generalized beta prior models on fraction defective in reliability test planning in many reliability analyses the probability of obtaining a defective unit in a production process should not be considered constant even though the process is stable and in control engineering experience or previous data of similar or related products may often be used in the proper selection of a prior model to describe the random fluctuations in the fraction defective a generalized beta family of priors several maximum entropy priors and other prior models are considered for this purpose in order to determine the acceptability of a product based on the lifelengths of some test units failure censored reliability sampling plans for location scale distributions using average producer and consumer risks are designed our procedure allows the practitioners to incorporate a restricted parameter space into the reliability analysis and it is reasonably insensitive to small disturbances in the prior information impartial priors are used to reflect prior neutrality between the producer and the consumer when a consensus on the elicited prior model is required nonetheless our approach also enables the producer and the consumer to assume their own prior distributions the use of substantial prior information can in many cases significantly reduce the amount of testing required however the main advantage of utilizing a prior model for the fraction defective is not necessarily reduced sample size but improved assessment of the true sampling risks an example involving shifted exponential lifetimes is considered to illustrate the results

multiple bursts multiple looks and stream coherence in the release from informational masking in the simultaneous multitone masking paradigm introduced by neff and green percept psychophys 41 409 415 1987 the masker typically is a small number of tones having frequencies and levels that are randomly drawn on every presentation large amounts of masking for a pure tone signal often occur that are thought to reflect central rather than peripheral limitations on processing previous work from this laboratory has indicated that playing a rapid succession of randomly drawn multitone maskers in each observation interval dramatically reduces the amount of masking that is observed relative to a single burst sb in this multiple bursts different mbd procedure the signal tone is the only constant frequency component during the sequence of bursts and tends to perceptually segregate from the masker in this study the number of masker bursts and the interburst interval ibi were varied the goals were to determine how the release from masking relative to the sb condition depends on the number of bursts and to examine whether increasing the ibi would cause each burst to be processed independently if the latter were true it might disrupt the perception of signal stream coherence thereby diminishing the mbd advantage however multiple independent looks could also lead to an improvement in performance for those subjects showing large amounts of informational masking in the sb condition substantial reduction in masked thresholds occurred as the number of masker bursts increased while masking increased as ibi lengthened the results were not consistent with a simple version of a multiple look model in which the information from each burst was combined optimally but instead appear to be attributable to mechanisms involved in the perceptual organization of sounds

the influence of age and high frequency hearing loss on sensitivity to temporal fine structure at low frequencies l sensitivity to temporal fine structure tfs at low frequencies may be adversely affected by hearing loss at high frequencies even when absolute thresholds at low frequencies are within the normal range however in several studies suggesting this the effects of hearing loss and age were confounded here interaural phase discrimination ipd thresholds for pure tones at 500 and 750 hz were measured for 39 subjects with ages from 61 to 83 yr all subjects had near normal audiometric thresholds at low frequencies but thresholds varied across subjects at high frequencies ipd thresholds were correlated with age ipd thresholds for the test frequency of 750 hz were weakly correlated with absolute thresholds at high frequencies but these correlations became non significant when the effect of age was partialed out the results do not confirm that sensitivity to tfs at low frequencies is influenced by hearing loss at high frequencies independently of age

the effect of spatial separation on informational and energetic masking of speech the effect of spatial separation of sources on the masking of a speech signal was investigated for three types of maskers ranging from energetic to informational normal hearing listeners performed a closed set speech identification task in the presence of a masker at various signal to noise ratios stimuli were presented in a quiet sound field the signal was played from 0 azimuth and a masker was played either from the same location or from 90 to the right signals and maskers were derived from sentences that were preprocessed by a modified cochlear implant simulation program that filtered each sentence into 15 frequency bands extracted the envelopes from each band and used these envelopes to modulate pure tones at the center frequencies of the bands in each trial the signal was generated by summing together eight randomly selected frequency bands from the preprocessed signal sentence three maskers were derived from the preprocessed masker sentences 1 different band sentence which was generated by summing together six randomly selected frequency bands out of the seven bands not present in the signal resulting in primarily informational masking 2 different band noise which was generated by convolving the different band sentence with gaussian noise and 3 same band noise which was generated by summing the same eight bands from the preprocessed masker sentence that were used in the signal sentence and convolving the result with gaussian noise resulting in primarily energetic masking results revealed that in the different band sentence masker the effect of spatial separation averaged 18 db at 51 correct while in the different band and same band noise maskers the effect was less than 10 db these results suggest that in these conditions the advantage due to spatial separation of sources is greater for informational masking than for energetic masking

contribution of harmonicity and location to auditory object formation in free field evidence from event related brain potentials the contribution of location and harmonicity cues in sound segregation was investigated using behavioral reports and source waveforms derived from the scalp recorded evoked potentials participants were presented with sounds composed of multiple harmonics in a free field environment the third harmonic was either tuned or mistuned and could be presented from the same or different location from the remaining harmonics presenting the third harmonic at a different location than the remaining harmonics increased the likelihood of hearing the tuned or slightly i e 2 mistuned harmonic as a separate object partials mistuned by 16 of their original value pop out of the complex and were paralleled by an object related negativity orn that superimposed the n1 and p2 components for the 2 mistuned stimuli the orn was present only when the mistuned harmonic was presented at a different location than the remaining harmonics presenting the tuned harmonic at a different location also yielded changes in neural activity between 150 and 250 ms after sound onset the behavioral and electrophysiological results indicate that listeners can segregate sounds based on harmonicity or location alone the results also indicate that a conjunction of harmonicity and location cues contribute to sound segregation primarily when harmonicity is ambiguous

