Search for: decomposition
0.011 seconds
Total 474 records

    On double-star decomposition of graphs

    , Article Discussiones Mathematicae - Graph Theory ; Volume 37, Issue 3 , 2017 , Pages 835-840 ; 12343099 (ISSN) Akbari, S ; Haghi, S ; Maimani, H ; Seify, A ; Sharif University of Technology
    University of Zielona Gora  2017
    A tree containing exactly two non-pendant vertices is called a doublestar. A double-star with degree sequence (k1 +1, k2 +1, 1, ⋯ , 1) is denoted by Sk1,k2 . We study the edge-decomposition of graphs into double-stars. It was proved that every double-star of size k decomposes every 2k-regular graph. In this paper, we extend this result by showing that every graph in which every vertex has degree 2k + 1 or 2k + 2 and containing a 2-factor is decomposed into Sk1,k2 and Sk1-1,k2 , for all positive integers k1 and k2 such that k1 + k2 = k  

    Query point visibility computation in polygons with holes

    , Article Computational Geometry: Theory and Applications ; Volume 39, Issue 2 , 2008 , Pages 78-90 ; 09257721 (ISSN) Zarei, A ; Ghodsi, M ; Sharif University of Technology
    In this paper, we consider the problem of computing the visibility of a query point inside polygons with holes. The goal is to perform this computation efficiently per query considering the cost of the preprocessing phase. Our algorithm is based on solutions in [A.L.P. Bose, J.I. Munro, Efficient visibility queries in simple polygons, Computational Geometry: Theory and Applications 23 (3) (2002) 313-335] and [M.T.B. Aronov, L. Guibas, L. Zhang, Visibility queries and maintenance in simple polygons, Discrete and Computational Geometry 27 (4) (2002) 461-483] proposed for simple polygons. In our solution, the preprocessing is done in time O( n3logn) to construct a data structure of size O( n3).... 

    Commuting decompositions of complete graphs

    , Article Journal of Combinatorial Designs ; Volume 15, Issue 2 , 2007 , Pages 133-142 ; 10638539 (ISSN) Akbari, S ; Herman, A ; Sharif University of Technology
    We say that two graphs G and H with the same vertex set commute if their adjacency matrices commute. In this article, we show that for any natural number r, the complete multigraph Knr is decomposable into commuting perfect matchings if and only if n is a 2-power. Also, it is shown that the complete graph Kn is decomposable into commuting Hamilton cycles if and only if n is a prime number. © 2006 Wiley Periodicals, Inc  

    A mathematical model for prediction of austenite phase transformation

    , Article Materials Letters ; Volume 58, Issue 10 , 2004 , Pages 1597-1601 ; 0167577X (ISSN) Serajzadeh, S ; Sharif University of Technology
    In this study, a model is developed to predict austenite phase transformation by means of Avrami's model and the finite element method. For doing so, the Avrami-type rate equation is evaluated with the modified Euler's method to handle the kinetics of phase change under non-isothermal conditions. Also, to simultaneously consider the effect of temperature variations on austenite decomposition, heat conduction equation is solved using a two-dimensional finite element approach. To establish the reliability of theoretical results, a comparison is made between simulated and experimental cooling curves for two grades of carbon steel. © 2003 Elsevier B.V. All rights reserved  

    Surface balance laws of linear and angular momenta and Cauchy's stress theorem

    , Article Scientia Iranica ; Volume 11, Issue 1-2 , 2004 , Pages 21-25 ; 10263098 (ISSN) Nosier, A ; Yavari, A ; Sharif University of Technology
    Sharif University of Technology  2004
    Using Helmholtz's decomposition theorem, the laws of balance of linear and angular momenta are restated as surface integrals over the closed surface of an arbitrary subregion in a continuum. Newton's law of action and reaction and Cauchy's theorem for stress and couple-stress are proved as corollaries of these surface balance laws. © Sharif University of Technology  

    Optimal reliable operation of hydrothermal power systems with random unit outages

    , Article IEEE Transactions on Power Systems ; Volume 18, Issue 1 , 2003 , Pages 279-287 ; 08858950 (ISSN) Amjady, N ; Farrokhzad, D ; Modarres, M ; Sharif University of Technology
    A new model for long-term operation of hydrothermal power systems is introduced and a method for obtaining an optimal solution is also developed. We assume that reservoir inflows and energy demand are stochastic and all units are exposed to random outages. The objective is to minimize the total cost of the system as well as the expected interruption cost of energy (EIC) during a given planning horizon. This goal is reached through determination of hydroplant discharges, thermal units energy output, and the system reliability level simultaneously. In fact, we integrate long-term hydrothermal system operation planning and system reliability determination in a unified model. Since the resulting... 

