1,720,956 research outputs found
The automated translation of integrated formal specifications into concurrent programs
Full text linkThe PROB model checker [LB03] provides tool support for an integrated formal specification approach, which combines the state-based B specification language [Abr96] with the event-based process algebra CSP [Hoa78]. The JCSP package [WM00b] presents a concurrent Java implementation for CSP/occam.In this thesis, we present a developing strategy for implementing such a combined specificationas a concurrent Java program. The combined semantics in PROB is flexible and ideal for model checking, but is too abstract to be implemented in programming languages. Also, although the JCSP package gave us significant inspiration for implementing formal specifications in Java, we argue that it is not suitable for directly implementing the combined semantics in PROB. Therefore, we started with defining a restricted semantics from the original one in PROB. Then we developed a new Java package, JCSProB, for implementing the restricted semantics in Java. The JCSProB package implements multi-way synchronization with choice for the combined B and CSP event, as well as a new multi-threading mechanism at process level. Also, a GUI sub-package isdesigned for constructing GUI programs for JCSProB to allow user interaction and runtime assertion checking. A set of translation rules relates the integrated formal modelsto Java and JCSProB, and we also implement these rules in an automated translation tool for automatically generating Java programs from these models.To demonstrate and exercise the tool, several B/CSP models, varying both in syntactic structure and behavioural properties, are translated by the tool. The models manifest the presence and absence of various safety, deadlock, and fairness properties; the generated Java code is shown to faithfully reproduce them. Run-time safety and fairness assertion checking is also demonstrated. We also experimented with composition and decomposition on several combined models, as well as the Java programs generated from them. Composition techniques can help the user to develop large distributed systems, and can significantly improve the scalability of the development of the combined models of PROB
Java implementation platform for the integrated state- and event-based specification in PROB
Full text linkPROB is an animation and model checking tool, which supports integrated event- and state-based specifications combining B and CSP. We present an initial strategy for implementing the combined specification model as a concurrent Java program. Our Java implementation for the combined B and CSP model uses a similar approach to that of JCSP. The restricted operational semantics for the integrated B and CSP model in PROB is defined. Then a new Java package, JCSProB, is developed for implementing the semantics. The new package supports external choice with multi-way synchronization, and introduces an improved multi-threading implementation from JCSP
Automatic Translation from Combined B and CSP specification to Java Programs
No full textA recent contribution to the formal specification and verification of concurrent systems is the integration of the state- and event-based approaches B and CSP, specifically in the ProB model checking tool. At the implementation end of the development, concurrent programming in Java remains a demanding and error-prone activity, because of the need to verify critical properties of safety and liveness as well as functional correctness. This work contributes to the automated development of concurrent Java programs from such integrated specifications. The JCSP package was originally designed as a proven clean Java concurrency vehicle for the implementation of certain CSP specifications. In the context of best current Java concurrent programming practice, we extend the original JCSP package to support the integrated B and CSP specification by implementing new channel classes. We propose rules for the automated translation of the integrated specification to multi-threaded Java using the extended JCSP channel classes. We briefly present a prototype translation tool which extends ProB, with a worked example, and conclude with a strategy for formally verifying the translation
JCSProB: Implementing Integrated Formal Specifications in Concurrent Java
No full textThe ProB model checker provides tool support for an integrated formal specification approach, which combines the classical state-based B language with the event-based process algebra CSP. In this paper, we present a developing strategy for implementing such a combined ProB specification as a concurrent Java program. A Java implementation of the combined B and CSP model has been developed using a similar approach to JCSP. A set of translation rules relates the formal model to its Java implementation, and we also provide a translation tool JCSProB to automatically generate a Java program from a ProB specification. To demonstrate and exercise the tool, several B/CSP models, varying both in syntactic structure and behavioural/concurrency properties, are translated by the tool. The models manifest the presence and absence of various safety, deadlock, and bounded fairness properties; the generated Java code is shown to faithfully reproduce them. Run-time safety and bounded fairness checking is also demonstrated. The Java programs are discussed to demonstrate our implementation of the abstract B/CSP concurrency model in Java. In conclusion we consider the effectiveness and generality of the implementation strategy
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
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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