The statistical maximum likelihood (EM) method and the algebraic reconstruction method with simultaneous iterations (SART) are two methods of iterative tomographic reconstruction. These algorithms are often used when the projection data contains a large amount of statistical noise or has been obtained from a limited range of angles. One of the popular approaches used to increase the rate of convergence of these algorithms is to perform a correction of the current approximation of the reconstructed object on subsets of the projection data. The desire to increase the convergence rate of the iterative methods led to the use of ordered subsets of projections for both the maximum likelihood method of EM (OS-EM) and for the algebraic reconstruction method with simultaneous iterations of SART (OS-SART). The efficiency of using ordered subsets of projections was first established for sequential programs that run on the central processor of the computer (CPU). In this work, both these methods have been accelerated by using the OpenGL graphics library by mirroring them on the graphics processor architecture of the video card.

Approaches evolution and concept of data accumulation in warehouse and subsequent Data Mining use is perspective due to the fact that, Belarusian segment of the same IT-developments is organizing. The article describes the general concept for creation a system of storage and practice-oriented data analysis, based on the data warehousing technology. The main aspect in universal system design on storage layer and working with data is approach uses extended data warehouse, based on universal platform of stored data, which grants access to storage and subsequent data analysis different structure and subject domains have compound’s points (nodes) and extended functional with data structure choice option for data storage and subsequent intrasystem integration. Describe the universal system general architecture of storage and analysis practice-oriented data, structural elements. Main components of universal system for storage and processing practice-oriented data are: online data sources, ETL-process, data warehouse, subsystem of analysis, users. An important place in the system is analytical processing of data, information search, document’s storage and providing a software interface for accessing the functionality of the system from the outside. An universal system based on describing concept will allow collection information of different subject domains, get analytical summaries, do data processing and apply appropriate Data Mining methods and algorithms.

The article discusses the expansion of the previously formulated approach to modeling aspects of the reproductive cycle, taking into account the changes in the habitat and metamorphosis in the development of fish. Excessive accumulation of nutrients with prolonged use of a reservoir for artificial growth of juveniles or accelerated decomposition of organic nitrogen and phosphorus may in some cases affect the success of the reproductive process. This creates an indirect effect on long-term trends in population dynamics. In some cases, the increase in the influx of organic phosphorus further leads to a state of eutrophication and may affect the insufficient aeration of breeding sites, leading to hypoxia for hatched larvae. Even worsen the situation with the consumption of oxygen in the water at the mass destruction of eggs. Lack of organic matter leads to insufficient development of planktonic organisms for optimal growth of fishes. The system of survivability equations for calculation competing individuals of the generation is supplemented by a functional extension using an iterative model of biogenic elements dynamics, based on the analysis of processes in the ecosystem of Lake Chao. The block of the model for calculating the inflow and destruction of organic matter is synchronized with a continuous-discrete computational structure that takes into account the interrelated changes in mortality factors and the rate of development of juvenile fish during transitions between generalized ecological and physiological stages of development.

In this article an extended literature surveying review is launched on a set of comparative studies of maximum power point tracking (MPPT) techniques. Different MPPT methods are addressed with an ultimate aim of how to be maximizing the PV system output power by tracking Pmax in a set of different operational circumstances. In this paper maximum power point tracking, MPPT techniques are reviewed on basis of different parameters related to the design simplicity and/or complexity, implementation, hardware required, and other related aspects.

he technology of solar systems has been booming for a while due to its ability to replace current fossil fuels like coal and gas for generation of electricity that produce air, water, and land pollution. In addition it decreased the issue of global warming and climate changes substantially due to being produced in a clean environmental manner and was proved to be an Eco-friendly resource of energy. The photovoltaic systems’ manufacturing process has been improving continuously over the last decade and photovoltaic systems have become an interesting solution. Precisely, PV systems are constituted from arrays of photovoltaic cells, choppers (mainly buck-boost or boost DC/DC converter), MPPT control systems and storage devices and/or grid connections. To improve the efficiency of such systems, various studies have been performed. The demand of PV generation systems seems to be increased for both standalone and grid-connected modes of PV systems. Therefore, an efficient maximum power point tracking (MPPT) technique is necessary to initialize the process of tracking the maximum power point MPP at all environmental conditions and then force the PV system to operate at that MPP point.

