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Wyszukujesz frazę "Jiang, Y." wg kryterium: Autor


Tytuł:
A Novel Multi-Exponential Function-based Companding Technique for Uniform Signal Compression over Channels with Limited Dynamic Range
Autorzy:
Moazzeni, T.
Selvaraj, H.
Jiang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/226887.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
companding
multi-exponential function
Mu-law
quantization
uniform signal compression
Opis:
Companding, as a variant of audio level compression, can help reduce the dynamic range of an audio signal. In analog (digital) systems, this can increase the signal-to-noise ratio (signal to quantization noise ratio) achieved during transmission. The µ-law algorithm that is primarily used in the digital telecommunication systems of North America and Japan, adapts a companding scheme that can expand small signals and compress large signals especially at the presence of high peak signals. In this paper, we present a novel multi-exponential companding function that can achieve more uniform compression on both large and small signals so that the relative signal strength over the time is preserved. That is, although larger signals may get considerably compressed, unlike µ-law algorithm, it is guaranteed that these signals after companding will definitely not be smaller than expanded signals that were originally small. Performance of the proposed algorithm is compared with µ-law using real audio signal, and results show that the proposed companding algorithm can achieve much smaller quantization errors with a modest increase in computation time.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 2; 125-128
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Objective Optimization of Acoustical Properties of PU-Bamboo-Chips Foam Composites
Autorzy:
Jiang, Y.
Chen, S.
Wang, D.
Chen, J.
Powiązania:
https://bibliotekanauki.pl/articles/177709.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vehicle sound package
sound absorption coefficient
transmission loss
Taguchi method
Opis:
In this study, an effective optimization approach was proposed to improve acoustical behaviors of PU foams. The important parameters of PU foams: content of water, silicone oil and catalyst A1 were chosen and their effects on sound absorption coefficient and transmission loss of PU foams were studied by using Taguchi methods. In addition, bamboo chips were incorporated into PU foams as fillers to improve the acoustical properties of PU foams. Four controlled factors: the content of water, silicone oil, catalyst A1 and bamboo chips with three levels for each factor were chosen and Taguchi method based on orthogonal array L9 (34) was employed to conduct the experiments. Based on the results of Taguchi’s orthogonal array L9 (34), signal-to noise (S/N) analysis was used and developed to determine an optimal formulation of PU-bamboo-chips foam composites.
Źródło:
Archives of Acoustics; 2017, 42, 4; 707-714
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Models for Distribution of the Envelope and Phase of Linearly Modulated Signals in AWGN Channel
Autorzy:
Moazzeni, T
Jiang, Y.
Selvaraj, H.
Chen, T.
Powiązania:
https://bibliotekanauki.pl/articles/226459.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital modulation
linear modulation
probability density function
phase
AWGN
Opis:
In this paper, analytical expressions for the distribution of the envelope and phase of linearly modulated signals such as BPSK, M-PSK, and M-QAM in AWGN are presented. We perform numerical simulations for different orders of signal constellations. The results show that the proposed theoretical models are in excellent agreement with the estimated distributions from various numerical experiments.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 1; 79-82
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a New Approach to SNR Estimation of BPSK Signals
Autorzy:
Moazzeni, T.
Amei, A.
Ma, J.
Jiang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/227148.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital communication
statistical analysis
AWGN channels
Opis:
Signal-to-noise ratio (SNR) information is required in many communication receivers and their proper operation is, to a large extent, related to the SNR estimation techniques they employ. Most of the available SNR estimators are based on approaches that either require large observation length or suffer from high computation complexity. In this paper, we propose a low complexity, yet accurate SNR estimation technique that is sufficient to yield meaningful estimation for short data records. It is shown that our estimator is fairly close to the (CRLB) for high SNR values. Numerical results also confirm that, in terms of convergence speed, the proposed technique outperforms the popular moment based method, M2M4.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 3; 273-278
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new simulation-optimization approach for the circulation facilities design at urban rail transit station
Autorzy:
Khattak, A.
Jiang, Y.
Zhu, J.
Hu, L.
Powiązania:
https://bibliotekanauki.pl/articles/223467.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
urban rail transit station
facilities design
genetic algorithm
simulation optimisation
stacja transportu miejskiego
projektowanie obiektów
algorytm genetyczny
symulacja optymalizacji
Opis:
Width design of the urban rail transit stations circulation facilities is a vital issue. The existing width design approach failed in fully considering the essential factors such as fluctuation in passengers’ arrival process, fluctuation and state-dependence in passengers walking speed and the blocking when passengers’ demand exceeds the capacity of facilities. For this purpose, a PH-based simulation-optimization approach is proposed that fully considers the fluctuation, the state-dependence, Level of Service (LOS) and blocking effect. This novel approach provides automatic reconfiguration of the widths of circulation facilities by a concurrent implementation of a PH-based Discrete-Event Simulation (DES) model and the Genetic Algorithm (GA). The proposed PH-based simulation-optimization approach and the existing design approaches based on the exponential and deterministic models are applied to design the widths of circulation facilities. The results reveal that the circulation facilities designed by the proposed approach have larger widths. Similarly, increase in the SCV of arrival interval results in increasing the widths designed by the proposed approach increase while the widths of the other two approaches stay the same. The width designed of the proposed approach increase at faster rate than that of the other two approach when the passengers’ arrival rate increases.
