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    Activated carbon/metal-organic framework nanocomposite: Preparation and photocatalytic dye degradation mathematical modeling from wastewater by least squares support vector machine

    , Article Journal of Environmental Management ; Volume 233 , 2019 , Pages 660-672 ; 03014797 (ISSN) Mahmoodi, N. M ; Abdi, J ; Taghizadeh, M ; Taghizadeh, A ; Hayati, B ; Shekarchi, A. A ; Vossoughi, M ; Sharif University of Technology
    Academic Press  2019
    Abstract
    Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (Eg) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%).... 

    A resilience-based practical platform and novel index for rapid evaluation of urban water distribution network using hybrid simulation

    , Article Sustainable Cities and Society ; Volume 82 , 2022 ; 22106707 (ISSN) Ebrahimi, A. H ; Mortaheb, M. M ; Hassani, N ; Taghizadeh yazdi, M ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    This article proposes a novel index along with a user-friendly platform for resilience evaluation of the urban water distribution networks (WDN). WDN is of great importance in preserving the safety and sustainability of communities and cities. Resilience of a given system results in its sustainability. In recent years, many studies have focused on resilient urban WDN. However, these studies did not provide a comprehensive evaluation index and platform that could simultaneously consider hydraulic analysis, resilience parameters, and significant uncertainties. In this study, a novel resilience index was defined, and a user-friendly and practical platform (REWAT) was developed to calculate the... 

    Dynamic comparison of segmentary scapulohumeral rhythm between athletes with and without impingement syndrome

    , Article Iranian Journal of Radiology ; Vol. 11, issue. 2 , 2014 Taghizadeh Delkhoush, C ; Maroufi, N ; Ebrahimi Takamjani, I ; Farahmand, F ; Shakourirad, A ; Haghani, H ; Sharif University of Technology
    2014
    Abstract
    Background: Patients who have shoulder pain usually have compensatory or contributory deviation of shoulder motion during arm elevation. In the traditional scapulohumeral rhythm, the share of the acromioclavicular (AC) and the sternoclavicular (SC) joint movements and also the role of AC internal rotation angle are unknown. Objectives: The main purpose of this study was to measure and compare the segmentary scapulohumeral rhythm (SSHR) during scapular arm elevation at a steady rotational speed in athletes with and without impingement syndrome. Patients and Methods: Using a speedometer, the maximum speed of arm elevation was measured in 21 men in each of the involved and uninvolved groups.... 

    A novel graphical approach to automatic abstraction in reinforcement learning

    , Article Robotics and Autonomous Systems ; Volume 61, Issue 8 , 2013 , Pages 821-835 ; 09218890 (ISSN) Taghizadeh, N ; Beigy, H ; Sharif University of Technology
    2013
    Abstract
    Recent researches on automatic skill acquisition in reinforcement learning have focused on subgoal discovery methods. Among them, algorithms based on graph partitioning have achieved higher performance. In this paper, we propose a new automatic skill acquisition framework based on graph partitioning approach. The main steps of this framework are identifying subgoals and discovering useful skills. We propose two subgoal discovery algorithms, which use spectral analysis on the transition graph of the learning agent. The first proposed algorithm, incorporates k′-means algorithm with spectral clustering. In the second algorithm, eigenvector centrality measure is utilized and options are... 

    Improved unity-STF sturdy MASH ΣΔ modulator for low-power wideband applications

    , Article Electronics Letters ; Volume 51, Issue 23 , November , 2015 , Pages 1941-1942 ; 00135194 (ISSN) Taghizadeh, M ; Sadughi, S ; Sharif University of Technology
    Institution of Engineering and Technology  2015
    Abstract
    A novel sturdy multi-stage noise-shaping sigma-delta modulator that cancels the first-stage quantisation error at the output of the modulator is presented. Since any stage of the modulator has unity signal transfer function, the modulator would be very robust to circuit non-idealities such as finite op-amp gain. Furthermore, the signal processing timing issue in the critical paths of the proposed topology has been relaxed due to shifting the delay of the last integrator to the feedback path of the modulator. Moreover, this topology can be implemented in the circuit level by a fewer active blocks. Therefore, it practically would be suitable for low-voltage and low-oversampling applications.... 

