Road transport plays a crucial role in facilitating mobility and the movement of goods,particularly in the Extended Bangkok Metropolitan Region(EBMR),Thailand.This area is undergoing rapid industrialization and urbani...Road transport plays a crucial role in facilitating mobility and the movement of goods,particularly in the Extended Bangkok Metropolitan Region(EBMR),Thailand.This area is undergoing rapid industrialization and urbanization,resulting in significant energy consumption and greenhouse gas(GHG)emissions.This study examined the relationships among individual socioeconomic factors,travel characteristics,and energy consumption characteristics and their impacts on GHG emissions from road transport.The path analysis technique was applied to identify the key driving factors and their causal relationships.The data were collected through 1600 questionnaire surveys with road drivers in representative areas of the EBMR from December 2022 to May 2023.The results revealed that individual socioeconomic factors significantly influenced GHG emissions from road transport.Among the drivers,factors such as income,age,education,and driving experience indirectly influenced travel characteristics and energy consumption characteristics,impacting GHG emissions.Similarly,individual socioeconomic factors affected the travel characteristics of tourists and personal travelers.Driving experience was a crucial factor for public road transport and freight vehicle drivers,influencing travel characteristics and contributing to GHG emissions.These findings highlight the importance of key policy recommendations,such as promoting the adoption of electric vehicles,optimizing public transport,incentivizing low-emission tourism,and modernizing freight transport with clean technologies,to enhance efficiency,reduce emissions,and support regional sustainability.This study provides policy-makers with insights into the key factors influencing GHG emissions across different driving factors,revealing how individual socioeconomic factors impact travel characteristics and energy consumption characteristics.The findings will inform the development of targeted emission reduction strategies and sustainable transport policies.展开更多
A simple model for a set of integrate-and-fire neurons based on the weighted network is introduced. By considering the neurobiological phenomenon in brain development and the difference of the synaptic strength, we co...A simple model for a set of integrate-and-fire neurons based on the weighted network is introduced. By considering the neurobiological phenomenon in brain development and the difference of the synaptic strength, we construct weighted networks develop with link additions and followed by selective edge removal. The network exhibits the small-world and scale-free properties with high network efficiency. The model displays an avalanche activity on a power-law distribution. We investigate the effect of selective edge removal and the neuron refractory period on the self-organized criticality of the system.展开更多
The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain level.Symmetrical tension-compress...The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain level.Symmetrical tension-compression cycle tests are performed on pure copper specimens to observe the inhomogeneous distribution of slip deformation and its evolution with cycle number.Cyclic hardening process and stable hysteretic behavior of pure copper under cyclic loading are simulated by applying a crystal plasticity constitutive model including nonlinear kinematic hardening associated with the polycrystalline representative volume element(RVE)constructed by Voronoi tessellation.Inhomogeneous deformation processes of materials under six different strain amplitudes are simulated by 1600 cycles,respectively.We discuss the variation law of the inhomogeneous meso-deformation distribution of material with the increase in cycle number,and research the rationality of characterizing the inhomogeneous deformation distribution and variation with the statistical standard deviation of the micro-longitudinal strain or the statistical average of the first principal strain based on the statistical analysis of the inhomogeneous deformation of the polycrystalline RVE model during the cycling process.It is found that these two parameters are related to and approximately inversely proportional to the length of measuring gauge.展开更多
The permanent deformation (rutting) of pavement is a major distress in flexible pavement. It is related to vehicles properties and/or pavement materials and conditions. This article presents an extensive experimental ...The permanent deformation (rutting) of pavement is a major distress in flexible pavement. It is related to vehicles properties and/or pavement materials and conditions. This article presents an extensive experimental investigation in order to compare between the aggregate gradation according to Superpave and Marshall methods of asphalt concrete mix design on pavement rutting and to examine the sensitivity of rutting resistance to aggregate gradation. A wheel truck machine has been used for measurement of pavement rutting (permanent deformation). The tests were carried out at two controlled different air temperature 55℃ and 25℃. The results obtained showed that the adopting of aggregate gradation procedure of Superpave method of pavement mix design for Marshall method of asphalt concrete mix design can reduce the pavement rutting by about 50%. This achievement may be related to missing of three sieves in aggregate gradation procedure of Marshall method which controls rounded and finer aggregate particles. These sieves provide more continuity for aggregate gradation to ensure filling unnecessary gaps and produce more contact points between the aggregates in Hot Mix Asphalt (HMA). The outputs of the research support modifying Marshall method of asphalt concrete mix design by adopting aggregate gradation proposed in Superpave method. The results of study also showed that the coarser aggregate provided more resistance to pavement rutting.展开更多
The Tianjin Port is the largest man-made port in China. Since the navigation channel of the Tianjin Port is constructed by dredging, a very important problem, as many people concerned, is the submarine slope stability...The Tianjin Port is the largest man-made port in China. Since the navigation channel of the Tianjin Port is constructed by dredging, a very important problem, as many people concerned, is the submarine slope stability. As the environment on land is different from that in submarine, it is necessary to evaluate the influence of the environmental loading, such as wave and tide, on the stability of navigation channel slope. In the present study, based on the observed results, the characteristics of the navigation channel slope are summarized, and the causes of creating the special slope shape are analyzed. The ioles of waves and tides are evaluated, and failure mechanics are discussed to helq us predict what will happen in the future.展开更多
