scholarly journals A Truncated Matrix Completion Algorithm Using Prior Information for Wind Turbine Clutter Suppression

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Minghe Mao ◽  
Tianhe Li ◽  
Mingwei Shen ◽  
Ning Cao ◽  
Rui Shi ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Prior Information ◽  
Matrix Completion ◽  
Diagonal Element ◽  
Mean Value ◽  
Singular Value ◽  
Clutter Suppression ◽  
Shrinking Process ◽  
The Mean ◽  
Recovery Result

The conventional matrix completion (MC) regularizes each singular value equally, and thus the rank cannot be well approximated, which greatly limits the flexibility and accuracy of MC usage. In this paper, a truncated MC algorithm using prior information to determine the threshold while generating the target rank is proposed for the wind turbine clutter suppression of weather radar. During the singular value shrinking process, an appropriate threshold is selected to obtain the optimal approximation of the sampling matrix. Specifically, the mean value of the diagonal element in the recovered weather matrix is calculated to improve the robustness of the recovery result effectively. Simulation results demonstrate that the proposed algorithm reduces the computational complexity as well as further improves the MC accuracy and realizes the effective suppression of the wind turbine clutter.

scholarly journals A new method of calculating the mean value of 1/ r 3 for keplerian systems in quantum mechanics

1934 ◽  
Vol 143 (850) ◽  
pp. 679-681 ◽  
Keyword(s):  
Quantum Mechanics ◽  
Diagonal Element ◽  
Mean Value ◽  
Usual Method ◽  
Matrix Elements ◽  
Generating Series ◽  
The Mean ◽  
Schrödinger Form ◽  
Interesting Alternative ◽  
Keplerian Systems

The usual method of calculating the diagonal matrix elements of an integral power of the radius r in an inverse square quantum system is that due to Waller. His procedure is based on the Schrödinger form of the theory, and utilizes in particular the generating series for the Langueree polynomials. For negative powers, Dirac's very elegant theory of "q-numbers," developed in these 'proceedings' during the early days of quantum mechanics, furnishes an interesting alternative method which appears to have been overlooked, and which we believe is easier. From his theory the following rule can be derived: Suppose that we desire the mean value (diagonal element) of 1/r s , where s is an integer greater than unity. We write down the experssion with A(α l + β l e - i x + γ l e i x ) s-2 A = 16π 4 m 2 z 2 e 4 /( l + ½) n 3 h 4 , α l = 4π 2 m z e 2 / h 2 l ( l +1), β l = 2π 2 m Z e 2 / h 2 ( l +½)( l +1)[1-( l +1) 2 / n 2 ]½, γ l = 2π 2 m z e 2 / h 2 l ( l +½)[1- l 2 / n 2 ]½.

Robust Design Optimization of Gear Parameters for a Wind Turbine Using Interval Analysis

2010 ◽  
Vol 224 (10) ◽  
pp. 2235-2245 ◽  
Author(s):  
R Dong ◽  
W Sun ◽  
H Xu
Keyword(s):  
Wind Turbine ◽  
Design Optimization ◽  
Robust Design ◽  
Optimization Method ◽  
Mean Value ◽  
Robust Design Optimization ◽  
Upper And Lower Bounds ◽  
Interval Numbers ◽  
Minimum Sensitivity ◽  
The Mean

A robust design optimization method is suggested to optimize the system parameters of a gear transmission for a wind turbine with minimum sensitivity of fatigue strength to variations in uncertain application factor, dynamic load coefficient, material property parameters, and other coefficients representing unknown working condition. Interval numbers are employed to model the uncertainties by which only the upper and lower bounds are needed. Based on interval mathematics, the original real-valued objective and constraint functions are replaced by the interval-valued functions, which directly represent the variation bounds of the new functions under uncertainty. The single-objective function is converted into two-objective functions for minimizing the mean value and the variation, and the constraint functions are reformulated with the acceptable robustness level, resulting in a bi-level mathematical model. The optimization results of gear parameter demonstrate the validity and feasibility of the presented method.

scholarly journals An innovative method to calibrate a spinner anemometer without the use of yaw position sensor

2016 ◽  
Vol 1 (2) ◽  
pp. 143-152 ◽  
Author(s):  
Giorgio Demurtas ◽  
Nick Gerardus Cornelis Janssen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Calibration Method ◽  
Mean Value ◽  
Position Sensor ◽  
Flow Angle ◽  
Angle Measurements ◽  
Innovative Method ◽  
Calibration Methods ◽  
The Mean

Abstract. A spinner anemometer can be used to measure the yaw misalignment and flow inclination experienced by a wind turbine. Previous calibration methods used to calibrate a spinner anemometer for flow angle measurements were based on measurements of a spinner anemometer with default settings (arbitrary values, generally k1,d  =  1 and k2,d  =  1) and a reference yaw misalignment signal measured with a yaw position sensor. The yaw position sensor is normally present in wind turbines for control purposes; however, such a signal is not always available for a spinner anemometer calibration. Therefore, an additional yaw position sensor was installed prior to the spinner anemometer calibration. An innovative method to calibrate the spinner anemometer without a yaw positions sensor was then developed. It was noted that a non-calibrated spinner anemometer that overestimates (underestimates) the inflow angle will also overestimate (underestimate) the wind speed when there is a yaw misalignment. The new method leverages the non-linearity of the spinner anemometer algorithm to find the calibration factor Fα by an optimization process that minimizes the dependency of the wind speed on the yaw misalignment. The new calibration method was found to be rather robust, with Fα values within ±2.7 % of the mean value for four successive tests at the same rotor position.

