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    Wyświetlanie 1-55 z 55
    Tytuł:
    Preconditioned Conjugate Gradient Method for Solution of Large Finite Element Problems on CPU and GPU
    Autorzy:
    Fialko, S. Y.
    Zeglen, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/307602.pdf
    Data publikacji:
    2016
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    conjugate gradient
    incomplete Cholesky factorization
    iterative solvers
    NVIDIA CUDA
    preconditioned conjugate gradient
    Opis:
    In this article the preconditioned conjugate gradient (PCG) method, realized on GPU and intended to solution of large finite element problems of structural mechanics, is considered. The mathematical formulation of problem results in solution of linear equation sets with sparse symmetrical positive definite matrices. The authors use incomplete Cholesky factorization by value approach, based on technique of sparse matrices, for creation of efficient preconditioning, which ensures a stable convergence for weakly conditioned problems mentioned above. The research focuses on realization of PCG solver on GPU with using of CUBLAS and CUSPARSE libraries. Taking into account a restricted amount of GPU core memory, the efficiency and reliability of GPU PCG solver are checked and these factors are compared with data obtained with using of CPU version of this solver, working on large amount of RAM. The real-life large problems, taken from SCAD Soft collection, are considered for such a comparison.
    Źródło:
    Journal of Telecommunications and Information Technology; 2016, 2; 26-33
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Salomons Theorem for polynomials with several parameters
    Autorzy:
    Frontczak, Maria
    Skibiński, Przemysław
    Spodzieja, Stanisław
    Powiązania:
    https://bibliotekanauki.pl/articles/965925.pdf
    Data publikacji:
    1999
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    conjugate polynomials
    decomposition of polynomials
    Źródło:
    Colloquium Mathematicum; 1999, 80, 1; 107-114
    0010-1354
    Pojawia się w:
    Colloquium Mathematicum
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling of a Large Rotary Heat Exchanger
    Autorzy:
    Tulwin, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/118115.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Promocji Wiedzy
    Tematy:
    CFD
    Conjugate
    Heat
    Exchanger
    Recuperation
    Opis:
    The first simulation consists of a partial cut-out of gas flow canal between the heat exchanger fins. The simulation is steady state and mainly provides the information about the heat transfer coefficient and pressure drop across the canal. The second simulation takes into account the complete system of rotary heat exchanger. It is a transient simulation with moving mesh. Then the heat transfer and air flow parameters are presented as a porous volume with a heat transfer model and rotational multi zone interface conditions. This simplification is accurate providing much better performance as the number of mesh nodes is much smaller. The methodology of the model setup is presented.
    Źródło:
    Applied Computer Science; 2017, 13, 1; 20-28
    1895-3735
    Pojawia się w:
    Applied Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and biological activity of raltitrexed-carrier conjugates
    Autorzy:
    Jagiello, Monika
    Kanska, Urszula
    Nevozhay, Dmitry
    Boratynski, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1040427.pdf
    Data publikacji:
    2010
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    raltitrexed
    tomudex
    carrier
    conjugate
    thymidylate synthase
    Opis:
    Drugs used in chemotherapy give undesirable side effects, e.g., cardiotoxicity, leucopenia, hair loss and others. Covalent binding of a drug with a carrier may change its biodistribution, elimination and/or rate of transformation in the organism. The aim of this work was to synthesize conjugates of anticancer drug - raltitrexed (RTX) with lysozyme, bovine serum albumin (BSA), and dextran T40 and to investigate their cytotoxicity and influence on the cell cycle in comparison with the free drug. Before conjugation RTX was transformed into anhydride by treatment with dicyclohexylcarbodiimide in dimethylformamide. Activated RTX was added into aqueous solution of carriers at different pH (from 8.5 to 10.5) for 3 to 15 min. The reaction was stopped by reducing the pH to 7.0. Maximum yield of the reaction was obtained at pH 10 for BSA as well as for dextran. The highest level of substitution was obtained after 5 min of the reaction. In in vitro experiments on three cell lines: SW707, LoVo and A549, all conjugates tested had up to a few hundred times higher IC50 than the free drug. Interestingly, it was noticed that the conjugates based on dextran and albumin were more cytotoxic than the free drug in the highest concentrations tested (1000 and 10000 ng/ml). The influence of RTX and the conjugates on SW707 cell cycle was studied. RTX blocked the cell cycle mostly in the G0-G1 and S phase and increased the percentage of apoptotic cells. Cells in the G2-M phase were not observed. The conjugates blocked the cell cycle in the S phase and decreased the percentage of cells in the G0-G1 phase.
    Źródło:
    Acta Biochimica Polonica; 2010, 57, 1; 83-87
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Purification and functional reconstitution of intact ral-binding GTPase activating protein, RLIP76, in artificial liposomes.
    Autorzy:
    Singhal, Sharad
    Singhal, Jyotsana
    Cheng, JiZhong
    Pikuła, Sławomir
    Sharma, Rajendra
    Zimniak, Piotr
    Awasthi, Yogesh
    Awasthi, Sanjay
    Powiązania:
    https://bibliotekanauki.pl/articles/1044153.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    RLIP76
    glutathione-conjugate
    anthracycline
    transport
    proteolysis
    Opis:
    We have recently shown that RLIP76, a ral-binding GTPase activating protein, mediates ATP-dependent transport of glutathione-conjugates (GS-E) and doxorubicin (DOX) (S. Awasthi et al., Biochemistry 39, 9327, 2000). Transport function of RLIP76 was found to be intact despite considerable proteolytic fragmentation in preparations used for those studies, suggesting either that the residual intact RLIP76 was responsible for transport activity, or that the transport activity could be reconstituted by fragments of RLIP76. If the former were true, intact RLIP76 would have a much higher specific activity for ATP-hydrolysis than the fragmented protein. We have addressed this question by comparing transport properties of recombinant RLIP76 and human erythrocyte membrane RLIP76 purified in buffers treated with either 100 or 500 μM serine protease inhibitor, PMSF. The purity and identity of recombinant and human erythrocyte RLIP76 was established by SDS/PAGE and Western-blot analysis. These studies confirmed the origin of the 38 kDa protein, previously referred to as DNP-SG ATPase, from RLIP76. Higher PMSF concentration resulted in lower yield of the 38 kDa band and higher yield of intact RLIP76 from both human and recombinant source. In contrast, the substrate-stimulated ATPase activity in presence of DNP-SG, doxorubicin, daunorubicin, or colchicine were unaffected by increased PMSF; similarly, ATP-dependent transport of doxorubicin in proteoliposomes reconstituted with RLIP76 was unaffected by higher PMSF. These results indicated that limited proteolysis by serine proteases does not abrogate the transport function of RLIP76. Comparison of transport kinetics for daunorubicin between recombinant vs human erythrocyte RLIP76 revealed higher specific activity of transport for tissue purified RLIP76, indicating that additional factors present in tissue purified RLIP76 can modulate its transport activity.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 2; 551-562
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conjugate priors for exponential-type processes with random initial conditions
    Autorzy:
    Magiera, Ryszard
    Powiązania:
    https://bibliotekanauki.pl/articles/1340503.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    conjugate prior
    stopping time
    exponential-type process
    Opis:
    The family of proper conjugate priors is characterized in a general exponential model for stochastic processes which may start from a random state and/or time.
    Źródło:
    Applicationes Mathematicae; 1993-1995, 22, 3; 321-330
    1233-7234
    Pojawia się w:
    Applicationes Mathematicae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Low generation polyamidoamine dendrimers (PAMAM) and biotinPAMAM conjugate – the detailed structural studies by 1 H and 13C nuclear magnetic resonance spectroscopy
    Autorzy:
    Wróbel, Konrad
    Wołowiec, Stanisław
    Powiązania:
    https://bibliotekanauki.pl/articles/2040134.pdf
    Data publikacji:
    2020-12-30
    Wydawca:
    Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
    Tematy:
    biotin conjugate
    nuclear magnetic resonance polyamidoamine dendrimer
    Opis:
    Introduction. The concept of targeted drug delivery is nowadays based on nanoparticle transporters. Such drug delivery systems for cancer cells should follow the requirements like: efficient drug release, selective binding and internalization to cancer cells. The anticancer drug selectivity can be achieved by attachment of cancer cell-recognizing molecules, like biotin. Among nanosized carriers the PAMAM dendrimers are tested intensely, especially they can be modified by covalent attachment of prodrug molecules and biotin as targeting molecule. Aim. We aimed at construction and characterization of a conjugate formed between PAMAM and biotin (Biot). The nuclear magnetic resonances is powerful tool to determine both the structure and stoichiometry of the conjugate. Material and methods. PAMAM G0 has been synthesized and functionalized with biotin by reaction with N-hydroxysuccinimide ester of biotin to obtain G0 double-substituted with biotin. All the compound were thoroughly characterized by the NMR spectroscopy. Results. The conjugate of PAMAM G0 dendrimer with two amide-bonded biotin molecules was obtained and fully characterized by NMR spectroscopy. Conclusion. N-hydroxysuccinimide ester of biotin spontaneously reacts with PAMAM G0 to obtain the conjugate of 2:1 biotin:G0 stoichiometry. The latter was designed as a targeting molecule in formation of megameric multidrug delivery system.
