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    Emergency Medical Service Centers Location

    , M.Sc. Thesis Sharif University of Technology Roostaei, Ali (Author) ; Eshghi, Kourosh (Supervisor)
    Abstract
    The Emergency Medical Services (EMS) have a major role in decreasing the mortality rate and reducing the non-reversible effects of injuries by on time care to patients and transporting them to hospitals if it is needed. Since there is an important goal directly related to the human life, any research or study to improve the performance of EMS is highly recommended. One of the most important parameters in evaluation of EMS is to measure the coverage time of a demand. The locations of EMS play substantial role to decrease the response time. So the locations of EMS stations are very important especially in large and populated cities. Mainly, there are three problems that EMS managers should... 

    Study on Biodiesel Production Using Engineered Lipases

    , M.Sc. Thesis Sharif University of Technology Char Roostaei, Hamzeh (Author) ; Kazemeini, Mohammad (Supervisor)
    Abstract
    Biodiesel has drawn the attention of many researches to itself as a replacing source for crude oil, recently. Transesterification is one of the most popular methods used for biodiesel production. Enzyme transesterification is a more simple method in comparison with acidic or basic transesterification. However, the high price and low yield of enzyme transesterification has caused many obstacles in its application. Enzyme engineering has gained much attention as a way to improve enzyme performance. In this thesis, biodiesel production by a native enzyme named Bacillus thermocatenulatus, and two engineered-enzymes is studied. First, effective parameters and variables in biodiesel production by... 

    Emergence of Hopf bifurcation in an extended SIR dynamic

    , Article PLoS ONE ; Volume 17, Issue 10 October , 2022 ; 19326203 (ISSN) Roostaei, A ; Barzegar, H ; Ghanbarnejad, F ; Sharif University of Technology
    Public Library of Science  2022
    Abstract
    In this paper, the original SIR model is improved by considering a new compartment, representing the hospitalization of critical cases. A system of differential equations with four blocks is developed to analyze the treatment of severe cases in an Intensive Care Unit (ICU). The outgoing rate of the infected individuals who survive is divided into nI and bI/1+b where the second term represents the transition rate of critical cases that are hospitalized in ICU. The findings demonstrate the existence of forward, backward and Hopf bifurcations in various ranges of parameters. © 2022 Roostaei et al. This is an open access article distributed under the terms of the Creative Commons Attribution... 

    Investigation of the Effect of Slip Length on the Electrokinetic Behavior of Conical-Shaped Nanochannels

    , M.Sc. Thesis Sharif University of Technology Roostaei, Mahmoud (Author) ; Mohammadi, Ali Asghar (Supervisor)
    Abstract
    Conical nanochannels have desirable electrokinetic properties due to asymmetry,including ionic current rectification and ion selectivity. The present study numerically addressed the effect of slip length on the ionic current rectification and ion selectivity in conical-shaped electrolyte-loaded nanochannels with and without a coated polyelectrolyte layer. The electrolyte was considered a salted incompressible Newtonian fluid. The polyelectrolyte layer was also modeled as a rigid and charged porous solid saturated with a salted Newtonian fluid. The electrolyte-polyelectrolyte layer interface was modeled as a surface, considering ion partitioning with distinct physical properties across the... 

    Numerical Modeling and Experimental Investigation of the Efficiency of the Laser-assisted Machining for Ceramics

    , Ph.D. Dissertation Sharif University of Technology Roostaei, Hossein (Author) ; Movahhedy, Mohammad Reza (Supervisor) ; Shoja Razavi, Reza (Co-Supervisor)
    Abstract
    Laser-assisted machining is nowadays considered as an alternative to conventional machining processes including ceramics grinding, which has provided the basis for extensive experimental and numerical studies in this field. Since the main difference between laser-assisted machining and conventional machining is in the presence of lasers, the main purpose of this study was to investigate the effects of laser on the laser assisted machining process. In this regard, in the first step the process of laser heating to the ceramic workpiece has been studied experimentally and numerically by finite element method. The material used in this research is a slip cast fused silica ceramic. The... 

