A New Statistical Parser Based on Bigram Lexical Dependencies

This paper describes a new statistical parser which is based on probabilities of dependencies between head-words in the parse tree. Standard bigram probability estimation techniques are extended to calculate probabilities of dependencies between pairs of words. Tests using Wall Street Journal data show that the method performs at least as well as SPATTER (Magerman 95, Jelinek et al 94), which has the best published results for a statistical parser on this task. The simplicity of the approach means the model trains on 40,000 sentences in under 15 minutes. With a beam search strategy parsing speed can be improved to over 200 sentences a minute with negligible loss in accuracy.Comment: 8 pages, to appear in Proceedings of ACL 96. Uuencoded gz-compressed postscript file created by csh script uufile

Three Generative, Lexicalised Models for Statistical Parsing

In this paper we first propose a new statistical parsing model, which is a generative model of lexicalised context-free grammar. We then extend the model to include a probabilistic treatment of both subcategorisation and wh-movement. Results on Wall Street Journal text show that the parser performs at 88.1/87.5% constituent precision/recall, an average improvement of 2.3% over (Collins 96).Comment: 8 pages, to appear in Proceedings of ACL/EACL 97

Ab initio lattice dynamics of nonconducting crystals by systematic fragmentation

A systematic method for approximating the ab initio electronic energy of crystal lattices has been improved by the incorporation of long range electrostatic and dispersion interactions. The effect of these long range interactions on the optimization of the crystal structure is reported. The harmonic lattice dynamics have been evaluated to give phonon frequencies and neutron scattering intensities. Exemplary results are reported for diamond, silicon, and α-quartz using Hartree-Fock, Möller-Plesset perturbation, and coupled-cluster levels of ab initio theory

Molecular potential energy surfaces constructed from interpolation of systematic fragment surfaces

A systematic method for approximating the ab initio electronic energy of molecules from the energies of molecular fragments has previously been presented. Here it is shown that this approach provides a feasible, systematic method for constructing a global molecular potential energy surface (PES) for reactions of a moderate-sized molecule from the corresponding surfaces for small molecular fragments. The method is demonstrated by construction of PESs for the reactions of a hydrogen atom with propane and n-pentane

\u3cem\u3eWillson v. Black-Bird Creek Marsh Co.\u3c/em\u3e, 25 U.S. 245 (1829): An Early Test of the Dormant Commerce Clause

In 1822, Delaware authorized the Blackbird Creek Marsh Company to bank and drain the Blackbird Creek in New Castle County. Subsequently, Thompson Wilson and others destroyed the structure built by the marsh company. The marsh company subsequently sued Mr. Wilson for the damage to its property. The parties eventually appealed their dispute to the Supreme Court of the United States. The Court held that Delaware’s authorization to bank and dam the creek did not conflict with the federal government’s exclusive authority to regulate commerce between the several states. Ultimately, the Court decided Willson in a manner inconsistent with its earlier decision in Gibbons v. Ogden and subsequent decisions regarding navigation of U.S. waters. Additionally, Mr. Wilson likely chose not to bring a Fifth Amendment takings claim due to the lack of legal support for such a claim at the time

Measuring the Delivery Costs of Prepurchase Homeownership Education and Counseling

In order to understand the roles that public policy and the business and consumer sectors play in paying for homeownership education and counseling, the costs, benefits and beneficiaries of the education and training must be fully accounted for. This paper estimates the total costs of delivering homeownership education and counseling and discusses proven and implied benefits to stakeholders. Based on one set of assumptions, and depending on the level of activities offered, homeownership education and counseling costs range from $500 to$1,500. Empirical and anecdotal evidence suggest that homeownership education and counseling offer important benefits to borrowers, lenders, real estate professionals and communities. Many nonprofit organizations providing such services, however, remain underfunded. Providers, financial institutions and policy makers must increase their knowledge of what works, what costs are incurred, who benefits, and what value is created by homeownership education and counseling activities in order to develop a sustainable delivery system.This paper uses information from NeighborWorks organizations that offer homeownership education and counseling programs as illustration of the cost structure of the homeownership education and counseling industry. Part 2 provides background information on the homeownership education and counseling industry. Part 3 explains the methodology and assumptions used for this analysis. Part 4 reviews cost accounting and presents a framework for the cost analysis. Part 5 discusses the value proposition for homeownership education and counseling while Part 6 offers conclusions and implications