    Interpolative coding of speech parameters using hierarchical temporal decomposition

    , Article Digital Signal Processing: A Review Journal ; Volume 13, Issue 3 , 2003 , Pages 433-456 ; 10512004 (ISSN) Ghaemmaghami, S ; Deriche, M ; Sridharan, S ; Sharif University of Technology
    Elsevier Inc  2003
    A new method for temporal decomposition (TD) of speech parameters for very low rate coding applications is developed. Unlike typical TD, the phonetic relevance is not considered here, instead, we represent the spectral parameters of speech using pre-defined interpolation functions. These functions are located at instants, which give maximum correlation with the true event structure. In this method, no event refinement is required, which significantly reduces the computational complexity of the coder to make real-time implementation possible. The method is also highly flexible and can comply with diverse coding system attributes such as bit-rate, accuracy, delay, and complexity. A spectral... 

    Optimal Reliable Operation of Hydrothermal Power Systems with Random Unit Outages

    , Article IEEE Power Engineering Review ; Volume 22, Issue 11 , 2002 , Pages 59- ; 02721724 (ISSN) Amjady, N ; Farrokhzad, D ; Modarres, M ; Sharif University of Technology
    A new model for long-term operation of hydrothermal power systems is introduced, and a method for obtaining an optimal solution is developed. We assume both reservoir inflows and energy demand are stochastic and all units are exposed to random outages. The objective is to minimize the total cost of the system as well as the expected interruption cost of energy (EIC) during a given planning horizon. This goal is reached through simultaneous determination of hydro plant discharges, thermal units energy output, and the system reliability level. Long-term hydrothermal system operation planning and system reliability determination are integrated in a unified model. Since the resulting model is a... 

    Quad-Tree decomposition method for areal upscaling of heterogeneous reservoirs: Application to arbitrary shaped reservoirs

    , Article Fuel ; Volume 139 , 2014 , Pages 659-670 ; 00162361 (ISSN) Gholinezhad, S ; Jamshidi, S ; Hajizadeh, A ; Sharif University of Technology
    In this paper, Quad-Tree decomposition method is applied for areal upscaling of irregular shaped petroleum reservoirs. Quad-Tree decomposition is a recursive data structuring technique which generates an upscaled model with non-uniform (unstructured) gridblocks. This type of coarsening reduces the number of gridblocks, but preserves the main heterogeneity features of the original fine model. Because of the quadruplet nature of the Quad-Tree decomposition, this method cannot be used for upscaling of irregular-shaped models, directly. In this study, by circumscribing a square to the irregular-shaped reservoirs, a temporary model is obtained which can be upscaled by Quad-Tree decomposition.... 

    The case for network functions decomposition

    , Article 17th ACM International Conference on emerging Networking EXperiments and Technologies, CoNEXT 2021, 7 December 2021 through 10 December 2021 ; 2021 , Pages 475-476 ; 9781450390989 (ISBN) Shahinfar, F ; Miano, S ; Sanaee, A ; Siracusano, G ; Bifulco, R ; Antichi, G ; ACM SIGCOMM ; Sharif University of Technology
    Association for Computing Machinery, Inc  2021
    This paper makes a case for writing unrestricted eBPF network functions which then get automatically decomposed between kernel and user-space. © 2021 Owner/Author  

    Noninvasive fetal ECG extraction using doubly constrained block-term decomposition

    , Article Mathematical Biosciences and Engineering ; Volume 17, Issue 1 , 2020 , Pages 144-159 Mousavian, I ; Shamsollahi, M. B ; Fatemizadeh, E ; Sharif University of Technology
    American Institute of Mathematical Sciences  2020
    Fetal electrocardiogram (fECG) monitoring is a beneficial method for assessing fetal health and diagnosing the fetal cardiac condition during pregnancy. In this study, an algorithm is proposed to extract fECG from maternal abdominal signals based on doubly constrained block-term (DoCoBT) tensor decomposition. This tensor decomposition method is constrained by quasi-periodicity constraints of fetal and maternal ECG signals. Tensor decompositions are more powerful tools than matrix decomposition, due to employing more information for source separation. Tensorizing abdominal signals and using periodicity constraints of fetal and maternal ECG, appropriately separates subspaces of the mother, the... 

