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    Natural frequencies of C60, C70, and C80 fullerenes

    , Article Applied Physics Letters ; Volume 96, Issue 2 , 2010 ; 00036951 (ISSN) Sakhaee Pour, A ; Vafai, A ; Sharif University of Technology
    Abstract
    This letter adopts an atomistic modeling approach to study free vibrational characteristics of C60, C70, and C80 fullerenes. In this regard, we use the molecular structural mechanics consisting of equivalent structural beams to calculate the nonzero natural frequencies. The simulation results indicate that the first natural frequency of the fullerene is in the order terahertz and decreases nonlinearly with respect to the number of the carbon atoms  

    Compensating interpolation distortion by new optimized modular method

    , Article 2011 18th International Conference on Telecommunications, ICT 2011 ; 2011 , Pages 346-350 ; 9781457700248 (ISBN) Ayremlou, A ; Tofighi, M ; Marvasti, F ; IBM Cyprus; University of Cyprus; Cyprus Tourism Organisation ; Sharif University of Technology
    Abstract
    A modular method was suggested before to recover a band limited signal from the sample and hold and linearly interpolated (or, in general, an nth-order-hold) version of the regular samples. In this paper a novel approach for compensating the distortion of any interpolation based on modular method has been proposed. In this method the performance of the modular method is optimized by adding only some simply calculated coefficients. This approach causes drastic improvement in terms of signal-to-noise ratios with fewer modules compared to the classical modular method. Simulation results clearly confirm the improvement of the proposed method and also its superior robustness against additive... 

    Using non-negative matrix factorization for removing show-through

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 27 September 2010 through 30 September 2010 ; Volume 6365 LNCS , September , 2010 , Pages 482-489 ; 03029743 (ISSN) ; 9783642159947 (ISBN) Merrikh Bayat, F ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
    2010
    Abstract
    Scanning process usually degrades digital documents due to the contents of the backside of the scanned manuscript. This is often because of the show-through effect, i.e. the backside image that interferes with the main front side picture mainly due to the intrinsic transparency of the paper used for printing or writing. In this paper, we first use one of Non-negative Matrix Factorization (NMF) methods for canceling show-through phenomenon. Then, non-linearity of show-through effect is included by changing the cost function used in this method. Simulation results show that this proposed algorithm can remove show-through effectively  

    Blind separation of bilinear mixtures using mutual information minimization

    , Article Machine Learning for Signal Processing XIX - Proceedings of the 2009 IEEE Signal Processing Society Workshop, MLSP 2009, 2 September 2009 through 4 September 2009, Grenoble ; 2009 ; 9781424449484 (ISBN) Mokhtari, F ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
    Abstract
    In this paper an approach for blind source separation in bilinear (or linear quadratic) mixtures is presented. The proposed algorithm employs the same recurrent structure as [Hosseini and Deville, 2003) for separating these mixtures . However, instead of maximal likelihood, our algorithm is based on minimizing the mutual information of the outputs for recovering the independent components. Simulation results show the efficiency of the proposed algorithm. © 2009 IEEE  

    A novel secret sharing scheme from audio perspective

    , Article 2008 International Symposium on Telecommunications, IST 2008, Tehran, 27 August 2008 through 28 August 2008 ; October , 2008 , Pages 13-18 ; 9781424427512 (ISBN) Ehdaie, M ; Eghlidos, T ; Aref, M. R ; Sharif University of Technology
    2008
    Abstract
    In this paper, a new audio secret sharing scheme which is secure and ideal is proposed. This scheme is (k, n) threshold for k ≥ 2, where the previous schemes were (2, n). It is assumed that both, "shares" and "secret", are audio files instead of a bit string secret proposed in the previous works. The audio secret is reconstructed without any computation, that is only by playing audio shares simultaneously. Moreover, the simulation results shows that the new scheme is not sensitive to audio noise. ©2008 IEEE  

    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
    2008
    Abstract
    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  

    Multispanning tree zone-ordered label-based routing algorithms for irregular networks

