bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal control of fractional semilinear PDEs
Authors: Antil Harbir , Warma Mahamadi
Published: January 2019

In this paper, we consider the optimal control of semilinear fractional PDEs with both spectral and integral fractional diffusion operators of order 2swiths∈ (0, 1). We first prove the boundedness of solutions to both semilinear fractional PDEs under minimal regularity assumptions on domain and data. We next introduce an optimal growth condition on the nonlinearity to show the Lipschitz continuity of the solution map for the semilinear elliptic equations with respect to the data. We further apply our ideas to show existence of solutions to optimal control problems with semilinear fractional equations as constraints. Under the standard assumptions on the nonlinearity (twice continuously differentiable) we derive the first and second order optimality conditions.
Research of efficiency of the statistical non-parametric pattern recognition models for forest land classification
Authors: Guk Aleksander P. , Evstratova Larisa G.
Published: January 2019

The principles of the creation of pattern recognition models, based on using multispectral imagery of forest land, have been analyzed. The statistical non-parametric model has been suggested as a basic pattern recognition model and the probability density function - as a recognition feature. Efficiency of the different quality criteria has been discussed. The main directions for improving the pattern recognition models are regarded.
Multi-version approach to improve the reliability of processing data of the earth remote sensing in the real-time
Authors: Saramud Mikhail V. , Kovalev Igor V. , Losev Vasiliy V. , Petrosyan Mariam O. , Kovalev Dmitriy I.
Published: January 2019

The article describes the use of a multi-version approach to improve the accuracy of the classification of images when solving the problem of image analysis for Earth remote sensing. The implementation of this approach makes it possible to reduce the classification error and, consequently, to increase the reliability of processing remote sensing data. A practical study was carried out in a multi-version real-time execution environment, which makes it possible to organize image processing on board of an unmanned vehicle. The results confirm the effectiveness of the proposed approach.
Dynamic texture recognition under adverse lighting and weather conditions for outdoor environments
Authors: Pyataeva Anna
Published: January 2019

Recognizing dynamic patterns based on visual processing is significant for many applications. In this paper dynamic texture recognition focuses on outdoor scenarios where a crisis event might occur (i.e. fire in a forest, floods/flooding etc.) Real outdoor scenes may include the objects with dynamic behaviour due to illumination, blurring, or weather conditions effects. Under bad weather conditions the imaging systems is degraded and produce low visibility images. In this work precipitation artefacts and lightning effects for dynamic texture analysis were studied. Experimental results show that the proposed method of weather and adverse lighting effects compensation is feasible and effective for videobased dynamic texture analysis under bad weather conditions.
Simulated satellite imagery of lengthy territories with complex configuration
Authors: Mozgovoy Dmitriy , Svinarenko Dmitriy , Tsarev Roman , Yamskikh Tatiana
Published: January 2019

The study presents the results of creating simulated satellite imagery of lengthy territories with complex configuration using data from satellites with optical-electronic scanners of ultrahigh spatial resolution. The article attempts to clarify the feasibility of one-orbit imagery of a given lengthy object, taking into account the existing limitations on the values of pointing angles and satellite angular velocities based on the results of modeling the system of automatic satellite attitude program control during the process of imagery.
Experience of the application of remote sensing data in the problems of geo-ecological monitoring of the coal mining area
Authors: Giniyatullina Olga , Schastlivtsev Evgeniy , Kovalev Vladimir
Published: January 2019

The experience of solving problems of geoecological monitoring of coal mining region with the use of remote sensing data is presented. The results of control over the boundaries of coal-mining enterprises, assessment of the degree of self-growth of dumps, monitoring of the state of vegetation near objects of coal mining and dust load of the area are shown.
Estimation of forest cover restoration damaged by Siberian silkmoth using remote sensing data and maps
Authors: Fedotova Elena
Published: January 2019

The current state of the land cover has been estimated in the territories where in different years (1885, 1955, 1995) the forests were damaged by Siberian silkmoth. Dark-needle taiga is restored through the change of tree species. In 20 years in areas of dark-needle taiga there are graminoid communities, in 60 years we have deciduous forests there, and in 130 - dark needle forests, but not everywhere.
Studying the thermal field dynamics in the forest harvesting sites
Authors: Khamedov Vladimir
Published: January 2019

The article presents the results of the investigation of thermal field dynamics in the forest harvesting sites with the Landsat 8 satellite images in a long Infrared range. The temporary (annual and seasonal) dependences of the forest floor temperature in the harvesting sites are studied. The dependence of the forest floor temperature condition in the harvesting site on the area of the site is considered. The method to detect the sites strewn with the forest residues by using the images in a near Infrared range is described.
Droplet desorption modes at high heat flux
Authors: Misyura Sergey , Meleshkin Anton
Published: January 2019

