The Research of Chaos Time Series on Chatter Signal Recognition

2013 ◽  
Vol 584 ◽  
pp. 137-141
Author(s):  
Yong Xiang Jiang ◽  
Bing Du ◽  
Pan Zhang ◽  
San Peng Deng ◽  
Yu Ming Qi
Keyword(s):  
Time Series ◽  
Vibration Signal ◽  
Signal Recognition ◽  
Analysis Method ◽  
Correlation Integral ◽  
Discrete Dynamic System ◽  
Nonlinear Input ◽  
Before And After ◽  
Online Detecting ◽  
Milling Chatter

The online detecting of chatter is the key technology to improve the machining quality. Based on the nonlinear chaos control theory in discrete dynamic system, the processing vibration signal discrete time series is taken as system nonlinear input, the C-C algorithm and correlation integral was used to determine appropriate embedding dim m and time delay τ. Then the phase space is reconstructed by discrete vibration signal. In milling chatters experiment, the time series analysis method is used to get the phase diagram before and after chatter. The chatter phase chart shows the characteristics of chaos and recognized the milling chatter.

The Mechanical Fault Diagnosis Method Based on EMD and Time Series Analysis

2014 ◽  
Vol 602-605 ◽  
pp. 2330-2333 ◽  
Author(s):  
Jun Ma ◽  
Shi Hai Zhang
Keyword(s):  
Time Series ◽  
Fault Diagnosis ◽  
Time Series Analysis ◽  
Mechanical Vibration ◽  
Vibration Signal ◽  
Vibration Monitoring ◽  
Analysis Method ◽  
Series Analysis ◽  
Mode Decomposition ◽  
Empirical Mode Decomposition Method

It is the precondition of vibration fault diagnosis technology that appropriate signal analysis method is applied to separate mechanical fault character message from vibration monitoring signal. Based on the characteristics of multi-exciting, multi-model, non-stationary, nonlinear of the complex mechanical vibration signal, the EMD (Empirical Mode Decomposition) method is firstly applied to decompose the most refined IMF (Intrinsic Mode Function) components of vibration monitoring signal, and then the time series analysis method is applied to estimate power spectrums of IMF components and separate the fault character messages. The feasibility and advantage of the associated method are proved by analyzing the diesel engine crankshaft vibration monitoring signal in the paper.

ANALISIS PENGARUH PEMBANGUNAN JALAN LAYANG JANTI TERHADAP PERKEMBANGAN TATA RUANG KAWASAN JANTI STUDI KASUS : KAWASAN JANTI, DESA CATURTUNGGAL, KABUPATEN SLEMAN, D. I. YOGYAKARTA

2017 ◽  
Vol 11 (3) ◽  
pp. 255
Author(s):  
Jeky El Boru
Keyword(s):  
Road Network ◽  
Open Space ◽  
Qualitative Description ◽  
Analysis Method ◽  
Open Spaces ◽  
The Road ◽  
Before And After ◽  
Linkage Method ◽  
The Impact ◽  
Parking Place

Abstract: This research aims to analyze the impact of Janti Flyover Construction toward the growth of layout at Janti Urban Area, including structured space, open space, and linkage. Method used for data collecting are observation, air photograph monitoring, and interview, whereas the analysis method is qualitative description, which is the superimposed method of two layers, that are the layout condition before and after flyover construction. The result shows that the impact of Janti Flyover construction can be seen on building mass (solid), the increasing number of open spaces, including the road network, parking place, and park, whereas the relation between spaces, visually and structurally, can be seen on the growth of buildings which have new shapes and styles, therefore the performance of the overall building does not have a proportional shape. Considering Janti Street at the collective relation, its role is getting stronger as the main frame road network.Keywords: Flyover construction, layout changing, Janti AreaAbstrak: Penelitian ini bertujuan untuk menganalisis pengaruh pembangunan Jalan Layang Janti terhadap perkembangan tata ruang Kawasan Janti, meliputi ruang terbangun, ruang terbuka, serta hubungan antar ruang (“linkage”). Metode pengumpulan data dilakukan melalui observasi, pengamatan foto udara, dan wawancara; sedangkan metode analisis melalui deskripsi secara kualitatif yang berupa “superimposed method” dari dua lapisan kondisi lahan, yakni kondisi tata ruang sebelum dan sesudah pembangunan jalan layang. Hasil penelitian menunjukkan bahwa pengaruh pembangunan Jalan Layang Janti terdapat pada massa bangunan (“solid”), pertambahan ruang terbuka yang berupa jaringan jalan, parkir, dan taman; sedangkan pada hubungan antar ruang ̶ secara visual dan struktural ̶ yakni tumbuhnya bangunan dengan bentuk dan gaya baru, sehingga bentuk tampilan bangunan secara keseluruhan tidak proporsional. Pada hubungan kolektif, Jalan Janti semakin kuat perannya sebagai kerangka utama jaringan jalan.Kata kunci : Pembangunan jalan layang, tata ruang, Kawasan Janti

