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mohammad-doost--reza
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Provide a Location-Allocation Model for the Construction of Passenger ports in Mazandaran Province with the using of Robust Optimization Approach and Scenario Building
, M.Sc. Thesis Sharif University of Technology ; Akbari Jokar, Mohammad Reza (Supervisor)
Abstract
Iran has a huge potential in field of tourism and marine passenger transport with possessing 5780 K.M water coast including the island and access to rivers and water basins.Strategic decision of passenger ports construction needs careful location selection andfinding correct trade of point between cost of construction and operation cost. However, according to forecasts increasing cruises demand, creating appropriate port infrastructure to supply thesedemands is a big challenge in next years. Ignoranceof it will prevent the countries development and its communication with other countries.Infrastructure development and creation ofmarine transport modern networks is a pivotal key to satisfy...
Analysis and Optimization of Surge Control System of a Centrifugal Compressor
, M.Sc. Thesis Sharif University of Technology ; Mazaheri, Karim (Supervisor)
Abstract
The surge phenomenon, as the most important aerodynamic instability, has caused a severe drop in efficiency and performance in centrifugal compressors, and its prevention and control is considered one of the main concerns of industrialists. The purpose of this study is to design and develop a surge control system in order to improve the stability and safety of the system under the effect of surge. In this research, after simulating the existing control system and working line in Borzouyeh Petrochemical Industry, by designing and adding the piston surge active control system to the above centrifugal compressor and using the combined control system, the flow rate of the bypass path has been...
Effects of Water Market Formation in the Basin of Lake Urmia
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor)
Abstract
Considering that the agricultural sector is the largest consumer of water in the basin of Lake Urmia, it seems necessary to provide comprehensive methods of water resources management and formulate appropriate policies to increase water productivity in this sector. For this reason, in this research, we examine the effects of creating a water market in the basin of Lake Urmia. For this purpose, models of agricultural economics and positive mathematical programming techniques at the regional level have been used for modeling to analyze the various effects of water market creation. According to the model, the farmer chooses his cultivation pattern according to the price of the crop and the...
A misbehavior‐tolerant multipath routing protocol for wireless Ad hoc networks [electronic resource]
, Article International Journal of Research in Wireless Systems (IJRWS) ; Vol. 2, Issue 9, pp. , Sep. 2013 ; Pakravan, Mohammad Reza ; Aref, Mohammad Reza ; Sharif University of Technology
Abstract
Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network...
Failure Modes Analysis and Mechanisms for Life Extension of Gas Turbines
, M.Sc. Thesis Sharif University of Technology ;
Abstract
Currently, the relatively long time of the turbine life passes and their parts and equipment damage are different, that loss optimum performance and thus reducing their efficiency and may lead to faults and other unexpected stops in their production cycle. Process used to estimate the remaining life of the various components of this turbine is an important tool for improving the efficiency of these units to perform preventive maintenance. In the present thesis, the types of damages in different parts of gas turbines and various methods for detection of critical points, particularly finite element method, high cycle fatigue, modal analysis, methods to estimate the lifetime of a gas turbine...
Seismic performance of precast RC column to steel beam connections with variable joint configurations
, Article Engineering Structures ; Volume 160 , April , 2018 , Pages 408-418 ; 01410296 (ISSN) ; Bakhtiari Doost, R ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In the last decades, noticeable experimental and analytical investigations have been carried out on cast-in-place Reinforced Concrete column to Steel beam (RCS) connections, however rarely have been conducted on the precast RCS. In this paper, test results of four half-scale interior precast RCS connections with variable joint configurations are presented. The steel beams were connected to the precast column, using three specimens with extended face bearing plates and one with extended cover plates, embedded in the connection zone. The flanges of beams were strengthened with respect to scaled section, in order to increase the load transfer to the joint. All samples were loaded under reversed...
