905 research outputs found

    Large Deviations of Products of Random Topical Operators

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    A topical operator on R^d is one which is isotone and homogeneous. Let {A(n) : n ≄ 1} be a sequence of i.i.d. random topical operators such that A(1) is almost surely bounded for large n. If the projective radius of A(n) {x(n) : n ≄ 1} is a sequence of vectors given by x(n) = A(n)...A(1)x_0, for some fixed initial condition x_0, then the sequence {x(n)/n : n ≄ 1} satisfies a weak large deviation principle. As corollaries of this result we obtain large deviation principles for products of certain random aperiodic max-plus and min-plus matrix operators, and for products of certain random aperiodic non-negative matrix operators

    Large Deviations and Transient Multiplexing at a Buffered Resource

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    In this paper we discuss asymptotics associated with a large number of sources using a resource in a compact time interval. A large deviations condition is placed on the sum of the vectors that describe the stochastic behaviour of the sources and large deviations results deduced about the probability of exhaustion of the resource. This approach allows us to consider sources which are highly non-stationary in time. The examples in mind are a single server queue and a form of the Cramer-Lundburg model from risk theory. Connection is made with past work on stability of queues and effective bandwidths. A number of examples are presented to illustrate the strengths of this approach

    Measurement Based Resource Allocation for Multimedia Applications

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    Modern networks are now capable of guaranteeing a consistent Quality of Service (QoS) to multimedia traffic streams. A number of major operating system vendors are also working hard to extend these guarantees into the end-system. In both cases, however, there remains the problem of determining a service rate sufficient to ensure the desired Quality of Service. Source modelling is not a sustainable approach in the network case and it is even less feasible to model the demands of multimedia applications. The ESPRIT Measure project is successfully using online measurement and estimation to perform resource allocation for bursty traffic in ATM networks. In this paper we consider the applicability of the same theory to resource allocation in a multimedia operating system which offers QoS guarantees to its applications

    Towards a More Robust Lower Neck Compressive Injury Tolerance - An Approach Combining Multiple Test Methodologies

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    Objective.The compressive tolerance of the cervical spine has traditionally been reported in terms of axial force at failure. Previous studies suggest that axial compressive force at failure is particularly sensitive to the alignment of the cervical vertebra and the end conditions of the test methodology used. The present study was designed to develop a methodology to combine the data of previous experiments into a diverse dataset utilizing multiple test methods to allow for the evaluation of the robustness of current and proposed eccentricity based injury criteria. Methods. Data was combined from two studies composed of dynamic experiments including whole cervical spine and head kinematics that utilized different test methodologies with known end conditions, spinal posture, injury outcomes and measured kinetics at the base of the neck. Loads were transformed to the center of the C7-T1 intervertebral disc and the eccentricity of the sagittal plane resultant force relative to the center of the disc was calculated. The correlation between sagittal plane resultant force and eccentricity at failure was evaluated and compared to the correlation between axial force and sagittal plane moment and axial force alone. Results. Accounting for the eccentricity of the failure loads decreased the scatter in the failure data when compared to the linear combination of axial force and sagittal plane moment and axial force alone. A correlation between axial load and sagittal plane flexion moment at failure (R2 = 0.44) was identified. The sagittal plane extension moment at failure did not have an identified correlation with the compressive failure load for the tests evaluated in this data set (R2 = 0.001). The coefficients of determination for the linear combinations of sagittal plane resultant force with anterior and posterior eccentricity are 0.56 and 0.29 respectively. These correlations are an improvement compared to the combination of axial force and sagittal plane moment. Conclusions. Results using the outlined approach indicate that the combination of lower neck sagittal plane resultant force and the anterior-posterior eccentricity at which the load is applied generally correlate with the type of cervical damage identified. These results show promise at better defining the tolerance for compressive cervical fractures in male Post Mortem Human Subjects (PMHS) than axial force alone. The current analysis requires expansion to include more tolerance data so the robustness of the approach across various applied loading vectors and cervical postures can be evaluated

    The pop-up research centre - Challenges and opportunities

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    Objectives: This article sets out to describe the concept of the “pop-up” research centre as a means to promote and develop radiography research locally, nationally and internationally, and to empower professional colleagues to set up similar initiatives in the future. Key findings: A detailed overview of the development and management of “pop-up” research is provided based on the experiences of the authors, including specific examples. Matters such as study design, approvals, equipment and software, environment, participant recruitment and management, research teams and activity costs are discussed. Quantifiable benefits of “pop-up” research such as resultant peer reviewed publications, development of researchers' skills and potential collaborations are described. A number of “soft skill” benefits are also apparent and include enhanced organisational profiles, team building and the development of leadership skills. Conclusions: “Pop-up” research centres are a valuable option for conducting research and offer the radiography profession an achievable mechanism to increase and enhance research activity. However, careful planning and execution are essential

    Understanding Face and Shame: A Servant-Leadership and Face Management Model

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    Clergy can have a negative impact on churches and other individuals when they knowingly or unknowingly attempt to save face, that is, try to protect their standing or reputation. The desire to gain face and the fear of losing face and feeling ashamed will likely permeate clergy’s decision-making processes without even being noticed. This study explores the essence of face and face management and the relationship between face management and two characteristics of servant-leadership—awareness and healing—in both Chinese and American churches through the methodology of hermeneutic phenomenology. Prior to this study, to my knowledge, no hermeneutic phenomenological research of face management has been conducted in a church setting. Through a review of the literature, four areas are explored: face and shame, face management, servant-leadership, and face, shame, and face management within the church. This study obtained approval from the Institutional Review Board and informed consent from the participants. Three Chinese and three American Christian ministers were chosen to complete a question sheet and participate in two semi-structured interview sessions. A first cycle of open coding and second cycle of pattern coding were used during data analysis. Face experiences are discussed in light of eight major themes: body, triggers, becoming, face concepts, strategies, emotions, servant-leadership, and the church. Findings from the study help build a servant-leadership and face management model, which can offer an anchored approach for clergy and pastoral counselors to address face and shame and to develop therapeutic interventions

    Restrictive ID policies: implications for health equity

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    We wish to thank Synod Community Services for their critical work to develop, support, and implement a local government-issued ID in Washtenaw County, MI. We also thank Yousef Rabhi of the Michigan House of Representatives and Janelle Fa'aola of the Washtenaw ID Task Force, Lawrence Kestenbaum of the Washtenaw County Clerk's Office, Sherriff Jerry Clayton of the Washtenaw County Sherriff's Office, and the Washtenaw ID Task Force for their tireless commitment to developing and supporting the successful implementation of the Washtenaw ID. Additionally, we thank Vicenta Vargas and Skye Hillier for their contributions to the Washtenaw ID evaluation. We thank the Curtis Center for Research and Evaluation at the University of Michigan School of Social Work, the National Center for Institutional Diversity at the University of Michigan, and the University of California-Irvine Department of Chicano/Latino Studies and Program in Public Health for their support of the Washtenaw ID community-academic research partnership. Finally, we thank the reviewers for their helpful comments on earlier drafts of this manuscript. (Curtis Center for Research and Evaluation at the University of Michigan School of Social Work; National Center for Institutional Diversity at the University of Michigan; University of California-Irvine Department of Chicano/Latino Studies; Program in Public Health)https://link.springer.com/content/pdf/10.1007/s10903-017-0579-3.pdfPublished versio
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