    Źródło:
    European Journal of Clinical and Experimental Medicine; 2020, 4; 281-285
    2544-2406
    2544-1361
    Pojawia się w:
    European Journal of Clinical and Experimental Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Curvatures of single-input control systems
    Autorzy:
    Jakubczyk, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/970753.pdf
    Data publikacji:
    2009
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    control system
    curvature
    invariants
    variational equation
    conjugate point
    Opis:
    We introduce invariants of control-affine systems which we call curvatures. They are defined by the drift and the control distribution, given by the system. The curvatures allow us to analyse the variational equation along a given trajectory, as well as existence of conjugate points.
    Źródło:
    Control and Cybernetics; 2009, 38, 4B; 1375-1391
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transport functions and physiological significance of 76 kDa Ral-binding GTPase activating protein (RLIP76).
    Autorzy:
    Awasthi, Sanjay
    Sharma, Rajendra
    Yang, Yusong
    Singhal, Sharad
    Pikula, Slawomir
    Bandorowicz-Pikula, Joanna
    Singh, Shivendra
    Zimniak, Piotr
    Awasthi, Yogesh
    Powiązania:
    https://bibliotekanauki.pl/articles/1043688.pdf
    Data publikacji:
    2002
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    RLIP76
    RalBP1
    glutathione conjugate
    multidrug resistance
    transport
    Opis:
    We have recently demonstrated that a previously known Ral-binding GTPase activating protein, RLIP76, can also catalyze ATP-dependent transport of various structurally unrelated xeno- and endobiotics irrespective of their net charge (Awasthi et al., 2000, Biochemistry, 39: 9327). RLIP76 is a non-ATP binding cassette (ABC) protein but it has two ATP-binding sites and shows basal ATPase activity which is stimulated in the presence of its transport substrates (allocrites) such as doxorubicin (DOX) and S-(2,4-dinitrophenyl) glutathione (DNP-SG). Proteoliposomes reconstituted with purified RLIP76 catalyze ATP-dependent, saturable transport of DOX, as well as of glutathione-conjugates including leukotrienes (LTC4) and the GSH-conjugate of 4-hydroxynonenal (GS-HNE). In erythrocytes the majority of transport activity for DOX, GS-HNE, and LTC4 is accounted for by RLIP76. Cells exposed to mild oxidative stress show a rapid and transient induction of RLIP76 resulting in an increased efflux of GS-HNE and acquire resistance to oxidative stress mediated toxicity and apoptosis. Cells transfected with RLIP76 acquire resistance to DOX through increased efflux of the drug suggesting its possible role in the mechanisms of drug-resistance. In this article, we discuss the significance of transport functions of RLIP76 highlighting its role in the defense mechanisms against oxidative injury, and modulation of signaling mechanisms.
    Źródło:
    Acta Biochimica Polonica; 2002, 49, 4; 855-867
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Geometric optimal control and two-level dissipative quantum systems
    Autorzy:
    Bonnard, B.
    Sugny, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/970909.pdf
    Data publikacji:
    2009
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    optimal control theory
    conjugate and cut loci
    quantum mechanics
    Opis:
    The objective of this article is to present techniques of geometric time-optimal control developed to analyze the control of two-level dissipative quantum systems. Combined with numerical simulations they allow to compute the time-minimal control using a shooting method. The robustness with respect to initial conditions and dissipative parameters is also analyzed using a continuation method.
    Źródło:
    Control and Cybernetics; 2009, 38, 4A; 1053-1080
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the approximation of conjugate functions from \(L^{p}\) by some special matrix means of conjugate Fourier series
    Autorzy:
    Krantz, Radosława
    Rzepka, Aleksandra
    Powiązania:
    https://bibliotekanauki.pl/articles/746463.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Matematyczne
    Tematy:
    degree of approximation
    Fourier series
    matrix means
    conjugate function
    Opis:
    The results corresponding to some theorems of W. Łenski and B. Szal are shown. From the presented pointwise results the estimates on norm approximation are derived. Some special cases as corollaries are also formulated.
    Źródło:
    Commentationes Mathematicae; 2014, 54, 2
    0373-8299
    Pojawia się w:
    Commentationes Mathematicae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Generalized ordered linear regression with regularization
    Autorzy:
    Łęski, J.
    Henzel, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/201591.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    linear regression
    IRLS
    OWA
    conjugate gradient optimization
    robust methods
    Opis:
    Linear regression analysis has become a fundamental tool in experimental sciences. We propose a new method for parameter estimation in linear models. The 'Generalized Ordered Linear Regression with Regularization' (GOLRR) uses various loss functions (including the o-insensitive ones), ordered weighted averaging of the residuals, and regularization. The algorithm consists in solving a sequence of weighted quadratic minimization problems where the weights used for the next iteration depend not only on the values but also on the order of the model residuals obtained for the current iteration. Such regression problem may be transformed into the iterative reweighted least squares scenario. The conjugate gradient algorithm is used to minimize the proposed criterion function. Finally, numerical examples are given to demonstrate the validity of the method proposed.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 3; 481-489
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Hartogs-type series for harmonic functions on Hartogs domains in $ℝ^n × ℝ^m$, m ≥ 2
    Autorzy:
    Ligocka, Ewa
    Powiązania:
    https://bibliotekanauki.pl/articles/1294106.pdf
    Data publikacji:
    1999
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    harmonic functions
    harmonic polynomials
    spherical harmonics
    conjugate harmonic functions
    Opis:
    We study series expansions for harmonic functions analogous to Hartogs series for holomorphic functions. We apply them to study conjugate harmonic functions and the space of square integrable harmonic functions.
    Źródło:
    Annales Polonici Mathematici; 1999, 71, 2; 151-160
    0066-2216
    Pojawia się w:
    Annales Polonici Mathematici
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On approach regions for the conjugate Poisson integral and singular integrals
    Autorzy:
    Ferrando, S.
    Jones, R.
    Reinhold, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1287340.pdf
    Data publikacji:
    1996
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    cone condition
    conjugate Poisson integral
    singular integrals
    ergodic Hilbert transform
    Opis:
    Let ũ denote the conjugate Poisson integral of a function $f ∈ L^{p}(ℝ)$. We give conditions on a region Ω so that $lim_{(v,ε)→(0,0)}_{(v,ε)∈Ω} ũ(x+v,ε) = Hf(x)$, the Hilbert transform of f at x, for a.e. x. We also consider more general Calderón-Zygmund singular integrals and give conditions on a set Ω so that $sup_{(v,r)∈Ω} |ʃ_{|t|>r} k(x+v-t)f(t)dt|$ is a bounded operator on $L^p$, 1 < p < ∞, and is weak (1,1).
    Źródło:
    Studia Mathematica; 1996, 120, 2; 169-182
    0039-3223
    Pojawia się w:
    Studia Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Iteratively reweighted least squares classifier and its l2- and l1-regularized Kernel versions
    Autorzy:
    Łęski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/199904.pdf
    Data publikacji:
    2010
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    classifier design
    IRLS
    conjugate gradient optimization
    gradient projection
    Kernel matrix
    Opis:
    This paper introduces a new classifier design method based on regularized iteratively reweighted least squares criterion function. The proposed method uses various approximations of misclassification error, including: linear, sigmoidal, Huber and logarithmic. Using the represented theorem a kernel version of classifier design method is introduced. The conjugate gradient algorithm is used to minimize the proposed criterion function. Furthermore, .1-regularized kernel version of the classifier is introduced. In this case, the gradient projection is used to optimize the criterion function. Finally, an extensive experimental analysis on 14 benchmark datasets is given to demonstrate the validity of the introduced methods.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 1; 171-182
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Efficient Iterative Detection Based on Conjugate Gradient and Successive Over-Relaxation Methods for Uplink Massive MIMO Systems
    Autorzy:
    Labed, Smail
    Aounallah, Naceur
    Powiązania:
    https://bibliotekanauki.pl/articles/24200730.pdf
    Data publikacji:
    2023
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    computational complexity
    conjugate gradient
    massive MIMO
    relaxation parameter
    signal detection
    Opis:
    Being a crucial aspect of fifth-generation (5G) mobile communications systems, massively multiple-input multipleoutput (mMIMO) architectures are expected to help achieve the highest key performance indicators. However, the huge numbers of antennas used in such systems make it difficult to determine the inversion of the signal channel matrix relied upon by several detection methods, hence posing a problem with accurate estimation of the symbols sent. In this paper, conjugate gradient (CG) and successive over-relaxation (SOR) methods are selected to construct a new iterative approach that avoids the matrix inversion computation issue. This suggested approach for uplink mMIMO detection is based on a joint cascade structure of both iterative methods. The CG method is first applied and adjusted for the initial solution, followed by the SOR method in the final iterations for terminal computations, resulting in an algorithm with robust performance and low computational complexity. Furthermore, the new hybrid scheme operates based on the relaxation parameter, whose value has a great impact on error performance and, whose optimal determination is necessary. Numerical simulations reveal that the proposed scheme is capable of significantly improving signal detection accuracy with minimum complexity. The simulation results indicated that the proposed detector outperforms CG and SOR detectors, achieves close to optimal performance, requires fewer iterations, and reduces complexity.
