Publications by authors named "Craig Jin"

Introduction: Over the past decade, several machine learning (ML) algorithms have been investigated to assess their efficacy in detecting voice disorders. Literature indicates that ML algorithms can detect voice disorders with high accuracy. This suggests that ML has the potential to assist clinicians in the analysis and treatment outcome evaluation of voice disorders.

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Wearable smart glasses are an emerging technology gaining popularity in the assistive technologies industry. Smart glasses aids typically leverage computer vision and other sensory information to translate the wearer's surrounding into computer-synthesized speech. In this work, we explored the potential of a new technique known as "acoustic touch" to provide a wearable spatial audio solution for assisting people who are blind in finding objects.

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When a broadband source of radiated noise transits past a fixed hydrophone, a Lloyd's mirror constructive/destructive interference pattern can be observed in the output spectrogram. By taking the spectrum of a (log) spectrum, the power cepstrum detects the periodic structure of the Lloyd's mirror fringe pattern by generating a sequence of pulses located at the fundamental quefrency and its multiples. The fundamental quefrency, which is the reciprocal of the frequency difference between adjacent destructive interference fringes, equates to the multipath delay time.

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While ultrasound is most widely known for its use in diagnostic imaging, the energy carried by ultrasound waves can be utilized to influence cell function and drug delivery. Consequently, our ability to use ultrasound energy at a given intensity unlocks the opportunity to use the ultrasound for therapeutic applications. Indeed, in the last decade ultrasound-based therapies have emerged with promising treatment modalities for several medical conditions.

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The Open-electroencephalography (EEG) framework is a popular platform to enable EEG measurements and general purposes Brain Computer Interface experimentations. However, the current platform is limited by the number of available channels and electrode compatibility. In this paper we present a fully configurable platform with up to 32 EEG channels and compatibility with virtually any kind of passive electrodes including textile, rubber and contactless electrodes.

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Under-nutrition in neonates can cause immediate mortality, impaired cognitive development and early onset adult disease. Body fat percentage measured using air-displacement-plethysmography has been found to better indicate under-nutrition than conventional birth weight percentiles. However, air-displacement-plethysmography equipment is expensive and non-portable, so is not suited for use in developing communities where the burden is often the greatest.

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Recent studies have shown high correlation between pulmonary perfusion mapping with impedance contrast enhanced Electrical Impedance Tomography (EIT) and standard perfusion imaging methods such as Computed Tomography (CT) and Single Photon Emission Computerized Tomography (SPECT). EIT has many advantages over standard imaging methods as it is highly portable and non-invasive. Contrast enhanced EIT uses hypertonic saline bolus instead of nephrotoxic contrast medium that are utilized by CT and nuclear Ventilation/Perfusion (V/Q) scans.

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Manual measurements of small changes in retinal vascular diameter are slow and may be subject to considerable observer-related biases. Among the conventional automatic methods the sliding linear regression filter (SLRF) demonstrates the least scattered and most repeatable coefficients. For optimal performance it relies on the choice of the correct filter scale for different vessel sizes.

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We present a bio-potential front-end capable of recording unipolar ECG leads without making use of the Wilson central terminal (WCT). The information contained in the new unipolar recordings may yield unique diagnostic information as it avoids the need to essentially subtract data or make use of the averaging effect imposed by the WCT. The system also allows a direct, real-time software calculation of signals corresponding to standard ECG leads for standard diagnosis.

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Feedback plays an important role when learning to use a brain computer interface (BCI), particularly in the case of synchronous feedback that relies on the interaction subject. In this preliminary study, we investigate the role of combined auditory-visual feedback during synchronous μ rhythm-based BCI sessions to help the subject to remain focused on the selected imaginary task. This new combined feedback, now integrated within the general purpose BCI2000 software, has been tested on eight untrained and three trained subjects during a monodimensional left-right control task.

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Background: Pregnancy testing in cattle is commonly invasive requiring manual rectal palpation of the reproductive tract that presents risks to the operator and pregnancy. Alternative non-invasive tests have been developed but have not gained popularity due to poor specificity, sensitivity and the inconvenience of sample handling. Our aim is to present the pilot study and proof of concept of a new non invasive technique to sense the presence and age (limited to the closest trimester of pregnancy) of the foetus by recording the electrical and audio signals produced by the foetus heartbeat using an array of specialized sensors embedded in a stand alone handheld prototype device.

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Electrode contact impedance is a crucial factor in physiological measurements and can be an accuracy-limiting factor when performing electroencephalography and electrical impedance tomography. In this work, standard flat electrodes and micromachined multipoint spiked electrodes are characterized with a finite-element method electromagnetic solver and the dependence of the contact impedance on geometrical factors is explored. It is found that flat electrodes are sensitive to changes in the outer skin layer properties related to hydration and thickness, while spike electrodes are not.

