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Tytuł:
Comparative investigation of SiC and Si power electronic devices operating at high switching frequency
Autorzy:
Zymmer, K.
Mazurek, P.
Powiązania:
https://bibliotekanauki.pl/articles/200057.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
semiconductor devices
silicon carbide
high frequency converters
Opis:
The paper presents results of measurements of the reverse recovery current and dynamic forward voltage of the silicon carbide (SiC) Schottky diodes operating at a 500 A/ěs current slope. These data were compared with the corresponding parameters determined for ultrafast silicon (Si) diodes. Results of power losses measurement in SiC Schottky diodes operating at switching frequency range of (10–200) kHz are presented and compared with corresponding data of ultrafast Si diodes. Also, results of power losses measurements in transistors of dc voltage switch are shown. Investigations were conducted with a SiC and the ultrafast Si freewheeling diode at the transistor switching frequency of 100 kHz. The results of measuring power losses dissipated in the dc converter with a SiC Schottky diode and the ultrafast silicon diode are also presented.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 555-559
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long term validation of high precision RTK positioning onboard a ferry vessel using the MGBAS in the Research Port of Rostock
Autorzy:
Ziebold, R.
Gewies, S.
Powiązania:
https://bibliotekanauki.pl/articles/116814.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
vessel's damage consequences
long term validation
high precision RTK positioning
Real Time Kinematic (RTK)
Maritime Ground Based Augmentation Service (MGBAS)
Port of Rostock
Global Positioning System (GPS)
Ultra High Frequency (UHF)
Opis:
In order to enable port operations, which require an accuracy of about 10cm, the German Aerospace Center (DLR) operates the Maritime Ground Based Augmentation Service (MGBAS) in the Research Port of Rostock. The MGBAS reference station provides GPS dual frequency code + phase correction data, which are continuously transmitted via an ultra-high frequency (UHF) modem. Up to now the validation of the MGBAS was rather limited. Either a second shore based station was used as an artificial user, or measurement campaigns on a vessel with duration of a few hours have been conducted. In order to overcome this, we have installed three separate dual frequency antennas and receivers and a UHF modem on the Stena Line ferry vessel Mecklenburg-Vorpommern which is plying between Rostock and Trelleborg. This paper concentrates on the analysis of the highly accurate phase based positioning with a Real Time Kinematic (RTK) algorithm, using correction data received by the UHF modem onboard the vessel. We analyzed the availability and accuracy of RTK fix solutions for several days, whenever the ferry vessel was inside the service area of the MGBAS.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2017, 11, 3; 433-440
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of methods for hourly electricity demand forecasting in the absence of data - a case study
Analiza porównawcza metod prognozowania godzinnego zapotrzebowania na energię elektryczną przy brakach w danych - studium przypadku
Autorzy:
Zawadzki, Jan
Powiązania:
https://bibliotekanauki.pl/articles/2194900.pdf
Data publikacji:
2023
Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Tematy:
forecasting
missing data
time series
high frequency
Opis:
Scope and purpose of work: This paper examines the impact of the number of gaps in data, the analytical form, and the model type selection criterion on the accuracy of interpolation and extrapolation forecasts for hourly data. Materials and methods: Forecasts were developed on the basis of predictors that are based on: classical time series forecasting models and regression time series forecasting models, hybrid time series forecasting models and hybrid regression forecasting models for uncleared series, and exponential smoothing models for cleared series of two or three types of seasonal fluctuations, with minimum estimates of errors in interpolation or extrapolation forecasts. Results: Adaptive and hybrid regression models have proved to have the most favorable predictive properties. Most hybrid time series models for systematic and non-systematic gaps and for both analytical forms are single models that generally describe fluctuations within a 24-hour cycle. Conclusions: The lowest estimators of prediction errors involving interpolation were obtained for exponential smoothing models, followed by hybrid regression models. A reverse sequence was obtained for extrapolative forecasting.
