The variety of platforms for describing models of discrete event systems brings about the problem of how these models should be represented in order to be easily shared across platforms (shared for the purposes of model validation, effective execution, model reusing,  or model integration). This study develops and implements the language DEVSML for the representation of the DEVS models. For the description of these models components, I use state diagrams, which are represented by SCXML. Actions and guards of the state diagrams are described using the language Scheme. This study also presents a visual tool for creation of the state diagrams, which is incorporated in the SmallDEVS system. For the Adevs environment, a transformer of the models described by DEVSML is implemented.

Doctor of Philosophy / Department of Computing and Information Sciences / David A. Gustafson / The Unified Modeling Language (UML) has been designed to be a full standard notation for Object-Oriented Modeling. UML 2.0 consists of thirteen types of diagrams: class, composite structure, component, deployment, object, package, activity, use case, state, sequence, communication, interaction overview, and timing. Each one is dedicated to a different design aspect. This variety of diagrams, which overlap with respect to the information depicted in each, can leave the overall system design specification in an inconsistent state. This dissertation presents Super State Analysis (SSA) for analyzing UML multiple state and sequence diagrams to detect the inconsistencies. SSA model uses a transition set that captures relationship information that is not specifiable in UML diagrams. The SSA model uses the transition set to link transitions of multiple state diagrams together. The analysis generates three different sets automatically. These generated sets are compared to the provided sets to detect the inconsistencies. Because Super State Analysis considers multiple UML state diagrams, it discovers inconsistencies that cannot be discovered when considering only a single UML state diagram. Super State Analysis identifies five types of inconsistencies: valid super states, invalid super states, valid single step transitions, invalid single step transitions, and invalid sequences.

yes / This paper introduces a rigorous framework for function modelling of complex multi-disciplinary systems based on the System State Flow Diagram (SSFD). The work addresses the need for a consistent methodology to support solution neutral function based system decomposition analysis, facilitating the design, modelling and analysis of complex systems architectures. A rigorous basis for the SSFD is established by defining conventions for states and function definition and representation scheme, underpinned by a critical review of existing literature. A set of heuristics are introduced to support the function decomposition analysis and to facilitate the deployment of the methodology with strong practitioner guidelines. The SSFD heuristics extend the existing framework of Otto and Wood (2001) by introducing a conditional fork node heuristic, to facilitate analysis and aggregation of function models across multiple modes of operation of the system. The empirical validation of the SSFD function modelling framework is discussed in relation to its application to two case studies: (i) a benchmark problem (Glue Gun) set for the engineering design community; and (ii) an industrial case study of an electric vehicle powertrain. Based on the evidence from the two case studies presented in the paper, a critical evaluation of the SSFD function modelling methodology is presented based on the function benchmarking framework established by Summers et al (2013), considering the representation, modelling, cognitive and reasoning characteristics. The significance of this paper is that it establishes a rigorous reference framework for the SSFD function representation and a consistent methodology to guide the practitioner with its deployment, facilitating its impact to industrial practice.

Yes / This article presents the application of the Enhanced Sequence Diagram (ESD) for the analysis of the functionality of a system with shape-changing aspects in the context of its multiple operational modes, considering an active rear spoiler as a case study. The article provides new insights on the ESD support for model-based capture and articulation of functional requirements across multiple operation modes of the same system, with appropriate detail on attributes and metrics, and the alignment of these attributes and metrics in line with the concept of time through scope lines. The article also provides a comprehensive argument and discussion, exemplified based on the case study, for the support that the ESD provides for early systems functional and architecture analysis, within the context of a broader model-based Failure Mode Analysis methodology.