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transportation-network
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Total 71 records
Network Pricing Using Path Flow Information
, M.Sc. Thesis Sharif University of Technology ; Zokaei Aashtiani, Hedayat (Supervisor)
Abstract
The toll pricing problem has been investigated in the literature for the cases of link, cordon, and facility (bridge, tunnel and etc.) pricing. Taking advantages of new technologies, nowadays it is possible to track the path of individual vehicles and collect the tolls by means of electronic devices. In this regard, we concerned the problem of path pricing. In this thesis, a variety of models for path pricing is proposed, the models are solved for the Hearn network and the results are compared to the results of link pricing models. In addition to the models, one exact solution method and two heuristic methods are proposed for the model of path pricing with the minimum total toll....
Solving the minimum toll revenue problem in real transportation networks
, Article Optimization Letters ; 2014 ; ISSN: 18624472 ; Aashtiani, H. Z ; Sharif University of Technology
Abstract
As a means to relieve traffic congestion, toll pricing has recently received significant attention by transportation planners. Inappropriate use of transportation networks is one of the major causes of network congestion. Toll pricing is a method of traffic management in which traffic flow is guided to proper time and path in order to reduce the total delay in the network. This article investigates a method for solving the minimum toll revenue problem in real and large-scale transportation networks. The objective of this problem is to find link tolls that simultaneously cause users to efficiently use the transportation network and to minimize the total toll revenues to be collected. Although...
A nonlinear model for location-allocation-routing problem in transportation network with intelligent travel times
, Article International Journal of Operational Research ; Volume 29, Issue 3 , 2017 , Pages 400-431 ; 17457645 (ISSN) ; Mahdavi Amiri, N ; Mahdavi, I ; Sharif University of Technology
Inderscience Enterprises Ltd
2017
Abstract
We provide a mixed-integer nonlinear programming (MINLP) model for a location-allocation-routing problem in a transportation network with links carrying the travel times among the nodes in the network. The travel time between two nodes is considered to be intelligent, that is, since the travelling population in a link can affect the travel time, here we consider the impact of the travelling population on the travel time of the link. This way, depending on how the population is distributed in the network, the travel times of the links may change. The problem is to find an optimal locations of server node(s), allocation of existing demand nodes in the network to the server(s) and allocation of...
Post-disaster Resilience of Transportation Network using Route Diversity Factor
, M.Sc. Thesis Sharif University of Technology ; Nasiri, Habibollah (Supervisor)
Abstract
Natural hazards such as earthquake take many lives each year and cause significant damages to infrastructures such as transportation networks. Whether after occurrence of a natural disaster like storm in order to evacuate, or after an abrupt event such as earthquake in order to provide emergency measures, a transportation network should maintain its functionality and performance in an acceptable degree and should recover in an effectively short period of time. In this study, the link or the set of links which their removal causes significant damage to the transportation network are identified. A specific index (N-Q index) has been used to describe the performance of the network. In addition,...
Improving the Stability of an Urban Traffic Network with Limited Data by Using Percolation Theory and Dynamic Clustering
, M.Sc. Thesis Sharif University of Technology ; Amini, Zahra (Supervisor)
Abstract
One of the most vital aspects of understanding the traffic phenomenon is scrutinizing the traffic transition status, such as the transition from free flow to congestion. The Percolation Theory is a renowned theory focusing on analyzing various network types to detect the critical zones, which are the zones including links that are important to control to improve stability. By calculating the quality indices of network links, the Percolation Theory can simulate the traffic percolation propagation in the network and determine possible critical zones for further analysis. Most studies in this field assume access to data of several traffic parameters for the entire transportation network, such...
Geospatial Analysis on Tehran Transportation Network
, M.Sc. Thesis Sharif University of Technology ; Sarbazi-Azad, Hamid (Supervisor)
Abstract
A city is a complex system which consists of many interactive sub-systems. It is affected by diverse factors including governmental land policies, population growth, market behavior and transportation infrastructure. Traffic congestion is one of the most critical challenges of transport infrastructure which became everyday occurrence in the last decades. The traffic planners and traffic engineers have faced real obstacles due to the growth of motorization and the resulted external consequences. Furthermore the capacity of the traffic networks saturates during rush hours. Generally, network transport performance can be improved in two ways, optimizing network structure (Hard Strategy) or...
Cloud manufacturing service selection optimization and scheduling with transportation considerations: mixed-integer programming models
, Article International Journal of Advanced Manufacturing Technology ; 2017 , Pages 1-28 ; 02683768 (ISSN) ; Houshmand, M ; Van Woensel, T ; Mutlu, N ; Sharif University of Technology
Abstract
Cloud manufacturing is an emerging service-oriented manufacturing paradigm that integrates and manages distributed manufacturing resources through which complex manufacturing demands with a high degree of customization can be fulfilled. The process of service selection optimization and scheduling (SSOS) is an important issue for practical implementation of cloud manufacturing. In this paper, we propose new mixed-integer programming (MIP) models for solving the SSOS problem with basic composition structures (i.e., sequential, parallel, loop, and selective). Through incorporation of the proposed MIP models, the SSOS with a mixed composition structure can be tackled. As transportation is...