the effect of tone vocoding on spatial release from masking for old hearing impaired listeners old hearing impaired listeners generally benefit little from lateral separation of multiple talkers when listening to one of them this study aimed to determine how spatial release from masking srm in such listeners is affected when the interaural time differences itds in the temporal fine structure tfs are manipulated by tone vocoding tvc at the ears by a master hearing aid system word recall was compared with and without tvc when target and masker sentences from a closed set were played simultaneously from the front loudspeaker co located and when the maskers were played 45 to the left and right of the listener separated for 20 hearing impaired listeners aged 64 to 86 srm was 3 7 db smaller with tvc than without tvc this difference in srm correlated with mean audiometric thresholds below 1 5 khz even when monaural tfs sensitivity discrimination of frequency shifts in identically filtered complexes was partialed out suggesting that low frequency audiometric thresholds may be a good indicator of candidacy for hearing aids that preserve itds the tvc difference in srm was not correlated with age pure tone itd thresholds nor fundamental frequency difference limens and only with monaural tfs sensitivity before control for low frequency audiometric thresholds

a 3 local characterization of u6 2 and fi22 abstract the unitary group u6 2 often referred to as fi21 and the sporadic simple group fi22 discovered by fischer b fischer finite groups generated by 3 transpositions i invent math 13 1971 232 246 6 are characterized by specifying partial information about the structure of the normalizer of a non trivial 3 central cyclic subgroup

a 3 local characterization of co2 abstract conway s second largest simple group co2 is characterized by the centralizer of an element of order 3 and certain fusion data

predicting binaural speech intelligibility using the signal to noise ratio in the envelope power spectrum domain this study proposes a binaural extension to the multi resolution speech based envelope power spectrum model mr sepsm jorgensen ewert and dau 2013 j acoust soc am 134 436 446 it consists of a combination of better ear be and binaural unmasking processes implemented as two monaural realizations of the mr sepsm combined with a short term equalization cancellation process and uses the signal to noise ratio in the envelope domain snrenv as the decision metric the model requires only two parameters to be fitted per speech material and does not require an explicit frequency weighting the model was validated against three data sets from the literature which covered the following effects the number of maskers the masker types speech shaped noise ssn speech modulated ssn babble and reversed speech the masker s azimuths reverberation on the target and masker and the interaural time difference of the target and masker the pearson correlation coefficient between the simulated spee

speech intelligibility as a function of the number of channels of stimulation for signal processors using sine wave and noise band outputs vowels consonants and sentences were processed through software emulations of cochlear implant signal processors with 2 9 output channels the signals were then presented as either the sum of sine waves at the center of the channels or as the sum of noise bands the width of the channels to normal hearing listeners for identification the results indicate as previous investigations have suggested that high levels of speech understanding can be obtained using signal processors with a small number of channels the number of channels needed for high levels of performance varied with the nature of the test material for the most difficult material vowels produced by men women and girls no statistically significant differences in performance were observed when the number of channels was increased beyond 8 for the least difficult material sentences no statistically significant differences in performance were observed when the number of channels was increased beyond 5 the nature of the output signal noise bands or sine waves made only a small difference in performance the mechanism mediating the high levels of speech recognition achieved with only few channels of stimulation may be the same one that mediates the recognition of signals produced by speakers with a high fundamental frequency i e the levels of adjacent channels are used to determine the frequency of the input signal the results of an experiment in which frequency information was altered but temporal information was not altered indicates that vowel recognition is based on information in the frequency domain even when the number of channels of stimulation is small

the effect of spatial separation in distance on the intelligibility of speech in rooms the influence of spatial separation in source distance on speech reception thresholds srts is investigated in one scenario the target was presented at 0 5 m distance and the masker varied from 0 5 m distance up to 10 m in a second scenario the masker was presented at 0 5 m distance and the target distance varied the stimuli were synthesized using convolution with binaural room impulse responses brirs measured on a dummy head in a reverberant auditorium and were equalized to compensate for distance dependent spectral and intensity changes all sources were simulated directly in front of the listener srts decreased monotonically when the target was at 0 5 m and the speech masker was moved further away resulting in a srt improvement of up to 10 db when the speech masker was at 0 5 m and the target was moved away a large variation across subjects was observed neither short term signal to noise ratio snr improvements nor cross ear glimpsing could account for the observed improvement in intelligibility however the effect might be explained by an improvement in the snr in the modulation domain and a decrease in informational masking this study demonstrates that distance related cues can play a significant role when listening in complex environments

assessing the lifetime performance index of rayleigh products based on the bayesian estimation under progressive type ii right censored samples abstract lifetime performance assessment is important in service or manufacturing industries hence lifetime performance index c l is used to measure the potential and performance of a process where l is the lower specification limit in this paper assuming the conjugate prior distribution and squared error loss function this study constructs a bayes estimator under the rayleigh distribution with the progressive type ii right censored sample the bayes estimator of c l is then utilized to develop a credible interval in the condition of known l moreover we also propose a bayesian test to assess the lifetime performance of products finally we give two examples and the monte carlo simulation to assess the behavior of the lifetime performance index c l moreover the purchasers can then employ the credible interval and the bayesian test to determine whether the product performance adheres to the required level

informational masking for simultaneous nonspeech stimuli psychometric functions for fixed and randomly mixed maskers sensitivity d and response bias were measured as a function of target level for the detection of a 1000 hz tone in multitone maskers using a one interval two alternative forced choice 1i 2afc paradigm ten such maskers each with eight randomly selected components in the region 200 5000 hz with 800 1250 hz excluded to form a protected zone were presented under two conditions the fixed condition in which the same eight component masker is used throughout an experimental run and the random condition in which an eight component masker is chosen randomly trial to trial from the given set of ten such maskers differences between the results obtained with these two conditions help characterize the listener s susceptibility to informational masking im the d results show great intersubject variability but can be reasonably well fit by simple energy detector models in which internal noise and filter bandwidth are used as fitting parameters in contrast the results are not well fit by these models in addition to presentation of new data and its relation to energy detector models this paper provides comments on a variety of issues problems and research needs in the im area 2005 acoustical society of america doi 10 1121 1 2032748

a density quantile function approach to optimal spacing selection in this paper design techniques for continuous parameter time series regression analysis are employed to develop a general approach to optimal spacing selection for the linear estimation of location and scale parameters by sample quantiles from uncensored or censored samples the spacings derived from this approach are asymptotically optimal in the sense that they result in near optimal asymptotic relative efficiencies for large values of k the number of spacing elements a comparison with the optimum efficiencies for several distribution types indicates that the asymptotically optimum spacings perform well for k 7 the regression framework is also utilized to develop sufficient conditions for optimal spacing unicity and to obtain asymptotically optimal spacings for quantile estimation

