Model round-trip engineering

In the quest for shorter time-to-market, higher quality and reduced cost, model-driven software development has emerged as a promising approach to software engineering. The central idea is to promote models to first-class citizens in the development process. Starting from a set of very abstract models in the early stage of the development, they are refined into more concrete models and finally, as a last step, into code. As early phases of development focus on different concepts compared to later stages, various modelling languages are employed to most accurately capture the concepts and relations under discussion. In light of this refinement process, translating between modelling languages becomes a time-consuming and error-prone necessity. This is remedied by model transformations providing support for reusing and automating recurring translation efforts. These transformations typically can only be used to translate a source model into a target model, but not vice versa. This poses a problem if the target model is subject to change. In this case the models get out of sync and therefore do not constitute a coherent description of the software system anymore, leading to erroneous results in later stages. This is a serious threat to the promised benefits of quality, cost-saving, and time-to-market. Therefore, providing a means to restore synchronisation after changes to models is crucial if the model-driven vision is to be realised. This process of reflecting changes made to a target model back to the source model is commonly known as Round-Trip Engineering (RTE). While there are a number of approaches to this problem, they impose restrictions on the nature of the model transformation. Typically, in order for a transformation to be reversed, for every change to the target model there must be exactly one change to the source model. While this makes synchronisation relatively “easy”, it is ill-suited for many practically relevant transformations as they do not have this one-to-one character. To overcome these issues and to provide a more general approach to RTE, this thesis puts forward an approach in two stages. First, a formal understanding of model synchronisation on the basis of non-injective transformations (where a number of different source models can correspond to the same target model) is established. Second, detailed techniques are devised that allow the implementation of this understanding of synchronisation. A formal underpinning for these techniques is drawn from abductive logic reasoning, which allows the inference of explanations from an observation in the context of a background theory. As non-injective transformations are the subject of this research, there might be a number of changes to the source model that all equally reflect a certain target model change. To help guide the procedure in finding “good” source changes, model metrics and heuristics are investigated. Combining abductive reasoning with best-first search and a “suitable” heuristic enables efficient computation of a number of “good” source changes. With this procedure Round-Trip Engineering of non-injective transformations can be supported

Scaling choreography modelling for B2B value-chain analysis

The modelling of B2B scenarios focuses on conversations between key partners to establish a common business context for their collaboration. With the prevalence of Web services, attention has turned to service choreographies as a means of message exchange ordering between collaborating participants, from a global (or shared) understanding. As such, the message ordering in a choreography model can then be used to determine the message ordering behaviour of each participant's process. In this paper, we extend the suitability of choreography modelling for the early phase of analysis, where the participants and the nature of interactions develops under the flux of requirements acquisition. In particular, we develop a structural view of interactions and stepwise refinement, leading to behavioural considerations, reminiscent of classical techniques. In addition, we introduce contextualisation of intent behind message exchanges in the form of speech acts. This, we show, can be used to automatically detect conflicts in conversations, in the business sense, namely negotiation or provision breakdowns - prior to technical implementations of choreographies. Model abstraction and refinement is based on Semantic Object Model (SOM), and a mapping to the Business Process Modelling Notation (BPMN) is shown

Towards model round-trip engineering : an abductive approach

Providing support for reversible transformations as a basis for round-trip engineering is a significant challenge in model transformation research. While there are a number of current approaches, they require the underlying transformation to exhibit an injective behaviour when reversing changes. This however, does not serve all practical transformations well. In this paper, we present a novel approach to round-trip engineering that does not place restrictions on the nature of the underlying transformation. Based on abductive logic programming, it allows us to compute a set of legitimate source changes that equate to a given change to the target model. Encouraging results are derived from an initial prototype that supports most concepts of the Tefkat transformation language \u

Model Synchronisation: Definitions for Round-Trip Engineering

In a model-centric software development environment, a multitude of different models are used to describe a software system on different abstraction layers and from different perspectives. Following the MDA vision, model transformation is used to support the gradual refinement from abstract models into more concrete models. However, target \ud models do not stay untouched but may be changed due to maintenance work or evolution of the software. Therefore, in order to preserve a coherent description of the whole system, it is necessary to propagate certain changes to a target model back to the source model. However, as transformations in general are partial and not injective, they cannot be easily reversed to propagate changes. This paper presents a formal definition of round-trip engineering and the semantics of target changes in the context \ud of partial and non-injective transformations

OCL support in an industrial environment

Abstract. In this paper, we report on our experiences integrating OCL evaluation support in an industrial-strength (meta-)modeling infrastructure. We focus on the approach taken to improve efficiency through what we call impact analysis of model changes to decrease the number of necessary (re-)evaluations. We show how requirements derived from application scenarios have led to design decisions that depart from or resp. extend solutions found in (academic) literature.

SLAC-PUB-15606 A BASELINE DESIGN FOR PEP-X: AN ULTRA-LOW EMITTANCE STORAGE RING ∗

We completed a design of PEP-X [1] as a highbrightness light source that could reside in the existing 2.2km PEP-II tunnel. The design features a hybrid lattice with double bend achromat (DBA) cells in two arcs and theoretical minimum emittance (TME)cells in the remaining four arcs. The baseline design will produce photon beams achieving a brightness of 10 22 (ph/s/mm 2 /mrad 2 /0.1% BW) at 10 keV in a 3.5-m conventional planar undulator. Our study shows that an optimized lattice has adequate dynamic aperture, while accommodating a conventional offaxis injection system. In the paper, we will summarize the results of the study, including the lattice properties, nonlinear dynamics, intra-beam scattering and Touschek lifetime, and collective instabilities. This future light source has a potential to reach high coherence in both transverse dimensions for multi-keV photons and to lase partially in a very long undulator at soft x-ray wavelengths. Achieving these features would make this storage ring-based light source very competitive to a source based on an energy recovery linac (ERL)

A Search-Based and Fault-Tolerant Approach to Concurrent Model Synchronisation

In collaboration scenarios, we often encounter situations in which semantically interrelated models are changed concurrently. Concurrent model synchronization denotes the task of keeping these models consistent by propagating changes between them. This is challenging as changes can contradict each other and thus be in conflict. A problem with current synchronisation approaches is that they are often nondeterministic, i.e., the order in which changes are propagated is essential for the result. Furthermore, a common limitation is that the involved models must have been in a consistent state at some point, and that the applied changes are at least valid for the domain in which they were made. We propose a hybrid approach based on Triple Graph Grammars (TGGs) and Integer Linear Programming (ILP) to overcome these issues: TGGs are a grammar-based means that supplies us with a superset of possible synchronization solutions, forming a search space from which an optimum solution incorporating user-defined preferences can be chosen by ILP. Therefore, the proposed method combines configurability by comprising expert knowledge via TGGs with the flexible input handling of search-based techniques: By accepting arbitrary graph structures as input models, the approach is tolerant towards errors induced during the modelling process, i.e., it can cope with input models which do not conform to their metamodel or which cannot be generated by the TGG at hand. The approach is implemented in the model transformation tool eMoflon and evaluated regarding scalability for growing model sizes and an increasing number of changes