The problem of developing universal classifiers of biomedical data, in particular those that characterize the presence of a large number of parameters, inaccuracies and uncertainty, is urgent. Many studies are aimed at developing methods for analyzing these data, among them there are methods based on a neural network (NN) in the form of a multilayer perceptron (MP) using GA. The question of the application of evolutionary algorithms (EA) for setting up and learning the neural network is considered. Theories of neural networks, genetic algorithms (GA) and decision trees intersect and penetrate each other, new developed neural networks and their applications constantly appear. An example of a problem that is solved using EA algorithms is considered. Its goal is to develop and research a classifier for the diagnosis of breast cancer, obtained by combining the capabilities of the multilayer perceptron using the genetic algorithm (GA) and the CART decision tree. The possibility of improving the classifiers of biomedical data in the form of NN based on GA by applying the process of appropriate preparation of biomedical data using the CART decision tree has been established. The obtained results of the study indicate that these classifiers show the highest efficiency on the set of learning and with the minimum reduction of Decision Trees; increasing the number of contractions usually degrades the simulation result. On two datasets on the test set, the simulation accuracy was - 83 - 87 %. The experiments carried out have confirmed the effectiveness of the proposed method for the synthesis of neural networks and make it possible to recommend it for practical use in processing data sets for further diagnostics, prediction, or pattern recognition.

This paper describes the architecture and components of the distributed information and management system for collecting, processing, storing, and distributing data on a radiometric and dosimetric experiment using the principle of the Internet of Things. Data exchange between elements in the system, as well as the analysis of the received information, involves active application of the ThingSpeak cloud service. Two-way communication with the cloud with a 15-second loop has been implemented. Data are processed in the MATLAB (America) environment, integrated into the cloud. The developed hardware and software solutions demonstrate an increased accuracy of measurements due to the use of promising cadmium telluride (CdZnTe) detectors, modern microcontroller and micro communication technology, and a new algorithm for correcting the dependence of detector sensitivity on radiation energy. Measurement with correction by the method of average charge pulse amplitude is carried out in the energy range from 60 keV to 3 MeV. The resolution of the spectrometric channel is 6,5 % at the peak of 662 keV of full absorption from the reference source, Cesium (Cs-137). The module for a laboratory sensor network, designed to measure the dose of ionizing radiation, has a built-in spectrometric analog-digital converter, microcontroller control, and a communication unit. Constructing the diagrams demonstrates the operation of the interrupt handler in the form of a series of events occurring when requests arrive from a Web server. The peculiarity of the system is the absence of intermediate devices that make it possible to establish a connection with the Internet. The developed system, equipment, algorithms, and programs are used for experimental studies of radiation and nuclear-physical processes. Elements of the system were useful for remote laboratory work by students.

The quality characteristics of raw water sources in the regional integrated drinking water supply system (SPAM) of Banjarbakula were investigated and found to maintain the supply of drinking water quantity and quality in accordance with drinking water standards. The optimum model for the mixing process of raw water and poly aluminum chloride (PAC) and pump stroke for the input of water sources from rivers to obtain a composition setting that is in accordance with the raw water sources of each region in the region was selected and determined. So the optimum parameter setting model between alum water, raw water and pump stroke for each raw water source is known and is regionally integrated as a result of a comprehensive study. The integration of Taguchi parameter design and response surface can complement each other and become two methods that go hand in hand in the process of optimizing clean water products. Parameter design provides a very practical optimization step, the basis for this formation refers to the factorial fractional experimental design. However, the absence of statistical assumptions that follow the stages of analysis makes this method widely chosen by researchers and practitioners. With the experimental design of the raw water mixing process, turbidity such as 5 lt/sec, 10 lt/sec, 15 lt/sec, 20 lt/sec and 25 lt/sec and % PAC concentration 5 ppm, 10 ppm, 15 ppm, 20 ppm and 25 ppm with a pump installation stroke of 5 %, 10 %, 15 %, 20 % and 25 % were used. In the process of adding PAC, always pay attention and observe the behavior of the attractive force of the floating particles (flock). The particles were then subjected to SEM (scanning electron microscopy) to determine the dimensions of the flock grains deposited.

