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Sample records for delayed auditory feedback

  1. Feedback delays eliminate auditory-motor learning in speech production.

    Science.gov (United States)

    Max, Ludo; Maffett, Derek G

    2015-03-30

    Neurologically healthy individuals use sensory feedback to alter future movements by updating internal models of the effector system and environment. For example, when visual feedback about limb movements or auditory feedback about speech movements is experimentally perturbed, the planning of subsequent movements is adjusted - i.e., sensorimotor adaptation occurs. A separate line of studies has demonstrated that experimentally delaying the sensory consequences of limb movements causes the sensory input to be attributed to external sources rather than to one's own actions. Yet similar feedback delays have remarkably little effect on visuo-motor adaptation (although the rate of learning varies, the amount of adaptation is only moderately affected with delays of 100-200ms, and adaptation still occurs even with a delay as long as 5000ms). Thus, limb motor learning remains largely intact even in conditions where error assignment favors external factors. Here, we show a fundamentally different result for sensorimotor control of speech articulation: auditory-motor adaptation to formant-shifted feedback is completely eliminated with delays of 100ms or more. Thus, for speech motor learning, real-time auditory feedback is critical. This novel finding informs theoretical models of human motor control in general and speech motor control in particular, and it has direct implications for the application of motor learning principles in the habilitation and rehabilitation of individuals with various sensorimotor speech disorders. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Individual Variability in Delayed Auditory Feedback Effects on Speech Fluency and Rate in Normally Fluent Adults

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    Chon, HeeCheong; Kraft, Shelly Jo; Zhang, Jingfei; Loucks, Torrey; Ambrose, Nicoline G.

    2013-01-01

    Purpose: Delayed auditory feedback (DAF) is known to induce stuttering-like disfluencies (SLDs) and cause speech rate reductions in normally fluent adults, but the reason for speech disruptions is not fully known, and individual variation has not been well characterized. Studying individual variation in susceptibility to DAF may identify factors…

  3. Adaptation to delayed auditory feedback induces the temporal recalibration effect in both speech perception and production.

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    Yamamoto, Kosuke; Kawabata, Hideaki

    2014-12-01

    We ordinarily speak fluently, even though our perceptions of our own voices are disrupted by various environmental acoustic properties. The underlying mechanism of speech is supposed to monitor the temporal relationship between speech production and the perception of auditory feedback, as suggested by a reduction in speech fluency when the speaker is exposed to delayed auditory feedback (DAF). While many studies have reported that DAF influences speech motor processing, its relationship to the temporal tuning effect on multimodal integration, or temporal recalibration, remains unclear. We investigated whether the temporal aspects of both speech perception and production change due to adaptation to the delay between the motor sensation and the auditory feedback. This is a well-used method of inducing temporal recalibration. Participants continually read texts with specific DAF times in order to adapt to the delay. Then, they judged the simultaneity between the motor sensation and the vocal feedback. We measured the rates of speech with which participants read the texts in both the exposure and re-exposure phases. We found that exposure to DAF changed both the rate of speech and the simultaneity judgment, that is, participants' speech gained fluency. Although we also found that a delay of 200 ms appeared to be most effective in decreasing the rates of speech and shifting the distribution on the simultaneity judgment, there was no correlation between these measurements. These findings suggest that both speech motor production and multimodal perception are adaptive to temporal lag but are processed in distinct ways.

  4. Temporal recalibration in vocalization induced by adaptation of delayed auditory feedback.

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    Kosuke Yamamoto

    Full Text Available BACKGROUND: We ordinarily perceive our voice sound as occurring simultaneously with vocal production, but the sense of simultaneity in vocalization can be easily interrupted by delayed auditory feedback (DAF. DAF causes normal people to have difficulty speaking fluently but helps people with stuttering to improve speech fluency. However, the underlying temporal mechanism for integrating the motor production of voice and the auditory perception of vocal sound remains unclear. In this study, we investigated the temporal tuning mechanism integrating vocal sensory and voice sounds under DAF with an adaptation technique. METHODS AND FINDINGS: Participants produced a single voice sound repeatedly with specific delay times of DAF (0, 66, 133 ms during three minutes to induce 'Lag Adaptation'. They then judged the simultaneity between motor sensation and vocal sound given feedback. We found that lag adaptation induced a shift in simultaneity responses toward the adapted auditory delays. This indicates that the temporal tuning mechanism in vocalization can be temporally recalibrated after prolonged exposure to delayed vocal sounds. Furthermore, we found that the temporal recalibration in vocalization can be affected by averaging delay times in the adaptation phase. CONCLUSIONS: These findings suggest vocalization is finely tuned by the temporal recalibration mechanism, which acutely monitors the integration of temporal delays between motor sensation and vocal sound.

  5. Adaptation to Delayed Speech Feedback Induces Temporal Recalibration between Vocal Sensory and Auditory Modalities

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    Kosuke Yamamoto

    2011-10-01

    Full Text Available We ordinarily perceive our voice sound as occurring simultaneously with vocal production, but the sense of simultaneity in vocalization can be easily interrupted by delayed auditory feedback (DAF. DAF causes normal people to have difficulty speaking fluently but helps people with stuttering to improve speech fluency. However, the underlying temporal mechanism for integrating the motor production of voice and the auditory perception of vocal sound remains unclear. In this study, we investigated the temporal tuning mechanism integrating vocal sensory and voice sounds under DAF with an adaptation technique. Participants read some sentences with specific delay times of DAF (0, 30, 75, 120 ms during three minutes to induce ‘Lag Adaptation’. After the adaptation, they then judged the simultaneity between motor sensation and vocal sound given feedback in producing simple voice but not speech. We found that speech production with lag adaptation induced a shift in simultaneity responses toward the adapted auditory delays. This indicates that the temporal tuning mechanism in vocalization can be temporally recalibrated after prolonged exposure to delayed vocal sounds. These findings suggest vocalization is finely tuned by the temporal recalibration mechanism, which acutely monitors the integration of temporal delays between motor sensation and vocal sound.

  6. Auditory Masking Effects on Speech Fluency in Apraxia of Speech and Aphasia: Comparison to Altered Auditory Feedback

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    Jacks, Adam; Haley, Katarina L.

    2015-01-01

    Purpose: To study the effects of masked auditory feedback (MAF) on speech fluency in adults with aphasia and/or apraxia of speech (APH/AOS). We hypothesized that adults with AOS would increase speech fluency when speaking with noise. Altered auditory feedback (AAF; i.e., delayed/frequency-shifted feedback) was included as a control condition not…

  7. Hear You Later Alligator: How delayed auditory feedback affects non-musically trained people’s strumming

    DEFF Research Database (Denmark)

    Larsen, Jeppe Veirum; Knoche, Hendrik

    2017-01-01

    of an actuated guitar to a metronome at 60bpm and 120bpm. The long DAF matched a subdivision of the overall tempo. We compared their performance using two different input devices with feedback before or on activation. While 250ms DAF hardly affected musically trained participants, non-musically trained...

  8. Stuttering Inhibition via Altered Auditory Feedback during Scripted Telephone Conversations

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    Hudock, Daniel; Kalinowski, Joseph

    2014-01-01

    Background: Overt stuttering is inhibited by approximately 80% when people who stutter read aloud as they hear an altered form of their speech feedback to them. However, levels of stuttering inhibition vary from 60% to 100% depending on speaking situation and signal presentation. For example, binaural presentations of delayed auditory feedback…

  9. Stuttering Inhibition via Altered Auditory Feedback during Scripted Telephone Conversations

    Science.gov (United States)

    Hudock, Daniel; Kalinowski, Joseph

    2014-01-01

    Background: Overt stuttering is inhibited by approximately 80% when people who stutter read aloud as they hear an altered form of their speech feedback to them. However, levels of stuttering inhibition vary from 60% to 100% depending on speaking situation and signal presentation. For example, binaural presentations of delayed auditory feedback…

  10. Altered Sensory Feedbacks in Pianist's Dystonia: the altered auditory feedback paradigm and the glove effect

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    Felicia Pei-Hsin Cheng

    2013-12-01

    Full Text Available Background: This study investigates the effect of altered auditory feedback (AAF in musician's dystonia (MD and discusses whether altered auditory feedback can be considered as a sensory trick in MD. Furthermore, the effect of AAF is compared with altered tactile feedback, which can serve as a sensory trick in several other forms of focal dystonia. Methods: The method is based on scale analysis (Jabusch et al. 2004. Experiment 1 employs synchronization paradigm: 12 MD patients and 25 healthy pianists had to repeatedly play C-major scales in synchrony with a metronome on a MIDI-piano with 3 auditory feedback conditions: 1. normal feedback; 2. no feedback; 3. constant delayed feedback. Experiment 2 employs synchronization-continuation paradigm: 12 MD patients and 12 healthy pianists had to repeatedly play C-major scales in two phases: first in synchrony with a metronome, secondly continue the established tempo without the metronome. There are 4 experimental conditions, among them 3 are the same altered auditory feedback as in Experiment 1 and 1 is related to altered tactile sensory input. The coefficient of variation of inter-onset intervals of the key depressions was calculated to evaluate fine motor control. Results: In both experiments, the healthy controls and the patients behaved very similarly. There is no difference in the regularity of playing between the two groups under any condition, and neither did AAF nor did altered tactile feedback have a beneficial effect on patients’ fine motor control. Conclusions: The results of the two experiments suggest that in the context of our experimental designs, AAF and altered tactile feedback play a minor role in motor coordination in patients with musicians' dystonia. We propose that altered auditory and tactile feedback do not serve as effective sensory tricks and may not temporarily reduce the symptoms of patients suffering from MD in this experimental context.

  11. Duration reproduction with sensory feedback delay: Differential involvement of perception and action time

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    Stephanie eGanzenmüller

    2012-10-01

    Full Text Available Previous research has shown that voluntary action can attract subsequent, delayed feedback events towards the action, and adaptation to the sensorimotor delay can even reverse motor-sensory temporal-order judgments. However, whether and how sensorimotor delay affects duration reproduction is still unclear. To investigate this, we injected an onset- or offset-delay to the sensory feedback signal from a duration reproduction task. We compared duration reproductions within (visual, auditory modality and across audiovisual modalities with feedback signal onset- and offset-delay manipulations. We found that the reproduced duration was lengthened in both visual and auditory feedback signal onset-delay conditions. The lengthening effect was evident immediately, on the first trial with the onset delay. However, when the onset of the feedback signal was prior to the action, the lengthening effect was diminished. In contrast, a shortening effect was found with feedback signal offset-delay, though the effect was weaker and manifested only in the auditory offset-delay condition. These findings indicate that participants tend to mix the onset of action and the feedback signal more when the feedback is delayed, and they heavily rely on motor-stop signals for the duration reproduction. Furthermore, auditory duration was overestimated compared to visual duration in crossmodal feedback conditions, and the overestimation of auditory duration (or the underestimation of visual duration was independent of the delay manipulation.

  12. An Experimental Investigation of the Effect of Altered Auditory Feedback on the Conversational Speech of Adults Who Stutter

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    Lincoln, Michelle; Packman, Ann; Onslow, Mark; Jones, Mark

    2010-01-01

    Purpose: To investigate the impact on percentage of syllables stuttered of various durations of delayed auditory feedback (DAF), levels of frequency-altered feedback (FAF), and masking auditory feedback (MAF) during conversational speech. Method: Eleven adults who stuttered produced 10-min conversational speech samples during a control condition…

  13. Neural mechanisms underlying auditory feedback control of speech.

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    Tourville, Jason A; Reilly, Kevin J; Guenther, Frank H

    2008-02-01

    The neural substrates underlying auditory feedback control of speech were investigated using a combination of functional magnetic resonance imaging (fMRI) and computational modeling. Neural responses were measured while subjects spoke monosyllabic words under two conditions: (i) normal auditory feedback of their speech and (ii) auditory feedback in which the first formant frequency of their speech was unexpectedly shifted in real time. Acoustic measurements showed compensation to the shift within approximately 136 ms of onset. Neuroimaging revealed increased activity in bilateral superior temporal cortex during shifted feedback, indicative of neurons coding mismatches between expected and actual auditory signals, as well as right prefrontal and Rolandic cortical activity. Structural equation modeling revealed increased influence of bilateral auditory cortical areas on right frontal areas during shifted speech, indicating that projections from auditory error cells in posterior superior temporal cortex to motor correction cells in right frontal cortex mediate auditory feedback control of speech.

  14. Rapid change in articulatory lip movement induced by preceding auditory feedback during production of bilabial plosives.

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    Takemi Mochida

    Full Text Available BACKGROUND: There has been plentiful evidence of kinesthetically induced rapid compensation for unanticipated perturbation in speech articulatory movements. However, the role of auditory information in stabilizing articulation has been little studied except for the control of voice fundamental frequency, voice amplitude and vowel formant frequencies. Although the influence of auditory information on the articulatory control process is evident in unintended speech errors caused by delayed auditory feedback, the direct and immediate effect of auditory alteration on the movements of articulators has not been clarified. METHODOLOGY/PRINCIPAL FINDINGS: This work examined whether temporal changes in the auditory feedback of bilabial plosives immediately affects the subsequent lip movement. We conducted experiments with an auditory feedback alteration system that enabled us to replace or block speech sounds in real time. Participants were asked to produce the syllable /pa/ repeatedly at a constant rate. During the repetition, normal auditory feedback was interrupted, and one of three pre-recorded syllables /pa/, /Φa/, or /pi/, spoken by the same participant, was presented once at a different timing from the anticipated production onset, while no feedback was presented for subsequent repetitions. Comparisons of the labial distance trajectories under altered and normal feedback conditions indicated that the movement quickened during the short period immediately after the alteration onset, when /pa/ was presented 50 ms before the expected timing. Such change was not significant under other feedback conditions we tested. CONCLUSIONS/SIGNIFICANCE: The earlier articulation rapidly induced by the progressive auditory input suggests that a compensatory mechanism helps to maintain a constant speech rate by detecting errors between the internally predicted and actually provided auditory information associated with self movement. The timing- and context

  15. ON FEEDBACK CONTROL OF DELAYED CHAOTIC SYSTEM

    Institute of Scientific and Technical Information of China (English)

    李丽香; 彭海朋; 卢辉斌; 关新平

    2001-01-01

    In this paper two different types of feedback control technique are discussed: the standard feedback control and the time-delay feedback control which have been successfully used in many control systems. In order to understand to what extent the two different types of control technique are useful in delayed chaotic systems, some analytic stabilization conditions for chaos control from the two types of control technique are derived based on Lyapunov stabilization arguments. Similarly, we discuss the tracking problem by applying the time-delay feedback control. Finally, numerical examples are provided.

  16. Anharmonic resonances with recursive delay feedback

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    Goldobin, Denis S., E-mail: Denis.Goldobin@gmail.com [Department of Mathematics, University of Leicester, Leicester LE1 7RH (United Kingdom); Institute of Continuous Media Mechanics, UB RAS, Perm 614013 (Russian Federation)

    2011-09-12

    We consider application of time-delayed feedback with infinite recursion for control of anharmonic (nonlinear) oscillators subject to noise. In contrast to the case of a single delay feedback, recursive delay feedback exhibits resonances between feedback and nonlinear harmonics, leading to a resonantly strong or weak oscillation coherence even for a small anharmonicity. Remarkably, these small-anharmonicity induced resonances can be stronger than the harmonic ones. Analytical results are confirmed numerically for van der Pol and van der Pol-Duffing oscillators. -- Highlights: → We construct general theory of noisy limit-cycle oscillators with linear feedback. → We focus on coherence and 'reliability' of oscillators. → For recursive delay feedback control the theory shows importance of anharmonicity. → Anharmonic resonances are studied both numerically and analytically.

  17. Using on-line altered auditory feedback treating Parkinsonian speech

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    Wang, Emily; Verhagen, Leo; de Vries, Meinou H.

    2005-09-01

    Patients with advanced Parkinson's disease tend to have dysarthric speech that is hesitant, accelerated, and repetitive, and that is often resistant to behavior speech therapy. In this pilot study, the speech disturbances were treated using on-line altered feedbacks (AF) provided by SpeechEasy (SE), an in-the-ear device registered with the FDA for use in humans to treat chronic stuttering. Eight PD patients participated in the study. All had moderate to severe speech disturbances. In addition, two patients had moderate recurring stuttering at the onset of PD after long remission since adolescence, two had bilateral STN DBS, and two bilateral pallidal DBS. An effective combination of delayed auditory feedback and frequency-altered feedback was selected for each subject and provided via SE worn in one ear. All subjects produced speech samples (structured-monologue and reading) under three conditions: baseline, with SE without, and with feedbacks. The speech samples were randomly presented and rated for speech intelligibility goodness using UPDRS-III item 18 and the speaking rate. The results indicted that SpeechEasy is well tolerated and AF can improve speech intelligibility in spontaneous speech. Further investigational use of this device for treating speech disorders in PD is warranted [Work partially supported by Janus Dev. Group, Inc.].

  18. Representation of Reward Feedback in Primate Auditory Cortex

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    Michael eBrosch

    2011-02-01

    Full Text Available It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1 the reward expectancy for each trial, (2 the reward size received and (3 the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

  19. Representation of reward feedback in primate auditory cortex.

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    Brosch, Michael; Selezneva, Elena; Scheich, Henning

    2011-01-01

    It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1) the reward expectancy for each trial, (2) the reward-size received, and (3) the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

  20. Feedback Control of Chaos in Delay Maps

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, we discuss feedback control of a class of delay chaotic maps. Our aim is to drive the chaoticmaps to its initially unstable fixed points by using linear and nonlinear state feedback control. The control is achievedby using small, bounded perturbations. Some numerical simulations are given to demonstrate the effectiveness of theproposed control method.

  1. Speech Compensation for Time-Scale-Modified Auditory Feedback

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    Ogane, Rintaro; Honda, Masaaki

    2014-01-01

    Purpose: The purpose of this study was to examine speech compensation in response to time-scale-modified auditory feedback during the transition of the semivowel for a target utterance of /ija/. Method: Each utterance session consisted of 10 control trials in the normal feedback condition followed by 20 perturbed trials in the modified auditory…

  2. Feedback valence affects auditory perceptual learning independently of feedback probability

    OpenAIRE

    Amitay, S.; Moore, D. R.; Molloy, K.; Halliday, L. F.

    2015-01-01

    Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they wer...

  3. Brain responses to altered auditory feedback during musical keyboard production: an fMRI study.

    Science.gov (United States)

    Pfordresher, Peter Q; Mantell, James T; Brown, Steven; Zivadinov, Robert; Cox, Jennifer L

    2014-03-27

    Alterations of auditory feedback during piano performance can be profoundly disruptive. Furthermore, different alterations can yield different types of disruptive effects. Whereas alterations of feedback synchrony disrupt performed timing, alterations of feedback pitch contents can disrupt accuracy. The current research tested whether these behavioral dissociations correlate with differences in brain activity. Twenty pianists performed simple piano keyboard melodies while being scanned in a 3-T magnetic resonance imaging (MRI) scanner. In different conditions they experienced normal auditory feedback, altered auditory feedback (asynchronous delays or altered pitches), or control conditions that excluded movement or sound. Behavioral results replicated past findings. Neuroimaging data suggested that asynchronous delays led to increased activity in Broca's area and its right homologue, whereas disruptive alterations of pitch elevated activations in the cerebellum, area Spt, inferior parietal lobule, and the anterior cingulate cortex. Both disruptive conditions increased activations in the supplementary motor area. These results provide the first evidence of neural responses associated with perception/action mismatch during keyboard production.

  4. Task-irrelevant auditory feedback facilitates motor performance in musicians

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    Virginia eConde

    2012-05-01

    Full Text Available An efficient and fast auditory–motor network is a basic resource for trained musicians due to the importance of motor anticipation of sound production in musical performance. When playing an instrument, motor performance always goes along with the production of sounds and the integration between both modalities plays an essential role in the course of musical training. The aim of the present study was to investigate the role of task-irrelevant auditory feedback during motor performance in musicians using a serial reaction time task (SRTT. Our hypothesis was that musicians, due to their extensive auditory–motor practice routine during musical training, have a superior performance and learning capabilities when receiving auditory feedback during SRTT relative to musicians performing the SRTT without any auditory feedback. Here we provide novel evidence that task-irrelevant auditory feedback is capable to reinforce SRTT performance but not learning, a finding that might provide further insight into auditory-motor integration in musicians on a behavioral level.

  5. Delayed feedback control in quantum transport.

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    Emary, Clive

    2013-09-28

    Feedback control in quantum transport has been predicted to give rise to several interesting effects, among them quantum state stabilization and the realization of a mesoscopic Maxwell's daemon. These results were derived under the assumption that control operations on the system are affected instantaneously after the measurement of electronic jumps through it. In this contribution, I describe how to include a delay between detection and control operation in the master equation theory of feedback-controlled quantum transport. I investigate the consequences of delay for the state stabilization and Maxwell's daemon schemes. Furthermore, I describe how delay can be used as a tool to probe coherent oscillations of electrons within a transport system and how this formalism can be used to model finite detector bandwidth.

  6. Formant compensation for auditory feedback with English vowels

    DEFF Research Database (Denmark)

    Mitsuya, Takashi; MacDonald, Ewen N; Munhall, Kevin G;

    2015-01-01

    Past studies have shown that speakers spontaneously adjust their speech acoustics in response to their auditory feedback perturbed in real time. In the case of formant perturbation, the majority of studies have examined speaker's compensatory production using the English vowel /ɛ/ as in the word...... to differences in the degree of lingual contact or jaw openness. This may in turn influence the ways in which speakers compensate for auditory feedback. The aim of the current study was to examine speakers' compensatory behavior with six English monophthongs. Specifically, the current study tested to see...

  7. Theoretical feasibility of suppressing offensive sports chants by means of delayed feedback of sound

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Balken, J.A. van

    2007-01-01

    A novel approach for disrupting offensive chants at sporting events is proposed, based on attacking synchronization between individuals. Since timing is crucial for coordination between chanters, disruption of timing is expected to be effective against undesired chants. Delayed auditory feedback is

  8. Partial Compensation for Altered Auditory Feedback: A Tradeoff with Somatosensory Feedback?

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    Katseff, Shira; Houde, John; Johnson, Keith

    2012-01-01

    Talkers are known to compensate only partially for experimentally-induced changes to their auditory feedback. In a typical experiment, talkers might hear their F1 feedback shifted higher (so that /[epsilon]/ sounds like /[ash]/, for example), and compensate by lowering F1 in their subsequent speech by about a quarter of that distance. Here, we…

  9. Delayed feedback on tax audits affects compliance and fairness perceptions

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    Kogler, C.; Mittone, Luigi; Kirchler, Erich

    2016-01-01

    In the present study we explore the conflicting finding that delayed feedback on tax audits apparently results in higher tax compliance, although delaying feedback is associated with lower perceptions of procedural fairness. In a repeated rounds design the timing of feedback (delayed vs. immediate)

  10. Effects of altered auditory feedback across effector systems: production of melodies by keyboard and singing.

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    Pfordresher, Peter Q; Mantell, James T

    2012-01-01

    We report an experiment that tested whether effects of altered auditory feedback (AAF) during piano performance differ from its effects during singing. These effector systems differ with respect to the mapping between motor gestures and pitch content of auditory feedback. Whereas this action-effect mapping is highly reliable during phonation in any vocal motor task (singing or speaking), mapping between finger movements and pitch occurs only in limited situations, such as piano playing. Effects of AAF in both tasks replicated results previously found for keyboard performance (Pfordresher, 2003), in that asynchronous (delayed) feedback slowed timing whereas alterations to feedback pitch increased error rates, and the effect of asynchronous feedback was similar in magnitude across tasks. However, manipulations of feedback pitch had larger effects on singing than on keyboard production, suggesting effector-specific differences in sensitivity to action-effect mapping with respect to feedback content. These results support the view that disruption from AAF is based on abstract, effector independent, response-effect associations but that the strength of associations differs across effector systems.

  11. Intensity of guitar playing as a function of auditory feedback.

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    Johnson, C I; Pick, H L; Garber, S R; Siegel, G M

    1978-06-01

    Subjects played an electric guitar while auditory feedback was attenuated or amplified at seven sidetone levels varying 10-dB steps around a comfortable listening level. The sidetone signal was presented in quiet (experiment I) and several levels of white noise (experiment II). Subjects compensated for feedback changes, demonstrating a sidetone amplification as well as a Lombard effect. The similarity of these results to those found previously for speech suggests that guitar playing can be a useful analog for the function of auditory feedback in speech production. Unlike previous findings for speech, the sidetone-amplification effect was not potentiated by masking, consistent with a hypothesis that potentiation in speech is attributable to interference with bone conduction caused by the masking noise.

  12. Nonlinear dynamics of neural delayed feedback

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    Longtin, A.

    1990-01-01

    Neural delayed feedback is a property shared by many circuits in the central and peripheral nervous systems. The evolution of the neural activity in these circuits depends on their present state as well as on their past states, due to finite propagation time of neural activity along the feedback loop. These systems are often seen to undergo a change from a quiescent state characterized by low level fluctuations to an oscillatory state. We discuss the problem of analyzing this transition using techniques from nonlinear dynamics and stochastic processes. Our main goal is to characterize the nonlinearities which enable autonomous oscillations to occur and to uncover the properties of the noise sources these circuits interact with. The concepts are illustrated on the human pupil light reflex (PLR) which has been studied both theoretically and experimentally using this approach. 5 refs., 3 figs.

  13. LHC One-turn Delay Feedback Commissioning

    CERN Document Server

    Mastoridis, T; Molendijk, J

    2012-01-01

    The LHC One-Turn delay FeedBack (OTFB) is an FPGA based feedback system part of the LHC cavity controller, which produces gain only around the revolution frequency (frev = 11.245 kHz) harmonics. As such, it helps reduce the transient beam loading and effective cavity impedance. Consequently, it increases the stability margin for Longitudinal Coupled Bunch Instabilities driven by the cavity impedance at the fundamental and allows reliable operation at higher beam currents. The OTFB was commissioned on all sixteen cavities in mid-October 2011 and has been used in operation since. The commissioning procedure and algorithms for setting-up are presented. The resulting improvements in transient beam loading, beam stability, and required klystron power are analyzed. The commissioning of the OTFB reduced the cavity voltage phase modulation from approximately six degrees peak-to-peak to below one degree at 400 MHz with nominal bunch intensity of 1.1e11 protons.

  14. Effect of auditory feedback on speech production after cochlear implantation

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    Sheikh Zadeh H

    2001-10-01

    Full Text Available The main goal of this study is to determine the auditory feedback effects in improvement of speech production process in prelingual totally deaf children who used cochlear implant prosthesis. For this reason, we recorded speech of four prelingual cochlear implant children pre and post of operation. Then we extract some static features of vowels-such as fundamental frequency, formant frequencies, vowel duration and vowel energy-from their stable mid-section and analyze them using a longitudinal prosthesis-on/off analysis. These patients-where are in the range of 7-13 years old-were operated in the cochlear implant clinic of Amiralam hospital. At each session, patients read the sentences once in device-on condition and then after 30 minutes stay in device-off condition. Quantitative results show that at least for the features under study, the patient's reliance on the auditory feedback decreased consistently by time (about 65%-averaged on all three vowels under study and all patients. So we concluded that after a sufficient time of operation, the speech motor patterns of patients will be trained for the correct production of static features of vowels and the relation of patients to auditory feedback for the production of such features considerably decreased by time.

  15. Different Auditory Feedback Control for Echolocation and Communication in Horseshoe Bats

    OpenAIRE

    Ying Liu; Jiang Feng; Walter Metzner

    2013-01-01

    Auditory feedback from the animal's own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Auditory feedback seems also necessary for controlling many bat communication calls, although it remains unclear how auditory feedback control differs in echolocation and communication. We tackled this question by analyzing echolocation and communication in greater horseshoe bats, whose echoloca...

  16. H∞ State Feedback Delay-dependent Control for Discrete Systems with Multi-time-delay

    Institute of Scientific and Technical Information of China (English)

    Bai-Da Qu

    2005-01-01

    In this paper,H∞ state feedback control with delay information for discrete systems with multi-time-delay is discussed. Making use of linear matrix inequality (LMI) approach, a time-delay-dependent criterion for a discrete system with multi-time-delay to satisfy H∞ performance indices is induced, and then a strategy for H∞ state feedback control with delay values for plant with multi-time-delay is obtained. By solving corresponding LMI, a delay-dependent state feedback controller satisfying H∞ performance indices is designed. Finally, a simulation example demonstrates the validity of the proposed approach.

  17. Weighting of Auditory Feedback Across the English Vowel Space

    OpenAIRE

    Purcell, David; Munhall, Kevin

    2008-01-01

    Auditory feedback in the headphones of talkers was manipulated in the F1 dimension using a real-time vowel formant filtering system. Minimum formant shifts required to elicit a response and the amount of compensation were measured for vowels across the English vowel space. The largest response in production of F1 was observed for the vowel /ε/ and smaller or non-significant changes were found for point vowels. In general, changes in production were of a compensatory nature that reduced the er...

  18. Time-delay feedback control in a delayed dynamical chaos system and its applications

    Institute of Scientific and Technical Information of China (English)

    Ye Zhi-Yong; Yang Guang; Deng Cun-Bing

    2011-01-01

    The feedback control of a delayed dynamical system, which also includes various chaotic systems with time delays, is investigated. On the basis of stability analysis of a nonautonomons system with delays, some simple yet less conservative criteria are obtained for feedback control in a delayed dynamical system. Finally, the theoretical result is applied to a typical class of chaotic Lorenz system and Chua circuit with delays. Numerical simulations are also given to verify the theoretical results.

  19. Weak responses to auditory feedback perturbation during articulation in persons who stutter: evidence for abnormal auditory-motor transformation.

    Directory of Open Access Journals (Sweden)

    Shanqing Cai

    Full Text Available Previous empirical observations have led researchers to propose that auditory feedback (the auditory perception of self-produced sounds when speaking functions abnormally in the speech motor systems of persons who stutter (PWS. Researchers have theorized that an important neural basis of stuttering is the aberrant integration of auditory information into incipient speech motor commands. Because of the circumstantial support for these hypotheses and the differences and contradictions between them, there is a need for carefully designed experiments that directly examine auditory-motor integration during speech production in PWS. In the current study, we used real-time manipulation of auditory feedback to directly investigate whether the speech motor system of PWS utilizes auditory feedback abnormally during articulation and to characterize potential deficits of this auditory-motor integration. Twenty-one PWS and 18 fluent control participants were recruited. Using a short-latency formant-perturbation system, we examined participants' compensatory responses to unanticipated perturbation of auditory feedback of the first formant frequency during the production of the monophthong [ε]. The PWS showed compensatory responses that were qualitatively similar to the controls' and had close-to-normal latencies (∼150 ms, but the magnitudes of their responses were substantially and significantly smaller than those of the control participants (by 47% on average, p<0.05. Measurements of auditory acuity indicate that the weaker-than-normal compensatory responses in PWS were not attributable to a deficit in low-level auditory processing. These findings are consistent with the hypothesis that stuttering is associated with functional defects in the inverse models responsible for the transformation from the domain of auditory targets and auditory error information into the domain of speech motor commands.

  20. The Effect of Gender on the N1-P2 Auditory Complex while Listening and Speaking with Altered Auditory Feedback

    Science.gov (United States)

    Swink, Shannon; Stuart, Andrew

    2012-01-01

    The effect of gender on the N1-P2 auditory complex was examined while listening and speaking with altered auditory feedback. Fifteen normal hearing adult males and 15 females participated. N1-P2 components were evoked while listening to self-produced nonaltered and frequency shifted /a/ tokens and during production of /a/ tokens during nonaltered…

  1. Air pollution is associated with brainstem auditory nuclei pathology and delayed brainstem auditory evoked potentials

    OpenAIRE

    Calderón-Garcidueñas, Lilian; D’Angiulli, Amedeo; Kulesza, Randy J.; Torres-Jardón, Ricardo; Osnaya, Norma; Romero, Lina; Keefe, Sheyla; Herritt, Lou; Brooks, Diane M.; Avila-Ramirez, Jose; Delgado-Chávez, Ricardo; Medina-Cortina, Humberto; González-González, Luis Oscar

    2011-01-01

    We assessed brainstem inflammation in children exposed to air pollutants by comparing brainstem auditory evoked potentials (BAEPs) and blood inflammatory markers in children age 96.3± 8.5 months from highly polluted (n=34) versus a low polluted city (n=17). The brainstems of nine children with accidental deaths were also examined. Children from the highly polluted environment had significant delays in wave III (t(50)=17.038; p

  2. Delayed feedback model of axonal length sensing.

    Science.gov (United States)

    Karamched, Bhargav R; Bressloff, Paul C

    2015-05-05

    A fundamental question in cell biology is how the sizes of cells and organelles are regulated at various stages of development. Size homeostasis is particularly challenging for neurons, whose axons can extend from hundreds of microns to meters (in humans). Recently, a molecular-motor-based mechanism for axonal length sensing has been proposed, in which axonal length is encoded by the frequency of an oscillating retrograde signal. In this article, we develop a mathematical model of this length-sensing mechanism in which advection-diffusion equations for bidirectional motor transport are coupled to a chemical signaling network. We show that chemical oscillations emerge due to delayed negative feedback via a Hopf bifurcation, resulting in a frequency that is a monotonically decreasing function of axonal length. Knockdown of either kinesin or dynein causes an increase in the oscillation frequency, suggesting that the length-sensing mechanism would produce longer axons, which is consistent with experimental findings. One major prediction of the model is that fluctuations in the transport of molecular motors lead to a reduction in the reliability of the frequency-encoding mechanism for long axons. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Time-delay identification for vibration systems with multiple feedback

    Science.gov (United States)

    Sun, Yi-Qiang; Jin, Meng-Shi; Song, Han-Wen; Xu, Jian

    2016-12-01

    An approach for time-delay identification is proposed in multiple-degree-of-freedom (MDOF) linear systems with multiple feedback. The applicability of the approach is discussed in detail. Based on the characteristics of frequency domain in feedback controlled system with multiple time-delays, this paper proposes a time-delay identification approach, which is based on the pseudo impedance function of reference point. Treating feedback time-delays as the "frequencies" of the oscillation curve, the time-delays can be obtained from the "frequencies" of the curve. Numerical simulation is conducted to validate the proposed approach. The application scope of the approach is discussed with regard to different forms of feedback.

  4. Time-delay identification for vibration systems with multiple feedback

    Institute of Scientific and Technical Information of China (English)

    Yi-Qiang Sun; Meng-Shi Jin; Han-Wen Song; Jian Xu

    2016-01-01

    An approach for time-delay identification is pro-posed in multiple-degree-of-freedom (MDOF) linear sys-tems with multiple feedback. The applicability of the approach is discussed in detail. Based on the characteris-tics of frequency domain in feedback controlled system with multiple time-delays, this paper proposes a time-delay iden-tification approach, which is based on the pseudo impedance function of reference point. Treating feedback time-delays as the“frequencies”of the oscillation curve, the time-delays can be obtained from the“frequencies”of the curve. Numerical simulation is conducted to validate the proposed approach. The application scope of the approach is discussed with regard to different forms of feedback.

  5. Variable-delay feedback control of unstable steady states in retarded time-delayed systems

    CERN Document Server

    Gjurchinovski, Aleksandar; 10.1103/PhysRevE.81.016209

    2010-01-01

    We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.

  6. Dynamical behaviour of Liu system with time delayed feedback

    Institute of Scientific and Technical Information of China (English)

    Qian Qin; Wang Lin; Ni Qiao

    2008-01-01

    This paper investigates the dynamical behaviour of the Liu system with time delayed feedback.Two typical situations are considered and the effect of time-delay parameter on the dynamics of the system is discussed.It is shown that the Liu system with time delayed feedback may exhibit interesting and extremely rich dynamical behaviour.The evolution of the dynamics is shown to be complex with varying time-delay parameter.Moreover,the strange attractor like 'wormhole' is detected via numerical simulations.

  7. Stabilizing unstable steady states using multiple delay feedback control.

    Science.gov (United States)

    Ahlborn, Alexander; Parlitz, Ulrich

    2004-12-31

    Feedback control with different and independent delay times is introduced and shown to be an efficient method for stabilizing fixed points (equilibria) of dynamical systems. In comparison to other delay based chaos control methods multiple delay feedback control is superior for controlling steady states and works also for relatively large delay times (sometimes unavoidable in experiments due to system dead times). To demonstrate this approach for stabilizing unstable fixed points we present numerical simulations of Chua's circuit and a successful experimental application for stabilizing a chaotic frequency doubled Nd-doped yttrium aluminum garnet laser.

  8. Effects of Feedback Timing on Second Language Vocabulary Learning: Does Delaying Feedback Increase Learning?

    Science.gov (United States)

    Nakata, Tatsuya

    2015-01-01

    Feedback, or information given to learners regarding their performance, is found to facilitate second language (L2) learning. Research also suggests that the timing of feedback (whether it is provided immediately or after a delay) may affect learning. The purpose of the present study was to identify the optimal feedback timing for L2 vocabulary…

  9. The Effects of Delay of Feedback on a Delayed Concept Formation Transfer Task.

    Science.gov (United States)

    Schroth, Marvin L.

    1992-01-01

    Delay and completeness of verbal information feedback were investigated within a transfer of learning paradigm involving concept formation. An experiment with 192 undergraduates indicates that, although delay of feedback (up to 30 seconds) slows speed of learning on the initial task, it has positive effects on the transfer task. (SLD)

  10. Auditory feedback and memory for music performance: sound evidence for an encoding effect.

    Science.gov (United States)

    Finney, Steven A; Palmer, Caroline

    2003-01-01

    Research on the effects of context and task on learning and memory has included approaches that emphasize processes during learning (e.g., Craik & Tulving, 1975) and approaches that emphasize a match of conditions during learning with conditions during a later test of memory (e.g., Morris, Bransford, & Franks, 1977; Proteau, 1992; Tulving & Thomson, 1973). We investigated the effects of auditory context on learning and retrieval in three experiments on memorized music performance (a form of serial recall). Auditory feedback (presence or absence) was manipulated while pianists learned musical pieces from notation and when they later played the pieces from memory. Auditory feedback during learning significantly improved later recall. However, auditory feedback at test did not significantly affect recall, nor was there an interaction between conditions at learning and test. Auditory feedback in music performance appears to be a contextual factor that affects learning but is relatively independent of retrieval conditions.

  11. Delayed excitatory and inhibitory feedback shape neural information transmission

    Science.gov (United States)

    Chacron, Maurice J.; Longtin, André; Maler, Leonard

    2017-01-01

    Feedback circuitry with conduction and synaptic delays is ubiquitous in the nervous system. Yet the effects of delayed feedback on sensory processing of natural signals are poorly understood. This study explores the consequences of delayed excitatory and inhibitory feedback inputs on the processing of sensory information. We show, through numerical simulations and theory, that excitatory and inhibitory feedback can alter the firing frequency response of stochastic neurons in opposite ways by creating dynamical resonances, which in turn lead to information resonances (i.e., increased information transfer for specific ranges of input frequencies). The resonances are created at the expense of decreased information transfer in other frequency ranges. Using linear response theory for stochastically firing neurons, we explain how feedback signals shape the neural transfer function for a single neuron as a function of network size. We also find that balanced excitatory and inhibitory feedback can further enhance information tuning while maintaining a constant mean firing rate. Finally, we apply this theory to in vivo experimental data from weakly electric fish in which the feedback loop can be opened. We show that it qualitatively predicts the observed effects of inhibitory feedback. Our study of feedback excitation and inhibition reveals a possible mechanism by which optimal processing may be achieved over selected frequency ranges. PMID:16383655

  12. Effects of visual and auditory feedback on sensorimotor circuits in the basal ganglia.

    Science.gov (United States)

    Prodoehl, Janey; Yu, Hong; Wasson, Pooja; Corcos, Daniel M; Vaillancourt, David E

    2008-06-01

    Previous work using visual feedback has identified two distinct sensorimotor circuits in the basal ganglia (BG): one that scaled with the duration of force and one that scaled with the rate of change of force. The present study compared functional MRI signal changes in the BG during a grip force task using either visual or auditory feedback to determine whether the BG nuclei process auditory and visual feedback similarly. We confirmed the same two sensorimotor circuits in the BG. Activation in the striatum and external globus pallidus (GPe) scaled linearly with the duration of force under visual and auditory feedback conditions, with similar slopes and intercepts across feedback type. The pattern of signal change for the internal globus pallidus (GPi) and subthalamic nucleus (STN) was nonlinear and parameters of the exponential function were altered by feedback type. Specifically, GPi and STN activation decreased exponentially with the rate of change of force. The rate constant and asymptote of the exponential functions for GPi and STN were greater during auditory than visual feedback. In a comparison of the BOLD signal between BG regions, GPe had the highest percentage of variance accounted for and this effect was preserved for both feedback types. These new findings suggest that neuronal activity of specific BG nuclei is affected by whether the feedback is derived from visual or auditory inputs. Also, the data are consistent with the hypothesis that the GPe has a high level of information convergence from other BG nuclei, which is preserved across different sensory feedback modalities.

  13. Temporal coordination in joint music performance: effects of endogenous rhythms and auditory feedback.

    Science.gov (United States)

    Zamm, Anna; Pfordresher, Peter Q; Palmer, Caroline

    2015-02-01

    Many behaviors require that individuals coordinate the timing of their actions with others. The current study investigated the role of two factors in temporal coordination of joint music performance: differences in partners' spontaneous (uncued) rate and auditory feedback generated by oneself and one's partner. Pianists performed melodies independently (in a Solo condition), and with a partner (in a duet condition), either at the same time as a partner (Unison), or at a temporal offset (Round), such that pianists heard their partner produce a serially shifted copy of their own sequence. Access to self-produced auditory information during duet performance was manipulated as well: Performers heard either full auditory feedback (Full), or only feedback from their partner (Other). Larger differences in partners' spontaneous rates of Solo performances were associated with larger asynchronies (less effective synchronization) during duet performance. Auditory feedback also influenced temporal coordination of duet performance: Pianists were more coordinated (smaller tone onset asynchronies and more mutual adaptation) during duet performances when self-generated auditory feedback aligned with partner-generated feedback (Unison) than when it did not (Round). Removal of self-feedback disrupted coordination (larger tone onset asynchronies) during Round performances only. Together, findings suggest that differences in partners' spontaneous rates of Solo performances, as well as differences in self- and partner-generated auditory feedback, influence temporal coordination of joint sensorimotor behaviors.

  14. Time-Delay Systems with Band-Limited Feedback

    Science.gov (United States)

    2005-08-01

    used as generators of chaos in applications such as communication, chaos control , and ranging. As an example, such devices are studied as a signal...tions [Lukin, 1997; Myneni, 2001]. Furthermore, time delayed feedback is used in the chaos control scheme known as time-delay autosynchronization

  15. Sensorimotor learning in children and adults: Exposure to frequency-altered auditory feedback during speech production.

    Science.gov (United States)

    Scheerer, N E; Jacobson, D S; Jones, J A

    2016-02-09

    Auditory feedback plays an important role in the acquisition of fluent speech; however, this role may change once speech is acquired and individuals no longer experience persistent developmental changes to the brain and vocal tract. For this reason, we investigated whether the role of auditory feedback in sensorimotor learning differs across children and adult speakers. Participants produced vocalizations while they heard their vocal pitch predictably or unpredictably shifted downward one semitone. The participants' vocal pitches were measured at the beginning of each vocalization, before auditory feedback was available, to assess the extent to which the deviant auditory feedback modified subsequent speech motor commands. Sensorimotor learning was observed in both children and adults, with participants' initial vocal pitch increasing following trials where they were exposed to predictable, but not unpredictable, frequency-altered feedback. Participants' vocal pitch was also measured across each vocalization, to index the extent to which the deviant auditory feedback was used to modify ongoing vocalizations. While both children and adults were found to increase their vocal pitch following predictable and unpredictable changes to their auditory feedback, adults produced larger compensatory responses. The results of the current study demonstrate that both children and adults rapidly integrate information derived from their auditory feedback to modify subsequent speech motor commands. However, these results also demonstrate that children and adults differ in their ability to use auditory feedback to generate compensatory vocal responses during ongoing vocalization. Since vocal variability also differed across the children and adult groups, these results also suggest that compensatory vocal responses to frequency-altered feedback manipulations initiated at vocalization onset may be modulated by vocal variability. Copyright © 2015 IBRO. Published by Elsevier Ltd. All

  16. Truncated predictor feedback for time-delay systems

    CERN Document Server

    Zhou, Bin

    2014-01-01

    This book provides a systematic approach to the design of predictor based controllers for (time-varying) linear systems with either (time-varying) input or state delays. Differently from those traditional predictor based controllers, which are infinite-dimensional static feedback laws and may cause difficulties in their practical implementation, this book develops a truncated predictor feedback (TPF) which involves only finite dimensional static state feedback. Features and topics: A novel approach referred to as truncated predictor feedback for the stabilization of (time-varying) time-delay systems in both the continuous-time setting and the discrete-time setting is built systematically Semi-global and global stabilization problems of linear time-delay systems subject to either magnitude saturation or energy constraints are solved in a systematic manner Both stabilization of a single system and consensus of a group of systems (multi-agent systems) are treated in a unified manner by applying the truncated pre...

  17. Effect of task-related continuous auditory feedback during learning of tracking motion exercises

    Directory of Open Access Journals (Sweden)

    Rosati Giulio

    2012-10-01

    Full Text Available Abstract Background This paper presents the results of a set of experiments in which we used continuous auditory feedback to augment motor training exercises. This feedback modality is mostly underexploited in current robotic rehabilitation systems, which usually implement only very basic auditory interfaces. Our hypothesis is that properly designed continuous auditory feedback could be used to represent temporal and spatial information that could in turn, improve performance and motor learning. Methods We implemented three different experiments on healthy subjects, who were asked to track a target on a screen by moving an input device (controller with their hand. Different visual and auditory feedback modalities were envisaged. The first experiment investigated whether continuous task-related auditory feedback can help improve performance to a greater extent than error-related audio feedback, or visual feedback alone. In the second experiment we used sensory substitution to compare different types of auditory feedback with equivalent visual feedback, in order to find out whether mapping the same information on a different sensory channel (the visual channel yielded comparable effects with those gained in the first experiment. The final experiment applied a continuously changing visuomotor transformation between the controller and the screen and mapped kinematic information, computed in either coordinate system (controller or video, to the audio channel, in order to investigate which information was more relevant to the user. Results Task-related audio feedback significantly improved performance with respect to visual feedback alone, whilst error-related feedback did not. Secondly, performance in audio tasks was significantly better with respect to the equivalent sensory-substituted visual tasks. Finally, with respect to visual feedback alone, video-task-related sound feedback decreased the tracking error during the learning of a novel

  18. Conversion of linear time-invariant time-delay feedback systems into delay-differential equations with commensurate delays

    Science.gov (United States)

    Yamazaki, Tatsuya; Hagiwara, Tomomichi

    2014-08-01

    A new stability analysis method of time-delay systems (TDSs) called the monodromy operator approach has been studied under the assumption that a TDS is represented as a time-delay feedback system consisting of a finite-dimensional linear time-invariant (LTI) system and a pure delay. For applying this approach to TDSs described by delay-differential equations (DDEs), the problem of converting DDEs into representation as time-delay feedback systems has been studied. With regard to such a problem, it was shown that, under discontinuous initial functions, it is natural to define the solutions of DDEs in two different ways, and the above conversion problem was solved for each of these two definitions. More precisely, the solution of a DDE was represented as either the state of the finite-dimensional part of a time-delay feedback system or a part of the output of another time-delay feedback system, depending on which definition of the DDE solution one is talking about. Motivated by the importance in establishing a thorough relationship between time-delay feedback systems and DDEs, this paper discusses the opposite problem of converting time-delay feedback systems into representation as DDEs, including the discussions about the conversion of the initial conditions. We show that the state of (the finite-dimensional part of) a time-delay feedback system can be represented as the solution of a DDE in the sense of one of the two definitions, while its 'essential' output can be represented as that of another DDE in the sense of the other type of definition. Rigorously speaking, however, it is also shown that the latter representation is possible regardless of the initial conditions, while some initial condition could prevent the conversion into the former representation. This study hence establishes that the representation of TDSs as time-delay feedback systems possesses higher ability than that with DDEs, as description methods for LTI TDSs with commensurate delays.

  19. Augmented visual, auditory, haptic, and multimodal feedback in motor learning: A review

    National Research Council Canada - National Science Library

    Sigrist, Roland; Rauter, Georg; Riener, Robert; Wolf, Peter

    2013-01-01

    .... Recently, technical advances have made it possible also to investigate more complex, realistic motor tasks and to implement not only visual, but also auditory, haptic, or multimodal augmented feedback...

  20. Effects of auditory feedback during gait training on hemiplegic patients' weight bearing and dynamic balance ability.

    Science.gov (United States)

    Ki, Kyong-Il; Kim, Mi-Sun; Moon, Young; Choi, Jong-Duk

    2015-04-01

    [Purpose] This study examined the effects of auditory feedback during gait on the weight bearing of patients with hemiplegia resulting from a stroke. [Subjects] Thirty hemiplegic patients participated in this experiment and they were randomly allocated to an experimental group and a control group. [Methods] Both groups received neuro-developmental treatment for four weeks and the experimental group additionally received auditory feedback during gait training. In order to examine auditory feedback effects on weight bearing during gait, a motion analysis system GAITRite was used to measure the duration of the stance phase and single limb stance phase of the subjects. [Results] The experimental group showed statistically significant improvements in the duration of the stance phase and single limb stance phase of the paretic side and the results of the Timed Up and Go Test after the training. [Conclusion] Auditory feedback during gait training significantly improved the duration of the stance phase and single limb stance phase of hemiplegic stroke patients.

  1. Selective and divided attention modulates auditory-vocal integration in the processing of pitch feedback errors.

    Science.gov (United States)

    Liu, Ying; Hu, Huijing; Jones, Jeffery A; Guo, Zhiqiang; Li, Weifeng; Chen, Xi; Liu, Peng; Liu, Hanjun

    2015-08-01

    Speakers rapidly adjust their ongoing vocal productions to compensate for errors they hear in their auditory feedback. It is currently unclear what role attention plays in these vocal compensations. This event-related potential (ERP) study examined the influence of selective and divided attention on the vocal and cortical responses to pitch errors heard in auditory feedback regarding ongoing vocalisations. During the production of a sustained vowel, participants briefly heard their vocal pitch shifted up two semitones while they actively attended to auditory or visual events (selective attention), or both auditory and visual events (divided attention), or were not told to attend to either modality (control condition). The behavioral results showed that attending to the pitch perturbations elicited larger vocal compensations than attending to the visual stimuli. Moreover, ERPs were likewise sensitive to the attentional manipulations: P2 responses to pitch perturbations were larger when participants attended to the auditory stimuli compared to when they attended to the visual stimuli, and compared to when they were not explicitly told to attend to either the visual or auditory stimuli. By contrast, dividing attention between the auditory and visual modalities caused suppressed P2 responses relative to all the other conditions and caused enhanced N1 responses relative to the control condition. These findings provide strong evidence for the influence of attention on the mechanisms underlying the auditory-vocal integration in the processing of pitch feedback errors. In addition, selective attention and divided attention appear to modulate the neurobehavioral processing of pitch feedback errors in different ways.

  2. Delay-dependent state feedback robust stabilization for uncertain singular time-delay systems

    Institute of Scientific and Technical Information of China (English)

    Gao Huanli; Xu Bugong

    2008-01-01

    The problem of robust stabilization for uncertain singular time-delay systems is studied.First,a new delay-dependent asymptotic stability criteria for normal singular time-delay systems is given,which is less conservative.Using this result,the problem of state feedback robust stabilization for uncertain singular time-delay systems is discussed.Finally,two examples are given to illustrate the effectiveness of the results.

  3. Ring a bell? Adaptive Auditory Game Feedback to Sustain Performance in Stroke Rehabilitation

    DEFF Research Database (Denmark)

    Hald, Kasper; Knoche, Hendrik Ole

    2016-01-01

    Abstract. This paper investigates the effect of adaptive auditory feed- back on continued player performance for stroke patients in a Whack- a-Mole style tablet game. The feedback consisted of accumulatively in- creasing the pitch of positive feedback sounds on tasks with fast reaction time...... and resetting it after slow reaction times. The analysis was based on data was obtained in a field trial with lesion patients during their regular rehabilitation. The auditory feedback events were categorized by feedback type (positive/negative) and the associated pitch change of ei- ther high or low magnitude...

  4. Ring a bell? Adaptive Auditory Game Feedback to Sustain Performance in Stroke Rehabilitation

    DEFF Research Database (Denmark)

    Hald, Kasper; Knoche, Hendrik

    2016-01-01

    This paper investigates the effect of adaptive auditory feed- back on continued player performance for stroke patients in a Whack- a-Mole style tablet game. The feedback consisted of accumulatively in- creasing the pitch of positive feedback sounds on tasks with fast reaction time and resetting...... it after slow reaction times. The analysis was based on data was obtained in a field trial with lesion patients during their regular rehabilitation. The auditory feedback events were categorized by feedback type (positive/negative) and the associated pitch change of ei- ther high or low magnitude. Both...

  5. Delayed feedback control of time-delayed chaotic systems: Analytical approach at Hopf bifurcation

    Energy Technology Data Exchange (ETDEWEB)

    Vasegh, Nastaran [Faculty of Electrical Engineering, K.N. Toosi University of Technology, PO Box 16315-1355, Tehran (Iran, Islamic Republic of)], E-mail: vasegh@eetd.kntu.ac.ir; Sedigh, Ali Khaki [Faculty of Electrical Engineering, K.N. Toosi University of Technology, PO Box 16315-1355, Tehran (Iran, Islamic Republic of)

    2008-07-28

    This Letter is concerned with bifurcation and chaos control in scalar delayed differential equations with delay parameter {tau}. By linear stability analysis, the conditions under which a sequence of Hopf bifurcation occurs at the equilibrium points are obtained. The delayed feedback controller is used to stabilize unstable periodic orbits. To find the controller delay, it is chosen such that the Hopf bifurcation remains unchanged. Also, the controller feedback gain is determined such that the corresponding unstable periodic orbit becomes stable. Numerical simulations are used to verify the analytical results.

  6. Role of auditory feedback in speech produced by cochlear implanted adults and children

    Science.gov (United States)

    Bharadwaj, Sneha V.; Tobey, Emily A.; Assmann, Peter F.; Katz, William F.

    2002-05-01

    A prominent theory of speech production proposes that speech segments are largely controlled by reference to an internal model, with minimal reliance on auditory feedback. This theory also maintains that suprasegmental aspects of speech are directly regulated by auditory feedback. Accordingly, if a talker is briefly deprived of auditory feedback speech segments should not be affected, but suprasegmental properties should show significant change. To test this prediction, comparisons were made between speech samples obtained from cochlear implant users who repeated words under two conditions (1) implant device turned ON, and (2) implant switched OFF immediately before the repetition of each word. To determine whether producing unfamiliar speech requires greater reliance on auditory feedback than producing familiar speech, English and French words were elicited from English-speaking subjects. Subjects were congenitally deaf children (n=4) and adventitiously deafened adults (n=4). Vowel fundamental frequency and formant frequencies, vowel and syllable durations, and fricative spectral moments were analyzed. Preliminary data only partially confirm the predictions, in that both segmental and suprasegmental aspects of speech were significantly modified in the absence of auditory feedback. Modifications were greater for French compared to English words, suggesting greater reliance on auditory feedback for unfamiliar words. [Work supported by NIDCD.

  7. Swing Damping for Helicopter Slung Load Systems using Delayed Feedback

    DEFF Research Database (Denmark)

    Bisgaard, Morten; la Cour-Harbo, Anders; Bendtsen, Jan Dimon

    2009-01-01

    of swing. The design of the delayed feedback controller is presented as an optimization problem which gives the possibility of an automated design process. Simulations and flight test verifications of the control system on two different autonomous helicopters are presented and it is shown how a significant......This paper presents the design and verification of a swing reducing controller for helicopter slung load systems using intentional delayed feedback. It is intended for augmenting a trajectory tracking helicopter controller and thereby improving the slung load handing capabilities for autonomous...... helicopters. The delayed feedback controller is added to actively reduce oscillations of the slung load by improving the damping of the slung load pendulum modes. Furthermore, it is intended for integration with a feedforward control scheme based on input shaping for concurrent avoidance and dampening...

  8. Predictor feedback for delay systems implementations and approximations

    CERN Document Server

    Karafyllis, Iasson

    2017-01-01

    This monograph bridges the gap between the nonlinear predictor as a concept and as a practical tool, presenting a complete theory of the application of predictor feedback to time-invariant, uncertain systems with constant input delays and/or measurement delays. It supplies several methods for generating the necessary real-time solutions to the systems’ nonlinear differential equations, which the authors refer to as approximate predictors. Predictor feedback for linear time-invariant (LTI) systems is presented in Part I to provide a solid foundation on the necessary concepts, as LTI systems pose fewer technical difficulties than nonlinear systems. Part II extends all of the concepts to nonlinear time-invariant systems. Finally, Part III explores extensions of predictor feedback to systems described by integral delay equations and to discrete-time systems. The book’s core is the design of control and observer algorithms with which global stabilization, guaranteed in the previous literature with idealized (b...

  9. Control of spatially patterned synchrony with multisite delayed feedback

    OpenAIRE

    Hauptmann, C.; Omelchenko, O.; Popovych, O. V.; Maistrenko, Y.; Tass, P.A.

