Results 41 to 50 of about 36,965 (299)

Reformulating mixed-integer quadratically constrained quadratic programs [PDF]

open access: yes, 2011
It is well known that semidefinite programming (SDP) can be used to derive useful relaxations for a variety of optimisation problems. Moreover, in the particular case of mixed-integer quadratic programs, SDP has been used to reformulate problems, rather ...
Galli, L, Letchford, A. N.
core  

Discordance Between Systemic Lupus Erythematosus Disease Activity Index Domain Weights and Their Association With Organ Damage Accrual

open access: yesArthritis Care &Research, EarlyView.
Objective Studies of damage accrual in patients with systemic lupus erythematosus (SLE) show associations with disease activity measured by the SLE Disease Activity Index 2000 (SLEDAI‐2K), but these associations are imperfect. SLEDAI scores are powerfully influenced by weightings (1–8) assigned to each domain.
Kevin Zhang   +8 more
wiley   +1 more source

Approximation of correlation function and power spectral density with Sonin–Laguerre orthogonal functions

open access: yesVestnik Samarskogo Gosudarstvennogo Tehničeskogo Universiteta. Seriâ: Fiziko-Matematičeskie Nauki, 2008
Approximate capabilities of Sonin–Laguerre orthogonal functions with predefined parameter of orthogonal basis are studied. Parameters of approximation expression are evaluated, that are used for construction of the models of correlation function and ...
I. M. Kulikovskikh, S. A. Prokhorov
doaj   +1 more source

Semidefinite Approximation for Mixed Binary Quadratically Constrained Quadratic Programs [PDF]

open access: yesSIAM Journal on Optimization, 2014
Motivated by applications in wireless communications, this paper develops semidefinite programming (SDP) relaxation techniques for some mixed binary quadratically constrained quadratic programs (MBQCQP) and analyzes their approximation performance. We consider both a minimization and a maximization model of this problem. For the minimization model, the
Zi Xu, Mingyi Hong 0001, Zhi-Quan Luo
openaire   +2 more sources

A Q‐Learning Algorithm to Solve the Two‐Player Zero‐Sum Game Problem for Nonlinear Systems

open access: yesInternational Journal of Adaptive Control and Signal Processing, Volume 39, Issue 3, Page 566-581, March 2025.
A Q‐learning algorithm to solve the two‐player zero‐sum game problem for nonlinear systems. ABSTRACT This paper deals with the two‐player zero‐sum game problem, which is a bounded L2$$ {L}_2 $$‐gain robust control problem. Finding an analytical solution to the complex Hamilton‐Jacobi‐Issacs (HJI) equation is a challenging task.
Afreen Islam   +2 more
wiley   +1 more source

An Accurate Approximation to the Distribution of a Linear Combination of Non-Central Chi-Square Random Variables

open access: yesRevstat Statistical Journal, 2013
This paper provides an accessible methodology for approximating the distribution of a general linear combination of non-central chi-square random variables. Attention is focused on the main application of the results, namely the distribution of positive
Hyung-Tae Ha
doaj   +1 more source

Slowly rotating solution of quadratic gravity: An analytical approximation method

open access: yesNuclear Physics B, 2023
As we know, it is a nontrivial task to obtain analytical solutions for various gravitational theories. In this work, we obtain an analytical approximate rotating black hole solution for quadratic gravity (QG).
S.N. Sajadi, S.H. Hendi
doaj   +1 more source

Revisiting Stability Criteria in Ball‐Milled High‐Entropy Alloys: Do Hume–Rothery and Thermodynamic Rules Equally Apply?

open access: yesAdvanced Engineering Materials, Volume 27, Issue 6, March 2025.
The stability criteria affecting the formation of high‐entropy alloys, particularly focusing in supersaturated solid solutions produced by mechanical alloying, are analyzed. Criteria based on Hume–Rothery rules are distinguished from those derived from thermodynamic relations. The formers are generally applicable to mechanically alloyed samples.
Javier S. Blázquez   +5 more
wiley   +1 more source

Сoordinate functions quadratic approximation in V.I. Slivker's semi-shear stability theory

open access: yesИнженерно-строительный журнал, 2019
Variational formulation of stability problems for thin-walled beams is presented. Geometrical stiffness matrix is derived from the stability functional. Shear deformation is taken into account by using V.I.Slivker’s semi-shear theory of thin-walled bars.
Vladimir Rybakov   +3 more
doaj   +1 more source

Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination

open access: yesGeofluids, 2020
Fluid discrimination plays an important role in reservoir exploration and development. At present, the fluid factors used for fluid discrimination are estimated by linear AVA inversion methods based on the linear approximations of the Zoeppritz equations.
Lin Zhou   +5 more
doaj   +1 more source

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