2,130 research outputs found
Recent developments in predictive uncertainty assessment based on the model conditional processor approach
Abstract. The work aims at discussing the role of predictive uncertainty in flood forecasting and flood emergency management, its relevance to improve the decision making process and the techniques to be used for its assessment. Real time flood forecasting requires taking into account predictive uncertainty for a number of reasons. Deterministic hydrological/hydraulic forecasts give useful information about real future events, but their predictions, as usually done in practice, cannot be taken and used as real future occurrences but rather used as pseudo-measurements of future occurrences in order to reduce the uncertainty of decision makers. Predictive Uncertainty (PU) is in fact defined as the probability of occurrence of a future value of a predictand (such as water level, discharge or water volume) conditional upon prior observations and knowledge as well as on all the information we can obtain on that specific future value from model forecasts. When dealing with commensurable quantities, as in the case of floods, PU must be quantified in terms of a probability distribution function which will be used by the emergency managers in their decision process in order to improve the quality and reliability of their decisions. After introducing the concept of PU, the presently available processors are introduced and discussed in terms of their benefits and limitations. In this work the Model Conditional Processor (MCP) has been extended to the possibility of using two joint Truncated Normal Distributions (TNDs), in order to improve adaptation to low and high flows. The paper concludes by showing the results of the application of the MCP on two case studies, the Po river in Italy and the Baron Fork river, OK, USA. In the Po river case the data provided by the Civil Protection of the Emilia Romagna region have been used to implement an operational example, where the predicted variable is the observed water level. In the Baron Fork River example, the data set provided by the NOAA's National Weather Service, within the DMIP 2 Project, allowed two physically based models, the TOPKAPI model and TETIS model, to be calibrated and a data driven model to be implemented using the Artificial Neural Network. The three model forecasts have been combined with the aim of reducing the PU and improving the probabilistic forecast taking advantage of the different capabilities of each model approach
Microdistribution of macroinvertebrates in a temporary pond of Central Italy: Taxonomic and functional analyses
Spatial distribution of physical and chemical variables and macroinvertebrate composition, structure and functional aspects were investigated in five microhabitats available (Ranunculus acquatilis+ Ranunculus sardous, Spirogyra sp., Juncus effusus, and unvegetated littoral sediments and central sediments) in a temporary pond near Rome during spring 2004. The central sediments were found to differ greatly from the other substrates. They were characterized by higher nutrient contents (total P, total N), organic matter and organic C, and silt and clay in the sediments, and lower dissolved oxygen content and lower pH in the water. Species richness and densities of total macrofauna showed the lowest values in central sediments and the highest ones in submerged macrophytes (Ranunculus spp.) and emergent vegetation (Juncus effusus). Oligochaeta Tubificidae, some Nematoda (Dorylaimus spp.), and Chironomidae Tanypodinae (Procladius sp. and Psectrotanypus varius) and Chironominae (Chironomus plumosus group) characterized the central sediments, whereas Ephemeroptera and most of the Odonata and Coleoptera species were commonly found in submerged macrophyte beds. Some species of Coleoptera and Hemiptera (Hygrobia hermanni, Helochares lividus, Berosus signaticollis and Gerris maculatus) were mainly found in the algal substratum, and some Nematoda species (Tobrilus spp. and Aporcelaimellus obtusicaudatus), Oligochaeta Enchytraeidae, young larvae of Sympetrum and Diptera Ceratopogonidae in littoral sediments. Juncus effusus appeared to be mainly colonized by Chironomidae Orthocladiinae (Psectrocladius sordidellus group and Cotynoneura scutellata) and Tanytarsini (Paratanytarsus sp.). Central sediments also favoured high abundances of collector-gatherers, burrowers and drought resistant forms with passive dispersal, whereas Ranunculus spp. hosted mainly scrapers, shredders, swimmers+divers and active dispersal forms without any resistant stages to desiccation. Juncus plants were mostly colonized by collector-filterers and by organisms capable of both active dispersal and surviving desiccation. Littoral sediments and algae showed similar functional organization and intermediate features between central sediments and submerged macrophyte beds. All these results demonstrate that microhabitat characteristics play a crucial role in selecting macroinvertebrate taxa according to their environmental requirement, feeding mechanism, movement and resistance to drought. Moreover, our study confirms the role of submerged and emergent vegetation in maintaining high biodiversity and suggests that all microhabitats should be considered to provide both an exhaustive collection of species for pond management and conservation and basic insights into the functioning of pond communities. (C) 2009 Elsevier GmbH. All rights reserved
