• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.276-280
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• 2016

A fixed rate speech coder based on the filter bank and the non-uniform sampling technique is proposed. The non-uniform sampling is achieved by the detection of inflection points (IPs). A speech block is band passed by the filter bank, and the subband signals are processed by the IP detector, and the detected IP patterns are compared with entries of the IP database. For each subband signal, the address of the closest member of the database and the energy of the IP pattern are transmitted through channel. In the receiver, the decoder recovers the subband signals using the received addresses and the energy information, and reconstructs the speech via the filter bank summation. As results, the coder shows fixed data rate contrary to the existing speech coders based on the non-uniform sampling. Through computer simulation, the usefulness of the proposed technique is confirmed. The signal-to-noise ratio (SNR) performance of the proposed method is comparable to that of the uniform sampled pulse code modulation (PCM) below 20 kbps data rate.

• 대한전자공학회논문지SD
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• 제44권4호
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• pp.10-17
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• 2007

FTIR 분광계는 간섭계를 사용하여 표적 물질에 대한 간섭무늬를 획득하고, 이를 푸리에 변환함으로써 기체상태 물질의 적외선 영역 스펙트럼을 획득하기 위한 유용한 기법이다. 본 논문에서는 불규칙적 위치에서 간섭무늬 샘플링에 관하여 고속 스캔 간섭계의 신호처리에서의 샘플링 노이즈 영향에 대한 연구와 이에 대하여 실험적으로 검증 하였다.

• 대한토목학회논문집
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• 제2권3호
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• pp.101-107
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• 1982

밀도증가식(密度增加式) 표본추출법(標本抽出法)은 입력지형(入力地形)의 변이성(變異性)에 잘 부합되고 가장 효율적(効率的)인 표본추출법중(標本抽出法中)의 하나이다. 이들 효율성(効率性)들은 몇 가지의 추출조건(抽出條件)을 부과하여 잉여점(剩餘點)들을 제외(除外)시킴으로서 그 효율성(効率性)을 크게 향상(向上)시킬 수 있다. 연구(硏究)에서는 추출조건(抽出條件)으로서 4가지 즉(即), 표준형(標準形), 도약형(跳躍形), 유보형(留保形), 혼합형(混合形)을 적용하여 수치시험을 실시(實施)하였으며 그 결과 그 중에서 유보형조건(留保形條件)이 가장 주목할 만한 추출조건(抽出條件)임을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.209-212
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• 1988

This paper presents a new uniform sampling method for two-dimensional contour. The proposed method improves the uniformity of contour sampling in terms of the interpolation of the corner points extracted from chain codes. The performance of the proposed method is analyzed through the length estimation and shape recognition of two-dimensional contour. The experimental results show the significant improvement over the conventional method.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.767-771
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• 2002

This paper proposes a multivariate $T^2$ variable interval control chart with sampling at fixed times, where samples are taken at specified equally spared fixed time points, and additional samples are allowed between these fixed times when indicated by the preceding $T^2$ statistics. At fixed sampling tunes, the $T^2$ statistics are composed of all quality characteristics, and a part of qualify characteristics are selected to obtain $T^2$ statistics at additional sampling times. A Markov chain approach is used to evaluate the performance of the proposed chart.

• Journal of Biosystems Engineering
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• 제33권4호
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• pp.260-268
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• 2008

Optical diffuse reflectance sensing has potential for rapid and reliable on-site estimation of soil properties. For good results, proper calibration to measured soil properties is required. One issue is whether it is necessary to develop calibrations using samples from the specific area or areas (e.g., field, soil series) in which the sensor will be applied, or whether a general "factory" calibration is sufficient. A further question is if specific calibration is required, how many sample points are needed. In this study, these issues were addressed using data from 42 paddy fields representing 14 distinct soil series accounting for 74% of the total Korean paddy field area. Partial least squares (PLS) regression was used to develop calibrations between soil properties and reflectance spectra. Model evaluation was based on coefficient of determination ($R^2$) root mean square error of prediction (RMSEP), and RPD, the ratio of standard deviation to RMSEP. When sample data from a soil series were included in the calibration stage (full information calibration), RPD values of prediction models were increased by 0.03 to 3.32, compared with results from calibration models not including data from the test soil series (calibration without site-specific information). Higher $R^2$ values were also obtained in most cases. Including some samples from the test soil series (hybrid calibration) generally increased RPD rapidly up to a certain number of sample points. A large portion of the potential improvement could be obtained by adding about 8 to 22 points, depending on the soil properties to be estimated, where the numbers were 10 to 18 for pH, 18-22 for EC, and 8 to 22 for total C. These results provide guidance on sampling and calibration requirements for NIR soil property estimation.

