Search for: monte-carlo-simulation
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    Point to point continuum percolation in two dimensions

    , Article Journal of Statistical Mechanics: Theory and Experiment ; Volume 2016, Issue 10 , 2016 ; 17425468 (ISSN) Sadeghnejad, S ; Masihi, M ; Sharif University of Technology
    Institute of Physics Publishing  2016
    The outcome of the classic percolation approach is several power-law curves with some universal (critical) exponents. Here, the universality means that these power laws as well as their critical exponents, which control the global properties of a system, are independent of its details. Classic percolation considers the connectivity between two lines and two faces at opposite sides of a system in 2- and 3D problems, respectively; whereas, in practice (e.g. hydrocarbon formations), production and injection wells are represented by points (in 2D areal models) and lines (in 3D models). This study presents the results of Monte Carlo simulations of a 2D percolation model wherein the connection... 

    A Monte Carlo simulation of nutrient diffusion and reaction in immobilized cell systems

    , Article Chemical Physics ; Volume 321, Issue 1-2 , 2006 , Pages 34-40 ; 03010104 (ISSN) Yari, B ; Khorasheh, F ; Kheirolomoom, A ; Sharif University of Technology
    In this study a Monte Carlo simulation was used to investigate the effect of cell reactivities and particle diffusivities in the cells and matrix on the diffusion and reaction rate constants in gel-immobilized cell systems with different spatial cell configurations. A variety of conditions were examined ranging from instantaneous to very slow reactions with reaction probabilities equal to or less than one, and diffusivity ratios bigger or smaller than one in a spherical domain. In the case of high reactivity (diffusion-limited), the simulation results indicated a decrease in the reaction rate constants when heterogeneity in the cell distribution was increased. In the case of low reactivity... 

    Study Elongation of a Single Strend DNA on the Surface Under Potential Using Monte Carlo Simulation

    , M.Sc. Thesis Sharif University of Technology Kiani, Sedighe (Author) ; Parsafar, Gholamabbas (Supervisor) ; Tafazzoli, Mohsen (Supervisor) ; Ejtehadi, Mohammad Reza (Co-Advisor)
    In this project, the behavior of single strand DNA (ssDNA) that is end-tethred to surface (surface is covered with an layer of mercaptohexane ) through the Monte Carlo simulation has been investigated. To understand this behavior, a ssDNA has been studied through freely jointed chain (FJC) model with electrostatic, base paring, and base-pair stacking interaction. The concentration of sodium chloride salt in solution is 1 mM and the applied surface potential is -1.5 - +0.25 V. Computational results show that the ssDNA chain can have the following configurations: 1) “very closed”, 2) “closed”, and 3) “open” that considering the amount of energy, the mentioned configurations can be compared... 

    Probabilistic analysis of welding residual stress on fatigue crack growth

    , Article Arabian Journal for Science and Engineering ; Volume 34, Issue 1 C , 2009 , Pages 195-205 ; 13198025 (ISSN) Majzoobi, G. H ; Farrahi, G. H ; Fadaee, A ; Sharif University of Technology
    The qualitative effects of residual stress parameters on fatigue crack growth are investigated using Monte Carlo probabilistic analysis technique. These parameters include the maximum residual stress,σ0, half-width of the tensile residual stress region, b, and the redistribution of residual stress parameter, β. A normal distribution is assumed for all parameters considered in the investigation and fatigue life is determined using Forman equation. The results indicate that: (i) fatigue life decreases nonlinearly if the mean of random maximum residual stress and the half-width of tensile residual stress region increases; (ii) fatigue life increases nonlinearly if the rate of residual stress... 

    Composite system well-being analysis using sequential Monte Carlo simulation and fuzzy algorithm

    , Article Istanbul University - Journal of Electrical and Electronics Engineering ; Volume 13, Issue 1 , Dec , 2013 , Pages 1575-1580 ; 13030914 (ISSN) Alinejad, B ; Fotuhi Firuzabad, M ; Parvania, M ; Sharif University of Technology
    Well-Being reliability indices (Health, Margin and Risk), provide a comprehensive measure to assess the adequacy of composite power systems. Conventional reliability information about power system operation only considered health and risk states, which were not often adequate criteria in both power system planning and operation. Well-being approach for power system generation adequacy evaluation incorporates deterministic criteria in a probabilistic framework, and provides system operating information in addition to risk assessment and can be evaluated using analytical techniques. The most important part of this approach is the algorithm for calculating the probability of the states.... 

