A chemometric method and a computer programme are presented for an automatic recognition of (isotope) peak patterns in low resolution mass spectra. Similarity between a theoretical peak pattern (peak heights x i) and ...
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A chemometric method and a computer programme are presented for an automatic recognition of (isotope) peak patterns in low resolution mass spectra. Similarity between a theoretical peak pattern (peak heights x i) and a measured peak pattern (peak heights y i) is defined by the “logarithmic pattern correlation” LPC=?1g (1?r); r is the correlation coefficient for a linear regression y=k·x of the peak heights. Frequency distribution curves for LPC are calculated for different isotope peak patterns by a numerical simulation of experimental errors. From this data threshold values for LPC are derived defining confidence intervals (95% probabillity) for correct recognitions of peak patterns. Application of the method is shown for the interpretation of mass spectra from polychlorinated compounds which were recorded by GC/MS.
Perfused Chara cells were used to measure the rapid-light-induced potential change (rapid LPC) caused by activation of a K+ channel in the plasma membrane through photosynthesis in the presence of various photosynthet...
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Perfused Chara cells were used to measure the rapid-light-induced potential change (rapid LPC) caused by activation of a K+ channel in the plasma membrane through photosynthesis in the presence of various photosynthetic inhibitors. The rapid LPC was inhibited by DCMU [diuron] but recovered on addition of phenazinemethosulfate (PMS) in the presence of DCMU. Carbonylcyanide m-chlorophenylhydrazone (CCCP) stimulated the rapid LPC. DCCD [dicyclohexylcarbodiimide] partially inhibited the rapid LPC with a partial inhibition of oxygen evolution. It is concluded that both cyclic and noncyclic electron flows are coupled with the rapid LPC. To understand the mechanism of K+ channel activation by photosynthetic electron flow, the rapid LPC was measured under continuous internal perfusion. It was suggested that a diffusible substance was not released from chloroplasts, since vigorous continuous perfusion did not inhibit the rapid LPC. The suggestion that the rapid LPC is caused by changes in surface charge density of chloroplasts was supported by the fact that the rapid LPC was inhibited by increasing the ionic strength of the perfusion medium.
Infusion of lysolecithin (LPC; e.g. 88 μg/ml for 0.5–1.0 min) did not significantly impair the vasopressor action of norepinephrine (NE), prostaglandin F2α (PGF2α) and extract of posterior pituitary (EPP) in the i...
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Infusion of lysolecithin (LPC; e.g. 88 μg/ml for 0.5–1.0 min) did not significantly impair the vasopressor action of norepinephrine (NE), prostaglandin F2α (PGF2α) and extract of posterior pituitary (EPP) in the isolated perfused hind legs of rats. In other words, vascular smooth muscle behaves differently from the smooth muscle of the guinea-pig small intestine, since, in the latter, contractions evoked by acetylcholine, prostaglandins etc., are inhibited by LPC. Triton X 100 which, by comparison, was used as a detergent effective on the guinea-pig small intestine, depressed the vasopressor effect of NE, PGF2α and EPP.
This paper describes a computer-based software prototype tool for visualisation of the vocal-tract, during speech articulation, by means of a mid-sagittal view of the human head. The vocal tract graphics are generated...
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ISBN:
(纸本)9789898111180
This paper describes a computer-based software prototype tool for visualisation of the vocal-tract, during speech articulation, by means of a mid-sagittal view of the human head. The vocal tract graphics are generated by estimating both the area functions and the formant frequencies from the acoustic speech signal. First, it is assumed that the speech production process is an autoregressive model. Using a linearprediction analysis, the vocal tract area functions and the first three formants are estimated. The estimated area functions are then mapped to corresponding mid-sagittal distances and displayed as 2D vocal tract lateral graphics. The mapping process is based on a simple numerical algorithm and an accurate reference grid derived from x-rays for the pronunciation of a number English vowels uttered by different speakers. To compensate for possible errors in the estimated area functions due to variation in vocal tract length between speakers, the first two sectional distances are determined by the three formants. Experimental results show high correlation with x-ray data and the PARAFAC analysis. The tool also displays other speech parameters that are closely related to the production of intelligible speech and hence would be useful as a visual feedback aid for speech training of hearing-impaired individuals.
Total laryngectomy is often the treatment of choice for many patients suffering from laryngeal cancer. This procedure alters the speech production mechanism, and tracheoesophageal (TE) speech is an alternative where t...
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ISBN:
(纸本)9781424414833
Total laryngectomy is often the treatment of choice for many patients suffering from laryngeal cancer. This procedure alters the speech production mechanism, and tracheoesophageal (TE) speech is an alternative where the pulmonary air is forced through the esophagus. TE speech is often characterized by poor intelligibility and voice quality. Acoustic analysis of TE speech has the potential of quantifying the voice quality and assisting the speech pathologist in determining and monitoring the therapy process. In this paper, we apply two different methods for predicting the voice quality ratings of TE speakers by naive listeners: (a) conventional spectral and linearprediction measurements that were investigated in earlier studies, and (b) a methodology based on a perceptual auditory model that attempts to mimic the speech quality perception by a normal hearing listener. Experimental results with a database of 35 TE speakers showed that the auditory-model based approach significantly outperforms the traditional methods.
