bluuebunny/crossref_metadata_2025 huggingface dataset:
An International Investigation of Problem‐Solving Performance in the Semiconductor Industry*
Authors: Appleyard Melissa M. , Brown Clair , Sattler Linda
Published: March 2006

Using a unique survey of engineers in major semiconductor companies located in Japan, South Korea, and the United States, this article analyzes how a firm's human resource (HR) system (i.e., practices that structure work, develop skills, and reward performance) and knowledge system (i.e., information access, sharing and control) are related to the problem‐solving performance of engineers. Because of the short product market life cycles in the semiconductor industry, expeditious problem solving is an important performance goal. Therefore, this article examines the performance of engineers in terms of the time it takes them to solve problems in the context of their firms' HR and knowledge systems. It was anticipated during this study that externally oriented organizational systems, which support individual career performance and mobility (an externally oriented HR system) and the use of private knowledge sources (an externally oriented knowledge system), would be associated with superior performance in terms of problem‐solving speed. The findings support this hypothesis and demonstrate the importance of externally oriented HR systems and at the same time suggest the surprising insignificance of the orientation of the knowledge systems. These findings are applicable to engineers in the sample from the United States, whereas the findings for the Korean and Japanese engineers are inconclusive. International variation is found where the U.S. engineers work under the most externally oriented and the Japanese engineers under the least externally oriented systems, and the Korean engineers fall in between. The findings of this article suggest that when constructing a work environment for new product development, managers should take into account how the underlying components of their organizational systems contribute to an internal or external focus, and how this orientation may influence performance.
Toward a Parsimonious Definition of Traditional and Electronic Mass Customization
Authors: Kaplan Andreas M. , Haenlein Michael
Published: March 2006

Although mass customization, a term introduced by Davis (1987) to describe the oxymoron of mass producing customized products, has been part of research for more than a decade, literature has not come up with a commonly accepted definition of this term up to now. The present article attempts to close this gap by proposing a definition of traditional and electronic mass customization, which is based on answering three research questions. First, for which kind of customized goods (products versus services) is mass customization applicable at all? Second, at which step of the value creation process must the customer be given the chance to customize his or her good to be able to speak of mass customization? And finally, which prerequisites in terms of production cost and monetary price need to be fulfilled when comparing mass‐customized with mass‐produced goods? Using an extensive analysis of extant literature in the field, the authors develop two definitions of traditional mass customization, a working and a visionary one, as well as one for electronic mass customization, stating how new opportunities arising from advances in communication and information technology can influence this concept.
Two‐Dimensional Transthoracic Contrast Echocardiographic Assessment of Metastatic Left Ventricular Tumors
Authors: Yelamanchili Pridhvi , Wanat Francis E. , Knezevic Dusan , Nanda Navin C. , Patel Vinod
Published: March 2006

To illustrate the usefulness of contrast echocardiography in the assessment of cardiac tumors, we present an 81‐year‐old female with pathological fracture of the right clavicle in whom biopsy showed poorly differentiated carcinoma. Two‐dimensional transthoracic echocardiography found two masses in the left ventricle attached to mid‐ventricular septum consistent with metastases. Echo contrast study with octafluoropropane (Optison) showed contrast enhancement of both the masses consistent with high vascularity seen in a malignant tumor.
Echocardiographic Study of Cardiac Morphological and Functional Changes before and after Parturition in Pregnancy‐Induced Hypertension
Authors: Yuan Lijun , Duan Yunyou , Cao Tiesheng
Published: March 2006

Purpose: To investigate the cardiac morphological and functional changes by echocardiography, before and after parturition in patients with pregnancy‐induced hypertension (PIH). Methods: The parameters related to cardiac morphology and left ventricular diastolic and systolic functions were compared before and after parturition in 32 patients with PIH and 24 normal pregnant (NP) women. Results: Compared with NP women, the PIH patients had greater diameters of left atrium and left ventricle in end‐diastole (LAd: 38.9 ± 4.5 vs 34.6 ± 4.4 mm, P = 0.0015; LVEDd: 51.2 ± 5.8 vs 47.1 ± 4.2 mm, P = 0.036) and lower E/A (1.2 ± 0.2 vs 1.4 ± 0.2, P = 0.009) and greater fractional shortening (FS) (39.8 ± 6.5% vs 37.1 ± 6.9%, P = 0.042) and ejection fraction (EF) (0.72 ± 0.07 vs 0.66 ± 0.08, P = 0.040). Pericardial effusion (PE) occurred in 31.3% and 16.7% of PIH and NP, respectively. The LAd and LVEDd in 70% and 47% patients with PIH resolved and PE disappeared in 80% of PIH patients postpartum. E/A ratio in PIH significantly increased after parturition, while the two patients with cardiac systolic dysfunction did not improve very much. Conclusions: Compared with normal pregnancy, the most significant cardiac morphological changes in PIH are the greater diameters of left atrium and left ventricle, thicker inter‐ventricular septum (IVS), more PE, impaired left ventricular diastolic function, and increased systolic function. The PE could disappear in PIH and about half of other abnormalities could recover to be the level of normal pregnancy postpartum within 2 months.
Genetic analysis of HLA, NA and HPA typing in type 2 diabetes and ASO
Authors: Nomura S. , Shouzu A. , Omoto S. , Matsuzaki T. , Yamaoka M. , Abe M. , Hosokawa M. , Nishikawa M. , Iwasaka T. , Fukuhara S.
Published: March 2006

