| 1. |
- Amnell, Tobias, et al.
(författare)
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Code Synthesis for Timed Automata
- 2002
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Ingår i: Nordic Journal of Computing. - 1236-6064. ; 9:4, s. 269-300
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Amnell, Tobias, et al.
(författare)
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Code Synthesis for Timed Automata
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present a framework for development of real-time embedded systems based on the recently presented model of timed automata extended with real-time tasks. It has been shown previously that design problems such as reachability and schedulability are decidable for the model of timed automata with tasks. In this paper we describe how to automatically synthesise executable code with predictable timing behaviour, which is guaranteed to meet constraints (timing and other) imposed on the design model. To demonstrate the applicability of the framework, implemented in the Times tool, we present a case-study of a well known production cell, built in LEGO and controlled by a Hitachi H8 based LEGO Mindstorm control brick.
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| 3. |
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| 4. |
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| 5. |
- Amnell, Tobias, et al.
(författare)
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TIMES: a Tool for Schedulability Analysis and Code Generation of Real-Time Systems
- 2003
-
Ingår i: Proceedings of the International Conference of Formal Modeling and Analysis of Timed Systems. - 9783540216711
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Konferensbidrag (refereegranskat)abstract
- TIMES is a tool suite designed mainly for symbolic schedulability analysis and synthesis of executable code with predictable behaviours for real-time systems. Given a system design model consisting of(1) a set of application tasks whose executions may be required to meet mixed timing, precedence, and resource constraints,(2) a network of timed automata describing the task arrival patterns and(3) a preemptive or non-preemptive scheduling policy,TIMES will generate a scheduler, and calculate the worst case response times for the tasks. The design model may be further validated using a model checker e.g. UPPAAL and then compiled to executable C-code using the TIMES compiler. In this paper, we present the design and main features of TIMES including a summary of theoretical results behind the tool. TIMES can be downloaded at www.timestool.com.
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| 6. |
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| 7. |
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| 8. |
- Berezovskyi, Andrii, 1991-, et al.
(författare)
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Efficient state update exchange in a CPS environment for linked data-based digital twins
- 2019
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Ingår i: IEEE International Conference on Industrial Informatics (INDIN). - : Institute of Electrical and Electronics Engineers Inc.. - 9781728129273 ; , s. 983-989
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the problem of reducing the number of messages needed to exchange state updates between the Cyber-Physical System (CPS) components that integrate with the rest of the CPS through Digital Twins in order to maintain uniform communication interface and carry out their tasks correctly and safely. The main contribution is a proposed architecture and the discussion of its suitability to support correct execution of complex tasks across the CPS. A new State Event Filtering component is presented to provide event-based communication among Digital Twins that are based on the Linked Data principles while keeping the fan-out limited to ensure the scalability of the architecture.
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| 9. |
- Berezovskyi, Andrii, 1991-, et al.
(författare)
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Integrating systems of systems with a federation of rule engines
- 2024
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Ingår i: Journal of Industrial Information Integration. - : Elsevier BV. - 2467-964X .- 2452-414X. ; 38
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Tidskriftsartikel (refereegranskat)abstract
- Systems of Systems (SoSs) integrate many critical systems our society relies on. In designing individual systems, stakeholders use bespoke protocols, custom information models, and proprietary components with limited computational resources from various vendors. We present a reference architecture that allows multiple stakeholders to carry out a flexible integration without giving up control to a single entity in the presence of the aforementioned limitations. Our architecture relies on rule engines and graph data model to integrated systems flexibly even when black-box components are used. At the same time, a federation of the rule engines allows each stakeholder to retain control over the rules that reflect their policies. We also rely on a common information model based on ontologies to account for the information model mismatch and reduce the duplication of integration efforts. Moving rule execution to the standalone rule engines allows deployment in resource-constrained and proprietary environments. A uniform application programming interface (API) is used to integrate rule engines across systems as well as components within each system with a respective rule engine. We also present a novel algorithm to determine dependencies across rules deployed in different rule engines within the federation. This allows domain experts to develop rules as usual without having to deal with the distributed aspect of the system. We also present a proof of the sufficient condition to ensure all necessary notifications will be sent to ensure correct rule activation across different rule engines. Compared to other systems involving distributed rules, the proposed architecture is well-suited for the integration of transactional workloads commonly found in enterprises. The qualitative evaluation based on the Architecture Tradeoff Analysis Method (ATAM), applied to a telecommunications use case, shows that the architecture possesses the “interoperability”, “modifiability”, and the “functional completeness” quality attributes with a trade-off around rule expressiveness. The quantitative evaluation demonstrates speedup over the single-node setup in most scenarios except in case of highly optimized rules and a poor network performance simultaneously (tr<10ms, tn=100ms).
