1,720,959 research outputs found
Petri nets and dynamic causality for service-oriented computations
No full textWhen dealing with service oriented computations the dependencies among the various distributed activities may be complex and difficult to represent statically. Recently Event Structures where the causality may change dynamically have been introduced and have been related with many other kind of Event Structures (with a particular focus on expressivity). In this paper we relate them to a kind of (labeled) Petri net which turns out to cover these new Event Structures. This relationship empowers the usage of all the available verification tools based on Petri nets, giving practical and usable means for the verification of the complex and distributed system whose behavior is modeled by this kind of event structures
Investigations on Fragments of First Order Branching Temporal Logic
No full textWe investigate axiomatizability of various fragments of first order computational tree logic (FOCTL) showing that the fragments with the modal operator F (H, respectively) are non axiomatizable. These results shows that the only axiomatizable fragment is the one with the modal operator next (X) only
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
Model Checking Reversible Systems: Forwardly
No full textReversibility is nowadays playing a major role when dealing with systems, allowing to revert to
safe states of systems evolutions. For instance reversibility can be applied to causal-consistent debugging.
On the other hand, Linear Temporal Logic (LTL) has been used to formalize properties that a system
may fulfil, and it may be equipped with past operators. This makes this logic appealing to express
and prove properties of a reversible system. In this paper we investigate this feature, and we use the
classical approaches to model check LTL formulas on unfoldings, in order to deal with reversible systems
Relating Reversible Petri Nets and Reversible Event Structures, Categorically
No full textCausal nets (CNs) are Petri nets where causal dependencies are modelled via inhibitor arcs. They play the role of occurrence nets when representing the behaviour of a concurrent and distributed system, even when reversibility is considered. In this paper we extend CNs to account also for asymmetric conflicts and study (i) how this kind of nets, and their reversible versions, can be turned into a category; and (ii) their relation with the categories of reversible asymmetric event structures
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
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