• 한국경영과학회지
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• 제25권1호
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• pp.37-50
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• 2000

We are concerned with estimating the average performance of a re-entrant line with single-job machines and batch machines. The system has multiclass jobs, which will be processed in predetermined routes. An analytical approach may be intractable since the system would not be modeled by product form queueing networks due to the inclusion of batch machines and the consideraton of multiclass jobs which have different processing times. We propose an approximation method based on the Mean Value Analysis(MVA). Our method obtains the mean walting time in each buffer of a workstation and the mean cycle time using the MVA and heuristics. numerical experiments show that the errors of our method are within 5% compared with simulation.

• 한국산업융합학회 논문집
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• 제8권4호
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• pp.221-226
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• 2005

This paper presents a hybrid method for recognizing the faces by using zero mean and principal component analysis. Zero mean is applied to reduce the 1st order statistics to data nonlinearities. PCA is also used to derive an orthonormal basis which directly leads to dimensionality reduction, and possibly to feature extraction of face image. The proposed method has been applied to the problems for recognizing the 20 face images(10 persons * 2 scenes) of 324*243 pixels from Yale face database. The 3 distances such as city-block, Euclidean, negative angle are used as measures when match the probe images to the nearest gallery images. The experimental results show that the proposed method has a superior recognition performances(speed, rate). The negative angle has been relatively achieved more an accurate similarity than city-block or Euclidean.

• 한국통신학회논문지
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• 제22권10호
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• pp.2303-2309
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• 1997

본 논문에서는 고차통계에 의한 적응알고리즘 가운데 오차의 평균절대값삼승(LMAT)을 최소화하는 알고리즘의 수렴특성에 대하여 분석하였다. 사용된 입력신호가 Gaussian 분포를 갖는다는 가정하에 알고리즘의 평균자승 추정오차와 필터계수의 평균 및 평균자승 특성에 대해 정량적인 분석을 수행하였으며, 이에 대한 관계식을 각각 유도하였다. 이론적으로 분석된 결과는 컴퓨터 모의실험에 의하여 그 타당성을 검증하였고, 이론치와 실험치가 거의 일치함을 확인하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제4권2호
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• pp.89-96
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• 2015

In this paper, time-frequency analysis algorithms, empirical mode decomposition and local mean decomposition, are reviewed and their applications to nonlinear and nonstationary real-world data are discussed. In addition, their generic extensions to complex domain are addressed for the analysis of multichannel data. Simulations of these algorithms on synthetic data illustrate the fundamental structure of the algorithms and how they are designed for the analysis of nonlinear and nonstationary data. Applications of the complex version of the algorithms to the synthetic data also demonstrate the benefit of the algorithms for the accurate frequency decomposition of multichannel data.

• The Journal of the Acoustical Society of Korea
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• 제27권2E호
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• pp.64-68
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• 2008

This paper investigates noise reduction performance and performs convergence analysis of a Variable Error Data Normalized Step-Size Least Mean Square(VEDNSS LMS) algorithm. Adopting VEDNSS LMS results in higher system complexity, but noise is reduced providing fast convergence speed Mathematical analysis demonstrates that tap coefficient misadjustment converges. This is confirmed by computer simulation with the proposed algorithm.

• 한국방사선학회논문지
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• 제12권6호
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• pp.755-762
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• 2018

