Abstract: A surgical helmet assembly can be securable to a mixed reality device and can include an inner frame, an outer frame, and a surgical hood. The inner frame can be securable to the mixed reality device. The outer frame can be releasably securable to the inner frame, where at least a portion of a lens of the mixed reality device exposed through the inner frame and the outer frame. The surgical hood can be connected to the outer frame and can be configured to cover at least a portion of a head of a user.

Abstract: A bi-directional line switched mesh includes at least one bi-directional line switched ring (BLSR) sharing a common section with a partial bi-directional line switched ring (PBLSR). The partial bi-directional line switched ring has no working traffic along the common section, but may utilize the protection bandwidth associated with the common section of the BLSR in the event of a span failure of the PBLSR. Both electrical and optical PBLSR networks are also disclosed including methods of operating the asymmetrical ring nodes having unconfigured working ports (spans).