Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "switching" wg kryterium: Temat


Tytuł:
Calendar Anomalies, Market Regimes, and the Adaptive Market Hypothesis in African Stock Markets
Autorzy:
A. Obalade, Adefemi
Muzindutsi, Paul-Francois
Powiązania:
https://bibliotekanauki.pl/articles/1810536.pdf
Data publikacji:
2020-01-30
Wydawca:
Akademia Leona Koźmińskiego w Warszawie
Tematy:
calendar effect
intra-month
AMH; African stock markets
Markov switching model
Opis:
Findings: We found that (i) all the markets except for the Johannesburg Stock Exchange (JSE) have a higher tendency to be in bearish state than bullish state, (ii) month-of-the-year and intra-month effects appear in one regime and disappear in another regime, and (iii) the behavior of calendar Methodology: We applied two-stage Markov switching models (MSMs) instead of the conventional single state regression model. The sample period includes the daily index return of Nigerian, South African, Mauritian, Moroccan, and Tunisian stock exchanges from January 1998 to February 2018. Purpose: This paper examines the changing behavior of two calendar anomalies in African stock returns – the month-of-the-year and the intra-month effects – and their implications for the adaptive market hypothesis (AMH). anomalies is affected by market conditions and conforms to AMH rather than the efficient market hypothesis (EMH). Practical Implications: We present that (i) calendar anomaly is a characteristic that changes under different regimes or market conditions in African stock markets, (ii) active investment management may yield profits for market participants, depending on the market conditions and the anomaly in question, and (iii) the right approach would be for investors to consider each market with its own peculiarity even when they are in the same continent. Originality/Value: The sensitivity of the month-of-the-year and the intra-month effects to market conditions has not been documented in African stock markets, especially with the use of regime-switching models.
Źródło:
Central European Management Journal; 2019, 27(4); 71-94
2658-0845
2658-2430
Pojawia się w:
Central European Management Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A variable structure observer for the control of robot manipulators
Autorzy:
Abdessameud, A.
Khelfi, M. F.
Powiązania:
https://bibliotekanauki.pl/articles/908406.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
obserwator
manipulator robotyczny
stateczność wykładnicza
system naprowadzający
variable structure observers
switching-type observers
rigid robot manipulators
exponential stability
tracking control
Opis:
This paper deals with the application of a variable structure observer developed for a class of nonlinear systems to solve the trajectory tracking problem for rigid robot manipulators. The analyzed approach to observer design proposes a simple design methodology for systems having completely observable linear parts and bounded nonlinearities and/or uncertainties. This observer is basically the conventional Luenberger observer with an additional switching term that is used to guarantee robustness against modeling errors and system uncertainties. To solve the tracking problem, we use a control law developed for robot manipulators in the full information case. The closed loop system is shown to be globally asymptotically stable based on Lyapunov arguments. Simulation results on a 3-DOF robot manipulator show the asymptotic convergence of the vectors of observation and tracking errors.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2006, 16, 2; 189-196
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Code-switching on Facebook among Jordanians
Autorzy:
AbuTayeh, Amal
Powiązania:
https://bibliotekanauki.pl/articles/2013175.pdf
Data publikacji:
2021
Wydawca:
Komisja Nauk Filologicznych Polskiej Akademii Nauk, Oddział we Wrocławiu
Tematy:
code-switching
Facebook
computer-mediated communication
Opis:
Over the past years, the Internet has become a tool of communication among different people in the world. Due to the spread of the Internet, many researchers have focused their attention on the study of language use through the Internet. Code-switching is one of the sociolinguistic phenomena that have been observed in Computer Mediated Communication (CMC). The present paper explores the sociolinguistic phenomenon of code-switching in computer mediated communication by Jordanians. The study highlighted several English words that have been utilized for code-switching through online interaction. Furthermore, it studied the participants’ views about the role of Facebook in mixing Arabic with English. The methodology used in this study was descriptive, involving both qualitative and quantitative methods. An online questionnaire was shared on Facebook pages and groups. The sample included 181 participants; in addition, 35 interviews took place at home with relatives, with neighbors and in shops. The results revealed several perspectives about code-switching. Some participants mentioned that Facebook has led them to code-switch by using the most frequently switched words, such as; comment, like, group, share. Nevertheless, other participants mentioned that they prefer to use Modern Standard Arabic (MSA) and avoid using any English words in online activities, which means that Facebook has no impact on their language. A higher percentage of participants agreed that Facebook plays a role in mixing Arabic with English.