We examined the genetic status of human leucocyte antigens (HLA), human platelet alloantigens (HPA) and neutrophil‐specific antigens (NA) in patients with type 2 diabetes mellitus and diabetic arteriosclerosis obliterans (ASO). To our knowledge, the present study is the first report showing the relationship among three genetic factors in type 2 diabetes mellitus and ASO patients. HLA typing was performed by the polymerase chain reaction (PCR)–restriction fragment length polymorphism method. HPA‐typing and NA‐typing were by a PCR‐sequence‐specific primer method. The incidence of HLA‐DRB1*1501 was found to be significant in type 2 diabetes and non‐diabetic, particularly ASO‐positive patients, compared to control subjects. There were no differences in NA1/NA2 between the control and diabetic or non‐diabetic ASO groups. However, the frequency of NA2/NA2 in ASO‐positive diabetes and non‐diabetic ASO patients was significantly higher than controls. The a/b genotype of HPA‐5a/5b was significantly lower in type 2 diabetes and non‐diabetic ASO‐positive patients than in controls. These findings suggest that genetic studies of HLA, NA and HPA could be useful to understand the pathogenesis of type 2 diabetes and ASO.
Intramural tracheal haematoma causing acute respiratory obstruction in a dog
Authors: Pink J. J.
Published: March 2006

Respiratory obstruction resulting from a discrete haematoma within the dorsal tracheal membrane was seen in an 11‐year‐old neutered female greyhound that had been involved in a fight two days earlier. There was no history or evidence of rodenticide toxicity or other coagulopathy, and it is suggested that the tracheal haematoma resulted from trauma. A right third intercostal thoracotomy was performed and this allowed resection of the haematoma from within the dorsal membrane of the cranial thoracic trachea, relieving the obstruction with no subsequent signs of dyspnoea. Intramural haematoma should be considered as a rare differential diagnosis for dogs presenting with acute respiratory obstruction.
Tracheal foreign bodies in the cat and the use of fluoroscopy for removal: 12 cases
Authors: Tivers M. S. , Moore A. Hotston
Published: March 2006

Objectives:To gather information to support the use of fluoroscopically guided removal of tracheal foreign bodies in cats. It was also the intent to produce a case series and look at the long‐term outcome following tracheal foreign body removal.

Methods:A retrospective study was performed. This looked at cases of tracheal foreign bodies in cats seen at the University of Bristol veterinary school at Langford over an eight‐year period. Outcome was assessed via telephone conversations with the owners.

Results:Twelve cats were presented with tracheal foreign bodies during this time. Ten of these foreign bodies were successfully removed using fluoroscopy and two using bronchoscopy. All cats survived. Follow‐up was available for nine cats and showed no long‐term complications.

ClinicalSignificance:Forceps removal under fluoroscopic guidance is a rapid, safe, and effective method for removal of tracheal foreign bodies in cats. It should be considered as an alternative to bronchoscopy for removal of tracheal foreign bodies in cats. Indeed, in cases where bronchoscopy has failed, it can be attempted to avoid thoracotomy. Successful removal of tracheal foreign bodies in cats is associated with a good long‐term outcome.
Laryngeal collapse in seven brachycephalic puppies
Authors: Pink J. J. , Doyle R. S. , Hughes J. M. L. , Tobin E. , Bellenger C. R.
Published: March 2006

Objectives:To document the histories, clinical findings, and management of seven puppies with laryngeal collapse occurring secondarily to brachycephalic airway syndrome.

Methods:Seven brachycephalic puppies aged between 4·5 and six months underwent surgery for management of brachycephalic airway syndrome following presentation for exercise intolerance and increased respiratory noise and effort.

Results:Stenotic nares of varying severity and an elongated soft palate were common to all dogs. All dogs had tracheal hypoplasia and this was severe in four dogs. Laryngeal collapse was present in all dogs. Two dogs had stage I, four dogs stage II, and one dog stage III laryngeal collapse. The dog with stage III laryngeal collapse and one dog with stage II laryngeal collapse died. There was no apparent association between the changes evident on thoracic radiographs or the degree of tracheal hypoplasia and postoperative outcome.

