1,720,970 research outputs found
Una piattaforma open source per la navigazione indoor: applicazione alla facoltà di ingegneria civile e industriale dell'università di Roma "Sapienza"
Full text link“Il conferire struttura e identità all’ambiente è una capacità vitale propria di tutti gli animali dotati di movimento” (Lynch, 1964).
È proprio da questo che prende spunto l’idea del progetto qui proposto, dal tentativo di riproporre su un foglio il territorio che si
abita, dando specifico ordine agli elementi; in quanto è proprio l’assenza di smarrimento e la capacità di orientarsi a darci un senso di equilibrio e benessere. “La stessa parola smarrito significa, nella nostra lingua, molto di più che semplice incertezza geografica: essa porta con sé sfumature di vera tragedia. [...] si potrebbe obiettare, che il cervello umano è meravigliosamente adattabile. [...] eppure, anche il mare ha il sole e le stelle, i venti, le correnti, gli uccelli e il colore dell’acqua senza i quali la navigazione sarebbe impossibile.” (Lynch, 1964)
La cartografia riveste un ruolo di fondamentale importanza per tutti i dati di tipo geografico, i dati cioè che presentano come
caratteristica principale un attributo spaziale; i fenomeni descrivibili a partire dal loro posizionamento vengono detti
georeferenziabili. La cartografia, pertanto, si occupa dell'archiviazione (e della rappresentazione) di dati georeferenziabili; essa mira, dunque, a fornire una conoscenza del territorio sia di tipo puntuale che generale, a sviluppare processi logici in funzione di relazioni e a fungere da supporto di base per pianificazione, progettazione e gestione del territorio. (Brovelli, 2000)
È in questo contesto che si inserisce il progetto in oggetto, nel tentativo di fornire uno strumento utile e potente che consenta al singolo utente di orientarsi in tempo reale, e quindi supportando la vera e propria navigazione, in aree non caratterizzate da copertura GNSS. Il progetto qui riportato propone l’utilizzo di una piattaforma open source per supportare la navigazione indoor, e ne mostra un’applicazione negli ambienti della facoltà di ingegneria civile e industriale dell’università di Roma “Sapienza”."Granting structure and identity to the environment is a vital capacity of all animals with movement." (Lynch, 1964)
It is precisely from this that the idea of the project proposed here is inspired, by the attempt to propose the territory that people dwell on a sheet, giving specific order to the elements; as it is the absence of loss and the ability to orient ourselves to give us a sense of balance and well-being. "The same word lost means in our language much more than simple geographical uncertainty: it brings with it shades of true tragedy. [...] One might object, that the human brain is wonderfully adaptable. [...] Still, even the sea has the sun and the stars, the winds, the currents, the birds and the color of the water without which the navigation would be Impossible." (Lynch, 1964) Cartography plays a fundamental role for all geographic data, that are data which have a spatial attribute as the main feature; The phenomena that can be described starting from their positioning are termed georeferenced. Cartography, therefore, deals with the storage (and representation) of georeferencing data; it aims to provide a knowledge of both local and general territory, to develop logic processes based on relationships and to serve as a base for planning, planning and management of the territory (Brovelli, 2000). It is in this context that the project is inserted in an attempt to provide a useful and powerful tool that allows a single user to navigate, in real time, in areas without GNSS coverage. The project proposes the use of an Open Source platform to support indoor navigation and shows an application in the environments of the Faculty of Civil and Industrial Engineering at the University of Rome "Sapienza"
New applications and opportunities of GNSS meteorology
Full text linkWater vapor content of the atmospheric low layer, up to
about 18 km, known as troposphere or neutral atmosphere,
affects GNSS (Global Navigation Satellite System) signals
by lowering their propagation velocities with respect to vacuum.