Źródło:
Academic Journal of Modern Philology; 2021, 14; 45-54
2299-7164
2353-3218
Pojawia się w:
Academic Journal of Modern Philology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationship between the verbal fluency and academic achievement in second and third grade students: the effects of gender and parents’ educational level
Autorzy:
Aksamovic, Armina
Djordjevic, Mirjana
Malec, Daniel
Memisevic, Haris
Powiązania:
https://bibliotekanauki.pl/articles/2106162.pdf
Data publikacji:
2019-06-20
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
verbal fluency
academic success
clustering and switching
school-aged children
Opis:
Verbal fluency is an important skill related to academic success. Many studies have indicated a strong link between verbal fluency and cognitive processes. The exact nature and size of the relationship between verbal fluency and academic success has not been extensively explored. Thus, the goal of the present study was to examine the relationship between verbal fluency, including its components clustering and switching, with academic success in a sample of second and third grade elementary school students. In addition to this, we examined the effects of gender and the parents’ level of education on verbal fluency. The sample for this study consisted of 61 second and third grade students (39 boys and 22 girls) attending two regular schools in the Mostar region, Bosnia and Herzegovina. Children were given tests of both semantic fluency and phonetic fluency. Teachers’ ratings were used as a measure of the children’s academic success. The results of this study indicated the strong link between verbal fluency and academic success. Components of verbal fluency, clustering and switching had a small effect on academic achievement. There was no effect of gender on verbal fluency and academic success. On the other hand, the parents’ level of education had a strong effect on both, verbal fluency and academic success. Verbal fluency, defined as the total number of words retrieved, is strongly related to academic success. Clustering and switching, as two components of verbal fluency, have a limited value in predicting academic achievement. However, the parents’ educational level is strongly related to academic success.
Źródło:
Acta Neuropsychologica; 2019, 17(2); 139-150
1730-7503
2084-4298
Pojawia się w:
Acta Neuropsychologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance evaluation of ZVS/ZCS high efficiency AC/DC converter for high power applications
Autorzy:
Ali, A.
Chuanwen, J.
Khan, M. M.
Habib, S.
Ali, Y.
Powiązania:
https://bibliotekanauki.pl/articles/200472.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
switching losses
zero current switching
zero voltage switching
power quality
reverse recovery loss
Opis:
The increased power density, reduced switching losses with minimum electromagnetic interference (EMI), and high efficiency are essential requirements of power converters. To achieve these characteristics, soft power converters employing soft switching techniques are indispensable. In this paper, a ZCS/ZVS PWM AC/DC converter topology has been emphasized, which finds applications in high power systems such as automobile battery charging and renewable energy systems. This converter scheme maintains zero current and zero voltage switching conditions at turn on and turn off moments of semiconductor switches, respectively and soft operation of rectifier diodes that lead to negligible switching and diode reverse recovery losses. Moreover, it improves power quality and presents high input power factor, low total harmonic distortion of the input current (THDI ) and improved efficiency. The validity of theoretical analysis of the proposed converter has been carried out experimentally on a 10 kW laboratory prototype. Experimental results prove that the soft switching operation of the semiconductor switches and diodes is maintained at 98.6% rated load efficiency. In addition, the performance evaluation has been performed by comparative analysis of the proposed converter with some prior art high power AC/DC converters. Efficiencies of the proposed and prior art high power topologies have been determined for different load conditions. The highest efficiency, power factor and lower THDI of the proposed converter topology complies with international standards.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 4; 793-807
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Overview of Mobility Management Mechanisms and the Related Challenges in 5G Networks and Beyond
Autorzy:
Alkalsh, Mustafa Mohammed Hasan
Powiązania:
https://bibliotekanauki.pl/articles/24200735.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
B5G
beam switching
handover
HetNet
mobility management
Opis:
