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    A fast converging algorithm for network echo cancelation

    , Article IEEE Signal Processing Letters ; Volume 11, Issue 4 , 2004 , Pages 427-430 ; 10709908 (ISSN) Nekuii, M ; Atarodi, M ; Sharif University of Technology
    2004
    Abstract
    This letter presents a novel method for network echo cancelation, based on a combination of normalized least mean square (NLMS) and proportionate NLMS (PNLMS) adaptive filtering algorithms. First, based on a rough analysis of PNLMS adaptation, it is indicated why after PNLMS initial fast convergence, it slows down. Then, the method used to overcome this deficiency is presented. Last, by showing some of the simulations, its improvement over PNLMS algorithm is shown  

    A new adaptive lifting scheme transform for robust object detection

    , Article 2006 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2006, Toulouse, 14 May 2006 through 19 May 2006 ; Volume 2 , 2006 , Pages II749-II752 ; 15206149 (ISSN); 142440469X (ISBN); 9781424404698 (ISBN) Amiri, M ; Rabiee, H. R ; Sharif University of Technology
    2006
    Abstract
    This paper presents a new adaptive lifting scheme transform for detecting user-selected objects in a sequence of images. In our algorithm, we first select a set of object features in the wavelet transform domain and then build an adaptive transform by using the selected features. The adaptive transform is constructed based on adaptive prediction in a lifting scheme procedure. Adaptive prediction is performed such that, the large coefficients in the high-pass component of the non-adaptive transform vanishes in the high-pass component of the adaptive transform. Finally, both the non-adaptive and adaptive transforms are applied to a given test image and the transform domain coefficients are... 

    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  

    Modelling of localized plastic deformation via the adaptive mesh refinement

    , Article International Journal of Nonlinear Sciences and Numerical Simulation ; Volume 4, Issue 1 , 2003 , Pages 31-45 ; 15651339 (ISSN) Khoei, A. R ; Gharehbaghi, S. A ; Sharif University of Technology
    2003
    Abstract
    The capturing of localized plastic deformation in a Finite-element analysis is difficult as discontinuities of displacement occur and these are generally precluded in a standard displacement analysis. In this paper, an adaptive mixed finite element model is presented in the modelling of strain localization due to material instability. An h-adaptive analysis using element elongation is applied to study the prediction of localization phenomenon and evaluate the ultimate capacity of material. A remeshing strategy is employed to compute the distribution of required element size using the estimated error distribution. Once the new element size and its alignment have been indicated, an automated... 

    λ-universe: Introduction and preliminary study

    , Article Advances in Neural Networks and Applications ; 2001 , Pages 140-145 ; 9608052262 (ISBN) Joghataie, A ; Sharif University of Technology
    World Scientific and Engineering Academy and Society  2001
    Abstract
    Interactions between the members of an imaginary universe, where all the members are adaptive and have learning capability, is simulated numerically by using artificial neural networks. The universe is called λ-universe for brevity. It is shown here that in such a universe, rules governing the behavior of the members might be formed inside the universe by its own members and the randomness which is observed in the behavior of its members is a direct result of the learning capability of the members. Although this is not a simulation of the real universe, some fundamental concepts of astrophysics have been implemented in it  

    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) Karimi, A ; 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  

    Comparison of four adaptive PID controllers

    , Article Scientia Iranica ; Volume 6, Issue 5 , 2000 , Pages 129-136 ; 10263098 (ISSN) Shahrokhi, M ; Fanaei, M. A ; Sharif University of Technology
    Sharif University of Technology  2000
    Abstract
    PID controllers have been used for many years in industry and if a controller is well tuned, its performance is acceptable for many industrial processes. When the operating point is changed, due to nonlinear behavior of most processes, the controller should be retuned. In this regard, several self-tuning PID controllers are proposed in the literature. In this paper, four such algorithms are compared through simulation and experimental studies. In the simulation study, the effects of factors such as process pole locations, non-minimum phase behavior and model changes on the performance of the schemes are investigated. Simulation and experimental results demonstrate that one of the schemes... 

    Towards a self-adaptive service-oriented methodology based on extended SOMA

    , Article Frontiers of Information Technology & Electronic Engineering ; Volume 16, Issue 1 , January 2015 , Pages 43-69 Parvizi-Mosaed, A ; Moaven, S ; Habibi, J ; Beigi, G ; Naser-Shariat, M ; Sharif University of Technology
    Abstract
    We propose a self-adaptive process (SAP) that maintains the software architecture quality using the MAPE-K standard model. The proposed process can be plugged into various software development processes and service-oriented methodologies due to its explicitly defined inputs and outputs. To this aim, the proposed SAP is integrated with the service-oriented modeling and application (SOMA) methodology in a two-layered structure to create a novel methodology, named self-adaptive service-oriented architecture methodology (SASOAM), which provides a semi-automatic self-aware method by the composition of architectural tactics. Moreover, the maintenance activity of SOMA is improved using... 