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| 10. |
- Berezovskyi, Andrii, 1991-, et al.
(författare)
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Linked Data Architecture for Plan Execution in Distributed CPS
- 2019
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Ingår i: 2019 IEEE International Conference on Industrial Technology (IEEE ICIT). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538663769 ; , s. 1393-1399
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Konferensbidrag (refereegranskat)abstract
- Future cyber-physical systems (CPS) require their components to perform autonomously. To do that safely and efficiently, CPS components will need access to the global state of the whole CPS. These components will require near real-time updates to a subset of the global state to react to changes in the environment. A particular challenge is to monitor state updates from the distributed CPS components: one needs to ensure that only states consistent with the PDDL plan execution semantics can be observed within the system. In order to guarantee that, a component to monitor plan execution is proposed. Microservices based on Linked Data technologies are used to provide a uniform way to access component states, represented as Resource Description Framework (RDF) resources. To ensure the correct ordering of state updates, we present an extension of the OASIS OSLC TRS protocol. Specifically, we strengthen the ordering guarantees of state change events and introduce inlining of the state with the events to prevent state mismatch at the dereferencing stage.
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| 11. |
- Feljan, A. V., et al.
(författare)
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Tackling IoT complexity
- 2017
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Ingår i: Ericsson Technology Review. - : Telefonaktiebolaget L.M. Ericsson. - 0014-0171. ; 95:2, s. 60-69
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Tidskriftsartikel (refereegranskat)abstract
- Internet of Things (IoT) applications transcend traditional telecom to include enterprise verticals such as transportation, healthcare, agriculture, energy and utilities. Given the vast number of devices and heterogeneity of the applications, both ICT infrastructure and IoT application providers face unprecedented complexity challenges in terms of volume, privacy, interoperability and intelligence. Cognitive automation will be crucial to overcoming the intelligence challenge.
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| 12. |
- Fersman, Elena, 1978-
(författare)
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A Generic Approach to Schedulability Analysis of Real-Time Systems
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents a framework for design, analysis, and implementation of embedded systems. We adopt a model of timed automata extended with asynchronous processes i.e. tasks triggered by events. A task is an executable program characterized by its worst-case execution time and deadline, and possibly other parameters such as priorities etc. for scheduling. The main idea is to associate each location of an automaton with a task (or a set of tasks). A transition leading to a location denotes an event triggering the tasks and the clock constraint on the transition specifies the possible arrival times of the event. This yields a model for real-time systems expressive enough to describe concurrency and synchronization, and tasks with (or without) combinations of timing, precedence and resource constraints, which may be periodic, sporadic, preemptive and (or) non-preemptive. We believe that the model may serve as a bridge between scheduling theory and automata-theoretic approaches to system modelling and analysis. Our main result is that the schedulability checking problem for this model is decidable. To our knowledge, this is the first general decidability result on dense-time models for real time scheduling without assuming that preemptions occur only at integer time points. The proof is based on a decidable class of updatable automata: timed automata with subtraction in which clocks may be updated by subtractions within a bounded zone. As the second contribution, we show that for fixed priority scheduling strategy, the schedulability checking problem can be solved by reachability analysis on standard timed automata using only two extra clocks in addition to the clocks used in the original model to describe task arrival times. The analysis can be done in a similar manner to response time analysis in classic Rate-Monotonic Scheduling. We believe that this is the optimal solution to the problem. The third contribution is an extension of the above results to deal with precedence and resource constraints. We present an operational semantics for the model, and show that the related schedulability analysis problem can be solved efficiently using the same techniques. Finaly, to demonstrate the applicability of the framework, we have modelled, analysed, and synthesised the control software for a production cell. The presented results have been implemented in the Times tool for automated schedulability analysis and code synthesis.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Fersman, Elena, et al.