    Źródło:
    Journal of Telecommunications and Information Technology; 2023, 2; 1--9
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling and simulation of fluid flow and heat processes in a regenerator with ceramic chimney block checker work
    Autorzy:
    Zashkowa, L.
    Penkova, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/1965142.pdf
    Data publikacji:
    2005
    Wydawca:
    Politechnika Gdańska
    Tematy:
    glass furnace regenerator
    modelling
    simulation
    FEM
    conjugate heat transfer
    cyclic equilibrium
    Opis:
    Selected results of mathematical modelling and computer simulation of fluid flow and heat transfer processes in a glass furnace regenerator are reported. The conjugate heat transfer problem is solved in 3D using the ANSYS 8.0/FLOTRAN programme. The regenerator's geometry, finite element mesh, thermal loads and boundary conditions are presented. The momentum, continuity and energy equations are solved.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 133-142
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The degree of approximation by Hausdorff means of a conjugate Fourier series
    Autorzy:
    Kęska, Sergiusz
    Powiązania:
    https://bibliotekanauki.pl/articles/747041.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
    Tematy:
    Hausdorff matrix
    conjugate series of the Fourier series
    degree of approximation
    Opis:
    The purpose of this paper is to analyze the degree of approximation of a function \(\overline f\) that is a conjugate of a function \(f\) belonging to the Lipschitz class by Hausdorff means of a conjugate series of the Fourier series.
    Źródło:
    Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2016, 70, 2
    0365-1029
    2083-7402
    Pojawia się w:
    Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling of influence of turbulent transition on heat transfer conditions
    Autorzy:
    Bochon, K.
    Wróblewski, W.
    Dykas, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1943251.pdf
    Data publikacji:
    2008
    Wydawca:
    Politechnika Gdańska
    Tematy:
    laminar-turbulent transition
    Conjugate Heat Transfer (CHT)
    computational fluid dynamics CFD
    Opis:
    This article deals with the turbulent transition phenomenon modelling and its influence on heat transfer. The purpose of the analyses was to verify the transition modelling implemented in the ANSYS CFX 11 commercial code for popular test cases (low flow speed) described in literature, and then use it for verification of the in-house CFD code (created for compressible flows). The inhouse CFD code has been extended lately for the Conjugate Heat Transfer modelling (CHT) as well, taking into account important flow effects, especially the turbulent transition. A Wilcox k-omega turbulence model with the Low-Reynolds modification was used in the in-house code. The calculations in ANSYS CFX were made using an SST turbulence model and a gamma-theta transition model. A fully turbulent flow was modelled by means of both codes, and the results were compared with the available experimental data. Then, the turbulent transition for several test cases was analysed with ANSYS CFX. Afterwards, the in-house CFD code was verified by means of ANSYS CFX for a higher flow speed (Mach numbers). The CHT modelling was analysed by means of both codes and the results were compared and discussed. The conducted analyses show that the results obtained by means of both codes are comparable, but the turbulence model used in the in-house CFD code is simpler and requires less computation time. A modification of two equations turbulence models can be an alternative for design problems in more developed laminar/turbulent flows.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2008, 12, 3-4; 173-184
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Bayesian virtual metrology for quality inspection of mobile repeater systems
    Autorzy:
    Kim, S. D.
    Kim, J. S.
    Mun, B. M.
    Bae, S. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/406820.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Bayesian approach
    regression
    conjugate priors
    ICS repeater
    Markov chain Monte Carlo
    Opis:
    The technology of wideband code division multiple access (WCDMA) has been applied to band selective interference cancellation system (ICS) repeaters. To inspect the telecommunication quality of the systems, quality engineers must check the shape of the signals at the corresponding frequency band of the repeaters. However, measuring the signal quality is a repetitive manual task which requires much inspection time and high costs. In the case of small-sized samples, such as the example of an ICS repeater system, Bayesian approaches have been employed to improve the estimation accuracy by incorporating prior information on the parameters of the model in consideration. This research proposes a virtual method of quality inspection for products using a correlation structure of measurement data, mainly in a Bayesian regression framework. The Bayesian regression model derives prior information from historical measurement data to predict measurements of other frequency bandwidths by exploiting the correlation structure of each measurement data. Empirical results show the potential for reducing inspection costs and time by predicting the values of adjoining frequency bandwidths through measured data of a frequency bandwidth in the course of quality inspections of ICS repeater systems.
    Źródło:
    Management and Production Engineering Review; 2016, 7, 4; 48-53
    2080-8208
    2082-1344
    Pojawia się w:
    Management and Production Engineering Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A conjugate gradient method with quasi-Newton approximation
    Autorzy:
    Koko, Jonas
    Powiązania:
    https://bibliotekanauki.pl/articles/1208176.pdf
    Data publikacji:
    2000
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    Newton and quasi-Newton methods
    unconstrained high-dimensional optimization
    conjugate gradient methods
    Opis:
    The conjugate gradient method of Liu and Storey is an efficient minimization algorithm which uses second derivatives information, without saving matrices, by finite difference approximation. It is shown that the finite difference scheme can be removed by using a quasi-Newton approximation for computing a search direction, without loss of convergence. A conjugate gradient method based on BFGS approximation is proposed and compared with existing methods of the same class.
    Źródło:
    Applicationes Mathematicae; 2000, 27, 2; 153-165
    1233-7234
    Pojawia się w:
    Applicationes Mathematicae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of high-performance techniques for solving linear systems of algebraic equations
    Autorzy:
    Grzonka, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/307729.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    Advanced Vector Extension
    conjugate gradient method
    incomplete Cholesky factorization
    preconditioning
    vector registers
    Opis:
    Solving many problems in mechanics, engineering, medicine and other (e.g., diffusion tensor magnetic resonance imaging or finite element modeling) requires the efficient solving of algebraic equations. In many cases, such systems are very complex with a large number of linear equations, which are symmetric positive-defined (SPD). This paper is focused on improving the computational efficiency of the solvers dedicated for the linear systems based on incomplete and noisy SPD matrices by using preconditioning technique – Incomplete Cholesky Factorization, and modern set of processor instructions – Advanced Vector Extension. Application of these techniques allows to fairly reduce the computational time, number of iterations of conventional algorithms and improve the speed of calculation.
    Źródło:
    Journal of Telecommunications and Information Technology; 2013, 4; 85-91
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Jacobi type conditions for singular extremals
    Autorzy:
    Dmitruk, A. V.
    Powiązania:
    https://bibliotekanauki.pl/articles/969606.pdf
    Data publikacji:
    2008
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    singular extremal
    Goh transformation
    Legendre quadratic form
    Euler-Jacobi equation
    conjugate point
    Opis:
    We consider the class of optimal control problems linear in the control, and study a singular extremal. If the Lagrange multipliers are unique, the quadratic order optimality conditions have the form of sign definiteness of a quadratic functional (the second variation of Lagrange function) with totally zero Legendre coefficient. Using the Goh transformation, we convert it to a functional possibly satisfying the strengthened Legendre condition, involving also an additional parameter, and by applying the Hestenes approach, determine its sign definiteness in terms of the conjugate point, i.e. give Jacobi type conditions.
    Źródło:
    Control and Cybernetics; 2008, 37, 2; 285-306
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal and fluid flow fields in a regenerator with ceramic chimney block checker work
    Autorzy:
    Zashkowa, L.
    Penkova, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/1965141.pdf
    Data publikacji:
    2005
    Wydawca:
    Politechnika Gdańska
    Tematy:
    glass furnace
    regenerator
    conjugate heat transfer
    cyclic equilibrium
    FEM
    thermal fields
    modelling
    Opis:
    Selected results of mathematical modelling and computer simulation of transient conjugate heat transfer in a vertical contraflow glass furnace regenerator are reported. The problem is solved three-dimensionally (3D) using the ANSYS 8.0/FLOTRAN program. The main regenerator fluid flow and thermal fields about a cyclic equilibrium of the regenerator are visualized. Heat and fluid flow parameters for the regenerator's cyclic equilibrium are presented by Tm=Tm(H',t); Tm,f=Tm,f(H',t); hm=hm(H',t); V=V(H',t); k=k(H',t) and ε=ε(H',t) graphics. Remarks about transient heat transfer in this kind of regenerators are made based on the obtained numerical values and relationships.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 143-151
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Computational and Statistical Aspects of Determining Ships Position
    Autorzy:
    Drapella, A.
