Loading...
Search for: shahriari--d
0.134 seconds

    Tribological characterization of electroless Ni-10% P coatings at elevated test temperature under dry conditions

    , Article International Journal of Advanced Manufacturing Technology ; Volume 62, Issue 9-12 , October , 2012 , Pages 1063-1070 ; 02683768 (ISSN) Masoumi, F ; Ghasemi, H. R ; Ziaei, A. A ; Shahriari, D ; Sharif University of Technology
    Springer  2012
    Abstract
    An experimental study of wear characteristics of electroless Ni-10% P coating sliding against hard AISI 52100 steel pin is investigated. Experiments are carried out at room and 550°C temperatures. Heat treatment effects on tribological behavior of this coating are studied. The wear surface and the microstructure of the coatings are analyzed using optical microscopy, scanning electron microscopy, energy dispersion analysis X-ray, and microhardness testing equipment. It is observed that the forming of continuous oxide film on contacting surfaces of pin and disk improves wear resistance and decreases friction coefficient of the Ni-10% P coating. The results indicate that the wear resistance of... 

    Vorticity-Bases Adaptive Mesh Refinement for Upscaling of Highly Heterogeneous Porous Media

    , M.Sc. Thesis Sharif University of Technology Shahriari, Arjang (Author) ; Firoozabadi, Bahar (Supervisor)
    Abstract
    The results of numerical simulation of underground flows are greatly affected not only by the discretization method of flow equations, but also by the way that the geological domain is upscaled. Including the detailed knowledge of heterogeneous permeability distribution is mostly neither feasible nor computationally efficient. So it is important to develop efficient grid generation and upscaling methods to simplify the fine-scale flow model while still including the impact of the heterogeneities as far as possible. Thus regions where parameters of interest have larger values or higher changes require finer grid blocks and regions with lower values or minor changes should have coarser grid... 

    Analytical modeling of a Minimally Invasive Surgery grasper actuated by shape memory alloy wires

    , Article International Conference on Robotics and Mechatronics, ICRoM 2013 ; Feb , 2013 , Pages 147-151 ; 9781467358118 (ISBN) Shahriari, M ; Zabihollah, A ; Sharif University of Technology
    2013
    Abstract
    Minimally Invasive Surgery (MIS) is getting common these days. MIS robots using special tools can perform surgery precisely as humans. This is only possible with dexterous end-effectors and a well-controlled system. Local, lightweight and powerful actuators positioned at end-effectors provide the ability to decrease the degrees of freedom and simplify the design. This paper discusses a grasper design actuated by Shape Memory Alloy (SMA) wires that can be used in MIS robotics. The properties of a commercially available shape memory alloy are explored and analytical formulations for the actuation procedure are developed. The grasper actuated by SMA wires is studied and the procedure of... 

    Consequence Modelling of Ethylene Oxide Reactor of Morvarid Petrochemical Co

    , M.Sc. Thesis Sharif University of Technology Shahriari, Esmaeel (Author) ; Rashtchian, Davood (Supervisor)
    Abstract
    As Ethylene Oxide is a highly toxic, flammable, and hazardous material, the consequences of any malfunction in an Ethylene Oxide reactor may be irreparable. The aim of this thesis is to evaluate the probable consequences of an accident in Morvarid Petrochemical Co.’s Ethylene Oxide Reactor in order to find probable hazardous scenarios. In this project, probable accidents were modelled and evaluated by Phast software in different scenarios, and the outcomes were investigated. In addition, if necessary, a set of solutions were proposed to decrease casualties in hazardous scenarios. The results may be used to change layouts according to Consequence Modelling. Results illustrated that... 

