Fabian Gilson

Rationale, decisions and alternatives traceability for architecture design

When designing information systems, architects must often deal with many requirements and constraints. Also, many parties may collaborate during design phases. Therefore, the rationale and decisions sustaining the architecture model can be lost if not documented appropriately. However, in order to understand and maintain these systems, we need to have a clear picture of the rationale and decisions behind their designs. To tackle this problem, we propose a design approach combining architecturally significant requirement modelling and architecture modelling. Constraint and Requirement are attached to architectural constructs. And any modification in the architecture model resulting from a decision made in the requirement model is recorded as a model transformation. We present both modelling formalisms and explain how we combine them to increase the traceability of the rationale, design decisions and alternatives as well as the maintainability of information systems.

Towards handling architecture design, variability and evolution with model transformations

Software systems have to face evolving requirements from information system stakeholders, infrastructure modifications, and evolving rationales about the implementation. This increases the rate of migration and redeployment of systems. Recent approaches intend to abstract architectural element specifications from the implementing technology and manage software design through model transformations. Based on an Architecture Description Language integrating infrastructure modelling facilities and a requirement modelling language, the present work manages architecturally significant requirements and infrastructure evolutions by model transformations. Our approach offers support for evolution and variability management tasks as it makes explicit the rationales concerning requirements, infrastructure and implementation alternatives that guide both the software architecture and the infrastructure definition.

A domain specific language for stepwise design of software architectures

Stakeholders have to face requirements in increasing number and complexity. Their translations to system functionalities are often diluted into the overall architecture so that it becomes tricky to undertake future changes. Since information systems are intended to evolve in terms of functionalities and underlying technologies, the link between requirements and design artifacts is primordial. Agile design methods and documentation techniques have emerged in the past years in order to deal with the amount of requirements and to trace the decision process and the rationale sustaining a software model. Also, it is not unusual that numerous technologies with similar purpose are confronted to each other during the design phase. In the present work, we propose an integrated framework combining system requirement definitions, a component-based modeling language and model transformations. Architecturally-significant requirements are explicitly linked to software architecture elements and iteratively refined or implemented by model transformations. Any transformation must be documented, even briefly, and the framework retains the transformations tree. This way, the iterative decision and design processes are completely documented for future reference or modification, i.e, designers can (i) see the mapping between a system requirement and its implementation in the architecture model, (ii) explore design alternatives or apply structural modifications without losing previous versions of the model, and finally (iii), depending on the level of documentation, at least understand partially the reasons why the model is how it is.

Towards User-centric DSLs to Manage IoT Systems

Hidden behind the Internet of Things (IoT), many actors are activelly filling the market with devices and services. From this profusion of actors, a large amount of technologies and APIs, sometimes proprietary, are available, making difficult the interoperability and configuration of systems for IoT technicians. In order to define and manipulate devices deployed in domestic environments, we propose IoTDSL, a Domain-Specific Language meant to specify, assemble and describe the behaviour of interconnected devices. Relying on a high-level rule-based language, users in charge of the deployment of IoT infrastructures are able to describe and combine in a declarative manner structural configurations as well as event-based semantics for devices. This way, language users are freed from technical aspects, playing with high-level representations of devices, while the complexity of the concrete implementation is handled in a dedicated layer where high-level rules are mapped to vendor’s API.

Software architecture design by stepwise model transformations: A comparative case study

Software architecture design is a critical task as lots of requirements can be taken into account on which many decisions can be made. The maintenance and evolution of resulting models often become tricky, even impracticable when their rationale is lost. In a previous work, we introduced a set of languages used in a transformation-centric design method meant to tackle this scattering of requirements and to facilitate further model evolutions. But, we did not provided a formal validation of our proposal yet. The present work depicts a comparative case study we conducted on a group of students. The participants were asked to develop an online book store in two phases, the second one simulating an evolution of the system. We evaluated the functional completeness of the created software as well as the traceability of design decisions and rationale. The participants were also asked to criticize the design method and language they used in a textual report and through a questionnaire. Even if the size of the case study is rather limited, it clearly highlighs the advantages of our approach regarding, among others, its expressiveness and decisions traceability.

Public Debates on the Web

With the advent of social media, any piece of information may be spread all over the world in no time. Furthermore, the vast number of available communication channels makes it difficult to cross-check information that has been (re-)published on different media in real time. In this context where people may express their positions on many subjects, as well as launching new open initiatives, the public needs a mean to gather and compare ideas and opinions in a structured manner. The present paper presents the Open image in new window project, which aims to develop a collaborative platform where opinions, namely arguments, are gathered, analyzed and linked to one another via explicit relations. Open image in new window relies on various Natural Language Processing modules to semi-automatically extract information from the web and propose meaningful visualizations to the platform’s contributors. Furthermore, public actors may be identified and attached to the ideas they publish to create a structured knowledge base where annotated texts, extracted positions and alliances may be identified.

Challenging a Transformation-Wise Architecture Framework in a Comparative Case Study

The maintenance and evolution of software architecture models may become tricky when design rationale is lost over time. Lots of requirements and decisions must be taken into account when dealing with software architecture, such that proper traceability mechanisms should be used all over the system life-cycle. In a previous work, we specified an architectural framework based on domain specific languages meant to address this traceability problem. We now relate a comparative case study we conducted over a simulated project where participants had to develop an online book store in two phases, the second phase imitating a system evolution. We evaluated the functional completeness of the software they built as well as the traceability of design decisions and rationale. The participants were also asked to criticize the design method and language they used in a feedback report and through a questionnaire. Even if the size of the case study is rather limited, it clearly highlights the advantages of our approach regarding, among others, its expressiveness and decisions traceability (The present paper is a revised version of SA design by stepwise transformations [8]).

Transformation-Wise Design of Software Architectures

Stakeholders have to face requirements in increasing number and complexity, and the link between these requirements and design artifacts is primordial. Agile design methods and documentation techniques have emerged in the past years in order to trace the decision process and the rationale sustaining a software model. The present work proposes an integrated framework combining system requirement definitions, component-based models and model transformations. Architecturally significant requirements are explicitly linked to software architecture elements and iteratively refined or implemented by model transformations. Any transformation must be documented, even briefly, and the framework retains the transformations tree. This way, the iterative decision and design processes are completely documented for future reference or modification, i.e., designers can (i) see the mapping between a system requirement and its implementation in the architecture model, (ii) explore design alternatives or apply structural modifications without losing previous versions of the model, and finally (iii) at least understand partially the reasons why the model is how it is.

A Large Scope Transformational Approach for Distributed Architecture Design

Many Architecture Description Languages (ADLs) appeared in order to model complex software solutions. Unfortunately, current modeling approaches do not take into account infrastructure related constraints and do not add non-functional requirements to architecture constructs. This paper describes a transformation-oriented method to design distributed software architectures. Our method is based on an ADL named IODASS. It uses semantically extensible building blocks with qualitative attributes that specify non-functional or infrastructure related requirements.