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Статті в журналах з теми "621.431:004.896"
Yu, Xiao Dong, Zhi Qiang Wang, Xiu Li Meng, Qi Hui Zhou, Yan Qin Zhang, Lan Yang, and Hui Jiang. "Comparative Study on Pressure Field of Hydrostatic Thrust Bearing with Different Recess Shapes." Key Engineering Materials 621 (August 2014): 431–36. http://dx.doi.org/10.4028/www.scientific.net/kem.621.431.
Повний текст джерелаДисертації з теми "621.431:004.896"
Савосько, Олександра Миколаївна. "Нейромережеві засоби виявлення шкідливого трафіку з ієрархічним механізмом уваги". Master's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/45918.
Повний текст джерелаActuality of theme. Today, the importance of intrusion detection systems in computer networks is one of the main issues that must be addressed. Wireless networks are developing and proliferating rapidly these days, giving a large number of users the ability to be mobile 24/7. At the same time, the question arises that every user wants to be protected from attacks on personal information. Modern computer attack detection systems do not provide an adequate level of protection of computer systems, their methods have a number of drawbacks. So, the most precise method nowadays, based on signature analysis, works well for detecting already known computer attacks but is completely useless for detecting new ones, previously unknown. And, as practice shows, new, previously unknown, computer attacks are the cause of global information disasters and lead to huge financial and moral damage. Various heuristic methods have been developed to protect computer systems from unknown attacks. But they are characterized by a high level of errors of the first and second kind (the probability of missing an attack and the probability of erroneous responses), which makes them difficult to use. An additional disadvantage of existing systems is high computational complexity. This situation stimulates the development of new approaches for the detection of computer attacks. The object of research is the problem of detecting malicious traffic in the network. The subject of research is ways to detect intrusions on the basis of a variety of approaches and principles. The goal of the work: the creation of a model of detection of abuse in the network based on the neural recurrent network, combined with a hierarchical mechanism of attention. The scientific novelty is a proposed model based on an efficient, robust deep recurrent neural network, divided into five parts. Specifically, the input layer, the feature transformation part, the bi-directional gating memory block part, the hierarchy part, and the output part of the multilevel perseptron. An attention mechanism is introduced to focus on abnormal flows in the data flow segment when using limited computational resources. By combining information about the three levels of operations, namely the attention mechanism hierarchy, the maximum association hierarchy, and the average association hierarchy, the model's ability to detect interference is improved. So that the model can improve the throughput per unit time and ensure the effectiveness of network interference detection, this paper proposes a data processing method that divides the flow data into segments. Practical value of the results obtained in this work is that the proposed model not only improves the detection performance of malicious traffic, but also provides a new research method to improve the detection performance of the model. Approbation of work. The main theses and results of work were presented and discussed on XIV scientific conference of undergraduate and graduate students "Applied mathematics and computer" PMK-2021 (Kiev, November 17-19, 2021). Also articles were published at conferences of XIII All-Ukrainian scientific-practical conference "Actual problems of computer sciences APKN-2021" (Kyiv, November 26, 2021) and IX International scientific-practical Internet-conference of young scientists and students "Actual problems of automation and management" (Kyiv, November 30, 2021). Structure and scope of work. The master's dissertation consists of an introduction, five chapters and conclusions. In the introduction, a general description of the work is presented, an assessment of the current state of the problem is made, the relevance of the research direction is substantiated, goals and objectives of research are formulated, the scientific novelty of the results and the practical value of the work are shown, information about approbation of results and their implementation is given. The first chapter reviews the problems of malicious traffic detection and the existing methods of its detection. The second section presents an analysis of the dataset that was used to train the neural network. The third chapter describes the process of obfuscation of the training data. The fourth section describes the selected method for detecting malicious traffic and its features. In the fifth section, the analytical analysis of the developed method and the results obtained. The conclusions summarize all the work done to create the presented network and the results of the work performed.
Мордвінцева, Ірина Олександрівна. "Моделювання в САПР нестаціонарних термічних навантажень та ресурсної міцності поршнів швидкохідних дизелів". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40132.