Źródło:
Archives of Transport; 2017, 43, 3; 69-90
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sound Absorption Behavior of Polyurethane Foam Composites with Different Ethylene Propylene Diene Monomer Particles
Autorzy:
Zhu, W.
Chen, S.
Wang, Y.
Zhu, T.
Jiang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/178030.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
polyurethane foam composites
EPDM
Ethylene Propylene Diene Monomer
contents of EPDM
hardness of EPDM
sound absorption coefficient
Opis:
Considering the environmental pollution caused by waste rubber, some measures should be taken to improve the utilization rate of waste rubber. In this study, the effect of Ethylene Propylene Diene Monomer (EPDM) particles in the polyurethane (PU) foams on sound absorption behavior is investigated for improving sound environment within vehicles and reducing the environment pollution. EPDM particles of different contents and hardness are used as fillers for producing foams with different pore morphologies and sound absorption properties. The results show that adding EPDM to foam would produce smaller pores, higher density and bigger air-flow resistivity. Simultaneously, there are better sound absorption properties of the PU foam composites in the medium frequency region, and the better value can be obtained at the lower frequency with the content of EPDM increasing. The hardness of EPDM also shows better influence on sound absorption properties, especially in the medium frequency region. It means the foam pore morphologies have influence on sound absorption properties.
Źródło:
Archives of Acoustics; 2018, 43, 3; 403-411
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Motion prediction of catamaran with a semisubmersible bow in wave
Autorzy:
Sun, H.
Jing, F.
Jiang, Y.
Zou, J.
Zhuang, J.
Ma, W.
Powiązania:
https://bibliotekanauki.pl/articles/258596.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
SSB catamaran
model test
overset grid
motion region
motion response
Opis:
Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB) demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a shortterm irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion.
Źródło:
Polish Maritime Research; 2016, 1; 37-44
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remote pipeline pumping transportation of cemented tailings backfill slurry
Przetłaczanie na znaczne odległości zawiesiny zawierającej odpady poflotacyjne oraz cement rurociągami z wykorzystaniem pomp
Autorzy:
Xiao, S.
Liu, Z.
Jiang, Y.
Li, C.
Sun, C.
Su, L.
Powiązania:
https://bibliotekanauki.pl/articles/219530.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
opory przepływu
przetłaczanie
eksperyment z wykorzystaniem linii obiegowej rurociągu
właściwości reologiczne
CFD (Computational Fluid Dynamics)
strong resistance
pipe pumping
pumping looping pipe experiment
rheological characteristic
CFD
Opis:
For most precious metal mines, cemented tailings backfill slurry (CTBS) with different cement-sand ratio and solid concentration are transported into the gobs to keep the stability of the stope and mitigate environmental pollution by mine tailing. However, transporting several kinds of CTBS through the same pipeline will increase the risk of pipe plugging. Therefore, the joint impacts of cement-sand ratio and solid concentration on the rheological characteristics of CTBS need a more in-depth study. Based on the experiments of physical and mechanical parameters of fresh slurry, the loss of pumping pressure while transporting CTBS with different cement-sand ratio, flux and solid mass concentration were measured using pumping looping pipe experiments to investigate the joint impacts of cement-sand ratio and solid concentration on the rheological characteristics of CTBS. Meanwhile, the effect of different stopped pumping time on blockage accident was revealed and discussed by the restarting pumping experiments. Furthermore, Fluent software was applied to calculate the pressure loss and velocity distribution in the pipeline to further analysis experimental results. The overall trends of the simulation results were good agreement with the experiment results. Then, the numerical model of the pipeline in the Sanshandao gold mine was conducted to simulate the characteristics of CTBS pipeline transportation. The results show that the pumping pressure of the delivery pump can meet the transportation requirements when there is no blockage accident. This can provide a theoretical method for the parameters optimizing in the pipeline transportation system.
