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Tytuł:
A unified approach to stability analysis of switched linear descriptor systems under arbitrary switching
Autorzy:
Zhai, G.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/907764.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
układ komutowany
układ deskrypcyjny
stabilność
komutacja dowolna
nierówność macierzy
LMI
switched linear descriptor systems
stability
arbitrary switching
linear matrix inequalities (LMIs)
common quadratic Lyapunov functions
Opis:
We establish a unified approach to stability analysis for switched linear descriptor systems under arbitrary switching in both continuous-time and discrete-time domains. The approach is based on common quadratic Lyapunov functions incorporated with linear matrix inequalities (LMIs). We show that if there is a common quadratic Lyapunov function for the stability of all subsystems, then the switched system is stable under arbitrary switching. The analysis results are natural extensions of the existing results for switched linear state space systems.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2010, 20, 2; 249-259
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A stability based neural networks controller design method
Autorzy:
Song, J.
Xu, X.
He, X.
Powiązania:
https://bibliotekanauki.pl/articles/206120.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sieć neuronowa
stabilność
sterowanie nieliniowe
neural networks control
nonlinear control
sliding mode
stability
Opis:
The use of neural networks in control systems can be seen as a natural step in the evolution of control methodology to meet new challenges. Many attempts have been made to apply the neural networks to deal with non-linearities and uncertainties of the control systems. Research in neural network applications to control can be classified according to the major methods depending on structures of the control system, such as NN-based NON-linear System Identification, NN-based Supervised Control, NN-based Direct Control, NN-based Indirect Control, NN-based Adaptive Control, NN-based Self-learning Control, NN-based Fuzzy Control, and NN Variable Structure Control. All these control methods cannot, however, effectively guarantee system stability, i.e. none of these neural network controls, except for NN-based Variable Structure Control, is based on system stability. This also limits the application and development of the neural networks in control theory. The paper shows the effort to solve this difficulty and give a way for the design method of the stability based neural networks controller using Lyapunov second stability theorem. This kind of controller can not only guarantee system stability, but also fully compensate for the influence of system uncertainties and non-linearities.Simulation results also show the effectiveness of the controller.
Źródło:
Control and Cybernetics; 1998, 27, 1; 119-133
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of Ship Collision Risk Index Based on Complex Plane and Its Realization
Autorzy:
Xu, X.
Geng, X.
Wen, Y.
Powiązania:
https://bibliotekanauki.pl/articles/116223.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
risk
risk calculation
ship collision risk index
risk index
ships domain
Decision Support System (DSS)
modeling of ship collision risk index
ARPA
Opis:
Ship collision risk index is the basic and important concept in the domain of ship collision avoidance. In this paper, the advantages and deficiencies of the various calculation methods of ship collision risk index are pointed out. Then the ship collision risk model based on complex plane, which can well make up for the deficiencies of the widely-used evaluation model proposed by Kearon.J and Liu ruru is proposed. On this basis, the calculation method of collision risk index under the encountering situation of multi-ships is constructed, then the three-dimensional image and spatial curve of the risk index are figured out. Finally, single chip microcomputer is used to realize the model. And attaching this single chip microcomputer to ARPA is helpful to the decision-making of the marine navigators.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2016, 10, 2; 251-256
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decoupling control for permanent magnet in-wheel motor using internal model control based on back-propagation neural network inverse system
Autorzy:
Li, Y.
