Search
displaying 1000 best results Help
Search results for: FIXED POINT THEOREM
-
Acoustic emission signals in concrete beams under 3-point bending (plain concrete, steel fibre reinforced concrete, steel bar reinforced concrete)
Open Research DataThe DataSet contains the results of the mechanical behaviour of concrete beams with dimensions 40 x 40 x 160 cm3under the 3-point bending. Two concrete mixes, both based on the same design, were produced in the test programme. Mixture #1 was the plain concrete (PC), consisting of cement CEM I 42.5R (380 kg/m3), water (165 kg/m3), aggregate 0/2 mm (648...
-
Bifurcation of equilibrium forms of an elastic rod on a two-parameter Winkler foundation
PublicationWe consider two-parameter bifurcation of equilibrium states of an elastic rod on a deformable foundation. Our main theorem shows that bifurcation occurs if and only if the linearization of our problem has nontrivial solutions. In fact our proof, based on the concept of the Brouwer degree, gives more, namely that from each bifurcation point there branches off a continuum of solutions.
-
GNSS INVENTORY OF HISTORIC NARROW-GAUGE RAILWAY LINE IN KOSZALIN UNDER EXTREMELY UNFAVORABLE MEASUREMENTS CONDITIONS FROM THE POINT OF VIEW OF SATELLITE SIGNALS AVAILABILITY
PublicationA team of academic researchers from the Gdańsk University of Technology, Gdynia Maritime University and the Polish Naval Academy have been working since 2009 on the methodology of using active GNSS geodetic networks for geodetic inventory of railways and on adapting this measurement technique for designing geometric layouts of railway and tram lines. Over the years, the team tested a variety of configurations of receivers and settings...
-
Technical aspects of nasal cavity surgery through the Le Fort I down-fracture approach: An otolaryngologist’s point of view based on 90 patients’ experience
Publication -
Multiple Solutions to Third-Order Differential Equations with Derivative Dependence and Deviating Arguments
PublicationIn this paper, we give some new results for multiplicity of positive (nonnegative) solutions for third-order differential equations with derivative dependence, deviating arguments and Stieltjes integral boundary conditions. We discuss our problem with advanced argument α and arbitrary β ∈ C([0,1],[0,1]), see problem (2). It means that argument β can change the character on [0,1], so β can be delayed in some set J ⊂ [0,1] and advanced...
-
Evaluation of the suitability of low hazard surfactants for the separation of phenols and carotenoids from red-flesh orange juice and olive mill wastewater using cloud point extraction
Publication -
Mutual Interaction between Temperature and DO Set Point on AOB and NOB Activity during Shortcut Nitrification in a Sequencing Batch Reactor in Terms of Energy Consumption Optimization
PublicationRecently, many wastewater treatment plants (WWTPs) have had to deal with serious problems related to the restrictive requirements regarding the euent quality, as well as significant energy consumption associated with it. In this situation, mainstream deammonification and/or shortened nitrification-denitrification via nitrite (so-called “nitrite shunt”) is a new promising strategy. This study shows the mechanisms and operating conditions...
-
FPGA-Based System for Electromagnetic Interference Evaluation in Random Modulated DC/DC Converters
PublicationField-Programmable Gate Array (FPGA) provides the possibility to design new “electromagnetic compatibility (EMC) friendly” control techniques for power electronic converters. Such control techniques use pseudo-random modulators (RanM) to control the converter switches. However, some issues connected with the FPGA-based design of RanM, such as matching the range of fixed-point numbers, might be challenging. The modern programming...
-
Positive solutions for second order impulsive differential equations involving Stieltjes integral conditions
PublicationIn this paper we investigate integral boundary value problems for fourth order differentialequations with deviating arguments.Wediscuss our problem both for advanced or delayedarguments. We establish sufficient conditions under which such problems have positivesolutions. To obtain the existence of multiple (at least three) positive solutions, we use afixed point theorem due to Avery and Peterson. An example is also included to...
