3,221 research outputs found

    Managing Waiting Times to Predict No-shows and Cancelations at a Children’s Hospital

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    Purpose: Since long waits in hospitals have been found to be related to high rates of no-shows and cancelations, managing waiting times should be considered as an important tool that hospitals can use to reduce missed appointments. The aim of this study is to analyze patients’ behavior in order to predict no-show and cancelation rates correlated to waiting times. Design/methodology/approach: This study is based on the data from a US children’s hospital, which includes all the appointments registered during one year of observation. We used the call-appointment interval to establish the wait time to get an appointment. Four different types of appointment-keeping behavior and two types of patients were distinguished: arrival, no-show, cancelation with no reschedule, and cancelation with reschedule; and new and established patients. Findings: Results confirmed a strong impact of long waiting times on patients’ appointment-keeping behavior, and the logarithmic regression was found as the best-fit function for the correlation between variables in all cases. The correlation analysis showed that new patients tend to miss appointments more often than established patients when the waiting time increases. It was also found that, depending on the patients’ appointment distribution, it might get more complicated for hospitals to reduce missed appointments as the waiting time is reduced. Originality/value: The methodology applied in our study, which combines the use of regression analysis and patients’ appointment distribution analysis, would help health care managers to understand the initial implications of long waiting times and to address improvement related to patient satisfaction and hospital performance.Peer Reviewe

    Analysis of the frictional slip between a layer and a half-space

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    The numerical analysis of a boundless elastic layer on an elastic halfspace with different material properties under the effects of an uniform surface pressure and a cyclic tangential surface force is presented. Frictional contact conditions are assumed. The study is focussed on the evaluation of the maximum amplitude of the tangential load which produces localized slip between the two regions during the first load cycle but not the subsequent ones. The more simple limit for which no slip exist even for the first cycle is also establishe

    El uso de una solución fundamental compuesta para el cálculo de rigideces de cimentaciones mediante el método de los elementos de contorno

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    El problema de las rigideaes dinámicas de cimentaciones enterradas puede ser abordado por diversos métodos analíticos y numéricos más o me nos aproximados. Se presenta en primer lugar la formulación dinámica del Me todo de los Elementos de Contorno para este tipo de problemas. Se estudia cómo el empleo de una solución fundamental compuesta disminuye el número de términos despreciados al truncar la discretización de la superficie libre.- Se estudian algunos de los valores de las rigideces estáticas y dinámicas,- obtenidos con la solución fundamental compuesta, y se comparan con los - -- correspondientes a la simple. Se apr cia que en la mayor parte de los casos, con la solución compuesta, se produce una reducción del error debido al - - truncamiento en la discretización de la superficie libre del suelo

    Transformation Optics Approach to Plasmon-Exciton Strong Coupling in Nanocavities

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    We investigate the conditions yielding plasmon-exciton strong coupling at the single emitter level in the gap between two metal nanoparticles. A quasi-analytical transformation optics approach is developed that makes possible a thorough exploration of this hybrid system incorporating the full richness of its plasmonic spectrum. This allows us to reveal that by placing the emitter away from the cavity center, its coupling to multipolar dark modes of both even and odd parity increases remarkably. This way, reversible dynamics in the population of the quantum emitter takes place in feasible implementations of this archetypal nanocavity.Comment: 5 pages, 4 figure

    Respuesta dinámica de cimentaciones considerando condiciones de contacto con fricción

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    X Congreso Nacional de Ingeniería Mecánica, celebrado en Madrid en 1992En el presente trabajo se estudia la respuesta en el tiempo de una cimentación superficial situada sobre un semi-espacio, cuando un tren de ondas incide sobre ella. La interacción suelo-cimiento se considera no lineal con posibilidad de separación y deslizamiento, habiéndose supuesto fricción del tipo Coulomb. El algoritmo que se presenta se basa en el Método de los Elementos de Contorno en el dominio del tiempo, y resuelve, para cada intervalo lineal en el que las condiciones de contorno son constantes, el problema difractado.In the present work the time response of a sourface foundation on de half-space when a wave train acts on it, is studied . Non-linear soil-structure interaction. with uplifl .sliding and Colulomb type friction, is considered. The algoritm presented is based on the time domain Boundary Element Method fonnulation, solving the diffracted problem for the differents time steps where the boundary contition are constants

    Joint probability distributions and fluctuation theorems

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    We derive various exact results for Markovian systems that spontaneously relax to a non-equilibrium steady-state by using joint probability distributions symmetries of different entropy production decompositions. The analytical approach is applied to diverse problems such as the description of the fluctuations induced by experimental errors, for unveiling symmetries of correlation functions appearing in fluctuation-dissipation relations recently generalised to non-equilibrium steady-states, and also for mapping averages between different trajectory-based dynamical ensembles. Many known fluctuation theorems arise as special instances of our approach, for particular two-fold decompositions of the total entropy production. As a complement, we also briefly review and synthesise the variety of fluctuation theorems applying to stochastic dynamics of both, continuous systems described by a Langevin dynamics and discrete systems obeying a Markov dynamics, emphasising how these results emerge from distinct symmetries of the dynamical entropy of the trajectory followed by the system For Langevin dynamics, we embed the "dual dynamics" with a physical meaning, and for Markov systems we show how the fluctuation theorems translate into symmetries of modified evolution operators.Comment: 39 pages, 1 figure. Minor revision, as suggested by referees. A couple of references and equations added. Acknowledgements slightly modifie

    Auxiliary Signal-Based Distance Protection in Inverter-Dominated Power Systems

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    Power system protection schemes today rely on currents rising by several orders of magnitude when faults occur. In inverter-dominated power systems, a fault current might be just a few percent larger than normal, making fault detection more difficult. One solution is for the inverter to slightly perturb its output current and/or voltage, i.e., to inject an auxiliary signal, so as to make the system's behavior under faults easier to distinguish from normal. In this paper, we optimize auxiliary signals for fault detection with distance relays. We begin with a standard auxiliary signal design problem for generic static systems. We use duality to reformulate the problem as a bilinear program, which we solve using the convex-concave procedure. We implement the framework in an example based on distance protection, in which the auxiliary signal is negative sequence current

    A comparison of BPMN 2.0 with other notations for manufacturing processes

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    In order to study their current practices and improve on them, manufacturing firms need to view their processes from several viewpoints at various abstraction levels. Several notations have been developed for this purpose, such as Value Stream Mappings or IDEF models. More recently, the BPMN 2.0 standard from the Object Management Group has been proposed for modeling business processes. A process organizes several activities (manual or automatic) into a single higher-level entity, which can be reused elsewhere in the organization. Its potential for standardizing business interactions is well-known, but there is little work on using BPMN 2.0 to model manufacturing processes. In this work some of the previous notations are outlined and BPMN 2.0 is positioned among them after discussing it in more depth. Some guidelines on using BPMN 2.0 for manufacturing are offered, and its advantages and disadvantages in comparison with the other notations are presented
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