Segmentation MED method based on kurtosis-frequency curve and its application in bearing diagnosis

2021 ◽  
Author(s):  
Chang Yan ◽  
Ming Zhao ◽  
Jing Lin ◽  
Chuancang Ding
Keyword(s):  
Frequency Curve

Principles of designing secondary channels along the river rhine for the benefit of ecological restoration

1995 ◽  
Vol 31 (8) ◽  
pp. 379-382 ◽  
Author(s):  
M. H. I. Schropp
Keyword(s):  
Ecological Restoration ◽  
Threshold Value ◽  
Main Channel ◽  
River Rhine ◽  
Secondary Channel ◽  
Frequency Curve ◽  
Cross Sectional ◽  
Design Value ◽  
Ecological Targets ◽  
Flow Velocities

Secondary channels present a favourable opportunity for ecological restoration of the River Rhine and its branches. However, they have to be fitted into the landscape without affecting existing interests such as inland shipping and protection against flooding. Also the ecological targets have to be met with a minimum of human interference. In this article some design principles for secondary channels are presented in which these aspects are taken into account. To avoid silting up of the secondary channel it is recommended to prevent sediment from entering the channel at all. Flow velocities have to be below the threshold value for initiation of motion of sediment, but still high enough to satisfy the ecological targets. The secondary channel discharge is a function of the maximum allowable aggradation of the main channel. Discharge and flow velocities together determine the required cross-sectional area and thus the design value of the bank slopes. In order to have flowing water in the secondary channel all year round, the thalweg level is to be chosen on the basis of the water level frequency curve of the main channel.

scholarly journals Analysis on the Return Period of “7.26” Rainstorm and Flood in 2017 in the Wudinghe Basin

2018 ◽  
Vol 246 ◽  
pp. 01105
Author(s):  
Shuang-yan Jin ◽  
Wen-yong Gao ◽  
Si-wu Luo ◽  
Ya-jun Gao
Keyword(s):  
Return Period ◽  
Peak Discharge ◽  
Observation Data ◽  
Historical Survey ◽  
Annual Maximum ◽  
Frequency Curve ◽  
Recurrence Period ◽  
Fitting Method ◽  
Curve Fitting Method ◽  
Hydrological Station

The return period of "7.26" rainstorm flood in 2017 in Wudinghe basin is analyzed by the method of P-III distribution. The Lijiahe and Dingjiagou stations with long rainfall observation data in the rainstorm area are selected, and the frequency curve of the annual maximum 24 hours rainfall are established, and the recurrence period of rainfall stations in rainstorm area are estimated according to the parameters determined by the curve fitting method. The frequency curve of the annual maximum peak discharge of Baijiachuan hydrological stations and so on are established, and the return period are analyzed in combination with the historical survey floods. The results show that the return period of Zhaojiabian of heavy rainfall center is about 100 years, and which of the other stations over than 200mm in Wudinghe basin is about 30~90 years; while the return period of the peak discharge of Baijiachuan and Suide hydrological station is about 30 and 20 years respectively.

The Spectrum Segmentation Algorithm of Multimode Vibration Signal Based on Spectral Clustering

2011 ◽  
Vol 121-126 ◽  
pp. 2372-2376
Author(s):  
Dan Dan Wang ◽  
Yu Zhou ◽  
Qing Wei Ye ◽  
Xiao Dong Wang
Keyword(s):  
Wave Packet ◽  
Frequency Domain ◽  
Spectral Clustering ◽  
Clustering Algorithm ◽  
Wave Packets ◽  
Vibration Signal ◽  
Segmentation Algorithm ◽  
Frequency Curve ◽  
Macroscopic Observation ◽  
Spectral Clustering Algorithm

The mode peaks in frequency domain of vibration signal are strongly interfered by strong noise, causing the inaccuracy mode parameters. According to this situation, this paper comes up with the thought of mode-peak segmentation based on the spectral clustering algorithm. First, according to the concept of wave packet, the amplitude-frequency of vibration signal is divided into wave packets. Taking each wave packet as a sample of clustering algorithm, the spectral clustering algorithm is used to classify these wave packets. The amplitude-frequency curve of a mode peak becomes a big wave packet in macroscopic. The experiment to simulation signals indicates that this spectral clustering algorithm could accord with the macroscopic observation of mode segmentation effectively, and has outstanding performance especially in strong noise.

scholarly journals The equations applicable to simple hœmolytic reactions

1926 ◽  
Vol 100 (702) ◽  
pp. 199-222 ◽  
Keyword(s):  
Elementary Theory ◽  
The Other ◽  
Considerable Degree ◽  
Fundamental Importance ◽  
Cell Resistance ◽  
Frequency Curve ◽  
Secondary Reactions ◽  
Sigmoid Curve

The purpose of this paper is to develop and to consider in detail some of the expressions which may be applied to reactions involving simple hæmolytic systems. In doing so, a number of rather unusual conditions have to be considered; these may first be set down. 1. It has been shown (1) that the curves obtained by plotting the amount of hæmolysis, expressed as a percentage of the total, against time, are sigmoid in form, the sigmoid curve often presenting a considerable degree of skewness in one or the other direction. In explanation of this form, it was suggested that the cells of the system present different degrees of resistance to the action of the lysin, these resistances being distributed according to a symmetrical frequency curve, and that the skewness encountered is due to the presence of secondary reactions, principally the reaction of the liberated cell-contents with the lysin. Such suggestions are, in general, in agreement with the findings of Brooks (2), of Fulmer and Buchanan (3), and of other workers on hæmolysis and the allied problem of bacteriolysis. To the two papers mentioned the reader is referred for excellent discussions of both facts and elementary theory, as well as for reviews of the literature. It appears that the bulk of the recent investigation has shown that these variations in cell resistance, and the distribution of these resistances, are of fundamental importance in problems of this kind, and that it is completely fallacious to deal with such problems without allowing for the heterogeneity of the material involved.