ClinicalSignificance:The development of severe secondary laryngeal changes in dogs aged six months or less supports the suggestion that immature brachycephalic dogs should undergo assessment and, if indicated, surgery as soon as any clinical signs of BAS are apparent.
Perception of the [m]-[n] distinction in consonant-vowel (CV) and vowel-consonant (VC) syllables produced by child and adult talkers
Authors: Ohde Ralph N. , Haley Katarina L. , Barnes Christine W.
Published: March 2006

The contribution of the nasal murmur and vocalic formant transition to the perception of the [m]-[n] distinction by adult listeners was investigated for speakers of different ages in both consonant-vowel (CV) and vowel-consonant (VC) syllables. Three children in each of the speaker groups 3, 5, and 7years old, and three adult females and three adult males produced CV and VC syllables consisting of either [m] or [n] and followed or preceded by [i æ u a], respectively. Two productions of each syllable were edited into seven murmur and transitions segments. Across speaker groups, a segment including the last 25ms of the murmur and the first 25ms of the vowel yielded higher perceptual identification of place of articulation than any other segment edited from the CV syllable. In contrast, the corresponding vowel+murmur segment in the VC syllable position improved nasal identification relative to other segment types for only the adult talkers. Overall, the CV syllable was perceptually more distinctive than the VC syllable, but this distinctiveness interacted with speaker group and stimulus duration. As predicted by previous studies and the current results of perceptual testing, acoustic analyses of adult syllable productions showed systematic differences between labial and alveolar places of articulation, but these differences were only marginally observed in the youngest children’s speech. Also predicted by the current perceptual results, these acoustic properties differentiating place of articulation of nasal consonants were reliably different for CV syllables compared to VC syllables. A series of comparisons of perceptual data across speaker groups, segment types, and syllable shape provided strong support, in adult speakers, for the “discontinuity hypothesis” [K. N. Stevens, in Phonetic Linguistics: Essays in Honor of Peter Ladefoged, edited by V. A. Fromkin (Academic, London, 1985), pp. 243–255], according to which spectral discontinuities at acoustic boundaries provide critical cues to the perception of place of articulation. In child speakers, the perceptual support for the “discontinuity hypothesis” was weaker and the results indicative of developmental changes in speech production.
Extrinsic context affects perceptual normalization of lexical tone
Authors: Francis Alexander L. , Ciocca Valter , Wong Natalie King Yu , Leung Wilson Ho Yin , Chu Phoebe Cheuk Yan
Published: March 2006

The present study explores the use of extrinsic context in perceptual normalization for the purpose of identifying lexical tones in Cantonese. In each of four experiments, listeners were presented with a target word embedded in a semantically neutral sentential context. The target word was produced with a mid level tone and it was never modified throughout the study, but on any given trial the fundamental frequency of part or all of the context sentence was raised or lowered to varying degrees. The effect of perceptual normalization of tone was quantified as the proportion of non-mid level responses given in F0-shifted contexts. Results showed that listeners’ tonal judgments (i) were proportional to the degree of frequency shift, (ii) were not affected by non-pitch-related differences in talker, (iii) and were affected by the frequency of both the preceding and following context, although (iv) following context affected tonal decisions more strongly than did preceding context. These findings suggest that perceptual normalization of lexical tone may involve a “moving window” or “running average” type of mechanism, that selectively weights more recent pitch information over older information, but does not depend on the perception of a single voice.
Acoustic features of objects matched by an echolocating bottlenose dolphin
Authors: DeLong Caroline M. , Au Whitlow W. L. , Lemonds David W. , Harley Heidi E. , Roitblat Herbert L.
Published: March 2006

The focus of this study was to investigate how dolphins use acoustic features in returning echolocation signals to discriminate among objects. An echolocating dolphin performed a match-to-sample task with objects that varied in size, shape, material, and texture. After the task was completed, the features of the object echoes were measured (e.g., target strength, peak frequency). The dolphin’s error patterns were examined in conjunction with the between-object variation in acoustic features to identify the acoustic features that the dolphin used to discriminate among the objects. The present study explored two hypotheses regarding the way dolphins use acoustic information in echoes: (1) use of a single feature, or (2) use of a linear combination of multiple features. The results suggested that dolphins do not use a single feature across all object sets or a linear combination of six echo features. Five features appeared to be important to the dolphin on four or more sets: the echo spectrum shape, the pattern of changes in target strength and number of highlights as a function of object orientation, and peak and center frequency. These data suggest that dolphins use multiple features and integrate information across echoes from a range of object orientations.
Functional data analysis of prosodic effects on articulatory timing
Authors: Lee Sungbok , Byrd Dani , Krivokapić Jelena
Published: March 2006

An application of functional data analysis (FDA) (Ramsay and Silverman, 2005, Functional Data Analysis, 2nd ed. (Springer-Verlag, New York)) for linguistic experimentation is explored. The functional time-registration method provided by FDA is shown to offer novel advantages in the investigation of articulatory timing. Traditionally, articulatory studies examining the effects of linguistic variables such as prosody on articulatory timing have relied on comparing the durations of speech intervals of interest defined by kinematic landmarks. Such measurements, however, do not preserve information on the detailed, continuous pattern of articulatory timing that unfolds during these intervals. We present an approach that allows the analysis of entire, continuous kinematic trajectories obtained in a movement tracking experiment examining the influence of a phrasal boundary on articulatory patterning. FDA time deformation functions, after alignment of test and reference (control) signals, reveal delaying of articulator movement (i.e., slowing of the internal clock rate) in the presence of a phrase boundary as the speech stream recedes from the boundary. This is a theoretically predicted pattern (Byrd and Saltzman, 2003, The elastic phrase: Modeling the dynamics of boundary-adjacent lengthening, Journal of Phonetics 31, 149–180.), which would be more difficult to validate with a traditional interval-based approach. It is concluded that the FDA time alignment method provides a useful tool for characterizing timing patterns in linguistic experimentation based on continuous kinematic trajectories.
Effects of nonlinear propagation, cavitation, and boiling in lesion formation by high intensity focused ultrasound in a gel phantom
Authors: Khokhlova Vera A. , Bailey Michael R. , Reed Justin A. , Cunitz Bryan W. , Kaczkowski Peter J. , Crum Lawrence A.
Published: March 2006

