Journal of Technical Science and Technologies

The Methodology of Teaching Algorithms of Combinatorics: Permutations, Combinations, Arrangements

2020-05-05T14:09:28+04:00

In this article we have described the methodology for teaching the algorithms of combinatorics which are often used when solving tasks of informatics. These are the economic types of tasks in which we need to select different objects, sort selected objects in some order and choose the best selection from all possible selections. The formulas of calculating number of such selections are known from mathematics, but in informatics we are interested not only in number, but also in selections themselves, which can be generated by special algorithms. In general, the number of such selections is quite large, so we need to use optimal algorithms to find the desired answer in real time. The essence of combinatoric objects is explained. It is shown how to find the desired object in optimal way. The samples and description of the corresponding algorithms are presented using the programming language C ++.

Keywords: Combinatorics, Methodology, Permutations, Combinations, Arrangements, Combinatorial object, Selections

About One NoSQL Mechanism For Accessing Panel Data

2020-05-05T14:16:20+04:00

In the presented paper, the problems connected with the support of the life cycle of information resource represented by panel data are considered. An example of a logical markup of a statistical document emerged at the stage of information resource planning is given, as well as a relational formalism describing the structure of the statistical table included in the document. Examples of NoSQL statements for data manipulation and processing, based on this relational formalism are presented. The problem of building a cyber infrastructure intended for the accumulation and distribution of an analytical information resource is discussed.

Keywords: Panel data; Information resource lifecycle; Multidimensional data model. Relational formalism; NoSQL mechanism

An algorithm of Simulation of Set of Random Variables with Predefined Correlation Structure

2020-05-05T14:26:33+04:00

Aricle is dedicated to the problem of generation of simulated data under the predefined internal correlation structure. Methodology is based on Gram Smith orthogonalization process and Cholesky decomposition of special type of positive definite symmetric matrices. All necessary steps with programming implementation are presented.At the end of article, tables of results of simulated data is presented and programming codes is also appended in appendix parts

Keywords: Cholesky Decomposition, Gram-Smith Orthogonalization, Positive Definiteness

Relative Thermal Stability of Α- and Β-Modifications of Ge3n4

2020-05-05T14:39:41+04:00

In this article the processes occurring when heating pure α-, β-Ge3N4 and their mixtures in a low dynamic vacuum, as well as in hydrogen and water vapor are discussed. Relative thermal stability of pure α- and β-modifications of Ge3N4 and their mixtures is studied. In vacuum α-Ge3N4
dissociates at temperatures of T ≥ 740°C, and β-Ge3N4 at T ≥ 780°C. At lower temperatures both modifications are sublimated. Sublimation heat of α-Ge3N4 is ~245 kJ/mol, and of β-Ge3N4 is ~290 kJ/mol. The predominant thermal stability of β-Ge3N4 is also evident in hydrogen and water vapor media.

Keywords: Germanium nitride, α-Ge3N4, β-Ge3N4, thermal stability, sublimation dissociation.

Analysis of Correction in Automatic Control Systems with Root Locus

2020-05-05T14:44:35+04:00

The article addresses the major challenges of automated control systems and solutions. One way is to choose the appropriate correction for the system and analyze parameters. For the synthesis of corrective device parameters, the article uses the root locus method.Root locus can be constructed by changing one or more parameter, which allows a thorough analysis of the stability of the system.In article one of the types the integrating corrective scheme with r, L, C source of an input signal is considered. The problem of synthesis of parameters of an integrated corrective scheme with root locus is is solved; The root locus is constructed, and with their help, the possibility of the approach of roots of the characteristic equation, to roots of the ideal transfer function is considered.

Keywords: Control systems, automatic control system, correction, root locus, synthesis parameters.