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주파수 대역별 잔향시간 추정을 위한 변형된 AWSSDR 방식
김민식,김형순 한국음성학회 2023 말소리와 음성과학 Vol.15 No.4
Reverberation time (T60) is a typical acoustic parameter that provides information about reverberation. Since the impacts of reverberation vary depending on the frequency bands even in the same space, frequency-dependent (FD) T60, which offers detailed insights into the acoustic environments, can be useful. However, most conventional blind T60 estimation methods, which estimate the T60 from speech signals, focus on fullband T60 estimation, and a few blind FDT60 estimation methods commonly show poor performance in the low-frequency bands. This paper introduces a modified approach based on Attentive pooling based Weighted Sum of Spectral Decay Rates (AWSSDR), previously proposed for blind T60 estimation, by extending its target from fullband T60 to FDT60. The experimental results show that the proposed method outperforms conventional blind FDT60 estimation methods on the acoustic characterization of environments (ACE) challenge evaluation dataset. Notably, it consistently exhibits excellent estimation performance in all frequency bands. This demonstrates that the mechanism of the AWSSDR method is valuable for blind FDT60 estimation because it reflects the FD variations in the impact of reverberation, aggregating information about FDT60 from the speech signal by processing the spectral decay rates associated with the physical properties of reverberation in each frequency band.
임도개설(林道開設)이 산지급류소하천(山地急流小河川)의 전기전도도(電氣傳導度)와 이온농도(濃度)에 미치는 영향 - 임도개설지(林道開設地)와 미개설지(未開設地) 비교(比較) -
김민식,전근우,에자키 츠기오,Kim, Min-Sik,Chun, Kun-Woo,Ezaki, Tsugio 강원대학교 산림과학연구소 1997 Journal of Forest Science Vol.13 No.-
This study examined the effect of forest road construction on electronic conductivity(EC) and ion concentrations under different precipitation. They were torrential streams within three different watersheds with various forest road densities (watershed A : 8.82m/ha, watershed B: 2.32m/ha, and watershed C: control) in the Experimental Forest of Kangwon National University. The results were as follows: 1. EC of three watersheds did not show on difference in precipitation, but it was high in case of long interval rainfall time period. EC of watershed A and B were higher than that of watershed C. 2. Concentrations of cation was about 2 times higher than those of anion. Average concentrations of $N^+$ and $Ca^{2+}$ showed maximum and minimum respectively, and $SO_4{^{2-}}$ was 3.7 times higher than $Cl^-$. 3. Precipitation and discharge had no effect on ion concentrations, but watershed A and B were higher in concentrations of cation than watershed C. 강원대학교(江原大學校) 산림과학대학(山林科學大學) 부속연습림내(附屬演習林內)의 임도밀도가 상이한 세 유역(유역 A: 8.82m/ha, B: 2.32m/ha 및 C: 미개설(未開設))의 산지급류소하천(山地急流小河川)을 대상으로 1995년, 1996년의 강우량(降雨量) 및 유출량(流出量)에 따른 전기전도도와 이온농도를 분석한 결과는 다음과 같다. 1. 전기전도도는 강우량에 따라 크게 변화하지 않았으나 대체로 전강우(前降雨)와 간격이 긴 경우가 높게 나타났으며, 임도개설유역이 미개설유역보다 높게 나타났다. 2. 이온성분별 농도는 음이온이 양이온보다 약 2배이상 유출되었다. 이온별 평균농도는 양이온의 경우 $Na^+$과 $Ca^{2+}$이 각각 최대 및 최소로 나타났으며, 음이온의 경우는 $SO_4{^{2-}}$가 $Cl^-$보다 3.7배 이상 높게 나타냈다. 3. 총이온농도는 강우량과 유출량에 민감하게 반응하지는 않았으나 양이온의 경우 임도개설지가 미개설지보다 높게 나타났다.