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A data collection scheme for reliability evaluation and assessment - A practical case in Iran
, Article 2004 International Conference on Power System Technology, POWERCON 2004, 21 November 2004 through 24 November 2004 ; Volume 2 , 2004 , Pages 999-1004 ; 0780386108 (ISBN) ; Fotuhi Friuzabad, M ; Gharahgozloo, H ; Sharif University of Technology
2004
Abstract
Data collection is an essential element of reliability assessment and many utilities throughout the world have established comprehensive procedures for assessing the performance of their electric power systems. Data collection is also a constituent part of quantitative power system reliability assessment in which system past performance and prediction of future performance are evaluated. This paper presents an overview of the Iran electric power system data collection scheme and the procedure to its reliability analysis. The scheme contains both equipment reliability data collection procedure and structure of reliability assessment. The former constitutes generation, transmission and...
System Identification by Image Processing
, M.Sc. Thesis Sharif University of Technology ; Moghaddam, Hassan (Supervisor)
Abstract
Digital image processing techniques are widely used in many areas of research and application such as astronomic monitoring, medical diagnosis, product quality control and weather forecasting. The captured film by camera, is converted into displacement data by using Matlab software and image processing methods. This study intends to provide “proof-of-concept” for the techniques, applying them to identification problems involving the simple pendulum, pendulum in-water, the car suspension system. Studies further illustrate that the digital imaging procedure and algorithms developed for the simple problems can be extended for identification of modal properties and structural characteristics....
The largest studentized residual test for bad data identification in state estimation of a power system
, Article ARPN Journal of Engineering and Applied Sciences ; Volume 10, Issue 21 , NOVEMBER , 2015 , Pages 10184-10191 ; 18196608 (ISSN) ; Radzuan Razali, B ; Daud, H ; Nor, N. M ; Fotuhi Firuzabad, M ; Sharif University of Technology
Asian Research Publishing Network
2015
Abstract
Power system state estimation is a reliable tool used in Energy Management System (EMS) to identify the existence state of the system during its operating hours. The results of this estimation are values for unknown state parameters of the power system. The presence of systematic errors can alter the results of state estimation. The chi-square and normalized residual tests are the common post estimation procedures usually used for detection and identification of gross errors in the estimation algorithm. These tests are based on two separate test statistics and are not so powerful for detection of smaller magnitudes of gross errors. In this paper, an implementation of largest studentized...
Direct controller order reduction by identification in closed loop
, Article Automatica ; Volume 37, Issue 11 , 2001 , Pages 1689-1702 ; 00051098 (ISSN) ; Karimi, A ; Constantinescu, A ; Sharif University of Technology
2001
Abstract
The paper addresses the problem of directly estimating the parameters of a reduced order digital controller using a closed loop type identification algorithm. The algorithm minimizes the closed loop plant input error between the nominal closed loop system and the closed loop system using the reduced order controller. It is assumed that a plant model (if necessary validated in closed loop with the nominal controller) is available. One of the original features of this approach is that it can use either simulated or real data. The frequency bias distribution of the parameter estimates shows that the reduced order controller maintains the critical performance of the nominal closed loop system. A...
Effects of the design parameters of multimodel adaptive control on the performance of a flexible transmission system
, Article International Journal of Adaptive Control and Signal Processing ; Volume 15, Issue 3 , 2001 , Pages 335-352 ; 08906327 (ISSN) ; Landau, I. D ; Motee, N ; Sharif University of Technology
2001
Abstract
Design parameters selection in the multimodel adaptive control based on switching and tuning will be investigated. Some design parameters like number of fixed and adaptive models, forgetting factor and minimum time delay between switchings will be considered. A recently developed parameter adaptation algorithm based on closed-loop output error will be compared with the classical least-squares prediction error algorithm in the multimodel adaptive control. The effects of these parameters on the performance in tracking and in regulation of a flexible transmission system will be studied via several simulation examples
An evolutionary optimizing approach to neural network architecture for improving identification and modeling of aircraft nonlinear dynamics
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Vol. 228, issue. 12 , 2014 , p. 2178-2191 ; Saghafi, F ; Sharif University of Technology
Abstract
In this paper, modified genetic algorithm has been used as a simultaneous optimizer of recurrent neural network to improve identification and modeling of aircraft nonlinear dynamics. Weighted connections, network architecture, and learning rules are features that play important roles in the quality of neural networks training and their generalizability in order to model nonlinear systems. Therefore, the main focus of this paper is to apply appropriate evolutionary methods in order to simultaneously optimize the parameters of neural networks for the improvement identification and modeling of aircraft nonlinear dynamics. To validate this study, the results have been compared with the recorded...