    Analysis of Heat Transfer in Laser Assisted Machining of Slip Cast Fused Silica Ceramics

    , Article 7th CIRP Conference on High Performance Cutting, HPC 2016, 31 May 2016 through 2 June 2016 ; Volume 46 , 2016 , Pages 571-574 ; 22128271 (ISSN) Roostaei, H ; Movahhedy, M. R ; Ihlefeldt S ; Wertheim R ; Hochmuth C ; Putz M ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Machining of ceramics often involves many challenges due to their high hardness, brittleness, and low thermal properties. Laser assisted machining (LAM) is a promising technology for improving the machinability of hard-to-cut materials. In this work, laser assisted machining of slip cast fused silica (SCFS) ceramics is investigated by presenting a numerical thermal analysis of laser effects on material behaviour. A transient three-dimensional heat transfer analysis for laser assisted turning of SCFS is performed using finite element method. Temperature distributions in SCFS cylindrical specimens are obtained. Experimental results are provided to validate the numerical results  

    Channelopathy-related SCN10A gene variants predict cerebellar dysfunction in multiple sclerosis

    , Article Neurology ; Volume 86, Issue 5 , 2016 , Pages 410-417 ; 00283878 (ISSN) Roostaei, T ; Sadaghiani, S ; Park, M. T. M ; Mashhadi, R ; Nazeri, A ; Noshad, S ; Salehi, M. J ; Naghibzadeh, M ; Moghadasi, A. N ; Owji, M ; Doosti, R ; Hashemi Taheri, A. P ; Rad, A. S ; Azimi, A ; Chakravarty, M. M ; Voineskos, A. N ; Nazeri, A ; Sahraian, M. A ; Sharif University of Technology
    Lippincott Williams and Wilkins  2016
    Abstract
    Objective: To determine the motor-behavioral and neural correlates of putative functional common variants in the sodium-channel NaV1.8 encoding gene (SCN10A) in vivo in patients with multiple sclerosis (MS). Methods: We recruited 161 patients with relapsing-onset MS and 94 demographically comparable healthy participants. All patients with MS underwent structural MRI and clinical examinations (Expanded Disability Status Scale [EDSS] and Multiple Sclerosis Functional Composite [MSFC]). Whole-brain voxel-wise and cerebellar volumetry were performed to assess differences in regional brain volumes between genotype groups. Resting-state fMRI was acquired from 62 patients with MS to evaluate... 

    Majorana zero-energy mode and fractal structure in fibonacci-kitaev chain

    , Article Journal of the Physical Society of Japan ; Volume 86, Issue 11 , 2017 ; 00319015 (ISSN) Ghadimi, R ; Sugimoto, T ; Tohyama, T ; Sharif University of Technology
    2017
    Abstract
    We theoretically study a Kitaev chain with a quasiperiodic potential, where the quasiperiodicity is introduced by a Fibonacci sequence. Based on an analysis of the Majorana zero-energy mode, we find the critical p-wave superconducting pairing potential separating a topological phase and a non-topological phase. The topological phase diagram with respect to Fibonacci potentials follow a self-similar fractal structure characterized by the box-counting dimension, which is an example of the interplay of fractal and topology like the Hofstadter's butterfly in quantum Hall insulators. © 2017 The Physical Society of Japan  

    Accelerating federated edge learning

    , Article IEEE Communications Letters ; Volume 25, Issue 10 , 2021 , Pages 3282-3286 ; 10897798 (ISSN) Nguyen, T. D ; Balef, A. R ; Dinh, C. T ; Tran, N. H ; Ngo, D. T ; Anh Le, T ; Vo, P. L ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    Transferring large models in federated learning (FL) networks is often hindered by clients' limited bandwidth. We propose $ extsf {FedAA}$ , an FL algorithm which achieves fast convergence by exploiting the regularized Anderson acceleration (AA) on the global level. First, we demonstrate that FL can benefit from acceleration methods in numerical analysis. Second, $ extsf {FedAA}$ improves the convergence rate for quadratic losses and improves the empirical performance for smooth and strongly convex objectives, compared to FedAvg, an FL algorithm using gradient descent (GD) local updates. Experimental results demonstrate that employing AA can significantly improve the performance of FedAvg,... 

    Study of the effect of thermal dispersion on internal natural convection in porous media using fourier series

    , Article Transport in Porous Media ; Volume 131, Issue 2 , 2020 , Pages 537-568 Fahs, M ; Graf, T ; Tran, T. V ; Ataie Ashtiani, B ; Simmons, C. T ; Younes, A ; Sharif University of Technology
    Springer  2020
    Abstract
    Natural convection in a porous enclosure in the presence of thermal dispersion is investigated. The Fourier–Galerkin (FG) spectral element method is adapted to solve the coupled equations of Darcy’s flow and heat transfer with a full velocity-dependent dispersion tensor, employing the stream function formulation. A sound implementation of the FG method is developed to obtain accurate solutions within affordable computational costs. In the spectral space, the stream function is expressed analytically in terms of temperature, and the spectral system is solved using temperature as the primary unknown. The FG method is compared to finite element solutions obtained using an in-house code... 