Źródło:
Economic and Regional Studies; 2023, 16, 1; 34-50
2083-3725
2451-182X
Pojawia się w:
Economic and Regional Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MODELE ADAPTACYJNE W PROGNOZOWANIU NA PODSTAWIE SZEREGÓW CZASOWYCH O WYSOKIEJ CZĘSTOTLIWOŚCI Z LUKAMI SYSTEMATYCZNYMI
ADAPTIVE MODELS IN FORECASTING OF HIGH-FREQUENCY TIMES SERIES WITH SYSTEMATIC GAPS
Autorzy:
Zawadzki, Jan
Powiązania:
https://bibliotekanauki.pl/articles/453186.pdf
Data publikacji:
2017
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
prognozowanie
dane o wysokiej częstotliwości
złożona sezonowość
wyrównywanie wykładnicze
luki systematyczne
forecasting
high frequency data
complex seasonality
exponential smoothing
systematic gaps
Opis:
W pracy przedstawione zostaną wyniki zastosowania modeli Browna, Holta i Holta-Wintersa w prognozowaniu zmiennej o bardzo wysokiej częstotliwości obserwowania w warunkach braku pełnej informacji na podstawie danych oczyszczonych z dwóch lub trzech rodzajów sezonowości. Rozpatrywany były dwa warianty luk systematycznych.
In the paper will be presented results of the application of Brown, Holt and Holt-Winters models in the forecasting of a very high frequency variable in condition of lack of full information, based on seasonal adjusted time series, from which two or three types of seasonal fluctuations were removed. Two variants of systematic gaps were considered.
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2017, 18, 2; 374-389
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis of the performance of genetic programming for realised volatility forecasting
Autorzy:
Yin, Z.
O’Sullivan, C.
Brabazon, A.
Powiązania:
https://bibliotekanauki.pl/articles/91765.pdf
Data publikacji:
2016
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
realised volatility
genetic programming
high frequency data
Opis:
Traditionally, the volatility of daily returns in financial markets is modeled autoregressively using a time-series of lagged information. These autoregressive models exploit stylised empirical properties of volatility such as strong persistence, mean reversion and asymmetric dependence on lagged returns. While these methods can produce good forecasts, the approach is in essence atheoretical as it provides no insight into the nature of the causal factors and how they affect volatility. Many plausible explanatory variables relating market conditions and volatility have been identified in various studies but despite the volume of research, we lack a clear theoretical framework that links these factors together. This setting of a theory-weak environment suggests a useful role for powerful model induction methodologies such as Genetic Programming (GP). This study forecasts one-day ahead realised volatility (RV) using a GP methodology that incorporates information on market conditions including trading volume, number of transactions, bid-ask spread, average trading duration (waiting time between trades) and implied volatility. The forecasting performance from the evolved GP models is found to be significantly better than those numbers of benchmark forecasting models drawn from the finance literature, namely, the heterogeneous autoregressive (HAR) model, the generalized autoregressive conditional heteroscedasticity (GARCH) model, and a stepwise linear regression model (SR). Given the practical importance of improved forecasting performance for realised volatility this result is of significance for practitioners in financial markets.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2016, 6, 3; 155-172
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of the power supply and control system for the hemodialysis machine
Rozwój układu zasilania i sterowania urządzenia do hemodializy
Autorzy:
Yaskiv, Volodymyr
Yaskiv, Anna
Powiązania:
https://bibliotekanauki.pl/articles/27315436.pdf
Data publikacji:
2023
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
hemodialysis
power supply and control system
rectangular hysteresis loop
high-frequency magnetic amplifier
hemodializa
układ zasilania i sterowania
prostokątna pętla histerezy
wzmacniacz magnetyczny wysokiej częstotliwości
Opis:
The article describes new approaches to creating an autonomous compact system with automatic control for hemodialysis. It is proposed to organize a closed circuit for cleaning the dialysis solution using an electrolytic regenerator as a function of the concentration of urea in it. The functional diagram of the created system is presented and described. To power the regenerator, ensure thermal stabilization of the solution, and power auxiliary electronic and electrical equipment, a multi-channel power supply and control system for the hemodialysis machine based on high-frequency magnetic amplifiers has been developed and researched. The advantages of power switches based on high-frequency magnetic amplifiers in comparison with transistor switches, including in the construction of controlled power sources, are given. The principle of operation of the voltage regulator on high-frequency magnetic amplifiers is described. Theoretical and experimental oscillograms are given. Photographs of the experimental unit as well as an industrial sample of the multi-channel power supply and control system of the hemodialysis machine are provided. Their main technical characteristics are given. Conclusions to the conducted work are formulated. Carrying out the regeneration of the dialysis solution significantly reduces its costs – 2 liters of solution, which is suitable for use for 6 months, is enough for the operation of the device. Existing hemodialysis machines are a stationary open system using a single-use dialysis solution at a rate of up to 35 l/h, which ties the machine to stationary clinical conditions. Introducing feedback on the concentration of urea in the dialysis solution allows you to automate the blood purification procedure, as well as automatically complete hemodialysis at the necessary time, and also eliminates the dependence of the device on the conditions of the hospital.
