Search

Significance: Speckle noise limits the diagnostic capabilities of optical coherence tomography (OCT) images, causing both a reduction in contrast and a less accurate assessment of the microstructural morphology of the tissue. Aim: We present a speckle-noise reduction method for OCT volumes that exploits the advantages of adaptive-noise wavelet thresholding with a wavelet compounding method applied to several frames acquired from consecutive positions. The method takes advantage of the wavelet representation of the speckle statistics, calculated properly from a homogeneous sample or a region of the noisy volume. Approach: The proposed method was first compared quantitatively with different state-of-the-art approaches by being applied to three different clinical dermatological OCT volumes with three different OCT settings. The method was also applied to a public retinal spectral-domain OCT dataset to demonstrate its applicability to different imaging modalities. Results: The results based on four different metrics demonstrate that the proposed method achieved the best performance among the tested techniques in suppressing noise and preserving structural information. Conclusions: The proposed OCT denoising technique has the potential to adapt to different image OCT settings and noise environments and to improve image quality prior to clinical diagnosis based on visual assessment.

Significance: Functional near-infrared spectroscopy (fNIRS) is an increasingly popular tool in auditory research, but the range of analysis procedures employed across studies may complicate the interpretation of data. Aim: We aim to assess the impact of different analysis procedures on the morphology, detection, and lateralization of auditory responses in fNIRS. Specifically, we determine whether averaging or generalized linear model (GLM)-based analysis generates different experimental conclusions when applied to a block-protocol design. The impact of parameter selection of GLMs on detecting auditory-evoked responses was also quantified. Approach: 17 listeners were exposed to three commonly employed auditory stimuli: noise, speech, and silence. A block design, comprising sounds of 5 s duration and 10 to 20 s silent intervals, was employed. Results: Both analysis procedures generated similar response morphologies and amplitude estimates, and both indicated that responses to speech were significantly greater than to noise or silence. Neither approach indicated a significant effect of brain hemisphere on responses to speech. Methods to correct for systemic hemodynamic responses using short channels improved detection at the individual level. Conclusions: Consistent with theoretical considerations, simulations, and other experimental domains, GLM and averaging analyses generate the same group-level experimental conclusions. We release this dataset publicly for use in future development and optimization of algorithms.

Bayesian optimisation is a sample-efficient search methodology that holds great promise for accelerating drug and materials discovery programs. A frequently-overlooked modelling consideration in Bayesian optimisation strategies however, is the representation of heteroscedastic aleatoric uncertainty. In many practical applications it is desirable to identify inputs with low aleatoric noise, an example of which might be a material composition which consistently displays robust properties in response to a noisy fabrication process. In this paper, we propose a heteroscedastic Bayesian optimisation scheme capable of representing and minimising aleatoric noise across the input space. Our scheme employs a heteroscedastic Gaussian process (GP) surrogate model in conjunction with two straightforward adaptations of existing acquisition functions. First, we extend the augmented expected improvement (AEI) heuristic to the heteroscedastic setting and second, we introduce the aleatoric noise-penalised expected improvement (ANPEI) heuristic. Both methodologies are capable of penalising aleatoric noise in the suggestions and yield improved performance relative to homoscedastic Bayesian optimisation and random sampling on toy problems as well as on two real-world scientific datasets. Code is available at: \url{https://github.com/Ryan-Rhys/Heteroscedastic-BO}, Published in Machine Learning: Science and Technology 2021 (https://iopscience.iop.org/article/10.1088/2632-2153/ac298c) Earlier version accepted to the 2019 NeurIPS Workshop on Safety and Robustness in Decision Making

