Journal articles on the topic 'Generalized Essential Matrix'
To see the other types of publications on this topic, follow the link: Generalized Essential Matrix.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Generalized Essential Matrix.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Birkenmeier, Gary F., and Donald D. Davis. "FI-extending generalized matrix rings." Journal of Algebra and Its Applications 19, no. 01 (February 27, 2019): 2050018. http://dx.doi.org/10.1142/s0219498820500188.
Full textAbstract:
Recall that a module [Formula: see text] is FI-extending if every fully invariant submodule is essential in a direct summand of [Formula: see text]. Let [Formula: see text] be a generalized matrix ring, where [Formula: see text] and [Formula: see text] are rings and [Formula: see text] and [Formula: see text] are bimodules. In this paper, we investigate necessary and/or sufficient conditions on [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] for [Formula: see text] to be FI-extending.
2
Miraldo, Pedro, and Helder Araujo. "Generalized essential matrix: Properties of the singular value decomposition." Image and Vision Computing 34 (February 2015): 45–50. http://dx.doi.org/10.1016/j.imavis.2014.11.003.
Full text
3
Kim, Jun-Sik, and Takeo Kanade. "Degeneracy of the Linear Seventeen-Point Algorithm for Generalized Essential Matrix." Journal of Mathematical Imaging and Vision 37, no. 1 (February 12, 2010): 40–48. http://dx.doi.org/10.1007/s10851-010-0191-9.
Full text
4
Kumar, Ashim, Dijana Mosić, Predrag S. Stanimirović, Gurjinder Singh, and Lev A. Kazakovtsev. "Commuting Outer Inverse-Based Solutions to the Yang–Baxter-like Matrix Equation." Mathematics 10, no. 15 (August 2, 2022): 2738. http://dx.doi.org/10.3390/math10152738.
Full textAbstract:
This paper investigates new solution sets for the Yang–Baxter-like (YB-like) matrix equation involving constant entries or rational functional entries over complex numbers. Towards this aim, first, we introduce and characterize an essential class of generalized outer inverses (termed as {2,5}-inverses) of a matrix M, which commute with M. Towards this aim, first, we introduce and characterize an essential class of generalized outer inverses (termed as {2,5}-inverses) of a matrix, which commute with it. This class of {2,5}-inverses is defined based on resolving appropriate matrix equations and inner inverses. In general, solutions to such matrix equations represent optimization problems and require the minimization of corresponding matrix norms. We decided to analytically extend the obtained results to the derivation of explicit formulae for solving the YB-like matrix equation. Furthermore, algorithms for computing the solutions are developed corresponding to the suggested methods in some computer algebra systems. The main features of the proposed approach are highlighted and illustrated by numerical experiments.
5
Lindström, M., S. Miihkinen, and D. Norrbo. "Exact essential norm of generalized Hilbert matrix operators on classical analytic function spaces." Advances in Mathematics 408 (October 2022): 108598. http://dx.doi.org/10.1016/j.aim.2022.108598.
Full text
6
Ferjani, Imen, Aref Jeribi, and Bilel Krichen. "On relative essential spectra of a 3 x 3 operator matrix involving relative generalized weak demicompactness." Filomat 34, no. 13 (2020): 4271–86. http://dx.doi.org/10.2298/fil2013271f.
Full textAbstract:
In this paper, we investigate the relative essential spectra of a 3 x 3 block matrix operator with unbounded entries and with domain consisting of vectors satisfying certain relations between their components. Our results are formulated in term of relative generalized weak demicompactness and measure of non-strict-singularity.
7
Li, Songxiao, and Jizhen Zhou. "Essential norm of generalized Hilbert matrix from Bloch type spaces to BMOA and Bloch space." AIMS Mathematics 6, no. 4 (2021): 3305–18. http://dx.doi.org/10.3934/math.2021198.
Full text
8
Miraldo, Pedro, and João R. Cardoso. "On the Generalized Essential Matrix Correction: An Efficient Solution to the Problem and Its Applications." Journal of Mathematical Imaging and Vision 62, no. 8 (June 6, 2020): 1107–20. http://dx.doi.org/10.1007/s10851-020-00961-w.
Full textAbstract:
Abstract This paper addresses the problem of finding the closest generalized essential matrix from a given $$6\times 6$$ 6 × 6 matrix, with respect to the Frobenius norm. To the best of our knowledge, this nonlinear constrained optimization problem has not been addressed in the literature yet. Although it can be solved directly, it involves a large number of constraints, and any optimization method to solve it would require much computational effort. We start by deriving a couple of unconstrained formulations of the problem. After that, we convert the original problem into a new one, involving only orthogonal constraints, and propose an efficient algorithm of steepest descent type to find its solution. To test the algorithms, we evaluate the methods with synthetic data and conclude that the proposed steepest descent-type approach is much faster than the direct application of general optimization techniques to the original formulation with 33 constraints and to the unconstrained ones. To further motivate the relevance of our method, we apply it in two pose problems (relative and absolute) using synthetic and real data.
9
Wei, Jiao, Xianguo Geng, Xin Wang, and Yunyun Zhai. "Finite genus solutions of the generalized Merola–Ragnisco–Tu lattice hierarchy." Journal of Mathematical Physics 63, no. 8 (August 1, 2022): 083503. http://dx.doi.org/10.1063/5.0088138.
Full textAbstract:
Resorting to the zero-curvature equation and the Lenard recursion equations, the generalized Merola–Ragnisco–Tu lattice hierarchy associated with a 3 × 3 discrete matrix spectral problem is derived. With the aid of the characteristic polynomial of the Lax matrix for the generalized Merola–Ragnisco–Tu lattice hierarchy, a trigonal curve is defined, on which we construct the Baker–Akhiezer function, two meromorphic functions, three kinds of Abelian differentials, and Riemann theta function. By analyzing the asymptotic properties of the Baker–Akhiezer function and two meromorphic functions, especially their asymptotic expansions near three infinite points and three zero points, we obtain their essential singularities and divisors. Finally, we obtain the finite genus solutions of the generalized Merola–Ragnisco–Tu lattice hierarchy in terms of the Riemann theta function.
10
Tian, Yongge. "Characterizations of the group invertibility of a matrix revisited." Demonstratio Mathematica 55, no. 1 (January 1, 2022): 866–90. http://dx.doi.org/10.1515/dema-2022-0171.
Full textAbstract:
Abstract A square complex matrix A A is said to be group invertible if there exists a matrix X X such that A X A = A AXA=A , X A X = X XAX=X , and A X = X A AX=XA hold, and such a matrix X X is called the group inverse of A A . The group invertibility of a matrix is one of the fundamental concepts in the theory of generalized inverses, while group inverses of matrices have many essential applications in matrix theory and other disciplines. The purpose of this article is to reconsider the characterization problem of the group invertibility of a matrix, as well as the constructions of various algebraic equalities in relation to group invertible matrices. The coverage includes collecting and establishing a family of existing and new necessary and sufficient conditions for a matrix to be group invertible and giving many algebraic matrix equalities that involve Moore-Penrose inverses and group inverses of matrices through the skillful use of a series of highly selective formulas and facts about ranks, ranges, and generalized inverses of matrices, as well as block matrix operations.
11
Stanojević, Vukašin, Lev Kazakovtsev, Predrag S. Stanimirović, Natalya Rezova, and Guzel Shkaberina. "Calculating the Moore–Penrose Generalized Inverse on Massively Parallel Systems." Algorithms 15, no. 10 (September 27, 2022): 348. http://dx.doi.org/10.3390/a15100348.
Full textAbstract:
In this work, we consider the problem of calculating the generalized Moore–Penrose inverse, which is essential in many applications of graph theory. We propose an algorithm for the massively parallel systems based on the recursive algorithm for the generalized Moore–Penrose inverse, the generalized Cholesky factorization, and Strassen’s matrix inversion algorithm. Computational experiments with our new algorithm based on a parallel computing architecture known as the Compute Unified Device Architecture (CUDA) on a graphic processing unit (GPU) show the significant advantages of using GPU for large matrices (with millions of elements) in comparison with the CPU implementation from the OpenCV library (Intel, Santa Clara, CA, USA).
