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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...
An Investigation on the Effects of Cyclic Quench-Rolling on the Mechanical Properties and Formability of a 7000 Series Aluminum Alloy
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor) ; Serajzadeh, Siamak (Supervisor)
Abstract
Nowadays, Thermomechanical processes are used to change the microstructure and create desirable mechanical properties in metals. In this research, with the aim of improving the mechanical properties and formability of 7000 series aluminum alloys, the Cyclic Quench-Rolling (CQR) process was designed and investigated as a new thermomechanical process with solid solution strengthening mechanism. First, for solution heat treatment, the 7075-T6 aluminum sheet was placed in the oven at 460 °C for 5 hours and quenched in water. After making the solid solution, in each cycle of CQR, a rolling step was performed, then intermediate solutioning heat treatment and then quenching was performed. To study...
Developing a Cloud Platform as a Service to Integrate Enterprise Resource Planning (ERP) Systems in a Supply Chain focusing on consolidated material Requirement planning
, M.Sc. Thesis Sharif University of Technology ; Fatahi Valilai, Omid (Supervisor)
Abstract
With the advent of Internet technology and globalization, the use of enterprise resource planning systems, through the Internet, is growing and indicates access to information and communication as part of a global business strategy.. With the extension of Internet penetration, cloud processing has attracted particular attention. According to this process, due to issues such as maintenance costs, reliability, and scalability, much attention has been paid to cloud enterprise resource planning systems. But major attention has been paid to ERP as a software service, and less has been given to providing cloud platform to develop and integrate enterprise resource planning systems in a supply...
Cortical and subcortical substrates of minutes and days-long object value memory in humans
, Article Cerebral Cortex ; Volume 34, Issue 2 , 2024 ; 10473211 (ISSN) ; Sharifi, K ; Ghazizadeh, A ; Sharif University of Technology
Oxford Academi
2024
Abstract
Obtaining valuable objects motivates many of our daily decisions. However, the neural underpinnings of object processing based on human value memory are not yet fully understood. Here, we used whole-brain functional magnetic resonance imaging (fMRI) to examine activations due to value memory as participants passively viewed objects before, minutes after, and 1–70 days following value training. Significant value memory for objects was evident in the behavioral performance, which nevertheless faded over the days following training. Minutes after training, the occipital, ventral temporal, interparietal, and frontal areas showed strong value discrimination. Days after training, activation in the...
High-throughput low-complexity unified multipliers over GF(2m) in dual and triangular bases
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume PP, Issue 99 , 2016 ; 15498328 (ISSN) ; Bayat Sarmadi, S ; Farmani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Multiplication is an essential operation in cryptographic computations. One of the important finite fields for such computations is the binary extension field. High-throughput low-complexity multiplication architectures lead to more efficient cryptosystems. In this paper, a high-throughput low-complexity unified multiplier for triangular and dual bases is presented, and is referred to as basic architecture. This multiplier enjoys slightly simpler and more regular structure due to use of the mentioned bases. Additionally, structurally improved architectures have been proposed, which have smaller time complexity than basic ones. This is achieved by the use of parallel processing method....
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...
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...
Optimization of Vehicle Routing Problem with Self-pickup-delivery and Option Delivery Locations
, Ph.D. Dissertation Sharif University of Technology ; Akbari Jokar, Mohammad Reza (Supervisor)
Abstract
With the increasing tendency of consumers to purchase from online stores and the remarkable growth of this industry in recent years, timely and cost-efficient delivery of goods to the final customer has become one of its major challenges. Accordingly, last-mile delivery has attracted significant attention from both researchers and practitioners. This study addresses a vehicle routing problem that considers customers’ ability to pick up their orders from selected centers and their possible presence at different locations within the planning horizon. This thesis aims to enhance customer satisfaction and reduce distribution costs by employing two innovative vehicle routing approaches. The first...
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...
Leak detection and localization in water distribution networks using conditional deep convolutional generative adversarial networks
, Article Water Research ; Volume 238 , 2023 ; 00431354 (ISSN) ; Komeilian, P ; Wan, X ; Farmani, R ; Sharif University of Technology
Elsevier Ltd
2023
Abstract
This paper explores the use of ‘conditional convolutional generative adversarial networks’ (CDCGAN) for image-based leak detection and localization (LD&L) in water distribution networks (WDNs). The method employs pressure measurements and is based on four pillars: (1) hydraulic model-based generation of leak-free training data by taking into account the demand uncertainty, (2) conversion of hydraulic model input demand-output pressure pairs into images using kriging interpolation, (3) training of a CDCGAN model for image-to-image translation, and (4) using the structural similarity (SSIM) index for LD&L. SSIM, computed over the entire pressure distribution image is used for leak detection,...
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...
Photocatalytic mechanism of action of apatite-coated Ag=AgBr=TiO 2 on phenol and Escherichia coli and Bacillus subtilis bacteria under various conditions
, Article Progress in Reaction Kinetics and Mechanism ; Vol. 1 , Vol.36 (1) , 2011 , pp.38-52 ; Gholami, M. R. (Mohammad Reza) ; Rahimnejad, S. (Sara) ; Pourbaba, R. (Reza) ; Haghighi, S.(Saeed) ; Sharif University Of Technology
2011
Abstract
Multi-component photocatalysts based on apatite-coated Ag/AgBr/TiO(2) were prepared by the deposition method. The effects of various kinds of apatites, with hydroxyl and fluoro substituents, on photocatalytic activity were investigated. The antibacterial processes in the dark, and under visible light, on two types of bacteria indicate that the multi-composites can inhibit the growth of bacteria by two different mechanisms. TEM images and optical microscopic data demonstrate that by attaching the nanosize catalyst to the outer membrane of the cell, the bacteria could not derive nourishment from surrounding media, i.e. this component acts as bacteria-static. The mechanism for deactivation of...
Solvatochromic Probes Absorbance Behavior in Mixtures of 2-Hydroxy ethyl ammonium formate with methanol, ethylene glycol and glycerol
, Article Journal of Solution Chemistry ; Volume 39, Issue 10 , October , 2010 , pp 1509-1519 ; Harifi-Mood, A. R. (Ali Reza) ; Elahifard, M. R. (Mohammad Reza) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
2010
Abstract
Solute-solvent and solvent-solvent interactions were investigated for binary mixtures of an ionic liquid (IL) 2-hydroxy ethylammonium formate as with methanol, ethylene glycol and glycerol. The physicochemical properties of the solvent mixtures at 25 °C, over the whole range of mole fractions, were determined using solvatochromic probes. High normal polarity ( ENT ) in the alcohol-rich region confirms solute-solvent interactions in this medium. Dipolarity/polarizability (π ∗) show a different trend to ENT with a positive deviation from ideal behavior in IL-glycerol mixtures. However, these deviations for other solvent mixtures are insignificant. Contrary to what is observed for ENT and π ∗,...