• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.4
• /
• pp.220-225
• /
• 2000

This paper develops a finite element model for studying occupant behavior of a mid-size truck equipped with a driver side airbag. The developed model simulates an occupant behavior using PAM-CRASH/PAM-SAFE in super computer SP2. The model is developed based on a sled test. A 50% hybrid dummy III is used for measuring head and chest accelerations and femur loads, and major injury coefficients such as HIC, CA and femur load. Inferior components such as foot rest, seat, kneebolster, crash pad, etc. are roughly modeled and defined by a rigid material model. And contact type II is used for detecting a contact with dummy. Contact type II definition uses force-deflection relationship of each body Such components as steering column which directly affect on the occupant injuy are modeled in detail and defined by an elastic-plastic material model. Airbag cushion is modeled using rivet elements. Airbag cover groove is modeled using rivet elements. Airbag tether is modeled as nonlinear bar elements. Airbag model has two vent holes to ventilating the exploded gas. Airbag is folded close to the real airbag folding procedure, and folded cautiously in order not to have initial penetration. A vehicle pulse acquired from 31mph frontal barrier test is used as input signal for the simulation. The simulation conditions are tuned to the sled test ones. The measured dummy accelerations and major injury coefficients, and filmed dummy behavior and airbag inflation process using high speed camera are compared to the simulation results to verify the developed finite element model.

• International Journal of Highway Engineering
• /
• v.19 no.6
• /
• pp.201-212
• /
• 2017

PURPOSES : The objective of this study is to identify the characteristics affecting traffic accidents that have occurred in 564 industrial complexes nationwide from 2011 to 2015. METHODS : The traffic accidents were specified using various factors such as industrial complex type (national VS. general), industrial complex degradation (old VS. non-old), location of complex (capital VS. non-capital), and traffic law violation (speeding, signal violation, and median invasion). The average number of crashes and accident ratio (fatal, severe, and both) in terms of characteristics of industrial complexes were calculated. With a sample of crashes of the industrial complexes for 5 years, statistical significances were tested to analyze and compare the differences based on industrial complex and traffic law characteristics using parametric and non-parametric methods. RESULTS : From statistical results, it is observed that the crash frequency occurring in old industrial complexes is three times higher than that in non-old industrial complexes. Old industrial complexes located in a capital area, old national industrial complexes, and old general industrial complexes are considerably related to higher crash frequency, but the fatal accident ratio appeared to have no statistical difference across industrial complex characteristics. Severe crashes are more likely to occur in non-old industrial complexes on an average. CONCLUSIONS : It is necessary to eliminate potential threats to roads and traffic in the same manner as illegal parking in industrial complexes through the restoration of old industrial complexes. To improve the efficiency of road infrastructure, efforts should be made to improve traffic safety in accordance with industrial characteristics such as planning and operation of relevant local government programs.

• International Journal of Highway Engineering
• /
• v.10 no.4
• /
• pp.199-211
• /
• 2008

This study deals with the side right-angle collisions of 4-legged signalized intersections in Cheongju. The goals are to analyze the characteristics of accidents and to find out the accident factors that affect severity using ordered probit model. In pursuing the above, the study uses the data of 580 side right-angle collisions occurred at the 181 intersections(2004-2005). The analyses show that more accidents were occurred in the nighttime and in going straight. The main cause was analyzed to be the red-light violation. Also, the main results of modeling are the following, First, the likelihood ratio index is 0.094 and t-ratio values that explain goodness of fit are significant. Second, minor road traffic volumes, minor road lanes, major road left-turn lanes, major road left-turn signal, major road yellow signal time, cross angle, major and minor road speed limits are significant factors affecting crash severities at signalized intersections.

• Journal of the Korean Society for Railway
• /
• v.15 no.2
• /
• pp.122-128
• /
• 2012

Considering structure of depot, it is impossible to install the track circuit systems due to iron-beam. Because rails and earth are connected by the iron-beam, there is much leakage current. So, it is hard to apply the track circuit systems. Thus, when trains go to the depot, sign which indicates existence of trains is used manually. In case of wrong sign, accidents occur such as train crash, derailment etc. Currently, location of trains has been found by using optical sensor in the depot to prevent the accidents. However, it costs a great deal to install and maintain the optical sensor. Therefore, this method is hardly used in train operation institutes. In this paper, virtual track circuit systems are introduced by using software program in the depot. Also, algorithm of the virtual track circuit systems is proposed. In case that signal is handled to the depot which is occupied by the train, safety is ensured by indicating sign which means existence of trains and stop signal. Also, proper fault tolerance techniques are proposed to the software by analyzing reliability and availability.

• Journal of Auto-vehicle Safety Association
• /
• v.13 no.4
• /
• pp.53-59
• /
• 2021

According to the Korean Traffic Accident Analysis System (TAAS), more than 200,000 traffic accidents occur every year. Also, the statistics including auto insurance companies data show 1.3 million traffic accidents. In the case of TAAS, the types of traffic accidents are simply divided into four; frontal collision, side collision, rear collision, and rollover. However, more detailed information is needed to assess for advanced driver assist systems at intersections. For example, directional information is needed, such as whether the vehicle in the car accident way in a straight or a left turn, etc. This study intends to redefine the type of accident with the more clear driving direction and path by referring to the Negligence standards used in automobile insurance accidents. The standards largely divide five categories of car-to-car/motorcycle /pedestrian/cyclist, and highway, and the each category is classified into dozens of types by status of the traffic signal, conflict situations. In order to present more various accident types for auto insurance accidents, the standards are reclassified driving direction and path of vehicles from crash situations. In results, the car-to-car accidents are classified into 33 accident types, car-to-pedestrian accidents have 19 accident types, car-to-motorcycle accidents have 38 accident types, and car-to-cyclist accidents are derived into 26 types.

