2011 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2011

Pokaż wszystkie

Olfactory and tissue markers of fear in mammals including humans
- Roman Hauser
- Marek Wiergowski
- Michał Kaliszan
- Tomasz Gos
- Gerhatd Kernbach-Wighton
- Michał Studniarek
- Zbigniew Jankowski
- Jacek Namieśnik
2011 MEDICAL HYPOTHESES
W pracy przedstawiono informacje na temat:-klasyfikacji i budowy chemicznej związków chemicznych zaliczanych do grupy feromonów,-ich rola w funkcjonowaniu organizmów żywych w tym także organizmu ludzkiego,wyników badań prowadzonych z wykorzystaniem komory ekspozycyjnej własnej konstrukcji,metodyk analitycznych wykorzystywanych do oznaczania śladowych zawartości feromonów w próbkach wydychanego powietrza.
On a Method of Efficiency Increasing in Kaplan Turbine
- Marzena Banaszek
- Krzysztof Tesch
2011 Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
This paper presents a method of increasing efficiency in Kaplan-type turbine. The method is based on blade profile optimisation together with modelling the interaction between rotor and stator blades. Loss coefficient was chosen as the optimisation criterion, which is related directly to efficiency. Global optimum was found by means of Genetic Algorithms, and Artificial Neural Networks were utilised for approximations to reduce long calculation time.
On cooperative image denoising
- Maciej Niedźwiecki
- Szymon Gackowski
2011
In this paper we suggest how several competing image denoising algorithms, differing in design parameters, or even in design principles, can be combined together to yield a better and more reliable denoising algorithm. The proposed fusion mechanism allows one to combine practically all kinds of noise reduction tools. It also allows one to account for the distribution of measurement noise, and in particular - to cope with heavy-tailed disturbances, such as Laplacian noise, or light-tailed disturbances, such as uniform noise.
On degradation of glass/polyester laminate immersed in water
- Michał Landowski
- Michał Budzik
- Krystyna Imielińska
2011 Pełny tekst Advances in Materials Science
Mechanical behaviour was compared for glass/ polyester laminates manufactured in the boatbuilding plant using three methods: hand lay-up, vacuum bagging, infusion. Specimens were tested in dry condition and following accelerated water immersion test (70°C- corresponding to the exposure of 30 years at 19°C). In three point bending test 40-50% reduction in laminate strength was observed due to water immersion. The highest degradation was in samples manufactured using hand lay-up method, the differences in strength between both vacuum methods were insignificant. Interlaminar shear strength was reduced by 25% for infusion method which is recommended as the most efficient. Matrix plasticization and debondings as well as surface microcracks were responsible for reduction in strength for water conditioned specimens. However, no microstructural difference in type or intensity of internal damage was observed for the three sample types.
On elasto-plastic analysis of thin shells with deformable junctions
- Jacek Chróścielewski
- Violetta Konopińska-Zmysłowska
- Wojciech Petraszkiewicz
2011
Przedstawiono nieliniowe warunki równowagi nieregularnej cienkiej powłoki w oparciu o zasadę prac wirtualnych. Wyprowadzono dwu-wymiarowe zależności konstytutywne w zakresie sprężysto-plastycznego zachowania sie powłoki poprzez podzial powłoki na n warstw oraz całkowanie trój-wymiarowych zależności konstytutywnych po wszystkich warstwach. Jako przykład przeanalizowano ciśnieniowe urządzenie pomiarowe z uwzględnieniem odkształcalności połączeń.
On homotopy Conley index for multivalued flows in Hilbert spaces
- Zdzisław Dzedzej
- Grzegorz Gabor
2011 Pełny tekst Topological Methods in Nonlinear Analysis
Podano aproksymacyjną definicję indeksu homotopijnego, otrzymując naturalne związki z podobnymi niezmiennikami. Zbadano własności tego niezmiennika i zastosowano do badania gradientowych potoków wykazując pewne geometryczne własności zbiorów niezmienniczych
On modelling and non-linear elasto-plastic analysis of thin shells with deformable junctions
- Jacek Chróścielewski
- Violetta Konopińska-Zmysłowska
- Wojciech Pietraszkiewicz
2011 ZAMM-Zeitschrift fur Angewandte Mathematik und Mechanik
The undeformed base surface of the irregular thin shell is modelled by the union of a finite number of regular smooth surface elements joined together along spatial curvilinear surface edges. The equilibrium conditions are formulated by postulating an appropriate form of the principle of virtual work, where also deformability of shell junctions is taken into account. The PVW is then discretised by C1 finite elements and the incremental-iterative procedure is applied to solve the highly non-linear BVP. As an example, the axisymmetric deformation state is calculated in the casing of devise measuring the external pressure and having two pairs of circular welded junctions. The problem is solved within the elasto-plastic range of material behaviour with linear combination of isotropic and kinematic hardening, and deformability of the junctions is taken into account.
