Formation Of Initial Data Research Articles

Selection of aerodynamic characteristics and engine parameters of a maneuverable aircraft under epistemic uncertainty

At the preliminary stage of aircraft design, it is usually required to solve the problem of insufficient initial data for applying traditional algoristic-type mathematical programming models. In many cases, numerous input parameters cannot be accurately specified at the time of making design decisions. If the inaccuracy of parameters is not taken into account, the actual values of target functions may differ significantly from the calculated ones when solving optimization problems. In this regard, the issue of current interest is the development of algorithms to improve the reliability of design decisions under conditions of epistemological uncertainty when experts engage in the formation of initial data. The paper considers the problem of selecting aerodynamic characteristics and engine parameters of maneuverable aircraft under conditions of uncertainty associated with inaccuracy of expert data. The applied problem under consideration is further complicated by the necessity to include “black box” models in the algorithms being developed. The paper proposes algorithms that apply the uncertainty theory together with “black box” models that implement optimization calculation techniques derived from previous engineering practice of aircraft design. Using these algorithms, experts are able to set uncertain parameters whereby the lack of data is factored in using uncertainty distribution functions. In cases of monotonicity of uncertain parameters in target functions, application of the uncertainty theory provides a significant reduction in computational costs compared to the method of statistical modeling in optimization calculations. The paper presents the results of computational studies of the developed algorithms. A genetic algorithm (mathematical optimization solver) is used to optimize the search for design solutions. Pareto frontiers are obtained for different confidence levels enabling to make design decisions including values of aerodynamic characteristics and engine parameters of maneuverable aircraft.

Модель оценки функциональной устойчивости элементов информационной инфраструктуры для условий воздействия множества компьютерных атак

Information is given about a new approach to the application of methods of the theory of semi-Markov processes to solve the applied problem of assessing the functional stability of elements that make up the information infrastructure, functioning under the influence of multiple computer attacks. The task of assessing functional stability is reduced to the task of finding the survivability function of the element under study and determining its extreme values. The relevance of the study is substantiated. The rationale is based on the assumption that quantitative methods of studying the stability of technical systems, which operate on the theory of reliability, cannot always be used to assess survivability. The concepts of «stability» and «computer attack» are being clarified. Verbal and formal statements of research tasks are formulated. The novelty of the results obtained lies in the application of well-known methods to solve a practically significant problem in a new formulation, taking into account the limitations on the resource allocated to maintain the survivability of the element under study, provided that arbitrary distribution laws are adopted for the random times of the implementation of computer attacks and the recovery times of the functional element. Recommendations on the formation of initial data, the content of the enlarged stages of modeling and a test case to demonstrate the performance of the model are given. The results of the test simulation are presented in the form of graphs of the survivability function. The resulting application can be used in practice to construct a survivability function when implementing up to three computer attacks, as well as a tool for evaluating the reliability of analogous statistical models. The limitation is explained by a progressive increase in the dimension of the analytical model and a decrease in the possibility of its meaningful interpretation.

Method of digital automatic design of grinding operations carried out on CNC cylindrical grinding machines

Based on the literature review, the problem is formulated, which consists in the absence of detailed recommendations for the design of grinding operations for CNC cylindrical grinding machines. This paper provides a solution to the problem described above using the developed method, which includes: the formation of initial data, the formation of grinding cycles, and the calculated determination of cycle parameters.

