NII Shonan Meeting Report No . 2015 - 3 National Institute of Informatics 2 - 1 - 2 Hitotsubashi , Chiyoda - Ku , Tokyo , Japan Systems Resilience - Bridging the Gap Between Social and Mathematical Hiroshi Maruyama Günter

This two-fold presentation will discuss the Cyber-Physical-Systems (CPS) framework in light of these incidents, as well as position the incidents within an over-all resilience concept while making connections to various resilience techniques. Discussion. Cognizant of the fact that resilience has been defined by various disciplines (e.g., social, ecological, biological, and engineering) and in different application domains, but most of the time partial and overlapping, a taxonomy and set of strategies for general resilience were presented to contextualize resilience. The presentation also highlighted a Systems Resilience (SR) model that can be viewed as a two-player, i.e., system and attacker (e.g., perturbations and disaster) game theoretic framework, where the goal is the system being resilient over the attacker. The presentation was able to elucidate how the SR model can be applied in the cyber-physical (as the system) domain. Resilience of cryptocurrencies Christian Brenig, The University of Freiburg Abstract. Cryptocurrencies, like Bitcoin, are intended as innovative means to conduct transactions and are even considered as substitute for traditional fiat based currencies by some proponents. Our ongoing research is targeted at the economic opportunities and challenges associated with cryptocurrencies. How resilient are they against threats and attacks from inside and outside the system? Do they have the potential to serve as currency? Discussion. The discussion centered on the three roles of currency, namely, account, exchange, and store, and the threat to these roles could include volatility, theft, and trust. Among the three, the issue of trust was highlighted as it related to discussions on beneficiary perceptions of the system. Cryptocurrencies, like Bitcoin, are intended as innovative means to conduct transactions and are even considered as substitute for traditional fiat based currencies by some proponents. Our ongoing research is targeted at the economic opportunities and challenges associated with cryptocurrencies. How resilient are they against threats and attacks from inside and outside the system? Do they have the potential to serve as currency? Discussion. The discussion centered on the three roles of currency, namely, account, exchange, and store, and the threat to these roles could include volatility, theft, and trust. Among the three, the issue of trust was highlighted as it related to discussions on beneficiary perceptions of the system. Bitcoin: the reason why the decentralized currency achieves justice as fairness Hitoshi Okada, National Institute of Informatics Abstract. Bitcoin is a decentralized virtual currency based on P2P technology. It enables the unique distribution of electronic value from one person to another without the existence of a centralized issuer. Virtual currency circulates in an open-looped system as if it were real money, whereas existing electronic money circulates in a closed-looped system. The decentralization issue of virtual currency raises a question concerning the seigniorage profit, which ought to be under state monopoly. This presentation discusses the state for what reason currency issuance should be decentralized. We also discuss the ideal public Bitcoin is a decentralized virtual currency based on P2P technology. It enables the unique distribution of electronic value from one person to another without the existence of a centralized issuer. Virtual currency circulates in an open-looped system as if it were real money, whereas existing electronic money circulates in a closed-looped system. The decentralization issue of virtual currency raises a question concerning the seigniorage profit, which ought to be under state monopoly. This presentation discusses the state for what reason currency issuance should be decentralized. We also discuss the ideal public