Search for: new-approaches
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    Steganography in silence intervals of speech

    , Article 2008 4th International Conference on Intelligent Information Hiding and Multiedia Signal Processing, IIH-MSP 2008, Harbin, 15 August 2008 through 17 August 2008 ; 2008 , Pages 605-607 ; 9780769532783 (ISBN) Shirali Shahreza, S ; Shirali Shahreza, M ; Sharif University of Technology
    This paper presents a new approach for hiding information in speech signals. In this method, the silence intervals of speech are found and the length (number of samples) of these intervals is changed to hide information. This method can be used simultaneously with other methods. © 2008 IEEE  

    A new approach to model sensitivity of graphene-based gas sensors

    , Article Semiconductor Science and Technology ; Volume 30, Issue 4 , March , 2015 ; 02681242 (ISSN) Ghadiry, M ; Ismail, R ; Naraghi, B ; Taheri Abed, S ; Kavosi, D ; Fotovatikhah, F ; Sharif University of Technology
    Institute of Physics Publishing  2015
    Carbon-based sensors are attractive because of their excellent sensing capability. In this paper, we propose a new approach to analytically model the sensitivity of these devices based on graphene. The model relies on the surface potential and current of the device. For the first time, we included ionization in the modelling and examined the importance of this effect. In order to validate the model, the results are compared with experimental data from a fabricated device  

    Performing assembly-based method engineering by architecture-centric method engineering approach

    , Article EMS 2008, European Modelling Symposium, 2nd UKSim European Symposium on Computer Modelling and Simulation, Liverpool, 8 September 2008 through 10 September 2008 ; 2008 , Pages 181-186 ; 9780769533254 (ISBN) Ahmadi, H ; Rashidi, H ; Moaven, S ; Habibi, J ; Sharif University of Technology
    Due to the necessity for methods that are able to handle complexities of systems, use of Method Engineering (ME) to construct more adaptable and flexible methods has become of importance. Assemblybased approach is the most well-known approach of ME that performs method construction by reusing and assembling different method fragments. This approach, like other approaches of ME, suffers from the lack of suitable guidelines. In this way, architecture-centric method engineering (ArCME) is a new approach which aims at performing ME processes in a more disciplined and cohesive way. In this paper, process of assemblybased ME is enhanced by ArCME. Furthermore, benefits of implementing the process... 

    A new approach to assembly level programming

    , Article EUROCON 2007 - The International Conference on Computer as a Tool, Warsaw, 9 September 2007 through 12 September 2007 ; December , 2007 , Pages 439-445 ; 142440813X (ISBN); 9781424408139 (ISBN) Sahraeian, M. E ; Vosoughi Vahdat, B ; Sharif University of Technology
    In assembly level programming we need to know the mnemonic of each assembly instruction. But it is not so easy to remember mnemonics of all instructions, while the instruction set of Pentium processor includes 280 instructions. In this paper we introduce a new programming approach to assembly level programming in which most important assembly instructions (about 100 instructions) can be substituted for simple equivalents. These equivalent instructions are based on simple familiar operators and make a large simplification in assembly programming. This new language has a free format structure and hence is called Free Format Assembly Language. Evaluating the performance of this language using a... 

    Total fuel reduction via formation flights: a new approach to air-corridor path optimization

    , Article AIAA AVIATION 2014 -14th AIAA Aviation Technology, Integration, and Operations Conference ; 2014 Asadi, F ; Malaek, S. M. B ; Sharif University of Technology
    This paper presents a new approach to better utilize international air-corridors for formation flights. Using Particle Swarm Optimization, we show how different long-range flights can be brought together to form a formation. The idea serves both to increase international air-corridor capacities together and to decrease fuel consumption up to 8-10%. Case studies show that there are many places which such an approach could effectively be implemented to help cope with increase in fuel price as well as the demand for aerial transport of passengers and goods  

    Non-hydrostatic layered flows over a sill

    , Article Fluid Dynamics Research ; Volume 45, Issue 2 , February , 2013 ; 01695983 (ISSN) Jamali, M ; Sharif University of Technology
    This work takes a new approach to solving non-hydrostatic equations of layered flows over bottom topography. A perturbation technique is used to find explicit expressions for a flow for different regimes of single- and two-layer flows over a sill. Excellent agreement with previous solutions and experimental data is obtained, and more details of the non-hydrostatic flow over a sill are revealed. The proposed method is simple and compact and removes the need for complex numerical techniques to solve the non-hydrostatic equations. It is shown that in the approach-controlled regime of two-layer flow over a sill, the flow upstream and farther downstream the sill crest can be described by the... 

