12,426 research outputs found
Target Directed Event Sequence Generation for Android Applications
Testing is a commonly used approach to ensure the quality of software, of
which model-based testing is a hot topic to test GUI programs such as Android
applications (apps). Existing approaches mainly either dynamically construct a
model that only contains the GUI information, or build a model in the view of
code that may fail to describe the changes of GUI widgets during runtime.
Besides, most of these models do not support back stack that is a particular
mechanism of Android. Therefore, this paper proposes a model LATTE that is
constructed dynamically with consideration of the view information in the
widgets as well as the back stack, to describe the transition between GUI
widgets. We also propose a label set to link the elements of the LATTE model to
program snippets. The user can define a subset of the label set as a target for
the testing requirements that need to cover some specific parts of the code. To
avoid the state explosion problem during model construction, we introduce a
definition "state similarity" to balance the model accuracy and analysis cost.
Based on this model, a target directed test generation method is presented to
generate event sequences to effectively cover the target. The experiments on
several real-world apps indicate that the generated test cases based on LATTE
can reach a high coverage, and with the model we can generate the event
sequences to cover a given target with short event sequences
Quantum molecular dynamics simulations of the thermophysical properties of shocked liquid ammonia for pressures up to 1.3 TPa
We investigate via quantum molecular-dynamics simulations the thermophysical
properties of shocked liquid ammonia up to the pressure 1.3 TPa and temperature
120000 K. The principal Hugoniot is predicted from wide-range equation of
state, which agrees well with available experimental measurements up to 64 GPa.
Our systematic study of the structural properties demonstrates that liquid
ammonia undergoes a gradual phase transition along the Hugoniot. At about 4800
K, the system transforms into a metallic, complex mixture state consisting of
, , ,
N, and H. Furthermore, we discuss the implications for the interiors of Uranus
and Neptune.Comment: 16 pages, 8 figures. arXiv admin note: text overlap with
arXiv:1012.488
SL(2,C) gravity on noncommutative space with Poisson structure
The Einstein's gravity theory can be formulated as an SL(2,C) gauge theory in
terms of spinor notations. In this paper, we consider a noncommutative space
with the Poisson structure and construct an SL(2,C) formulation of gravity on
such a space. Using the covariant coordinate technique, we build a gauge
invariant action in which, according to the Seiberg-Witten map, the physical
degrees of freedom are expressed in terms of their commutative counterparts up
to the first order in noncommutative parameters.Comment: 12 pages, no figures; v2: 13 pages, clarifications and references
added; v3: clarifications added; v4: more clarifications and references
added, final version to appear in Phys. Rev.
Electric Field Effect Tuning of Electron-Phonon Coupling in Graphene
Gate-modulated low-temperature Raman spectra reveal that the electric field
effect (EFE), pervasive in contemporary electronics, has marked impacts on long
wavelength optical phonons of graphene. The EFE in this two dimensional
honeycomb lattice of carbon atoms creates large density modulations of carriers
with linear dispersion (known as Dirac fermions). Our EFE Raman spectra display
the interactions of lattice vibrations with these unusual carriers. The changes
of phonon frequency and line-width demonstrate optically the particle-hole
symmetry about the charge-neutral Dirac-point. The linear dependence of the
phonon frequency on the EFE-modulated Fermi energy is explained as the
electron-phonon coupling of mass-less Dirac fermions.Comment: 4 pages, 4 figure
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