12
Birkenmeier, Gary F., Adnan Tercan, and Canan C. Yucel. "Projection invariant extending rings." Journal of Algebra and Its Applications 15, no. 07 (July 22, 2016): 1650121. http://dx.doi.org/10.1142/s0219498816501218.
Full textAbstract:
A ring [Formula: see text] is said to be right [Formula: see text]-extending if every projection invariant right ideal of [Formula: see text] is essential in a direct summand of [Formula: see text]. In this article, we investigate the transfer of the [Formula: see text]-extending condition between a ring [Formula: see text] and its various ring extensions. More specifically, we characterize the right [Formula: see text]-extending generalized triangular matrix rings; and we show that if [Formula: see text] is [Formula: see text]-extending, then so is [Formula: see text] where [Formula: see text] is an overring of [Formula: see text] which is an essential extension of [Formula: see text], an [Formula: see text] upper triangular matrix ring of [Formula: see text], a column finite or column and row finite matrix ring over [Formula: see text], or a certain type of trivial extension of [Formula: see text].
13
SIMA, VASILE. "Numerical solution of stable generalized complex Lyapunov equations." Journal of Engineering Sciences and Innovation 7, no. 1 (March 5, 2022): 71–86. http://dx.doi.org/10.56958/jesi.2022.7.1.71.
Full textAbstract:
Generalized Lyapunov equations are often encountered in systems theory, analysis and design of control systems, and in many applications, including balanced realization algorithms, procedures for reduced order models, or Newton methods for generalized algebraic Riccati equations. An important application is the computation of the Hankel singular values of a generalized dynamical system, whose behavior is defined by a regular matrix pencil (E, A), with E nonsingular. This application uses the controllability and observability Gramians of the system, given as the solutions of a pair of related generalized Lyapunov equations. For a stable system, the solutions of both equations are non-negative definite. The paper summarizes the numerical algorithms for complex continuous- and discrete-time generalized systems. Such solvers are not yet available in the SLICOT Library or MATLAB toolboxes, but could be an important addition. The developed solvers address the essential practical issues of reliability, accuracy, and efficiency.
14
Abbas, Ibrahim A., and Aatef D. Hobiny. "Eigenvalue Approach in a Generalized Thermal Shock Problem for a Transversely Isotropic Half-Space." Journal of Molecular and Engineering Materials 05, no. 01 (March 2017): 1750002. http://dx.doi.org/10.1142/s2251237317500022.
Full textAbstract:
In the present work, the investigating of the disturbances in a homogeneous, transversely isotropic elastic medium with generalized thermoelastic theory has been concerned. The formulation is applied to generalized thermoelasticity based on three different theories. Laplace and Fourier transforms are used to solve the problem analytically. The essential equations have been written as a vector-matrix differential equation in the Laplace transform domain, then solved by an eigenvalue approach. The inverses of Fourier transforms are obtained analytically. The result is used to solve a specific two-dimensional problem. The technique is illustrated by means of several numerical experiments performed. The results were verified numerically and are plotted.
15
Belovas, Igoris, Audrius Kabašinskas, and Leonidas Sakalauskas. "Kovariantiškumas ir kodiferencija sudarant optimalų vertybinių popierių portfelį." Informacijos mokslai 42, no. 43 (January 1, 2008): 182–88. http://dx.doi.org/10.15388/im.2008.0.3422.
Full textAbstract:
Formuojant vertybinių popierių portfelį svarbu nustatyti ryšius tarp atskirų akcijų grąžų. Tačiau laikantis stabilumo prielaidos (modeliuojant akcijų grąžų sekas stabiliaisiais dėsniais) klasikiniai ryšio matai (kovariacija, koreliacija) negali būti taikomi. Todėl apibendrintasis Markovitzo uždavinys yra sprendžiamas su apibendrintais ryšio matais (kovariantiškumas, kodiferencija). Parodyta, kad kodiferencijos tarp atskirų finansinių instrumentų koeficientas gerokai supaprastina portfelio formavimą.Buvo sudaryti Baltijos šalių dešimties vertybinių popierių optimalūs portfeliai.On covariation and Codifference in optimal portfolio constructionIgoris Belovas, Audrius Kabašinskas, Leonidas Sakalauskas SummaryConstructing an optimal portfolio it is essential to determine possible relationships between different stock returns. However, under the assumption of stability (stock returns are modelled with stable laws) accustomed relationship measures covariance, correlation) can not be applied. Thus generalized Markowitz problem is solved with generalized relationship measures (covariation, codifference). Portfolio construction strategies with and without codifference coefficients matrix are given. We show thatthe codifference application strongly simplifies the construction of the optimal portfolio. Optimal stock portfolios (with 10 most realizable Baltic States stocks) with and without codifference coefficients matrix are constructed.
16
Hanvat, Jyoti, and Sumit Sharma. "Optimization of Feature Set for Sentiment Analysis using Artificial Butterfly Algorithm and Ensemble Machine Learning." SMART MOVES JOURNAL IJOSCIENCE 6, no. 11 (November 25, 2020): 21–27. http://dx.doi.org/10.24113/ijoscience.v6i11.325.
Full textAbstract:
The current decade has witnessed the remarkable developments in the field of artificial intelligence, and the revolution of deep learning has transformed the whole artificial intelligence industry. Eventually, deep learning techniques have become essential components of any model in today’s computational world. Nevertheless, ensemble learning techniques promise a high degree of automation with generalized rule extraction for both text and sentiment classification tasks. This paper aims designed and implemented optimized feature matrix using ensemble learning used for sentiment classification and its applications.
17
Wapenaar, Kees, Evert Slob, and Roel Snieder. "On seismic interferometry, the generalized optical theorem, and the scattering matrix of a point scatterer." GEOPHYSICS 75, no. 3 (May 2010): SA27—SA35. http://dx.doi.org/10.1190/1.3374359.
Full textAbstract:
We have analyzed the far-field approximation of the Green’s function representation for seismic interferometry. By writing each of the Green’s functions involved in the correlation process as a superposition of a direct wave and a scattered wave, the Green’s function representation is rewritten as a superposition of four terms. When the scattered waves are modeled with the Born approximation, it appears that a three-term approximation of the Green’s function representation (omitting the term containing the crosscorrelation of the scattered waves) yields a nearly exact retrieval, whereas the full four-term expression leads to a significant nonphysical event. This is because the Born approximation does not conserve energy and therefore is an insufficient model to explain all aspects of seismic interferometry. We use the full four-term expression of the Green’s function representation to derive the generalized optical theorem. Unlike other recent derivations, which use stationary phase analysis, our derivation uses reciprocity theory. From the generalized optical theorem, we derive the nonlinear scattering matrix of a point scatterer. This nonlinear model accounts for primary and multiple scattering at the point scatterer and conforms with well-established scattering theory of classical waves. The model is essential to explain fully the results of seismic interferometry, even when it is applied to the response of a single point scatterer. The nonlinear scattering matrix also has implications for modeling, inversion, and migration.
18
Ehler, Martin. "Preconditioning Filter Bank Decomposition Using Structured Normalized Tight Frames." Journal of Applied Mathematics 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/861563.
Full textAbstract:
We turn a given filter bank into a filtering scheme that provides perfect reconstruction, synthesis is the adjoint of the analysis part (so-called unitary filter banks), all filters have equal norm, and the essential features of the original filter bank are preserved. Unitary filter banks providing perfect reconstruction are induced by tight generalized frames, which enable signal decomposition using a set of linear operators. If, in addition, frame elements have equal norm, then the signal energy is spread through the various filter bank channels in some uniform fashion, which is often more suitable for further signal processing. We start with a given generalized frame whose elements allow for fast matrix vector multiplication, as, for instance, convolution operators, and compute a normalized tight frame, for which signal analysis and synthesis still preserve those fast algorithmic schemes.
19
Deaett, Louis, and Colin Garnett. "Algebraic conditions and the sparsity of spectrally arbitrary patterns." Special Matrices 9, no. 1 (January 1, 2021): 257–74. http://dx.doi.org/10.1515/spma-2020-0136.
