A Computational Model of Auditory Feature Extraction and Sound Classification

This thesis introduces a computer model that incorporates responses similar to those found in the cochlea, in sub-corticai auditory processing, and in auditory cortex. The principle aim of this work is to show that this can form the basis for a biologically plausible mechanism of auditory stimulus classification. We will show that this classification is robust to stimulus variation and time compression. In addition, the response of the system is shown to support multiple, concurrent, behaviourally relevant classifications of natural stimuli (speech). The model incorporates transient enhancement, an ensemble of spectro - temporal filters, and a simple measure analogous to the idea of visual salience to produce a quasi-static description of the stimulus suitable either for classification with an analogue artificial neural network or, using appropriate rate coding, a classifier based on artificial spiking neurons. We also show that the spectotemporal ensemble can be derived from a limited class of 'formative' stimuli, consistent with a developmental interpretation of ensemble formation. In addition, ensembles chosen on information theoretic grounds consist of filters with relatively simple geometries, which is consistent with reports of responses in mammalian thalamus and auditory cortex. A powerful feature of this approach is that the ensemble response, from which salient auditory events are identified, amounts to stimulus-ensemble driven method of segmentation which respects the envelope of the stimulus, and leads to a quasi-static representation of auditory events which is suitable for spike rate coding. We also present evidence that the encoded auditory events may form the basis of a representation-of-similarity, or second order isomorphism, which implies a representational space that respects similarity relationships between stimuli including novel stimuli

SUSTAINABLE AGRIBUSINESS: DEVELOPING LOCAL SOLUTIONS TO GLOBAL CHALLENGES IN THE REGIONAL AGRIBUSINESS SECTOR IN AUSTRALIA

The competitiveness of the agribusiness sector is critical to the social and economic sustainability of regional Australia, where agribusiness is directly responsible for one in five jobs (DNRE, 2002). Although it is recognised that environmental issues must be considered in order to 'sustain' the natural resources used to produce food, this paper focuses on the social and economic issues relating to sustainability (Cocklin et at., 2001). Social sustainability has only recently been upheld as an aim of agricultural and regional policy in Australia, however, it has typically been considered less important than economic and ecological sustainability (Cocklin et al., 2001). In rural Australia, social sustainability is typically reflected in the maintenance of social networks among residents of a rural area, the viability of the rural towns and the associated provision of infrastructure, facilities and services. The State Government of Victoria is actively encouraging the development and maintenance of sustainable networks of agribusiness-related entities in regional and rural Victoria. The Victoria Agribusiness Networks program is an example of how government is engaging agribusiness communities in regional Victoria.Agribusiness,

An Approach to Increasing Participation in the Community Health Assessment in Northampton County, North Carolina

The mission of Northampton County Health Department, located in Jackson, NC, is to promote, provide, and protect the health and safety of the citizens of the County (NCHD, 2018). One of the responsibilities of the health department is to conduct the community health assessment (CHA) every four years to provide a summary of the health conditions in the community and foster increased collaboration among stakeholders. While community engagement in the CHA is crucial to improve the health in the community, inclusivity and participation in the process is not always optimal. The reasons may be lack of community awareness about the importance of the CHA as well as barriers that inhibit engagement. This paper describes a proposed program plan utilizing the Community Organization and Other Participatory Models theoretical framework to increase inclusivity and participation in the CHA in Northampton County, NC. The health department will lead the campaign over a 4-year period by training health department staff and community coalition volunteers to organize a CHA advocacy team, implement the CHA, and perform a CHA follow up. This CHA advocacy team will implement the proposed program plan through social marketing techniques by using local media, 40 local faith leaders or their assistants, and lay volunteers who will be trained as community champions. They will engage the community by continuing to spread awareness of the CHA, assisting with the distribution of the CHA survey, and leading the CHA small group follow up. Evaluation of the effectiveness of the program plan will occur after the CHA surveys are received and every six months. Limitations such as a lack of sustainability will be addressed through participatory approaches that fully engage the residents in the entire CHA process. As more residents are engaged, a greater awareness of the importance of the CHA can occur. Also, greater inclusivity may lead to an increased response rate on the CHA survey, and an increase in meaningful strategies to address health priorities can be developed and implemented.Master of Public Healt