relations between frequency selectivity temporal fine structure processing and speech reception in impaired hearing frequency selectivity temporal fine structure tfs processing and speech reception were assessed for six normal hearing nh listeners ten sensorineurally hearing impaired hi listeners with similar high frequency losses and two listeners with an obscure dysfunction od tfs processing was investigated at low frequencies in regions of normal hearing through measurements of binaural masked detection tone lateralization and monaural frequency modulation fm detection lateralization and fm detection thresholds were measured in quiet and in background noise speech reception thresholds were obtained for full spectrum and lowpass filtered sentences with different interferers both the hi listeners and the od listeners showed poorer performance than the nh listeners in terms of frequency selectivity tfs processing and speech reception while a correlation was observed between the monaural and binaural tfs processing deficits in the hi listeners no relation was found between tfs processing and frequency selectivity the effect of noise on tfs processing was not larger for the hi listeners than for the nh listeners finally tfs processing performance was correlated with speech reception in a two talker background and lateralized noise but not in amplitude modulated noise the results provide constraints for future models of impaired auditory signal processing

computing optimal confidence sets for pareto models under progressive censoring this paper presents two families of joint confidence sets for the pareto shape and precision parameters based on progressively censored data which include the existing regions in the literature as particular cases and derives explicit expressions for the corresponding areas upon using fiducial arguments an exact and quick computational method is then proposed in order to find the smallest area pareto region which depends on the minimal sufficient statistic with a specified confidence level shortest length confidence intervals for the pareto parameters are also provided the reduction in area of the minimal joint confidence region with respect to the existing sets is substantial in most situations and impressive in some cases for illustrative and comparative purposes two practical studies concerning device lifetimes and business failures are considered applications of the smallest confidence sets include uses in hypothesis testing and estimation in particular it is possible to construct confidence intervals for functions of the pareto parameters as well as pointwise and simultaneous confidence bands for the pareto reliability function

speech localization in a multitalker mixture an experiment was performed that measured for the frontal audio visual horizon how accurately listeners could localize a female voice target amidst four spatially distributed male voice maskers to examine whether listeners can make use of a priori knowledge about the configuration of the sources performance was examined in two conditions either the masker locations were fixed in one of five known patterns or the locations varied from trial to trial the presence of maskers disrupted speech localization even after accounting for reduced target detectability averaged across all target locations the rms error in responses decreased by 20 when a priori knowledge about masker locations was available the effect was even stronger for the target locations that did not coincide with the maskers error reduction of 36 while no change in errors was observed for targets coinciding with maskers the benefits were reduced when the target to masker intensity ratio was increased or when the maskers were in a pattern that made it difficult to make use of the a priori information the results confirm that localization in speech mixtures is modified by the listener s expectations about the spatial arrangement of the sources

kalman state filtering based least squares iterative parameter estimation for observer canonical state space systems using decomposition this paper focuses on the parameter and state estimation problems for observer canonical state space systems from measurement information derives a kalman filter based least squares iterative kf lsi algorithm to estimate the parameters and states and a model decomposition based kf lsi algorithm to enhance computational efficiency an example is provided to confirm the effectiveness of the proposed algorithms

similarity uncertainty and masking in the identification of nonspeech auditory patterns this study examined whether increasing the similarity between informational maskers and signals would increase the amount of masking obtained in a nonspeech pattern identification task the signals were contiguous sequences of pure tone bursts arranged in six narrow band spectro temporal patterns the informational maskers were sequences of multitone bursts played synchronously with the signal tones the listener s task was to identify the patterns in a 1 interval 6 alternative forced choice procedure three types of multitone maskers were generated according to different randomization rules for the least signal like informational masker the components in each multitone burst were chosen at random within the frequency range of 200 6500 hz excluding a protected region around the signal frequencies for the intermediate masker the frequency components in the first burst were chosen quasirandomly but the components in successive bursts were constrained to fall in narrow frequency bands around the frequencies of the components in the initial burst within the narrow bands the frequencies were randomized this masker was considered to be more similar to the signal patterns because it consisted of a set of narrow band sequences any one of which might be mistaken for a signal pattern the most signal like masker was similar to the intermediate masker in that it consisted of a set of synchronously played narrow band sequences but the variation in frequency within each sequence was sinusoidal completing roughly one period in a sequence this masker consisted of discernible patterns but not patterns that were part of the set of signals in addition masking produced by gaussian noise bursts thought to produce primarily peripherally based energetic masking was measured and compared to the informational masking results for the three informational maskers more masking was produced by the maskers comprised of narrow band sequences than for the masker in which the frequencies were not constrained to narrow bands also the slopes of the performance level functions for the three informational maskers were much shallower than for the gaussian noise masker or for no masker the findings provided qualified support for the hypothesis that increasing the similarity between signals and maskers or parts of the maskers causes greater informational masking however it is also possible that the greater masking was a consequence of increasing the number of perceptual streams that had to be evaluated by the listener

the effect of interaural delay of the masker on masking level differences in young and old adults diotic sono thresholds and dichotic s pi n pi tau thresholds were measured for young and old adults using a 500 hz pure tone signal and broadband burst masking noise at 37 db spl hz in the dichotic condition both the signal and the masker were phase reversed and the masker was presented with an interaural delay of 0 25 0 5 0 75 1 1 25 1 5 1 75 2 3 or 5 ms masking level differences mlds were determined by subtracting dichotic thresholds from diotic thresholds the sono thresholds for the old subjects did not differ significantly from those for the young subjects however when mlds were plotted as a function of delay the pattern of results differed significantly between young and old subjects this difference in pattern was completely accounted for in terms of a delay line version of durlach s equalization and cancellation ec model n i durlach in foundations of modern auditory theory edited by j v tobias academic new york 1972 b a schneider and p m zurek j acoust soc am 86 1756 1763 1989 by assuming that temporal jitter increases with internal delay in young subjects but that it does not vary with the amount of internal delay in old subjects