Do zasilania regeneratora, stabilizacji termicznej roztworu oraz zasilania pomocniczych urządzeń elektronicznych i elektrycznych opracowano i zbadano wielokanałowy układ zasilania i sterowania aparatu do hemodializy oparty na wzmacniaczach magnetycznych wysokiej częstotliwości. Przedstawiono zalety wyłączników mocy opartych na wzmacniaczach magnetycznych wysokiej częstotliwości w porównaniu z wyłącznikami tranzystorowymi, w tym w budowie sterowanych źródeł prądu. Opisano zasadę działania regulatora napięcia we wzmacniaczach magnetycznych wysokiej częstotliwości. Podano oscylogramy teoretyczne i eksperymentalne. Przedstawiono fotografie jednostki doświadczalnej oraz próbkę przemysłową wielokanałowego układu zasilania i sterowania aparatu do hemodializy. Podano ich główne parametry techniczne. Sformułowano wnioski z przeprowadzonej pracy. Przeprowadzenie regeneracji płynu do dializy znacząco obniża jego koszty – do pracy urządzenia wystarczają 2 litry płynu, który wystarcza na 6 miesięcy. Istniejące aparaty do hemodializy to stacjonarne systemy otwarte wykorzystujące roztwór do dializy jednorazowego użytku z szybkością do 35 l/h, co wiąże urządzenie ze stacjonarnymi warunkami klinicznymi. Wprowadzenie informacji zwrotnej o stężeniu mocznika w płynie dializacyjnym pozwala zautomatyzować procedurę oczyszczania krwi, a także automatycznie zakończyć hemodializę w wymaganym czasie, a także eliminuje zależność urządzenia od warunków panujących w szpitalu.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2023, 13, 3; 23--28
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A diode-pumped high-repetition-frequency passively Q-switched Nd:LaMgAl11O19 laser
Autorzy:
Xu, Yan
Gao, Ziye
Xia, Guangqiong
Wu, Zhengmao
Powiązania:
https://bibliotekanauki.pl/articles/1835801.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Nd:LaMgAl11O19 disordered crystal
Q-switched laser
high pulse repetition frequency
PRF
semiconductor saturable absorber mirror
SESAM
laser diode
LD
Opis:
High-repetition-frequency Q-switched laser is realized through adopting a Nd:LaMgAl11O19 (Nd:LMA) disordered crystal as the gain material, a laser diode lasing at 796 nm as the pumped source, and a semiconductor saturable absorber mirror (SESAM) as the Q-switched device. The out-put characteristics are analyzed under using different transmittance T plane mirrors as an output coupler. Without adopting SESAM, the laser is operating at a CW state, and a relatively high transmittance is helpful for achieving high output power, slope efficiency and light-to-light efficiency. ForT = 7.5% and an absorbed power of 6.17 W, the output power arrives at its maximum of 1160 mW,and the corresponding slope efficiency and light-to-light efficiency are 20.71% and 18.78%, respectively. After introducing SESAM into the cavity, the laser operates at a passively Q-switched state, and the largest slope efficiency is 13.14% under T = 5.0%. Adopting five different output couplers, with the increase of the absorbed power, the pulse repetition frequencies, the pulse energies and the peak powers will ascend while the pulse widths will decline. The observed narrowest pulse width, the maximum pulse repetition frequency, the highest pulse energy and peak power are 1.745 μs, 175.88 kHz, 3.21 μJ and 1.84 W, respectively.
