• ETRI Journal
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• 제37권4호
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• pp.780-786
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• 2015

This paper describes an audio source separation that is based on nonnegative matrix factorization (NMF) and expectation maximization (EM). For stable and highperformance separation, an effective auxiliary source separation that extracts source residuals and reprojects them onto proper sources is proposed by taking into account an ambiguous region among sources and a source's refinement. Specifically, an additional NMF (model) is designed for the ambiguous region - whose elements are not easily represented by any existing or predefined NMFs of the sources. The residual signal can be extracted by inserting the aforementioned model into the NMF-EM-based audio separation. Then, it is refined by the weighted parameters of the separation and reprojected onto the separated sources. Experimental results demonstrate that the proposed scheme (outlined above) is more stable and outperforms existing algorithms by, on average, 4.4 dB in terms of the source distortion ratio.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.105-139
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• 2005

Increased signal in T1-weighted images was observed in the experimental manganese (Mn) poisoning of the non-human primate and a patient with Mn neurointoxication. However, our study showed that the increased signals in magnetic resonance images (MRI) were highly prevalent (41.6%) in Mn-exposed workers. Blood Mn concentration correlated with pallidal index. These changes in MRI tend to disappear following the withdrawal from the source of Mn accumulation, despite permanent neurological damage. Thus increased signal intensities on a T1-weighted image reflect exposure to Mn, but not necessarily manganism. Our study also showed that the concentration of Mn required to produce increased signal intensities on MRI is much lower than the threshold necessary to result in overt clinical signs of manganism. Increased signal intensities in the globus pallidus were determined by manganese accumulation in the animal experiment. Reanalysis of the previous data with the structural equation model revealed that pallidal index (Pl) on MRI reflects target organ dose of occupational Mn exposure

• 한국지역지리학회지
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• 제10권2호
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• pp.389-406
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• 2004

최근 지역 연구의 활성화와 더불어 지역 자료의 중요성이 점점 강조되고 있다. 그런데 실제 이용가능한 지역 자료의 공간단위는 연구 분석을 위한 기능지역 단위와 일치하지 않는 경우가 종종 발생하며, 이로 인해 발생하는 문제를 해결하기 위해 이용가능한 지역 단위 자료를 연구 분석을 위한 공간 단위로 재구성하는 방법이 요구된다. 본 연구는 면적 가중치 내삽법, pycnophylactic 방법, dasymetric 방법, Area-to-point 내삽법 등을 검토하고 도시지역 자료의 효율적인 재구성 방법으로 면적 가중치 내삽법을 수정하여 인구 가중치 내삽법(population weighted interpolation)을 제안하였다. 인구 가중치 내삽법은 미국 뉴욕주 이리 카운티(Erie County)를 연구 사례로 면적 가중치 방법 pycnophylactic 방법을 RMS 에러, 자료 분포 유형, 공간 자기상관의 측면에서 비교되었다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.893-898
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• 1994

In this paper, the influence of voice source estimation and modeling on speech synthesis and coding is examined and then their new estimation and modeling techniques are proposed and verified by computer simulation. It is known that the existing speech synthesizer produced the speech which is dull and inanimated. These problems are arised from the fact that existing estimation and modeling techniques can not give more accurate voice parameters. Therefore, in this paper we propose a new voice source estimation algorithm and modeling techniques which can not give more accurate voice parameters. Therefore, in this paper we propose a new voice source estimation algorithm and modeling techniques which can represent a variety of source characteristics. First, we divide speech samples in one pitch region into four parts having different characteristics. Second, the vocal-tract parameters and voice source waveforms are estimated in each regions differently using sequential SVD. Third, we propose composite source model as a new voice source model which is represented by weighted sum of pre-defined basis functions. And finally, the weights and time-shift parameters of the proposed composite source model are estimeted uning EM(estimate maximize) algorithm. Experimental results indicate that the proposed estimation and modeling methods can estimate more accurate voice source waveforms and represent various source characteristics.

• 한국환경보건학회지
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• 제33권5호
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• pp.359-364
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• 2007

The aim of this study were to assess the personal exposure to volatile organic compounds (VOCs) and to estimate the personal exposure using time-weighted average model. Three target VOCs (benzene, toluene, xylene) were analyzed in personal exposure samples and residential indoor, residential outdoor and workplace indoor microenvironments samples in the iron mill 30 workers during working 5 days. Personal exposure to VOCs significantly correlated with workplace concentration p<0.05), suggesting workplace had strong source and major contribution to personal exposure. Personal exposure could be estimated with time activity pattern and time weighted average (TWA) model of residential indoor and workplace concentrations measured. Time weighted mean microenvironments concentrations were close approximately of personal exposure concentrations. Total exposure for participants can be estimated by TWA with microenvironments measurements and time activity pattern.

