Search for: digital-implementation
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    Fully Digital Implementation and Optimization of Openhole Oil Well Surface Modem

    , M.Sc. Thesis Sharif University of Technology Shahbazi Dastgerdeh, Mehdi (Author) ; Movahedian, Hamid (Supervisor) ; Gholampour, Iman (Co-Supervisor)
    Once a well has been drilled before it is cased with the steels (open-hole well), some logging must be done to record information’s about layers, geologic formations, geophysical and petrophysical properties of well. All the information’s that gathered from sensors and tools transmitted to the surface by a down-hole modem. This information is corrupted during the transmission by the communication channel. The most notable influence of this channel is noise, attenuation and interference between successive data bits. On the other hand, the characteristic of channel changes with the length of the cable, temperature, connections and so on. So using a set of fixed filters is not effective. The... 

    Modeling, Design and Efficient Low-Cost Digital Implementation of Millimeter-Wave Imaging System

    , Ph.D. Dissertation Sharif University of Technology Shayei, Ali (Author) ; Shabany, Mahdi (Supervisor) ; Kavehvash, Zahra (Co-Supervisor)
    Recently, there has been an increasing trend towards the use of millimeter-wave (MMW) imaging in various detection applications. This is mainly due to two factors: first, the radiation in the MMW band (30–300 GHz) is nonionizing and safe to use and second, it is able to penetrate through most dielectric materials as well as poor weather conditions, such as smoke and fog. With these potentials, MMW imaging has been used in a variety of applications, including target surveillance and precision target imaging, safe aircraft landing, highway traffic monitoring in fog, remote sensing for civil applications and concealed threat object detection for security concerns. Moreover, it can also find... 

    Biologically inspired spiking neurons: Piecewise linear models and digital implementation

    , Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 59, Issue 12 , 2012 , Pages 2991-3004 ; 15498328 (ISSN) Soleimani, H ; Ahmadi, A ; Bavandpour, M ; Sharif University of Technology
    There has been a strong push recently to examine biological scale simulations of neuromorphic algorithms to achieve stronger inference capabilities. This paper presents a set of piecewise linear spiking neuron models, which can reproduce different behaviors, similar to the biological neuron, both for a single neuron as well as a network of neurons. The proposed models are investigated, in terms of digital implementation feasibility and costs, targeting large scale hardware implementation. Hardware synthesis and physical implementations on FPGA show that the proposed models can produce precise neural behaviors with higher performance and considerably lower implementation costs compared with... 

    Digital implementation of a biological astrocyte model and its application

    , Article IEEE Transactions on Neural Networks and Learning Systems ; Volume 26, Issue 1 , 2014 , Pages 127-139 ; 2162237X (ISSN) Soleimani, H ; Bavandpour, M ; Ahmadi, A ; Abbott, D ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2014
    This paper presents a modified astrocyte model that allows a convenient digital implementation. This model is aimed at reproducing relevant biological astrocyte behaviors, which provide appropriate feedback control in regulating neuronal activities in the central nervous system. Accordingly, we investigate the feasibility of a digital implementation for a single astrocyte and a biological neuronal network model constructed by connecting two limit-cycle Hopf oscillators to an implementation of the proposed astrocyte model using oscillator-astrocyte interactions with weak coupling. Hardware synthesis, physical implementation on field-programmable gate array, and theoretical analysis confirm... 

    Wind energy conversion system based on DFIG with open switch fault tolerant six-legs AC-DC-AC converter

    , Article Proceedings of the IEEE International Conference on Industrial Technology, Cape Town ; February , 2013 , Pages 1656-1661 ; 9781467345699 (ISBN) Shahbazi, M ; Zolghadri, M. R ; Poure, P ; Saadate, S ; The Institute of Electrical and Electronics Engineers (IEEE); IEEE Industrial Electronics Society (IES); IEEE Technology Management Council; IEEE Region 8; IEEE South Africa Section IE/IA/PEL Joint Chapter ; Sharif University of Technology
    Continuity of service of wind energy conversion systems as well as their reliability and performances are some of the major concerns in this power generation area. Six-legs AC/DC/AC converters are normally used in modern wind energy systems like as in the system with a doubly-fed induction generator (DFIG). A sudden failure of the converter can lead to the total or partial loss of the control of the phase currents and can cause serious system malfunction or shutdown. Therefore, to prevent the spread of the fault to the other system components and to ensure continuity of service, fault tolerant converter topologies associated to quick and effective fault detection and compensation methods... 

