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- Fast Handoff (2)
- Fractional Diffusion (2)
- Image Processing (2)
- Non-negative Tensor Factorisation (2)
- Sound Source Separation (2)
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- Wireless Mesh Network (2)
- Access Efficiency Factor (1)
- Active Handoff (1)
- Beta Divergence (1)
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- DFIG (1)
- DSR Routing Protocol (1)
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- Diagnostic test results (1)
- Drum Sound Separation (1)
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- Electrical systems (1)
- First year engineering students (1)
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- IEEE 802.11 (1)
- Information Hiding (1)
- Information hiding (1)
- Inverse Scattering (1)
- Language (1)
- Localization Quality Assessment in Source Separation-Based Upmixing Algorithms (1)
- Markov Chain (1)
- Meter (1)
- Micro Generation (1)
- Multi-radio (1)
- Multiple Scattering (1)
Articles 1 - 19 of 19
Full-Text Articles in Engineering
Meshscan: Performance Of Passive Handoff And Active Handoff, Yin Chen, Karol Kowalik, Mark Davis
Meshscan: Performance Of Passive Handoff And Active Handoff, Yin Chen, Karol Kowalik, Mark Davis
Conference papers
A core problem of fast handoff is when handoff should perform and which Mesh Node (MN) should associated with. We have developed a fast handoff management scheme called MeshScan to provide a novel use of channel scanning latency, by employing open system authentication in both Passive Handoff and Active Handoff. This scheme comprises three steps: firstly a client device takes advantage of the Wireless Mesh Network (WMN) architecture to maintain a list of active MNs. Secondly MeshScan Handoff Sensor performs handoff when it receives a disassociation management frame from the serving MN or when the measured signal strength from the …
Meshscan: Fast And Efficient Handoff In Ieee802.11 Mesh Networks, Yin Chen, Mark Davis
Meshscan: Fast And Efficient Handoff In Ieee802.11 Mesh Networks, Yin Chen, Mark Davis
Conference papers
Handoff delay is one of the major problems in Wireless Mesh Network (WMN) that needs to be solved in order to allow time-critical and real-time applications run continuously during handoff. We have developed a fast handoff scheme called MeshScan to provide a novel use of channel scanning latency by employing open system authentication. This scheme comprises two steps: firstly a client device takes advantage of the WMN architecture to maintain a list of active mesh nodes. Secondly when handoff is required, a client transmits Authentication Request frames to all mesh nodes (MNs) from the list instead of broadcasting Probe Request …
The Integrated Control Of The Rotor Side And Grid Side Converters In A Dfig To Reduce Both Power And Torque Pulsations During Network Voltage Unbalance Conditions., Joseph Kearney, Michael Conlon, Eugene Coyle
The Integrated Control Of The Rotor Side And Grid Side Converters In A Dfig To Reduce Both Power And Torque Pulsations During Network Voltage Unbalance Conditions., Joseph Kearney, Michael Conlon, Eugene Coyle
Conference papers
No abstract provided.
An Experimental Study Of The Impact Of Using Multi-Radio In Wlan Mesh Networks, Chenzhe Zhang, Karol Kowalik, Mark Davis
An Experimental Study Of The Impact Of Using Multi-Radio In Wlan Mesh Networks, Chenzhe Zhang, Karol Kowalik, Mark Davis
Conference papers
Next-generation wireless mobile communications will be driven by converged networks that integrate disparate technologies and services. Wireless Mesh Networks (WMNs) are expected to be one of the next generation of wireless interconnection technologies, providing flexible high bandwidth wireless backhaul over large geographical areas. While single radio mesh nodes operating on a single channel suffer from capacity constraints, equipping mesh routers with multiple radios using multiple non-overlapping channels can significantly alleviate the capacity problem and increase the aggregate bandwidth available to the network. However, it is well known that multi-radio Mesh platforms face many limitations such as interference, radiation leakage, crosstalk …
Information Hiding By Stochastic Diffusion And Its Application To Printed Document Authentication, Jonathan Blackledge, Eugene Coyle
Information Hiding By Stochastic Diffusion And Its Application To Printed Document Authentication, Jonathan Blackledge, Eugene Coyle
Conference papers
The use of image based information exchange has grown rapidly over the years in terms of both e-to-e image storage and transmission and in terms of maintaining paper documents in electronic form. Further, with the dramatic improvements in the quality of COTS (Commercial-Off-The-Shelf) printing and scanning devices, the ability to counterfeit electronic and printed documents has become a widespread problem. Consequently, there has been an increasing demand to develop digital watermarking, information hiding and covert encryption methods which can be applied to both electronic and printed images (and documents) for the purposes of authentication, prevent unauthorized copying and, in the …
Performance Study Of A Cross-Layer Optimization To The Dsr Routing Protocol In Wireless Mesh Networks, Mustafa Ramadhan, Mark Davis
Performance Study Of A Cross-Layer Optimization To The Dsr Routing Protocol In Wireless Mesh Networks, Mustafa Ramadhan, Mark Davis
Conference papers