Application of the state deterioration evolution based on bi-spectrum in wind turbine

2013 ◽  
Vol 228 (11) ◽  
pp. 1958-1967 ◽  
Author(s):  
Xu Xiaoli ◽  
Jiang Zhanglei ◽  
Wang Hongjun ◽  
Wu Guoxin ◽  
Zuo Yunbo ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Graphical Representation ◽  
Vibration Signal ◽  
Mean Value ◽  
The State ◽  
Low Speed ◽  
Feature Parameters ◽  
Normal Distribution Curve ◽  
Actual Equipment ◽  
The Mean

Concerning the problem of large rotating machinery like wind turbine which runs in low speed and non-stationary state, this research mainly focuses on separating fault trend feature from non-fault feature and the method of state deterioration evolution based on bi-spectrum. Firstly, the experimental signal such as low-speed startup vibration signal of rotor test rig in the normal state and a plurality of unbalanced state have been collected. Bi-spectrum method is applied to extract fault feature which submerged in complex background noise. On the basis of bi-spectrum analysis, the fault feature evolutionary matrix is defined to represent the state of equipment deterioration. The eigenvalues of fault feature evolutionary matrix are computed and fitted to a normal distribution curve, from which the mean value and variance are taken as fault feature parameters. Fault feature parameters are verified effectively by experiments. Finally, depending on fault feature parameters, graphical representation of state deterioration evolution is established. It is beneficial to provide guidelines for equipment deterioration trend. This method is applied to analyze the real vibration signal of wind turbine with the type of WD646/600 KW, and actual equipment condition verified the effectiveness of the proposed method.

scholarly journals An innovative method to calibrate a spinner anemometer without use of yaw position sensor

2016 ◽  
Author(s):  
Giorgio Demurtas ◽  
Nick Gerardus Cornelis Janssen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Calibration Method ◽  
Mean Value ◽  
Position Sensor ◽  
Flow Angle ◽  
Angle Measurements ◽  
Innovative Method ◽  
Calibration Methods ◽  
The Mean

Abstract. A spinner anemometer can be used to measure the yaw misalignment and flow inclination experienced by a wind turbine. Previous calibration methods used to calibrate a spinner anemometer for flow angle measurements were based on measurements of a spinner anemometer with default settings and a reference yaw misalignment signal measured measured with a yaw position sensor. The yaw position sensor is normally present in wind turbines for control purposes, however, such a signal is not always available for a spinner anemometer calibration. Therefore, an additional yaw position sensor has been installed prior to the spinner anemometer calibration. An innovative method to calibrate the spinner anemometer without a yaw positions sensor was then developed. It was noted that a non calibrated spinner anemometer that overestimate (underestimate) the inflow angle will also overestimate (underestimate) the wind speed when there is a yaw misalignment. The new method leverage on the non linearity of the spinner anemometer algorithm to find the calibration factor Fα by an optimization process that minimizes the dependency of the wind speed to the yaw misalignment. The new calibration method was found to be rather robust with Fα values within ±2.7 % of the mean value for four successive tests at the same rotor position.

Long-period modulated superstructures in Pd-12.5 at.%Ce and Pd-15 at.%Ce alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 164-165
Author(s):  
Noriyuki Kuwano ◽  
Masaru Itakura ◽  
Kensuke Oki
Keyword(s):  
Electron Microscopy ◽  
Mean Value ◽  
Heavy Elements ◽  
Arc Furnace ◽  
X Ray ◽  
Long Period ◽  
Ultra High Purity ◽  
Heat Treated ◽  
Atomic Scattering ◽  
The Mean

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski
Keyword(s):  
Human Subjects ◽  
Coronary Thrombosis ◽  
Mean Value ◽  
Healthy Human ◽  
Protamine Sulphate ◽  
Soluble Fibrin ◽  
Fibrin Monomer ◽  
Dog Plasma ◽  
The Mean ◽  
Precipitable Protein

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Determination of Plasminogen in Clots and Thrombi

1966 ◽  
Vol 16 (01/02) ◽  
pp. 038-050 ◽  
Author(s):  
Ulla Hedner ◽  
Inga Marie Nilsson ◽  
B Robertson
Keyword(s):  
Mean Value ◽  
Main Mechanism ◽  
Clot Lysis ◽  
Post Mortem ◽  
Digestion Time ◽  
Normal Volunteers ◽  
Casein Solution ◽  
The Mean

SummaryThe plasminogen content was determined by a casein method in plasma and serum from 20 normal volunteers. The mean plasminogen content was found to be 10.1 ACU (the arbitrary caseinolytic unit defined in such a way that using a 3% casein solution and a digestion time of 20 min. at 37°C, 10 ACU gave an extinction of 0.300). No difference between serum and plasma regarding the plasminogen content was found.Plasminogen was determined in drained and drained plus washed clots prepared from 2 ml plasma. The highest values found in the drained clots were 0.9 ACU/clot and 0.2 ACU/clot in the drained plus washed clots.Plasminogen was also determined in drained and drained plus washed clots prepared from plasma with added purified plasminogen. The plasminogen was recovered in the washing fluid. According to these tests, then, purified added plasminogen is washed out of the clots.The plasminogen content of 20 thrombi obtained post mortem was also determined. The mean value was found to be 0.7 ACU/cm thrombus. Judging from our results, the “intrinsic clot lysis theory” is not the main mechanism of clot dissolution.

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