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    Erratum to: "Fast design of relatively wide band fractional delay all-pass filters" [Signal Process. 88 (3) (2008) 612-623] (DOI:10.1016/j.sigpro.2007.09.006)

    , Article Signal Processing ; Volume 88, Issue 4 , 2008 , Pages 1082- ; 01651684 (ISSN) Jahani Yekta, M. M ; Sharif University of Technology
    2008
    Abstract
    A fast and simple procedure for designing relatively wide band fractional delay (FD) all-pass filters is proposed and filters designed based on it are compared to those designed using Thiran’s method, which is one of the simplest, fastest and widely used approaches in designing FD all-pass filters. It is shown that filters designed using the introduced method have wider fractional group delay (fgpd) bandwidths compared to those obtained via Thiran’s technique, as well as some other desired properties. The designed filters are also demonstrated to be stable for several pairs of filter orders and fgpd values. r2007 Elsevier B.V. All rights reserved  

    Fast design of relatively wide band fractional delay all-pass filters

    , Article Signal Processing ; Volume 88, Issue 3 , 2008 , Pages 612-623 ; 01651684 (ISSN) Jahani Yekta, M. M ; Sharif University of Technology
    Elsevier  2008
    Abstract
    A fast and simple procedure for designing relatively wide band fractional delay (FD) all-pass filters is proposed and filters designed based on it are compared to those designed using Thiran's method, which is one of the simplest, fastest and widely used approaches in designing FD all-pass filters. It is shown that filters designed using the introduced method have wider fractional group delay (fgpd) bandwidths compared to those obtained via Thiran's technique, as well as some other desired properties. The designed filters are also demonstrated to be stable for several pairs of filter orders and fgpd values. © 2007 Elsevier B.V. All rights reserved  

    A compact microstrip combline filter for microwave S-band

    , Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 891-894 ; 9781665433655 (ISBN) Rezaee, S ; Memarian, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    In this paper, a wideband coupled-resonator microstrip bandpass filter is designed and experimentally demonstrated in the S-Band. The filter is comprised of quarter-wavelength hair-pin resonators, reducing resonator and filter footprint compared to conventional hairpin designs. Additionally, it is considerably forgiving to fabrication tolerances and yields remarkably close matched results between theory, simulation, and measured results. One demonstration presented has minimal insertion loss ${(< 1{dB})}$ for the entire wide bandwidth of 3.4 GHz to 4.2 GHz. Wider bandwidths up to 60% are also observed using the design. The proposed filter is an attractive solution when space is a critical... 

    , Ph.D. Dissertation Sharif University of Technology Jahanghiri Yekta, Mohammad Mahdi (Author) ; Behnia, Fereidoun (Supervisor)

    Time-varying assessment of heart rate variability parameters using respiratory information

    , Article Computers in Biology and Medicine ; Volume 89 , 2017 , Pages 355-367 ; 00104825 (ISSN) Goldoozian, L. S ; Zahedi, E ; Zarzoso, V ; Sharif University of Technology
    Abstract
    Analysis of heart rate variability (HRV) is commonly used for characterization of autonomic nervous system. As high frequency (HF, known as the respiratory-related) component of HR, overlaps with the typical low frequency (LF) band when the respiratory rate is low, a reference signal for HF variations would help in better discriminating the LF and HF components of HR. The present study proposes a model for time-varying separation of HRV components as well as estimation of HRV parameters using respiration information. An autoregressive moving average with exogenous input (ARMAX) model of HRV is considered with a parametrically modeled respiration signal as the input. The model parameters are... 

    An algorithm to estimate parameters and states of a nonlinear maneuvering target

    , Article Cogent Engineering ; Volume 7, Issue 1 , 2020 Hosseini, S. N ; Haeri, M ; Khaloozadeh, H ; Sharif University of Technology
    Cogent OA  2020
    Abstract
    This paper investigates the problem of unknown input estimation such as acceleration, target class, and maneuvering target tracking using a hybrid algorithm. One of the challenges of unknown input estimation is that no effective method has been presented so far that could be applied to general cases. The available methods are ineffective when the range of variation of the unknown input parameter is large. Also, the issue of determining the system class could improve the performance of the tracking algorithms in many applications. Using the Bayesian theory, the posterior distribution functions of state and parameter could be obtained concurrently. In the proposed algorithm, Liu and West and... 

    An adaptive unscented Kalman filter for quaternion-based orientation estimation in low-cost AHRS

    , Article Aircraft Engineering and Aerospace Technology ; 2007 , Pages 485-493 ; 00022667 (ISSN) ; Volume 79, Issue 5 Pourtakdoust, S. H ; Ghanbarpour Asl, H ; Sharif University of Technology
    2007
    Abstract
    Purpose - This paper aims to develop an adaptive unscented Kalman filter (AUKF) formulation for orientation estimation of aircraft and UAV utilizing low-cost attitude and heading reference systems (AHRS). Design/methodology/approach - A recursive least-square algorithm with exponential age weighting in time is utilized for estimation of the unknown inputs. The proposed AUKF tunes its measurement covariance to yield optimal performance. Owing to nonlinear nature of the dynamic model as well as the measurement equations, an unscented Kalman filter (UKF) is chosen against the extended Kalman filter, due to its better performance characteristics. The unscented transformation of the UKF is shown... 

