• Journal of Mechanical Science and Technology
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• v.16 no.6
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• pp.776-784
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• 2002

We have performed experimental studies for the improvements of pneumatic brake systems of freight trains. Currently, most of the freight trains operated by the Korean National Railroad have either empty-load or diaphragm type brake systems. In this study, appropriate methods that the air pressure characteristics in both type of brake systems are in accordance with each other have been investigated. We have also performed running tests using a 30 car-train set to design optimum capacity of a quick release valve. The test results show that the quick release valve is considerably effective in shortening the release time of the diaphragm type brake system. In the case of a normal brake application, the diaphragm type brake system with the quick release valve reduces the release time to 34% of that of the system without the quick release valve. This release time is almost equivalent to that of the empty-load type brake system. Accordance of braking performance in different types of brake systems in a train set is expected to prevent wheel flats and to reduce maintenance costs.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.776-780
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• 1989

A constant torque dynamometer with associated instrumentation and control functions for the development of friction materials for automotive-type disc brakes, has been developed. Full scale disc pads are subject to a series of intermittent brake applications at a constant rotational speed of the brake disc and constant braking power. This paper gives a description of the dynamometer and an example of results obtained.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.120-124
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• 2004

Computer aided simulation is an essential part in planning, design, and operation of railway systems. To determine the adequate performance and specification of railway system, it is necessary to calculate train performances such as distance, speed, power during train's running. This paper presents result of train performance simulation using the program that developed for Korea high speed train. To verify result of simulation, we have compared that with experiment data.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.64-66
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• 1997

The LHSM is the combined electromagnetic propulsion and levitation, braking and guidance system for Maglev. In this paper, the LHSM has the figure-of-eight shaped $3{\phi}$ armature windings, the field winding, and segmented secondary having transverse bar track. we treat of the development - design, analysis - of a combined electromagnetic propulsion/levitation systems, LHSM.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.308-315
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• 2000

Headway calculation is a important mean to evaluate railway system performance. A accurate headway calculation can be needed to headway reducing being achieved line capacity increasing by regulating signals spacing without any line construction. This paper introduced the theories and algorithms of calculating headways on wayside, multi step, one step braking and moving block signalling systems and showed some results of headways.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.423-427
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• 2003

In this paper, it is to development of brake system with ABS function for aircraft. The test of brake system is required before applying on aircraft. The real-time dynamic simulator with 5-D.O.F. aircraft dynamic model is developed for braking performance test of ABS (Anti-skid Brake System) control h/w with anti-skid brake functions. The dynamic simulator is real-time interface system that is composed of dynamic simulation parts, master control parts, digital and analog in/out interface parts, and user interface parts. The 5-D.O.F. aircraft dynamic model is composed of a big contour and a little contour by simulation s/w. The big contour represents the interactions of forces in airframe, nose and main landing gear, and engines on the center of gravity. The little contour represents interactions of wheel, braking units, hydraulic units and a control unit. ABS control h/w unit with ABS control algorithm is also developed and is tested with simulator under the some conditions of gripping coefficient. We have known that ABS control h/w unit on wet or snowy runway as well as dry runway very well protects wheel skid.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2080-2093
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• 2008

Disk brake system take charge of maximum braking energy among the mechanical brake systems for high speed train. For this reason, Metallic friction materials and heat resistant steel disk is adopted at disk brake system for high speed train. It was investigated tribological characteristics(friction coefficient, friction stability, wear rate and braking temperature) between some kinds of metallic friction materials and heat resistant steel disk. Cu-based friction material for high speed train have suitable tribological characteristics.

• Journal of Auto-vehicle Safety Association
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• v.9 no.2
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• pp.13-19
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• 2017

This paper presents safety assessment scenarios for cyclist autonomous emergency braking(AEB) system. To assess the safety performance of AEB in real traffic situation with limited number of scenarios, scenario should reflect the characteristics of real traffic collision cases. For this, statistic data of real traffic car-to-cyclist collision in Korea are analyzed. Many types of accidents are listed and categorized based on the movement of vehicle and cycle just before the collision. Then, the characteristics, main issues and limitations of each scenarios are discussed. Not only the test scenario itself but also the cost and time for the test are very important issues for the test scenarios to actually repeat the test for various systems. Also, the performance of AEB can be effected by the algorithm of AEB and the technical limitation of the sensors and hardwares. Therefore, required number of tests, possibility of dummy destruction and other technical issues are discussed for each scenarios. Based on these information, typical scenarios are selected. Also, using this information, vehicle speed range, cyclist speed and collision point are established. Proposed scenarios are verified and modified based on the vehicle test results. vehicle test was evaluated 5 times for each scenarios. Based on this results, final test scenarios are modified and proposed.

• Journal of Auto-vehicle Safety Association
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• v.11 no.1
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• pp.7-16
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• 2019

There are trying to reduce damage from automobile accident in many countries. In many automobile companies, there have been active study on development of ADAS (Advanced Driver Assistance Systems) for commercialization, in order to reduce damage from automobile accident. ADAS is the system providing convenience and safeness for drivers. Generally, ADAS is composed of ACC (Adaptive Cruise Control), LKAS (Lane Keeping Assist System), and AEB (Autonomous Emergency Braking). AEB of the ADAS, it is an autonomous emergency braking system and it senses potential collide and avoids or degrades it. Therefore AEB plays a significant role in reducing automobile accident rate. However, AEB safety evaluation method is not established not yet. For this reason, this study suggests safety evaluation scenarios with adding cut-in, sensor malfunctioning scenario that scenario domestic street conditions considered as well as original standard AEB scenario of Euro NCAP for establishment of safety evaluation method of AEB. And verifying validity of suggested scenario by comparing the calculated values of the theoretical formulas presented in the previous study with results of the actual vehicle test.

• Journal of Auto-vehicle Safety Association
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• v.15 no.3
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• pp.59-65
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• 2023

As advanced driving assistance system (ADAS) and autonomous driving performance continue to improve, existing crash accidents and crash types are changing. Accordingly, the collision angle and the seating posture of the occupant are changed. It is necessary to study how the occupant injury mechanism changes according to these different crash types. In this regard, a representative crash test mode was derived when the automatic emergency braking system (AEB), one of the autonomous driving performance, was applied to the representative car-to-car crash scenario in Korea. The derived crash test mode was used to analyse the mechanisms of collision injuries according to both impact angle and the occupant seating posture (reclined seat-back angle). The results obtained through this study can be utilized as reference data for the development of new crash evaluation methods and improvements in crash restraint systems for enhancing crash safety.