Page - 166 - in Intelligent Environments 2019 - Workshop Proceedings of the 15th International Conference on Intelligent Environments

Table 1. Headphone jack specifications Item Performance Classification Headphone-jack-type dongle Input / output terminal 3.5 mm 4-pole stereo mini plug External Dimensions Length x Width x Height 25 mm x 25 mm x 8 mm * Headphone jack, excluding protrusion Electrical characteristics Input power 7.4 mW typ. Input frequency 18 22 kHz Environmental characteristics Operating ambient temperature 10 +50 No condensation Figure 3. Appearance of the headphone-jack dongle 2.3. Broof Broof is a blockchain base (substrate) on which smart contracts can be mounted [12]. Broof is a modular contract processing unit comprising loosely coupled multiple modules, making for easy protocol-level expansion. Thus, one can use a smart contract that fits specific requirements and operating environments simply via module changes. Since each node can be configured as redundant or scalable, Broof functions as a high- performance, sturdy database substrate. Figure 4 shows the modular structure of the Broof core. J.Suzuki etal. / System forMotivatingEthicalConsumptionBehavior166