In the field of systems-of-systems (SoS) engineering, there is broad agreement on a few characterizations, and these are currently being standardized. However, many aspects in the field still lack an established terminology. In particular, there are unclarities related to the internal structure of an SoS, and on the internal states of constituent systems. In this paper, a refined terminology is therefore proposed, which covers the internal substructure of an SoS; the states of constituent systems in relation to those substructures; and how it relates to hierarchical levels. This terminology can also be used to classify the characteristics of an SoS through different metrics. The terminology is illustrated through three examples of SoS applications in various domains. © 2019 IEEE.

The research area systems-of-systems engineering has increased rapidly over the last decade and now contains a substantial body of literature. To get an overview of the field, a systematic mapping of the literature has been done, covering over 3000 papers. It revealed a field massively dominated by US researchers, with an emphasis on military and space systems. A large number of people are involved, but few researchers focus on the area, and citations are fairly low compared to other fields. Important research topics include architecture, modeling and simulation, integration and interoperability, communication, sustainability, and safety and security. There are signs of immaturity within the research area, and it is recommended that existing venues are complemented with an international scientific event with very high standards for submissions.

Systems-of-systems are characterized by the independence of their constituent elements. Such an element is usually socio-technical, comprising technology, humans, or organizations. To capture its independence, it needs to be viewed as an intelligent agent that relies on an internal model of the world for its decision-making. Hence, a system-of-systems model will include multiple agents that inside themselves contain different models of the same system-of-systems. Describing these overlapping subjective models and their usage by the agents is essential to properly understand the resulting behavior of the overall system-of-systems. Current modeling practices are not well suited for dealing with this, and the paper therefore outlines an ontology that makes the agents and their internal models more explicit. The paper also discusses the implications such models have on systems engineering practices and how they address known system-of-systems engineering pain points.

As systems-of-systems start to be more common in commercial applications, an analysis of emergent properties related to utility and cost for all stakeholders becomes critical. This paper describes an approach for this based on network simulation and game theory, which is applied to truck highway platooning. The emergent properties of energy efficiency and transport efficiency are studied as a consequence of the strategies for platoon formation, and it is shown that having information about the route planning of other vehicles has a significant positive effect on the properties. This indicates the need for a mediator in the platooning system-of-systems architecture. Its role is to communicate plans of the constituent systems.

Cyber-physical systems is an extension of traditional embedded systems, where communication to the outside world is given more emphasis. This leads to a new design space also for software development, allowing new allocation strategies for functionality. In traditional embedded systems, all functionality was inside the product, but now it becomes possible to partition the software between the embedded systems and IT systems outside the product. This paper investigates, through a case study from the automotive domain, possible new allocation alternatives where computation is offloaded from the embedded system to a server, and what additional architectural concerns this leads to, including performance, resource utilization, robustness, and lifecycle aspects. In addition, the paper addresses new opportunities created by allocating functionality outside the embedded systems, and thus making data available for extended services, as well as the larger concerns that result on the organizational level, including new competency in architecture and DevOps.

Platooning of trucks on motorways has been proposed as a method of reducing fuel consumption. It requires communication between the trucks to control the distance between them. However, this system-of-systems (SoS) cannot only contain the trucks, but also needs to include mediating off-board services for match-making to find suitable constellations of trucks, and for creating platooning incentives by distributing the profit made equally among the constituent systems. This paper analyzes what actors in the SoS would be suitable to operate these services, and also business models that cover the cost for their implementation and operation. It concludes that the truck OEMs have a vital role in creating the mediating services, and that a suitable business model would be based on usage fees for the services rather than upfront payment for platooning equipment. 

Many industries rely heavily on embedded software and systems to maximize business value in their products. These systems are very complex and the architecture is important to control the complexity and make development efficient. There are often also connections between the embedded system and the different lifecycle processes, and hence to the enterprise systems supporting those processes. It is rare to start from scratch when developing new products, and instead these companies evolve their products over time, which means that architecting needs to be evolutionary. In this chapter, it is described what such an evolutionary architecting process can look like based on observations from industry, and how the process can be continuously improved using a maturity model. It is also presented how the embedded system relates to different elements of the enterprise architecture.

