112,255 research outputs found

    The physics and metaphysics of primitive stuff

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    The paper sets out a primitive ontology of the natural world in terms of primitive stuff, that is, stuff that has as such no physical properties at all, but that is not a bare substratum either, being individuated by metrical relations. We focus on quantum physics and employ identity-based Bohmian mechanics to illustrate this view, but point out that it applies all over physics. Properties then enter into the picture exclusively through the role that they play for the dynamics of the primitive stuff. We show that such properties can be local (classical mechanics), as well as holistic (quantum mechanics), and discuss two metaphysical options to conceive them, namely Humeanism and modal realism in the guise of dispositionalism

    Symbolic modeling of structural relationships in the Foundational Model of Anatomy

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    The need for a sharable resource that can provide deep anatomical knowledge and support inference for biomedical applications has recently been the driving force in the creation of biomedical ontologies. Previous attempts at the symbolic representation of anatomical relationships necessary for such ontologies have been largely limited to general partonomy and class subsumption. We propose an ontology of anatomical relationships beyond class assignments and generic part-whole relations and illustrate the inheritance of structural attributes in the Digital Anatomist Foundational Model of Anatomy. Our purpose is to generate a symbolic model that accommodates all structural relationships and physical properties required to comprehensively and explicitly describe the physical organization of the human body

    Modeling urban evolution by identifying spatiotemporal patterns and applying methods of artificial intelligence.Case study: Athens, Greece.

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    While during the past decades, urban areas experience constant slow population growth, the spatial patterns they form, by means of their limits and borders, are rapidly changing in a complex way. Furthermore, urban areas continue to expand to the expense of "rural” intensifying urban sprawl. The main aim of this paper is the definition of the evolution of urban areas and more specifically, the specification of an urban model, which deals simultaneously with the modification of population and building use patterns. Classical theories define city geographic border, with the Aristotelian division of 0 or 1 and are called fiat geographic boundaries. But the edge of a city and the urbanization "degree" is something not easily distinguishable. Actually, the line that city ends and rural starts is vague. In this respect a synthetic spatio - temporal methodology is described which, through the adaptation of different computational methods aims to assist planners and decision makers to gain an insight in urban - rural transition. Fuzzy Logic and Neural Networks are recruited to provide a precise image of spatial entities, further exploited in a twofold way. First for analysis and interpretation of up - to - date urban evolution and second, for the formulation of a robust spatial simulation model, the theoretical background of which is that the spatial contiguity between members of the same or different groups is one of the key factors in their evolution. The paper finally presents the results of the model application in the prefecture of Attica in Greece, unveiling the role of the Athens Metropolitan Area to its current and future evolution, by illustrating maps of urban growth dynamics.urban growth; urban dynamics; neural networks; fuzzy logic; Greece; Athens

    Simulation of urban system evolution in a synergetic modelling framework. The case of Attica, Greece

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    Spatial analysis and evolution simulation of such complex and dynamic systems as modern urban areas could greatly benefit from the synergy of methods and techniques that constitute the core of the fields of Information Technology and Artificial Intelligence. Additionally, if during the decision making process, a consistent methodology is applied and assisted by a user-friendly interface, premium and pragmatic solution strategies can be tested and evaluated. In such a framework, this paper presents both a prototype Decision Support System and a consorting spatio-temporal methodology, for modelling urban growth. Its main focus is on the analysis of current trends, the detection of the factors that mostly affect the evolution process and the examination of user-defined hypotheses regarding future states of the problem environment. According to the approach, a neural network model is formulated for a specific time intervals and each different group of spatial units, mainly based to the degree of their contiguity and spatial interaction. At this stage, fuzzy logic provides a precise image of spatial entities, further exploited in a twofold way. First, for the analysis and interpretation of up-to-date urban evolution and second, for the formulation of a robust spatial simulation model. It should be stressed, however, that the neural network model is not solely used to define future urban images, but also to evaluate the degree of influence that each variable as a significant of problem parameter, contributes to the final result. Thus, the formulation and the analysis of alternative planning scenarios are assisted. Both the proposed methodological framework and the prototype Decision Support System are utilized during the study of Attica, Greece?s principal prefecture and the definition of a twenty-year forecast. The variables considered and projected refer to population data derived from the 1961-1991 censuses and building uses aggregated in ten different categories. The final results are visualised through thematic maps in a GIS environment. Finally, the performance of the methodology is evaluated as well as directions for further improvements and enhancements are outlined. Keywords: Computational geography, Spatial modelling, Neural network models, Fuzzy logic.

    Are Dark Energy and Dark Matter Different Aspects of the Same Physical Process?

