Recommender systems in model-driven engineering

Software and Systems Modeling - Recommender systems are information filtering systems used in many online applications like music and video broadcasting and e-commerce platforms. They are also...     

Towards an advanced model-driven engineering toolbox

Model-driven engineering (MDE) is frequently presented as an important change in software development practice. However, behind this new trend, one may recognize a lot of different objectives and solutions. This paper first studies the multiple facets of MDE and its evolution in the recent period. Several new usage scenarios (i.e., reverse engineering, and models at runtime), which have appeared following the initial forward engineering scenario, i.e., platform-independent model (PIM) to platform-specific model (PSM), are described. Not surprisingly, new applications trigger the need for new tools and the requirement for model engineering platforms evolves correspondingly. We have adapted the AmmA toolbox to these new usages and the result is described herein together with some illustrative examples.     

Automating change evolution in model-driven engineering

The escalating complexity of software and system models is making it difficult to rapidly explore the effects of a design decision. Automating such exploration with model transformation and aspect-oriented techniques can improve both productivity and model quality. The combination of model transformation and aspect weaving provides a powerful technology for rapidly transforming legacy systems from the high-level properties that models describe. Further, by applying aspect-oriented techniques and program transformation, small changes at the modeling level can trigger very large transformations at the source code level. Thus, model engineers can explore alternative configurations using an aspect weaver targeted for modeling tools and then use the models to generate program transformation rules for adapting legacy source code on a wide scale.     

Testing operational transformations in model-driven engineering

Model-driven development is gaining importance in software engineering practice. This increasing usage asks for a new generation of testing tools to verify correctness and suitability of model transformations. This paper presents a novel approach to unit testing QVT operational (QVTO) transformations, which overcomes limitations of currently available tools. Our proposal, called MANTra (Model trANsformation Testing), allows software developers to design test cases directly within the QVTO language and verify them without moving from the transformation environment. MANTra is also available as an eclipse feature that can be easily integrated into established development practice.     

Using DevOps toolchains in Agile model-driven engineering

For model-driven engineering (MDE) to become more Agile, the community needs to embrace development and operations (DevOps) practices. One of the core practices of DevOps is the use of pipelines to enable CI/CD to make teams more Agile and break down the barriers between development and operations with faster deployments. Current MDE tooling is not designed at its core to participate in DevOps pipelines. Consequently this makes the adoption of MDE in industry more difficult. In this article, we cover an industrial experience report describing how we enabled our pipelines using DevOps and MDE.

     

Quality in model-driven engineering: a tertiary study

Model-driven engineering (MDE) is believed to have a significant impact in software quality. However, researchers and practitioners may have a hard time locating consolidated evidence on this impact, as the available information is scattered in several different publications. Our goal is to aggregate consolidated findings on quality in MDE, facilitating the work of researchers and practitioners in learning about the coverage and main findings of existing work as well as identifying relatively unexplored niches of research that need further attention. We performed a tertiary study on quality in MDE, in order to gain a better understanding of its most prominent findings and existing challenges, as reported in the literature. We identified 22 systematic literature reviews and mapping studies and the most relevant quality attributes addressed by each of those studies, in the context of MDE. Maintainability is clearly the most often studied and reported quality attribute impacted by MDE. Eighty out of 83 research questions in the selected secondary studies have a structure that is more often associated with mapping existing research than with answering more concrete research questions (e.g., comparing two alternative MDE approaches with respect to their impact on a specific quality attribute). We briefly outline the main contributions of each of the selected literature reviews. In the collected studies, we observed a broad coverage of software product quality, although frequently accompanied by notes on how much more empirical research is needed to further validate existing claims. Relatively, little attention seems to be devoted to the impact of MDE on the quality in use of products developed using MDE.     

A model-driven engineering framework for embedded systems design

This work presents a Model-Driven Engineering (MDE) framework to improve embedded system design. The framework adopts concepts from MDE for the automatic generation of a control and data flow internal representation, starting from the functional specification of an embedded application described using UML class and sequence diagrams. By means of transformations rules applied on the UML model of the embedded system, an MOF-based (Meta Object Facility is a standard representation for meta-models and models proposed by OMG) internal representation is automatically obtained, which is iteratively mapped into a hardware/software implementation by means of model transformations. This mapping is optimized by a design space exploration (DSE) method based on a categorical graph product. The model transformations have also as input a platform model, which specifies the available hardware, software and interface resources, and produce an implementation model, on which software synthesis, communication synthesis and high-level synthesis algorithms are applied to generate the final implementation. A case study is described to illustrate the application of the framework.     

Teaching model-driven engineering from a relational database perspective

We reinterpret MDE from the viewpoint of relational databases to provide an alternative way to understand, demonstrate, and teach MDE using concepts and technologies that should be familiar to undergraduates. We use (1) relational database schemas to express metamodels, (2) relational databases to express models, (3) Prolog to express constraints and M2M transformations, (4) Java tools to implement M2T and T2M transformations, and (5) Java to execute transformations. Application case studies and a user study illuminate the viability and benefits of our approach.     