Nonisothermal droplet desorption of aqueous salt solution H2O/LiBr during nucleate boiling was studied experimentally. A droplet was placed on a horizontal heated wall. The initial concentration of salt C0= 25 %. The wall temperature Tw= 120 °C and ambient air pressure is 1 bar. Thermal images of the temperature field on the droplet surface show an extremely non-uniform temperature field. At nucleate boiling in LiBr salt solution it is incorrect to predict the desorption behavior in stationary approximation. It was previously believed that the rate of evaporation does not vary with time. For the first time it is shown that the desorption rate is divided into several characteristic time intervals. These intervals is characterized by a significant change in the desorption rate.
Numerical and physical modeling of heat transfer in the exhaust system of a piston engine in stationary conditions
Authors: Plotnikov Leonid , Nevolin Alexandr , Misnik Mariya
Published: January 2019

Thermomechanical perfection of exhaust systems largely determines the efficiency of the engine boost system. The article presents the results of numerical simulation and experimental study of heat transfer of gas flows in profiled exhaust systems of ICE. The description of the numerical simulation technique, the experimental setup, the configurations of the hydraulic systems under investigation, the instrumentation and the experimental features are given in the article. On the basis of numerical simulation, it has been established that the use of profiled sections with a cross-section in the form of a square in the exhaust system of an ICE leads to a decrease in the heat transfer rate to 5 %. The use of profiled sections in the form of a triangle in the system under consideration causes a more significant decrease in heat transfer, which reaches 11 %. Experimental studies qualitatively confirm the results of simulation.
Nonstationary gas-dynamics and local heat transfer in the output channel of the turbocharger compressor
Authors: Plotnikov Leonid , Grigor'ev Nikita , Kochev Nikolaj
Published: January 2019

Thermomechanical characteristics of the gas flow at the turbocharger compressor outlet largely determine the quality of the intake process in piston engines with boost. The article presents the results of an experimental study of gas-dynamics and heat transfer of gas flows after compression in a turbocharger centrifugal compressor. A brief description of the experimental setup, the configuration of pipes under investigation, the measuring system and the experimental features are given. The studies were carried out on a free compressor, i.e. without considering the piston part. Different conditions in the compressor outlet channel were created by installing special nozzles with different hydraulic resistances. It has been established that the local heat transfer increases from 23 to 46 % with an increase in the turbocharger rotor speed, depending on the outlet channel configuration. It should be noted that an increase in rotor speed is also accompanied by an increase in air flow through the channel. The increase in flow rate was from 10 to 42 %.
Physical modelling of the motion of a liquid metal melt along the surface of a heated rod
Authors: Lobanov Pavel D. , Usov Eduard V. , Klimonov Ilya A. , Kutlimetov Alexander E. , Butov Anton A. , Chukhno Vladimir I. , Kudashov Ivan G. , Svetonosov Alexander I. , Pribaturin Nikolay A.
Published: January 2019

The investigation of the melt flow of a liquid metal along the surface of a heated rod is carried up. In the experiments, the metal from the upper volume was drained over the surface of a quartz tube, heated from the inside. This pipe is used to simulate a fuel column. A high-speed video of the process was produced. Data are obtained on the features of the flow of a metal melt. The stages of formation of droplets are shown. The data on the shape and velocity of the droplet movement are given. It is shown that in the air atmosphere around the test section when the first drop passes on the surface of quartz, a trace is formed, along which the metal moves in the future. Direct and curvilinear rivulet flows on the rod's surface are also observed.
Synthesis of Hf-C-N ceramics by spark plasma sintering
Authors: Zavjalov Alexey , Papynov Evgeniy , Shichalin Oleg , Nikiforov Pavel , Goncharov Evgenii
Published: January 2019

We obtained the Sample by the spark plasma sintering (SPS) of commercially available HfC and HfN powders. The identification of obtained material was carried out by the X-ray diffraction and the Raman spectroscopy. The solid solution of previous material was confirmed. However oxide phase excreted wile sintering presumably duo to oxygen impurities of used commercially powders.
The optimal composition of reagents for producing aluminosilicate glue based on fly ash of thermal power plants
Authors: Temnikova Elena Yu. , Lapin Alexey A. , Bogomolov Alexander R.
Published: January 2019

The work is devoted to the processing of fly ash wastes obtained from coal combustion. Based on the non-magnetic fraction of fly ash (its particle size of 0-50 μm), an aluminosilicate glue or liquid glass as a cementing component has been obtained. It was represented by a number of silicate modules (SiO2/Me2O molar ratios): 2, 2.5 and 3 (for three different formulations). The shear deformation tests for glued plates with glues of various silicate modules have been carried out. The shear stresses for the samples with silicate modules of 2.0, 2.5, 3.0 were equal to 48, 66 and 34 kPa, respectively. These results suggest that during the production of aluminosilicate glue, the silicate module of 2.5 is more favored for providing the strongest bond between ceramic tiles.
The effect of increasing gas shear on wave structure of thin liquid films
Authors: Isaenkov Sergey , Vozhakov Ivan , Cherdantsev Mikhail , Cherdantsev Andrey
Published: January 2019