Ensuring a seamless connection with various types of mobile user equipment (UE) items is one of the more significant challenges facing different generations of wireless systems. However, enabling the high-band spectrum – such as the millimeter wave (mmWave) band – is also one of the important factors of 5G networks, as it enables them to deal with increasing demand and ensures high coverage. Therefore, the deployment of new (small) cells with a short range and operating within the mmWave band is required in order to assist the macro cells which are responsible for operating long-range radio connections. The deployment of small cells results in a new network structure, known as heterogeneous networks (HetNets). As a result, the number of passthrough cells using the handover (HO) process will be dramatically increased. Mobility management (MM) in such a massive network will become crucial, especially when it comes to mobile users traveling at very high speeds. Current MM solutions will be ineffective, as they will not be able to provide the required reliability, flexibility, and scalability.Thus, smart algorithms and techniques are required in future networks. Also, machine learning (ML) techniques are perfectly capable of supporting the latest 5G technologies that are expected to deliver high data rates to upcoming use cases and services, such as massive machine type communications (mMTC), enhanced mobile broadband (eMBB), and ultra-reliable low latency communications (uRLLC). This paper aims to review the MM approaches used in 5G HetNets and describes the deployment of AI mechanisms and techniques in ″connected mode″ MM schemes. Furthermore, this paper addresses the related challenges and suggests potential solutions for 5G networks and beyond.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 2; 53--62
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Development of Biodegradable 3D Printed RDRA for Polarization Reconfigurability
Autorzy:
Apparao, Maganti
Karunakaran, Godi
Powiązania:
https://bibliotekanauki.pl/articles/2200726.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
polarization switching
circular polarization
linear polarization
dielectric resonator antennas
Opis:
In this article, a 3D printed rectangular dielectric resonator antenna which is capable of polarization reconfiguration has been designed. Dielectric resonator is composed of environment friendly and biodegradable material, which is Polylactic Acid. In the proposed model, the polarization can be switch from a linear to a circular by changing the state of a switch, electonically. The antenna switch between two different polarizations: Linear polarization during OFF STATE and Lefthand circular polarization during ON STATE. The proposed 3D printed dielectric resonator antenna is designed to operate in Cband of microwave spectrum, with a broad effective bandwidth (overlapped impedance bandwidths of both states) of 14.542% with centre frequency at 5.845GHz and peak gain 5.5dBi. Further, validated simulated results with experiment and both results are in good agreement.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 1; 69--74
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
What is Right and What is Wrong in the Environmental Governance Model? Environmental Regulations for Improving Environmental Sustainability Ratings
Co jest dobre, a co złe w modelu zarządzania środowiskiem? Analiza przepisów środowiskowych dla poprawy jakości zrównoważenia środowiskowego
Autorzy:
Ardiwinata, Jajat S.
Zaman, Khalid
Nassani, Abdelmohsen A.
Haffar, Mohamed
Pasani, Chairil Faif
Sriyanto, Sriyanto
Powiązania:
https://bibliotekanauki.pl/articles/2073439.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Komitet Człowiek i Środowisko PAN
Tematy:
environmental sustainability rating
environmental governance indicators
environmental regulations
government effectiveness
switching regression
klasyfikacja zrównoważoności środowiskowej
wskaźniki zarządzania środowiskowego
regulacje środowiskowe
skuteczność rządu
Opis:
The improper allocation of economic and environmental resources damages the United Nations sustainable development Agenda, which remains a challenge for policymakers to stop the rot through efficient governance mechanisms. The study designed an efficient environmental governance framework by extending the different governance factors linked to the environmental sustainability ratings in the cross-section of 67 countries. The results of the two-regime based estimator show that environmental corruption (regime-1), environmental politics (regime-2), and environmental laws (regime-2) negatively correlated with the environmental sustainability rating, whereas environmental democracy (regime-1 & 2) positively correlated with the environmental sustainability agenda across countries. The government effectiveness and the country’s per capita income both escalates environmental sustainability ratings. The results align with the Demopolis theory, the effective regulatory theory, and the theory of law and politics. The causality estimates show that environmental corruption and government effectiveness causes environmental politics and economic growth. In contrast, environmental democracy and environmental regulations cause a country’s per capita income. The bidirectional causality is found between environmental regulations and environmental corruption on the one hand, while environmental regulations and environmental politics Granger cause each other on the other hand. The results show the importance of environmental regulations in managing ecological corruption and politics across countries. The variance decomposition analysis suggested that environmental politics likely influenced the environmental sustainability agenda, followed by government effectiveness and environmental democracy for the next ten years. The study emphasized the need to design an efficient environmental governance framework that minimizes environmental corruption and enables them to move towards environmental democracy, stringent environmental laws, and regulations. Government effectiveness would mainly be linked to reducing corruption and political instability to achieve clean, green and sustainable development.