    Some nonlinear/adaptive methods for fast recovery of the missing samples of signals

    , Article Signal Processing ; Volume 88, Issue 3 , 2008 , Pages 624-638 ; 01651684 (ISSN) Ghandi, M ; Jahani Yekta, M. M ; Marvasti, F ; Sharif University of Technology
    2008
    Abstract
    In this paper an iterative method for recovery of the missing samples of signals is investigated in detail, and some novel linear, nonlinear, and adaptive extrapolation techniques are proposed to be used along with it to increase the convergence rate of the recovery system. The proposed methods would remarkably speed up the convergence rate, save processing power, and reduce the delay of the system compared to some well known accelerated versions of the aforementioned iterative algorithm. © 2007 Elsevier B.V. All rights reserved  

    A new object detection algorithm based on adaptive lifting scheme

    , Article IWSSIP 2005 - 12th International Workshop on Systems, Signals and Image Processing(SSIP-SPI, 2005), Chalkida, 22 September 2005 through 24 September 2005 ; 2005 , Pages 133-136 ; 0907776205 (ISBN); 9780907776208 (ISBN) Amiri, M ; Rabiee, H. R ; Sharif University of Technology
    2005
    Abstract
    This paper presents a new algorithm for detecting user-selected objects in a sequence of images based on adaptively lifted wavelet transforms. In our algorithm, we first select a set of object features in the wavelet transform domain and then build a new transform by using the selected features. The new wavelet transform is constructed based on adaptive prediction in a lifting scheme structure. Adaptive prediction is performed such that, the large coefficients in the high-pass component of the old transform, vanish in the high-pass component of the new transform. Finally, both of the old and new transforms are applied to a given test image and the transform domain coefficients are compared... 

    Performance evaluation of fully adaptive routing under different workloads and constant node buffer size

    , Article 11th International Conference on Parallel and Distributed Systems Workshops, ICPADS 2005, Fukuoka, 20 July 2005 through 22 July 2005 ; Volume 2 , 2005 , Pages 510-514 ; 15219097 (ISSN); 0769522815 (ISBN) Rezazad, M ; Sarbazi Azad, H ; Ma J ; Yang L. T ; Sharif University of Technology
    2005
    Abstract
    In this paper, the performance of some popular direct interconnection networks, namely the mesh, torus and hypercube, are studied with adaptive wormhole routing for different traffic patterns. We investigate the effect of the number of virtual channels and depth of their buffers on the performance of such strictly orthogonal topologies under uniform, hot-spot and matrix-transpose traffic patterns for generated messages, while the total buffer size associated to each physical channel is kept constant. In addition we analyze the effect of escape channel buffer length on the performance of a fully adaptive routing algorithm. It is shown that the optimal number of virtual channels and buffer... 

    A service based approach to self-adaptive software systems based on constructing a group of autonomic elements

    , Article Proceedings of the 7th IEEE International Conference and Workshop on Engineering of Autonomic and Autonomous Systems, EASe 2010, 22 March 2010 through 26 March 2010 ; March , 2010 , Pages 101-105 ; 9780769540047 (ISBN) Safi, G ; Mirian Hosseinabadi, S. H ; Sharif University of Technology
    2010
    Abstract
    As requirements and environments become much more complex, the need for self-adaptive and self-healing software system grows. There are several existing works which present such systems by using different approaches. Using alternative solutions to provide a service or requirement is one of the most important approaches among existing works. In this paper an alternative-based approach for adding self-adaptive capabilities to software systems is proposed. In this approach a group of autonomic elements will be constructed based on different design or implementations that could be considered for a specific service or requirement. By using this approach, a highly adaptive software system could be... 

    Computational complexity reduction of an adaptive congestion control in active queue management

    , Article Chinese Control and Decision Conference 2008, CCDC 2008, Yantai, Shandong, 2 July 2008 through 4 July 2008 ; 2008 , Pages 3743-3747 ; 9781424417346 (ISBN) Ostadabbas, S ; Haeri, M ; Sharif University of Technology
    2008
    Abstract
    Active Queue Management (AQM) policies provide an early indication of incipient congestion to the source. In this paper, we propose a new AQM policy that predicts the instantaneous queue length at the next time instant using adaptive filtering technique. To use this algorithm in fast routers, we have reduced its computational complexity. The proposed method uses a simple linear function as adaptive rule. We show that this adaptive congestion control method is able to control the oscillations in the instantaneous queue length. We compare the performance of our method with the other well-known AQM methods such as RED and PI which are also simulated by MATLAB. We also compare the computational... 