(författare)
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Schedulability Analysis of Fixed-Priority Systems using Timed Automata
- 2006
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Ingår i: Theoretical Computer Science. - : Elsevier. - 0304-3975 .- 1879-2294. ; 354:2, s. 301-317
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Tidskriftsartikel (refereegranskat)abstract
- In classic scheduling theory, real-time tasks are usually assumed to be periodic, i.e. tasks are released and computed with fixed rates periodically. To relax the stringent constraints on task arrival times, we propose to use timed automata to describe task arrival patterns. In a previous work, it is shown that the general schedulability checking problem for such models is a reachability problem for a decidable class of timed automata extended with subtraction. Unfortunately, the number of clocks needed in the analysis is proportional to the maximal number of schedulable task instances associated with a model, which is in many cases huge. In this paper, we show that for fixed-priority scheduling strategy, the schedulability checking problem can be solved using standard timed automata with two extra clocks in addition to the clocks used in the original model to describe task arrival times. The analysis can be done in a similar manner to response time analysis in classic Rate-Monotonic Analysis (RMA). The result is further extended to systems with data-dependent control, in which the release time of a task may depend on the time-point at which other tasks finish their execution. For the case when the execution times of tasks are constants, we show that the schedulability problem can be solved using n+1n+1 extra clocks, where nn is the number of tasks. The presented analysis techniques have been implemented in the Times tool. For systems with only periodic tasks, the performance of the tool is comparable with tools implementing the classic RMA technique based on equation-solving, without suffering from the exponential explosion in the number of tasks.
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| 17. |
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| 18. |
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| 19. |
- Fersman, Elena, et al.
(författare)
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Schedulability Analysis using Two Clocks
- 2003
-
Ingår i: Proceedings of the International Conference on Tools and Algorithms for the Construction and Analysis of Systems. - 9783540008989
-
Konferensbidrag (refereegranskat)abstract
- In classic scheduling theory, real-time tasks are usually assumed tobe periodic, i.e. tasks arrive and compute with fixed ratesperiodically. To relax the stringent constraints on task arrivaltimes, we propose to use timed automata to describe task arrivalpatterns. In a previous work, it is shown that the generalschedulability checking problem for such models is a reachabilityproblem for a decidable class of timed automata extended withsubtraction. Unfortunately, the number of clocks needed in theanalysis is proportional to the maximal number of schedulable taskinstances associated with a model, which in many cases is huge.In this paper, we show that for fixed priority scheduling strategy,the schedulability checking problem can be solved by reachabilityanalysis on standard timed automata using only two extra clocksin addition to the clocks used in the original model to describe taskarrival times. The analysis can be done in a similar manner toresponse time analysis in classic Rate-Monotonic Scheduling.We believe that this is the optimal solution to the problem,a problem that was suspected undecidable previously.We also extend the result to systems in which the timed automata and the tasks may read and update shared data variables. Then the release time-point of a task may depend on the values of the shared variables, and hence on the time-point at which other tasks finish their exection. We show that this schedulability problem can be encoded as timed automata using n+1 extra clocks, where n is the number of tasks.
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| 20. |
- Fersman, Elena, et al.
(författare)
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Task Automata : Schedulability, Decidability and Undecidability
- 2007
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Ingår i: Information and Computation. - : Elsevier. - 0890-5401 .- 1090-2651. ; 205:8, s. 1149-1172
-
Tidskriftsartikel (refereegranskat)abstract
- We present a model, task automata, for real time systems with non-uniformly recurring computation tasks. It is an extended version of timed automata with asynchronous processes that are computation tasks generated (or triggered) by timed events. Compared with classical task models for real time systems, task automata may be used to describe tasks (1) that are generated non-deterministically according to timing constraints in timed automata, (2) that may have interval execution times representing the best case and the worst case execution times, and (3) whose completion times may influence the releases of task instances. We generalize the classical notion of schedulability to task automata. A task automaton is schedulable if there exists a scheduling strategy such that all possible sequences of events generated by the automaton are schedulable in the sense that all associated tasks can be computed within their deadlines. Our first technical result is that the schedulability for a given scheduling strategy can be checked algorithmically for the class of task automata when the best case and the worst case execution times of tasks are equal. The proof is based on a decidable class of suspension automata: timed automata with bounded subtraction in which clocks may be updated by subtractions within a bounded zone. We shall also study the borderline between decidable and undecidable cases. Our second technical result shows that the schedulability checking problem will be undecidable if the following three conditions hold: (1) the execution times of tasks are intervals, (2) the precise finishing time of a task instance may influence new task releases, and (3) a task is allowed to preempt another running task.
