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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...
Direct/InverseScattering of SH Wave in an Infinite Elastic Media with Micro/ Nano Inhomogeneity by Couple Stress Theory with Micro Inertia
, Ph.D. Dissertation Sharif University of Technology ; Mohammadi Shodja, Hossein (Supervisor) ; Fotouhi, Morteza (Supervisor) ; Hesaraki, Mahmoud (Co-Advisor)
Abstract
Direct/inverse scattering of high frequency SH-waves by a circular micro-/nano-fiberembedded in an infinite elastic isotropic medium is addressed in the framework of couple stresstheory with micro inertia. The inadequacy of classical theory of elasticity in the problems dealingwith propagation of high frequency waves as well as the problems concerning the elastic fields inthe vicinity of micro-/nano-size defects in which the wavelengths and the size of the defects arecomparable to intrinsic length of the material is well-known. These dilemmas can be remedied byemploying the more accurate higher order continuum theories. So, in the context of couple stresstheory with micro inertia, the...
Improvement of Production Prediction in Reservoir Simulation Using Artificial Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeid (Supervisor) ; Badakhshan, Amir (Supervisor)
Abstract
By far, the most expensive part of the production optimization process is the evaluation of the objective function because this requires computationally expensive reservoir simulations to be performed.One way to reduce this high computational cost isby using surrogates or proxies for the reservoir simulator. There are different methods for constructing a surrogate that their aims are mimicking the reservoir behavior with high accuracy and low computational cost. In reservoir engineering surrogate modeling has been used for the problem of well placement optimization,while in the context of production optimization it has not yet been investigated in the literature. Moreover, most of surrogate...
Preparation of Nanobiocomposites Based on Halloysite Nanotubes-Zein and Evaluation of their Performance for Thin Film Microextraction
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
In this work, a biocompatible sorbent based on halloysite nanotubes-zein bionanocomposite for direct-immersion thin film microextraction (DI-TFME) is introduced. Zein as a biodegradable, low cost and accessible polymer was used to prepare a flexible thin film with the possession of different interactions and good adsorption capacity. To improve the mechanical and chemical resistance of the film, halloysite nanotubes were combined with zein to prepare the thin film sorbent. The film was used for TFME of 16 pesticides from different chemical classes, including organochlorines and organophosphates followed by gas chromatography with electron capture detector (GC-ECD). To achieve the maximum...
Design of a Portable Dilution Sampling System for Measuring Fine Particle and Vocs Emissions from Vehicles and Stack in Iran
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
Combustion sources such as diesel vehicles are the most of the particular matter sources in ambient air. Near the tailpipe, exhaust is very hot, condense and have high velocity. This properties cause to need special methods and instrument to collect them. Numerously of combustion sources will emitted the VOCs, IVOCs, and SVOCs. This component mixed with ambient air and changing to particle phase from gas phase. Reaction between nitrogen oxides with sunlight cause to damage ozone layer and tissue in long time. Furthermore, breathe of VOCs gases cause to eye irritation, gastrointestinal effects, Damage to the nervous system, headache, dizziness, fatigue, vibration and loss of organ...
Reliability-Based Seismic Loss Assessment of Eccentrically Braced Frame Buildings
, M.Sc. Thesis Sharif University of Technology ; Dolatshahi, Kiarash (Supervisor)
Abstract
In this research, seismic loss of eccentrically braced frame buildings is assessed by using reliability methods. For this end, first, Bayesian linear regression is utilized to characterize the epistemic uncertainty of the problem in the form of damage models. The input of these models are mechanical and physical properties of the components, and the outputs are damage ratios. In the second step, by using the developed models and the comprehensive library of probabilistic models of Rt, reliability analysis is conducted on 4, 8, and 16 stories building located in San Jose. The limit state function is seismic loss, including repair loss, collapse loss, and demolition loss, and analysis method...
Probabilistic Framework for Seismic Risk Analysis of Industrial Plants of the Oil Infrastructure
, M.Sc. Thesis Sharif University of Technology ; Mahsouli, Mojtaba (Supervisor)
Abstract
This research proposes a probabilistic framework for seismic risk analysis of industrial plants of oil infrastructure using reliability methods. The proposed approach integrates multiple probabilistic models and system reliability to quantify the seismic risk of the process plants. A chain of probabilistic seismic hazard and risk models is utilized for the risk analysis. The Monte Carlo sampling method is used to propagate the significant uncertainty in the hazard event, damage to components and its consequences, and the potential losses incurred by process plant. In each sample of the analysis, hazard models simulate the occurrence, magnitude, and rupture area and location of earthquake...
