displaying 1000 best results Help
Search results for: ALMOST PERIODIC POINT
-
Existence of periodic orbits for a perturbed vector field
PublicationPrzy nałożeniu pewnego warunku na odwzorowanie Poincarego, wyrażonego w języku indeksów iteracji, dowodzi się istnienia orbit periodycznych dla zaburzonego pola wektorowego.
-
Periodic Points for Sphere Maps Preserving MonopoleFoliations
PublicationLet S^2 be a two-dimensional sphere. We consider two types of its foliations with one singularity and maps f:S^2→S^2 preserving these foliations, more and less regular. We prove that in both cases f has at least |deg(f)| fixed points, where deg(f) is a topological degree of f. In particular, the lower growth rate of the number of fixed points of the iterations of f is at least log|deg(f)|. This confirms the Shub’s conjecture in...
-
Comparison of 3D Point Cloud Completion Networks for High Altitude Lidar Scans of Buildings
PublicationHigh altitude lidar scans allow for rapid acquisition of big spatial data representing entire city blocks. Unfortunately, the raw point clouds acquired by this method are largely incomplete due to object occlusions and restrictions in scanning angles and sensor resolution, which can negatively affect the obtained results. In recent years, many new solutions for 3D point cloud completion have been created and tested on various objects;...
-
Processing of point cloud data retrieved from terrestrial laser scanning for structural modeling by Finite Element Method
PublicationFinite Element Method is one most popular contemporary method of strength analysis. The method is an advanced method for solving differential equations, based on discretization, which means that area is divided into finite elements. Each finite element has a solution of the equation approximated by specific functions and performing the actual calculations only for nodes of this division. Finite Element Method is widely used in...
-
Numerical solution of fractional neutron point kinetics in nuclear reactor
PublicationThis paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme...
-
Adapting the pinch point analysis to improve the ORC design process
PublicationPinch point analysis can be adapted so as to assist in the early stages of designing the ORC systems. Typically used in determining the working parameters of heat exchangers, it can be employed to improve the heat fitting between the source of heat and the working fluids of the ORC system. To attain the parametric match, an algorithm was built enabling quick estimation of the possible heat reception by the specific working fluid....
-
Laboratoryjny przetwornik a/c typu "floating-point" na bazie karty DAQ
PublicationW artykule przedstawiono zrealizowany przetwornik a/c typu "floating-point" na bazie karty akwizycji danych typu PCI-6221 uzupełnionej o wzmacniacz wejściowy o programowanym wzmocnieniu. Opisywany przetwornik jest podstawą ćwiczenia w laboratorium studenckim. W skład ćwiczenia wchodzą dodatkowo program symulacyjny pozwalający zapoznać się z ideą pracy przetworników typu "floating-point", a następnie przejść do realizacji przetwornika...
-
4-Point beam tensile test on a soft adhesive
PublicationAn adhesive butt joint with a soft bondline has been studied. A series of experiments was conducted on test pieces constituted of aluminium adherends bonded with a low modulus epoxy adhesive, ScotchWeld™ 2216. The joint was subjected to four point bending, in tension/compression loading, under constant deflection rate, with the bondline being parallel to the applied load. The objective was to examine and evaluate crack nucleation...
-
Simulation of the weight averaging of pulse frequency modulated sensor output signal
Open Research DataThe aim of the research is investigation of the efficiency of weight averaging of pulse frequency modulated signal. It was shown that from the point of view of the reduction of the sampling error the best are polynomial weighing functions, for which the maximum of this component error decreases proportionally to the appropriate power of the number of...
-
Size-exclusion chromatography for the determination of the boiling point distribution of high-boiling petroleum fractions
PublicationThe paper describes a new procedure for the determination of boiling point distribution of high-boiling petroleum fractions using size exclusion chromatography with refractive index detector. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with the flame ionization detection. This study revealed that in spite of substantial differences...
-
Model of heat transfer in the stagnation point of rapidly evaporating microjet
PublicationThe paper presents investigation into the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. Experiments were conducted using the nozzle size of 70 and 100 mikrometer respectively. In the course of investigations obtained were experimental relations between heat flux and wall superheating. It was proved that the phenomenon is similar to that of pool boiling...