Dark Matter searches using gravitational wave bar detectors: quark nuggets and newtorites
Many experiments have searched for supersymmetric WIMP dark matter, with null
results. This may suggest to look for more exotic possibilities, for example
compact ultra-dense quark nuggets, widely discussed in literature with several
different names. Nuclearites are an example of candidate compact objects with
atomic size cross section. After a short discussion on nuclearites, the result
of a nuclearite search with the gravitational wave bar detectors Nautilus and
Explorer is reported. The geometrical acceptance of the bar detectors is 19.5
sr, that is smaller than that of other detectors used for similar
searches. However, the detection mechanism is completely different and is more
straightforward than in other detectors. The experimental limits we obtain are
of interest because, for nuclearites of mass less than g, we find a
flux smaller than that one predicted considering nuclearites as dark matter
candidates. Particles with gravitational only interactions (newtorites) are
another example. In this case the sensitivity is quite poor and a short
discussion is reported on possible improvements.Comment: published on Astroparticle Physics Sept 25th 2016 replaced fig 1
Demand Side Management analysis of a commercial Water Loop Heat Pump system
Demand side management (DSM) can be defined as a set of measures adopted to modify customers\u2019 energy
demand with the aim of improving the efficiency of the overall energy system. Indeed, DSM strategies can be
used to reduce customers\u2019 demand at peak times, reduce energy consumption seasonally/yearly, change the
timing of end-use consumption from high to low-cost periods, and increase consumption during off-peak
periods. DSM strategies can be implemented by using the energy flexibility available in the final users\u2019
applications, e.g. the thermal inertia of the building mass, the presence of additional energy storage systems
enabling load shaping or the use of control systems to turn on/off end-users\u2019 devices when required.
Being intensive energy consumers because of a high electric energy demand (mainly for refrigeration, which
accounts for about 40 % of the yearly energy consumption), supermarkets are ideal candidates for energy use
optimizations obtained through a DSM approach.
This work shows the results of a DSM analysis carried out for a refrigeration and HVAC plant in a
supermarket coupled with a Water Loop Heat Pump (WLHP) system. The water loop is used as a heat
source/sink for the refrigeration unit supplying the cooling capacity required by food preservation and for
several heat pumps that provide heating/cooling inside the supermarket building. The system is modelled in
TRNSYS and the role of the water loop and its thermal inertia to provide energy flexibility is investigated. The
system design and control strategy are modified in order to reduce the electricity costs in presence of demand
response programs based on real-time price mechanisms
Poner en escena el patrimonio tangible e intangible
Museums and exhibition centres acquire, conserve, communicate and exhibit the tangible and intangible heritage of humanity and its environment, in order to tangible and intangible heritage of humanity and its environment, with the fundamental purpose of promoting and stimulating study, education and to promote and stimulate study, education and contemplation. Los Museos y centros expositivos adquieren, conservan, comunican y exponen el patrimonio tangible e intangible de la humanidad y su ambiente, con el propósito fundamental de promover y estimular el estudio, la educación y la contemplación. I musei e i centri espositivi acquisiscono, conservano, comunicano ed espongono il patrimonio materiale e immateriale dell'umanità e del suo ambiente, con lo scopo fondamentale di promuovere e stimolare lo studio, l'educazione e la contemplazione. 
Quark nuggets search using 2350 Kg gravitational waves aluminum bar detectors
The gravitational wave resonant detectors can be used as detectors of quark
nuggets, like nuclearites (nuclear matter with a strange quark). This search
has been carried out using data from two 2350 Kg, 2 K cooled, aluminum bar
detectors: NAUTILUS, located in Frascati (Italy), and EXPLORER, that was
located in CERN Geneva (CH). Both antennas are equipped with cosmic ray shower
detectors: signals in the bar due to showers are continuously detected and used
to characterize the antenna performances. The bar excitation mechanism is based
on the so called thermo-acoustic effect, studied on dedicated experiments that
use particle beams. This mechanism predicts that vibrations of bars are induced
by the heat deposited in the bar from the particle. The geometrical acceptance
of the bar detectors is 19.5 sr, that is smaller than that of other
detectors used for similar searches. However, the detection mechanism is
completely different and is more straightforward than in other detectors. We
will show the results of ten years of data from NAUTILUS (2003-2012) and 7
years from EXPLORER (2003-2009). The experimental limits we obtain are of
interest because, for nuclearites of mass less than grams, we find a
flux smaller than that one predicted considering nuclearites as dark matter
candidates.Comment: presented to the 33rd International Cosmic Ray Conference Rio de
Janeiro 201
- …