Повний текст джерелаThesis for the science degree of the Candidate of technical sciences by specialіty 05.05.03 – engines and power plants. – National Technical University "Kharkov polytechnic institute", Kharkov, 2018. The thesis is devoted to modeling in CAD of non-stationary thermal stresses and resource durability of pistons of high-speed diesel engines. The dissertation is devoted to the modeling of non-stationary thermal loads and resource strength of high-speed diesels in CAD. It has been found that for modeling the thermal state of the piston in the transient processes diesel, it is necessary to use non-stationary models of operation. In this case, when the boundary conditions are imposed, it is necessary to have data on control functions that including the time of the transition process. The allowable simplifications of the border conditions problem in the characteristic zones of the piston in the calculations of the thermal and thermo-stressed state of the piston on the stationary and in the transient processes of the diesel load are determined. Their use allows to shorten the design time without violating the concept of guaranteed maintenance of the resource of the edge of the combustion chamber in the initial stages of CAD application. An experimental study was conducted to determine the thermal of a piston for a 4CHN12/14 diesel engine in transient diesel processes. According to the study, control functions are defined for each transient process. A complex of mathematical models for the determination of the thermal and thermo-stressed state of the piston in the transient processes of the diesel is proposed. With simplified border conditions, the reliability of the results proposed to set the indicator of the relative estimated increase in the resource. According to the results of the research, the effect of the shift in time of the step change of the BC of the 3rd kind of a piston in the transient process of the diesel engine on the resource strength of the edge of the combustion chamber is established. This measure allows to increase the efficiency of CAD on stationary and non-stationary loads and when performing the evaluation of the resource strength of the pistons. New designs of pistons with oil-cooling cavities are proposed.
Мордвінцева, Ірина Олександрівна. "Моделювання в САПР нестаціонарних термічних навантажень та ресурсної міцності поршнів швидкохідних дизелів". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40129.
Повний текст джерелаThesis for the science degree of the Candidate of technical sciences by specialіty 05.05.03 – engines and power plants. – National Technical University "Kharkov polytechnic institute", Kharkov, 2018. The thesis is devoted to modeling in CAD of non-stationary thermal stresses and resource durability of pistons of high-speed diesel engines. The dissertation is devoted to the modeling of non-stationary thermal loads and resource strength of high-speed diesels in CAD. It has been found that for modeling the thermal state of the piston in the transient processes diesel, it is necessary to use non-stationary models of operation. In this case, when the boundary conditions are imposed, it is necessary to have data on control functions that including the time of the transition process. The allowable simplifications of the border conditions problem in the characteristic zones of the piston in the calculations of the thermal and thermo-stressed state of the piston on the stationary and in the transient processes of the diesel load are determined. Their use allows to shorten the design time without violating the concept of guaranteed maintenance of the resource of the edge of the combustion chamber in the initial stages of CAD application. An experimental study was conducted to determine the thermal of a piston for a 4CHN12/14 diesel engine in transient diesel processes. According to the study, control functions are defined for each transient process. A complex of mathematical models for the determination of the thermal and thermo-stressed state of the piston in the transient processes of the diesel is proposed. With simplified border conditions, the reliability of the results proposed to set the indicator of the relative estimated increase in the resource. According to the results of the research, the effect of the shift in time of the step change of the BC of the 3rd kind of a piston in the transient process of the diesel engine on the resource strength of the edge of the combustion chamber is established. This measure allows to increase the efficiency of CAD on stationary and non-stationary loads and when performing the evaluation of the resource strength of the pistons. New designs of pistons with oil-cooling cavities are proposed.
Дмитренко, Тарас Васильович. "Експертна система для оцінки якості стиснення зображень та аудіоінформації". Thesis, Національний авіаційний університет, 2021. https://er.nau.edu.ua/handle/NAU/50354.
Повний текст джерелаДля оцінки результатів проведених дій над масивами даних, які представлені у вигляді зображень і аудіо сигналів в реальному масштабі часу було запропоновано використати експертну систему. Враховуючи, що існують новітні технології та підходи, які можуть допомогти автоматизувати певні етапи або процеси використовуючи знання експертів в певній області знань відповідно до вимог та завдань користувача. Запропоновано систему, яка дає можливість отримати оцінку результату дій над масивами даних.
It was proposed to use an expert system to evaluate the results of the actions performed on data sets, which are presented in the form of images and audio signals in real time. Given that there are the latest technologies and approaches that can help automate certain stages or processes using the knowledge of experts in a particular field of knowledge in accordance with the requirements and tasks of the user. A system is proposed that allows to obtain an estimate of the result of actions on data sets.
Ференс, Дмитро Андрійович. "Дослідження методів розподілу ресурсів критичної ІТ інфраструктури за допомогою технологій штучного інтелекту". Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/23028.
