Assessing groundwater level variability in response to climate change: A case study of large plain areas by Haidi Wu, Xueyan Ye, Xinqiang Du, Wuxiang Wang, Hongyan Li, Weihong Dong

“…The analysis employs univariate linear trend analysis, the Mann-Kendall test, Morlet wavelet analysis, and cross-wavelet analysis. New hydrological insights for the region: The findings indicate that the groundwater level cycle is approximately 28 years, which corresponds with the atmospheric precipitation cycle. …”
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Analysis of Water and Sediment Characteristics in Rongjiang River Basin by AO Liangting

“…The Rongjiang River Basin is a tidal reach,where the movement of water and sediment is complicated.Over the years,sediment deposition and soil erosion are serious.Hence,the study of the variations of water and sediment in the Rongjiang River Basin is of great significance for water area management and river management in the basin.Upon the comprehensive analysis of the water and sediment data of Dongqiaoyuan Hydrological Station in the mainstream of Rongjiang River from 1953 to 2017,the trend analysis of the water and sediment sequence is carried out by the moving average method and Mann-Kendall trend test.The mutation analysis is made by the Mann-Kendall mutation test and ordered cluster analysis.Meanwhile,Morlet wavelet analysis is used to discuss the periodicity of the water and sediment process.The characteristics,variations,and influencing factors of water and sediment in the Rongjiang River Basin are obtained to provide theoretical support and a digital model for further study of the characteristics of water and sediment in the basin.…”
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Using Wavelets to Understand the Relationship between Mortgages and Gross Domestic Product in Spain by C. González-Concepción, M. C. Gil-Fariña, C. Pestano-Gabino

“…We use wavelet multiresolution decomposition and cross-wavelet analysis to reveal certain properties in financial data related to mortgages to households and gross domestic product data in Spain. …”
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Wavelet Based Demodulation of Vibration Signals Generated by Defects in Rolling Element Bearings by C.T. Yiakopoulos, I.A. Antoniadis

“…The method fully exploits the underlying physical concepts of the modulation mechanism, present in the vibration response of faulty bearings, using the excellent time-frequency localization properties of the wavelet analysis. The choice of the specific wavelet family is marginal to their overall effect, while the necessary number of wavelet levels is quite limited. …”
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Research on the Correlation between Information and Communication Technology Development and Consumer Spending Based on Artificial Intelligence and Time Series Econometric Model by Chaozhi Fan, Siong Hook Law, Saifuzzaman Ibrahim, N. A. M. Naseem

“…Moreover, this paper organically combines the advantages of wavelet analysis and hidden Markov model to construct a wavelet domain hidden Markov chain model. …”
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Analysis of Meteorological Drought Cycle Basedon Wavelet Function in Zhanjiang by ZHANG Desheng, CHEN Yafen, TAN Senming

“…Based on monthly rainfall data of 19 stations from 1966 to 2015 in Zhanjiang City, Guangdong Province, which is selected as the research area, this paper conducts the spatial modal decomposition of regional meteorological drought distribution by using the standardized precipitation index of 6 months and the rotated empirical orthogonal function, and calculates the drought period of different spatial modes through wavelet analysis. The results show that the spatial distribution of drought in Zhanjiang can be decomposed into 6 spatial modes. …”
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ROLLING BEARING FAULT DIAGNOSIS MЕТHOD BASED ON MORLET WAVELET AND CART DECISION TREE by LIU JunLi, MIAO BingRong, ZHANG Ying, Ll YongJian, HUANG Zhong

“…Firstly, the Morlet wavelet analysis method and moving window method were used to process samples of the measured vibration signal of bearing. …”
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WAVELET IDENTIFICATION OF 1/fPROCESS FOR THE FRACTAL DIMENSION OF MACHINED SURFACE TOPOGRAPHY by WEN ShuHua, ZHAO Yue, ZHANG XueLiang, CHEN YongHui, LAN GuoSheng

“…The calculation results of the wavelet identification of 1/f process are compared with the box counting method, variance method, R/S analysis method, power spectral density method（PSD）, root mean square method（RMS）, structure function method and the method of equations, and the results show that the wavelet identification of 1/f process is more accurate and more convenient than other algorithms, further shows that the wavelet analysis method can be well applied to the multi-scale fractal analysis on the surface. …”
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Memories of the Gold Foreign Exchange Market Based on a Moving V-Statistic and Wavelet-Based Multiresolution Analysis by Peng Zheng, Bin Liu, Zhongli Zhou

“…Finally, we check the moving V-statistic estimation in wavelet analysis in the same condition; the paper selects the volatilities of the gold foreign exchange rates to evaluate the moving V-statistic. …”
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Analysis of Spatiotemporal Variation Characteristics of Rainfall Erosivity in Guangdong Province from 1960 to 2018 by DENG Panpan, QIN Beilei, DU Liya

