Michael Finkenzeller

Routing in Mobile Ad-hoc and Peer-to-Peer Networks A Comparison

The goal of this paper is to make the similarities and differences of Peer-to-Peer (P2P) and Mobile Ad Hoc (MANET) networks clear. Thus we want to show the synergetic potential hidden in these two decentralized and self organizing networks. As well as both networks are established on a different physical layer, both networks hold similarities concerning their routing and network management principles. The reason therefore is, that both of them have to solve a similar goal, namely to provide networking functionalities in a completely unmanaged and decentralized environment. One of the most interesting tasks in these networks is thus how queries are guided through the network. Therefore we concentrate in this work on the different routing algorithms employed in Peer-to-Peer and mobile ad hoc networks. Finally, the similarities of both networks can be used, to bring up the synergetic effects of looking at both networks at the same time.

Wireless live streaming video of surgical operations: an evaluation of communication quality

We evaluated a mobile video system for surgical teleconsultation. A video streaming server in the operating room transmitted video and audio to a hand-held computer (personal digital assistant [PDA]) over a wireless local area network. Two groups of 20 surgeons (each with 12 qualified surgeons and eight surgeons between the 2nd and the 4th year of training) participated in the tests. For voice transmission, correct understanding of numbers was achieved in 100% of the cases (n = 1000) and 98% of medical terms (n = 400). The quality of the video displayed on the PDA was assessed by the recognition of different operating room scenarios. Only 62% (SD 17) of the structures were identified clearly on the hand-held device (n = 400). The accuracy improved to 78% (SD 15) (n = 400) if the same scenario was observed on a larger (50 cm) video screen (p < 0.001). Accuracy was significantly better if audio conversation was possible. The quality evaluation by the consultants showed that the PDA display size and quality were sufficient for clinical use.