On neutral differential equations and the monotone iterative method
- Tadeusz Jankowski
- Robert Jankowski
2011 DYNAMIC SYSTEMS AND APPLICATIONS
The application of the monotone iterative method to neutral differential equations with deviating arguments is considered in this paper. We formulate existence results giving sufficient conditions which guarantee that such problems have solutions. This approach is new and to the Authors' knowledge, this is the first paper when the monotone iterative method is applied to neutral first-order differential equations with deviating arguments. An example is given to illustrate theoretical results. One may apply a numerical method based on the proposed monotone iterative method to obtain a numerical solution of our problems.
On noncausal identification of nonstationary stochastic systems
- Maciej Niedźwiecki
- Szymon Gackowski
2011
In this paper we consider the problem of noncausal identification of nonstationary,linear stochastic systems, i.e., identification based on prerecorded input/output data. We show how several competing weighted least squares parameter smoothers, differing in memory settings, can be combined together to yield a better and more reliable smoothing algorithm. The resulting parallel estimation scheme automatically adjusts its smoothing bandwidth to the unknown, and possibly time-varying, rate of nonstationarity of the identified system. It also allows one to account for the distribution of measurement noise, and in particular - to cope with heavy-tailed disturbances, such as Laplacian noise, or light-tailed disturbances, such as uniform noise.
On noncausal weighted least squares identification of nonstationary stochastic systems
- Maciej Niedźwiecki
- Szymon Gackowski
2011 AUTOMATICA
In this paper, we consider the problem of noncausal identification of nonstationary, linear stochastic systems, i.e., identification based on prerecorded input/output data. We show how several competing weighted (windowed) least squares parameter smoothers, differing in memory settings, can be combined together to yield a better and more reliable smoothing algorithm. The resulting parallel estimation scheme automatically adjusts its smoothing bandwidth to the unknown, and possibly time-varying, rate of nonstationarity of the identified system. We optimize the window shape for a certain class of parameter variations and we derive computationally attractive recursive smoothing algorithms for such an optimized case.
On quasi-compact Markov nets
- Wojciech Bartoszek
- Nazife Erkursun
2011 ERGODIC THEORY AND DYNAMICAL SYSTEMS
Analizuje się strukturę ergodyczną netów Markowa. W szczególności podano charakteryzację ściśle ergodycznych minimalnych (L-R) netów markowskich na zwartej przestrzeni fazowej. Uzyskano warunki równoważne quasi-zwartości (L-R) netów Markowa, rozszerzając tzw. ergodyczne twierdzenie Lotz'a.
On stability of iodine doped TiO2 electrodes in pH varied aqueous electrolytes
- Katarzyna Szybowska
- Anna Lisowska-Oleksiak
2011 SOLID STATE IONICS
W pracy przedstaiono charakterystykę elektrochemiczną warstwy domieszkowanego jodem TiO2 na podłożu platynowym. Wyniki badań prowadzone w elektrolitach o różnym pH pozowoliły na określenie właściwości na granicy faz elektroda - elektrolit. Wyznaczono zależność potencjału pasma płaskiego od pH elektrolitu, a charakter otrzymanej funkcji potwirdził stabilność proszku I-TiO2 w kontakcie s roztworem.
On structural physical approximations and entanglement breaking maps
- Remigiusz Agusiak
- Bae Joonwoo
- Łukasz Czekaj
- Lewenstein Maciej
2011 JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL
Very recently, a conjecture saying that the so-called structural physical approximations (SPAs) to optimal positive maps (optimal entanglement witnesses) give entanglement breaking (EB) maps (separable states) has been posed (Korbicz et al 2008 Phys. Rev. A 78 062105). The main purpose of this contribution is to explore this subject. First, we extend the set of entanglement witnesses supporting the conjecture. Then, we ask whether SPAs constructed from other than the depolarizing channel maps also lead to EB maps and show that in general this is not the case. On the other hand, we prove an interesting fact that for any positive map A, there exists an EB channel F such that the SPA of A constructed with the aid of F is again an EB channel. Finally, we ask similar questions in the case of continuous variable systems. We provide a simple way of constructing SPA and prove that in the case of the transposition map it gives the EB channel.
