2,987 research outputs found
Akim Lizakevic v Rime. Predvaraitel'nye materialy
No full textBiografia del diplomatico russo A. Lizakevic sulla base di documenti d'archivio conservati presso l'archivio del MAE russo e nuovi documenti ritrovati in collezioni private italiane (lascito Buonamici di Lucca
Tidal Records as Liquid Climate Archives for Large-Scale Interior Mediterranean Variability
No full textCharacterization of interior ocean variability is necessary for understanding climate. Water mass evolution shapes ocean-atmosphere interactions and contributes to determine timescales for global and regional climate variability. However, a robust assessment of past state and variability of the ocean interior is prevented by sparseness/shortness of historical subsurface observations and uncertainties affecting proxy-based reconstructions. Here, we propose a novel approach to infer past large-scale interior ocean variability with unprecedented accuracy and temporal resolution. It exploits links between stratification determined by “large-scale” water mass distributions and local dynamics. We characterize interannual interior ocean variability in the Mediterranean Sea in the early 20th century contained in tidal measurements in the Strait of Messina, and demonstrate the general applicability of our method, paving the way to a new approach to analyze historical oceanographic records: Regions where different water masses are known to collide can thus act as magnifying glasses for basin-scale interior ocean variability, hence providing “liquid archives” for climatology
DOMENICO TREZZINI E ALTRI MAESTRI TICINESI A PIETROBURGO E TALLINN ALL’INIZIO DEL SETTECENTO
No full textThe activities and work of architect Domenico Trezzini (1670–1734),and the masters that arrived in Russia with him, have been researchedfor a long time, and many contentions have been concretised ordisproven at various times. This article focuses on the issue of howmasters from a single area – Ticino, Switzerland – ended up creatingimportant fortifications, palaces and churches in the Russian Empireduring the reign of Peter the Great at the beginning of 18th century.The author describes the movement of Trezzini and the Ticino mastersfrom Copenhagen to Moscow as reported in various historical sourcesand the works of Danish and Russian researchers
Thulium fiber laser in BPH surgery: Bench to bedside - a systematic review on behalf of YAU Urotechnology Working Group
No full textIntroduction: The Thulium fiber laser (TFL) is a new device that in contrast to the other solid-state YAG-based lasers takes a different approach to pulse formation allowing for two different modes: in the QCW (quasi-continuous wave) function, TFL is convenient for soft tissue surgery and in the SP (Superpulsed) mode it is highly effective in lithotripsy. Thus, unlike the other thulium lasers (Tm : YAG), TFL can be used in a wide range of surgical procedures. Materials and Methods: We conducted a systematic search in 3 databases: Medline, Scopus and Cochrane library. All original articles (both preclinical and clinical) on TFL application in soft tissue surgery were included in data analysis. Results: In terms of its cutting properties, QCW TFL is not inferior to the other thulium lasers, and in fact allows for decreased carbonization (due to lower heat production) compared to continuous lasers (e.g. Tm : YAG). It has been used successfully in endoscopic enucleation of the prostate (EEP) and in en bloc resection of bladder tumors (ERBT). The efficacy and safety of this laser is comparable to TURP and simple prostatectomy, but the recovery period is shorter and the learning curve is slightly superior to other endoscopic procedures. There are no significant differences between TFL and Ho : YAG in terms of efficacy and safety during EEP. Unfortunately, there are no clinical studies that analyse the efficacy and safety of SP TFL in EEP or ERBT. Conclusion: TFL is a safe and effective tool for BPH surgery. In terms of parameters, it is in no way inferior to Tm : YAG or Ho : YAG during EEP. However, TFL surpasses these lasers in terms of usability and serviceability. These advantages are likely to render it more popular over time
Нейронні звичайні диференціальні рівняння для реконструкції часових рядів
No full textAndrosov D. V. Neural ordinary differential equations for time series reconstruction / D. V. Androsov // Радіоелектроніка, інформатика, управління. – 2023. – № 4 (67). – C. 69-75.EN: Context. Neural Ordinary Differential Equations is a deep neural networks family that leverage numerical methods approaches for solving the problem of time series reconstruction, given small amount of unevenly distributed samples.
Objective. The goal of the following research is the synthesis of a deep neural network that is able to solve input signal reconstruction and time series extrapolation task.
Method. The proposed method exhibits the benefits of solving time series extrapolation task over forecasting one. A model that implements encoder-decoder architecture with differential equation solving in latent space, is proposed. The latter approach was proven to demonstrate outstanding performance in solving time series reconstruction task given a small percentage of noisy and uneven distributed input signals. The proposed Latent Ordinary Differential Equations Variational Autoencoder (LODE-VAE) model was benchmarked on synthetic non-stationary data with added white noise and randomly sampled with random intervals between each signal.
Results. The proposed method was implemented via deep neural network to solve time series extrapolation task.