SPECIAL ARTICLE

PEDIATRICS ◽  
1954 ◽  
Vol 14 (5) ◽  
pp. 563-564
Author(s):  
Keyword(s):  
Standard Deviation ◽  
Visual Assessment ◽  
Probable Error ◽  
Oral Examination ◽  
Frequency Curve ◽  
Written Examination ◽  
Lower Figure ◽  
Normal Frequency ◽  
The Mean ◽  
Selection Of

THE WRITTEN examination of January 15, 1954, was taken by 515 candidates, a larger number than in any previous year except 1953 when there were 607 candidates Grades ranged from a lowest mark of 32.0 to a highest mark of 89.5 Inspection of the range resulted in the decision to place the passing mark at 51. On this basis there were 32, or 6.2%, who failed and were therefore ineligible for oral examination. The distribution of the grades earned by the 515 candidates is presented in the form of a histogram. As an aid to visual assessment of the nature of the distribution, a normal frequency curve computed from the mean and standard deviation of the data has been superimposed on the diagram. The distribution of the grades is clearly and impressively skewed to the left, that is, the scores tend to be massed at the high end of the scale and spread out at the low end. An examination of this type is relatively sensitive in the zone of poorer scholarship where the selection of failures is to be made and relatively insensitive in the range of higher scholarship. The intrinsic reliability of the examination has again been assessed by comparing the grade made by each candidate on his odd-numbered questions with that earned on his even-numbered questions. The comparison reveals a "probable error of estimate," P.E.m, of 2.39, a lower figure and therefore a higher degree of reliability than yielded by any previous examination. The Committee is pleased that the increase in reliability was accomplished in spite of the fact that the length of the examination was decreased from 250 grading points in 1953 to 200 grading points.

scholarly journals Occurence and biological aspects of the clitoria tree psyllid in Brazil

2005 ◽  
Vol 62 (3) ◽  
pp. 281-285 ◽  
Author(s):  
Manoel Guedes Corrêa Gondim Junior ◽  
Reginaldo Barros ◽  
Fernando Rodrigues da Silva ◽  
Geraldo José Nascimento de Vasconcelos
Keyword(s):  
Sex Ratio ◽  
Incubation Period ◽  
Development Time ◽  
Metropolitan Areas ◽  
Immature Stage ◽  
Frequency Curve ◽  
Nymphal Stage ◽  
Female Longevity ◽  
Biological Aspects

Clitoria fairchildiana (Howard) is a tree largely distributed in Brazil, used for urban arborization. In April 2001, the psyllid Euphalerus clitoriae Burckhardt & Guajará was reported on this plant in the metropolitan areas of Recife, PE, Brazil. This report records the occurrence of E. clitoriae and studies some of its biological aspects in this area. With this purpose, C. fairchildiana leaves were sampled weekly, and E. clitoriae nymphs as well as Aprostocetus sp. larvae and nymphs were collected and counted. The E. clitoriae population ranged from 2 to 90 nymphs per leaflet. The Aprostocetus sp. percentage of parasitism ranged from 3 to 24%. The frequency curve for pygidium width ranged from 120 to 140; 200 to 240; 300 to 380; 460 to 580, and 720 to 820 mm for the first, second, third, fourth, and fifth instars, respectively. The incubation period for E. clitoriae eggs lasted 7.6 days. The nymphal stage lasted 5.7; 4.5; 4.8; 5.0, and 6.1 days for the first, second, third, fourth, and fifth instars, respectively. Development time from egg to adult was 33.7 days. Female longevity 8.6 days, with a daily fecundity of 118 eggs. The total viability of the immature stage was 74%, and the sex ratio was 0.5.

Effects of hypoxia and hypercapnia on geniohyoid contractility and endurance

1991 ◽  
Vol 71 (2) ◽  
pp. 709-715 ◽  
Author(s):  
R. J. Salmone ◽  
E. Van Lunteren
Keyword(s):  
Force Production ◽  
Upper Airway ◽  
Muscle Performance ◽  
Severe Hypoxia ◽  
Force Frequency ◽  
Force Output ◽  
Frequency Curve ◽  
Dilator Muscle ◽  
Index Ratio ◽  
Mild Hypoxia

Sleep apnea and other respiratory diseases produce hypoxemia and hypercapnia, factors that adversely affect skeletal muscle performance. To examine the effects of these chemical alterations on force production by an upper airway dilator muscle, the contractile and endurance characteristics of the geniohyoid muscle were examined in situ during severe hypoxia (arterial PO2 less than 40 Torr), mild hypoxia (PO2 45–65 Torr), and hypercapnia (PCO2 55–80 Torr) and compared with hyperoxic-normocapnic conditions in anesthetized cats. Muscles were studied at optimal length, and contractile force was assessed in response to supramaximal electrical stimulation of the hypoglossal nerve (n = 7 cats) or geniohyoid muscle (n = 2 cats). There were no significant changes in the twitch kinetics or force-frequency curve of the geniohyoid muscle during hypoxia or hypercapnia. However, the endurance of the geniohyoid, as reflected in the fatigue index (ratio of force at 2 min to initial force in response to 40-Hz stimulation at a duty cycle 0.33), was significantly reduced by severe hypoxia but not by hypercapnia or mild hypoxia. In addition, the downward shift in the force-frequency curve after the repetitive stimulation protocol was greater during hypoxia than hyperoxia, especially at higher frequencies. In conclusion, the ability of the geniohyoid muscle to maintain force output during high levels of activation is adversely affected by severe hypoxia but not mild hypoxia or hypercapnia. However, none of these chemical perturbations affected muscle contractility acutely.

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