1,720,965 research outputs found
Data-driven geological multi-hazard risk analysis at urban scale
No full textThis research work explores the intricate domain of geological multi-hazard risk assessment in urban environments, with a particular focus on the Municipality of Rome, Italy. By leveraging data-driven methodologies, advanced Machine Learning techniques, and open-access data, this study addresses the challenges posed by ground instability hazards, including landslides, subsidence, and sinkholes. The research offers valuable insights, innovative models, and practical applications, contributing to urban resilience enhancement and risk mitigation.
As the global trend of urbanization continues to transform landscapes and increase population concentration in cities, the understanding and management of geological hazards in urban areas have never been more critical. This research encompasses three key articles published within the thesis, to delve into geological multi-hazard risk analysis in the urban context.
In Chapter 2, we tackle the challenge of integrating fragmented, incomplete, and often unreliable data sources for landslide hazard assessment. Recognizing the crucial role of hazard evaluation in risk mitigation policies, we focused on making the most of available data. The methods employed include landslide inventory review, boosting the training dataset, and optimizing Machine Learning-based susceptibility analysis. The research explores temporal recurrence by analysing multi-temporal landslide inventories and historical rainfall databases, offering valuable insights into hazard probability. The integration of spatial and temporal attributes led to the creation of Rome's first large-scale landslide hazard product. This product, designed for statutory purposes, represents a significant milestone in improving the resilience of urban areas.
Chapter 3 delves into the world of Machine Learning techniques for landslide susceptibility mapping, emphasizing the significance of data quality. The study compared various models, with the ExtraTreesClassifier emerging as the most reliable choice. However, recognizing the rarity of high-quality, site-specific landslide inventories, the research examines the reliability of open-source landslide susceptibility maps at different spatial scales. By conducting a thorough statistical and spatial analysis, the research highlights the impact of mapping unit and analysis scale on prediction accuracy. Furthermore, the fusion of multiple low-resolution susceptibility maps is introduced, offering a promising approach to overcome data limitations. This milestone not only improves our understanding of landslide susceptibility mapping but also provides practical tools for large-scale assessments in urban environments.
The development of a novel model for multi-risk assessment takes centre stage in Chapter 4. The model's goal is to support decision-makers and risk managers in prioritizing buildings exposed to ground instability hazards, including landslides, subsidence, and sinkholes. By integrating spatial hazard assessments, satellite interferometric data, building characteristics, and asset market values, the model calculates a multi-risk score, enabling the ranking of urban buildings. The research offers a detailed explanation of how each dataset contributes to the overall risk assessment, from spatial hazard to potential economic damage and activity rates. The data harmonization process leads to a practical, semi-quantitative approach for multi-risk assessment, fostering a more proactive stance in mitigating ground instability hazards.
This Ph.D. work could bring relevant insights for geological multi-hazard risk assessment and urban resilience. Its findings lay the foundation for further research, fostering safer, more resilient cities worldwide
Combining ground based remote sensing tools for rockfalls assessment and monitoring. The Poggio Baldi landslide natural laboratory
Full text linkNowadays the use of remote monitoring sensors is a standard practice in landslide characterization and monitoring. In the last decades, technologies such as LiDAR, terrestrial and satellite SAR interferometry (InSAR) and photogrammetry demonstrated a great potential for rock slope assessment while limited studies and applications are still available for ArcSAR Interferometry, Gigapixel imaging and Acoustic sensing. Taking advantage of the facilities located at the Poggio Baldi Landslide Natural Laboratory, an intensive monitoring campaign was carried out on May 2019 using simultaneously the HYDRA-G ArcSAR for radar monitoring, the Gigapan robotic system equipped with a DSLR camera for photo-monitoring purposes and the DUO Smart Noise Monitor for acoustic measurements. The aim of this study was to evaluate the potential of each monitoring sensor and to investigate the ongoing gravitational processes at the Poggio Baldi landslide. Analysis of multi-temporal Gigapixel-images revealed the occurrence of 84 failures of various sizes between 14–17 May 2019. This allowed us to understand the short-term evolution of the rock cliff that is characterized by several impulsive rockfall events and continuous debris production. Radar displacement maps revealed a constant movement of the debris talus at the toe of the main rock scarp, while acoustic records proved the capability of this technique to identify rockfall events as well as their spectral content in a narrow range of frequencies between 200 Hz to 1000 Hz. This work demonstrates the great potential of the combined use of a variety of remote sensors to achieve high spatial and temporal resolution data in the field of landslide characterization and monitoring
Contribution of High-Resolution Virtual Outcrop Models for the Definition of Rockfall Activity and Associated Hazard Modelling
Full text linkThe increased accessibility of drone technology and structure from motion 3D scene reconstruction have transformed the approach for mapping inaccessible slopes undergoing active rockfalls and generating virtual outcrop models (VOM). The Poggio Baldi landslide (Central Italy) and its natural laboratory offers the possibility to monitor and characterise the slope to define a workflow for rockfall hazard analysis. In this study, the analysis of multitemporal VOM (2016–2019) informed a rockfall trajectory analysis that was carried out with a physical-characteristic-based GIS model. The rockfall scenarios were reconstructed and then tested based on the remote sensing observations of the rock mass characteristics of both the main scarp and the rockfall fragment inventory deposited on the slope. The highest concentration of trajectory endpoints occurred at the very top of the debris talus, which was constrained by a narrow channel, while longer horizontal travel distances were allowed on the lower portion of the slope. To further improve the understanding of the Poggio Baldi landslide, a time-independent rockfall hazard analysis aiming to define the potential runout associated with several rock block volumetric classes is a critical component to any subsequent risk analysis in similar mountainous settings featuring marly–arenaceous multilayer sedimentary successions and reactivated main landslide scarps
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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