Conclusions. The conducted experiments have confirmed that proposed model solves the given task effectively and is recommended to apply it to solving real-world problems that require reconstructing dynamics of non-stationary processes. The prospects for further research may include the process of computational optimization of proposed models, as well as conducting additional experiments involving different baselines, e. g. Generative Adversarial Networks or attention Networks.
UK: Актуальність. Розглянуто задачу реконструкції нестаціонарних часових рядів на основі моделей кодувальник-декодувальник за допомогою нейронних звичайних диференціальних рівнянь. Об’єктом дослідження є задача відновлення та прогнозування нестаціонарних часовиї рядів та процесів в неперевному часі. Мета роботи – синтез моделі на основі архітектури кодувальник-декодувальник та з використанням моделей типу нейронних звичайних диференційних рівнянь для реконструкції часових рядів по зашумленими, нерівномірно розподіленими у час, вхідними сигналами.
Метод. Запропоновано метод, що реалізує архітектуру кодувальника-декодувальника та аппарат штучних нейронних мереж з розв’язанням диференціальних рівнянь у латентному просторі. Було встановлено, що даний підхід демонструє високу ефективність та якість прогнозів при вирішенні задачі реконструкції часових рядів по зашумленим вхідним сигналам з випадковими інтервалами між сигналами. Запропонована модель варіаційного автокодувальника на з використанням апарату нейронних мереж була протестована на синтетичних нестаціонарних даних з додаваням білим шумом і семплінгом з випадковими інтервалами між кожним сигналом.
Результати. Розроблені показники реалізовані програмно і досліджені при вирішенні задачі реконструкції нестацонарного ряду з сезонністю.
Висновки. Проведені експерименти підтвердили, що запропонована модель ефективно вирішує задану задачу і рекомендується застосовувати її для вирішення реальних завдань, що вимагають реконструкції динаміки нестаціонарних процесів. Перспективи включають в себе подальші дослідження різних архітектур нейронних мереж, окрім рекурентних нейронних мереж та архітектур автокодувальників. Зокрема пропонується використовувати інші підходи генеративного нейромережевого моделювання, як генеративно-змагальні мережі у контексті відновлення структури часового ряд
Author Correction: A portrait of the Higgs boson by the CMS experiment ten years after the discovery
No full textIn the version of this article initially published, CMS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the articl
On the remote sensing of oceanic and atmospheric convection in the Greenland Sea by synthetic aperture radar
No full textIn this paper we discuss characteristic properties of radar signatures of oceanic and atmospheric convection features in the Greenland Sea. If the water surface is clean (no surface films or ice coverage), oceanic and atmospheric features can become visible in radar images via a modulation of the surface roughness, and their radar signatures can be very similar. For an unambiguous interpretation and for the retrieval of quantitative information on current and wind variations from radar imagery with such signatures, theoretical models of current and wind phenomena and their radar imaging mechanisms must be utilized. We demonstrate this approach with the analysis of some synthetic aperture radar (SAR) images acquired by the satellites ERS-2 and RADARSAT-1. In once case, an ERS-2 SAR image an a RADARSAT-1 ScanSAR image exhibit pronounced cell-like signatures with length scales on the order of 10-20 km and modulation depths of about 5-6 dB and 9-10 dB, respectively. Simulations with a numerical SAR imagaing model and various input current and wind fields reveal that the signatures in both images can be expained consistently by wind variations on the order of±2.5 ms, but not by surface current variations on realistic orders of magnitude. Accordingly, the observed features must be atmospheric convection cells. This is confirmed by visible typical cloud patterns in a NOAA AVHRR image of the test scenario. In another case, the presence of an oceanic convective chimney is obvious from in situ data, but no signatures of it are visible in an ERS-2 SAR image. We show by numerical simulations with an oceanic convection model and our SAR imaging model that this is consistent with theoretical predictions, since the current gradients associated with the observed chimney are not sufficiently strong to give rise to significant signatures in an ERS-2 SAR image under the given conditions. Further model results indicate that it should be generally difficult to observe oceanic convection features in the Greenland Sea with ERS-2 or RADARSAT-1 SAR, since their signatures resulting from pure wave-current interaction will be too weak to become visible in the noisy SAR images in most cases. This situation will improve with the availability of future high-resolution SARs such as RADARSAT-2 SAR in fine resolution mode (2004) and TerraSAR-X (2005) which will offer significantly reduced speckle noise fluctuations at comparable spatial resolutions and thus a much better visibility of small image variations on spatial scales on the order of a few hundred meters
Nonhydrostatic Tidal Dynamics in the Area of a Seamount
No full textThe nonhydrostatic boundary problem for an arbitrary three-dimensional domain with a seamount is considered. The problem is integrated into curvilinear boundary-fitted coordinates on a nonuniform grid. In order to identify nonhydrostatic effects the grid is condensed on the slopes of the seamount preserving a coarse resolution in the rest of the domain, where the problem is solved in the hydrostatic approximation. Calculation results for the nonhydrostatic tidal dynamics and hydrology of the Strait of Messina in the area of a seamount are presented
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