• 한국음향학회지
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• 제19권4호
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• pp.58-68
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• 2000

본 논문에서는 폴리포닉 오디오 신호에 대한 정현파 모델링 방법을 제안한다. 정현화 모델링을 폴리포닉 오디오 신호에 적용하는데 있어서 가장 큰 문제점은 스펙트럼 분석을 위한 분석 윈도우의 크기를 결정할 수 없다는 것이다. 또한 고음질의 합성음을 위해서는 악기음의 특성을 결정짓는 어택이 잘 보존되어야 한다. 본 논문에서는 입력 신호를 6개의 옥타브 벤드 구조의 다중 해상도 필터 뱅크를 통과시키고, 각 서브벤드 신호에 대해 서로 다른 크기의 분석 윈도우를 적용시킴으로써 폴리포닉 오디오 신호에 대한 분석 윈도우 크기 결정 문제를 해결한다. 정현파 모델링에서 발생하는 어택과 같은 천이 구간에서의 퍼짐 현상을 개선하기 위해 각 서브밴드 신호에 동적 세그맨테이션 방법을 적용하여 천이 구간 근처에서는 분석과 합성 프레임 크기를 작게 하는 방법을 사용한다. 이 방법을 통해 서브밴드 신호의 구간별 시간-주파수 특성에 따라 적절한 크기의 윈도우를 선택할 수 있다. 동적 세그멘테이션 방법으로는 기존의 방법보다 계산량과 성능 면에서 더 나은 특성을 보이는 방법을 제안한다. 여러가지 폴리포닉 오디오 신호에 대한 시뮬레이션 결과 제안한 정현파 모델링 방법이 음질의 손상 없이 원래 신호를 잘 복원할 수 있음을 확인하였다.

• 가정과삶의질연구
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• 제19권4호
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• pp.211-223
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• 2001

This study analyzed the financial ratio change of self-employed households between 1997 and 1998. The data were drawn from Korean Households Panel Study and utilitze7 descriptive statistics such as frequency, percentile to investigate the differences between two period of time, 1997 and 1998. The sampe size in 1997 was 692 householdsand and 600 households in 1998. The mean of financial asset showed that in 1997, self-employed households had much less in liquidity assets, especially in bank-related income, stock, but had more in real-estate, Gye, and private loan than those in 1998. In cases of debt-owned, the self-employed tended to have more debt in non-bank related and it illustrates that the self-employed may experience the difficulties to access the financial assistance in economic depression. Using guideline of each ratios, for six financial ratios, self-employed could meet less proper level$ in 1998 compared to those in 1997. It proves that the economic crisis affect the stability of income and financial assets of self-employed households and types of financial assets changes because of the stability.

• 농촌계획
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• 제20권3호
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• pp.55-66
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• 2014

Under high agricultural automation in rice farming, cultivation acreage expansion can be considered for the economies of scale. Also, considering the circumstances of higher ratio in leased farms than independent farms, Long-term Leasing Business of Farmland can be the most public and transparent method to expand cultivation acreage for lease farming. Therefore, this research observes the various factors such as application motives, satisfaction, and demands of Long-term Leasing Business of Farmland, which the importance is on the rise and serves as a means to increase agricultural expansion, as well as its operational performance analysis. The research results and implications are as follows. Long-term Leasing Business of Farmland have positive effects such as ensuring stable farming through documental contract, providing convenience because the lease contractor requires no meetings during the contract period, providing opportunities to expand the farm size, and acquiring economical gain which is linked to satisfaction aspects of the businesses. On the other hand, demands such as strengthened business advertisement, writing business documents by correlating with related organizations, and clear lease price configuration were made by the businesses. To bring improvements, this research proposes; 1) expanding support to related businesses, 2) providing convenience through related organization correlations, and 3) configuring clear lease prices considering the regional conditions.

• The Journal of Asian Finance, Economics and Business
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• 제7권11호
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• pp.1-11
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• 2020

This study aims to investigate whether Corporate Social Responsibility (CSR) performance can help companies gain more bank unsecured loans. Additionally, this study analyzes the moderating effect of firm size and industry characteristics. Data was collected through the case of companies listed on the Shanghai Stock Exchange or the Shenzhen Stock Exchange in China between 2009 and 2018 with 5373 firm-year observations. The results of multivariable regression analysis show that good CSR performance exhibits a strong positive impact on unsecured debt, including short-term, long-term, and total unsecured debt, which indicates that corporate with good CSR performance can borrow more unsecured debt. further research shows that this effect is more pronounced for small enterprises and firms operating in heavy-polluting industries. Additionally, research on the impact mechanism finds that good CSR performance can help mitigate information asymmetry between borrower and lender, reduce moral hazard of borrower, and obtain support from key stakeholders, and therefore reduces the risk of default. The findings of this study suggest that firms with good CSR performance exhibit a preference for unsecured debt, but decline to provide collateral for debt. Overall, we emphasize and illustrate the important role of corporate CSR in bank credit financing.