A diminished speed results in a time delay in the signal
propagation along the satellite-receiver path, that multiplied
by the vacuum speed of light adds an extra-distance
to the satellite-receiver geometrical one. This delay defines
a parameter which takes the name of Tropospheric Delay
(TD) and consists of an Hydrostatic (HD) and aWet (WD)
part. Anyway, if from the positioning point of view this delay
is just a systematic error to be removed, it puts forward
GNSS as a tool for the remote sensing of the troposphere
water vapor content.
The role of GNSS in meteorology is rapidly increasing; water
vapor plays a crucial role in atmospheric processes that
act over a wide range of temporal and spatial scales, from
global climate to micrometeorology [16] and GNSS data can
be extremely useful for the purpose of a multi-instrumental
investigation; indeed it was used to calibrate and validate
other instruments [26] or methodologies [87], but probably
one of the most impactful application is related to the assimilation
of GNSS data into the meteorological models [8]
[42] [19].
In this study, a global analysis of the role of the GPS data in
the field of meteorology was carried out. A focus was kept
on the assimilation of data in NWP Models, also according
to the cooperation with the Institute of Atmospheric Sciences
and Climate of National Research Council of Italy,
which included this work in the frame of a collaboration
with the Department of Italian Civil Protection.
The main aim of this thesis is to find parameters able to
support the analysis and forecast of intense meteorological
events.
To do this, a comparative analysis was carried out between
GPS outputs and other Precipitable Water Vapor (PWV)
measurement instruments; results show great consistency
between the data (St. Dev.1cm).
Another test was performed on the assimilation in NWP
Models, in particular RAMS Model; in this case it has been
found a noticeable impact (20-30% improvement) on ZTD
and IWV for short term forecast.
As for the Near Real Time (NRT) processing, results obtained
are encouraging with a St. Dev.< 1cm with respect
to post-processing (PP).
To sum up, results provide an overall assessment of the
data quality obtained through GPS post-processing and a
milestone for NRT processing, also in view of early warning
systems
Nowcasting extreme rain and extreme wind speed with machine learning techniques applied to different input datasets
Full text linkPredicting extreme weather events in a short time period and their developing in localized areas is a challenge. The nowcasting of severe and extreme weather events is an issue for air traffic management and control because it affects aviation safety, and determines delays and diversions. This work is part of a larger study devoted to nowcasting rain and wind speed in the area of Malpensa airport by merging different datasets. We use as reference the weather station of Novara to develop a nowcasting machine learning model which could be reusable in other locations. In this location we have the availability of ground-based weather sensors, a Global Navigation Satellite System (GNSS) receiver, a C-band radar and lightning detectors. Our analysis shows that the Long Short-Term Memory Encoder Decoder (LSTM E/D) approach is well suited for the nowcasting of meteo- rological variables. The predictions are based on 4 different datasets configurations providing rain and wind speed nowcast for 1 h with a time step of 10 min. The results are very promising with the extreme wind speed probability of detection higher than 90%, the false alarms lower than 2%, and a good performance in extreme rain detection for the first 30 min. The configuration using just weather stations and GNSS data in input provides excellent performances and should be preferred to the other ones, since it refers to the pre-convective envi- ronment, and thus can be adaptable to any weather conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
TWIGA project activities for the enhancement of heavy rainfall predictions in Africa: low-cost GNSS network deployment and NWP model parameterization
Full text linkMultivariate Multi-Step Convection Nowcasting with Deep Neural Networks: The Novara Case Study
No full textSevere weather events are constantly increasing over northern Italy impacting the air traffic of one of the major airports of Europe: Milano Malpensa. Monitoring and predicting extreme convection is very challenging especially when it develops locally in a short time range. This work is performed within two projects funded by the H2020 SESAR Programme, with the objective of nowcasting with high accuracy the strong weather events affecting the airport. We collected different types of data from 10 locations around the airport and developed an end-to-end nowcasting deep neural networks based model for each of these stations. We show in this paper the results that we obtained for Novara, the only station for which we have available weather stations, radar, GNSS and lightning
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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