1,012,773 research outputs found

    A Domain-Independent Algorithm for Plan Adaptation

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    The paradigms of transformational planning, case-based planning, and plan debugging all involve a process known as plan adaptation - modifying or repairing an old plan so it solves a new problem. In this paper we provide a domain-independent algorithm for plan adaptation, demonstrate that it is sound, complete, and systematic, and compare it to other adaptation algorithms in the literature. Our approach is based on a view of planning as searching a graph of partial plans. Generative planning starts at the graph's root and moves from node to node using plan-refinement operators. In planning by adaptation, a library plan - an arbitrary node in the plan graph - is the starting point for the search, and the plan-adaptation algorithm can apply both the same refinement operators available to a generative planner and can also retract constraints and steps from the plan. Our algorithm's completeness ensures that the adaptation algorithm will eventually search the entire graph and its systematicity ensures that it will do so without redundantly searching any parts of the graph.Comment: See http://www.jair.org/ for any accompanying file

    Consonant Context Effects on Vowel Sensorimotor Adaptation

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    Speech sensorimotor adaptation is the short-term learning of modified articulator movements evoked through sensory-feedback perturbations. A common experimental method manipulates acoustic parameters, such as formant frequencies, using real time resynthesis of the participant\u27s speech to perturb auditory feedback. While some studies have examined phrases comprised of vowels, diphthongs, and semivowels, the bulk of research on auditory feedback-driven sensorimotor adaptation has focused on vowels in neutral contexts (/hVd/). The current study investigates coarticulatory influences of adjacent consonants on sensorimotor adaptation. The purpose is to evaluate differences in the adaptation effects for vowels in consonant environments that vary by place and manner of articulation. In particular, we addressed the hypothesis that contexts with greater intra-articulator coarticulation and more static articulatory postures (alveolars and fricatives) offer greater resistance to vowel adaptation than contexts with primarily inter-articulator coarticulation and more dynamic articulatory patterns (bilabials and stops). Participants completed formant perturbation-driven vowel adaptation experiments for varying CVCs. Results from discrete formant measures at the vowel midpoint were generally consistent with the hypothesis. Analyses of more complete formant trajectories suggest that adaptation can also (or alternatively) influence formant onsets, offsets, and transitions, resulting in complex formant pattern changes that may reflect modifications to consonant articulatio

    Lags and Leads in Life Satisfaction: A Test of the Baseline Hypothesis

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    We look for evidence of habituation in twenty waves of German panel data: do individuals, after life and labour market events, tend to return to some baseline level of well-being? Although the strongest life satisfaction effect is often at the time of the event, we find significant lag and lead effects. We cannot reject the hypothesis of complete adaptation to marriage, divorce, widowhood, birth of child, and layoff. However, there is little evidence of adaptation to unemployment. Men are somewhat more affected by labour market events (unemployment and layoffs) than are women, but in general the patterns of anticipation and adaptation are remarkably similar by sex.life satisfaction, anticipation, adaptation, baseline satisfaction, labour market and lifeevents

    Free Search and Particle Swarm Optimisation applied to Non-constrained Test

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    This article presents an evaluation of Particle Swarm Optimisation (PSO) with variable inertia weight and Free Search (FS) with variable neighbour space applied to nonconstrained numerical test. The objectives are to assess how high convergence speed reflects on adaptation to various test problems and to identify possible balance between convergence speed and adaptation, which allows the algorithms to complete successfully the process of search on heterogeneous tasks with limited computational resources within a reasonable finite time and with acceptable for engineering purposes precision. Modification strategies of both algorithms are compared in terms of their ability for search space exploration. Five numerical tests are explored. Achieved experimental results are presented and analysed

    Back to baseline in Britain: Adaptation in the BHPS

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    We look for evidence of adaptation of well-being to major life events in sixteen waves of British panel data. We find that, with the exception of unemployment, adaptation to other life events including marriage, divorce, birth of a child and widowhood is rapid and complete. These findings are remarkably similar to those found in previous analysis of German panel data. Equally, the time profiles of well-being as measured by life satisfaction data are very close to those from the analysis of a twelve-item scale of psychological functioning. As such, the phenomenon of adaptation may be a general one, rather than being only found in German data or using single-item measures. Last, we uncover some systematic differences in adaptation profiles according to "Big Five" personality measures.Life Satisfaction ; anticipation ; adaptation ; baseline satisfaction ; labour market and life events

    Assessing Retinal Structure In Complete Congenital Stationary Night Blindness and Oguchi Disease

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    Purpose To examine retinal structure and changes in photoreceptor intensity after dark adaptation in patients with complete congenital stationary night blindness and Oguchi disease. Design Prospective, observational case series. Methods We recruited 3 patients with complete congenital stationary night blindness caused by mutations in GRM6, 2 brothers with Oguchi disease caused by mutations in GRK1, and 1 normal control. Retinal thickness was measured from optical coherence tomography images. Integrity of the rod and cone mosaic was assessed using adaptive optics scanning light ophthalmoscopy. We imaged 5 of the patients after a period of dark adaptation and examined layer reflectivity on optical coherence tomography in a patient with Oguchi disease under light- and dark-adapted conditions. Results Retinal thickness was reduced in the parafoveal region in patients with GRM6 mutations as a result of decreased thickness of the inner retinal layers. All patients had normal photoreceptor density at all locations analyzed. On removal from dark adaptation, the intensity of the rods (but not cones) in the patients with Oguchi disease gradually and significantly increased. In 1 Oguchi disease patient, the outer segment layer contrast on optical coherence tomography was 4-fold higher under dark-adapted versus light-adapted conditions. Conclusions The selective thinning of the inner retinal layers in patients with GRM6 mutations suggests either reduced bipolar or ganglion cell numbers or altered synaptic structure in the inner retina. Our finding that rods, but not cones, change intensity after dark adaptation suggests that fundus changes in Oguchi disease are the result of changes within the rods as opposed to changes at a different retinal locus

    Inter-Temporal Investment in Climate Change Adaptation and Mitigation

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    Currently, different dimensions of mitigation strategies have been investigated in policy analysis. However, ambitious mitigation action aiming at reducing future climate change will not prevent much climate change before mid-century. Short-term and medium-term temperature as well as associated damages cannot be avoided completely. Increasingly there appears to be recognition of the need to simultaneously implement adaptation and mitigation. However, the optimal combination between adaptation and mitigation that can best address climate change over time is still an open question. Literature base is rather small, yet very diverse and inconsistent in conclusions. In this paper, we do an exploration of the temporal optimal investment mix between adaptation and mitigation and their relative contributions to climate change damage reduction. By proposing a conceptual framework that integrates both strategies and developing a more complete integrated assessment model, the temporal investment allocation between adaptation and mitigation is identified. Results suggest that adaptation is an effective climate change damages reduction strategy and a complement to mitigation. Adaptation investment tackles the short run reduction of damages in the first 250 years while mitigation dominates from thereon.Climate Change Damages, Adaptation, Mitigation, Temporal Investment, Integrated Assessment Model, Environmental Economics and Policy, Resource /Energy Economics and Policy, Risk and Uncertainty, Q54, Q58,
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