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    Investigating the Use of Gold Nanoparticle in Increasing Dose of Tumor and Reducing the Dose of Normal Tissue in Brachytherapy

    , M.Sc. Thesis Sharif University of Technology Mahmoodi, Monireh (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    Over the past few decades, brachytherapy has been used as one of the leading methods in the treatment of a wide range of cancers, including breast cancer. Due to the high dose gradient of brachytherapy radiation sources, this method is used to treat such tumors that are grown at the vicinity of sensitive points or tissues of the body. Therefore, as irradiation get started by implanting radiation sources in the desired position, at the same time healthy tissue are also receiving the same dose as tumor tissues do Reducing healthy tissue dose along with increasing the dose of tumor tissue is one of the challenging topics that researchers are always looking for a solution. In the left breast... 

    Simulation and Optimization of Dual-Layer Detector Computed Tomography (DLCT) based on the Monte Carlo Method in Order to Reduce the Dose

    , M.Sc. Thesis Sharif University of Technology Shahrokhi, Elham (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    The increasing advancement of computed tomography (CT) systems has led to the recognition of this type of imaging as an accurate and reliable method in diagnosing and assessing damage to humans and materials. Adding dual energy imaging to these systems can increase the material's ability to differentiate in this system and provide higher contrast than usual. Recently, a medical imaging technique has been introduced that uses an X-ray tube and two detector layers on top of each other, each layer absorbing a different energy spectrum.dual layer computed tomography system has been introduced today as a suitable tool for evaluating and diagnosing many diseases, due to the reliability and... 

    Optimization of the Dose Distribution in the Brachytherapy Using the Genetic Algorithm in Order to Increase the Absorbed Dose in the Cancer Tumor and to Reduce It in the Healthy Tissues

    , M.Sc. Thesis Sharif University of Technology Naderi, Hossein (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    Prostate cancer is the second most common cancer in men and the fourth most common cancer in all cancers. Cancer treatment is done according to the type of cancer and its diagnosis stage with different treatment methods and plans. Brachytherapy is one of the most common methods of cancer treatment along with teletherapy, surgery and chemotherapy. In this method, the source of radiation is located near or inside the tumor, and its advantage is to achieve a lower dose ratio of healthy tissue to the tumor is lower compared to teletherapy. One of the challenges in brachytherapy is to prescribe the appropriate treatment plan for the patient, so that the maximum dose of sources reaches the... 

    High Dimensional Sparse Learning in Distributed Systems

    , M.Sc. Thesis Sharif University of Technology Borghi, Hanieh (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    Distributed learning has been a popular area of machine learning for researchers according to having access to an unprecedented amount of data distributed over many clients in a network. Moreover, high dimensional learning, when the dimensions of data are high but the effective features are low, has great usage in learning especially in medical science. In this paper, we attempted to develop a method for learning high-dimensional sparse problems in a distributed manner, whit a star shape network. Our main focus in this research is on optimizing the communication flow in the network. The prominent idea of our proposed method is to extract the main feature in the first step, then continuing... 

    Haploblock Detection Based on Reads and Population Structure

    , M.Sc. Thesis Sharif University of Technology Akbari, Elahe (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    Human is diploid specie that inherits a set of chromosomes from their mother and a set from their father. The process of separating the nucleotide content of a set of extracted maternal and paternal chromosomes for an individual or a population is called phasing the genome of the individual or the population. The placement of any two variants relative to each other in diploid species is possible in two forms: cis (placement of both variants on one chromosome), and trans (placement of variants on different chromosomes). Each of these conditions leads to different phenotypes. Thus, understanding how variants are placed relative to each other is a crucial problem in human biology which is... 

    Presentation and Modeling of a New Nanocomposite Shield Against Gamma Radiation Based on Simulation and Computational Tools

    , M.Sc. Thesis Sharif University of Technology Arvaneh, Ali (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    In this study, using the MCNPX computer code based on the Monte Carlo method, the properties of protection against gamma-rays of the glass system with the combination of (55-x)Bi2O3-15Pb3O4-20Al2O3-10ZnO-xTiO2 with certain concentrations (x= 0, 5, 10, 15, 20, 25, 30 and 35 mol percent) and in nano and micro dimensions by calculating several parameters related to photon attenuation such as half value layer (HVL), Tenth value layer (TVL), mean free range (MFP), mass attenuation coefficient (m), linear attenuation coefficient (l), effective atomic number (Zeff) and buildup factor (BF) for We investigated different energy levels in the range of 1500-100 keV. To verify the simulation results,... 

    Inference of Recombination Rate in Iranian Population Genetics

    , M.Sc. Thesis Sharif University of Technology Ansari, Ehsan (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    Population genetics studies the distribution and changes in allele frequencies under the influence of five main evolutionary processes: natural selection, genetic drift, mutation, gene flow, and recombination. Among these, the recombination process can influence a wide range of biological processes by rearranging genes, repairing DNA structure, and participating actively in cell division mechanisms. Recombination has the ability to create genetic diversity through gene rearrangement, which is the main reason for creating diversity and evolution in organisms. Models such as Hill-Robertson have proven the influential role of recombination in accelerating evolutionary mechanisms. Also,... 

