Aerodynamic Optimization of Axial Transonic Compressor Blade by Adjoint Method Using Bump/ Local Blowing

, Ph.D. Dissertation Sharif University of Technology Khatibi Rad, Saeedeh (Author) ; Mazaheri, Karim (Supervisor)

Abstract

Transonic flow compressors are widely used today. In these systems, the occurrence of shock waves, interaction of the shock and the boundary layer, thickening of the boundary layer and separation are some challenges which can severely affect the aerodynamic performance. Here we use a numerical analysis and an optimization algorithm to optimize the aerodynamic shape of a transonic axial compressor blade section. The total pressure loss through a cascade of blade sections is selected as the cost function. A continuous adjoint optimization method is used along with a RANS solver to find the new blade section shape. Application of three different geometric modelling of a compressor blade section...

Fault-Tolerant control of uncertain linear systems in the presence of L∞ disturbances and actuator saturation

, Article 4th International Conference on Control, Instrumentation, and Automation, 27 January 2016 through 28 January 2016 ; 2016 , Pages 307-312 ; 9781467387040 (ISBN) Khatibi, M ; Haeri, M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2016

Abstract

In this paper the fault-Tolerant control problem for uncertain linear systems in the presence of L, disturbances and actuator saturation is studied. The conflict between enlarging the domain of attraction and attenuating the effect of L, disturbances is tackled by proposing a non-constant state feedback controller. The feedback gains are calculated off-line by using linear matrix inequalities. In addition, the proposed method is capable of tolerating time-varying faults. The suggested approach is implemented on a sample model and the result is compared with other works

Fault-tolerant control considering time-varying bounds on faults

, Article Transactions of the Institute of Measurement and Control ; Volume 40, Issue 10 , 2018 , Pages 2982-2990 ; 01423312 (ISSN) Khatibi, M ; Haeri, M ; Sharif University of Technology

SAGE Publications Ltd 2018

Abstract

This paper presents a novel fault-tolerant control strategy to compensate the time-varying loss of actuators’ effectiveness. It considers intermediate situations where the fault is not determined precisely (unlike active approaches) but overall estimations about its rate and final value are available through the previous experiences and/or experiments. Based on the estimations, two upper and lower time-varying bounds on the actuators’ effectiveness are established to be exploited in the procedure of controller design. In a special case, where these bounds are constant, the method will be reduced to the conventional passive approach. Also, actuator saturation and the effects of (Formula...

A unified framework for passive–active fault-tolerant control systems considering actuator saturation and L ∞ disturbances

, Article International Journal of Control ; Volume 92, Issue 3 , 2019 , Pages 653-663 ; 00207179 (ISSN) Khatibi, M ; Haeri, M ; Sharif University of Technology

Taylor and Francis Ltd 2019

Abstract

This paper presents a unified passive–active fault-tolerant control strategy to compensate the loss of actuators’ effectiveness. The proposed approach is capable of handling the system in pre- and post-fault diagnosis intervals by passive and active approaches, respectively. The stability of the designed system is independent of the accuracy of information provided by the fault detection and diagnosis unit, however, a precise estimation could improve the conservation. Actuator saturation and L ∞ disturbances effects are considered in the design stage. The trade-off between maximising the domain of attraction and minimising the effects of L ∞ disturbances is tackled by developing a...

A unified framework for passive–active fault-tolerant control systems considering actuator saturation and L∞ disturbances

, Article International Journal of Control ; 2017 , Pages 1-11 ; 00207179 (ISSN) Khatibi, M ; Haeri, M ; Sharif University of Technology

2017

Abstract

This paper presents a unified passive–active fault-tolerant control strategy to compensate the loss of actuators’ effectiveness. The proposed approach is capable of handling the system in pre- and post-fault diagnosis intervals by passive and active approaches, respectively. The stability of the designed system is independent of the accuracy of information provided by the fault detection and diagnosis unit, however, a precise estimation could improve the conservation. Actuator saturation and L∞ disturbances effects are considered in the design stage. The trade-off between maximising the domain of attraction and minimising the effects of L∞ disturbances is tackled by developing a non-constant...

