53,932 research outputs found

    Hierarchical testing designs for pattern recognition

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    We explore the theoretical foundations of a ``twenty questions'' approach to pattern recognition. The object of the analysis is the computational process itself rather than probability distributions (Bayesian inference) or decision boundaries (statistical learning). Our formulation is motivated by applications to scene interpretation in which there are a great many possible explanations for the data, one (``background'') is statistically dominant, and it is imperative to restrict intensive computation to genuinely ambiguous regions. The focus here is then on pattern filtering: Given a large set Y of possible patterns or explanations, narrow down the true one Y to a small (random) subset \hat Y\subsetY of ``detected'' patterns to be subjected to further, more intense, processing. To this end, we consider a family of hypothesis tests for Y\in A versus the nonspecific alternatives Y\in A^c. Each test has null type I error and the candidate sets A\subsetY are arranged in a hierarchy of nested partitions. These tests are then characterized by scope (|A|), power (or type II error) and algorithmic cost. We consider sequential testing strategies in which decisions are made iteratively, based on past outcomes, about which test to perform next and when to stop testing. The set \hat Y is then taken to be the set of patterns that have not been ruled out by the tests performed. The total cost of a strategy is the sum of the ``testing cost'' and the ``postprocessing cost'' (proportional to |\hat Y|) and the corresponding optimization problem is analyzed.Comment: Published at http://dx.doi.org/10.1214/009053605000000174 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Data mining as a tool for environmental scientists

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    Over recent years a huge library of data mining algorithms has been developed to tackle a variety of problems in fields such as medical imaging and network traffic analysis. Many of these techniques are far more flexible than more classical modelling approaches and could be usefully applied to data-rich environmental problems. Certain techniques such as Artificial Neural Networks, Clustering, Case-Based Reasoning and more recently Bayesian Decision Networks have found application in environmental modelling while other methods, for example classification and association rule extraction, have not yet been taken up on any wide scale. We propose that these and other data mining techniques could be usefully applied to difficult problems in the field. This paper introduces several data mining concepts and briefly discusses their application to environmental modelling, where data may be sparse, incomplete, or heterogenous

    Is the Welfare State Sustainable? Experimental Evidence on Citizens' Preferences for Redistribution

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    The sustainability of the welfare state ultimately depends on citizens’ preferences for income redistribution. They are elicited through a Discrete Choice Experiment performed in 2008 in Switzerland. Attributes are redistribution as GDP share, its uses (the unemployed, old-age pensioners, people with ill health etc.), and nationality of beneficiary. Estimated marginal willingness to pay (WTP) is positive among those who deem benefits too low, and negative otherwise. However, even those who state that government should reduce income inequality exhibit a negative WTP on average. The major finding is that estimated average WTP is maximum at 21% of GDP, clearly below the current value of 25%. Thus, the present Swiss welfare state does not appear sustainable.income redistribution, welfare state, sustainability, preferences, willingness to pay, discrete choice experiments

    Summary report on sensory-related socio-economic and sensory science literature about organic food products

