• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.48-55
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• 2010

It has a falling off in speech quality, especially when consecutive packet loss occurs, even if a vocoder implemented in the packet network has its own packet loss concealment (PLC) algorithm. PLC algorithm is divided into transmitter and receiver algorithm. Algorithm in the transmitter gives superior quality by additional information. however it is impossible to provide mutual compatibility and it occurs extra delay and transmission rate. The method applied in the receiver does not require additional delay. However, it sets limits to improve the speech quality. In this paper, we propose a new method that puts extra information for PLC in a part of Extension Header Data which is not used in RTP Header. It can solve the problem and obtain enhanced speech quality. There is no extra delay occurred by the proposed algorithm because there is a jitter buffer to adjust network delay in a receiver. Extra information, 16 bits each frame for G.729 PLC, is allocated for MA filter index in LP synthesis, excitation signal, excitation signal gain and residual gain reconstruction. It is because a transmitter sends speech data each 20 ms when it transfers RTP payload. As a result, the proposed method shows superior performance about 13.5%.

• Studies on Korean Youth
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• v.30 no.3
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• pp.5-32
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• 2019

The purpose of this study was to compare methods of model specification to control covariates in mediation analysis with structural equation modeling. In order to do this, monte carlo simulation was conducted. In this study, five models were compared, and each model was evaluated based on both the accuracy of estimates and model fit. The results showed that when the NC(Non Control) model was applied, model fit was good, however, estimates of mediation effect, direct effect, and total effect were all found to be biased. In terms of both the OC(Outcome Control) model and the COC(Correlated Outcome Control) model, estimates of mediation effect and total effect were biased. Additionally, model fit was found to be unacceptable in both the OC model and the COC model. When the MOC(Mediator-Outcome Control) model was applied, the estimates were unbiased, but under certain conditions, model fit was unacceptable. In the CMOC model, estimates of mediation effect, direct effect, and total effect were all unbiased, and model fit was good. Based on these results, for the purposes of controlling covariates in mediation analysis, the CMOC model was suggested as being the most appropriate.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.3
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• pp.64-71
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• 2024

This study investigated the electrical conductivity, pH, and diastase activity characteristics of 31 types of domestic and imported honey, which are not currently used in the Korean honey grading system, to determine the feasibility of introducing these indicators into the honey grading system. The results showed that the moisture content of domestic and imported honey is around 20%, indicating that domestic quality standards are relatively well controlled, and the pH values are distributed in the range of pH 3.91 to 6.31. The electrical conductivity of domestic and imported honey ranged from 0.09-1.51mS/cm, which showed a large difference between the samples. Although there was a large difference of electrical conductivity from the honey types, further research is needed to determine whether it is applicable to Korean honey. Finally, in the case of diastase activity, Korean honey showed relatively high DN values compared to imported honey from Vietnam, New Zealand, the United States, and China. Therefore, diastase activity is an important indicator for evaluating the quality of honey, and further research is needed to confirm its feasibility as an additional indicator for the domestic honey grading system in Korea. This study evaluated the physical properties and enzyme activity characteristics of domestic and imported honey, and is expected to provide basic information for the establishment of a honey grading system, thereby improving consumer trust in the honey grading system and enhancing the development of honey distribution in Korea.

• Journal of the Korean Regional Science Association
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• v.33 no.2
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• pp.39-46
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• 2017

This study estimated indirect economic benefits of the introduction of Korean Spatial Information System. Korean academic society has been reluctant to consider indirect benefits as an item of benefits in cost-benefit analysis. Nevertheless, other countries including England recommend to consider some indirect benefits like option value as an important item of cost-benefit analysis, especially in the case of transportation projects. This study estimated indirect benefits of the introduction of Korean Spatial Information System using Contingent Valuation Methods: Indirect benefits of the project are so significant in terms of statistics and substantial in terms of magnitude that decision making can differ from the case without consideration of such indirect benefits.