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This paper presents the first robotic system featuring audio-visual (AV) sensor fusion with neuromorphic sensors. We combine a pair of silicon cochleae and a silicon retina on a robotic platform to allow the robot to learn sound localization through self motion and visual feedback, using an adaptive ITD-based sound localization algorithm. After training, the robot can localize sound sources (white or pink noise) in a reverberant environment with an RMS error of 4-5° in azimuth.

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The design and construction of a circular microphone array (CMA) that has a wide frequency range suitable for human hearing is presented. The design of the CMA was achieved using a technique based on simulated directivity index (DI) curves. The simulated DI curves encapsulate the critical microphone array performance limitations: spatial aliasing, measurement noise, and microphone placement errors.

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Cost reduction has become the primary theme of healthcare reforms globally. More providers are moving towards remote patient monitoring, which reduces the length of hospital stays and frees up their physicians and nurses for acute cases and helps them to tackle staff shortages. Physiological sensors are commonly used in many human specialties e.

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A neuromorphic sound localization system is presented. It employs two microphones and a pair of silicon cochleae with address event interface for front-end processing. The system is based the extraction of interaural time difference from a far-field source.

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As wireless bio-medical long term monitoring moves towards personal monitoring it demands very high input impedance systems capable to extend the reading of bio-signal during the daily activities offering a kind of "stress free", convenient connection, with no need for skin preparation. In particular we highlight the development and broad applications of our own circuits for wearable bio-potential sensor systems enabled by the use of an FET based amplifier circuit with sufficiently high impedance to allow the use of passive dry electrodes which overcome the significant barrier of gel based contacts. In this paper we present the ability of dry electrodes in long term monitoring of ECG, EEG and fetal ECG.

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Electrical Impedance Tomography (EIT) calculates the internal conductivity distribution within a body using electrical contact measurements. Conventional EIT reconstruction methods solve a linear model by minimizing the least squares error, i.e.

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Objective: We present a new, low power EEG recording system with an ultra-high input impedance that enables the use of long-lasting, passive dry electrodes. It incorporates Bluetooth wireless connectivity and is designed to be suitable for long-term monitoring during daily activities.

Methods: The new EEG system is compared to a standard and clinically available reference EEG system using wet electrodes in three separate sets of experiments.

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We present a new, low-power electrocardiogram (ECG) recording system with an ultra-high input impedance that enables the use of long-lasting, dry electrodes. The system incorporates a low-power Bluetooth module for wireless connectivity and is designed to be suitable for long-term monitoring during daily activities. The new system using dry electrodes was compared with a clinically approved ECG reference system using gelled Ag/AgCl electrodes and performance was found to be equivalent.

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To study the spatial hearing abilities of bilateral hearing-aid users in multi-talker situations, 20 subjects received fittings configured to preserve acoustic cues salient for spatial hearing. Following acclimatization, speech reception thresholds (SRTs) were measured for three competing talkers that were either co-located or spatially separated along the front-back or left-right dimension. In addition, the subjects' working memory and attentional abilities were measured.

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A method for synthesizing near-field head-related transfer functions (HRTFs) from far-field HRTFs measured using an acoustic point-source of sound is presented. Near-field HRTFs are synthesized by applying an analytic function describing the change in the transfer function when the location of a sound source changes from the far-field to the near-field: the distance variation function (DVF). The DVF is calculated from a rigid sphere model and approximates the change in the frequency-dependent interaural level cues as a function of the change in sound source distance.

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We present a first-order nonhomogeneous Markov model for the interspike-interval density of a continuously stimulated spiking neuron. The model allows the conditional interspike-interval density and the stationary interspike-interval density to be expressed as products of two separate functions, one of which describes only the neuron characteristics and the other of which describes only the signal characteristics. The approximation shows particularly clearly that signal autocorrelations and cross-correlations arise as natural features of the interspike-interval density and are particularly clear for small signals and moderate noise.

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Phonotaxis is the ability to orient towards or away from sound sources. Crickets can locate conspecifics by phonotaxis to the calling (mating) song they produce, and can evade bats by negative phonotaxis from echolocation calls. The behaviour and underlying physiology have been studied in some depth, and the auditory system solves this complex problem in a unique manner.

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This study measured the accuracy with which human listeners can localize spoken words. A broadband (300 Hz-16 kHz) corpus of monosyllabic words was created and presented tolisteners using a virtual auditory environment. Localization was examined for 76 locations ona sphere surrounding the listener.

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