-
Multilevel inverter neutral-point voltage sensor diagnostic based on the Extended Kalman Filter
PublicationA new algorithm for neutral point voltage imbalance estimation in DC link of the three-level (3L) neutral point clamped (NPC) voltage source inverter (VSI) is proposed. Application of the proposed algorithm does not require any additional sensors. The unbalanced voltage calculation is based on the information derived from the inverter output measured currents and from the knowledge of the load model parameters. In order to estimate...
-
Postquarter-Point Case of Ship’s Side-Berthing and Its Influence on Marine Fender Pitch
PublicationThis paper presents a critical analysis of some selected codes and practical recommendations used as basic rules in the design procedures of modern marine fender systems. The first part of the discussion pertains to the existing equations used in calculating the eccentricity coefficient in the ship’s kinetic energy equation and the maximum allowable fender pitch (spacing) in a set of fenders installed along a quay wall. A new approach...
-
From a Point Cloud to a 3D Model - an Exercise for Users of AutoCAD and Revit
PublicationThe paper presents a proposal of the topic of an exercise for students of building faculties as part of classes on 3D modelling. The task consists in creating a three-dimensional model based on the measurement obtained with the Leica P30 laser scanner. Due to the maximum number of points in the cloud in the presented programs, the output files must be properly cleared and reduced. The point cloud was pre-processed in Cyclone software....
-
Methods for quality improvement of multibeam and LiDAR point cloud data in the context of 3D surface reconstruction
PublicationPoint cloud dataset is the transitional data model used in several marine and land remote-sensing applications. During further steps of processing, the transformation of point cloud spatial data to more complex models containing higher order geometric structures like edges and facets may be possible, if an appropriate quality level of input data is provided. Point cloud datasets usually contain a considerable amount of undesirable...
-
Protection of Earthing Reactor Connected to the Star Point of a High Voltage Shunt Reactor
PublicationThe article presents the problem of protection of earthing reactors connected to the star point of shunt reactors in high voltage lines, with particular regard to the detection of internal faults. Model analyses for an actual system commissioned in 2015, which is intended to be provided with earthing reactors, are included.
-
Fixed Point Theory and Applications
Journals -
Processing of LiDAR and Multibeam Sonar Point Cloud Data for 3D Surface and Object Shape Reconstruction
PublicationUnorganised point cloud dataset, as a transitional data model in several applications, usually contains a considerable amount of undesirable irregularities, such as strong variability of local point density, missing data, overlapping points and noise caused by scattering characteristics of the environment. For these reasons, further processing of such data, e.g. for construction of higher order geometric models of the topography...
-
3D point cloud as a representation of silo / tank
Open Research DataThe product presents a point cloud in the set of coordinates X Y Z. The data was obtained by terrestrial laser scanning and its processing for the analysis of tanks geometry. The development process indicates the possibility to obtain the reliable results useful for the evaluation of the tank side surfaces geometry.
-
Lasing modes of infinite periodic chain of quantum wires
Publication -
Computer assisted method for proving existence of periodic orbits
Publication -
The Conley Index and Rigorous Numerics for Attracting Periodic Orbits
Publication -
Periodic boundary value problems for functional differential equations
PublicationPrzedmiotem badań były równania różniczkowo-funkcyjne dość ogólnej postaci z warunkami brzegowymi typu okresowego. Podano warunki dostateczne na istnienie jedynego rozwiązania (zerowego) odpowiedniego zagadnienia liniowego z okresowymi warunkami brzegowymi. Te wyniki zostały wykorzystane aby pokazać, że odpowiednio skonstruowane ciągi monotoniczne są jednostajnie zbieżne do jedynego, w pewnym segmencie, rozwiązania zagadnienia...
-
Waveform relaxation methods for periodic differential-functional systems.
PublicationPrzedmiotem badań były układy różniczkowo-funkcyjne z warunkiem okresowym.Prawą stronę układu z argumentem funkcyjnym przedstawiono w nowej formie wygodnej do stosowania metody relaksacyjnej ''waveform''. Podano warunki dostateczne (dyskutowano dwa typy takich warunków) przy których wyjściowy problem ma rozwiązanie i odpowiednie ciągi relaksacyjne są do niego zbieżne. Dyskutowano w szczegółach przedstawiony problem numeryczny...
-
Periodic and continuous niching in genetic optimization of detection observers.
