Sharif Digital Repository

Multicommodity network flow problem arises in the areas of transportation, logistics, and, telecommunication. The cost of each arc might be a linear or nonlinear function of the sum of commodity flows on that arc. Most of researches have worked on linear multicommodity flow problem. In addition, they consider the shared capacity constraints as the side constraints. In this thesis, we present a penalty-based algorithm for solving the multicommodity network flow problem with a linear or nonlinear objective function and considering the shared capacity constraints as the side. To solve multicommodity network flow problem, we relax the shared capacity constraints, and add a penalty term for the... 

Astransportation networksbecome larger and more congested, designers are seeking more precise, efficient and general algorithms that could use large memoryand powerfulCPUs efficiently. In thisthesis we evaluate Bar-Gera and Dial’sorigin-based algorithms thatsolvethe traffic assignment problem based on the user-equilibrium principal and compare them withthe path-based complementarity algorithm which has been improved in this study. Dial’s algorithm has been implemented in C++ programming language but for Bar-Gera’s algorithm we have usedan executable code that was implemented by him.Networks that have been used in this study are a small hypothetical network, Sioux Falls network, generated... 

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.... 

Nonstop growth of environmental concerns regarding ordinary vehicles detrimental effects have led to increasing use of Electrical Vehicles which require more researches in different fields of study. The main purpose of this study is solving the problem of Electrical Vehicles' traffic assignment considering recharging time as a function of amount of charge. Existing EVs have limited driving range, and these cars' drivers usually have to spend a considerable amount of time on recharging in order to complete a path. As a result, their corresponding optimum route choice differs from that of gasoline-based vehicles' drivers. In more detail, this study proposes an algorithm to solve the shortest... 

Shipment of hazardous materials has got an important role in the world of today. Nowadays, sustainable development has got serious attention, and human health and environment are one of the sustainable development bases. The risk of hazardous materials for human health and environment, and also importance of this kind of materials in the industrial economy, make necessity of programming for shipment of hazardous materials more serious. This thesis, presents an optimiziation model for routing and scheduling for shipment of hazardous materials. This model is a multi criteria time varing mixed integer programming (MIP). The presented model, finds the optimal routs and scheduling of movement... 

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.... 

Wardrop’s first principle for defining the equilibrium flow in transportation networks is one of the mostly accepted assumptions in traffic assignment models. Optimization Models, Variational Inequalities, and Complementarity Equations are among the known models based on this assumption. In these models with the assumption of unlimited capacity for the network’s arcs and use of nonlinear cost functions, the constraint of arc capacity is considered implicitly. Another approach is to consider the arc capacity, explicitly. In recent decade this approach was the subject of some researches. In this thesis, these researches will be discussed. Then, researches about explicit consideration of the... 

Discrete network design problem is selecting a set of feasible projects among a set of candidate projects, considering a budget constraint in which user's cost is being minimized. Network design problem is one of the complicated problems in transportation science, since it is a bi-level problem in which the lower level is a traffic assignment problem and the upper level is finding the best set of arcs. Meta-heuristic algorithms can be used to solve this problem. Although, there is no guarantee to find the optimal solution by Meta-heuristic algorithms, but they find good solutions in short times. The purpose of this study is comparing the efficiency of three Meta-heuristic algorithms for... 

In recent years, traffic assignment problem with side constraints has been considered because of the importance of transportation supply management. Side constraints which are appeared due to imposing the traffic control policies are usually represented in form of link, node or district capacity constraints. Although link capacity constraint has been extensively studied, only a few papers on the other types of constraints such as capacity constraint on inflow to a district of city exist in the literature. In this research a method based on dynamic penalty function (DPF) is presented to solve traffic assignment problem with side constraints. Solution algorithm has been coded in a programming... 

In the transportation litreture, many different algorithms have been proposed for solving traffic assignment problem based on the user-equilibrium principal.These algorithms are devided into two main groups: Path-based algorithms and arc-based algorithms. In the past, arc-based algorithms has attracted quite attention, but recent scientific progress in the computer science changed this viewpoint to the state of path-based algorithms. Much of the attention has been focused on three particular algorithms: the complementarity (C) algorithm, the gradient projection (GP) algorithm and the disaggregate simplicial decomposition (DSD) algorithm. In this thesis, these three algorithms have been... 

Improving synchronization in a bus network has a profound effect on reducung waiting times and increasing satisfaction of system’s users. By doing so, the scheduler create a more attractive transit system that generates the opportunity for increasing the number of riders. In this research, the problem of creating timetables with maximum synchronization is modeled as a mixed integer programing (MIP) problem. The objective of this model is to minimize the total waiting times of passengers at transfer nodes. For this purpose, the model take advantage of uneven headways. Some of features that distinguish this research are more realistic objective function, and considering adjacent departures... 

