integral methods
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Actuators ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Fahimeh Shiravani ◽  
Patxi Alkorta ◽  
Jose Antonio Cortajarena ◽  
Oscar Barambones

In this paper, an enhanced Integral Sliding Mode Control (ISMC) for mechanical speed of an Induction Motor (IM) is presented and experimentally validated. The design of the proposed controller has been done in the d-q synchronous reference frame and indirect Field Oriented Control (FOC). Global asymptotic speed tracking in the presence of model uncertainties and load torque variations has been guaranteed by using an enhanced ISMC surface. Moreover, this controller provides a faster speed convergence rate compared to the conventional ISMC and the Proportional Integral methods, and it eliminates the steady-state error. Furthermore, the chattering phenomenon is reduced by using a switching sigmoid function. The stability of the proposed controller under parameter uncertainties and load disturbances has been provided by using the Lyapunov stability theory. Finally, the performance of this control method is verified through numerical simulations and experimental tests, getting fast dynamics and good robustness for IM drives.


2022 ◽  
Vol 20 (8) ◽  
pp. 3093
Author(s):  
E. A. Shmidt ◽  
S. A. Berns ◽  
T. Yu. Penskaya ◽  
I. I. Zhidkova ◽  
O. V. Gruzdeva ◽  
...  

Aim. To study the blood coagulation status by various laboratory methods in patients after pulmonary embolism (PE) receiving long-term anticoagulant therapy.Material and methods. The blood of 23 patients with pulmonary embolism, who received long-term anticoagulant therapy, was studied. The study of coagulation profile, D-dimer, thrombodynamics, thromboelastography and thrombin generation test were carried out.Results. The thrombin generation test shows a significant increase in the time of its formation, while the maximum amount of thrombin formed is half that of the reference values. There is a slightly increased median fibrin clot growth rate in the thrombodynamics test — 30,4 gm/min with a normal coagulation rate of 20-29 gm/min. The result of thromboelastography also reflects the blood hypocoagulation, in terms of R, Angle a and CI.Conclusion. Integral methods for assessing the thrombotic readiness in combination with a routine coagulation panel demonstrate a complete picture of blood coagulation potential in patients after pulmonary embolism requiring long-term anticoagulant therapy.


Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 124
Author(s):  
Rostislav Streletskii ◽  
Angelika Astaykina ◽  
George Krasnov ◽  
Victor Gorbatov

Experiments were carried out in soil microcosms with the treatment of pesticide formulations—imidacloprid, benomyl, and metribuzin in single and tenfold application rates. For additional stimulation of microorganisms, a starch–mineral mixture was added to some variants. For all samples, high-throughput sequencing on the Illumina MiSeq platform of the V4 (16S rRNA) and ITS1 (18S rRNA) fragments was carried out. As a result, it was possible to establish the characteristic changes in the structure of the soil fungal and bacterial communities under pesticides application. The application of pesticides was accompanied by dramatic shifts in alfa-diversity of the fungal community. The phylum Basidiomycota was likely to be involved in the degradation of pesticides. The changes in the relative abundance of the genera Terrabacter, Kitasatospora, Streptomyces, Sphingomonas, Apiotrichum, Solicoccozyma, Gamsia, and Humicola can be proposed as an indicator of pesticide contamination. It is suggested to use these markers for large-scale assessment of the effect of pesticides on soil microbial communities instead of classical integral methods, including within the framework of state registration of pesticides. It is also recommended to research the effect of pesticides on the soil microbiome during artificially initiated successions using the additional source of carbon.


Safety ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 84
Author(s):  
Kwang Hyun Im ◽  
Woongyi Kim ◽  
Seock-Jin Hong

This research aims to help develop aviation safety policies for the general aviation industry, especially for flight training schools. The analytical hierarchy process (AHP), fuzzy AHP, and fuzzy integral methods were used to find variables that impact aviation safety for training pilots in Korea and the United States using survey participants’ experience and perceptions. The results represent the circumstances of aviation safety in the real world where single pilot resource management, especially situational awareness, is crucial. The authors find that integral fuzzy AHP provides more explicit considerations, making up for the ambiguity of the linguistic responses caused by the AHP and fuzzy AHP.


2021 ◽  
Vol 63 ◽  
pp. 269-307
Author(s):  
Liam C. Morrow ◽  
Timothy J. Moroney ◽  
Michael C. Dallaston ◽  
Scott W. McCue

The classical model for studying one-phase Hele-Shaw flows is based on a highly nonlinear moving boundary problem with the fluid velocity related to pressure gradients via a Darcy-type law. In a standard configuration with the Hele-Shaw cell made up of two flat stationary plates, the pressure is harmonic. Therefore, conformal mapping techniques and boundary integral methods can be readily applied to study the key interfacial dynamics, including the Saffman–Taylor instability and viscous fingering patterns. As well as providing a brief review of these key issues, we present a flexible numerical scheme for studying both the standard and nonstandard Hele-Shaw flows. Our method consists of using a modified finite-difference stencil in conjunction with the level-set method to solve the governing equation for pressure on complicated domains and track the location of the moving boundary. Simulations show that our method is capable of reproducing the distinctive morphological features of the Saffman–Taylor instability on a uniform computational grid. By making straightforward adjustments, we show how our scheme can easily be adapted to solve for a wide variety of nonstandard configurations, including cases where the gap between the plates is linearly tapered, the plates are separated in time, and the entire Hele-Shaw cell is rotated at a given angular velocity.   doi:10.1017/S144618112100033X