Most industrial software-intensive systems have a very long life span, and undergo many changes after their initial conception. To ensure that they maintain the desired system-level properties, it is essential that their architecture is also updated to reflect the added functionality. To this end, we have investigated how Evolutionary Architecting should be carried out in order to provide a strong basis for a system, not only at conception but throughout its life. The results are concrete and based on empirical findings, and include both a new state-of-the-art process description and a light-weight maturity evaluation method.

This paper addresses the problem of exchanging complex data between the constituent systems in a system-of-systems. This is necessary to ensure that they have compatible understandings of the world surrounding them and entails a need for semantic interoperability between the constituents. Through a case study of a road construction system-of-systems, the world wide web technologies of linked data and ontologies are explored as a framework for data representation and exchange. This data includes several broad categories, such as assets, interfaces, organizations, capabilities, missions, and observations, as well as various properties of those. It is also discussed how the constituents can use this data for reasoning and decision making. The results have been validated through a simulation-based research prototype of the road construction case, from which experiences are reported. 

This paper addresses the problem of exchangingcomplex data between the constituent systems in a system-ofsystems. This is necessary to ensure that they have compatibleunderstandings of the world surrounding them and entails aneed for semantic interoperability between the constituents.Through a case study of a road construction system-of-systems,the world wide web technologies of linked data and ontologiesare explored as a framework for data representation andexchange. This data includes several broad categories, such asassets, interfaces, organizations, capabilities, missions, andobservations, as well as various properties of those. It is alsodiscussed how the constituents can use this data for reasoningand decision making. The results have been validated through asimulation-based research prototype of the road constructioncase, from which experiences are reported.

Systems-of-systems (SoS) are becoming increasingly common in more and more domains, spreading from the initial focus on government-controlled areas such as defense to open market industries. This implies that collaborative SoS are becoming more important, where the constituents need to be given incentives to join and remain within the SoS. Game theory has been proposed as a framework to model and analyze such SoS mechanisms. It aims at providing incentives to the independently operated and managed constituents. This paper presents a systematic literature review on the applications of game theory to SoS engineering, together with a synthesis aiming at capturing the best practices for doing such an analysis. The main conclusions are that game theory can be applied to SoS in a wide range of application areas, and deal with problems related to acquisition, design, and operations. In particular, the operational formation of SoS are well suited for this kind of analysis, and it often requires the use of simulation techniques. However, most results in the field lack a validation in practice.

Many industries developing complex products based on embedded systems rely on architecting as a key activity. Furthermore, they use product line approaches to find synergies between their products. This means that they use a base platform which is adapted to different products, and the architecture of the product line thus evolves over time. In previous case studies we have seen that these companies often lack a defined process for the evolutionary architecting of these product lines. The contribution of this paper is to present such a process, which matches key characteristics of mature architecting practices. It is also discussed how this process compares to observations in industry.

This paper discusses the topic of uncertainty in the context of architecting embedded software and systems. It presents links between complexity and uncertainty, and identifies different kinds of uncertainty. Based on this, it elaborates why uncertainty arises in the architecting of software-intensive systems, and presents ten different tactics that can be employed to deal with uncertainty and mitigate the associated risks.

