共查询到7条相似文献,搜索用时 15 毫秒
1.
In this paper, we study the impact of using a new intelligent vehicle technology on the performance and total cost of a European port, in comparison with existing vehicle systems like trucks. Intelligent autonomous vehicles (IAVs) are a new type of automated guided vehicles (AGVs) with better maneuverability and a special ability to pick up/drop off containers by themselves. To identify the most economical fleet size for each type of vehicle to satisfy the port’s performance target, and also to compare their impact on the performance/cost of container terminals, we developed a discrete-event simulation model to simulate all port activities in micro-level (low-level) details. We also developed a cost model to investigate the present values of using two types of vehicle, given the identified fleet size. Results of using the different types of vehicles are then compared based on the given performance measures such as the quay crane net moves per hour and average total discharging/loading time at berth. Besides successfully identifying the optimal fleet size for each type of vehicle, simulation results reveal two findings: first, even when not utilising their ability to pick up/drop off containers, the IAVs still have similar efficacy to regular trucks thanks to their better maneuverability. Second, enabling IAVs’ ability to pick up/drop off containers significantly improves the port performance. Given the best configuration and fleet size as identified by the simulation, we use the developed cost model to estimate the total cost needed for each type of vehicle to meet the performance target. Finally, we study the performance of the case study port with advanced real-time vehicle dispatching/scheduling and container placement strategies. This study reveals that the case study port can greatly benefit from upgrading its current vehicle dispatching/scheduling strategy to a more advanced one. 相似文献
2.
An Application of the Hierarchical Fuzzy Process to Container Port Competition: Policy and Strategic Implications 总被引:1,自引:0,他引:1
This paper aims to empirically identify the competitiveness of container ports in Asia by examining factors influencing the
perceived competitive edge of each port using the Hierarchical Fuzzy Process, a method embracing human knowledge and/or judgement
into a mathematical framework. This analysis is unique in that the ‘human-perceived’ competitiveness on Asian container ports
is examined under the quantifiable framework. The findings reveal that Singapore is the most competitive port among the sampled
ports. Moreover, the methodology employed here shows the potential to be applicable to other transport and logistics related
service industries. 相似文献
3.
Alexandra Hyard 《Transportation Research Part A: Policy and Practice》2012,46(4):707-719
Made compulsory in France for major transport infrastructures, cost-benefit analysis is constantly being improved to achieve the best socio-economic evaluation possible. According to the philosopher and economist Amartya Sen, this analysis should meet two requirements: one ethical, the other democratic. We will examine the evaluation procedure in France and highlight the gap between its officially more democratic character and its still insufficiently ethical character, from the viewpoint of this dual requirement. 相似文献
4.
Paulus Teguh Aditjandra Xinyu CaoCorinne Mulley 《Transportation Research Part A: Policy and Practice》2012,46(1):22-32
The objective of this study is to explore whether changes in neighbourhood characteristics bring about changes in travel choice. Residential self-selection is a concern in the connections between land-use and travel behaviour. The recent literature suggests that a longitudinal structural equations modelling (SEM) approach can be a powerful tool to assess the importance of neighbourhood characteristics on travel behaviour as opposed to the attitude-induced residential self-selection. However, the evidence to date is limited to particular geographical areas and evidence from one country might not be transferrable to another because of differences in land-use patterns and land-use policies. The paper is to address the gap by extending the evidence using British data. The case study is based on the metropolitan area of Tyne and Wear, North East of England, UK. A SEM is applied to 219 respondents who reported residential relocation. The results identify that neighbourhood characteristics do influence travel behaviour after controlling for self-selection. For instance, the more people are exposed to public transport access, the more likely they drive less. Neighbourhood characteristics also impact through their influence on car ownership. A social environment with vitality also reduces the amount of private car travel. These findings suggest that land-use policies at neighbourhood level can play an important role in reducing driving. 相似文献
5.
A commuting model for the analysis of the impacts of a tramway project: application to the Lens area
Road congestion is not only an issue for major European urban agglomerations, but also for smaller ones. It is also the case of the Lens urban area, where car use is much higher than the average for medium-sized urban agglomerations in France. Local authorities put forward tramway projects to deal with the strongly negative externalities of congestion: travel time losses and pollution. To analyse its medium-term impact, we have developed a commuting with congestion model, inspired by the four-step traditional model, but with data made available from an origin–destination matrix. The results are encouraging but insufficient, and it is necessary to adopt supplementary measures in order to retrieve and justify the sizeable investments needed. Some measures prove to be very efficient, such as parking fees and urban tolls. Other measures, such as the subsidization of public transport, are partially efficient since they have an impact mainly on intra-urban commutes. 相似文献
6.
