| 1. |
- Angelopoulos, Konstantinos, et al.
(författare)
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Model predictive control for software systems with CobRA
- 2016
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Ingår i: Proceedings - 11th International Symposium on Software Engineering for Adaptive and Self-Managing Systems, SEAMS 2016. - New York, NY, USA : ACM. - 9781450341875 ; , s. 35-46
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Konferensbidrag (refereegranskat)abstract
- Self-adaptive software systems monitor their operation and adapt when their requirements fail due to unexpected phenomena in their environment. This paper examines the case where the environment changes dynamically over time and the chosen adaptation has to take into account such changes. In control theory, this type of adaptation is known as Model Predictive Control and comes with a well-developed theory and myriads of successful applications. The paper focuses on modelling the dynamic relationship between requirements and possible adaptations. It then proposes a controller that exploits this relationship to optimize the satisfaction of requirements relative to a cost-function. This is accomplished through a model-based framework for designing self-adaptive software systems that can guarantee a certain level of requirements satisfaction over time, by dynamically composing adaptation strategies when necessary. The proposed framework is illustrated and evaluated through a simulation of the Meeting-Scheduling System exemplar.
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| 2. |
- Bini, E., et al.
(författare)
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Optimal Reference Tracking for Sampled-Data Control Systems
- 2022
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Ingår i: Proceedings of the IEEE Conference on Decision and Control. - : Institute of Electrical and Electronics Engineers Inc.. - 9781665467612 ; , s. 7141-7148
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Konferensbidrag (refereegranskat)abstract
- It is a standard engineering practice to design feedback-based control to have a system follow a given trajectory. While the trajectory is continuous-time, the sequence of references is varied at discrete times as it is normally computed by digital systems.In this work, we propose a method to determine the optimal discrete-time references to be applied over a time window of a given duration. The optimality criterion is the minimization of a weighted L2 norm between the achieved trajectory and a given target trajectory which is desired to be followed. The proposed method is then assessed over different simulation results, analyzing the design parameters' effects, and over a UAV use case. The code to reproduce the results is publicly available.
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| 3. |
- Konstantinos, Angelopoulos, et al.
(författare)
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Engineering Self-Adaptive Software Systems : From Requirements to Model Predictive Control
- 2018
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Ingår i: ACM Transactions on Autonomous and Adaptive Systems. - : Association for Computing Machinery (ACM). - 1556-4665 .- 1556-4703. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Self-adaptive software systems monitor their operation and adapt when their requirements fail due to unexpected phenomena in their environment. This article examines the case where the environment changes dynamically over time and the chosen adaptation has to take into account such changes. In control theory, this type of adaptation is known as Model Predictive Control and comes with a well-developed theory and myriad successful applications. The article focuses on modeling the dynamic relationship between requirements and possible adaptations. It then proposes a controller that exploits this relationship to optimize the satisfaction of requirements relative to a cost function. This is accomplished through a model-based framework for designing self-adaptive software systems that can guarantee a certain level of requirements satisfaction over time by dynamically composing adaptation strategies when necessary. The proposed framework is illustrated and evaluated through two simulated systems, namely, the Meeting-Scheduling exemplar and an E-Shop.
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| 4. |
- Miloradović, Branko, 1987-, et al.
(författare)
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Challenges in the Automated Disassembly Process of Electric Vehicle Battery Packs
- 2023
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Ingår i: IEEE Int. Conf. Emerging Technol. Factory Autom., ETFA. - : Institute of Electrical and Electronics Engineers Inc.. - 9798350339918
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Konferensbidrag (refereegranskat)abstract
- The surge in the development and adoption of Electric Vehicles (EVs) globally is a trend many countries are paying close attention to. This inevitably means that a significant number of EV batteries will soon reach their End-of-Life (EoL). This looming issue reveals a notable challenge: there's currently a lack of sustainable strategies for managing Lithium-ion Batteries (LiBs) when they reach their EoL stage. The process of disassembling these battery packs is challenging due to their intricate design, involving several different materials and components integrated tightly for performance and safety. Consequently, effective disassembly and subsequent recycling procedures require highly specialized methods and equipment, and involve significant safety and health risks. Moreover, existing recycling technologies often fail to recover all valuable and potentially hazardous materials, leading to both economic and environmental loss. This paper provides an overview and analysis of possible challenges arising in the domain of automated battery disassembly and recycling of EV batteries that reached their EoL. We provide insight into the disassembly process as well as optimization of the disassembly sequence with the goal of minimizing the overall cost and environmental footprint.
