1,021 research outputs found
Sistemi di trasmissione WiFi per il monitoraggio sismico del Vesuvio
First-year engineering students at the University of Queensland used an interactive webbook to acquire information skills. These helped them search information resources for their projects, which they are required to undertake as part of the subject Introduction to professional engineering. The information skills exercise was an integral part of the project and worth 10% of the overall assessment. The exercises were only available on the Web, allowing the students to enter their answers from home or wherever they had access to the Internet. All answers were marked automatically using a database of all possible answers. Students were able to go back to check their answers. Students were assessed on both their responses to the exercises and also their final bibliography which largely reflected the impact of the webbook. The entire process was evaluated. This paper presents the process and the outcomes of the first-year engineering project involving use of WWW for information skills instruction. The webbooks can be found at http://www.library.uq.edu.au/9e105/
Automatic detection of landslides at Stromboli using neural network analysis of seismic signals
Landslides along the Sciara del Fuoco flank of Stromboli volcano are generally accompanied
by c1istinctive seismic signals which can be used for srudying this phenomenon.
These signals are characterìzed by a spectral content with higher frequencies
and a wider band than the typical explosion quakes and volcanic tremor signals which
are continuously recorded at Stromboli. Furthermore their amplirude envelope usually
shows a cigar-like shape. These two fearures make the detection of such signals quite
easy. The detection of landslides at Stromboli has shown to be an important shortterm
precursor of effusive eruptions. Before the Feb. 27th 2007 eruption, the opening
of the effusive vents was preceded by few hours oI increased occurrence of landslide
signals (Martini et al., 2007). Furthermore since the Sciara del Fuoco has shown significant
instabilities during the 2002-2003 eruption, the automatic detection of landslide
signals is an important monitoring tool for notifying variations in the stability of this
flank. We propose a technique based on a Multi Layer Perceptron (MLP) neural network
which has shown excellent performances. The network is composed of two layer
of neurons, the hidden and the output. The hidden layer is composed of 4 neurons
while the output layer is composed by a single neuron whose output value ranges
between Oand 1, with values higher than a given threshold (e.g. 0.5) meaning positive
detection. The continuous seismic signals are analysed using moving windows of 24 s,
with an overlap of 12 s. For each of these windows the neural output is computed.
The waveforms of each time window are parametrized using both their spectrogram
and their amplirude envelope. The spectrogram is described using the Linear Preclictive
Cocling (L'PC) technique which allows to represent the spectral content using a limited
number of coefficients. The whole signal is c1ivided into 8 sub-windows of 5.12 s
length, with an overlapping of 2.56 s. For each sub-window we compute 6 LPC coefficients,
so each spectrogram is described by only 48 coefficients. The amplirude envelope
is defined by computing the c1ifference between the maximum and minimum value
over 1 s sub-windows obtaining 24 coefficients. In conclusion we use an input vector
composed of 72 elements (48+24). This vector has shown to be an efficient and
compact representation of the raw signal (composed of 1200 samples) (Esposito et al.
2006). The dataset used for determining the network parameters is composed of 537
signals, c1ivided in two classes: 267 landslide signals and 270 other signals (explosions
and tremor). The classification of these signals has been performed by analysts. The training is carried out using subsets of 5/8 of the total dataset. The testing subsets are
composed by the remaining 3/8. The network has shown a performance of about
98.7%. This value is an average over 6 random permutations of the dataset. A preliminary
real-rime automatic system has already been implemented. This system performs
continuous analysis of the seismic signals, publishing them on internal web pages.
It allows a detection of the landslides and a comparison with the past activity on
arbitrary rime intervals
Comparative Analysis of Tandem Repeats from Hundreds of Species Reveals Unique Insights into Centromere Evolution
Centromeres are essential for chromosome segregation, yet their DNA sequences
evolve rapidly. In most animals and plants that have been studied, centromeres
contain megabase-scale arrays of tandem repeats. Despite their importance, very
little is known about the degree to which centromere tandem repeats share
common properties between different species across different phyla. We used
bioinformatic methods to identify high-copy tandem repeats from 282 species
using publicly available genomic sequence and our own data. The assumption that
the most abundant tandem repeat is the centromere DNA was true for most species
whose centromeres have been previously characterized, suggesting this is a
general property of genomes. Our methods are compatible with all current
sequencing technologies. Long Pacific Biosciences sequence reads allowed us to
find tandem repeat monomers up to 1,419 bp. High-copy centromere tandem repeats
were found in almost all animal and plant genomes, but repeat monomers were
highly variable in sequence composition and in length. Furthermore,
phylogenetic analysis of sequence homology showed little evidence of sequence
conservation beyond ~50 million years of divergence. We find that despite an
overall lack of sequence conservation, centromere tandem repeats from diverse
species showed similar modes of evolution, including the appearance of higher
order repeat structures in which several polymorphic monomers make up a larger
repeating unit. While centromere position in most eukaryotes is epigenetically
determined, our results indicate that tandem repeats are highly prevalent at
centromeres of both animals and plants. This suggests a functional role for
such repeats, perhaps in promoting concerted evolution of centromere DNA across
chromosomes
WiFi data transmission system for monitoring volcanic areas: an example application on Mt. Vesuvius
The Seismic Monitoring Network of Mt.Vesuvius, managed by Istituto Nazionale di
Geofisica e Vulcanologia, sezione di Napoli, Osservatorio Vesuviano (INGV-OV), currently
consists of 13 analog short period stations (9 single component and 4 triaxial),
2 digital broadband stations and a permanent seismic array (composed of 16 triaxial
sensors). Moreover 2 dilatometers are installed in the area, that are integrated in the
seismic monitoring system.
