• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.76-84
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• 2010

Many pedestrian simulation models for micro-scale spaces as building indoor areas have been proposed for the last decade and two models - social force model and floor field model - are getting attention. Among these, CA-based floor field model is viewed more favourable for computer simulations than computationally complex social force model. However, Kirchner's floor field model has limitations in capturing the differences in dynamic values of different agents and this study proposes an enhanced algorithm. This study improved the floor field model in order for an agent to be able to exclude the influences of its own dynamic values by changing the data structure, and, also modified the initial dynamic value problem in order to fit more realistic environment. In the simulations, real 3D building data stored in a spatial DBMS were used considering future integration with indoor localization sensors and real time applications.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.193-198
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• 2015

A large number of vision applications rely on matching keypoints across images. Pedestrian detection is under constant pressure to increase both its quality and speed. Such progress allows for new application. A higher speed enables its inclusion into large systems with extensive subsequent processing, and its deployment in computationally constrained scenarios. In this paper, we focus on improving the speed of pedestrian detection using HOG(histogram of oriented gradient) and multi frame operation which is robust to illumination changes in cluttering images. The result of our simulation indicates that the detection rate and speed of the proposed method is much faster than that of conventional HOG and differential images.

• Wind and Structures
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• v.9 no.2
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• pp.147-158
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• 2006

The purpose of this paper is to find a more accurate method to evaluate pedestrian wind by computational fluid dynamics approach. Previous computational fluid dynamics studies of wind environmental problems were mostly performed by simplified models, which only use simple geometric shapes, such as cubes and cylinders, to represent buildings and structures. However, to have more accurate and complete evaluation results, various shapes of blocking objects, such as trees, should also be taken into consideration. The aerodynamic effects of these various shapes of objects can decrease wind velocity and increase turbulence intensity. Previous studies simply omitted the errors generated from these various shapes of blocking objects. Adding real geometrical trees to the numerical models makes the calculating domain of CFD very complicated due to geometry generation and grid meshing problems. In this case the function of Porous Media Condition can solve the problem by adding trees into numerical models without increasing the mesh grids. The comparison results between numerical and wind tunnel model are close if the parameters of porous media condition are well adjusted.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.6
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• pp.77-87
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• 2014

It has reported that a median bus-stop island on an exclusive median bus lane (EMBL) has shortened a crossing distance unit, encouraged a pedestrian's illegal crossing, and increased the number of accidents in the area. This study presents (1) the analysis of inappropriate pedestrian crossing patterns collected on exclusive median bus corridors and (2) the estimated performance of safety barriers restraining the occurrence of those. Total 19,649 pedestrian crossing data collected at the 'Sookmyung-university' median bus-stop, and the inappropriate pedestrian crossing patterns among those were grouped in terms of time and space violations. Physical safety barriers restraining illegal pedestrian crossings were considered as an alternative, and its performance in safety was quantified through microscopic simulation with conflict analyses by using surrogate safety assessment model. The findings suggest the number of conflicts reduced be 24.9 percentages compared to the one of the present condition when the physical safety barriers are placed at each of the eight ends of the EMBL pedestrian crossing.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.131-137
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• 2004

Conventional traffic signal optimization models assume that green intervals for pedestrian crossings are given as exogenous inputs such as minimum green intervals for straight-ahead movements. As the result, in reality, the green intervals of traffic movements may not distribute adequately by the volume/saturation-flow of them. In this paper, we proposed signal optimization models formulated in BMILP to integrate pedestrian crossings into traffic movements under under-saturated traffic flow. The model simultaneously optimizes traffic and pedestrian movements to minimize weighted queues of primary queues during red interval and secondary queues during queue clearance time. A set of linear objective function and constraints set up to ensure the conditions with respect to pedestrian and traffic maneuvers. Numerical examples are given by pedestrian green intervals and the number of pedestrian crossings located at an arm. Optimization results illustrated that pedestrian green intervals using proposed models are greater than those using TRANSYT-7F, but opposite in the ratios of pedestrian green intervals to the cycle lengths. The simulation results show that proposed models are superior to TRANSYT-7F in reducing delay, where the longer the pedestrian green interval the greater the effect.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.999-1000
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• 2010

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.85-95
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• 2017

This study aims to identify the throw distance in terms of truck weight, bumper height, and speed in a truck and pedestrian collision, and to propose a model for throw distance estimates. For this purpose, a simulation analysis is performed using the PC-crash program with the following experiment conditions: Truck weight of 5t, 15t, and 25t, Bumper height from 0.3m to 0.6m by 0.1m, and speed from 10km/h to 100km/h by 10 km/h. Experimental results show that the truck speed and bumper height are found to be significant factors for pedestrian throw distance, but truck weight is not a significant factor. Also, a regression model is developed for pedestrian throw distance estimate from the multiple regression analysis. The adjusted $R^2$ value of the model is 93.3%, which is very good explanatory power.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.125-134
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• 2011

In order to reconstruct vehicle-pedestrian collision accidents, this paper presents a fuzzy tool to estimate accurately the impact velocity of the vehicle using parameters which could be easily collectable at the accident scene. The fuzzy rules and membership functions were set up using number of over 200 domestic and foreign data from accidents and empirical tests and 700 data from multibody simulation experiments. The developed fuzzy tool deduces the category of pedestrian trajectory and impact speed of the vehicle using 4 membership functions and 2 logic rules. The membership function of throw distance was differently set according to the deduced category of trajectories. The implemented fuzzy program was validated through comparing with the domestic and foreign empirical data. The output results agree very well in impact velocities of vehicle resulting the accuracy and usefulness of the developed tool in the reconstruction analysis of vehicle-pedestrian collision accidents.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.105-113
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• 2002

As the number of pedestrian accident increases, the reconstruction of an accident becomes important to find the source of the fault. Generally, accidents are reconstructed by the intuition of experts or primitive physics. A reconstruction method is proposed using sophisticated optimization technology. At first, a dynamic simulation model is established for the accident environment. Occupant analysis for automobile crashworthiness is employed. The situation before an accident is identified by optimization. The impact velocity and the position of the pedestrian are utilized as design variables. The design variables are found by minimizing the difference between the simulation and the real accident. The optimization process is performed by linking an occupant analysis program MADYMO to an optimization program VisualDOC. Since the involved analysis is dynamics and highly nonlinear, response surface method is selected for the optimization process. Problems are solved for various situations.

• Journal of the Korea Safety Management & Science
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• v.15 no.3
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• pp.93-103
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• 2013

In recently, a growing concern for the health of urban residents increased interests in a variety of outdoor activities simply be done in terms of cost and time. They are specially interested in low-impact and safe exercises around residential or working area. Walking is the one of easily doing exercise in daytime or nighttime near residential area. The sidewalks of boulevard near the residential area is the best place for exercise because of easy access and the green space with roadside trees. However, if the nighttime is not guaranteed the proper lighting condition, the possibility of exposure to crime and the threat to pedestrian safety can be increased. Because roadside trees are one of the potential obstacle for lighting condition, supplementary lightings are important to mitigate interruption for safety. To meet such a need, the purpose of this study is to propose a simulation approach which improves lighting condition on sidewalks of boulevard with variety of roadside trees. To do so, the simulation approach is applied for analyzing the interrupted condition by classified five standard types of roadside trees considering the growth of them and finding optimal layout of supplementary luminaires by lighting types. The results of this approach shows that it is useful for assessing the safety of pedestrian in nighttime.