On the derivative of the associated Legendre function of the first kind of integer order with respect to its degree (with applications to the construction of the associated Legendre function of the second kind of integer degree and order).
- Radosław Szmytkowski
2011 JOURNAL OF MATHEMATICAL CHEMISTRY
Wyprowadzono szereg zamkniętych wyrażeń dla pochodnych stowarzyszonej funkcji Legendre'a pierwszego rodzaju względem jej dolnego indeksu w przypadku, gdy górny indeks jest liczbą całkowitą. Wyniki zastosowano do znalezienia pewnych nowych reprezentacji (w tym typu Rodriguesa) stowarzyszonych funkcji Legendre'a drugiego rodzaju o indeksach całkowitych.
On the instantaneous frequency smoothing for signals with quasi-linear frequency changes
- Maciej Niedźwiecki
- Michał Meller
2011
The problem of estimation of the slowly-varying instantaneous frequency of a nonstationary complex sinusoidal signal buried in noise is considered. This problem is usually solved using frequency tracking algorithms. It is shown that the accuracy of frequency estimates can be considerably increased if the results yielded by the frequency tracker are further processed using the appropriately designed filters. The resulting frequency smoother can be employed in many off-line applications. Whenever signal frequency varies in a sufficiently smooth manner, the proposed algorithm, based on a new, quasi-linear model of frequency changes, outperforms the existing solutions.
On the metric dimension of corona product graphs
- Ismael G Yero
- Dorota Kuziak
- Juan A. RODRíGUEZ-VELáZQUEZ
2011 Pełny tekst COMPUTERS & CHEMICAL ENGINEERING
We give several results on the metric dimension of corona product graphs.
On the mixing property and the ergodic principle for nonhomogeneous Markov chains
- Małgorzata Pułka
2011 Pełny tekst LINEAR ALGEBRA AND ITS APPLICATIONS
W pracy rozważane są różne typy zachowania granicznego nieskończenie wymiarowych niejednorodnych łańcuchów Markowa z czasem dyskretnym. Badana jest struktura geometryczna zbioru łańcuchów Markowa w normowej i mocnej topologii operatorowej.
On the Structure of Time in Computational Semantics of a Variable-Step Solver for Hybrid Behavior Analysis
- Justyna Zander
- Pieter J. Mosterman
- Gregoire Hamon
- Ben Denckla
2011
Hybrid dynamic systems combine continuous and discrete behavior. Often, computational approaches are employed to derive behaviors that approximate the analytic solution. An important part of this is the approximation of differential equation behavior by numerical integration. The accuracy and computational efficiency of the integration usually depend on the complexity of the method and its implicated approximation errors, especially when repeated over iterations. This work formally defines the computational semantics of a solver in a denotational sense so as to analyze discrete- and continuous-time behavior of time-based block diagram models. A stream-based approach is used to analyze the numerical integration implemented by the solver. The resulting solver applies the principle of nonmonotonic time, which means that every new evaluation of values is computed in a temporally nonmonotonic manner. This allows for shifting the evaluation points backward and forward in time. A partially ordered structure is recovered based on the concept of stratification. Solver dynamics are thus made explicit and can be studied in concert with behavior of discontinuous models parts
On the tendency of temperature and electric field dependences of interface recombination in P3HT:PCBM organic bulk heterojunction solar cells
- Jędrzej Szmytkowski
2011 SEMICONDUCTOR SCIENCE AND TECHNOLOGY
We demonstrate theoretical explanation of the temperature and electric field dependences of recombination coefficients in an organic P3HT:PCBM bulk heterojunction solar cell. Based onthe model of interface recombination, two analytical formulas describing the relative ratio of the interface (γI ) to the Langevin (γL) recombination coefficients have been derived. Our analysis indicates that the sign of parameters φT and φF determines the increasing or decreasing of γI /γL with temperature and electric field. We have obtained satisfactory agreement between theoretical calculations and experimental data. Additionally, the presented model is capable of explaining, for the first time, the fact that the ratio of the experimental recombination coefficient with sum of charge carrier mobilities increases with electric field.
On trees with double domination number equal to total domination number plus one
- Marcin Krzywkowski
2011 Pełny tekst ARS COMBINATORIA
A total dominating set of a graph G is a set D of vertices of G such that every vertex of G has a neighbor in D. A vertex of a graph is said to dominate itself and all of its neighbors. A double dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D. The total (double, respectively) domination number of a graph G is the minimum cardinality of a total (double, respectively) dominating set of G. We characterize all trees with double domination number equal to total domination number plus one.