• Nuclear Engineering and Technology
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• 제46권2호
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• pp.273-280
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• 2014

The spectrum weighted responses of various detectors were calculated to provide guidance on the proper selection and use of survey instruments on the basis of their energy response characteristics on the neutron fields. To yield the spectrum weighted response, the detector response functions of 17 neutron-measuring devices were numerically folded with each of the produced calibration neutron spectra through the in-house developed software 'K-SWR'. The detectors' response functions were taken from the IAEA Technical Reports Series No. 403 (TRS-403). The reference neutron fields of 21 kinds with 2 spectra groups with different proportions of thermal and fast neutrons have been produced using neutrons from the $^{241}Am$-Be sources held in a graphite pile, a bare $^{241}Am$-Be source, and a DT neutron generator. Fluence-average energy ($E_{ave}$) varied from 3.8 MeV to 16.9 MeV, and the ambient-dose-equivalent rate [$H^*(10)/h$] varied from 0.99 to 16.5 mSv/h.

• Journal of Information Processing Systems
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• 제12권2호
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• pp.322-331
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• 2016

Image compression is an essential technique for saving time and storage space for the gigantic amount of data generated by images. This paper introduces an adaptive source-mapping scheme that greatly improves bit-level lossless grayscale image compression. In the proposed mapping scheme, the frequency of occurrence of each symbol in the original image is computed. According to their corresponding frequencies, these symbols are sorted in descending order. Based on this order, each symbol is replaced by an 8-bit weighted fixed-length code. This replacement will generate an equivalent binary source with an increased length of successive identical symbols (0s or 1s). Different experiments using Lempel-Ziv lossless image compression algorithms have been conducted on the generated binary source. Results show that the newly proposed mapping scheme achieves some dramatic improvements in regards to compression ratios.

• 한국수자원학회논문집
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• 제46권2호
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• pp.139-153
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• 2013

고르지 않은 바닥을 지나는 천수 흐름을 해석하기 위해 천수방정식의 흐름률 경사항과 바닥 경사 생성항에 대해 HLLL 기법과 DFB(Divergence Form for Bed slope source term) 기법을 각각 적용하여 유한체적 모형을 구성하였다. 또한, PSC(Partially Submerged Cell)의 고려를 위해 VFR(Volume/Free-surface Relationship)도 이용하였다. MUSCL에서 WSDGM(Weighted Surface-Depth Gradient Method)을 보다 단순하게 고쳐도 원래의 방법과 정확도가 동등함을 1차원 정상 흐름에 대해 확인하였다. 1차원 PSC에 대한 VFR를 통해 흐름률 경사항과 바닥 경사 생성항의 선평형성이 정확하게 충족됨을 입증하였다. 2차원 PSC에서 DFB 기법으로는 지배방정식의 선평형성이 충족되지 않은 문제를 삼각형 격자에 대한 VFR를 이용하여 해소하였다. 삼각형 턱과 둥근 융기를 지나는 2차원 댐 붕괴 흐름에 대한 모의에서 실험실 실험 결과와 잘 부합됨을 확인하였다. 또한, 부분 댐 붕괴 흐름에 대한 모형의 적용에서 경사면은 물론 불규칙 바닥에서도 요철의 잠김이 성공적으로 모의되었다. 따라서 고르지 않은 실제 하천 지형에 대한 이 모형의 적용성이 기대된다.

• 대한전기학회논문지
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• 제39권6호
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• pp.545-556
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• 1990

A design method of a current source using 12-pulse phase-controlled rectifier (PCR) is presented. The critical inductance of the 12-pulse PCR is derived and it is shown that the critical inductance can be reduced using a current source. The control circuit of the 12-pulse PCR with an inner fast dynamic loop is proposed to give the frequency synchronism and to reduce the subharmonics due to the unbalance of the transformer of the power line. This circuit is analyzed and its dynamic loop is optimized. The optimal constant PIMF (proportional, integral and measurable variable feedback, and feedforware) controller is also designed using the time-weighted quadratic performance index. It is shown via experimental results that the proposed design method gives high dynamic and static performance of the current source using the 12-pulse PCR.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.727-734
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• 2008

This research presents a laboratory study about difference of subjective response between with and without pictures. A main source is impulsive sound caused by leisure shooting. The sources are sampled from outdoor noise and their levels range from 40 to 75 dB at the interval of 5dB. The noise unit is based on A-weighted sound exposure level (ASEL; $L_{AE}$). To make equal ASEL of outdoor noise, finite impulse response (FIR) filter is applied to the originally sampled source to include the effect of distance attenuation. The evaluation method of the jury test adopted a Semantic Difference(SD) Method. The intersection point which two lines crossed was used as reference point. The intersecting point of mean response rating between with and without pictures was approximately 44ASEL and that of %HA was about 60ASEL. In the result of the test, the negative effect of pictures was given at a lower levels than intersection point while the positive effect was given at a higher levels than that.