Synchronous hybrid learning allows physically distributed students and teachers to participate simultaneously in learning activities. Despite the growing interest in synchronous hybrid learning, there remains a need for further investigation into effective pedagogical approaches and technological implementations that support teacher-student interactions at the school level. Addressing this, we present a prototype of an in-house holographic telepresence environment for synchronous hybrid learning, demonstrated through an exploratory study connecting students and teachers across two continents. We conducted semi-structured interviews with the six participating teachers to understand their experiences and perceptions related to the application of holographic telepresence for synchronous hybrid learning. Thematic analysis of the interview data highlights the pedagogical challenges that teachers faced, identifies technological environment design improvements, and outlines new opportunities for enhancing synchronous hybrid learning experiences. This research contributes to the ongoing discourse on leveraging immersive technologies to enhance education in diverse and geographically separated settings.

Unmanned underwater vehicles are crucial for deep-sea exploration and inspection without imposing any danger to human life due to extreme environmental conditions. But, designing a robust controller that can cope with model uncertainties, external disturbances, and time delays for such vehicles is a challenge. This paper implements a sliding mode position control algorithm with a time-delay estimation term to a remotely operated underwater vehicle to deal with disturbances, such as waves, and time delays. The controller is implemented on an underwater vehicle (BlueRov) and compared with a proportional-integral-derivative (PID) controller in a wave tank with different disturbances and when there exist delays within the communication channel. The experimental results show that the proposed control method provides better performance than the conventional PID in the presence of extreme disturbances with less control efforts.