Calculation of rainfall from satellite data in and around Bangladesh

We calculated GMS Precipitation Index (GPI, satellite rainfall) using three hourly IR data from GMS-5 over Bangladesh and adjoining areas for spatial resolution of 0.5° × 0.5°, l° × 1°, 2° × 2° and temporal scales of 1-day, 3-day and 7-day and monthly averages. There was no special difference between the spatial averaging scale of 0.5° or 1° mesh on land. The GPI contours were closely spaced in 0.5° mesh and better to comprehend the GPI fluctuation. From the monsoon month of June to July the GPI maxima and minima shift from their original (starting) location. Both the GPI maxima and minima shifted toward north. There was an increase in GPI as one moved from north to south. Sea and offshore areas received almost uniform GPI compared to land areas where rain fluctuations occurred with little horizontal distance. It was found that actual rainfall was 88% of the GPI in this study.

Parallelization of Finding the Current Coordinates of the Lidar Based on the Genetic Algorithm and OpenMP Technology

The problem of determining the position of the lidar with optimal accuracy is relevant in various fields of application. This is an important task of robotics that is widely used as a model when planning the route of vehicles, flight control systems, navigation systems, machine learning, and managing economic efficiency, a study of land degradation processes, planning and control of agricultural production stages, land inventory to evaluations of the consequences of various environmental impacts. The paper provides a detailed analysis of the proposed parallelization algorithm for solving the problem of determining the current position of the lidar. To optimize the computing process in order to accelerate and have the possibility of obtaining a real-time result, the OpenMP parallel computing technology is used. It is also possible to significantly reduce the computational complexity of the successive variant. A number of numerical experiments on the multi-core architecture of modern computers have been carried out. As a result, it was possible to accelerate the computing process about eight times and achieve an efficiency of 0.97. It is shown that a special difference in time of execution of a sequential and parallel algorithm manages to increase the number of measurements of lidar and iterations, which is relevant in simulating various problems of robotics. The obtained results can be substantially improved by selecting a computing system where the number of cores is more than eight. The main areas of application of the developed method are described, its shortcomings and prospects for further research are provided.

Two Stage Implicit Method on Hexagonal Grids for Approximating the First Derivatives of the Solution to the Heat Equation

The first type of boundary value problem for the heat equation on a rectangle is considered. We propose a two stage implicit method for the approximation of the first order derivatives of the solution with respect to the spatial variables. To approximate the solution at the first stage, the unconditionally stable two layer implicit method on hexagonal grids given by Buranay and Arshad in 2020 is used which converges with Oh2+τ2 of accuracy on the grids. Here, h and 32h are the step sizes in space variables x1 and x2, respectively and τ is the step size in time. At the second stage, we propose special difference boundary value problems on hexagonal grids for the approximation of first derivatives with respect to spatial variables of which the boundary conditions are defined by using the obtained solution from the first stage. It is proved that the given schemes in the difference problems are unconditionally stable. Further, for r=ωτh2≤37, uniform convergence of the solution of the constructed special difference boundary value problems to the corresponding exact derivatives on hexagonal grids with order Oh2+τ2 is shown. Finally, the method is applied on a test problem and the numerical results are presented through tables and figures.

Well-Designed Termination Wall of Perfectly Matched Layers for ATS-FDTD Method

This paper presents a well-designed termination wall for the perfectly matched layers (PML). This termination wall is derived from Mur’s absorbing boundary condition (ABC) with special difference schemes. Numerical experiments illustrate that PML and the termination wall works well with ATS-FDTD(Shi et al. 2015). With the help of termination wall, perfectly matched layers can be decreased to two layers only; meanwhile, the reflection error still reaches -60[dB] when complex waveguide is simulated by ATS-FDTD.

Electrodynamic method in bistatic radar - real and artificial targets

The research shows that the real aerial weapon, i.e. hypersonic missile warhead and the target simulator of the MALD type, in bistatic radar result in significantly different topological scattering patterns when taking into account the radiation polarization. Radiation with p -polarization allows for a more expressive topological scattering pattern than in the case of s -polarization, and the θ angle change of the place gives a brighter relief pattern with alternating maxima and deep minima, which leads to an assumption about a high resolving power when identifying the objects by means of the gradient method. A special difference between the two objects, i.e. the target simulator and the missile warhead, can be observed in the case of s -polarization: the patterns differ significantly in topology, the missile maxima regions occupy a larger area, while the minima are much deeper

Estimating a special difference of harmonic numbers

The aim of this paper is to investigate a special difference of harmonic numbers. We obtain some limits and inequalities involving harmonic numbers and in the last part of the paper some open problems for investigation are posed.

Clinical and morphological characteristics of chronic endometritis in women with hysteromyoma

The aim of our research was to identify clinical, morphological features of chronic endometritis among women of reproductive age with a hysteromyoma. 150 patients of reproductive age were surveyed. After which women were divided into three groups. The first group consisted of women at whom the hysteromyoma was combined with a chronic endometritis. The second group - chronic endometritis without hysteromyoma. The third group consisted of apparently healthy women who have addressed to the doctor with questions of contraception and pregnancy planning. It is established that the clinical and morphological picture of a chronic endometritis doesn’t depend on existence at such women of a hysteromyoma. At the women surveyed in both the first and second group almost equally often found inflammatory diseases of the pelvic organs, the bottom department of the genitals, hyperplastic process of endometrium, abnormal uterine bleeding. Special difference in activity of inflammatory process in an endometriya depending on the availability at these women hysteromyoma is not revealed. The combination of chronic endometritis with hysteromyoma is more common for women of late reproductive age, in the anamnesis whicht had childbirth, induced abortion.

NEW METHOD FOR CHARACTERISTIC EVOLUTIONS IN NUMERICAL RELATIVITY

The main task of numerical relativity is to solve Einstein equations with the aid of supercomputer. There are two main schemes to write Einstein equations explicitly as differential equations. One is based on 3 + 1 decomposition and reduces the Einstein equations to a Cauchy problem. The another takes the advantage of the characteristic property of Einstein equations and reduces them to a set of ordinary differential equations. The latter scheme is called characteristic formalism which is free of constraint equations in contrast to the corresponding Cauchy problem. Till now there is only one well developed code (PITT code) for characteristic formalism. In PITT code, special finite difference algorithm is adopted for the numerical calculation. And it is this special difference algorithm that restricts the numerical accuracy order to second-order. In addition, this special difference algorithm makes the popular Runge–Kutta method used in Cauchy problem not available. In this paper, we modify the equations for characteristic formalism. Based on our new set of equations, we can use usual finite difference method as done in usual Cauchy evolution. And Runge–Kutta method can also be adopted naturally. We develop a set of code in the framework of AMSS-NCKU code based on our new method and some numerical tests are done.