-
Effect of Thermal Treatment of Birch Wood by Saturated Water Vapor on Granulometric Composition of Chips from Sawing and Milling Processes from the Point of View of Its Processing to Composites
PublicationThe goal of this work is to investigate the impact of thermal modification of birch wood with saturated steam on the particle size distribution of the sawing and milling process. Birch wood (Betula pendula Roth) is an excellent source to produce plywood boards. Wastes from mechanical processing of birch wood are suitable to produce composite materials. Granulometric analyses of chips from sawing processes on the PRW 15M frame saw,...
-
International Workshops on First-Order Theorem Proving
Conferences -
Integrable zero-range potentials in a plane
PublicationWe examine general statements in the Wronskian representation of Darboux transformations for plane zero-range potentials. Such expressions naturally contain scattering problem solution. We also apply Abel theorem to Wronskians for differential equations and link it to chain equations for Darboux transforms to fix conditions for further development of the underlying distribution concept. Moutard transformations give a convenient...
-
The Quality of Life and Satisfaction with Continuous Glucose Monitoring Therapy in Children under 7 Years of Age with T1D Using the rtCGM System Integrated with Insulin Pump—A Caregivers Point of View
Publication -
Critical Remarks on Landauer’s principle of erasure– dissipation: Including notes on Maxwell demons and Szilard engines
PublicationWe briefly address Landauer’s Principle and some related issues in thermal demons. We show that an error-free Turing computer works in the zero-entropy limit, which proves Landauer’s derivation incorrect. To have a physical logic gate, memory or information-engine, a few essential components necessary for the operation of these devices are often neglected, such as various aspects of control, damping and the fluctuation–dissipation...
-
Attractors of dissipative homeomorphisms of the infinite surface homeomorphic to a punctured sphere
PublicationA class of dissipative orientation preserving homeomorphisms of the infinite annulus,pairs of pants, or generally any infinite surface homeomorphic to a punctured sphere isconsidered. We prove that in some isotopy classes the local behavior of such homeomor-phisms at a fixed point, namely the existence of so-called inverse saddle, impacts thetopology of the attractor — it cannot be arcwise connected
-
The cohomological span of LS-Conley index
PublicationIn this paper we introduce a new homotopy invariant – the cohomological span of LS-Conley index. We prove the theorems on the existence of critical points for a class of strongly indefinite functionals with the gradient of the form Lx+K(x), where L is bounded linear and K is completely continuous. We give examples of Hamiltonian systems for which our methods give better results than the Morse inequalities. We also give a formula...
-
Speed Observer Structure of Induction Machine Based on Sliding Super-Twisting and Backstepping Techniques
PublicationThis paper presents an analysis of the two speed observer structures which are based on the backstepping and sliding super twisting approach. The observer stabilizing functions result from the Lyapunov theorem. To obtain the observer tuning gains the observer structure is linearized near the equilibrium point. The rotor angular speed is obtained from non-adaptive dependence. In the sensorless control system structure the classical...
-
The Global Boundary Stratotype Section and Point (GSSP) for the base of the Coniacian Stage (Salzgitter-Salder, Germany) and its auxiliary sections (Słupia Nadbrzeżna, central Poland; Střeleč, Czech Republic; and El Rosario, NE Mexico)
Publication -
International Conference on Theorem Proving with Analytic Tableaux and Related Methods
Conferences -
Conference on Interactive Theorem Proving (previously TPHOLs, changed in 2009)
Conferences -
Rainscreen panels deformations mods
PublicationIn rainscreen panels designing simplified calculation models are used. For plate computation simply supported panels or panels with fixed edges are commonly used. Such approximations are subjected to large errors that lead to inefficient rainscreen panels design. In order to develop a method for determining the optimal geometry of the rainscreen panels, that would take into consideration the real stiffness of both continuous and...
-
Existence and uniqueness of solutions for single-population McKendrick-von Foerster models with renewal
PublicationWe study a McKendrick-von Foerster type equation with renewal. This model is represented by a single equation which describes one species which produces young individuals. The renewal condition is linear but takes into account some history of the population. This model addresses nonlocal interactions between individuals structured by age. The vast majority of size-structured models are also treatable. Our model generalizes a number...