A cross-layer modification to the DSR protocol is presented in this work which is intended to enhance the global throughput performance of wireless mesh networks. This modification involves the use of an access efficiency factor (which is a measure of the local availability of bandwidth at a node) as an alternative metric to the hop-count metric in order to allow for improved routing selection. The key feature of this modified route selection procedure is that it attempts to discover paths that have a large availability of bandwidth which can support high throughputs. In this work we have employed the OPNET …
Diffusion And Fractional Diffusion Based Image Processing, Jonathan Blackledge
Diffusion And Fractional Diffusion Based Image Processing, Jonathan Blackledge
Conference papers
We consider the background to describing strong scattering in terms of diffusive processes based on the diffusion equation. Intermediate strength scattering is then considered in terms of a fractional diffusion equation which is studied using results from fractional calculus. This approach is justified in terms of the generalization of a random walk model with no statistical bias in the phase to a random walk that has a phase bias and is thus, only ‘partially’ or ‘fractionally’ diffusive. A Green’s function solution to the fractional diffusion equation is studied and a result derived that provides a model for an incoherent image …
Inverse Scattering Solutions For Side-Band Signals, Jonathan Blackledge, Timo Hamalainen, Jyrki Joutsensalo
Inverse Scattering Solutions For Side-Band Signals, Jonathan Blackledge, Timo Hamalainen, Jyrki Joutsensalo
Conference papers
When a signal is recorded that has been physically generated by some scattering process (the interaction of electromagnetic waves with an inhomogeneous dielectric, for example), the `standard model' for the signal (i.e. information content convolved with a characteristic Impulse Response Function) is usually based on a single scattering approximation. An additive noise term is introduced into the model to take into account a range of non-deterministic factors including multiple scattering that, along with electronic noise and other background noise sources, is assumed to be relatively weak. Thus, the standard model is based on a `weak field condition' and the inverse …
The Probabilistic Integration Of Demand-Side Load And Generation In A Representative Irish Distribution Network, Keith Sunderland, Michael Conlon
The Probabilistic Integration Of Demand-Side Load And Generation In A Representative Irish Distribution Network, Keith Sunderland, Michael Conlon
Conference papers
This paper introduces a methodology for investigating the behaviour of a distribution network incorporating both load variations and variable micro-wind generation output. The probabilistic methodology is applied to a representative model of the Irish Distribution Network. Application of a selection of commercially available micro-wind turbines to the model is investigated for a range of load and generation scenarios based on a standard load profile and varying mean wind speed. Analysis of the results of the analysis forms the basis for defining the limitations of the methodology but also presents the opportunities for future work.
Localization Quality Assessment In Source Separation-Based Upmixing Algorithms, Dan Barry, Gavin Kearney
Localization Quality Assessment In Source Separation-Based Upmixing Algorithms, Dan Barry, Gavin Kearney
Conference papers
In this paper we explore the source localisation accuracy and perceived spatial distortion of a source separation based upmix algorithm for 2 to 5 channel conversion. Unlike traditional upmixing techniques, source separation based techniques allow individual sources to be separated from the mixture and repositioned independently within the surround sound field. Generally, spectral artefacts and source interference generated during the source separation process are masked when the upmixed sound field is presented in its entirety; however, this can lead to perceived spatial distortion and ambiguous source localisation. Here, we use subjective testing to compare the localisation perceived on a purposely …
Automatic Musical Meter Detection, Mikel Gainza
Automatic Musical Meter Detection, Mikel Gainza
Conference papers
A method that automatically estimates the metrical structure of a piece of music is presented. The approach is based on the generation of a beat similarity matrix, which provided information about the similarity between any two beats of a piece of music. The repetitive structure of most music is exploited by processing the beat similarity matrix in order to identify similar patterns of beats in different parts of a piece. This principles proves to be equally effective for the detection of both duple and triple meters as awll as complex meters. The use of beat positions and dynamic programming techniques …
Structural Segmentation Of Irish Traditional Music Using Chroma At Set Accented Tone Locations, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle
Structural Segmentation Of Irish Traditional Music Using Chroma At Set Accented Tone Locations, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle
Conference papers
An approach is presented which provides a structural segmentation of Irish Traditional Music. Chroma information is extracted at certain locations within the music. The resulting chroma vectors are compared to determine similar structural segments. Chroma is only calculated at "set accented tone" locatins within the music. "Set accented tones" are considered to be impervious to melodic variation and are entirely representative of an Irish Traditional tune. Results show that comparing "set accented tones" represented by chroma significantly increases the structural segmentation accuracy that when "set accented tones" are represented by pitch values.