Fault Tolerant Control Considering Actuator Saturation and External Disturbances

, Ph.D. Dissertation Sharif University of Technology Khatibi, Mahmood (Author) ; Haeri, Mohammad (Supervisor)

Abstract

A control system capable of tolerating system malfunctions while maintaining an acceptable level of performance is referred as fault tolerant control system. The constraints on the amplitude of input control signals limit the domain of attraction even for linear models. Ignoring this fact may lead to an unsatisfactory performance and even closed loop instability. Designing the controller such that the domain of attraction is maximized has been an attractive topic for researchers. On the other hand, persistent disturbances always play an essential role in the real word systems. Designing the controller in a way such that the effect of such disturbances is attenuated is another challenging...

Development of Regional Rainfall-Runoff Models

, M.Sc. Thesis Sharif University of Technology Khatibi, Sahar (Author) ; Abrishamchi, Ahmad (Supervisor)

Abstract

Hydrological models are suitable tools for reduction of hydrological uncertainty in stream flow estimation. There are different historical approaches for the development of rainfall-runoff models, with regard to the choice of model structure and the calibration of the parameters, but the most attention has been focused on gauged catchments where sufficient data, in particular stream flow data, are available. So new modeling strategies for ungauged or pseudo ungauged catchments have been developed. This work was aimed to develop a methodology for the regionalization of some parameters of a conceptual rainfall-runoff model based on measurable physiographic, meteorological and even land...

Boundary-induced coherence in the staggered quantum walk on different topologies

, Article Physical Review A ; Volume 98, Issue 1 , July , 2018 ; 24699926 (ISSN) Khatibi Moqadam, J ; Tayefeh Rezakhani, A ; Sharif University of Technology

American Physical Society 2018

Abstract

The staggered quantum walk is a type of discrete-time quantum-walk model without a coin which can be generated on a graph using particular partitions of the graph nodes. We design Hamiltonians for potential realization of the staggered dynamics on a two-dimensional lattice composed of superconducting microwave resonators connected with tunable couplings. The naive generalization of the one-dimensional staggered dynamics generates two uncoupled one-dimensional quantum walks; thus more complex partitions need to be employed. However, by analyzing the coherence of the dynamics, we show that the quantumness of the evolution corresponding to two independent one-dimensional quantum walks can be...

Biodiesel production via transesterification of canola oil in the presence of Na–K doped CaO derived from calcined eggshell

, Article Renewable Energy ; Volume 163 , 2021 , Pages 1626-1636 ; 09601481 (ISSN) Khatibi, M ; Khorasheh, F ; Larimi, A ; Sharif University of Technology

Elsevier Ltd 2021

Abstract

CaO derived from calcined eggshell was doped with Na–K by wet impregnation method and the effect of different Na/K molar ratios was investigated on biodiesel production from canola oil. The catalysts were characterized by X-ray Powder Diffraction (XRD), Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and Thermogravimetric (TGA) analyses. FAME yields were determined by Gas Chromatography-Mass Spectrometry (GC-MS). The Na–K/CaO catalyst with Na/K molar ratio of 1 showed the highest FAME yield of 97.6% at optimum reaction conditions. Structural investigation of materials revealed that FAME yield was proportional to the number of basic sites on...

Mimicking the Hadamard discrete-time quantum walk with a time-independent Hamiltonian

, Article Quantum Information Processing ; Volume 18, Issue 5 , 2019 ; 15700755 (ISSN) Khatibi Moqadam, J ; de Oliveira, M. C ; Sharif University of Technology

Springer New York LLC 2019

Abstract

The discrete-time quantum walk dynamics can be generated by a time-dependent Hamiltonian, repeatedly switching between the coin and the shift generators. We change the model and consider the case where the Hamiltonian is time-independent, including both the coin and the shift terms in all times. The eigenvalues and the related Bloch vectors for the time-independent Hamiltonian are then compared with the corresponding quantities for the effective Hamiltonian generating the quantum walk dynamics. Restricted to the non-localized initial quantum walk states, we optimize the parameters in the time-independent Hamiltonian such that it generates a dynamics similar to the Hadamard quantum walk. We...