The importance of nonlinear acoustic wave propagation and ultrasound-induced cavitation in the acceleration of thermal lesion production by high intensity focused ultrasound was investigated experimentally and theoretically in a transparent protein-containing gel. A numerical model that accounted for nonlinear acoustic propagation was used to simulate experimental conditions. Various exposure regimes with equal total ultrasound energy but variable peak acoustic pressure were studied for single lesions and lesion stripes obtained by moving the transducer. Static overpressure was applied to suppress cavitation. Strong enhancement of lesion production was observed for high amplitude waves and was supported by modeling. Through overpressure experiments it was shown that both nonlinear propagation and cavitation mechanisms participate in accelerating lesion inception and growth. Using B-mode ultrasound, cavitation was observed at normal ambient pressure as weakly enhanced echogenicity in the focal region, but was not detected with overpressure. Formation of tadpole-shaped lesions, shifted toward the transducer, was always observed to be due to boiling. Boiling bubbles were visible in the gel and were evident as strongly echogenic regions in B-mode images. These experiments indicate that nonlinear propagation and cavitation accelerate heating, but no lesion displacement or distortion was observed in the absence of boiling.
Fundamental frequency of infants’ and parents’ utterances in longitudinal recordings
Authors: Amano Shigeaki , Nakatani Tomohiro , Kondo Tadahisa
Published: March 2006

The fundamental frequencies (F0) of daily life utterances of Japanese infants and their parents from the infant’s birth until about 5years of age were longitudinally analyzed. The analysis revealed that an infant’s F0 mean decreases as a function of month of age. It also showed that within- and between-utterance variability in infant F0 is different before and after the onset of two-word utterances, probably reflecting the difference between linguistic and nonlinguistic utterances. Parents’ F0 mean is high in infant-directed speech (IDS) before the onset of two-word utterances, but it gradually decreases and reaches almost the same value as in adult-directed speech after the onset of two-word utterances. The between-utterance variability of parents’ F0 in IDS is large before the onset of two-word utterances and it subsequently becomes smaller. It is suggested that these changes of parents’ F0 are closely related to the feasibility of communication between infants and parents.
The Stokes relations linking time reversal and the inverse filter
Authors: Vignon F. , Aubry J.-F. , Saez A. , Tanter M. , Cassereau D. , Montaldo G. , Fink M.
Published: March 2006

Our aim in this paper is to show how two adaptive focusing techniques, Time Reversal (TR) and the Spatio Temporal Inverse Filter (STIF), are related by the Stokes equations linking waves transmitted and reflected through a medium. For that purpose a model experiment has been investigated: a solid plate located between two arrays of transducers. When sending a wave from an array to the other through the plate, multiple transmitted waves are induced. TR and STIF are used to cancel these echoes. The echoes can be suppressed by TR, using the two arrays cavity surrounding the plate. They can also be cancelled by STIF, inverting the transmission operator between the arrays. The STIF achieves echoes cancellation by using only the transmitted fields through the plate, whereas TR also requires the reflected fields. The STIF's strategy is analyzed in light of the Stokes relations: thanks to the reflections in the medium, it is able to simulate a TR cavity with only one array. A mathematical analysis of the matrix expression of the Stokes relations then leads to two iterative ways to invert the transmission operator. Finally, this general technique is applied to a more complex medium: a human skull bone..
Effect of masker-fringe onset asynchrony on overshoot
Authors: Miśkiewicz Andrzej , Buus Søren , Florentine Mary
Published: March 2006

The study examines how overshoot is influenced by masker-signal onset asynchrony when the masker contains frequencies above or below the signal frequency. Masked thresholds were measured for a 2-ms tone at 5kHz. The measurements were made in a reference condition with a narrow center-band (CB) noise masker (4590–5464Hz), and in conditions with either a low-fringe (1900–4590Hz) or a high-fringe noise band (5500–11000Hz) added to the CB. The signal always came on 2ms after the onset of the CB. The time interval between fringe and signal onsets varied from −98ms (signal onset before fringe onset) to +502ms (signal onset after fringe onset). Results show that overshoot is largest, 8–11dB, for a high fringe with onset occurring between 8ms before the signal onset and 12ms after it. Thus, pronounced overshoot is observed even when the high fringe is gated on after the signal’s offset. Low fringes produce no more than 4dB of overshoot, much less than high fringes produce. The finding of pronounced overshoot elicited by a high fringe presented shortly after the end of the signal suggests that overshoot is governed, at least in part, by central mechanisms.
Centralized and decentralized control of structural vibration and sound radiation
Authors: Engels Wouter P. , Baumann Oliver N. , Elliott Stephen J. , Fraanje R.
Published: March 2006