In transportation studies, variables of interest are often influenced by similar factors and have correlated latent terms
(errors). In such cases, a seemingly unrelated regression (SUR) model is normally used. However, most studies ignore the potential
temporal and spatial autocorrelations across observations, which may lead to inaccurate conclusions. In contrast, the SUR
model proposed in this study also considers these correlations, making the model more behaviorally convincing and applicable
to circumstances where a three-dimensional correlation exists, across time, space, and equations. An example of crash rates
in Chinese cities is used. The results show that incorporation of spatial and temporal effects significantly improves the
model. Moreover, investment in transportation infrastructure is estimated to have statistically significant effects on reducing
severe crash rates, but with an elasticity of only −0.078. It is also observed that, while vehicle ownership is associated
with higher per capita crash rates, elasticities for severe and non-severe crashes are just 0.13 and 0.18, respectively; much
lower than one. The techniques illustrated in this study should contribute to future studies requiring multiple equations
in the presence of temporal and spatial effects.
Ms. Xiaokun Wang is a doctoral student in the Department of Civil, Architectural and Environmental Engineering at the University of Texas at Austin. She received her B.S. and M.S. degrees at Tsinghua University, China. Her research topics range from travel demand modeling and integrated land use-transportation planning, to spatial econometrics, network analysis, and traffic safety analysis. She is a fellow of the International Road Federation. Dr. Kara Kockelman is a Associate Professor of Civil, Architectural & Environmental Engineering and the William J. Murray Jr. Fellow at the University of Texas, Austin. She holds a PhD, MS, and BS in Civil Engineering, a Masters of City Planning, and a minor in Economics from the University of California at Berkeley. She is Chair of the Transportation Research Board’s Committee on Travel Survey Methods. Her primary research interests include the statistical modeling of urban systems (including models of travel behavior, trade, and location choice), economic impacts of transport policy, crash occurrence and consequences, and transport policy-making. 相似文献
Kara M. Kockelman (Corresponding author)Email: |
Ms. Xiaokun Wang is a doctoral student in the Department of Civil, Architectural and Environmental Engineering at the University of Texas at Austin. She received her B.S. and M.S. degrees at Tsinghua University, China. Her research topics range from travel demand modeling and integrated land use-transportation planning, to spatial econometrics, network analysis, and traffic safety analysis. She is a fellow of the International Road Federation. Dr. Kara Kockelman is a Associate Professor of Civil, Architectural & Environmental Engineering and the William J. Murray Jr. Fellow at the University of Texas, Austin. She holds a PhD, MS, and BS in Civil Engineering, a Masters of City Planning, and a minor in Economics from the University of California at Berkeley. She is Chair of the Transportation Research Board’s Committee on Travel Survey Methods. Her primary research interests include the statistical modeling of urban systems (including models of travel behavior, trade, and location choice), economic impacts of transport policy, crash occurrence and consequences, and transport policy-making. 相似文献
7.
An agent‐based simulation model to assess the impacts of introducing a shared‐taxi system: an application to Lisbon (Portugal) 下载免费PDF全文
This paper presents a new concept of urban shared‐taxi services. The proposed system has a new organisational design and pricing scheme that aims to use the capacity in traditional taxi services in a more efficient way. In this system, a taxi acting in ‘sharing’ mode offers lower prices to its clients, in exchange for them to accept sharing the vehicle with other persons who have compatible trips (time and space). The paper proposes and tests an agent‐based simulation model in which a set of rules for space and time matching between a request of a client and the candidate shared taxis is identified. It considers that the client is only willing to accept a maximum deviation from his or her direct route and establishes an objective function for selecting the best candidate taxi. The function considers the minimum travel time combination of pickup and drop‐off of all the pool of clients sharing each taxi while allowing to establish a policy of bonuses to competing taxis with certain number of occupants. An experiment for the city of Lisbon is presented with the objectives of testing the proposed simulation conceptual model and showing the potential of sharing taxis for improving mobility management in urban areas. Results show that the proposed system may lead to significant fare and travel time savings to passengers, while not jeopardising that much the taxi revenues. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献