    Morgaś, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/320950.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Forum Nawigacyjne
    Tematy:
    determining ship’s position
    Least Square method
    conjugate gradient
    Monte Carlo method
    Opis:
    In its mathematical essence, the task of determining ship’s position coordinates, is to minimize appropriately defined goal function. This paper proposes to use the method of conjugate gradient for this purpose. The reason is that calculations may be performed in some seconds time because Microsoft and Apache implemented the conjugate gradient method as a tool called the Solver and embedded this tool in their widely offered and popular spreadsheets, namely Excel and the Open Office Calc, respectively. Further in this paper it is shown how to precisely assess errors of ship’s position coordinates with the Monte Carlo method that employs the Solver.
    Matematyczna istota wyznaczania współrzędnych pozycji okrętu to minimalizacja odpowiednio zdefiniowanej funkcji celu. Artykuł proponuje wykorzystanie do tego metody gradientu sprzężonego. Dzięki niej obliczenia mogą być wykonane w kilka sekund, ponieważ Microsoft i Apache zaimplementowały metodę gradientu sprzężonego jako narzędzie nazwane Solver i umieściły je w swych szeroko oferowanych i popularnych arkuszach kalkulacyjnych: Excelu i Open Office Calc. W artykule pokazano także, jak precyzyjnie określić błędy oszacowania współrzędnych pozycji okrętu metodą Monte Carlo.
    Źródło:
    Annual of Navigation; 2017, 24; 5-18
    1640-8632
    Pojawia się w:
    Annual of Navigation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On an approach to the thermo-elasto-plastic failure based on the Burzynski criterion
    Autorzy:
    Banaś, K.
    Badur, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/175155.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Burzynski stress
    thermal-FSI
    conjugate heat transfer
    thermal stresses
    turbine guide vane
    Opis:
    In this paper the comparison of material eort models: the classic Huber-Mises-Hencky approach and the Burzynski condition was presented. Burzynski yield condition is pressure sensitive and naturally takes into account the strength dierential eect, which has been observed in nickel-base super alloys such as Inconel 718. Investigation was performed during thermal-uidstructure interaction analysis of a power turbine guide vane of turbine helicopter engine PZL- 10W. Firstly, computational uid dynamics conjugate heat transfer analysis was carried out, then stress analysis was performed with boundary conditions obtained via computational uid dynamics analysis. During stress analysis, two mentioned above equivalent stress denitions were applied and dierence in material eort modelling by them was shown.
    Źródło:
    Transactions of the Institute of Fluid-Flow Machinery; 2017, 136; 65-76
    0079-3205
    Pojawia się w:
    Transactions of the Institute of Fluid-Flow Machinery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowanie metody gradientów sprzężonych w algorytmie sterowania optymalnego wysokością lotu czterowirnikowego bezzałogowego statku powietrznego
    Conjugate gradient method for flight altitude optimal control algorithm of a quadrator unmanned aerial vehicle
    Autorzy:
    Brzozowski, B.
    Kowaleczko, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/213626.pdf
    Data publikacji:
    2015
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
    Tematy:
    sterowanie optymalne
    metoda gradientów sprzężonych
    quadrotor
    BSP
    optimal control
    conjugate gradient method
    UAV
    Opis:
    Artykuł przedstawia wyniki przeprowadzonych badań teoretycznych dotyczących zastosowania metody gradientów sprzężonych do rozwiązywania problemu sterowania optymalnego wysokością lotu czterowirnikowego bezzałogowego statku powietrznego (BSP). Ze względu na różnice w strategii sterowania mające wpływ na postać minimalizowanego funkcjonału jakości, problem rozdzielono na dwa zagadnienia – zmianę wysokości oraz stabilizację wysokości. Przeprowadzone analizy pozwoliły na określenie wpływu zmian postaci funkcjonału jakości, jego parametrów czasowych oraz współczynników wagowych na wyznaczoną za pomocą metody gradientów sprzężonych optymalną trajektorię stanu i sterowanie czterowirnikowego BSP podczas zmiany wysokości lotu oraz jej stabilizacji.
    This paper presents results of studies on the usage of conjugate gradient method for solving optimal control problem of flight altitude control of a quadrotor unmanned aerial vehicle (UAV). Due to the differences in the control strategy affecting the character of minimized quality functional, the problem was resolved on two issues: changing the flight altitude and altitude stabilization. Conducted researches allowed to determine the impact of changes in the form of a quality functional as well as of its timing and weighting factors on the designated optimal control and state trajectory of a quadrotor UAV using conjugate gradient method during changing and stabilizing flight altitude.
    Źródło:
    Prace Instytutu Lotnictwa; 2015, 4 (241); 7-18
    0509-6669
    2300-5408
    Pojawia się w:
    Prace Instytutu Lotnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The amide of galacturonic acid with lysine as an immunodominant component of the lipopolysaccharide core region from Proteus penneri 42 strain
    Autorzy:
    Palusiak, Agata
    Maciejewska, Anna
    Ługowski, Czesław
    Różalski, Antoni
    Powiązania:
    https://bibliotekanauki.pl/articles/1039351.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    amide of galacturonic acid with lysine
    anti-conjugate serum
    core region
    lipopolysaccharide
    Proteus
    Opis:
    Most Proteus lipopolysaccharides (LPSs) contain uronic acids or their amides with different amino acids, which together with other negatively charged components account for the acidic character of such LPS molecules. Previous studies have shown the significance of an amide of galacturonic acid with lysine [D-GalA(L-Lys)] for serological specificity of O-antigens from few P. mirabilis strains. In this work, the immunodominant role of GalALys was indicated for the P. penneri 42 LPS core region. The studies also showed the serological identity of core oligosaccharides from P. penneri 42 (O71), P. mirabilis 51/57 (O28) and R14/S1959 strains.
    Źródło:
    Acta Biochimica Polonica; 2014, 61, 1; 129-132
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Minima in control problems with constraints
    Autorzy:
    Stefani, Gianna
    Zezza, PierLuigi
    Powiązania:
    https://bibliotekanauki.pl/articles/1359682.pdf
    Data publikacji:
    1995
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    state-control constraint
    necessary
    second order conditions
    conjugate points
    optimal control
    sufficient conditions
    Opis:
    This paper is devoted to describing second order conditions in the framework of extremal problems, that is, conditions obtained by reducing the optimal control problem to an abstract one in a suitable Banach (or Hilbert) space. The studied problem includes equality constraints both on the end-points and on the state-control trajectory. The second goal is to give a complete description of necessary and sufficient second order conditions for weak local optimality by describing first the associated linear-quadratic problem and then by giving a conjugate point theory for this linear quadratic problem with constraints.
    Źródło:
    Banach Center Publications; 1995, 32, 1; 361-378
    0137-6934
    Pojawia się w:
    Banach Center Publications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Can conjugate prior probability explain the illusion of control?
    Autorzy:
    Czupryna, Marcin
    Kubińska, Elżbieta
    Markiewicz, Łukasz
    Powiązania:
    https://bibliotekanauki.pl/articles/1198684.pdf
    Data publikacji:
    2018
    Wydawca:
    Akademia Leona Koźmińskiego w Warszawie
    Tematy:
    overconfidence
    illusion of control
    emotional and rational model
    Bayesian updating
    conjugate prior probability.
    Opis:
    In this paper, we consider the illusion of control by using Bayesian updating as the rationality model. Our paper contributes twofold. First, we empirically verify that the illusion of control may have two concurrent sources, “emotional” and “rational”. The fi rst one produces biased Bayesian processing due to emotional engagement and the second one yields biases due to prior assumptions on the level of control. Second, we propose a method for identifying these two sources. Moreover we verified two hypotheses H1: The emotional factor causes overestimation of the actual level of control. and H2: The rational factor is responsible for the reverse relationship between observed levels of the illusion of control in three separate situations, when subjects have significant control, moderate or no control. Only the hypothesis H2 received partial empirical support.
    Źródło:
    Decyzje; 2018, 29; 87-113
    1733-0092
    2391-761X
    Pojawia się w:
    Decyzje
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The aircraft piston engine conjugate heat transfer model
    Autorzy:
    Tulwin, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/246920.pdf
    Data publikacji:
    2017
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    CFD
    fluid
    dynamics
    conjugate
    coupled
    heat
    transfer
    engine
    SI
    płyn
    dynamika
    ciepło
    silnik
    Opis:
    Maintaining high aircraft’s propulsion system reliability requires a good knowledge of engine’s heat transfer conditions at each engine running time. Even though the flow around the cylinder may be steady, the heat flux from the engine is not evenly distributed. This is caused by varied engine head and fins geometry and uneven heat transfer coefficient distribution. The lack of knowledge of the local heat transfer coefficient values and time coefficients for the transient heat transfer make it unfeasible to make an analytical model for a given geometry. One transient Computational Fluid Dynamics simulation does not solve the heat transfer fully. Only a conjugate simulation allows an in-depth analysis of a transient heat transfer. The Combustion and species transport fluid simulation is coupled to the temperature field solid simulation. This work presents the methods and results of such conjugate heat transfer simulation. The change of heat flux parameters in respect to time is shown. The results are verified by the real engine measurements.
