• Journal of Institute of Convergence Technology
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• v.5 no.2
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• pp.33-36
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• 2015

In this paper, the development history of random packings for several generations was briefly introduced. We demonstrate the application of 3D printing to the fabrication of Pall rings, directly using computer aided design (CAD) models. The CAD was used to design Pall rings with different number of blades. The models were then printed by using UV curing of acrylonitrile-butadiene-styrene (ABS) resins. The results show that 3D printing is a promising method for producing precisely controlled packing materials. It is also expected that 3D printing is helpful for the fundamental studies of highly efficient packing materials with complex geometrical shapes.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.370-374
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• 2004

This comparative study means the case studies about not only coalition and partnership but also competition between high speed rail and other transportation modes. Therefore, I reviewed the each case about some countries and tried to develop for making some measurement. However, in this study, some bounds and limits exists owing to the descriptive reviews but not detailed analyses. Hereafter, I am planning to consider the management plan for efficient railway coalition with other transportation at the rail station and other terminal facilities.

• Journal of Korean Society of Transportation
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• v.13 no.4
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• pp.5-29
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• 1995

Advanced Traveler Inoformation Systems*ATIS) , as a subsystem of ITS influence the travel choices of dreivers by providing them with historical, real-time and predictive information to supprot travel decisions and consequently improves the speed and quality of travel. For thesuccessul accomplishment of ATIS, the time-dependent variations of traffic in a road network and travel times of vehicles during their journey must be predicted . The purpose of this study is to evaluate the past developments in the dynamic route choice models and to apply the instantaneous dynamic user optimal route choice model. recently formulated with flow propagation constraints by Ran, Boyce and LeBlanc, to the real transportation network of Seocho-Ku in Seoul. As input data for this application, the time-dependent travel rates are estimated and the link travel time function is derived. The modelis validated from three view points : the efficiency of model itself the ability to predict traffic volume and travel time on links, and the optimal traffic control.

• Journal of Korean Society of Transportation
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• v.12 no.4
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• pp.131-151
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• 1994

An investigation is given to a behavioral analysis of automobile users applying congestion toll theory for the purpose of maintaining the efficiency of transportation system. A case study is performed for the city of Seoul, where modal split behavior of automobile user groups is analysed in various level of congestion toll. Automobile users are grouped with respect to their income levels and work shift times. Automobile user behavior is then explained against the field data. A Logit-type model is applied for modal split changes through the application of congestion toll. It is found in the case study that the users in the monthly income bracket of 1.0~1.5 million won is the most predictable group whose work travel time begins 7:00~9:00 a.m. It is also found in the study that 1,000~1,500 won of congestion toll whould reduce the auto use as much as 5%.

• Journal of Korean Society of Transportation
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• v.5 no.1
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• pp.75-83
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• 1987

The modernistic rationalism which thinks much of the mathematical rationality and economic efficiency is widely spread in Korea economic planning, urban planning, urban transportation planning, and the like. As a result the demands to humanity, amanity, and so on have been disregarded in the name of rationality in urban spatial organization, the typical examples, one of the pedestrian space. The pedestrian space which is passed over easily from the view point of the modernistic rationalism, is actually the space that should be reflected abundantly in urban space. The author emphasized a need of reconsideration on the position of pedestrian space in urban spatial planning process, and adopted the theoretical research on the functions and roles of pedestrian space. In consequence of this study the functions of pedestrian space are considered : the first, the function as a space for moving, the second, the function as a space for buffer. the third, the function as a space for intermediation. the fourth, the function as a space for urban daily life. the fifth, the function as new urban environment-making factor.

• Transactions of Materials Processing
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• v.25 no.4
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• pp.227-234
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• 2016

In the transportation between countries using container, too many empty containers must be transported due to the transportation unbalance. For transportation efficiency, therefore, foldable containers are being developed. Hinge brackets are important parts of foldable containers because great force is applied on the hinges during loading onto and unloading from ships. In this study, the hinge bracket for a foldable container is designed to be made using thick plate or bulk materials to endure the heavy loads. The forming process for the hinge bracket using a thick plate is designed via numerical analysis. First of all, the shape of bracket is designed for the better formability. Bending and successive side wall thickening processes are employed for the forming of the hinge bracket. Maximum thickening that can be achieved in a single stage of forming without a folding defect is determined and three stage of thickening processes are designed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.236-240
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• 2012

Limiting thermal exposure time using rapid thermal processing(RTP) has emerged as promising simplified process for manufacturing of solar cell in a continuous way. This paper reports the simplification of co-firing using RTP. Actual temperature profile for co-firing after screen printing is a key issue for high-quality metal-semiconductor contact. The plateau time during the firing process were varied at $450^{\circ}C$ for 10~16 sec. Glass frit in Ag paste etch anti-reflection layer with plateau time. Glass frit in Ag paste is important for the Ag/Si contact formation and performances of crystalline Si solar cell. We achieved 17.14% efficiency with optimum conditions.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1978-1983
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• 2008

With the increase in population, the area of human activities has expanded, resulting in the dramatic increase in the need for transportation system. Various infrastructures necessary for efficient logistics, however, have not been supplied enough and the logistics efficiency in Korea is in a bad situation now. As a result of the situation, the demand for the railroad transportation system that can provide large volume transportation has increased dramatically. An electric railway system is composed of high-tech subsystems, among which main electric equipment such as motors and converter are critical components determining the performance of electric vehicle. Among the on-board equipments, traction equipment is important part that has influence on safety and performances of vehicles. We is studied for high-speed train of foreign countries. From this research, we knows that axle weight of HEMU-400x is reasonable within 13ton.

• Management Science and Financial Engineering
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• v.13 no.1
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• pp.55-72
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• 2007

We consider the product differentiation model of online channel competition and examine the strategies of hybrid firms in terms of efficiency. After measuring the social cost of online business strategies, we show that (i) online channel of hybrid firm under blockaded entry may increase the social cost if the firms' delivery cost is sufficiently smaller than the consumer's transportation cost, and (ii) online competition under free entry may increase the social cost if the firms' delivery cost is sufficiently larger than the consumer's transportation cost. Finally, we discuss the strategic incentive of hybrid firms to reduce delivery cost and investigate the effect of the Internet maturity on the social cost.

• 한국ITS학회:학술대회논문집
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• 2005.11a
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• pp.83-88
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• 2005

A transportation problem in Korea is a serious issue that has to be solved urgently in the motor era of 15 million vehicles. Recently ITS has been introduced to improve efficiency of the current roads because an excessive budget and a long term construction are needed to build new roads. Therefore the government enacted the law as of ITS and the in architecture. However, these ITS information services were oriented to mainly vehicles and drivers, not public entities such as bus driver, passengers and so on. Nowadays lots of local autonomous city introduced a public transportation information system (PTIS), and providing useful information for the public. For this PTIS, important design issues are to be focused on detecting and tracking technology of moving bus, and a wireless communication link to transmit the location information. This paper presents design models using several wireless communication methods, and an implementation case using a Wireless packet Data communication Network (WDN) to transmit bus location information at Seoul, Korea.