Optimization Software Guide

Moré, Jorge J.; Wright, Stephen J.

doi:10.1137/1.9781611970951

Cited by 205 publications

(59 citation statements)

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“…This rapidly cooling gas should condense into cold gas clouds and/or form stars on short time-scales relative to the age of the cluster (Fabian 1994). However, the cold gas mass (Braine & Dupraz 1994;McNamara & Jaffe 1994;O'Dea et al 1994;Edge 2001;Salomé & Combes 2003) and star formation rates observed (McNamara & O'Connell 1989) are too low to be consistent with the mass of gas that should be cooling from the ICM.…”

Section: Introductionmentioning

confidence: 99%

Optical emission line nebulae in galaxy cluster cores 1: the morphological, kinematic and spectral properties of the sample

Hamer

Edge

Swinbank

et al. 2016

Mon. Not. R. Astron. Soc.

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We present an Integral Field Unit survey of 73 galaxy clusters and groups with the VIsible Multi Object Spectrograph (VIMOS) on VLT. We exploit the data to determine the Hα gas dynamics on kpc-scales to study the feedback processes occurring within the dense cluster cores. We determine the kinematic state of the ionised gas and show that the majority of systems (∼ 2/3) have relatively ordered velocity fields on kpc scales that are similar to the kinematics of rotating discs and are decoupled from the stellar kinematics of the Brightest Cluster Galaxy. The majority of the Hα flux (> 50 %) is typically associated with these ordered kinematics and most systems show relatively simple morphologies suggesting they have not been disturbed by a recent merger or interaction. Approximately 20 % of the sample (13/73) have disturbed morphologies which can typically be attributed to AGN activity disrupting the gas. Only one system shows any evidence of an interaction with another cluster member. A spectral analysis of the gas suggests that the ionisation of the gas within cluster cores is dominated by non stellar processes, possibly originating from the intracluster medium itself.

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Section: Introductionmentioning

confidence: 99%

Optical emission line nebulae in galaxy cluster cores 1: the morphological, kinematic and spectral properties of the sample

Hamer

Edge

Swinbank

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The agreement between the Gaussian and the deviation from climatology is also quantified by calculating the sum square of the residuals between them (Moré and Wright, 1993). It is evident in Fig.…”

Section: Resultsmentioning

confidence: 98%

Continuous detection and characterization of the Sea Breeze in clear sky conditions using Meteosat Second Generation

Lensky

Dayan

2012

Atmos. Chem. Phys.

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Abstract. The sea breeze (SB) is a thermally induced boundary layer phenomenon that occurs at coastal locations throughout the world. Previous satellite remote sensing studies used low-level clouds formed over the sea-breeze convergence zones to identify the SB. In this study continuous thermal infrared data from a geostationary satellite (Meteosat Second Generation) and concurrent field measurements were used to detect and characterize the SB in clear sky conditions during the summer. Surface data (wind speed and direction) from 11 sites over Israel for ten summer days in July 2010 for three different synoptic circulation categories were selected.In order to assess the impact of the synoptic induced flow on the SB, we looked for the best agreement between surface and satellite SB timing. An independent classification of synoptic categories performed for the ten summer days revealed two distinct patterns of the SB. During weak horizontal pressure gradient (Weak Persian Trough and High to the West), which enables full development of the SB, the timing of the SB from satellite and field measurements were well correlated (R 2 = 0.75), as compared to unfavorable atmospheric conditions (Deep Persian Trough) yielding lower value (R 2 = 0.5). The SB was identified by surface measurements in an earlier time of the day, with respect to the satellite column integrated measurements.Visualizing timing of the SB retrieved from satellite data enabled distinction of SB behavior under different synoptic categories. Over desert regions the strong thermal contrast enables detection of the SB even under suppressing synoptic conditions (Deep Persian Trough).This method enables detection and timing of the SB over desert regions where clouds and field measurements are scarce, and is applicable worldwide.

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“…For a guide to software for numerical U 1586 Unconstrained Optimization optimization, see Moré and Wright (1993) and the online NEOS Optimization Software Guide. This article focused on methods for computing local optima of differentiable functions; for a survey of methods for optimizing nondifferentiable functions, see Lemarechal (1989), and for a survey of derivative-free methods, see Kolda, Lewis and Torczon (2003).…”

Section: Discussionmentioning

confidence: 99%

Unary NP-Complete (NP-Hard)

2013

Encyclopedia of Operations Research and Management Science

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A transportation problem in which the total amount to be shipped (supply) is not equal to the total demand. The unbalanced problem can be stated as a standard transportation problem by the addition of a fictitious destination when the supply is greater than the demand, or by adding a fictitious origin if the demand is greater than the supply. In the first case, the demand at the fictitious destination is the difference between the total supply and total demand, while in the second case, the supply at the fictitious origin is the difference between the total demand and total supply. See ▶ Transportation Problem Unbounded Optimal SolutionA solution to a constrained optimization problem in which the objective function value can be shown to increase (or decrease) without bound on the feasible region. A real-world problem whose mathematical model exhibits an unbounded optimal solution must have an incorrect formulation. Unconstrained OptimizationAriela Sofer George Mason University, Fairfax, VA, USA IntroductionUnconstrained optimization is concerned with finding the minimizing or maximizing points of a nonlinear function, where the variables are free to take on any value. Unconstrained optimization problems occur in a wide range of applications in science and engineering. A rich source of unconstrained optimization problems are data-fitting problems, in which some model function with unknown parameters is fitted to data, using some criterion of best fit. This criterion may be the minimum sum of squared errors, or the maximum of a likelihood or entropy function. Unconstrained problems also arise from constrained optimization problems, since these are often solved by solving a sequence of unconstrained problems.In mathematical terms, an unconstrained minimization problem can be written in the form minimize f ðxÞ; where x ¼ ðx 1 ; . . . ; x n Þ T is a vector of unrestricted variables in the n-dimensional space < n . Ideally, one would like to find a global minimizer of the function, i.e., a point x Ã that yields the lowest value of f. Such a solution satisfies If the inequality above holds strictly, i.e., f ðx Ã Þ < f ðxÞ for all x, then x Ã is a strict global minimizer.In many cases, finding a global minimizer is extremely difficult. For this reason, most algorithms attempt only to find a local minimizer of the function, i.e., a point x Ã that satisfies f ðx Ã Þ f ðxÞ for all x in some neighborhood of x Ã . If the objective f is a convex function (see the next section), a local minimizer will also be a global minimizer; however, for nonconvex functions this property does not generally hold.There is no inherent difference between minimization problems and maximization problems, since maximizing f can be accomplished by minimizing À f and then multiplying the optimal objective values by À 1. For this reason it is sufficient to focus only on unconstrained minimization problems. BackgroundMuch of the research in unconstrained optimization has focused on functions with continuous derivatives. Throughout this discussion it ...

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Optimization Software Guide

Cited by 205 publications

References 0 publications

Optical emission line nebulae in galaxy cluster cores 1: the morphological, kinematic and spectral properties of the sample

Optical emission line nebulae in galaxy cluster cores 1: the morphological, kinematic and spectral properties of the sample

Continuous detection and characterization of the Sea Breeze in clear sky conditions using Meteosat Second Generation

Unary NP-Complete (NP-Hard)

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