| 1. |
- Weyns, Danny, et al.
(författare)
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A Research Agenda for Smarter Cyber-Physical Systems
- 2021
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Ingår i: Journal of Integrated Design & Process Science. - Amsterdam, Netherlands : IOS Press BV. - 1092-0617 .- 1875-8959. ; 25:2, s. 27-47
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Tidskriftsartikel (refereegranskat)abstract
- With the advancing digitisation of society and industry we observe a progressing blending of computational, physical, and social processes. The trustworthiness and sustainability of these systems will be vital for our society. However, engineering modern computing systems is complex as they have to: i) operate in uncertain and continuously changing environments, ii) deal with huge amounts of data, and iii) require seamless interaction with human operators. To that end, we argue that both systems and the way we engineer them must become smarter. With smarter we mean that systems and engineering processes adapt and evolve themselves through a perpetual process that continuously improves their capabilities and utility to deal with the uncertainties and amounts of data they face. We highlight key engineering areas: cyber-physical systems, self-adaptation, data-driven technologies, and visual analytics, and outline key challenges in each of them. From this, we propose a research agenda for the years to come.
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| 2. |
- Mahdavi-Hezavehi, Sara, et al.
(författare)
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Uncertainty in Self-adaptive Systems : A Research Community Perspective
- 2020
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Ingår i: ACM Transactions on Autonomous and Adaptive Systems. - : ACM Press. - 1556-4665 .- 1556-4703. ; 15:4, s. 1-36
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Tidskriftsartikel (refereegranskat)abstract
- One of the primary drivers for self-adaptation is ensuring that systems achieve their goals regardless of the uncertainties they face during operation. Nevertheless, the concept of uncertainty in self-adaptive systems is still insufficiently understood. Several taxonomies of uncertainty have been proposed, and a substantial body of work exists on methods to tame uncertainty. Yet, these taxonomies and methods do not fully convey the research community’s perception on what constitutes uncertainty in self-adaptive systems and on the key characteristics of the approaches needed to tackle uncertainty. To understand this perception and learn from it, we conducted a survey comprising two complementary stages in which we collected the views of 54 and 51 participants, respectively. In the first stage, we focused on current research and development, exploring how the concept of uncertainty is understood in the community and how uncertainty is currently handled in the engineering of self-adaptive systems. In the second stage, we focused on directions for future research to identify potential approaches to dealing with unanticipated changes and other open challenges in handling uncertainty in self-adaptive systems. The key findings of the first stage are: (a) an overview of uncertainty sources considered in self-adaptive systems, (b) an overview of existing methods used to tackle uncertainty in concrete applications, (c) insights into the impact of uncertainty on non-functional requirements, (d) insights into different opinions in the perception of uncertainty within the community and the need for standardised uncertainty-handling processes to facilitate uncertainty management in self-adaptive systems. The key findings of the second stage are: (a) the insight that over 70% of the participants believe that self-adaptive systems can be engineered to cope with unanticipated change, (b) a set of potential approaches for dealing with unanticipated change, (c) a set of open challenges in mitigating uncertainty in self-adaptive systems, in particular in those with safety-critical requirements. From these findings, we outline an initial reference process to manage uncertainty in self-adaptive systems. We anticipate that the insights on uncertainty obtained from the community and our proposed reference process will inspire valuable future research on self-adaptive systems.
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| 3. |
- Diniz Caldas, Ricardo, 1994, et al.
(författare)
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Towards Mapping Control Theory and Software Engineering Properties using Specification Patterns
- 2021
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Ingår i: 2021 IEEE International Conference on Autonomic Computing and Self-Organizing Systems Companion (ACSOS-C). - Washington DC, United States : IEEE. - 9781665443937
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Konferensbidrag (refereegranskat)abstract
- A traditional approach to realize self-adaptation in software engineering (SE) is by means of feedback loops. The goals of the system can be specified as formal properties that are verified against models of the system. On the other hand, control theory (CT) provides a well-established foundation for designing feedback loop systems and providing guarantees for essential properties, such as stability, settling time, and steady state error. Currently, it is an open question whether and how traditional SE approaches to self-adaptation consider properties from CT. Answering this question is challenging given the principle differences in representing properties in both fields. In this paper, we take a first step to answer this question. We follow a bottom up approach where we specify a control design (in Simulink) for a case inspired by Scuderia Ferrari (F1) and provide evidence for stability and safety. The design is then transferred into code (in C) that is further optimized. Next, we define properties that enable verifying whether the control properties still hold at code level. Then, we consolidate the solution by mapping the properties in both worlds using specification patterns as common language and we verify the correctness of this mapping. The mapping offers a reusable artifact to solve similar problems. Finally, we outline opportunities for future work, particularly to refine and extend the mapping and investigate how it can improve the engineering of self-adaptive systems for both SE and CT engineers.
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| 4. |
- Ciccozzi, Federico, 1983-, et al.