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| 21. |
- Fersman, Elena, et al.
(författare)
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Timed Automata with Asynchronous Processes : Schedulability and Decidability
- 2002
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we exend timed automata with asynchronous processes i.e. tasks triggered by events as a model for real-time systems. The model is expressive enough to describe concurrency and synchronization, and real time tasks which may be periodic, sporadic, preemptive or non-preemptive. We generalize the classic notion of schedulability to timed automata. An automaton is schedulable if there exists a scheduling strategy such that all possible sequences of events accepted by the automaton are schedulable in the sense that all associated tasks can be computed within their deadlines. We believe that the model may serve as a bridge between scheduling theory and automata-theoretic approaches to system modeling and analysis. Our main result is that the schedulability checking problem is decidable. To our knowledge, this is the first general decidability result on dense-time models for real time scheduling without assuming that preemptions occur only at integer time points. The proof is based on a decidable class of updatable automata: timed automata with subtraction in which clocks may be updated by subtractions within a bounded zone. The crucial observation is that the schedulability checking problem can be encoded as a reachability problem for such automata. Based on the proof, we have developed a symbolic technique and a prototype tool for schedulability analysis.
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| 22. |
- Gaspar Sánchez, José Manuel, et al.
(författare)
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Edge computing for cyber-physical systems : A Systematic Mapping Study Emphasizing Trustworthiness
- 2022
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Ingår i: ACM Transactions on Cyber-Physical Systems. - : Association for Computing Machinery (ACM). - 2378-962X .- 2378-9638. ; 6:3, s. 1-28
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Tidskriftsartikel (refereegranskat)abstract
- Edge computing is projected to have profound implications in the coming decades, proposed to provide solutions for applications such as augmented reality, predictive functionalities, and collaborative Cyber-Physical Systems (CPS). For such applications, edge computing addresses the new computational needs, as well as privacy, availability, and real-time constraints, by providing local high-performance computing capabilities to deal with the limitations and constraints of cloud and embedded systems. Edge computing is today driven by strong market forces stemming from IT/cloud, telecom, and networking - with corresponding multiple interpretations of ”edge computing” (e.g. device edge, network edge, distributed cloud, etc.). Considering the strong drivers for edge-computing and the relative novelty of the field, it becomes important to understand the specific requirements and characteristics of edge-based CPS, and to ensure that research is guided adequately, e.g. avoiding specific gaps.Our interests lie in the applications of edge computing as part of CPS, where several properties (or attributes) of trustworthiness, including safety, security, and predictability/availability are of particular concern, each facing challenges for the introduction of edge-based CPS. We present the results of a systematic mapping study, a kind of systematic literature survey, investigating the use of edge computing for CPS with a special emphasis on trustworthiness. The main contributions of this study are a detailed description of the current research efforts in edge-based CPS and the identification and discussion of trends and research gaps. The results show that the main body of research in edge-based CPS only to a very limited extent consider key attributes of system trustworthiness, despite many efforts referring to critical CPS and applications like intelligent transportation. More research and industrial efforts will be needed on aspects of trustworthiness of future edge-based CPS including their experimental evaluation. Such research needs to consider the multiple interrelated attributes of trustworthiness including safety, security, and predictability, and new methodologies and architectures to address them. It is further important to provide bridges and collaboration between edge computing and CPS disciplines.
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| 23. |
- Gürdür, Didem, 1983-, et al.
