1,720,959 research outputs found
A business-leisure traveller goes to Valencia: Fuel, CO2, time and cost
No full textTourism is a fast-growing key industry, which provides an economic rationale for governments to stimulate it. The more it grows, the higher the negative environmental effects and the more the use of space, resources, pollution and travel. Sustainable tourism aims to strike a balance between the environmental, economic and social effects of tourism. The aim of this article is to find the optimal itinerary for an individual traveller to a congress hotel in Valencia. The main research question is as follows: Which itinerary has the best overall score in terms of CO 2 per passenger kilometre, travel time and direct cost? Three scenarios were compared: Airplane plus, train plus and car only. The choice of these three suits the travel purpose and length. Literature was used to find the necessary trip and vehicle data. This was fed into a microsimulation model. The main outcome of the simulation experiment is that the environment would benefit if the traveller would favour the train plus scenario. This, however, has a time penalty compared to the airplane plus scenario. A trip by car is the least preferable, because of CO 2 emissions, travel safety and time. Direct costs of all three scenarios are comparable. Rail has the lowest emissions per passenger in the scenarios, hence it is important that network improvement programs continue and ticket prices stay in line with the price of travelling by car or airplane. An individual traveller was chosen for different reasons. One reason is that after understanding individual touristic travel decisions and their impact, it is a small step to estimate what is feasible if many more individuals would become ecofriendly touristic travellers. A second reason is that it allows an advice for governments and businesses to target individual tourists. Finally, there is the communicative impact of simplification on individual tourists. Transport and Plannin
Hoe SMART willen we rijden; De autonome auto als stedelijke vervoersoplossing of -probleem?
No full textEen autonome auto bestond al in een droombeeld van GM in de VS rond 1940. Zo’n 40 jaar verder, in 1977, reed de eerste autonome auto uit een Japans lab. Sinds decennia wordt door ingenieurs gewerkt aan systemen die de autobestuurder overbodig kunnen maken. De stap van zelf rijden naar vanzelf rijden wordt door autofabrikanten ingeleid door in bestaande auto’s extra functies in te bouwen. Het gaat daarbij om bijvoorbeeld parkeerhulp, adaptieve cruise control en uitwisseling van informatie tussen voertuigen, die bestuurders (lastige) lastige taken uit handen nemen. Autonoom rijden vereist in de basis dat een scala van systemen in de auto betrouwbaar samenwerken. Handsfree rijden is technisch mogelijk op speciale wegen, binnen (aparte) rijstroken en onder de juiste weers- en verkeerscondities. Het samen rijden met conventioneel bestuurde auto’s onder variërende weg- en omgevingscondities levert echter enorme uitdagingen op. De interactie met andere auto’s (met en zonder deze systemen) en vooral het veilig kunnen anticiperen op onverwachte situaties vergt een beoordelingsvermogen dat voorlopig alleen aan mensen lijkt voorbehouden. De lopende praktijkproeven, we zijn opnieuw 40 jaar verder, zijn bedoeld om ook dan veilig te kunnen rijden.Zijn auto(snel)wegen al een complexe omgeving, dit geldt nog meer voor steden. Wij poneren echter de stelling dat techniek bij de toelating van autonome auto’s in stedelijke gebieden geen doorslaggevende rol zal spelen. Daar is het van doorslaggevend belang of autonome auto’s onderdeel zouden kunnen zijn van een oplossing voor de vele problemen en uitdagingen die onze steden kennen, zoals groeiend ruimtegebrek, afnemende leefbaarheid en milieukwaliteit, en bereikbaarheid en betaalbaarheid van vervoerssystemen; de stedelijke “systeemwensen/eisen“. De auto krijgt in steden al lang geen vrij baan meer. Na jaren van beleidsmatige twijfel lijkt nu de tijd rijp om een forse stap verder te gaan om de leefbaarheid in steden structureel te verbeteren. Het gebruik van auto’s in steden staat nu ter discussie. De autoindustrie neemt deze “bedreiging” serieus en schuift de autonome auto als reddingsboei naar voren. Dit brengt ons bij de hoofdvragen van dit conceptuele paper: 1) Wat zijn de belangrijkste uitdagingen in onze steden en welke rol speelt verkeer en vervoer daarin?2) Welke systeemeisen/wensen kunnen hieruit afgeleid worden?3) Is het wel zo smart om privéauto’s in steden nog zoveel ruimte te geven?4) Welke rol zouden autonome auto’s kunnen spelen in steden?Het paper eindigt met conclusies en overwegingen voor diverse belanghebbenden.<br/
More space and improved living conditions in cities with autonomous vehicles
No full textMany people live in cities today. Many more will do so in future. This increases the demand for space and (space for) transport. Space to expand roads is usually scarce. Building tunnels or elevated bridges is very expensive. Solving one bottleneck creates a next bottleneck downstream. More road infrastructure leads to more cars and more cars to more congestion and externalities. Megacitiesinvest in large-scale (preferably underground) public transport. Smaller cities lack the required number of travellers and the money to warrant the high investment costs. In a sustainable city the supply of goods, services, water, energy and transportation should differ from the current practice.New car technologies are interesting, in particular the nearly roadworthy self-driving (autonomous) cars. It is still very demanding to let these share roads with conventional cars, cyclists and pedestrians. Cities lack the space for a separate network for these cars, yet. A socially challenging alternative would be to replace all private cars by shared electric self-driving cars and small shuttlebuses and integrate these with mass transport, cycling and walking. Passenger transport would need much less space for driving and parking. Congestion will vanish. Local air pollution, noise and use of resources to produce cars and road materials are reduced. Reclaimed space can be used to create a more sustainable and social environment and to optimize city logistics. The building blocks of such a (public-private) system exist already or will become available in the future
Towards zero CO2-, NOX- and PM10-emissions by passenger cars: Technology & Behaviour
No full textModern societies rely on mass mobility, in particular by private car. Car numbers are growing worldwide due to economic and other factors. Nearly, all have engines that run on fossil fuels. Use of fossil fuels contributes to climate change (via CO 2-emissions) and local air pollution (primary NO x- and PM 10-emissions). Both have profound environmental and health implications. The paper explores the technical and behavioural feasibility of zero-emission private car use in The Netherlands in 2030. Base year is 2010. The following research questions are addressed: 1. How much CO 2, NO x and PM 10 did passenger cars emit in 2010? 2. How much will this be in 2030? 3. What would these figures be if electric cars become mainstream in 2030? 4. What would the impact be of sustained urbanization on these emissions? 5. How would a greener power mix in electric power plants affect the emissions of CO 2, NO x and PM 10 by electric cars? A simulation model was used to quantify a rich set of scenarios. Many car manufacturers aim to produce more (fully) electric vehicles (FEVs) in the coming years. More FEV translates into less (growth in) consumption of fossil fuels and emissions. The remaining emissions are still on the high side. Urbanization may support a further reduction. It reduces car ownership and use and thereby the growth in car kilometres, fossil fuel consumption and emissions. Growing production of renewable energy gradually makes the power mix greener. The most extreme combination of scenarios enables society to reduce CO 2-emissions far beyond the −50% target in 2030 for the assumed car mobility scenario. The feasibility of this outcome is rather uncertain. An extension of decades of neoliberal, market-first transport policy would very likely slow down the pace of the transition. </p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
