Mathematical and Computer Modelling of Dynamical Systems
Mathematical models have been used widely to investigate the vehicle-passenger-infrastructure dyn... more Mathematical models have been used widely to investigate the vehicle-passenger-infrastructure dynamical interaction; however, the responses of various heavy-duty city bus models to estimate ride co...
Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute o... more Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute of Transportation Systems“. We are publishing in this series fascinating, scientific topics from the Institute of Transportation Systems of the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt e.V. - DLR) and from his environment. We are providing libraries with a part of the circulation. Outstanding scientific contributions and dissertations are here published as well as projects reports and proceedings of conferences in our house with different contributors from science, economy and politics. With this series we are pursuing the objective to enable a broad access to scientific works and results. We are using the series as well as to promote practically young researchers by the publication of the dissertation of our staff and external doctoral candidates, too. Publications are important milestones on the academic career path. With the series „Reports of the DLR-Institut...
The development of advanced technologies has led to the emergence of autonomous vehicles. Herein,... more The development of advanced technologies has led to the emergence of autonomous vehicles. Herein, autonomous public transport (APT) systems equipped with prioritization measures are being designed to operate at ever faster speeds compared to conventional buses. Innovative APT systems are configured to accommodate prevailing passenger demand for peak as well as non-peak periods, by electronic coupling and decoupling of platooned units along travel corridors, such as the dynamic autonomous road transit (DART) system being researched in Singapore. However, there is always the trade-off between high vehicle speed versus passenger ride comfort, especially lateral ride comfort. This study analyses a new APT system within the urban context and evaluates its performance using microscopic traffic simulation. The platooning protocol of autonomous vehicles was first developed for simulating the coupling/decoupling process. Platooning performance was then simulated on VISSIM platform for variou...
Abstract Due to the effect of curing temperature and heat absorption on the performance of cement... more Abstract Due to the effect of curing temperature and heat absorption on the performance of cement-treated bases (CTB), thermal shrinkage cracks can happen in CTB during the early-age curing period. However, there have been non-existent studies on the relationship between temperature distribution in CTB versus various curing methods. In this paper, a field experiment was conducted to monitor temperature at different depths and to investigate fundamental mechanical properties of CTB. An Artificial Neural Network (ANN) model was also developed to estimate temperature distribution in CTB segments exposed to three different curing methods (wet burlap, wet geotextile, and asphalt emulsion). The results indicated that wet burlap and wet geotextile curing methods exhibited better quality cures than asphalt emulsion, expressed by higher 14-day compressive and splitting tensile strengths, due to less temperature absorbed into CTB structure. Shrinkage cracks were also observed on CTB surface cured with asphalt emulsion due to more heat absorption. The ANN-based model proposed using four input parameters: air temperature, measurement depths, curing methods, and times of day showed a high accuracy with R-value ≥0.96 and average MSE ≈ 0.0038. A sensitivity analysis using Connection Weight Approach has proven the importance of curing methods which contributed to the highest dominance of 30.1%, whereas air temperature, times of day, and measurement depths accounted for 26.4%, 26.6%, and 16.9%, respectively. Thus, the ANN-based model has accurately estimated temperature distribution in CTB while curing.
Improving ride comfort for bus passengers experiencing vibrations under the excitation of road ro... more Improving ride comfort for bus passengers experiencing vibrations under the excitation of road roughness is a meaningful solution to attract more public transport ridership. While many research studies have been conducted to simulate car and truck dynamics, few studies have studied bus dynamics. This study developed multi-degrees-of-freedom (3-DOF quarter, 5-DOF half and 9-DOF full) mathematical bus models in Matlab/Simulink and compared these models in calculating passenger ride comfort on buses operating along urban bus lanes. The comparison results have shown that the 9-DOF full bus model is the best alternative to measure passenger ride comfort within the error of 2%, as compared to 5-DOF half and 3-DOF quarter bus model with 7% and 20% error, respectively. However, the modelling complexity is much higher in cases of half and full bus models. The widely used quarter vehicle model for designing vehicle suspension and for evaluating road roughness are reasonable and pragmatic to m...