PublicationNiszowanie stanowi mechanizm, którego celem jest utrzymanie gorzej przystosowanych osobników tak, aby populacja była różnorodna (zawierała także osobniki przeciętne i słabiej przystosowane). Niszowanie prowadzi do utrzymania odpowiedniej liczby istniejących gatunków, zarówno tych bardziej licznych (lepiej przystosowanych), jak i tych mniej licznych (słabiej przystosowanych), a przez to zapobiega przedwczesnej zbieżności algorytmów....
-
Periodic points of latitudinal maps of the $m$-dimensional sphere
PublicationLet f be a smooth self-map of the m-dimensional sphere Sm. Under the assumption that f preserves latitudinal foliations with the fibres S1, we estimate from below the number of fixed points of the iterates of f. The paper generalizes the results obtained by Pugh and Shub and by Misiurewicz.
-
Fractional neutron point kinetics equations for nuclear reactor dynamics – Numerical solution investigations
PublicationThis paper presents results concerning numerical solutions to a fractional neutron point kinetics model for a nuclear reactor. The paper discusses and expands on results presented in (Espinosa-Paredes et al., 2011). The fractional neutron point kinetics model with six groups of delayed neutron precursors was developed and a numerical solution using the Edwards’ method was proposed (Edwards et al., 2002). The mathematical model...
-
Assessing historical church tower asymmetry using point cloud spatial expansion
PublicationChurch towers are key cultural heritage. In theory, towers are vertical, while facade elements are symmetrically positioned around the tower axis. However, during service of a structure, building and lifetime conditions cause deviations, with associated risks. Laser scanning point clouds can be used to assess the structural state but a universal approach was missing. The proposed algorithm first estimates the tower inclination,...
-
Photovoltaic Maximum Power Point Technique based on Incremental Conductance (INCON) control algorithm
PublicationMaximum output power status can significantly improve the deployment rate of solar energy system. In order to get the maximum power output, issue of tracking maximum power point (MPP), reduced harmonics around MPP and improve efficiency of the solar power energy system, this paper presents the improved maximum power point tracking (MPPT) control...
-
A Cost-Effective Method for Reconstructing City-Building 3D Models from Sparse Lidar Point Clouds
PublicationThe recent popularization of airborne lidar scanners has provided a steady source of point cloud datasets containing the altitudes of bare earth surface and vegetation features as well as man-made structures. In contrast to terrestrial lidar, which produces dense point clouds of small areas, airborne laser sensors usually deliver sparse datasets that cover large municipalities. The latter are very useful in constructing digital...
-
Evaluation of the Combination of Muscle Energy Technique and Trigger Point Therapy in Asymptomatic Individuals with a Latent Trigger Point
Publication -
Reliability Analysis of Sea Cliff Slope Stability by Point Estimate Method
PublicationThe paper presents a reliability analysis of a sea cliff slope. The cliff, located in Jastrzębia Góra, is characterised by a complicated geological structure. Although currently stable, it is in fact close to the limit state. The objective of this paper is to present the point estimate method (PEM) of determining the mean value and standard deviation of the safety factor of the slope. Assuming its normal distribution, these statistical...
-
Reliability Analysis of Sea Cliff Slope Stability by Point Estimate Method
PublicationThe paper presents a reliability analysis of a sea cliff slope. The cliff, located in Jastrzębia Góra, is characterised by a complicated geological structure. Although currently stable, it is in fact close to the limit state. The objective of this paper is to present the point estimate method (PEM) of determining the mean value and standard deviation of the safety factor of the slope. Assuming its normal distribution, these statistical...
-
Classification of objects in the LIDAR point clouds using Deep Neural Networks based on the PointNet model
PublicationThis work attempts to meet the challenges associated with the classification of LIDAR point clouds by means of deep learning. In addition to achieving high accuracy, the designed system should allow the classification of point clouds covering an area of several dozen square kilometers within a reasonable time interval. Therefore, it must be characterized by fast processing and efficient use of memory. Thus, the most popular approaches...
-
Numerical solution analysis of fractional point kinetics and heat exchange in nuclear reactor
PublicationThe paper presents the neutron point kinetics and heat exchange models for the nuclear reactor. The models consist of a nonlinear system of fractional ordinary differential and algebraic equations. Two numerical algorithms are used to solve them. The first algorithm is application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. The second involves building an analog scheme in the FOMCON Toolbox...
