980 resultados para Open Journal Systems


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Jani Laatikaisen ja Lena Lönngrenin esitys ARTIVA-seminaarissa Helsingissä 5.2.2014.

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El objeto de este poster es presentar la experiencia de manejamiento de un portal de revistas científicas de acceso abierto, en una universidad pública y que integra los editores científicos, profesores y bibliotecarios. Iniciativas de esta naturaleza tienen importancia estratégica para la consolidación y el fortalecimiento del Movimiento de Acceso Abierto en los países en desarrollo, puesto que ofrecen la oportunidad de se vivir plenamente una cultura de acceso abierto en todas las etapas de certificación del conocimiento. La experiencia de la Universidade de São Paulo, se convierte en relevante, ya que promueve la integración de los diversos actores involucrados en la producción de revistas científicas. El Portal de Revistas da USP (http://www.revistas.usp.br), lanzado en 2008, es una iniciativa del Departamento Técnico do Sistema Integrado de Bibliotecas de USP que tiene el Programa de Apoio às Publicações Científicas Periódicas da USP. Esta iniciativa, basada en los principios del Movimiento de Acceso Abierto, tiene como objetivo promover la visibilidad y la accesibilidad de las revistas científicas publicadas oficialmente por la USP. Considerase que las revistas cumplen con un doble papel, como objeto y también vehículo de comunicación. Con esto las inversiones para calificación de las revistas incluyen recursos informáticos para garantizar la interoperabilidad entre distintos sistemas de información (bases de datos, catálogos, repositorios etc.), sistemas de gestión editorial en línea (para agilizar la tramitación de los manuscritos y la disminución de la publicación); la formación de los equipos (técnicos y bibliotecarios), atribuición de nomes DOI (digital object identifier), software de verificación de plágio. En 2012 se cambió el software de gestión del Portal para Open Journal Systems - OJS por lo cual se reunió por la primera vez, en um mismo dominio web las revistas científicas editadas en USP. De las más de 100 revistas publicadas en el Portal 29 están en DOAJ, 27 en SciELO Brasil, 20 en Scopus, 11 en JCR entre outros. En el Portal hay revistas con distintos perfiles, unas más institucionales y otras de calidad internacional. Algunas revistas más antíguas y consolidadas se utilizan de distintos sistemas de gestión de los manuscriptos y en el Portal es como un espejo para garantizar la presencia en la Universidad. Con tantas y tan distintas publicaciones el OJS se presenta como una promisora herramienta para la gestión del Portal de Revistas. El OJS surge como un sistema para la gestión individual de revistas científicos y con los avances de las tecnologías y principalmente del uso por la comunidad se conviertió en herramienta de gestión de Portal. Para una mejor gestión del Portal se presenta algunas recomendaciones, basadas en la experiencia, y que podrán mejorar el trabajo de gestión del conjunto de las revistas: en la pantalla de creación de revistas se deberá incluir todos los datos del registro oficial en ISSN, sin posibilidad de edición por los editores-gerentes; en el listado general de revistas se podría incluir una indicación de las revistas que están en línea y las que están aún en configuración; clara identificación de las revistas vigentes y no-vigentes, una vinculación mas clara de las revistas que cambiaran su título y que están vigentes; una tabla para selección de fuentes de indización; edición de contenidos ya publicados solamente por el administrador del sistema; gestión centralizada del DOI y de la preservación digital en LOCKSS y un painel con los datos estadísticos (total de revistas, ediciones, estatísticas Counter, autores etc). Además el fortalecimiento y creación de centros de desarrollo de OJS en las Universidades Latinoamericanas podría impulsionar el uso del sistema en su totalidad por los editores de la región.

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Graphical user interfaces (GUIs) are critical components of today's open source software. Given their increased relevance, the correctness and usability of GUIs are becoming essential. This paper describes the latest results in the development of our tool to reverse engineer the GUI layer of interactive computing open source systems. We use static analysis techniques to generate models of the user interface behavior from source code. Models help in graphical user interface inspection by allowing designers to concentrate on its more important aspects. One particular type of model that the tool is able to generate is state machines. The paper shows how graph theory can be useful when applied to these models. A number of metrics and algorithms are used in the analysis of aspects of the user interface's quality. The ultimate goal of the tool is to enable analysis of interactive system through GUIs source code inspection.

