Study on mechanism and filter efficacy of AGO/IAGO in the frequency domain
Grey Systems: Theory and Application
ISSN: 2043-9377
Article publication date: 26 May 2020
Issue publication date: 13 January 2021
Abstract
Purpose
The purpose of this paper is to analyze the mechanism and filter efficacy of accumulation generation operator (AGO)/inverse accumulation generation operator (IAGO) in the frequency domain.
Design/methodology/approach
The AGO/IAGO in time domain will be transferred to the frequency domain by the Fourier transform. Based on the consistency of the mathematical expressions of the AGO/IAGO in the gray system and the digital filter in digital signal processing, the equivalent filter model of the AGO/IAGO is established. The unique methods in digital signal processing systems “spectrum analysis” of AGO/IAGO are carried out in the frequency domain.
Findings
Through the theoretical study and practical example, benefit of spectrum analysis is explained, and the mechanism and filter efficacy of AGO/IAGO are quantitatively analyzed. The study indicated that the AGO is particularly suitable to act on the system's behavior time series in which the long period parts is the main factor. The acted sequence has good effect of noise immunity.
Practical implications
The AGO/IAGO has a wonderful effect on the processing of some statistical data, e.g. most of the statistical data related to economic growth, crop production, climate and atmospheric changes are mainly affected by long period factors (i.e. low-frequency data), and most of the disturbances are short-period factors (high-frequency data). After processing by the 1-AGO, its high frequency content is suppressed, and its low frequency content is amplified. In terms of information theory, this two-way effect improves the signal-to-noise ratio greatly and reduces the proportion of noise/interference in the new sequence. Based on 1-AGO acting, the information mining and extrapolation prediction will have a good effect.
Originality/value
The authors find that 1-AGO has a wonderful effect on the processing of data sequence. When the 1-AGO acts on a data sequence X, its low-pass filtering effect will benefit the information fluctuations removing and high-frequency noise/interference reduction, so the data shows a clear exponential change trends. However, it is not suitable for excessive use because its equivalent filter has poles at the non-periodic content. But, because of pol effect at zero frequency, the 1-AGO will greatly amplify the low-frequency information parts and suppress the high-frequency parts in the information at the same time.
Keywords
Acknowledgements
This work was supported by a project of the National Natural Science Foundation of China entitled “Research on network of reliability growth of complex equipment under the background of collaborative development” (71671091). It is also supported by a joint project of both the NSFC and the RS of the UK entitled “On grey dynamic scheduling model of complex product based on sensing information of Internet of things” (71811530338), a project of the Leverhulme Trust International Network entitled “Grey Systems and Its Applications” (IN-2014–020). At the same time, the authors would like to acknowledge the partial support of the Fundamental Research Funds for the Central Universities of China (NC2019003) and support of a project of Intelligence Introduction Base of the Ministry of Science and Technology (G20190010178).
Citation
Lin, C., Song, Z., Liu, S., Yang, Y. and Forrest, J. (2021), "Study on mechanism and filter efficacy of AGO/IAGO in the frequency domain", Grey Systems: Theory and Application, Vol. 11 No. 1, pp. 1-21. https://doi.org/10.1108/GS-01-2020-0014
Publisher
:Emerald Publishing Limited
Copyright © 2020, Emerald Publishing Limited