1,831 research outputs found

    Computerized monitoring and control of experiments in space

    Get PDF
    The computer subsystem of the Villanova University GAS (Get Away Special) experiment apparatus is discussed. The function of the computer subsystem is to provide data acquisition and control system support to the experiments. The computer subsystem will provide high availability, low power consumption and highly reliable data retention. The general layout of the subsystem provides for redundant processing units, control modules, and multiple data acquisition modules. Each of the two redundant processing units will be composed of a microprocessor, control logic, PROM, RAM, non-volitile memory, timers, self-check logic and data ports to the data acquisition and control modules. One unit will control the experiment while the other shadows the primary unit operation. The data acquisition module gathers data from the experiment. The data is transfered to the processing unit in digital form. The control module validates the data, decodes it and executes the command

    Classification with Costly Features using Deep Reinforcement Learning

    Full text link
    We study a classification problem where each feature can be acquired for a cost and the goal is to optimize a trade-off between the expected classification error and the feature cost. We revisit a former approach that has framed the problem as a sequential decision-making problem and solved it by Q-learning with a linear approximation, where individual actions are either requests for feature values or terminate the episode by providing a classification decision. On a set of eight problems, we demonstrate that by replacing the linear approximation with neural networks the approach becomes comparable to the state-of-the-art algorithms developed specifically for this problem. The approach is flexible, as it can be improved with any new reinforcement learning enhancement, it allows inclusion of pre-trained high-performance classifier, and unlike prior art, its performance is robust across all evaluated datasets.Comment: AAAI 201

    The Advocate

    Get PDF
    Birnbaum Wins Keefe Award; Favors Moot Court Board; The Return of the Death Penaltyhttps://ir.lawnet.fordham.edu/student_the_advocate/1057/thumbnail.jp

    Efficient sampling in materials simulation - exploring the parameter space of grain boundaries

    Get PDF
    In the framework of materials design there is the demand for extensive databases of specific materials properties. In this work we suggest an improved strategy for creating future databases, especially for extrinsic properties that depend on several material parameters. As an example we choose the energy of grain boundaries as a function of their geometric degrees of freedom. The construction of existing databases of grain boundary energies in face-centred and body centred cubic metals relied on the a-priori knowledge of the location of important cusps and maxima in the five-dimensional energy landscape, and on an as-densely- as-possible sampling strategy. We introduce two methods to improve the current state of the art. The location and number of the energy minima along which the hierarchical sampling takes place is predicted from existing data points without any a-priori knowledge, using a predictor function. Furthermore we show that it is more efficient to use a sequential sampling in a \design of experiment" scheme, rather than sampling all observations homogeneously in one batch. This sequential design exhibits a smaller error than the simultaneous one, and thus can provide the same accuracy with fewer data points. The new strategy should be particularly beneficial in the exploration of grain boundary energies in new alloys and/or non-cubic structures

    Möglichkeiten und Grenzen der Schätzung der Schattenwirtschaft -- Eine kritische Auseinandersetzung mit den Schätzergebnissen der Bargeldmethode nach Schneider --

    Get PDF
    Official national accounts don't show the extent of the shadow economy. Therefore some estimation work is necessary. The paper classifies its methods. Since Schneider published several results for Germany, the paper centers on the estemating methods of his work. Looking in detail the currency method used by Schneider shows a lot of weaknesses, so the pre-sented volume of shadow economy has to be questioned. Therefore the large number of users of his estimation results have to be informed more intensely.

