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The Effect of Polarization in Edge detection in Dispersive Medium
, M.Sc. Thesis Sharif University of Technology ; Amjadi, Ahmad (Supervisor)
Abstract
Introduction: Today, backward and forward scattering tomography of dispersive medium is of great interest because of its broad applications, especially in medical imaging, of breast cancer, Distinguishing different tissues of the body from each other is one of the necessities. Increasing the quality of the image by just a few percents has great improvement on the tomography resolution.
Materials and Methods: In this project we made phantom of the tissue and tumor from Intralipid 10% plus Agarose and Indian ink for soft tissue and plastic fibers as tumor having birefringence factor of 0.001.After putting the plastic tumor in soft tissue phantom, the polarized white light and a digital...
Materials and Methods: In this project we made phantom of the tissue and tumor from Intralipid 10% plus Agarose and Indian ink for soft tissue and plastic fibers as tumor having birefringence factor of 0.001.After putting the plastic tumor in soft tissue phantom, the polarized white light and a digital...
Investigation of Rotational Liquid Film and Electric Power Generation under Electric Field
, M.Sc. Thesis Sharif University of Technology ; Amjadi, Ahmad (Supervisor)
Abstract
Investigation of electrohydrodynamic behavior of fluids under electric fields is a challenging and impressive matter in condensed matter physics. In this thesis, inspired from previous works on liquid film motor, a new phenomenon has been observed and its properties has been investigated.Here by making a new device named “Liquid Film Electric Generator” we produced potential difference on the rotating suspended liquid film under electric field. The power conducted by electrodes has been generated on the surfaces of the film. By this method, under electric field of 1000 V/cm, micro-watt electric power can be achieved on a liquid film of diameter of about 1 cm.We explained this phenomenon on...
Security Issues and Challenges in Vehicular Ad hoc Networks (VANET)
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor)
Abstract
Vehicular ad hoc networks (VANETs) are currently attracting the attention of researchers around the world. They offer a wide range of applications improving road safety and driving comfort. Since VANET applications affect safety-of-life, data security in a vehicular system is mandatory. VANET is a special case of Mobile Ad hoc Network (MANET). Routing in VANET is a controversial issue. Furthermore, Security at routing level is so important because if the routing is compromised, other protocol layers on top of the network layer are also compromised. In this thesis, DSDV, DSR and AODV routing protocols are simulated to understand which of these protocols are suitable for VANET. Finding...
Content Based Community Extraction in Social Networks from Stream Data
, M.Sc. Thesis Sharif University of Technology ; Abolhassani, Hassan (Supervisor)
Abstract
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...
Numerical Modeling of Turbine Flow Meter and Improving its Performance Using CFD
, M.Sc. Thesis Sharif University of Technology ; Karimi, Mohammad Sadegh (Supervisor)
Abstract
Studying the performance of flow meters is of great importance in order to improve their quality. In this study, we are looking for an optimal design for a turbine flow meter in which the measurement accuracy, pressure drop and response speed indices are improved. For this purpose, a turbine flow meter with a diameter of 2 inches has been selected and its performance has been numerically modeled using computational fluid dynamics in a steady and transient state. By modeling the steady state, the measurement accuracy and pressure drop indices are obtained, and by modeling the transient state, the response time of the flow meter is obtained. In order to increase the accuracy of numerical...
Numerical Investigation of the Effect of Cooling Layout Manufacturing Tolerances on the Thermal Field of a Nozzle Guide Vane
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan (Supervisor) ; Karimi, Mohammad Sadegh (Supervisor)
Abstract
One way to increase the efficiency and improve the performance of a gas turbine is to increase the inlet gas temperature. On the other hand, the inlet temperature has an allowable operating range, and increasing it beyond the tolerance of the alloys used in turbine blades causes structural defects and significantly reduces the blade life. Therefore, to increase the blade life, various cooling methods such as internal and layer cooling are used. Considering the blade geometry and cooling paths, accuracy in the manufacturing process is doubly important in the production of these blades. The importance of this issue is that if the cooling channels produced are inconsistent with the design...
Structure Formation and Galactic Dynamics in Modified Gravity (MOG)
, Ph.D. Dissertation Sharif University of Technology ; Rahvar, Sohrab (Supervisor) ; Mohammad Movahed, Sadegh (Co-Advisor)
Abstract
The standard model of Cosmology (SM), based on Einstein’s theory of general relativity (GR), is the best model in describing the cosmic-scale observations. In galactic scales, however, galactic dynamics show a discrepancy between the observed luminous mass and the predicted value from the theory. Two approaches are suggested to eliminate this inconsistency: assuming the existence of dark matter within the context of GR, or modifying the theory of gravity in galactic scales, like MOND or MOG. In this thesis, we study the spherical collapse and the formation of shell galaxies in MOG, in comparison with SM. We introduce the action and the field equations of MOG and the equation of motion of a...