    Effects of loading modes on reliability of cracked structures using FORM and MCS

    , Article International Journal of Precision Engineering and Manufacturing ; Volume 18, Issue 1 , 2017 , Pages 63-76 ; 22347593 (ISSN) Delbariani Nejad, A ; Nazari, S. A ; Sharif University of Technology
    SpringerOpen  2017
    Studying the reliability of cracked structures under different types of failure modes such as a mixture of Mode I and Mode II loadings has been of great importance in many applications. The purpose of this study is to evaluate the effects of different modes of loading, i.e. pure Mode I, pure Mode II and Mixed mode I/II loadings on the reliability of cracked structures via three typical case studies including 1st: through crack in a very wide plate, 2nd: cracked pressurized fuselage and 3rd: cracked fastener holes under actual geometries and loading conditions using the FORM, the fracture toughness and the equivalent SIF for Mixed mode I/II loading which is extracted by the Energy release... 

    Developing air exchange rate models by evaluating vehicle in-cabin air pollutant exposures in a highway and tunnel setting: case study of Tehran, Iran

    , Article Environmental Science and Pollution Research ; 2018 ; 09441344 (ISSN) Nayeb Yazdi, M ; Arhami, M ; Delavarrafiee, M ; Ketabchy, M ; Sharif University of Technology
    Springer Verlag  2018
    The passengers inside vehicles could be exposed to high levels of air pollutants particularly while driving on highly polluted and congested traffic roadways. In order to study such exposure levels and its relation to the cabin ventilation condition, a monitoring campaign was conducted to measure the levels inside the three most common types of vehicles in Tehran, Iran (a highly air polluted megacity). In this regard, carbon monoxide (CO) and particulate matter (PM) were measured for various ventilation settings, window positions, and vehicle speeds while driving on the Resalat Highway and through the Resalat Tunnel. Results showed on average in-cabin exposure to particle number and PM10 for... 

    Monte Carlo simulation of temperature-programmed desorption CO/Cu(110) and CO2/Cu(100) systems

    , Article Surface Review and Letters ; Volume 11, Issue 2 , 2004 , Pages 137-143 ; 0218625X (ISSN) Zakeri, K. H ; Dashti, A ; Sharif University of Technology
    In this investigation, we have studied the kinetics and mechanism of desorption of CO from the Cu(110) surface using a new Monte Carlo simulation and putting emphasis on high order lateral interaction. According to our simulated TPD spectra, for β 0 = 10 K/s the maximum desorption rate occurs at Tm = 218.6 K. Furthermore, analysis of simulated TPD spectra of CO desorption shows that it is strongly lateral-interactive and results an activation energy of CO desorption from Cu(110) that is Ed = 66.6 Kj/mol. These simulated results are compared with other reported results and show excellent agreement. After that we have investigated the kinetics and mechanism of desorption of CO2 from the... 

    Monte Carlo simulation of 2-ethoxyethanol in continuum configurational biased procedure: Conformational analysis and association in aqueous and non-aqueous media

    , Article Theoretical Chemistry Accounts ; Volume 107, Issue 3 , 2002 , Pages 162-172 ; 1432881X (ISSN) Tafazzoli, M ; Jalili, S ; Sharif University of Technology
    Springer New York  2002
    Monte Carlo simulations have been carried out for 2-ethoxyethanol (C 2E1) in isothermal-isobaric ensemble (NPT) at different temperatures and 1 atm pressure with a continuum configurational biased procedure in water and chloroform media. Hydrogen bond bridges were formed between adjacent oxygen atoms in C2E1 (CH 3CH2OCH2CH2OH) through water molecules. We also found that the stable conformers of C2E 1 in water and CHCl3 are different and the effect of temperature on solute-solvent interaction energies is considerable. The self-association of C2E1 in aqueous and nonaqueous media has been studied by statistical perturbation theory, and the relative free energy has been obtained at different... 

