A dataset of ambient sensors in a meeting room for activity recognition.

As IoT technology advances, using machine learning to detect user activities emerges as a promising strategy for delivering a variety of smart services. It is essential to have access to high-quality data that also respects privacy concerns and data streams from ambient sensors in the surrounding environment meet this requirement. However, despite growing interest in research, there is a noticeable lack of datasets from ambient sensors designed for public spaces, as opposed to those for private settings. To bridge this gap, we design the DOO-RE dataset within an actual meeting room environment, equipped with three types of ambient sensors: those triggered by actuators, users, and the environment itself. This dataset is compiled from the activities of over twenty students throughout a period of four months. DOO-RE provides reliable and purpose-oriented activity data in a public setting, with activity labels verified by multiple annotators through a process of cross-validation to guarantee data integrity. DOO-RE categorizes nine different types of activities and facilitates the study of both single and group activities. We are optimistic that DOO-RE will play a significant role in advancing human activity recognition technologies, enhancing smart automation systems, and enabling the rapid setup of smart spaces through ambient sensors.

A Hybrid Jamming Structure Combining Granules and a Chain Structure for Robotic Applications.

To allow versatile manipulation of soft robots made of compliant materials with limited force transmission, variable stiffness has been actively developed, which has become one of the most important factors in soft robotics. Variable stiffness is usually achieved by a jamming mechanism using layers, granules, or chain structures, through vacuum pressure or cable-driven mechanism due to its simple and rapid actuation. However, such jamming mechanisms are not suitable for actual robotic applications that require large supporting forces or drastic changes in stiffness. In this article, a hybrid jamming structure that combines granules and a rigid chain structure is proposed to simultaneously increase the average stiffness change in all directions and the maximum force in a certain direction. The improved performance of the proposed structure was compared to that of conventional granular and chain jamming structures. Based on the analytical model of the proposed structure, the principles for designing the hybrid jamming structure were derived and experimentally verified. Finally, based on the hybrid jamming structures, a multilink hybrid jamming structure was developed as a wearable system to assist the upper limbs and a robotic arm structure.