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monte-carlo-methods
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Optimal Sizing and Operation of CHP Based on Stochastic Programming
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
CHP (Combined Heat and Power) generates electricity and thermal energy simultaneously from input fuel. Since it has high energy efficiency and low installation time, it is an appropriate approach in energy management of residential complexes. In this project, stochastic programming based on Monte Carlo approach is used to handle uncertainties in the optimal sizing of CHP for residential complexes. Availability of CHP, boiler and AC bus as well as the electrical and thermal load forecast errors are considered as stochastic variables. Minimizing system total cost considering the probability of each scenario obtained from the scenario reduction algorithm is the objective function. The system...
Developing a 3D DSMC on Unstructured Grid Solver to Simulate Micro/Nanofilters
,
M.Sc. Thesis
Sharif University of Technology
;
Darbandi, Massoud
(Supervisor)
Abstract
Developing new micro and nano devices, help us instruction micro and nano devices in very small scales. Also nano technology improved in recent decades especially in century 21th. These devices contained many important members, such as micro and nano filters, micro channels, sensors, and electrical chipsets. Navier-Stockes equations with slip and no-slip conditions can not used in transition and free molecular regimes. Since most of the MEMS and NEMS devices working in slip and transition regimes, then we must using DSMC for simulation these devices. DSMC is a physically method and working on the physics bases. Also it was derived from Boltzmann equations by Bird. In this study, we want...
Development a Computer Program for Burn-Up Calculation Using Monte-Carlo Method
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor) ; Feghhi, Amir Hossein (Supervisor)
Abstract
Burnup calculations based on the Monte Carlo method have been developed in line with the improvements in computing technology. Nowadays, in the field of nuclear reactor physics, it is possible to perform burnup calculation in a detailed 3D geometry and continuous energy description by the Monte Carlo method. COMB is a fully automated code in DELPHI 7 that links the MCNP4C Monte Carlo transport code with the radioactive decay and burnup calculation code system, ORIGEN2.1. The principal function of COMB is first to transfer one-group cross sections and fluxes from MCNP4C to ORIGEN2.1, and then transfer the resulting material compositions (after irradiation and/or decay) from ORIGEN2.1 back to...
Lifting Body Reentry Vehicle Guidance in Landing using Fuzzy Algorithms
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this thesis, active guidance of a reentry vehicle using fuzzy logic is investigated. The guidance commands of the reentry vehicle (pitch and bank angles) are computed based on estimation of the final conditions, including range and cross-range errors and time-to-go. The final conditions are predicted utilizing a neural network. Inputs of this neural network are the current states of the vehicle and flight time. The first advantage of this approach is that no reference trajectory is required, which is mostly generated optimally for ideal conditions. Moreover, the methods based on keeping the nominal trajectory produce severe guidance commands for sudden disturbances (e.g. wind gusts),...
Simulation of Intensity Modulated Radiation Therapy (IMRT) and Assessment of the Time Parameter
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Mahdavi, Rabi (Supervisor) ; Robat Jazi, Mostafa (Co-Advisor)
Abstract
It is necessary to evaluate dosimetry accuracy in the framework of advanced methods for radiation therapy such as Intensity Modulated Radiation Therapy (IMRT) to ensure reliability of a proposed treatment. The ability of the Monte Carlo codes to model linear accelerator (LINAC) and to calculate the exact dose distribution in clinical radiation therapy is one of the reasons to use such codes. The purpose of this project is to validate a treatment planning system with BEAMnrc and DOSXYZnrc Monte Carlo codes. In this study, the dose distribution obtained from DOSXYZnrc in considered to be thr main criterion with which the dose distribution obtained from treatment planning system is assessed and...
