We present some reÐnements of a recently developed scheme for interpolating and iteratively improving molecular potentialenergy surfaces (PES). By comparison with an analytic surface for the reaction, we show that an accurate OH ] 2 H2O] H and smooth PES may be constructed using of the order of 100È200 calculations of the energy, energy gradient and second derivatives. The reÐnements rely, in p...

Subspace learning and matrix factorization problems have a great many applications in science and engineering, and efficient algorithms are critical as dataset sizes continue to grow. Many relevant problem formulations are non-convex, and in a variety of contexts it has been observed that solving the non-convex problem directly is not only efficient but reliably accurate. We discuss convergence...

Given a Hilbert space (H, 〈·, ·〉), and interval Λ ⊂ (0, +∞) and a map K ∈ C(H,R) whose gradient is a compact mapping, we consider the family of functionals of the type: I(λ, u) = 1 2 〈u, u〉 − λK(u), (λ, u) ∈ Λ×H. As already observed by many authors, for the functionals we are dealing with the (PS) condition may fail under just this assumptions. Nevertheless, by using a recent deformation Lemma ...

This paper presents a gradient-based parameter optimization method to find the optimal compensator that minimizes the standard deviation ( PES) of the position error signal (PES) in a hard disk drive servo system. By using the plant response data and the PES gradient information based on the nominal plant model, optimal digital controllers that minimized the 3 PES of a plant with uncertainty we...

[1] Boreal streams represent potentially important conduits for the exchange of carbon dioxide (CO2) between terrestrial ecosystems and the atmosphere. The gas transfer coefficient of CO2 (KCO2) is a key variable in estimating this source strength, but the scarcity of measured values in lotic systems creates a risk of incorrect flux estimates even when stream gas concentrations are well known. ...

We propose a Bayesian approach for recursively estimating the classifier weights in online learning of a classifier ensemble. In contrast with past methods, such as stochastic gradient descent or online boosting, our approach estimates the weights by recursively updating its posterior distribution. For a specified class of loss functions, we show that it is possible to formulate a suitably defi...

Large-eddy simulations are performed to analyze film cooling in supersonic combustion ramjets (Scramjets). The transonic film cooling flow is injected through a slot parallel to a Ma = 2.44 main stream with a fully turbulent boundary layer. The injection Mach number is Mai = 1.2 and adiabatic wall conditions are imposed. The cooling effectiveness is investigated for adverse and favorable pressu...

Global warming is widely predicted to reduce the biomass production of top predators, or even result in species loss. Several exceptions to this expectation have been identified, however, and it is vital that we understand the underlying mechanisms if we are to improve our ability to predict future trends. Here, we used a natural warming experiment in Iceland and quantitative theoretical predic...

Watershed land use in suburban areas can affect stream biota through degradation of instream habitat, water quality, and riparian vegetation. By monitoring stream biotic communities in various geographic regions, we can better understand and conserve our watershed ecosystems. The objective of this study was to examine the relationship between watershed land use and the integrity of benthic inve...