Повний текст джерелаThe analysis of existing problems in IT infrastructure resources management is carried out. Methods of application of artificial intelligence technologies for solving the problem of resource allocation are proposed. A modified fitness function is proposed, which performs optimal infrastructure resource destribution, taking into account their current locations. A comparison of the developed algorithms with existing ones was performed, which proved high quality of the obtained results.
Проведен анализ существующих проблем в управлении ресурсами ИТ инфраструктуры. Предложенные способы применения технологий искусственного интеллекта для решения задачи распределения ресурсов. Предложен модифицированный вариант фитнес-функции, который позволяет осуществлять оптимальное распределение элементов инфраструктуры, учитывая их текущее положение. Проведено сравнение разработанных алгоритмов с существующими и подтверждено высокое качество полученных результатов.
Плюгін, Владислав Євгенович. "Теоретичні основи об'єктно-орієнтованого проектування електромеханічних перетворювачів енергії". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/19109.
Повний текст джерелаThe dissertation on competition of a scientific degree of the doctor of technical sciences on specialty 05.09.01 – electrical machines and apparatus. National technical university "Kharkiv polytechnic institute", Kharkiv, 2015. Dissertation is devoted to development of the new way of design and modelling of electromechanical converter of energy (EMCE), which is based on the basic concepts of the object-oriented analysis. The object-oriented classification of specific variety of EMCE that has a compatible single template for all EMCE and combines the functions of EMCE organization with a parallel mathematical reflection is worked out by a competitor. A competitor is work out EMCE classifications models, included not only structure development but also parallel synthesis of mathematical models and design programs. For the first time is suggested to use a single class template for structural and system organization of EMCE, invariant to their specific variety. Applicability of the object-oriented way in the EMCE optimal design with the use of modern optimization algorithms and technical documentation automatic generation is grounded. A competitor executes a project synthesis and programmatic realization of the object-oriented design of double-stator screw EMCE with an external solid rotor, brushless turbogenerator exciter and induction motor with squirrel cage rotor. Obtained results have high correlation with data, got experimentally.
Плюгин, Владислав Евгеньевич. "Теоретические основы объектно-ориентированного проектирования электромеханических преобразователей энергии". Thesis, НТУ "ХПИ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/19111.
Повний текст джерелаThe dissertation on competition of a scientific degree of the doctor of technical sciences on specialty 05.09.01 – electrical machines and apparatus. National technical university "Kharkiv polytechnic institute", Kharkiv, 2015. Dissertation is devoted to development of the new way of design and modelling of electromechanical converter of energy (EMCE), which is based on the basic concepts of the object-oriented analysis. The object-oriented classification of specific variety of EMCE that has a compatible single template for all EMCE and combines the functions of EMCE organization with a parallel mathematical reflection is worked out by a competitor. A competitor is work out EMCE classifications models, included not only structure development but also parallel synthesis of mathematical models and design programs. For the first time is suggested to use a single class template for structural and system organization of EMCE, invariant to their specific variety. Applicability of the object-oriented way in the EMCE optimal design with the use of modern optimization algorithms and technical documentation automatic generation is grounded. A competitor executes a project synthesis and programmatic realization of the object-oriented design of double-stator screw EMCE with an external solid rotor, brushless turbogenerator exciter and induction motor with squirrel cage rotor. Obtained results have high correlation with data, got experimentally.
Шимкович, Володимир Миколайович. "Методи та засоби проектування апаратних компонентів нейромережевих систем керування". Thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/40489.
