618 research outputs found
VERTO: a visual notation for declarative process models
Declarative approaches to business process modeling allow to represent loosely-structured
(declarative) processes in flexible scenarios as a set of constraints on the allowed flow of
activities. However, current graphical notations for declarative processes are difficult to
interpret. As a consequence, this has affected widespread usage of such notations, by
increasing the dependency on experts to understand their semantics. In this paper, we
tackle this issue by introducing a novel visual declarative notation targeted to a more
understandable modeling of declarative processes
A controlled experiment for the empirical evaluation of safety analysis techniques for safety-critical software
Context: Today's safety critical systems are increasingly reliant on
software. Software becomes responsible for most of the critical functions of
systems. Many different safety analysis techniques have been developed to
identify hazards of systems. FTA and FMEA are most commonly used by safety
analysts. Recently, STPA has been proposed with the goal to better cope with
complex systems including software. Objective: This research aimed at comparing
quantitatively these three safety analysis techniques with regard to their
effectiveness, applicability, understandability, ease of use and efficiency in
identifying software safety requirements at the system level. Method: We
conducted a controlled experiment with 21 master and bachelor students applying
these three techniques to three safety-critical systems: train door control,
anti-lock braking and traffic collision and avoidance. Results: The results
showed that there is no statistically significant difference between these
techniques in terms of applicability, understandability and ease of use, but a
significant difference in terms of effectiveness and efficiency is obtained.
Conclusion: We conclude that STPA seems to be an effective method to identify
software safety requirements at the system level. In particular, STPA addresses
more different software safety requirements than the traditional techniques FTA
and FMEA, but STPA needs more time to carry out by safety analysts with little
or no prior experience.Comment: 10 pages, 1 figure in Proceedings of the 19th International
Conference on Evaluation and Assessment in Software Engineering (EASE '15).
ACM, 201
Enhancing declarative process models with DMN decision logic
Modeling dynamic, human-centric, non-standardized and knowledge-intensive business processes with imperative process modeling approaches is very challenging. Declarative process modeling approaches are more appropriate for these processes, as they offer the run-time flexibility typically required in these cases. However, by means of a realistic healthcare process that falls in the aforementioned category, we demonstrate in this paper that current declarative approaches do not incorporate all the details needed. More specifically, they lack a way to model decision logic, which is important when attempting to fully capture these processes. We propose a new declarative language, Declare-R-DMN, which combines the declarative process modeling language Declare-R with the newly adopted OMG standard Decision Model and Notation. Aside from supporting the functionality of both languages, Declare-R-DMN also creates bridges between them. We will show that using this language results in process models that encapsulate much more knowledge, while still offering the same flexibility
VISUAL PPINOT: A Graphical Notation for Process Performance Indicators
Process performance indicators (PPIs) allow the
quantitative evaluation of business processes, providing
essential information for decision making. It is common
practice today that business processes and PPIs are usually
modelled separately using graphical notations for the former
and natural language for the latter. This approach
makes PPI definitions simple to read and write, but it
hinders maintenance consistency between business processes
and PPIs. It also requires their manual translation
into lower-level implementation languages for their operationalisation,
which is a time-consuming, error-prone task
because of the ambiguities inherent to natural language
definitions. In this article, VISUAL PPINOT, a graphical
notation for defining PPIs together with business process
models, is presented. Its underlying formal metamodel
allows the automated processing of PPIs. Furthermore, it
improves current state-of-the-art proposals in terms of
expressiveness and in terms of providing an explicit visualisation
of the link between PPIs and business processes,
which avoids inconsistencies and promotes their co-evolution.
The reference implementation, developed as a
complete tool suite, has allowed its validation in a multiple-
case study, in which five dimensions of VISUAL PPINOT
were studied: expressiveness, precision, automation,
understandability, and traceability.Comisión Interministerial de Ciencia y Tecnología TIN2015-70560-RJunta de Andalucía P12-TIC-186
The Construction of Verification Models for Embedded Systems
The usefulness of verification hinges on the quality of the verification model. Verification is useful if it increases our confidence that an artefact bahaves as expected. As modelling inherently contains non-formal elements, the qualityof models cannot be captured by purely formal means. Still, we argue that modelling is not an act of irrationalism and unpredictable geniality, but follows rational arguments, that often remain implicit. In this paper we try to identify the tacit rationalism in the model construction as performed by most people doing modelling for verification. By explicating the different phases, arguments, and design decisions in the model construction, we try to develop guidelines that help to improve the process of model construction and the quality of models
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