Evolution of thin liquid films sheared by co-current gas stream in a vertical 11.7 mm pipe is studied experimentally using BBLIF technique. The main goal is to investigate the transition of wave patterns due to increase in the gas stream velocity, VG, from 0 to 24 m/s. Apart from relatively weak quantitative changes in the characteristics of the primary
waves, replacement of capillary precursor by slow secondary waves is found. The transition is indentified in the range of VG = 8 - 16 m/s for all liquid flow rates. It is observed that the appearing secondary waves may be the main reason of the decay of the capillary precursor. The experimental results are compared to prediction of evolutionary theoretical model, showing qualitative agreement on secondary waves generation, but with no agreement on precursor's disappearance. Introducing artificial perturbations mimicking the action of turbulent pulsations in the gas phase is recommended to improve the model.
Investigation of the effect of carbon nanotubes on electrical properties of woven fiberglass/epoxy composite laminate
Authors: Kalugina Elivazeta
Published: January 2019

The effect of epoxy modified by 0.05 wt. % of CNTs on electrical properties of woven fiberglass/epoxy composite laminate was examined. The electrical resistance was measured using 4-point probe method and LCR-meter during cyclic tensile and fatigue test. Microstructural analysis using field emission scanning electron microscopy (FESEM) was carried out. Based on the experimental data, the increase in load is accompanied by growth in electrical resistance. The change in resistance after 20 cycles was up to 3 %. During fatigue test, the change in resistance was considerable and made up to 25 % in cracking zone of the sample and over 110 % at the failure mode.
Morphology and composition of silica nanowires synthesized on indium and tin catalysts
Authors: Barsukov Andrey , Khmel Sergey
Published: January 2019

Silicon nanowires were synthesized by electron beam plasmaenhanced chemical vapor deposition. The synthesis was carried out using indium and tin catalyst with an average particle size of 100 and 660 nm, respectively, in the temperature range 100-270 °C for indium and 200-335 °C for tin. The minimum (optimum) temperature was found at which an oriented array of microropes was formed. This temperature was 200 °C for indium and 335 °C for tin. In addition, it was found that the formation of individual microropes on the tin catalyst occurred at a temperature lower than the eutectic temperature (232 °C). For indium, this effect was not observed. The silica nanowires synthesized on both catalysts consist of SiOx with x ranging from 1.9 to 2 for all temperatures.
Experimental investigation of wing tip vortices in the near-field
Authors: Stepanov Robert , Pakhov Vladimir , Bozhenko Andrey , Kusyumov Alexander , Mikhailov Sergey , Tarasov Nikolay
Published: January 2019

Results of an experimental investigation related to near-field wing tip vortices are presented. The measurements were carried out using a PIV-system in T-1K wind tunnel of KNRTU-KAI. Q-criterion and crosssectional lines method were used to determine vortex core locations, which showed a good agreement. It is shown that the circulation of tip vortices remains constant at low to moderate angles of attack, and decreases in the stream-wise direction for higher angles of attack. It is also shown that the vortex core radius increases in the stream-wise direction, taking larger values at higher angles of attack.
Experimental investigation of a plate heat exchanger model for lithium bromide absorption chillers: first results
Authors: Stepanov Konstantin , Mukhin Dmitry , Volkova Olga
Published: January 2019

In this paper the results of thermal-hydraulic tests of a sample of a perspective plate heat exchanger under the conditions of LBAHT is described. Working opportunity of the sample working under conditions of LBAHT has been confirmed by this research.
Investigation of the ignition of wood structural materials (with and without fire retardant treatment) under the influence of a model fire of irregular intensity
Authors: Kasymov Denis , Agafontsev Mikhail , Perminov Vladislav , Matrynov Pavel
Published: January 2019

In this paper the effect of fire front on the surface of wood samples (plywood and oriented strand board) was considered to estimate
the effect of different wood-fire retardants. Infrared thermography was used as a diagnostic method. The ignition probability was estimated for the
chosen experimental parameters for each kind of wood The fire hazard characteristics of wood after fire retardant treatment showed a significant
reduction in the surface temperature and the resistance to fire for the chosen parameters of the experiment compared to the same untreated
samples. The charring depth of the wood samples was determined depending on the type of wood, as well as on the type of the fire retardant
used.
Numerical modelling of destruction of a drop of non-Newtonian fluid in a gas flow
Authors: Shebeleva Anna , Minakov Andrey , Lobasov Alexander , Shebelev Alexander
Published: January 2019

