1,721,104 research outputs found
First-Order Strong Progression for Local-Effect Basic Action Theories
No full textIn a seminal paper Lin and Reiter introduced the notion of progression for basic action theories in the situation calculus. The idea is to replace an initial database by a new set of sentences which reflect the changes due to an action. Unfortunately, progression requires secondorder logic in general. In this paper, we introduce the notion of strong progression, a slight variant of Lin and Reiter that has the intended properties, and we show that in case actions have only local effects, progression is always first-order representable. Moreover, for a restricted class of local-effect axioms we show how to construct a new database that is finite
On First-Order Definability and Computability of Progression for Local-Effect Actions and Beyond
Get PDFIn a seminal paper, Lin and Reiter introduced the
notion of progression for basic action theories in
the situation calculus. Unfortunately, progression is
not first-order definable in general. Recently, Vassos,
Lakemeyer, and Levesque showed that in case
actions have only local effects, progression is firstorder
representable. However, they could show
computability of the first-order representation only
for a restricted class. Also, their proofs were quite
involved. In this paper, we present a result stronger
than theirs that for local-effect actions, progression
is always first-order definable and computable. We
give a very simple proof for this via the concept
of forgetting. We also show first-order definability
and computability results for a class of knowledge
bases and actions with non-local effects. Moreover,
for a certain class of local-effect actions and
knowledge bases for representing disjunctive information,
we show that progression is not only firstorder
definable but also efficiently computable
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
aus Berlin
No full textDiese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar. To my parents Acknowledgements First and foremost, I would like to thank my advisor Gerhard Lakemeyer. I particularly enjoyed our discussions, from which I took great benefit. He taught me to scrutinize preliminary conceptualizations in order to clarify and structure my ideas, and had a profound impact on my scientific education. I am also indebted to him for reading and commenting on earlier versions of this thesis. This work wouldn’t have been possible without his help and advice. I would also like to thank Michael Beetz who had a strong influence on my view of high-level robot control. Thanks also to Gero Iwan, who was always interested in the problems I struggled with and who gave me useful suggestions, Frank Dylla, Günter Gans and Alexander Ferrein. I am also grateful to Michael Thielscher who kindly took on the task of second reviewer for this thesis. Finally, I would like to thank Simone for bravely listening to my complaints during the tough times an
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
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