International audience

Abstract Modern systems are increasingly connected and more integrated with other existing systems, giving rise to systems‐of‐systems (SoS). An SoS consists of a set of independent, heterogeneous systems that interact to provide new functionalities and accomplish global missions through emergent behavior manifested at runtime. The distinctive characteristics of SoS, when contrasted to traditional systems, pose significant research challenges within software engineering. These challenges motivate the need for a paradigm shift and the exploration of novel approaches for designing, developing, deploying, and evolving these systems. The International Workshop on Software Engineering for Systems‐of‐Systems (SESoS) series started in 2013 to fill a gap in scientific forums addressing SoS from the software engineering perspective, becoming the first venue for this purpose. This article presents a study aimed at outlining the evolution and future trajectory of software engineering for SoS based on the examination of 57 papers spanning the 11 editions of the SESoS workshop (2013–2023). The study combined scoping review and scientometric analysis methods to categorize and analyze the research contributions concerning temporal and geographic distribution, topics of interest, research methodologies employed, application domains, and research impact. Based on such a comprehensive overview, this article discusses current and future directions in software engineering for SoS.

A key challenge in automating vehicle driving maneuvers is to address uncertainty, mainly related to the interactions between the ego vehicle and all the surrounding traffic as well as the road infrastructure. In the case of an overtaking maneuver, the neighboring vehicles include the vehicle(s) moving in front of the ego vehicle - in particular, the vehicle(s) to be overtaken - and possibly other vehicles moving in the adjacent lane. In that case, the underlying research question is: how a driving automation system of an ego vehicle shall deal with occurring uncertainties to safely perform overtaking maneuvers, knowing that each of its neighboring vehicles is managerially and operationally independent, their disposition has been evolutionarily formed, and by their interactions, they jointly raise emergent behaviors. In fact, together, these vehicles compose a System-of-Systems (SoS). Recently, a novel formal language, called Fuzzy SosADL, has been specially conceived for modeling opportunistic SoS, while mastering uncertainty and interactions under uncertainty. This paper presents a case study of Fuzzy SosADL, in terms of Fuzzy Mediating Control Systems for safely supporting vehicle overtaking maneuvers in two-way roads, one of the hardest applications of driving automation systems.

International audience

The Ambient Assisted Living (AAL) domain aims to support the daily life activities of elders, patients with chronic conditions or disabled people, with a focus on ICT (Informatics and Communication Technologies). Important advances in AAL software systems have been already made, assisting people in their home, work, and social environments. Because of their critical nature, these systems must be developed focused on their quality. Hence, quality attributes (QAs), such as safety, reliability, and security, must be identified and well defined to successfully achieve the system purposes. However, there is not a set of QAs specific for AAL systems, hence, new systems have been developed based on general standards, such as ISO/IEC 25010, or based on particular experiences. This paper introduces the QM4AAL, a quality model (QM) for AAL systems. The QM4AAL was established and evaluated based on evidence from several published works found through conduction of a systematic mapping study. As result, the QM4AAL details QAs requirements, adaptive (e.g., self-configuring or situation-aware) or static properties, and stakeholders of AAL systems and their constituents systems (e.g., activity monitoring or health status monitoring systems). We intend this QM can orient the design and assessment of current and future AAL systems.

Systems-of-Systems (SoS) refer to large, complex, and software-intensive systems, resulted from the interoperability among heterogeneous, independent constituent systems. The main purpose of SoS is to perform tasks that could not be achieved by these constituents separately; besides, unique SoS characteristics impose new challenges to their development processes. We conducted a Systematic Mapping to identify initiatives, trends, and challenges in the SoS development and, as a result, 32 initiatives were identified. We also evaluated these initiatives with regard to the adherence to the technical processes of IEEE/ISO/IEC 15288:2015 and to the software implementation essential processes of IEEE/ISO/IEC 12207:2008. In general, these initiatives emphasize artifacts in the early stages of the development processes, addressing mainly requirements and architecture. Moreover, 17 of them emphasize the testing activity. We also summarized the SoS characteristics addressed in the studies and discuss the main trends and challenges.

