2009 Recipients

CQR 2009, May 10-12, Naples, Florida

“Predicting the Quality of Voice over IP Networks”

Sanghyun CHI and Baxter F. WOMACK

Abstract – Clients have still hesitated to switch conventional phone service with voice over IP networks (VoIP) service because VoIP service providers are not successful in providing consistent quality during a call. The uncertainness of IP networks, the legacy of packet-switched networks, makes it hard to predict service quality and demands real-time based monitoring. In this paper, we propose a prediction voice quality metric to monitor the quality of VoIP service. Based on a learning machine, the proposed metric nonlinearly weighs network parameters to estimate speech quality. Finally, performance analysis shows that the proposed metric achieves the high prediction accuracy.


“Proof of optimal algorithm for maximum-bandwidth ALM tree construction”

Takamichi KIKKAWA, Takamichi MIYATA and Katsunori YAMAOKA

Abstract – We construct an ALM tree that achieves the maximum bandwidth by using underlay topology information. Since this problem was previously shown to be NP-hard, no polynomial time algorithms for maximum-bandwidth ALM tree construction exist. In our work, we assume that the underlay network has a tree network topology, and we show a polynomial-time algorithm that constructs a maximum-bandwidth ALM tree on such a tree network topology. We propose an ALM tree construction algorithm that achieves bandwidth b and apply this algorithm with various bandwidth values b. We show that it can make a maximum-bandwidth ALM tree in polynomial time.