234 research outputs found

    Tag based Bayesian latent class models for movies : economic theory reaches out to big data science

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    For the past 50 years, cultural economics has developed as an independent research specialism. At its core are the creative industries and the peculiar economics associated with them, central to which is a tension that arises from the notion that creative goods need to be experienced before an assessment can be made about the utility they deliver to the consumer. In this they differ from the standard private good that forms the basis of demand theory in economic textbooks, in which utility is known ex ante. Furthermore, creative goods are typically complex in composition and subject to heterogeneous and shifting consumer preferences. In response to this, models of linear optimization, rational addiction and Bayesian learning have been applied to better understand consumer decision- making, belief formation and revision. While valuable, these approaches do not lend themselves to forming verifiable hypothesis for the critical reason that they by-pass an essential aspect of creative products: namely, that of novelty. In contrast, computer sciences, and more specifically recommender theory, embrace creative products as a study object. Being items of online transactions, users of creative products share opinions on a massive scale and in doing so generate a flow of data driven research. Not limited by the multiple assumptions made in economic theory, data analysts deal with this type of commodity in a less constrained way, incorporating the variety of item characteristics, as well as their co-use by agents. They apply statistical techniques supporting big data, such as clustering, latent class analysis or singular value decomposition. This thesis is drawn from both disciplines, comparing models, methods and data sets. Based upon movie consumption, the work contrasts bottom-up versus top-down approaches, individual versus collective data, distance measures versus the utility-based comparisons. Rooted in Bayesian latent class models, a synthesis is formed, supported by the random utility theory and recommender algorithm methods. The Bayesian approach makes explicit the experience good nature of creative goods by formulating the prior uncertainty of users towards both movie features and preferences. The latent class method, thus, infers the heterogeneous aspect of preferences, while its dynamic variant- the latent Markov model - gets around one of the main paradoxes in studying creative products: how to analyse taste dynamics when confronted with a good that is novel at each decision point. Generated by mainly movie-user-rating and movie-user-tag triplets, collected from the Movielens recommender system and made available as open data for research by the GroupLens research team, this study of preference patterns formation for creative goods is drawn from individual level data

    Adaptive motivational signals in the anterior cingulate cortex and ventral tegmental area

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    This thesis focused on the role of the anterior cingulate cortex’s (ACC) interactions with the dopaminergic neurons in the ventral tegmental area (VTA) during adaptive behaviour. The overall question guiding this work was: how does information gained during goal pursuit modify and motivate subsequent behaviour? This larger question was operationalized as two projects: (i) to determine whether cortical influence over the dopaminergic midbrain is a mechanism by which ACC signals are implemented as VTA motivation signals; and (ii) to determine the interplay between the ACC and VTA during the initiation and maintenance of behavioural change. In the first project, we monitored and modelled ACC and VTA local field potentials of rats running laps of varying physical difficulty for fixed rewards. The effortful condition required rats to climb over a 30-cm barrier, whereas no barrier was present under the non-effortful condition. The key finding was that ACCVTA 4-12 Hz signalling increased in trials when the lap was easier than expected. Importantly, this increase was significantly correlated with, but not confounded by, changes in motivation, as measured by running speed. The findings of this first project indicated that the ACC-VTA circuit is a plausible mechanism by which behaviour is modified. This led us to ask whether changes in the ACC-VTA circuit are related to the initiation and persistence of behavioural change. To assess the interplay between the ACC and VTA during the initiation and persistence of behavioural change, we monitored ACC single units and LFPs as well as LFPs in VTA of rats performing a cost-benefit foraging task with changing contingencies. Through a combination of behavioural, electrophysiological, and modelling analyses, we found that the initiation of exploratory behaviour and the persistence of behavioural change were associated with ACC VTA signalling. Additionally, we characterized the content of ACC neuronal task models, and showed that ensembles of ACC neurons encode simple actions and values. This was important because, despite the longstanding assumption that the ACC encodes neuronal models of the task at hand, the content of those internal representations remained unclear. Furthermore, we demonstrated that value-coding elements of ACC neuronal task models are particularly influenced by the VTA. This is important because it suggests that mesocortical dopaminergic signalling is a means by which ACC models of the task at hand could be both initiated and modified. The thesis concludes by presenting a novel incentive-salience, task-model onset theory of ACC function

    Dysfunction in the anterior cingulate cortex and the ventral tegmental area in relation to decision making and motivation in an animal model of schizophrenia

