7,087 research outputs found

    A Conversão da Consciência como princípio da moralidade

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    Kant mostra que uma teoria fundamental da normatividade e da moralidade não pode dar nem uma explanação nem uma prova da normatividade, mas apenas pode articular e explicitar sua origem. Ela pode fazer isso indicando o lugar ou o topos e a virada ou a trope de seu originar. Conforme Kant, o topos da normatividade é a vontade enquanto razão prática e sua trope é o uso geral desta razão que tipicamente é instrumental, no sentido da reflexão. A trope da origem da moralidade é a autonomia, i.e., a virada da razão prática sobre si mesma, tornando-se pura neste ato. Nisso, a razão prática estabelece sua própria forma como lei para si mesma, na forma do imperativo categórico. Em consequência disso, a ética fundamental serve duas funções : formalmente, ela fornece evidência da originalidade e autenticidade da moralidade; materialmente, ela fornece um princípio criteriológico para o conteúdo da moralidade. O artigo argumenta que Kant estava certo em sua visão da fundamentação da ética, mas estava errado com relação à maneira como ele tentou cumprir as exigências estabelecidas. O topos da normatividade e, em consequência disso, da moralidade, não pode ser a razão, mas precisa ser a consciência ou, mais exatamente, o saber de se ; e sua trope fundamental não pode ser reflexão e, depois, autonomia, mas precisa ser o que pode ser descrito como conversão da consciência. Essa conversão pode ser identificada com o philein no sentido de Aristóteles. Este “amar amigável” tem quatro aspectos diferentes: desejo, cognição, benevolência e reconhecimento. Quando este philein for recíproco e estiver continuamente vivido, nasce a philia, a amizade. Essa é descrita, consequentemente, como o topos da origem de normatividade e moralidade

    Bounding Stochastic Dependence, Complete Mixability of Matrices, and Multidimensional Bottleneck Assignment Problems

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    We call a matrix completely mixable if the entries in its columns can be permuted so that all row sums are equal. If it is not completely mixable, we want to determine the smallest maximal and largest minimal row sum attainable. These values provide a discrete approximation of of minimum variance problems for discrete distributions, a problem motivated by the question how to estimate the α\alpha-quantile of an aggregate random variable with unknown dependence structure given the marginals of the constituent random variables. We relate this problem to the multidimensional bottleneck assignment problem and show that there exists a polynomial 22-approximation algorithm if the matrix has only 33 columns. In general, deciding complete mixability is NP\mathcal{NP}-complete. In particular the swapping algorithm of Puccetti et al. is not an exact method unless NPZPP\mathcal{NP}\subseteq\mathcal{ZPP}. For a fixed number of columns it remains NP\mathcal{NP}-complete, but there exists a PTAS. The problem can be solved in pseudopolynomial time for a fixed number of rows, and even in polynomial time if all columns furthermore contain entries from the same multiset

    An Implementation of Distance-Based Message Authentication for WSNs

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    Distance-Based Message Authentication (DBMA) provides an additional layer of access control and helps to defend against key compromise and denial-of-service attacks on constrained nodes. The distance between sender and receiver is measured securely. Messages sent from outside a defined physical distance can be rejected early, protecting vulnerable higher layers. We show our initial implementation using the Nanotron NA5TR1. We show how changing MAC addresses can avoid modification to ranging hardware

    The Wild Huntsman (A Message for the Semi-Educated Classes)

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    Utz Rachowski was Writer in Residence in the Department of German Studies in spring 2012. This story of youth, family, and homeland was originally published in German in 2006

    Kreuzberg/Calvary

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    Utz Rachowski\u27s poem Kreuzberg, first published in 1995, appears here in English translation surrounded by the work of much younger talents

