# Кафедра системотехніки (СТ)

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Публікація 3D моделювання місцевості з вкиористанням дронів(ХНУРЕ, 2019) Прядка, Д. О.Показати більше The given work presents description of process of using 3D reconstruction technique based on 2D pictures of a building taken by a quadcopter . The latter is an unmanned aerial vehicle (UAV) being used to survey buildings of various heights without interfering with public transport. Moreover, the quadcopter can reach any position required to take the necessary angle for a favourable photos that should be connected together in 3D model. 3D technology is often used in different spheres of life because creating 3D model of real object allow to research and analyze information about real object easily with help of software.Показати більше Публікація A generalized algebraic approach to finding rough set approximations and generating logic rules(WIT Transactions on Information and Communication Technologies, 2007) Sitnikov, D.; Ryabov, O.; Titova, O.; Romanenko, O.Показати більше The rough set concept is a relatively new mathematical approach to vagueness and uncertainty in data. The rough set theory is a well-understood formal framework for building data mining models in the form of logic rules, on the basis of which it is possible to issue predictions that allow the classification of new cases. The indiscernibility relation and approximations based on this relation form the mathematical basis of the rough set theory. The classical topological definitions of rough approximations are based on this relation. Unlike the classical approaches it is possible to define rough approximations in an algebraic way. This paper represents a generalization of the algebraic approach suggested by the authors earlier. We use a set of discrete characteristic functions taking on values from finite sets (not necessarily Boolean values) and operations on them including comparison and Boolean operations, which we call the approximation language. We use the terms \“exact upper approximation” and \“exact lower approximation” to stress the fact that there can exist a variety of approximations but it is always possible to select the approximations that cannot be improved in the terms of the approximation language. We consider the process of generating logic rules based on the exact approximations in the case of arbitrary discrete characteristic functions taking on values from finite sets. Logic rules are naturally obtained from predicate formulae for the exact approximations. The introduced approach allows the generation of logic rules quickly and efficiently since only comparison operations with discrete values and Boolean operations with binary values are used to produce logic formulae.Показати більше Публікація A method for association rule quality evaluation based on information theory(WIT Transactions on Information and Communication Technologies, 2006) Sitnikov, D.; Titova, O.; Ryabov, O.Показати більше The concept of patterns representing functional, logical and other dependencies in data lies in the basis of the Data Mining technology. One of the wide spread forms for representing discovered knowledge patterns is association rules. A method for evaluating an association rule from the viewpoint of information theory has been suggested, which allows us to calculate a generalized characteristic of associations (based on mutual information) with the help of the well known association rule parameters: Support, Confidence and Improvement. Using such a characteristic of associations complements the traditional association parameters and allows setting a linear order on the set of associations, which is useful for evaluating and filtering obtained dependencies. Besides we have carried out analysis of the dependence of the association rule self-descriptiveness on the standard parameters.Показати більше Публікація A method for building desktop software automated update systems(WIT Transactions on information and communication technologies, 2013) Sitnikov, D.; Sitnikov, A.; Ryabov, O.Показати більше One of the problems in modern software development is the problem of introducing changes and fixes to the deployed software products in an automated fashion thus not requiring the end user to download the redundant product modules that had not been changed and performing manually the uninstall/install/check sequence. In this paper a method for building an automated update system has been suggested. The automated update system guarantees that the end user receives the latest changes and fixes to the product thus maintaining smooth experience from the software product. In this paper one of the methods for implementation of an automatic software update system for desktop applications is considered.Показати більше Публікація A method for finding minimal sets of features adequately describing discrete information objects(WIT Transactions on Information and Communication Technologies, 2009) Sitnikov, D.; Titova, O.; Romanenko, O.; Ryabov, O.Показати більше One of the classical Data Mining problems is the problem of classifying new objects on the basis of available information when the information associated with these objects does not allow identifying them unambiguously as elements of some set. In such cases using rough sets theory is often an effective solution. This theory operates with such concepts as \“indiscernible” elements and relations. A rough set is characterized by lower and upper approximations for finding which the authors earlier suggested an original algebraic method. The given method uses only logic operations, which makes the process of searching logic rules very quick and efficient. The upper and lower approximations of a rough set allow describing elements of this set as completely as it is possible from the viewpoint of available information. In this connection it seems interesting and important to find irreducible sets of features describing a rough set with the same \“precision” as with the help of a full set of features (so called reducts). This problem is quite difficult and complicated and at present it does not have good solutions. Our paper continues research carried out by the authors earlier and we suggest a method for finding reducts based on eliminating non-salient features in the reverse order of their importance. The suggested procedure allows us to avoid exhaustive searching by extracting a predefined number of most significant reducts. In this paper we consider arbitrary features taking on their values from finite sets. Keywords: rough set, low approximation, upper approximation, boundary region, reduct.