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    Difficulties in decision-making and motivation can impact functional outcomes in schizophrenia. Two brain regions that play a role in decision-making and motivation are the ACC and VTA, with both showing dysfunction in the disease. In order to investigate this dysfunction in more detail we used the MIA animal model of schizophrenia, which models the development of schizophrenia and the associated brain abnormalities observed in human patients. The aim of this study was to investigate decision-making and motivation in the MIA model and whether any changes relate to deficits observed in schizophrenia. Additionally, we investigated if there was any dysfunction in neuronal activity within and between the ACC and VTA, and whether any abnormalities are related to any of the behavioural deficits observed. To these ends neuronal activity in the ACC and VTA was recorded whilst the MIA and control rats ran in a figure-eight maze that offered a choice between a high cost and high reward, or a low cost and low reward option. Halfway through each session the location of the choices reversed. We found that decision-making in the MIA rats was affected by memory deficits on the first trial of a session, with rats apparently failing to recall the configuration from the end of the previous session. Memory deficits or behavioural inflexibility also resulted in a lack of anticipatory choices prior to the reversal in the MIA rats. This reflected either a failure to recall the reversal or inability to adapt to the approaching reversal. Following the reversal, behavioural inflexibility resulted in the MIA rats continuing to select the arm that had previously contained the preferred choice post-reversal. We observed an increase in beta activity in the ACC including abnormal synchrony of ACC neurons to the beta activity throughout the task, which may link to the increased behavioural inflexibility of the MIA rats. At the decision point we observed abnormal ACC-VTA coherence in the delta frequency band immediately post-reversal when the impact of behavioural inflexibility was the greatest. The MIA rats also displayed increased vicarious trial and error, suggesting increased deliberative decision-making likely due to avolition or due to difficulties in mentally exploring possible outcomes because of memory deficits. An avolition explanation was supported as MIA rats had an increase in ACC neurons encoding the cost and low-cost choice, indicating an increased perception of cost and increased preference for the low-cost choice compared to controls, which would have reduced motivation. Additionally, a general decrease in theta activity in the VTA of the MIA rats suggests a decrease in the motivation signal. ACC neurons also showed abnormal synchrony to the VTA theta activity suggesting that the connectivity between the two regions is involved in this dysfunction. We therefore modelled difficulties in decision-making and motivation observed in schizophrenia and linked these deficits to dysfunction within and between the ACC and VTA, increasing and deepening our understanding of the potential neurological basis of these behavioural deficits in schizophrenia

    Inclined ergometer to enhance FES-assisted indoor rowing exercise performance

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    Improving the FES-assisted indoor rowing exercise (FES-rowing) performance enables the spinal cord injury (SCI) people to perform hybrid FES-exercise in a higher level of intensity. High level of exercise volume and intensity can play a big role in prevention of cardiovascular disease, type 2 diabetes and obesity which is a significant threat to the health of people with chronic SCI. FES-rowing can be enhanced to achieved the high level exercise through the arrangement of the rowing ergometer. In this paper, the performance of FES-rowing using an adjustable inclined rowing ergometer is investigated. Two different methods to enhance the FES-rowing performance using inclined ergometer are implemented. A model of the adjustable inclined ergometer and humanoid are developed using the Visual Nastran (vN4D) software environment and validated by the experimental work. Fuzzy logic control is implemented to control the knee and elbow trajectories for smooth rowing manoeuvre. The generated level of electrical stimulations for activation of quadriceps and hamstrings muscles are recorded and analysed. The FES-rowing efficiency for both methods have been defined and illustrated. The results show the inclined ergometer with upper body effort is the best performance in enhancing the FES-rowing

    Six Sigma for Non-Profit Organizations

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    Although non-profit organizations, such as healthcare, education, recreation, welfare, religious and culture agencies rarely think of themselves as business, they share a lot of traits with for-profit businesses. They must attract customers, must generate and manage income, manage staff, buildings, machinery, and provide services that the customer desires. There has been recognition in the world for the need for quality management practices in non-profit organizations. The United States, United Kingdom, Europe, Austria, the Netherlands, Asia and Eastern Europe all have quality awards for non-profit agencies. The guidelines for the Baldrige National Award in the United States are very similar to the quality awards for non-profits throughout the world. Six Sigma tools were chosen for use with Midwestern Church (not real name) in preference to ISO9001 and the Baldrige criteria. The desire was to start with a small project in which there was a good chance for success in hopes that future projects would be attempted. ISO9001 and the Baldrige criteria were too large of a scope for an organization without an initial quality management system. A team of support staff at Midwestern Church chose inter-staff communications as their improvement project. When the communication process was mapped, it was found that e-mail was the main method of communication and business was rarely discussed at staff meetings, rather Bible study occurred. Three improvements were suggested: Time deadlines were added in the subject lines of e-mails of the team members MicroSoft Outlook training to optimize the e-mail system was offered to all staff members Staff meetings were structured to discuss business The first two improvements were partially implemented and slight improvements in communications were made among the team members as a result. Because there was little support from upper management (clergy), there was limited success in the first two improvements and the third was never implemented. Despite this it is believed that the project was successful. Some staff members who were not part of the first training have requested and received Outlook training. Two focus group using techniques similar to those used in this project are being formed to obtain attendee (customer) input concerning worship services that are losing attendance

