The effect of singers masks on the impulse dispersion of aerosols during singing

Background: During the Covid-19 pandemic, singing activities were restricted due to several super-spreading events which have been observed during rehearsals and vocal performances. However, it has not been clarified how the aerosol dispersion, which has been assumed to be the leading transmission factor, could be reduced by masks which are specially designed for singers. Material and Methods: 12 professional singers (10 of the Bavarian Radio-Chorus and two freelancers, 7 females and 5 males) were asked to sing the melody of the ode of joy of Beethovens 9. symphony Freude schoener Goetterfunken, Tochter aus Elysium in D-major without masks and afterwards with five different singers masks, all distinctive in their material and proportions. Every task was conducted after inhaling the basic liquid from an e-cigarette. The aerosol dispersion was recorded by three high-definition video cameras during and after the task. The cloud was segmented and the dispersion was analyzed for all three spatial dimensions. Further, the subjects were asked to rate the practicability of wearing the tested masks during singing activities using a questionnaire. Results: Concerning the median distances of dispersion, all masks were able to decrease the impulse dispersion of the aerosols to the front. In contrast, the dispersion to the sides and to the top was increased. The evaluation revealed that most of the subjects would reject performing a concert with any of the masks. Conclusion: Although, the results exhibit that the tested masks could be able to reduce the radius of aerosol expulsion for virus-laden aerosol particles, there are more improvements necessary to enable the practical implementations for professional singing.

Empirical Results for High-definition Video and Augmented Reality Content Delivery in Hyper-connected Cars

Software architecture and applications for the connected car can process and share a variety of digital content, among which high-definition video and augmented reality (AR) content, toward enhanced driving assistance, navigation and infotainment systems and services. However, several technical challenges need to be overcome to make such systems and services viable and efficient, including dealing effectively with a variety of types of systems, devices and platforms, either installed inside the vehicle or represented by the personal mobile and wearable devices of the drivers and passengers. In this paper, we outline these technical challenges and propose a software solution in the form of an event-based middleware layer by modeling the smart, connected car as a specific type of a smart environment. We employ an adapted version of Euphoria, a recently introduced software architecture for general-purpose smart environments, to implement asynchronous communications among heterogeneous input/output devices inside the vehicle. We also adapt Euphoria to fit into the four-layer infrastructure model of the connected car. We conduct a technical evaluation of the request-response time performance achieved with the Euphoria middleware for streaming digital content from 1 Mbps (360p@30fps) to 32 Mbps (4K@30fps) on various devices, either integrated in the vehicle, not integrated but used inside the vehicle and devices outside the vehicle (the control condition). Our results show effective live streaming achieved for 2K content at 30fps with the 600 Mbps network (i.e., the connected car) and for 4K content at 30fps with the 1.7 Gbps network envisioned for hyper-connected vehicles. These results open up opportunities for high-definition video and AR applications in the automotive industry.