Zhang, B.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/200933.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electric vehicle
permanent magnet in-wheel motor
back-propagation neural network
inverse system
internal model control
pojazd elektryczny
silnik z napędem na magnesy stałe
inwersja systemu
propagacja wsteczna
model odwrotny
system odwrotny
Opis:
The permanent magnet in-wheel motor (PMIWM) is a nonlinear, multivariable, strongly coupled and highly complex system. The key to the development and application of the PMIWM consists in the improvement of its control accuracy and dynamic performance. In order to effectively decouple the PMIWM, this paper presents a novel internal model control (IMC) approach based on the back-propagation neural network inverse (BPNNI) control method. First, theoretical analysis is conducted to show the existence of the PMIWM inverse system, to be modeled mathematically. The inverse system approximated and identified by the back-propagation neural network (BPNN) constitutes the back-propagation neural network inverse (BPNNI) system. Then, by cascading the BPNNI system on the left side of the original PMIWM system, a new decoupling, pseudo-linear system is established. Moreover, the 2-DOF internal model control (IMC) method is employed to design the extra closed-loop controller that further improves disturbance rejection and robustness of the whole system. Consequently, the proposed decoupling control approach incorporates the advantages of both the BPNNI and the IMC. Effectiveness of thus proposed control approach is verified by means of simulation and real-time hardware-in-the-loop (HIL) experiments.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 6; 961-972
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Band Model in Monte Carlo Simulation of Electric Transport in ZnS Thin Film Electroluminescent Devices
Autorzy:
Zhao, H.
Wang, Y.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/2014087.pdf
Data publikacji:
2000-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.-b
72.20.-i
Opis:
In this paper, an analytical band model is introduced in Monte Carlo simulation of electric transport process in thin film electroluminescent devices. The band structure of ZnS calculated from the empirical pseudopotential method is fitted by using polynomials. The density of states and scattering rates are also calculated from these polynomials. Based on these results, the electric transport process in ZnS-type thin film electroluminescent devices is simulated through the Monte Carlo method. By comparison with others, this model is as fast as the nonparabolic model and as accurate as the full band model. Furthermore, the influence of the band model on the simulation results is also investigated. We show that the dispersion relation and density of states are all important in the simulation.
Źródło:
Acta Physica Polonica A; 2000, 98, 1-2; 123-130
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research and application of rule updating mining algorithm for marine water quality monitoring data
Autorzy:
Sun, Q
Zhang, J.
Xu, X
Powiązania:
https://bibliotekanauki.pl/articles/258822.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine water quality monitoring
database updating
data mining
rule updating
Opis:
This paper studies the characteristics of marine water quality monitoring data monitored by photoelectric sensor network, mines the potential information from the massive data. on account of the continuous accumulation of monitoring data, this paper focuses on the study of database with numerical attribute and proposes a rule updating algorithm for solving the rule maintenance issues caused by changes in the database. according to the rule, the algorithm forms a new database from part of the original data and the new data, and searches the new database by random search, thus can avoid creating a large number of redundant rules and can quickly mine effective rules at the same time. experimental results show that this method not only can avoid mining in the whole original massive data, but also can improve work efficiency, and can quickly and effectively find new data and find useful rules in the data with high practicability.
Źródło:
Polish Maritime Research; 2018, S 3; 136-140
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Buckling of cylindrical shells under external pressure in a Hamiltonian system
Autorzy:
Sun, J.
Xu, X.
Lim, C. W.
Powiązania:
https://bibliotekanauki.pl/articles/280390.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
buckling
cylindrical shells
external pressure
Hamiltonian system
Opis:
In this article, the elastic buckling behavior of cylindrical shells under external pressure is studied by using a symplectic method. Based on Donnell’s shell theory, the governing equations which are expressed in stress function and radial displacement are re-arranged into the Hamiltonian canonical equations. The critical loads and buckling modes are reduced to solving for symplectic eigenvalues and eigenvectors. The buckling solutions are mainly grouped into four categories according to the natures of the buckling modes. The effects of geometrical parameters and boundary conditions on the buckling loads and modes are examined in detail.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 3; 641-653
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
How Clean is Clean Enough? Maintaining Thermal Protective Clothing Under Field Conditions in the Oil and Gas Sector
Autorzy:
Crown, E. M.
Feng, A.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/90475.pdf
Data publikacji:
2004
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
protective clothing
decontamination
flammability
przemysł wydobywczy
gaz kopalniany
odzież ochronna
izolacja cieplna
tkaniny na odzież ochronną
Opis:
The purpose of this research was to develop practical care procedures to help maintain the protective quality of flame resistant workwear laundered by workers in the field. Based on observed field conditions, experiments were conducted that simulated domestic laundry procedures. The first experiment involved two flame resistant (FR) fabrics, contaminated or not contaminated with oil. Independent variables also included detergent type and laundry pre-treatment. Other laundry parameters were controlled. Results indicated that it is easier to maintain the FR performance of the FR-treated blend than it is for the aramid fabric. It is hypothesized that energy generated by initial ignition of oil on the specimens triggers the FR mechanism of the treatment, which in turn inhibits further combustion. A second experiment using larger specimens and a domestic washing machine also supported the hypothesized mechanism.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2004, 10, 3; 247-254
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined load buckling for cylindrical shells based on a symplectic elasticity approach
Autorzy:
Sun, J.