Показати більше Публікація A method for knowledge representation and discovery based on composing and manipulating logical equations(Management Information Systems, 2002) Sitnikov, D. E.; D'Cruz, B.; Sitnikova, P. E.Показати більше The logical correlation in knowledge bases and development of a method for knowledge representation and discovery of dependencies between selected data features is discussed. It is pointed out that a knowledge base containing links between information features is represented in the form of logical equations. It is stated that extensible mark-up language (XML) is suitable for the writing of knowledge base in a text file. A subset of XML is developed which allows the data storage in a text file and help in discovering hidden patterns in the data by manipulating XML nodes.Показати більше Публікація A multicriteria model for solving a real cutting layout problem in publishing industry(ProjMAN, 2015) Grebennik, I. V.; Grytsay, D. V.; Mishcheriakov, I. V.; Basto-Fernandes, V.; Yevseyeva, I. V.Показати більше A cutting layout problem is analyzed taking into account the need to use standard-sized sheets of material for printing patterns with different size, type and print run. In this paper a multicriteria model is proposed for cutting layout problem and for printing an additional print run in particular. The multicriteria formulation of the cutting layout problem is considered, where the material waste, the number of the nesting patterns and the cutting layout cost are minimized simultaneously. The paper provides an approach to solve the problem using the additive multicriteria estimation. The efficiency of the proposed multicriteria model is tested for a series of computational experiments. Аналізується завдання розкладки макета з урахуванням необхідності використання аркушів стандартного розміру для друку шаблонів із різними розмірами, типом і тиражом. У цій статті запропонована багатокритеріальна модель для вирішення проблеми розкладки макета і для друку, зокрема, додаткового тиражу. Розглянуте багатокритеріальне формулювання проблеми розкрою, де матеріальні відходи, кількість вкладених шаблонів і вартість розкладки макета одночасно зводяться до мінімуму. У статті представлений підхід до вирішення проблеми з використанням адитивної багатокритеріальної оцінки. Ефективність запропонованої багатокритеріальної моделі перевірена на низці обчислювальних експериментів.Показати більше Публікація An algebraic approach to defining rough set approximations and generating logic rules(WIT Transactions on Information and Communication Technologies, 2004) Sitnikov, D.; Ryabov, O.Показати більше The rough set concept is a relatively new mathematical approach to vagueness and uncertainty in data. The rough set theory is a well-understood formal framework for building data mining models in the form of logic rules, on the basis of which it is possible to issue predictions that allow classifying new cases. The indiscernibility relation and approximations based on this relation form the mathematical basis of the rough set theory. The classical topological definitions of rough approximations are based on the indiscernibility relation. Unlike the classical approaches, in this paper we define rough approximations in an algebraic way. We use a set of predicates and predicate operations, which we call the approximation language. We introduce the terms "exact upper approximation" and "exact lower approximation" to stress the fact that there can exist a variety of approximations but it is always possible to select the approximations that cannot be improved in the terms of the approximation language. These new definitions are compared to the classical ones (which use an equivalence relation) and are shown to be more general in the sense that the classical definitions can be deduced from them if we put some restrictions on our model. The process of generating logic rules based on the exact approximations has also been considered. Logic rules are naturally obtained from predicate formulae for the exact approximations. The introduced approach allows generating logic rules quickly and efficiently since only Boolean operations with binary strings are used to produce logic formulae.Показати більше Публікація An algorithm for building a project team considering interpersonal relations of employees(2016) Imanhulova, Z.; Kolesnyk, L.; Імангулова, З. А.; Колесник, Л. В.Показати більше The setting of the problem of building a project team considering interpersonal relations between the employees was formulated. To assess the optimality of the team, a criterion is proposed that characterizes the contribution of employees to group interaction. The algorithm of solution of the problem of building a project team by the criterion of the maximum total contribution of employees to group interaction was developed. Сформульовано постановку задачі формування команди проекту з урахуванням міжособистісних взаємин співробітників. Для оцінки оптимальності складу команди проекту запропоновано критерій, що характеризує внесок співробітників у групову взаємодію. Розроблено алгоритм розв'язання задачі відбору кандидатів у команду проекту за критерієм сумарного внеску співробітників у групову взаємодію.Показати більше Публікація An approach to finding reduced sets of information features describing discrete objects based on rough sets theory(WIT Transactions on Information and Communication Technologies, 2008) Sitnikov, D.; Titova, O.; Romanenko, O.; Ryabov, O.