W większości kopalń metali szlachetnych zawiesina zawierająca odpady poflotacyjne wraz z cementem w różnych proporcjach cementu i piasku oraz o różnym stężeniu części stałych transportowana jest do wyrobisk i zrobów, gdzie wykorzystywana jest następnie do stabilizacji w rejonie przodka, ponadto w ten sposób ogranicza się zanieczyszczenie środowiska odpadami poflotacyjnymi. Jednakże przetłaczanie różnych rodzajów zawiesin w tym samym układzie rurociągu zwiększa ryzyko zaczopowania rur. Zbadanie wpływu proporcji cementu do piasku w zawiesinie oraz stężenia części stałych na charakterystykę reologiczną zawiesiny wydaje się kwestią kluczową. W oparciu o badania eksperymentalne fizycznych i mechanicznych parametrów świeżej zawiesiny, dokonano pomiarów spadku ciśnienia pompowania w trakcie przetłaczania zawiesin o zawartości cementu i pisaku w różnych proporcjach, dla różnych natężeń przepływu i stężeń części stałych w eksperymentach z wykorzystaniem linii obiegowej rurociągu. Celem eksperymentu było określenie łącznego wpływu proporcji cementu do piasku oraz stężenia części stałych na właściwości reologiczne zawiesiny. Ponadto, przeanalizowano w jaki sposób długość przerw w procesie przetłaczania wpływa na zwiększenie ryzyka zatkania rur i przeprowadzono eksperymenty polegające na wznowieniu pracy pomp. Analizę wyników eksperymentów uzupełniono poprzez zastosowanie oprogramowania Fluent do obliczenia spadku ciśnienia w rurociągu oraz rozkładu prędkości. Wykazano, że wyniki symulacji pozostawały w dużej zgodności z wynikami eksperymentów. W kolejnym kroku opracowano model numeryczny rurociągu eksploatowanego w kopalni złota Sanshandao dla potrzeb symulacji procesu przetłaczania zawiesiny. Uzyskane wyniki wskazują, że ciśnienie tłoczenia w pompie jest na wymaganym poziomie gdy nie występuje zablokowanie przepływu w rurze, i wykorzystane być mogą jako uzupełnienie teoretycznych metod optymalizacji parametrów układu transportowania i przetłaczania zawiesiny.
Źródło:
Archives of Mining Sciences; 2018, 63, 3; 647-663
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and Optimization of Micro Speaker-Box Using a Passive Radiator in Portable Device
Autorzy:
Jiang, Y.-W.
Kwon, J.-H.
Kim, H.-K.
Hwang, S.-M.
Powiązania:
https://bibliotekanauki.pl/articles/176530.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
passive radiator
speaker box
SPL improvement
Sound Pressure Level
Opis:
With the rapid development of multimedia devices such as smart phones and tablet PCs, microspeakers have been recently increasingly used for audio equipment. Improving the acoustic performance of a microspeaker is always a main concern, especially in the low frequency range. To avoid sound cancelation, a microspeaker unit is usually inserted into a speaker box. A passive radiator is also used in speaker boxes to improve the sound performance in the loudspeaker system. However, passive radiators have not been applied into microspeaker system. In this study, a speaker box with a passive radiator was analyzed and optimized to achieve a higher Sound Pressure Level (SPL) in a microspeaker system. The Finite Element Method (FEM), two-degree-of-freedom (DOF) vibration theory, and a plane circular piston sound source were used to study the electromagnetic, vibration, and acoustic characteristics, respectively. Optimization was conducted by changing the mass, stiffness, and size of the passive radiator. Based on the optimized parameters, a new sample was manufactured. The experiment results show that the SPL of the optimized speaker box with a passive radiator is improved by 5 dB at 200 Hz compared with the one without a radiator. The analysis results also matched the experiment results.
Źródło:
Archives of Acoustics; 2017, 42, 4; 753-760
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Dedispersion Transform Method for Extracting the Normal Modes of a Shallow Water Acoustic Signal in the Pekeris Waveguide
Autorzy:
Yang, G.- B.
Lü, L.- G.
Gao, D.- Z.
Jiang, Y.
Liu, H.- N.
Powiązania:
https://bibliotekanauki.pl/articles/177234.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
normal mode extraction
dedispersion transform
Pekeris waveguide
source ranging
Opis:
The normal modes cannot be extracted even in the Pekeris waveguide when the source-receiver distance is very close. This paper introduces a normal mode extraction method based on a dedispersion transform (DDT) to solve this problem. The method presented here takes advantage of DDT, which is based on the waveguide invariant such that the dispersion associated with all of the normal modes is removed at the same time. After performing DDT on a signal received in the Pekeris waveguide, the waveform of resulting normal modes is very close to the source signal, each with different position and amplitude. Each normal mode can be extracted by determining its position and amplitude parameters by applying particle swarm optimization (PSO). The waveform of the extracted normal mode is simply the waveform of the source signal; the real waveform of the received normal mode can then be recovered by applying dispersion compensation to the source signal. The method presented needs only one receiver and is verified with experimental data.
Źródło:
Archives of Acoustics; 2015, 40, 1; 11-18
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł

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