Engineering Commons^™

Wavelet Based Islanding Detection Of Dc-Ac Inverter Interfaced Dg Systems, Mohamed Moin Hanif, Malabika Basu, Kevin Gaughan

Conference papers

The increased penetration of distributed generation (DG) often connected to grid through dc-ac interface has made islanding detection an important and challenging issue to power engineers. Several methods based on passive and active detection scheme have been proposed in the literature. While passive schemes have a large non detection zone (NDZ), concern has been raised on active method due to its degrading power quality effect. This paper proposes a wavelet based passive islanding detection scheme with almost zero NDZ for dc-ac inverter interfaced grid connected DGs. The key idea is to utilize the spectral changes in the higher frequency components …

Intelligibility Of Electrolarynx Speech Using A Novel Actuator, Brian Madden, Mark Nolan, Ted Burke, James Condron, Eugene Coyle

Conference Papers

During voiced speech, the larynx provides quasi-periodic acoustic excitation of the vocal tract. Following a laryngectomy, some people speak using an electrolarynx which replaces the excitatory function of the absent larynx. Drawbacks of conventional electrolarynx designs include the buzzing monotonic sound emitted, the need for a free hand to operate the device, and difficulty experienced by many laryngectomees in adapting to its use. Despite these shortcomings, it remains the preferred method of speech rehabilitation for a substantial minority of laryngectomees. In most electrolarynxes, mechanical vibrations are produced by a linear electromechanical actuator, the armature of which percusses against a metal …

Information Hiding Using Stochastic Diffusion For The Covert Transmission Of Encrypted Images, Jonathan Blackledge

Conference papers

A principal weakness of all encryption systems is that the output data can be `seen' to be encrypted. In other words, encrypted data provides a 'flag' on the potential value of the information that has been encrypted. In this paper, we provide a novel approach to `hiding' encrypted data in a digital image. We consider an approach in which a plaintext image is encrypted with a cipher using the processes of `stochastic diffusion' and the output quantized into a 1-bit array generating a binary image cipher-text. This output is then `embedded' in a host image which is undertaken either in …

Measuring Variations Of Mimicry By Means Of Prosodic Cues In Task-Based Scenarios And Conversational Speech, Brian Vaughan, Celine De Looze

Other resources

Here, we address the measurement of mimicry, that is when speakers’ speech variations look like parallel patterns.

As a definition of mimicry, we often read in the literature description such as mimicry is “The situation where the observed behaviours of two inter-actants although dissimilar at the start of the interaction are moving towards behavioral matching”. These types of descriptions imply that mimicry is a linear phenomenon and that speakers tend to imitate over time. However, it can be assumed, especially when studying spontaneous speech, that there are rather phases of mimicry and non-mimicry and that mimicry should be rather …

Single Channel Vocal Separation Using Median Filtering And Factorisation Techniques, Derry Fitzgerald, Mikel Gainza

Articles

This paper deals with the problem of the extraction of vocals from single channel audio signals containing both vocals and other instruments, including both pitched instruments and percussion instruments. A novel median filtering-based approach for the extraction of vocal tracks is described, which is simple and efficient to implement. Further improvements in separation quality are then obtained by the application of tensor factorisation techniques to further extract residual instruments from the vocal mix. Finally, a novel use of non-negative partial matrix cofactorisation is demonstrated as a means of further improving separation quality. Here the original single channel mixture is partially …

Locating Tune Changes And Providing A Semantic Labelling Of Sets Of Irish Traditional Tunes, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle

Conference papers

An approach is presented which provides the tune change loactions within a set of Irish traditional turnes. Also provided are semantic labels for each part of each tune within the set. A set in Irish traditional music is a number of individual tunes played segue. Each of the tunes in the set are made up of structural segments called parts. Musical variation is a prominent characteristic of this genre. However, a certain set of notes known as "set accented tones" are considered impervious to musical variation. Chroma information is extracted at "set accented tone" locations within the music. The resulting …

Exploiting Glottal Formant Parameters For Glottal Inverse Filtering And Parameterization, Alan O'Cinneide, David Dorran, Mikel Gainza, Eugene Coyle

