Higher Tannaka duality

Dans cette thèse, nous prouvons un théorème de dualité de Tannaka pour les (infini, 1)-catégories. La dualité classique de Tannaka est une dualité entre certains groupes et catégories monoïdales munies d'une structure particulière. La dualité de Tannaka supérieure renvoie, elle, à une dualité entre certains champs en groupes dérivés et certaines (infini, 1)-catégories monoïdales munies d'une structure particulière. Cette dualité supérieure est définie sur les anneaux dérivés et englobe la théorie de dualité classique. Nous comparons la dualité de Tannaka supérieure à la théorie de dualité de Tannaka classique et portons une attention particulière à la dualité de Tannaka sur les corps. Dans ce dernier cas, cette théorie a une relation étroite avec la théorie des types d'homotopie schématique de Toën. Nous décrivons également trois applications de la théorie : les complexes parfaits, les motifs et leur analogue non-commutatif dû à Kontsevich.In this thesis we prove a Tannaka duality theorem for (infini, 1)-categories. Classical Tannaka duality is a duality between certain groups and certain monoidal categories endowed with particular structure. Higher Tannaka duality refers to a duality between certain derived group stacks and certain monoidal (infini, 1)-categories endowed with particular structure. This higher duality theorem is defined over derived rings and subsumes the classical statement. We compare the higher Tannaka duality to the classical theory and pay particular attention to higher Tannaka duality over fields. In the later case this theory has a close relationship with the theory of schematic homotopy types of Toën. We also describe three applications of our theory : perfect complexes and that of both motives and its non-commutative ana­logue due to Kontsevich

Domestic thermal upgrades, community action and energy saving: a three-year experimental study of prosperous households

A three-year field experiment was conducted with 185 prosperous households to assess whether behavioural interventions by a community environmental group during and after thermal upgrades (cavity wall and/or loft insulation) can achieve reductions in households’ energy use, including reductions in direct and indirect rebound. The engineering interventions on the thermal efficiency of dwellings appear effective in reducing energy use in both treatment and control groups: a direct rebound effect is estimated to be at most 40 per cent from the engineering interventions. However, across a range of measures of energy use, we observe no significant effect of the community behavioural intervention across the total lifetime of the project. Qualitative data collected on similar community groups suggests substantial constraints on their capacity to realise reductions in energy use amongst households

Guidelines for Designing Social Robots as Second Language Tutors

In recent years, it has been suggested that social robots have potential as tutors and educators for both children and adults. While robots have been shown to be effective in teaching knowledge and skill-based topics, we wish to explore how social robots can be used to tutor a second language to young children. As language learning relies on situated, grounded and social learning, in which interaction and repeated practice are central, social robots hold promise as educational tools for supporting second language learning. This paper surveys the developmental psychology of second language learning and suggests an agenda to study how core concepts of second language learning can be taught by a social robot. It suggests guidelines for designing robot tutors based on observations of second language learning in human–human scenarios, various technical aspects and early studies regarding the effectiveness of social robots as second language tutors

Initial effects of a community-based initiative for energy saving: an experimental analysis

Can community-based behavioural intervention reduce energy use in the home? We report on initial data from an ongoing matched case and control field experiment on energy saving. Household energy use in 175 households is measured using monitoring equipment, recording electrical power consumption and temperature. Participants in treatment and control groups received improvements to the thermal insulation of their homes. A behavioural intervention in the treatment group began with a 2 hour workshop on energy saving led by a community-based environmental group. We find some evidence of reductions in electrical power over the period of analysis, compared to the estimated counterfactual, but no evidence of reduced spatial heating or baseload power. The data are consistent with a substantial effect lasting over 3 months, although this cannot be inferred with confidence because of high variance. We explore the policy implications of the finding that a relatively modest level of community intervention has potentially substantial impact on energy use

Higher Tannaka duality

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