101 research outputs found
Physical Representation-based Predicate Optimization for a Visual Analytics Database
Querying the content of images, video, and other non-textual data sources
requires expensive content extraction methods. Modern extraction techniques are
based on deep convolutional neural networks (CNNs) and can classify objects
within images with astounding accuracy. Unfortunately, these methods are slow:
processing a single image can take about 10 milliseconds on modern GPU-based
hardware. As massive video libraries become ubiquitous, running a content-based
query over millions of video frames is prohibitive.
One promising approach to reduce the runtime cost of queries of visual
content is to use a hierarchical model, such as a cascade, where simple cases
are handled by an inexpensive classifier. Prior work has sought to design
cascades that optimize the computational cost of inference by, for example,
using smaller CNNs. However, we observe that there are critical factors besides
the inference time that dramatically impact the overall query time. Notably, by
treating the physical representation of the input image as part of our query
optimization---that is, by including image transforms, such as resolution
scaling or color-depth reduction, within the cascade---we can optimize data
handling costs and enable drastically more efficient classifier cascades.
In this paper, we propose Tahoma, which generates and evaluates many
potential classifier cascades that jointly optimize the CNN architecture and
input data representation. Our experiments on a subset of ImageNet show that
Tahoma's input transformations speed up cascades by up to 35 times. We also
find up to a 98x speedup over the ResNet50 classifier with no loss in accuracy,
and a 280x speedup if some accuracy is sacrificed.Comment: Camera-ready version of the paper submitted to ICDE 2019, In
Proceedings of the 35th IEEE International Conference on Data Engineering
(ICDE 2019
Live, Personal Data Integration Through UI-Oriented Computing
This paper proposes a new perspective on the problem of data integration on the Web: the one of the Surface Web. It introduces the concept of UI-oriented computing as a computing paradigm whose core ingredient are the user interfaces that build up the SurfaceWeb, and shows how a sensible mapping of data integration tasks to user interface elements and user interactions is able to cope with data integration scenarios that so far have only be conceived for the Deep Web with its APIs and Web services. The described approach provides a novel conceptual and technological framework for practices, such as the integration of data APIs/services and the extraction of content from Web pages, that are common practice but still not adequately supported. The approach targets both programmers and users alike and comes as an extensible, open-source browser extension
Malignant teratoma in Klippel-Feil syndrome: a case report and review of the literature
Introduction: Klippel-Feil syndrome is characterized by a congenital fusion of cervical vertebrae. Intracranial teratomas are nongerminomatous germ cell tumors and they account for 0.3 to 0.9% of all intracranial tumors. Teratomas with malignant transformation refer to lesions which give rise to malignant cancer of somatic type. The association between tumors of dermoid origin and Klippel-Feil malformation is extremely rare. Only 23 other cases have so far been reported, and only one case of dermoid tumor with areas of dedifferentiation on squamous cell carcinoma has been described. Case presentation: We report the case of a 72-year-old white man with a 2-year history of gait and balance disturbances. A brain magnetic resonance imaging revealed a fourth ventricle neoplastic process with infiltrative features. He was operated through a suboccipital craniectomy with a C1 laminotomy and bilateral vertebral artery transposition. At 6-months follow-up, magnetic resonance imaging showed an early regrowth of the fourth ventricle tumor, with the same radiological features. Conclusions: Patients with Klippel-Feil malformation could develop posterior fossa dermoid tumors. The malignant potential of such tumors must be considered and surgery is recommended. Particular attention must be focused on the histopathological analysis in order to identify possible foci of malignant transformation
Geomagnetic field variations at low and high latitude during the January 10-11, 1997 magnetic cloud
On Jan. 10-11, 1997 a wide magnetic cloud
reached the Earth triggering intense geomagnetic activity. Observations performed at low and very high latitude show that the same features appear simultaneously in
