The relatio nship between delayed a uditory feedback and articula tor movement was studied using ... more The relatio nship between delayed a uditory feedback and articula tor movement was studied using strain gauge a nd cinefluorographic techniques. Zero, 100, and 200ms delay conditions were used. Articulator behav ior associated with the " typical" DAF effects (slowed speech a nd repetitive ges tures) was studied in detail. The results reveal consistent relationships betwee n DAF offset across delay conditions. That is, the common strategy is to "a llow" the DAF to go off before beginning the subsequent CV gesture. The res ults a lso reveal a consistent relationship between onset of delayed a uditory feedback , phase of articulator movement a nd type of speech brea kd own (prolongation o r repetition). Repetitive breakdowns consistentl y occur when the delayed auditory feedback is on at the onset of mo vement for the subsequent gesture. These res ults indicate that the 200 ms delay condition is more perturbing beca use the delayed signal is more likely to be on during the movement onset for the next gest ure than is the I 00 ms delayed signal. The results are consistent with the perturbing effects of stimula tion in other movement systems (gait, mastica tion , limb movement) .
The purpose of this study was to determine the impact of a digital noise reduction (DNR) scheme i... more The purpose of this study was to determine the impact of a digital noise reduction (DNR) scheme implemented in a current commercial hearing aid. In a double-blinded design, three conditions of onset time (4, 8, 16 seconds) were randomly assigned to the 25 subjects, plus one condition wherein the noise-reduction feature was disengaged. Subsequently, a fifth trial/condition, wherein the subject had access to three memories in which the different onsets were programmed, was carried out. For each of the five conditions, the subjects had an at-home trial, prior to obtaining self-report measures. Laboratory measures of speech perception showed no effect of the DNR, with or without the provision of visual cues. Laboratory-based ratings of ease of listening showed DNR-on (all onset times) to be rated significantly better than DNR-off; for ratings of listening comfort, the 4-second onset time was rated significantly lower (poorer) than the 8-second onset or the DNR-off condition; for ratings of sound quality, DNR-on or -off had no differential effect. Self-report measures indicated significantly higher aversiveness in the DNR-off condition compared to the pre-test scores.
We studied three subjects who reported the apparent "disappearance" of stationa... more We studied three subjects who reported the apparent "disappearance" of stationary objects from direct view. They had simultanagnosia caused by CT-verified bilateral superior occipital lobe lesions. They had no abnormalities of visual acuity or fields to explain their defect. EOG with computer analysis showed intact motility and scanning. Most important, the subjects reported intermittent disappearance of a light target during EOG-verified fixation--ie, they were looking but not seeing. Results indicate that attention mechanisms that permit sustained awareness of visual targets depend on the superior visual association cortices and are relatively separate from mechanisms that shift gaze and drive visual search.
Perspectives on Augmentative and Alternative Communication, Jun 1, 2013
The objective of the symposium was to bring together the scientists working in industries, resear... more The objective of the symposium was to bring together the scientists working in industries, research organizations and academia, who were engaged in the global environmental problems and in the areas of nuclear energy. It was intended to provide a forum for cross-fertilization among the participants and for open discussions in pursuit of the common solutions to the problem, in particular environmental problems associated with water and atmosphere and those with the utilization of the nuclear energy. Discussions will be directed toward the analysis of environmental impact and construction of the nuclear energy systems that provide the solution. We would like to thank the members of the organizing committee and the program committee for their advice and contributions. We are indebted to all the authors for submitting their original papers. Special thanks go to Mses. Etsuko Koizumi and Michiko Yugami whose efforts above and beyond the call of duty that were indispensable to the accomplishment of the tasks of the organizing and program committees. Finally, I would like to express my gratitude to the members of the secretariat:
Children's discourse competence is assessed in three story tasks designed to evaluate the... more Children's discourse competence is assessed in three story tasks designed to evaluate the inferential processes necessary to construct sequences of events to confirm a given consequence and those processes necessary to infer consequences from premise information. The use of pictured story elements minimized memory and expository skill factors and allowed us to study the discourse competence of children as young
A phoneme-monitoring task was employed to test the effects of clausal structure and lexical ambig... more A phoneme-monitoring task was employed to test the effects of clausal structure and lexical ambiguity on sentence processing. Results supported the hypothesis that the clause serves as a psychologically real unit of sentence processing, with the semantic interpretation of each clause being assigned at the clause boundary. The frequency of the ambiguous or control word preceding the critical item in the phoneme-monitoring task was also found to affect the results obtained, with higher frequency words leading to longer mean reaction times.
