변곡점 검출에 기반한 음성의 기본 주파수 추정

임병관 한국전기전자학회 2023 전기전자학회논문지 Vol.27 No.4

피치 혹은 기본 주파수는 음성 신호의 주요 특성 인자이며 음성 부호화, 음성인식, 화자인식 등의 다양한 음성 관련 응용에 활용된다. 본 논문에서는 기본 주파수의 역수인 음성의 피치 주기를 추정하기 위해서 음성 신호의 변곡점을 이용한다. 변곡점은 국소적인 최대값, 최소값 혹은 신호의 기울기가 변하는 지점으로 정의된다. 음성 신호는 저역통과 필터로 먼저 전처리되어 고주파 성분이제거된다. 이를 통해 불필요한 변곡점들이 제거되며, 피치 주기 추정에 유용한 국소적인 최대값만을 변곡점 검출법을 이용하여 추출한다. 얻어진 변곡점 간의 시간 간격을 측정하여 피치 주기를 추정하며, 그 역수로 기본 주파수 추정치를 얻는다. 기존의 피치 추정방법은 음성이 국소적으로 시불변이라는 가정하에 음성을 블록 단위로 처리하여 블록당 피치 주기를 구하지만, 제안된 방법은 음성을 샘플 단위로 처리하여 변곡점을 검출하며, 그 결과 피치 주기를 시간 경과에 따라 얻게 되어 음성의 시변성이 반영된 기본 주파수 추정치를 얻는다. 컴퓨터 모의실험으로 기본 주파수 추정기로서 제안된 방법의 유용성을 볼 수 있다. designed for MMC capacitor voltage estimation. Our observer harnesses the power of a multi-layer neural network

청색 활성제의 첨가 형상 변화에 따른 백색 OLED의 발광 특성

임병관,서정현,백경갑,주성후,Lim, Byung-Gwan,Seo, Jung-Hyun,Paek, Kyeong-Kap,Ju, Sung-Hoo 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.6

To investigate the effect of two-emission-layer structure on the emission characteristics of the phosphorescent white organic light-emitting diodes (PHWOLEDs), the PHWOLEDs with two different emission layers, blue EML(29 nm, FIrpic-doped mCP) and red EML(1 nm, Ir(pq)$_2$acac-doped CBP)), following host-guest system were fabricated. The bi-layered blue EML was composed of mCP:FIrpic (20 nm, 7 vol.%) and mCP:FIrpic (9 nm, 7, 10, 15, 20, and 25 vol.%, respectively). When the concentration of FIrpic was increased from 7 to 15 vol.%, light emission luminance, current efficiency, and external quantum efficiency were increased. On the contrary, when the concentration of FIrpic was increased to more than 20 vol.%, light emission luminance, current efficiency, and external quantum efficiency were decreased. The PHWOLEDs with the bi-layered blue EML structure of mCP:FIrpic (20 nm, 7 vol.%) and mCP:FIrpic (9 nm, 15 vol.%) showed current efficiency of 29.7 cd/A and external quantum efficiency (EQE) of 16.6% at 1,000 $cd/cm^2$.

수필 : 사랑하는 딸에게

임병관 대한토목학회 1995 대한토목학회지 Vol.43 No.4

고령의 연령에서 굴절이상과 안광학 성분들의 연관성 분석

임병관,전순우,정연홍 한국안광학회 2011 한국안광학회지 Vol.16 No.3

Purpose: This study was to know the correlation among refractive error and the dimensions of ocular components on older adults. Methods: The subjects were 95 older age who had no eye diseases. The refractive error, corneal radius, corneal diopter, axial length, anterior chamber depth and lens thickness were measured and analysed. Results: The axial length(AL)/corneal radius(CR) ratio was positively correlated with the corneal diopter, axial length, the anterior chamber depth. Then it was negatively correlated with corneal radius. It was shown that the highest correlation was between the corneal diopter and axial length (r=-0.545, p=0.000). The spherical equivalent of the refractive error was negatively correlated with the AL/CR ratio. Conclusions: It was shown that the AL/CR ratio was a very important indicator for diagnosing the refractive error of the old age.

