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Fragility and Risk Analysis of Electrical Substation Equipment Using Reliability and Endurance Time Methods
, M.Sc. Thesis Sharif University of Technology ; Esmail Pourestekanchi, Homayoon (Supervisor)
Abstract
Electrical substations and its vital components such as switchgears, have experienced severe damage during recent earthquakes, followed by widespread blackouts around the world. To improve the seismic resiliency of power grids and use probabilistic decision-making frameworks, comprehensive fragility data for the different equipment is needed. The purpose of this study is to assess the vulnerability of equipment in substations and to develop fragility curves for this equipment. For this purpose, four main equipment of switchgear, namely circuit breaker, disconnect switch, current transformer and surge arrester, have been modeled in three dimensions and verified. After examining the different...
A New Procedure for Derivation of Fragility Curve with Endurance Time Method
, M.Sc. Thesis Sharif University of Technology ; Estekanchi, Homayoon (Supervisor) ; Mahsuli, Mojtaba (Supervisor)
Abstract
This project aims at the calculation of response distribution of a structure using Endurance Time Analysis (ETA). The traditional approach for this calculation is Incremental Dynamic Analysis (IDA). One of the drawbacks of the IDA is its excessive computational complexity. In the ETA, the structure is analyzed using a set of artificial ground motions with increasing intensities as time passes. As a result, the ETA can be used to calculate the response distribution of the structure in a range of intensities. In the traditional ETA, only the median of the response is calculated. In this study, the response distribution is calculated as well as the median. To achieve this, the proposed approach...
Multi-Attribute decision making on Inter-Basin Water Transfer projects
, Article Scientia Iranica ; Volume 16, Issue 1 E , 2009 , Pages 73-80 ; 10263098 (ISSN) ; Szidarovszky, F ; Ardakanian, R ; Sharif University of Technology
2009
Abstract
One of the best ways to control water shortages in the central region of Iran is Inter-Basin Water Transfer (IBWT). Efficient decision making on this subject is, however, a real challenge for the water authorities in Iran. These decisions should include multiple attributes, model uncertainty and, also, the optimistic/pessimistic view of the decision makers. The Ordered Weighted Averaging (OWA) operator can be used as an efficient Multi-Attribute Decision Making (MADM) method. This paper will introduce a new method to obtain the order weights of this operator. The new method is based on a combination of fuzzy quantifiers and neat OWA operators. Fuzzy quantifiers are usually applied in soft...
Design of a fractional order PID controller for an AVR using particle swarm optimization
, Article Control Engineering Practice ; Volume 17, Issue 12 , 2009 , Pages 1380-1387 ; 09670661 (ISSN) ; Karimi Ghartemani, M ; Sadati, N ; Parniani, M ; Sharif University of Technology
Abstract
Application of fractional order PID (FOPID) controller to an automatic voltage regulator (AVR) is presented and studied in this paper. An FOPID is a PID whose derivative and integral orders are fractional numbers rather than integers. Design stage of such a controller consists of determining five parameters. This paper employs particle swarm optimization (PSO) algorithm to carry out the aforementioned design procedure. PSO is an advanced search procedure that has proved to have very high efficiency. A novel cost function is defined to facilitate the control strategy over both the time-domain and the frequency-domain specifications. Comparisons are made with a PID controller and it is shown...
Surrogate SDOF models for probabilistic performance assessment of multistory buildings: Methodology and application for steel special moment frames
, Article Engineering Structures ; Volume 212 , 2020 ; Mahsuli, M ; Ghannad, M. A ; Zareian, F ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper proposes a methodology for generating surrogate single-degree-of-freedom (SDOF) models that can be utilized to estimate the probability distribution of the roof drift ratio of multistory buildings at various ground motion intensity measures. The use of an SDOF model as a surrogate for multistory buildings can significantly alleviate the high computational cost for probabilistic seismic demand assessment considering both model uncertainty and record-to-record variability. The surrogate SDOF model generated herein explicitly accounts for model uncertainties and can be used as an alternative to the nonlinear dynamic analysis of detailed building structures. Applications for such...
