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Formalization of the Operation Recorder based on graph transformation theory
No full textDie Entwicklungen im Bereich des Software Engineering sind in Anbetracht seiner kurzen Geschichte beachtlich. Mit dem erst kürzlichen Aufkommen der modellgetriebenen Entwicklung, welche, wie der Name vermuten lässt, die Modelle in den Mittelpunkt aller Entwicklungsbemühungen stellt, konnten zwar einige der bestehenden Schwierigkeiten code-basierter Entwicklungsprozesse beseitigt werden, jedoch sind damit neue Probleme eingeführt worden. An dieser Stelle sei beispielhaft die Notwendigkeit von Verfahren zur Beschreibung, Steuerung und Verifikation der Evolution von Modellen angeführt. Aufgrund der graph-basierten Struktur von Modellen können bereits gesammelte Erfahrungen und Forschungsergbnisse nur bedingt von der code-basierten zur modellgetriebenen Entwicklung übertragen werden, wodurch die Adaption und Portierung bestehender Lösungen an der praktischen Anwendbarkeit scheitern.Die graph-basierte Struktur von Modellen legt vielmehr die Anwendung von graphtransformationstheoretischen Ansätzen nahe, um die an Modellen durchgeführten Modifikationen mit Graphersetzungsregeln zu beschreiben.Obwohl diese Konzepte und Techniken auf den ersten Blick intuitiv erscheinen, ist die präzise Spezifikation von Graphersetzungsregeln nicht trivial und zeitaufwendig. Dies verlangt nach geeignetem Werkzeugunterstützung und benötigt tiefgehendes Verständnis der zugrundeliegenden Theorie. Aus der Heterogenität der vorhandenen Tools ergibt sich auch die Schwierigkeit, dass deren Tauglichkeit in Bezug auf die Spezifikation von Graphersetzungsregeln und die Unterstützung, die sie den Enwicklerninnen bieten, nicht ohne vorherige eingehende Befassung mit der Materie ersichtlich ist. Zu diesem Zwecke wurde eine Evaluierung existierender Tools durchgeführt, welche den Operation Recorder ins Zentrum weiterer Nachforschungen rückte. Denn im Gegensatz zu allen anderen untersuchten Tools bietet der Operation Recorder eine by-demonstration Umgebung, die es dem Benutzer erlaubt die gewünschten Transformationen beispielhaft zu demonstrieren. Dadurch entfällt die manuelle Erstellung von Transformationen mit dedizierten Modelltransformationsprachen.Der Operation Recorder bietet aber keine präzise, formale Basis, weshalb eine Verifikation der durchgeführten Transformationen nicht möglich ist.Daher wird in dieser Arbeit ein Framework vorgestellt, das die Transformation von attributierten Graphen mit Multiplizitäten, Vererbungs-, und Kompositionsbeziehungen erlaubt. Das Ziel ist es, den Operation Recorder in dieses Framework zu integrieren. In diesem Zusammenhang wird eine konzeptuelle Gegenüberstellung zwischen dem Operation Recorder und der vorgestellten Graphtransformationstheorie angestrebt, um die Äquivalenz und die Austauschbarkeit der jeweiligen Konzepte zu zeigen.Software engineering has come a long way in its short history.With the recent advent of model-driven development, which places models at the center of all development efforts, some of the existing deficiencies of traditional, code-centric software development approaches have been addressed. However, at the same time new problems arose, which require, for example, techniques to describe, control and verify the evolution of models. Drawing from past experiences and findings in the field of code-centric software evolution is only partly feasible due to the inherent graph-based nature of models, which renders the adoption and porting of previously developed solutions for text-based software development impractical.The graph-based nature of models suggests the application of graph transformation-theoretic concepts to models, in order to formally describe their manipulation by means of graph-rewriting rules. Though the concepts and techniques provided by the theory of graph transformation may seem intuitive, the specification of accurate rewriting rules is a non-trivial and time-consuming task, which requires adequate tool support and thorough knowledge of the underlying theory.Unfortunately, due to the heterogeneity of the employed approaches, a tool's capability to specify graph rewriting rules and the degree of assistance offered for this task is hard to determine without prior investigation. Thus, a survey of existing tools was conducted, which revealed the Operation Recorder as a suitable tooling environment. In contrast to all other surveyed tools, it offers a by-demonstration environment, which allows to showcase the intended transformation instead of requiring its manual construction by means of dedicated transformation languages.The Operation Recorder, however, lacks a concise, formal basis which prevents the verification of its transformations. Therefore, a framework to describe attributed graphs with inheritance, composition and multiplicities is presented with the aim to embed the Operation Recorder into this framework. For this purpose, a conceptual alignment is pursued which demonstrates the equivalence and interchangeability of the concepts provided by the Operation Recorder and those provided by the theory of graph transformation
New Model Checking Techniques for Software Systems Modeled with Graphs and Graph Transformations
Get PDFIn today's software, no matter how security and safety critical it may be, defects and failures are common. With the rising complexity of software and our growing dependency on its correct functioning as it permeates our every day life the software development process requires new approaches to integrate formal verification techniques. This thesis presents approaches on efficiently verifying software systems described by model-driven software development artifacts. These artifacts comprise the implementation of the system and consist of both structural and behavioral models. We present two model checking approaches, MocOCL and Gryphon, to verify the temporal specification of a system against its model-based implementation. Central to our approach is the twofold use of graphs to describe the system under verification. First, we describe the admissible static structure of an instance of the system by means of attributed type graphs with inheritance and containment relations, often referred to as metamodel. Second, we represent a state of the system as an object graph that enumerates a system's active objects, the references among them, and their attribute values. A change in the system, e.g., the deletion of an object or the modification of an attribute value, triggers a state change. The behavior of the system is thus described by actions that modify the state of the system. In this thesis we employ graph transformations to model such state-changing actions as they provide suitable means to formally describe modifications on graphs. The specification of the system, on the other hand, is written in our temporal extension of the Object Constraint Language (OCL) that is based on Computation Tree Logic (CTL). A specification written in our CTL extension for OCL, called cOCL, can be verified against a model-based implementation of the system with our explicit-state model checker MocOCL. Gryphon aims to increase the efficiency and scalability of the verification process and implements a symbolic model checking approach, that focuses the verification on safety specifications. The work presented in this thesis also encompasses a survey and a feature-based classification of verification approaches that can be used to verify artifacts of model-driven software development. Methodologically, it provides the motivation for our work on MocOCL and Gryphon. Both our approaches are novel in their own respect; MocOCL for its capability to verify CTL-extended OCL expressions and Gryphon for its use of relational logic to build a symbolic representation of the system that can be verified with any model checker participating in the Hardware Model Checking Competition. Finally, MocOCL and Gryphon are evaluated performance-wise on a set of three representative benchmarks that demonstrate the model checkers' preferred fields of application and its limitations
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
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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