SimBlock: A Blockchain Network Simulator

Blockchain, which is a technology for distributedly managing ledger information over multiple nodes without a centralized system, has elicited increasing attention. Performing experiments on actual blockchains are difficult because a large number of nodes in wide areas are necessary. In this study, we developed a blockchain network simulator SimBlock for such experiments. Unlike the existing simulators, SimBlock can easily change behavior of node, so that it enables to investigate the influence of nodes' behavior on blockchains. We compared some simulation results with the measured values in actual blockchains to demonstrate the validity of this simulator. Furthermore, to show practical usage, we conducted two experiments which clarify the influence of neighbor node selection algorithms and relay networks on the block propagation time. The simulator could depict the effects of the two techniques on block propagation time. The simulator will be publicly available in a few months.Comment: Proc. 2nd Workshop on Cryptocurrencies and Blockchains for Distributed Systems (CryBlock 2019) (in conj. with INFOCOM 2019

Photocontrol over Cooperative Porphyrin Self-Assembly with Phenylazopyridine Ligands

Die kooperative Selbstorganisation chiraler Zinkporphyrine wird durch einen photoresponsiven Phenylazopyridin-Ligand (1) gesteuert. Die Porphyrinstapel depolymerisieren zu Dimeren, wenn dieser Ligand in axialer Stellung koordiniert, und die Stärke dieser Koordination wird durch die photoinduzierte Isomerisierung des Liganden kontrolliert, bei der für beide Zustände Umsatzverhältnisse über 95¿% erzielt werden