This paper examines the performance of centralized and decentralized feedback controllers on a plate with multiple colocated velocity sensors and force actuators. The performance is measured by the reduction in either kinetic energy or sound radiation, when the plate is excited with a randomly distributed, white pressure field or colored noise. The trade-off between performance and control effort is examined for each case. The controllers examined are decentralized absolute velocity feedback, centralized absolute velocity feedback control and linear quadratic Gaussian (LQG) control. It is seen that, despite the fact that LQG control is a centralized, dynamic controller, there is little overall performance improvement in comparison to decentralized direct velocity feedback control if both are limited to the same control effort.
The relation between electrophysiologic channel interaction and electrode pitch ranking in cochlear implant recipients
Authors: Hughes Michelle L. , Abbas Paul J.
Published: March 2006

The primary goal of this study was to examine the relation between electrophysiologic measures of channel interaction and the ability to discriminate pitch between electrodes in a psychophysical pitch-ranking task. It was hypothesized that cochlear implant recipients should perform better on an electrode pitch-ranking task when using electrodes with less channel interaction as measured with the electrically evoked compound action potential (ECAP). The width of the ECAP channel interaction function was compared with the slope of the pitch-ranking function for 10 adult Nucleus 24 recipients. Results showed no significant correlation between electrode pitch-ranking ability and width of the ECAP channel interaction function for individual subjects or for group data. Additionally, there was no significant correlation between speech perception performance and either pitch-ranking ability or width of the ECAP channel interaction function. These results suggest that the width of the ECAP interaction function may not be an accurate predictor of the ability to discriminate between electrodes on the basis of pitch.
Electrophysiologic channel interaction, electrode pitch ranking, and behavioral threshold in straight versus perimodiolar cochlear implant electrode arrays
Authors: Hughes Michelle L. , Abbas Paul J.
Published: March 2006

The primary goal of this study was to examine electrophysiologic measures of channel interaction, electrode pitch discrimination ability using a pitch-ranking task, and behavioral threshold levels in individuals implanted with a straight electrode array versus a perimodiolar array. It was hypothesized that perimodiolar arrays should yield lower thresholds, less channel interaction as measured with the electrically evoked compound action potential (ECAP), and better electrode pitch-ranking ability. Results from ten adult Nucleus 24 recipients (N=5 straight array, N=5 perimodiolar Contour array) showed no significant difference in threshold between the two electrode designs; however, there was significantly better electrode pitch-ranking ability and less channel interaction as measured with the ECAP for perimodiolar electrodes. Additionally, there was a significant positive correlation between behavioral threshold and width of the ECAP interaction function for Contour group data. There was no significant correlation between behavioral threshold and electrode pitch-ranking ability. These data suggest that electrode design and∕or perimodiolar position may reduce physiologic channel interaction in the cochlea and improve electrode pitch discrimination ability; however, this positive finding did not translate into significantly better speech perception ability for Contour subjects.
Estimates of effective frequency selectivity based on the detection of a tone added to complex maskers
Authors: Richards Virginia M. , Tang Zhongzhou
Published: March 2006

In Experiment 1, the validity of parameters associated with the roex(p,r) auditory filter shape was examined for three different types of maskers: (a) A noise masker, (b) a random 12-tone masker whose frequencies varied on a burst-by-burst basis [multiple-burst different (MBD)], and (c) a random 12-tone masker whose frequencies were the same across bursts [multiple-burst same (MBS)]. First, the power spectrum model of masking was used to estimate auditory filter shapes for four observers. Second, the resulting auditory filter shapes were used in a computer simulation that provided an estimate of internal noise for each observer. Third, relative weights across frequency were estimated for each observer and each masker type. For the noise masker, these analyses provided predictions and relative weights that were consistent across the three analyses. For the MBD and MBS maskers, there was little consistency; neither the estimated internal noise nor the estimated relative weights reliably supported a single-filter model of detection. In Experiment 2, the time course for the detection of a tone added to an MBD masker was evaluated by estimating relative weights jointly in time and frequency. The relative weights at the signal frequency formed a rough inverse “U” across time.
Classification of shallow-water acoustic signals via alpha-Stable modeling of the one-dimensional wavelet coefficients
Authors: Taroudakis Michael I. , Tzagkarakis George , Tsakalides Panagiotis
Published: March 2006

