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This paper reports on experiences of migrating to a new way of documenting software architecture for embedded software development at a company developing software-intensive systems. A lightweight modeling approach using the C4 model for software architecture was adopted, where the architecture diagrams were expressed in PlantUML and stored within Markdown files alongside the code. We describe the problem context and the new approach, and report on a questionnaire survey among the software engineers to elicit their experiences and opinions two years after the introduction of this way of working. The majority of the 48 respondents reported being successful in using the new way of working and see benefits in terms of the better organization of the documentation as stored alongside the code, a clearer process of documenting, better alignment with the code, and ease of use. Engineers report a manageable learning curve but foresee challenges in maintenance and communication of changes across teams working on embedded software, hardware and electronics.

This paper describes the step-by-step processes towards the formalization of a core ontology for missions and capabilities in systems of systems, and the development of a specific system of systems domain ontology from the formalized ontology. The study traces the ontology development process through the SABIOx methodology's requirements, setup, capture, design, and implementation phases. In this process, we demonstrate the core ontology's usability and reusability. Usability refers to the ontology's adequacy for specific use as a reference point for SoS knowledge exploration for development and operational purposes, and reusability refers to the ontology's adequacy for several uses, such as facilitating the understanding of different domain-specific systems of systems. This demonstration is done in three steps: formalization of the core ontology, exploration of the usefulness of this formalization, and development of a domain ontology from the core ontology. These result in: the incorporation of systematic ontology development processes; the application of ontology tools for machine readability; coherence and consistency checking of the ontology artifact; querying support for the ontology knowledge base; and testing of the core knowledge with a domain-specific system of systems. An alignment of these aspects provides different points of view of how a system of systems can be formulated, how the concepts collectively describe the development of an SoS emergent behavior, and how the ontology knowledge base can be explored to support decision frameworks guiding a system of systems.

Software-intensive systems are characterized by intricate interactions, distributed structures, and ongoing evolution posing notable challenges for traceability, change analysis, and decision support. Modeling and versioning practices are widely used to manage this complexity; however, in practice, they are often fragmented, limiting the value that organizations can derive from them. To address this challenge, we map modeling and versioning practices to the benefits they enable, providing a structured framework for practitioners to assess their current practices and identify opportunities for incremental improvement. Building on findings from our previous interview study with multiple companies, together with insights from the literature, we identify four levels of modeling formality, five levels of versioning sophistication, and four categories of benefits, summarized in two mapping tables. Our contributions include a practitioner-oriented roadmap that helps teams reflect on current modeling and versioning practices, anticipate achievable benefits, and identify incremental adjustments that can add value with minimal overhead. An initial validation with industry representatives confirms the practical relevance of the roadmap and highlights its potential to guide structured reflection and improvement of modeling and versioning practices. 

Informal diagrams created in general-purpose diagramming tools are widely used in software architecture because they are quick to produce and easy to share. However, the lack of constraints in such tools often yields inconsistent notations and ad-hoc conventions, which in turn invite misinterpretation when diagrams are read outside their original context. Dedicated modeling languages and environments can mitigate these issues but are frequently resisted due to steep learning curves and disruptive adoption costs. Building on the flexible modeling paradigm, this paper proposes an approach to the lightweight formalization of informal diagrams. Grounded in observed industrial challenges and prior work on flexible modeling, we derive a set of design principles and instantiate them in an approach realized as a Draw.io plugin. We propose an approach that addresses challenges from industrial settings by enabling practitioners to introduce structure incrementally into the informal diagrams they already create, thereby helping resolve notational inconsistency and clarify meaning. Moreover, we show how our approach satisfies the guiding flexible modeling principles by introducing these model-like benefits without compromising the accessibility and speed of informal diagramming as valued in practice. The contribution enhances clarity and consistency within familiar workflows and lays the groundwork for subsequent capabilities such as rapid dissemination of conventions, enterprise-level aggregation, and additional quality checks should organizations choose to adopt them. © 2026, Science and Technology Publications, Lda. All rights reserved.