The research presents the numerical modeling findings of the secondary breakup of droplets of coal water slurries containing petrochemicals (CWSP) droplet with the filter cake content of 50 % for different Weber number values. The modeling method of the secondary droplet breakup is based on the VOF method for interface resolution, LES model for describing turbulence, and the technology of adapted dynamic grids. This technology enables the grid to be automatically concentrated in the region of large solution gradients during the calculation. The implementation of such a highly detailed grid allowed resolving secondary droplets with the dimensions down to 15 μm. We established the droplet breakup modes depending on the Weber number ranging from 36 to 342. The structure of the stream behind droplets was studied in detail and the numerical method was tested. The results are in good agreement with the results of known experiments.
The flow structure of submerged round jets at low Re numbers
Authors: Lemanov Vadim , Sharov Konstantin , Matyunin Vitaly
Published: January 2019

An experimental investigation of a laminar-turbulent transition in a round jet flowing from a cylindrical tube with a diameter of 3.2 mm have been carried out. The range of Reynolds numbers in the experiments Re = Ud / v were of 700-12000. The measurements have been carried out via the PIV system. The profiles of average velocities and their pulsations in the laminar-turbulent transition zone have been obtained, as well as axial distributions of the longitudinal velocity and longitudinal velocity pulsations. Based on a comparison with the data of other authors, the effect of the initial conditions on the laminar-turbulent transition in a submerged jet has been shown.
The thermal expansion of erbium over a wide temperature range
Authors: Kozlovskii Yurii
Published: January 2019

A dilatometric study results on the linear thermal expansion coefficient (LTEC) of polycrystalline erbium are presented. The experimental data in the temperature range of 100–800 K are obtained. The measurements were made with an error 3%. Approximate dependencies which allow calculating the reference tables of thermal properties for the entire measurement interval are defined.
Method for determining the adhesion force between graphene and copper
Authors: Boyko Evgeny Victorovich , Kostogrud Ilya Alexeevich , Smovzh Dmitry Vladimirovich , Matochkin Pavel Evgenyevich
Published: January 2019

The paper presents the technique of qualitative assessment of the strength of graphene layers adhesion to the surface of a copper substrate, where they are formed. The technique uses a complex of approved analytical methods: electron backscatter diffraction (EBSD), Raman spectroscopy and optical microscopy. The technique was tested on multilayer graphene grown on a copper grain with crystal orientation (111). The presented method can be used to assess the effectiveness of the methods of graphene transfer from grains with different crystal orientation.
Bridge motion of liquid in a gap between the adjacent coils of axisymmetric tubular heat exchanger
Authors: Maltsev Leonid I. , Podzharov Yury S.
Published: January 2019

A model of a liquid bridge, which is formed between adjacent turns of an axisymmetric tubular heat exchanger, has been developed. The shape of the free surface of the bridge cross-section is determined taking into account the forces of liquid ponderability, surface tension, and centrifugal forces. The equations for the coordinates of the points of bridge free surface are presented in an integral form based on the problem solution in the analytical form. The effect of centrifugal forces on the liquid bridge shape and its flow characteristics were analyzed for an axisymmetric heat exchanger, basing on calculations of the shape of the bridge and known data on the speed of the bridge.
Mechanical system detector of weight in motion system
Authors: Nieoczym Aleksander , Drozd Kazimierz , Wójcik Andrzej
Published: January 2019

The multi-sensor and mechanical WIM systems were characterised. The assumption of the necessity of simultaneous analysis of vehicles types (by number of wheels, e.g. two-wheelers, four wheelers, etc.) participating in traffic, was made. This type of analysis involves not only the measurement of vehicle weight but also qualitative detection. Such data are mainly collected and analysed in urban traffic, in which information on traffic volume, lane occupancy or the number of vehicles waiting to enter an intersection are important to ensure continuous, smooth traffic flow. This article presents a design of a WIM system in which the detector is a beam with Bragg grating optical fibre sensors glued on it. Four cases of beam load were determined, due to its strength and the ability to register deformations. The strength analysis of the beam was carried out with the help of MES and its shape was optimised.
Control algorithm for holonomic robot that balances on single spherical wheel
Authors: Wyrwał Daniel , Lindner Tymoteusz
Published: January 2019

This paper presents the control algorithm for the new type of robot that balances on a single spherical wheel. This type of robot is called Ballbot and unlike other statically stable robots, it has a high gravity centre and a very small footprint. The robot is dynamically stable, which means that if the controller stops working, the entire construction will fall over. Because of that, it needs a special control algorithm to keep the balance. The presented Ballbot is fitted with sensors such as gyroscope and accelerometer and controls motors with omni-directional wheels to move the robot in any direction. This paper presents theoretical information about balancing robots and the most important elements of the robot. Next, the design concept of the controller based on STM32 family, control algorithms and filters were proposed and implemented. In the final section of this paper, the investigation results were presented and discussed.
The influence of the Lorenz system fractionality on its recurrensivity
Authors: Gregorczyk Magdalena , Rysak Andrzej
Published: January 2019

