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RISS 인기검색어
- 검색키워드
- 저자 : Heng-Ming Tai (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Estimation of the Number of Sources Based on Hypothesis Testing
Xiao, Manlin,Wei, Ping,Tai, Heng-Ming The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.5
Accurate and efficient estimation of the number of sources is critical for providing the parameter of targets in problems of array signal processing and blind source separation among other such problems. When conventional estimators work in unfavorable scenarios, e.g., at low signal-to-noise ratio (SNR), with a small number of snapshots, or for sources with a different strength, it is challenging to maintain good performance. In this paper, the detection limit of the minimum description length (MDL) estimator and the signal strength required for reliable detection are first discussed. Though a comparison, we analyze the reason that performances of classical estimators deteriorate completely in unfavorable scenarios. After discussing the limiting distribution of eigenvalues of the sample covariance matrix, we propose a new approach for estimating the number of sources which is based on a sequential hypothesis test. The new estimator performs better in unfavorable scenarios and is consistent in the traditional asymptotic sense. Finally, numerical evaluations indicate that the proposed estimator performs well when compared with other traditional estimators at low SNR and in the finite sample size case, especially when weak signals are superimposed on the strong signals.
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Estimation of the Number of Sources Based on Hypothesis Testing
Manlin Xiao,Ping Wei,Heng-Ming Tai 한국통신학회 2012 Journal of communications and networks Vol.14 No.5
Accurate and efficient estimation of the number of sources is critical for providing the parameter of targets in problems of array signal processing and blind source separation among other such problems. When conventional estimators work in unfavorable scenarios, e.g., at low signal-to-noise ratio (SNR), with a small number of snapshots, or for sources with a different strength,it is challenging to maintain good performance. In this paper, the detection limit of theminimumdescription length (MDL) estimator and the signal strength required for reliable detection are first discussed. Though a comparison, we analyze the reason that performances of classical estimators deteriorate completely in unfavorable scenarios. After discussing the limiting distribution of eigenvalues of the sample covariance matrix, we propose a new approach for estimating the number of sources which is based on a sequential hypothesis test. The new estimator performs better in unfavorable scenarios and is consistent in the traditional asymptotic sense. Finally,numerical evaluations indicate that the proposed estimator performs well when compared with other traditional estimators at low SNR and in the finite sample size case, especially when weak signals are superimposed on the strong signals.
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Wang, Guoning,Du, Xiong,Shi, Ying,Tai, Heng-Ming,Ji, Yongliang The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3
Frequency coupling in the phase domain is a recently reported phenomenon for phase locked loop (PLL) based three-phase grid-inverter systems. This paper investigates the mechanism and stabilization method for the frequency coupling to the stability of grid-inverter systems. Self and accompanying admittance models are employed to represent the frequency coupling characteristics of the inverter, and a small signal equivalent circuit of a grid-inverter system is set up to reveal the mechanism of the frequency coupling to the system stability. The analysis reveals that the equivalent inverter admittance is changed due to the frequency coupling of the inverter, and the system stability is affected. In the end, retuning the bandwidth of the phase locked loop is presented to stabilize the three-phase grid-inverter system. Experimental results are given to verify the analysis and the stabilization scheme.
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Guoning Wang,Xiong Du,Ying Shi,Heng-Ming Tai,Yongliang Ji 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3
Frequency coupling in the phase domain is a recently reported phenomenon for phase locked loop (PLL) based three-phase grid-inverter systems. This paper investigates the mechanism and stabilization method for the frequency coupling to the stability of grid-inverter systems. Self and accompanying admittance models are employed to represent the frequency coupling characteristics of the inverter, and a small signal equivalent circuit of a grid-inverter system is set up to reveal the mechanism of the frequency coupling to the system stability. The analysis reveals that the equivalent inverter admittance is changed due to the frequency coupling of the inverter, and the system stability is affected. In the end, retuning the bandwidth of the phase locked loop is presented to stabilize the three-phase grid-inverter system. Experimental results are given to verify the analysis and the stabilization scheme.
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