12,904 research outputs found

    Independence numbers of some double vertex graphs and pair graphs

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    The combinatorial properties of double vertex graphs has been widely studied since the 90's. However only very few results are know about the independence number of such graphs. In this paper we obtain the independence numbers of the double vertex graphs of fan graphs and wheel graphs. Also we obtain the independence numbers of the pair graphs, that is a generalization of the double vertex graphs, of some families of graphs.Comment: 17 pages. Minor changes in the proof

    In perfect future. The End of Time in Augustine, the apocalyptic and Gnostic

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    La reflexiĂłn de AgustĂ­n sobre el tiempo, desde el plano de la salvaciĂłn individual como de la trascendencia de la ciudad divina ubicada desde un principio en la Tierra, logra caracterizar o dar forma a la cultura medieval; sin embargo, tambiĂ©n es evidente que las expectativas que generaron las posiciones de los apocalĂ­pticos – mĂĄs conocidos como milenaristas o quiliastas – y los gnĂłsticos no dejaron de pesar fuertemente dentro del imaginario colectivo que atravesĂł el final del Imperio romano y su continuaciĂłn en el llamado Medioevo. De modo que el contraste entre las nociones sobre el futuro concebidas en estas tres direcciones, permite hacer comprensible en toda su extensiĂłn el sentido y significado de lo que la elecciĂłn del tiempo lineal y finito, oculto bajo nociones mĂ­ticas como RevelaciĂłn, Juicio Final, Reino de Dios, SalvaciĂłn Eterna, representa en el fondo de las creencias que han dado – y de algĂșn modo siguen insuflando – vida a la cultura occidental.Augustine's reflection on time, from the level of individual salvation and the transcendence of the heavenly city located from the beginning on Earth, able to characterize or shape of medieval culture, but it is also clear that the expectations generated apocalyptic positions – better known as millenarian sects – and the Gnostics did not fail to weigh heavily in the collective imagination that went through the end of the Roman Empire and the so-called Middle Ages. So the contrast between conceived notions about the future in these three directions, it allows you to understand the full extent the meaning and significance of the choice of linear and finite time, hidden under mythical notions as Revelation, Last Judgment, Kingdom of God, eternal salvation, is at the bottom of the beliefs that have been – and somehow still blowing – life to Western culture

    Computing Partial Recursive Functions by Virus Machines

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    Virus Machines are a computational paradigm inspired by the manner in which viruses replicate and transmit from one host cell to another. This paradigm provides non-deterministic sequential devices. Non-restricted Virus Machines are unbounded Virus Machines, in the sense that no restriction on the number of hosts, the number of instructions and the number of viruses contained in any host along any computation is placed on them. The computational completeness of these machines has been obtained by simulating register machines. In this paper, Virus Machines as function computing devices are considered. Then, the universality of non-restricted virus machines is proved by showing that they can compute all partial recursive functions.Ministerio de EconomĂ­a y Competitividad TIN2012- 3743

    How to automate a kinematic mount using a 3D printed Arduino-based system

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    We demonstrate a simple, flexible and cost-effective system to automatize most of the kinematic mounts available nowadays on the market. It combines 3D printed components, an Arduino board, stepper motors, and simple electronics. The system developed can control independently and simultaneously up to ten stepper motors using commands sent through the serial port, and it is suitable for applications where optical realignment using flat mirrors is required on a periodic basis.Comment: 9 pages, 8 figure

    Output subsidies and quotas under uncertainty and firm heterogeneity

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    This paper studies the relative efficiency of two kinds of regulations, quantity restrictions (quotas) and output subsidies, in an imperfectly competitive market under the existence of two sources of uncertainty: uncertainty in both costs and prices. We find that when the two sources of uncertainty are independently distributed, the output subsidy instrument has comparative advantage over the quantity instrument. However, when we take into account the possibility of correlation between the random components and across firms marginal costs, we find that a positive (negative) correlation tends to favor the quantity (subsidy) instrument. Finally, we show that when the correlation is positive, it is possible to find situations in which the quantity instrument has comparative advantage over the subsidy instrument.Cost uncertainty, demand uncertainty, firm heterogeneity, output subsidy and quantity instruments

    "Debating as a classroom tool for adapting learning outcomes to the European higher education area"

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    The creation of the European Higher Education Area has meant a number of significant changes to the educational structures of the university community. In particular, the new system of European credits has generated the need for innovation in the design of curricula and teaching methods. In this paper, we propose debating as a classroom tool that can help fulfill these objectives by promoting an active student role in learning. To demonstrate the potential of this tool, a classroom experiment was conducted in a bachelor’s degree course in Industrial Economics (Regulation and Competition), involving a case study in competition policy and incorporating the techniques of a conventional debate (presentation of standpoints, turns, right to reply and summing up). The experiment yielded gains in student attainment and positive assessments of the subject. In conclusion, the incorporation of debating activities helps students to acquire the skills, be they general or specific, required to graduate successfully in Economics.European Higher Education Area; Debating; Industrial Organization; Academic Success; European Credit Transfer System. JEL classification:A23, B4, I2.

    Price rivalry in airline markets: a study of a successful strategy of a network carrier against a low-cost carrier

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    Competition in airline markets may be tough. In this context, network carriers have two alternative strategies to compete with low-cost carriers. First, they may establish a low-cost subsidiary. Second, they may try to reduce costs using the main brand. This paper examines a successful strategy of the first type implemented by Iberia in the Spanish domestic market. Our analysis of data and the estimation of a pricing equation show that Iberia has been able to charge lower prices than rivals with its low-cost subsidiary. The pricing policy of the Spanish network carrier has been particularly aggressive in less dense routes and shorter routes.Airlines, competition, low-cost carriers JEL classification:L13, L59, L71

    EvaluaciĂłn del rendimiento del servicio de videostreaming adaptativo en redes inalĂĄmbricas

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    YouTube Live is one of the most popular services on the Internet, enabling an easy streaming of a live video with acceptable video quality. Thus, understanding userÂŽs perception of this service is of the utmost importance for network operators. The image Quality delivered and user videoplayback behavior on YouTube Live streaming are important keys to ensure an adequate Quality of Experience (QoE). In this paper, an analytical model, and stacked Bar Graph to estimate the QoE for encrypted YouTube Live service from packet-level data collected in the interfaces of a wireless network is presented. The inputs to the model are Transport Control Protocol (TCP)/Internet Protocol (IP) metrics, from which two Service Key Performance Indicators (S-KPIs) are estimated, namely video quality level (itag) and, videoplayback connection ratio. The model is developed with an experimental platform, consisting of a user terminal agent, a WiFi wireless network, a network-level emulator, a Mitmproxy and a probe software. Model assessment is carried out by comparing S-KPI estimates with measurements from the terminal agent under different network conditions introduced by the network emulator.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech. Ministerio de EconomĂ­a y Competitividad (Proyecto TEC2015-69982-R, UNMA13-1E-1864), y FEDER
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