Cloud manufacturing service selection optimization and scheduling with transportation considerations: mixed-integer programming models
, Article International Journal of Advanced Manufacturing Technology ; Volume 95, Issue 1-4 , 2018 , Pages 43-70 ; 02683768 (ISSN) ; Houshmand, M ; van Woensel, T ; Mutlu, N ; Sharif University of Technology
Springer London
2018
Abstract
Cloud manufacturing is an emerging service-oriented manufacturing paradigm that integrates and manages distributed manufacturing resources through which complex manufacturing demands with a high degree of customization can be fulfilled. The process of service selection optimization and scheduling (SSOS) is an important issue for practical implementation of cloud manufacturing. In this paper, we propose new mixed-integer programming (MIP) models for solving the SSOS problem with basic composition structures (i.e., sequential, parallel, loop, and selective). Through incorporation of the proposed MIP models, the SSOS with a mixed composition structure can be tackled. As transportation is...
Reliability of tehran transportation network during earthquake
, Article Proceedings of the Conference on Traffic and Transportation Studies, ICTTS, 5 August 2008 through 7 August 2008, Nanning ; Volume 322 , 2008 , Pages 428-437 ; 9780784409954 (ISBN) ; Nassiri, H ; Sharif University of Technology
2008
Abstract
The great potential of natural and unnatural events in many countries like Iran along with the strategic role of transportation networks in a country's economic, disaster management in Iran's transportation network, especially in its capital, Tehran, has a great importance. Also transportation networks play an important role in various stages of response to disasters, such as evacuation, search and rescue, and reconstruction missions. Hence, special attention must be paid to transportation networks in any disaster management system. Reliability measures are critical in judging the performance of a transportation system and it is very important to evaluate the performance of the network after...
Solving Network Toll Pricing Problem with Minimum Tollbooth
, M.Sc. Thesis Sharif University of Technology ; Zokaie Ashtiani, Hedayat (Supervisor)
Abstract
Pricing problem in transportation networks focuses on determining tolls that cause travellers, motivated only by their travel costs, to choose routes that would collectively benefit all travellers and results in optimal utilization of transport network resources.This thesis addresses the toll pricing problem in which the objective is to minimize the number of required toll facilities in a transportation network. Minimum tollbooth problem (MINTB) has binary variables and is very difficult to solve. In this thesis a new heuristic approach has been presented for solving MINTB problem. The results show that, this approach is much faster than the existing algorithms and is able to solve real size...
Highway Toll Pricing in Urban Areas
, M.Sc. Thesis Sharif University of Technology ; Zakaei Ashtiani, Hedayat (Supervisor)
Abstract
Inappropriate use of the transportation networks is one of the causes of network congestion. Toll pricing is one of the traffic management tools to mitigate delay and congestion by guiding traffic flow to proper time and route. Efficient use of network facilities is one of transportation planners’ goal and highways are one of the most important facilities in a transportation network. In this study, we investigate the highway toll pricing problem in order to reduce total travel time for the users. We introduce four different strategies to collect toll from highway users. Direct solution methods for large networks faced with the problem of solving time. In this regard, some heuristics methods...
Optimal distribution of the injured in a multi-type transportation network with damage-dependent travel times: Two metaheuristic approaches
, Article Socio-Economic Planning Sciences ; 2018 ; 00380121 (ISSN) ; Mahdavi Amiri, N ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
We study a location-allocation-routing problem for distribution of the injured in a disaster response scenario, considering a three-type transportation network with separate links. A circle-based approach to estimate the impacts of the disaster is presented. After formulating relations for computing the percentage of the injured, the destruction percentage and the damage-dependent travel times, the problem is formulated as an integer nonlinear program. We utilize a genetic algorithm and a discrete version of the imperialist competitive algorithm for solving large problems. An empirical study focused on earthquakes in Tabriz, Iran, illustrates applicability of the proposed model and...
Network Design to Alleviate Chaos in the Transportation Network Flows: Cases of Deterministic and Uncertain Supply
, M.Sc. Thesis Sharif University of Technology ; Pourzahedi, Hossein (Supervisor)
Abstract
Transportation networks are considered as complex systems, and in many cases they behave in such an irregular and unexpected manner. Such complexities cause problems in studying the behavior of these systems. An example of such complexities is chaos in the network flows. On the other hand, the behavior of these networks is highly affected by the incidents like accidents and bad weather. Such events affect the level of service and travel time reliability of the networks. In this research, a dynamical approach to traffic assignment has been chosen to model chaos and uncertainties in the network. By using this approach for modeling flow evolution, edge of chaos and uncertainty in supply and...