Full textAbstract:
Abstract Given a square matrix A, replacing each of its nonzero entries with the symbol * gives its zero-nonzero pattern. Such a pattern is said to be spectrally arbitrary when it carries essentially no information about the eigenvalues of A. A longstanding open question concerns the smallest possible number of nonzero entries in an n × n spectrally arbitrary pattern. The Generalized 2n Conjecture states that, for a pattern that meets an appropriate irreducibility condition, this number is 2n. An example of Shitov shows that this irreducibility is essential; following his technique, we construct a smaller such example. We then develop an appropriate algebraic condition and apply it computationally to show that, for n ≤ 7, the conjecture does hold for ℝ, and that there are essentially only two possible counterexamples over ℂ. Examining these two patterns, we highlight the problem of determining whether or not either is in fact spectrally arbitrary over ℂ. A general method for making this determination for a pattern remains a major goal; we introduce an algebraic tool that may be helpful.
20
Tian, Qiang, Wenjun Wang, Yingjie Xie, Huaming Wu, Pengfei Jiao, and Lin Pan. "A Unified Bayesian Model for Generalized Community Detection in Attribute Networks." Complexity 2020 (August 29, 2020): 1–15. http://dx.doi.org/10.1155/2020/5712815.
Full textAbstract:
Identification of community structures and the underlying semantic characteristics of communities are essential tasks in complex network analysis. However, most methods proposed so far are typically only applicable to assortative community structures, that is, more links within communities and fewer links between different communities, which ignore the rich diversity of community regularities in real networks. In addition, the node attributes that provide rich semantics information of communities and networks can facilitate in-depth community detection of structural information. In this paper, we propose a novel unified Bayesian generative model to detect generalized communities and provide semantic descriptions simultaneously by combining network topology and node attributes. The proposed model is composed of two closely correlated parts by a transition matrix; we first apply the concept of a mixture model to describe network regularities and then adjust the classic Latent Dirichlet Allocation (LDA) topic model to identify community semantically. Thus, the model can detect broad types of network structure regularities, including assortative structures, disassortative structures, and mixture structures and provide multiple semantic descriptions for the communities. To optimize the objective function of the model, we use an effective Gibbs sampling algorithm. Experiments on a number of synthetic and real networks show that our model has superior performance compared with some baselines on community detection.
21
Zupan, Nina, and Jože Korelc. "Sensitivity analysis based multi-scale methods of coupled path-dependent problems." Computational Mechanics 65, no. 1 (September 18, 2019): 229–48. http://dx.doi.org/10.1007/s00466-019-01762-8.
Full textAbstract:
Abstract In the paper, a generalized essential boundary condition sensitivity analysis based implementation of $$\text {FE}^2$$FE2 and mesh-in-element (MIEL) multi-scale methods is derived as an alternative to standard implementations of multi-scale analysis, where the calculation of Schur complement of the microscopic tangent matrix is needed for bridging the scales. The paper presents a unified approach to the development of an arbitrary MIEL or $$\text {FE}^2$$FE2 computational scheme for an arbitrary path-dependent material model. Implementation is based on efficient first and second order analytical sensitivity analysis, for which automatic-differentiation-based formulation of essential boundary condition sensitivity analysis is derived. A fully consistently linearized two-level path-following algorithm is introduced as a solution algorithm for the multi-scale modeling. Sensitivity analysis allows each macro step to be followed by an arbitrary number of micro substeps while retaining quadratic convergence of the overall solution algorithm.
22
Lee, Kyung Eun, Shiv Bharadwaj, Umesh Yadava, and Sang Gu Kang. "Computational and In Vitro Investigation of (-)-Epicatechin and Proanthocyanidin B2 as Inhibitors of Human Matrix Metalloproteinase 1." Biomolecules 10, no. 10 (September 28, 2020): 1379. http://dx.doi.org/10.3390/biom10101379.
Full textAbstract:
Matrix metalloproteinases 1 (MMP-1) energetically triggers the enzymatic proteolysis of extracellular matrix collagenase (ECM), resulting in progressive skin aging. Natural flavonoids are well known for their antioxidant properties and have been evaluated for inhibition of matrix metalloproteins in human. Recently, (-)-epicatechin and proanthocyanidin B2 were reported as essential flavanols from various natural reservoirs as potential anti-inflammatory and free radical scavengers. However, their molecular interactions and inhibitory potential against MMP-1 are not yet well studied. In this study, sequential absorption, distribution, metabolism, and excretion (ADME) profiling, quantum mechanics calculations, and molecular docking simulations by extra precision Glide protocol predicted the drug-likeness of (-)-epicatechin (−7.862 kcal/mol) and proanthocyanidin B2 (−8.145 kcal/mol) with the least reactivity and substantial binding affinity in the catalytic pocket of human MMP-1 by comparison to reference bioactive compound epigallocatechin gallate (−6.488 kcal/mol). These flavanols in docked complexes with MMP-1 were further studied by 500 ns molecular dynamics simulations that revealed substantial stability and intermolecular interactions, viz. hydrogen and ionic interactions, with essential residues, i.e., His218, Glu219, His222, and His228, in the active pocket of MMP-1. In addition, binding free energy calculations using the Molecular Mechanics Generalized Born Surface Area (MM/GBSA) method suggested the significant role of Coulomb interactions and van der Waals forces in the stability of respective docked MMP-1-flavonol complexes by comparison to MMP-1-epigallocatechin gallate; these observations were further supported by MMP-1 inhibition assay using zymography. Altogether with computational and MMP-1–zymography results, our findings support (-)-epicatechin as a comparatively strong inhibitor of human MMP-1 with considerable drug-likeness against proanthocyanidin B2 in reference to epigallocatechin gallate.
23
TANG, ZHENGHUA, and WEIYI ZHANG. "NONRECIPROCAL MULTIFERROIC SUPERLATTICES WITH BROKEN PARITY SYMMETRY." International Journal of Modern Physics B 26, no. 03 (January 30, 2012): 1250021. http://dx.doi.org/10.1142/s021797921250021x.
Full textAbstract:
Multiferroic materials are characterized by the coexistence of ferroelectric and ferromagnetic (or antiferromagnetic) orders, the coupling to lattice vibration can be invoked either through piezoelectric or piezomagnetic effects. In this paper, the polaritonic band structures of multiferroic superlattices composed of oppositely polarized domains are investigated using the generalized transfer matrix method. For the primitive cell with broken parity symmetry, the polaritonic band structure is asymmetrical with respect to the forward and backward propagation directions (nonreciprocality). In particular, the band extreme points move away from the Brillouin zone center. This asymmetry in band-gap positions and widths can be used to design compact one-way optical isolators, while the extremely slow light velocities near the asymmetrical upper edges of lower bands includes the essential ingredients for designing slow light devices.
24
Bai, Tong, and Ilya Tsvankin. "Time-domain finite-difference modeling for attenuative anisotropic media." GEOPHYSICS 81, no. 2 (March 1, 2016): C69—C77. http://dx.doi.org/10.1190/geo2015-0424.1.
Full textAbstract:
Accurate and efficient modeling of seismic wavefields that accounts for both attenuation and anisotropy is essential for further development of processing methods. Here, we present a 2D time-domain finite-difference algorithm for generating multicomponent data in viscoelastic transversely isotropic media with a vertical symmetry axis (VTI). Within the framework of the generalized standard linear solid (GSLS) model, the relaxation function is expressed through the [Formula: see text]-parameters (which quantify the difference between the stress and strain relaxation times) defined for anisotropic media. This approach produces nearly constant values of all components of the quality-factor matrix within a specified frequency band. The developed algorithm is based on a set of anisotropic viscoelastic wave equations parameterized by memory variables. Synthetic examples for TI models with different structural complexity confirm the accuracy of the proposed scheme and illustrate the influence of attenuation and attenuation anisotropy on multicomponent wavefields.
25
FENG, J., and S. WEINBAUM. "Lubrication theory in highly compressible porous media: the mechanics of skiing, from red cells to humans." Journal of Fluid Mechanics 422 (November 3, 2000): 281–317. http://dx.doi.org/10.1017/s0022112000001725.