    Constructive Mathematics and Quantum Mechanics

    , M.Sc. Thesis Sharif University of Technology Shahriari, Mohsen (Author) ; Ardeshir, Mohammad (Supervisor)
    Abstract
    In constructive mathematics, one has to construct a mathematical object in order to show that it exists. Consequently, some of classical theorems are not acceptable from a constructive point of view. In particular, the constructive validity of the parts of mathematics that play a role in forming physical theories is of interest. Here, we want to examine the constructive provability of some theorems related to quantum mechanics  

    Control of Three-phase UPS with Nonlinear Load Using Disturbance Observer Considering Transformer Concerns

    , M.Sc. Thesis Sharif University of Technology Shahriari, Zohair (Author) ; Tahami, Farzad (Supervisor)
    Abstract
    Nowadays, non-linear loads comprise an important part of electrical grids. One of the most essential sources of nonlinear loads is switching power supplies, which mainly include power electronic rectifiers. When power outage occurs, Uninterruptible Power Supplies (UPS) must be able to supply these loads. The nonlinearity of the load has a significant effect on the Total Harmonic Distortion (THD) of the output voltage, which may not be easily reduced, especially in three-phase inverters. Furthermore, the presence of isolating transformers in these power supplies limits the control of harmonics and intensifies the nonlinear effects of the system.In this Master Thesis, a disturbance observer is... 

    Gait analysis of a six-legged walking robot using fuzzy reward reinforcement learning

    , Article 13th Iranian Conference on Fuzzy Systems, IFSC 2013 ; August , 2013 , Page(s): 1 - 4 ; ISBN: 9781479912278 Shahriari, M ; Khayyat, A. A ; Sharif University of Technology
    IEEE Computer Society  2013
    Abstract
    Free gait becomes necessary in walking robots when they come to walk over discontinuous terrain or face some difficulties in walking. A basic gait generation strategy is presented here using reinforcement learning and fuzzy reward approach. A six-legged (hexapod) robot is implemented using Q-learning algorithm. The learning ability of walking in a hexapod robot is explored considering only the ability of moving its legs and using a fuzzy rewarding system telling whether and how it is moving forward. Results show that the hexapod robot learns to walk using the presented approach properly  

    Vulnerability take grant (VTG): an efficient approach to analyze network vulnerabilities

    , Article Computers and Security ; Volume 26, Issue 5 , 2007 , Pages 349-360 ; 01674048 (ISSN) Shahriari, H. R ; Jalili, R ; Sharif University of Technology
    2007
    Abstract
    Modeling and analyzing information system vulnerabilities help predict possible attacks to computer networks using vulnerabilities information and the network configuration. In this paper, we propose a comprehensive approach to analyze network vulnerabilities in order to answer the safety problem focusing on vulnerabilities. The approach which is called Vulnerability Take Grant (VTG) is a graph-based model consists of subject/objects as nodes and rights/relations as edges to represent the system protection state. Each node may have properties including single vulnerabilities such as buffer overflow. We use the new concept of vulnerability rewriting rule to specify the requirements and... 

    Using CSP to model and analyze transmission control protocol vulnerabilities within the broadcast network

    , Article Proceedings - 2004 International Networking and Communication Conference, INCC 2004, Lahore, 11 June 2004 through 13 June 2004 ; 2004 , Pages 42-47 ; 0780383257 (ISBN) Shahriari, H. R ; Jalili, R ; Sharif University of Technology
    2004
    Abstract
    Spreading networks and increasing their complexity has complicated the task of security analysis. Accordingly, automatic verification approaches have received more attention recently. In this paper, we modeled a network including a set of hosts (clients and servers) using the process algebra CSP in order to verify the Transmission Control Protocol (TCP) behavior against an active intruder. The model is verified using the FDR tool and as a result, some attack scenarios violating the security are found. The scenarios showes how an intruder can compromise the server trust to its clients. As the model is modular, extendable, and scalable, more complex attack scenarios (combination of simple... 