    General theory of translation invariant systems [electronic resource]

    , Article Mathematics and Its Applications ; Volume 329, 1995, pp 77-89 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    The basic goal of this article is to present an abstract system-theoretic approach to morphological filtering and the theory of translation invariant systems which is mainly based on residuated semigroups. Some new results as well as a number of basic questions are also introduced  

    Reduction of oscillations via fractional order pre-filtering

    , Article Signal Processing ; Volume 107 , February , 2014 , Pages 407–414 ; ISSN: 01651684 Tavazoei, M. S ; Sharif University of Technology
    Abstract
    In this paper, an effective way is proposed for reduction of oscillations in the response of dynamical systems. In this regard, it is analytically shown that the undesirable oscillations in the response of dynamical systems can be reduced using a simple input shaping fractional order filter. The effectiveness of the proposed fractional calculus based technique is numerically verified in reduction of oscillations in a mass-spring-damper system, a low-pass Chebyshev filter, and a PI-controlled two-mass drive system  

    A method for noise reduction in active-rc circuits

    , Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 58, Issue 12 , 2011 , Pages 906-910 ; 15497747 (ISSN) Gharibdoust, K ; Bakhtiar, M. S ; Sharif University of Technology
    Abstract
    A method for noise reduction in active-$RC$ circuits is introduced. It is shown that the output noise in an active-$RC$ circuit can be considerably reduced, without disturbing the circuit transfer function by inserting appropriate passive or active components in the circuit. The inserted components introduce new signal paths in the circuit for noise reduction while the original circuit transfer function is kept unchanged. The procedure to define the proper paths in the circuit and their transfer functions is given. The effectiveness of the presented method is demonstrated using a second-order active-RC filter fabricated in a 0.18-$ {m}$ CMOS technology  

    A failure analysis study on the fractured connecting bolts of a filter press

    , Article Case Studies in Engineering Failure Analysis ; Volume 4 , 2015 , Pages 26-38 ; 22132902 (ISSN) Molaei, S ; Alizadeh, R ; Attarian, M ; Jaferian, Y ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    The purpose of this study was to investigate the main causes of the co-fracture of sixteen connecting bolts of a filter press cylinder-piston system. Stress state of the bolts during the service conditions has been analyzed and the failure reasons were determined from the fractography analysis and gathered information. According to the obtained results, it was concluded that the bolts had failed by the fatigue mechanism. It seems that insufficient torque was used during assembly  

    Mixed analog-digital crossbar-based hardware implementation of sign-sign LMS adaptive filter

    , Article Analog Integrated Circuits and Signal Processing ; 2010 , Pages 1-8 ; 09251030 (ISSN) Merrikh Bayat, F ; Bagheri Shouraki, S ; Sharif University of Technology
    2010
    Abstract
    Recently announcement of a physical realization of a fundamental circuit element called memristor by researchers at Hewlett Packard (HP) has attracted so much interest worldwide. Combination of this newly found element with crossbar interconnect technology, opened a new field in designing configurable or programmable electronic systems which can have applications in signal processing and artificial intelligence. In this paper, based on the simple memristor crossbar structure, we will propose a new mixed analog-digital circuit as a hardware implementation of the sign-sign least mean square (LMS) adaptive filter algorithm. In this proposed hardware, any multiplication and addition is performed... 

    Mean-square performance analysis of the family of selective partial update and selective regressor affine projection algorithms

    , Article Signal Processing ; Volume 90, Issue 1 , 2010 , Pages 197-206 ; 01651684 (ISSN) Esfand Abadi, M. S ; Palangi, H ; Sharif University of Technology
    2010
    Abstract
    In this paper we present a general formalism for the establishment and mean-square performance analysis of the family of selective partial update affine projection (SPU-AP), selective regressor affine projection (SR-AP), and selective partial update subband adaptive filter (SPU-SAF) algorithms. This analysis is based on energy conservation arguments and does not need to assume a Gaussian or white distribution for the regressors. We demonstrate through simulations that the results are useful in predicting the performance of these adaptive filter algorithms  

    A novel three-phase magnitude-phase-locked loop system

    , Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 53, Issue 8 , 2006 , Pages 1792-1802 ; 10577122 (ISSN) Karimi Ghartemani, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2006
    Abstract
    A novel three-phase magnitude-phase-locked-loop system (3MPLL) for use in the general area of three-phase (power, energy and power electronic) systems is introduced. The proposed 3MPLL suppresses the noise and distortion from the input signal, mitigates the unbalance, and synthesizes the instantaneous positive-sequence component of the input signal; thus it operates as a nonlinear adaptive notch (or band-pass) filter. The 3MPLL also adaptively tracks and estimates the magnitude, phase angle, and frequency of the input signal; thus, its operation as a nonlinear state estimator. Characteristics of the 3MPLL including its mathematical equations as well as steady-state and dynamic responses are... 