The distance among the station and between each station and the data acquisition
center varies from hundreds of meters to some kilometers. Part of the data is collected
in local Data Acquisition Centers (CAD) and then centralized at theMonitoring Center
of INGV-OV.
In recent years, information technology has become fundamental in seismic networks
and geophysical instrumentation, this includes also the data transmission systems. In
this context, the new standards for wireless networks has proved to be a useful tool for
the transmission of geophysical data. This is the reason why we have chosen to adopt
the Wireless Fidelity transmission system, based on available frequencies typical of
the IEEE 802.11h standard, which allows high capacity data traffic.
We have realized different local area networks based on WiFi technology. They can
offer a coverage to high density traffic with extensions varying from a few dozen of
meters to kilometers. Each network can be connected through a concentrator device,
called access points, and a base station, through a high-capacity system of geographic
connectivity, which will be responsible for the liaison to the Monitoring Center of
INGV-OV, where seismic data are centralized. There the data are acquired and analyzed
by automated systems, that produces parametric information in real time.
The architecture of local networks and the backbone for data transmission has been
designed to allow a modular development that is well suited for the needs of continuous
improvement of the network and the introduction of new systems for geophysical
and geochemical volcano monitoring. Currently the infrastructure manages a total of
79 channels with a 24-bit at 100 cps sampling, but the network has a much greater
potential. So the future transition of the seismic network from analog to a fully digital
equipment will be supported by this data transmission system
Traversing the margins of corruption amidst informal economies in Amazonia
This article focuses on local idioms of extra-legal economic activity among indigenous Amazonians in eastern Peru, and its overall argument is that these idioms are part of a broader context in which indigenous people are compelled by a variety of factors to act in a seemingly corrupt manner. I further suggest that within such a context these idioms are not confined to the informal economy but are also used to refer to activities that fall within the formal economy, supporting Hart’s (2009) claim that the informal economy is a way of imagining the orthodox economy. I argue that corruption within Amazonian economies is commonly perceived by non-indigenous people as contrasting with the workings of the orthodox economy without proper consideration of the economic conditions and bureaucratic structures that give rise to it. Lastly, I argue that, here, corruption can contravene bureaucracy by restoring the humanity that Herzfeld (1993) claims bureaucracy rejects through its acts of indifference toward individuals
The Recent Seismicity of Campi Flegrei Caldera (Italy)
Campi Flegrei caldera is located in a very densely populated
area. Half of the city of Naples lies within the caldera
rims with about 350000 people living on this active
volcano. For this reason the surveillance of this volcano
requires advanced monitoring techniques in order to
forecast even minor eruptions. The area was interested
in the period 1982-84 by an unrest crisis with more than
16000 earthquakes and about 2m of ground uplift...INGV;Sezione di Napoli,Osservatorio VesuvianoPublishedTenerife, Canary Islands, Spain1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope
The seismic monitoring network of Mt. Vesuvius
Mt. Vesuvius (southern Italy) is one of the most hazardous volcanoes in the world. Its activity is currently characterized by moderate seismicity, with hypocenters located beneath the crater zone with depth rarely exceeding 5 km and magnitudes generally less than 3. The current configu- ration of the seismic monitoring network of Mt. Vesuvius consists of 18 seismic stations and 7 infrasound microphones. During the period 2006- 2010 a seismic array with 48 channels was also operative. The station distribution provides appropriate coverage of the area around the volcanic edifice. The current development of the network and its geometry, under conditions of low seismic noise, allows locating seismic events with M<1. Remote instruments continuously transmit data to the main acquisition center in Naples. Data transmission is realized using different technological solutions based on UHF, Wi-Fi radio links, and TCP/IP client-server applications. Data are collected in the monitoring center of the Osservatorio Vesuviano (Italian National Institute of Geophysics and Volcanology, Naples section), which is equipped with systems for displaying and analyzing signals, using both real-time automatic and manual procedures. 24-hour surveillance allows to immediately communicate any significant anomaly to the Civil Protection authorities
Scenari di Pericolosità e Danno SPeeD PROJECT -TASK 1.1 Connection of the “Centri Funzionali” of DPC and RC to the monitoring system of INGV-OV
Project specifications;
•Server design & realization for the management of the multiparametric data,alarm and notifications provided by the OV-INGV monitoring system...INGV;DPCUnpublishedRoma1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope
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