• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.71-79
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• 2013

Semiparametric and nonparametric small area estimations have been studied to overcome a large variance due to a small sample size allocated in a small area. In this study, we investigate semiparametric and nonparametric mixed effect small area estimators using penalized spline and kernel smoothing methods respectively and compare their performances using labor statistics.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1169-1178
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• 2010

This article consider a performance model selection based on AIC under unbalanced deign in linear mixed effect models. Vaida and Balanchard (2005) proposed conditional AIC for model selection in linear mixed effect models when the prediction of random effects is of primary interest. Theoretical properties of cAIC and related criteria have been investigated by Liang et al. (2008) and Greven and Kneib (2010). However, all of the simulation studies were performed under a balanced design. Even though functional form of AIC remain same even under the unbalanced deign, it is worthwhile to investigate performance of AIC based model selection criteria under the unbalanced design. The simulation study in this article shows how unbalancedness affects model selection in linear mixed effect models.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.10-17
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• 2000

본 논문은 우주 발사 비행체가 지구 재진입 할 때의 유도제어에 관한 것이다. 우주 발사 비행체의 재진입궤적은 재진입 할 때의 특징에 따라 여러 단계로 나누어진다. 저항가속도는 각 단계에 따라 알맞은 파라메터로 표현되며, 해석적인 저항가속도로 단순화된 궤적으로 표현한다. 본 연구는 현재의 이란적인 궤적방법과 예측방법의 각각의 장점에 의한 혼합유도방법을 표현하였다. 제안된 유도방법을 이용한 우주 발사 비행체의 재진입 모의실험의 결과는 혼합유도방법이 지구대기 재진입 할 때 간단하고 효과적인 유도방법임을 보여주었다.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.24-29
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• 2003

In this paper, a new method for the mixed image separation is presented using the independent component analysis, the innovation process, and the expectation-maximization. In general, the independent component analysis (ICA) is one of the widely used statistical signal processing schemes, which represents the information from observations as a set of random variables in the from of linear combinations of another statistically independent component variables. In various useful applications, ICA provides a more meaningful representation of the data than the principal component analysis through the transformation of the data to be quasi-orthogonal to each other. which can be utilized in linear projection.. However, it has been known that ICA does not establish good performance in source separation by itself. Thus, in order to overcome this limitation, there have been many techniques that are designed to reinforce the good properties of ICA, which improves the mixed image separation. Unfortunately, the innovation process still needs to be studied since it yields inconsistent innovation process that is attached to the ICA, the expectation and maximization process is added. The results presented in this paper show that the proposed improves the image separation as presented in experiments.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.97-102
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• 1995

벨기에, 독일 및 프랑스를 비롯한 유럽의 여러 나라와 일본은 플루토늄을 혼합핵연료로 만들어 경수로에 부분적으로 장전하여 재순환시키는 방법에 대한 연구를 오래전부터 계속하여 현재는 이를 상용화하는 단계까지 왔다. 이전의 혼합핵연료의 경수로에의 이용이 핵연료 자원을 효과적으로 이용하는 측면이 중시되었으나, 최근에는 잉여 플루토늄 처리 및 혼합핵연료의 사용을 일부 원자로에 국한하는 목적으로 혼합핵연료를 노심 전체에 장전하여 사용하는 연구가 진행되고 있다. 따라서 본 논문에서는 혼합핵연료를 가압경수로 노심 전체에 장전하는 개념에 대하여 플루토늄의 소모 및 노심의 핵특성 관점에서 검토하였다. 그 결과 기존의 가압경수로에 혼합핵연료로 전노심을 구성하여 연소시킬 경우 fissile 플루토늄 원소의 초기 장전량이 방출시에는 약 60% 수준으로, 플루토늄의 총량은 약 70% 수준으로 감소하고 있다. 기존의 경수로에 혼합핵연료를 전체적으로 장전하면 900 ㎿급 원자로 1기당 년간 약 1톤가량의 플루토늄이 소요되며, 이를 실현하기 위해서는 제어봉 계통의 추가 설치 및 붕산계통의 고붕산화 등의 설비의 변경과 핵특성 변화에 따른 안전성 분석 등이 필요할 것이다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.1-9
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• 2007

