Sharif Digital Repository

Monge’s problem was solved by Brenier in 1990. In general, the problem remained unresolved for a long time. some of its cases were solved by assumptions, but the general case and its analytical solution for the first time by Ian Bernier The French mathematician was introduced. He wrote his famous article Solved this nonlinear problem with technical assumptions. With the help of convex analysis and fundamental theorems in functions with vector values, he proved the existence and unity of this nonlinear problem. Monge’s problem, also known as optimal transport, suggests whether a stable­sized mapping can be done by having two probabilistic spaces and one cost function. (Inverted image of any... 

The Cost/Benefit Analysis (CBA) is considered to be among the chief and most widely used analytical tools in the realm of public policy and particularly environmental and climatic planning. The National Strategic Plan on Climate Change—a.k.a., Intended Nationally Determined Contribution (INDC) of Iran—under the Paris Agreement (PA) accommodates sets of measures to be undertaken in various sectors of the country, including energy and specifically the power generation sub-sector, so as to reduce the emission of greenhouse gases (GHGs). This study begins with a regression analysis of historical data to identify current trends of fossil fuels consumption, wherefrom the emission level of relevant... 

In 1952, Choquet-Bruhat proved the well-posedness of the Cauchy problem for Einstein’s equation, and demonstrated that a given initial data on a Cauchy hypersurface in spacetime propagates forward in time as a solution to the wave equation. It took nearly half a century for mathematicians to build the necessary tools and techniques for proving the stability of the most basic solution of Einstein’s vacuum equations (EVE), namely Minkowski spacetime. In 1993, Christodoulou and Klainerman showed the global nonlinear stability of this solution using the concept of a double null gauge. The Schwarzschild solution, introduced by Karl Schwarzschild in 1916 for spherically symmetric spacetimes as an... 

Limited water resources in Iran have made dams an important part of the country’s infrastructure. As a result of the large number of in-progress and expected dam projects in the country, consideration of sustainability factors during planning, construction and operation phases of dam projects can create significant economical, social and environmental impacts in the long term. To come up with an inclusive sustainable development, new sustainability assessment approaches seek for sustainable development at the entire project’s life-cycle; they are looking for sustainable development at all design, construction, operation, maintenance and even demolition phases. In this research we have... 

Today’s radio transmitters must be able to send information in several standards. One problem involved in these wide band electronic systems lies in its end part, ie power amplifier. To have a broad band width either switching must be made among several power amplifiers with narrow band width (tuned) or the transistor part of power amplifier must be the same and single and selection be made only among matching networks. In this thesis, a power amplifier with broad band width without requiring a matching network has been designed and laid out. Also considering the low breakdown voltage of the gate oxide of the today’s standard CMOS transistors, it is very difficult to get a high output power... 

In this thesis, we introduce and prove the inequalities and theorems of Smulian which are about derivatives of convex functions and optimization of linear functionals. Then we show that some old ideas of Smulian can be used to give another proof of theorems of Bourgain. The first theorem of Bourgain associates to any bounded, convex, closed and dentable subset like D of a Banach space X a G-delta subset of the dual space and the second theorem of Bourgain investigates the optimization in Banach spaces. Finally, we characterize subsets of Banach spaces having the Radon-Nikodym property by means of optimization results.
 

In this study, hot extrusion of AA2017-10%SiC¬p composite during deformation process and effect of deformation parameters on mechanical properties have been investigated. At the first step, hot compression tests have been carried out to obtain the flow behavior of the material at different temperatures and strain rates. The activation energy of hot deformation was calculated 296 Kj/mol. In the next step, by using a finite element model in ABAQUS software and the results of uniaxial hot compression test behavior of AA2017 and AA2017-10%SiC¬p during hot and warm extrusion have been investigated. By using it temperature gradient and velocity field and strain distribution were predicted. In the... 

Metallurgical initial defects, stress concentration due to change in geometry and induced tensile residual stress during welding create an extraordinary high possibility of fatigue cracks nucleation and propagation in the weld toe region. Despite this, the ever increasing use of welding in offshore, aerospace and automotive industries, as the most applied mechanical joint, has occasioned a very extensive attempt to achieve an in-depth understanding of failure mechanisms and fatigue life improvement techniques of welded joints. Generally, these techniques could be classified into two broad categories. The first consists of methods that modify the geometry and the other is related to the... 

The adaptive nature of agile processes and their conformance to the turbulent nature of business and organizational environments has been greeted with enthusiasm by both project and stakeholder communities. Through deviating from conventional linear and plan-driven frameworks, Agility aims at accommodating the dynamicity of its target environment at the process level during the project lifecycle. This deviation from standard frameworks confronts process management and project framework activities with key challenges. While existing frameworks and standards provide adequate support for linear process management, the agile approach lacks a coherent framework that defines and outlines process... 