    Improving the performance of spatial domain image watermarking with high boost filter

    , Article Indian Journal of Science and Technology ; Vol. 7, issue. 12 , Dec , 2014 , p. 2133-2139 Alirezanejad, M ; Amirgholipour, S ; Safari, V ; Aslani, S ; Arab, M ; Sharif University of Technology
    Abstract
    Authenticating in transaction of digital media becomes an active research field now a day. That is emerging due to the illegal use of digital media and hacking by unauthorized users. Spatial domain based watermarking methods are one of the authentication methods. These methods are not generally robust against intentional or unintentional changes in the images. In this paper, a new method is proposed to recover watermark more precisely in the spatial domain watermarking method. A high-boost filtering is utilized before executing watermark extraction procedure. The watermark information is magnified by preforming this filter. Effectiveness of this filter is proved by several experiment.... 

    Adaptive filtering techniques in passive radar

    , Article Proceedings International Radar Symposium, Dresden ; Volume 2 , June , 2013 , Pages 1067-1078 ; 21555753 (ISSN) ; 9783954042234 (ISBN) Chitgarha, M. M ; Radmard, M ; Majd, M. N ; Nayebi, M. M ; Sharif University of Technology
    2013
    Abstract
    One of the most important obstacles in passive radar applications is removing the direct signal from the target channel. Otherwise, week echoes from the targets in the target channel would be ignored due to the limited dynamic range of the system. One of the most effective techniques in this field is using adaptive filters. In this paper various adaptive filters are introduced and their performances are shown and compared  

    Noise reduction using multi-channel FIR warped wiener filter

    , Article 13th International Multi-Conference on Systems, Signals and Devices, SSD 2016, 21 March 2016 through 24 March 2016 ; 2016 , Pages 531-536 ; 9781509012916 (ISBN) Shamsa, A ; Ghorshi, S ; Joorabchi, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    Abstract
    Enhancing the speech quality is the aim of noise reduction techniques. In order to have a desirable speech signal, it is necessary to eliminate the hearing fatigue and enhance the quality and intelligibility of speech signal. The present of additive noise causes the signal to degrade where the noise reduction techniques intend to remove the effect of noise on speech signals. However, removing the noise should not harm the speech signal when the signal is going to be heard. In this regard, Wiener filter can be used to promote the quality and intelligibility of the noisy signals. This paper explores the performance of multi-channel Wiener filter accompanied by Warped FIR filter  

    Chaos synchronization in noisy environment using nonlinear filtering and sliding mode control

    , Article Chaos, Solitons and Fractals ; Volume 36, Issue 5 , 2008 , Pages 1295-1304 ; 09600779 (ISSN) Behzad, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    2008
    Abstract
    This paper presents an algorithm for synchronizing two different chaotic systems, using a combination of the extended Kalman filter and the sliding mode controller. It is assumed that the drive chaotic system has a random excitation with a stochastically chaotic behavior. Two different cases are considered in this study. At first it is assumed that all state variables of the drive system are available, i.e. complete state measurement, and a sliding mode controller is designed for synchronization. For the second case, it is assumed that the output of the drive system does not contain the whole state variables of the drive system, and it is also affected by some random noise. By combination of... 

    Fast and accurate method for PCL radar detection in noisy environment

    , Article 3rd European Radar Conference, EuRAD 2006, Manchester, 13 September 2006 through 15 September 2006 ; 2006 , Pages 33-36 ; 2960055179 (ISBN); 9782960055177 (ISBN) Mousavi, M. R ; Jafargholi, A ; Nayebi, M. M ; Sharif University of Technology
    IEEE Computer Society  2006
    Abstract
    A new fast and very accurate method for target detection in PCL radars is presented. This algorithm in noisy environment with SNR up to -60dB could provide the perfect and accurate detection. Presented initiative algorithm apply a special filter bank to the target signal and clean the additive noise of the environment from it and detect the multiple targets with different RCSs. © 2006 EuMA  

    Extended and Unscented Kalman filters for parameter estimation of an autonomous underwater vehicle

    , Article Ocean Engineering ; Vol. 91, issue , 2014 , p. 329-339 Sabet, M. T ; Sarhadi, P ; Zarini, M ; Sharif University of Technology
    Abstract
    In this paper, a high performance procedure for estimating of hydrodynamic coefficients in Autonomous Underwater Vehicles (AUV's) is proposed. In modeling of an AUV, experimental data should be verified and validated using appropriate techniques. Due to implementation complexity in calculating methods, computation of hydrodynamic parameters is challenging. This paper presents analytical approaches for estimating an AUV's hydrodynamic coefficients. Nonlinear Kalman Filter (KF) algorithms are implemented to estimate unknown augmented states (coefficients). A comparative study is conducted which shows the superior performance of Unscented Kalman Filter (UKF) in comparison with Extended Kalman...