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Integration of Blockchain into IoT
Published in S. Velliangiri, Sathish A. P. Kumar, P. Karthikeyan, Internet of Things, 2020
The working of blockchain goes well until only when all the peers have the same copy of ledger with them. In practical world with peers distributed across the globe, it is always highly difficult to have the same copy of the ledger in all nodes. Consensus is a process where a group of people makes a common agreement on any decision without a leader or convenor. Since blockchain is decentralized with no central authority to control, the participating nodes have to make a consensus on making all decisions. Consensus protocols make sure that the new block added to the blockchain is the only true copy, that is, being added in all peers distributed ledger. Consensus protocol mandates equal participation of all nodes in the process of coming to an agreement. This way, all nodes are given an equal chance to be a miner. Some of the consensus protocols are: Proof of work (PoW)Proof of stake (PoS)Proof of burn (PoB)Proof of capacityProof of elapsed time
Life cycle assessment in public procurement of transport infrastructure
Published in John Harvey, Imad L. Al-Qadi, Hasan Ozer, Gerardo Flintsch, Pavement, Roadway, and Bridge Life Cycle Assessment 2020, 2020
S. Toller, S. Miliutenko, M. Erlandsson, S. Nilsson, M. Larsson
In the evaluation ‘Control station 2018’ the aim was to get a deepened understanding of effects and measures implemented as a consequence of the climate requirements and to suggest a progressive development of the requirements. The evaluation considered particularly the effectiveness of the STA climate requirements in relation to the national goals, possible improvements of the bonus system and the level of GHG decrease to be required. The evaluation combined semistructured interviews with a focus group approach (Kvale 2007) that included i) workshops with stakeholders from different projects ii) workshops with different stakeholders within the same project and iii) individual interviews. In total 80 stakeholders and 16 different companies were involved. The projects were selected based on STA’s information about implemented requirements. Stakeholders (including STA stakeholders, contractors, consultants and material suppliers) were selected by snowball sampling. The results were analyzed qualitatively, based on grounded theory (Strauss & Corbin 1996). A quantitative analysis was also performed in order to understand the level of consensus between and within stakeholder groups.
Measurement in Manufacturing Ergonomics
Published in Samuel G. Charlton, Thomas G. O’Brien, Handbook of Human Factors Testing and Evaluation, 2019
In practice, the consensus-of-experts approach to the development of mapping statements and the setting of decision thresholds can work very well (see Fig. 8.4). This is especially true when the expert team is complemented by a group of domain experts who understand both the engineering constraints and the history of human capabilities in the particular work context. In some cases academic, government, and insurance company scientists may contribute to the discussion of these thresholds. In unionized organizations the mapping functions and thresholds may be established by negotiation. This process is not new; there are reports from Biblical times of negotiated labor standards and associated rewards. Another advantage ofa consensus approach is that the members of the team, who have contributed to the decision process, will generally support the resulting threshold. National and international organizations such as OSHA, American Society for Testing and Materials (ASTM), ANSI, Society of Automotive Engineers (SAE) and the International Standards Organisation (ISO) base their reputations on this consensus approach. Unfortunately, because of the complexity of the policy component of decision making, even these organizations sometimes have difficulty in reaching consensus. Consequently, the general philosophy to date in the United States has been to leave the specific engineering thresholds to individual companies, with the standards organizations limiting their influence to programmatic guidelines.
General resilient consensus algorithms
Published in International Journal of Control, 2022
Guilherme Ramos, Daniel Silvestre, Carlos Silvestre
The problem of consensus is the decision-making process, which aims to achieve agreement among members of a group. The consensus process is constrained by the communication between agents that is determined by the network topology. Therefore, the consensus value of any agent is realised as the output of a distributed algorithm. The problem of consensus is of utmost importance due to its wide range of application, and it emerges in areas such as distributed optimisation (Johansson et al., 2008; Tsitsiklis et al., 1986); motion coordination tasks like flocking, leader following (Jadbabaie et al., 2003; Liu et al., 2015); rendezvous problems (Cortés et al., 2006); resource allocation in computer networks (Chiang et al., 2007); and even in computing relative importance of webpages in the PageRank algorithm (Silvestre et al., 2018). More than arising in several areas, consensus additionally emerges as a key subproblem of essential applications. For instance, to estimate the motion of a target in two-dimensional space, as in the case in Olfati-Saber (2007), where authors developed a Distributed Kalman Filter based on two systems of consensus. This work was experimentally evaluated to estimate the motion of a real robot in Alriksson and Rantzer (2007).
A framework for rocket and satellite launch information management systems based on blockchain technology
Published in Enterprise Information Systems, 2021
In an information management system based on the proposed framework, information related to a rocket or satellite will be collected and sent to confirmation nodes. The confirmation nodes write to the blockchain in accordance with a consensus mechanism. The meaning of the word ‘consensus’ here is different from its meaning in the context of group decision making (Cai et al. 2016). In the proposed framework, the consensus mechanism is the method by which the nodes in the network reach consensus through voting by special nodes, thus allowing the verification and confirmation of transactions to be completed in a very short time (Mingxiao et al. 2017). The blockchain structure used in the proposed framework is a consortium chain. The participants in the system have strong credibility, so there are few malicious behaviours. Each participant can provide a safe, reliable and stable operating environment. Therefore, this environment is suitable for the Practical Byzantine Fault Tolerance (PBFT) consensus algorithm (Sukhwani et al. 2017). The system will first select a primary node and send blocks to this primary node based on a sorted list of nodes. The primary node broadcasts each block in the corresponding channel, and when most of the nodes in the channel have verified a block, that block is appended to the blockchain.
Two new methods for decision-making with incomplete reciprocal fuzzy preference relations based on additive consistency
Published in International Journal of Modelling and Simulation, 2021
Aqeel Asaad Al Salem, Anjali Awasthi
For future work, the consensus process will be considered, since in any group decision-making, reaching to a consensus level is important. In addition, a method based on multiplicative consistency will be introduced to solve the ignorance situation. Multiplicative transitivity will be considered, as it is as important as the additive transitivity per the literature. The main difference between them is that the additive transitivity is based on preference degrees mapped to the domain . While in multiplicative transitivity there are several numerical scales, however, the most popular one is the 1–9 Saaty scale. Moreover, this work will be extended to find a solution for incomplete preference relations with initial inconsistent information by detecting the most inconsistent preference degree(s) that affects the consistency level and adjusts it.