Full textAbstract:
A generalized lubrication theory that is applicable to highly deformable porous layers is developed using an effective-medium approach (Brinkman equation). This theory is valid in the limit where the structure is so compressible that the normal forces generated by elastic compression of the fibres comprising the solid phase are negligible compared to the pressure forces generated within the porous layer. We assume that the deformation of the solid phase is primarily due to boundary compression as opposed to the motion of the fluid phase. A generalized Reynolds equation is derived in which the spatial variation of the Darcy permeability parameter, α = H/√Kp, due to the matrix compression is determined by new local hydrodynamic solutions for the flow through a simplified periodic fibre model for the deformed matrix. Here H is the undeformed layer thickness and Kp the Darcy permeability. This simplified model assumes that the fibres compress linearly with the deformed gap height in the vertical direction, but the fibre spacing in the horizontal plane remains unchanged. The model is thus able to capture the essential nonlinearity that results from large-amplitude deformations of the matrix layer.The new theory shows that there is an unexpected striking similarity between the gliding motion of a red cell moving over the endothelial glycocalyx that lines our microvessels and a human skier or snowboarder skiing on compressed powder. In both cases one observes an order-of-magnitude compression of the matrix layer when the motion is arrested and predicts values of α that are of order 100. In this large-α limit one finds that the pressure and lift forces generated within the compressed matrix are four orders-of-magnitude greater than classical lubrication theory. In the case of the red cell these repulsive forces may explain why red cells do not experience constant adhesive molecular interactions with the endothelial plasmalemma, whereas in the case of the skier or snowboarder the theory explains why a 70 kg human can glide through compressed powder without sinking to the base as would occur if the motion is arrested. The principal difference between the tightly fitting red cell and the snowboarder is the lateral leakage of the excess pressure at the edges of the snowboard which greatly diminishes the lift force. A simplified axisymmetric model is presented for the red cell to explain the striking pop out phenomenon in which a red cell that starts from rest will quickly lift off the surface and then glide near the edge of the glycocalyx and also for the unexpectedly large apparent viscosity measured by Pries et al. (1994) in vivo.
26
Asefpour Vakilian, A., and M. R. Saradjian. "OPTIMIZATION OF THE SPARSE REPRESENTATION PARAMETERS FOR THE FUSION OF REMOTELY SENSED SATELLITE IMAGES." ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences X-4/W1-2022 (January 13, 2023): 71–77. http://dx.doi.org/10.5194/isprs-annals-x-4-w1-2022-71-2023.
Full textAbstract:
Abstract. Image fusion methods are widely used in remote sensing applications to obtain more information about the features in the study area. One of the recent satellite image fusion techniques that can deal with noise and reduce computational cost and deal with geometric misregistration is sparse representation model. The important part of creating a generalized sparse representation model for satellite image fusion problems is defining initial constraints and adjusting the corresponding regularization coefficients. Regularization coefficients play an essential role in the performance of the sparse representation model and convergence of the optimization solution. Also, the number and size of sub-images extracted from the dictionary matrix in the sparse representation model, and the number of iterations of the optimization step are important in building a sparse representation model. Therefore, in this research, the four parameters that affect the performance of the sparse representation model were investigated: the number of sub-images, the size of sub-images, regularization coefficients, and the number of iterations. Results obtained from pan-sharpening of OLI-8 images showed that optimal values for the number and size of sub-images, regularization coefficients, and the number of iterations were equal to 150, 9×9 pixels, 10-4, and 4 respectively. Results from this study can be generalized to other satellite image fusion problems using sparse representation models.
27
Bonsu, Kwadwo Osei. "Axiomatic Formulation of the Optimal Transaction Cost Theory in the Legal Process Through Cobb-Douglas Optimization." Economic and Regional Studies / Studia Ekonomiczne i Regionalne 14, no. 3 (September 1, 2021): 385–89. http://dx.doi.org/10.2478/ers-2021-0027.
Full textAbstract:
Abstract Subject and purpose of work: This paper uses Cobb-Douglas optimization to formulate an optimal transaction cost algorithm within the constraint of a generalized legal framework. Materials and methods: The author has adopted a Lagrangian approach to formulate the social utility function, then, from a set of legally allowed strategies established the Karush-Kuhn-Tucker conditions for the legal game so as to find the optimal parameters within the social utility function. Finally, the optimal transaction cost algorithm was developed. Results: The Bordered Hessian Matrix from the partial differentials of the social utility function showed that there is a particular parameter within the social utility function which describes the optimal transaction cost. An adjustment of this parameter is essential in mechanism design for legal games. Conclusions: The author has shown how transaction costs influence the set of strategies played by players in a legal game, and has described the essence of a social utility function and how it can be optimized.
28
Birkenmeier, Gary F., and Richard L. LeBlanc. "s.Baer and s.Rickart Modules." Journal of Algebra and Its Applications 14, no. 08 (April 27, 2015): 1550131. http://dx.doi.org/10.1142/s0219498815501315.
Full textAbstract:
In this paper, we study module theoretic definitions of the Baer and related ring concepts. We say a module is s.Baer if the right annihilator of a nonempty subset of the module is generated by an idempotent in the ring. We show that s.Baer modules satisfy a number of closure properties. Under certain conditions, a torsion theory is established for the s.Baer modules, and we provide examples of s.Baer torsion modules and modules with a nonzero s.Baer radical. The other principal interest of this paper is to provide explicit connections between s.Baer modules and projective modules. Among other results, we show that every s.Baer module is an essential extension of a projective module. Additionally, we prove, with limited and natural assumptions, that in a generalized triangular matrix ring every s.Baer submodule of the ring is projective. As an application, we show that every prime ring with a minimal right ideal has the strong summand intersection property. Numerous examples are provided to illustrate, motivate, and delimit the theory.
29
Gupta, V., A. S. Argon, and Z. Suo. "Crack Deflection at an Interface Between Two Orthotopic Media." Journal of Applied Mechanics 59, no. 2S (June 1, 1992): S79—S87. http://dx.doi.org/10.1115/1.2899511.
Full textAbstract:
To achieve toughness in many brittle composites, crack deflection at interfaces is essential. For this, it is necessary to establish crack deflection criteria by employing the principles of interfacial fracture mechanics applicable to anisotropic pair of materials. Such an analysis, with two aligned orthotropic media, is considered here. The stress and deformation fields derived for such cases are shown to depend on material parameters λ and p for the two media and on the two so-called Dundur constants α and β. For β = 0, the dependence on λ and λ2 collapses to Λ = (λ1,/λ2)1/4. The delamination criterion is insensitive to λ, p, Λ, and β over practical ranges of these material parameters. Thus, generalized delamination charts become possible as a function of the bi-material constant a alone, which characterizes the elastic dissimilarity between the two media. Using these charts, it is possible to determine the desired level of the interface strength required in composite manufacturing in order to enhance the overall toughness of a composite. Furthermore, such charts can be used for the interfaces between fiber/coating, fiber /matrix, or matrix/coating, depending on which interface is of critical interest for the crack deflection. It is shown how these charts can be used to identify composite systems where it is possible to maximize both the transverse strength and the longitudinal toughness.
30
Maksimov, Vladimir P. "To estimating linear functionals values over solutions of systems with aftereffect." Russian Universities Reports. Mathematics, no. 131 (2020): 274–83. http://dx.doi.org/10.20310/2686-9667-2020-25-131-274-283.
Full textAbstract:
For a wide class of linear functional differential systems with Volterra operators, a constructive technique is proposed to obtain estimates of linear functionals values over solutions in conditions of uncertainty of external perturbations. It can be applied to solutions of boundary value problems with arbitrary number of boundary conditions as well as to description of attainability sets in control problems with respect to given on-target functionals. External perturbations are constrained by a given linear inequalities system on the main time segment. The technique is based on the results of general theory of functional differential equations about the solvability of boundary value problems with general linear boundary conditions and the representation of solutions. The problem under consideration is reduced to the generalized moment problem. Therewith the results on the properties of the Cauchy matrix to systems with aftereffect are of essential importance. The general form of functionals allows one to cover many cases being topical in applications such as multipoint, integral ones, as well as hybrids of those.
31
ICHIKI, KENGO. "Improvement of the Stokesian Dynamics method for systems with a finite number of particles." Journal of Fluid Mechanics 452 (February 10, 2002): 231–62. http://dx.doi.org/10.1017/s0022112001006735.
