1,721,011 research outputs found
Programming with Actors - State-of-the-Art and Research Perspectives
No full textAfter more than 40 years by their invention, actors are nowadays in the mainstream, as a reference model for designing and developing concurrent and distributed systems.
The actor model was introduced by Carl Hewitt and colleagues in 1973 [7], as a mathematical model of concurrent computation in which actors play the role of universal primitives of concurrent computation. In response to a message that it receives, an actor can: make local decisions, create more actors, send more messages, and determine how to respond to the next message received. Actors may modify their own private state, but can only affect each other through messages (avoiding the need for any locks). Since its conception, the model served both as a framework for a theoretical understanding of computation and as the theoretical basis for several practical implementations of concurrent systems [6].
In 80ies and 90ies the model has been a main reference to understand and define the extension of Object-Oriented Programming towards concurrency, e.g. Concurrent OOP [1, 2, 11, 4].
On the mainstream side, the panorama has been dominated by sequential programming until middle of 2000ies, when the “concurrency revolution” started to raise [9,5]. Since then, concurrent, asynchronous, distributed programming have gradually become part of everyday design and programming.
If 80ies and 90ies were dominated by a vision in which mainstream pro- gramming and programming paradigms could abstract from concurrency and distribution, in recent years there has been an increasing awareness that this is not feasible (e.g., if you want to build reactive applications1), and – moreover – first-class concurrent abstractions, such actors and message passing, provide an effective modeling and designing power to deal with the complexity of modern applications and application domains [10, 3].
AGERE! workshop started in SPLASH in 2011 to investigate the definition of suitable levels of abstraction, programming languages, and platforms to support and promote a decentralized mindset in solving problems, designing systems, programming applications, including the teaching of computer programming [8]. That is, the question is how to think about problems and programs taking de- centralization of control and interaction as the most essential features. To this end, actors and agents were taken as key main references, recognised as two main broad families of concepts, abstractions and programming tools described in literature that explicitly promote such a decentralized thinking.
The set of papers collected in this volume originated from the AGERE! work- shop series – last edition was in 2017 – and concern the application of actor-based approaches to mainstream application domains and the discussion of related issues
Message from the Chairs - AGERE 2015 - Proceedings of the 5th International Workshop on Programming Based on Actors, Agents, and Decentralized Control
No full textThe proceedings contain 6 papers. The topics discussed include: deny capabilities for safe, fast actors; objects as session-typed processes; exploring AOP from an OOP perspective; Jacco: more efficient model checking toolset for Java actor programs; manyfold actors: extending the C++ actor framework to heterogeneous many-core machines using openCL; and Akka.js: towards a portable actor runtime environment
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
Programming Actor-Based Collective Adaptive Systems
No full textIn recent years, we are witnessing a growing interest in large-scale situated systems, such as those falling under the umbrella of pervasive computing, Cyber-Physical Systems, and the Internet of Things. The actor model is a natural choice for designing and implementing such systems, thanks to the ability of actors to address distribution, autonomy of control, and asynchronous communication: namely, it is convenient to view the pervasive cyberspace as an environment densely inhabited by mobile situated actors. But how can an actor-centric development approach be fruitfully used to engineer a complex coordination strategy, where a myriad of devices/actors performs adaptive distributed sensing/processing/acting?
Aggregate computing has been proposed as an emerging paradigm that faces this general problem by adopting a global, system-level stance, allowing to specify and functionally compose collective behaviours by operating on diffused data structures, known as “computational fields”. In this paper, we develop on the idea of integrating the actor model and aggregate computing, presenting a software framework where declarative global-level system specifications are automatically turned into an underlying system of Scala/Akka actors carrying complex coordination tasks involving large sets of devices spread over the pervasive computing system
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
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
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