-
Deformation Analysis of a Composite Bridge during Proof Loading Using Point Cloud Processing
PublicationRemote sensing in structural diagnostics has recently been gaining attention. These techniques allow the creation of three-dimensional projections of the measured objects, and are relatively easy to use. One of the most popular branches of remote sensing is terrestrial laser scanning. Laser scanners are fast and efficient, gathering up to one million points per second. However, the weakness of terrestrial laser scanning is the...
-
Nonlinear planar modeling of massive taut strings travelled by a force-driven point-mass
PublicationThe planar response of horizontal massive taut strings, travelled by a heavy point-mass, either driven by an assigned force, or moving with an assigned law, is studied. A kinematically exact model is derived for the free boundary problem via a variational approach, accounting for the singularity in the slope of the deflected string. Reactive forces exchanged between the point-mass and the string are taken into account via Lagrange...
-
Optimization algorithm and filtration using the adaptive TIN model at the stage of initial processing of the ALS point cloud
PublicationAirborne laser scanning (ALS) provides survey results in the form of a point cloud. The ALS point cloud is a source of data used primarily for constructing a digital terrain model (DTM). To generate a DTM, the set of ALS observations must be first subjected to the point cloud processing methodology. A standard methodology is composed of the following stages: acquisition of the ALS data, initial processing (including filtration),...
-
Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublicationA thermodynamic relation between perturbations of pressure and mass density in the magnetohydrodynamic flow is theoretically studied. Planar magnetohydrodynamic perturbations with the wave vector, which forms a constant angle with the equilibrium magnetic field, are under study. The theory considers thermal conduction of a plasma and the deviation from adiabaticity of a flow due to some kind of heating–cooling function. It also...
-
Doubly miniaturized rat-race coupler with periodic pbg structures
PublicationW referacie zaprezentowano projekt oraz wyniki eksperymentu podwójnie zminiaturyzowanego sprzęgacza pierścieniowego. Wstępny stopień miniaturyzacji uzyskano poprzez modyfikację impedancji charakterystycznych oraz długości elektrycznych odpowiednich sekcji linii mikropaskowych, natomiast dodatkową redukcję powierzchni osiągnięto poprzez implementację kaskad komórek PBG w odcinkach linii mikropaskowych. Wyniki eksperymentu potwierdzają...
-
Computer Assisted Proof of the Existence of a Periodic Orbit in the Rössler Equations
Publication -
Indices of interations and periodic points of simplical maps of smooth type
PublicationW pracy dowodzi się symplicjalnego odpowiednika twierdzenia Chowa, Mallet-Paret i Yorke´a. Otrzymany wynik służy do badania punktów periodycznych odwzorowań symplicjalnych gładkiego typu.
-
Electromagnetic curtain effect and tunneling properties of multilayered periodic structures
PublicationArtykuł przedstawia analizę rozpraszania fali elektromagnetycznej na wielowarstwowych strukturach periodycznych. W analizowanych strukturach zaobserwowano efekt tunelowania fali oraz efekt przestrajania pasm zaporowych/przepustowych (efekt kurtyny elektromagnetycznej)
-
Acoustic Streaming Induced by Periodic and Aperiodic Sound in a Bubbly Liquid
PublicationThe vortex ow which follows intense sound propagating in a bubbly liquid, is considered. The reasons for acoustic streaming are both nonlinearity and dispersion. That makes streaming especial as compared with that in a Newtonian uid. Conclusions concern the vortex ow induced in a half-space by initially harmonic or impulse Gaussian beam. The vortex ow recalls a turbulent ow with increasing in time number of small-scale vortices...
-
Acoustic radiation force and streaming caused by non periodic acousticsource.
PublicationTeoria i obliczenia numeryczne przepływu rotacyjnego (''streamingu'') towarzyszącemu fali akustycznej w przepływach lepkich nieliniowych. Fala wywołująca może być nieokresowa: impulsowa lub paczka falowa itd. Przykład pojedynczego pulsu rozpatrywany. Ilustracje delikatnej struktury czasowej powstania fal rotacyjnych przedstawione na rysunkach.
-
Periodic and impulsive lubrication of hip joint with stochastic rough surface.