Information security, reliability of data transfer are today an important component of the globalization of information technology. Therefore, the proposed work is devoted to highlighting the results of the design and development of a hacking-resistant algorithm to ensure the integrity of information transfer via digital technology and computer engineering. To solve such problems, cryptographic hashing functions are used. In particular, elements of deterministic Chaos were introduced into the developed cyclic hashing algorithm. The investigation analyzes in detail the strengths and weaknesses of known hashing algorithms. They are shown to have disadvantages. The main ones are a large number of matches (Hamming (x, y) and the presence of a weak avalanche effect, which lead to a significant decrease in the reliability of the algorithm for hacking. The designed hashing algorithm uses an iterative Merkley - Damgard structure, augmented by the input message to a length multiple of 512 bits. Processing in blocks of 128-bit uses cellular automata with mixed rules of 30, 105 and 90, 150 and takes into account the dependence of the generation of the initial vector on the incoming message. This allows half of the 10,000 pairs of arbitrary messages to have an inverse Hamming distance of 0 to 2. The proposed algorithm is four times slower than the well-known family of "secure hash algorithms." However, computation speed is not a critical requirement for a hash function. Decreasing the sensitivity to the avalanche effect allows the generation time to be approximately halved. Optimization of the algorithm, as well as its testing was carried out using new technologies of the Java programming language (version 15). Suggestions and recommendations for improving this approach to data hashing are given also.

A Software-Defined Network (SDN) on a Wide Area Network (WAN) is a computer network that is controlled and created by software. SD-WAN is an emerging research area that has received a lot of attention from industry and government. This technology offers tremendous opportunities to support the creation of consolidated data centers and secure networks. This is an innovation that allows the network to be monitored and programmed so that it can respond to network events caused by security breaches. This solution provides network security, offers a single network management console, and provides complete control over the network architecture. Also controls security in the cloud software-defined infrastructure (SDI), such as dynamically changing the network configuration when forwarding packets, blocking, redirecting, changing Media Access Control (MAC) or Internet Protocol (IP) addresses, limiting the packet flow rate etc. Using SD-WAN technology, it is possible to reduce the cost of dedicated bandwidth channels, achieve a high-quality Virtual Private Network (VPN), and the ability to automatically select a channel for certain channels. The main advantages of SD-WAN are the management of an unlimited number of devices from a single center, reducing the cost of deploying branch infrastructure. According to the results of the survey, 7 % of respondents use SD-WAN for security solutions, 14 % at the piloting stage. As a result of the research, it was revealed that by 2024, to increase the flexibility and support of cloud applications, more than 60 % of SD-WAN customers will implement the SASE (Secure Access Service Edge) architecture, which is 30 % more than in 2020 and the main concept - application security and cloud functions.

One of the directions to improve the efficiency of modern telecommunication systems is the transition to the use of multidimensional signals for continuous channels of information transmission. As a result of studies carried out in recent years, it has been established that it is possible to ensure high quality of information transmission in continuous channels by combining demodulation and decoding operations into a single procedure that involves the construction of a code construct for a multidimensional signal. This paper considers issues related to estimating the possibility to improve the efficiency of continuous information transmission channel by changing the signal distance of the code structure. It has been established that the code structures of such types as a hierarchical code construct of signals, a hierarchical code construct of signals with Euclidean metric, a reversible code construct of signals, a reversible code construct of signals with Euclidean metric have the potential, when used, to increase the speed of information transmission along a continuous channel. With a signal distance reduced by 10 percent or larger, it could increase by two times or faster. The estimation of the effect of reducing a signal distance on the efficiency of certain types of code structures was carried out. It has been established that the hierarchical reversible code construct, compared to the hierarchical code construct, provides a win of up to two or more times in the speed of information transmission with a halved signal distance. Implementing the modulation procedure has no fundamental difficulties, on the condition that for each code of the code construct the encoding procedure is known when using binary codes. The results reported here make it possible to build an acceptably complex demodulation procedure according to the specified types of code structures.

