2,136 research outputs found

    Analysis and Optimization of Deep Counterfactual Value Networks

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    Recently a strong poker-playing algorithm called DeepStack was published, which is able to find an approximate Nash equilibrium during gameplay by using heuristic values of future states predicted by deep neural networks. This paper analyzes new ways of encoding the inputs and outputs of DeepStack's deep counterfactual value networks based on traditional abstraction techniques, as well as an unabstracted encoding, which was able to increase the network's accuracy.Comment: Long version of publication appearing at KI 2018: The 41st German Conference on Artificial Intelligence (http://dx.doi.org/10.1007/978-3-030-00111-7_26). Corrected typo in titl

    B-52 stability augmentation system reliability

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    The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability

    Methane emissions from western Siberian wetlands: heterogeneity and sensitivity to climate change

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    The prediction of methane emissions from high-latitude wetlands is important given concerns about their sensitivity to a warming climate. As a basis for the prediction of wetland methane emissions at regional scales, we coupled the variable infiltration capacity macroscale hydrological model (VIC) with the biosphere–energy-transfer–hydrology terrestrial ecosystem model (BETHY) and a wetland methane emissions model to make large-scale estimates of methane emissions as a function of soil temperature, water table depth, and net primary productivity (NPP), with a parameterization of the sub-grid heterogeneity of the water table depth based on TOPMODEL. We simulated the methane emissions from a 100 km × 100 km region of western Siberia surrounding the Bakchar Bog, for a retrospective baseline period of 1980–1999 and have evaluated their sensitivity to increases in temperature of 0–5 °C and increases in precipitation of 0–15%. The interactions of temperature and precipitation, through their effects on the water table depth, played an important role in determining methane emissions from these wetlands. The balance between these effects varied spatially, and their net effect depended in part on sub-grid topographic heterogeneity. Higher temperatures alone increased methane production in saturated areas, but caused those saturated areas to shrink in extent, resulting in a net reduction in methane emissions. Higher precipitation alone raised water tables and expanded the saturated area, resulting in a net increase in methane emissions. Combining a temperature increase of 3 °C and an increase of 10% in precipitation to represent climate conditions that may pertain in western Siberia at the end of this century resulted in roughly a doubling in annual emissions

    Agreement between methods of measurement with multiple observations per individual

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    Limits of agreement provide a straightforward and intuitive approach to agreement between different methods for measuring the same quantity. When pairs of observations using the two methods are independent, i.e., on different subjects, the calculations are very simple and straightforward. Some authors collect repeated data, either as repeated pairs of measurements on the same subject, whose true value of the measured quantity may be changing, or more than one measurement by one or both methods of an unchanging underlying quantity. In this paper we describe methods for analysing such clustered observations, both when the underlying quantity is assumed to be changing and when it is not

    Chorusing, synchrony and the evolutionary functions of rhythm

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    A central goal of biomusicology is to understand the biological basis of human musicality. One approach to this problem has been to compare core components of human musicality (relative pitch perception, entrainment, etc.) with similar capacities in other animal species. Here we extend and clarify this comparative approach with respect to rhythm. First, whereas most comparisons between human music and animal acoustic behavior have focused on spectral properties (melody and harmony), we argue for the central importance of temporal properties, and propose that this domain is ripe for further comparative research. Second, whereas most rhythm research in non-human animals has examined animal timing in isolation, we consider how chorusing dynamics can shape individual timing, as in human music and dance, making group behavior key to understand the adaptive functions of rhythm. To illustrate the interdependence between individual and chorusing dynamics, we present a computational model of chorusing agents relating individual call timing with synchronous group behavior. Third, we distinguish and clarify mechanistic and functional explanations of rhythmic phenomena, often conflated in the literature, arguing that this distinction is key for understanding the evolution of musicality. Fourth, we expand biomusicological discussions beyond the species typically considered, providing an overview of chorusing and rhythmic behavior across a broad range of taxa (orthopterans, fireflies, frogs, birds, and primates). Finally, we propose an "Evolving Signal Timing" hypothesis, suggesting that similarities between timing abilities in biological species will be based on comparable chorusing behaviors. We conclude that the comparative study of chorusing species can provide important insights into the adaptive function(s) of rhythmic behavior in our "proto-musical" primate ancestors, and thus inform our understanding of the biology and evolution of rhythm in human music and language

