• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1058-1064
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• 2004

As one of reinforcing methods for soft roadbed, the problems that mud-pumping and settlement occurred by soft roadbed, were investigated, evaluated and analyzed through installing relatively economical and efficient geosynthetics on the selected track-bed for testing. Mock-heang to Dong-ryang on the filed resting sections in the Chung-buk lines were selected as investigating the state of track and prepared field after selecting three of 1,700 spots which often make mud-pumping and requiting maintenance for that. Long curved line radiuses(R) of Mock-heang to Dong-ryang are 500m that were installed with 4 types of geosynthetics layers and one ballast layer. Installed testing cross-section is 200m totally with 40 m between places. Strength or prepared roadbed was measured to investigate the state of roadbed and track with constructing(installing) field testing sections and physical properties of roadbed soils were evaluated and analyzed. Also, mud-pumping, settlement of elastic or plastic sleeper, failure or track, wheel-loads, transverse and earth pressures were measured after installing field testing sections.

• Journal of the Korean Society for Railway
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• v.10 no.3 s.40
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• pp.271-277
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• 2007

The Korean Tilting Train eXpress (TTX) development program is in progress for the purpose of running speed or passenger's comfort improvement at the curved track. However, the speed up and light weight of train make poor the dynamic safety of the TTX in strong cross wind. In this paper, 3-dimensional numerical analysis on the flow field around the TTX under strong cross wind is performed for each operating condition, such as the train speed, cross wind speed, tilting/nontilting condition, and so on. Due to the strong cross wind, the pressure distribution around the train becomes asymmetric, especially at the leading car. Asymmetrical pressure distribution causes the side force and strong unstability. The side force on the train is proportional to the train speed and cross wind speed. Based on the numerical results, the overturning coefficients are predicted for investigation of the train stability, and all of them are less than the critical value, 0.9. The results in this study would be a good data for providing importance to judgement of cross wind safety of TTX.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.508-518
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• 2016

In this paper, we propose a method combining an accelerometer with a cross structured light system to estimate the golf green slope. The cross-line laser provides two laser planes whose functions are computed with respect to the camera coordinate frame using a least square optimization. By capturing the projections of the cross-line laser on the golf slope in a static pose using a camera, two 3D curves’ functions are approximated as high order polynomials corresponding to the camera coordinate frame. Curves’ functions are then expressed in the world coordinate frame utilizing a rotation matrix that is estimated based on the accelerometer’s output. The curves provide some important information of the green such as the height and the slope’s angle. The curves estimation accuracy is verified via some experiments which use OptiTrack camera system as a ground-truth reference.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.237-245
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• 2007

GB-SAR (Ground-Based Synthetic Aperture Radar) system is an imaging radar that obtains high resolution 2-D image through a synthetic aperture effect from the accurate linear-motion control of antenna on the ground. The highly versatile system configurations and accurate repeatability of GB-SAR operation allow one to accurately monitor the stability of surface scatterers with millimeter accuracy by SAR interferometry. In this paper we introduce the development of a GB-SAR system and show the possibilities of SAR polarimetry and interferometry such as DInSAR, Cross-Track InSAR, Delta-f InSAR, and PSInSAR.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.682-684
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• 2002

There is much room for consideration that the magnet design of UTM. When the vehicle runs 60mR curved line on test track, the ratio of cross section area changed to cross the magnet pole and rail. The ratio is reduced about 20% of the total magnet on one bogie. Therefor, magnet current is increased about 3.5A to maintain constant air gap. This paper suggest to margin of the magent design is 1.1 rather than rated levitation force.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.50-56
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• 2015