    2007-01-01

    We present an analytical study describing a method for the control of spatiotemporal patterns of synchrony in networks of coupled oscillators. Delayed feedback applied through a small number of electrodes effectively induces spatiotemporal dynamics at minimal stimulation intensities. Different arrangements of the delays cause different spatial patterns of synchrony, comparable to central pattern generators (CPGs), i.e., interacting clusters of oscillatory neurons producing patterned output, e...

  10. Auditory Feedback in Music Performance: The Role of Melodic Structure and Musical Skill

    Science.gov (United States)

    Pfordresher, Peter Q.

    2005-01-01

    Five experiments explored whether fluency in musical sequence production relies on matches between the contents of auditory feedback and the planned outcomes of actions. Participants performed short melodies from memory on a keyboard while musical pitches that sounded in synchrony with each keypress (feedback contents) were altered. Results…

  11. Multivoxel Patterns Reveal Functionally Differentiated Networks Underlying Auditory Feedback Processing of Speech

    DEFF Research Database (Denmark)

    Zheng, Zane Z.; Vicente-Grabovetsky, Alejandro; MacDonald, Ewen N.

    2013-01-01

    within a multivoxel pattern analysis framework, that this sensorimotor process is supported by functionally differentiated brain networks. During scanning, a real-time speech-tracking system was used to deliver two acoustically different types of distorted auditory feedback or unaltered feedback while...

  12. A temporal predictive code for voice motor control: Evidence from ERP and behavioral responses to pitch-shifted auditory feedback.

    Science.gov (United States)

    Behroozmand, Roozbeh; Sangtian, Stacey; Korzyukov, Oleg; Larson, Charles R

    2016-04-01

    The predictive coding model suggests that voice motor control is regulated by a process in which the mismatch (error) between feedforward predictions and sensory feedback is detected and used to correct vocal motor behavior. In this study, we investigated how predictions about timing of pitch perturbations in voice auditory feedback would modulate ERP and behavioral responses during vocal production. We designed six counterbalanced blocks in which a +100 cents pitch-shift stimulus perturbed voice auditory feedback during vowel sound vocalizations. In three blocks, there was a fixed delay (500, 750 or 1000 ms) between voice and pitch-shift stimulus onset (predictable), whereas in the other three blocks, stimulus onset delay was randomized between 500, 750 and 1000 ms (unpredictable). We found that subjects produced compensatory (opposing) vocal responses that started at 80 ms after the onset of the unpredictable stimuli. However, for predictable stimuli, subjects initiated vocal responses at 20 ms before and followed the direction of pitch shifts in voice feedback. Analysis of ERPs showed that the amplitudes of the N1 and P2 components were significantly reduced in response to predictable compared with unpredictable stimuli. These findings indicate that predictions about temporal features of sensory feedback can modulate vocal motor behavior. In the context of the predictive coding model, temporally-predictable stimuli are learned and reinforced by the internal feedforward system, and as indexed by the ERP suppression, the sensory feedback contribution is reduced for their processing. These findings provide new insights into the neural mechanisms of vocal production and motor control.

  13. Nonlinear dynamics of a microelectromechanical oscillator with delayed feedback

    NARCIS (Netherlands)

    Van Leeuwen, R.; Karabacak, D.M.; Van der Zant, H.S.J.; Venstra, W.J.

    2013-01-01

    We study the dynamics of a nonlinear electromechanical oscillator with delayed feedback. Compared to their linear counterparts, we find that the dynamics is dramatically different. The well-known Barkhausen stability criterion ceases to exist, and two modes of operation emerge: one characterized by

  14. Controlling Beam Halo-Chaos via Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; WENG Jia-Qiang; ZHU Lun-Wu; LUO Xiao-Shu

    2004-01-01

    The study of controlling high-current proton beam halo-chaos has become a key concerned issue for many important applications. In this paper, time-delayed feedback control method is proposed for beam halo-chaos. Particle in cell simulation results show that the method is very effective and has some advantages for high-current beam experiments and engineering.

  15. Limit-cycle oscillators subject to a delayed feedback

    NARCIS (Netherlands)

    Erneux, T.; Grasman, J.

    2008-01-01

    The coexistence of two stable limit cycles exhibiting different periods is examined for a nonlinear oscillator subject to a delayed feedback. For the case of a weakly nonlinear oscillator, we discuss the validity of a previously determined phase equation. For the case of a strongly nonlinear oscilla

  16. Effect of auditory feedback differs according to side of hemiparesis: a comparative pilot study

    Directory of Open Access Journals (Sweden)

    Bensmail Djamel

    2009-12-01

    Full Text Available Abstract Background Following stroke, patients frequently demonstrate loss of motor control and function and altered kinematic parameters of reaching movements. Feedback is an essential component of rehabilitation and auditory feedback of kinematic parameters may be a useful tool for rehabilitation of reaching movements at the impairment level. The aim of this study was to investigate the effect of 2 types of auditory feedback on the kinematics of reaching movements in hemiparetic stroke patients and to compare differences between patients with right (RHD and left hemisphere damage (LHD. Methods 10 healthy controls, 8 stroke patients with LHD and 8 with RHD were included. Patient groups had similar levels of upper limb function. Two types of auditory feedback (spatial and simple were developed and provided online during reaching movements to 9 targets in the workspace. Kinematics of the upper limb were recorded with an electromagnetic system. Kinematics were compared between groups (Mann Whitney test and the effect of auditory feedback on kinematics was tested within each patient group (Friedman test. Results In the patient groups, peak hand velocity was lower, the number of velocity peaks was higher and movements were more curved than in the healthy group. Despite having a similar clinical level, kinematics differed between LHD and RHD groups. Peak velocity was similar but LHD patients had fewer velocity peaks and less curved movements than RHD patients. The addition of auditory feedback improved the curvature index in patients with RHD and deteriorated peak velocity, the number of velocity peaks and curvature index in LHD patients. No difference between types of feedback was found in either patient group. Conclusion In stroke patients, side of lesion should be considered when examining arm reaching kinematics. Further studies are necessary to evaluate differences in responses to auditory feedback between patients with lesions in opposite

  17. Categorical vowel perception enhances the effectiveness and generalization of auditory feedback in human-machine-interfaces.

    Directory of Open Access Journals (Sweden)

    Eric Larson

    Full Text Available Human-machine interface (HMI designs offer the possibility of improving quality of life for patient populations as well as augmenting normal user function. Despite pragmatic benefits, utilizing auditory feedback for HMI control remains underutilized, in part due to observed limitations in effectiveness. The goal of this study was to determine the extent to which categorical speech perception could be used to improve an auditory HMI. Using surface electromyography, 24 healthy speakers of American English participated in 4 sessions to learn to control an HMI using auditory feedback (provided via vowel synthesis. Participants trained on 3 targets in sessions 1-3 and were tested on 3 novel targets in session 4. An "established categories with text cues" group of eight participants were trained and tested on auditory targets corresponding to standard American English vowels using auditory and text target cues. An "established categories without text cues" group of eight participants were trained and tested on the same targets using only auditory cuing of target vowel identity. A "new categories" group of eight participants were trained and tested on targets that corresponded to vowel-like sounds not part of American English. Analyses of user performance revealed significant effects of session and group (established categories groups and the new categories group, and a trend for an interaction between session and group. Results suggest that auditory feedback can be effectively used for HMI operation when paired with established categorical (native vowel targets with an unambiguous cue.

  18. Vocal responses to perturbations in voice auditory feedback in individuals with Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Hanjun Liu

    Full Text Available BACKGROUND: One of the most common symptoms of speech deficits in individuals with Parkinson's disease (PD is significantly reduced vocal loudness and pitch range. The present study investigated whether abnormal vocalizations in individuals with PD are related to sensory processing of voice auditory feedback. Perturbations in loudness or pitch of voice auditory feedback are known to elicit short latency, compensatory responses in voice amplitude or fundamental frequency. METHODOLOGY/PRINCIPAL FINDINGS: Twelve individuals with Parkinson's disease and 13 age- and sex-matched healthy control subjects sustained a vowel sound (/α/ and received unexpected, brief (200 ms perturbations in voice loudness (±3 or 6 dB or pitch (±100 cents auditory feedback. Results showed that, while all subjects produced compensatory responses in their voice amplitude or fundamental frequency, individuals with PD exhibited larger response magnitudes than the control subjects. Furthermore, for loudness-shifted feedback, upward stimuli resulted in shorter response latencies than downward stimuli in the control subjects but not in individuals with PD. CONCLUSIONS/SIGNIFICANCE: The larger response magnitudes in individuals with PD compared with the control subjects suggest that processing of voice auditory feedback is abnormal in PD. Although the precise mechanisms of the voice feedback processing are unknown, results of this study suggest that abnormal voice control in individuals with PD may be related to dysfunctional mechanisms of error detection or correction in sensory feedback processing.

  19. Comparisons of Stuttering Frequency during and after Speech Initiation in Unaltered Feedback, Altered Auditory Feedback and Choral Speech Conditions

    Science.gov (United States)

    Saltuklaroglu, Tim; Kalinowski, Joseph; Robbins, Mary; Crawcour, Stephen; Bowers, Andrew

    2009-01-01

    Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate…

  20. Comparisons of Stuttering Frequency during and after Speech Initiation in Unaltered Feedback, Altered Auditory Feedback and Choral Speech Conditions

    Science.gov (United States)

    Saltuklaroglu, Tim; Kalinowski, Joseph; Robbins, Mary; Crawcour, Stephen; Bowers, Andrew

    2009-01-01

    Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate…

  1. Tap Arduino: An Arduino microcontroller for low-latency auditory feedback in sensorimotor synchronization experiments.

    Science.gov (United States)

    Schultz, Benjamin G; van Vugt, Floris T

    2016-12-01

    Timing abilities are often measured by having participants tap their finger along with a metronome and presenting tap-triggered auditory feedback. These experiments predominantly use electronic percussion pads combined with software (e.g., FTAP or Max/MSP) that records responses and delivers auditory feedback. However, these setups involve unknown latencies between tap onset and auditory feedback and can sometimes miss responses or record multiple, superfluous responses for a single tap. These issues may distort measurements of tapping performance or affect the performance of the individual. We present an alternative setup using an Arduino microcontroller that addresses these issues and delivers low-latency auditory feedback. We validated our setup by having participants (N = 6) tap on a force-sensitive resistor pad connected to the Arduino and on an electronic percussion pad with various levels of force and tempi. The Arduino delivered auditory feedback through a pulse-width modulation (PWM) pin connected to a headphone jack or a wave shield component. The Arduino's PWM (M = 0.6 ms, SD = 0.3) and wave shield (M = 2.6 ms, SD = 0.3) demonstrated significantly lower auditory feedback latencies than the percussion pad (M = 9.1 ms, SD = 2.0), FTAP (M = 14.6 ms, SD = 2.8), and Max/MSP (M = 15.8 ms, SD = 3.4). The PWM and wave shield latencies were also significantly less variable than those from FTAP and Max/MSP. The Arduino missed significantly fewer taps, and recorded fewer superfluous responses, than the percussion pad. The Arduino captured all responses, whereas at lower tapping forces, the percussion pad missed more taps. Regardless of tapping force, the Arduino outperformed the percussion pad. Overall, the Arduino is a high-precision, low-latency, portable, and affordable tool for auditory experiments.

  2. Controlling a time-delay system using multiple delay feedback control

    Institute of Scientific and Technical Information of China (English)

    Qi Wei; Zhang Yan; Wang Ying-Hai

    2007-01-01

    In this paper multiple delay feedback control (MDFC) with different and independent delay times is shown to be an efficient method for stabilizing fixed points in finite-dimensional dynamical systems. Whether MDFC can be applied to infinite-dimensional systems has been an open question. In this paper we find that for infinite-dimensional systems modelled by delay differential equations, MDFC works well for stabilizing (unstable) steady states in long-, moderate-and short-time delay regions, in particular for the hyperchaotic case.

  3. Combined mirror visual and auditory feedback therapy for upper limb phantom pain: a case report

    Directory of Open Access Journals (Sweden)

    Yan Kun

    2011-01-01

    Full Text Available Abstract Introduction Phantom limb sensation and phantom limb pain is a very common issue after amputations. In recent years there has been accumulating data implicating 'mirror visual feedback' or 'mirror therapy' as helpful in the treatment of phantom limb sensation and phantom limb pain. Case presentation We present the case of a 24-year-old Caucasian man, a left upper limb amputee, treated with mirror visual feedback combined with auditory feedback with improved pain relief. Conclusion This case may suggest that auditory feedback might enhance the effectiveness of mirror visual feedback and serve as a valuable addition to the complex multi-sensory processing of body perception in patients who are amputees.

  4. Adaptive modification of the delayed feedback control algorithm with a continuously varying time delay

    Energy Technology Data Exchange (ETDEWEB)

    Pyragas, V. [Semiconductor Physics Institute, Center for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania); Pyragas, K. [Semiconductor Physics Institute, Center for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

    2011-10-24

    We propose a simple adaptive delayed feedback control algorithm for stabilization of unstable periodic orbits with unknown periods. The state dependent time delay is varied continuously towards the period of controlled orbit according to a gradient-descent method realized through three simple ordinary differential equations. We demonstrate the efficiency of the algorithm with the Roessler and Mackey-Glass chaotic systems. The stability of the controlled orbits is proven by computation of the Lyapunov exponents of linearized equations. -- Highlights: → A simple adaptive modification of the delayed feedback control algorithm is proposed. → It enables the control of unstable periodic orbits with unknown periods. → The delay time is varied continuously according to a gradient descend method. → The algorithm is embodied by three simple ordinary differential equations. → The validity of the algorithm is proven by computation of the Lyapunov exponents.

  5. Logistic map with a delayed feedback: Stability of a discrete time-delay control of chaos.

    Science.gov (United States)

    Buchner, T; Zebrowski, J J

    2001-01-01

    The logistic map with a delayed feedback is studied as a generic model. The stability of the model and its bifurcation scheme is analyzed as a function of the feedback amplitude and of the delay. Stability analysis is performed semianalytically. A relation between the delay and the periodicity of the orbit, which explains why some terms used in chaos control are ineffective, was found. The consequences for chaos control are discussed. The structure of bifurcations is found to depend strongly on the parity and on the length of the delay. Boundary crisis, the tangent, the Neimark, as well as the period-doubling bifurcations occur in this system. The effective dimension of the model is also discussed.

  6. Different auditory feedback control for echolocation and communication in horseshoe bats.

    Directory of Open Access Journals (Sweden)

    Ying Liu

    Full Text Available Auditory feedback from the animal's own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Auditory feedback seems also necessary for controlling many bat communication calls, although it remains unclear how auditory feedback control differs in echolocation and communication. We tackled this question by analyzing echolocation and communication in greater horseshoe bats, whose echolocation pulses are dominated by a constant frequency component that matches the frequency range they hear best. To maintain echoes within this "auditory fovea", horseshoe bats constantly adjust their echolocation call frequency depending on the frequency of the returning echo signal. This Doppler-shift compensation (DSC behavior represents one of the most precise forms of sensory-motor feedback known. We examined the variability of echolocation pulses emitted at rest (resting frequencies, RFs and one type of communication signal which resembles an echolocation pulse but is much shorter (short constant frequency communication calls, SCFs and produced only during social interactions. We found that while RFs varied from day to day, corroborating earlier studies in other constant frequency bats, SCF-frequencies remained unchanged. In addition, RFs overlapped for some bats whereas SCF-frequencies were always distinctly different. This indicates that auditory feedback during echolocation changed with varying RFs but remained constant or may have been absent during emission of SCF calls for communication. This fundamentally different feedback mechanism for echolocation and communication may have enabled these bats to use SCF calls for individual recognition whereas they adjusted RF calls to accommodate the daily shifts of their auditory fovea.

  7. Attentional demands influence vocal compensations to pitch errors heard in auditory feedback.

    Directory of Open Access Journals (Sweden)

    Anupreet K Tumber

    Full Text Available Auditory feedback is required to maintain fluent speech. At present, it is unclear how attention modulates auditory feedback processing during ongoing speech. In this event-related potential (ERP study, participants vocalized/a/, while they heard their vocal pitch suddenly shifted downward a ½ semitone in both single and dual-task conditions. During the single-task condition participants passively viewed a visual stream for cues to start and stop vocalizing. In the dual-task condition, participants vocalized while they identified target stimuli in a visual stream of letters. The presentation rate of the visual stimuli was manipulated in the dual-task condition in order to produce a low, intermediate, and high attentional load. Visual target identification accuracy was lowest in the high attentional load condition, indicating that attentional load was successfully manipulated. Results further showed that participants who were exposed to the single-task condition, prior to the dual-task condition, produced larger vocal compensations during the single-task condition. Thus, when participants' attention was divided, less attention was available for the monitoring of their auditory feedback, resulting in smaller compensatory vocal responses. However, P1-N1-P2 ERP responses were not affected by divided attention, suggesting that the effect of attentional load was not on the auditory processing of pitch altered feedback, but instead it interfered with the integration of auditory and motor information, or motor control itself.

  8. Chaos control in delayed chaotic systems via sliding mode based delayed feedback

    Energy Technology Data Exchange (ETDEWEB)

    Vasegh, Nastaran [Faculty of Electrical Engineering, K.N. Toosi University of Technology, Seyed Khandan Bridge, Shariati St. 16314, P.O. Box 16315-1355, Tehran (Iran, Islamic Republic of)], E-mail: vasegh@eetd.kntu.ac.ir; Sedigh, Ali Khaki [Faculty of Electrical Engineering, K.N. Toosi University of Technology, Seyed Khandan Bridge, Shariati St. 16314, P.O. Box 16315-1355, Tehran (Iran, Islamic Republic of)

    2009-04-15

    This paper investigates chaos control for scalar delayed chaotic systems using sliding mode control strategy. Sliding surface design is based on delayed feedback controller. It is shown that the proposed controller can achieve stability for an arbitrary unstable fixed point (UPF) or unstable periodic orbit (UPO) with arbitrary period. The chaotic system used in this study to illustrate the theoretical concepts is the well known Mackey-Glass model. Simulation results show the effectiveness of the designed nonlinear sliding mode controller.

  9. Autonomous learning by simple dynamical systems with delayed feedback.

    Science.gov (United States)

    Kaluza, Pablo; Mikhailov, Alexander S

    2014-09-01

    A general scheme for the construction of dynamical systems able to learn generation of the desired kinds of dynamics through adjustment of their internal structure is proposed. The scheme involves intrinsic time-delayed feedback to steer the dynamics towards the target performance. As an example, a system of coupled phase oscillators, which can, by changing the weights of connections between its elements, evolve to a dynamical state with the prescribed (low or high) synchronization level, is considered and investigated.

  10. A survey on delayed feedback control of chaos

    Institute of Scientific and Technical Information of China (English)

    Yuping TIAN; Jiandong ZHU; Guanrong CHEN

    2005-01-01

    This paper introduces the basic idea and provides the mathematical formulation of the delayed feedback control (DFC) methodology, which has been widely used in chaos control. Stability analysis including the well-known odd number limitation of the DFC is reviewed. Some new developments in characterizing the limitation of the DFC are presented. Various modified DFC methods, which are developed in order to overcome the odd number limitation, are also described. Finally, some open problems in this research field are discussed.

  11. The relationship between vocal accuracy and variability to the level of compensation to altered auditory feedback.

    Science.gov (United States)

    Scheerer, Nichole E; Jones, Jeffery A

    2012-11-07

    Auditory feedback plays an important role in monitoring vocal output and determining when adjustments are necessary. In this study a group of untrained singers participated in a frequency altered feedback experiment to examine if accuracy at matching a note could predict the degree of compensation to auditory feedback that was shifted in frequency. Participants were presented with a target note and instructed to match the note in pitch and duration. Following the onset of the participants' vocalizations their vocal pitch was shifted down one semi-tone at a random time during their utterance. This altered auditory feedback was instantaneously presented back to them through headphones. Results indicated that note matching accuracy did not correlate with compensation magnitude, however, a significant correlation was found between baseline variability and compensation magnitude. These results suggest that individuals with a more stable baseline fundamental frequency rely more on feedforward control mechanisms than individuals with more variable vocal production. This increased weighting of feedforward control means they are less sensitive to mismatches between their intended vocal production and auditory feedback. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. The role of vowel perceptual cues in compensatory responses to perturbations of speech auditory feedback.

    Science.gov (United States)

    Reilly, Kevin J; Dougherty, Kathleen E

    2013-08-01

    The perturbation of acoustic features in a speaker's auditory feedback elicits rapid compensatory responses that demonstrate the importance of auditory feedback for control of speech output. The current study investigated whether responses to a perturbation of speech auditory feedback vary depending on the importance of the perturbed feature to perception of the vowel being produced. Auditory feedback of speakers' first formant frequency (F1) was shifted upward by 130 mels in randomly selected trials during the speakers' production of consonant-vowel-consonant words containing either the vowel /Λ/ or the vowel /ɝ/. Although these vowels exhibit comparable F1 frequencies, the contribution of F1 to perception of /Λ/ is greater than its contribution to perception of /ɝ/. Compensation to the F1 perturbation was observed during production of both vowels, but compensatory responses during /Λ/ occurred at significantly shorter latencies and exhibited significantly larger magnitudes than compensatory responses during /ɝ/. The finding that perturbation of vowel F1 during /Λ/ and /ɝ/ yielded compensatory differences that mirrored the contributions of F1 to perception of these vowels indicates that some portion of feedback control is weighted toward monitoring and preservation of acoustic cues for speech perception.

  13. Dynamical output feedback stabilization for neutral systems with mixed delays

    Institute of Scientific and Technical Information of China (English)

    Wei QIAN; Guo-jiang SHEN; You-xian SUN

    2008-01-01

    This paper is concerned with the issue of stabilization for the linear neutral systems with mixed delays.The attention is focused on the design of output feedback controllers which guarantee the asymptotical stability of the closed-loop systems.Based on the model transformation of neutral type,the Lyapunov-Krasovskii functional method is employed to establish the delay-dependent stability criterion.Then,through the controller parameterization and some matrix transformation techniques,the desired parameters are determined under the delay-dependent design condition in terms of linear matrix inequalities (LMIs),and the desired controller is explicitly formulated.A numerical example is given to illustrate the effectiveness of the proposed method.

  14. Relation between delayed feedback and delay-coupled systems and its application to chaotic lasers

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, Miguel C., E-mail: miguel@ifisc.uib-csic.es; Flunkert, Valentin; Fischer, Ingo [Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat Illes Balears, E-07122 Palma de Mallorca (Spain)

    2013-12-15

    We present a systematic approach to identify the similarities and differences between a chaotic system with delayed feedback and two mutually delay-coupled systems. We consider the general case in which the coupled systems are either unsynchronized or in a generally synchronized state, in contrast to the mostly studied case of identical synchronization. We construct a new time-series for each of the two coupling schemes, respectively, and present analytic evidence and numerical confirmation that these two constructed time-series are statistically equivalent. From the construction, it then follows that the distribution of time-series segments that are small compared to the overall delay in the system is independent of the value of the delay and of the coupling scheme. By focusing on numerical simulations of delay-coupled chaotic lasers, we present a practical example of our findings.

  15. Auditory display as a prosthetic hand sensory feedback for reaching and grasping tasks.

    Science.gov (United States)

    Gonzalez, Jose; Suzuki, Hiroyuki; Natsumi, Nakayama; Sekine, Masashi; Yu, Wenwei

    2012-01-01

    Upper limb amputees have to rely extensively on visual feedback in order to monitor and manipulate successfully their prosthetic device. This situation leads to high consciousness burden, which generates fatigue and frustration. Therefore, in order to enhance motor-sensory performance and awareness, an auditory display was used as a sensory feedback system for the prosthetic hand's spatio-temporal and force information in a complete reaching and grasping setting. The main objective of this study was to explore the effects of using the auditory display to monitor the prosthetic hand during a complete reaching and grasping motion. The results presented in this paper point out that the usage of an auditory display to monitor and control a robot hand improves the temporal and grasping performance greatly, while reducing mental effort and improving their confidence.

  16. Shop 'til you hear it drop - Influence of Interactive Auditory Feedback in a Virtual Reality Supermarket

    DEFF Research Database (Denmark)

    Sikström, Erik; Høeg, Emil Rosenlund; Mangano, Luca

    2016-01-01

    In this paper we describe an experiment aiming to investigate the impact of auditory feedback in a virtual reality supermarket scenario. The participants were asked to read a shopping list and collect items one by one and place them into a shopping cart. Three conditions were presented randomly, ...

  17. Auditory feedback affects perception of effort when exercising with a Pulley machine

    DEFF Research Database (Denmark)

    Bordegoni, Monica; Ferrise, Francesco; Grani, Francesco

    2013-01-01

    In this paper we describe an experiment that investigates the role of auditory feedback in affecting the perception of effort when using a physical pulley machine. Specifically, we investigated whether variations in the amplitude and frequency content of the pulley sound affect perception of effort....... Results show that variations in frequency content affect the perception of effort....

  18. On X-Channels with Feedback and Delayed CSI

    CERN Document Server

    Tandon, Ravi; Poor, H Vincent; Shamai, Shlomo

    2012-01-01

    The sum degrees of freedom (DoF) of the two-user MIMO X-channel is characterized in the presence of output feedback and delayed channel state information (CSI). The number of antennas at each transmitters is assumed to be M and the number of antennas at each of the receivers is assumed to be N. It is shown that the sum DoF of the two-user MIMO X-channel is the same as the sum DoF of a two-user MIMO broadcast channel with 2M transmit antennas, and N antennas at each receiver. Hence, for this symmetric antenna configuration, there is no performance loss in the sum degrees of freedom due to the distributed nature of the transmitters. This result highlights the usefulness of feedback and delayed CSI for the MIMO X-channel. The K-user X-channel with single antenna at each transmitter and each receiver is also studied. In this network, each transmitter has a message intended for each receiver. For this network, it is shown that the sum DoF with partial output feedback alone is at least 2K/(K+1). This lower bound is...

  19. All-optical noninvasive delayed feedback control of semiconductor lasers

    CERN Document Server

    Schikora, Sylvia

    2013-01-01

    The stabilization of unstable states hidden in the dynamics of a system, in particular the control of chaos, has received much attention in the last years. Sylvia Schikora for the first time applies a well-known control method called delayed feedback control entirely in the all-optical domain. A multisection semiconductor laser receives optical feedback from an external Fabry-Perot interferometer. The control signal is a phase-tunable superposition of the laser signal and provokes the laser to operate in an otherwise unstable periodic state with a period equal to the time delay. The control is noninvasive, because the reflected signal tends to zero when the target state is reached.   The work has been awarded the Carl-Ramsauer-Prize 2012.   Contents ·         All-Optical Control Setup ·         Stable States with Resonant Fabry-Perot Feedback ·         Control of an Unstable Stationary State and of Unstable Selfpulsations ·         Controlling Chaos ·         Con...

  20. Investigation of a delayed feedback controller of MEMS resonators

    KAUST Repository

    Masri, Karim M.

    2013-08-04

    Controlling mechanical systems is an important branch of mechanical engineering. Several techniques have been used to control Microelectromechanical systems (MEMS) resonators. In this paper, we study the effect of a delayed feedback controller on stabilizing MEMS resonators. A delayed feedback velocity controller is implemented through modifying the parallel plate electrostatic force used to excite the resonator into motion. A nonlinear single degree of freedom model is used to simulate the resonator response. Long time integration is used first. Then, a finite deference technique to capture periodic motion combined with the Floquet theory is used to capture the stable and unstable periodic responses. We show that applying a suitable positive gain can stabilize the MEMS resonator near or inside the instability dynamic pull in band. We also study the stability of the resonator by tracking its basins of attraction while sweeping the controller gain and the frequency of excitations. For positive delayed gains, we notice significant enhancement in the safe area of the basins of attraction. Copyright © 2013 by ASME.

  1. Attentional demands modulate sensorimotor learning induced by persistent exposure to changes in auditory feedback.

    Science.gov (United States)

    Scheerer, Nichole E; Tumber, Anupreet K; Jones, Jeffery A

    2016-02-01

    Hearing one's own voice is important for regulating ongoing speech and for mapping speech sounds onto articulator movements. However, it is currently unknown whether attention mediates changes in the relationship between motor commands and their acoustic output, which are necessary as growth and aging inevitably cause changes to the vocal tract. In this study, participants produced vocalizations while they heard their vocal pitch persistently shifted downward one semitone in both single- and dual-task conditions. During the single-task condition, participants vocalized while passively viewing a visual stream. During the dual-task condition, participants vocalized while also monitoring a visual stream for target letters, forcing participants to divide their attention. Participants' vocal pitch was measured across each vocalization, to index the extent to which their ongoing vocalization was modified as a result of the deviant auditory feedback. Smaller compensatory responses were recorded during the dual-task condition, suggesting that divided attention interfered with the use of auditory feedback for the regulation of ongoing vocalizations. Participants' vocal pitch was also measured at the beginning of each vocalization, before auditory feedback was available, to assess the extent to which the deviant auditory feedback was used to modify subsequent speech motor commands. Smaller changes in vocal pitch at vocalization onset were recorded during the dual-task condition, suggesting that divided attention diminished sensorimotor learning. Together, the results of this study suggest that attention is required for the speech motor control system to make optimal use of auditory feedback for the regulation and planning of speech motor commands.

  2. Effect of Training and Level of External Auditory Feedback on the Singing Voice: Pitch Inaccuracy.

    Science.gov (United States)

    Bottalico, Pasquale; Graetzer, Simone; Hunter, Eric J

    2017-01-01

    One of the most important aspects of singing is the control of fundamental frequency. The effects on pitch inaccuracy, defined as the distance in cents in equally tempered tuning between the reference note and the sung note, of the following conditions were evaluated: (1) level of external feedback, (2) tempo (slow or fast), (3) articulation (legato or staccato), (4) tessitura (low, medium, or high), and (5) semi-phrase direction (ascending or descending). The subjects were 10 nonprofessional singers and 10 classically trained professional or semi-professional singers (10 men and 10 women). Subjects sang one octave and a fifth arpeggi with three different levels of external auditory feedback, two tempi, and two articulations (legato or staccato). It was observed that inaccuracy was greatest in the descending semi-phrase arpeggi produced at a fast tempo and with a staccato articulation, especially for nonprofessional singers. The magnitude of inaccuracy was also relatively large in the high tessitura relative to the low and the medium tessitura for such singers. Contrary to predictions, when external auditory feedback was strongly attenuated by the hearing protectors, nonprofessional singers showed greater pitch accuracy than in the other external feedback conditions. This finding indicates the importance of internal auditory feedback in pitch control. With an increase in training, the singer's pitch inaccuracy decreases. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  3. Hopf Bifurcation of a Positive Feedback Delay Differential Equation

    Institute of Scientific and Technical Information of China (English)

    陈玉明; 黄立宏

    2003-01-01

    Under some minor technical hypotheses, for each T larger than a certain Ts > 0, Krisztin, Walther and Wu showed the existence of a periodic orbit for the positive feedback delay differential equation x(t) =-Tμx(t) +Tf(x(t - 1)), where T and μ are positive constants and f : R→ R satisfies f(0) = 0 and f′ > 0 。Combining this with a unique result of Krisztin and Walther, we know that this periodic orbit is the one branched out from 0 through Hopf bifurcation. Using the normal form theory for delay differential equations, we show the same result underthe condition that f ∈ C3(R,R) is such that f″(0) = 0 and f″′(0) < 0, which is weaker than those of Krisztin and Walther。

  4. The experience of agency in sequence production with altered auditory feedback.

    Science.gov (United States)

    Couchman, Justin J; Beasley, Robertson; Pfordresher, Peter Q

    2012-03-01

    When speaking or producing music, people rely in part on auditory feedback - the sounds associated with the performed action. Three experiments investigated the degree to which alterations of auditory feedback (AAF) during music performances influence the experience of agency (i.e., the sense that your actions led to auditory events) and the possible link between agency and the disruptive effect of AAF on production. Participants performed short novel melodies from memory on a keyboard. Auditory feedback during performances was manipulated with respect to its pitch contents and/or its synchrony with actions. Participants rated their experience of agency after each trial. In all experiments, AAF reduced judgments of agency across conditions. Performance was most disrupted (measured by error rates and slowing) when AAF led to an ambiguous experience of agency, suggesting that there may be some causal relationship between agency and disruption. However, analyses revealed that these two effects were probably independent. A control experiment verified that performers can make veridical judgments of agency. Published by Elsevier Inc.

  5. Time-delayed quantum coherent Pyragas feedback control of photon squeezing in a degenerate parametric oscillator

    Science.gov (United States)

    Kraft, Manuel; Hein, Sven M.; Lehnert, Judith; Schöll, Eckehard; Hughes, Stephen; Knorr, Andreas

    2016-08-01

    Quantum coherent feedback control is a measurement-free control method fully preserving quantum coherence. In this paper we show how time-delayed quantum coherent feedback can be used to control the degree of squeezing in the output field of a cavity containing a degenerate parametric oscillator. We focus on the specific situation of Pyragas-type feedback control where time-delayed signals are fed back directly into the quantum system. Our results show how time-delayed feedback can enhance or decrease the degree of squeezing as a function of time delay and feedback strength.

  6. The effect of visual feedback and training in auditory-perceptual judgment of voice quality.

    Science.gov (United States)

    Barsties, Ben; Beers, Mieke; Ten Cate, Liesbeth; Van Ballegooijen, Karin; Braam, Lilian; De Groot, Merel; Van Der Kant, Marieke; Kruitwagen, Cas; Maryn, Youri

    2017-04-01

    The aim of the present investigation was to evaluate the effect of visual feedback on rating voice quality severity level and the reliability of voice quality judgment by inexperienced listeners. For this purpose two training programs were created, each lasting 2 hours. In total 37 undergraduate speech-language therapy students participated in the study and were divided into a visual plus auditory-perceptual feedback group (V + AF), an auditory-perceptual feedback group (AF), and a control group with no feedback (NF). All listeners completed two rating sessions judging overall severity labeled as grade (G), roughness (R), and breathiness (B). The judged voice samples contained the concatenation of continuous speech and sustained phonation. No significant rater reliability changes were found in the pre- and posttest between the three groups in every GRB-parameter (all p > 0.05). There was a training effect seen in the significant improvement of rater reliability for roughness within the NF and AF groups (all p visual and auditory anchors while rating as well as longer training sessions may be required to draw a firm conclusion.

  7. Role of Delay of Feedback on Subsequent Pattern Recognition Transfer Tasks.

    Science.gov (United States)

    Schroth, Marvin L.; Lund, Elissa

    1993-01-01

    Two experiments with 100 undergraduates investigated effects of delay of feedback on immediate and delayed transfer tasks involving different pattern recognition strategies. Delay of feedback resulted in greater retention of the concepts underlying construction of the different patterns in all transfer tasks. Results support the Kulhavy-Anderson…

  8. Stability analysis in a car-following model with reaction-time delay and delayed feedback control

    Science.gov (United States)

    Jin, Yanfei; Xu, Meng

    2016-10-01

    The delayed feedback control in terms of both headway and velocity differences has been proposed to guarantee the stability of a car-following model including the reaction-time delay of drivers. Using Laplace transformation and transfer function, the stable condition is derived and appropriate choices of time delay and feedback gains are designed to stabilize traffic flow. Meanwhile, an upper bound on explicit time delay is determined with respect to the response of desired acceleration. To ensure the string stability, the explicit time delay cannot over its upper bound. Numerical simulations indicate that the proposed control method can restraint traffic congestion and improve control performance.

  9. On the Permanence of a Nonautonomous Nicholson's Blowflies Model with Feedback Control and Delay

    Institute of Scientific and Technical Information of China (English)

    LAI Wei-ying

    2011-01-01

    A nonautonomous Nicholson's Blowflies model with feedback control and delay is investigated in this paper.We show that for this system,feedback control variable has no influence on the persistent property of the system.

  10. The Permanence in a Single Species Nonautonomous System with Delays and Feedback Control

    OpenAIRE

    2010-01-01

    We consider a single species nonautonomous system with delays and feedback control. A general criterion on the permanence for all positive solutions is established. The results show that the feedback control does not influence the permanence of species.

  11. Compensations to auditory feedback perturbations in congenitally blind and sighted speakers: Acoustic and articulatory data.

    Science.gov (United States)

    Trudeau-Fisette, Pamela; Tiede, Mark; Ménard, Lucie

    2017-01-01

    This study investigated the effects of visual deprivation on the relationship between speech perception and production by examining compensatory responses to real-time perturbations in auditory feedback. Specifically, acoustic and articulatory data were recorded while sighted and congenitally blind French speakers produced several repetitions of the vowel /ø/. At the acoustic level, blind speakers produced larger compensatory responses to altered vowels than their sighted peers. At the articulatory level, blind speakers also produced larger displacements of the upper lip, the tongue tip, and the tongue dorsum in compensatory responses. These findings suggest that blind speakers tolerate less discrepancy between actual and expected auditory feedback than sighted speakers. The study also suggests that sighted speakers have acquired more constrained somatosensory goals through the influence of visual cues perceived in face-to-face conversation, leading them to tolerate less discrepancy between expected and altered articulatory positions compared to blind speakers and thus resulting in smaller observed compensatory responses.

  12. Continuous Auditory Feedback of Eye Movements: An Exploratory Study toward Improving Oculomotor Control

    Directory of Open Access Journals (Sweden)

    Eric O. Boyer

    2017-04-01

    Full Text Available As eye movements are mostly automatic and overtly generated to attain visual goals, individuals have a poor metacognitive knowledge of their own eye movements. We present an exploratory study on the effects of real-time continuous auditory feedback generated by eye movements. We considered both a tracking task and a production task where smooth pursuit eye movements (SPEM can be endogenously generated. In particular, we used a visual paradigm which enables to generate and control SPEM in the absence of a moving visual target. We investigated whether real-time auditory feedback of eye movement dynamics might improve learning in both tasks, through a training protocol over 8 days. The results indicate that real-time sonification of eye movements can actually modify the oculomotor behavior, and reinforce intrinsic oculomotor perception. Nevertheless, large inter-individual differences were observed preventing us from reaching a strong conclusion on sensorimotor learning improvements.

  13. A Bayesian Account of Vocal Adaptation to Pitch-Shifted Auditory Feedback

    Science.gov (United States)

    Hahnloser, Richard H. R.

    2017-01-01

    Motor systems are highly adaptive. Both birds and humans compensate for synthetically induced shifts in the pitch (fundamental frequency) of auditory feedback stemming from their vocalizations. Pitch-shift compensation is partial in the sense that large shifts lead to smaller relative compensatory adjustments of vocal pitch than small shifts. Also, compensation is larger in subjects with high motor variability. To formulate a mechanistic description of these findings, we adapt a Bayesian model of error relevance. We assume that vocal-auditory feedback loops in the brain cope optimally with known sensory and motor variability. Based on measurements of motor variability, optimal compensatory responses in our model provide accurate fits to published experimental data. Optimal compensation correctly predicts sensory acuity, which has been estimated in psychophysical experiments as just-noticeable pitch differences. Our model extends the utility of Bayesian approaches to adaptive vocal behaviors. PMID:28135267

  14. Experimental study of delayed positive feedback control for a flexible beam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing ...

  15. Cochlear Delay and Medial Olivocochlear Functioning in Children with Suspected Auditory Processing Disorder.

    Directory of Open Access Journals (Sweden)

    Sriram Boothalingam

    Full Text Available Behavioral manifestations of processing deficits associated with auditory processing disorder (APD have been well documented. However, little is known about their anatomical underpinnings, especially cochlear processing. Cochlear delays, a proxy for cochlear tuning, measured using stimulus frequency otoacoustic emission (SFOAE group delay, and the influence of the medial olivocochlear (MOC system activation at the auditory periphery was studied in 23 children suspected with APD (sAPD and 22 typically developing (TD children. Results suggest that children suspected with APD have longer SFOAE group delays (possibly due to sharper cochlear tuning and reduced MOC function compared to TD children. Other differences between the groups include correlation between MOC function and SFOAE delay in quiet in the TD group, and lack thereof in the sAPD group. MOC-mediated changes in SFOAE delay were in opposite directions between groups: increase in delay in TD vs. reduction in delay in the sAPD group. Longer SFOAE group delays in the sAPD group may lead to longer cochlear filter ringing, and potential increase in forward masking. These results indicate differences in cochlear and MOC function between sAPD and TD groups. Further studies are warranted to explore the possibility of cochlea as a potential site for processing deficits in APD.

  16. Delayed-feedback chimera states: Forced multiclusters and stochastic resonance

    Science.gov (United States)

    Semenov, V.; Zakharova, A.; Maistrenko, Y.; Schöll, E.

    2016-07-01

    A nonlinear oscillator model with negative time-delayed feedback is studied numerically under external deterministic and stochastic forcing. It is found that in the unforced system complex partial synchronization patterns like chimera states as well as salt-and-pepper-like solitary states arise on the route from regular dynamics to spatio-temporal chaos. The control of the dynamics by external periodic forcing is demonstrated by numerical simulations. It is shown that one-cluster and multi-cluster chimeras can be achieved by adjusting the external forcing frequency to appropriate resonance conditions. If a stochastic component is superimposed to the deterministic external forcing, chimera states can be induced in a way similar to stochastic resonance, they appear, therefore, in regimes where they do not exist without noise.

  17. Coherence versus reliability of stochastic oscillators with delayed feedback.

    Science.gov (United States)

    Goldobin, Denis S

    2008-12-01

    For noisy self-sustained oscillators, both reliability, the stability of a response to a noisy driving, and coherence, understood in the sense of constancy of oscillation frequency, are important characteristics. Although both characteristics and techniques for controlling them have received great attention from researchers, owing to their importance for neurons, lasers, clocks, electric generators, etc., these characteristics were previously considered separately. In this paper, a strong quantitative relation between coherence and reliability is revealed for a limit cycle oscillator subject to a weak noisy driving and a linear delayed feedback, a convection control tool. The analytical findings are verified and enriched with a numerical simulation for the Van der Pol-Duffing oscillator.

  18. On the Role of Auditory Feedback in Robot-Assisted Movement Training after Stroke: Review of the Literature

    Directory of Open Access Journals (Sweden)

    Giulio Rosati

    2013-01-01

    reviewed. In particular, a comparative quantitative analysis over a large corpus of the recent literature suggests that the potential of auditory feedback in rehabilitation systems is currently and largely underexploited. Finally, several scenarios are proposed in which the use of auditory feedback may contribute to overcome some of the main limitations of current rehabilitation systems, in terms of user engagement, development of acute-phase and home rehabilitation devices, learning of more complex motor tasks, and improving activities of daily living.

  19. Output regulation problem for discrete-time linear time-delay systems by output feedback control

    Institute of Scientific and Technical Information of China (English)

    Yamin YAN; Jie HUANG

    2016-01-01

    In this paper, we study the output regulation problem of discrete linear time-delay systems by output feedback control. We have established some results parallel to those for the output regulation problem of continuous linear time-delay systems.

  20. Delayed feedback control of unstable steady states in fractional-order chaotic systems

    CERN Document Server

    Gjurchinovski, Aleksandar; Urumov, Viktor

    2010-01-01

    We study the possibility to stabilize unstable steady states in chaotic fractional-order dynamical systems by the time-delayed feedback method with both constant and time-varying delays. By performing a linear stability analysis in the constant delay case, we establish the parameter ranges for successful stabilization of unstable equilibria in the plane parametrizad by the feedback gain and the time delay. An insight into the control mechanism is gained by analyzing the characteristic equation of the controlled system, showing that the control scheme fails to control unstable equilibria having an odd number of positive real eigenvalues. It is shown numerically that delayed feedback control with a variable time-delay significantly enlarges the stability region of the steady states in comparison to the classical time-delayed feedback scheme with a constant delay.

  1. The effect of process delay on dynamical behaviors in a self-feedback nonlinear oscillator

    Science.gov (United States)

    Yao, Chenggui; Ma, Jun; Li, Chuan; He, Zhiwei

    2016-10-01

    The delayed feedback loops play a crucial role in the stability of dynamical systems. The effect of process delay in feedback is studied numerically and theoretically in the delayed feedback nonlinear systems including the neural model, periodic system and chaotic oscillator. The process delay is of key importance in determining the evolution of systems, and the rich dynamical phenomena are observed. By introducing a process delay, we find that it can induce bursting electric activities in the neural model. We demonstrate that this novel regime of amplitude death also exists in the parameter space of feedback strength and process delay for the periodic system and chaotic oscillator. Our results extend the effect of process delay in the paper of Zou et al.(2013) where the process delay can eliminate the amplitude death of the coupled nonlinear systems.

  2. Synthesis for robust synchronization of chaotic systems under output feedback control with multiple random delays

    Energy Technology Data Exchange (ETDEWEB)

    Wen Guilin [Key Laboratory of Advanced Technology for Vehicle Body Design and Manufactory, M.O.E, College of Mechanical and Automotive Engineering, Hunan University, Changsha, Hunan 410082 (China); Wang Qingguo [Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore)]. E-mail: elewqg@nus.edu.sg; Lin Chong [Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Han Xu [Key Laboratory of Advanced Technology for Vehicle Body Design and Manufactory, M.O.E, College of Mechanical and Automotive Engineering, Hunan University, Changsha, Hunan 410082 (China); Li Guangyao [Key Laboratory of Advanced Technology for Vehicle Body Design and Manufactory, M.O.E, College of Mechanical and Automotive Engineering, Hunan University, Changsha, Hunan 410082 (China)

    2006-09-15

    Synchronization under output feedback control with multiple random time delays is studied, using the paradigm in nonlinear physics-Chua's circuit. Compared with other synchronization control methods, output feedback control with multiple random delay is superior for a realistic synchronization application to secure communications. Sufficient condition for global stability of delay-dependent synchronization is established based on the LMI technique. Numerical simulations fully support the analytical approach, in spite of the random delays.

  3. Delay signatures in the chaotic intensity output of a quantum dot laser with optical feedback

    Indian Academy of Sciences (India)

    VARGHESE BEJOY; JOHN MANU P; NANDAKUMARAN V M

    2016-05-01

    Delay identification from the chaotic intensity output of a quantum dot laser with optical feedback is done using numerical and information theoretic techniques. Four quantifiers, namely autocorrelation function, delayed mutual information, permutation entropy and permutation statistical complexity, are employed in delay estimation. A detailed comparison of these quantifiers with different feedback rates and delay is undertaken. Permutation entropy and permutation statistical complexity are calculated with different dimensions of symbolic reconstruction to obtain the best results.

  4. Dynamical behaviors in time-delay systems with delayed feedback and digitized coupling

    Science.gov (United States)

    Mitra, Chiranjit; Ambika, G.; Banerjee, Soumitro

    2014-12-01

    We consider a network of delay dynamical systems connected in a ring via unidirectional positive feedback with constant delay in coupling. For the specific case of Mackey-Glass systems on the ring topology, we capture the phenomena of amplitude death, isochronous synchronization and phase-flip bifurcation as the relevant parameters are tuned. Using linear stability analysis and master stability function approach, we predict the region of amplitude death and synchronized states respectively in the parameter space and study the nature of transitions between the different states. For a large number of systems in the same dynamical configuration, we observe splay states, mixed splay states and phase locked clusters. We extend the study to the case of digitized coupling and observe that these emergent states still persist. However, the sampling and quantization reduce the regions of amplitude death and induce phase-flip bifurcation.

  5. Timing matters: the impact of immediate and delayed feedback on artificial language learning.

    Science.gov (United States)

    Opitz, Bertram; Ferdinand, Nicola K; Mecklinger, Axel

    2011-01-01

    In the present experiment, we used event-related potentials (ERP) to investigate the role of immediate and delayed feedback in an artificial grammar learning (AGL) task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of 1 s. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP) elicited by positive feedback only. The feedback-related negativity (FRN), however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for AGL as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.

  6. Timing matters: The impact of immediate and delayed feedback on artificial language learning

    Directory of Open Access Journals (Sweden)

    Bertram Opitz

    2011-02-01

    Full Text Available In the present experiment, we used event-related potentials (ERP to investigate the role of immediate and delayed feedback in an artificial grammar learning task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of one second. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP elicited by positive feedback only. The feedback-related negativity (FRN, however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for artificial grammar learning as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.

  7. Chaos and Its Impulsive Control in Chua's Oscillator via Time-Delay Feedback

    Institute of Scientific and Technical Information of China (English)

    Yong-Bin Yu; Hong-Bin Zhang; Zhu-Sheng Kang; Xiao-Feng Liao; Jue-Bang Yu

    2008-01-01

    A novel framework for chaos and its impul sive control in Chua's oscillator via time-delay feedback is presented. The exponential stability of impulsive control Chua's oscillator via time-delay feedback is considered, and some novel conditions are obtained. Then a novel impulsive controller design procedure is proposed. Simulation experiments are provided to demonstrate the feasibility and effectiveness of our method finally.

  8. Delayed auditory conduction in diabetes: is metformin-induced vitamin B12 deficiency responsible?

    Science.gov (United States)

    Khattar, Deepti; Khaliq, Farah; Vaney, Neelam; Madhu, Sri Venkata

    2016-01-01

    Summary The present study aims to evaluate the functional integrity of the auditory pathway in patients with diabetes taking metformin. A further aim is to assess its association with vitamin B12 deficiency induced by metformin. Thirty diabetics taking metformin and 30 age-matched non-diabetic controls were enrolled. Stimulus-related potentials and vitamin B12 levels were evaluated in all the subjects. The diabetics showed deficient vitamin B12 levels and delayed wave III latency and III–V interpeak latency in the right ear and delayed Na and Pa wave latencies in the left ear compared with the controls. The dose and duration of metformin showed no association with the stimulus-related potentials. Therefore, although vitamin B12 levels were deficient and auditory conduction impairment was present in the diabetics on metformin, this impairment cannot be attributed to the vitamin B12 deficiency. PMID:27358222

  9. Two-dimensional dissipative rogue waves due to time-delayed feedback in cavity nonlinear optics

    Science.gov (United States)

    Tlidi, Mustapha; Panajotov, Krassimir

    2017-01-01

    We demonstrate a way to generate two-dimensional rogue waves in two types of broad area nonlinear optical systems subject to time-delayed feedback: in the generic Lugiato-Lefever model and in the model of a broad-area surface-emitting laser with saturable absorber. The delayed feedback is found to induce a spontaneous formation of rogue waves. In the absence of delayed feedback, spatial pulses are stationary. The rogue waves are exited and controlled by the delay feedback. We characterize their formation by computing the probability distribution of the pulse height. The long-tailed statistical contribution, which is often considered as a signature of the presence of rogue waves, appears for sufficiently strong feedback. The generality of our analysis suggests that the feedback induced instability leading to the spontaneous formation of two-dimensional rogue waves is a universal phenomenon.

  10. Delayed feedback during sensorimotor learning selectively disrupts adaptation but not strategy use.

    Science.gov (United States)

    Brudner, Samuel N; Kethidi, Nikhit; Graeupner, Damaris; Ivry, Richard B; Taylor, Jordan A

    2016-03-01

    In sensorimotor adaptation tasks, feedback delays can cause significant reductions in the rate of learning. This constraint is puzzling given that many skilled behaviors have inherently long delays (e.g., hitting a golf ball). One difference in these task domains is that adaptation is primarily driven by error-based feedback, whereas skilled performance may also rely to a large extent on outcome-based feedback. This difference suggests that error- and outcome-based feedback may engage different learning processes, and these processes may be associated with different temporal constraints. We tested this hypothesis in a visuomotor adaptation task. Error feedback was indicated by the terminal position of a cursor, while outcome feedback was indicated by points. In separate groups of participants, the two feedback signals were presented immediately at the end of the movement, after a delay, or with just the error feedback delayed. Participants learned to counter the rotation in a similar manner regardless of feedback delay. However, the aftereffect, an indicator of implicit motor adaptation, was attenuated with delayed error feedback, consistent with the hypothesis that a different learning process supports performance under delay. We tested this by employing a task that dissociates the contribution of explicit strategies and implicit adaptation. We find that explicit aiming strategies contribute to the majority of the learning curve, regardless of delay; however, implicit learning, measured over the course of learning and by aftereffects, was significantly attenuated with delayed error-based feedback. These experiments offer new insight into the temporal constraints associated with different motor learning processes.

  11. On a new time-delayed feedback control of chaotic systems

    Energy Technology Data Exchange (ETDEWEB)

    Tian Lixin [Nonlinear Scientific Research Center, Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China)], E-mail: tianlx@ujs.edu.cn; Xu Jun; Sun Mei; Li Xiuming [Nonlinear Scientific Research Center, Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China)

    2009-01-30

    In this paper, using the idea of the successive dislocation feedback method, a new time-delayed feedback control method called the successive dislocation time-delayed feedback control (SDTDFC) is designed. Firstly, the idea of SDTDFC is introduced. Then some analytic sufficient conditions of the chaos control from the SDTDFC approach are derived for stabilization. Finally, some established results are further clarified via a case study of the Lorenz system with the numerical simulations.

  12. Deriving cochlear delays in humans using otoacoustic emissions and auditory evoked potentials

    DEFF Research Database (Denmark)

    Pigasse, Gilles

    A great deal of the processing of incoming sounds to the auditory system occurs within the cochlear. The organ of Corti within the cochlea has differing mechanical properties along its length that broadly gives rise to frequency selectivity. Its stiffness is at maximum at the base and decreases...... relation between frequency and travel time in the cochlea defines the cochlear delay. This delay is directly associated with the signal analysis occurring in the inner ear and is therefore of primary interest to get a better knowledge of this organ. It is possible to estimate the cochlear delay by direct...... and ASSR latency estimates demonstrated similar rates of latency decrease as a function of frequency. It was further concluded, in this thesis, that OAE measurements are the most appropriate to estimate cochlear delays, since they had the best repeatability and the shortest recording time. Preliminary...

  13. The dynamics of second-order equations with delayed feedback and a large coefficient of delayed control

    Science.gov (United States)

    Kashchenko, Sergey A.

    2016-12-01

    The dynamics of second-order equations with nonlinear delayed feedback and a large coefficient of a delayed equation is investigated using asymptotic methods. Based on special methods of quasi-normal forms, a new construction is elaborated for obtaining the main terms of asymptotic expansions of asymptotic residual solutions. It is shown that the dynamical properties of the above equations are determined mostly by the behavior of the solutions of some special families of parabolic boundary value problems. A comparative analysis of the dynamics of equations with the delayed feedback of three types is carried out.

  14. Effect of the loss of auditory feedback on segmental parameters of vowels of postlingually deafened speakers.

    Science.gov (United States)

    Schenk, Barbara S; Baumgartner, Wolf Dieter; Hamzavi, Jafar Sasan

    2003-12-01

    The most obvious and best documented changes in speech of postlingually deafened speakers are the rate, fundamental frequency, and volume (energy). These changes are due to the lack of auditory feedback. But auditory feedback affects not only the suprasegmental parameters of speech. The aim of this study was to determine the change at the segmental level of speech in terms of vowel formants. Twenty-three postlingually deafened and 18 normally hearing speakers were recorded reading a German text. The frequencies of the first and second formants and the vowel spaces of selected vowels in word-in-context condition were compared. All first formant frequencies (F1) of the postlingually deafened speakers were significantly different from those of the normally hearing people. The values of F1 were higher for the vowels /e/ (418+/-61 Hz compared with 359+/-52 Hz, P=0.006) and /o/ (459+/-58 compared with 390+/-45 Hz, P=0.0003) and lower for /a/ (765+/-115 Hz compared with 851+/-146 Hz, P=0.038). The second formant frequency (F2) only showed a significant increase for the vowel/e/(2016+/-347 Hz compared with 2279+/-250 Hz, P=0.012). The postlingually deafened people were divided into two subgroups according to duration of deafness (shorter/longer than 10 years of deafness). There was no significant difference in formant changes between the two groups. Our report demonstrated an effect of auditory feedback also on segmental features of speech of postlingually deafened people.

  15. Theory and numerics of vibrational resonance in Duffing oscillators with time-delayed feedback.

    Science.gov (United States)

    Jeevarathinam, C; Rajasekar, S; Sanjuán, M A F

    2011-06-01

    The influence of linear time-delayed feedback on vibrational resonance is investigated in underdamped and overdamped Duffing oscillators with double-well and single-well potentials driven by both low frequency and high frequency periodic forces. This task is performed through both theoretical approach and numerical simulation. Theoretically determined values of the amplitude of the high frequency force and the delay time at which resonance occurs are in very good agreement with the numerical simulation. A major consequence of time-delayed feedback is that it gives rise to a periodic or quasiperiodic pattern of vibrational resonance profile with respect to the time-delayed parameter. An appropriate time delay is shown to induce a resonance in an overdamped single-well system which is otherwise not possible. For a range of values of the time-delayed parameters, the response amplitude is found to be larger than in delay-time feedback-free systems.

  16. Fundamental and Subharmonic Resonances of Harmonically Oscillation with Time Delay State Feedback

    Directory of Open Access Journals (Sweden)

    A.F. EL-Bassiouny

    2006-01-01

    Full Text Available Time delays occur in many physical systems. In particular, when automatic control is used with structural or mechanical systems, there exists a delay between measurement of the system state and corrective action. The concept of an equivalent damping related to the delay feedback is proposed and the appropriate choice of the feedback gains and the time delay is discussed from the viewpoint of vibration control. We investigate the fundamental resonance and subharmonic resonance of order one-half of a harmonically oscillation under state feedback control with a time delay. By using the multiple scale perturbation technique, the first order approximation of the resonances are derived and the effect of time delay on the resonances is investigated. The fixed points correspond to a periodic motion for the starting system and we show the external excitation-response and frequency-response curves. We analyze the effect of time delay and the other different parameters on these oscillations.

