The article is in honor of the 80th birthday of Leonid P. Nesenyuk (1940-2009), Doctor of Technical Sciences, Professor, the Winner of the Russian Government Prize, Laureate of the N.N. Ostryakov ...Prize, the scientist who has made a significant contribution to the development of modern gyroscopy.
In the first part of the paper, a polynomial filter has been proposed for filtering under quadratic nonlinearities both in the system and measurement equations. The second part details its features ...and advantages over the extended Kalman filter and illustrates them using a methodological example and examples of navigation data processing.
Realistic mathematical models of physical processes contain uncertainties. These models are often described by stochastic differential equations (SDEs) or stochastic partial differential equations ...(SPDEs) with multiplicative noise. The uncertainties in the right-hand side or the coefficients are represented as random fields. To solve a given SPDE numerically one has to discretise the deterministic operator as well as the stochastic fields. The total dimension of the SPDE is the product of the dimensions of the deterministic part and the stochastic part. To approximate random fields with as few random variables as possible, but still retaining the essential information, the Karhunen–Loève expansion (KLE) becomes important. The KLE of a random field requires the solution of a large eigenvalue problem. Usually it is solved by a Krylov subspace method with a sparse matrix approximation. We demonstrate the use of sparse hierarchical matrix techniques for this. A log-linear computational cost of the matrix-vector product and a log-linear storage requirement yield an efficient and fast discretisation of the random fields presented.
This paper presents the results of a study of the time resolution of the scintillation elements of a detector designed to measure the absolute luminosity at the interaction points at the MPD ...experiment at NICA, Joint Institute for Nuclear Research (JINR) 1. The measurements are carried out using cosmic rays. The correspondence of time resolution to the problems of measuring luminosity is discussed here. It is shown that the time resolution is consistent with the concept of the detector and ensures the measurement of the absolute luminosity, as well as the study of the beam longitudinal profile.
The paper considers the filtering problems solved in navigation data processing under quadratic nonlinearities both in system and measurement equations. A Kalman type recursive algorithm is proposed, ...where the predicted estimate and gain at each step are calculated based on the assumption on the Gaussian posterior probability density function of the estimated vector at the previous step and minimization of estimation error covariance matrices using a linear procedure with respect to the current measurement. The similarities between this algorithm and other Kalman type algorithms such as extended and second-order Kalman filters are discussed. The procedure for evaluating the performance and comparing the algorithms is presented.
Luminosity Measurement and Control at NICA Igamkulov, Z.; Cruceru, M.; Kurepin, A. B. ...
Physics of particles and nuclei letters,
11/2019, Letnik:
16, Številka:
6
Journal Article
Recenzirano
A detector for measuring the luminosity at beam crossing points at the NICA collider is proposed. This small detector is based on scintillation counters and may be used both independently and as part ...of the base NICA detectors. Estimates of the count rate demonstrate that the number of useful counts per minute exceeds 10
4
for
pp
and Au–Au collisions. A detector calibration algorithm based on van der Meer scans is also proposed. Such calibration measurements take no more than 1 h at NICA. The distribution of interaction vertices is calculated for the NICA parameters.
We study the solvability of an inhomogeneous mixed boundary value problem for a stationary reaction-convection-diffusion model. Such models are often used in science and engineering for the ...description and analysis of various processes of heat and mass transfer. We focus on the issues of solvability of the boundary value problem in different functional spaces and on the stability of the solution and its continuous dependence on the input data in natural metrics. The peculiarity of the problem consists in the inhomogeneity and irregularity of the mixed boundary data. These boundary data, in general, cannot be continued inside the domain so that the continuation is sufficiently smooth and can be used in the known way to transform the problem to a problem with homogeneous boundary data. To prove the solvability of the problem, we use the Lax-Milgram theorem. Estimates for the norms of the solution follow from the same theorem. The cases where the solution operator is completely continuous are also established. The properties of the solution of the direct problem found in this study will be used later to solve inverse problems.
The paper presents a study of the chaotic jerk circuit (CJC) employment capabilities for digital communications. The concept of coherent chaos shift keying (CSK) communication system with controlled ...error feedback chaotic synchronization is proposed for a specific CJC in two modifications. The stability of chaotic synchronization between the two CJCs was evaluated in terms of voltage drop at the input of the slave circuit and the impact of channel noise using simulations and experimental studies.
A control system for the orbital electric drive of a press coupler capable of reducing energy consumption is considered. Because the stator is not completely overlapped by rotors, it is proposed to ...reduce the power consumption by means of turning off the power supply from the unused part of the rotor. This requires use of a rotor-positioning sensor as well as an algorithm for determining the overlap area depending on the position of the rotors. A calculation algorithm, which can be applied to orbital electric drives of different configurations, is presented. The algorithm creates rotor and stator maps depending on the angle and the sought overlap area is obtained by overlapping one map on another. This allows applying the optimization methods for finding an optimal control algorithm.
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