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Transition from Abelian Sandpile Model to Manna Model
, M.Sc. Thesis Sharif University of Technology ; Moghimi-Araghi, Saman (Supervisor)
Abstract
In this research, we want to address the question of universality classes in BTW and Manna sandpile models. So far, number of works has been devoted to this issue but the the answer remained unsolved. We will try another approach to study this question by perturbing the original models. To this end, we introduce three models that have evolution rules between BTW model and Manna model. By simulating this models, we observe that in the presence of perturbation, the probability dis- tribution has two regimes of behaviour which are separated by a new characteristic scale. The regime of small avalanches is described by the exponent of BTW model and the regime of large avalanches by the exponent...
Developing an Object Oriented Agent Based Platform for Optimizing Gas Transmission Networks
, M.Sc. Thesis Sharif University of Technology ; Bozorgmehri, Ramin (Supervisor)
Abstract
Nowadays, one of the most challenging issues concerning the manufacturing industries is the shortage of available resources and their increased costs. As a matter of the fact, for these industries, optimizing the processes is not something to be ignored and one of the most important goals is reducing the costs of manufacturing and increasing the profits of sales. On the other hand, in actual situations, due to the complexities of optimization problem and numerous calculations, the classical methods would be limited to very simplistic cases in which most of the practical changes are ignored. In such problems, the need to use strong optimization techniques like the genetic algorithm is evident...
Continuous transforming the BTW to the Manna model
, Article Physica A: Statistical Mechanics and its Applications ; Volume 419 , 2015 , Pages 196-202 ; 03784371 (ISSN) ; Moghimi Araghi, S ; Najafi, M. N ; Sharif University of Technology
2015
Abstract
In this paper we define some stochastic perturbations of the BTW model which make it into Manna model. These models have a continuous parameter p, where p = 0 and 1 correspond to the BTW and Manna models respectively. We have investigated the properties of the statistical observables of the waves of avalanches for various values of p. Our data supports the expectation of a crossover in such systems; at large scales Manna model is dominant. Therefore we find strong evidence in favor of the universality classes being distinct. Also it is observed that the BTW fixed point is unstable when Manna-type perturbation is added to the model
Buckling behavior of the anchored steel tanks under horizontal and vertical ground motions using static pushover and incremental dynamic analyses
, Article Thin-Walled Structures ; Volume 112 , 2017 , Pages 173-183 ; 02638231 (ISSN) ; Rahimzadeh Rofooei, F ; Khajeh Ahmad Attari, N ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
This paper investigates the static and dynamic buckling of an anchored cylindrical steel tank subjected to horizontal and vertical ground acceleration. The buckling capacity of the tank is estimated using static pushover (SPO) and incremental dynamic analyses (IDA). Appropriate load patterns due to the horizontal and vertical components of ground excitations are utilized for SPO analyses. The buckling capacity curves and critical buckling loads computed using SPO analyses are compared to those obtained from IDA. A proper vertical to horizontal acceleration ratio (av/ah) for SPO analysis is proposed that leads to good agreement between SPO and IDA results. © 2017
Face Forgery Detection Through Statistical Analysis and Local Correlation Investigation
, M.Sc. Thesis Sharif University of Technology ; Ghaemmaghami, Shahrokh (Supervisor) ; Amini, Sajjad (Supervisor)
Abstract
Existing face forgery detection methods mainly focus on certain features of images, such as features related to image noise, local textures or frequency statistics of images for forgery detection. This makes the extracted representations and the final decision depend on the data in the database and makes it difficult to detect forgery with unknown manipulation methods. Solving this challenge, which is called the generalization challenge in artificial intelligence literature, has become the main goal of researchers in this field. In this thesis, the focus is on extracting effective features for success in forgery detection and preventing the performance of the forgery detection network from...
Seismic Response and Buckling behavior of Aboveground Cylindrical Steel Tanks
, Ph.D. Dissertation Sharif University of Technology ; Rahimzadeh Rofooei, Fayaz (Supervisor) ; Khaje Ahmad Attari, Nader (Co-Advisor)
Abstract
In this study, the seismic response of aboveground, anchored cylindrical steel tanks subjected to horizontal and vertical ground acceleration is investigated. The buckling capacity of the steel tanks is estimated using static pushover (SPO) and incremental dynamic analyses (IDA). Finite element models of a broad tank and a tall tank with height to diameter ratios (H/D) of 0.40, 0.80 and with a liquid level of 90% of the height of the cylinder were used in this study. Appropriate load patterns due to the horizontal and vertical components of ground excitations are utilized for SPO analyses. The influence of the vertical component of ground acceleration on buckling capacity curve of the tank...