A Generalized Approach to the Analysis and Design of Microwave Bandpass Mutually Detuned Resonator Filters /Ilchenko M.E., Zhivkov A.P. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Microwave bandpass mutually detuned resonator filters in the parallel channels are fundamentally different from traditional filters cascaded resonator tuned to the same frequency – the connection between the resonators in them is essentially absent because of both the parallel mutual position relative to the direction of propagation, and the mutual detuning frequency. Therefore, the traditional methods of analysis and design using the ladder diagrams of low-frequency counterparts cannot be applied.
Objective. Creating models of microwave bandpass mutually detuned resonator filters in the parallel channels based on the low-frequency counterparts.
Methods. Analysis of all known publications devoted to the microwave bandpass mutually detuned resonator filters in parallel channels allowed to reveal inherent patterns (types of oscillations in parallel channels, the location of the poles of attenuation above or below the bandwidth), manifested regardless of the types of resonators.
Results. The analogy between the characteristics of the microwave bandpass mutually detuned resonator filters in parallel channels and low frequency of prototypes based on bridging bandpass filters is established.
Conclusions. To simulate microwave bandpass mutually detuned resonator filters in parallel channels, low-frequency prototypes based on bridging bandpass filters can be used, design techniques of which are well specified.
Keywords: bandpass filters; microwave.
Development of Fuzzy Situational Networks with Time Constraints for Modeling Dynamic Systems /Gozhyj O.P. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Fuzzy situational approach and decision support systems developed on its basis with the use of fuzzy logic are effectively applied for solving the situational modeling problems and decision making. The fuzzy situational networks provide a possibility for solving the dynamic situational modeling problems and making control decisions with taking into consideration special features of the situations and possible time constraints.
Objective. The main goal of the study is development and investigation of the fuzzy situational networks with time constraints aiming to solving the problems of complex dynamic systems modeling, and implementation on their basis of decision support systems for solving the problems mentioned.
Methods. The special features of the fuzzy situational networks with time constraints development process are considered. In the development of the fuzzy situational networks the time constraints create conditions for the transitions between situations. The time constraints are usually set in absolute scale. The fuzzy situational systems with time constraints provide a possibility for deeper study of the situations due to increase of the control decisions quantity.
Results. The main results of the study are as follows: we proposed the methodology for constructing the fuzzy situational networks and an illustrative example of its application to solving the problem of control for unmanned aerial vehicles. To develop the fuzzy situational networks with time constraints a special decision support system was developed and tested.
Conclusions. The use of the dynamic description for control situations provides a possibility for more detailed description of the structure and content of the system under study as well as to decrease the number of reference satiations due to deeper investigation and increase of control decisions. The use of time parameters in the descriptions increases the effectiveness of fuzzy situational networks as an instrument for situational simulation.
Keywords: fuzzy situation; fuzzy situational network; time constraints; reference situation; control actions; decision support system.
Completeness Problem in Preserving Denotations Function Class on Records /Zakharchenko T.L., Redko I.V. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Modern range of IT problems forces researchers to not only consider solutions of programmers’ problems, but processes of their solution. That is why researches of generally valid organization structures of the processes become the most important. Distinct place in the researches take problems related with building of algebraic characteristics of pragmatically-conditioned function classes, including completeness problems solutions in corresponding algebras.
Objective. Solution of completeness problem for class of computable manipulative functions on records. Term “manipulative” is specified as property of function to preserve denotations (atomic elements, which form records).
Methods. Primitive program algebra (PPA) has been chosen as instrument for the research of this class of computable functions. Solution of PPA completeness problem for manipulative functions on n-tuples formed solution basis of completeness problem and basis of generative functions system creation. Buildings, made in the paper, are based on algebraic methods of program analysis and methods of compositional programming.
Results. Solution of completeness problem for class of computable manipulative functions on records is described.
