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Impulsive synchronization of different hyperchaotic (chaotic) systems
, Article Chaos, Solitons and Fractals ; Volume 38, Issue 1 , 2008 , Pages 120-131 ; 09600779 (ISSN) ; Dehghani, M ; Sharif University of Technology
2008
Abstract
The impulsive synchronization has been employed to synchronize two different hyperchaotic (chaotic) systems. Conditions on impulse distances are given in order to obtain stable synchronization in the nominal case and robust stability in the case that we experience uncertainties in the systems dynamic and/or measurement noise. Under the given conditions, it is guaranteed that the error dynamics is asymptotically stable for the nominal case and convergent to a predetermined level for uncertain and/or noisy circumstances. Computer simulations are provided to assess results of the given theorems in the paper. © 2006 Elsevier Ltd. All rights reserved
Robust stability of impulsive synchronization in hyperchaotic systems
, Article Communications in Nonlinear Science and Numerical Simulation ; Volume 14, Issue 3 , 2009 , Pages 880-891 ; 10075704 (ISSN) ; Dehghani, M ; Sharif University of Technology
2009
Abstract
In this paper the impulsive synchronization of general continuous chaotic and hyperchaotic systems is investigated. The robust stability of the synchronization method is examined in the presence of uncertainties both on linear and nonlinear parts of the system dynamics and the channel noise. Conditions on the impulse distances are derived for different cases. Numerical simulations are presented to show the effectiveness of the method. © 2007 Elsevier B.V. All rights reserved
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) ; 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
Resource Allocation in mmWave Massive MIMO Transmission in the Presence of Neighboring Cells Interference
, M.Sc. Thesis Sharif University of Technology ; Nasiri Kenari, Masoumeh (Supervisor)
Abstract
In Massive multiple input multiple output (MIMO) systems, due to utilizing a large antenna array in each base station, each user’s channel is orthogonal to one another. These systems have some valuable advantages such as the reduction of energy needed for transmission and significant improvement in spectral efficiency, which makes them be suitable for the next generation of wireless communication systems. In this thesis a massive MIMO working is considered on TDD mode, for wich the channel estimation is done in the base station using the pilot sequences recieved from users. At the beginning of each coherence block, users send their pilot sequences and the rest of the times is allocated to...
Logistics Improvement of Irankhodro L90 Production Site
, M.Sc. Thesis Sharif University of Technology ; Modarres Yazdi, Mohammad (Supervisor)
Abstract
The main purpose of this Thesis is to study logistics situation of L90 production site at Iran khodro Co. and improving it to achieve the project and investment goals. Some proposals in the fields of plant layout redesign, inbound logistics, material flow analysis, and Kanban and synchrony systems development are offered. Plant layout optimization based on allowing facilities parting into more than one section is studied and its mathematical model is developed. A heuristic alogorithm for this type of FLP’s has been offered which optimizes a given solution. The propsed methodology is applied on a real case-Iran khdro L90 site and the obtained solution indicates good results of the algorithm....
Throughput enhancement for repetitive internal cores in latency-insensitive systems
, Article IET Computers and Digital Techniques ; Volume 6, Issue 5 , 2012 , Pages 342-352 ; 17518601 (ISSN) ; Hessabi, S ; Goudarzi, M ; Sharif University of Technology
IEEE
2012
Abstract
Latency-insensitive design (LID) is a correct by-construction methodology for system on chip design that prevents multiple iterations in synchronous system design. However, one problem in the LID is system throughput reduction. In this study, a protocol is proposed to increase the throughput of internal cores in the latency-insensitive systems when there are several repetitive structures. The validation of the protocol is checked for latency equivalency in various system graphs. A shell wrapper to implement the protocol is described and superimposed logic gates for the shell wrapper are formulated. Simulation is performed for 12 randomly generated systems and four actual systems. The...
Modified impulsive synchronization of hyperchaotic systems
, Article Communications in Nonlinear Science and Numerical Simulation ; Volume 15, Issue 3 , 2010 , Pages 728-740 ; 10075704 (ISSN) ; Dehghani, M ; Sharif University of Technology
2010
Abstract
In an original impulsive synchronization only instantaneous errors are used to determine the impulsive inputs. To improve the synchronization performance, addition of an integral term of the errors is proposed here. In comparison with the original form, the proposed modification increases the impulse distances which leads to reduction in the control cost as the most important characteristic of the impulsive synchronization technique. It can also decrease the error magnitude in the presence of noise. Sufficient conditions are presented through four theorems for different situations (nominal, uncertain, noisy, and noisy uncertain cases) under which stability of the error dynamics is...
Asynchronous downlink massive MIMO networks: A stochastic geometry approach
, Article IEEE Transactions on Wireless Communications ; Volume 19, Issue 1 , 2020 , Pages 579-594 ; Azimi Abarghouyi, S. M ; Makki, B ; Nasiri Kenari, M ; Svensson, T ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Massive multiple-input multiple-output (M-MIMO) is recognized as a promising technology for the next generation of wireless networks because of its potential to increase the spectral efficiency. In initial studies of M-MIMO, the system has been considered to be perfectly synchronized throughout the entire cells. However, perfect synchronization may be hard to attain in practice. Therefore, we study a M-MIMO system whose cells are not synchronous to each other, while transmissions in a cell are still synchronous. We analyze an asynchronous downlink M-MIMO system in terms of the coverage probability and the ergodic rate by means of the stochastic geometry tool. For comparison, we also obtain...
Adaptive chaos synchronization in Chua's systems with noisy parameters
, Article Mathematics and Computers in Simulation ; Volume 79, Issue 3 , December , 2008 , Pages 233-241 ; 03784754 (ISSN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
Using the Lyapunov stability theory an adaptive control is proposed for chaos synchronization between two Chua systems which have stochastically time varying unknown coefficients. The stochastic variations of the coefficients around their unknown mean values are modeled through Gaussian white noise produced by the Wiener process. It is shown that using the proposed adaptive control the mean square of synchronization error converges to an arbitrarily small bound around zero depending on the controller feedback gain. Simulation results indicate that the proposed adaptive controller has a high performance in synchronization of chaotic Chua circuits in noisy environment. © 2007 IMACS