1,720,957 research outputs found
EVALUATION OF MECHANICAL CHARACTERISTICS BY DEFLECTION MEASUREMENT ON RIGID OR COMPOSITE PAVEMENT
No full textDevelopment of a predictive model for the temperature distribution in a flexible pavement based on measurements of a monitored road section
No full textThe elastic modulus of an asphalt concrete pavement is strongly influenced by the temperature of the layer. This is due to the rheological behaviour of the binder present in asphalt concrete layer. For this reason it has a great importance knowing the thermal state of the layer for comparing the values of the elastic modulus of pavements in different climatic conditions. In the case of deflection measurements this is especially necessary. Basing on these considerations, a predictive model of the temperatures inside the pavement has been developed. It uses as input the temperature at the surface as is recorded during FWD tests. The model is founded on a database of temperatures measured at surface and at different depths (10, 15, 20, 30 cm) of an asphalt concrete pavement during three years
Assessment of Design Consistency for Two-Lane Rural Highways with Low Tortuosity Alignment
Full text linkOne technique employed to enhance road safety involves assessing the alignment’s consistency. A prevalent measure of consistency is evaluating speed variations along the alignment. A key consideration in this assessment is determining the speed upon which the road alignment should be based. This research reveals that on two-lane rural highways with low tortuosity alignments, operating speeds on horizontal curves and tangents consistently exceeded not only the design speeds but also the maximum permissible design speed for the road category. Consequently, using the design speed to assess consistency on these roads is deemed impractical, and utilizing operating speed poses challenges due to speeds exceeding the maximum permissible limit. The objectives of this paper are twofold: to explore the relationship between design consistency and safety levels on two-lane rural highways with low tortuosity alignments (which have been insufficiently covered in research) and to propose speed-control measures to limit the maximum operating speed to the maximum permissible speed. The study findings suggest that on roads with a low tortuosity alignment, operating speeds depend much more on the general characteristics of the alignment (evaluated in the operating speed models through the desired speed). Further, assessing speed consistency is feasible only with a rigorous control of the maximum operating speed (desired speed). Additionally, a specific type of speed control is recommended, achieved by limiting the curvature change rate (CCR) of the road section based on the desired speed (environmental speed), whose evaluation becomes a crucial factor
Gli Indicatori di Prestazione a Livello di Rete, Indicatori di prestazione per singolo stakeholder
No full textL’individuazione degli investimenti da fare per il mantenimento ed il miglioramento delle reti di trasporto è un problema di non facile soluzione e che investe vari livelli decisionali.
Il Governo di un Paese o di una Regione deve operare le scelte per soddisfare la domanda di mobilità delle persone e delle merci considerando tutte le modalità di trasporto, stradale, ferroviaria, aerea e marittima. Il patrimonio da considerare comprende tutte le reti, le stazioni ferroviarie, gli aeroporti, i porti.
Un Ente gestore di una rete viaria, invece, rivolge ovviamente la sua attività alle sole strade e la limita generalmente alla loro conservazione e miglioramento. Il patrimonio consisterà allora nelle infrastrutture stradali di sua competenza, a cui si aggiungono le risorse umane e le attrezzature necessarie per il suo funzionamento.
Qualora l’Ente gestore individui la necessità di interventi che modifichino il suo patrimonio, per esempio nuovi assi stradali, raddoppi in sede o modifiche di tracciato che impegnino cospicui investimenti, li segnalerà agli organi di governo che dovranno tenerne conto nella programmazione degli interventi di loro competenza.
Una gestione efficace del patrimonio richiede che l’allocazione delle risorse disponibili sia effettuata in una visione unitaria di tutte le componenti al fine di ottimizzare la qualità della rete con riferimento a determinati obiettivi. Il tener conto però di tutte le componenti è nella realtà un approccio molto complesso che si basa spesso su valutazioni approssimative e spesso solo intuitive, mentre oggi si comincia a dare una base scientifica alla sola componente “infrastruttura”. Le metodologie ed i criteri esposti nel presente quaderno si limitano a tale componente e di conseguenza il “patrimonio stradale” è inteso qui solo come infrastruttura. Nel quaderno vengono poi anche richiamati i sistemi di gestione parziale che tuttora vengono utilizzati da alcuni enti e che interessano le pavimentazioni, i ponti, le gallerie.
Per quanto concerne gli obiettivi, a cui si è fatto cenno, questi sono stati individuati nella sostenibilità ambientale (rumore, vibrazioni, qualità di aria ed acqua, ecc.), nella fruibilità (tempo di viaggio, affidabilità, informazioni , accessibilità, ecc.), nella sicurezza (tassi di incidentalità, costo per incidente, ecc.), nel valore del patrimonio (conservazione e miglioramento, efficienza della gestione) e nel miglioramento sociale ed economico (incremento e ritorno degli investimenti, itinerari per soccorsi, ecc.).
Nel quaderno sono individuati i soggetti (stakeholders) coinvolti nel processo di gestione: le Amministrazioni proprietarie, i Gestori, gli Utenti e le Comunità. In relazione ai vari livelli di azione (dal livello 1, di progetto, in cui le prestazioni sono rappresentate da parametri di dettaglio, al livello 5, di pianificazione strategica, in cui le prestazioni sono rappresentate da indicatori sinottici), nel quaderno si focalizza l’attenzione sui livelli medio-alti, cioè alla gestione a livello di rete
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
- …