    An empirical time-domain trend line-based bridge signal decomposing algorithm using Savitzky–Golay filter

    , Article Structural Control and Health Monitoring ; Volume 28, Issue 7 , 2021 ; 15452255 (ISSN) Kordestani, H ; Zhang, C ; Masri, S. F ; Shadabfar, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2021
    This paper develops a trend line-based algorithm for signal decomposition in which the adjusted Savitzky–Golay filter is utilized to initiate the decomposition process. In this line, the proposed algorithm determines some special trend lines, mainly composed of the natural frequency of a bridge. An easy-to-implement algorithm is then provided to formulate this process and to decompose the given signal into its components in a systematic way. Additionally, a residual signal is generated by the proposed algorithm to store the detected noise and to reconstruct the original signal. To verify the proposed algorithm in the field of bridge health monitoring, a set of numerical and experimental... 

    Strategies for protecting supply chain networks against facility and transportation disruptions: An improved Benders decomposition approach

    , Article Annals of Operations Research ; Volume 210, Issue 1 , 2013 , Pages 125-163 ; 02545330 (ISSN) Azad, N ; Saharidis, G. K. D ; Davoudpour, H ; Malekly, H ; Yektamaram, S. A ; Sharif University of Technology
    Disruptions rarely occur in supply chains, but their negative financial and technical impacts make the recovery process very slow. In this paper, we propose a capacitated supply chain network design (SCND) model under random disruptions both in facility and transportation, which seeks to determine the optimal location and types of distribution centers (DC) and also the best plan to assign customers to each opened DC. Unlike other studies in the extent literature, we use new concepts of reliability to model the strategic behavior of DCs and customers at the network: (1) Failure of DCs might be partial, i.e. a disrupted DC might still be able to serve with a portion of its initial capacity (2)... 

    Canonical polyadic decomposition of complex-valued multi-way arrays based on simultaneous schur decomposition

    , Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings ; 2013 , Pages 4178-4182 ; 15206149 (ISSN) ; 9781479903566 (ISBN) Sardouie, S. H ; Albera, L ; Shamsollahi, M. B ; Merlet, I ; Sharif University of Technology
    In this paper, we propose a new semi-algebraic algorithm to compute the Canonical Polyadic (CP) decomposition of complex-valued multi-way arrays. The proposed algorithm is based on the Simultaneous Schur Decomposition (SSD) of particular matrices derived from the array to process. This CP algorithm solves some convergence problems of classical iterative techniques and its identifiability assumptions are less restrictive than those of other semi-algebraic methods. We also propose a new Jacobi-like algorithm to calculate the SSD of several complex-valued matrices. Finally the usefulness of the proposed method is illustrated in the context of fluorescence spectroscopy and epileptic source... 

    A decomposition approach in network revenue management: Special case of hotel

    , Article Journal of Revenue and Pricing Management ; Volume 12, Issue 5 , 2013 , Pages 451-463 ; 14766930 (ISSN) Aslani, S ; Modarres, M ; Sibdari, S ; Sharif University of Technology
    In this article, we address the multiple-night stay hotel revenue management. Using a decomposition method, we transform the multiple-night stay revenue management into a single night. To this end, we define effective arrival rate for each night that is derived from all the booking requests that contain the night, excluding the possible 'customer losses'. A customer is labeled 'loss' either because of the existence of an expensive night in his itinerary or because of a stock-out occurrence over his stay. We calculate the probabilities of these two incidents and then update the effective daily arrival rate, accordingly. In this way, we can use the classical single-night revenue management,... 

