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    Wavelength assignment in hybrid quantum-classical networks

    , Article Scientific Reports ; Volume 8, Issue 1 , 2018 ; 20452322 (ISSN) Bahrani, S ; Razavi, M ; Salehi, J. A ; Sharif University of Technology
    Nature Publishing Group  2018
    Optimal wavelength assignment in dense-wavelength-division-multiplexing (DWDM) systems that integrate both quantum and classical channels is studied. In such systems, weak quantum key distribution (QKD) signals travel alongside intense classical signals on the same fiber, where the former can be masked by the background noise induced by the latter. Here, we investigate how optimal wavelength assignment can mitigate this problem. We consider different DWDM structures and various sources of crosstalk and propose several near-optimal wavelength assignment methods that maximize the total secret key rate of the QKD channels. Our numerical results show that the optimum wavelength assignment... 

    General noise considerations of amplified photons in lightwave systems with optically bistable elements

    , Article Proceedings - 10th International Conference on Laser and Fiber-Optical Networks Modeling, LFNM 2010, 12 September 2010 through 14 September 2010 ; 2010 , Pages 93-95 ; 9781424469970 (ISBN) Abediasl, H ; Naqavi, A ; Mehrany, K ; Mousavi, S. M ; Aliakbar, J ; Mousavi, S. M ; Sharif University of Technology
    An optical amplifier followed by a bistable element has been statistically analyzed before [1]. In this manuscript, output noise analysis represents, then signal to noise ratios (SNR) are calculated either for input or output. It will be shown that noise reduction, can be achieved by a proper selection of parameters  

    Adaptive group of ink drop spread: A computer code to unfold neutron noise sources in reactor cores

    , Article Nuclear Engineering and Technology ; 2017 ; 17385733 (ISSN) Hosseini, S. A ; Esmaili PaeenAfrakoti, I ; Sharif University of Technology
    Korean Nuclear Society  2017
    The present paper reports the development of a computational code based on the Adaptive Group of Ink Drop Spread (AGIDS) for reconstruction of the neutron noise sources in reactor cores. AGIDS algorithm was developed as a fuzzy inference system based on the active learning method. The main idea of the active learning method is to break a multiple input-single output system into a single input-single output system. This leads to the ability to simulate a large system with high accuracy. In the present study, vibrating absorber-type neutron noise source in an International Atomic Energy Agency-two dimensional reactor core is considered in neutron noise calculation. The neutron noise... 

    Noise pollution assessment in khoramabad to presenting executive strategies to control or reduce it

    , Article Journal of Environmental Studies ; Volume 35, Issue 50 , 2009 , Pages 83-96 ; 10258620 (ISSN) Kiani Sadr, M ; Nassiri, P ; Sekhavatjo, M ; Abbaspour, M ; Sharif University of Technology
    Noise population is one of the most important environmental pollution cases that cause some troubles for inhabitants and employees in city limit and it is seriously considered as a hygienic risky case and even immunity in the world (Abaspour, 1992).The population of khoramabad city as Lorestan state capital has been 305590, on the basis of population estimate in 2003. It has three-city area and it is located at north-southern corridor of country (management and planning organization of Lorestan province 2004).The matter lead to great bulk of jam that pass through the passageway and linking line that cross through khoramabad city and caused diffusion of many kinds of pollution specially noise... 

    High accurate three-dimensional neutron noise simulator based on GFEM with unstructured hexahedral elements

    , Article Nuclear Engineering and Technology ; Volume 51, Issue 6 , 2019 , Pages 1479-1486 ; 17385733 (ISSN) Hosseini, S.A ; Sharif University of Technology
    Korean Nuclear Society  2019
    The purpose of the present study is to develop the 3D static and noise simulator based on Galerkin Finite Element Method (GFEM) using the unstructured hexahedral elements. The 3D, 2G neutron diffusion and noise equations are discretized using the unstructured hexahedral by considering the linear approximation of the shape function in each element. The validation of the static calculation is performed via comparison between calculated results and reported data for the VVER-1000 benchmark problem. A sensitivity analysis of the calculation to the element type (unstructured hexahedral or tetrahedron elements) is done. Finally, the neutron noise calculation is performed for the neutron noise... 

