• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.121-130
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• 2002

Clean stockers are being used by semiconductor and TFT-LCD manufacturers to store and buffer work in process. Since an important function of a stocker is to keep the contained material clean. The only way to keep the stored product clean is to provide constant clean airflow the product and through stocker, The airflow across the product prevent contamination from settling on the product. Up to now, stocker typically have been configured to receive their laminar airflow from fan filter units that are located on the side of the stocker This type of stocker may have such problems as complexity of structure, increment of temperature, mechanical vibration, initial investment and running cost. In this study, In order to solve the above mentioned problems, new air control system in stocker is proposed, which is to control open ratios of exits that are located on the side of the stocker without fan filter units. Open ratios of exits need to be optimized for the same quantities of airflow in each exit. In this study, static pressure regain was used for the analysis of the open ratios of exits theoretically and Blue Ridge Numerics FEM software, CFDesign, was used fur simulating airflow in stocker. As a result, Open ratios of exits important to provide constant clean airflow can be obtained by the analysis of static pressure regain and was verified by simulation results. Therefore, new air control system in stocker can be used by the semiconductor and TFT-LCD manufacturers.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.7-19
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• 2007

The purpose of posted speeds is to provide a speed that ensures the safety of vehicle flow according to given road situations. Because of this, posted speeds must be carefully examined, and posted speeds at freeway exits and entrances in particular should consider car characteristics. Posted speeds at freeway exits and entrances must take changing speeds due to curve radiuses into consideration and in this study, an 85th percentile speed becomes the most important element to consider. When it is considered that most traffic accidents occur because of variations in speed between cars, posted speeds should be set after considering car traveling characteristics. Within these dimensions, instead of putting significance on an upper direction regulation or lower direction regulation, speed distributions which fit to the characteristics of each road should be fully considered. Accordingly, this study evaluated appropriate posted speeds that will reduce the dangers of traffic accidents through posted speed regulations of roads now in operation by offering a posted speed setting method theory, using entries at Yangji, Yongin, and Cheongwon interchanges as subjects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1178-1186
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• 2002

Clean stockers are being used by semiconductor and TFT-LCD manufacturers to store and buffer work in process. The only way to keep the stored product clean is to provide constant clean airflow the product and through stocker. Up to now, stockers typically have been configured to receive their laminar airflow from fan filter units that are located on the side of the stocker. This type of stocker may have such problems as complexity of structure, increment of temperature, mechanical vibration, initial investment and running cost. In this study, in order to solve the above mentioned problems, new air control system in stocker is proposed, which is to control open ratios of exits that are located on the side of the stocker without fan filter units. In this study, static pressure regain was used for the analysis of the open ratios of exits theoretically and experiment was also conducted using actual clean stocker for TFT-LCD manufacturers and CFDesign, was used for simulating airflow in stocker. As a result, open ratios of exits can be obtained by the analysis of static pressure regain and was verified by experiment and simulation results. Therefore, new air control system in stocker can be used by the semiconductor and TFT-LCD manufacturers.

• Tunnel and Underground Space
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• v.15 no.1 s.54
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• pp.61-70
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• 2005

The objective of this study was to analyze the smoke movement for the case of fire and to determine the interval between emergency exits in long tunnels. Based on Froude modeling, the 1/50 scaled model tunnel (20 m long) was constructed by acrylic tubes and tests were carried out systematically. From the strong relationship between CO propagation time and distance through the tunnel, it was found that the optimal escaping time was 6 minutes in case of 20MW fire. But, regarding passengers' psychological state under fire, another one minute of delay time should be considered. Therefore, the total escaping time should be estimated by 5 minutes. The interval between the emergency exits for vehicle passengers was calculated by 250 m with respect to the 5 minute of escaping time.