    , Article IEEE Transactions on Parallel and Distributed Systems ; Vol. 22, issue. 5 , 2011 , p. 817-832 ; ISSN: 10459219 Moraveji, R ; Moinzadeh, P ; Sarbazi-Azad, H ; Zomaya, A.Y ; Sharif University of Technology
    Abstract
    In this paper, a diverse range of routing algorithms is classified into a new family of routings called zone-ordered label-based routing algorithms. The proposed classification is based on three common steps (factors) for generating such routings, namely, graph labeling, deadlock-free zones, and zone ordering. The main goal of this classification is to define several new routing concepts and streamline the knowledge on routing algorithms. Following the classification, a novel methodology is proposed to generate routing algorithms for irregular networks. The methodology uses the three mentioned steps to generate deadlock-free routings. Consequently, the methodology-based routings fall into... 

    Vibration transfer path analysis and path ranking for NVH optimization of a vehicle interior

    , Article Shock and Vibration ; Vol. 2014, issue , 2014 ; ISSN: 10709622 Sakhaei, B ; Durali, M ; Sharif University of Technology
    Abstract
    By new advancements in vehicle manufacturing, evaluation of vehicle quality assurance has got a more critical issue. Today noise and vibration generated inside and outside the vehicles are more important factors for customers than before. So far several researchers have focused on interior noise transfer path analysis and the results have been published in related papers but each method has its own limitations. In present work, the vibration transfer path analysis and vibration path ranking of a car interior have been performed. As interior vibration is a source of structural borne noise problem, thus, the results of this research can be used to present the structural borne noise state in a... 

    Blind source separation of discrete finite alphabet sources using a single mixture

    , Article IEEE Workshop on Statistical Signal Processing Proceedings, 28 June 2011 through 30 June 2011, Nice ; June , 2011 , Pages 709-712 ; 9781457705700 (ISBN) Rostami, M ; Babaie Zadeh, M ; Samadi, S ; Jutten, C ; Sharif University of Technology
    2011
    Abstract
    This paper deals with blind separation of finite alphabet sources where we have n sources and only one observation. The method is applied directly in time (spatial) domain and no transformation is needed. It follows a two stage procedure. In the first stage the mixing coefficients are estimated, and in the second stage the sources are separated using the estimated mixing coefficients. We also study restrictions of this method and conditions for which its performance is acceptable. Simulation results are presented to show the ability of this method to source separation in images and pulse amplitude modulation (PAM) signals  

    A new iterative position finding algorithm based on Taylor series expansion

    , Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 ; 9789644634284 (ISBN) Soltanian, M ; Pezeshk, A. M ; Mahdavi, A ; Dallali, M ; Sharif University of Technology
    2011
    Abstract
    This paper deals with the problem of estimating the position of emitters using only direction of arrival information. We propose an improvement of newly developed algorithm for position finding of a stationary emitter called sensitivity analysis. The proposed method uses Taylor series expansion iteratively to enhance the estimation of the emitter location and reduce position finding error. Simulation results show that our proposed method makes a great improvement on accuracy of position finding with respect to sensitivity analysis method  

    Learning automata based dynamic guard channel algorithms

    , Article Computers and Electrical Engineering ; Volume 37, Issue 4 , 2011 , Pages 601-613 ; 00457906 (ISSN) Beigy, H ; Meybodi, M. R ; Sharif University of Technology
    2011
    Abstract
    In this paper, we first propose two learning automata based decentralized dynamic guard channel algorithms for cellular mobile networks. These algorithms use learning automata to adjust the number of guard channels to be assigned to cells of network. Then, we introduce a new model for nonstationary environments under which the proposed algorithms work and study their steady state behavior when they use LR-I learning algorithm. It is also shown that a learning automaton operating under the proposed nonstationary environment equalizes its penalty strengths. Computer simulations have been conducted to show the effectiveness of the proposed algorithms. The simulation results show that the... 