Inverse design of supersonic diffuser with flexible walls using a Genetic Algorithm

, Article Journal of Fluids and Structures ; Volume 22, Issue 4 , 2006 , Pages 529-540 ; 08899746 (ISSN) Ziaei-Rad, S ; Ziaei-Rad, M ; Sharif University of Technology

2006

Abstract

An efficient algorithm for the design optimization of the compressible fluid flow problem through a flexible structure is presented. The methodology has three essential parts: first the behavior of compressible flow in a supersonic diffuser was studied numerically in quasi-one-dimensional form using a flux splitting method. Second, a fully coupled sequential iterative procedure was used to solve the steady state aeroelastic problem of a flexible wall diffuser. Finally, a robust Genetic Algorithm was implemented and used to calculate the optimum shape of the flexible wall diffuser for a prescribed pressure distribution. © 2006 Elsevier Ltd. All rights reserved

Production of Biodiesel Using Eggshell as Catalyst

, M.Sc. Thesis Sharif University of Technology Khatibi, Maryam (Author) ; Khorasheh, Farhad (Supervisor) ; Larimi, Afsaneh Sadat (Supervisor)

Abstract

The aim of this project is to investigate and synthesize CaO-based nanocatalysts derived from chicken eggshell calcination with alkali metals and sodium-potassium compounds promoters used in the transesterification reaction of canola oil and methanol. Sections of this thesis include the synthesis of nanocatalysts, catalyst characterization tests, and investigation of reaction under optimal conditions. Two groups of catalysts containing different weight percentages of alkali metals based on CaO and 1 %wt sodium-potassium based on CaO with different weight percentages of these two elements were synthesized by wet impregnation method and used in the reaction under optimum condition. Catalyst...

Generation of transfer functions of subsystems using the test results of the whole system

, Article Conference Proceedings of the Society for Experimental Mechanics Series, 9 February 2009 through 12 February 2009 ; 2009 ; 21915644 (ISSN) ; 9781605609614 (ISBN) Saadat Foumani, M ; Albooyeh, A. R ; Ashory, M. R ; Khatibi, M. M ; Sharif University of Technology

2009

Abstract

This paper presents a new experimental-numerical method for deriving the transfer functions of a half-automobile model, containing: chassis, body, engine, engine mount and steering wheel, with five degrees of freedom. In this method different parts of system are not required to be disassembled from the main system and the transfer functions of subsystem are obtained through testing of the whole system. This method is based on the experimental results and does not need a mathematical model of the half-automobile. In this method, transfer functions of various parts of chassis are calculated through obtaining the response of secondary elements mounted on the chassis to the displacement input...

Automatic image annotation by a loosely joint non-negative matrix factorisation

, Article IET Computer Vision ; Volume 9, Issue 6 , November , 2015 , Pages 806-813 ; 17519632 (ISSN) Rad, R ; Jamzad, M ; Sharif University of Technology

Institution of Engineering and Technology 2015

Abstract

Nowadays, the number of digital images has increased so that the management of this volume of data needs an efficient system for browsing, categorising and searching. Automatic image annotation is designed for assigning tags to images for more accurate retrieval. Non-negative matrix factorisation (NMF) is a traditional machine learning technique for decomposing a matrix into a set of basis and coefficients under the non-negative constraints. In this study, the authors propose a two-step algorithm for designing an automatic image annotation system that employs the NMF framework for its first step and a variant of K-nearest neighbourhood as its second step. In the first step, a new multimodal...

A risk-based MILP approach for optimal placement of flammable gas detectors

, Article Chemical Engineering Transactions ; Volume 53 , 2016 , Pages 145-150 ; 22839216 (ISSN) Rad, A ; Rashtchian, D ; Sharif University of Technology

Italian Association of Chemical Engineering - AIDIC 2016

Abstract

Gas detectors play an important role in safety of process plants. In-time detection of flammable gas releases may prevent major fire and explosion as well as property loss in process plants. One of the challenges of the gas detection system design is determining the best layout for detectors in order to reduce the risk of gas releases as much as possible. However, current methods do not address the risk concept in placement of detectors quantitatively. A risk-based methodology is proposed for optimal placement of point type flammable gas detectors in which first the risk (defined as a combination of scenario frequency, delayed ignition probability and damage) is estimated for any release...