In the last decade, Brazil was the scene of two of the world’s biggest disasters related to mining tailings dams. The collapse of the Mariana and Brumadinho dams was catastrophic event that brought to light major env...In the last decade, Brazil was the scene of two of the world’s biggest disasters related to mining tailings dams. The collapse of the Mariana and Brumadinho dams was catastrophic event that brought to light major environmental and humanitarian crises. Facts like this incite debate on the safety of dam construction methods and highlight the need for a broad discussion of dam safety legislation in the country. From the above, this paper promotes a review of various forms of construction of tailings dams and their associated problems, as well as discusses the techniques for soil reinforcement and their construction methods. The work also brings an overview of the Brazilian dams from April to July 2019, tracing the context of the Brazilian tailings dams months after the tragedy of Brumadinho. The methodology includes a robust literature review and discourse analysis. In Brazil, the number of ruptured dams is alarming, especially in the state of Minas Gerais, in which more than 7 have broken in the last two decades. Among the damages, the deaths impact society abruptly and were cataloged 455 deaths, of which 216 correspond to the rupture of the dam of the Córrego do Feijão mine in Brumadinho. To evaluate and diagnose a dam, one should consider ordinance N ° 70,389, 2017 revoked by Resolution ANM n ° 95, of February 7, 2022. In this context, in March 2019, we experienced several disturbing situations regarding dam instability in the state of Minas Gerais, being categorized as risky structures. To exemplify, one can cite dams classified as level 2 risk that became level 3. Due to the above facts, several studies are being conducted to improve soil aspects. For example, we highlight the increase in soil resistance that can be done using commercial and alternative materials available in the environment.展开更多
Understanding the factors contributing to CO_(2)emissions is pivotal for informed policy-making and sustainable urban development.This study probes the interconnections between urban attributes,transportation patterns...Understanding the factors contributing to CO_(2)emissions is pivotal for informed policy-making and sustainable urban development.This study probes the interconnections between urban attributes,transportation patterns,and socioeconomic factors concerning CO_(2)emissions using Decision Tree analysis across a substantial dataset of US zip codes.The dataset was carefully prepared to ensure accuracy and relevance,considering temporal,geographical,and socioeconomic heterogeneity.The Decision Tree algorithm was applied iteratively to evaluate variable interactions and identify critical thresholds that influence carbon emissions.The findings of this study shed light on the key drivers of CO_(2)emissions across US zip codes.The analysis reveals significant variations in the relative importance of different factors in different regions,emphasizing the need for localized and tailored strategies to address carbon reduction targets effectively.The research provides a more holistic understanding that can drive effective urban planning and energy policies,ultimately contributing to the global effort to reduce carbon emissions and combat climate change.The findings from this research underscore the importance of multidisciplinary approaches in addressing environmental challenges and highlight the necessity for continuous innovation in analytical methodologies to keep pace with the evolving urban landscapes.展开更多
The accessibility of a destination-based transportation system is defined to quantify the performance of transportation systems which access a distinct destination. The access cost is used to reflect the utility of th...The accessibility of a destination-based transportation system is defined to quantify the performance of transportation systems which access a distinct destination. The access cost is used to reflect the utility of the transportation system including the fatigue and inconvenience in the total cost. The cost is quan- tified by two coefficients which represent the different characteristics of various people. The average cost and the income-relative accessibility are used to describe various aspects of the accessibility and to evaluate the accessibility of a destination-based system. A case study uses data from the Kunming transportation system to evaluate the accessibility of the present city airport. The calibrated coefficients are then used to evaluate the transportation system to the new Kunming international airport. The results show that this transportation accessibility evaluation can be combined with transportation planning to study transportation sub-systems.展开更多
The paper analyzes the equity of road resources distribution in urban areas by modeling the competitive relationship among different road users. A logistic model is used to describe the development of different traffi...The paper analyzes the equity of road resources distribution in urban areas by modeling the competitive relationship among different road users. A logistic model is used to describe the development of different traffic modes in the transportation network. The system is similar to the species competition model, so a two-species model is used to analyze the relationship between users based on the stability of the equilibrium points. The Lotka-Volterra model is then used to describe the multi-species cases with numerical examples, showing that this model can describe the effects of the road space distribution on the competitive user relationships. Policy makers must ensure the equity of road resources distribution so that each urban transportation mode is properly developed for sustainable social development.展开更多
Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experiment...Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall, cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical, homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory. The boundary conditions and continuity conditions for the solution of the problem were found. The forcedeformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained. The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip, depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness, and numerical simulation is a powerful method for determining plant cell mechanical properties.展开更多
Road maintenance work brings costs to the government and delays to users. The setting up of work zones often leads to severe congestion during peak hours, especially in busy urban areas. A road maintenance delay model...Road maintenance work brings costs to the government and delays to users. The setting up of work zones often leads to severe congestion during peak hours, especially in busy urban areas. A road maintenance delay model is presented here that includes consideration of excessive traffic flow and non-motorists. Atrial-and-error method is used to find the optimal work zone length and the best work starting time to minimize the total cost of maintenance and delays. A numerical example with a sensitivity analysis is also given. The results show that optimal starting time is not sensitive to the flow speed and the increase of work zone speeds sharply reduces the total cost when the road is congested.展开更多