    An approximation technique for jet impingement flow

    , Article AIP Conference Proceedings, 22 September 2014 through 28 September 2014 ; Volume 1648 , 2015 ; 0094243X (ISSN) ; 9780735412873 (ISBN) Najafi, M ; Fincher, D ; Taeibi Rahni, T ; Massah, H ; Javadi, K. H ; Sharif University of Technology
    American Institute of Physics Inc  2015
    The analytical approximate solution of a non-linear jet impingement flow model will be demonstrated. We will show that this is an improvement over the series approximation obtained via the Adomian decomposition method, which is itself, a powerful method for analysing non-linear differential equations. The results of these approximations will be compared to the Runge-Kutta approximation in order to demonstrate their validity  

    Ballistic and collisional flow contributions to anti-fourier heat transfer in rarefied cavity flow

    , Article Scientific Reports ; Volume 8, Issue 1 , 2018 ; 20452322 (ISSN) Akhlaghi, H ; Roohi, E ; Stefanov, S ; Sharif University of Technology
    This paper investigates anti-Fourier heat transfer phenomenon in a rarefied gas confined within a lid-driven cavity using a novel flow decomposition technique in the direct simulation Monte Carlo (DSMC) method proposed by Stefanov and co-workers. An isothermal cavity with different degrees of flow rarefaction from near continuum to mid transition regimes was considered to investigate cold-to-hot heat transfer from ballistic/collision flow decomposition viewpoint. A new cold-to-hot heat transfer indicator in the form of a scalar product of normalized heat flow vector and normalized temperature gradient vector has been introduced for the overall, ballistic and collision parts of these vectors.... 

    Brain waves evaluation of sound therapy in chronic subjective tinnitus cases using wavelet decomposition

    , Article Frontiers in Integrative Neuroscience ; Volume 12 , 2018 ; 16625145 (ISSN) Asadpour, A ; Jahed, M ; Mahmoudian, S ; Sharif University of Technology
    Frontiers Media S.A  2018
    Management and treatment of subjective tinnitus is an ongoing focus of research activities. One of the most viable assessments of such treatment is the evaluation of brain activity in addition to patient response and clinical assessment. This study focuses on sound therapy and evaluation of patients’ electroencephalogram (EEG) in order to verify the potency of this approach. Broadband sound therapy was applied to nineteen participants aging from 25 to 64 and suffering from chronic subjective tinnitus to study the difference of brain activity, a) before fake treatment, b) after fake treatment and c) after the main treatment, using EEG and Visual Analog Scale (VAS) for evaluating Residual... 

    Reduced access structures with four minimal qualified subsets on six participants

    , Article Advances in Mathematics of Communications ; Volume 12, Issue 1 , February , 2018 , Pages 199-214 ; 19305346 (ISSN) Gharahi, M ; Khazaei, S ; Sharif University of Technology
    American Institute of Mathematical Sciences  2018
    In this paper, we discuss a point about applying known decomposition techniques in their most general form. Three versions of these methods, which are useful for obtaining upper bounds on the optimal information ratios of access structures, are known as: Stinson’s λ-decomposition, (λ, ω)decomposition and λ-weighted-decomposition, where the latter two are generalizations of the first one. We continue by considering the problem of determining the exact values of the optimal information ratios of the reduced access structures with exactly four minimal qualified subsets on six participants, which remained unsolved in Martí-Farré et al.’s paper [Des. Codes Cryptogr. 61 (2011), 167-186]. We... 

    Superabsorbent polymer as nanoreactors for preparation of hematite nanoparticles and application of the prepared nanocatalyst for the friedel-crafts acylation

    , Article Journal of the Brazilian Chemical Society ; Volume 20, Issue 3 , 2009 , Pages 466-471 ; 01035053 (ISSN) Saeidian, H ; Moghaddam, F. M ; Pourjavadi, A ; Barzegar, S ; Soleyman, R ; Sohrabi, A ; Sharif University of Technology
    The synthesis of pure α-Fe2O3 nanoparticles (30 nm) using a superabsorbent nanopolymer (SANP) by the thermal decomposition is reported. Synthesized α-Fe2O3 nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electronic microscopy (TEM) and thermogravimetric analysis (TG) techniques. The applicability of this nanostructure material was assessed by its catalytic effect on the Friedel-Crafts acylation. ©2009 Sociedade Brasileira de Química