Spatiotemporal analysis of the groundwater head variation caused by natural stimuli using independent component analysis and continuous wavelet transform

Tsai, Jui-Pin; Hsiao, Chin-Tsai

doi:10.1016/j.jhydrol.2020.125405

Cited by 10 publications

(4 citation statements)

References 24 publications

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“…The core idea of distributed hash algorithm is to get Hash Key according to the specialty of storage object (key) by operation of Hash and the distributed storage processes according to the Hash Key. In case of no need to the server, each user shall be responsible for a small scale route, and storing a small part of data in order to realize the addressing and storage of the whole DHT network 5 .…”

Section: Dhtmentioning

confidence: 99%

A P2P VoIP system based on Kademlia protocol

Cui

2022

6th International Conference on Mechatronics and Intelligent Robotics (ICMIR2022)

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Currently, there are two hot issues on the research of Internet application technology, which are peer to peer (P2P) and Voice over IP (VoIP) based on IP technologies respectively. Recently, there is a trend that the technology of P2PVoIP is integrated by the above 2 technologies. The essay based on the defect of traditional VoIP system discusses on the future development trend of VoIP system and purposes a pure P2P VoIP structure based on Kademlia system. Finally a P2P VoIP system-ppPhone is designed and completed.

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Section: Dhtmentioning

confidence: 99%

A P2P VoIP system based on Kademlia protocol

Cui

2022

6th International Conference on Mechatronics and Intelligent Robotics (ICMIR2022)

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“…The positive and negative changes in contour of the real part of the coefficient represent the evolution process and abrupt characteristics of the given data in the near future: the positive value corresponds to the rise period of the sequence, the negative value corresponds to the reduction phase, and the zero value corresponds to the transition period. The magnitude of the modulus square of the wavelet coefficient reflects the oscillation strength of the signal at different time scales and the energy distribution at the specific time scale (Tsai and Hsiao 2020). The integral of this value with scale factor a is called the wavelet variance function。Variance diagram can further determine the main period in time series (Partal 2017).…”

Section: Wavelet Analysismentioning

confidence: 99%

Characteristics in the Spatiotemporal Variation and Periodic Evolution of Groundwater in the Xining Area of China, Eastern Qinghai–Tibet Plateau

Li¹,

Zhan²,

Lu³

et al. 2021

Preprint

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Groundwater, an important source of water, has profound effects on global human survival and production. The spatiotemporal characteristics of groundwater and the periodic variation law of different time scales must be analyzed to grasp the dynamic situation of groundwater and provide scientific guidance for the rational utilization and management of groundwater resources. In this study, the temporal and spatial variability and periodicity of groundwater level were studied in the Xining region of the eastern Qinghai–Tibet Plateau China using traditional statistical method, geographic information system and Morlet wavelet analysis. Results show that the groundwater dynamics in the study area are mainly controlled by three factors, namely, the amount of river water infiltration, discharge from the groundwater, and artificial exploitation. The aforementioned factors can be divided into three dynamic types according to their combination relationship: hydrological, hydrological exploitation, and runoff-discharge types. The groundwater depth showed a trend of first increasing, then stabilizing, and finally decreasing from 1980 to 2020. The analysis in spatial variability demonstrated that the groundwater depth in different periods has a great spatial difference, with a moderate spatial variation intensity. Moreover, the spatial correlation of groundwater in the abundant season is lower than that in the dry season, which is mainly caused by the strengthening of artificial exploitation. The groundwater depth in the Xining region presents a pattern of deep in the south and east and shallow in the north and west by Kriging interpolation of spherical model in geographic information system. Meanwhile, the inter-annual groundwater has continued to decline since the chronic overexploitation between the 1960s and 2000s, with a maximum cumulative depth of 15 m. Then, the amount extraction had been further reduced, and rainfall had significantly increased in recent years. Accordingly, the cone of depression has undergone an evolutionary process from an expansion period to a stable period to a shrinking period. Furthermore, the annual groundwater level of most monitoring wells in study area has the same multi-year scale time variation characteristics with an evident regular periodic variation on the 9-14a and 17-25a time scales by using Morlet wavelet transform analysis. The temporal sequence of groundwater from 1980 to 2020 has the first and second main periods of 12a and 21a. In accordance with the two time-scales, the groundwater level will continue to rise in the short term in the future, which provides a scientific theoretical basis for the long-term sustainable development of groundwater resources and government decision-making.