Показати більше Modern Data Mining methods allow discovering non-trivial dependencies in large information arrays. Since these methods are used for processing and analysis of huge information volumes, reducing the number of features necessary for describing a discrete object is one of the most important problems. One of the classical problems in intelligent data analysis is the problem of classifying new objects based on some a-priori information. This information might not allow us to exactly classify an object as one belonging to a certain set. In such cases using rough sets theory may be an effective solution as this theory operates with the concept of \“indiscernible” elements and ambiguous information. In this paper we introduce a concept of a local reduct as a reduced set of features allowing us to describe a particular subset of the original set with the same precision as with the help of the full set of features. A method has been suggested which allows finding reduced sets of features adequately describing a rough set without losing necessary information (so-called reducts), and also assessing the importance of each feature. The suggested method is based on the algebraic approach to finding rough set approximations developed by the authors earlier. The main idea of the developed approach is as follows: if the algebraic approximations of a rough set do not change substantially in the process of excluding features the resulting reduced set of features can be used instead of the original full set. Also the greater changes eliminating a particular feature causes in the approximations, the more important this feature is. Keywords: data mining, rough sets, rough approximations, reduct.Показати більше Публікація Analytical identification of the unmanned aerial vehicles' surfaces for the implementation at a 3D printer(PC «TECHNOLOGY CENTER», 2019) Petrova, R.; Sheyko, T.; Maksymenko-Sheyko, K.; Sirenko, V.; Morozova, A.Показати більше Based on the R-functions theory, new approaches to analytical identification of drone surfaces for realization of 3D printing technology have been developed. The R-functions theory allows one to describe geometric objects of a complex shape with a single analytical expression, that is, obtain a mathematical model of the object in a form of an equation. To derive such equations, we used both the well-known standard primitive (sphere, ellipsoid, cylinder, cone, pyramid, etc.) procedure and a new approach, blending on a frame, which enables derivation of multiparameter equations with specified properties. Multiparameter equations of surfaces of drones of various types and purposes have been derived and visualized. Adequacy of the results to the designed objects was confirmed by visualization, both in conditions of operation of the RFPreview program and by realization on a 3D printer. The use of literal parameters when specifying geometric information in an analytical form makes it possible to promptly change size and shape of the designed objects which helps reduce time required to build computational models. The proposed method can reduce labor input in operation of CAD systems by months in cases when it is necessary to view a large number of design variants in a search for an optimal solution. Having the object equation, one can easily obtain equation of any of its sections which is useful for numerical calculations, namely, when building computational meshes. This can have a great effect on reducing complexity in construction of computational models for determining aero-gas-dynamic and strength characteristics. Characterization is also often associated with the need to account for changes in the aircraft shape. This leads to the fact that establishment of aerodynamic characteristics just because of the need to build a large number of computational models to account for this factor increases work duration by months. When specifying parameters, change of the rated operating conditions is made almost instantly.Показати більше Публікація Combined method of ranking options in project decision support systems(ХНУРЕ, 2020) Beskorovainyi, V.Показати більше The subject of research in the article is the process of ranking options in project decision support systems. The goal of the work is to create a method for ranking options to improve the efficiency of decision support systems by coordinating the interaction between automatic and interactive procedures of computer-aided design systems. The following tasks are solved in the article: review and analysis of the current state of the problem of ranking options in design decision support systems; decomposition of the problem of project decision support; development of a combined method of ranking options, which combines the procedures of technologies of ordinalistic and cardinalistic ordering; development of a method of minimax selection of options from a set of effective for the procedure of expert evaluation. The following methods are used: systems theory, utility theory, optimization and operations research. Results. As a result of the analysis of the modern methodology of decision support, the existence of the problem of correct reduction of subsets of effective design options for ranking, taking into account factors that are difficult to formalize, knowledge and experience of the decision maker (DM), has been established. The decomposition of the problem of supporting the making of design decisions into the tasks of determining the goal of designing an object, forming a universal set of design decisions, identifying sets of admissible and effective decisions, ranking and choosing the best design option for decision makers has been performed. A combined method for ranking options has been developed, which combines the procedures of ordinalistic and cardinalistic ordering technologies and allows you to correctly reduce subsets of effective design solutions for ranking decision makers. A method of minimax selection of options from a set of effective ones for the expert evaluation procedure of decision makers has been developed, which allows improving the quality of the assessment. Conclusions. The developed method expands the methodological foundations of automation of processes for supporting multi-criteria design decisions, allows for the correct reduction of the set of effective alternatives for the final choice, taking into account factors that are difficult to formalize, knowledge and experience of decision makers. The practical use of the results obtained due to the proposed procedure for determining the set of effective solutions will reduce the time and capacitive complexity of decision support, and due to the use of the maximin procedure for selecting options in the synthesis of the estimation model – to improve the quality of design solutions.