    Relaxed timing issue in global feedback paths of unity-STF SMASH sigma delta modulator architecture

    , Article ARPN Journal of Engineering and Applied Sciences ; Volume 12, Issue 17 , 2017 , Pages 4872-4876 ; 18196608 (ISSN) Taghizadeh, M ; Sadughi, S ; Sharif University of Technology
    2017
    Abstract
    This Paper presents a practical way to improve signal bandwidth and resolution in a Sturdy Multi-Stage Noise- Shaping (SMASH) sigma delta modulator. In this way, the processing timing issue in the critical paths of the proposed architecture has been relaxed due to the shifting delay of the modulator loop filter of each stage to the its feedback path. The proposed Unity-STF SMASH architecture, which is realized with several efficient techniques, would be robust to circuit non-idealities such as finite op-amp DC gain. Furthermore the topology can be implemented by a fewer active blocks, suitable it for low power, high operation speed applications. © 2006-2017 Asian Research Publishing Network... 

    Seismic Behavior of Reinforced Concrete Frames Retrofitted by Pre-Stressed Steel Strips

    , M.Sc. Thesis Sharif University of Technology Taghizadeh, Reza (Author) ; Moghaddam, Hassan (Supervisor)
    Abstract
    With occurring severe earthquakes, damages of columns in RC buildings can lead to overall failure and collapse. So retrofitting of such columns that do not comply with the design requirements is necessary to prevent such phenomena. A variety of methods has been introduced so far for retrofitting. The key factors in determining the retrofitting methods are being economic and easily implemented in the design. Confining concrete columns with pre-stressed steel strips is a new technique that is simple and economic. Previous experimental experiments have shown that this method can enhance ductility and overall seismic behavior of such columns.
    In the present study three and six story frames... 

    An Approach for Cancer Diagnosis Based on Graph Modeling

    , M.Sc. Thesis Sharif University of Technology Taghizadeh, Ghasem (Author) ; Habibi, Jafar (Supervisor)
    Abstract
    Digital image analysis of histological datasets is a currently expanding field of research. Histological images are inherently complex in nature and contain a wide variety of visual information. Graph-based methods have recently gained immense popularity, as these methods can effectively describe tissue architecture and provide adequate numeric information for subsequent computer-based analysis. Graphs have the ability to represent spatial arrangements and neighborhood relationships of different tissue components, which are essential characteristics observed visually by pathologists during the investigation of specimens. In this thesis, we proposed an automatic approach for classification... 

    Second-Order Homogenization of BCC Lattice Structures to Strain-Gradient Continuum with the Aid of Machine Learning

    , M.Sc. Thesis Sharif University of Technology Taghizadeh, Sina (Author) ; Asghari, Mohsen (Supervisor)
    Abstract
    Engineering of properties was previously not possible. With the advent of additive manufacturing, it became possible to produce structures with architected microstructures, known as lattice structures. The popularity of these structures, due to their lightweight and tunable properties, has increased the importance of their optimal mechanical analysis. Since direct analysis of these structures is computationally prohibitive due to their high level of detail, homogenization methods have been proposed as an alternative. Since these methods couldn't capture size effects, higher-order homogenization methods were introduced. However, despite their good accuracy, these methods are still rarely used... 

    A hierarchical artificial neural network for transport energy demand forecast: Iran case study

    , Article Neural Network World ; Volume 20, Issue 6 , 2010 , Pages 761-772 ; 12100552 (ISSN) Kazemi, A ; Shakouri, H .G ; Menhaj, M. B ; Mehregan, M. R ; Neshat, N ; Asgharizadeh, E ; Taghizadeh, M. R ; Sharif University of Technology
    2010
    Abstract
    This paper presents a neuro-based approach for annual transport energy demand forecasting by several socio-economic indicators. In order to analyze the influence of economic and social indicators on the transport energy demand, gross domestic product (GDP), population and total number of vehicles are selected. This approach is structured as a hierarchical artificial neural networks (ANNs) model based on the supervised multi-layer perceptron (MLP), trained with the back-propagation (BP) algorithm. This hierarchical ANNs model is designed properly. The input variables are transport energy demand in the last year, GDP, population and total number of vehicles. The output variable is the energy... 