Повний текст джерелаThe dissertation is devoted to solving the problem of increasing the efficiency of the components of neural network control systems, which allow to synthesize neural network control systems that function and adapt in real time taking into account the specifics of control tasks. ANN can be used in facilities such as robotics, unmanned aerial vehicle control, vehicle control, pattern recognition, analysis and decision making in the Internet of Things, spacecraft control, military equipment and many other applications of modern technologies. In these systems, neural networks can be used to identify objects, predict the state of objects, recognize, cluster, classify, analyze large amounts of data coming at high speed from a large number of devices and sensors, and more. ANN can be used to build control and correction devices, reference, adaptive, nominal and inverse-dynamic models of objects, based on which the study of objects, analysis of the impact of perturbations acting on the object, determining the optimal control law, search or calculation of the optimal program to change the control effect when changing the values of the parameters of the object and the characteristics of the input data. Dynamic expansion of embedded systems that require the use of hardware with ANN, to increase the efficiency of their work, determine the increased requirements for these hardware, their speed, accuracy and use of computing resources. Thus, the scientific and technical task of increasing the efficiency of hardware implementation of neural network components of control systems for dynamic objects, providing adaptation and self-tuning of control systems in real time is relevant. The purpose of the dissertation is to increase the efficiency of neural network control systems by creating high-speed components that allow you to implement the functions of identification, adaptation and control of dynamic objects in real time. The results of the research are presented in four sections of the dissertation. In dissertation analyzes the areas of application of ANN hardware, the main structures of neural network control systems for dynamic objects. Based on the analysis, it was found that neural network control systems consist of direct and inverse models of the control object and the component of their adaptation. Based on the ANN analysis, it has been established that several dozen types of ANN have been developed and researched to date, but the main, fundamentally different types are three types of networks: RBF-networks, Hopfield dynamic networks and direct distribution networks. Due to the properties ANN, they can be used for further design on their basis of direct and inverse models of the control object. The existing methods and algorithms of ANN learning are analyzed. Based on the analysis, it is established that the use of a genetic algorithm for training the neural network components of the CS is the most optimal for hardware implementation. The analysis of the current state of software, hardware and hardware-software means of realization of ANN is carried out. As a result of the analysis it was established that the means of implementation of neural network control systems should be focused on widespread use in industrial conditions, be universal and flexible, function and learn in real time, be simple and cheap, so the most promising tools can be considered FPGA. The review of the main works on realization of ANN by means of FPGA is carried out. In dissertation proposes a method for designing nonlinear activation functions of an artificial neuron on an FPGA. Based on the proposed method, algorithms for hardware implementation of an artificial neuron with sigmoidal activation function and a hidden layer neuron of the RBF network with a Gaussian activation function have been developed. A research of implemented artificial neurons and ANN was performed. It is shown that due to the developed method and algorithms significant optimization of the used resource is provided, the speed of calculations of hardware units with ANN and their accuracy in comparison with analogues increases. In manuscript develops technology for construction, research and evaluation of neural network models of multidimensional control objects for their further implementation. A method of designing hardware components, such as direct and inverse model of control object, neural network control systems, which are basic for structural synthesis of control systems, for calculation of state vectors of object and formation of control function is developed. The method of optimization of ANN weighting factors by means of genetic algorithm at realization on FPGA is developed that allows increasing considerably speed of adaptation of direct and inverse model of control object. In dissertation implemented and researched on the basis of the developed components: control systems without feedback; feedback control systems; adaptive control system with direct and inverse models of the control object; adaptive neural network control system with a reference model; a model of the operating neurocontroller of the stabilization system of a moving object on a limited plane is developed.
В диссертационной работе получено новое решение научно-технической задачи повышения эффективности работы компонентов нейросетевых систем управления, которые позволяют синтезировать нейросетевые системы управления, функционирующих и адаптируются в режиме реального времени с учетом специфики задач управления. Разработан метод проектирования сигмоидальной функции активации искусственного нейрона на основе FPGA и алгоритмы реализации искусственных нейронов. Разработаны методы проектирования аппаратных компонентов нейросетевых систем управления, таких как нейросетевая модель объекта управления и компонент ее адаптации, которые являются базовыми для структурного синтеза систем управления. Реализовано и исследовано, на основе разработанных компонентов, нейросетевые системы управления и разработан макет действующего нейроконтроллера системы стабилизации подвижного объекта на ограниченной плоскости. Исследования показали высокую эффективность и быстродействие разработанных компонентов.
Аріан, Расул. "Підвищення ефективності моделювання теплонапруженого стану поршнів ДВЗ у багатоетапній САПР". Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/31041.