Full textAbstract:
An improvement of the Stokesian Dynamics method for many-particle systems is presented. A direct calculation of the hydrodynamic interaction is used rather than imposing periodic boundary conditions. The two major difficulties concern the accuracy and the speed of calculations. The accuracy discussed in this work is not concerned with the lubrication correction but, rather, focuses on the multipole expansion which until now has only been formulated up to the so-called FTS version or the first order of force moments. This is improved systematically by a real-space multipole expansion with force moments and velocity moments evaluated at the centre of the particles, where the velocity moments are calculated through the velocity derivatives; the introduction of the velocity derivatives makes the formulation and its extensions straightforward. The reduction of the moments into irreducible form is achieved by the Cartesian irreducible tensor. The reduction is essential to form a well-defined linear set of equations as a generalized mobility problem. The order of truncation is not limited in principle, and explicit calculations of two-body problems are shown with order up to 7. The calculating speed is improved by a conjugate-gradient-type iterative method which consists of a dot-product between the generalized mobility matrix and the force moments as a trial value in each iteration. This provides an O(N2) scheme where N is the number of particles in the system. Further improvement is achieved by the fast multipole method for the calculation of the generalized mobility problem in each iteration, and an O(N) scheme for the non-adaptive version is obtained. Real problems are studied on systems with N = 400 000 particles. For mobility problems the number of iterations is constant and an O(N) performance is achieved; however for resistance problems the number of iterations increases as almost N1/2 with a high accuracy of 10−6 and the total cost seems to be O(N3/2).
32
Lee, Yi-Hsi, Ming-Hua Hsieh, Weiyu Kuo, and Chenghsien Jason Tsai. "How can an economic scenario generation model cope with abrupt changes in financial markets?" China Finance Review International 11, no. 3 (May 31, 2021): 372–405. http://dx.doi.org/10.1108/cfri-03-2021-0056.
Full textAbstract:
PurposeIt is quite possible that financial institutions including life insurance companies would encounter turbulent situations such as the COVID-19 pandemic before policies mature. Constructing models that can generate scenarios for major assets to cover abrupt changes in financial markets is thus essential for the financial institution's risk management.Design/methodology/approachThe key issues in such modeling include how to manage the large number of risk factors involved, how to model the dynamics of chosen or derived factors and how to incorporate relations among these factors. The authors propose the orthogonal ARMA–GARCH (autoregressive moving-average–generalized autoregressive conditional heteroskedasticity) approach to tackle these issues. The constructed economic scenario generation (ESG) models pass the backtests covering the period from the beginning of 2018 to the end of May 2020, which includes the turbulent situations caused by COVID-19.FindingsThe backtesting covering the turbulent period of COVID-19, along with fan charts and comparisons on simulated and historical statistics, validates our approach.Originality/valueThis paper is the first one that attempts to generate complex long-term economic scenarios for a large-scale portfolio from its large dimensional covariance matrix estimated by the orthogonal ARMA–GARCH model.
33
Guedes, Marcello Barbosa Otoni Gonçalves, Sanderson José Costa de Assis, Geronimo José Bouzas Sanchis, Diego Neves Araujo, Angelo Giuseppe Roncalli Da Costa Oliveira, and Johnnatas Mikael Lopes. "COVID-19 in Brazilian cities: Impact of social determinants, coverage and quality of primary health care." PLOS ONE 16, no. 9 (September 17, 2021): e0257347. http://dx.doi.org/10.1371/journal.pone.0257347.
Full textAbstract:
Background Brazil, as many other countries, have been heavily affected by COVID-19. This study aimed to analyze the impact of Primary health care and the family health strategy (FHS) coverage, the scores of the National Program for Improving Primary Care Access and Quality (PMAQ), and socioeconomic and social indicators in the number of COVID-19 cases in Brazilian largest cities. Methods This is an ecological study, carried out through the analysis of secondary data on the population of all Brazilian main cities, based on the analysis of a 26-week epidemiological epidemic week series by COVID-19. Statistical analysis was performed using Generalized Linear Models with an Autoregressive work correlation matrix. Results It was shown that greater PHC coverage and greater FHS coverage together with an above average PMAQ score are associated with slower dissemination and lower burden of COVID-19. Conclusion It is evident that cities with less social inequality and restrictions of social protection combined with social development have a milder pandemic scenario. It is necessary to act quickly on these conditions for COVID-19 dissemination by timely actions with high capillarity. Expanding access to PHC and social support strategies for the vulnerable are essential.
34
Yasin, Hasbi, Budi Warsito, Rukun Santoso, and Arief Rachman Hakim. "Forecasting of Rainfall in Central Java using Hybrid GSTAR-NN-PSO Model." E3S Web of Conferences 125 (2019): 23015. http://dx.doi.org/10.1051/e3sconf/201912523015.
Full textAbstract:
Forecasting of rainfall trends is essential for several fields, such as airline and ship management, flood control and agriculture. The rainfall data were recorded several time simultaneously at a number of locations and called the space-time data. Generalized Space Time Autoregressive (GSTAR) model is one of space-time models used to modeling and forecasting the rainfall. The aim of this research is to propose the nonlinear space-time model based on hybrid of GSTAR, Feed Forward Neural Network (FFNN) and Particle Swarm Optimization (PSO) and it called GSTAR-NN-PSO. In this model, input variable of the FFNN was obtained from the GSTAR model. Then use PSO to initialize the weight parameter in the FFNN model. This model is applied for forecasting monthly rainfall data in Jepara, Kudus, Pati and Grobogan, Central Java, Indonesia. The results show that the proposed model gives more accurate forecast than the linear space-time model, i.e. GSTAR and GSTAR-PSO. Moreover, further research about space-time models based on GSTAR and Neural Network is needed to improving the forecast accuracy especially the weight matrix in the GSTAR model.
35
Baral, Pratyusava, Soumendra Kishore Roy, and Supratik Pal. "Prospects of probing dark energy with eLISA: Standard versus null diagnostics." Monthly Notices of the Royal Astronomical Society 500, no. 3 (October 29, 2020): 2896–907. http://dx.doi.org/10.1093/mnras/staa3346.
Full textAbstract:
ABSTRACT Gravitational waves from supermassive black hole binary mergers along with an electromagnetic counterpart have the potential to shed ‘light’ on the nature of dark energy in the intermediate redshift regime. Accurate measurement of dark energy parameters at intermediate redshift is extremely essential to improve our understanding of dark energy, and to possibly resolve a couple of tensions involving cosmological parameters. We present a Fisher matrix forecast analysis in the context of eLISA to predict the errors for three different cases: the non-interacting dark energy with constant and evolving equation of state (EoS), and the interacting dark sectors with a generalized parametrization. In all three cases, we perform the analysis for two separate formalisms, namely, the standard EoS formalism and the Om parametrization which is a model-independent null diagnostic for a wide range of fiducial values in both phantom and non-phantom regions, to make a comparative analysis between the prospects of these two diagnostics in eLISA. Our analysis reveals that it is wiser and more effective to probe the null diagnostic instead of the standard EoS parameters for any possible signature of dark energy at intermediate redshift measurements like eLISA.
36
Badulin, Sergei I., Victor I. Shrira, Christian Kharif, and Mansour Ioualalen. "On two approaches to the problem of instability of short-crested water waves." Journal of Fluid Mechanics 303 (November 25, 1995): 297–326. http://dx.doi.org/10.1017/s0022112095004289.
Full textAbstract:
The work is concerned with the problem of the linear instability of symmetric short-crested water waves, the simplest three-dimensional wave pattern. Two complementary basic approaches were used. The first, previously developed by Ioualalen & Kharif (1993, 1994), is based on the application of the Galerkin method to the set of Euler equations linearized around essentially nonlinear basic states calculated using the Stokes-like series for the short-crested waves with great precision. An alternative analytical approach starts with the so-called Zakharov equation, i.e. an integro-differential equation for potential water waves derived by means of an asymptotic procedure in powers of wave steepness. Both approaches lead to the analysis of an eigenvalue problem of the type {\rm det}|{\boldmath A}-\gamma{\boldmath B}|=0 where A and B are infinite square matrices. The first approach should deal with matrices of quite general form although the problem is tractable numerically. The use of the proper canonical variables in our second approach turns the matrix B into the unit one, while the matrix A gets a very specific ‘nearly diagonal’ structure with some additional (Hamiltonian) properties of symmetry. This enables us to formulate simple necessary and sufficient a priori criteria of instability and to find instability characteristics analytically through an asymptotic procedure avoiding a number of additional assumptions that other authors were forced to accept.A comparison of the two approaches is carried out. Surprisingly, the analytical results were found to hold their validity for rather steep waves (up to steepness 0.4) for a wide range of wave patterns. We have generalized the classical Phillips concept of weakly nonlinear wave instabilities by describing the interaction between the elementary classes of instabilities and have provided an understanding of when this interaction is essential. The mechanisms of the relatively high stability of short-crested waves are revealed and explained in terms of the interaction between different classes of instabilities. A helpful interpretation of the problem in terms of an infinite chain of interacting linear oscillators was developed.
