RF free ultrasonic positioning

All wearable centric location sensing technologies must address the issue of clock synchronisation between signal transmitting systems and signal receiving systems. GPS receivers, for example, compensate for synchronisation errors by incorporating a model of the receiver clock offset in the navigation solution. Drift between satellite clocks is also monitored to keep signal data in synch with GPS time. Most ultrasonic positioning systems solve the synchronisation problem by using a second medium for communication between transmitter and receiver devices. The transmitters in these systems emit RF signals (pings) to indicate the transmission of subsequent ultrasound signals (chirps). By subtracting the arrival time of the ping from that of the chirps, the receiver is able to compute the distance to each transmitter. In this paper, we describe an ultrasonic positioning system that does not use RF signals to achieve synchronisation. Instead, it exploits a periodic chirp transmission pattern to model the receiver’s position using chirp reception times exclusively. Not only does the system improve on the accuracy of previous technologies but it also eliminates bulky RF circuitry – a definite advantage for wearable applications where component size and weight are critical for usability.

Optimizing prolog for small devices: A case study

In this paper we present the design and implementation of a wearable application in Prolog. The application program is a "sound spatializer." Given an audio signal and real time data from a head-mounted compass, a signal is generated for stereo headphones that will appear to come from a position in space. We describe high-level and low-level optimizations and transformations that have been applied in order to fit this application on the wearable device. The end application operates comfortably in real-time on a wearable computer, and has a memory foot print that remains constant over time enabling it to run on continuous audio streams. Comparison with a version hand-written in C shows that the C version is no more than 20-40% faster; a small price to pay for a high level description

Textile Tools for Wearable Computing

Abstract: This paper describes the concept and application of textiles as tools, or components, for garments with wearable computing features. Evaluations of a selection of fabric swatches are presented and their suitability for use in the construction of smart textile systems. The electrical and electromagnetic properties of textiles are investigated with a fabric recommended for use as a UHF antenna, and another for thermochromatic use. The possibilities for power and signal networking are also explored. An illustrative garment using these fabrics is outlined, and opportunities for further research identified

The latest development of the DELAD project for sharing corpora of speech disorders

Corpora of speech of individuals with communication disorders (CSD) are invaluable resources for education and research, but they are costly and hard to build and difficult to share for various reasons. DELAD, which means 'shared' in Swedish, is a project initiated by Professors Nicole Muller and Martin Ball in 2015 that aims to address this issue by establishing a platform for researchers to share datasets of speech disorders with interested audiences. To date four workshops have been held, where selected participants, covering various expertise including researchers in clinical phonetics and linguistics, speech and language therapy, infrastructure specialists, and ethics and legal specialists, participated to discuss relevant issues in setting up such an archive. Positive and steady progress has been made since 2015, including refurbishing the DELAD website (http://delad.net/) with information and application forms for researchers to join and share their datasets and linking with the CLARIN K-Centre for Atypical Communication Expertise (https://ace.ruhosting.nl/) where CSD can be hosted and accessed through the CLARIN B-Centres, The Language Archive (https://tla.mpi.nl/tools/tla-tools/) and TalkBank (https://talkbank.org/). The latest workshop, which was funded by CLARIN (Common Language Resources and Technology Infrastructure) was held as an online event in January 2021 on topics including Data Protection Impact Assessments, reviewing changes in ethics perspectives in academia on sharing CSD, and voice conversion as a mean to pseudonomise speech. This paper reports the latest progress of DELAD and discusses the directions for further advance of the initiative, with information on how researchers can contribute to the repository.Peer reviewe

High-level languages for small devices: A case study

In this paper we study, through a concrete case, the feasibility of using a high-level, general-purpose logic language in the design and implementation of applications targeting wearable computers. The case study is a "sound spatializer" which, given real-time signáis for monaural audio and heading, generates stereo sound which appears to come from a position in space. The use of advanced compile-time transformations and optimizations made it possible to execute code written in a clear style without efñciency or architectural concerns on the target device, while meeting strict existing time and memory constraints. The final executable compares favorably with a similar implementation written in C. We believe that this case is representative of a wider class of common pervasive computing applications, and that the techniques we show here can be put to good use in a range of scenarios. This points to the possibility of applying high-level languages, with their associated flexibility, conciseness, ability to be automatically parallelized, sophisticated compile-time tools for analysis and verification, etc., to the embedded systems field without paying an unnecessary performance penalty

Toothy craniopharyngioma : a literature review and case report of craniopharyngioma with extensive odontogenic differentiation and tooth formation

No abstract available.http://www.springerlink.com/content/100510

Acoustic sizing of an ultrasound contrast agent

Because the properties of ultrasound contrast agent populations after administration to patients are largely unknown, methods able to study them noninvasively are required. In this study, we acoustically performed a size distribution measurement of the ultrasound contrast agent Definity®. Single lipid-shelled microbubbles were insonified at 25 MHz, which is considerably higher than their resonance frequency, so that their acoustic responses depended on their geometrical cross sections only. We calculated the size of each microbubble from their measured backscattered pressures. The acoustic size measurements were compared with optical reference size measurements to test their accuracy. Our acoustic sizing method was applied to 88 individual Definity® bubbles to derive a size distribution of this agent. The size distribution obtained acoustically showed a mean diameter (2.5 μm) and a standard deviation (0.9 μm) in agreement within 8% with the optical reference measurement. At 25 MHz, this method can be applied to bubble sizes larger than 1.2 μm in diameter. It was observed that similar sized bubbles can give different responses (up to a factor 1.5), probably because of shell differences. These limitations should be taken into account when implementing the method in vivo. This acoustic sizing method has potential for estimating the size distribution of an ultrasound contrast agent noninvasivel