In this paper, we report on the development of a webbased platform for Participatory Architectural Change Management in Air Tra c Management Systems (ATM) as part of the SESAR H2020 project PACAS. The platform is the result of an iterative requirements engineering process that actively involves ATM domain experts, starting from stakeholder analysis, to requirements elicitation, scenario de nition, and validation.
Most of today's software systems are part of larger complex systems, that include
not only technical components, but also humans and organizations. These larger
systems are otherwise known as socio-technical systems [
Change is inevitable, and socio-technical systems make no exception to the rule. Therefore, they are continuously evolving due to various possible changes: (i) system and subsystems changes, (ii) organizational and domain changes, (iii) normative and regulatory changes, and/or (iii) assets changes. Any of these changes may a ect the ability of the socio-technical system to satisfy its intended requirements and function well.
Dealing with change is an important activity in order to understand the implications of change, how it a ects the rest of the system, whether it introduces new requirements, and so on. In order to build a Change Management Platform, which will facilitate understanding, modeling and analyzing changes at di erent layers of abstraction, it is important to have the active participation of domain Copyright 2018 for this paper by its authors. Copying permitted for private and academic purposes. experts who can analyze the impact of change from di erent perspectives. Most importantly, this should be done in an iterative fashion in reingineering an already running system, so that new requirements dictated by a given change issue do not con ict with existing ones or cause problems on the rest of the system.
In this paper, we report on the development of a web-based platform for Participatory Architectural Change MAnagement which is triggered by a real case concerning the evolution of Air Tra c Management (ATM) Systems as part of the SESAR H2020 project PACAS 1. Given that decision-making involves the consideration of more high-level objectives, such as safety, performance, economic e ciency, etc., the change management process should involve multiple ATM domain stakeholders, one for each given objective, in order to explore a vast space of alternatives and agreeing on optimal solutions. It becomes, thus, crucial the active participation of stakeholders. Indeed, in ATM di erent experts from di erent companies across Europe collaborate to design the future European ATM which is intended to improve safety, while cutting down costs and environmental impacts. However, given the variety of experts, their di erent areas of expertise, as well as their geographical distribution, participatory change management requires user engagement and tools to support and facilitate the work of experts along their interaction. To address the rst concern, in recent years, gami cation is broadly used as a tool to engage participation with the help of game elements, such as leader-boards or challenges between users. On the other hand, a multi-perspective, model-based approach provides important bene ts in that: (i) it allows analyzing individual perspectives without the need of a holistic representation; (ii) it handles complexity through automated reasoning techniques in a transparent way to nd optimal solutions as a trade-o among di erent objectives.
Therefore, the platform we present is a gami ed one, and relies on the work of experts that capture the implications of change with the help of a multi-view modelling environment, which supports four default languages to allows the analysis of these four perspectives: safety, security, economic and organizational. The collaboration of experts and decision-making, on the other hand, are supported by automated reasoning techniques within each model and across models with the help of natural language processing.
The paper is structured as follows. We brie y describe the PACAS project in Section 2, while in Section 3 we describe the change management process, while Section 4 presents the platform. Section 5 discusses related work and concludes.
Air Tra c Management (ATM) systems are complex systems of systems. Participatory Architectural Change MAnagement in ATM Systems (PACAS) is a Horizon 2020 project in the framework of the SESAR Research and Innovation Action (RIA). The main objective is to better understand, model and analyze
changes at di erent layers of the Air Tra c Management (ATM) system to support change management, while capturing how architectural and design choices in uence the overall system. Understanding all possible consequences of a design decision in an ATM system is a challenge due to the complexity of ATM systems and the existence of tight interdependencies within the ATM architecture. Knowing the implications of change(s) over the whole system is crucial to support decision-making, while making sure that the ATM system does not su er from any issues with respect to functionality, safety, security, performance, cost e ciency, or other desired characteristics of a well-functioning ATM system. The project aims at developing an innovative participatory change management process wherein heterogeneous stakeholders actively participate in the architectural evolution of the ATM system.
We provide an overview of the participatory change management process, emphasizing the importance of active stakeholder participation. We describe the two main support tools, i.e. gami cation for stakeholder engagement, and automated reasoning techniques for handling complexity.
During the demo, we will introduce the PACAS approach, expressly created for architectural change management in ATM systems, and we brie y describe an ATM example case study dealing with the Sectorless change issue, and conclude with a demo of the framework.