Chaotic Network Flows in an Evolutionary Model of Traffic Assignment Based on Speed and Density
, M.Sc. Thesis Sharif University of Technology ; Poorzahedy, Hossein (Supervisor)
Abstract
Chaotic Flow in transportation networks has been the subject of several studies. Evolutionary models have been employed to simulate traffic flows. This study takes advantage of an existing evolutionary model of traffic assignment to show that chaotic phenomena arise when the model’s driving force is speed or density, of traffic flow. It has been observed that drivers show higher sensitivity when the network is more loaded.
Designing a Transportation System to Minimize the Transportation Cost
, M.Sc. Thesis Sharif University of Technology ; Ghasemi Tari, Farhad (Supervisor)
Abstract
Transportation problem is one of the most important parts in supply chain management and it offers great potential to reduce costs and improve service quality. So many research efforts, are considering the optimization of the transportation systems and its related aspects. In this thesis, a transportation system according to a real case study, with the aim of minimizing total cost is considered. It is assumed a fleet of vehicles with limited capacity and different fixed and variable costs are shipping different products from a manufacturing plant to their associated nationwide distribution storages. Certain number of storages or depots with deterministic demand is available and each has a...
Network Design Problem to Prevent Chaotic Flow
, M.Sc. Thesis Sharif University of Technology ; Pourzahedi, Hossein (Supervisor)
Abstract
Two significant features of a transportation network, uncertainty and complexity, might cause some irregular behaviors. One example of such behaviors is chaotic flow in which the transportation system fails to reach equilibrium and people experience different daily travel times. These uncertainties are not controllable in any transportation system and, if not taken into consideration, will result to low levels of service and poor reliability. In this study, an evolutionary traffic assignmet model is used to illustrate when the network reaches bifurcation and chaos. Later, the effects of uncertainty in the parameters of supply and demand is tested on the evolutionary traffic assignment model....
Route Choice Estimation Using Cell Phone Data
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
Knowing the trip information such as paths that travelers prefer to choose is useful for practice in developing certain transportation planning step. There are different methods such as using GPS and conducting survey for volunteer travelers in order to understand actual paths. Obviously, all of these methods have some deficiencies. This research suggests and examines a method for estimating travelers’ path by using cell phone data. The main advantage of using these kinds of data is enabling the process of collecting information without any active interference of the users. A big data set consisting of 300,000 cell phone users’ information in the city of Shiraz is studied to achieve this...
Solving Toll Pricing Problem in Real Transportation Networks
, M.Sc. Thesis Sharif University of Technology ; Zokaee Aashtiani, Hedayat (Supervisor)
Abstract
Toll Pricing as a means to relieve traffic congestion has received significant attention by transportation planners recently. Inappropriate use of transportation networks is one of the major reasons that cause congestion in networks. Toll Pricing is a method of traffic management which guides the traffic flow to proper time and path in order to reduce the total delay in networks. This thesis investigates a method for solving Minimum Toll Revenue problem in real and large scale transportation networks. The objective of this problem is to find tolls that simultaneously cause users to use the transportation network effectively and minimize the total toll revenues that must be collected....
A Mathematical Model for Pricing and Container Repositioning in a Competitive Transportation Network
, M.Sc. Thesis Sharif University of Technology ; Najafi, Mehdi (Supervisor)
Abstract
The transportation is one of the important components in the economies of different countries. In the maritime transportation network, the demand is usually not balanced in different routes, and this imbalance results to accumulation of containers in a node. In order to sustain the problem, firms have to reposition empty equipment from a surplus location to a shortage location, which causes the problem of “Empty Repositioning Problem”. In this study, pricing strategies in one transportation market with two locations are considered; while there is ERP problem in issue. The problem is solved by Bertrand game method. The research is divided into two parts of the monopoly network and the duopoly...
Transportation Problem of Hub Network with Direct Links
, M.Sc. Thesis Sharif University of Technology ; Haji, Rasoul (Supervisor)
Abstract
Hub and Spoke networks come into play when considering direct link between all origins and destinations is either impossible or expensive in a transportation system. In this kind of problems, some nodes are chosen as hub from all origin and destination nodes to collect flows and then distribute them. Implementing hub network leads to minimizing transportation cost, sorting flows and conveying them in economies of scale. Otherwise, shipping flows directly may cause decreasing the travelling distance and the delivery time consequently. In this dissertation, combination of hub network and direct shipment is investigated. To obtain the optimal hub locations and direct links between non-hub nodes...