“…In order to analyze the spatiotemporal variation characteristics of rainfall erosivity in Guangdong Province,the daily rainfall data from 86 stations in Guangdong Province during 1960—2018 were systematically studied by using methods such as the daily rainfall erosivity model,Mann-Kendall trend,and wavelet analysis.The results show that the mean rainfall erosivity in Guangdong Province from 1960 to 2018 is 9 839 (MJ·mm)/(hm²·h·a),and it fluctuates in the range of 7 137~14 339 (MJ·mm)/(hm²·h·a).In terms of spatial distribution,the rainfall erosivity gradually increases from north to south and is strong in coastal areas.Most stations in Guangdong Province show a rising trend.The interpolation results show that except for several regions in eastern Guangdong Province,the rainfall erosivity in other regions all increases.The periodic analysis shows that the principal variation period of annual rainfall erosivity from 1960 to 2018 is seven years,and there is an oscillation period of two to eight years.This study can provide some guidance for water and soil conservation and other works in Guangdong Province.…”
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Received Power Attenuation Analysis Based on Wavelet for Reflection-Style Optical Antenna Deformations in Free-Space Laser Communications by Wanqing Xie, Liying Tan, Jing Ma, Yang Liu

“…Diversified deformations on reflection-style optical antennas caused by processing technique and complex outer-space environment in free-space laser communications are modeled by wavelet analysis. Influence due to the deformations on received power is studied by distortion attenuation factor based on the model. …”
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Risk Analysis of Waterlogging under Combination of Short-duration Heavy Rainfall and Tidal Level in Foshan City by YANG Fan, XU Liang, HAN Jing

“…In orderto explore the probability of waterlogging risks in a specific city and provide scientific basisfor the study of urban waterlogging risks in the Pearl River Delta region, from the perspective ofthe causes of waterlogging, this paper takes Foshan as a typical research area, systematicallyanalyzes the probability of encountering storms and high tide levels, constructs a probabilisticmodel for the risk of encounter of rainstorm and high tidal level in urban area of Foshan, andquantitatively evaluates the encounter probabilities and change trend under multiple combinationsof rainstrom and tidal levels in urban area of Foshan by the time-series trend analysis, stormfrequency change statistics, sequence wavelet analysis, and Copula function. The study shows thatsince 2000, the number of rainstorms in urban area of Foshan increased, and the encounterprobability of rainstorm and high tidal level was high, so the risk probability was high. …”
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Change Characteristics and Correlation Analysis of Temperature and Rainfall in Recent 60 Years in Suzhou, Jiuquan by FENG Shiyuan, LI Qingguo, GUO Yang, ZHENG Shuai

“…In order to reveal the change trend and rule of temperature and rainfall in the Suzhou,Jiuquan, this paper analyzes the rainfall and temperature data of the study area from 1951 to 2018by the trend analysis,abrupt change test, R/S analysis and wavelet analysis method. The resultsshow that: The annual average temperature of the study area rises obviously, with the risingtendency rate of about 0.229 ℃/(10a), the abrupt change point of annual average temperature isaround 1997, and the temperature increase trend is more significant after 1999. …”
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Study on the Water Volume of Erhai Lake in Yunnan Plateau by LI Hongyan

“…Based on the monitoring results of hydrological factors such as measured discharge,precipitation,evaporation and outflow in the Erhai Lake Basin from 1956 to 2018,this paper calculates the natural water volume of the Erhai Lake by using two related methods,namely the principle of watershed generation and convergence and the water balance,and studies the trend and periodicity of natural water volume in Erhai Lake over the years through the Manner-Kendall method and wavelet analysis method.The results show that:The natural water volume calculated by the two methods in Erhai Lake for many years is relatively close,with the relative error of 0.5%,that is 851.9 million cubic meters,among which the water production in the lake area is -93.2 million cubic meters,and the water volume of the land is 944.9 million cubic meters (north (a)>west (b)>southeast (c)>east (d),accounting for 54.9%,33.2%,6.9%,and 4.9% of the land water volume,respectively);The natural water volume in the Erhai Lake throughout the year,the flood season,and the dry season show a decreasing trend with time,especially in the flood season;There are periodic changes in the water volume around 9,12,21,and 32 a,which led to the trend of rich and dry changes in the natural water volume of Erhai Lake.…”
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Characteristic Analysis and Prediction of Rainfall and Runoff in Ankang Section of Hanjiang River Basin by LIU Yiwen, LI Jiake, DING Qiang, HAO Gairui

“…Accurate runoff simulation plays a very important role in the planning and management of water resources.However,traditional methods have some limitations in the simulation of runoff near peaks and abrupt points.This paper identifies the abrupt change components of rainfall and runoff in the basins above the controlled section of Ankang Hydrological Station in the Hanjiang River Basin through the Mann-Kendall test.analyzes the trend and cycle of the rainfall and runoff by R/S analysis and wavelet analysis,simulates the runoff series with the partial least squares regression (PLSR) and BP neural network-partial least squares regression (BP-PLSR),and analyzes the simulation effect of runoff near peaks and abrupt points.The results show that:The abrupt points of rainfall appear in 1973,1984 and 2002;and those of runoff appear in 1977 and 1985.The Hurst index of rainfall and runoff is close to 0,indicating that there will be an anti-continuous trend in the future.The simulation effect of BP-PLSR on runoff (RMSE=92.863,NSE=0.797) is better than PLSR (RMSE=152.182,NSE=0.456),and preprocessing the original data by BP can better avoid the over-fitting and local optimization near the abrupt points.…”
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Analysis of Variation Characteristics of Precipitation Series from 1970 to 2019 in Qingyuan City by LIU Xuanxuan

