• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.189-192
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• 2021

This study applies a deep learning-based long short-term memory(LSTM) model to track tracking technology. In the case of existing track tracking technology, the weight of constant velocity, constant acceleration, stiff turn, and circular(3D) flight is automatically changed when tracking track in real time using LMIPDA based on Kalman filter according to flight characteristics of an aircraft such as constant velocity, constant acceleration, stiff turn, and circular(3D) flight. In this process, it is necessary to improve performance of changing flight characteristic weight, because changing flight characteristics such as stiff turn flight during constant velocity flight could incur the loss of track and decreasing of the tracking performance. This study is for improving track tracking performance by predicting the change of flight characteristics in advance and changing flight characteristic weigh rapidly. To get this result, this study makes deep learning-based Long Short-Term Memory(LSTM) model study the plot and target of simulator applied with radar error model, and compares the flight tracking results of using Kalman filter with those of deep learning-based Long Short-Term memory(LSTM) model.

• 한국체육학회지인문사회과학편
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• v.58 no.2
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• pp.405-416
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• 2019

This study aimed to identify the efficiency of short track-related sports injury prevention program consisted of muscle strength and neuromuscular training on non-contact injury incidence and characteristics in knee and ankle joints and low back for elite short track speed skaters. Twenty-five short track athletes who belonged to G-City Team were participated in this study from Nov. 2017 to Jul. 2018. Information on their sports injuries occurred were collected and injury prevention program was applied in their warm-up every training sessions and competition. Also their symptom-level of knee and ankle joint and low back were measured by using OSTRC overuse injury questionnaire and Cumberland ankle instability(CAIT). The injury incidence rate after application of prevention program was 2.79 injuries/1,000 hour exposures(HEs), which was lower than before (3.04 injuries/1,000HEs). The OSTRC score (30.89±28.34 and 23.84±23.61, respectively) in knee and low back after application of prevention program were lower than before (58.47±26.77 and 52.36±21.55, respectively), and the CAIT score (13.47±6.07) in ankle joint after application of program was higher than before (16.26±7.28), which means that their symptom-level was alleviated with sports injury prevention program. In conclusion, the sports injury prevention program designed for short track's motion and characteristic can have positive influences on the occurrence of non-contact injury for short track speed skaters.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.3
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• pp.690-696
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• 2013

This study, which is conducted on two groups of skilled people and unskilled people, is purposed to analyze joint angle of lower extremity during short track speed skating in order to find out efficient body position and propose ideal training method. Short Track Speed Skating has a wide range of research areas, but their findings indicate a promising area for further research. Targeting 8 people who are skilled in short track speed skating and 8 people who are not skilled in it, this study analyzes three dimensional images using super-high speed camera to compare differences between these two groups of people. In this study, 6 sections of body positions including right foot push-off, right foot recovery, right foot basic position, left foot push-off, left foot recovery, and left foot basic position were analyzed using 8 super-high speed cameras of VICON. These body positions were analyzed in order to find out joint angles of the hip joint, the knee joint, and the ankle joint. In the section 4 of the inner and outer parts of the left hip angles showed significant difference, and most of the sections of knee joint angles also showed significant difference. In the section 1 and 2 of the plantar flexion, dorsiflexion of ankle joints showed significant difference(p<.001) It was found out that there were differences between groups of skilled people and unskilled people in terms of lower extremity's joint angles such as angles of the hip joint, the knee joint, and the ankle joint.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.683-687
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• 2009

Track jump control is a random access strategy for short distance movement. The most common track jump scheme is a bang-bang control of a kick and brake manner. In a conventional track jump scheme, a track-following compensator is turned off during kick and brake periods, and restarted at a target track for track pull-in. The inevitable controller switching with non-zero initial condition results in undesirable transient response, and excessive overshoot in the transient response causes track pull-in failure. In this paper, a new track jump scheme is proposed for enhancing track jump stability. Instead of control switching, internal states of a track-following controller are artificially manipulated for kick and brake actions in a digital control environment. Experimental results are provided in comparison with conventional track jumps.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.880-885
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• 2004

When a fire takes place, the escape tunnel which could prevent passengers and the crew from disasters would be most important facility among railway tunnel facilities for prevention of disaster. A shorter space between the escape tunnels is much better for safety because of short escape time. The establishment of short space escape tunnels(driftways) in the single track parallel tunnel is much easier. The establishment of long space escape tunnels(inclined shafts, vertical shafts) in the double track is much more advantageous economically. We, therefore, compared the movement time of smog originated from fire with the escape time of the crew and passengers for setting up the best space between the escape tunnels in the double track tunnel. We could calculate the best space between the escape tunnels in the double track tunnel properly by computer simulation.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.580-587
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• 1998