In dealing with change, we use the following terminology: { Change Issue: refers to a planned change under evaluation. For instance, Sectorless is an ongoing change in ATM that considers moving to a sectorless approach ATM is a novel way to tackle air tra c management in upper airspace without conventional sectors that has already been proved feasible. This change is expected to improve performance and organizational aspects, with signi cant increase in capacity and controller e ciency, although safety and security issues require more investigation. { Decision point - we analyze a given change issue splitting it into several decision points. For instance, in Sectorless there are several questions one needs to answer, such as How many aircrafts should be assigned to each air tra c controller (ATC)?, or What criteria should be used to assign an aircraft to a controller?, and so on. The rst question is captured by the decision point Number of ights per ATC as opposed to the existing Handover of aircrafts. { Solution - within each decision point, we analyze di erent options, aka solutions. In Sectorless, automatic assignment is envisioned. { View - each solution is analyzed from a given expert perspective, aka view.
In PACAS we support these four views: safety, organizational, security and
economic.
{ Contribution - in order to assess how well a given solution fares with respect
to already set objectives, we capture how a solution contributes to overall
validation targets laid down by Eurocontrol and SESAR. Example validation
targets include Increased safety and Triple capacity.
{ Model - For each view, we support default modeling notations to allow
experts to represent but also analyze a given solution from their perspective,
alongside the possibility to upload les should di erent languages or
notations be used by the experts. The default languages in PACAS are: Fault
Tree [
The change management of complex systems, such as ATM systems, cannot be handled by a single person. For each change issue, i.e., for each planned change to be done in an ATM system from the implementation of a single component in the cocKPIt to a new way of managing tra c in the airspace, teams of experts need to collaborate in order to specify the best modi cations of the system.
As such, we support the interaction of these main types of users, namely experts, team leaders, builders, company representatives and a game master.
The Game Master has the power to start a change issue, i.e., ask di erent companies to study how to apply the change and propose the best modi cations (solutions). The Company Representatives serve as contact points in the various companies involved in the analysis of a change issue. Thus, they deal with the creation of teams. In PACAS teams are created per area of expertise (view).
Team Leaders will choose the best modi cation(s) of the ATM system for a change issue. They will study the diagrams/models developed or adopted by the Experts, who represent domain experts that know at least one of the modeling languages used to specify and analyze changes and their implications. Team leaders interact with experts, and decide which solution provided by Builders (see below) is the best for the change issue. Similarly to Experts, they are experienced in at least one of the perspectives supported by the PACAS web platform, and have a good knowledge on the part of the ATM system involved in the change issue. Thus, a Team Leader could be an expert too. Finally, Builders are not only domain experts, but have also a wide knowledge of the overall system. They specify the solutions that are to be analyzed by Team Leaders and Experts.
They all interact following the process in Fig. 1 to make a decision.
The novelty of the PACAS platform (Fig. 2) relies on these three main pillars:
Gami cation . In order to drive collaboration and keep users engaged,
PACAS makes use of psychological and social drivers for interaction [
Multi-view modeling . Integration of the re ned modeling notations and an automatically generated shared model for decision-making, in which contribution links from solutions to validation targets are drawn taking into account the result of the automated reasoning on multi-criteria decision analysis. The platform is modular, in the sense that new modeling environments can be integrated to support experts using di erent languages in representing and further analysing aspects related to their area of expertise.
Automated reasoning techniques . PACAS supports local reasoning
techniques for the security view, namely well-formedness, security and threat analysis
for STS-ml [
In this paper we have reported on a gami ed collaborative platform for participatory change management in ATM system. The resulting platform is the result of the end-to-end inclusion of ATM domain stakeholders, who have actively participated starting from early requirements the nal release of the platform, through a number of iterations where we have presented mockups and performed prototype validations.
As far as our knowledge goes, there is little work that reports on such gami ed
platform, the creation of which involves stakeholders active participation.
REne (Snijders et al. [
In developing the PACAS platform we have faced several challenges, such as the need for vast amount of domain speci c knowledge to tailor a customized platform for the ATM domain, identifying the right domain stakeholders, terminology alignment, and last but not least characterizing stakeholders for the gami cation solution starting from a small representative set.
Future work considers the application of the PACAS platform in other domains and scenarios requiring collaborative decision-making among di erent stakeholders, studying the impact of new solutions on the strategic layer considered by PACAS, considering not only economic, organizational, security, and safety aspects, but also integrating new ones. Potential domains include healthcare where privacy issues need to be dealt with and supported by already running systems, especially after the latest General Data Privacy Regulation 2. Acknowledgments. This project has received funding from the SESAR Joint Undertaking under grant agreement No 699306 under European Union's Horizon 2020 research and innovation programme.