• JSTS:Journal of Semiconductor Technology and Science
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• 제16권5호
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• pp.624-629
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• 2016

The influence of electron and hole (EH) distribution on two-transistor (2T) silicon-oxide-nitride-oxide-silicon (SONOS) embedded nonvolatile memory (eNVM) is investigated in terms of reliability. As PE (program/erase) cycles are repeated, it is observed that the electron distribution in the nitride layer becomes wider. It leads to the EH distribution mismatch, which degrades the reliability of 2T SONOS eNVM.

• Journal of the Korean Data and Information Science Society
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• 제21권6호
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• pp.1327-1335
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• 2010

In this paper, we want to develop objective priors for the common location parameter in two half-t distributions with unequal scale parameters. The half-t distribution is a non-regular class of distribution. One can not develop the reference prior by using the algorithm of Berger of Bernardo (1989). Specially, we derive the reference priors and prove the propriety of joint posterior distribution under the developed priors. Through the simulation study, we show that the proposed reference prior matches the target coverage probabilities in a frequentist sense.

• Communications for Statistical Applications and Methods
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• 제5권3호
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• pp.887-894
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• 1998

Let T=( $T_1$,…, $T_{k}$;k$\geq$2) be a minimal sufficient and complete statistic for a k-parameter exponential model. Consider a partition of T into ( $T_1$, $T_2$), where $T_1$=( $T_1$,…, $T_{r}$ and $T_2$=( $T_{r+1}$,…, $T_{k}$1$\leq$r$\leq$k-1/). This article represents a way to obtain higher moments such as skewness and kurtosis for the distribution T and the conditional distribution of $T_1$, given $T_2$= $t_2$. These results are illustrated by some examples.s.les.s.

• 자원ㆍ환경경제연구
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• 제16권4호
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• pp.947-978
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• 2007

본 연구에서는 원유시장의 변동성 분석에 적용될 수 있는 VaR(Value-at-Risk) 접근법을 고찰한다. 그리고 다양한 VaR 모형들(RiskMetrics, GARCH, IGARCH와 FIGARCH 모형)의 성과를 정규분포와 치우친 Student-t 분포 가정 하에서 평가한다. Brent 및 Dubai 시장의 일별가격 자료를 이용한 실증분석 결과에 따르면, FIGARCH 모형이 GARCH 모형이나 IGARCH 모형보다 원유시장의 변동성에 내재되어 있는 장기기억 특성을 잘 반영한다는 점에서 더 우월한 것으로 나타났다. 이러한 사실은 원유시장 수익률의 변동성에는 장기기억이 존재한다는 것을 의미한다. 그리고 VaR 분석 결과, 치우친 Student-t 분포 가정 하에서 추정되는 FIGARCH 모형이 롱 포지션과 숏 포지션 모두에서 정규분포 가정 하에서 추정되는 다른 변동성 모형들보다 원유시장에서의 투자 위험을 더 정확하게 예측하는 것으로 나타났다. 이러한 사실은 치우친 Student-t 분포 가정이 원유시장 수익률 분포에 내재되어 있는 비정상적 왜도와 첨도를 모형화하는데 더 적합하다는 것을 의미한다. 이와 같은 발견은 원유시장 구매자 및 판매자들이 원유가격의 움직임을 올바르게 측정하고 VaR을 정확하게 추정하는데 도움을 줄 것이다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1081-1083
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• 2007

The study in river basin has been performed for the identify water quality impaired stream segments, to create a priority ranking of those segments, and to calculate the heavy metal ion distribution for each impaired segment based on chemical and physical water quality standards. Two methods for modeling the potential area-specific heavy metal distribution are pursued in this study. First, a novel approach focuses on distance. Heavy metal distribution can be associated with a particular small geographic area. Based on the derived estimates an distribution map can be generated. Second, the approach is used the near watershed by means of kriging interpolation algorithm. These approaches provide an alternative distribution mapping of the area. The exposure estimates from both of these modeling methods are then compared with other environmental monitoring data. A GIS-based model will be used to mimic the hierarchical stream structure and processes found in natural watershed. Specifically, the relationship between landscape variables and reach scale habitat conditions most influential found in the Abandoned mine will be explored.