Індекс рубрикатора НБУВ: Д222.1

Рубрики:

Склад і властивості вод суші

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

This paper reports the analysis of the biological destruction of timber and the use of protective materials, which established that the scarcity of data to explain and describe the process of bioprotection, neglect of environmentally friendly agents lead to the biodegradation of timber structures under the action of microorganisms. Devising reliable methods for studying the conditions of timber protection leads to designing new types of protective materials and application technologies. Therefore, it becomes necessary to determine the conditions for the formation of a barrier for bacteria permeability and to establish a mechanism for inhibiting material biodegradation. Given this, the dependence has been derived to determine the proportion of destroyed material under the effect of microorganisms when using an antiseptic-hydrophobicizer, which makes it possible to evaluate biopenetration. Based on the experimental data and theoretical dependences, the share of destroyed timber was determined under the effect of microorganisms, which is equal to 1 for natural timber. At the same time, this value for thermally modified timber is 0,033, and, when it is protected with oil - 0,009, respectively, exposed to the action of microorganisms for 60 days. It should be noted that the presence of oil, wax, and azure leads to blocking the timber surface from penetration. Such a mechanism underlying the effect of protective coating is likely the factor in the process adjustment, due to which the integrity of the object is preserved. Thus, a polymer shell was created on the surface of the sample, significantly reducing the penetration of microorganisms inside the timber, while the loss of timber mass during biodestruction did not exceed 2,5 %. Therefore, there are grounds to assert the possibility of targeted control over the processes of timber bio-penetration by using coatings capable of forming a protective film on the surface of the material.

Індекс рубрикатора НБУВ: Л920.21-5

Рубрики:

Оброблення м’яса холодом

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

The British Retail Consortium Global Standard for Food Safety enjoys great popularity among food industry companies, the number of companies with the certified standard is rising every year. The packaging used for food packaging has a very large impact on the safety and quality of the packaged food. The purpose of the study was to indicate the requirements of the standard in relation to packaging, which should be implemented firstly by enterprises of the food industry. In the research part, the AHP analysis was conducted on the basis of the experts' recommendations. Decision matrixes for every criterion: hazard analysis concerning packaging, purchase procedure, packaging acceptance procedure were developed. A decision matrix for the main criterion as a result of criteria decision matrix was developed, global decision hierarchy was also developed. Research clearly showed that the most important activity (among the proposed) is hazard analysis, with a 0,517 weighted sum value. In many of the detailed requirements of the standard, hazard analysis and risk assessment (0,333 weighted sum value) are the basis for many activities, including establishing a purchasing procedure (0,163 weighted sum value), accepting packaging (0,297 weighted sum value), or many others. The relevance of this study is the identification of the hierarchy of importance of activities performed within the framework of ensuring the quality and safety of food packaging. A reasonable approach is presented. The AHP method allows indicating the sequence of activities during the implementation of the BRC standard, as evidenced by pilot studies carried out on the basis of procedures related to the safety of packaging. The standard sets up requirements for packaging in the form of packaging management procedure, in which it should be stated how the site operates with packaging. Moreover, there are requirements concerning hazard analysis in relation to packaging.