Relationship between estimation of O/D flows with traffic counts and traffic assignment [Cascetta... more Relationship between estimation of O/D flows with traffic counts and traffic assignment [Cascetta, 2001] Traffic demand representation by traffic count [Bert, 2009] Four cases for OD estimation
Mathematical and Computer Modelling of Dynamical Systems
Mathematical models have been used widely to investigate the vehicle-passenger-infrastructure dyn... more Mathematical models have been used widely to investigate the vehicle-passenger-infrastructure dynamical interaction; however, the responses of various heavy-duty city bus models to estimate ride co...
Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute o... more Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute of Transportation Systems“. We are publishing in this series fascinating, scientific topics from the Institute of Transportation Systems of the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt e.V. - DLR) and from his environment. We are providing libraries with a part of the circulation. Outstanding scientific contributions and dissertations are here published as well as projects reports and proceedings of conferences in our house with different contributors from science, economy and politics. With this series we are pursuing the objective to enable a broad access to scientific works and results. We are using the series as well as to promote practically young researchers by the publication of the dissertation of our staff and external doctoral candidates, too. Publications are important milestones on the academic career path. With the series „Reports of the DLR-Institut...
The development of advanced technologies has led to the emergence of autonomous vehicles. Herein,... more The development of advanced technologies has led to the emergence of autonomous vehicles. Herein, autonomous public transport (APT) systems equipped with prioritization measures are being designed to operate at ever faster speeds compared to conventional buses. Innovative APT systems are configured to accommodate prevailing passenger demand for peak as well as non-peak periods, by electronic coupling and decoupling of platooned units along travel corridors, such as the dynamic autonomous road transit (DART) system being researched in Singapore. However, there is always the trade-off between high vehicle speed versus passenger ride comfort, especially lateral ride comfort. This study analyses a new APT system within the urban context and evaluates its performance using microscopic traffic simulation. The platooning protocol of autonomous vehicles was first developed for simulating the coupling/decoupling process. Platooning performance was then simulated on VISSIM platform for variou...
Abstract Due to the effect of curing temperature and heat absorption on the performance of cement... more Abstract Due to the effect of curing temperature and heat absorption on the performance of cement-treated bases (CTB), thermal shrinkage cracks can happen in CTB during the early-age curing period. However, there have been non-existent studies on the relationship between temperature distribution in CTB versus various curing methods. In this paper, a field experiment was conducted to monitor temperature at different depths and to investigate fundamental mechanical properties of CTB. An Artificial Neural Network (ANN) model was also developed to estimate temperature distribution in CTB segments exposed to three different curing methods (wet burlap, wet geotextile, and asphalt emulsion). The results indicated that wet burlap and wet geotextile curing methods exhibited better quality cures than asphalt emulsion, expressed by higher 14-day compressive and splitting tensile strengths, due to less temperature absorbed into CTB structure. Shrinkage cracks were also observed on CTB surface cured with asphalt emulsion due to more heat absorption. The ANN-based model proposed using four input parameters: air temperature, measurement depths, curing methods, and times of day showed a high accuracy with R-value ≥0.96 and average MSE ≈ 0.0038. A sensitivity analysis using Connection Weight Approach has proven the importance of curing methods which contributed to the highest dominance of 30.1%, whereas air temperature, times of day, and measurement depths accounted for 26.4%, 26.6%, and 16.9%, respectively. Thus, the ANN-based model has accurately estimated temperature distribution in CTB while curing.
Improving ride comfort for bus passengers experiencing vibrations under the excitation of road ro... more Improving ride comfort for bus passengers experiencing vibrations under the excitation of road roughness is a meaningful solution to attract more public transport ridership. While many research studies have been conducted to simulate car and truck dynamics, few studies have studied bus dynamics. This study developed multi-degrees-of-freedom (3-DOF quarter, 5-DOF half and 9-DOF full) mathematical bus models in Matlab/Simulink and compared these models in calculating passenger ride comfort on buses operating along urban bus lanes. The comparison results have shown that the 9-DOF full bus model is the best alternative to measure passenger ride comfort within the error of 2%, as compared to 5-DOF half and 3-DOF quarter bus model with 7% and 20% error, respectively. However, the modelling complexity is much higher in cases of half and full bus models. The widely used quarter vehicle model for designing vehicle suspension and for evaluating road roughness are reasonable and pragmatic to m...
Relationship between estimation of O/D flows with traffic counts and traffic assignment [Cascetta... more Relationship between estimation of O/D flows with traffic counts and traffic assignment [Cascetta, 2001] Traffic demand representation by traffic count [Bert, 2009] Four cases for OD estimation
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