Blood Pressure Measurement Device for Low Resource Settings

ME450 Capstone Design and Manufacturing Experience: Fall 2015The design team spent eight weeks in the Obstetrics and Gynecology Department at a tertiary referral hospital, Komfo Anokye Teaching Hospital (KATH), in Kumasi, Ghana. During the team’s immersion experience at the hospital, the team observed healthcare providers experiencing difficulty following obstetrics patients’ blood pressure management plans. This occurred largely because of the high volume of patients and the busyness of the wards. The patient's blood pressure measurement strongly influences the treatment especially if she has hypertensive disorders. Hypertensive disorders, mainly preeclampsia and eclampsia, are the second leading cause of maternal mortality worldwide and the leading cause of maternal mortality at KATH. The team identified an opportunity for the development of a blood pressure measurement device to aid the healthcare providers in measuring the patients’ blood pressures every 30 minutes or four hours according to their management plans. This project is in collaboration with clinical mentors and advisors at University of Michigan Hospital and KATH. The final design is an auscultatory device with a microphone stethoscope and headphones to listen to the Korotkoff sounds, a hand pump for manual inflation, an automatic constant rate deflation facilitated by a solenoid valve, a LCD screen to display the current pressure, a slip-on cuff, an aneroid pressure gauge for calibration, a handle, a storage area, and a rechargeable battery. The current prototype follows the design fairly closely however the device is not powered by a rechargeable battery and the electrical components are all on a breadboard which prevents its portability. All validation testing completed so far on the current prototype has been promising including testing the accuracy and ease-of-use of the device when used by three nursing student. This device will be continued to be improved next semester so that it can be taken to KATH for further validation and feedback.http://deepblue.lib.umich.edu/bitstream/2027.42/117349/1/ME450-F15-Project07-FinalReport.pd

Non-speech auditory output

No abstract available

Blind Direct Walking Distance Judgment Research: A Best Practices Guide

Over the last 30 years, Virtual Reality (VR) research has shown that distance perception in VR is compressed as compared to the real world. The full reason for this is yet unknown. Though many experiments have been run to study the underlying reasons for this compression, often with similar procedures, the experimental details either show significant variation between experiments or go unreported. This makes it difficult to accurately repeat or compare experiments, as well as negatively impacts new researchers trying to learn and follow current best practices. In this paper, we present a review of past research and things that are typically left unreported. Using this and the practices of my advisor as evidence, we suggest a standard to assist researchers in performing quality research pertaining to blind direct walking distance judgments in VR

DEVELOPMENT OF AN IMPROVED TIME VARYING LOUDNESS MODEL WITH THE INCLUSION OF BINAURAL LOUDNESS SUMMATION

As the perceived quality of a product is becoming more important in the manufacturing industry, more emphasis is being placed on accurately predicting the sound quality of everyday objects. This study was undertaken to improve upon current prediction techniques with regard to the psychoacoustic descriptor of loudness and an improved binaural summation technique. The feasibility of this project was first investigated through a loudness matching experiment involving thirty-one subjects and pure tones of constant sound pressure level. A dependence of binaural summation on frequency was observed which had previously not been a subject of investigation in the reviewed literature. A follow-up investigation was carried out with forty-eight volunteers and pure tones of constant sensation level. Contrary to existing theories in literature the resulting loudness matches revealed an amplitude versus frequency relationship which confirmed the perceived increase in loudness when a signal was presented to both ears simultaneously as opposed to one ear alone. The resulting trend strongly indicated that the higher the frequency of the presented signal, the greater the increase in observed binaural summation. The results from each investigation were summarized into a single binaural summation algorithm and inserted into an improved time-varying loudness model. Using experimental techniques, it was demonstrated that the updated binaural summation algorithm was a considerable improvement over the state of the art approach for predicting the perceived binaural loudness. The improved function retained the ease of use from the original model while additionally providing accurate estimates of diotic listening conditions from monaural WAV files. It was clearly demonstrated using a validation jury test that the revised time-varying loudness model was a significant improvement over the previously standardized approach