In this work, we investigate the recurrensivity of the Lorenz system with fractional order of derivatives occurring in its all three differential equations. Several solutions of the system for varying fractional orders of individual derivatives were calculated, which was followed by an analysis of changes in the selected recurrence quantifiers occurring due to modifications of the fractional orders {q1, q2, q3}. The results of the recurrence analysis were referred to the time series plots, phase diagrams and FFT spectra. The obtained results were finally used to examine the influence of fractional derivatives on the chaos - periodicity transition of the system dynamics.
Towards UML representation for BPMN and DMN models
Authors: Suchenia Anna , Łopata Paweł , Wiśniewski Piotr , Stachura-Terlecka Bernadetta
Published: January 2019

Unified Modeling Language (UML) is a standardised Object Management Group (OMG) notation among software engineers. There have been many attempts to design alternatives to UML. Recently, new notations such as Business Process Model and Notation (BPMN) and Decision Model and Notation (DMN) have been proposed for modelling processes and decisions. These dedicated notations provide a simpler way of capturing functional requirements in a designer-friendly fashion. Moreover, some concepts as rules cannot be directly modelled in UML. Our research considers a method of translating business models such as BPMN and DMN into a set of consistent UML models, which can be later used by business analysts and developers to understand and implement the system. As a single notation design, it allows the user to take advantage of software supporting UML modelling and consistency checking, in addition using such translation can provide additional insights into OMG business models. Furthermore, the design provided in a single notation can be easier to follow and develop. This approach supports also visualisation of rules. It is important to mention that the proposed solution does not extend any custom UML artifacts and can be used with standard UML tools.
Application of Computer System in Control and Programming of a Robotized Soldering Station
Authors: Milecki Andrzej , Regulski Roman , Sędziak Dariusz , Owczarek Piotr , Proch Zbigniew
Published: January 2019

This paper describes a new robotized station for soldering of through-hole elements on printed circuits boards (PCB). The general structure of this station with the SCARA type robot is presented along with the computer-based control system. The software prepared for control and for the programming procedures is described. The developed computer system software, whose structure is also presented, is applied for robot programming. The first main aim is to develop the data retrieval from the Gerber file and to use them to direct soldering robot programming. The second aim of the research presented in this paper is the application of the visual system for pads coordinate recognition. The system is presented and verified.
System for automatic generation of logical formulas
Authors: Klimek Radosław , Grobler-Dębska Katarzyna , Kucharska Edyta
Published: January 2019

The satisfiability problem (SAT) is one of the classical and also most important problems of the theoretical computer science and has a direct bearing on numerous practical cases. It is one of the most prominent problems in artificial intelligence and has important applications in many fields, such as hardware and software verification, test-case generation, AI planning, scheduling, and data structures that allow efficient implementation of search space pruning. In recent years, there has been a huge development in SAT solvers, especially CDCL-based solvers (Conflict-Driven Clause-Learning) for propositional logic formulas. The goal of this paper is to design and implement a simple but effective system for random generation of long and complex logical formulas with a variety of difficulties encoded inside. The resulting logical formulas, i.e. problem instances, could be used for testing existing SAT solvers. The entire system would be widely available as a web application in the client-server architecture. The proposed system enables generation of syntactically correct logical formulas with a random structure, encoded in a manner understandable to SAT Solvers. Logical formulas can be presented in different formats. A number of parameters affect the form of generated instances, their complexity and physical dimensions. The randomness factor can be entered to every generated formula. The developed application is easy to modify and open for further extensions. The final part of the paper describes examples of solvers’ tests of logical formulas generated by the implemented generator.
Neural machine translation system for the Kazakh language based on synthetic corpora
Authors: Tukeyev Ualsher , Karibayeva Aidana , Abduali Balzhan
Published: January 2019

The lack of big parallel data is present for the Kazakh language. This problem seriously impairs the quality of machine translation from and into Kazakh. This article considers the neural machine translation of the Kazakh language on the basis of synthetic corpora. The Kazakh language belongs to the Turkic languages, which are characterised by rich morphology. Neural machine translation of natural languages requires large training data. The article will show the model for the creation of synthetic corpora, namely the generation of sentences based on complete suffixes for the Kazakh language. The novelty of this approach of the synthetic corpora generation for the Kazakh language is the generation of sentences on the basis of the complete system of suffixes of the Kazakh language. By using generated synthetic corpora we are improving the translation quality in neural machine translation of Kazakh-English and Kazakh-Russian pairs.
A* pathfinding algorithm modification for a 3D engine
Authors: Smołka Jakub , Miszta Kamil , Skublewska-Paszkowska Maria , Łukasik Edyta
Published: January 2019

Frequently the quality of a path returned by a pathfinding algorithm is more important than the performance of that algorithm. This paper presents a new algorithm, based on A*, which is better suited for use in 3D game engines. The modification was evaluated by a series of comparative tests. The standard A* algorithm was used as a benchmark in the comparisons. The changes in the algorithm consist in using a different heuristic, adding vertex penalties, and post-processing of the path. A custom-built 3D graphics engine was used as the test environment. The paths generated by the new algorithm are a more natural choice for humans than the ones selected by the standard A* algorithm.
Real-Time Road Quality Assessment Using Smartphones and Cloud Lambda Architecture
Authors: Badurowicz Marcin , Cieplak Tomasz
Published: January 2019