    Źródło:
    Journal of KONES; 2017, 24, 1; 349-355
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A parallel algorithm of icsym forcomplexsymmetric linear systems in quantum chemistry
    Autorzy:
    Zhang, Y.
    Lv, Q.
    Xiao, M.
    Xie, G.
    Breitkopf, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/305677.pdf
    Data publikacji:
    2018
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    complex symmetric linear systems
    parallel computing
    improved conjugate gradient-type iterative algorithm (ICSYM)
    Opis:
    Computational effort is a common issue for solving large-scale complex symmetric linear systems, particularly in quantum chemistry applications. In order to alleviate this problem, we propose a parallel algorithm of improved conjugate gradient-type iterative (ICSYM). Using three-term recurrence relation and or- thogonal properties of residual vectors to replace the tridiagonalization process of classical CSYM, which allows to decrease the degree of the reduce-operator from two to one communication at each iteration and to reduce the amount of vector updates and vector multiplications. Several numerical examples are implemented to show that high performance of proposed improved version is obtained both in convergent rate and in parallel efficiency.
    Źródło:
    Computer Science; 2018, 19 (4); 385-401
    1508-2806
    2300-7036
    Pojawia się w:
    Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On an Improvement of the Model-Based Clustering Method
    O pewnej modyfikacji w metodzie taksonomii opartej na modelach mieszanych
    Autorzy:
    Witek, Ewa
    Powiązania:
    https://bibliotekanauki.pl/articles/906293.pdf
    Data publikacji:
    2009
    Wydawca:
    Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
    Tematy:
    Model-based clustering (MBC)
    Gaussian mixture models
    EM algorithm
    MLE
    MAP
    BIC
    conjugate prior
    Opis:
    W artykule przedstawiona została modyfikacja metody taksonomii opartej na modelach mieszanych, w przypadku gdy niemożliwym staje się oszacowanie parametrów modelu za pomocą algorytmu EM. Gdy liczba obiektów przypisanych do klasy jest mniejsza niż liczba zmiennych opisujących te obiekty, niemożliwym staje się oszacowanie parametrów modelu. By uniknąć tej sytuacji estymatory największej wiarygodności zastępowane są estymatorami o największym prawdopodobieństwie a posteriori. Wybór modelu o najlepszej parametryzacji i stosownej liczbie klas dokonywany jest wówczas za pomocą zmodyfikowanej statystyki BIC.
    An improvement o f the model-based clustering (MBC) method in the case when EM algorithm fails as a result o f singularities is the basic aim o f this paper. Replacement o f the maximum likelihood (MLE) estimator by a maximum a posteriori (MAP) estimator, also found by the EM algorithm is proposed. Models with different number o f components are compared using a modified version o f BIC, where the likelihood is evaluated at the MAP instead o f MLE. A highly dispersed proper conjugate prior is shown to avoid singularities, but when these are not present it gives similar results to the standard method o f MBC.
    Źródło:
    Acta Universitatis Lodziensis. Folia Oeconomica; 2009, 228
    0208-6018
    2353-7663
    Pojawia się w:
    Acta Universitatis Lodziensis. Folia Oeconomica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Operator-splitting and Lagrange multiplier domain decomposition methods for numerical simulation of two coupled Navier-Stokes fluids
    Autorzy:
    Bresch, D.
    Koko, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/908383.pdf
    Data publikacji:
    2006
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    dwoistość
    gradient sprzężony
    przepływ Naviera-Stokesa
    domain decomposition
    duality
    conjugate gradient
    Navier-Stokes flows
    Opis:
    We present a numerical simulation of two coupled Navier-Stokes flows, using operator-splitting and optimization-based nonoverlapping domain decomposition methods. The model problem consists of two Navier-Stokes fluids coupled, through a common interface, by a nonlinear transmission condition. Numerical experiments are carried out with two coupled fluids; one with an initial linear profile and the other in rest. As expected, the transmission condition generates a recirculation within the fluid in rest.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2006, 16, 4; 419-429
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Training neural networks with a hybrid differential evolution algorithm
    Uczenie sieci neuronowych hybrydowym algorytmem opartym na differential evolution
    Autorzy:
    Bandurski, K.
    Kwedlo, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/341051.pdf
    Data publikacji:
    2009
    Wydawca:
    Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
    Tematy:
    sieci neuronowe
    differential evolution
    gradienty sprzężone
    minima lokalne
    neural networks
    conjugate gradients
    local minima
    Opis:
    A new hybrid method for feed forward neural network training, which combines differential evolution algorithm with a gradient-based approach is proposed. In the method, after each generation of differential evolution, a number of iterations of the conjugate gradient optimization algorithm is applied to each new solution created by the mutation and crossover operators. The experimental results show, that in comparison to the standard differential evolution the hybrid algorithm converges faster. Although this convergence is slower than that of classical gradient based methods, the hybrid algorithm has significantly better capability of avoiding local optima.
    W artykule przedstawiono nową, hybrydową metodę uczenia sieci neuronowych, łączącą w sobie algorytm Differential Evolution z podejściem gradientowym. W nowej metodzie po każdej generacji algorytmu Differential Evolution, każde nowe rozwiązanie, powstałe w wyniu działania operatorów krzyżowania i mutacji, poddawane jest kilku iteracjom algorytmu optymalizacji wykorzystującego metodę gradientów sprzężonych.Wyniki eksperymentów wskazują, że nowy, hybrydowy algorytm ma szybszą zbieżność niż standardowy algorytm Differential Evolution. Mimo, iż zbieżność ta jest wolniejsza, niż w przypadku klasycznych metod gradientowych, algorytm hybrydowy potrafi znacznie lepiej unikać minimów lokalnych.
    Źródło:
    Zeszyty Naukowe Politechniki Białostockiej. Informatyka; 2009, 4; 5-17
    1644-0331
    Pojawia się w:
    Zeszyty Naukowe Politechniki Białostockiej. Informatyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nd-solid varieties
    Autorzy:
    Denecke, Klaus
    Glubudom, Prisana
    Powiązania:
    https://bibliotekanauki.pl/articles/728884.pdf
    Data publikacji:
    2007
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    Non-deterministic hypersubstitution
    conjugate pair of additive closure operators
    M-solid non-deterministic variety
    Opis:
    A non-deterministic hypersubstitution maps any operation symbol of a tree language of type τ to a set of trees of the same type, i.e. to a tree language. Non-deterministic hypersubstitutions can be extended to mappings which map tree languages to tree languages preserving the arities. We define the application of a non-deterministic hypersubstitution to an algebra of type τ and obtain a class of derived algebras. Non-deterministic hypersubstitutions can also be applied to equations of type τ. Formally, we obtain two closure operators which turn out to form a conjugate pair of completely additive closure operators. This allows us to use the theory of conjugate pairs of additive closure operators for a characterization of M-solid non-deterministic varieties of algebras. As an application we consider M-solid non-deterministic varieties of semigroups.
    Źródło:
    Discussiones Mathematicae - General Algebra and Applications; 2007, 27, 2; 245-262
    1509-9415
    Pojawia się w:
    Discussiones Mathematicae - General Algebra and Applications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Functional reconstitution of Ral-binding GTPase activating protein, RLIP76, in proteoliposomes catalyzing ATP-dependent transport of glutathione conjugate of 4-hydroxynonenal.
    Autorzy:
    Sharma, Rajendra
    Sharma, Abha
    Yang, Yusong
    Awasthi, Sanjay
    Singhal, Sharad
    Zimniak, Piotr
    Awasthi, Yogesh
    Powiązania:
    https://bibliotekanauki.pl/articles/1043735.pdf
    Data publikacji:
    2002
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    RLIP76
    4-hydroxynonenal
    Ral-binding GTPase activating protein
    transport
    glutathione conjugate of 4-hydroxynonenal
    Opis:
    Earlier studies from our laboratories have shown that RLIP76, a previously described Ral-binding GTPase activating protein (Jullien-Flores et al., 1995, J. Biol. Chem. 270: 22473), is identical with the xenobiotic transporter DNP-SG ATPase, and can catalyze ATP-dependent transport of glutathione-conjugates as well as doxorubin (Awasthi et al., 2000, Biochemistry, 39: 9327). We have now reconstituted purified bacterially expressed RLIP76 in proteoliposomes, and have studied ATP-dependent uptake of the glutathione conjugate of 4-hydroxynonenal (GS-HNE) by these vesicles. Results of these studies show that RLIP76 reconstituted in proteoliposomes catalyzes ATP-dependent transport of GS-HNE against a concentration gradient. The transport of GS-HNE is saturable with respect to ATP as well as GS-HNE with Km values of 1.4 mM and 2.5 μM, respectively. These studies demonstrate that RLIP76 mediates active transport of GS-HNE, and are consistent with our previous work showing that RLIP76-mediated efflux of GS-HNE regulates the intracellular concentration of 4-HNE and thereby affects 4-HNE mediated signaling.