Purpose The aim was to study mortality due to cardiovascular disease as well as total mortality, among female industrial workers, and the association to occupational noise and shift work. Methods Women from cohorts of soft tissue paper mills (N = 3013) and pulp and paper mills (N = 1483) were merged into one cohort. Job exposure matrices were developed and used for classification of shift work and noise exposure. Every year was classified as shift work excluding nights or shift work including nights. Noise was classified into seven 5 dB(A) bins from Results Fatal myocardial infarctions (N = 144) were increased in the total cohort, SMR 1.20 (95% CI 1.01–1.41) but not total mortality. The SMR for myocardial infarction for women exposed to noise ≥ 90 dB(A) for > 10 years was 1.41 (95% CI 1.02–1.89) and for those exposed to night shifts > 10 years, 1.33 (95% CI 0.91–1.89). Shift workers without nights ≤ 65 years, with noise exposure ≥ 90 dB(A), had SMR 2.41 (95% CI 1.20–4.31) from myocardial infarction. There was no increased mortality from cerebrovascular disease. Conclusions Female paper mill workers had an increased mortality from acute myocardial infarction, especially before retirement age, when exposed to noise ≥ 90 dB(A) and with long-time employment. Exposure to shift work and noise usually occurred concurrently.

Blood flow is a parameter used to diagnose vascular diseases based on flow speed, blood pressure, and vessel size. Different techniques have been developed to estimate the relative blood flow speed and to improve the visualization of deep blood vessels; one such technique is laser speckle contrast imaging (LSCI). LSCI images contain a high level of noise mainly when deep blood vessels are imaged. To improve their visualization, several approaches for contrast computation have been developed. However, there is a compromise between noise attenuation and temporal resolution. On the one hand, spatial approaches have low spatial resolution, high temporal resolution, and significant noise attenuation, while temporal approaches have the opposite. A recent approach combines a temporal base with a directional process that allows improving the visualization of blood vessels. Nevertheless, it still contains a high level of noise and requires a high number of raw frames for its base. We propose, a space-directional approach focused on improving noise attenuation and temporal resolution for contrast computation. The results of reference approaches and the proposed one are compared quantitatively. Moreover, it is shown that the visualization of blood vessels in LSCI images can be improved by a general morphological process when the noise level is reduced.

BACKGROUND Noise exposures are associated with a host of adverse health effects, yet these exposures remain inadequately characterized in many industrial operations, including paper mills. We assessed noise at four paper mills using three measures: (i) personal noise dosimetry, (ii) area noise measurements, and (iii) questionnaire items addressing several different aspects of perceived noise exposure. METHODS We assessed exposures to noise characterized using the three measures and compared the relationships between them. We also estimated the validity of each of the three measures using a novel application of the Method of Triads, which does not appear to have been used previously in the occupational health literature. RESULTS We collected 209 valid dosimetry measurements and collected perceived noise exposure survey items from 170 workers, along with 100 area measurements. We identified exposures in excess of 85 dBA at all mills. The dosimetry and area noise measurements assigned to individual subjects generally showed good agreement, but for some operations within mill, large differences between the two measures were observed, and a substantial fraction of paired measures differed by >5 dB. Perceived noise exposures varied greatly between the mills, particularly for an item related to difficulty speaking in noise. One perceived noise exposure item related to difficulty hearing due to noise showed strong and significant correlations with both dosimetry and area measurements. The Method of Triads analysis showed that dosimetry measures had the highest estimated validity coefficient (0.70), and that the best performing perceived exposure measure had validity that exceeded that of area measurements (0.48 versus 0.40, respectively). CONCLUSIONS Workers in Swedish pulp mills have the potential for exposures to high levels of noise. Our results suggest that, while dosimetry remains the preferred approach to exposure assessment, perceived noise exposures can be used to evaluate potential exposures to noise in epidemiological studies.