The rapid digitization of society is to a large extent driven by the interconnection of existing systems in order to co-ordinate their activities. This leads to systems-of-systems (SoS), where the parts more or less voluntarily co-operate for mutual benefits while keeping their autonomy. The term SoS started to become relevant some 20 years ago, and accelerated as a research area about 10 years ago. Although some people tend to take SoS as a synonym for large and complex systems, the research community has arrived at a fairly precise characterization of the term. In an SoS, the elements, or constituent systems, exhibit an operational and managerial independence, meaning that they can operate outside the SoS context, and have different owners. They choose to collaborate in order to achieve a common goal, manifested as an emergent property of the SoS, i.e. a property not existent in any of its parts in isolation. The field so far has been dominated by US researchers focusing on military and space applications. Key topics include architecture, communications, interoperability, modeling and simulation, and also a number of properties where dependability attributes such as safety play an important role. From its origins in the government driven sectors, SoS are now spreading to civilian and commercial usage. To investigate the needs and strategies for Sweden in relation to SoS, VINNOVA in late 2014 commissioned a consortium led by the Swedish Institute of Computer Science (SICS) to develop a research and innovation agenda for the area. The agenda project has included an industrial perspective captured in a series of workshops with practitioners, and also a research perspective. The latter was handled through an extensive research literature review, which indicated a poor representation of Scandinavia in the SoS research community. Also, a survey was sent to all relevant Swedish universities, research institutes, and funding agencies, and the result of this was somewhat contradictory. Many researchers are indeed working on topics related to SoS, but often use different terms for it, and publish at other venues than the SoS community. Given the large, but scattered, activity in the highly multidisciplinary SoS area, SICS and the Swedish Chapter of the International Council on Systems Engineering (INCOSE) decided to organize the 1st Scandinavian Workshop on the Engineering of Systems of Systems (SWESoS 2015). The primary purpose of the workshop was to create a meeting place for researchers and practitioners interested in SoS. The workshop was intended to be an informal event, focusing on presentation of results and ongoing research, to stimulate interaction among the researchers. This proceedings volume contains the extended abstracts of those presentations. In many cases, the presentations are based on work already published elsewhere, and the interested reader can find links to more material in each contribution. The scope of the workshop was all aspects related to SoS engineering. This included, but was not restricted to, the following topics when applied to systems of systems: Autonomous and cooperative systems; Business models, including software ecosystems; Case studies of applications in different domains; Control strategies; Communication; Dependability, robustness, and other quality attributes; Enterprise architecture; Governance; Interoperability; Modeling and simulation, including multi-agent systems; Service oriented architecture; Systems engineering methods; and Systems thinking. In total, 16 papers were submitted to the workshop, and 13 were accepted for presentation, whereas the remaining three were somewhat outside the core scope of the event.

Vehicle platooning has been studied for several decades, with objectives such as improved traffic throughput on existing infrastructure or reduced energy consumption. All the time, it has been apparent that safety is an important issue. However, there are no comprehensive analyses of what is needed to achieve safety in platooning, but only scattered pieces of information. This paper investigates, through a systematic literature review, what is known about safety for platooning, including what analysis methods have been used, what hazards and failures have been identified, and solution elements that have been proposed to improve safety. Based on this, a gap analysis is performed to identify outstanding questions that need to be addressed in future research. These include dealing with a business ecosystem of actors that cooperate and compete around platooning, refining safety analysis methods to make them suitable for systems-of-systems, dealing with variability in vehicles, and finding solutions to various human factors issues.

Design patterns are an established approach for reusing knowledge about good solutions to recurring problems. Patterns can be seen as a way of describing the best practices, and have been used in many different fields, ranging from building architecture and city planning to software development. There are also scattered results relating to patterns for systems-of-systems. The purpose of this paper is to summarize and review the literature on patterns for systems-of-systems and make a synthesis of a recommended approach for the field. Specifically, the novel contributions of the paper are to propose a consolidated structure for describing individual patterns and suggest the dimensions along which a pattern catalog can be organized. The paper also summarizes the concrete patterns suggested in the existing literature and classifies them according to the recommended structure. 

