Silent-speech enhancement using body-conducted vocal-tract resonance signals

The physical characteristics of weak body-conducted vocal-tract resonance signals called non-audible murmur (NAM) and the acoustic characteristics of three sensors developed for detecting these signals have been investigated. NAM signals attenuate 50 dB at 1 kHz; this attenuation consists of 30-dB full-range attenuation due to air-to-body transmission loss and 10 dB/octave spectral decay due to a sound propagation loss within the body. These characteristics agree with the spectral characteristics of measured NAM signals. The sensors have a sensitivity of between 41 and 58 dB [V/Pa] at I kHz, and the mean signal-to-noise ratio of the detected signals was 15 dB. On the basis of these investigations, three types of silent-speech enhancement systems were developed: (1) simple, direct amplification of weak vocal-tract resonance signals using a wired urethane-elastomer NAM microphone, (2) simple, direct amplification using a wireless urethane-elastomer-duplex NAM microphone, and (3) transformation of the weak vocal-tract resonance signals sensed by a soft-silicone NAM microphone into whispered speech using statistical conversion. Field testing of the systems showed that they enable voice impaired people to communicate verbally using body-conducted vocal-tract resonance signals. Listening tests demonstrated that weak body-conducted vocal-tract resonance sounds can be transformed into intelligible whispered speech sounds. Using these systems, people with voice impairments can re-acquire speech communication with less effort. (C) 2009 Elsevier B.V. All rights reserved.ArticleSPEECH COMMUNICATION. 52(4):301-313 (2010)journal articl

脳卒中片麻痺患者の立位姿勢制御における周辺視野の影響

脳卒中片麻痺患者(以下、Stroke患者)を対象として、視野内への平行棒提示の有無によって重心動揺および重心移動域が変化するかを実験的に検討した。回復期病棟へ入院中のStroke患者7名を対象とした。重心動揺計を用いて、頭頚部屈曲位で下方を注視する条件(下方条件)、下方条件と同一肢位で視野内に平行棒を提示する条件、の2条件における総軌跡長、実効値面積、前後左右への重心移動面積(安定域面積)を計測し、比較した。静的時の重心動揺の指標である総軌跡長および実効値面積については2条件間に有意差は認めなかった(両指標ともp>0.05)。動的な重心動揺の指標である安定域面積は、下方条件と比較して平行棒条件で有意な増大がみられた(p=0.016)。下方を向いた条件下での視覚参照枠は、静止時の重心動揺には影響を与えず、能動的な重心移動を改善させることが示された。Stroke patients often claimed the fear of falling when upright standing in the large space without support rather than in the narrow space with supporting objects,even they did not touch the objects as a support. We investigated the effects of the parallel bars as a cognitive support. Seven stroke patients who admitted to the hospital were participated. The length of total center of pressure(LNG),the root mean square of sway area(RMS area) and the voluntary maximum sway area(Max area) were measured under the following 2 conditions: eyes fixed downward(downward condition), eyes fixed downward with the parallel bars presented in the peripheral visual field(bar condition). The results showed that the no difference had observed between conditions in the LNG and RMS area (p>0.05). The bar condition increased the Max area when compared with downward condition(p=0.016). Our results showed that the peripherally visual objects(cognitive support) improved the voluntary movement of center of pressure, and we speculated that the motion parallax contributed to the mechanism of this result

Effect of Eye-Object Distance on Body Sway during Galvanic Vestibular Stimulation

Gazing at objects at a near distance (small eye-object distance) can reduce body sway. However, whether body sway is regulated by movement in the mediolateral or anteroposterior direction remains unclear. Galvanic vestibular stimulation (GVS) can induce body tilting in the mediolateral or anteroposterior direction. This study examined the directionality of the eye-object distance effect, using body-tilting GVS manipulations. Ten healthy subjects (aged 21.1 ± 0.3 years) stood on a force plate covered with a piece of foamed rubber and either closed their eyes or gazed at a marker located 0.5 m, 1.0 m, or 1.5 m in front of them. The GVS polarities were set to evoke rightward, forward, and backward body tilts. To compare the effects of eye-object distance in the mediolateral and anteroposterior directions, the root mean square (RMS) of the center of pressure (COP) without GVS was subtracted from the COP RMS during GVS. For swaying in the mediolateral direction, significant visual condition-related differences were found during rightward and forward GVS (p < 0.05). Thus, reductions in mediolateral body sway are more evident for smaller eye-object distances during rightward GVS. It would be appropriate to use body-tilting GVS to detect the directionality of the eye-object distance effect

A -31.7 dBm Sensitivity 0.011 mm2 CMOS On-Chip Rectifier for Microwave Wireless Power Transfer

publishe

Action-rule-based cognitive control enables efficient execution of stimulus–response conflict tasks: a model validation of Simon task performance

Introduction: The human brain can flexibly modify behavioral rules to optimize task performance (speed and accuracy) by minimizing cognitive load. To show this flexibility, we propose an action-rule-based cognitive control (ARC) model. The ARC model was based on a stochastic framework consistent with an active inference of the free energy principle, combined with schematic brain network systems regulated by the dorsal anterior cingulate cortex (dACC), to develop several hypotheses for demonstrating the validity of the ARC model. Methods: A step-motion Simon task was developed involving congruence or incongruence between important symbolic information (illustration of a foot labeled “L” or “R,” where “L” requests left and “R” requests right foot movement) and irrelevant spatial information (whether the illustration is actually of a left or right foot). We made predictions for behavioral and brain responses to testify to the theoretical predictions. Results: Task responses combined with event-related deep-brain activity (ER-DBA) measures demonstrated a key contribution of the dACC in this process and provided evidence for the main prediction that the dACC could reduce the Shannon surprise term in the free energy formula by internally reversing the irrelevant rapid anticipatory postural adaptation. We also found sequential effects with modulated dip depths of ER-DBA waveforms that support the prediction that repeated stimuli with the same congruency can promote remodeling of the internal model through the information gain term while counterbalancing the surprise term. Discussion: Overall, our results were consistent with experimental predictions, which may support the validity of the ARC model. The sequential effect accompanied by dip modulation of ER-DBA waveforms suggests that cognitive cost is saved while maintaining cognitive performance in accordance with the framework of the ARC based on 1-bit congruency-dependent selective control