• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.1-5
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• 2004

A new method for the estimation of pitch-frequency contour of voiced speech is presented. The method is based on the double application of Kaiser's energy operator［1］, which has the capabilities of extracting amplitude and frequency of a sinusoidal waveform. According to the modulation model, a vowel can be represented by a combination of damped sinusoids representing formants, modulated by pitch pulses. Therefore, the amplitude envelope of each of the components will give a pitch-like waveform and the pitch can be obtained by averaging the frequencies of this waveform. The first part is the same as Gopalan's approach［9］, but by substituting the LPC based spectral analysis with the second application of energy operator, the algorithm becomes very simple and can be processed on-line. Although the estimation is rather coarse, the suggested algorithm can be useful for getting a general sketch of pitch contour on-line.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.8
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• pp.67-75
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• 2000

In this paper, we proposed a new method to find dive parameters of an ellipse from the optical Hough transform (HT) results. The method employs the HT for detection of a straight line and the one-dimensional analysis of the resultant parameter domain. Using this algorithm, we simulated about the ellipses with different positions, and obtained the information of the ellipse with 94% accuracy in the worst case. To compare the simulation results with the experimental ones, we performed optical experiments using a HT Computer Generated Hologram (CGH) filter. Through the experiments, we showed that our results were very similar to the simulation results.

• Journal of Environmental Policy
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• v.8 no.4
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• pp.37-49
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• 2009

While water management policies in Korea have focused on industrial water demand during the last decade, the amount of industrial water usage has decreased significantly. This paper estimates the technical efficiency of industrial water in order to test whether the reduction of industrial water usage is a result of improving the level of technical efficiency of industrial water. This paper shows that the technical efficiency of industrial water use slightly decreased from 0.5183 in 1998 to 0.4853 in 2003. In addition, these estimates are much less than those of other inputs and so, there is still much room for reducing the amount of industrial water use through improving technical efficiency even though the average productivity of industrial water has improved during this period.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.501-507
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• 1999

At the mobile unit for adaptation the propagation environment, it is necessity to adapt very fast the weight coefficient vector of adaptive array antenna In this paper, for the BPSK and BFSK signals with S/I=2, S/N=10 subband adaptive array signal processing method to the linear array antenna using the LMS & the Kalman filter algorithm is proposed. For the 4 elements equidistance linear array antenna systems LMS and Kalman algorithms with subband adaptive instruction principles using the subband signal processing method are adopted and the computer simulation results to the constant amplitude envelope signals such as BPSK or BFSK can be seen that the convergence characteristics of directional patterns and the signal following characteristics are more fast and stable.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.422-424
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• 2011

오늘날과 같이 급속히 변화하는 기업경영 환경에서 조직이 생존하고 번영하기 위해 기업의 경영 성과를 향상시켜야 하고 이를 위해서는 생산성 또는 효율성을 꾸준히 평가할 필요가 있다. 본 연구는 평가대상의 상대적 효율성을 측정하기 위해 개발된 DEA(Data Envelopment Analysis) 방법론을 이용하여 국내 컨테이너터미널 운영사의 경영 효율성을 비교 분석함으로써 2007년부터 2009년까지의 터미널 운영사의 효율성 수준을 파악해 보았다. 연구결과 2007년부터 2009년까지 점차적으로 영업이익률이 줄어드는 현상이 나타나는데, 이것은 산출변수에는 큰 변화가 없는 반면 투입변수는 지속적으로 증가하고 있다는 것을 알 수 있다. 이것은 동 기간 사이에 컨테이너터미널 업체수는 증가하였음에도 불구하고 물동량의 증가가 미미하여, 물동량 확보를 위한 터미널 업체들간의 경쟁이 치열해졌다는 것을 알 수 있다. 이러한 경쟁은 하역요율의 단가하락 문제를 발생시켰으며, 이로 인해 업체들의 경영악화가 가속되었다는 것을 의미한다. 본 연구 결과는 물동량 변화에 따른 투입변수의 최적화를 통해 컨테이너터미널 운영사의 경영효율성을 제고하는데 기여 할 것으로 판단된다.