    Genome-wide Association Studies: Controlling False Discovery Rate using Knockoffs

    , M.Sc. Thesis Sharif University of Technology Kafi, Mahdi (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    In recent years, with the advancement of genetics technologies, many data from this field have been made available to researchers. Therefore, many analytical problems have been defined for these data. Genome-wide association studies, or GWAS for short, is one of these issues that deals with finding genetic positions affecting traits or diseases. Common approaches to this problem either examine genetic variants one by one or fail to consider the specific structure of genetic data. Also, both mentioned approaches do not provide a guarantee to control the rate of false positives. In this thesis, an attempt has been made to propose a method to solve the GWAS problem by using the new statistical... 

    Development of Software Based on Statistical Iterative Algorithm in the Reconstruction of Sparse View CT images

    , M.Sc. Thesis Sharif University of Technology Jamaati, Sayna (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    X-ray Computed Tomography (CT) is a widely used medical imaging technique that provides cross-sectional images by measuring the attenuation of X-rays in the body. However, the increasing use of CT has raised concerns about the potential long-term risks associated with radiation exposure. Various approaches have been proposed to reduce radiation dose, and one of the latest methods is sparse-view CT, which has gained popularity due to its lower challenges compared to other techniques. In sparse-view CT, data acquisition is restricted to specific angles, resulting in a significant reduction in radiation dose. However, this approach can introduce streak artifacts in the reconstructed images due... 

    Designing a System for Pulse Pile-Up Processing in Gamma Ray Spectroscopy Based on Digital Method

    , M.Sc. Thesis Sharif University of Technology Hojjat, Saeed (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    In Radiation Detection Systems applied in Spectroscopy and Imaging, if the rate of particle incidence with detector is high, the output pulses being stacked up on each other will be expected, which is known as “Pulse Pile-up”. Pulse pile-up might result in a serious disorder of energy and timing data expected from the pulses. In recent decades and after successful implementation of pile-up rejection methods on analog circuits, considering development and progression in the field of digital, different algorithms based on pileup correction methods have been developed to obtain all spectrum information, whether energy, rise time and recorded pulses. Such methods can be compared in different... 

    Estimation of Pressure Fluctuation Coefficient in Stilling Basins Using Computational Intelligent Models

    , M.Sc. Thesis Sharif University of Technology Mazandarani, Mahan (Author) ; Shamsai, Abolfazl (Supervisor)
    Abstract
    Hydraulic jump is a significant hydraulic phenomenon that occurs in stilling basins and causes energy dissipation of water flow. Due to the severe pressure fluctuations, cavitation, and fatigue damage to concrete materials, hydraulic jump can cause damage to the stilling basin and its related components. Therefore, studying pressure fluctuations is one of the essential topics in the safe design and operation of stilling basins. Due to the nonlinear relationship between the effective variables in the pressure fluctuation phenomenon, the use of computational intelligent models that can extract the relationship between the effective variables is necessary. In this study, laboratory data... 

    Fundamental Bounds for Clustering of Bernoulli Mixture Models

    , M.Sc. Thesis Sharif University of Technology Behjati, Amin (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    A random vector with binary components that are independent of each other is referred to as a Bernoulli random vector. A Bernoulli Mixture Model (BMM) is a combination of a finite number of Bernoulli models, where each sample is generated randomly according to one of these models. The important challenge is to estimate the parameters of a Bernoulli Mixture Model or to cluster samples based on their source models. This problem has applications in bioinformatics, image recognition, text classification, social networks, and more. For example, in bioinformatics, it pertains to clustering ethnic groups based on genetic data. Many studies have introduced algorithms for solving this problem without... 

    Fully Automatic Segmentation of Pelvic CT Images based on Deep Learning Methods

    , M.Sc. Thesis Sharif University of Technology Ghaedi, Elnaz (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    The initial step in radiotherapy treatment planning involves delineating the clinical target volumes (CTVs) and organs at risk (OARs). However, manual contouring is a time-consuming, labor-intensive, and subjective process. This study explores the potential of utilizing convolutional neural networks (CNNs) as an automated segmentation tool and an alternative to manual delineation. 218 Computed Tomography (CT) scans were gathered from two local hospitals in Tehran and the Whole Abdominal Organ Dataset (WORD). We employed ResUNet, a variant of UNet, as well as the original UNet from the Medical Open Network for AI (MONAI), an open-source framework for Deep Learning (DL) in healthcare imaging,... 

