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A head-mounted active noise control (ANC) system based on the single-channel ( $1\times 1 \times 1$ ) feedforward control has been studied as a noise reduction method in complicated noise environments such as factories in which various machines are located that generate unwanted noises. However, it is difficult to reduce the noise arriving from various directions because the causality constraint cannot be satisfied. To solve this problem, we developed a head-mounted ANC system based on the multi-channel ( $2\times 1 \times 1$ ) feedforward control. This ANC system has two reference microphones that satisfy the causality constraint. Therefore, the proposed head-mounted ANC system achieves the expansion of noise reducible range of 0-100° compared to that of the conventional head-mounted ANC with the range of 0-60°. In this paper, we examine the effectiveness of the newly developed head-mounted ANC system. In the experiments, we evaluate the effectiveness of placing two reference microphones on noise reduction performance in the case of various arrival direction of the unwanted noise. Experimental results demonstrate that the proposed system increases the noise reducible range and improves the noise reduction performance for two noise sources. In addition, we theoretically prove the effectiveness of the proposed system.

A field-programmable gate array (FPGA) high-resolution time-to-digital converter (TDC) based on phase-wrapping, sorting, and selection to achieve an extremely fine bin size of 1 ps is proposed in this paper. Based on Nutt interpolation method, a wide measurement range with a high resolution can be realized at the same time. The input signal is fed into tapped delay lines (TDL) with regularized and automated cell placements to generate a multitude of delayed signals with plenty of regularized phase shifts. Due to periodicity, those phase shifts will be equivalently wrapped within a reference clock period and then phase sorting, ROM-based selection are applied to construct a merged TDL with uniform phase division across the reference clock period. The FPGA TDC was implemented successfully on both Altera Stratix IV to achieve a resolution as fine as 1ps with a measurement range of 1s. The short-range integral non-linearity errors (INL) are measured as −1.470– 1.676 LSB for Stratix IV to demonstrate its excellent linearity.

In this paper, to advance acoustic waveguide transducers towards practical thermal ablation applications, we studied DPLUS (double parabolic reflectors wave-guided ultrasonic transducer) with a 1-m long (0.6-mm radius) and low-loss fused quartz thin waveguide working at the optimal frequency of 2.2 MHz, and the thermal effects to the tissue under different ultrasound exposure time. The measured vibration attenuation coefficient of the fused quartz thin waveguide is $\sim 0.0123$ dB/MHz/cm, and such low-loss characteristic is one of the keys of the studied DPLUS for realizing thermal ablation. Under the transmitted axial vibration velocity amplitude $v_{\mathrm {max}}$ at the thin waveguide tip of 1 m/s and the ultrasound exposure time of 1 s, 5 s, 10 s, 20 s, the measured temperature rises in the chicken breast tissue showed good agreements with the simulation results. Lesions were observed in the tissue under the exposure of 10 s, 20 s, and 30 s. The lesion size increases with the exposure time but the measured axial and lateral widths of the lesions were smaller than 2 mm. The presented results in this paper showed that thermal ablation was achieved by a m-range long thin-waveguide DPLUS which becomes an important progress of DPLUS towards practical MIT applications.

This study examined the use of avatars to provide feedback to influence action identities, anxiety, mood, and performance during job interview training. We recruited 36 university students for the experiment and divided them into two groups. The first group received avatar-based feedback whereas the other group received self-feedback after the first interview session. Results showed that the avatar-based feedback group experienced significantly higher levels of action identities, reduced anxiety, and happier mood in the second interview after the feedback session. Additionally, compared to the self-feedback group, the avatar-based feedback group rated their performance better in the second interview. Furthermore, the effect of avatar feedback on mood and performance varied depending on the participants’ initial anxiety levels. For those with low initial anxiety, avatar feedback resulted in higher levels of action identification, a marginally significant increase in positive mood, higher pitch, better word usage, and better self-assessment. In contrast, for those with high initial anxiety, avatar feedback did not cause any significant changes in the action identities or moods, however, it reduced anxiety and the use of weak words. We believe that our findings have implications not only for improving job interview performance but also for designing future communication coaching systems. [ABSTRACT FROM AUTHOR]

Building creativity in a remote group is challenging, and various methods to improve it have been investigated. However, the effect of a real-time feedback system on computer-mediated group creativity outcome remains undetermined. In this study, we studied the creativity performance of 20 two-person groups (dyads) while they engaged in a group alternative uses task via video-mediated communication and received real-time feedback cues based on turn-taking. The study included three conditions: turn-taking encouragement feedback (TTF), random time feedback (RF), and no feedback (NF). To probe the underlying mechanism, we assessed creativity outcomes, participants’ mood, and the temporal characteristics of the feedback effect type (i.e., slow gradual or instantaneous). The performance results revealed that TTF can enhance creativity outcome in the three dimensions of fluency, originality, and index of convergence. Comparing the self-reported moods indicated that the TTF cues heightened negative valence with high emotional arousal. While the results did not show any slow gradual changes in idea generation and idea quality differences between conditions, the results showed that the feedback cue impact was instantaneous. The results also indicated a significant instantaneous effect of immediate turn-taking on idea generation. Our findings suggest that the TTF condition enhanced cognitive persistence rather than cognitive flexibility during the remote group creativity session. The results of this study can be useful not only in remote human-to-human communications, but also in designing social robots and agents.