• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.64-69
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• 2012

Head injury is one of the most common cause of deaths in car-to-pedestrian collisions. To reduce the severity of such injuries, many international safety committees have performed headform impact test for pedestrian protection. In this paper, an adult headform impactor model is developed based on the finite element (FE) method and validated through the numerical simulation. The skin material of headform impactor is known as polyvinyl chloride skin (PVC) and its material was assumed as viscoelastic. The viscoelastic parameters of headform skin are identified by a series of trial and error methods. The new developed FE adult headform impactor is verified by the drop test and FE JARI adult headform impactor provided by Madymo program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.968-972
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• 2007

The importance of bumper system lies not only in the styling of vehicles, but also in the protection of vehicles and pedestrians from reasonable impact. In this study, we proceed to search a method for efficient bumper system without using the impact test and the computer simulation to analyze the bumper system. In the process of the research, we proposed the each method that is used to search the shape that satisfy each regulations in first, because bumper's dimensions to satisfy 'vehicle protection' regulations and form's dimensions to satisfy ‘pedestrian protection' regulations are difficult to exist together. After that we proposed the calculate method and design algorithm that is used to search a reasonable point satisfying the two regulations together.

• Wind and Structures
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• v.11 no.1
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• pp.51-70
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• 2008

CFD is applied to evaluate pedestrian wind comfort at outdoor platforms in a high-rise apartment building. Model validation is focused on generic building sub-configurations that are obtained by decomposition of the actual complex building geometry. The comfort study is performed during the design stage, which allows structural design changes to be made for wind comfort improvement. Preliminary simulations are performed to determine the effect of different design modifications. A full wind comfort assessment study is conducted for the final design. Structural remedial measures for this building, aimed at reducing pressure short-circuiting, appear to be successful in bringing the discomfort probability estimates down to acceptable levels. Finally, the importance of one of the main sources of uncertainty in this type of wind comfort studies is illustrated. It is shown that the uncertainty about the terrain roughness classification can strongly influence the outcome of wind comfort studies and can lead to wrong decisions. This problem is present to the same extent in both wind tunnel and CFD wind comfort studies when applying the same particular procedure for terrain relation contributions as used in this paper.

• Journal of the Korea Society for Simulation
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• v.25 no.3
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• pp.41-51
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• 2016

In this study, we propose an improved Floor Field Model(FFM) that considers the physical characteristics of pedestrians, i.e., body size, shape, and posture. Also we analyse limits of FFM and features of improved model compared with existing evacuation simulation models. FFM is a typical microscopic pedestrian model using CA, but it does not reflect the physical characteristics of pedestrians. Because of this, FFM is difficult to modeling phenomena such as collision, friction between pedestrians. As a result, FFM calculates a very short evacuation time when compared with the other models. We performed a computational experiment to compare improved model with other models such as FFM, Simulex, Pathfinder in an actual campus building. We carried out a comparison of evacuation aspect according to the change in number of evacuees. Also we compared evacuation aspect by exit. Finally, we confirmed that improved model reflects physical phenomena which were not reflected in FFM. Especially, experimental results were very similar to the Simulex.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.451-462
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• 2014

In this paper, Coordinated Semi-Actuated Signal Control algorithm was developed and evaluated. According to the analysis of simulation, the coordinated semi-actuated signal control led to reduced vehicle delay as the difference of traffic volume between major and minor streets was getting bigger. But when there was relatively high traffic volume, or the equivalent amount of traffic volume on major and minor streets, optimized pre-timed signal control was verified to lower delay times compared to coordinated semi-actuated signal control; however, it might increase pedestrian delay. Therefore, the coordinated semi-actuated signal control should be implemented at intersections where traffic volume is relatively low.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.115-121
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• 2012