correspondence to different changes in the solar wind conditions. In particular, highly polarized modes are simultaneously observed at the same discrete frequencies after the passage of the high density solar wind region following the cloud. SI's and ULF waves polarization are also examined in a wide latitudinal and longitudinal extent
Full one-loop amplitudes from tree amplitudes
We establish an efficient polynomial-complexity algorithm for one-loop
calculations, based on generalized -dimensional unitarity. It allows
automated computations of both cut-constructible {\it and} rational parts of
one-loop scattering amplitudes from on-shell tree amplitudes. We illustrate the
method by (re)-computing all four-, five- and six-gluon scattering amplitudes
in QCD at one-loop.Comment: 27 pages, revte
Geomagnetic field observations at a new Antarctic site, within the AIMNet project
During the 2007-2008 antarctic campaign, the Italian PNRA installed a Low Power Magnetometer within the
framework of the AIMNet (Antarctic International Magnetometer Network) project, proposed and coordinated
by BAS. The magnetometer is situated at Talos Dome, around 300 km geographically North-West from Mario
Zucchelli Station (MZS), and approximately at the same geomagnetic latitude as MZS. In this work we present a
preliminary analysis of the geomagnetic field 1-min data, and a comparison with simultaneous data from different
Antarctic stations
NNLO massive corrections to Bhabha scattering and theoretical precision of BabaYaga@NLO
We provide an exact calculation of next-to-next-to-leading order (NNLO)
massive corrections to Bhabha scattering in QED, relevant for precision
luminosity monitoring at meson factories. Using realistic reference event
selections, exact numerical results for leptonic and hadronic corrections are
given and compared with the corresponding approximate predictions of the event
generator BabaYaga@NLO. It is shown that the NNLO massive corrections are
necessary for luminosity measurements with per mille precision. At the same
time they are found to be well accounted for in the generator at an accuracy
level below the one per mille. An update of the total theoretical precision of
BabaYaga@NLO is presented and possible directions for a further error reduction
are sketched.Comment: 5 pages, 3 tables, contrib. to proceedings of International Workshop
on e+e- collisions: from Phi to Psi, PHIPSI11, BINP, Novosibirsk, Russia,
September 19-22, 201
Feynman Rules for the Rational Part of the QCD 1-loop amplitudes
We compute the complete set of Feynman Rules producing the Rational Terms of
kind R_2 needed to perform any QCD 1-loop calculation. We also explicitly check
that in order to account for the entire R_2 contribution, even in case of
processes with more than four external legs, only up to four-point vertices are
needed. Our results are expressed both in the 't Hooft Veltman regularization
scheme and in the Four Dimensional Helicity scheme, using explicit color
configurations as well as the color connection language.Comment: 18 pages, 11 figures. Misprints corrected in Appendix A. Version to
be published in JHE
Polarizing the Dipoles
We extend the massless dipole formalism of Catani and Seymour, as well as its
massive version as developed by Catani, Dittmaier, Seymour and Trocsanyi, to
arbitrary helicity eigenstates of the external partons. We modify the real
radiation subtraction terms only, the primary aim being an improved efficiency
of the numerical Monte Carlo integration of this contribution as part of a
complete next-to-leading order calculation. In consequence, our extension is
only applicable to unpolarized scattering. Upon summation over the helicities
of the emitter pairs, our formulae trivially reduce to their original form. We
implement our extension within the framework of Helac-Phegas, and give some
examples of results pertinent to recent studies of backgrounds for the LHC. The
code is publicly available. Since the integrated dipole contributions do not
require any modifications, we do not discuss them, but they are implemented in
the software.Comment: 20 pages, 4 figures, Integrated dipoles implemented for massless and
massive case
Multi-gluon helicity amplitudes with one off-shell leg within high energy factorization
Basing on the Slavnov-Taylor identities, we derive a new prescription to
obtain gauge invariant tree-level scattering amplitudes for the process g*g->Ng
within high energy factorization. Using the helicity method, we check the
formalism up to several final state gluons, and we present analytical formulas
for the the helicity amplitudes for N=2. We also compare the method with
Lipatov's effective action approach.Comment: 25 pages, quite a few figures, an appendix added, typos correcte
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