PublicationNiniejsza praca przedstawia porównanie wartości nośności uzyskanych numerycznie dla niestacjonarnego smarowania impulsywnego oraz niestacjonarnego smarowania periodycznego sferycznego stawu biodrowego człowieka. W obu przypadkach przyjęto, że smarująca ciecz synowialna ma własności lepkosprężyste a występy chropowatych powierzchni chrząstki stawowej zmieniają się losowo. Charakterystyki zmiennych w czasie rozkładów wartości ciśnienia...
-
On the Nielsen fixed point theory for multivalued mappings
Publication -
Fixed point indices of iterated planar maps
PublicationW artykule dokonuje się przeglądu wyników dotyczących indeksów punktu stałego iteracji odwzorowań planarnych, sformułowane zostają otwarte pytania i podane nowe dowody w przypadku gładkim.
-
The point forecast of the situation of the examined company on the market
PublicationOkreślono sytuację badanego przedsiębiorstwa na rynku za pomocą analizy portfolio, w aspektach wzrostu rynku oraz względnego udziału badanego przedsiębiorstwa w rynku. Analiza objęła zarówno okres retrospektywny jak i prognozowany.
-
Fixed point indices of iterations of planar homeomorphisms.
PublicationW pracy bada się postać indeksów iteracji lokalnych homeomorfizmów płaszczyzny.
-
On the regularity of the displacement sequence of an orientation preserving circle homeomorphism
PublicationWe investigate the regularity properties of the displacemnet sequence of an orientation preserving circle homeomorphism. is rational, then ηn(z) is asymptotically periodic with semi-period q. This
-
Airborne Laser Scanning Point Cloud Update by Used of the Terrestrial Laser Scanning and the Low-Level Aerial Photogrammetry
PublicationLaser scanning technology is a spatial information gathering technique which is commonly used all over the world. Systems where the red-light beam are used, are divided into: terrestrial, mobile and airborne scanning systems. The main differences between those are the accuracy, the data acquisition solution (f. e. in ALS and MLS besides of the laser scanner, the inertial navigation system is required) and the covered area in one...
-
ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublicationThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
-
ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublicationThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
-
Minimal number of periodic points for smooth self-maps of RP^3
PublicationNiech f będzie gładkim odwzorowaniem 3-wymiarowej rzeczywistej przestrzeni rzutowej w siebie, r będzie ustaloną liczbą naturalną. W artykule wyznaczona została minimalna liczba punktów r-periodycznych w gładkiej klasie homotopii odwzorowania f.
-
Minimal number of periodic points for smooth self-maps of S^3
PublicationW pracy wyznaczona została najmniejsza liczba punktów periodycznych w gładkiej klasie homotopii odwzorowania sfery trójwymiarowej w siebie.
-
Characteristic equations for the lasing modes of infinite periodic chain of quantum wires
Publication -
Low-threshold lasing eigenmodes of an infinite periodic chain of quantum wires
Publication -
Plasmon and structure resonances in the scattering of light by a periodic chain of silver nanocylinders
Publication -
Natural modes of an active slab microcavity with air-filled periodic inclusions
Publication -
Vector Field Editing and Periodic Orbit Extraction Using Morse Decomposition
Publication -
Maps with bounded sequence of indices of interations and finitaly many periodic points
PublicationW pracy badane są związki pomiędzy globalną topologiczną strukturą przestrzeni wyrażoną w terminach charakterystyki Eulera-Poincar odwzorowań na niej określonych, a spełniających założenia z tytułu, a lokalnymi własnościami przestrzeni zdeterminowanymi przez zachowanie się tych odwzorowań w punkatach periodycznych.
-
An integrated periodic structure in Silicon technology to improve power amplifier parameters
PublicationNowa zintegrowana struktura periodyczna wykonana w technologii krzemowej została wprowadzona do międzystopniowego układu dopasowania wzmacniacza mocy. Dzięki temu stwiedzono poprawę większości charakterystyk wzmacniacza, jak również własności filtrujących (tłumienie harmonicznych).
-
On the growth of the number of periodic points for smooth self maps of a compact manifold
PublicationDla ciągłego przekształcenia jednospójnej rozmaitości wymiaru co najmniej 3 w siebie, wykazujemy, że wzrost liczby punktów r-periodycznych w klasie homotopii może być nie szybszy niż liniowy, dla dowolnego, ustalonego r.
-
Numerical contribution to the viscoelastic magnetic lubrication of human joint in periodic motion.