A novel statistical scheme is presented for the classification of shallow water acoustic signals according to the environmental parameters of the medium through which they have propagated. An efficient way to classify these signals is important for inverse procedures in underwater acoustics aiming at the recovery of the geoacoustic parameters of an oceanic environment, using measurements of the acoustic field due to an acoustic source. An important issue in this procedure is the determination of an efficient “observable” of the acoustic signal (feature extraction), which characterizes the signal in connection with the recoverable parameters. The proposed method is based on a transformation of the acoustic signals via a one-dimensional (1D) wavelet decomposition and then by fitting the distribution of the subband coefficients using an appropriate function. We observe that statistical distributions with heavy algebraic tails, such as the alpha-Stable family, are often very accurate in capturing the non-Gaussian behavior of the subband coefficients. As a result, the feature extraction step consists of estimating the parameters of the alpha-Stable model, while the similarity between two distinct signals is measured by employing the Kullback–Leibler Divergence between their corresponding alpha-Stable distributions. The performance of the proposed classification method is studied using simulated acoustic signals generated in a shallow water environment.
An experimental demonstration of blind ocean acoustic tomography
Authors: Jesus Sérgio M. , Soares Cristiano , Coelho Emanuel , Picco Paola
Published: March 2006

Despite the advantages clearly demonstrated by ocean acoustic tomography (OAT) when compared to other ocean monitoring techniques, it suffers from several technical-related drawbacks. One is the requirement for rather expensive equipment to be maintained and operated at several locations in order to obtain sufficient source–receiver propagation paths to cover a given ocean volume. This paper presents the preliminary feasibility tests of a concept that uses ships of opportunity as sound sources for OAT. The approach adopted in this paper views the tomographic problem as a global inversion that includes determining both the emitted signal and the environmental parameters, which is a similar problem to that seen in blind channel identification and was therefore termed blind ocean acoustic tomography (BOAT). BOAT was tested on a data set acquired in October 2000 in a shallow-water area off the west coast of Portugal, including both active and passive (ship noise) data. Successful results show that BOAT is able to estimate detailed water column temperature profiles coherent with independent measurements in intervals where the uncontrolled source signal (ship noise) presents a sufficient bandwidth and signal-to-noise ratio, which clearly define the limitations of the presented method.
Constrained tone transformation technique for separation and combination of Mandarin tone and intonation
Authors: Ni Jinfu , Kawai Hisashi , Hirose Keikichi
Published: March 2006

This paper addresses a classical but important problem: The coupling of lexical tones and sentence intonation in tonal languages, such as Chinese, focusing particularly on voice fundamental frequency (F0) contours of speech. It is important because it forms the basis of speech synthesis technology and prosody analysis. We provide a solution to the problem with a constrained tone transformation technique based on structural modeling of the F0 contours. This consists of transforming target values in pairs from norms to variants. These targets are intended to sparsely specify the prosodic contributions to the F0 contours, while the alignment of target pairs between norms and variants is based on underlying lexical tone structures. When the norms take the citation forms of lexical tones, the technique makes it possible to separate sentence intonation from observed F0 contours. When the norms take normative F0 contours, it is possible to measure intonation variations from the norms to the variants, both having identical lexical tone structures. This paper explains the underlying scientific and linguistic principles and presents an algorithm that was implemented on computers. The method’s capability of separating and combining tone and intonation is evaluated through analysis and re-synthesis of several hundred observed F0 contours.
The use of visual cues in the perception of non-native consonant contrasts
Authors: Hazan Valerie , Sennema Anke , Faulkner Andrew , Ortega-Llebaria Marta , Iba Midori , Chung Hyunsong
Published: March 2006

This study assessed the extent to which second-language learners are sensitive to phonetic information contained in visual cues when identifying a non-native phonemic contrast. In experiment 1, Spanish and Japanese learners of English were tested on their perception of a labial∕labiodental consonant contrast in audio (A), visual (V), and audio-visual (AV) modalities. Spanish students showed better performance overall, and much greater sensitivity to visual cues than Japanese students. Both learner groups achieved higher scores in the AV than in the A test condition, thus showing evidence of audio-visual benefit. Experiment 2 examined the perception of the less visually-salient ∕l∕-∕r∕ contrast in Japanese and Korean learners of English. Korean learners obtained much higher scores in auditory and audio-visual conditions than in the visual condition, while Japanese learners generally performed poorly in both modalities. Neither group showed evidence of audio-visual benefit. These results show the impact of the language background of the learner and visual salience of the contrast on the use of visual cues for a non-native contrast. Significant correlations between scores in the auditory and visual conditions suggest that increasing auditory proficiency in identifying a non-native contrast is linked with an increasing proficiency in using visual cues to the contrast.
Cost-effective assembly of a basic fiber-optic hydrophone for measurement of high-amplitude therapeutic ultrasound fields
Authors: Parsons Jessica E. , Cain Charles A. , Fowlkes J. Brian
Published: March 2006