the effect of better ear glimpsing on spatial release from masking the current experiment investigated whether better ear glimpsing can explain the spatial release achieved by normal hearing adults when situations are high in informational masking both modeling and behavioral methods were used the speech reception thresholds of 38 young adults were measured for co located spatially separated and two better ear glimpsed conditions in the better ear glimpsed conditions the binaural signals were processed so that in each time frequency segment the signal with the better snr left or right ear was presented diotically to investigate the effect of widening auditory filters on better ear glimpsing adjacent frequency bands were combined in one of the better ear glimpsing conditions twenty two participants were tested with maskers high in informational masking while 16 participants were tested with maskers lower in informational masking the mean speech reception thresholds achieved in the glimpsed conditions were significantly worse than in the spatially separated condition this suggests that better ear glimpsing can explain some but not all of the observed spatial release from masking the difference between performance in the spatially separated and glimpsed conditions was largest when informational masking was high suggesting better ear glimpsing may release energetic rather than informational masking reducing the number of frequency bands sampled had a small effect on performance

masking of speech by amplitude modulated noise abstract the degree of masking of human speech by environmental noise may be influenced by amplitude variations in the noise the listener s condition with respect to age and auditory function may affect his sensitivity to such noise also fatigue effects are possible after prolonged exposure to masking noise these aspects have been tested in the present study the results show that in general amplitude modulation of a masking noise reduces its speech masking effect as compared to unmodulated noise of the same r m s sound level and spectrum age did not affect the release of masking found in am noise however hearing impaired listeners obtained much less release of speech masking than those with normal hearing small but statistically significant fatigue effects were found after up to 60 min exposure to noise at 60 db spl the speech to noise ratio needed for 30 correct speech recognition was significantly affected by both age and hearing loss

estimating the lifetime performance index with weibull distribution based on progressive first failure censoring scheme an important topic in the manufacturing industries is the assessing of the lifetime performance in this paper it is supposed the lifetimes of products are independent and have a common weibull distribution with a known shape parameter the lifetime performance index c l proposed by montgomery 1985 1 is used for evaluating the performance of a process with respect to a lower specification limit l the maximum likelihood estimate of c l is obtained on the basis of the progressive first failure censored data this estimate is then used for developing a confidence interval for c l the behavior of the confidence interval for the parameter c l given a significance level is investigated and also two illustrative examples and a sensitivity analysis are given for the exponential distribution as a special case of weibull distribution a comparison study for various estimates of c l based on mean squared error mse and pitman measure of closeness pmc criteria is done

assessing the lifetime performance index of products with the exponential distribution under progressively type ii right censored samples in practice lifetime performance index c l is used to measure the potential and performance of a process where l is the lower specification limit progressive censoring scheme is quite useful in many practical situations where budget constraints are in place or there is a demand for rapid testing in this paper under the assumption of exponential distribution this study constructs a maximum likelihood estimator mle of c l based on the progressively type ii right censored sample the mle of c l is then utilized to develop the hypothesis testing procedure in the condition of known l the new testing procedure can be employed by product managers to assess whether the lifetime of products or items adheres to the required level in the condition of known l finally we give one example to illustrate the use of the testing algorithmic procedure under given significance level

binaural advantage for sound pattern identification listeners learned to identify six tone patterns in continuous broadband noise the patterns consisted of eight sequential 48 ms tones having frequencies that were 1 constant 2 rising 3 falling 4 alternating 5 one step up or 6 one step down the frequency extent was 14 of the nominal center frequency masking level differences mlds were measured in a 2i2afc adaptive detection task by comparing thresholds for noso and nos conditions identification level differences ilds were measured in a 1i6afc fixed level identification task by comparing the psychometric functions for the two interaural conditions two center frequencies 500 and 3000 hz were used in addition for ilds the center frequency was randomly roved over the 2500 hz range average mlds and ilds were 12 db at 500 hz and 3 db at 3000 hz however in the roved condition the psychometric function for the nos condition was much shallower than for the noso condition so ilds decreased with increasing s n level this result is in good agreement with similar findings for speech h levitt and l r rabiner j acoust soc am 42 601 608 1967 the orderly relationship between detection and identification breaks down in certain conditions when an informational masker is used work supported by nih nindcd

binaural speech intelligibility in noise for hearing impaired listeners the effect of head induced interaural time delay itd and interaural level differences ild on binaural speech intelligibility in noise was studied for listeners with symmetrical and asymmetrical sensorineural hearing losses the material recorded with a kemar manikin in an anechoic room consisted of speech presented from the front 0 and noise presented at azimuths of 0 30 and 90 derived noise signals containing either only itd or only ild were generated using a computer for both groups of subjects speech reception thresholds srt for sentences in noise were determined as a function of 1 noise azimuth 2 binaural cue and 3 an interaural difference in overall presentation level simulating the effect of a monaural hearing aid comparison of the mean results with corresponding data obtained previously from normal hearing listeners shows that the hearing impaired have a 2 5 db higher srt in noise when both speech and noise are presented from the front and 2 6 5 1 db less binaural gain when the noise azimuth is changed from 0 to 90 the gain due to ild varies among the hearing impaired listeners between o db and normal values of 7 db or more it depends on the high frequency hearing loss at the side presented with the most favorable signal to noise s n ratio the gain due to itd is nearly normal for the symmetrically impaired 4 2 db compared with 4 7 db for the normal hearing but only 2 5 db in the case of asymmetrical impairment when itd is introduced in noise already containing ild the resulting gain is 2 2 5 db for all groups the only marked effect of the interaural difference in overall presentation level is a reduction of the gain due to ild when the level at the ear with the better s n ratio is decreased this implies that an optimal monaural hearing aid with a moderate gain will hardly interfere with unmasking through itd while it may increase the gain due to ild by preventing or diminishing threshold effects