• The Journal of Fisheries Business Administration
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• v.34 no.2
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• pp.109-129
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• 2003

The purpose of this study is to evaluate the managerial efficiency of fisheries cooperatives in Korea by using data envelopment Analysis(DEA). The DEA method is a relative evaluation method on the basis of linear programming. Also, it is known as a useful method for the evaluation of not-for-profit organizations which cannnot be measured by mere monetray units for their performances. The 50 units have been taken for the purpose of analysis. All of the units are homogeneous groups, and the produce multiple services with multiple inputs. Input variables are a number of employee, fixed assets, and business managerial costs. Output variables include a number of deposits, a number of loans, a total deposits, a total loans, and operational income for one year. The empirical results of this study are as follows. First, the average technical efficiency showed 82.35% which revealed about 17.65% of non-efficiency in 2001. Second, in 15 DMUs, the overall inefficiency is mainly attributed to their efficient operations or management. To be opposed, in 18 DMUs, the overall inefficiency is mainly attributed to their scale efficiency. Third, efficiency ranking results by DEA do not agree with the ratio analysis by fisheries cooperatives. Fourth, average efficiency level by year was improving gradually by 0.7408 in 1999, 0.8023 in 2000, and 0.8235 in 2001 at significant 10% level.

• The Journal of Fisheries Business Administration
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• v.39 no.3
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• pp.49-65
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• 2008

In Korea, deep-sea fishing industry is faced with pressure of being thrown out of business, because of the upcoming unfavorable business conditions such as the fishing regulation of coastal countries, Korea-US Free Trade Agreement(KORUS FTA), and the other socio-economic changes. Hence, we present an evaluation of future business competitive for the deep-sea fishing industry so that the government can develop a concession plan for the deep-sea fishing industry by utilizing the results of this study. In efficiency analysis of deep-sea fishing industry, the decision maker may have two problems: (1) how to deal with multiple inputs and outputs of deep-sea fishing industry and (2) how to assign the weights on different inputs and outputs, In this paper, we proposed to use Data Envelopment Analysis (DEA) to estimate efficiency of deep-sea fishing industry with multiple inputs and outputs. In the DEA, The direct impact of KORUS FTA, fishing regulation of coastal countries, fishing charges, and competitive fishing conditions were used as input parameters while the profitability and secured fishing quarters, as outputs. The results of DEA-BCC model indicate that 6 out of 12 DUMs have better efficiency under variable return to scale assumption.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.1-6
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• 2008

In this paper, bias control circuit structure have been employed to improve the power added efficiency of the CMOS class-E power amplifier on low input power level. The gate and drain bias voltage has been controlled with the envelope of the input RF signal. The proposed CMOS class-E power amplifier using bias controlled circuit has been improved the PAE on low output power level. The operating frequency is 2.14GHz and the output power is 22dBm to 25dBm. In addition to, it has been evident that the designed the structure has showed more than a 80% increase in PAE for flatness over all input power level, respectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.3
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• pp.317-327
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• 2001

In this paper, a relation to calculate design moments for reinforced concrete(RC) bridges constructed by movable scaffolding system(MSS) is introduced. Through the time-dependent analysis of RC bridges considering the construction sequence, the structural responses related to the member forces and deflections are reviewed, and a governing equation for determination of the design moment, which includes the creep deformation, is derived on the basis of the displacement-force condition at every constructuion stage. By using the relation, the design moment and its variation over time can easily be obtained only with the elastic analysis results without additional time-dependent analysis. In addition, correlation studies with the results by rigorous numerical analyses are conducts to verify the applicability of the introduced relation, and a more reasonable guideline for the determination of design moments is proposed on the basis of the obtained moment envelop.

• The Journal of the Acoustical Society of Korea
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• v.15 no.4
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• pp.18-23
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• 1996

Fluctuation statistics of scattering strength are not only important because they impact the performance of active sonar systems, but also because they may provide insight into the major scattering process. In this article, analysis of the statistical characteristics of bottom backscattering, measured in shallow water, are presented. The slowly moving experimental sonar was operated at 30kHz to gather data over the bottom. Spatial and temporal correlation functions of the signal amplitudes were measured. The distribution function and probability of false alarm function of the detected envelope of widebeam and narrowbeam signals were measured. An attempt was made to compare the results with existing theoretical models. The result suggests that the statistical characteristics of bottom backscattering fluctuation of moving source is differ from that of fixed source.