• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 봄 학술발표회 논문집
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• pp.191-198
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• 1994

The nonlinear dynamic behaviors of guardrail established on the local or high way have been investigated using BARRIER Ⅶ program with respect to four design variables such as section type of beams and posts, impact angle, impact velocity and vehicle weight. Computer simulation programs are sophisticated analytical models for analyzing dynamic vehicle/barrier interactions and provide a relatively inexpensive alternative to full scale crash testing. This study has been focused on the structural adequacy, occupant risk, and vehicle trajectory. For this purpose, the maximum deflection and impact force have been calculated to design the clear zone and to analyze effect of impact attenuation. Also, the acceleration of vehicle and exit angle after collision have been computed to estimate the occupant risk. From this study, it is suggested that we should strengthen the design criteria of guradrail to prevent from disastrous traffic accidents.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.318-321
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• 2005

Crashworthy design of a train is a systematic approach to ensure the safety of passengers and crews in railway transportation for the prescribed accident scenarios. This approach needs new structural arrangements and designs to absorb higher levels of impact energy in a controlled manner and interior designs to minimize passenger injuries. In this paper, an evaluation method for crashworthiness of Korean tilting train express is introduced. Crush characteristics for each part of tilting train express are evaluated numerically through 3-dimensional shell element analysis with LS-DYNA. Based on a head-on collision and a level crossing collision scenarios, the crash behaviors of tilting train express are evaluated numerically using full-rake collision simulations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.903-908
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• 2007

A retractor is the major component of a seatbelt system that restraints passengers by locking the movement of webbing. Recently, in order to increase the effectiveness of seatbelt systems, motorized retractors that remove slack and correct passenger posture just before airbag expansion when collision is predicted are widely used. Key component of motorized retractors is the one-way clutch that engages and disengages the winding action of webbing according to the direction of motor revolution. Analytical investigation of action of the one-way clutch mechanism has been carried out to figure out conditions for one-way locking, and to study the effect of various kinematic and dynamic design variables of one-way clutch. Using combination of ADAMS and LifeMOD soft-wares, dynamic simulation of operation of motorized retractors including Hybrid-III dummy model has been carried out to evaluate the performance of the motorized retractors in various crash scenarios.

• 대한안전경영과학회지
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• 제10권3호
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• pp.63-71
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• 2008

This study was conducted with respect to the causal factors revealed through the investigation of the recent airlines aircraft crash accident which occurred while aircraft was on the climb-out or on the final approach. This study also highlighted the importance of flight deviation and exceedance occurrences in consideration of Flight Operational Quality Assurance Program(FOQA). Twenty airline pilots participated in the flight experiment to perform ten(10) sets of simulated approaches and landings. As a result, Twelve(12) kinds of deviation events were discovered. In this respect, The FOQA program must be fully implemented to prevent any flight safety incident under the auspices of the Korea domestic aviation community as well.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.235-242
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• 2000

The most important technology to improve crashworthiness of high speed trains is to design their front structures to absorb crash energy easily. In this paper, crashworthy designs of the front structures in KTX and KHST are compared by numerical simulation under SNCF accident scenario. Furthermore, to evaluate their crashworthiness tinder a typical real situation, the power cars are simulated for the accident collided against a deformable dump truck of 15 tons at 110 kph. The front structure of KHST, finally designed, shows a good crashworthy characteristics. Finally, the impact strength of coupling components is evaluated by analyzing a consist of the front three KHST units under scenario of train-to-train collision at 30 kph.

• 한국도로학회논문집
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• 제14권5호
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• pp.145-155
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• 2012

PURPOSES: This study proposes a novel method based on microscopic simulation models to evaluate bicycle passing ways in mixed traffic flow conditions at signalized intersections. METHODS: Both operational efficiency and safety are taken into consideration in the evaluation. A widely used performance measure, delay, is used for evaluating the operational efficiency. Regarding the safety evaluation, surrogate safety measures (SSM) to represent traffic conflicts and the level of crash severity, DeltaS and Max.DeltaV, are applied in the proposed method. RESULTS: Extensive simulations and statistical tests show that an integrated bike-box way is identified as the best in terms of operational efficiency and safety. CONCLUSIONS: The proposed method and outcomes of this study will be valuable for bicycle traffic operations and facility design.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.652-656
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• 2004

Crashworthy design of trains is now indispensable procedure in modern railway vehicle design for ensuring the safety of Passengers and crew. It is now widely recognized that a more strategic approach is needed in order to absorb higher level energy in a controlled manner and minimize passenger injuries effectively. The first design step in this strategic approach is the design of the front end structure(so called HE extremities) to absorb a large part of total impact energy and then the structure of passengers non-accommodation zones(so called LE extremities) is designed to absorb the rest of impact energy. In this paper, the passengers entrance door area is selected as the LE(low energy) extremities and the design of the LEE was carried out. The main part of LEE design procedures is the design of energy absorbing tubes. For this purpose, the several tube candidates are introduced and compared to each others with numerical crash simulation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.385-392
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• 1998

Train crashes involve complex interaction between deformable bodies in multiple collisions. The purpose of this study is to suggest the effective analytical procedure using simple model for the crashworthiness of motorized trailer of high speed train. The simple model, with very short modeling time and reduced computation time was adopted to extract the global behaviour and to perform a pre-optimization of the considered structure. Firstly, various types of crash events are investigated and the conditions for numerical simulation are defined. The simple model, using the beam and non-linear spring element, and shell element model are used to evaluated energy absorption and deformation mechanism in analyses. And aluminum is applied to real model after verification with square tube analyses. Finally, loading path and energy absorption of main components are evaluated. The analyses are aimed to ensure the crashworthiness design of high speed train.

• Journal of Information Processing Systems
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• 제8권2호
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• pp.263-278
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• 2012

The data grid provides geographically distributed resources for large-scale applications. It generates a large set of data. The replication of this data in several sites of the grid is an effective solution for achieving good performance. In this paper we propose an approach of dynamic replication in a hierarchical grid that takes into account crash failures in the system. The replication decision is taken based on two parameters: the availability and popularity of the data. The administrator requires a minimum rate of availability for each piece of data according to its access history in previous periods, but this availability may increase if the demand is high on this data. We also proposed a strategy to keep the desired availability respected even in case of a failure or rarity (no-popularity) of the data. The simulation results show the effectiveness of our replication strategy in terms of response time, the unavailability of requests, and availability.

• 자동차안전학회지
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• 제5권1호
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• pp.25-30
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• 2013

The main purpose of this research is to predict dynamic behavior of door locking system for side impact safety and the design process to avoid door opening is introduced. The equations of motion that represent the system are obtained from the energy equation. From them, the motion of door handle is predicted by using Runge-Kutta $4^{th}$ order method and the simulation result is compared with the real crash data. Also, the design guide to define the properties of door locking system from the standpoint of avoiding door opening phenomenon is introduced.