Academic literature on the topic 'Bispectra'

A parametric identification procedure is proposed that combines the method of multiple scales and higher-order statistics to efficiently and accurately model nonlinear systems. A theoretical background for the method of multiple scales and higher-order statistics is given. Validation of the procedure is performed through applying it to numerical simulations of two nonlinear systems. The results show how the procedure can successfully characterize the system damping and nonlinearities and determine the corresponding parameters. The procedure is then applied to experimental measurements from two structural systems, a cantilevered beam and a three-beam frame. The results show that quadratic damping should be accounted for in both systems. Moreover, for the three-beam frame, the parametric excitation is much more important than the direct excitation. To show the flexibility of the procedure, numerical simulations of ship motion under parametric excitation are used to determine nonlinear parameters govening the relation between pitch, heave, and roll motions. The results show a high level of agreement between the numerical simulation and the mathematical model with the identified parameters.<br>Master of Science

Techniques which utilise a signal's Higher Order Statistics (HOS) can reveal information about non-Gaussian signals and nonlinearities which cannot be obtained using conventional (second-order) techniques. This information may be useful in speech processing because it may provide clues about how to construct new models of speech production which are better than existing models. There has been a recent surge of interest in the application of HOS techniques to speech processing, but this has been handicapped by a lack of understanding of what the HOS properties of speech signals are. Without this understanding the HOS information which is in speech signals can not be efficiently utilised. This thesis describes an investigation into the use of HOS techniques, in particular the third-order frequency domain measure called the bispectrum, to speech signals. Several issues relating to bispectral speech analysis are addressed, including nonlinearity detection, pitch-synchronous analysis, estimation criteria and stationarity. A flaw is identified in an existing algorithm for detecting quadratic nonlinearities, and a new detector is proposed which has better statistical properties. In addition, a new algorithm is developed for estimating the normalised bispectrum of signals contaminated by transient noise. Finally the tools developed in the study are applied to a specially constructed database of continuant speech sounds. The results are consistent with the hypothesis that speech signals do not exhibit quadratic nonlinearity.

Orientador: Celso Antônio Rodrigues<br>Coorientador: Paulo Sergio Patto dos Santos<br>Banca: Stélio Pacca Loureiro Luna<br>Banca: Antônio José de Araújo Aguiar<br>Banca: Lídia Mitsuko Matsubara<br>Banca: Juan Carlos Duque Moreno<br>Resumo: O estudo teve por objetivo avaliar o índice biespectral e os efeitos hemodinâmicos, respiratórios e hemogasométricos da infusão contínua de propofol associado ou não ao fentanil em bezerros. Foram utilizados oito animais machos entre seis e doze meses de idade, holandeses, com massa corporal média de 123 ± 18 kg. Todos os animais participaram de ambos os grupos, respeitando-se sempre um intervalo mínimo de uma semana entre uma anestesia e outra, os bezerros foram aleatoriamente distribuídos entre os grupos. Os animais foram induzidos à anestesia com propofol na dose de 5 mg/kg; IV, grupo controle (GP) ou propofol 4 mg/kg associado ao fentanil 0,001 mg/kg; IV, grupo fentanil (GF) e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol na taxa de 0,6 mg/kg/minuto; IV, associado ou não à infusão de fentanil 0,001 mg/kg/hora.Em ambos os grupos os fármacos foram administrados por meio de bomba de infusão durante 60 minutos. A mensuração das variáveis hemodinâmicas (FC, PAS, PAD, PAM, DC, PVC, PAPm, PAPOm, IC, IS, IRVS e IRVP), respiratórias (ETCO2, f, SpO2, VTE e VME), hemogasométricas (PaO2, PaCO2, SaO2, DB, pH e HCO3-) e indice bispectral (BIS, IQS e EMG) foi feita antes da indução anestésica (MB), e 15, 30,45 e 60 minutos após o início da infusão contínua dos fármacos (M15, M30, M45 e M60, respectivamente). Os parâmetros hemodinâmicos mantiveram-se estáveis durante o período de avalição, não foram observadas diferenças significativas entre os grupos nas variáveis respiratórias ou no BIS, porém, todos os animais apresentaram depressão respiratória e acidose. Com a infusão de propofol associado ou não ao fentanil obteve-se manutenção satisfatória dos parâmetros hemodinâmicos com depressão respiratória, indicando, portanto, a necessidade do emprego de ventilação...<br>Abstract: The aim of this study was to evaluate the bispectral index and hemodynamic, respiratory and blood gas effects of continuous infusion of propofol with or without fentanyl in calves. Eight animals were used, with six to 12 months old, male Holstein calves, with an average weight of 123 ± 18 kg. All animals participated in both groups, respecting always a minimum interval of one week between the anesthetic procedures, the calves were randomly distributed between groups. They were induced to anesthesia with propofol at a dose of 5 mgkg-1 IV control group (GP) or propofol 4 mg kg-1 associated with fentanyl 0.001mgkg-1 IV fentanyl group (GF) and positioned in right lateral decubitus, where remained spontaneously breathing room air. Subsequently, the Anesthesia was maintained by continuous infusion of propofol at the rate of 0.6 mg kg-1 min-1 IV, with or without the infusion of fentanyl 0.001mg kg-1 hour-1. In both groups, drugs were administered through an infusion pump over 60 minutes. The measurements of hemodynamic parameters (HR, SAP, DAP, MAP, CO, CVP, mPAP, mPAPO, CI, SI, SVRI and PVRI), respiratory (ETCO2, f, SpO2,VME and VTE), blood gas(PaO2, PaCO2, SaO2, DB, pHandHCO3-) and bispectral index (BIS, SQI and EMG) were evaluated before anesthesia induction(MB), 15, 30, 45 and 60 minutes after the beginning of continuous infusion of drugs (M15, M30, M45 and M60, respectively). Hemodynamic parameters remained stable during the evaluate on period, no significant differences were observed between the groups in the respiratory variables and BIS, however, all animals presented respiratory acidosis. With the infusion of propofol associated or not with fentanyl the maintenance of the hemodynamic parameters was satisfactory with respiratory acidosis indicating, therefore, the use of mechanical ventilation<br>Doutor