• Nuclear industry
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• v.19 no.7 s.197
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• pp.60-73
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• 1999

미국과 옛 소련의 냉전 체제가 붕괴된 후 세계의 핵관리 체제는 NPT$\cdot$CTBT등을 통해 핵확산 방지를 위해 노력을 기울이고 있다. 이러한 시점에서 인도의 98년 5월 11일, 13일의 핵실험과 파키스탄의 5월 29일, 6월1일의 핵실험은 국제 사회의 핵확산 방지에 큰 파문을 일으킨 바 있다. 이러한 점에서 <원자력산업> 4$\cdot$5월호에서 2회에 걸쳐 연재되었던 아시아 주요국의 원자력 개발 동향 조사가 평화적 목적의 원자력 이용 중심이었던 데 비해 이번 호에서는 양국의 핵실험 관련 자료를 추가 기술하고자 한다.

• ETRI Journal
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• v.9 no.4
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• pp.85-96
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• 1987

본고에서는 CCITT 권고안(TMN)의 개념에 의거하여 국내 ISDN을 효율적으로 지원하고, 기능의 추가 및 확장이 가능한 형태의 ISDN O&M의 구조를 제안하여 ISDN O&M를 기능적으로 감시제어부, 유지보수 및 망 관리부로 구분하고 이러한 O&M 구조하에서 기존 O&M 기능과의 정합을 위하여는 운용망 인터페이스를 통하여 기능적으로 접속되어야 하고 새로운 NE와 OS간의 기능 분담에 관하여 언급하고 있다.

• Korean Journal of Child Studies
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• v.5
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• pp.47-52
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• 1984

인지 어휘 유형(cognitive dictionary)이란 단어 연상의 반응 어휘를 인지 유형에 따라 분류, 분석하는 것을 가리킨다. 인지 어휘 유형 개념을 McNeill의 언어 발달 연구에 준하여 논의하였다. 즉 아동의 어의(語義) 발달은 자작문(自作文) 형식(形式) 표현에서 시작되어 어휘 사용에 이른다는 것이다. 한편 Moran은 범세계적으로 유아들의 인지 어휘 유형은 단어의 동작적(動作的) 특성에 주로 의거한다는 것을 발견했는데 이는 언어의 효시에 관한 Piaget 나 Bruner의 이론과 일치하는 것이다. Moran의 인지 어휘 유형의 추가 개념은 Bruner의 심상(心象)(ikonic representation)에 의한 관계, 기능적 관계 (functional representation), 논리적(logical)관계를 포함한 단어의 연합 관계에 반영시켰다.

• The Bulletin of The Korean Astronomical Society
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• v.32 no.2
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• pp.26.1-26.1
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• 2007

• The Korean Journal of Applied Statistics
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• v.12 no.2
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• pp.479-490
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• 1999

선형시계열모형인 AR(1)모형과 비선형시계열모형인 RCA(1), ARCH(1)모형에서 이상치(Outlier)가 존재할 경우 최소제곱추정량과 M추정량간의 점근상대효율(Asymptotic Relative Efficiency: ARE)을 구하여 두 추정량의 로버스트 성질을 비교·분석하였다. 또한 여러 유계함수(Huber, Tukey, Andrews, Hampel)들을 M추정함수에 적용하여 각각의 유계함수들을 비교·분석하였다.

• The Korean Journal of Applied Statistics
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• v.12 no.2
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• pp.449-461
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• 1999

본 논문에서는 패널회귀모형에서 내부변환(within transformation) 추정량을 이용하여 회귀계수에 대한 정확한 신뢰구간을 제시하였다. 아울러 이러한 신뢰구간의 효율성을 신뢰계수(confidence coefficient)와 신뢰구간의 평균길이(average length of confidence interval)을 사용하여 모의실험을 통하여 다른 근사적 신뢰구간들과 비교하였다. 실험결과, 내부변환추정량을 이용한 신뢰구간은 다른 근사적 신뢰구간들에 비해 명목신뢰계수를 정확히 유지하였고, 신뢰구간의 평균길이도 다른 방법들에 비해 짧은 결과를 보았다.