• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.608-613
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• 2017

In this paper, we consider the stability bound for uncertainty of delayed state variables in the linear discrete interval time-varying systems with time-varying delay time. The considered system has an interval time-varying system matrix for non-delayed states and is perturbed by the unstructured time-varying uncertainty in delayed states with time-varying delay time within fixed interval. Compared to the previous results which are derived for time-invariant cases and can not be extended to time-varying cases, the new stability bound in this paper is applicable to time-varying systems in which every factors are considered as time-varying variables. The proposed result has no limitation in applicable systems and is very powerful in the aspects of feasibility compared to the previous. Furthermore. the new bound needs no complex numerical algorithms such as LMI(Linear Matrix Inequality) equation or upper solution bound of Lyapunov equation. By numerical examples, it is shown that the proposed bound is able to include the many existing results in the previous literatures and has better performances in the aspects of expandability and effectiveness.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.504-509
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• 2022

In this paper, we deal with the stability condition of linear time-varying interval discrete systems with time-varying delays and unstructured uncertainty. For the time-varying interval discrete system which has interval matrix as its system matrices, time-varying delay time within some interval value and unstructured uncertainty which can include non-linearity and be expressed by only its magnitude, the stability condition is proposed. Compared with the previous result derived by using a upper bound solution of the Lyapunov equation, the new result is derived by the form of simple inequality based on Lyapunov stability condition and has the advantage of being more effective in checking stability. Furthermore, the proposed condition is very comprehensive, powerful and inclusive the previously published conditions of various linear discrete systems, and can be expressed by the terms of magnitudes of the time-varying delay time and uncertainty, and bounds of interval matrices. The superiority of the new condition is shown in the derivation, and the usefulness and advantage of the proposed condition are examined through numerical example.

• Journal of Astronomy and Space Sciences
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• v.5 no.2
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• pp.129-141
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• 1988

Using the numerical solution in the plane restricted problem of three bodies, abut 490 periodic orbits are computed numerically around the $L_5$ of Sun-Jupiter and about 1600 periodic orbits also be done around the $L_5$ of Sun-Jupiter system. But, in Earth-Moon system, the complex shapes and dents appear around the $L_5$ and periodic orbits intersect one another in the place where dents are shown. And there is a region that three different periodic orbits exist with the same period in this system. The increase of energy is in inverse proportion to that of period in the part of this region. The regions can exist around the $L_5$ of Sun-Jupiter system where periodic orbit can be unstable by perturbation of other force besides the gravitational force of Jupiter. These regions which is close to $L_5$ are a~5.12 AU. The Trojan asteroids that have a small eccentricity and inclination can not exist in this region.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.199-207
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• 2019

One philosopher said that knowing the identity of one clump of grass on the roadside could reveal all the mysteries of the universe. If you know one, you can know two. If you know two, you can know three. If you know the form, you can know the whole. If you know the image(eidos), you can know the non-image, life, and death. But we are wandering in a dream because we don't know the one clump of grass, "One". For a long time I have been searching for a road to know "One". While studying of the process searching the truth, not only do we reveal logic development making One a language, but also we would like to provide the application of cultural contents applied to that One.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.37-46
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• 2006

The principal objective of this study is to assess the hierarchical effects of defects on the elastic stiffness properties at different levels of observation. In particular, quantitative damage measures which characterize the fundamental mode of degradation in the form of elastic damage provide quite insightful meanings at the level of constitutive relations and at the level of structures. For illustration, a total of three model problems of increasing complexity, a 1-D bar structure, a 2-D stress concentration problem, and a heterogeneous composite material made of a matrix with particle inclusions. Considering a damage scenario for the particle inclusions the material system degrades from a composite with very stiff inclusions to a porous material with an intact matrix skeleton. In other damage scenario for the matrix, the material system degrades from a composite made of a very stiff skeleton to a disconnected assembly of particles because of progressive matrix erosion. The trace-back and forth of tight bounds in terms of the reduction of the lowest eigenvalues are extensively discussed at different levels of observation.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.4
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• pp.783-787
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• 2012

It is not easy to find out syntactic error in a spelling checker systems of Korean, because the spelling checker is generally to correct each phrase and it cannot check the errors of contextual ill-matched words. Spelling checker system tests errors based on a words. Disambiguation of lexical ambiguities is important in natural language processing. Its outputs is used in syntactic analysis. For accurate analysis of a sentence, syntactic analysis system must find out the ambiguity of morphemes in a word. In this paper, we suggest several rules to resolve the ambiguities of morphemes in a word. Using these methods, we can reduce many lexical ambiguities in Korean.