Conclusions. Results yielded may be utilized for further theoretical and applied researches of record manipulation methods, uncovering algebraic characteristics of manipulation functions classes on perspective carriers, for instance, lists, stacks, queues etc., programming languages semantics formalization, which use records as data type.
Keywords: completeness problem; denotations; primitive program algebras.
Approach for Solution of Nonlinear Optimization Problems with Blocks Structure and Coupling Constraint /Kirik O.E. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Non-linear optimization problems for the operation of large space or functionally distributed systems with independently functioning subsystems and restrictions on some of the common resources are considered.
Objective. The aim is to build an effective approach to solving nonlinear optimization problems of block structure with coupling constraints on the basis of the combination of approximating nonlinear optimization methods and decomposition techniques.
Methods. The three-step iterative scheme has been proposed. On the upper level the original problem is replaced by a sequence of approximating problems with additively-separable objective function and linear constraints. On the second level, coordinating problems, which are formed by the information received at the lowest level from local block problems, are solved.
Results. The algorithm, which is a combination of the linearization method of B.Pshenichniy and the dual decomposition, has been built. The structure of the dual coordination problem has been described. Estimation of the convergence rate has been carried out.
Сonclusions. The proposed approach and the algorithm constructed based on it can be applied to a wide range of problems associated with optimal allocation of limited resources in the large block-structured systems.
Keywords: resource distribution problems; optimization models; non-linear programming methods; decomposition algorithms.
Method of Constructing Type-2 Fuzzy Models with Interval Membership Functions for Diagnostic Systems /Kondratenko N.R. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Presently, the amounts of data accumulated by researchers in different areas of human activity are increasing dramatically due to rapid development of information technologies. The question of data analysis and knowledge presentation in decision support systems under uncertain conditions is important, namely detecting hidden rules and dependencies; extracting, presenting and processing of incomplete knowledge obtained with the help of experts, or knowledge, obtained as a result of experimental data processing. Since knowledge obtained from experts usually contains different kinds of uncertainty, it is important to look for methods that enable presentation and processing of incomplete or almost contradictory information. Methods of fuzzy set theory are the most suitable for processing of such data.
Objective. Improving the subject area reflection quality by implementing the method of generating type-2 fuzzy models with redundant knowledge bases.
Methods. The implementation method is directed at using redundancy of the fuzzy knowledge base. The knowledge base is built based on experimental data that is used to determine centers of the rules’ antecedents and consequents fuzzy sets. The given approach enables creating a fuzzy knowledge base in reasonable time. In order to build a fuzzy model with some of the values missing in the rules included into the knowledge base by an expert, and with partially missing experimental data, methods of generating fuzzy models based on type-2 fuzzy sets with partial experimental data are introduced. A fuzzy model is represented as an interval type-2 model with interval membership functions. Redundancy reduction and missing input data processing are implemented using optimization procedures. The quality of reflection of input values into output values is analyzed using a fuzzy models functioning quality criterion.
Results. A research of fuzzy type-2 models built using the given method is shown. On an example of a medical diagnostics problem the main parameters of the generated fuzzy models are given, and values of their performance criteria are calculated.
Conclusions. A method for generating type-2 fuzzy models with interval membership functions was developed, which includes rules built based on experimental data, and which provides the capabilities for taking an expert’s opinion into account. As part of the given method it is suggested to use the main and the secondary criteria to assess type-2 fuzzy models performance quality. These two criteria enable the developer of an expert system to make the right choice of the fuzzy model that describes the subject area in the most adequate way.
Keywords: type-2 fuzzy model; interval membership function; redundant knowledge bases; expert; quality criteria.
Business Intelligence Techniques for missing data imputations /Kuznietsova N.V., Bidyuk P.I. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Properly constructed decision support systems (DSS) for modelling and forecasting behaviour of dynamic systems provide a possibility for taking into consideration uncertainties of probabilistic, statistical and structural types what results in higher quality of developed models and estimated forecasts.