This report constitutes a strategic research and innovation agenda for the area systems-of-systems. The agenda has been developed during the first half of 2015 in a project led by SICS Swedish ICT AB, in collaboration with INCOSE Sweden and a large number of representatives from industry and academia, with financial support from Vinnova. The overall conclusion of the agenda is: Sweden needs a world-leading capability to rapidly develop trustworthy systems-of-systems. A system-of-systems (SoS) can informally be defined as a group of independent collaborating systems. The elements of an SoS, called constituent systems, retain an operational and managerial independence, but when combined in a certain way, they provide together a new capability that is emergent from their cooperation. There are many applications of SoS, often as a consequence of the digitization of society which opens new possibilities for system integration. Examples can be found within command and control systems for defense and civilian crisis management; construction and mining; manufacturing and the reindustrialization; transportation; and health care. System integration is traditionally a Swedish area of strength, and by improving SoS knowledge, competitive advantages can be reached. SoS is also an important enabler for innovation, through the ability to combine existing technical products, processes, and organizations in new ways. Having the ability for rapid SoS development is very important for businesses to bring new innovations to market. However, to advance the practice of SoS engineering, a number of challenges need to be addressed, including improving the theoretical foundations; the socio-technical aspects; architecture; modeling and simulation; interoperability; trust; business and legal aspects; development processes and methods; and standardization. As part of the agenda project, a survey has been done of international and Swedish research in the area. Internationally, the SoS field is dominated by US researchers, with a very strong focus on military and space applications. A large number of people are involved, but few persons focus on the area. In comparison, Sweden has entered the research area much later, and only now is attention growing. As is the case internationally, few researchers focus on SoS, and many of them do not even call their research SoS. Activities are scattered over many organizations throughout the country. Many of the researchers in SoS in Sweden come from a background in Software Engineering or Control Engineering, and this is in contrast with the international research, which has its basis in Systems Engineering. In Sweden, research topics such as business aspects (in particular innovation), control systems, governance, and Internet of Things are more pronounced than internationally. However, there is little research in Sweden on the underlying, fundamental principles of SoS engineering. This is likely to be in part a consequence of the funding strategies currently implemented. The analysis shows a broad but scattered Swedish research community lacking critical mass. There is a high competence in software and control engineering, and in empirical research methods, but the lack of systems engineering competence is alarming, since it is fundamental for desired advances, such as in the reindustrialization (Industry 4.0). To achieve the desired capability in SoS development requires knowledge, competence, and capacity, which are provided through substantially increased research and education actions. It is suggested that research in the area is organized as a national SoS center-of-centers that coordinates activities at different academic member organizations. This requires increased research funding. There is also an urgent need for education in systems engineering, systems thinking, and SoS. It is proposed that the center-of-centers also takes responsibility for this, by developing joint courses in those disciplines, including on-line courses for practitioners, and PhD schools for industrial and academic doctoral students. To complement this, societal actions are needed to remove obstacles for building SoS, and enforcing standards. Finally, it is necessary to create meeting places, including triple helix flagship projects, that can fuel the interactions between individuals and organizations interested in SoS.

The concept of emergence refers to phenomena that occur on a system level without being present at the level of elements in the system. Since a system is created to achieve certain emergent system-level behavior, while avoiding other emergent properties, a deeper understanding of emergence is crucial to further the field of systems engineering. It has also been identified as one of the key aspects of systems-of-systems. However, the concept has been the topic of much debate in philosophy, systems science, and complexity science for a long time, and there is yet no precise characterization on which there is general agreement. In this paper, a selection of the literature on emergence is reviewed to identify some key characteristics and disputes. The various philosophical points of view are analyzed from the perspective of systems engineering, to sort out what characteristics have practical implications, and which philosophical quiddities are merely of theoretical interest. The paper also relates emergence to systems engineering practices and suggests some tactics for dealing with emergence. Key results are that the inclusion of an explicit observer is essential for understanding and handling emergence, and that emergence is closely related to the amount of information required to describe the system which is also a defining characteristic of complexity.

In this report we describe results from the work on business case analysis of the Sweden for Platooning (S4P) project. Platooning has the potential to contribute to the on-going transformation of the transport sector by reducing environmental impact, saving fuel, as well as (to a lesser extent) by improving traffic flow and safety and in the long run reducing driver hours. In order to fulfil these promises, it must be shown that there are viable business cases for all involved actors. This report describes the analysis of truck platooning business cases performed in the S4P project.

Some of the main findings are that there is a significant potential for reducing fuel consumption and hence CO2 exhaust through platooning; that waiting on the order of minutes for a platooning opportunity is reasonable but that taking another route is probably not; that it is necessary to have mediating services that help platoons to form and share the costs and benefits associated with platooning; and that there are different possible ways of implementing a system for sharing the benefits.

This article describes the architecture life cycle effect analysis (ALCEA) method, a structured method for evaluating proposed new architectures for software-intensive systems. The method evaluates a proposed architecture by quantifying its effect on the performance of system life-cycle phases. The method is instantiated by identifying the relevant life-cycle phases of the system under investigation and a set of evaluation functions that capture, in terms of basic factors, the effect of different architectural decisions on key life-cycle PAs, such as revenue, operating resources, and investments. The method results in a transparent cost and revenue structure, documented in a tabular form, based on quantifiable factors from the developing organization. The results of the method can be used directly as part of a business case, and their robustness can be estimated by sensitivity analysis. The ALCEA method is designed for system-level architectural analysis, covering both software and hardware aspects. In this article, we introduce the ALCEA method and provide a detailed example of how to apply it in the evolution of embedded systems. Moreover, we share early experiences of using the method in large-scale industrial settings.