    A probabilistic artificial neural network-based procedure for variance change point estimation

    , Article Soft Computing ; Vol. 19, issue. 3 , May , 2014 , pp. 691-700 ; ISSN: 14327643 Amiri, A ; Niaki, S. T. A ; Moghadam, A. T ; Sharif University of Technology
    2014
    Abstract
    Control charts are useful tools of monitoring quality characteristics. One of the problems of employing a control chart is that the time it alarms is not synchronic with the time when assignable cause manifests itself in the process. This makes difficult to search and find assignable causes. Knowing the real time of manifestation of assignable cause (change point) helps to find assignable cause(s) sooner and eases corrective actions to be taken. In this paper, a probabilistic neural network (PNN)-based procedure was developed to estimate the variance change point of a normally distributed quality characteristic. The PNN was selected based on trial and error among different types of... 

    Two studies of framework-usage templates extracted from dynamic traces

    , Article IEEE Transactions on Software Engineering ; Volume 38, Issue 6 , 2012 , Pages 1464-1487 ; 00985589 (ISSN) Heydarnoori, A ; Czarnecki, K ; Binder, W ; Bartolomei, T. T ; Sharif University of Technology
    2012
    Abstract
    Object-oriented frameworks are widely used to develop new applications. They provide reusable concepts that are instantiated in application code through potentially complex implementation steps such as subclassing, implementing interfaces, and calling framework operations. Unfortunately, many modern frameworks are difficult to use because of their large and complex APIs and frequently incomplete user documentation. To cope with these problems, developers often use existing framework applications as a guide. However, locating concept implementations in those sample applications is typically challenging due to code tangling and scattering. To address this challenge, we introduce the notion of... 

    On the throughput and outage probability of multi-relay networks with imperfect power amplifiers

    , Article IEEE Transactions on Wireless Communications ; Volume 14, Issue 9 , May , 2015 , Pages 4994-5008 ; 15361276 (ISSN) Makki, B ; Svensson, T ; Eriksson, T ; Nasiri Kenari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    This paper studies the energy-limited performance of multi-relay networks. Taking the properties of the power amplifiers (PAs) into account, we derive closed-form expressions for the optimal power allocation, the outage probability and the throughput in the cases with a sum consumed energy constraint. Moreover, we analyze the diversity and the multiplexing gains of the PA-aware systems. Finally, we investigate the performance of large-scale multi-relay networks and develop efficient multi-relay systems with low cooperation overhead. The numerical and the analytical results show that the inefficiency of the PAs affects the outage probability and the throughput of the multi-relay systems... 

    Online jointly estimation of hysteretic structures using the combination of central difference Kalman filter and Robbins–Monro technique

    , Article JVC/Journal of Vibration and Control ; 2020 Amini Tehrani, H ; Bakhshi, A ; Yang, T. T. Y ; Sharif University of Technology
    SAGE Publications Inc  2020
    Abstract
    Rapid assessment of structural safety and performance right after the occurrence of significant earthquake shaking is crucial for building owners and decision-makers to make informed risk management decisions. Hence, it is vital to develop online and pseudo-online health monitoring methods to quantify the health of the building right after significant earthquake shaking. Many Bayesian inference–based methods have been developed in the past which allow the users to estimate the unknown states and parameters. However, one of the most challenging part of the Bayesian inference–based methods is the determination of the parameter noise covariance matrix. It is especially difficult when the number... 

    Online probabilistic model class selection and joint estimation of structures for post-disaster monitoring

    , Article JVC/Journal of Vibration and Control ; 2020 Amini Tehrani, H ; Bakhshi, A ; Yang, T. T. Y ; Sharif University of Technology
    SAGE Publications Inc  2020
    Abstract
    Online selection of the appropriate model and identifying its parameters based on measured vibrational data are among the challenging issues in dynamic system identification. After a severe earthquake, quick monitoring and assessment of structural health status play a crucial role in effective critical risk management for the building owners and decision-makers. The Bayesian multiple modeling approach is a suitable tool for optimal model class selection, which is used in this article mainly for improving data fitting precision, decreasing dimensions of structural unknown vector through removing unnecessary parameters, detecting the occurrence and type of predominant phenomenon related to... 

