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yazdian-hosseinpour--amir
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Investigation of the Effects of Wall Roughness on the Acoustic Field for Flow Inside a Pipe
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor)
Abstract
One of the methods of measuring the flow rate in a pipe (channel) is by using the acoustic waves with long wavelenghs in Sonar flowmeters. This flowmeter consists of an array of sensors, mounted on the outer wall of the pipe. These sensors by listening and interpreting the sound waves passing through the fluid, would give a “non-intrusive” measurement of the volumetric flow rate. This means that the flowmeter is not in direct contact with the flow and therefore its repair, relocation or replacement will not disturb the flow. In this project, we will provide a clear understanding of the principles and physics involved in sonar-based acoustic flowmeters, by means of numerical simulation of the...
Adaptive modulation technique for amplify & forward cooperative diversity and fairness analysis
, Article 2008 International Conference on Telecommunications, ICT, St. Petersburg, 16 June 2008 through 19 June 2008 ; October , 2008 ; 9781424420360 (ISBN) ; Pakravan, M. R ; Sharif University of Technology
2008
Abstract
In recent years, cooperative diversity techniques have gained increased attention as a new method to combat degrading channel effects. Cooperation among two or more single antenna users generates a virtual diverse multiple-antenna transmission system in the wireless network. In this paper, we propose a scheme to improve the spectral efficiency of the Amplify and Forward system and investigate the application of adaptive modulation concept to the performance of cooperative techniques. We consider the adaptation of rate and power allocation with MQAM modulation and study the performance of Amplify & Forward scenarios in Rayleigh fading channels. We compare this system with its comparable...
Adaptive modulation technique for cooperative diversity in wireless fading channels
, Article 2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, Helsinki, 11 September 2006 through 14 September 2006 ; 2006 ; 1424403294 (ISBN); 9781424403295 (ISBN) ; Pakravan, M. R ; Sharif University of Technology
2006
Abstract
In recent years, cooperative diversity techniques have gained increased attention as a new way to combat degrading effects of Fading. Cooperation among two or more single antenna users generates a virtual diverse multiple-antenna transmission system in the wireless network. In this paper, we investigate the application of adaptive modulation concept to the performance of cooperative techniques. We consider the adaptation of rate and power allocation with M-QAM modulation, and study the performance of Amplify & Forward scenarios in Rayleigh fading channels. We compare these systems with their comparable adaptive non-cooperative scenario and evaluate the energy saving achieved through...
Source Enumeration and Identification in Array Processing Systems
, Ph.D. Dissertation Sharif University of Technology ; Bastani, Mohammad Hasan (Supervisor)
Abstract
Employing array of antennas in amny signal processing application has received considerable attention in recent years due to major advances in design and implementation of large dimentional antennas. In many applications we deal with such large dimentional antennas which challenge the traditional signal processing algorithms. Since most of traditional signal processing algorithms assume that the number of samples is much more than the number of array elements while it is not possible to collect so many samples due to hardware and time constraints.
In this thesis we exploit new results in random matrix theory to charachterize and describe the properties of Sample Covariance Matrices...
In this thesis we exploit new results in random matrix theory to charachterize and describe the properties of Sample Covariance Matrices...
Source enumeration in large arrays using moments of eigenvalues and relatively few samples
, Article IET Signal Processing ; Volume 6, Issue 7 , 2012 , Pages 689-696 ; 17519675 (ISSN) ; Gazor, S ; Bastani, H ; Sharif University of Technology
IET
2012
Abstract
This study presents a method based on minimum description length criterion to enumerate the incident waves impinging on a large array using a relatively small number of samples. The proposed scheme exploits the statistical properties of eigenvalues of the sample covariance matrix (SCM) of Gaussian processes. The authors use a number of moments of noise eigenvalues of the SCM in order to separate noise and signal subspaces more accurately. In particular, the authors assume a Marcenko-Pastur probability density function (pdf) for the eigenvalues of SCM associated with the noise subspace. We also use an enhanced noise variance estimator to reduce the bias leakage between the subspaces....
Continuous Synthesis of Medicine Utilizing Catalyst Through a Microreactor System
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Khorasheh, Farhad (Supervisor) ; Hosseinpour, Vahid (Co-Supervisor)
Abstract
Nowadays, the use of microreactors is receiving a great deal of attention due to the unique characteristics of such systems, such as high surface-to-volume ratio, low material loss, greater safety, and minimizing mass and heat transfer limitations. In this study, the optimization of the continuous-flow synthesis of Plavix by Cu-MOF heterogeneous catalyst utilizing a glass microreactor was investigated. Structural characteristics of the catalyst were investigated using X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and BET surface area studies to describe the structure and morphology of the catalyst. In order to build...