    Multispanning tree zone-ordered label-based routing algorithms for irregular networks

    , Article IEEE Transactions on Parallel and Distributed Systems ; Volume 22, Issue 5 , July , 2011 , Pages 817-832 ; 10459219 (ISSN) Moraveji, R ; Moinzadeh, P ; Sarbazi Azad, H ; Zomaya, A. Y ; Sharif University of Technology
    Abstract
    In this paper, a diverse range of routing algorithms is classified into a new family of routings called zone-ordered label-based routing algorithms. The proposed classification is based on three common steps (factors) for generating such routings, namely, graph labeling, deadlock-free zones, and zone ordering. The main goal of this classification is to define several new routing concepts and streamline the knowledge on routing algorithms. Following the classification, a novel methodology is proposed to generate routing algorithms for irregular networks. The methodology uses the three mentioned steps to generate deadlock-free routings. Consequently, the methodology-based routings fall into... 

    An efficient spam mail detection by counter technique

    , Article World Academy of Science, Engineering and Technology ; Volume 74 , May , 2011 , Pages 579-582 ; 2010376X (ISSN) Kholghi, R ; Roudsari, S. B ; Pour, A. N ; Sharif University of Technology
    2011
    Abstract
    Spam mails are unwanted mails sent to large number of users. Spam mails not only consume the network resources, but cause security threats as well. This paper proposes an efficient technique to detect, and to prevent spam mail in the sender side rather than the receiver side. This technique is based on a counter set on the sender server. When a mail is transmitted to the server, the mail server checks the number of the recipients based on its counter policy. The counter policy performed by the mail server is based on some pre-defined criteria. When the number of recipients exceeds the counter policy, the mail server discontinues the rest of the process, and sends a failure mail to sender of... 

    Adaptive and non-adaptive ISI sparse channel estimation based on SL0 and its application in ML sequence-by-sequence equalization

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 27 September 2010 through 30 September 2010 ; Volume 6365 LNCS , September , 2010 , Pages 579-587 ; 03029743 (ISSN) ; 9783642159947 (ISBN) Niazadeh, R ; Hamidi Ghalehjegh, S ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
    2010
    Abstract
    In this paper, we firstly propose an adaptive method based on the idea of Least Mean Square (LMS) algorithm and the concept of smoothed l 0 (SL0) norm presented in [1] for estimation of sparse Inter Symbol Interface (ISI) channels which will appear in wireless and acoustic underwater transmissions. Afterwards, a new non-adaptive fast channel estimation method based on SL0 sparse signal representation is proposed. ISI channel estimation will have a direct effect on the performance of the ISI equalizer at the receiver. So, in this paper we investigate this effect in the case of optimal Maximum Likelihood Sequence-by-sequence Equalizer (MLSE) [2]. In order to implement this equalizer, we... 

    A solution to gain attack on watermarking systems: logarithmic homogeneous rational dither modulation

    , Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, 142010 through 19 March 2010 ; March , 2010 , Pages 1746-1749 ; 15206149 (ISSN) ; 9781424442966 (ISBN) Akhaee, M. A ; Amini, A ; Ghorbani, G ; Marvasti, F ; Sharif University of Technology
    2010
    Abstract
    Among the many attacks against watermarked data, the gain attack is less supported with countermeasures. The effectiveness of this attack becomes more evident in quantization-based embedding algorithms such as Dither Modulation (DM). In this paper, the general solution for both block and sample type DM schemes that are robust against gain attacks is considered. Among the solutions, we concentrate on a subclass of the algorithms which are insensitive to additive noise attacks; i.e., we introduce watermarking schemes which are both robust against gain and additive noise attacks. The simulation results confirm the desired performance of the final algorithm against these attacks while outperform... 

    Parametric dictionary learning using steepest descent

    , Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, 14 March 2010 through 19 March 2010 ; March , 2010 , Pages 1978-1981 ; 15206149 (ISSN) ; 9781424442966 (ISBN) Ataee, M ; Zayyani, H ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
    2010
    Abstract
    In this paper, we suggest to use a steepest descent algorithm for learning a parametric dictionary in which the structure or atom functions are known in advance. The structure of the atoms allows us to find a steepest descent direction of parameters instead of the steepest descent direction of the dictionary itself. We also use a thresholded version of Smoothed- ℓ0 (SL0) algorithm for sparse representation step in our proposed method. Our simulation results show that using atom structure similar to the Gabor functions and learning the parameters of these Gabor-like atoms yield better representations of our noisy speech signal than non parametric dictionary learning methods like K-SVD, in... 