  17. Response of harmonically and stochastically excited strongly nonlinear oscillators with delayed feedback bang-bang control

    Institute of Scientific and Technical Information of China (English)

    Chang-shui FENG; Wei-qiu ZHU

    2009-01-01

    We studied the response of harmonically and stochastically excited strongly nonlinear oscillators with delayed feedback bang-bang control using the stochastic averaging method. First, the time-delayed feedback bang-bang control force is expressed approximately in terms of the system state variables without time delay. Then the averaged Ito stochastic differential equations for the system are derived using the stochastic averaging method. Finally, the response of the system is obtained by solving the Fokker-Plank-Kolmogorov (FPK) equation associated with the averaged Ito equations. A Duffing oscillator with time-delayed feedback bang-bang control under combined harmonic and white noise excitations is taken as an example to illus-trate the proposed method. The analytical results are confirmed by digital simulation. We found that the time delay in feedback bang-bang control will deteriorate the control effectiveness and cause bifurcation of stochastic jump of Duffing oscillator.

  18. Autaptic self-feedback-induced synchronization transitions in Newman-Watts neuronal network with time delays

    Science.gov (United States)

    Wang, Qi; Gong, Yubing; Wu, Yanan

    2015-04-01

    Autapse is a special synapse that connects a neuron to itself. In this work, we numerically study the effect of chemical autapse on the synchronization of Newman-Watts Hodgkin-Huxley neuron network with time delays. It is found that the neurons exhibit synchronization transitions as autaptic self-feedback delay is varied, and the phenomenon enhances when autaptic self-feedback strength increases. Moreover, this phenomenon becomes strongest when network time delay or coupling strength is optimal. It is also found that the synchronization transitions by network time delay can be enhanced by autaptic activity and become strongest when autaptic delay is optimal. These results show that autaptic delayed self-feedback activity can intermittently enhance and reduce the synchronization of the neuronal network and hence plays an important role in regulating the synchronization of the neurons. These findings could find potential implications for the information processing and transmission in neural systems.

  19. A new switching parameter varying optoelectronic delayed feedback model with computer simulation

    Science.gov (United States)

    Liu, Lingfeng; Miao, Suoxia; Cheng, Mengfan; Gao, Xiaojing

    2016-02-01

    In this paper, a new switching parameter varying optoelectronic delayed feedback model is proposed and analyzed by computer simulation. This model is switching between two parameter varying optoelectronic delayed feedback models based on chaotic pseudorandom sequences. Complexity performance results show that this model has a high complexity compared to the original model. Furthermore, this model can conceal the time delay effectively against the auto-correlation function, delayed mutual information and permutation information analysis methods, and can extent the key space, which greatly improve its security.

  20. Auditory feedback control of vocal pitch during sustained vocalization: a cross-sectional study of adult aging.

    Directory of Open Access Journals (Sweden)

    Peng Liu

    Full Text Available BACKGROUND: Auditory feedback has been demonstrated to play an important role in the control of voice fundamental frequency (F(0, but the mechanisms underlying the processing of auditory feedback remain poorly understood. It has been well documented that young adults can use auditory feedback to stabilize their voice F(0 by making compensatory responses to perturbations they hear in their vocal pitch feedback. However, little is known about the effects of aging on the processing of audio-vocal feedback during vocalization. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we recruited adults who were between 19 and 75 years of age and divided them into five age groups. Using a pitch-shift paradigm, the pitch of their vocal feedback was unexpectedly shifted ±50 or ±100 cents during sustained vocalization of the vowel sound/u/. Compensatory vocal F(0 response magnitudes and latencies to pitch feedback perturbations were examined. A significant effect of age was found such that response magnitudes increased with increasing age until maximal values were reached for adults 51-60 years of age and then decreased for adults 61-75 years of age. Adults 51-60 years of age were also more sensitive to the direction and magnitude of the pitch feedback perturbations compared to younger adults. CONCLUSION: These findings demonstrate that the pitch-shift reflex systematically changes across the adult lifespan. Understanding aging-related changes to the role of auditory feedback is critically important for our theoretical understanding of speech production and the clinical applications of that knowledge.

  1. Determination of Optimal Control Strength of Delayed Feedback Control Using Time Series

    Institute of Scientific and Technical Information of China (English)

    YIN Hua-Wei; LU Wei-Ping; WANG Peng-Ye

    2004-01-01

    @@ We study controlling chaos using time-delayed feedback control based on chaotic time series without prior knowl edge of dynamical systems, and determine the optimal control parameters for stabilizing unstable periodic orbits with maximal stability.

  2. Hopf bifurcation control for a class of delay differential systems with discrete-time delayed feedback controller

    Science.gov (United States)

    Su, Huan; Mao, Xuerong; Li, Wenxue

    2016-11-01

    This paper is concerned with the asymptotical stabilization for a class of unstable delay differential equations. Continuous-time delayed feedback controller (C-TDFC) and discrete-time delayed feedback controller (D-TDFC) are presented and studied, respectively. To our best knowledge, applying Hopf bifurcation theory to delay differential equations with D-TDFC is original and meaningful. The difficulty brought by the introduction of sampling period has been overcome. An effective control range which ensures the asymptotical stability of equilibrium for the system with C-TDFC is obtained. Sequently, another effective control range for the system with D-TDFC is gotten, which approximates the one of C-TDFCS provided that the sampling period is sufficiently small. Meanwhile, efforts are paid to estimate a bound on sampling period. Finally, the theoretical results are applied to a physiological system to illustrate the effectiveness of the two control ranges.

  3. Firing statistics of inhibitory neuron with delayed feedback. I. Output ISI probability density.

    Science.gov (United States)

    Vidybida, A K; Kravchuk, K G

    2013-06-01

    Activity of inhibitory neuron with delayed feedback is considered in the framework of point stochastic processes. The neuron receives excitatory input impulses from a Poisson stream, and inhibitory impulses from the feedback line with a delay. We investigate here, how does the presence of inhibitory feedback affect the output firing statistics. Using binding neuron (BN) as a model, we derive analytically the exact expressions for the output interspike intervals (ISI) probability density, mean output ISI and coefficient of variation as functions of model's parameters for the case of threshold 2. Using the leaky integrate-and-fire (LIF) model, as well as the BN model with higher thresholds, these statistical quantities are found numerically. In contrast to the previously studied situation of no feedback, the ISI probability densities found here both for BN and LIF neuron become bimodal and have discontinuity of jump type. Nevertheless, the presence of inhibitory delayed feedback was not found to affect substantially the output ISI coefficient of variation. The ISI coefficient of variation found ranges between 0.5 and 1. It is concluded that introduction of delayed inhibitory feedback can radically change neuronal output firing statistics. This statistics is as well distinct from what was found previously (Vidybida and Kravchuk, 2009) by a similar method for excitatory neuron with delayed feedback.

  4. ON THE PERSISTENT PROPERTY OF A DELAYED NON-AUTONOMOUS SCHOENER MODEL WITH FEEDBACK CONTROL

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    We study a delayed non-autonomous Schoener model with feedback control, which was proposed by Qiming Liu, Rui Xu and Pinghua Yang [8]. By applying a differential inequality and some analysis technique, we show that under some suitable assumptions, the feedback control variable has no influence on the persistent property of the system. Our result improves the existing ones.

  5. PERMANENCE OF A DISCRETE SINGLE SPECIES SYSTEM WITH DELAYS AND FEEDBACK CONTROL

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this paper,a discrete single species system with time delays and feedback control is considered.Sufficient conditions which guarantee the permanence of all positive solutions to this discrete system are obtained.The results show that the feedback control is harmless for the permanence of the species.

  6. Permanence of a Single Species System with Distributed Time Delay and Feedback Control

    Directory of Open Access Journals (Sweden)

    Yali Shen

    2012-01-01

    Full Text Available We study the permanence of a classofsingle species system with distributed time delay and feedback controls. General criteria on permanence are established in this paper. A very important fact is found in our results; that is, the feedback control is harmless to the permanence of species.

  7. Robust H∞ Stabilization of Uncertain Linear Time-Delay System with Delayed/Undelayed State Feedback Controllers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper focuses on the H∞ controller design for linear systems with time-varying delays and norm bounded parameter perturbetions in the system state and control/disturbance. On the existence of delayed/undelayed full state feedback controllers, we present a sufficient condition and give a design method in the form of Riccati equation. The controller can not only stabilize the time-delay system, but also make the H∞ norm of the closed-loop system be less than a given bound. This result practically generalizes the related results in current literature.

  8. Missing and delayed auditory responses in young and older children with autism spectrum disorders

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    J. Christopher eEdgar

    2014-06-01

    Full Text Available Background: The development of left and right superior temporal gyrus (STG 50ms (M50 and 100ms (M100 auditory responses in typically developing children (TD and in children with autism spectrum disorder (ASD was examined. It was hypothesized that (1 M50 responses would be observed equally often in younger and older children, (2 M100 responses would be observed more often in older than younger children indicating later development of secondary auditory areas, and (3 M100 but not M50 would be observed less often in ASD than TD in both age groups, reflecting slower maturation of later developing auditory areas in ASD. Methods: 35 typically developing controls, 63 ASD without language impairment (ASD-LI, and 38 ASD with language impairment (ASD+LI were recruited.The presence or absence of a STG M50 and M100 was scored. Subjects were grouped into younger (6 to 10-years-old and older groups (11 to 15-years-old. Results: Although M50 responses were observed equally often in older and younger subjects and equally often in TD and ASD, left and right M50 responses were delayed in ASD-LI and ASD+LI. Group comparisons showed that in younger subjects M100 responses were observed more often in TD than ASD+LI (90% vs 66%, p=0.04, with no differences between TD and ASD-LI (90% vs 76% p=0.14 or between ASD-LI and ASD+LI (76% vs 66%, p=0.53. In older subjects, whereas no differences were observed between TD and ASD+LI, responses were observed more often in ASD-LI than ASD+LI. Conclusions: Although present in all groups, M50 responses were delayed in ASD, suggesting delayed development of earlier developing auditory areas. Examining the TD data, findings indicated that by 11 years a right M100 should be observed in 100% of subjects and a left M100 in 80% of subjects. Thus, by 11years, lack of a left and especially right M100 offers neurobiological insight into sensory processing that may underlie language or cognitive impairment.

  9. Single photon delayed feedback: a way to stabilize intrinsic quantum cavity electrodynamics.

    Science.gov (United States)

    Carmele, Alexander; Kabuss, Julia; Schulze, Franz; Reitzenstein, Stephan; Knorr, Andreas

    2013-01-01

    We propose a scheme to control cavity quantum electrodynamics in the single photon limit by delayed feedback. In our approach a single emitter-cavity system, operating in the weak coupling limit, can be driven into the strong coupling-type regime by an external mirror: The external loop produces Rabi oscillations directly connected to the electron-photon coupling strength. As an expansion of typical cavity quantum electrodynamics, we treat the quantum correlation of external and internal light modes dynamically and demonstrate a possible way to implement a fully quantum mechanical time-delayed feedback. Our theoretical approach proposes a way to experimentally feedback control quantum correlations in the single photon limit.

  10. Adaptive NN backstepping output-feedback control for stochastic nonlinear strict-feedback systems with time-varying delays.

    Science.gov (United States)

    Chen, Weisheng; Jiao, Licheng; Li, Jing; Li, Ruihong

    2010-06-01

    For the first time, this paper addresses the problem of adaptive output-feedback control for a class of uncertain stochastic nonlinear strict-feedback systems with time-varying delays using neural networks (NNs). The circle criterion is applied to designing a nonlinear observer, and no linear growth condition is imposed on nonlinear functions depending on system states. Under the assumption that time-varying delays exist in the system output, only an NN is employed to compensate for all unknown nonlinear terms depending on the delayed output, and thus, the proposed control algorithm is more simple even than the existing NN backstepping control schemes for uncertain systems described by ordinary differential equations. Three examples are given to demonstrate the effectiveness of the control scheme proposed in this paper.

  11. Audiovisual Integration Delayed by Stimulus Onset Asynchrony Between Auditory and Visual Stimuli in Older Adults.

    Science.gov (United States)

    Ren, Yanna; Yang, Weiping; Nakahashi, Kohei; Takahashi, Satoshi; Wu, Jinglong

    2017-02-01

    Although neuronal studies have shown that audiovisual integration is regulated by temporal factors, there is still little knowledge about the impact of temporal factors on audiovisual integration in older adults. To clarify how stimulus onset asynchrony (SOA) between auditory and visual stimuli modulates age-related audiovisual integration, 20 younger adults (21-24 years) and 20 older adults (61-80 years) were instructed to perform an auditory or visual stimuli discrimination experiment. The results showed that in younger adults, audiovisual integration was altered from an enhancement (AV, A ± 50 V) to a depression (A ± 150 V). In older adults, the alterative pattern was similar to that for younger adults with the expansion of SOA; however, older adults showed significantly delayed onset for the time-window-of-integration and peak latency in all conditions, which further demonstrated that audiovisual integration was delayed more severely with the expansion of SOA, especially in the peak latency for V-preceded-A conditions in older adults. Our study suggested that audiovisual facilitative integration occurs only within a certain SOA range (e.g., -50 to 50 ms) in both younger and older adults. Moreover, our results confirm that the response for older adults was slowed and provided empirical evidence that integration ability is much more sensitive to the temporal alignment of audiovisual stimuli in older adults.

  12. Vowel generalization and its relation to adaptation during perturbations of auditory feedback.

    Science.gov (United States)

    Reilly, Kevin J; Pettibone, Chelsea

    2017-08-23

    Repeated perturbations of auditory feedback during vowel production elicit changes not only in the production of the perturbed vowel (adaptation) but also in the production of nearby vowels that were not perturbed (generalization). The finding that adaptation generalizes to other, non-perturbed vowels suggest that sensorimotor representations for vowels are not independent; instead the goals for producing any one vowel may depend in part on the goals for other vowels. The present study investigated the dependence or independence of vowel representations by evaluating adaptation and generalization in two groups of speakers exposed to auditory perturbations of their first formant (F1) during different vowels. The speakers in both groups who adapted to the perturbation exhibited generalization in two non-perturbed vowels that were produced under masking noise. Correlation testing was performed to evaluate the relations between adaptation and generalization as well as between the generalization in the two non-perturbed vowels. These tests identified significant coupling between the F1 changes of adjacent vowels but not non-adjacent vowels. The pattern of correlation findings indicates that generalization was due in part to feedforward representations that are partly shared across adjacent vowels, possibly to maintain their acoustic contrast. Copyright © 2016, Journal of Neurophysiology.

  13. Dynamic behavior of time-delayed acceleration feedback controller for active vibration control of flexible structures

    Science.gov (United States)

    An, Fang; Chen, Wei-dong; Shao, Min-qiang

    2014-09-01

    This paper addresses the design problem of the controller with time-delayed acceleration feedback. On the basis of the reduction method and output state-derivative feedback, a time-delayed acceleration feedback controller is proposed. Stability boundaries of the closed-loop system are determined by using Hurwitz stability criteria. Due to the introduction of time delay into the controller with acceleration feedback, the proposed controller has the feature of not only changing the mass property but also altering the damping property of the controlled system in the sense of equivalent structural modification. With this feature, the closed-loop system has a greater logarithmic decrement than the uncontrolled one, and in turn, the control behavior can be improved. In this connection, the time delay in the acceleration feedback control is a positive factor when satisfying some given conditions and it could be actively utilized. On the ground of the analysis, the developed controller is implemented on a cantilever beam for different controller gain-delay combinations, and the control performance is evaluated with the comparison to that of pure acceleration feedback controller. Simulation and experimental results verify the ability of the controller to attenuate the vibration resulting from the dominant mode.

  14. Information thermodynamics for a multi-feedback process with time delay

    Science.gov (United States)

    Kwon, Chulan; Um, Jaegon; Park, Hyunggyu

    2017-01-01

    We investigate a measurement-feedback process of repeated operations with time delay. During a finite-time interval, measurement on the system is performed and the feedback protocol derived from the measurement outcome is applied with time delay. This protocol is maintained into the next interval until a new protocol from the next measurement is applied. Unlike a feedback process without delay, both memories associated with previous and present measurement outcomes are involved in the system dynamics, which naturally brings forth a joint system described by a system state and two memory states. The thermodynamic second law provides a lower bound for heat flow into a thermal reservoir by the (3-state) Shannon entropy change of the joint system. However, as the feedback protocol depends on memory states sequentially, we can deduce a tighter bound for heat flow by integrating out irrelevant memory states during dynamics. As a simple example, we consider the so-called cold damping feedback process where the velocity of a particle is measured and a dissipative feedback protocol is applied to decelerate the particle. We confirm that the heat flow is well above the tightest bound. We also examine the long-time limit of this feedback process, which turns out to exhibit an interesting instability transition as well as heating by controlling parameters such as measurement errors, time interval, protocol strength, and time delay length. We discuss the underlying mechanism for instability and heating, which might be unavoidable in reality.

  15. Compensation for time-delayed feedback bang-bang control of quasi-integrable Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The stochastic averaging method for quasi-integrable Hamiltonian systems with time-delayed feedback bang-bang control is first introduced. Then, two time delay compensation methods, namely the method of changing control force amplitude (CFA) and the method of changing control delay time (CDT), are proposed. The conditions applicable to each compensation method are discussed. Finally, an example is worked out in detail to illustrate the application and effectiveness of the proposed methods and the two compensation methods in combination.

  16. Bubbling effect in the electro-optic delayed feedback oscillator coupled network

    Science.gov (United States)

    Liu, Lingfeng; Lin, Jun; Miao, Suoxia

    2017-03-01

    Synchronization in the optical systems coupled network always suffers from bubbling events. In this paper, we numerically investigate the statistical properties of the synchronization characteristics and bubbling effects in the electro-optic delayed feedback oscillator coupled network with different coupling strength, delay time and gain coefficient. Furthermore, we compare our results with the synchronization properties of semiconductor laser (SL) coupled network, which indicates that the electro-optic delayed feedback oscillator can be better to suppress the bubbling effects in the synchronization of coupled network under the same conditions.

  17. Time-Delayed Feedback Control in a Single-Mode Laser System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of time-delayed feedback control in a single-mode laser system is investigated. Using the small time delay approximation, the analytic expression of the stationary probability distribution function of the laser field is obtaincd. The mean, normalized variance and skewness of the steady-state laser intensity are calculated. It is found that the time-delayed feedback control can suppress the intensity fluctuation of the laser system. The numerical simulations are in good agreement with the approximate analytic results.

  18. Psycho-physiological assessment of a prosthetic hand sensory feedback system based on an auditory display: a preliminary study

    Directory of Open Access Journals (Sweden)

    Gonzalez Jose

    2012-06-01

    Full Text Available Abstract Background Prosthetic hand users have to rely extensively on visual feedback, which seems to lead to a high conscious burden for the users, in order to manipulate their prosthetic devices. Indirect methods (electro-cutaneous, vibrotactile, auditory cues have been used to convey information from the artificial limb to the amputee, but the usability and advantages of these feedback methods were explored mainly by looking at the performance results, not taking into account measurements of the user’s mental effort, attention, and emotions. The main objective of this study was to explore the feasibility of using psycho-physiological measurements to assess cognitive effort when manipulating a robot hand with and without the usage of a sensory substitution system based on auditory feedback, and how these psycho-physiological recordings relate to temporal and grasping performance in a static setting. Methods 10 male subjects (26+/-years old, participated in this study and were asked to come for 2 consecutive days. On the first day the experiment objective, tasks, and experiment setting was explained. Then, they completed a 30 minutes guided training. On the second day each subject was tested in 3 different modalities: Auditory Feedback only control (AF, Visual Feedback only control (VF, and Audiovisual Feedback control (AVF. For each modality they were asked to perform 10 trials. At the end of each test, the subject had to answer the NASA TLX questionnaire. Also, during the test the subject’s EEG, ECG, electro-dermal activity (EDA, and respiration rate were measured. Results The results show that a higher mental effort is needed when the subjects rely only on their vision, and that this effort seems to be reduced when auditory feedback is added to the human-machine interaction (multimodal feedback. Furthermore, better temporal performance and better grasping performance was obtained in the audiovisual modality. Conclusions The performance

  19. Learning monopolies with delayed feedback on price expectations

    Science.gov (United States)

    Matsumoto, Akio; Szidarovszky, Ferenc

    2015-11-01

    We call the intercept of the price function with the vertical axis the maximum price and the slope of the price function the marginal price. In this paper it is assumed that a monopolistic firm has full information about the marginal price and its own cost function but is uncertain on the maximum price. However, by repeated interaction with the market, the obtained price observations give a basis for an adaptive learning process of the maximum price. It is also assumed that the price observations have fixed delays, so the learning process can be described by a delayed differential equation. In the cases of one or two delays, the asymptotic behavior of the resulting dynamic process is examined, stability conditions are derived. Three main results are demonstrated in the two delay learning processes. First, it is possible to stabilize the equilibrium which is unstable in the one delay model. Second, complex dynamics involving chaos, which is impossible in the one delay model, can emerge. Third, alternations of stability and instability (i.e., stability switches) occur repeatedly.

  20. Active vibration control for nonlinear vehicle suspension with actuator delay via I/O feedback linearization

    Science.gov (United States)

    Lei, Jing; Jiang, Zuo; Li, Ya-Li; Li, Wu-Xin

    2014-10-01

    The problem of nonlinear vibration control for active vehicle suspension systems with actuator delay is considered. Through feedback linearization, the open-loop nonlinearity is eliminated by the feedback nonlinear term. Based on the finite spectrum assignment, the quarter-car suspension system with actuator delay is converted into an equivalent delay-free one. The nonlinear control includes a linear feedback term, a feedforward compensator, and a control memory term, which can be derived from a Riccati equation and a Sylvester equation, so that the effects produced by the road disturbances and the actuator delay are compensated, respectively. A predictor is designed to implement the predictive state in the designed control. Moreover, a reduced-order observer is constructed to solve its physical unrealisability problem. The stability proofs for the zero dynamics and the closed-loop system are provided. Numerical simulations illustrate the effectiveness and the simplicity of the designed control.

  1. Effects of time-delayed feedback on the properties of self-sustained oscillators

    Science.gov (United States)

    Risau-Gusman, S.

    2016-10-01

    Most self-sustained oscillations in biological systems and in technical applications are based on a feedback loop, and it is usually important to know how they will react when an external oscillatory force is applied. Here we investigate the effects that the introduction of a time delay in the feedback can have in the entrainment properties of self-sustained oscillators. To do this, we derive analytic expressions for the periodic trajectories and their asymptotic stability, for a generic external oscillatory force. This allows us to show that, for large quality factors, the resonance frequency does not depend on the feedback delay. When the external force is harmonic, it is shown that the largest entrainment range does not correspond to the time delay that gives the maximal response of the unforced oscillator. In fact, that delay gives the shortest entrainment range.

  2. H{sup {infinity}} State Feedback Control for Generalized Continuous/Discrete Time Delay System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.H.; Lee, S.K.; Park, H.B. [Kyungpook National University, Taegu (Korea, Republic of); Jeung, E.T. [Changwon National University, Changwon (Korea, Republic of)

    1998-04-01

    In this paper, we consider the problem of designing H{sup {infinity}} state feedback controller for the generalized time delay systems with delayed states and control inputs in continuous and discrete time cases, respectively. The generalized time delay system problems are solved on the basis of LMI(linear matrix inequality) technique considering time delays. The sufficient condition for the existence of controller and H{sup {infinity}} state feedback controller design methods are presented. Also, using some changes of variables and Schur complements, the obtained sufficient condition can be rewritten as a LMI form in terms of transformed variables. The proposed controller design method can be extended into the problem of robust H{sup {infinity}} state feedback controller design method easily. (author). 15 refs.

  3. A software module for implementing auditory and visual feedback on a video-based eye tracking system

    Science.gov (United States)

    Rosanlall, Bharat; Gertner, Izidor; Geri, George A.; Arrington, Karl F.

    2016-05-01

    We describe here the design and implementation of a software module that provides both auditory and visual feedback of the eye position measured by a commercially available eye tracking system. The present audio-visual feedback module (AVFM) serves as an extension to the Arrington Research ViewPoint EyeTracker, but it can be easily modified for use with other similar systems. Two modes of audio feedback and one mode of visual feedback are provided in reference to a circular area-of-interest (AOI). Auditory feedback can be either a click tone emitted when the user's gaze point enters or leaves the AOI, or a sinusoidal waveform with frequency inversely proportional to the distance from the gaze point to the center of the AOI. Visual feedback is in the form of a small circular light patch that is presented whenever the gaze-point is within the AOI. The AVFM processes data that are sent to a dynamic-link library by the EyeTracker. The AVFM's multithreaded implementation also allows real-time data collection (1 kHz sampling rate) and graphics processing that allow display of the current/past gaze-points as well as the AOI. The feedback provided by the AVFM described here has applications in military target acquisition and personnel training, as well as in visual experimentation, clinical research, marketing research, and sports training.

  4. Auditory Brainstem Response Wave Amplitude Characteristics as a Diagnostic Tool in Children with Speech Delay with Unknown Causes

    Directory of Open Access Journals (Sweden)

    Susan Abadi

    2016-09-01

    Full Text Available Speech delay with an unknown cause is a problem among children. This diagnosis is the last differential diagnosis after observing normal findings in routine hearing tests. The present study was undertaken to determine whether auditory brainstem responses to click stimuli are different between normally developing children and children suffering from delayed speech with unknown causes. In this cross-sectional study, we compared click auditory brainstem responses between 261 children who were clinically diagnosed with delayed speech with unknown causes based on normal routine auditory test findings and neurological examinations and had >12 months of speech delay (case group and 261 age- and sex-matched normally developing children (control group. Our results indicated that the case group exhibited significantly higher wave amplitude responses to click stimuli (waves I, III, and V than did the control group (P=0.001. These amplitudes were significantly reduced after 1 year (P=0.001; however, they were still significantly higher than those of the control group (P=0.001. The significant differences were seen regardless of the age and the sex of the participants. There were no statistically significant differences between the 2 groups considering the latency of waves I, III, and V. In conclusion, the higher amplitudes of waves I, III, and V, which were observed in the auditory brainstem responses to click stimuli among the patients with speech delay with unknown causes, might be used as a diagnostic tool to track patients’ improvement after treatment.

  5. Optimization of time-delayed feedback control of seismically excited building structures

    Institute of Scientific and Technical Information of China (English)

    Xue-ping LI; Wei-qiu ZHU; Zu-guang YING

    2008-01-01

    An optimization method for time-delayed feedback control of partially observable linear building structures subjected to seismic excitation is proposed. A time-delayed control problem of partially observable linear building structure under horizontal ground acceleration excitation is formulated and converted into that of completely observable linear structure by using separation principle. The time-delayed control forces are approximately expressed in terms of control forces without time delay. The control system is then governed by Ito stochastic differential equations for the conditional means of system states and then transformed into those for the conditional means of modal energies by using the stochastic averaging method for quasi-Hamiltonian systems. The control law is assumed to be modal velocity feedback control with time delay and the unknown control gains are determined by the modal performance indices. A three-storey building structure is taken as example to illustrate the proposal method and the numerical results are confirmed by using Monte Carlo simulation.

  6. Impact of time delays on oscillatory dynamics of interlinked positive and negative feedback loops

    Science.gov (United States)

    Huang, Bo; Tian, Xinyu; Liu, Feng; Wang, Wei

    2016-11-01

    Interlinking a positive feedback loop (PFL) with a negative feedback loop (NFL) constitutes a typical motif in genetic networks, performing various functions in cell signaling. How time delay in feedback regulation affects the dynamics of such systems still remains unclear. Here, we investigate three systems of interlinked PFL and NFL with time delays: a synthetic genetic oscillator, a three-node circuit, and a simplified single-node model. The stability of steady states and the routes to oscillation in the single-node model are analyzed in detail. The amplitude and period of oscillations vary with a pointwise periodicity over a range of time delay. Larger-amplitude oscillations can be induced when the PFL has an appropriately long delay, in comparison with the PFL with no delay or short delay; this conclusion holds true for all the three systems. We unravel the underlying mechanism for the above effects via analytical derivation under a limiting condition. We also develop a stochastic algorithm for simulating a single reaction with two delays and show that robust oscillations can be maintained by the PFL with a properly long delay in the single-node system. This work presents an effective method for constructing robust large-amplitude oscillators and interprets why similar circuit architectures are engaged in timekeeping systems such as circadian clocks.

  7. The role of time delay in adaptive cellular negative feedback systems.

    Science.gov (United States)

    Lapytsko, Anastasiya; Schaber, Jörg

    2016-06-07

    Adaptation in cellular systems is often mediated by negative feedbacks, which usually come with certain time delays causing several characteristic response patterns including an overdamped response, damped or sustained oscillations. Here, we analyse generic two-dimensional delay differential equations with delayed negative feedback describing the dynamics of biochemical adaptive signal-response networks. We derive explicit thresholds and boundaries showing how time delay determines characteristic response patterns of these networks. Applying our theoretical analyses to concrete data we show that adaptation to osmotic stress in yeast is optimal in the sense of minimizing adaptation time without causing oscillatory behaviour, i.e., a critically damped response. In addition, our framework demonstrates that a slight increase of time delay in the NF-κB system might induce a switch from damped to sustained oscillatory behaviour. Thus, we demonstrate how delay differential equations can be used to explicitly study the delay in biochemical negative feedback systems. Our analysis also provides insight into how time delay may tune biological signal-response patterns and control the systems behaviour.

  8. Stability of Nonlinear Systems with Unknown Time-varying Feedback Delay

    Science.gov (United States)

    Chunodkar, Apurva A.; Akella, Maruthi R.

    2013-12-01

    This paper considers the problem of stabilizing a class of nonlinear systems with unknown bounded delayed feedback wherein the time-varying delay is 1) piecewise constant 2) continuous with a bounded rate. We also consider application of these results to the stabilization of rigid-body attitude dynamics. In the first case, the time-delay in feedback is modeled specifically as a switch among an arbitrarily large set of unknown constant values with a known strict upper bound. The feedback is a linear function of the delayed states. In the case of linear systems with switched delay feedback, a new sufficiency condition for average dwell time result is presented using a complete type Lyapunov-Krasovskii (L-K) functional approach. Further, the corresponding switched system with nonlinear perturbations is proven to be exponentially stable inside a well characterized region of attraction for an appropriately chosen average dwell time. In the second case, the concept of the complete type L-K functional is extended to a class of nonlinear time-delay systems with unknown time-varying time-delay. This extension ensures stability robustness to time-delay in the control design for all values of time-delay less than the known upper bound. Model-transformation is used in order to partition the nonlinear system into a nominal linear part that is exponentially stable with a bounded perturbation. We obtain sufficient conditions which ensure exponential stability inside a region of attraction estimate. A constructive method to evaluate the sufficient conditions is presented together with comparison with the corresponding constant and piecewise constant delay. Numerical simulations are performed to illustrate the theoretical results of this paper.

  9. Task-specific modulation of human auditory evoked responses in a delayed-match-to-sample task

    Directory of Open Access Journals (Sweden)

    Feng eRong

    2011-05-01

    Full Text Available In this study, we focus our investigation on task-specific cognitive modulation of early cortical auditory processing in human cerebral cortex. During the experiments, we acquired whole-head magnetoencephalography (MEG data while participants were performing an auditory delayed-match-to-sample (DMS task and associated control tasks. Using a spatial filtering beamformer technique to simultaneously estimate multiple source activities inside the human brain, we observed a significant DMS-specific suppression of the auditory evoked response to the second stimulus in a sound pair, with the center of the effect being located in the vicinity of the left auditory cortex. For the right auditory cortex, a non-invariant suppression effect was observed in both DMS and control tasks. Furthermore, analysis of coherence revealed a beta band (12 ~ 20 Hz DMS-specific enhanced functional interaction between the sources in left auditory cortex and those in left inferior frontal gyrus, which has been shown to involve in short-term memory processing during the delay period of DMS task. Our findings support the view that early evoked cortical responses to incoming acoustic stimuli can be modulated by task-specific cognitive functions by means of frontal-temporal functional interactions.

  10. Stability and Performance of First-Order Linear Time-Delay Feedback Systems: An Eigenvalue Approach

    Directory of Open Access Journals (Sweden)

    Shu-An He

    2011-01-01

    Full Text Available Linear time-delay systems with transcendental characteristic equations have infinitely many eigenvalues which are generally hard to compute completely. However, the spectrum of first-order linear time-delay systems can be analyzed with the Lambert function. This paper studies the stability and state feedback stabilization of first-order linear time-delay system in detail via the Lambert function. The main issues concerned are the rightmost eigenvalue locations, stability robustness with respect to delay time, and the response performance of the closed-loop system. Examples and simulations are presented to illustrate the analysis results.

  11. Waiting for feedback helps if you want to know the answer: the role of curiosity in the delay-of-feedback benefit.

    Science.gov (United States)

    Mullaney, Kellie M; Carpenter, Shana K; Grotenhuis, Courtney; Burianek, Steven

    2014-11-01

    When participants answer a test question and then receive feedback of the correct answer, studies have shown that the feedback is more effective when it is delayed by several seconds rather than provided immediately (e.g., Brackbill & Kappy, Journal of Comparative and Physiological Psychology, 55, 14-18, 1962; Schroth, Contemporary Educational Psychology, 17, 78-82, 1992). Despite several demonstrations of this delay-of-feedback benefit, a theoretical explanation for this finding has not yet been developed. The present study tested the hypothesis that brief delays of feedback are beneficial because they encourage anticipation of the upcoming feedback. In Experiment 1, participants answered obscure trivia questions, and before receiving the answer, they rated their curiosity to know the answer. The answer was then provided either immediately or after a 4-s delay. A later final test over the same questions revealed a significant delay-of-feedback benefit, but only for items that had been rated high in curiosity. Experiment 2 replicated this same effect and showed that the delay-of-feedback benefit only occurs when feedback is provided after a variable, unpredictable time duration (either 2, 4, or 8 s) rather than after a constant duration (always 4 s). These findings demonstrate that the delay-of-feedback effect appears to be greatest under conditions in which participants are curious to know the answer and when the answer is provided after an unpredictable time interval.

  12. Winner-take-all selection in a neural system with delayed feedback

    CERN Document Server

    Brandt, Sebastian F

    2007-01-01

    We consider the effects of temporal delay in a neural feedback system with excitation and inhibition. The topology of our model system reflects the anatomy of the avian isthmic circuitry, a feedback structure found in all classes of vertebrates. We show that the system is capable of performing a `winner-take-all' selection rule for certain combinations of excitatory and inhibitory feedback. In particular, we show that when the time delays are sufficiently large a system with local inhibition and global excitation can function as a `winner-take-all' network and exhibit oscillatory dynamics. We demonstrate how the origin of the oscillations can be attributed to the finite delays through a linear stability analysis.

  13. Inducing or suppressing chaos in a double-well Duffing oscillator by time delay feedback

    Energy Technology Data Exchange (ETDEWEB)

    Sun Zhongkui [Department of Applied Mathematics, Northwestern Polytechnic University, Xi' an 710072 (China)] e-mail: sunzk205@mail.nwpu.edu.cn; Xu Wei [Department of Applied Mathematics, Northwestern Polytechnic University, Xi' an 710072 (China)] e-mail: weixu@nwpu.edu.cn; Yang Xiaoli [Department of Applied Mathematics, Northwestern Polytechnic University, Xi' an 710072 (China); Department of Mathematics, Shaan' xi Normal University, Xi' an 710062 (China); Fang Tong [Department of Applied Mechanics, Northwestern Polytechnic University, Xi' an 710072 (China)

    2006-02-01

    The chaotic behavior of a double-well Duffing oscillator with both delayed displacement and velocity feedbacks under a harmonic excitation is investigated. By means of the Melnikov technique, necessary condition for onset of chaos resulting from homoclinic bifurcation is derived analytically. The analytical results reveal that for negative feedback the presence of time delay lowers the threshold and enlarges the possible chaotic domain in parameter space; while for positive feedback the presence of time delay enhances the threshold and reduces the possible chaotic domain in parameter space, which are further verified numerically through Poincare maps of the original system. Furthermore, the effect of the control gain parameters on the chaotic motion of the original system is studied in detail.

  14. Multi-objective optimal design of active vibration absorber with delayed feedback

    Science.gov (United States)

    Huan, Rong-Hua; Chen, Long-Xiang; Sun, Jian-Qiao

    2015-03-01

    In this paper, a multi-objective optimal design of delayed feedback control of an actively tuned vibration absorber for a stochastically excited linear structure is investigated. The simple cell mapping (SCM) method is used to obtain solutions of the multi-objective optimization problem (MOP). The continuous time approximation (CTA) method is applied to analyze the delayed system. Stability is imposed as a constraint for MOP. Three conflicting objective functions including the peak frequency response, vibration energy of primary structure and control effort are considered. The Pareto set and Pareto front for the optimal feedback control design are presented for two examples. Numerical results have found that the Pareto optimal solutions provide effective delayed feedback control design.

  15. Functional role of delta and theta band oscillations for auditory feedback processing during vocal pitch motor control.

    Science.gov (United States)

    Behroozmand, Roozbeh; Ibrahim, Nadine; Korzyukov, Oleg; Robin, Donald A; Larson, Charles R

    2015-01-01

    The answer to the question of how the brain incorporates sensory feedback and links it with motor function to achieve goal-directed movement during vocalization remains unclear. We investigated the mechanisms of voice pitch motor control by examining the spectro-temporal dynamics of EEG signals when non-musicians (NM), relative pitch (RP), and absolute pitch (AP) musicians maintained vocalizations of a vowel sound and received randomized ± 100 cents pitch-shift stimuli in their auditory feedback. We identified a phase-synchronized (evoked) fronto-central activation within the theta band (5-8 Hz) that temporally overlapped with compensatory vocal responses to pitch-shifted auditory feedback and was significantly stronger in RP and AP musicians compared with non-musicians. A second component involved a non-phase-synchronized (induced) frontal activation within the delta band (1-4 Hz) that emerged at approximately 1 s after the stimulus onset. The delta activation was significantly stronger in the NM compared with RP and AP groups and correlated with the pitch rebound error (PRE), indicating the degree to which subjects failed to re-adjust their voice pitch to baseline after the stimulus offset. We propose that the evoked theta is a neurophysiological marker of enhanced pitch processing in musicians and reflects mechanisms by which humans incorporate auditory feedback to control their voice pitch. We also suggest that the delta activation reflects adaptive neural processes by which vocal production errors are monitored and used to update the state of sensory-motor networks for driving subsequent vocal behaviors. This notion is corroborated by our findings showing that larger PREs were associated with greater delta band activity in the NM compared with RP and AP groups. These findings provide new insights into the neural mechanisms of auditory feedback processing for vocal pitch motor control.

  16. Functional role of delta and theta band oscillations for auditory feedback processing during vocal pitch motor control

    Directory of Open Access Journals (Sweden)

    Roozbeh eBehroozmand

    2015-03-01

    Full Text Available The answer to the question of how the brain incorporates sensory feedback and links it with motor function to achieve goal-directed movement during vocalization remains unclear. We investigated the mechanisms of voice pitch motor control by examining the spectro-temporal dynamics of EEG signals when non-musicians (NM, relative pitch (RP and absolute pitch (AP musicians maintained vocalizations of a vowel sound and received randomized ±100 cents pitch-shift stimuli in their auditory feedback. We identified a phase-synchronized (evoked fronto-central activation within the theta band (5-8 Hz that temporally overlapped with compensatory vocal responses to pitch-shifted auditory feedback and was significantly stronger in RP and AP musicians compared with non-musicians. A second component involved a non-phase-synchronized (induced frontal activation within the delta band (1-4 Hz that emerged at approximately 1 second after the stimulus onset. The delta activation was significantly stronger in the NM compared with RP and AP groups and correlated with the pitch rebound error (PRE, indicating the degree to which subjects failed to re-adjust their voice pitch to baseline after the stimulus offset. We propose that the evoked theta is a neurophysiological marker of enhanced pitch processing in musicians and reflects mechanisms by which humans incorporate auditory feedback to control their voice pitch. We also suggest that the delta activation reflects adaptive neural processes by which vocal production errors are monitored and used to update the state of sensory-motor networks for driving subsequent vocal behaviors. This notion is corroborated by our findings showing that larger PREs were associated with greater delta band activity in the NM compared with RP and AP groups. These findings provide new insights into the neural mechanisms of auditory feedback processing for vocal pitch motor control.

  17. Delay-dependent H-infinity control for continuous time-delay systems via state feedback

    Institute of Scientific and Technical Information of China (English)

    Xinchun JIA; Yibo GAO; Jingmei ZHANG; Nanning ZHENG

    2007-01-01

    The delay-dependent H-infinity analysis and H-infinity control problems for continuous time-delay systems are studied. By introducing an equality with some free weighting matrices, an improved criterion of delay-dependent stability with H-infinity performance for such systems is presented, and a criterion of existence and some design methods of delay-dependent H-infinity controller for such systems are proposed in term of a set of matrix inequalities, which is solved efficiently by an iterative algorithm. Further, the corresponding results for the delay-dependent robust H-infinity analysis and robust H-infinity control problems for continuous time-delay uncertain systems are given. Finally, two numerical examples are given to illustrate the efficiency of the proposed method by comparing with the other existing results.

  18. Effects of Concurrent and Delayed Visual Feedback on Motor Memory Consolidation.

    Science.gov (United States)

    Wang, Dangxiao; Li, Teng; Yang, Gaofeng; Zhang, Yuru

    2017-02-22

    In many domains, it's important to understand the ways in which humans learn and develop new motor skills effectively and efficiently. For example, in dental operations, the ability to apply a weak force with a required tolerance is a fundamental skill to ensure diagnostic and treatment outcome, but acquiring such a skill is a challenge for novices. In this paper, we focus on motor memory for producing normally applied force by a hand-held probe and we compare the effects of two feedback methods on motor memory consolidation. Fourteen participants were randomly assigned to two groups: a Concurrent Group and a Delayed Group. Participants in the Concurrent Group were trained to apply a target force with concurrent visual feedback, while those in the Delayed Group were trained with delayed visual feedback. The task included two phases: a Training/Testing Phase, and a Retention Phase. The results indicated that participants in the Delayed Group obtained more effective learning outcomes and better retention effects. These findings provide a new perspective to explore the relationship between feedback methods and the cognitive process of motor skill learning, and open a new way to train motor skill using more effective methods than the traditional concurrent feedback approaches.

  19. Chaotification of Quasi-zero Stiffness System Via Direct Time-delay Feedback

    Directory of Open Access Journals (Sweden)

    Shuyong Liu

    2013-03-01

    Full Text Available This paper presents a chaotification method based on direct time-delay feedback control for a quasi-zero-stiffness isolation system. An analytical function of time-delay feedback control is derived based on differential-geometry control theory. Furthermore, the feasibility and effectiveness of this method was verified by numerical simulations. Numerical simulations show that this method holds the favorable aspects including the advantage of using tiny control gain, the capability of chaotifying across a large range of parametric domain and the high feasibility of the control implement.

  20. Adaptive output feedback control of a class of uncertain nonlinear systems with unknown time delays

    Science.gov (United States)

    Guan, Wei

    2012-04-01

    This article studies the adaptive output feedback control problem of a class of uncertain nonlinear systems with unknown time delays. The systems considered are dominated by a triangular system without zero dynamics satisfying linear growth in the unmeasurable states. The novelty of this article is that a universal-type adaptive output feedback controller is presented to time-delay systems, which can globally regulate all the states of the uncertain systems without knowing the growth rate. An illustrative example is provided to show the applicability of the developed control strategy.

  1. Global adaptive output feedback control for a class of nonlinear time-delay systems.

    Science.gov (United States)

    Zhai, Jun-yong; Zha, Wen-ting

    2014-01-01

    This paper addresses the problem of global output feedback control for a class of nonlinear time-delay systems. The nonlinearities are dominated by a triangular form satisfying linear growth condition in the unmeasurable states with an unknown growth rate. With a change of coordinates, a linear-like controller is constructed, which avoids the repeated derivatives of the nonlinearities depending on the observer states and the dynamic gain in backstepping approach and therefore, simplifies the design procedure. Using the idea of universal control, we explicitly construct a universal-type adaptive output feedback controller which globally regulates all the states of the nonlinear time-delay systems.

  2. Dynamic Output Feedback Control for Nonlinear Networked Control Systems with Random Packet Dropout and Random Delay

    Directory of Open Access Journals (Sweden)

    Shuiqing Yu

    2013-01-01

    Full Text Available This paper investigates the dynamic output feedback control for nonlinear networked control systems with both random packet dropout and random delay. Random packet dropout and random delay are modeled as two independent random variables. An observer-based dynamic output feedback controller is designed based upon the Lyapunov theory. The quantitative relationship of the dropout rate, transition probability matrix, and nonlinear level is derived by solving a set of linear matrix inequalities. Finally, an example is presented to illustrate the effectiveness of the proposed method.

  3. A frequency-selective feedback model of auditory efferent suppression and its implications for the recognition of speech in noise.

    Science.gov (United States)

    Clark, Nicholas R; Brown, Guy J; Jürgens, Tim; Meddis, Ray

    2012-09-01

    The potential contribution of the peripheral auditory efferent system to our understanding of speech in a background of competing noise was studied using a computer model of the auditory periphery and assessed using an automatic speech recognition system. A previous study had shown that a fixed efferent attenuation applied to all channels of a multi-channel model could improve the recognition of connected digit triplets in noise [G. J. Brown, R. T. Ferry, and R. Meddis, J. Acoust. Soc. Am. 127, 943-954 (2010)]. In the current study an anatomically justified feedback loop was used to automatically regulate separate attenuation values for each auditory channel. This arrangement resulted in a further enhancement of speech recognition over fixed-attenuation conditions. Comparisons between multi-talker babble and pink noise interference conditions suggest that the benefit originates from the model's ability to modify the amount of suppression in each channel separately according to the spectral shape of the interfering sounds.

  4. Adaptive output feedback control for nonlinear time-delay systems using neural network

    Institute of Scientific and Technical Information of China (English)

    Weisheng CHEN; Junmin LI

    2006-01-01

    This paper extends the adaptive neural network (NN) control approaches to a class of unknown output feedback nonlinear time-delay systems. An adaptive output feedback NN tracking controller is designed by backstepping technique. NNs are used to approximate unknown functions dependent on time delay. Delay-dependent filters are introduced for state estimation. The domination method is used to deal with the smooth time-delay basis functions. The adaptive bounding technique is employed to estimate the upper bound of the NN approximation errors. Based on LyapunovKrasovskii functional, the semi-global uniform ultimate boundedness of all the signals in the closed-loop system is proved.The feasibility is investigated by two illustrative simulation examples.

  5. State Feedback Consensus for Multi-Agent System with Multiple Time-Delays

    Directory of Open Access Journals (Sweden)

    Jia Wei

    2013-09-01

    Full Text Available In this paper, we study the multi-agent system to achieve a faster consensus with multiple time-delays under a directed asymmetric information exchange topology. We first assume that an agent processes its own state information with self-delay and receives state information from its neighbors with communication delays. Based on state proportion derivative feedback, the improved consensus protocol can accelerate the system to achieve a consensus. A sufficient condition for reaching consensus is then derived based on the Nyquist stability criterion and frequency domain analysis. In addition, a specific form of consensus equilibrium is obtained which is influenced by the initial states of agents, time-delays and state feedback intensity. Finally, simulations are presented to verify the validity of the theoretical results.

  6. Adaptive lag synchronization of uncertain dynamical systems with time delays via simple transmission lag feedback

    Institute of Scientific and Technical Information of China (English)

    Gu Wei-Dong; Sun Zhi-Yong; Wu Xiao-Ming; Yu Chang-Bin

    2013-01-01

    In this paper we present an adaptive scheme to achieve lag synchronization for uncertain dynamical systems with time delays and unknown parameters.In contrast to the nonlinear feedback scheme reported in the previous literature,the proposed controller is a linear one which only involves simple feedback information from the drive system with signal propagation lags.Besides,the unknown parameters can also be identified via the proposed updating laws in spite of the existence of model delays and transmission lags,as long as the linear independence condition between the related function elements is satisfied.Two examples,i.e.,the Mackey-Glass model with single delay and the Lorenz system with multiple delays,are employed to show the effectiveness of this approach.Some robustness issues are also discussed,which shows that the proposed scheme is quite robust in switching and noisy environment.

  7. HOPF BIFURCATION OF AN OSCILLATOR WITH QUADRATIC AND CUBIC NONLINEARITIES AND WITH DELAYED VELOCITY FEEDBACK

    Institute of Scientific and Technical Information of China (English)

    WANG Huailei; WANG Zaihua; HU Haiyan

    2004-01-01

    This paper studies the local dynamics of an SDOF system with quadratic and cubic stiffness terms, and with linear delayed velocity feedback. The analysis indicates that for a sufficiently large velocity feedback gain, the equilibrium of the system may undergo a number of stability switches with an increase of time delay, and then becomes unstable forever. At each critical value of time delay for which the system changes its stability, a generic Hopf bifurcation occurs and a periodic motion emerges in a one-sided neighbourhood of the critical time delay. The method of Fredholm alternative is applied to determine the bifurcating periodic motions and their stability. It stresses on the effect of the system parameters on the stable regions and the amplitudes of the bifurcating periodic solutions.

  8. Decentralized Output-Feedback Stabilization of Linear Time-invariant Interconnected Systems with Delays

    Energy Technology Data Exchange (ETDEWEB)

    Shim, D.S. [Chung-Ang University, Seoul (Korea, Republic of)

    1998-04-01

    We study the decentralized stabilization problem of linear time-invariant large-scale interconnected systems with delays without any system structure. We obtain sufficient stability conditions for interconnected systems which are equivalent to disturbance attenuation of some scaled system. A decentralized output-feedback controller is obtained using standard H{infinity} control theory. The obtained controller is delay-independent. We also obtain an observer for the interconnected system. (author). 9 refs.

  9. A matrix transformation approach to H∞ control via static output feedback for input delay systems

    OpenAIRE

    Du, B; Shu, Z; Lam, J.

    2009-01-01

    This paper addresses the static output feedback (SOF) H∞ control for continuous-time linear systems with an unknown input delay from a novel perspective. New equivalent characterizations on the stability and H∞ performance of the closed-loop system are established in terms of nonlinear matrix inequalities with free parametrization matrices. These delay-dependent characterizations possess a special monotonic structure, which leads to linearized iterative computation. The effectiveness and meri...

  10. Observer design and output feedback stabilization for linear singular time-delay systems with unknown inputs

    Institute of Scientific and Technical Information of China (English)

    Peng CUI; Chenghui ZHANG

    2008-01-01

    The design of a functional observer and reduced-order observer with internal delay for linear singular timedelay systems with unknown inputs is discussed.The sufficient conditions of the existence of observers,which are normal linear time-delay systems,and the corresponding design steps are presented via linear matrix inequality(LMI).Moreover,the observer-based feedback stabilizing controller is obtained.Three examples are given to show the effectiveness of the proposed methods.

  11. Incomplete state feedback for time delay systems: observer applications in multidelay compensation

    Energy Technology Data Exchange (ETDEWEB)

    Ogunnaike, B.A.; Ray, W.H.

    1984-09-01

    This paper demonstrates how a recently developed observer for time delay systems may be used to estimate needed state variables for implementation of multivariable time delay compensation. The general results are illustrated by an example of a multireactor plant in which only one reactor concentration can be measured. The observer worked well in simulation for both multivariable PID control and multidelay compensated PID control and allowed both schemes to function with estimated state variables in the feedback loop. 16 references, 5 figures.

  12. Recovery of systems with a linear filter and nonlinear delay feedback in periodic regimes.

    Science.gov (United States)

    Ponomarenko, V I; Prokhorov, M D

    2008-12-01

    We propose a set of methods for the estimation of the parameters of time-delay systems with a linear filter and nonlinear delay feedback performing periodic oscillations. The methods are based on an analysis of the system response to regular external perturbations and are valid only for systems whose dynamics can be perturbed. The efficiency of the methods is illustrated using both numerical and experimental data.

  13. Sensory Processing: Advances in Understanding Structure and Function of Pitch-Shifted Auditory Feedback in Voice Control

    Directory of Open Access Journals (Sweden)

    Charles R Larson

    2016-02-01

    Full Text Available The pitch-shift paradigm has become a widely used method for studying the role of voice pitch auditory feedback in voice control. This paradigm introduces small, brief pitch shifts in voice auditory feedback to vocalizing subjects. The perturbations trigger a reflexive mechanism that counteracts the change in pitch. The underlying mechanisms of the vocal responses are thought to reflect a negative feedback control system that is similar to constructs developed to explain other forms of motor control. Another use of this technique requires subjects to voluntarily change the pitch of their voice when they hear a pitch shift stimulus. Under these conditions, short latency responses are produced that change voice pitch to match that of the stimulus. The pitch-shift technique has been used with magnetoencephalography (MEG and electroencephalography (EEG recordings, and has shown that at vocal onset there is normally a suppression of neural activity related to vocalization. However, if a pitch-shift is also presented at voice onset, there is a cancellation of this suppression, which has been interpreted to mean that one way in which a person distinguishes self-vocalization from vocalization of others is by a comparison of the intended voice and the actual voice. Studies of the pitch shift reflex in the fMRI environment show that the superior temporal gyrus (STG plays an important role in the process of controlling voice F0 based on auditory feedback. Additional studies using fMRI for effective connectivity modeling show that the left and right STG play critical roles in correcting for an error in voice production. While both the left and right STG are involved in this process, a feedback loop develops between left and right STG during perturbations, in which the left to right connection becomes stronger, and a new negative right to left connection emerges along with the emergence of other feedback loops within the cortical network tested.

  14. Stabilizing fixed points of time-delay systems close to the Hopf bifurcation using a dynamic delayed feedback control method

    Energy Technology Data Exchange (ETDEWEB)

    Rezaie, B; Motlagh, M R Jahed; Analoui, M [Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Khorsandi, S [Amirkabir University of Technology, Hafez St., Tehran (Iran, Islamic Republic of)], E-mail: brezaie@iust.ac.ir

    2009-10-02

    This paper deals with the problem of Hopf bifurcation control for a class of nonlinear time-delay systems. A dynamic delayed feedback control method is utilized for stabilizing unstable fixed points near Hopf bifurcation. Using a linear stability analysis, we show that under certain conditions of the control parameters, and without changing the operating point of the system, the onset of Hopf bifurcation is delayed. Meanwhile, by applying the center manifold theorem and the normal form theory, we obtain formulas for determining the direction of the Hopf bifurcation and the stability of bifurcating periodic solutions of the closed loop system. Numerical simulations are given to justify the validity of the analytical results for the system controlled by the proposed method.

  15. Tcf4 transgenic female mice display delayed adaptation in an auditory latent inhibition paradigm.

    Science.gov (United States)

    Brzózka, M M; Rossner, M J; de Hoz, L

    2016-09-01

    Schizophrenia (SZ) is a severe mental disorder affecting about 1 % of the human population. Patients show severe deficits in cognitive processing often characterized by an improper filtering of environmental stimuli. Independent genome-wide association studies confirmed a number of risk variants for SZ including several associated with the gene encoding the transcription factor 4 (TCF4). TCF4 is widely expressed in the central nervous system of mice and humans and seems to be important for brain development. Transgenic mice overexpressing murine Tcf4 (Tcf4tg) in the adult brain display cognitive impairments and sensorimotor gating disturbances. To address the question of whether increased Tcf4 gene dosage may affect cognitive flexibility in an auditory associative task, we tested latent inhibition (LI) in female Tcf4tg mice. LI is a widely accepted translational endophenotype of SZ and results from a maladaptive delay in switching a response to a previously unconditioned stimulus when this becomes conditioned. Using an Audiobox, we pre-exposed Tcf4tg mice and their wild-type littermates to either a 3- or a 12-kHz tone before conditioning them to a 12-kHz tone. Tcf4tg animals pre-exposed to a 12-kHz tone showed significantly delayed conditioning when the previously unconditioned tone became associated with an air puff. These results support findings that associate TCF4 dysfunction with cognitive inflexibility and improper filtering of sensory stimuli observed in SZ patients.

  16. The Effects of Pitch Shifts on Delay-Induced Changes in Vocal Sequencing in a Songbird

    Science.gov (United States)

    Kelly, Conor W.