For many decades, the railway was constructed using tracks with jointed rails of relatively short lengths in accordance with rolling and handling technology. The joints cause many drawbacks in the track and lead to significant maintenance cost. So, railroad engineers became interested in eliminating joints to increase service loads and speeds by improving rolling, welding, and fastening technology, Continuous welded rail(CWR) track has many advantages over the conventional jointed-rail track. But in the case of the elimination of rail joints, it may cause the track to be suddenly buckled laterally by thermal and vehicle loads. Thermal loads are caused by an increase in the temperature of railway track. In this paper, CWR track model and CWRB program are developed for linear buckling analysis using finite element method(FEM). The finite element discretization is used with a total of 14 degrees of freedom for each rail element. The stiffness of the fastener, tie, and ballast bed are included by a set of spring elements. The investigation on the buckling modes and temperature of CWR track is presented in the paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.552-559
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• 2011

There is a method for offering continuous information by AF track circuits. Magnetic fields are formed by current through rails in the AF track circuit systems. So, the continuous information is received by the magnetic fields on a on-board antenna. Coating materials of spray on rails are researched to decrease defects such as head check, shelling, corrugation, squats and so on in Germany. Currently, a coating method of rail construction is proposed by using the ceramics in Korea. When deciding physical characteristic of the coating material of spray, researches are required about variation of flux density and resistivity by using the coating material of spray. In case that the flux density is much lower than existing value, the information for train control is not transmitted to the on-board antenna. In this paper, inductance on rails is calculated and a model is presented about variation of the magnetic field intensity and resistivity in the AF track circuit. Standard permeability of the coating material of spray is proposed. Also, standard resistivity of the coating material of spray is presented by analyzing short current.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.109-116
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• 2013

The purpose of this study was to provide fundamental information for the enhancement of performance through kinematic analysis of cornering according to the radius of curve course in short track speed skating. To perform this study, six skaters: three narrow radius players(N, body mass: $56.0{\pm}7.2$ kg, height: $163.7{\pm}5.1$ cm, age: $21.3{\pm}1.5$ yrs) and three wide radius players(W, body mass: $61.0{\pm}9.5$ kg, height: $169.0{\pm}4.4$ cm, age: $20.0{\pm}1.7$ yrs). Three-dimensional motion analysis was performed on the section from the forth block starting to show the change of radius to the sixth block using eight infrared cameras(sampling frequency of 100 Hz for N and W players). The time of push-off was greater for N than for W(p<.05) while the radius of center of mass was greater for W than for N(p<.05). The flexion and extension of knee and hip joint were greater for N than for W(p<.05). The external rotation of left knee joint was greater for N than for W(p<.05). Based on the findings, a small radius by increasing the range of the flexion and extension of knee and hip joint with greater external rotation of left knee joint would be related to more efficient run at curve. It is expected that these results will be useful in developing a training program for enhancing performance of short track speed skating athletes.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.317-324
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• 2007

Until now, the railway has been constructed using track with jointed rails of relatively short lengths to allow thermal expansion in hot summer months. These joints weaken the track structurally and increase track maintenance cost and power consumption of the running train. The CWR(Continuous Welded Rail) Track is the solution of these drawbacks. Although the CWR track not only reduces the track maintenance cost but also increases the life cycle of track components, the stability of the track is highly affected by change of temperatures and vehicle load. A three dimensional nonlinear analysis which considers rail, fastening system and tie has been performed to understand structural behavior of the CWR track. In this case, the translational and rotational stiffness values of fastening system have not been studied. The fastening system makes ties and rails connect. In this study, the stiffness values of various types of fastening systems which consist of clips, rail-pads and insulators are determined by the experiment. The experimental results of the fastening system are compared with the results of parametric study that is performed to investigate the sensitivity of fastening system on stability of CWR track.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.9-18
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• 2018

PURPOSES : In this research, the initiation and development of corrugation on a gravel road with certain wheel and boundary conditions were evaluated using a coupled discrete-element method (DEM) with multibody dynamics (MBD). METHODS : In this study, 665,534 particles with a 4-mm diameter were generated and compacted to build a circular roadbed track, with a depth and width of 42 mm and 50 mm, respectively. A single wheel with a 100-mm diameter, 40-mm width, and 0.157-kg mass was considered for the track. The single wheel was set to run slowly on the track with a speed of 2.5 rad/s so that the corrugation was gradually initiated and developed without losing contact between the wheel and the roadbed. Then, the shape of the track surface was monitored, and the movement of the particles in the roadbed was tracked at certain wheel-pass numbers to evaluate the overall corrugation initiation and development mechanism. RESULTS : Two types of corrugation, long wave-length and short wave-length, were observed in the circular track. It seems that the long wave-length corrugation was developed by the longitudinal movement of surface particles in the entire track, while the short wave-length corrugation was developed by shear deformation in a local section. Properties such as particle coefficients, track bulk density, and wheel mass, have significant effects on the initiation and development of long-wave corrugation. CONCLUSIONS : It was concluded that the coupled numerical method applied in this research could be effectively used to simulate the corrugation of a gravel road and to understand the mechanism that initiates and develops corrugation. To derive a comprehensive conclusion for the corrugation development under various conditions, the driver's acceleration and deceleration with various particle gradations and wheel-configuration models should be considered in the simulation.