• Journal of Auto-vehicle Safety Association
• /
• v.8 no.1
• /
• pp.31-37
• /
• 2016

The Child Occupant Safety Assessment was first introduced and carried out by Euro NCAP in 2003, with the goal of ensuring manufacturers to develop safe vehicles for passengers of all ages; the objective was to evaluate the safety and protection offered by different Child Restraint Systems (CRS) in the event of a crash. In 2013, the formerly used P child dummy series was replaced by newer and more biofidelic Q1.5 and Q3 child dummies, representing 1.5 and 3 year old children respectively. The frontal and side impact dynamic performances of the Q1.5 and Q3 were tested within all classes of vehicles assessed by Euro NCAP at the time. As an extension to that initiative, Q6 and Q10 child dummies were later developed representing children of 6 and 10 years old. Since the protection of larger children during vehicle crashes relies greatly on the interaction of vehicle restraint systems such as seat belt and the CRS, instrumented Q6 and Q10 dummies will be used to assess the protection offered in the event of front and side impact crashes. In this paper, we focused on injury criteria of Q6 and Q10 child dummies at 64 kph 40% offset frontal crash test. The whole procedure was designed with DFSS analysis. The full vehicle sled test results of both dummies were conducted with different restraint systems settled through previous sled test. It showed that several injury criteria and image data were collected as the result of the full vehicle sled test. Based on the results of these investigations, this paper describes which factor is most important and combination shows the best performance when evaluating rear seat occupant protection for Q6 and Q10 child dummies.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.1
• /
• pp.26-37
• /
• 2017

The study is to develop safety performance functions(SPFs) for urban intersections using random effects Tobit regression model and to analyze correlations between crashes and factors. Also fixed effects Tobit regression model was estimated to compare and analyze model validation with random effects model. As a result, AADT, speed limits, number of lanes, land usage, exclusive right turn lanes and front traffic signal were found to be significant. For comparing statistical significance between random and fixed effects model, random effects Tobit regression model of total crash rate could be better statistical significance with $R^2_p$ : 0.418, log-likelihood at convergence: -3210.103, ${\rho}^2$: 0.056, MAD: 19.533, MAPE: 75.725, RMSE: 26.886 comparing with $R^2_p$ : 0.298, log-likelihood at convergence: -3276.138, ${\rho}^2$: 0.037, MAD: 20.725, MAPE: 82.473, RMSE: 27.267 for the fixed model. Also random effects Tobit regression model of injury crash rate has similar results of model statistical significant with random effects Tobit regression model.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.8 s.227
• /
• pp.976-983
• /
• 2004

In high-density hard disk drives, the slider should be made to fly close to the magnetic recording disk to generate better signal resolution and at an increasingly high velocity to achieve better data rate. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation. Contamination particles in the hard disk drive can cause serious problems including slider crash and thermal asperities. We investigated the number and the sizes of particles generated in the hard disk drive, operating at increasing disk rotational speeds, in the CSS mode. CNC (condensation nucleus counter) and PSS (particle size selector) were used for this investigation. In addition, we examined the particle components by using SEM (scanning electron microscopes), AES (auger electron spectroscopy), and TOF-SIMS (time of flight-secondary ions mass spectrometry). The increasing disk rotational speed directly affected the particle generation by slider disk interaction. The number of particles that were generated increased with the disk rotational speed. The particle generation rate increased rapidly at motor speeds above 8000 rpm. This increase may be due to the increased slider disk interaction. Particle sizes ranged from 14 to 200 nm. The particles generated by slider disk interaction came from the lubricant on the disk, coating layer of the disk, and also slider surface.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.5
• /
• pp.126-135
• /
• 2014

This paper describes the development and verification of control algorithms for V2X and environmental sensor integrated intersection support and safety systems. The objective of the research is to develop core technologies for effective fusion of V2X and environmental sensors and to develop new safety function for intersection safety. One of core technologies is to achieve the improvement of GPS accuracy, and the other is to develop the algorithm of a vehicle identification which matches all data from V2X, vehicle sensors and environmental sensors to specific vehicles. A intersection optimal pass (IOP) algorithm is designed based on these core technologies. IOP recommends appropriate speed to pass the intersection in the consideration of traffic light signal and preceeding vehicle existence. Another function is developed to prevent a collision avoidance when car crash caused by traffic violation of surrounding vehicles is expected. Finally all functions are implemented and tested in three test vehicles. It is shown that IOP can support convenient and comfortable driving with recommending optimal pass speed and collision avoidance algorithm can effectively prevent collision caused by traffic sign violation of surrounding vehicles.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.6
• /
• pp.469-474
• /
• 2018

As urban population increases, research on urban environmental noise is getting more attention. In this study, we classify the abnormal noise occurring in traffic situation by using a deep learning algorithm which shows high performance in recent environmental noise classification studies. Specifically, we classify the four classes of tire skidding sounds, car crash sounds, car horn sounds, and normal sounds using convolutional neural networks. In addition, we add three environmental noises, including rain, wind and crowd noises, to our training data so that the classification model is more robust in real traffic situation with environmental noises. Experimental results show that the proposed traffic sound classification model achieves better performance than the existing algorithms, particularly under harsh conditions with environmental noises.