591 research outputs found
A Statistical Approach to Fusing 2-D and 3-D LADAR Systems
LADAR (LAser Detection and Ranging) systems can be used to provide 2-D and 3-D images of scenes. Generally, 2-D images possess superior spatial resolution but without range data due to the density of their focal plane arrays. A 3-D LADAR system can produce range to target data at each pixel, but lacks the 2-D system\u27s superior spatial resolution. The 3-D system is limited by its hardware, specifically its imaging array. Currently developers are investigating ways to change the pixel size in the 3-D LADAR imaging array, but the costs of this research is quite expensive and technically robust. It is the goal of this work to develop an algorithm using an Expectation Maximization approach to estimate both 3-D LADAR range and the bias associated with a 3-D LADAR system. The algorithm developed demonstrates both spatial and range resolution improvement over standard interpolation techniques using both real and simulated 3-D and 2-D LADAR data
Isola di Vulcano (Isole Eolie) movimenti verticali del suolo: livellazione di precisione ottobre 2003
The levelling network installed and managed by the Osservatorio Vesuviano for monitoringvertical ground movements on Volcano island is currently made up of 100 benchmarks(bm) and extends about 24 km as a whole. The reference benchmark for calculating height variations is benchmark 1A located at Volcano Piano, which is a relatively stable area as compared with the northern part of the island. The presently operating network has been enlarged and thickened several times since June 1976, when the first levelling line was installed and surveyed. Twentyseven surveys has been conducted between June 1976 and October 2003. Actually, the configuration of the network presents a greater density of benchmarks in the center-northern sector of the island. The measurement tecnique used is precise levelling. The surveys are performed with autolevelling instruments (Wild NA2) equipped with optical micrometers and invar rods. The last levelling survey has been carried out in the first two weeks of October 2003. The comparison of September 1999 (previous levelling) with October 2003 data indicates a significant subsidence of the center-northern area of the island
The sequences of human and bovine genes of the phosphate carrier from mitochondria contain evidence of alternatively spliced forms.
The sequences of the human and bovine genes for the phosphate carrier from the inner membranes of mitochondria have been determined. The genes have similar structures and each is divided into nine exons. In both genes, two exons, named IIIA and IIIB, are closely related, and they appear to the alternatively spliced. The human exon IIIB sequence is found in a published human heart cDNA sequence, and bovine exon IIIA forms part of a published bovine heart cDNA sequence. By further examination of the human heart cDNA library, sequences arising from both alternatively spliced forms of the phosphate carrier have been characterized. Both forms were also found in several bovine tissues, but the ratios of expression of the two forms varied. The form containing exon IIIA was expressed most highly in bovine heart and liver, less highly in brain and kidney, and only in low amounts in lung. The opposite hierarchy was found for the form containing exon IIIB; it was most highly expressed in lung and least in heart and liver. The alternative splicing mechanism affects amino acids 4-45 of the mature phosphate carrier protein, which is believed to form one of six transmembrane segments of the phosphate carrier and to emerge into a large extramembranous loop. The alternative splicing mechanism changes 13 and 11 amino acids in the human and bovine carrier proteins, respectively. As the function of this region of the phosphate carrier is not known, the effects of the changes on carrier function are not understood at present
The limits of the rotating wave approximation in the electromagnetic field propagation in a cavity
We consider three two-level atoms inside a one-dimensional cavity,
interacting with the electromagnetic field in the rotating wave approximation
(RWA), commonly used in the atom-radiation interaction. One of the three atoms
is initially excited, and the other two are in their ground state. We
numerically calculate the propagation of the field spontaneously emitted by the
excited atom and scattered by the second atom, as well as the excitation
probability of the second and third atom. The results obtained are analyzed
from the point of view of relativistic causality in the atom-field interaction.