This study proposes a mapping of a core ontology for missions and capabilities in Systems of Systems to a foundational ontology. It gives a brief overview of the core ontology, compares various foundation ontologies, outlines suitability characteristics, and maps the two ontologies. The mapping process is based on a superclasssubclass mapping. To ensure that the mapping is to the highest level of granularity, this process goes beyond the selected foundation ontology and includes extensions provided by common core ontologies. The outcome of the mapping provides insights into the richness of ontology realism, the connectedness of concepts and ontologies, the consistency this mapping adds to systems engineering efforts by supporting the methodological approach of Model-Based Systems Engineering, and the necessity of conformance in ontological research and implementation. This mapping supports the alignment in knowledge representation by explicitly highlighting the kind of expected input of each core ontology concept. © 2026, Science and Technology Publications, Lda. All rights reserved.

In this article, we present a machine-learning approach to predict the execution time of concurrent applications by leveraging isolated execution times and performance monitoring counters. Through extensive experiments across various application pairs, we explore the challenges of modeling execution time in a concurrent environment. This study highlights three progressively refined models, transitioning from simple neural networks to complex Bayesian-optimized ensemble techniques. A key finding highlights the significant role of interference in execution time variability as shared resource contention leads to deviations from isolated behavior. These insights enhance the understanding of the role of scheduler and application dynamics in concurrent environments. 

Modern software-intensive systems are growing more complex, evolving continuously, and requiring extensive collaboration across diverse domains. Effective documentation and communication of architectural changes are critical to managing the development of such systems. But this task remains challenging due to constraints in time, resources, and standardized practices. This study investigates the practices and challenges related to architectural documentation and communication in the development of software-intensive systems through semi-structured interviews with architects from four partner companies. The findings reveal key challenges, including identifying stakeholders for communication, inconsistent architectural definitions across teams, and knowledge transfer issues due to differing tools and terminologies. Participants also shared their reliance on informal mechanisms and ad hoc processes to address these challenges. Insights from this study highlight the need for more structured, standardized approaches, flexible documentation methods, and improved cross-domain collaboration tools. The results provide actionable recommendations for both practitioners and researchers to enhance documentation practices, improve team alignment, and ensure the effective management of architectural changes in dynamic and large-scale software systems.

During software evolution, decisions related to components' origin or source significantly impact the quality properties of the product and development metrics such as cost, time to market, ease of maintenance, and further evolution. Thus, such decisions should ideally be supported by evidence, i.e., using previous experiences and information from different sources, even own previous experiences. A hindering factor to such reuse of previous experiences is that these decisions are highly context-dependent and it is difficult to identify when previous experiences come from sufficiently similar contexts to be useful in a current setting. Conversely, when documenting a decision (as a decision experience), it is difficult to know which context factors will be most beneficial when reusing the experience in the future. An interview study is performed to identify a list of context factors that are perceived to be most important by practitioners when using experiences to support decision-making for component sourcing, using a specific scenario with alternative sources of experiences. We observed that the further away (from a company or an interviewee) the experience evidence is, as is the case for online experiences, the more context factors are perceived as important by practitioners to make use of the experience. Furthermore, we discuss and identify further research to make this type of decision-making more evidence-based. With this interview study, which focuses on which context factors are perceived as important by practitioners when reusing previous knowledge on software component reuse, we contribute with a listing of factors perceived to be important when reusing experiences from other prior decision-making cases of selecting among software components options. image

This study explores how a core ontology for missions and capabilities in systems of systems supports basic and fundamental decisions related to development and operations of systems of systems. The study is based on a previously developed core ontology for mission and capability in the context of systems of systems. From the relationships in the core ontology concepts, this study extracts fundamental design and operational decisions. These decisions are compiled into a preliminary guideline aimed at assessing the feasibility of systems of systems. This compilation uses Kipling's six honest serving men's reasoning to support clustering of decisions based on their intended outcome. The study identifies categories of generic constraints that affect these decisions. The overall aim is that the clustered decisions and the constraint categories should trigger different points of views for designers and operators as they envision their systems of systems and constituent systems. The preliminary guideline developed is then used to illustrate a road paving system, and different ways of using the guideline are discussed. The tool demonstrates flexibility, therefore setting a good starting point for brainstorming and exploration of systems of systems design and operations.