Two publications were selected in 2010 for the ITS Outstanding Publication Award.
- Stephen Voran and Andrew Catellier for the work presented in their paper, “Multiple-Description Speech Coding Using Speech-Polarity Decomposition,” published in the Proceedings of the IEEE Global Communications Conference (GLOBECOM) in December 2010.
The paper presented a new multiple-description speech coding extension to the international standard for pulse code modulation speech coding (ITU-T Rec. G.711), a very widely used method for compressing speech for transport over networks. The extension uses speech polarity decomposition to spread a transmitted speech signal across two channels thus increasing signal robustness to packet losses. Signal robustness is important because packet losses cannot be predicted or controlled, only compensated for.
Both the algorithm and the paper presentation itself were judged impressive by several technical reviewers during internal peer review and the paper was nominated for and received the calendar year 2010 ITS Outstanding Publications Award in the category of outside journal articles. The award is determined by a distinct peer review panel that includes at least one outside member. ITS is not aware of any other viable multiple-description coding extension that simultaneously meets the opposing goals of no quality penalty and no rate penalty. The work done by these engineers presents a proof-of-concept for multiple description codecs that preserve quality with little or no rate increase-an important prerequisite to expanding reliable voice transmission over crowded networks.
- Robert T. Johnk, John D. Ewan, Paul M. McKenna, Ronald L. Carey, and Nicholas DeMinco for the work presented in NTIA Technical Report TR-10-471, “Time-domain propagation measurements of the NASA Space-Power Facility,” published in September 2010
The measurement and analysis effort documented in this paper was commissioned by NASA via a reimbursable other agency agreement with ITS to assess the feasibility of using NASA's Glenn Space-Power Facility in Sandusky, Ohio, for electromagnetic environmental effects (E3) testing. The digital signal processing techniques that were employed by the research team represent a novel approach to understanding the reverberation characteristics of a large conductive chamber of this nature. This was the first time that time-domain measurements were used to investigate reverberation characteristics of the facility, and insights gained through this effort can be extended to other types of reverberation chambers. This measurement effort not only provided valuable insights to the sponsor but also helped validate a reverberant chamber model which can be applied to other facilities of this nature. The report documenting this work was nominated for and received the calendar year 2010 ITS Outstanding Publications Award in the category of NTIA reports. The award is determined by a distinct peer review panel that includes at least one outside member.
The research team performed an extensive set of measurements and conducted joint time and frequency analysis to characterize the facility. They demonstrated the validity of their measurement data via intercomparison with measurements collected by a NIST research team that showed close agreement between the data sets. They also compared the measurement data to predictions derived from a two-dimensional finite difference time domain (FDTD) model of the chamber. Comparisons between measured and predicted power decay times showed also close agreement. The results of the measurement effort suggest that, from a radiofrequency standpoint, the chamber would be a good candidate for use as a reverberation chamber. Use of an existing facility for E3 testing would result in considerable program cost savings for NASA.