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“…The monitoring data of groundwater level depth are continuous and nonstationary time series. Therefore, the complex Morlet continuous wavelet transform is selected as the Springer wavelet function in this study, and the discrete complex wavelet coefficient function is as follows: and the energy distribution at the specific time scale (Tsai and Hsiao 2020). The integral of this value with scale factor a is called the wavelet variance function。Variance diagram can further determine the main period in time series (Partal 2017).…”

Section: Wavelet Analysismentioning

confidence: 99%

Spatiotemporal variation and periodic evolution characteristics of groundwater in the Xining area of China, eastern Qinghai–Tibet Plateau

Zhan

et al. 2021

Environ Earth Sci

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Groundwater, an important source of water, has profound effects on global human survival and production. The spatiotemporal characteristics of groundwater and the periodic variation law of different time scales must be analyzed to grasp the dynamic situation of groundwater and provide scientific guidance for the rational utilization and management of groundwater resources. In this study, the temporal and spatial variability and periodicity of groundwater level were studied in the Xining region of the eastern Qinghai-Tibet Plateau China using traditional statistical method, geographic information system and Morlet wavelet analysis.Results show that the groundwater dynamics in the study area are mainly controlled by three factors, namely, the amount of river water infiltration, discharge from the groundwater, and artificial exploitation. The aforementioned factors can be divided into three dynamic types according to their combination relationship: hydrological, hydrological exploitation, and runoff-discharge types. The groundwater depth showed a trend of first increasing, then stabilizing, and finally decreasing from 1980 to 2020. The analysis in spatial variability demonstrated that the groundwater depth in different periods has a great spatial difference, with a moderate spatial variation intensity. Moreover, the spatial correlation of groundwater in the abundant season is lower than that in the dry season, which is mainly caused by the strengthening of artificial exploitation. The groundwater depth in the Xining region presents a pattern of deep in the south and east and shallow in the north and west by Kriging interpolation of spherical model in geographic information system. Meanwhile, the inter-annual groundwater has continued to decline since the chronic overexploitation between the 1960s and 2000s, with a maximum cumulative depth of 15 m. Then, the amount extraction had been further reduced, and rainfall had significantly increased in recent years.Environmental Earth Sciences (2021) x:x Page 2 of 32 Springer Accordingly, the cone of depression has undergone an evolutionary process from an expansion period to a stable period to a shrinking period. Furthermore, the annual groundwater level of most monitoring wells in study area has the same multi-year scale time variation characteristics with an evident regular periodic variation on the 9-14a and 17-25a time scales by using Morlet wavelet transform analysis. The temporal sequence of groundwater from 1980 to 2020 has the first and second main periods of 12a and 21a. In accordance with the two time-scales, the groundwater level will continue to rise in the short term in the future, which provides a scientific theoretical basis for the long-term sustainable development of groundwater resources and government decision-making.

show abstract

Spatiotemporal analysis of the groundwater head variation caused by natural stimuli using independent component analysis and continuous wavelet transform

Cited by 10 publications

References 24 publications

A P2P VoIP system based on Kademlia protocol

A P2P VoIP system based on Kademlia protocol

Characteristics in the Spatiotemporal Variation and Periodic Evolution of Groundwater in the Xining Area of China, Eastern Qinghai–Tibet Plateau

Spatiotemporal variation and periodic evolution characteristics of groundwater in the Xining area of China, eastern Qinghai–Tibet Plateau

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