| 1. |
- Balador, Ali, et al.
(författare)
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Wireless communication technologies for safe cooperative cyber physical systems
- 2018
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 18:11
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative Cyber-Physical Systems (Co-CPSs) can be enabled using wireless communication technologies, which in principle should address reliability and safety challenges. Safety for Co-CPS enabled by wireless communication technologies is a crucial aspect and requires new dedicated design approaches. In this paper, we provide an overview of five Co-CPS use cases, as introduced in our SafeCOP EU project, and analyze their safety design requirements. Next, we provide a comprehensive analysis of the main existing wireless communication technologies giving details about the protocols developed within particular standardization bodies. We also investigate to what extent they address the non-functional requirements in terms of safety, security and real time, in the different application domains of each use case. Finally, we discuss general recommendations about the use of different wireless communication technologies showing their potentials in the selected real-world use cases. The discussion is provided under consideration in the 5G standardization process within 3GPP, whose current efforts are inline to current gaps in wireless communications protocols for Co-CPSs including many future use cases.
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| 2. |
- Eiter, Thomas, et al.
(författare)
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ALASPO : An Adaptive Large-Neighbourhood ASP Optimiser
- 2022
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Ingår i: KR 2022. - : IJCAI Organization. - 9781956792010 ; , s. 565-569
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Konferensbidrag (refereegranskat)abstract
- We present the system ALASPO which implements Adaptive Large-neighbourhood search for Answer Set Programming (ASP) Optimisation. Large-neighbourhood search (LNS) is a meta-heuristic where parts of a solution are destroyed and reconstructed in an attempt to improve an overall objective. ALASPO currently supports the ASP solver clingo, as well as its extensions clingo-dl and clingcon for difference and full integer constraints, and multi-shot solving for an efficient implementation of the LNS loop. Neighbourhoods can be defined in code or declaratively as part of the ASP encoding. While the method underlying ALASPO has been described in previous work, ALASPO also incorporates portfolios for the LNS operators along with self-adaptive selection strategies as a technical novelty. This improves usability considerably at no loss of solution quality, but on the contrary often yields benefits. To demonstrate this, we evaluate ALASPO on different optimisation benchmarks.
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| 3. |
- Eiter, Thomas, et al.
(författare)
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An open challenge for exact job scheduling with reticle batching in photolithography
- 2022
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Konferensbidrag (refereegranskat)abstract
- We consider scheduling solutions for photolithography, an important sub-task in semi-conductor production, where patterns are transferred to wafers using reticles. The problem can be modelled as job scheduling on unrelated parallel machines with sequence-dependent setup times and release dates. The reticles add auxiliary-resource constraints for processing jobs. Equipping machines with the right reticles using transport robots from stockers in time renders this problem extremely difficult for exact solvers that use a declarative model. The latter would be attractive as such models tend to be compact and easy to maintain. We present a solver-independent MiniZinc model and provide 500 new benchmark instances. However, only small instances can be solved with state-of-the-art MIP and CP solvers. Consequently, we present this problem as an open challenge with considerable potential for driving improvements towards industrial applications.
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| 4. |
- Eiter, Thomas, et al.
(författare)
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Answer-Set Programming for Lexicographical Makespan Optimisation in Parallel Machine Scheduling
- 2021
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Ingår i: Proceedings of the 18th International Conference on Principles of Knowledge Representation and Reasoning, KR 2021. - : IJCAI Organization. - 9781956792997 ; , s. 280-290
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Konferensbidrag (refereegranskat)abstract
- We deal with a challenging scheduling problem on parallel-machines with sequence-dependent setup times and release dates from a real-world application of semiconductor workshop production. There, jobs can only be processed by dedicated machines, thus few machines can determine the makespan almost regardless of how jobs are scheduled on the remaining ones. This causes problems when machines fail and jobs need to be rescheduled. Instead of optimising only the makespan, we put the individual machine spans in non-ascending order and lexicographically minimise the resulting tuples. This achieves that all machines complete as early as possible and increases the robustness of the schedule. We study the application of Answer-Set Programming (ASP) to solve this problem. While ASP eases modelling, the combination of timing constraints and the considered objective function challenges current solving technology. The former issue is addressed by using an extension of ASP by difference logic. For the latter, we devise different algorithms that use multi-shot solving. To tackle industrial-sized instances, we study different approximations and heuristics. Our experimental results show that ASP is indeed a promising KRR paradigm for this problem and is competitive with state-of-the-art CP and MIP solvers.
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| 5. |
- Eiter, Thomas, et al.
