1,720,991 research outputs found
Non-Invasive sleep apnea detection using microphone technology
No full textDespite advancements in device and machine learning programs for diagnosing obstructive sleep apnea (OSA), widespread adoption is hindered by key implementation barriers, including the need for more accurate and non-invasive diagnostic tools. Various methods, such as ECG, EEG, SpO2, and respiratory signals, are used for detection, but limitations in accuracy persist. This thesis focuses on developing a machine learning algorithm using Subspace KNN classification of respiratory signals to detect different breathing patterns in individuals with and without OSA. The research also explores optimization strategies for hardware components, using Arduino and PCB boards, to enhance data collection over multiple nights. By exploring respiratory-based approaches for OSA detection, this thesis aims to provide a more targeted and specific method to detect apnea events, enhance accuracy and efficiency in detection, and contribute to the advancement of a more user-friendly and accessible solutionM.S.Includes bibliographical reference
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A bioinspired stretchable membrane-based compliance sensor
No full textCompliance sensation is a unique feature of the human skin that electronic devices could not mimic via compact and thin form-factor devices. Due to the complex nature of the sensing mechanism, up to now, only high-precision or bulky handheld devices have been used to measure compliance of materials. This also prevents the development of electronic skin that is fully capable of mimicking human skin. Here, we developed a thin sensor that consists of a strain sensor coupled to a pressure sensor and is capable of identifying compliance of touched materials. The sensor can be easily integrated into robotic systems due to its small form factor. Results showed that the sensor is capable of classifying compliance of materials with high sensitivity allowing materials with various compliance to be identified. We integrated the sensor to a robotic finger to demonstrate the capability of the sensor for robotics. Further, the arrayed sensor configuration allows a compliance mapping which can enable humanlike sensations to robotic systems when grasping objects composed of multiple materials of varying compliance. These highly tunable sensors enable robotic systems to handle more advanced and complicated tasks such as classifying touched materials.
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Development of a method to measure skin tone using a hyperspectral camera
No full textCurrent methods for quantifying skin tone lack standardization and tend to be subjective, often relying on human judgement. Research studies and clinical practice would both benefit from more consistent and objective approaches. An object’s color arises from its reflectance spectrum, which can be measured at each pixel value in an image by hyperspectral imaging. A hyperspectral camera was used to assess color samples and skin tones, examining its accuracy and precision in color measurement. A setup with broadband white light illumination was assembled with a hyperspectral camera acquiring images at 300 wavelength bands between 400-1000 nm. The system was used to image standard targets with known colorimetric values and then used to evaluate skin in human subjects. This study also compared the human perception of skin color with the hyperspectral camera’s measurements. The hyperspectral camera demonstrates a mean difference between measured and ground truth L*a*b* colors over the 24 patches of a Calibrite ColorChecker target of ΔE = 4.99. The hyperspectral camera showed lower variation (standard deviation) in human skin tone classification than a group of five human observers. This thesis serves to highlight important concepts in hyperspectral imaging and demonstrates the potential for this technology for improving methods of skin color evaluation.M.S.Includes bibliographical reference
Development of an optical imaging platform for assessment of tooth color and whiteness
No full textThe two most common devices to measure tooth color in dental applications are shade guides (a visual comparison) and colorimeters (a quantitative comparison). Shade guides are subjective, difficult to convert into a useful digital file type, and metrics cannot be easily converted to a standard color scale to quantify whiteness. Colorimeters can provide quantitative color measurements, but usually only at a single location on a sample. Digital color cameras offer the potential to achieve quantification of sample color mapped across an entire field of view but typically provide only three overlapping red / green / blue spectral channels. This project aims to create an optical imaging system using a new polarization-sensitive color camera to perform color and whiteness index measurements using the CIELAB color space. Values obtained from the camera setup were compared to measurements obtained from a commercial colorimeter (Optishade). The system was calibrated and validated using standard test objects (ColorChecker CG1 and VITA teeth), then tested using six bovine teeth which underwent staining and whitening.
After the bovine teeth were stained by immersion in coffee, there was a mean decrease in whiteness of 3.80% and mean change in L*a*b* color of 3.16% (n = 6). After whitening with a 30% hydrogen peroxide solution, there was a mean increase in whiteness of 5.98% and mean change in L*a*b* color of 4.30%, relative to tooth color after the staining experiment. The polarization camera system gave a mean relative error of 4.91% in L* value, 30.95% in a* value, and 8.21% in b* value when comparing the staining experiment results to the Optishade values. The polarization camera system gave mean relative errors of 7.57% in L* value, 20.37% in a* value, and 6.67% in b* value when comparing the post-whitening color to the Optishade values.
In summary, the methods developed in this project provide a foundation for using a new polarization-sensitive color camera for quantitative spatial mapping of tooth color and whiteness. Future studies may focus on decreasing errors in the measured L*a*b* values and using the camera’s different polarization images, which can carry information about light returning from superficial and deep layers of the tooth.M.S.Includes bibliographical reference
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