多带抗噪声语音识别算法研究

根据Flether等人的研究,基于感知独立性假设的子带识别方法被用于抗噪声鲁棒语音识别。本文拓展子带方法,采用基于噪声污染假定的多带框架来减少噪声影响。论文不仅从理论上分析了噪声污染假定多带框架在识别性能上的潜在优势,而且提出了多带环境下的鲁棒语音识别算法。研究表明：多带框架不仅回避了独立感知假设要求,而且与子带方法相比,多带方法能更好的减少噪声影响,提高系统识别性能。     

STUDY ON PHASE PERCEPTION IN SPEECH

The perceptual effect of the phase information in speech has been studied by auditory subjective tests. On the condition that the phase spectrum in speech is changed while amplitude spectrum is unchanged, the tests show that: (1) If the envelop of the reconstructed speech signal is unchanged, there is indistinctive auditory perception between the original speech and the reconstructed speech; (2) The auditory perception effect of the reconstructed speech mainly lies on the amplitude of the derivative of the additive phase; (3) td is the maximum relative time shift between different frequency components of the reconstructed speech signal. The speech quality is excellent while td <10ms; good while 10ms< td <20ms; common while 20ms< td <35ms, and poor while td >35ms.     

Gaze cueing of attention: Visual attention, social cognition, and individual differences.

During social interactions, people's eyes convey a wealth of information about their direction of attention and their emotional and mental states. This review aims to provide a comprehensive overview of past and current research into the perception of gaze behavior and its effect on the observer. This encompasses the perception of gaze direction and its influence on perception of the other person, as well as gaze-following behavior such as joint attention, in infant, adult, and clinical populations. Particular focus is given to the gaze-cueing paradigm that has been used to investigate the mechanisms of joint attention. The contribution of this paradigm has been significant and will likely continue to advance knowledge across diverse fields within psychology and neuroscience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

无源传感器对雷达目标指示中触发准则研究

针对多传感器协同跟踪中无源传感器对雷达的目标指示问题进行了深入分析,重点研究了目标的指示交接需求及其触发机制.分析了协同跟踪中的目标指示交接需求,同时依据无源与有源传感器协同特性建立顺序处理结构的多传感器融合跟踪模型.在此基础上,采用协方差控制思想设定无源传感器对雷达的目标指示触发准则.通过仿真对触发准则进行了验证,并讨论了目标指示触发时机的影响因素,确保传感器间的目标指示能够自发进行.     

Enhanced auditory feedback for Korean touch screen keyboards

With the increasing popularity of touch screen mobile devices, improving the usability and the user experience while inputting text on these devices is becoming increasingly important. Most conventional touch screen keyboards on mobile devices rely heavily on visual feedback, while auditory feedback seldom includes any useful information about what is being inputted by the user. The auditory feedback usually simply replicates the sounds produced by a physical keyboard. This paper describes the development of an enhanced auditory feedback mechanism for a Korean touch screen keyboard called the enhanced auditory feedback (EAF) mechanism. EAF has subtle phonetic auditory feedback generated using the acoustic phonetic features of human speech. While typing with EAF, users can acquire non-invasive auditory clues about the keys pressed. In this work, we compare conventional auditory feedback for a touch screen keyboard used in touch screen mobile devices with that of EAF and explore the possibility of using enhanced auditory feedback for touch screen keyboards.     

Tuning the Sonic Playing Field: Teaching Ways of Knowing Sound in First Year Writing

In recent years there has been a call within composition to include sound, among other modes, such as word and image in writing. Some of this call relies on a movement to multimodal composition in order to capture both the richness of rhetorical possibility and the reality of communities of practice, and some is in response to a perceived shift in writing due to digital media tools and environments. Regardless of the impetus for including the auditory realm in the composition classroom, it is important for the field of composition and rhetoric to develop further pedagogies of sound so that students are not simply offered the opportunity to produce diverse texts, but instead, are invited to enter “the playing field.” In order to do this I first explore an approach to teaching auditory rhetoric based on ways of knowing sound from an acoustics and musicology perspective, then I consider a phenomenological approach based on listening, and finally I construct a model of “tuning the sonic playing field” that draws on the literal, material practice of tuning as a metaphor for how sound may be taught in composition. The “tuning” approach to teaching sound draws on attention, embodiment, listening, and negotiation. Rather than simply offering students opportunities to use sound in rhetorically sensitive ways, this final approach asks instructors to become “attuned” to how different auditory epistemologies influence students’ ability to design and compose in sound.     