• Journal of the Korean Data and Information Science Society
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• 제20권3호
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• pp.587-592
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• 2009

The most frequent use of the chi-square distribution is in the area of goodness-of-t of a distribution. The likelihood ratio test is a commonly used test statistic as the maximum likelihood estimate in statistical inferences. The recently revised versions of the likelihood ratio test statistics are used in estimating the parameter in the chi-square distribution. The estimates are compared with the commonly used method of moments and the maximum likelihood estimate.

• Communications for Statistical Applications and Methods
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• 제25권2호
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• pp.109-130
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• 2018

Several measures of multivariate skewness for scale mixtures of skew-normal distributions are derived. As a special case, those of multivariate skew-t distribution are considered in detail. Furthermore, the similarities, differences, and behavior of these measures are explored for cases of some specific members of the multivariate skew-normal and skew-t distributions using a simulation study. Since some measures are vectors, it is better to take all measures in the same scale when comparing them. In order to attain such a set of comparable indices, the sample version is considered for each of the skewness measures that are taken as test statistics for the hypothesis of t distribution against skew-t distribution. An application is reported for the data set consisting of 71 total glycerol and magnesium contents in Grignolino wine.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.717-727
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• 2006

The present study experimentally investigated the effect of flow direction and other flow parameters on two-phase flow distribution of refrigerants at a T-junction, and also suggested a prediction model for refrigerant in a T-junction by modifying previous model for air-water flow. R-22, R-134a, and R-410A were used as test refrigerants. As geometric parameters, the direction of the inlet or branch tube and the tube diameter ratio of branch to inlet tube were chosen. The measured data were compared with the values predicted by the models developed for air-water or steam-water mixture in the literature. We propose a modified model for application to the reduced T-junction and vertical tube orientation. Among the geometric parameters, the branch tube direction showed the biggest sensitivity to the mass flow rate ratio for the gas phase, while the inlet quality showed the biggest sensitivity to the mass flow rate ratio among the inlet flow parameters.

• 설비공학논문집
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• 제11권5호
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• pp.579-587
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• 1999

The flow distribution characteristics in a complex duct system have been investigated in this paper by three means, namely experimental measurement, numerical simulation and the Extended T-method analysis. While the exit flow rates predicted by the three-dimensional CFD calculation and those given by the experiment show a close agreement, the results from the one-dimensional Extended T-method are found to differ from the experiment by -22.2% to 26.3% for the various exits. These discrepancies may be attributed to the underlying limitation concerning the fitting loss coefficients, which assume that the flow in front of the fittings is fully developed. It is proposed that, in order to analyse the three-dimensional flow distributions in a complex duct system by one-dimensional analysis such as the Extended T-method, further Improvements to the fitting loss coefficients should be made.

• 대한한의학회지
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• 제27권2호
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• pp.244-252
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• 2006

Objectives : To examine any potential relationships between the types of alopecia and the facial heat distribution in patients with alopecia. Methods : 183 patients with alopecia participated in this study to provide facial heat distribution measured by the Infrared Thermography Scanner (ITS, Nec San-ei Instruments Ltd, Japan). The thermography scan was used in a light- and heat-protected room after 20 minutes' of rest. 1.5m of distance was maintained between the patients and the scanner. Results : Specificity in the type of facial heat distribution was found as follow. 1. Types of facial heat distribution can be classified as T-type and diffused patterns. 2. There was a significant difference in the pattern of facial heat distribution among different types of alopecia (p=0.002): facial heat distribution appeared T-type in androgenic alopecia, alopecia areata, and telogen effluvium (71.3%, 85.7%, 70.4%), whereas diffused pattern was dominant in seborrheic alopecia (55.6%). 3. There was a significant difference in the pattern of facial heat distribution between men and women (p<0.001) : While the T-type and diffused type appeared equally in men (50.6% : 49.4%), T-type was dominant in women (88.0% vs. 12.0%). Conclusions : We conclude that the pattern of facial heat distribution differs depending on the types of alopecia and gender. These differences may provide useful information for diagnosis and clinical therapy for this population.