• The Korean Journal of Financial Management
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• v.9 no.2
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• pp.31-55
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• 1992

금융기관(金融機關)은 기업, 가계, 정부와 함께 우리 경제를 구성하는 주요한 부분이다. 금융기관은 최종적 차입자와 최종적 대부자를 중개하는 과정에서 여러가지 서어비스를 우리에게 제공하면서 존재한다. 금융기관이 제공하는 서어비스는 우리의 경제생활에 매우 중요한 영향을 미친다. 금융기관의 행동이 경제에 미치는 영향을 분석하기에 앞서 어떤 조건하에서 금융기관이 존립할 수 있는가를 알아보는 것도 금융기관의 행동을 이해하기 위해 의미있는 일일 것이다. 본 논문은 정보불균형(情報不均衡)의 관점에서 금융기관의 존립을 분석, 설명하는데 그 목적이 있다. 경제문제의 불확실성과 복잡성의 증대는 민간의 제한된 합리성을 더욱 제한되게 만들고 역으로 제한된 합리성 때문에 불확실성과 복잡성은 더욱 중요한 문제가 된다. 여기에다 인간의 이기주의가 결합하게 되면 정보의 유통이 불완전해져 정보가 불균등하게 분포하게 되는 현상이 생긴다. 정보불균형(情報不均衡)은 거래를 위촉시키고 극단적인 경우 시장실패(市場失敗)를 가져온다. 금융기관은 정보생산을 통해 거래위축이나 시장주패(市場朱敗)를 방지할 수 있는 역할을 한다. 금융기관이 정보생산을 한다고 해도 개별정보생산자나 직접 금융에 비해 정보생산비용면에서 우위를 가질 수 있어야 금융기관의 존립은 가능할 것이다. 즉 정보불균형(情報不均衡)을 해소하기 위한 정보생산이 금융기관이 존립할 수 있는 필요조건이라면, 정보생산의 경제성은 금융기관이 존립할 수 있는 필요충분조건이 된다고 할 수 있다. 금융기관이 개별정보생산자나 직접 금융보다 정보생산면에서의 경제성을 가질 수 있는 가능성은 첫째, 분산효과(分散效果)로 인한 대리비용(代理費用)의 감소(減小) 둘째, 분산효과(分散效果)로 인한 구성원보상(構成員補償)의 불확실성감소(不確實性減小) 세째, 금융기관 구성원간의 정보공유효과(情報共有效果)이다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.347-358
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• 2004

In Mongolia which consists of nomadic populations, horse has been loved by nomads and considered most important transportation means. Horses have been used when they were making long journey looking for new plain ground for grazing. Therefore, horse is closely connected with Mongolian nomadic culture. In Korea, too, horses had been considered one of most important means for transportation and military. The symbolism of horse that is represented in both Mongolia and Korea is Heavenly Horse which communicates with the God and it was sanctified as a Sacrificing Horse which was sent to God for sacrifice, and it was even worshiped as Divine Horse, the diety. As is the case of two of Mongolian customs associated with Mongolian language are 'the ceremony of horse's giving birth her young' and 'the ceremony of letting the mare go where it was before', all the cases are related with cattle's milk. The ceremony of 'horse's giving birth her young' is the ceremony where people hope that they would see the young can grow well which were born in early summer thus increasing the numbers of horse. To go with this, they perform a ceremony of Chachal in which they sprinkle the best quality white milk which is the symbol of good luck and hope they would produce plentiful of dairy products. The ceremony of 'letting the mare go where it was before' is also the ceremony where people hope to have many new born young horses thus produce more dairy products and Airag for the next year as milking is no more available for that you. Since the unified Silla Era, Koreans have performed a sacrifice rituals to horse in auspicious day. It's purpose is to see their horses get no disease and bear as many youngs as possible. The Back Ins Je, one of well blown festivals in Jeju Island, was originated from people's wish to prosper in stock farming. It can be said that the custom of Korea and Mongolia related with horse's giving birth was originated from the wishes to god for fertility and fecundity. On top of that, while Mongolians sprinkled horse's milk both on the ground and to the air hoping they would have increased houses and, thus, secure many dairy products, Koreans wish that they would see the increased number of horses and their healthy conditions through heavenly rituals.

• Journal of KIISE:Software and Applications
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• v.33 no.4
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• pp.440-448
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• 2006

Self-Organizing Map (SOM) is an unsupervised learning neural network and it is used for preserving the structural relationships in the data without prior knowledge. SOM has been applied in the study of complex problems such as vector quantization, combinatorial optimization, and pattern recognition. This paper proposes a new usage of SOM as a tool for schema transformation hoping to achieve more efficient genetic process. Every offspring is transformed into an isomorphic neural network with more desirable shape for genetic search. This helps genes with strong epistasis to stay close together in the chromosome. Experimental results showed considerable improvement over previous results.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.524-531
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• 2001

Micro-HPLC/IS/MS after solid phase extraction has been employed to enhance the accu-racy in the determination of toxic microcystins, such as microcystin-LR, -YR and -RR. The absorbance at 238 nm in HPLC/UV and characteristic spectra of 135 m/z and $[M+H]^+$ m/z in MS have been widely monitored to identify those microcystin-LR, -YR and -RR. In this study, new lines at 507 m/z for LR, 520 m/z for RR and 532 m/z for YR have been additionally detected in the micro-HPLC/IS/MS spectrum, corresponding to double charge. The micro-HPLC/IS/MS methodology has been applied to investigate the presence of the toxic microcystins in Taecheong lake.