In this paper, the authors are proposing a computer system built in the cloud-computing fashion for the collection of data from smartphones to achieve a crowdsensing-based quality assessment of roads, as well as detection, identification, and assessment of road artefacts (potholes, speed bumps,etc). The proposed information processing methods were based on Lambda architecture and the integration of different types of crowdsourced data to finally calculate the singular value of the human-readable road quality. Finally, the prototype implementation of the system for gathering, processing, integration, and processing the road quality data is also presented.
Impact of feature selection on system identification by means of NARX-SVM
Authors: Awtoniuk Michał , Daniun Marcin , Sałat Kinga , Sałat Robert
Published: January 2019

Support Vector Machines (SVM) are widely used in many fields of science, including system identification. The selection of feature vector plays a crucial role in SVM-based model building process. In this paper, we investigate the influence of the selection of feature vector on model’s quality. We have built an SVM model with a non-linear ARX (NARX) structure. The modelled system had a SISO structure, i.e. one input signal and one output signal. The output signal was temperature, which was controlled by a Peltier module. The supply voltage of the Peltier module was the input signal. The system had a non-linear characteristic. We have evaluated the model’s quality by the fit index. The classical feature selection of SVM with NARX structure comes down to a choice of the length of the regressor vector. For SISO models, this vector is determined by two parameters: nu and ny. These parameters determine the number of past samples of input and output signals of the system used to form the vector of regressors. In the present research we have tested two methods of building the vector of regressors, one classic and one using custom regressors. The results show that the vector of regressors obtained by the classical method can be shortened while maintaining the acceptable quality of the model. By using custom regressors, the feature vector of SVM can be reduced, which means also the reduction in calculation time.
An interactive environment for digital registration of human behaviour for biofeedback purposes
Authors: Szymczyk Tomasz , Baran Katarzyna
Published: January 2019

Unceasing development of computing power of modern computers and advanced graphics card functions enable very faithful projections of the virtual world. However, issues related to real-time object generation and object interaction are complex research problems. A designer and programmer face a dilemma of modifying the model. Simplifying the model significantly affects minimisation of a detail. The article presents a position of digital registration of human behaviour in the virtual world. A study of human behaviour has been proposed, where the main stimulant is not an image but a sound. Participants heard different sounds and responded to them. Parameters such as: pulse, hand movement, general posture and movements of the entire body were registered. An analysis of change in the scope of given psychological modality is important for biofeedback, which allows activating a self-regulatory ability by a body’s feedback. In the authors’ research, depending on variability of a respondent’s reaction, a further interaction with the virtual sound object is created. In this environment, fear of dogs was safely examined. The paper presents the results of pilot studies, which indicated that it is possible to control human reactions by analysing registered parameters, learning to control their own reactions and with more frequent biofeedback training – working out concentration and coping in the most extreme conditions.
Jammers signal power modelling in the Wi-Fi band
Authors: Czerwinski Dariusz , Przylucki Slawomir , Nowak Jaroslaw
Published: January 2019

The distribution of the signal coming from jamming sources is an issue of critical importance to the security and jammer localisation. The paper presents the results of simulations of signal power distribution in the Wi-Fi band conducted for two commercially available jammers, CRJ4000 and CKJ-1502A12. Calculated distributions of signal power were compared with the results from the measurements. The comparison made it possible to assess the correctness of the designed models and out of the simulations. The paper presents the results of simulations and measurements for different scenarios of jammers settings.
Affective computing with eye-tracking data in the study of the visual perception of architectural spaces
Authors: Chmielewska Magdalena , Dzieńkowski Mariusz , Bogucki Jacek , Kocki Wojciech , Kwiatkowski Bartłomiej , Pełka Jarosław , Tuszyńska-Bogucka Wioletta
Published: January 2019

In the presented study the usefulness of eye-tracking data for classification of architectural spaces as stressful or relaxing was examined. The eye movements and pupillary response data were collected using the eye-tracker from 202 adult volunteers in the laboratory experiment in a well-controlled environment. Twenty features were extracted from the eye-tracking data and after the selection process the features were used in automated binary classification with a variety of machine learning classifiers including neural networks. The results of the classification using eye-tracking data features yielded 68% accuracy score, which can be considered satisfactory. Moreover, statistical analysis showed statistically significant differences in eye activity patterns between visualisations labelled as stressful or relaxing.
The CFD Analysis of the Combustion Chamber in Common Rail Engines
Authors: Tucki Karol , Bączyk Anna , Rek Bartłomiej , Wielewska Izabela
Published: January 2019