Comparison of skewness-based salient event detector algorithms in speech

In this work, we compare two skewness-based salient event detector algorithms, which can detect transients in human speech signals. Speech transients are characterized by rapid changes in signal energy. The purpose of this study was to compare the identification of transients by two different methods based on skewness calculation in order to develop a method to be used in studying the processing of speech transients in the human brain. The first method, the skewness in variable time (SKV) finds transients using a cochlear model. The skewness of the energy distribution for a variable time window is implemented on artificial neural networks. The second method, the automatic segmentation method for transient detection (RoT) is more speech segmentation-based and developed for detecting transient speech segment ratio in spoken records. In the current study, the test corpus included Hungarian and English speech recorded from different speakers (2 male and 2 female for both languages). Results were compared by the F-measure, the Jaccard similarity index, and the Hamming distance. The results of the two algorithms were also tested against a hand-labeled corpus annotated by linguistic experts for an absolute assessment of the performance of the two methods. Transient detection was tested once for onset events alone and, separately, for onset and offset events together. The results show that in most cases, the RoT method works better on the expert labeled databases. Using F measure with +- 25ms window length the following results were obtained when all type of transient events were evaluated: 0,664 on English and 0,834 on Hungarian. Otherwise, the two methods identify the same stimulus features as the transients also coinciding with those hand-labeled by experts

Advanced pixel architectures for scientific image sensors

We present recent developments from two projects targeting advanced pixel architectures for scientific applications. Results are reported from FORTIS, a sensor demonstrating variants on a 4T pixel architecture. The variants include differences in pixel and diode size, the in-pixel source follower transistor size and the capacitance of the readout node to optimise for low noise and sensitivity to small amounts of charge. Results are also reported from TPAC, a complex pixel architecture with ~160 transistors per pixel. Both sensors were manufactured in the 0.18μm INMAPS process, which includes a special deep p-well layer and fabrication on a high resistivity epitaxial layer for improved charge collection efficiency

Rapid uranium-series age screening of carbonates by laser ablation mass spectrometry

AbstractUranium-series dating is a critical tool in quaternary geochronology, including paleoclimate work, archaeology and geomorphology. Laser ablation (LA) methods are not as precise as most isotope dilution methods, but can be used to generate calendar ages rapidly, expanding the range of dating tools that can be applied to late Pleistocene carbonates. Here, existing LA methods are revisited for corals (cold- and warm-water) and speleothems spanning the last 343 thousand years (ka). Measurement of the required isotopes (238U, 234U, 230Th and 232Th) is achieved by coupling a laser system to a multi-collector inductively-coupled-plasma mass spectrometer (MC-ICPMS) using a combination of a single central ion counter and an array of Faraday cups. Each sample analysis lasts for ∼4.3 min, and fifty samples can be measured in 12 h with an automated set up, after a day of sample preparation. The use of different standard materials and laser systems had no significant effect on method accuracy. Uncertainty on the measured (230Th/238U) activity ratios ranges from 5.4% to 7.6% for (230Th/238U) ratios equal to 0.7 and 0.1 respectively. Much of this uncertainty can be attributed to the heterogeneity of the standard material (230Th/238U) at the length scale of LA. A homogeneous standard material may therefore improve measurement uncertainty but is not a requirement for age-screening studies. The initial (234U/238U) of coral samples can be determined within ∼20‰, making it useful as a first indicator of open-system behaviour. For cold-water corals, success in determination of (232Th/238U) – which can affect final age accuracy – by LA depended strongly on sample heterogeneity. Age uncertainties (2 sigma) ranged from <0.8 ka at 0–10 ka, ∼1.5 ka at 20 ka to ∼15 ka at 125 ka. Thus, we have demonstrated that U-series dating by LA-MC-ICPMS can be usefully applied to a range of carbonate materials as a straightforward age-screening technique

A robust sound perception model suitable for neuromorphic implementation

Coath M, Sheik S, Chicca E, Indiveri G, Denham S, Wennekers T. A robust sound perception model suitable for neuromorphic implementation. Neuromorphic Engineering. 2014;7(278):1-10.We have recently demonstrated the emergence of dynamic feature sensitivity through exposure to formative stimuli in a real-time neuromorphic system implementing a hybrid analog/digital network of spiking neurons. This network, inspired by models of auditory processing in mammals, includes several mutually connected layers with distance-dependent transmission delays and learning in the form of spike timing dependent plasticity, which effects stimulus-driven changes in the network connectivity. Here we present results that demonstrate that the network is robust to a range of variations in the stimulus pattern, such as are found in naturalistic stimuli and neural responses. This robustness is a property critical to the development of realistic, electronic neuromorphic systems. We analyze the variability of the response of the network to “noisy” stimuli which allows us to characterize the acuity in information-theoretic terms. This provides an objective basis for the quantitative comparison of networks, their connectivity patterns, and learning strategies, which can inform future design decisions. We also show, using stimuli derived from speech samples, that the principles are robust to other challenges, such as variable presentation rate, that would have to be met by systems deployed in the real world. Finally we demonstrate the potential applicability of the approach to real sounds