Building ubiquitous QoC-aware applications through model-driven software engineering

As every-day mobile devices can easily be equipped with multiple sensing capabilities, ubiquitous applications are expected to exploit the richness of the context information that can be collected by these devices in order to provide the service that is the most appropriate to the situation of the user. However, the design and implementation of such context-aware ubiquitous appplications remain challenging as there exist very few models and tools to guide application designers and developers in mastering the complexity of context information. This becomes even more crucial as context is by nature imperfect. One way to address this issue is to associate to context information meta-data representing its quality. We propose a generic and extensible design process for context-aware applications taking into account the quality of context (QoC). We demonstrate its use on a prototype application for sending flash sale offers to mobile users. We present extensive performance results in terms of memory and processing time of both elementary context management operations and the whole context policy implementing the Flash sale application. The cost of adding QoC management is also measured and appears to be limited to a few milliseconds. We show that a context policy with 120 QoC-aware nodes can be processed in less than 100 ms on a mobile phone. Moreover, a policy of almost 3000 nodes can be instantiated before exhausting the resources of the phone. This enables very rich application scenarios enhancing the user experience and will favor the development of new ubiquitous applications.     

Introduction to the theme section on Agile model-driven engineering

Software and Systems Modeling -     

Adaptable,model-driven security engineering for SaaS cloud-based applications

Software-as-a-service (SaaS) multi-tenancy in cloud-based applications helps service providers to save cost, improve resource utilization, and reduce service customization and maintenance time. This is achieved by sharing of resources and service instances among multiple “tenants” of the cloud-hosted application. However, supporting multi-tenancy adds more complexity to SaaS applications required capabilities. Security is one of these key requirements that must be addressed when engineering multi-tenant SaaS applications. The sharing of resources among tenants—i.e. multi-tenancy—increases tenants’ concerns about the security of their cloud-hosted assets. Compounding this, existing traditional security engineering approaches do not fit well with the multi-tenancy application model where tenants and their security requirements often emerge after the applications and services were first developed. The resultant applications do not usually support diverse security capabilities based on different tenants’ needs, some of which may change at run-time i.e. after cloud application deployment. We introduce a novel model-driven security engineering approach for multi-tenant, cloud-hosted SaaS applications. Our approach is based on externalizing security from the underlying SaaS application, allowing both application/service and security to evolve at runtime. Multiple security sets can be enforced on the same application instance based on different tenants’ security requirements. We use abstract models to capture service provider and multiple tenants’ security requirements and then generate security integration and configurations at runtime. We use dependency injection and dynamic weaving via Aspect-Oriented Programming (AOP) to integrate security within critical application/service entities at runtime. We explain our approach, architecture and implementation details, discuss a usage example, and present an evaluation of our approach on a set of open source web applications.     

Alliance of model-driven engineering with a proof-based formal approach

Model-driven engineering (MDE) promotes the use of models throughout the software development cycle in order to increase abstraction and reduce software complexity. It favors the definition of domain-specific modeling languages (DSMLs) thanks to frameworks dedicated to meta-modeling and code generation like EMF (Eclipse Modeling Framework). The standard semantics of meta-models allows interoperability between tools such as language analysers (e.g., XText), code generators (e.g., Acceleo), and also model transformation tools (e.g., ATL). However, a major limitation of MDE is the lack of formal reasoning tools allowing to ensure the correctness of models. Indeed, most of the verification activities offered by MDE tools are based on the verification of OCL constraints on instances of meta-models. However, these constraints mainly deal with structural properties of the model and often miss out its behavioral semantics. In this work, we propose to bridge the gap between MDE and the rigorous world of formal methods in order to guarantee the correctness of both structural and behavioral properties of the model. Our approach translates EMF meta-models into an equivalent formal B specification and then injects models into this specification. The equivalence between the resulting B specification and the original EMF model is kept by proven design steps leading to a rigorous MDE technique. The AtelierB prover is used to guarantee the correctness of the model’s behavior with respect to its invariant properties, and the ProB model-checker is used to animate underlying execution scenarios which are translated back to the initial EMF model. Besides the use of these automatic reasoning tools in MDE, proved B refinements are also investigated in this paper in order to gradually translate abstract EMF models to concrete models which can then be automatically compiled into a programming language.