Steel web panel influence on seismic behavior of proposed precast RCS connections
, Article Structures ; Volume 32 , 2021 , Pages 87-95 ; 23520124 (ISSN) ; Khaloo, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In this study, the experimental finding of two half-scale interior prefabricated Reinforced Concrete column to Steel beam (RCS) sub-assemblage with proposed joint formations with and without web panel in the junction is presented. Previous researches about RCS have been performed to study shear strength of steel web panel in the joint by modeling joint component, however rarely have been conducted to evaluate joint shear resistance experimentally. Over the past 30 years, noticeable analytical and experimental assessments have been performed on the cast in place RCS joints, but seldom have been done on the prefabricated RCS. The steel beams in the proposed joint are attached to the expanded...
Analysis and Improvement of Intrusion Detection Methods in Data Network Routers
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Pakravan, Mohammad Reza (Co-Advisor)
Abstract
High-quality online services demand reliable and fast packet delivery at the network layer. However, clear evidence documents the existence of compromised routers in the ISP and enterprise networks, threatening network availability and reliability. A compromised router can stealthily drop, modify, inject, or delay packets in the forwarding path to launch Denial-of-Service, surveillance, man-in-the-middle attacks, etc. So researches tried to create intrusion detection methods to identify adversarial routers and switches. To this end, data-plane fault localization (FL) aims to identify faulty links and is an effective means of achieving high network availability. FL protocols use...
Topological Defects in Confined Nematics by Planar Anchoring
, M.Sc. Thesis Sharif University of Technology ; Ejtehadi, Mohammad Reza (Supervisor) ; Mozaffari, Mohammad Reza (Supervisor)
Abstract
Confining nematic liquid crystal between two curved boundary conditions while the nematic molecules have a degenerate planar anchoring leads to complex and beautiful textures of molecular disparagement(defect) in the bulk and on the surfaces. Such the liquid crystal shells are made with double-emulsion techniques in microfluidic devices have provided applications for micro-scale colloidal linkers.In this work, we have numerically minimized the elastic energy in one-constant approximation in present of Fournier’s degenerate surface potential with finite element method. The nematic shell is confined between two spherical surfaces that we have studied the final energies and their related...
Seismic behavior of Moment Resisting Steel Beam-Precast Reinforced Concrete Column Connections
, Ph.D. Dissertation Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
In the last decades, noticeable experimental and analytical investigations have been carried out on cast-in-place Reinforced Concrete column to Steel beam (RCS) connections, however rarely have been conducted on the precast RCS. In this reaserch, test results of five half-scale interior precast RCS connections with variable joint configurations are presented. The steel beams were connected to the precast column, using face bearing plates, embedded in the connection zone. The flanges of beams were strengthened with respect to scaled section, in order to increase the load transfer to the joint. All samples were loaded under reversed displacement controlled condition. The failure mode, joint...
Solving Symmetric Nonlinear Equations System Using BFGS Trust Region Quadratic Method
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor) ; Peyghami, Mohammad Reza (Supervisor)Effect of the Geometry of Colloidal Particles on Nematic Liquid Crystals
, Ph.D. Dissertation Sharif University of Technology ; Ejtehadi, Mohammad Reza (Supervisor) ; Mozaffari, Mohammad Reza (Co-Advisor)
Abstract
A liquid crystal is a state of matter composed of highly anisotropic building blocks. When liquid crystals are exposed to surfaces with given shapes and anchoring conditions, the orientation of their molecules gets spatially disordered and topological defects may form in the system. The interplay between liquid crystals and the geometry and topology of the colloidal particles has motivated extensive recent studies.In this thesis, we present the numerical modeling results for two faceted colloidal particles in a thermotropic nematic liquid crystal. To obtain the equilibrium nematic field with a finiteelement method, we numerically minimize the free energy of the system that based on the...
Design and Implementation of 2.5 Gbps Circuit Switching Fabric
, M.Sc. Thesis Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor) ; Movahhedy, Mohammad Reza (Supervisor)
Abstract
Providing high bandwidth network infrastructures for ever increasing need of data transport is of great importance. The underling infrastructure for many communication services such as GSM/3G/4G mobile networks and Internet services is Synchronous Digital Hierarchy (SDH) optical transport systems. SDH are standardized protocols that multiplex multiple lower rate digital bit streams, such as E1 and Ethernet, and transfer them synchronously over optical fiber using lasers or LEDs. In addition to high data transfer rates, flexible network management and protection mechanisms have great importance, hence are part of SDH standards. In order to obtain flexible network architecture and protected...