Dose Simulation in Different Body Parts in Radiotherapy Using Fluka Monte Carlo Code on Human Phantom and Benchmarking with TL Dosimetry
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Mahdavi, Rabi (Supervisor)
Abstract
Radiation therapy is a treatment modality that is used in treatment of most newly diagnosed cancer patients. In this method the interaction of radiation with matter and their biological effects is used for cancer treatment. The energy and intensity of the radiation in radiotherapy should be considered in order to have a lethal effect on tumors. Linear accelerators are substitutes for previous methods of radiotherapy in all over the world. These machines can work in both electron and photon mode. The Monte Carlo technique has become ubiquitous in medical physics in the last 50 years. The range of applications is very broad in medical physics. The increased use of Monte Carlo techniques is...
Model for Second Level Domino Effect Analysis in Process Industries
, Ph.D. Dissertation Sharif University of Technology ; Rashtchian, Davoodian (Supervisor)
Abstract
This research is focused on domino accident risk assessment. Domino accidents are such events wherein one accident in a process unit becomes the cause of another (and at times yet another and still other) accident. Domino or knock-on accident is not an infrequent occurrence in process industries. In this research an inventory of the major process industry accidents involving ‘domino effect’ is presented. The inventory includes, among other relevant information, the sequence of accidents that had occurred in each domino episode. The information has been analyzed to identify several patterns which may be useful in further work on understanding domino effect and reducing the probability of its...
A 3-D and Time Dependent Software for Particles Tracking Base on Monte Carlo Method
, Ph.D. Dissertation Sharif University of Technology ; Salehi, Ali Akbar (Supervisor) ; Vosoughi, Naser (Co-Supervisor)
Abstract
A highly reliable tool for transient simulation is vital in the safety analysis of a nuclear reactor. Despite this fact most tools still use diffusion theory and point-kinetics that involve many approximations such as discretization in space, energy, angle and time. However, Monte Carlo method inherently overcomes these restrictions and provides an appropriate foundation to accurately calculate the parameters of a reactor. For this reason, in this thesis, a dynamic Monte Carlo code named MCSP (Monte Carlo dynamic Simulation of Particles tracking) is developed for both the steady state and time-dependent simulation of particle (neutrons, photons and electrons) tracking in an arbitrary 3D...
Evaluating The Effects Of Anatomical Variations In An Equilibrium Finite Element Model Of Lumbar Employing The Monte Carlo Simulation
, M.Sc. Thesis Sharif University of Technology ; Parnianpour, Mohamad (Supervisor) ; Asghari, Mohsen (Supervisor)
Abstract
Spinal Column is one of the most important parts of musculoskeletal system. Injuries in this region are so rampant and causing vast expense. Risk factors related to spine injuries included personal related ones such as, age, sex, muscles’ strength and career related ones such as body positions at work place and loads. Since in vivo measurements have many restrictions, developing biomechanical models that simulate the response of a person to given loads and conditions has important role in preventing injuries and improving working conditions. Inputs to current models of the spine are considered to have mean value, therefore muscles’ forces and other outputs of these models have single value...
Modeling of Optimal Design of Solar Collector in Multi-energy Hybrid Systems based on Minimum Exergy Destruction
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor) ; Fathi, Amir Hossein (Co-Supervisor)
Abstract
Concentrated photovoltaic systems (CPVs) allow simultaneous production of electrical energy and high-temperature thermal energy. These systems consist of a concentrator for collecting solar rays onto the surface of the recipient cells. Moreover, these systems are always facing the sun using a sun tracker. The heat generated by these systems can be used in industrial processes, heating, cooling, and water desalinating. Given the concurrent generation of power and high-temperature heat, it is possible to achieve higher efficiency than that of conventional solar systems. Furthermore, the electrical efficiency is also higher than conventional systems due to the use of multi-junction solar cells...