    Źródło:
    Acta Biochimica Polonica; 2002, 49, 3; 693-701
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Newtons iteration with a conjugate gradient based decomposition method for an elliptic PDE with a nonlinear boundary condition
    Autorzy:
    Koko, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/907312.pdf
    Data publikacji:
    2004
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    metoda Newtona
    metoda gradientu sprzężonego
    warunek brzegowy nieliniowy
    Newton's method
    conjugate gradient method
    nonlinear PDE
    Opis:
    Newton's iteration is studied for the numerical solution of an elliptic PDE with nonlinear boundary conditions. At each iteration of Newton's method, a conjugate gradient based decomposition method is applied to the matrix of the linearized system. The decomposition is such that all the remaining linear systems have the same constant matrix. Numerical results confirm the savings with respect to the computational cost, compared with the classical Newton method with factorization at each step.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2004, 14, 1; 13-18
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Choice of Subspace for Iterative Methods for Linear Discrete Ill-Posed Problems
    Autorzy:
    Calvetti, D.
    Lewis, B.
    Reichel, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/908057.pdf
    Data publikacji:
    2001
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    metoda sprzężonych gradientów
    problem niewłaściwie postawiony
    minimal residual method
    conjugate gradient method
    ill-posed problems
    Opis:
    Many iterative methods for the solution of linear discrete ill-posed problems with a large matrix require the computed approximate solutions to be orthogonal to the null space of the matrix. We show that when the desired solution is not smooth, it may be possible to determine meaningful approximate solutions with less computational work by not imposing this orthogonality condition.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2001, 11, 5; 1069-1092
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    M-solid generalized non-deterministic varieties
    Autorzy:
    Lekkoksung, Somsak
    Powiązania:
    https://bibliotekanauki.pl/articles/728876.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    generalized non-deterministic hypersubstitution
    conjugate pair of additive closure operators
    M-solid generalized non-deterministic variety
    Opis:
    A generalized non-deterministic hypersubstitution is a mapping which maps operation symbols of type τ to the set of terms of the same type which does not necessarily preserve the arity. We apply the generalized non-deterministic hypersubstitution to an algebra of type τ and obtain a class of derived algebras of type τ. The generalized non-deterministic hypersubstitutions can be also applied to sets of equations of type τ. We obtain two closure operators which turn out to be a conjugate pair of completely additive closure operators. This allows us to apply the theory of conjugate pairs of additive closure operators to characterize M-solid generalized non-deterministic varieties of algebras.
    Źródło:
    Discussiones Mathematicae - General Algebra and Applications; 2016, 36, 1; 25-43
    1509-9415
    Pojawia się w:
    Discussiones Mathematicae - General Algebra and Applications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Systemy wieloprocesorowe w automatyce i pomiarach
    Multiprocesor systems in automatic control and measurements
    Autorzy:
    Jordan, A.
    Bycul, R.
    Forenc, J.
    Myszkowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/158209.pdf
    Data publikacji:
    2004
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    klaster
    przetwarzanie równoległe
    metoda gradientu sprzężonego
    metoda spekulacyjna
    cluster
    parallel processing
    conjugate gradient method
    speculative method
    Opis:
    Artykuł przedstawia konstrukcję homogenicznego systemu klaster - KETIM2, oraz dwa przykłady jego wykorzystania do rozwiązywania wybranych zagadnień z teorii sterowania i przybliżonych metod elektrotechniki. Pierwszym z nich jest równoległa implementacja algorytmu gradientu sprzężonego wykorzystywanego w teorii optymalizacji i metodzie elementów skończonych. Drugi przykład dotyczy równoległej analizy stanów nieustalonych w układach opisanych nieliniowym równaniem stanu. W tym drugim przypadku analizowano dynamikę silnika asynchronicznego pierścieniowego stosując metodę spekulacyjną. Przedstawiono również perspektywy zastosowań systemów wieloprocesorowych w technice pomiarowej.
    The paper presents the construction of a homogenous cluster system - KETIM2 and two examples of its application for solving selected problems of control theory and approximate methods of electrical engineering. First of them is a parallel implementation of the conjugate gradient algorithm applied in the optimization theory and in the method of finite elements. The second example concerns parallel analysis of transient states in a dynamic system described by a nonlinear state equation. In the second case dynamics of asynchronous slip-ring motor was analysed appluing a speculative method. The perspectives of applications of multiprocessor systems in measurement technique were also presented.
    Źródło:
    Pomiary Automatyka Kontrola; 2004, R. 50, nr 10, 10; 16-20
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of turbulence model, turbulence length scale and wall roughness on the laminar-turbulence transition and temperature distribution of a convectively cooled C3X turbine vane
    Autorzy:
    Banaś, K.
    Badur, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/175460.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    laminar-turbulent transition
    conjugate heat transfer analysis of turbine
    C3X turbine vane
    roughness correction
    Opis:
    Our paper demonstrates the ability of Favre-averaged Navier–Stokes (FANS) turbulence models to predict the laminar-turbulent transition and shows the influence of the models on the wall temperature distribution. The investigations were based on conjugate heat transfer analyses of a convectively cooled C3X turbine vane, which were performed using commercial flow simulation software. We compared several eddy-viscosity models: shear stress transport (SST), γ-Reθ SSTtransition, v2-f, k-ε, realizable, k-kl-ω transition, and second-order closure ε-based Reynolds stress model (RSM) with a linear pressure-strain model. The turbulence length scale (TLS) was not measured during the experiment, so its influence on the location of the transition onset and wall temperature distribution is presented. We also examined the influence of the roughness of the airfoil wall on the location of turbulence initialization and the wall temperature distribution.
    Źródło:
    Transactions of the Institute of Fluid-Flow Machinery; 2017, 138; 13-32
    0079-3205
    Pojawia się w:
    Transactions of the Institute of Fluid-Flow Machinery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conjugate functions, lp-norm like functionals, the generalized Hölder inequality, Minkowski inequality and subhomogeneity
    Autorzy:
    Matkowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/255030.pdf
    Data publikacji:
    2014
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    Lp-norm like functional
    homogeneity
    subhomogeneity
    subadditivity
    Minkowski inequality
    Hölder inequality
    converses
    generalization of the Minkowski and Hölder inequalities
    conjugate functions
    complementary functions
    Young conjugate functions
    convex function
    geometrically convex function
    Wright convex function
    functional equation
    Opis:
    For h : (0,∞) → R, the function h* (t) := th( 1/t ) is called (*)-conjugate to h. This conjugacy is related to the Hölder and Minkowski inequalities. Several properties of (*)-conjugacy are proved. If φ and φ* are bijections of (0,∞) then [formula]. Under some natural rate of growth conditions at 0 and ∞, if φ is increasing, convex, geometrically convex, then [formula] has the same properties. We show that the Young conjugate functions do not have this property. For a measure space (Ω,Σ,μ) denote by S = (Ω,Σ,μ) the space of all μ-integrable simple functions x : Ω → R, Given a bijection φ : (0,∞) → (0,∞) define [formula] by [formula] where Ω(x) is the support of x. Applying some properties of the (*) operation, we prove that if ƒ xy ≤ Pφ(x)Pψ (y) where [formula] and [formula] are conjugate, then φ and ψ are conjugate power functions. The existence of nonpower bijections φ and ψ with conjugate inverse functions [formula] such that Pφ and Pψ are subadditive and subhomogeneous is considered.
    Źródło:
    Opuscula Mathematica; 2014, 34, 3; 523-560
    1232-9274
    2300-6919
    Pojawia się w:
    Opuscula Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparative study of conjugate gradient algorithms performance on the example of steady-state axisymmetric heat transfer problem
    Autorzy:
    Ocłoń, P.
    Łopata, S.
    Nowak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/240612.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conjugate gradient method
    finite element method
    finned circular tube
    metoda gradientu sprzężonego
    metoda elementów skończonych
    rury żebrowane
    Opis:
    The finite element method (FEM) is one of the most frequently used numerical methods for finding the approximate discrete point solution of partial differential equations (PDE). In this method, linear or nonlinear systems of equations, comprised after numerical discretization, are solved to obtain the numerical solution of PDE. The conjugate gradient algorithms are efficient iterative solvers for the large sparse linear systems. In this paper the performance of different conjugate gradient algorithms: conjugate gradient algorithm (CG), biconjugate gradient algorithm (BICG), biconjugate gradient stabilized algorithm (BICGSTAB), conjugate gradient squared algorithm (CGS) and biconjugate gradient stabilized algorithm with l GMRES restarts (BICGSTAB(l)) is compared when solving the steady-state axisymmetric heat conduction problem. Different values of l parameter are studied. The engineering problem for which this comparison is made is the two-dimensional, axisymmetric heat conduction in a finned circular tube.