    Heteroscedastic multilinear discriminant analysis for face recognition

    , Article Proceedings - International Conference on Pattern Recognition, 23 August 2010 through 26 August 2010, Istanbul ; 2010 , Pages 4287-4290 ; 10514651 (ISSN) ; 9780769541099 (ISBN) Safayani, M ; Manzuri Shalmani, M. T ; Sharif University of Technology
    There is a growing attention in subspace learning using tensor-based approaches in high dimensional spaces. In this paper we first indicate that these methods suffer from the Heteroscedastic problem and then propose a new approach called Heteroscedastic Multilinear Discriminant Analysis (HMDA). Our method can solve this problem by utilizing the pairwise chernoff distance between every pair of clusters with the same index in different classes. We also show that our method is a general form of Multilinear Discriminant Analysis (MDA) approach. Experimental results on CMU-PIE, AR and AT&T face databases demonstrate that the proposed method always perform better than MDA in term of classification... 

    Design, dynamic analysis and optimization of a Rover for rescue operations

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 4020 LNAI , 2006 , Pages 290-300 ; 03029743 (ISSN); 9783540354376 (ISBN) Tavakoli Nia, H ; Alemohammad, S. H ; Bagheri, S ; Khiabani', R. H ; Meghdari, A ; Sharif University of Technology
    Springer Verlag  2006
    In this paper a new approach to dynamic optimization of a rough terrain rover is introduced. Since rover wheels traction has a significant role in rover mobility, optimization is based on the minimization of traction at rover wheel-ground interfaces. The method of optimization chosen is Genetic Algorithm (GA) which is a directed random search technique along with the usual optimization based on directional derivatives. GA is a suitable and efficient method of optimization for nonlinear problems. The procedure is applied on a specific rough terrain rover called CEDRA-I Shrimp Rover. The present work resulted in design and manufacturing of the optimized rover called CEDRA-II Shrimp Rover. ©... 

    Prediction of the noise spectrum in optoelectronic oscillators: An analytical conversion matrix approach

    , Article Journal of the Optical Society of America B: Optical Physics ; Vol. 31, issue. 8 , August , 2014 , p. 1915-1925 ; ISSN: 07403224 Jahanbakht, S ; Hosseini, S. E ; Banai, A ; Sharif University of Technology
    In this paper an analytical formulation based on the conversion matrix approach for characterizing the oscillator noise spectra as well as the phase and amplitude noise spectra for a single-loop optoelectronic oscillator (OEO) is presented. The validity of this approach is verified by comparing our results regarding the noise spectra of the OEO against the results of two references in the literature. The first reference presents simulation results, and the second reference presents both simulation and measurement results, and good agreement is seen between the results of the new method and those of the references. The advantage of the new approach is the simplicity of the theory as well as... 

    Probabilistic optimal power flow in correlated hybrid wind-PV power systems: A review and a new approach

    , Article Renewable and Sustainable Energy Reviews ; Vol. 41 , 2014 , pp. 1437-1446 ; ISSN: 13640321 Aien, M ; Rashidinejad, M ; Firuz-Abad, M. F ; Sharif University of Technology
    Hastening the power industry reregulation juxtaposed with the unprecedented utilization of uncertain renewable energies (REs), faces power system operation with sever uncertainties. Consequently, uncertainty assessment of system performance is an obligation. This paper reviews the probabilistic techniques used for probabilistic optimal power flow (P-OPF) studies and proposes a novel and powerful approach using the unscented transformation (UT) method. The heart of the proposed method lies in how to produce the sampling points. Appropriate sampling points are chosen to perform the P-OPF with a high degree of accuracy and less computational burden compared with features of other existing... 

