Richard Stern | The George Washington University (original) (raw)

Papers by Richard Stern

Interspeech, 2006

This paper describes the structure and performance of a new signal processing scheme, motivated b... more This paper describes the structure and performance of a new signal processing scheme, motivated by the physiology of the peripheral auditory system, that improves speech recognition accuracy in the presence of broadband noise. An important attribute of the peripheral processing is a novel mechanism to represent the cycle-by-cycle synchrony in the response of low-frequency auditory-nerve fibers, in addition to the more conventional processing based on mean rate of response. It is shown that the use of the physiologically-motivated peripheral processing improves recognition accuracy in the presence of both broadband and transient noise, and that the use of the synchrony mechanism provides further improvement beyond that which is provided by the mean rate mechanism.

Fordham Intellectual Property Media and Entertainment Law Journal, 1999

Speech Communication, 2001

We present a method to reduce the degradation in recognition accuracy introduced by full-rate GSM... more We present a method to reduce the degradation in recognition accuracy introduced by full-rate GSM RPE-LTP coding by combining sets of acoustic models trained under dierent distortion conditions. During recognition, the a posteriori probabilities of an utterance are calculated as a weighted sum of the posteriors corresponding to the individual models. The phonemes used by the systemÕs word pronunciations are grouped into classes according to amount of distortion they undergo in coding. The acoustic model used in the decoding process is a weighted combination of models derived from clean speech and models derived from speech that had been degraded by GSM coding (the source models), with the relative combination of the two sources depending on the extent to which each class of phonemes is degraded by the coding process. To determine the distortion class membership, and hence the weights, we measure the spectral distortion introduced to the quantized long-term residual by the RPE-LTP codec. We discuss how this distortion varies according to phonetic class. The method described reduces the degradation in recognition accuracy introduced by GSM coding of sentences in the TIMIT database by more than 70% relative to the baseline accuracy obtained in matched training and testing conditions with respect to a system using the source acoustic models, and up to 60% relative to the best baseline systems regardless of the number of Gaussians. Ó (J.M. Huerta). 0167-6393/01/$ -see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 -6 3 9 3 ( 0 0 ) 0 0 0 5 5 -8

IEEE Computer Graphics and Applications, 2000

Canadian Journal of Earth Sciences, 1999

ABSTRACT The Flin Flon Belt (Trans-Hudson Orogen, Manitoba and Saskatchewan) is the largest Paleo... more ABSTRACT The Flin Flon Belt (Trans-Hudson Orogen, Manitoba and Saskatchewan) is the largest Paleoproterozoic volcanic-hosted massive sulphide (VMS) district in the world, with 118.7 million tonnes (Mt) of Zn-Cu-(Au-Ag) sulphide ore in 25 past or presently producing mines and 64.3 Mt in subeconomic deposits. The orebodies are restricted to isotopically juvenile volcanic-arc sequences, dated at 1.903-1.881 Ga at Flin Flon. Sequences of ca. 1.904-1.901 Ga back-arc and ocean-plateau basalts and related plutonic rocks, structurally juxtaposed with the arc assemblages at 1.880-1.870 Ga, are not known to contain economic base metal deposits. The juvenile arc tectono-stratigraphic assemblages are generally marked by older and stratigraphically lower tholeiitic submarine volcanic packages (ca. 1.903-1.886 Ga) that are observed or interpreted to be overlain by extensive and lithologically varied sequences of calc-alkaline and alkaline (shoshonitic) arc rocks and arc rift deposits (ca. 1.888-1.881 Ga). VMS deposits occur in both the tholeiitic and calc-alkaline arc sequences, but the 62 Mt Flin Flon deposit occurs in a 1.903 Ga tholeiitic primitive arc package. It can be demonstrated that for the Flin Flon - Callinan - Triple 7, Cuprus, and White Lake VMS deposits, whose stratigraphic context is preserved, deposition of the massive sulphides was temporally associated with inferred arc rifting processes. Critical observations for arc rifting include evidence for extensional faulting, erosion, and development of unconformities; extrusion of MORB-like basalts and associated rhyolites; and development of depositional basins with thick sequences of shoshonitic turbidites. As has been proposed for other major VMS camps (e.g., Kuroko, Kidd Creek, Bathurst), arc rifting can generate the loci of sustained high heat flow and fluid pathways required for the development of long-lived hydrothermal convection systems.

International Orthopaedics, 2012

Purpose Long-term studies evaluating risk factors for development of ankle osteoarthritis (OA) fo... more Purpose Long-term studies evaluating risk factors for development of ankle osteoarthritis (OA) following malleolar fractures are sparse. Methods We conducted a retrospective cohort study including consecutive patients treated by open reduction and internal fixation for malleolar fracture between January 1988 and December 1997. Perioperative information was obtained retrospectively. Patients were evaluated clinically and radiographically 12-22 years postoperatively. Radiographic ankle OA was determined on standardised radiographs using the Kellgren and Lawrence scale (grade 3-40 advanced OA). Uni-and multivariate regression analyses were performed to determine risk factors for OA. Results During the inclusion period, 373 fractures (372 patients; 9% Weber A, 58% Weber B, 33% Weber C) were operated upon. The mean age at operation was 42.9 years. There were 102 patients seen at follow-up (mean follow-up 17.9 years). Those not available did not differ in demographics and fracture type from those seen. Advanced radiographic OA was present in 37 patients (36.3%). Significant risk factors were: Weber C fracture, associated medial malleolar fracture, fracture-dislocation, increasing body mass index, age 30 years or more and length of time since surgery.

International Journal of Production Research, 1983

In this paper we present new algorithms for processing a set of orders in automated warehousing s... more In this paper we present new algorithms for processing a set of orders in automated warehousing systems. The proposed algorithms will process the orders by grouping some of them according to criteria developed by the authors. The travelling salesman algorithm is ...