“…In order to understand the variation characteristics of precipitation in Qingyuan City in recent decades,and realize the scientific management and utilization of water resources,based on the measured precipitation data of six representative hydrologic stations in Qingyuan from 1970 to 2019,this paper analyzes and studies the trend change,sudden change and periodic characteristics of annual precipitation in Qingyuan by moving average method,Mann-Kendall test method and Morlet wavelet analysis method.The results show that:The annual precipitation of Qingyuan Station and Zhukeng Station showed a decreasing trend,while that of Damiaoxia Station,Yingde Station,Yangshan Station and Lianxian Station showed an increasing trend,but the change was not significant.The sudden drop occurred around 1975 for Qingyuan Station and Yingde Station,around 2015 for Damiaoxia Station and Lianxian Station,around 1982 for Zhukeng Station.and around 1973 and 2015 for Yangshan Station.The precipitation series of each station has obvious alternation of wet and dry seasons.There are 3 to 4 main periods of precipitation at each station.The first and second main periods are generally 22 or 15 years,and the third and fourth main periods are generally 7 or 3 years.After 2015,the annual precipitation at each station turned into a decreasing trend.Currently,Qingyuan is in a period of low precipitation.…”
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Detection of Lungs Status Using Morphological Complexities of Respiratory Sounds by Ashok Mondal, Parthasarathi Bhattacharya, Goutam Saha

“…The performance of the proposed method is compared with a wavelet analysis based method. The developed algorithm gives a better accuracy of 92.86% and sensitivity of 86.30% and specificity of 86.90% for a composite feature vector of four morphological indices.…”
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Consistency Analysis of Precipitation Characteristics of Mu Us Sandy Land Based on Daily Precipitation Data by MA Lan, LIU Dengfeng, BAI Bing, REN Mengzhi, HUANG Qiang, LIN Mu

“…Mu Us Sandy Land is located in Yulin city of Shaanxi province and Ordos city of Inner Mongolia Autonomous Region,where the ecological and hydrological system is relatively fragile.However,precipitation is an important controlling factor to the evolution of the ecology and hydrology.Meanwhile,the intensity and process of precipitation also have a crucial influence on ecosystem.Therefore,it is necessary to evaluate the consistency of precipitation characteristic value sequences in Mu Us Sandy Land.Based on daily precipitation data from 1957 to 2019 at 10 meteorological stations in Mu Us Sand Land,this paper selects four precipitation characteristic value sequences namely annual precipitation,annual maximum daily precipitation,annual longest continuous precipitation and annual longest continuous precipitation days,and analyzes the trend by Mann-Kendall method,the abrupt change by sliding t test,and the period by continuous wavelet analysis for evaluating the consistency of precipitation characteristic value sequences.The results indicate that:On the whole,the precipitation characteristic value sequences show a decreasing trend;The significant abrupt change points occur in 1970—1990 and after 2000;The main period of the precipitation characteristic value is about 35 years.…”
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Landslide Displacement Prediction Model Based on Time Series and CNN-GRU by FU Zhentao, LI Limin, WANG Lianxia, REN Ruibin, CUI Chengtao, FENG Qingqing

“…Landslide displacement prediction is an important basis for early landslide warning.This paper proposes a prediction model of landslide moving states based on time series and convolutional gated recurrent unit (CNN-GRU) to deal with the shortcomings of previous prediction models.Firstly,after employing wavelet analysis to determine the displacement of the trend term,the exponential smoothing method is adopted to decompose the cumulative displacement to obtain two displacement types of the trend term and the periodic term,and the trend term is fitted by a five-order polynomial.Then,the autocorrelation function is utilized to test the periodic displacement characteristics,and the gray correlation method is applied to determine the correlation degree between each factor and the periodic term.Meanwhile,the periodic term and the influencing factor are input into the CNN-GRU model for prediction,and finally the predicted cumulative displacement value is obtained by superposition.By taking the Baishui River landslide in the Three Gorges Reservoir area as an example,this paper selects the data from January 2004 to December 2012 for study,and the average absolute error percentage of the final prediction results is only 0.525%,with RMSE of 9.614 and R² of 0.993.Experimental results show that CNN-GRU has higher prediction accuracy.…”
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Spectral Analysis of the Svalbard Temperature Record 1912–2010 by Ole Humlum, Jan-Erik Solheim, Kjell Stordahl

“…By means of Fourier and wavelet analysis the record is decomposed into time-frequency space, to extract information on periodic signals and their amplitude and variation over time. …”
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