정공수송층에 따른 백색 OLED의 발광 특성

임병관,서정현,주성후,백경갑,Lim, Byung-Gwan,Seo, Jung-Hyun,Ju, Sung-Hoo,Paek, Kyeong-Kap 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.12

In order to investigate the emission characteristics of the phosphorescent white organic light-emitting diodes (PHWOLEDs) according to various hole transport layers (HTLs), PHWOLEDs composed of HTLs whose structure are NPB/TCTA, NPB/mCP and NPB/TCTA/mCP, two emissive layers (EMLs) which emit two-wavelengths of light (blue and red), and electron transport layer were fabricated. The applied voltage, power efficiency, and external quantum efficiency at a current density of $1 mA/cm^2$ for the fabricated PHWOLEDs were 7.5 V, 11.5 lm/W, and 15%, in case of NPB/mCP, 5 V, 14.8 lm/W, and 13.7%, in case of NPB/TCTA, and 5.5 V, 14.6 lm/W, and 15%, in case of NPB/TCTA/mCP in the hole transport layer, respectively. High emission efficiency can be obtained when the amount of hole injection from anode is balanced out by the amount of electron injection from the cathode to EML by using NPB/TCTA/mCP structured HTL.

A Low Bit Rate Speech Coder Based on the Inflection Point Detection

임병관 한국지능시스템학회 2015 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.15 No.4

A low bit rate speech coder based on the non-uniform sampling technique is proposed. The non-uniform sampling technique is based on the detection of inflection points (IP). A speech block is processed by the IP detector, and the detected IP pattern is compared with entries of the IP database. The address of the closest member of the database is transmitted with the energy of the speech block. In the receiver, the decoder reconstructs the speech block using the received address and the energy information of the block. As results, the coder shows fixed data rate contrary to the existing speech coders based on the non-uniform sampling. Through computer simulation, the usefulness of the proposed technique is shown. The SNR performance of the proposed method is approximately 5.27 dB with the data rate of 1.5 kbps.

시주파수 분석법을 이용한 음성의 기본주파수 검출

임병관 대한전기학회 2006 전기학회논문지 D Vol.55 No.1(D)

- A simple robust fundamental frequency estimator on the time-frequency domain is proposed. Combined with the appropriately designed low-pass filter, the instantaneous frequency estimator based on the Teager-Kaiser energy function can detect the fundamental frequency of speech signal. The Teager-Kaiser function can be obtained through real computation and show the change of frequency as time goes. And when a speech block with N samples is processed with a lowpass filter with length of L, it requires operations, compared to operations in the recently introduced wavelet and conventional instantaneous frequency method. The computer simulation confirms the usefulness of the proposed fundamental frequency estimation method.

Generalized Higher Order Energy Based Instantaneous Amplitude and Frequency Estimation and Their Applications to Power Disturbance Detection

임병관 한국지능시스템학회 2012 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.12 No.2

The instantaneous amplitude (IA) based on the higher order differential energy operator is proposed. And its general form for arbitrary order is also proposed. The various definitions of the IA and the instantaneous frequency (IF) estimators are considered. The IA and IF estimators based on the energy operators need less computational cost than the conventional IF and IA estimators exploiting the Hilbert transform. The IF and IA estimators are compared in terms of the frequency and amplitude tracking accuracy of the AM-FM signals. For noiseless case, the IA and IF estimators based on the Teager-Kaiser energy operator show better tracking performance than the IF and IA estimators based on the higher energy operators. However, under noisy condition, the IF and IA estimator based on the higher order energy operators with the order 3 and 4 show better tracking than the Teager-Kaiser energy based estimators. The IF and IA estimators are applied to signals in the various power anomalies to show their usefulness as the disturbance detectors.