     

A model-driven approach for usability engineering of interactive systems

Usability is considered to be one of the most important quality factors that determine the success/failure in the actual use of an interactive system. This can explain the ever-increasing number of publications addressing the problem of usability evaluation. However, most of these proposals only consider usability evaluations after the application is fully implemented and deployed. Some others are based on reviewing usability principles in intermediate artifacts with regard to their conformance with a set of guidelines. Since the traceability between these artifacts and the final application is not well established, performing usability evaluations by considering these artifacts as input may not ensure the usability of the final application. This problem may be alleviated by using a model-driven engineering (MDE) approach due to its intrinsic traceability mechanisms that are established by the transformation processes. The present paper aims to delineate a method for evaluating usability throughout an MDE development life cycle by considering conceptual models as input. To do this, two main contributions are proposed. The first one, called usability-driven model transformation, aims to ensure that an intermediate artifact with the required level of usability is generated. It controls the model transformation process according to a set of usability attributes. The second contribution, called early usability evaluation, performs the usability evaluation from the conceptual models by defining metrics based on conceptual primitives that constitute the conceptual models. This evaluation would be a significant advantage with regard to saving time and resources. The early usability evaluation is empirically validated by comparing the usability measure obtained by our proposal and the level of usability perceived by the end-users.     

Constraint programming for type inference in flexible model-driven engineering

Domain experts typically have detailed knowledge of the concepts that are used in their domain; however they often lack the technical skills needed to translate that knowledge into model-driven engineering (MDE) idioms and technologies. Flexible or bottom-up modelling has been introduced to assist with the involvement of domain experts by promoting the use of simple drawing tools. In traditional MDE the engineering process starts with the definition of a metamodel which is used for the instantiation of models. In bottom-up MDE example models are defined at the beginning, letting the domain experts and language engineers focus on expressing the concepts rather than spending time on technical details of the metamodelling infrastructure. The metamodel is then created manually or inferred automatically. The flexibility that bottom-up MDE offers comes with the cost of having nodes in the example models left untyped. As a result, concepts that might be important for the definition of the domain will be ignored while the example models cannot be adequately re-used in future iterations of the language definition process. In this paper, we propose a novel approach that assists in the inference of the types of untyped model elements using Constraint Programming. We evaluate the proposed approach in a number of example models to identify the performance of the prediction mechanism and the benefits it offers. The reduction in the effort needed to complete the missing types reaches up to 91.45% compared to the scenario where the language engineers had to identify and complete the types without guidance.     

Rigorous identification and encoding of trace-links in model-driven engineering

Model-driven engineering (MDE) involves the construction and manipulation of many models of different kinds in an engineering process. In principle, models can be used in the product engineering lifecycle in an end-to-end manner for representing requirements, designs and implementations, and assisting in deployment and maintenance. The manipulations applied to models may be manual, but they can also be automated??for example, using model transformations, code generation, and validation. To enhance automated analysis, consistency and coherence of models used in an MDE process, it is useful to identify, establish and maintain trace-links between models. However, the breadth and scope of trace-links that can be used in MDE is substantial, and managing trace-link information can be very complex. In this paper, we contribute to managing the complexity of traceability information in MDE in two ways: firstly, we demonstrate how to identify the different kinds of trace-links that may appear in an end-to-end MDE process; secondly, we describe a rigorous approach to defining semantically rich trace-links between models, where the models themselves may be constructed using diverse modelling languages. The definition of rich trace-links allows us to use tools to maintain and analyse traceability relationships.     

Supporting model-driven development using a process-centered software engineering environment

The adoption of Model-Driven Development (MDD) is increasing and it is widely recognized as an important approach for building software systems. In addition to traditional development process models, an MDD process requires the selection of metamodels and mapping rules for the generation of the transformation chain which produces models and application code. In this context, software process tasks should be performed in a specific sequence, with the correct input artifacts to produce the output ones. However, existing support tools and transformation engines for MDD do not have a process-centered focus that addresses different kinds of software process activities, such as application modeling and testing to guide the developers. Furthermore, they do not enable process modeling nor the (semi) automated execution of activities during process enactment. The MoDErNE (Model Driven Process-Centered Software Engineering Environment) uses process-centered software engineering environment concepts to improve MDD process specification and enactment by using a metamodeling foundation. In MoDErNE, a software process model may be enacted several times in different software projects. This paper details the MoDErNE environment, its approach and architecture and also the case studies through which the tool was evaluated.     

rCOS: a formal model-driven engineering method for component-based software

Model-driven architecture (MDA) has become a main stream technology for software-intensive system design. The main engineering principle behind it is that the inherent complexity of software development can only be mastered by building, analyzing and manipulating system models. MDA also deals with system complexity by providing component-based design techniques, allowing independent component design, implementation and deployment, and then system integration and reconfiguration based on component interfaces. The model of a system in any stage is an integration of models of different viewpoints. Therefore, for a model-driven method to be applied effectively, it must provide a body of techniques and an integrated suite of tools for model construction, validation, and transformation. This requires a number of modeling notations for the specification of different concerns and viewpoints of the system. These notations should have formally defined syntaxes and a unified theory of semantics. The underlying theory of the method is needed to underpin the development of tools and correct use of tools in software development, as well as to formally verify and reason about properties of systems in mission-critical applications. The modeling notations, techniques, and tools must be designed so that they can be used seamlessly in supporting development activities and documentation of artifacts in software design processes. This article presents such a method, called the rCOS, focusing on the models of a system at different stages in a software development process, their semantic integration, and how they are constructed, analyzed, transformed, validated, and verified.