[Rezension zu:] Stefan Ehrenpreis, Ute Lotz-Heumann, Olaf Mörke, Luise Schorn-Schütte, eds. Wege der Neuzeit: Festschrift für Heinz Schilling zum 65. Geburtstag. Historische Forschungen. Berlin: Duncker& Humblot, 2007. 656 pp. EUR 78.00 (paper), ISBN 978-3-428-12394-0.

Rezension zu: Stefan Ehrenpreis, Ute Lotz-Heumann, Olaf Mörke, Luise Schorn-Schütte, eds. Wege der Neuzeit: Festschrift für Heinz Schilling zum 65. Geburtstag. Historische Forschungen. Berlin: Duncker & Humblot, 2007. 656 pp. EUR 78.00 (paper), ISBN 978-3-428-12394-0

Unbounded-Error Classical and Quantum Communication Complexity

Since the seminal work of Paturi and Simon \cite[FOCS'84 & JCSS'86]{PS86}, the unbounded-error classical communication complexity of a Boolean function has been studied based on the arrangement of points and hyperplanes. Recently, \cite[ICALP'07]{INRY07} found that the unbounded-error {\em quantum} communication complexity in the {\em one-way communication} model can also be investigated using the arrangement, and showed that it is exactly (without a difference of even one qubit) half of the classical one-way communication complexity. In this paper, we extend the arrangement argument to the {\em two-way} and {\em simultaneous message passing} (SMP) models. As a result, we show similarly tight bounds of the unbounded-error two-way/one-way/SMP quantum/classical communication complexities for {\em any} partial/total Boolean function, implying that all of them are equivalent up to a multiplicative constant of four. Moreover, the arrangement argument is also used to show that the gap between {\em weakly} unbounded-error quantum and classical communication complexities is at most a factor of three.Comment: 11 pages. To appear at Proc. ISAAC 200

A polynomial chaos approach to stochastic variational inequalities

We consider stochastic elliptic variational inequalities of the second kind involving a bilinear form with stochastic diffusion coefficient. We prove existence and uniqueness of weak solutions, propose a stochastic Galerkin approximation of an equivalent parametric reformulation, and show equivalence to a related collocation method. Numerical experiments illustrate the efficiency of our approach and suggest similar error estimates as for linear elliptic problems

Comparison of Bond in Roll-bonded and Adhesively Bonded Aluminums

Lap-shear and peel test measurements of bond strength have been carried out as part of an investigation of roll bonding of 2024 and 7075 aluminum alloys. Shear strengths of the bonded material in the F temper are in the range of 14 to 16 ksi. Corresponding peel strengths are 120 to 130 lb/inch. These values, which are three to five times those reported in the literature for adhesively bonded 2024 and 7075, are a result of the true metallurgical bond achieved. The effects of heat-treating the bonded material are described and the improvements in bond strength discussed relative to the shear strength of the parent material. The significance of the findings for aerospace applications is discussed