Źródło:
Optica Applicata; 2020, 50, 3; 415-423
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyznaczanie właściwości uziemień metodami statycznymi, wysokoczęstotliwościowymi i udarowymi
Determination of earthing properties using static, high frequency and impulse methods
Autorzy:
Wołoszyk, M.
Wojtas, S.
Powiązania:
https://bibliotekanauki.pl/articles/157090.pdf
Data publikacji:
2008
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
uziemienie
metoda udarowa
rezystancja
metoda wysokoczęstotliwościowa
earthing
resistance
impulse method
high frequency method
Opis:
Podstawowym parametrem charakteryzującym skuteczność działania uziemienia jest jego rezystancja, a niekiedy rezystancja udarowa lub impedancja. Parametry te stosowane są często zamiennie chociaż wyznacza się je różnymi metodami i często mają one różne wartości liczbowe dla tego samego uziemienia. W artykule przedstawiono różne metody pomiaru tych parametrów oraz zaprezentowano wyniki badań porównawczych wykonanych przy użyciu metody statycznej, wysokoczęstotliwościowej oraz udarowej. Omówiono obszary zastosowań oraz ograniczenia omawianych metod, a także typowe błędy związane z interpretacją wyników i błędy w dobrze metody.
The basic parameter for evaluating the earthing is usually its resistance. Sometimes the earthing properties are described by means of its impulse resistance or impedance. These parameters are determined by different methods and they often have different numerical values for the same earthing. The paper presents different methods for measuring the earthing parameters mentioned above and the results of comparative investigations obtained from the static, high frequency and impulse procedures. The aplication areas and limitations of all the described measurement methods as well as typical mistakes are described. The main reasons for the mistakes are usually wrong interpretations of the obtained results and wrong choice of the measurement method.
Źródło:
Pomiary Automatyka Kontrola; 2008, R. 54, nr 12, 12; 836-838
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement and Analysis of Partial Discharge using an Ultra-High Frequency Sensor for Gas Insulated Structures
Autorzy:
Wang, G.
Kil, G.-S.
Powiązania:
https://bibliotekanauki.pl/articles/221519.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas insulated structures
partial discharge
ultra-high frequency sensor
conversion
Opis:
Although the gas insulated structures have a high degree of reliability, the unavoidable defects are primary reason of their failures. Partial discharge (PD) has been regarded as an effective indication for condition monitoring and diagnosis of gas insulated switchgears (GISs) to ensure their reliable and stable operation. Among various PD detection methods, the ultra-high frequency (UHF) technique has the advantages of on-line motoring and defect classification. In this paper, there are presented 7 types of artificial electrode systems fabricated for simulation of real insulation defects in gas insulated structures. A real-time measurement system was developed to acquire defect patterns in a form of phase-resolve partial discharge (PRPD) intensity graph, using a UHF sensor. Further, the discharge distribution and statistical characteristics were extracted for defect identification using a neural network algorithm. In addition, a conversion experiment was proposed by detecting the PD pulse simultaneously using a non-induction resistor and a UHF sensor. A relationship between the magnitude of UHF signal and the amplitude of apparent charge was established, which was used for evaluation of PD using the UHF sensor.
Źródło:
Metrology and Measurement Systems; 2017, 24, 3; 515-524
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of low and high frequency fatigue tests
Autorzy:
Vasko, A.
Belan, J.
Kucharikova, L.
Powiązania:
https://bibliotekanauki.pl/articles/111844.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
fatigue test
low frequency cyclic loading
high frequency cyclic loading
nodular cast iron
test zmęczeniowy
cykliczne obciążenie niskoczęstotliwościowe
cykliczne obciążenie o wysokiej częstotliwości
żeliwo sferoidalne
Opis:
The paper presents the results of low and high frequency fatigue tests carried out on nodular cast iron. The specimens of synthetic nodular cast irons from three different melts were studied in the high cycle fatigue region (from 105 to 108 cycles) using fatigue experimental equipments for low and high frequency cyclic loading. Low frequency fatigue tests were carried out at frequency f ≈ 120 Hz using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100; high frequency fatigue tests were carried out at frequency f ≈ 20 kHz using the ultrasonic fatigue testing device KAUP-ZU. Both fatigue tests were realised at sinusoidal cyclic push-pull loading (stress ratio R = –1) at ambient temperature (T = 20 ± 5 °C).