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Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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A system is said to be "instantaneous" when for a given constant input an equilibrium output is obtained after a while. In the meantime, the output is changing from its initial value towards the equilibrium one. This is the transient period of the system and transients are important features of open-respirometry systems. During transients, one cannot compute the input amplitude directly from the output. The existing models (e.g., first or second order dynamics) cannot account for many of the features observed in real open-respirometry systems, such as time lag. Also, these models do not explain what should be expected when a system is speeded up or slowed down. The purpose of the present study was to develop a mechanistic approach to the dynamics of open-respirometry systems, employing basic thermodynamic concepts. It is demonstrated that all the main relevant features of the output dynamics are due to and can be adequately explained by a distribution of apparent velocities within the set of molecules travelling along the system. The importance of the rate at which the molecules leave the sensor is explored for the first time. The study approaches the difference in calibrating a system with a continuous input and with a "unit impulse": the former truly reveals the dynamics of the system while the latter represents the first derivative (in time) of the former and, thus, cannot adequately be employed in the apparent time-constant determination. Also, we demonstrate why the apparent order of the output changes with volume or flow.

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The basis set superposition error-free second-order MØller-Plesset perturbation theory of intermolecular interactions was studied. The difficulties of the counterpoise (CP) correction in open-shell systems were also discussed. The calculations were performed by a program which was used for testing the new variants of the theory. It was shown that the CP correction for the diabatic surfaces should be preferred to the adiabatic ones

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In this paper, we present a measure of quantum correlation for a multipartite system, defined as the sum of the correlations for all possible partitions. Our measure can be defined for quantum discord (QD), geometric quantum discord or even for entanglement of formation (EOF). For tripartite pure states, we show that the multipartite measures for the QD and the EOF are equivalent, which allows direct comparison of the distribution and the robustness of these correlations in open quantum systems. We study dissipative dynamics for two distinct families of entanglement: a W state and a GHZ state. We show that, for the W state, the QD is more robust than the entanglement, while for the GHZ state, this is not true. It turns out that the initial genuine multipartite entanglement present in the GHZ state makes the EOF more robust than the QD. © IOP Publishing and Deutsche Physikalische Gesellschaft.

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The basis set superposition error-free second-order MØller-Plesset perturbation theory of intermolecular interactions was studied. The difficulties of the counterpoise (CP) correction in open-shell systems were also discussed. The calculations were performed by a program which was used for testing the new variants of the theory. It was shown that the CP correction for the diabatic surfaces should be preferred to the adiabatic ones

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In this Thesis various aspects of memory effects in the dynamics of open quantum systems are studied. We develop a general theoretical framework for open quantum systems beyond the Markov approximation which allows us to investigate different sources of memory effects and to develop methods for harnessing them in order to realise controllable open quantum systems. In the first part of the Thesis a characterisation of non-Markovian dynamics in terms of information flow is developed and applied to study different sources of memory effects. Namely, we study nonlocal memory effects which arise due to initial correlations between two local environments and further the memory effects induced by initial correlations between the open system and the environment. The last part focuses on describing two all-optical experiment in which through selective preparation of the initial environment states the information flow between the system and the environment can be controlled. In the first experiment the system is driven from the Markovian to the non- Markovian regime and the degree of non-Markovianity is determined. In the second experiment we observe the nonlocal nature of the memory effects and provide a novel method to experimentally quantify frequency correlations in photonic environments via polarisation measurements.

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Poster at the CERN Workshop on Innovations in Scholarly Communication (OAI9), Geneva, June 17-19, 2015.

