6,403 research outputs found
Big Data Analytics for QoS Prediction Through Probabilistic Model Checking
As competitiveness increases, being able to guaranting QoS of delivered
services is key for business success. It is thus of paramount importance the
ability to continuously monitor the workflow providing a service and to timely
recognize breaches in the agreed QoS level. The ideal condition would be the
possibility to anticipate, thus predict, a breach and operate to avoid it, or
at least to mitigate its effects. In this paper we propose a model checking
based approach to predict QoS of a formally described process. The continous
model checking is enabled by the usage of a parametrized model of the monitored
system, where the actual value of parameters is continuously evaluated and
updated by means of big data tools. The paper also describes a prototype
implementation of the approach and shows its usage in a case study.Comment: EDCC-2014, BIG4CIP-2014, Big Data Analytics, QoS Prediction, Model
Checking, SLA compliance monitorin
Simplified conservative testing method of touch and step voltages by multiple auxiliary electrodes at reduced distance
Grounding systems (GSs) must be tested periodically in order to maintain the touch voltage (TV) and step voltage (SV) below a safe value in all of the zones of the installation. Measurements of the ground resistance and of the TV and SV are typically done by the fall-of-potential (FoP) method, locating the auxiliary current electrode at remote distance to test the effective behavior of the GS. In urban areas, it could be very complicated or impossible to install the auxiliary current electrode as required, not having area around with sufficient accessibility. At this aim, this paper describes a methodology of using multiple current electrodes at short distances, modifying the classic FoP practice, so that the measurements of TV and SV are always conservative. The adequacy of a GS is verified if the values of the TV and SV, tested inside and in the vicinity of the GS, are below the permissible limits, regardless if they are true or conservatively increased. Thus, the measured TV and SV by the suggested method, always conservative, allow verifying the adequacy of GSs, in the cases where it is impossible to locate the remote auxiliary electrode
Performances of the Italian seismic network, 1985-2002: the hidden thing
Seismic data users and people managing a sesimic network are both interested
in the potentiality of the data, with the difference that the former look at
stability, the second at improvements. In this work we measure the performances
of the Italian Telemetered Seismic Network in 1985-2002 by defining basic
significant parameters and studying their evolution during the years. Then, we
deal with the geological methods used to characterise or to plan a seismic
station deployment in a few cases. Last, we define the gain of the network as
the percentage of located earthquakes with respect to the total recorded
earthquakes. By analysing the distribution of non-located ("missed")
earthquakes, we suggest possible actions to take in order to increase the gain.
Results show that completeness magnitude is 2.4 in the average over the
analysed period, and it can be as low as 2.2 when we consider non-located
earthquakes as well. Parameters such as the distance between an earthquake and
the closest station, and the RMS location decrease with time, reflecting
improvements in the location quality. Methods for geologic and seismological
characterisation of a possible station site also proved to be effective.
Finally, we represent the number of missed earthquakes at each station, showing
that nine stations control more that 50% of all missed earthquakes, and
suggesting areas in Italy where the network might be easily improved.Comment: 17 pages, 1 table, 11 figures. Submitted to Annals of Geophysic
Soil quality evaluation under agro-silvo-pastoral Mediterranean management systems
According to Franzluebber (2002) the degree of stratification of soil organic C and N, as well as other parameters, with soil depth, expressed as a ratio, can indicate soil quality or soil ecosystem functioning and sustainability under different agricultural management. Stratification ratios > 2 indicate a higher soil quality and contribution to agriculture sustainability. A case study from northeastern Sardinia (Italy) is presented
Neural Network Aided Glitch-Burst Discrimination and Glitch Classification
We investigate the potential of neural-network based classifiers for
discriminating gravitational wave bursts (GWBs) of a given canonical family
(e.g. core-collapse supernova waveforms) from typical transient instrumental
artifacts (glitches), in the data of a single detector. The further
classification of glitches into typical sets is explored.In order to provide a
proof of concept,we use the core-collapse supernova waveform catalog produced
by H. Dimmelmeier and co-Workers, and the data base of glitches observed in
laser interferometer gravitational wave observatory (LIGO) data maintained by
P. Saulson and co-Workers to construct datasets of (windowed) transient
waveforms (glitches and bursts) in additive (Gaussian and compound-Gaussian)
noise with different signal-tonoise ratios (SNR). Principal component analysis
(PCA) is next implemented for reducing data dimensionality, yielding results
consistent with, and extending those in the literature. Then, a multilayer
perceptron is trained by a backpropagation algorithm (MLP-BP) on a data subset,
and used to classify the transients as glitch or burst. A Self-Organizing Map
(SOM) architecture is finally used to classify the glitches. The glitch/burst
discrimination and glitch classification abilities are gauged in terms of the
related truth tables. Preliminary results suggest that the approach is
effective and robust throughout the SNR range of practical interest.
Perspective applications pertain both to distributed (network, multisensor)
detection of GWBs, where someintelligenceat the single node level can be
introduced, and instrument diagnostics/optimization, where spurious transients
can be identified, classified and hopefully traced back to their entry point
Sistemi di trasporto pubblico urbano via mare. Un modo per rilanciare il waterfront di Palermo
New sea transport terminals can be major people movers and main centres for various urban activities and functions, determining strong social output. The city of Palermo qualifies as a prominent research territory, due to its densely urbanized and populated waterfront areas, associated with a lack of transport infrastructures and efficient transit systems to meet the mobility demand of residents and commuters. A new waterfront arrangement can improve the city image and opens the way to new urban public transport systems by sea, like ferries and hydrofoils, as an alternative to the conventional land transit systems already affected by unavoidable congestion. Plans to link by sea different destination on the coast, should first identify and locate the several historical docking points of the city, as they will be the connections between the land transit systems and the sea. Local cultural heritage, handicraft, architecture and natural aspects, can be attractions for the sea transit users, occasional visitors, tourists and passengers on a cruise. The basic idea is to create a sea lane independent from the usual land routes which are highly congested by the daily massive and repeated movements of residents, between the south-west and the north-west of Palermo
Experimental characterization of dacron 360 woven constitutive behavior
In the present paper some experimental analyses of Dacron© 360 woven aimed to
characterize its constitutive behavior are presented. This woven, widely adopted in sail
manufacturing, is obtained by weaving polyethylene terephthalate (PET) yarn and it shows
some peculiar features due to the manufacturing process. The experimental tests, in terms of
tensile tests and cyclic tests, clearly show the orthotropy features of the material, its high
strength and deformability. Finally, the examination with optical microscope of the tested
specimens allows to evidence how the warp and weft yarns interact
Selection and Gratitude: Anonymity and gratitude
What kind of candidate is selected into a job when the principal has to appoint a
committee to measure the candidate's ability and select a winner through a call specifying
a wage for the job? In a model where the principal fixes the wage anticipating the
committee's choice, under a rather natural assumption about the committee's objective
we find that if the committee takes into account the candidate's gratitude a candidate
with less than first best ability will be selected in equilibrium. First best selection is
achieved if the committee is anonymous to the candidates. If the committee could also
set the wage the first best candidate would be selected, but the principal would be worse
off hence he would not implement full delegation
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