Print Media and the Political Reform in Ethiopia

2019 ◽  
Vol 14 ◽  
pp. 3356-3371
Author(s):  
Negesse Gessese
Keyword(s):  
Social Changes ◽  
Analysis Method ◽  
Sources Of Information ◽  
Attribution Of Responsibility ◽  
Societal Issues ◽  
Content Selection ◽  
Period 2 ◽  
Content Analysis Method ◽  
Before And After ◽  
Issue Frames

This research examines the agenda and frames used by the Reporter newspaper editorial coverage of issues and actors before and after the reform in Ethiopia. The study applies a quantitative content analysis method and examined 99 (Period 1 = 57 and Period 2 = 42) editorials in all periods. The source of data and the period of data collection were purposely selected. The results indicated that societal issues, government, and party issues were frequent in both periods. The professional journalist was the only Author in both periods. More government criticism and more reforms were mentioned before the reform. Compared with editorials published before and after the reform, noticeable changes were observed in government critique, attribution of responsibility frames, human interest frames and economic issue frames. However, content selection, sources of information, mentioned reforms, conflict relationship frames, and ideological frames didn’t have relationship with the date of publication. Finally, the Reporter editorials coverage did change significantly in many respects, although it is difficult to determine the causes of the changes—economic factors, reduced political control, social changes or globalization forces.

scholarly journals Statistical and Criticality Analysis of the Lower Ionosphere Prior to the 30 October 2020 Samos (Greece) Earthquake (M6.9), Based on VLF Electromagnetic Propagation Data as Recorded by a New VLF/LF Receiver Installed in Athens (Greece)

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 676
Author(s):  
Dimitrios Z. Politis ◽  
Stelios M. Potirakis ◽  
Yiannis F. Contoyiannis ◽  
Sagardweep Biswas ◽  
Sudipta Sasmal ◽  
...  
Keyword(s):  
Time Series ◽  
Fresnel Zone ◽  
Lower Ionosphere ◽  
Propagation Path ◽  
Northern Coast ◽  
Analysis Method ◽  
Ionospheric Propagation ◽  
Amplitude Data ◽  
Natural Time ◽  
Criticality Analysis

In this work we present the statistical and criticality analysis of the very low frequency (VLF) sub-ionospheric propagation data recorded by a VLF/LF radio receiver which has recently been established at the University of West Attica in Athens (Greece). We investigate a very recent, strong (M6.9), and shallow earthquake (EQ) that occurred on 30 October 2020, very close to the northern coast of the island of Samos (Greece). We focus on the reception data from two VLF transmitters, located in Turkey and Israel, on the basis that the EQ’s epicenter was located within or very close to the 5th Fresnel zone, respectively, of the corresponding sub-ionospheric propagation path. Firstly, we employed in our study the conventional analyses known as the nighttime fluctuation method (NFM) and the terminator time method (TTM), aiming to reveal any statistical anomalies prior to the EQ’s occurrence. These analyses revealed statistical anomalies in the studied sub-ionospheric propagation paths within ~2 weeks and a few days before the EQ’s occurrence. Secondly, we performed criticality analysis using two well-established complex systems’ time series analysis methods—the natural time (NT) analysis method, and the method of critical fluctuations (MCF). The NT analysis method was applied to the VLF propagation quantities of the NFM, revealing criticality indications over a period of ~2 weeks prior to the Samos EQ, whereas MCF was applied to the raw receiver amplitude data, uncovering the time excerpts of the analyzed time series that present criticality which were closest before the Samos EQ. Interestingly, power-law indications were also found shortly after the EQ’s occurrence. However, it is shown that these do not correspond to criticality related to EQ preparation processes. Finally, it is noted that no other complex space-sourced or geophysical phenomenon that could disturb the lower ionosphere did occur during the studied time period or close after, corroborating the view that our results prior to the Samos EQ are likely related to this mainshock.