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Presentation at Nordic Open Access Forum meeting in Stockholm, April 25, 2016

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We are currently at the cusp of a revolution in quantum technology that relies not just on the passive use of quantum effects, but on their active control. At the forefront of this revolution is the implementation of a quantum computer. Encoding information in quantum states as “qubits” allows to use entanglement and quantum superposition to perform calculations that are infeasible on classical computers. The fundamental challenge in the realization of quantum computers is to avoid decoherence – the loss of quantum properties – due to unwanted interaction with the environment. This thesis addresses the problem of implementing entangling two-qubit quantum gates that are robust with respect to both decoherence and classical noise. It covers three aspects: the use of efficient numerical tools for the simulation and optimal control of open and closed quantum systems, the role of advanced optimization functionals in facilitating robustness, and the application of these techniques to two of the leading implementations of quantum computation, trapped atoms and superconducting circuits. After a review of the theoretical and numerical foundations, the central part of the thesis starts with the idea of using ensemble optimization to achieve robustness with respect to both classical fluctuations in the system parameters, and decoherence. For the example of a controlled phasegate implemented with trapped Rydberg atoms, this approach is demonstrated to yield a gate that is at least one order of magnitude more robust than the best known analytic scheme. Moreover this robustness is maintained even for gate durations significantly shorter than those obtained in the analytic scheme. Superconducting circuits are a particularly promising architecture for the implementation of a quantum computer. Their flexibility is demonstrated by performing optimizations for both diagonal and non-diagonal quantum gates. In order to achieve robustness with respect to decoherence, it is essential to implement quantum gates in the shortest possible amount of time. This may be facilitated by using an optimization functional that targets an arbitrary perfect entangler, based on a geometric theory of two-qubit gates. For the example of superconducting qubits, it is shown that this approach leads to significantly shorter gate durations, higher fidelities, and faster convergence than the optimization towards specific two-qubit gates. Performing optimization in Liouville space in order to properly take into account decoherence poses significant numerical challenges, as the dimension scales quadratically compared to Hilbert space. However, it can be shown that for a unitary target, the optimization only requires propagation of at most three states, instead of a full basis of Liouville space. Both for the example of trapped Rydberg atoms, and for superconducting qubits, the successful optimization of quantum gates is demonstrated, at a significantly reduced numerical cost than was previously thought possible. Together, the results of this thesis point towards a comprehensive framework for the optimization of robust quantum gates, paving the way for the future realization of quantum computers.

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Since no physical system can ever be completely isolated from its environment, the study of open quantum systems is pivotal to reliably and accurately control complex quantum systems. In practice, reliability of the control field needs to be confirmed via certification of the target evolution while accuracy requires the derivation of high-fidelity control schemes in the presence of decoherence. In the first part of this thesis an algebraic framework is presented that allows to determine the minimal requirements on the unique characterisation of arbitrary unitary gates in open quantum systems, independent on the particular physical implementation of the employed quantum device. To this end, a set of theorems is devised that can be used to assess whether a given set of input states on a quantum channel is sufficient to judge whether a desired unitary gate is realised. This allows to determine the minimal input for such a task, which proves to be, quite remarkably, independent of system size. These results allow to elucidate the fundamental limits regarding certification and tomography of open quantum systems. The combination of these insights with state-of-the-art Monte Carlo process certification techniques permits a significant improvement of the scaling when certifying arbitrary unitary gates. This improvement is not only restricted to quantum information devices where the basic information carrier is the qubit but it also extends to systems where the fundamental informational entities can be of arbitary dimensionality, the so-called qudits. The second part of this thesis concerns the impact of these findings from the point of view of Optimal Control Theory (OCT). OCT for quantum systems utilises concepts from engineering such as feedback and optimisation to engineer constructive and destructive interferences in order to steer a physical process in a desired direction. It turns out that the aforementioned mathematical findings allow to deduce novel optimisation functionals that significantly reduce not only the required memory for numerical control algorithms but also the total CPU time required to obtain a certain fidelity for the optimised process. The thesis concludes by discussing two problems of fundamental interest in quantum information processing from the point of view of optimal control - the preparation of pure states and the implementation of unitary gates in open quantum systems. For both cases specific physical examples are considered: for the former the vibrational cooling of molecules via optical pumping and for the latter a superconducting phase qudit implementation. In particular, it is illustrated how features of the environment can be exploited to reach the desired targets.

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Monográfico con el título: 'Nuevos desafíos en la formación del profesorado'