1,720,977 research outputs found
Assessing Benefits in Vehicle Speed and Lateral Position when Chevrons with Full Retroreflective Sign Posts are Implemented on Rural Horizontal Curves
Get PDFDriving a horizontal roadway curve requires a change in vehicle alignment and a
potential reduction in speed. Curves may present a challenging situation during adverse
conditions or to inattentive drivers. Chevron signs provide advanced warning and
positive guidance throughout the curve. Some agencies place supplemental
retroreflective material on sign posts to enhance the signs? conspicuity and visibility.
The objective of this study was to determine any incremental benefits in vehicle speed
and lateral lane position when retroreflective material was applied to Chevron sign posts
(ChevFull). This study analyzed three separate evaluation scenarios in a before, after,
and after-after experimental design. There was an existing Baseline evaluation with no
vertical delineation, a standard Chevron evaluation, and an experimental ChevFull
treatment evaluation. Data collection measured vehicle speed and lateral position data at
the point of curvature and mid-point on two separate curves. Findings showed that both
Chevrons and the ChevFull treatment moved vehicles away from oncoming traffic by
about 15 inches. Overall, there was little difference between the lateral position findings
of the two Chevron treatment scenarios. Chevrons achieved a 1.28 MPH reduction in
mean vehicle speed from the Baseline evaluation and the ChevFull treatment obtained a
2.20 MPH reduction. The findings determined that the benefits of the ChevFull
treatment were not substantial. The author recommends that the MUTCD should
continue to present the ChevFull treatment as an optional delineation tool. Based on this
research, the author does not recommend any changes to the MUTCD
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
Field location & marking of no-passing zones due to vertical alignments using the global positioning system
Get PDFPassing on two-lane roadways is one of the most difficult movements a driver may
perform and guidance on where passing maneuvers are prohibited is given by the
location of no-passing zones. Currently the processes for identifying no-passing zone
locations can be daunting and many practices require work crews to operate in the
roadway creating potentially hazardous situations. Due to these challenges new
alternatives need to be developed for the safe, accurate, and efficient location of nopassing
zones on two-lane roadways.
This thesis addresses the use of Global Positioning System (GPS) coordinates to
evaluate sight distance along the vertical profile of roadways to provide an alternative
for an automated no-passing zone location system. A system was developed that
processes GPS coordinates and converts them into easting and northing values, smoothes
inaccurate vertical elevation data, and evaluates roadway profiles for possible sight
restrictions which indicate where no-passing zones should be located. The developed automated no-passing zone program shows potential in that it identifies
the general location of no-passing zones as compared to existing roadway markings.;
however, as concluded by the researcher, further evaluation and refinement is needed
before the program can be used effectively in the field for the safe, accurate, and
efficient location of no-passing zones
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
Residential accessibility's relationships with crash rates per capita
Get PDFThis paper examines the relationship between residential accessibility, i.e., accessibility from a person's home address, and their likelihood of being in a crash over a three-year period. We explore two potential relationships with accessibility. The first is that persons who live in areas with high destination accessibility may drive less and therefore are less likely to be in vehicular crashes. The second is that persons who live in high vehicle miles traveled (VMT) accessibility areas may be exposed to higher levels of traffic in their regular activity space and therefore may be more likely to be in crashes of all modal types. Examining traffic analysis zones in Knoxville, Tennessee, this research finds some evidence for each of these hypothesized effects. These oppositely directed effects have dominant influence within different travel-time thresholds. The first relationship between destination accessibility and fewer crashes is found to be strongest for 10-minute auto accessibility, whereas the second relationship between VMT accessibility and more crashes is found to occur at 10-minute, 20-minute, and 30-minute thresholds.Merlin, Louis A.; Cherry, Chris R.; Mohamadi-Hezaveh, Amin; Dumbaugh, Eric. (2020). Residential accessibility's relationships with crash rates per capita. Retrieved from the University Digital Conservancy, 10.5198/jtlu.2020.1626
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