Zero-gravity emulation of satellites in present of uncalibrated sensors and model uncertainties
, Article Proceedings of the IEEE International Conference on Control Applications, 8 July 2009 through 10 July 2009, Saint Petersburg ; 2009 , Pages 1063-1068 ; 9781424446025 (ISBN) ; Namvar, M ; Sharif University of Technology
Abstract
Recently, an alternative to the standard passive zero gravity emulation testbeds is developed which uses robotic technology. It is comprised of a manipulator whose end-effector rigidly grasps a satellite mock up, a six-axis force/moment (F/M) sensor placed at the interface of the satellite and the manipulator, and a control system. Despite significant advantages of the approach there exist practical problems such as the existence of uncertainty in the robot dynamic model as well as uncalibrated force/moment sensor measurements. In this paper, new adaptive methods based on the Lyapunov theory are proposed to deal with the model uncertainty and imperfect sensor measurements. Simulations which...
Model reference adaptive impedance control of rehabilitation robots in operational space
, Article Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, 24 June 2012 through 27 June 2012 ; June , 2012 , Pages 1698-1703 ; 21551774 (ISSN) ; 9781457711992 (ISBN) ; Behzadipour, S ; Vossoughi, G. R ; Sharif University of Technology
2012
Abstract
A new nonlinear model reference adaptive impedance controller is presented for the control of robot manipulators with uncertainties in model parameters such as friction coefficients. This method provides asymptotic tracking of a reference impedance model for the robot end-effector in operational space which is more sensible for the patient compared to the joint space impedance used in previous works. The model uncertainties such as friction coefficients are compensated using an adaptation law. The asymptotic tracking of the reference impedance model is shown using a Lyapunov function. The tracking performance and friction compensation are also demonstrated through simulation on a...
Nonlinear robust adaptive sliding mode control of influenza epidemic in the presence of uncertainty
, Article Journal of Process Control ; Volume 56 , 2017 , Pages 48-57 ; 09591524 (ISSN) ; Moradi, H ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
In this paper, a nonlinear robust adaptive sliding mode control strategy is presented for the influenza epidemics in the presence of model uncertainties. The nonlinear epidemiological model of influenza with five state variables (the numbers of susceptible, exposed, infected, asymptomatic and recovered individuals) and two control inputs (vaccination and antiviral treatment) is considered. The objective of the proposed controller is decreasing the number of susceptible and infected humans to zero by tracking the desired scenarios. As a result of this decreasing, the number of exposed and asymptomatic individuals is also decreased and converged to the zero. Accordingly, it is shown that the...
Patient-Robot-therapist collaboration using resistive impedance controlled tele-robotic systems subjected to time delays
, Article Journal of Mechanisms and Robotics ; Volume 10, Issue 6 , 2018 ; 19424302 (ISSN) ; Salarieh, H ; Behzadipour, S ; Tavakoli, M ; Sharif University of Technology
Abstract
In this paper, an approach to physical collaboration between a patient and a therapist is proposed using a bilateral impedance control strategy developed for delayed tele-robotic systems. The patient performs a tele-rehabilitation task in a resistive virtual environment with the help of online assistive forces from the therapist being provided through teleoperation. Using this strategy, the patient's involuntary hand tremors can be filtered out and the effort of severely impaired patients can be amplified in order to facilitate their early engagement in physical tasks. The response of the first desired impedance model is tracked by the master robot (interacting with the patient), and the...
Assist-as-needed policy for movement therapy using telerobotics-mediated therapist supervision
, Article Control Engineering Practice ; Volume 101 , 2020 ; Behzadipour, S ; Salarieh, H ; Tavakoli, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this paper, a new impedance-based teleoperation strategy is proposed for assist-as-needed tele-rehabilitation via a multi-DOF telerobotic system having patient–master and therapist–slave interactions. Unlike a regular teleoperation system and as the main contribution of this work to minimize the therapist's movements, the therapist's hand only follows the patient's deviation from the target trajectory. Also it provides a better perception of the patient's problems in motor control to the therapist The admissible deviation of the patient's limb from a reference target trajectory is governed by an impedance model responding to both patient's and therapist's interaction forces. As the other...