Source enumeration in large arrays based on moments of eigenvalues in sample starved conditions
, Article IEEE Workshop on Signal Processing Systems, SiPS: Design and Implementation, 17 October 2012 through 19 October 2012, Quebec ; October , 2012 , Pages 79-84 ; 15206130 (ISSN) ; 9780769548562 (ISBN) ; Bastani, M. H ; Gazor, S ; Sharif University of Technology
2012
Abstract
This paper presents a scheme to enumerate the incident waves impinging on a high dimensional uniform linear array using relatively few samples. The approach is based on Minimum Description Length (MDL) criteria and statistical properties of eigenvalues of the Sample Covariance Matrix (SCM). We assume that several models, with each model representing a certain number of sources, will compete and MDL criterion will select the best model with the minimum model complexity and maximum model decision. Statistics of noise eigenvalue of SCM can be approximated by the distributional properties of the eigenvalues given by Marcenko-Pastur distribution in the signal-free SCM. In this paper we use random...
Spectral distribution of the exponentially windowed sample covariance matrix
, Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, 25 March 2012 through 30 March 2012, Kyoto ; 2012 , Pages 3529-3532 ; 15206149 (ISSN) ; 9781467300469 (ISBN) ; Bastani, M. H ; Gazor, S ; Sharif University of Technology
IEEE
2012
Abstract
In this paper, we investigate the effect of applying an exponential window on the limiting spectral distribution (l.s.d.) of the exponentially windowed sample covariance matrix (SCM) of complex array data. We use recent advances in random matrix theory which describe the distribution of eigenvalues of the doubly correlated Wishart matrices. We derive an explicit expression for the l.s.d. of the noise-only data. Simulations are performed to support our theoretical claims
Limiting spectral distribution of the sample covariance matrix of the windowed array data
, Article Eurasip Journal on Advances in Signal Processing ; Volume 2013, Issue 1 , 2013 ; 16876172 (ISSN) ; Gazor, S ; Bastani, M. H ; Sharif University of Technology
2013
Abstract
In this article, we investigate the limiting spectral distribution of the sample covariance matrix (SCM) of weighted/windowed complex data. We use recent advances in random matrix theory and describe the distribution of eigenvalues of the doubly correlated Wishart matrices. We obtain an approximation for the spectral distribution of the SCM obtained from windowed data. We also determine a condition on the coefficients of the window, under which the fragmentation of the support of noise eigenvalues can be avoided, in the noise-only data case. For the commonly used exponential window, we derive an explicit expression for the l.s.d of the noise-only data. In addition, we present a method to...
Design and Simulation of Simulated Moving Beds
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Fathollah (Supervisor)
Abstract
In this thesis design and simulation of SMB for four different mixture was done with Aspen chromatography package. Simulation for three mixtures of D-Psicose and D-Fructose, racemic mixture of Bupivacaine and Ibuprofen racemate were done with the aim of validation, based on experimental data of articles. The simulation results matched well with the experimental results in articles. The separation of p-xylene from mixed C8 aromatics and Para Diethyl benzene (as desorbent), was simulated for one of the p-xylene producing units and results were validated against the PFD. The influence of various parameters on the purity and recovery of p-xylene were investigated. The studies showed high...
Investigation of heat transfer enhancement in a microchannel heat sink with the aid of internal fins: a metamodel approach
, Article Computer Aided Chemical Engineering ; Volume 48 , 2020 , Pages 85-90 ; Kazemeini, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Heat transfer enhancement with microchannel tools has been increased in recent year. In this study effect of geometric parameters as well as Reynolds number have been studied with experimental design approach. A metamodel was generated in this study for pressure drop and average Nusselt number passed all statistical tests. Order of an individual effect upon a response has been evaluated and interaction effects have been determined. Numerical results indicated that heat transfer increased significantly with inserting pyramidal micro fins. © 2020 Elsevier B.V
Determination of Number and Location of Models to Improve Transient Response in a Multi-model Adaptive Control
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
In recent decays, multiple model controllers have been attracted much attention due to their essential ability to control of non-linear systems with wide operating ranges. Number and location of models are two important factors. In this research an algorithm for determining number of models and their locations has been proposed which can be counted as an extension to existing algorithms. Utilizing the proposed algorithm, the minimum number of models which achieve closed-loop stability can be determined. If transient response of non-linear system with these models be not satisfactory, the number of models are increased by one using Binary Search method, and consequently the location of models...
Development of Hollow Cylinder Apparatus for Testing of Unsaturated Sandy Soils
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
The main purpose of this study is to develop the Hollow Cylinder Apparatus (HCA) for unsaturated testing on granular materials and to investigate the effect of stress anisotropy on dynamic parameters of soils like shear modulus and damping ratio. Direction of loading and the magnitude of intermediate principal stress have significant effect on the anisotropic response of soils. In many of in-situ loading the direction of major principal stress does not coincide with deposition direction of soil or because of the three dimensional loading condition of soil, the effect of the intermediate principal stress cannot be ignored. On the other hand, in many areas, soils are in unsaturated condition....
Visibility Testing of Uncertain Segments
, M.Sc. Thesis Sharif University of Technology ; Ghodsi, Mohammad (Supervisor)
Abstract
Evaluating the enviroment for achieving efcient kwnoledge in order to justifed environment recognition and making decision based on data analysis is proponed in many felds.One of these problems is Visibility Problem. The Recieved data from real world as input, for visibility problem, is uncertain such that the recieving data of two different measurments will be different with high probability. Therefore, we defne the goal of this research to solving the visibility problem conditioned to that objects or segments are uncertain.Consider ”S” as a set of ”n” uncertain segments in plane. Each uncertain segment locates in two certain places and with probability 1 2 in each place, the goal is to...
