Wavelet modeling of priors on triangles

Parameters in statistical problems often live in a geometry of certain shape. For example, count probabilities in a multinomial distribution belong to a simplex. For these problems, Bayesian analysis needs to model priors satisfying certain constraints imposed by the geometry. This paper investigates modeling of priors on triangles by use of wavelets constructed specifically for triangles. Theoretical analysis and numerical simulations show that our modeling is flexible and is superior to the commonly used Dirichlet prior.     

Relationships Between Post-Data Accuracy Measures

In the usual frequentist formulation of testing and interval estimation there is a strong relationship between -level tests and 1 - confidence intervals. Such strong relationships do not always persist for post-data, or Bayesian, measures of accuracy of these procedures. We explore the relationship between post-data measures of accuracy of both tests and interval estimates, measures that are derived under a decision-theoretic structure. We find that, in general, there are strong post-data relationships in the one-sided case, and some relationships in the two-sided case.     

A study of the effect of the loss function on Bayes Estimate,posterior risk and hazard function for Lindley distribution

In this paper, mathematical properties of Lindley distribution via Bayesian approach are derived under different loss functions. These properties include: Bayes Estimators, posterior risks and failure rate function for simulation scheme. Elicitation of hyperparameters is also discussed. A real life application to waiting time data at the bank is also described for the developed procedures (also using WinBUGS). Results are compared on the basis of posterior risk.     

关于MIL—HDBK—781中的保证试验

美国军用标准 MIL— H DBK— 781中的保证试验以其所需的试验时间短而引起可靠性工程界的广泛关注。本文指出这种试验方案存在不合理之处 ,并提出了避免不合理因素的修正方案 ,还从贝叶斯统计角度论证了这种修正方案是有道理的 ,值得实际工作中采用。     

Statistical analysis of stochastic resonance with ergodic diffusion noise

A subthreshold signal is transmitted through a channel and may be detected when some noise--with known structure and proportional to some level--is added to the data. There is an optimal noise level, called stochastic resonance that corresponds to the highest Fisher information in the problem of estimation of the signal. As noise we consider an ergodic diffusion process and the asymptotic is considered as time goes to infinity. We propose consistent estimators of the subthreshold signal and we solve further a problem of hypotheses testing. We also discuss evidence of stochastic resonance for both estimation and hypotheses testing problems via examples.     

Effects of prolonged oral reading on F0, SPL, subglottal pressure and amplitude characteristics of glottal flow waveforms

The effects of prolonged (5x45 minute) reading (vocal loading) on fundamental frequency (F0), sound pressure level (SPL), subglottal (intraroral) pressure (p), and two glottal flow waveform parameters (AC amplitude of glottal flow, f, and negative peak amplitude of differentiated flow (d) of normal female and male subjects (N = 80) were studied. Two rest (morning and noon) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustic pressure waveforms of speaking voice samples. The analyses were based on measurement and inverse filtering of the first stressed syllable of "paappa" words repeated 3x5 times for normal, as soft as possible, and as loud as possible phonation. In normal phonation the parameter values changed statistically significantly due to loading. In many cases the values obtained in the morning samples changed after the first loading session. This is interpreted as a vocal "warming-up effect." Especially in soft phonation p, d, and f were sensitive indicators of vocal loading. In both normal and soft phonation, the SPL, p, d, and f values tended to rise due to prolonged reading in the morning and afternoon samples, indicating increased effort (normal phonation) and a rise in the phonatory threshold (soft phonation). The lunch break vocal rest ("rest effect") considerably affected the parameter values in many cases.     

The Activity Patterns of Neck Muscles in Professional Classical Singing

The study aimed to characterize the activity patterns of neck muscles during classical singing. Muscle usage during inhalation and phonation and the relationship to changes in pitch and vocal loudness was of particular interest. Five professional opera singers (2 males, 3 females) participated. Surface electromyographic activity (EMG) was recorded from the upper trapezius (TR), the sternocleidomastoideus (STM), and the scalenus (SC) muscles and the muscles in the posterior neck region (PN). EMG activity in TR and STM was lowered by EMG biofeedback (BF), and the possible effect of lowered EMG activity in these muscles on the EMG activity of SC and PN was analyzed. A strain gauge sensor recorded the chest circumference of the thorax. Three singing tasks were performed. Each task was performed three times with variation in vocal loudness and pitch. After the first performance of the singing tasks, the BF session was carried out. Thereafter muscle activity was recorded in repeat performances of the same tasks, and the EMG amplitude of all muscles was compared before and after BF. We conclude that STM and SC showed correlated activity patterns during inhalation and phonation by classical singers. Second, substantial muscle activity was observed in PN during inhalation and phonation. BF performed on TR and STM had a secondary effect of lowering EMG activity in SC and PN. The activity of all neck muscles was markedly elevated when singing in the highest pitch. There was no consistent task-based difference in EMG amplitude for the other singing tasks.