(författare)
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Knowledge Representation of Cyber-physical Systems for Monitoring Purpose
- 2018
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Ingår i: 51st CIRP Conference on Manufacturing Systems. - : Elsevier. ; , s. 468-473
-
Konferensbidrag (refereegranskat)abstract
- Automated warehouses, as a form of cyber-physical systems (CPSs), require several components to work collaboratively to address the common business objectives of complex logistics systems. During the collaborative operations, a number of key performance indicators (KPI) can be monitored to understand the proficiency of the warehouse and control the operations and decisions. It is possible to drive and monitor these KPIs by looking at both the state of the warehouse components and the operations carried out by them. Therefore, it is necessary to represent this knowledge in an explicit and formally-specified data model and provide automated methods to derive the KPIs from the representation. In this paper, we implement a minimalistic data model for a subset of warehouse resources using linked data in order to monitor a few KPIs, namely sustainability, safety and performance. The applicability of the approach and the data model is illustrated through a use case. We demonstrate that it is possible to develop minimalistic data models through Open Services for Lifecycle Collaboration (OSLC) resource shapes which enables compatibility with the declarative and procedural knowledge of automated warehouse agents specified in Planning Domain Definition Language (PDDL).
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| 24. |
- Inam, Rafia, et al.
(författare)
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Feasibility Assessment to Realise Vehicle Teleoperation using Cellular Networks
- 2016
-
Ingår i: Proceedings of the 2016 IEEE 19th International Conference on Intelligent Transportation Systems (ITSC). - IEEE.
-
Konferensbidrag (refereegranskat)abstract
- Future cellular networks (5G) will be used for a diversity of use cases. Transportation is one domain where cellular networks can play a significant role not only in connecting autonomous vehicles to other vehicles, infrastructures, and people, but also in realizing vehicle teleoperation i.e., vehicle driven by an operator from a distance. In this paper, we assess the feasibility of using a cellular network to realise vehicle teleoperation. We identify the network requirements for a teleoperated vehicle use case in an urban environment using a test setup of an LTE network and simulations. Testbed measurements reveal that teleoperation use cases can be supported even with less than excellent signal strength. Through simulation we show that the testbed can scale to cover greater distances and support teleoperation
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| 25. |
- Inam, Rafia, et al.
(författare)
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Risk Assessment for Human-Robot Collaboration in an automated warehouse scenario
- 2018
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Ingår i: 2018 IEEE 23RD INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538671085 ; , s. 743-751
-
Konferensbidrag (refereegranskat)abstract
- Collaborative robotics is recently taking an ever-increasing role in modern industrial environments like manufacturing, warehouses, mining, agriculture and others. This trend introduces a number of advantages, such as increased productivity and efficiency, but also new issues, such as new risks and hazards due to the elimination of barriers between humans and robots. In this paper we present risk assessment for an automated warehouse use case in which mobile robots and humans collaborate in a shared workspace to deliver products from the shelves to the conveyor belts. We provide definitions of specific human roles and perform risk assessment of human-robot collaboration in these scenarios and identify a list of hazards using Hazard Operability (HAZOP). Further, we present safety recommendations that will be used in risk reduction phase. We develop a simulated warehouse environment using V-REP simulator. The robots use cameras for perception and dynamically generate scene graphs for semantic representations of their surroundings. We present our initial results on the generated scene graphs. This representation will be employed in the risk assessment process to enable the use of contextual information of the robot's perceived environment, which will be further used during risk evaluation and mitigation phases and then on robots' actuation when needed.
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| 26. |
- Inam, Rafia, et al.
(författare)
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Towards Automated Service-Oriented Lifecycle Management for 5G Networks
- 2015
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Ingår i: Proceedings of the 2015 IEEE Conference on Emerging Technologies & Factory Automation (ETFA).
-
Konferensbidrag (refereegranskat)abstract
- 5G networks will be a key enabler for the Internet of Things by providing a platform to connect a massive number of devices with heterogeneous sets of network quality requirements. In this environment, 5G network operators will have to solve the complex challenge of managing network services for diverse customer sectors (such as automotive, health or energy) with different requirements throughout their lifecycle.In this paper, we present current state of our work on automating part of the network service lifecycle management using knowledge management- and decision support techniques. We also present our ongoing implementation steps for such management function in 5G networks.
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| 27. |
- Jörgensen, Nils, et al.
