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Wyszukujesz frazę "Han, D." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Multi-grid model for crowd’s evacuation in ships based on cellular automata
Autorzy:
Chen, M.
Han, D.
Powiązania:
https://bibliotekanauki.pl/articles/963361.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
crowds’ evacuation in ships
multi-grid model
cellular automata model
finer lattice
interaction force
Opis:
In order to enhance the authenticity and accuracy simulation of passengers’ evacuation in ships, a new multi-grid model is proposed on the basis of cellular automata theory. By finer lattice the multi-grid model could enhance the continuity of passengers’ track and the precision of boundary’s qualification compared with traditional cellular automata model. Attraction, repulsion and friction are also quantized in the multi-grid model to present the impact of interaction force among pedestrians. Furthermore, crowd’s evacuation simulated by traditional cellular automata and multi-grid model in single exit room and typical cabin environment have been taken as examples to analyze crowd’s motion laws. It is found that the laws of passengers’ evacuation simulated by the two models are similar, and the simulation authenticity and accuracy is enhanced by the multi-grid model.
Źródło:
Polish Maritime Research; 2015, S 1; 75-81
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of Ionospheric Delay for SBAS Using Spherical Harmonics Functions
Autorzy:
Han, D.
Yun, H.
Kee, C.
Powiązania:
https://bibliotekanauki.pl/articles/116620.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Consequences of Delays
Ionospheric Delay
satellite based augmentation system (SBAS)
Opis:
In SBAS (satellite‐based augmentation system), it is important to estimate ionospheric delay accurately to guarantee userʹs accuracy and integrity. Grid based ionospheric models are generally used to estimate ionospheric delay for SBAS. In grid based model, SBAS broadcasts vertical ionospheric delays at the grid point, and users get their ionospheric delay by interpolating those values. Ionospheric model based on spherical harmonics function is another method to estimate ionospheric delay. This is a function based approach and spherical harmonics function is a 2‐D fourier series, containing the product of latitude dependent associated Legendre functions and the sum of the longitude dependent sine and cosine terms. Using ionospheric delay measurements, coefficients for each spherical harmonics functions are estimated. If these coefficients are known, user can reconstruct ionospheric delay. In this paper, we consider the spherical harmonics based model and propose a ionospheric delay estimation strategy for SBAS that can be used to mitigate ionospheric delay estimation error, especially in storm condition. First, coefficients are estimated under initial order and degree. Then residual errors for each measurement are modeled by higher order and degree terms, then coefficients for these terms are estimated. Because SBAS message capacity is limited, in normal condition, initial order terms are only used to estimate ionospheric delay. If ionospheric storm is detected and there is need to mitigate the error, higher order terms are also used and error can be decreased. To compare the accuracy of spherical harmonics based model with grid based model, some post‐processing test results are presented. Raw observation data is obtained from RINEX format and the root mean square(RMS) and max value of residual errors are presented.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2013, 7, 2; 205-209
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved resonant thermal converter based on micro-bridge resonator
Autorzy:
Dong, L.
Han, J.
Zhang, P.
Zhao, Z.
Cheng, B.
Han, D.
Powiązania:
https://bibliotekanauki.pl/articles/220878.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermoelectric transfer difference
micro-bridge resonator
thermal converter
bifilar heater
Opis:
This paper presents the design, fabrication and testing of an improved thin-film thermal converter based on an electro-thermally excited and piezo-resistively detected micro-bridge resonator. The resonant thermal converter comprises a bifilar heater and an opposing micro-bridge resonator. When the micro-bridge resonator absorbs the radiant heat from the heater, its axial strain changes, then its resonant frequency follows. Therefore the alternating voltage or current can be transferred to the equivalent DC quantity. A non-contact temperature sensing mechanism eliminates heat loss from thermopiles and reduces coupling capacitance between the temperature sensor and the heater compared with traditional thin-film thermal converters based on thermopiles. In addition, the quasi-digital output of the resonant thin-film thermal converter eliminates such problems as intensity fluctuations associated with analogue signals output by traditional thin-film thermal converters. Using the fast-reversed DC (FRDC) method, the thermoelectric transfer difference, which determines the frequency-independent part of the ac-dc transfer difference, is evaluated to be as low as 1.1 · 10-6. It indicates that the non-contact temperature sensing mechanism is a feasible method to develop a high-performance thermal converter.
Źródło:
Metrology and Measurement Systems; 2018, 25, 4; 715-725
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding the Oxide Dispersion Behavior of Yttria in Metal Matrix of MA956 Alloy through High-Energy Milling and Hot Press Sintering
Autorzy:
Swain, B.
Han, D.
Kim, G.-H.
Kong, M.-S.
Ahn, B.
Powiązania:
https://bibliotekanauki.pl/articles/351770.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ODS
mechanical alloying
high-energy milling
oxide particle distribution
Opis:
MA956 (Fe-Cr-Al) alloy powder was high-energy ball milled with various amount of yttria contents (1,2,3, and 4 wt.%) to fabricate an oxide dispersion strengthened alloy. The milled powders were then consolidated using hot press sintering at 1150°C. The surface morphology and crystal structure of MA956 powder during the high-energy milling depending on the yttria contents was investigated using particle size analysis, X-ray diffraction, and scanning electron microscopy. The microstructural analysis of sintered alloy was performed using transmission electron microscopy and energy dispersive spectroscopy to evaluate the dispersion behavior of yttrium oxide. The results showed that, as yttria contents increased, the oxide particles became finer and are uniformly distributed during the high-energy milling. However, after the sintering, the oxide particles were coarsened with more than 3 wt.% of yttria addition.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1377-1381
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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