the extent to which a position based explanation accounts for binaural release from informational masking detection was measured for a 500hz tone masked by noise an energetic masker or sets of ten randomly drawn tones an informational masker presenting the maskers diotically and the target tone with a variety of interaural differences interaural amplitude ratios and or interaural time delays resulted in reduced detection thresholds relative to when the target was presented diotically binaural release from masking thresholds observed when time and amplitude differences applied to the target were reinforcing favored the same ear resulting in a lateralized position for the target were not significantly different from thresholds obtained when differences were opposing favored opposite ears resulting in a centered position for the target this irrelevance of differences in the perceived location of the target is a classic result for energetic maskers but had not previously been shown for informational maskers however this parallellism between the patterns of binaural release for energet

a 3 local identification of two almost simple extensions of pω8 2 abstract we provide 3 local characterizations of the almost simple groups p 8 2 3 and p 8 2 sym 3 both groups are examples of groups of parabolic characteristic three and we identify them from the structure of the centralizer of an element of order three

spatial release from masking as a function of the spectral overlap of competing talkers this study tested the hypothesis that the reduced spatial release from speech on speech masking typically observed in listeners with sensorineural hearing loss results from increased energetic masking target sentences were presented simultaneously with a speech masker and the spectral overlap between the pair and hence the energetic masking was systematically varied the results are consistent with increased energetic masking in listeners with hearing loss that limits performance when listening in speech mixtures however listeners with hearing loss did not exhibit reduced spatial release from masking when stimuli were filtered into narrow bands

local characteristic p completions of weak bn pairs this paper establishes recognition theorems for the finite lie type groups defined in odd characteristic p the hypotheses of these theorems are couched in terms of certain local data in the form of an amalgam which is called a weak bn pair of rank 2 the groups to be recognized are completions of these amalgams which satisfy the condition of being of local characteristic p a condition satisfied by the finite lie type groups defined in characteristic p the results presented will find application in one of the ongoing revisions of the finite simple group classification

speech reception by listeners with real and simulated hearing impairment effects of continuous and interrupted noise the effects of audibility and age on masking for sentences in continuous and interrupted noise were examined in listeners with real and simulated hearing loss the absolute thresholds of each of ten listeners with sensorineural hearing loss were simulated in normal hearing listeners through a combination of spectrally shaped threshold noise and multi band expansion for octave bands with center frequencies from 0 25 8 khz each individual hearing loss was simulated in two groups of three normal hearing listeners an age matched and a non age matched group the speech to noise ratio s n for 50 correct identification of hearing in noise test hint sentences was measured in backgrounds of continuous and temporally modulated 10 hz square wave noise at two overall levels for unprocessed speech and for speech that was amplified with the nal rp prescription the s n in both continuous and interrupted noise of the hearing impaired listeners was relatively well simulated in both groups of normal hearing listeners thus release from masking the difference in s n obtained in continuous versus interrupted noise appears to be determined primarily by audibility minimal age effects were observed in this small sample observed values of masking release were compared to predictions derived from intelligibility curves generated using the extended speech intelligibility index esii rhebergen et al 2006 j acoust soc am 120 3988 3997

listening to every other word examining the strength of linkage variables in forming streams of speech in a variation on a procedure originally developed by broadbent 1952 failures of attention in selective listening j exp psychol 44 428 433 listeners were presented with two sentences spoken in a sequential interleaved word format sentence one target comprised the odd numbered words in the sequence and sentence two masker comprised the even numbered words in the sequence the task was to report the words in sentence one the goal was to determine the effectiveness of cues linking the words of the target or masker over time three such linkage variables were examined 1 fixed talker 2 fixed perceived interaural location and 3 correct syntactic structure all of the linkage variables provided a significant advantage when applied to the target compared to the baseline condition in which the linkage variables were randomized however these linkage variables were not effective when applied to the masker word position effects were found such that performance in the baseline condition declined and the advantages of the linkage variables increased for the words near the end of the sentence overall this approach appears to be useful for examining interference in speech recognition that has little or no peripheral component the results suggest that variables that link target words together improve their resiliency to interference and or their recall

the performance assessment on the lifetime performance index of products following chen lifetime distribution based on the progressive type i interval censored sample abstract in the competitive manufacturing markets quality engineers frequently are dedicated to evaluate whether the quality performance of products met the desire level the lifetime performance index lpi c l is used to monitor the larger the better performance of lifetimes of products chen lifetime distribution with bathtub shape or increasing failure rate function has many applications in the lifetime data analysis the maximum likelihood estimator for c l is derived and used to propose a hypothesis testing procedure under a lower specification limit based on the progressive type i interval censored sample finally two practical examples are given to demonstrate the application of our proposed testing procedure to assess whether the lifetime performance reached the desire level

a 3 local identification of the alternating group of degree 8 the mclaughlin simple group and their automorphism groups we give 3 local identifications of the sporadic simple group mcl and its automorphism group as well as of alt 8 and sym 8

on the number of channels needed to understand speech recent studies have shown that high levels of speech understanding could be achieved when the speech spectrum was divided into four channels and then reconstructed as a sum of four noise bands or sine waves with frequencies equal to the center frequencies of the channels in these studies speech understanding was assessed using sentences produced by a single male talker the aim of experiment 1 was to assess the number of channels necessary for a high level of speech understanding when sentences were produced by multiple talkers in experiment 1 sentences produced by 135 different talkers were processed through n 2 n 16 number of channels synthesized as a sum of n sine waves with frequencies equal to the center frequencies of the filters and presented to normal hearing listeners for identification a minimum of five channels was needed to achieve a high level 90 of speech understanding asymptotic performance was achieved with eight channels at least for the speech material used in this study the outcome of experiment 1 demonstrated that the number of channels needed to reach asymptotic performance varies as a function of the recognition task and or need for listeners to attend to fine phonetic detail in experiment 2 sentences were processed through 6 and 16 channels and quantized into a small number of steps the purpose of this experiment was to investigate whether listeners use across channel differences in amplitude to code frequency information particularly when speech is processed through a small number of channels for sentences processed through six channels there was a significant reduction in speech understanding when the spectral amplitudes were quantized into a small number 8 of steps high levels 92 of speech understanding were maintained for sentences processed through 16 channels and quantized into only 2 steps the findings of experiment 2 suggest an inverse relationship between the importance of spectral amplitude resolution number of steps and spectral resolution number of channels

