Sharif Digital Repository

There are several methods for measuring thin film thickness, however, for the analysis of liquid film motors [1] we need a method which is capable of measuring the thickness using a single image of the film. In this work, we use the colors that appear on thin films, such as soup bubbles, which is a result of light interference to calculate the thickness of the layer  

One of the most elusive problems in quantum mechanics is the transition between classical and quantum physics. This problem can be traced back to the Schrodinger's cat. A key element that lies at the center of this problem is the lack of a clear understanding and characterization of macroscopic quantum states. Our understanding of Macroscopic Quantumness relies on states such as the Greenberger-Horne-Zeilinger(GHZ) or the NOON state. Here we take a first principle approach to this problem. We start from coherence as the key quantity that captures the notion of quantumness and demand the quantumness to be collective and macroscopic. To this end, we introduce macroscopic coherence which is the... 

With confidence in the recorded observations, the RLS method no longer estimates the recorded measurements by sensors, i.e. the displacement and speed of the floors, and only estimates the parameters. In contrast, in the EKF method, in addition to estimating the structure's parameters, a more precise estimation of the observations recorded by the sensors has been done by accepting the noise in the recorded observations. These methods, which are based on the Bayesian updating, investigate the two primary sources of uncertainty in a problem: a) measurement noise or observation noise, and b) process noise, which includes modeling errors. In these methodologies, the unknown system parameters,... 

According to a novel approach of National Petrochemical Company to deployment of quality concepts on petrochemical projects and effort to develop the excellence models & paragons in various fields like managing contractors of petrochemical project and plans, “Project Based Organizations Excellence Model” presented by Project Management Research and Development Center of National Petrochemical Company as a new pattern of performance improvement in this companies. Implementation of this model in organization also required many infrastructures as knowledge and wisdom, managerial concept, dynamic and process vision that appear gradually. The purpose of this thesis is the development and also... 

A356 Aluminium alloy has an abundant application in the aerospace and automobile industries. One of the most important problems of the alloy is in it’s microstructure after solidification with long dendrite grain of Aluminium.It is stated that solidied grains can be refined by electromagnetic vibration and an alternative electric feild applied simultaneously. To make electric field, electric current passed through the specimen. In order to change in microstructure, electromagnetic vibration was used. Then the effect of intensity of electromagnetic field and alternative electric current on microstructure was examined.Grain refining carried out at electric current 80A and magnetic flux of 13,... 

Entanglement is one of the key resources of quantum information science which makes identification of entangled states essential to a wide range of quantum technologies and phenomena.This problem is however both computationally and experimentally challenging.Here we use autoencoder neural networks to find semi-optimal measurements for detection of entangled states. We show that it is possible to find high-performance entanglement detectors with as few as three measurements. Also, with the complete information of the state, we develop a neural network that can identify all two-qubits entangled states almost perfectly.This result paves the way for automatic development of efficient... 

The vortex tube is a simple device that injects compressed gas (air) tangentially into the vortex chamber through one or more injection nozzles. After entering, the flow becomes rotational and an axial cold flow goes towards the cold outlet and a peripheral hot flow goes towards the hot outlet. Besides all the different applications of the vortex tube, the main application of this device is cooling. Here, the goal is to optimize the geometry and physical conditions to improve the performance, which is done by using a commercial software and numerical analysis of a vortex tube to understand the flow physics and optimization. In this research, we use experimental and numerical data for... 

In this thesis a computational method for the design of optimum nozzle contour with consideration for chemical reactions has been presented. This method combines the method of characteristics, CFD and an optimization algorithm to develop a nozzle suitable for a specific operational condition. First using the method of characteristics an isentropic nozzle contour is achieved. then using the FLUENT solver, this initial contour is solved for flow containing finite-rate reactions and boundary layer effects and by iterating this process combined with an optimization algorithm, an optimum nozzle is found. Properties took into consideration in this method, in addition to chemical reaction between... 

Convolutional neural networks (CNNs) are at the heart of several machine learning applications, while they suffer from computational complexity due to their large number of parameters and operations. Recently, all-optical implementation of the CNNs has achieved many attentions, however, the recently proposed optical architectures for CNNs cannot fully utilize the tremendous capabilities of optical processing, due to the required electro-optical conversions in-between successive layers. Therefore, in our first study, we proposed OP-AlexNet which has five convolutional layers and three fully connected layers. Array of 4f optical correlators is considered as the optical convolutional layer,... 

Although Machine Learning (ML) and especially Deep Learning (DL) has shown significant success in solving complex problems, recent studies have shown that ML algorithms are vulnerable to adversarial attacks. So far, ML algorithms have been designed to run in benign environments. However, the increasing use of ML algorithms in security-sensitive applications motivated adversaries to focus on their vulnerabilities. In the adversarial environment, an adversary can interfere in the training and inference processes of ML algorithms. Adversarial examples are one of the most critical vulnerabilities of ML models at the inference time. Adversarial examples are maliciously crafted inputs that cause... 

Increasing in social communication via electronic ways has been made social network analysis of these communications more important each day. One of the most important aspects in social network analysis is community detection in such networks. There are many different ways to extract communities from social graph structure which in some of them the content of communication between actors has been noticed in community extraction algorithm. In this thesis after a short survey over advantages and disadvantages of existing methods for community detection, a new method for extracting communities from social networks has been suggested which in addition to streaming property of data it spot the... 

Quantum Information Processing (QIP) is one of the active areas of research in both theoretical and experimental physics. Any experimental technique that is used for a scalable implementation of QIP must satisfy DiVincenzo’s criteria [17]. Nuclear Magnetic Resonance (NMR) satisfies many of these conditions, but it is not scalable and cannot initialize the qubits to pure state [28]. NMR can be a great platform for studying the fundamentals of QIP. In this project, for a two­qubit system, we prepare pseudo pure states from the initial mixed states by using unitary operations and implement CNOT gates. According to the results of our experiments, we can apply all the gates with high fidelity....