    Laboratory Investigation of Hydraulic & Constructional Effect of Sills on Dissipation of Energy in the Stepped Spillway

    , M.Sc. Thesis Sharif University of Technology Sedaghatnezhad, Sara (Author) ; shamsaee, Abolfazl (Supervisor)
    Abstract
    Chutes and stepped spillways are used to provide controlled release of flows and overflow in flood regimes from a dam into the downstream area. The main purpose of steps is to produce considerable energy dissipation along the chute and reduce the size of the required downstream energy dissipation basin. Many researches conducted on this matter and the effects of different factors like the height of steps, the number of steps, the different shapes of steps – mild step and end-sill step – influencing on energy dissipation have been studied. In this study, three different stepped spillway experimental models with different heights (5, 8 and 10 cm) and different number of steps developed, and... 

    Discrimination of Neutron and Gamma Spectrum Using a Method Based on Digital Filters

    , M.Sc. Thesis Sharif University of Technology Valipour, Mahdi (Author) ; Hosseini, Abolfazl (Supervisor)
    Abstract
    Since the beginning of discussion on neutron-gamma discrimination, different methods were suggested for this purpose. In early 2000s, Analogue methods were mainly used to discriminate the spectrum in mixed fields which mostly depends on electronic modules used in the lab setup; Nowadays, with improvements in digital pulse processing techniques, analyzing mixed neutron-gamma fields for pulse discrimination is also available.In this research, the recent MC developed toolkit called GEANT4 is used to simulate the 3-inch BC501A scintillation detector and 500 mCi Am-Be source (that emits neutron and gamma at the same time). For the next step, an experiment with same source and detector was done... 

    Routing Techniques Using Nature-Inspired Metaheuristic Algorithms

    , M.Sc. Thesis Sharif University of Technology Nezamoleslami, Hossein (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    One of the complex problems is routing. This problem becomes more difficult and important in certain situations, which cannot be solved straightforwardly. In this thesis, a model for vehicle (ambulance) routing problem during hospital evacuation in disaster conditions is described and solved using Gray Wolf Optimization (GWO) algorithm in combination with a local search algorithm called Great Deluge Algorithm (GDA). It is shown that the combination of GWO and GDA can improve the efficiency of GWO and avoid local optima. The results are compared with some metaheuristic algorithms. To test the model of 11 hospitals in Tehran, three different modes have been considered, and in each mode, 7... 

    Deep Neural Networks: Tradeoff Between Compression and Communication Rates

    , M.Sc. Thesis Sharif University of Technology Najafiaghdam, Kossar (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    In recent years, the use of Deep Neural Networks in solving various problems has grown considerably. Possessing a large number of parameters, these networks have the ability to reconstruct complex functions and relations from large amounts of data and have been able to achieve the best results in a wide range of problems. But using these models comes with its own problems. These networks typically require considerable resources in order to run. This makes it inefficient or impossible to use them in systems with limited processing capabilities, e.g mobile phones. The existing approaches, e.g. the deployment of the model on a powerful server and network compression, have their own drawbacks... 

    Provide a Model for the Sitting of Hydroelectric Power Plants Using GIS and Multiple Criteria Decision FTOPSIS: A Case From Kelas Basin

    , M.Sc. Thesis Sharif University of Technology Darban Maghami, Alireza (Author) ; Shamsai, Abolfazl (Supervisor)
    Abstract
    Nowadays due to increasing environmental considerations and effort to reducing of the fossil fuels consumption, the necessity of hydroelectric power plants development is emerged. The purpose of this study is to suggest a method of spatial analysis for finding sites with appropriate potential for construction of these power plants, using TOPSIS and GIS. In this research, using the Python programming language, in software environment of Arc GIS version 9.3, local hydrological model was generated using the DEM layer and using of streams ordering methods, the overall situation along the river were processed. In the next step, with using of fuzzy TOPSIS algorithm implementation in software... 

    Comparison of River Daily Runoff Simulation Results using Time Series and IHACRES Rainfall-runoff Model

    , M.Sc. Thesis Sharif University of Technology Rahsepar Tolouei, Talaye (Author) ; Shamsaei, Abolfazl (Supervisor)
    Abstract
    Hydrologic models are the best tools to reduce hydrological uncertainties in rivers runoff estimation. Considering structure of model and calibration of parameters, there are several approaches to extend. In this study, we try to simulate daily river runoff by using two different approaches and then compare the results of them with each other. In first approach, IHACRES model is used to simulate rainfall- runoff, which is a conceptual model based on rainfall, runoff and evapotranspiration or temperature data. This model uses conceptual part to estimate effective rainfall and also it uses a transformation function to transform effective rainfall to output flow. This model works in daily time... 

    Identifying Core Genes in Estimation of Missing Gene Expressions

    , M.Sc. Thesis Sharif University of Technology Darvish Shafighi, Shadi (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    Characterizing cellular states in response to various disease conditions is an important issue which is addressed by different methods such as Large-scale gene expression profiling. One of the most important challenges in front of bioinformaticians is the loss of data because expression profiling is still very expensive. It is understood that profiling a group of selected genes could be enough for understanding all of the gene expression profile.In this research, we propose a fast method for estimation of the missing values inlow-rank matrices. We consider the highly correlated expression profiles as a low-rank matrix. Then, we used this new method in a proposed algorithm which will select...