    Modeling of network security-related behaviours using NVML

    , Article 8th International Multitopic Conference, INMIC 2004, 24 December 2004 through 26 December 2004 ; 2004 , Pages 506-511 ; 0780386809 (ISBN); 9780780386808 (ISBN) Shahriari, H. R ; Jalili, R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2004
    Abstract
    Nowadays, security has become an important issue for organizations especially in e-commerce applications. The spreading of networks and increasing of their complexity has complicated the task of security analysis, therefore automatic approaches have received more attention recently. This paper proposes a model-based approach to analyze the overall security of a network, based on the interaction of hosts within the network. A simple language is introduced far modeling securityrelated behaviours of networks and systems. Using the language, a case study is described and its formal model and security properties are presented. © 2004 IEEE  

    A counterexample to polynomially bounded realizability of basic arithmetic

    , Article Notre Dame Journal of Formal Logic ; Volume 60, Issue 3 , 2019 , Pages 481-489 ; 00294527 (ISSN) Ardeshir, M ; Khaniki, E ; Shahriari, M ; Sharif University of Technology
    Duke University Press  2019
    Abstract
    We give a counterexample to the claim that every provably total function of Basic Arithmetic is a polynomially bounded primitive recursive function. © 2019 by University of Notre Dame  

    A counterexample to polynomially bounded realizability of basic arithmetic

    , Article Notre Dame Journal of Formal Logic ; Volume 60, Issue 3 , 2019 , Pages 481-489 ; 00294527 (ISSN) Ardeshir, M ; Khaniki, E ; Shahriari, M ; Sharif University of Technology
    Duke University Press  2019
    Abstract
    We give a counterexample to the claim that every provably total function of Basic Arithmetic is a polynomially bounded primitive recursive function. © 2019 by University of Notre Dame  

    Simulation of NO Production Process from Endothelial Cells and its Effect on Coronary Artery Flow Field

    , M.Sc. Thesis Sharif University of Technology Shahriari, Amir Hossein (Author) ; Firoozabadi, Bahar (Supervisor)
    Abstract
    Endothelial derived nitric oxide (NO) and its role in regulating the physiological conditions of blood vessels is one of the favorite topics among researchers. The majority of previous studies have focused on nitric oxide transport in blood vessels, less attention has been paid to its vasodilative effects in blood vessels. The main aim of this study is to propose an integrated model to study the effects of endothelial-derived nitric oxide on hemodynamic conditions of blood vessels. Nitric oxide is produced by endothelial cells upon exposure to mechanical forces such as hemodynamic shear stress. The synthesized nitric oxide then diffuses into the neighboring vascular smooth cells, where it... 

    An integrated approach for enhancing the quality of the product by combining robust design and customer requirements

    , Article Quality and Reliability Engineering International ; Vol. 30, Issue. 8 , 2014 , pp. 1285-1292 ; ISSN: 07488017 Shahriari, H ; Haji, M. J ; Eslamipoor, R ; Sharif University of Technology
    2014
    Abstract
    Enhancing the quality of the product has always been one considerable concern of production process management, and this subject gave way to implementing so many methods including robust design. In this paper, robust design utilizes response surface methodology (RSM) considering the mean and variance of the response variable regarding system design, parameter design, and tolerance design. In this paper, customer requirements and robust design are regarded simultaneously to achieve enriched quality. Subsequently, with a non-linear programming, a novel method for integrating RSM and quality function deployment has been proposed to achieve robustness in design. The customer requirements are... 

    γ' Precipitate dissolution during heat treatment of nimonic 115 superalloy

    , Article Materials and Manufacturing Processes ; Volume 24, Issue 5 , 2009 , Pages 559-563 ; 10426914 (ISSN) Shahriari, D ; Sadeghi, M. H ; Akbarzadeh, A ; Sharif University of Technology
    2009
    Abstract
    In precipitation hardenable materials, it is desirable to determine the precipitate dissolution temperature for homogenizing the microstructure by controlling the size and distribution of the precipitates. In this research, differential thermal analysis, dilatometry technique, heat treatments followed by microstructure evaluation were used to determine the -γ' dissolution temperature of Nimonic 115. It is assumed that the variation of enthalpy is governed by the changes in y volume fraction and γ concentration with time and temperature, and any contribution of the coarsening of γ' is neglected. The values obtained for the solvus temperature of γ precipitates by the three methods are all in... 