In a system-of-systems, independent constituent systems collaborate to achieve broader capabilities they cannot provide on their own. This paper investigates the nature of the constituent system capabilities beyond basic operational actions, to achieve a deeper understanding of what is required to participate in a system-of-systems. Through a case study of industrial ecosystems, the need is shown for planning how to use basic operational capabilities, for dynamic capabilities to achieve long-term evolution, and for resilience capabilities to deal with perturbations. This also affects the governance of the system. The findings are used to extend an existing conceptual model of constituent systems and to characterize collaboration in a system-of-systems that implements a value network. 

The development of system-of-systems (SoS) requires a continuous interplay between design decisions on the SoS level and those on the level of its constituent systems (CS), which often preexist and need to be adapted as the SoS evolves. This involves not only preparing the CS to participate in a particular SoS, but also designing the CS architecture to make it easily adaptable to a future SoS context. The problem is in part addressed in an emerging SoS framework in the manufacturing domain called Industry 4.0. It focuses on connected and digitalized production with the ambition of increasing flexibility and efficiency. This paper investigates how Industry 4.0 standards can be used in an SoS context to make CS more flexible and adaptive, and evaluates their usefulness outside manufacturing. The study is based on a case from the construction domain, for which a generic SoS architecture is developed. Several extensions and adaptations of Industry 4.0 are suggested, including specifications of ontologies for missions and workflows. © 2019 The Authors. 

Road construction is a very large business segment, consuming enormous public funding every year and with significant environmental impacts. However, the rate of efficiency improvement during the last few decades has been negligible, whereas other industries, such as manufacturing, have seen very large improvements by applying automation and Leanbased flow optimization across the production system. In this paper, we outline a system-of-systems concept for road construction which applies similar principles as have previously proved successful in other industries. The paper identifies efficiency attributes and wastes in current practices, which lead to a conceptual solution that focuses on improved coordination of working machines. Technical elements from Industry 4.0 are considered as potential building blocks in this concept, identifying similarities and differences between the construction domain and other industries. Finally, challenges are identified, in particular within knowledge representation and information management.

Federated embedded systems (FES) is an approach for systems-of-systems engineering in the domain of cyber-physical systems. It is based on the idea to allow dynamic addition of plug-in software in the embedded system of a product, and through communication between the plug-ins in different products, it becomes possible to build services on the level of a federation of products. In this paper, architectural concerns for FES are elicited, and are used as rationale for a number of decisions in the architecture of products that are enabled for FES, as well as in the application architecture of a federation. A concrete implementation of a FES from the automotive domain is also described, as a validation of the architectural concepts presented.

The automotive industry has recently developed the embedded software standard AUTOSAR, which is now being introduced widely in production vehicles. The standard structures the application into reusable components that can be deployed in a specific vehicle using a configuration scheme. However, this configuration takes place at design time, with no provision for dynamically installing components to reconfigure the system. In this paper, we present the conceptual design of a dynamic component model that extends an AUTOSAR based control unit with the possibility to add plug-in components that execute on a virtual machine. This concept is intended to give benefits in terms of much shorter deployment time for new functions, even into vehicles that have already been produced. Further, it creates opportunities for vehicles to take part in federated embedded systems together with other products. It also opens up a market for third-party developers, and fosters open innovation in an ecosystem around the automotive software business.

The characteristics of systems-of-systems (SoS) present fundamental challenges regarding properties such as safety, security, reliability, and robustness. This is due to the SoS nature where a collection of independent systems cooperate to fulfil certain high-level objectives. Risk analysis is thus an important activity in SoS engineering. This paper presents a risk analysis method which extends the existing STAMP safety analysis method that is based on systems thinking. Our extensions are aimed at coping with other risks than safety, and the usage is tailored to SoS. The method aims at deriving requirements on the constituent systems that will reduce the emergent risks on the SoS as a whole. The method has been applied to a case study of vehicle platooning.