National Health and Nutrition Examination Survey : audiometry procedures manual

The National Center for Health Statistics (NCHS) has regularly included evaluations of the auditory system in its health examination surveys. These evaluations have included one or more of the following: a brief medical examination of the ear, interview questions regarding hearing ability and ear diseases, tympanometry (a test of middle ear function), pure tone air conduction thresholds, pure tone bone conduction thresholds, and/or speech discrimination testing. Sometimes these evaluations were done on all NHANES examinees, and some surveys included hearing evaluations on only a subset of examinees (such as children or adults).au.pd

Augmented Reality Audio Applications in Outdoor Use

Lisätyksi audiotodellisuudeksi (LAT) kutsutaan todellista äänimaisemaa, johon on lisätty virtuaalisia ääniobjekteja. Käyttäjän kuulema ääni tallenetaan LAT-kuulokkeisiin integroiduilla miniatyyrimikrofoneilla ja toistetaan tämän jälkeen suoraan käyttäjän korviin. Nauhoitetun signaalin päälle käyttäjälle voidaan toistaa keinotekoista tai aikaisemmin nauhoitettua signaalia. Binauraalisella prosessoinnilla lisätyt, virtuaaliset, äänilähteet voidaan sijoittaa haluttuun suuntaan. Virtuaaliset äänilähteet voidaan sitoa todelliseen äänikenttään binauraalisella prosessoinnilla, jos käyttäjän sijainti ja orientaatio tunnetaan. Käyttäjän jäljittämiseen käytettyjen menetelmien rajoituksista johtuen aikaisemmin toteutetut LAT-sovellutukset on tarkoitettu vain sisäkäyttöön. Tämän diplomityön tavoitteena oli suunnitella ja toteuttaa alusta ulkona käytettäviä LAT-sovellutuksia varten. Sekä inertiaan että maan magneettikenttään perustuvia menetelmiä käytettiin käyttäjän orientaation ja satelliittipaikannusta (GPS) paikan määrittämiseen. Alustan toimivuuden osoittamiseksi toteutettiin äänimuistisovellus suunnitellulla alustalla. Äänimuistia käytetään tallentamaan kaikki käyttäjän kuulema ääni, paikka- ja orientaatiotiedolla laajennettuna. Paikka- ja orientaatiotieto tallennettiin metatietona äänitiedostoon uudessa Ara-Wav formaatissa, jotta tietoa voidaan käsitellä myöhemminkin. Äänimuistisovellusta testattiin ja analysoitiin, minkä pohjalta alusta todettiin toimivaksi lähtökohdaksi ulkokäyttöön tarkoitettujen LAT-sovellusten toteuttamiseen.Augmented Reality Audio (ARA) can be defined as the real audio environment augmented with virtual sound objects. Everything the user hears is recorded with miniature microphones integrated in the ARA headset earphones. The recorded audio is immediately played back directly to the ears of the user. Along with the recorded signal, artificial or previously recorded sounds can be added. Binaural processing is used to position the virtual sounds in certain directions related to the user. The virtual sound sources can be fixed to the real environment with binaural processing, if the position and orientation of the user are known. Several ARA applications have been implemented before, but so far only to be used indoors, because of the limitations of applied tracking methods. The goal of the thesis was to design and implement a platform to be used outdoors. Inertial and magnetic tracking were used together to track the orientation of the user, and Global Positioning System (GPS) was used for position tracking. As a proof of concept, the Audiomemo application was implemented on the platform. Audiomemo can be used to record everything the user hears, and to enable the user to browse through previously recorded audio memories. The orientation and position information is saved as metadata in the audio file to enable retrieval of the information afterwards. The Audiomemo application was preliminarily tested and analyzed. The platform was found functional and a useful working base for ARA applications in outdoor use