37
Giordano, Bryan V., Anthony Cruz, Daniel W. Pérez-Ramos, Martina M. Ramos, Yasmin Tavares, and Eric P. Caragata. "Mosquito Communities Vary across Landscape and Vertical Strata in Indian River County, Florida." Pathogens 10, no. 12 (December 3, 2021): 1575. http://dx.doi.org/10.3390/pathogens10121575.
Full textAbstract:
Mosquito and arbovirus surveillance is essential to the protection of public health. A majority of surveys are undertaken at ground level. However, mosquitoes shelter, breed, and quest for hosts across vertical strata, thus limiting our ability to fully describe mosquito and arboviral communities. To elucidate patterns of mosquito vertical stratification, canopy traps were constructed to sample mosquitoes at heights of 1.5, 5.0, and 8.7 m across three different landscape types in a Florida coastal conservation area. We assessed trapping efforts using individual-based rarefaction and extrapolation. The effects of height, landscape, site location, and sampling date on mosquito community composition were parsed out using permutational ANOVA on a Hellinger-transformed Bray–Curtis dissimilarity abundance matrix. Lastly, a generalized linear mixed effects model (GLMM) was used to explore species-specific vertical patterns. We observed differences in sampling effort and community composition structure across various heights and landscapes. Our GLMM revealed significant effects of trap height for Aedes taeniorhynchus, Anopheles crucians, Anopheles quadrimaculatus, and Culex coronator, but not for Culex nigripalpus, the ultra-dominant species present in this area. Together these data provide evidence that height and landscape significantly affect mosquito community structures and highlight a need to develop sampling regimes to target specific vector and nuisance species at their preferred height and across different landscape types.
38
Novachenko, T. V. "Public imagination as a modern mechanism of solidarization in the Ukrainian nation." Ukrainian Society 81, no. 2 (June 28, 2022): 51–58. http://dx.doi.org/10.15407/socium2022.02.051.
Full textAbstract:
The article is devoted to the pressing issue of defining modern solidarity mechanisms in the Ukrainian nation, one of which is the public imagination. The methodological basis of the presented intelligence is the scientific work of C.G. Jung, the founder of one of the philosophical concepts of the collective unconscious; the work of French scientist – G. Durand, author of the concept of l’imaginaire – imaginary, who emphasizes that the world around us is the result of a free play of imagination, and modern French sociologist M. Maffesoli, – a cross-cutting problem of his research also poses the phenomenon of its social imaginary embodiment in social and symbolic forms, and several Ukrainian architects – E. Afonin, D. Zaiets, A. Martynov, V. Pliushch, V. Tancher. Based on the analysis of the presented works, the author has obtained the basis for developing a unique “ontology of the imager” – an imaginary image that is always specific. One or another “colour” of the imaginary image gives the semantic meanings that a person remembers following particular objects of reality, including political, as well as a generalized imaginary image as an ideal of actions, thoughts, feelings, and behaviour corresponding to the archetype “Self”, determining the psychological integrity of the individual. It has been confirmed that a person remembers only the most essential characteristics of an object, which constitute a “complete” imaginary image. Still they may lose touch with a particular object, retaining its typical features. This fact makes it possible to state that the type of generalized imaginary image appears as a social imaginary that influences reality creation. At the same time, due to horizontal social ties and the diversity of the individual imagination, “organic” (according to E. Durkheim) solidarity is achieved, which is a kind of strategy to mobilize society, especially in times of severe crises or threats. The public imagination is a “complete” imaginary image, which may lose touch with a particular object but retain its typical features, which allows us to determine its archetypal matrix and modern mechanism of solidarity of the Ukrainian nation.
39
Andrade, Rodrigo Soares de. "Amelogenesis Imperfecta from Diagnosis to Rehabilitation-A Case Report." International Journal of Clinical Case Reports and Reviews 7, no. 03 (June 25, 2021): 01–06. http://dx.doi.org/10.31579/2690-4861/127.
Full textAbstract:
During odontogenesis, enamel is normally synthesized as an extracellular matrix, a phenomenon known as amelogenesis. The failure of this process can lead to malformation of dental enamel, called Amelogenesis Imperfecta (AI). AI, by causing a qualitative and/or quantitative deficiency of dental enamel, presents characteristics such as hypersensitivity, unsatisfactory aesthetics, reduced vertical dimension, anterior open bite, plaque accumulation, and greater susceptibility to caries and gingivitis. Thus, our objective is to report a case of AI, describing the main characteristics of the disease, the diagnosis and the rehabilitative treatment plan, aiming to improve the patient's aesthetics and reestablishing the function of the stomatognathic system. Patient M.A.S.B., female, 5 years old, leucoderma, was admitted at the University of Patos de Minas Dental Clinic with a complaint of pain in the teeth. During the clinical interview, the person in charge reported that the child's teeth had the same defects as those of her mother and brother. During clinical examination it was observed: generalized loss of tooth structure, color change, rough surfaces and hypersensitivity. Treatment involved restorations with glass ionomer cement and composite resin, extraction of residual roots from the maxillary incisors, and confection of a functional and aesthetic space maintainer. Early diagnosis associated with the correct treatment plan is essential for a more conservative approach focused on preventing the effects of AI. In advanced cases, restoring function and aesthetics is paramount to improve the patient's quality of life.
40
Kalibernova, N. M. "Showing the vegetation cover of flood-plains and river valleys on the Vegetation Map of Kazakhstan and middle Asia." Geobotanical mapping, no. 1993 (1995): 58–66. http://dx.doi.org/10.31111/geobotmap/1993.58.
Full textAbstract:
The fragment of the legend of the map concerning the vegetation of flood- plains and river-valleys in the subzones of northern and southern deserts is presented in the article. The map is compiled in Department of Vegetspon Geography and Cartography of Komarov Botanical Institute by a large team of botanists-geographers of the former USSR. The nature environments determining the development of vegetation of river-valleys in arid climate are conditioned by the intrazonal factors (alluvial and flood processes) at the background of natural zonal factors. Contrasts of environments and corresponding plant communities manifest themselves first of all. Mineralization of ground waters, salinity of soils, including the alluvial ones, are of essential importance. The practice of vegetation mapping of unstable habitats, to which floodplain landscapes belong, has shown that units of phytocoenological classification is of little use for this purpose. The heterogeneity of vegetation, consisting of short-term unstable serial communities generates a need for typification of space combinations of such phytocoenoses. For this purpose it is convenient to use generalized ecological-dinamic series, including plant communities of all levels within the limits of definite segment of valley. These series are the mapping units on the map. The vegetation of the first terrace is also nessecary to include in a single series with flood-plain vegetation because it has supplementary influence of ground waters. The higher divisions of the legend are based on zonal characters: vegetation of valleys in northern, middle and southern deserts. 13 numbers are used to show the vegetation cover of flood-plains and valleys. Additional 7 numbers are used for the out-of-valley meadow vegetation. The content is enriched by using of the letters by the numbers showing the geographic variants of series and ciphers for combination of series and out-of-series communities. The text legend is supplemented by the matrix (table), showing the subordination of subtitles, zonal position and geographic distribution of divisions. The types of series in the matrix are listed with indication of the main dominant species that gives the additional information on the legend divisions. The author's conclusion is that valley vegetation reveals clearly the zonal features, correlating with zonal (desert) vegetation.
41
Petrescu, Florian Ion Tiberiu, and Relly Victoria Virgil Petrescu. "ABOUT THE ANTHROPOMORPHIC ROBOTS." Engevista 17, no. 1 (May 9, 2014): 1. http://dx.doi.org/10.22409/engevista.v17i1.565.