(författare)
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RoboPlan5G : Coordinating Cloud-Controlled Mobile Robots with 5G Network Configuration
- 2023
-
Ingår i: 2023 IEEE 28th International Conference on Emerging Technologies and Factory Automation, ETFA 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- With the emergence of Industry 4.0, comes an increasing need for multi-robot coordination and communication to efficiently complete joint tasks. A critical technology is the fifth generation (5G) mobile network, which enables cloud-controlled robots to execute tasks with differentiated quality-of-service (QoS) features. While there has been significant research on multi-robot planning, the integration with the capabilities of realistic network systems has been limited. In this paper, we introduce RoboPlan5G, a framework for 5G-aware robot planning. We propose a joint state-search model that includes task planning coordination in conjunction with 5G physical resource block (PRB) allocation. This process ensures efficient usage of the limited indoor 5G spectrum and effective service performance, while still aiming for the completion of tasks in the shortest possible time frame. Scenarios are generated in an Industry 4.0 environment, where the planner is shown to decrease the required 5G spectrum allocation by 50%, and on average improve the plan quality by 45% while maintaining a small computation time.
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| 28. |
- Jörgensen, Nils, et al.
(författare)
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Towards 5G-Aware Robot Planning for Industrial Applications
- 2022
-
Ingår i: 2022 IEEE 27th international conference on emerging technologies and factory automation (ETFA). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- With the emergence of Industry 4.0, comes an increasing need for multi-robot coordination and communication to efficiently complete joint tasks. A critical technology is the fifth generation (5G) mobile network, which enables multiple robots to execute control tasks with differentiated quality-of-service (QoS) features. However, there has been limited analysis of the impact of real 5G capabilities on multi-agent robot planning problems. In this paper, we provide a review of robot planning algorithms suitable for industrial use-cases, which consider communication aspects in the planning formulation. The paper is further positioned to identify gaps in existing state of the art within communication-aware planning. This is followed by an analysis of key challenges to be targeted at the intersection of 5G, Industry 4.0 and multi-agent robot planning. This analysis is strategically important and would prove useful to academic researchers and industry experts focusing on deployment of robots in industrial settings.
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| 29. |
- Karapantelakis, Athanasios, 1982-, et al.
(författare)
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A Deep-Q Learning Approach to Mobile Operator Collaboration
- 2020
-
Ingår i: Journal of Communications and Networks. - Seoul Korea. - 1229-2370 .- 1976-5541. ; 22:6, s. 455-466
-
Tidskriftsartikel (refereegranskat)abstract
- Next-generation mobile connectivity services include a large number of devices distributed across vast geographical areas. Mobile network operators will need to collaborate to fulfill service requirements at scale. Existing approaches to multioperator services assume already-established collaborations to fulfill customer service demand with specific quality of service (QoS). In this paper, we propose an agent-based architecture, where establishment of collaboration for a given connectivity service is done proactively, given predictions about future service demand. We build a simulation environment and evaluate our approach with a number of scenarios and in context of a real-world use case, and compare it with existing collaboration approaches. Results show that by learning how to adapt their collaboration strategy, operators can fulfill a greater part of the service requirements than by providing the service independently, or through pre-established, intangible service level agreements.
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| 30. |
- Karapantelakis, Athanasios, 1982-, et al.
(författare)
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DevOps for IoT Applications using Cellular Networks and Cloud
- 2016
-
Konferensbidrag (refereegranskat)abstract
- The Internet of Things (IoT) is a vision of a future society where an ever-increasing number of heterogeneous physical devices (“things”) obtain Internet connectivity, thus enabling a large number of applications for a broad range of industries and society at large. Mobile network operators, expected to provide the network infrastructure for many of these applications, face an unprecedented level of complexity. This complexity not only relates to the number of applications that share the network infrastructure, but also to the different network Quality of Service (QoS) requirements these application have. To achieve economies of scale, automation in management of those applications throughout their lifecycle is essential. In this paper, we propose an architecture that automates allocation, monitoring and deallocation of both cloud and cellular network resources to ensure QoS for applications that involve connected devices communicating with cloud-hosted software. We describe an implementation of this architecture using a combination of open source, commercial, and custom components and evaluate it through a series of measurements. Results show that our implementation can simultaneously support mobile broadband and low latency, high availability mission-critical applications.