Niewłaściwa alokacja zasobów gospodarczych i środowiskowych szkodzi Agendzie ONZ na rzecz zrównoważonego rozwoju, która pozostaje wyzwaniem dla decydentów, aby powstrzymać negatywne trendy za pomocą skutecznych mechanizmów zarządzania. W ramach tego studium opracowano efektywne ramy zarządzania środowiskiem poprzez rozszerzenie zakresu różnych czynników zarządzania związanych z ocenami poziomu zrównoważenia środowiskowego wśród 67 krajów. Wyniki pokazują, że korupcja środowiskowa (system-1), polityka środowiskowa (system-2) i prawo środowiskowe (system-2) ujemnie korelowały z oceną zrównoważenia środowiskowego, podczas gdy demokracja środowiskowa (systemy-1 & 2) pozytywnie skorelowane są z Agendą zrównoważonego rozwoju środowiska w różnych krajach. Zarówno skuteczność rządu, jak i dochód kraju na mieszkańca podnoszą oceny zrównoważenia środowiskowego. Wyniki są zgodne z teorią Demopolis, efektywną teorią regulacji oraz teorią prawa i polityki. Szacunki przyczynowości pokazują, że korupcja środowiskowa i skuteczność rządu wpływają na politykę środowiskową i wzrost gospodarczy. W przeciwieństwie do tego, demokracja środowiskowa i regulacje środowiskowe powodują wzrost dochodu na mieszkańca. Dwukierunkowy związek przyczynowy występuje między regulacjami środowiskowymi a korupcją środowiskową z jednej strony, podczas gdy regulacje środowiskowe i polityka środowiskowa Granger są ze sobą bezpośrednio związane. Wyniki pokazują znaczenie przepisów środowiskowych w zarządzaniu korupcją ekologiczną i polityką w różnych krajach. Analiza rozkładu wariancji sugeruje, że polityka środowiskowa prawdopodobnie wpłynęła na program zrównoważonego rozwoju środowiska, a następnie skuteczność rządu i demokrację środowiskową przez następne dziesięć lat. W badaniu podkreślono potrzebę zaprojektowania skutecznych ram zarządzania środowiskiem, które zminimalizują korupcję środowiskową i umożliwią dążenie do demokracji środowiskowej, rygorystycznych przepisów i regulacji dotyczących ochrony środowiska. Skuteczność rządu byłaby powiązana głównie z ograniczaniem korupcji i niestabilności politycznej w celu osiągnięcia czystego, zielonego i zrównoważonego rozwoju.
Źródło:
Problemy Ekorozwoju; 2022, 17, 1; 123--139
1895-6912
Pojawia się w:
Problemy Ekorozwoju
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CHB inverter with DC-link capacitor balancing and total harmonic minimization
Autorzy:
Armi, F.
Manai, L.
Besbes, M.
Powiązania:
https://bibliotekanauki.pl/articles/141332.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CHB inverter
capacitor voltage balancing
switching angles
Newton Raphson
algorithm
SHE
THD
Opis:
A cascaded H-bridge (CHB) multilevel inverter generally requires several DC sources. An alternative option is to replace the separate DC source feeding an H-bridge cell with a capacitor, while maintaining the other H-bridge cell with a real DC voltage source. In this paper a 7-level cascaded H-bridge inverter with a single DC-source is presented. This paper focuses mainly to achieve effective capacitor voltage balancing and selective harmonic elimination (SHE) based on the Newton Raphson algorithm (N–R). It shows hope to reduce the voltage ripple of the capacitors, which leads to higher power conversion efficiency with equal power distribution, reduces the initial cost, and complexity hence it is apt for industrial applications. Simulation results support the proposed control technique.