In this dissertation, transportation networks with two classes of vehicles, including conventional vehicles and autonomous vehicles, have been studied. Four problems, including traffic assignment problem with two classes, congestion pricing problem for conventional vehicles, network design problem for autonomous vehicles, and simultaneous congestion pricing and network design problem, have been modeled and algorithms to solve them are presented. In this study, a dynamic penalty function algorithm is used to solve the congestion pricing problem, and a heuristic algorithm is used to solve the network design problem. Besides, the two-class traffic assignment problem is solved using the... 

In a discrete network design problem (DNDP), an optimal set of projects is chosen from suggested projects to expand a transportation network. The optimal set is selected by minimizing the total travel time with respect to the budget constraint. This problem is formulated as a bi-level optimization. In the current study, traffic assignment is solved at the lower level as a user equilibrium problem by considering the delay of intersections which is the major portion of total intra-city travel time. This study investigates the performance of the transportation network with more realistic assumptions compared to the previous studies in the network design problem.This study uses the branch and... 

In recent decades, widespread application of Linear Complementarity Problems in various branches of science has led to many algorithms which have been proposed to solve these problems in the area of mathematics, economics and computer simulation. Ashtiani used Lemke algorithm for the first time to solve Linear Complementarity Problems in his algorithm for solving Traffic Assignment problem. In this study, Projection Gauss-Seidel algorithm along with two other similar algorithms have been studied for solving Linear Complementarity Problems in Ashtiani Complementarity algorithm and the results are compared with Lemke algorithm. Also an analytical method has been proposed for solving specific... 

Control and managing of fuel consumption is one of the most important issues facing man kind today. Locating gas stations has a great effect on fuel consumption. The gas station locating problem consists of selecting the optimal choice between the candidate nodes for constructing gas stations in such a way that minimizes the excess travel time that results from the gas station not being located on daily travel paths. The gas station locating model is presented for two conditions of either considering and not considering the gas station capacity. In the case of not considering the gas station capacity, a compact model is presented, too. Softwares for medium sized networks and the Simulated... 

Signal Coordination is one of the appropriate methods for delay reduction in intersections. Static Traffic Assignment is unable to reflect the impacts of Signal Coordination in a network. One proper way to overcome this difficulty is to use Dynamic Traffic Assignment (DTA) that can model complex properties of traffic flow. This thesis presents a method to apply Signal Coordination in Cell Transmission Model. Neguin network is tested for different intersection's green start times. The results show that Signal Coordination has great influence on total travel time and route choice in this network. Finally, the results have been checked with AIMSUN NG, a microsimulator software.

 

The trip demand information in the form of the origin-destination (OD) matrix is of significant importance in the transportation studies. Obtaining such a matrix by conventional methods requires a considerable amount of time, cost, and human resources. Traffic count and cellphone network data are two relatively inexpensive data that can be used for estimation of OD matrices as well as correction of prior matrices. The trip demand estimation problem is a bi-level model, and the gradient algorithm is one way to solve it. This study, by generalizing the gradient algorithm, attempts to a better use of the available data. In this algorithm, a complementary algorithm is used to solve the traffic... 

The goal of this research is to solve the traffic assignment of electric vehicles with considering trip chains. Limited driving range of electric vehicles is considered as one the most important obstacles for the development of these cars. The worry that the battery will run out of power before the destination is an important issue regarding the electric cars and people usually experience it more in trip chains. In this research, a complementary model and a linearization method is used for traffic assignment. In determining shortest paths in the traffic assignment, in addition to considering the travel time and the distance limit, the constraint of passing through activity nodes is... 

During the past decade the ever increasing volume of greenhouse gases due to fossil fuels consumption have made humans to seek for alternative, non-polluting fuels as an effective strategy to reduce pollution and prevent environmental issues thereof. Electric cars are today known as one of the most effective solutions for this purpose. Of course, transition from gasoline-powered cars to electric cars in a wide scale is not technically possible in short term due to technological and infrastructural limitations. As a result, this lengthy process would lead to emergence of a combinational transportation system including both gas and electric-powered vehicles. The major differences between these... 

Nowadays, with the advent of Autonomous Vehicles(AV), Researchers in different areas focused more on this type of vehicle. Research shows that autonomous vehicles are faster and more precise than Human-driven vehicles(HDV). So if all the users in a road use autonomous Vehicles, the road’s capacity increases; this Thesis develops a mathematical approach for designing AV exclusive lanes for a time horizon in which there are two types of AVs and HDVs on the road. Considering each type of vehicle’s relative performance for an OD pair in the given year, the demand for that OD pair for the next year calculates with a diffusion model. Designing AV exclusive lanes problem is formulated in a bi-level...