    RMAP: A reliability-aware application mapping for network-on-chips

    , Article Proceedings - 3rd International Conference on Dependability, DEPEND 2010, 18 July 2010 through 25 July 2010 ; July , 2010 , Pages 112-117 ; 9780769540900 (ISBN) Patooghy, A ; Tabkhi, H ; Miremadi, S. G ; IARIA ; Sharif University of Technology
    2010
    Abstract
    This paper proposes a reliability-aware application mapping for mesh-based NoCs. The proposed reliable mapping, called RMAP, adds redundant communications to the application graph in order to improve the reliability of packet delivery in NoCs. The RMAP divides the application graph into two sub-graphs which have the lowest possible communication with each other. One of the sub-graphs is mapped on the upper triangular nodes of the NoC and the other is mapped on the lower triangular nodes. In this way, lower traffic load is imposed on some channels which are efficiently used to route packets of redundant communications. This minimizes the overheads imposed to the NoC due to redundant... 

    Molecular dynamics study of 'success evaluation' for metallic nanoparticles manipulation on gold substrate

    , Article Micro and Nano Letters ; Volume 5, Issue 5 , 2010 , Pages 286-290 ; 17500443 (ISSN) Mahboobi, S. H ; Meghdari, A ; Jalili, N ; Amiri, F ; Sharif University of Technology
    2010
    Abstract
    One of the key factors in the assembly of nanoparticles and controlled construction of such systems is their positioning by a manipulation system. The response of clusters that are subjected to this process is of great importance. In this study, the behaviour of metallic nanoparticles during the manipulation process on an Au substrate is investigated using molecular dynamics. Two criteria are proposed for the evaluation of success in a pushing process regarding the intactness of a nanoparticle/substrate pair. The effects of cluster material, temperature and manipulation speed on the success of the process are investigated based on the simulation results  

    Mobility analyzer: A framework for analysis and recognition of mobility traces in mobile Ad-Hoc networks

    , Article 3rd International Conference on New Technologies, Mobility and Security, 20 December 2009 through 23 December 2009 ; 2009 ; 9781424462735 (ISBN) Khaledi, M. J ; Hemmatyar, A. M. A ; Rabiee, H. R ; Mousavi, S. M ; Khaledi, M. H ; Sharif University of Technology
    Abstract
    Mobility is one of the most challenging issues in mobile Ad-Hoc networks which has a significant impact on performance of network protocols. To cope with this issue, the protocol designers should be able to analyze the movement of mobile nodes in a particular wireless network. In this paper, a new framework called Mobility Analyzer has been introduced for analysis and recognition of mobility traces. At first, the Mobility Analyzer acquires some mobility traces collected by GPS or generated with mobility simulators; then it calculates some mobility metrics which represent the movement behavior of the mobile nodes; finally it attempts to classify mobility traces into particular mobility models... 

    A new configuration of switched reluctance motor for reducing the torque ripple

    , Article 2009 International Conference on Electric Power and Energy Conversion Systems, 10 November 2009 through 12 November 2009 ; 2009 ; 9789948427155 (ISBN) Sheikhi, A ; Oraee, H ; Kaboli, S ; Dorkhah, M. R ; Sharif University of Technology
    Abstract
    Switched reluctance motors (SRM) are one of the most reliable and cost effective motors and their applications are increasing in industry. However, it suffers from high level of torque ripple. In this paper, a new configuration for stator and rotor of SRM is presented. In the proposed method, a new saliency is developed to remove negative torque and therefore decrease torque ripple and acoustic noise, increase efficiency and as a result, expand speed range. The simulation results demonstrate that the new motor structure has a smooth torque profile with possibility to work at higher speed lower acoustic noise