The Dependence Structure of Negatively Dependence Measures
, Ph.D. Dissertation Sharif University of Technology ; Alishahi, Kasra (Supervisor) ; Zamani, Mohammad Sadegh (Co-Supervisor)
Abstract
Strongly Rayleigh measures are an important class of negatively dependent (repulsive) probability measures. These measures are defined via a geometric condition, called “real stability”, on their generating polynomials, and have interesting probabilistic properties. On one important property of negatively dependent measures is their rigid dependence structure. In other words, the it is impossible for these measures to have strong overall dependencies. In this thesis, we study two manifestations if this phenomenon: (1) paving property and (2) tail triviality. Informally, the paving property states that it is possible to partition the set of the components of every strongly Rayleigh random...
Predictive Business Process Monitoring Using Machine Learning Algorithms
, M.Sc. Thesis Sharif University of Technology ; Hassannayebi, Erfan (Supervisor)
Abstract
In order to survive in today's business world, which is changing at a very fast pace, organizations can detect deviations even before they occur, quickly and with a high percentage of confidence, by analyzing their processes, in order to prevent disruptions in the processes. by monitoring the information systems that automatically execute business processes, it is possible to ensure the correct implementation of the existing processes. For this purpose, various techniques for monitoring business processes have been presented so that managers have a comprehensive and real view of how implement processes and be able to identify possible deviations in the future and try to fix them because the...
Virtual Advertisement Replacement in Multi-view Soccer Videos
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
In the past few years, virtual advertisement replacement has become one of the most popular methods of advertising. Currently a few companies are applying this novel technique on highly-viewd soccer videos. In the atmosphere of rivalry for achieving a method of cheapest and least needed-equpiment between companies, this thesis is aimed at introducing an all software system based on multi-view soccer videos. The goal is to bring the best possible qualities given the challenges of this particular definition. This thesis provides a system to replace advertisement boards around soccer field which consists of detection, tracking and adjusting the advertisement. In detection the systems aligns the...
Providing Optimization Tools to Design Aeroelastic Blades of Wind Turbines Made of Curved Fibers
, M.Sc. Thesis Sharif University of Technology ; Haddadpour, Hassan (Supervisor)
Abstract
Nowadays Aeroelasticity is one of most important branch of aerospace science. The Aeroelastic analysis and get on aeroelastic safety margin, is one of the major steps that must be taken in flying crafts design. Diverse software have been developed for this purpose. Due to the increasing the demands of use of composite materials in aircraft structures, need to examine the effect of various parameters such as angles and stacking sequence on the aeroelastic instability (flutter and divergence) composite aircraft structures is determined. The analysis of wind turbines as a means of extracting energy from the wind and having a large diameter blades, causing the interference effects of aerodynamic...
A Nonlinear Viscoelastic Plate Equation with P-laplacian Operator
, M.Sc. Thesis Sharif University of Technology ; Hesaraki, Mahmood (Supervisor)
Abstract
This work is concerned with a class of plate equations with memory and p-laplacian operator with simply supported boundary condition, where Ω is a bounded domain
of RN; g > 0 is a memory kernel that decays exponentially and f(u) is a nonlinear perturbation. This kind of problem without the memory term models elastoplastic flows
of RN; g > 0 is a memory kernel that decays exponentially and f(u) is a nonlinear perturbation. This kind of problem without the memory term models elastoplastic flows
Essays In Iranian Wholesale Electricity Market
, Ph.D. Dissertation Sharif University of Technology ; Fatemi Ardestani, Farshad (Supervisor) ; Ghazizadeh, Mohammad Sadegh (Supervisor)
Abstract
In this thesis, consider three important questions in the Iranian Wholesale Electricity Market (IWEM) and answer its. The first one is whether the bidding behavior of the firms in the IWEM has been ex-post optimal? The results of the research show that, on average, the firm’s bidding behavior didn’t optimal in the IWEM, and therefore the bidding strategy of them could be improved. This issue is importance from the regulatory viewpoint in terms of assessing market efficiency and market power of firms, as well as from the firm’s point of view to improve the bidding strategy and increase its profits. The second issue is the assessment of the firm’s ability to exercise unilateral market power by...