An Interior Needle Electropolymerized Pyrrole-Based Coating for Headspace Solid-Phase Dynamic Extraction of Chlorophenols
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
Nowadays, the inside needle capillary adsorption trap (INCAT) technique as a solventless sample preparation approach and alternative extraction method derived from SPME is gaining rising attentions. The INCAT and needle-trap devices are inexpensive, robust, reusable, and are applicable for sampling and analyzing suitable organic compounds from many different sample matrices. Compared to the fragile silica-based SPME fiber, the needle device is nearly impossible to break mechanically. In addition, the extraction medium possesses quite a large extraction phase volume and a powerful preconcentration capability. Similar to SPME, needle-like devices are particularly convenient for automation and...
SNR Improvement in A/D Converters Using Iterative Algorithm
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farrokh (Supervisor)
Abstract
Converting analog signal to digital one is one of the most important issues in signal processing which can be done by using analog to digital converter (A/D). In the first part of this thesis, sigma delta converters based on minimum support filter are investigated. Then, we will show that iterative algorithm can be used in order to improve the performance of the overall system significantly. Asynchronous converters can be utilized for the sake of decreasing power in the process of analog to digital converting. In these converters, a few numbers of samples will be taken from the regions which signal has high autocorrelation. In other words, samples in the asynchronous converters have more...
Reliability Assessment of Wind Power Density in Khouzestan Province
, M.Sc. Thesis Sharif University of Technology ; Moghim, Sanaz (Supervisor)
Abstract
This study seeks to evaluate reliability of wind power density over Khouzestan province using WRF simulations. Based on 10 meter wind speed data extracted from eight synoptic stations over Khouzestan province, two different domains were selected in south and south-west of khouzestan as promising regions with strong wind speeds. WRF model were used to simulate atmospheric data during 2016 and over two selected regions with 2 kilometers grid spacing. Simulated data were verified with comparing to in-situ data via three parameters of RMSE, BIAS and correlation. Results indicate that model configuration had acceptable accuracy in simulating wind speed data. In this study, Monte Carlo...
Compressed Sensing in SAR
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farokh (Supervisor)
Abstract
The remote sensing is the knowledge of gaining information about an event without having direct access to it, and synthetic aperture radars (SAR) have gained spectacular attention in this filed due to their wide applications and high efficiency. The performance of SAR, which are classified in the space-borne or space-borne radars is similar to that of pulse radars. The transmitted signals in SAR are generally chirp signals, and the received signal is two-dimensional which is scattered in two dimensions of range and azimuth called as raw data. Due to relative movement between the radar base and the target point, the distance between the radar base and the target point would not be fixed along...
Study on the Performance of Magnetic Nanoparticles in Hyper-thermic Treatment of Cancerous Tumors, by Heating an MRI Apparatus
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Nourani, Mohammad Reza (Supervisor)
Abstract
The aim of this study was to investigate the rate of increase in temperature of a phantom equivalent to body tissue by different groups of magnetic iron nanoparticles in the external magnetic field to kill cancer cells based on the hyperthermia method. To achieve this goal, three groups of dextran magnetic nanoparticles with different properties and reduced iron oxide-graphene oxide magnetic nanoparticles by M-rGO supercritical synthesis method were used. After XRD, FTIR, SEM, FESEM, VSM, TEM characterization tests, these materials were placed in a phantom made of agarose gel and with the same properties, in a magnetic field with fixed characteristics for all groups and during the process of...
Seismic Reliability and Global Sensitivity Analysis of Concrete Gravity Dams
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor) ; Toufigh, Vahab (Supervisor)
Abstract
This research investigated the seismic performance of gravity dam in the reliability and sensitivity analysis framework under earthquake loading. The performance criteria were defined using crest displacement and tensile stress. The uncertainty due to the material properties of the dam was considered for the reliability approach, in addition to the different ground motion intensity levels for parametric analysis. The exceedance probability of the limit-state functions was computed for varying threshold values through Mean-Value Second-Moment, First-Order Reliability Method and improved Latin Hypercube sampling. Approximation methods were applied along with the sampling method for considering...
10-Bit 500-MS/s Pipelined Analog to Digital Converter
, M.Sc. Thesis Sharif University of Technology ; Hajsadeghi, Khosrow (Supervisor)
Abstract
High speed data converters are very often used in telecommunication systems. Since these systems are increasingly used in mobile form reducing the power consumption in these circuits is of great importance. The goal of this project was to design a pipeline 10 bit converter for a sample rate of 500 M sample/s with a power consumption of 50mW for the input level of 1Vp-p and a 1.5V power supply in 0.18μm CMOS technology. To reach these goals a number of low-power techniques are proposed in various levels of abstraction. In system level, the sampling and feedback capacitors, as well as the stage resolution of the ADC is optimized .And to...
