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951.
C. Oh Y. S. Kang Y. Youn A. Konosu 《International Journal of Automotive Technology》2008,9(2):191-196
Pedestrian-related accidents are considered to be the most serious of traffic accidents due to the associated high fatality
rates. In Korea, pedestrian fatalities accounted for approximately 40% of all traffic-related fatalities in 2004. Significant
efforts have been made to develop effective countermeasures for pedestrian-vehicle collisions. A basis for devising such countermeasures
is to understand the characteristics of pedestrian-vehicle collisions. This study develops a pedestrian fatality model capable
of predicting the probability of fatality in pedestrian-vehicle collisions. Binary logistic regression and a probabilistic
neural network (PNN) are employed to estimate the probability of pedestrian fatality. Pedestrian age, vehicle type and collision
speed are used as independent variables of the fatality model. The models developed herein are valuable tools that can be
used to direct safety policies and technologies associated with pedestrian safety. 相似文献
952.
Providing accurate information about bus arrival time to passengers can make the public transport system more attractive. Such information helps the passengers by reducing the uncertainty on waiting time and the associated frustrations. However, accurate estimation of bus travel time is still a challenging problem, especially under heterogeneous and lane-less traffic conditions. The accuracy of such information provided to passengers depends mainly on the estimation method used, which in turns depends on the input data used. Hence, developing suitable estimation methods and identifying the most significant/appropriate input data are important. The present study focused on these aspects of development of estimation methods that can accurately estimate travel time by using significant inputs. In order to identify significant inputs, a data mining technique, namely the k-NN classifying algorithm, was used. It is based on the similarity in pattern between the input and historic data. These identified inputs were then used in a hybrid model that combined exponential smoothing technique with recursive estimation scheme based on the Kalman Filtering (KF) technique. The optimal values of the smoothing parameter were dynamically estimated and were updated using the latest measurements available from the field. The performance of the proposed algorithm showed a clear improvement in estimation accuracy when compared with existing methods. 相似文献
953.
Emil Aggestam Jens C. O. Nielsen Rikard Bolmsvik 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(11):1633-1657
The vertical dynamic interaction between a railway vehicle and a slab track is simulated in the time domain using an extended state-space vector approach in combination with a complex-valued modal superposition technique for the linear, time-invariant and two-dimensional track model. Wheel–rail contact forces, bending moments in the concrete panel and load distributions on the supporting foundation are evaluated. Two generic slab track models including one or two layers of concrete slabs are presented. The upper layer containing the discrete slab panels is described by decoupled beams of finite length, while the lower layer is a continuous beam. Both the rail and concrete layers are modelled using Rayleigh–Timoshenko beam theory. Rail receptances for the two slab track models are compared with the receptance of a traditional ballasted track. The described procedure is demonstrated by two application examples involving: (i) the periodic response due to the rail seat passing frequency as influenced by the vehicle speed and a foundation stiffness gradient and (ii) the transient response due to a local rail irregularity (dipped welded joint). 相似文献
954.
The early warning of incidents on urban arterial roads in a congested city can reduce delay, accidents and pollutant emission. Freeway incident detection systems implemented in recent years may not be suitable for arterial incidents. Arterial incident detection is more difficult. The traffic flow on an arterial road is not conserved from the upstream end of a road link to the downstream end because urban traffic does turn in and out of side‐streets, car‐parks and local residences. Roadside friction such as kerbside parking and shopping traffic also tends to create apparent incidents which are in fact frequent and normal events. This paper develops a definition for an arterial incident and describes a case study on an arterial road in Melbourne, Australia. The study shows that detectors upstream of an incident are more useful for incident detection than downstream detectors. It also identifies occupancy and speed as the appropriate parameters to characterise and detect arterial incidents. 相似文献
955.
956.
K. -S. Choi S. -H. Jang G. S. Shin H. -M. Kim H. C. Yoon M. E. Forrest P. A. Erickson 《International Journal of Automotive Technology》2010,11(3):429-434
The commercial fuel cell products currently appearing on the market are self-contained fuel cell engines. These engines can
be used for many applications that are presently dominated by internal combustion engines or batteries. Vehicle mounted fuel
cell auxiliary power units have been attracting attention lately. Additionally, there is a market based incentive to use multiple
small fuel cell arrays in place of a single large fuel cell for some applications. Typically, fuel cells are designed to operate
as stand-alone units. This paper investigates the ability of small commercial stacks to operate in common array arrangements.