    A planar neuro-musculoskeletal arm model in post-stroke patients

    , Article Biological Cybernetics ; Volume 112, Issue 5 , 2018 , Pages 483-494 ; 03401200 (ISSN) Asghari, M ; Behzadipour, S ; Taghizadeh, G ; Sharif University of Technology
    2018
    Abstract
    Mathematical modeling of the neuro-musculoskeletal system in healthy subjects has been pursued extensively. In post-stroke patients, however, such models are very primitive. Besides improving our general understanding of how stroke affects the limb motions, they can be used to evaluate rehabilitation strategies by computer simulations before clinical evaluations. A planar neuro-musculoskeletal arm model for post-stroke patients is developed. The main idea is to use a set of new coefficients, Muscle Significance Factors (MSF), to incorporate the effects of stroke in the muscle control performance. The model uses the optimal control theory to mimic the performance of the CNS and a two-link... 

    Margins of postural stability in parkinson’s disease: an application of control theory

    , Article Frontiers in Bioengineering and Biotechnology ; Volume 11 , 2023 ; 22964185 (ISSN) Rahmati, Z ; Behzadipour, S ; Taghizadeh, G ; Sharif University of Technology
    Frontiers Media SA  2023
    Abstract
    Introduction: Postural instability is a restrictive feature in Parkinson’s disease (PD), usually assessed by clinical or laboratory tests. However, the exact quantification of postural stability, using stability theorems that take into account human dynamics, is still lacking. We investigated the feasibility of control theory and the Nyquist stability criterion—gain margin (GM) and phase margin (PM)—in discriminating postural instability in PD, as well as the effects of a balance-training program. Methods: Center-of-pressure (COP) data of 40 PD patients before and after a 4-week balance-training program, and 20 healthy control subjects (HCs) (Study1) as well as COP data of 20 other PD... 

    Autonomous Skill Acquisition in Reinforcement Learning Based on Graph Clustering

    , M.Sc. Thesis Sharif University of Technology Taghizadeh, Nasrin (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Reinforcement Learning (RL) is a branch of machine learning that tries to improve agent’s behaviour through interaction with environment and receiving reinforcement signal. As the size of environment increases, decision-making would be more difficult and learning time will increase. On of the main approaches for decreasing learning complexity is to define skills. Skill is a behavioural unit consists of primitive actions. Humans learn and use a lot of skills in their life. Walking, eating, passing the door to reach kitchen and going to airport for travelling are examples of such skills that humans utilize them for daily activities. Agent can learn skills once and then uses them in other... 

    Semipolynomial kernel optimization based on the fisher method

    , Article IEEE International Workshop on Machine Learning for Signal Processing, 18 September 2011 through 21 September 2011 ; September , 2011 , Page(s): 1 - 6 ; 9781457716232 (ISBN) Taghizadeh, E ; Sadeghipoor, Z ; Manzuri, M. T ; Sharif University of Technology
    2011
    Abstract
    Kernel based methods are significantly important in the pattern classification problem, especially when different classes are not linearly separable. In this paper, we propose a new kernel, which is the modified version of the polynomial kernel. The free parameter (d) of the proposed kernel considerably affects the error rate of the classifier. Thus, we present a new algorithm based on the Fisher criterion to find the optimum value of d. Simulation results show that using the proposed kernel for classification leads to satisfactory results. In our simulation in most cases the proposed method outperforms the classification using the polynomial kernel  

    Optimization of a serpentine model for low-dispersion flows in micro channel turns

    , Article 5th International Conference on Perspective Technologies and Methods in MEMS Design, MEMSTECH 2009, Lviv-Polyana, 22 April 2009 through 24 April 2009 ; 2009 , Pages 136-140 ; 9789662191066 (ISBN) Fathollahi, E ; Afsharikia, S ; Taghizadeh Manzari, M.T ; Sharif University of Technology
    2009
    Abstract
    Chip-based micro fluidic separation systems often use serpentine channels to attain long separation lengths in a compact area. Such designs suffer from the dispersion, mostly 'racetrack' effect, due to the bends in the micro channels. The main goal of this paper is obtaining a model which has minimal racetrack in a serpentine geometry. A numerical analysis leads us to an optimized model which is different from previous attempts in this field. Our model uses modified turn radii, optimal length between bends with a constant zeta-potential boundary condition and a constant width through micro channel turns. It is shown that traveling fluid in this geometry has minimal dispersion as well as... 