    Networked adaptive non-linear oscillators: A digital synthesis and application

    , Article Circuits, Systems, and Signal Processing ; Vol. 34, Issue. 2 , 2014 , pp. 483-512 ; ISSN: 1531-5878 Maleki, M. A ; Ahmadi, A ; Makki, S. V. A. - D ; Soleimani, H ; Bavandpour, M ; Sharif University of Technology
    This paper presents a digital hardware implementation of a frequency adaptive Hopf oscillator along with investigation on systematic behavior when they are coupled in a population. The mathematical models of the oscillator are introduced and compared in sense of dynamical behavior by using system-level simulations based on which a piecewise-linear model is developed. It is shown that the model is capable to be implemented digitally with high efficiency. Behavior of the oscillators in different network structures to be used for dynamic Fourier analysis is studied and a structure with more precise operation which is also more efficient for FPGA-based implementation is implemented. Conceptual... 

    Design a LQG power system stabilizer for bistun power plant

    , Article AUPEC'09 - 19th Australasian Universities Power Engineering Conference: Sustainable Energy Technologies and Systems, 27 September 2009 through 30 September 2009, Adelaide ; 2009 ; 9780863967184 (ISBN) Keivanian, R ; Hossein Vahabie, A ; Nademi, H ; Ranjbar, A ; Sharif University of Technology
    Design of a classical controller is based on output feedback and structure of the controller. From modern control point of view, the information of input signals, output signals and internal behavior of the system are presented in state space model. In this paper, modern control is used to increase small-disturbance stability of power systems. Although many of existing power plants prefer to use classical Power System Stabilizers (PSS), these controllers have their own problems. Digital implementation of modern controllers is considered as a good advantage of modern PSS. In this paper, a modern control based PSS is designed for Bistun power plant and its output results are compared to the... 

    Extraction of harmonics and reactive current for power quality enhancement

    , Article International Symposium on Industrial Electronics 2006, ISIE 2006, Montreal, QC, 9 July 2006 through 13 July 2006 ; Volume 3 , 2006 , Pages 1673-1678 ; 1424404975 (ISBN); 9781424404971 (ISBN) Karimi Ghartemani, M ; Mokhtari, H ; Sharif University of Technology
    A detection technique for extraction of total harmonics, individual harmonics, and reactive current components is introduced and its performance is evaluated. The detection algorithm is then adopted as part of the control system of a single-phase active power filter (APF) to provide the required signals for harmonic filtering and reactive power compensation. Performance of the overall system is evaluated based on digital time-domain simulation studies. The APF control system including the signal processing algorithms are implemented in Matlab/Simulink Fixed-Point Blockset to accommodate bit-length limitation which is a crucial factor in digital implementation. The power system including the... 

    Wireless optical CDMA LAN: digital implementation analysis

    , Article IEEE Journal on Selected Areas in Communications ; Volume 27, Issue 9 , 2009 , Pages 1676-1686 ; 07338716 (ISSN) Ghaffari, B. M ; Matinfar, M. D ; Salehi, J. A ; Sharif University of Technology
    In this paper we present and investigate a digital design and implementational details of a wireless optical CDMA (OCDMA) system based on generalized optical orthogonal codes (OOCs). A detailed digital implementation analysis and transmitter/receiver architectures in the context of the above design are fully studied. We analyze various subsystems for a wireless OCDMA system including detector and receiver structure, acquisition, and tracking blocks as well as evaluating their performance in a typical wireless OCDMA communication system. By analyzing two main parts of the system, namely, chip-level detector and OCDMA receiver blocks we evaluate the performance of the overall system....