Показати більше Публікація Construction of optimal wire sensor network for the area of complex share(Украинская государственная академия железнодорожного транспорта, 2016) Pankratov, A.; Antoshkin, A.Показати більше The problem of constructing a wired sensor network for a domain of complex shape is considered. To model the conditions of the problem, phi-functions and new functions of belonging to the domain point are used. A mathematical model of the joint covering and tracing problem is constructed in the form of a problem of nonlinear optimization. Effective search algorithms for locally optimal solutions are proposed. The results of computational experiments and a comparison of the results obtained are presented. Рассматривается задача построения проводной сенсорной сети для области сложной формы. Для моделирования условий задачи используются phi-функции и новые функции принадлежности точки области. Строится математическая модель совместной задачи покрытия и трассировки в виде задачи нелинейной оптимизации. Предлагаются эффективные алгоритмы поиска локально-оптимальных решений. Приводятся результаты вычислительных экспериментов и сравнение полученных результатов.Показати більше Публікація Defining logic structures in functional spaces(WIT Transactions on Information and Communication Technologies, 2007) Sitnikov, D.; Matski, N.; Ryabov, O.Показати більше Many practical problems of geometric information representation and pattern recognition require specific methods and tools for describing complex functions and geometric objects in a way that allows us to use such descriptions for making effective mathematical transformations and logic inferences. Since in real world situations we rarely encounter ideal objects that can be described with the help of one elementary function it is important to develop methods and models for integrating geometric information. There are some original approaches to describing complicated geometric structures, one of which is a method based on so-called R-functions. These functions allow complicated geometric objects to be described analytically, which gives an opportunity to operate with complex objects with the help of a single real function. The concept of R-functions is quite simple but the range of practical applications of this theory is very broad. In this paper we have suggested a generalization of R-functions, which we call Rp-functions. Any R-function can be associated with a Boolean function and it is always possible to construct an R-function corresponding to a given Boolean one. Similarly, any Rp-function can be associated with a finite predicate and it is always possible to construct an Rp-function corresponding to a given predicate. If R-functions allow us to use Boolean logic for describing complex objects, Rp-functions provide a possibility of using predicate logic, which is more rich and general than Boolean one. Like R-functions, Rp-functions allow the use of knowledge on what logic rules have been used for constructing a complex object to build a function which is positive inside the given domain and negative outside it. Rp-functions also seem to be interesting by themselves as they allow discovery of logic properties of quite a large class of real functions.Показати більше Публікація Determining preferences in recommender systems based on comparator identification technology(ХНУРЕ, 2022) Beskorovainyi, V.; Kolesnyk, L.; Alokhina, M.; Кosenko, V.Показати більше The subject of research in the article is the process of ranking objects in the lists of recommender systems. The goal of the work is to increase the efficiency of recommender systems by improving the method of determining preferences between objects in lists using the theory of multi-criteria decision-making. The following tasks are solved in the article: review and analysis of the current state of the problem of identifying advantages between objects and their ranking in the lists of recommender systems; analysis of filtering methods used in recommendation systems; decomposition of the decision support problem for selection of objects; development of a combined method for ranking objects in the lists of recommender systems, combining the procedures for selecting a subset of Pareto-optimal objects, structural-parametric synthesis of a scalar multi-criteria estimation model, and evaluating the entire set of selected objects. The following methods are used: mathematical modeling, systems theory, utility theory, decision theory, optimization and operations research. Results. Based on the results of the analysis of the modern methodology for ranking objects in the lists of recommendation systems, the possibility of increasing their efficiency has been established. To take into account factors difficult to formalize, the knowledge and experience of users, it is proposed to implement the determination of preferences between objects using the theory of multi-criteria decision making. The problem of forming lists of recommendation systems is decomposed into the tasks of selecting a subset of Pareto-optimal objects, structural-parametric synthesis of a scalar multi-criteria estimation model, and evaluating a set of selected objects. A combined method for ranking options has been developed that combines the procedures of ordinalistic and cardinalistic ordering technologies and allows one to correctly reduce the subsets of objects included in the lists of recommendations. Conclusions. The developed method for determining preferences expands the methodological foundations for automating the development and operation of recommendation systems, other multi-criteria decision support systems, allows for the correct reduction of the set of non-dominated objects for the final choice, taking into account factors that are difficult to formalize, knowledge and user experience. The practical use of the obtained results due to more economical method of forming lists when adding new objects will allow to decrease the time and capacity complexity of the procedures for providing recommendations, and due to taking into account of set of weighted local indexes and allocation of set of non-dominated objects - to increase quality of given recommendations.