Made available in DSpace on 2016-07-01T13:10:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-11-06. Added 1 bitstream(s) on 2016-07-01T13:14:17Z : No. of bitstreams: 1 000866936.pdf: 1220294 bytes, checksum: 4c57fe16155fd1456befca08e06dd4e1 (MD5)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>O estudo teve por objetivo avaliar o índice biespectral e os efeitos hemodinâmicos, respiratórios e hemogasométricos da infusão contínua de propofol associado ou não ao fentanil em bezerros. Foram utilizados oito animais machos entre seis e doze meses de idade, holandeses, com massa corporal média de 123 ± 18 kg. Todos os animais participaram de ambos os grupos, respeitando-se sempre um intervalo mínimo de uma semana entre uma anestesia e outra, os bezerros foram aleatoriamente distribuídos entre os grupos. Os animais foram induzidos à anestesia com propofol na dose de 5 mg/kg; IV, grupo controle (GP) ou propofol 4 mg/kg associado ao fentanil 0,001 mg/kg; IV, grupo fentanil (GF) e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol na taxa de 0,6 mg/kg/minuto; IV, associado ou não à infusão de fentanil 0,001 mg/kg/hora.Em ambos os grupos os fármacos foram administrados por meio de bomba de infusão durante 60 minutos. A mensuração das variáveis hemodinâmicas (FC, PAS, PAD, PAM, DC, PVC, PAPm, PAPOm, IC, IS, IRVS e IRVP), respiratórias (ETCO2, f, SpO2, VTE e VME), hemogasométricas (PaO2, PaCO2, SaO2, DB, pH e HCO3-) e indice bispectral (BIS, IQS e EMG) foi feita antes da indução anestésica (MB), e 15, 30,45 e 60 minutos após o início da infusão contínua dos fármacos (M15, M30, M45 e M60, respectivamente). Os parâmetros hemodinâmicos mantiveram-se estáveis durante o período de avalição, não foram observadas diferenças significativas entre os grupos nas variáveis respiratórias ou no BIS, porém, todos os animais apresentaram depressão respiratória e acidose. Com a infusão de propofol associado ou não ao fentanil obteve-se manutenção satisfatória dos parâmetros hemodinâmicos com depressão respiratória, indicando, portanto, a necessidade do emprego de ventilação...<br>The aim of this study was to evaluate the bispectral index and hemodynamic, respiratory and blood gas effects of continuous infusion of propofol with or without fentanyl in calves. Eight animals were used, with six to 12 months old, male Holstein calves, with an average weight of 123 ± 18 kg. All animals participated in both groups, respecting always a minimum interval of one week between the anesthetic procedures, the calves were randomly distributed between groups. They were induced to anesthesia with propofol at a dose of 5 mgkg-1 IV control group (GP) or propofol 4 mg kg-1 associated with fentanyl 0.001mgkg-1 IV fentanyl group (GF) and positioned in right lateral decubitus, where remained spontaneously breathing room air. Subsequently, the Anesthesia was maintained by continuous infusion of propofol at the rate of 0.6 mg kg-1 min-1 IV, with or without the infusion of fentanyl 0.001mg kg-1 hour-1. In both groups, drugs were administered through an infusion pump over 60 minutes. The measurements of hemodynamic parameters (HR, SAP, DAP, MAP, CO, CVP, mPAP, mPAPO, CI, SI, SVRI and PVRI), respiratory (ETCO2, f, SpO2,VME and VTE), blood gas(PaO2, PaCO2, SaO2, DB, pHandHCO3-) and bispectral index (BIS, SQI and EMG) were evaluated before anesthesia induction(MB), 15, 30, 45 and 60 minutes after the beginning of continuous infusion of drugs (M15, M30, M45 and M60, respectively). Hemodynamic parameters remained stable during the evaluate on period, no significant differences were observed between the groups in the respiratory variables and BIS, however, all animals presented respiratory acidosis. With the infusion of propofol associated or not with fentanyl the maintenance of the hemodynamic parameters was satisfactory with respiratory acidosis indicating, therefore, the use of mechanical ventilation<br>FAPESP: 2013/09469-1

Thesis (M.S. in Physics)--Naval Postgraduate School, June 2007.<br>Thesis Advisor(s): Brett Borden. "June 2007." Description based on title screen as viewed on July 31, 2007. Includes bibliographical references (p. 79-80). Also available in print.