The helmet of riders of electric bicycles plays an important role in reducing injuries and deaths in traffic accidents.This paper conducts a questionnaire survey,data analysis and modelling to investigate the influenc...The helmet of riders of electric bicycles plays an important role in reducing injuries and deaths in traffic accidents.This paper conducts a questionnaire survey,data analysis and modelling to investigate the influencing factors of electric bicycle helmet wearing.First,living area,gender,age,marital status and education level are selected as independent variables for data analysis.The factor analysis divides the sentiments of electric bicyclists for wearing helmets into four aspects:safety perception,practical sensation,satisfaction perception and emergency perception,and ordinal multiple logistic models are built to analyse the influencing factors.The result shows that people aged 18−25,26−35,36−45 and 46−55 are 1.3,1.8,2.0 and 2.3 times more likely,respectively,to have at least a grade higher safety perception than those aged 56 and over;men are 0.77 times more likely than women to feel at least one grade higher about the practical perception and 1.48 times more than women about the satisfaction perception;people with primary school,junior high school,senior high school,junior college and bachelor’s degree education are 1.64,2.44,1.50,1.70 and 1.55 times more likely,respectively,than people with a master’s degree to feel at least one grade higher about the satisfaction perception.展开更多
Currently applied prediction methods of regional freight traffic and freight ton-kilometer forecasting were analyzed using typical Chinese regional goods transportation characteristics. The review of prediction method...Currently applied prediction methods of regional freight traffic and freight ton-kilometer forecasting were analyzed using typical Chinese regional goods transportation characteristics. The review of prediction methods showes that practical planning experts tend to apply the traditional methods which are easier to implement. The comparison also demonstrates that a combination of traditional methods is more effective than the simple models for practical planning. Research using the statistical data for the Yangtze Delta, Pearl River Delta, and Bohai Rim areas shows that ignoring differences between transport modes impacts the prediction accuracy. The four main transport modes suit different methods. The results show that the power model is better for railways, and the linear model is better for highways and waterways. Thus a combined model gives better results for all modes. The results for regional systems can be generalized to national transportation systems.展开更多
This paper reports the effects of using an ＂odd and even＂ traffic restriction policy in Beijing during the 2008 Olympic Games. Based on data from 529 traffic detectors on the expressway network and some main arteria...This paper reports the effects of using an ＂odd and even＂ traffic restriction policy in Beijing during the 2008 Olympic Games. Based on data from 529 traffic detectors on the expressway network and some main arterials in Beijing, China, a comparative analysis has been carried out on the following parameters： the total traffic volume within the expressway network, the total traffic volume on different ring expressways, the traffic volume and speed of a freeway segment, and an arterial street before and after the implementation of the traffic restriction policy. The results show that during the traffic restriction period, although more than 50% of vehicles were forbidden to travel in Beijing, the traffic volume was only reduced by 20%-40% while the travel speed had been increased by 10%-20%. This suggests that such traffic restriction policy may be an effective shortterm management measure in dealing with increased transportation demand and congestion during major events, such as the Olympic Games. Results also indicate that vehicle travel demand does not decrease with the same proportion as the total vehicles forbidden, at least for the expressway and main arterials in a city.展开更多
Drowsy driving has received comparatively less attention in traffic safety literature when compared to other safety issues,despite its devastating impact on society in terms of human life lost and associated economic ...Drowsy driving has received comparatively less attention in traffic safety literature when compared to other safety issues,despite its devastating impact on society in terms of human life lost and associated economic burdens.Therefore,this significant safety threat requires a thorough investigation.To address the temporal instability of factors contributing to crashes involving drowsy drivers,this paper divides the crash data into four time periods while capturing unobserved heterogeneity in the means and variances of random parameters.To explore the determinants affecting the severity of injuries sustained by drowsy drivers involved in single-vehicle crashes,injury outcomes are categorized into three groups:serious,moderate,and no injuries.Using four years of crash data from the state of Washington between 2013 and 2016,a wide range of factors were examined,including driver characteristics,roadway conditions,crash characteristics,vehicle conditions,lighting conditions,and temporal factors.The estimation results reveal that there is temporal instability in terms of the effect of determinants on injury severity across the years.However,some factors exhibit stable effects,such as female drivers,sober drivers,and non-hit-and-run crashes.Based on the findings of this study,decision-makers,traffic engineers,and traffic authorities can gain valuable knowledge and insights into the factors contributing to drowsy-related crashes,enabling them to make informed recommendations for safety countermeasures.展开更多
Despite the importance of heavy vehicles in Australia’s transportation system,little is known on the factors influencing injury severity from accidents involving a single heavy vehicle.Heavy vehicular crashes have be...Despite the importance of heavy vehicles in Australia’s transportation system,little is known on the factors influencing injury severity from accidents involving a single heavy vehicle.Heavy vehicular crashes have been one of the main causes of fatal injuries in Australia,and this raises safety concerns for transport authorities,insurance companies,and emergency services.Although there have been several potential attempts to identify the factors contributing to heavy vehicle crashes and injury severity,it is still necessary to reduce the number of traffic crashes and lower the fatality rate involving heavy vehicles.The aims of this study were investigating the effects of heavy trucks’presence in accidents on the injury severity level sustained by the vehicle driver and detecting the contributing factors that lead to specific injury severity levels.Fixed-and random-parameter ordered probit and logit models were applied for predicting the likelihood of three injury severity categories severe,moderate,and no injury based on data from crashes caused by heavy trucks in Victoria,Australia in 2012-2017.The results showed that the random-parameter ordered probit model performed better than the other models did.Twenty variables(i.e.,factors)were found to be significant,and 12 of them were found to have random parameters that were normally distributed.Since some of the investigated factors had different effects on the type of injury severity in Australia,this paper does not recommend generalizing the findings from other case studies.Based on the findings,Victoria state authorities can have insight and enhanced understanding of the specific factors that lead to various types of injury severity involving heavy trucks.Consequently,the safety of all road users,including heavy vehicle drivers,can be enhanced.展开更多