Due to the increasing importance of cyber-physical and embedded systems in industry, there is a strong demand for engineers with an updated knowledge on contemporary technology and methods in the area. This is a challenge for educators, in particular when it comes to creating hands-on experiences of real systems, due to their complexity and the fact that they are usually proprietary. Therefore, a laboratory environment that is representative of the industrial solutions is needed, with a focus on software and systems engineering issues. This paper describes such an environment, called the Mobile Open Platform for Experimental Design (MOPED). It consists of a model car chassis, equipped with a network of three control units based on standard hardware, and running the automotive software standard AUTOSAR, which consists of operating system, middleware, and application software structures. It is equipped with various sensors and actuators, and is open to extensions both in hardware and software. It also contains elements of future systems, since it allows connectivity to cloud services, development of federated embedded systems, and continuous deployment of new functionality. In this way, the platform provides a very relevant learning environment for cyber-physical systems, today and in the future.

Urbanization is one of the major current trends in society. Cities around the world are looking into 'smart' solutions based on information and communication technology to deal with the challenges that result from this development. Mobility is one of the most important areas to address, and system-of-systems solutions where vehicles and infrastructure are connected have a potential to improve urban transportation in many aspects. In this paper, current initiatives related to mobility in smart cities around the world are surveyed, and this is complemented with input from focus groups of transportation stakeholders to identify the important aspects of the problem. Based on this, challenges related to the application of systems-ofsystems in urban mobility are identified.

Context: Traditionally, Embedded Systems (ES) are tightly linked to physical products, and closed both for communication to the surrounding world and to additions or modifications by third parties. New technical solutions are however emerging that allow addition of plug-in software, as well as external communication for both software installation and data exchange. These mechanisms in combination will allow for the construction of Federated Embedded Systems (FES). Expected benefits include the possibility of third-party actors developing add-on functionality; a shorter time to market for new functions; and the ability to upgrade existing products in the field. This will however require not only new technical solutions, but also a transformation of the software ecosystems for ES. Objective: This paper aims at providing an initial characterization of the mechanisms that need to be present to make a FES ecosystem successful. This includes identification of the actors, the possible business models, the effects on product development processes, methods and tools, as well as on the product architecture. Method: The research was carried out as an explorative case study based on interviews with 15 senior staff members at 9 companies related to ES that represent different roles in a future ecosystem for FES. The interview data was analyzed and the findings were mapped according to the Business Model Canvas (BMC). Results: The findings from the study describe the main characteristics of a FES ecosystem, and identify the challenges for future research and practice. Conclusions: The case study indicates that new actors exist in the FES ecosystem compared to a traditional supply chain, and that their roles and relations are redefined. The business models include new revenue streams and services, but also create the need for trade-offs between, e.g., openness and dependability in the architecture, as well as new ways of working.

Agile approaches have been highly influential to the software engineering practices in many organizations, and are increasingly being applied in larger companies, and for developing systems outside the pure software domain. To understand more about the current state of agile, its applications to safety-critical systems, and the consequences on innovation and large organizations, a seminar was organized in Stockholm in 2014. This paper gives an overview of the topics discussed at that seminar, a summary of the main results and suggestions for future work as input to a research agenda for agile development of safety-critical software.

Abstract Software ecosystems are becoming a common model for software development in which different actors cooperate around a shared platform. However, it is not clear what the implications are on software quality when moving from a traditional approach to an ecosystem, and this is becoming increasingly important as ecosystems emerge in critical domains such as embedded applications. Therefore, this paper investigates the challenges related to quality assurance in software ecosystems, and identifies what approaches have been proposed in the literature. The research method used is a systematic literature mapping, which however only resulted in a small set of six papers. The literature findings are complemented with a constructive approach where areas are identified that merit further research, resulting in a set of research topics that form a research agenda for quality assurance in software ecosystems. The agenda spans the entire system life-cycle, and focuses on challenges particular to an ecosystem setting, which are mainly the results of the interactions across organizational borders, and the dynamic system integration being controlled by the users.

