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A common question asked by users of direct search algorithms is how to use derivative information at iterates where it is available. This paper addresses that question with respect to Generalized Pattern Search (GPS) methods for unconstrained and linearly constrained optimization. Specifically this paper concentrates on the GPS poll step. Polling is done to(More)
A previous analysis of second-order behavior of generalized pattern search algorithms for unconstrained and linearly constrained minimization is extended to the more general class of mesh adaptive direct search (MADS) algorithms for general constrained optimization. Because of the ability of MADS to generate an asymptotically dense set of search directions,(More)
This paper describes the optimization of a load-bearing thermal insulation system characterized by hot and cold surfaces with a series of heat intercepts and insulators between them. The optimization problem is represented as a mixed variable programming (MVP) problem with nonlinear constraints, in which the objective is to minimize the power required to(More)
In previous work, the generalized pattern search (GPS) algorithm for linearly constrained (continuous) optimization was extended to mixed variable problems, in which some of the variables may be categorical. In another paper, the mesh adaptive direct search (MADS) algorithm was introduced as a generalization of GPS for problems with general nonlinear(More)
OBJECTIVE To determine the attributable hospital stay and costs for nosocomial methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) primary bloodstream infections (BSIs). DESIGN Pairwise-matched (1:1) nested case-control study. SETTING University-based tertiary-care medical center. PATIENTS Patients admitted(More)
The purpose of this paper is to introduce a new way of choosing directions for the Mesh Adaptive Direct Search (MADS) class of algorithms. The advantages of this new ORTHOMADS instantiation of MADS are that the polling directions are chosen deterministically, ensuring that the results of a given run are repeatable, and that they are orthogonal to each(More)
Previous analyses of pattern search algorithms for unconstrained and linearly constrained minimization have focused on proving convergence of a subsequence of iterates to a limit point satisfying either directional or first-order necessary conditions for optimality, depending on the smoothness of the objective function in a neighborhood of the limit point.(More)
BACKGROUND Although transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) in detecting echocardiographic evidence of infective endocarditis (IE), the impact of TEE on the clinical diagnosis of IE has not been clearly delineated. METHODS AND RESULTS We studied 112 patients with 114 suspected episodes of IE over(More)
BACKGROUND The epidemiology, criteria for diagnosis and treatment of bacterial endocarditis has changed substantially in the past 2 decades, yet little attention has been given to the changing etiologies of renal insufficiency and the predictors of renal failure or the relationship between renal failure and mortality in patients with bacterial endocarditis.(More)