30,393 research outputs found
A steerable UV laser system for the calibration of liquid argon time projection chambers
A number of liquid argon time projection chambers (LAr TPC's) are being build
or are proposed for neutrino experiments on long- and short baseline beams. For
these detectors a distortion in the drift field due to geometrical or physics
reasons can affect the reconstruction of the events. Depending on the TPC
geometry and electric drift field intensity this distortion could be of the
same magnitude as the drift field itself. Recently, we presented a method to
calibrate the drift field and correct for these possible distortions. While
straight cosmic ray muon tracks could be used for calibration, multiple coulomb
scattering and momentum uncertainties allow only a limited resolution. A UV
laser instead can create straight ionization tracks in liquid argon, and allows
one to map the drift field along different paths in the TPC inner volume. Here
we present a UV laser feed-through design with a steerable UV mirror immersed
in liquid argon that can point the laser beam at many locations through the
TPC. The straight ionization paths are sensitive to drift field distortions, a
fit of these distortion to the linear optical path allows to extract the drift
field, by using these laser tracks along the whole TPC volume one can obtain a
3D drift field map. The UV laser feed-through assembly is a prototype of the
system that will be used for the MicroBooNE experiment at the Fermi National
Accelerator Laboratory (FNAL)
Recursive Definitions of Monadic Functions
Using standard domain-theoretic fixed-points, we present an approach for
defining recursive functions that are formulated in monadic style. The method
works both in the simple option monad and the state-exception monad of
Isabelle/HOL's imperative programming extension, which results in a convenient
definition principle for imperative programs, which were previously hard to
define.
For such monadic functions, the recursion equation can always be derived
without preconditions, even if the function is partial. The construction is
easy to automate, and convenient induction principles can be derived
automatically.Comment: In Proceedings PAR 2010, arXiv:1012.455
A Proof Strategy Language and Proof Script Generation for Isabelle/HOL
We introduce a language, PSL, designed to capture high level proof strategies
in Isabelle/HOL. Given a strategy and a proof obligation, PSL's runtime system
generates and combines various tactics to explore a large search space with low
memory usage. Upon success, PSL generates an efficient proof script, which
bypasses a large part of the proof search. We also present PSL's monadic
interpreter to show that the underlying idea of PSL is transferable to other
ITPs.Comment: This paper has been submitted to CADE2
BlogForever D2.6: Data Extraction Methodology
This report outlines an inquiry into the area of web data extraction, conducted within the context of blog preservation. The report reviews theoretical advances and practical developments for implementing data extraction. The inquiry is extended through an experiment that demonstrates the effectiveness and feasibility of implementing some of the suggested approaches. More specifically, the report discusses an approach based on unsupervised machine learning that employs the RSS feeds and HTML representations of blogs. It outlines the possibilities of extracting semantics available in blogs and demonstrates the benefits of exploiting available standards such as microformats and microdata. The report proceeds to propose a methodology for extracting and processing blog data to further inform the design and development of the BlogForever platform
Automated Space Processing Payloads Study. Volume 1: Executive Summary
An investigation is described which examined the extent to which the experiment hardware and operational requirements can be met by automatic control and material handling devices; payload and system concepts are defined which make extensive use of automation technology. Topics covered include experiment requirements and hardware data, capabilities and characteristics of industrial automation equipment and controls, payload grouping, automated payload conceptual design, space processing payload preliminary design, automated space processing payloads for early shuttle missions, and cost and scheduling
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