Robust and cheating-resilient power auctioning on Resource Constrained Smart Micro-Grids

The principle of Continuous Double Auctioning (CDA) is known to provide an efficient way of matching supply and demand among distributed selfish participants with limited information. However, the literature indicates that the classic CDA algorithms developed for grid-like applications are centralised and insensitive to the processing resources capacity, which poses a hindrance for their application on resource constrained, smart micro-grids (RCSMG). A RCSMG loosely describes a micro-grid with distributed generators and demand controlled by selfish participants with limited information, power storage capacity and low literacy, communicate over an unreliable infrastructure burdened by limited bandwidth and low computational power of devices. In this thesis, we design and evaluate a CDA algorithm for power allocation in a RCSMG. Specifically, we offer the following contributions towards power auctioning on RCSMGs. First, we extend the original CDA scheme to enable decentralised auctioning. We do this by integrating a token-based, mutual-exclusion (MUTEX) distributive primitive, that ensures the CDA operates at a reasonably efficient time and message complexity of O(N) and O(logN) respectively, per critical section invocation (auction market execution). Our CDA algorithm scales better and avoids the single point of failure problem associated with centralised CDAs (which could be used to adversarially provoke a break-down of the grid marketing mechanism). In addition, the decentralised approach in our algorithm can help eliminate privacy and security concerns associated with centralised CDAs. Second, to handle CDA performance issues due to malfunctioning devices on an unreliable network (such as a lossy network), we extend our proposed CDA scheme to ensure robustness to failure. Using node redundancy, we modify the MUTEX protocol supporting our CDA algorithm to handle fail-stop and some Byzantine type faults of sites. This yields a time complexity of O(N), where N is number of cluster-head nodes; and message complexity of O((logN)+W) time, where W is the number of check-pointing messages. These results indicate that it is possible to add fault tolerance to a decentralised CDA, which guarantees continued participation in the auction while retaining reasonable performance overheads. In addition, we propose a decentralised consumption scheduling scheme that complements the auctioning scheme in guaranteeing successful power allocation within the RCSMG. Third, since grid participants are self-interested we must consider the issue of power theft that is provoked when participants cheat. We propose threat models centred on cheating attacks aimed at foiling the extended CDA scheme. More specifically, we focus on the Victim Strategy Downgrade; Collusion by Dynamic Strategy Change, Profiling with Market Prediction; and Strategy Manipulation cheating attacks, which are carried out by internal adversaries (auction participants). Internal adversaries are participants who want to get more benefits but have no interest in provoking a breakdown of the grid. However, their behaviour is dangerous because it could result in a breakdown of the grid. Fourth, to mitigate these cheating attacks, we propose an exception handling (EH) scheme, where sentinel agents use allocative efficiency and message overheads to detect and mitigate cheating forms. Sentinel agents are tasked to monitor trading agents to detect cheating and reprimand the misbehaving participant. Overall, message complexity expected in light demand is O(nLogN). The detection and resolution algorithm is expected to run in linear time complexity O(M). Overall, the main aim of our study is achieved by designing a resilient and cheating-free CDA algorithm that is scalable and performs well on resource constrained micro-grids. With the growing popularity of the CDA and its resource allocation applications, specifically to low resourced micro-grids, this thesis highlights further avenues for future research. First, we intend to extend the decentralised CDA algorithm to allow for participants’ mobile phones to connect (reconnect) at different shared smart meters. Such mobility should guarantee the desired CDA properties, the reliability and adequate security. Secondly, we seek to develop a simulation of the decentralised CDA based on the formal proofs presented in this thesis. Such a simulation platform can be used for future studies that involve decentralised CDAs. Third, we seek to find an optimal and efficient way in which the decentralised CDA and the scheduling algorithm can be integrated and deployed in a low resourced, smart micro-grid. Such an integration is important for system developers interested in exploiting the benefits of the two schemes while maintaining system efficiency. Forth, we aim to improve on the cheating detection and mitigation mechanism by developing an intrusion tolerance protocol. Such a scheme will allow continued auctioning in the presence of cheating attacks while incurring low performance overheads for applicability in a RCSMG

Programming with process groups: Group and multicast semantics

Process groups are a natural tool for distributed programming and are increasingly important in distributed computing environments. Discussed here is a new architecture that arose from an effort to simplify Isis process group semantics. The findings include a refined notion of how the clients of a group should be treated, what the properties of a multicast primitive should be when systems contain large numbers of overlapping groups, and a new construct called the causality domain. A system based on this architecture is now being implemented in collaboration with the Chorus and Mach projects

Investigating the Decentralized Governance of Distributed Ledger Infrastructure Implementation in Extended Enterprises

publishedVersio

Engineering framework for service-oriented automation systems

Tese de doutoramento. Engenharia Informática. Universidade do Porto. Faculdade de Engenharia. 201

Blockchain for humanitarian aid

Blockchain technology has proven to be an effective tool to increase performance in for-profit supply chains. Yet, we lack deep understanding of its impact on the humanitarian supply chain. This thesis aims at addressing this gap through a qualitative research. Evidence from expert interviews and secondary reports suggests that blockchain technology positively impacts the information and resource flow in humanitarian supply chains by either replacing traditional intermediaries or enhancing transparency. It further reveals that the impact on supply chain actors is very individual. Donors can particularly benefit from the increased transparency as this empowers them to track their donations. Humanitarian organizations can improve their internal efficiencies and enhance their collaboration with external stakeholders. For beneficiaries, blockchain technology offers a new infrastructure to access humanitarian services which are more dignified and empowering. The empirical findings of this thesis enhance our general understanding of blockchain technology in the humanitarian sector. Furthermore, this research provides concrete strategies for humanitarian organizations to leverage the full potential of blockchain technology. Thus, it is of particular relevance for humanitarians aiming to address current challenges in the humanitarian supply chain.A tecnologia blockchain provou ser uma ferramenta eficaz para melhorar a performance das cadeias de abastecimento. No entanto, não existe um entendimento profundo do seu impacto na cadeia de abastecimento humanitária. Esta tese visa abordar essa lacuna através de uma pesquisa qualitativa. Entrevistas realizadas com especialistas e relatórios secundários sugerem que a tecnologia blockchain afecta positivamente o fluxo de informações e recursos nas cadeias de abastecimento humanitárias, substituindo os intermediários tradicionais ou aumentando a transparência. Além disso, revela que o impacto sobre os actores da cadeia de abastecimento é muito individual. Os doadores beneficiam do aumento da transparência, pois melhora a capacidade de monitorização das doações. As organizações humanitárias podem incrementar a eficiência interna e aprimorar a sua colaboração com as partes interessadas. Para os beneficiários, a blockchain oferece uma nova infra-estrutura para tornar os serviços humanitários mais dignos e com maior impacto. As descobertas empíricas desta tese fortalecem o entendimento geral do impacto da TBC no sector humanitário. Adicionalmente, esta pesquisa fornece estratégias concretas para as organizações humanitárias aproveitarem todo o potencial da tecnologia blockchain, sendo particularmente relevante para ultrapassar os desafios actuais na cadeia de abastecimento humanitária