1,720,974 research outputs found
Applying Mobility Pricing Instruments to Optimize Traffic and Transport
No full textAmong numerous, established instruments of Mobility Pricing, e.g. public transport or parking fees, new approaches for pricing the mobility can be found more and more. City toll systems, like the introduced ones in London and Stockholm, gain a lot of attention, also internationally. As a consequence, in many countries, the opportunities and risks of new instruments are going to be debated intensivly. In order to support the upcoming discussions, this article looks into the requirements and the effects of the different mobility pricing instruments. The potential goals of mobility pricing are presented, and an overview of the achieve political and planning goals and to optimize traffic and transport systems. An objective and substantiated discussion of new instruments appears to be not only desirable but absolute necessary, in terms of a sustainable design of our traffic and transport systems
Travel demand management and road user pricing : success, failure and feasibility
No full textThroughout the world, traffic levels are increasing and, in urban areas, these increasing levels have led to pressures on the road networks which are causing serious economic, environmental and social problems. This book examines the full range of 'push and pull' Travel Demand Management measures. This covers areas of regulatory, pricing, planning and persuasive policies to encourage individuals to make their trips in off-peak periods, by a different mode or to find another way of carrying out the trip purpose. Applying such measures can result in a more efficient transport system, improved environmental conditions and improvements in safety as well as revenue generation for use on alternative transport systems. The editors conclude with a summary of findings within the book and suggestions for best future practice
Development of a questioning to estimate the market potential of electric vehicles
Full text linkFür die Entwicklung eines Befragungsdesigns ist eine Vielzahl von Aspekten zu beachten. Im vorliegenden Fall handelt es sich um die Konzeption einer Mobilitätsbefragung zur Ermittlung des Potenzials von Elektromobilität. Es sollte ermittelt werden, wie viele Pkw-Nutzer unter bestimmten Bedingungen bereit sind, ein Elektroauto zu kaufen. Als Befragungstechnik wurde "stated-preference" - ein hypothetischer Ansatz - ausgewählt. Um die Qualität der entwickelten Befragungsunterlagen zu überprüfen, wurden 20 Pilottests vor Beginn der eigentlichen Erhebung durchgeführt. Diese als Pre-Tests zu bezeichnenden Untersuchungen brachten wichtige Erkenntnisse, welche bei der Entwicklung des finalen Befragungsdesigns berücksichtigt wurden. Die vor allem qualitative Interpretation führte zu wesentlichen Ergebnissen hinsichtlich Aspekte des Designs der Befragungsunterlagen, organisatorische Aspekte des Befragungsablaufs, inhaltliche sowie sonstige Aspekte der Befragung.In order to develop a questioning, a lot of aspects have to be considered. The main focus of this diploma thesis was to design a questioning to calculate the potential of electric vehicles as a new form of mobility. The selected questioning technique is stated-preference, a member of the hypothetical stated-response-family.As a difference to revealed preferences, it is possible to find out about possible effects of alternatives that do not exist yet. Before launching the actual questioning, the intent was to prove and secure the quality of the questionnaire. For this reason, 20 pre-tests were made.These pre-tests brought important insights that were used to construct the final questioning. Due to a mainly qualitative analysis, essential results regarding different aspects of a questioning could be achieved
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
Impact of the modal split on the density of population and on the economies of agglomeration in metropolitan areas
