1,720,983 research outputs found
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
River transport by Barges : Resistance and Directional Stability Problems
No full textRiver transport of bulk goods and liquids is mostly carried out by barges, especially on long distances, and it can be pushed or towed. The transport by pushed barges is safer and generates less resistance, but in some cases the transport with towed barges is required. In the latter case it must be ensured a good route-keeping to the barges, in order to be easily controlled and sure from getting out of the planned route and to be stranded on a shore. In general the route keeping is guaranteed by couples of stern skegs, which must be designed according to the barge typology. In a river navigation also the effects due to shallow water and the river currents must be taken into account. In this paper the mentioned problems will be explained in detail and some results obtained with experiments with model barges in an experimental tank will be presented
Concept Design of a Clinic Ship for the Health Care System in Peruvian Amazon Basin
No full textIn the Peruvian Amazon basin rivers are the only link among the small communities, scattered on a wide territory. With that in mind and according to the needs of local communities, a health care network system based on mobile clinic units onboard small crafts has been conceived, within a cooperation programme between the Universidad Católica Santo Toribio de Mogrovejo (Perú) and the University of Trieste (Italy). This way, patients along the inland waterways can be reached. Ships to be operated in this service, must be especially designed to sail in different environmental conditions: in shallow water during dry season, against high currents during wet season and eventually in rivers showing both phenomena. Moreover, manoeuvrability and landing are subjects of major interest in ships designed for these regions. Within this frame, a study has been carried out to define main characteristics for a small clinic ship. General arrangement plans including medical equipment and clinic lay-out have been drawn. Then, according to clinic platform needs, the major engineering aspects of the ship have been studied to a concept design level: main dimensions have been defined and hull geometry has been optimized for waterway navigation; scantling of all the ship’s structures has been completed, based on the most recent rules issued by classification societies and according to EC guidelines for inland navigation; propellers and propulsion plant have been studied on the whole, considering shallow water effects on resistance; intact and damaged stability and buoyancy criteria have been met according to IMO regulations
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
The Evolution of the Regulatory Stability Regime for Fishing Vessels
No full textThe intact stability standards for fishing vessels are considered in their historical development, all fairly recent. Regional differences, that result in the average size of vessels, are considerable together with an extremely poor harmonization of the different regimes of safety. A decisive effort for improvements in the safety levels and in general in the living conditions in the fisheries sector has been undertaken in the frame of the close cooperation established between the IMO, ILO and FAO. In this context, are at an advanced stage of development regulations, mostly of voluntary application, which greatly extend the lower extreme of the interval of ship lengths previously considered by the Torremolinos Convention. With regard to the latter, a major effort is underway to get to the ratification and entry into force internationally as an IMO instrument of the revised Torremolinos Protocol as it results after the Diplomatic Conference held in Capetown in 2012. In this review paper, present situation is critically analyzed also in the light of the contributions given by the research group operating at University of Trieste
A nonlinear dynamics perspective on some aspects of towing operations relevant to safety and energy efficiency
No full textScheduled and emergency towing operations are carried out daily, both at sea and in restricted waters, as a means of transporting goods, aiding ships during berthing and casting-off or rescuing units in distress. Even in mild weather conditions, such activities can pose serious threats to the safety of the personnel and units involved and to the environment. This study investigates the dynamics of a tug-tow system, where towing is carried out by means of a single elastic towing line. A simplified model is used, in which the tug is modelled as a point-particle with a prescribed motion, while the dynamics of the towed object is modelled as a 3-DOF (surge/sway/yaw) nonlinear dynamical system. Equilibria of the system are analysed through a bifurcation analysis technique, supplemented by time-domain simulations, if/when necessary. An example application is reported for the case of towing of a barge-like hull, showing the effects of several parameters: ship speed, towline length, water depth and wind. The performed calculations confirm that, depending on the configuration parameters, multiple stable/unstable steady-state towing positions may exist. It is also clarified in this study that, in the absence of stable equilibria, the potentially dangerous oscillating phenomenon called “fishtailing” takes place
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