(författare)
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Blended modelling - What, why and how
- 2019
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Ingår i: Proceedings - 2019 ACM/IEEE 22nd International Conference on Model Driven Engineering Languages and Systems Companion, MODELS-C 2019. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728151250 ; , s. 425-430
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Konferensbidrag (refereegranskat)abstract
- Empirical studies indicate that user experience can significantly be improved in model-driven engineering. Blended modelling aims at mitigating this by enabling users to interact with a single model through different notations. Blended modelling contributes to various modelling qualities, including comprehensibility, analysability, and acceptability. In this paper, we define the notion of blended modelling and propose a set of dimensions that characterise blended modelling. The dimensions are grouped in two classes: user-oriented dimensions and realisation-oriented dimensions. Each dimension describes a facet that is relevant to blended modelling together with its domain (i.e., the range of values for that dimension). The dimensions offer a basic vocabulary to support tool developers with making well-informed design decisions as well as users to select appropriate tools and configure them according to the needs at hand. We illustrate how the dimensions apply to different cases relying on our experience with blended modelling. We discuss the impact of blended modelling on usability and user experience and sketch metrics to measure it. Finally, we outline a number of core research directions in this increasingly important modelling area.
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| 5. |
- Shevtsov, Stepan, et al.
(författare)
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SimCA* : A Control-theoretic Approach to Handle Uncertainty in Self-adaptive Systems with Guarantees
- 2019
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Ingår i: ACM Transactions on Autonomous and Adaptive Systems. - : ACM Publications. - 1556-4665 .- 1556-4703. ; 13:4, s. 1-34
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Tidskriftsartikel (refereegranskat)abstract
- Self-adaptation provides a principled way to deal with software systems' uncertainty during operation. Examples of such uncertainties are disturbances in the environment, variations in sensor readings, and changes in user requirements. As more systems with strict goals require self-adaptation, the need for formal guarantees in self-adaptive systems is becoming a high-priority concern. Designing self-adaptive software using principles from control theory has been identified as one of the approaches to provide guarantees. In general, self-adaptation covers a wide range of approaches to maintain system requirements under uncertainty, ranging from dynamic adaptation of system parameters to runtime architectural reconfiguration. Existing control-theoretic approaches have mainly focused on handling requirements in the form of setpoint values or as quantities to be optimized. Furthermore, existing research primarily focuses on handling uncertainty in the execution environment. This article presents SimCA*, which provides two contributions to the state-of-the-art in control-theoretic adaptation: (i) it supports requirements that keep a value above and below a required threshold, in addition to setpoint and optimization requirements; and (ii) it deals with uncertainty in system parameters, component interactions, system requirements, in addition to uncertainty in the environment. SimCA* provides guarantees for the three types of requirements of the system that is subject to different types of uncertainties. We evaluate SimCA* for two systems with strict requirements from different domains: an Unmanned Underwater Vehicle system used for oceanic surveillance and an Internet of Things application for monitoring a geographical area. The test results confirm that SimCA* can satisfy the three types of requirements in the presence of different types of uncertainty.
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| 6. |
- Van De Sijpe, Jelle, et al.
(författare)
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dTAS : A Decentralized Self-Adaptive Service-Based System Exemplar
- 2020
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Ingår i: Proceedings - 2020 IEEE International Conference on Autonomic Computing and Self-Organizing Systems Companion, ACSOS-C 2020. - : IEEE. - 9781728184142 ; , s. 224-225
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Konferensbidrag (refereegranskat)abstract
- Research of self-adaptive systems can benefit from different exemplars to test and compare research methods and results. Although the number of exemplars for this area is rising, the exemplars for decentralized self-adaptive systems are limited. To that end, we introduce dTAS (decentralized Tele-Assistance System), an exemplar in the domain of service-based systems that targets decentralized adaptation of entities equipped with a classic MAPE-K feedback loop. dTAS offers predefined features that enable users to specify systems and plug in MAPE components with protocols to coordinate adaptation using different coordination patterns. We illustrate the exemplar for a scenario with three entities where the planner components coordinate the adaptation to realize their adaptation goals. © 2020 IEEE.
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| 7. |
- Camara Moreno, Javier, et al.
(författare)
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Towards Bridging the Gap between Control and Self-Adaptive System Properties
- 2020
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Ingår i: SEAMS '20. - New York, NY, USA : ACM. - 9781450379625 ; , s. 78-84
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Konferensbidrag (refereegranskat)abstract
- Two of the main paradigms used to build adaptive software employ different types of properties to capture relevant aspects of the system’s run-time behavior. On the one hand, control systems consider properties that concern static aspects like stability, as well as dynamic properties that capture the transient evolution of variables such as settling time. On the other hand, self-adaptive systems consider mostly non-functional properties that capture concerns such as performance, reliability, and cost. In general, it is not easy to reconcile these two types of properties or identify under which conditions they constitute a good fit to provide run-time guarantees. There is a need of identifying the key properties in the areas of control and self-adaptation, as well as of characterizing and mapping them to better understand how they relate and possibly complement each other. In this paper, we take a first step to tackle this problem by: (1) identifying a set of key properties in control theory, (2) illustrating the formalization of some of these properties employing temporal logic languages commonly used to engineer self-adaptive software systems, and (3) illustrating how to map key properties that characterize self-adaptive software systems into control properties, leveraging their formalization in temporal logics. We illustrate the different steps of the mapping on an exemplar case in the cloud computing domain and conclude with identifying open challenges in the area.
