 2008

The study is to perform numerical analysis of train fire characteristics in an underground subway tunnel, depending the different locations of ventilation facility. To study the characteristics of train fire, two kinds of worst-case scenarios are selected, based on escape distance, escape time, and fire zone, and trends and thermal environments of tunnel are analyzed by changing the locations of ventilation facility for times. Fire characteristics is calculated by using FLUENT v.6.3.26, and turbulent flow is calculated by using the standard k-${\varepsilon}$ model. The numerical results show distribution of carbon monoxide concentration, temperature, and velocity. The results of this study will contribute to building the most suitable ventilation systems when designing subway stations and tunnels.

• Journal for History of Mathematics
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• v.25 no.3
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• pp.53-75
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• 2012

When imaginary numbers were first encountered in the 16th century, mathematicians were able to calculate the imaginary numbers the same as they are today. However, it required 200 years to mathematically acknowledge the existence of imaginary numbers. The new mathematical situation that arose with a development in mathematics required a harmony of real numbers and imaginary numbers. As a result, the concept of complex number became clear. A history behind the development of complex numbers involved a process of determining a comprehensive perspective that ties real numbers and imaginary numbers in a single category, complex numbers. This came after a resolution of conflict between real numbers and imaginary numbers. This study identified the new perspective and way of mathematical thinking emerging from resolving the conflicts. Also educational implications of the analysis were discussed.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.261-273
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• 2022

This study aims to analyze whether facilities linked to the inside and outside of the station affect the revitalization of commercial spaces inside the station where individual rental stores are clustered. Rent, which can replace sales, was set as the determining factor for revitalization. In addition to the variables related to sales, culture, office work/residential, public institutions, and transportation facilities, the independent variables were the number of daily passengers, which is a location factor of the station, and the product sales business, which accounts for the largest number of industries in the commercial space inside the station. As a result of regression analysis, it was proved that rent has an effect on product sales business, linked sales facilities, transportation facilities, and the number of passengers on board. These results indicate that the formation of sales products that can increase purchasing power and the direction of facility linkage that can increase the inflow population into the station are needed to revitalize commercial spaces in the station. In this study, the establishment of a living-friendly SOC for residents' convenience daily life was suggested as a policy management plan for stations with a high vacancy rate due to reduced vitalization.

• Fire Science and Engineering
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• v.18 no.4
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• pp.103-109
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• 2004

The risk of underground space become an important issue of life safety thought the Taeku subway line Accident. It is essential to study of smoke control screen to minimize the damage of human life because of smoke passage and passenger evacuation routes are on the same vertical and dispersion movement. The Fire modeling result shows the effect of fire control screen can save the evacuation time about 2-2.5 times compare to existing the system However, The designs of fire control screen need to be complied with smoke control ventilation system to present optimum design and the position of installation.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.617-629
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• 2020

In the historical and cultural blocks with the most concentrated urban cultural heritage, the development of both side streets is impacted by the development of the main street, which shows a gradual decline. The loss of placeness on both side streets has resulted in more empty houses. Therefore, it is urgent to pay attention and take countermeasures to the empty houses in historical and cultural blocks. In this study, the vacant houses on Zhongshan Road in Hangzhou, China were taken as the object of study to understand the location theory and the six dimensions of Matthew Carmona's urban design. Meanwhile, it further analyzed the evaluative features of the placeness of the vacant houses in the historical and cultural street, to provide direction and basis for the flexible using of other empty houses in Zhongshan Road. Then by applying the Analytic Hierarchy Process (AHP), it obtained the importance scale of each evaluative feature and compared the evaluation results of experts with the analysis results of cases, getting the results as follows: In the flexible application of vacant houses in historical and cultural street, the evaluation result of placeness indicates that this kind of usage should be in order of societal level, perceptional level, functional level, morphological level, visual hierarchy and temporal level; among the evaluative features, security, identity, usability, individuality, aesthetics, connection, diversity, openness, continuity, accessibility, order and history should be considered in turn.

