• Proceedings of the KSR Conference
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• 1998.11a
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• pp.345-352
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• 1998

The dynamic analysis of a train system has tended to analyze one vehicle or subsystem of that rather than to analyze entire vehicles. But, the speeding and lightening of a train requires more accurate analysis. Thus, the analysis of entire vehicles is required but it spends much time. Therefore, it is needed to find out the new analytic method which is more accurate and efficient. This paper suggests a new method for analyzing a multi-vehicle system more efficiently, using‘mechanical impedance’At first, get the impedance of vehicles which influence the dynamics of the object car, through analyzing the dynamics of a vehicle. ‘Equivalent system’, a simple mechanical system, of which the impedance is similar to that ,is proposed. Then, the equivalent system was applied to a vehicle and it showed that the equivalent system works like a real vehicle system. Finally, we tried non-linear analysis of a vehicle to which the equivalent system is applied.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.41-43
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• 2015

Urban Informatics, the application of data science methodologies to the urban development and planning domain, has been increasingly adopted to improve the management and efficiency of cities. This paper introduces state of the art use cases in major cities including New York, London, Seoul and Amsterdam. It also introduces recent advances in using Big Data by multi-lateral institutions for poverty reduction, and startups utilizing open data initiatives to create new value and insights. Preliminary research performed on using Seoul's open data such as building permit data and health code violations are also introduced to demonstrate opportunities in this relatively new but promising area of research.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.812-817
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• 2011

Rolling stocks are often subjected to the effects of natural cross wind or train wind pressure due to the crossing train. These wind pressure cause the falling-off in running stability and turnover problem. It is sometimes reported that trains are blown over by a gust of wind in overseas. So, many countries enact regulations to secure the safety for wind speed. In this study, we analyzed the difference between the regulation for turnover safety of train which was enacted by Ministry of Land. Transport and Maritime Affairs and that based on the multi-body model. In case of multi-body model, it is assumed that the degrees of freedom for carbody and bogie are assigned an independent values respectively. The results show that the latter approach based on multi-body model can access the safety of turnover and replace the computational method which is accessing with lateral force, derailment coefficient and decrement of wheel load.

• Korean journal of communication and information
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• v.56
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• pp.219-236
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• 2011

Since the end of the $19^{th}$ century, Korean English-language newspapers have been published in Korea to inform readers about Korea and Korean people's point of view concerning world problems. Among them was the Korean Republic (KR), the former name of the Korea Herald, founded on August $15^{th}$, 1953 (Korean Liberation Day from Japanese colonial rule). This newspaper was started especially to report on international affairs, just after the Armistice agreement was signed on July $27^{th}$, 1953, at the initiative of the first president of the Republic of Korea, Syngman Rhee. He vehemently expressed his and the Korean people's opinion about Korean problems in world politics where big powers were dominating and deciding small countries' destinies. This paper is written to show that Korean English-language newspapers were used as tool of public diplomacy not only for the readers of target countries but also for Korean readers, well before the media diplomacy theory became popular several decades later. In the deplorable world situation where Korea was colonized and divided into halves by the wills of the super powers, the Korean media participated actively via dialogue in English to solve the Korean problem. This paper studies the editorials of the KR for one year, the year just after its foundation. Vis-a-vis the United States, the KR defended its political system of free democracy by insisting on the Korean people's hopes, the reunification of the peninsula and acquiring American assistance in economic and military areas. Regarding Japan, Korea had doubt about its expansionist policy by way of rearmament. First, the Korean government tried to defend its territorial waters, including Dokdo Island. As for multi-lateral relationships, Korea was concerned about the spread of communism to its territory in the world where socialism was dominating.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.69-72
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• 2008

The so-called Pier-Shafts system which consists of the continuous column and shaft is often used to support the highway bridge structure because of advantages in easy construction and low cost. In the earthquake region, the Pier-Shafts system undergoes large displacements and represents a nonlinear behavior under the lateral seismic loading. The soil-pile interaction should be considered for more accurate analysis of the Pier-Shafts system. In this study, a transverse response of a reinforced concrete Pier-Shafts system inside multi-layered soil medium is predicted using a finite element program which adopts an elasto-plastic interface model for the interface behavior between the shaft and the soil. Then, seismic analysis is performed to evaluate the performance of Pier-Shafts system under strong ground motion and their results are verified with experimental data.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.283-290
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• 2007

A bi-modal tram has been developed to offer an advanced transportation service compared with existing vehicles. The All-Wheel-Steering system is applied to the bi-modal tram to satisfy the required steering performance because the bi-modal tram has extended length and articulated mechanism. An ECU for the steering system is essential to steer wheels on 2nd and 3rd axles by the specific AWS algorithm with the prescribed driving condition. The Hardware-In-the-Loop Simulation(HILS) system is planned for the purpose of evaluating the steering system of the bi-modal tram. There are kinematic links with the hydraulic actuator to steer wheels on each 2nd and 3rd axles and also same steering mechanism as the actual vehicle is in the HILS system. Controlling the movement of hydraulic actuator which reflects the lateral steering reaction force on each wheel is the key to realize the HILS system, but the reaction force is continuously changed according to various driving conditions. Therefore, the simulation through the multi-body dynamics model is used to obtain the required forces.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.254-260
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• 2000