The problem of parametric identification of a mathematical model of a technical system or a device is considered, which considers the electric drive of a monitoring system installed on an unmanned aerial vehicle. Identification of the parameters of elements of a complex technical system is an actual scientific task, since when developing a new technical system for its synthesis and research, it is necessary to have mathematical models of the elements of the system.

It is proposed to solve the problem by applying the search gradient identification algorithm for a given objective residual function in the form of a difference in the output signal of the identified element of the system and its model. When solving the problem, the random character of the processes occurring in the system and at the output of the output signal meter is taken into account. The identification algorithm is developed on the basis of the representation of the model of parameters in the form of an ordinary vector-matrix equation, on the right side of which there is a model of the driving influence in the form of a given deterministic function of time. A general structural diagram of the parametric identification search system with a gradient algorithm is presented.

As an example for evaluating the operability of the proposed algorithm, we consider the simplest model of an electric drive, given by a transfer function in the form of an inertial link. Qualitative illustrations of the operability of the proposed algorithm and quantitative characteristics of the signal and parameter changes of the identified object are presented.

The problem of differences identifying in vector graphics data packages and how to solve it is considered. Map information and vectorized data of remote sensing of Earth are sources of vector data in the article. The aim is to design a method for detecting differences in vector data packages, providing reliable results for updating map and monitoring areas tasks. Research and development is done by mathematical modeling of the task in MATLAB. The article provides developed method for solving the task and results of its application for finding differences between two vector data packages, obtained from the target information of remote sensing of the Earth, and/or vector layers of digital district map. This method allows you to automate the process and reduce the time of thematic analysis of cosmic information, obtained from remote sensing of the Earth for topographic mapping and monitoring areas.

A new hashing algorithm based on dynamic chaos is proposed. Owing to the use of chaotic mappings, this algorithm is irreversible and a search for two messages with identical hash-values becomes computationally difficult. The proposed algorithm consists of the stages: selection of the variables and of the parameters of two-dimensional chaotic mappings; realization of iterations of the chaotic mappings with the addition of the original-message elements to the variables; realization of iterations of the chaotic mappings without the addition of the original-message elements to the variables; the hash-value formation. The formation of the two hash-values h1 and h2realized with different orders of the variables. The resultant hash-value is obtained by the modulo-2 addition operation applied to the hash-values h1 and h2. The proposed algorithm has been tested. It has been found that this algorithm is characterized by the avalanche effect. The statistical characteristics of the sequence formed of hash-values are identical to those of the sequence with the randomly obtained values of the elements, pointing to the adequate performance of this algorithm. The computational experiment has been realized using the Chirikov, «Arnold’s cat» and Henon maps. It is demonstrated that, with the use of Henon and «Arnold’s cat» maps for the messages exceeding 4 KB, the proposed algorithm outperforms «Keccak» algorithm, being faster by 20% and more.

The proposed hashing algorithm may be used in solving the problems of data integrity in modern telecommunication systems.

The article deals with the linguistic database for the system of automatic generation of English advertising texts on cosmetics and perfumery. The database for such a system includes two main blocks: automatic dictionary (that contains semantic and morphological information for each word), and semantic-syntactical formulas of the texts in a special formal language SEMSINT. The database is built on the result of the analysis of 30 English advertising texts on cosmetics and perfumery. First, each word was given a unique code. For example, N stands for nouns, A – for adjectives, V – for verbs, etc. Then all the lexicon of the analyzed texts was distributed into different semantic categories. According to this semantic classification each word was given a special semantic code. For example, the record N01 that is attributed to the word «lip» in the dictionary means that this word refers to nouns of the semantic category «part of a human’s body».

The second block of the database includes the semantic-syntactical formulas of the analyzed advertising texts written in a special formal language SEMSINT. The author gives a brief description of this language, presenting its essence and structure. Also, an example of one formalized advertising text in SEMSINT is provided.