    Study of association of 2-methoxyethanol in the aqueous phase

    , Article Theoretical Chemistry Accounts ; Volume 106, Issue 3 , 2001 , Pages 194-198 ; 1432881X (ISSN) Tafazzoli, M ; Jalili, S ; Sharif University of Technology
    Springer New York  2001
    Monte Carlo simulations have been carried out for 2-methoxyethanol in an isothermal-isobaric ensemble (NPT) at 298.15 K and 1 atm pressure. The optimized potential for liquid simulation force field parameters has been used for modeling 2-methoxyethanol and the TIP4P model for water. Intramolecular rotations are described by an analytical potential function fitted to ab initio energies. It has been shown that the water molecules can form hydrogen bonds between adjacent O atoms of CH3OCH2CH2OH in aqueous media. The self-association of 2-methoxyethanol in aqueous media has been studied by statistical perturbation theory  

    Analyzing Airport Saturation Based on Continuous Descent Approach

    , M.Sc. Thesis Sharif University of Technology Norouzi, Ramin (Author) ; Malaek, Mohamad Bagher (Supervisor)
    Airport saturation is one of the important issues which have always been of the specialists’ concern. One of the major applications of this subject is at the airport approach problems. While using current conventional approach procedures have many disadvantages regarding high fuel consumption and subsequent much environmental and noise pollution, the CDA concept which is one of the modern topics introduced in consequence of free flight theory, has less such disadvantages compared to conventional approach. Subject of this study is to investigate whether Procedural approach or CDA saturates an aiport sooner if the traffic flow increases. In this dissertation, using BADA database, CDA... 

    Uncertainty Quantification of Two Phase Immiscible Water Oil Flow

    , M.Sc. Thesis Sharif University of Technology Mahmoudi, Mehrdad (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    In this project، the immiscible two phase flow of oil-water in the absence of gravity in the two dimensional domain is investigated. The uncertainty quantification of pressure and saturation of fluid in the reservoir are calculated by the methods of statistical moment equation (presented by Tchelepi) and probabilistic collocation method combined with Karhunen Loeve expansion (presented by Heng Lee). Then the results are compared with Monte Carlo simulation. Matlab Reservoir Simulation Toolbox is used for flow simulation. The main problem based on Tchelepi’s work[56[ ، is a horizontal two dimensional problem that there is two injection and production wells at the two end point grids (a... 

    A Dynamic Programming Model to Address Airline Revenue Management

    , M.Sc. Thesis Sharif University of Technology Soleymanifar, Reza (Author) ; Modarres Yazdi, Mohammad (Supervisor)
    In this thesis, we address the Revenue Management problem, when there is cancellation, no-shows, overbooking, and refund constraints. We model this problem using Dynamic Programming. Given the fact that this problem is intractable, we develop a linear programming model that is equivalent to our problem. We first prove that the optimal value of linear programming objective function serves as an upper bound for the Dynamic Program. In the next part we develop a bid-pricing technique, using the shadow prices of the aforementioned linear program, to decide upon rejecting, or accepting the seats, in the network. Using the Monte-Carlo Simulation we show that there is a small distance between the... 

    Structure of DNA Confined in Nano-Environment

    , M.Sc. Thesis Sharif University of Technology Khatami, Maryam (Author) ; Ejtehadi, Mohammad Reza (Supervisor)
    Ejtehadi, M. R. (Mohammad Reza)All cells store their hereditary information in the same linear chemical code, DNA molecule. These information organize all activities of the cell. Therefore, studying various properties of DNA is a big step toward understanding life. Physicists are interested in elastic properties of DNA molecule. DNA is somehow a chain of successive atoms that have been arranged in a helical ladder shape. DNA is a stiff polymer so one has to use a large amount of energy to bend it. Interestingly, in most of the natural cases, DNA is highly packed into spaces that are much smaller that its total length. Cell’s nucleus and viral capsids are some examples. Virus maybe the... 

    ”A Study on the Process of Passive Uptake of Nanoparticles by Coarse-Grained MD Simulation”

    , M.Sc. Thesis Sharif University of Technology Shirzad, Hoda (Author) ; Ejtehadi, Mohammad Reza (Supervisor)
    The aim of this thesis is to investigate the passive wrapping of nanoparticles by a lipid membrane in the uptake process using molecular dynamics computer simulations. The simulations are carried out by the Virtual Cell Model (VCM) software package, a computational framework that creates a large scale coarse-grained multi-component cell model developed by Prof Mohammad Reza Ejtehadi’s Soft Matter Group at Sharif University of Technology. VCM can model the dynamics of different parts of the cell and investigate their mechanical properties.A chapter of this thesis contributes to further development of the membrane model used in the VCM to simulate nanoparticles interactions with a membrane.... 