    Assessing satisfaction with social care services among black and minority ethnic and white British carers of stroke survivors in England

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    Overall satisfaction levels with social care are usually high but lower levels have been reported among black and minority ethnic (BME) service users in England. Reasons for this are poorly understood. This qualitative study therefore explored satisfaction with services among informal carer participants from five different ethnic groups. Fifty-seven carers (black Caribbean, black African, Asian Indian, Asian Pakistani and white British) were recruited from voluntary sector organisations and a local hospital in England, and took part in semi-structured interviews using cognitive interviewing and the critical incident technique. Interviews took place from summer 2013 to spring 2014. Thematic analysis of the interviews showed that participants often struggled to identify specific ‘incidents’, especially satisfactory ones. When describing satisfactory services, participants talked mostly about specific individuals and relationships. Unsatisfactory experiences centred on services overall. When rating services using cognitive interviewing, explicit comparisons with expectations or experiences with other services were common. Highest satisfaction ratings tended to be justified by positive personal characteristics among practitioners, trust and relationships. Lower level ratings were mostly explained by inconsistency in services, insufficient or poor care. Lowest level ratings were rare. Overall, few differences between ethnic groups were identified, although white British participants rated services higher overall giving more top ratings. White British participants also frequently took a more overall view of services, highlighting some concerns but still giving top ratings, while South Asian carers in particular focused on negative aspects of services. Together these methods provide insight into what participants mean by satisfactory and unsatisfactory services. Cognitive interviewing was more challenging for some BME participants, possibly a reflection of the meaningfulness of the concept of service satisfaction to them. Future research should include comparisons between BME and white participants’ understanding of the most positive parts of satisfaction scales and should focus on dissatisfied participants

    ARTIMIS Telephone Travel Information Service: Current Use Patterns and User Satisfaction

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    This report summarizes the results of a phone survey which evaluated the user satisfaction of the telephone traveler information service, ARTIMIS, in Cincinnati/Northern Kentucky. Information was also gathered on the users preference for a 3 versus 7 digit access number, use patterns, and user characteristics. The sample was obtained by intercepting calls to the service during Winter 1999. Users rated the service high. Common suggestions for improvements included longer hours of operation and coverage of more roads suggesting the service is valuable to its users. The travelers perceived that they benefited most by avoiding traffic problems, saving time, and reducing frustration. Of the 65% that would be willing to pay for the service, $0.25 was the average maximum payment they would be willing to make. The respondents had been using the service for an average of 13 months and made on average 4.3 calls per week. The 3 digit number, 211, was the most commonly used and recognized access number. Approximately 80 percent of individuals felt they would personally benefit from a nation-wide 3-digit number for travel information. Landline 211 calls result in an extra cost to operators of the system. Although these callers make less frequent calls, they are also more likely to make route or trip changes resulting in a public overall system benefi

    Mode Bifurcation and Fold Points of Complex Dispersion Curves for the Metamaterial Goubau Line

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    In this paper the complex dispersion curves of the four lowest-order transverse magnetic modes of a dielectric Goubau line (ϵ>0,μ>0\epsilon>0, \mu>0) are compared with those of a dispersive metamaterial Goubau line. The vastly different dispersion curve structure for the metamaterial Goubau line is characterized by unusual features such as mode bifurcation, complex fold points, both proper and improper complex modes, and merging of complex and real modes

    Is there a correlation between infection control performance and other hospital quality measures?

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    Quality measures are increasingly reported by hospitals to the Centers for Medicare and Medicaid Services (CMS), yet there may be tradeoffs in performance between infection control (IC) and other quality measures. Hospitals that performed best on IC measures did not perform well on most CMS non–IC quality measures
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