• Water for future
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• v.52 no.8
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• pp.16-21
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• 2019

• Journal of the Economic Geographical Society of Korea
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• v.2 no.1_2
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• pp.145-167
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• 1999

The aim the this paper is to explore the processes of three Korean consumer electronics chaebols'entries into, and exits from tile EU in the context of European integration and enlargement and at the global, regional(EU), national and local level. Korean FDI in the EU has increased sharply since the late 1980s, while interacting with the processes of European integration and enlargement. In particular, the chaebols'FDI was caused by reactions against the intensification of Euro-trade regulations. As a result, these defensive entries have led such chaebols to create a strategy of ‘defensive Europeanisation’through the formation of forward and backward linkages between chaebols’affiliates and Korean suppliers within the EU. Nonetheless, defensive FDI has given rise to exits through active relocation within and outside the EU, since the ‘late 1980s’due in the main to (1) sensitive reactions against changing EU trade regulations and (2) failures to maintain cost-competitiveness in particular host regions. Along with these trends, chaebols’entries and exits are placed in contingent and paradoxical structures of the global -regional - national-local nexus, which has resulted from the mismatch of different EU policies such as trade, inward investment and regional policies.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.418-425
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• 1988

Since conventional computer program is workable only with velocity boundary condition, in practical fluid passage such as clean room which usually have wide inlets and outlets, it is not easy to measure velocity itself because of its vector property. Furthermore a certain assumption of velocity at boundaries may lead to physically unreasonable results. From this motivation, we have developed a computer program to predict whole flow field imposed on pressure-based boundary condition which can be measured by relatively simple method. The only additional velocity boundary condition that should be imposed on to make the problem unique, are no slip condition at all walls and zero cross stream velocity at inlet. The result of present study was compared with that by Bernoulli equation being used practically. They were coincident well each other within 5%, therefore the validity of the present method is proved. In the present work, the flow field in a clean room subject to pressure-based boundary conditions at an inlet and two exits was predicted numerically. The pressure difference between the inlet and the left exit which keeps relatively low pressure among two exits is fixed as 150[Pa] and the pressure at the right exit is varied from zero to 150[Pa] by the increment of 25[Pa]. For each cases the flow characteristics in the clean room, the velocity profile at the inlet, and the flow rate through the two exits was predicted. The flow rate through the right exit imposed on relatively higher pressure than the left exit decreased linearly according to the increase of pressure of the right exit. When the pressure of the right exit is increased enough to cause back flow at the exit, the flow rate is rapidly decreased.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.419-425
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• 2021

This study analyzed the safety of evacuation according to the number of exits and the direction of evacuation routes with evacuation simulations of the Pathfinder in case of a fire at a highway service area. It was also analyzed of the difference in RSET by comparing the single or double types of the exit of a facility. The results were as follows. When only one direction exit was opened, all of the RSET were exceeded. When two or more different directions were opened according to the general principle of evacuation, all results met the RSET. The simulations showed that two or more different directions were more shortened in RSET than the one same direction. The result of the types of doors showed that the single type door was shortened in RSET rather than the double type doors. For the evacuation safety in a fire at the highway service areas, firstly, it is necessary to secure two or more exits in a fire at all times. Secondly, the exits should not be same directions. Finally, it is suggested that the exit should be installed with a single type of door.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.133-138
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• 2009

The purpose of this study is to present an alternative plan in order to reduce the required time to flee from the inside of the gosiwon in danger. The data were derived from changing the width of corridors and emergency exits and the number of stairs in the building EXODUS, which is computer simulation program, The analyzed conclusions from the data are following as below (1) Increasing the exits and the number of stairs are efficient to reduce the accumulated time for standing by. (2) Increasing the number of stairs is efficient to decrease the distance to get out of the building to exit. (3) Increasing the number of stairs is efficient to reduce the time to get out of the building to exit.

• Journal of Families and Better Life
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• v.26 no.5
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• pp.75-89
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• 2008

The purpose of this study is to understand the physical accessibility of the child care centers for disabled children in Japan. Fifteen centers located in Tokyo, Japan were surveyed through sketching, measuring, taking pictures, and observation. To understand the user's needs. the directors of the centers were interviewed. As a result,the followings suggestions were proposed. First, when the entrance of the center is close to the road, careful design for the entrance area is required to secure the safety of children using wheelchairs. If possible, a fence or door between the corridor and entrance is necessary. Second, most aspects of accessibility are pretty well designed. But a canopy over the entrance area is required to escape the rain. Third, a wider corridor space is desirable for storing and driving wheelchairs and for special equipment for the disabled. Forth, because the emergency exits were installed but not used, the new and safer emergency exits should be installed. These results will be a good case reference for developing Korean design guidelines for the children with disabilities.