the assessment on the lifetime performance index of products with gompertz distribution based on the progressive type i interval censored sample abstract it is a very important topic in the manufacturing industry to evaluate whether the quality of products adhered to the desire level the larger the better process capability index pci c l is frequently used to measure the performance of lifetimes of products gompertz distribution has many applications in the lifetime data analysis the maximum likelihood estimator for c l is utilized to develop a hypothesis testing procedure with respect to a lower specification limit based on the progressive type i interval censored sample finally two practical examples are given to demonstrate the application of our proposed testing procedure to assess whether the lifetime performance reached the desire level

the importance of temporal fine structure information in speech at different spectral regions for normal hearing and hearing impaired subjects speech reception thresholds srts were measured for target and competing speech signals processed to contain variable amounts of temporal fine structure tfs information signals were filtered into 30 1 erb n wide channels where erb n refers to the bandwidth of normal auditory filters which were either tone vocoded preserving temporal envelope information extracted using the hilbert transform or left unprocessed containing both tfs and envelope information improvements in srt were compared when tfs was progressively introduced starting with the high or low frequency channels the results suggest some redundancy in the tfs information across frequency regions in a second experiment the signal was divided into five 6 erb n wide spectral regions four of which were tone vocoded the remaining region was either absent creating a spectral notch or was present and unprocessed srts were measured for normal hearing and hearing impaired subjects conditions where all channels were vocoded or unprocessed were also included normal hearing subjects benefited similarly when tfs information was added to each region suggesting that tfs information is important over a wide frequency range hearing impaired subjects benefited less although the benefit varied across subjects benefit from tfs information in speech was correlated with a psychophysical measure of tfs sensitivity obtained at two center frequencies

interval estimation of parameters of life from progressively censored data a conditional method of inference is used to derive exact confidence intervals for several life characteristics such as location scale quantiles and reliability when the data are type ii progressively censored the method is shown to be feasible and practical although a computer program may be required for its implementation the method is applied for the purpose of illustration to the extreme value and the one and two parameter exponential models prediction limits for the lifelength of future units are also discussed an example consisting of data from an accelerated test on insulating fluid reported by nelson is used for illustration and comparison

gap detection in normal and hearing impaired listeners temporal resolution estimated by measuring the minimum detectable gap t msec separating two successive signals was assessed in five normal hearing and five cochlear impaired listeners the signals were octave band noises 400 800 hz 800 1600 hz and 2000 4000 hz presented in a background of continuous broadband notched noise that was applied to eliminate unwanted spectral cues temporal resolution in all listeners showed systematic improvement with an increase in octave band center frequency resolution in the hearing impaired subjects was significantly poorer than normal regardless of whether the comparisons were made at equal sound pressure level or at equal sensation level

computational testing algorithmic procedure of assessment for lifetime performance index of products with weibull distribution under progressive type i interval censoring the assessing of the lifetime performance is a very important topic in manufacturing or service industries process capability indices had been widely used to evaluate the process performance to the continuous improvement of quality and productivity the lifetimes of products are assumed to have weibull distribution with a known shape parameter and the larger the better lifetime performance index is considered the maximum likelihood estimator is used to estimate the lifetime performance index based on the progressive type i interval censored sample the asymptotic distribution of this estimator is also investigated we use this estimator to develop the new hypothesis testing algorithmic procedure with respect to a lower specification limit finally two practical examples are given to illustrate the use of this testing algorithmic procedure to determine whether the process is capable

sentence reception in noise from one versus two sources effects of aging and hearing loss sentence reception thresholds srts and babble detection thresholds bdts were measured for signals presented from loudspeakers located at 0 deg and 90 deg azimuth in addition the s b ratios necessary to achieve srt in the presence of a 12 talker babble were determined under three conditions in which the speech and babble were presented from the same or spatially separated loudspeakers in the first experiment normal hearing subjects were tested on two occasions the results were highly reliable with standard errors of the test retest differences of less than 1db for all conditions in the second experiment srts bdts and s b ratios were measured for three normal hearing groups 39 40 54 and 55 years and for a fourth group with presbycusis 55 years presbycusics had higher srts and bdts than all other groups regardless of age and the oldest normals had higher thresholds than younger subjects presbycusics required higher s b ratios than any of the normal groups and the oldest normal group needed a higher s b ratio compared to the youngest group all groups demonstrated a significant advantage in s b ratio when the sentences and babble sources were spatially separated compared to when they were presented from the same loudspeaker there was no significant difference in the magnitude of advantage due to spatial separation of speech and noise between the normal groups regardless of age but the presbycusics had significantly smaller advantages than all normals these findings suggest that aging alone does not impair the ability to take advantage of the spatial separation of speech and noise and that the speech reception problems of aging individuals involve various components that depend upon the nature of the listening task

atlas of finite groups maximal subgroups and ordinary characters for simple groups this atlas covers groups from the families of the classification of finite simple groups recently updated incorporating corrections

the effects of age and cochlear hearing loss on temporal fine structure sensitivity frequency selectivity and speech reception in noise temporal fine structure tfs sensitivity frequency selectivity and speech reception in noise were measured for young normal hearing nhy old normal hearing nho and hearing impaired hi subjects two measures of tfs sensitivity were used the tfs lf test interaural phase difference discrimination and the tfs2 test discrimination of harmonic and frequency shifted tones these measures were not significantly correlated with frequency selectivity after partialing out the effect of audiometric threshold suggesting that insensitivity to tfs cannot be wholly explained by a broadening of auditory filters the results of the two tests of tfs sensitivity were significantly but modestly correlated suggesting that performance of the tests may be partly influenced by different factors the nho group performed significantly more poorly than the nhy group for both measures of tfs sensitivity but not frequency selectivity suggesting that tfs sensitivity declines with age in the absence of elevated audiometric thresholds or broadened auditory filters when the effect of mean audiometric threshold was partialed out speech reception thresholds in modulated noise were correlated with tfs2 scores but not measures of frequency selectivity or tfs lf test scores suggesting that a reduction in sensitivity to tfs can partly account for the speech perception difficulties experienced by hearing impaired subjects

