排序方式: 共有19条查询结果,搜索用时 671 毫秒
11.
Michael Baldauf Knud Benedict Sandro Fischer Michael Gluch Matthias Kirchhoff Sebastian Klaes Jens-Uwe Schröder-Hinrichs Dana Meißner Ullrich Fielitz Erland Wilske 《WMU Journal of Maritime Affairs》2011,10(2):209-226
Safe ship handling in every situation and under all prevailing circumstances of ship status and the environment is a core
element contributing to the safety of the maritime transportation system. Especially in case of emergencies, there is a need
for quick, accurate and reliable information to manoeuvre a ship safely. This paper focusses on investigations into enhanced
response to maritime emergencies by means of onboard manoeuvring support. The research and discussions are done exemplarily
for person overboard (PoB) accidents. PoB is a typical situation for application of manoeuvring assistance and decision support,
e.g. in order to return quickly to the position of the accident. Based on the analysis of selected accident case studies and
existing solutions representing the technical state-of-the-art, shortcomings will be identified and discussed, and a potential
approach for advanced manoeuvring support in the context of e-Navigation-based requirements will be introduced and discussed. 相似文献
12.
Petter Nåvik Anders Rønnquist Sebastian Stichel 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(9):1265-1282
The contact force between the pantograph and the contact wire ensures energy transfer between the two. Too small of a force leads to arching and unstable energy transfer, while too large of a force leads to unnecessary wear on both parts. Thus, obtaining the correct contact force is important for both field measurements and estimates using numerical analysis. The field contact force time series is derived from measurements performed by a self-propelled diagnostic vehicle containing overhead line recording equipment. The measurements are not sampled at the actual contact surface of the interaction but by force transducers beneath the collector strips. Methods exist for obtaining more realistic measurements by adding inertia and aerodynamic effects to the measurements. The variation in predicting the pantograph–catenary interaction contact force is studied in this paper by evaluating the effect of the force sampling location and the effects of signal processing such as filtering. A numerical model validated by field measurements is used to study these effects. First, this paper shows that the numerical model can reproduce a train passage with high accuracy. Second, this study introduces three different options for contact force predictions from numerical simulations. Third, this paper demonstrates that the standard deviation and the maximum and minimum values of the contact force are sensitive to a low-pass filter. For a specific case, an 80?Hz cut-off frequency is compared to a 20?Hz cut-off frequency, as required by EN 50317:2012; the results show an 11% increase in standard deviation, a 36% increase in the maximum value and a 19% decrease in the minimum value. 相似文献
13.
Stephane Hess Amanda Stathopoulos Danny Campbell Vikki O’Neill Sebastian Caussade 《Transportation》2013,40(3):583-607
With the growing interest in the topic of attribute non-attendance, there is now widespread use of latent class (LC) structures aimed at capturing such behaviour, across a number of different fields. Specifically, these studies rely on a confirmatory LC model, using two separate values for each coefficient, one of which is fixed to zero while the other is estimated, and then use the obtained class probabilities as an indication of the degree of attribute non-attendance. In the present paper, we argue that this approach is in fact misguided, and that the results are likely to be affected by confounding with regular taste heterogeneity. We contrast the confirmatory model with an exploratory LC structure in which the values in both classes are estimated. We also put forward a combined latent class mixed logit model (LC-MMNL) which allows jointly for attribute non-attendance and for continuous taste heterogeneity. Across three separate case studies, the exploratory LC model clearly rejects the confirmatory LC approach and suggests that rates of non-attendance may be much lower than what is suggested by the standard model, or even zero. The combined LC-MMNL model similarly produces significant improvements in model fit, along with substantial reductions in the implied rate of attribute non-attendance, in some cases even eliminating the phenomena across the sample population. Our results thus call for a reappraisal of the large body of recent work that has implied high rates of attribute non-attendance for some attributes. Finally, we also highlight a number of general issues with attribute non-attendance, in particular relating to the computation of willingness to pay measures. 相似文献
14.
Astroza Sebastian Garikapati Venu M. Pendyala Ram M. Bhat Chandra R. Mokhtarian Patricia L. 《Transportation》2019,46(5):1755-1784
Transportation - Travel model systems often adopt a single decision structure that links several activity-travel choices together. The single decision structure is then used to predict... 相似文献
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Saeed Hossein-Nia Matin Sh. Sichani Sebastian Stichel Carlos Casanueva 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(7):1051-1071
In this article, a wheel life prediction model considering wear and rolling contact fatigue (RCF) is developed and applied to a heavy-haul locomotive. For wear calculations, a methodology based on Archard's wear calculation theory is used. The simulated wear depth is compared with profile measurements within 100,000?km. For RCF, a shakedown-based theory is applied locally, using the FaStrip algorithm to estimate the tangential stresses instead of FASTSIM. The differences between the two algorithms on damage prediction models are studied. The running distance between the two reprofiling due to RCF is estimated based on a Wöhler-like relationship developed from laboratory test results from the literature and the Palmgren-Miner rule. The simulated crack locations and their angles are compared with a five-year field study. Calculations to study the effects of electro-dynamic braking, track gauge, harder wheel material and the increase of axle load on the wheel life are also carried out. 相似文献
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Leandro L. Di Stasi Rebekka RennerAndrés Catena José J. Cañas Boris M. Velichkovsky Sebastian Pannasch 《Transportation Research Part C: Emerging Technologies》2012,21(1):122-133
Developing a valid measurement of mental fatigue remains a big challenge and would be beneficial for various application areas, such as the improvement of road traffic safety. In the present study we examined influences of mental fatigue on the dynamics of saccadic eye movements. Based on previous findings, we propose that among amplitude and duration of saccades, the peak velocity of saccadic eye movements is particularly sensitive to changes in mental fatigue. Ten participants completed a fixation task before and after 2 h of driving in a virtual simulation environment as well as after a rest break of fifteen minutes. Driving and rest break were assumed to directly influence the level of mental fatigue and were evaluated using subjective ratings and eye movement indices. According to the subjective ratings, mental fatigue was highest after driving but decreased after the rest break. The peak velocity of saccadic eye movements decreased after driving while the duration of saccades increased, but no effects of the rest break were observed in the saccade parameters. We conclude that saccadic eye movement parameters—particularly the peak velocity—are sensitive indicators for mental fatigue. According to these findings, the peak velocity analysis represents a valid on-line measure for the detection of mental fatigue, providing the basis for the development of new vigilance screening tools to prevent accidents in several application domains. 相似文献
19.
Using hedonic price functions, we study the influence of access to public railway stations on the prices of surrounding condominiums in Hamburg, Germany. The study examines the influence of rail infrastructure on residential property prices, not only of individual lines, but for the entire rail network of a metropolitan region. We test the stability of the coefficients for different sets of control variables. The study also estimates public-transit-induced increases in tax revenues due to real estate price increases for a study area outside the United States. We control for spatial dependence and numerous variables correlated with the proximity of railway stations and show that access to the public transit system of the city of Hamburg is to be rated with price increases of up to 4.6%. Such premiums for higher-income neighbourhoods and for subterranean stations tend to be higher. The premiums calculated are significantly lower than average price premiums reported in previous studies, which were mostly based on much fewer variables that rail access might be correlated to. 相似文献