1,721,000 research outputs found
Communication and Mobility Control in Boxed Ambients
Full text linkBoxed Ambients (BA) replace Mobile Ambients' open capability with communication primitives acting across ambient boundaries. The expressiveness of the new communication model is achieved at the price of communication interferences whose resolution requires synchronisation of activities at multiple, distributed locations. We study a variant of BA aimed at controlling communication as well as mobility interferences. Our calculus modifies the communication mechanism of BA, and introduces a new form of co-capability, inspired from Safe Ambients (SA) (with passwords), that registers incoming agents with the receiver ambient while at the same time performing access control. We prove that the new calculus has a rich semantics theory, including a sound and complete coinductive characterisation, and an expressive, yet simple type system. Through a set of examples, and an encoding, we characterise its expressiveness with respect to both BA and SA
Communication Interference in Mobile Boxed Ambients
Full text linkBoxed Ambients (BA) replace Mobile Ambients’open capability with communication primitives acting across ambient boundaries. Expressiveness is achieved at the price of communication interferences on message reception whose resolution requires synchronisation of activities at multiple, distributed locations. We study a variant of BA aimed at controlling communication interferences as well as mobility ones. Our calculus draws inspiration from Safe Ambients (SA) (with passwords) and modifies the communication mechanism of BA. Expressiveness is maintained through a new form of co-capability that at the same time registers incoming agents with the receiver ambient and performs access control
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
Access Control for Mobile Agents: the Calculus of Boxed Ambients
Full text linkBoxed Ambients are a variant of Mobile Ambients that result from dropping the `open' capability, and introducing new primitives for ambient communication. The new model of communication is faithful to the principles of distribution and location-awareness of Mobile Ambients, and complements the constructs `in' and `out' mobility with finer-grained mechanisms for ambient interaction.
We introduce the new calculus, study the impact of the new mechanisms for communication o typing and mobility, and show that they yield an effective framework for resource protection and access control in distributed syste
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
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