1,985 research outputs found

    Towards a generalisation of formal concept analysis for data mining purposes

    Get PDF
    In this paper we justify the need for a generalisation of Formal Concept Analysis for the purpose of data mining and begin the synthesis of such theory. For that purpose, we first review semirings and semimodules over semirings as the appropriate objects to use in abstracting the Boolean algebra and the notion of extents and intents, respectively. We later bring to bear powerful theorems developed in the field of linear algebra over idempotent semimodules to try to build a Fundamental Theorem for K-Formal Concept Analysis, where K is a type of idempotent semiring. Finally, we try to put Formal Concept Analysis in new perspective by considering it as a concrete instance of the theory developed

    Traceability for Food Safety and Quality Assurance: Mandatory Systems Miss the Mark

    Get PDF
    Traceability systems are record-keeping systems that are primarily used to help keep foods with different attributes separate from one another. When information about a particular attribute of a food product is systematically recorded from creation through marketing, traceability for that attribute is established. Recently, policy makers in many countries have begun weighing the usefulness of mandatory traceability for managing such diverse problems as the threat of bio-terrorism, country-of-origin labelling, mad cow disease, and identification of genetically engineered foods. The question before policymakers is, When is mandatory traceability a useful and appropriate policy choice?Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

    TRACEABILITY IN THE U.S. FOOD SUPPLY: ECONOMIC THEORY AND INDUSTRY STUDIES

    Get PDF
    This investigation into the traceability baseline in the United States finds that private sector food firms have developed a substantial capacity to trace. Traceability systems are a tool to help firms manage the flow of inputs and products to improve efficiency, product differentiation, food safety, and product quality. Firms balance the private costs and benefits of traceability to determine the efficient level of traceability. In cases of market failure, where the private sector supply of traceability is not socially optimal, the private sector has developed a number of mechanisms to correct the problem, including contracting, third-party safety/quality audits, and industry-maintained standards. The best-targeted government policies for strengthening firms' incentives to invest in traceability are aimed at ensuring that unsafe of falsely advertised foods are quickly removed from the system, while allowing firms the flexibility to determine the manner. Possible policy tools include timed recall standards, increased penalties for distribution of unsafe foods, and increased foodborne-illness surveillance.traceability, tracking, traceback, tracing, recall, supply-side management, food safety, product differentiation, Food Consumption/Nutrition/Food Safety, Industrial Organization,

    Characterizing rings in terms of the extent of injectivity and projectivity of their modules

    Get PDF
    Given a ring R, we define its right i-profile (resp. right p-profile) to be the collection of injectivity domains (resp. projectivity domains) of its right R-modules. We study the lattice theoretic properties of these profiles and consider ways in which properties of the profiles may determine the structure of rings and viceversa. We show that the i-profile is isomorphic to an interval of the lattice of linear filters of right ideals of R, and is therefore modular and coatomic. In particular, we give a practical characterization of the i-profile of a right artinian ring. We show through an example that the p-profile is not necessarily a set, and also characterize the right p-profile of a right perfect ring. The study of rings in terms of their (i- or p-)profile was inspired by the study of rings with no (i- or p-) middle class, initiated in recent papers by Er, L\'opez-Permouth and S\"okmez, and by Holston, L\'opez-Permouth and Orhan-Ertas. In this paper, we obtain further results about these rings and we also use our results to provide a characterization of a special class of QF-rings in which the injectivity and projectivity domains of any module coincide.Comment: 19 pages, examples and propositions added. Title change

    Magnetic-film atom chip with 10 ÎĽ\mum period lattices of microtraps for quantum information science with Rydberg atoms

    Get PDF
    We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 ÎĽ\mum, suitable for experiments in quantum information science employing the interaction between atoms in highly-excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cut out of a silver foil, was mounted under the atom chip in order to load ultracold 87^{87}Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.Comment: 7 pages, 7 figure

    Elevated physiological arousal is associated with larger but more variable neural responses to small acoustic change in children during a passive auditory attention task

    Get PDF
    Little is known of how autonomic arousal relates to neural responsiveness during auditory attention. We presented N = 21 5-7-year-old children with an oddball auditory mismatch paradigm, whilst concurrently measuring heart rate fluctuations. Children with higher mean autonomic arousal, as indexed by higher heart rate (HR) and decreased high-frequency (0.15-0.8 Hz) variability in HR, showed smaller amplitude N250 responses to frequently presented (70%), 500 Hz standard tones. Follow-up analyses showed that the modal evoked response was in fact similar, but accompanied by more large and small amplitude responses and greater variability in peak latency in the high HR group, causing lower averaged responses. Similar patterns were also observed when examining heart rate fluctuations within a testing session, in an analysis that controlled for between-participant differences in mean HR. In addition, we observed larger P150/P3a amplitudes in response to small acoustic contrasts (750 Hz tones) in the high HR group. Responses to large acoustic contrasts (bursts of white noise), however, evoked strong early P3a phase in all children and did not differ by high/low HR. Our findings suggest that elevated physiological arousal may be associated with high variability in auditory ERP responses in young children, along with increased responsiveness to small acoustic changes
    • …
    corecore