Sharif Digital Repository

In this thesis we introduce Tropical Geometry and It’s Application in Arithmetic Geometry  

Loess as a kind of collapsible soils is a well-known Aeolian deposit, which is characterized by some specific Engineering properties including high initial void ratio, relatively low initial density and water content and high percentage of fine-grained particles. Collapsible soils such as loess, sustain large stress under dry condition. However, they experience a high and sudden decrease in their volume by reaching to their critical moisture content. As a result, their natural condition is not suitable for construction works if the possibility of the exposure of the soil to excessive water is present. This research presents the utilization of an innovative method for stabilization and... 

Rigid analytic geometry was developed by John Tate in 1971. Although it seems that a rigid analytic spaces on non-Archimedean field F, is like something called F-analytic manifold; however in general these two are distinct concepts.
In this thesis; we introduce rigid analytic spaces. It begins in chapter one by non-Archimedean fields. In this chapter also contains theorem 1-3-7; which there is no proof for it without usage of methods of this chapter; up to the present. Topics discussed in this chapter are interesting subjects of other applica¬tions of non-Archimedean fields. There is a visualization of the field Q_p; and an appendix includes some definitions and consequences of ordered... 

In this thesis, we propose a new compressed-sensing-based algorithm for unmixing of hyperspectral data, and show that the reconstruction quality could be significantly improved. In addition, we illustrate that by utilizing this approach, we can achieve an approximate estimation of the Point Spread Function (PSF) of the hyperspectral images. In this way, we first assume that the PSF belongs to a specific family of functions, such as Gaussian, then, by sweeping the parameters of the assumed PSF, we obtain the abundance coefficient matrix of the reconstructed image. Now, by choosing the sparsest coefficient matrix as the best one, we estimate the corresponding PSF. Then, we further investigate... 

Sampling and recovery of a signal is one of the crucial issues in communication systems. In conventional methods, proper recovery is achieved by sampling the signal at the Nyquist rate, which is twice the signal bandwidth. There have been attempts on reducing the required sampling rate, all of which end in rates equal to a factor of the signal bandwidth. Assuming the sparse nature of the signal in hand, which is a reasonable assumption in many real world scenarios, the theory of Compressed Sensing suggests a sampling rate much less than the Nyquist rate. Designing suitable sensing matrices and efficient recovery of the signal from its samples are the two major challenges of Compressed... 

Stress Absorbing Membrane Interlayer (SAMI) is a slightly thin layer made of bitumen and aggregate placed between a pavement with limited cracking and overlay in order to avoid reflective cracking in overlay. SAMI’s performance depends on many factors such as pavement layer’s materials and thickness and existing pavement’s condition. Numerical simulations are powerful tools to evaluate SAMI’s performance. Previous studies showed that construction of SAMI does not necessarily reduce reflective cracking. This research investigated the effect of different parameters on SAMI’s performance using numerical simulations. The focus of this study was on the performance of SAMIs used between asphalt... 

Hyperspectral unmixing (HU) is a method used to estimate the fractional abundances corresponding to endmembers in each of the mixed pixels in the hyperspectral remote sensing image. In recent times, deep learning has been recognized as an effective technique for hyperspectral image classification. In this thesis, an end-to-end HU method is proposed based on the convolutional neural network (CNN) and multi-layer perceptron (MLP). which consists of two steps: the first stage extracts features from the input data along with the inverse learning of the spectral library matrix in the hyperspectral image where columns represent the pure spectral of endmembers and The second stage is to estimate... 

Video stabilization is one of the main quality enhance- ment techniques for the data captured by a moving/shaking video recorder. In this work, we focus on video stabilization in smartphones equipped with inertial measurement units (IMU). Specifically, we present a fully differentiable dynamic computational graph to compensate for simple pinhole camera model deficiencies, using the suggested model and estimated angular rotation changes inferred from IMU data, We try to improve and stabilize shaky videos. Further using qualitative and quantitative approaches we show our method’s supremacy against current state of the art stabilization methods. This work accompanied with software and necessary... 