-
Piotr Chrzan prof. dr hab. inż.
PeopleUrodził się w 1954 r. w Sopocie. Jest absolwentem Wydziału Elektroniki Politechniki Gdańskiej (1978). W 1980 r. podjął pracę na Wydziale Elektrycznym w zespole prof. Jerzego Jaczewskiego. W 1988 r. uzyskał stopień naukowy doktora nauk technicznych, habilitację w 1999 r., w zakresie elektrotechniki: energoelektroniki i automatyki napędu, a tytuł profesora w 2017 r. Był promotorem 6 obronionych prac doktorskich (w tym 3 z wyróżnieniem)....
-
Constructive Controllability for Incompressible Vector Fields
PublicationWe give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen...
-
A note on simple bifurcation of equilibrium forms of an elastic rod on a deformable foundation
PublicationWe study bifurcation of equilibrium states of an elastic rod on a two-parameter Winkler foundation. In the article "Bifurcation of equilibrium forms of an elastic rod on a two-parameter Winkler foundation" [Nonlinear Anal., Real World Appl. 39 (2018) 451-463] the existence of simple bifurcation points was proved by the use of the Crandall-Rabinowitz theorem. In this paper we want to present an alternative proof of this fact based...
-
Minimal number of periodic points of smooth boundary-preserving self-maps of simply-connected manifolds
PublicationLet M be a smooth compact and simply-connected manifold with simply-connected boundary ∂M, r be a fixed odd natural number. We consider f, a C1 self-map of M, preserving ∂M . Under the assumption that the dimension of M is at least 4, we define an invariant Dr(f;M,∂M) that is equal to the minimal number of r-periodic points for all maps preserving ∂M and C1-homotopic to f. As an application, we give necessary and sufficient...
-
Paweł Szymon Dąbrowski dr inż.
PeopleDr. Eng. Paweł Szymon Dąbrowski studied geodesy and cartography at the University of Warmia and Mazury in Olsztyn from 2004-2009, where he obtained the title of Master of Science in Engineering. In the years 2009-2016, he worked as a land surveyor in Iława and Gdańsk. He gained professional experience during the construction of the Pomeranian Metropolitan Railway, which helped him obtain a national surveying license in 2015. In...
-
An algorithmic approach to estimating the minimal number of periodic points for smooth self-maps of simply-connected manifolds
PublicationFor a given self-map f of M, a closed smooth connected and simply-connected manifold of dimension m 4, we provide an algorithm for estimating the values of the topological invariant D^m_r [f], which equals the minimal number of r-periodic points in the smooth homotopy class of f. Our results are based on the combinatorial scheme for computing D^m_r [f] introduced by G. Graff and J. Jezierski [J. Fixed Point Theory Appl. 13 (2013),...
-
The saga of a fish: from a survival guide to closing lemmas
PublicationIn the paper by D. Burago, S. Ivanov and A. Novikov, “A survival guide for feeble fish”, it has been shown that a fish with limited velocity can reach any point in the (possibly unbounded) ocean provided that the fluid velocity field is incompressible, bounded and has vanishing mean drift. This result extends some known global controllability theorems though being substantially nonconstructive. We give a fish a different recipe...
-
Hossein Nejatbakhsh Esfahani Dr.
PeopleMy research interests lie primarily in the area of Learning-based Safety-Critical Control Systems, for which I leverage the following concepts and tools:-Robust/Optimal Control-Reinforcement Learning-Model Predictive Control-Data-Driven Control-Control Barrier Function-Risk-Averse Controland with applications to:-Aerial and Marine robotics (fixed-wing UAVs, autonomous ships and underwater vehicles)-Multi-Robot and Networked Control...
-
The development of an underwater telephone for digital communication purposes
PublicationThe underwater telephone HTL-10 has been designed to provide voice and data communication between helicopter and submarines using acoustic waves. It works in a half-duplex mode and uses analogue power-efficient modulation in the form of a single side-band, suppressed carrier, in a wide range of frequencies. It generates the transmitted signal, and processes the received signals. It is implemented with the use of digital signal...