유방암을 진단받고 수술 전 확산텐서영상에서 도출된 정량적 확산 지표인 비등방성 확산의 크기(FA)와 현성 확산계수(ADC) 값을 비교하고, 상관관계를 분석하여 보기로 하였다. 확산 그레디언트는 20방향(b-value, 0 및 $1,000s/mm^2$)을 사용하여 정량적 확산 지표를 도출하였다. 정량적 분석은 피어슨의 상관분석, 정성적 분석은 급내 상관계수를 적용하여 분석하였다. 연구 결과는 FAmin, FAmean, FAmax 평균값은 $0.098{\pm}0.065$, $0.302{\pm}0.142$, $0.634{\pm}0.236$이고 ADCmin, ADCmean, ADCmax은 $0.741{\pm}0.403$, $1.095{\pm}0.394$, $1.530{\pm}0.447$로 나타났다(p > 0.05). 병변 평가에서 Category 6이면서 시간대 신호 강도 그래프가 유실형(Pattern III)의 경우는 $FA_{min}$, $FA_{mean}$, $FA_{max}$ 평균값은 $0.132{\pm}0.050$, $0.418{\pm}0.094$, $0.770{\pm}0.164$이고 $ADC_{min}$, $ADC_{mean}$, $ADC_{max}$는 $0.753{\pm}0.189$, $1.120{\pm}0.236$, $1.615{\pm}0.372$로 나타났다. 정량적 분석 결과 $ADC_{mean}-FA_{mean}$, $ADC_{maximal}-FA_{max}$는 음의 상관관계가 나타났다(p = 0.001, 0.003). 정성적 분석 결과 내부 평가자의 경우 ADC 0.628(p = 0.001), FA 0.620(p = 0.001)이고, 외부 평가자의 경우 ADC 0.677(p = 0.001), FA 0.695(p = 0.001)로 나타났다. 결론적으로 형태학적 조직 검사를 바탕으로 동적 조영 검사에서 시간대 신호 강도 그래프는 유실(pattern III: wash out) 형태이며, $ADC_{mean}$ $1.120{\pm}0.236$, $FA_{mean}$값이 $0.032{\pm}0.142$로 피어슨 상관분석의 결과 음의 상관관계(Y=1.44-1.12X)로 나타났다. 따라서, 시간대 신호강도 그래프의 형태와 ADC와 FA의 상호관계를 파악한다면 유방암에서 악성 질환을 구분하는 기준이 되리라 생각된다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권3호
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• pp.213-224
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• 2011

In this paper, we analyze statistically the data set of first leak time of water pipeline. We classify first the leak time data by pipe type, location, diameter of pipe and, length of pipe. We perform the analysis of variance to indicate that there are significant difference of mean of the time between levels of the factor and also compare the distribution of levels using the multiple box-plot. When there are the difference of the mean, we perform the least significant test to find out what levels of the facor has a different mean.

• Archives of Pharmacal Research
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• 제12권4호
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• pp.289-294
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• 1989

A computer program which can differentiate compounds whose absorbance spectra are very similar was developed. The program. [SPECMAN PLUS], written in Pascal provides automated spectral comparison techniques, utilizing the values of Root Mean of Squares (RMS) of differences. This comparison routine of the program can deal with spectra of compounds different concentrations and different spectral recording resolutions. In addition, the program was designed applicable to any spectral data of digital form. The program was applied to the UV spectra of 13 pencillins and 5 cephalosporins, whose absorbance spectra are so similar. As a result, all compounds examined could be differentiated from each other.

• The Journal of the Acoustical Society of Korea
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• 제16권1E호
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• pp.41-48
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• 1997

The very purpose of subband codec is the attainment of data rate compression through the use of quantizer and optimum bit allocation for each decimated signal. Yet the question of floating-point quantization effects in subband codec has received scant attention. There has been no direct focus on the analysis of quantization errors, nor on design with quantization errors embedded explicitly in the criterion. This paper provides a rigorous theory for the modelling, analysis and optimum design of the general M-band subband codec in the presence of the floating-point quantization noise. The floating-point quantizers are embedded into the codec structure by its equivalent multiplicative noise model. We then decompose the analysis and synthesis subband filter banks of the codec into the polyphase form and construct an equivalent time-invariant structure to compute exact expression for the mean square quantization error in the reconstructed an equivalent time-invariant structure to compute exact expression for the mean square quantization error in the reconstructed output. The optimum design criteria of the subband codec is given to the design of the analysis/synthesis filter bank and the floating-point quantizer to minimize the output mean square error. Specific optimum design examples are developed with two types of filter of filter banks-orthonormal and biorthogonal filter bank, along with their perpormance analysis.

• 한국멀티미디어학회논문지
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• 제20권6호
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• pp.935-949
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• 2017

The purpose of this study was to analyze the characteristics of virtual manipulatives apps that can be used to teach students struggling to learn mathematics. To achieve this goal, ten general characteristics of 23 virtual manipulatives apps were evaluated. The instructional, interface, and interactive design features of apps were also evaluated on five-point scale ratings of 18 items. In addition, SPSS frequency analysis and the correlation between each feature was analyzed. Frequently presented instructional contents among 23 virtual manipulatives apps were geometry, arithmetic operation, number concept and measurement. The frequently presented level of instructional contents was lower grade elementary school and kindergarten age. The frequently presented instructional type was the simulation. Regarding the design features, instructional design was rated as the highest (mean = 3.7); interactive design (mean = 3.6) and interface design (mean = 3.3) were also rated higher than neural. In addition, as the learning strategy was appropriately presented, it was evaluated that there was less screen linkage and content error.