(författare)
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Answer-Set Programming for Lexicographical Makespan Optimisation in Parallel Machine Scheduling
- 2023
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Ingår i: Theory and Practice of Logic Programming. - : Cambridge University Press. - 1471-0684 .- 1475-3081. ; 23:6, s. 1281-1306
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Tidskriftsartikel (refereegranskat)abstract
- We deal with a challenging scheduling problem on parallel machines with sequence-dependent setup times and release dates from a real-world application of semiconductor work-shop production. There, jobs can only be processed by dedicated machines, thus few machines can determine the makespan almost regardless of how jobs are scheduled on the remaining ones. This causes problems when machines fail and jobs need to be rescheduled. Instead of optimising only the makespan, we put the individual machine spans in non-ascending order and lexicographically minimise the resulting tuples. This achieves that all machines complete as early as possible and increases the robustness of the schedule. We study the application of answer-set programming (ASP) to solve this problem. While ASP eases modelling, the combination of timing constraints and the considered objective function challenges current solving technology. The former issue is addressed by using an extension of ASP by difference logic. For the latter, we devise different algorithms that use multi-shot solving. To tackle industrial-sized instances, we study different approximations and heuristics. Our experimental results show that ASP is indeed a promising knowledge representation and reasoning (KRR) paradigm for this problem and is competitive with state-of-the-art constraint programming (CP) and Mixed-Integer Programming (MIP) solvers.
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| 6. |
- Eiter, Thomas, et al.
(författare)
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Large-Neighbourhood Search for ASP Optimisation
- 2022
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Ingår i: Electronic Proceedings in Theoretical Computer Science, EPTCS. - : Open Publishing Association. ; , s. 163-165
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Konferensbidrag (refereegranskat)abstract
- While answer-set programming (ASP) is a successful approach to declarative problem solving optimisation can still be a challenge for it. Large-neighbourhood search (LNS) is a metaheuristic technique where parts of a solution are alternately destroyed and reconstructed, which has high but untapped potential for ASP solving. We present a framework for LNS optimisation for ASP, in which neighbourhoods can be specified either declaratively as part of the ASP encoding, or automatically generated by code. In the full paper, we illustrate the framework on different optimisation problems, some of which are notoriously difficult, including shift planning and a parallel machine scheduling problem from semi-conductor production which demonstrate the effectiveness of the LNS approach.
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| 7. |
- Eiter, Thomas, et al.
(författare)
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Large-Neighbourhood Search for Optimisation in Answer-Set Solving
- 2022
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Ingår i: Proceedings of the 36th AAAI Conference on Artificial Intelligence, AAAI 2022. - : Association for the Advancement of Artificial Intelligence. - 1577358767 - 9781577358763 ; , s. 5616-5625
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Konferensbidrag (refereegranskat)abstract
- While Answer-Set Programming (ASP) is a prominent approach to declarative problem solving, optimisation problems can still be a challenge for it. Large-Neighbourhood Search (LNS) is a metaheuristic for optimisation where parts of a solution are alternately destroyed and reconstructed that has high but untapped potential for ASP solving. We present a framework for LNS optimisation in answer-set solving in which neighbourhoods can be specified either declaratively as part of the ASP encoding or automatically generated by code. To effectively explore different neighbourhoods, we focus on multi-shot solving as it allows to avoid program regrounding. We illustrate the framework on different optimisation problems some of which are notoriously difficult, including shift planning and a parallel machine scheduling problem from semi-conductor production, which demonstrate the effectiveness of the LNS approach.
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| 8. |
- Lindgren, Anna, et al.
(författare)
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Individual whole-body concentration of (137)Cesium is associated with decreased blood counts in children in the Chernobyl-contaminated areas, Ukraine, 2008-2010.
- 2015
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Ingår i: Journal of Exposure Science & Environmental Epidemiology. - : Springer Science and Business Media LLC. - 1559-064X .- 1559-0631. ; 25:3, s. 334-342
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Tidskriftsartikel (refereegranskat)abstract
- The Narodichesky region, Zhitomir Oblast, Ukraine, is situated ∼80 km from the Chernobyl Nuclear Power Plant, which exploded in 1986 and polluted the environment. A previous study found that children living in villages with high activity of (137)Cesium (Cs) in the soil had decreased levels of hemoglobin, erythrocytes and thrombocytes. These findings motivated the present study that used a more comprehensive exposure assessment, including individual whole-body concentrations (WBC) of (137)Cs (Bq/kg). This cross-sectional sample examined between 2008-2010, included 590 children in the age 0-18 years. Children with higher individual log(WBC) activity in the body had significantly decreased hemoglobin, erythrocyte and thrombocyte counts. The effect of log(WBC) on decreased thrombocyte count was only seen in children older than 12 years. The average village activity of (137)Cs (kBq/m(2)) in soil was associated with decreased blood counts only indirectly, through (137)Cs in the body as an intermediate variable. Children in this study were born at least 4 years after the accident and thus exposed to low doses of ionizing radiation from (137)Cs. This cross-sectional study indicates that low levels may be associated with decreased blood counts, but we cannot exclude that these results are due to residual confounding factors.Journal of Exposure Science and Environmental Epidemiology advance online publication, 25 September 2013; doi:10.1038/jes.2013.60.
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