    2017-01-01

    Abstract Like human speech, vocal behavior in songbirds depends critically on auditory feedback. In both humans and songbirds, vocal skills are acquired by a process of imitation whereby current vocal production is compared to an acoustic target. Similarly, performance in adulthood relies strongly on auditory feedback, and online manipulations of auditory signals can dramatically alter acoustic production even after vocalizations have been well learned. Artificially delaying auditory feedback can disrupt both speech and birdsong, and internal delays in auditory feedback have been hypothesized as a cause of vocal dysfluency in persons who stutter. Furthermore, in both song and speech, online shifts of the pitch (fundamental frequency) of auditory feedback lead to compensatory changes in vocal pitch for small perturbations, but larger pitch shifts produce smaller changes in vocal output. Intriguingly, large pitch shifts can partially restore normal speech in some dysfluent speakers, suggesting that the effects of auditory feedback delays might be ameliorated by online pitch manipulations. Although birdsong provides a promising model system for understanding speech production, the interactions between sensory feedback delays and pitch shifts have not yet been assessed in songbirds. To investigate this, we asked whether the addition of a pitch shift modulates delay-induced changes in Bengalese finch song, hypothesizing that pitch shifts would reduce the effects of feedback delays. Compared with the effects of delays alone, combined delays and pitch shifts resulted in a significant reduction in behavioral changes in one type of sequencing (branch points) but not another (distribution of repeated syllables). PMID:28144622

  17. The Effects of Pitch Shifts on Delay-Induced Changes in Vocal Sequencing in a Songbird.

    Science.gov (United States)

    Wyatt, MacKenzie; Berthiaume, Emily A; Kelly, Conor W; Sober, Samuel J

    2017-01-01

    Like human speech, vocal behavior in songbirds depends critically on auditory feedback. In both humans and songbirds, vocal skills are acquired by a process of imitation whereby current vocal production is compared to an acoustic target. Similarly, performance in adulthood relies strongly on auditory feedback, and online manipulations of auditory signals can dramatically alter acoustic production even after vocalizations have been well learned. Artificially delaying auditory feedback can disrupt both speech and birdsong, and internal delays in auditory feedback have been hypothesized as a cause of vocal dysfluency in persons who stutter. Furthermore, in both song and speech, online shifts of the pitch (fundamental frequency) of auditory feedback lead to compensatory changes in vocal pitch for small perturbations, but larger pitch shifts produce smaller changes in vocal output. Intriguingly, large pitch shifts can partially restore normal speech in some dysfluent speakers, suggesting that the effects of auditory feedback delays might be ameliorated by online pitch manipulations. Although birdsong provides a promising model system for understanding speech production, the interactions between sensory feedback delays and pitch shifts have not yet been assessed in songbirds. To investigate this, we asked whether the addition of a pitch shift modulates delay-induced changes in Bengalese finch song, hypothesizing that pitch shifts would reduce the effects of feedback delays. Compared with the effects of delays alone, combined delays and pitch shifts resulted in a significant reduction in behavioral changes in one type of sequencing (branch points) but not another (distribution of repeated syllables).

  18. Fast negative feedback enables mammalian auditory nerve fibers to encode a wide dynamic range of sound intensities.

    Directory of Open Access Journals (Sweden)

    Mark Ospeck

    Full Text Available Mammalian auditory nerve fibers (ANF are remarkable for being able to encode a 40 dB, or hundred fold, range of sound pressure levels into their firing rate. Most of the fibers are very sensitive and raise their quiescent spike rate by a small amount for a faint sound at auditory threshold. Then as the sound intensity is increased, they slowly increase their spike rate, with some fibers going up as high as ∼300 Hz. In this way mammals are able to combine sensitivity and wide dynamic range. They are also able to discern sounds embedded within background noise. ANF receive efferent feedback, which suggests that the fibers are readjusted according to the background noise in order to maximize the information content of their auditory spike trains. Inner hair cells activate currents in the unmyelinated distal dendrites of ANF where sound intensity is rate-coded into action potentials. We model this spike generator compartment as an attenuator that employs fast negative feedback. Input current induces rapid and proportional leak currents. This way ANF are able to have a linear frequency to input current (f-I curve that has a wide dynamic range. The ANF spike generator remains very sensitive to threshold currents, but efferent feedback is able to lower its gain in response to noise.

  19. Directed Current Induced by an Symmetrically ac Force Coexisting with a Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    易述婷; 宋晖; 欧志娥; 艾保全; 熊建文

    2012-01-01

    We study the transport of overdamped Brownian particles in a symmetricaJly periodic potential in the presence of an asymmetrically ac driving force and a time-delayed feedback. It is found that for low frequencies, the average velocity can be negative by changing the driving amplitude, for high frequencies, there exists an optimized driving amplitude at which the average velocity takes its maximum value. Additionally, there is a threshold value of driving amplitude below which no directed transport can be obtained for high frequencies. For the large value of the delay time, the average velocity is independent of the delay time.

  20. Globally Asymptotic Stability of Stochastic Nonlinear Systems with Time-Varying Delays via Output Feedback Control

    Directory of Open Access Journals (Sweden)

    Mingzhu Song

    2016-01-01

    Full Text Available We address the problem of globally asymptotic stability for a class of stochastic nonlinear systems with time-varying delays. By the backstepping method and Lyapunov theory, we design a linear output feedback controller recursively based on the observable linearization for a class of stochastic nonlinear systems with time-varying delays to guarantee that the closed-loop system is globally asymptotically stable in probability. In particular, we extend the deterministic nonlinear system to stochastic nonlinear systems with time-varying delays. Finally, an example and its simulations are given to illustrate the theoretical results.

  1. The Impact of Immediate and Delayed Corrective Feedback on Iranian EFL Learners’ Willingness to Communicate

    Directory of Open Access Journals (Sweden)

    Mahtab Zadkhast

    2017-09-01

    Full Text Available The present study investigated the impact of immediate and delayed corrective feedback on Iranian EFL learners’ willingness to communicate. To attain the purpose of the study, 45 females intermediate students that were roughly selected according to their previous grades and their assigned  level in language school were chosen to participate in this study. Then they were divided to three equal groups: Experimental group 1(immediate feedback, Experimental group 2 (delayed feedback and control group. In the first session, WTC questionnaire (MacIntyre ,2001 modified by Pourya Baghaei and Ali Dourakhshan was administered to all groups as pretests. In group 1 the students’ errors were corrected by the teacher immediately after committing but in the second group, the students’ errors were written by the teacher and her comments were given to them when they finished their tasks. For the control group, the routine procedure of New Headway intermediate was followed. After about 12 sessions WTC was repeated as posttests. The findings revealed that immediate and delayed corrective feedback have a significant effect on EFL students’ level of WTC. The results, also demonstrated that experimental group 1 (immediate feedback outweighed the other two groups in relation to their WTC. The findings have implication for pedagogy as well as further research.

  2. The response of nonlinear controlled system under an external excitation via time delay state feedback

    Directory of Open Access Journals (Sweden)

    A.M. Elnaggar

    2016-01-01

    Full Text Available An analysis of primary, superharmonic of order five, and subharmonic of order one-three resonances for non-linear s.d.o.f. system with two distinct time-delays under an external excitation is investigated. The method of multiple scales is used to determine two first order ordinary differential equations which describe the modulation of the amplitudes and the phases. Steady-state solutions and their stabilities in each resonance are studied. Numerical results are obtained by using the Software of Mathematica, which presented in a group of figures. The effect of the feedback gains and time-delays on the non-linear response of the system is discussed and it is found that: an appropriate feedback can enhance the control performance. A suitable choice of the feedback gains and time-delays can enlarge the critical force amplitude, and reduce the peak amplitude of the response (or peak amplitude of the free oscillation term for the case of primary resonance (superharmonic resonance. Furthermore, a proper feedback can eliminate saddle-node bifurcation, thereby eliminating jump and hysteresis phenomena taking place in the corresponding uncontrolled system. For subharmonic resonance, an adequate feedback can reduce the regions of subharmonic resonance response.

  3. Non-Markovian spiking statistics of a neuron with delayed feedback in presence of refractoriness.

    Science.gov (United States)

    Kravchuk, Kseniia; Vidybida, Alexander

    2014-02-01

    Spiking statistics of a self-inhibitory neuron is considered. The neuron receives excitatory input from a Poisson stream and inhibitory impulses through a feedback line with a delay. After triggering, the neuron is in the refractory state for a positive period of time. Recently, [35,6], it was proven for a neuron with delayed feedback and without the refractory state, that the output stream of interspike intervals (ISI) cannot be represented as a Markov process. The refractory state presence, in a sense limits the memory range in the spiking process, which might restore Markov property to the ISI stream. Here we check such a possibility. For this purpose, we calculate the conditional probability density P (tn+1 l tn,...,t1,t0), and prove exactly that it does not reduce to P (tn+1 l tn,...,t1) for any n ⋝0. That means, that activity of the system with refractory state as well cannot be represented as a Markov process of any order. We conclude that it is namely the delayed feedback presence which results in non-Markovian statistics of neuronal firing. As delayed feedback lines are common for any realistic neural network, the non-Markovian statistics of the network activity should be taken into account in processing of experimental data.

  4. PERMANENCE AND GLOBAL STABILITY OF A FEEDBACK CONTROL SYSTEM WITH DELAYS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper considers a feedback control systems of differential equations with delays. By applying the differential inequality theorem, sufficient conditions for the permanence of the system are obtained. Also, by constructing a suitable Lyapunov functional, a criterion for the global stability of the model is obtained.

  5. Positive Periodic Solutions of Cooperative Systems with Delays and Feedback Controls

    Directory of Open Access Journals (Sweden)

    Tursuneli Niyaz

    2013-01-01

    Full Text Available This paper studies a class of periodic n species cooperative Lotka-Volterra systems with continuous time delays and feedback controls. Based on the continuation theorem of the coincidence degree theory developed by Gaines and Mawhin, some new sufficient conditions on the existence of positive periodic solutions are established.

  6. Delay Reduction for Instantly Decodable Network Coding in Persistent Channels With Feedback Imperfections

    KAUST Repository

    Douik, Ahmed S.

    2015-11-05

    This paper considers the multicast decoding delay reduction problem for generalized instantly decodable network coding (G-IDNC) over persistent erasure channels with feedback imperfections. The feedback scenario discussed is the most general situation in which the sender does not always receive acknowledgments from the receivers after each transmission and the feedback communications are subject to loss. The decoding delay increment expressions are derived and employed to express the decoding delay reduction problem as a maximum weight clique problem in the G-IDNC graph. This paper provides a theoretical analysis of the expected decoding delay increase at each time instant. Problem formulations in simpler channel and feedback models are shown to be special cases of the proposed generalized formulation. Since finding the optimal solution to the problem is known to be NP-hard, a suboptimal greedy algorithm is designed and compared with blind approaches proposed in the literature. Through extensive simulations, the proposed algorithm is shown to outperform the blind methods in all situations and to achieve significant improvement, particularly for high time-correlated channels.

  7. Delay-induced transport in a rocking ratchet under feedback control.

    Science.gov (United States)

    Loos, Sarah A M; Gernert, Robert; Klapp, Sabine H L

    2014-05-01

    Based on the Fokker-Planck equation we investigate the transport of an overdamped colloidal particle in a static, asymmetric periodic potential supplemented by a time-dependent, delayed feedback force, F(fc). For a given time t, F(fc) depends on the status of the system at a previous time t-τ(D), with τ(D) being a delay time, specifically on the delayed mean particle displacement (relative to some "switching position"). For nonzero delay times F(fc)(t) develops nearly regular oscillations, generating a net current in the system. Depending on the switching position, this current is nearly as large or even larger than that in a conventional open-loop rocking ratchet. We also investigate thermodynamic properties of the delayed nonequilibrium system and we suggest an underlying Langevin equation which reproduces the Fokker-Planck results.

  8. Analytical determination of the bifurcation thresholds in stochastic differential equations with delayed feedback.

    Science.gov (United States)

    Gaudreault, Mathieu; Drolet, François; Viñals, Jorge

    2010-11-01

    Analytical expressions for pitchfork and Hopf bifurcation thresholds are given for a nonlinear stochastic differential delay equation with feedback. Our results assume that the delay time τ is small compared to other characteristic time scales, not a significant limitation close to the bifurcation line. A pitchfork bifurcation line is found, the location of which depends on the conditional average , where x(t) is the dynamical variable. This conditional probability incorporates the combined effect of fluctuation correlations and delayed feedback. We also find a Hopf bifurcation line which is obtained by a multiple scale expansion around the oscillatory solution near threshold. We solve the Fokker-Planck equation associated with the slowly varying amplitudes and use it to determine the threshold location. In both cases, the predicted bifurcation lines are in excellent agreement with a direct numerical integration of the governing equations. Contrary to the known case involving no delayed feedback, we show that the stochastic bifurcation lines are shifted relative to the deterministic limit and hence that the interaction between fluctuation correlations and delay affect the stability of the solutions of the model equation studied.

  9. Stability and Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback

    Science.gov (United States)

    Liu, Shuang; Zhao, Shuang-Shuang; Wang, Zhao-Long; Li, Hai-Bin

    2015-01-01

    The stability and the Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback are studied. By considering the energy in the air-gap field of the AC motor, the dynamical equation of the electromechanical coupling transmission system is deduced and a time delay feedback is introduced to control the dynamic behaviors of the system. The characteristic roots and the stable regions of time delay are determined by the direct method, and the relationship between the feedback gain and the length summation of stable regions is analyzed. Choosing the time delay as a bifurcation parameter, we find that the Hopf bifurcation occurs when the time delay passes through a critical value. A formula for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions is given by using the normal form method and the center manifold theorem. Numerical simulations are also performed, which confirm the analytical results. Project supported by the National Natural Science Foundation of China (Grant No. 61104040), the Natural Science Foundation of Hebei Province, China (Grant No. E2012203090), and the University Innovation Team of Hebei Province Leading Talent Cultivation Project, China (Grant No. LJRC013).

  10. Overt vs. covert speed cameras in combination with delayed vs. immediate feedback to the offender.

    Science.gov (United States)

    Marciano, Hadas; Setter, Pe'erly; Norman, Joel

    2015-06-01

    Speeding is a major problem in road safety because it increases both the probability of accidents and the severity of injuries if an accident occurs. Speed cameras are one of the most common speed enforcement tools. Most of the speed cameras around the world are overt, but there is evidence that this can cause a "kangaroo effect" in driving patterns. One suggested alternative to prevent this kangaroo effect is the use of covert cameras. Another issue relevant to the effect of enforcement countermeasures on speeding is the timing of the fine. There is general agreement on the importance of the immediacy of the punishment, however, in the context of speed limit enforcement, implementing such immediate punishment is difficult. An immediate feedback that mediates the delay between the speed violation and getting a ticket is one possible solution. This study examines combinations of concealment and the timing of the fine in operating speed cameras in order to evaluate the most effective one in terms of enforcing speed limits. Using a driving simulator, the driving performance of the following four experimental groups was tested: (1) overt cameras with delayed feedback, (2) overt cameras with immediate feedback, (3) covert cameras with delayed feedback, and (4) covert cameras with immediate feedback. Each of the 58 participants drove in the same scenario on three different days. The results showed that both median speed and speed variance were higher with overt than with covert cameras. Moreover, implementing a covert camera system along with immediate feedback was more conducive to drivers maintaining steady speeds at the permitted levels from the very beginning. Finally, both 'overt cameras' groups exhibit a kangaroo effect throughout the entire experiment. It can be concluded that an implementation strategy consisting of covert speed cameras combined with immediate feedback to the offender is potentially an optimal way to motivate drivers to maintain speeds at the

  11. Neuronal mechanisms of voice control are affected by implicit expectancy of externally triggered perturbations in auditory feedback.

    Directory of Open Access Journals (Sweden)

    Oleg Korzyukov

    Full Text Available Accurate vocal production relies on several factors including sensory feedback and the ability to predict future challenges to the control processes. Repetitive patterns of perturbations in sensory feedback by themselves elicit implicit expectations in the vocal control system regarding the timing, quality and direction of perturbations. In the present study, the predictability of voice pitch-shifted auditory feedback was experimentally manipulated. A block of trials where all pitch-shift stimuli were upward, and therefore predictable was contrasted against an unpredictable block of trials in which the stimulus direction was randomized between upward and downward pitch-shifts. It was found that predictable perturbations in voice auditory feedback led to a reduction in the proportion of compensatory vocal responses, which might be indicative of a reduction in vocal control. The predictable perturbations also led to a reduction in the magnitude of the N1 component of cortical Event Related Potentials (ERP that was associated with the reflexive compensations to the perturbations. We hypothesize that formation of expectancy in our study is accompanied by involuntary allocation of attentional resources occurring as a result of habituation or learning, that in turn trigger limited and controlled exploration-related motor variability in the vocal control system.

  12. Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke

    Directory of Open Access Journals (Sweden)

    Reinkensmeyer David J

    2011-04-01

    Full Text Available Abstract Background Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task. Methods Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error. Results Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke. Conclusions Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for

  13. Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke

    Science.gov (United States)

    2011-01-01

    Background Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task. Methods Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error. Results Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke. Conclusions Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for the hemiparetic arm

  14. Modeling and Output Feedback Control of Networked Control Systems with Both Time Delays; and Packet Dropouts

    Directory of Open Access Journals (Sweden)

    Li Qiu

    2013-01-01

    Full Text Available This paper is concerned with the problem of modeling and output feedback controller design for a class of discrete-time networked control systems (NCSs with time delays and packet dropouts. A Markovian jumping method is proposed to deal with random time delays and packet dropouts. Different from the previous studies on the issue, the characteristics of networked communication delays and packet dropouts can be truly reflected by the unified model; namely, both sensor-to-controller (S-C and controller-to-actuator (C-A time delays, and packet dropouts are modeled and their history behavior is described by multiple Markov chains. The resulting closed-loop system is described by a new Markovian jump linear system (MJLS with Markov delays model. Based on Lyapunov stability theory and linear matrix inequality (LMI method, sufficient conditions of the stochastic stability and output feedback controller design method for NCSs with random time delays and packet dropouts are presented. A numerical example is given to illustrate the effectiveness of the proposed method.

  15. Delay reduction in lossy intermittent feedback for generalized instantly decodable network coding

    KAUST Repository

    Douik, Ahmed S.

    2013-10-01

    In this paper, we study the effect of lossy intermittent feedback loss events on the multicast decoding delay performance of generalized instantly decodable network coding. These feedback loss events create uncertainty at the sender about the reception statues of different receivers and thus uncertainty to accurately determine subsequent instantly decodable coded packets. To solve this problem, we first identify the different possibilities of uncertain packets at the sender and their probabilities. We then derive the expression of the mean decoding delay. We formulate the Generalized Instantly Decodable Network Coding (G-IDNC) minimum decoding delay problem as a maximum weight clique problem. Since finding the optimal solution is NP-hard, we design a variant of the algorithm employed in [1]. Our algorithm is compared to the two blind graph update proposed in [2] through extensive simulations. Results show that our algorithm outperforms the blind approaches in all the situations and achieves a tolerable degradation, against the perfect feedback, for large feedback loss period. © 2013 IEEE.

  16. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam [Dept. of Radiation Oncology, Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Song, Jae Hoon [Dept. of Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Kim, Young Jae [Dept. of Radiological Technology, Gwang Yang Health Collage, Gwangyang (Korea, Republic of)

    2013-03-15

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam{sub t}ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule.

  17. Theory of oscillatory firing induced by spatially correlated noise and delayed inhibitory feedback

    Science.gov (United States)

    Lindner, Benjamin; Doiron, Brent; Longtin, André

    2005-12-01

    A network of leaky integrate-and-fire neurons with global inhibitory feedback and under the influence of spatially correlated noise is studied. We calculate the spectral statistics of the network (power spectrum of the population activity, cross spectrum between spike trains of different neurons) as well as of a single neuron (power spectrum of spike train, cross spectrum between external noise and spike train) within the network. As shown by comparison with numerical simulations, our theory works well for arbitrary network size if the feedback is weak and the amount of external noise does not exceed that of the internal noise. By means of our analytical results we discuss the quality of the correlation-induced oscillation in a large network as a function of the transmission delay and the internal noise intensity. It is shown that the strongest oscillation is obtained in a system with zero internal noise and adiabatically long delay (i.e., the delay period is longer than any other time scale in the system). For a neuron with a strong intrinsic frequency, the oscillation becomes strongly anharmonic in the case of a long delay time. We also discuss briefly the kind of synchrony introduced by the feedback-induced oscillation.

  18. Controlling chaos in a nonlinear pendulum using an extended time-delayed feedback control method

    Energy Technology Data Exchange (ETDEWEB)

    Souza de Paula, Aline [COPPE - Department of Mechanical Engineering, Universidade Federal do Rio de Janeiro, P.O. Box 68503, 21.941-972 Rio de Janeiro, RJ (Brazil)], E-mail: alinesp@ufrj.br; Savi, Marcelo Amorim [COPPE - Department of Mechanical Engineering, Universidade Federal do Rio de Janeiro, P.O. Box 68503, 21.941-972 Rio de Janeiro, RJ (Brazil)], E-mail: savi@mecanica.ufrj.br

    2009-12-15

    Chaos control is employed for the stabilization of unstable periodic orbits (UPOs) embedded in chaotic attractors. The extended time-delayed feedback control uses a continuous feedback loop incorporating information from previous states of the system in order to stabilize unstable orbits. This article deals with the chaos control of a nonlinear pendulum employing the extended time-delayed feedback control method. The control law leads to delay-differential equations (DDEs) that contain derivatives that depend on the solution of previous time instants. A fourth-order Runge-Kutta method with linear interpolation on the delayed variables is employed for numerical simulations of the DDEs and its initial function is estimated by a Taylor series expansion. During the learning stage, the UPOs are identified by the close-return method and control parameters are chosen for each desired UPO by defining situations where the largest Lyapunov exponent becomes negative. Analyses of a nonlinear pendulum are carried out by considering signals that are generated by numerical integration of the mathematical model using experimentally identified parameters. Results show the capability of the control procedure to stabilize UPOs of the dynamical system, highlighting some difficulties to achieve the stabilization of the desired orbit.

  19. Comments on multiple oscillatory solutions in systems with time-delay feedback

    Directory of Open Access Journals (Sweden)

    Michael Stich

    2015-11-01

    Full Text Available A complex Ginzburg-Landau equation subjected to local and global time-delay feedback terms is considered. In particular, multiple oscillatory solutions and their properties are studied. We present novel results regarding the disappearance of limit cycle solutions, derive analytical criteria for frequency degeneration, amplitude degeneration, and frequency extrema. Furthermore, we discuss the influence of the phase shift parameter and show analytically that the stabilization of the steady state and the decay of all oscillations (amplitude death cannot happen for global feedback only. Finally, we explain the onset of traveling wave patterns close to the regime of amplitude death.

  20. Dynamic Output Feedback Passive Control of Uncertain Switched Stochastic Systems with Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Huimei Jia

    2013-01-01

    Full Text Available This paper is concerned with the issues of passivity analysis and dynamic output feedback (DOF passive control for uncertain switched stochastic systems with time-varying delay via multiple storage functions (MSFs method. Firstly, based on the MSFs method, a sufficient condition for the existence of the passivity of the underlying system is established in terms of linear matrix inequalities (LMIs. Furthermore, the problem of dynamic output feedback passive control is investigated. Based on the obtained passivity condition, a sufficient condition for the existence of the desired switched passive controller is derived. Finally, a numerical example is presented to show the effectiveness of the proposed method.

  1. Memory State Feedback RMPC for Multiple Time-Delayed Uncertain Linear Systems with Input Constraints

    Directory of Open Access Journals (Sweden)

    Wei-Wei Qin

    2014-01-01

    Full Text Available This paper focuses on the problem of asymptotic stabilization for a class of discrete-time multiple time-delayed uncertain linear systems with input constraints. Then, based on the predictive control principle of receding horizon optimization, a delayed state dependent quadratic function is considered for incorporating MPC problem formulation. By developing a memory state feedback controller, the information of the delayed plant states can be taken into full consideration. The MPC problem is formulated to minimize the upper bound of infinite horizon cost that satisfies the sufficient conditions. Then, based on the Lyapunov-Krasovskii function, a delay-dependent sufficient condition in terms of linear matrix inequality (LMI can be derived to design a robust MPC algorithm. Finally, the digital simulation results prove availability of the proposed method.

  2. The fragility of intergroup relations: divergent effects of delayed audiovisual feedback in intergroup and intragroup interaction.

    Science.gov (United States)

    Pearson, Adam R; West, Tessa V; Dovidio, John F; Powers, Stacie Renfro; Buck, Ross; Henning, Robert

    2008-12-01

    Intergroup interactions between racial or ethnic majority and minority groups are often stressful for members of both groups; however, the dynamic processes that promote or alleviate tension in intergroup interaction remain poorly understood. Here we identify a behavioral mechanism-response delay-that can uniquely contribute to anxiety and promote disengagement from intergroup contact. Minimally acquainted White, Black, and Latino participants engaged in intergroup or intragroup dyadic conversation either in real time or with a subtle temporal disruption (1-s delay) in audiovisual feedback. Whereas intergroup dyads reported greater anxiety and less interest in contact after engaging in delayed conversation than after engaging in real-time conversation, intragroup dyads reported less anxiety in the delay condition than they did after interacting in real time. These findings have theoretical and practical implications for understanding intergroup communication and social dynamics and for promoting positive intergroup contact.

  3. Global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper presents both analytical and numerical studies on the global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback.Based on a detailed analysis of the stability switches of the trivial equilibrium of the system,the stability charts are given in a parameter space consisting of the time delay and the feedback gains.The center manifold reduc-tion and the normal form method are used to study Hopf bifurcations with respect to the time delay.To gain an insight into the persistence of a Hopf bifurcation as the time delay varies farther away from its critical value,the method of multiple scales is used to obtain the global view of Hopf bifurcations with respect to the time delay.Both the analytical results of Hopf bifurca-tions and global view of those bifurcations are validated via a collocation scheme implemented on DDE-Biftool.The most important discovery in this paper is the well-structured global view of Hopf bifurcations for the system of concern,showing the generality of the persistence of Hopf bifurcations.

  4. Bifurcation Analysis and Chaos Control in a Modified Finance System with Delayed Feedback

    Science.gov (United States)

    Yang, Jihua; Zhang, Erli; Liu, Mei

    2016-06-01

    We investigate the effect of delayed feedback on the finance system, which describes the time variation of the interest rate, for establishing the fiscal policy. By local stability analysis, we theoretically prove the existences of Hopf bifurcation and Hopf-zero bifurcation. By using the normal form method and center manifold theory, we determine the stability and direction of a bifurcating periodic solution. Finally, we give some numerical solutions, which indicate that when the delay passes through certain critical values, chaotic oscillation is converted into a stable equilibrium or periodic orbit.

  5. Stabilizability of linear quadratic state feedback for uncertain fuzzy time-delay systems.

    Science.gov (United States)

    Wang, Rong-Jyue; Lin, Wei-Wei; Wang, Wen-June

    2004-04-01

    This paper investigates the problem of designing a fuzzy state feedback controller to stabilize an uncertain fuzzy system with time-varying delay. Based on Lyapunov criterion and Razumikhin theorem, some sufficient conditions are derived under which the parallel-distributed fuzzy control can stabilize the whole uncertain fuzzy time-delay system asymptotically. By Schur complement, these sufficient conditions can be easily transformed into the problem of LMIs. Furthermore, the tolerable bound of the perturbation is also obtained. A practical example based on the continuous stirred tank reactor (CSTR) model is given to illustrate the control design and its effectiveness.

  6. Feedback control of time-delay systems with bounded control and state

    Directory of Open Access Journals (Sweden)

    M. Dambrine

    1995-01-01

    Full Text Available This paper is concerned with the problem of stabilizing linear time-delay systems under state and control linear constraints. For this, necessary and sufficient conditions for a given non-symmetrical polyhedral set to be positively invariant are obtained. Then existence conditions of linear state feedback control law respecting the constraints are established, and a procedure is given in order to calculate such a controller. The paper concerns memoryless controlled systems but the results can be applied to cases of delayed controlled systems. An example is given.

  7. Delayed resonator with acceleration feedback - Complete stability analysis by spectral methods and vibration absorber design

    Science.gov (United States)

    Vyhlídal, Tomáš; Olgac, Nejat; Kučera, Vladimír

    2014-12-01

    This paper deals with the problem of active vibration suppression using the concept of delayed resonator (DR) absorber with acceleration feedback. A complete dynamic analysis of DR and its coupling with a single degree of freedom mechanical system are performed. Due to the presence of a delay in the acceleration feedback, the dynamics of the resonator itself, as well as the dynamics of combined system are of ‘neutral' character. On this system, spectral methods are applied to perform a complete stability analysis. Particularly, the method of cluster treatment of characteristic roots is used to determine stability boundaries in the space of the resonator parameters. Based on this analysis, a methodology to select the resonator parameters is proposed in order to guarantee desirable suppression characteristics and to provide safe stability margins. An example case study is included to demonstrate these analytical results.

  8. Robust chaos synchronization based on adaptive fuzzy delayed feedback $\\mathcal{H}_{∞}$ control

    Indian Academy of Sciences (India)

    Choon Ki Ahn

    2012-03-01

    In this paper, we propose a new adaptive $\\mathcal_{∞}$ synchronization strategy, called an adaptive fuzzy delayed feedback $\\mathcal_{∞}$ synchronization (AFDFHS) strategy, for chaotic systems with uncertain parameters and external disturbances. Based on Lyapunov–Krasovskii theory, Takagi–Sugeno (T–S) fuzzy model and adaptive delayed feedback $\\mathcal_{∞}$ control scheme, the AFDFHS controller is presented such that the synchronization error system is asymptotically stable with a guaranteed $\\mathcal_{∞}$ performance. It is shown that the design of the AFDFHS controller with adaptive law can be achieved by solving a linear matrix inequality (LMI), which can be easily facilitated by using some standard numerical packages. An illustrative example is given to demonstrate the effectiveness of the proposed AFDFHS approach.

  9. Relation between the extended time-delayed feedback control algorithm and the method of harmonic oscillators.

    Science.gov (United States)

    Pyragas, Viktoras; Pyragas, Kestutis

    2015-08-01

    In a recent paper [Phys. Rev. E 91, 012920 (2015)] Olyaei and Wu have proposed a new chaos control method in which a target periodic orbit is approximated by a system of harmonic oscillators. We consider an application of such a controller to single-input single-output systems in the limit of an infinite number of oscillators. By evaluating the transfer function in this limit, we show that this controller transforms into the known extended time-delayed feedback controller. This finding gives rise to an approximate finite-dimensional theory of the extended time-delayed feedback control algorithm, which provides a simple method for estimating the leading Floquet exponents of controlled orbits. Numerical demonstrations are presented for the chaotic Rössler, Duffing, and Lorenz systems as well as the normal form of the Hopf bifurcation.

  10. Analysis of stability of a Power System by using Delay Static State Feedback

    Directory of Open Access Journals (Sweden)

    Sindy Paola Amaya

    2012-12-01

    Full Text Available This article presents the analysis of stability of a power system modeled as Infinite Bus Connected Generator with delay static state feedback. The model of the power system is described by nonlinear differential- algebraic equations. For controller design, we linealize the nonlinear differential-algebraic model around an operation point to obtain a lineal differential-algebraic model. As of this model obtains the Kronecker -Weierstrass model which designs the controller. To obtain the K gain of the controller outline inequalities matrix lineal (LMI's . Then it makes a study of the maximum delay that it supports in the state feedback. At the end of the article present the results and the conclusions.

  11. Global Practical Tracking by Output Feedback for Nonlinear Systems with Unknown Growth Rate and Time Delay

    Science.gov (United States)

    Yan, Xuehua

    2014-01-01

    This paper is the further investigation of work of Yan and Liu, 2011, and considers the global practical tracking problem by output feedback for a class of uncertain nonlinear systems with not only unmeasured states dependent growth but also time-varying time delay. Compared with the closely related works, the remarkableness of the paper is that the time-varying time delay and unmeasurable states are permitted in the system nonlinear growth. Motivated by the related tracking results and flexibly using the ideas and techniques of universal control and dead zone, an adaptive output-feedback tracking controller is explicitly designed with the help of a new Lyapunov-Krasovskii functional, to make the tracking error prescribed arbitrarily small after a finite time while keeping all the closed-loop signals bounded. A numerical example demonstrates the effectiveness of the results. PMID:25276859

  12. Pinning weighted complex networks with heterogeneous delays by a small number of feedback controllers

    Institute of Scientific and Technical Information of China (English)

    XIANG LinYing; LIU ZhongXin; CHEN ZengQiang; YUAN ZhuZhi

    2008-01-01

    Weighted complex dynamical networks with heterogeneous delays in both con-tinuous-time and discrete-time domains are controlled by applying local feedback injections to a small fraction of network nodes. Some generic stability criteria en-suring delay-independent stability are derived for such controlled networks in terms of linear matrix inequalities (LMIs), which guarantee that by placing a small number of feedback controllers on some nodes the whole network can be pinned to some desired homogenous states. In some particular cases, a single controller can achieve the control objective. It is found that stabilization of such pinned networks is completely determined by the dynamics of the individual uncoupled node, the overall coupling strength, the inner-coupling matrix, and the smallest eigenvalue of the coupling and control matrix. Numerical simulations of a weighted network composing of a 3-dimensional nonlinear system are finally given for illustration and verification.

  13. Time-delayed feedback control optimization for quasi linear systems under random excitations

    Institute of Scientific and Technical Information of China (English)

    Xueping Li; Detain Wei; Weiqiu Zhu

    2009-01-01

    A strategy for time-delayed feedback control optimization of quasi linear systems with random excita-tion is proposed. First, the stochastic averaging method is used to reduce the dimension of the state space and to derive the stationary response of the system. Secondly, the control law is assumed to be velocity feedback control with time delay and the unknown control gains are determined by the performance indices. The response of the controlled system is predicted through solving the Fokker-Plank-Kolmogorov equation associated with the averaged It6 equation. Finally, numerical examples are used to illustrate the proposed con-trol method, and the numerical results are confirmed by Monte Carlo simulation.

  14. Relation between the extended time-delayed feedback control algorithm and the method of harmonic oscillators

    Science.gov (United States)

    Pyragas, Viktoras; Pyragas, Kestutis

    2015-08-01

    In a recent paper [Phys. Rev. E 91, 012920 (2015), 10.1103/PhysRevE.91.012920] Olyaei and Wu have proposed a new chaos control method in which a target periodic orbit is approximated by a system of harmonic oscillators. We consider an application of such a controller to single-input single-output systems in the limit of an infinite number of oscillators. By evaluating the transfer function in this limit, we show that this controller transforms into the known extended time-delayed feedback controller. This finding gives rise to an approximate finite-dimensional theory of the extended time-delayed feedback control algorithm, which provides a simple method for estimating the leading Floquet exponents of controlled orbits. Numerical demonstrations are presented for the chaotic Rössler, Duffing, and Lorenz systems as well as the normal form of the Hopf bifurcation.

  15. Noise-induced attractor annihilation in the delayed feedback logistic map

    Energy Technology Data Exchange (ETDEWEB)

    Pisarchik, A.N., E-mail: apisarch@cio.mx [Centro de Investigaciones en Optica, Loma del Bosque 115, Leon, Guanajuato (Mexico); Centre for Biomedical Technology, Technical University of Madrid, Campus Montegancedo, 28223 Pozuelo de Alarcon, Madrid (Spain); Martínez-Zérega, B.E. [Centro Universitario de los Lagos, Universidad de Guadalajara, Enrique Diaz de Leon 1144, Paseos de la Montaña, Lagos de Moreno, Jalisco 47460 (Mexico)

    2013-12-06

    We study dynamics of the bistable logistic map with delayed feedback, under the influence of white Gaussian noise and periodic modulation applied to the variable. This system may serve as a model to describe population dynamics under finite resources in noisy environment with seasonal fluctuations. While a very small amount of noise has no effect on the global structure of the coexisting attractors in phase space, an intermediate noise totally eliminates one of the attractors. Slow periodic modulation enhances the attractor annihilation.

  16. Deterministic and stochastic control of chimera states in delayed feedback oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, V. [Department of Physics, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov (Russian Federation); Zakharova, A.; Schöll, E. [Institut für Theoretische Physik, TU Berlin, Hardenbergstraße 36, 10623 Berlin (Germany); Maistrenko, Y. [Institute of Mathematics and Center for Medical and Biotechnical Research, NAS of Ukraine, Tereschenkivska Str. 3, 01601 Kyiv (Ukraine)

    2016-06-08

    Chimera states, characterized by the coexistence of regular and chaotic dynamics, are found in a nonlinear oscillator model with negative time-delayed feedback. The control of these chimera states by external periodic forcing is demonstrated by numerical simulations. Both deterministic and stochastic external periodic forcing are considered. It is shown that multi-cluster chimeras can be achieved by adjusting the external forcing frequency to appropriate resonance conditions. The constructive role of noise in the formation of a chimera states is shown.

  17. Noise-Induced Phase Locking and Frequency Mixing in an Optical Bistable System with Delayed Feedback

    Science.gov (United States)

    Misono, Masatoshi; Miyakawa, Kenji

    2011-11-01

    The interplay between stochastic resonance (SR) and coherence resonance (CR) is experimentally studied in an optical bistable system with a time-delayed feedback loop. We demonstrate that the phase of the noise-induced motion is locked to that of the periodic input when the ratio of their frequencies is a simple rational number. We also demonstrate that the interplay between SR and CR generates frequency-mixed modes, and that the efficiency of frequency mixing is enhanced by the optimum noise.

  18. Fractal Erosion of the Safe Basin in a Helmholtz Oscillator and Its Control by Linear Delayed Velocity Feedback

    Institute of Scientific and Technical Information of China (English)

    SHANG Hui-Lin; WEN Yong-Peng

    2011-01-01

    Fractal erosion of the safe basin in a Helmholtz oscillator system is studied. A linear delayed velocity feedback is employed to suppress the fractal erosion. The necessary basin erosion condition of the delayed feedback controlled system is obtained. The evolution of the boundary and area of the safe basin over time delay is also presented. It follows that the delayed velocity feedback can be used as an effective strategy to control fractal erosion of a safe basin.%Fractal erosion of the safe basin in a Helmholtz oscillator system is studied.A linear delayed velocity feedback is employed to suppress the fractal erosion.The necessary basin erosion condition of the delayed feedback controlled system is obtained.The evolution of the boundary and area of the safe basin over time delay is also presented.It follows that the delayed velocity feedback can be used as an effective strategy to control fractal erosion of a safe basin.Since the safe basin was induced to explain the integrity of dynamical systems,studies on safe basins have attracted much attention.[1-6] Leigh and Armin calculated the survival probability of a ferry in random seas by estimating the erosion of the safe basin during the ship rolling motion by using Monte Carlo simulations.[1] Lenci and Rega induced the erosion of a safe basin to explain pull-in phenomenon in micro-electro mechanical systems.[2

  19. The Unresponsive Partner: Roles of Social Status, Auditory Feedback, and Animacy in Coordination of Joint Music Performance

    Science.gov (United States)

    Demos, Alexander P.; Carter, Daniel J.; Wanderley, Marcelo M.; Palmer, Caroline

    2017-01-01

    We examined temporal synchronization in joint music performance to determine how social status, auditory feedback, and animacy influence interpersonal coordination. A partner’s coordination can be bidirectional (partners adapt to the actions of one another) or unidirectional (one partner adapts). According to the dynamical systems framework, bidirectional coordination should be the optimal (preferred) state during live performance. To test this, 24 skilled pianists each performed with a confederate while their coordination was measured by the asynchrony in their tone onsets. To promote social balance, half of the participants were told the confederate was a fellow participant – an equal social status. To promote social imbalance, the other half was told the confederate was an experimenter – an unequal social status. In all conditions, the confederate’s arm and finger movements were occluded from the participant’s view to allow manipulation of animacy of the confederate’s performances (live or recorded). Unbeknownst to the participants, half of the confederate’s performances were replaced with pre-recordings, forcing the participant into unidirectional coordination during performance. The other half of the confederate’s performances were live, which permitted bidirectional coordination between performers. In a final manipulation, both performers heard the auditory feedback from one or both of the performers’ parts removed at unpredictable times to disrupt their performance. Consistently larger asynchronies were observed in performances of unidirectional (recorded) than bidirectional (live) performances across all conditions. Participants who were told the confederate was an experimenter reported their synchrony as more successful than when the partner was introduced as a fellow participant. Finally, asynchronies increased as auditory feedback was removed; removal of the confederate’s part hurt coordination more than removal of the participant

  20. The Unresponsive Partner: Roles of Social Status, Auditory Feedback, and Animacy in Coordination of Joint Music Performance.

    Science.gov (United States)

    Demos, Alexander P; Carter, Daniel J; Wanderley, Marcelo M; Palmer, Caroline

    2017-01-01

    We examined temporal synchronization in joint music performance to determine how social status, auditory feedback, and animacy influence interpersonal coordination. A partner's coordination can be bidirectional (partners adapt to the actions of one another) or unidirectional (one partner adapts). According to the dynamical systems framework, bidirectional coordination should be the optimal (preferred) state during live performance. To test this, 24 skilled pianists each performed with a confederate while their coordination was measured by the asynchrony in their tone onsets. To promote social balance, half of the participants were told the confederate was a fellow participant - an equal social status. To promote social imbalance, the other half was told the confederate was an experimenter - an unequal social status. In all conditions, the confederate's arm and finger movements were occluded from the participant's view to allow manipulation of animacy of the confederate's performances (live or recorded). Unbeknownst to the participants, half of the confederate's performances were replaced with pre-recordings, forcing the participant into unidirectional coordination during performance. The other half of the confederate's performances were live, which permitted bidirectional coordination between performers. In a final manipulation, both performers heard the auditory feedback from one or both of the performers' parts removed at unpredictable times to disrupt their performance. Consistently larger asynchronies were observed in performances of unidirectional (recorded) than bidirectional (live) performances across all conditions. Participants who were told the confederate was an experimenter reported their synchrony as more successful than when the partner was introduced as a fellow participant. Finally, asynchronies increased as auditory feedback was removed; removal of the confederate's part hurt coordination more than removal of the participant's part in live

  1. Adaptive Neural Control of MIMO Nonstrict-Feedback Nonlinear Systems With Time Delay.

    Science.gov (United States)

    Zhao, Xudong; Yang, Haijiao; Karimi, Hamid Reza; Zhu, Yanzheng

    2016-06-01

    In this paper, an adaptive neural output-feedback tracking controller is designed for a class of multiple-input and multiple-output nonstrict-feedback nonlinear systems with time delay. The system coefficient and uncertain functions of our considered systems are both unknown. By employing neural networks to approximate the unknown function entries, and constructing a new input-driven filter, a backstepping design method of tracking controller is developed for the systems under consideration. The proposed controller can guarantee that all the signals in the closed-loop systems are ultimately bounded, and the time-varying target signal can be tracked within a small error as well. The main contributions of this paper lie in that the systems under consideration are more general, and an effective design procedure of output-feedback controller is developed for the considered systems, which is more applicable in practice. Simulation results demonstrate the efficiency of the proposed algorithm.

  2. Chaos Generation and Synchronization Using Driven TWT amplifiers having delayed feedback

    Science.gov (United States)

    Larsen, P.; Booske, J. H.; Bhattacharjee, S.; Marchewka, C.; Sengele, S.; Koch, S.; Ryskin, N.; Titov, V.

    2004-11-01

    Development of high power sources of chaotic waveforms in the microwave frequency regime is important for communications, noise radar, and other applications. We have demonstrated that driven traveling wave tube (TWT) amplifiers with delayed feedback are excellent sources of chaotic radiation with numerous experimental advantages. The configuration involves a TWT oscillator (using an external feedback loop) which is driven by an external coherent generator. Two types of chaos have been observed in these experiments: a period doubling type and a "loss-of-synchronization" type of chaos. Characterizations have identified single frequency oscillation, self-modulation, and chaos within the parameter space defined by the drive power, drive frequency, and feedback attenuation level. Current investigations are examining synchronization between a pair of driven TWT oscillators.

  3. Bifurcation Control of an Electrostatically-Actuated MEMS Actuator with Time-Delay Feedback

    Directory of Open Access Journals (Sweden)

    Lei Li

    2016-10-01

    Full Text Available The parametric excitation system consisting of a flexible beam and shuttle mass widely exists in microelectromechanical systems (MEMS, which can exhibit rich nonlinear dynamic behaviors. This article aims to theoretically investigate the nonlinear jumping phenomena and bifurcation conditions of a class of electrostatically-driven MEMS actuators with a time-delay feedback controller. Considering the comb structure consisting of a flexible beam and shuttle mass, the partial differential governing equation is obtained with both the linear and cubic nonlinear parametric excitation. Then, the method of multiple scales is introduced to obtain a slow flow that is analyzed for stability and bifurcation. Results show that time-delay feedback can improve resonance frequency and stability of the system. What is more, through a detailed mathematical analysis, the discriminant of Hopf bifurcation is theoretically derived, and appropriate time-delay feedback force can make the branch from the Hopf bifurcation point stable under any driving voltage value. Meanwhile, through global bifurcation analysis and saddle node bifurcation analysis, theoretical expressions about the system parameter space and maximum amplitude of monostable vibration are deduced. It is found that the disappearance of the global bifurcation point means the emergence of monostable vibration. Finally, detailed numerical results confirm the analytical prediction.

  4. Pitchfork and Hopf bifurcation thresholds in stochastic equations with delayed feedback.

    Science.gov (United States)

    Gaudreault, Mathieu; Lépine, Françoise; Viñals, Jorge

    2009-12-01

    The bifurcation diagram of a model stochastic differential equation with delayed feedback is presented. We are motivated by recent research on stochastic effects in models of transcriptional gene regulation. We start from the normal form for a pitchfork bifurcation, and add multiplicative or parametric noise and linear delayed feedback. The latter is sufficient to originate a Hopf bifurcation in that region of parameters in which there is a sufficiently strong negative feedback. We find a sharp bifurcation in parameter space, and define the threshold as the point in which the stationary distribution function p(x) changes from a delta function at the trivial state x=0 to p(x) approximately x(alpha) at small x (with alpha=-1 exactly at threshold). We find that the bifurcation threshold is shifted by fluctuations relative to the deterministic limit by an amount that scales linearly with the noise intensity. Analytic calculations of the bifurcation threshold are also presented in the limit of small delay tau-->0 that compare quite favorably with the numerical solutions even for moderate values of tau .

  5. Principal resonance response of a stochastic elastic impact oscillator under nonlinear delayed state feedback

    Institute of Scientific and Technical Information of China (English)

    黄冬梅; 徐伟; 谢文贤; 韩群

    2015-01-01

    In this paper, the principal resonance response of a stochastically driven elastic impact (EI) system with time-delayed cubic velocity feedback is investigated. Firstly, based on the method of multiple scales, the steady-state response and its dynamic stability are analyzed in deterministic and stochastic cases, respectively. It is shown that for the case of the multi-valued response with the frequency island phenomenon, only the smallest amplitude of the steady-state response is stable under a certain time delay, which is different from the case of the traditional frequency response. Then, a design criterion is proposed to suppress the jump phenomenon, which is induced by the saddle-node bifurcation. The effects of the feedback parameters on the steady-state responses, as well as the size, shape, and location of stability regions are studied. Results show that the system responses and the stability boundaries are highly dependent on these parameters. Furthermore, with the purpose of suppressing the amplitude peak and governing the resonance stability, appropriate feedback gain and time delay are derived.

  6. Global stabilisation for a class of uncertain nonlinear time-delay systems by dynamic state and output feedback

    Science.gov (United States)

    Chai, Lin; Qian, Chunjiang

    2015-06-01

    This paper investigates the design problem of constructing the state and output feedback stabilisation controller for a class of uncertain nonlinear systems subject to time-delay. First, a dynamic linear state feedback control law with an adaptive strategy is developed to globally stabilise the uncertain nonlinear time-delay system under a lower-triangular higher-order growth condition. Then, one more challenging problem of the adaptive output feedback stabilisation is addressed, which can globally stabilise the time-delay system when the unmeasurable states linearly grow with rate functions consisting of higher-order output.

  7. Observer-based output feedback control of discrete-time linear systems with input and output delays

    Science.gov (United States)

    Zhou, Bin

    2014-11-01

    In this paper, we study observer-based output feedback control of discrete-time linear systems with both multiple input and output delays. By generalising our recently developed truncated predictor feedback approach for state feedback stabilisation of discrete-time time-delay systems to the design of observer-based output feedback, two types of observer-based output feedback controllers, one being memory and the other memoryless, are constructed. Both full-order and reduced-order observer-based controllers are established in both the memory and memoryless schemes. It is shown that the separation principle holds for the memory observer-based output feedback controllers, but does not hold for the memoryless ones. We further show that the proposed observer-based output feedback controllers solve both the l2 and l∞ semi-global stabilisation problems. A numerical example is given to illustrate the effectiveness of the proposed approaches.

  8. Short-term delayed recall of auditory verbal learning test is equivalent to long-term delayed recall for identifying amnestic mild cognitive impairment.

    Directory of Open Access Journals (Sweden)

    Qianhua Zhao

    Full Text Available Delayed recall of words in a verbal learning test is a sensitive measure for the diagnosis of amnestic mild cognitive impairment (aMCI and early Alzheimer's disease (AD. The relative validity of different retention intervals of delayed recall has not been well characterized. Using the Auditory Verbal Learning Test-Huashan version, we compared the differentiating value of short-term delayed recall (AVL-SR, that is, a 3- to 5-minute delay time and long-term delayed recall (AVL-LR, that is, a 20-minute delay time in distinguishing patients with aMCI (n = 897 and mild AD (n = 530 from the healthy elderly (n = 1215. In patients with aMCI, the correlation between AVL-SR and AVL-LR was very high (r = 0.94, and the difference between the two indicators was less than 0.5 points. There was no difference between AVL-SR and AVL-LR in the frequency of zero scores. In the receiver operating characteristic curves analysis, although the area under the curve (AUC of AVL-SR and AVL-LR for diagnosing aMCI was significantly different, the cut-off scores of the two indicators were identical. In the subgroup of ages 80 to 89, the AUC of the two indicators showed no significant difference. Therefore, we concluded that AVL-SR could substitute for AVL-LR in identifying aMCI, especially for the oldest patients.

  9. Bifurcation analysis of a semiconductor laser with saturable absorber and delayed optical feedback

    CERN Document Server

    Terrien, Soizic; Broderick, Neil G R

    2016-01-01

    Semiconductor lasers exhibit a wealth of dynamics, from emission of a constant beam of light, to periodic oscillations and excitability. Self-pulsing regimes, where the laser periodically releases a short pulse of light, are particularly interesting for many applications, from material science to telecommunications. Self-pulsing regimes need to produce pulses very regularly and, as such, they are also known to be particularly sensitive to perturbations, such as noise or light injection. We investigate the effect of delayed optical feedback on the dynamics of a self-pulsing semiconductor laser with saturable absorber (SLSA). More precisely, we consider the Yamada model with delay -- a system of three delay-differential equations (DDEs) for two slow and one fast variable -- which has been shown to reproduce accurately self-pulsing features as observed in SLSA experimentally. This model is also of broader interest because it is quite closely related to mathematical models of other self-pulsing systems, such as e...

  10. Adaptive Output-feedback Regulation for Nonlinear Delayed Systems Using Neural Network

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel adaptive neural network (NN) output-feedback regulation algorithm for a class of nonlinear time-varying time-delay systems is proposed. Both the designed observer and controller are independent of time delay. Different from the existing results,where the upper bounding functions of time-delay terms are assumed to be known, we only use an NN to compensate for all unknown upper bounding functions without that assumption. The proposed design method is proved to be able to guarantee semi-global uniform ultimate boundedness of all the signals in the closed system, and the system output is proved to converge to a small neighborhood of the origin. The simulation results verify the effectiveness of the control scheme.

  11. A do-it-yourself membrane-activated auditory feedback device for weight bearing and gait training: a case report.

    Science.gov (United States)

    Batavia, M; Gianutsos, J G; Vaccaro, A; Gold, J T

    2001-04-01

    An augmented auditory feedback device comprised of a thin membrane switch mini-buzzer, and battery is described as a modification of a previously described feedback device. The membrane switch can be customized for the patient and is designed to fit inside a patient's shoe without altering the heel height. Its appeal lies in its simplicity of construction, low cost, and ease of implementation during a patient's training for weight bearing and gait. An ever-present source of information, it provides performance-relevant cues to both patient and clinician about the occurrence, duration, and location of a force component of motor performance. The report includes suggested applications of the device, instructions to construct it, and a case report in which the device was used to improve weight bearing and gait in a cognitively healthy person with spina bifida.

  12. Effects of delay and noise in a negative feedback regulatory motif

    Science.gov (United States)

    Palassini, Matteo; Dies, Marta

    2009-03-01

    The small copy number of the molecules involved in gene regulation can induce nontrivial stochastic phenomena such as noise-induced oscillations. An often neglected aspect of regulation dynamics are the delays involved in transcription and translation. Delays introduce analytical and computational complications because the dynamics is non-Markovian. We study the interplay of noise and delays in a negative feedback model of the p53 core regulatory network. Recent experiments have found pronounced oscillations in the concentrations of proteins p53 and Mdm2 in individual cells subjected to DNA damage. Similar oscillations occur in the Hes-1 and NK-kB systems, and in circadian rhythms. Several mechanisms have been proposed to explain this oscillatory behaviour, such as deterministic limit cycles, with and without delay, or noise-induced excursions in excitable models. We consider a generic delayed Master Equation incorporating the activation of Mdm2 by p53 and the Mdm2-promoted degradation of p53. In the deterministic limit and for large delays, the model shows a Hopf bifurcation. Via exact stochastic simulations, we find strong noise-induced oscillations well outside the limit-cycle region. We propose that this may be a generic mechanism for oscillations in gene regulatory systems.

  13. Evaluating feedback time delay during perturbed and unperturbed balance in handstand.

    Science.gov (United States)

    Blenkinsop, Glen M; Pain, Matthew T G; Hiley, Michael J

    2016-08-01

    Feedback delays in balance are often assessed using muscle activity onset latencies in response to discrete perturbations. The purpose of the study was to calculate EMG latencies in perturbed handstand, and determine if delays are different to unperturbed handstand. Twelve national level gymnasts completed 12 perturbed and 10 unperturbed (five eyes open and five closed) handstands. Forearm EMG latencies during perturbed handstands were assessed against delay estimates calculated via: cross correlations of wrist torque and COM displacement, a proportional and derivative model of wrist torque and COM displacement and velocity (PD model), and a PD model incorporating a passive stiffness component (PS-PD model). Delays from the PD model (161±14ms) and PS-PD model (188±14ms) were in agreement with EMG latencies (165±14ms). Cross correlations of COM displacement and wrist torque provided unrealistically low estimates (5±9ms). Delays were significantly lower during perturbed (188±14ms) compared to unperturbed handstand (eyes open: 207±12ms; eyes closed: 220±19ms). Significant differences in delays and model parameters between perturbed and unperturbed handstand support the view that balance measures in perturbed testing should not be generalised to unperturbed balance.

  14. Incentives for Delay-Constrained Data Query and Feedback in Mobile Opportunistic Crowdsensing

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-07-01

    Full Text Available In this paper, we propose effective data collection schemes that stimulate cooperation between selfish users in mobile opportunistic crowdsensing. A query issuer generates a query and requests replies within a given delay budget. When a data provider receives the query for the first time from an intermediate user, the former replies to it and authorizes the latter as the owner of the reply. Different data providers can reply to the same query. When a user that owns a reply meets the query issuer that generates the query, it requests the query issuer to pay credits. The query issuer pays credits and provides feedback to the data provider, which gives the reply. When a user that carries a feedback meets the data provider, the data provider pays credits to the user in order to adjust its claimed expertise. Queries, replies and feedbacks can be traded between mobile users. We propose an effective mechanism to define rewards for queries, replies and feedbacks. We formulate the bargain process as a two-person cooperative game, whose solution is found by using the Nash theorem. To improve the credit circulation, we design an online auction process, in which the wealthy user can buy replies and feedbacks from the starving one using credits. We have carried out extensive simulations based on real-world traces to evaluate the proposed schemes.

  15. Incentives for Delay-Constrained Data Query and Feedback in Mobile Opportunistic Crowdsensing

    Science.gov (United States)

    Liu, Yang; Li, Fan; Wang, Yu

    2016-01-01

    In this paper, we propose effective data collection schemes that stimulate cooperation between selfish users in mobile opportunistic crowdsensing. A query issuer generates a query and requests replies within a given delay budget. When a data provider receives the query for the first time from an intermediate user, the former replies to it and authorizes the latter as the owner of the reply. Different data providers can reply to the same query. When a user that owns a reply meets the query issuer that generates the query, it requests the query issuer to pay credits. The query issuer pays credits and provides feedback to the data provider, which gives the reply. When a user that carries a feedback meets the data provider, the data provider pays credits to the user in order to adjust its claimed expertise. Queries, replies and feedbacks can be traded between mobile users. We propose an effective mechanism to define rewards for queries, replies and feedbacks. We formulate the bargain process as a two-person cooperative game, whose solution is found by using the Nash theorem. To improve the credit circulation, we design an online auction process, in which the wealthy user can buy replies and feedbacks from the starving one using credits. We have carried out extensive simulations based on real-world traces to evaluate the proposed schemes. PMID:27455261

  16. Logarithmic temporal axis manipulation and its application for measuring auditory contributions in F0 control using a transformed auditory feedback procedure

    Science.gov (United States)

    Yanaga, Ryuichiro; Kawahara, Hideki

    2003-10-01

    A new parameter extraction procedure based on logarithmic transformation of the temporal axis was applied to investigate auditory effects on voice F0 control to overcome artifacts due to natural fluctuations and nonlinearities in speech production mechanisms. The proposed method may add complementary information to recent findings reported by using frequency shift feedback method [Burnett and Larson, J. Acoust. Soc. Am. 112 (2002)], in terms of dynamic aspects of F0 control. In a series of experiments, dependencies of system parameters in F0 control on subjects, F0 and style (musical expressions and speaking) were tested using six participants. They were three male and three female students specialized in musical education. They were asked to sustain a Japanese vowel /a/ for about 10 s repeatedly up to 2 min in total while hearing F0 modulated feedback speech, that was modulated using an M-sequence. The results replicated qualitatively the previous finding [Kawahara and Williams, Vocal Fold Physiology, (1995)] and provided more accurate estimates. Relations with designing an artificial singer also will be discussed. [Work partly supported by the grant in aids in scientific research (B) 14380165 and Wakayama University.

