1,720,977 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
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
A GIS tool for mapping dam-break flood hazards in Italy
Full text linkMapping the delineation of areas that are flooded due to water control infrastructure failure is a critical issue. Practical difficulties often present challenges to the accurate and effective analysis of dam-break hazard areas. Such studies are expensive, lengthy, and require large volumes of incoming data and refined technical skills. The creation of cost-efficient geospatial tools provides rapid and inexpensive estimates of instantaneous dam-break (due to structural failure) flooded areas that complement, but do not replace, the results of hydrodynamic simulations. The current study implements a Geographic Information System (GIS) based method that can provide useful information regarding the delineation of dam-break flood-prone areas in both data-scarce environments and transboundary regions, in the absence of detailed studies. Moreover, the proposed tool enables, without advanced technical skills, the analysis of a wide number of case studies that support the prioritization of interventions, or, in emergency situations, the simulation of numerous initial hypotheses (e.g., the modification of initial water level/volume in the case of limited dam functionality), without incurring high computational time. The proposed model is based on the commonly available data for masonry dams, i.e., dam geometry (e.g., reservoir capacity, dam height, and crest length), and a Digital Elevation Model. The model allows for rapid and cost-effective dam-break hazard mapping by evaluating three components: (i) the dam-failure discharge hydrograph, (ii) the propagation of the flood, and (iii) the delineation of flood-prone areas. The tool exhibited high accuracy and reliability in the identification of hypothetical dam-break flood-prone areas when compared to the results of traditional hydrodynamic approaches, as applied to a dam in Basilicata (Southern Italy). In particular, the over- and under-estimation rates of the proposed tool, for the San Giuliano dam, Basilicata, were evaluated by comparing its outputs with flood inundation maps that were obtained by two traditional methods whil using a one-dimensional and a two-dimensional propagation model, resulting in a specificity value of roughly 90%. These results confirm that most parts of the flood map were correctly classified as flooded by the proposed GIS model. A sensitivity value of over 75% confirms that several zones were also correctly identified as non-flooded. Moreover, the overall effectiveness and reliability of the proposed model were evaluated, for the Gleno Dam (located in the Central Italian Alps), by comparing the results of literature studies concerning the application of monodimensional numerical models and the extent of the flooded area reconstructed by the available historical information, obtaining an accuracy of around 94%. Finally, the computational efficiency of the proposed tool was tested on a demonstrative application of 250 Italian arch and gravity dams. The results, when carried out using a PC, Pentium Intel Core i5 Processor CPU 3.2 GHz, 8 GB RAM, required about 73 min, showing the potential of such a tool applied to dam-break flood mapping for a large number of dams
LA STIMA DELLA PERICOLOSITÀ IDRAULICA PER EVENTI PLUVIOMETRICI ESTREMI IN AREE URBANE: IL RUOLO DELLA MODELLAZIONE IDRODINAMICA
No full textLe alluvioni rappresentano un problema estremamente diffuso sul territorio nazionale. L'urbanizzazione incontrollata, ovvero una copertura permanente del terreno e del relativo suolo con materiale artificiale non permeabile, contribuisce ad alterare il regime delle acque superficiali e sotterranee. Infatti, la ridotta capacità delle aree urbane di assorbire le acque di precipitazione per infiltrazione, comporta un notevole aumento in termini di volumi, portate e velocità del deflusso idrico superficiale. Tutto ciò, unito all'aumento dell'intensità e della frequenza di eventi estremi di precipitazione, attribuiti ai processi di cambiamento climatici, aggrava le ripercussioni degli stessi eventi.
In questo contesto è rappresentativo il caso di studio della città di Matera, la quale nel corso degli ultimi anni è stata interessata più volte da eventi di precipitazione intensa che hanno causato importanti disagi per la popolazione e diversi danni. L'ultimo evento in ordine cronologico risale allo scorso novembre, quando un fiume di acqua e fango è penetrato nelle abitazioni allagando i piani più bassi ed ha interrotto in più tratti la circolazione. Non avendo, per il caso di studio, a disposizione dati rilevati in-situ rispetto ai quali validare le simulazioni idrodinamiche, si sono confrontati i risultati delle simulazioni condotte con i modelli idrodinamici bidimensionali FLORA-2D (Cantisani et al., 2014) e LISFLOOD-FP (Bates, 2007) con la finalità di ricercare procedure operative e strumenti per una gestione delle inondazioni per scopi sia di previsione e allertamento che relativi alla pianificazione territoriale (ex ante). Il modello FLORA-2D, che trascura i termini convettivi delle equazioni delle acque basse, è stato inizialmente sviluppato con lo scopo di simulare la propagazione delle piene in aree pianeggianti con la possibilità di tenere conto della variazione spazio-temporale della scabrezza in base alle caratteristiche della vegetazione e, successivamente, è stato modificato, inserendo la possibilità di ricevere in input ietogrammi di pioggia efficace variabili spazialmente con il tipo di suolo, al fine di consentire anche la simulazione di allagamenti in ambito urbano generati da precipitazioni estreme. Invece, il modello LISFLOOD-FP ha la peculiarità di poter scegliere alternativamente diversi schemi numerici, che si differenziano in base ai termini delle equazioni delle acque basse considerati, che rendono la sua applicazione flessibile in base ai dati disponibili, ed agli scopi dello studio. Nel presente lavoro sono stati testati, sul caso di studio di Matera, tre schemi numerici: lo schema Acceleration che trascura l'accelerazione convettiva, il Flow-Limited che oltre a quella convettiva trascura l'accelerazione locale, e, infine, lo schema Roe, che tratta le equazioni complete.
Le simulazioni con un modello idraulico bidimensionale sono importanti in ambito urbano ogni qual volta il tempo di ritorno della precipitazione supera quello di progettazione della fognatura. Infatti, spesso i sistemi di drenaggio urbani vanno in crisi in occasione di eventi di precipitazione intensi per diverse cause, quali: un progetto originario per tempi di ritorno non particolarmente elevati (es. Tr=10 anni), l’aggiunta di nuovi rami di rete senza un suo adeguamento complessivo, l’incremento delle portate dovuto all'impermeabilizzazione del suolo o ai cambiamenti climatici. In tutti i casi di insufficienza della rete di drenaggio, l’uso di un modello idrodinamico bidimensionale consente di valutare sia il perimetro delle aree allagabili che le caratteristiche dell’allagamento quali le altezze d’acqua e le velocita
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
- …