Journal of the Acoustical Society of America, Oct 1, 1999
Like all such measurements, the source data for speaker recognition is subject to errors in measu... more Like all such measurements, the source data for speaker recognition is subject to errors in measurement due to transducer, channel, and quantization effects. When training and test equipment are known, one may calibrate the hardware and introduce a noise compensation procedure into the recognition process. In many applications, it is highly desirable for speaker recognition tasks to function with a wide variety of unknown equipment, making calibration impractical. A study is presented with the a priori assumption that for each feature vector o↘̂ observed with measurement noise, an error compensated vector o↘̂ lies within some uniformly distributed interval ±ε of the observed vector. A statistic derived from the observation set is computed and used to estimate an empirical interval in the neighborhood of each observation. An approximation to integration over the interval is carried out and is used in place of the density measurement at o↘. Tests using a 15-component cepstral feature vector derived from telephone quality speech (King corpus, San Diego speakers, sessions 1–5) have shown reductions of error rate on the order of 15% as compared to a baseline system. Techniques to reduce the algorithmic cost of the integration will also be discussed.
The effects of smoking marijuana on cognition and brain function were assessed with PET using H 2... more The effects of smoking marijuana on cognition and brain function were assessed with PET using H 2 15 O. Regional cerebral blood¯ow (rCBF) was measured in ®ve recreational users before and after smoking a marijuana cigarette, as they repeatedly performed an auditory attention task. Blood¯ow increased following smoking in a number of paralimbic brain regions (e.g. orbital frontal lobes, insula, temporal poles) and in anterior cingulate and cerebellum. Large reductions in rCBF were observed in temporal lobe regions that are sensitive to auditory attention effects. Brain regions showing increased rCBF may mediate the intoxicating and mood-related effects of smoking marijuana, whereas reduction of task-related rCBF in temporal lobe cortices may account for the impaired cognitive functions associated with acute intoxication. NeuroReport
It is well known that simple amplification cannot help many hearing-impaired listeners. As a cons... more It is well known that simple amplification cannot help many hearing-impaired listeners. As a consequence of this, numerous signal enhancement algorithms have been proposed for digital hearing aids. Many of these algorithms are only effective in certain environments. The ability to quickly and correctly detect elements of the auditory scene can permit the selection/parameterization of enhancement algorithms from a library
IEEE Transactions on Speech and Audio Processing, Jul 1, 2002
Recent work by Merhav and Lee as well as others has emphasized that the conditions required to ma... more Recent work by Merhav and Lee as well as others has emphasized that the conditions required to make the maximum a posteriori (MAP) decision rule an optimal decision rule for speech recognition do not hold and have proposed techniques based upon the adjustment of model parameters to improve speech recognition. In this article, we consider the problem of text-independent speaker recognition, and present a new model called the integral decode. The integral decode, like previous work in this area, attempts to compensate for the lack of conditions necessary to ensure optimality of the MAP decision rule in environments with corrupted observations and imperfect models. The integral decode is a smoothing operation in the feature space domain. A region of uncertainty is established about each noisy observation and an approximation of the integral is computed. The MAP decision rule is then applied to the smoothed likelihood estimates. In all tested conditions, the integral decode performs as well as or better than equivalent HMMs without integral decode.