  17. Controlling traffic jams on a two-lane road using delayed-feedback signals

    Institute of Scientific and Technical Information of China (English)

    Liang ZHENG; Shi-quan ZHONG; Shou-feng MA

    2012-01-01

    This paper focuses mainly on the stability analysis of two-lane traffic flow with lateral friction,which may be caused by irregular driving behavior or poorly visible road markings,and also attempts to reveal the formation mechanism of traffic jams.Firstly,a two-lane optimal velocity (OV) model without control signals is proposed and its stability condition is obtained from the viewpoint of control theory.Then delayed-feedback control signals composed of distance headway information from both lanes are added to each vehicle and a vehicular control system is designed to suppress the traffic jams.Lane change behaviors are also incorporated into the two-lane OV model and the corresponding information about distance headway and feedback signals is revised.Finally,the results of numerical experiments are shown to verify that when the stability condition is not met,the position disturbances and resulting lane change behaviors do indeed deteriorate traffic performance and cause serious traffic jams.However,once the proper delayed-feedback control signals are implemented,the traffic jams can be suppressed efficiently.

  18. Identification and characterization of systems with delayed feedback; 1, Theory and tools

    CERN Document Server

    Bünner, M J; Giaquinta, A; Hegger, R; Kantz, H; Meucci, R; Politi, A; Bünner, Martin J.; Ciofini, Marco; Giaquinta, Antonino; Hegger, Rainer; Kantz, Holger; Meucci, Riccardo; Politi, Antonio

    1999-01-01

    High-dimensional chaos displayed by multi-component systems with a single time-delayed feedback is shown to be accessible to time series analysis of a scalar variable only. The mapping of the original dynamics onto scalar time-delay systems defined on sufficiently high dimensional spaces is thoroughly discussed. The dimension of the ``embedding'' space turns out to be independent of the delay time and thus of the dimensionality of the attractor dynamics. As a consequence, the procedure described in the present paper turns out to be definitely advantageous with respect to the standard ``embedding'' technique in the case of high-dimensional chaos, when the latter is practically unapplicable. The mapping is not exact when delayed maps are used to reproduce the dynamics of time-continuous systems, but the errors can be kept under control. In this context, the approximation of delay-differential equations is discussed with reference to different classes of maps. Appropriate tools to estimate the a priori unknown d...

  19. Permanence of a Nicholson’s Blowflies Model with Feedback Control and Multiple Time-varying Delays

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-ying; SHI Chun-ling

    2015-01-01

    This paper covers the dynamic behaviors for a class of Nicholson’s blowflies model with multiple time-varying delay and feedback control. By using the dierential inequality theory, a set of sucient conditions are obtained to ensure the permanence of the system. Our result shows that feedback control variables have no influence on the permanence of the system.

  20. Stimulus-locked responses of two phase oscillators coupled with delayed feedback

    Science.gov (United States)

    Krachkovskyi, Valerii; Popovych, Oleksandr V.; Tass, Peter A.

    2006-06-01

    For a system of two phase oscillators coupled with delayed self-feedback we study the impact of pulsatile stimulation administered to both oscillators. This system models the dynamics of two coupled phase-locked loops (PLLs) with a finite internal delay within each loop. The delayed self-feedback leads to a rich variety of dynamical regimes, ranging from phase-locked and periodically modulated synchronized states to chaotic phase synchronization and desynchronization. Remarkably, for large coupling strength the two PLLs are completely desynchronized. We study stimulus-locked responses emerging in the different dynamical regimes. Simple phase resets may be followed by a response clustering, which is intimately connected with long poststimulus resynchronization. Intriguingly, a maximal perturbation (i.e., maximal response clustering and maximal resynchronization time) occurs, if the system gets trapped at a stable manifold of an unstable saddle fixed point due to appropriately calibrated stimulus. Also, single stimuli with suitable parameters can shift the system from a stable synchronized state to a stable desynchronized state or vice versa. Our result show that appropriately calibrated single pulse stimuli may cause pronounced transient and/or long-lasting changes of the oscillators’ dynamics. Pulse stimulation may, hence, constitute an effective approach for the control of coupled oscillators, which might be relevant to both physical and medical applications.

  1. Adaptive Neural Control of Pure-Feedback Nonlinear Time-Delay Systems via Dynamic Surface Technique.

    Science.gov (United States)

    Min Wang; Xiaoping Liu; Peng Shi

    2011-12-01

    This paper is concerned with robust stabilization problem for a class of nonaffine pure-feedback systems with unknown time-delay functions and perturbed uncertainties. Novel continuous packaged functions are introduced in advance to remove unknown nonlinear terms deduced from perturbed uncertainties and unknown time-delay functions, which avoids the functions with control law to be approximated by radial basis function (RBF) neural networks. This technique combining implicit function and mean value theorems overcomes the difficulty in controlling the nonaffine pure-feedback systems. Dynamic surface control (DSC) is used to avoid "the explosion of complexity" in the backstepping design. Design difficulties from unknown time-delay functions are overcome using the function separation technique, the Lyapunov-Krasovskii functionals, and the desirable property of hyperbolic tangent functions. RBF neural networks are employed to approximate desired virtual controls and desired practical control. Under the proposed adaptive neural DSC, the number of adaptive parameters required is reduced significantly, and semiglobal uniform ultimate boundedness of all of the signals in the closed-loop system is guaranteed. Simulation studies are given to demonstrate the effectiveness of the proposed design scheme.

  2. Stimulus-locked responses of two phase oscillators coupled with delayed feedback.

    Science.gov (United States)

    Krachkovskyi, Valerii; Popovych, Oleksandr V; Tass, Peter A

    2006-06-01

    For a system of two phase oscillators coupled with delayed self-feedback we study the impact of pulsatile stimulation administered to both oscillators. This system models the dynamics of two coupled phase-locked loops (PLLs) with a finite internal delay within each loop. The delayed self-feedback leads to a rich variety of dynamical regimes, ranging from phase-locked and periodically modulated synchronized states to chaotic phase synchronization and desynchronization. Remarkably, for large coupling strength the two PLLs are completely desynchronized. We study stimulus-locked responses emerging in the different dynamical regimes. Simple phase resets may be followed by a response clustering, which is intimately connected with long poststimulus resynchronization. Intriguingly, a maximal perturbation (i.e., maximal response clustering and maximal resynchronization time) occurs, if the system gets trapped at a stable manifold of an unstable saddle fixed point due to appropriately calibrated stimulus. Also, single stimuli with suitable parameters can shift the system from a stable synchronized state to a stable desynchronized state or vice versa. Our result show that appropriately calibrated single pulse stimuli may cause pronounced transient and/or long-lasting changes of the oscillators' dynamics. Pulse stimulation may, hence, constitute an effective approach for the control of coupled oscillators, which might be relevant to both physical and medical applications.

  3. Adaptive Output Feedback Sliding Mode Control for Complex Interconnected Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Van Van Huynh

    2015-01-01

    Full Text Available We extend the decentralized output feedback sliding mode control (SMC scheme to stabilize a class of complex interconnected time-delay systems. First, sufficient conditions in terms of linear matrix inequalities are derived such that the equivalent reduced-order system in the sliding mode is asymptotically stable. Second, based on a new lemma, a decentralized adaptive sliding mode controller is designed to guarantee the finite time reachability of the system states by using output feedback only. The advantage of the proposed method is that two major assumptions, which are required in most existing SMC approaches, are both released. These assumptions are (1 disturbances are bounded by a known function of outputs and (2 the sliding matrix satisfies a matrix equation that guarantees the sliding mode. Finally, a numerical example is used to demonstrate the efficacy of the method.

  4. The predictability of frequency-altered auditory feedback changes the weighting of feedback and feedforward input for speech motor control.

    Science.gov (United States)

    Scheerer, Nichole E; Jones, Jeffery A

    2014-12-01

    Speech production requires the combined effort of a feedback control system driven by sensory feedback, and a feedforward control system driven by internal models. However, the factors that dictate the relative weighting of these feedback and feedforward control systems are unclear. In this event-related potential (ERP) study, participants produced vocalisations while being exposed to blocks of frequency-altered feedback (FAF) perturbations that were either predictable in magnitude (consistently either 50 or 100 cents) or unpredictable in magnitude (50- and 100-cent perturbations varying randomly within each vocalisation). Vocal and P1-N1-P2 ERP responses revealed decreases in the magnitude and trial-to-trial variability of vocal responses, smaller N1 amplitudes, and shorter vocal, P1 and N1 response latencies following predictable FAF perturbation magnitudes. In addition, vocal response magnitudes correlated with N1 amplitudes, vocal response latencies, and P2 latencies. This pattern of results suggests that after repeated exposure to predictable FAF perturbations, the contribution of the feedforward control system increases. Examination of the presentation order of the FAF perturbations revealed smaller compensatory responses, smaller P1 and P2 amplitudes, and shorter N1 latencies when the block of predictable 100-cent perturbations occurred prior to the block of predictable 50-cent perturbations. These results suggest that exposure to large perturbations modulates responses to subsequent perturbations of equal or smaller size. Similarly, exposure to a 100-cent perturbation prior to a 50-cent perturbation within a vocalisation decreased the magnitude of vocal and N1 responses, but increased P1 and P2 latencies. Thus, exposure to a single perturbation can affect responses to subsequent perturbations.

  5. The Effects of Constant Time Delay and Instructive Feedback on the Acquisition of English and Spanish Sight Words

    Science.gov (United States)

    Appelman, Michelle; Vail, Cynthia O.; Lieberman-Betz, Rebecca G.

    2014-01-01

    The authors of this study evaluated the acquisition of instructive feedback information presented to four kindergarten children with mild delays taught in dyads using a constant time delay (CTD) procedure. They also assessed the learning of observational (dyadic partner) information within this instructional arrangement. A multiple probe design…

  6. Decentralized H∞ state feedback control for large-scale interconnected uncertain systems with multiple delays

    Institute of Scientific and Technical Information of China (English)

    陈宁; 桂卫华; 谢永芳

    2004-01-01

    Decentralized H∞ control was studied for a class of interconnected uncertain systems with multiple delays in the state and control and time varying but norm-bounded parametric uncertainties. A sufficient condition which makes the closed--loop system decentralized asymptotically stable with H∞ performance was derived based on Lyapunov stability theorem. This condition is expressed as the solvability problem of linear matrix inequalities. The method overcomes the limitations of the existing algebraic Riccati equation method. Finally, a numerical example was given to demonstrate the design procedure for the decentralized H∞ state feedback controller.

  7. Shape, smoothness and invariant stratification of an attracting set for delayed monotone positive feedback

    CERN Document Server

    Krisztin, Tibor; Wu, Jianhong

    1998-01-01

    This book contains recent results about the global dynamics defined by a class of delay differential equations which model basic feedback mechanisms and arise in a variety of applications such as neural networks. The authors describe in detail the geometric structure of a fundamental invariant set, which in special cases is the global attractor, and the asymptotic behavior of solution curves on it. The approach makes use of advanced tools which in recent years have been developed for the investigation of infinite-dimensional dynamical systems: local invariant manifolds and inclination lemmas f

  8. Adaptive neural control for a class of perturbed strict-feedback nonlinear time-delay systems.

    Science.gov (United States)

    Wang, Min; Chen, Bing; Shi, Peng

    2008-06-01

    This paper proposes a novel adaptive neural control scheme for a class of perturbed strict-feedback nonlinear time-delay systems with unknown virtual control coefficients. Based on the radial basis function neural network online approximation capability, an adaptive neural controller is presented by combining the backstepping approach and Lyapunov-Krasovskii functionals. The proposed controller guarantees the semiglobal boundedness of all the signals in the closed-loop system and contains minimal learning parameters. Finally, three simulation examples are given to demonstrate the effectiveness and applicability of the proposed scheme.

  9. Theoretical and experimental aspects of chaos control by time-delayed feedback.

    Science.gov (United States)

    Just, Wolfram; Benner, Hartmut; Reibold, Ekkehard

    2003-03-01

    We review recent developments for the control of chaos by time-delayed feedback methods. While such methods are easily applied even in quite complex experimental context the theoretical analysis yields infinite-dimensional differential-difference systems which are hard to tackle. The essential ideas for a general theoretical approach are sketched and the results are compared to electronic circuits and to high power ferromagnetic resonance experiments. Our results show that the control performance can be understood on the basis of experimentally accessible quantities without resort to any model for the internal dynamics.

  10. Delayed Feedback Control of Bao Chaotic System Based on Hopf Bifurcation Analysis

    Directory of Open Access Journals (Sweden)

    Farhad Khellat

    2014-11-01

    Full Text Available This paper is concerned with bifurcation and chaos control in a new chaotic system recently introduced by Bao et al [9]. First a condition that the system has a Hopf bifurcation is derived. Then by applying delayed feedback controller, the chaotic system is forced to have a stable periodic orbit extracting from chaotic attractor. This is done by making Hopf bifurcation value of the open loop and the closed loop systems identical. Also by suitable tuning of the controller parameters, unstable equilibrium points become stable. Numerical simulations verify the results.

  11. Self-Injection-Locked Magnetron as an Active Ring Resonator Side Coupled to a Waveguide With a Delayed Feedback Loop

    Science.gov (United States)

    Bliokh, Y. P.; Krasik, Y. E.; Felsteiner, J.

    2012-01-01

    The theoretical analysis and numerical simulations of the magnetron operation with a feedback loop were performed assuming that the delay of the electromagnetic wave propagating in the loop is constant whereas the phase of the complex feedback reflection coefficient is varied. Results of simulations showed that by a proper adjustment of values of the time delay and phase of reflection coefficient that determines phase matching between the waves in the resonator and feedback loop, one can increase the magnetron's output power significantly without any other additional measures.

  12. Self-injection-locked magnetron as an active ring resonator side coupled to a waveguide with a delayed feedback loop

    CERN Document Server

    Bliokh, Y P; Felsteiner, J

    2011-01-01

    The theoretical analysis and numerical simulations of the magnetron operation with a feedback loop were performed assuming that the delay of the electromagnetic wave propagating in the loop is constant whereas the phase of the complex feedback reflection coefficient is varied. Results of simulations showed that by a proper adjustment of values of the time delay and phase of reflection coefficient that determines phase matching between the waves in the resonator and feedback loop, one can increase the magnetron's output power significantly without any other additional measures.

  13. Decentralized adaptive fuzzy output feedback control of nonlinear interconnected systems with time-varying delay

    Science.gov (United States)

    Wang, Qin; Chen, Zuwen; Song, Aiguo

    2017-01-01

    A robust adaptive output-feedback control scheme based on K-filters is proposed for a class of nonlinear interconnected time-varying delay systems with immeasurable states. It is difficult to design the controller due to the existence of the immeasurable states and the time-delay couplings among interconnected subsystems. This difficulty is overcome by use of the fuzzy system, the K-filters and the appropriate Lyapunov-Krasovskii functional. Based on Lyapunov theory, the closed-loop control system is proved to be semi-global uniformly ultimately bounded (SGUUB), and the output tracking error converges to a neighborhood of zero. Simulation results demonstrate the effectiveness of the approach.

  14. Internet based gripper teleoperation with random time delay by using haptic feedback and SEMG

    Science.gov (United States)

    Xu, Xiaonong; Song, Aiguo; Zhang, Huatao; Ji, Peng

    2016-10-01

    Random time delay may cause instability in the internet based teleoperation system. Transparency and intuitiveness are also very important for operator to control the system to accurately perform the desired action, especially for the gripper teleoperation system. This paper presents a new grip force control method of gripper teleoperation system with haptic feedback. The system employs the SEMG signal as the control parameter in order to enhance the intuitive control experience for operator. In order to eliminate the impacts on the system stability caused by random time delay, a non-time based teleoperation method is applied to the control process. Besides, neural network and designed fuzzy logic controller is also utilized to improve this control method. The effectiveness of the proposed method is demonstrated by experiment results.

  15. Adaptive Fuzzy Control of Strict-Feedback Nonlinear Time-Delay Systems With Unmodeled Dynamics.

    Science.gov (United States)

    Yin, Shen; Shi, Peng; Yang, Hongyan

    2016-08-01

    In this paper, an approximated-based adaptive fuzzy control approach with only one adaptive parameter is presented for a class of single input single output strict-feedback nonlinear systems in order to deal with phenomena like nonlinear uncertainties, unmodeled dynamics, dynamic disturbances, and unknown time delays. Lyapunov-Krasovskii function approach is employed to compensate the unknown time delays in the design procedure. By combining the advances of the hyperbolic tangent function with adaptive fuzzy backstepping technique, the proposed controller guarantees the semi-globally uniformly ultimately boundedness of all the signals in the closed-loop system from the mean square point of view. Two simulation examples are finally provided to show the superior effectiveness of the proposed scheme.

  16. Stability of PID-Controlled Linear Time-Delay Feedback Systems

    CERN Document Server

    Martelli, Gianpasquale

    2008-01-01

    The stability of feedback systems consisting of linear time-delay plants and PID controllers has been investigated for many years by means of several methods, of which the Nyquist criterion, a generalization of the Hermite-Biehler Theorem, and the root location method are well known. The main purpose of these researches is to determine the range of controller parameters that allow stability. Explicit and complete expressions of the boundaries of these regions and computation procedures with a finite number of steps are now available only for first-order plants, provided with one time delay. In this note, the same results, based on Pontryagin's studies, are presented for arbitrary-order plants.

  17. Desynchronization in an ensemble of globally coupled chaotic bursting neuronal oscillators by dynamic delayed feedback control

    CERN Document Server

    Che, Yanqiu; Li, Ruixue; Li, Huiyan; Han, Chunxiao; Wang, Jiang; Wei, Xile

    2014-01-01

    In this paper, we propose a dynamic delayed feedback control approach for desynchronization of chaotic-bursting synchronous activities in an ensemble of globally coupled neuronal oscillators. We demonstrate that the difference signal between an ensemble's mean field and its time delayed state, filtered and fed back to the ensemble, can suppress the self-synchronization in the ensemble. These individual units are decoupled and stabilized at the desired desynchronized states while the stimulation signal reduces to the noise level. The effectiveness of the method is illustrated by examples of two different populations of globally coupled chaotic-bursting neurons. The proposed method has potential for mild, effective and demand-controlled therapy of neurological diseases characterized by pathological synchronization.

  18. Anticontrol of chaos in continuous-time systems via time-delay feedback.

    Science.gov (United States)

    Wang, Xiao Fan; Chen, Guanrong; Yu, Xinghuo

    2000-12-01

    In this paper, a systematic design approach based on time-delay feedback is developed for anticontrol of chaos in a continuous-time system. This anticontrol method can drive a finite-dimensional, continuous-time, autonomous system from nonchaotic to chaotic, and can also enhance the existing chaos of an originally chaotic system. Asymptotic analysis is used to establish an approximate relationship between a time-delay differential equation and a discrete map. Anticontrol of chaos is then accomplished based on this relationship and the differential-geometry control theory. Several examples are given to verify the effectiveness of the methodology and to illustrate the systematic design procedure. (c) 2000 American Institute of Physics.

  19. Correlation times in stochastic equations with delayed feedback and multiplicative noise.

    Science.gov (United States)

    Gaudreault, Mathieu; Berbert, Juliana Militão; Viñals, Jorge

    2011-01-01

    We obtain the characteristic correlation time associated with a model stochastic differential equation that includes the normal form of a pitchfork bifurcation and delayed feedback. In particular, the validity of the common assumption of statistical independence between the state at time t and that at t-τ, where τ is the delay time, is examined. We find that the correlation time diverges at the model's bifurcation line, thus signaling a sharp bifurcation threshold, and the failure of statistical independence near threshold. We determine the correlation time both by numerical integration of the governing equation, and analytically in the limit of small τ. The correlation time T diverges as T~a(-1), where a is the control parameter so that a=0 is the bifurcation threshold. The small-τ expansion correctly predicts the location of the bifurcation threshold, but there are systematic deviations in the magnitude of the correlation time.

  20. Robust H∞ control for uncertain systems with heterogeneous time-varying delays via static output feedback

    Institute of Scientific and Technical Information of China (English)

    Wang Jun-Wei; Zeng Cai-Bin

    2012-01-01

    This paper is concerned with the problem of robust H∞ control for a novel class of uncertain linear continuous-time systems with heterogeneous time-varying state/input delays and norm-bounded parameter uncertainties.The objective is to design a static output feedback controller such that the closed-loop system is asymptotically stable while satisfying a prescribed H∞ performance level for all admissible uncertainties.By constructing an appropriate Lyapunov-Krasvskii functional,a delay-dependent stability criterion of the closed-loop system is presented with the help of the Jensen integral inequality.From the derived criterion,the solutions to the problem are formulated in terms of linear matrix inequalities and hence are tractable numerically.A simulation example is given to illustrate the effectiveness of the proposed design method.

  1. Exponential synchronization of general chaotic delayed neural networks via hybrid feedback

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper investigates the exponential synchronization problem of some chaotic delayed neural networks based on the proposed general neural network model, which is the interconnection of a linear delayed dynamic system and a bounded static nonlinear operator, and covers several well-known neural networks, such as Hopfield neural networks, cellular neural networks (CNNs), bidirectional associative memory (BAM) networks, recurrent multilayer perceptrons (RMLPs). By virtue of LyapunovKrasovskii stability theory and linear matrix inequality (LMI) technique, some exponential synchronization criteria are derived.Using the drive-response concept, hybrid feedback controllers are designed to synchronize two identical chaotic neural networks based on those synchronization criteria. Finally, detailed comparisons with existing results are made and numerical simulations are carried out to demonstrate the effectiveness of the established synchronization laws.

  2. Memory delay and haptic feedback influence the dissociation of tactile cues for perception and action.

    Science.gov (United States)

    Davarpanah Jazi, Shirin; Hosang, Stephanie; Heath, Matthew

    2015-05-01

    The somatosensory processing model (SPM) asserts that dissociable cortical processing streams mediate tactile perceptions and actions via relative and absolute cues, respectively (Dijkerman and de Haan, 2007). Accordingly, we sought to determine whether the introduction of a memory delay and/or physically touching a target object (i.e., haptic feedback) differentially influences the cues supporting tactile perceptions and actions. Participants used their right hand to manually estimate (i.e., perceptual task) or grasp (i.e., action task) differently sized objects placed on the palm of their left limb in conditions wherein the target object was available for the duration of the response (i.e., closed-loop condition), or was removed prior to response cuing (i.e., memory-guided condition). As well, trials were performed in conditions wherein the physical object was available (i.e., haptic feedback) or unavailable (i.e., no haptic feedback) to touch. Notably, we computed just-noticeable-difference (JND) scores to determine whether the aforementioned tasks and conditions adhered to - or violated - the relative properties of Weber's law. JNDs for manual estimations adhered to Weber's law across each condition - a finding supporting the SPM's contention that an immutable and relative percept supports tactile perceptions. In turn, JNDs for grasping violated Weber's law only when haptic feedback was available. Such a finding indicates that haptic feedback supports the absolute calibration between a tactile defined object and the required motor output. What is more, our study highlights that multiple somatosensory cues (i.e., tactile and haptic) support goal-directed grasping.

  3. Nonlinear resonance in Duffing oscillator with fixed and integrative time-delayed feedbacks

    Indian Academy of Sciences (India)

    V Ravichandran; V Chinnathambi; S Rajasekar

    2012-03-01

    We study the nonlinear resonance, one of the fundamental phenomena in nonlinear oscillators, in a damped and periodically-driven Duffing oscillator with two types of time-delayed feedbacks, namely, fixed and integrative. Particularly, we analyse the effect of the time-delay parameter and the strength of the time-delayed feedback. Applying the perturbation theory we obtain a nonlinear equation for the amplitude of the periodic response of the system. For a range of values of and , the response amplitude is found to be higher than that of the system in the absence of delayed feedback. The response amplitude is periodic on the parameter with period 2 / where is the angular frequency of the external periodic force. We show the occurrence of multiple branches of the response amplitude curve with and without hysteresis.

  4. Dynamic Behaviors of a Discrete Lotka-Volterra Competition System with Infinite Delays and Single Feedback Control

    Directory of Open Access Journals (Sweden)

    Liang Zhao

    2014-01-01

    Full Text Available A nonautonomous discrete two-species Lotka-Volterra competition system with infinite delays and single feedback control is considered in this paper. By applying the discrete comparison theorem, a set of sufficient conditions which guarantee the permanence of the system is obtained. Also, by constructing some suitable discrete Lyapunov functionals, some sufficient conditions for the global attractivity and extinction of the system are obtained. It is shown that if the the discrete Lotka-Volterra competitive system with infinite delays and without feedback control is permanent, then, by choosing some suitable feedback control variable, the permanent species will be driven to extinction. That is, the feedback control variable, which represents the biological control or some harvesting procedure, is the unstable factor of the system. Such a finding overturns the previous scholars’ recognition on feedback control variables.

  5. Neural basis of the time window for subjective motor-auditory integration

    Directory of Open Access Journals (Sweden)

    Koichi eToida

    2016-01-01

    Full Text Available Temporal contiguity between an action and corresponding auditory feedback is crucial to the perception of self-generated sound. However, the neural mechanisms underlying motor–auditory temporal integration are unclear. Here, we conducted four experiments with an oddball paradigm to examine the specific event-related potentials (ERPs elicited by delayed auditory feedback for a self-generated action. The first experiment confirmed that a pitch-deviant auditory stimulus elicits mismatch negativity (MMN and P300, both when it is generated passively and by the participant’s action. In our second and third experiments, we investigated the ERP components elicited by delayed auditory feedback of for a self-generated action. We found that delayed auditory feedback elicited an enhancement of P2 (enhanced-P2 and a N300 component, which were apparently different from the MMN and P300 components observed in the first experiment. We further investigated the sensitivity of the enhanced-P2 and N300 to delay length in our fourth experiment. Strikingly, the amplitude of the N300 increased as a function of the delay length. Additionally, the N300 amplitude was significantly correlated with the conscious detection of the delay (the 50% detection point was around 200 ms, and hence reduction in the feeling of authorship of the sound (the sense of agency. In contrast, the enhanced-P2 was most prominent in short-delay (≤ 200 ms conditions and diminished in long-delay conditions. Our results suggest that different neural mechanisms are employed for the processing of temporally-deviant and pitch-deviant auditory feedback. Additionally, the temporal window for subjective motor–auditory integration is likely about 200 ms, as indicated by these auditory ERP components.

  6. RESPONSE OF PARAMETRICALLY EXCITED DUFFING-VAN DER POL OSCILLATOR WITH DELAYED FEEDBACK

    Institute of Scientific and Technical Information of China (English)

    LI Xin-ye; CHEN Yu-shu; WU Zhi-qiang; SONG Tao

    2006-01-01

    The dynamical behaviour of a parametrically excited Duffing-van der Pol oscillator under linear-plus-nonlinear state feedback control with a time delay is concerned.By means of the method of averaging together with truncation of Taylor expansions, two slow-flow equations on the amplitude and phase of response were derived for the case of principal parametric resonance. It is shown that the stability condition for the trivial solution is only associated with the linear terms in the original systems besides the amplitude and frequency of parametric excitation. And the trivial solution can be stabilized by appreciate choice of gains and time delay in feedback control. Different from the case of the trivial solution, the stability condition for nontrivial solutions is also associated with nonlinear terms besides linear terms in the original system. It is demonstrated that nontrivial steady state responses may lose their stability by saddle-node (SN) or Hopf bifurcation (HB) as parameters vary. The simulations, obtained by numerically integrating the original system, are in good agreement with the analytical results.

  7. Resonances of a nonlinear SDOF system with time-delay in linear feedback control

    Energy Technology Data Exchange (ETDEWEB)

    El-Bassiouny, A F [Mathematics Department, Faculty of Science, Benha University, Benha 13518 (Egypt); El-kholy, S [Department of Mathematics, Faculty of Science, Menoufia University, Shebin El-kom (Egypt)], E-mail: atef_elbassiouny@yahoo.com

    2010-01-15

    The primary and subharmonic resonances of a nonlinear single-degree-of-freedom (SDOF) system under feedback control with a time delay have been studied by means of an asymptotic perturbation technique. Both external (forcing) and parametric excitations have been included. By means of the averaging method and multiple scales method, two slow-flow equations for the amplitude and phase of the primary and subharmonic resonances and all other parameters are obtained, respectively. The steady state solutions (fixed points) for the original system are investigated. The stability of the fixed points is examined by using the variational method. The effect of the feedback gains, time-delay, the coefficient of cubic term, the coefficients of external and parametric excitations on the steady state responses are investigated and the results are presented as plots of the steady state response amplitude versus the detuning parameter. The results obtained by the two methods are in excellent agreement. There exist saddle node bifurcations for the case of primary resonance and the solutions lose stability for the case of resonance subharmonic.

  8. Bifurcation analysis of a delay reaction-diffusion malware propagation model with feedback control

    Science.gov (United States)

    Zhu, Linhe; Zhao, Hongyong; Wang, Xiaoming

    2015-05-01

    With the rapid development of network information technology, information networks security has become a very critical issue in our work and daily life. This paper attempts to develop a delay reaction-diffusion model with a state feedback controller to describe the process of malware propagation in mobile wireless sensor networks (MWSNs). By analyzing the stability and Hopf bifurcation, we show that the state feedback method can successfully be used to control unstable steady states or periodic oscillations. Moreover, formulas for determining the properties of the bifurcating periodic oscillations are derived by applying the normal form method and center manifold theorem. Finally, we conduct extensive simulations on large-scale MWSNs to evaluate the proposed model. Numerical evidences show that the linear term of the controller is enough to delay the onset of the Hopf bifurcation and the properties of the bifurcation can be regulated to achieve some desirable behaviors by choosing the appropriate higher terms of the controller. Furthermore, we obtain that the spatial-temporal dynamic characteristics of malware propagation are closely related to the rate constant for nodes leaving the infective class for recovered class and the mobile behavior of nodes.

  9. Vibration Analysis of a Piecewise-Smooth System with Negative Stiffness under Delayed Feedback Control

    Directory of Open Access Journals (Sweden)

    Dongmei Huang

    2017-01-01

    Full Text Available The principal resonance of a delayed piecewise-smooth (DPWS system with negative stiffness under narrow-band random excitation is investigated in aspects of multiscale analysis, design methodology of the controller, and response properties. The amplitude-frequency response and steady-state moments together with the corresponding stability conditions of the controlled stochastic system are derived, in which the degradation case is also under consideration. Then, from the perspective of the equivalent damping, the comparisons of the response characteristics of the controlled system to the uncontrolled system, such as the phenomenon of frequency island, are fulfilled. Furthermore, sensitivity of the system response to feedback gain and time delay is studied and interesting dynamic properties are found. Meanwhile, the classification of the steady-state solution is also discussed. To control the maximum amplitude, the feedback parameters are determined by the frequency response together with stability boundaries which must be utilized to exclude the combinations of the unstable parameters. For the case with small noise intensity, mean-square responses present the similar characteristics to what is discussed in the deterministic case.

  10. Stochastic thermodynamics of Langevin systems under time-delayed feedback control: Second-law-like inequalities.

    Science.gov (United States)

    Rosinberg, M L; Munakata, T; Tarjus, G

    2015-04-01

    Response lags are generic to almost any physical system and often play a crucial role in the feedback loops present in artificial nanodevices and biological molecular machines. In this paper, we perform a comprehensive study of small stochastic systems governed by an underdamped Langevin equation and driven out of equilibrium by a time-delayed continuous feedback control. In their normal operating regime, these systems settle in a nonequilibrium steady state in which work is permanently extracted from the surrounding heat bath. By using the Fokker-Planck representation of the dynamics, we derive a set of second-law-like inequalities that provide bounds to the rate of extracted work. These inequalities involve additional contributions characterizing the reduction of entropy production due to the continuous measurement process. We also show that the non-Markovian nature of the dynamics requires a modification of the basic relation linking dissipation to the breaking of time-reversal symmetry at the level of trajectories. The modified relation includes a contribution arising from the acausal character of the reverse process. This, in turn, leads to another second-law-like inequality. We illustrate the general formalism with a detailed analytical and numerical study of a harmonic oscillator driven by a linear feedback, which describes actual experimental setups.

  11. Long-range correlation properties in timing of skilled piano performance: the influence of auditory feedback and deep brain stimulation.

    Science.gov (United States)

    Herrojo Ruiz, María; Hong, Sang Bin; Hennig, Holger; Altenmüller, Eckart; Kühn, Andrea A

    2014-01-01

    Unintentional timing deviations during musical performance can be conceived of as timing errors. However, recent research on humanizing computer-generated music has demonstrated that timing fluctuations that exhibit long-range temporal correlations (LRTC) are preferred by human listeners. This preference can be accounted for by the ubiquitous presence of LRTC in human tapping and rhythmic performances. Interestingly, the manifestation of LRTC in tapping behavior seems to be driven in a subject-specific manner by the LRTC properties of resting-state background cortical oscillatory activity. In this framework, the current study aimed to investigate whether propagation of timing deviations during the skilled, memorized piano performance (without metronome) of 17 professional pianists exhibits LRTC and whether the structure of the correlations is influenced by the presence or absence of auditory feedback. As an additional goal, we set out to investigate the influence of altering the dynamics along the cortico-basal-ganglia-thalamo-cortical network via deep brain stimulation (DBS) on the LRTC properties of musical performance. Specifically, we investigated temporal deviations during the skilled piano performance of a non-professional pianist who was treated with subthalamic-deep brain stimulation (STN-DBS) due to severe Parkinson's disease, with predominant tremor affecting his right upper extremity. In the tremor-affected right hand, the timing fluctuations of the performance exhibited random correlations with DBS OFF. By contrast, DBS restored long-range dependency in the temporal fluctuations, corresponding with the general motor improvement on DBS. Overall, the present investigations demonstrate the presence of LRTC in skilled piano performances, indicating that unintentional temporal deviations are correlated over a wide range of time scales. This phenomenon is stable after removal of the auditory feedback, but is altered by STN-DBS, which suggests that cortico

  12. Long-range correlation properties in timing of skilled piano performance: the influence of auditory feedback and deep brain stimulation.

    Directory of Open Access Journals (Sweden)

    Maria eHerrojo Ruiz

    2014-09-01

    Full Text Available Unintentional timing deviations during musical performance can be conceived of as timing errors. However, recent research on humanizing computer-generated music has demonstrated that timing fluctuations that exhibit long-range temporal correlations (LRTC are preferred by human listeners. This preference can be accounted for by the ubiquitous presence of LRTC in human tapping and rhythmic performances. Interestingly, the manifestation of LRTC in tapping behavior seems to be driven in a subject-specific manner by the LRTC properties of resting-state background cortical oscillatory activity. In this framework, the current study aimed to investigate whether propagation of timing deviations during the skilled, memorized piano performance (without metronome of 17 professional pianists exhibits LRTC and whether the structure of the correlations is influenced by the presence or absence of auditory feedback.As an additional goal, we set out to investigate the influence of altering the dynamics along the cortico-basal-ganglia-thalamo-cortical network via deep brain stimulation (DBS on the LRTC properties of musical performance. Specifically, we investigated temporal deviations during the skilled piano performance of a non-professional pianist who was treated with subthalamic-deep brain stimulation (STN-DBS due to severe Parkinson's disease, with predominant tremor affecting his right upper extremity. In the tremor-affected right hand, the timing fluctuations of the performance exhibited random correlations with DBS OFF. By contrast, DBS restored long-range dependency in the temporal fluctuations, corresponding with the general motor improvement on DBS.Overall, the present investigations are the first to demonstrate the presence of LRTC in skilled piano performances, indicating that unintentional temporal deviations are correlated over a wide range of time scales. This phenomenon is stable after removal of the auditory feedback, but is altered by STN

  13. Response of the Duffing-Van der Pol Oscillator under Position Feedback Control with Two Time Delays

    Directory of Open Access Journals (Sweden)

    Xinye Li

    2011-01-01

    Full Text Available In this paper, the dynamics of Duffing-van der Pol oscillators under linear-plus-nonlinear position feedback control with two time delays is studied analytically and numerically. By the averaging method, together with truncation of Taylor expansions for those terms with time delay, the slow-flow equations are obtained from which the trivial and nontrivial solutions can be found. It is shown that the trivial solution can be stabilized by appropriate gain and time delay in linear feedback although it loses its stability via Hopf bifurcation and results in periodic solution for uncontrolled systems. And the stability of the trivial solution is independent of nonlinear feedback. Different from the case of the trivial solution, the stability of nontrivial solutions is also associated with nonlinear feedback besides linear feedback. Non-trivial solutions may lose their stability via saddle-node or Hopf bifurcation and the resulting response of the system may be quasi-periodic or chaotic. The feedback gains and time delays have great effects on the amplitude of the periodic solutions and their bifurcation control. The simulations, obtained by numerically integrating the original system, are in good agreement with the analytical results.

  14. Studies on effects of feedback delay on the convergence performance of adaptive time-domain equalizers for fiber dispersive channels

    Science.gov (United States)

    Guo, Qun; Xu, Bo; Qiu, Kun

    2016-04-01

    Adaptive time-domain equalizer (TDE) is an important module for digital optical coherent receivers. From an implementation perspective, we analyze and compare in detail the effects of error signal feedback delay on the convergence performance of TDE using either least-mean square (LMS) or constant modulus algorithm (CMA). For this purpose, a simplified theoretical model is proposed based on which iterative equations on the mean value and the variance of the tap coefficient are derived with or without error signal feedback delay for both LMS- and CMA-based methods for the first time. The analytical results show that decreased step size has to be used for TDE to converge and a slower convergence speed cannot be avoided as the feedback delay increases. Compared with the data-aided LMS-based method, the CMA-based method has a slower convergence speed and larger variation after convergence. Similar results are confirmed using numerical simulations for fiber dispersive channels. As the step size increases, a feedback delay of 20 clock cycles might cause the TDE to diverge. Compared with the CMA-based method, the LMS-based method has a higher tolerance on the feedback delay and allows a larger step size for a faster convergence speed.

  15. Comparison of cochlear delay estimates using otoacoustic emissions and auditory brainstem responses

    DEFF Research Database (Denmark)

    Harte, James; Pigasse, Gilles; Dau, Torsten

    2009-01-01

    delay non-invasively in normal-hearing humans. Tone bursts at nine frequencies from 0.5 to 8 kHz served as stimuli, with care taken to quantify possible bias due to the use of tone bursts with different rise times. BM delays are estimated from the ABR latency estimates by subtracting the neural...... and synaptic delays. This allows a comparison between individual OAE and BM delays over a large frequency range in the same subjects, and offers support to the theory that OAEs are reflected from a tonotopic place and carried back to the cochlear base via a reverse traveling wave....

  16. Analysis of a dc bus system with a nonlinear constant power load and its delayed feedback control.

    Science.gov (United States)

    Konishi, Keiji; Sugitani, Yoshiki; Hara, Naoyuki

    2014-02-01

    This paper tackles a destabilizing problem of a direct-current (dc) bus system with constant power loads, which can be considered a fundamental problem of dc power grid networks. The present paper clarifies scenarios of the destabilization and applies the well-known delayed-feedback control to the stabilization of the destabilized bus system on the basis of nonlinear science. Further, we propose a systematic procedure for designing the delayed feedback controller. This controller can converge the bus voltage exactly on an unstable operating point without accurate information and can track it using tiny control energy even when a system parameter, such as the power consumption of the load, is slowly varied. These features demonstrate that delayed feedback control can be considered a strong candidate for solving the destabilizing problem.

  17. Guaranteed Cost Control for Exponential Synchronization of Cellular Neural Networks with Mixed Time-Varying Delays via Hybrid Feedback Control

    Directory of Open Access Journals (Sweden)

    T. Botmart

    2013-01-01

    Full Text Available The problem of guaranteed cost control for exponential synchronization of cellular neural networks with interval nondifferentiable and distributed time-varying delays via hybrid feedback control is considered. The interval time-varying delay function is not necessary to be differentiable. Based on the construction of improved Lyapunov-Krasovskii functionals is combined with Leibniz-Newton's formula and the technique of dealing with some integral terms. New delay-dependent sufficient conditions for the exponential synchronization of the error systems with memoryless hybrid feedback control are first established in terms of LMIs without introducing any free-weighting matrices. The optimal guaranteed cost control with linear error hybrid feedback is turned into the solvable problem of a set of LMIs. A numerical example is also given to illustrate the effectiveness of the proposed method.

  18. On asymptotic stabilisation of a chain of integrators with nonlinearity and an uncertain input delay by output feedback

    Science.gov (United States)

    Choi, Ho-Lim

    2014-12-01

    In this paper, we provide an output feedback solution over one given by Choi and Lim [Systems & Control Letters, 59(6), 374-379 (2010)] under more generalised system set-up. More specifically, we consider a stabilisation problem of a chain of integrators that has nonlinearity and an uncertain delay in the input by output feedback. The nonlinearity is classified into four types. Then, we propose a memoryless output feedback controller which contains a gain-scaling factor to adjust controller gains depending on the given nonlinearity type. Our stability analysis shows that the controlled system has unique stabilisation result associated with each type of nonlinearity. Our result provides a new aspect to the stabilisation problem of nonlinear time-delay systems and broadens the existing control results of time-delay systems. Two examples are given for illustration.

  19. Performance characteristics of positive and negative delayed feedback on chaotic dynamics of directly modulated InGaAsP semiconductor lasers

    Indian Academy of Sciences (India)

    Bindu M Krishna; Manu P John; V M Nandakumaran

    2008-12-01

    The chaotic dynamics of directly modulated semiconductor lasers with delayed optoelectronic feedback is studied numerically. The effects of positive and negative delayed optoelectronic feedback in producing chaotic outputs from such lasers with nonlinear gain reduction in its optimum value range is investigated using bifurcation diagrams. The results are confirmed by calculating the Lyapunov exponents. A negative delayed optoelectronic feedback configuration is found to be more effective in inducing chaotic dynamics to such systems with nonlinear gain reduction factor in the practical value range.

  20. The effect of visual feedback and training in auditory-perceptual judgment of voice quality

    NARCIS (Netherlands)

    Barsties, Ben; Beers, Mieke; Ten Cate, Liesbeth; Van Ballegooijen, Karin; Braam, Lilian; De Groot, Merel; Van Der Kant, Marieke; Kruitwagen, Cas|info:eu-repo/dai/nl/304826790; Maryn, Youri

    2017-01-01

    The aim of the present investigation was to evaluate the effect of visual feedback on rating voice quality severity level and the reliability of voice quality judgment by inexperienced listeners. For this purpose two training programs were created, each lasting 2 hours. In total 37 undergraduate spe

  1. Ultra-high-frequency piecewise-linear chaos using delayed feedback loops

    Science.gov (United States)

    Cohen, Seth D.; Rontani, Damien; Gauthier, Daniel J.

    2012-12-01

    We report on an ultra-high-frequency (>1 GHz), piecewise-linear chaotic system designed from low-cost, commercially available electronic components. The system is composed of two electronic time-delayed feedback loops: A primary analog loop with a variable gain that produces multi-mode oscillations centered around 2 GHz and a secondary loop that switches the variable gain between two different values by means of a digital-like signal. We demonstrate experimentally and numerically that such an approach allows for the simultaneous generation of analog and digital chaos, where the digital chaos can be used to partition the system's attractor, forming the foundation for a symbolic dynamics with potential applications in noise-resilient communications and radar.

  2. Noise-induced standing waves in oscillatory systems with time-delayed feedback

    CERN Document Server

    Stich, Michael

    2016-01-01

    In oscillatory reaction-diffusion systems, time-delay feedback can lead to the instability of uniform oscillations with respect to formation of standing waves. Here, we investigate how the presence of additive, Gaussian white noise can induce the appearance of standing waves. Combining analytical solutions of the model with spatio-temporal simulations, we find that noise can promote standing waves in regimes where the deterministic uniform oscillatory modes are stabilized. As the deterministic phase boundary is approached, the spatio-temporal correlations become stronger, such that even small noise can induce standing waves in this parameter regime. With larger noise strengths, standing waves could be induced at finite distances from the (deterministic) phase boundary. The overall dynamics is defined through the interplay of noisy forcing with the inherent reaction-diffusion dynamics.

  3. Chaotic millimeter wave generation in a helical-waveguide gyro-TWT with delayed feedback

    Science.gov (United States)

    Ginzburg, N. S.; Rozental, R. M.; Sergeev, A. S.; Zotova, I. V.; Tarakanov, V. P.

    2016-10-01

    We demonstrate the possibility of chaotic millimeter wave generation in broadband helical-waveguide gyrotron travelling wave tubes (gyro-TWTs) by introducing external delayed feedback. It is shown that for the realization of "developed" chaos the amplitude characteristic of the amplifier should have the maximum slope in the overdrive regime upon saturation. This can be achieved by proper choosing of cyclotron resonance detuning. According to the time-domain averaged model and 3D particle-in-cell simulations with the parameters of the experimentally realized 35 GHz gyro-TWT, the power of chaotic generation can achieve 50 kW for an electron mean efficiency of about 7% and a spectrum width of 3-4 GHz.

  4. Adaptive feedback synchronisation of complex dynamical network with discrete-time communications and delayed nodes

    Science.gov (United States)

    Wang, Tong; Ding, Yongsheng; Zhang, Lei; Hao, Kuangrong

    2016-08-01

    This paper considered the synchronisation of continuous complex dynamical networks with discrete-time communications and delayed nodes. The nodes in the dynamical networks act in the continuous manner, while the communications between nodes are discrete-time; that is, they communicate with others only at discrete time instants. The communication intervals in communication period can be uncertain and variable. By using a piecewise Lyapunov-Krasovskii function to govern the characteristics of the discrete communication instants, we investigate the adaptive feedback synchronisation and a criterion is derived to guarantee the existence of the desired controllers. The globally exponential synchronisation can be achieved by the controllers under the updating laws. Finally, two numerical examples including globally coupled network and nearest-neighbour coupled networks are presented to demonstrate the validity and effectiveness of the proposed control scheme.

  5. Power grid enhanced resilience using proportional and derivative control with delayed feedback

    Science.gov (United States)

    Dongmo, Eric Donald; Colet, Pere; Woafo, Paul

    2017-01-01

    This paper investigates the resilience of an elementary electricity system (machine-generator) under proportional and derivative (PD) control when subject to large perturbations. A particular attention is paid to small power grids, representative of power grid structure in some developing countries. The considered elementary electricity system consists of a consumer (machine), a power plant (generator) and a transmission line. Both Runge-Kutta and Newton methods are used to solve the dynamical equations and the characteristic equations for stability. It is found that the controller increases the resilience of the system. We also show that time delays associated to the feedback loop of the controller have a negative impact on the performance. It is also shown that the asymmetry due to energy demand of different consumers to power plant increases the stability of the system.

  6. Coupled map car-following model and its delayed-feedback control.

    Science.gov (United States)

    Konishi, K; Kokame, H; Hirata, K

    1999-10-01

    This paper proposes a coupled map car-following traffic model, which describes a dynamical behavior of a group of road vehicles running in a single lane without overtaking. This model consists of a lead vehicle and following vehicles, which have a piecewise linear optimal velocity function. When the lead-vehicle speed is varied, we can observe a traffic jam in the group of the vehicles. We derive a condition under which the traffic jam never occurs in our model. Furthermore, in order to suppress the traffic jam, for each vehicle we use a dynamic version of decentralized delayed-feedback control proposed in [Konishi, Hirai, and Kokame, Phys. Rev. E 58, 3055 (1998)], and provide a systematic procedure for designing the controller.

  7. Delay-feedback control strategy for reducing CO2 emission of traffic flow system

    Science.gov (United States)

    Zhang, Li-Dong; Zhu, Wen-Xing

    2015-06-01

    To study the signal control strategy for reducing traffic emission theoretically, we first presented a kind of discrete traffic flow model with relative speed term based on traditional coupled map car-following model. In the model, the relative speed difference between two successive running cars is incorporated into following vehicle's acceleration running equation. Then we analyzed its stability condition with discrete control system stability theory. Third, we designed a delay-feedback controller to suppress traffic jam and decrease traffic emission based on modern controller theory. Last, numerical simulations are made to support our theoretical results, including the comparison of models' stability analysis, the influence of model type and signal control on CO2 emissions. The results show that the temporal behavior of our model is superior to other models, and the traffic signal controller has good effect on traffic jam suppression and traffic CO2 emission, which fully supports the theoretical conclusions.

  8. Synchronous and stochastic oscillations in a nonautonomous transistor oscillator with delayed feedback

    Science.gov (United States)

    Kal'Ianov, E. V.

    1986-11-01

    The stimulation by an external signal of stochastic self-excited oscillations in a nonautonomous transistor oscillator with delayed feedback is investigated experimentally, with a focus on the case of parametric pumping, where the frequency of the external signal is close to the interval between the natural frequencies of the system. The experimental technique and apparatus are similar to those employed by Kal'ianov and Starkov (1985), and the results are presented graphically. Phenomena observed include both (1) enrichment of the oscillation spectrum by excitation of additional, asynchronously interacting modes until a transition to chaos occurs; and (2) parametric suppression of oscillations at certain modes, with phase locking of the mode oscillations and the establishment of synchronous oscillations (i.e., destochastization).

  9. Firing statistics of inhibitory neuron with delayed feedback. II: Non-Markovian behavior.

    Science.gov (United States)

    Kravchuk, K G; Vidybida, A K

    2013-06-01

    The instantaneous state of a neural network consists of both the degree of excitation of each neuron the network is composed of and positions of impulses in communication lines between the neurons. In neurophysiological experiments, the neuronal firing moments are registered, but not the state of communication lines. But future spiking moments depend essentially on the past positions of impulses in the lines. This suggests, that the sequence of intervals between firing moments (inter-spike intervals, ISIs) in the network could be non-Markovian. In this paper, we address this question for a simplest possible neural "net", namely, a single inhibitory neuron with delayed feedback. The neuron receives excitatory input from the driving Poisson stream and inhibitory impulses from its own output through the feedback line. We obtain analytic expressions for conditional probability density P(tn+1|tn, …, t1, t0), which gives the probability to get an output ISI of duration tn+1 provided the previous (n+1) output ISIs had durations tn, …, t1, t0. It is proven exactly, that P(tn+1|tn, …, t1, t0) does not reduce to P(tn+1|tn, …, t1) for any n≥0. This means that the output ISIs stream cannot be represented as a Markov chain of any finite order.

  10. Fast photonic information processing using semiconductor lasers with delayed optical feedback: role of phase dynamics.

    Science.gov (United States)

    Nguimdo, Romain Modeste; Verschaffelt, Guy; Danckaert, Jan; Van der Sande, Guy

    2014-04-01

    Semiconductor lasers subject to delayed optical feedback have recently shown great potential in solving computationally hard tasks. By optically implementing a neuro-inspired computational scheme, called reservoir computing, based on the transient response to optical data injection, high processing speeds have been demonstrated. While previous efforts have focused on signal bandwidths limited by the semiconductor laser's relaxation oscillation frequency, we demonstrate numerically that the much faster phase response makes significantly higher processing speeds attainable. Moreover, this also leads to shorter external cavity lengths facilitating future on-chip implementations. We numerically benchmark our system on a chaotic time-series prediction task considering two different feedback configurations. The results show that a prediction error below 4% can be obtained when the data is processed at 0.25 GSamples/s. In addition, our insight into the phase dynamics of optical injection in a semiconductor laser also provides a clear understanding of the system performance at different pump current levels, even below solitary laser threshold. Considering spontaneous emission noise and noise in the readout layer, we obtain good prediction performance at fast processing speeds for realistic values of the noise strength.

  11. Broadcast Channels with Delayed Finite-Rate Feedback: Predict or Observe?

    CERN Document Server

    Xu, Jiaming; Jafar, Syed A

    2011-01-01

    Most multiuser precoding techniques require accurate transmitter channel state information (CSIT) to maintain orthogonality between the users. Such techniques have proven quite fragile in time-varying channels because the CSIT is inherently imperfect due to estimation and feedback delay, as well quantization noise. An alternative approach recently proposed by Maddah-Ali and Tse (MAT) allows for significant multiplexing gain in the multi-input single-output (MISO) broadcast channel (BC) even with transmit CSIT that is completely stale, i.e. uncorrelated with the current channel state. With $K$ users, their scheme claims to lose only a $\\log(K)$ factor relative to the full $K$ degrees of freedom (DoF) attainable in the MISO BC with perfect CSIT for large $K$. However, their result does not consider the cost of the feedback, which is potentially very large in high mobility (short channel coherence time). In this paper, we more closely examine the MAT scheme and compare its DoF gain to single user transmission (w...

  12. Delayed Feedback Control of 2D Roll-Cell by Pulsed Jets

    Science.gov (United States)

    Ogawara, Kakuji

    1998-11-01

    Experimental study and numerical experiments were conducted to examine applicability of Pyragas' delayed feedback(DFB) control theory for active control of fluid flow. Although many attempts of turbulence active control have been made, most of those experimental studies experience "out of control" state in the case of using larger feedback gain. In the present study, we assume this "out of control" state as Chaos, and apply chaos control theory to prevent the flow field from falling into "out of control" state. Experiments were carried out for low Reynolds number oil flow in a rectangle thin container, whose aspect ratio is 6:1:0.5. Two pulsed jets were used as actuator in order to keep the circulation of the flow in container constant. Fluid flow was observed using Particle Image Velocimetry (PIV) technology and the flow state was estimated by moving least square (MLS) method. As a result, we found that Pyragas control was effective to prevent chaos for active control fo fluid flow. Numerical simulations were also carried out by using the coupled map lattice(CML). CML is known as a simple model with the essential feature of spatio-temporal chaos. DFB control was applied for CML to examine possibility of active control of turbulence. Simulating results show that the present method can stabilize the whole system of CML.

  13. Self-Generated Auditory Feedback as a Cue to Support Rhythmic Motor Stability

    Directory of Open Access Journals (Sweden)

    Gopher Daniel

    2011-12-01

    Full Text Available A goal of the SKILLS project is to develop Virtual Reality (VR-based training simulators for different application domains, one of which is juggling. Within this context the value of multimodal VR environments for skill acquisition is investigated. In this study, we investigated whether it was necessary to render the sounds of virtual balls hitting virtual hands within the juggling training simulator. First, we recorded sounds at the jugglers’ ears and found the sound of ball hitting hands to be audible. Second, we asked 24 jugglers to juggle under normal conditions (Audible or while listening to pink noise intended to mask the juggling sounds (Inaudible. We found that although the jugglers themselves reported no difference in their juggling across these two conditions, external juggling experts rated rhythmic stability worse in the Inaudible condition than in the Audible condition. This result suggests that auditory information should be rendered in the VR juggling training simulator.

  14. Time-delay signatures in multi-transverse mode VCSELs subject to double-cavity polarization-rotated optical feedback

    Science.gov (United States)

    Lin, Hong; Khurram, Aliza; Hong, Yanhua

    2016-10-01

    Time delay (TD) signatures are studied experimentally in orthogonal polarizations and in individual transverse modes respectively in a VCSEL operating with three transverse modes. Different types of concealment of the TD signatures are observed when the polarization of feedback is rotated through large angles. Effects of feedback strength and external cavity length on the TD signatures are investigated. Weak feedback leads to better concealment of the TD signatures in the dominant polarization. When the round-trip time difference between the two external cavities is close to a half of the relaxation oscillation period, the TD signatures are minimized.

  15. Speakers' acceptance of real-time speech exchange indicates that we use auditory feedback to specify the meaning of what we say.

    Science.gov (United States)

    Lind, Andreas; Hall, Lars; Breidegard, Björn; Balkenius, Christian; Johansson, Petter

    2014-06-01

    Speech is usually assumed to start with a clearly defined preverbal message, which provides a benchmark for self-monitoring and a robust sense of agency for one's utterances. However, an alternative hypothesis states that speakers often have no detailed preview of what they are about to say, and that they instead use auditory feedback to infer the meaning of their words. In the experiment reported here, participants performed a Stroop color-naming task while we covertly manipulated their auditory feedback in real time so that they said one thing but heard themselves saying something else. Under ideal timing conditions, two thirds of these semantic exchanges went undetected by the participants, and in 85% of all nondetected exchanges, the inserted words were experienced as self-produced. These findings indicate that the sense of agency for speech has a strong inferential component, and that auditory feedback of one's own voice acts as a pathway for semantic monitoring, potentially overriding other feedback loops. © The Author(s) 2014.

  16. Effect of feedback on delaying deterioration in quality of compressions during 2 minutes of continuous chest compressions

    DEFF Research Database (Denmark)

    Lyngeraa, Tobias S; Hjortrup, Peter Buhl; Wulff, Nille B

    2012-01-01

    delays deterioration of quality of compressions. METHODS: Participants attending a national one-day conference on cardiac arrest and CPR in Denmark were randomized to perform single-rescuer BLS with (n = 26) or without verbal and visual feedback (n = 28) on a manikin using a ZOLL AED plus. Data were...... was the proportion of delivered compressions within target rate compared over a 2-minute period within the groups and between the groups. Performance variables for 30-second intervals were analyzed and compared. RESULTS: 24 (92%) and 23 (82%) had CPR experience in the group with and without feedback respectively. 14...... (54%) were CPR instructors in the feedback group and 18 (64%) in the group without feedback. Data from 26 and 28 participants were analyzed respectively. Although median values for proportion of delivered compressions within target depth were higher in the feedback group (0-30s: 54.0%; 30-60s: 88...