Źródło:
Archives of Electrical Engineering; 2018, 67, 1; 81-93
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The selected problems of controllability of discrete-time switched linear systems with constrained switching rule
Autorzy:
Babiarz, A.
Czornik, A.
Klamka, J.
Niezabitowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200554.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
controllability
switched systems
discrete-time linear systems
switching rule
hybrid systems
sterowalność
systemy przełącznicowe
systemy liniowe
zasada przełączania
systemy hybrydowe
Opis:
In this paper the controllability problem for discrete-time linear switched systems is considered. The main goal is to find a control signal that steers any initial state to a given final state independently of the switching signal. In the paper, it is assumed that there are some constraints posed on the switching signal. Moreover, we present a necessary and sufficient conditions of some kinds of controllability. Three types of controllability, namely: from zero initial state to any final state, from any initial state to zero final state and from any initial state to any final state are considered. Finally, three illustrative examples are shown.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 3; 657-666
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of an Adaptive Switching Point for LTE TDD by Dynamic System-Level Simulations
Autorzy:
Backfrieder, C.
Ostermayer, G.
Powiązania:
https://bibliotekanauki.pl/articles/226992.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mobile network simulation
system levels
long term evolution
time division duplex
variable switching point
Opis:
This paper introduces an LTE system level simulator and presents investigations of scenarios with differently balanced traffic emergence between uplink and downlink as well as inhomogeneous distribution of link direction asymmetry. In the TDD mode of LTE, duplexing is implemented via sharing the time domain between uplink and downlink users. This is done by different switching configurations, which offer varying capacity distributions between downlink and uplink, from a downlink-heavy configuration with 90 percent of the capacity in downlink direction to uplink heavy configurations with 60 percent uplink. We utilize the available capacity perfectly by adjusting the link configuration appropriately to traffic emergence. Performance gains when selecting a configuration appropriate to the arising traffic compared to usage of a static configuration with equally distributed capacity are investigated. In case of different configurations, additional interference can occur in neighbored cells due to distinct communication direction at the same time. We clarify the differences between these scenarios and quantify the gains and losses when the switching point between uplink and downlink is variable.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 2; 171-178
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variational formalism applied to control of autonomous switching systems
Autorzy:
Bagdouri, M. E.
Cebron, B.
Sechilariu, M.
Burger, J.
Powiązania:
https://bibliotekanauki.pl/articles/970461.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
teoria sterowania
system komutacyjny
rachunek wariacyjny
control theory
switching systems
variational calculation
Opis:
The formalism of the calculus of variations is applied to determine an optimal control of a class of Hybrid Dynamical Systems. This class consists of autonomous switching systems where jumps of the state are taken into account. It is shown that model switching involves discontinuities in the adjoint state of the system. The expression of the gradient of the cost function, with respect to the control, allows for the calculation of an optimal control by implementing a descent method. Au illustrative linear quadratic example is given, which allows to conclude that, the method can be easily implemented.
Źródło:
Control and Cybernetics; 2004, 33, 4; 535-549
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photo-enhanced conduction in inhomogeneous thin film space charge limited conducting systems
Fotowzmocnione przewodnictwo w niejednorodnych układach cienkowarstwowych zdominowanych przez prądy ograniczone ładunkiem przestrzennym
Autorzy:
Bąk, G. W.
Powiązania:
https://bibliotekanauki.pl/articles/296597.pdf
Data publikacji:
2016
Wydawca:
Politechnika Łódzka. Wydawnictwo Politechniki Łódzkiej
Tematy:
space charge limited currents
optical switching
prądy ograniczone ładunkiem przestrzennym
komutacja optyczna
Opis:
Photo-enhancement of space-charge limited currents in deliberately modified thin-film structures is studied using numerical methods. The obtained results suggest that it should be possible to obtain optically induced increase in current density of the order of 107 in modified thin film structures as a result of deliberate modification of trap density at the emitter consisting in formation of high density of traps at the emitter.
