A communication system includes a host device and a peripheral device which are communicate with each other according to a main communication protocol that allows the command to be transmitted only from the host device to the peripheral device. The bone attachment devices include a head with socket to receive a spinal rod or other elongate element and the crosslink device includes a pair of bridging members each having an end section for connecting with the bone attachment devices. Segment boundaries may be adaptive by determining them according to criteria, by dividing streamed content into segments, andor by processing the content based on the content data to determine split points. A transparent cover composed of a flat and smooth plate is arranged over the output surface of the resin lens array and a metal retainer is attached to the transparent cover so that a pressing pressure is always applied to the resin lens array. The fluid is then returned to the HRSG immediately downstream from the point from which it was drawn. The frame structure supports a generally plate-shaped sunscreen, and the sun screen can be attached to the frame structure in a movable manner by a guide device.