-
Wybrane problemy plastyczności w płaskim ośrodku mikropolarnym
PublicationW pracy analizuje się sprężysto-plastyczny płaski ośrodek mikropolarny. Do rozwiązań równań plastyczności wykorzystuje się technikę Closest Point Projection Method. Przedstawiono przykład numeryczny w płaskim stanie naprężenia, zasygnalizowano problem lokalizacji w zadaniach z osłabieniem materiału.
-
Patryk Ziółkowski dr inż.
PeopleAssistant Professor at Gdansk Tech. He participated in international projects, including projects for the Ministry of Transportation of the State of Alabama (2015), he is also the winner of a grant from the Kosciuszko Foundation for conducting research in the USA, which he completed in 2018. An expert in the field of artificial intelligence. His main area of research interest is the application of artificial intelligence in Civil...
-
Technological substitution in Asia
PublicationThis book provides extensive evidence on information and communication technologies development diffusion patterns, unveils specific ‘network effects’ that enhance rapid spread of ICT, and detect major macroeconomic determinants of this process, across 36 Asian economies over the period 1980-2015. Moreover, this research traces country-specific patterns of the unique process. We consider two types of technological substitution,...
-
Kazimierz Kosmowski prof. dr hab. inż.
PeopleKazimierz Tadeusz Kosmowski (ur. 12 maja 1947 r. w Nakle nad Notecią) – specjalizacja z zakresu niezawodności i bezpieczeństwa systemów technicznych. Prowadzi badania dotyczące metod identyfikacji zagrożeń oraz analizy i oceny ryzyka ukierunkowanych na obiekty przemysłowe i systemy infrastruktury krytycznej w cyklu życia. Aktualne zainteresowania naukowe dotyczą współdziałania systemów OT i IT oraz bezpieczeństwa funkcjonalnego...
-
Modeling of entrained flow steam gasification of sewage sludge
PublicationProper management of sewage sludge becomes increasingly problematic due to legal requirements aiming at diminishing environmental impact, as well as rationalizing the utilization from the point of view of logistics. Steam gasification of sewage sludge can result in very good quality of the producer gas. So far, the works have been focused on the gasification in fixed bed gasifiers. However, this does not allow to take full advantage...
-
Study on population dynamics for triple-linked food chain using a simulation-based approach
PublicationThe procedures based on simulation have become a feasible testing method that does not require investing valuable resources to create a concrete prototype, especially with the increasing computational power of computers. Thus, design changes can be adopted and design errors can be fixed before it is too late. Simulation turns to be a cheap, safe and often more acceptable from an ethical perspective. In our work we summarize the...
-
ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART III DIMENSIONAL ANALYSIS
PublicationThis article presents the third and last part of the problem of diagnosing the fatigue of marine propulsion shafts in terms of energy with the use of the action function, undertaken by the authors. Even the most perfect physical models of real objects, observed under laboratory conditions and developed based on the results of their research, cannot be useful in diagnostics without properly transferring the obtained results to the...
-
Evaluation of RTKLIB's Positioning Accuracy Using low-cost GNSS Receiver and ASG-EUPOS
PublicationThe paper focuses on a comparison of different positioning methods provided by free and open source software (FOSS) package called RTKLIB. The RTKLIB supports real‐time and post‐processed positioning. The most important modes of operation tested by the authors are Kinematic, Static, Fixed and Precise Point Positioning (PPP). The data for evaluation were obtained from low‐cost Global Navigation Satellite System (GNSS) receiver....
-
Influence of sheet/purlin fasteners spacing on shear flexibility of the diaphragm
PublicationThe paper presents the influence of sheet/purlin fasteners location (in reference to trapezoidal profile cross section) on shear flexibility of the cladding acting as a diaphragm. Analytical procedures were presented and their limitations were discussed. Next, selected schemes of fasteners location, known from engineering practice, but not included in European codes and recommendations, were analysed numerically in order to observe...