Multiple model filters applied to wind model estimation for a fixed wing UAV
, Article Proceedings of 2016 7th International Conference on Mechanical and Aerospace Engineering, ICMAE 2016, 18 July 2016 through 20 July 2016 ; 2016 , Pages 109-115 ; 9781467388290 (ISBN) ; Nobahari, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
The flight of unmanned aerial vehicles is often associated with model uncertainties, measurement noises, and environmental disturbances such as wind gust. To mitigate these challenges, the accurate estimation of states is vital. Moreover, the wind model and its parameters should also be estimated and compensated during the flight. In this paper, a multiple model filter is implemented for this purpose. To investigate the performance of the multiple model filter, three different models including constant wind, '1-cosine' model and wind shear model are considered. The multiple model filter utilizes three extended Kalman filter to simultaneously estimate the model of wind, the parameters of the...
Fuzzy dynamic thermal rating of transmission lines
, Article IEEE Transactions on Power Delivery ; Volume 27, Issue 4 , 2012 , Pages 1885-1892 ; 08858977 (ISSN) ; Fotuhi Firuzabad, M ; Aminifar, F ; Sharif University of Technology
Abstract
Dynamic thermal rating (DTR) of transmission system facilities is a way to maximally realize the equipment capacities while not threatening their health. With regards to transmission lines, the allowable current of conductors is forecasted based on the environmental situations expected in some forthcoming time periods. Due to the fact that weather conditions continuously vary, sampling points are very limited against many line spans, and the measurements have an inherent error, uncertainties must be appropriately included in the DTR determination. This paper adopts the fuzzy theory as a strong and simple tool to model uncertainties in the DTR calculation. Since DTR intends to determine the...
Probabilistic hierarchical bayesian framework for time-domain model updating and robust predictions
, Article Mechanical Systems and Signal Processing ; 2018 ; 08883270 (ISSN) ; Papadimitriou, C ; Katafygiotis, L. S ; Sharif University of Technology
Abstract
A new time-domain hierarchical Bayesian framework is proposed to improve the performance of Bayesian methods in terms of reliability and robustness of estimates particularly for uncertainty quantification and propagation in structural dynamics. The proposed framework provides a reliable approach to account for the variability of the inference results observed when using different data sets. The proposed formulation is compared with a state-of-the-art Bayesian approach using numerical and experimental examples. The results indicate that the hierarchical Bayesian framework provides a more realistic account of the uncertainties, whereas the non-hierarchical Bayesian approach severely...
Probabilistic hierarchical bayesian framework for time-domain model updating and robust predictions
, Article Mechanical Systems and Signal Processing ; Volume 123 , 2019 , Pages 648-673 ; 08883270 (ISSN) ; Papadimitriou, C ; Katafygiotis, L. S ; Sharif University of Technology
Academic Press
2019
Abstract
A new time-domain hierarchical Bayesian framework is proposed to improve the performance of Bayesian methods in terms of reliability and robustness of estimates particularly for uncertainty quantification and propagation in structural dynamics. The proposed framework provides a reliable approach to account for the variability of the inference results observed when using different data sets. The proposed formulation is compared with a state-of-the-art Bayesian approach using numerical and experimental examples. The results indicate that the hierarchical Bayesian framework provides a more realistic account of the uncertainties, whereas the non-hierarchical Bayesian approach severely...
Hierarchical Bayesian operational modal analysis: Theory and computations
, Article Mechanical Systems and Signal Processing ; Volume 140 , 2020 ; Katafygiotis, L. S ; Papadimitriou, C ; Sharif University of Technology
Academic Press
2020
Abstract
This paper presents a hierarchical Bayesian modeling framework for the uncertainty quantification in modal identification of linear dynamical systems using multiple vibration data sets. This novel framework integrates the state-of-the-art Bayesian formulations into a hierarchical setting aiming to capture both the identification precision and the variability prompted due to modeling errors. Such developments have been absent from the modal identification literature, sustained as a long-standing problem at the research spotlight. Central to this framework is a Gaussian hyper probability model, whose mean and covariance matrix are unknown, encapsulating the uncertainty of the modal parameters....
