1,721,017 research outputs found
Asynchronous event-driven encoder with simultaneous temporal envelope and phase extraction for cochlear implants
No full textConventional cochlear implants using periodic sampling are power consuming and incapable of capturing the amplitude and phase of the input acoustic signal simultaneously. This paper presents an asynchronous event-driven encoder chip for cochlear implants capable of extracting the temporal fine structure. The chip architecture is based on asynchronous delta modulation (ADM) where the signal peak/trough crossing events are captured and digitized intrinsically, which has the advantages of significantly reduced power consumption, reduced circuit area, and the elimination of dedicated data compression circuitry. An 8-channel prototype chip was fabricated in 0.18 μm 1P6M CMOS process, occupying an area of 0.125 × 1.7 mm2 and has a power consumption of 36.2 μW from a 0.6V supply. A 16-channel stimulation encoding system was built by integrating two test chips, capable of processing the entire audible frequency range from 100 Hz to 10 kHz. Experimental characterization using the human voice is provided to corroborate functionality in the application environment
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Inductively-powered Implantable Integrated Circuits for Amperometric Brain Chemistry Monitoring
No full textThis dissertation presents the design of inductively-powered and powering circuits for implantable brain chemistry monitoring. It includes implantable integrated circuits designed for amperometric measurement of potassium and sodium ion concentrations, optimal design of the inductive powering links, power transfer systems, as well as the data transmission circuits to send the chip data to a nearby computer station.
To optimally power the implanted chip, a comprehensive tutorial and design guide on low-absorption inductive links is presented. The conventional model of inductive power transfer is studied from a specific-absorption-rate (SAR) point of view. The model is analyzed in an optimization problem to find the optimal geometries of the transmitting and the receiving coils that result in the highest delivered to absorbed power (in tissue) ratio. These results are then compared with the power-transfer-efficiency (PTE) optimization results, which concludes that the two are distinct.
The complete design of an inductive powering system is then presented for an in vivo free-moving animal experiment. The system offers a significantly improved power delivery to tissue absorption, a low-cost scalable architecture to cover large areas, as well as a low-cost receiver localization technique based on an impedance tracking algorithm.
To communicate data from the high-throughput implantable microarray to a benchtop receiver, a power-efficient, ultra-wideband pulse radio (UWB-IR) transmitter is presented. While the conventional UWB-IR transmitters use transient response of an LC tank, the LC tank in this design works in the steady state. This results in a significantly improved power efficiency. The resulting efficiency is comparable to those of the latest published power-efficient Bluetooth transmitters.
Finally, the implantable integrated circuits for the in vivo measurement of sodium and potassium are presented. These components include microelectrodes covered with the anti-fouling monolayer (Monoethylene glycolated (MEG) OH), ultra-low-power potentiostats, and the peripheral circuits to power, configure and operate the potentiostats. An op-amp-less-ADC design is proposed to reduce the energy consumption of the potentiostats, without compromising their sensitivity. This design allows for larger potentiostat arrays to be powered with the limited power budget of the implantable chip which enables higher spatial resolution electrochemical monitoring.Ph.D
Column-parallel 7um-pitch 2nd-order Delta-Sigma ADCs for Computational Image Sensors
No full textThis thesis presents a methodical way to integrate the full digital readout chain on-chip for computational image sensors to help lower the system complexity. A review of conventional readout architectures for image sensors is done. Next, the choice of a column-parallel 2nd-order incremental delta-sigma ADC followed by a serializer is argued for. System-level performance verification of the ADC is done in MATLAB. Circuit implementation of blocks such as integrators and quantizer are then described. Simulation results for these circuits are presented. The entire readout chain was implemented in 110 nm CMOS and characterized. An ENOB of 11.65 bits is obtained at the modulator output. The modulator consumes 475.6 uW while operating at 250 kSps. A FoMSchrier of 156 dB is achieved. Finally, a novel hardware-efficient way to integrate programmable gain within the delta-sigma modulator is also proposed, and simulation results are discussed.M.A.S
- …