Źródło:
Production Engineering Archives; 2017, 17; 15-18
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The potential for real-time testing of high-frequency trading strategies through a developed tool during volatile market conditions
Autorzy:
Vaitonis, Mantas
Korovkinas, Konstantinas
Powiązania:
https://bibliotekanauki.pl/articles/30148245.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
high frequency trading
cryptocurrencies
algorithmic trading
multidimensional matrice
parallelization
simulation
Opis:
This study presents a method for testing high-frequency trading (HFT) for algorithms on GPUs using kernel parallelization, code vectorization, and multidimensional matrices. The research evaluates HFT strategies within algorithmic cryptocurrency trading in volatile market conditions, particularly during the COVID-19 pandemic. The study's objective is to provide an efficient and comprehensive approach to assessing the efficiency and profitability of HFT strategies. The results show that the method effectively evaluates the efficiency and profitability of HFT strategies, as demonstrated by the Sharp ratio of 2.29 and the Sortino ratio of 2.88. The authors suggest that further study on HFT testing methods could be conducted using a tool that directly connects to electronic marketplaces, enabling real-time receipt of high-frequency trading data and simulation of trade decisions. Finally, the study introduces a novel method for testing HFT algorithms on GPUs, offering promising results in assessing the efficiency and profitability of HFT strategies during volatile market conditions.
Źródło:
Applied Computer Science; 2023, 19, 2; 63-81
1895-3735
2353-6977
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antireflux surgery is required after endoscopic treatment for Barrett’s esophagus
Autorzy:
Tyselskyi, Volodymyr
Poylin, Vitaliy
Tkachuk, Olga
Kebkalo, Andrey
Powiązania:
https://bibliotekanauki.pl/articles/1391513.pdf
Data publikacji:
2021
Wydawca:
Index Copernicus International
Tematy:
antireflux operation
argonoplasmic coagulation
Barrett’s esophagus
gastroesophageal reflux disease
high-frequency welding of living tissues
Opis:
Introduction: Barrett’s esophagus is an acquired condition that develops as a result of transformation of normal stratified squamous epithelium in the lower part of the esophagus into columnar epithelium. Barrett’s esophagus is considered to be a complication of gastroesophageal reflux disease (GERD). Various endoscopic techniques have been shown to be successful in the treatment of this condition. However, long-term success in preventing further esophageal dysplasia is not clear. Biological welding consists in the application of controlled high-frequency current on living tissues and has been used to stop gastrointestinal bleeding, similarly to the APC technique which involves ablation of small intestinal metaplasia of the esophageal mucosa. Aim: The goal of this study was to evaluate the effectiveness of endoscopic techniques in the treatment of Barrett’s esophagus and verify the need for a subsequent surgical intervention in patients with GERD complicated by Barrett’s esophagus. Material and methods: Patients with Barrett’s esophagus C1-3M2-4 (Prague classification from 2004) and high dysplasia without nodules, as well as patients with confirmed GERD without hiatal hernia, were included in this study. Endoscopic treatment was performed with the use of argonoplasmic coagulation (APC) and high-frequency welding of living tissues (HFW). After the examination the patients were re-examined. Patients with recurrence of metaplasia and high DeMeester score (˃ 100) underwent antireflux surgery – crurography and Nissen fundoplication with creation of a soft and short cuff.Results: A total of 89 patients were included in the study, 81 of whom were reexamined after ablation of Barrett’s esophagus.In 12 patients, a recurrence of intestinal metaplasia resembling the small intestine was identified. Implementation of two-stage treatment was required for 9 patients – it involved a second procedure of ablation of the esophagus, followed by antireflux surgery. Surgical treatment was refused by 3 patients, who underwent only the second ablation procedure. All patients received drug therapy, consisting of prokinetics and proton pump inhibitors. Esophageal pH monitoring was repeated 3 months after surgery, showing normalization of the DeMeester score. As a result, the patients experienced no complaints such as heartburn, chest pain or dysphagia, which significantly improved their quality of life. Esophagogastroduodenoscopy and biopsy of the mucous membrane of the lower third of the esophagus were performed in accordance with the Seattle Protocol. After examining histological specimens, no regions of metaplasia were identified. Conclusion: Antireflux surgery is required as a part of the treatment for Barrett’s esophagus, which prevents further dysplasia and development of esophageal cancer.
