Sharif Digital Repository

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.... 

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 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.

 

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... 

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.... 

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... 

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.... 

Encouraging passengers in order to use public transportation facilities is one of the goals of transportation planners. The most effective way to increase the market share of public transportation is enhancing its Level of Service via faster and more comfortable transportation in comparison with private vehicles. Exploitation of rapid transportation lines (Subway, BRT, and etc.) is justifiable in corridors in which the demand exceeds a minimum value. While in most of metropolitans such demand may not be present inadvertently in any of corridors, generating the needed demand and increasing the accessibility to public transportation is possible using feeder lines like feeder buses. In fact,... 

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... 

Route information and link traffic volume are among the most important means that are used for analyzing transportation networks. In the past, data from Traffic Counters and Automatic Number Plate Recognition were common ways for estimating route volumes. However, the estimation of these information has improved significantly and can be done cheaper with the development of new technologies and emergence of powerful tools. One of the cheapest and highly available tools is the use of wireless networks. The most popular of such these networks are Bluetooth and Wi-Fi technologies. The use of data generated from these technologies in engineering sciences has increased due to the popularity of... 

The present study investigates dynamic pricing in case of urban transportation operators competing on an identical network. Game theory has been adopted as an approach to the modeling and solutions.Game theory is a mathematical theory widely applied in competitive situations.The proposed model takes the players’ interdependency problems into account to predict their decisions as well as the displacement on the network about equilibrium point. The problem is modeled in no-cooperation state using the dynamic Nash equilibrium; Gauss-Seidel algorithm is used for the solutions considering the discontinuity of the decision space. A comprehensive sensitivity analysis has also been conducted on the... 

Natural disasters, earthquakes in particular, claim many human lives and damage major lifelines such as transportation networks. Transportation networks play an important role in various stages of response to disasters, such as evacuation, search, rescue and reconstruction missions. Hence, special attention must be paid to transportation networks in any disaster management system. Hence, in order to reduce the impacts of earthquakes on denser cities and metropolitan areas, analysis of the resiliency and vulnerability of critical infrastructures such as transportation network, can be used as an effective strategy.The resiliency and vulnerability of transportation network have attract a lot... 

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,... 

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... 

This study aims to solve weekly Flight Frequency Determination and Aircraft Maintenance Routing Problem (AMRP) simultaneously. The objective function here is to maximize the total net profit of an assumptive airline with predetermined airfare and origin-destination market demand. All the needed constraints regarding AMRP is added to the modified version of original model which proposed by Ghafoori in 2011. On the other hand, while this kind of model is based on travelling salesman problem, the occurrence of sub-tours is inevitable. Thus, the model will be, secondly, restricted with more constraints which help eliminate infeasible solutions. The proposed model, then, is tested for three... 

Resiliency is, now, recognized as a vital characteristics of every urban transportation network. This is so, because transportation network is considered as a life-line in disastrous events, such as major earthquakes. In this respect, design of networks may be considered (1) before the incident, (2) after the incident for 72 hours, and (3) from this 72 hours on. From the point of view of (1), design of the network may be considered as strengthening important links under budget constraints to withstand the design incident, in order to be able to function properly (to help the affected people, to evacuate the populated area, etc.).Design of network based on the point of view of (2), the one... 

Natural disasters take many lives each year and leave many others homeless, thereby occupy governments to restore previous conditions rather than deal with progress. Iran has also a worrisome record of natural disasters, and the unpreparedness of the parties involved turn each of such event into a disaster. The purpose of this study is to estimate more accurately the outcomes of severe earthquakes, and show its effect on the decisions which are made to mitigate them. The losses are classified into three groups of immediate, short-run and long-run, which are then measured by some common quantities. Using the 2003 Bam Earthquake as a reference, these quantities are used to measure the... 

Cloud manufacturing (CMfg) as an emerging service–oriented manufacturing paradigm integrates and manages geographically distributed manufacturing resources such that complex and highly customized manufacturing tasks can be performed cooperatively. In this study, a prospective conceptual model for CMfg was developed which can overcome or mitigate the issues and risks associated with supply chain processes on a global scale. Morever, three important problems in CMfg were investigated in this work: 1) Service Composition and Optimal Selection (SCOS), 2) Service Selection Optimization and Scheduling (SSOS), and 3) Sustainable Service Selection and Scheduling (4S). We proposed a new mixed–integer... 

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... 

Due to the importance of hazardous materials (hazmat) transportation, this problem should be programmed and solved appropriately. Hazardous materials are substances that may endanger the health of humans, animals and the environment. One of the most important parameters in hazmat transportation problem is risk, since other routing researches don’t involve risk as an influencing parameter. In the scientific literature of the transport of hazardous materials, the risk is defined by the calculation of the probability and severity of damage to the endangered recipient through unwanted warnings from hazardous substances. In the model of this research, the accident rate is considered as the...