MELP (Mixed Excitation linearprediction) is the improvement of LPC (linear Predictive coding). This is to overcome some of the limitations of LPC. It is one of speech compression and decompression algorithm. The Fede...
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ISBN:
(纸本)9781538632437
MELP (Mixed Excitation linearprediction) is the improvement of LPC (linear Predictive coding). This is to overcome some of the limitations of LPC. It is one of speech compression and decompression algorithm. The Federal standard MELP speech coder is known to provide a good quality decoded speech. The MELP Vocoder decoding part is implemented on ZYNQ-7 ZC706 using Vivado HLS and synthesized the same using the Vivado. The results of Vivado HLS and Vivado are compared.
Evoked potentials and performance of 19 learning-disordered (LD) and 19 normally achieving children were studied in two versions of the Continuous Performance Test (CPT). In both CPT procedures, LD children made more ...
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Evoked potentials and performance of 19 learning-disordered (LD) and 19 normally achieving children were studied in two versions of the Continuous Performance Test (CPT). In both CPT procedures, LD children made more errors of omission and commission than did normal children. Evoked potential differences between groups were especially prominent in the more difficult BX version of the CPT. LD children displayed significantly smaller late positive components (LPC) of the evoked potential to critical stimuli in the task. There were no LPC differences between diagnostic groups for noncritical stimulus categories. The results suggest a deficit in behavioral and cortical indices of sustained attention among LD children.
The purpose of this paper is to improve state estimation in the event of data loss by augmenting a novel Moving Average Autoregressive-based artificial measurement vector with Kalman filtering. The proposed technique ...
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ISBN:
(纸本)9781538635674
The purpose of this paper is to improve state estimation in the event of data loss by augmenting a novel Moving Average Autoregressive-based artificial measurement vector with Kalman filtering. The proposed technique replaces the existing Autoregressive-series based model embedded in the linearprediction techniques through Moving Average Autoregressive-based model. The Autoregressive scheme needs only one type of linearprediction coefficient to be tracked, while the proposed scheme computes two parameters at each recursion. Since Autoregressive Moving Average technique possesses more information, hence it efficiently predicts the future values of a signal. This value is placed as an alternative in the structure (or steps) involved in standard process of state estimations. The ultimate consequences of this extra computations involve more computational efforts. A standard mass-spring damper case study has been provided to show some aspects of the existing and proposed techniques.
The objective of this study is to propose a laboratory test method for confirming LPC (large particle count) reduction by porous membrane filters, which are generally thought to have higher particle removal performanc...
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ISBN:
(纸本)9781479955565
The objective of this study is to propose a laboratory test method for confirming LPC (large particle count) reduction by porous membrane filters, which are generally thought to have higher particle removal performance than melt-blown filters. CMP slurries were filtered by porous membrane filters and a nonwoven depth filter. Then LPC reduction of the filtrates was estimated by a particle counter in conjunction with control membrane test, in which pressure drop increase of a filter (a control membrane) was an indicator of LPC. Difference of LPC for filtrates from each type of filter was small by the particle counter and significant by the control membrane method, but with the porous membrane filter exhibiting lower LPC by the both methods. The results demonstrate that a combination of particle counter and control membrane method can reveal difference of filter performance in LPC reduction with confidence. Further, to show pressure drop increase could be an indicator of LPC, pressure drop increase of the control membrane enhanced by large particles was examined.
A novel algorithm for the segmentation of dysarthric speech into silence, unvoiced and voiced (SUV) segments is presented. The proposed algorithm is based on the combination of short-time energy (STE), zero-crossing r...
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ISBN:
(纸本)9781728161365
A novel algorithm for the segmentation of dysarthric speech into silence, unvoiced and voiced (SUV) segments is presented. The proposed algorithm is based on the combination of short-time energy (STE), zero-crossing rate (ZCR) and linearprediction error variance (LPEV) or the segmentation problem. Extending the previous work in this field, the proposed method will address the difficulties in distinguishing between voiced and unvoiced segments in dysarthric speech. More precisely, the error variance of the linearprediction coefficients will be used to design a three-fold decision matrix that can accommodate the high variability in loudness experienced in dysarthric speech. In addition, a moving average threshold approach will be proposed in order to provide an "as-fit" segmentation technique that is fully automated and that will be able to handle highly severe dysarthric speech with varying loudness and ZCRs. The ability of the proposed fully-automated algorithm will be validated using real speech samples from healthy speakers, and speakers with ataxic dysarthria. The results of the proposed approach are compared with known methods using STE and ZCR. It is observed that the proposed classification method does not only show an improvement in segmentation performance but also provides consistent results in low signal energy situations.
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