Mathematical modeling and statistical analysis of second harmonic generation effects with thin and thick crystal in ultrahigh speed optically amplified digital lightwave communication system [electronic resource]
, Article IEEE Journal of Lightwave Technology ; 2009 Vol. 27, No. 16, PP. 3438-3452 ; Salehi, J.A ; Sharif University Of Technology
Abstract
In this paper, we present an in depth analysis and discussions on the behavior and performance of using either thin or thick second harmonic generation (SHG) crystals prior to photodetector in ultrahigh-speed optically amplified digital lightwave communication systems. Our study begins by considering a conventional low-speed optically amplified lightwave receiver and study its performance in ultrahigh-speed regime and show its substantially degraded behavior, indicating the need to use advance optical nonlinear elements such as SHG prior to photodetection. In studying SHG effects, we begin by discussing the mathematical models of thin and thick SHG crystals in the context of statistical...
A comprehensive procedure for characterizing arbitrary azimuthally symmetric photon beams
, Article Physica Medica ; Vol. 30, Issue. 2 , 2014 , Pages 191-201 ; ISSN: 11201797 ; Sohrabpour, M ; Mahdavi, S. R ; Buzurovic, I ; Studenski, M. T ; Sharif University of Technology
Abstract
Purpose: A new Monte Carlo (MC) source model (SM) has been developed for azimuthally symmetric photon beams. Methods: The MC simulation tallied phase space file (PSF) is divided into two categories depending on the relationship of the particle track line to the beam central axis: multiple point source (MPS) and spatial mesh based surface source (SMBSS). To validate this SM, MCNPX2.6 was used to generate two PSFs for a 6MV photon beam from a Varian 2100C/D linear accelerator. Results: PDDs and profiles were calculated using the SM and original PSF for different field sizes from 5×5 to 40×40cm2. Agreement was within 2% of the maximum dose at 100cm SSD and 2.5% of the maximum dose at 200cm SSD...
Prediction of the mechanical properties of rods after cold forging and heat treatment
, Article International Journal of Advanced Manufacturing Technology ; Volume 69, Issue 9-12 , December , 2013 , Pages 2071-2079 ; 02683768 (ISSN) ; Sharif University of Technology
2013
Abstract
A hybrid algorithm based on the finite element method, Monte Carlo model, and Hall-Petch relationship is utilized to predict the mechanical properties of the rods after cold forging at different degrees of deformations and heat treatments at different temperatures and times. The results show that the flow stress and hardness of the rods after forging and those of the forged rods after the heat treatments are decreased from their center to surface. However, with increasing the temperature and time of the heat treatment the flow stress and hardness are decreased, their effects are not considerable. In addition, the distribution of the mechanical properties of the forged rods after the heat...
Extension of particle filters for time-varying target presence through split and raw measurements
, Article IET Radar, Sonar and Navigation ; Volume 7, Issue 5 , 2013 , Pages 517-526 ; 17518784 (ISSN) ; Behnia, F ; Sharif University of Technology
2013
Abstract
Target tracking through particle filter (PF) for time-varying presence of a target is compared for thresholded and nonthresholded measurements, where in both cases a track produces more than one measurement. To that end, thresholded split measurements PF along with non-thresholded measurements, sequential importance resampling PF (SIR PF) and auxiliary variable PF (AV PF) are extended to cope with time-varying target presence. Simulations show superiorities in working through non-thresholded measurements. Furthermore, they surprisingly demonstrate that non-thresholded measurements SIR PF leads to less root-mean-square position estimation error than non-thresholded measurements AV PF in case...
Leak-Gauge: A late-mode variability-aware leakage power estimation framework
, Article Microprocessors and Microsystems ; Volume 37, Issue 8 PARTA , 2013 , Pages 801-810 ; 01419331 (ISSN) ; Momtazpour, M ; Goudarzi, M ; Sharif University of Technology
2013
Abstract
Leakage power has already become the major contributor to the total on-chip power consumption, rendering its estimation a necessary step in the IC design flow. The problem is further exacerbated with the increasing uncertainty in the manufacturing process known as process variability. We develop a method to estimate the variation of leakage power in the presence of both intra-die and inter-die process variability. Various complicating issues of leakage prediction such as spatial correlation of process parameters, the effect of different input states of gates on the leakage, and DIBL and stack effects are taken into account while we model the simultaneous variability of the two most critical...