China’s traffic safety attracts increasing research interest.Official data show that crashes in the western region of China are more severe than those in the eastern region.However,research on crash severity in weste...China’s traffic safety attracts increasing research interest.Official data show that crashes in the western region of China are more severe than those in the eastern region.However,research on crash severity in western China is scarce.This study applied a hierarchical Bayesian logistic model to examine the significant factors related to crash and vehicle/driver levels and their heterogeneous impacts on the severity of drivers’ injury.Crash data were collected from Lintao,a rural mountainous county in western China.A variable was proposed to measure the relative difference between the crashworthiness of one vehicle and the aggressivity of the other vehicle in the mixed traffic flow.Results indicated that the majority of the total variance was induced by between-crash variance,showing the suitability of the utilized hierarchical modeling approach.One crash-level variable and six vehicle/driver-level variables,namely,road type,compatibility difference,age,vehicle type,drunk driving,driving unregistered vehicle,and driving years,significantly affected modeling drivers’ injury severities.Among these variables,road type(national and provincial),age(young and senior drivers),driving unregistered vehicle,and drunk driving tended to increase the odds of crash-related mortality.Driving years(new drivers with less than six years of driving experience) and vehicle type(heavy vehicle) were likely to decrease the probability of fatal outcomes.Compatibility difference was relatively significant,and the possibilities of mortality in single vehicle crashes were higher than those inmultivehicle and pedestrian-involved crashes.The developed methodology and estimation results provided insights into the internal mechanism of rural crashes and effective countermeasures to prevent rural crashes.展开更多
In the era of emerging technologies, the transportation system is witnessing the introduction of innovative mobility services, such as autonomous vehicles, which possess unique service features that cannot be seen fro...In the era of emerging technologies, the transportation system is witnessing the introduction of innovative mobility services, such as autonomous vehicles, which possess unique service features that cannot be seen from conventional travel modes. To facilitate the understanding of the behavioral impacts and the adoption of innovative mobilities, a novel binary weibit model with an oddball alternative (BW-O) is developed for the binary choice between conventional and emerging mobilities. The BW-O model explicitly considers the unprecedented (or unique) service features of emerging travel modes while retaining the closed-form choice probability. This study empirically illustrates the application of the BW-O model in the mode choice context. The desirable properties of the BW-O model compared to the existing binary choice models are discussed both theoretically and empirically. In the binary mode choice problem with an emerging travel mode, the unique service features of the emerging mode can lead to the “oddball” effect and “superstar” effect, which play a critical role in the travel behavior and mode adoption. The BW-O model inherently captures both effects by considering a higher perception variance for the emerging mode and asymmetric choice probabilities between different modes. Thus, as revealed by the empirical results, the BW-O model outperforms the basic binary weibit model in terms of both model fit and predictive power. The developed BW-O model is not only applicable to the mode choice problem in transportation systems, but also opens a door for more general class-imbalanced binary choice contexts where an alternative has additional attractiveness and asymmetric choice probability.展开更多
The effect of sealed or unsealed road pavements on motorist’s injury severities has not been extensively explored.This study collected a four-year crash dataset(2015–2018)from South Australia to explore this issue.T...The effect of sealed or unsealed road pavements on motorist’s injury severities has not been extensively explored.This study collected a four-year crash dataset(2015–2018)from South Australia to explore this issue.The data shows 3,812 and 1,086 crashes at sealed and unsealed pavement surfaces,respectively,during those years.This study examines the consequence of sealed and unsealed pavements on driver injury severity outcomes of motor vehicle crashes.A mixed logit model was developed by accounting for heterogeneity in means and variances of the random parameters.The variables were distributed among several categories:driver,temporal,spatial,roadway characteristics,crash type,vehicle type,and vehicle movement.Four random parameters were observed in the sealed model,whereas five parameters were in the unsealed one.Moreover,the sealed pavements model showed substantial heterogeneity in means of four of the random parameters,while the unsealed pavements model has some heterogeneity in both means and variances of some of the random parameters.Marginal effect results indicate that two indicator variables have enlarged the likelihood of driver severe injury consequences in sealed,alcohol involvement and posted speed limit>100 km/hr.Additionally,four other significant variables sustain the probability of severe injury outcomes at unsealed pavement like male drivers,middle-aged drivers,rollover crash types,and crashes at straight roads.Based on these variables,various countermeasures were recommended to enhance the safety of both types of pavements.展开更多
Young driver crashes are over represented in any country’s crash statistics.This problem is more acute in developing countries where the law enforcement is not strict and the licensing structure is not well developed...Young driver crashes are over represented in any country’s crash statistics.This problem is more acute in developing countries where the law enforcement is not strict and the licensing structure is not well developed.According to World Health Organization(WHO)road crashes are the single greatest cause of death for men aged 15-29 years old.More than 8500 young drivers die each year in the Organization for Economic Co-operation and Development(OECD)countries and the death rates for young drivers are doubled than the older aged drivers.Young driver crashes and deaths cause great economic,social cost on individuals,families and societies.Many research studies have been conducted to find out the causes of crash and deaths.These found that the conventional youth training schemes help young learner to develop their driving skills and knowledge,meanwhile they do not help to gain real road driving experience.Research shows that the lack of driving experience,higher order perception