Xu, X.
Lim, C. W.
Powiązania:
https://bibliotekanauki.pl/articles/281463.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
buckling mode
combined loads
critical load
cylindrical shell
symplectic method
Opis:
Buckling behavior of cylindrical shells subjected to combined pressure, torsion and axial compression is presented by employing a symplectic method. Both symmetric and non- -symmetric boundary conditions are considered. Hamiltonian canonical equations are established by introducing four pairs of dual variables. Then, solution of fundamental equations is converted into a symplectic eigenvalue problem. It is concluded that the influence of pressure on buckling solutions is more significant than that due to compressive load, in particular for a longer external pressured cylindrical shell. Besides, buckling loads and circumferential wavenumbers can be reduced greatly by relaxed in-plane axial constraints.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 705-716
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-uniform illumination correction based on the retinex theory in digital image correlation measurement method
Autorzy:
Gu, G.
She, B.
Xu, G.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/173506.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital image correlation (DIC)
non-uniform illumination correction
retinex theory
deformation measurement
Opis:
Digital image correlation is a well-known optical measurement method for full-field deformation and strain measurements. The quality of speckle images used in digital image correlation calculation can directly affect the measurement accuracy of digital image correlation. In most practical measurement circumstances, a uniform illumination environment is usually required to illuminate the detected object in order to capture speckle images upon different deformed states with uniform background intensity. However, the tested object becomes so large that the adopted light source cannot cover all the interested area with uniform illumination, and the speckle images acquired by CCD camera may have non-uniform background intensity distributions. In this paper, the influence of non-uniform illumination is first analyzed in detail by means of a comparison of experimental results of digital image correlation using speckle patterns with both uniform and non-uniform intensity distributions. Then, a new correctional method based on the combination of the basic retinex theory and the illumination formulae of a point light source is proposed. Finally, a real experiment with non-uniform illumination is implemented to verify the effectiveness of this method.
Źródło:
Optica Applicata; 2017, 47, 2; 199-208
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous measurement of refractive index and thickness for optically transparent object with a dual-wavelength quantitative technique
Autorzy:
Xu, X.
Wang, Y.
Xu, Y.
Jin, W.
Powiązania:
https://bibliotekanauki.pl/articles/174666.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital holography
phase measurement
cell measurement
red blood cell
Opis:
We present a new dual-wavelength quantitative measurement approach that can be employed for simultaneously measuring both the refractive index and the thickness of the homogenous specimen. This method is realized by dual-wavelength in-line phase-shifting digital holography, and then the phase images are obtained by using four-phase step algorithm for each wavelength separately. Based on computer simulation technology, the feasibility and the effectiveness of our proposed method are demonstrated by comparing our simulation results with the experimental results of the spherical silica bead and the red blood cell, respectively. Our work will provide some guidance in the experimental research for transparent phase objects.
Źródło:
Optica Applicata; 2016, 46, 4; 597-605
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intervalley Transfer of Electrons in ZnS-Type Thin Film Electroluminescent Devices
Autorzy:
Zhao, H.
Wang, Y.
Xu, Z.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/2011094.pdf
Data publikacji:
1999-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
78.60.-b
Opis:
Based on the calculation about intervalley scattering rates in ZnS, the intervalley transfer process in ZnS-type thin film electroluminescent devices is investigated through the Monte Carlo simulation. The transient time of intervalley transfer is about 0.2-0.3 ps, it coincides with that of electron average energy. Intervalley distribution shifts to high valleys as the electric field increased. The electron kinetic energy distributions in different valleys are also gained. We propose that high valleys could store energies, which could prolong the decay of the electron average energy as the field was removed. These results could be used as the basic data on the study of electroluminescent process and the citation of valley parameters in analytic models should be carefully considered.
