298 research outputs found

    Towards a Notion of Distributed Time for Petri Nets

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    We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models

    Gravitational intraction on quantum level and consequences thereof

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    The notion of gravitational emission as an emission of the same level with electromagnetic emission is based on the proven fact of existence of electrons stationary states in its own gravitational field, characterized by gravitational constantComment: 22 pages, 9 figure

    Assessment of suitable observation conditions for a monthly operational remote sensing based crop monitoring system.

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    Abstract: Cloud cover is the main issue to consider when remote sensing images are used to identify, map and monitor croplands, especially over the summer season (October to March in Brazi). This paper aims at evaluating clear sky conditions over four Brazilian states (Sa?o Paulo, Parana?, Santa Catarina, and Rio Grande do Sul) to assess suitable observation conditions for a monthly basis operational crop monitoring system. Cloudiness was analyzed using MODIS Cloud Mask product (MOD35), which presents four labels for cloud cover status: cloudy, uncertainty, probably clear and confident clear. R software was used to compute average values of clear sky with a confidence interval of 95% for each month between July 1st, 2000 and June 30th, 2013. Results showed significant differences within and between the four tested states. Moreover, the period from November to March presented 50% less clear sky areas when compared to April to October

    A Logic with Reverse Modalities for History-preserving Bisimulations

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    We introduce event identifier logic (EIL) which extends Hennessy-Milner logic by the addition of (1) reverse as well as forward modalities, and (2) identifiers to keep track of events. We show that this logic corresponds to hereditary history-preserving (HH) bisimulation equivalence within a particular true-concurrency model, namely stable configuration structures. We furthermore show how natural sublogics of EIL correspond to coarser equivalences. In particular we provide logical characterisations of weak history-preserving (WH) and history-preserving (H) bisimulation. Logics corresponding to HH and H bisimulation have been given previously, but not to WH bisimulation (when autoconcurrency is allowed), as far as we are aware. We also present characteristic formulas which characterise individual structures with respect to history-preserving equivalences.Comment: In Proceedings EXPRESS 2011, arXiv:1108.407

    Blueberry Research Progress Report

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    The 1976 edition of the Blueberry Research Progress Report was prepared for the Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Effect of Plant-Water Stress on Lowbush Blueberry Growth, Yield and Quality 2. Insects Affecting the Blueberry 3. The Development of Blueberry Varieties Adapted to Maine 4. Weed Control in Blueberry Fields 5. Pruning of Blueberries 6. Integrated Management of Blueberry Fields 7. The Physiology and Biochemistry of the Development of the Lowbush Blueberry Fruit 8. Survey of Red Leaf Disease of Blueberries 9. Blossom Blight of Blueberries 10. Blueberry Marketing and Cost Analysis of Producing Blueberries 11. Factors Regulating Rhizome Initiation and Development in the Lowbush Blueberry 12. New Food Products and Servic

    Weak Sequential Composition in Process Algebras

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    n this paper we study a special operator for sequential composition, which is defined relative to a dependency relation over the actions of a given system. The idea is that actions which are not dependent (intuitively because they share no common resources) do not have to wait for one another to proceed, even if they are composed sequentially. Such a notion has been studied before in a linear-time setting, but until recently there has been no systematic investigation in the context of process algebras. We give a structural operational semantics for a process algebraic language containing such a sequential composition operator, which shows some interesting interplay with choice. We give a complete axiomatisation of strong bisimilarity and we show consistency of the operational semantics with an event-based denotational semantics developed recently by the second author. The axiom system allows to derive the communication closed layers law, which in the linear time setting has been shown to be a very useful instrument in correctness preserving transformations. We conclude with a couple of examples

    Blueberry Progress Reports

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    The 1978 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Life Sciences and Agriculture Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include: 1. Weed Control in Blueberry Fields 2. Pruning of Blueberries 3. Integrated Management of Blueberry Fields 4. Factors Regulating Rhizome Initiation and Development in the Lowbush Blueberry 5. Effect of Plant-Water Stress on Lowbush Blueberry Growth Yield and Quality 6. Blossom Blight of Blueberries 7. Botrytis Blossom Blight of Lowbush Blueberries 8. Insects Affecting the Blueberry 9. Treatment of Blueberries with Potassium Sorbate to Reduce Spoilage During Temporary Storage 10. Cooperative Extension Activitie

    Entrepreneurs’ age, institutions, and social value creation goals: a multi-country study

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    This study explores the relationship between an entrepreneur's age and his/her social value creation goals. Building on the lifespan developmental psychology literature and institutional theory, we hypothesize a U-shaped relationship between entrepreneurs’ age and their choice to create social value through their ventures, such that younger and older entrepreneurs create more social value with their businesses while middle age entrepreneurs are relatively more economically and less socially oriented with their ventures. We further hypothesize that the quality of a country’s formal institutions in terms of economic, social, and political freedom steepen the U-shaped relationship between entrepreneurs’ age and their choice to pursue social value creation as supportive institutional environments allow entrepreneurs to follow their age-based preferences. We confirm our predictions using multilevel mixed-effects linear regressions on a sample of over 15,000 entrepreneurs (aged between 18 and 64 years) in 45 countries from Global Entrepreneurship Monitor data. The findings are robust to several alternative specifications. Based on our findings, we discuss implications for theory and practice, and we propose future research directions

    How User‐centric Innovation is Affecting Stakeholder Marketing Strategies: Exploratory Findings from the Music Industry

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    This paper empirically explores how user‐centric innovation (UCI) in the music industry is affecting how key stakeholder groups are approaching and developing their marketing (and associated management) strategies. The three‐stage interview‐based research methodology consisted of 52 semi‐structured in‐depth interviews with UCI experts and artist managers, as well as representatives from major record labels. The findings make four substantial contributions to theory and practice in the interrelated fields of UCI, marketing and the music industry. First, they provide practical and pragmatic insights for industry practitioners on how different UCI marketing approaches are affecting their management strategies. Second, they take steps towards answering many of the identified gaps in research and knowledge relating to the concept of UCI. Third, they present theoretical models as a foundation for which new UCI marketing theory can be built upon. Last, they offer directions for future research to advance our empirical findings.</jats:p
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