Results 81 to 90 of about 878,195 (332)

On Positive Semidefinite Matrices with Known Null Space [PDF]

SIAM Journal on Matrix Analysis and Applications, 2002
We show how the zero structure of a basis of the null space of a positive semidefinite matrix can be exploited to determine a positive definite submatrix of maximal rank. We discuss consequences of this result for the solution of (constrained) linear systems and eigenvalue problems.
Arbenz, Peter, Drmac, Zlatko
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A Robust Adaptive One‐Sample‐Ahead Preview Super‐Twisting Sliding Mode Controller

International Journal of Adaptive Control and Signal Processing, EarlyView.
Block Diagram of the Robust Adaptive One‐Sample‐Ahead Preview Super‐Twisting Sliding Mode Controller. ABSTRACT This article introduces a discrete‐time robust adaptive one‐sample‐ahead preview super‐twisting sliding mode controller. A stability analysis of the controller by Lyapunov criteria is developed to demonstrate its robustness in handling both ...
Guilherme Vieira Hollweg, Paulo Jefferson Dias de Oliveira Evald, Shivam Chaturvedi, Hilton Abilio Gründling, Rodrigo Varella Tambara, Wencong Su   +5 more
wiley   +1 more source

A Matrix Model for the Null-Brane

, 2005
The null-brane background is a simple smooth 1/2 BPS solution of string theory. By tuning a parameter, this background develops a big crunch/big bang type singularity.
A. Bergman, A. Hashimoto, A. Lawrence, B. Chen, B. Craps, B. Craps, B. Durin, B. Pioline, B.L. Cerchiai, D. Robbins, D. Robbins, D.W. Chiou, Daniel Robbins, E.J. Martinec, H. Liu, H. Liu, J. Figueroa-O'Farrill, J. Gomis, J. McGreevy, J. Simon, J. Simon, J.-H. She, J.L. Hovdebo, J.R. David, K. Dasgupta, K. Dasgupta, K. Okuyama, L. Fidkowski, L. Motl, L. Motl, M. Alishahiha, M. Berkooz, M. Berkooz, M. Berkooz, M. Berkooz, M. Fabinger, M. Fabinger, M. Li, O.J. Ganor, S. Elitzur, S. Kawai, Savdeep Sethi, T. Hertog, T. Hertog, T. Ishino, V.E. Hubeny, Y. Hikida, Y. Hikida   +47 more
core   +2 more sources

Enhancing Corrosion Resistance and Mechanical Strength of 3D‐Printed Iron Polylactic Acid for Marine Applications via Laser Surface Texturing

Advanced Engineering Materials, EarlyView.
Laser surface texturing significantly improves the corrosion resistance and mechanical strength of 3D‐printed iron polylactic acid (Ir‐PLA) for marine applications. Optimal laser parameters reduce corrosion by 80% and enhance tensile strength by 25% and ductility by 15%.
Mohammad Rezayat, Mojtaba Karamimoghadam, Mohammadreza Lalegani Dezaki, Ali Zolfagharian, Giuseppe Casalino, Antonio Mateo, Mahdi Bodaghi   +6 more
wiley   +1 more source

Null Cones in Lorentz-Covariant General Relativity [PDF]

, 2001
The oft-neglected issue of the causal structure in the flat spacetime approach to Einstein's theory of gravity is considered. Consistency requires that the flat metric's null cone be respected, but this does not happen automatically.
Pitts, J. Brian, Schieve, W. C.
core   +1 more source

Characterization of Defect Distribution in an Additively Manufactured AlSi10Mg as a Function of Processing Parameters and Correlations with Extreme Value Statistics

Advanced Engineering Materials, EarlyView.
Predicting extreme defects in additive manufacturing remains a key challenge limiting its structural reliability. This study proposes a statistical framework that integrates Extreme Value Theory with advanced process indicators to explore defect–process relationships and improve the estimation of critical defect sizes. The approach provides a basis for
Muhammad Muteeb Butt, Varma Kvvssn, Hossein Laieghi, Zia Uddin, Peyman Ansari, E. Kıvanç Sadak, Can Barış Toprak, Hüseyin Kızıl, Enrico Salvati   +8 more
wiley   +1 more source

Integrable system of null curve and Betchov-Da Rios equation

Demonstratio Mathematica
This study focuses on the time evolution of a null curve using a new frame and a new transformation in Minkowski 3-space. Accordingly, Landau–Lifshitz and coupled Boussinesq-like equations for the null curve are provided in terms of the new ...
Yoon Dae Won
doaj   +1 more source

Damage Detection in Beam Bridges Using Quasi-static Displacement Influence Lines

Applied Sciences, 2019
Quasi-static strain influence lines (ILs) based on the Brillouin optical time domain analysis (BOTDA) technique have been proposed to effectively locate damage in beam bridges.
Shaoyi Zhang, Yang Liu
doaj   +1 more source

CR Structures and Asymptotically Flat Space-Times

, 2005
We discuss the unique existence, arising by analogy to that in algebraically special space-times, of a CR structure realized on null infinity for any asymptotically flat Einstein or Einstein-Maxwell space-time.Comment: 6 ...
Ezra T Newman, Goldberg J N, Hansen R, Kozameh C, Kozameh C, Kozameh C, Lewandowski J, Lewandowski J, Lewandowski J, Newman E T, Newman E T, Pawel Nurowski, Penrose R, Penrose R, Penrose R, Robinson I   +15 more
core   +1 more source

THE CESARO SPACE OF NULL SEQUENCES

Communications, Faculty Of Science, University of Ankara Series A1Mathematics and Statistics, 1986
Let \(\sigma (c_ 0)\) denote the Cesàro space of null sequences. Let \(c_ 0\) denote the space of the null sequences. First, necessary and sufficient conditions for an FK-space to include \(\sigma (c_ 0)\) are given. One set of conditions involve the Hahn sequence space, h [\textit{G. Goes} and \textit{S. Goes}: Math. Z. 118, 93-102 (1970; Zbl 0198.404)
openaire   +3 more sources