In this study, AISI M2 powder was selected primarily through various pieces of literature in order to improve the hardness and wear resistance. Among the laser metal deposition parameters, laser power was studied to improve the deposition efficiency in the laser metal deposition using a diode-pumped disk laser. An SKD61 hot work steel plate and AISI M2 powder were used as a substrate and powder for laser metal deposition, respectively. Experiments for the laser metal deposition were carried out by changing the laser power and track layer. The quality of the track surface and cross-section after applying the single-layer method was better than that obtained from applying the multi-layer method. As the laser power increased, the track thickness was increased, and the surface roughness deviation was decreased. In laser power condition of 1.6kW, the maximum hardness of the deposition track was 790Hv. This value was 40% better than the hardness of the SKD61 after heat treatment.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.2010-2016
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• 2009

Before introducing high speed train, train signal system was operated passively depending on a driver by signal lamp display. Now it is changing to onboard signaling system because of train speed increased(conventional track is 230km/h, high speed track is 380km/h), high speed. low speed freight train operation mixed, operation for high speed train in conventional track and dense operation. ie. ETCS(European Train Control System) Level 1 is introducing. Also, in case of high speed train, the train control system of France was introduced and has operated from 2004, now we have a difficulty for rising speed more than 300km/h because of commercial operation speed limited as 300km/h. Therefore, it need to establish the train control technique according to trackside surroundings and develope standard system like European ERTMS/ETCS, China CTCS(Chinese Train Control System), Japan D-ATC(Digital Automatic Train Control). In this paper, we derive the systematization method for Korea train technique by network-oriented, information-oriented, intelligence-oriented and combination-oriented corresponding train development direction. Proposed method has a merit to prevent cross by mixed operation with existing system and improvement after validity demonstration and system development and supply train system to meet user requirement in exporting.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.4
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• pp.37-43
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• 2019

Obstacle limitation surfaces are imaginary space surfaces that must be clear of obstacles for the aircraft to safely take off and land on the aerodrome. These surfaces are closely related to the safety of the VFR aircraft, which require a pilot to be able to see outside the cockpit, to control the aircraft's altitude, navigate, and avoid obstacles and other aircraft. The Republic of Korea, which has a lot of restrictions on the use of airspace, cannot provide a rich operating environment for VFR aircraft. Under these circumstances, safer operation will not be guaranteed if additional factors that directly or indirectly affect existing VFR routes, such as drone delivery services. This study analyzes and models the track distribution of each VFR section based on radar track data around a specific airport. Through this study, we estimate the three-dimensional space for VFR aircraft and provide the data for future research such as airspace analysis of VFR corridors and correlation with obstacle limitation surfaces.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.412-419
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• 2011

With an increase in rail traffic, developing activities around structures of railway have been expanded. Inevitably, the changes to cross though sub-structures of railway have been getting increased. However, this situation affects on the safe operation of trains. Generated wheel load makes on the result in settlement on roadbed and damages on track materials. Therefore, via the numerical analysis were carried out for the box structure and subground using FEM analysis program called. Visual FEA/Geo 4.19. Parametric studies were performed by changing soil depth above box structure constructed in railway embankment. A standard live load was applied to simulate loads from train. Through this study, a minimum required soil depth above subground box structure was recommended based on deformation and stresses in concrete railway system.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.117-124
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• 2000

This paper presents the construction planning and the detail design of a 16.2 km long railroad tunnel in a mountainous area. Major design conditions for railroad are the single track, loop-typed alinement, and a maximum grade of 24.5$\textperthousand$. A underground station(double track) with a length of 1.1km is located in the middle of the line for train cross-passing. Tunnel is excavated in highly complex geological conditions including faulted areas, abandoned mine works areas, and various rock types such as sandstone, shale, limestone, and coal seam partly. Drilling and blasting method was adopted because it is more flexible than TBM(Tunnel Boring Machine) as a result of risk assessment for geological conditions in this area. Two working adits were planned to adjust the construction schedule and can be used for ventilation and maintenance in operation phase. New material and concept were introduced to the tunnel drain design. They are expected to improve tunnel drain condition and capability. Rational tunnel support design was tried to consider the various tunnel size and purpose and to use the geological investigation results.