Źródło:
Acta Physica Polonica A; 1999, 96, 3-4; 475-482
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of application of attapulgite on the structure and composition of self-dynamic membrane in bioreactors
Autorzy:
Duan, W.
Ling, C.
Fu, D.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/207004.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bioconversion
electrophoresis
polymerase chain reaction
porosity
bioreactor system
DGGE
extracellular polymeric substances
biokonwersja
elektroforeza
reakcja łańcuchowa polimerazy
porowatość
system bioreaktorów
zewnątrzkomórkowe substancje polimerowe
Opis:
The effect of application of attapulgite on the structure and composition of a dynamic membrane (DM) of a bioreactor was investigated by means of the electron microscopy, polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE). A significant increase of microbial floc size in the bioreactors upon attapulgite application was observed. The content of cake layer in the hybrid dynamic membrane (HDM) and in the dynamic membrane (DM) in the corresponding bioreactor systems were 44.73 g/m2 and 38.12 g/m2 respectively, while the contents of mineral – 6.09 g/m2 and 5.34 g/m2, respectively. Further, with addition of attapulgite, the concentration of extracellular polymeric substances (EPS) in the HDM bioreactor system decreased, whereas the content of suspended particulate matter increased. Self-DM has a porous structure with high porosity. Mineral sub-stance, including O, Ka, Ca, P, S, Cl, Mg and Si, are the main elements in DM, but the main elements content exhibited an increase trend in DM with attapulgite administration. These results showed a positive correlation between the quantity of bacterial populations and biological removal improvement, which indicated that application of attapulgite could optimize the structure of self-DM in bioreactors.
Źródło:
Environment Protection Engineering; 2016, 42, 2; 171-182
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The port service ecosystem research based on the Lotka-Volterra model
Autorzy:
Li, W.
Liu, W.
Xu, X.
Gao, Z.
Powiązania:
https://bibliotekanauki.pl/articles/259265.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
port service ecosystem
niche breadth
competitive co-evolution
mutually beneficial co-evolution
Opis:
Under the new normal of China’s economy, the competition among the port enterprises is not only the competition of the core competence of the port, the port industry chain or the port supply chain, but also the competition of the port service ecosystem. In this paper, the concept and characteristics of the port service ecosystem is discussed, a hierarchical model of the port service ecosystem is constructed. As an extended logistic model, Lotka-Volterra model is applied to study the competitive co-evolution and mutually beneficial co-evolution of enterprises in the port service ecosystem. This paper simulates the co-evolution of enterprises in the port service ecosystem by using MATLAB programming. The simulation results show that the breadth of the niche of the enterprises is changing with the change of the competition coefficient and the coefficient of mutual benefit in the port service ecosystem. Based on that, some proposals are put forward to ensure the healthy and orderly development of the port service ecosystem.
Źródło:
Polish Maritime Research; 2017, S 3; 86-94
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended Lie algebraic stability analysis for switched systems with continuous-time and discrete–time subsystems
Autorzy:
Zhai, G.
Xu, X.
Lin, H.
Liu, D.
Powiązania:
https://bibliotekanauki.pl/articles/929816.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
układ komutowany
funkcja Lapunowa
algebra Lie'go
stateczność wykładnicza
switched systems
common quadratic Lyapunov functions
Lie algebra
exponential stability
arbitrary switching
dwell time scheme
Opis:
We analyze stability for switched systems which are composed of both continuous-time and discrete-time subsystems. By considering a Lie algebra generated by all subsystem matrices, we show that if all subsystems are Hurwitz/Schur stable and this Lie algebra is solvable, then there is a common quadratic Lyapunov function for all subsystems and thus the switched system is exponentially stable under arbitrary switching. When not all subsystems are stable and the same Lie algebra is solvable, we show that there is a common quadratic Lyapunov-like function for all subsystems and the switched system is exponentially stable under a dwell time scheme. Two numerical examples are provided to demonstrate the result.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 4; 447-454
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł

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