Optimum railroad alignment, which can be categorized into continuous problems, has been a conundrum for engineers because of two reasons: At the first, there is a wide variety of information that is necessary for finding optimum one. Secondly, the major costs of a railway, such as length-dependent, traffic-dependent, volume-dependent and location-dependent are affected by the numerous factors so that, it may be difficult to formulate them. In order to solve large scale continuous optimization problems, there are two approaches: firstly, such problems may be tackled with a combinatorial optimization algorithm, e.g. ant colony optimization (ACO), by the continuous range of allowed values are... 

Entrance of secular science to Muslim societies has made them face a duality. That is because, on the one hand, they like to preserve their religious values; and on the other, prevalence of secular ideas prevents people from being committed to such values. Therefore, some Islamic scholars proposed religious science as opposed to Western secular science as a remedy to this crisis In case of religious science, explanatory model has the highest position, but disagreement over how to combine experimental and religious characteristics has led to different models in this area. One of the explanatory models of religious knowledge is that of Doctor Mehdi Golshani which has received due attention at... 

Consumers Communicate with each other to share information and feelings about products and brands. One important area to study personal influence in contemporary environment is online personal influence or electronic word of mouth. This study develops and tests consumers' motivations to participate in eWoM communication in online discussion forums. The main reason to choose Online forums is the huge number of eWoM discussions which occur in them. The main goal of this study is developing an aggregate framework for consumers' motives for opinion giving and seeking in online forums.To accomplish this goal we studied a comprehensive literature review, identified all motivations for WoM and... 

This study strives to solve the course scheduling problem based on the constraints in Sharif University. In course scheduling problem, first we need to assign each course to a professor (This is done according to professors’ preferences in Sharif University) then we assign each course to a classroom and a time slot subject to professors, classrooms and time constraints (For example no two courses can be assigned to the same classroom at the same time slot). If solved manually, the solving process will take several days and at best results in a feasible solution. The education department is responsible for scheduling 661courses in five days a week and assigning them to 56 classrooms... 

Regarding the existing contrary in the literature in relation to the effect of plastic fine on sand liquefaction behaviour, we decided to study this effect. Amounts of 5, 15, and 25 percent of two types of plastic fine, Kaolinite with PI=19 and Bentonite with PI=116 added to Firoozkooh Sand and 68 stress controlled tests were conducted using cyclic simple shear apparatus. In all teste the frequency of shear loading and consolidating vertical effective stress were constant and 0.1 Ht and 100 kPa respectively. Reaching excess pore water pressure ratio to the maximum value (r_u=Max) and reaching double amplitude shear strain to the value of 5% have been considered as liquefaction critera. In... 

Inrush current as an inherent phenomena in transformer energizing cause to dramatic increase in current which flow through windings of transformer in first periods of energizing. first peak of inrush current can exceed even to several orders of nominal current but it decrease with time and at last after damping process it reaches to nominal currents. In large transformer this time can exceed to several minutes and cause damage to winding insulation, mechanical defects, wrong response of protection system and interrupting loads. Magnitude of this current has a close relation with residual flux. In this thesis a method for calculation of inrush current in single phase and three phase... 

Project Scheduling is one of the most important branches of operations research and management science. In this paper, project scheduling problem with a deterministic duration of activities is studied. Resources are considered nonrenewable ones which are perishable. First of all, the project scheduling problem has been studied with a rate of corruption of inventory. Then, a rate of corruption with three parameters for Weibull is considered. Cost function for purchasing a renewable Perishable resource, has been assumed that has growing discounts for the purchase of certain health differently. Project costs are included purchase costs and maintenance costs. The objective function is the... 

In this thesis, we model and analyze coherent optical OFDM systems which are highly concerned as future fiber optic communication. To this end, we first introduce various applications of that in optical communication systems and investigate its probes and cones. In the rest of the thesis, we characterize the mathematical structure of the nonlinear phase noise and discuss the previous methods of compensation of that and propose some new ways of nonlinear phase noise compensation and equalization. And as we discuss each method we also investigate its computational complexity and BER performance. We propose three new phase noise compensation method, considering optical phase conjugation, we... 

Tailings dams are considered as one of the most important geotechnical structures and due to the large amount of contaminated tailings deposited behind the dam, any failure of these structures, apart from loss of lives and properties, can be an environmental disaster. Researches show that most of the failure incidents in the last few decades have happened in tailings dams constructed using upstream method. As a result, it is of great significance to study the stability of upstream tailings dams.
The place of the phreatic line in the dam body plays a critical role in stability of tailings dams. Soil-atmosphere interaction effects such as precipitation, runoff, interception, infiltration,...