EXPERIENCE OF OBTAINING INITIAL DATA FROM GOOGLE EARTH TO BUILD A DIGITAL TERRAIN MODEL

The Google Earth information system is the virtual globe built on connected photographs with terrain information and partially vectorized situation. The system has the ability to obtain information on the WGS-84 coordinates and the universal transverse Mercator projection of any point, but it requires research on the methodology for obtaining such information and the accuracy of spatial information. The answers to these questions will make it possible to specify the range of geodetic and design tasks that can be solved with Google Earth. It has been analyzed the latest research and publications in article. According to this analysis, the problem of using the Google Earth system for geodetic purposes remains relevant. The work focused on the formation of initial data from the Google Earth system in a convenient text format for further loading into a computer-aided design system to create a digital terrain model. An algorithm for obtaining initial data in the form of four columns has been compiled: the name of the point and three coordinates. In this format, you can perform any coordinate transformations with subsequent loading into other programs. The algorithm for obtaining initial data from Google Earth in text format will be as follows: 1) drawing up a plot survey scheme (determining the survey boundary, alphanumeric designation of streets for simplicity, highlighting survey objects, etc.); 2) creation of closed polygons (general survey area, all areal objects), polylines (all linear objects), marks (all point objects); 3) obtaining geodetic coordinates of nodes of areal objects and polylines; 4) creation of longitudinal profiles for finding heights. The problem of assessing the errors of the Google Earth system in the horizontal plane remains relevant in order to be able to form a digital model of the situation.

Расширение информационного обеспечения оценки производственной технологичности изделий

A methodological approach to the formation of initial data to implement the design procedure for assessing quantitative indicators of parts manufacturability is considered. This approach expands the set of analyzed design characteristics and provides opportunities for formalizing the implementation of technological preparation of machining industries.

Economic-mathematical model for complex risk assessment of the enterprise investment project using fuzzy logic

The article proposes an economic-mathematical model for determining a comprehensive risk assessment of the investment project of the enterprise which are based on the approaches of A. Nedosekin. The model is built using fuzzy logic and takes into account the probability of occurrence of each of the identified risks and the level of impact of each of them on the project. The probability of risk is set by experts in the form of points and converted into linguistic terms, and the level of influence of each of them on the project – the ratio of benefits and is determined using Fishburne scales. The proposed Project Risk Model consists of the following stages: formation of initial data using expert opinions; construction of a hierarchical project risk tree; determination of weight coefficients (Fishburne weights) of project risks; selection and description of membership function and linguistic variables; conversion of input data provided by experts from a score scale into linguistic terms; recognition of qualitative input data on a linguistic scale; determination of a complex indicator of investment project risks; interpretation of a complex indicator. The developed model allows managing the risks of the project to maximize the probability of its successful implementation, to compare alternative projects and choose less risky, to minimize the level of unforeseen costs of the project.

Системний підхід до оцінювання працездатності трактора на етапах його життєвого циклу

Purpose of the study. Substantiation of the methodology of a systematic approach to assessing the performance of a tractor at the stages of its life cycle. To achieve this goal, it is necessary to solve the following tasks: - explore the possibility of applying a systematic approach to assessing the performance of tractors; - to investigate the mechanism of applying a systematic approach to assessing the performance of tractors at the stages of their life cycle. Research methods. CALS-technology, which ensures the implementation of the strategy of organizing the production of new products based on new engineering technology, and is based on the electronic model of the product. The results of the study. The systematization of the functional indicators of the tractor, which form the basis of a systematic approach to assessing its performance at the stages of the life cycle, is carried out. The necessity of assessing the traction and energy indicators of the tractor by its dynamic and traction characteristics has been proved. The life cycle of a tractor is a set of interconnected processes of its creation and sequential change in state from the formation of initial data to the end of operation. At the same time, an effective system analysis of the life cycle of a tractor by a target criterion, for example, by its operability, which is characterized by the ability of the tractor to perform the specified functions established by regulatory requirements. The basis for the formation of the limiting values of the functional indicators of the developed tractor are the characteristics of the basic samples and analogues, the requirements of national and international standards, technical conditions, materials of research and development work, customer reviews, and others. The functional indicators of the tractor determine its technical level, which can be assessed using well-known methods. Conclusions. As a result of the study, the dependence of the tractor's performance on its movement speed, stability of the direction of movement and braking was substantiated; the basics of ensuring the operability of a tractor at all stages of its life cycle are considered: creation, production, circulation, operation, disposal. The scientific value of the study lies in the substantiation of the methodology of a systematic approach to assessing the performance of a tractor at the stages of its life cycle. The practical value of the study lies in the ability to predict the performance of a tractor at any stage of its life cycle, starting with design and analyzing the state of the tractor during its disposal, in order to improve performance in future design. The research results can be applied in the design, manufacture and testing of tractors, as well as in the field of their operation to assess the possible resource. Further research is required to predict the performance of tractors at the test stage.