scholarly journals Complexity traits and synchrony of cryptocurrencies price dynamics

2021 ◽  
Author(s):  
Davide Provenzano ◽  
Rodolfo Baggio
Keyword(s):  
Time Series ◽  
Complex Network ◽  
Complex Structures ◽  
Slope Parameter ◽  
Exponential Distributions ◽  
Horizontal Visibility ◽  
Time Period ◽  
Before And After ◽  
Visibility Algorithm ◽  
Similar Complex

AbstractIn this study, we characterized the dynamics and analyzed the degree of synchronization of the time series of daily closing prices and volumes in US$ of three cryptocurrencies, Bitcoin, Ethereum, and Litecoin, over the period September 1,2015–March 31, 2020. Time series were first mapped into a complex network by the horizontal visibility algorithm in order to revel the structure of their temporal characters and dynamics. Then, the synchrony of the time series was investigated to determine the possibility that the cryptocurrencies under study co-bubble simultaneously. Findings reveal similar complex structures for the three virtual currencies in terms of number and internal composition of communities. To the aim of our analysis, such result proves that price and volume dynamics of the cryptocurrencies were characterized by cyclical patterns of similar wavelength and amplitude over the time period considered. Yet, the value of the slope parameter associated with the exponential distributions fitted to the data suggests a higher stability and predictability for Bitcoin and Litecoin than for Ethereum. The study of synchrony between the time series investigated displayed a different degree of synchronization between the three cryptocurrencies before and after a collapse event. These results could be of interest for investors who might prefer to switch from one cryptocurrency to another to exploit the potential opportunities of profit generated by the dynamics of price and volumes in the market of virtual currencies.

scholarly journals Changes in the Use of Broad-Spectrum Antibiotics after Cefepime Shortage: a Time Series Analysis

2011 ◽  
Vol 56 (2) ◽  
pp. 989-994 ◽  
Author(s):  
C. Plüss-Suard ◽  
A. Pannatier ◽  
C. Ruffieux ◽  
A. Kronenberg ◽  
K. Mühlemann ◽  
...  
Keyword(s):  
Time Series ◽  
Pseudomonas Aeruginosa ◽  
Broad Spectrum ◽  
Interrupted Time Series ◽  
Antibiotic Policy ◽  
Content Type ◽  
Broad Spectrum Antibiotics ◽  
Before And After ◽  
Alternative Antibiotic ◽  
The Impact

ABSTRACTThe original cefepime product was withdrawn from the Swiss market in January 2007 and replaced by a generic 10 months later. The goals of the study were to assess the impact of this cefepime shortage on the use and costs of alternative broad-spectrum antibiotics, on antibiotic policy, and on resistance ofPseudomonas aeruginosatoward carbapenems, ceftazidime, and piperacillin-tazobactam. A generalized regression-based interrupted time series model assessed how much the shortage changed the monthly use and costs of cefepime and of selected alternative broad-spectrum antibiotics (ceftazidime, imipenem-cilastatin, meropenem, piperacillin-tazobactam) in 15 Swiss acute care hospitals from January 2005 to December 2008. Resistance ofP. aeruginosawas compared before and after the cefepime shortage. There was a statistically significant increase in the consumption of piperacillin-tazobactam in hospitals with definitive interruption of cefepime supply and of meropenem in hospitals with transient interruption of cefepime supply. Consumption of each alternative antibiotic tended to increase during the cefepime shortage and to decrease when the cefepime generic was released. These shifts were associated with significantly higher overall costs. There was no significant change in hospitals with uninterrupted cefepime supply. The alternative antibiotics for which an increase in consumption showed the strongest association with a progression of resistance were the carbapenems. The use of alternative antibiotics after cefepime withdrawal was associated with a significant increase in piperacillin-tazobactam and meropenem use and in overall costs and with a decrease in susceptibility ofP. aeruginosain hospitals. This warrants caution with regard to shortages and withdrawals of antibiotics.