and maturity increase young driver crash exposure.To this end,Graduated Driver Licensing System(GDLS)have been developed.GDLS helps young drivers to focus on road driving experience and it divided the whole licensing process into different phases.It also helps the young drivers to get supervised driving experience which help them to accumulate driving hours to get the provisional license.The GDLS helps not only in gaining experience in driving but also in developing the higher order perception(hazard perception)which is very much needed during driving.This paper discusses a number of driver’s licensing systems and training programs and highlights the need for a licensing system that focus not only on the development of better hazard perception and understanding the road environment for young drivers but also on some other factors that affect road safety.It is argued that the consultation of community concerning the development of a licensing system is essential to minimize road crashes in the youth group as it would guarantee that the young drivers are fully aware of various driving risk factors at training stage rather than the practicing stage.展开更多
基金the Royal Thai Government(RTG)provided financing for this study,as well as a scholarship to assist PhD studies at the Asian Institute of Technology(AIT)The National Science and Technology Development Agency(NSTDA)of Thailand via the Development of High-Quality Research Graduates in Science and Technology Project,a collaboration between NSTDA and AIT, also offers a top-up scholarship for this study
文摘Road transport plays a crucial role in facilitating mobility and the movement of goods,particularly in the Extended Bangkok Metropolitan Region(EBMR),Thailand.This area is undergoing rapid industrialization and urbanization,resulting in significant energy consumption and greenhouse gas(GHG)emissions.This study examined the relationships among individual socioeconomic factors,travel characteristics,and energy consumption characteristics and their impacts on GHG emissions from road transport.The path analysis technique was applied to identify the key driving factors and their causal relationships.The data were collected through 1600 questionnaire surveys with road drivers in representative areas of the EBMR from December 2022 to May 2023.The results revealed that individual socioeconomic factors significantly influenced GHG emissions from road transport.Among the drivers,factors such as income,age,education,and driving experience indirectly influenced travel characteristics and energy consumption characteristics,impacting GHG emissions.Similarly,individual socioeconomic factors affected the travel characteristics of tourists and personal travelers.Driving experience was a crucial factor for public road transport and freight vehicle drivers,influencing travel characteristics and contributing to GHG emissions.These findings highlight the importance of key policy recommendations,such as promoting the adoption of electric vehicles,optimizing public transport,incentivizing low-emission tourism,and modernizing freight transport with clean technologies,to enhance efficiency,reduce emissions,and support regional sustainability.This study provides policy-makers with insights into the key factors influencing GHG emissions across different driving factors,revealing how individual socioeconomic factors impact travel characteristics and energy consumption characteristics.The findings will inform the development of targeted emission reduction strategies and sustainable transport policies.
基金Supported by National Natural Science Foundation of China under Grant No.10675060the Doctoral Foundation of Ministry of Education of China under Grant No.2002055009
文摘A simple model for a set of integrate-and-fire neurons based on the weighted network is introduced. By considering the neurobiological phenomenon in brain development and the difference of the synaptic strength, we construct weighted networks develop with link additions and followed by selective edge removal. The network exhibits the small-world and scale-free properties with high network efficiency. The model displays an avalanche activity on a power-law distribution. We investigate the effect of selective edge removal and the neuron refractory period on the self-organized criticality of the system.
基金the National Natural Science Foundation of China(Nos.11632007 and 11472085)the Project of Promoting the Basic Ability of Scientific Research of Young and Middle-aged Teachers in Universities of Guangxi(No.2019KY1365),which are gratefully acknowledged.
文摘The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain level.Symmetrical tension-compression cycle tests are performed on pure copper specimens to observe the inhomogeneous distribution of slip deformation and its evolution with cycle number.Cyclic hardening process and stable hysteretic behavior of pure copper under cyclic loading are simulated by applying a crystal plasticity constitutive model including nonlinear kinematic hardening associated with the polycrystalline representative volume element(RVE)constructed by Voronoi tessellation.Inhomogeneous deformation processes of materials under six different strain amplitudes are simulated by 1600 cycles,respectively.We discuss the variation law of the inhomogeneous meso-deformation distribution of material with the increase in cycle number,and research the rationality of characterizing the inhomogeneous deformation distribution and variation with the statistical standard deviation of the micro-longitudinal strain or the statistical average of the first principal strain based on the statistical analysis of the inhomogeneous deformation of the polycrystalline RVE model during the cycling process.It is found that these two parameters are related to and approximately inversely proportional to the length of measuring gauge.
文摘The permanent deformation (rutting) of pavement is a major distress in flexible pavement. It is related to vehicles properties and/or pavement materials and conditions. This article presents an extensive experimental investigation in order to compare between the aggregate gradation according to Superpave and Marshall methods of asphalt concrete mix design on pavement rutting and to examine the sensitivity of rutting resistance to aggregate gradation. A wheel truck machine has been used for measurement of pavement rutting (permanent deformation). The tests were carried out at two controlled different air temperature 55℃ and 25℃. The results obtained showed that the adopting of aggregate gradation procedure of Superpave method of pavement mix design for Marshall method of asphalt concrete mix design can reduce the pavement rutting by about 50%. This achievement may be related to missing of three sieves in aggregate gradation procedure of Marshall method which controls rounded and finer aggregate particles. These sieves provide more continuity for aggregate gradation to ensure filling unnecessary gaps and produce more contact points between the aggregates in Hot Mix Asphalt (HMA). The outputs of the research support modifying Marshall method of asphalt concrete mix design by adopting aggregate gradation proposed in Superpave method. The results of study also showed that the coarser aggregate provided more resistance to pavement rutting.
