Computational power poses heavy limitations to the achievable problem size for Kriging. In separate research lines, Kriging algorithms based on FFT, the separability of certain covariance functions, ...and low-rank representations of covariance functions have been investigated, all three leading to drastic speedup factors. The current study combines these ideas, and so combines the individual speedup factors of all ideas. This way, we reduce the mathematics behind Kriging to a computational complexity of only
, where
L
∗
is the number of points along the longest edge of the involved lattice of estimation points, and
d
is the physical dimensionality of the lattice. For separable (factorized) covariance functions, the results are exact, and nonseparable covariance functions can be approximated well through sums of separable components.
Only outputting the final estimate as an explicit map causes computational costs of
, where
n
is the number of estimation points. In illustrative numerical test cases, we achieve speedup factors up to 10
8
(eight orders of magnitude), and we can treat problem sizes of up to 15 trillion and two quadrillion estimation points for Kriging and spatial design, respectively, within seconds on a contemporary desktop computer. The current study assumes second-order stationarity and simple Kriging on a regular, equispaced lattice, without working with restricted neighborhoods. Extensions to many other cases are straightforward.
The concentrations of Pb, Cd, Ni, Cu, and Zn were determined in the invasive pink salmon that came to spawn into the Kola and Tuloma rivers of the Kola Peninsula, flowing into the Barents Sea, in ...July 2019. The content of trace elements in the organs and tissues of pink salmon introduced in the Euro-Arctic waters of Russia was compared to those of the pink salmon from its native range, which returned to spawn in the rivers of the Sakhalin and Iturup islands in 2016–2018. It has been established that concentrations of Zn, Cu, and Ni noticeably predominate in all organs and tissues of introduced pink salmon, whereas Pb and Cd predominate in the Sea of Okhotsk pink salmon. Obviously, the differences in the microelement composition in fish are caused by environmental conditions. In the Barents Sea, they are formed under the influence of the Gulf Stream, as well as the anthropogenic impact of the Kola Peninsula, which is characterized by the extraction, processing, and smelting of a number of metals, primarily Ni and Cu, as well as Zn. In the Sakhalin-Kuril basin, the specificity of the environment and the microelement composition of salmon are due to the influence of natural factors—volcanism and upwellings. Schools of pink salmon during feeding and migration in the Pacific Ocean cross a high-nutrient and at the same time geochemically impact natural zone formed by the Kuril Ridge and the Kuril-Kamchatka Depression, which supplies chemical elements to surface waters. Here, the concentration of Pb is most markedly increased in fish. The development of the introduced pink salmon in the new area is facilitated by the recent increase in temperature in the waters of the North Atlantic, so the amount of fish production in it will increase. The mastering of pink salmon in new feeding places sets before scientists the task of monitoring the dynamics of its abundance and taking adequate measures for fishery regulation and fish quality control.
Abstract
The metals (Cu, Pb, Cd, Ni, Zn and Fe) in Pacific salmon were determined: Masu from the southeast Sakhalin Island coast, collected in 2017, Chum from the of Okhotsk and Japan Seas, collected ...in 2018-2019 in cages of salmon fish hatcheries and Sockey collected from two bays of the southeastern coast Kamchatka before entering the rivers, in 2021. It was established that the content of Zn, Ni, and Fe noticeably predominate in the organs and tissues of Cherry and Chum from the Sea of Japan, while Cd and Pb concentrations predominate in the organism of the Sea of Okhotsk Chum. The largest amount of copper was found in the organism of Sockey from Kamchatka bays. according to the content of toxic elements (Pb and Cd), all types of salmon meet the sanitary requirements of the Russia for seafood. Probably, the reason for the established difference is the geochemical environmental conditions formed in the closed Sea of Japan under the influence of anthropogenic and terrigenous factors, the influence of natural factors - volcanism and upwellings - in the Sakhalin-Kurilsky basin of the Sea of Okhotsk, also the increased background copper content in the Kamchatka soils because of volcanic activities.
Abstract
The article discusses the results of a study on the enrichment of artificial feeds with dry biomass of methanotrophic bacteria of 10 and 20% concentration and fatty acids (treatment “Arfit”, ...linseed oil). The data on the increase in body length and weight, the survival rate of Siberian sturgeon juveniles, depending on the applied preparations introduced, are presented. The best results were obtained when 10% of dry biomass of methanotrophic bacteria and HUFA were added to the feed (acceleration of weight growth by 44%, linear growth by 38%). The presented results are aimed at developing some elements of the technology for enriching artificial feeds with microbiosynthesis products.
Polyphenols from Suaeda acuminata Litvinenko, Yu. A.; Seitimova, G. A.; Burasheva, G. Sh ...
Chemistry of natural compounds,
01/2019, Letnik:
55, Številka:
1
Journal Article
Brushless dc electric motors have found application in various branches of domestic technology, including in highly important aviation applications, the creation of the electrical complexes of which ...requires minimizing the weight and size indicators of all elements. However, due to the fact that such systems are often constructed on the basis of complex unique transmission mechanisms, their optimization is reduced to the constructive elaboration of the executive electric motor. For electromechanical converters with nonoverlapping concentrated multisection windings used in multipole machines, it is possible to achieve a significant reduction in the total mass by varying the height of the teeth and the length of the machine, taking into account the accepted volume restrictions. This kind of approach to the design of electric machines with a fractional number of slots per pole and phase allows one to create a magnetic system that provides a minimum of the mass of the product while maintaining the required electromechanical parameters by changing the tooth zone. The results obtained will make it possible, even at the stage of creating the sketch appearance of the magnetic system of the executive electric motor, to determine the optimal ratios of the parameters of the magnetic circuit, taking into account the possible minimum mass, which is relevant in the design of structurally complex electromechanical aviation systems.
The data processing problem in attitude and heading reference system based on two units of micromechanical gyroscopes is considered as a special class of information processing problems from two ...measurement sources. A novel algorithm used for processing the measurements data from two units of micromechanical gyroscopes is proposed, which can improve orientation system performance while reducing the requirements for external sensors. A mathematical error model of micromechanical gyroscopes and orientation system is given, considering the rotation of the measurement units, and the advantages of the proposed method is analyzed in comparison with other algorithms.
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