34,664 research outputs found
Neutrino Mass and Oscillations
Current evidence for neutrino oscillation is reviewed, some areas for closer
investigation are suggested, and a plausible future experimental program is
summarized.Comment: Text of talk presented at Lepton-Photon 99 Conference, Stanford, Aug.
9-14, 1999; to be published in the Proceedings. LaTeX, 22 pages, 4 figures, 6
Postscript file
Acquiring Correct Knowledge for Natural Language Generation
Natural language generation (NLG) systems are computer software systems that
produce texts in English and other human languages, often from non-linguistic
input data. NLG systems, like most AI systems, need substantial amounts of
knowledge. However, our experience in two NLG projects suggests that it is
difficult to acquire correct knowledge for NLG systems; indeed, every knowledge
acquisition (KA) technique we tried had significant problems. In general terms,
these problems were due to the complexity, novelty, and poorly understood
nature of the tasks our systems attempted, and were worsened by the fact that
people write so differently. This meant in particular that corpus-based KA
approaches suffered because it was impossible to assemble a sizable corpus of
high-quality consistent manually written texts in our domains; and structured
expert-oriented KA techniques suffered because experts disagreed and because we
could not get enough information about special and unusual cases to build
robust systems. We believe that such problems are likely to affect many other
NLG systems as well. In the long term, we hope that new KA techniques may
emerge to help NLG system builders. In the shorter term, we believe that
understanding how individual KA techniques can fail, and using a mixture of
different KA techniques with different strengths and weaknesses, can help
developers acquire NLG knowledge that is mostly correct
Associations between health and different types of environmental incivility : a Scotland-wide study
Objectives: Concern about the impact of the environment on health and well being has tended to focuson the physical effects of exposure to toxic and infectious substances, and on the impact of large scale infrastructures. Less attention has been paid to the possible psychosocial consequences of people's subjective perceptions of their everyday, street level environment, such as the incidence of litter and graffiti. As little is known about the potential relative importance for health of perceptions of different types of environmental incivility, a module was developed for inclusion in the 2004 Scottish Social Attitudes survey in order to investigate this relationship. Study design: A random sample of 1637 adults living across a range of neighbourhoods throughout Scotland was interviewed. Methods: Respondents were asked to rate their local area on a range of possible environmental incivilities. These incivilities were subsequently grouped into three domains: (i) street level incivilities (e.g. litter, graffiti); (ii) large scale infrastructural incivilities (e.g. telephone masts); and (iii) the absence of environmental goods (e.g. safe play areas for children). For each of the three domains, the authors examined the degree to which they were thought to pose a problem locally, and how far these perceptions varied between those living in deprived areas and those living in less deprived areas. Subsequently, the relationships between these perceptions and self assessed health and health behaviours were explored, after controlling for gender, age and social class. Results: Respondents with the highest levels of perceived street level incivilities were almost twice aslikely as those who perceived the lowest levels of street level incivilities to report frequent feelings of anxiety and depression. Perceived absence of environmental goods was associated with increased anxiety (2.5 times more likely) and depression (90% more likely), and a 50% increased likelihood of being a smoker. Few associations with health were observed for perceptions of large scale infrastructural incivilities. Conclusions: Environmental policy needs to give more priority to reducing the incidence of street levelincivilities and the absence of environmental goods, both of which appear to be more important for health than perceptions of large scale infrastructural incivilities
Household technology acceptance heterogeneity in computer adoption
Technology policy analysis and implementation relies on knowledge and understanding of the "adoption gap" in information technologies among different groups of consumers. Factors that explain the residential "digital divide" also need to be identified and quantified. Through the application of survey data we provide an enhanced understanding of the key factors involved in the choice of residential computer adoption. These choices are analysed using a discrete choice model that reveals that sociodemographic factors strongly influence the adoption of the residential computer. Moreover, we apply the basic findings of the Technology Adoption Model (TAM) into the discrete choice framework heteroscedastically to deepen our understanding of why some households choose not to have computers; above and beyond what may be explained by socio-demography alone. Generally, we find that computer adoption is sensitive to household digital division measures and that the model fit improves with the heteroscedastic addition of the TAM factors. These findings are important for market planners and policymakers who wish to understand and quantify the impact of these factors on the digital divide across different household types, as defined by the TAM model
South Pacific convergence zone and global scale circulations (Jul. 1987 - Jul. 1991). Observational and modeling studies of heat, moisture, precipitation, and global-scale circulation patterns (Jul. 1990 - Jul. 1993)
Several research projects were worked on between August 1990 and May 1991. Topics covered included observational and modeling studies of relationships between tropical heat sources and subtropical jet streams, the intraseasonal (30 to 60 day) oscillation near the equator, and precipitation over tropical oceans. Current research activities and plans for the coming year are outlined
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