28,454 research outputs found
Reducing regression test size by exclusion.
Operational software is constantly evolving. Regression testing is used to identify the unintended consequences of evolutionary changes. As most changes affect only a small proportion of the system, the challenge is to ensure that the regression test set is both safe (all relevant tests are used) and unclusive (only relevant tests are used). Previous approaches to reducing test sets struggle to find safe and inclusive tests by looking only at the changed code. We use decomposition program slicing to safely reduce the size of regression test sets by identifying those parts of a system that could not have been affected by a change; this information will then direct the selection of regression tests by eliminating tests that are not relevant to the change. The technique properly accounts for additions and deletions of code.
We extend and use Rothermel and Harrold’s framework for measuring the safety of regression test sets and introduce new safety and precision measures that do not require a priori knowledge of the exact number
of modification-revealing tests. We then analytically evaluate and compare our techniques for producing reduced regression test sets
Reducing regression test size by exclusion.
Operational software is constantly evolving. Regression testing is used to identify the unintended consequences of evolutionary changes. As most changes affect only a small proportion of the system, the challenge is to ensure that the regression test set is both safe (all relevant tests are used) and unclusive (only relevant tests are used). Previous approaches to reducing test sets struggle to find safe and inclusive tests by looking only at the changed code. We use decomposition program slicing to safely reduce the size of regression test sets by identifying those parts of a system that could not have been affected by a change; this information will then direct the selection of regression tests by eliminating tests that are not relevant to the change. The technique properly accounts for additions and deletions of code.
We extend and use Rothermel and Harrold’s framework for measuring the safety of regression test sets and introduce new safety and precision measures that do not require a priori knowledge of the exact number
of modification-revealing tests. We then analytically evaluate and compare our techniques for producing reduced regression test sets
Letter to Sound Rules for Accented Lexicon Compression
This paper presents trainable methods for generating letter to sound rules
from a given lexicon for use in pronouncing out-of-vocabulary words and as a
method for lexicon compression.
As the relationship between a string of letters and a string of phonemes
representing its pronunciation for many languages is not trivial, we discuss
two alignment procedures, one fully automatic and one hand-seeded which produce
reasonable alignments of letters to phones.
Top Down Induction Tree models are trained on the aligned entries. We show
how combined phoneme/stress prediction is better than separate prediction
processes, and still better when including in the model the last phonemes
transcribed and part of speech information. For the lexicons we have tested,
our models have a word accuracy (including stress) of 78% for OALD, 62% for CMU
and 94% for BRULEX. The extremely high scores on the training sets allow
substantial size reductions (more than 1/20).
WWW site: http://tcts.fpms.ac.be/synthesis/mbrdicoComment: 4 pages 1 figur
Search for Contact Interactions in the Dimuon Final State at ATLAS
The Standard Model has been successful in describing many fundamental aspects
of particle physics. However, there are some remaining puzzles that are not
explained within the context of its present framework. We discuss the
possibility to discover new physics in the ATLAS Detector via a four-fermion
contact interaction, much in the same way Fermi first described Weak
interactions. Using a simple ratio method on dimuon events, we can set a 95%
C.L. lower limit on the effective scale Lambda = 7.5 TeV (8.7 TeV) for the
constructive Left-left Isoscalar Model of quark compositeness with 100 pb^-1
(200 pb^-1) of data at sqrt{s} = 10 TeV.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
A basic lock-in amplifier experiment for the undergraduate laboratory
We describe a basic experiment for the undergraduate laboratory that demonstrates aspects of both, the science and the art of precision electronic measurements. The essence of the experiment is to measure the resistance of a small length of brass-wire to high accuracy using a simple voltage divider and a lock-in amplifier. By performing the measurement at different frequencies and different drive currents, one observes various random noise sources and systematic measurement effects
Gas Gain Measurements from a Negative Ion TPC X-ray Polarimeter
Gas-based time projection chambers (TPCs) have been shown to be highly
sensitive X-ray polarimeters having excellent quantum efficiency while at the
same time achieving large modulation factors. To observe polarization of the
prompt X-ray emission of a Gamma-ray burst (GRB), a large area detector is
needed. Diffusion of the electron cloud in a standard TPC could be prohibitive
to measuring good modulation when the drift distance is large. Therefore, we
propose using a negative ion TPC (NITPC) with Nitromethane (CH3NO2) as the
electron capture agent. The diffusion of negative ions is reduced over that of
electrons due to the thermal coupling of the negative ions to the surrounding
gas. This allows for larger area detectors as the drift distance can be
increased without degrading polarimeter modulation. Negative ions also travel
~200 times slower than electrons, allowing the readout electronics to operate
slower, resulting in a reduction of instrument power. To optimize the NITPC
design, we have measured gas gain with SciEnergy gas electron multipliers
(GEMs) in single and double GEM configurations. Each setup was tested with
different gas combinations, concentrations and pressures: P10 700 Torr, Ne+CO2
700 Torr at varying concentrations of CO2 and Ne+CO2+CH3NO2 700 Torr. We report
gain as a function of total voltage, measured from top to bottom of the GEM
stack, and as a function of drift field strength for the gas concentrations
listed above. Examples of photoelectron tracks at 5.9 keV are also presented.Comment: 6 pages, 6 figures, accepted for publication in IEEE Trans Nucl Sc
Structure, bonding and morphology of hydrothermally synthesised xonotlite
The authors have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically prepared, semicrystalline phase with Ca/Si=1, the authors have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250 degrees C. Analysis in each case was by X-ray photoelectron spectroscopy, environmental scanning electron microscopy and X-ray diffraction. The authors’ use of a much lower water/solid ratio has indirectly confirmed the ‘through solution’ mechanism of xonotlite formation, where silicate dissolution is a key precursor of xonotlite formation. Concerning the role of temperature, too low a temperature (~200 degrees C) fails to yield xonotlite or leads to increased number of structural defects in the silicate chains of xonotlite and too high a temperature (>250 degrees C) leads to degradation of the xonotlite structure, through leaching of interchain calcium. Synthesis duration meanwhile leads to increased silicate polymerisation due to diminishing of the defects in the silicate chains and more perfect crystal morphologies
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