    Online probabilistic model class selection and joint estimation of structures for post-disaster monitoring

    , Article JVC/Journal of Vibration and Control ; Volume 27, Issue 15-16 , 2021 , Pages 1860-1878 ; 10775463 (ISSN) Amini Tehrani, H ; Bakhshi, A ; Yang, T. T .Y ; Sharif University of Technology
    SAGE Publications Inc  2021
    Abstract
    Online selection of the appropriate model and identifying its parameters based on measured vibrational data are among the challenging issues in dynamic system identification. After a severe earthquake, quick monitoring and assessment of structural health status play a crucial role in effective critical risk management for the building owners and decision-makers. The Bayesian multiple modeling approach is a suitable tool for optimal model class selection, which is used in this article mainly for improving data fitting precision, decreasing dimensions of structural unknown vector through removing unnecessary parameters, detecting the occurrence and type of predominant phenomenon related to... 

    Online jointly estimation of hysteretic structures using the combination of central difference kalman filter and robbins–monro technique

    , Article JVC/Journal of Vibration and Control ; Volume 27, Issue 1-2 , 2021 , Pages 234-247 ; 10775463 (ISSN) Amini Tehrani, H ; Bakhshi, A ; Yang, T. T. Y ; Sharif University of Technology
    SAGE Publications Inc  2021
    Abstract
    Rapid assessment of structural safety and performance right after the occurrence of significant earthquake shaking is crucial for building owners and decision-makers to make informed risk management decisions. Hence, it is vital to develop online and pseudo-online health monitoring methods to quantify the health of the building right after significant earthquake shaking. Many Bayesian inference–based methods have been developed in the past which allow the users to estimate the unknown states and parameters. However, one of the most challenging part of the Bayesian inference–based methods is the determination of the parameter noise covariance matrix. It is especially difficult when the number... 

    Noninvasive estimation of tissue temperature via high-resolution spectral analysis techniques

    , Article IEEE Transactions on Biomedical Engineering ; Volume 52, Issue 2 , 2005 , Pages 221-228 ; 00189294 (ISSN) Nasiri Amini, A ; Ebbini, E. S ; Georgiou, T. T ; Sharif University of Technology
    2005
    Abstract
    We address the noninvasive temperature estimation from pulse-echo radio frequency signals from standard diagnostic ultrasound imaging equipment. In particular, we investigate the use of a high-resolution spectral estimation method for tracking frequency shifts at two or more harmonic frequencies associated with temperature change. The new approach, employing generalized second-order statistics, is shown to produce superior frequency shift estimates when compared to conventional high-resolution spectral estimation methods Seip and Ebbini (1995). Furthermore, temperature estimates from the new algorithm are compared with results from the more commonly used echo shift method described in Simon... 

    Vulnerability modeling of cryptographic hardware to power analysis attacks

    , Article Integration, the VLSI Journal ; Volume 42, Issue 4 , 2009 , Pages 468-478 ; 01679260 (ISSN) Moradi, A ; Salmasizadeh, M ; Manzuri Shalmani, M. T ; Eisenbarth, T ; Sharif University of Technology
    2009
    Abstract
    Designers and manufacturers of cryptographic devices are always worried about the vulnerability of their implementations in the presence of power analysis attacks. This article can be categorized into two parts. In the first part, two parameters are proposed to improve the accuracy of the latest hypothetical power consumption model, so-called toggle-count model, which is used in power analysis attacks. Comparison between our proposed model and the toggle-count model demonstrates a great advance, i.e., 16%, in the similarity of hypothetical power values to the corresponding values obtained by an analog simulation. It is supposed that the attacker would be able to build such an accurate power... 

    Partial discharges pattern recognition of transformer defect model by LBP & HOG features

    , Article IEEE Transactions on Power Delivery ; 2018 ; 08858977 (ISSN) Firuzi, K ; Vakilian, M ; Phung, B. T ; Blackburn, T. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    Partial discharge (PD) measurement and identification have great importance to condition monitoring of power transformers. In this paper a new method for recognition of single and multi-source of PD based on extraction of high level image features have been introduced. A database, involving 365 samples of phase-resolved PD (PRPD) data, is developed by measurement carried out on transformer artificial defect models (having different sizes of defect) under a specific applied voltage, to be used for proposed algorithm validation. In the first step, each set of PRPD data is converted into grayscale images to represent different PD defects. Two “image feature extraction” methods, the Local Binary...