671 research outputs found
On the Multi-Instanton Measure for Super Yang--Mills Theories
In this paper we revisit the arguments that have led to the proposal of a
multi-instanton measure for supersymmetric Yang-Mills theories. We then recall
how the moduli space of gauge connections on can be built from a
hyperk\"ahler quotient construction which we generalize to supermanifolds. The
measure we are looking for is given by the supermetric of the supermoduli space
thus introduced. To elucidate the construction we carry out explicit
computations in the case of N=2 supersymmetric Yang-Mills theories.Comment: 28 pages, latex fil
Instanton Calculus, Topological Field Theories and N=2 Super Yang-Mills Theories
The results obtained by Seiberg and Witten for the low-energy Wilsonian
effective actions of N=2 supersymmetric theories with gauge group SU(2) are in
agreement with instanton computations carried out for winding numbers one and
two. This suggests that the instanton saddle point saturates the
non-perturbative contribution to the functional integral. A natural framework
in which corrections to this approximation are absent is given by the
topological field theory built out of the N=2 Super Yang-Mills theory. After
extending the standard construction of the Topological Yang-Mills theory to
encompass the case of a non-vanishing vacuum expectation value for the scalar
field, a BRST transformation is defined (as a supersymmetry plus a gauge
variation), which on the instanton moduli space is the exterior derivative. The
topological field theory approach makes the so-called "constrained instanton"
configurations and the instanton measure arise in a natural way. As a
consequence, instanton-dominated Green's functions in N=2 Super Yang-Mills can
be equivalently computed either using the constrained instanton method or
making reference to the topological twisted version of the theory. We
explicitly compute the instanton measure and the contribution to u=<\Tr
\phi^2> for winding numbers one and two. We then show that each
non-perturbative contribution to the N=2 low-energy effective action can be
written as the integral of a total derivative of a function of the instanton
moduli. Only instanton configurations of zero conformal size contribute to this
result. Finally, the 8k-dimensional instanton moduli space is built using the
hyperkahler quotient procedure, which clarifies the geometrical meaning of our
approach.Comment: latex, 66 page
General purpose readout board {\pi} LUP: overview and results
This work gives an overview of the PCI-Express board LUP, focusing on
the motivation that led to its development, the technological choices adopted
and its performance. The LUP card was designed by INFN and University of
Bologna as a readout interface candidate to be used after the Phase-II upgrade
of the Pixel Detector of the ATLAS and CMS experiments at LHC. The same team in
Bologna is also responsible for the design and commissioning of the ReadOut
Driver (ROD) board - currently implemented in all the four layers of the ATLAS
Pixel Detector (Insertable B-Layer, B-Layer, Layer-1 and Layer-2) - and
acquired in the past years expertise on the ATLAS readout chain and the
problematics arising in such experiments. Although the LUP was designed to
fulfill a specific task, it is highly versatile and might fit a wide variety of
applications, some of which will be discussed in this work. Two
7-generation Xilinx FPGAs are mounted on the board: a Zynq-7 with an
embedded dual core ARM Processor and a Kintex-7. The latter features sixteen
12.5Gbps transceivers, allowing the board to interface easily to any other
electronic board, either electrically and/or optically, at the current
bandwidth of the experiments for LHC. Many data-transmission protocols have
been tested at different speeds, results will be discussed later in this work.
Two batches of LUP boards have been fabricated and tested, two boards in
the first batch (version 1.0) and four boards in the second batch (version
1.1), encapsulating all the patches and improvements required by the first
version.Comment: 6 pages, 10 figures, 21th Real Time Conference, winner of "2018 NPSS
Student Paper Award Second Prize
K-NN FOREST: a software for the non-parametric prediction and mapping of environmental variables by the k-Nearest Neighbors algorithm
In the last decades researchers investigated the possibility of extending the information collected in sampling units during a field survey to wider geographical areas through the use of remotely sensed images. One of the most widely adopted approaches is based on the non-parametric k-Nearest Neighbors (k-NN) algorithm. This contribution describes the software K-NN FOREST we developed to provide a complete tool for the implementation of the k-NN technique to generate spatially explicit estimations (maps) of a response variable acquired in the field by sampling units through the use of remotely sensed data or other ancillary variables. K-NN FOREST is designed to guide the user through a graphic user interface in the different phases of the process. K-NN FOREST is freely available for download and it is designed to run under Windows environment in conjunction with the GIS software IDRISI
K-NN FOREST: a software for the non-parametric prediction and mapping of environmental variables by the k-Nearest Neighbors algorithm
In the last decades researchers investigated the possibility of extending the information collected in sampling units during a field survey to wider geographical areas through the use of remotely sensed images. One of the most widely adopted approaches is based on the non-parametric k-Nearest Neighbors (k-NN) algorithm. This contribution describes the software K-NN FOREST we developed to provide a complete tool for the implementation of the k-NN technique to generate spatially explicit estimations (maps) of a response variable acquired in the field by sampling units through the use of remotely sensed data or other ancillary variables. K-NN FOREST is designed to guide the user through a graphic user interface in the different phases of the process. K-NN FOREST is freely available for download and it is designed to run under Windows environment in conjunction with the GIS software IDRISI
Sviluppo di una procedura innovativa per la cubatura del volume della massa legnosa di fustaie di latifoglie mediante LiDAR
La tecnica di scansione aerea con strumentazione LiDAR (Light Detection and Ranging) è sempre
piĂą presa in considerazione ai fini di analisi e monitoraggio degli attributi dendrometrici dei
popolamenti forestali, ma anche per stimare attributi complessi quali il volume della massa legnosa
e la biomassa legnosa. Il presente contributo propone una procedura innovativa per la stima del
volume di massa legnosa di soprassuoli forestali mediante elaborazione di dati LiDAR in ambiente
GIS, in particolare per i popolamenti a prevalenza di latifoglie dove i convenzionali metodi di stima
basati sulle misurazioni LiDAR dell’altezza dei singoli fusti arborei conducono in genere a risultati
relativamente insoddisfacenti.L'articolo è disponibile sul sito dell'editore http://www.asita.i
The impact of a Clinical Decision Support System on allergen immunotherapy prescription in children and adults with seasonal allergic rhinitis
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