    An analytical approach in calculation of noise spectrum in microwave oscillators based on harmonic balance

    , Article IEEE Transactions on Microwave Theory and Techniques ; Volume 48, Issue 5 , 2000 , Pages 822-831 ; 00189480 (ISSN) Mehrshahi, E ; Farzaneh, F ; Sharif University of Technology
    In this paper, a novel method for nonlinear analysis of noise in microwave oscillators is presented. Based on harmonic balance, the method is general from the point-of-view of circuit topology, noise sources spectral distribution, and their cross correlation. In this method, the effects such as frequency conversion and frequency modulation are considered simultaneously in a unified treatment. Relatively precise estimations for the output signal spectral density of an oscillator is practically obtained. © 2000 IEEE  

    A novel approach to array steering vector estimate improvement

    , Article 2000 10th European Signal Processing Conference, EUSIPCO 2000, 4 September 2000 through 8 September 2000 ; Volume 2015-March, Issue March , 2000 ; 22195491 (ISSN) Biguesh, M ; Champagne, B ; Valaee, S ; Sharif University of Technology
    European Signal Processing Conference, EUSIPCO  2000
    In this paper, we present a method for estimating the signal sources steering vector using an arbitrary planar array with omnidirectional elements. The proposed method improves the initial estimation of the signal steering vector in two steps. In the first step of this algorithm we minimize of the distance between the steering vector and the signal subspace. The second step improves the estimation of the first step using a defined cost function which is based on a structural criterion for signal steering vector. Simulation results show the capability of the proposed signal steering vector estimate improvement. © 2000 EUSIPCO  

    An optimal wavelet filtering method for noise suppression of PD measured signal and its location in power transformer winding

    , Article 2005 IEEE International Conference on Dielectric Liquids, ICDL 2005, Coimbra, 26 June 2005 through 1 July 2005 ; 2005 , Pages 269-272 ; 0780389549 (ISBN); 9780780389540 (ISBN) Naderi, M. S ; Vakilian, M ; Blackburn, T. R ; Phung, B. T ; Nam O, H ; Naderi, M. S ; Sharif University of Technology
    In this paper a method for selecting optimal wavelet is introduced, which is implemented for evaluating electrical measured partial discharges on a 66 kV/25 MVA fully interleaved winding of a power transformer. Applying wavelet transform to a signal produces a wavelet detail coefficient distribution throughout the time-scale, which depends on the wavelet chosen. This method is based on the capability of the chosen wavelet for generating coefficients with maximal values. The basic idea of this method is described and applications to partial discharge studies are explored. The paper demonstrates that the wavelet based de-noising method proposed in the paper can be employed in extracting the PD... 

    A comprehensive study on noise reduction methods of marine propellers and design procedures

    , Article Applied Acoustics ; Volume 150 , 2019 , Pages 55-69 ; 0003682X (ISSN) Ebrahimi, A ; Razaghian, A. H ; Seif, M. S ; Zahedi, F ; Nouri Borujerdi, A ; Sharif University of Technology
    Elsevier Ltd  2019
    The noise generated by the propeller is one of the most important components of the vessels noise. Therefore, reducing this noise will significantly decrease the total noise of the vessel. Underwater noise of vessels has destructive effects on marine life. In addition, this noise affects the health and comfort of the crew and passengers of the ship. Moreover, high noise may cause warships to be detected easily. In this paper, first, common methods of noise reduction, including blade coating, modern propellers, propeller hub modification and ducted propellers are investigated. Then, relevant optimization methods are presented. Next, the effects of the geometric parameters like number of... 

