17,183 research outputs found

    Why "consciousness" means what it does.

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    “Consciousness” seems to be a polysemic, ambiguous, term. Because of this, theorists have sought to distinguish the different kinds of phenomena that “consciousness” denotes, leading to a proliferation of terms for different kinds of consciousness. However, some philosophers—univocalists about consciousness—argue that “consciousness” is not polysemic or ambiguous. By drawing upon the history of philosophy and psychology, and some resources from semantic theory, univocalism about consciousness is shown to be implausible. This finding is important, for if we accept the univocalist account then we are less likely to subject our thought and talk about the mind to the kind of critical analysis that it needs. The exploration of the semantics of “consciousness” offered here, by way of contrast, clarifies and fine-tunes our thought and talk about consciousness and conscious mentality and explains why “consciousness” means what it does, and why it means a number of different, but related, things

    Periodic homogenization with an interface

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    We consider a diffusion process with coefficients that are periodic outside of an 'interface region' of finite thickness. The question investigated in the articles [1,2] is the limiting long time / large scale behaviour of such a process under diffusive rescaling. It is clear that outside of the interface, the limiting process must behave like Brownian motion, with diffusion matrices given by the standard theory of homogenization. The interesting behaviour therefore occurs on the interface. Our main result is that the limiting process is a semimartingale whose bounded variation part is proportional to the local time spent on the interface. We also exhibit an explicit way of identifying its parameters in terms of the coefficients of the original diffusion. Our method of proof relies on the framework provided by Freidlin and Wentzell for diffusion processes on a graph in order to identify the generator of the limiting process.Comment: ISAAC 09 conference proceeding

    Evaluation of Intelligent Intrusion Detection Models

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    This paper discusses an evaluation methodology that can be used to assess the performance of intelligent techniques at detecting, as well as predicting, unauthorised activities in networks. The effectiveness and the performance of any developed intrusion detection model will be determined by means of evaluation and validation. The evaluation and the learning prediction performance for this task will be discussed, together with a description of validation procedures. The performance of developed detection models that incorporate intelligent elements can be evaluated using well known standard methods, such as matrix confusion, ROC curves and Lift charts. In this paper these methods, as well as other useful evaluation approaches, are discussed.Peer reviewe

    Modifications to the Theory of the Differential Absorption Experiment

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    Use of Fresnel reflection coefficient for studying reflections from mesospher

    Metal cooldown, flow instability, and heat transfer in two-phase hydrogen flow

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    Studies of the properties of five metals with varying tube-wall thickness, with or without and internal coating of trifluorochloroethylene polymer, show that wall characteristics influence flow stability, affect heat transfer coefficients, and influence the transition point from dry- to wet-wall flow

    Fuzzy stability analysis of regenerative chatter in milling

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    During machining, unstable self-excited vibrations known as regenerative chatter can occur, causing excessive tool wear or failure, and a poor surface finish on the machined workpiece. Consequently it is desirable to predict, and hence avoid the onset of this instability. Regenerative chatter is a function of empirical cutting coefficients, and the structural dynamics of the machine-tool system. There can be significant uncertainties in the underlying parameters, so the predicted stability limits do not necessarily agree with those found in practice. In the present study, fuzzy arithmetic techniques are applied to the chatter stability problem. It is first shown that techniques based upon interval arithmetic are not suitable for this problem due to the issue of recursiveness. An implementation of fuzzy arithmetic is then developed based upon the work of Hanss and Klimke. The arithmetic is then applied to two techniques for predicting milling chatter stability: the classical approach of Altintas, and the time-finite element method of Mann. It is shown that for some cases careful programming can reduce the computational effort to acceptable levels. The problem of milling chatter uncertainty is then considered within the framework of Ben-Haim's information-gap theory. It is shown that the presented approach can be used to solve process design problems with robustness to the uncertain parameters. The fuzzy stability bounds are then compared to previously published data, to investigate how uncertainty propagation techniques can offer more insight into the accuracy of chatter predictions
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