This letter presents an efficient method for the maritime Loran-C additional secondary factor (ASF) correction based on equivalent ground conductivity inversion. Using the proposed method, the accuracy of Loran-C system on maritime positioning, navigation, and timing (PNT) can be improved significantly with a limited number of surveys. Comparison with measured ASF results shows a root-mean-square error (RMSE) of less than 100 ns in most areas.

Experiments were performed to investigate perceptual contributions of static and dynamic features of vocal tract characteristics to talker individuality. An ARX (Auto-regressive with exogenous input) speech production model was used to extract separately voice source and vocal tract parameters from a Japanese sentence, /aoiueoie/ ("Say blue top" in English) uttered by three males. The Discrete Cosine Transform (DCT) was applied to resolve formant trajectories of the speech signal into static and dynamic components. The perceptual contributions were quantitatively studied by systematically replacing the corresponding formant components of the sentences between the three talkers. Results of the experiments show that the static (average) feature of the vocal tract is a primary cue to talker individuality.