    A new lattic LP-based post filter for adaptive noise cancellers in mobile and vehicular applications

    , Article Proceedings of the 8th IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2008, 16 December 2008 through 19 December 2008, Sarajevo ; 2008 , Pages 407-412 ; 9781424435555 (ISBN) Khorram, S ; Sameti, H ; Veisi, H ; Abutalebi, H. R ; Sharif University of Technology
    Adaptive Noise Cancellation (ANC) is a well-known technique for background noise reduction in automobile and vehicular environments. The noise fields in automobile and other vehicle interior obey the diffuse noise field model closely. On the other hand, the ANC does not provide sufficient noise reduction in the diffuse noise fields. In this paper, a new multistage post-filter is designed for ANC as a solution to diffuse noise conditions. The designed post-filter is a single channel Linear Prediction (LP) based speech enhancement system. The LP is performed by an adaptive lattice filter and attempts to extract speech components by using intermediate ANC signals. The post-filter has no... 

    Second and third-order distortion suppression technique for noise canceling CMOS LNAs

    , Article IEICE Electronics Express ; Volume 6, Issue 13 , 2009 , Pages 959-965 ; 13492543 (ISSN) Saeedi, S ; Atarodi, M ; Sharif University of Technology
    A technique for simultaneous cancellation of noise, second-order distortion and third-order distortion in CMOS LNAs is presented. The proposed LNA topology consists of a matching stage and two common-source amplifier stages, performing single-ended to differential signal conversion with balanced output. The second and third-order nonlinearity of the individual amplifiers as well as the distortion caused by the interaction between the stages are suppressed to achieve high IIP3. A method for intrinsic cancellation of the second-order interaction is employed to reduce the dependence of the IIP3 on the frequency spacing between the interfering signals in the two-tone test. © IEICE 2009  

    Statistical analysis of sidelobes in random phase-modulated radars

    , Article Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011, 24 October 2011 through 27 October 2011, Chengdu ; Volume 1 , October , 2011 , Pages 485-489 ; 9781424484416 (ISBN) Jariani, H. H ; Bahadori, M ; Tohidi, E ; Majd, M. N ; Nayebi, M. M ; Sharif University of Technology
    Target detection in noise radar is always done by computing cross-correlation between transmitted and received signals. In this process, side lobes of a strong target emerge and make some troubles in detection of weak ones (Masking Effect). Therefore, finding methods to suppress this effect becomes important. These methods can be implemented at the transmitter or receiver or at both to achieve more improvement. There are many new methods developed for the receiver side and a few methods applicable at the transmitter side. The main idea of suppressing side lobes at the transmitter is to design a specific noise signal instead of using purely random noise. In this paper we begin with... 

    On the capacity of signal dependent noise channels

    , Article IWCIT 2017 - Iran Workshop on Communication and Information Theory, 3 May 2017 through 4 May 2017 ; 2017 ; 9781509047833 (ISBN) Aminian, G ; Ghourchian, H ; Gohari, A ; Mirmohseni, M ; Nasiri Kenari, M ; Sharif University of Technology
    In some applications, the variance of measurement noise depends on the signal that we aim to measure. For instance, additive Gaussian signal-dependent noise (AGSDN) channel models are used in molecular and optical communication. Herein we provide lower and upper bounds on the capacity of additive signal dependent noise (ASDN) channels. We also provide sufficient conditions under which the capacity becomes infinity. © 2017 IEEE  

    Detection and extraction of periodic noises in audio and biomedical signals using Kalman filter

    , Article Signal Processing ; Volume 88, Issue 8 , August , 2008 , Pages 2114-2121 ; 01651684 (ISSN) Kazemi, R ; Farsi, A ; Ghaed, M. H ; Karimi Ghartemani, M ; Sharif University of Technology
    This paper studies the subject of adaptive noise cancelation using the Kalman filtering technique to achieve high precision and fast convergence. It is shown that the Kalman filter can successfully be designed to detect and extract periodic noises which may be constituted of different sinusoidal components with possibly unknown and/or time-varying frequencies. This highlights the feature of Kalman filter in synthesizing periodic noises in the time-domain which is not possible using Fourier-based methods such as DFT. Usefulness of the method is discussed in the context of two examples: active cancelation of periodic noises from audio waveforms and filtering of electrocardiogram measurements.... 

