From an empirical point of view, the hardness of quantified Boolean formulas (QBFs), can be characterized by the (in)ability of current state-of-the-art QBF solvers to decide about the truth of formulas given limited computational resources. In this paper, we start from the problem of computing empirical hardness markers, i.e., features that can discriminate between hard and easy QBFs, and we e...

Realistic prediction of concrete shrinkage and creep requires the calculation of the distributions of relative humidity at various times. Although the distributions of the relative humidity can be computed by numerical methods from the differential equation for diffusion, simple prediction formulas can facilitate structural analysis. The purpose of this paper is to present a simple formula for ...

Traditional algorithms for prime implicate generation [Quine, 1952; McCluskey, 1956; Tison, 1967; Kean and Tsiknis, 1990; de Kleer, 1992] require the input formulas to be first transformed into a CNF formula. This process, however, requires exponential time in the worst case and can result in an exponential blow up of the input size. Such cases occur frequently when the problem domains are best...

According to a result of S. N. Bernstein, «-point Chebyshev quadrature formulas, with all nodes real, do not exist when n = 8 or n ä 10. Modifications of such quadrature formulas have recently been suggested by R. E. Barnhill, J. E. Dennis, Jr. and G. M. Nielson, and by D. Kahaner. We establish here certain empirical observations made by these authors, notably the presence of multiple nodes. We...

The production of spallation residues in 56Fe+p bombardments is described with empirical parametric formulas often used cosmic-ray astrophysics, activation studies and isotope for medical applications. Experimental observables including mass, charge isotopic distributions are compared calculations using two versions the Rudstam Silberberg-Tsao SPACS formula. For reference, a comparison made pre...

This paper characterizes the welfare gains from government intervention when the private sector provides partial insurance. We analyze models in which adverse selection, preexisting information, or imperfect optimization in private insurance markets create a role for government intervention. We derive simple formulas that map existing empirical estimates into quantitative predictions for optima...

A large data set on ripples was collected and examined. A set of new formulas for the prediction of the ripple characteristics is proposed with an emphasis on the disappearance of the ripples. The ripple wavelength was observed to be proportional to the bottom wave excursion but also to be a function of the grain-related Shields parameter and wave period parameter introduced by Mogridge et al. ...

The empirical saddlepoint distribution provides an approximation to the sampling distributions for the GMM parameter estimates and the statistics that test the overidentifying restrictions. The empirical saddlepoint distribution permits asymmetry, non-normal tails, and multiple modes. If identification assumptions are satisfied, the empirical saddlepoint distribution converges to the familiar a...

The empirical saddlepoint distribution provides an approximation to the sampling distributions for the GMM parameter estimates and the statistics that test the overidentifying restrictions. The empirical saddlepoint distribution permits asymmetry, non-normal tails, and multiple modes. If identification assumptions are satisfied as the sample size grows the empirical saddlepoint distributions co...