For an efficient implementation of cryptosystems based on arithmetic in a finite field $GF(2^n)$, their hardware implementation is an important research topic. To construct a multiplier with low area complexity, the divide-and-conquer technique such as the original Karatsuba-Ofman method and multi-segment Karatsuba methods is a useful method. Leone proposed an efficient parallel multiplier with low area complexity, and Ernst at al. proposed a multiplier of a multi-segment Karatsuba method. In [1], the authors proposed new $MSK_5$ and $MSK_7$ methods with low area complexity to improve Ernst's method. In [3], the authors proposed a method which combines $MSK_2$ and $MSK_3$. In this paper we propose an efficient multiplication method by combining $MSK_2,\;MSK_3\;and\;MSK_5$ together. The proposed method reduces $116{\cdot}3^l$ gates and $2T_X$ time delay compared with Gather's method at the degree $25{\cdot}2^l-2^l with l>0.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.739-743
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• 2017

Product distribution and consumption in the military is difficult due to unique contracts and supply systems. It is difficult to change suppliers immediately when quality problem is encountered. Due to these special circumstances, the quality of products must be thoroughly controlled. Sesame oil is used to increase the taste and nutrition of food, but it is more expensive than other cooking oils. Oil producers may blend other cooking oils with sesame oil to make higher profits, so it has become important to identify good and bad products. In this study, pure sesame oil and blend oils were compared by analyzing their smell, taste, chemical components, and near infra-red spectra to determine quality differences between them.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.167-176
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• 2021

When producing recycled asphalt mix, it is important that the old binder of reclaimed asphalt pavement(RAP) should be well melted during blending in the mixer. The recycled asphalt mix is produced by instant mixing(IM) of all materials(RAP, virgin asphalt and new aggregates) all together in the mixer. However, in the same recycled mix, the binder around RAP aggregate was found to show higher oxidation level than the binder coated around the virgin aggregate because the old binder of RAP was not rejuvenated properly while instant mixing. The partially-rejuvenated RAP binder is assumed to be a high stiffness point in IM recycled mix. In this study, the stage mixing(SM) method was introduced; blending RAP and virgin asphalt for the first stage, and then mixing all together with hot new aggregates for the second stage. To compare the effect of the two mixing methods on moisture resistance of recycled mixes, a statistical t-test was performed between SM and IM using indirect tensile strength(ITS) and tensile strength ratio(TSR). Three conditioning methods were used; a 16-h freezing and then 24-h submerging, 48-h submerging, and 72-h submerging in 60℃ water. It was found that the TSR(=ITS_wet/ITS_dry) values of the mixes prepared by SM was clearly higher than the IM mixes, and coefficients of variation of SM mixes were lower than the IM mixes. It was also observed that the ITS_WET of SM was significantly different from the IM at α=0.05 level by statistical t-test. The ITS_WET of SM mix was reduced less than the IM mix in severer conditioned mixes. Therefore, it was concluded that the stage mixing method was an important blending technique for producing better-quality of recycled asphalt mixes, which would show higher moisture resistance than the recycled mixes produced by conventional instant mixing.

• Journal of Korean Society of Steel Construction
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• v.14 no.1
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• pp.87-94
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• 2002

In the preceding study, a series of results was presented according to factors like as attaching method of main bar, shear span to depth ratio, reinforcing method for different types of region among various factors, which could determine the properties of composite beams. Based on these results, this study was planned to investigate the structural behaviors of according to attaching method of main bar for composite beams(end-reinforced concrete(RC), center-steel concrete (SC)) varying ratio of tensile bar to steel mainly. Consequently, there were little difference according to attaching method of main bar. And as the ratio of tensile bar to steel increase, the efficiency of strength was high, but ductile capacity of beams could deteriorate. Therefore, to maximize the structural properties of composite beams, it was considered that the ratio of tensile bar to steel should be limited.

• Journal of Korea Society of Industrial Information Systems
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• v.3 no.1
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• pp.101-116
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• 1998

혼합·이산 비선형 최적화문제 해결을 위한 전역적 최적화 알고리즘이 개발되었으며 이 알고리즘은 확률적 최적화기법인 유전알고리즘을 사용한다. 유전알고리즘은 다양한 설계변수를 처리하는데 적합하다. 그러나 기존의 유전알고리즘이 특별히 잘 수행되지 않는 상황이 많이 존재하기 때문에 혼합화에 대한 다앙한 방법이 개발되어지고 있다. 따라서 이 논문은 유전알고리즘에서 최적해 주위에 대한 국고수수렴기법과 정밀 탐색법을 구체화시킨 새로운 혼합유전알고리즘(NHGA)을 개발했다. 사례연구에서는 혼합·이산 비선형 최적화문제를 해결하는데 있어서 NHGA가 상당한 능력을 제공하며 효율적이고 우수한 해를 제공할 수 있다는 것을 보여주고 있다.