-
Comparative analysis of the theoretical models of ideal propulsor, ideal fluid brake, ideal screw propeller and ideal axial wind turbine
PublicationThe article presents a detailed discussion of four different fluid dynamics devices.These devices are presented with all relevant mathematical formulae regarding the forces, the power and the efficiency. It is demonstrated that application of the Betz theorem to axial wind turbines is not correct and it underestimates the maximujm achievable efficiency. This conclusion is supported by numerical calculations.
-
Simulation of unsteady flow over floodplain using the diffusive wave equation and the modified finite element method
PublicationWe consider solution of 2D nonlinear diffusive wave equation in a domain temporarily covered by a layer of water. A modified finite element method with triangular elements and linear shape functions is used for spatial discretization. The proposed modification refers to the procedure of spatial integration and leads to a more general algorithm involving a weighting parameter. The standard finite element method and the finite difference...
-
Periodic Solutions of Generalized Lagrangian Systems with Small Perturbations
PublicationIn this paper we study the generalized Lagrangian system with a small perturbation. We assume the main term in the system to have a maximum, but do not suppose any condition for perturbation term. Then we prove the existence of a periodic solution via Ekeland’s principle. Moreover, we prove a convergence theorem for periodic solutions of perturbed systems.
-
Research of hydrotronic variable displacement radial piston pump with electro -pneumatic control
PublicationThe paper presents the developed new electro-pneumatic control (pneumotronic) system for hydraulic fixed-displacement radial piston pump. Hydraulic fixed-displacement radial piston pump equipped with the proposed control system changes into hydrotronic variable-displacement radial piston pump. Pump flow rate control is realized by means of programmable logic controller, electro-pneumatic valves, pneumatic cylinders and a sensor.
-
Module structure in Conley theory with some applications
PublicationA multiplicative structure in the cohomological versjon of Conley index is described . In the case of equivariant flows we apply the normalization procedure known from equivariant degree theory and we propose a new continuation invariant. The theory is then applied to obtain a mountain pass type theorem. Another application is a result on multiple bifurcations for some elliptic PDE.
-
Mountain pass type periodic solutions for Euler–Lagrange equations in anisotropic Orlicz–Sobolev space
PublicationUsing the Mountain Pass Theorem, we establish the existence of periodic solution for Euler–Lagrange equation. Lagrangian consists of kinetic part (an anisotropic G-function), potential part and a forcing term. We consider two situations: G satisfying at infinity and globally. We give conditions on the growth of the potential near zero for both situations.
-
S7-DK7 Myślenice Zakopane 2017 - video data
Open Research DataThe video cameras installed on the Expressway S7: 6 cameras in both directions, location: main road registered vehicles along the entire length of the road section. Cameras were mounted on 5-7 meter high masts. Date 11-15.08.2017
-
Positive solutions to Sturm–Liouville problems with non-local boundary conditions
PublicationIn this paper, the existence of at least three non-negative solutions to non-local boundary-value problems for second-order differential equations with deviating arguments α and ζ is investigated. Sufficient conditions, which guarantee the existence of positive solutions, are obtained using the Avery–Peterson theorem. We discuss our problem for both advanced and delayed arguments. An example is added to illustrate the results.
-
Poprawa stanu dynamicznego hydrozespołu. W: [CD-ROM] Materiały konferencyj- ne. Turbiny Wodne - Niezawodność i Ekologia. Gdańdsk, 9 grudnia 2003. Gdańsk: TEW, KKiEM P. Gdań., A&O EXPERT**2003, wykład oraz prezentacja elektroniczna z wykorzyst. Programu Power Point + wydr. 17 s.
PublicationWspółczesna technika pomiarowa coraz częściej wykrywa pojawienie się drgań względnych czopa względem panwi o częstotliwości zbliżonej do 1/2X, wywołanych tak zwanym wirem olejowym. Drgania te w dłuższym okresie czasu prowadzą do zmęczeniowego uszkodzenia powierzchni ślizgowej łożyska a w konsekwencji do awarii łożyska. Jednym ze sposobów eliminacji tych drgań jest zastosowa-nie dociążenia geometrycznego w łożyskach prowadzących...
-
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...