598

This thesis explores the cultural history of microfilm and microphotography during the period 1900–1970, thus contributing to the broader field of research on the history of 20th century information management in the era before digital technology. The aim is to study how microfilm repeatedly, in various contexts and over time, was described and perceived as a new medium. To this end the book examines and analyses the plans, dreams and visionary prognostics put forth by various historical actors with an interest in microfilm – using case studies situated at different junctures and periods (1904–1910, 1937, 1940–1952, 1950–1970), while also ranging geographically from the United States to Europe and Sweden. From a theoretical and methodological point of view the thesis seeks to understand the historical formation of microfilm by developing the notions of configuration and reconfiguration, employing a perspective which emphasizes the continuous ontological interplay and interdependence of materiality and discourse in the formation of media. Thus, at the empirical level, the analysis takes into account realized technological materialities as well as unrealized imaginary articulations, dreams and expectations integral to the configuration of microfilm within a broader culture of paperwork. As a result of this approach the study draws on scientific texts and articles in journals, as well as newspaper reports, commercial messages, ads, handbooks and various archival documents. The analysis reveals a close relationship between microfilm and experiences of entropy connected to information systems based on paper and paperwork. It is argued that, within the dreams and plans that are studied, the most important function of microfilm was to regulate noise, decay and disorder associated with the materiality of paper – through ordering, operating on and modifying the capacities of paper media. It is also noted that microfilm was perceived and articulated as a new medium over a long period of time, even though very little changed at the technological level. From a historiographical point of view, it is thus argued, microfilm can be characterized as a simultaneously continuous and discontinuous phenomenon, taking part in a history that unfolded through repetitions, returns and non-linear steps rather than along an uninterrupted, linear path.

International audience; We present a phenomenological model for the real-time simulation of paper tearing and sound. The model uses as input rotations of the hand along with the index and thumb of left and right hands to drive the position and orientation of two regions of a sheet of paper. The motion of the hands produces a cone shaped deformation of the paper and guides the formation and growth of the tear. We create a model for the direction of the tear based on empirical observation, and add detail to the tear with a directed noise model. Furthermore, we present a procedural sound synthesis method to produce tearing sounds during interaction. We show a variety of paper tearing examples and discuss applications and limitations.

The transmission of bacteria is more likely to occur from wet skin than from dry skin; therefore, the proper drying of hands after washing should be an integral part of the hand hygiene process in health care. This article systematically reviews the research on the hygienic efficacy of different hand-drying methods. A literature search was conducted in April 2011 using the electronic databases PubMed, Scopus, and Web of Science. Search terms used were hand dryer and hand drying. The search was limited to articles published in English from January 1970 through March 2011. Twelve studies were included in the review. Hand-drying effectiveness includes the speed of drying, degree of dryness, effective removal of bacteria, and prevention of cross-contamination. This review found little agreement regarding the relative effectiveness of electric air dryers. However, most studies suggest that paper towels can dry hands efficiently, remove bacteria effectively, and cause less contamination of the washroom environment. From a hygiene viewpoint, paper towels are superior to electric air dryers. Paper towels should be recommended in locations where hygiene is paramount, such as hospitals and clinics.

The use of cervical auscultation in the evaluation of the pharyngeal swallow may become a part of the clinical evaluation of dysphagic patients. Though its use is based on subjective evaluation, an acoustic analysis of swallowing sounds might establish more objective criteria in the detection of swallowing disorders. The present study sought to investigate three aspects of the methodology for detecting swallowing sounds: (1) the type of acoustic detector unit suited to an acoustic analysis of the pharyngeal swallow, (2) the type of adhesive suited for the attachement of the detector, and (3) the optimal site for sound detection of the pharyngeal swallow. An accelerometer with double-sided paper tape was selected as the appropriate detector unit because of its wide range of frequency response and small attenuation level. Using this detector unit, swallowing sounds and noise associated with simulated laryngeal elevation and the carotid pulse were acquired at 24 sites on the neck in 14 normal subjects; these signals were acoustically analyzed. The determination of the optimal site for detecting swallowing sounds was based on the signal-to-noise ratio. The site over the lateral border of the trachea immediately inferior to the cricoid cartilage is the optimal site for detection of swallowing sounds because this site showed the greatest signal-to-noise ratio with the smallest variance. The site over the center of the cricoid cartilage and the midpoint between the site over the center of the cricoid cartilage and the site immediately superior to the jugular notch were also considered to be the most appropriate sites.

Machines employed in pulp and paper manufacturing produce high noise levels that are difficult to control. This paper presents data on noise levels both overall and in octave bands from 300 Hz through 2400 Hz in areas adjacent to such equipment with a discussion of control problems.

(1978). Noise controls for paper corrugators. American Industrial Hygiene Association Journal: Vol. 39, No. 10, pp. 824-827.