1,721,209 research outputs found
Automated fabrication of shape models of free-form objects with a sculpturing robot.
No full textIndustrial Design Engineerin
Microscopic interaction behavior between individual pedestrians
No full textDue to growing mobility in densely populated urban areas, public pedestrian walkways are becoming more and more crowded. Since space in these densely occupied areas is highly valued, the use of every square meter must be evaluated carefully. Microscopic pedestrian simulation models can provide such evaluation. However, fundamental knowledge on individual pedestrian behavior underpinning these models is hardly available. This study focuses on the so-called interaction behavior between individual pedestrians. It comprises the identification of aspects that influence individual interaction behavior, their effects on pedestrian movement and how these effects can be described and predicted. Assessment criteria and pedestrian experiments In unhindered walking, personal walking capabilities determine the intended path in lateral and in longitudinal direction. Walking outside of this intended path in unhindered walking is defined as interaction movement. Also, the passing side and the extent of evasion from the mean intended path are investigated. The effects of the direction of approach (i.e. bidirectional, crossing and overtaking situations), individual gender and motion pace and small groups on these three assessment criteria are examined. Laboratory experiments have been performed to obtain data on individual pedestrian interaction behavior. In these experiments twelve participants are initially asked to walk a length of 20 meters unhindered by other pedestrians. Thereafter, two or three participants are asked to walk simultaneously, in such a way that interaction between them is provoked. This has resulted in 1586 trajectories of individual pedestrians. Analyses on unhindered walking and interaction movements The unhindered trajectories are used to derive boundaries for the intended path in unhindered walking, mean walking paths and mean walking speeds. In addition, a method is presented to analyze the swaying effect in unhindered walking. It has been shown in this study that the observed step lengths and step frequencies are inversely proportional to each other. It is found that individual pedestrians perform interaction movement in 88% of the interaction situations observed in this study. These movements can be interpreted as some gallantry towards other pedestrians. This finding justifies the detailed modeling of pedestrian interaction movements in microscopic simulation models. In the bidirectional situation pedestrians strongly prefer passing each other on the right hand side. In crossing situations, walking in a hurry increases the probability of passing in front of other pedestrians and meeting a small group of two pedestrians increases the probability of passing at the back of this group. The passing side and the direction of approach mainly determine the direction and the extent of evasion from the individual mean walking path and from the individual mean walking speed during interaction. Pedestrians seem to prefer larger lateral evasion in bidirectional situations and larger longitudinal evasion in crossing situations. Men laterally evade more than women and hurried pedestrians laterally evade more than normally walking pedestrians. It seems that hurried pedestrian are either granted ‘right of way’ or that they take the initiative themselves in an early stage of the interaction process. The extent of evasion is larger when small groups are encountered. Implications for pedestrian modeling and recommendations for further research The observations on pedestrians in individual interaction situations differ in a number of issues from observations on individual pedestrians in flows. This indicates that behavioral reactions of individual pedestrians to other individual pedestrians differ from behavioral reactions of individual pedestrians to pedestrian flows. Moreover, it follows from this study that the passing side determines the ensuing lateral and longitudinal evasion. A conceptual model for implementing this into pedestrian models is given in the attached figure. This model differs from other models since interaction movements are determined based on a decision on the passing side instead of the other way around. Furthermore, hurried pedestrians behave significantly different than normally walking pedestrians and this aspect should thus be modeled. Several aspects regarding individual pedestrian interaction need further research. Among these are the initiation moment of interaction movements and the effects of gender, body size and age on pedestrian interaction. These aspects can be investigated with the observations obtained in this study. The effects of multiple individual pedestrians on the individual interaction behavior (i.e. individual behavior within pedestrian flows) were not investigated in this study. To gain knowledge on these effects it is of interest to analyze whether behavioral reactions of individual pedestrians to other individual pedestrians significantly differ from behavioral reactions of individual pedestrians to pedestrian flows.Transport & PlanningCivil Engineering and Geoscience
Camera Planning in Virtual Environments using the Corridor Map Method
No full textPlanning high-quality camera motions is a challenging problem for applications dealing with interactive virtual environments. This challenge is caused by conflicting requirements. On the one hand we need good motions, formed by trajectories that are collision-free and keep the character that is being followed in clear view. On the other hand, we need frame coherence, i.e. the view must change smoothly such that the viewer does not get disoriented. Since camera motions dynamically evolve, good motions may require the camera to jump, leading to a broken frame coherence. Hence, a careful trade-off must be made. In addition to this challenge, interactive applications require real-time computations, preventing an exhaustive search for `the best' solution. We propose a new method for planning camera motions which tackles this trade-off in real-time. The method can be used for planning camera motions of NPC's and first-person characters. Experiments show that high-quality camera motions are obtained for both scenarios in real-time
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
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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