• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.91-100
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• 2008

Pedestrians are exposed to accidents as a result of the lack of understanding the meaning of a flashing green signal. This study was to designed to relate changes of pedestrians' crossing characteristics as a functions of flashing green signal timings. A field survey was conducted to collect pedestrian preference and safety and it was examined by signal operation experiment. Two versions of new pedestrian signal timings were compared to the existing pedestrian signal timings. The results indicated that the number of pedestrians who starts to cross during flashing green signals was significantly decreased when flashing green signals started at 1/2 or 2/3 point of crossing. However, the number of pedestrians who remain in the crossing during red signals was significantly increased when flashing green signals started at 2/3 point of crossing. This study concludes that starting flashing green signals at 1/2 point of crossing is the safest. Also, implication and directions for its practical relevance were discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.51-54
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• 2021

본 논문은 차량과 보행자 간 충돌 사고를 예측하는 V2P(Vehicle to Pedestrian) 서비스에서 보행자 휴대기기의 데이터 전송 시점을 동적으로 계산함으로써 불필요한 통신을 감소시켜 에너지 효율을 향상시키는 것을 목적으로 하며, MEC(Mobile Edge Computing) 기반 V2P 서비스를 제안하였다. V2P 서비스에서는 보행자와 차량 간 충돌 가능성을 예측하기 위하여 두 객체의 실시간 GPS 데이터가 요구된다. 이때 보편적으로 보행자에 비해 차량의 이동속도가 더 빠르기 때문에 보행자가 빠르게 이동해 들어오는 주변 차량에 발견될 수 있기 위해서는 자신의 위치에는 의미 있는 변화가 발생하지 않았더라도 차량 이동속도에 맞춘 빠른 주기로 차량 혹은 중앙 클라우드 서버로 자신의 데이터를 송신해야만 한다. 이 과정에서 보행자 휴대폰의 에너지가 급속하게 소모된다. 따라서 본 연구는 이러한 문제를 해결하기 위하여 MEC 서버를 배치한 V2P 서비스를 제안하였고, 보행자가 본인의 상태 정보를 활용하여 효율적인 다음 데이터 전송 시점을 계산할 수 있는 동적시점계산 알고리즘을 제안하였다.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.159-166
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• 2009

The purpose of this study was to develop and automatic gait event detection algorithm using single accelerometer which is attached at the top of the shoe. The sinal vector magnitude and anterior-posterior(x-axis) directional component of accelerometer were used to detect heel strike(HS) and toe off(TO), respectively. To evaluate proposed algorithm, gait event timing was compared with that by force plate and kinematic data. In experiment, 7 subjects performed 10 trials level walking with 3 different walking conditions such as fast, preferred & slow walking. An accelerometer, force plate and 3D motion capture system were used during experiment. Gait event by force plate was used as reference timing. Results showed that gait event by accelerometer is similar to that by force plate. The distribution of differences were spread about $22.33{\pm}17.45m$ for HS and $26.82{\pm}14.78m$ for To and most error was existed consistently prior to 20ms. The difference between gait event by kinematic data and developed algorithm was small. Thus it can be concluded that developed algorithm can be used during outdoor walking experiment. Further study is necessary to extract gait spatial variables by removing gravity factor.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.67-74
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• 2011

In recent years, with increasing utilization of mobile devices such as smartphones, the need for PNS(Pedestrian Navigation Systems) that provide guidance for moving pedestrians is increasing. For the navigation services, road network is the most important component when it comes to creating route and guidance information. In particular, pedestrian network requires modeling methods for more detailed and vast space compared to road network. Therefore, more efficient method is needed to establish pedestrian network that was constructed by existing field survey and manual editing process. This research proposed a pedestrian network creation method appropriate for pedestrians, based on CNS(Car Navigation Systems) data that already has been broadly constructed. Pedestrian network was classified into pedestrian link(sidewalk, side street, walking facility) and openspace link depending on characteristics of walking space, and constructed by applying different methodologies in order to create path that similar to the movements of actual pedestrians. The proposed algorithm is expected to become an alternative for reducing the time and cost of pedestrian network creation.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.435-443
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• 2013