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    Organic food’s initial attraction to the public was that it was perceived to be healthier and tastier, but scientists and policy makers have mainly stressed the benefits to the environment of organic and sustainable farming. Scientific support for marketing actions addressed to those who want to be healthier and who want to enjoy better taste, and are willing to pay more for these benefits is scarce. Past research has produced little clear evidence about the importance of sensory characteristics such as taste, smell, appearance etc in consumers’ preferences with regard to organic food. The Ecropolis project, funded by the E.U., was set up with the aim of investigating the role of the senses in consumers’ preferences regarding organic food, and leading to research into how best to satisfy those preferences. This deliverable is aimed at providing a solid basis for such research with an in-depth review of, and two reports on, the relevant scientific literature. The first report (Annex I) regards what consumers expect from organic products in terms of taste, smell, appearance, etc and how these expectations are (or are not) met; the second is about the science of the senses (Annex II). The first project tasks included creating and agreeing on a glossary of terms, deciding on search criteria (key words, etc.), setting up a bibliographical data base, preparing then circulating the above-mentioned reports, and finally preparing a summary of the reports. The report on consumers expectations highlights the suggestion that while organic food has traditionally been marketed through specialized retailers, its market share will only grow significantly if it is promoted by multiple retailers. Research literature from all over the world seems to agree in indicating that consumers’ choices are largely motivated by health, the environment, price and social status. Other considerations include ethics, the localness of the product and lifestyle choices. The literature also indicates that the organic market will expand significantly only if consumers are more willing, and able, to recognize quality, but this presents serious issues. When buying the product they cannot personally verify its quality and genuineness and thus must rely on regulation and inspection bodies. The recognition of quality can also be encouraged by effective communication by producers and retailers through appropriate branding, labelling and presentation. There are connections between this information and questions of sense perception, but researchers disagree about how important the latter is in influencing the customer, and in which ways it does so. The following report focuses, in fact, on the science of the senses, which tries to analyze in detail people’s responses to food, despite the many potential pitfalls in carrying out the research which might influence the reliability of the results. There is broad agreement on two points: - there is no proof that organic food is more nutritious or safer, and - most studies that have compared the taste and organoleptic quality of organic andconventional foods report no consistent or significant differences between organic and conventional produce. Therefore, claiming that all organic food tastes different from all conventional food would not be correct. However, among the well-designed studies with respect to fruits and vegetables that have found differences, the vast majority favour organic produce. Organic produce tends to store better and has longer shelf life, probably because of lower levels of nitrates and higher average levels of antioxidants. The former can accelerate food spoilage, while antioxidants help preserve the integrity of cells and some are natural antibiotics. The first conclusion may, however, depend on factors not directly connected to organic farming, such as harvesting and storage methods and the type of land used for growing the food. About the second finding it must be considered that measuring organoleptic quality is difficult and inherently subjective and evaluations may be clouded by the influence of numerous factors on the consumer’s perceptions of the food and not just its appearance and taste. Experimental research indicates that the information that a food is organic confers upon it a “halo effect” (making it seem better sense-wise simply because it is organic) which might make consumers like it more. Ecropolis researchers will analyze in detail which senses are indeed impacted on, and how, and try to match them to consumer needs and expectations in order to be able to offer suggestions for future policy, including how the food is stored, transported and presented, which is also essential for maintaining sensory properties. The workpackage WP1 has also produced a specific report on how organic food sensory aspects are regulated. International standards, with some important exceptions, are largely in line with European ones. Differences in standards usually regard whether there is orientation towards freshness “per se” as opposed to increasing shelf-life, or quality standardization as opposed to quality differentiation. Differences in regulations regard such aspects as ingredients, additives, processing aids and methods, packaging, storage and transport. The lack of harmony among the different regulatory systems often reflects different traditions and market conditions, however, more complicated compliance procedures result in higher costs for importers. Greater homogeneity would not only reduce such costs but would also increase consumer confidence in international standards. Ecropolis will also investigate the effect of different regulations on how people perceive organic goods sense-wise. The work done to date is seen as a starting point for future research aimed at producing practical results in the organic food market. Ecropolis will try to bring together separate strands of research concerning how organic goods are regulated and marketed with regard to taste, appearance, etc., and how consumers themselves are affected by such factors. The aim is to find optimal matches between the two, and thus to greatly increase organic food’s share of the food market

    Pilot interaction with automated airborne decision making systems

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    Two project areas were pursued: the intelligent cockpit and human problem solving. The first area involves an investigation of the use of advanced software engineering methods to aid aircraft crews in procedure selection and execution. The second area is focused on human problem solving in dynamic environments, particulary in terms of identification of rule-based models land alternative approaches to training and aiding. Progress in each area is discussed

    A Survey on IT-Techniques for a Dynamic Emergency Management in Large Infrastructures

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    This deliverable is a survey on the IT techniques that are relevant to the three use cases of the project EMILI. It describes the state-of-the-art in four complementary IT areas: Data cleansing, supervisory control and data acquisition, wireless sensor networks and complex event processing. Even though the deliverable’s authors have tried to avoid a too technical language and have tried to explain every concept referred to, the deliverable might seem rather technical to readers so far little familiar with the techniques it describes
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