1,720,964 research outputs found
Assessing the performance of a charge-while-driving system in urban arterial roads: insight from a microsimulation model
No full textThis study presents a method based on traffic microsimulation to support feasibility studies on charge-whiledriving (CWD) systems for fully electric vehicles in urban environments. The examined CWD solution is deployed by charging zones (CZs), which are installed before the stopping lines at signalised intersections. The opportunity to charge an electric vehicle en route is provided for almost stationary vehicle conditions, when it may be in queue for junction control requirements. The analysed scenario refers to a 2 km urban arterial with eight signalised intersections, where 10% of the traffic is assumed to be electric vehicles. CWD performance results are reported from the viewpoints of both driver and energy provider. The estimated stop time for electric vehicles at any section can vary and is often below 30 s. However, the entire stop time for a vehicle along the arterial is higher: ∼50% of the vehicles can charge in a range of 10-65 s. For the energy operator's viewpoint, a support analysis for the CZ location was performed by observing the charging opportunities at various sections. Finally, the total electric power provided for the entire system is estimate
Traffic Modeling of a Cooperative Charge While Driving System in a Freight Transport Scenario
Full text linkThe aim of this paper is to present a research study on a traffic model developed for analysing the performance of the wireless inductive systems for charging while driving (CWD) fully electric vehicles (FEVs) from both traffic and energy points of view. The design assumptions of the developed traffic model are aimed to simulate in particular a freight distribution service in a fully cooperative traffic environment. In this case, the CWD service could be used to guarantee the minimum state of charge (SOC) of the batteries at the arrival to the depot that allows the vehicles to shortly start with further activities. In this way, the fleet manager could avoid wasting time for the stationary recharge, thus increasing the level of service of the freight distribution. The CWD system is applied to a multilane ring road with several intermediate on-ramp entrances, where the slowest lane is reserved for the charging activities, when authorized vehicles are present. A specific traffic model has been developed and implemented adopting a mesoscopic approach, where vehicle energy needs and charging opportunities affect drivers' behavior. Overtaking maneuvers, as well as new entries in the CWD lane of vehicles which need to charge, have been modeled by taking into account a fully cooperative driving system among vehicles which manages an adequate gap between consecutive vehicles. Finally, a speed control strategy in which vehicles can be delayed to create an empty time-space slot in the CWD lane, is simulated at a defined node. This type of control, though is simulated to allow extraordinary maintenance operations, which may require a free charging zone for a given time slot, could also be applied to support merging maneuvers for on ramp vehicle
Dynamic charging-while-driving systems for freight delivery services with electric vehicles: Traffic and energy modelling
Full text linkThis paper presents a research on traffic modelling developed for assessing traffic and energy performance of electric systems installed along roads for dynamic charging-while-driving (CWD) of fully electric vehicles (FEVs). The logic adopted by the developed traffic model is derived from a particular simulation scenario of electric charging: a freight distribution service operated using medium-sized vans. In this case, the CWD service is used to recover the state of charge of the FEV batteries to shortly start with further activities after arrival at the depot. The CWD system is assumed to be implemented in a multilane ring road with several intermediate on-ramp entrances, where the slowest lane is reserved for the dynamic charging of authorized electric vehicles. A specific traffic model is developed and implemented based on a mesoscopic approach, where energy requirements and charging opportunities affect driving and traffic behaviours. Overtaking manoeuvres as well as new entries in the CWD lane of vehicles that need to charge are modelled according to a cooperative driving system, which manages adequate time gaps between consecutive vehicles. Finally, a speed control strategy is simulated at a defined node to create an empty time-space slot in the CWD lane, by delaying the arriving vehicles. This simulated control, implemented to allow maintenance operations for CWD that may require clearing a charging zone for a short time slot, could also be applied to facilitate on-ramp merging manoeuvres
Dynamic charging systems for electric vehicles: simulation for the daily energy estimation on motorways
No full textThis study presents an application for motorway scenarios of charge while driving (CWD) also known as dynamic charging systems for fully electric vehicles (FEVs). This charging modality "in motion" strongly relies on intelligent transport systems (ITS) solutions, because it can be feasible and accepted by users if automatic identification, positioning and communications technologies are applied. The investigated case is a motorway with three lanes where the right-hand lane is reserved for charging at defined speeds for FEVs. The input traffic flow for the motorway is simulated according to an hourly time profile along the day. To generalise the simulation for various traffic levels, the traffic flow for any time interval is estimated on the base of the traffic density, known from available data. The FEVs are only a part of the whole traffic and their input traffic is estimated as a percentage. The principal aim of this study is to estimate the daily energy provided to electric vehicles by the CWD system, which can be used, together with other data if available, to build possible business models and help stakeholders configure charging services. For this reason, the total energy provided is estimated by simulation for different scenarios
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
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