Systems-of-systems are designed to provide a capability that their constituent systems cannot achieve individually. A key property is that the constituent systems have some degree of operational and managerial independence. The concepts of capability and independence are thus central to the field of systems-of-systems. Yet the contemporary literature and standards only give vague definitions of these terms. This vagueness is a barrier to progress in the field, and this paper aims at contributing with a more detailed conceptualization. It describes a system capability as a state-transforming process that uses certain resources. Independence means that the system has a choice about when and how its capabilities should be activated. This requires that the system is an intelligent agent with a notion of utility, a perception of the world around it, and a decision-making capability. When given a mission, the system can complete that mission by activating appropriate combinations of capabilities. A system-of-systems can decompose its mission into parts that correspond to the capabilities of various constituent systems.

Cybersecurity is an important concern in systems-of-systems (SoS), where the effects of cyber incidents, whether deliberate attacks or unintentional mistakes, can propagate from an individual constituent system (CS) throughout the entire SoS. Unfortunately, the security of an SoS cannot be guaranteed by separately addressing the security of each CS. Security must also be addressed at the SoS level. This paper reviews some of the most prominent cybersecurity risks within the SoS research field and combines this with the cyber and information security economics perspective. This sets the scene for a structured assessment of how various cyber risks can be addressed in different SoS architectures. More precisely, the paper discusses the effectiveness and appropriateness of five cybersecurity policy options in each of the four assessed SoS archetypes and concludes that cybersecurity risks should be addressed using both traditional design-focused and more novel policy-oriented tools. 

Context: Component-based software engineering (CBSE) is a common approach to develop and evolve contemporary software systems. When evolving a system based on components, make-or-buy decisions are frequent, i.e., whether to develop components internally or to acquire them from external sources. In CBSE, several different sourcing options are available: (1) developing software in-house, (2) outsourcing development, (3) buying commercial-off-the-shelf software, and (4) integrating open source software components. Objective: Unfortunately, there is little available research on how organizations select component sourcing options (CSO) in industry practice. In this work, we seek to contribute empirical evidence to CSO selection. Method: We conduct a cross-domain survey on CSO selection in industry, implemented as an online questionnaire. Results: Based on 188 responses, we find that most organizations consider multiple CSOs during software evolution, and that the CSO decisions in industry are dominated by expert judgment. When choosing between candidate components, functional suitability acts as an initial filter, then reliability is the most important quality. Conclusion: We stress that future solution-oriented work on decision support has to account for the dominance of expert judgment in industry. Moreover, we identify considerable variation in CSO decision processes in industry. Finally, we encourage software development organizations to reflect on their decision processes when choosing whether to make or buy components, and we recommend using our survey for a first benchmarking.

Component-based software engineering (CBSE) is a common approach to develop and evolve contemporary software systems. When evolving a system based on components, make-or-buy decisions are frequent, i.e., whether to develop components internally or to acquire them fromexternal sources. In CBSE, several different sourcing options are available: 1) developing software in-house, 2) outsourcing development, 3) buying commercial-off-the-shelf software, and 4) integrating open source software components. Unfortunately, there is little available research on howorganizations select component sourcing options (CSO) in industry practice. In this work, we seek to contribute empirical evidence to CSO selection. Method: We conduct a cross-domain survey on CSO selection in industry, implemented as an online questionnaire. Based on 188 responses, we find that most organizations consider multiple CSOs during software evolution, and that the CSO decisions in industry are dominated by expert judgment. When choosing between candidate components, functional suitability acts as an initial filter, then reliability is the most important quality. We stress that future solution-oriented work on decision support has to account for the dominance of expert judgment in industry. Moreover, we identify considerable variation in CSO decision processes in industry. Finally, we encourage software development organizations to reflect on their decision processes when choosing whether to make or buy components, and we recommend using our survey for a first benchmarking.

It has been suggested in the literature to organize software in autonomous vehicles as hierarchical layers where each layer makes its own decisions based on its own world model. This paper presents two alternative designs for autonomous construction vehicles based on the layered framework 4D/RCS. As a first step, the typical use cases for these vehicles were defined. Then one use case for a hauler was traversed through the two alternatives to see how they supported safety, flexibility and the use of a product platform. We found that the coordination between bucket control and motion control must be done at a low level in the hierarchy and that the relationship between the vehicle actuators and the built-in autonomous system is important for how the software is organized.

