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University of Richmond

Series

1996

Articles 1 - 8 of 8

Full-Text Articles in Physical Sciences and Mathematics

An Inverse Problem In Thermal Imaging, Kurt Bryan, Lester Caudill Jun 1996

An Inverse Problem In Thermal Imaging, Kurt Bryan, Lester Caudill

Department of Math & Statistics Faculty Publications

This paper examines uniqueness and stability results for an inverse problem in thermal imaging. The goal is to identify an unknown boundary of an object by applying a heat flux and measuring the induced temperature on the boundary of the sample. The problem is studied in both the case in which one has data at every point on the boundary of the region and the case in which only finitely many measurements are available. An inversion procedure is developed and used to study the stability of the inverse problem for various experimental configurations.

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On Quaternionic Pseudo-Random Number Generators, Gary R. Greenfield May 1996

On Quaternionic Pseudo-Random Number Generators, Gary R. Greenfield

Department of Math & Statistics Technical Report Series

There is no dearth of published literature on the design, implementation, analysis, or use of pseudo-random number generators or PRNGs. For example, [6] [7] [14] and the references therein, provide a broad overview and firm grounding for the subject. This report complements and elaborates upon the work of McKeever [9], who investigated PRNGs constructed in a non-commutative setting with the target application being so-called cryptographically secure PRNGs as discussed in [12] or [13]. Novel "solutions" to the problem of designing cryptographically secure PRNGS continue to be proposed [1] [2] [10] [15], so despite the caution and skepticism required, the area …

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Invariant Subspaces Of The Harmonic Dirichlet Space With Large Co-Dimension, William T. Ross Jan 1996

Invariant Subspaces Of The Harmonic Dirichlet Space With Large Co-Dimension, William T. Ross

Department of Math & Statistics Faculty Publications

In this paper, we comment on the complexity of the invariant subspaces (under the bilateral Dirichlet shift f → ζf) of the harmonic Dirichlet space D. Using the sampling theory of Seip and some work on invariant subspaces of Bergman spaces, we will give examples of invariant subspaces F ⊂ D with dim(F/ζF) = n, n ∈ N ∪ {∞}. We will also generalize this to the Dirichlet classes Dα, 0 <α< ∞, as well as the Besov classes Bα p , 1

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Bergman Spaces On Disconnected Domains, William T. Ross, Alexandru Aleman, Stefan Richter Jan 1996

Bergman Spaces On Disconnected Domains, William T. Ross, Alexandru Aleman, Stefan Richter

Department of Math & Statistics Faculty Publications

For a bounded region G C C and a compact set K C G, with area measure zero, we will characterize the invariant subspaces M (under f -> zf)of the Bergman space Lpa(G \ K), 1 ≤ p < ∞, which contain Lpa(G) and with dim(M/(z - λ)M) = 1 for all λϵ G \ K. When G \ K is connected, we will see that di\m(M /(z — λ)M) = 1 for all λ ϵ G \ K and thus in this case we will have a complete …

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The Backward Shift Of Weighted Bergman Spaces, William T. Ross, Alexandru Aleman Jan 1996

The Backward Shift Of Weighted Bergman Spaces, William T. Ross, Alexandru Aleman

Department of Math & Statistics Faculty Publications

No abstract provided.

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Exponent Bounds For A Family Of Abelian Difference Sets, K. T. Arasu, James A. Davis, Jonathan Jedwab, Siu Lun Ma, Robert L. Mcfarland Jan 1996

Exponent Bounds For A Family Of Abelian Difference Sets, K. T. Arasu, James A. Davis, Jonathan Jedwab, Siu Lun Ma, Robert L. Mcfarland

Department of Math & Statistics Faculty Publications

Which groups G contain difference sets with the parameters (v, k, λ)= (q3 + 2q2 , q2 + q, q), where q is a power of a prime p? Constructions of K. Takeuchi, R.L. McFarland, and J.F. Dillon together yield difference sets with these parameters if G contains an elementary abelian group of order q2 in its center. A result of R.J. Turyn implies that if G is abelian and p is self-conjugate modulo the exponent of G, then a necessary condition for existence is that the exponent …

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A Survey Of Hadamard Difference Sets, James A. Davis, Jonathan Jedwab Jan 1996

A Survey Of Hadamard Difference Sets, James A. Davis, Jonathan Jedwab

Department of Math & Statistics Faculty Publications

A (v, k, λ) difference set is a k-element subset D of a group G of order v for which the multiset {d1d2-1 : d1, d2 ∈ D, d1 ≠ d2} contains each nonidentity element of G exactly λ times. A difference set is called abelian, nonabelian or cyclic according to the properties of the underlying group. Difference sets are important in design theory because they are equivalent to symmetric (v, k, λ) designs with a regular automorphism group [L].

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Detecting Trends And Patterns In Reliability Data Over Time Using Exponentially Weighted Moving-Averages, Harry F. Martz, Paul H. Kvam Jan 1996

Detecting Trends And Patterns In Reliability Data Over Time Using Exponentially Weighted Moving-Averages, Harry F. Martz, Paul H. Kvam

Department of Math & Statistics Faculty Publications

A simple, easy-to-use graphical method is presented for use in determining if there is any statistically significant trend or pattern over time in an underlying Poisson event rate of occurrence or binomial failure on demand probability. The method is based on the combined use of both an exponentially weighted moving-average (EWMA) and a Shewhart chart. Two nuclear power plant examples are introduced and used to illustrate the method. The false alarm probability and power when using the combined procedure are also determined for both cases using Monte Carlo simulation. The results indicate that the combined procedure is quite effective in …

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