Індекс рубрикатора НБУВ: П60-45 + П60-6

Рубрики:

Велика рогата худоба

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: К641.3

Рубрики:

Газове зварювання металів

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

A self-adjusting zero-order Brown's model has been devised. This model makes it possible to predict with high accuracy not only fires in the premises but also irreversible processes and phenomena of a random and chaotic nature under actual conditions. The essence of the self-adjusting model is that, based on Kalman's approach, it is proposed to set the smoothing parameter for each time moment. Such a parameter is determined depending on the resulting current forecast error, taking into consideration the real and unknown dynamics of the studied series and noise. That does not require the selection of the smoothing parameter characteristic of known models. In addition, the proposed Brown's model, unlike the known modifications, does not require setting a dynamics model of the level of the examined time series. The self-adjusting model provides negligible errors and efficiency of the forecast. The operability of the devised model was checked using an example of the experimental time series for the current measure of the recurrence of the increments of the state of the air medium in the laboratory chamber during alcohol combustion. As quantitative indicators of the quality of the forecast error, the current values for the square and absolute values were considered. It has been established that the current square of the forecast error is more than six orders of magnitude smaller compared to the case of a fixed smoothing parameter from a beyond-the-limit set. However, the current square of the forecast error for abrupt changes in the dynamics of the series level is half that of the fixed parameter of the beyond-the-limit set. It is noted that the results confirm the feasibility of the proposed self-adjusting Brown's model.

AC steel arc furnaces are the most powerful units connected to the electrical grid, the operating mode of which is dynamic, asymmetrical and non-linear. That is why these furnaces cause the entire possible range of negative effects on the quality of electricity in the grid, in particular, fluctuations, asymmetry and non-sinusoidal voltage. Known proposals for improving the electromagnetic compatibility of electric arc furnaces are mainly focused on eliminating the consequences of their negative impact on the power grid. The proposed approach and the corresponding technical solution are aimed at reducing the level of generation of a negative factor and at the same time reduce fluctuations, asymmetry and non-sinusoidal voltage. This result is obtained due to the fact that the proposed solution takes into account the peculiarities of the range of modes natural for arc furnaces. Optimal for such consumers is the use of a constant current power supply system I = const in the range of modes from operational short circuit to maximum load and the system U = const in the whole other range of modes. The implementation of such a system is carried out on the basis of a resonant converter "constant current - constant voltage". Studies have found that the use of such a power supply system, in comparison with the traditional circuit, makes it possible to reduce the non-sinusoidal voltage in a low-power grid from 3,2 % to 2,1 % and the unbalance coefficient from 3,66 to 1,35 %. Previously published data on a significant reduction in voltage fluctuations was also confirmed. The positive effect of such a system on the energy performance of the furnace itself is shown, manifested in an increase in the arc power by 12,5 %, and the electrical efficiency by 5,1 %. This improves the productivity and efficiency of electric arc furnaces.

Індекс рубрикатора НБУВ: З261.8

Рубрики:

Трансформатори. Трансформаторобудування

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

An urgent scientific and practical problem is the formation of energy efficient systems for ensuring climatic conditions in premises based on the use of renewable energy sources. The work has improved the technical and methodological approach to the calculations of energy supply and storage systems when using energy-active fences. The special effectiveness of these fences has been shown in the transitional periods of the year, that is, in spring and autumn. A mathematical model has been developed to reliably predict the process of ensuring temperature comfortable conditions (heat balance) when using nonparametric statistics methods. It will improve the quality of forecasting the effect of external air temperature during the transitional periods of the year. The temperature inside the room is taken into account in the presence of a multilayer energy-active fence. To determine the approach to the use of heat in energy supply systems during the transition period, thermal parameters from the inner and outer sides of the building structure are considered. This makes it possible to take into account changes in the heat transfer of these structures when designing a power supply system and determining the optimal modes of its functioning in various natural conditions. The function of energy-active fences associated with the generation of additional heat into the system, obtained through the conversion of solar radiation energy, is considered. To increase this generation, special multilayer designs of energy-active fencing have been proposed. The proposed thermal modernization with the use of energy-active fences allows, on average, over the cold period of the year, to reduce energy consumption by 3,5 times for industrial and residential buildings.