This paper reports on the development of the geometrical model of the combustion chamber. The results obtained from test were applied to numerical simulations – performed on the Farymann 18WM engine. The analysis was carried out in ANSYS Fluent environment using the finite volume element method. Based on the results, it can be stated that: (1) differences in test and simulation results result from: grid limitations, accuracy of the calculation models, simplifications and limitations of the models, (2) numerical simulations are helpful in determining the parameters of test objects without the need for employing a test set-up, finally, (3) unrestrained adjustment of simulation parameters enables modification of technical parameters of devices to assess their impact on the particular model.
Optimisation of electric arc model parameters based on simplex annealing and genetic algorithms
Authors: Chmielewski Tomasz , Kuczek Tomasz , Oramus Piotr
Published: January 2019

This paper presents the method for obtaining the coefficients of the dynamic Cassie-Mayr electric arc model by means of annealing and genetic optimisation algorithms. The extraction of the coefficients can be obtained by means of the iterative fitting process based on e.g. multiple measurements results. However, this requires a significant effort and can generate significant costs. The approach presented in this paper relies solely on simulations. The methodology used herein consists in finding the match to the maximum produced TRV generated during high-voltage shunt reactor current breaking, for ideal switch and conductance based Cassie-Mayr circuit breaker models. This is done for a given chopping current value assigned to the ideal switch which is used as a target. The arc model coefficients are obtained by means of the optimisation process for various values of the desired chopping current level to be reflected by the Cassie-Mayr conductance-based electric arc model. As a result, an advanced conductance based model can be used for assessment of switching overvoltage. Genetic and simplex annealing algorithms have been selected for optimisation. The models as well as the optimisation process were conducted in EMTP-ATP software using its built-in functionalities. The article presents the error assessment and sample traces.
Stochastic Elasto-Plastic Analysis of Necking Bar with Random Tvergaard Coefficients
Authors: Strąkowski Michai , Kamiñski Marcin
Published: January 2019

This paper reports on the computational modelling of static extension tests of the round steel bar. The main objective was to apply the generalised stochastic perturbation technique implemented as the Stochastic Finite Element Method to carry out the numerical simulation of its elasto-plastic behaviour. This approach was based on: the general order Taylor expansion of all input random variables and the resulting state functions of their average means, as well as on the Least Squares Method employed to determine analytical functions of in-between design parameters and the given structural responses. Tvergaard coefficients were assumed as the uncorrelated Gaussian random variables to check the effect of material porosity uncertainty on the statistical scattering of its deformations and stresses. The computational implementation employed the FEM system ABAQUS and computer algebra system MAPLE, including polynomial and non-polynomial local response functions of the displacements, plastic strains and reduced stresses. Moreover, 4-node axisymmetric, continuum, reduced-integration FEM elements (CAX4R) were used in the conducted analyses. The basic probabilistic characteristics of the structural response (expectations, coefficients of variation, skewness and kurtosis) were determined throughout the entire deformation process as the functions of input uncertainty level. The obtained results were finally contrasted with the classical Monte-Carlo Simulation scheme and the semi-analytical technique for input coefficient of variation of porous plasticity coefficients not larger than 0.20.
Experimental and numerical investigation on the components of a pantograph slider suspension
Authors: Zdziebko Paweł , Martowicz Adam , Uhl Tadeusz
Published: January 2019

Mechanical properties of the components of a pantograph’s slider suspension system have large influence on the quality of pantograph-catenary interaction. In the paper the authors present the results of their experimental research on the springs that are used in the pantograph being currently in operation in Europe. Static and dynamic tests were performed, which were aimed at determining the stiffness and damping coefficients respectively. Subsequently, the procedure for automated numerical model building for the pantograph’s springs was prepared employing the Python programming language and the MSC Marc solver. When a spring model is build (accordingly to the geometric properties of the springs used in tests), the elaborated algorithm iteratively tunes the material properties and computes static and dynamic load-cases, making direct reference to the experimental procedure. After completing several iterations the numerical model is finally validated, and proper material properties, as the Young modulus and the coefficients of Rayleigh damping model, are found. Then, the obtained model can be used to determine the damping and stiffness coefficients for springs characterizing various diameters, wire diameters, numbers of turns, etc. The presented modelling tool is useful for determining the pantograph sliders suspension characteristics.
Influence of elongation factor on distributions of effective strain and flow stress for pushing through a conical die process of round bars made from S355 steel
Authors: Miłek Tomasz
Published: January 2019

The paper presents computer modelling results of researches on pushing through a conical die process of round bars. Calculations were carried out using the commercial code QFORM-2D, based on the Finite Element Method (FEM). Investigations involved the use of circular sectioned S355 (1.0577) steel segments of rods with diameter of 9 mm and conical dies with different diameter of sizing portion of a die (d = 7.1 mm; 7.6 mm and 8.0 mm). The aim of the paper is to compare distributions of effective strain and flow stress in longitudinal sections of round bars at different elongation factors (λ1 = 1.24, λ2 = 1.37 and λ3 = 1.57).
Experimental verification of a numerical surface roughness model for metallic bodies under large plastic strain
Authors: Sidun Paweł
Published: January 2019