Objective. To consider general reasons for loosing (missing) data in statistical data analysis; to provide categorization of missing data into several groups, and identify the reasons for missing measurements; to provide stepwise system methodology for uncertainty analysis and selection of data imputation techniques; to give an insight into some popular missing values imputation techniques regarding their possible applications.
Methods. To solve the problems mentioned the following methods have been used: data categorization approach from business or practical point of view that is necessary for discovering the reasons for availability of systemic and/or random missing values; the modern systemic methodology was hired for analysis of uncertainty causes and missing values imputation; the decision tree based imputation procedures; EM algorithm and regression model approach to forecasting missing data using forecasting functions.
Results. The main results of the study are in categorization of the missing data into groups; development of systemic methodology for analysis of uncertainty causes and missing values imputation; providing an analysis for possibilities of missing values imputation with decision trees, EM algorithm and regression models; development of multistep forecasting functions on the basis of autoregression models; illustration of application of some selected perspective methods for missing data imputation.
Conclusions. We proposed the six steps system methodology for data imputation which stresses that selection of correct method for imputation is tightly connected with the step-by-step analysis of the gaps causes and finding an appropriate technique for their imputation. The results of imputation sometimes are rather far from the existing data and should be smoothed or even broken from the sample due to their incorrectness. For such cases it should be proposed a new probabilistic-regression method which allows define parameters of the probability interval for the regression aiming missing data imputation. A series of computing experiments performed with EM algorithm, forecast regression based imputation technique and some other approaches shows that it is possible to reach high quality results regarding correct processing of data with missing values.
Keywords: uncertainties in data processing; imputation of missing data; systemic approach; decision support system.
Automation of Impulse Processes Control for Cognitive Models with Delays /Romanenko V.D., Milyavsky Y.L. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. The paper deals with the problem of cognitive modelling, namely control of complex systems with dynamics in impulse process presented by cognitive maps. It is assumed that the systems operate with delays that may occur either between vertices coordinates of a cognitive map or during transmission of control signals.
Objective. Build models of cognitive maps with different delays and to apply these models to control impulse processes in cognitive maps.
Methods. The article discusses two approaches for delays – control delays and delays during interaction between the vertices of a cognitive map. For the first case, a control algorithm based on reference model of a closed system was proposed, for the second case it is based on quadratic optimality criterion. Obtained results were verified using cognitive maps of commercial bank and health care system. Different delays were included into these systems and control laws were developed.
Results. Simulation results have confirmed that proposed methods reach the objective, i.e. they allow stabilising system with delays in impulse mode.
Conclusions. Research provided in the paper extended the class of controlled cognitive maps by systems with delays.
Keywords: cognitive map; impulse process; system with delays; control algorithm.
Development of Bending Automatic Die-Casting Department /Bogushevsky V.І., Antonevych Y.К., Antonevych О.О. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. The main development direction of the foundry at the present stage is its intensive upgrade based on flexible automatized manufacture, including flexible automated lines and flexible automated shops (FAS). Creating of FAS became possible thanks to the emergence of robots and technological systems, the introduction of microelectronics and computer technology in control and management device.
Objective. Analyze the known process control systems, and to develop flexible automated die-casting station.
Methods. The PC simulation method, parameters calculation and design of flexible automated modules were used.
Results. On the basis of information ACSTP of die-casting complex designed ACS of flexible die-casting line to coordinate in real time technological and production processes with continuous-discrete character of the passage. The basic characteristics are given, information and control system functions are provided, algorithms, and the scheme of the site and its parts are described.
Conclusions. FAS implementation shows their high efficiency: labor costs for making castings are reduced by 1.5–1.8 times, cycle times and the number of employees are reduced.
Keywords: flexible automated line; mathematical model; transportation and manufacturing operations; casting.