PublicationPraca przedstawia rozwiązania problemu smarowania stawów człowieka w układzie współrzędnych ortogonalnych krzywoliniowych dla ruchu nieustalonego okresowego w polu magnetycznym. Uwzględnia się lepkosprężyste właściwości cieczy synowialnej w trakcie smarowania
-
Modification of the operating point of residual current transformers for high frequency earth fault currents detection
PublicationFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when earth fault current with high frequency components occurs. Serious hazard of electrocution exists then. One of the most important element of residual current devices is a residual current transformer with iron core. Tripping characteristic of residual current devices strictly...
-
Simplified probabilistic analysis of settlement of cyclically loaded soil stratum using point estimate method
PublicationThe paper deals with the probabilistic analysis of settlement of a non-cohesive soil layer subjected to cyclic loading. Originally, the settlement assessment is based on deterministic compaction model which requires integration of a set of differential equations. However, making use of the Bessel functions the settlement of the soil stratum can be calculated by means of simplified algorithm. The compaction model parameters were...
-
Point cloud based surface analysis of prestressed concrete element in exceeded state of serviceability
PublicationBy definition, serviceability state is characterized by the fact that despite meeting the requirements associated with carrying capacity, the object is not suitable for use. Serviceability limit state refers to factors, such as durability, overall stability, fire resistance, cracking, excessive vibration. Perfect examples of exceeded serviceability state are the improper vibration of a skyscraper, which inhabitants may suffer from...
-
Controlling nodal displacement of pantographic structures using matrix condensation and interior-point optimization: A numerical and experimental study
PublicationThis study presents an innovative approach for the precise control of nodal displacements in pantographic structures. The method is founded on the Matrix Condensation of Force Method, seamlessly integrated with an Interior Point Optimization algorithm. This combination offers a unique advantage by allowing users to manipulate displaced nodes within a defined coordination domain. Furthermore, this approach introduces the Interior...
-
Time-Domain Description of Point-Source Acoustic Wavefields as a Useful Approach in Ultrasonic Techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
-
Time-domain description of point-source acoustic wavefields as a useful approach in ultrasonic techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
-
Influence of aggregates angularity on the locking point of asphalt mixtures
Publication -
Local fixed point indices of iterations of planar maps
PublicationW artykule podana zostaje postać indeksów iteracji dla pewnej klasy odwzorowań planarnych. Podstawowymi narzędziami stosowanym w pracy są liczba Nielsena i indeks Conleya.
-
Fixed point index for $G$-equivariant multivalued maps
Publication -
Periodicity of a sequence of local fixed point indices of iterations
PublicationPraca uogólnia klasyczne twierdzenie Shuba i Sullivana o periodyczności ciągu indeksów punktu stałego iteracji odwzorowań gładkich na szerszą klasę przekształeń.
-
Sequences of fixed point indices of iterations in dimension 2.
PublicationW pracy dowodzi się, że każdy ciąg liczb całkowitych spełniający relacje Dolda może zostać zrealizowany jako ciąg indeksów punktu stałego iteracji ciągłego odwzorowania dwuwymiarowego dysku w siebie.
-
Photovoltaic maximum power point varying with illumination and temperature
PublicationW pracy przedstawiono wyniki badań eksperymentalnych zmian położenia punktu maksymalnej mocy na charakterystyce prądowo-napięciowej modułu ogniw fotowoltaicznych, związanych ze zmieniającą się temperaturą i natężeniem padającego promieniowania. Badano czas narastania napięcia pracy i temperatury ogniw w początkowej fazie ekspozycji na promieniowanie słoneczne. Przedstawiono niektóre praktyczne aspekty zastosowania układu automatycznego...
-
Three-point bending test of sandwich beams supporting the GFRP footbridge design process - validation
PublicationSome selected aspects concerning material and construction design issues for pedestrian footbridge made of GFRP composite materials are elaborated in this paper. The analysis is focused on validation tests, which are particularly important because of the advanced technology and materials that are used for this innovative bridge. The considered footbridge is a sandwich-type shell structure comprising of PET foam core and outer skins...