A multi-view-group non-negative matrix factorization approach for automatic image annotation

, Article Multimedia Tools and Applications ; 2017 , Pages 1-21 ; 13807501 (ISSN) Rad, R ; Jamzad, M ; Sharif University of Technology

2017

Abstract

In automatic image annotation (AIA) different features describe images from different aspects or views. Part of information embedded in some views is common for all views, while other parts are individual and specific. In this paper, we present the Mvg-NMF approach, a multi-view-group non-negative matrix factorization (NMF) method for an AIA system which considers both common and individual factors. The NMF framework discovers a latent space by decomposing data into a set of non-negative basis vectors and coefficients. The views divided into homogeneous groups and latent spaces are extracted for each group. After mapping the test images into these spaces, a unified distance matrix is...

A multi-view-group non-negative matrix factorization approach for automatic image annotation

, Article Multimedia Tools and Applications ; Volume 77, Issue 13 , 2018 , Pages 17109-17129 ; 13807501 (ISSN) Rad, R ; Jamzad, M ; Sharif University of Technology

Springer New York LLC 2018

Abstract

In automatic image annotation (AIA) different features describe images from different aspects or views. Part of information embedded in some views is common for all views, while other parts are individual and specific. In this paper, we present the Mvg-NMF approach, a multi-view-group non-negative matrix factorization (NMF) method for an AIA system which considers both common and individual factors. The NMF framework discovers a latent space by decomposing data into a set of non-negative basis vectors and coefficients. The views divided into homogeneous groups and latent spaces are extracted for each group. After mapping the test images into these spaces, a unified distance matrix is...

Image annotation using multi-view non-negative matrix factorization with different number of basis vectors

, Article Journal of Visual Communication and Image Representation ; Volume 46 , 2017 , Pages 1-12 ; 10473203 (ISSN) Rad, R ; Jamzad, M ; Sharif University of Technology

Academic Press Inc 2017

Abstract

Automatic Image Annotation (AIA) helps image retrieval systems by predicting tags for images. In this paper, we propose an AIA system using Non-negative Matrix Factorization (NMF) framework. The NMF framework discovers a latent space, by factorizing data into a set of non-negative basis and coefficients. To model the images, multiple features are extracted, each one represents images from a specific view. We use multi-view graph regularization NMF and allow NMF to choose a different number of basis vectors for each view. For tag prediction, each test image is mapped onto the multiple latent spaces. The distances of images in these spaces are used to form a unified distance matrix. The...

Real time classification and tracking of multiple vehicles in highways

, Article Pattern Recognition Letters ; Volume 26, Issue 10 , 2005 , Pages 1597-1607 ; 01678655 (ISSN) Rad, R ; Jamzad, M ; Sharif University of Technology

2005

Abstract

Real time road traffic monitoring is one of the challenging problems in machine vision, especially when one is using commercially available PCs as the main processor. In this paper, we describe a real-time method for extracting a few traffic parameters in highways such as, lane change detection, vehicle classification and vehicle counting. In addition, we will explain a real time method for multiple vehicles tracking that has the capability of occlusion detection. Our tracing algorithm uses Kalman filter and background differencing techniques. We used morphological operations for vehicle contour extraction and its recognition. Our algorithm has three phases, detection of pixels on moving...

Modelling and Simulation of Melanoma Cancer, Based on Cellular Automata Approaches

, M.Sc. Thesis Sharif University of Technology Rad, Jaber (Author) ; Habibi, Jafar (Supervisor)

Abstract

Nowadays, M&S is critical as a powerful tool for human to fight against cancer. Skin cancer is one of the most widespread cancers and melanoma would be the most dangerous kind of it. In cancerous micro-environment, cancer cells interact with vasculature, and compete with normal cells over nutrients. This plays a major role in tumor progression pattern and speed. In recent years, a few multiscale models have been developed considering these phenomena. Such a model provides a platform for future researches, especially in drug effects prediction. A reliable simulation must satisfy the constraints and facts in the real world as much as possible. M&S credibility assessment is a major concern to...