    Źródło:
    Archives of Thermodynamics; 2013, 34, 3; 15-44
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Horizontal lift of symmetric connections to the bundle of volume forms \(\mathcal{V}\)
    Autorzy:
    Gasior, Anna
    Powiązania:
    https://bibliotekanauki.pl/articles/747213.pdf
    Data publikacji:
    2010
    Wydawca:
    Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
    Tematy:
    Horizontal lift
    \(\pi\)-conjugate connection
    Killing field
    infinitesimal transformation
    \(F(3, 1)\)-structure
    FK, FAK, FNK, FQK, FH-structure
    Opis:
    In this paper we present the horizontal lift of a symmetric affine connection with respect to another affine connection to the bundle of volume forms \(\mathcal{V}\) and give formulas for its curvature tensor, Ricci tensor and the scalar curvature. Next, we give some properties of the horizontally lifted vector fields and certain infinitesimal transformations. At the end, we consider some substructures of a \(F(3, 1)\)-structure on \(\mathcal{V}\).
    Źródło:
    Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2010, 54, 1
    0365-1029
    2083-7402
    Pojawia się w:
    Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The converse of the Hölder inequality and its generalizations
    Autorzy:
    Matkowski, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1290537.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    measure space
    integrable step functions
    conjugate functions
    a converse of Hölder inequality
    subadditive function
    convex function
    generalized Hölder-Minkowski inequality
    Opis:
    Let (Ω,Σ,μ) be a measure space with two sets A,B ∈ Σ such that 0 < μ (A) < 1 < μ (B) < ∞ and suppose that ϕ and ψ are arbitrary bijections of [0,∞) such that ϕ(0) = ψ(0) = 0. The main result says that if $ʃ_Ω xydμ ≤ ϕ^{-1} (\int_{Ω} ϕ∘x dμ) ψ^{-1} (\int_{Ω} ψ∘x dμ)$ for all μ-integrable nonnegative step functions x,y then ϕ and ψ must be conjugate power functions. If the measure space (Ω,Σ,μ) has one of the following properties: (a) μ (A) ≤ 1 for every A ∈ Σ of finite measure; (b) μ (A) ≥ 1 for every A ∈ Σ of positive measure, then there exist some broad classes of nonpower bijections ϕ and ψ such that the above inequality holds true. A general inequality which contains integral Hölder and Minkowski inequalities as very special cases is also given.
    Źródło:
    Studia Mathematica; 1994, 109, 2; 171-182
    0039-3223
    Pojawia się w:
    Studia Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Typy szczepionek i skuteczność szczepień ochronnych wykorzystywanych w profilaktyce zakażeń Streptococcus pneumoniae
    Types of vaccines and effectiveness of immunization used in the prevention of Streptococcus pneumoniae infections
    Autorzy:
    Nogawka, A.
    Jatulewicz, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/410357.pdf
    Data publikacji:
    2012
    Wydawca:
    Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
    Tematy:
    pneumokoki
    polisacharydowa szczepionka pneumokokowa
    skoniugowana szczepionka pneumokokowa
    zakażenia Streptococcus pneumonia
    profilaktyka
    Pneumococci
    Pneumococcal Polisaccharide Vaccine
    Pneumococcal Conjugate Vaccine
    Streptococcus pneumoniae infections
    prophylaxis
    Opis:
    Zakażenia pneumokokowe stanowią istotny problem zdrowotny, zwłaszcza u małych dzieci, pacjentów z grupy ryzyka i osób starszych. W artykule omówiono profilaktykę choroby pneumokokowej za pomocą szczepionek: polisacharydowej i skoniugowanej. Praca zawiera również informacje odnośnie ich skuteczności w różnych grupach wiekowych i ryzyka, a także aktualne wskazania do stosowania tych szczepionek.
    Pneumococcal infections pose an important health problem, especially to young children, patients at high risk and elderly people. In the article we discuss a prophylaxis of pneumococcal disease with polysaccharide vaccines and conjugated vaccines. This report contains information on their effectiveness in various age and risk groups, and current recommendations for vaccination.
    Źródło:
    Chemistry, Environment, Biotechnology; 2012, 15; 19-26
    2083-7097
    Pojawia się w:
    Chemistry, Environment, Biotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Protective action of vitamin C against DNA damage induced by selenium-cisplatin conjugate.
    Autorzy:
    Błasiak, Janusz
    Kowalik, Joanna
    Powiązania:
    https://bibliotekanauki.pl/articles/1044192.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    endonuclease III
    vitamin C
    Se-Pt conjugate [(NH3)2Pt(SeO3)]
    genotoxic effects of anticancer drugs
    DNA damage
    comet assay
    DNA repair
    Opis:
    Genotoxicity of anticancer drugs is of a special interest due to the risk of inducing secondary malignancies. Vitamin C (ascorbic acid) is a recognized antioxidant and, since human diet can be easily supplemented with vitamin C, it seems reasonable to check whether it can protect against DNA-damaging effects of antitumor drugs. In the present work the ability of vitamin C to modulate cytotoxic and genotoxic effects of a cisplatin analog, conjugate (NH3)2Pt(SeO3), in terms of cell viability, DNA damage and repair in human lymphocytes was examined using the trypan blue exclusion test and the alkaline comet assay, respectively. The conjugate evoked a concentration-dependent decrease in the cell viability, reaching nearly 50% at 250 μM. (NH3)2Pt(SeO3) at 1, 10 and 30 μM caused DNA strand breaks, measured as the increase in the comet tail moment of the lymphocytes. The treated cells were able to recover within a 30-min incubation in a drug-free medium at 37°C. Vitamin C at 10 and 50 μM diminished the extent of DNA damage evoked by (NH3)2Pt(SeO3) but had no effect on the kinetics of DNA repair. The vitamin did not directly inactivate the conjugate. Lymphocytes treated with endonuclease III, which recognises oxidised pyrimidines, displayed a greater tail moment than those untreated with the enzyme, suggesting that the damages induced by the drug have, at least in part, an oxidative origin. Vitamin C can be considered a potential protective agent against side effects of antitumor drugs, but further research with both normal and cancer cells are needed to clarify this point.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 1; 233-240
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Symmetrized semi-smooth Newton method for solving 3D contact problems
    Symetrizovaná nehladká Newtonova metoda pro rešení 3D kontaktních úloh
    Autorzy:
    Kucera, R.
    Haslinger, J.
    Motycková, K.
    Markopoulos, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/112650.pdf
    Data publikacji:
    2017
    Wydawca:
    STE GROUP
    Tematy:
    contact problem
    Tresca friction
    semi-smooth Newton methods
    conjugate gradient method
    gradient projection
    convergence rate
    zagadnienie kontaktowe
    tarcie Treski
    metoda gradientu sprzężonego
    rzutowanie gradientu
    szybkość konwergencji
    Opis:
    The semi-smooth Newton method for solving discretized contact problems with Tresca friction in three space dimensions is analyzed. The slanting function is approximated to get symmetric inner linear systems. The primal-dual algorithm is transformed into the dual one so that the conjugate gradient method can be used. The R-linear convergence rate is proved for an inexact globally convergent variant of the method. Numerical experiments conclude the paper. The contact problems are important in many practical applications, e.g., biological processes, design of machines, transportation systems, metal forming, or medicine (bone replacements).
    V práci je analyzována nehladká Newtonova metoda pro rešení diskretizovaných kontaktních úloh s Trescovým trením ve trech prostorových dimenzích. Slanting funkce je aproximována za úcelem získání symetrických vnitrních lineárních úloh. Pro použití metody sdružených gradientu je primárne-duální algoritmus preveden na duální. R-lineární rychlost konvergence je dokázána pro nepresnou globálne konvergentní variantu metody. Záverem jsou uvedeny numerické experimenty. Kontaktní úlohy mají radu významných aplikací, napr. biologické procesy, design stroju a prepravních systému, tvárení kovu nebo medicína (modelování kostních náhrad).
    Źródło:
    Systemy Wspomagania w Inżynierii Produkcji; 2017, 6, 4; 286-293
    2391-9361
    Pojawia się w:
    Systemy Wspomagania w Inżynierii Produkcji
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synteza biodegradowalnych poliestrów z zastosowaniem katalizatorów i inicjatorów naturalnych
    Synthesis of biodegradable polyesters using natural catalysts and initiators
    Autorzy:
    Sawicka, A.
    Oledzka, E.
    Sobczak, M.
    Kołodziejski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/947524.pdf
    Data publikacji:
    2017
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
    Tematy:
    polimer biodegradowalny
    koniugat wielkocząsteczkowy
    prolek wielkocząsteczkowy
    polimeryzacja z otwarciem pierścienia (ROP)
    katalizator
    naturalny inicjator
    biodegradable polymer
    macromolecular conjugate
    macromolecular prodrug
    ring-opening polymerization (ROP)
    catalyst
    natural initiator
    Opis:
    Artykuł stanowi przegląd literatury dotyczącej wykorzystania związków pochodzenia naturalnego i nietoksycznych jako inicjatorów i/lub katalizatorów polimeryzacji z otwarciem pierścienia (ROP) cyklicznych estrów prowadzącej do otrzymania biodegradowalnych i bioresorbowalnych poliestrów stosowanych w medycynie i farmacji. Dokonano klasyfikacji naturalnych inicjatorów ROP na zawierające funkcyjne grupy aminowe lub hydroksylowe. Opisano również możliwość zastosowania związków naturalnych jako kokatalizatorów ROP oraz naturalnych katalizatorów organicznych tego procesu.
