Towards Language-Oriented Modeling

In this habilitation à diriger des recherches (HDR), I review a decade of research work in the fields of Model-Driven Engineering (MDE) and Software Language Engineering (SLE). I propose contributions to support a language-oriented modeling, with the particular focus on enabling early validation & verification (V&V) of software-intensive systems. I first present foundational concepts and engineering facilities which help to capture the core domain knowledge into the various heterogeneous concerns of DSMLs (aka. metamodeling in the small), with a particular focus on executable DSMLs to automate the development of dynamic V&V tools. Then, I propose structural and behavioral DSML interfaces, and associated composition operators to reuse and integrate multiple DSMLs (aka. metamodeling in the large).In these research activities I explore various breakthroughs in terms of modularity and reusability of DSMLs. I also propose an original approach which bridges the gap between the concurrency theory and the algorithm theory, to integrate a formal concurrency model into the execution semantics of DSMLs. All the contributions have been implemented in software platforms — the language workbench Melange and the GEMOC studio – and experienced in real-world case studies to assess their validity. In this context, I also founded the GEMOC initiative, an attempt to federate the community on the grand challenge of the globalization of modeling languages

Towards an Object-Oriented Language for Cognitive Modeling

This paper describes work towards an object-oriented language for cognitive modeling. Existing modeling languages (such as C, LISP and Prolog) tend to be far removed from the techniques employed by psychologists in developing their theories. In addition, they encourage the confusion of implementation detail necessary for computational completeness with theoretically motivated aspects. The language described here (OOS) has been designed so as to facilitate this theory/implementation separation, while at the same time simplifying the modeling process for computationally non-sophisticated users by providing a set of classes of basic "cognitive" objects. The object classes are tailored to the implementation of functionally modular cognitive models in the box/arrow style. The language is described (in terms of its execution model and its basic classes) before a sketch is given of a simple production system which has been implemented within the language. W e conclude with a discussion of on-going work aimed at extending the coverage of the language and further simplifying the modeling process

Transformation of UML Behavioral Diagrams to Support Software Model Checking

Unified Modeling Language (UML) is currently accepted as the standard for modeling (object-oriented) software, and its use is increasing in the aerospace industry. Verification and Validation of complex software developed according to UML is not trivial due to complexity of the software itself, and the several different UML models/diagrams that can be used to model behavior and structure of the software. This paper presents an approach to transform up to three different UML behavioral diagrams (sequence, behavioral state machines, and activity) into a single Transition System to support Model Checking of software developed in accordance with UML. In our approach, properties are formalized based on use case descriptions. The transformation is done for the NuSMV model checker, but we see the possibility in using other model checkers, such as SPIN. The main contribution of our work is the transformation of a non-formal language (UML) to a formal language (language of the NuSMV model checker) towards a greater adoption in practice of formal methods in software development.Comment: In Proceedings FESCA 2014, arXiv:1404.043

Distribution of the Object Oriented Databases. A Viewpoint of the MVDB Model's Methodology and Architecture

In databases, much work has been done towards extending models with advanced tools such as view technology, schema evolution support, multiple classification, role modeling and viewpoints. Over the past years, most of the research dealing with the object multiple representation and evolution has proposed to enrich the monolithic vision of the classical object approach in which an object belongs to one hierarchy class. In particular, the integration of the viewpoint mechanism to the conventional object-oriented data model gives it flexibility and allows one to improve the modeling power of objects. The viewpoint paradigm refers to the multiple descriptions, the distribution, and the evolution of object. Also, it can be an undeniable contribution for a distributed design of complex databases. The motivation of this paper is to define an object data model integrating viewpoints in databases and to present a federated database architecture integrating multiple viewpoint sources following a local-as-extended-view data integration approach.object-oriented data model, OQL language, LAEV data integration approach, MVDB model, federated databases, Local-As-View Strategy.

An Approach Based on Maintainability Criteria for Building Aspect-Oriented Software Design Model

Software modeling is an important activity for maintenance since it can facilitate the software comprehension as well as the understanding of its activities towards evolution, correction and adaptation. In this sense, maintainability and its subcharacteristics as presented in the ISO/IEC 9126 standard should be incorporated 0to the artifacts produced in the modeling activity aiming at designing software with characteristics that render its maintenance less costly. Especially in non-trivial software, such as those that are aspect-oriented, the research on maintenance process considering it during the software development is remarkable. These categories of software aim at maintainability and reusability since they provide the separation of concerns. Thus, seeking to reduce the transition effort to the artifacts generated during the Aspect-Oriented Software Development among the different abstraction levels, this paper presents a proposal of maintainability criteria for building aspect-oriented software design models based on the Maintainability Criteria for Implementation Models, on the aSideML language modeling conventions and on the ISO/IEC 9126 standard

An Abstract Metamodel for Aspect Languages

AOP is widely accepted as a language concept to improve separation of concerns, but it has often been pointed out that an encompassing theory of aspect composition is as yet missing. We define an abstract metamodel in which we capture the elements that we believe are the typical aspect oriented programming concepts. Also, these elements are crucial to the understanding of the semantics of AOP language constructs. We intend the metamodel to be a first step towards modeling and comparing AOP languages, as well as a foundation to define the semantics of AOP languages

An Imitation Learning Approach to Unsupervised Parsing

Recently, there has been an increasing interest in unsupervised parsers that optimize semantically oriented objectives, typically using reinforcement learning. Unfortunately, the learned trees often do not match actual syntax trees well. Shen et al. (2018) propose a structured attention mechanism for language modeling (PRPN), which induces better syntactic structures but relies on ad hoc heuristics. Also, their model lacks interpretability as it is not grounded in parsing actions. In our work, we propose an imitation learning approach to unsupervised parsing, where we transfer the syntactic knowledge induced by the PRPN to a Tree-LSTM model with discrete parsing actions. Its policy is then refined by Gumbel-Softmax training towards a semantically oriented objective. We evaluate our approach on the All Natural Language Inference dataset and show that it achieves a new state of the art in terms of parsing $F$-score, outperforming our base models, including the PRPN.Comment: ACL201

Advanced techniques in reliability model representation and solution

The current tendency of flight control system designs is towards increased integration of applications and increased distribution of computational elements. The reliability analysis of such systems is difficult because subsystem interactions are increasingly interdependent. Researchers at NASA Langley Research Center have been working for several years to extend the capability of Markov modeling techniques to address these problems. This effort has been focused in the areas of increased model abstraction and increased computational capability. The reliability model generator (RMG) is a software tool that uses as input a graphical object-oriented block diagram of the system. RMG uses a failure-effects algorithm to produce the reliability model from the graphical description. The ASSURE software tool is a parallel processing program that uses the semi-Markov unreliability range evaluator (SURE) solution technique and the abstract semi-Markov specification interface to the SURE tool (ASSIST) modeling language. A failure modes-effects simulation is used by ASSURE. These tools were used to analyze a significant portion of a complex flight control system. The successful combination of the power of graphical representation, automated model generation, and parallel computation leads to the conclusion that distributed fault-tolerant system architectures can now be analyzed