文摘The Tianjin Port is the largest man-made port in China. Since the navigation channel of the Tianjin Port is constructed by dredging, a very important problem, as many people concerned, is the submarine slope stability. As the environment on land is different from that in submarine, it is necessary to evaluate the influence of the environmental loading, such as wave and tide, on the stability of navigation channel slope. In the present study, based on the observed results, the characteristics of the navigation channel slope are summarized, and the causes of creating the special slope shape are analyzed. The ioles of waves and tides are evaluated, and failure mechanics are discussed to helq us predict what will happen in the future.
文摘In the last decade, Brazil was the scene of two of the world’s biggest disasters related to mining tailings dams. The collapse of the Mariana and Brumadinho dams was catastrophic event that brought to light major environmental and humanitarian crises. Facts like this incite debate on the safety of dam construction methods and highlight the need for a broad discussion of dam safety legislation in the country. From the above, this paper promotes a review of various forms of construction of tailings dams and their associated problems, as well as discusses the techniques for soil reinforcement and their construction methods. The work also brings an overview of the Brazilian dams from April to July 2019, tracing the context of the Brazilian tailings dams months after the tragedy of Brumadinho. The methodology includes a robust literature review and discourse analysis. In Brazil, the number of ruptured dams is alarming, especially in the state of Minas Gerais, in which more than 7 have broken in the last two decades. Among the damages, the deaths impact society abruptly and were cataloged 455 deaths, of which 216 correspond to the rupture of the dam of the Córrego do Feijão mine in Brumadinho. To evaluate and diagnose a dam, one should consider ordinance N ° 70,389, 2017 revoked by Resolution ANM n ° 95, of February 7, 2022. In this context, in March 2019, we experienced several disturbing situations regarding dam instability in the state of Minas Gerais, being categorized as risky structures. To exemplify, one can cite dams classified as level 2 risk that became level 3. Due to the above facts, several studies are being conducted to improve soil aspects. For example, we highlight the increase in soil resistance that can be done using commercial and alternative materials available in the environment.
文摘Understanding the factors contributing to CO_(2)emissions is pivotal for informed policy-making and sustainable urban development.This study probes the interconnections between urban attributes,transportation patterns,and socioeconomic factors concerning CO_(2)emissions using Decision Tree analysis across a substantial dataset of US zip codes.The dataset was carefully prepared to ensure accuracy and relevance,considering temporal,geographical,and socioeconomic heterogeneity.The Decision Tree algorithm was applied iteratively to evaluate variable interactions and identify critical thresholds that influence carbon emissions.The findings of this study shed light on the key drivers of CO_(2)emissions across US zip codes.The analysis reveals significant variations in the relative importance of different factors in different regions,emphasizing the need for localized and tailored strategies to address carbon reduction targets effectively.The research provides a more holistic understanding that can drive effective urban planning and energy policies,ultimately contributing to the global effort to reduce carbon emissions and combat climate change.The findings from this research underscore the importance of multidisciplinary approaches in addressing environmental challenges and highlight the necessity for continuous innovation in analytical methodologies to keep pace with the evolving urban landscapes.
文摘The accessibility of a destination-based transportation system is defined to quantify the performance of transportation systems which access a distinct destination. The access cost is used to reflect the utility of the transportation system including the fatigue and inconvenience in the total cost. The cost is quan- tified by two coefficients which represent the different characteristics of various people. The average cost and the income-relative accessibility are used to describe various aspects of the accessibility and to evaluate the accessibility of a destination-based system. A case study uses data from the Kunming transportation system to evaluate the accessibility of the present city airport. The calibrated coefficients are then used to evaluate the transportation system to the new Kunming international airport. The results show that this transportation accessibility evaluation can be combined with transportation planning to study transportation sub-systems.
基金the National Natural Science Foundation of China (No. 70571046)
文摘The paper analyzes the equity of road resources distribution in urban areas by modeling the competitive relationship among different road users. A logistic model is used to describe the development of different traffic modes in the transportation network. The system is similar to the species competition model, so a two-species model is used to analyze the relationship between users based on the stability of the equilibrium points. The Lotka-Volterra model is then used to describe the multi-species cases with numerical examples, showing that this model can describe the effects of the road space distribution on the competitive user relationships. Policy makers must ensure the equity of road resources distribution so that each urban transportation mode is properly developed for sustainable social development.
基金Supported by the National Natural Science Foundation of China(10472132)
文摘Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall, cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical, homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory. The boundary conditions and continuity conditions for the solution of the problem were found. The forcedeformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained. The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip, depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness, and numerical simulation is a powerful method for determining plant cell mechanical properties.
文摘Road maintenance work brings costs to the government and delays to users. The setting up of work zones often leads to severe congestion during peak hours, especially in busy urban areas. A road maintenance delay model is presented here that includes consideration of excessive traffic flow and non-motorists. Atrial-and-error method is used to find the optimal work zone length and the best work starting time to minimize the total cost of maintenance and delays. A numerical example with a sensitivity analysis is also given. The results show that optimal starting time is not sensitive to the flow speed and the increase of work zone speeds sharply reduces the total cost when the road is congested.
基金supported by The National Natural Science Foundation of China (Grant No.52072214 and Grant No.71871123)Global Road Safety Partnership (GRSP) (Grant No.CHNXX-RD16-1188).
