1,720,972 research outputs found
Identification of the Hierarchy in Public Transport Networks based on Passenger Flow Patterns
No full textIn this study, a data-driven, generic and transfer-based methodology for separation and ranking the PTNs has been put forward. With the hierarchy of a network, this is beneficiary for the management and operation of operators for focusing on the higher level network layer and in turn provide better service for passengers. The study introduces three steps to rank the hierarchy of a PTN: (1) using the passenger journey and ride data to derive transfer flow matrix; (2) applying C-space network representation with community detection method to separate and visualize the PTN layer; (3) performing ranking method, regarding inner- and intra- transfer flow. To this end, the hierarchy of a PTN could be presented with temporal attributes. Different day of week and various time period of a day could potentially yield different hierarchy. The proposed unsupervised learning algorithm is based on passenger transfer flow data, independent from geographic location and the mode of transportation. The study shows that the level is changing based on the selected time slot and can be a mixture of different modes, which is dissimilar from the hierarchy purely based on qualitative method
Riverine flood risk screening with a simple network-based approach: A proof of concept in the Ganghes-Brahmaputra basin
No full textFloods cause major problems around the world. Over 35 million people were affected by floods in 2018. They have a growing worldwide impact on life and property. Changes in climate conditions lead to unanticipated variations in glacial runoffs, snowmelt and precipitation, which all significantly changing river flows. An imbalance in river network equilibrium leads to flooding and often ends up causing tremendous damage to society and the environment. Regions that are perceived to be downstream from the source of flooding may end up taking the brunt of the river force due to flood cascades. Floods account for about a third of all natural catastrophes worldwide, they cause more than half of all fatalities and are responsible for a third of the overall economic loss.Modelling approaches are often used to determine flood consequences. Two types of flood models are commonly used: statistical models and flow simulation models. Statistical methods are easy to use but provide limited insight into flood problems. Flow simulation models’ results can be very accurate, especially for hydraulic simulation models. However, these models are expensive to use and develop, and they require a lot of data. These requirements make them unsuitable for application in developing countries and analysing large watersheds. Flood risk screening models try to solve these problems. They are suitable for use in data-sparse regions and are efficient in terms of omputational costs. However, there is a lack of knowledge between river structure and cascading flood effects, and there is a lack of models that are efficient, easy to understand, use topological data and have the purpose of risk screening. In this research, we show a flood model based on complex network theory to efficiently study the cascading effects of floods in riverine systems. Cascading effects are defined as floods that occur as a result of water waves through the system that originate from upstream sources. The developed model uses the hydrological Muskingum routing method. We found that it was possible, notwithstanding many assumptions and a lack of data, to reproduce system behaviour during an extreme flood event in the Ganges-Brahmaputra Basin. Satellite elevation data were used to construct the river network, and satellite precipitation data was used to feed the model. The model can indicate high risk reaches based on the simulated overflow, the flow exceeding a predefined capacity. No existing models are known that can do this, on a laptop, within seven min- utes per simulated day, with limited data for a watershed that exceeds the size of one million square kilometres. The network structure of the model makes it possible to achieve a better understanding between river typology and cascading flood effects. The model is not without its limitations. It cannot pinpoint when and where floods will occur, because it only calculates overflow. Moreover, flood failure mechanisms are not yet included in this model. Failure mechanisms will change model behaviour: when a flood occurs water temporarily leaves the system, which reduces downstream risk. Overflow cascades, therefore, would be shorter in reality than in this model. The model is a proof of concept that shows the potential of a network theory-based risk screening method in flood simulation context. Its properties make it suitable for analysing the effects of changing precipitation patterns, which, for example, could originate from climate change studies. Another use case is real-time forecasting of discharge levels if the mode is combined with real-time discharge levels and precipitations forecasts. The model can be used as an early warning system: alerting when and where high discharge levels are expected. We anticipate our model to be a starting point for policy screening and scenario analysis. Sugges- tions are made to include policy options within the model. Policy analysts can then use the model to compare different policy interventions for all kinds of (future) scenarios. The model should not be seen as a replacement of the advanced hydraulic simulation models, but as a complementary tool useful at an earlier moment in a design process with the purpose of screening options. Ultimately it can become a framework with the aim to support informed decision-making.https://github.com/bcvanmeurs/rnaEngineering and Policy Analysi
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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