55,857 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
Computer program to generate attitude error equations for a gimballed platform
Computer program for solving attitude error equations related to gimballed platform is described. Program generates matrix elements of attitude error equations when initial matrices and trigonometric identities have been defined. Program is written for IBM 360 computer
Coherent states on spheres
We describe a family of coherent states and an associated resolution of the
identity for a quantum particle whose classical configuration space is the
d-dimensional sphere S^d. The coherent states are labeled by points in the
associated phase space T*(S^d). These coherent states are NOT of Perelomov type
but rather are constructed as the eigenvectors of suitably defined annihilation
operators. We describe as well the Segal-Bargmann representation for the
system, the associated unitary Segal-Bargmann transform, and a natural
inversion formula. Although many of these results are in principle special
cases of the results of B. Hall and M. Stenzel, we give here a substantially
different description based on ideas of T. Thiemann and of K. Kowalski and J.
Rembielinski. All of these results can be generalized to a system whose
configuration space is an arbitrary compact symmetric space. We focus on the
sphere case in order to be able to carry out the calculations in a
self-contained and explicit way.Comment: Revised version. Submitted to J. Mathematical Physic
Coherent states for compact Lie groups and their large-N limits
The first two parts of this article surveys results related to the
heat-kernel coherent states for a compact Lie group K. I begin by reviewing the
definition of the coherent states, their resolution of the identity, and the
associated Segal-Bargmann transform. I then describe related results including
connections to geometric quantization and (1+1)-dimensional Yang--Mills theory,
the associated coherent states on spheres, and applications to quantum gravity.
The third part of this article summarizes recent work of mine with Driver and
Kemp on the large-N limit of the Segal--Bargmann transform for the unitary
group U(N). A key result is the identification of the leading-order large-N
behavior of the Laplacian on "trace polynomials."Comment: Submitted to the proceeding of the CIRM conference, "Coherent states
and their applications: A contemporary panorama.
Regular expressions as violin bowing patterns
String players spend a significant amount of practice time creating and learning bowings. These may be indicated in the music using up-bow and down-bow symbols, but those traditional notations do not capture the complex bowing patterns that are latent within the music. Regular expressions, a mathematical notation for a simple class of formal languages, can describe precisely the bowing patterns that commonly arise in string music. A software tool based on regular expressions enables performers to search for passages that can be handled with similar bowings, and to edit them consistently. A computer-based music editor incorporating bowing patterns has been implemented, using Lilypond to typeset the music. Our approach has been evaluated by using the editor to study ten movements from six violin sonatas by W. A. Mozart. Our experience shows that the editor is successful at finding passages and inserting bowings; that relatively complex patterns occur a number of times; and that the bowings can be inserted automatically and consistently
Suppression of intrinsic neutron background in the Multi-Grid detector
One of the key requirements for neutron scattering instruments is the
Signal-to-Background ratio (SBR). This is as well a design driving requirement
for many instruments at the European Spallation Source (ESS), which aspires to
be the brightest neutron source of the world. The SBR can be effectively
improved with background reduction. The Multi-Grid, a large-area thermal
neutron detector with a solid boron carbide converter, is a novel solution for
chopper spectrometers. This detector will be installed for the three
prospective chopper spectrometers at the ESS. As the Multi-Grid detector is a
large area detector with a complex structure, its intrinsic background and its
suppression via advanced shielding design should be investigated in its
complexity, as it cannot be naively calculated. The intrinsic scattered neutron
background and its effect on the SBR is determined via a detailed Monte Carlo
simulation for the Multi-Grid detector module, designed for the CSPEC
instrument at the ESS. The impact of the detector vessel and the neutron
entrance window on scattering is determined, revealing the importance of an
optimised internal detector shielding. The background-reducing capacity of
common shielding geometries, like side-shielding and end-shielding is
determined by using perfect absorber as shielding material, and common
shielding materials, like BC and Cd are also tested. On the basis of the
comparison of the effectiveness of the different shielding topologies and
materials, recommendations are given for a combined shielding of the Multi-Grid
detector module, optimised for increased SBR.Comment: 26 pages, 18 figures, revise
Experimental realization of a Dirac monopole through the decay of an isolated monopole
We experimentally observe the decay dynamics of deterministically created
isolated monopoles in spin-1 Bose-Einstein condensates. As the condensate
undergoes a change between magnetic phases, the isolated monopole gradually
evolves into a spin configuration hosting a Dirac monopole in its synthetic
magnetic field. We characterize in detail the Dirac monopole by measuring the
particle densities of the spin states projected along different quantization
axes. Importantly, we observe the spontaneous emergence of nodal lines in the
condensate density that accompany the Dirac monopole. We also demonstrate that
the monopole decay accelerates in weaker magnetic field gradients.Comment: 10 pages, 7 figure
Effect of magnetic field on the phase transition in a dusty plasma
The formation of self-consistent crystalline structure is a well-known
phenomenon in complex plasmas. In most experiments the pressure and rf power
are the main controlling parameters in determining the phase of the system. We
have studied the effect of externally applied magnetic field on the
configuration of plasma crystals, suspended in the sheath of a radio-frequency
discharge using the Magnetized Dusty Plasma Experiment (MDPX) device.
Experiments are performed at a fixed pressure and rf power where a crystalline
structure is formed within a confining ring. The magnetic field is then
increased from 0 to 1.28 T. We report on the breakdown of the crystalline
structure with increasing magnetic field. The magnetic field affects the
dynamics of the plasma particles and first leads to a rotation of the crystal.
At higher magnetic field, there is a radial variation (shear) in the angular
velocity of the moving particles which we believe leads to the melting of the
crystal. This melting is confirmed by evaluating the variation of the pair
correlation function as a function of magnetic field.Comment: 9 pages, 5 figure
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