The spacer grid is one of the main structural components in fuel assembly, which supports the fuel rods, guides cooling water, and protects the fuel assembly from the external impact load such as earthquakes. The nonlinear dynamic impact analysis is conducted by using the finite element code ABAQUS/Explicit. Boundary condition for dynamic analysis is well applied to the test condition. Simulation results also similarly predict the local buckling phenomena. In addition to the buckling parameter, the local buckling cause is examined by both simulation and test method. It is found to correspond well with the test results. Impact tests are also carried out for some specimens of the spacer grid in order to compare the results between the test and the simulation. This test is accomplished by a free fall dummy weight onto the specimen. From this test, only the uppermost and lowermost layers of the multi-cell are buckled, which implies the local buckling at the weakest point of the grid structure.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.402.1-402.1
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• 2014

Photonic force microscopy (PFM) is an optical tweezers-based scanning probe microscopy, which measures the forces in the range of fN to pN. The low stiffness leads proper to measure single molecular interaction. We introduce a novel photonic force microscopy to stably map various chemical properties as well as topographic information, utilizing weak molecular bond between probe and object's surface. First, we installed stable optical tweezers instrument, where an IR laser with 1064 nm wavelength was used as trapping source to reduce damage to biological sample. To manipulate trapped material, electric driven two-axis mirrors were used for x, y directional probe scanning and a piezo stage for z directional probe scanning. For resolution test, probe scans with vertical direction repeatedly at the same lateral position, where the vertical resolution is ~25 nm. To obtain the topography of surface which is etched glass, trapped bead scans 3-dimensionally and measures the contact position in each cycle. To acquire the chemical mapping, we design the DNA oligonucleotide pairs combining as a zipping structure, where one is attached at the surface of bead and other is arranged on surface. We measured the rupture force of molecular bonding to investigate chemical properties on the surface with various loading rate. We expect this system can realize a high-resolution multi-functional imaging technique able to acquire topographic map of objects and to distinguish difference of chemical properties between these objects simultaneously.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.225-230
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• 2009

From the view point of railway vehicle dynamics, the interaction between wheel and rail have an huge effect on the behavior of the vehicle. This phenomenon is an unique motion, only for railway vehicles. Furthermore, close investigation of the backgrounds of the interaction is the key to estimate the dynamic behavior of the vehicle, successfully. To evaluate the model including flexible bodies such as car body and catenary system of the next generation express train, it is necessary to develop proper dynamic solver including a wheel rail contact module. In this study, wheel-rail contact module is developed using the general purpose dynamic solver. First of all, the procedure for calculation of the wheel-rail contact force has been established. Generally, yaw angle of the wheelset is ignored. Sets of information are summarized as tables and splined for further uses. With this information, normal force and creep coefficient can be extracted and used for FASTSIM algorithm, which has been shown good reliability over years. Normal force and longitudinal, lateral force at the contact surface are also calculated. Those data are verified by commercial railway simulation program 'VAMPIRE'. This procedure and program can offer a basic process for estimation of the dynamic behavior and wear of the wheel-rail system, even while running on the curved rail. Finally, multi-dimensional inspection tool will be developed including the prediction of the derailment.

• Proceedings of the Ginseng society Conference
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• 2005.11a
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• pp.3-18
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• 2005

This paper reports the characteristics of 8 new cultivars for selected from Korean ginseng. The occurance of multi stems were the highest in Yunpoong(45%) and the lowest in Gumpoong(7%), but growth of aerial parts were the highest in Gumpoong and the lowest In Yunpoong among new cultiyars. The ratio of seeds harvest were the highest in Gumpoong(85.4%) and the lowest in Chunpoong(69.1%), but number of seeds per plant were the highest in Yunpoong(108.3ea) and the lowest in Chunpoong(77.5ea) among new cultivars. The ratio of leaf burning were the highest in Chunpoong but the lowest in Yunpoong among new cultivars. In weight distribution of the different parts of the ginseng roots, the ratio of main root were high in Jakyungjong(63.1%) but low in new cultivars(49%-55.9%), but the ratio of lateral root were high in new cultivars(19.3-23.3%), but low in Jakyungjong(13.2%), the ratio of fine root were not different. Root yield declined in the order of Yunpoong, Gumpoong, Gopoong, Chunpoong, Sunpoong, Jakyungjong. The length of main root were the longest in Chunpoong(8,0cm) but the shortest in Yunpoong(6,4cm), The ratio of rusty-root was low in new cultivars(0,2-9,5%), but high in Jakyungiong(16,3%). The grade of red ginseng roots decreased in the order of Chunpoong, Gumpoong, Gopoong, Sunpoong, Yunpoong, Cheongsun, Jakyungjong. The total ginsenoside contents per dry weight in main roots was high in Gumpoong(8.53mg), Yunpoong(8.13mg), Gopoong(7,47mg), but low in Chunpoong(5.73mg), Sunpoong(4.87mg).