    Wind farm layout optimization using imperialist competitive algorithm

    , Article Journal of Renewable and Sustainable Energy ; Vol. 6, Issue. 4 , July , 2014 ; ISSN: 19417012 Kiamehr, K ; Hannani, S. K ; Sharif University of Technology
    In this work, the wind farm layout optimization problem is dealt with using a new approach. The aim of wind farm layout optimization is to maximize the output power of a wind farm considering the wake losses. Layout optimization minimizes the wake losses regarding the location of the turbines. Three different wind scenarios with different wind direction angles, wind direction blowing probabilities, and Weibull distribution parameters are assumed. Since, the problem is nonlinear and constrained, imperialist competitive algorithm is used as a modern and powerful algorithm for continuous optimization problems. The optimization outcomes indicate that imperialist competitive algorithm yields... 

    Linear array thinning using iterative FFT plus soft decision

    , Article Proceedings International Radar Symposium, Dresden ; Volume 1 , June , 2013 , Pages 301-306 ; 21555753 (ISSN) ; 9783954042234 (ISBN) Tohidi, E ; Sebt, M. A ; Nayebi, M. M ; Sharif University of Technology
    Array Thinning is the procedure of reducing the number of elements in such a way that leads to low sidelobe level and narrow beamwidth. Main motivations of array thinning are reduction in weight and cost of antennas array. W.P.M.N. Keizer has presented a new approach for the synthesis of thinned uniformly spaced linear arrays featuring a minimum sidelobe level. The method is based on the iterative Fourier technique to derive element excitations from the prescribed array factor using successive forward and backward Fourier transforms. Array thinning is accomplished by setting the amplitudes of the largest element excitations to unity and the others to zero during each iteration cycle. In this... 

    Unsupervised approach to extract summary keywords in meeting domain

    , Article 2015 23rd European Signal Processing Conference, EUSIPCO 2015, 31 August 2015 through 4 September 2015 ; August , 2015 , Pages 1406-1410 ; 9780992862633 (ISBN) Bokaetf, M. H ; Sameti, H ; Liu, Y ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Summary keywords are words that are used in the reference extracted summary, therefore can be used to discriminate between summary sentences from non-summary ones. Finding these words is important for the extractive summarization algorithms that measure the importance of a sentence based on the importance of its constituent words. This paper is focused on extracting summary keywords in the multi-party meeting domain. We test previously proposed keyword extraction algorithms and evaluate their performance to determine summary keywords. We also propose a new approach which uses discourse information to find local important keywords and show that it outperforms all the previous methods. We... 

    Adaptive integrated guidance and fault tolerant control using backstepping and sliding mode

    , Article International Journal of Aerospace Engineering ; Volume 2015 , September , 2015 ; 16875966 (ISSN) Jegarkandi, M. F ; Ashrafifar, A ; Mohsenipour, R ; Sharif University of Technology
    Hindawi Publishing Corporation  2015
    A new method of integrated guidance and control for homing missiles with actuator fault against manoeuvring targets is proposed. Model of the integrated guidance and control system in the pitch plane with actuator fault and some uncertainty is developed. A control law using combination of adaptive backstepping and sliding mode approaches is designed to achieve interception in the presence of bounded uncertainties and actuator fault. Simulation results show that new approach has better performance than adaptive backstepping and has good performance in the presence of actuator fault  

    TTCN: A new approach for low-power split-row LDPC decoders

    , Article Proceedings - IEEE International Symposium on Circuits and Systems, 24 May 2015 through 27 May 2015 ; Volume 2015-July , 2015 , Pages 2001-2004 ; 02714310 (ISSN) ; 9781479983919 (ISBN) Shahrad, M ; Shabany, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Split-Row technique is proved to be one of the most effective methods to reduce the routing complexity of fully-parallel LDPC decoders. This technique is based on the idea of splitting each check node processor to multiple smaller processors. This paper introduces a new method, to increase the power-efficiency of Split-Row LDPC decoders. The proposed method is called trust to the truthful check node (TTCN), enabling the decoder to only depend on a portion of check node processors at specific decoding iterations. This leads to an average reduction of 30%-40% in the check node dynamic power consumption. This is achieved by means of trust to a minority of check node processors and gating the... 