• Journal of Power Electronics
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• 제5권4호
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• pp.289-304
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• 2005

This paper describes a simple control structure and power conditioning system for an indirect vector controlled stand-alone induction generator (IG) used to operate under variable speed. The required reactive power for the IG system is supplied by means of a capacitor bank and a voltage-source PWM converter. Using a capacitor bank to transfer the reactive power to the IG under the rated speed and no-load conditions starts the IG operation and reduces the PWM converter size. The vector control structure for the variable speed IG power conditioning system compensates for changes in the electrical three-phase and DC loads while considering the magnetizing curve of the IG. The vector control structure is developed to regulate the DC link voltage of the PWM converter and the IG output voltage. The experimental and simulated performance results of the IG power conditioning system at various speeds and loads are given and show that this proposed scheme can be used efficiently for a variable speed, wind energy conversion system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1339-1342
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• 2005

This paper presents a simple AC-DC power conditioner for a squirell-cage induction generator(IG) operating under variable shaft speeds. The necessary reactive power for the IG system is supplied by means of a capacitor bank and a voltage-source PWM converter. Using a capacitor bank to transfer the reactive power to the IG under the rated speed and no-load conditions starts the IG operation and reduces the PWM power converter size. A simple control compensating for changes in the electrical loads as well as the variation in speed was developed to regulate the voltages of the IG system by controlling the rotor flux through its reactive and active currents control implementation. This proposed power conditioning scheme can be used efficiently as a wind power generation system where the output voltage of the IG is maintained constant voltage despite the variable frequency and the DC bus voltage of the PWM converter can be used for either DC applications such as battery charging or AC power applications with 60/50 Hz by connecting a stand alone inverter. The experimental and simulated operating performance results of a 5 kW IG scheme at various speeds and leads are presented.

• Asia pacific journal of information systems
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• 제9권1호
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• pp.39-58
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• 1999

This study examines whether expenditures in information technology (IT) are associated with increases in Tobin's q ratios, a measure of management performance, in the banking industry. The association between IT expenditures and Tobin's q ratios is different, depending upon the banks' size (national vs regional) and strategic orientation (wholesale vs retail), in the Korean commercial banks for the period studied 1990-1996, For national commercial banks which have more clients and electronic banking systems than regional banks, IT expenditures appear to increase Tobin's q ratios. This may indicate that IT is linked to the ability to achieve economies of scale or network effects when large banks use IT as a strategic tool. The association between IT expenditures and management performance measures is also positive and statistically significant for retail-oriented banks. This research makes two important practical contributions with respect to financial reform. First, the evidence suggested that Korean commercial banks need to apply IT strategy in conjunction with restructuring strategy to be a super-bank and, hence, reap substantial competitive advantage from IT applications. Second, since the government recently encouraged commercial banks to increase credit loans as a means of financial reform, most banks tend to focus on retail banking. IT used in the retail banking sector contributes to improve management performance as the evidence suggested.

• 신재생에너지
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• 제8권4호
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• pp.13-20
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• 2012

This paper describes a transformerless static synchronous campensator (STATCOM) system based on cascade H-bridge multilevel inverter with star configuration. It is designed not only for the dynamic and continuous compensation of the reactive power but also for the improvement of power quality of existing wind power plant. Especially, when the induction generator of wind turbine is directly connected to the grid, reactive power are occurred by exiting current. so a reactive power compensation system based on the cascade H-bridge multilevel STATCOM is proposed because the output power quality and controllability of reactive power are required by grid code in many different countries. Using various The proposed reactive power control strategy using a STATCOM is compared with the conventional scheme using fixed-size of capacitor bank through various simulation results.

• The Journal of Asian Finance, Economics and Business
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• 제8권11호
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• pp.41-46
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• 2021

The purpose of this study is to investigate the relationship between unemployment and shadow economy for 7 selected ASEAN countries using panel data from 2000-2017. This study uses a sample of 7 ASEAN countries including Cambodia, Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam covering the 2000-2017 period. The stationarity of the variables is determined by Pesaran panel unit-root tests. The Westerlund panel co-integration technique is used to examine the long-run relationship among the variables. In addition, dynamic ordinary least squares (DOLS) and fully modified ordinary least squares (FMOLS) methods are also employed. The DOLS and FMOLS results indicate that unemployment acts as an important driver for the increase in the shadow economy. In addition, the study results also reveal that GDP per capita has a negative impact on the shadow economy. Moreover, government expenditure, bank credit, and inflation are positively related to the shadow economy. The empirical results indicate that the size of the shadow economy is boosted by unemployment in the selected ASEAN economies. In addition, it is also evident that an increase of GDP per capita in the sample countries results in a lower shadow economy. Besides, government expenditure, bank credit, and inflation play a crucial role in the shadow economy.

• 한국환경과학회지
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• 제28권8호
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.