Software-intensive systems are often independently developed, operated, managed, and evolved. Progressively, communication networks have enabled these independent systems to interact, yielding a new kind of complex system, i.e. a system that is itself composed of systems, the so-called System-of-Systems (SoS). By its complex nature, SoS exhibits emergent behaviors. Nowadays, none of the Architecture Description Languages (ADLs), which have been developed for modeling the architectural behavior of single software-intensive systems, has the expressive power to formally describe the architectural behavior of Software-intensive SoSs. For addressing this research challenge, we propose a novel ADL, called SosADL, specially conceived for formally describing the architecture of Software-intensive SoSs. It embodies SoS architectural concepts and constructs encompassing the formal description of software architectures from both the structural and behavioral viewpoints. This paper presents SosADL focusing on the description of the architectural behavior of Software-intensive SoSs. It describes SosADL from its behavioral viewpoint enabling to specify independent systems, mediators among these systems, coalitions of mediated systems, and the architectural conditions that enforce the production of emergent SoS behaviors. It illustrates SosADL through an excerpt of a real application for architecting a Flood Monitoring and Emergency Response SoS.

Missions represent a key concern in the development of Systems-of-Systems (SoS) since they are related to both capabilities of constituent systems and interactions among these systems that contribute to the accomplishment of global goals of the SoS. In a mission-oriented approach to design software-intensive SoS, the activity towards the concretization of the mission model is its refinement to an architectural model. This paper addresses this synergetic relationship between mission and architectural models. As main contribution, we introduce a model-based refinement process supported by model-to-model transformations intended to apply mission models represented in mKAOS, a language to model missions, for automatically generating architecture descriptions in SosADL, a formal language to describe SoS software architectures.

Software architecture description has been the subject of intensive research in the last two decades resulting in different formal ADLs applied for describing static and dynamic software architectures of (often large) single systems. However, none of these ADLs has the expressive power for formally describing the evolutionary architecture of a System-of-Systems (SoS). Recently, a novel ADL, called SosADL, was specially conceived for formally describing the software architecture of SoSs. This paper presents a case study demonstrating how SosADL can be applied to formally describe the architecture of a critical Software-intensive SoS, the Urban River Monitoring SoS deployed in the Monjolinho river crossing the city of Sao Carlos.

SysADL is a SysML profile for describing architectures using the well-known and consolidated abstractions from the software architecture community. It defines a systematic use of SysML specifically supporting architecture descriptions. For this purpose, it encompasses three integrated viewpoints: structural, behavioral, and executable. This paper focuses on the behavioral viewpoint that relies on the SysML activity and parametric diagrams to capture the behavior of atomic and composite architectural elements. We use an air-conditioning systems as a case study to illustrate SysADL behavioral views and investigate the applicability of SysADL through a controlled experiment.

Systems-of-Systems (SoS) refer to a new class of software-intensive systems, where their constituent systems work cooperatively in order to fulfill specific missions. Characterized by managerial and operational independence, geographic distribution, evolutionary development, and emergent behavior, SoS bring substantial challenges to the software engineering area. SESoS 2015, held in Florence, Italy, on May 17, 2015, as a joint workshop of the 37th International Conference on Software Engineering (ICSE), provided a forum to exchange ideas and experiences, analyze current research and development issues, discuss promising solutions, and to explore inspiring visions for the future of Software Engineering (SE) for SoS.

Dynamic software architectures are those that describe how components and connectors can be created, interconnected, and/or removed during system execution. Most existing architecture description languages (ADLs) provide a limited support to expressively describe these architectures and entail architectural mismatches and inconsistencies between architecture and implementation due to their decoupling from implementation. In this paper, we introduce the dynamic reconfiguration support provided by π-ADL, a formal, well-founded theoretically language for describing dynamic software architectures under structural and behavioral viewpoints. π-ADL provides architectural-level primitives for specifying programmed dynamic reconfigurations, i.e., Foreseen changes described at design time and triggered at runtime. In addition, π-ADL allows enacting dynamic reconfiguration by means of: (i) an exogenous approach, in which it is possible to control all elements of the software architectures and to apply the changes on the whole structure, and (ii) an endogenous approach, in which the architectural elements can manage dynamic reconfiguration actions. Furthermore, π-ADL is integrated with the Go programming language, thus enabling to automatically generate implementation code from architectural descriptions, thus tackling the existing gap between them. We hereby use a real-world flood monitoring system as an illustrative example of how to describe dynamic software architectures in π-ADL and automatically generate source code in Go.

Software systems have become increasingly large and complex, often resulting from the integration of several operationally independent systems, thus leading to a new class of systems called Systems-of-Systems (SoS). Moreover, SoS have currently become essentially software-dependent systems, thus arising the Software-intensive Systems-of-Systems (SiSoS). However, in spite of their relevance, there is a lack of a common understanding of what exactly SiSoS are, their characteristics and types, as well as other elements that surround them. In this context, the main contribution of this work is to provide a conceptual model that provides a comprehensive understanding about them. For this purpose, we have extended the ISO/IEC/IEEE 42010 International Standard by considering related studies and previous taxonomies about SoS. In order to illustrate the use of our model, two software-intensive systems were analyzed and discussed. By establishing a common understanding about SiSoS, results achieved until now have showed us that this model can provide an important support to the research on SiSoS and, as a consequence, it can contribute to the development of these systems.