On the identifiability of inertia parameters of planar multi-body space systems
, Article Acta Astronautica ; Volume 145 , April , 2018 , Pages 199-215 ; 00945765 (ISSN) ; Malaek, S. M. B ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This work describes a new formulation to study the identifiability characteristics of Serially Linked Multi-body Space Systems (SLMBSS). The process exploits the so called “Lagrange Formulation” to develop a linear form of Equations of Motion w.r.t the system Inertia Parameters (IPs). Having developed a specific form of regressor matrix, we aim to expedite the identification process. The new approach allows analytical as well as numerical identification and identifiability analysis for different SLMBSSs' configurations. Moreover, the explicit forms of SLMBSSs identifiable parameters are derived by analyzing the identifiability characteristics of the robot. We further show that any SLMBSS...
Experimental parametric identification of a flexible beam using piezoelectric sensors and actuators
, Article Shock and Vibration ; Vol. 2014, Issue. 1 , 2014 ; ISSN: 1070-9622 ; Nobahari, H ; Kordkheili, S. A. H ; Sharif University of Technology
Abstract
Experimental system identification of a flexible beam based on sweep square excitation is studied. For the purpose of nonparametric identification, an excitation signal is conducted to evaluate the frequency response of the system. The experiment is designed to excite the beam using a piezo actuator, in a way to raise the chance of exciting first three natural modes. In order to find the best linear representation of the real system, two different identification methods are applied. First, autoregressive moving average eXogenous method is employed to identify the transfer function of the beam. Then, the identification is carried out using the subspace identification method to obtain the...
The performance comparison of improved continuous mixed P-norm and other adaptive algorithms in sparse system identification
, Article International Journal of Advanced Intelligence Paradigms ; 2020 , Pages 65-74 ; Volume 16, Issue 1 ; Ghaffari, A ; Sharif University of Technology
Inderscience Publishers
2020
Abstract
One of the essential usages of adaptive filters is in sparse system identification on which the performance of classic adaptive filters is not acceptable. There are several algorithms that designed especially for sparse systems; we call them sparsity aware algorithms. In this paper we studied the performance of two newly presented adaptive algorithms in which P-norm constraint is considered in defining cost function. The general title of these algorithms is continuous mixed P-norm (CMPN). The performances of these algorithms are considered for the first time in sparse system identification. Also the performance of l0 norm LMS algorithm is analysed and compared with our proposed algorithms....
Pattern recognition analysis of gas chromatographic and infrared spectroscopic fingerprints of crude oil for source identification
, Article Microchemical Journal ; Volume 153 , 2020 ; Parastar, H ; Sharif University of Technology
Elsevier Inc
2020
Abstract
In this study, a chemometric strategy was developed for analysis of gas chromatographic (GC) and infrared spectroscopic (FT-IR) fingerprints of nine crude oil samples from the main oil wells of Iran to classify them and to find their origins. In this regard, a fractionation method based on saturated, aromatic, resin, and asphaltene (SARA) test was used. Then, these fractions were analyzed by GC-FID and GC–MS. Also, nine crude oil samples were analyzed by FT-IR. The obtained GC fingerprints were aligned using correlation optimized warping (COW) and auto-scaled, and then analyzed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Evaluation of PCA scores plot...