    Robust adaptive sliding mode admittance control of exoskeleton rehabilitation robots

    , Article Scientia Iranica ; Volume 25, Issue 5B , 2018 , Pages 2628-2642 ; 10263098 (ISSN) Torabi, M ; Sharifi, M ; Vossoughi, Gh ; Sharif University of Technology
    Sharif University of Technology  2018
    Abstract
    A nonlinear robust adaptive sliding mode admittance controller is proposed for exoskeleton rehabilitation robots. The proposed controller has robustness against uncertainties of dynamic parameters using an adaptation law. Furthermore, an adaptive Sliding Mode Control (SMC) scheme is employed in the control law to provide robustness against disturbances (non-parametric uncertainties) with unknown bounds. For this purpose, another adaptation law is defined for the variation of the SMC gain. The proposed scheme is augmented with an admittance control method to provide the patient with compliance during interaction with the rehabilitation robot. The stability of the proposed controller and the... 

    Indirect adaptive fuzzy sliding mode control of 3D inverted pendulum

    , Article 2017 IEEE 4th International Conference on Knowledge-Based Engineering and Innovation, KBEI 2017 ; Volume 2018-January , 2018 , Pages 0919-0924 ; 9781538626405 (ISBN) Nikzad Goltapeh, A ; Shokouhyan, M. R ; Motekallem, A ; Sharifi, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    In this paper, an indirect adaptive fuzzy sliding mode controller for a 3-dimensional inverted pendulum as a fully actuated MIMO system is developed. This inverted pendulum, has four degrees of freedom and equations of the system are nonlinear and non-minimum phase. Thus, control of this system is a challenging issue. Accordingly, in this work, general basis of sliding mode control method with reaching rules is expressed for this system, then the fuzzy control theory is combined, and modeling uncertainties of the system are estimated by universal fuzzy approximation theory. Controller parameters are updated by a defined adaptation law to decrease the tracking error of the inverted pendulum.... 

    Model reference adaptive control in fractional order systems using discrete-time approximation methods

    , Article Communications in Nonlinear Science and Numerical Simulation ; Volume 25, Issue 1-3 , August , 2015 , Pages 27-40 ; 10075704 (ISSN) Abedini, M ; Nojoumian, M. A ; Salarieh, H ; Meghdari, A ; Sharif University of Technology
    Elsevier  2015
    Abstract
    In this paper, model reference control of a fractional order system has been discussed. In order to control the fractional order plant, discrete-time approximation methods have been applied. Plant and reference model are discretized by Grünwald-Letnikov definition of the fractional order derivative using "Short Memory Principle". Unknown parameters of the fractional order system are appeared in the discrete time approximate model as combinations of parameters of the main system. The discrete time MRAC via RLS identification is modified to estimate the parameters and control the fractional order plant. Numerical results show the effectiveness of the proposed method of model reference adaptive... 

    On tuning and complexity of an adaptive model predictive control scheduler

    , Article Control Engineering Practice ; Volume 15, Issue 9 , 2007 , Pages 1169-1178 ; 09670661 (ISSN) Mahramian, M ; Taheri, H ; Haeri, M ; Sharif University of Technology
    2007
    Abstract
    In this paper, adaptive model predictive control is applied to schedule differentiated buffers in routers. The proposed algorithm, adaptive model predictive control scheduler (AMPCS), dynamically regulates the service rates of aggregated traffic classes. This algorithm guarantees some required constraints on proportional or absolute delay. The control parameters and the way they are adjusted as well as the problems of implementing the controller at high data rates are investigated. Theoretical analysis and numerical simulations demonstrate stability of AMPCS and its acceptable quality of service differentiations at core routers while maintaining end to end delay constraints. © 2007 Elsevier... 

    Comparative analytical performance evaluation of adaptivity in wormhole-switched hypercubes

    , Article Simulation Modelling Practice and Theory ; Volume 15, Issue 4 , 2007 , Pages 400-415 ; 1569190X (ISSN) Patooghy, A ; Sarbazi Azad, H ; Sharif University of Technology
    2007
    Abstract
    In this paper, we study the effect of adaptivity of the routing algorithm on the overall performance of a hypercube multicomputer using wormhole switching. To this end, we use three accurate analytical models proposed for deterministic, fully-adaptive, and partially-adaptive routing algorithms in the hypercube. We compare these three different classes of routing algorithms under different working conditions and structural factors. It is widely believed that the level of adaptivity can result in better performance. Our analysis shows that under uniform traffic load, the employed partially-adaptive routing algorithm exhibits a lower performance compared to the considered deterministic routing... 

    Adaptive synchronization of chaotic systems with uncertain parameters

    , Article 2006 SICE-ICASE International Joint Conference, Busan, 18 October 2006 through 21 October 2006 ; 2006 , Pages 4419-4422 ; 8995003855 (ISBN); 9788995003855 (ISBN) Khademian, B ; Haeri, M ; Sharif University of Technology
    2006
    Abstract
    In this paper, an approach for adaptive synchronization of uncertain chaotic systems is proposed using adaptive active control. According to the Lyapunov stability theorem, an adaptive control law is derived to make the states of two identical chaotic systems asymptotically synchronized. Simulation results are presented to show the effectiveness of the proposed method. © 2006 ICASE