• International Journal of Contents
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• 제2권2호
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• pp.17-24
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• 2006

The work presented in this paper is divided into two parts. The first part presents finite urn problems which generate truncated negative binomial random variables. Some combinatorial identities that arose from the negative binomial sampling and truncated negative binomial sampling are established. These identities are constructed and serve important roles when we deal with these distributions and their characteristics. Other important results including cumulants and moments of the distributions are given in somewhat simple forms. Second, the distributions of the maximum of two chi-square variables and the distributions of the maximum correlated F-variables are then derived within the negative binomial sampling scheme. Although multinomial theory applied to order statistics and standard transformation techniques can be used to derive these distributions, the negative binomial sampling approach provides more information and deeper insight regarding the nature of the relationship between the sampling vehicle and the probability distributions of these functions of chi-square variables. We also provide an algorithm to compute the percentage points of these distributions. We supplement our findings with exact simple computational methods where no interpolations are involved.

• International Journal of Contents
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• 제3권1호
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• pp.1-8
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• 2007

The distributions of the minimum correlated F-variable arises in many applied statistical problems including simultaneous analysis of variance (SANOVA), equality of variance, selection and ranking populations, and reliability analysis. In this paper, negative binomial sampling technique is employed to derive the distributions of the minimum of chi-square variables and hence the distributions of the minimum correlated F-variables. The work presented in this paper is divided in two parts. The first part is devoted to develop some combinatorial identities arised from the negative binomial sampling. These identities are constructed and justified to serve important purpose, when we deal with these distributions or their characteristics. Other important results including cumulants and moments of these distributions are also given in somewhat simple forms. Second, the distributions of minimum, chisquare variable and hence the distribution of the minimum correlated F-variables are then derived within the negative binomial sampling framework. Although, multinomial theory applied to order statistics and standard transformation techniques can be used to derive these distributions, the negative binomial sampling approach provides more information regarding the nature of the relationship between the sampling vehicle and the probability distributions of these functions of chi-square variables. We also provide an algorithm to compute the percentage points of the distributions. The computation methods we adopted are exact and no interpolations are involved.

• 한국치위생학회지
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• 제20권6호
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• pp.875-888
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• 2020

Objectives: The purpose of this study was to investigate the infection control system and actual conditions according to the type of dental medical institution. Methods: From April 1st to May 10th, 2020, dental institutions were recruited through stratified random sampling. Each item constituting the infection control system by dental institution type was analyzed using the chi-square test and fisher's exact test. Results: The infection control system and operation level of each dental institution type was 89.0 points for university-general hospitals, 75.6 points for dental hospitals, and 34.4 points for dental clinics. The environment management levels were 76.1, 72.5, 73.0, and 74.0 points for university-general hospitals, similar to 77.2, 75.1, 71.0, and 73.8 points for dental hospitals, while dental clinics had 61.1, 40.0, 37.0, and 45.6 points. Prevention and management of staff infection exposure, wearing personal protective equipment, and hand hygiene levels were 90.7, 75.5, 88.5 points for university-general hospitals, 79.8, 79.5, 80.4 points for dental hospitals, and 50.2, 88.0, 61.5 points for dental clinics, respectively. Conclusions: Efforts are required to bring about improvement in the areas of insufficient infection control in order to raise the overall infection control levels, especially the management of dental clinics is urgently needed.

• 대한기계학회논문집A
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• 제40권6호
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• pp.587-593
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• 2016

대체모델을 이용한 신뢰성기반 최적설계에서 최적해와 신뢰도의 정확성은 제한조건경계의 대체모델의 정확도에 영향을 받는다. 기존 제안된 제한조건경계 샘플링 기법은 제한조건경계에 실험점을 생성하여 이러한 정확성을 높일 수 있었다. 하지만, 제한조건경계 샘플링 기법은 최적해와 먼 부근의 제한조건경계에도 불필요한 실험점을 생성하여 과도한 계산비용이 발생한다. 본 논문에서는 크리깅 대체모델의 통계적 정보를 이용하여 최적해 근처의 제한조건경계에 실험점을 생성하는 효율적인 제한조건경계 샘플링 기법을 제안한다. 제안한 기법의 효율성과 정확성은 수학예제를 통하여 확인한다.