Influence of Intermediate Ag Layer Thickness on Phase Transformations in FePt/Ag/FePt Thin Film Compositions /Vladymyrskyi I.A., Kruhlov I.O., Verbytska M.Iu., Fihurna O.V. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Film compositions with chemically ordered and magnetically hard L10-FePt phase are the perspective materials for ultrahigh density magnetic recording. The deposition on heated substrate or providing an annealing is required for L10-FePt phase formation. However, heat treatment causes the grains growth and increase of surface roughness of the films, which complicates the practical use of these materials. The introduction of intermediate layers of “third” elements between FePt alloy layers is one of the possible solutions of this problem, which can reduce the temperature ofА1‑FePt ® L10‑FePt phase transformation.
Objective. Investigation of the influence of intermediate Ag layer thickness on the structure and magnetic properties of FePt/Ag(7.5; 30 nm)/FePt compositions.
Methods. Film compositions were obtained by magnetron sputtering, structure and properties before and after heat treatment were investigated by X-ray diffraction, atomic force microscopy, magnetometry and resistometry.
Results. It is determined that increasing of Ag layer thickness from 7.5 nm up to 30 nm leads to a reduction of the L10-FePt phase formation temperature for ~ 100 K and to an increase of the compositions coercivity.
Conclusions. A possible explanation for the phenomenon of L10-FePt phase formation temperature reduction with increasing Ag intermediate layer thickness lies in the difference between the stress states that occur in these films during annealing due to differences in linear expansion coefficients of their layers. The thickness increase of the intermediate Ag layer increases the composition coercivity as a result of saturation of the grain boundaries of the L10-FePt phase with non-magnetic ingredient and limitation of the exchange interaction between the grains.
Keywords: magnetic recording; film compositions; FePt; coercivity.
Surface Microgeometry and Surface Layer Condition of Wear-Resistant Parts of High-Friction Composites for Abrasion Superfinishing /Gavrish А.Р., Roik Т.А., Lototska O.І., Vitsiuk Yu.Yu. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Microgeometry surface features of wear-resistant friction parts of new composite alloys 11Р3АМ3Ф, 85Х6НФТ, 4ХМФТС, Р6М5Ф3, and 4Х2В5МФ, which contain such chemical elements as titanium, wolframium, molybdenum, and vanadium with CaF2 increments and its influence on quality parameters.
Objective. The purpose of this paper is to determine the quality parameters provided for superfine superfinishing of machine systems friction parts, which contain such chemical elements as titanium, wolframium, molybdenum, and vanadium with CaF2 increments and studied the influence of abrasive superfinishing quality parameters and surfaces of friction precision.
Methods. Surface treatment of high-alloyed friction parts based on die steel and tool steels wastes with abrasive superfinishing.
Results. The research results of thin technological processes of superfinishing and formation of the surfaces parts, which were manufactured of new composite materials on the base of die steel and tool steels wastes and which contain such chemical elements as titanium, wolframium, molybdenum and vanadium were presented in the article. It was defined that the dependence of the quality of composite parts surface is determined by composition of the abrasive hones, their grain, bond type of superfinishing tools and parameters of cutting. These recommendations meet the quality requirements of the friction surfaces of working surfaces of parts. Recommendations for the choice of the abrasive hones for industrial engineering companies have been developed.
Conclusions. It was shown that high quality parameters of friction surfaces of the parts, for example, the pressure tensions and micro-hardness of the surface layer and other quality parameters are formed as result of interaction between cutting modes and friction-polishing by abrasive hones and such factories as granulocyte and properties of abrasive tools for the fine superfinishing technology. Also was shown that the best results can be achieved with using hones on the base of green carbid cremnium on the elastical gliftalical bond with the abrasive grit 7–14 mkm (63CM7CM2Гл, 63CM14CM2Гл) and thin parameters of cutting.
Keywords: new composites; superfinishing; abrasive hones; cutting mode; quality surface.
Alignment of Inertial Navigation System Using PID-Control /Avrutov V.V., Stefanyshyn Z.S. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Alignment of inertial navigation system has vital importance to inertial navigation system, because precision navigation depends on the process time and alignment error.