연령별·직업별 누진굴절력 렌즈 안경의 착용 적응도에 대한 조사

임병관,박수봉,이혜정,김대현,선경호,정연홍 대한시과학회 2006 대한시과학회지 Vol.8 No.2

본 조사에서는 안질환이 없는 남녀 130명(남자 63명, 여자 67 명)을 대상으로 누진 렌즈 처방이 가능한 40세 이상의 환자를 굴절이상도와 근용 가입도를 측정하여 연령 별 · 직업별 누진굴절력 렌즈 안경의 착용 적응도를 조사하였다. 조사대상자들의 굴절 상태 분포는 정시자 35 명 (26.9%) , 근시자 28명 (21.5%) , 원시자 33 명 (25.4%), 혼합난시 30명 (23.1%), 기 타 4 명 (3 .1%)으로 나타났으며 , 근용 가입 도의 분포를 보면 +1.00D 미 만이 4명 (3.1%), +1.00-+ 1.50D는 44병 (33.8%), +1.75-+2.25D가 42명 (32.3%), +2.50- +3.00D는 40 명 (30.8%) 으로 조사되 었다. 누진 렌즈를 처 방받은 환자들의 착용 적 응도 조사결과는 10 일 미 만이 32 명 (24.6%), 10-20 일 미만이 52 명 (40.0%) , 20-30 일 미만이 23 명(17.7%) , 30-40 일 미만이 15명 (11.5%) 그리 고 적 응실 패 는 8명 (6.2%)으로 나타났다. 직 업 별 착용 적 응도는 20 일 미 만까지 목사 100.0%, 교육직 78.6%, 예술가 85.7%, 사무직 64.6%, 주부 48.5%로 조사 되었으며 적응실패자도 6.2%로 나타났다 This research had been investigated for adaptation to wear progressive additional lenses according to age and occupation in 130 healthy Korean with presbyopia over age 40. The rate of the presbyopes prescribed progressÍve additional lenses by classification of refraction: 21.5% of myopia, 26.9% of emmetropia, 25.4% of hyperopia, 23.1% of mixed astigmatism, 3.1% of others. The rate of the presbyopes prescribed progressive additional lenses according to range of addition: 3.10% of under + 1.00D, 33.8% of + 1.00D - + 1.50D, 32.3% of + 1.75D - +2.25D, 30.8% of +2.50D -+3.00D. The rate of adaptation to wear progressive additional lenses prescribed presbyopes : 24.6% of under 10 days, 40% of 10-20 days, 17.7% of 20-30 days, 11.5% of 30 -40 days, 6.20% of failure of adaptation. Distribution accoding to occupation in adaptation of the presbyopes prescribed progressive addition lenses with in 20days Minister 100.0%, Teacher 78.6%, Artist 85.7%, Office work 64.6%, Housewife 48.5%.

Myocardial injury occurs earlier than myocardial inflammation in acute experimental viral myocarditis

임병관,신재옥,최성준,최시완,정진옥,성인환,김덕경,전은석 생화학분자생물학회 2005 Experimental and molecular medicine Vol.37 No.1

Endomyocardial biopsy often fails to show myo-suspected myocarditis. The serum isoforms of troponin T (cTnT) level is a very sensitive mar-ker of myocardial injury and it is elevated even in the absence of myocardial inflamation. We investigated the corelations for myocardial in-jury, virus titers and inflammation in acute viral infection. Using the murine coxsackievirus group B3 (CVB3) myocarditis model, the histopatho-logic findings and virus titers in mouse hearts were compared with the serum cTnT levels mea-sured by ELISA at various time points. Viable infection (8.220.13 log10 PFU/100 mg of heart); they decreased at day 7 and no viable virus was detected from day 14. Myocardial inflamation was minimal at day 3, peaked at day 7 and markedly decreased at day 14. The individual serum TnT levels were significantly increased at day 3 (7.371.46 ng/ml), persisted to day 7 (0.73 0.08 ng/ml), and normalized at day 14. Serum cTnT levels were corelatable with virus titers in the heart (r= 0.744, P< 0.01), with the degrees of inflammation. Using the less myocarditic strain of CVB3, similar relationships were observed between the changes for the serum cTnT levels and the heart virus titers. During the course of viral infection, myocardial injury precedes the pathologic evidence of in-flamation, and the elevated cTnT levels pro-vide evidence of myocardial injury even in the absence of any histologic findings of myocarditis.