Autonomous and intelligent construction equipment is an emergent area of research, which shares many characteristics with on-road autonomous vehicles, but also have fundamental differences. Construction vehicles usually perform repetitive tasks in confined sites, such as quarries, and cooperate with other vehicles to complete common missions. A quarry can be viewed as a system-of-systems and the vehicles are individual systems within the site system. Therefore it is important to analyze the site system, i.e. included vehicles, surrounding systems, and system context, before the introduction of autonomous vehicles. It is necessary to map the needed infrastructure, and the needed input information from on-board sensors and off-board information suppliers, before designing the vehicle electronics system. This paper describes how we identified sensory and input signal needs for an autonomous articulated hauler in a scenario at a quarry site. Different architectural alternatives are evaluated and a set-up for a quarry site is suggested.

This report is concerned with the vision of smart interconnected objects, a vision that has attracted much attention lately. In this paper, embedded, interconnected, open, and heterogeneous control systems are in focus, formally referred to as Federated Embedded Systems. To place FES into a context, a review of some related research directions is presented. This review includes such concepts as systems of systems, cyber-physical systems, ubiquitous computing, internet of things, and multi-agent systems. Interestingly, the reviewed fields seem to overlap with each other in an increasing number of ways.

The development within the area of embedded systems (ESs) is moving rapidly, not least due to falling costs of computation and communication equipment. It is believed that increased communication opportunities will lead to the future ESs no longer being parts of isolated products, but rather parts of larger communities or federations of ESs, within which information is exchanged for the benefit of all participants. This vision is asserted by a number of interrelated research topics, such as the internet of things, cyber-physical systems, systems of systems, and multi-agent systems. In this work, the focus is primarily on ESs, with their specific real-time and safety requirements. While the vision of interconnected ESs is quite promising, it also brings great challenges to the development of future systems in an efficient, safe, and reliable way. In this work, a pre-study has been carried out in order to gain a better understanding about common concepts and challenges that naturally arise in federations of ESs. The work was organized around a series of workshops, with contributions from both academic participants and industrial partners with a strong experience in ES development. During the workshops, a portfolio of possible ES federation scenarios was collected, and a number of application examples were discussed more thoroughly on different abstraction levels, starting from screening the nature of interactions on the federation level and proceeding down to the implementation details within each ES. These discussions led to a better understanding of what can be expected in the future federated ESs. In this report, the discussed applications are summarized, together with their characteristics, challenges, and necessary solution elements, providing a ground for the future research within the area of communicating ESs.

This study presents a core ontology for missions and capabilities in systems of systems. The aim of the study is to create artifacts that facilitate precise understanding of fundamental concepts of SoS. An ontological approach proposes and develops taxonomic homogeneity and structural knowledge of SoS. The ontology development process involved workshop sessions with industry experts and meta modelling of the different concepts and their relationships. The ontology includes thirteen concepts of types physical things, people, information and mixed. These concepts are defined and their relations are briefly described. The developed ontology is further illustrated using a wildfire scenario case study.

The automotive industry has recently agreed upon the embedded software standard AUTOSAR, which structures an application into reusable components that can be deployed using a configuration scheme. However, this configuration takes place at design time, with no provision for dynamically installing components to reconfigure the system. In this paper, we present the design and implementation of a dynamic component model that extends AUTOSAR with the possibility to add plug-in components at runtime. This opens up for shorter deployment time for new functions; opportunities for vehicles to participate in federated embedded systems; and involvement of third-party software developers.

Understanding the needs and constraints of systems in general and a system-of-systems in particular can be challenging, yet crucial. Relying only on upfront activities will not be sufficient. Important information can be gathered around the performance and behavior of the system as well as stakeholder needs in operation. A digital twin is a way to model and understand the operation of a system. To understand the challenges and enablers related to digital twins in a system-of-systems context, we performed a literature study. In total, only 10 papers were identified that explicitly address this topic, all from the last five years, indicating that this is an active field of research. The papers revealed that definitions and terminology are unclear and that similar challenges as for systems-of-systems also exist for systems-of-digital twins. The complexity and dynamic nature of systems-of-systems motivate further study of digital twins to understand needs and constraints. However, key challenges such as concepts and principles of digital twins for systems-of-systems, cost and benefits, and evolution needs to be better understood.