The relatio nship between delayed a uditory feedback and articula tor movement was studied using ... more The relatio nship between delayed a uditory feedback and articula tor movement was studied using strain gauge a nd cinefluorographic techniques. Zero, 100, and 200ms delay conditions were used. Articulator behav ior associated with the " typical" DAF effects (slowed speech a nd repetitive ges tures) was studied in detail. The results reveal consistent relationships betwee n DAF offset across delay conditions. That is, the common strategy is to "a llow" the DAF to go off before beginning the subsequent CV gesture. The res ults a lso reveal a consistent relationship between onset of delayed a uditory feedback , phase of articulator movement a nd type of speech brea kd own (prolongation o r repetition). Repetitive breakdowns consistentl y occur when the delayed auditory feedback is on at the onset of mo vement for the subsequent gesture. These res ults indicate that the 200 ms delay condition is more perturbing beca use the delayed signal is more likely to be on during the movement onset for the next gest ure than is the I 00 ms delayed signal. The results are consistent with the perturbing effects of stimula tion in other movement systems (gait, mastica tion , limb movement) .
The purpose of this study was to determine the impact of a digital noise reduction (DNR) scheme i... more The purpose of this study was to determine the impact of a digital noise reduction (DNR) scheme implemented in a current commercial hearing aid. In a double-blinded design, three conditions of onset time (4, 8, 16 seconds) were randomly assigned to the 25 subjects, plus one condition wherein the noise-reduction feature was disengaged. Subsequently, a fifth trial/condition, wherein the subject had access to three memories in which the different onsets were programmed, was carried out. For each of the five conditions, the subjects had an at-home trial, prior to obtaining self-report measures. Laboratory measures of speech perception showed no effect of the DNR, with or without the provision of visual cues. Laboratory-based ratings of ease of listening showed DNR-on (all onset times) to be rated significantly better than DNR-off; for ratings of listening comfort, the 4-second onset time was rated significantly lower (poorer) than the 8-second onset or the DNR-off condition; for ratings of sound quality, DNR-on or -off had no differential effect. Self-report measures indicated significantly higher aversiveness in the DNR-off condition compared to the pre-test scores.
We studied three subjects who reported the apparent "disappearance" of stationa... more We studied three subjects who reported the apparent "disappearance" of stationary objects from direct view. They had simultanagnosia caused by CT-verified bilateral superior occipital lobe lesions. They had no abnormalities of visual acuity or fields to explain their defect. EOG with computer analysis showed intact motility and scanning. Most important, the subjects reported intermittent disappearance of a light target during EOG-verified fixation--ie, they were looking but not seeing. Results indicate that attention mechanisms that permit sustained awareness of visual targets depend on the superior visual association cortices and are relatively separate from mechanisms that shift gaze and drive visual search.
Perspectives on Augmentative and Alternative Communication, Jun 1, 2013
The objective of the symposium was to bring together the scientists working in industries, resear... more The objective of the symposium was to bring together the scientists working in industries, research organizations and academia, who were engaged in the global environmental problems and in the areas of nuclear energy. It was intended to provide a forum for cross-fertilization among the participants and for open discussions in pursuit of the common solutions to the problem, in particular environmental problems associated with water and atmosphere and those with the utilization of the nuclear energy. Discussions will be directed toward the analysis of environmental impact and construction of the nuclear energy systems that provide the solution. We would like to thank the members of the organizing committee and the program committee for their advice and contributions. We are indebted to all the authors for submitting their original papers. Special thanks go to Mses. Etsuko Koizumi and Michiko Yugami whose efforts above and beyond the call of duty that were indispensable to the accomplishment of the tasks of the organizing and program committees. Finally, I would like to express my gratitude to the members of the secretariat:
Children's discourse competence is assessed in three story tasks designed to evaluate the... more Children's discourse competence is assessed in three story tasks designed to evaluate the inferential processes necessary to construct sequences of events to confirm a given consequence and those processes necessary to infer consequences from premise information. The use of pictured story elements minimized memory and expository skill factors and allowed us to study the discourse competence of children as young
A phoneme-monitoring task was employed to test the effects of clausal structure and lexical ambig... more A phoneme-monitoring task was employed to test the effects of clausal structure and lexical ambiguity on sentence processing. Results supported the hypothesis that the clause serves as a psychologically real unit of sentence processing, with the semantic interpretation of each clause being assigned at the clause boundary. The frequency of the ambiguous or control word preceding the critical item in the phoneme-monitoring task was also found to affect the results obtained, with higher frequency words leading to longer mean reaction times.