Повний текст джерелаThesis for the degree of candidate of technical sciences by specialty 05.05.03 - engines and power plants. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2017. The thesis is devoted to the prediction of the heat stressed state and loss of strength of the pistons of internal combustion engines in CAD/CAE. Actuality of work is to increase the efficiency of the design process on the basis of compliance with the concept of guaranteed provision of the resource design. The analysis of the current state of methods, models and methods for predicting the heat stress state and edge resource of the combustion chambers of the forced engine pistons, the routes of the projects passing through the CAD/CAE is carried out in the work. It is shown that the existing deviations from the concept of guaranteed reliability in the applied techniques and models are associated with the possible unreasonable level of assumptions and simplifications of input, external, internal and output parameters of models and, accordingly, with unreasonable design routes. It is suggested to increase the efficiency of the design process on the basis of a comprehensive analysis of the permissible simplification of the geometric and design models, the engine operation model and the corresponding boundary conditions of the piston heat conduction problem. The technique of forecasting the accumulation of damages in the material of the piston is specified. The model of prediction of boundary conditions of the third kind is improved. A dependence of the heat transfer coefficient local on the surface of the combustion chamber is proposed, which takes into account the fuel advance angle. It is established that an increase in the fuel feed angle by 6 ° can more than double the relative damage of the piston material in the combustion chamber edge zone. The recommendations on the choice of the determining mode of loading of the engine are developed. The analysis of the features of the change in the temperature and thermonuclear state in the circumferential direction of the edge of the combustion chamber taking into account changes in the geometry of the piston, the engine boost level and other weighty factors is analyzed. It is shown for the first time that local changes in the geometry of the piston's fire surface can lead to multidirectional changes in the temperature and thermo-stressed state of such zones. The notion of the effect of the levels of simplification of geometry, the calculation model, the boundary conditions of the thermal conductivity of the piston on the results of calculating the strength of the edge of the combustion chamber of the piston is expanded. It has been established that simplifying the geometry of the piston in the zone of the edge of the combustion chamber can lead to a significant over-reduction, more than 35%, of the criterion of relative damage to the material. Such a simplification of the model leads to a violation of the concept of guaranteed assurance of the resource. The technique of passing the piston design in multi-stage CAD/CAE is improved. The example of diesel 4CHN12/14 analyzed the measures to ensure the resource strength of pistons and determined the numerical values of their impact. Two new designs of the piston with cavities of gallery oil cooling are offered.
Аріан, Расул. "Підвищення ефективності моделювання теплонапруженого стану поршнів ДВЗ у багатоетапній САПР". Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/31034.
Повний текст джерелаThesis for the degree of candidate of technical sciences by specialty 05.05.03 - engines and power plants. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2017. The thesis is devoted to the prediction of the heat stressed state and loss of strength of the pistons of internal combustion engines in CAD/CAE. Actuality of work is to increase the efficiency of the design process on the basis of compliance with the concept of guaranteed provision of the resource design. The analysis of the current state of methods, models and methods for predicting the heat stress state and edge resource of the combustion chambers of the forced engine pistons, the routes of the projects passing through the CAD/CAE is carried out in the work. It is shown that the existing deviations from the concept of guaranteed reliability in the applied techniques and models are associated with the possible unreasonable level of assumptions and simplifications of input, external, internal and output parameters of models and, accordingly, with unreasonable design routes. It is suggested to increase the efficiency of the design process on the basis of a comprehensive analysis of the permissible simplification of the geometric and design models, the engine operation model and the corresponding boundary conditions of the piston heat conduction problem. The technique of forecasting the accumulation of damages in the material of the piston is specified. The model of prediction of boundary conditions of the third kind is improved. A dependence of the heat transfer coefficient local on the surface of the combustion chamber is proposed, which takes into account the fuel advance angle. It is established that an increase in the fuel feed angle by 6 ° can more than double the relative damage of the piston material in the combustion chamber edge zone. The recommendations on the choice of the determining mode of loading of the engine are developed. The analysis of the features of the change in the temperature and thermonuclear state in the circumferential direction of the edge of the combustion chamber taking into account changes in the geometry of the piston, the engine boost level and other weighty factors is analyzed. It is shown for the first time that local changes in the geometry of the piston's fire surface can lead to multidirectional changes in the temperature and thermo-stressed state of such zones. The notion of the effect of the levels of simplification of geometry, the calculation model, the boundary conditions of the thermal conductivity of the piston on the results of calculating the strength of the edge of the combustion chamber of the piston is expanded. It has been established that simplifying the geometry of the piston in the zone of the edge of the combustion chamber can lead to a significant over-reduction, more than 35%, of the criterion of relative damage to the material. Such a simplification of the model leads to a violation of the concept of guaranteed assurance of the resource. The technique of passing the piston design in multi-stage CAD/CAE is improved. The example of diesel 4CHN12/14 analyzed the measures to ensure the resource strength of pistons and determined the numerical values of their impact. Two new designs of the piston with cavities of gallery oil cooling are offered.