    Recursive sensor placement in two dimensional TDOA based localization

    , Article 24th Iranian Conference on Electrical Engineering, 10 May 2016 through 12 May 2016 ; 2016 , Pages 300-304 ; 9781467387897 (ISBN) Hamdollahzadeh, M ; Adelipour, S ; Behnia, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    This paper presents a new approach to sensor placement strategy in emitter localization problem which is based on Time Difference of Arrival (TDOA) measurements. The advantage of this method is its flexibility and capability of positioning sensors in constrained or non-stationary situations in which the positions of the sensors are restricted to certain portions of the space and/or needed to be changed repeatedly. The validity of the proposed algorithm is assessed by three different simulation scenarios and the results verify its proper operation  

    Unsupervised cross-subject BCI learning and classification using riemannian geometry

    , Article 24th European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning, ESANN 2016, 27 April 2016 through 29 April 2016 ; 2016 , Pages 307-312 ; 9782875870278 (ISBN) Nasiri Ghosheh Bolagh, S ; Shamsollahi, M. B ; Jutten, C ; Congedo, M ; Sharif University of Technology
    i6doc.com publication  2016
    The inter-subject variability poses a challenge in cross-subject Brain-Computer Interface learning and classification. As a matter of fact, in cross-subject learning not all available subjects may improve the performance on a test subject. In order to address this problem we propose a subject selection algorithm and we investigate the use of this algorithm in the Riemannian geometry classification framework. We demonstrate that this new approach can significantly improve cross-subject learning without the need of any labeled data from test subjects  

    A path-based broadcast algorithm for wormhole hypercubes

    , Article I-SPAN 2009 - The 10th International Symposium on Pervasive Systems, Algorithms, and Networks, 14 December 2009 through 16 December 2009, Kaohsiung ; 2009 , Pages 586-591 ; 9780769539089 (ISBN) Nazi, A ; Sarbazi Azad, H ; Sharif University of Technology
    When implementing some applications in multi-computer systems, broadcast operation is a necessity for efficient communication. Several broadcast algorithms have been proposed in the literature for hypercube networks. In this paper, we evaluate the performance of broadcast routing algorithms for hypercube networks, and propose a new approach by reducing the number of steps required to perform. © 2009 IEEE  

    Polar code-based secure channel coding scheme with small key size

    , Article IET Communications ; Volume 11, Issue 15 , 2017 , Pages 2357-2361 ; 17518628 (ISSN) Hooshmand, R ; Aref, M. R ; Sharif University of Technology
    In this study, the secret polar encoding and secret successive cancellation decoding algorithms are introduced; with these algorithms, secure and efficient communication can be enhanced between the honest parties. Also, the key size of the proposed polar code-based secure channel coding system is reduced significantly compared to the existing systems. To decrease the key size, the authors employ the three following methods: (i) a new approach is proposed to save some bit-channel indices instead of saving the generator matrix of the used polar code; (ii) the permutation and scrambling matrices are not used in this scheme; and (iii) by the help of the properties of polar codes, it does not... 

    Spatial integration by a dielectric slab and its planar graphene-based counterpart

    , Article Optics Letters ; Volume 42, Issue 10 , 2017 , Pages 1954-1957 ; 01469592 (ISSN) Zangeneh Nejad, F ; Khavasi, A ; Sharif University of Technology
    In this contribution a new approach to perform spatial integration is presented using a dielectric slab. Our approach is indeed based on the fact that the transmission coefficient of a simple dielectric slab at its mode excitation angle matches the Fourier-Green's function of first-order integration. Inspired by the mentioned dielectric-based integrator, we further demonstrate its graphene-based counterpart. The latter is not only reconfigurable but also highly miniaturized in contrast to the previously reported designs [Opt. Commun. 338, 457 (2015)]. Such integrators have the potential to be used in ultrafast analog computation and signal processing. © 2017 Optical Society of America