Although an individual Nexa is able to produce 1500 W, Dual Nexas do not maintain that capability while in array configurations.
With an overall load share ratio of 1.02:1 the series array reliably produced 2900 W of power, while with an overall load
share ratio of 1.09:1 the parallel array reliably produced only 2800 W of power. This study shows that array orientation affects
both system stack net efficiency and individual stack net efficiency. The information gained from this study may be helpful
for fuel cell design and integration. 相似文献
957.
A bus rollover is one of the worst vehicle accidents that can occur. Because of the large numbers of passengers, the casualties
in a bus rollover are often high and severe. The compliance with rollover safety standards for buses and coaches is mandated
by law. This paper presents a comparative analysis of the physical meanings of regulation number 66 of the Economic Commission
for Europe (ECE R66) and standard number 220 of the American Federal Motor Vehicle Safety Standards (FMVSS 220). This comparison
was carried out using a LS-DYNA finite-element analysis. After performing a comparative analysis following ECE R66 and FMVSS
220 assessments, the investigation further demonstrated the distortion configuration of the vehicle superstructure through
the absorbed energy and its distribution over the vehicle and in sections of vehicle superstructure as well as the violation
of the passenger compartment under the rollover testing conditions of both ECE R66 and FMVSS 220. Great differences were found
between ECE R66 and FMVSS 220 in distortion configuration, reflecting differences in capability and rollover testing conditions.
These findings provide a means of evaluating bus superstructure strength and provide guidelines useful in the assessment of
regulations applied to the evaluation of bus rollover strength. 相似文献
958.
S. H. Jeong C. G. Choi J. N. Oh P. J. Yoon B. S. Kim M. Kim K. H. Lee 《International Journal of Automotive Technology》2010,11(3):409-416
This paper presents a low cost design and implementation of a parallel parking assist system (PPAS) based on ultrasonic sensors.
Generally, a PPAS requires several types of sensors, such as an ultrasonic sensor, camera sensor, radar sensor and laser sensor
for parking space detection. However, our proposed PPAS only requires two ultrasonic sensors on the front and lateral sides
for parking space detection. Moreover, a steering angle sensor and wheel speed sensor installed in the vehicle are used to
obtain vehicle position information for localization in ultrasonic range data. The hardware architecture of the PPAS based
on an electronic control unit (ECU) module, sensor modules and a human machine interface (HMI) module was proposed. Moreover,
the software architecture of the PPAS is based on system initialization, scheduling, recognition and a control algorithm.
In particular, a novel sensor algorithm was proposed to minimize the vehicle corner error of the ultrasonic sensor. A prototype
of the PPAS based on the proposed architecture was constructed. The experimental results demonstrate that the implemented
prototype is robust and successfully performs parking space detection and automatic steering control. Finally, the low cost
design and implementation of the PPAS was possible due to the cheap ultrasonic sensors, simple hardware design and low computational
complexity of the proposed algorithm. 相似文献
959.
Y. -M. Kim Y. -G. Kim S. -W. Kim C. -K. Park T. -W. Park 《International Journal of Automotive Technology》2010,11(5):673-680
The performance of brakes has become important due to increased train speeds. The brake system of a train must possess a large
brake force to stop the train safely within a limited stopping distance. However, an excessive brake force deteriorates the
ride comfort and causes the train to skid. Therefore, it is necessary to control the brake force within the adhesion force
limit. This paper presents an analytical method to estimate the relationship between the brake and adhesion forces of a disc
brake system. This method has been applied to the actual disc braking control system of the Korea High-Speed Train (HSR350x),
and the adhesion force is estimated in an actual skid condition. 相似文献
960.
P. Karthikeyan D. B. Sonawane S. C. Subramanian 《International Journal of Automotive Technology》2010,11(4):507-515
A properly functioning brake system is critical for ensuring the safe operation of any vehicle on roadways. Commercial vehicles
such as trucks, tractors-trailers and buses are equipped with an air brake system that uses compressed air as the energy transmitting
medium. This paper presents a model-based control scheme for an electropneumatic brake system for use in commercial vehicles.
A mathematical model for an electropneumatic brake system was developed and corroborated with experimental data. A control
scheme was developed based on this model and was used to regulate the pressure of air inside the brake chamber according to
a desired pressure trajectory. This control scheme was implemented on an experimental test bench, and its performance was
studied for various values of the controller parameter. The control scheme was tested for various desired pressure trajectories
reflecting actual brake operation. 相似文献