Źródło:
Polish Journal of Surgery; 2021, 93, 5; 1-5
0032-373X
2299-2847
Pojawia się w:
Polish Journal of Surgery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the influence of power frequency electric field of pantograph on passengers’ health in high-speed EMU
Autorzy:
Tian, Rui
Zhang, Jia-Qi
Lu, Mai
Powiązania:
https://bibliotekanauki.pl/articles/24202736.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
induced current density
induced electric field intensity
high-speed EMU
pantograph
power frequency electric field
Opis:
In this work we discussed the safety of the electric field environment in the No. 3 carriage where the pantograph is located. DSA380 pantograph, CRH5 EMU carriage and passengers’ models were established to study the electric field exposure of passengers at different positions. The results showed that Emax in the carriage without passengers is 1.173 x 10 6 mV/m. Then we set the passengers’ positions according to the electric field distribution in the carriage without passengers and obtained that Emax in the carriage with passengers is 3.195 x 10 6 mV/m. It can be seen that the maximum induced electric field intensity of passengers at different positions appears on the soles of shoes, the maximum value is 3.028 x 105 mV/m, the maximum induced current density occurs at the ankle, its maximum value is 3.476 x 10 -5 A/m 2. It can be concluded that the maximum induced electric field intensity of passenger’s head appears in the cerebrospinal fluid area, with a maximum value of 202.817 mV/m, and the maximum induced electric field intensity of passenger’s head at the door is larger than that in the middle of the carriage. The maximum values of the induced electric field intensity in all tissues of passengers are much smaller than the basic limits of electromagnetic exposure to the public set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This study indicated that the pantograph has little influence on the electric field environment in the carriage under working state, and will not cause any health hazard to the passengers in this working frequency electric field environment.
Źródło:
Archives of Electrical Engineering; 2023, 72, 2; 483--501
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the topology of „Shore to Ship” systems - power electronic connection of ships with land
Autorzy:
Tarnapowicz, Dariusz
German-Galkin, Sergiei
Powiązania:
https://bibliotekanauki.pl/articles/27315926.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
system Shore to Ship
przetwornica częstotliwości
zasilacz wysokiego napięcia
Shore to Ship system
frequency inverter
high voltage power supply
Opis:
The possibility of building efficient and universal systems for the use of electricity land network by ships berthed in the port appeared along with the development of power electronic technologies. The need to connect ships to the land network is primarily related to ecological reasons. The choice of the appropriate topology by the investor (usually port authorities) is mainly connected with ensuring high quality of electricity provided to the ship and local conditions. The article reviews topologies of power electronic system (possible to use) for connection of ships with the land network - their disadvantages and advantages.
Źródło:
New Trends in Production Engineering; 2018, 1, 1; 325-333
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modele hierarchiczne w prognozowaniu zmiennych o wysokiej częstotliwości obserwowania w warunkach braku pełnej informacji
Hierarchical models in forecasting of the high-frequency variables in the conditions of lack of full information
Autorzy:
Szmuksta-Zawadzka, Maria
Zawadzki, Jan
Powiązania:
https://bibliotekanauki.pl/articles/425235.pdf
Data publikacji:
2014
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
high-frequency data
hierarchical models
incomplete time series
Opis:
The paper presents a procedure of application of regular hierarchical models in forecasting missing data in high-frequency time series with cyclical fluctuations. Annual, weekly and daily cycles of seasonal fluctuation have additive character. Separately regular hierarchical models have been built for even length cycles.Theoretical considerations are illustrated with an empirical example.
Źródło:
Econometrics. Ekonometria. Advances in Applied Data Analytics; 2014, 4(46); 72-84
1507-3866
Pojawia się w:
Econometrics. Ekonometria. Advances in Applied Data Analytics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 100

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