-
Improving the Accuracy of Automatic Reconstruction of 3D Complex Buildings Models from Airborne Lidar Point Clouds
PublicationDue to high requirements of variety of 3D spatial data applications with respect to data amount and quality, automatized, effcient and reliable data acquisition and preprocessing methods are needed. The use of photogrammetry techniques—as well as the light detection and ranging (LiDAR) automatic scanners—are among attractive solutions. However, measurement data are in the form of unorganized point clouds, usually requiring transformation...
-
Solving Boundary Value Problems for Second Order Singularly Perturbed Delay Differential Equations by ε-Approximate Fixed-Point Method
PublicationIn this paper, the boundary value problem for second order singularly perturbed delay differential equation is reduced to a fixed-point problem v = Av with a properly chosen (generally nonlinear) operator A. The unknown fixed-point v is approximated by cubic spline vh defined by its values vi = vh(ti) at grid points ti, i = 0, 1, ... ,N. The necessary for construction the cubic spline and missing the first derivatives at the boundary...
-
Single-phase, Five-level Inverter with SPWM-Based Neutral Point Voltage Balancing Scheme
PublicationMultilevel inverter topologies provide several advantages over two-level inverter configuration. These benefits are the reason for the growing interest in multilevel topologies among research society. One of the most popular topological concepts (diode and active switch clamping) requires neutral-point potential balancing due to series-connected capacitor banks across the input dc link in such derived inverter configurations. This...
-
Local and global response of sandwich beams made of GFRP facings and PET foam core in three point bending test
PublicationIn the paper behaviour of laminated sandwich beams (FRP face sheet – PET foam core – FRP face sheet) subjected to three point bending is studied. The paper aim is to find practical descriptions enabling effective and accurate estimation of the elastic response, damage and failure of the beams, basing on experiments and static calculations. Therefore a number of tests are described, that were done on laminated coupons and foam specimens...
-
Minimizing the number of periodic points for smooth maps. Non-simply connected case
PublicationNiech f będzie gładkim odwzorowaniem zamkniętej rozmaitości o wymiarze wiekszym niż 2, a r ustaloną liczbą naturalną. W artykule zdefiniowany został niezmiennik topologiczny równy minimalnej liczbie punktów r-periodycznych w gładkiej klasie homotopii f.
-
Heating caused by a non periodic ultrasound. Theory and calculations on pulse and stationary sources.
PublicationPrzedstawiono teorię ewolucji ogrzewania na skutek przejścia fali akustycznej każdego typu. Przedyskutowano obliczenia na podstawie nowych wzorów dla fali impulsowej i uderzeniowej. Wzory zgadzają się z klasycznymi w wypadku fal okresowych.
-
Hybrid technique for the analysis of scattering from periodic structures composed of irregular objects
PublicationW pracy zaproponowano nową metodę hybrydową do badania zjawiska rozpraszania fali elektromagnetycznej na strukturach periodycznych złożonych z obiektów rozpraszających o nieregularnym kształcie. Zaprezentowana metoda została wykorzystana do badania własności nowych struktur falowych. Uzyskane wyniki numeryczne zostały zweryfikowane eksperymentalnie.
-
Comparisson between impulsive and periodic non-newtonian lubrication of human hip joint
PublicationOpis smarowania powierzchni sferycznych stawu biodrowego człowieka przedstawiono w aspektach hydromechaniki, przy pomocy równań zachowania pędu i ciągłości strugi dla osiowo niesymetrycznego przepływu cieczy lepkosprężystej z wykorzystaniem związków konstytutywnych Rivlina Ericksena we współrzędnych sferycznych.
-
Periodic stick-slip deformation of granular material under quasi-static conditions
PublicationArtykuł omawia wyniki porównawcze między doświadczeniami z użyciem metody korelacji obrazów cyfrowych (DIC) a symulacjami z użyciem metody elementów dyskretnych (DEM) dla problemu przesuwającej się sztywnej ścianki w piasku. W doświadczeniach zaobserwowano w piasku deformację typu slip-stick, która nie została odtworzona w obliczeniach DEM..
-
A New Adaptive Method for the Extraction of Steel Design Structures from an Integrated Point Cloud
PublicationThe continuous and intensive development of measurement technologies for reality modelling with appropriate data processing algorithms is currently being observed. The most popular methods include remote sensing techniques based on reflected-light digital cameras, and on active methods in which the device emits a beam. This research paper presents the process of data integration from terrestrial laser scanning (TLS) and image data...
