804 research outputs found

    Tension and Compression Micropile Load Tests in Gravelly Sand

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    Micropiles were selected for several upgrades to a paper machine at the Nippon Paper Industries USA Company in Port Angeles, Washington. This paper presents several aspects of the micropile design and subsequent load test performance for two separate upgrades at the paper mill. The micropile load tests, performed in tension and compression, provide a reference for micropile performance in medium dense to dense, gravelly sand. Comparison of the load test performance suggests that the common assumption of neglecting the contribution of end-bearing resistance does not adequately model micropile behavior. Additionally, evidence is presented for load transfer through the micropile casing. The load test performance is interpreted in the framework of a simple, global stiffness degradation technique, which provides an estimate of bond stresses. The analyses suggest that the mode of loading (e.g., tension or compression) influences the load transfer properties for the small diameter micropiles

    Cooperative AI: machines must learn to find common ground

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    Artificial-intelligence assistants and recommendation algorithms interact with billions of people every day, influencing lives in myriad ways, yet they still have little understanding of humans. Self-driving vehicles controlled by artificial intelligence (AI) are gaining mastery of their interactions with the natural world, but they are still novices when it comes to coordinating with other cars and pedestrians or collaborating with their human operators

    Invasion speeds for structured populations in fluctuating environments

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    We live in a time where climate models predict future increases in environmental variability and biological invasions are becoming increasingly frequent. A key to developing effective responses to biological invasions in increasingly variable environments will be estimates of their rates of spatial spread and the associated uncertainty of these estimates. Using stochastic, stage-structured, integro-difference equation models, we show analytically that invasion speeds are asymptotically normally distributed with a variance that decreases in time. We apply our methods to a simple juvenile-adult model with stochastic variation in reproduction and an illustrative example with published data for the perennial herb, \emph{Calathea ovandensis}. These examples buttressed by additional analysis reveal that increased variability in vital rates simultaneously slow down invasions yet generate greater uncertainty about rates of spatial spread. Moreover, while temporal autocorrelations in vital rates inflate variability in invasion speeds, the effect of these autocorrelations on the average invasion speed can be positive or negative depending on life history traits and how well vital rates ``remember'' the past

    Improving Quality And Diffusing Best Practices: The Case Of Schizophrenia

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    The slow diffusion of empirically supported treatments and the rapid diffusion of treatments lacking empirical support play a significant role in the quality gap in the care of people with severe mental illnesses. Further, the rapid diffusion of treatments of low cost-effectiveness limits the system's ability to provide the full gamut of high-value treatments available to treat this vulnerable population. Using the case of schizophrenia as an illustrative case study, we review the context in which these paradoxical patterns of diffusion have occurred and propose policy solutions

    Crude incidence in two-phase designs in the presence of competing risks.

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    BackgroundIn many studies, some information might not be available for the whole cohort, some covariates, or even the outcome, might be ascertained in selected subsamples. These studies are part of a broad category termed two-phase studies. Common examples include the nested case-control and the case-cohort designs. For two-phase studies, appropriate weighted survival estimates have been derived; however, no estimator of cumulative incidence accounting for competing events has been proposed. This is relevant in the presence of multiple types of events, where estimation of event type specific quantities are needed for evaluating outcome.MethodsWe develop a non parametric estimator of the cumulative incidence function of events accounting for possible competing events. It handles a general sampling design by weights derived from the sampling probabilities. The variance is derived from the influence function of the subdistribution hazard.ResultsThe proposed method shows good performance in simulations. It is applied to estimate the crude incidence of relapse in childhood acute lymphoblastic leukemia in groups defined by a genotype not available for everyone in a cohort of nearly 2000 patients, where death due to toxicity acted as a competing event. In a second example the aim was to estimate engagement in care of a cohort of HIV patients in resource limited setting, where for some patients the outcome itself was missing due to lost to follow-up. A sampling based approach was used to identify outcome in a subsample of lost patients and to obtain a valid estimate of connection to care.ConclusionsA valid estimator for cumulative incidence of events accounting for competing risks under a general sampling design from an infinite target population is derived

    Automating unobtrusive personalized services in ambient media environments

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-013-1634-2In the age of ambient media, people are surrounded by lots of physical objects (media objects) for rendering the digital world in the natural environment. These media objects should interact with users in a way that is not disturbing for them. To address this issue, this work presents a design and automation strategy for augmenting the world around us with personalized ambient media services that behave in a considerate manner. That is, ambient services are capable of adjusting its obtrusiveness level (i.e., the extent to which each service intrudes the user¿s mind) by using the appropriate media objects for each user¿s situation.This work has been developed with the support of MICINN, under the project EVERYWARE TIN2010-18011, and the support of the Christian Doppler Forschungsgesellschaft and the BMWFJ, Austria.Serral Asensio, E.; Gil Pascual, M.; Valderas Aranda, PJ.; Pelechano Ferragud, V. (2014). Automating unobtrusive personalized services in ambient media environments. Multimedia Tools and Applications. 71(1):159-178. https://doi.org/10.1007/s11042-013-1634-2S159178711Bencomo N, Grace P, Flores-Cortés CA, Hughes D, Blair GS (2008) Genie: supporting the model driven development of reflective, component-based adaptive systems. In: ICSE, pp 811–814Blumendorf M, Lehmann G, Albayrak S (2010) Bridging models and systems at runtime to build adaptive user interfaces. In: Proc. of EICS 2010. 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