• School Mathematics
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• v.15 no.2
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• pp.221-241
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• 2013

This study considers the experiment of Inhelder and Piaget(1963) in various aspects, and reveals the characteristics of the 'the formation of a critical mind', 'the transformation into the research question', 'the translation into the experiment', and 'the interpretation of the result of the experiment' in Piaget's genetic epistemology. According to these analyses, this study discusses the educational implications that the results of the Piaget's experiment support the education which raises the student's awareness.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.36-49
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• 2016

A subway system is one of the major transportation modes at a metropolitan area. When it meets the other lines, the metro station, so-called transferring station, is usually threatened by severe pedestrian congestion and safety issue of transit users including the transportation vulnerable. Although transportation planners forecast travel demand at the beginning, it is not easy to predict pedestrian flows precisely for a long term if land use plans have dramatically changed. Due to expensive costs, structural extension of metro stations is limited. Therefore, it requires efficient and technical improvements as meeting the demand of pedestrian and physical characteristics. In this study, the core mechanism of pedestrian movement-based simulation model was introduced and evacuation scenarios were analyzed with the developed model. As a result, the multiple optimal routes for unexpected events at the solid space of the multiple stories are easily searched through the simulator and in the case of Sadang Station, travel time can be reduced by 60% when the evacuation information and intuitive design are provided.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.7
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• pp.485-496
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• 2018

In this paper, the smoke behavior in an underground station on operation of the fans in the ventiliation of the station was measured by the experimental method when the fire occurred in the underground station platform where the platfrom screen door was installed. The ventilation characteristics were compared when the ventilation system was operated and when the ventilation system was not operated when a fire occurred at the platform where the clean door was closed. To simulate the fire smoke, the smoke generated from the smoke generator was heated using a hot air fan. The transmittance was measured using a smoke density meter to quantitatively measure fire smoke. If the screen door is closed and the ventilation system of the underground station does not work, it is confirmed that if a fire occurs in the platform, smoke accumulates inside the platform, evacuating passengers is very difficult and can lead to a very dangerous situation. On the other hand, under the condition that the ventilation facility of the subway station is operated, the smoke evacuates to the outside through the ventilation facility of the underground station, and airflow is formed in the direction from the waiting room to the waiting area, so that the passenger located on the platform can safely evacuate toward the concourse. In the following paper, we will discuss the concurrent effect of tunnel ventilation through tunnel vent near the platform.

• Korean Journal of Social Welfare
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• v.36
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• pp.259-283
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• 1998

This research is based on the assumption that Korea's social consensus among two sides of industry and government on Feb. 2 '98 was not just temporary response to the economic crisis caused by International Monetary Fund financial fund. Some arguments on the applicability of social democracy and corporatism and D. Donnison's perspective on Democratic Socialism are employed in search of an appropriate social consensus model for Korean situation. In the process of analyzing Korean situation in historical context it becomes apparent that there is embryo of stable social consensus beyond the level of tentative social cooperation to overcome the economic crisis. The next step applying the social consensus model to the employment policy for people with disability levels up empirical and theoretical validity of this research. It casts some implications for disability labour market which demands another kind of social consensus among people with disability, employers and the government. These implications include a desirable solution for hard lives of unemployed people with disability in economic difficulties and current policy issues facing Korean government.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.93-101
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• 2005

Seismicity changes associated with foreshocks of large Korean historical earthquakes of MMI > VIII are investigated for earthquake prediction study. A number of tests showed that b-values of foreshocks associated with these large earthquakes are most stable for precursor period of 13 years before the earthquake and rectangular source area of $1.1^{\circ}$ by $1.1^{\circ}$ around the epicenter. The b-values of foreshocks for 11 large events of MMI > VIII for the above foreshock area and precursor period turns out to be smaller than the value of 0.36 for the whole historical earthquakes with average 0.27. Epicenters of these foreshocks of small b-values are distributed close to the location of the main large earthquake. These observations indicate a possibility of predicting large earthquakes by closely monitoring the change of b-value for an extended period over decades in the Korean peninsula.