EXPERIMENTAL STUDIES OF A MODEL FOR OPTIMIZING THE PORTFOLIO OF A PROJECT-ORIENTED ORGANIZATION BASED ON THE ENTROPY CONCEPT

The subject of the research is the optimization of the composition of the project portfolio based on the entropy concept. The aim of the study is to experimentally test the model for optimizing the portfolio of a project-oriented organization and substantiate its applicability in practice in management processes to ensure their effectiveness. Research objectives: forming a model taking into account the accepted value of the organization; formation of initial data on the organization and alternative projects; portfolio optimization by model and interpretation of results. Research methods: system analysis, functional analysis, operations research. Results. A model has been developed for forming a portfolio structure from projects of two categories – operational and development; the optimization criterion is to minimize the discrepancy between the desired and actually provided value of the organization. The restrictions take into account the maximum allowable energy limit and the minimum allowable value limit. As a result of the study, the applicability and adequacy of the model for optimizing the portfolio structure of a project-oriented organization were substantiated. The model makes it possible to obtain solutions on the optimal structure of a portfolio of projects in terms of its value under given resource constraints (in the form of a share of total energy and output energy) and energy entropy. The studies substantiated the possibility of adjusting the model in terms of the optimization criterion (maximizing value, minimizing energy entropy) and adding restrictions on the maximum permissible border of information entropy and energy efficiency. Conclusions. The model under consideration is characterized by wide practical application, taking into account its possible adjustment without changing the basic essence, taking into account the specifics of a particular field of activity or organization. The practical use of the main indicators of the entropy concept - information entropy, temperature, energy entropy, which characterize the state of organizations, allowing to identify hidden problems before they are reflected on the traditional indicators of organizational performance is demonstrated. Taking this into account, the structure of the project portfolio is being formed within the framework of the considered approach.

Оценивание состояния растительности на основе аппарата нечёткой логики

Assessment of forest vegetation is based on multispectral space imagery processing. The issues of the formation of initial data and selection of test sites for automated identification of landscape elements are considered. The aim of the work is to present an assessment technology for natural objects that applies the mathematical apparatus of fuzzy logic to automated processing of multispectral aerospace imagery. An example of assessing the forest state and determining the consequences of a forest fi re is presented.

Formation of initial data when planning for custom manufacturing

The formulation of the problem of production planning for custom small-scale electronic production is considered. In order to increase the efficiency of solving automation planning problems, an approach has been developed to generate optimal initial data for planning, taking into account their dimensionality. An improvement in the execution time of production plans at the first stage of manufacturing an order by an average of 5-10% is shown.

The approach to the evaluation of options of the activities of the operators technical support information services telecommunication systems

The purpose of the article is the development of formalized models and algorithms for estimating the activity of operators working in telecommunication systems, specializing in providing IT services to the population and companies. The generalized structural method of the functional and structural theory of ergonomic and technical systems of professor A. I. Gubinsky is chosen as a basic solving method. The method is based on the use of standard functional units to describe the algorithms of activity. These units are presented in the form of functional networks. A number of formalized descriptions of algorithms of the operators’ activities for elimination of some problems of IT services providing is developed. The calculations of probability of timely and faultless execution of the activities algorithm for the elimination of one of possible problem situations are performed. The technology of the account at an assessment of reliability of activities for elimination of problems is shown. This technology considers such parameters as activity algorithms, operators’ qualification and working conditions at the workplaces. The advantage of the method consists in a possibility of receiving the unambiguous computer focused models and numerical estimation of various options of operators’ activities, who have different qualification. Using the proposed approach allows to develop the actions related to the search of ergonomic reserves of systems efficiency increase of providing access to resources of computer networks. The developed models can be the basis for decision support system for the optimization of operators’ activities. The difficulties of the method include the complexity of formation of initial data for the calculation and the necessity of supporting special statistical databases, also the need of systematic assessment of working conditions at the workplace of people working in the system