a computational algorithm for the evaluation on the lifetime performance index of products with rayleigh distribution under progressive type i interval censoring abstract it is a very important topic these days to assessing the lifetime performance of products in manufacturing or service industries lifetime performance indices c l is used to measure the larger the better type quality characteristics to evaluate the process performance for the improvement of quality and productivity the lifetimes of products are assumed to have rayleigh distribution the maximum likelihood estimator is used to estimate the lifetime performance index based on the progressive type i interval censored sample the asymptotic distribution of this estimator is also developed we use this estimator to build the new hypothesis testing algorithmic procedure with respect to a lower specification limit finally two practical examples are given to illustrate the use of this testing algorithmic procedure to determine whether the process is capable

the influence of non spatial factors on measures of spatial release from masking this study tested the hypothesis that the reduction in spatial release from masking srm resulting from sensorineural hearing loss in competing speech mixtures is influenced by the characteristics of the interfering speech a frontal speech target was presented simultaneously with two intelligible or two time reversed unintelligible speech maskers that were either colocated with the target or were symmetrically separated from the target in the horizontal plane the difference in srm between listeners with hearing impairment and listeners with normal hearing was substantially larger for the forward maskers deficit of 5 8 db than for the reversed maskers deficit of 1 6 db this was driven by the fact that all listeners regardless of hearing abilities performed similarly and poorly in the colocated condition with intelligible maskers the same conditions were then tested in listeners with normal hearing using headphone stimuli that were degraded by noise vocoding reducing the number of available spectral channels systematically reduced the measured srm and again more so for forward reduction of 3 8 db than for reversed speech maskers reduction of 1 8 db the results suggest that non spatial factors can strongly influence both the magnitude of srm and the apparent deficit in srm for listeners with impaired hearing

solving parameter estimation problem in new product diffusion models in this paper we propose a new method for the parameter identification in new product diffusion models the method can be used regardless of whether the analytical solution of the differential equation describing the model is known or not this is the main advantage of our method over the known methods another advantage of this method is the simplicity of its implementation and negligible computing time the method is based on finite differences method and the moving least squares method for data smoothing

improved time censored reliability test plans for k out of n gamma systems abstract relevant prior knowledge supported by historical data and expert judgments is common in many manufacturing processes the classical viewpoint to the determination of acceptance sampling plans for k out of n gamma systems is generalized to those situations in which the available previous information is appreciable a beta distribution with a reduced parameter space is adopted to describe the stochastic behavior of the fraction of defective systems an integer nonlinear programming problem is stated to find the inspection scheme that minimizes the required number of components to test and keeps the average producer and consumer risks below specified thresholds first lower and upper bounds as well as an approximate solution are derived then an efficient step by step procedure which finds the best acceptance sampling plan in a finite number of iterations is provided the inclusion of prior information into the decision process provides substantial savings in the sample size required for demonstrating system reliability and also more accurate assessments of the actual producer and consumer risks a system of five water pumps for cooling a reactor is analyzed for illustrative and comparative purposes

the effect of age on auditory spatial attention in conditions of real and simulated spatial separation the contributions of auditory and cognitive factors to age dependent differences in auditory spatial attention were investigated in conditions of real spatial separation the target sentence was presented from a central location and competing sentences were presented from left and right locations in conditions of simulated spatial separation different apparent spatial locations of the target and competitors were induced using the precedence effect the identity of the target was cued by a callsign presented either prior to or following each target sentence and the probability that the target would be presented at the three locations was specified at the beginning of each block younger and older adults with normal hearing sensitivity below 4khz completed all 16 conditions 2 spatial separation method 2 callsign conditions 4 probability conditions overall younger adults performed better than older adults for both age groups performance improved with target location certainty with a priori tar

gap detection and the precedence effect in young and old adults thresholds for detecting a gap between two gaussian enveloped standard deviation 0 5 ms 2 khz tones were determined in young and old listeners the gap detection thresholds of old adults were more variable and about twice as large as those obtained from young adults moreover gap detection thresholds were not correlated with audiometric thresholds in either group estimates of the width of the temporal window of young subjects based on the detection of a gap between two tone pips were smaller than those typically obtained when a relatively long duration pure tone is interrupted moore et al j acoust soc am 85 1266 1275 1989 because the amount of time it takes to recover from an adapting stimulus is likely to affect gap detection thresholds glasberg et al j acoust soc am 81 1546 1556 1987 smaller estimates of temporal window size would be expected in this paradigm if the amount of adaptation produced by the first tone pip was negligible the larger gap detection thresholds of o

estimation of parameters of the shifted gompertz distribution using least squares maximum likelihood and moments methods nonlinear least squares procedures for estimating the parameters of the shifted gompertz distribution are proposed simulation studies are carried out to compare weighted and unweighted least squares methods the maximum likelihood method and method of moments this work concludes that least squares methods via weighting factors to estimate the parameters of this probability distribution give a better performance than unweighted least squares methods showing the importance of weighting factors besides results of this simulation study show that a good performance is obtained using the maximum likelihood method and the estimators obtained with more bias are those of the method of moments

application of the newton iteration algorithm to the parameter estimation for dynamical systems this paper uses the newton iteration to study new identification methods for determining the parameters of dynamical systems from step responses on the basis of the step response analysis we present the newton iterative algorithms moreover in order to test the accuracy of the estimated parameters the frequency and step response experiment are applied to the dynamical systems between the estimated and true models the simulation results show that the obtained models can capture the dynamics of the systems i e the estimated model s outputs are close to the outputs of the actual systems this confirms the effectiveness of the proposed newton iterative identification methods

