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    Simulation of Pulse Propagation in Fiber Based on Space-Time Factorization

    , M.Sc. Thesis Sharif University of Technology Farhoudi, Ramtin (Author) ; Mehrany, Khashayar (Supervisor)
    Abstract
    In this thesis, equations governing the pulse propagation in fiber optics are investigated and methods for numerical solution of these equations are modified or extended to more general cases. First, the extraction of these equations from Maxwell's equations is explained and then the numerical methods are discussed. For extracting the equations, we assume the fiber medium as a longitudinally inhomogeneous medium, so the coupling between the forward and backward waves is taken into account. In addition, the effect of birefringence in fiber is included in the analysis and its modeling as a stochastic process is explained in detail. Two numerical methods based on operator splitting technique... 

    Time-domain split-step method with variable step-sizes in vectorial pulse propagation by using digital filters

    , Article Optics Communications ; Volume 283, Issue 12 , June , 2010 , Pages 2518-2524 ; 00304018 (ISSN) Farhoudi, R ; Mehrany, K ; Sharif University of Technology
    2010
    Abstract
    Finite impulse response (FIR) and infinite impulse response (IIR) digital filters are proposed to allow for time-domain simulation of optical pulse propagation by using the operator-splitting technique. These filters simulate polarization mode dispersion and chromatic dispersion effects with acceptable accuracy in time-domain. An analytical relation between the coefficients of these filters and the simulation step-size is established to accommodate the possibility of carrying out the time-domain split-step method with variable split-step length at virtually no computational burden. The superiority of the proposed method over the conventional frequency-domain technique is particularly... 

    Short-run process control based on non-conformity degree

    , Article World Congress on Engineering 2010, WCE 2010, London, 30 June 2010 through 2 July 2010 ; Volume 3 , 2010 , Pages 2273-2276 ; 20780966(Online ISSN) ; 9789881821089 (ISBN) Aminnayeri, M ; Torkamani, E. A ; Davodi, M ; Ramtin, F ; IAENG Society of Artificial Intelligence ; Sharif University of Technology
    2010
    Abstract
    Statistical Process Control (SPC) is an approach that uses statistical techniques to monitor the process. The techniques of quality control are widely used in controlling any kinds of processes. One of these processes is the short processes. In short run processes often do not have enough data in each run to produce good estimates of the process parameters. This will cause the reduction of the performance and efficiency of control charts. A common solution to this problem is considering a single machine or process to produce many different parts, or different products. In this paper a new method based on non-conformity degree and fuzzy membership functions has been developed for controlling...