Physical Sciences and Mathematics Commons^™

The Spectral Center Of Gravity Effect And Auditory Filter Bandwidth, Marc Fagelson, Linda M. Thibodeau

Marc A. Fagelson

Mccolm’S Conjecture, Yuri Gurevich, Neil Immerman, Saharon Shelah

Neil Immerman

Gregory McColm conjectured that positive elementary inductions are bounded in a class K of finite structures if every (FO + LFP) formula is equivalent to a first-order formula in K. Here (FO + LFP) is the extension of first-order logic with the least fixed point operator. We disprove the conjecture. Our main results are two model-theoretic constructions, one deterministic and the other randomized, each of which refutes McColm’s conjecture.

Evidence For A Disk In The Wind Of Hd 93521: Uv Line Profiles From An Axisymmetric Model., Richard Ignace

Richard Ignace

Recently it has been suggested (Massa 1992; Howarth & Reid 1993), from the C IV ultraviolet resonance line profile of HD 93521, that there is a high-speed component in the polar outflow from the star as well as a low-speed component in the equatorial regions. In this paper we present theoretical calculations of the line profiles that would be produced by such a model. We find from Hubble Space Telescope (HST) Goddard High Resolution Spectrograph (GHRS) observations of HD 93521 that the observed C IV profile can be produced if the star has an inclination angle very close to 90 …

Application Of The Binomial Index Of Model Fit: What Research Question Is Being Investigated?, Isadore Newman, John Fraas, Timothy Norfolk

John W. Fraas

No abstract provided.

X-Ray Studies Of Bond-Orientational Order In Liquid-Crystalline Orthogonal Hexatic-B Phase, E. Gorecka, Li Chen, Oleg Lavrentovich, W. Pyzuk

Oleg Lavrentovich

X-ray scattering measurements have been carried out for free-standing, thick . monodomain films of the orthogonal hexatic-B phase. From Fourier analysis of X-scans, 6n-fold-symmetry order parameters were determined and proved to fulfill the scaling relation C6n = C6n+lambdan(n-1). The temperature behavior of C6 and lambda was found nonuniversal when comparing homologues, PIR5 and PIR7, differing in their range of the hexatic phase. The hexatic order parameter varies with the critical exponents 0.25, 0.20 (+/- 0.03), respectively. For comparison results for compound RFL6, of other homologue series, are presented.

On A Learnability Question Associated To Neural Networks With Continuous Activations, Bhaskar Dasgupta, Hava Siegelmann, Eduardo Sontag

Hava Siegelmann

This paper deals with learnability of concept classes defined by neural networks, showing the hardness of PAC-learning (in the complexity, not merely information-theoretic sense) for networks with a particular class of activation. The obstruction lies not with the VC dimension, which is known to grow slowly; instead, the result follows the fact that the loading problem is NP-complete. (The complexity scales badly with input dimension; the loading problem is polynomial-time if the input dimension is constant). Similar and well-known theorems had already been proved by Megiddo and by Blum and Rivest, for binary-threshold networks. It turns out the general problem …

Why Magnification Works, Terry L. Smith, Jay S. Huebner

Jay S Huebner

The simplest way to magnify the view of a small object is to bring the object closer to the eye, and of course science teachers know about magnifying glasses, telescopes, and microscopes.But why magnification works seems intuitive and is not usually explained to our students. We present here a few ideas on magnification that we use in our classroom and some general information on vision that we hope will be helpful to other teachers.

Biaxiality In A Cyclic Thermotropic Nematic Liquid-Crystal, Jian-Feng Li, V. Percec, Ch. Rosenblatt, Oleg Lavrentovich

Oleg Lavrentovich

Birefringence and textural data are presented for a ring-shaped trimeric liquid crystal. The material apparently undergoes a uniaxial-to-biaxial nematic phase transition as a function of temperature.

Derivation Of A Scaled Binomial As An Instance Of A General Discrete Exponential Distribution, Joseph Hilbe

Joseph M Hilbe

No abstract provided.

Click‐Evoked Otoacoustic Emissions In Normal‐Hearing Children, Jacek Smurzynski

Jacek Smurzynski

A Note On The Real Symmetric Eigenvalue, William F. Trench

William F. Trench

No abstract provided.

A Bayesian Approach To Additive Nonparametric Regression, Michael S. Smith, Robert Kohn

Michael Stanley Smith

This proceedings paper was the first to suggest using a Gaussian g-prior combined with a point mass to undertake Bayesian variable selection in a Gaussian linear regression model. It also was the first to suggest integrating out the regression parameters and variance in closed form, resulting in an efficient Gibbs sampling scheme. The idea was applied to estimate regression functions in an additive model by using a linear basis expansion for each component function in an additive model. The conference proceeding was eventually published in a slightly tighter form in Journal of Econometrics (1996).

Determination Of Plasma Parameters In A Dc Arcjet Diamond Reactor: Part 1, Scott Reeve, Wayne Weimer

Scott Reeve

No abstract provided.

The Variable Elision Of Unstressed Vowels In European Portuguese: A Case Study, David James Silva

David Silva