Journal of the Acoustical Society of America, Oct 1, 1999
Like all such measurements, the source data for speaker recognition is subject to errors in measu... more Like all such measurements, the source data for speaker recognition is subject to errors in measurement due to transducer, channel, and quantization effects. When training and test equipment are known, one may calibrate the hardware and introduce a noise compensation procedure into the recognition process. In many applications, it is highly desirable for speaker recognition tasks to function with a wide variety of unknown equipment, making calibration impractical. A study is presented with the a priori assumption that for each feature vector o↘̂ observed with measurement noise, an error compensated vector o↘̂ lies within some uniformly distributed interval ±ε of the observed vector. A statistic derived from the observation set is computed and used to estimate an empirical interval in the neighborhood of each observation. An approximation to integration over the interval is carried out and is used in place of the density measurement at o↘. Tests using a 15-component cepstral feature vector derived from telephone quality speech (King corpus, San Diego speakers, sessions 1–5) have shown reductions of error rate on the order of 15% as compared to a baseline system. Techniques to reduce the algorithmic cost of the integration will also be discussed.
The effects of smoking marijuana on cognition and brain function were assessed with PET using H 2... more The effects of smoking marijuana on cognition and brain function were assessed with PET using H 2 15 O. Regional cerebral blood¯ow (rCBF) was measured in ®ve recreational users before and after smoking a marijuana cigarette, as they repeatedly performed an auditory attention task. Blood¯ow increased following smoking in a number of paralimbic brain regions (e.g. orbital frontal lobes, insula, temporal poles) and in anterior cingulate and cerebellum. Large reductions in rCBF were observed in temporal lobe regions that are sensitive to auditory attention effects. Brain regions showing increased rCBF may mediate the intoxicating and mood-related effects of smoking marijuana, whereas reduction of task-related rCBF in temporal lobe cortices may account for the impaired cognitive functions associated with acute intoxication. NeuroReport
It is well known that simple amplification cannot help many hearing-impaired listeners. As a cons... more It is well known that simple amplification cannot help many hearing-impaired listeners. As a consequence of this, numerous signal enhancement algorithms have been proposed for digital hearing aids. Many of these algorithms are only effective in certain environments. The ability to quickly and correctly detect elements of the auditory scene can permit the selection/parameterization of enhancement algorithms from a library
IEEE Transactions on Speech and Audio Processing, Jul 1, 2002
Recent work by Merhav and Lee as well as others has emphasized that the conditions required to ma... more Recent work by Merhav and Lee as well as others has emphasized that the conditions required to make the maximum a posteriori (MAP) decision rule an optimal decision rule for speech recognition do not hold and have proposed techniques based upon the adjustment of model parameters to improve speech recognition. In this article, we consider the problem of text-independent speaker recognition, and present a new model called the integral decode. The integral decode, like previous work in this area, attempts to compensate for the lack of conditions necessary to ensure optimality of the MAP decision rule in environments with corrupted observations and imperfect models. The integral decode is a smoothing operation in the feature space domain. A region of uncertainty is established about each noisy observation and an approximation of the integral is computed. The MAP decision rule is then applied to the smoothed likelihood estimates. In all tested conditions, the integral decode performs as well as or better than equivalent HMMs without integral decode.
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Papers by Richard Hurtig