47,178 research outputs found

    Machines must be wrong

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    Making mistakes is an intrinsic human feature. But far to be an unwelcome feature, it is useful. For instance it bears us to learn, to review our beliefs and to support our decisions among others. This capability of using mistakes in our reasonings is already represented by Logic by means of the inference rule of “reduction ad absurdum”, which can be seen as a “supervised kind of mistake”. However in Computer Sciences, apart from the theoretical tools of “reductio ad absurdum” and methods obtained from it (as SLD resolution [1]), contradictions and mistakes are considered features that must be avoided. In some situations this behavior is understandable (e.g. the control of a train or a medical device) but in others, it represents a considerable limitation (e.g. in learning or optimization). Thus, considering knowledge systems involved in wrong information is not only an option for the scientific community, but a necessity. In this talk we explain how wrongness can be represented as a fuzzy notion and why con- tradictory information must be considered as an important piece of information nowadays. Moreover, the consideration of inconsistent knowledge systems is motivated to show how we can retrieve informations from wrongness. We refer to readers interested in more information to [2, 3].Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    FDTD Calculations of the Diffraction Coefficient of Vibrating Wedges

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    The full-vector Maxwell\u27s equations Unite-difference time-domain (FDTD) method is employed to calculate diffraction coefficients of vibrating conducting and dielectric wedges. Two-dimensional FDTD models of right-angle wedges are constructed to include total-field scattered-field incident plane-wave source conditions as well as convolutional perfectly matched-layer boundary conditions. These models are first validated by calculating the diffraction coefficient of a stationary perfect electrical conducting (PEC) right-angle wedge for comparison to uniform geometrical theory of diffraction (UTD) analytical solutions. Next, a brute-force FDTD technique for modeling wedge vibrations is utilized to calculate the Doppler diffraction coefficients of vibrating lossless and loss

    Variance changes detection in multivariate time series

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    This paper studies the detection of step changes in the variances and in the correlation structure of the components of a vector of time series. Two procedures are considered. The first is based on the likelihood ratio test and the second on cusum statistics. These two procedures are compared in a simulation study and we conclude that the cusum procedure is more powerful. The procedures are illustrated in two examples.

    La movilización como comunicación: Una contribución latinoamericana al estudio de los movimientos sociales

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    Many scholars have noted the lack of interdisciplinary dialogue and research between the areas of social movements studies and that of media and communications. While social movement studies fail to fully analyse media practices and communicative processes in relation to mobilization, in media and communication the social and political aspects of mobilization are seldom taken into account when analysing communication in social movements. This apparent lack of dialogue is presented in the paper as a consequence of north-centred theorization in the fields of social movement studies and media and communication, which is addressed by spelling out the contribution of Latin American communication scholarship and a view of mobilization as anchored in communication.Muchos académicos han observado la ausencia de diálogo interdisciplinario entre los estudios de los movimientos sociales y de los medios y la comunicación. Mientras que los estudios de los movimientos sociales no analizan de manera integral las prácticas mediáticas y los procesos comunicacionales en relación con la movilización, los estudios de medios y comunicación raras veces toman en cuenta los aspectos socio-políticos cuando analizan la comunicación en los movimientos sociales. Este artículo plantea esa aparente falta de diálogo como una consecuencia de una teorización eurocéntrica, explica en detalle la contribución de los estudios latinoamericanos de la comunicación, y propone una visión de la movilización centrada en la comunicación

    New Perspectives; New Questions: Where Next for Liberation Theology?

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    Reply to ``Comment on `On the inconsistency of the Bohm-Gadella theory with quantum mechanics'''

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    In this reply, we show that when we apply standard distribution theory to the Lippmann-Schwinger equation, the resulting spaces of test functions would comply with the Hardy axiom only if classic results of Paley and Wiener, of Gelfand and Shilov, and of the theory of ultradistributions were wrong. As well, we point out several differences between the ``standard method'' of constructing rigged Hilbert spaces in quantum mechanics and the method used in Time Asymmetric Quantum Theory.Comment: 13 page
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