Показати більше Публікація Developing software for solving some combinatorial generation and optimization problems(UNWE, 2017) Grebennik, I. V.; Lytvynenko, O. S.Показати більше Software for solving various problems of combinatorial generation and combinatorial optimization is described. Firstly, programmatic implementation of algorithm for generating classical combinatorial sets (combinations, permutations, arrangements) and algorithm for generation of k-compositions of combinatorial sets were described. Then, implementation of algorithm for generation of permutations with partially fixed order of elements was described. Also article describes applications for solving three different combinatorial optimization problems – pickup and delivery problems with 3D loading constraints, problem of scheduling freight trains in rail-rail transshipment yards with train arrangement and problem of optimization of linear function on a set of cyclic permutations. Описано программное обеспечение для решения различных задач комбинаторной генерации и комбинаторной оптимизации. В первую очередь, была описана программная реализация алгоритма генерации классических комбинаторных множеств (комбинаций, перестановок, аранжировок) и алгоритма генерации k-композиций комбинаторных множеств. Затем была описана реализация алгоритма генерации перестановок с частично фиксированным порядком элементов. Также в статье описываются приложения для решения трех различных задач комбинаторной оптимизации – проблемы с доставкой и доставкой с трехмерными нагрузками, проблема расписания грузовых поездов в железнодорожных перевалочных пунктах с поездами и проблема оптимизации линейной функции на множестве циклических перестановок.Показати більше Публікація Development and research methods of formation and functioning of intellectual team(2018) Ponomarova, S. V.Показати більше The work is devoted to the task of intellectual team’s management, namely the problem of their formation, adaptation and training. The paper presents a mathematical model of the multifactor estimation of intellectual team, allowing to choose the best of its composition from a plurality of possible options. To formalize the problem using utility theory, candidates in the team are assessed for their professional, profile and personality characteristics.Показати більше Публікація Development of the social network «myHobby»(ХНУРЕ, 2023) Мітрошкіна, К. В.Показати більше This work is devoted to developing the social network myHobby, the main goal of which is to bring people together according to their interests, help find and be aware of various events and popular communities around the world, and be able to find new hobbies and grow professionally. myHobby is focused on sharing hobby-related content such as articles, photos, and videos as well as a marketplace for buying and selling related goods and forums for discussion. Social networks are very popular in today's world, so the main idea is to use one to attract people to physical activity, creativity, and discovering new talentsПоказати більше Публікація Directed search of variants in technologies for reengineering of corporate computer networks(2021) Beskorovainyi, V.; Russkin, V.Показати більше The formalization of the multicriteria task of system reengineering of a corporate computer network is proposed. It presupposes structural, topological, parametric and technological optimization of the network in terms of a complex “effect-cost” indicator. The parameters of the quality of the variants are detailed in the form of particular criteria of costs, efficiency, reliability and survivability. This allows us to reduce the multicriteria task to a traditional optimization task with a scalar criterion. The proposed approach to the formation of a subset of effective ones already at the stage of generation of feasible variants can significantly reduce the time and capacitive complexity of methods for solving the task of network reengineering. For the final choice of the reengineering variant by the decision maker, it is proposed to reduce to the required size the subsets of effective alternatives using the known combined methodПоказати більше Публікація Discovering salient data features by composing and manipulating logical equations(Management Information Systems, 2000) Sitnikov, D. E.; D'Cruz, B.; Sitnikova, P. E.Показати більше The paper suggests a method of representing knowledge in the form of logical equations of a special type. We show that deductive inferences about the salient data features in a knowledge base can be represented by a set of logical equations. We describe how logical equations with finite predicates can be successfully used for the description of logical links between discrete features, and how this can be applied to pattern recognition and data mining. New knowledge about logical links between discrete features in the data can be obtained by eliminating variables from these equations with the help of the operation ∃, and we describe this process in detail. We consider the application of the operation ∃ to a logical equation as an analogue to a query in a database. The process results in a dependence between the features subsequent to application of the elimination procedure that is easier to interpret than the dependence represented in the original equations, and is obtained without the need for exhaustive searching. We recursively define a class of finite predicates that allow eliminating variables without increasing the size of the original equation, and show how this can be applied for knowledge discovery using logical data modelling.Показати більше