http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Chung, Yongjoo,Paik, Chunhyun,Kim, Young Jin Elsevier 2019 International journal of greenhouse gas control Vol.81 No.-
<P><B>Abstract</B></P> <P>It is widely acknowledged that the power generation sector is a major source of greenhouse gas emissions. Especially, carbon dioxide emissions from the coal-fired power plant fleet are estimated to be 8.5 Giga tons in 2010 accounting for one-quarter of the global anthropogenic carbon emissions. It has often been claimed that the power plants retrofit may be considered one of the most promising emissions reduction alternatives. This study presents a noble approach to modeling the power plant retrofit based on the bottom-up formulation of OSeMOSYS, which provides a wide range of flexibility in energy systems modeling. The proposed approach has been demonstrated for the Korean electricity sector. The optimal solutions for the schedule of power plants retrofit have been obtained, and the effect of retrofit options on greenhouse gas emissions and associated costs has been further examined. It is shown that the power plants retrofit can be highly cost-effective for emissions reduction from the power generation sector. The proposed approach to retrofit modeling may contribute to attaining a deeper understanding on the analysis of power plants retrofit.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Modeling approach to power plants retrofit is proposed and the corresponding OSeMOSYS code is also developed. </LI> <LI> The applicability of the proposed approach is demonstrated with coal-fired power plants retrofit of the Korean electricity sector. </LI> <LI> It is shown that power plants retrofit may be considered one of the most promising mitigation measures for the power generation sector. </LI> </UL> </P>
Yongjoo Chung,Hugon Kim 한국경영과학회 2010 Management Science and Financial Engineering Vol.16 No.3
In this study, we present the exact methods of transforming the continuous solutions into the discrete ones for two types of bit?loading problem, marginal adaptive (MA) and rate adaptive (RA) problem, in multicarrier communication systems. While the computational complexity of existing solution methods for discrete optimal solutions depends on the number of bits to be assigned ( R ), the proposed method determined by the number of subcarriers ( N ), making ours be more efficient in most cases where R is much larger than N . Furthermore our methods have some strength of their simpler form to make a practical use.
연속 잡음 음성 인식을 위한 다 모델 기반 인식기의 성능 향상에 대한 연구
정용주(Yongjoo Chung) 한국음성학회 2008 음성과학 Vol.15 No.2
Recently, the multi-model based speech recognizer has been used quite successfully for noisy speech recognition. For the selection of the reference HMM (hidden Markov model) which best matches the noise type and SNR (signal to noise ratio) of the input testing speech, the estimation of the SNR value using the VAD (voice activity detection) algorithm and the classification of the noise type based on the GMM (Gaussian mixture model) have been done separately in the multi-model framework. As the SNR estimation process is vulnerable to errors, we propose an efficient method which can classify simultaneously the SNR values and noise types. The KL (Kullback-Leibler) distance between the single Gaussian distributions for the noise signal during the training and testing is utilized for the classification. The recognition experiments have been done on the Aurora 2 database showing the usefulness of the model compensation method in the multi-model based speech recognizer. We could also see that further performance improvement was achievable by combining the probability density function of the MCT (multi-condition training) with that of the reference HMM compensated by the D-JA (data-driven Jacobian adaptation) in the multi-model based speech recognizer.
한국의 폐기물부문의 온실가스 배출량 및 감축잠재량 분석
정용주(Yongjoo Chung),김후곤(Hugon Kim) 한국경영과학회 2016 經營 科學 Vol.33 No.4
Waste sector has been a target of abatement policies by the most governments, even though its greenhouse gas (GHG) emission is not so high, since it is related to almost of other sectors. This study propose new GHG calculation equations which resolves logical contradiction of IPCC GL (Intergovernmental Panel on Climate Change Guideline) equations by including waste-to-energy effects. According to two GHG calculation equations, GHG emission inventory and BAU by the year 2050 have been computed. And GHG abatement potential and marginal cost for the five abatement policies carefully selected from the previous researches have been calculated for the year 2020. The policy that makes solid fuel like RDF from flammable wastes and uses them as combustion fuel of electricity generations has been found to be the most efficient and effective one among five policies. The cumulative abatement amount when five policies not mutually exclusive are applied sequentially has been reckoned.
잡음음성 음향모델 적응에 기반한 잡음에 강인한 음성인식
정용주(Chung, Yongjoo) 한국음성학회 2014 말소리와 음성과학 Vol.6 No.2
In the Vector Taylor Series (VTS)-based noisy speech recognition methods, Hidden Markov Models (HMM) are usually trained with clean speech. However, better performance is expected by training the HMM with noisy speech. In a previous study, we could find that Minimum Mean Square Error (MMSE) estimation of the training noisy speech in the log-spectrum domain produce improved recognition results, but since the proposed algorithm was done in the log-spectrum domain, it could not be used for the HMM adaptation. In this paper, we modify the previous algorithm to derive a novel mathematical relation between test and training noisy speech in the cepstrum domain and the mean and covariance of the Multi-condition Training (MTR) trained noisy speech HMM are adapted. In the noisy speech recognition experiments on the Aurora 2 database, the proposed method produced 10.6% of relative improvement in Word Error Rates (WERs) over the MTR method while the previous MMSE estimation of the training noisy speech produced 4.3% of relative improvement, which shows the superiority of the proposed method.