A Methodology for the Development of Recurrent Networks for Sequence Processing Tasks

Artificial neural networks are increasingly being used for dealing with real world applications. Many of these (e.g. speech recognition) are based on an ability to perform sequence processing. A class of artificial neural networks, known as recurrent networks, have architectures which incorporate feedback connections. This in turn allows the development of a memory mechanism to allow sequence processing to occur. A large number of recurrent network models have been developed, together with modifications of existing architectures and learning rules. However there has been comparatively little effort made to compare the performance of these models relative to each other. Such comparative studies would show differences in performance between networks and allow an examination of what features of a network give rise to desirable behaviours such as faster learning and superior generalisation ability. This thesis describes the results of a number of existing comparative studies and the results of new research. Three different recurrent networks, both in their original form and with modifications, are tested with four different sequence processing tasks. The results of this research clearly show that recurrent networks vary widely in terms of their performance and lead to a methodology based on the following conclusions: </br

Sovereign Net Worth: An Analytical Framework

The Fiscal Responsibility Act requires the Crown to articulate targets for a series of fiscal variables, including net worth. Given the dramatic improvement in the fiscal position in recent years, a critical policy question relates to how (and which) measures of Crown net worth should be targeted. This paper sets out a framework for targeting Crown net worth. It does so by supplementing the GAAP-based measure with forward-looking information about spending and tax revenue. The paper argues that targeting net worth for the Crown requires the estimation of a path, rather than a static level.

Some considerations on a new edition of the expostulatio spongiae

Note on Julián González-Barrera,  <em>Expostulatio Spongiae. Fuego cruzado en el nombre de</em><br /><em>Lope</em>, Reichenberger, Kassel, 2011

Master of Science

thesisRapid reconnaissance methodologies are useful in investigations of deep-sea sediments, as they require little time for analysis and small amounts of sample material. This is especially useful for new studies of old cores drilled decades ago, which have become quite depleted. Both Quantitative Evaluation of Minerals by SCANning electron microscopy (QEMSCAN®) and handheld X-ray Fluorescence (XRF) instruments are ideally suited for such studies, as samples can be as small as 1 cc, and both are capable of rapidly detecting trace components within these small samples. Such speed allows multiple core horizons of interest to be analyzed for studies in paleoclimatology, extraterrestrial fluxes, and sediment velocity. Grain-size and mineralogy of Ocean Drilling Program (ODP) Hole 722B are investigated using QEMSCAN® and compared to standard methodologies. QEMSCAN®-based grain-size, which indicates changes in paleowind strength due to the Indian Ocean summer monsoon for the last 200 ka, correlates well with previous data. Mineralogy is found to not correlate as well, however: dolomite has a good correlation, clays and feldspars a medium correlation, and quartz a poor correlation. Handheld XRF is used for rapid reconnaissance of LL44-GPC3 and Canterbury Basin sediments from IODP Leg 317. Nickel-rich sediments are found in LL44-GPC3 at ~11.1 mbsf and ~12.4 mbsf, corresponding to layers known to have extraterrestrial nickel-rich spinel and known impact events at Chesapeake Bay and Popigai. Canterbury Basin sediment elemental peak counts are compared to velocity measurements of the same sediment, to establish the first conclusive iv demonstration of carbonate cementation increasing velocities in siliciclastic sediments. For each sample, the handheld XRF measurement establishes its position on the sand-shale continuum, as well as the relative amount of calcite cementation. Determination of cementation occurring in porous sands with high velocities is shown, and linked to fluid flow in the region. Both studies illustrate the usefulness of handheld XRF as a reconnaissance methodology for detecting extremely subtle mineralogical signals within deep-sea sediments

Validating Geologic Storage Potential in the Midwestern USA through Multiple Field Demonstrations

AbstractThe Midwestern Regional Carbon Sequestration Partnership (MRCSP) is implementing an integrated effort to validate the geologic storage potential in the Midwestern states within the USA through multiple field demonstrations. Validation of the geologic storage potential in this area requires regional geologic exploration along with site-specific demonstrations of CO2 injection and monitoring. These demonstrations are being conducted in collaboration with energy companies in Appalachian Basin, Michigan Basin, and Cincinnati Arch geologic regions. Each field test incorporates extensive characterization, reservoir modeling, permitting, outreach, injection and monitoring in a deep saline reservoir setting. The progress that has been achieved during the past year, including the evaluation of injection at two test sites, is presented

The cognitive antecedents of psychosis-like (anomalous) experiences: variance within a stratified quota sample of the general population

In the general population, psychosis-like experiences have been extensively studied under the psychometric rubric of schizotypy (psychosis-proneness). As such, Phase 1 of this thesis aimed to assess the distribution of schizotypal traits and associated personality correlates displayed within a quota sample of the general population stratified by Gender and Ageband, the emphasis being upon anomalous experiences (positive schizotypy). Respondents (N = 130) completed a battery of established self-report measures assessing thirteen areas of personal experience. Correlational analysis revealed that eleven of the measures of ostensibly anomalous experiences possessed significant intercorrelations. Subsequent principal components analysis identified three factors accounting for 64.91% of the total variance; the factor accounting for the greatest proportion of variance (42.97%) was interpreted as representing a psychological disposition towards reporting ‘Anomalous Cognitions’. The other two factors are named ‘Lifeview System’ (12.60% of total variance) and ‘Social Adaptation Skills’ (9.34% of total variance). From the principal factor inclusion criteria for Phase 2 of the research are explicated. No significant mean Gender differences were revealed for the six self-report measures that provided unique contributions toward anomalous cognitions, the two self-report measures that uniquely contributed toward a lifeview system, or for the single self-report measure that uniquely contributed toward social adaptation skills. Additionally, four of the nine self-report measures which provided unique factorial contributions generated significant mean differences between Agebands, with a further three providing trends toward significant mean differences. Implications for the role of anomalous cognitions, a framework for a lifeview system, and social adaptation skills with regard to psychosis-proneness are discussed. From the primary factor (anomalous cognitions), three experimental groups were identified for cognitive testing: respondents scoring 1) ≤ 20th percentile; 2) 10% ± the mean; and 3) ≥ 80th percentile. This procedure provided a total of 78 participants (three x 26) for Phase 2 testing. Phase 2 of this thesis sought to identify some of the cognitive mechanisms underpinning subclinical anomalous cognitions with a view to deciphering which measures best predicted experimental group membership. A comprehensive literature review highlighted six domains of cognition, five accompanying self-report measures, and two measures of intelligence functioning (verbal and fluid/visuoconstructive), which, following previous research, were utilised as covariate measures. Based on prescribed delineation points, participants were allocated, according to scores on the primary factor from Phase 1, to one of three experimental groups (low-, mid, and high-anomalous cognitions). Of the six cognitive domains—1) sustained visual attention; 2) false (illusory) memory; 3) probability reasoning (decision making); 4) object recognition; 5) reality monitoring; and 6) self-monitoring—four succeeded in eliciting significant mean differences between experimental groups with the noted exceptions of sustained visual attention and self-monitoring. Subsequent canonical discriminant analyses identified that the best predictors of XPG membership were the number of critical lures recognised on the false memory test, the number of correct responses and confidence when uncertain on the object recognition test, plus two self-report measures pertaining to comorbid psychopathology and the vividness of visual imagery. In light of previous research, the inclusion of fasle (illusory) memory biases, the comorbidity of mental pathology (especially, depressive and anxiety-related symptoms), and the vividness of visual imagery are unsurprising; however, the two object recognition variables (the ‘number of correct responses’ and ‘confidence when uncertain’) offer exciting avenues for future research into the continuum of psychosis. Moreover, the ‘confidence when uncertain’ data from the object recognition test (perceptual) and the probability reasoning (decision making) data from the Beads test suggest that cognitive underconfidence may well be an enduring personality disposition in those reporting elevated levels of anomalous cognitions, including positive and disorganised schizotypal personality traits. The results of Phase 2 add confirmatory evidence to previous research suggestive of memory and perceptual biases plus comorbid psychopathology and the vividness of visual imagery as being integral to the psychogenesis of psychosis-like (anomalous) symptomatology

Kinetic parameter estimation from TGA: Optimal design of TGA experiments

This work presents a general methodology to determine kinetic models of solid thermal decomposition with thermogravimetric analysis (TGA) instruments. The goal is to determine a simple and robust kinetic model for a given solid with the minimum of TGA experiments. From this last point of view, this work can be seen as an attempt to find the optimal design of TGA experiments for kinetic modelling. Two computation tools were developed. The first is a nonlinear parameter estimation procedure for identifying parameters in nonlinear dynamical models. The second tool computes the thermogravimetric experiment (here, the programmed temperature profile applied to the thermobalance) required in order to identify the best kinetic parameters, i.e. parameters with a higher statistical reliability. The combination of the two tools can be integrated in an iterative approach generally called sequential strategy. The application concerns the thermal degradation of cardboard in a Setaram TGA instrument and the results that are presented demonstrate the improvements in the kinetic parameter estimation process