  17. On utilizing delayed feedback for active-multimode vibration control of cantilever beams

    Science.gov (United States)

    Alhazza, Khaled A.; Nayfeh, Ali H.; Daqaq, Mohammed F.

    2009-01-01

    We present a single-input single-output multimode delayed-feedback control methodology to mitigate the free vibrations of a flexible cantilever beam. For the purpose of controller design and stability analysis, we consider a reduced-order model consisting of the first n vibration modes. The temporal variation of these modes is represented by a set of nonlinearly coupled ordinary-differential equations that capture the evolving dynamics of the beam. Considering a linearized version of these equations, we derive a set of analytical conditions that are solved numerically to assess the stability of the closed-loop system. To verify these conditions, we characterize the stability boundaries using the first two vibration modes and compare them to damping contours obtained by long-time integration of the full nonlinear equations of motion. Simulations show excellent agreement between both approaches. We analyze the effect of the size and location of the piezoelectric patch and the location of the sensor on the stability of the response. We show that the stability boundaries are highly dependent on these parameters. Finally, we implement the controller on a cantilever beam for different controller gain-delay combinations and assess the performance using time histories of the beam response. Numerical simulations clearly demonstrate the controller ability to mitigate vibrations emanating from multiple modes simultaneously.

  18. Axonal branching patterns as sources of delay in the mammalian auditory brainstem: a re-examination.

    Science.gov (United States)

    Karino, Shotaro; Smith, Philip H; Yin, Tom C T; Joris, Philip X

    2011-02-23

    In models of temporal processing, time delays incurred by axonal propagation of action potentials play a prominent role. A pre-eminent model of temporal processing in audition is the binaural model of Jeffress (1948), which has dominated theories regarding our acute sensitivity to interaural time differences (ITDs). In Jeffress' model, a binaural cell is maximally active when the ITD is compensated by an internal delay, which brings the inputs from left and right ears in coincidence, and which would arise from axonal branching patterns of monaural input fibers. By arranging these patterns in systematic and opposite ways for the ipsilateral and contralateral inputs, a range of length differences, and thereby of internal delays, is created so that the ITD is transformed into a spatial activation pattern along the binaural nucleus. We reanalyze single, labeled, and physiologically characterized axons of spherical bushy cells of the cat anteroventral cochlear nucleus, which project to binaural coincidence detectors in the medial superior olive (MSO). The reconstructions largely confirm the observations of two previous reports, but several features are observed that are inconsistent with Jeffress' model. We found that ipsilateral projections can also form a caudally directed delay line pattern, which would counteract delays incurred by caudally directed contralateral projections. Comparisons of estimated axonal delays with binaural physiological data indicate that the suggestive anatomical patterns cannot account for the frequency-dependent distribution of best delays in the cat. Surprisingly, the tonotopic distribution of the afferent endings indicate that low characteristic frequencies are under-represented rather than over-represented in the MSO.

  19. Stability and Feedback Design of a Class of Time-Delay Systems with Discontinuity: Functional Differential Inclusion-Based Approach

    Science.gov (United States)

    Zhang, Jiangyan; Shen, Tielong

    To analyze and synthesize time-delay systems with discontinuity, the framework of differential inclusion in the sense of Filippov is extended to functional differential inclusion. Based on the extension, the concept of Filippov solution is introduced for the time-delay systems with discontinuity at first, and then it is shown that both the Lyapunov stability and the LaSalle invariance principle results can be extended to such kind of systems. Moreover, by using the proposed analysis tools, a stabilization feedback design approach is proposed for a class of nonlinear time-delay systems with discontinuity. Simulation results of numerical examples are given to demonstrate the proposed control approaches.

  20. The Effect of Online Gaming, Cognition and Feedback Type in Facilitating Delayed Achievement of Different Learning Objectives

    Science.gov (United States)

    Cameron, Brian; Dwyer, Francis

    2005-01-01

    Online and computer-based instructional gaming is becoming a viable instructional strategy at all levels of education. The purpose of this study was to examine the effect of (a) gaming, (b) gaming plus embedded questions, and (c) gaming plus questions plus feedback on delayed retention of different types of educational objectives for students…

  1. Attractivity in a Delayed Three-species Ratio-dependent Predator-prey System without Dominating Instantaneous Negative Feedback

    Institute of Scientific and Technical Information of China (English)

    Rui Xu; Lan-sun Chen; M.A.J. Chaplain

    2003-01-01

    A delayed three-species ratio-dependent predator-prey food-chain model without dominating instantaneous negative feedback is investigated. It is shown that the system is permanent under some appropriate conditions, and sufficient conditions are derived for the global attractivity of the positive equilibrium of the system.

  2. Stabilization of a semilinear wave equation with variable coefficients and a delay term in the boundary feedback

    Directory of Open Access Journals (Sweden)

    Jing Li

    2013-04-01

    Full Text Available We study the uniform stabilization of a semilinear wave equation with variable coefficients and a delay term in the boundary feedback. The Riemannian geometry method is applied to prove the exponential stability of the system by introducing an equivalent energy function.

  3. Note on the Persistent Property of a Discrete Lotka-Volterra Competitive System with Delays and Feedback Controls

    Directory of Open Access Journals (Sweden)

    Kong Xiangzeng

    2010-01-01

    Full Text Available A nonautonomous -species discrete Lotka-Volterra competitive system with delays and feedback controls is considered in this work. Sufficient conditions on the coefficients are given to guarantee that all the species are permanent. It is shown that these conditions are weaker than those of Liao et al. 2008.

  4. Time-Delay Signature of Chaotic Vertical-Cavity Surface-Emitting Lasers with Polarization-Rotated Optical Feedback

    Institute of Scientific and Technical Information of China (English)

    XIANG Shui-Ying; PAN Wei; YAN Lian-Shan; LUO Bin; ZOU Xi-Hua; JIANG Ning; WEN Kun-Hua

    2011-01-01

    To quantitatively evaluate the time-delay (TD) signatures of chaotic signals generated by vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated optical feedback (PROF), we propose four cases of resolution coefficients R based on correlation functions. The resolution coefficient characteristics for the x-polarization (XP) mode, y-polarization (YP) mode and the total output are considered. The dependences of R on the feedback strength and feedback delay are discussed and compared carefully. The two-dimensional maps of R show that the TD signatures for the single polarization mode (I.e., XP or YP mode) are much more difficult to retrieve than those for the total output in the entire parameter space. Thus, by using single polarization mode as a chaotic carrier, the TD signatures are extremely difficult to be identified, which contributes a lot in the security-enhanced VCSELs-based chaotic optical communication systems.

  5. Decentralised adaptive output feedback stabilisation for stochastic time-delay systems via LaSalle-Yoshizawa-type theorem

    Science.gov (United States)

    Jiao, Ticao; Xu, Shengyuan; Lu, Junwei; Wei, Yunliang; Zou, Yun

    2016-01-01

    This paper deals with the decentralised output feedback stabilisation problem for a class of large-scale stochastic time-delay nonlinear systems. A general theorem is firstly given to guarantee the global existence and uniqueness of the solution for stochastic time-delay systems. In addition, a stochastic version of the well-known LaSalle-Yoshizawa theorem with time-varying delay is initially proposed for the controller design and stability analysis. Then, for a class of large-scale stochastic systems with time-varying delays, totally decentralised adaptive delay-dependent controllers are designed by using K-filter and backstepping approach. Via LaSalle-Yoshizawa-type theorem and constructing a general Lyapunov function, it is shown that all signals in the closed-loop system are bounded almost surely and the solution is almost surely asymptotically stable. Finally, a simulation example is given to illustrate the effectiveness of the results of this paper.

  6. General Purpose Digital Signal Processing VME-Module for 1-Turn Delay Feedback Systems of the CERN Accelerator Chain

    CERN Document Server

    Rossi, V

    2010-01-01

    In the framework of the LHC project and the modifications of the SPS as its injector, the concept has been developed of a global digital signal processing unit (DSPU) that implements in numerical form the architecture of low-level RF systems. Since 2002 a Digital Notch Filter with programmable delay for the SPS Transverse Damper has been fully operational with fixed target and LHC-type beams circulating in the SPS. The approach, using an FPGA as core for the low-level system, is very flexible and allows the upgrade of the signal processing by modification of the original firmware. The development for the LHC 1-Turn delay Feedback has benefited from the same methodology and similar technology. The achieved performances of the LHC 1-Turn delay Feedback are compared with project requirements. The project flow for the recent LHC 1-T Feedback allows synergy with several other applications. The CERN PS Transverse Damper DSPU, with automatic delay compensation adapting the loop delay to the time of flight of the par...

  7. Exponential synchronization of discontinuous neural networks with time-varying mixed delays via state feedback and impulsive control.

    Science.gov (United States)

    Yang, Xinsong; Cao, Jinde; Ho, Daniel W C

    2015-04-01

    This paper investigates drive-response synchronization for a class of neural networks with time-varying discrete and distributed delays (mixed delays) as well as discontinuous activations. Strict mathematical proof shows the global existence of Filippov solutions to neural networks with discontinuous activation functions and the mixed delays. State feedback controller and impulsive controller are designed respectively to guarantee global exponential synchronization of the neural networks. By using Lyapunov function and new analysis techniques, several new synchronization criteria are obtained. Moreover, lower bound on the convergence rate is explicitly estimated when state feedback controller is utilized. Results of this paper are new and some existing ones are extended and improved. Finally, numerical simulations are given to verify the effectiveness of the theoretical results.

  8. Auditory short-term memory activation during score reading.

    Directory of Open Access Journals (Sweden)

    Veerle L Simoens

    Full Text Available Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during such a complicated procedure. There were three parts in this study. First, professional musicians participated in an electroencephalographic (EEG experiment to study the slow wave potentials during a time interval of short-term memory storage in a situation that requires cross-modal translation and short-term storage of visual material to be compared with delayed auditory material, as it is the case in music score reading. This delayed visual-to-auditory matching task was compared with delayed visual-visual and auditory-auditory matching tasks in terms of EEG topography and voltage amplitudes. Second, an additional behavioural experiment was performed to determine which type of distractor would be the most interfering with the score reading-like task. Third, the self-reported strategies of the participants were also analyzed. All three parts of this study point towards the same conclusion according to which during music score reading, the musician most likely first translates the visual score into an auditory cue, probably starting around 700 or 1300 ms, ready for storage and delayed comparison with the auditory feedback.

  9. Auditory short-term memory activation during score reading.

    Science.gov (United States)

    Simoens, Veerle L; Tervaniemi, Mari

    2013-01-01

    Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during such a complicated procedure. There were three parts in this study. First, professional musicians participated in an electroencephalographic (EEG) experiment to study the slow wave potentials during a time interval of short-term memory storage in a situation that requires cross-modal translation and short-term storage of visual material to be compared with delayed auditory material, as it is the case in music score reading. This delayed visual-to-auditory matching task was compared with delayed visual-visual and auditory-auditory matching tasks in terms of EEG topography and voltage amplitudes. Second, an additional behavioural experiment was performed to determine which type of distractor would be the most interfering with the score reading-like task. Third, the self-reported strategies of the participants were also analyzed. All three parts of this study point towards the same conclusion according to which during music score reading, the musician most likely first translates the visual score into an auditory cue, probably starting around 700 or 1300 ms, ready for storage and delayed comparison with the auditory feedback.

  10. Adaptive fuzzy output-feedback controller design for nonlinear time-delay systems with unknown control direction.

    Science.gov (United States)

    Hua, Chang-Chun; Wang, Qing-Guo; Guan, Xin-Ping

    2009-04-01

    In this paper, the robust-control problem is investigated for a class of uncertain nonlinear time-delay systems via dynamic output-feedback approach. The considered system is in the strict-feedback form with unknown control direction. A full-order observer is constructed with the gains computed via linear matrix inequality at first. Then, with the bounds of uncertain functions known, we design the dynamic output-feedback controller such that the closed-loop system is asymptotically stable. Furthermore, when the bound functions of uncertainties are not available, the adaptive fuzzy-logic system is employed to approximate the uncertain function, and the corresponding output-feedback controller is designed. It is shown that the resulting closed-loop system is stable in the sense of semiglobal uniform ultimate boundedness. Finally, simulations are done to verify the feasibility and effectiveness of the obtained theoretical results.

  11. Error-resilient low-delay H.264/802.11 transmission via cross-layer coding with feedback channel

    Science.gov (United States)

    Chiew, Tuan-Kiang; Hill, Paul; Ferre, Pierre; Agrafiotis, Dimitris; Chung-How, James T. H.; Nix, Andy; Bull, David R.

    2005-07-01

    We propose a method of providing error resilient H.264 video over 802.11 wireless channels by using a feedback mechanism which does not incur an additional delay typically found in ARQ-type feedback. Our system uses the TCP/IP and UDP/IP protocols, located between the medium access control (MAC) layer of 802.11, and the H.264 video application layer. The UDP protocol is used to transfer time sensitive video data without delay; however, packet losses introduce excessive artifacts which propagate to subsequent frames. Error resilience is achieved by a feedback mechanism-the decoder conveys the packet-loss information as small TCP packets to the video source as negative acknowledgements. By using multiple reference frames, slice-based coding and timely intra-refresh, the encoder makes use of this feedback information to perform subsequent temporal prediction without propagating the error to future frames. We take static measurements of the actual channel and use the packet loss and delay patterns to test our algorithms. Simulations show an improvement of 0.5~5 dB in PSNR over plain UDP-based video transmission. Our method improves the overall quality of service of interactive video transmission over wireless LAN; it can be used as a model for future media-aware wireless network protocol designs.

  12. Dynamic Analysis of a High-Static-Low-Dynamic-Stiffness Vibration Isolator with Time-Delayed Feedback Control

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2015-01-01

    Full Text Available This paper proposes the time-delayed cubic velocity feedback control strategy to improve the isolation performance of High-Static-Low-Dynamic-Stiffness (HSLDS vibration isolator. Firstly, the primary resonance of the controlled HSLDS vibration isolator is obtained by using multiple scales method. The equivalent damping ratio and equivalent resonance frequency are defined to study the effects of feedback gain and time delay on the primary resonance. The jump phenomenon analysis of the controlled system without and with time delay is investigated by using Sylvester resultant method and optimization method, respectively. The stability analysis of the controlled system is also considered. Then, the 1/3 subharmonic resonance of the controlled system is studied by using multiple scales method. The effects of feedback gain and time delay on the 1/3 subharmonic resonance are also presented. Finally, force transmissibility is proposed to evaluate the performance of the controlled system and compared with an equivalent linear passive vibration isolator. The results show that the vibration amplitude of the controlled system around the resonance frequency region decreases and the isolation frequency band is larger compared to the equivalent one. A better isolation performance in the high frequency band can be achieved compared to the passive HSLDS vibration isolator.

  13. Effect of feedback on delaying deterioration in quality of compressions during 2 minutes of continuous chest compressions: a randomized manikin study investigating performance with and without feedback

    Directory of Open Access Journals (Sweden)

    Lyngeraa Tobias

    2012-02-01

    Full Text Available Abstract Background Good quality basic life support (BLS improves outcome following cardiac arrest. As BLS performance deteriorates over time we performed a parallel group, superiority study to investigate the effect of feedback on quality of chest compression with the hypothesis that feedback delays deterioration of quality of compressions. Methods Participants attending a national one-day conference on cardiac arrest and CPR in Denmark were randomized to perform single-rescuer BLS with (n = 26 or without verbal and visual feedback (n = 28 on a manikin using a ZOLL AED plus. Data were analyzed using Rescuenet Code Review. Blinding of participants was not possible, but allocation concealment was performed. Primary outcome was the proportion of delivered compressions within target depth compared over a 2-minute period within the groups and between the groups. Secondary outcome was the proportion of delivered compressions within target rate compared over a 2-minute period within the groups and between the groups. Performance variables for 30-second intervals were analyzed and compared. Results 24 (92% and 23 (82% had CPR experience in the group with and without feedback respectively. 14 (54% were CPR instructors in the feedback group and 18 (64% in the group without feedback. Data from 26 and 28 participants were analyzed respectively. Although median values for proportion of delivered compressions within target depth were higher in the feedback group (0-30 s: 54.0%; 30-60 s: 88.0%; 60-90 s: 72.6%; 90-120 s: 87.0%, no significant difference was found when compared to without feedback (0-30 s: 19.6%; 30-60 s: 33.1%; 60-90 s: 44.5%; 90-120 s: 32.7% and no significant deteriorations over time were found within the groups. In the feedback group a significant improvement was found in the proportion of delivered compressions below target depth when the subsequent intervals were compared to the first 30 seconds (0-30 s: 3.9%; 30-60 s: 0.0%; 60-90 s: 0

  14. Further results on global state feedback stabilization of high-order nonlinear systems with time-varying delays.

    Science.gov (United States)

    Gao, Fangzheng; Wu, Yuqiang

    2015-03-01

    This paper considers the problem of global stabilization by state feedback for a class of high-order nonlinear systems with time-varying delays. Comparing with the existing relevant literature, the systems under investigation allow more uncertainties, to which the existing control methods are inapplicable. By introducing sign function and necessarily modifying the method of adding a power integrator, a state feedback controller is successfully constructed to preserve the equilibrium at the origin and guarantee the global asymptotic stability of the resulting closed-loop system. Finally, two simulation examples are provided to illustrate the effectiveness of the proposed approach.

  15. Finite-time robust stabilization of uncertain delayed neural networks with discontinuous activations via delayed feedback control.

    Science.gov (United States)

    Wang, Leimin; Shen, Yi; Sheng, Yin

    2016-04-01

    This paper is concerned with the finite-time robust stabilization of delayed neural networks (DNNs) in the presence of discontinuous activations and parameter uncertainties. By using the nonsmooth analysis and control theory, a delayed controller is designed to realize the finite-time robust stabilization of DNNs with discontinuous activations and parameter uncertainties, and the upper bound of the settling time functional for stabilization is estimated. Finally, two examples are provided to demonstrate the effectiveness of the theoretical results.

  16. Control of Halo-Chaos in Beam Transport Network via Neural Network Adaptation with Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; LUO Xiao-Shu; HUANG Guo-Xian

    2006-01-01

    Subject of the halo-chaos control in beam transport networks (channels) has become a key concerned issue for many important applications of high-current proton beam since 1990'. In this paper, the magnetic field adaptive control based on the neuralnetwork with time-delayed feedback is proposed for suppressing beam halo-chaos in the beam transport network with periodic focusing channels. The envelope radius of high-current proton beam is controlled to reach the matched beam radius by suitably selecting the control structure and parameter of the neural network, adjusting the delayed-time and control coefficient of the neural network.

  17. Robust Output Feedback Control for Active Seat Suspension Systems with Actuator Time Delay Using µ-Synthesis Approach

    Directory of Open Access Journals (Sweden)

    Mohammad Gudarzi

    2013-10-01

    Full Text Available This study presents a robust output feedback optimal H&infin control synthesis for a class of uncertain seat suspension systems with actuator saturation and an uncertain actuator time delay. A vertical vibration model of human body is added in order to make the modeling of seat suspension systems more accurate. A dynamic controller is considered by using of two measurable states of the model, by real sensors, as output feedback. Moreover, uncertain actuator time delay is considered to guarantee robust performance of the closed-loop system. The controller is derived by using D-K iteration algorithm for constrained systems with norm-bounded uncertainties. The corresponding closed-loop system is asymptotically stable with a guaranteed H&infin performance. Finally, a design example is presented to show the performance and robustness of the developed theoretical results.

  18. Outage probability of dual-hop partial relay selection with feedback delay in the presence of interference

    KAUST Repository

    Al-Qahtani, Fawaz S.

    2011-09-01

    In this paper, we investigate the outage performance of a dual-hop relaying systems with partial relay selection and feedback delay. The analysis considers the case of Rayleigh fading channels when the relaying station as well as the destination undergo mutually independent interfering signals. Particularly, we derive the cumulative distribution function (c.d.f.) of a new type of random variable involving sum of multiple independent exponential random variables, based on which, we present closed-form expressions for the exact outage probability of a fixed amplify-and-forward (AF) and decode-and-forward (DF) relaying protocols. Numerical results are provided to illustrate the joint effect of the delayed feedback and co-channel interference on the outage probability. © 2011 IEEE.

  19. The Effect of Feedback Delay and Feedback Type on Perceptual Category Learning: The Limits of Multiple Systems

    Science.gov (United States)

    Dunn, John C.; Newell, Ben R.; Kalish, Michael L.

    2012-01-01

    Evidence that learning rule-based (RB) and information-integration (II) category structures can be dissociated across different experimental variables has been used to support the view that such learning is supported by multiple learning systems. Across 4 experiments, we examined the effects of 2 variables, the delay between response and feedback…

  20. Note on the Persistence of a Nonautonomous Lotka-Volterra Competitive System with Infinite Delay and Feedback Controls

    Directory of Open Access Journals (Sweden)

    Chunling Shi

    2014-01-01

    Full Text Available We study a nonautonomous Lotka-Volterra competitive system with infinite delay and feedback controls. We establish a series of criteria under which a part of n-species of the systems is driven to extinction while the remaining part of the species is persistent. Particularly, as a special case, a series of new sufficient conditions on the persistence for all species of system are obtained. Several examples together with their numerical simulations show the feasibility of our main results.

  1. Rolling bearing fault diagnosis based on time-delayed feedback monostable stochastic resonance and adaptive minimum entropy deconvolution

    Science.gov (United States)

    Li, Jimeng; Li, Ming; Zhang, Jinfeng

    2017-08-01

    Rolling bearings are the key components in the modern machinery, and tough operation environments often make them prone to failure. However, due to the influence of the transmission path and background noise, the useful feature information relevant to the bearing fault contained in the vibration signals is weak, which makes it difficult to identify the fault symptom of rolling bearings in time. Therefore, the paper proposes a novel weak signal detection method based on time-delayed feedback monostable stochastic resonance (TFMSR) system and adaptive minimum entropy deconvolution (MED) to realize the fault diagnosis of rolling bearings. The MED method is employed to preprocess the vibration signals, which can deconvolve the effect of transmission path and clarify the defect-induced impulses. And a modified power spectrum kurtosis (MPSK) index is constructed to realize the adaptive selection of filter length in the MED algorithm. By introducing the time-delayed feedback item in to an over-damped monostable system, the TFMSR method can effectively utilize the historical information of input signal to enhance the periodicity of SR output, which is beneficial to the detection of periodic signal. Furthermore, the influence of time delay and feedback intensity on the SR phenomenon is analyzed, and by selecting appropriate time delay, feedback intensity and re-scaling ratio with genetic algorithm, the SR can be produced to realize the resonance detection of weak signal. The combination of the adaptive MED (AMED) method and TFMSR method is conducive to extracting the feature information from strong background noise and realizing the fault diagnosis of rolling bearings. Finally, some experiments and engineering application are performed to evaluate the effectiveness of the proposed AMED-TFMSR method in comparison with a traditional bistable SR method.

  2. Frequency-domain criterion for the chaos synchronization of time-delay power systems under linear feedback control

    Indian Academy of Sciences (India)

    Qian Lin; Xiaofeng Wu; Yun Chen

    2015-12-01

    This paper studies the global synchronization of non-autonomous, time-delay, chaotic power systems via linear state-error feedback control. The frequency domain criterion and the LMI criterion are proposed and applied to design the coupling matrix. Some algebraic criteria via a single-variable linear coupling are derived and formulated in simple algebraic inequalities. The effectiveness of the new criteria is illustrated with numerical examples.

  3. Auditory short-term memory activation during score reading

    OpenAIRE

    Simoens, Veerle L; Mari Tervaniemi

    2013-01-01

    Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during ...

  4. Rotation Modes Stability Analysis and Phase Compensation for Magnetically Suspended Flywheel Systems with Cross Feedback Controller and Time Delay

    Directory of Open Access Journals (Sweden)

    Yuan Ren

    2016-01-01

    Full Text Available This paper analyzes the effects of time delay on the stability of the rotation modes for the magnetically suspended flywheel (MSFW with strong gyroscopic effects. A multi-input multioutput system is converted into a single-input single-output control system with complex coefficient by variable reconstruction, and the stability equivalence of the systems before and after variable reconstruction is proven. For the rotation modes, the stability limits and corresponding vibration frequencies are found as a function of nondimensional magnetic stiffness and damping and nondimensional parameters of rotor speed and time delay. Additionally, the relationship between cross feedback control system stability and time delay is investigated. And an effective phase compensation method based on cross-channel is further presented. Simulation and experimental results are presented to demonstrate the correctness of the stability analysis method and the superiority of the phase compensation strategy.

  5. Exponential Admissibility and Dynamic Output Feedback Control of Switched Singular Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Jinxing Lin

    2010-01-01

    Full Text Available This paper is concerned with the problems of exponential admissibility and dynamic output feedback (DOF control for a class of continuous-time switched singular systems with interval time-varying delay. A full-order, dynamic, synchronously switched DOF controller is considered. First, by using the average dwell time approach, a delay-range-dependent exponential admissibility criterion for the unforced switched singular time-delay system is established in terms of linear matrix inequalities (LMIs. Then, based on this criterion, a sufficient condition on the existence of a desired DOF controller, which guarantees that the closed-loop system is regular, impulse free and exponentially stable, is proposed by employing the LMI technique. Finally, some illustrative examples are given to show the effectiveness of the proposed approach.

  6. Auditory feedback of one’s own voice is used for high-level semantic monitoring: the self-comprehension hypothesis

    Directory of Open Access Journals (Sweden)

    Andreas eLind

    2014-03-01

    Full Text Available What would it be like if we said one thing, and heard ourselves saying something else? Would we notice something was wrong? Or would we believe we said the thing we heard? Is feedback of our own speech only used to detect errors, or does it also help to specify the meaning of what we say? Comparator models of self-monitoring favor the first alternative, and hold that our sense of agency is given by the comparison between intentions and outcomes, while inferential models argue that agency is a more fluent construct, dependent on contextual inferences about the most likely cause of an action. In this paper, we present a theory about the use of feedback during speech. Specifically, we discuss inferential models of speech production that question the standard comparator assumption that the meaning of our utterances is fully specified before articulation. We then argue that auditory feedback provides speakers with a channel for high-level, semantic self-comprehension. In support of this we discuss results using a method we recently developed called Real-time Speech Exchange (RSE. In our first study using RSE (Lind et al, submitted participants were fitted with headsets and performed a computerized Stroop task. We surreptitiously recorded words they said, and later in the test we played them back at the exact same time that the participants uttered something else, while blocking the actual feedback of their voice. Thus, participants said one thing, but heard themselves saying something else. The results showed that when timing conditions were ideal, more than two thirds of the manipulations went undetected. Crucially, in a large proportion of the non-detected manipulated trials, the inserted words were experienced as self-produced by the participants. This indicates that our sense of agency for speech has a strong inferential component, and that auditory feedback of our own voice acts as a pathway for semantic monitoring.

  7. Delayed, but not immediate, feedback after multiple-choice questions increases performance on a subsequent short-answer, but not multiple-choice, exam: evidence for the dual-process theory of memory.

    Science.gov (United States)

    Sinha, Neha; Glass, Arnold Lewis

    2015-01-01

    Three experiments, two performed in the laboratory and one embedded in a college psychology lecture course, investigated the effects of immediate versus delayed feedback following a multiple-choice exam on subsequent short answer and multiple-choice exams. Performance on the subsequent multiple-choice exam was not affected by the timing of the feedback on the prior exam; however, performance on the subsequent short answer exam was better following delayed than following immediate feedback. This was true regardless of the order in which immediate versus delayed feedback was given. Furthermore, delayed feedback only had a greater effect than immediate feedback on subsequent short answer performance following correct, confident responses on the prior exam. These results indicate that delayed feedback cues a student's prior response and increases subsequent recollection of that response. The practical implication is that delayed feedback is better than immediate feedback during academic testing.

  8. Non-fragile multi-objective static output feedback control of vehicle active suspension with time-delay

    Science.gov (United States)

    Kong, Yongsu; Zhao, Dingxuan; Yang, Bin; Han, Chenghao; Han, Kyongwon

    2014-07-01

    This paper presents an approach to design a delay-dependent non-fragile H∞/L2-L∞ static output feedback (SOF) controller for active suspension with input time-delay. The control problem of quarter-car active suspension with actuator time-delay is formulated to a H∞/L2-L∞ control problem. By employing a delay-dependent Lyapunov function, new existence conditions of delay-dependent non-fragile SOF H∞ controller and L2-L∞ controller are derived, respectively, in terms of the feasibility of bilinear matrix inequalities (BMIs). Then, a procedure based on linear matrix inequality optimisation and a hybrid algorithm of the particle swarm optimisation and differential evolution is used to solve an optimisation problem with BMI constraints. Design and simulation results of non-fragile H∞/L2-L∞ controller for active suspension show that the designed controller not only can achieve the optimal performance and stability of the closed-loop system in spite of the existence of the actuator time-delay, but also has significantly improved the non-fragility characteristics over controller perturbations.

  9. Tracking with asymptotic sliding mode and adaptive input delay effect compensation of nonlinearly perturbed delayed systems applied to traffic feedback control

    Science.gov (United States)

    Mirkin, Boris; Haddad, Jack; Shtessel, Yuri

    2016-09-01

    Asymptotical sliding mode-model reference adaptive control design for a class of systems with parametric uncertainty, unknown nonlinear perturbation and external disturbance, and with known input and state delays is proposed. To overcome the difficulty to directly predict the plant state under uncertainties, a control design is based on a developed decomposition procedure, where a 'generalised error' in conjunction with auxiliary linear dynamic blocks with adjustable gains is introduced and the sliding variable is formed on the basis of this error. The effect of such a decomposition is to pull the input delay out of first step of the design procedure. As a result, similarly to the classical Smith predictor, the adaptive control architecture based only on the lumped-delays, i.e. without conventional in such cases difficult-implemented distributed-delay blocks. Two new adaptive control schemes are proposed. A linearisation-based control design is constructed for feedback control of an urban traffic region model with uncertain dynamics. Simulation results demonstrate the effectiveness of the developed adaptive control method.

  10. Feedback.

    Science.gov (United States)

    Richardson, Barbara K

    2004-12-01

    The emergency department provides a rich environment for diverse patient encounters, rapid clinical decision making, and opportunities to hone procedural skills. Well-prepared faculty can utilize this environment to teach residents and medical students and gain institutional recognition for their incomparable role and teamwork. Giving effective feedback is an essential skill for all teaching faculty. Feedback is ongoing appraisal of performance based on direct observation aimed at changing or sustaining a behavior. Tips from the literature and the author's experience are reviewed to provide formats for feedback, review of objectives, and elements of professionalism and how to deal with poorly performing students. Although the following examples pertain to medical student education, these techniques are applicable to the education of all adult learners, including residents and colleagues. Specific examples of redirection and reflection are offered, and pitfalls are reviewed. Suggestions for streamlining verbal and written feedback and obtaining feedback from others in a fast-paced environment are given. Ideas for further individual and group faculty development are presented.

  11. Anti-Swing Control of Gantry and Tower Cranes Using Fuzzy and Time-Delayed Feedback with Friction Compensation

    Directory of Open Access Journals (Sweden)

    H.M. Omar

    2005-01-01

    Full Text Available We designed a feedback controller to automate crane operations by controlling the load position and its swing. First, a PD tracking controller is designed to follow a prescribed trajectory. Then, another controller is added to the control loop to damp the load swing. The anti-swing controller is designed based on two techniques: a time-delayed feedback of the load swing angle and an anti-swing fuzzy logic controller (FLC. The rules of the FLC are generated by mapping the performance of the time-delayed feedback controller. The same mapping method used for generating the rules can be applied to mimic the performance of an expert operator. The control algorithms were designed for gantry cranes and then extended to tower cranes by considering the coupling between the translational and rotational motions. Experimental results show that the controller is effective in reducing load oscillations and transferring the load in a reasonable time. To experimentally validate the theory, we had to compensate for friction. To this end, we estimated the friction and then applied a control action to cancel it. The friction force was estimated by assuming a mathematical model and then estimating the model coefficients using an off-line identification technique, the method of least squares (LS.

  12. Emergence of resonant mode-locking via delayed feedback in quantum dot semiconductor lasers.

    Science.gov (United States)

    Tykalewicz, B; Goulding, D; Hegarty, S P; Huyet, G; Erneux, T; Kelleher, B; Viktorov, E A

    2016-02-22

    With conventional semiconductor lasers undergoing external optical feedback, a chaotic output is typically observed even for moderate levels of the feedback strength. In this paper we examine single mode quantum dot lasers under strong optical feedback conditions and show that an entirely new dynamical regime is found consisting of spontaneous mode-locking via a resonance between the relaxation oscillation frequency and the external cavity repetition rate. Experimental observations are supported by detailed numerical simulations of rate equations appropriate for this laser type. The phenomenon constitutes an entirely new mode-locking mechanism in semiconductor lasers.

  13. Feedback Control Variables Have No Influence on the Permanence of a Discrete n-Species Schoener Competition System with Time Delays

    Directory of Open Access Journals (Sweden)

    Qianqian Su

    2010-01-01

    Full Text Available We consider a discrete n-species Schoener competition system with time delays and feedback controls. By using difference inequality theory, a set of conditions which guarantee the permanence of system is obtained. The results indicate that feedback control variables have no influence on the persistent property of the system. Numerical simulations show the feasibility of our results.

  14. Constant Delivery Delay Protocol Sequences for the Collision Channel Without Feedback

    OpenAIRE

    Salaun, Lou; Shue Chen, Chung; Chen, Yi; Shing Wong, Wing

    2016-01-01

    International audience; We consider a collision channel model without feedback based on a time-slotted communication channel shared by K users. In this model, packets transmitted in the same time slot collide with each other and are unrecoverable. Each user accesses the channel according to an internal periodical pattern called protocol sequence. Due to the lack of feedback, users cannot synchronize their protocol sequences, leading to unavoidable collisions and varying throughput. Protocol s...

  15. Reduced-order observer-based output feedback control of nonlinear time-delay systems with prescribed performance

    Science.gov (United States)

    Hua, Changchun; Zhang, Liuliu; Guan, Xinping

    2016-04-01

    This paper studies the problem of output feedback control for a class of nonlinear time-delay systems with prescribed performance. The system is in the form of triangular structure with unmodelled dynamics. First, we introduce a reduced-order observer to provide the estimate of the unmeasured states. Then, by setting a new condition with the performance function, we design the state transformation with prescribed performance control. By employing backstepping method, we construct the output feedback controller. It is proved that the resulting closed-loop system is asymptotically stable and both transient and steady-state performance of the output are preserved with the changing supply function idea. Finally, a simulation example is conducted to show the effectiveness of the main results.

  16. Non-fragile H∞ dynamic output feedback control for uncertain Takagi-Sugeno fuzzy systems with time-varying delay

    Science.gov (United States)

    Huang, Sheng-Juan; Yang, Guang-Hong

    2016-09-01

    This paper mainly focuses on the problem of non-fragile H∞ dynamic output feedback control for a class of uncertain Takagi-Sugeno fuzzy systems with time-varying state delay. Based on a new type of Lyapunov-Krasovskii functional without ignoring any subtle integral terms in the derivatives, a less conservative dynamic output feedback controller with additive gain variations is designed, which guarantees that the closed-loop fuzzy system is asymptotically stable and satisfies a prescribed H∞-performance level. Furthermore, the obtained parameter-dependent conditions are given in terms of solution to a set of linear matrix inequalities, which improve some existing relevant results. Finally, numerical examples are given to illustrate the effectiveness and merits of the proposed method.

  17. Delayed coupling to feedback inhibition during a critical period for the integration of adult-born granule cells.

    Science.gov (United States)

    Temprana, Silvio G; Mongiat, Lucas A; Yang, Sung M; Trinchero, Mariela F; Alvarez, Diego D; Kropff, Emilio; Giacomini, Damiana; Beltramone, Natalia; Lanuza, Guillermo M; Schinder, Alejandro F

    2015-01-07

    Developing granule cells (GCs) of the adult dentate gyrus undergo a critical period of enhanced activity and synaptic plasticity before becoming mature. The impact of developing GCs on the activity of preexisting dentate circuits remains unknown. Here we combine optogenetics, acute slice electrophysiology, and in vivo chemogenetics to activate GCs at different stages of maturation to study the recruitment of local target networks. We show that immature (4-week-old) GCs can efficiently drive distal CA3 targets but poorly activate proximal interneurons responsible for feedback inhibition (FBI). As new GCs transition toward maturity, they reliably recruit GABAergic feedback loops that restrict spiking of neighbor GCs, a mechanism that would promote sparse coding. Such inhibitory loop impinges only weakly in new cohorts of young GCs. A computational model reveals that the delayed coupling of new GCs to FBI could be crucial to achieve a fine-grain representation of novel inputs in the dentate gyrus.

  18. Stochastic thermodynamics of Langevin systems under time-delayed feedback control. II. Nonequilibrium steady-state fluctuations

    Science.gov (United States)

    Rosinberg, M. L.; Tarjus, G.; Munakata, T.

    2017-02-01

    This paper is the second in a series devoted to the study of Langevin systems subjected to a continuous time-delayed feedback control. The goal of our previous paper [Phys. Rev. E 91, 042114 (2015), 10.1103/PhysRevE.91.042114] was to derive second-law-like inequalities that provide bounds to the average extracted work. Here we study stochastic fluctuations of time-integrated observables such as the heat exchanged with the environment, the extracted work, or the (apparent) entropy production. We use a path-integral formalism and focus on the long-time behavior in the stationary cooling regime, stressing the role of rare events. This is illustrated by a detailed analytical and numerical study of a Langevin harmonic oscillator driven by a linear feedback.

  19. Asynchronous H∞ Dynamic Output Feedback Control of Switched Time-Delay Systems with Sensor Nonlinearity and Missing Measurements

    Directory of Open Access Journals (Sweden)

    Jiwei Wen

    2014-01-01

    Full Text Available The H∞ dynamic output feedback control problem for a class of discrete-time switched time-delay systems under asynchronous switching is investigated in this paper. Sensor nonlinearity and missing measurements are considered when collecting output knowledge of the system. Firstly, when there exists asynchronous switching between the switching modes and the candidate controllers, new results on the regional stability and l2 gain analysis for the underlying system are given by allowing the Lyapunov-like function (LLF to increase with a random probability. Then, a mean square stabilizing output feedback controller and a switching law subject to average dwell time (ADT are obtained with a given disturbance attenuation level. Moreover, the mean square domain of attraction could be estimated by a convex combination of a set of ellipsoids, the number of which depends on the number of switching modes. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.

  20. Rehabilitation of the Upper Extremity after Stroke: A Case Series Evaluating REO Therapy and an Auditory Sensor Feedback for Trunk Control

    Directory of Open Access Journals (Sweden)

    G. Thielman

    2012-01-01

    Full Text Available Background and Purpose. Training in the virtual environment in post stroke rehab is being established as a new approach for neurorehabilitation, specifically, ReoTherapy (REO a robot-assisted virtual training device. Trunk stabilization strapping has been part of the concept with this device, and literature is lacking to support this for long-term functional changes with individuals after stroke. The purpose of this case series was to measure the feasibility of auditory trunk sensor feedback during REO therapy, in moderate to severely impaired individuals after stroke. Case Description. Using an open label crossover comparison design, 3 chronic stroke subjects were trained for 12 sessions over six weeks on either the REO or the control condition of task related training (TRT; after a washout period of 4 weeks; the alternative therapy was given. Outcomes. With both interventions, clinically relevant improvements were found for measures of body function and structure, as well as for activity, for two participants. Providing auditory feedback during REO training for trunk control was found to be feasible. Discussion. The degree of changes evident varied per protocol and may be due to the appropriateness of the technique chosen, as well as based on patients impaired arm motor control.

  1. Parametrically Excited Oscillations of Second-Order Functional Differential Equations and Application to Duffing Equations with Time Delay Feedback

    Directory of Open Access Journals (Sweden)

    Mervan Pašić

    2014-01-01

    Full Text Available We study oscillatory behaviour of a large class of second-order functional differential equations with three freedom real nonnegative parameters. According to a new oscillation criterion, we show that if at least one of these three parameters is large enough, then the main equation must be oscillatory. As an application, we study a class of Duffing type quasilinear equations with nonlinear time delayed feedback and their oscillations excited by the control gain parameter or amplitude of forcing term. Finally, some open questions and comments are given for the purpose of further study on this topic.

  2. Memory State-Feedback Stabilization for a Class of Time-Delay Systems with a Type of Adaptive Strategy

    Directory of Open Access Journals (Sweden)

    Lin Chai

    2013-01-01

    Full Text Available Stabilization of a class of systems with time delay is studied using adaptive control. With the help of the “error to error” technique and the separated “descriptor form” technique, the memory state-feedback controller is designed. The adaptive controller designed can guarantee asymptotical stability of the closed-loop system via a suitable Lyapunov-Krasovskii functional. Some sufficient conditions are derived for the stabilization together with the linear matrix inequality (LMI design approach. Finally, the effectiveness of the proposed control design methodology is demonstrated in numerical simulations.

  3. Finite-time H∞ control for a class of discrete-time switched time-delay systems with quantized feedback

    Science.gov (United States)

    Song, Haiyu; Yu, Li; Zhang, Dan; Zhang, Wen-An

    2012-12-01

    This paper is concerned with the finite-time quantized H∞ control problem for a class of discrete-time switched time-delay systems with time-varying exogenous disturbances. By using the sector bound approach and the average dwell time method, sufficient conditions are derived for the switched system to be finite-time bounded and ensure a prescribed H∞ disturbance attenuation level, and a mode-dependent quantized state feedback controller is designed by solving an optimization problem. Two illustrative examples are provided to demonstrate the effectiveness of the proposed theoretical results.

  4. A recursive delayed output-feedback control to stabilize chaotic systems using linear-in-parameter neural networks

    Science.gov (United States)

    Yadmellat, Peyman; Nikravesh, S. Kamaleddin Yadavar

    2011-01-01

    In this paper, a recursive delayed output-feedback control strategy is considered for stabilizing unstable periodic orbit of unknown nonlinear chaotic systems. An unknown nonlinearity is directly estimated by a linear-in-parameter neural network which is then used in an observer structure. An on-line modified back propagation algorithm with e-modification is used to update the weights of the network. The globally uniformly ultimately boundedness of overall closed-loop system response is analytically ensured using Razumikhin lemma. To verify the effectiveness of the proposed observer-based controller, a set of simulations is performed on a Rossler system in comparison with several previous methods.

  5. The Feedback Control Strategy of the Takagi-Sugeno Fuzzy Car-Following Model with Two Delays

    Directory of Open Access Journals (Sweden)

    Cong Zhai

    2016-01-01

    Full Text Available Considering the driver’s sensing the headway and velocity the different time-varying delays exist, respectively, and the sensitivity of drivers changes with headway and speed. Introducing the fuzzy control theory, a new fuzzy car-following model with two delays is presented, and the feedback control strategy of the new fuzzy car-following model is studied. Based on the Lyapunov function theory and linear matrix inequality (LMI approach, the sufficient condition that the existence of the fuzzy controller is given making the closed-loop system is asymptotic, stable; namely, traffic congestion phenomenon can effectively be suppressed, and the controller gain matrix can be obtained via solving linear matrix inequality. Finally, the simulation examples verify that the method which suppresses traffic congestion and reduces fuel consumption and exhaust emissions is effective.

  6. Decentralized Output Feedback Adaptive NN Tracking Control for Time-Delay Stochastic Nonlinear Systems With Prescribed Performance.

    Science.gov (United States)

    Hua, Changchun; Zhang, Liuliu; Guan, Xinping

    2015-11-01

    This paper studies the dynamic output feedback tracking control problem for stochastic interconnected time-delay systems with the prescribed performance. The subsystems are in the form of triangular structure. First, we design a reduced-order observer independent of time delay to estimate the unmeasured state variables online instead of the traditional full-order observer. Then, a new state transformation is proposed in consideration of the prescribed performance requirement. Using neural network to approximate the composite unknown nonlinear function, the corresponding decentralized output tracking controller is designed. It is strictly proved that the resulting closed-loop system is stable in probability in the sense of uniformly ultimately boundedness and that both transient-state and steady-state performances are preserved. Finally, a simulation example is given, and the result shows the effectiveness of the proposed control design method.

  7. Adaptive neural tracking control of a class of MIMO pure-feedback time-delay nonlinear systems with input saturation

    Science.gov (United States)

    Yang, Yang; Yue, Dong; Yuan, Deming

    2016-11-01

    Considering interconnections among subsystems, we propose an adaptive neural tracking control scheme for a class of multiple-input-multiple-output (MIMO) non-affine pure-feedback time-delay nonlinear systems with input saturation. Neural networks (NNs) are employed to approximate unknown functions in the design procedure, and the separation technology is introduced here to tackle the problem induced from unknown time-delay items. The adaptive neural tracking control scheme is constructed by combining Lyapunov-Krasovskii functionals, NNs, the auxiliary system, the implicit function theory and the mean value theorem along with the dynamic surface control technique. Also, it is proven that the strategy guarantees tracking errors converge to a small neighbourhood around the origin by appropriate choice of design parameters and all signals in the closed-loop system uniformly ultimately bounded. Numerical simulation results are presented to demonstrate the effectiveness of the proposed control strategy.

  8. Bifurcation structure of cavity soliton dynamics in a vertical-cavity surface-emitting laser with a saturable absorber and time-delayed feedback

    Science.gov (United States)

    Schelte, Christian; Panajotov, Krassimir; Tlidi, Mustapha; Gurevich, Svetlana V.

    2017-08-01

    We consider a wide-aperture surface-emitting laser with a saturable absorber section subjected to time-delayed feedback. We adopt the mean-field approach assuming a single longitudinal mode operation of the solitary vertical-cavity surface-emitting laser (VCSEL). We investigate cavity soliton dynamics under the effect of time-delayed feedback in a self-imaging configuration where diffraction in the external cavity is negligible. Using bifurcation analysis, direct numerical simulations, and numerical path-continuation methods, we identify the possible bifurcations and map them in a plane of feedback parameters. We show that for both the homogeneous and localized stationary lasing solutions in one spatial dimension, the time-delayed feedback induces complex spatiotemporal dynamics, in particular a period doubling route to chaos, quasiperiodic oscillations, and multistability of the stationary solutions.

  9. Unified stabilizing controller synthesis approach for discrete-time intelligent systems with time delays by dynamic output feedback

    Institute of Scientific and Technical Information of China (English)

    LIU MeiQin

    2007-01-01

    A novel model, termed the standard neural network model (SNNM), is advanced to describe some delayed (or non-delayed) discrete-time intelligent systems composed of neural networks and Takagi and Sugeno (T-S) fuzzy models. The SNNM is composed of a discrete-time linear dynamic system and a bounded static nonlinear operator. Based on the global asymptotic stability analysis of the SNNMs, linear and nonlinear dynamic output feedback controllers are designed for the SNNMs to stabilize the closed-loop systems, respectively. The control design equations are shown to be a set of linear matrix inequalities (LMIs) which can be easily solved by various convex optimization algorithms to determine the control signals. Most neural-network-based (or fuzzy) discrete-time intelligent systems with time delays or without time delays can be transformed into the SNNMs for controller synthesis in a unified way. Three application examples show that the SNNMs not only make controller synthesis of neural-network-based (or fuzzy) discrete-time intelligent systems much easier, but also provide a new approach to the synthesis of the controllers for the other type of nonlinear systems.

  10. Stability result of the Timoshenko system with delay and boundary feedback

    KAUST Repository

    Said-Houari, Belkacem

    2012-01-06

    Our interest in this paper is to analyse the asymptotic behaviour of a Timoshenko beam system together with two boundary controls, with delay terms in the first and second equation. Assuming the weights of the delay are small enough, we show that the system is well-posed using the semigroup theory. Furthermore, we introduce a Lyapunov functional that gives the exponential decay of the total energy. © 2012 The author.

  11. The effect and design of time delay in feedback control for a nonlinear isolation system

    Science.gov (United States)

    Sun, Xiuting; Xu, Jian; Fu, Jiangsong

    2017-03-01

    The optimum value of time delay of active control used in a nonlinear isolation system for different types of external excitation is studied in this paper. Based on the mathematical model of the nonlinear isolator with time-delayed active control, the stability, response and displacement transmissibility of the system are analyzed to obtain the standards for appropriate values of time delay and control strengths. The effects of nonlinearity and time delay on the stability and vibration response are discussed in details. For impact excitation and random excitation, the optimal value of time delay is obtained based on the vibration dissipation time via eigenvalues analysis, while for harmonic excitation, the optimal values are determined based on multiple vibration properties including natural frequency, amplitude death region and effective isolation region by the Averaging Method. This paper establishes the relationship between the parameters and vibration properties of a nonlinear isolation system which provides the guidance for optimizing time-delayed active control for different types of excitation in engineering practices.

  12. Resonances of a nonlinear single-degree-of-freedom system with time delay in linear feedback control

    Energy Technology Data Exchange (ETDEWEB)

    El-Bassiouny, Atef F. [Mathematics Dept., Benha Univ., Benha (Egypt); El-Kholy, Salah [Dept. of Mathematics, Menoufia Univ., Shebin El-kom (Egypt)

    2010-05-15

    The primary and subharmonic resonances of a nonlinear single-degree-of-freedom system under feedback control with a time delay are studied by means of an asymptotic perturbation technique. Both external (forcing) and parametric excitations are included. By means of the averaging method and multiple scales method, two slow-flow equations for the amplitude and phase of the primary and subharmonic resonances and all other parameters are obtained. The steady state (fixed points) corresponding to a periodic motion of the starting system is investigated and frequency-response curves are shown. The stability of the fixed points is examined using the variational method. The effect of the feedback gains, the time-delay, the coefficient of cubic term, and the coefficients of external and parametric excitations on the steady-state responses are investigated and the results are presented as plots of the steady-state response amplitude versus the detuning parameter. The results obtained by two methods are in excellent agreement. (orig.)

  13. Semiconductor ring lasers with delayed optical feedback: low-frequency fluctuations

    Science.gov (United States)

    Van der Sande, Guy; Mashal, Lilia; Nguimdo, Romain Modeste; Cornelles-Soriano, Miguel C.; Danckaert, Jan; Verschaffelt, Guy

    2014-05-01

    Semiconductor lasers subject to external feedback are known to exhibit a wide variety of dynamical regimes desired for some applications such as chaos cryptography, random bit generation, and reservoir computing. Low-frequency fluctuations is one of the most frequently encountered regimes. It is characterized by a fast drop in laser intensity followed by a gradual recovery. The duration of this recovery process is irregular and of the order of hundred nanoseconds. The average time between dropouts is much larger than the laser system characteristic time-scales. Semiconductor ring lasers are currently the focus of a rapidly thriving research activity due to their unique feature of directional bistability. They can be employed in systems for all-optical switching, gating, wavelength-conversion functions, and all-optical memories. Semiconductor ring lasers do not require cleaved facets or gratings for optical feedback and are thus particularly suited for monolithic integration. We experimentally and numerically address the issue of low-frequency fluctuations considering a semiconductor ring laser in a feedback configuration where only one directional mode is re-injected into the same directional mode, a so-called single self-feedback. We have observed that the system is very sensitive to the feedback strength and the injection current. In particular, the power dropouts are more regular when the pump current is increased and become less frequent when the feedback strength is increased. In addition, we find two different recovery processes after the power dropouts of the low-frequency fluctuations. The recovery can either occur via pulses or in a stepwise manner. Since low-frequency fluctuations are not specific to semiconductor ring lasers, we expect these recovery processes to appear also in VCSELs and edge-emitting lasers under similar feedback conditions. The numerical simulations also capture these different behaviors, where the representation in the phase space of

  14. Overreliance on auditory feedback may lead to sound/syllable repetitions: simulations of stuttering and fluency-inducing conditions with a neural model of speech production

    Science.gov (United States)

    Civier, Oren; Tasko, Stephen M.; Guenther, Frank H.

    2010-01-01

    This paper investigates the hypothesis that stuttering may result in part from impaired readout of feedforward control of speech, which forces persons who stutter (PWS) to produce speech with a motor strategy that is weighted too much toward auditory feedback control. Over-reliance on feedback control leads to production errors which, if they grow large enough, can cause the motor system to “reset” and repeat the current syllable. This hypothesis is investigated using computer simulations of a “neurally impaired” version of the DIVA model, a neural network model of speech acquisition and production. The model’s outputs are compared to published acoustic data from PWS’ fluent speech, and to combined acoustic and articulatory movement data collected from the dysfluent speech of one PWS. The simulations mimic the errors observed in the PWS subject’s speech, as well as the repairs of these errors. Additional simulations were able to account for enhancements of fluency gained by slowed/prolonged speech and masking noise. Together these results support the hypothesis that many dysfluencies in stuttering are due to a bias away from feedforward control and toward feedback control. PMID:20831971

  15. Robust Output Feedback Control for Uncertain Discrete Systems with Time Delays%不确定时滞离散系统的鲁棒输出反馈控制

    Institute of Scientific and Technical Information of China (English)

    刘碧玉; 桂卫华

    2005-01-01

    Based on design of an observer, the issue of dynamic output feedback control is studied for uncertain discrete systems with delays. A comparison theorem is given for nonlinear uncertain discrete systems with multiple time delays. Based on the comparison theorem with some inequalities,some delay-independent sufficient conditions for the robust stabilization of the systems are presented by means of output feedback.

  16. Output-feedback adaptive neural control for stochastic nonlinear time-varying delay systems with unknown control directions.

    Science.gov (United States)

    Li, Tieshan; Li, Zifu; Wang, Dan; Chen, C L Philip

    2015-06-01

    This paper presents an adaptive output-feedback neural network (NN) control scheme for a class of stochastic nonlinear time-varying delay systems with unknown control directions. To make the controller design feasible, the unknown control coefficients are grouped together and the original system is transformed into a new system using a linear state transformation technique. Then, the Nussbaum function technique is incorporated into the backstepping recursive design technique to solve the problem of unknown control directions. Furthermore, under the assumption that the time-varying delays exist in the system output, only one NN is employed to compensate for all unknown nonlinear terms depending on the delayed output. Moreover, by estimating the maximum of NN parameters instead of the parameters themselves, the NN parameters to be estimated are greatly decreased and the online learning time is also dramatically decreased. It is shown that all the signals of the closed-loop system are bounded in probability. The effectiveness of the proposed scheme is demonstrated by the simulation results.

  17. Estimating the Lyapunov spectrum of time delay feedback systems from scalar time series.

    Science.gov (United States)

    Hegger, R

    1999-08-01

    On the basis of a recently developed method for modeling time delay systems, we propose a procedure to estimate the spectrum of Lyapunov exponents from a scalar time series. It turns out that the spectrum is approximated very well and allows for good estimates of the Lyapunov dimension even if the sampling rate of the time series is so low that the infinite dimensional tangent space is spanned quite sparsely.

  18. Optimizing the dynamics of a two-cell DC-DC buck converter by time delayed feedback control

    Science.gov (United States)

    Feki, M.; El Aroudi, A.; Robert, B. G. M.; Martínez-Salamero, L.

    2011-11-01

    A study of the dynamical behavior of a two-cell DC-DC buck converter under a digital time delayed feedback control (TDFC) is presented. Various numerical simulations and dynamical aspects of this system are illustrated in the time domain and in the parameter space. Without TDFC, the system may present many undesirable behaviors such as sub-harmonics and chaotic oscillations. TDFC is able to widen the stability range of the system. Optimum values of parameters giving rise to fast response while maintaining stable periodic behavior are given in closed form. However, it is detected that in a certain region of the parameter space, the stabilized periodic orbit may coexist with a chaotic attractor. Boundary between basins of attraction are obtained by means of numerical simulations.

  19. Noise amplification by chaotic dynamics in a delayed feedback laser system and its application to nondeterministic random bit generation.

    Science.gov (United States)

    Sunada, Satoshi; Harayama, Takahisa; Davis, Peter; Tsuzuki, Ken; Arai, Ken-Ichi; Yoshimura, Kazuyuki; Uchida, Atsushi

    2012-12-01

    We present an experimental method for directly observing the amplification of microscopic intrinsic noise in a high-dimensional chaotic laser system, a laser with delayed feedback. In the experiment, the chaotic laser system is repeatedly switched from a stable lasing state to a chaotic state, and the time evolution of an ensemble of chaotic states starting from the same initial state is measured. It is experimentally demonstrated that intrinsic noises amplified by the chaotic dynamics are transformed into macroscopic fluctuating signals, and the probability density of the output light intensity actually converges to a natural invariant probability density in a strongly chaotic regime. Moreover, with the experimental method, we discuss the application of the chaotic laser systems to physical random bit generators. It is experimentally shown that the convergence to the invariant density plays an important role in nondeterministic random bit generation, which could be desirable for future ultimate secure communication systems.

  20. Congestion phenomenon analysis and delayed-feedback control in a modified coupled map traffic flow model containing the velocity difference

    Science.gov (United States)

    Fang, Ya-Ling; Shi, Zhong-Ke; Cao, Jin-Liang

    2015-06-01

    Based on the coupled map car-following model which was presented by Konishi et al. (1999), a modified coupled map car-following model is proposed. Specifically, the velocity difference between two successive vehicles is included in the model. The stability condition is given for the change of the speed of the preceding vehicle on the base of the control theory. We derive a condition under which the traffic jam never occurs in our model. Furthermore, in order to suppress traffic jams, we use static and dynamic version of decentralized delayed-feedback control for each vehicle, respectively, and provide a systematic procedure for designing the controller. In addition, the controller of each vehicle does not include any other vehicle information in real traffic flows.