Preserving Privacy in Smart Grid
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Pakravan, Mohammad Reza (Co-Advisor)
Abstract
Development of Smart Grid and deployment of smart meters in large scale has raised a lot of concerns regarding customers’ privacy. Consequently, several schemes have been proposed to overcome the above mentioned issue. These schemes mainly rely on data aggregation as a method of protecting users’ privacy from the grid operators. However, the main problem with most of these schemes is the fact that they require a large amount of processing power at the meter side. This, together with the fact that smart meters don’t usually have a powerful processor, can cause the unavailability of smart meter data at the required time for operators of the grid, and at the same time disables smart meters from...
Improvement of Routing Security in Ad Hoc Networks Against Several Attacks
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Pakravan, Mohammad Reza (Supervisor)
Abstract
Secure routing is a major key to service maintenance in wireless ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. Wormhole attack is one of the most severe active attacks to mobile ad hoc networks. Noting the resource limitations in such networks, nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a...
Solving Nonlinear Systems of Mixed Iqualities and Inequalities Via Trust Region Quadratic Methods
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor) ; Payghami, Mohammad Reza (Supervisor)Jamming Resilient Algorithms for Rendezvous in Cognitive Radio Networks
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Pakravan, Mohammad Reza (Co-Advisor)
Abstract
Dynamic spectrum access with the aid of cognitive radio (CR) technology is a viable solution to spectrum scarcity. There are many military and emergency applications that require the use of cognitive radio ad-hoc networks (CRAHNs). In these net- works, nodes must first find each other in a wide spectrum and then exchange their desired data. The process of finding each other in a multichannel environment is a challenging task and is usually known as rendezvous. Since rendezvous is the first step in communication, disrupting will disable the nodes from establishing proper communication sessions. That results in a drastic degrade in the performance of the network. Therefore, it is important to...
Numerical Study of Spray Impingement to Solid Wall
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor) ; Jahannama, Mohammad Reza (Co-Supervisor)
Abstract
Spray-wall impingement is one of the phenomenon that associated in different subject such as spray cooling, combustion chamber and gas turbine. With the impingement of spray to the wall, liquid film begins to form. Wall film characteristics is still an important subject to study. Due to the various stages of liquid film formation from injection of spray till spray-wall impingement, the investigation of this phenomenon is far more complicated. This paper is meant to provide detailed data on spray-wall impingement and wall film formation physics with the help of computational analysis of OpenFOAM . A Lagrangian-Eulerian method based on discrete phase model (DPM) was employed to model...
Analytical Evaluation of Moment Resisting Precast Concrete Beam to Column Connections by Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
In this thesis, the behavior of proposed moment resisting precast beam-column concrete connection under cyclic and monotonic loads is investigated. In this study, the finite element models of precast and monolithic middle and corner connections are created. The results of finite element analysis under cyclic loading is verified with existing experimental results based on failure mode, ductility, energy dissipation capacity and flexural strength. Based on the results of nonlinear finite element analysis, the analytical behavior of samples is in good agreement with experimental results and finite element analysis of proposed precast connection can be replaced with supplementary tests. Then the...
Assessing and Improving Algorithms to Control the Propagation of Light through Scattering Media
, M.Sc. Thesis Sharif University of Technology ; Rahimitabar, Mohammad Reza (Supervisor) ; Nasiriavanaki, Mohammad Reza (Supervisor)
Abstract
Light propagation through turbid media, such as biological tissues, experience scattering due to inhomogeneous distribution of refractive indices of their microscopic structure. Scattering and diffusion of light not only limit many optical imaging techniques, but are also big challenges for telecommunication, spectroscopy, and other optical techniques. Recently many new imaging methods are developed that work in strongly scattering media such as optical coherence tomography, diffusion tomography, and laser speckle velocimetry. In this thesis, we have studied how wavefront shaping techniques can tackle the problem of scattering. By spatially shaping the wavefront of the incident beam, using...