Explanation-based generalization is used to extract a specialized grammar from the original one using a training corpus of parse trees. This allows very much faster parsing and gives a lower error rate, at the price of a small loss in coverage. Previously, it has been necessary to specify the tree-cutting criteria (or operationality criteria) manually; here they are derived automatically from t...

Problems in operations research are often NP complete and optimal solution for larger problems cannot be obtained, therefore heuristic methods have to be used. The boundary between the size of the problem that can be solved optimally and those where heuristic methods should be used is not always clear. To solve this problem we propose a method based on decision trees. The method can be also use...

We study a fragmentation of the p-trees of Camarri and Pitman [Elect. J. Probab., vol. 5, pp. 1–18, 2000]. We give exact correspondences between the p-trees and trees which encode the fragmentation. We then use these results to study the fragmentation of the ICRTs (scaling limits of p-trees) and give distributional correspondences between the ICRT and the tree encoding the fragmentation. The th...

Partial cutting in bottomland hardwoods to control stand density and species composition sometimes results in logging damage to the lower bole and/or roots of residual trees. If severe, logging damage may lead to a decline in tree vigor, which may subsequently stimulate the production of epicormic branches, causing a decrease in bole quality and an eventual loss in value of the stand. To invest...

Composition and structure of a three-storied Fagus orientalis-dominated forest was investigated in the Caspian forests, north of Iran. Circular sampling plots of 1000 m2 occupied by advance growth and natural regeneration were randomly chosen where the initial cuttings (with shelterwood aim) were performed. Abundance of species at different growth stages and quality of seedlings and saplings we...

Lianas are an important component of tropical forests, where they reduce tree growth, fecundity, and survival. Competition for light from lianas may be intense; however, the amount of light that lianas intercept is poorly understood. We used a large-scale liana-removal experiment to quantify light interception by lianas in a Panamanian secondary forest. We measured the change in plant area inde...

We provide simplified proofs for the asymptotic distribution of the number of cuts required to cut down a Galton–Watson tree with critical, finite-variance offspring distribution, conditioned to have total progeny n. Our proof is based on a coupling which yields a precise, non-asymptotic distributional result for the case of uniformly random rooted labeled trees (or, equivalently, Poisson Galto...