47 research outputs found

    The impact of data filtration on the accuracy of multiple time-domain forecasting for photovoltaic power plants generation

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    The paper reports the forecasting model for multiple time-domain photovoltaic power plants, developed in response to the necessity of bad weather days’ accurate and robust power generation forecasting. We provide a brief description of the piloted short-term forecasting system and place under close scrutiny the main sources of photovoltaic power plants’ generation forecasting errors. The effectiveness of the empirical approach versus unsupervised learning was investigated in application to source data filtration in order to improve the power generation forecasting accuracy for unstable weather conditions. The k-nearest neighbors’ methodology was justified to be optimal for initial data filtration, based on the clusterization results, associated with peculiar weather and seasonal conditions. The photovoltaic power plants’ forecasting accuracy improvement was further investigated for a one hour-ahead time-domain. It was proved that operational forecasting could be implemented based on the results of short-term day-ahead forecast mismatches predictions, which form the basis for multiple time-domain integrated forecasting tools. After a comparison of multiple time series forecasting approaches, operational forecasting was realized based on the second-order autoregression function and applied to short-term forecasting errors with the resulting accuracy of 87%. In the concluding part of the article the authors from the points of view of computational efficiency and scalability proposed the hardware system composition. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

    An approach to verification and validation of MHD codes for fusion applications

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    We propose a new activity on verification and validation (V&V) of MHD codes presently employed by the fusion community as a predictive capability tool for liquid metal cooling applications, such as liquid metal blankets. The important steps in the development of MHD codes starting from the 1970s are outlined first and then basic MHD codes, which are currently in use by designers of liquid breeder blankets, are reviewed. A benchmark database of five problems has been proposed to cover a wide range of MHD flows from laminar fully developed to turbulent flows, which are of interest for fusion applications: (A) 2D fully developed laminar steady MHD flow, (B) 3D laminar, steady developing MHD flow in a non-uniform magnetic field, (C) quasi-two-dimensional MHD turbulent flow, (D) 3D turbulent MHD flow, and (E) MHD flow with heat transfer (buoyant convection). Finally, we introduce important details of the proposed activities, such as basic V&V rules and schedule. The main goal of the present paper is to help in establishing an efficient V&V framework and to initiate benchmarking among interested parties. The comparison results computed by the codes against analytical solutions and trusted experimental and numerical data as well as code-to-code comparisons will be presented and analyzed in companion paper/paper

    Solving the Noether procedure for cubic interactions of higher spins in (A)dS

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    The Noether procedure represents a perturbative scheme to construct all possible consistent interactions starting from a given free theory. In this note we describe how cubic interactions involving higher spins in any constant-curvature background can be systematically derived within this framework.Comment: 17 pages, LaTex. Invited contribution to the J. Phys. A special volume on "Higher Spin Theories and AdS/CFT" edited by M. Gaberdiel and M. A. Vasiliev. Final version to appear in J. Phys.

    Role of the Radiophysical Research Institute (NIRFI) for promoting and teaching science in Russia

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    International audienceWe present, how the Radiophysical Research Institute (NIRFI) has conducted work on the popularization of its scientific achievements in the areas of astronomy, solar physics, the Sun-Earth connection and associated geophysics

    AORTIC VALVE REPLACEMENT IN PATIENT WITH FUNCTIONING CORONARY ARTERY BYPASS GRAFTS

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    We report the clinical case of aortic valve replacement for severe aortic insufficiency in patient who previously was subjected to coronary bypass grafting, with functioning grafts, including internal thoracic artery graft. The procedure was performed from the upper ministernotomy with peripheral (femoral) cardiopulmonary bypass

    Radio Astronomical and Radiophysical Studies in the Near-Earth Space in the Radiophysical Research Institute

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    The paper describes possibilities of the experimental investigations of the near-Earth space by the facilities of the Radiophysical Research Institute at Nizhny Novgorod. We describe the experimental equipment, development of the research methods and some recent results

    Outcomes of the minimally invasive aortic valve replacement

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    The OBJECTIVE was to demonstrate clinical outcomes of minimally invasive aortic valve replacement (MIAVR).MATERIAL AND METHODS. We retrospectively analyzed surgical results of treatment of patients underwent isolated AVR in our Institution between 2006 and 2018. Overall number of operations was 122; 56 of patient were operated via upper ministernotomy approach. Preoperative characteristics were similar in both groups.RESULTS. In our series MIAVR procedures had prolonged CPB and aortic cross clamping time, what significantly contributed to the increase in manifestations of heart failure in the early postoperative period, but didn’t affect the perioperative mortality and major morbidity rates. MIAVR led to reduction in postoperative blood loss and perioperative red blood cell transfusion rate. Most severe complications occurred in frail patients older than 75 years, and in those with extensive aortic annular calcification.CONCLUSION. MIAVR was the safe and reproducible surgical intervention and rarely led to significant complications in low-risk patients. Prolonged CPB time adversely affected the frequency of significant complications, especially in elderly patients. Although, selected high risk patients might benefit with MIAVR
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