Spatial auditory display for acoustics and music collections

PhDThis thesis explores how audio can be better incorporated into how people access information and does so by developing approaches for creating three-dimensional audio environments with low processing demands. This is done by investigating three research questions. Mobile applications have processor and memory requirements that restrict the number of concurrent static or moving sound sources that can be rendered with binaural audio. Is there a more e cient approach that is as perceptually accurate as the traditional method? This thesis concludes that virtual Ambisonics is an ef cient and accurate means to render a binaural auditory display consisting of noise signals placed on the horizontal plane without head tracking. Virtual Ambisonics is then more e cient than convolution of HRTFs if more than two sound sources are concurrently rendered or if movement of the sources or head tracking is implemented. Complex acoustics models require signi cant amounts of memory and processing. If the memory and processor loads for a model are too large for a particular device, that model cannot be interactive in real-time. What steps can be taken to allow a complex room model to be interactive by using less memory and decreasing the computational load? This thesis presents a new reverberation model based on hybrid reverberation which uses a collection of B-format IRs. A new metric for determining the mixing time of a room is developed and interpolation between early re ections is investigated. Though hybrid reverberation typically uses a recursive lter such as a FDN for the late reverberation, an average late reverberation tail is instead synthesised for convolution reverberation. Commercial interfaces for music search and discovery use little aural information even though the information being sought is audio. How can audio be used in interfaces for music search and discovery? This thesis looks at 20 interfaces and determines that several themes emerge from past interfaces. These include using a two or three-dimensional space to explore a music collection, allowing concurrent playback of multiple sources, and tools such as auras to control how much information is presented. A new interface, the amblr, is developed because virtual two-dimensional spaces populated by music have been a common approach, but not yet a perfected one. The amblr is also interpreted as an art installation which was visited by approximately 1000 people over 5 days. The installation maps the virtual space created by the amblr to a physical space

Design, modeling and analysis of object localization through acoustical signals for cognitive electronic travel aid for blind people

El objetivo de la tesis consiste en el estudio y análisis de la localización de objetos en el entorno real mediante sonidos, así como la posterior integración y ensayo de un dispositivo real basado en tal técnica y destinado a personas con discapacidad visual. Con el propósito de poder comprender y analizar la localización de objetos se ha realizado un profundo estado de arte sobre los Sistemas de Navegación desarrollados durante las últimas décadas y orientados a personas con distintos grados de discapacidad visual. En el citado estado del arte, se han analizado y estructurado los dispositivos de navegación existentes, clasificándolos de acuerdo con los componentes de adquisición de datos del entorno utilizados. A este respecto, hay que señalar que, hasta el momento, se conocen tres clases de dispositivos de navegación: 'detectores de obstáculos', que se basan en dispositivos de ultrasonidos y sensores instalados en los dispositivos electrónicos de navegación con el objetivo de detectar los objetos que aparecen en el área de trabajo del sistema; 'sensores del entorno' - que tienen como objetivo la detección del objeto y del usuario. Esta clase de dispositivos se instalan en las estaciones de autobús, metro, tren, pasos de peatones etc., de forma que cuando el sensor del usuario penetra en el área de alcance de los sensores instalados en la estación, éstos informan al usuario sobre la presencia de la misma. Asimismo, el sensor del usuario detecta también los medios de transporte que tienen instalado el correspondiente dispositivo basado en láser o ultrasonidos, ofreciendo al usuario información relativa a número de autobús, ruta etc La tercera clase de sistemas electrónicos de navegación son los 'dispositivos de navegación'. Estos elementos se basan en dispositivos GPS, indicando al usuario tanto su locación, como la ruta que debe seguir para llegar a su punto de destino. Tras la primera etapa de elaboración del estaDunai ., L. (2010). Design, modeling and analysis of object localization through acoustical signals for cognitive electronic travel aid for blind people [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8441Palanci