Improving policy understanding by means of secondary analyses of policy evaluation : a concept development

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A psychoacoustic "NofM"-type speech coding strategy for cochlear implants

We describe a new signal processing technique for cochlear implants using a psychoacoustic-masking model. The technique is based on the principle of a so-called "NofM" strategy. These strategies stimulate fewer channels (N) per cycle than active electrodes (NofM; N < M). In "NofM" strategies such as ACE or SPEAK, only the N channels with higher amplitudes are stimulated. The new strategy is based on the ACE strategy but uses a psychoacoustic-masking model in order to determine the essential components of any given audio signal. This new strategy was tested on device users in an acute Study, with either 4 or 8 channels stimulated per cycle. For the first condition (4 channels), the mean improvement over the ACE strategy was 17%. For the second condition (8 channels), no significant difference was found between the two strategies

trackswitch.js: A Versatile Web-Based Audio Player for Presenting Scientific Results

trackswitch.js is a versatile web-based audio player that enables researchers to conveniently present examples and results from scientific audio processing applications. Based on a multitrack architecture, trackswitch.js allows a listener to seamlessly switch between multiple audio tracks, while synchronously indicating the playback position within images associated to the audio tracks. These images may correspond to feature representations such as spectrograms or to visualizations of annotations such as structural boundaries or musical note information. The provided switching and playback functionalities are simple yet useful tools for analyzing, navigating, understanding, and evaluating results obtained from audio processing algorithms. Furthermore, trackswitch.js is an easily extendible and manageable software tool, designed for non-expert developers and unexperienced users. Offering a small but useful selection of options and buttons, trackswitch.js requires only basic knowledge to implement a versatile range of components for web-based audio demonstrators and user interfaces. Besides introducing the underlying techniques and the main functionalities of trackswitch.js we provide several use cases that indicate the flexibility and usability of our software for different audio- related research areas

Common Fate Model for Unison source Separation

International audienceIn this paper we present a novel source separation method aiming to overcome the difficulty of modelling non-stationary signals. The method can be applied to mixtures of musical instruments with frequency and/or amplitude modulation, e.g. typically caused by vi-brato. It is based on a signal representation that divides the complex spectrogram into a grid of patches of arbitrary size. These complex patches are then processed by a two-dimensional discrete Fourier transform, forming a tensor representation which reveals spectral and temporal modulation textures. Our representation can be seen as an alternative to modulation transforms computed on magnitude spectrograms. An adapted factorization model allows to decompose different time-varying harmonic sources based on their particular common modulation profile: hence the name Common Fate Model. The method is evaluated on musical instrument mixtures playing the same fundamental frequency (unison), showing improvement over other state-of-the-art methods

Durations required to distinguish noise and tone: Effects of noise bandwidth and frequency.

Perceptual audio coders exploit the masking properties of the human auditory system to reduce the bit rate in audio recording and transmission systems; it is intended that the quantization noise is just masked by the audio signal. The effectiveness of the audio signal as a masker depends on whether it is tone-like or noise-like. The determination of this, both physically and perceptually, depends on the duration of the stimuli. To gather information that might improve the efficiency of perceptual coders, the duration required to distinguish between a narrowband noise and a tone was measured as a function of center frequency and noise bandwidth. In experiment 1, duration thresholds were measured for isolated noise and tone bursts. In experiment 2, duration thresholds were measured for tone and noise segments embedded within longer tone pulses. In both experiments, center frequencies were 345, 754, 1456, and 2658 Hz and bandwidths were 0.25, 0.5, and 1 times the equivalent rectangular bandwidth of the auditory filter at each center frequency. The duration thresholds decreased with increasing bandwidth and with increasing center frequency up to 1456 Hz. It is argued that the duration thresholds depended mainly on the detection of amplitude fluctuations in the noise bursts.MRC (G0701870

Internationalization of Public Research Organizations. Context, Strategies and Effects

Atlanta Conference on Science and Innovation Policy 2009This presentation was part of the session : Globalization of Science and InnovationThis paper analyses (1) the context conditions of PRO and their roles in the (national) innovation systems, (2) the internationalisation strategies and (3) the effects of international activities on the performance and roles of PROs, whereby effects occur on the level of the organisations and on system's level. The paper thus contributes to the literature on the role of public research in the growing internationalisation of science and innovation. It also, more fundamentally, discusses the changes in the roles and functions of PROs more generally through internationalization. THe databasis is a large scale, comprehensive survey on German PROs and a set of case studies.Federal Ministry of Education and Research, German