This paper reports determining the energy efficiency of a vibratory machine consisting of a viscoelastically fixed platform that can move vertically, and a vibration exciter whose operation is based on the Sommerfeld effect. The body of the vibration exciter rotates at a steady angular speed while there are the same loads in the form of a ball, a roller, or a pendulum inside it. The load, being moved relative to the body, is exposed to the forces of viscous resistance, which are internal within the system. It was established that under the steady oscillatory modes of a vibratory machine's movement, the loads are tightly pressed to each other, thereby forming a combined load. Energy is productively spent on platform oscillations and unproductively dissipated due to the movement of the combined load relative to the body. With an increase in the speed of the body rotation, the increasing internal forces of viscous resistance bring the speed of rotation of the combined load closer to the resonance speed, and the amplitude of platform oscillations increases. However, the combined load, in this case, increasingly lags behind the body, which increases unproductive energy loss and decreases the efficiency of the vibratory machine. A purely resonant motion mode of the vibratory machine produces the maximum amplitude of platform oscillations, the dynamic factor, the total power of viscous resistance forces. In this case, the efficiency reaches its minimum value. To obtain vigorous oscillations of the platform with a simultaneous increase in the efficiency of the vibratory machine, it is necessary to reduce the forces of viscous resistance in supports with a simultaneous increase in the internal forces of viscous resistance. An algorithm for calculating the basic dynamic characteristics of the vibratory machine's oscillatory motion has been built, based on solving the problem parametrically. The accepted parameter is the angular speed at which a combined load gets stuck. The effectiveness of the algorithm has been illustrated using a specific example.

A method for determining effective elastic constants of a composite unidirectionally reinforced with two types of transtropic hollow fibers is developed. Determining these characteristics is an integral step in the design of composite structures. The approach is based on analytical formulas for determining the elastic characteristics of a two-component composite with a transtropic matrix and hollow fiber. Hexagonal fiber lay-up with periodic reinforcement structure is considered. Double homogenization is used. The composite is conventionally divided into hexagonal regions of two types. The first is a hollow fiber of one material and the surrounding matrix. Similarly, the second one - with a hollow fiber of another material. In the first homogenization, elastic constants of the transtropic material of each of the two regions are determined. In the repeated homogenization, the region of the first type is taken as a "conditional" fiber, the region of the second type is taken as a "conditional" matrix. Effective elastic constants for a composite reinforced with two types of isotropic hollow fibers are calculated. The proposed method gives a good convergence of the results with calculations by known formulas. The maximum relative calculation error for the longitudinal elastic characteristics compared to known formulas does not exceed 0,05 %. The dependences of some effective elastic constants on the volume content of hollow fibers of various types are constructed. Using this approach, three-component composites can be modeled varying the materials of the matrix, hollow fibers and their volume content. This allows predicting the strength of such composites under certain deformations at the design stage.

Because of the incorporation of discontinuous fibers, steel fiber-reinforced concrete (SFRC) outperforms regular concrete. However, due to its complexity and limited available data, the development of SFRC strength prediction techniques is still in its infancy when compared to that of standard concrete. In this paper, the compressive strength of steel fiber-reinforced concrete was predicted from different variables using the Random forest model. Case studies of 133 samples were used for this aim. To design and validate the models, we generated training and testing datasets. The proposed models were developed using ten important material parameters for steel fiber-reinforced concrete characterization. To minimize training and testing split bias, the approach used in this study was validated using the 10-fold Cross-Validation procedure. To determine the optimal hyper-parameters for the Random Forest algorithm, the Grid Search Cross-Validation approach was utilized. The root mean square error (RMSE), coefficient of determination (R2), and mean absolute error (MAE) between measured and estimated values were used to validate and compare the models. The prediction performance with RMSE = 5,66, R2 = 0,88 and MAE = 3,80 for the Random forest model. Compared with the traditional linear regression model, the outcomes showed that the Random forest model is able to produce enhanced predictive results of the compressive strength of steel fiber-reinforced concrete. The findings show that hyperparameter tuning with grid search and cross-validation is an efficient way to find the optimal parameters for the RF method. Also, RF produces good results and gives an alternate way for anticipating the compressive strength of SFRC.

Індекс рубрикатора НБУВ: О76-022

Рубрики:

Газопроводи

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