• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.815-818
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• 2000

본 논문에서는 감정 표현 음성 합성 시스템을 구현하기 위해서, 감정 음성 데이터베이스의 음향학적 특징인 피치, 에너지, 지속시간, 스펙트럼 포락에 대해 분석한 결과와 문법적 요소인 품사에 따른 감정 음성 데이터의 피치 변화를 분석하였다. 분석 결과, 기본 주파수, 에너지, 지속시간, 스펙트럼 포락은 감정 표현에 중요한 영향을 미치는 것으로 나타났으며, 전반적으로 화남과 기쁨의 감정이 평상과 슬픔의 감정 보다 피치 및 에너지의 변화가 크게 나타났으며, 특히 기쁜 감정의 경우 부사, 관형사, 연결어미, 조사, 접미사에서 피치 변화가 많았으며, 화난 감정의 경우, 관형사, 명사, 용언, 접미사에서 피치 변화가 높게 나타났다. 이러한 분석 결과를 적용해 감정 음성을 합성하기 위하여, 평상 음성에 각 감정 음성의 운율 요소를 적용하여 감정 음성을 합성하여 평가한 결과, 기쁜 감정은 기본 주파수의 변화에 의해 86.7%, 화난 감정은 에너지의 변화에 의해 91%, 슬픈 감정은 음절지속시간의 변화에 의해 76.7%가 각각 올바른 감정으로 인지되었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.33-36
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• 2007

Acoustic holography exhibits the spatial distribution of sound pressure in time or frequency domain. The obtained picture often contains far more than what we need in practice. For example, when we need to know only the locations and overall propagation pattern of sound sources, a method to show only what we need has to be introduced. One way of obtaining the necessary information is to use envelope in space. The spatial envelope is a spatially slowly-varying amplitude of acoustic waves which contains the information of sources' location. A spatial modulation method has been theoretically developed to get a spatial envelope. By applying the spatial envelope, not only the necessary information is obtained but also computation time is reduced during the process of holography. The spatial envelope is verified as an effective visualization scheme in time domain by being applied to complicated sound fields.

• Journal of the military operations research society of Korea
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• v.36 no.3
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• pp.1-13
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• 2010

DEA method has been widely applied on civilian and defense side for efficiency analysis of organizations and programs(project). For many years Defense Industry, military hospital and military construction parts have been analyzed by using DEA method. In this paper we review and propose a method of warship evaluation through DEA method. The evaluation method proposed above can provide plenty of proper information for ROC decision, AOA and source selection on weapon acquisition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.905-910
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• 2008

Vibration analysis is widely used in machinery diagnosis and the wavelet transform has also been implemented in many applications in the condition monitoring of machinery. In contrast to previous applications, this paper examines whether acoustic signal can be used effectively along vibration signal to detect the various local fault, in local fault of gearboxes using the wavelet transform. Moreover, envelop analysis is well known as useful tool for the detection of rolling element bearing fault. In this paper, a acoustic emission (AE) sensor is employed to detect gearbox damage by installing them around bearing housing at driven-end side. Signal processing is conducted by wavelet transform and enveloping to detect her fault all at once gearbox using AE signal.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.137-140
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• 2006

본 논문에서는 일반적인 MP3 오디오에서 손실된 고주파 성분을 복원하여 향상된 품질의 오디오를 제공하는 방법을 고찰한다. 고주파 복원을 위해 먼저 MP3 오디오에 따라 손실된 고주파 영역이 차이남을 참조하여 고주파 복원 시작 대역을 결정한다. 그런 다음, IMDCT 이후 32개 대역으로 분할된 대역 신호의 에너지를 이용하여 고주파 대역의 에너지 포락선을 추정한다. 추정된 에너지 포락선을 참조하여 저주파 대역 신호를 복사하거나 AWGN 신호를 삽입함으로써 손실된 고주파 신호를 복원하다. 본 논문에서는 주관적 음질 평가 및 스펙트럼 분석을 통해 제안한 방법의 성능을 평가한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.133-134
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• 2018

본 연구는 우리나라 물류기업의 경영 효율성 비교 분석을 통해 물류기업의 특성별 차이가 있는지 파악하였다. 분석방법은 효율성을 측정하는데 유용한 자료포락분석(DEA)의 CCR 및 BCC 모형을 이용했다. 투입변수는 종업원 수와 매출원가를 사용하였고, 산출변수는 매출, 영업이익과 당기순이익을 사용하였다. 분석자료는 2016년도 공시된 금융감독원 전자공시시스템의 자료를 활용했다. 분석결과 고효율성으로 나타난 물류기업의 수는 3자 물류기업이 많았으며, 효율성이 높은 2자 물류기업들은 우리나라 대기업의 물류 자회사로서 모기업 및 계열사들의 물량을 바탕으로 내부거래 비율이 높은 것으로 나타났다.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2006.11b
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• pp.455-469
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• 2006

• Proceedings of the KOR-KST Conference
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• 2007.11a
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• pp.191-200
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• 2007

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.605-616
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• 2014

The purpose of this study is to analyze transport efficiency of each of the 17 urban railway lines being operated by national public agencies using Data Envelopment Analysis (DEA) and to seek strategies for improving efficiency of the urban railway system. The study identified the economies of scale derived from these values of efficiency and examined the effects on cost for free ride loss and profit of transport by the fare system as the external factor. At the time, Transport profits are estimated by two production factors such as the number of vehicles and service frequency derived from multiple regression. Finally, the measures to improve the efficiency were presented in terms of profitability in the national urban railway line by applying the values of efficiency derived from DEA to multidimensional scaling (MDS).

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.59-68
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• 2002

Using 1996 annual observations for 69 bus firms in Seoul, this paper measures firm-level efficiency with data envelopment analysis(DEA) and identifies firm characteristics indicative of differential efficiency in these firms with Tobit regression analysis. The paper then conceptualizes that these firms produce two kinds of output(city/seat bus kilometers or city/seat bus Passengers) using four inputs (labor vehicle, fuel and maintenance). The findings show that, on an average, these firms have only a little input saving potential of 0.9 percent, while not a little output increasing potential of 12.9 percent. On the other hand, it is discovered that these firms operate more efficiently with a lower ratio of maintenance employees to total employees. Furthermore, it appears that both the ratio of seat buses to total buses and average speeds positively affect efficiency in this industry.