文摘The helmet of riders of electric bicycles plays an important role in reducing injuries and deaths in traffic accidents.This paper conducts a questionnaire survey,data analysis and modelling to investigate the influencing factors of electric bicycle helmet wearing.First,living area,gender,age,marital status and education level are selected as independent variables for data analysis.The factor analysis divides the sentiments of electric bicyclists for wearing helmets into four aspects:safety perception,practical sensation,satisfaction perception and emergency perception,and ordinal multiple logistic models are built to analyse the influencing factors.The result shows that people aged 18−25,26−35,36−45 and 46−55 are 1.3,1.8,2.0 and 2.3 times more likely,respectively,to have at least a grade higher safety perception than those aged 56 and over;men are 0.77 times more likely than women to feel at least one grade higher about the practical perception and 1.48 times more than women about the satisfaction perception;people with primary school,junior high school,senior high school,junior college and bachelor’s degree education are 1.64,2.44,1.50,1.70 and 1.55 times more likely,respectively,than people with a master’s degree to feel at least one grade higher about the satisfaction perception.
基金the National High-Tech Research and Development (863) Program of China (No. 2007AA11Z202)
文摘Currently applied prediction methods of regional freight traffic and freight ton-kilometer forecasting were analyzed using typical Chinese regional goods transportation characteristics. The review of prediction methods showes that practical planning experts tend to apply the traditional methods which are easier to implement. The comparison also demonstrates that a combination of traditional methods is more effective than the simple models for practical planning. Research using the statistical data for the Yangtze Delta, Pearl River Delta, and Bohai Rim areas shows that ignoring differences between transport modes impacts the prediction accuracy. The four main transport modes suit different methods. The results show that the power model is better for railways, and the linear model is better for highways and waterways. Thus a combined model gives better results for all modes. The results for regional systems can be generalized to national transportation systems.
基金supported by National Key Technology R&D Program(No.2012 BAJ05B04)Hang Lung Center for Real Estate,Tsinghua UniversityCollaborative Innovation Center for Capital World City's Smooth Traffic Construction
文摘This paper reports the effects of using an ＂odd and even＂ traffic restriction policy in Beijing during the 2008 Olympic Games. Based on data from 529 traffic detectors on the expressway network and some main arterials in Beijing, China, a comparative analysis has been carried out on the following parameters： the total traffic volume within the expressway network, the total traffic volume on different ring expressways, the traffic volume and speed of a freeway segment, and an arterial street before and after the implementation of the traffic restriction policy. The results show that during the traffic restriction period, although more than 50% of vehicles were forbidden to travel in Beijing, the traffic volume was only reduced by 20%-40% while the travel speed had been increased by 10%-20%. This suggests that such traffic restriction policy may be an effective shortterm management measure in dealing with increased transportation demand and congestion during major events, such as the Olympic Games. Results also indicate that vehicle travel demand does not decrease with the same proportion as the total vehicles forbidden, at least for the expressway and main arterials in a city.
文摘Drowsy driving has received comparatively less attention in traffic safety literature when compared to other safety issues,despite its devastating impact on society in terms of human life lost and associated economic burdens.Therefore,this significant safety threat requires a thorough investigation.To address the temporal instability of factors contributing to crashes involving drowsy drivers,this paper divides the crash data into four time periods while capturing unobserved heterogeneity in the means and variances of random parameters.To explore the determinants affecting the severity of injuries sustained by drowsy drivers involved in single-vehicle crashes,injury outcomes are categorized into three groups:serious,moderate,and no injuries.Using four years of crash data from the state of Washington between 2013 and 2016,a wide range of factors were examined,including driver characteristics,roadway conditions,crash characteristics,vehicle conditions,lighting conditions,and temporal factors.The estimation results reveal that there is temporal instability in terms of the effect of determinants on injury severity across the years.However,some factors exhibit stable effects,such as female drivers,sober drivers,and non-hit-and-run crashes.Based on the findings of this study,decision-makers,traffic engineers,and traffic authorities can gain valuable knowledge and insights into the factors contributing to drowsy-related crashes,enabling them to make informed recommendations for safety countermeasures.
文摘Despite the importance of heavy vehicles in Australia’s transportation system,little is known on the factors influencing injury severity from accidents involving a single heavy vehicle.Heavy vehicular crashes have been one of the main causes of fatal injuries in Australia,and this raises safety concerns for transport authorities,insurance companies,and emergency services.Although there have been several potential attempts to identify the factors contributing to heavy vehicle crashes and injury severity,it is still necessary to reduce the number of traffic crashes and lower the fatality rate involving heavy vehicles.The aims of this study were investigating the effects of heavy trucks’presence in accidents on the injury severity level sustained by the vehicle driver and detecting the contributing factors that lead to specific injury severity levels.Fixed-and random-parameter ordered probit and logit models were applied for predicting the likelihood of three injury severity categories severe,moderate,and no injury based on data from crashes caused by heavy trucks in Victoria,Australia in 2012-2017.The results showed that the random-parameter ordered probit model performed better than the other models did.Twenty variables(i.e.,factors)were found to be significant,and 12 of them were found to have random parameters that were normally distributed.Since some of the investigated factors had different effects on the type of injury severity in Australia,this paper does not recommend generalizing the findings from other case studies.Based on the findings,Victoria state authorities can have insight and enhanced understanding of the specific factors that lead to various types of injury severity involving heavy trucks.Consequently,the safety of all road users,including heavy vehicle drivers,can be enhanced.