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| 8. |
- Casadei, Roberto, et al.
(författare)
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Digital Twins, Virtual Devices, and Augmentations for Self-Organising Cyber-Physical Collectives
- 2022
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Ingår i: Applied Sciences. - : MDPI. - 2076-3417. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The engineering of self-organising cyber-physical systems can benefit from a variety of "logical devices", including digital twins, virtual devices, and (augmented) collective digital twins. In particular, collective digital twins provide for a design construct towards collective computing, which can be augmented with virtual devices to improve the performance of existing self-organising applications-as shown through swarm exploration and navigation scenarios. The engineering of large-scale cyber-physical systems (CPS) increasingly relies on principles from self-organisation and collective computing, enabling these systems to cooperate and adapt in dynamic environments. CPS engineering also often leverages digital twins that provide synchronised logical counterparts of physical entities. In contrast, sensor networks rely on the different but related concept of virtual device that provides an abstraction of a group of sensors. In this work, we study how such concepts can contribute to the engineering of self-organising CPSs. To that end, we analyse the concepts and devise modelling constructs, distinguishing between identity correspondence and execution relationships. Based on this analysis, we then contribute to the novel concept of "collective digital twin" (CDT) that captures the logical counterpart of a collection of physical devices. A CDT can also be "augmented" with purely virtual devices, which may be exploited to steer the self-organisation process of the CDT and its physical counterpart. We underpin the novel concept with experiments in the context of the pulverisation framework of aggregate computing, showing how augmented CDTs provide a holistic, modular, and cyber-physically integrated system view that can foster the engineering of self-organising CPSs.
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| 9. |
- Weyns, Danny, et al.
(författare)
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Agent Environments for Multi-agent Systems : A Research Roadmap
- 2015
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Ingår i: Agent Environments for Multi-Agent Systems IV. - Cham : Springer. - 9783319238500 - 9783319238494 ; , s. 3-21
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Konferensbidrag (refereegranskat)abstract
- Ten years ago, researchers in multi-agent systems became more and more aware that agent systems consist of more than only agents. The series of workshops on Environments for Multi-Agent Systems (E4MAS 2004-2006) emerged from this awareness. One of the primary outcomes of this endeavor was a principled understanding that the agent environment should be considered as a primary design abstraction, equally important as the agents. A special issue in JAAMAS 2007 contributed a set of influential papers that define the role of agent environments, describe their engineering, and outline challenges in the field that have been the drivers for numerous follow up research efforts. The goal of this paper is to wrap up what has been achieved in the past 10 years and identify challenges for future research on agent environments. Instead of taking a broad perspective, we focus on three particularly relevant topics of modern software intensive systems: large scale, openness, and humans in the loop. For each topic, we reflect on the challenges outlined 10 years ago, present an example application that highlights the current trends, and from that outline challenges for the future. We conclude with a roadmap on how the different challenges could be tackled.
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| 10. |
- Shevtsov, Stepan, et al.
(författare)
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Handling New and Changing Requirements with Guarantees in Self-Adaptive Systems using SimCA*
- 2017
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Ingår i: Proceedings - 2017 IEEE/ACM 12th International Symposium on Software Engineering for Adaptive and Self-Managing Systems, SEAMS 2017, 3 July 2017 - 23 May 2017, Buenos Aires. - : IEEE. - 9781538615508 ; , s. 12-23
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Konferensbidrag (refereegranskat)abstract
- Self-adaptation provides a principled way to deal with change during operation. As more systems with strict goals require self-adaptation, the need for guarantees in self-adaptive systems is becoming a high-priority concern. Designing adaptive software using principles from control theory has been identified as one of the approaches to provide guarantees. However, current solutions can only handle pre-specified requirements either in the form of setpoint values (S-reqs) or values to be optimized (O-reqs). This paper presents SimCA* that makes two contributions to control-based self-adaptation: (a) it allows the user to specify a third type of requirement that keeps a value above/below a threshold (T-reqs); and (b) it can deal with requirement sets that change at runtime (i.e., requirements can be adjusted, activated, and deactivated on the fly). SimCA* offers robustness to disturbances and provides adaptation guarantees. We evaluate SimCA* for two systems with strict goals from different domains: an underwater vehicle system used for oceanic surveillance, and a tele-assistance system for health care support. The test results demonstrate that SimCA* can deal with the three types of requirements (STO-reqs) operating under various types of dynamics and the set of requirements can be changed on the fly.
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