1,720,961 research outputs found
Optimal allocation of electric vehicle charging stations in a highway network: Part 1. Methodology and test application
No full textGradual electrification is widely considered as a feasible strategy for reducing the oil dependency and CO2 emissions of road transportation. In chase of these aims increasing importance has been attributed to Electric Vehicles (EVs). Although the European Commission has strongly supported sustainable mobility initiatives in recent years, with the purpose of decarbonizing road transport and mitigating urban air pollution, results are below expectations. Among the initiatives that can be implemented the most important is certainly the use of electric vehicles on a large scale but it will be necessary, in parallel, to plan an appropriate system of infrastructures that will be able to support the expansion. In this paper a methodology to provide optimal locations of electric vehicle infrastructures in a highway network is proposed. The procedure can also be used to support the implementation of the DAFI (Directive on the Deployment of Alternative Fuels Infrastructure). The goal is to estimate the basic number of charging stations and determine their correct allocation on the road network by analyzing the supply and demand and considering the psychological component of the driver. In Part 1, the subject of this research article, a model is presented to detect how many charging infrastructures are required within the service areas and to identify their location. After the description of the solution algorithm, a test application is performed in order to assess model and technique. With the aim of analysing a high-level system, the model will be used, in Part 2 of the work, to calculate and distribute the charging point on the Italian case study
Electric vehicle charging infrastructure planning in a road network
No full textThe implementation of a charging infrastructure network is the necessary prerequisite for the diffusion of Electric Vehicles (EVs). In this paper a methodology to calculate the required number of charging stations for EVs and to set their position in a road network is proposed. The aim is to planning the distribution of services area to host charging infrastructures. Using the demand (the flow of EVs) and the supply (the road network where they will be positioned) through a two-level model were the locations initially identified (first level) and thereafter the number of charging stations for each service area (second level) evaluated. The paper deals with the intersection of three main topics: the vehicle technologies (engine and battery pack specifications), the charging station characteristics and the EVs flow. After verifying the model and the solution procedure on a test road network, the methodology is applied in a high dimension case, considering the Italian highway network
Optimal allocation of electric vehicle charging stations in a highway network: Part 2. The Italian case study
No full textAfter introducing the methodology in the first part of the article, in this Part 2 the algorithm is applied to calculate and identify the optimal positions of the charging stations for electric vehicles in the Italian highway network. The main objective is to map the infrastructural needs of the country using the information acquired from the most recent data base. The results can also be used to facilitate the application of the Directive on the Deployment of Alternative Fuels Infrastructure. In the paper the market for electric vehicles circulating in Italy is initially analyzed and, after applying an appropriate filtering, the algorithm input variables relating to the vehicle system (vehicle autonomy and energy of the battery pack) are identified. For this purpose, both the registration data and the technical characteristics provided by the manufacturers have been used. Subsequently the road system (the flow of vehicles with related indicators), the infrastructures (the number of sockets and the charging station power), and driver behavior (range anxiety) are considered. The results show a map of candidate points to allocate the charging stations divided by region. After having sized and placed the charging infrastructures with different planning scenario, some future projections are also introduced
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
Service trips and returnable packaging: a case study via electric vehicles in Rome
No full textUrban freight transport represents 15-20% of vehicular traffic, generating more than 20% of greenhouse gases (GHG) emissions from transport. Given its complexities, which differentiate it from passenger transport, it is necessary to address the opportunities for technological innovation on this topic in a distinct manner. The new generations of electric vehicles offer the opportunity to improve the environmental impact, but the use of electric vehicles cannot represent the only solution to all challenges related to urban freight transport in urban areas, which include, for example, congestion. Delivery parking is often limited and new European regulations relating to packaging collection require supply chain monitoring. The paper proposes the use of new distribution models to evaluate the impacts deriving from the use of electric vehicles for urban transportation. Through a case study applied to the city of Rome, which also includes the supply of an installation service, the polluting emissions of a light commercial vehicle are calculated, including the energy consumption if the vehicle is battery powered and the consequent time saving resulting from the adoption of micro hubs and cargo bikes for packaging collection. The results encourage a multidisciplinary approach to the topic of freight transport with electric vehicles as a planning tool for local authorities responsible for urban planning
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
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