3,858 research outputs found
On the Use of Underspecified Data-Type Semantics for Type Safety in Low-Level Code
In recent projects on operating-system verification, C and C++ data types are
often formalized using a semantics that does not fully specify the precise byte
encoding of objects. It is well-known that such an underspecified data-type
semantics can be used to detect certain kinds of type errors. In general,
however, underspecified data-type semantics are unsound: they assign
well-defined meaning to programs that have undefined behavior according to the
C and C++ language standards.
A precise characterization of the type-correctness properties that can be
enforced with underspecified data-type semantics is still missing. In this
paper, we identify strengths and weaknesses of underspecified data-type
semantics for ensuring type safety of low-level systems code. We prove
sufficient conditions to detect certain classes of type errors and, finally,
identify a trade-off between the complexity of underspecified data-type
semantics and their type-checking capabilities.Comment: In Proceedings SSV 2012, arXiv:1211.587
Radiative corrections to W gamma gamma production at the LHC
Radiative W production at hadron colliders is an important testing ground for
the Standard Model. We consider W gamma gamma production which is sensitive to
the quartic WW gamma gamma coupling. Furthermore the Standard Model amplitude
for this process contains a radiation zero. We present a calculation of the NLO
QCD corrections for W gamma gamma production at the LHC.Comment: 6 pages, talk given at RADCOR 2009 - 9th International Symposium on
Radiative Corrections (Applications of Quantum Field Theory to Phenomenology)
October 25-30 2009, Ascona, Switzerlan
Research on Architectures for Integrated Speech/Language Systems in Verbmobil
The German joint research project Verbmobil (VM) aims at the development of a
speech to speech translation system. This paper reports on research done in our
group which belongs to Verbmobil's subproject on system architectures (TP15).
Our specific research areas are the construction of parsers for spontaneous
speech, investigations in the parallelization of parsing and to contribute to
the development of a flexible communication architecture with distributed
control.Comment: 6 pages, 2 Postscript figure
Full NLO massive gauge boson pair production at the LHC
Electroweak gauge boson pair production is a very important process at the
LHC as it probes the non-abelian structure of electroweak interactions and is a
background process for many searches. We present full next-to-leading order
predictions for the production cross sections and distributions of on-shell
massive gauge boson pair production in the Standard Model, including both QCD
and electroweak corrections. The hierarchy between the ZZ, WW and WZ channels,
observed in the transverse momentum distributions, will be analyzed. We will
also present a comparison with experimental data for the total cross sections
including a study of the theoretical uncertainties.Comment: 4 pages, 4 figures. Proceeding of the inaugural conference "Windows
on the Universe" (August 11-17, Quy Nhon, Vietnam) including updated results
compared to arXiv:1307.433
Estimation of the infinitesimal generator by square-root approximation
For the analysis of molecular processes, the estimation of time-scales, i.e.,
transition rates, is very important. Estimating the transition rates between
molecular conformations is -- from a mathematical point of view -- an invariant
subspace projection problem. A certain infinitesimal generator acting on
function space is projected to a low-dimensional rate matrix. This projection
can be performed in two steps. First, the infinitesimal generator is
discretized, then the invariant subspace is approxi-mated and used for the
subspace projection. In our approach, the discretization will be based on a
Voronoi tessellation of the conformational space. We will show that the
discretized infinitesimal generator can simply be approximated by the geometric
average of the Boltzmann weights of the Voronoi cells. Thus, there is a direct
correla-tion between the potential energy surface of molecular structures and
the transition rates of conformational changes. We present results for a
2d-diffusion process and Alanine dipeptide
NLO corrections to WWZ and ZZZ production at the ILC
We calculate the full one-loop electroweak corrections to tri-boson
production (ZZZ and WWZ) at the ILC. This is important to understand the
Standard Model (SM) gauge quartic couplings which can be a window on the
mechanism of spontaneous symmetry breaking. We find that even after subtracting
the leading QED corrections, the electroweak corrections can still be large
especially as the energy increases.Comment: 7 pages, proceedings of the 3rd CPP Workshop, September 23-25, 2010,
KEK Tsukuba Japa
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