To Estimate Private Rate of Return to Education in Different Grades by Using Quantile Regression Approach
, M.Sc. Thesis Sharif University of Technology ; Keshavarz Haddad, GholamReza (Supervisor)
Abstract
Iranian Household Expenditures and Income Survay(IHEIS) in urban area shows that, average of real hourly wage against the schooling years is declining in the right tail of wage distribution between 1390 and 1384(2005 and 2011). A tentative justification for this observation is that the private rate of return to education at upper quantiles and higher years of schooling have been reduced in the mentioned period. Also, It is observed that the real wage inequality between upper and lower deciles in 1390 is less than 1384. This study intend to investigate the changes in wage inequality between different deciles by different levels of education and rates of return to education in the time...
Fatigue Reliability of Tension-Leg Platform Tendon under Random Wave Load
, M.Sc. Thesis Sharif University of Technology ; Tabeshpour, Mohammad Reza (Supervisor)
Abstract
The primary objective of this research is probabilistic quantification of the fatigue life of tension-leg platforms (TLP) using reliability methods. The need for such methods stems from the significant uncertainty in the loads exerted on offshore structures. The scope of this paper is limited to the study of fatigue in TLP tendons. For this purpose, nonlinear force time history response of the TLP tendon under random wave loads is computed and the damage due to fatigue is estimated in accordance with the Palmgren-Miners rule. Assuming a Rayleigh distribution for stress variation and eight different sea states, the ultimate fatigue damage is computed by accumulating the damage over all...
Improvement of Level Crossing Sampling’s Performance in Sample Reconstruction, Data Compression and Sampler Stages
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farokh (Supervisor)
Abstract
Level crossing sampling is a sampling method in which a sample is taken whenever signal crosses predefined and specific levels. In this dissertation, some recommendations are made in order to increase the sampler’s performance in the sampling, data compression, and reconstruction stages.The IMATMirror algorithm is introduced in the sample reconstruction stage. This algorithm is derived from the IMAT reconstruction method. However, additional data processing is done in each iteration, causing the reconstructed signal to satisfy some properties of the Level-Crossing samples.In order to solve the problem of level crossing sampling of extremely bursty signals (ECG signals for example), a sampler...
Use of Data Assimilation Methods for Multiphase Flow in Porous Media
, M.Sc. Thesis Sharif University of Technology ; Rajabi Ghahnavieh, Abbas (Supervisor) ; Bazargan, Hamid (Co-Supervisor)
Abstract
The importance of optimizing the extraction process of available resources increases each day due to the increasing energy consumption and the lack of energy resources. Oil and gas are one of the most important sources of energy. Although existing oil and gas resources are thought to be sufficient to meet the growing energy demand for the next few decades, given the non-renewable nature of these resources and the growing demand for oil and gas, it will become much harder to meet the future energy demand. Many existing oil fields are now in the process of maturing, and the discovery of large new oil fields is rare. As a result, new technologies must be used in the future to meet this demand,...
Estimating Protein-Protein Interaction Network Similarity through Sampling
, M.Sc. Thesis Sharif University of Technology ; Beigy, Hamid (Supervisor)
Abstract
In examining protein-protein interaction networks, we often encounter similar and repetitive schemes. Examination of these designs, which often appear in the form of motifs and similar patterns, reveals important information such as the type of protein linkage and many of the internal similarities between these networks. The ability to recognize these similarities plays an important role in identifying the function of genes, recognizing the relationships between diseases, and making drugs. We know that exact algorithms for examining subgraph isomorphism are np-hard and time-consuming and infeasible in large networks; Therefore, in practice, approximate and heuristic algorithms are used and...
Optimal Enhancement of Community Resilience through Prioritization of Recovery Operations for Interdependent Infrastructures
, M.Sc. Thesis Sharif University of Technology ; Mahsuli, Mojtaba (Supervisor)
Abstract
In this study, community resilience after a disaster is optimally enhanced for interdependent infrastructures through prioritization of recovery operations considering limited resources. Optimal enhancement of community resilience can be performed at two levels: Pre-disaster and Post-disaster. In the pre-disaster level, resilience enhancement is achieved through optimization of long-term decision making that includes optimized allocation of resources to retrofit of buildings. However, in the post-disaster response and recovery period, allocating resources to retrofit or backup systems is infeasible. Therefore, in the post-disaster level considered in this study, resilience enhancement is...