While rural highways carry on lower traffic volumes, the deviations of running speeds between vehicles appear to be higher on rural highways than urban highways. The speed characteristic of rural highways is adding to pedestrian-related accidents which occur on a crosswalk with poor sight distance due to the limits of car headlights and lighting. Specially, the aged was mostly occupied in nighttime-related accidents on crosswalks, and pedestrians crossing on the far side of approaching vehicles appear to have the probability of fatality higher than the near side. An alternative is needed to resolve the compounded accidents, and then this study is to establish a new approach to an optimum lighting environment on a crosswalk to improve pedestrian safety. This study was conducted by a survey and a field study on the lighting of existing crosswalks. The field study shows that the existing lighting has the problem of wasting energy and impeding walking due to glare. The survey shows that nighttime sight distance on a crosswalk is required to improve and that road users prefer to be brighter pedestrian waiting space together with the crosswalk. Thus, a lighting environment that is not too bright and illuminates the crosswalk and the pedestrian waiting space is needed to implement.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.59-66
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• 2018

The utilized coefficient of friction (UCOF) as a ratio of the shear force to the normal force on the ground during walking is used to identify the point at which slip is likely to occur. Shoe walking will change the utilized coefficient of friction by shoe design such as sole thickness and hardness, heel shape, and outsole pattern. In this study, subjects are 21 adults (10 female, 11 male, age: $25.2{\pm}2.3yrs$, height: $165.6{\pm}7.2cm$), analysis variables were walking speed, GRF, when the UCOF is maximal, and Tangent of CoP-CoM angle, and correlation analysis with the utilized friction coefficient (UCOF). As a result, First, for the shod walking the time point which UCOF is maximum about heel strike was faster and the magnitude was larger than for barefoot walking. Second, the correlation between the tangent of CoP-CoM and UCOF of right foot was higher at the left heel striking point (UCOF2_h) which occurred in the post propulsion phase than at the right heel striking point (UCOF1_h). This suggests that the right foot UCOF is related to the braking phase of left foot( which is the propulsion phase of right foot) rather than the braking phase of right foot.

• Journal of Broadcast Engineering
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• v.14 no.4
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• pp.409-418
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• 2009

This paper proposes a method to estimate the flow speed of pedestrians in surveillance videos. In the proposed method, the average moving speed of pedestrians is measured by estimating the size of real-world motion from the observed motion vectors. For this purpose, a pixel-to-meter conversion factor is introduced which is calculated from camera parameters. Also, the height information, which is missing because of camera projection, is predicted statistically from simulation experiments. Compared to the previous works for flow speed estimation, our method can be applied to various camera views because it separates scene parameters explicitly. Experiments are performed on both simulation image sequences and real video. In the experiments on simulation videos, the proposed method estimated the flow speed with average error of about 0.08m/s. The proposed method also showed promising results for the real video.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1244-1253
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• 2021

In this paper, we propose a method for predicting in advance whether pedestrians will enter the hazardous area after the current time using the pedestrian trajectory prediction method and an efficient simplification method of the trajectory prediction network. In addition, we propose a method to apply KD(Knowledge Distillation) to a small network for real-time operation in an embedded environment. Using the correlation between predicted future paths and hazard zones, we determined whether to enter or not, and applied efficient KD when learning small networks to minimize performance degradation. Experimentally, it was confirmed that the model applied with the simplification method proposed improved the speed by 37.49% compared to the existing model, but led to a slight decrease in accuracy. As a result of learning a small network with an initial accuracy of 91.43% using KD, It was confirmed that it has improved accuracy of 94.76%.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.4
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• pp.1-17
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• 2022

As pedestrian deaths account for a high proportion of traffic accident deaths in Korea, interest in pedestrian safety is growing. In particular, it is necessary to develop various pedestrian-centered traffic signal operation techniques to improve the pedestrian environment at signal intersections. Therefore, in this study, a method for time-of-day operating a pedestrian signal based on residual pedestrians was studied. To this end, the pedestrian signal operation technique in response to the pedestrian demand, which is operated by extending the pedestrian signal time only during the time when the pedestrian demand and the number of remaining pedestrians increase, was applied to the field. The difference in safety according to the application of the new pedestrian signal operation technique was statistically analyzed. As a result of the analysis, the residual pedestrian rate decreased by 20% (3.3 people) before application and 8% (1.4 people) after application, and the residual pedestrian rate in the crosswalk at the time of red signal decreased by 12% (1.9 people), And it was analyzed that the position of the residual pedestrian decreased by 3.3m from 5.2m before application to 1.9m after application.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.207-207
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• 2004

고속철도의 개통이 가까워지면서 사회적 관심이 고조되고 있으며, 특히 안전과 환경의 문제가 주요한 관심사로 대두되고 있다. 특히 공기역학적 관점에서 볼 때 300km/h의 고속에서는 지금까지 국내에서 경험하지 못한 여러 가지 문제점들이 나타나리라 예상되고 있으며, 그 중에서도 승강장에 대기증인 승객 또는 보행자가 열차 통과 시에 느끼는 불쾌감과 위험에 대한 조사와 대책이 필요한 시점이다.(중략)