Sharif Digital Repository

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... 

Earthquake is one of the deadliest natural hazards that has taken more than 400 thousand lives, only in the last decade. Iran is one of the countries that are at high risk of potential death toll resulting from such hazards, firstly because it is located in a potentially high-risk zone, the so-called earthquake belt and, secondly because of its problems in the management of disastrous situations (especially, pre-disaster management). Bam 2003 earthquake is one of the most painful experiences in this context. So, in this research, emphasizing on the practical use of optimization models, an existing model is applied on the damaged area of the Bam earthquake. The mentioned model considers the... 

The abstract is the most important section of the thesis because many readers limit most of their reading to abstracts, saving in-depth reading for specific theses. It should give the reader a "preview" of what's to come. The abstract should emphasize new and important aspects of the study or observations. The purpose of the abstract is to allow researchers to decide whether or not to read the whole thesis. The abstract is what researchers read first to decide if the thesis is important, interesting, and it allows them to assess the relevance of a thesis to their own research, without having to read the entire thesis. Thus, it is crucial that the abstract both summarize succinctly the key... 

The purpose of this study is to model the long-term effects of taxes on different aspects of private cars upon auto ownership and use, and thereby auto industries in producing more fit cars, so as to minimize auto emission. It involves used car market, different car demands and auto industry production. The study follows some previous studies in this area and tries to enhance the various aspects of the model by directing it toward a more real situation. In order to visualize the effects of the model, it has been applied on the case of Shiraz in 1378. It has been shown that the model was able to reduce air pollution and fuel consumption by 90% and 50%, respectively, as compared to the “Do... 

This study is part of a bigger project which models Transit-Oriented-Development in deteriorated land use area in order to transfer the residents of the unsafe buildings to new apartments built by the Bus Rapid Transit system, and at the same time increase transit patronage. Residents in the deteriorated land use area (R) trade their land for equivalent value of the new apartment floor area, built by the Private Sector (P). P, in return receive the permission to build equivalent value of “commercial” floor area on the land freed from R. P Builds this new commercial area, Operates it for a life-time (30 to 50 years concession period) and then Transfers it to the City Government, thus a BOT... 

Air pollution is known as one of the most important problems of large cities. The main reason for such air pollution is the increase in using private vehicles. There are some solutions for controlling and reducing air pollution. One efficient way to achieve this goal is by imposing taxes on aspects of private vehicles. The purpose of this study is to investigate the effect of taxes on different aspects of private cars to reduce city air pollution, by (1) promoting users to purchase smaller and higher vehicle technology including electric cars, and drive less, and (2) forcing local car manufacturing companies by market demand mechanism to improve technology in their products. This study is a... 

Throughout history, natural and unnatural disasters have caused great financial and human losses to human beings. Although these incidents are sometimes unpredictable and inevitable, with proper management, the casualties can be reduced. To optimally manage disaster response operations, it is essential to understand people’s vehicular movements in chaotic situations. This can be achieved by examining previous earthquakes. In the post-earthquake conditions, as the network experiences sudden and heavy loading, not only the debris falling on the roads but also the traffic congestion caused by the scared people will cause the links to close, and this will disrupt the relief and rescue... 

Relaxing the underlying assumptions of transportation networks analysis and approaching to more realistic behavioral assumptions in route choice modeling, allows more precise predictions for equilibrium traffic pattern. Furthermore, enhancing the degree of sensitivity in modeling traffic equilibrium is crucial from planning perspective in the sense that it can make transportation analyst capable to evaluate and predict the impacts of a broad spectrum of supply and demand management policies. This research has concentrated on proposing some generalizations in route choice behavior modeling and relaxing some restrictive assumptions of the previous approaches in this area. Formally speaking, in... 

Variations in supply and demand of transportation, as well as those in the related environment, would cause daily variations in user travel time of transportation networks. This phenomenon particularly happen in morning travel time peaks, and make estimation of travel time highly unreliable. Morning peak passengers, whose timely presence at the destinations are highly important to them, prefer to choose paths that have minimum travel time and maximum reliability. Thus, the look at travel time pessimistically, and based on their experience, they put a margin of reliability to reach at timely at their destinations.
This study analysis such reliability margins based on the standard... 

Deteriorated old urban neighborhoods usually have no access to appropriate municipal services, and have small-sized buildings, densely populated areas, and earthquake-prone structures. Residents in these areas do not have the will and financial ability to renovate their aged properties. A questionnaire survey of the citizens living in the deteriorated areas of the City of Tehran showed that 80% of households do not have a positive monthly financial balance and cannot afford the cost of reconstructing their properties. Serious drawbacks of previous attempts to renovate deteriorated areas, including lack of adequate government funding, and adding to the dependence of local citizens on... 

Road network expansion is a well known problem in the world, particularly in developing countries. One approach in financing this development is to charge the users for the services rendered. Recent studies prove the merits of private sector participation in road investment and revenue collection. Public sector may cooprate with private sector in permitting it to build the roads, operate and maintain them for certain period of time, while taking advantage of the revenues collected. The road will, then, be transferred to the public sector when that period of time is over. This study presents an extension to a previous model in this area. It presents a bi-level programming network design... 

Data collected from street networks show that travel time in urban street networks is a stochastic variable, whose range of variation increases with the congestion level. Work and school trips comprise the major part of morning peak volumes, whose common characteristic is that they need to be made on time. For this reason, these travelers are pessimistic in their route choice, and try to choose routes which are more reliable. Travel time standard deviation is one of the common measures for estimating travel time reliability that is related to properties of day-to-day travel time distribution on a particular route. Based on the empirical data collected from Tehran street network, this paper... 

Long-term effects of natural disasters, like earthquakes, in many cases have been reported high on transportation networks. Disruption in this lifeline network's performance imposes high social and economic costs upon the society. Undoubtedly, retrofitting the structures of all network links (or constructing new links) are practically impossible and economically infeasible. One solution to this problem is finding a method for determining the network's important links, and retrofitting their structures. Based on this concept, an optimization problem of network performance improvement under these stochastic events is introduced. In this problem, a link importance index for network links is... 

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.

 

A large number of construction projects include repetitive projects. Many researchers have presented different methods (such as Non-Unit-Based method) for scheduling this class of projects in order to overcome the inabilities of network-based scheduling techniques. Despite the advantages of Non-Unit-Based method over others, it has failed to gain considerable attention. This paper aims to develop this method to enhance its efficiency in scheduling repetitive projects. The first objective of the paper is to develop Non-Unit-Based method in the following aspects :(1) scheduling the project based on the latest start time of crews in addition to the earliest start time of crews;(2) obtaining the... 

Land use and transportation are interrelated, and as a result in cities’ development plans, there is a need for a model that can consider both of them simultaneously. The model presented in this study is bi-level. The upper level designs the zonal population and employment, and transportation network link capacities. Its objective is to minimize the total cost of residence, receiving goods and services, and transportation. The lower level consists of two inter-related problems. One of these problems determines the allocation of population and employment and the other obtains link flows by a joint bi-modal mode choice assignment model. This study aims to develop a meta-heuristic algorithm to...