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Eveleigh, Australia

Chen S.,University of New South Wales | Epps J.,University of New South Wales | Chen F.,ATP Research Laboratory
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2013

Using the task-evoked pupillary response (TEPR) to index cognitive load can contribute significantly to the assessment of memory function and cognitive skills in patients. However, the measurement of pupillary response is currently limited to a well-controlled lab environment due to light reflex and also relies heavily on expensive video-based eye trackers. Furthermore, commercial eye trackers are usually dedicated to gaze direction measurement, and their calibration procedure and computing resource are largely redundant for pupil-based cognitive load measurement (PCLM). In this study, we investigate the validity of cognitive load measurement with (i) pupil light reflex in a less controlled luminance background; (ii) a low-cost infrared (IR) webcam for the TEPR in a controlled luminance background. ANOVA results show that with an appropriate baseline selection and subtraction, the light reflex is significantly reduced, suggesting the possibility of less constrained practical applications of PCLM. Compared with the TEPR from a commercial remote eye tracker, a low-cost IR webcam achieved a similar TEPR pattern and no significant difference was found between the two devices in terms of cognitive load measurement across five induced load levels. © 2013 IEEE.

Felic G.,University of Melbourne | Thomas C.,ATP Research Laboratory | Skafidas E.,University of Melbourne
IET Microwaves, Antennas and Propagation | Year: 2011

In this study, an antenna design technique that includes wire bond interconnection for 60-GHz antenna-chip integration is investigated. The presented technique is unique as it does not require additional matching elements to deal with wire bond interconnection effects on the antenna input impedance matching bandwidth. As the reactance of the bonding wires is compensated by design of the antenna circuit, the matching bandwidth is not significantly reduced. To the authors' knowledge, this is the first antenna design presented for integration with a 60-GHz CMOS chip using wire bond interconnection without a compensation network. © 2011 The Institution of Engineering and Technology.

Hsu B.-W.,National Tsing Hua University | Wang M.-J.J.,National Tsing Hua University | Chen C.-Y.,National Tsing Hua University | Chen F.,ATP Research Laboratory
Perceptual and Motor Skills | Year: 2015

This study identified several physiological indices that can accurately monitor mental workload while participants performed multiple tasks with the strategy of maintaining stable performance and maximizing accuracy. Thirty male participants completed three 10-min. simulated multitasks: MATB (Multi-Attribute Task Battery) with three workload levels. Twenty-five commonly used mental workload measures were collected, including heart rate, 12 HRV (heart rate variability), 10 EEG (electroencephalography) indices (α, β, θ, α/θ, θ/β from O1-O2 and F4-C4), and two subjective measures. Analyses of index sensitivity showed that two EEG indices, θ and α/θ (F4-C4), one time-domain HRV-SDNN (standard deviation of inter-beat intervals), and four frequency-domain HRV: VLF (very low frequency), LF (low frequency), %HF (percentage of high frequency), and LF/HF were sensitive to differentiate high workload. EEG α/θ (F4-C4) and LF/HF were most effective for monitoring high mental workload. LF/HF showed the highest correlations with other physiological indices. EEG α/θ (F4-C4) showed strong correlations with subjective measures across different mental workload levels. Operation strategy would affect the sensitivity of EEG α (F4-C4) and HF. © Perceptual & Motor Skills 2015.

Chen S.,University of New South Wales | Chen S.,ATP Research Laboratory | Epps J.,University of New South Wales | Epps J.,ATP Research Laboratory
IEEE Transactions on Cybernetics | Year: 2014

Monitoring pupil and blink dynamics has applications in cognitive load measurement during human-machine interaction. However, accurate, efficient, and robust pupil size and blink estimation pose significant challenges to the efficacy of real-time applications due to the variability of eye images, hence to date, require manual intervention for fine tuning of parameters. In this paper, a novel self-tuning threshold method, which is applicable to any infrared-illuminated eye images without a tuning parameter, is proposed for segmenting the pupil from the background images recorded by a low cost webcam placed near the eye. A convex hull and a dual-ellipse fitting method are also proposed to select pupil boundary points and to detect the eyelid occlusion state. Experimental results on a realistic video dataset show that the measurement accuracy using the proposed methods is higher than that of widely used manually tuned parameter methods or fixed parameter methods. Importantly, it demonstrates convenience and robustness for an accurate and fast estimate of eye activity in the presence of variations due to different users, task types, load, and environments. Cognitive load measurement in human-machine interaction can benefit from this computationally efficient implementation without requiring a threshold calibration beforehand. Thus, one can envisage a mini IR camera embedded in a lightweight glasses frame, like Google Glass, for convenient applications of real-time adaptive aiding and task management in the future. © 2014 IEEE.

Bhowmik K.,University of New South Wales | Bhowmik K.,ATP Research Laboratory | Peng G.-D.,University of New South Wales | Luo Y.,University of New South Wales | And 5 more authors.
Journal of Lightwave Technology | Year: 2015

The intrinsic hydrostatic pressure sensitivity of polymer optical fiber Bragg grating (POFBG) with different diameters are investigated. POFBGs are inscribed in single-mode polymer fiber and etched down to different diameters. We have experimentally demonstrated that the material properties of the polymer optical fiber can change after etching and thus the etching procedure can have an impact on the pressure sensitivity of the POFBG. It is observed from the experimental results that hydrostatic pressure induces a positive wavelength shift to the POFBG and the pressure sensitivity of the POFBG shows significant increase as the fiber diameter reduces through etching. A pressure sensitivity of 0.20 pm/kPa is obtained for an unetched POFBG while for an etched POFBG with 55-μm diameter a sensitivity of 0.75 pm/kPa is observed. Temperature compensation techniques are also successfully implemented to extract the true intrinsic pressure sensitivity of the POFBG. Through this study, the intrinsic pressure sensitivity of POFBG with different diameters are obtained and also the significance of etching and its impact on pressure sensitivity is demonstrated. This information can lead to further research and development on high sensitivity pressure transducers based on etched POFBGs. © 2014 IEEE.

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