    The paper is a review of the literature concerning the application of non-toxic and natural compounds, as initiators and/or catalysts of ring-opening polymerization (ROP) of cyclic esters in the synthesis of biodegradable and bioresorbable polymers for medical and pharmaceutical purposes. The classification of natural ROP initiators as those containing functional amino and hydroxyl groups has been presented. The possibility of using natural compounds as ROP cocatalysts and organocatalysts was also described.
    Źródło:
    Polimery; 2017, 62, 9; 633-641
    0032-2725
    Pojawia się w:
    Polimery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Quartic non-polynomial spline solution for solving two-point boundary value problems by using Conjugate Gradient iterative method
    Autorzy:
    Justine, H.
    Chew, J. V. L.
    Sulaiman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/122546.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    two-point boundary value problems
    quartic non-polynomial spline
    Conjugate Gradient
    Successive Over-Relaxation
    Gauss-Seidel
    dwupunktowe problemy brzegowe
    metoda gradientu sprzężonego
    metoda Gaussa-Seidela
    metoda iteracyjna
    Opis:
    Solving two-point boundary value problems has become a scope of interest among many researchers due to its significant contributions in the field of science, engineering, and economics which is evidently apparent in many previous literary publications. This present paper aims to discretize the two-point boundary value problems by using a quartic non-polynomial spline before finally solving them iteratively with Conjugate Gradient (CG) method. Then, the performances of the proposed approach in terms of iteration number, execution time and maximum absolute error are compared with Gauss-Seidel (GS) and Successive Over-Relaxation (SOR) iterative methods. Based on the performances analysis, the two-point boundary value problems are found to have the most favorable results when solved using CG compared to GS and SOR methods.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2017, 16, 1; 41-50
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Two implementations of the preconditioned conjugate gradient method on heterogeneous computing grids
    Autorzy:
    Collignon, T. P.
    Van Gijzen, M. B.
    Powiązania:
    https://bibliotekanauki.pl/articles/907778.pdf
    Data publikacji:
    2010
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    przetwarzanie siatkowe
    system liniowy
    metoda iteracyjna
    gradient sprzężony
    przepływ pęcherzykowy
    grid computing
    large sparse linear systems
    iterative methods
    conjugate gradient method
    Chronopoulos/Gear CG
    GridSolve middleware
    bubbly flows
    Opis:
    Efficient iterative solution of large linear systems on grid computers is a complex problem. The induced heterogeneity and volatile nature of the aggregated computational resources present numerous algorithmic challenges. This paper describes a case study regarding iterative solution of large sparse linear systems on grid computers within the software constraints of the grid middleware GridSolve and within the algorithmic constraints of preconditioned Conjugate Gradient (CG) type methods. We identify the various bottlenecks induced by the middleware and the iterative algorithm. We consider the standard CG algorithm of Hestenes and Stiefel, and as an alternative the Chronopoulos/Gear variant, a formulation that is potentially better suited for grid computing since it requires only one synchronisation point per iteration, instead of two for standard CG. In addition, we improve the computation-to-communication ratio by maximising the work in the preconditioner. In addition to these algorithmic improvements, we also try to minimise the communication overhead within the communication model currently used by the GridSolve middleware. We present numerical experiments on 3D bubbly flow problems using heterogeneous computing hardware that show lower computing times and better speed-up for the Chronopoulos/Gear variant of conjugate gradients. Finally, we suggest extensions to both the iterative algorithm and the middleware for improving granularity.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2010, 20, 1; 109-121
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of Conjugate Heat Transfer in Electromagnetic Liquid Metal Dream Pipe
    Autorzy:
    Puvaneswari, P.
    Shailendhra, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/140031.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    enhancement of heat transfer
    dream pipe
    conjugate heat transfer
    laminar flow
    oscillatory flow
    hydromagnetic flow
    liquid metals
    zwiększenie przepływu ciepła
    rura typu dream-pipe
    sprzężona wymiana ciepła
    przepływ laminarny
    przepływ oscylacyjny
    przepływ hydromagnetyczny
    metale ciekłe
    Opis:
    The combined effect of conjugation, external magnetic field and oscillation on the enhancement of heat transfer in the laminar flow of liquid metals between parallel plate channels is analyzed. In order to make our results useful to the design engineers, we have considered here only the wall materials that are widely employed in liquid metal heat exchangers. Indeed, all the results obtained through this mathematical investigation are in excellent agreement with the available experimental results. The effective thermal diffusivity κe is increased by 3 · 106 times due to oscillation and that the heat flux as high as 1.5 · 1010 (W/m2) can be achieved. Based on our investigation, we have recommended the best choice of liquid metal heat carrier, wall material and its optimum thickness along with the optimum value of the frequency to maximize the heat transfer rate. At the optimum frequency, by choosing a wall of high thermal conductivity and optimum thickness, an increase of 19.98% in κe can be achieved. Our results are directly relevant to the design of a heat transfer device known as electromagnetic dream pipe which is a very recent development.
    Źródło:
    Archive of Mechanical Engineering; 2017, LXIV, 3; 375-399
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Weakly m-convex sets and the shadow problem
    Zbiory słabo m-wypukłe i problem cienia
    Autorzy:
    Klishchuk, Bogdan A.
    Powiązania:
    https://bibliotekanauki.pl/articles/699892.pdf
    Data publikacji:
    2018
    Wydawca:
    Łódzkie Towarzystwo Naukowe
    Tematy:
    m-convex set, weakly m-convex set, Grassmann manifold, conjugate set, shadow problem, 1-hull of family of sets
    zbiór m-wypukły, zbiór słabo m-wypukły, rozmaitość Grassmanna, zbiór sprzężony, problem cienia, 1-otoczka rodziny zbiorów
    Opis:
    https://doi.org/10.26485/0459-6854/2018/68.2/5 Badamy własności zbiorów s labo m-wypukłych w n-wymiarowej przestrzeni euklidesowej. Uzyskujemy oszacowania dla rożnych wariantów problemu cienia w ustalonym punkcie. Analizujemy również kilka nierozwiązanych zagadnień.
    https://doi.org/10.26485/0459-6854/2018/68.2/5 In this paper we study some properties of weakly m-convex sets in n-dimensional Euclidean space. We obtain estimates for different variants of the shadow problem at a fixed point. We discuss unsolved questions related to this problem.
    Źródło:
    Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations; 2018, 68, 2; 53-60
    1895-7838
    2450-9329
    Pojawia się w:
    Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Generalization of the concept of convexity in a hypercomplex space
    Uogólnienie idei wypukłości na przestrzenie hiperzespolone
    Autorzy:
    Stefanchuk, Mariia V.
    Powiązania:
    https://bibliotekanauki.pl/articles/699808.pdf
    Data publikacji:
    2018
    Wydawca:
    Łódzkie Towarzystwo Naukowe
    Tematy:
    hypercomplexly convex set, h-hull of a set, h-extremal point, hextremal ray, H-quasiconvex set, linearly convex function, conjugate function
    zbiór hiperzespolenie wypukły, h-otoczka zbioru, punkt h-ekstremalny, zbiór H-guasi-wypukły, funkcja liniowo wypukła, funkcja sprzężona
    Opis:
    https://doi.org/10.26485/0459-6854/2018/68.2/9 Badamy ekstremalne elementy i h-otoczki zbiorów z n-wymiarowej przestrzeni hiperzespolonej Hn. Wprowadzana jest klasa zbiorów H-quasi-wypukłych włączając zbiory silnie hiperzespolenie wypukłe, domknięte w odniesieniu do przecięć. Pewne wyniki dotyczące funkcji wielowartościowych w przestrzeniach zespolonych są uogólnione na przestrzenie hiperzespolone. Dotyczy to twierdzenia Fenchela-Moreau i pewnych własności funkcji sprzężonych do funkcji f : Hn  \ Ɵ à H.
    https://doi.org/10.26485/0459-6854/2018/68.2/9 Extremal elements and a h-hull of sets in the n-dimensional hypercomplex space Hn are investigated. The class of H-quasiconvex sets including strongly hypercomplexly convex sets and closed relatively to intersections is introduced. Some results concerning multivalued functions in the complex space were generalized into the n-dimensional hypercomplex space: there was proved the hypercomplex analogue of the Fenchel-Moreau theorem and some properties of functions that are conjugate to functions f : Hn  \ Ɵ à H.
    Źródło:
    Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations; 2018, 68, 2; 85-94
    1895-7838
    2450-9329
    Pojawia się w:
    Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-55 z 55

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