Adaptive input-output linearization control of pH processes
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 27, Issue 3 , 2008 , Pages 25-35 ; 10219986 (ISSN) ; Shahrokhi, M ; Mehrabani, A ; Sharif University of Technology
2008
Abstract
pH control is a challenging problem due to its highly nonlinear nature. In this paper the performances of two different adaptive global linearizing controllers (GLC) are compared. Least squares technique has been used for identifying the titration curve. The first controller is a standard GLC based on material balances of each species. For implementation of this controller a nonlinear state estimator is used. Some modifications are proposed to avoid the singularity of the observer gain. The second controller is designed based on the reduced state equation. Through computer simulations, it has been shown that the performances of the second GLC is superior and it is more robust to process...
Subspace identification of fault modes for a twin-rotor system
, Article International Journal of Intelligent Unmanned Systems ; Volume 9, Issue 4 , 2021 , Pages 313-335 ; 20496427 (ISSN) ; Bintul Huda, A ; Rasool, A ; Bukhari, S. H. R ; Sharif University of Technology
Emerald Group Holdings Ltd
2021
Abstract
Purpose: The purpose of this paper is to identify the fault modes of a nonlinear twin-rotor system (TRS) using the subspace technique to facilitate fault identification, diagnosis and control applications. Design/methodology/approach: For identification of fault modes, three types of system malfunctions are introduced. First malfunction resembles actuator, second internal system dynamics and third represents sensor malfunction or offset. For each fault scenario, the resulting TRS model is applied with persistently exciting inputs and corresponding outputs are recorded. The collected input–output data are invoked in NS4SID subspace system identification algorithm to obtain the unknown fault...
A novel adaptive approach to fingerprint enhancement filter design
, Article Signal Processing: Image Communication ; Volume 17, Issue 10 , 2002 , Pages 849-855 ; 09235965 (ISSN) ; Kasaei, S ; Sharif University of Technology
2002
Abstract
A novel procedure for fingerprint enhancement filter design is described. Fingerprints are best used as unique and invariant identifiers of individuals. Identification of fingerprint images is based on matching the features obtained from a query image against those stored in a database. Poor quality of fingerprint images makes serious problems in the performance of subsequent matching process. The main contribution of this work is to quantify and justify the functional relationship between image features and filter parameters. In this work, the enhancement process is adapted to the input image characteristics to improve its efficiency. Experimental results show the superiority of the...
Improving the Security and Performance of a Ticket-based Single Sign-on Authentication Systems
, M.Sc. Thesis Sharif University of Technology ; Jalili, Rasool (Supervisor)
Abstract
Nowadays, user accounts on websites such as Google, Facebook, and Yahoo are their key to login into other websites and on the Internet. Thus, there is no need for authentication in each website and each user can access his/her other accounts just by logging in Google or Facebook. In background, single sign-on protocols such as OpenID and OAuth are being used. Since single sign-on accounts are very critical and sensitive, they are always under attack of cyber intruders. One of the most important threats is phishing in which one of the seeming trustful components could be attacker.This thesis demonstrates that OpenID providers may not be worthwhile and trustful as they are able to have...
Frequency domain identification of the Nomoto model to facilitate Kalman filter estimation and PID heading control of a patrol vessel
, Article Ocean Engineering ; Volume 72 , November , 2013 , Pages 344-355 ; 00298018 (ISSN) ; Ghorbani, M. T ; Sharif University of Technology
2013
Abstract
This paper presents a detailed frequency-domain system identification method applied to identify steering dynamics of a coastal patrol vessel using a data analysis software called CIFER. Advanced features such as the Chirp-Z transform and composite window optimization are used to extract high quality frequency responses. An accurate, robust and linear transfer function model is derived for yaw and roll dynamics of the vessel. To evaluate the accuracy of the identified model, time domain responses from a 45-45 zig-zag test are compared with the responses predicted by the identified model. The identified model shows excellent predictive capability and is well suited for simulation and...
