The miracle as a randomization device: a lesson from Richard Wagner's romantic opera Tannhauser und der Sankerkrieg auf Wartburg

In this paper we provide textual evidence on the sophistication of medieval deterrence strategies. Drawing on one of the great opera librettos based on medieval sources, Wagner’s Tannhäuser, we shall illustrate the use of optimal randomization strategies that can be derived by applying notions of dominance or trembling-hand perfection. Particular attention is paid to the employed randomization device

Twin-photon techniques for fiber measurements

The potential of twin photons generated by parametric down-conversion for metrological applications are discussed. We present several experimental results like the measurement of chromatic dispersion and polarization mode dispersion in optical fibers.Comment: 6 pages, 5 figures, Invited paper for the Symposium on Optical Fiber Measurements, sponsored by NIST, Boulder, Co, September 15-17, 199

Using Non-Parametric Tests to Evaluate Traffic Forecasting Performance.

This paper proposes the use of a number of nonparametric comparison methods for evaluating traffic flow forecasting techniques. The advantage to these methods is that they are free of any distributional assumptions and can be legitimately used on small datasets. To demonstrate the applicability of these tests, a number of models for the forecasting of traffic flows are developed. The one-step-ahead forecasts produced are then assessed using nonparametric methods. Consideration is given as to whether a method is universally good or good at reproducing a particular aspect of the original series. That choice will be dictated, to a degree, by the user’s purpose for assessing traffic flow

Digital system detects binary code patterns containing errors

System of square loop magnetic cores associated with code input registers to react to input code patterns by reference to a group of control cores in such a manner that errors are canceled and patterns containing errors are accepted for amplification and processing. This technique improves reception capabilities in PCM telemetry systems

Isotopic ratios at z=0.68 from molecular absorption lines toward B 0218+357

Isotopic ratios of heavy elements are a key signature of the nucleosynthesis processes in stellar interiors. The contribution of successive generations of stars to the metal enrichment of the Universe is imprinted on the evolution of isotopic ratios over time. We investigate the isotopic ratios of carbon, nitrogen, oxygen, and sulfur through millimeter molecular absorption lines arising in the z=0.68 absorber toward the blazar B 0218+357. We find that these ratios differ from those observed in the Galactic interstellar medium, but are remarkably close to those in the only other source at intermediate redshift for which isotopic ratios have been measured to date, the z=0.89 absorber in front of PKS1830-211. The isotopic ratios in these two absorbers should reflect enrichment mostly from massive stars, and they are indeed close to the values observed toward local starburst galaxies. Our measurements set constraints on nucleosynthesis and chemical evolution models.Comment: Accepted for publication in Astronomy & Astrophysics; 10 pages, 9 figure

Die Republiek van Suid-Afrika in die veranderde wêreld

Die tema van my referaat is die Republiek van Suid-Afrika in die veranderde wêreld. Dis ’n baie wye onderwerp en ek sal slegs sekere aspekte daarvan kan behandel. Ter inleiding wil ek kortliks stilstaan by die sogenaamde veranderde wêreld. Suid-Afrika se regstreekse optrede op die internasionale terrein dateer vir praktiese doeleindes van die skepping van die Departement van Buitelandse Sake in 1927 af. In daardie beginjare was ons optrede betreklik beperk en in ’n groot mate bepaal deur ons lidmaatskap van die destydse Britse Gemenebes

Quantum double of a (locally) compact group

We generalise the quantum double construction of Drinfel'd to the case of the (Hopf) algebra of suitable functions on a compact or locally compact group. We will concentrate on the *-algebra structure of the quantum double. If the conjugacy classes in the group are countably separated, then we classify the irreducible *-representations by using the connection with so-called transformation group algebras. For finite groups, we will compare our description to the result of Dijkgraaf, Pasquier and Roche. Finally we will work out the explicit examples of SU(2) and SL(2,R).Comment: LaTeX2e, 18 pages. Univ. of Amsterdam, Depts. of Math. and of Theor.Phys., to be published in the Journal of Lie Theor

Tensor product representations of the quantum double of a compact group

We consider the quantum double D(G) of a compact group G, following an earlier paper. We use the explicit comultiplication on D(G) in order to build tensor products of irreducible *-representations. Then we study their behaviour under the action of the R-matrix, and their decomposition into irreducible *-representations. The example of D(SU(2)) is treated in detail, with explicit formulas for direct integral decomposition (`Clebsch-Gordan series') and Clebsch-Gordan coefficients. We point out possible physical applications.Comment: LaTeX2e, 27 pages, corrected references, accepted by Comm.Math.Phy