1,720,964 research outputs found
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
Rainfall induced-landslides and man-made landforms mapping for underground utility networks management in a Mediterranean metropolitan area (Genoa, Northwest Italy)
No full textExtreme precipitation has become increasingly frequent in the last years in Liguria, a hilly and
mountainous region in Nortwest Italy. In particular, the Genoa metropolitan area is internationally
known for rainfall ground effects: from the beginning of this millennium four intense flash floods
have been recorded and as many rainfall-induced landslide periods with significant impacts in
roads, buildings and underground utility networks.
These phenomena are also related with more than a century of urbanization that has completely
changed landforms and increased the vulnerability of the area.
The research consists of preliminary study based on the production of three different maps:
Landslide inventory map, Landslide susceptibility zoning map and a preliminary Man-made
landform map that could help to describe better the Urban Geomorphology of Genoa
metropolitan area, characterized by isolated and spread houses laying on terraced slopes mixed
with high density urban area with aged decametric retaining walls.
On site monitoring, satellite interferometric data and historical maps were used to support the
production of cartography work.
In a second step, the above maps were associated with underground utility networks (water and
energy) categorized by age, diameter and material to know the potential failure risks induced both
by geomorphological and structural factors.
Thanks to this research underground assets management is expected to be more efficient,
determining priorities for actions in areas with higher risk
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
Effects of urbanization on river morphology in a Mediterranean coastal city (Genova, Italy)
No full textFrom the geomorphological point of view, urbanization changes fluvial systems more drastically than any other single human activity. Its impact on rivers is of interest as it results in serious issues concerning geomorphic instability, ecosystem service reduction, and geo-hydrological risk increase. The present study provides a quantitative and qualitative assessment of landscape changes driven by urbanization, which occurred from the mid-19th century to the present day along the lower reaches of the Bisagno and Polcevera rivers and their tributaries in the Mediterranean coastal city of Genova (NW Italy). The bankfull channel morphological adjustments, the minor hydrographic network disappearance, the land use and land cover changes, and the current physical accessibility of river margins were investigated. This work is based on collection and review of historical data, photograph interpretation, GIS analysis, and field surveys.
Urbanization essentially occurred between the mid-19th century and the late 1930s. The bankfull channel of the Bisagno and Polcevera rivers experienced large narrowing associated with widespread establishment of channelization structures. The minor hydrographic network essentially disappeared underground. After the 1930s, further minor anthropogenic interventions were implemented to accommodate urban expansion and consolidate channelization works; however, the overall geomorphological setting remained unchanged. The geomorphological evolution of the Bisagno and Polcevera rivers followed three different phases associated with the urban expansion process. Nowadays, the study area is completely urbanized, the fluvial stems flowing through the valley floor are totally disconnected from their adjacent areas, the main
rivers show a relevant geomorphological stability induced by anthropogenic pressures, and the accessibility of river margins for people is rather limited. The outcomes from this study represent an essential knowledge base for technicians and policymakers to plan urban development and inform effective and sustainable management measures. Moreover, they provide insights into the medium- and short-term morphological evolution of urban rivers
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
Coupling historical maps and Lidar data to recognize man-made landforms in urban areas
No full textIn the last years there is growing interest on urban geomorphology both for the links with
landscape planning and for its historical, cultural and scientific interest.
The identification of landforms in urban contexts is particularly difficult due to the progressive
stratification of urban phases: the foundation of cities in the Mediterranean area dates back to
ancient times and their growth in size is generally significant from the Middle Ages. This makes it
frequent to find landforms which date back to more than 1000 years ago: they can be new, manmade
landforms or modifications of natural ones, particularly coastal or fluvial features. Land
modifications are particularly significant in the last 2 centuries, notably in the second half of the
C19th and in the second half of the C20th, two periods identified as the potential start of the
Anthropocene.
Anthropogenic terrain features are generally due to excavation and fill: unlike natural landforms
which are generally identifiable through field surveys, the former require field observations,
cartographical comparisons, multitemporal comparison of topographical views and historical
photographs, geognostic investigations and geophysical surveys.
This research presents the results of a multitemporal analysis of the city of Genoa carried out by
superimposing data from nineteenth-century historical cartography and topographical data from
Remote Sensing. The 1:2.000 scale map of Ignazio Porro, dating back to the first half of the C19th,
has been digitalised on Lidar images from 2019 and with 1 m resolution, provided by Genoa
Municipality. This methodology, developed with QGIS, has been applied on 5 sample areas
particularly significant for their anthropogenic modifications: the area around Sant’Agata bridge in
Val Bisagno, the area of Morandi Bridge in Val Polcevera, the road called Circonvallazione a Monte,
the Promontory of the Lighthouse and the Via Digione area. Through the overlaying of
multitemporal cartographies it was possible to identify and quantify with great precision
excavation, landfill and mixed areas, allowing the identification of the most significant
anthropogenic landforms. The obtained results have been validated through direct observations
and supported by data from the geognostic regional database, revealing the potential of this
approach for other urban areas
A numerical Approach to design and develop freestanding porous structures through cold spray multi-material deposition
Full text linkCold spray is a solid-state particle deposition technique with a wide range of applications for coating, repair and additive manufacturing. Cold spray parameters are normally tuned to obtain deposits with minimal porosity and thus highest strength. However, there are specific applications such as biomedical prostheses, heat sinks and energy absorbing products, where a higher exposed surface area can lead to enhanced performance, rendering porosity a desirable feature. Few recent studies have experimentally evaluated the potential of cold spray technology for obtaining porous deposits. To enhance the efficiency of these approaches, here we developed a detailed numerical framework that can determine the topological and mechanical features of cold spray porous deposits. A series of combined Eulerian-Lagrangian finite element models were developed considering a multi-material feedstock, one constituent of which served as a porogen. Different powder blends of pure Ti mixed with either Al or Cu, as the sacrificial powder, with varying volumetric fractions were analysed. A novel post-processing approach was developed to remove the sacrificial powder and extract distinct characteristic indicators from the simulations' output; these indices include porosity and structural connectivity of the remaining Ti structure. Equivalent plastic strain was considered as an index to assess the strength of the resultant deposit. The obtained data regarding particle deformation were in agreement with preliminary experimental tests. The numerical results revealed that Ti-Cu combinations can yield deposits with higher Ti particle deformation compared to the Ti-Al blend and hence, lead to a better inter-particle bonding. This study presents a robust numerical approach for selection of cold spray process parameters towards obtaining coatings and freestanding porous metal parts with modulated porosity, connectivity and strength
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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