Reference architectures have emerged as a special type of software architecture that achieves well-recognized understanding of specific domains, promoting reuse of design expertise and facilitating the development, standardization, and evolution of software systems. Because of their advantages, several reference architectures have been proposed and have been also successfully used, including in the industry. However, the most of these architectures are still built using an ad-hoc approach, lacking of a systematization to their construction. If existing, these approaches could motivate and promote the building of new architectures and also support evolution of existing ones. In this scenario, the main contribution of this paper is to present the evolution of ProSA-RA, a process that systematizes the design, representation, and evaluation of reference architectures. ProSA-RA has been already applied in the establishment of reference architectures for different domains and this experience was used to evolve our process. In this paper, we illustrate an application of ProSA-RA in the robotics domain. Results achieved through the use of ProSA-RA have showed us that it is a viable, efficient process and, as a consequence, it could contribute to the reuse of knowledge in several applications domains, by promoting the establishment of new reference architectures.

A key aspect of the design of any software system is its architecture. From the perspective of dependability, an effective architecture aims to build fault-free systems, i.e. ensuring fault avoidance. At the architecture level, fault avoidance is achieved by formally describing the structure and behaviour of software systems enabling to check their correctness. Therefore, a software architecture description should provide a formal specification of the architecture in terms of components and connectors and how they behave and are composed together. Further, a dynamic software architecture must provide a specification of how the architecture of the software system can change at runtime. Enabling specification of dynamic architectures is a large challenge for an architecture description language (ADL). This paper presents how Pi-ADL, a novel ADL that has been designed in the ArchWare European Project, can be used for specifying dynamic architectures through a case study.

The Business Process Models and grid-enabled Service Oriented Architecture (BPMSOA) framework facilitates the enactment of a business process using application domain specific grid services. In this paper, we use a role-based instance of BPMSOA to enact the Search process of the digital libraries domain. Furthermore, in order to find the extent to which the BPMSOA contributes in bridging the gap between business process models and grid systems, an evaluation framework has been defined. Using this evaluation framework the structural, flow and informational translations are verified at different levels of the BPMSOA for correctness and consistency. In addition, the evaluation framework is used to validate the behavioural correctness of the process being enacted. The BPMSOA evaluation using the Search process reveals that the step by step model translations enable the Search process model to be enacted using Pi-Architectural Description Language (π-ADL) and to be executed using application domain specific grid services as a step towards bridging the gap between business process models and grid-enabled SOA (GSOA).

The CERN’s Technical Control Room has implemented a method used to define the monitoring information that is necessary to efficiently restart an accelerator after a major breakdown [1]. This method is the basis for the development of a set of monitoring views, which must follow accurate rules in order to be easily understood and efficiently used by the control room operators.

The design of intelligent instruments, i.e., sensors and actuators, is a complex field. Competences in physics, mechanics, and computing sciences are needed for this design, and strong constraints coming from the instrument hardware or the chosen fieldbus have to be respected. One of the sensitive issues of the design is that the software design has to be made by instrument designers who are domain specialists, but not software experts. Such a designer is able to easily design the hardware part of the intelligent instrument but not the software part.

Software that cannot evolve is condemned to atrophy: it cannot accommodate the constant revision and re-negotiation of its business goals nor intercept the potential of new technology. To accommodate change in software systems, we have defined an active software architecture to be: dynamic in that the structure and cardinality of the components and interactions are changeable during execution; updatable in that components can be replaced; decomposable in that an executing system may be (partially) stopped and split up into its components and interactions; and reflective in that the specification of components and interactions may be evolved during execution. Here we describe the facilities of the ArchWare architecture description language (ADL) for specifying active architectures. The contribution of the work is the unique combination of concepts including: a /spl pi/-calculus based communication and expression language for specifying executable architectures; hyper-code as an underlying representation of system execution that can be used for introspection; a decomposition operator to incrementally break up executing systems; and structural reflection for creating new components and binding them into running systems.

This paper presents an architecture description language, called /spl pi/-SPACE, designed to cope with requirements on evolving software architectures. /spl pi/-SPACE provides constructs for describing architectures based on the /spl pi/-calculus. It supports the adding, replacing and removing of components and connectors in an evolving software system. Applications of /spl pi/-SPACE are motivated by work on the relationships between business processes (including software development) and the software systems which support them. Businesses need flexible software that enhances their ability to adapt and survive in changing organizations.