    Impulsive noise cancellation using CFAR and iterative techniques

    , Article 2008 International Conference on Telecommunications, ICT, St. Petersburg, 16 June 2008 through 19 June 2008 ; October , 2008 ; 9781424420360 (ISBN) Zahedpour, S ; Feizi, S ; Amini, A ; Ferdosizadeh, M ; Marvasti, F ; Sharif University of Technology
    In this paper we propose a new method to recover bandlimited signals corrupted by impulsive noise. The proposed method uses CFAR adaptive thresholding and soft decision making to detect the locations of the impulsive noise. Then an iterative method cancels noise and reconstructs the signal. This estimate in turn will be used to make the approximation of the impulsive noise more accurate. Simulation results confirm the robustness of the proposed algorithm even when impulsive noise exceeds the theoretical reconstruction capacity. ©2008 IEEE  

    A new low-power sigma-delta modulator with the reduced number of op-amps for speech band applications

    , Article Proceedings of the 2003 IEEE International Symposium on Circuits and Systems, Bangkok, 25 May 2003 through 28 May 2003 ; Volume 1 , 2003 , Pages I1033-I1036 ; 02714310 (ISSN) Safarian, A. Q ; Sahandi, F ; Mojtaba Atarodi, S ; Sharif University of Technology
    An area and power-efficient second order sigma-delta modulator is presented. At system level, we propose a new single-loop single-stage modulator that uses only one class-AB op-amp to realize a second order noise shaping for speech band applications. The modulator shows 86 dB DR in 4 kHz speech bandwidth. It consumes 125 μw from a 2.5 V supply  

    Panel contribution analysis for a sedan car using numerical simulations

    , Article 20th International Congress on Sound and Vibration 2013, ICSV 2013 ; Volume 4 , 2013 , Pages 2891-2898 ; 9781629931500 Jahani, K ; Beigmoradi, S ; Ramezani, A ; Hajabdollahi, H ; LMS ; Sharif University of Technology
    International Institute of Acoustics and Vibrations  2013
    These days, the pace of utilizing CAE tools is increasing with an eye to the vehicle development time and cost considerations. This paper deals with the NVH virtual analyses performed for a trimmed body of a B-segment sedan car. Since the main source of annoyance in low frequency range is the booming noise, the NVH diagnoses are performed by FEM tools. Firstly, the finite element model of the car is generated and this is followed by the modal analysis simulations for the car and cavity models in order to investigate the frequency attributes of the car and identify the NVH characteristics of body structure and acoustic cavity. Afterwards, noise transfer function (NTF) analyses are performed... 

    Noise effects in perfect transmission of quantum states

    , Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 86, Issue 6 , October , 2012 ; 10502947 (ISSN) Benatti, F ; Floreanini, R ; Karimipour, V ; Sharif University of Technology
    A recent scheme for perfect transmission of quantum states through quasi-one-dimensional chains requires application of global control at regular intervals of time. We study the effect of stochastic noise in this control and find that the scheme is robust for reasonable values of disorder. Both uncorrelated and correlated noise in the external control are studied, and it is remarkably found that the efficiency of the protocol is much higher in the presence of correlated noise  

    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
    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  

    Impulsive noise removal from images using sparse representation and optimization methods

    , Article 10th International Conference on Information Sciences, Signal Processing and their Applications, ISSPA 2010, 10 May 2010 through 13 May 2010 ; May , 2010 , Pages 480-483 ; 9781424471676 (ISBN) Beygi Harchegani, S ; Kafashan, M ; Marvasti, F ; Sharif University of Technology
    In this paper, we propose a new method for impulsive noise removal from images. It uses the sparsity of natural images when they are expanded by mean of a good learned dictionary. The zeros in sparse domain give us an idea to reconstruct the pixels that are corrupted by random-value impulse noises. This idea comes from this reality that noisy image in sparse domain of original image will not have a sparse representation as much as original image sparsity. In this method we assume that the proper dictionary to achieve image in sparse domain is available