Two-dimensional fluvial channel model with bank erosion on triangular grid

2004 ◽  
pp. 999-1003 ◽  
Author(s):  
D Farshi ◽  
H Minor
Keyword(s):  
Channel Model ◽  
Bank Erosion ◽  
Triangular Grid ◽  
Two Dimensional

scholarly journals Multiple-Antenna Cooperative Spectrum Sensing Based on the Wavelet Transform and Gaussian Mixture Model

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3863
Author(s):  
Shunchao Zhang ◽  
Yonghua Wang ◽  
Hantao Yuan ◽  
Pin Wan ◽  
Yongwei Zhang
Keyword(s):  
Wavelet Transform ◽  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Spectrum Sensing ◽  
Channel Model ◽  
Cooperative Spectrum Sensing ◽  
Gaussian Mixture ◽  
Multiple Antenna ◽  
Two Dimensional ◽  
Statistical Features

Spectrum sensing is a core technology in cognitive radio (CR) systems. In this paper, a multiple-antenna cooperative spectrum sensor based on the wavelet transform and Gaussian mixture model (MAWG) is proposed. Compared with traditional methods, the MAWG method avoids the derivation of the threshold and improves the performance of single secondary user (SU) spectrum sensing in cases of channel loss and hidden terminal. The MAWG method reduces the noise of the signal which collected by the multiple-antenna SUs through the wavelet transform. Then, the fusion center (FC) extracts the statistical features from the signals that are pre-processed by the wavelet transform. To extract the statistical features, an sensing data fusion method is proposed. The MAWG method divides all SUs that are involved in the cooperative spectrum sensing into two clusters and extracts a two-dimensional feature vector. In order to avoid complicated decision threshold derivation, the Gaussian mixture model (GMM) is used to train a classifier for spectrum sensing according to these two-dimensional feature vectors. Simulation experiments are performed in the κ - μ channel model. The simulation shows that the MAWG can effectively improve spectrum sensing performance under the κ - μ channel model.

scholarly journals A Method of Implementing a 4 × 4 Correlation Matrix for Evaluating the Uplink Channel Properties of MIMO Over-the-Air Apparatus

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6184
Author(s):  
Kazuhiro Honda
Keyword(s):  
Correlation Matrix ◽  
Channel Model ◽  
Multiple Input Multiple Output ◽  
Correlation Coefficients ◽  
Base Station ◽  
Theoretical Formula ◽  
Secondary Wave ◽  
Two Dimensional ◽  
Mimo Antenna ◽  
Channel Properties

This paper presents a method of implementing a 4 × 4 correlation matrix for evaluating the uplink channel properties of multiple-input multiple-output (MIMO) antennas using an over-the-air measurement system. First, the implementation model used to determine the correlation coefficients between the signals received at the base station (BS) antennas via the uplink channel is described. Then, a methodology is introduced to achieve a 4 × 4 correlation matrix for a BS MIMO antenna based on Jakes’ model by setting the initial phases of the secondary wave sources in the two-dimensional channel model. The performance of the uplink channel for a four-element MIMO terminal array antenna is evaluated using a two-dimensional bidirectional fading emulator. The results show that the measured correlation coefficients between the signals received via the uplink channel at the BS antennas using the proposed method are in good agreement with the BS correlation characteristics calculated using Monte Carlo simulation and the theoretical formula, thereby confirming the effectiveness of the proposed method.

Multiple solutions and flow limitation in collapsible channel flows

2000 ◽  
Vol 420 ◽  
pp. 301-324 ◽  
Author(s):  
X. Y. LUO ◽  
T. J. PEDLEY
Keyword(s):  
Boundary Conditions ◽  
Channel Model ◽  
Control Method ◽  
Flow Limitation ◽  
Two Dimensional ◽  
Solution Branch ◽  
Two Dimensional Flow ◽  
Unstable Solutions ◽  
Steady Solutions ◽  
The Stability

Steady and unsteady numerical simulations of two-dimensional flow in a collapsible channel were carried out to study the flow limitation which typically occurs when the upstream transmural pressure is held constant while flow rate and pressure gradient along the collapsible channel can vary independently. Multiple steady solutions are found for a range of upstream transmural pressures and Reynolds number using an arclength control method. The stability of these steady solutions is tested in order to check the correlation between flow limitation and self-excited oscillations (the latter being a consequence of unstable steady solutions). Both stable and unstable solutions are found when flow is limited. Self-excited oscillations and divergence instabilities are observed in certain solution branches. The instability of the steady solutions seems to depend on the unsteady boundary conditions used, i.e. on which parameters are allowed to vary. However, steady solutions associated with the solution branch before flow limitation where the membrane wall bulges are found to be stable for each of the three different boundary conditions employed. We conclude that there is no one to one correlation between the two phenomena in this two dimensional channel model.

scholarly journals BUOYANT DISCHARGES FROM SUBMERGED MULTIPORT DIFFUSERS

1974 ◽  
Vol 1 (14) ◽  
pp. 126
Author(s):  
Donald R.F. Harleman ◽  
Gerhard H. Jirka
Keyword(s):  
Channel Model ◽  
Coastal Zone Management ◽  
Three Dimensional ◽  
Cooling Water ◽  
Frictional Resistance ◽  
Two Dimensional ◽  
Buoyant Jet ◽  
Buoyant Jets ◽  
Dimensional Flow ◽  
Zone Management

The application of submerged multiport diffusers for the discharge of degradable liquid wastes and of heated cooling water from electric power generation forms an important aspect of coastal zone management. Previous buoyant jet models for submerged diffuser discharge have been developed for the limiting case of discharge in unconfined deep water in the form of rising buoyant jets. These models can be used for sewage diffusers, but are not applicable for diffusers in shallow receiving water with low buoyancy, the type used for thermal discharges ("thermal diffusers"). A multiport diffuser will produce a general three-dimensional flow. Yet the predominantly two dimensional flow which exists in the center portion of the three-dimensional diffuser can be analyzed as a two-dimensional "channel model". Theoretical solutions for diffuser-induced dilutions are derived for the two-dimensional case and verified experimentally. Furthermore, the theory can be applied to the three-dimensional situation by requiring equivalency of far-field effects, that is the frictional resistance governing the diffuser-induced motion at larger distances from the diffuser line.

A Numerical Analysis of Phonation Using a Two-Dimensional Flexible Channel Model of the Vocal Folds

2001 ◽  
Vol 123 (6) ◽  
pp. 571-579 ◽  
Author(s):  
Tadashige Ikeda ◽  
Yuji Matsuzaki ◽  
Tatsuya Aomatsu
Keyword(s):  
Channel Model ◽  
Flow Direction ◽  
Speech Sound ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Two Dimensional ◽  
Threshold Values ◽  
One Dimensional ◽  
Frequency Components ◽  
Main Flow Direction

A two-dimensional flexible channel model of the vocal folds coupled with an unsteady one-dimensional flow model is presented for an analysis of the mechanism of phonation. The vocal fold is approximated by springs and dampers distributed in the main flow direction that are enveloped with an elastic cover. In order to approximate three-dimensional collision of the vocal folds using the two-dimensional model, threshold values for the glottal width are introduced. The numerical results show that the collision plays an important role in speech sound, especially for higher resonant frequency components, because it causes the source sound to include high-frequency components.

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