    Preparation and spectroscopy of a metastable Mott insulator state with attractive interactions

    Full text link
    We prepare and study a metastable attractive Mott insulator state formed with bosonic atoms in a three-dimensional optical lattice. Starting from a Mott insulator with Cs atoms at weak repulsive interactions, we use a magnetic Feshbach resonance to tune the interactions to large attractive values and produce a metastable state pinned by attractive interactions with a lifetime on the order of 10 seconds. We probe the (de-)excitation spectrum via lattice modulation spectroscopy, measuring the interaction dependence of two- and three-body bound state energies. As a result of increased on-site three-body loss we observe resonance broadening and suppression of tunneling processes that produce three-body occupation.Comment: 7 pages, 6 figure

    Do not attempt resuscitation : the importance of consensual decisions

    Get PDF
    Aims: To describe the involvement and input of physicians and nurses in cardiopulmonary resuscitation (cpr / do not attempt resuscitation (dnar) decisions; to analyse decision patterns; and understand the practical implications. Design: A qualitative grounded theory study using one-time open-ended interviews with 40 volunteer physicians and 52 nurses drawn from acute care wards with mixes of heterogeneous cases in seven different hospitals in German-speaking Switzerland. Results: Establishing dnar orders in the best interests of patients was described as a challenging task requiring the leadership of senior physicians and nurses. Implicit decisions in favour of cpr predominated at the beginning of hospitalisation; depending on the context, they were relieved/superseded by explicit dnar decisions. Explicit decisions were the result of hierarchical medical expertise, of multilateral interdisciplinary expertise, of patient autonomy and/or of negotiated patient autonomy. Each type of decision, implicit or explicit, potentially represented a team consensus. Non-consensual decisions were prone to precipitate personal or team conflicts, and, occasionally, led to non-compliance. Conclusion: Establishing dnar orders is a demanding task. Reaching a consensus is of crucial importance in guaranteeing teamwork and good patient care. Communication and negotiation skills, professional and personal life experience and empathy for patients and colleagues are pivotal. Therefore, leadership by experienced senior physicians and nurses is needed and great efforts should be made with regard to multidisciplinary education

    Role of charge carriers for ferromagnetism in cobalt-doped rutile TiO2

    Full text link
    Electric and magnetic properties of a high temperature ferromagnetic oxide semiconductor, cobalt-doped rutile TiO2, are summarized. The cobalt-doped rutile TiO2 epitaxial thin films with different electron densities and cobalt contents were grown on r-sapphire substrates with laser molecular beam epitaxy. Results of magnetization, magnetic circular dichroism, and anomalous Hall effect measurements were examined for samples with systematically varied electron densities and cobalt contents. The samples with high electron densities and cobalt contents show the high temperature ferromagnetism, suggesting that charge carriers induce the ferromagnetism.Comment: 14 pages, 12 figure

    Electrical transport and optical studies of ferromagnetic Cobalt doped ZnO nanoparticles exhibiting a metal-insulator transition

    Full text link
    The observed correlation of oxygen vacancies and room temperature ferromagnetic ordering in Co doped ZnO1-o nanoparticles reported earlier (Naeem et al Nanotechnology 17, 2675-2680) has been further explored by transport and optical measurements. In these particles room temperature ferromagnetic ordering had been observed to occur only after annealing in forming gas. In the current work the optical properties have been studied by diffuse reflection spectroscopy in the UV-Vis region and the band gap of the Co doped compositions has been found to decrease with Co addition. Reflections minima are observed at the energies characteristic of Co+2 d-d (tethrahedral symmetry) crystal field transitions, further establishing the presence of Co in substitutional sites. Electrical transport measurements on palletized samples of the nanoparticles show that the effect of a forming gas is to strongly decrease the resistivity with increasing Co concentration. For the air annealed and non-ferromagnetic samples the variation in the resistivity as a function of Co content are opposite to those observed in the particles prepared in forming gas. The ferromagnetic samples exhibit an apparent change from insulator to metal with increasing temperatures for T>380K and this change becomes more pronounced with increasing Co content. The magnetic and resistive behaviors are correlated by considering the model by Calderon et al [M. J. Calderon and S. D. Sarma, Annals of Physics 2007 (Accepted doi: 10.1016/j.aop.2007.01.010] where the ferromagnetism changes from being mediated by polarons in the low temperature insulating region to being mediated by the carriers released from the weakly bound states in the higher temperature metallic region.Comment: 7 pages, 6 figure
    corecore