Objective. The purpose of our paper is to research possibility to use PID-control for initial alignment of inertial navigation system. Two alignment modes – leveling and gyrocompassing of platform are discussed.
Methods. Literature review on alignment and state of problem are considered in the first part – introduction. The second part of the paper presents details of standard gyrostabilized platform leveling by scheme “accelerometer–gyroscope–platform”. In the third part a possibility to use PID-control for coarse leveling by “accelerometer–platform” scheme is discussed. Gyrocompassing mode is the subject of the last fourth part.
Results. Calculation formulas for determining the coefficients of the PID control, dynamic and precision characteristics of gyrocompassing mode for gyroscope proportional control law are obtained. The results of computational modeling of the process of leveling for multiple selection criteria of the coefficients of the PID-control are brought.
Conclusions. It is concluded that using of standard Butterworth forms and integral criterion of minimum weighted error module allows us to bring and provide the necessary precision. Using the PID-control for the coarse leveling mode ensures the necessary control process quality.
Keywords: inertial navigation system; gyroscope; accelerometer; gyrostabilized platform; alignment; gyrocompassing; PID-control.
Systematic Error of the Optical Spectrum Analyzer /Kolobrodov V.G., Tymchik G.S., Kolobrodov М.S. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Coherent optical spectrum analyzers are widely used in information processing systems. The principle of operation of spectrum analyzers is based on the scalar theory of Fresnel diffraction, which approximately describes the propagation of light in the paraxial range. This article examines the systematic error of the optical spectrum analyzer, which is caused by the Fresnel approximation.
Objective. The aim is the investigation of the optical spectrum analyzer systematic error, which is caused by the Fresnel approximation, to determine the allowable errors of measurement of the spatial frequency of the signal spectrum.
Methods. On the basis of physical and mathematical model of coherent spectrum analyzer systematic error in determining the spatial frequency is investigated, which arises as a result of the transition from the propagation of light in free space to the Fresnel diffraction.
Results. An equation for calculating the absolute and relative measurement errors depending on the angle of diffraction of light is obtained, which allowed us to determine the limits of the spectral range for a given relative error of measurement of the spatial frequency. It is found that the Fresnel approximation within the diffraction angle from 0° to 10 ° provides a relative error less than 1,5 %. At the same time at a diffraction angle of 20°, it is 6,4 %.
Conclusions. There are fundamental limits to investigation of the application limits of the scalar theory of Fresnel diffraction, which determine the spatial range, where is the Fresnel equation. At the same time, there is no investigation of the optical spectrum analyzer systematic error, which is caused by the Fresnel approximation. An equation for the absolute systematic error of measurement of the spatial frequency, depending from elements parameters of the spectrum analyzer is obtained. This equation can be used to optimize the parameters of the spectrum analyzer, as well as to compensate for systematic error by the computer processing of the output signal of the spectrum analyzer.
Keywords: optical spectrum analyzer; Fresnel diffraction; spatial frequency; frequency measurement error.
Conceptual Basis of Adaptive Autopilots /Teut V.M. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. The paper is devoted to critical analysis of literature that covers the major aspects of adaptive ship motion control systems.
Objective. The objective of a study is identifying the promising areas of research in the field of adaptive ship motion control.
Methods. The analysis of existing approaches to ship model parameters identification (including identification during zig-zag motion, during circulation and identification using Kalman filtering) is done; advantages and disadvantages of those methods are determined. The methods mentioned can be used as a basis for creating adaptive gyropilots. A critical review of approaches to ship control by means of classical and modern methods of automatic control, including the parametric adjustment of classic PID regulators, switching of regulators, use of nonlinear regulators – linear-quadratic (LQ), sliding mode regulators, and artificial intelligence – neural networks, fuzzy logic and hybrid approaches, is done. Separately, in the survey analysis of papers of Ukrainian authors, which are devoted to the development of adaptive gyropilots and adaptive ship motion control, is presented.