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    It is suggested that the apparently disparate cosmological phenomena attributed to so-called 'dark matter' and 'dark energy' arise from the same fundamental physical process: the emergence, from the quantum level, of spacetime itself. This creation of spacetime results in metric expansion around mass points in addition to the usual curvature due to stress-energy sources of the gravitational field. A recent modification of Einstein's theory of general relativity by Chadwick, Hodgkinson, and McDonald incorporating spacetime expansion around mass points, which accounts well for the observed galactic rotation curves, is adduced in support of the proposal. Recent observational evidence corroborates a prediction of the model that the apparent amount of 'dark matter' increases with the age of the universe. In addition, the proposal leads to the same result for the small but nonvanishing cosmological constant, related to 'dark energy, as that of the causet model of Sorkin et al.Comment: Some typos corrected. Comments welcome, pro or co

    Event-driven grammars: Relating abstract and concrete levels of visual languages

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s10270-007-0051-2In this work we introduce event-driven grammars, a kind of graph grammars that are especially suited for visual modelling environments generated by meta-modelling. Rules in these grammars may be triggered by user actions (such as creating, editing or connecting elements) and in their turn may trigger other user-interface events. Their combination with triple graph transformation systems allows constructing and checking the consistency of the abstract syntax graph while the user is building the concrete syntax model, as well as managing the layout of the concrete syntax representation. As an example of these concepts, we show the definition of a modelling environment for UML sequence diagrams. A discussion is also presented of methodological aspects for the generation of environments for visual languages with multiple views, its connection with triple graph grammars, the formalization of the latter in the double pushout approach and its extension with an inheritance concept.This work has been partially sponsored by the Spanish Ministry of Education and Science with projects MOSAIC (TSI2005-08225-C07-06) and MODUWEB (TIN 2006-09678)

    The lingua franca of Nominalism. Sellars on Leibniz

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    The paper is not built upon a single central thesis. It has been composed as an attempt to investigate a virtually unexplored theme of inquiry. A kind of historiographical thesis may be put in the following terms: Leibniz can be counted among the remote, but still significant, sources of Sellars's philosophy. Such thesis, however, is meaningless unless its conceptual relevance is displayed. Therefore, it will be immediately added that Sellars's relation with Leibniz is focused on three main fundamental issues, which respectively concern (1) the concept of nature, (2) the concept of truth and (3) the concept itself of nominalism. Besides, there are other seemingly minor topics, which actually refers to the definition of abstract entities, of predicates, of proper names and to the datum/factum distinction. Another challenge the paper is faced with, regards the fact that Sellars does not consider Leibniz only in himself, given that he very often positions him in a close relation to Kant: it is as though there were multifaceted issues brought forward by Leibniz and Kant together forming a complex theoretical unity (over and above their differences). According to Sellars, in fact, they both undermine some of the most solid epistemological principles of the early modern times (mainly founded upon the subject- object lexicon and the idea of veritas as adaequatio rei et intellectus) and they both reshape the meaning of expressions such as \u201cbeing actual\u201d or \u201cbeing true\u201d

    The nonclassical mereology of olfactory experiences

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    While there is a growing philosophical interest in analysing olfactory experiences, the mereological structure of odours considered in respect of how they are perceptually experienced has not yet been extensively investigated. The paper argues that odours are perceptually experienced as having a mereological structure, but this structure is significantly different from the spatial mereological structure of visually experienced objects. Most importantly, in the case of the olfactory part-structure, the classical weak supplementation principle is not satisfied. This thesis is justified by referring to empirical results in olfactory science concerning the human ability to identify components in complex olfactory stimuli. Further, it is shown how differences between olfactory and visual mereologies may arise from the way in which these modalities represent space

    The emotional contents of the ‘space’ in spatial music

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    Human spatial perception is how we understand places. Beyond understanding what is where (William James’ formulation of the psychological approach to perception); there are holistic qualities to places. We perceive places as busy, crowded, exciting, threatening or peaceful, calm, comfortable and so on. Designers of places spend a great deal of time and effort on these qualities; scientists rarely do. In the scientific world-view physical qualities and our emotive responses to them are neatly divided in the objective-subjective dichotomy. In this context, music has traditionally constituted an item in a place. Over the last two decades, development of “spatial music” has been within the prevailing engineering paradigm, informed by psychophysical data; here, space is an abstract, Euclidean 3-dimensional ‘container’ for events. The emotional consequence of spatial arrangements is not the main focus in this approach. This paper argues that a paradigm shift is appropriate, from ‘music-in-a-place’ to ‘music-as-a-place’ requiring a fundamental philosophical realignment of ‘meaning’ away from subjective response to include consequences-in-the-environment. Hence the hegemony of the subjective-objective dichotomy is questioned. There are precedents for this, for example in the ecological approach to perception (Gibson). An ecological approach to music-as-environment intrinsically treats the emotional consequences of spatio-musical arrangement holistically. A simplified taxonomy of the attributes of artificial spatial sound in this context will be discussed
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