369 research outputs found

    Hierarchical Bayes Estimation of Reliability Indexes of Cold Standby Series System under General Progressive Type II Censoring Scheme

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    In this paper, hierarchical Bayes approach is presented for estimation and prediction of reliability indexes and remaining lifetimes of a cold standby series system under general progressive Type II censoring scheme. A simulation study has been carried out for comparison purpose. The study will help reliability engineers in various industrial series system setups

    Preference of Estimation Approach for Rayleigh Progressive Type II Data

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    This paper compare the performance of the empirical Bayes and generalized maximum likelihood estimation approaches in context of progressively Type II censored data from one parameter Rayleigh distribution. The generalized maximum likelihood and empirical Bayes estimates of scale parameter, reliability function, and failure rate function are compared using risk efficiency criterion. The empirical Bayes estimates are considered with respect to squared error loss function. The wind speed data is presented to illustrate the proposed estimation approaches, and an extensive Monte Carlo simulated study is done to compare the empirical Bayes and Generalized maximum likelihood estimates. The study indicates that the empirical Bayesian approach using squared error loss function is preferable than the generalized maximum likelihood approach for the estimation of reliability performances. Keywords: Progressively Type II censored samples, generalized maximum likelihood estimation, squared error loss function, empirical Bayes estimation, Risk efficiency, Monte Carlo simulation.

    Impulse: a Formal Characterization of Story

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    Good Timing for Computational Models of Narrative Discourse

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    The temporal order in which story events are presented in discourse can greatly impact how readers experience narrative; however, it remains unclear how narrative systems can leverage temporal order to affect comprehension and experience. We define structural properties of discourse which provide a basis for computational narratologists to reason about good timing, such as when readers learn about event relationships

    Distribution of machine information using Blackboard designed component for remote monitoring of reconfigurable manufacturing systems

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    A blackboard-based design for a system component called the "Broadcaster" is described in this paper. It supports remote monitoring of reconfigurable manufacturing systems using a novel system architecture coupled with the Component-Based system paradigm. The design of this component has been evaluated using a case study on a web services-enabled test rig funded by the Ford Motor Company, U. K. The test rig has been implemented using a fully distributed control device called FTB, designed by the Schneider Electric Company. Evaluation of this component has been carried out using three scenario test cases which demonstrate the potentials offered when deploying this solution to a real production environment. The system component not only operates in a heterogeneous reconfigurable manufacturing environment, offering a vendor-independent solution to monitoring machines, but it also supports remote monitoring of the machines throughout their development and management lifecycles

    “Broadcaster”: An architectural description of a prototype supporting real-time remote data propagation in distributed manufacturing

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    Globalisation of manufacturing activities tend to geographically distribute manufacturing entities, resulting into each entity adopting its own mechanism, for aggregating and analysing real-time shop floor machines' information. The enterprise systems normally employ sophisticated and computationally expensive techniques to access this data, even if they operate remotely having limited network connectivity and system legacies. There is a need to propagate machine information in soft real-time basis to these entities regardless of their geographic locations and / or mechanisms. Authors are presenting an architectural description of a prototype system called the ldquoBroadcasterrdquo which efficiently distributes manufacturing machine information to a number of remotely located global engineering partners. This prototype addresses the emergent system issues like maintainability, reliability, integrity, robustness, flexibility and performance using a heterogeneous composition of ldquoBlackboardrdquo repository model with an event-driven invocation technique, implemented using interface-based strategy. The design and implementation assumes the control environment description to be engineered using the component-based system paradigm. Presently, the prototype is evaluated on a demonstration test rig provided by the Ford Motor Company, which is implemented using a fully Web services distributed control device called FTB, designed by the Schneider Electric Company. Based on the evaluation from the implementation stage, authors have justified and concluded the paper highlighting the key benefits of this approach, and described any future research that is to be carried out

    A WORLDWIDE 3D GCP DATABASE INHERITED FROM 20 YEARS OF MASSIVE MULTI-SATELLITE OBSERVATIONS

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    Abstract. High location accuracy is a major requirement for satellite image users. Target performance is usually achieved thanks to either specific on-board satellite equipment or an auxiliary registration reference dataset. Both methods may be expensive and with certain limitations in terms of performance. The Institut national de l'information géographique et forestiÚre (IGN) and Airbus Defence and Space (ADS) have worked together for almost 20 years, to build reference data for improving image location using multi-satellite observations. The first geometric foundation created has mainly used SPOT 5 High Resolution Stereoscopic (HRS) imagery, ancillary Ground Control Points (GCP) and Very High Resolution (VHR) imagery, providing a homogenous location accuracy of 10m CE90 almost all over the world in 2010.Space Reference Points (SRP) is a new worldwide 3D GCP database, built from a plethoric SPOT 6/7 multi-view archive, largely automatically processed, with cloud-based technologies. SRP aims at providing a systematic and reliable solution for image location (Unmanned Aerial Vehicle, VHR satellite imagery, High Altitudes Pseudo-Satellite
) and similar topics thanks to a high-density point distribution with a 3m CE90 accuracy.This paper describes the principle of SRP generation and presents the first validation results. A SPOT 6/7 smart image selection is performed to keep only relevant images for SRP purpose. The location of these SPOT 6/7 images is refined thanks to a spatiotriangulation on the worldwide geometric foundation, itself improved where needed. Points making up the future SRP database are afterward extracted thanks to classical feature detection algorithms and with respect to the expected density. Different filtering methods are applied to keep the best candidates. The last step of the processing chain is the formatting of the data to the delivery format, including metadata. An example of validation of SRP concept and specification on two tests sites (Spain and China) is then given. As a conclusion, the on-going production is shortly presented

    Persistent Homology Over Directed Acyclic Graphs

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    We define persistent homology groups over any set of spaces which have inclusions defined so that the corresponding directed graph between the spaces is acyclic, as well as along any subgraph of this directed graph. This method simultaneously generalizes standard persistent homology, zigzag persistence and multidimensional persistence to arbitrary directed acyclic graphs, and it also allows the study of more general families of topological spaces or point-cloud data. We give an algorithm to compute the persistent homology groups simultaneously for all subgraphs which contain a single source and a single sink in O(n4)O(n^4) arithmetic operations, where nn is the number of vertices in the graph. We then demonstrate as an application of these tools a method to overlay two distinct filtrations of the same underlying space, which allows us to detect the most significant barcodes using considerably fewer points than standard persistence.Comment: Revised versio

    Surgical resection of a giant peripheral ossifying fibroma in mouth floor managed with fiberscopic intubation

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    Tracheal intubation for general anesthesia can sometimes be difficult in patients with a large mass in the mouth floor. Preoperative evaluation of the patient's airway is most important when treating large oral disease

    Reaction norm analysis reveals rapid shifts toward delayed maturation in harvested Lake Erie yellow perch (Perca flavescens )

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    Harvested marine fish stocks often show a rapid and substantial decline in the age and size at maturation. Such changes can arise from multiple processes including fisheries‐induced evolution, phenotypic plasticity, and responses to environmental factors other than harvest. The relative importance of these processes could differ systematically between marine and freshwater systems. We tested for temporal shifts in the mean and within‐cohort variability of age‐ and size‐based maturation probabilities of female yellow perch (Perca flavescens Mitchill) from four management units (MUs) in Lake Erie. Lake Erie yellow perch have been commercially harvested for more than a century, and age and size at maturation have varied since sampling began in the 1980s. Our analysis compared probabilistic maturation reaction norms (PMRNs) for cohorts when abundance was lower and harvest higher (1993–1998) to cohorts when abundance was higher and harvest lower (2005–2010). PMRNs have been used in previous studies to detect signs of evolutionary change in response to harvest. Maturation size threshold increased between the early and late cohorts, and the increases were statistically significant for the youngest age in the western MU1 and for older ages in the eastern MU3. Maturation envelope widths, a measure of the variability in maturation among individuals in a cohort, also increased between early and late cohorts in the western MUs where harvest was highest. The highest rates of change in size at maturation for a given age were as large or larger than rates reported for harvested marine fishes where declines in age and size at maturation have been observed. Contrary to the general observation of earlier maturation evolving in harvested stocks, female yellow perch in Lake Erie may be rapidly evolving delayed maturation since harvest was relaxed in the late 1990s, providing a rare example of possible evolutionary recovery
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