Results. As a result of literature survey, prospective areas of studies in the field of adaptive ship control are determined.
Conclusions. Most promising research areas are:
1) development of novel approaches to the identification of the vessel model parameters and disturbances acting on it;
2) application of artificial intelligence, including fuzzy logic and neural networks, to adaptive ship control methods;
3) development of adaptive nonlinear systems for ship motion control.
Keywords: adaptive ship motion control; adaptive gyropilot; ship model parameters identification.
The Material Balance Calculation of Flowsheet for Nitrate Removal from Water Solutions Using Baromembrane Methods /Iievlieva O.S., Goncharuk V.V. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. The high level of nitrate contamination in natural water is one of the main problems in environmental studies. The two-stage flowsheet is offered for solving this problem. It has a lot of advantages but needs to consider the feasibility of its using in each individual case.
Objective. The calculation of material balance of the proposed scheme allows us to determine the all ions concentrations and flows (volume) of water at all stages of the process.
Methods. The filtration process of a nitrate solution or natural water with previously added reagent was carried out in the two direct flow laboratory cell: for nano-and ultrafiltration.
Results. Obtained formulas allow easily calculate all the volumes and concentrations and make conclusions about the expediency of the scheme in each case. The experimental verification of the proposed scheme for purification the natural water from an underground source, where the nitrate concentration was 105 mg/dm3, proved the its effectiveness for the selective removal of nitrate ions from natural water.
Conclusions. The obtained material balance allows us to estimate the feasibility of practical implementation of the two-stage process flowsheet for the nitrate removal from natural water using baromembrane methods and to control the purification process on each stage. The prospects of the scheme is in the solving the important environmental problem which concerns the purification of the natural water with high level of nitrate.
Keywords: nitrate ions; natural water; removal; nanofiltration; ultrafiltration; polyhexametylenguanidyn.
One-Dimensional Tin (IV) Oxide Nanostructures as Gas-Sensing Materials /Nagirnyak S.V., Dontsova T.A., Astrelin I.M. - K. Naukovi visti NTUU “КPІ”. – 2015. – N 3. – P.
Background. Gas sensors based on SnO2 are characterized by small size and low cost. However, its significant disadvantages are insufficient sensitivity, small selectivity and low stability. Therefore, the determination of basic parameters, a change that will create effective, highly sensitive and selective semiconductor sensors based on SnO2 nanostructures, is extremely important.
Objective. The purpose of this paper is to establish the main parameters affecting the sensitivity, selectivity and stability of semiconductor sensors.
Methods. A critical review of recent scientific literature is done. Found that the usage of 1D tin (IV) oxide nanostructures (as pure and doped) will increase the sensitivity and selectivity of the metal oxide sensors due to high values of surface to volume ratio and the creation of active centers in relation to the detected gases.
Results. It was determined that the creation of efficient and sensitive semiconductor sensors requires the use of 1D SnO2 nanostructures and their directed modification by various additives.
Conclusions. In terms of data presented in contemporary scientific literature, to create effective semiconductor tin (IV) oxide based sensors 3S parameters of these sensors need to be improved. From this point of view, 1D SnO2 nanostructures deserve special attention due to the totality of their physical and chemical properties. Vapor transport method (method CVD) is enough effective for the synthesis of 1D nanostructures. It secures superior performance in conjunction with relative simplicity and availability. And this method allows us to obtain single-crystal nanostructures of controlled morphology. However, as of day there is no almost information on the impact of operational parameters of CVD synthesis on physico-chemical characteristics of obtained nanosized SnO2. Therefore, the advanced study of scientific bases of purposeful synthesis and systematization of approach in the selection a dopant to increase selectivity of metal oxide gas sensors is the main task.
Keywords: semiconductor sensor; tin (IV) oxide; one-dimensional nanostructures; vapor transport method; additive.