Finite Deformation Stiffness of Sliding Elastomeric Bearings

2011 ◽  
Vol 374-377 ◽  
pp. 1858-1862
Author(s):  
Jian Chun Xiao ◽  
Peng Liu ◽  
Ke Jian Ma
Keyword(s):  
Parametric Analysis ◽  
Steel Plates ◽  
Structural Behavior ◽  
Analysis Method ◽  
Force Vector ◽  
Elastomeric Bearings ◽  
Before And After ◽  
Bearing Stiffness ◽  
Vector Formula

Anchor bolts are set in some elastomeric bearings of large-span column-supported spatial steel roofs. Besides helping the bearing in-site assembly, the bolts play the roles of sliding position limitation and vertical anchorage. To analyze the effect of bearings on nonlinear structural behavior, the bearing stiffness change is studied just before and after the elastomer pad is in contact with the bolts. For the bearing that the pad is glued with the top/bottom steel plates, three kinds of relation of pad and bolts are discussed and an approximate horizontal stiffness formula is obtained with parametric analysis method. Based on the analysis results a stiffness expression for sliding elastomeric bearings is deduced. To solve the computational problem caused by the bearing stiffness changes, an improved imbalance force vector formula is proposed. Case study shows that the bolts have influence upon the computed results more significantly.

Damage Assessment of the Attacked Airports Based on Image Analysis

2013 ◽  
Vol 321-324 ◽  
pp. 1168-1171
Author(s):  
Xiao Nan Zhang ◽  
Jun Feng Yang ◽  
Si Liang Du ◽  
Jun Zhi
Keyword(s):  
Damage Assessment ◽  
Automatic Method ◽  
Analysis Method ◽  
Image Information ◽  
Damage Degree ◽  
Before And After ◽  
Battle Damage Assessment ◽  
Damage Extent ◽  
Modern War ◽  
Assessment Result

Battle Damage Assessment (BDA) is to assess the damage degree of enemy’s target after being attacked. In modern war, combat commanders always make decision on the basis of BDA. In this paper, an automatic method for assessing the damage extent of an attacked airport based on the image taken before and after a strike is described. Firstly, the airport blockade condition is analyzed and damage assessment criteria of airport are proposed. Secondly, three steps of the image information pretreatment are carried out and a reliability analysis method of image information is proposed. Lastly, damage assessment result is calculated to verify the validity and availability of the proposed method.

DYNAMICAL ESTIMATION OF CALENDAR EFFECTS

2006 ◽  
Vol 06 (01) ◽  
pp. L7-L15
Author(s):  
ALEXANDROS LEONTITSIS
Keyword(s):  
Dynamical System ◽  
Time Series ◽  
Noise Level ◽  
Nonlinear Dynamical System ◽  
Main Tool ◽  
Experimental Results ◽  
Accurate Estimation ◽  
Nonlinear Dynamical ◽  
Correlation Integral ◽  
Calendar Effects

The paper introduces a method for estimation and reduction of calendar effects from time series, which their fluctuations are governed by a nonlinear dynamical system and additive normal noise. Calendar effects can be considered deviations of the distribution(s) of particular group(s) of observations that have a common characteristic related to the calendar. The concept of this method is the following: since the calendar effects are not related to the dynamics of the time series, the accurate estimation and reduction will result a time series with a smaller amount of noise level (i.e. more accurate dynamics). The main tool of this method is the correlation integral, due to its inherit capability of modeling both the dynamics and the additive normal noise. Experimental results are presented on the Nasdaq Cmp. index.

Online Monitoring Recognition Theory Based on the Time Series of Chatter

2013 ◽  
Vol 819 ◽  
pp. 160-164
Author(s):  
Yong Xiang Jiang ◽  
Bing Du ◽  
Pan Zhang ◽  
San Peng Deng ◽  
Yu Ming Qi
Keyword(s):  
Time Series ◽  
Chaotic Dynamics ◽  
Online Monitoring ◽  
Vibration Signal ◽  
Threshold Value ◽  
Coarse Grained ◽  
Attractor Dimension ◽  
Machining Chatter ◽  
Recognition Theory ◽  
On Line

On-line monitoring recognition for machining chatter is one of the key technologies in manufacturing. Based on the nonlinear chaotic control theory, the vibration signal discrete time series for on-line monitoring indicator is studed. As in chatter the chaotic dynamics process attractor dimension is reduced, the KolmogorovSinai entropy (K-S) index is extracted to reflected the regularity of workpiece chatter, then the k-S entropy is simplified by coarse - grained entropy rate (CER), which can easily evaluated as chatter online monitoring threshold value. The milling test shows that the CER have a sharp decline when chatter occurre, and can quickly and accurately forecast chatter.

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