    On artifact solutions of semi-analytic methods in nonlinear dynamics

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    Nonlinear dynamics is a topic of permanent interest in mechanics since decades. The authors have recently published some results on a very classical topic, the dynamics of a softening Duffing oscillator under harmonic excitation focusing especially on low-frequency excitation (von Wagner in Arch Appl Mech 86(8):1383–1390, 2016). In this paper, it was shown that classical tools like harmonic balance and perturbation analysis may produce artificial solutions when applied without extra carefulness with respect to parameter ranges in the case of perturbation analysis or prior knowledge about the type of solution in case of harmonic balance. In the present paper these results are shortly summarized as they give the starting point for the additional investigations described herein. First, the method of slowly changing phase and amplitude is reviewed with respect to its capability of determining asymptotic stability of stationary solutions. It is shown that this method can also produce artifact results when applied without extra carefulness. As next example an extended Duffing oscillator is investigated, which shows, if harmonic balance is applied, “islands” of solutions. Using the error criterion in harmonic balance as described in von Wagner (2016) again artifact solutions can be identified

    On Artifacts in Nonlinear Dynamics

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    Nonlinear oscillations are of permanent interest in the field of dynamics of mechanical and mechatronical systems. There exist several well-known semi-analytical methods like Harmonic Balance, perturbation analysis or multiple scales for such problems. We reconsider in our presentation the method of Harmonic Balance but add some additional steps in order to avoid artifacts and get information about the stability. The classical method of Harmonic Balance is therefore added by an error criterion, which considers the neglected terms. Looking on this error for increasing ansatz orders, it can be decided whether a solution exists or is an artifact of the method. For the low error solutions, a stability analysis is performed. As example, an extended Duffing oscillator with additional nonlinear damping and excitation is considered showing regions of separated island solutions. Also a nonlinear piezo-beam energy harvesting system is investigated. The described method enables to calculate solutions in a rapid manner with comparable low effort, to get an overview over regular responses of nonlinear systems.DFG, 253161314, Untersuchung des nichtlinearen dynamischen Verhaltens von stochastisch erregten Energy Harvesting Systemen mittels Lösung der Fokker-Planck-Gleichun

    Optimized usage of network resources based on context information

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    Today an efficient (cost-effective) design and usage of networks is of particular importance. As more and more computer systems become context-aware the question of how context information can be used to improve computer networks arises. In this poster we describe how context information can be used to optimize the usage of resources in a computer network. By means of a mobile payment system we show how these optimization method can be applied

    On some aspects of the dynamic behavior of the softening Duffing oscillator under harmonic excitation

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    The Duffing oscillator is probably the most popular example of a nonlinear oscillator in dynamics. Considering the case of softening Duffing oscillator with weak damping and harmonic excitation and performing standard methods like harmonic balance or perturbation analysis, zero mean solutions with large amplitudes are found for small excitation frequencies. These solutions produce a ”nose-like” curve in the amplitude–frequency diagram and merge with the inclining resonance curve for decreasing (but non-vanishing) damping. These results are presented without any additional discussion in several textbooks. The present paper discusses the accurateness of these solutions by introducing an error estimation in the harmonic balance method showing large errors. Performing a modified perturbation analysis leads to solutions with non-vanishing mean value, showing very small errors in the harmonic balance error analysis

    Evaluating and improving firewalls for ip-telephony environments

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    Firewalls are a well established security mechanism for providing access control and auditing at the borders between different administrative network domains. Their basic architecture, techniques and operation modes did not change fundamentally during the last years. On the other side new challenges emerge rapidly when new innovative application domains have to be supported. IP-Telephony applications are considered to have a huge economic potential in the near future. For their widespread acceptance and thereby their economic success they must cope with established security policies. Existing firewalls face immense problems here, if they - as it still happens quite often - try to handle the new challenges in a way they did with "traditional applications". As we will show in this paper, IP-Telephony applications differ from those in many aspects, which makes such an approach quite inadequate. After identifying and characterizing the problems we therefore describe and evaluate a more appropriate approach. The feasibility of our architecture will be shown. It forms the basis of a prototype implementation, that we are currently working on
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