While the action in society is at stake, it seems that, I merely do something in my personal sphere, but its consequences will not remain ultimately in my personal sphere. It goes beyond of my personal realm and obviously affects other persons and their choices. This claim is one of the most central claims of Rousseau’s philosophy of right. But if it is so, or in some more technical sense, it is the case that there is some mutual dependence between individuals in social life, then my sphere of freedom would not be merely mine. Consequently, a new question would be of some central importance: What is permissible for me, meanwhile I am living in state of society? Rousseau concludes in response... 

Kolyvagin’s theorem, stated in the late 1980s, is a very important theorem in the theory of elliptic curves, which, together with Gross-Zagier’s work, results in a special case of the Birch and Swinerton-Dyer conjecture, which relates algebraic and analytic properties of the rational elliptic curves to each other. Although the correctness of this conjecture, in general, is an open problem, Kolyvagin’s idea and the concepts he introduced while proving his theorem are very powerful and can be applied to more general situations. The purpose of writing this dissertation is to collect the equivalent forms of Kolyvagin’s theorem with proofs of the main results. We will also give a brief overview... 

This research investigates what consumers in democratized luxury markets value when purchasing luxury items. Nonetheless, these consumers have a limited budget and can not always buy luxury items, yet they are drawn back to these luxury brands. Thus, we use brand engagement in self-concept (BESC) to explain the relationship between these consumers and luxury brands within democratized luxury markets. A conceptualized model of three luxury value dimensions (experiential, symbolic, and functional) is proposed, and 488 cases were gathered through a phone survey. The data were analyzed using partial least squares structural equation modeling (PLS-SEM). The results show that the most critical... 

The issue of global warming and environmental protection is an issue whose importance becomes clearer every day and requires the cooperation of all stakeholders. One of the key stakeholders are consumers. A significant part of environmental pollution is directly or indirectly related to consumer behavior. Understanding the decision-making process and the influencing factors on consumer behavior will help policymakers and legislative bodies to design more effective programs to modify the consumption pattern. Extensive studies have been done on this subject in various research fields. Two theories of planned behavior and value, belief, and norm have been examined in various researches and in... 

With the explosive growth of social media platforms, influencers have emerged as important factors in driving consumer decisions, prompting much research into their influence on their audiences. This study examines the relationship between social media influencers and consumer behavior by examining which characteristics of social media influencers influence consumer attitudes toward products and their resulting purchase intentions and increase their endorsement effectiveness. Through an extensive review of existing literature, this research identifies key influencer characteristics, including authenticity, attractiveness, communication, social responsibilities, and product match-up, as key... 

The present study provids an experimental investigation on two-pase flow characteristics in microchannels. Experiment were conducted with a mixture of air and water in horizontal circular pyrex channel with 400µm inner diameter. The pressure drop and flow rates of the liquid and gas were measured using new method and images of the flow patterns recorded by high shutter speed camera. The gas and liquid superficial velocity ranges were 0.025-12.5m/s and 0.016-3.6m/s, respectively. The flow pattern map is developed from the observed flow patterns based on phases superficial velocity as wel as We numbers of liquid and gas phases. The flow pattern map is compared with those of larger channels.... 

Nowadays, the use of gas turbines with low capacity have acceptance in large quantity. This type of gas turbines with a capacity of approximately 5-200kW are known as microturbines. This type of turbines due to the existence of limitations on increasing of turbine inlet temperature and compressor pressure ratio has low efficiency compared to the turbine with high capacity. Therefore the use of a recuperator in the cycle is necessary. Optimum design of heat recuperator has important effect on improving of gas turbine cycle efficiency. In this project for optimum design of heat recuperator, the effect of recuperator on gas turbine cycle efficiency is studied. By determining geometric... 

The Study of antecedents and considering the status of Project-Based Organizations (PBOs) in our country such as MSA, Azarab, Sadad Machine, etc indicates that they are facing lots of problems in different aspects. This bad situation is in a way that amendment of part of sections guarantees the continuity of bad performance of these companies and we have to apply Business Process Reengineering and establishing a radical change in these firms. So the present research according to managers and experts opinions, several year observations of the writer and review of the literature of BPR, Project Management (PMBOK) and PBOs; and based on a library research, introduces the processes of PBOs in 3...