基金The research reported in this paper is part of the project supported by the National Natural Science Foundation of China (71871123)。
文摘China’s traffic safety attracts increasing research interest.Official data show that crashes in the western region of China are more severe than those in the eastern region.However,research on crash severity in western China is scarce.This study applied a hierarchical Bayesian logistic model to examine the significant factors related to crash and vehicle/driver levels and their heterogeneous impacts on the severity of drivers’ injury.Crash data were collected from Lintao,a rural mountainous county in western China.A variable was proposed to measure the relative difference between the crashworthiness of one vehicle and the aggressivity of the other vehicle in the mixed traffic flow.Results indicated that the majority of the total variance was induced by between-crash variance,showing the suitability of the utilized hierarchical modeling approach.One crash-level variable and six vehicle/driver-level variables,namely,road type,compatibility difference,age,vehicle type,drunk driving,driving unregistered vehicle,and driving years,significantly affected modeling drivers’ injury severities.Among these variables,road type(national and provincial),age(young and senior drivers),driving unregistered vehicle,and drunk driving tended to increase the odds of crash-related mortality.Driving years(new drivers with less than six years of driving experience) and vehicle type(heavy vehicle) were likely to decrease the probability of fatal outcomes.Compatibility difference was relatively significant,and the possibilities of mortality in single vehicle crashes were higher than those inmultivehicle and pedestrian-involved crashes.The developed methodology and estimation results provided insights into the internal mechanism of rural crashes and effective countermeasures to prevent rural crashes.
基金National Natural Science Foundation of China(72071174)Research Grants Council of the Hong Kong Special Administrative Region(PolyU 15222221 and PolyU 15221922)+1 种基金Smart Cities Research Institute(CDA9)and the Research Institute of Land and Space(1-CD7N)at the Hong Kong Polytechnic Universitythe Chiang Mai University in Thailand.
文摘In the era of emerging technologies, the transportation system is witnessing the introduction of innovative mobility services, such as autonomous vehicles, which possess unique service features that cannot be seen from conventional travel modes. To facilitate the understanding of the behavioral impacts and the adoption of innovative mobilities, a novel binary weibit model with an oddball alternative (BW-O) is developed for the binary choice between conventional and emerging mobilities. The BW-O model explicitly considers the unprecedented (or unique) service features of emerging travel modes while retaining the closed-form choice probability. This study empirically illustrates the application of the BW-O model in the mode choice context. The desirable properties of the BW-O model compared to the existing binary choice models are discussed both theoretically and empirically. In the binary mode choice problem with an emerging travel mode, the unique service features of the emerging mode can lead to the “oddball” effect and “superstar” effect, which play a critical role in the travel behavior and mode adoption. The BW-O model inherently captures both effects by considering a higher perception variance for the emerging mode and asymmetric choice probabilities between different modes. Thus, as revealed by the empirical results, the BW-O model outperforms the basic binary weibit model in terms of both model fit and predictive power. The developed BW-O model is not only applicable to the mode choice problem in transportation systems, but also opens a door for more general class-imbalanced binary choice contexts where an alternative has additional attractiveness and asymmetric choice probability.
文摘The effect of sealed or unsealed road pavements on motorist’s injury severities has not been extensively explored.This study collected a four-year crash dataset(2015–2018)from South Australia to explore this issue.The data shows 3,812 and 1,086 crashes at sealed and unsealed pavement surfaces,respectively,during those years.This study examines the consequence of sealed and unsealed pavements on driver injury severity outcomes of motor vehicle crashes.A mixed logit model was developed by accounting for heterogeneity in means and variances of the random parameters.The variables were distributed among several categories:driver,temporal,spatial,roadway characteristics,crash type,vehicle type,and vehicle movement.Four random parameters were observed in the sealed model,whereas five parameters were in the unsealed one.Moreover,the sealed pavements model showed substantial heterogeneity in means of four of the random parameters,while the unsealed pavements model has some heterogeneity in both means and variances of some of the random parameters.Marginal effect results indicate that two indicator variables have enlarged the likelihood of driver severe injury consequences in sealed,alcohol involvement and posted speed limit>100 km/hr.Additionally,four other significant variables sustain the probability of severe injury outcomes at unsealed pavement like male drivers,middle-aged drivers,rollover crash types,and crashes at straight roads.Based on these variables,various countermeasures were recommended to enhance the safety of both types of pavements.
文摘Young driver crashes are over represented in any country’s crash statistics.This problem is more acute in developing countries where the law enforcement is not strict and the licensing structure is not well developed.According to World Health Organization(WHO)road crashes are the single greatest cause of death for men aged 15-29 years old.More than 8500 young drivers die each year in the Organization for Economic Co-operation and Development(OECD)countries and the death rates for young drivers are doubled than the older aged drivers.Young driver crashes and deaths cause great economic,social cost on individuals,families and societies.Many research studies have been conducted to find out the causes of crash and deaths.These found that the conventional youth training schemes help young learner to develop their driving skills and knowledge,meanwhile they do not help to gain real road driving experience.Research shows that the lack of driving experience,higher order perception and maturity increase young driver crash exposure.To this end,Graduated Driver Licensing System(GDLS)have been developed.GDLS helps young drivers to focus on road driving experience and it divided the whole licensing process into different phases.It also helps the young drivers to get supervised driving experience which help them to accumulate driving hours to get the provisional license.The GDLS helps not only in gaining experience in driving but also in developing the higher order perception(hazard perception)which is very much needed during driving.This paper discusses a number of driver’s licensing systems and training programs and highlights the need for a licensing system that focus not only on the development of better hazard perception and understanding the road environment for young drivers but also on some other factors that affect road safety.It is argued that the consultation of community concerning the development of a licensing system is essential to minimize road crashes in the youth group as it would guarantee that the young drivers are fully aware of various driving risk factors at training stage rather than the practicing stage.