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| 5. |
- Miloradović, Branko, 1987-, et al.
(författare)
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On the Design and Performance of a Novel Metaheuristic Solver for the Extended Colored Traveling Salesman Problem
- 2023
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Ingår i: IEEE Conf Intell Transport Syst Proc ITSC. - : Institute of Electrical and Electronics Engineers Inc.. - 9798350399462 ; , s. 1955-1962
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Konferensbidrag (refereegranskat)abstract
- Intelligent transportation systems face various challenges, including traffic congestion, environmental pollution, and inefficient transportation management. Optimizing routes and schedules for efficient delivery of goods and services can mitigate the aforementioned problems. Many transportation and routing problems can be modeled as variants of the Traveling Salesmen Problem (TSP) depending on the specific requirements of the scenario at hand. This means that to efficiently solve the routing problem, all locations have to be visited by the available salesmen in a way that minimizes the overall makespan. This becomes a non-trivial problem when the number of salesmen and locations to be visited increases. The problem at hand is modeled as a special TSP variant, called Extended Colored TSP (ECTSP). It has additional constraints when compared to the classical TSP, which further complicates the search for a feasible solution. This work proposes a new metaheuristic approach to efficiently solve the ECTSP. We compare the proposed approach to existing solutions over a series of test instances. The results show a superior performance of our metaheuristic approach with respect to the state of the art, both in terms of solution quality and algorithm's runtime.
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| 6. |
- Papadopoulos, Alessandro, et al.
(författare)
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AdaptMC : A control-theoretic approach for achieving resilience in mixed-criticality systems
- 2018
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Ingår i: Leibniz International Proceedings in Informatics, LIPIcs. - : Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing. - 9783959770750
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Konferensbidrag (refereegranskat)abstract
- A system is said to be resilient if slight deviations from expected behavior during run-time does not lead to catastrophic degradation of performance: minor deviations should result in no more than minor performance degradation. In mixed-criticality systems, such degradation should additionally be criticality-cognizant. The applicability of control theory is explored for the design of resilient run-time scheduling algorithms for mixed-criticality systems. Recent results in control theory have shown how appropriately designed controllers can provide guaranteed service to hardreal- time servers; this prior work is extended to allow for such guarantees to be made concurrently to multiple criticality-cognizant servers. The applicability of this approach is explored via several experimental simulations in a dual-criticality setting. These experiments demonstrate that our control-based run-time schedulers can be synthesized in such a manner that bounded deviations from expected behavior result in the high-criticality server suffering no performance degradation and the lower-criticality one, bounded performance degradation.
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| 7. |
- Ufua, Daniel E., et al.
(författare)
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Systemic Lean Intervention : Enhancing Lean with Community Operational Research
- 2018
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Ingår i: European Journal of Operational Research. - : ELSEVIER SCIENCE BV. - 0377-2217 .- 1872-6860. ; 268:3, s. 1134-1148
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores how theory and methodology from Community Operational Research (Community OR) can enhance Lean initiatives. We are driven by the paucity of the literature discussing the involvement of non-obvious stakeholders, particularly local communities, in the adoption of Lean. We present a project undertaken with a food production company in the Niger Delta Region of Nigeria, where we employed a Systemic Intervention methodology to integrate theory and methods from Community OR with those from Lean. Based on this example, we argue that the inclusion of community representatives is necessary if Lean waste-reduction initiatives are to benefit both organizations and their local communities. Our only proviso is that, in the spirit of Community OR, the involvement of community representatives must be meaningful, so change is agreed through stakeholder engagements that respect their inputs and framings, and do not result in organizations imposing unwanted 'solutions' on communities. The paper ends with some reflections on the added value that Community OR can offer Lean practitioners.
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