Magnetic field and current distributins in melt-textured YBa 2Cu 3O 7-x with an artificial grain boundary

Using a magneto-optical (MO) technique, magnetic field distributions have been measured in a melt-textured YBa 2Cu 3O 7-x bulk superconductor, joined to form an artificial grain boundary (GB), in an external magnetic field perpendicular to the sample surface. The magnetic field at a weak section of the GB shows different values between the field increasing up to 150mT and decreasing down to 0T after zero-field-cooling. Namely, the magnetic field in increasing field is higher than that in decreasing field, even in the same external field. This result supports a model in which such differences in magnetic field at the weak-link GB give rise to the hysteresis behavior in the field dependence of transport critical current density in polycrystalline samples. The field distributions across a well-joined region of the GB behave similarly to the adjoining bulk material and this result indicates the possibility of creating useful artifacts provided that the strongly coupled sections can be reproduced on a larger scale.

Bayesian dialogue system for the let's go spoken dialogue challenge

This paper describes how Bayesian updates of dialogue state can be used to build a bus information spoken dialogue system. The resulting system was deployed as part of the 2010 Spoken Dialogue Challenge. The purpose of this paper is to describe the system, and provide both simulated and human evaluations of its performance. In control tests by human users, the success rate of the system was 24.5% higher than the baseline Lets Go! system. ©2010 IEEE.