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| 31. |
- Karapantelakis, Athanasios, 1982-
(författare)
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Mobile Network Operator Collaboration using Deep Reinforcement Learning
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fifth Generation Mobile Networks (5G) are designed to offer connectivity services for new types of applications that not only address the needs of private individuals, but also those of enterprise customers. Network requirements of such applications often transcend the capabilities of a single Mobile Network Operator (MNO). In such cases, the ability of MNOs to collaborate in order to provide connectivity services is essential. Existing methods for establishing collaborations between MNOs are reactive in nature and are set up using a Business Support System (BSS) that involves human decision-making. In contrast, this dissertation presents a proactive approach, which, in addition to automating collaboration establishment, uses machine learning to predict future requirements for connectivity services, and dynamically optimizes resource allocation through selection of collaborating MNOs.The analysis begins by investigating the possibility for mobile networks to support the requirements of mission-critical enterprise applications. With assistance from an automotive industry partner, a remote vehicle driving application (teleoperation) was selected and the network's requirements were quantified in terms of throughput and latency. Existing Quality of Service (QoS) mechanisms in an already-deployed mobile network were used to set up the corresponding policies, and then the performance of the connectivity service was evaluated. The evaluation is conducted within the coverage area of a single radio base station and considered a single vehicle communicating with a remote driving station. The results show that it is possible even for the current generation of mobile networks to support this type of mission-critical application.Following this quantitative assessment, wider deployments of the teleoperation application were considered, when the application's network requirements could not always be served by a single MNO. This dissertation uses deep Reinforcement Learning (RL), to build models that predict future network requirements and proactively suggest an MNO collaboration that fulfills these requirements. Experiments are conducted using two different approaches. First, a single-agent approach, wherein decisions for collaborations are provided by the model of an MNO-independent agent. In this case, all MNO share the same fairness-based policy of willingness to collaborate as long as they equally split connectivity service provisioning with their counterparts. Second, a multi-agent approach, wherein every MNO has its own agent following its own policy enforcing the terms to collaborate with other MNO. Both approaches are compared against the current state of predetermined collaboration structures or reactive collaboration approaches based on current - and unpredicted - connectivity service(s). The proposed approach is shown to provide up to a two-fold improvement in connectivity service requirement coverage over the state of art. Another benefit is resource optimization, as MNOs' capabilities are better matched to connectivity service requirements. This resource optimization can contribute to a more sustainable growth of mobile network expansion. Finally, democratization of collaborations allows for new revenue streams for smaller MNO which do not have the capacity or resources to establish collaborations in the traditional way. Although a teleoperation application and MNO mobile networks are used for the evaluation, the method and findings are expected to be applicable to a broader range of applications across different types of wireless networks.
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| 32. |
- Karapantelakis, Athanasios, 1982-, et al.
(författare)
-
Mobile Operator Collaboration Using Cooperative Multi-Agent Deep Reinforcement Learning
-
Ingår i: IEEE Internet of Things Journal. - 2327-4662.
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Tidskriftsartikel (refereegranskat)abstract
- Next generation mobile networks will provide connectivity services for an unprecedented number of mobile devices, used in industry-vertical applications with diverse network requirements as to throughput, latency, and geographical area of coverage. In order to satisfy these requirements at scale, collaboration between multiple operator is oftentimes essential. Current collaborations between network operators are long-term, reactive, and established with human involvement. The dynamic nature of mobile network traffic demands contradicts these collaborations’ rigid nature; thus, resulting in sub-optimal network resource allocation to connectivity service. In this work, we introduce an agent-based architecture for automating collaboration of mobile network operators based on predicted future demand. The architecture uses a multi-agent deep reinforcement learning algorithm, wherein every operator has its own agent suggesting future collaborations, which can change dynamically. Using simulation, we show that our approach outperforms the state of the art operator collaboration approaches and leads to more sustainable growth of mobile networks by reducing capital and operational expenses for mobile network operators.
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| 33. |
- Lv, Zhihan, et al.
