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- Johansson, B., et al.
(författare)
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Consistency before Availability : Network Reference Point based Failure Detection for Controller Redundancy
- 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
- Distributed control systems constitute the automation solution backbone in domains where downtime is costly. Redundancy reduces the risk of faults leading to unplanned downtime. The Industry 4.0 appetite to utilize the device-to-cloud continuum increases the interest in network-based hardware-agnostic controller software. Functionality, such as controller redundancy, must adhere to the new ground rules of pure network dependency. In a standby controller redundancy, only one controller is the active primary. When the primary fails, the backup takes over. A typical network-based failure detection uses a cyclic message with a known interval, a.k.a. a heartbeat. Such a failure detection interprets heartbeat absences as a failure of the supervisee; consequently, a network partitioning could be indistinguishable from a node failure. Hence, in a network partitioning situation, a conventional heartbeat-based failure detection causes more than one active controller in the redundancy set, resulting in inconsistent outputs. We present a failure detection algorithm that uses network reference points to prevent network partitioning from leading to dual primary controllers. In other words, a failure detection that prioritizes consistency before availability.
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| 2. |
- Stigson, Peter, 1974-
(författare)
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The industry role in policymaking : Policy learning in climate politics
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Climatic change has sparked a broad range of responses on all societal levels. New initiatives and negotiations, scientific findings, and technological developments, have established a novel framework for policymaking and industrial abatement investments. Lessons on the evolving framework should be analysed and utilised to handle the dynamic reality of climate policymaking processes. Governments in the majority of economies only have an indirect and long-term influence on reducing industrial emissions, as they do not own the emitting operations. As representing one-third of the global carbon dioxide emissions, industry is therefore a key stakeholder group in whether or not the political agenda will be fulfilled. How industry perceives that obstacles and opportunities affect investment calculi are thus important. Hence, policymakers should facilitate policy learning (PL) to aid the creation of effective and efficient political agendas. This is important to acknowledge the policy and investment experiences of industrial actors and to deal with a number of plausible investment obstacles identified under the novel framework. Taking stock of PL and other policy theories, this thesis is aimed to develop recommendations for facilitating PL and thus contributing to more effective and efficient climate policy frameworks. The results highlight the role of industry in abatement and political strategies where policymakers need to gain knowledge on how industries perceive abatement investment obstacles and how these may be bridged. The intrinsic learning values of government-industry negotiated agreements (NAs) are emphasised and a framework for operationalising PL through NA designs is developed. PL is furthermore identified as important, and NAs are recommended as a policy instrument, to fill knowledge gaps identified in two case-studies of promoting complex and novel industrial operations. This thesis also recommends a participatory policy evaluation tool that is sensitive to industrial competitiveness and establishes a forum for discussions on perceived investment obstacles and opportunities under different conditions. The results are not aimed to provide a blueprint for a comprehensive climate policy framework but as a contribution to literature and the incremental learning that this thesis strongly promotes.
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