1,993 research outputs found
Top Condensation without Fine-Tuning
Quadratic divergencies which lead to the usual fine-tuning or hierarchy
problem are discussed in top condensation models. As in the Standard Model a
cancellation of quadratic divergencies is not possible without the boson
contributions in the radiative corrections which are absent in lowest order of
an -expansion. To deal with the cancellation of quadratic divergencies
we propose therefore an expansion in the flavor degrees of freedom. In leading
order we find the remarkable result that quadratic divergencies automatically
disappear.Comment: LMU - 17/93, in LATEX, 12 pages and 3 pages of figures appended in
Postscrip
Running Neutrino Mass Parameters in See-Saw Scenarios
We systematically analyze quantum corrections in see-saw scenarios, including
effects from above the see-saw scales. We derive approximate renormalization
group equations for neutrino masses, lepton mixings and CP phases, yielding an
analytic understanding and a simple estimate of the size of the effects. Even
for hierarchical masses, they often exceed the precision of future experiments.
Furthermore, we provide a software package allowing for a convenient numerical
renormalization group analysis, with heavy singlets being integrated out
successively at their mass thresholds. We also discuss applications to model
building and related topics.Comment: 49 pages, 9 figures; minor corrections in Sec. 6.5.1; the
accompanying software packages REAP/MPT can be downloaded from
http://www.ph.tum.de/~rg
Active Exploration for Inverse Reinforcement Learning
Inverse Reinforcement Learning (IRL) is a powerful paradigm for inferring a
reward function from expert demonstrations. Many IRL algorithms require a known
transition model and sometimes even a known expert policy, or they at least
require access to a generative model. However, these assumptions are too strong
for many real-world applications, where the environment can be accessed only
through sequential interaction. We propose a novel IRL algorithm: Active
exploration for Inverse Reinforcement Learning (AceIRL), which actively
explores an unknown environment and expert policy to quickly learn the expert's
reward function and identify a good policy. AceIRL uses previous observations
to construct confidence intervals that capture plausible reward functions and
find exploration policies that focus on the most informative regions of the
environment. AceIRL is the first approach to active IRL with sample-complexity
bounds that does not require a generative model of the environment. AceIRL
matches the sample complexity of active IRL with a generative model in the
worst case. Additionally, we establish a problem-dependent bound that relates
the sample complexity of AceIRL to the suboptimality gap of a given IRL
problem. We empirically evaluate AceIRL in simulations and find that it
significantly outperforms more naive exploration strategies.Comment: Presented at Conference on Neural Information Processing Systems
(NeurIPS), 202
Proof-Producing Symbolic Execution for Binary Code Verification
We propose a proof-producing symbolic execution for verification of
machine-level programs. The analysis is based on a set of core inference rules
that are designed to give control over the tradeoff between preservation of
precision and the introduction of overapproximation to make the application to
real world code useful and tractable. We integrate our symbolic execution in a
binary analysis platform that features a low-level intermediate language
enabling the application of analyses to many different processor architectures.
The overall framework is implemented in the theorem prover HOL4 to be able to
obtain highly trustworthy verification results. We demonstrate our approach to
establish sound execution time bounds for a control loop program implemented
for an ARM Cortex-M0 processor
Hand Tracking based on Hierarchical Clustering of Range Data
Fast and robust hand segmentation and tracking is an essential basis for
gesture recognition and thus an important component for contact-less
human-computer interaction (HCI). Hand gesture recognition based on 2D video
data has been intensively investigated. However, in practical scenarios purely
intensity based approaches suffer from uncontrollable environmental conditions
like cluttered background colors. In this paper we present a real-time hand
segmentation and tracking algorithm using Time-of-Flight (ToF) range cameras
and intensity data. The intensity and range information is fused into one pixel
value, representing its combined intensity-depth homogeneity. The scene is
hierarchically clustered using a GPU based parallel merging algorithm, allowing
a robust identification of both hands even for inhomogeneous backgrounds. After
the detection, both hands are tracked on the CPU. Our tracking algorithm can
cope with the situation that one hand is temporarily covered by the other hand.Comment: Technical Repor
Connections between Dynamical and Renormalization Group Techniques in Top Condensation Models
Predictions for the ratio arise in top condensation models from
different methods. One type of prediction stems from Pagels--Stokar relations
based on the use of Ward Identities in the calculation of the \GB decay
constants and expresses in terms of integrals containing the dynamically
generated mass function . Another type of prediction emerges
from the renormalization group equations via infrared quasi--fixed--points of
the running top quark Yukawa coupling. We demonstrate in this paper that in the
limit of a high cutoff these two methods lead to the same predictions for
and in lowest loop order.Comment: Slightly revised version. LaTeX and uuencoded, packed Postscript
figures. The complete paper, including figures, is also available via WWW at
the following http URL
http://www.physik.tu-muenchen.de/tumphy/d/T30d/PAPERS/TUM-HEP-216-95.ps.g
- …