Conference papers

It is crucial for many methods of inverse filtering that the time domain information of the glottal source waveform is known, e.g. the location of the instant of glottal closure. It is often the case that this information is unknown and/or cannot be determined due to e.g. recording conditions which can corrupt the phase spectrum. In these scenarios, alternative strategies are required. This paper describes a method which, given the parameters of the glottal formant of the signal frame, can accurately parameterize the glottal shape source and vocal filter for a broad range of voice quality types and which is …

Harmonic/Percussive Separation Using Median Filtering, Derry Fitzgerald

Conference papers

In this paper, we present a fast, simple and effective method to separate the harmonic and percussive parts of a monaural audio signal.The technique involves the use of median filtering on a spectrogram of the audio signal, with median filtering performed across successive frames to suppress percussive events and enhance harmonic components, while median filtering is also performed across frequency bins to enhance percussive events and supress harmonic components. The two resulting median filtered spectrograms are then used to generate masks which are then applied to the original spectrogram to separate the harmonic and percussive parts of the signal. We …

Interactive Music Archive Access System, Martin Gallagher, Derry Fitzgerald, Dan Barry, Matt Cranitch, Eugene Coyle

Conference papers

The goal of the Interactive Music Archive Access System (IMAAS) project was to develop an interactive music archive access system which was capable of allowing an end-user to easily extract rhythmic, melodic and harmonic musical metadata descriptors from audio, and allow the user to interact with the archive contents in a manner not typically allowed in archive access systems. To this end, the IMAAS system incorporates a range of real-time interaction tools which allow the user to modify the retrieved audio in a number of ways including the ability to isolate individual instruments in stereo mixes, pitch and time-scale modification, …

Audio Thumbnail Generation Of Irish Traditional Music, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle

Conference papers

An approach is presented which generates an audio thumbnail of Irish traditional music. An audio thumbnail is consered to be the most representative segment of the music. For popular music, the chorus is considered to be an ideal audio thumbnail, however in Irish Traditional Music there is no chorus. An Irish Traditional tune consists of tow or mor short structural segments called parts. Parts are repeated to extend the tuen, and the tune itself is also repeated once or more in its entirety. To further extend a performance, tunes are concatenated to form a set of tuens. As a result, …

On The Use Of A Dynamic Hybrid Tempo Detection Model For Beat Tracking, Mikel Gainza

Conference papers

In this paper, an approach that estimates the times at which musical beats occur is presented. The system uses a hybrid multi-band decomposition in order to estimate the music tempo. Following this, beat events are tracked by using a dynamic programming approach, which is updated by using short time tempo estimates. The hybrid decomposition is used in order to calculate the tempo by using different onset detection functions in different frequency bands. In addition, a method that estimates which frequency bands provide reliable periodicities is also presented. The accuracy of the model is evaluated by comparing the presented system against …

On The Appearance Of A Positive Real Pole In The Results Of Glottal Closed Phase Linear Prediction, Alan O'Cinneide, David Dorran, Mikel Gainza, Eugene Coyle

Conference papers

Often when performing glottal closed phase covariance linear prediction, a positive real pole can appear in the resulting filter transfer function. The commonly adopted approach is to discard this pole, as it does not fit with the usual model of the all-pole vocal tract filter. However, this real pole describes some aspect of the speech signal; this paper provides a novel perspective on its occurrence. This viewpoint has a useful implication to the speech community, especially from the perspective of fitting a glottal pulse to the inverse filtered signal, as the real pole describes the return phase of the glottal …

Towards A Method To Determine The Glottal Formant Parameters Of Voiced Speech Without Time-Domain Reference, Alan O'Cinneide, David Dorran, Mikel Gainza, Eugene Coyle

Conference papers

This paper presents an approach to estimate the glottal formant parameters of the voicing source in the frequency-domain. The method is based on a simplified pole-zero interpretion of the prevalent Liljencrants-Fant (LF) model of glottal flow, and gives approximations for a broad range of pulses shapes. An advantage of the method is that, unlike other methods, it does not rely on time-domain references.