2021 ◽  
pp. 110862
Author(s):  
J. Andrew Spencer ◽  
Brett Adair ◽  
Eric D. Held ◽  
Jeong-Young Ji ◽  
Joseph R. Jepson

2021 ◽  
Vol 89 (1) ◽  
Author(s):  
Nicola Guglielmi ◽  
María López-Fernández ◽  
Mattia Manucci

AbstractWe generalize ideas in the recent literature and develop new ones in order to propose a general class of contour integral methods for linear convection–diffusion PDEs and in particular for those arising in finance. These methods aim to provide a numerical approximation of the solution by computing its inverse Laplace transform. The choice of the integration contour is determined by the computation of a few suitably weighted pseudo-spectral level sets of the leading operator of the equation. Parabolic and hyperbolic profiles proposed in the literature are investigated and compared to the elliptic contour originally proposed by Guglielmi, López-Fernández and Nino 2020, see Guglielmi et al. (Math Comput 89:1161–1191, 2020). In summary, the article provides a comparison among three different integration profiles; proposes a new fast pseudospectral roaming method; optimizes the selection of time windows on which one may arbitrarily approximate the solution by no extra computational cost with respect to the case of a fixed time instant; focuses extensively on computational aspects and it is the reference of the MATLAB code [20], where all algorithms described here are implemented.


2021 ◽  
Vol 13 (3) ◽  
pp. 401-428
Author(s):  
Oleh Masliy ◽  
Ievgeniia Ivanchenko ◽  
Viacheslav Deriuhin ◽  
Viktor Olekhnovych ◽  
Serhii Yaniuk

Logistics readiness is an essential characteristic of future officers of army support units (forces) as it is required for planning and organization of processes and events of people movement, vehicles, equipment and ammunition supplies to the battlefield and military formation redeployment in any position in the shortest term. The purpose of the article is to explain the structure of logistics readiness of future officers of army support units (forces) and to identify its significant components taking into consideration general logistics sustainability of future logistics officers. According to the research, logistics sustainability is the resultant complex consisting of basic qualities and abilities that are professionally important for military logistics sphere. Also, we have explained the implementation of organizational and pedagogical conditions for formation of integral competence of future officers of army support units (forces). To achieve the purpose, the following methods were used: theoretical methods (general scientific methods, partially scientific methods, methods of intersubject research, deductive and inductive methods, generalization of best foreign pedagogical practices, comparative analysis, combination of integral methods, analysis of bibliographical sources, pedagogical forecast and planning methods, classification, formalization and theoretical interpretation methods) and empirical methods (discussions, direct and indirect observation, pedagogical monitoring, self-observation, interviewing, testing, method of expert estimations, self-assessment, pedagogical experiment). The study involved 120 cadets of the Military Academy (Odesa) and 36 experts (officers of logistics units of Operational Command «South» and instructors of the Military Academy (Odesa)) to estimate the qualities and abilities that are professionally important for future logistics officers. As a result, it was found that logistics readiness, which covers all the necessary qualities and abilities, is the basis for integral competence of future officers of army support units (forces) and it is formed in the process of studying at the higher military educational establishment.


Author(s):  
Sundar Namala ◽  
Rizwan Uddin

Abstract Nodal integral methods (NIM) are a class of efficient coarse mesh methods that use transverse averaging to reduce the governing partial differential equation(s) (PDE) into a set of ordinary differential equations (ODE). The standard application of NIM is restricted to domains that have boundaries parallel to one of the coordinate axes/palnes (in 2D/3D). The hybrid nodal-integral/finite-element method (NI-FEM) reported here has been developed to extend the application of NIM to arbitrary domains. NI-FEM is based on the idea that the interior region and the regions with boundaries parallel to the coordinate axes (2D) or coordinate planes (3D) can be solved using NIM, and the rest of the domain can be discretized and solved using FEM. The crux of the hybrid NI-FEM is in developing interfacial conditions at the common interfaces between the NIM regions and FEM regions. We here report the development of hybrid NI-FEM for the time-dependent convection-diffusion equation (CDE) in arbitrary domains. Resulting hybrid numerical scheme is implemented in a parallel framework in Fortran and solved using PETSc. The preliminary approach to domain decomposition is also discussed. Numerical solutions are compared with exact solutions, and the scheme is shown to be second order accurate in both space and time. The order of approximations used for the development of the scheme are also shown to be second order. The hybrid method is more efficient compared to standalone conventional numerical schemes like FEM.


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