    Attention Consumers of Justice: Court Reform Should Begin in the Classroom Part II

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    Poboljšanje izvedbe i kvalitete procesa proizvodnje namještaja primjenom metodologije Six Sigma

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    The main aim of this paper is to illustrate the application of selected methods and procedures in the implementation of the Six Sigma Methodology in the furniture manufacturing processes, specifically in the wood veneer pressing, to verify the application and to evaluate the benefits of using selected methods and procedures through a series of step DMAIC process improvement. The application of selected methods and tools within the Six Sigma Methodology, such as DPMO, efficiency and sigma levels, project charter, histogram of mistakes caused by the application of the adhesive, the SIPOC plot mapping process, reaction plans, Ishikawa diagram and control diagrams bring the system and clarity of measurable results into project management for process improvement and process change. The benefits of their use are the cost savings and performance improvement processes.Glavni je cilj ovog rada prikazati provedbu odabranih metoda i postupaka pri primjeni Six Sigma metodologije u proizvodnji namještaja. To se posebice odnosi na provjeru primjene i procjenu prednosti korištenja odabranih metoda i postupaka pri prešanju furnira unutar niz koraka za poboljšanje DMAIC procesa. Primjena odabranih metoda i alata u sklopu metodologije Six Sigma, kao što su DPMO, učinkovitost i sigma razine, projektna povelja, histogram grešaka uzrokovanih primjenom ljepila, proces mapiranja SIPOC, reakcijski planovi, Ishikawa dijagram i kontrolni dijagrami, uvodi sustav i jasnoću mjerljivih rezultata u upravljanje projektima radi poboljšanja i promjene procesa. Prednosti njihove uporabe jesu smanjenje troškova i poboljšanje proizvodnog procesa

    ‘High risk’ clinical and inflammatory clusters in COPD of Chinese descent

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordIntroduction COPD is a heterogeneous disease demonstrating inter-individual variation. A high COPD prevalence in Chinese populations is described but little is known about disease clusters and prognostic outcomes in the Chinese population across South-East Asia. We aim to determine if clusters of Chinese patients with COPD exist and their association with systemic inflammation and clinical outcomes. Methods Chinese patients with stable COPD were prospectively recruited into two cohorts (derivation and validation) from six hospitals across three South-East Asian countries (Singapore, Malaysia and Hong Kong; n=1,480). Each patient was followed over two-years. Clinical data (including co-morbidities) were employed in unsupervised hierarchical clustering (followed by validation) to determine the existence of patient clusters and their prognostic outcome. Accompanying systemic cytokine assessments were performed in a subset (n=336) of COPD patients to determine if inflammatory patterns and associated networks characterised the derived clusters. Results Five patient clusters were identified including (1) Ex-tuberculosis (2) Diabetic (3) Low co-morbidity: low-risk (4) Low co-morbidity: high-risk and (5) cardiovascular. The ‘cardiovascular’ and ‘ex-tuberculosis’ clusters demonstrate highest mortality (independent of GOLD assessment) and illustrate diverse cytokine patterns with complex inflammatory networks. Conclusions We describe novel ‘clusters’ of Chinese COPD patients, two of which represent ‘high-risk’ clusters. The ‘cardiovascular’ and ‘ex-tuberculosis’ patient clusters exhibit high mortality, significant inflammation and complex cytokine networks. Clinical and inflammatory risk stratification of Chinese patients with COPD should be considered for targeted intervention to improve disease outcomes.Singapore Ministry of Health - National Medical Research CouncilSingapore Ministry of EducationNanyang Technological University, SingaporeEngineering and Physical Sciences Research Council (EPSRC

    A New Consumer Remedy: Product Recall

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