1,720,973 research outputs found
Performance indices to characterise concurrent applications: experimenting GSPN evaluation techniques in plant automation
No full textStochastic Petri net evaluation techniques in plant automation: Tuning performance indices for distributed applications
No full textWe report the results of an investigation aiming at experimenting the use of Generalized Stochastic Petri Nets (GSPN), a formal method which allows to model a concurrent application with an explicit representation of timing constraints, and to evaluate its performance over a target parallel architecture. We focus on the definition and use of a set of indices suitable to characterise an application in terms of its performance and to support its mapping over a parallel architecture, guided by the training over a case study taken from the ENEL R&D activity in real time plant automation. The effort spent to extend and to bring a relatively consolidated theory (GSPN) near to the industrial user needs, may be seen as the first original contribution of the paper. © 1995 IEEE
Using SWN nets to specify and analyze FT mechanisms adopted in electric plant automation
No full textThe increasing complexity of automation systems, which combine high functional, real-time and fault-tolerant requirements, demands for techniques and tools to support design choices and validation phases. In this paper we investigate the possibility of using a class of high-level stochastic Petri nets known as stochastic well-formed nets (SWN) as a framework for specifying and deriving quantitative properties of FT mechanisms used in (electric) plant automation. A temporal redundancy technique adopted in several plants is taken as a case-study
SWN nets as a framework for the specification and the analysis of FT techniques adopted in electric plant automation
No full textThe use of formal methods for specification and analysis of dependable systems is considered a promising opportunity to support the evaluation of critical issues since the early design phases. Stochastic Petri nets can play an important role not only for the specification of functional issues of a system, but also for the predictive evaluation of performance and dependability properties. In this paper we investigate the possibility of using Stochastic Well-formed Nets (SWN) as a framework for specifying, validating and evaluating fault tolerance mechanisms used in plant automation. A temporal redundancy technique currently adopted in several electric plants to deal with transient faults is taken as a case-study. The peculiar feature of SWNs is the capability of directly generating an aggregated state space thus allowing for efficient model analysis
Performance Prediction of a Reconfigurable High Voltage Substation Simulator: A Case Study Using SWN
No full textThis paper presents the modeling and performance evaluation of a high voltage substation simulator with real time constraints, running on a multiprocessor architecture.
The Stochastic Well-formed Net models of the simulator and of the target multiprocessor have been designed with the goal of providing guidelines as well as automatic tools for the generalization to several software and hardware configurations as well as mappings.
Quantitative results have been obtained using the simulation facilities (both ordinary and symbolic) offered by the GreatSPN2.0 tool
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
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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