In spite of serious injuries caused by traffic accidents of car-pedestrian, the dispute is constantly occurring and economic losses and mental suffering is escalating since the cause of accidents is not scientifically identified. This study reviewed vehicle dynamics, driving dynamics, collision dynamics, traffic and road engineering for traffic accidents analysis based on traffic accidents related physically objective evidence and analysed the cause of accidents by getting results which applied vehicle initial collision velocity before collision, processing trajectory, collision stance, vehicle velocity before & after collision and parameter by using PC-Crash program. I found that skid mark and collision velocity of car-pedestrian had the error of 11.2%, 2,27% compared to theoretical values.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.2
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• pp.23-29
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• 2012

Existing pedestrian and evacuation models generally seek to find locally optimal solutions for the shortest or the least time paths to exits from individual locations considering pedestrian's characteristics (eg. speed, direction, sex, age, weight and size). These models are not designed to produce globally optimal solutions that reduce the total evacuation time of the entire pedestrians in a building when all of them evacuate at the same time. In this study, we suggest a globally optimal model for indoor pedestrian evacuation to minimize the total evacuation time of occupants in a building considering different distributions of them. We used the genetic algorithm, one of meta-heuristic techniques because minimizing the total evacuation time can not be easily solved by polynomial expressions. We found near-optimal evacuation path and time by expressing varying pedestrians distributions using chromosomes and repeatedly filtering solutions. In order to express and experiment our suggested algorithm, we used CA(cellular automata)-based simulator and applied to different indoor distributions and presented the results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.1-12
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• 2020

In this study, the effect of the social distance maintenance and pedestrian route system was analyzed for Seoul Station, one of the multi use facilities according to the COVID-19 pandemic. For analysis, the Seoul Station pedestrian network was established through the survey of the number of passengers and CAD floor plan. A pedestrian that maintaining Social Distance was implemented using the Social Force Model. Based on this, scenario analysis was proceed. As a result, when the walking line system was installed the average walking speed decreased compared to the current situation. but the average density was analyzed that maintain the walking level of service (LOS)'C', this mean walking line system is effective, and the effect of the walking line system was proved. It can be used as a pedestrian simulation model.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.79-85
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• 2011

The problem of evacuating pedestrians from a room or channel under panic conditions is of obvious importance in daily life. In recent years, several computer models have been developed to simulate pedestrian dynamics. Understanding evacuation dynamics can allow for the design of more comfortable and safe pedestrian facilities. However, these models do not take into account the type and state of mind of pedestrians. They deal with pedestrians as particles and the state of mind as a social force, which is represented by conservative and long-range interactions between individuals. In this study, I used the lattice model proposed in my previous study to explore the evacuation behavior of pedestrians with morality. In this model, three types of pedestrians are considered: adults, children, and injured people. Collisions between adults and children result in injured people. When the number of injured people continuously in contact with each other reaches a given value k, the injured people are removed from the lattice space. This situation is the same as that in which pedestrians start stepping over injured people. This behavior was interpreted as the morality of pedestrians. Simulations showed that the evacuation showed down and eventually became jammed owing to the injured people acting as "obstacles" in relation to the morality k.

• KIEAE Journal
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• v.10 no.2
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• pp.63-69
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• 2010

Diverse problems in wind environment has occurred through rapid urbanization and growth of high-rise building numbers, This study aims to propose the CFD (Computational Fluid Dynamics) simulation method and evaluation standard of wind environment in site planning of high rise apartment housing. The CFD simulation method proposed in this study is not existing detail simulation, but it is the method that a designer can correct and develop the design through immediate evaluation of design options in concept design phase. Therefore, the proposed CFD simulation method of wind environment in this study uses the BIM based CFD tool in which the 3D model in concept design phase can be used as for the CFD simulation. In this paper, the study examines existing evaluation standards of comfortableness level in wind environment for pedestrian near buildings, and selects new evaluation method which is possible to apply to the proposed CFD simulation method. In addition, it is to examine calculation time-spending and appropriate mesh division method for finding CFD result which is useful to find the best design options in aspect of wind environment in concept design phase. Furthermore, it proposes the wind environment evaluation method through BIM based CFD simulation.