    Two-Dimensional Dictionary Learning and its Application in Image Denoising

    , M.Sc. Thesis Sharif University of Technology Shahriari Mehr, Firooz (Author) ; Babaiezadeh, Masoud (Supervisor)
    Abstract
    Sparse representation and consequently, dictionary learning have been two of the great importance topics in signal processing problems for the last two decades. In sparse representation, each signal has to be represented as a linear combination of some basic signals, which are called atoms, and their collection is called a dictionary. To put it in other words, if complete dictionaries such as Fourier or Wavelet dictionaries are used for the representation of signals, the representation will be unique, but not sparse. On the other hand, if overcomplete dictionaries are used, we will confront with too many representations, and the goal of sparse representation is to find the sparsest one. ... 

    RT-UNNID: A practical solution to real-time network-based intrusion detection using unsupervised neural networks

    , Article Computers and Security ; Volume 25, Issue 6 , 2006 , Pages 459-468 ; 01674048 (ISSN) Amini, M ; Jalili, R ; Shahriari, H. R ; Sharif University of Technology
    2006
    Abstract
    With the growing rate of network attacks, intelligent methods for detecting new attacks have attracted increasing interest. The RT-UNNID system, introduced in this paper, is one such system, capable of intelligent real-time intrusion detection using unsupervised neural networks. Unsupervised neural nets can improve their analysis of new data over time without retraining. In previous work, we evaluated Adaptive Resonance Theory (ART) and Self-Organizing Map (SOM) neural networks using offline data. In this paper, we present a real-time solution using unsupervised neural nets to detect known and new attacks in network traffic. We evaluated our approach using 27 types of attack, and observed... 

    Discrete formulation for two-dimensional multigroup neutron diffusion equations

    , Article Annals of Nuclear Energy ; Volume 31, Issue 3 , 2004 , Pages 231-253 ; 03064549 (ISSN) Vosoughi, N ; Salehi, A. A ; Shahriari, M ; Sharif University of Technology
    2004
    Abstract
    The objective of this paper is to introduce a new numerical method for neutronic calculation in a reactor core. This method can produce the final finite form of the neutron diffusion equation by classifying the neutronic variables and using two kinds of cell complexes without starting from the conventional differential form of the neutron diffusion equation. The method with linear interpolation produces the same convergence as the linear continuous finite element method. The quadratic interpolation is proven; the convergence order depends on the shape of the dual cell. The maximum convergence order is achieved by choosing the dual cell based on two Gauss' points. The accuracy of the method... 

    Synthesis of Nano Ceramic Powders for Drug Delivery and It’s Release

    , M.Sc. Thesis Sharif University of Technology Shahriari, Rezvan (Author) ; Nemati, Ali (Supervisor) ; Dobakhti, Faramarz (Supervisor)
    Abstract
    In this project, Fe3O4 nanoparticles were synthesized and coated with different polymeric materials for drug delivery application. For this purpose, water dispersible oleic acid(OA)- pluronic block copolymer coated magnetite iron oxide nanoparticles were synthesized that can be loaded with proper doses of cephalexin. Our data indicated that formulation of iron oxide nanoparticles was developed by optimizing the amount of oleic acid required to coat iron oxide nanoparticles and then by optimizing the amount of pluronic required to form an aqueous dispersion of oleic acid coated nanoparticles. Synthesis of magnetite nanoparticles was done by the addition of a strong base (NH4OH) to ferrous... 

    Local Routing in Geometric Networks

    , M.Sc. Thesis Sharif University of Technology Shahriari, Amir Hossein (Author) ; Abam, Mohammad Ali (Supervisor)
    Abstract
    A geometric network is a weighted undirected graph whose vertices are points in the plane and edge weights are equal to the Euclidean distance of its endpoints. Routing is one of the important problems in graph theory and if the underlying graph is a geometric network,it has applications in different fields including transportation, communication networks and robotics. In many applications the graph data is not accessible or finding the optimal path is costly. Therefore local routing is used. In local routing the goal is that at each vertex,the routing must be done only given the neighbours of the current vertex, the origin and the destination of the route. Geometric spanner is a subgraph of...