(författare)
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Digital Twins : Basics and Applications
- 2022
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This book comprehensively introduces readers to Digital Twins, from the basic concepts, core technologies and technical architecture, to application scenarios and other aspects. Readers will gain a profound understanding of the emerging discipline of Digital Twins. Covering the latest and cutting-edge application technologies of Digital Twins in various fields, the book offers practitioners concrete problem-solving strategies. At the same time, it helps those working in Digital Twins-related fields to deepen their understanding of the industry and enhance their professional knowledge and skills. Given its scope, the book can also be used as teaching material or a reference book for teachers and students of product design, industrial design, design management, design marketing and related disciplines at colleges and universities. Covering a variety of groundbreaking Digital Twins technologies, it can also provide new directions for researchers.
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| 34. |
- Terra, Ahmad, et al.
(författare)
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BEERL : Both Ends Explanations for Reinforcement Learning
- 2022
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Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 12:21, s. 10947-
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Tidskriftsartikel (refereegranskat)abstract
- Deep Reinforcement Learning (RL) is a black-box method and is hard to understand because the agent employs a neural network (NN). To explain the behavior and decisions made by the agent, different eXplainable RL (XRL) methods are developed; for example, feature importance methods are applied to analyze the contribution of the input side of the model, and reward decomposition methods are applied to explain the components of the output end of the RL model. In this study, we present a novel method to connect explanations from both input and output ends of a black-box model, which results in fine-grained explanations. Our method exposes the reward prioritization to the user, which in turn generates two different levels of explanation and allows RL agent reconfigurations when unwanted behaviors are observed. The method further summarizes the detailed explanations into a focus value that takes into account all reward components and quantifies the fulfillment of the explanation of desired properties. We evaluated our method by applying it to a remote electrical telecom-antenna-tilt use case and two openAI gym environments: lunar lander and cartpole. The results demonstrated fine-grained explanations by detailing input features’ contributions to certain rewards and revealed biases of the reward components, which are then addressed by adjusting the reward’s weights.
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| 35. |
- Terra, Ahmad, et al.
(författare)
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Using Counterfactuals to Proactively Solve Service Level Agreement Violations in 5G Networks
- 2022
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Ingår i: 2022 IEEE 20TH INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 552-559
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Konferensbidrag (refereegranskat)abstract
- A main challenge of using 5G network slices is to meet all the quality of service requirements of the slices (which are agreed with the customer in a service level agreement (SLA)), throughout the network slices' lifecycle. To avoid the penalty for violation, a proactive solution is presented, including predicting the SLA violation, explaining the violation cause, and then providing an adaptation to traffic. This work uses counterfactual (CF) explanations to 1) explain the main factors affecting the identified model's SLA violation prediction and 2) present modifications in the input values, which are required to configure the network traffic to avoid such a violation. We evaluate the CF explanation at two different levels where the generated CF instance is fed to the predictive model, and then actuation data are generated to evaluate the result in the real network. Our solution minimizes the violation up to 98%. This information can be utilized to reconfigure the system, either by humans or by the system automatically, to make it fully autonomous on the one hand and comply with the 'right to explanation' introduced by the European Union's General Data Protection Regulation on the other hand.
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| 36. |
- Vulgarakis Feljan, Aneta, et al.
(författare)
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A Framework for Knowledge Management and Automated Reasoning Applied on Intelligent Transport Systems
- 2017
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Rapport (populärvet., debatt m.m.)abstract
- Cyber-Physical Systems in general, and Intelligent Transport Systems (ITS) in particular use heterogeneous data sources combined with problem solving expertise in order to make critical decisions that may lead to some form of actions e.g., driver notifications, change of traffic light signals and braking to prevent an accident. Currently, a major part of the decision process is done by human domain experts, which is time-consuming, tedious and error-prone. Additionally, due to the intrinsic nature of knowledge possession this decision process cannot be easily replicated or reused. Therefore, there is a need for automating the reasoning processes by providing computational systems a formal representation of the domain knowledge and a set of methods to process that knowledge. In this paper, we propose a knowledge model that can be used to express both declarative knowledge about the systems’ components, their relations and their current state, as well as procedural knowledge representing possible system behavior. In addition, we introduce a framework for knowledge management and automated reasoning (KMARF). The idea behind KMARF is to automatically select an appropriate problem solver based on formalized reasoning expertise in the knowledge base, and convert a problem definition to the corresponding format. This approach automates reasoning, thus reducing operational costs, and enables reusability of knowledge and methods across different domains. We illustrate the approach on a transportation planning use case.
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