Full textAbstract:
The paper presents an original geometrical and kinematic method for the study of geometry and determining positions of a MP-3R structure of the anthropomorphic robots. It presents shortly the MP-3R direct and inverse kinematics, the inverse kinematics being solved by an original exactly method. One presents shortly an original method to solve the robot inverse kinematics exemplified at the 3R-Robots (MP-3R). The system which must be solved has three equations and three independent parameters to determine. Constructive basis is represented by a robot with three degrees of freedom (a robot with three axes of rotation). If we study (analyze) an anthropomorphic robot with three axes of rotation (which represents the main movements, absolutely necessary), we already have a base system, on which we can then add other movements (secondary, additional). Calculations were arranged and in the matrix form. The most commonly used serial structures over the last 20 or 30 years are those of type 3R, 4R, 5R, 6R, having as constituents essential basic kinematic chain 3R, robot anthropomorphic (RRR), where main rotation around a vertical axis, causes the construction. It can thus passes from the study spatial movement, which is more difficult, to the study motion plane, basic movement, for all the robots and fillers serial movements of rotation. Moving flat, horizontal or vertical, shall be undertaken far more easily than the spatial integration with the convenience simple in the space of which it is part. We will exemplify the basic structure existing in a few serial platforms of rotation, these being the most generalized (more widespread) at the present time. In this work will be pursued and the direct and inverse kinematics of these mechanical systems. It can make the transition from 3R systems-level 2R and vice versa.
42
Capone, Cristiano, Paolo Muratore, and Pier Stanislao Paolucci. "Error-based or target-based? A unified framework for learning in recurrent spiking networks." PLOS Computational Biology 18, no. 6 (June 21, 2022): e1010221. http://dx.doi.org/10.1371/journal.pcbi.1010221.
Full textAbstract:
The field of recurrent neural networks is over-populated by a variety of proposed learning rules and protocols. The scope of this work is to define a generalized framework, to move a step forward towards the unification of this fragmented scenario. In the field of supervised learning, two opposite approaches stand out, error-based and target-based. This duality gave rise to a scientific debate on which learning framework is the most likely to be implemented in biological networks of neurons. Moreover, the existence of spikes raises the question of whether the coding of information is rate-based or spike-based. To face these questions, we proposed a learning model with two main parameters, the rank of the feedback learning matrix R and the tolerance to spike timing τ⋆. We demonstrate that a low (high) rank R accounts for an error-based (target-based) learning rule, while high (low) tolerance to spike timing promotes rate-based (spike-based) coding. We show that in a store and recall task, high-ranks allow for lower MSE values, while low-ranks enable a faster convergence. Our framework naturally lends itself to Behavioral Cloning and allows for efficiently solving relevant closed-loop tasks, investigating what parameters ( R , τ ⋆ ) are optimal to solve a specific task. We found that a high R is essential for tasks that require retaining memory for a long time (Button and Food). On the other hand, this is not relevant for a motor task (the 2D Bipedal Walker). In this case, we find that precise spike-based coding enables optimal performances. Finally, we show that our theoretical formulation allows for defining protocols to estimate the rank of the feedback error in biological networks. We release a PyTorch implementation of our model supporting GPU parallelization.
43
Ramadori, Giuliano. "Albumin Infusion in Critically Ill COVID-19 Patients: Hemodilution and Anticoagulation." International Journal of Molecular Sciences 22, no. 13 (July 1, 2021): 7126. http://dx.doi.org/10.3390/ijms22137126.
Full textAbstract:
Hypercoagulation is one of the major risk factors for ICU treatment, mechanical ventilation, and death in critically ill patients infected with SARS-CoV-2. At the same time, hypoalbuminemia is one risk factor in such patients, independent of age and comorbidities. Especially in patients with severe SARS-CoV-2-infection, albumin infusion may be essential to improve hemodynamics and to reduce the plasma level of the main marker of thromboembolism, namely, the D-dimer plasma level, as suggested by a recent report. Albumin is responsible for 80% of the oncotic pressure in the vessels. This is necessary to keep enough water within the systemic circulatory system and for the maintenance of sufficient blood pressure, as well as for sufficient blood supply for vital organs like the brain, lungs, heart, and kidney. The liver reacts to a decrease in oncotic pressure with an increase in albumin synthesis. This is normally possible through the use of amino acids from the proteins introduced with the nutrients reaching the portal blood. If these are not sufficiently provided with the diet, amino acids are delivered to the liver from muscular proteins by systemic circulation. The liver is also the source of coagulation proteins, such as fibrinogen, fibronectin, and most of the v WF VIII, which are physiological components of the extracellular matrix of the vessel wall. While albumin is the main negative acute-phase protein, fibrinogen, fibronectin, and v WF VIII are positive acute-phase proteins. Acute illnesses cause the activation of defense mechanisms (acute-phase reaction) that may lead to an increase of fibrinolysis and an increase of plasma level of fibrinogen breakdown products, mainly fibrin and D-dimer. The measurement of the plasma level of the D-dimer has been used as a marker for venous thromboembolism, where a fourfold increase of the D-dimer plasma level was used as a negative prognostic marker in critically ill SARS-CoV-2 hospitalized patients. Increased fibrinolysis can take place in ischemic peripheral sites, where the mentioned coagulation proteins can become part of the provisional clot (e.g., in the lungs). Although critically ill SARS-CoV-2-infected patients are considered septic shock patients, albumin infusions have not been considered for hemodynamic resuscitation and as anticoagulants. The role of coagulation factors as provisional components of the extracellular matrix in case of generalized peripheral ischemia due to hypoalbuminemia and hypovolemia is discussed in this review.
44
Batchenko, Ludmila, Maryna Dielini, and Liliia Honchar. "A VALUE-ORIENTED POLYPARADIGMAL APPROACH TO THE DEVELOPMENT OF MANAGEMENT EDUCATION IN THE CONDITIONS OF TRANSFORMATION CHANGE." Baltic Journal of Economic Studies 6, no. 5 (December 2, 2020): 42–53. http://dx.doi.org/10.30525/2256-0742/2020-6-5-42-53.
Full textAbstract:
The purpose of the article is a theoretical, methodological, and practical justification for the introduction of a value-oriented polyparadigmatic approach to the development of management education. Methodology. Scientific analysis is carried out by an interdisciplinary system of methods: systemic philosophical analysis, structural functional method, generalization, modeling, and others. Results. The known methodological approaches to the formation of modern educational models of management training are considered; the essential concepts of educational paradigms are revealed and the necessity of their generalization is scientifically confirmed; the presence of values in each of them is established, which allowed to justify the polyparadigmatic approach to the development of management education. The most significant scientific results: the author’s definition of the concept “value-oriented polyparadigmatic approach” is proposed, which is based on the understanding of the need to integrate effective educational paradigms based on the correlation of their valuable component in the educational construct of polyparadigmatic approach to management personnel development; principles of valueoriented approach to management activity (the principle of cognitive integrity; methodology; national orientation; axiological mediation; feasibility; polysubjectivity; the principle of statehood; scientific) is defined, the effectiveness of which ensures the complexity of their use at any level of management; axiological functions of the modern education system (ecological, humanistic, cultural heritage, creative, developmental, adaptive) are substantiated, which include certain axiological attitudes, affect the value aspects of training and education of the future manager and are important for the educational system, society, state, individual people in the present and will remain relevant for the future; a matrix of valuable orientations of the subjects of managerial activity is formed, which, according to the functional approach, has generalized the key parameters of determining the bank of competencies of managers. The practical significance of the study is in expanding and supplementing the theoretical and applied knowledge of management; in the possibility to apply knowledge in the educational process in the implementation of a value-oriented polyparadigmatic approach to management education; in use in the preparation of new regulatory and methodological documents on higher management education. Value/originality. The originality of the scientific research is represented by a fundamentally new combination (set) of methodological tools that ensure the uniqueness and value of scientific research.
45
Pai, D. M. "On: “Accurate depth migration by a generalized phase‐shift method” by Dan Kosloff and David Kessler (GEOPHYSICS 52, 1074–1084, August 1987)." GEOPHYSICS 54, no. 2 (February 1989): 271–72. http://dx.doi.org/10.1190/1.1442652.
Full textAbstract:
I would like to point out that the “generalized phase‐shift method” (Kosloff and Kessler, 1987) introduced for solution continuation — and referred to as a new method — is essentially identical to the “generalized Haskell matrix/layer eigenstate propagator (GHM/LEP)” method I presented earlier (Pai, 1985). Unfortunately, Kosloff and Kessler did not reference that paper.
