32,531 research outputs found
News from FormCalc and LoopTools
The FormCalc package automates the computation of FeynArts amplitudes up to
one loop including the generation of a Fortran code for the numerical
evaluation of the squared matrix element. Major new or enhanced features in
Version 5 are: iterative build-up of essentially arbitrary phase-spaces
including cuts, convolution with density functions, and uniform treatment of
kinematical variables. The LoopTools library supplies the one-loop integrals
necessary for evaluating the squared matrix element. Its most significant
extensions in Version 2.2 are the five-point family of integrals, and complex
and alternate versions.Comment: 5 pages, to appear in the proceedings of the 7th International
Symposium on Radiative Corrections (RADCOR05), Shonan Village, Japan, 200
Large Margin Object Tracking with Circulant Feature Maps
Structured output support vector machine (SVM) based tracking algorithms have
shown favorable performance recently. Nonetheless, the time-consuming candidate
sampling and complex optimization limit their real-time applications. In this
paper, we propose a novel large margin object tracking method which absorbs the
strong discriminative ability from structured output SVM and speeds up by the
correlation filter algorithm significantly. Secondly, a multimodal target
detection technique is proposed to improve the target localization precision
and prevent model drift introduced by similar objects or background noise.
Thirdly, we exploit the feedback from high-confidence tracking results to avoid
the model corruption problem. We implement two versions of the proposed tracker
with the representations from both conventional hand-crafted and deep
convolution neural networks (CNNs) based features to validate the strong
compatibility of the algorithm. The experimental results demonstrate that the
proposed tracker performs superiorly against several state-of-the-art
algorithms on the challenging benchmark sequences while runs at speed in excess
of 80 frames per second. The source code and experimental results will be made
publicly available
Solution of linear ill-posed problems using overcomplete dictionaries
In the present paper we consider application of overcomplete dictionaries to
solution of general ill-posed linear inverse problems. Construction of an
adaptive optimal solution for such problems usually relies either on a singular
value decomposition or representation of the solution via an orthonormal basis.
The shortcoming of both approaches lies in the fact that, in many situations,
neither the eigenbasis of the linear operator nor a standard orthonormal basis
constitutes an appropriate collection of functions for sparse representation of
the unknown function. In the context of regression problems, there have been an
enormous amount of effort to recover an unknown function using an overcomplete
dictionary. One of the most popular methods, Lasso, is based on minimizing the
empirical likelihood and requires stringent assumptions on the dictionary, the,
so called, compatibility conditions. While these conditions may be satisfied
for the original dictionary functions, they usually do not hold for their
images due to contraction imposed by the linear operator. In what follows, we
bypass this difficulty by a novel approach which is based on inverting each of
the dictionary functions and matching the resulting expansion to the true
function, thus, avoiding unrealistic assumptions on the dictionary and using
Lasso in a predictive setting. We examine both the white noise and the
observational model formulations and also discuss how exact inverse images of
the dictionary functions can be replaced by their approximate counterparts.
Furthermore, we show how the suggested methodology can be extended to the
problem of estimation of a mixing density in a continuous mixture. For all the
situations listed above, we provide the oracle inequalities for the risk in a
finite sample setting. Simulation studies confirm good computational properties
of the Lasso-based technique
IVOA Recommendation: VOTable Format Definition Version 1.3
This document describes the structures making up the VOTable standard. The
main part of this document describes the adopted part of the VOTable standard;
it is followed by appendices presenting extensions which have been proposed
and/or discussed, but which are not part of the standard
Evaluating rules of interaction for object manipulation in cluttered virtual environments
A set of rules is presented for the design of interfaces that allow virtual objects to be manipulated in 3D virtual environments (VEs). The rules differ from other interaction techniques because they focus on the problems of manipulating objects in cluttered spaces rather than open spaces. Two experiments are described that were used to evaluate the effect of different interaction rules on participants' performance when they performed a task known as "the piano mover's problem." This task involved participants in moving a virtual human through parts of a virtual building while simultaneously manipulating a large virtual object that was held in the virtual human's hands, resembling the simulation of manual materials handling in a VE for ergonomic design. Throughout, participants viewed the VE on a large monitor, using an "over-the-shoulder" perspective. In the most cluttered VEs, the time that participants took to complete the task varied by up to 76% with different combinations of rules, thus indicating the need for flexible forms of interaction in such environments
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