Control and Optimization of Office Building Air Conditioning System Taking Into Account Dynamics of Energy Demand, Ambient Indoor and Outdoor Air Quality and Indoor Air Quality Standards
, M.Sc. Thesis Sharif University of Technology ; Khajehpour, Hossein (Supervisor) ; Hassanvand, Mohammad Sadegh (Co-Supervisor)
Abstract
Office buildings, as one of the largest energy consumers in the building sector, play a significant role in national energy consumption. Given the importance of energy optimization in achieving sustainable development, reducing energy consumption in these buildings not only lowers costs but also helps preserve natural resources and mitigate environmental impacts. In this regard, providing energy optimization solutions, improving efficiency, and revising operational patterns play a key role in reducing energy consumption and ensuring user comfort. On the other hand, attention to indoor air quality is equally critical, as polluted indoor air can negatively affect the health and productivity of...
Effecive & efficient DSM configuration guidelines for low-cost development of complex systems
, Article Gain Competitive Advantage by Managing Complexity - Proceedings of the 14th International Dependency and Structure Modelling Conference, DSM 2012, 13 September 2012 through 14 September 2012 ; 2012 , Pages 125-137 ; 9783446433540 (ISBN) ; Sharif University of Technology
Institution of Engineering Designers
2012
Abstract
With the proliferation of more complex systems has come the need to find better solutions in both technical and management domains. Such complex systems are usually larger in size, have more parallel operations and contain more complex interfaces (Eisner, 2005). The Design Structure Matrix is a very useful tool in handling such complexities, provided that the system designer can use it properly. This paper addresses how effectiveness & efficiency are defined for a DSM and how these two important characteristics can be achieved. The importance of understanding the solution space in constructing an effective & efficient DSM is discussed and general guidelines are given on configuring the DSM...
Challenging the effectiveness of information technology strategies in Iran's public sector: A case study
, Article 6th European Conference on e-Government, ECEG 2006, Marburg, 27 April 2006 through 28 April 2006 ; 2006 , Pages 243-252 ; 20491034 (ISSN); 1905305184 (ISBN); 9781905305186 (ISBN) ; Feyzi, A ; Feiz, A ; Sharif University of Technology
2006
Abstract
The Iranian government has started and performed several Information Technology (IT) development plans and projects during recent years with the aim of taking advantage of IT in developing governmental services and increasing their efficiency. This case study intends to investigate the overall effectiveness of the implemented plans according to viewpoints of experts. A survey was conducted in The 1st International Conference on Information and Communication Technology Management in which the attendants were experts from academia and public sector. The questions were designed to obtain their views and standpoints about various issues concerning the success of IT plans in different segments...
Choosing the Optimal Assembly Angle of Multi-Part Elastic Rotor Components with the Aim of Passing Critical Speeds
, M.Sc. Thesis Sharif University of Technology ; Dehghani Firouzabadi, Ruhollah (Supervisor) ; Amirzadegan, Sadegh (Co-Supervisor)
Abstract
Multi-part rotating parts are used in various industries with very high revolutions. Therefore, the method of assembling each part and keeping the axis of rotation of each part close to the axis passing through two supports (bearings) is important. In this research, three main steps are followed, the development of the differential equations governing the multi-part rotating system and the calculation of the range of oscillations created at the critical points, and then the calculation of the optimal assembly angles with the aim of reducing the introduced oscillations, and finally the discussion of crossing the speeds A crisis is being investigated. The method of obtaining the system of...
Investigating Distributed Denial of Service Attacks on MQTT Protocol And Proposal of New Attack Scenarios
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Salmasizadeh, Mahmoud (Co-Supervisor)
Abstract
MQTT (Message Queuing Telemetry Transport) is one of the essential and widely used protocols in the Internet of Things (IoT) networks. It operates at the application layer (Layer 7) for data transmission. As IoT applications using this protocol for communication have grown, securing such systems against security attacks has become a significant challenge. One of the important attacks implementable by IoT networks is Distributed Denial of Service (DDoS) attacks. In this thesis, we initially provide a general overview of IoT security and demonstrate how DDoS attacks disrupt the availability feature in these networks. We then examine known types of DDoS attacks to gain a better understanding of...
Thin Film Thickness Measurement Using Colors of Interference Fringes
, M.Sc. Thesis Sharif University of Technology ; Amjadi, Ahmad (Supervisor)
Abstract
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
Measure for Macroscopic Quantumness via Quantum Coherence and Macroscopic Distinction
, M.Sc. Thesis Sharif University of Technology ; Raeisi, Sadegh (Supervisor)
Abstract
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...