46
Solodov, Alexander A. "Statistical analysis of the formation mechanism of concepts-representations in organizational and technical systems." Statistics and Economics 15, no. 4 (September 4, 2018): 70–76. http://dx.doi.org/10.21686/2500-3925-2018-4-70-76.
Full textAbstract:
The aim of the research is the analytical description of one of the modules of the organizational and technical system, designed for the formation of sensual images and their transformation into concepts-representations. Within the framework of the computer paradigm in organizational and technical systems, such obvious principles as digital representation of information and its processing with the use of algorithms implemented by computing means are used. The success of the computer paradigm application is certainly impressive, but there are clearly situations in which human consciousness operates much more efficiently, interpreting the unconventional, the new situation with the aim of formulating an adequate response. In this regard, attempts to model some mechanisms of human consciousness within the framework of the cognitive approach are of great interest. In accordance with the ideas of cognitive theory in the human brain, images (schemes, categories, gestalts, systems, archetypes, etc.) are formed and then are processed. It is assumed that the resulting images are those effects that are then processed, perceived, used by the organizational and technical system for the formation of concepts-representations. Concept representation is a generalized sensual-visual image of the object or phenomenon and is characterized by a number of features, the number of which may vary in the course of the system operation.The method of Markov chains is used to study the statistical characteristics of the mechanism of formation of concepts-representations. It is assumed that the formation of sensual images and their transformation into concepts-representations occurs at random moments of time. The module of concept-representation formation can be in one of two states that correspond to the logic of its functioning – either its state does not change, or when a new concept-representation is formed, the state of the module changes. A stochastic matrix of one step transient probabilities, characterizing changes in the module states and corresponding initial probabilities of states is introduced. Because of application of the theory of Markov chains with two states, the relations for the probabilities of the module states through an arbitrary number of steps, as well as asymptotic expressions for the probabilities of states are given. The graphs of the module state probabilities change depending on the number of circuit steps, initial probabilities, probabilities of one-step transitions of the stochastic matrix are presented.Analytical expressions and corresponding graphs for the average number of stays in the module of a particular state are obtained, which are interpreted as the average number of corrections of essential features of concepts-representations. The asymptotic relations for the number of corrections are obtained, and the error of the approximate asymptotic relations is estimated.Thus, the paper formulates a very general model of the random process of formation of sensual images and their transformation into concepts-representations. The key task of the practical application of the model is to analyze the logic of the functioning of a particular organizational and technical system and to determine on this basis the parameters appearing in the model.
47
Christiansen, Oddvar, Tin-Man Lee, Johan Lie, Usha Sinha, and Tony F. Chan. "Total Variation Regularization of Matrix-Valued Images." International Journal of Biomedical Imaging 2007 (2007): 1–11. http://dx.doi.org/10.1155/2007/27432.
Full textAbstract:
We generalize the total variation restoration model, introduced by Rudin, Osher, and Fatemi in 1992, to matrix-valued data, in particular, to diffusion tensor images (DTIs). Our model is a natural extension of the color total variation model proposed by Blomgren and Chan in 1998. We treat the diffusion matrixDimplicitly as the productD=LLT, and work with the elements ofLas variables, instead of working directly on the elements ofD. This ensures positive definiteness of the tensor during the regularization flow, which is essential when regularizing DTI. We perform numerical experiments on both synthetical data and 3D human brain DTI, and measure the quantitative behavior of the proposed model.
48
Chuiko, Sergei, and Olga Nesmelova. "About the equilibrium positions of a matrix differential-algebraic boundary value problem." Proceedings of the Institute of Applied Mathematics and Mechanics NAS of Ukraine 33 (December 27, 2019): 218–31. http://dx.doi.org/10.37069/1683-4720-2019-33-17.
Full textAbstract:
In the article we found the solvability conditions and the construction of the generalized Green operator of the linear Noetherian matrix differential-algebraic boundary value problem. We obtained sufficient conditions of transformationsof the matrix differential-algebraic equation to a traditional differential-algebraic equation with an unknown in the form of a column vector. The problem that reviewed in the article continues the study of solvability conditions for the linear Noetherian boundary value problems given in the monographs of M.V. Azbelev, V.P. Maksimov, L.F. Rakhmatullina, A.M. Samoilenko and A.A. Boichuk. We investigated the general case when the linear bounded operator corresponding to the homogeneous part of the linear Cauchy problem for the matrix differential-algebraic system does not have the reverse operator. We introduced the definition of the equilibrium positions of the matrix differential-algebraic system and the matrix differential-algebraic boundary-value problem to solve the matrix differential-algebraic boundary-value problem. We proposed sufficient conditions of existence and constructive schemes for finding the equilibrium positions of the matrix differential-algebraic system and the matrix differential-algebraic boundary value problem. The cases~of equilibrium positions of the matrix differential-algebraic system, which are constant matrices, and equilibrium positions depending on an independent variable are considered separately. To solve the matrix differential-algebraic boundary-value problem, we used the original solvability conditions and~the construction of the general solution of the Sylvester-type matrix equation, while the Moore-Penrose matrix pseudoinverse technique was essentially used. In the article we constructed the generalized Green operator of the linear Noetherian matrix differential-algebraic boundary value problem. The proposed solvability conditions and the construction of the generalized Green operator of the linear Noetherian matrix differential-algebraic boundary value problem, were illustrated in detail with examples.
49
Hetyei, Gábor. "Meixner polynomials of the second kind and quantum algebras representing su(1, 1)." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 466, no. 2117 (December 16, 2009): 1409–28. http://dx.doi.org/10.1098/rspa.2009.0497.
Full textAbstract:
We show how Viennot’s combinatorial theory of orthogonal polynomials may be used to generalize some recent results of Sukumar and Hodges (Hodges & Sukumar 2007 Proc. R. Soc. A 463 , 2401–2414 ( doi:10.1098/rspa.2007.0001 ); Sukumar & Hodges 2007 Proc. R. Soc. A 463 , 2415–2427 ( doi:10.1098/rspa.2007.0003 )) on the matrix entries in powers of certain operators in a representation of su(1, 1). Our results link these calculations to finding the moments and inverse polynomial coefficients of certain Laguerre polynomials and Meixner polynomials of the second kind. As an immediate consequence of results by Koelink, Groenevelt and Van Der Jeugt (Van Der Jeugt 1997 J. Math. Phys. 38 , 2728–2740 ( doi:10.1063/1.531984 ); Koelink & Van Der Jeugt 1998 SIAM J. Math. Anal. 29 , 794–822 ( doi:10.1137/S003614109630673X ); Groenevelt & Koelink 2002 J. Phys. A 35 , 65–85 ( doi:10.1088/0305-4470/35/1/306 )), for the related operators, substitutions into essentially the same Laguerre polynomials and Meixner polynomials of the second kind may be used to express their eigenvectors. Our combinatorial approach explains and generalizes this ‘coincidence’.
50
FUJII, KAZUYUKI, KUNIO FUNAHASHI, and TAKAYUKI KOBAYASHI. "JARLSKOG'S PARAMETRIZATION OF UNITARY MATRICES AND QUDIT THEORY." International Journal of Geometric Methods in Modern Physics 03, no. 02 (March 2006): 269–83. http://dx.doi.org/10.1142/s0219887806001144.
Full textAbstract:
In the paper (math–ph/0504049) Jarlskog gave an interesting simple parametrization to unitary matrices, which was essentially the canonical coordinate of the second kind in the Lie group theory (math–ph/0505047). In this paper we apply the method to a quantum computation based on multilevel system (qudit theory). Namely, by considering that the parametrization gives a complete set of modules in qudit theory, we construct the generalized Pauli matrices, which play a central role in the theory and also make a comment on the exchange gate of two–qudit systems. Moreover, we give an explicit construction to the generalized Walsh–Hadamard matrix in the case of n = 3, 4, and 5. For the case of n = 5, its calculation is relatively complicated. In general, a calculation to construct it tends to become more and more complicated as n becomes large. To perform a quantum computation the generalized Walsh–Hadamard matrix must be constructed in a quick and clean manner. From our construction it may be possible to say that a qudit theory with n ≥ 5 is not realistic. This paper is an introduction toward Quantum Engineering.