Direction coding using a tactile chair

This laboratory study examined the possibility of using a car seat instrumented with a tactile display to communicate directional information to a driver. A car seat fitted with an 8 × 8 matrix of vibrators embedded in the seat pan was used to code eight different directions. Localization response time and angular accuracy were examined as a function of stimulus direction, presence of a tactile attention cue, temporal pattern, stimulus layout, age, and gender. The mean absolute angular error was 23°, and both localization accuracy and response times were superior for the back left, backward, and back right directions. Of the various temporal pattern/attention cue combinations examined, results favored the relatively fast patterns consisting of vibration bursts of 125 or 250 ms without a centrally located attention cue over 500 ms bursts that were preceded by an attention cue. Observed age and gender effects were relatively modest, suggesting that using tactile cueing to communicate direction is effective across a wide range of users. In addition, the tactile stimulus was detected by more than 90% of the participants under surprise trial conditions. Overall, these results indicate that the tactile chair provides a promising and robust method of providing directional information.     

Design of an auditory guidance system for the blind with signal transformation from stereo ultrasonic to binaural audio

We have designed an auditory guidance system for the blind using ultrasonic-to-audio signal transformation. We first investigated the system requirements, and designed a simple but useful portable guidance system for the blind. The system derives visual information using multiple ultrasonic sensors, and transforms it to binaural auditory information using a suitable technique. The user can recognize the position of obstacles and the surrounding environment. The system is composed of two parts. One is a glasses-type system, and the other is a cane-type system with guide wheels. The former functions as an environment sensor, and the latter functions as a clear-path indicator. Wide-beam-angle ultrasonic sensors are used to detect bojects over a broader range. The system is designed as a battery-supplied portable model. Our design is focused on low power consumption, small size, light weight, and easy manipulation.     

Multimodal feedback: an assessment of performance and mental workload

Multimodal interfaces offer great potential to humanize interactions with computers by employing a multitude of perceptual channels. This paper reports on a novel multimodal interface using auditory, haptic and visual feedback in a direct manipulation task to establish new recommendations for multimodal feedback, in particular uni-, bi- and trimodal feedback. A close examination of combinations of uni-, bi- and trimodal feedback is necessary to determine which enhances performance without increasing workload. Thirty-two participants were asked to complete a task consisting of a series of ‘drag-and-drops’ while the type of feedback was manipulated. Each participant was exposed to three unimodal feedback conditions, three bimodal feedback conditions and one trimodal feedback condition that used auditory, visual and haptic feedback alone, and in combination. Performance under the different conditions was assessed with measures of trial completion time, target highlight time and a self-reported workload assessment captured by the NASA Task Load Index (NASA-TLX). The findings suggest that certain types of bimodal feedback can enhance performance while lowering self-perceived mental demand.     

Evaluation of acoustic beacon characteristics for navigation tasks

The goal of the present study was to investigate the human factors issues related to acoustic beacons used for auditory navigation. Specific issues addressed were: (1) the effect of various beacon characteristics on human accuracy in turning toward the direction of the acoustic beacon; (2) the difference between real and virtual environments on human accuracy in turning toward the acoustic beacon; and (3) the perceived sound quality of various acoustic beacons. Three experiments were conducted in which acoustic beacons were presented in a background of 80 dBA pink noise. Results of the localization tasks revealed that (a) presentation mode (continuous versus pulsed beacon sound) did not affect the overall localization accuracy or number of front-back confusion errors; and (b) the type of acoustic beacon affected the size of localization error. Results of the sound quality assessment indicated that listeners had definite preferences regarding the type of sound being used as a beacon, with (a) non-speech beacons preferred over speech beacons, (b) a beacon repetition rate of 1.1 rps preferred over either the 0.7 or 2.5 rps rates, and (c) a continuous operation of a beacon preferred over a pulsed operation. Finally, sound quality ratings and localization errors were highly negatively correlated. This finding demonstrates the usefulness and practical values of sound quality judgements for audio display design and evaluation.