Design considerations, assembly details, and operating procedures of one version of a cost-effective basic fiber-optic probe hydrophone (FOPH) are described in order to convey practical information to groups interested in constructing a similar device. The use of fiber optic hydrophones can overcome some of the limitations associated with traditional polyvinylidene difluoride (PVDF) hydrophones for calibration of acoustic fields. Compared to standard PVDF hydrophones, FOPH systems generally have larger bandwidths, enhanced spatial resolution, reduced directionality, and greater immunity to electromagnetic interference, though they can be limited by significantly lower sensitivities. The FOPH system presently described employs a 100-μm multimode optical fiber as the sensing element and incorporates a 1-W laser diode module, 2×2 optical coupler, and general-purpose 50-MHz silicon p-i-n photodetector. Wave forms generated using the FOPH system and a reference PVDF hydrophone are compared, and intrinsic and substitution methods for calibrating the FOPH system are discussed. The voltage-to-pressure transfer factor is approximately 0.8mV∕MPa (−302dBre1V∕μPa), though straightforward modifications to the optical components in the FOPH system are discussed that can significantly increase this value. Recommendations are presented to guide the choice of optical components and to provide practical insight into the routine usage of the FOPH device.
The effect of source amplitude and phase in matched field source localization
Authors: Michalopoulou Zoi-Heleni
Published: March 2006

Traditional matched field processing is typically employed for localization of a source with unknown amplitude and phase at transmission. The spectral information of the source is estimated via maximum likelihood and is used for localization with the Bartlett processor. Maximum a posteriori estimation of the spectrum of the source is here proposed along with the estimation of source location and noise variance, where the joint posterior probability distribution of all parameters is computed with Gibbs sampling. It is shown that the proposed method has a higher probability of correct localization than the traditional approach.
A hail size distribution impact transducer
Authors: Lane John E. , Youngquist Robert C. , Haskell William D. , Cox Robert B.
Published: March 2006

An active impact transducer has been designed and tested for the purpose of monitoring hail fall in the vicinity of the Space Shuttle launch pads. An important outcome of this design is the opportunity to utilize frequency analysis to discriminate between the audio signal generated from raindrop impacts and that of hailstone impacts. The sound of hail impacting a metal plate is subtly but distinctly different from the sound of rain impacts. This useful characteristic permits application of signal processing algorithms that are inherently more robust than techniques relying on amplitude processing alone in the implementation of a hail disdrometer.
Acoustic detection and classification of microchiroptera using machine learning: Lessons learned from automatic speech recognition
Authors: Skowronski Mark D. , Harris John G.
Published: March 2006

Current automatic acoustic detection and classification of microchiroptera utilize global features of individual calls (i.e., duration, bandwidth, frequency extrema), an approach that stems from expert knowledge of call sonograms. This approach parallels the acoustic phonetic paradigm of human automatic speech recognition (ASR), which relied on expert knowledge to account for variations in canonical linguistic units. ASR research eventually shifted from acoustic phonetics to machine learning, primarily because of the superior ability of machine learning to account for signal variation. To compare machine learning with conventional methods of detection and classification, nearly 3000 search-phase calls were hand labeled from recordings of five species: Pipistrellus bodenheimeri, Molossus molossus, Lasiurus borealis, L. cinereus semotus, and Tadarida brasiliensis. The hand labels were used to train two machine learning models: a Gaussian mixture model (GMM) for detection and classification and a hidden Markov model (HMM) for classification. The GMM detector produced 4% error compared to 32% error for a baseline broadband energy detector, while the GMM and HMM classifiers produced errors of 0.6±0.2% compared to 16.9±1.1% error for a baseline discriminant function analysis classifier. The experiments showed that machine learning algorithms produced errors an order of magnitude smaller than those for conventional methods.
Classification of vocalizations of killer whales using dynamic time warping
Authors: Brown Judith C. , Hodgins-Davis Andrea , Miller Patrick J. O.
Published: March 2006

A large number of killer whale sounds have recently been classified perceptually into Call Types. [A. Hodgins-Davis, thesis, Wellesley College (2004)]. The repetition rate of the pulsed component of five or more examples of each call type has been calculated using a modified form of the FFT based comb-filter method. A dissimilarity or distance matrix for these sounds was calculated using dynamic time warping to compare their melodic contours. These distances were transformed into a component space using multidimensional scaling and the resulting points were clustered with a kmeans algorithm. In grouping 57 sounds into 9 call types, a single discrepancy between the perceptual and the automated methods occurred.
Electromechanical emulation of active vibratory systems
Authors: Chen Wenyuan , Dupont Pierre E.
Published: March 2006

The design of a simple electromechanical system which is dynamically equivalent to an active vibratory system is studied in this paper. A two-step process is presented in which a passive vibratory system is first obtained, which is then modified in the second step to achieve active equivalence. Implementation of the active emulation step is achieved by closed-loop control of electromechanical shakers attached to the passive system and driven so as to generate the appropriate vibrations at the mounting locations of the active vibratory system. Experimental examples are used to demonstrate the effectiveness of this design process.
On analysis of exponentially decaying pulse signals using stochastic volatility model
Authors: Chan C. M. , Tang S. K. , Wong H.
Published: March 2006