We show that, when the RWA is used, relativistic causality is obtained only if
the integrations over the field frequencies are extended to ; on the
contrary, noncausal tails remain even if the number of field modes is
increased. This clearly shows the limit of the RWA in dealing with subtle
problems such as relativistic causality in the atom-field interaction.Comment: 13 pages, 6 figure
Buildings as a seismic source: analysis of a release test at Bagnoli, Italy
Taking advantage of a large displacement-release experiment on a twostory
reinforced concrete building located in Bagnoli (Naples, Italy), we performed
free-field measurements using 3D seismometers, accelerometers, and a 100-m-long
vertical array. The ground motion was noticeable: near the building, the acceleration
exceeded 5% g. At each measurement point, it was possible to recognize two source
terms, due to the tested building and to the reaction structure. The two sources generated
different wave trains. High-frequency accelerations propagated as Rayleigh
waves, whereas 1–2 Hz waves carrying most of the displacement propagated only
as body waves. The experiment lends further support to the hypothesis that buildings
are able to modify substantially the free-field ground motion in their proximity: the
peak ground acceleration we observed is the 20% of the ground acceleration required
to produce a displacement on the building equal to the one imposed during the release
test. We recognize, however, the difficulty of a realistic modeling of wave propagation
in the topmost layer of a densely urbanized area
S.A.G.NET: Rete GPS dell'Appennino meridionale.
The Matese carbonatic massive occupies the northernmost part of the campanian Apennine while Sannio mounts, located to the East of massive, consists primarily of quaternary deposits and represent the area of Apennine chain degrading to East towards the Bradanica foredeep. The area was affected in historical time by several destructive earthquakes. The first ground deformation studies in this area started from 1990-2000 with the definition of geodetic networks, covering all or part of the massive Matese, with the aim of evaluating seismogenic sources responsible for the seismicity of the area. In 2002, a careful inspection of the existing GPS benchmarks was carried out; those which had a good state of preservation and a good level of reliability were included into a new geodetic Matese network, consisting of 38 3D benchmarks. Several surveys were conducted in 2000, 2002 and 2004,with the aim of defining the strain field, defined by plano-altimetric components. In 2005, an intensive work of gathering and validating available data started, integrating data collected by previous surveys with those collected during the new survey carried out in 2006. This work describes in detail the various stages of implementing the final network S.A.G.NET, whose geometry was also bound to the distribution of the known seismogenic sources present in the area. We also show the first results obtained from data collected from2000 to 2006 and the resulting kinematic model for this area
The finite index basis property
We describe in this paper a connection between bifix codes, symbolic dynamical systems and free groups. This is in the spirit of the connection established previously for the symbolic systems corresponding to Sturmian words. We introduce a class of sets of factors of an infinite word with linear factor complexity containing Sturmian sets and regular interval exchange
sets, namely the class of tree sets. We prove as a main result that for a uniformly recurrent tree set S, a finite bifix code X on the alphabet A is S-maximal of S-degree d if and only if it is the basis of a subgroup of index d of the free group on
Overview of the Italian strong Motion database ITACA 1.0
The Italian Strong Motion Database, ITACA, was developed within projects
2 S6 and S4, funded in the framework of the agreements between the Italian Department of
3 Civil Protection (Dipartimento della Protezione Civile, DPC) and the Istituto Nazionale di
4 Geofisica e Vulcanologia (INGV), starting from 2005. The alpha version of the database
5 was released in 2007 and subsequently upgraded to version 1.0 after: (i) including the most
6 recent strongmotion data (from2005 to 2007) recorded in Italy, in addition to the 2008 Parma
7 earthquake, M 5.4, and the M 4.0, 2009 Abruzzo seismic events; (ii) processing the raw
8 strong motion data using an updated procedure; (iii) increasing the number of stations with a
9 measured shear wave velocity profile; (iv) improving the utilities to retrieve time series and
10 ground motion parameters; (v) implementing a tool for selecting time series in agreement
11 with design-response spectra; (vi) compiling detailed station reports containing miscella12
neous information such as photo, maps and site parameters; (vii) developing procedures for
13 the automatic generation of station reports and for the updating of the header files. After such
14 improvements, ITACA 1.0 was published at the web site http://itaca.mi.ingv.it, in 2010. It
15 presently contains 3,955 three-component waveforms, comprising the most complete cata16
logue of the Italian accelerometric records in the period 1972–2007 (3,562 records) and the
17 strongest events in the period 2008–2009. Records were mainly acquired by DPC through its
18 Accelerometric National Network (RAN) and, in few cases, by local networks and temporary
19 stations or networks. This paper introduces the published version of the Italian StrongMotion
20 database (ITACA version 1.0) together with main improvements and new functionalities
- …