  1. Auditory-motor learning influences auditory memory for music.

    Science.gov (United States)

    Brown, Rachel M; Palmer, Caroline

    2012-05-01

    In two experiments, we investigated how auditory-motor learning influences performers' memory for music. Skilled pianists learned novel melodies in four conditions: auditory only (listening), motor only (performing without sound), strongly coupled auditory-motor (normal performance), and weakly coupled auditory-motor (performing along with auditory recordings). Pianists' recognition of the learned melodies was better following auditory-only or auditory-motor (weakly coupled and strongly coupled) learning than following motor-only learning, and better following strongly coupled auditory-motor learning than following auditory-only learning. Auditory and motor imagery abilities modulated the learning effects: Pianists with high auditory imagery scores had better recognition following motor-only learning, suggesting that auditory imagery compensated for missing auditory feedback at the learning stage. Experiment 2 replicated the findings of Experiment 1 with melodies that contained greater variation in acoustic features. Melodies that were slower and less variable in tempo and intensity were remembered better following weakly coupled auditory-motor learning. These findings suggest that motor learning can aid performers' auditory recognition of music beyond auditory learning alone, and that motor learning is influenced by individual abilities in mental imagery and by variation in acoustic features.

  2. Integrating temporal difference methods and self-organizing neural networks for reinforcement learning with delayed evaluative feedback.

    Science.gov (United States)

    Tan, A H; Lu, N; Xiao, D

    2008-02-01

    This paper presents a neural architecture for learning category nodes encoding mappings across multimodal patterns involving sensory inputs, actions, and rewards. By integrating adaptive resonance theory (ART) and temporal difference (TD) methods, the proposed neural model, called TD fusion architecture for learning, cognition, and navigation (TD-FALCON), enables an autonomous agent to adapt and function in a dynamic environment with immediate as well as delayed evaluative feedback (reinforcement) signals. TD-FALCON learns the value functions of the state-action space estimated through on-policy and off-policy TD learning methods, specifically state-action-reward-state-action (SARSA) and Q-learning. The learned value functions are then used to determine the optimal actions based on an action selection policy. We have developed TD-FALCON systems using various TD learning strategies and compared their performance in terms of task completion, learning speed, as well as time and space efficiency. Experiments based on a minefield navigation task have shown that TD-FALCON systems are able to learn effectively with both immediate and delayed reinforcement and achieve a stable performance in a pace much faster than those of standard gradient-descent-based reinforcement learning systems.

  3. State-feedback ℋ∞ control for stochastic time-delay nonlinear systems with state and disturbance-dependent noise

    Science.gov (United States)

    Li, Huiping; Shi, Yang

    2012-10-01

    This article focuses on the state-feedback ℋ∞ control problem for the stochastic nonlinear systems with state and disturbance-dependent noise and time-varying state delays. Based on the maxmin optimisation approach, both the delay-independent and the delay-dependent Hamilton-Jacobi-inequalities (HJIs) are developed for synthesising the state-feedback ℋ∞ controller for a general type of stochastic nonlinear systems. It is shown that the resulting control system achieves stochastic stability in probability and the prescribed disturbance attenuation level. For a class of stochastic affine nonlinear systems, the delay-independent as well as delay-dependent matrix-valued inequalities are proposed; the resulting control system satisfies global asymptotic stability in the mean-square sense and the required disturbance attenuation level. By modelling the nonlinearities as uncertainties in corresponding stochastic time-delay systems, the sufficient conditions in terms of a linear matrix inequality (LMI) and a bilinear matrix inequality (BMI) are derived to facilitate the design of the state-feedback ℋ∞ controller. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed methods.

  4. Delayed mirror visual feedback presented using a novel mirror therapy system enhances cortical activation in healthy adults.

    Science.gov (United States)

    Lee, Hsin-Min; Li, Ping-Chia; Fan, Shih-Chen

    2015-07-11

    Mirror visual feedback (MVF) generated in mirror therapy (MT) with a physical mirror promotes the recovery of hemiparetic limbs in patients with stroke, but is limited in that it cannot provide an asymmetric mode for bimanual coordination training. Here, we developed a novel MT system that can manipulate the MVF to resolve this issue. The aims of this pilot study were to examine the feasibility of delayed MVF on MT and to establish its effects on cortical activation in order to understand how it can be used for clinical applications in the future. Three conditions (no MVF, MVF, and 2-s delayed MVF) presented via our digital MT system were evaluated for their time-course effects on cortical activity by event-related desynchronization (ERD) of mu rhythm electroencephalography (EEG) during button presses in 18 healthy adults. Phasic ERD areas, defined as the areas of the relative ERD curve that were below the reference level and within -2-0 s (P0), 0-2 s (P1), and 2-4 s (P2) of the button press, were used. The overall (P0 to P2) and phasic ERD areas were higher when MVF was provided compared to when MVF was not provided for all EEG channels (C3, Cz, and C4). Phasic ERD areas in the P2 phase only increased during the delayed-MVF condition. Significant enhancement of cortical activation in the mirror neuron system and an increase in attention to the unseen limb may play major roles in the response to MVF during MT. In comparison to the no MVF condition, the higher phasic ERD areas that were observed during the P1 phase in the delayed-MVF condition indicate that the image of the still hand may have enhanced the cortical activation that occurred in response to the button press. This study is the first to achieve delayed MVF for upper-limb MT. Our approach confirms previous findings regarding the effects of MVF on cortical activation and contributes additional evidence supporting the use of this method in the future for upper-limb motor training in patients with stroke.

  5. Oscillatory Gene Expression by the microRAN Mediating Delayed Negative Feedback Loop

    Institute of Scientific and Technical Information of China (English)

    ZHANG Feng-pan; LU Jin-rui; LIU Zhi-guang

    2013-01-01

    More and more experiments show that microRNAs can regulate gene expression by stimulating degradation of mRNA or repression of translation of mRNA.In this paper,we incorporate the microRNA into a previous mathematical model of gene expression through forming a microRNA-induced silencing complex(RISC).Our findings demonstrate the dynamical behavior of the constructed system.By Hopf theories,we derive the theoretical results of globally asymptotical stability and provide the sufficient conditions for the oscillation of the simple gene regulatory system,and by numerical simulation further demonstrate how the amplitudes against the change of delay in the gene regulatory network.

  6. Enhancing a slow and weak optomechanical nonlinearity with delayed quantum feedback to implement a CPHASE gate

    CERN Document Server

    Wang, Zhaoyou

    2016-01-01

    We show that the effective optical nonlinearity of a cavity optomechanical system can be used to implement quantum gates between propagating photons. By using quantum feedback, we can enhance a slow and small optical nonlinearity to generate a large nonlinear phase shift between two spatially separated temporal modes of a propagating electromagnetic field. This allows us to implement a CPHASE gate between the two modes. After presenting a semiclassical derivation of the operation of the gate, we verify the result by a full simulation of the state of the quantum field in the waveguide coupled to a cavity. To efficiently solve the Schr\\"odinger equation of the full system, we develop a matrix product state approach that keeps track of the entangled full quantum state of the coupled system. These simulations verify the operation of the gate in the weak coupling regime where the semiclassical approximation is valid. In addition, we observe a major reduction in gate fidelity as we approach the vacuum strong coupli...

  7. Social skills and developmental delay: importance in predicting the auditory and speech outcomes after cochlear implantation in children.

    Science.gov (United States)

    Chang, Young-Soo; Moon, Il Joon; Kim, Eun Yeon; Ahn, Jungmin; Chung, Won-Ho; Cho, Yang-Sun; Hong, Sung Hwa

    2015-02-01

    Preoperative evaluation of social interaction and global development levels using the Vineland Social Maturity Scale (VSMS) and Bayley Scales of Infant Development-2nd edition (BSID-II) may be beneficial in predicting the postoperative outcome in pediatric cochlear implant recipients. In particular, cautious preoperative counseling regarding the poor postoperative prognosis may be necessary in children with low social skills and developmental status. To determine the clinical benefit of preoperative evaluation of social interaction and global development levels using VSMS and BSID-II in predicting the postoperative outcome in pediatric cochlear implant recipients. A total of 65 deaf children who underwent cochlear implantation (CI) were included in this study. Age at the time of implantation ranged from 12 to 76 months. All of the children underwent a comprehensive preimplant psychological assessment by a clinical psychologist. The VSMS and BSID-II were used for evaluating social skills and a child's development preoperatively. A social quotient (SQ) was calculated by using the VSMS for each subject using the following formula: (social age/chronological age) × 100. The auditory perception and speech production abilities were evaluated using the Categories of Auditory Performance (CAP) scale and the Korean version of the Ling's stage (K-Ling), respectively, at 1 year after CI. The associations between the preoperative SQ/developmental levels and the postoperative auditory/speech outcomes were evaluated. The mean SQ was significantly decreased in the enrolled children (90.6 ± 26.1). The improvement in CAP score at 1 year after CI was correlated with preoperative SQ. The improvements in phonemic and phonologic levels of K-Ling were correlated with preoperative VSMS and BSID-II scores.

  8. 基于神经网络补偿的非线性时滞系统时滞正反馈控制%Time-delay Positive Feedback Control for Nonlinear Time-delay Systems with Neural Network Compensation

    Institute of Scientific and Technical Information of China (English)

    那靖; 任雪梅; 黄鸿

    2008-01-01

    A new adaptive time-delay positive feedback con-troller (ATPFC) is presented for a class of nonlinear time-delay systems. The proposed control scheme consists of a neural networks-based identification and a time-delay positive feedback controller. Two high-order neural networks (HONN) incorpo-rated with a special dynamic identification model are employed to identify the nonlinear system. Based on the identified model,local linearization compensation is used to deal with the un-known nonlinearity of the system. A time-delay-free inverse model of the linearized system and a desired reference model are utilized to constitute the feedback controller, which can lead the system output to track the trajectory of a reference model.Rigorous stability analysis for both the identification and the tracking error of the closcd-loop control system is provided by means of Lyapunov stability criterion. Simulation results are in-cluded to demonstrate the effectiveness of the proposed scheme.

  9. Quantifying lip-read-induced suppression and facilitation of the auditory N1 and P2 reveals peak enhancements and delays.

    Science.gov (United States)

    Baart, Martijn

    2016-09-01

    Lip-read speech suppresses and speeds up the auditory N1 and P2 peaks, but these effects are not always observed or reported. Here, the robustness of lip-read-induced N1/P2 suppression and facilitation in phonetically congruent audiovisual speech was assessed by analyzing peak values that were taken from published plots and individual data. To determine whether adhering to the additive model of AV integration (i.e., A+V ≠ AV, or AV-V ≠ A) is critical for correct characterization of lip-read-induced effects on the N1 and P2, auditory data was compared to AV and to AV-V. On average, the N1 and P2 were consistently suppressed and sped up by lip-read information, with no indication that AV integration effects were significantly modulated by whether or not V was subtracted from AV. To assess the possibility that variability in observed N1/P2 amplitudes and latencies may explain why N1/P2 suppression and facilitation are not always found, additional correlations between peak values and size of the AV integration effects were computed. These analyses showed that N1/P2 peak values correlated with the size of AV integration effects. However, it also became apparent that a portion of the AV integration effects was characterized by lip-read-induced peak enhancements and delays rather than suppressions and facilitations, which, for the individual data, seemed related to particularly small/early A-only peaks and large/late AV(-V) peaks.

  10. Auditory efferent feedback system deficits precede age-related hearing loss: contralateral suppression of otoacoustic emissions in mice.

    Science.gov (United States)

    Zhu, Xiaoxia; Vasilyeva, Olga N; Kim, Sunghee; Jacobson, Michael; Romney, Joshua; Waterman, Marjorie S; Tuttle, David; Frisina, Robert D

    2007-08-10

    The C57BL/6J mouse has been a useful model of presbycusis, as it displays an accelerated age-related peripheral hearing loss. The medial olivocochlear efferent feedback (MOC) system plays a role in suppressing cochlear outer hair cell (OHC) responses, particularly for background noise. Neurons of the MOC system are located in the superior olivary complex, particularly in the dorsomedial periolivary nucleus (DMPO) and in the ventral nucleus of the trapezoid body (VNTB). We previously discovered that the function of the MOC system declines with age prior to OHC degeneration, as measured by contralateral suppression (CS) of distortion product otoacoustic emissions (DPOAEs) in humans and CBA mice. The present study aimed to determine the time course of age changes in MOC function in C57s. DPOAE amplitudes and CS of DPOAEs were collected for C57s from 6 to 40 weeks of age. MOC responses were observed at 6 weeks but were gone at middle (15-30 kHz) and high (30-45 kHz) frequencies by 8 weeks. Quantitative stereological analyses of Nissl sections revealed smaller neurons in the DMPO and VNTB of young adult C57s compared with CBAs. These findings suggest that reduced neuron size may underlie part of the noteworthy rapid decline of the C57 efferent system. In conclusion, the C57 mouse has MOC function at 6 weeks, but it declines quickly, preceding the progression of peripheral age-related sensitivity deficits and hearing loss in this mouse strain.

  11. Existence and global asymptotic stability of positive periodic solutions of a Lotka-Volterra type competition systems with delays and feedback controls

    Directory of Open Access Journals (Sweden)

    Anh Tuan Trinh

    2013-11-01

    Full Text Available The existence of positive periodic solutions of a periodic Lotka-Volterra type competition system with delays and feedback controls is studied by applying the continuation theorem of coincidence degree theory. By contracting a suitable Liapunov functional, a set of sufficient conditions for the global asymptotic stability of the positive periodic solution of the system is given. A counterexample is given to show that the result on the existence of positive periodic solution in [4] is incorrect.

  12. Effects of quantum noise on the nonlinear dynamics of a semiconductor laser subject to two spectrally filtered, time-delayed optical feedbacks

    Science.gov (United States)

    Suelzer, Joseph S.; Prasad, Awadhesh; Ghosh, Rupamanjari; Vemuri, Gautam

    2016-07-01

    We report on a theoretical and computational investigation of the complex dynamics that arise in a semiconductor laser that is subject to two external, time-delayed, filtered optical feedbacks with special attention to the effect of quantum noise. In particular, we focus on the dynamics of the instantaneous optical frequency (wavelength) and its behavior for a wide range of feedback strengths and filter parameters. In the case of two intermediate filter bandwidths, the most significant results are that in the presence of noise, the feedback strengths required for the onset of chaos in a period doubling route are higher than in the absence of noise. We find that the inclusion of noise changes the dominant frequency of the wavelength oscillations, and that certain attractors do not survive in the presence of noise for a range of filter parameters. The results are interpreted by use of a combination of phase portraits, rf spectra, and first return maps.

  13. Experimental demonstration of change of dynamical properties of a passively mode-locked semiconductor laser subject to dual optical feedback by dual full delay-range tuning.

    Science.gov (United States)

    Nikiforov, O; Jaurigue, L; Drzewietzki, L; Lüdge, K; Breuer, S

    2016-06-27

    In this contribution we experimentally demonstrate the change and improvement of dynamical properties of a passively mode-locked semiconductor laser subject to optical feedback from two external cavities by coupling the feedback pulses back into the gain segment. Hereby, we tune the full delay-phase of the pulse-to-pulse period of both external cavities separately and demonstrate the change of the repetition rate, timing jitter, multi-pulse formation and side-band suppression for the first time for such a dual feedback configuration. In addition, we thereby confirm modeling predictions by achieving both a good qualitative and quantitative agreement of experimental and simulated results. Our findings suggest a path towards the realization of side-band free all-optical photonic oscillators based on mode-locked lasers.

  14. Impact of Feedback Channel Delay over Joint User Scheduling Scheme and Separated Random User Scheduling Scheme in LTE-A System with Carrier Aggregation

    Directory of Open Access Journals (Sweden)

    Ahmed A. Ali

    2014-01-01

    Full Text Available In Long Term Evolution-Advanced (LTE-A, the signal quality in a wireless channel is estimated based on the channel quality measurements. The measurement results are used to select suitable modulation and coding scheme for each transmission, feedback, and processing delay, which can cause a mismatch between channel quality information (CQI and current channel state at the base station. However, prospect delays in the reception of such CQI may lead to a system performance degradation. This study analyzes the impact of CQI feedback delay on joint user scheduling (JUS scheme and separated random user scheduling (SRUS scheme in LTE-A system over carrier aggregation. The analysis will be compared with the system having delayed channel and perfect knowledge at different deployment scenario. We will study the throughput performance of both scheduling schemes with different deployment scenario, and then recommend the suitable deployment scenario to keep the desired QoS for a specific number of users. Results show that, in main beam directed at sector boundaries and diverse coverage, JUS scheme performs better than SRUS, which can justify the intensive use of user equipment power and extra control signaling overhead.

  15. The effect of force feedback delay on stiffness perception and grip force modulation during tool-mediated interaction with elastic force fields.

    Science.gov (United States)

    Leib, Raz; Karniel, Amir; Nisky, Ilana

    2015-05-01

    During interaction with objects, we form an internal representation of their mechanical properties. This representation is used for perception and for guiding actions, such as in precision grip, where grip force is modulated with the predicted load forces. In this study, we explored the relationship between grip force adjustment and perception of stiffness during interaction with linear elastic force fields. In a forced-choice paradigm, participants probed pairs of virtual force fields while grasping a force sensor that was attached to a haptic device. For each pair, they were asked which field had higher level of stiffness. In half of the pairs, the force feedback of one of the fields was delayed. Participants underestimated the stiffness of the delayed field relatively to the nondelayed, but their grip force characteristics were similar in both conditions. We analyzed the magnitude of the grip force and the lag between the grip force and the load force in the exploratory probing movements within each trial. Right before answering which force field had higher level of stiffness, both magnitude and lag were similar between delayed and nondelayed force fields. These results suggest that an accurate internal representation of environment stiffness and time delay was used for adjusting the grip force. However, this representation did not help in eliminating the bias in stiffness perception. We argue that during performance of a perceptual task that is based on proprioceptive feedback, separate neural mechanisms are responsible for perception and action-related computations in the brain.

  16. The Application of Predictor Feedback in Designing a Preview Controller for Discrete-Time Systems with Input Delay

    Directory of Open Access Journals (Sweden)

    Fucheng Liao

    2016-01-01

    Full Text Available This paper presents a method for designing a type one servomechanism for a discrete-time linear system with input delay subject to a previewable desired output and a nonmeasurable constant disturbance. The tracking problem of a delay system is transformed into a regulation problem of a delay-free system via constructing an augmented error system and a variable substitution. A controller is obtained with delay compensation and preview compensation based on preview control theory and the predictor method. When the state vector is not directly measurable, a full-dimensional observer is offered. The effectiveness of the design method is demonstrated by numerical simulations.

  17. State Feedback Stabilzation for a Class of Time-delay Nonlinear Systems%一类非线性时滞系统的状态反馈镇定

    Institute of Scientific and Technical Information of China (English)

    张宪福; 程兆林

    2005-01-01

    The problem of global stabilization by state feedback for a class of time-delay nonlinear system is considered. By constructing the appropriate Lyapunov-Krasovskii functionals (LKF) and using the backstepping design, a linear state feedback controller making the closed-loop system globally asymptotically stable is constructed.

  18. Effect of State Feedback Coupling and System Delays on the Transient Performance of Stand-Alone VSI with LC Output Filter

    DEFF Research Database (Denmark)

    Federico, de Bosio; de Sousa Ribeiro, Luiz Antonio; Freijedo Fernandez, Francisco Daniel

    2016-01-01

    provided. A proportional resonant voltage controller is designed according to Nyquist criterion taking into account application requirements. For this purpose, a mathematical expression based on root locus analysis is proposed to find the minimum value of the fundamental resonant gain. Experimental tests...... on the state feedback decoupling path in order to compensate for system delays. Practical implementation issues are discussed with reference to both the decoupling techniques. A design methodology for the voltage loop, that considers the closed loop transfer functions developed for the inner loop, is also...... performed in accordance to UPS standards verify the theoretical analysis....

  19. 非相称多时奇异系统的有记忆状态反馈控制%Memory State Feedback Control for Singular Systems with Multiple Internal Incommensurate Constant Point Delays

    Institute of Scientific and Technical Information of China (English)

    蒋朝辉; 桂卫华; 谢永芳; 阳春华

    2009-01-01

    In this paper, the problem of delay-dependent stabilization for singular linear continuous-time systems with multiple internal incommensurate constant point delays (SLCS-MIID) is investigated. The condition when a singular system subject to point delays is regular independent of time delays is given and it can be easily tested with numerical or algebraic methods. Based on the Lyapunov-Krasovskii functional approach and the descriptor integral-inequality lemma, a sufficient condition for delay-dependent stability is obtained. The main idea is to design multiple memory state feedback control laws such that the resulting closed-loop system is regular independently of time delays, impulse free, and asymptotically stable via solving some strict linear matrix inequalities (LMIs) problem. An explicit expression for the desired memory state feedback control law is also given. Finally, a numerical example illustrates effectiveness and availability for the proposed method.

  20. 一个正反馈时滞微分方程的Hopf分支%Hopf Bifurcation of a Positive Feedback Delay Differential Equation

    Institute of Scientific and Technical Information of China (English)

    陈玉明; 黄立宏

    2003-01-01

    Under some minor technical hypotheses, for each τ larger than a certain τs > 0, Krisztin, Walther and Wu showed the existence of a periodic orbit for the positive feedback delay differential equation x(t) = -τμx(t) + τf(x(t - 1)), where τ and μ are positive constants and f: R → R satisfies f(0) = 0 and f′> 0.Combining this with a unique result of Krisztin and Walther, we know that this periodic orbit is the one branched out from 0 through Hopf bifurcation. Using the normal form theory for delay differential equations, we show the same result under the condition that f ∈ C3(R, R) is such that f"(0) = 0 and f′"(0) < 0, which is weaker than those of Krisztin and Walther.

  1. Finite-time H∞ control for discrete-time switched singular time-delay systems subject to actuator saturation via static output feedback

    Science.gov (United States)

    Ma, Yuechao; Fu, Lei

    2016-10-01

    This study employs the multiple Lyapunov-like function method and the average dwell-time concept of switching signal to investigate the finite-time H∞ static output-feedback (SOF) control problem for a class of discrete-time switched singular time-delay systems subject to actuator saturation. First, sufficient conditions are presented to guarantee the discrete-time switched singular time-delay system regular, causal and finite-time boundedness. Meanwhile, sufficient conditions are presented to ensure the H∞ disturbance attenuation level, and the design method of H∞ SOF controller is developed by solving matrix inequalities optimisation problem without any decompositions of system matrices and equivalent transformation. Finally, the effectiveness and merit of the theoretical results are shown through some numerical examples and several vivid illustrations.

  2. Adaptive Fuzzy Output-Feedback Method Applied to Fin Control for Time-Delay Ship Roll Stabilization

    Directory of Open Access Journals (Sweden)

    Rui Bai

    2014-01-01

    Full Text Available The ship roll stabilization by fin control system is considered in this paper. Assuming that angular velocity in roll cannot be measured, an adaptive fuzzy output-feedback control is investigated. The fuzzy logic system is used to approximate the uncertain term of the controlled system, and a fuzzy state observer is designed to estimate the unmeasured states. By utilizing the fuzzy state observer and combining the adaptive backstepping technique with adaptive fuzzy control design, an observer-based adaptive fuzzy output-feedback control approach is developed. It is proved that the proposed control approach can guarantee that all the signals in the closed-loop system are semiglobally uniformly ultimately bounded (SGUUB, and the control strategy is effective to decrease the roll motion. Simulation results are included to illustrate the effectiveness of the proposed approach.

  3. The sensitivity of Turing self-organization to biological feedback delays: 2D models of fish pigmentation

    KAUST Repository

    Gaffney, E. A.

    2013-10-01

    © The authors 2013. Turing morphogen models have been extensively explored in the context of large-scale self-organization in multicellular biological systems. However, reconciling the detailed biology of morphogen dynamics, while accounting for time delays associated with gene expression, reveals aberrant behaviours that are not consistent with early developmental self-organization, especially the requirement for exquisite temporal control. Attempts to reconcile the interpretation of Turing\\'s ideas with an increasing understanding of the mechanisms driving zebrafish pigmentation suggests that one should reconsider Turing\\'s model in terms of pigment cells rather than morphogens (Nakamasu et al., 2009, PNAS, 106, 8429-8434; Yamaguchi et al., 2007, PNAS, 104, 4790-4793). Here the dynamics of pigment cells is subject to response delays implicit in the cell cycle and apoptosis. Hence we explore simulations of fish skin patterning, focussing on the dynamical influence of gene expression delays in morphogen-based Turing models and response delays for cell-based Turing models. We find that reconciling the mechanisms driving the behaviour of Turing systems with observations of fish skin patterning remains a fundamental challenge.

  4. The sensitivity of Turing self-organization to biological feedback delays: 2D models of fish pigmentation.

    Science.gov (United States)

    Gaffney, E A; Lee, S Seirin

    2015-03-01

    Turing morphogen models have been extensively explored in the context of large-scale self-organization in multicellular biological systems. However, reconciling the detailed biology of morphogen dynamics, while accounting for time delays associated with gene expression, reveals aberrant behaviours that are not consistent with early developmental self-organization, especially the requirement for exquisite temporal control. Attempts to reconcile the interpretation of Turing's ideas with an increasing understanding of the mechanisms driving zebrafish pigmentation suggests that one should reconsider Turing's model in terms of pigment cells rather than morphogens (Nakamasu et al., 2009, PNAS, 106: , 8429-8434; Yamaguchi et al., 2007, PNAS, 104: , 4790-4793). Here the dynamics of pigment cells is subject to response delays implicit in the cell cycle and apoptosis. Hence we explore simulations of fish skin patterning, focussing on the dynamical influence of gene expression delays in morphogen-based Turing models and response delays for cell-based Turing models. We find that reconciling the mechanisms driving the behaviour of Turing systems with observations of fish skin patterning remains a fundamental challenge. © The Authors 2013. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  5. 分数阶时滞反馈对Duffng振子动力学特性的影响∗%Dynamical analysis of Duffng oscillator with fractional-order feedback with time delay

    Institute of Scientific and Technical Information of China (English)

    温少芳; 申永军; 杨绍普

    2016-01-01

    With increasingly strict requirements for control speed and system performance, the unavoidable time delay becomes a serious problem. Fractional-order feedback is constantly adopted in control engineering due to its advantages, such as robustness, strong de-noising ability and better control performance. In this paper, the dynamical characteristics of an autonomous Duffng oscillator under fractional-order feedback coupling with time delay are investigated. At first, the first-order approximate analytical solution is obtained by the averaging method. The equivalent stiffness and equivalent damping coeffcients are defined by the feedback coeffcient, fractional order and time delay. It is found that the fractional-order feedback coupling with time delay has the functions of both delayed velocity feedback and delayed displacement feedback simultaneously. Then, the comparison between the analytical solution and the numerical one verifies the correctness and satisfactory precision of the approximately analytical solution under three parameter conditions respectively. The effects of the feedback coeffcient, fractional order and nonlinear stiffness coeffcient on the complex dynamical behaviors are analyzed, including the locations of bifurcation points, the stabilities of the periodic solutions, the existence ranges of the periodic solutions, the stability of zero solution and the stability switch times. It is found that the increase of fractional order could make the delay-amplitude curves of periodic solutions shift rightwards, but the stabilities of the periodic solutions and the stability switch times of zero solution cannot be changed. The decrease of the feedback coeffcient makes the amplitudes and ranges of the periodic solutions become larger, and induces the stability switch times of zero solution to decrease, but the stabilities of the periodic solutions keep unchanged. The sign of the nonlinear stiffness coeffcient determines the stabilities and the bending

  6. Global stabilization of memristor-based fractional-order neural networks with delay via output-feedback control

    Science.gov (United States)

    Chen, Jiyang; Li, Chuandong; Huang, Tingwen; Yang, Xujun

    2017-02-01

    In this paper, the memristor-based fractional-order neural networks (MFNN) with delay and with two types of stabilizing control are described in detail. Based on the Lyapunov direct method, the theories of set-value maps, differential inclusions and comparison principle, some sufficient conditions and assumptions for global stabilization of this neural network model are established. Finally, two numerical examples are presented to demonstrate the effectiveness and practicability of the obtained results.

  7. Robustness with Respect to Small Delays for Exponential Stability of Pritchard-Salamon Systems with Admissible State Feedback%具容许状态反馈Pritchard-Salamon系统的小时滞鲁棒稳定性

    Institute of Scientific and Technical Information of China (English)

    刘艳; 蒋卫生; 黄发伦

    2004-01-01

    It has been observed that for many stable feedback control systems, the introduction of arbitrarily small delays into the loop causes instability. Therefore, robustness of stablility with respect to small delays is of great importance. The authors study the robustness with respect to small delays for exponential stability of Pritchard-Salamon systems with admissible state feedback,i.e. the exponential stability of the following systems are equivalent:(x(t)=S(t)x0+∫t0S(t-s)ds)(u(t)=Fx(t),x0∈V,t≥0)(x(t)=S(t)x0+∫t0S(t-s)BFx(s-r)ds)(u(t)=Fx(t-r),x0∈V,t≥0)and obtain a mumber of necessary and sufficient conditions,particularly,frepuency domain characterization for robustness with respect to small delays for exponential stability.

  8. Adaptive Neural Tracking Control for Unknown Output Feedback Nonlinear Time-delay Systems%未知输出反馈非线性时滞系统自适应神经网络跟踪控制

    Institute of Scientific and Technical Information of China (English)

    陈为胜; 李俊民

    2005-01-01

    An adaptive output feedback neural network tracking controller is designed for a class of unknown output feedback nonlinear time-delay systems by using backstepping technique. Neural networks are used to approximate unknown time-delay functions. Delay-dependent filters are introduced for state estimation. The domination method is used to deal with the smooth time-delay basis functions. The adaptive bounding technique is employed to estimate the upper bound of the neural network reconstruction error. Based on Lyapunov-Krasoviskii functional, the semi-global uniform ultimate boundedness (SGUUB) of all the signals in the closed-loop system is proved. The arbitrary output tracking accuracy is achieved by tuning the design parameters and the neural node number.The feasibility is investigated by an illustrative simulationexample.

  9. Output Feedback Adaptive Dynamic Surface Control of Permanent Magnet Synchronous Motor with Uncertain Time Delays via RBFNN

    Directory of Open Access Journals (Sweden)

    Shaohua Luo

    2014-01-01

    Full Text Available This paper focuses on an adaptive dynamic surface control based on the Radial Basis Function Neural Network for a fourth-order permanent magnet synchronous motor system wherein the unknown parameters, disturbances, chaos, and uncertain time delays are presented. Neural Network systems are used to approximate the nonlinearities and an adaptive law is employed to estimate accurate parameters. Then, a simple and effective controller has been obtained by introducing dynamic surface control technique on the basis of first-order filters. Asymptotically tracking stability in the sense of uniformly ultimate boundedness is achieved in a short time. Finally, the performance of the proposed control has been illustrated through simulation results.

  10. Fuzzy [Formula: see text] output-feedback control for the discrete-time system with channel fadings, sector nonlinearities, and randomly occurring interval delays and nonlinearities.

    Science.gov (United States)

    Fan, Xiaozheng; Wang, Yan; Hu, Manfeng

    2016-01-01

    In this paper, the fuzzy [Formula: see text] output-feedback control problem is investigated for a class of discrete-time T-S fuzzy systems with channel fadings, sector nonlinearities, randomly occurring interval delays (ROIDs) and randomly occurring nonlinearities (RONs). A series of variables of the randomly occurring phenomena obeying the Bernoulli distribution is used to govern ROIDs and RONs. Meanwhile, the measurement outputs are subject to the sector nonlinearities (i.e. the sensor saturations) and we assume the system output is [Formula: see text], [Formula: see text]. The Lth-order Rice model is utilized to describe the phenomenon of channel fadings by setting different values of the channel coefficients. The aim of this work is to deal with the problem of designing a full-order dynamic fuzzy [Formula: see text] output-feedback controller such that the fuzzy closed-loop system is exponentially mean-square stable and the [Formula: see text] performance constraint is satisfied, by means of a combination of Lyapunov stability theory and stochastic analysis along with LMI methods. The proposed fuzzy controller parameters are derived by solving a convex optimization problem via the semidefinite programming technique. Finally, a numerical simulation is given to illustrate the feasibility and effectiveness of the proposed design technique.

  11. Feedback stabilization of discrete-time quantum systems subject to non-demolition measurements with imperfections and delays

    CERN Document Server

    Amini, Hadis; Dotsenko, Igor; Sayrin, Clement; Mirrahimi, Mazyar; Rouchon, Pierre

    2012-01-01

    The mathematical methods underlying a recent quantum feedback experiment stabilizing photon-number states is developed. It considers a controlled system whose quantum state, a finite dimensional density operator, is governed by a discrete-time nonlinear Markov process. In open-loop, the measurements are assumed to be quantum non-demolition (QND) measurements. This Markov process admits a set of stationary pure states associated to an orthonormal basis. These stationary states provide martingales crucial to prove the open-loop stability: under simple assumptions, almost all trajectories converge to one of these stationary states; the probability to converge to a stationary state is given by its overlap with the initial quantum state. From these open-loop martingales, we construct a supermartingale whose parameters are given by inverting a Metzler matrix characterizing the impact of the control input on the Kraus operators defining the Markov process. This supermartingale measures the "distance" between the cur...

  12. Auditory agnosia.

    Science.gov (United States)

    Slevc, L Robert; Shell, Alison R

    2015-01-01

    Auditory agnosia refers to impairments in sound perception and identification despite intact hearing, cognitive functioning, and language abilities (reading, writing, and speaking). Auditory agnosia can be general, affecting all types of sound perception, or can be (relatively) specific to a particular domain. Verbal auditory agnosia (also known as (pure) word deafness) refers to deficits specific to speech processing, environmental sound agnosia refers to difficulties confined to non-speech environmental sounds, and amusia refers to deficits confined to music. These deficits can be apperceptive, affecting basic perceptual processes, or associative, affecting the relation of a perceived auditory object to its meaning. This chapter discusses what is known about the behavioral symptoms and lesion correlates of these different types of auditory agnosia (focusing especially on verbal auditory agnosia), evidence for the role of a rapid temporal processing deficit in some aspects of auditory agnosia, and the few attempts to treat the perceptual deficits associated with auditory agnosia. A clear picture of auditory agnosia has been slow to emerge, hampered by the considerable heterogeneity in behavioral deficits, associated brain damage, and variable assessments across cases. Despite this lack of clarity, these striking deficits in complex sound processing continue to inform our understanding of auditory perception and cognition. © 2015 Elsevier B.V. All rights reserved.

  13. Modulations of the auditory M100 in an imitation task

    NARCIS (Netherlands)

    Franken, M.K.M.; Hagoort, P.; Acheson, D.J.

    2015-01-01

    Models of speech production explain event-related suppression of the auditory cortical response as reflecting a comparison between auditory predictions and feedback. The present MEG study was designed to test two predictions from this framework: (1) whether the reduced auditory response varies as a

  14. Speech-induced suppression of evoked auditory fields in children who stutter.

    Science.gov (United States)

    Beal, Deryk S; Quraan, Maher A; Cheyne, Douglas O; Taylor, Margot J; Gracco, Vincent L; De Nil, Luc F

    2011-02-14

    Auditory responses to speech sounds that are self-initiated are suppressed compared to responses to the same speech sounds during passive listening. This phenomenon is referred to as speech-induced suppression, a potentially important feedback-mediated speech-motor control process. In an earlier study, we found that both adults who do and do not stutter demonstrated a reduced amplitude of the auditory M50 and M100 responses to speech during active production relative to passive listening. It is unknown if auditory responses to self-initiated speech-motor acts are suppressed in children or if the phenomenon differs between children who do and do not stutter. As stuttering is a developmental speech disorder, examining speech-induced suppression in children may identify possible neural differences underlying stuttering close to its time of onset. We used magnetoencephalography to determine the presence of speech-induced suppression in children and to characterize the properties of speech-induced suppression in children who stutter. We examined the auditory M50 as this was the earliest robust response reproducible across our child participants and the most likely to reflect a motor-to-auditory relation. Both children who do and do not stutter demonstrated speech-induced suppression of the auditory M50. However, children who stutter had a delayed auditory M50 peak latency to vowel sounds compared to children who do not stutter indicating a possible deficiency in their ability to efficiently integrate auditory speech information for the purpose of establishing neural representations of speech sounds. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Bilateral duplication of the internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Weon, Young Cheol; Kim, Jae Hyoung; Choi, Sung Kyu [Seoul National University College of Medicine, Department of Radiology, Seoul National University Bundang Hospital, Seongnam-si (Korea); Koo, Ja-Won [Seoul National University College of Medicine, Department of Otolaryngology, Seoul National University Bundang Hospital, Seongnam-si (Korea)

    2007-10-15

    Duplication of the internal auditory canal is an extremely rare temporal bone anomaly that is believed to result from aplasia or hypoplasia of the vestibulocochlear nerve. We report bilateral duplication of the internal auditory canal in a 28-month-old boy with developmental delay and sensorineural hearing loss. (orig.)

  16. Auditory short-term memory in the primate auditory cortex.

    Science.gov (United States)

    Scott, Brian H; Mishkin, Mortimer

    2016-06-01

    Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory.

  17. Auditory hallucinations.

    Science.gov (United States)

    Blom, Jan Dirk

    2015-01-01

    Auditory hallucinations constitute a phenomenologically rich group of endogenously mediated percepts which are associated with psychiatric, neurologic, otologic, and other medical conditions, but which are also experienced by 10-15% of all healthy individuals in the general population. The group of phenomena is probably best known for its verbal auditory subtype, but it also includes musical hallucinations, echo of reading, exploding-head syndrome, and many other types. The subgroup of verbal auditory hallucinations has been studied extensively with the aid of neuroimaging techniques, and from those studies emerges an outline of a functional as well as a structural network of widely distributed brain areas involved in their mediation. The present chapter provides an overview of the various types of auditory hallucination described in the literature, summarizes our current knowledge of the auditory networks involved in their mediation, and draws on ideas from the philosophy of science and network science to reconceptualize the auditory hallucinatory experience, and point out directions for future research into its neurobiologic substrates. In addition, it provides an overview of known associations with various clinical conditions and of the existing evidence for pharmacologic and non-pharmacologic treatments.

  18. Pulse delay feedback control method for a class of game model in power market%电力市场中一类博弈模型的脉冲延迟反馈控制法

    Institute of Scientific and Technical Information of China (English)

    王国栋

    2014-01-01

    In view of the problem of chaos for a class of nonlinear financial model in power market,by adding pulse time delayed feedback control method,its stability was studied,the first form is the introduction of sys-tem variables on an investment of time delayed feedback control,and the second form is introduced into the system variables of the system with time delayed feedback control and numerical simulations were presented to verify the theoretical results with Matlab software. The results show that impulses and time-delayed feed-backs can control the stability of system effectively.%针对电力市场中一类非线性博弈模型的混沌问题,通过加入脉冲时间延迟反馈控制,对其稳定性进行研究。第一种形式是对一家投资商引入系统变量的时间延迟反馈控制法,第二种形式是对整个系统引入系统变量的时间延迟反馈控制,并利用Matlab软件对该系统进行数值模拟,验证该方法的有效性。结果表明:时间延迟反馈控制可以有效控制系统的稳定性。

  19. Emotional feedback for mobile devices

    CERN Document Server

    Seebode, Julia

    2015-01-01

    This book investigates the functional adequacy as well as the affective impression made by feedback messages on mobile devices. It presents an easily adoptable experimental setup to examine context effects on various feedback messages, and applies it to auditory, tactile and auditory-tactile feedback messages. This approach provides insights into the relationship between the affective impression and functional applicability of these messages as well as an understanding of the influence of unimodal components on the perception of multimodal feedback messages. The developed paradigm can also be extended to investigate other aspects of context and used to investigate feedback messages in modalities other than those presented. The book uses questionnaires implemented on a Smartphone, which can easily be adopted for field studies to broaden the scope even wider. Finally, the book offers guidelines for the design of system feedback.

  20. Auditory and motor imagery modulate learning in music performance.

    Science.gov (United States)

    Brown, Rachel M; Palmer, Caroline

    2013-01-01

    Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians' encoding (during Learning, as they practiced novel melodies), and retrieval (during Recall of those melodies). Pianists learned melodies by listening without performing (auditory learning) or performing without sound (motor learning); following Learning, pianists performed the melodies from memory with auditory feedback (Recall). During either Learning (Experiment 1) or Recall (Experiment 2), pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced) and temporal regularity (variability of quarter-note interonset intervals) were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists' pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2). Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1): Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2): Higher auditory imagery skill predicted greater temporal regularity during Recall in the presence of

  1. Impact on vibration error characteristics of FOG with feedback delay%反馈延迟对光纤陀螺振动误差特性的影响

    Institute of Scientific and Technical Information of China (English)

    潘雄; 张春生; 王夏霄; 王熙辰; 赵亚飞; 王定球

    2014-01-01

    Large disturbance is introduced into fiber optic gyroscope under vibration environment. And the error characteristics for FOG are severely affected with the ability of tracking disturbance as the existence of non-linear factors, which becomes more complicated as the result of the additional feedback delay. Therefore, it is important for solving vibration problem to analyze the feedback delay. Firstly, impacts on the closed-loop tracking ability and the stability against disturbance of FOG with different feedback delay were analyzed with the non-linear factors. Then, the non-linear element was considered based on the linear control model, and the outputs of FOG with different feedback delay were obtained and the tracking performance was analyzed by simulation as keeping the same stability margin. The simulation and final experiment show that the bias of FOG will be brought into a large offset under vibration with a poor tracking performance. Thus, it is important to solve the vibration problem of FOG by improving the closed-loop tracking ability with a small feedback delay.%振动环境导致光纤陀螺引入较大的扰动。由于非线性因素,陀螺跟踪扰动的能力严重影响着其误差特性,而反馈延迟的存在使得跟踪性能变得更加复杂。因此,分析反馈延迟对于解决陀螺振动问题极其重要。首先,分析了非线性因素作用时不同反馈延迟对陀螺闭环跟踪能力和扰动稳定性的影响;然后在线性控制模型的基础上加入陀螺非线性环节,保证稳定裕度不变,仿真分析了不同反馈延迟下陀螺的跟踪性能以及输出。仿真及实验结果表明,减小反馈延迟,提高系统的跟踪扰动能力,可以减小非线性误差,改善振动环境下陀螺的输出性能。

  2. Auditory N1 reveals planning and monitoring processes during music performance.

    Science.gov (United States)

    Mathias, Brian; Gehring, William J; Palmer, Caroline

    2017-02-01

    The current study investigated the relationship between planning processes and feedback monitoring during music performance, a complex task in which performers prepare upcoming events while monitoring their sensory outcomes. Theories of action planning in auditory-motor production tasks propose that the planning of future events co-occurs with the perception of auditory feedback. This study investigated the neural correlates of planning and feedback monitoring by manipulating the contents of auditory feedback during music performance. Pianists memorized and performed melodies at a cued tempo in a synchronization-continuation task while the EEG was recorded. During performance, auditory feedback associated with single melody tones was occasionally substituted with tones corresponding to future (next), present (current), or past (previous) melody tones. Only future-oriented altered feedback disrupted behavior: Future-oriented feedback caused pianists to slow down on the subsequent tone more than past-oriented feedback, and amplitudes of the auditory N1 potential elicited by the tone immediately following the altered feedback were larger for future-oriented than for past-oriented or noncontextual (unrelated) altered feedback; larger N1 amplitudes were associated with greater slowing following altered feedback in the future condition only. Feedback-related negativities were elicited in all altered feedback conditions. In sum, behavioral and neural evidence suggests that future-oriented feedback disrupts performance more than past-oriented feedback, consistent with planning theories that posit similarity-based interference between feedback and planning contents. Neural sensory processing of auditory feedback, reflected in the N1 ERP, may serve as a marker for temporal disruption caused by altered auditory feedback in auditory-motor production tasks.

  3. Auditory and motor imagery modulate learning in music performance

    Directory of Open Access Journals (Sweden)

    Rachel M. Brown

    2013-07-01

    Full Text Available Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians’ encoding (during Learning, as they practiced novel melodies, and retrieval (during Recall of those melodies. Pianists learned melodies by listening without performing (auditory learning or performing without sound (motor learning; following Learning, pianists performed the melodies from memory with auditory feedback (Recall. During either Learning (Experiment 1 or Recall (Experiment 2, pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced and temporal regularity (variability of quarter-note interonset intervals were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists’ pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2. Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1: Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2: Higher auditory imagery skill predicted greater temporal regularity during Recall in the

  4. Time-Delayed Velocity-Acceleration Feedback for Active Vibration Control of Cantilever Beam%基于速度-加速度时滞反馈的振动主动控制

    Institute of Scientific and Technical Information of China (English)

    安方; 陈卫东; 邵敏强

    2012-01-01

    The design problem of the time-delayed controller with the measured acceleration signal is presented, which is used to neutralize the effect of the group delay induced by the low-pass filter on active vibration control systems. By means of the reduction method and the state-derivative feedback strategy, a time-delayed velocity-acceleration feedback controller is proposed without the inclusion of the displacement signal, so that the accumulation errors caused by twice integration of the acceleration signal can be avoided. The developed time delayed feedback controller is examined by the computer simulation, with a special focusing on the control performance of a cantilever beam with the piezoelectric actuator and the acceleration sensor. Simulation results demonstrate that the controller can effectively reduce the free vibration response of the intelligent cantilever beam, and compared with the velocity-acceleration feedback controller, it has better control effects at different time delays.%在振动主动控制中,基于加速度测量信号,并考虑滤波器群时延引入的时滞,研究了一种时滞控制器设计方法.采用等维方法和状态导数反馈思想,提出一种速度-加速度时滞反馈控制器的设计方法.该控制器不含位移信号,可省去两次数值积分和去直流分量、趋势项这两个过程,并可避免由两次数值积分带来的累积误差.以粘帖有压电陶瓷和加速度传感器的智能梁为控制对象,采用该控制器控制其自由振动,并与速度-加速度反馈控制效果进行比较.仿真结果表明,当采用速度-加速度反馈直接控制时滞系统时,若时滞超出其稳定区间,该方法失效,而速度-加速度时滞反馈控制方法则具有良好的控制效果.

  5. From ear to hand: the role of the auditory-motor loop in pointing to an auditory source

    Science.gov (United States)

    Boyer, Eric O.; Babayan, Bénédicte M.; Bevilacqua, Frédéric; Noisternig, Markus; Warusfel, Olivier; Roby-Brami, Agnes; Hanneton, Sylvain; Viaud-Delmon, Isabelle

    2013-01-01

    Studies of the nature of the neural mechanisms involved in goal-directed movements tend to concentrate on the role of vision. We present here an attempt to address the mechanisms whereby an auditory input is transformed into a motor command. The spatial and temporal organization of hand movements were studied in normal human subjects as they pointed toward unseen auditory targets located in a horizontal plane in front of them. Positions and movements of the hand were measured by a six infrared camera tracking system. In one condition, we assessed the role of auditory information about target position in correcting the trajectory of the hand. To accomplish this, the duration of the target presentation was varied. In another condition, subjects received continuous auditory feedback of their hand movement while pointing to the auditory targets. Online auditory control of the direction of pointing movements was assessed by evaluating how subjects reacted to shifts in heard hand position. Localization errors were exacerbated by short duration of target presentation but not modified by auditory feedback of hand position. Long duration of target presentation gave rise to a higher level of accuracy and was accompanied by early automatic head orienting movements consistently related to target direction. These results highlight the efficiency of auditory feedback processing in online motor control and suggest that the auditory system takes advantages of dynamic changes of the acoustic cues due to changes in head orientation in order to process online motor control. How to design an informative acoustic feedback needs to be carefully studied to demonstrate that auditory feedback of the hand could assist the monitoring of movements directed at objects in auditory space. PMID:23626532

  6. From ear to hand: the role of the auditory-motor loop in pointing to an auditory source

    Directory of Open Access Journals (Sweden)

    Eric Olivier Boyer

    2013-04-01

    Full Text Available Studies of the nature of the neural mechanisms involved in goal-directed movements tend to concentrate on the role of vision. We present here an attempt to address the mechanisms whereby an auditory input is transformed into a motor command. The spatial and temporal organization of hand movements were studied in normal human subjects as they pointed towards unseen auditory targets located in a horizontal plane in front of them. Positions and movements of the hand were measured by a six infrared camera tracking system. In one condition, we assessed the role of auditory information about target position in correcting the trajectory of the hand. To accomplish this, the duration of the target presentation was varied. In another condition, subjects received continuous auditory feedback of their hand movement while pointing to the auditory targets. Online auditory control of the direction of pointing movements was assessed by evaluating how subjects reacted to shifts in heard hand position. Localization errors were exacerbated by short duration of target presentation but not modified by auditory feedback of hand position. Long duration of target presentation gave rise to a higher level of accuracy and was accompanied by early automatic head orienting movements consistently related to target direction. These results highlight the efficiency of auditory feedback processing in online motor control and suggest that the auditory system takes advantages of dynamic changes of the acoustic cues due to changes in head orientation in order to process online motor control. How to design an informative acoustic feedback needs to be carefully studied to demonstrate that auditory feedback of the hand could assist the monitoring of movements directed at objects in auditory space.

  7. Auditory-perceptual learning improves speech motor adaptation in children.

    Science.gov (United States)

    Shiller, Douglas M; Rochon, Marie-Lyne

    2014-08-01

    Auditory feedback plays an important role in children's speech development by providing the child with information about speech outcomes that is used to learn and fine-tune speech motor plans. The use of auditory feedback in speech motor learning has been extensively studied in adults by examining oral motor responses to manipulations of auditory feedback during speech production. Children are also capable of adapting speech motor patterns to perceived changes in auditory feedback; however, it is not known whether their capacity for motor learning is limited by immature auditory-perceptual abilities. Here, the link between speech perceptual ability and the capacity for motor learning was explored in two groups of 5- to 7-year-old children who underwent a period of auditory perceptual training followed by tests of speech motor adaptation to altered auditory feedback. One group received perceptual training on a speech acoustic property relevant to the motor task while a control group received perceptual training on an irrelevant speech contrast. Learned perceptual improvements led to an enhancement in speech motor adaptation (proportional to the perceptual change) only for the experimental group. The results indicate that children's ability to perceive relevant speech acoustic properties has a direct influence on their capacity for sensory-based speech motor adaptation.

  8. Time-delay feedback control and stability analysis of piezoelectric-coupling cantilever beam%压电耦合悬臂梁的时滞反馈控制及稳定性分析

    Institute of Scientific and Technical Information of China (English)

    冯志宏; 霍睿

    2011-01-01

    Based on the closed-up control strategy of acceleration time-delay feedback, a dynamics model of piezoelectric-coupling flexible cantilever beam was set up.The stability conditions and dynamic characteristics of the system were achieved via conducting the modal analysis and free vibration trivial solutions analysis.The effects of piezoelectric coupling and time delay were considered and a specific example was presented to proof the previous results.The example shows that ignoring time-delay unreasonably may cause the system to respond divergently, while a reasonable amount of time-delay can improve the efficiency of vibration control.%基于加速度-时滞闭环反馈控制策略,建立压电耦合柔性悬臂梁的动力学模型,通过运用模态分析和对系统自由振动的平凡解的分析,建立了在考虑压电耦合作用和反馈时滞条件下的系统稳定性条件和分析方法,并给出了具体算例;进一步的算例分析表明,时滞的不合理忽略有可能导致系统响应发散,而合理的时滞量也可用以提高振动控制的效率.

  9. [Auditory fatigue].

    Science.gov (United States)

    Sanjuán Juaristi, Julio; Sanjuán Martínez-Conde, Mar

    2015-01-01

    Given the relevance of possible hearing losses due to sound overloads and the short list of references of objective procedures for their study, we provide a technique that gives precise data about the audiometric profile and recruitment factor. Our objectives were to determine peripheral fatigue, through the cochlear microphonic response to sound pressure overload stimuli, as well as to measure recovery time, establishing parameters for differentiation with regard to current psychoacoustic and clinical studies. We used specific instruments for the study of cochlear microphonic response, plus a function generator that provided us with stimuli of different intensities and harmonic components. In Wistar rats, we first measured the normal microphonic response and then the effect of auditory fatigue on it. Using a 60dB pure tone acoustic stimulation, we obtained a microphonic response at 20dB. We then caused fatigue with 100dB of the same frequency, reaching a loss of approximately 11dB after 15minutes; after that, the deterioration slowed and did not exceed 15dB. By means of complex random tone maskers or white noise, no fatigue was caused to the sensory receptors, not even at levels of 100dB and over an hour of overstimulation. No fatigue was observed in terms of sensory receptors. Deterioration of peripheral perception through intense overstimulation may be due to biochemical changes of desensitisation due to exhaustion. Auditory fatigue in subjective clinical trials presumably affects supracochlear sections. The auditory fatigue tests found are not in line with those obtained subjectively in clinical and psychoacoustic trials. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

  10. Auditory feedback influences perceived driving speeds.

    Science.gov (United States)

    Horswill, Mark S; Plooy, Annaliese M

    2008-01-01

    Reducing the level of internal noise is seen as a goal when designing modern cars. One danger of such a philosophy is that one is systematically attempting to alter one of the cues that can be used by drivers to estimate speed and this could bias speed judgments and driving behaviour. Seven participants were presented with pairs of video-based driving scenes and asked to judge whether the second scene appeared faster or slower than the first (2-alternative forced-choice task using the method of constant stimuli). They either heard in-car noise at the level it occurred in the real world or reduced in volume by 5 dB. The reduction in noise led to participants judging speeds to be significantly slower and this effect was evident for all participants. This finding indicates that, when in-car noise is attenuated, drivers are likely to underestimate their speed, potentially encouraging them to drive faster and placing them at greater risk of crashing.

  11. Audio Feedback -- Better Feedback?

    Science.gov (United States)

    Voelkel, Susanne; Mello, Luciane V.

    2014-01-01

    National Student Survey (NSS) results show that many students are dissatisfied with the amount and quality of feedback they get for their work. This study reports on two case studies in which we tried to address these issues by introducing audio feedback to one undergraduate (UG) and one postgraduate (PG) class, respectively. In case study one…

  12. How Do Batters Use Visual, Auditory, and Tactile Information about the Success of a Baseball Swing?

    Science.gov (United States)

    Gray, Rob

    2009-01-01

    Bat/ball contact produces visual (the ball leaving the bat), auditory (the "crack" of the bat), and tactile (bat vibration) feedback about the success of the swing. We used a batting simulation to investigate how college baseball players use visual, tactile, and auditory feedback. In Experiment 1, swing accuracy (i.e., the lateral separation…

  13. How Do Batters Use Visual, Auditory, and Tactile Information about the Success of a Baseball Swing?

    Science.gov (United States)

    Gray, Rob

    2009-01-01

    Bat/ball contact produces visual (the ball leaving the bat), auditory (the "crack" of the bat), and tactile (bat vibration) feedback about the success of the swing. We used a batting simulation to investigate how college baseball players use visual, tactile, and auditory feedback. In Experiment 1, swing accuracy (i.e., the lateral separation…

  14. 基于扩张状态观测器的航天器时延状态反馈控制%Spacecraft time-delay state feedback control based on extended state observer

    Institute of Scientific and Technical Information of China (English)

    史小平; 毕显婷; 杨婧

    2016-01-01

    研究了刚性航天器的时延姿态稳定控制问题。首先建立了基于修正罗德里格斯参数(modified ro-drigues parameters,MRPs)的航天器非线性状态模型,具有确定上界的时延项在状态反馈控制律中体现。通过构造Lyapunov-Krasovskii 泛函进行稳定性分析,由此得到保证系统渐近稳定的线性矩阵不等式,依此设计状态反馈控制系数矩阵。考虑到航天器三轴间的耦合非线性项,利用扩张状态观测器(extended state observer,ESO)方法,设计了二阶非线性扩张状态观测器,以获得航天器系统内部状态向量并用于状态反馈控制律。为便于工程实际应用,仿真中将 MRPs 响应输出转换为欧拉角响应,仿真结果表明,本文所设计的控制系统能保证航天器三轴姿态稳定。%This paper researches the problem of rigid body spacecraft time-delay attitude stabilization. Firstly,the spacecraft nonlinear state model based on modified rodrigues parameters (MRPs)is established,the time delay term with certain upper boundary is modeled in state feedback control law.Lyapunov-Krasovskii functional is constructed for this nonlinear time-delay system to achieve asymptotic stabilization,linear matrix inequalities are accordingly obtained and the state feedback control coefficients matrixes are thereby computed with.Concerning the three-axis coupling nonlinear terms in spacecraft,the extended state observer (ESO) method is used to design a two rank nonlinear ESO,the spacecraft system internal state vector is therefore ac-quired and used in the aforementioned state feedback control law.For the convenience of engineering applica-tion,the MRPs state vector is converted to Euler angles in simulation.The simulation results show the efficient of the state feedback control law with three-axis attitude asymptotic stabilization achieved.

  15. Feedback Stabilization for a Class of Distributed Parameter Switched Systems with Time Delay%一类时滞分布参数切换系统的反馈镇定

    Institute of Scientific and Technical Information of China (English)

    董学平; 温锐; 刘红亮

    2011-01-01

    研究了一类具有时滞的分布参数切换系统反馈镇定问题.通过构造Lyapunov函数,利用Green公式获得了系统状态反馈镇定的充分条件.该条件用一组线性矩阵不等式表示,从而将分布参数切换系统状态反馈镇定问题转化为一组线性矩阵不等式的可行解问题,可借助Matlab中线性矩阵不等式工具箱求解.该方法获得的充分条件容易检验,因而易于应用.通过数值算例说明该方法的有效性.%Feedback stabilization for a class of distributed parameter switched systems (DPSS) with time-delay is studied. By constructing Lyapunov functions and employing the Green formula, several sufficient conditions of state feedback stabilization for a class of DPSS with constant time delay are derived. These conditions are described using a group of linear matrix inequalities (LMI). Thus design of state feedback controllers of DPSS is converted to a group of LMI. The controllers can be solved efficiently with the Matlab LMI toolbox. In addition, the proposed method has the advantage that the criteria can easily be checked and applied. A numerical example is given to illustrate validity of the design method.

