No abstract

Blockchain systems are built on top of overlay networks. While typical blockchains are based on unstructured overlays, some other blockchains utilizes structured overlays to improve the inefficiency of information propagation in unstructured overlays. However, using structured overlays have security risks such as Eclipse Attack. In this paper, we propose a method for blockchain systems to exploit a semistructured overlay with Flexible Routing Tables (FRT), so that we can obtain both communication efficiency and safety.

Blockchain is gaining attention as a technology to support cryptocurrency. However, one of the problems in using blockchain is the consumption of communication resources. It is caused by that the information received by a node can be delivered to the same node more than once through different neighbors. In this paper, we propose a method to reduce duplicate messages in a blockchain network by applying Plumtree algorithm. Through simulation experiments, we confirmed that the number of messages can be reduced by more than 70% when block propagation is simulated up to 50 blocks.

As various Internet of Things (IoT) devices have been developed, "smart remote control" products are attracting attention. A smart remote control enables controlling multiple conventional household appliances, i.e., controllable by an infrared remote control but incapable of WiFi/Bluetooth connectivity, from mobile devices like smartphones. One of the drawbacks is the difficulty of covering a whole indoor space with one smart remote control since infrared signals could be sheltered by physical obstacles such as walls, pillars, and furniture. Consequently, users are forced to control manually or install multiple smart remote controls. To solve this issue, we propose a drone-based movable smart remote control. The proposed system enables covering a broader space with a single smart remote control and makes it easy to adapt to the change in the position of household appliances. As a proof of concept, we conducted an experiment with actual devices and confirmed that the drone-based smart remote control makes infrared signals reach a wider area than placing a smart remote control on the wall.