Badane są metodami numerycznymi prądy ograniczone ładunkiem przestrzennym w świadomie modyfikowanych strukturach cienkowarstwowych. Otrzymane wyniki sugerują, że powinno być możliwe uzyskanie optycznie indukowanego wzrostu gęstości prądu rzędu 107 w układach z modyfikacją koncentracji pułapek przy emiterze, polegającą na wytworzeniu cienkiej warstwy o dużej koncentracji pułapek.
Źródło:
Scientific Bulletin. Physics / Technical University of Łódź; 2016, 37; 11-20
1505-1013
2449-982X
Pojawia się w:
Scientific Bulletin. Physics / Technical University of Łódź
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stabilization of autonomous linear time invariant fractional order derivative switched systems with different derivative in subsystems
Autorzy:
Balochian, S.
Powiązania:
https://bibliotekanauki.pl/articles/200478.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear time invariant fractional order derivative
switching systems
linear matrix inequality
LMI
Opis:
In this paper, the stabilization problem of a autonomous linear time invariant fractional order (LTI-FO) switched system with different derivative order in subsystems is outlined. First, necessary and sufficient condition for stability of an LTI-FO switched system with different derivative order in subsystems based on the convex analysis and linear matrix inequality (LMI) for two subsystems is presented and proved. Also, sufficient condition for stability of an LTI-FO switched system with different derivative order in subsystems for more than two subsystems is proved. Then a sliding sector is designed for each subsystem of the LTI-FO switched system. Finally, a switching control law is designed to switch the LTI-FO switched system among subsystems to ensure the decrease of the norm of the switched system. Simulation results are given to show the effectiveness of the proposed variable structure controller.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 3; 495-503
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Switching and lightning overvoltages and the required withstand voltage betweeen the open contacts of 245 KV circuit breakers
Przepięcia łączeniowe i piorunowe a wymagany poziom wytrzymałości otwartych styków wyłączników 245 KV
Autorzy:
Bandel, J.
Hejduk, A.
Dzierżyński, A.
Korycki, P.
Sibilski, H.
Powiązania:
https://bibliotekanauki.pl/articles/159303.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
high voltage circuit breakers
switching inductive and capacitive currents
switching and atmospheric overvoltage
lightning arresters
wyłączniki najwyższych napięć
łączenie prądów indukcyjnych i pojemnościowych
przepięcia łączeniowe i atmosferyczne
ogranicznik napięcia
Opis:
Przedstawiono sposób oceny wartości przepięć generowanych w sieci pomiędzy otwartymi stykami wyłącznika podczas operacji łączeniowych i wyładowań piorunowych. Wartości przepięć porównano z wartościami napięć probierczych wyłączników. Zaproponowano sposób doboru ograniczników napięcia. Wyłączanie prądów zwarciowych może powodować osłabienie izolacji komory wyłącznika zmniejszając jego wytrzymałość elektryczną i trwałość łączeniową. W energetyce zgłaszano przypadki zapłonów łuku na otwartych stykach wyłączników, tego rodzaju awarie mogą być bardzo groźne w skutkach. Problem ten dotyczy przede wszystkim wyłączników jednoprzerwowych, w których naprężenia elektryczne izolacji przerwy pomiędzy stykowej wyłącznika są bardzo duże. Z tego powodu pojawiają się postulaty zwiększenia liczby łączeń podczas badań typu wyłącznika, jakie należy wykonywać bez wymiany jakichkolwiek części komory wyłącznika, czy też napędu.
This paper deals with the surges generated in the network during switching operations and lightning surges. The level of both kinds of surge was compared with the required dielectric strength between the open contacts of 245 kV circuit breakers. Overvoltages greater than the electrical withstand voltage of the circuit breaker can cause arc ignition between the circuit breaker’s open contacts and power engineering service s have reported such cases. The results of such failures can be very serious. This is a problem especially for single-break circuit breakers, in which the stresses on the electrical insulation between the open contacts of the breaker are very high. A method for selecting lightning arresters to lower the overvoltages is proposed. The switching of short-circuit currents by a circuit breaker may cause a weakening of the circuit breaker chamber’s insulation and reduce its electrical withstand and durability.
Źródło:
Prace Instytutu Elektrotechniki; 2016, 274; 43-60
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies