246,687 research outputs found

    Diagnostic Application for Development of Custom ATCA Carrier Board for LLRF

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    The Advanced Telecommunications Computing Architecture (ATCA) standard describes a powerful and efficient platform. With multiple integrated solutions like redundancies and intelligent control mechanisms this technology is characterized with reliability estimated at the level of 99.99999 percent. These features make the standard perfect for use in projects like the Free Electron Laser in Hamburg (FLASH) and the X-ray Free Electron Laser (X-FEL) in order to help them meet the requirements of high availability and reliability. The ATCA standard incorporates advanced control systems defined in the Intelligent Platform Management Interface (IPMI) specification as one of the key elements. The entire ATCA implementation retains its functionality as long as the IPMI remains operational. The complexity level of the application increases, which results in preparing it to run and debugging being more difficult to perform. At the same time, only scrupulous elimination of any kind of possible deficiencies can enable the ATCA implementation to offer the desired level of reliability. Thus, diagnostics become crucial, which creates a need for additional tools performing these tasks during the preparations of both hardware and software for the ATCA application. The paper presents application aiding in development of the prototype Carrier Board by enabling the user of external PC station to perform diagnostic and control activities over the Board. It helps in examining all its components at the stage of running the Board, as well as in further operation analysis

    How Effective are Toll Roads in Improving Operational Performance?

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    The main focus of this research is to develop a systematic analytical framework and evaluate the effect of a toll road on region’s traffic using travel time and travel time reliability measures. The travel time data for the Triangle Expressway in Raleigh, North Carolina, United States was employed for the assessment process. The spatial and temporal variations in the travel time distributions on the toll road, parallel alternate route, and near-vicinity cross-streets were analyzed using various travel time reliability measures. The results indicate that the Triangle Expressway showed a positive trend in reliability over the years of its operation. The parallel route reliability decreased significantly during the analysis period, whereas the travel time reliability of cross-streets showed a consistent trend. The stabilization of travel time distributions and the reliability measures over different years of toll road operation are good indicators, suggesting that further reduction in performance measures may not be seen on the near vicinity corridors. The findings from link-level and corridor-level analysis may help with transportation system management, assessing the influence of travel demand patterns, and evaluating the effect of planned implementation of similar projects

    An availability study for a SME

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    A case study of an availability analysis for a small commercial company is presented. The analysis was carried out to meet a customer requirement for the availability of an electronic ground-based system in a benign environment. Availability calculations were based on failure data provided and an explanation of the methodology and problems encountered and dealt with are discussed. The methodology includes failure classification according to MIL-HDBK-781A and how it may be used to promote and develop internal processes. A commentary on the background to reliability/availability specification is provided and a number of recommendations for monitoring reliability and availability are given

    Reliability-based economic model predictive control for generalized flow-based networks including actuators' health-aware capabilities

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    This paper proposes a reliability-based economic model predictive control (MPC) strategy for the management of generalized flow-based networks, integrating some ideas on network service reliability, dynamic safety stock planning, and degradation of equipment health. The proposed strategy is based on a single-layer economic optimisation problem with dynamic constraints, which includes two enhancements with respect to existing approaches. The first enhancement considers chance-constraint programming to compute an optimal inventory replenishment policy based on a desired risk acceptability level, leading to dynamically allocate safety stocks in flow-based networks to satisfy non-stationary flow demands. The second enhancement computes a smart distribution of the control effort and maximises actuators’ availability by estimating their degradation and reliability. The proposed approach is illustrated with an application of water transport networks using the Barcelona network as the considered case study.Peer ReviewedPostprint (author's final draft
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