  16. 利用时间延迟状态反馈实现异步电机的混沌合成%Chaos Synthesis of Asynchronous Motor by Time-Delayed State Feedback

    Institute of Scientific and Technical Information of China (English)

    李卫东; 唐斌

    2012-01-01

    为了在三相交流异步电机的运行过程中实现混沌合成,采用非线性系统的微分几何理论和时间延迟反馈控制的方法,设计了混沌合成控制器.该控制器通过对三相交流异步电机模型的简化分析,并利用非线性控制理论的状态反馈精确线性化方法来设计.应该此控制器即可得到异步电机运行时的混沌合成.应用Matlab软件中Simulink 工具进行仿真分析,仿真结果说明利用时间延迟状态反馈设计的控制器实现异步电机的混沌合成是完全合理可行的,运行结果也是满足要求的.%The chaos synthesis controller is designed using the method of differential geometry theory of nonlinear systems and time-delayed feedback control to realize chaos synthesis in running process of three-phase alternating current (AC) asynchronous motor. The exact linearization approach by state feedback of nonlinear control theory is used for controller design and through simplified analysis on the model of three-phase AC asynchronous motor. Chaos synthesis is got when asynchronous motor running by this controller. Simulink tool in Matlab software is used for Simulation analysis. The simulation results show that the time-delayed state feedback method designed controller implementing chaos synthesis of asynchronous motor is feasible and the control result is satisfied.

  17. Auditory Hallucination

    Directory of Open Access Journals (Sweden)

    MohammadReza Rajabi

    2003-09-01

    Full Text Available Auditory Hallucination or Paracusia is a form of hallucination that involves perceiving sounds without auditory stimulus. A common is hearing one or more talking voices which is associated with psychotic disorders such as schizophrenia or mania. Hallucination, itself, is the most common feature of perceiving the wrong stimulus or to the better word perception of the absence stimulus. Here we will discuss four definitions of hallucinations:1.Perceiving of a stimulus without the presence of any subject; 2. hallucination proper which are the wrong perceptions that are not the falsification of real perception, Although manifest as a new subject and happen along with and synchronously with a real perception;3. hallucination is an out-of-body perception which has no accordance with a real subjectIn a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space. We are going to discuss it in details here.

  18. Feedback as Real-Time Constructions

    Science.gov (United States)

    Keiding, Tina Bering; Qvortrup, Ane

    2014-01-01

    This article offers a re-description of feedback and the significance of time in feedback constructions based on systems theory. It describes feedback as internal, real-time constructions in a learning system. From this perspective, feedback is neither immediate nor delayed, but occurs in the very moment it takes place. This article argues for a…

  19. Feedback as Real-Time Constructions

    Science.gov (United States)

    Keiding, Tina Bering; Qvortrup, Ane

    2014-01-01

    This article offers a re-description of feedback and the significance of time in feedback constructions based on systems theory. It describes feedback as internal, real-time constructions in a learning system. From this perspective, feedback is neither immediate nor delayed, but occurs in the very moment it takes place. This article argues for a…

  20. Multimedia as a Means to Enhance Feedback

    Science.gov (United States)

    Tsutsui, Michio

    2004-01-01

    Interactive feedback, the most common feedback method for oral performance, cannot be used in activities that do not allow for instructor-student interaction, such as speeches and presentations, where feedback should occur after the performance. The conventional ways of providing post-performance or delayed feedback, however, are neither efficient…

  1. Tuning Shifts of the Auditory System By Corticocortical and Corticofugal Projections and Conditioning

    OpenAIRE

    Suga, Nobuo

    2011-01-01

    The central auditory system consists of the lemniscal and nonlemniscal systems. The thalamic lemniscal and non-lemniscal auditory nuclei are different from each other in response properties and neural connectivities. The cortical auditory areas receiving the projections from these thalamic nuclei interact with each other through corticocortical projections and project down to the subcortical auditory nuclei. This corticofugal (descending) system forms multiple feedback loops with the ascendin...

  2. Dynamics of auditory working memory

    Directory of Open Access Journals (Sweden)

    Jochen eKaiser

    2015-05-01

    Full Text Available Working memory denotes the ability to retain stimuli in mind that are no longer physically present and to perform mental operations on them. Electro- and magnetoencephalography allow investigating the short-term maintenance of acoustic stimuli at a high temporal resolution. Studies investigating working memory for non-spatial and spatial auditory information have suggested differential roles of regions along the putative auditory ventral and dorsal streams, respectively, in the processing of the different sound properties. Analyses of event-related potentials have shown sustained, memory load-dependent deflections over the retention periods. The topography of these waves suggested an involvement of modality-specific sensory storage regions. Spectral analysis has yielded information about the temporal dynamics of auditory working memory processing of individual stimuli, showing activation peaks during the delay phase whose timing was related to task performance. Coherence at different frequencies was enhanced between frontal and sensory cortex. In summary, auditory working memory seems to rely on the dynamic interplay between frontal executive systems and sensory representation regions.

  3. Bandwidth enhancement and time-delay signature suppression of chaotic signal from an optical feedback semiconductor laser by using cross phase modulation in a highly nonlinear fiber loop mirror

    Science.gov (United States)

    Wang, Liang-Yan; Zhong, Zhu-Qiong; Wu, Zheng-Mao; Lu, Dong; Chen, Xi; Chen, Jun; Xia, Guang-Qiong

    2016-11-01

    Based on a nonlinear fiber loop mirror (NOLM) composed of a fiber coupler (FC) and a highly nonlinear fiber (HNLF), a scheme is proposed to simultaneously realize the bandwidth enhancement and the time-delay signature (TDS) suppression of a chaotic signal generated from an external cavity optical feedback semiconductor laser. The simulation results show that, after passing through the NOLM, the bandwidth of chaotic signal can be efficiently enhanced and the TDS can be well suppressed under suitable operation parameters. Furthermore, the influences of the power-splitting ratio of the FC, the averaged power of the chaotic signal entering into the FC and the length of the HNLF on the chaotic bandwidth and TDS are analyzed, and the optimized parameters are determined.

  4. Supervisor Feedback.

    Science.gov (United States)

    Hayman, Marilyn J.

    1981-01-01

    Investigated the effectiveness of supervisor feedback in contributing to learning counseling skills. Counselor trainees (N=64) were assigned to supervisor feedback, no supervisor feedback, or control groups for three training sessions. Results indicated counseling skills were learned best by students with no supervisor feedback but self and peer…

  5. Auditory Imagery: Empirical Findings

    Science.gov (United States)

    Hubbard, Timothy L.

    2010-01-01

    The empirical literature on auditory imagery is reviewed. Data on (a) imagery for auditory features (pitch, timbre, loudness), (b) imagery for complex nonverbal auditory stimuli (musical contour, melody, harmony, tempo, notational audiation, environmental sounds), (c) imagery for verbal stimuli (speech, text, in dreams, interior monologue), (d)…

  6. Simple Optoelectronic Feedback in Microwave Oscillators

    Science.gov (United States)

    Maleki, Lute; Iltchenko, Vladimir

    2009-01-01

    A proposed method of stabilizing microwave and millimeter-wave oscillators calls for the use of feedback in optoelectronic delay lines characterized by high values of the resonance quality factor (Q). The method would extend the applicability of optoelectronic feedback beyond the previously reported class of optoelectronic oscillators that comprise two-port electronic amplifiers in closed loops with high-Q feedback circuits.

  7. Auditory imagery: empirical findings.

    Science.gov (United States)

    Hubbard, Timothy L

    2010-03-01

    The empirical literature on auditory imagery is reviewed. Data on (a) imagery for auditory features (pitch, timbre, loudness), (b) imagery for complex nonverbal auditory stimuli (musical contour, melody, harmony, tempo, notational audiation, environmental sounds), (c) imagery for verbal stimuli (speech, text, in dreams, interior monologue), (d) auditory imagery's relationship to perception and memory (detection, encoding, recall, mnemonic properties, phonological loop), and (e) individual differences in auditory imagery (in vividness, musical ability and experience, synesthesia, musical hallucinosis, schizophrenia, amusia) are considered. It is concluded that auditory imagery (a) preserves many structural and temporal properties of auditory stimuli, (b) can facilitate auditory discrimination but interfere with auditory detection, (c) involves many of the same brain areas as auditory perception, (d) is often but not necessarily influenced by subvocalization, (e) involves semantically interpreted information and expectancies, (f) involves depictive components and descriptive components, (g) can function as a mnemonic but is distinct from rehearsal, and (h) is related to musical ability and experience (although the mechanisms of that relationship are not clear).

  8. Positive feedback promotes oscillations in negative feedback loops.

    Directory of Open Access Journals (Sweden)

    Bharath Ananthasubramaniam

    Full Text Available A simple three-component negative feedback loop is a recurring motif in biochemical oscillators. This motif oscillates as it has the three necessary ingredients for oscillations: a three-step delay, negative feedback, and nonlinearity in the loop. However, to oscillate, this motif under the common Goodwin formulation requires a high degree of cooperativity (a measure of nonlinearity in the feedback that is biologically "unlikely." Moreover, this recurring negative feedback motif is commonly observed augmented by positive feedback interactions. Here we show that these positive feedback interactions promote oscillation at lower degrees of cooperativity, and we can thus unify several common kinetic mechanisms that facilitate oscillations, such as self-activation and Michaelis-Menten degradation. The positive feedback loops are most beneficial when acting on the shortest lived component, where they function by balancing the lifetimes of the different components. The benefits of multiple positive feedback interactions are cumulative for a majority of situations considered, when benefits are measured by the reduction in the cooperativity required to oscillate. These positive feedback motifs also allow oscillations with longer periods than that determined by the lifetimes of the components alone. We can therefore conjecture that these positive feedback loops have evolved to facilitate oscillations at lower, kinetically achievable, degrees of cooperativity. Finally, we discuss the implications of our conclusions on the mammalian molecular clock, a system modeled extensively based on the three-component negative feedback loop.

  9. Effects of auditory disruption of lingual tactile sensitivity in skilled and unskilled speaking conditions.

    Science.gov (United States)

    Krummel, S; Petrosino, L; Fucci, D

    1991-10-01

    The purpose of this study was to investigate the effect of disruption of the auditory feedback channel on lingual vibrotactile thresholds obtained under skilled and unskilled speaking conditions. Each of 22 adults was asked to read an English (skilled) and French (unskilled) passage under conditions of normal and altered auditory feedback. Bilateral presentation of masking noise was utilized to disrupt auditory feedback. Before each of the experimental sessions and immediately following a reading, lingual vibrotactile thresholds were obtained. Analysis indicated that the mean differences in the pre- and postvibrotactile threshold measurements of the skilled auditory disrupted condition varied significantly from the mean differences in the pre- and postvibrotactile threshold measurements of the three other conditions. The role of feedback in the speech production of skilled and unskilled speakers is discussed.

  10. Auditory stream biasing in children with reading impairments.

    Science.gov (United States)

    Ouimet, Tialee; Balaban, Evan

    2010-02-01

    Reading impairments have previously been associated with auditory processing differences. We examined auditory stream biasing, a global aspect of auditory temporal processing. Children with reading impairments, control children and adults heard a 10 s long stream-bias-inducing sound sequence (a repeating 1000 Hz tone) and a test sequence (eight repetitions of two pure tones of 1000 and 1420 Hz in an XYX-XYX... pattern) with a variable delay interval (from 0.09 to 8 s) between the two sequences. Reading-impaired children had a significantly lower proportion of streamed responses than control children and adults. Streamed responses in reading-impaired participants differed according to their musical experience, but musically experienced reading-impaired participants were still significantly different from musically experienced controls. Reading impairments are associated with global differences in auditory integration, and musical experience needs to be considered when investigating auditory processing capabilities.

  11. Across frequency processes involved in auditory detection of coloration

    DEFF Research Database (Denmark)

    Buchholz, Jörg; Kerketsos, P

    2008-01-01

    When an early wall reflection is added to a direct sound, a spectral modulation is introduced to the signal's power spectrum. This spectral modulation typically produces an auditory sensation of coloration or pitch. Throughout this study, auditory spectral-integration effects involved in coloration...... detection are investigated. Coloration detection thresholds were therefore measured as a function of reflection delay and stimulus bandwidth. In order to investigate the involved auditory mechanisms, an auditory model was employed that was conceptually similar to the peripheral weighting model [Yost, JASA......, 1982, 416-425]. When a “classical” gammatone filterbank was applied within this spectrum-based model, the model largely underestimated human performance at high signal frequencies. However, this limitation could be resolved by employing an auditory filterbank with narrower filters. This novel...

  12. Mode-locking neurodynamics predict human auditory brainstem responses to musical intervals.

    Science.gov (United States)

    Lerud, Karl D; Almonte, Felix V; Kim, Ji Chul; Large, Edward W

    2014-02-01

    The auditory nervous system is highly nonlinear. Some nonlinear responses arise through active processes in the cochlea, while others may arise in neural populations of the cochlear nucleus, inferior colliculus and higher auditory areas. In humans, auditory brainstem recordings reveal nonlinear population responses to combinations of pure tones, and to musical intervals composed of complex tones. Yet the biophysical origin of central auditory nonlinearities, their signal processing properties, and their relationship to auditory perception remain largely unknown. Both stimulus components and nonlinear resonances are well represented in auditory brainstem nuclei due to neural phase-locking. Recently mode-locking, a generalization of phase-locking that implies an intrinsically nonlinear processing of sound, has been observed in mammalian auditory brainstem nuclei. Here we show that a canonical model of mode-locked neural oscillation predicts the complex nonlinear population responses to musical intervals that have been observed in the human brainstem. The model makes predictions about auditory signal processing and perception that are different from traditional delay-based models, and may provide insight into the nature of auditory population responses. We anticipate that the application of dynamical systems analysis will provide the starting point for generic models of auditory population dynamics, and lead to a deeper understanding of nonlinear auditory signal processing possibly arising in excitatory-inhibitory networks of the central auditory nervous system. This approach has the potential to link neural dynamics with the perception of pitch, music, and speech, and lead to dynamical models of auditory system development.

  13. Motor Training: Comparison of Visual and Auditory Coded Proprioceptive Cues

    Directory of Open Access Journals (Sweden)

    Philip Jepson

    2012-05-01

    Full Text Available Self-perception of body posture and movement is achieved through multi-sensory integration, particularly the utilisation of vision, and proprioceptive information derived from muscles and joints. Disruption to these processes can occur following a neurological accident, such as stroke, leading to sensory and physical impairment. Rehabilitation can be helped through use of augmented visual and auditory biofeedback to stimulate neuro-plasticity, but the effective design and application of feedback, particularly in the auditory domain, is non-trivial. Simple auditory feedback was tested by comparing the stepping accuracy of normal subjects when given a visual spatial target (step length and an auditory temporal target (step duration. A baseline measurement of step length and duration was taken using optical motion capture. Subjects (n=20 took 20 ‘training’ steps (baseline ±25% using either an auditory target (950 Hz tone, bell-shaped gain envelope or visual target (spot marked on the floor and were then asked to replicate the target step (length or duration corresponding to training with all feedback removed. Visual cues (mean percentage error=11.5%; SD ± 7.0%; auditory cues (mean percentage error = 12.9%; SD ± 11.8%. Visual cues elicit a high degree of accuracy both in training and follow-up un-cued tasks; despite the novelty of the auditory cues present for subjects, the mean accuracy of subjects approached that for visual cues, and initial results suggest a limited amount of practice using auditory cues can improve performance.

  14. Auditory processing in children : a study of the effects of age, hearing impairment and language impairment on auditory abilities in children

    NARCIS (Netherlands)

    Stollman, Martin Hubertus Petrus

    2003-01-01

    In this thesis we tested the hypotheses that the auditory system of children continues to mature until at least the age of 12 years and that the development of auditory processing in hearing-impaired and language-impaired children is often delayed or even genuinely disturbed. Data from a longitudin

  15. Resizing Auditory Communities

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2012-01-01

    Heard through the ears of the Canadian composer and music teacher R. Murray Schafer the ideal auditory community had the shape of a village. Schafer’s work with the World Soundscape Project in the 70s represent an attempt to interpret contemporary environments through musical and auditory...

  16. Role of the auditory system in speech production.

    Science.gov (United States)

    Guenther, Frank H; Hickok, Gregory

    2015-01-01

    This chapter reviews evidence regarding the role of auditory perception in shaping speech output. Evidence indicates that speech movements are planned to follow auditory trajectories. This in turn is followed by a description of the Directions Into Velocities of Articulators (DIVA) model, which provides a detailed account of the role of auditory feedback in speech motor development and control. A brief description of the higher-order brain areas involved in speech sequencing (including the pre-supplementary motor area and inferior frontal sulcus) is then provided, followed by a description of the Hierarchical State Feedback Control (HSFC) model, which posits internal error detection and correction processes that can detect and correct speech production errors prior to articulation. The chapter closes with a treatment of promising future directions of research into auditory-motor interactions in speech, including the use of intracranial recording techniques such as electrocorticography in humans, the investigation of the potential roles of various large-scale brain rhythms in speech perception and production, and the development of brain-computer interfaces that use auditory feedback to allow profoundly paralyzed users to learn to produce speech using a speech synthesizer.

  17. The effect of superior auditory skills on vocal accuracy

    Science.gov (United States)

    Amir, Ofer; Amir, Noam; Kishon-Rabin, Liat

    2003-02-01

    The relationship between auditory perception and vocal production has been typically investigated by evaluating the effect of either altered or degraded auditory feedback on speech production in either normal hearing or hearing-impaired individuals. Our goal in the present study was to examine this relationship in individuals with superior auditory abilities. Thirteen professional musicians and thirteen nonmusicians, with no vocal or singing training, participated in this study. For vocal production accuracy, subjects were presented with three tones. They were asked to reproduce the pitch using the vowel /a/. This procedure was repeated three times. The fundamental frequency of each production was measured using an autocorrelation pitch detection algorithm designed for this study. The musicians' superior auditory abilities (compared to the nonmusicians) were established in a frequency discrimination task reported elsewhere. Results indicate that (a) musicians had better vocal production accuracy than nonmusicians (production errors of 1/2 a semitone compared to 1.3 semitones, respectively); (b) frequency discrimination thresholds explain 43% of the variance of the production data, and (c) all subjects with superior frequency discrimination thresholds showed accurate vocal production; the reverse relationship, however, does not hold true. In this study we provide empirical evidence to the importance of auditory feedback on vocal production in listeners with superior auditory skills.

  18. Time-varying auditory gain control in response to double-pulse stimuli in harbour porpoises is not mediated by a stapedial reflex

    Directory of Open Access Journals (Sweden)

    Asger Emil Munch Schrøder

    2017-04-01

    Full Text Available Echolocating animals reduce their output level and hearing sensitivity with decreasing echo delays, presumably to stabilize the perceived echo intensity during target approaches. In bats, this variation in hearing sensitivity is formed by a call-induced stapedial reflex that tapers off over time after the call. Here, we test the hypothesis that a similar mechanism exists in toothed whales by subjecting a trained harbour porpoise to a series of double sound pulses varying in delay and frequency, while measuring the magnitudes of the evoked auditory brainstem responses (ABRs. We find that the recovery of the ABR to the second pulse is frequency dependent, and that a stapedial reflex therefore cannot account for the reduced hearing sensitivity at short pulse delays. We propose that toothed whale auditory time-varying gain control during echolocation is not enabled by the middle ear as in bats, but rather by frequency-dependent mechanisms such as forward masking and perhaps higher-order control of efferent feedback to the outer hair cells.

  19. Tuning up the developing auditory CNS.

    Science.gov (United States)

    Sanes, Dan H; Bao, Shaowen

    2009-04-01

    Although the auditory system has limited information processing resources, the acoustic environment is infinitely variable. To properly encode the natural environment, the developing central auditory system becomes somewhat specialized through experience-dependent adaptive mechanisms that operate during a sensitive time window. Recent studies have demonstrated that cellular and synaptic plasticity occurs throughout the central auditory pathway. Acoustic-rearing experiments can lead to an over-representation of the exposed sound frequency, and this is associated with specific changes in frequency discrimination. These forms of cellular plasticity are manifest in brain regions, such as midbrain and cortex, which interact through feed-forward and feedback pathways. Hearing loss leads to a profound re-weighting of excitatory and inhibitory synaptic gain throughout the auditory CNS, and this is associated with an over-excitability that is observed in vivo. Further behavioral and computational analyses may provide insights into how theses cellular and systems plasticity effects underlie the development of cognitive functions such as speech perception.

  20. Formativ Feedback

    DEFF Research Database (Denmark)

    Hyldahl, Kirsten Kofod

    Denne bog undersøger, hvordan lærere kan anvende feedback til at forbedre undervisningen i klasselokalet. I denne sammenhæng har John Hattie, professor ved Melbourne Universitet, udviklet en model for feedback, hvilken er baseret på synteser af meta-analyser. I 2009 udgav han bogen "Visible...

  1. Low-frequency versus high-frequency synchronisation in chirp-evoked auditory brainstem responses

    DEFF Research Database (Denmark)

    Rønne, Filip Munch; Gøtsche-Rasmussen, Kristian

    2011-01-01

    This study investigates the frequency specific contribution to the auditory brainstem response (ABR) of chirp stimuli. Frequency rising chirps were designed to compensate for the cochlear traveling wave delay, and lead to larger wave-V amplitudes than for click stimuli as more auditory nerve fibr...

  2. Translation and adaptation of functional auditory performance indicators (FAPI

    Directory of Open Access Journals (Sweden)

    Karina Ferreira

    2011-12-01

    Full Text Available Work with deaf children has gained new attention since the expectation and goal of therapy has expanded to language development and subsequent language learning. Many clinical tests were developed for evaluation of speech sound perception in young children in response to the need for accurate assessment of hearing skills that developed from the use of individual hearing aids or cochlear implants. These tests also allow the evaluation of the rehabilitation program. However, few of these tests are available in Portuguese. Evaluation with the Functional Auditory Performance Indicators (FAPI generates a child's functional auditory skills profile, which lists auditory skills in an integrated and hierarchical order. It has seven hierarchical categories, including sound awareness, meaningful sound, auditory feedback, sound source localizing, auditory discrimination, short-term auditory memory, and linguistic auditory processing. FAPI evaluation allows the therapist to map the child's hearing profile performance, determine the target for increasing the hearing abilities, and develop an effective therapeutic plan. Objective: Since the FAPI is an American test, the inventory was adapted for application in the Brazilian population. Material and Methods: The translation was done following the steps of translation and back translation, and reproducibility was evaluated. Four translated versions (two originals and two back-translated were compared, and revisions were done to ensure language adaptation and grammatical and idiomatic equivalence. Results: The inventory was duly translated and adapted. Conclusion: Further studies about the application of the translated FAPI are necessary to make the test practicable in Brazilian clinical use.

  3. Contextual modulation of primary visual cortex by auditory signals.

    Science.gov (United States)

    Petro, L S; Paton, A T; Muckli, L

    2017-02-19

    Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195-201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256-1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame.This article is part of the themed issue 'Auditory and visual scene analysis'.

  4. Contextual modulation of primary visual cortex by auditory signals

    Science.gov (United States)

    Paton, A. T.

    2017-01-01

    Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195–201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256–1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame. This article is part of the themed issue ‘Auditory and visual scene analysis’. PMID:28044015

  5. The plastic ear and perceptual relearning in auditory spatial perception.

    Science.gov (United States)

    Carlile, Simon

    2014-01-01

    The auditory system of adult listeners has been shown to accommodate to altered spectral cues to sound location which presumably provides the basis for recalibration to changes in the shape of the ear over a life time. Here we review the role of auditory and non-auditory inputs to the perception of sound location and consider a range of recent experiments looking at the role of non-auditory inputs in the process of accommodation to these altered spectral cues. A number of studies have used small ear molds to modify the spectral cues that result in significant degradation in localization performance. Following chronic exposure (10-60 days) performance recovers to some extent and recent work has demonstrated that this occurs for both audio-visual and audio-only regions of space. This begs the questions as to the teacher signal for this remarkable functional plasticity in the adult nervous system. Following a brief review of influence of the motor state in auditory localization, we consider the potential role of auditory-motor learning in the perceptual recalibration of the spectral cues. Several recent studies have considered how multi-modal and sensory-motor feedback might influence accommodation to altered spectral cues produced by ear molds or through virtual auditory space stimulation using non-individualized spectral cues. The work with ear molds demonstrates that a relatively short period of training involving audio-motor feedback (5-10 days) significantly improved both the rate and extent of accommodation to altered spectral cues. This has significant implications not only for the mechanisms by which this complex sensory information is encoded to provide spatial cues but also for adaptive training to altered auditory inputs. The review concludes by considering the implications for rehabilitative training with hearing aids and cochlear prosthesis.

  6. The plastic ear and perceptual relearning in auditory spatial perception.

    Directory of Open Access Journals (Sweden)

    Simon eCarlile

    2014-08-01

    Full Text Available The auditory system of adult listeners has been shown to accommodate to altered spectral cues to sound location which presumably provides the basis for recalibration to changes in the shape of the ear over a life time. Here we review the role of auditory and non-auditory inputs to the perception of sound location and consider a range of recent experiments looking at the role of non-auditory inputs in the process of accommodation to these altered spectral cues. A number of studies have used small ear moulds to modify the spectral cues that result in significant degradation in localization performance. Following chronic exposure (10-60 days performance recovers to some extent and recent work has demonstrated that this occurs for both audio-visual and audio-only regions of space. This begs the questions as to the teacher signal for this remarkable functional plasticity in the adult nervous system. Following a brief review of influence of the motor state in auditory localisation, we consider the potential role of auditory-motor learning in the perceptual recalibration of the spectral cues. Several recent studies have considered how multi-modal and sensory-motor feedback might influence accommodation to altered spectral cues produced by ear moulds or through virtual auditory space stimulation using non-individualised spectral cues. The work with ear moulds demonstrates that a relatively short period of training involving sensory-motor feedback (5 – 10 days significantly improved both the rate and extent of accommodation to altered spectral cues. This has significant implications not only for the mechanisms by which this complex sensory information is encoded to provide a spatial code but also for adaptive training to altered auditory inputs. The review concludes by considering the implications for rehabilitative training with hearing aids and cochlear prosthesis.

  7. Auditory Integration Training

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2002-07-01

    Full Text Available Auditory integration training (AIT is a hearing enhancement training process for sensory input anomalies found in individuals with autism, attention deficit hyperactive disorder, dyslexia, hyperactivity, learning disability, language impairments, pervasive developmental disorder, central auditory processing disorder, attention deficit disorder, depressin, and hyperacute hearing. AIT, recently introduced in the United States, and has received much notice of late following the release of The Sound of a Moracle, by Annabel Stehli. In her book, Mrs. Stehli describes before and after auditory integration training experiences with her daughter, who was diagnosed at age four as having autism.

  8. Feedback as real-time constructions

    DEFF Research Database (Denmark)

    Keiding, Tina Bering; Qvortrup, Ane

    2014-01-01

    This article offers a re-description of feedback and the significance of time in feedback constructions based on systems theory. It describes feedback as internal, real-time constructions in a learning system. From this perspective, feedback is neither immediate nor delayed, but occurs in the very...... instant it takes place. This article argues for a clear distinction between the timing of communicative events, such as responses that are provided as help for feedback constructions, and the feedback construction itself as an event in a psychic system. Although feedback is described as an internal......, system-relative construction, different teaching environments offer diverse conditions for feedback constructions. The final section of this article explores this idea with the help of examples from both synchronous oral interaction and asynchronous text-based interaction mediated by digital media....

  9. Auditory Responses of Infants

    Science.gov (United States)

    Watrous, Betty Springer; And Others

    1975-01-01

    Forty infants, 3- to 12-months-old, participated in a study designed to differentiate the auditory response characteristics of normally developing infants in the age ranges 3 - 5 months, 6 - 8 months, and 9 - 12 months. (Author)

  10. Temporal sequence of visuo-auditory interaction in multiple areas of the guinea pig visual cortex.

    Directory of Open Access Journals (Sweden)

    Masataka Nishimura

    Full Text Available Recent studies in humans and monkeys have reported that acoustic stimulation influences visual responses in the primary visual cortex (V1. Such influences can be generated in V1, either by direct auditory projections or by feedback projections from extrastriate cortices. To test these hypotheses, cortical activities were recorded using optical imaging at a high spatiotemporal resolution from multiple areas of the guinea pig visual cortex, to visual and/or acoustic stimulations. Visuo-auditory interactions were evaluated according to differences between responses evoked by combined auditory and visual stimulation, and the sum of responses evoked by separate visual and auditory stimulations. Simultaneous presentation of visual and acoustic stimulations resulted in significant interactions in V1, which occurred earlier than in other visual areas. When acoustic stimulation preceded visual stimulation, significant visuo-auditory interactions were detected only in V1. These results suggest that V1 is a cortical origin of visuo-auditory interaction.

  11. Delay-dependent observer-based stabilizing controller design for linear multiple state-delayed systems

    Institute of Scientific and Technical Information of China (English)

    Dejin WANG

    2003-01-01

    This article concerns a coupled LMIs approach to delay-dependent observer-based output feedback stabilizing controller design for linear continuous-time systems with multiple state delays. The advantage of our proposed delay-dependent coupled LMIs criterion lies in that: (1) it can optimize one of multiple time delays with others selected properly, and at the same time, the feedback-gain and observer-gain can be obtained, respectively. (2) it is less conservative than the existing delay-independent ones in the literature. Algorithm to solve the coupled LMIs is also given. Numerical examples illustrate the effectiveness of our method.

  12. Isochronal synchronization of time delay and delay-coupled chaotic systems

    Energy Technology Data Exchange (ETDEWEB)

    Grzybowski, J M V; Yoneyama, T [Instituto Tecnologico de Aeronautica, ITA, Praca Marechal Eduardo Gomes, 50, Vila das Acacias, Sao Jose dos Campos, SP, Brazil, CEP 12.228-900 (Brazil); Macau, E E N, E-mail: zzmariovic@yahoo.com.br, E-mail: elbert@lac.inpe.br, E-mail: takashi@ita.br [Instituto Nacional de Pesquisas Espaciais, INPE, PO Box 515, Sao Jose dos Campos, SP, Brazil, CEP 12.227-010 (Brazil)

    2011-04-29

    This paper studies the problem of isochronal synchronization of time-delay chaotic systems featuring also coupling delay. Based on the Lyapunov-Krasovskii stability theory, sufficient conditions are derived for the stability of isochronal synchronization between a pair of identical chaotic systems. Such criteria permit the proper design of stable proportional linear feedback controller, more specifically, the design of adequate proportional feedback gain matrices. The proposed criteria are suited to systems with (i) intrinsic delay, (ii) coupling delay or (iii) both. Numerical simulations of the synchronization of delay-coupled systems are presented as examples of the application of the criteria.

  13. Music lessons improve auditory perceptual and cognitive performance in deaf children.

    Science.gov (United States)

    Rochette, Françoise; Moussard, Aline; Bigand, Emmanuel

    2014-01-01

    Despite advanced technologies in auditory rehabilitation of profound deafness, deaf children often exhibit delayed cognitive and linguistic development and auditory training remains a crucial element of their education. In the present cross-sectional study, we assess whether music would be a relevant tool for deaf children rehabilitation. In normal-hearing children, music lessons have been shown to improve cognitive and linguistic-related abilities, such as phonetic discrimination and reading. We compared auditory perception, auditory cognition, and phonetic discrimination between 14 profoundly deaf children who completed weekly music lessons for a period of 1.5-4 years and 14 deaf children who did not receive musical instruction. Children were assessed on perceptual and cognitive auditory tasks using environmental sounds: discrimination, identification, auditory scene analysis, auditory working memory. Transfer to the linguistic domain was tested with a phonetic discrimination task. Musically trained children showed better performance in auditory scene analysis, auditory working memory and phonetic discrimination tasks, and multiple regressions showed that success on these tasks was at least partly driven by music lessons. We propose that musical education contributes to development of general processes such as auditory attention and perception, which, in turn, facilitate auditory-related cognitive and linguistic processes.

  14. Music lessons improve auditory perceptual and cognitive performance in deaf children

    Directory of Open Access Journals (Sweden)

    Françoise eROCHETTE

    2014-07-01

    Full Text Available Despite advanced technologies in auditory rehabilitation of profound deafness, deaf children often exhibit delayed cognitive and linguistic development and auditory training remains a crucial element of their education. In the present cross-sectional study, we assess whether music would be a relevant tool for deaf children rehabilitation. In normal-hearing children, music lessons have been shown to improve cognitive and linguistic-related abilities, such as phonetic discrimination and reading. We compared auditory perception, auditory cognition, and phonetic discrimination between 14 profoundly deaf children who completed weekly music lessons for a period of 1.5 to 4 years and 14 deaf children who did not receive musical instruction. Children were assessed on perceptual and cognitive auditory tasks using environmental sounds: discrimination, identification, auditory scene analysis, auditory working memory. Transfer to the linguistic domain was tested with a phonetic discrimination task. Musically-trained children showed better performance in auditory scene analysis, auditory working memory and phonetic discrimination tasks, and multiple regressions showed that success on these tasks was at least partly driven by music lessons. We propose that musical education contributes to development of general processes such as auditory attention and perception, which, in turn, facilitate auditory-related cognitive and linguistic processes.

  15. The Accuracy of Computer-Assisted Feedback and Students' Responses to It

    Science.gov (United States)

    Lavolette, Elizabeth; Polio, Charlene; Kahng, Jimin

    2015-01-01

    Various researchers in second language acquisition have argued for the effectiveness of immediate rather than delayed feedback. In writing, truly immediate feedback is impractical, but computer-assisted feedback provides a quick way of providing feedback that also reduces the teacher's workload. We explored the accuracy of feedback from…

  16. The Auditory Verbal Learning Test (Rey AVLT): An Arabic Version

    Science.gov (United States)

    Sharoni, Varda; Natur, Nazeh

    2014-01-01

    The goals of this study were to adapt the Rey Auditory Verbal Learning Test (AVLT) into Arabic, to compare recall functioning among age groups (6:0 to 17:11), and to compare gender differences on various memory dimensions (immediate and delayed recall, learning rate, recognition, proactive interferences, and retroactive interferences). This…

  17. Auditory Technology and Its Impact on Bilingual Deaf Education

    Science.gov (United States)

    Mertes, Jennifer

    2015-01-01

    Brain imaging studies suggest that children can simultaneously develop, learn, and use two languages. A visual language, such as American Sign Language (ASL), facilitates development at the earliest possible moments in a child's life. Spoken language development can be delayed due to diagnostic evaluations, device fittings, and auditory skill…

  18. Auditory hallucinations induced by trazodone.

    Science.gov (United States)

    Shiotsuki, Ippei; Terao, Takeshi; Ishii, Nobuyoshi; Hatano, Koji

    2014-04-03

    A 26-year-old female outpatient presenting with a depressive state suffered from auditory hallucinations at night. Her auditory hallucinations did not respond to blonanserin or paliperidone, but partially responded to risperidone. In view of the possibility that her auditory hallucinations began after starting trazodone, trazodone was discontinued, leading to a complete resolution of her auditory hallucinations. Furthermore, even after risperidone was decreased and discontinued, her auditory hallucinations did not recur. These findings suggest that trazodone may induce auditory hallucinations in some susceptible patients.

  19. Tuning shifts of the auditory system by corticocortical and corticofugal projections and conditioning.

    Science.gov (United States)

    Suga, Nobuo

    2012-02-01

    The central auditory system consists of the lemniscal and nonlemniscal systems. The thalamic lemniscal and nonlemniscal auditory nuclei are different from each other in response properties and neural connectivities. The cortical auditory areas receiving the projections from these thalamic nuclei interact with each other through corticocortical projections and project down to the subcortical auditory nuclei. This corticofugal (descending) system forms multiple feedback loops with the ascending system. The corticocortical and corticofugal projections modulate auditory signal processing and play an essential role in the plasticity of the auditory system. Focal electric stimulation - comparable to repetitive tonal stimulation - of the lemniscal system evokes three major types of changes in the physiological properties, such as the tuning to specific values of acoustic parameters of cortical and subcortical auditory neurons through different combinations of facilitation and inhibition. For such changes, a neuromodulator, acetylcholine, plays an essential role. Electric stimulation of the nonlemniscal system evokes changes in the lemniscal system that is different from those evoked by the lemniscal stimulation. Auditory signals ascending from the lemniscal and nonlemniscal thalamic nuclei to the cortical auditory areas appear to be selected or adjusted by a "differential" gating mechanism. Conditioning for associative learning and pseudo-conditioning for nonassociative learning respectively elicit tone-specific and nonspecific plastic changes. The lemniscal, corticofugal and cholinergic systems are involved in eliciting the former, but not the latter. The current article reviews the recent progress in the research of corticocortical and corticofugal modulations of the auditory system and its plasticity elicited by conditioning and pseudo-conditioning.

  20. Feedback and Incentives

    DEFF Research Database (Denmark)

    Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie Claire

    2009-01-01

    This paper experimentally investigates the impact of different pay schemes and relative performance feedback policies on employee effort. We explore three feedback rules: no feedback on relative performance, feedback given halfway through the production period, and continuously updated feedback. ...

  1. Feedback-based error monitoring processes during musical performance: an ERP study.

    Science.gov (United States)

    Katahira, Kentaro; Abla, Dilshat; Masuda, Sayaka; Okanoya, Kazuo

    2008-05-01

    Auditory feedback is important in detecting and correcting errors during sound production when a current performance is compared to an intended performance. In the context of vocal production, a forward model, in which a prediction of action consequence (corollary discharge) is created, has been proposed to explain the dampened activity of the auditory cortex while producing self-generated vocal sounds. However, it is unclear how auditory feedback is processed and what neural mechanism underlies the process during other sound production behavior, such as musical performances. We investigated the neural correlates of human auditory feedback-based error detection using event-related potentials (ERPs) recorded during musical performances. Keyboard players of two different skill levels played simple melodies using a musical score. During the performance, the auditory feedback was occasionally altered. Subjects with early and extensive piano training produced a negative ERP component N210, which was absent in non-trained players. When subjects listened to music that deviated from a corresponding score without playing the piece, N210 did not emerge but the imaginary mismatch negativity (iMMN) did. Therefore, N210 may reflect a process of mismatch between the intended auditory image evoked by motor activity, and actual auditory feedback.

  2. Magnetoencephalographic Imaging of Auditory and Somatosensory Cortical Responses in Children with Autism and Sensory Processing Dysfunction

    Science.gov (United States)

    Demopoulos, Carly; Yu, Nina; Tripp, Jennifer; Mota, Nayara; Brandes-Aitken, Anne N.; Desai, Shivani S.; Hill, Susanna S.; Antovich, Ashley D.; Harris, Julia; Honma, Susanne; Mizuiri, Danielle; Nagarajan, Srikantan S.; Marco, Elysa J.

    2017-01-01

    This study compared magnetoencephalographic (MEG) imaging-derived indices of auditory and somatosensory cortical processing in children aged 8–12 years with autism spectrum disorder (ASD; N = 18), those with sensory processing dysfunction (SPD; N = 13) who do not meet ASD criteria, and typically developing control (TDC; N = 19) participants. The magnitude of responses to both auditory and tactile stimulation was comparable across all three groups; however, the M200 latency response from the left auditory cortex was significantly delayed in the ASD group relative to both the TDC and SPD groups, whereas the somatosensory response of the ASD group was only delayed relative to TDC participants. The SPD group did not significantly differ from either group in terms of somatosensory latency, suggesting that participants with SPD may have an intermediate phenotype between ASD and TDC with regard to somatosensory processing. For the ASD group, correlation analyses indicated that the left M200 latency delay was significantly associated with performance on the WISC-IV Verbal Comprehension Index as well as the DSTP Acoustic-Linguistic index. Further, these cortical auditory response delays were not associated with somatosensory cortical response delays or cognitive processing speed in the ASD group, suggesting that auditory delays in ASD are domain specific rather than associated with generalized processing delays. The specificity of these auditory delays to the ASD group, in addition to their correlation with verbal abilities, suggests that auditory sensory dysfunction may be implicated in communication symptoms in ASD, motivating further research aimed at understanding the impact of sensory dysfunction on the developing brain. PMID:28603492

  3. Magnetoencephalographic Imaging of Auditory and Somatosensory Cortical Responses in Children with Autism and Sensory Processing Dysfunction

    Directory of Open Access Journals (Sweden)

    Carly Demopoulos

    2017-05-01

    Full Text Available This study compared magnetoencephalographic (MEG imaging-derived indices of auditory and somatosensory cortical processing in children aged 8–12 years with autism spectrum disorder (ASD; N = 18, those with sensory processing dysfunction (SPD; N = 13 who do not meet ASD criteria, and typically developing control (TDC; N = 19 participants. The magnitude of responses to both auditory and tactile stimulation was comparable across all three groups; however, the M200 latency response from the left auditory cortex was significantly delayed in the ASD group relative to both the TDC and SPD groups, whereas the somatosensory response of the ASD group was only delayed relative to TDC participants. The SPD group did not significantly differ from either group in terms of somatosensory latency, suggesting that participants with SPD may have an intermediate phenotype between ASD and TDC with regard to somatosensory processing. For the ASD group, correlation analyses indicated that the left M200 latency delay was significantly associated with performance on the WISC-IV Verbal Comprehension Index as well as the DSTP Acoustic-Linguistic index. Further, these cortical auditory response delays were not associated with somatosensory cortical response delays or cognitive processing speed in the ASD group, suggesting that auditory delays in ASD are domain specific rather than associated with generalized processing delays. The specificity of these auditory delays to the ASD group, in addition to their correlation with verbal abilities, suggests that auditory sensory dysfunction may be implicated in communication symptoms in ASD, motivating further research aimed at understanding the impact of sensory dysfunction on the developing brain.

  4. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition ...... mineral density) and psychological (e.g., low self-esteem) and underline the importance of careful clinical assessment of the patients.......Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition...

  5. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  6. Auditory and Visual Sensations

    CERN Document Server

    Ando, Yoichi

    2010-01-01

    Professor Yoichi Ando, acoustic architectural designer of the Kirishima International Concert Hall in Japan, presents a comprehensive rational-scientific approach to designing performance spaces. His theory is based on systematic psychoacoustical observations of spatial hearing and listener preferences, whose neuronal correlates are observed in the neurophysiology of the human brain. A correlation-based model of neuronal signal processing in the central auditory system is proposed in which temporal sensations (pitch, timbre, loudness, duration) are represented by an internal autocorrelation representation, and spatial sensations (sound location, size, diffuseness related to envelopment) are represented by an internal interaural crosscorrelation function. Together these two internal central auditory representations account for the basic auditory qualities that are relevant for listening to music and speech in indoor performance spaces. Observed psychological and neurophysiological commonalities between auditor...

  7. Frequent external focus feedback enhances motor learning

    Directory of Open Access Journals (Sweden)

    Gabriele eWulf

    2010-11-01

    Full Text Available The present study examined the hypothesis that feedback inducing an external focus of attention enhances motor learning if it is provided frequently (i.e., 100% rather than less frequently. Children (10-12 year olds practiced a soccer throw-in task and were provided feedback about movement form. The feedback statements, provided either after every (100% or every third (33% practice trial, were similar in content but induced either an internal focus (body-movement related or external focus (movement-effect related. The results demonstrated that learning of the movement form was enhanced by external-focus feedback after every trial (100% relative to external-focus feedback after every third trial (33% or internal-focus feedback (100%, 33%, as demonstrated by immediate and delayed transfer tests without feedback. There was no difference between the two internal-focus feedback groups. These findings indicate that the attentional focus induced by feedback is an important factor in determining the effectiveness of different feedback frequencies. We argue that the informational properties of feedback cannot sufficiently account for these and related findings, and suggest that the attentional role of feedback be given greater consideration in future studies.

  8. Auditory function in individuals within Leber's hereditary optic neuropathy pedigrees.

    Science.gov (United States)

    Rance, Gary; Kearns, Lisa S; Tan, Johanna; Gravina, Anthony; Rosenfeld, Lisa; Henley, Lauren; Carew, Peter; Graydon, Kelley; O'Hare, Fleur; Mackey, David A

    2012-03-01

    The aims of this study are to investigate whether auditory dysfunction is part of the spectrum of neurological abnormalities associated with Leber's hereditary optic neuropathy (LHON) and to determine the perceptual consequences of auditory neuropathy (AN) in affected listeners. Forty-eight subjects confirmed by genetic testing as having one of four mitochondrial mutations associated with LHON (mt11778, mtDNA14484, mtDNA14482 and mtDNA3460) participated. Thirty-two of these had lost vision, and 16 were asymptomatic at the point of data collection. While the majority of individuals showed normal sound detection, >25% (of both symptomatic and asymptomatic participants) showed electrophysiological evidence of AN with either absent or severely delayed auditory brainstem potentials. Abnormalities were observed for each of the mutations, but subjects with the mtDNA11778 type were the most affected. Auditory perception was also abnormal in both symptomatic and asymptomatic subjects, with >20% of cases showing impaired detection of auditory temporal (timing) cues and >30% showing abnormal speech perception both in quiet and in the presence of background noise. The findings of this study indicate that a relatively high proportion of individuals with the LHON genetic profile may suffer functional hearing difficulties due to neural abnormality in the central auditory pathways.

  9. Broadband hyperchaotic oscillator with delay line

    DEFF Research Database (Denmark)

    Cenys, Antanas; Lindberg, Erik; Anagnostopoulos, A. N.;

    2002-01-01

    Dynamical systems with time delay can be employed as high dimensional hyperchaotic oscillators with multiple positive Lyapunov exponents. We describe an electronic circuit composed of a 3-stage amplifier and a delay line in the feedback loop. The 1st stage of the amplifier is a nonlinear one while...

  10. Effects of digital vibrotactile speech feedback on overt stuttering frequency.

    Science.gov (United States)

    Snyder, Gregory J; Blanchet, Paul; Waddell, Dwight; Ivy, Lennette J

    2009-02-01

    Fluency-enhancing speech feedback, originating from internally or externally generated sources via auditory or visual sensory modalities is not restricted to a specific sensory modality or signal origination. Research suggests that externally generated digital vibrotactile speech feedback serves as an effective fluency enhancer. The present purpose was to test the fluency-enhancing effects of self-generated digital vibrotactile speech feedback on stuttering frequency. Adults who stutter read passages aloud over the telephone, both with and without digital vibrotactile speech feedback. Digital vibrotactile speech feedback was operationally defined as feeling the vibrations of the thyroid cartilage with the thumb and index finger while speaking. Analysis indicated that self-generated digital vibrotactile speech feedback reduced overt stuttering frequency by an average of 72%. As the specific neural mechanisms associated with stuttering and fluency enhancement from tactile speech feedback remain unknown, theoretical implications and clinical applications were discussed.

  11. Auditory evacuation beacons

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Bronkhorst, A.W.; Boer, L.C.

    2005-01-01

    Auditory evacuation beacons can be used to guide people to safe exits, even when vision is totally obscured by smoke. Conventional beacons make use of modulated noise signals. Controlled evacuation experiments show that such signals require explicit instructions and are often misunderstood. A new si

  12. Virtual Auditory Displays

    Science.gov (United States)

    2000-01-01

    timbre , intensity, distance, room modeling, radio communication Virtual Environments Handbook Chapter 4 Virtual Auditory Displays Russell D... musical note “A” as a pure sinusoid, there will be 440 condensations and rarefactions per second. The distance between two adjacent condensations or...and complexity are pitch, loudness, and timbre respectively. This distinction between physical and perceptual measures of sound properties is an

  13. The neglected neglect: auditory neglect.

    Science.gov (United States)

    Gokhale, Sankalp; Lahoti, Sourabh; Caplan, Louis R

    2013-08-01

    Whereas visual and somatosensory forms of neglect are commonly recognized by clinicians, auditory neglect is often not assessed and therefore neglected. The auditory cortical processing system can be functionally classified into 2 distinct pathways. These 2 distinct functional pathways deal with recognition of sound ("what" pathway) and the directional attributes of the sound ("where" pathway). Lesions of higher auditory pathways produce distinct clinical features. Clinical bedside evaluation of auditory neglect is often difficult because of coexisting neurological deficits and the binaural nature of auditory inputs. In addition, auditory neglect and auditory extinction may show varying degrees of overlap, which makes the assessment even harder. Shielding one ear from the other as well as separating the ear from space is therefore critical for accurate assessment of auditory neglect. This can be achieved by use of specialized auditory tests (dichotic tasks and sound localization tests) for accurate interpretation of deficits. Herein, we have reviewed auditory neglect with an emphasis on the functional anatomy, clinical evaluation, and basic principles of specialized auditory tests.

  14. Auditory-motor learning during speech production in 9-11-year-old children.

    Directory of Open Access Journals (Sweden)

    Douglas M Shiller

    Full Text Available BACKGROUND: Hearing ability is essential for normal speech development, however the precise mechanisms linking auditory input and the improvement of speaking ability remain poorly understood. Auditory feedback during speech production is believed to play a critical role by providing the nervous system with information about speech outcomes that is used to learn and subsequently fine-tune speech motor output. Surprisingly, few studies have directly investigated such auditory-motor learning in the speech production of typically developing children. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we manipulated auditory feedback during speech production in a group of 9-11-year old children, as well as in adults. Following a period of speech practice under conditions of altered auditory feedback, compensatory changes in speech production and perception were examined. Consistent with prior studies, the adults exhibited compensatory changes in both their speech motor output and their perceptual representations of speech sound categories. The children exhibited compensatory changes in the motor domain, with a change in speech output that was similar in magnitude to that of the adults, however the children showed no reliable compensatory effect on their perceptual representations. CONCLUSIONS: The results indicate that 9-11-year-old children, whose speech motor and perceptual abilities are still not fully developed, are nonetheless capable of auditory-feedback-based sensorimotor adaptation, supporting a role for such learning processes in speech motor development. Auditory feedback may play a more limited role, however, in the fine-tuning of children's perceptual representations of speech sound categories.

  15. Adaptive control for a class of discrete-time time-delay systems with regard to delay parameter

    Institute of Scientific and Technical Information of China (English)

    Chai Lin; Cheng Ming; Fei Shumin; Zhai Junyong

    2009-01-01

    The memory state feedback control problem for a class of discrete-time systems with input delay and unknown state delay is addressed based on LMIs and Lyapunov-Krasovskii functional method. Under the action of our designed adaptive control law, the unknown time-delay parameter is included in memory state feedback controller. Using LMI technique, delay-dependent sufficient conditions for the existence of the feedback controller are obtained. Finally, the effectiveness of the proposed design method is demonstrated by a numerical example.

  16. Simultaneously-evoked auditory potentials (SEAP): A new method for concurrent measurement of cortical and subcortical auditory-evoked activity.

    Science.gov (United States)

    Slugocki, Christopher; Bosnyak, Daniel; Trainor, Laurel J

    2017-03-01

    Recent electrophysiological work has evinced a capacity for plasticity in subcortical auditory nuclei in human listeners. Similar plastic effects have been measured in cortically-generated auditory potentials but it is unclear how the two interact. Here we present Simultaneously-Evoked Auditory Potentials (SEAP), a method designed to concurrently elicit electrophysiological brain potentials from inferior colliculus, thalamus, and primary and secondary auditory cortices. Twenty-six normal-hearing adult subjects (mean 19.26 years, 9 male) were exposed to 2400 monaural (right-ear) presentations of a specially-designed stimulus which consisted of a pure-tone carrier (500 or 600 Hz) that had been amplitude-modulated at the sum of 37 and 81 Hz (depth 100%). Presentation followed an oddball paradigm wherein the pure-tone carrier was set to 500 Hz for 85% of presentations and pseudo-randomly changed to 600 Hz for the remaining 15% of presentations. Single-channel electroencephalographic data were recorded from each subject using a vertical montage referenced to the right earlobe. We show that SEAP elicits a 500 Hz frequency-following response (FFR; generated in inferior colliculus), 80 (subcortical) and 40 (primary auditory cortex) Hz auditory steady-state responses (ASSRs), mismatch negativity (MMN) and P3a (when there is an occasional change in carrier frequency; secondary auditory cortex) in addition to the obligatory N1-P2 complex (secondary auditory cortex). Analyses showed that subcortical and cortical processes are linked as (i) the latency of the FFR predicts the phase delay of the 40 Hz steady-state response, (ii) the phase delays of the 40 and 80 Hz steady-state responses are correlated, and (iii) the fidelity of the FFR predicts the latency of the N1 component. The SEAP method offers a new approach for measuring the dynamic encoding of acoustic features at multiple levels of the auditory pathway. As such, SEAP is a promising tool with which to study how

  17. Corrective feedback, learner uptake, and feedback perception in a Chinese as a foreign language classroom

    Directory of Open Access Journals (Sweden)

    Tingfeng Fu

    2016-03-01

    Full Text Available The role of corrective feedback in second language classrooms has received considerable research attention in the past few decades. However, most of this research has been conducted in English-teaching settings, either ESL or EFL. This study examined teacher feedback, learner uptake as well as learner and teacher perception of feedback in an adult Chinese as a foreign language classroom. Ten hours of classroom interactions were videotaped, transcribed and coded for analysis. Lyster and Ranta’s (1997 coding system involving six types of feedback was initially used to identify feedback frequency and learner uptake. However, the teacher was found to use a number of additional feedback types. Altogether, 12 types of feedback were identified: recasts, delayed recasts, clarification requests, translation, metalinguistic feedback, elicitation, explicit correction, asking a direct question, repetition, directing question to other students, re-asks, and using L1-English. Differences were noted in the frequency of some of the feedback types as well as learner uptake compared to what had been reported in some previous ESL and EFL studies. With respect to the new feedback types, some led to noticeable uptake. As for the students’ and teacher’s perceptions, they did not match and both the teacher and the students were generally not accurate in perceiving the frequency of each feedback type. The findings are discussed in terms of the role of context in affecting the provision and effectiveness of feedback and its relationship to student and teacher perception of feedback.

  18. Haptic Foot Feedback for Kicking Training in Virtual Reality

    OpenAIRE

    Huang, Hank; Tan, Hong

    2016-01-01

    As means to further supplement athletic performances increases, virtual reality is becoming helpful to sports in terms of cognitive training such as reaction, mentality, and game strategies. With the aid of haptic feedback, interaction with virtual objects increases by another dimension, in addition to the presence of visual and auditory feedback. This research presents an integrated system of a virtual reality environment, motion tracking system, and a haptic unit designed for the dorsal foo...

  19. Sense of agency over speech and proneness to auditory hallucinations: the reality-monitoring paradigm.

    Science.gov (United States)

    Sugimori, Eriko; Asai, Tomohisa; Tanno, Yoshihiko

    2011-01-01

    This study investigated the effects of imagining speaking aloud, sensorimotor feedback, and auditory feedback on respondents' reports of having spoken aloud and examined the relationship between responses to "spoken aloud" in the reality-monitoring task and the sense of agency over speech. After speaking aloud, lip-synching, or imagining speaking, participants were asked whether each word had actually been spoken. The number of endorsements of "spoken aloud" was higher for words spoken aloud than for those lip-synched and higher for words lip-synched than for those imagined as having been spoken aloud. When participants were prevented by white noise from receiving auditory feedback, the discriminability of words spoken aloud decreased, and when auditory feedback was altered, reports of having spoken aloud decreased even though participants had actually done so. It was also found that those who have had auditory hallucination-like experiences were less able than were those without such experiences to discriminate the words spoken aloud, suggesting that endorsements of having "spoken aloud" in the reality-monitoring task reflected a sense of agency over speech. These results were explained in terms of the source-monitoring framework, and we proposed a revised forward model of speech in order to investigate auditory hallucinations.

  20. Impairments in musical abilities reflected in the auditory brainstem: evidence from congenital amusia.

    Science.gov (United States)

    Lehmann, Alexandre; Skoe, Erika; Moreau, Patricia; Peretz, Isabelle; Kraus, Nina

    2015-07-01

    Congenital amusia is a neurogenetic condition, characterized by a deficit in music perception and production, not explained by hearing loss, brain damage or lack of exposure to music. Despite inferior musical performance, amusics exhibit normal auditory cortical responses, with abnormal neural correlates suggested to lie beyond auditory cortices. Here we show, using auditory brainstem responses to complex sounds in humans, that fine-grained automatic processing of sounds is impoverished in amusia. Compared with matched non-musician controls, spectral amplitude was decreased in amusics for higher harmonic components of the auditory brainstem response. We also found a delayed response to the early transient aspects of the auditory stimulus in amusics. Neural measures of spectral amplitude and response timing correlated with participants' behavioral assessments of music processing. We demonstrate, for the first time, that amusia affects how complex acoustic signals are processed in the auditory brainstem. This neural signature of amusia mirrors what is observed in musicians, such that the aspects of the auditory brainstem responses that are enhanced in musicians are degraded in amusics. By showing that gradients of music abilities are reflected in the auditory brainstem, our findings have implications not only for current models of amusia but also for auditory functioning in general.