The present work describes selected aspects of numerical modelling of the process of bonding metal alloys with consideration for micro-roughness, as well as experimental verification. The plastic-elastic contact between two deformable bodies was investigated in a DEFROM FEM environment, and verified at the test stand. The present paper demonstrates selected results of contact modelling investigated using aluminium-copper samples, in relation to their elastic-plastic range. The real surface profile helped to create a mathematical model of surface roughness measured using a laser microscope. Dependency between a blade of a tool and a feed was used to build a numerical model of roughness based on the arithmetic average value of the roughness profile. The work presents also a process of simplification of real surface roughness for the needs of numerical calculations. The paper investigates an impact of wave roughness at obtained values on effective plastic strain and stress. Additionally, numerical analysis shows a need to enter a new roughness wave correction factor assuming a zero value of the coefficient of friction. This is due to the interaction of metallic surfaces within the plastic contact zone. The obtained results allow the estimation of the impact of surface force interaction expressed by the wave coefficient factor. The experimental verification of numerical calculations allowed the estimation of the actual impact of the micro-cutting process in the entire friction process. Further analysis of obtained results permits the author to explain the surface phenomena occurring during the friction process, such as adhesion or diffusion, and outline the development direction of numerical methods.
Computer simulation in identification and elimination of waste in the production process
Authors: Biniek Agata , Terelak-Tymczyna Agnieszka
Published: January 2019

This paper lays the theoretical foundations for the characterisation the course of processes in production engineering by means of computer tools, with the focus on the essence and benefits resulting from the use the programmes in question. The main objective of this study is to employ a selected computer tool for modelling, analysing and simulating a selected product manufacturing process to identify areas in the process that require improvement. The work involved the Tecnomatix Plant Simulation programme, in which the existing production process was modelled. The created model was used to simulate the runtime of the production lot, identify bottlenecks and analyse production losses, such as: waiting, stocks, and unnecessary transport. The conducted analysis has produced an outcome in the form of methods for eliminating identified production losses and modifying the model. The simulations were subsequently carried out on a modified model, which allowed determining the level of improvement of the assumed indicators, e.g. order completion time, set-up time, waiting time, stocks. The selected tool served not only as a means to visualising the course of the manufacturing process but also enabled us to optimise and improve it. The article presents the possibilities of using simulation programmes to identify and eliminate waste in production processes. In addition, the conclusions show not only the results of the simulations but also the most important benefits resulting from the use of this type of tools in production engineering, in particular in lean production management.
Hysteresis modeling and investigations of a piezoelectric ring bender using Bouc-Wen model
Authors: Regulski Roman
Published: January 2019

The paper describes theoretical and experimental investigation of applying Bouc-Wen model in displacement modeling of piezelectric ring benders. Under the increasing demand for more accurate position control systems, various hysteresis models appropriate for control purpose of mechanical systems have been proposed. Most of these models are based on phenomenological approach, for example: Prandtl–Ishlinskii or Krasnosel’skii-Pokrovskii and other, friction based like Maxwell-slip model. This paper presents a model described in analytical form, called the Bouc-Wen model, appropriate for position control purpose. Paper presents histeresis investigation results of Noliac CMBR05 ring bender under different voltages. Furthermore, article depicts how model was numerically implemented and investigated on dSpace Control System with Matlab Simulink Software for future research on real time position control with inverted hysteresis model.
Sensitivity analysis of a municipal wastewater treatment plant model
Authors: Król Paweł , Gallina Alberto , Lubieniecki Michał , Uhl Tadeusz , Żaba Tadeusz
Published: January 2019

Waste management is a crucial process to keep the environment in wholesome conditions. The environmental impact of solid waste and wastewater is reduced through construction of appropriate disposal installations. The objective of wastewater treatment in biological reactors is to control the process of biomaterial growth by aerating the sewage content. The process is complex, as depending on a plenty of parameters. In the last decades an effective numerical model, called the Activated Sludge Model (ASM), has been proposed for describing the biological process. The ASM is implemented in the Benchmark Simulation Model (BSM) that simulates the whole wastewater treatment process. The most important parameters in ASM are the kinetic and stoichiometric coefficients. The former describes rate-concentration dependence. The latter characterises the relationship between the components of chemical reactions taking place in the cleaning process. Above parameters are determined by on-site calibration and their importance is relevant during the development of numeric models. This paper aims to examine the influence of kinetic and stoichiometric parameters on the wastewater treatment process of a plant in Płaszów, Kraków. The analysis is carried out by a sample-based numerical procedure. It highlights the ASM parameters playing a major role in the treatment process. Results obtained from the analysis are important for future validation and optimisation processes.