Full text linkPositive Agglomerationseffekte ("economies of agglomeration") sind Triebkraft für die Bildung von Agglomerationen. Eine Optimierung der Bevölkerungsdichte durch den Markt ist nach dem derzeitigen Stand der Forschung nicht gegeben, denn externe Kosten des Verkehrs bewirken ein Marktversagen. Externe Kosten des Verkehrs mindern durch ihren Einfluss auf die Bevölkerungsdichte die Größe der positiven Agglomerationseffekte. In dieser Arbeit wird eine Hypothese darüber aufgestellt, wie stark sich eine Änderung des Modal-Split (und damit eine Änderung der Höhe externer Verkehrskosten) auf die Bevölkerungsdichte von Großstädten und in weiterer Folge auf die Größe der positiven Agglomerationseffekte auswirkt. Diese Wirkung externer Verkehrskosten (insbesondere Staukosten) auf die Größe von Agglomerationseffekten stellt einen zusätzlichen externen Effekt des Verkehrs dar, dessen Größe abgeschätzt wird. Je höher die Bevölkerungsdichte ist, desto höher ist einerseits die Erreichbarkeit; desto höher sind aber andererseits Staukosten, welche die Erreichbarkeit vermindern. Das Maximum der Erreichbarkeit ist gegeben, wenn der Grenzzuwachs an Erreichbarkeit durch weitere Verdichtung gleich dem Grenzverlust an Erreichbarkeit ist. Aus der Annahme, dass rational handelnde Akteure unter den gegebenen Bedingungen versuchen werden, die Erreichbarkeit zu maximieren, wird die folgende Hypothese abgeleitet: Die Bevölkerungsdichte von Städten strebt jenem Wert zu, der beim jeweils gegebenen Modal Split ein Maximum der Erreichbarkeit ermöglicht. Die Hypothese wird anhand eines Modells überprüft. Das Modell liefert für jeden Modal Split jene Bevölkerungsdichte, die laut Hypothese zu erwarten ist. Empirische Daten zu Modal-Split und Bevölkerungsdichte von 46 internationalen Beispielstädten zeigen beim Vergleich von Ist-Wert und dem gemäß Modell erwarteten Wert ein Bestimmtheitsmaß von R2 =0,833. Eine zweite Hypothese betrifft die Auswirkungen der Verkehrsmittelwahl im Personenverkehr auf die Größe externer Agglomerationseffekte:In Städten besteht der größte externe Effekt des Verkehrs in dem Einfluss, den die die Verkehrsmittelwahl im Personenverkehr auf die Produktivität der in der Stadt angesiedelten Betriebe ausübt. Um Hypothese II zu prüfen, wird das Erreichbarkeitsmodell um die Änderung der Wertschöpfung erweitert, die laut vorliegenden Forschungsergebnissen mit Änderungen der Erreichbarkeit verbunden sind. Bei Minimal-Annahmen ergibt sich für Wien für die Spitzenstunden des Tages ein negativer externer Grenz-Agglomerationseffekt pro Pkw-Fahrt in der Größenordnung der externen Grenz-Staukosten.Economies of agglomeration are the moving force behind the formation of agglomerations. Economies of agglomeration depend on accessibility. According to previous research a private land market will not lead to the optimal level of urban density which would provide the highest accessibility. The reason for this market failure is the mainly seen in the external cost of congestion. The topic of this dissertation is to provide better understanding of the relations between urban density, accessibility and modal split. Increasing urban density will on one hand increase accessibility because the distance to potential destinations gets shorter. On the other hand with increasing density accessibility will be reduced by the increase of congestion which lowers the speed of travel. This means that there is an optimum of urban density which will provide the highest accessibility possible. But there is another factor which has to be taken into account. Different modes of transport do not require the same road capacity. At a certain transport performance the intensity of congestion depends on the modal split between public and private transport. This means that the optimum density of a metropolitan area depends on the modal split. Because participants in the land market are supposed to look for good accessibility of production sites and dwellings this leads to a simple thesis: If a certain modal split is given the urban density of metropolitan areas will adjust to a level at which the maximum of accessibility is reached at this given modal split. To check this hypothesis a model is designed which describes accessibility as a function of modal split and density. This model yields the density at which the maximum of accessibility is reached as a function of modal split. A comparison between the actual densities of 46 metropolitan areas in North America, Europe, Asia and Australia and the density predicted by the thesis shows a coefficient of determination of 0.83. In itself congestion caused to other road users by each additional vehicle is a major external effect. By its double impact on travel speed and urban density congestion reduces positive economies of agglomeration which constitutes an additional external effect of transport. Above a certain density of population this additional external effect can be shown to be at least the same size as the external cost of congestion.<br /
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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