Chemical-Biological Phosphate Removal Using MBBR Bioreactors
, M.Sc. Thesis Sharif University of Technology ; Borgheei, Mahdi (Supervisor)
Abstract
Growing rate of eutrophication in receiving waters has made the enhancement of wastewater treatment plants to advanced methods of nutrients removal as necessary. Nitrogen and Phosphorus as the nutrients can reduce the quality of water and even make it unusable. Phosphorus is known to be one of the main reasons of eutrophication and creation of algal bloom. In this study, chemical-biological method for phosphate removal from the municipal wastewater is studied. Experiments are implemented for hydraulic retention times of 4, 8 and 16 hours, total intake concentration of phosphorus 7 ppm, COD 400 ppm and Nitrogen 25 ppm. Ferric Chloride as the precipitator chemical substance injected into the...
Enhancing Energy Efficiency in Ideal Binary Distillation tower with a Dynamic Process Intensification
, M.Sc. Thesis Sharif University of Technology ; Vafa, Ehsan (Supervisor)
Abstract
In this thesis titled "Enhancing Energy Efficiency in Ideal Binary Distillation tower with a Dynamic Process Intensification," operational methods in distillation units are explored and improved. Given the high cost of energy, limited energy resources, and environmental considerations, increasing energy efficiency in process industries has become significantly important. In this context, this research attempts to enhance the performance of the distillation unit by utilizing dynamic process intensification with two operational points corresponding to the production of products with purities both higher and lower than the desired product purity, and switching between these two points. The...
Performance improvement of a double stage switch mode AC voltage regulator
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 181-186 ; 9781467301114 (ISBN) ; Karimi, E ; Mokhtari, H ; Yazdian, A ; Sharif University of Technology
2012
Abstract
Widespread use of sensitive loads in industries has required the need for high efficiency voltage regulators in order to provide continuous and fast dynamic adjustable AC voltage. This paper introduces a new control strategy to improve the response time and performance of a double stage switch mode regulator. The proposed strategy responds to input voltage variations quickly and improves the efficiency and performance of the circuit. Results of some simulations are presented and analyzed. Experimental tests on a laboratory prototype verify the excellent performance of the proposed system
Eigenvalue estimation of the exponentially windowed sample covariance matrices
, Article IEEE Transactions on Information Theory ; Volume 62, Issue 7 , 2016 , Pages 4300-4311 ; 00189448 (ISSN) ; Gazor, S ; Bastani, M. H ; Sharifitabar, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, we consider an exponentially windowed sample covariance matrix (EWSCM) and propose an improved estimator for its eigenvalues. We use new advances in random matrix theory, which describe the limiting spectral distribution of the large dimensional doubly correlated Wishart matrices to find the support and distribution of the eigenvalues of the EWSCM. We then employ the complex integration and residue theorem to design an estimator for the eigenvalues, which satisfies the cluster separability condition, assuming that the eigenvalue multiplicities are known. We show that the proposed estimator is consistent in the asymptotic regime and has good performance in finite sample size...
An extended algorithm for autonomous grasping of soft tissues during robotic surgery
, Article International Journal of Medical Robotics and Computer Assisted Surgery ; Volume 16, Issue 5 , 2020 , Pages 1-15 ; Farahmand, F ; Yazdian, S. M ; Mirbagheri, A ; Sharif University of Technology
John Wiley and Sons Ltd
2020
Abstract
Background: Autonomous grasping of soft tissues can facilitate the robotic surgery procedures. The previous attempts for implementing auto-grasping have been based on a simplistic representation of the actual surgery maneuvers. Method: A generalized three-zone grasp model was introduced to consider the effect of the pull force angulation on the grasp mode, that is, damage, slip, or safe grasp. Also, an extended auto-grasping algorithm was proposed in which the trigger force is automatically controlled against the pull force magnitude and direction, to achieve a safe and secure grasp. Results: The autonomous grasping experiments against a varying pull force in a phantom study indicated a good...
An efficient approach to cathode operational parameters optimization for microbial fuel cell using response surface methodology
, Article Journal of Environmental Health Science and Engineering ; Vol. 12, issue. 1 , 2014 ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
2014
Abstract
Background: In the recent study, optimum operational conditions of cathode compartment of microbial fuel cell were determined by using Response Surface Methodology (RSM) with a central composite design to maximize power density and COD removal. Methods: The interactive effects of parameters such as, pH, buffer concentration and ionic strength on power density and COD removal were evaluated in two-chamber microbial batch-mode fuel cell. Results: Power density and COD removal for optimal conditions (pH of 6.75, buffer concentration of 0.177 M and ionic strength of cathode chamber of 4.69 mM) improve by 17 and 5%, respectively, in comparison with normal conditions (pH of 7, buffer concentration...