-
A New Adaptive Method for the Extraction of Steel Design Structures from an Integrated Point Cloud
Open Research DataA new automatic and adaptive algorithm for edge extraction from a random point cloud was developed and presented herein. The proposed algorithm was tested using real measurement data. The developed algorithm is able to realistically reduce the amount of redundant data and correctly extract stable edges representing the geometric structures of a studied...
-
A pilot study to assess manufacturing processes using selected point measures of vibroacoustic signals generated on a multitasking machine
PublicationThe article presents the method for the evaluation of selected manufacturing processes using the analysis of vibration and sound signals. This method is based on the use of sensors installed outside the machining zone, allowing to be used quickly and reliably in real production conditions. The article contains a developed measurement methodology based on the specific location of microphones and vibration transducers mounted on...
-
A Reference Point Approach to Bi-Objective Dynamic Portfolio Optimization
Publication -
Four-point boundary-value problems for differential-algebraic systems
PublicationBadane są czteropunktowe problemy brzegowe dla układów równań różniczkowo-algebraicznych. Stosując metodę iteracji monotonicznych, podano warunki dostateczne na istnienie rozwiązań (jednego lub ekstremalnych) takich problemów. Podano przykład ilustrujacy otrzymane wyniki teoretyczne.
-
Proposition of aerial laser survey point cloud methodology modification
PublicationW rozdziale monografii autorzy sugerują nowe rozwiązanie - modyfikację metodologii analizy chmury punktów pozyskanej ze skaningu lotniczego w technologii LIDAR. Modyfikacja polega na poprzedzeniu procesu filtracji realizowanego w ETAPIE PRZETWARZANIA WSTĘPNEGO, algorytmem optymalizacji [Błaszczak 2006, Błaszczak, Kamiński 2007]. Głównym celem badań była kontrola wiarygodności i efektywności metodologii opracowania chmury punktów...
-
Model of heat transfer in the stagnation point of rapidly evaporating microjet
PublicationThe paper presents investigation in the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. It was proved that the phenomenon is similar to that of pool boiling. Results of experiments were compared with predictions by the model showing a good consistency.
-
Construction of Public Roads at the Meeting Point of Different Legislation Systems
Publication -
A Point Set Connection Problem for Autonomous Mobile Robots in a Grid
PublicationConsider an orthogonal grid of streets and avenues in a Manhattan-like city populated by stationary sensor modules at some intersections and mobile robots that can serve as relays of information that the modules exchange, where both module-module and module-robot communication is limited to a straight line of sight within the grid. The robots are oblivious and move asynchronously. We present a distributed algorithm that, given...
-
Three-Level Z-Source Neutral-Point-Clamped Inverter
PublicationThe paper describes construction and the principles of activity, attributes and potential of 3-phase Z-type inverters. The paper focuses on the basic system and suggested 3-level system of a NPC type Z-inverter, which was elaborated by authors. Simplified theoretical analysis of both systems has been verified by detailed simulation research. In the last section of the article, the possibility to build multilevel Z- inverters based...
-
Use of Bi-Temporal ALS Point Clouds for Tree Removal Detection on Private Property in Racibórz, Poland
PublicationTrees growing on private property have become an essential part of urban green policies. In many places, restrictions are imposed on tree removal on private property. However, monitoring compliance of these regulations appears difficult due to a lack of reference data and public administration capacity. We assessed the impact of the temporary suspension of mandatory permits on tree removal, which was in force in 2017 in Poland,...
-
Impact of cross-section centers estimation on the accuracy of the Point cloud spatial expansion using robust M-estimation and Monte Carlo simulation
PublicationThe point cloud spatial expansion (PCSE) method creates an alternative form of representing the shape of symmetrical objects and introduces additional descriptive geometric parameters. An important element of the procedure is determining the course of the axis of symmetry of cylindrical objects based on cross-sections of point clouds. Outliers occurring in laser measurements are of great importance in this case. In this study,...
-
Influence of Wood Moisture on Strength and Elastic Modulus for Pine and Fir Wood Subjected to 4-point Bending Tests
PublicationThe main purpose of this research paper was to determine the influence of the wood moisture on the strength and elastic modulus of pine and fir wood specimens subjected to the 4-point bending tests. Six bending tests for each wood species and for two different moisture level have been performed. Then, the advanced statistical analysis of the results has been carried out. On the basis of the obtained results, it has been noted that...