A stochastic volatility model incorporating the exponential power distributions is adopted in the present study to analyze exponentially decaying pulses in the presence of background noises of various magnitudes. The discussions are focused on its effectiveness in the determination of the instant of the pulse initiation and the decay constant. The results are compared with those obtained by the conventional short-time Fourier transform. It is found that the present stochastic volatility model can retrieve the instant of the pulse initiation and the decay constant within engineering tolerance even when the noise is slightly stronger that the pulse amplitude. Its performance is substantially better than that of the Fourier transform when the frequency of the decay pulse fluctuates.
Elastic stiffness coefficients (c11, c33, and c13) for freshly excised and formalin-fixed myocardium from ultrasonic velocity measurements
Authors: Yang Min , Baldwin Steven L. , Marutyan Karen R. , Wallace Kirk D. , Holland Mark R. , Miller James G.
Published: March 2006

The goal of this study was to measure elastic stiffness coefficients of freshly excised and subsequently formalin-fixed myocardial tissue. Our approach was to measure the angle-dependent phase velocities associated with the propagation of a longitudinal ultrasonic wave (3–8MHz) in ovine myocardium using phase spectroscopy techniques and to interpret the results in the context of orthotropic and transversely isotropic models describing the elastic properties of myocardium. The phase velocity results together with density measurements were used to obtain the elastic stiffness coefficients c11, c33, and c13 for both symmetries. The results for the elastic stiffness coefficients c11, c33, and c13 are the same for both symmetries. Measurements for freshly excised myocardium and the same tissue after a period of formalin fixation were compared to examine the impact of fixation on the elastic stiffness coefficients.
Characteristics of nonlinear phenomena in the tonal vocalizations of a North American canid, Canis rufus
Authors: Schneider Jennifer N. , Anderson Rita E. , Miller Edward H.
Published: March 2006

This study examines the structure and frequency of occurrence of nonlinear phenomena found in tonal vocalizations produced by red wolves. Spectrograms were obtained from audio tracks of digital video recordings of captive wolves from a breeding facility in Graham, WA. Tonal vocalizations were determined to be composed of 1–30 sound units, arranged in 1–5 phrases. Linear units included squeaks (2600–9600 Hz) and wuhs (100–1600 Hz); nonlinear units accounted for 22% of sounds and included between-type frequency jumps, harmonic and pure-tone biphonations, squeaks with sidebands, and squeak jumps. Five tonal vocalization types were identified based on unit composition: squeaks (48.4%), wuhs (19.3%), and three mixed vocalizations: banded squeaks (13.2%), complex squeaks (6.4%), and squeak-wuhs (12.2%). Unit order within a squeak-wuh vocalization was not random; transitions between units following a structural gradient most likely begin with higher frequency units and end with mixed or lower frequency units. The production of nonlinear sounds varied within and between individuals. The linear and nonlinear structure of red wolf tonal vocalizations are similar to that which has been reported in dholes and African wild dogs, and which have been indicated in reviews of published sonograms of gray wolf vocalizations.
QUANTUM STATE ESTIMATION AND LARGE DEVIATIONS
Authors: KEYL M.
Published: March 2006

In this paper we propose a method to estimate the density matrix ρ of a d-level quantum system by measurements on the N-fold system in the joint state ρ⊗N. The scheme is based on covariant observables and representation theory of unitary groups and it extends previous results concerning pure states and the estimation of the spectrum of ρ. We show that it is consistent (i.e. the original input state ρ is recovered with certainty if N → ∞), analyze its large deviation behavior, and calculate explicitly the corresponding rate function which describes the exponential decrease of error probabilities in the limit N → ∞. Finally, we discuss the question whether the proposed scheme provides the fastest possible decay of error probabilities.
GENERALIZED EIGENVECTORS FOR RESONANCES IN THE FRIEDRICHS MODEL AND THEIR ASSOCIATED GAMOV VECTORS
Authors: BAUMGÄRTEL HELLMUT
Published: March 2006

A Gelfand triplet for the Hamiltonian H of the Friedrichs model on ℝ with multiplicity space [Formula: see text], [Formula: see text], is constructed such that exactly the resonances (poles of the inverse of the Livšic-matrix) are (generalized) eigenvalues of H. The corresponding eigen(anti)linear forms are calculated explicitly. Using the wave matrices for the wave (Möller) operators the corresponding eigen(anti)linear forms on the Schwartz space [Formula: see text] for the unperturbed Hamiltonian H0 are also calculated. It turns out that they are of pure Dirac type and can be characterized by their corresponding Gamov vector λ → k/(ζ0 - λ)-1, ζ0 resonance, [Formula: see text], which is uniquely determined by restriction of [Formula: see text] to [Formula: see text], where [Formula: see text] denotes the Hardy space of the upper half-plane. Simultaneously this restriction yields a truncation of the generalized evolution to the well-known decay semigroup for t ≥ 0 of the Toeplitz type on [Formula: see text]. That is: Exactly those pre-Gamov vectors λ → k/(ζ - λ)-1, ζ from the lower half-plane, [Formula: see text], have an extension to a generalized eigenvector of H if ζ is a resonance and if k is from that subspace of [Formula: see text] which is uniquely determined by its corresponding Dirac type antilinear form.