1,720,958 research outputs found
Development of a Magnetostrictive Thick-Film Material for MEMS Devices
No full textThis paper presents research being carried out at the University of Southampton into the development of a magnetostrictive thick-film material, intended for use as an actuator with MEMS devices. This magnetostrictive thick-film material has been deposited onot alumina substrates, and this paper presents work on migrating the technology onto silicon and the evaluation of the resulting magnetostrictive thick-films
A design study of a wireless power transfer system for use to transfer energy from a vibration energy harvester
No full textA wirelessly powered remote sensor node is presented along with its design process. The purpose of the node is the further expansion of the sensing capabilities of the commercial Perpetuum system used for condition monitoring on trains and rolling stock which operates using vibration energy harvesting. Surplus harvested vibration energy is transferred wirelessly to a remote satellite sensor to allow measurements over a wider area to be made. This additional data is to be used for long term condition monitoring. Performance measurements made on the prototype remote sensor node are reported and advantages and disadvantages of using the same RF frequency for power and data transfer are identified
Review of the application of energy harvesting in buildings
No full textThis review presents the state of the art of the application of energy harvesting in commercial and residential buildings. Electromagnetic (optical and radio frequency), kinetic, thermal and airflow-based energy sources are identified as potential energy sources within buildings and the available energy is measured in a range of buildings. Suitable energy harvesters are discussed and the available and the potential harvested energy calculated. Calculations based on these measurements, and the technical specifications of state-of-the-art harvesters, show that typical harvested powers are: (1) indoor solar cell (active area of 9 cm 2 , volume of 2.88 cm 3 ): â
Evaluation of otoacoustic emissions as a biometric
No full textThis paper presents a comprehensive overview of an investigation into the use of Otoacoustic Emissions (OAE) as an identification biometric. OAE could be important as a biometric identifier in applications where users wear headsets since it is discrete and difficult to spoof. OAE are very low level (~17 dB Sound Pressure Level (SPL)) sounds emitted from the human ear as part of the normal hearing process. They can occur spontaneously or be invoked by a suitable stimulus, these being known as Transient Evoked Otoacoustic Emissions (TEOAE) and Distortion Product Otoacoustic Emission (DPOAE). An initial visual comparison shows that otoacoustic emissions are clearly distinctive and are stable over a six month period. A biometric analysis based on the Euclidean distance measurement of TEOAE recordings in the temporal domain was performed on pre-recorded datasets captured for medical purposes and data were collected specifically for this study. For a database of 23 subjects, the predicted Equal Error Rate (EER) was 1.24% for a 90% confidence interval. DPOAEs also demonstrated biometric potential but the level of discrimination is inferior to TEOAE. The combination of DPOAE and TEOAE into a multimodal analysis was demonstrated to be feasible although the potential improvement in performance is yet to be quantified. Finally the use of Maximum Length Sequencing (MLS) was investigated to reduce capture time without decreasing performance. This demonstrated a reduction in capture time for a TEOAE from 1 minute to 5 seconds with a visual analysis of a 4th order MLS showing good stability and reproducibility. OAEs can potentially be used as a biometric and benefit from their small template size (512 data points in our TEOAE biometric) and simple analysis. The level of background noise is the most significant practical factor that affects biometric performance
Design and construction of a micro-milled fluidic device as part of a DNA biosensor
No full textUnder the Optonanogen project (EU contract IST-2001237239), a novel biosensor has been developed, which incorporates a disposable acrylic (PMMA) fluidic header [1]. This biosensor relies on a micro-cantilever array which is etched into a silicon chip and contained within the header. Nucleic acids are immobilised on one side of each of the 20 cantilevers, then upon injection of a biological sample over the cantilevers, hybridisation of DNA contained within the sample (and complementary to the immobilised nucleic acids) generates surface stresses on the cantilever and causes bending. The cantilever deflection is then detected optically using laser and micro-lens arrays. The sensor was initially designed to detect human gene mutations, particularly those associated with breast cancer, and miniaturises this form of diagnostic test [2]. This paper, however, concentrates on the fluidic design of the header, its ease of use and the ability to deliver the test sample to the cantilevers
A comparison of verification in the temporal and cepstrum-transformed domains of transient evoked otoacoustic emissions for biometric identification
Full text linkAn investigation of methods for the use of Transient Evoked Otoacoustic Emissions (TEOAE) as an identification biometric is described in this paper. The results build upon advances in the field of otoacoustics to show that otoacoustic emissions are clearly distinctive and, hence, can be utilized as an identification biometric. Three contending methods of analysis to calculate the Euclidean distance separating individuals are described which are: Interpretation of the area-under-the-curve information from the time series TEOAE data; A measurement of the distance between a TEOAE recording in the temporal domain and a user template based upon averaging prior recorded data; A measurement of the distance between a TEOAE recording transformed into the cepstral domain and a user template based upon averaging cepstral transformed prior recorded data. False acception and rejection rates are given for the above techniques when applied to sets of test data recorded from test groups. In this study the best performance has been achieved using an Euclidian distance analysis in the temporal domain, which has yielded a false accept rate (FAR) of 1.27% and a false rejection rate (FRR) of 0 when applied to a data set consisting of a total of 230 recordings from 23 different subjects. <br/
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
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