Micro resonator nonlinear dynamics considering intrinsic properties
, Article Scientia Iranica ; Volume 16, Issue 2 B , 2009 , Pages 121-129 ; 10263098 (ISSN) ; Tadayon, M. A ; Eftekharian, A. A ; Sharif University of Technology
2009
Abstract
One of the most important phenomena to affect the motion behaviour of Micro Resonators is their thermal dependency. This has recently received the attention of researchers widely. A thermal phenomenon has two main effects, the first is damping, due to internal friction, and the second is softening, due to Young's modulus-temperature relationship. In this research work, some theoretical and experimental reported results are used to make a proper model, including thermal phenomena. Two Lorentzian functions are used to describe the restoring and damping forces caused by thermal phenomena. In order to emphasize the thermal effects, a nonlinear model of the MEMS, considering capacitor...
Control of stochastic chaos using sliding mode method
, Article Journal of Computational and Applied Mathematics ; Volume 225, Issue 1 , 2009 , Pages 135-145 ; 03770427 (ISSN) ; Alasty, A ; Sharif University of Technology
2009
Abstract
Stabilizing unstable periodic orbits of a deterministic chaotic system which is perturbed by a stochastic process is studied in this paper. The stochastic chaos is modeled by exciting a deterministic chaotic system with a white noise obtained from derivative of a Wiener process which eventually generates an Ito differential equation. It is also assumed that the chaotic system being studied has some model uncertainties which are not random. The sliding mode controller with some modifications is used for stochastic chaos suppression. It is shown that the system states converge to the desired orbit in such a way that the error covariance converges to an arbitrarily small bound around zero. As...
Iterative sparsification-projection: Fast and robust sparse signal approximation
, Article IEEE Transactions on Signal Processing ; Volume 64, Issue 21 , 2016 , Pages 5536-5548 ; 1053587X (ISSN) ; Babaie zadeh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
In this paper, we address recovery of sparse signals from compressed measurements, and sparse signal approximation, which have received considerable attention over the last decade. First, we revisit smoothed L0 (SL0), a well-known sparse recovery algorithm, and give some insights into it that have not been noticed previously. Specifically, we re-derive the SL0 algorithm based on proximal methods, and using recent results in solving nonconvex problems by proximal algorithms, we provide a convergence guarantee for it. In addition, inspired by this derivation, we propose a general family of algorithms, which we call iterative sparsification-projection (ISP), having SL0 as a special member. Our...
Adaptive 2D-path optimization of steerable bevel-tip needles in uncertain model of brain tissue
, Article 2009 WRI World Congress on Computer Science and Information Engineering, CSIE 2009, Los Angeles, CA, 31 March 2009 through 2 April 2009 ; Volume 5 , 2009 , Pages 254-260 ; 9780769535074 (ISBN) ; Torabi, M ; Sharif University of Technology
2009
Abstract
Although there are many works in which path planning of robots is studied, but path planning of the bevel-tip needles with highly flexible body is different and difficult due to unique properties of soft tissues. Real soft tissues are nonhomogeneously elastic and uncertainly deformable and hence, during needle motions the planned path changes unknowingly. In this paper, a novel adaptive path planning of bevel-tip needles inside the uncertain brain tissue is presented. The proposed approach is based on minimization of a Lyapanov energy function used as the cost function which consists of 6 partial costs: path length, number of changes in bevel direction, tissue deformation, horizontal and...
A robust kalman filter-based approach for SoC estimation of lithium-ION batteries in smart homes
, Article Energies ; Volume 15, Issue 10 , 2022 ; 19961073 (ISSN) ; Habibifar, R ; Wang, Z ; Sharif University of Technology
MDPI
2022
Abstract
Battery energy systems are playing significant roles in smart homes, e.g., absorbing the uncertainty of solar energy from root-top photovoltaic, supplying energy during a power outage, and responding to dynamic electricity prices. For the safe and economic operation of batteries, an optimal battery-management system (BMS) is required. One of the most important features of a BMS is state-of-charge (SoC) estimation. This article presents a robust central-difference Kalman filter (CDKF) method for the SoC estimation of on-site lithium-ion batteries in smart homes. The state-space equations of the battery are derived based on the equivalent circuit model. The battery model includes two RC...