informational processing of complex sound i intensity discrimination this paper reports on some initial experiments using the sample discrimination paradigm to investigate normal hearing listeners ability to process information in complex nonspeech sounds an important feature of the sample discrimination experiment is that the value of the d i f f e r e n c e to be discriminated randomly varies from trial to trial it is this variation that yields potential information in the present study listeners heard a pair of multitone complexes or sequences on each trial the individual levels of the tones were drawn from two normal distributions differing only in mean the listener s task was to identify the sound having the higher mean tone level for an ideal observer in these experiments performance in d grows as the square root n where n is the number of tones obtained d grew more nearly as the cube root of n regardless of whether the tones were played sequentially or simultaneously or whether they were increased in number from high frequencies to low or from low frequencies to high a preliminary model is proposed in which discrimination performance depends predominantly on the information content of the sounds and is largely independent of the physical dimensions along which the sounds vary information content is defined in terms of the variance of the underlying stimulus distributions and a stimulus equivocation factor that is derived from the data based on this model transmitted information is estimated to be between 1 0 and 2 6 bits

release from speech on speech masking by adding a delayed masker at a different location the amount of masking exerted by one speech sound on another can be reduced by presenting the masker twice from two different locations in the horizontal plane with one of the presentations delayed to simulate an acoustical reflection three experiments were conducted on various aspects of this phenomenon experiment 1 varied the number of masking talkers from one to three and the signal to noise s n ratio from 12to 4db evidence of masking release was found for every combination of these variables tested for the most difficult conditions multiple maskers and negative s n the amount of release was approximately 10db experiment 2 varied the timing of leading and lagging masker presentations over a broad range to include shorter delay times where room reflections of speech are rarely noticed by listeners and longer delays where reflections can become disruptive substantial masking release was found for all of the shorter delay times tested and negligible release was found at the longer delays f

temporal resolution in sensorineural hearing impaired listeners temporal masking curves were obtained from 12 normal hearing and 16 hearing impaired listeners using 200 ms 1000 hz pure tone maskers and 20 ms 1000 hz fixed level probe tones for the delay times used here 40 ms temporal masking curves obtained from both groups can be well described by an exponential function with a single level independent time constant for each listener normal hearing listeners demonstrated time constants that ranged between 37 and 67 ms with a mean of 50 ms most hearing impaired listeners with significant hearing loss at the probe frequency demonstrated longer time constants range 58 114 ms than those obtained from normal hearing listeners time constants were found to grow exponentially with hearing loss according to the function 52e0 011 hl when the slope of the growth of masking is unity the longest individual time constant was larger than normal by a factor of 2 3 for a hearing loss of 52 db the steep slopes of the growth of masking functions typically observed

effect of enhancement of spectral changes on speech intelligibility and clarity preferences for the hearing impaired most information in speech is carried in spectral changes over time rather than in static spectral shape per se a form of signal processing aimed at enhancing spectral changes over time was developed and evaluated using hearing impaired listeners the signal processing was based on the overlap add method and the degree and type of enhancement could be manipulated via four parameters two experiments were conducted to assess speech intelligibility and clarity preferences three sets of parameter values one corresponding to a control condition two types of masker steady speech spectrum noise and two talker speech and two signal to masker ratios smrs were used for each masker type generally the effects of the processing were small although intelligibility was improved by about 8 percentage points relative to the control condition for one set of parameter values using the steady noise masker at 6 db smr the processed signals were not preferred over those for the control condition except for the steady noise masker at 6 db smr further work is needed to determine whether tailoring the processing to the characteristics of the individual hearing impaired listener is beneficial

the skew reflected gompertz distribution for analyzing symmetric and asymmetric data abstract in this work we have defined a new family of skew distribution the skew reflected gompertz we have also derived some of its probabilistic and inferential properties the maximum likelihood estimates of the proposed distribution parameters are obtained via an em algorithm and performances of the proposed model and its estimates are shown via simulation studies as well as real applications three real datasets are also used to illustrate the model performance which can compete against some well known skew distributions frequently used in applications

nonlinear weighted least squares estimation of a three parameter weibull density with a nonparametric start this paper is concerned with the parameter estimation problem for the three parameter weibull density which is widely employed as a model in reliability and lifetime studies our approach is a combination of nonparametric and parametric methods the basic idea is to start with an initial nonparametric density estimate which needs to be as good as possible and then apply the nonlinear least squares method to estimate the unknown parameters as a main result a theorem on the existence of the least squares estimate is obtained some simulations are given to show that our approach is satisfactory if the initial density is of good enough quality

a 3 local characterization of fi24 abstract we identify fischer s group fi 24 by the structure of the centralizer of a 3 central element also as a corollary we will identify this group from two of its 3 locals

estimation of parameters of the gompertz distribution using the least squares method the gompertz distribution has been used to describe human mortality and establish actuarial tables recently this distribution has been again studied by some authors the maximum likelihood estimates for the parameters of the gompertz distribution has been discussed by garg et al j r statist soc c 19 1970 152 the purpose of this paper is to propose unweighted and weighted least squares estimates for parameters of the gompertz distribution under the complete data and the first failure censored data series systems see j statist comput simulat 52 1995 337 a simulation study is carried out to compare the proposed estimators and the maximum likelihood estimators results of the simulation studies show that the performance of the weighted least squares estimators is acceptable

moderate cochlear hearing loss leads to a reduced ability to use temporal fine structure information the ability of normally hearing and hearing impaired subjects to use temporal fine structure information in complex tones was measured subjects were required to discriminate a harmonic complex tone from a tone in which all components were shifted upwards by the same amount in hz in a three alternative forced choice task the tones either contained five equal amplitude components non shaped stimuli or contained many components but were passed through a fixed bandpass filter to reduce excitation pattern changes shaped stimuli components were centered at nominal harmonic numbers n 7 11 and 18 for the shaped stimuli hearing impaired subjects performed much more poorly than normally hearing subjects with most of the former scoring no better than chance when n 11 or 18 suggesting that they could not access the temporal fine structure information performance for the hearing impaired subjects was significantly improved for the non shaped stimuli presumably because they could benefit from spectral cues it is proposed that normal hearing subjects can use temporal fine structure information provided the spacing between fine structure peaks is not too small relative to the envelope period but subjects with moderate cochlear hearing loss make little use of temporal fine structure information for unresolved components