    Spacecraft Rendezvous and Docking Using Adaptive Neuro-Fuzzy Inference System

    , M.Sc. Thesis Sharif University of Technology Tallebi, Morteza (Author) ; Asadian, Nima (Supervisor)
    In this research an ANFIS controller will be developed to rendezvous and dock with a non-cooperative spacecraft; the controller must make the spacecraft reach the velocity and nearby position of the target spacecraft. Due to uncertainty in modeling and changes in the moment inertia tensor, the controller must be able to adapt with these changes and uncertainty, these changes may happen because of robotic arm or solar panel movings. Robustness of the controller will be evaluated by applying orbital disturbances and modeling errors through monte-carlo simulations. To model the spacecraft the specifications of a known spacecraft will be used but some specifications may be studied parametricaly.... 

    Development of a Systematic Risk-Based Asset Management for Transportation Infrastructure

    , M.Sc. Thesis Sharif University of Technology Tabatabaeipoor, Javad (Author) ; Haj Kazem Kashani, Hamed (Supervisor)
    Asset management involves making decisions related to selecting the most cost-effective asset improvement strategies. There is an increasing interest of risk-based approaches in the field of asset management. During the asset life various risk factors might influence the asset performance and the maintenance cost, therefore, it is important to incorporate these risk factors, which affect the necessity and timing of various activities. This study develops a systemic risk-based asset management methodology (framework) to manage the maintenance of infrastructure assets. This paper presents an overview of uncertainty problems in cost estimating of bridge in the future and also discusses... 

    A low power 1.2 GS/s 4-bit flash ADC in 0.18 μm CMOS

    , Article Proceedings of IEEE East-West Design and Test Symposium, EWDTS 2013 ; 2013 ; 9781479920969 (ISBN) Chahardori, M ; Sharifkhani, M ; Sadughi, S ; Sharif University of Technology
    A low power 4-bit flash ADC is proposed. A new power reduction technique is employed which deactivates the unused blocks in the converter structure in order to reduce the power consumption. A new method for built-in threshold voltage generation together with a new offset calibration method is used to further reduce the power consumption in the converter. Monte-Carlo simulation shows that after calibration both the INL and the DNL are lower than 0.35 LSB. The converter achieves 3.5 effective number of bits (ENOB) at 1.2 GS/s sampling rate after the offset calibration is performed. It consumes 10 mW from a 1.8 V supply, yielding a FoM of 560 fJ/conversion.step in a 0.18 μm standard CMOS... 

    New SNDR enhancement techniques in pipelined ADC

    , Article 2013 21st Iranian Conference on Electrical Engineering ; May , 2013 , Page(s): 1 - 5 ; 9781467356343 (ISBN) Ghadi, M. H ; Safavi, S. M ; Sharifkhani, M ; Sharif University of Technology
    Signal to Noise and Distortion Ratio (SNDR) is widely chosen for dynamic characterization of ADC. For pipelined ADC in which the inner circuits' errors accumulate at the output, analysis of the origins of SNDR and its characterization can be very hard. However, due to a relationship between maximum INL of ADC and the distortion in its output codes, SNDR can be derived as a function of maximum INL value and its position in output codes. Utilizing this relationship, this paper develops two methods for SNDR enhancement that do not cost much power. The 50k sampled Monte-Carlo simulation in the behavioral level indicates 75% increase in the possibility of having SNDR > 60db just by utilizing... 

    Finite-SNR diversity-multiplexing tradeoff in multi-relay channels

    , Article 2013 Iran Workshop on Communication and Information Theory ; 2013 ; 9781467350235 (ISBN) Haddadpour, F ; Gholami, E ; Rastegar, S. H ; Behroozi, H ; Sharif University of Technology
    In this paper, we investigate the diversity-multiplexing tradeoff (DMT) for multi-relay channels in finite-SNR regime. In our analysis, we consider the decode and forward (DF) relaying strategy and a line of sight path from source to destination. First, we determine the outage probability in a multi-relay scenario and obtain its exact analytical expressions. Then, the outage probability of a multi-relay channel with relay selection is calculated and provided as a closed-form expression. Based on these results, we determine the DMT in finite-SNR regime. Finally, using simulation results, we show that our analysis has accurate results which coincides with that of obtained from Monte-Carlo...