Enhanced autoionization of water at phospholipid interfaces
, Article Journal of Physical Chemistry C ; Volume 117, Issue 1 , 2013 , Pages 510-514 ; 19327447 (ISSN) ; Partovi Azar, P ; Jadidi, T ; Anvari, M ; Jand, S. P ; Nafari, N ; Tabar, M. R. R ; Maass, P ; Bakker, H. J ; Bonn, M ; Sharif University of Technology
2013
Abstract
The structure and autoionization of water at the water-phospholipid interface are investigated by ab initio molecular dynamics and ab initio Monte Carlo simulations using local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation energy functional. Depending on the lipid headgroup, strongly enhanced ionization is observed, leading to the dissociation of several water molecules into H+ and OH- per lipid. The results can shed light on the phenomena of the high proton conductivity along membranes that has been reported experimentally
Visual tracking using D2-clustering and particle filter
, Article 2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012 ; 2012 , Pages 230-235 ; 9781467356060 (ISBN) ; Jamzad, M ; Sharif University of Technology
2012
Abstract
Since tracking algorithms should be robust with respect to appearance changes, online algorithms has been investigated recently instead of offline ones which has shown an acceptable performance in controlled environments. The most challenging issue in online algorithms is updating of the model causing tracking failure because of introducing small errors in each update and disturbing the appearance model (drift). in this paper, we propose an online generative tracking algorithm in order to overcome the challenges such as occlusion, object shape changes, and illumination variations. In each frame, color distribution of target candidates is obtained and the candidate having the lowest distance...
Toward an equation of state for water inside carbon nanotubes
, Article Journal of Physical Chemistry B ; Volume 116, Issue 16 , April , 2012 , Pages 4943-4951 ; 15206106 (ISSN) ; Parsafar, G. A ; Sharif University of Technology
American Chemical Society
2012
Abstract
Water inside carbon nanotubes as an example of nanoconfined water has gained noticeable attention, in both theoretical and applied aspects. Molecular simulation has played a major role in the studies in this field. Yet, there is a need for systematic study of simulation results and compilation of scientifically reliable predictive relations. Here we present Monte Carlo simulations of water inside carbon nanotubes with different radii. An equation of state which was derived on the basis of the extended Lennard-Jones (12,6,3) as the effective pair potential is chosen for the system of water inside the carbon nanotubes. The equation of state is modified to take the effects of anisotropic...
Detail study on improving micro/nano gas mixer performances in slip and transitional flow regimes
, Article Sensors and Actuators, B: Chemical ; Volume 218 , October , 2015 , Pages 78-88 ; 09254005 (ISSN) ; Sabouri, M ; Sharif University of Technology
Elsevier
2015
Abstract
The mixer geometry has substantial effect on mixing performance of different micro/nanomixers. Despite past numerous studies dedicated to mixing of liquid flow streams, there are less efforts to investigate the geometry effects on gas mixing performances. In this work, we focus on gas-gas mixing through different micro/nanoscale mixers under slip and transitional flow regimes. We use the direct simulation Monte Carlo (DSMC) method to provide accurate and reliable results in such flow regimes. To extend our study, we implement different geometrical parameters in our consideration including the mixer size, the impact angle between two incoming gas streams, and the contraction height located in...
Temporal dynamics of connectivity and epidemic properties of growing networks
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 93, Issue 1 , 2016 ; 15393755 (ISSN) ; Khani Shirkoohi, M ; Sharif University of Technology
American Physical Society
2016
Abstract
Traditional mathematical models of epidemic disease had for decades conventionally considered static structure for contacts. Recently, an upsurge of theoretical inquiry has strived towards rendering the models more realistic by incorporating the temporal aspects of networks of contacts, societal and online, that are of interest in the study of epidemics (and other similar diffusion processes). However, temporal dynamics have predominantly focused on link fluctuations and nodal activities, and less attention has been paid to the growth of the underlying network. Many real networks grow: Online networks are evidently in constant growth, and societal networks can grow due to migration flux and...