Using Tensor Factorisation Models To Separate Drums From Polyphonic Music, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Using Tensor Factorisation Models To Separate Drums From Polyphonic Music, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Conference papers
This paper describes the use of Non-negative Tensor Factorisation models for the separation of drums from polyphonic audio. Improved separation of the drums is achieved through the incorporation of Gamma Chain priors into the Non-negative Tensor Factorisation framework. In contrast to many previous approaches, the method used in this paper requires little or no pre-training or use of drum templates. The utility of the technique is shown on real-world audio examples.
Musical Sound Source Separation Using Extended Tensor Decompositions, Derry Fitzgerald
Musical Sound Source Separation Using Extended Tensor Decompositions, Derry Fitzgerald
Conference papers
Recently, tensor decompositions have found use in sound source separation. In particular, non-negative tensor decompositions have received a lot of attention due to their ability to decompose audio spectrograms into meaningful ”parts” such as individual notes. Extensions to the basic non-negative tensor factorisation framework allow the incorporation of additional constraints, such as shift-invariance in both frequency and time. This enables the factorisations to capture more complex structures than individual notes, such as individual sources playing different pitches and time-evolving instrument timbres. Further music specific constraints such as harmonicity and source-filter modeling have been shown to improve separation performance for musical …
Imaging Reconstruction For Light Scattering From A Tenuous Random Medium, Jonathan Blackledge
Imaging Reconstruction For Light Scattering From A Tenuous Random Medium, Jonathan Blackledge
Conference papers
We consider the basis for describing strong scattering in terms of diffusive processes based on the diffusion equation. Intermediate strength scattering is then considered in terms of a fractional diffusion equation which is studied using results from fractional calculus. This approach is justified in terms of the generalization of a random walk model with no statistical bias in the phase to a random walk that has a phase bias and is thus, only `partially' or `fractionally' diffusive. A Green's function solution to the fractional diffusion equation is studied and a result derived that provides a model for an incoherent image …
Prior Understanding Of Basic Electrical Circuit Concepts By First Year Engineering Students, Aidan O'Dwyer
Prior Understanding Of Basic Electrical Circuit Concepts By First Year Engineering Students, Aidan O'Dwyer
Conference papers
There is a broad diversity of educational background of students entering Level 7 programmes in engineering. As a result, students’ reasoning regarding basic electrical concepts often differs from accepted explanations. This contribution reports, analyses and reflects on the results of a multiple-choice diagnostic test to assess student understanding of such concepts (developed by Engelhardt and Beichner (2004) for high school and college students), taken by three cohorts of first year, Level 7, engineering students at Dublin Institute of Technology during the 2008-9 academic year.
Generating Natural Language Descriptions Of Ontology Concepts, Niels Schütte
Generating Natural Language Descriptions Of Ontology Concepts, Niels Schütte
Conference papers
This paper gives an overview of ongoing work on a system for the generation of NL descriptions of classes defined in OWL ontologies. We present a general structuring approach for such descriptions. Since OWL ontologies do not by default contain the information necessary for lexicalization, lexical information has to be added to the data via annotations. A rulebased mechanism for automatically deriving these annotations is presented.
On The Use Of The Beta Divergence For Musical Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
On The Use Of The Beta Divergence For Musical Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Conference papers
Non-negative Tensor Factorisation based methods have found use in the context of musical sound source separation. These techniques require the use of a suitable cost function to determine the optimal factorisation, and most work has focused on the use of the generalised Kullback-Liebler divergence, and more recently the Itakura-Saito divergence. These divergences can be regarded as limiting cases of the parameterised Beta divergence. This paper looks at the use of the Beta Divergence in the context of musical source separation with a view to determining an optimal value of Beta for this problem. This is considered for both magnitude and …
Information Hiding By Stochastic Disfusion And Its Application To Printed Document Authentication, Jonathan Blackledge, Eugene Coyle
Information Hiding By Stochastic Disfusion And Its Application To Printed Document Authentication, Jonathan Blackledge, Eugene Coyle
Conference papers
The use of image based information exchange has grown rapidly over the years in terms of both e-to-e image storage and transmission and in terms of maintaining paper documents in electronic form. Further, with the dramatic improvements in the quality of COTS (Commercial-O-The-Shelf) printing and scanning devices, the ability to counterfeit electronic and printed documents has become a widespread problem. Consequently, there has been an increasing demand to develop digital watermarking, information hiding and covert encryption methods which can be applied to both electronic and printed images (and documents) for the purposes of authentication, prevent unauthorized copying and, in the …