Blind modal identification of structures from spatially sparse seismic response signals
, Article Structural Control and Health Monitoring ; Vol. 21, issue. 5 , May , 2014 , p. 649-674 ; Abazarsa, F ; Ghannad, M. A ; Celebi, M ; Taciroglu, E ; Sharif University of Technology
Abstract
Response-only identification of civil structureshas attracted much attention during recent years, as input excitations are rarely measurable for ambient vibrations. Although various techniques have been developed by which identification can be carried out using ambient responses, these techniques are generally not applicable to non-stationary excitations that structures experience during moderate-to-severe earthquakes. Recently, the authors proposed a new response-only modal identification method that is applicable to strong shaking data. This new method is highly attractive for cases in which the true input motions are unavailable. For example, when soil-structure interaction effects are...
Object-oriented design for system identification and its application in chemical engineering industries
, Article International Journal of Modelling and Simulation ; Volume 33, Issue 1 , 2013 , Pages 33-39 ; 02286203 (ISSN) ; Boozarjomehry, R. B ; Sharif University of Technology
2013
Abstract
Application of advanced process control methods in a chemical plant requires a model which represents the transient behaviour of the plant. However, only a few plant-wide identification methods have been proposed for chemical processes. In this paper, an objectoriented process identifier (OPI) framework has been introduced for plant-wide identification to show how using object-oriented design can provide a general plant-wide modelling framework for various systems including chemical processes. The interactions between units are considered in plant-wide identification methods. As a result, the obtained models can predict the system behaviour in new operating conditions better than those...
System identification for characterization of the frequency response of an 'open-source' biomedical circuit
, Article IECBES 2014, Conference Proceedings - 2014 IEEE Conference on Biomedical Engineering and Sciences: "Miri, Where Engineering in Medicine and Biology and Humanity Meet", 8 December 2014 through 10 December 2014 ; 2015 , Pages 225-229 ; 9781479940844 (ISBN) ; Mohd Ali, M. A. B ; Sharif University of Technology
Abstract
In this paper, system identification techniques are applied to accurately characterize the frequency behavior of a commercially available but with unknown characteristics of a photoplethysmography (under the commercial name of Pulse Sensor). Although claimed to be open-source, the electronic schematic of this device does not allow for a full characterization of it. Therefore a second order auto-regressive with exogenous input model has been employed to find the frequency response of this system. An optical excitation circuit was developed to send a pseudo-random signal to the Pulse Sensor. Results show that the model is able to reproduce the output with a fitness of 89.7 %. The obtained...
Real-time parameter identification for highly coupled nonlinear systems using Adaptive Particle Swarm Optimization
, Article Mechanika ; Volume 86, Issue 6 , 2010 , Pages 43-49 ; 13921207 (ISSN) ; Nemati, A ; Safavi, A. A ; Sharif University of Technology
Abstract
The In this paper, an Adaptive Particle Swarm Optimization (APSO) method is proposed for parameter identification of highly coupled electromechanical systems. Using some modifications on the APSO, better computational efficiency is achieved. In this way, the speed of real-time identification procedure is improved. In addition, to show the effectiveness of the proposed method, it is implemented on a real ball on plate setup and its dynamic model is achieved. Both the simulation and the experimental results show that parameter identification of the proposed algorithm is significantly improved when compared with other existing identification methods based on the traditional PSO and Genetic...
Modal parameter identification of rotary systems based on power spectral density transmissibility functions
, Article 2018 SAE World Congress Experience, WCX 2018, 10 April 2018 through 12 April 2018 ; Volume 2018-April , 2018 ; 01487191 (ISSN) ; Sharif University of Technology
SAE International
2018
Abstract
Operational modal analysis based on power spectral density transmissibility functions (PSDT) is a powerful tool to identify the modal parameters with low sensitivity to excitations. The rotor systems may have the asymmetric damping or stiffness matrices which can lead to increase the difficulties of the identification procedure. In this paper, a new method is proposed to identify the modal parameters of the asymmetric rotary systems by the operational modal analysis based on the power spectral density transmissibility functions. For pole extraction from the PSDT function, a proper parametric identification method such as the Poly-reference Least Squares Complex Frequency-domain method...