Search results for "Matrix"
showing 10 items of 3205 documents
Construction of a fundamental set of solutions of an arbitrary homogeneous linear difference equation
2002
Abstract The detailed construction of a prefixed fundamental set of solutions of a linear homogeneous difference equation of any order with arbitrarily variable coefficients is reported. The usefulness of the resulting resolutive formula is illustrated by simple applications to the Hermite polynomials and to the Fibonacci sequence.
Improvement of matrix solutions of generalized nonlinear wave equation
2005
Four classes of nonlinear wave equations are joined in one generalized nonlinear wave equation. A theorem is proved that the whole series of matrix functions satisfy the generalized wave equation. A justification of rotational properties of matrix solutions is given and a mathematical model of the ring vortex around the acute edge is proposed using of matrix solutions.
Computing continuous numerical solutions of matrix differential equations
1995
Abstract In this paper, we construct analytical approximate solutions of initial value problems for the matrix differential equation X ′( t ) = A ( t ) X ( t ) + X ( t ) B ( t ) + L ( t ), with twice continuously differentiable functions A ( t ), B ( t ), and L ( t ), continuous. We determine, in terms of the data, the existence interval of the problem. Given an admissible error e, we construct an approximate solution whose error is smaller than e uniformly, in all the domain.
Pharmacologic therapies in endometriosis: a systematic review
2012
To assess the literature on preclinical and clinical efficacy and safety data of pharmacologic groups proposed in the treatment of endometriosis, we performed a systematic review of publications from March 2002 to January 2012 via PubMed search. Additional relevant articles were identified from citations within these publications. A high number of medications were tested in preclinical models of endometriosis due to their theoretic capacity of disrupting important pathophysiologic pathways of the disease, such as inflammatory response, angiogenesis and cell survival, proliferation, migration, adhesion, and invasion. Tumor necrosis factor α-blockers, nuclear factor κB inhibitors, antiangioge…
[Coronary artery ectasia: etiopathogenesis, diagnosis and treatment].
2014
Coronary ectasia is a dilation of coronary arteries, angiographically defined if the diameter of the artery is ≥ 1.5 times greater than that of the intact adjacent vascular segment. An association has been found between coronary artery ectasia and a broad spectrum of different diseases, first of all atherosclerotic coronary artery disease. The mechanisms that determine the abnormal dilatation of the vascular lumen and the etiology of coronary artery ectasia are still poorly understood. Various hypotheses have been formulated over the time, the most accredited between these recognizes as main responsible an uncontrolled activity of a particular family of enzymes that degrade the extracellula…
A recurrence-free variant of strassen’s algorithm on hypercube
1995
In this paper a non-recursive Strassen’s matrix multiplication algorithm is presented. This new algorithm is suitable to run on parallel environments. Two computational schemes have been worked out exploiting different parallel approaches on hypercube architecture. A comparative analysis is reported. The experiments have been carried out on an nCUBE-2 supercomputer, housed at CNUCE in Pisa, supporting the Express parallel operating system. © 1995, Taylor & Francis Group, LLC. All rights reserved.
Health monitoring of high performance composite pressure vessels,
2018
International audience; The most important form of damage in carbon fiber reinforced composite pressure vessels is the failure of the fibers however the rate of fiber failure is controlled by the viscoelastic nature of the matrix, which determines overall in-service lifetimes. This type of damage is very different from that encountered with metal pressure vessels and requires a detailed understanding in order to ensure reliability. Innovative proof testing methods based on these processes are necessary. The damage processes and the means of quantifying them are discussed. Their reliability under pressure over periods of decades is analyzed. Intrinsic safety factors linked directly to the pr…
Due Diligence Matrix for Main User Groups of Financial Analysis
2014
Abstract Today the financial analysis indicators of an enterprise are topical for both internal and external users of an enterprise. Unfortunately, often to analyze the financial status of an enterprise and to identify the potential of an enterprise, it is not enough to have customary financial analysis indicators. In this paper, the data of the research that was conducted by the end of the year 2013 has been used. 1935 respondents took part in the survey – representatives of the leading business sectors in Latvia and representatives of the large and medium-sized enterprises. In the research, the authors have applied quantitative and qualitative methods of economics such as the mathematical…
A laser ion source for trace analysis
1988
A laser ion source has been set up which is based on resonant stepwise excitation and ionization of atomic vapor confined in an ionization chamber. Using a pulsed copper vapor/dye laser system with a high repetition rate (6.5 kHz) one expects high efficiency and high selectivity for this new type of ion source. First test experiments with lead are reported.
Production of negative osmium ions by laser desorption and ionization.
2010
The interest to produce negative osmium ions is manifold in the realm of high-accuracy ion trap experiments: high-resolution nearly Doppler-free laser spectroscopy, antihydrogen formation in its ground state, and contributions to neutrino mass spectrometry. Production of these ions is generally accomplished by sputtering an Os sample with Cs(+) ions at tens of keV. Though this is a well-established method commonly used at accelerators, these kind of sources are quite demanding and tricky to operate. Therefore, the development of a more straightforward and cost effective production scheme will be of benefit for ion trap and other experiments. Such a scheme makes use of desorption and ionizat…