1. Determining the Aethalometer multiple scattering enhancement factor C from the filter loading parameterLuca Ferrero, Niccolò Losi, Martin Rigler, Asta Gregorič, C. Colombi, L. D'Angelo, E. Cuccia, A. M. Cefalì, I. Gini, A. Doldi, 2024, izvirni znanstveni članek Opis: Light-absorbing aerosols heat the atmosphere; an accurate quantification of their absorption coefficient is mandatory. However, standard reference instruments (CAPS, MAAP, PAX, PTAAM) are not always available at each measuring site around the world.
By integrating all previous published studies concerning the Aethalometers, the AE33 filter loading parameter, provided by the dual-spot algorithm, were used to determine the multiple scattering enhancement factor from the Aethalometer itself (hereinafter CAE) on an yearly and a monthly basis. The method was developed in Milan, where Aethalometer measurements were compared with MAAP data; the comparison showed a good agreement in terms of equivalent black carbon (R2 = 0.93; slope = 1.02 and a negligible intercept = 0.12 μg m−3) leading to a yearly experimental multiple scattering enhancement factor of 2.51 ± 0.04 (hereinafter CMAAP). On a yearly time base the CAE values obtained using the new approach was 2.52 ± 0.01, corresponding to the experimental one (CMAAP). Considering the seasonal behavior, higher experimental CMAAP and computed CAE values were found in summer (2.83 ± 0.12) whereas, the lower ones in winter/early-spring (2.37 ± 0.03), in agreement with the single scattering albedo behavior in the Po Valley.
Overall, the agreement between the experimental CMAAP and CAE showed a root mean squared error (RMSE) of just 0.038 on the CMAAP prediction, characterized by a slope close to 1 (1.001 ± 0.178), a negligible intercept (−0.002 ± 0.455) and a high degree of correlation (R2 = 0.955). From an environmental point of view, the application of a dynamic (space/time) determination of CAE increases the accuracy of the aerosol heating rate (compared to applying a fixed C value) up to 16 % solely in Milan, and to 114 % when applied in the Arctic at 80°N.
Ključne besede: aethalometer, C factor, loading parameter, MAAP, heating rate
Objavljeno v RUNG: 02.02.2024; Ogledov: 461; Prenosov: 4
 Celotno besedilo (3,18 MB) |
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3. A cellular network database for fingerprint positioning systemsDonatella Gubiani, Paolo Gallo, Andrea Viel, Andrea Dalla Torre, Angelo Montanari, 2019, objavljeni znanstveni prispevek na konferenci Opis: Besides being a fundamental infrastructure for communication, cellular networks are increasingly exploited for positioning via signal fingerprinting.
Here, we focus on cellular signal fingerprinting, where an accurate and comprehensive knowledge of the network is fundamental.
We propose an original multilevel database for cellular networks, which can be automatically updated with new fingerprint measurements and makes it possible to execute a number of meaningful analyses. In particular, it allows one to monitor the distribution of cellular networks over countries, to determine the density of cells in different areas, and to detect inconsistencies in fingerprint observations.
Ključne besede: Cellular network, Signal fingerprinting, Multilevel database, Data analysis
Objavljeno v RUNG: 17.09.2019; Ogledov: 3371; Prenosov: 0
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4. A map-matching algorithm dealing with sparse cellular fingerprint observationsAndrea Dalla Torre, Paolo Gallo, Donatella Gubiani, Chris Marshall, Angelo Montanari, Federico Pittino, Andrea Viel, 2019, izvirni znanstveni članek Opis: The widespread availability of mobile communication makes mobile devices a resource for the collection of data about mobile infrastructures and user mobility. In these contexts, the problem of reconstructing the most likely trajectory of a device on the road network on the basis of the sequence of observed locations (map-matching problem) turns out to be particularly relevant. Different contributions have demonstrated that the reconstruction of the trajectory of a device with good accuracy is technically feasible even when only a sparse set of GNSS positions is available. In this paper, we face the problem of coping with sparse sequences of cellular fingerprints. Compared to GNSS positions, cellular fingerprints provide coarser spatial information, but they work even when a device is missing GNSS positions or is operating in an energy saving mode. We devise a new map-matching algorithm, that exploits the well-known Hidden Markov Model and Random Forests to successfully deal with noisy and sparse cellular observations. The performance of the proposed solution has been tested over a medium-sized Italian city urban environment by varying both the sampling of the observations and the density of the fingerprint map as well as by including some GPS positions into the sequence of fingerprint observations.
Ključne besede: Map-matching algorithm, trajectory, cellular fingerprint, Hidden Markov Model
Objavljeno v RUNG: 11.06.2019; Ogledov: 3343; Prenosov: 97
Celotno besedilo (3,93 MB) |
5. Map matching with sparse cellular fingerprint observationsAndrea Viel, Donatella Gubiani, Paolo Gallo, Angelo Montanari, Andrea Dalla Torre, Federico Pittino, Chris Marshall, 2018, objavljeni znanstveni prispevek na konferenci Ključne besede: map matching, fingerprint, trajectories
Objavljeno v RUNG: 09.12.2018; Ogledov: 3650; Prenosov: 0
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6. Dealing with network changes in cellular fingerprint positioning systemsAndrea Viel, Paolo Gallo, Angelo Montanari, Donatella Gubiani, Andrea Dalla Torre, Federico Pittino, Chris Marshall, 2017, objavljeni znanstveni prispevek na konferenci Opis: Besides being a fundamental infrastructure for communication, cellular networks are exploited for positioning through signal fingerprinting. Maintaining the fingerprint database consistent and up-to-date is a challenging task in many fingerprint positioning systems, e.g., in those populated by a crowd-sourcing effort. To this end, detecting and tracking the changes in the configurations of cellular networks over time is recognized as a relevant problem. In this paper, we show that to cope with this problem we can successfully exploit information provided by Timing Advance (TA). As a by-product, we prove that TA can improve the fingerprint candidate selection phase, reducing the number of fingerprints to provide as input to positioning algorithms. The effectiveness of the proposed improvements has been tested on a fingerprint positioning system with a large fingerprint dataset collected over a period of 2 years.
Ključne besede: fingerprint positioning systems, cellular communication networks, network changes
Objavljeno v RUNG: 13.06.2018; Ogledov: 3935; Prenosov: 0
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7. New strategy for magnetic gas sensingRoberta Ciprian, Piero Torelli, Angelo Giglia, B Gobaut, Barbara Ressel, Janez Štupar, Matija Stupar, Antonio Caretta, Giovanni De Ninno, Tommaso Pincelli, Barbara Casarin, Ganesh Adhikari, G Sberviglieri, C Baratto, Marco Malvestuto, 2016, izvirni znanstveni članek Ključne besede: hybrid nanostructures, sensor, absorption spectroscopy
Objavljeno v RUNG: 05.02.2018; Ogledov: 4014; Prenosov: 0
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