    Study of Capillary Pressure Effect on Multiphase Flow in Hydrocarbon Reservoirs

    , M.Sc. Thesis Sharif University of Technology Biglarian, Hassan (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    Abstract
    One of the most important issues in the petroleum industry, is how to increase the oil production from hydrocarbon reservoirs. The optimum design of an enhanced oil recovery process needs the knowledge on the physical phenomena of the working flow in oil reservoirs. An important aspect of any oil recovery process is the effectiveness of process fluid in removing oil from the rock pores at microscopic scales, in a way that it determines the success or failure of the recovery process. Meanwhile, one of the most important factors on the fluid mobility and as a result the microscopic mobility efficiency is the pressure difference between different phases in narrow paths of porous media. This... 

    Simulation of Magnetohydrodynamic Flow in the MWEC Generator Duct Using OpenFOAM Software

    , M.Sc. Thesis Sharif University of Technology Azadi, Ehsan (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    Abstract
    Magnetohydrodynamic (MHD) flow is concerned with the interaction between the magnetic field and electrically conducting fluid flow. In this investigation, the MHD flow in the duct of magnetohydrodynamic wave energy conversion (MWEC) generator was simulated by use of OpenFOAM software. In the MWEC generator the reciprocating motion of ocean waves lead to electrically conducting fluid flow in the duct of this generator. By applying magnetic field perpendicular to this flow, electric current generate in the fluid. This generator has a higher efficiency compared with other ocean wave energy conversion generators. Firstly, to evaluate accuracy and performance of mhdFOAM code of OpenFOAM, three... 

    Comparison and Evaluation of the Performance of some Fundamental Models for Simulation of Naturally Fractured Hydrocarbon Reservoirs

    , M.Sc. Thesis Sharif University of Technology Mahmoudi, Siamak (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    Abstract
    Fractured reservoirs show a different behavior from common reservoirs because of the existence of a broad network of fractures. This phenomenon makes it necessary to apply special methods for fractured reservoirs in the procedure of reservoir simulation. Since twenty percent of petroleum content in the world is buried in fractured reservoirs, investigating these reservoirs is of great importance.
    The first step in simulation of these kinds of reservoirs is to come up with a geometrical model which can be used to take the fracture network influence into account. In the course for reaching such an objective, various models have been developed which are based on specific assumptions and in... 

    Petroleum Reservoir Simulation Using Combination Multi-scale Finite Volume Method and Streamline Method with Gravity Effects

    , M.Sc. Thesis Sharif University of Technology Bordbar, Amir (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    Abstract
    In this thesis the oil reservoir simulation is carried out by using a combination of fast Multi-scale finite volume method and Streamline method considering gravity effects. In this simulation, the governing equations for incompressible fluid flow in porous media are solved using the IMPES (implicit pressure- explicit saturation) viewpoint. Multi- scale method is rapid (equivalent on coarse-scale methods) and accurate (equivalent on fine-scale methods) in solving the pressure field. Using the pressure field obtained through this way combined with Darcy equation make us able to extract the conservative velocity field. In this study, analytical and numerical Streamline methods are used to... 

    Cosmological Black Hole

    , Ph.D. Dissertation Sharif University of Technology Taghizadeh Firouzjaee, Javad (Author) ; Mansouri, Reza (Supervisor)
    Abstract
    In the era of precision cosmology it is desirable to know if the collapse of an overdensity region within a FRW cosmological model leads to a black hole similar to that of Schwarzschild. Even the simple question of an event horizon within a dynamical universe is not a trivial one. This subject of studying collapsing over-densities within an expanding universe is called ”cosmological black holes”. Our aim is to construct such a black hole in the simplest possible scenario and study its similarities and differences to the familiar Schwarzschild one in vacuum. Therefore questions of rotating or charged black holes are not dealt with in our work. We insist, however, that the solution is dynamic...